[Comparison of serum leptin and thyroid hormones levels in obese and non-obese women]

Many factors are known to be involved in a number of human pathologies of obesity including serum leptin and thyroid hormones levels. The purpose of this study was to compare the serum levels of leptin and thyroid hormones in obese and non-obese women, in Shiraz-Iran during 2006. In this case- control study, 35 women with BMI?30 Kg/m2 recruited as an obese group [Case group] and 35 women with healthy BMI [BMI<25 Kg/m2] were selected as a control group. General information data were gathered from each sample using questionnaires and face-to-face interviews. Body weight, height, waist and hip circumferences were measured and BMI, WHR and percent of body fat [%TBF] were calculated for each subject. Venous blood samples were drawn from subjects and serum was separated to determine the concentrations of serum leptin and thyroid hormones [T4, T3 and TSH] levels. Mean serum concentration of leptin was significantly higher in obese group than control group [p<0.001]. Serum leptin levels positively correlated to anthropometric indices [BMI, WHR,%TBF]. No significant difference was observed between obese and non-obese groups in serum thyroid hormones concentration. Serum leptin levels positively related to serum T3 levels [P<0.05]. This study indicated that obese women had higher leptin levels compared to non-obese. The interaction between thyroid hormone in particular T3 and leptin can be one of the reason for increasing the serum leptin level among obse women

Is obesity associated with increased plasma lipid peroxidation and oxidative stress in women?

The role of obesity in diabetes mellitus, hyperlipidemia, colon cancer, sudden death and other cardiovascular diseases has been confirmed by many studies. In this study, it was hypothesized that obesity is an independent risk factor for lipid peroxidation and decreased activity of cytoprotective enzymes in humans. To test the study hypothesis, we assessed lipid peroxidation by measuring the concentrations of plasma malondialdehyde [MDA] and the activity of erythrocyte copper-zinc superoxide dismutase [CuZn-SOD], glutathione peroxidase [GPX] and catalase [CAT] in 25 obese women [BMI=30-40 Kg/m2] and 25 women with healthy BMI [19-25Kg/m2]. The concentration of plasma MDA was significantly higher [P<0.001] in obese women [3.4 +/- 0.7 micro mol/L] compared to women with healthy BMI [1.4 +/- 0.3 micro mol/L]. Furthermore, there was a significantly positive correlation [r =0.75, P<0.0001] between BMI and plasma MDA. On the other hand, women with healthy BMI had significantly higher [P<0.001] erythrocyte CuZn-SOD [873 +/- 52 U/g Hb] and GPX [64.7 +/- 14.2 U/g Hb] activity than obese women [660 +/- 39 U/g Hb] and [48.5 +/- 13.1 U/g Hb], respectively. Furthermore, erythrocyte CuZn-SOD and GPX activity were negatively correlated with BMI [r =-0.52, P<0.0001 and r =-0.42, P<0.001], respectively. No significant difference was observed between two groups in erythrocyte CAT activity. We conclude that obesity, diabetes, renal or liver disease can decrease the activity of protective antioxidants and can enhance the systemic oxidative stress even in the absence of smoking

Assessment of oxidative stress markers related to atherosclerosis in pre-hypertensive women

Lipid peroxidation is a free radical-generating process which occurs on every membranous structure of the cell. Free radicals are known to be involved in a number of human pathologies including atherosclerosis. The purpose of this cross-sectional study was to examine the association between pre-hypertension status and oxidative stress markers [total antioxidant capacity [TAC] and malonedialdehyde [MDA] levels] in a random sample of cardiovascular disease-free women. In this study, 160 women of 20-45 years of age were randomly selected.General information data were gathered from each sample using questionnaires and face-to-face interviews. Blood pressure [BP] was measured for each subject. Body weight, height, and waist and hip circumferences were measured and body mass index [BMI] and waist-to-hip ratio [WHR] were calculated for each subject. Venous blood samples were drawn from the subjects, and plasma was separated. In this study, the oxidative stress status was assessed by measuring the concentrations of plasma MDA and TAC levels. Our results show that both systolic and diastolic blood pressures were inversely correlated with TAC [p<0.01] and positively correlated with MDA levels [p<0.01]. Particularly, compared to the normotensive subjects, the pre-hypertensives had19% lower TAC [p<0.05] and 22% higher MDA levels [p<0.01], after correcting for multiple comparisons and adjusting for age, body mass index, waist-to-hip ratio, and other potential confounders. Our findings revealed an association between pre-hypertension and oxidative stress markers linked to atherosclerosis process. Thus, the identification of the underlying molecular mechanisms in pre-hypertension, which seem to include oxidative stress, may serve as an important lead for developing potentially new treatment modalities in this group of patients at risk for future cardiovascular complications

Plasma iron is associated with lipid peroxidation in women

It has been suggested that the risk of coronary heart disease increases with increase of body iron stores. Free iron catalyzes the generation of free radicals and free radicals promote the oxidation of lipids. The aim of this cross-sectional study was to examine the association of plasma iron and factors that could affect its levels [antioxidant enzymes], with the concentration of plasma malondialdehyde [MDA] as a marker of lipid peroxidation. In this study, 160 women aged 20-45 years were randomly selected. A medical history was obtained for each subject prior to enrolment. We assessed lipid peroxidation and the activity of antioxidant enzymes by measuring the concentration of plasma MDA and the activities of erythrocyte copper zinc superoxide dismutase [CuZn-SOD] and glutathione peroxidase [GPX]. Our results show that those in the highest tertile of plasma iron were at least twice as likely to have higher plasma MDA levels. Among the factors affecting plasma iron levels, we found that the upper tertile of erythrocyte CuZn-SOD was inversely associated with higher plasma iron. No associations were found between the highest TIBC and MDA levels. There was no significant association between GPX and plasma iron. These findings support the concept that iron, as an important transition metal, might contribute to atherogenesis, along with the classic risk factors. A longitudinal study should confirm whether or not these MDA levels are connected to vascular disease and mortality