Insulin sensitivity as a predictor of longitudinal changes on body mass index in Brazilian adolescents.

OBJECTIVES: We aimed to investigate the effect of insulin sensitivity and insulin resistance status at baseline on longitudinal body mass index, and the possible effect modification by sex. METHODS: This is a secondary analysis of a randomized intervention community trial, in which a subgroup of 84 adolescents, aged between 10 and 12 years, were analyzed. Body weight, height, and body mass index (BMI) were determined before and after 8 months of follow-up. Glucose and serum insulin were examined at baseline and IR was defined based on the homeostasis model assessment-insulin resistance (HOMA-IR), with a cutoff >2.5 for both genders. Linear mixed-effects models were performed to evaluate the influence of HOMA-IR at baseline on BMI changes over time. Models were adjusted for age, pubertal stage, and stratified by sex. RESULTS: The sample comprised 65.4% of girls and the prevalence of overweight/obesity was 54.7% among girls and 50.0% among boys. The overall prevalence of IR was 75.3%, of which 60.7% for boys and 83.0% for girls. We found an interaction effect by sex (p = .004) for HOMA-IR as a continuous variable, with a decreased BMI rate of change among boys (ß = -0.13; p = .03) but not for girls (ß = +0.03; p = .36). Longitudinal BMI changes considering IR status at baseline (IR vs. non-IR) did not demonstrate any statistically significant difference for both boys (-0.1 vs. +0.4; p = .28) and girls (+0.7 vs. +1.0; p = .44). CONCLUSION: Increased HOMA-IR values at baseline were associated with greater BMI reduction over time among boys but not girls, with no influence of IR status.

Effect of physical exercise on spontaneous physical activity energy expenditure and energy intake in overweight adults (the EFECT study): a study protocol for a randomized controlled trial.

BACKGROUND: Physical exercise interventions have been extensively advocated for the treatment of obesity; however, clinical trials evaluating the effectiveness of exercise interventions on weight control show controversial results. Compensatory mechanisms through a decrease in energy expenditure and/or an increase in caloric consumption is a possible explanation. Several physiological mechanisms involved in the energy balance could explain compensatory mechanisms, but the influences of physical exercise on these adjustments are still unclear. Therefore, the present trial aims to evaluate the effects of exercise on non-exercise physical activity energy expenditure, energy intake and appetite sensations among active overweight/obese adults, as well as, to investigate hormonal changes associated with physical exercise. METHODS: This study is a randomized controlled trial with parallel, three-group experimental arms. Eighty-one overweight/obese adults will be randomly allocated (1:1:1 ratio) to a vigorous exercise group, moderate exercise group or control group. The trial will be conducted at a military institution and the intervention groups will be submitted to exercise sessions in the evening, three times a week for 65 min, during a 2-week period. The primary outcome will be total spontaneous physical activity energy expenditure during a 2-week period. Secondary outcomes will be caloric intake, appetite sensations and laboratorial biomarkers. Intention-to-treat analysis will be performed using linear mixed-effects models to evaluate the effect of treatment-by-time interaction on primary and secondary outcomes. Data analysis will be performed using SAS 9.3 and statistical significance will be set at p < 0.05. DISCUSSION: The results of the present study will help to understand the effect of physical exercise training on subsequent non-exercise physical activity, appetite and energy intake as well as understand the physiological mechanisms underlying a possible compensatory phenomenon, supporting the development of more effective interventions for prevention and treatment of obesity. TRIAL REGISTRATION: Physical Exercise and Energy Balance trial registry, trial registration number: NCT 03138187 . Registered on 30 April 2017.

Impaired mitochondrial function and reduced viability in bone marrow cells of obese mice.

