Nov 30, 2020
This week's episode features author Torbjørn Omland and Senior Guest Editor Vera Bittner as they discuss the artile "Growth Differentiation Factor-15 Provides Prognostic Information Superior to Established Cardiovascular and Inflammatory Biomarkers in Unselected Patients Hospitalized with COVID-19."
TRANSCRIPT BELOW:
Dr. Carolyn Lam:
Welcome to Circulation on the Run, your weekly podcast summary, and backstage pass to the journal and its editors. We are your co-hosts, I'm Dr. Carolyn Lam, associate editor from the National Heart Center and Duke National University of Singapore.
Dr. Greg Hundley:
I'm Dr. Greg Hundley, Director of the Pauley Heart Center at VCU Health in Richmond, Virginia. Well, Carolyn our feature this week gets into inflammatory biomarkers in patients that have been hospitalized with COVID-19, but before we get to that, how about we grab a cup of coffee and work through some of the papers in the issue. Would you like to go first?
Dr. Carolyn Lam:
Absolutely. With both the coffee and the papers. So great, for this first paper, have you thought about concentric versus eccentric cardiac hypertrophy? We traditionally associate them with pressure versus volume overload respectively in cardiovascular disease, both though conferring an increased risk of heart failure. These contrasting forms of hypertrophy are characterized by asymmetric growth of the cardiac myocytes in mainly width or length respectively. However, the molecular mechanisms determining myocyte preferential growth in width versus length remain poorly understood.
Dr. Carolyn Lam:
That is until today's paper, and it is from Dr. Kapiloff from Stanford University, and Dr. Rosenfeld from UCSD, School of Medicine and their colleagues, and what they did was used primary adult rat ventricular myocytes, as well as Adeno associated virus mediated gene delivery in mice, to define a regulatory pathway controlling pathological myocyte hypertrophy, and they found that asymmetric cardiac myocyte hypertrophy is modulated by serum response factor phosphorylation, constituting an epigenomic switch balancing the growth in width versus length of adult ventricular myocytes In vitro, and In vivo.
Dr. Carolyn Lam:
Serum response factor phosphorylation was bi-directionally regulated at signalosomes organized by the scaffold protein muscle, A kinase anchoring protein beta. This newly identified molecular switch controlled a transcriptional program responsible for modulating changes in cardiomyocyte morphology that occurs secondary to pathological stressors.
Dr. Greg Hundley:
Very nice, Carolyn. So switches controlling this transcriptional program. Tell us a little bit, and bring us back to the clinical relevance of this and starting with that concentric versus eccentric hypertrophy?
Dr. Carolyn Lam:
I thought you may ask. The identification of a molecular mechanism regulating that asymmetric cardiomyocyte growth, really provides a new target for the inhibition of pathological cardiac hypertrophy. Studies in mice using these Adeno associated virus based gene therapies to modulate that signalosome, really provided proof of concept for translational potential in the treatment of pathological cardiac remodeling and prevention of heart failure.
Dr. Greg Hundley:
Oh, wow. Very nice, Carolyn. Well, my first paper comes to us from Professor Dirk Westermann from Hamburg, and focuses on cardiogenic shock patients, and veno-arterial ECMO, the results from the international multicenter cohort study. So Carolyn this study evaluated data from 686 consecutive patients with cardiogenic shock treated with VA ECMO with or without left ventricular unloading using an Impella, and they conducted this at 16 tertiary care centers across four countries. They examined the association between left ventricular unloading and 30 day mortality.
Dr. Carolyn Lam:
Huh, so what did they find?
Dr. Greg Hundley:
Okay. Carolyn. Well, left ventricular unloading was used in 337 of the 686 patients enrolled, and after propensity matching 255 patients with left ventricular unloading were compared with the 255 patients without left ventricular unloading. In the match cohort, left ventricular unloading was associated with lower 30 day mortality without differences in the various subgroups. However, complications occurred more frequently in patients with left ventricular unloading, like severe bleeding, which happened in 38.4% versus only 17.9% in those without unloading. There was also access-related ischemia and renal replacement therapy.
Dr. Greg Hundley:
So Carolyn, the take-home message from this International multi-center cohort study, is that left ventricular unloading is associated with lower mortality, and cardiogenic shock patients treated with VA ECMO, despite higher complication rates. In the absence of randomized trial data these findings support the use of left ventricular unloading and cardiogenic shock patients treated with VA ECMO, and call for further validation, ideally in a randomized controlled trial.
