Accumulation of central fat correlates with an adverse oxidative balance in non-obese postmenopausal women

Oxidative Stress in Postmenopausal Women with or without Obesity

Oxidative stress, a key mediator of cardiovascular disease, metabolic alterations, and cancer, is independently associated with menopause and obesity. Yet, among postmenopausal women, the correlation between obesity and oxidative stress is poorly examined. Thus, in this study, we compared oxidative stress states in postmenopausal women with or without obesity. Body composition was assessed via DXA, while lipid peroxidation and total hydroperoxides were measured in patient's serum samples via thiobarbituric-acid-reactive substances (TBARS) and derivate-reactive oxygen metabolites (d-ROMs) assays, respectively. Accordingly, 31 postmenopausal women were enrolled: 12 with obesity and 19 of normal weight (mean (SD) age 71.0 (5.7) years). Doubled levels of serum markers of oxidative stress were observed in women with obesity in women with obesity compared to those of normal weight (H₂O₂: 32.35 (7.3) vs. 18.80 (3.4) mg H₂O₂/dL; malondialdehyde (MDA): 429.6 (138.1) vs. 155.9 (82.4) mM in women with or without obesity, respectively; p < 0.0001 for both). Correlation analysis showed that both markers of oxidative stress increased with an increasing body mass index (BMI), visceral fat mass, and trunk fat percentage, but not with fasting glucose levels. In conclusion, obesity and visceral fat are associated with a greater increase in oxidative stress in postmenopausal women, possibly increasing cardiometabolic and cancer risks.

[Relationship between central obesity and oxidative stress in premenopausal versus postmenopausal women]

Introduction

Background: endocrine changes in midlife women produce an increase in central obesity and oxidative stress, thus it is possible that obese postmenopausal women exhibit a higher oxidative stress than premenopausal women. Objective: to evaluate the relationship between central obesity and oxidative stress in premenopausal compared with postmenopausal women using different indices. Methods: this is a cross-sectional study that included 237 pre- and 255 post-menopausal women (40-60 years old). As oxidative stress markers we measured plasma malondialdehyde and serum uric acid levels, erythrocyte superoxide dismutase (SOD) and glutathione peroxidase (GPx), and total plasma antioxidant status. We also measured height, weight, and waist and hip circumferences, and we calculated body mass index (BMI), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR). Results: we found over 30% of women within the obesity range, whereas 50% were placed in the overweight category in both groups. Plasma malondialdehyde and serum uric acid levels were higher in women with overweight or obesity than in women with normal weight regardless of menopausal status. We found a positive correlation between WHtR and malondialdehyde level (r = 0.298, p < 0.0001) and serum uric acid level (r = 0.263, p < 0.0001), and a negative correlation with erythrocyte GPx activity (r = -0.148, p < 0.01). If we use a WHtR > 0.6, malondialdehyde and uric acid levels increase regardless of menopausal status. The other indices measured did not show any relationship. Conclusion: our findings suggest that there is an association between central obesity, as measured with WHtR, and increased oxidative stress regardless of menopausal status.

Oxidative damage and the pathogenesis of menopause related disturbances and diseases

The postmenopausal phase of life is frequently associated in women with subjective symptoms (e.g. vasomotor) and real diseases (atherosclerosis with coronary ischemia, osteoporosis, Alzheimer-type neurodegeneration, urogenital dystrophy), which together determine the post-menopausal syndrome. Observations that oxidative damage by reactive oxygen/nitrogen species in experimental models can contribute to the pathogenesis of these disturbances stimulated research on the relationships between menopause, its endocrine deficiency, oxidative balance and the "wellness" in postmenopausal life. The connection among these events is probably due to the loss of protective actions exerted by estrogens during the fertile life. Most recent studies have revealed that estrogens exert an antioxidant action not by direct chemical neutralization of reactants as it was expected until recently but by modulating the expression of antioxidant enzymes that control levels of biological reducing agents. Also nutritional antioxidants apparently act by a similar mechanism. From this perspective it is conceivable that a cumulative control of body oxidant challenges and biological defenses could help in monitoring between "normal" and "pathological" menopause. However, as clinical studies failed to confirm this scenario in vivo, we have decided to review the existing literature to understand the causes of this discrepancy and whether this was due to methodologic reasons or to real failure of the basic hypothesis.

Lipids generated during acute pancreatitis increase inflammatory status of macrophages by interfering with their M2 polarization

BACKGROUND

Necrosis of adipose tissue is a common complication of acute pancreatitis. The areas of steatonecrosis become a source of inflammatory mediators, including chemically modified fatty acids which could influence the progression of the systemic inflammation. In an experimental model of acute pancreatitis we analyzed the effects of lipids generated by two representative areas of adipose tissue on the switch to the M1 phenotype in macrophages.

METHODS

Pancreatitis was induced in rats by intraductal administration of 5% taurocholate and after 6 h, lipids from retroperitoneal, mesenteric or epididymal adipose tissues were collected. Lipid uptake, phenotype polarization and the activation of PPARγ and NFκB were evaluated in macrophages treated with these lipids.

RESULTS

After induction of pancreatitis, lipids from visceral adipose tissue promote the switch to an increased pro-inflammatory phenotype in macrophages. This effect is not related with a higher activation of NFκB but with an interfering effect on the activation of M2 phenotype.

CONCLUSIONS

During acute pancreatitis, lipids generated by some areas of adipose tissue interfere on the M2 polarization of macrophages, thus resulting in a more intense pro-inflammatory M1 response.

Association of serum tumor necrosis factor-related apoptosis inducing ligand with body fat distribution as assessed by dual X-rays absorptiometry

A low chronic inflammation mediated by cytokine release is considered a major pathogenic mechanism accounting for the higher risk of cardiovascular disease in the overweight/obese population. In this context, although the existence of a possible interaction between soluble tumor necrosis factor- (TNF-) related apoptosis inducing ligand (TRAIL) and quantity and localization, of adiposity in the body has been hypothesized, no studies have yet investigated this link by radiologic techniques able to assess directly fat mass (FM) in different body regions. To address this issue, we assessed body fat distribution by dual X-rays absorptiometry (DXA) in a sample of 103 women and investigated the possible association between the derived adiposity measures and serum TRAIL concentration. The level of TRAIL showed a positive and independent correlation with arms FM (P < 0.05), trunk FM (P < 0.001) and trunk FM% (P < 0.05), total FM and total FM% (P < 0.001 for both), and an inverse association with legs FM% (P < 0.05). Only trunk FM retained a significant correlation (P < 0.05) with TRAIL after adjusting for all the other indices of regional adiposity. In conclusion, from our study it emerged a significant and independent association of serum TRAIL levels with overall, and, mainly, central adiposity. Further studies are needed to longitudinally investigate the cause-effect relationship between change in body fat distribution and TRAIL.