Bone marrow cells (BMCs) are the main type of cells used for transplantation therapies. Obesity, a major world health problem, has been demonstrated to affect various tissues, including bone marrow. This could compromise the success of such therapies. One of the main mechanisms underlying the pathogenesis of obesity is mitochondrial dysfunction, and recent data have suggested an important role for mitochondrial metabolism in the regulation of stem cell proliferation and differentiation. Since the potential use of BMCs for clinical therapies depends on their viability and capacity to proliferate and/or differentiate properly, the analysis of mitochondrial function and cell viability could be important approaches for evaluating BMC quality in the context of obesity. We therefore compared BMCs from a control group (CG) and an obese group (OG) of mice and evaluated their mitochondrial function, proliferation capacity, apoptosis, and levels of proteins involved in energy metabolism. BMCs from OG had increased apoptosis and decreased proliferation rates compared with CG. Mitochondrial respiratory capacity, biogenesis, and the coupling between oxidative phosphorylation and ATP synthesis were significantly decreased in OG compared with CG, in correlation with increased levels of uncoupling protein 2 and reduced peroxisome proliferator-activated receptor-coactivator 1α content. OG also had decreased amounts of the glucose transporter GLUT-1 and insulin receptor (IRß). Thus, Western-diet-induced obesity leads to mitochondrial dysfunction and reduced proliferative capacity in BMCs, changes that, in turn, might compromise the success of therapies utilizing these cells.

Changes in body weight, C-reactive protein, and total adiponectin in non-obese women after 12 months of a small-volume, home-based exercise program.

OBJECTIVE: Our objective was to evaluate the effects of small-volume, home-based exercise combined with slight caloric restriction on the inflammatory markers C-reactive protein and adiponectin. METHODS: In total, 54 women were randomly assigned to one of two groups for exercise intervention: the control or home-based exercise groups. Weight, waist and hip circumferences, and inflammatory markers were measured at baseline and after 6 and 12 months. Women allocated to the home-based exercise group received a booklet explaining the physical exercises to be practiced at home at least 3 times per week, 40 minutes per session, at low-to-moderate intensity. All participants received dietary counseling aimed at reducing caloric intake by 100-300 calories per day, with a normal distribution of macro-nutrients (26-28% of energy as fat). Clinicaltrials.gov: NCT01206413 RESULTS: The home-based exercise group showed a significantly greater reduction in weight and body mass index at six months, but no difference between groups was observed thereafter. With regard to the inflammatory markers, a greater but non-statistically significant reduction was found for C-reactive protein in the home-based exercise group at six months; however, this difference disappeared after adjusting for weight change. No differences in adiponectin were found at the 6- or 12-month follow-up. CONCLUSION: Small-volume, home-based exercise did not promote changes in inflammatory markers independent of weight change.

Ghrelin and leptin modulate the feeding behaviour of the hawksbill turtle Eretmochelys imbricata during nesting season.

Female sea turtles have rarely been observed foraging during the nesting season. This suggests that prior to their migration to nesting beaches the females must store sufficient energy and nutrients at their foraging grounds and must be physiologically capable of undergoing months without feeding. Leptin (an appetite-suppressing protein) and ghrelin (a hunger-stimulating peptide) affect body weight by influencing energy intake in all vertebrates. We investigated the levels of these hormones and other physiological and nutritional parameters in nesting hawksbill sea turtles in Rio Grande do Norte State, Brazil, by collecting consecutive blood samples from 41 turtles during the 2010-2011 and 2011-2012 reproductive seasons. We found that levels of serum leptin decreased over the nesting season, which potentially relaxed suppression of food intake and stimulated females to begin foraging either during or after the post-nesting migration. Concurrently, we recorded an increasing trend in ghrelin, which may have stimulated food intake towards the end of the nesting season. Both findings are consistent with the prediction that post-nesting females will begin to forage, either during or immediately after their post-nesting migration. We observed no seasonal trend for other physiological parameters (values of packed cell volume and serum levels of alanine aminotransferase, aspartate aminotransferase, alkaline phosphatase, γ-glutamyl transferase, low-density lipoprotein, and high-density lipoprotein). The observed downward trends in general serum biochemistry levels were probably due to the physiological challenge of vitellogenesis and nesting in addition to limited energy resources and probable fasting.

Changes in body weight, C-reactive protein, and total adiponectin in non-obese women after 12 months of a small-volume, home-based exercise program

OBJECTIVE: Our objective was to evaluate the effects of small-volume, home-based exercise combined with slight caloric restriction on the inflammatory markers C-reactive protein and adiponectin. METHODS: In total, 54 women were randomly assigned to one of two groups for exercise intervention: the control or home-based exercise groups. Weight, waist and hip circumferences, and inflammatory markers were measured at baseline and after 6 and 12 months. Women allocated to the home-based exercise group received a booklet explaining the physical exercises to be practiced at home at least 3 times per week, 40 minutes per session, at low-to-moderate intensity. All participants received dietary counseling aimed at reducing caloric intake by 100-300 calories per day, with a normal distribution of macro-nutrients (26-28% of energy as fat). Clinicaltrials.gov: NCT01206413 RESULTS: The home-based exercise group showed a significantly greater reduction in weight and body mass index at six months, but no difference between groups was observed thereafter. With regard to the inflammatory markers, a greater but non-statistically significant reduction was found for C-reactive protein in the home-based exercise group at six months; however, this difference disappeared after adjusting for weight change. No differences in adiponectin were found at the 6- or 12-month follow-up. CONCLUSION: Small-volume, home-based exercise did not promote changes in inflammatory markers independent of weight change. .