Dr. Carolyn Lam:
Very nice. Well for my next paper, Greg, it's all about desmin. Now we know that mutations in the human desmin gene caused myopathies and cardiomyopathies. Well, today's authors, Dr. Hermann and Schroeder from University Hospital Erlangen in Germany and Dr. Lilienbaum from University of Paris and France and their colleagues, report an adolescent patient who underwent cardiac transplantation, due to restrictive cardiomyopathy caused by a heterozygous R406W desmin mutation. Sections of the explanted heart were analyzed with antibodies specific to 406W-desmin, and to intercalated disc proteins. Effects of this mutation on the molecular properties of desmin were then addressed by cell transfection and In vitro assembly experiments. They further generated these desmin mutation knock-in mice haboring the orthologous form of the human, R406W-desmin.
Dr. Greg Hundley:
So Carolyn, what did they find?
Dr. Carolyn Lam:
Well, they demonstrated a novel pathomechanism in which cardiotoxic R406W-desmin, could adapt dual functional status with the abilities to integrate into the indogenous intermediate filament network, and to cause formation a protein aggregates. This R406W-desmin modified the extra sarcomeric cytoskeleton, such that desmin filaments were not anchored to desmosomes anymore. Thereby destroying the structural, and functional integrity of intercalated discs.
Dr. Greg Hundley:
What are the clinical implications?
Dr. Carolyn Lam:
Well, since these cardiotoxic desmin mutations could affect the integrity of intercalated discs, thereby inducing conduction defects and malignant arrhythmias, they suggest early implantation of pacemaker, or cardioverter defibrillator devices, may be considered to prevent certain cardiac death in patients with these mutations. Furthermore, state-of-the-art basic molecular risk stratification of desmin mutations may encompass a multidisciplinary experimental approach as exemplified by the approach taken here, which comprises assessment of the tissue pathology in conjunction with genome analysis and desmin assembly studies as well as patient mimicking cell and animal models for the In vivo validation of these mutations.
Dr. Greg Hundley:
Well, fantastic, Carolyn. Well, my next paper comes to us from Dr. Ravi Shah from the Massachusetts General Hospital. This study evaluated 2,330 white and black young adults, average age of 32 years, in the Coronary Artery Risk Development in Young Adults, or the cardiac study, to identify metabolite profiles associated with an adverse cardiovascular disease phenom that included, myocardial structure and function, fitness, vascular calcification, and then also mechanisms, and other cardiovascular outcomes that would occur over the next two decades. Statistical learning methods, including elastic nets and principal component analysis, and Cox regression generated parsimonious metabolite based risk scores, validated in over 1800 individuals in the Framingham Heart Study.
Dr. Carolyn Lam:
Wow. What did they show, Greg? Wow, that's a lot of work.
Dr. Greg Hundley:
Yeah. So Carolyn, the authors found two multiparametric metabolite-based scores linked independently to vascular, and myocardial health. With metabolites included in each score specifying microbial metabolism, hepatic steatosis, oxidative stress, nitric oxide modulation, and finally collagen metabolism. Over nearly 25 year median follow-up, and cardia, this metabolite based vascular score, and the myocardial score, and the third and fourth decade of life were associated with clinical cardiovascular disease. Importantly, the authors replicated these findings in 1,898 individuals in the Framingham Heart Study followed over two decades, such that young adults with poor metabolite based health scores had higher hazard ratios of future cardiovascular disease related events.
Dr. Carolyn Lam:
Oh wow. Greg, what an elegant study with both development and validation cohort evaluating the metabolome.
Dr. Greg Hundley:
Yes. Carolyn. So metabolic signatures of myocardial, and vascular health in young adulthood specify known novel pathways of metabolic dysfunction, relevant to cardiovascular disease associated with outcomes in two independent cohorts. So these data suggests that efforts to include precision measures of metabolic health in risk stratification to interrupt cardiovascular disease at an early at stage, are warranted.
Dr. Carolyn Lam:
Wow. So interesting. Other very interesting articles in today's issue, there's an In Depth article by Dr. Angiolillo entitled, “The Antithrombotic Therapy for Atherosclerotic Cardiovascular Disease Risk Mitigation in Patients with Coronary Artery Disease and Diabetes.” There's also Research Letters, one by Dr. Sultan on, “The Longterm Outcomes of Primary Cardiac Lymphoma” and one by Dr. Wang on, “Loss of Phosphatase and Tensin Homolog Promotes Cardiomyocyte Proliferation and Cardiac Repair Following Myocardial Infarction.”
Dr. Greg Hundley:
Great, Carolyn. Well, I've got a couple other articles in this issue as well. One is by Professor Ganesan Karthikeyan who has an On My Mind piece entitled an “Alternative Hypothesis to explain Disease Progression in Rheumatic Heart Disease.” Dr. Stuart Chen has an ECG challenge entitled, “Alternating QRS Duration and a Normal T-waves. What is the mechanism?” Then finally, Carolyn, a series of Letters to the Editor, one by Dr. Peterzan and the other by Dr. Mehmood regarding the prior published article, entitled “Cardiac Energetics in Patients with Aortic Stenosis and Preserved Ejection Fraction.” Well, Carolyn, how about we get onto that feature article and learn more about inflammatory biomarkers in hospitalized patients with COVID-19?
