Podcasts about acyl

References Front Immunol. 2023; 14: 1151166 --- Send in a voice message: https://podcasters.spotify.com/pod/show/dr-daniel-j-guerra/message Support this podcast: https://podcasters.spotify.com/pod/show/dr-daniel-j-guerra/support

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2023.07.31.551267v1?rss=1 Authors: Liu, A., Kage, F., Sapp, G., Aydin, H., Higgs, H. N. Abstract: Mitochondrial fission occurs in many cellular processes, but the regulation of fission is poorly understood. We show that long-chain acyl coenzyme A (LCACA) activates two related mitochondrial fission proteins, MiD49 and MiD51, by inducing their oligomerization, activating their ability to stimulate DRP1 GTPase activity. The 1:1 stoichiometry of LCACA:MiD in the oligomer suggests interaction in the previously identified nucleotide-binding pocket, and a point mutation in this pocket reduces LCACA binding and LCACA-induced oligomerization for MiD51. In cells, this LCACA binding mutant does not assemble into puncta on mitochondria or rescue MiD49/51 knock-down effects on mitochondrial length and DRP1 recruitment. Furthermore, cellular treatment with the fatty acid analogue 2-bromopalmitate, which causes increased acyl-CoA, promotes mitochondrial fission in an MiD49/51-dependent manner. These results suggest that LCACA is an endogenous ligand for MiDs, inducing mitochondrial fission and providing a potential mechanism for fatty acid-induced mitochondrial fragmentation. Finally, MiD49 or MiD51 oligomers synergize with MFF, but not with actin filaments, in DRP1 activation, suggesting distinct pathways for DRP1 activation. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

References Cancer Cell 2020. 40, Issue 4, Pages 365-378.e6 Circulation Research. . 2004 May 28;94(10):1318-24. Mol Cell. 2020 Jun 18;78(6):1192-1206.e10 Cell. 2012 Aug 17;150(4):685-96 Cell Death Differ. 2020 May; 27(5): 1660–1676. --- Send in a voice message: https://anchor.fm/dr-daniel-j-guerra/message Support this podcast: https://anchor.fm/dr-daniel-j-guerra/support

References&Inspirations Guerra intermediary metabolic lectures https://youtu.be/nDidA8_gfbU --- Send in a voice message: https://anchor.fm/dr-daniel-j-guerra/message

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2022.11.05.515282v1?rss=1 Authors: Lujan, A. L., Foresti, O., Brouwers, N., Mateo Farre, A., Vignoli, A., Wojnacki, J., Malhotra, V. Abstract: We show that TANGO2, which lacks a transmembrane domain localizes predominantly to mitochondria and transiently to endoplasmic reticulum (ER) and lipid droplets (LDs). Evaluation of lipids in HepG2 cells lacking TANGO2 revealed an increase in the size of lipid droplets and reactive oxygen species production. There is also a marked increase lysophosphatidic acid (LPA) and a concomitant decrease in its biosynthetic precursor phosphatidic acid (PA). These changes are exacerbated in nutrient starved cells. Based on our data, we suggest that the principle function of TANGO2 is in acyl-CoA metabolism, which is necessary for the acylation of LPA to generate PA. This defect subsequently affects metabolism of many other fatty acids. These data help explain the physiological consequence of TANGO2 that induce acute metabolic crisis including rhabdomyolysis, cardiomyopathy and cardiac arrhythmias often leading to fatality upon starvation and stress. Copy rights belong to original authors. Visit the link for more info Podcast created by Paper Player, LLC

MCAD deficiency is a fatty acid oxidation disorder. It is a hereditary disease that is caused by a missing enzyme needed to convert fat into energy. Children with MCAD deficiency therefore cannot fast for very long without developing hypoglycaemia, which can cause brain damage or even death. This is because they cannot use fat and hence ketones as an alternative energy source as the glucose available to them runs low. Follow us on Instagram @yourekiddingrightdoctors Our email is yourekiddingrightpod@gmail.com Make sure you hit SUBSCRIBE/FOLLOW so you don't miss any episodes and RATE to help other people find us! (This isn't individual medical advice, please use your own clinical judgement and local guidelines when caring for your patients)

Dr David Olsson discusses the Swedish experience following the introduction of newborn screening for VLCAD deficiency. Very long-chain acyl-CoA dehydrogenase deficiency in a Swedish cohort: Clinical symptoms, newborn screening, enzyme activity, and genetics David Olsson, et al https://doi.org/10.1002/jmd2.12268

