Carolyn Lam, MBBS, PhD

Circulation May 18, 2021 Issue

Circulation May 18, 2021 Issue

This week, please join author Uwe Tietge and Associate Editor Anand Rohatgi as they discuss the article "High-Density Lipoprotein Anti-Inflammatory Capacity and Incident Cardiovascular Events" (https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.120.050808) 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, we've got a very interesting feature this week. It involves another paper in the line of the story of HDL, and looking at HDL and future cardiovascular events. But before we get to that, how about we grab a cup of coffee and jump in and review the other articles and the issue? And Carolyn, this week, maybe I'll go first. Dr. Carolyn Lam: Go, I've got my coffee. Dr. Greg Hundley: Very good. So Carolyn, this paper comes to us from Dr. Huso Hakala, from the University of Turku at Turku University Hospital, and the study pertains to cognition and cardiovascular disease. So Carolyn, as you know, cardiovascular risk factors such as high blood pressure, adverse serum lipids, and elevated body mass index, and midlife may harm cognitive performance. So importantly, perhaps the presence of cardiovascular risk factors since childhood, Carolyn, may impact cognition later in life. So these authors studied the associations of the cardiovascular risk factors from childhood to midlife, their accumulation and midlife cognitive performance. They gathered their data beginning in 1980 from a population-based cohort of 3,596 children who are aged three to 18 years that were repeatedly followed up for 31 years, and they assess blood pressure, serum lipids, body mass index, all in the follow-ups. Dr. Carolyn Lam: Wow. So accumulating risk, I suppose, Greg. So what did they find? Dr. Greg Hundley: Great. Carolyn, glad you asked. So consistently high systolic blood pressure or serum total cholesterol associated with worse midlife episodic memory and associated learning, compared to situations when blood pressure or cholesterol values were low. Obesity since childhood associated with worse visual processing and sustained attention compared to individuals or children that had normal weight. And an inverse trend association was observed for the cardiovascular risk factor accumulation with episodic memory and associated learning with visual processing and sustained attention and with reaction and movement time. So the take home Carolyn, is that, maybe we should be launching preventative strategies against some of these cardiovascular risk factors beginning in childhood, because perhaps they could benefit primordial promotion of cognitive health for those later in adulthood, maybe like you and me. Dr. Carolyn Lam: Oh, wow. Thinking back on my blood pressure, cholesterol and weight, I suppose, since childhood, yikes. Well, the next paper Greg is an important analysis from DAPA-HF. Now as a reminder in the DAPA-HF trial, the sodium glucose co-transporter two inhibitor dapagliflozin was shown to reduce the risk of cardiovascular death and a first episode of worsening heart failure, in patients with heart failure with reduced ejection fraction or HFpEF. In the current paper from Drs. Jhund and colleagues from University of Glasgow, they described the efficacy of dapagliflozin on the predefined secondary end point of total heart failure hospitalizations. That's the first and recurrent heart failure hospitalization and cardiovascular death. And this is so important because we know that patients with HFrEF are known to experience multiple episodes of heart failure during the course of the disease. Dr. Greg Hundley: So Carolyn, what did they find? Dr. Carolyn Lam: Well, they did this analysis by two methods in the first, which was the Lin, Wei, Ying and Yang or LWYY model the rate ratio for the effect dapagliflozin on recurrent heart failure, hospitalizations or cardiovascular death was 0.75. Dr. Carolyn Lam: And the second method, a joint frailty model, the rate ratio for total heart failure hospitalizations was 0.71 while for cardiovascular death, the hazard ratio was 0.81. The factors associated with more hospitalizations were, being a men, having a higher heart rate, NT-proBNP, New York Heart Association class type 2 diabetes, and a longer duration of heart failure with less hospitalization in those with higher systolic blood pressure and higher ejection fraction. So in summary, dapagliflozin in reduced the risk of total heart failure, hospitalizations and cardiovascular death. In fact, if you compare it to the time to first analysis, you can see that, that actually underestimated the benefit of dapagliflozin in HFpEF. Dr. Greg Hundley: Very nice Carolyn, well, my next paper comes to us from the world of basic science. And so Carolyn, neonatal mouse cardiomyocytes undergo a metabolic switch from glycolysis to oxidative phosphorylation, which results in a significant increase in reactive oxygen species production that induces DNA damage. These cellular changes contribute to cardiomyocytes cell cycle exit and loss of the capacity for cardiac regeneration. Now the mechanisms that regulate this metabolic switch and the increase in reactive oxygen species production have been relatively unexplored. Dr. Carolyn Lam: Okay, Greg. So what did this current paper find? Dr. Greg Hundley: Right, Carolyn, so Dr. Ahmed Mahmoud from University of Wisconsin-Madison, they found that malonate, a competitive inhibitor of succinate dehydrogenase, promotes adult cardiomyocyte proliferation, revascularization of the infarct zone and myocardial regeneration following infarction. They also found that SDH inhibition by malonate