Vitamin D Receptor Genetics on Extracellular Matrix Biomarkers and Hemodynamics in Systolic Heart Failure

Introduction: Vitamin D deficiency has been associated with the development of myocardial hypertrophy and inflammation. These findings suggest that vitamin D status and vitamin D receptor (VDR) genomics may play a role in myocardial fibrosis. The aim of this pilot study was to determine the association between vitamin D levels, VDR polymorphisms, and biomarkers of left ventricular remodeling and hemodynamics. Methods: In a cross-sectional pilot study, patients with ejection fraction (EF) <40% (and New York Heart Association >= II) undergoing right heart catheterization were included in the study. Blood was collected for determination of 25-hydroxyvitamin D level (antibody competitive immunoassay), VDR genotypes (Bsml, Apal, Taql, and Fokl), and biomarkers (N-terminal propeptide of collagen type III [PIIINP], matrix metalloproteinase 2, and galectin 3). The vitamin D genotypes were determined through the use of pyrosequencing. Results: A total of 30 patients with a mean EF of 17% +/- 8% were enrolled. There was a significant association between the Bsml C allele, Apal G allele, and Taql A allele, which formed a haplotype block (CGA) for analysis. There were no differences in baseline parameters between patients with the VDR haplotype block (n = 20) and those without (n = 10). Individual genotypes were not associated with any biomarker or hemodynamics. Patients with the CGA haplotype demonstrated significantly higher log PIIINP values (1.74 +/- 0.32 mcg/mL vs 1.36 +/- 0.31 mcg/mL, P = .0041). When evaluating vitamin D levels below and above the median level (19 ng/mL), there was no significant difference between these 2 groups in regard to biomarker levels for left ventricular remodeling. Conclusion: This study has shown that a biomarker for collagen type III synthesis, PIIINP, was associated with the CGA haplotype of Bsml, Apal, and Taql single nucleotide polymorphisms on the VDR. These findings suggest that VDR genetics may play a role in myocardial fibrosis in patients with systolic heart failure.