Magdalena Kujawska-Łuczak

Effects of green tea supplementation on inflammation markers, antioxidant status and blood pressure in NaCl-induced hypertensive rat model

ABSTRACT Background: Recent studies indicate the important role of chronic inflammation and oxidative stress in the pathogenesis of hypertension. Green tea, due to the high content of catechins, shows high antioxidant activity. Objective: To determine the effect of supplementation with green tea extract on the blood pressure, on the concentration of selected parameters of inflammation and antioxidant status in the model of high-sodium-diet induced hypertension. Design: The study lasted 42 days. The experimental population consisted of 30 rats. The rats were divided into three groups. The rats in the control group were fed a standard diet with 35 g of NaCl per kg of diet, in the second group hypertensive rats were fed a standard diet with NaCl (35 g/kg diet) and with an extract of green tea (2 g/kg diet). The third group consisted of hypertensive rats fed a standard diet with NaCl (35 g/kg diet), and 4 g of green tea extract/kg diet. Results: Supplementation with green tea had no effect on body mass of rats on a high-sodium diet. At the end of the experiment systolic blood pressures in SH2 and SH4 groups were significantly lower than in the control group SK. The SH4 group was characterized by a significantly lower diastolic blood pressure value and concentration of TNF-α in comparison to the SK group. The rats from both SH2 and SH4 groups were characterized by higher total antioxidant status values compared to the control group. Discussion: The mechanism of the beneficial effects of green tea on blood pressure is not clear, but it is believed that it is related to its omnidirectional properties. Conclusions: Supplementation of green tea has a beneficial effect on blood pressure, markers of inflammation and antioxidant status in an experimental model of hypertension.

The effect of orlistat versus metformin on body composition and insulin resistance in obese premenopausal women: 3-month randomized prospective open-label study

Introduction Our aim was to evaluate the effects of metformin and orlistat on body composition and glucose–insulin homeostasis in obese premenopausal women. Material and methods Seventy-three obese premenopausal Caucasian women aged 32.4 ±8.3 years were treated with either metformin (1000 mg/day; n = 37) or orlistat (360 mg/day; n = 36). Anthropometric parameters were measured using dual-energy X-ray absorptiometry. Glucose tolerance, using the oral glucose tolerance test; insulin resistance, using the homeostasis model assessment (HOMA-IR); and insulin sensitivity, using the Matsuda insulin sensitivity index (ISI Matsuda), were assessed at the commencement of the study and after 3 months. Results Those treated with orlistat showed greater weight loss (−9.4 ±2.3 vs. –4.9 ±1.3 kg, p < 0.05) and decrease of fat mass (−5.4 ±3.0 vs. –3.5 ±0.7 kg, p < 0.05) than those treated with metformin. The percentage of android and gynoid fat deposits was reduced in both groups; however, a greater decrease in android fat was observed in those treated with metformin. Improvement in ISI Matsuda and post-load insulin were similar in both groups. High initial post-load insulin and low ISI Matsuda corresponded with reductions in total fat, trunk fat, and waist circumference in both groups, and a decrease in android fat in those treated with metformin. Conclusions Orlistat treatment resulted in greater weight loss and improvement in body composition; metformin treatment resulted in a reduction of android fat. Both drugs produced a comparable improvement in insulin/glucose homeostasis. Overall, insulin-resistant women showed improvement with treatment, irrespective of which drug was used.

The effect of L-arginine and ascorbic acid on the visceral fat and the concentrations of metalloproteinases 2 and 9 in high-fat-diet rats

INTRODUCTION L-arginine (L-arg) and vitamin C supplementation may decrease fat accumulation and have a favourable effect on carbohydrate metabolism. This is partly caused by matrix metalloproteinases (MMPs), which are involved in adipocyte development and remodelling. Our study evaluated the effects of L-arg and vitamin C supplementation on the content of visceral fat (VF%), activity of MMPs, and insulin resistance (IR) in rats fed a high-fat diet (HFD). MATERIAL AND METHODS The experiment was performed using 48 Wistar rats divided into four groups: Group 1 was fed a standard diet, Group 2 a HFD, Group 3 a HFD supplemented with L-arg (A), and Group 4 a HFD supplemented with L-arg and vitamin C (AC). The animals were euthanized after six weeks. The concentrations of serum glucose, insulin, MMP-2, and MMP-9, as well as IR by Homeostatic Model Assessment (HOMA) and VF% were measured. RESULTS Statistically significant increases in VF%, MMP-2, MMP-9, insulin, and HOMA-IR levels were observed in the HFD group when compared to the control group. A smaller increase in VF%, insulin, and HOMA-IR was seen in Group 3 (A) and 4 (AC). L-arg supplementation protected against increases in MMP-2 and MMP-9 in Group 3 (A) and 4 (AC). CONCLUSIONS L-arginine could protect from an increase in visceral fat through a change in the activity of MMPs and amelioration of insulin sensitivity in rats fed a HFD. The addition of vitamin C did not improve the effects of L-arginine supplementation.