is consistent with a metabolic shift from oxidative phosphorylation to glucose metabolism in the adult heart. So Carolyn, the clinical implications include the observation that transient inhibition of SDH may represent an important metabolic target to promote adult heart regeneration, following myocardial infarction. Dr. Carolyn Lam: Cool. Thanks Greg. Well, I've got another basic science paper. Let me try to tell you about la ribonucleoprotein domain family member seven. And I'm going to call that LARP7. Again, it's la ribonucleoprotein domain family members seven. Now LARP7 is a master regulator that governs the DNA damage response. The authors today, Dr. Zhang, from Xin Hua Hospital and Shanghai Jiao Tong University and colleagues aim to study its role in heart failure, pathogenesis by assessing LARP7 expression in human heart failure and in non-human primate and mouse heart failure models. Dr. Greg Hundley: Great, Carolyn. So what did they find? Dr. Carolyn Lam: LARP7 was essential for mitochondrial biogenesis energy production and cardiac function by modulating silent mating type information regulation to homolog-1, which is cert one, cert one homeostasis and activity. Now, reduction in LARP7 and diseased hearts due to activation of ataxia-telangiectasia mutated protein pathway contributed to the heart failure pathogenesis and conversely restoring LARP7 in the injured heart conferred myocardial protection. So in some, these results identified that this LARP pathway is a target or rather is a potential target for therapeutic intervention in heart failure. Dr. Greg Hundley: Great, Carolyn. One of the things I love about our journal is really the translational basic science that really could have future implications for how we manage patients with cardiovascular disease. So I, to follow, have another basic science article, and it comes to us from Dr. Florian Weinberger from the University Medical Center in Hamburg-Eppendorf. So Carolyn, human engineered heart tissue transplantation represents a potential regenerative strategy for our heart failure patients and has been successful in preclinical models. Clinical application requires upscaling, adaptation to good manufacturing practices and determination of the effective dose. So these authors performed studies in which cardiomyocytes were differentiated from three different human induced pluripotent STEM cell lines, including one reprogrammed under these GMP conditions. Protocols for human induced pluripotent STEM cell expansion, cardiomyocyte differentiation and engineered heart tissue generation were adapted to substances available in good manufacturing process quality. Engineered heart tissue geometry was modified and repair efficacy was evaluated at three doses in a cryo-injury Guinea pig model, human scale patches were epicardialy transplanted onto healthy hearts in pigs to assess the technical feasibility of this entire process. Dr. Carolyn Lam: Wow. And what did they find? Dr. Greg Hundley: Right, Carolyn? I mean, this is just so exciting, the practicality of how you implement some of these new strategies that we work on in the lab. So Carolyn, they found that human engineered heart tissue patch transplantation resulted in a partial re-muscularization of the injured heart and improved left ventricular function in a dose dependent manner in a Guinea pig injury model and human scale patches were successfully transplanted in pigs in a proof of principle study. So an exciting new front for engineered cardiac tissue transplantation. I mean, this is a really exciting article. Dr. Carolyn Lam: Wow, well, indeed. Thanks, Greg. Well, other than those wonderful papers in today's issue, we have an exchange of letters between Drs. Morgan and Lopes regarding initial invasive versus conservative management of stable ischemic heart disease patients with a history of heart failure of left ventricular dysfunction and that's insights from the ischemia trial. Tracy Hampton does her wonderful review from the literature and it covers new research published in nature medicine, which indicates the impact of a Mediterranean diet on cardio-metabolic disease risks, which may be affected by an individual's gut microbes and goes all the way to network correcting therapeutic candidate for heart valve disease, which was published in science and even a newly discovered genetic arrhythmia syndrome, which was described in science translational medicine. That's a perspective piece by Dr. Kuwabara on the Japanese national plan for promotion of measures against cerebral vascular and cardiovascular disease. Dr. Greg Hundley: Great, Carolyn. Well, you've heard of mission accomplished. Well, Dr. Brooke has an On My Mind piece entitled mission unaccomplished, the optimal hyper, any hypertensive therapy. And then finally, Dr. Glembotski has a Research Letter entitled optimizing AAV9 for studies of cardiac chamber specific gene regulation. Well, Carolyn, what a great issue and integrating all the wonderful world of basic science in a translational fashion. Now, how about we get on and move toward our feature discussion? Dr. Carolyn Lam: Yep. HDL, here we come. Dr. Greg Hundley: Well, listeners, we are onto our feature discussion today and we're very excited to have with us today, professor Uwe Tietge from Stockholm, Sweden, and our own associate editor Anand Rohatgi from UT Southwestern. Welcome gentlemen. And Uwe, could you describe for us the hypothesis that you wanted to test and tell us a little bit about your study design? Dr. Uwe Tietge Okay. So thank you very much for inviting me and for having the opportunity to discuss this article with