Dr. Carolyn Lam: Welcome to Circulation on the Run, your weekly podcast summary and backstage pass to The Journal and its editors. We're your co-hosts, I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore. Dr. Greg Hundley: And I'm Dr. Greg Hundley, associate editor, director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well Carolyn, it's another double feature Tuesday and today we get to discuss two articles. One, some insights from the CREDENCE trial. And second, another article about left atrial appendage closure devices, some results from the PINNACLE FLX trial. But before we get to those, how about we grab a cup of coffee and dive into some of the other really interesting articles in this issue? Would you like to go first? Dr. Carolyn Lam: I would, because this next paper, right up your alley and I'm sure you'll like it. But first, we talk about mitral valve prolapse. Now, we know that's a frequent disease that can be complicated by mitral regurgitation, heart failure, arterial embolism, rhythm disorders, and death. Left ventricular replacement myocardial fibrosis is a marker of maladaptive remodeling and has been described in patients with mitral valve prolapse. However, the implications of this finding remain scarcely explored. So these authors, led by Dr. [Le] Tourneau from Hôpital Laennec in France, aimed at assessing the prevalence, pathophysiological and prognostic significance of left ventricular replacement myocardial fibrosis through late gadolinium enhancement by cardiac magnetic resonance in 400 patients with mitral valve products. I bet you like that, right Greg? Dr. Greg Hundley: Oh my gosh Carolyn, not only a favorite topic of cardiovascular magnetic resonance, but this is a really large patient population with mitral valve prolapse that underwent CMR. So tell us, what did they find? Dr. Carolyn Lam: So replacement myocardial fibrosis was observed in 110 patients, so that's 28% of the patients. It was associated with mitral valve apparatus alterations, left ventricular remodeling, and ventricular arrhythmia. The ventricular arrhythmias were more frequent in patients with replacement fibrosis, but were not associated with the grade of mitral regurgitation. In patients with trace or mild mitral regurgitation, the presence of replacement myocardial fibrosis was nonetheless associated with specific mitral valve apparatus alteration at normal left ventricular dilatation, not explained by volume overload and ventricular arrhythmias, suggesting the presence of a mitral valve prolapse-associated cardiomyopathy. Dr. Greg Hundley: Wow Carolyn, really interesting. So the late gadolinium enhancement and the evidence therefore of replacement myocardial fibrosis that was identified by CMR, maybe this particular study is suggesting that we might want to integrate that into the clinical workup of patients with mitral valve prolapse. Very interesting work, and great job on that fantastic CMR presentation. I must say, got to recruit you into the club. Dr. Greg Hundley: Well, my next paper is another wonderful paper from the world of basic science and it comes from Dr. Douglas Lewandowski at the Ohio State University College of Medicine. So Carolyn, the failing heart is energy starved with impaired oxidation of long chain fatty acids at the level of reduced carnitine palmitoyltransferase-1, or CPT-1, activity at the outer mitochondrial membrane. Recent work shows that elevated ketone oxidation and failing hearts as an alternate carbon source for oxidative ATP generation. So Carolyn, these authors hypothesized that another short chain carbon source, short chain fatty acids that bypass CPT-1, could similarly support energy production in failing hearts. Dr. Carolyn Lam: Wow. Okay, so what did they find? Dr. Greg Hundley: So Carolyn, the failing heart oxidizes short-chain fatty acids more readily than ketones, with short-chain fatty acids also displacing long-chain fatty acid oxidation to somewhat of a greater extent. So in particular, the short-chain fatty acid butyrate has a higher affinity for entry into mitochondrial oxidation at the enzyme, short-chain Acyl-CoA dehydrogenase than does the ketone 3-hydroxybutyrate at the hydroxy butyrate dehydrogenase and then also through the respective downstream metabolic pathways for each substrate. So Carolyn, failing hearts of rats and humans have increased levels of Acyl coenzyme A synthetase medium chain three enzyme, which can also oxidize short-chain fatty acids to enhance butyrate oxidation. Dr. Carolyn Lam: Wow, that really is interesting. I can't say that I would have predicted that result. So could you give us a clinical implication? Dr. Greg Hundley: You bet, Carolyn. A lot of basic science here. So here's I think what we can take home, and what we learned. So while ketones have been sought as a potential supplemental fuel to remedy the impaired oxidative metabolism of the failing heart, this study shows that failing hearts preferentially oxidize short-chain fatty acids over ketones and short-chain fatty acids may prove to be a more efficient energy source during pathological stress. Dr. Greg Hundley: Next, novel alterations in metabolic pathways, favoring short-chain fatty acid oxidation in the failing heart occur in patients with non-ischemic cardiomyopathy. Then finally, circulating ketones are not a unique, super fuel beyond the ability to bypass the inhibition of long-chain fatty oxidation in the failing heart, as do the short chain fatty acids. Dr. Carolyn Lam: Thanks, I like the way you broke down the clinical implications. Well, Greg, I've got a question for you. Have you ever thought that statins may do more than lower cholesterol, but depending on what you eat? Dr. Greg Hundley: Oh wow, Carolyn. We always hear about the pleiotropic effects of statins, but I never really thought that could depend on what you eat. Tell me, so what did these authors investigate? Dr. Carolyn Lam: Yeah, so this next paper is so interesting. It's from Dr. Hu from Huazhong University of Science and Technology in Wuhan, China and colleagues, who present a novel perspective on the story of the pleiotropic effects of statins, exactly like you said, Greg. They started with the premise that statins exert pleiotropic or cholesterol-independent effects by reducing geranylgeranyl pyrophosphate production. I'm not going to keep saying that, so geranylgeranyl pyrophosphate or GGPP, is how I'm going to refer to it. Dr. Carolyn Lam: So they developed a sensitive technique to quantify dietary GGPP, and conducted proteomics, RT-PCR screening, and western blot, to determine signaling cascades, gene expression, protein-protein interaction, and protein-membrane trafficking in wild-type and transgenic rats, focusing on models of pulmonary hypertension, given their interest in the potential therapeutic efficacy of statins in pulmonary arterial hypertension. Dr. Greg Hundley: Interesting, Carolyn. Really complex and sophisticated. So what did they find? Dr. Carolyn Lam: Okay, listen up. Red meat and soybean have a high content of GGPP and their ingestion increases GGPP plasma levels, but reduces the effects of statins in rat models of pulmonary hypertension. Ingestion of garlic extracts, rich in methyl-L-phenyl sulfonate, which is a natural inhibitor of GGPP production, decreases GGPP bioavailability, and rescues statin effects in pulmonary arterial hypertension models. So consequently, first of all, diet may influence the cholesterol-independent effects of statins and the data really raise a provocative question of whether populations in which the typical diet contains high amounts of soybeans of beef may benefit less from statins. All this is discussed in an elegant editorial by Dr. Thomas Eschenhagen from Germany, who really ends with saying the present study should be considered hypothesis-generating and stimulate retrospective analysis of clinical registries and existing large interventional trials to either validate or refute this hypothesis. Whatever the outcome, the study is a nice example of thorough scientific underpinning of the widely held maxim that we are what we eat. Dr. Greg Hundley: Oh, absolutely Carolyn. I think next time with my spaghetti, I'll have the- Dr. Carolyn Lam: Garlic. Dr. Greg Hundley: ... sauce with the garlic, but I won't add the red meats. Especially if I'm taking a statin. Dr. Carolyn Lam: Oh, that's what I was afraid you might say. Oh well, let me tell you about other papers in this issue. There's an ECG challenge by Dr. Del-Carpio Munoz and entitled A Carousel ECG Confusion. There's an on my mind paper by Dr. Hammond, on the importance of shared decision making for return to play after COVID-19. Dr. Greg Hundley: Great, Carolyn. So, in the mailbag, there's a really nice research letter from Dr. Robert-Ebadi evaluating the impact of the age-adjusted D-dimer cutoff to exclude pulmonary embolism. It's from a multinational prospective real-life study or the RELAX-PE study. Well Carolyn, it's another double feature Tuesday. How about we get off to understand a little bit more about those insights from the CREDENCE trial, and then also left atrial appendage closure devices? Dr. Carolyn Lam: All right, come on with your garlic breath. Dr. Greg Hundley: Well listeners, we are onto our feature discussions and we are very fortunate, we're going to have two feature discussions. Our first feature really addresses high blood pressure. And we have with us today, Dr. Brendan Neuen from the George Institute of Global Health in Sydney, New South Wales, Australia. And our own associate editor, Dr. Wanpen Vongpatanasin from UT Southwestern in Dallas, Texas. Welcome to you both. Brendan, we're going to start with you. Could you describe the hypothesis that you wanted to test and what was your study population and your study design? Dr. Brendan Neuen: Well, thanks Greg. In this study, what we wanted to assess was the blood pressure lowering effects of the SGLT-2 inhibitor canagliflozin in people with type two diabetes and chronic kidney disease. The reason we thought that this is important is because what we know about the blood pressure lowering effects of these drugs is largely based on people with normal kidney function, with relatively less data in people with chronic kidney disease. So we aim to assess both the blood pressure lowering effects of SGLT-2 inhibition in chronic kidney disease, as well as treatment effects by baseline blood pressure and other blood pressure defined variables. This was conducted in the CREDENCE trial, which was a large primary renal outcome trial of the SGLT-2 inhibitor, canagliflozin, which enrolled about 4,400 people with type two diabetes and chronic kidney disease with a urine albumin to creatinine ratio greater than 300 milligrams per gram and a GFR greater than 30 at enrollment. This was a high risk hypertension population, about 30% of patients had apparent treatment resistant hypertension, about 60% of people had a GFR less than 60 and about 20% of people were on four or more blood pressure lowering agents. So really high burden of hypertension in the CREDENCE trial. Dr. Greg Hundley: Very good. Tell us a little bit about that design. So is this a randomized trial? Dr. Brendan Neuen: So CREDENCE was an event-driven randomized, double blind, placebo controlled, international trial. It was the first primary renal outcome trial of an SGLT-2 inhibitor, the primary results of which were reported in the New England journal in 2019. What this trial did, was it randomized participants, as I mentioned, with a GFR of greater than 30 and significant albuminuria and type two diabetes to either canagliflozin 100 milligrams or matching placebo in a one-to-one ratio with primary outcome overall of doubling of serum creatinine, kidney failure, cardiovascular or renal death. The trial was conducted in several, I think, 20 or 30 countries overall and enrolled at approximately 4,400 people, with participants followed for a median of about two and a half years. Dr. Greg Hundley: Excellent. So Brendan, tell us, what did you find? Dr. Brendan Neuen: So we found a couple of important findings with regards to blood pressure. Firstly, what we found was that canagliflozin reduced systolic blood pressure by about three and a half millimeters of mercury in the overall trial population. But most importantly, this blood pressure lowering effect was consistent across the number of blood pressure defined subgroups, including in people on multiple numbers of blood pressure lowering agents. So irrespective of the number of blood pressure lowering agents at baseline, and also irrespective of a history of apparent treatment-resistant hypertension at baseline, that was important. We also, secondly, found that the blood pressure lowering effective SGLT-2 inhibition was present very early at the first trial visit at three weeks. This effect was sustained over the duration of the trial. Dr. Brendan Neuen: Thirdly, we also found that canagliflozin reduced the risk of kidney failure and cardiovascular events, regardless of the number of blood pressure lowering agents at baseline and regardless of blood pressure, history of resistant hypertension. Finally, there is this often important question of how do these drugs reduce the risk of kidney failure and heart failure. So we did a mediation analysis, looking at to what extent the blood pressure lowering effect of this drug explains the treatment effect on these important outcomes. We found that only about less than 10% of the treatment effect on kidney failure and cardiovascular events was explained by blood pressure lowering. Dr. Greg Hundley: Very interesting and strong, powerful results. Well, now we're going to turn listeners to our associate editor, Dr. Wanpen Vongpatanasin. Wanpen, I know you see a lot of papers come across your desk at circulation, really focused on blood pressure and its lowering. What struck you about this paper, and then how do you put into context the results that Brendan just describe for us with all the other results that you see in new blood pressure lowering strategies? Dr. Wanpen Vongpatanasin: Yes, so I think this is very important study and add to a body of literature showing that the canagliflozin, like many SGLT-2 inhibitors, inducing significant lowering of blood pressure. If anything, because CREDENCE is not designed to be hypertension study the effects of blood pressure lowering my even be underestimated because the backup ground therapy allowed to be changed throughout the trial, depending on physician judgment. Also, I think the effects of many studies start to look at effects of SGLT-2 inhibitor on out of office blood pressure, like home blood pressure, or 24 blood pressure. Some even that we have published over the years, show more pronounced blood pressure lowering effects when measure outside the office. So I think that it is very interesting study but it could be not just only the drug that we use cardiovascular and renal outcome, but maybe a new class of antihypertensive medication that we could use for that purpose, although it has to be tested. Dr. Greg Hundley: Very nice. Well, Brendan, I want to turn back to you and then we'll come to Wanpen. Brendan, what do you think as a followup study to yours, what do you think is the next study that needs to be performed in this space? Dr. Brendan Neuen: Thanks, Greg. I think there's so much we still need to know about the blood pressure lowering effects of these drugs in people with advanced CKD. It would be very interesting to look at the DAPA-CKD trial, to look at the blood pressure lowering effects in people with advanced CKD not due to diabetes, so nondiabetic kidney disease. These patients also have a high burden of hypertension and whether or not these effects are also present in this population would also be important to know, and study patients with even more advanced kidney disease. That is being done in the EMPA-KIDNEY study with empagliflozin. Those results should be known in the next 12 to 24 months. Dr. Brendan Neuen: So, I'm studying this further in people with kidney disease. And also as Wanpen mentioned, looking at effects on blood pressure phenotype, you know, 24 hour blood pressure dipping status would also be important though, blood pressure variability, all those things can add to our understanding of the effect of these agents on blood pressure. Dr. Greg Hundley: Excellent. And Wanpen, do you have anything to add? Dr. Wanpen Vongpatanasin: Yes. I think one also very important study that helps someone with carrying in the future is in the CREDENCE, the people who are already treated with a mineralocorticoid receptor antagonist were excluded. So whether among resistant hypertension group, adding canagliflozin will be beneficial in those groups already treated MRA and lower cardiovascular outcome in already treated with MRA will be very interesting to see. Dr. Brendan Neuen: Yeah, I think that's a really important point to point out about the design of the CREDENCE trial, that patients who were on MRAs were excluded from the trial initially. This was due to early concerns that canagliflozin might increase the risk of hyperkalemia. I think that risk has now been put to bed in the other SGLT-2 inhibitor trials. We've got more data looking at the effects on serine potassium coming out soon, hopefully, but the other trials in which enroll more patients on MRAs, it will be very important to look at the blood pressure lowering effects in these populations. Dr. Greg Hundley: Excellent. Well, listeners, we've heard a great discussion today and we want to thank Brendan Neuen for bringing this wonderful science to us through circulation at the American Heart Association. We also want to thank our associate editor, Wanpen Vongpatanasin for being present today and helping us discuss how, in patients with type two diabetes and chronic kidney disease, describing that the blood pressure lowering effect of canagliflozin occurs early and appears sustained over the long term and therefore perhaps canagliflozin and can be used or considered as an adjunct blood pressure lowering medicine in addition to perhaps its protective effects on the kidney and other cardiovascular-related issues. Well now listeners, we've got another feature to get onto. So we're going to get to that second feature discussion right now. Dr. Greg Hundley: Well listeners, we are now turning to our second feature discussion and we're so fortunate today to have with us Dr. Saibal Kar from the Los Robles Regional Medical Center in Los Angeles, California, and our own associate editor, Dr. Mark Link from UT Southwestern in Dallas, Texas. Welcome gentlemen. Saibal, let's start with you. Could you describe for us the hypothesis that you wanted to test and what was your study population and your study design? Dr. Saibal Kar: Dr. Hundley, or if I could allow to call you Greg, thank you very much for asking me this question. The hypothesis was that we do know that the WATCHMAN device does prevent ischemic strokes. We do know that the first generation device has a few limitations. So there were some modifications made to the new WATCHMAN device, which is now called the WATCHMAN FLX. We thought that these changes should translate into better safety and better efficacy. So, that was the hypothesis of the study. The study population was patients with nonvalvular atrial fibrillation with a CHADS-VASc score of three or more, who had high risk of bleeding or patients who cannot take long-term anticoagulants. The study design was a single arm, prospective multicenter study with endpoints, which were based on performance goals from previous clinical trials. Dr. Greg Hundley: Excellent. Before we get to your results, Saibal how many patients and how many centers participated in your trial? Dr. Saibal Kar: So as the national principal investigator, I've never seen a study which was enrolled so fast. So the intended population was 400 patients in 29 centers and before half those centers could be activated, the study was over in four months. Dr. Greg Hundley: Congratulations. I think all of us that have ... especially in this pandemic era for recruiting so well, and tell us, what did you find? Dr. Saibal Kar: So what we found is that there were two endpoints, a safety endpoint and the efficacy endpoint. So the first thing that we found is that of the 400 patients, we could actually implant in 395 patients, device actually, which made the primary success rate over 98%. regarding the safety endpoint, we had a safety margin around 4% based on a performance score and set about 2.5, but the actual safety event rate was 0.5%, which was only two minor ischemic events, peri-procedural. There were no pericardial effusions in the first seven days, and there was no device embolizations at any time period, so that was the primary safety endpoint. So we were actually clearly safer than the first-generation device. Dr. Saibal Kar: When it comes to efficacy, it was an anatomical efficacy and we set the primary goal for the previous generation to be 99%. We've made a delta to make it about 97% effective, but we actually achieved an effective closure in 100% of patients. When I say effective closure, I mean that anyone with a peri device leak of less than five millimeters. Going into a little bit of granular detail, we actually found out that 90% of the patients actually had no leak at all. So we did at least achieve both the anatomical as well as the safety endpoints. Dr. Greg Hundley: Excellent. Well, listeners, we're now going to turn to our associate editor, Dr. Mark Link and Mark, I know you have many papers that pass through your hands. What attracted you to this paper. Then, these results really sound significant. Can you describe what impressed you also with the results of this study and how do they relate to other studies pertinent to implantation of devices in patients with atrial fibrillation? Dr. Mark Link: Yeah, we were interested in this paper at CERT because it's the next generation of the WATCHMAN. The numbers of patients that are being implanted with this device to prevent strokes is dramatically going up, but it's not a perfect device. So we were, as the EP community, very interested in the next generation device. We're obviously also interested in other competitors' device, but it's clear that the WATCHMAN is probably the world's leader in this time. So we knew that many of our people reading this magazine, reading the circulation, would want to see how the next generation turned out, was it really safer. That was really the primary goal of this study, it's really a safety study more than an efficacy study because the efficacy was defined by echo criteria, not by clinical criteria of stroke, which is the ultimate criteria. It was a well done study and the results came out more positive than I think even the investigators thought it was going to come out. So we liked it and that's why we did our best to get it published in circulation. Dr. Greg Hundley: Very good. So it sounds like great new innovation and very, very safe, especially relative perhaps to the first-generation device. So Saibal, can you tell us in just a few words, what do you think is the next study to be performed in this space? After you answer, Mark, we'll turn to you and basically ask the same question. Dr. Saibal Kar: Thank you very much, Greg. Transcatheter left atrial appendage closure has been approved by the FDA, specifically the WATCHMAN device, for patients who are candidates for long anticoagulation, but have limitations to long-term anticoagulation and therefore not for all-comers and there's a reason for that. The time has now come to actually evaluate this device for all-comers. That means all patients with nonvalvular atrial fibrillations who are suitable for anticoagulants. Therefore, the next best study is the CHAMPION trial. This study is going to be a randomized trial of the WATCHMAN FLX versus NOACs, or more correctly DOACs, in all-comers, patients with nonvalvular atrial fibrillation who require long-term anticoagulants. It's a 3,000 patients clinical trial with a one-to-one randomization to WATCHMAN FLX or the continuation of DOACs and the primary endpoints will be estimated at three years with a follow-up up to five years. Our goal is to show that we are non-inferior in comparison to stroke and death, and superior respect to long-term bleeding. Dr. Greg Hundley: Very good, and Mark? Dr. Mark Link: Yeah, I agree. The CHAMPION trial is the obvious next trial that everyone wants to see the results of, comparing this device to DOACs. Another trial or data I'd like to see is the immediate post-procedural anticoagulation. It's still an area that we don't have enough data to know how to treat these patients. Traditionally, they've been treated with warfarin and anti-platelet agents, but many of the patients getting this WATCHMAN have a relative contraindication to anticoagulation. So I'd like to see some data on shorter term duration of anticoagulation post-implant. Dr. Greg Hundley: Very good. Well listeners, we've had a wonderful discussion here and we want to thank the lead author, Dr. Saibal Kar and also our own associate editor, Dr. Mark Link, for really providing us with new information that this left atrial appendage closure device met the primary safety outcome in 99.5% of all of those implanted within seven days, what a remarkable finding. So, on behalf of Carolyn and myself, we want to wish you a great week and we will catch you next week on the Run. This program is copyright of the American Heart Association, 2021.  

