👤 Athanasia Stathopoulou

Apolipoprotein B (apoB) is a recognized risk factor for acute coronary syndrome (ACS); however, its prognostic value in secondary prevention and superiority over other lipid biomarkers, especially in younger populations, remains uncertain. To investigate whether elevated baseline apoB predicts recurrent cardiovascular events in patients who experienced an ACS at ≤40 years of age and compare its incremental predictive value with that of other lipid biomarkers. We recruited 405 consecutive patients who survived an ACS at ≤40 years of age. Clinical endpoints included major adverse cardiovascular events (MACE): cardiac death, readmission for ACS or ventricular arrhythmias, ischemic stroke, and coronary revascularization due to clinical deterioration. The association between baseline lipid biomarkers and recurrent MACE risk was assessed using multivariable Cox regression. Model performance was evaluated based on discrimination and reclassification. Of 378 young ACS survivors (33.7 ± 4.3 years) with follow-up data, 139 (36.8%) experienced a MACE over a median 8-year (5.2-12.5 years) follow-up. Elevated baseline apoB was independently associated with a higher risk of recurrent MACE (hazard ratio per 10 mg/dL: 1.082, P= .007). This association remained significant even after additionally accounting for low-density lipoprotein cholesterol (LDL-C) or non-high-density lipoprotein cholesterol (non-HDL-C). Conversely, apoB adjustment attenuated the LDL-C and non-HDL-C associations. Compared with LDL-C and non-HDL-C, apoB was associated with greater risk of recurrent MACE, and upon addition to conventional cardiovascular risk factors, yielded the greatest improvement in discrimination and reclassification. Baseline apoB may act as a driver for long-term recurrence of MACE in very young ACS survivors, highlighting its potential clinical utility to improve risk stratification beyond traditional lipid measurements. Show less

Lipoprotein(a) [Lp(a)] is a causal risk factor for cardiovascular disease, and it is particularly associated with premature acute coronary syndrome (ACS). We investigated whether elevated Lp(a) can predict recurrent cardiovascular events in patients who experienced their first ACS less than or equal to 40 years of age. Within the STudy of eArly Myocardial INfArction registry, we recruited 405 consecutive patients who survived their first ACS less than or equal to 40 years of age; of them 378 had complete follow-up data. Clinical endpoint was the development of major adverse cardiovascular events (MACE; i.e. cardiac death, readmission for ACS or malignant ventricular arrhythmias, ischemic stroke, or coronary revascularization due to clinical deterioration). Multi-adjusted Cox regression was used to assess the association between Lp(a) and first recurrent MACE risk. Of the 378 ACS survivors (33.7 ± 4.3 years), 139 (36.8%) experienced a MACE over a median 8-year (5.2-12.5 years) follow-up. Elevated Lp(a) showed a borderline independent association with higher recurrent MACE [hazard ratio per 1 mg/dl: 1.004, 95% confidence interval (CI): 0.999-1.009, P = 0.051]. Moreover, patients with baseline Lp(a) levels greater than or equal to 50 mg/dl had 82.6% higher risk of MACE as compared with those below (hazard ratio 1.826, 95% CI: 1.141-2.925, P = 0.012); similarly, patients with Lp(a) ≥ 70 mg/dl had 118% higher risk as compared with those below (hazard ratio 2.180, 95% CI: 1.330-3.573, P = 0.002). Elevated Lp(a) concentrations demonstrate an independent association with recurrent MACE among very young ACS survivors. Until targeted Lp(a)-lowering treatments become clinically available, an aggressive lipid-lowering approach may be warranted to partially attenuate Lp(a)-related residual cardiovascular risk. Show less

