Effect of Vitamin D Status on Vascular Function of the Aorta in a Rat Model of PCOS

Polycystic ovary syndrome (PCOS) is associated with elevated cardiovascular risk. Early vascular dysfunction may lead to the development of cardiovascular disease in PCOS. Vitamin D deficiency (VDD) is a common comorbidity of PCOS that contributes to the pathogenesis of the disease and its complications. Both PCOS and VDD are accompanied by increased oxidative stress that may be involved in the arising vascular dysfunction. We aimed to investigate the role of vitamin D status on aortic function. PCOS was induced by an 8-week-long transdermal testosterone treatment of female rats, and low and adequate vitamin D status was achieved by dietary means. Contraction and relaxation abilities of isolated aortic segments were measured by myograph. Resorcin-fuchsin staining and immunohistochemical labeling of 3-nitrotyrosine were performed. No difference was shown in the norepinephrine-induced contraction of the aortas of different groups, whereas we detected reduced acetylcholine- and insulin-evoked relaxation in VDD groups. A lower level of resorcin-fuchsin staining and elevated 3-nitrotyrosine immunostaining was observed in VDD. In our study, we demonstrated early endothelial dysfunction in VDD PCOS rat model. Vitamin D supplementation could prevent vascular disturbances, while VDD itself damaged endothelium-dependent vasorelaxation and induced nitrative stress.

Evaluation of oxidative/nitrative stress and uterine artery pulsatility index in early pregnancy

Introduction

Increased oxidative/nitrative stress is characteristic not only in pathologic, but also in healthy pregnancy. High uterine artery pulsatility index (UtAPI) at the end of the first trimester is associated with altered placentation and elevated risk for adverse pregnancy outcomes. We aimed to examine the relationship of systemic oxidative/nitrative stress and uterine artery pulsatility index in the first trimester and their correlation to pregnancy outcomes.

Material and methods

Healthy pregnant women were recruited at 12-13th gestational week ultrasound examination; UtAPI was determined by color Doppler ultrasound. Patients were divided into high (UtAPI ≥ 2.3) (n = 30) and low (n = 31) resistance groups, and pregnancies were followed until labor. Systemic oxidative/nitrative stress was estimated by measuring total peroxide level, total antioxidant capacity and nitrotyrosine level.

Results

Plasma total peroxide level was significantly lower (2,510 ± 39 µM vs. 2,285 ± 59 µM), total antioxidant capacity was higher (781 ± 16 mM CRE vs. 822 ± 13 mM CRE) in the high UtAPI group, which were accompanied by lower birth weight (3,317 ± 64 vs. 3,517 ± 77 g, P < 0.05). Plasma total peroxide level showed a negative correlation (by Pearson) to UtAPI (P < 0.01) and positive correlation to birth weight (P < 0.05).

Conclusions

According to our results, lower systemic oxidative stress showed correlation with high UtAPI measured between the 12-13th weeks of gestation. We also found significant differences in the birth weight of healthy newborns; therefore it is worth examining this relationship in pathological pregnancies.

Effect of parathyroid extract and of glutaurine (gamma-L-glutamyl-taurine) on the manifestations of osteolathyrism

BAPN-induced osteolathyrism in young and older male rats was examined for its responses to parathormone-free, gel-filtered bovine parathyroid extract (extract P) and to glutaurine (gamma-L-glutamyl-taurine), the latter being a hitherto unknown putative hormone isolated from bovine parathyroid and reproduced by synthesis. In case of the daily administration of 20 mg BAPN + 0.2 mg extract P/100 g body weight and of 40 mg BAPN + 0.2 micrograms glutaurine/100 g body weight, both substances were found to attenuate the manifestations of osteolathyrism, to a significant extent, without, however preventing their development completely. The significantly decreased Ca, P, chondroitine sulphate and chrondroprotein values due to the administration of BAPN showed a significant, or highly significant, increase for the cartilage in response to extract P, and for both cartilage and bone in response to glutaurine, without however, attaining the control values. Additional evidence has been furnished by the present study that synthetic glutaurine is equal to the parathormone-free, gel-filtered parathyroid extract (extract P) in its attenuating effect on experimental osteolathyrism.

Protein-corticosteroid interactions in peripheral plasma and synovial fluid of patients with rheumatoid arthritis and osteoarthrosis

The individual protein fractions, together with the unbound (biologically active) and specifically globulin-bound 11-hydroxysteroids, were determined in the plasma and synovial fluid of patients with rheumatoid arthritis (RA). The values were compared with those measured in control subjects and in patients with severe osteoarthrosis (OA). Hypoalabuminaemia and hyperglobulinaemia, as well as an increase in the unbound and a decrease in the specifically bound corticosteroids were found in the plasma of the RA patients. The protein and corticosteroid levels were lower, and the level of the protein-bound corticosteroid fraction higher, in the synovial fluid than in the plasma. Significant differences between the RA and OA patients in respect of these parameters were also observed. The findings indicate that the altered hormone pattern is not a nonspecific result of the permanent stress situation to which RA patients are subjected. They point out the existence of a fairly specific but still unknown mechanism that compensates the high level of unbound corticosteroids, thus accounting for the absence of any clinical signs of hypercortisonism.

Influence of protein free aqueous extract of parathyroid powder on serum vitamin A level in rats

Administration of the protein-free extract of bovine parathyroid powder to rats resulted in a significant increase of the serum vitamin A level.