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Little published information is available regarding epidemiological data on vitamin D status in the large geographical region of Central Europe (CE). We searched the journal literature with regard to 25(OH)D concentrations among community-dwelling or healthy people living in CE. 25(OH)D concentrations varied by age, season, study sample size, and methodological approach [i.e., 25(OH)D assay used]. Concentrations of 25(OH)D in CE appeared lower than 30 ng/mL, and the magnitude of hypovitaminosis D was similar to that reported in Western Europe. While most of the studies reviewed were cross-sectional studies, a longitudinal study was also included to obtain information on seasonal variability. The longitudinal study reported wintertime 25(OH)D values close to 21–23 ng/mL for all studied age groups, with a significant increase of 25(OH)D in August reaching 42 ng/mL for those aged 0–9 years, but only 21 ng/mL for the elderly aged 80–89 years. The decrease in 25(OH)D with respect to age was attributed to decreased time spent in the sun and decreased vitamin D production efficiency. Based on the literature review on vitamin D status in the CE populations, it can be concluded that 25(OH)vitamin D levels are on average below the 30 ng/mL level.

Objective To determine whether hormone replacement therapy can reverse established renal microvascular damage in type 2 diabetes and hypertension.Design Prospective, single centre clinical trial.Setting Outpatient clinics. ParticipantsMethods Administration of a cyclic combination of oestradiol and norgestrel orally for 3.5 monthly cycles. ResultsComparing the baseline values, mean (SD) 24-hour urine protein excretion was reduced from 0.452 g (0-039) to 0.370 g (0-047) (P c 0.01) and creatinine clearance was increased from 1-68 d s e c (0.11) to 1.77 d s e c (0-08) (P < 0.05). Fasting plasma glucose also improved from 6.92 mmoVL (0.47) to 6.51 mmoVL (0.28) ( P c 0.05), as did serum total cholesterol from 7.26 mmol/L (0.28) to 6.65 mmoVL (0.14) (P < 0.05). Blood pressure did not change significantly.Univariate linear regression analysis showed no significant correlation between the individual changes in blood pressure, fasting plasma glucose or serum cholesterol and the individual changes in proteinuria or creatinine clearance.Conclusions This study shows that hormone replacement therapy may reduce proteinuria, and even improve creatinine clearance, in diabetic and hypertensive postmenopausal women. These effects are additive to nephroprotective therapy, and the mechanisms appear unrelated to conventional risk factors for vascular complications, such as high blood pressure, elevated plasma glucose or serum cholesterol.Sixteen diabetic and hypertensive postmenopausal women (age 47-57 years)

Hyperandrogenic state in females is accompanied with metabolic syndrome, insulin resistance and vascular pathologies. A total of 67%-85% of hyperandrogenic women suffer also from vitamin D deficiency. We aimed to check a potential interplay between hyperandrogenism and vitamin D deficiency in producing insulin resistance and effects on coronary resistance arteries. Adolescent female rats were divided into four groups, 11-12 animals in each. Transdermal testosterone-treated and vehicle-treated animals were kept either on vitamin D-deficient or on vitamin D-supplemented diet for 8 weeks. Plasma sexual steroid, insulin, leptin and vitamin D plasma levels were measured, and oral glucose tolerance test was performed. In coronary arterioles, insulin receptor and vitamin D receptor expressions were tested by immunohistochemistry, and insulin-induced relaxation was measured in vitro on isolated coronary resistance artery segments. Testosterone impaired glucose tolerance, and it diminished insulin relaxation but did not affect the expression of insulin and vitamin D receptors in vascular tissue. Vitamin D deficiency elevated postprandial insulin levels and homeostatic model assessment insulin resistance. It also diminished insulin-induced coronary arteriole relaxation, while it raised the expression of vitamin D and insulin receptors in the endothelial and medial layers. Our conclusion is that both hyperandrogenism and vitamin D deficiency reduce sensitivity of coronary vascular tissue to insulin, but they do it with different mechanisms.

Objective: To investigate the vascular dysfunction caused by insulin resistance in polycystic ovary syndrome (PCOS) and the effectiveness of vitamin D in an animal model. Design: Controlled experimental animal study. Setting: Animal laboratory at a university research institute. Animal(s): Thirty female Wistar rats. Intervention(s): Rats were divided into groups at age 21-28 weeks. Twenty of them were subjected to dihydrotestosterone (DHT) treatment (83 mg/d); ten of them also received parallel vitamin D treatment (120 ng/100 g/wk). Oral glucose tolerance tests with insulin level measurements were performed. Gracilis arterioles were tested for their contractility as well as their nitric oxide (NO)-dependent and insulin-induced dilation using pressure arteriography. Main Outcome Measure(s): Several physiologic parameters, glucose metabolism, and pressure arteriography. Result(s): DHT treatment increased the passive diameter of resistance arterioles, lowered norepinephrine-induced contraction (30.1 AE 4.7% vs. 8.7 AE 3.6%) and reduced acetylcholine-induced (122.0 AE 2.9% vs. 48.0 AE 1.4%) and insulin-induced (at 30 mU/mL: 21.7 AE 5.3 vs. 9.8 AE 5.6%) dilation. Vitamin D treatment restored insulin relaxation and norepinephrine-induced contractility; in contrast, it failed to alter NO-dependent relaxation.

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Background and purposeVitamin D deficiency (VDD) is a global health problem, which can lead to several pathophysiological consequences including cardiovascular diseases. Its impact on the cerebrovascular system is not well understood. The goal of the present work was to examine the effects of VDD on the morphological, biomechanical and functional properties of cerebral arterioles.MethodsFour-week-old male Wistar rats (n = 11 per group) were either fed with vitamin D deficient diet or received conventional rat chow with per os vitamin D supplementation. Cardiovascular parameters and hormone levels (testosterone, androstenedione, progesterone and 25-hydroxyvitamin D) were measured during the study. After 8 weeks of treatment anterior cerebral artery segments were prepared and their morphological, biomechanical and functional properties were examined using pressure microangiometry. Resorcin-fuchsin and smooth muscle actin staining were used to detect elastic fiber density and smooth muscle cell counts in the vessel wall, respectively. Sections were immunostained for eNOS and COX-2 as well.ResultsVDD markedly increased the wall thickness, the wall-to-lumen ratio and the wall cross-sectional area of arterioles as well as the number of smooth muscle cells in the tunica media. As a consequence, tangential wall stress was significantly lower in the VDD group. In addition, VDD increased the myogenic as well as the uridine 5’-triphosphate-induced tone and impaired bradykinin-induced relaxation. Decreased eNOS and increased COX-2 expression were also observed in the endothelium of VDD animals.ConclusionsVDD causes inward hypertrophic remodeling due to vascular smooth muscle cell proliferation and enhances the vessel tone probably because of increased vasoconstrictor prostanoid levels in young adult rats. In addition, the decreased eNOS expression results in endothelial dysfunction. These morphological and functional alterations can potentially compromise the cerebral circulation and lead to cerebrovascular disorders in VDD.

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