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.31.363515v1?rss=1 Authors: Hamano, F., Matoba, K., Hashidate, T., Suzuki, T., Miura, K., Hishikawa, D., Harayama, T., Yuki, K., Kita, Y., Noda, N. N., Shimizu, T., Shindou, H. Abstract: Platelet-activating factor (PAF) is a potent proinflammatory phospholipid mediator that elicits various cellular functions and promotes several pathological conditions, including anaphylaxis and neuropathic pain. PAF is biosynthesized by two types of lyso-PAF acetyltransferases: lysophosphatidylcholine acyltransferase 1 (LPCAT1) and LPCAT2, which are constitutive and inducible forms of lyso-PAF acetyltransferase, respectively. Because LPCAT2 mainly produces PAF under inflammatory conditions, understanding the structure of LPCAT2 is important for developing specific drugs against PAF-related inflammatory diseases. Although the structure of LPCAT2 has not been determined, the crystal structure was reported for Thermotoga maritimaPlsC, an enzyme in the same enzyme family as LPCAT2. In this study, we identified residues in mouse LPCAT2 essential for its enzymatic activity and a potential acyl-coenzyme A (CoA)-binding pocket, based on homology modeling of mouse LPCAT2 with PlsC. We also found that Ala115 of mouse LPCAT2 was important for acyl-CoA selectivity. In conclusion, these results predict the structure of mouse LPCAT2. Our findings have implications for the future development of new drugs against PAF-related diseases. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.10.30.362673v1?rss=1 Authors: El-Baz, H., Elazzazy, A. M., Saleh, T. S., Dourou, M., Mahyoub, J. A., Baeshen, M. N., Madian, H. R., Aggelis, G. Abstract: Sugar fatty acid esters, especially glucose fatty acid esters (GEs), have broad applications in food, cosmetic and pharmaceutical industries. In this research the fatty acid moieties derived from polyunsaturated fatty acid containing single cell oils (SCOs), i.e. those produced from Cunninghamella echinulata , Umbelopsis isabellina and Nannochloropsis gaditana as well as from olive oil and an eicosapentaenoic acid (EPA) concentrate were converted into GEs by enzymatic synthesis, using lipases as biocatalysts. The GE synthesis was monitored using thin-layer chromatography, FT-IR and in situ NMR. It was found that GE synthesis carried out using immobilized Candida antarctica B lipase was very effective reaching high yields, near to 100%. It was shown that EPA-GEs were very effective against several pathogenic bacteria and their activity can be attributed to their high EPA content. Furthermore, C. echinulata-GEs were more effective against pathogens comparing to U. isabellina-GEs, probably due to the presence of gamma linolenic acid (GLA) in the lipids of C. echinulate, which is known for its antimicrobial activity, in higher concentrations. C. echinulata-GEs also showed a strong insecticidal activity against Aedes aegypti larvae, followed by EPA-GEs, olive oil-GEs, and N. gaditana-GEs. All synthesized GEs induced apoptosis of the SKOV-3 ovarian cancer cell line, with the apoptotic rate increasing significantly after 48 h. A higher percentage of apoptosis was observed in the cells treated with EPA-GEs, followed by C. echinulata-GEs, U. isabellina-GEs and olive oil-GEs. We conclude that SCOs can be used in the synthesis of GEs with interesting biological properties. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.13.295113v1?rss=1 Authors: El-Baz, H. A., Elazzazy, A. M., Saleh, T. S., Dritsas, P., Mahyoub, J. A., Baeshen, M. N., Madian, H. R., Alkhaled, M., Aggelis, G. Abstract: Fatty acid amides (FAAs) are of great interest due to their broad industrial applications. They can be synthesized enzymatically with many advantages over chemical synthesis. In this study, the fatty acid moieties of lipids of Cunninghamella echinulata ATHUM 4411, Umbelopsis isabellina ATHUM 2935, Nannochloropsis gaditana CCAP 849/5, Olive oil and an eicosapentaenoic acid (EPA) concentrate were converted into their fatty acid methyl esters and used in the FAA (i.e. ethylene diamine amides) enzymatic synthesis, using lipases as biocatalysts. The FAA synthesis, monitored using in situ NMR, FT-IR and thin-layer chromatography, was catalyzed efficiently by the immobilized Candida rugosa lipase. The synthesized FAAs exhibited a significant antimicrobial activity, especially those containing oleic acid in high proportions (i.e. derived from Olive oil and U. isabellina oil), against several human pathogenic microorganisms, insecticidal activity against yellow fever mosquito, especially those of C. echinulata containing gamma linolenic acid, and anti-cancer properties against SKOV-3 ovarian cancer cell line, especially those containing EPA in their structures (i.e. EPA concentrate and N. gaditana oil). We conclude that FAAs can be efficiently synthesized using microbial oils of different fatty acid composition and used in specific biological applications. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.09.11.294397v1?rss=1 Authors: Shimell, J. J., Globa, A. K., Sepers, M. D., Wild, A. R., Matin, N., Raymond, L. A., Bamji, S. X. Abstract: Palmitoylation is the most common post-translational lipid modification in the brain. However, the role of palmitoylation and palmitoylating enzymes in the nervous system remains elusive. One of these enzymes, Zdhhc5, has previously been shown to regulate synapse plasticity. Here, we report that Zdhhc5 is also essential for the formation of excitatory, but not inhibitory synapses both in vitro and in vivo. We demonstrate in vitro that this is dependent on Zdhhc5s enzymatic activity, its localization at the plasma membrane, and its C-terminal domain which has been shown to be truncated in a patient with schizophrenia. Loss of Zdhhc5 in mice results in a decrease in the density of excitatory hippocampal synapses accompanied by alterations in membrane capacitance and synaptic currents, consistent with an overall decrease in spine number and silent synapses. These findings reveal an important role for Zdhhc5 in the formation and/or maintenance of excitatory synapses. Copy rights belong to original authors. Visit the link for more info

Hear from the experts in our conversations on a type of fatty acid oxidation disorder: VLCAD. We cover VLCAD diagnosis, new treatment options, and how to connect with the VLCAD community. Experts in this episode include: *Erika Beckman, MS: Genetic Counselor in Seattle, WA. *J. Daniel Sharer, PhD: Director of the Biochemical Genetics Laboratory at UAB. *Deb Lee Gould, MEd: Director of the FOD Family Support Group. More resources and information for you: raredisease.com/vlcad

 Tous les matins en direct de Tsugiradio, on se fait 20min ensemble pour parler musique autour d'un album, un artiste, une compilation, une bande originale. Cet été, on part de façon hebdomadaire, dans un pays pour découvrir ou redécouvrir de la musique et des artistes.   

