Association between preoperative peripheral blood mononuclear cell gene expression profiles, early postoperative organ function recovery potential and long-term survival in advanced heart failure patients undergoing mechanical circulatory support

An Exercise Immune Fitness test to unravel mechanisms of post-acute sequelae of COVID-19

The Post-Acute Sequelae of COVID-19 (PASC) Syndrome is a debilitating syndrome with onset three months post COVID-19 infection, marked by the presence of fatigue, headache, cognitive dysfunction, post-exertional malaise, orthostatic intolerance, and dyspnea that is clinically relevant and is at least as severe as fatigue in several other clinical conditions, including cancer. The onset, progression, and symptom profile of PASC patients have considerable overlap with Myalgic-Encephalopathy/Chronic Fatigue Syndrome (ME/CFS). In people with ME/CFS, exercise (and other types of exertion) can cause serious setbacks and deterioration in function. Post-exertional malaise (PEM) appears to be a common and a significant challenge for the majority of this patient group. Of the nearly 24 million adults in the U.S. who currently have long COVID, more than 80% are having some trouble carrying out daily activities. Mechanisms of PACS remain poorly understood. While multi-omic information gathered at the time of acute COVID-19 onset may help predict long COVID outcomes, we here propose to test the hypothesis that additional molecular immunological information collected during standardized exercise-testing for cardio-respiratory fitness after recovery from acute COVID-19 can be used to improve the understanding of mechanisms of PASC.

Beta-adrenergic receptors gene polymorphisms are associated with cardiac contractility and blood pressure variability

Beta-adrenergic receptors (beta-ARs) play a pivotal role in the cardiovascular regulation. In the human heart beta1- and beta2-ARs dominate in atria as well as in ventricle influencing heart rate and myocardial contractility. Some single nucleotide polymorphisms (SNPs) of beta-ARs might influence cardiovascular function. However, the influence of beta-AR genes SNPs on hemodynamic parameters at rest and their reactivity under stress is still not well known. We aimed to explore the associations between four selected beta-ARs gene polymorphisms and selected cardiovascular measures in eighty-seven young healthy subjects. While in beta1-AR polymorphism rs1801252 no significant association was observed, second beta1-AR polymorphism rs1801253 was associated with decreased cardiac output and cardiac index during all phases and with decreased flow time corrected and ejection time index at rest and during mental arithmetics. Polymorphism rs1042713 in beta2-AR was associated with alterations in blood pressure variability at rest and during head-up-tilt, while rs1042714 was associated predominantly with decreased parameters of cardiac contractility at rest and during mental arithmetics. We conclude that complex analysis of various cardiovascular characteristics related to the strength of cardiac contraction and blood pressure variability can reveal subtle differences in cardiovascular sympathetic nervous control associated with beta-ARs polymorphisms.

The evolution of patient-specific precision biomarkers to guide personalized heart-transplant care

Introduction

In parallel to the clinical maturation of heart transplantation over the last 50 years, rejection testing has been revolutionized within the systems biology paradigm triggered by the Human Genome Project.

Areas Covered

We have co-developed the first FDA-cleared diagnostic and prognostic leukocyte gene expression profiling biomarker test in transplantation medicine that gained international evidence-based medicine guideline acceptance to rule out moderate/severe acute cellular cardiac allograft rejection without invasive endomyocardial biopsies. This work prompted molecular re-classification of intragraft biology, culminating in the identification of a pattern of intragraft myocyte injury, in addition to acute cellular rejection and antibody-mediated rejection. This insight stimulated research into non-invasive detection of myocardial allograft injury. The addition of a donor-organ specific myocardial injury marker based on donor-derived cell-free DNA further strengthens the non-invasive monitoring concept, combining the clinical use of two complementary non-invasive blood-based measures, host immune activity-related risk of acute rejection as well as cardiac allograft injury.

