Lucyna Kozlowska

Leptin, Thyrotropin, and Thyroid Hormones in Obese/Overweight Women Before and After Two Levels of Energy Deficit

The aim of our study was to compare serum concentration of leptin and pituitary-thyroid axis hormones in obese/overweight women before and after two levels of energy deficit with those parameters in lean women on adequate energy intake. Additionally, we attempted to elucidate if the effect of weight reduction could be related to anthropometric and hormonal parameters before treatment. Anthropometric and hormonal parameters—serum leptin, TSH, T4, fT4, T3 and leptin to fat mass (Lep/fm), T3/T4, fT4/T4, T4/TSH, fT4/TSH—were compared in two groups of women (n=18 each)—lean women (C: BMI 22.0±1.2) and overweight/obese (Ov/Ob: BMI 29.9±3.3). Ov/Ob women were subjected to weight-reducing treatment consisting of energy intake equal to 80% of calculated total energy expenditure for the first 4 wk and to 50% for subsequent 4 wk. All baseline hormone concentrations, Lep/fm, and fT4/T4 were higher in overweight/obese group. After 20% energy deficit decrease in BMI, percent body fat (fm%), leptin, T3, and TSH serum concentrations as well as in Lep/fm and T3/T4 was observed; T4/TSH increased, fT4, fT4/T4 and fT4/TSH did not change significantly. Increase in energy deficit from 20% to 50% resulted in normalization of Lep/fm, on the other hand, it provoked greater decline in thyroid hormone plasma concentration, which could hinder further mass reduction. Leptin and TSH levels were positively correlated after 50% energy deficit treatment. Changes in fm% were directly related to baseline T4/TSH, fT4/TSH, and log TSH. In conclusion, TSH serum concentration and its ratio to T4 and fT4 before weight reduction could be a good predictor of successful weight loss.

Influence of low protein diet on nonthyroidal illness syndrome in chronic renal failure.

Renal failure causes alterations in thyroid hormone metabolism known as nonthyroidal illness syndrome. In the present study we have examined the effect of a low protein diet (LPD) on circulating levels of hormones of the pituitary-thyroid axis, and tumor necrosis factor alpha (TNF-alpha) in patients with chronic renal failure. Seventeen subjects with conservatively treated chronic renal failure (estimated creatinine clearance 39.5±11.1 mL/min) were studied before and after 8 wk of dietary intervention (0.6 g/kg of ideal body mass protein, 30% of calories derived from fat, 62% of calories derived from carbohydrates, and 10 mg/kg of phosphorus). Body fat and fat-free mass remained unchanged. Urea and TNF-alpha serum concentrations significantly decreased, whereas T3 and total and free T4 serum concentrations increased significantly. Triiodothyronine level after treatment correlated negatively with baseline urea level. Changes in T3, T4, and fT4 serum concentrations as well as calculated peripheral deiodinase activity correlated negatively with their baseline values. Alterations in TNF-alpha correlated positively with protein intake, whereas changes in T4 and T4/TSH were inversely related to vegetal protein intake. In conclusion, low protein, low phosphorus diet, which is often prescribed to patients with moderate impairment of renal function, exerts a beneficial effect on low T3 syndrome coexisting with renal failure. The effect of low protein diet on the pituitary-thyroid axis is dependent on the degree of renal functional impairment and LPD-induced decrease in TNF-alpha may also contribute to the observed effects of dietary treatment.

Low protein diet causes a decrease in serum concentrations of leptin and tumour necrosis factor-alpha in patients with conservatively treated chronic renal failure.

Background:  Chronic renal failure (CRF) provokes derangement in various hormonal regulations of food intake and energy expenditure. In the present study, we have examined the effect of a low protein, low phosphorus diet on circulating levels of leptin, tumour necrosis factor (TNF)‐alpha, and insulin in patients with CRF.

Adiponectin, resistin and leptin response to dietary intervention in diabetic nephropathy.

OBJECTIVE Adipokines play an important role in metabolic regulations. Obesity, diabetes, and renal disturbances affect adipokine profile by influencing their complex effects on metabolism. Our objective was to assess the effect of low-energy diet intervention on serum adiponectin, leptin, and resistin levels in diabetic nephropathy. METHODS Seventeen subjects with diabetes type 2 and nephropathy participated in the study. After estimation of individual resting metabolic rates by indirect calorimetry, diets introducing 20% energy deficit were applied. At baseline and after 2 months of dieting, the following parameters were measured: body composition by dual x-ray spectrometry and serum adiponectin (Adp), leptin (Lep), resistin (Res), insulin, urea, creatinine, glucose, glycosylated hemoglobin, C-reactive protein, and tumor necrosis factor-alpha concentrations. Homeostatic model assessment (HOMA) was used to quantify insulin resistance. RESULTS Total energy, protein, and fat intakes diminished significantly with intentional dieting. Significant decreases in total body fat mass (FM) and its percentage in body mass (FM%) and trunk and gynoid fat mass, as well as in serum resistin and tumor necrosis factor-alpha levels, were also observed. Responses of adipokines to dietary treatment varied individually. Generally, they were affected by FM. Alterations in Lep concentrations correlated negatively with baseline FM, FM%, and android and gynoid fat mass and positively with changes in intake of protein, carbohydrates, and total energy of the consumed diet. Changes in Adp were inversely related to FM after therapy. Alterations in Res concentrations correlated positively with android fat mass before therapy and initial Lep levels. Adiponectin was inversely related to HOMA index before and after treatment. CONCLUSIONS Low-energy diet applied in diabetic nephropathy may decrease serum resistin levels and inflammation. In addition, responses of all adipokines to dieting appear to be affected by body fat mass, especially android fat mass.