you today. So we've been for a long time interested in HDL function, and we have developed an HDL anti-inflammatory see, and we have tested it in some cross-sectional studies. And we have seen in this cross-sectional work, for example, in the acute mi or diabetes, are associated with significant reductions in HDL anti-inflammatory function. So we felt that the next important step would be to study this prospectively in the general population. So this is why we made use of the prevent cohort, which is a prospective general population study with white participants from Groningen, which is a city in the North of the Netherlands. Prevent stands for prevention of menial and stage disease, and prevent has a total number of participants of 8,592. Dr. Uwe Tietge So we first excluded all that had already experienced mi intrusion. And then we took all subjects, was the first cardiovascular disease events during follow up and matched controls for sex, age, smoking, and importantly also for HDL cholesterol levels. And we felt that such a design would allow us to truly identify changes in HDL function, independent of HDL cholesterol levels. So then finally we ended up with 340 match case control pairs. Dr. Greg Hundley: Uwe, sounds like a very interesting hypothesis. So what was your methodology and how did you perform your analysis? And then also describe for us, what did you find? Dr. Uwe Tietge The key method that we used was our essay determining the atrial anti-inflammatory capacity and the main outcome measured was incident cardiovascular disease. And in our case, that was deaths from cardiovascular disease, hospitalization from mi, PDCA, ischemic heart disease, or CABG. We did not have stroke in our study. So with respect to HDL function, we isolate HDL by means of PEG precipitation. And this is an established method that is widely used in larger cohort studies. We then take a primary industry that cells, humans, and we pre incubate them for 30 minutes with the individual engineer preparations. Then the agents removed and TNF alpha is added for another five hours. And after these five hours, we isolate RNA and determine BK1 and mRNA levels by quantitative real time PCR. Then we calculate the results relative to the [inaudible 00:16:09] or without the edit HDL. So when the empties data, we use statistical analysis to determine the perspective association in, based on HDL anti-inflammatory function and the outcome measure incident CVD. Dr. Uwe Tietge So to summarize the main findings of the study. So first of all, the anti inflammatory activity of HDL baselines intrusion in this study was significantly higher in controls than in cases. Next, the HDL anti-inflammatory activity was not correlated with any other CBD related biomarkers. Importantly also know it was HDL cholesterol at 8.1, but also not, for example, with triglycerides, or isolated CRP, and also not with [inaudible 00:16:58] capacity, which is another function metric of HDL. Dr. Uwe Tietge The further finding was that in conditional logistic regression analysis, we found that baseline HDL anti-inflammatory activity was significantly associated with future CV events, even in a fully adjusted model. Then finally, when we were adding this function of HDL to the premium, this form, or when we were replacing anti-inflammatory capacity in the score that improved risk prediction and interestingly adding cholesterol reflux and other HDL function, as said before, resulted in a further improvement. Dr. Uwe Tietge So the general conclusion was that of the HDL functional measures in the case of our actual study, this is the HDL anti-inflammatory activity has the potential to provide clinic information independent of conventional use biomark. Dr. Greg Hundley: Very nice who made. So we always think of HDL is the good cholesterol. And sounds like you're describing a whole nother process by which HDL could be beneficial. Well, Anand turning to you now. I know you see many papers come across your desk. What drew your attention to this particular manuscript and how does this new HDL anti-inflammatory capacity or activity impact the remaining science that we have that focuses on other beneficial effects of HDL? Dr. Anand Rohatgi: Thank you, Greg. And I would like to first start by thanking Dr. Tika to submitting his article to circulation and thinking about us for his studies. I will say when this came across my desk, I became extremely excited as HDL function is an area that is near and dear to my heart as well. And Dr. Tika is an international expert in this area. So we are quite excited. The reason why this really picked our attention at circulation is that this was really the first and large demonstration that this novel marker on anti-inflammatory capacity was linked to the incidents of cardiovascular events, so that it wasn't just the range and people who already had disease, but at baseline, in people who are otherwise healthy, it could predict those who would go on to be at higher risk of atherosclerotic events. So in this case, what we saw was a truly unique and novel cardiovascular marker. Dr. Anand Rohatgi: It was a significant translational study working in effort on the part of Dr. Tika and his research team to be able to do this, and so many participants, this is not an easy undertaking. So to be able to do this and show the results that they were able to show is really remarkable, which is really why it elevated to our interest at circulation. A couple of things in terms of the implications in science are that when they recorded this study, they intriguinly we found that there were really no other stablished risk