Stefania Ferrazzini

Oxidative Stress and Bone Resorption Interplay as a Possible Trigger for Postmenopausal Osteoporosis

The underlying mechanism in postmenopausal osteoporosis (PO) is an imbalance between bone resorption and formation. This study was conducted to investigate whether oxidative stress (OxS) might have a role in this derangement of bone homeostasis. In a sample of 167 postmenopausal women, we found that increased serum levels of a lipid peroxidation marker, hydroperoxides, were negatively and independently associated with decreased bone mineral density (BMD) in total body (r = −0.192, P < 0.05), lumbar spine (r = −0.282, P < 0.01), and total hip (r = −0.282, P < 0.05), as well as with increased bone resorption rate (r = 0.233, P < 0.05), as assessed by the serum concentration of C-terminal telopeptide of type I collagen (CTX-1). On the contrary, the OxS marker failed to be correlated with the serum levels of bone-specific alkaline phosphatase (BAP), that is, elective marker of bone formation. Importantly, multiple regression analysis revealed that hydroperoxides is a determinant factor for the statistical association between lumbar spine BMD and CTX-1 levels. Taken together, our data suggest that OxS might mediate, by enhancing bone resorption, the uncoupling of bone turnover that underlies PO development.

17β-estradiol levels and oxidative balance in a population of pre-, peri-, and post-menopausal women

Background. The high incidence of various diseases observed in post-menopausal women has been widely associated to the decline of 17β-estradiol (E2) occurring in correspondence of menopausal transition. One of the mechanisms suggested to explain this link takes into account the ability of E2 to counteract oxidative stress (OS) which is believed to play an important role in several pathogenic processes. Aim. To investigate whether stages of womens life characterized by different levels of E2 influence OS. Subjects and methods. We conducted a cross sectional study of OS markers in 159 women subdivided in 65 pre-menopausal, 36 peri-menopausal, and 58 post-menopausal classified according to the Staging of Reproductive Aging Workshop (STRAW) criteria. E2, follicle-stimulating hormone, and markers of OS including hydroperoxides, thiols, uric acid, total and residual antioxidant power, were assessed. Results. After adjustment for covariates, only total antioxidant power was significantly different according to menopausal status (p <0.01), with lower value in pre- with respect peri- and post-menopausal women. No significant correlations between E2 levels and OS markers were detected. Conclusions. Endogen E2, and, consequently, its decline during menopausal transition, is not a determinant factor for OS.

Metabolic transitions at menopause: In post-menopausal women the increase in serum uric acid correlates with abdominal adiposity as assessed by DXA

OBJECTIVES The present study aimed to investigate any associations between parameters of body fat mass distribution and levels of serum uric acid (sUA), a well-documented cardiovascular risk factor, among non-obese women ranging from pre- to post-menopausal status. METHODS In this cross-sectional population-based study we assessed body fat distribution by dual-energy-X-ray absorptiometry (DXA), and sUA levels in 101 pre- and 134 post-menopausal non-obese apparently healthy women. RESULTS Multivariate stepwise regression analysis revealed that sUA was independently associated to the indicators of overall fatness, i.e. body mass index (β=0.339, p<0.001) and DXA-assessed total and percentage body fat (β=0.366, p<0.001 and β=0.412, p<0.001, respectively), only among post-menopausal women. Within this sample subset, trunk (i.e. central) fat mass emerged as a strong predictor of sUA (β=0.408, p<0.001), after taking the potential confounders (including body mass index) into account. CONCLUSION Central fat accumulation was found to be independently associated with higher sUA levels among non-obese women in post- but not among those in pre-menopause.

Waist circumference and dual-energy X-ray absorptiometry measures of overall and central obesity are similarly associated with systemic oxidative stress in women

Abstract Growing evidence suggests that overall and abdominal obesity might lead to oxidative stress (OxS), which, in turn, plays a key role in the pathogenesis of a wide spectrum of diseases. In this study, for the first time, we compared the correlations of indirect, i.e. anthropometric, and direct, by dual energy X-ray absorptiometry (DXA), measures of body fat with circulatory OxS markers in women. To address this issue, we assessed central and total body fat mass (FM) by DXA, and serum levels of advanced oxidation protein products (AOPP), thiols and hydroperoxides in 275 healthy women (age 21–65 years; body mass index [BMI] 21.1–32.0 kg/m2; waist circumference [WC] 60.1–109.9 cm). Among the markers considered in the study, only hydroperoxides levels, i.e. by-products of lipid peroxidation, were significantly (p < 0.05 for all) and positively correlated to body fat accumulation after controlling for confounding factors. In particular, this marker was found to be similarly associated with DXA-derived total FM, total FM % and trunk FM as well as with WC. Of note, hydroperoxides appeared to be correlated with abdominal but not with general obesity, as classified according to standard WC and BMI cut-offs, respectively. In conclusion, taken together our data demonstrated that, at least in women, the measurement of body FM by DXA has no advantage over the simpler and cheaper WC with regard to their associations with systemic OxS markers. Moreover, WC emerged as a superior potential predictor of OxS compared to the other most commonly used anthropometric measures (including BMI and waist to hip ratio).

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

Abstract The aim of the present study was to investigate whether accumulation of central fat is correlated with systemic oxidative stress (OxS) in non-obese apparently healthy postmenopausal women. Serum parameters of OxS (hydroperoxides and non-enzymatic antioxidants) along with body fat distribution, as assessed by dual-energy-X-ray absorptiometry (DXA), were evaluated in 134 non-obese postmenopausal women. Multiple regression analysis showed that central (trunk) fat significantly correlated with both markers of OxS independently of confounding factors (i.e. BMI, smoking, age, hypertension, legs and arms fat mass). In specific, the standardized regression coefficient was positive for hydroperoxides (β = 0.324, p < 0.05) and negative for antioxidants (β = −0.495, p < 0.01) level. In conclusion, the current data showed that the increase in central fat is an independent predictor of OxS condition among non-obese women in postmenopausal status. The possible pro-oxidant effects of the excess in central adiposity might be more harmful among post- than among pre-menopausal women, due to the postulated ability of E2 to contrast oxidative challenge and the related diseases.