Closed spinal dysraphisms are poorly understood malformations classified as neural tube (NT) defects. Several, including terminal myelocystocele, affect the distal spine. We have previously identified a NT closure-initiating point, Closure 5, in the distal spine of mice. Here, we document equivalent morphology of the caudal-most closing posterior neuropore (PNP) in mice and humans. Closure 5 forms in a region of active FGF signalling, and pharmacological FGF receptor blockade impairs its formation in cultured mouse embryos. Conditional genetic deletion of Fgfr1 in caudal embryonic tissues with Cdx2Cre diminishes neuroepithelial proliferation, impairs Closure 5 formation and delays PNP closure. After closure, the distal NT of Fgfr1-disrupted embryos dilates to form a fluid-filled sac overlying ventrally flattened spinal cord. This phenotype resembles terminal myelocystocele. Histological analysis reveals regional and progressive loss of SHH- and FOXA2-positive ventral NT domains, resulting in OLIG2 labelling of the ventral-most NT. The OLIG2 domain is also subsequently lost, eventually producing a NT that is entirely positive for the dorsal marker PAX3. Thus, a terminal myelocystocele-like phenotype can arise after completion of NT closure with localised spinal mis-patterning caused by disruption of FGFR1 signalling. Show less

Vascular endothelial growth factor (VEGF) is an angiogenic and neurotrophic factor, secreted by endothelial cells, known to impact various physiological and disease processes from cancer to cardiovascular disease and to be pharmacologically modifiable. We sought to identify novel loci associated with circulating VEGF levels through a genome-wide association meta-analysis combining data from European-ancestry individuals and using a dense variant map from 1000 genomes imputation panel. Six discovery cohorts including 13,312 samples were analyzed, followed by in-silico and de-novo replication studies including an additional 2,800 individuals. A total of 10 genome-wide significant variants were identified at 7 loci. Four were novel loci (5q14.3, 10q21.3, 16q24.2 and 18q22.3) and the leading variants at these loci were rs114694170 (MEF2C, P = 6.79 x 10(-13)), rs74506613 (JMJD1C, P = 1.17 x 10(-19)), rs4782371 (ZFPM1, P = 1.59 x 10(-9)) and rs2639990 (ZADH2, P = 1.72 x 10(-8)), respectively. We also identified two new independent variants (rs34528081, VEGFA, P = 1.52 x 10(-18); rs7043199, VLDLR-AS1, P = 5.12 x 10(-14)) at the 3 previously identified loci and strengthened the evidence for the four previously identified SNPs (rs6921438, LOC100132354, P = 7.39 x 10(-1467); rs1740073, C6orf223, P = 2.34 x 10(-17); rs6993770, ZFPM2, P = 2.44 x 10(-60); rs2375981, KCNV2, P = 1.48 x 10(-100)). These variants collectively explained up to 52% of the VEGF phenotypic variance. We explored biological links between genes in the associated loci using Ingenuity Pathway Analysis that emphasized their roles in embryonic development and function. Gene set enrichment analysis identified the ERK5 pathway as enriched in genes containing VEGF associated variants. eQTL analysis showed, in three of the identified regions, variants acting as both cis and trans eQTLs for multiple genes. Most of these genes, as well as some of those in the associated loci, were involved in platelet biogenesis and functionality, suggesting the importance of this process in regulation of VEGF levels. This work also provided new insights into the involvement of genes implicated in various angiogenesis related pathologies in determining circulating VEGF levels. The understanding of the molecular mechanisms by which the identified genes affect circulating VEGF levels could be important in the development of novel VEGF-related therapies for such diseases. Show less

