👤 Rasmani Hazra

Patients with cardiomyopathies are a heterogeneous group of patients who experience high morbidity and mortality. Early cardiac assessment and intervention with access to genetic counselling in a multidisciplinary Cardiomyopathy Clinic may improve outcomes and prevent progression to advanced heart failure. Our prospective cohort study was conducted at a multidisciplinary Cardiomyopathy Clinic with 421 patients enrolled (42.5% female, median age 58 years), including 224 patients with dilated cardiomyopathy (DCM, 42.9% female, median age 57 years), 72 with hypertrophic cardiomyopathy (HCM, 43.1% female, median age 60 years), 79 with infiltrative cardiomyopathy (65.8% female, median age 70 years) and 46 who were stage A/at risk for genetic cardiomyopathy (54.3% female, median age 36 years). Patients were seen in follow-up at a median of 18 months. A pathogenic/likely pathogenic variant was identified in 28.5% of the total cohort, including 33.3% of the DCM cohort (28% TTN mutations) and 34.1% of the HCM cohort (60% MYBPC3 and 20% MYH7) who underwent genetic testing. The use of angiotensin-converting enzyme inhibitors/angiotensin receptor blockers/angiotensin receptor neprilysin inhibitor (48.3-69.5% of total cohort, P < 0.001), β-blockers (58.4-72.4%, P < 0.001), mineralocorticoid receptor antagonists (33.9-41.4%, P = 0.0014) and sodium/glucose cotransporter-2 inhibitors (5.3-27.9%, P < 0.001) all increased at follow-up. Precision-based therapies were also implemented, including tafamidis for transthyretin amyloidosis (n = 21), enzyme replacement therapy for Fabry disease (n = 14) and mavacamten (n = 4) for HCM. Optimization of medications and devices resulted in improvements in left ventricular ejection fraction (LVEF) from 27% to 43% at follow-up for DCM patients with reduced LVEF at baseline (P < 0.001) and reduction in left ventricular mass index (LVMI) from 156 g/m Our study demonstrates that a multidisciplinary cardiomyopathy clinic can improve the clinical profiles of patients with diverse genetic cardiomyopathies. Show less

We determined the functional role of the Sertoli cell glucocorticoid receptor (GR) in vivo using a transgenic Cre-loxP approach to conditionally disrupt GR expression. Sertoli cell GR knockout (SCGRKO) was shown by absent Sertoli cell-specific GR immunolocalization and reduced levels of glucocorticoid-responsive Stc1 and Tsc22d3 mRNA in SCGRKO relative to control testes. Adult SCGRKO testes exhibited distinct morphological changes, including reduced seminiferous tubular lumen formation, decreased total Sertoli cell numbers, and parallel reductions in meiotic spermatocyte and postmeiotic spermatid numbers. Conversely, tubular diameter was increased and testis size was normal in SCGRKO males. Decreased serum FSH and testicular Fshr mRNA levels were consistent with reduced Sertoli cell number. Adult SCGRKO testes also displayed atypical germ cells and interstitial focal accumulations of hypertrophic lipid-laden, immature-like Leydig cells. Circulating LH, and testicular Lhr mRNA, testosterone, dihydrotestosterone, and 3α/3β-diol levels were all reduced in mature SCGRKO mice, whereas serum testosterone and dihydrotestosterone levels remained normal. Moreover, Sertoli cell GR disruption caused differential changes to steroidogenic enzyme transcripts, with down-regulated testicular Cyp11a1 contrasting with up-regulated Hsd17b3 expression. Reduced SCGRKO testicular expression of Hsd11b2, encoding an enzyme for corticosterone inactivation, supports a dynamic coupling between Hsd11b and androgen production. Our novel SCGRKO model has revealed that Sertoli cell-mediated GR actions support normal testicular function. Sertoli cell GR is required to maintain normal testicular Sertoli/germ cell numbers and circulating gonadotropin levels, as well as optimal Leydig cell maturation and steroidogenesis, providing new insight into gluocorticoid-mediated impact on male reproduction. Show less

The strong observational association between total homocysteine (tHcy) concentrations and risk of coronary artery disease (CAD) and the null associations in the homocysteine-lowering trials have prompted the need to identify genetic variants associated with homocysteine concentrations and risk of CAD. We tested whether common genetic polymorphisms associated with variation in tHcy are also associated with CAD. We conducted a meta-analysis of genome-wide association studies (GWAS) on tHcy concentrations in 44,147 individuals of European descent. Polymorphisms associated with tHcy (P < 10(⁻⁸) were tested for association with CAD in 31,400 cases and 92,927 controls. Common variants at 13 loci, explaining 5.9% of the variation in tHcy, were associated with tHcy concentrations, including 6 novel loci in or near MMACHC (2.1 × 10⁻⁹), SLC17A3 (1.0 × 10⁻⁸), GTPB10 (1.7 × 10⁻⁸), CUBN (7.5 × 10⁻¹⁰), HNF1A (1.2 × 10⁻¹²)), and FUT2 (6.6 × 10⁻⁹), and variants previously reported at or near the MTHFR, MTR, CPS1, MUT, NOX4, DPEP1, and CBS genes. Individuals within the highest 10% of the genotype risk score (GRS) had 3-μmol/L higher mean tHcy concentrations than did those within the lowest 10% of the GRS (P = 1 × 10⁻³⁶). The GRS was not associated with risk of CAD (OR: 1.01; 95% CI: 0.98, 1.04; P = 0.49). We identified several novel loci that influence plasma tHcy concentrations. Overall, common genetic variants that influence plasma tHcy concentrations are not associated with risk of CAD in white populations, which further refutes the causal relevance of moderately elevated tHcy concentrations and tHcy-related pathways for CAD. Show less

Endothelial progenitor cells (EPCs), critical for mediating vascular repair, are dysfunctional in a hyperglycemic and/or hypercholesterolemic environment. Their dysfunction contributes to the progression of diabetic macro- and microvascular complications. Activation of "cholesterol-sensing" nuclear receptors, the liver X receptors (LXRα/LXRβ), protects against atherosclerosis by transcriptional regulation of genes important in promoting cholesterol efflux and inhibiting inflammation. We hypothesized that LXR activation with a synthetic ligand would correct diabetes-induced EPC dysfunction and improve diabetic retinopathy. Studies were performed in streptozotocin (STZ)-injected DBA/2J mice fed a high-fat Western diet (DBA/STZ/WD) and treated with the LXR agonist GW3965 and in LXRα(-/-), LXRβ(-/-), and LXRα/β(-/-) mice. Retinas were evaluated for number of acellular capillaries and glial fibrillary acidic protein (GFAP) immunoreactivity. Bone marrow EPCs were analyzed for migratory function and gene expression. Compared with vehicle-treated DBA/STZ/WD mice, GW3965 treated mice showed fewer acellular capillaries and reduced GFAP expression. These mice also exhibited enhanced EPC migration and restoration of inflammatory and oxidative stress genes toward nondiabetic levels. LXRα(-/-), LXRβ(-/-), and LXRα/β(-/-) mice developed acellular capillaries and EPC dysfunction similar to the DBA/STZ/WD mice. These studies support a key role for LXR in retinal and bone marrow progenitor dysfunction associated with type 1 diabetes. LXR agonists may represent promising pharmacologic targets for correcting retinopathy and EPC dysfunction. Show less