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.08.07.241471v1?rss=1 Authors: Chang, T.-Y., Chang, C. C., Rogers, M. A. Abstract: Niemann-Pick type C (NPC) is a neurological disorder with no cure. NPC proteins deliver cholesterol from endosomes to other compartments including trans-Golgi network (TGN) and endoplasmic reticulum (ER). Acyl-coenzyme A:cholesterol acyltransferase 1 (ACAT1) is a resident ER enzyme that converts cholesterol to cholesteryl esters for storage. Here, we report the surprising finding that in a mutant Npc1 mice, Acat1-deficiency delayed the onset of weight loss and declining motor skill, prolonged lifespan, delayed Purkinje neuron death, and improved hepatosplenic pathology. Furthermore, syntaxin 6, a cholesterol-binding t-SNARE normally localized to TGN, is mislocalized in mutant NPC cells. However, upon ACAT1 inhibition this mislocalization is corrected, and increase the level of a few proteins further downstream. Our results imply that ACAT1 inhibition diverts a cholesterol storage pool in a way that replenished the low cholesterol level in NPC-deficient TGN. Taking together, we identify ACAT1 inhibition as a potential therapeutic target for NPC treatment. Copy rights belong to original authors. Visit the link for more info

Link to bioRxiv paper: http://biorxiv.org/cgi/content/short/2020.07.30.229468v1?rss=1 Authors: Trefely, S., Huber, K., Liu, J., Singh, J., Doan, M., Lovell, C. D., Noji, M., von Krusenstiern, E., Jiang, H., Bostwick, A., Izzo, L., Zhao, S., Bedi, K. C., Rame, J. E., Bogner-Strauss, J. G., Mesaros, C., Wellen, K. E., Snyder, N. W. Abstract: Metabolism is highly compartmentalized within cells, and the sub-cellular distribution of metabolites determines their use. Quantitative sub-cellular metabolomic measurements can yield crucial insights into the roles of metabolites in cellular processes. Yet, these analyses are subject to multiple confounding factors in sample preparation. We developed Stable Isotope Labeling of Essential nutrients in cell Culture - Sub-cellular Fractionation (SILEC-SF), which uses rigorous internal standard controls that are present throughout fractionation and processing to quantify metabolites in sub-cellular compartments by liquid chromatography-mass spectrometry (LC-MS). Focusing on the analysis of acyl-Coenzyme A thioester metabolites (acyl-CoAs), SILEC-SF was tested in a range of sample types from cell lines to mouse and human tissues. Its utility was further validated by analysis of mitochondrial versus cytosolic acyl-CoAs in the well-defined compartmentalized metabolic response to hypoxia. We then applied the method to investigate metabolic responses in the cytosol and nucleus. Within the cytosol, we found that the mevalonate pathway intermediate 3-Hydroxy-3-methylglutaryl-CoA (HMG-CoA) is exquisitely sensitive to acetyl-CoA supply. The nucleus has been an exceptionally challenging compartment in which to quantify metabolites, due in part to its permeability. We applied the SILEC-SF method to nuclei, identifying that the nuclear acyl-CoA profile is distinct from the cytosolic compartment, with notable nuclear enrichment of propionyl-CoA. Altogether, we present the SILEC-SF method as a flexible approach for quantitative sub-cellular metabolic analyses. Copy rights belong to original authors. Visit the link for more info