Cardiac myosin-binding protein C (cMyBP-C) regulates actin-myosin interaction and thereby cardiac myocyte contraction and relaxation. This physiologic function is regulated by cMyBP-C phosphorylation. In our study, reduced site-specific cMyBP-C phosphorylation coincided with increased S-glutathiolation in ventricular tissue from patients with dilated or ischemic cardiomyopathy compared to nonfailing donors. We used redox proteomics, to identify constitutive and disease-specific S-glutathiolation sites in cMyBP-C in donor and patient samples, respectively. Among those, a cysteine cluster in the vicinity of the regulatory phosphorylation sites within the myosin S2 interaction domain C1-M-C2 was identified and showed enhanced S-glutathiolation in patients. In vitro S-glutathiolation of recombinant cMyBP-C C1-M-C2 occurred predominantly at Cys(249), which attenuated phosphorylation by protein kinases. Exposure to glutathione disulfide induced cMyBP-C S-glutathiolation, which functionally decelerated the kinetics of Ca(2+)-activated force development in ventricular myocytes from wild-type, but not those from Mybpc3-targeted knockout mice. These oxidation events abrogate protein kinase-mediated phosphorylation of cMyBP-C and therefore potentially contribute to the reduction of its phosphorylation and the contractile dysfunction observed in human heart failure.-Stathopoulou, K., Wittig, I., Heidler, J., Piasecki, A., Richter, F., Diering, S., van der Velden, J., Buck, F., Donzelli, S., Schröder, E., Wijnker, P. J. M., Voigt, N., Dobrev, D., Sadayappan, S., Eschenhagen, T., Carrier, L., Eaton, P., Cuello, F. S-glutathiolation impairs phosphoregulation and function of cardiac myosin-binding protein C in human heart failure. Show less

Hypertrophic cardiomyopathy (HCM) is often accompanied by increased myofilament Ca(2+) sensitivity and diastolic dysfunction. Recent findings indicate increased late Na(+) current density in human HCM cardiomyocytes. Since ranolazine has the potential to decrease myofilament Ca(2+) sensitivity and late Na(+) current, we investigated its effects in an Mybpc3-targeted knock-in (KI) mouse model of HCM. Unloaded sarcomere shortening and Ca(2+) transients were measured in KI and wild-type (WT) cardiomyocytes. Measurements were performed at baseline (1 Hz) and under increased workload (30 nM isoprenaline (ISO), 5 Hz) in the absence or presence of 10 µM ranolazine. KI myocytes showed shorter diastolic sarcomere length at baseline, stronger inotropic response to ISO, and drastic drop of diastolic sarcomere length under increased workload. Ranolazine attenuated ISO responses in WT and KI cells and prevented workload-induced diastolic failure in KI. Late Na(+) current density was diminished and insensitive to ranolazine in KI cardiomyocytes. Ca(2+) sensitivity of skinned KI trabeculae was slightly decreased by ranolazine. Phosphorylation analysis of cAMP-dependent protein kinase A-target proteins and ISO concentration-response measurements on muscle strips indicated antagonism at β-adrenoceptors with 10 µM ranolazine shifting the ISO response by 0.6 log units. Six-month treatment with ranolazine (plasma level >20 µM) demonstrated a β-blocking effect, but did not reverse cardiac hypertrophy or dysfunction in KI mice. Ranolazine improved tolerance to high workload in mouse HCM cardiomyocytes, not by blocking late Na(+) current, but by antagonizing β-adrenergic stimulation and slightly desensitizing myofilaments to Ca(2+). This effect did not translate in therapeutic efficacy in vivo. Show less

More than 350 individual MYPBC3 mutations have been identified in patients with inherited hypertrophic cardiomyopathy (HCM), thus representing 40–50% of all HCM mutations, making it the most frequently mutated gene in HCM. HCM is considered a disease of the sarcomere and is characterized by left ventricular hypertrophy, myocyte disarray and diastolic dysfunction. MYBPC3 encodes for the thick filament associated protein cardiac myosin-binding protein C (cMyBP-C), a signaling node in cardiac myocytes that contributes to the maintenance of sarcomeric structure and regulation of contraction and relaxation. This review aims to provide a succinct overview of how mutations in MYBPC3 are considered to affect the physiological function of cMyBP-C, thus causing the deleterious consequences observed inHCM patients. Importantly, recent advances to causally treat HCM by repairing MYBPC3 mutations by gene therapy are discussed here, providing a promising alternative to heart transplantation for patients with a fatal form of neonatal cardiomyopathy due to bi-allelic truncating MYBPC3 mutations. Show less