Transdermal estradiol reduces F2alpha-isoprostane levels in postmenopausal women

Potential efficiency of antioxidants to prevent pressure ulcers. A neglected hypothesis

Pressure ulcers are necrotic lesions mainly due to capillary hypoperfusion. It is well known that hypoxia and also subsequent oxygenation at reperfusion provoke the formation of reactive oxygen species (ROS) responsible for cell death. The hypothesis of their participation in the pathogenesis of pressure ulcers has already been tested; several antioxidants have the capacity to inhibit skin necrosis in animal models but their efficiency in preventing bedsores has never been demonstrated in patients. The failure of clinical trials to show the protective activity of some antioxidants does not rule out the involvement of ROS in ischemic ulcers and the potential efficacy of other antioxidants in preventing their formation remains possible.

Fatty acids as determinants of in-vivo lipid peroxidation: the EFFGE study in Eastern Finnish hypertensive and non-hypertensive subjects

BACKGROUND

The degree of fatty acid (FA) unsaturation as a determinant of lipid peroxidation has been inadequately studied.

METHODS

We examined associations of plasma free F2α-isoprostanes (F2-IsoPs), an indicator of in-vivo lipid peroxidation, with the levels/intake of FAs, adjusted for the risk factors of cardiovascular disease (CVD) in 1211 Finnish men and women, of whom 50% were hypertensive, aged 59.3 ± 8.3 years, mean ± SD.

RESULTS

Elevated age- and sex-adjusted plasma free levels of omega-6 and omega-3 polyunsaturated Fas (PUFAs), saturated FAs (SFAs), and the PUFA/SFA and the omega-6/omega-3 PUFA ratios were all associated with decreased F2-IsoPs. High dietary SFA intake was associated with elevated F2-IsoP concentrations. In a multivariable regression (with clinical, nutritional, and behavioral CVD risk factors), female gender, body mass index (BMI), serum apolipoprotein A1, and NT-proBNP (natriuretic peptide) were positively associated with the F2-IsoPs, whereas the dietary PUFA/SFA ratio, plasma β-carotene, the omega-6/omega-3 PUFA ratio, and protein intake showed inverse associations.

CONCLUSIONS

We propose that elevated lipid peroxidation is associated with several risk factors of CVD, such as a low PUFA/SFA ratio, whereas the FA precursors of lipid peroxidation, i.e. omega-3 and omega-6 PUFAs are associated with attenuated F2-IsoP levels. These findings provide mechanistic support for earlier observations linking PUFA to improved cardiovascular health.

Impact of serum estradiol on postprandial lipemia, oxidative stress, and inflammation across a single menstrual cycle

BACKGROUND

An abrupt rise in circulating lipids, oxidative stress, and inflammatory biomarkers is a common finding after ingestion of a high-fat meal. Estradiol, typically provided via hormone replacement therapy to postmenopausal women, has been reported to possess lipidemic, antioxidant, and antiinflammatory properties, all of which may minimize postprandial oxidative stress.

OBJECTIVE

The purpose of this study was to compare the postprandial triglyceride (TG), oxidative stress, and inflammatory responses after a lipid meal in menstruating women during the early follicular (days 1-3) and preovulatory (day 14) phases of the menstrual cycle.

METHODS

Healthy normolipidemic women (fasting blood TG, <200 mg/dL) with regular menstrual cycles reported to the Cardiorespiratory/Metabolic Laboratory at the University of Memphis, Memphis, Tennessee (October-December 2008) and consumed an identical lipid meal (heavy whipping cream and water) on 2 separate days during the menstrual cycle. Blood samples were collected premeal and 1, 2, 4, and 6 hours postmeal, then assayed for TG, malondialdehyde (MDA), hydrogen peroxide, Trolox equivalent antioxidant capacity (TEAL), nitrate/nitrite, and C-reactive protein (CRP). The AUC was calculated for each variable, and a 2 (menstrual cycle phase) x 5 (time) ANOVA with Tukey post hoc testing was also conducted. Estradiol concentration was measured in premeal samples for verification of cycle phase.

RESULTS

Ten women (mean [SD] age, 29 [11] years; 8 white, 2 black; body mass index, 22 [3] kg/m(2)) participated in the study. Despite a higher serum estradiol concentration on day 14 (113 [56] pg/mL) compared with the early follicular phase (61 [34] pg/mL), the TG, oxidative stress, and inflammatory AUC responses to feeding were not significantly different. TG (P = 0.03), MDA (P = 0.02), and hydrogen peroxide (P < 0.001) were significantly increased in response to feeding (time effect), whereas nitrate/nitrite was decreased (P = 0.01). TEAC and CRP were not significantly affected.

CONCLUSIONS

These data indicate that estradiol, at the concentrations noted in the present study, had no significant effect on postprandial TG or biomarkers of oxidative stress or inflammation in a sample of young, healthy women. It is possible that a greater divergence in circulating estradiol may be needed for significant differences to be detected, as may be the case with chronic hormone replacement therapy in postmenopausal women.

Ischemia/reperfusion unveils impaired capacity of older adults to restrain oxidative insult

Age independently predicts poor outcome in a variety of medical settings, including sepsis, trauma, severe burns, and surgery. Because these conditions are associated with oxidative stress, we hypothesized that the capacity to constrain oxidative insult diminishes with age, leading to more extensive oxidative damage during trauma. To test this hypothesis, we used suprasystolic inflation of an arm blood pressure cuff to safely induce localized forearm ischemia/reperfusion (I/R) and quantified plasma F(2)-isoprostane (IsoP) levels in serial blood samples. Before I/R, IsoP levels were similar in young (20-33 years) and older adults (62-81 years). After I/R challenge, the magnitude and duration of increased IsoP levels was significantly greater in older adults. Because aging is associated with declining levels of sex hormones that contribute to the regulation of antioxidant enzyme expression, we then examined the response to I/R in older women receiving hormone replacement therapy and found that these women did not manifest the amplified IsoP response found in untreated older women. These findings demonstrate that aging impairs the ability to restrain oxidative damage after an acute insult, which may contribute to the increased vulnerability of older adults to traumatic conditions and establishes a useful method to identify effective interventions to ameliorate this deficiency.