factors, cholesterol levels, or other markers that are associated with this novel anti-inflammatory capacity, it really wasn't associated with high sensitivity CRP, a global marker of inflammation. And it wasn't associated with the only other HDL function that had been shown to be linked to cardiovascular events, cholesterol influx. Dr. Anand Rohatgi: So really what we have here is a truly novel marker that stands on its own. And it's not confounded by the usual things of obesity or other cardiovascular risk factors, and is clearly imparting different information than a global marker, like CRP. I'll extend that these observations to one or two concepts, when it comes to inflammation, there are a couple of things to think about. One is the timing of the inflammatory cascade. A lot of markers are studied at the time where people are in an acute disease state and pro-inflammatory already, and so that can actually have an effect itself on the markers. In this case, by self-report, the participants did not have any acute illness. And so the relationship we see here between anti-inflammatory capacity and cardiovascular events is presumably in the context of a healthy, low inflammatory state. So I think that's important. The other thing that's important, I think for our audience to know is that the inflammation can have tissue specific effects. Dr. Anand Rohatgi: So when you think of global markers like CRP or interleukin 6, those are flagged systemic levels of inflammation in your body, and they are also predictive. But when it comes to atherosclerosis, we think about specific tissue types, the endothelium, macrophages, dipocytes. And in this case, what this marker represents is specific activity at the level of the endothelium, which is a key player in the atherosclerotic process. So it really gives us new and novel insights into that process. And it highlights the potential to find maybe therapeutic targets that can be more precise in targeting the atherosclerotic process and improving outcomes. So those were some of the main things that we saw that were exciting. Dr. Greg Hundley: Very nice. Uwe, as an international expert. What do you see as the next study that needs to be performed that will perhaps use this new market? Dr. Uwe Tietge I think what we need here first would be validation in another cohort and ideally a cohort that involves different ethnicities because our participants were predominantly white. So in terms of generalization, I think this is the next step that we would need. In terms of making this essay applicable to clinical settings in the daily routine, so to speak, we need to simplify it. And this is another issue that we are currently working on, trying to have an easier essay that gives us quicker readouts and ideally, maybe not using primary industry, but something that is better standardizable. And I mean, when you think about next steps, then also identification of a certain biomarker, comes to mind. So something that would reflect the dimension, the activity component of the age that reflects its functioning. And can be used in daily routine and is applicable. It lies to take all the types of essays. Dr. Greg Hundley: Very good. Anand, do you have anything to add to that? Dr. Anand Rohatgi: Well, I agree completely. I think when you always see a novel marker, you want replication and validation, and I think extending this to other nonwhite cohorts is important. The prevent cohort with 70% men, and also add average out there were probably higher than contemporary populations, at least in the United States. So it'd be nice to see an extension of these observations and cohorts that reflect that diversity. Interestingly, cholesterol wheat blocks the other HDL functions that's been associated with events is not linked through vascular events, it's mostly linked to coronary events. So it would be really interesting to find out how the anti-inflammatory capacity relates to events related to other vascular beds outside of the coronary tree. And then I guess a question that I had for professor Tika is, do you think there might be certain groups of people either by disease or demographic that this might be more powerful formative? Or do you think you would have the same kind of information across the board? Dr. Uwe Tietge Yeah, that's a relevant question of course. When we divided our population by participant level characteristics, we saw that there are sex differences. So the predictive capacity seems to be a bit better in females are significantly better than females, which is in male. And also in participants with lower BMI, with ahigher BMI. And the third parameter was in participants with was lower for this one was higher this month. So yes, I expect that some parameters can play a role here and it would be very wise to explore these connections. Dr. Greg Hundley: Very good. Well listeners, what an excellent discussion. And we want to thank Dr. Uwe Tika and his team from Stockholm, Sweden, and also our associate editor, Dr. Anand Rohatgi for bringing to us this new research regarding this marker of anti-inflammatory capacity involving HDL, that demonstrates an inverse association with cardiovascular events. Dr. Greg Hundley: On behalf of both Carolyn and myself. We want to wish you a great week and we will catch you next week on the run. Dr. Greg Hundley: This program is copyright of the American Heart Association, 2021. The opinions expressed by speakers in this podcast are their own and not necessarily those of the editors or of the American Heart Association, for more visit ahajournals.org.  

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