This month on Episode 14 of the Discover CircRes podcast, host Cindy St. Hilaire highlights four featured articles from the July 3 and July 17 issues of Circulation Research. This episode also features an in-depth conversation with Dr. Brenda Ogle and Drs. Molly Kupfer and Wei-Han Lin regarding their study, In Situ Expansion, Differentiation and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid.     Article highlights:   Wei, et al. Palmitoylation Cycling and Endothelial Maturity   van Ouwerkerk, et al. Functional Variant Elements in Atrial Fibrillation Models   Ibarrola, et al.  Aldosterone in MVP   Sharma, et al. Atherosclerosis Regression Requires Regulatory T Cells   Cynthia St. Hilaire: Hi, welcome to Discover CircRes, the podcast of the American Heart Association's Journal, Circulation Research. I'm your host, Dr. Cindy St. Hilaire, from the Vascular Medicine Institute at the University of Pittsburgh. Today I'm going to share with you four articles selected from our July issues of Circulation Research, as well as have a discussion with Dr. Brenda Ogle and the first authors, Molly Kupfer and Wei-Han Lin, regarding their study, In Situ Expansion, Differentiation and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid. So first, the highlights. The first article I want to share with you is titled, "Endothelial Palmitoylation Cycling Coordinates Vessel Remodeling in Peripheral Artery Disease." The first author is Xiaochao Wei, and the corresponding author is Clay Semenkovich from Washington University, St. Louis. Peripheral artery disease, or PAD for short, is a vascular occlusive disease of the lower extremities. It affects more than 2 million individuals globally, and its prevalence is ever increasing as our population ages. While statin therapy can be useful for combating coronary artery disease in peripheral artery disease patients, it does not prevent or reduce PAD patients' rates of lower extremity amputation. So looking to gain insights into the mechanisms underlying PAD, this team focused on the findings that circulating fibronectin and the dietary saturated fatty acid, palmitate, are associated with peripheral artery disease. They found this interesting as lipid modification proteins has been implicated in infections, premature aging, cancer and diabetes. One such protein modification is palmitoylation, which is the formation of a thioester bond between palmitate sand cysteine. Acyl-protein thioesterase 1, or APT1, is a depalmitoylase enzyme, which removes the fatty acid palmitate from protein. Using mouse models with inactivated endothelial APT1, as well as cell systems in arterial samples from humans with end stage peripheral artery disease, they tested whether deficiencies in palmitoylation cycling promotes endothelial instability, which is a hallmark of chronic arterial occlusive diseases. They discovered that as many as 10% of all proteins are palmitoylated. They found deficiency of APT1 in endothelial cells disrupts vascular homeostasis, in part by altering the intracellular trafficking of the small GTPase R-Ras. Impaired R-Ras membrane trafficking was rescued by modifying the palmitoylated R-Ras molecule to promote dissociation from membranes. These observations identify palmitoylation cycling as a potential therapeutic target in the treatment of peripheral vascular disease. The second article I want to highlight is titled, "Identification of Functional Variant Enhancers Associated with Atrial Fibrillation." The first author is Antoinette van Ouwerkerk, and the corresponding authors are Antoine de Vries and Vincent Christoffels, And they're from UMC Amsterdam. As we heard in our podcast last month with our interview with Dr. David McManus, atrial fibrillation, or AFib, is the most common form of arrhythmia, and is a major risk for heart failure, dementia, and stroke, and sudden death. Genome-wide association studies have revealed more than a hundred genetic loci linked to this condition, and many of these loci are found in non-coding regions, which are enriched for transcription factor binding sites and epigenetic modification sites, suggesting that these loci could potentially have gene regulatory roles. To test this idea, they use the method called self-transcribing active regulatory region sequencing, or STARR-seq, which is a method used to identify the sequences that act as transcriptional enhancers in a direct quantitative and genome-wide manner. They use STARR-seq to screen 12 of the strongest AFib linked regions of the genome, which contain more than 1600 individual aphid linked genetic variance, and they did this in cultured rat atrial monocytes. From this screen, they found approximately 400 regulatory elements, of which 24 exhibited variant-specific differences in regulatory activity. For one of these elements, upstream of the gene HCN4, deletion of the orthologous element in mice caused diminished transcriptional activity of the gene. Moreover, these variant-containing mice had brachycardia and sinus node dysfunction, both components of arrhythmia. This proof of principle study confirms that such a regulatory element screen could provide insight into the consequences of variants associated with AFib, or for that matter, many other diseases. The next article I want to share with you is titled, "A New Role for the Aldosterone/Mineralocorticoid Receptor Pathway in the Development of Mitral Valve Prolapse." The first author is Jaime Ibarrola, and the corresponding author is Natalia López-Andrés, and their work was completed at Sanitaria de Navarra in Pamplona, Spain. Mitral valve prolapse is a condition where blood leaks back into the left atrium of the heart, and it is the most common form of heart valve defects. The underlying pathology includes an overabundance of cells in the valve leaflet, so-called valve interstitial cells, or VICs. These activated VICs overproduce extracellular matrix protein, and the combination of increased numbers of VICs and increased amounts of extracellular matrix proteins contributes to the impairment of the structural integrity of the valve leaflet. The increase in VICs is due to excess proliferation, but also transformation of valve endothelial cells, so the cells that line the leaflet, valve endothelial cells, into mesenchymal like VICs. As a driver of endothelial to mesenchymal transition, aldosterone was suspected to play a role. Aldoesterone increased expression of VIC activation markers in cultured valve endothelial cells and increased production of certain extracellular matrix protein components. Spironolactone, an aldosterone inhibitor, prevented these effects, and importantly, prevented valve remodeling in a mouse model of mitral valve prolapse. The team showed that valve tissue from mitral valve prolapse patients taking aldosterone receptor inhibitors displayed less evidence of VIC activation and lower production of disease-regulated extracellular matrix components, than those not taking the drugs. These exciting results suggest aldosterone antagonists, already used for certain patients with heart failure or high blood pressure, may also benefit those with mitral valve prolapse. The last article I want to share before we switch to our interview, is titled, " Regulatory T Cells License Macrophage Pro-Resolving Functions During Atherosclerosis Regression." The first author is Monika Sharma, and the corresponding author is Kathryn Moore, and they're from New York University. Atherosclerosis is a chronic inflammatory condition characterized by the buildup of fatty deposits in the artery walls, and monocytes and macrophages can infiltrate into these fatty deposits and contribute to the formation of plaque. Cholesterol-lowering drugs, like statins, promote the reduction of low-density lipoproteins in the blood, which can help to slow plaque growth, but they do not reverse disease progression. One possibility for changing the course of the disease is to develop therapies that can reduce plaque inflammation, and therefore, progression. With that goal in mind, this team investigated how the immunosuppressive activity of regulatory T cells, or Tregs, may influence the functions of plaque monocytes and macrophages. Using mouse models in which the disease can be reversed through aggressive lipid lowering, they found that depletion of the Treg population caused an increase in the numbers of monocytes and macrophages in the plaques, and resulted in poorer plaque regression. Indeed, these monocytes and macrophages proliferated more, remained in the plaques longer, and were less likely to adopt an anti-inflammatory pro-plaque resolving M2-like phenotype than plaque macrophages in mice with normal Treg numbers. Together, these results highlight the importance of Tregs for promoting plaque regression, and suggest future therapies aimed at boosting these cells, or indeed, M2 macrophages may enable atherosclerosis remission. Okay, so now we're going to switch over to the interview portion of our podcast. I have with me Dr. Brenda Ogle, who is a professor of biomedical engineering, and first authors Molly Kupfer and Wei-Han Lin, and they're from the University of Minnesota. And today we're going to be discussing their manuscript titled, "In Situ Expansion, Differentiation and Electromechanical Coupling of Human Cardiac Muscle in a 3D Bioprinted, Chambered Organoid." So thank you all for joining me today.   Brenda Ogle: Thank you. Molly Kupfer: Thanks for having us. Wei-Han Lin: Thank you. Cynthia St. Hilaire: Great. I'm glad we can all do this remotely and nice and safe for COVID. So Dr. Ogle, you're the PI of the group, but Molly and Wei-Han, what stages of career are you at? Molly Kupfer: I just recently completed my PhD, so this work is sort of the culmination of that. Cynthia St. Hilaire: Oh, congratulations! Molly Kupfer: Yeah. Thank you. Cynthia St. Hilaire: Well done. Circ Research is a great thesis publication. Congratulations. Molly Kupfer: Thank you. Cynthia St. Hilaire: Wei-Han, how about you? Wei-Han Lin: So I'm a BME PhD student at the University of Minnesota. And I got my master degree in chemical engineering, but in Taiwan, and now I'm working with professor Brenda Ogle on cardiac tissue engineering stuff. Cynthia St. Hilaire: Excellent. So this is a beautiful paper. It's stunning. It has all sorts of wonderful parts, biological, biomechanical, great imaging, and essentially you created a 3D bio-ink that can be used to print and make a living pump, kind of a heart in a dish. And it's something that you're calling this human chambered muscle pump, or ChaMP, which I think is a great name. Can you please describe exactly what that is and why did you want to go about trying to make it? Molly Kupfer: Yeah, it might help if I give a little bit of context to this. So since the beginning, one of the central questions that the lab has been exploring is how do the cells of the heart interact with their environment, or the extracellular matrix, as we call it? We know that these interactions that occur at the cellular level are absolutely critical for cardiac function, both at the tissue and the organ level. And based on years of research studying how the extracellular environment modulates cellular function, we have now sought to apply what we've learned in order to engineer functional human cardiac tissues by recapitulating those very critical interactions in vitro. And actually, back in 2017, we published another study in Circulation Research, where we generated these contractile patches of cardiac tissue using a form of light-based 3D printing that allowed us to fabricate scaffolds with really high resolution micron-level features that were distributed in a way that mimics the native extracellular environment. And what we found is that by organizing the extracellular matrix in that way, we enabled the cells to organize themselves in the scaffold and form connections with each other and with the scaffold itself. And this was critical to achieving synchronous electromechanical function of the tissue as a whole. But these were very small millimeter scale tissues, and so for this new study, we sought to create something on a larger scale where you could incorporate some new geometric features such as chambers and the capacity for perfusion. And as you mentioned, using our knowledge of the interactions between cells and the extracellular matrix, we developed this unique bio-ink that could be used as a vehicle to 3D print these centimeter scale chambered tissue structures that are based on the geometry of the human heart. And so the tissues that resulted from this, the human chambered muscle pumps, or hChaMPs, exhibit thick, contiguous muscularization. They demonstrate electrical connectivity and pump function. And notably, this is the first time that this level of function and muscularization has been achieved in an engineered cardiac tissue of this level of geometric complexity. Cynthia St. Hilaire: So can you maybe talk a little bit about what do you mean by an ink, exactly? Is it actually printed? Is this like a printer that I could buy on Amazon? Obviously there's a huge biological component, but what are the actual technical things that you had to develop to make this chamber happen?  Molly Kupfer: Yes. So we did use an extrusion-based 3D printing, which is similar to probably what people normally think about with 3D printing. Traditionally, it's been with plastics. In this case, we're printing with a bio-ink, which is essentially a formulation of proteins and other materials that we encapsulate the cells in, and then after that, we extrude it from a nozzle in a specific formulation or shape in order to create the structure. Cynthia St. Hilaire: So that's interesting. So in this mix, the cells are already in there as opposed to, I guess, some other things that people tend to call scaffolds where you kind of print that and then seed it?  Molly Kupfer: Mm-hmm (affirmative). And in the example of the paper I discussed from 2017, that was an example where we printed a scaffold and put the cells in. But in this case, for such a large and complex structure, we actually mix the cells in prior to printing, and then we create the structure. Cynthia St. Hilaire: Wow. What's the timeframe of that? Like the cells, you got to digest them and mix things up and then print it. The cells, are they happy?  Molly Kupfer: Yeah, that's a good question. So the actual printing process is quite fast, maybe a couple of minutes for this particular scale. We have to prepare, culture, the cells in advance and we're working with human-induced, pluripotent stem cells, so it takes time to grow them up, and then yes, we do detach them and singularize them, and we then mix them with the components. But overall, the actual printing process is relatively quick. Then it's a matter of maintaining the structure and culturing it and doing the differentiation as we did. And that takes weeks to do over time. But the actual process of making it, initially, is quite quick. Brenda Ogle: Challenging thing about this project was the fact that mature cardiac muscle does not transfer well. Meaning when you move it from a dish to an ink and then print it and ask it to start beating again, it doesn't typically happen. And that is because cardiomyocytes don't proliferate well, or make more of each other, and they also don't move well, or migrate. And so the premise on which most of this paper relies is on printing the stem cells first, letting them expand, sort of like they do with development, and then encouraging them to specify into cardiac cell types. Cynthia St. Hilaire: What's the bigger good that can come out of this? Why do we want to be able to do this in vitro, or even ex vivo heart in a dish? Brenda Ogle: The value is pretty tremendous because, suddenly we have a human model system in which we can perfuse volume, so volume can go in and come out, in which the cells experience those volume metric and fluid-induced forces that we haven't been able to study human cells in this way ever before. In the context of human disease, this is the first time we'll be able to look at onset of a particular disease, what was happening with onset, and then progression. And I think that is what is going to transform this field. Cynthia St. Hilaire: So what was the first one like? I'm thinking back to my graduate school and also my postdoc where I was involved in some disease discovery and I have a very vivid memory of the Western blot that proved the mutation that we found. And I literally ran down the hall holding the film. I'm imagining, maybe I'm projecting too much, but what was seeing that first one beat like? Molly Kupfer: You're not projecting. I feel like that well describes my experience. We had some early experiences where we would start to see beating areas under the microscope, but I think the moment, for me, was, I think there was one night I was working in the lab and I had some plates out, I was looking at stuff under the microscope going through just the mundane lab tasks, and I think I sort of saw it at the corner of my eye in the dish, something was moving. And that was the first time. Like I had watched parts of these things beat under a microscope all the time. I spent years looking at cardiomyocytes under a microscope, but that was the first time, for these hChaMPs, where I could actually see it moving just by my eye. Cynthia St. Hilaire: Wow. Molly Kupfer: And that was a really cool moment. Wei-Han Lin: Yeah. I was mostly working on the printing side, so the first time I realized the heart started beating, it's more like a shock to me, because I'm always printing the models or just the mold. But then really seeing those cells, or the whole structure, start to beat, was quite amazing.   Cynthia St. Hilaire: Could you please tell me a bit about the 3D printing aspect of it? Is it like a shell like the outside of a balloon, or does it have an interior structure that helps dictates where the cell go? Can you explain what the printing is? Wei-Han Lin: So the structure we are printing is derived from MRI image stacks on a real human heart. And the image stack was segmented and reduce the size by 10 times, and then we convert the stack into the STL file, which is the standard operating format. And then we modify the model a little bit to make it into two chambers and with two vessels, and two connected chambers with two openings. And this is the heart we are using for the study. Cynthia St. Hilaire: Got it. So it's got kind of the big picture items of the heart. It's got two tubes going in and it's got two chambers and the fluid can flow between all of those aspects in a specific flow pattern. Wei-Han Lin: Exactly. Cynthia St. Hilaire: You said you have to differentiate them in a dish and you're adding different factors to do that. Do the cells like being in that scaffold, or do they want to seep out of that structure or is there something about the bio-ink that they're happy there? Molly Kupfer: You know, I think this bio-ink was, to a certain extent, optimized or designed such that the cells would be able to continue to attach and grow and remodel. So basically, for the most part, these components are biological materials. Some of them are just proteins. Some of them are proteins that have been modified with photo cross-linkable elements, but they still have these moieties that the cells can attach to. And over time we do see some remodeling and some extracellular matrix gets degraded and some gets deposited. Cynthia St. Hilaire: So have you gone to the next steps of something like single cell seq and trying to see what kind of cells you're getting in this? Or even maybe inputting different, the scaffold is getting one differentiation protocol, but are you possibly able to prime IPS cells such that they're maybe halfway to a vascular cell, or halfway to a cardiomyocyte cell, and then put them in the bio-ink? Brenda Ogle: That's a really interesting idea. I'm going to take that one. Cynthia St. Hilaire: Give me an acknowledgment. Brenda Ogle: So we've been thinking about that, the context of if expansion of IPS cells is the best way, for many cell types, how do we get multiple cell types and organize them? And you can imagine even just printing in specific areas, different cell types. Cynthia St. Hilaire: Oh, sure. Brenda Ogle: But the other thing we've thought about is delivering differentiation factor spatially. So almost printing a cell, but then printing that. depot of a factor, in the area that we wanted or in an arrangement that we want, and then releasing it when we want. And it's challenging for stem cell differentiation, because you really need no release, and then basically zero order release for two or three days, and then no release again. Cynthia St. Hilaire: Right. Brenda Ogle: So it's a challenging drug delivery problem, but we've been thinking a lot about it. Now priming the cells beforehand is another interesting approach. Cynthia St. Hilaire: Well, that's wonderful. I just want to congratulate you all again. Brenda Ogle: Thank you so much for having us. Cynthia St. Hilaire: Yeah, thank you so much. Wei-Han Lin: Thank you so much. Cynthia St. Hilaire:  That's it for our highlights from the July issues of Circulation Research. Thank you so much for listening. Please check out the Circulation Research Facebook page and follow us on Twitter and on Instagram with the handle @CircRes and #discovercircres. Thank you to our guests, Dr. Brenda Ogle, Dr. Molly Kupfer and Wei-Han Lin. This podcast is produced by Rebecca McTavish and Ishara Ratnayake, edited by Melissa Stoner and supported by the editorial team of Circulation Research. Some of the copy texts for highlighted articles was provided by Ruth Williams. I'm your host Dr. Cindy St. Hilaire, and this is Discover CircRes, you're on the go source for the most up-to-date and exciting discoveries in basic cardiovascular research.  

