Impaired microvascular reactivity in gestational diabetes is associated with altered glycemic parameters.

OBJECTIVES: To assess microvascular reactivity and glycemic parameters in GDM compared to age and GA matched controls. METHODS: This study involved 21 GDM patients and 31 controls. Microvascular reactivity was assessed using LDF and PORH. Microvascular parameters; PORHmax , PORHpeak , and time to peak perfusion (Tp) were recorded after the release of 3 minutes' upper arm occlusion. HOMA-IR was performed to evaluate insulin resistance. RESULTS: Average age and GA for subjects were 32.9 years and 29.2 weeks. Mean FBG and a 2-hour postprandial for GDM and controls were 4.87 ± 0.71 vs 3.99 ± 0.59 mmol/L; P < 0.001 and 9.50 ± 1.8 vs 5.67 ± 1.0 mmol/L; P < 0.001. Fasting insulin (13.88 ± 18.9 vs 8.37 ± 11.0 µLU/mL; P = 0.031) and HOMA-IR (3.14 ± 4.6 vs 1.52 ± 2.2; P = 0.004) were higher in GDM. Tp was prolonged in GDM (16.27 ± 4.3 vs 13.86 ± 2.1 seconds; P = 0.011). Positive correlations were seen between Tp and FBG and 2-hour postprandial levels. CONCLUSION: Tp was prolonged in GDM compared to age-matched controls, indicating impaired microvascular reactivity.

Vitamin D status and oxidative stress in diabetes mellitus.

Diabetes mellitus is an epidemic that is gaining global concern. Chronic hyperglycemia in diabetes induces the excess production of free radicals. The deleterious effects of excess free radicals are encountered by endogenous antioxidant defense system. Imbalance between free radicals production and antioxidants defense mechanisms leads to a condition known as "oxidative stress". Diabetes mellitus is associated with augmented oxidative stress that induced micro- and macrovascular complications, which presents a significant risk for cardiovascular events. Low vitamin D levels in the body have also been reported to be associated with the pathogenesis of diabetes and enhanced oxidative stress. The article is to review available literature and summarize the relationship between oxidative stress and vitamin D levels in diabetes. We also review the effects of vitamin D analogs supplementation in improving oxidative stress in diabetics.

Effects of 1α-Calcidol (Alfacalcidol) on Microvascular Endothelial Function, Arterial Stiffness, and Blood Pressure in Type II Diabetic Nephropathy Patients.

OBJECTIVES: To determine the effects of six months alfacalcidol on microvascular endothelial function, arterial stiffness, and BP in DN patients. METHODS: Twenty-eight DN patients on alfacalcidol, 0.25 µg daily for six months were compared to 32 controls on conventional treatment. Measurements of microvascular endothelial function, arterial stiffness [AIx and PWV], hsCRP, and BP were performed; differences between baseline and six months treatment were evaluated. RESULTS: No difference was seen in microvascular endothelial function for both groups after six months. Improvement in CSBP (p = 0.027) with trends of improvement in AIx (p = 0.063), PWV (p = 0.075), and systolic BP (p = 0.088) were seen in the alfacalcidol group with no changes observed in controls. Subgroup analysis of alfacalcidol group showed that vitamin D-deficient patients had better response to treatment. hsCRP level remained unchanged in alfacalcidol group; significant increase was however seen in controls. CONCLUSION: Alfacalcidol did not have an effect on microvascular endothelial function in DN patients. Alfacalcidol significantly improved CSBP with trends of improvement in arterial stiffness and peripheral BP. Alfacalcidol appears to be more beneficial in vitamin D-deficient patients.