Expert Opinion

This novel complementary non-invasive heart transplant monitoring strategy based on leukocyte gene expression profiling and donor-derived cell-free DNA that incorporates longitudinal variability measures provides an exciting novel algorithm of heart transplant allograft monitoring. This algorithm's clinical utility will need to be tested in an appropriately designed randomized clinical trial which is in preparation.

The aging transplant population and immunobiology: any therapeutic implication?

PURPOSE OF REVIEW

The aim of this review is to describe the latest investigations into the immunobiology of aging and the potential impact on outcomes after mechanical circulatory support implantation and heart transplantation. This information is relevant given the growing numbers of older patients with heart failure undergoing evaluation for mechanical circulatory support device (MCSD) or heart transplantation.

RECENT FINDINGS

A host of aging-associated aspects of immune dysfunction have been described in the general population including T-cell senescence, exhaustion, and terminal dedifferentiation, as well as impaired function of innate immune cells. Another important consequence of T-cell senescence is inflammation, which is known to have a strong relationship with both heart failure and frailty in older patients. Recent data on the association between T-cell and monocyte phenotypes as well as evaluation of gene expression and adverse outcomes after MCSD suggests the potential value of immunologic assessment of MCSD and heart transplant candidates and recipients. Measurement of physical frailty represents another avenue for patient evaluation that may complement immunologic assessment. Determination of immune dysfunction and frailty prior to transplantation may have implications for choice of induction and dosing of maintenance immunosuppression.

SUMMARY

As the age of transplant and MCSD candidates and recipients continues to increase, it is important for providers to recognize the potential impact of aging-associated immune dysfunction and how it may influence candidate selection, postintervention monitoring, and adjustment of immunosuppression.

Comparing NGS and NanoString platforms in peripheral blood mononuclear cell transcriptome profiling for advanced heart failure biomarker development

In preparation to create a clinical assay that predicts 1-year survival status of advanced heart failure (AdHF) patients before surgical/interventional therapies and to select the appropriate clinical assay platform for the future assay, we compared the properties of next generation sequencing (NGS) used in the gene discovery phase to the NanoString platform used in the clinical assay development phase. In 25 AdHF patients in a tertiary academic medical center from 2015 to 2016, PBMC samples were collected and aliquoted for NGS RNA whole transcriptome sequencing and compared to 770 genes represented on NanoString's PanCancer IO 360 Gene Expression research panel. Prior to statistical analysis, NanoString and NGS expression values were log transformed. We computed Pearson correlation coefficients for each sample, comparing gene expression values between NanoString and NGS across the set of matched genes and for each of the matched genes across the set of samples. Genes were grouped by average NGS expression, and the NanoString-NGS correlation for each group was computed. Out of 770 genes from the NanoString panel, 734 overlapped between both platforms and showed high intrasample correlation. Within an individual sample, there was an expression-level dependent correlation between both platforms. The low- vs. intermediate/high-expression groups showed NGS average correlation 0.21 vs. 0.58-0.68, respectively, and NanoString average correlation 0.07-0.34 vs. 0.59-0.70, respectively. NanoString demonstrated high reproducibility (R 2 > 0.99 for 100 ng input), sensitivity (probe counts between 100 and 500 detected and quantified), and robustness (similar gene signature scores across different RNA input concentrations, cartridges, and outcomes). Data from NGS and NanoString were highly correlated. These platforms play a meaningful, complementary role in the biomarker development process.

Short-Term Therapies for Treatment of Acute and Advanced Heart Failure-Why so Few Drugs Available in Clinical Use, Why Even Fewer in the Pipeline?