Les membres du groupe ACYL, représenté par Amine (chanteur et guitariste), Abderrahmane (guitare) et Aghilas (le nouveau batteur), étaient les invités du ZanZanA Live Streaming Show, le mercredi 01 juillet 2020. Deux heures durant, ils ont répondu aux questions des auditeurs et de Karim Benamor. Divers sujets ont été abordés que vous pourrez découvrir en visionnant le replay de l'interview dans les liens du Streaming que voici : - FaceBook : https://www.facebook.com/watch/?v=279502043166534 - YouTube : https://youtu.be/_mkcPsD3xNI #Acyl #ZanZanA #Metal

Les membres du groupe ACYL, représenté par Amine (chanteur et guitariste), Abderrahmane (guitare) et Aghilas (le nouveau batteur), étaient les invités du ZanZanA Live Streaming Show, le mercredi 01 juillet 2020. Deux heures durant, ils ont répondu aux questions des auditeurs et de Karim Benamor. Divers sujets ont été abordés que vous pourrez découvrir en visionnant le replay de l'interview dans les liens du Streaming que voici : - FaceBook : https://www.facebook.com/watch/?v=279502043166534 - YouTube : https://youtu.be/_mkcPsD3xNI #Acyl #ZanZanA #Metal

Les membres du groupe ACYL, représenté par Amine (chanteur et guitariste), Abderrahmane (guitare) et Aghilas (le nouveau batteur), étaient les invités du ZanZanA Live Streaming Show, le mercredi 01 juillet 2020. Deux heures durant, ils ont répondu aux questions des auditeurs et de Karim Benamor. Divers sujets ont été abordés que vous pourrez découvrir en visionnant le replay de l'interview dans les liens du Streaming que voici : - FaceBook : https://www.facebook.com/watch/?v=279502043166534 - YouTube : https://youtu.be/_mkcPsD3xNI #Acyl #ZanZanA #Metal

Lang biochem - Medium-Chain Acyl-CoA Dehydrogenase deficiency

References:1. Penniston KL, Tanumihardjo SA. The acute and chronic toxic effects of vitamin A. Am J Clin Nutr. 2006;83(2):191-201.2. Hathcock JN, Hattan DG, Jenkins MY, McDonald JT, Sundaresan PR, Wilkening VL. Evaluation of vitamin A toxicity. The American journal of clinical nutrition. 1990;52(2):183-202.3. Bhattacharya S, Singh A. Phasing out of the Universal Mega Dose of Vitamin-A Prophylaxis to Avoid Toxicity. AIMS public health. 2017;4(1):38-46.4. Blaner WS, Li Y, Brun PJ, Yuen JJ, Lee SA, Clugston RD. Vitamin A Absorption, Storage and Mobilization. Sub-cellular biochemistry. 2016;81:95-125.5. de Oliveira MR. Vitamin A and Retinoids as Mitochondrial Toxicants. Oxid Med Cell Longev. 2015;2015:140267.6. Russell RM. The vitamin A spectrum: from deficiency to toxicity. The American journal of clinical nutrition. 2000;71(4):878-84.7. Senoo H, Imai K, Mezaki Y, Miura M, Morii M, Fujiwara M, et al. Accumulation of vitamin A in the hepatic stellate cell of arctic top predators. Anat Rec (Hoboken). 2012;295(10):1660-8.8. Ball MD, Furr HC, Olson JA. Acyl coenzyme A:retinol acyltransferase activity and the vitamin A content of polar bear (Ursus maritimus) liver. Comp Biochem Physiol B. 1986;84(4):513-7.9. O'Donnell J. Polar hysteria: an expression of hypervitaminosis A. Am J Ther. 2004;11(6):507-16.

Dr Carolyn Lam:                Welcome to Circulation on the Run, your weekly podcast summery and backstage pass to the journal and it's editors. We're your co-hosts, I'm Doctor Carolyn Lam, Associate Editor from the National Heart Center and Duke National University of Singapore. Dr Gregory Hundley:       And I'm Doctor Greg Hundley, Associate editor for Circulation and Director of the Pauley Heart Center at VCU of Health in Richmond, Virginia. Well Carolyn, in the second half of our feature we're going to discuss a randomized clinical trial in lower risked surgical patients related to, the five year clinical echocardiographic outcomes from aortic valve intervention. So Carolyn, do you want to go first this time and discuss on of your favorite papers? Dr Carolyn Lam:                Absolutely! So, are Cardiac Troponin T and I equivalent measures of cardiovascular risk in the general population? Well that's the question Doctor Paul Welsh and colleagues from University of Glasgow aimed to look at. They wanted to compare and contrast the associations of Cardiac Troponin T and Cardiac Troponin I with cardiovascular disease and non-cardiovascular disease outcomes, and also determine their genetic determinants in a genome wide association study involving more than nineteen-thousand, five hundred individuals in generation Scotland, Scottish family health study. Dr Gregory Hundley:       How about that. So this is kind of interesting. So most of us kind of use these two chests interchangeably Carolyn, and I think, I guess we'd consider them to be almost equivalent. So are you going to tell us that they are the same? Dr Carolyn Lam:                Ah-hah! So this is what the authors found. Both Cardiac Troponins T and I were strongly associated with cardiovascular risk, however, Cardiac Troponin I but not T was associated with both myocardial infarction and coronary heart disease. Both Cardiac Troponins I and T had strong associations with cardiovascular death and heart failure, however, Cardiac Troponin T, but not I was associated with non-cardiovascular disease death. They also identified five genetic loci in fifty-three individuals snips that had GWAS significant associations with Cardiac Troponin I and a different set of four loci of four snips for Cardiac Troponin T.                                                 So, the upstream genetic causes of low-grade elevations of Cardiac Troponins I and Cardiac Troponin T appear to be distinct and their associations with outcomes also differ. Elevations of Cardiac Troponin I are more strongly associated with some cardiovascular disease outcomes whereas Cardiac Troponin T, is more strongly associated with the risk of non-cardiovascular disease death. These findings can help inform selection of an optimal Troponin essay for future clinical care and research in these settings. Dr Gregory Hundley:       Very good! So, does sound like there could be a little bit of a difference, depending upon what outcome you're looking for. So, Carolyn I'm going to discuss a paper from Doctor Alison Wright and colleagues at the University of Manchester, and it involves cardiovascular risk and risk factor management in type two diabetes.                                                 So in this retrospective cohort study, using the clinical practice research data link, linked to hospital and death records for people in England, investigators identified 79,985 patients with incident type two diabetes, between the years 2006 and 2013, matched to three 386,547 patients without diabetes, and sex-stratified Cox models were used to assess cardiovascular risk. Dr Carolyn Lam:                Oh I'm dying to know, what did they find? Dr Gregory Hundley:       Well compared to women without type two diabetes mellitus, women with type two diabetes mellitus had a higher cardiovascular event risk than the adjusted hazard ratios 1.2, with similar corresponding data in men, so their hazard ratio is 1.1. And that lead to a nonsignificant relative risk in women with a risk ration of 1.07, however, some important sex differences in the management of risk factors were observed. Compared to men with type two diabetes, women with type two diabetes were more likely to be obese, hypertensive, and have hypercholesterolemia but were less likely to be described lipid lowering medication, ace inhibitors, especially if they had cardiovascular disease. So Carolyn, compared to men developing type two diabetes mellitus, women with type two diabetes mellitus do not have a significantly higher relative increase in cardiovascular risk, but, ongoing sex disparities in prescribing should prompt heightened efforts to improve the standard and equity of diabetes care in women as compared to men. Dr Carolyn Lam:                Nice Greg. Important message. My next one has an important message too. Now it goes to the pediatric population now. We know that brain injury, impaired brain growth, and long term neuro development problems are common in children with transposition of the great arteries. Now does the age at arterial switch operation predict these neuro developmental outcomes in infants with transposition of the great arteries or TGA?                                                 Well Doctor Mike Seed from Hospital for Sick Children in Toronto, Canada and colleges addressed this question by imaging the brains of 45 infants with TGA, undergoing surgical repair, pre and post operatively using MRI. Their main finding was that surgery beyond two weeks of age is associated with impaired brain growth and slower language development in infants with TGA. Dr Gregory Hundley:       Wow Carolyn, this seems like, this could have really important clinical implications for the management of these patients. Dr Carolyn Lam:                Yeah, indeed. Expediting surgical repair could be neuro protective in newborns with Transposition. While the mechanisms underline this association are still unclear, extended periods of cyanosis and pulmonary over circulation maybe factors that inversely impact brain growth and subsequent neurodevelopment if the surgery's not done early. The timing of surgery may have an impact on neurodevelopment in other forms of congenital heart disease, too, therefore. So all of this is discussed in an editorial entitled Correction of TGA, "Sooner Rather than Later?", and this is by Doctors Rollins and Newburger, from Boston's Children's Hospital. Dr Gregory Hundley:       Fantastic Carolyn, well I'm going to discuss a paper from the World of Basic Science from the Ohio State University, Wexner Medical Center from Doctor Douglas Lewandowski. And it involves the preservation of Acyl-CoA and how that attenuates pathological and metabolic cardiac remodeling through selective lipid trafficking. So Carolyn, it has been shown that metabolic remodeling in heart failure contributes to dysfunctional lipid trafficking, and lipotoxicity. Acyl-Coenzyme A Synthase One, or ACLACSL1 facilitates long chain fatty acid uptake an activation with coenzyme A, mediating the fate of the long chain fatty acids. The authors tested wither cardiac Acyl coenzymes A synthase One over-expression aided long chain fatty acid oxidation and reduced lipotoxicity under the pathologic stress of transverse aortic constriction or TAC. Dr Carolyn Lam:                Interesting, I like that concept of metabolic remodeling. So what did they find? Dr Gregory Hundley:       So Carolyn, the studies were performed in both mice and in human subjects, and in mice at 14 weeks, TAC induced cardiac hypertrophy and disfunction was mitigated in MHCACSL1 hearts compared to nontransgenic hearts. This was manifest by retain greater rejection fraction, 65.8 percent versus the nontransgenic hearts of 45.9 percent. An improvement in diastolic E over E prime. Also, functional improvements were mediated by ACSL1 changes to cardiac long chain fatty acid trafficking. In humans, long chain Acyl-CoA was reduced in human failing myocardium and restored to control levels by mechanical unloading.                                                 So, Carolyn, this is the first demonstration on reduced Acyl-Co-A in failing hearts of humans and mice, and suggest possible mechanisms for maintaining mitochondrial oxidative energy metabolism by restoring long chain Acyl-CoA through ASCL1 activation and mechanical unloading. Dr Carolyn Lam:                Awesome Greg! Thanks so much for sharing that paper. Let's go on to our feature discussion. Dr Gregory Hundley:       You bet. Dr Carolyn Lam:                Our feature discussion today is about transcatheter aortic-valve replacement. Could this be the new gold standard for the treatment of aortic stenosis? And yes, I am borrowing from the title of the editorial that accompanies our feature paper. With the editorialists right here with us, Dr Bernard Prendergast, from Saint Thomas' Hospital in London, and we are talking about the wonderful paper for the notion trial and that's a Nordic aortic valve intervention randomized clinical trial, and we're here with the first and corresponding author of that paper Dr Hans Gustav Thyregod from Copenhagen University Hospital, and we also have our associate editor Dr Dharam Kumbhani from UT Southwestern. So welcome gentlemen! And for a start could I ask Hans to please describe the results of the notion trial. Dr Hans Thyregod:           The notion trial as you said is the Nordic aortic valve intervention trial. Designed to compare transcatheter therapy and surgical therapy and patients with severe aortic valve stenosis, patients have to be thirteen years old or older and we didn't really specify any risk profile, as in previous trials. So all patients eligible for both procedures would be enrolled in the trial. And the main result of the trial was that we couldn't find a difference when looking at the composite outcome, which was all-cause mortality, stroke American infraction.                                                 The primary outcome was after one year, in this paper it's up to five years and we could not see any difference. So the range was, in my estimate was 38 percent for transcatheter therapy versus 36.3 percent for surgery. And when looking at the different components of this composite outcome, all-cause mortality, stroke American infraction. We couldn't find any surgically significant difference for any of those outcomes either. Dr Carolyn Lam:                Wow, Bernard, could I ask you to place these results into context for us, I mean the notion trial is after all the first to compare TAVR and SAVR in patients with severe isolated valve stenosis at lower surgical risk, and really has the longest follow-up doesn't it? So please tell us, what are your thoughts? Dr Bernard Prendergast:               So this is yet another notch the remarkable success story of TAVI or TAVR, as you call it in the U.S. We pass our congratulations from the community to Dr Thyregod and the team in Copenhagen for such a ground-breaking study. The wider context is he say is the TAVR have demonstrated remarkable efficacy and safety, initially in operable and high-risk patients, but, more recently randomized control trials in intermediates and lower risk patients. And the important perspective of this study provides is the longer term follow up, because for a number of years we've perhaps considered TAVI or TAVR as a, let’s say a shorter-term treatment for patients in their eighty's and older, who perhaps have a shorter life expectancy. But what the five-year data demonstrates to us is that TAVI or TAVR is as good as surgery, at five years of follow up. With very reassuring outcomes, they maintain durability of the transcatheter heart valve, that's highlighted in the companion paper, which, is published very recently in JACC.                                                                 So really takes TAVI into a new territory, which is patients who have at least five years or longer to live and allows us to extend the indication for the procedure into younger patients. Alongside lower risk patients, who have supported by the recent landmark studies published in the New England Journal from Partner Three, and the Core Valve Low Risk trial. So, the information is very reassuring and it's another very positive notch in the journey of TAVI across the spectrum of surgical risk. Dr Carolyn Lam:                Thank you! Beautifully put and Dharam could I just ask you I mean what more do we need? Do you think this is guideline defining stuff now? Or do you have questions? Dr Dharam Kumbhani:   I really want to congratulate the investigators of the NOTION trial, as far as providing us with this longer term follow up in a lower risk population, and so, you know the field is moving incredibly, incredibly quickly and you know as we just mentioned TAVR has now gone from being something that's done in patients that are too high risk to level convention surgery, to now perhaps becoming either one of the main stream options, or the main stream option. And you know time will tell, so I think what this study really helps us is, provide us with a five-year time horizon on follow up, but, to be fair, you know this trial is very helpful in certain ways because it was designed a few years ago. You know it was done with the generation of a valve that is not used much right now for the most part, and you know so it's some of the things like pacemaker et cetera, may not translate to current practice.                                                 Even though the clinical outcomes were similar, it's probably some issues with power as well, but, again not in a clinical way, but, just to kind of say that this trial definitely helps us in moving the field forward and it kind of adds to the growing body of literature that supports that. Going forward I guess one question I would have for this group is, you know as we think about TAVR and surgical aortic replacement, it would seem that we would need even longer term data, based off of detonators to be able to confidently tell patients, there are fairly similar therapies.                                                 And then the other question is, this construct of surgical risk is that we applied telegraphically based on how the evolution of TAVR has occurred, but one wonder, you know with NOTION and other trials we should be thinking about this perhaps from an age perspective as a sort of NOTION trial—those would be my two comments. Dr Bernard Prendergast:               I think that's a very valuable comment, and of course there are other ongoing trials, which, will help to address many of these questions. One important deficit of notion is that it didn't enroll, for example, patients with bicuspid aortic valves. And we know that bicuspid aortic stenosis is far more common in younger patients. So, Hans a few comments regarding the protocol for notion two maybe helpful for our listeners. Dr Hans Thyregod:           Well this was mentioned, the follow up of five years is obviously not a very long time in younger patients with a lower risk profile. We are planning to follow these patients for at least 10 years. And the other comment about the risk profile of the risk certification of patients is also very interesting because the SDS and your scores have been developed for surgical patients and not for transcatheter patients. So we need a whole new transcatheter risk scoring system to help our team determining what treatment would be the best suited for each patient.                                                 And as Dr Prendergast mentioned we are in Copenhagen, and Scandinavia conducting a NOTION II trial, which, will enroll patients younger than the previous low risk trials and also the notion trial. Which, at a mean age, at least for the patient of around 80 years and in notion two patients must be younger than 75 years old. And we are also including patients with bicuspid valve stenosis, and also patients which were not included in the NOTION I trial. Patients with a coronary artery disease, so these patients are obviously also a different patient category and will maybe require a different approach regarding the timing of the revascularization and so forth so there is more research to be done in those areas. Dr Carolyn Lam:                Well exciting. Thank you for sharing that Hans. Dharam could I ask you to just wrap us up with the take home message, it's for our audience right now. Dr Dharam Kumbhani:   For me one of the most interesting findings was that in five years, the clinical performance between TAVR and SAVR were similar, but, more importantly the valve performance, the hemodynamic performance was the same, and perhaps slightly better with the self-expanding design. They are so proud of the self-expanding design that was studied in the study. So that is helpful because as we discussed earlier, I think a lot of the controversy discussions centers around the long-term durability of TAVR compared with surgically aortic valve replacement, so that is a step in the right direction. The same investigators have published that hemodynamic performance elsewhere as well, sot that's I think the number one take home message that, that's very, very reassuring. The second thing is you know this study shows us it adds to the growing body of literature, in lower risk patients so all of this was not strictly a lower risk trial based on contemporary definition.                                                 It was definitely a lower risk population and so, this is the largest pool of patients where they aortic stenosis about 50 percent will have low risk aortic stenosis, low surgical risk aortic stenosis and so this is very helpful in that space and then third you know that this is very exciting that NOTION investigators indeed are the low risk trial investigators, will be extending their follow up with 10 years. So I think in this next decade, most people expect as Dr Prendergast also mentioned, we'll see a gradual change perhaps in how patients with aortic stenosis manage. But, I will add a word of caution, I think in the current era, the way things stand right now, it's probably best in favor to appeal to what the guideline indicates. And for the low risk patients, surgical aorta valve replacement is still the center of choice. Dr Carolyn Lam:                Thank you so much Dharam and thank you Hans for the beautiful paper, and Bernard for that excellent editorial!                                                 Thank you audience for joining us today, you've been listening to Circulation on the Run. Don't forget to tune in again next week.                                                 This program is copyright American Heart Association 2019.  

