Vitamin D deficiency is associated with risk of developing peripheral arterial disease in type 2 diabetic patients.

BACKGROUND: The relationship between vitamin D levels and peripheral arterial disease (PAD) remains unclear. We assessed the association of serum 25-hydroxyvitamin D (25(OH)D) levels with the prevalence of PAD in patients with type 2 diabetes mellitus(T2DM). METHODS: A total of 1018 T2DM patients participated in this cross-sectional study. Serum 25(OH)D levels were measured and risk factors of PAD were recorded. PAD was diagnosed as an ankle-brachial index (ABI) < 0.9. RESULTS: The mean age of the diabetic patients was 58.59 ± 11.34 years. Of all the patients, only 20.1% had a 25(OH)D level ≥ 20 ng/mL. Compared to patients without PAD, serum 25(OH)D levels were significantly lower in those with PAD (14.81 ± 8.43 vs. 11.55 ± 5.65 ng/mL, P < 0.001). The overall prevalence of PAD was 7.7%. From the highest level (≥ 20 ng/mL) to the lowest level (< 10 ng/mL) of serum 25(OH)D, the prevalence of PAD was 2.8, 7.5 and 10.7% respectively. After adjustment for age, sex, body mass index (BMI), smoking status and season, compared to patients with serum 25(OH)D levels ≥20 ng/mL, the odds ratios of PAD in patients with a level of 10 to < 20 ng/mL and < 10 ng/mL was 3.587(95% CI: 1.314-9.790) and 5.540(95% CI: 2.004-15.320), respectively. When further considering the influence of coronary heart disease (CHD), hypertension and cerebral infarction, the ratios changed to 3.824(95% CI: 1.378-10.615) and 5.729(95% CI: 2.028-16.187), respectively. And after further adjustment for the duration of diabetes, glycated hemoglobin (HbA1c) and glomerular filtration rate (GFR), the ratios changed to 3.489(95% CI: 1.100-11.062) and 3.872(95% CI: 1.168-12.841), respectively. CONCLUSIONS: Reduced serum vitamin D levels were associated with an increased risk of PAD in T2DM patients. Randomized interventive clinical studies are required to verify the effects of vitamin D supplementation on PAD.

Tongxinluo ameliorates renal structure and function by regulating miR-21-induced epithelial-to-mesenchymal transition in diabetic nephropathy.

Diabetic nephropathy (DN) is one of the most important diabetic microangiopathies. The epithelial-to-mesenchymal transition (EMT) plays an important role in DN. The physiological role of microRNA-21 (miR-21) was closely linked to EMT. However, it remained elusive whether tongxinluo (TXL) ameliorated renal structure and function by regulating miR-21-induced EMT in DN. This study aimed to determine the effect of TXL on miR-21-induced renal tubular EMT and to explore the relationship between miR-21 and TGF-ß1/smads signals. Real-time RT-PCR, cell transfection, in situ hybridization (ISH), and laser confocal microscopy were used, respectively. Here, we revealed that TXL dose dependently lowered miR-21 expression in tissue, serum, and cells. Overexpression of miR-21 can enhance α-smooth muscle actin (SMA) expression and decrease E-cadherin expression by upregulating smad3/p-smad3 expression and downregulating smad7 expression. Interestingly, TXL also increased E-cadherin expression and decreased α-SMA expression by regulating miR-21 expression. More importantly, TXL decreased collagen IV, fibronectin, glomerular basement membrane, glomerular area, and the albumin/creatinine ratio, whereas it increased the creatinine clearance ratio. The results demonstrated that TXL ameliorated renal structure and function by regulating miR-21-induced EMT, which was one of the mechanisms to protect against DN, and that miR-21 may be one of the therapeutic targets for TXL in DN.