Dr. Carolyn Lam:
Yes. Let's go. Greg.
Biomarkers are really playing an increasingly important role in cardiovascular disease, and even in the current COVID 19 pandemic, there's been a lot of news about how biomarkers such as traponin may be prognostic, and in fact, we're all wondering about maybe even newer biomarkers. In fact, today's feature discussion does bring to light one of the newest, and in fact, this is the first publication on the role of Growth Differentiation Factor 15 or GDF-15 in COVID-19. We're so pleased to be discussing this with the corresponding author, Dr. Torbjørn Omland from University of Oslo, in Norway, as well as our senior guest editor, Dr. Vera Bittner from University of Alabama at Birmingham. So welcome both. Tobjorn, could you tell us a little bit about GDF-15 and what made you look at it, and what did you find?
Dr. Torbjørn Omland:
Yeah, so GDF-15, that's a very interesting biomarker. It's considered a biomarker of biological aging cellular stress, and perhaps also the inflammation, and tests being studied within the cardiovascular field for some years now, and it has been shown to be a strong prognostic indicator across the cardiovascular spectrum, actually. So it is a new biomarker in one sense, but there are some data already in the cardiovascular field.
Dr. Carolyn Lam:
Not in COVID. So this is the first study to really look at its prognostic value in COVID 19. So congratulations Torbjorn, and if I may also to the first author, Dr. Peter Meer, a good friend as well, but please, could you tell us about your study and what you found?
Dr. Torbjørn Omland:
Yes. So when the COVID pandemic hit Norway in the spring, we thought that we should plan a prospective biomarker study. So we had to really fast track approval by the IRB and so forth, and we're able to actually cover most of the patients that were hospitalized in our hospital, Akershus University hospital, which is right outside of Oslo, and it's a pretty large hospital by Norwegian standards. It covers about 11% of the Norwegian population.
Dr. Torbjørn Omland:
So in that period, when we were including, we had 136 patients hospitalized with confirmed COVID 19, and we have biobank bank samples from 123 of these, and then there have been reports from retrospective studies, first from China, that seemed to suggest that markers like cardiac troponin, Anti-Troponin T, and Ferritin were associated with outcome, but those studies were prone to selection bias in that the measurements were performed in the most sick patients. So in this study we included all patients and then we thought we should examine a broad panel of biomarkers, and that included Interleukin 6, CRP, Procalcitonin, Ferritin, and the D-dimer Cardiac troponin, and N-terminal pro B, and GDF-15.
Dr. Carolyn Lam:
Wow. Thank you, Torbjorn. Even before you carry on with the results, can I just say having visited your hospital in pre-COVID days, I can only imagine what a work of love this was to do it prospectively. Any particular experiences to talk about, to get a fast-track even in the midst of to perform a well done prospective study, that must have taken a lot.
Dr. Torbjørn Omland:
Yes. But it's also interesting in that the whole sort of ablation on Norway was very much into this from the highest political level. Also, the decision that the older research on COVID should be prepared to retire, then the IRB had an eight hour and deadline for them to approve or not approve the study. So that's went surprisingly smoothly, I must say.
Dr. Carolyn Lam:
Wow, that's great. So what did you find?
Dr. Torbjørn Omland:
Yeah, so we found that among these biomarkers, several seem to predict outcome, and the primary end point of this study was to combined end-point of the hospitalization in the ICU, or death. We found that also markers like cardio traponin, BNP, ferritin, and the D-dimer and so forth, in univariable analysis, were very associated with outcome, but when we perform a more comprehensive, mostly variable modeling, then the prognostic value of some of these markers disappeared. In contrast, for GDF-15, it seemed to perform very strongly, both on the baseline sample, and interestingly also it increased in those reaching the primary end-point during the hospitalization. So it provided a very strong and independent information also when we adjusted for clinical risk scores, like the NEWS score. So that was a very pleasant surprise to see that there was one marker that's actually performed so well. The other marker that's also performed well was Ferritin.
Dr. Carolyn Lam:
Very interesting, and so the new score being the National Early Warning Score. Thank you. Verra, I really love to bring in your thoughts. I mean, could you take us behind the scenes with the editors? What did you think when you saw this paper?