Why would a young child not be able to break down fatty acids during a long period of fasting?

In this Episode first Author Brianne Kent speaks to us about her recent paper 'The orexigenic hormone acyl-ghrelin increases adult hippocampal neurogenesis and enhances pattern separation' published in Psychoneuroendocrinology.

Última parte do especial de misturas de estilos, destacando Ethnic, Oriental, Avant-gatde e Extreme Pop no Heavy Metal. Bandas da playlist: Acyl, Arkan, Orphaned Land, Senmuth, Melechesh, Solefald, Hesus Attor, Dubioza kolektiv, Jinjer, Russkaja, Kontrust, Dirty Shirt, Ninjaspy, Kells, 6h33, Trepalium, Babymetal, Infected Rain, Exilia, Dead by April, Amaranthe, Straight Line Stitch, Butcher Babies, In This Moment, e ainda o último destaque ao grupo Tellus Terror.

Última parte do especial de misturas de estilos, destacando Ethnic, Oriental, Avant-gatde e Extreme Pop no Heavy Metal. Bandas da playlist: Acyl, Arkan, Orphaned Land, Senmuth, Melechesh, Solefald, Hesus Attor, Dubioza kolektiv, Jinjer, Russkaja, Kontrust, Dirty Shirt, Ninjaspy, Kells, 6h33, Trepalium, Babymetal, Infected Rain, Exilia, Dead by April, Amaranthe, Straight Line Stitch, Butcher Babies, In This Moment, e ainda o último destaque ao grupo Tellus Terror.

Última parte do especial de misturas de estilos, destacando Ethnic, Oriental, Avant-gatde e Extreme Pop no Heavy Metal. Bandas da playlist: Acyl, Arkan, Orphaned Land, Senmuth, Melechesh, Solefald, Hesus Attor, Dubioza kolektiv, Jinjer, Russkaja, Kontrust, Dirty Shirt, Ninjaspy, Kells, 6h33, Trepalium, Babymetal, Infected Rain, Exilia, Dead by April, Amaranthe, Straight Line Stitch, Butcher Babies, In This Moment, e ainda o último destaque ao grupo Tellus Terror.

When a nucleophilic atom bearing a good leaving group attacks a carbonyl group, an adjacent R group can migrate to the new atom, inserting it into the R-acyl bond. This mechanism can insert O, NH, or CH2 groups into the acyl bond with informative stereospecificity in the case of the Beckmann rearrangement of oximes. Although the migrating groups are formally anionic, relative migratory aptitudes show that they give up electron density during rearrangement. Acid dissociation of protons [gr]α to a carbonyl group to form enolates, and the ease of forming enols, gives [gr]α-carbons nucleophilic reactivity under both basic and acidic conditions. This explains H/D exchange and racemization as well as halogenation and alkylation of [gr]α-carbons. Complete course materials are available at the Open Yale Courses website: http://oyc.yale.edu This course was recorded in Spring 2011.

http://webs.anokaramsey.edu/aspaas/2061/video/21.8%20Biological%20thioesters%20and%20acyl%20phosphates.m4v Sat, 09 Apr 2011 13:24:02 -0500 Higher Educ

http://webs.anokaramsey.edu/aspaas/2061/video/21.2%20Nucleophilic%20acyl%20substitution.m4v Sat, 09 Apr 2011 13:24:08 -0500 Higher Education