Both acute and advanced heart failure are an increasing threat in term of survival, quality of life and socio-economical burdens. Paradoxically, the use of successful treatments for chronic heart failure can prolong life but-per definition-causes the rise in age of patients experiencing acute decompensations, since nothing at the moment helps avoiding an acute or final stage in the elderly population. To complicate the picture, acute heart failure syndromes are a collection of symptoms, signs and markers, with different aetiologies and different courses, also due to overlapping morbidities and to the plethora of chronic medications. The palette of cardio- and vasoactive drugs used in the hospitalization phase to stabilize the patient's hemodynamic is scarce and even scarcer is the evidence for the agents commonly used in the practice (e.g. catecholamines). The pipeline in this field is poor and the clinical development chronically unsuccessful. Recent set backs in expected clinical trials for new agents in acute heart failure (AHF) (omecamtiv, serelaxine, ularitide) left a field desolately empty, where only few drugs have been approved for clinical use, for example, levosimendan and nesiritide. In this consensus opinion paper, experts from 26 European countries (Austria, Belgium, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Israel, Italy, The Netherlands, Norway, Poland, Portugal, Russia, Slovenia, Spain, Sweden, Switzerland, Turkey, U.K. and Ukraine) analyse the situation in details also by help of artificial intelligence applied to bibliographic searches, try to distil some lesson-learned to avoid that future projects would make the same mistakes as in the past and recommend how to lead a successful development project in this field in dire need of new agents.

Established and Emerging Roles of Biomarkers in Heart Failure

Heart failure (HF) is a complex syndrome with an enormous societal burden in terms of cost, morbidity, and mortality. Natriuretic peptide testing is now widely used to support diagnosis, prognostication, and management of patients with HF and are incorporated into HF clinical practice guidelines. Beyond the natriuretic peptides, novel biomarkers may supplement traditional clinical and laboratory testing to improve understanding of the complex disease process of HF and possibly to personalize care for those affected through better individual phenotyping. In this review, we will discuss natriuretic peptides and the more novel biomarkers by dividing them into categories based on the major pathophysiologic pathways they represent. Given the complex physiology in HF, it is reasonable to expect that the future of biomarker testing lies in the application of multimarker testing panels, precision medicine to improve HF care delivery, and the use of biomarkers in proteomics and metabolomics to further improve HF care.

Association of pro-inflammatory cytokines and monocyte subtypes in older and younger patients on clinical outcomes after mechanical circulatory support device implantation

Noninvasive immunologic analysis of peripheral blood holds promise for explaining the mechanism of development of adverse clinical outcomes, and may also become a method for patient risk stratification before or after mechanical circulatory support device (MCSD) implantation. Dysregulation of the innate immune system is associated with increased patient age but has yet to be evaluated in the older patient with advanced heart failure undergoing MCSD surgery. Patients pre- and post-MCSD implantation had peripheral blood mononuclear cells (PBMC) and serum isolated. Multiparameter flow cytometry was used to analyze markers of innate cell function, including monocyte subtypes. Multiplex cytokine analysis was performed. MELD-XI and SOFA scores were utilized as surrogate markers of outcomes. Increased levels of pro-inflammatory cytokines including IL-15, TNF-α, and IL-10 were associated with increased MELD-XI and SOFA scores. IL-8, TNF- α, and IL-10 were associated with risk of death after MCSD implantation, even with correction for patient age. Increased frequency of 'classical' monocytes (CD14 + CD16-) were associated with increased MELD-XI and SOFA scores. This suggests that inflammation and innate immune system activation contribute to progression to multiorgan system failure and death after MCSD surgery. Development of noninvasive monitoring of peripheral blood holds promise for biomarker development for candidate selection and patient risk stratification.

A peripheral blood transcriptome biomarker test to diagnose functional recovery potential in advanced heart failure

Heart failure (HF) is a complex clinical syndrome that causes systemic hypoperfusion and failure to meet the body’s metabolic demands. In an attempt to compensate, chronic upregulation of the sympathetic nervous system and renin-angiotensin-aldosterone leads to further myocardial injury, HF progression and reduced O₂ delivery. This triggers progressive organ dysfunction, immune system activation and profound metabolic derangements, creating a milieu similar to other chronic systemic diseases and presenting as advanced HF with severely limited prognosis. We hypothesize that 1-year survival in advanced HF is linked to functional recovery potential (FRP), a novel clinical composite parameter that includes HF severity, secondary organ dysfunction, co-morbidities, frailty, disabilities as well as chronological age and that can be diagnosed by a molecular biomarker.