Insulin resistance and left ventricular hypertrophy in end-stage renal disease: association between the ENPP1 gene and left ventricular concentric remodelling.

BACKGROUND: Left ventricular hypertrophy (LVH) and insulin resistance (IR) are frequent complications of end-stage renal disease (ESRD). The ectonucleotide pyrophosphatase phosphodiesterase 1 (ENPP1) gene, whose variability has been repeatedly associated with IR, codes for a membrane glycoprotein which inhibits insulin-receptor signalling. METHODS: We investigated the relationship of ENPP1 variability, as indicated by 10 single nucleotide polymorphisms (SNPs) representative of the gene haploblock structure, with left ventricular mass and geometry (by echocardiography) in an ethnically homogeneous series of 238 Caucasian ESRD patients. RESULTS: ENPP1 rs1974201 and rs9402349 polymorphisms were coherently associated (P ranging from 0.04 to 0.005) with indicators of left ventricular (LV) myocardial hypertrophy (mean wall thickness) and concentric remodelling (relative wall thickness and LV mass-to-volume ratio) but unrelated with the cavitary component of the LV (left ventricular end-diastolic volume). As compared to individuals carrying the alternative genotypes, the risk of LV concentric remodelling was approximately doubled in major allele homozygous for rs1974201 [odds ratio (OR) of GG versus GC + CC: 2.31, 95% confidence interval (CI): 1.30-4.12, P = 0.004] and rs9402349 (OR of AA versus AC + CC: 1.91, 95% CI: 1.02-3.56, P = 0.04) polymorphisms. CONCLUSIONS: Coherent associations exists between echocardiographic parameters of LV myocardial hypertrophy and concentric remodelling and ENPP1 variability in ESRD patients. These data support the hypothesis that IR is a relevant factor in the pathogenesis of myocardiopathy in this population.