One of the important transformations of alcohols to esters is the reaction with acetic anhydride catalysed by 4-(dimethylamino)pyridine (DMAP) in the presence of an auxiliary base like triethyl amine. Although this is a widely used reaction, several questions left unaddressed until now: the reaction mechanism of the latter transformation was not completely conceived. Since Steglich and Litvenencko found DMAP in 1969 independently as nucleophilic catalyst, there was hardly any effort to search for new nucleophilic catalysts of higher catalytic efficiency than DMAP or 4-(pyrrolidinyl)pyridine (PPY). All chiral nucleophilic catalysts are based on these structural motifs and due to their lack of catalytic efficiency, there are hitherto no examples for kinetic resolution experiments of tertiary alcohols described. In this dissertation, the following goals were achieved: With computational methods, the reaction pathway of tert-butanol with acetic anhydride in the presence of DMAP was explored. Based on these results a fast computational tool was developed to screen for more efficient nucleophilic catalysts. The best candidates were synthesised, the catalytic efficiency quantified and the best catalysts applied in the synthesis of esters. The reaction mechanism of the acetylation of tert-alcohols was explored by calculating the nucleophilic and base catalysed reaction pathway of tert-butanol with acetic anhydride in the presence of DMAP at B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level of theory. In the course of this study, a nucleophilic and base catalysed reaction pathway with DMAP as catalyst was found. The energetically lowest transition state of the base catalysed reaction pathway is 37.9 kJ mol-1 higher in energy then the energetically lowest transition state in the rate-determining step of the nucleophilic reaction path. The combination of kinetic measurements with the calculation of the nucleophilic reaction path reveals that no triethyl amine is involved in the rate-determining step of nucleophilic reaction pathway. This shows clearly that nucleophilic catalysis is the preferred and that the acetate anion is deprotonating the alcohol in the rate-determining step. Furthermore, the results of the recalculation of the nucleophilic reaction path with a different catalyst show that a higher stabilisation of the transient acylpyridinium cation has a pivotal influence on the overall reaction rate of the ester formation. Therefore, relative acetylation enthalpies (ΔH298) were calculated at B3LYP/6-311+G(d,p)//B3LYP/6-31G(d) level of theory by using an isodesmic reaction approach. In this way a large number of new nucleophilic catalysts were screened and numerous promising candidates were synthesised which have a larger negative ΔH298 value then DMAP (-82.1 kJ mol 1). The catalytic effiency of the new nucleophilic catalysts was quantified by a test reaction using 1 equiv. of 1-ethynylcyclohexanol, 2 equiv. of acetic or isobutyric anhydride and 3 equiv. triethyl amine. The conversion of 1-ethynylcyclohexyl acetate or -isobutyrate was monitored by 1H NMR spectroscopy. Pyrido[3,4-b]pyrazine- and pyrido[3,4 b]quinoxaline-derivatives show the best catalytic effiency. Especially (rac) 5,10-diethyl-5,5a,6,7,8,9a,10-octahydropyrido[3,4 b]-quinoxaline (DOPQ) shows equal to better catalytic efficiency then 6,6-tricyloaminopyridine (TCAP), which was hitherto the best nucleophilic catalyst. DOPQ can be synthesised very efficiently in a four step protocol starting from commercially available 3,4-diaminopyridine and cyclohexane-1,2-dione with an overall yield of 45 % while TCAP is only available in a five step synthesis with an overall yield of 8-13 %. The synthesis of DOPQ starts with the Schiff-base formation of 3,4-diaminopyridine and cyclohexane-1,2-dione. Reduction with LiAlH4 yields the cis-configured octahydro[3,4-b]quinoxaline, which can be alkylated without the use of any protecting group in the presence of acetic anhydride in pyridine and subsequent reduction with LiAlH4/AlCl3 to yield DOPQ. The structure of the latter compound was confirmed by X ray single crystal structure. The new catalysts were applied to an enhanced Gooßen esterification to transform sterically hindered acids to their tert-butyl esters. The reaction mechanism was explored by monitoring the substrate, intermediate and product conversions with 1H NMR spectroscopy. With this enhanced reaction protocol, it was possible to transform 1-phenylcyclohexane carboxylic acid into the tert-butyl ester under high concentration conditions at room temperature in the presence of 5 mol% DOPQ within 270 min while with the standard DCC/DMAP protocol only the anhydride of the carboxylic acid is formed. With this very mild method, it was possible to convert a variety of substrates into their tert-butyl- and benzyl esters, which are not accessible with any other method starting from the free carboxylic acid. In the case of chiral substrates no lose of stereochemical information was detected. Combination of high concentration conditions and new catalysts provide attractive reaction times of a few minutes instead of several hours with the Gooßen protocol.

Thu, 29 Mar 2007 12:00:00 +0100 https://edoc.ub.uni-muenchen.de/6773/ https://edoc.ub.uni-muenchen.de/6773/1/Pongratz_Julia.pdf Pongratz, Ju

Mit dieser Doktorarbeit wurde das Konzept von gemischt bimetallischen Reagenzien erfolgreich eingeführt. Hierbei wurden magnesierte Borester selektiv dargestellt und mit Elektrophilen umgesetzt. Dabei wurde der erste Halogen-Metall-Austausch in Gegenwart einer Borgruppe verwirklicht. Desweiteren wurden Reaktionen zur Funktionaliserung von Bororganylen etabliert, bei denen dem Produkt die wertvolle Kohlenstoff-Bor-Bindung erhalten bleibt und so weiteren Elaborierungen zur Verfügung steht. Ausserdem wurden magnesierte Acyl-substituierte Indolderivate durch eine Halogen-Magnesium-Austauschreaktion dargestellt. Im letzten Projekt wurden erfolgreich direkte mono- und multipel-magnesierte carbocyclische Arene mit TMPMgClLiCl dargestellt und mit Elektrophilen umgesetzt.

Oxidation of low-density lipoprotein (LDL) generates proinflammatory and prothrombotic mediators that may play a crucial role in cardiovascular and inflammatory diseases. In order to study platelet-activating components of oxidized LDL 1-stearoyl-2-arachidonoyl-sn-glycero-3- phosphocholine, a representative of the major phospholipid species in LDL, the 1-acyl-phosphatidylcholines (PC), was oxidized by CuCl2 and H2O2. After separation by high-performance liquid chromatography, three compounds were detected which induced platelet shape change at low micromolar concentrations. Platelet activation by these compounds was distinct from the pathways stimulated by platelet-activating factor, lysophosphatidic acid, lyso-PC and thromboxane A(2), as evidenced by the use of specific receptor antagonists. Further analyses of the oxidized phospholipids by electrospray ionization mass spectrometry structurally identified them as 1-stearoyl-2-azelaoyl-sn-glycero-3-phosphocholine (m/z 694; SAzPC), 1-stearoyl-2-glutaroyl-snglycero-3- phosphocholine (m/z 638; SGPC), and 1-stearoyl-2-( 5-oxovaleroyl)-sn-glycero-3-phosphocholine (m/z 622; SOVPC). These observations demonstrate that novel 1-acyl-PC which had previously been found to stimulate interaction of monocytes with endothelial cells also induce platelet activation, a central step in acute thrombogenic and atherogenic processes. Copyright (C) 2005 S. Karger AG, Basel.

Eine über einen Reaktivitätsbereich von 24 Zehnerpotenzen sich erstreckende Serie von Referenzelektrophilen (Benzhydrylkationen und Chinonmethiden) wurde genutzt, um die nucleophile Reaktivität unterschiedlicher Substanzklassen zu vergleichen. Zu diesem Zweck wurde die Kinetik der Reaktionen von Benzhydrylkationen mit Diazoverbindungen photometrisch in Dichlormethan untersucht. In analoger Weise wurden die Reaktionen von Benzhydrylkationen mit hochstabilisierten Carbanionen in Wasser durchgeführt. Es handelte sich dabei um Carbanionen, die alle durch zwei Acyl-, Ester-, Cyano- oder durch eine Nitrogruppe stabilisiert waren. Die Nucleophilieparameter N und die Steigungsparameter s dieser Nucleophile wurden aus der Linearen-Freien-Energie Beziehung log k(20 °C) = s(E + N) abgeleitet und mit der Nucleophilie anderer n- und p-Systeme verglichen. Es stellte sich heraus, dass sich die nucleophilen Reaktivitäten von Diazoverbindungen über mehr als zehn logarithmische Einheiten erstrecken. Die wenig reaktiven Verbindungen besitzen eine ähnliche Nucleophilie wie Styrol während die nucleophilsten Diazoverbindungen Enaminen entsprechen. Der geschwindigkeitsbestimmende Schritt ist der elektrophile Angriff am Diazo-Kohlenstoff wobei Diazonium-Ionen entstehen die rasch Stickstoff abspalten. Während die Acyl- und Ester-substituierten Carbanionen in Wasser ungefähr drei Größenordnungen weniger reaktiv sind als in DMSO, besitzt das Anion von Malonsäuredinitril in beiden Lösungsmitteln ähnliche Reaktivität. Die Nitro-substituierten Carbanionen zeigen ein grundlegend anderes Verhalten. Es zeigte sich, dass die rein aliphatischen Nitro-substituierten Carbanionen in DMSO 8 bis 10 Einheiten reaktiver sind als in Wasser, wohingegen sich die Arylsubstituierten Verbindungen in den beiden Lösungsmitteln nur um 3 bis 6 Einheiten unterscheiden. Bei den in dieser Arbeit untersuchten Carbanionen in Wasser wurde nur eine sehr mäßige Korrelation der Nucleophilieparameter N (Reaktivität) mit den pKa-Werten (Basizität) der jeweiligen korrespondierenden CH-Säuren gefunden.

N-Acylhomoserinlactones (AHL) are signalling molecules in gram-negative bacteria, which regulate, in a cell density dependent way, important interactive functions. This phenomenon is known as quorum-sensing. This work characterised the microbial ecology of the autoinducer (AHL) producing bacteria Serratia liquefaciens MG1 and Pseudomonas putida IsoF in the rhizosphere of tomato plants. Gfp- and rfp-tagged strains of the AHL producing wiltypes S. liquefaciens MG1 and P. putida IsoF were compared with its AHL-negative mutants, which were unable to produce AHL. Two kinds of plants cultivating systems were used: a defined axenic system and a complex soil system. The characterisation of the root colonisation behaviour was performed using confocal laserscanning microscopy (CLSM) and cell counting of bacteria. Fluorescence in situ hybridisation (FISH) and terminal restrictions fragment length polymorphism (t-RFLP)-techniques were used to examinate shifts of the bacterial population in the rhizosphere on tomato plants. The effective in situ production and spreading of AHL on tomato roots was demonstrated with P. putida IsoF using an AHL-sensor strain P. putida F117 pKR-C12. AHL was produced in effective concentrations in the rhizosphere of tomato plants and influenced the bacterial rhizosphere population. However, the AHL-production had no influence on the colonization behaviour of the AHL-producing strains S. liquefaciens MG1 and P. putida IsoF.

Eliminierung von HCl aus dem sechsfach koordinierten Komplex Cl2(Ph3P)2 liefert den α-Acylesterenolat-Komplex (Cl)Ph3P)2 (1) mit der Koordinationszahl 5. Die Röntgenstrukturanalyse zeigt für 1 eine verzerrte tetragonal pyramidale Struktur mit der Acylgruppe an der Spitze. An den 16-Elektronen-Komplex 1 lassen sich (reversibel) CO und CH3CN addieren.

Thu, 1 Jan 1987 12:00:00 +0100 http://epub.ub.uni-muenchen.de/4088/ http://epub.ub.uni-muenchen.de/4088/1/4088.pdf Wanner, Klaus Th.; Kärtner, Annerose Wanner, Klaus Th. und Kärtner, Annerose (1987): Isomerization of N-acyl-1,2,5,6-tetrahydropyridines to N-acyl-enamines by palladium on carbon. In: Heterocycles, Vol. 26, Nr. 4: pp. 917-919.

Fri, 1 Jan 1982 12:00:00 +0100 http://epub.ub.uni-muenchen.de/3485/ http://epub.ub.uni-muenchen.de/3485/1/033.pdf Soll, Jürgen; Roughan, Grattan Soll, Jürgen und Roughan, Grattan (1982): Acyl—acyl carrier protein and pool sizes during steady-state fatty acid synthesis by isolated spinach chloroplasts. In: FEBS Letters, Vol. 146, Nr. 1: pp. 189-192.