Association of vitamin D receptor BsmI (rs1544410) gene polymorphism with the intact parathyroid hormone (iPTH) level among patients with end-stage renal disease

Effects of genetic variants on serum parathyroid hormone in hyperparathyroidism and end-stage renal disease patients: A systematic review and meta-analysis

BACKGROUND

Parathyroid hormone (PTH) is one of the principal regulators of calcium homeostasis, crucial for normal functioning of the kidneys, bones, heart, and nervous system. Different pathologic conditions can affect serum PTH level resulting in hyperparathyroidism or hypoparathyroidism. Our study assessed the association of previously reported polymorphisms with the level of PTH (expressed in pg/mL) among individuals with different pathologic conditions affecting PTH level.

METHODS

We searched Web of Science, MEDLINE, and Scopus to identify relevant articles published up to July 2017. The search yielded 6967 publications of which 44 fulfilled the inclusion criteria. We conducted meta-analyses for calcium-sensing receptor gene (CaSR) rs1801725 polymorphism in patients with primary hyperparathyroidism and vitamin D receptor gene (VDR) rs1544410 polymorphism in patients with end-stage renal disease (ESRD).

RESULTS

None of the polymorphisms were significantly associated with PTH levels in the overall population. In subgroup analysis by ethnicity for VDR rs1544410 gene polymorphism, we found significant differences under dominant model (SMD: -0.18 [-0.32, -0.05], P < .01) and AA versus GG comparison (SMD: -0.29 [-0.52, -0.06], P < .01) in Asian patients with ESRD, while nominally significant results (P < .05) were observed for AG versus GG and AA versus GG comparisons in European individuals with ESRD.

CONCLUSION

Scientific evidence of genetic association of serum PTH level among individuals with different pathologic conditions remains deficient and published results provide weak evidence. Further well-conducted studies on larger sample sets designed according to evidence-based principles are warranted to assure clinically applicable findings.

Effects of vitamin D combined with pioglitazone hydrochloride on bone mineral density and bone metabolism in Type 2 diabetic nephropathy

The study aims to investigate the effect of vitamin D (VD) combined with pioglitazone hydrochloride (PIO) on bone mineral density (BMD) and bone metabolism in patients with Type 2 diabetic nephropathy (T2DN). T2DN patients were selected and assigned into mild, moderate, and severe groups. In each group, three therapy regimens (VD, PIO, and VD plus PIO) were administered. X-ray absorptiometry was used to measure BMD. Intact parathyroid hormone (iPTH) and 25-hydroxyvitamin D3 (25-OH-VD3) were measured by chemiluminescence meter. ELISA was applied to detect levels of osteoprotegerin (OPG), bone gla protein (BGP), C-terminal telopeptides of type I collagen (β-CTX), procollagen type I N-propeptide (PINP), pyridinoline (Pyr), and deoxypyridinoline (D-Pyr). Compared with the mild group, T2DN patients in the moderate and severe groups had longer course of disease and higher levels of total cholesterol (TC), triglyceride (TG), serum phosphorus, fasting plasma glucose (FPG), glycosylated hemoglobin (HbAlc) and creatine (Cr), and lower blood calcium. The BMD in different parts increased among the mild, moderate, and severe groups, and the highest BMD was found after VD plus PIO treatment. OPG, iPTH, BGP, β-CTX, Pyr/Cr, and D-Pyr/Cr levels were reduced, while 25-OH-VD3 and PINP levels were elevated among three groups after different treatments, and the most obvious change was observed after VD plus PIO treatment. Our findings indicate that VD combined with PIO may be more effective in improving BMD and bone metabolism than VD or PIO alone in the treatment of T2DN patients, especially for T2DN patients with mild disease.

Levels of vitamin D receptor and CYP24A1 in patients with end-stage renal disease

OBJECTIVE

This study was performed to detect the expression of vitamin D receptor (VDR) and cytochrome P450, family 24, subfamily A, polypeptide 1 (CYP24A1) in 24 end stage renal disease (ESRD) patients and 24 healthy controls.

METHOD

In this study, 24 ESRD patients and 24 healthy controls were included.

RESULTS

In our study, the levels of VDR in patients with ESRD were reduced when compared with those from healthy controls (5.20±0.32 vs 8.59±1.03; P<0.01). However, the levels of CYP24A1 in ESRD patients were increased than those from healthy controls (50.18±21 vs 7.78±1.31; P<0.01). Correlation analysis showed that VDR levels were negatively correlated with CYP24A1 (r=-0.723; P<0.01).

CONCLUSION

VDR levels were reduced and CYP24A1 levels were increased in patients with ESRD, and VDR levels were negatively correlated with CYP24A1.