Impaired microvascular endothelial function in vitamin D-deficient diabetic nephropathy patients

Area of Science:

• Endocrinology
• Nephrology
• Vascular Biology

Background:

• Diabetic nephropathy is a common complication of diabetes mellitus, associated with microvascular damage.
• Vitamin D deficiency is prevalent in patients with chronic kidney disease, including diabetic nephropathy.
• Microvascular endothelial dysfunction contributes to the progression of diabetic nephropathy.

Purpose of the Study:

• To compare microvascular endothelial function in patients with diabetic nephropathy who are vitamin D-deficient versus those who are non-deficient.
• To investigate the association between vitamin D status and endothelial function in this patient population.

Main Methods:

• Prospective cross-sectional study of 70 patients with diabetic nephropathy.
• Patients were divided into vitamin D-deficient (<50 nmol/l) and non-deficient (>50 nmol/l) groups based on serum 25-hydroxyvitamin D levels.
• Microvascular endothelial function assessed using laser Doppler fluximetry and iontophoresis with acetylcholine and sodium nitroprusside.

Main Results:

• The vitamin D-deficient group exhibited significantly lower endothelium-dependent vasodilatation compared to the non-deficient group (P = 0.004).
• No significant differences were found in high-sensitivity C-reactive protein (hsCRP) levels, age, estimated glomerular filtration rate, blood pressure, or glycosylated hemoglobin between the groups.
• Mean serum 25(OH)D levels were 42.1 ± 1.3 nmol/l in the deficient group and 69.4 ± 2.9 nmol/l in the non-deficient group (P < 0.001).

Conclusions:

• Vitamin D deficiency is associated with significantly reduced microvascular endothelial function in patients with diabetic nephropathy.
• These findings highlight the potential role of vitamin D in preserving vascular health in diabetic nephropathy.