We have evaluated the effects of the different components of hormone replacement therapy (HRT) on the production of free radicals in platelet membranes from menopausal women. The study included 12 women in menopause for at least 6 months to a maximum of 4 years. First, the effect was determined of progestin only during the administration of 20 mg/day medroxyprogesterone acetate for 5 days. The peroxide production level was measured on day 0 and day 5. The second set of experiments was carried out in the first month of cyclic HRT with transdermal estradiol 50 micrograms/day from day 1 to day 25 and medroxy-progesterone acetate from day 13 to day 25. In this experiment, the peroxide level was evaluated on days 0, 12 and 25. A significant reduction of peroxide level was observed after oral medroxyprogesterone acetate administration. During HRT, we observed a similar reduction in lipid oxidation at the peak of the estrogen effect, and a further decrease with the administration of medroxyprogesterone acetate. It is concluded that reduction of lipid peroxidation during HRT is not only due to estrogens, but also depends upon the combined action of sex steroids. This observation justifies not only the combined regimen (estrogens plus progestin) in HRT, but also the positive effects of progestins alone on patients who cannot use estrogens.

It has been recently hypothesized that in PIH a placental oxidant-antioxidant imbalance might cause the release of lipoperoxidation products into the circulation, with subsequent damage of endothelial cell membranes. In this hypothesis the endothelial cell and further increase in circulating lipoperoxide levels, which are by themselves able to induce smooth muscle constriction and increased pressor responsiveness to angiotensin II. In order to investigate this issue, we studied the basal content of lipid peroxides in terms of malondialdehyde (MDA) in the syncytiotrophoblast plasma membranes (SPM) from PIH women. Moreover, we investigated the susceptibility to peroxidation of SPM using an in vitro oxidative stress as a tool to verify the predisposition to the in vivo development of peroxidation products. The fatty acid composition of the membranes was also analyzed. Microvillus membrane lipoperoxide concentrations were significantly increased in PIH women (62.8 +/- 7.6 ng MDA/mg prot) compared with healthy pregnant subjects (37.6 +/- 4.8 ng MDA/mg prot; p < 0.01). The formation of TBARS under the action of phenylhydrazine was significantly greater in PIH women (90.3 +/- 7.4 mmol MDA/mol cholesterol) than in normal pregnant subjects (68.6 +/- 6.4 mmol MDA/mol cholesterol; p < 0.01). In PIH microvillus membrane we also observed a significant increase of the content of polyunsaturated arachidonic acid. The increased susceptibility to oxidative stress of SPMs from PIH women might be due either to reduced antioxidant systems or to an abnormality of the lipid composition of the membrane.(ABSTRACT TRUNCATED AT 250 WORDS)

We have shown a modification in platelet NO and peroxynitrite production and an increase in platelet indicators of oxidative stress in GDM women compared with healthy pregnant women which might be at the basis of a cellular dysfunction.

Osteoporosis represents a serious health problem worldwide associated with an increased risk of fractures and mortality. Nutrition should form part of bone disease prevention strategies, especially in the light of the population ageing and the diet effect on bone health. Thus the study aimed at verifying whether 1 year of oral supplementation with either extra virgin olive oil (VOO) enriched with vitamins D3, K1 and B6 (VitVOO) or VOO used as placebo (PlaVOO) is able to modify some bone turnover and oxidative stress markers. Bone mineral density (BMD) was assessed in 60 healthy post-menopausal women together with the bone vitamin K status by measuring undercarboxylated osteocalcine (ucOC) plasma levels, the ratio between ucOC and carboxylated osteocalcine (UCR) and the relations with oxidative stress markers. After 1 year (T 1), subjects taking VitVOO showed lower ucOC levels than those taking PlaVOO; the same trend was found for UCR. As far as BMD is concerned, a significant increase in T-score at T 1 in VitVOO subjects compared to PlaVOO was found. All oxidative stress markers as thiobarbituric acid reactive substances, lipid hydroperoxides and conjugated dienes showed a significant reduction after VitVOO supplementation, whilst plasma total antioxidant capacity values was significantly increased in VitVOO group compared to PlaVOO group at T 1. It might be suggested that the use of VitVOO in the diet of post-menopausal women could represent a proper tool for bone protection and a useful strategy against oxidative stress and related diseases, thus confirming the antioxidant role played by the added vitamins.

Plasma membrane lipid dynamics and cellular morphology were evaluated in endothelial cells obtained from umbilical cords of five women affected by insulin-dependent diabetes mellitus (IDDM) and six healthy pregnant women of similar age and gestational age. Endothelial cells were prepared by an adaptation of the method of Jaffe et al. Membrane fluidity was studied by means of the steady-state fluorescence anisotropy (r) of 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (TMA-DPH), a fluorescent probe specifically anchoring at the membrane surface. Fluid phase endocytosis was evaluated by the measurement of the changes in fluorescence intensity of TMA-DPH at various times, owing to the internalization of the fluorescent marker in endocytic vesicles. The morphological and morphometric studies were performed by means of transmission electron microscopy (TEM). Endothelial cells obtained from IDDM women showed: (a) increased fluidity of the superficial region of the plasma membrane; (b) a more active fluid phase endocytosis compared with cells from healthy women; (c) increase in mitochondrial area, Weibel-Palade bodies and rough reticulum with wide cisternae. No statistically significant correlation was found between metabolic control and membrane fluidity and endocytosis. All the observed modifications suggest the presence of endothelial cell activation with membrane reshaping during IDDM. These alterations might play a central role in the pathophysiology of atherosclerosis and microangiopathy associated with diabetes mellitus.