Biomarkers of selenium status and antioxidant effect in workers occupationally exposed to mercury

The present observation based research was designed to evaluate the influence of occupational human exposure to metallic mercury (Hg°) vapor on the biomarkers of selenium status involved in the antioxidant defense system. For this purpose we determined Hg and selenium (Se) concentrations in body fluids, the markers of antioxidant effect measured as an activity of Se-dependent enzymes (red blood cell and plasma glutathione peroxidase: GPx1-RBC and GPx3-P), concentration of selenoprotein P in the plasma (SeP-P) and total antioxidant activity in the plasma (TAA-P) in 131 male workers from a chloralkali plant exposed to Hg° and 67 non-exposed males (control group). The mRNA expression levels of glutathione peroxidases (GPX1, GPX3), selenoprotein P (SEPP1), thioredoxin reductase 1 (TRXR1), thioredoxin 1 (TRX1), peroxiredoxins (PRDX1, PRDX2) were also examined in the leukocytes of peripheral blood. Hg concentration in the blood (Hg-B) and urine (Hg-U) samples was determined using the thermal decomposition amalgamation/atomic absorption spectrometry (TDA-AAS) method and Se concentrations in plasma (Se-P) and urine (Se-U) using the inductively coupled plasma mass spectrometry (ICP-MS) method. Activities of GPx1-RBC, GPx3-P and TAA-P were determined using the kinetic and spectrophotometric method, respectively. Gene expression analysis was performed using the quantitative Real-Time PCR. The results showed significant higher Hg levels among the Hg°-exposed workers in comparison to control group (12-times higher median for Hg-B and almost 74-times higher median for Hg-U concentration in chloralkali workers). Se-P was also significantly higher (Me (median): 82.85 μg/L (IQR (interquartile range) 72.03-90.28 μg/L) for chloralkali workers vs. Me: 72.74 μg/L (IQR 66.25-80.14 μg/L) for control group; p = 0.0001) but interestingly correlated inversely with Hg-U in chloralkali workers suggesting depletion of the Se protection among the workers with the highest Hg-U concentration. The mRNA level for GPX1, PRXD1 were markedly but significantly higher in the workers compared to the control group. Moreover, concentrations of Hg-B and Hg-U among the workers were significantly positively correlated with the levels of selenoprotein P at both the mRNA and selenoprotein levels. In the multivariate model, after adjusting to cofounders (dental amalgam fillings, age, BMI, job seniority time, smoking), we confirmed that Hg-U concentration was inversely correlated with genes expression of TRXR1. This is the first comprehensive assessment of the impact of occupational exposure of workers to Hg° at both the mRNA and selenoprotein levels, with investigation of fish intake obtained by means of a questionnaire. These findings suggest that exposure to Hg° alters gene expression of the antioxidant enzymes and the level of Se-containing selenoproteins.

Vitamins A and E during Pregnancy and Allergy Symptoms in an Early Childhood—Lack of Association with Tobacco Smoke Exposure

Epidemiological studies have suggested an association between maternal antioxidant levels during pregnancy and development of allergic diseases in their offspring. The aim of the study was to determine plasma vitamins A and E concentration in the 1st trimester of pregnancy, at delivery and in cord blood and to search for a relationship with allergy in up to 2-year-old children who were prenatally exposed or not exposed to tobacco smoke. The study participants included 252 mother-child pairs from Polish Mother and Child Cohort. Vitamin concentrations were measured using the HPLC-UV method, smoking status—as saliva cotinine level using the HPLC-MS/MS technique. Children’s health status was assessed using a questionnaire and pediatricians/allergists examination. Cord plasma vitamin concentrations were significantly lower than their levels in maternal plasma in the 1st trimester and at delivery (p < 0.001). Significantly higher concentrations of vitamin E have been shown to occur during the 1st trimester of pregnancy in plasma of the women who have actively/passively smoked cigarettes compared to the non-smokers (p < 0.02). Multivariate analysis with inclusion of a variety of confounding factors have not indicated any statistically significant associations between β-carotene, vitamins A and E and the risk of food allergy, atopic dermatitis and wheezing in their children up to 2 years of age. The interaction between smoking during pregnancy and vitamins levels on the risk of allergy was not statistically significant (p > 0.4). The relationship between plasma concentration of vitamins A and E, and the risk of allergy in their young children has not been demonstrated.