Dr. Vera Bittner:
As you know, I mean, a lot of journals have been inundated by COVID papers, and so this one stuck out to us, because it's the first time that we had seen that anybody linked GDF-15 to a COVID population, even though it has been out in the literature for ACS, and in my prognostication, and in a healthy populations, and in chronic coronary disease populations, heart failure, and so on. So this is the first time that we've seen it applied there.
Dr. Vera Bittner:
Then I would echo some of the things that Torbjorn said, that we were also impressed, that it was prospective, because when you look at some of the other biomarker studies, what was prognostic in one with then not shake out the other one, because either different variables were included in the models, because the population's differed. So to have something that was representative of the population that was actually admitted to this, Norwegian Academic Hospital, stood out to us. So we're excited to get this paper basically for circulation, and hope that it also will be impetus for future research.
Dr. Carolyn Lam:
Thank you so much for sharing that end for helping us publish such a beautiful paper. Did you have some questions for two of your own?
Dr. Vera Bittner:
Yeah. So what stuck out to me is that you had this a whole crew of biomarkers, and then when you looked ultimately at the final model, there were two that were standing out, that was ferritin, and it was the GDF-15, and then when I looked at your graph, it looks like not only did these biomarkers measure different contrasts, but their time-course also seemed to be different, and so I was just wondering whether you had thought about, maybe using these to joint the model outcome, and whether we might even be able to get more information that way.
Dr. Torbjørn Omland:
I think that's an excellent suggestion, and as you correctly pointed out, they do have different sort of profiles and ferritin being an acute phase reactant, having various sort of dramatic early rise whereas we see that GDF-15 increased progressively during the course of hospitalization in the most severe patients. I think when combining them, is actually a great IMT that we should look further into.
Dr. Carolyn Lam:
Very nice. Torbjorn, if I could, I've got a couple of questions too. So 123 patients, 35 of whom had the primary outcome, right? So that may be sort of seen as, is this too small? and they're all hospitalized patients. So could I ask, what do you predict maybe seen in a larger population or outside of Norway or in a non-hospitalized population?
Dr. Torbjørn Omland:
So as you say, we were early with this report, but since it was submitted, there has been a couple of smaller studies that seemed to confirm our results. So that is reassuring, but of course we would like to have studied this in logical patients. We are in touch with the other biobank samples that could possibly confirm the data. So that's one obvious step. Then it's very interesting, as you say, could we sort of expand this to also apply to non-hospitalized patients? I think that it would be a very interesting hypothesis to test, and I think there's still a pretty good rationale for this.
Dr. Torbjørn Omland:
It's interesting that the insoluble group actually showed a correlation that when the soluble ST2 concentrations and GDF-15. So there might be that those with more susceptibility to COVID infections, actually, I thought that, that is actually reflected by GDF-15 concentrations, but the challenge is how to sort of get a representative non-hospitalized population, but interestingly, I was approached by some of the hospital staff that actually are in contact with general practitioners, and wanted sort of implement this test also for this group.
Dr. Carolyn Lam:
So Verra, we're really grateful that Allan Jaffe was working with you in managing this beautiful paper, and if you don't mind me cheekily paraphrasing that you said you might channel him, if you could, what would the channeled Allan Jaffe perhaps say about what's needed in this whole biomarkers fear in COVID-19?
Dr. Vera Bittner:
Hopefully, many. A channeling element is obviously difficult, because he is such an incredible expert on biomarkers that I can't even pretend to be able to see, that you might be thinking, but it seems to me that one thing that we could all agree on is that it would be really exciting if something like the: get with the guidelines COVID registry, could decide to measure this marker perspectively in the participating hospitals, for example.
Dr. Vera Bittner:
Then be able to look at this in a much, much larger population. I mean, especially with different ethnic backgrounds as well. I mean, I noticed actually to my surprise that, this Norwegian study how to fairly high proportion of Asians in the sample, but that may not be the ethnic distribution that we might see in different regions of the US, or different regions of the world. So it would be really nice to incorporate the measurement of this biomarker in much larger datasets. So things can be explored a bit further.
Dr. Carolyn Lam:
That's excellent, and Torbjorn, if you could channel Allan. What would you say?
Dr. Torbjørn Omland:
That's a difficult path, but absolutely just to me what Verra said. Then I think the importance of prospective studies in the COVID biomarker field, I think is our at most importance.
Dr. Carolyn Lam:
I think on behalf of both Torbjorn and I, and in fact everyone in circulation. Thank you, Verra for the amazing work that you and your team do for circulation as well. Thank you so much for making the time to share your thoughts today and thank you for that beautiful, beautiful paper both of you. Thank you. (singing). Listeners you've been listening to Circulation on the Run. Thank you for joining us from Greg and I. Don't forget to tune in again next week.
Dr. Greg Hundley:
This program is copyright, the American Heart Association 2020.