Appetite-related hormone levels in obese women with and without binge eating behavior / Hormônios reguladores do apetite em mulheres obesas com e sem compulsão alimentar

OBJECTIVE: The aim of this study was to evaluate serum levels of appetite-related hormones (peptide YY3-36, total ghrelin, leptin and insulin) before and after consumption of a meal in obese women with and without binge eating episodes and normal weight women. METHODS: Twenty-five women aged 32-50 years were invited to participate in this study, including 9 normal weight women without binge eating episodes (20-25kg/m², group 1), 9 obese women with binge eating episodes (³30kg/m², group 2), and 7 obese women without binge eating episodes (group 3). Four blood samples were collected from each participant, one being 60 minutes before and three being 15, 45 and 90 minutes after a meal. The composition of the meal was 55 percent carbohydrates, 15 percent protein and 30 percent lipids. RESULTS: Group 3 presented increased HOMA-IR (M=2.5, SD=1.04) when compared with group 1 (M=1.5, SD=0.53) and group 2 (M=1.8, SD=0.58), p=0.04. Body mass index (p<0.0001), leptin (p<0.0001) and insulin (p=0.01) were higher in group 3 than in the other groups before and after the meal. Additionally, total ghrelin (p=0.003) and PYY3-36 (p=0.02) levels were lower in group 2 than in the other groups before and after the meal. After adjustment for body mass index, only the lower PYY3-36 level of group 2 remained statistically different from the other groups (p=0.01). CONCLUSION: Our study suggests that lower levels of PYY 3-36 are associated with binge eating in obese women.

OBJETIVO: O objetivo deste estudo foi avaliar, antes e após a refeição, as concentrações séricas de hormônios ligados ao controle do apetite (peptídeo YY3-36, grelina total, leptina e insulina) em mulheres obesas com e sem episódios de compulsão alimentar e compará-las às mulheres de peso normal. MÉTODOS: Vinte e cinco mulheres com idade entre 32 e 50 anos foram convidadas a participar deste estudo, incluindo 9 mulheres com peso normal (20-25kg/m²) sem episódios de compulsão alimentar (grupo 1), 9 mulheres obesas (³30 kg/m²) com episódios de compulsão alimentar (grupo 2) e 7 mulheres obesas sem episódios de compulsão alimentar (grupo 3). Foram coletadas quatro amostras de sangue pós-prandiais a 60 minutos (1 hora antes), bem como 15, 45 e 90 minutos após uma refeição composta de 55 por cento de carboidratos, 15 por cento de proteínas e 30 por cento de lipídeos. RESULTADOS: O maior HOMA-IR foi observado no grupo 3 (M=2,5, DP=1,04) quando comparado ao grupo 1 (M=1,5, DP=0,53) e ao grupo 2 (M=1,8, DP=0,58), p=0,04. O índice de massa corporal (p<0,0001), a leptina (p<0,0001) e a insulina (p=0,01) foram maiores no grupo 3 antes e após a refeição. A grelina total (p=0,003) e o PYY3-36 (p=0,02) foram menores no grupo 2 antes e após a refeição. Após o ajuste do índice de massa corporal, apenas a baixa concentração de PYY3-36 no grupo 2 manteve-se estatisticamente diferente entre os grupos (p=0,01). CONCLUSÃO: Este estudo sugere que níveis baixos do PYY-3-36 estejam associados à compulsão alimentar em mulheres obesas.

Leptin/adiponectin ratio in obese women with and without binge eating disorder.

BACKGROUND: Adipose tissue-derived hormones are involved in the pathophysiology of eating disorders and other mental disorders. Studies have suggested that the serum leptin/adiponectin ratio is highly correlated with BMI. Furthermore, it is associated with a number of metabolic processes and inflammatory markers that are involved in obesity and mental disorders, such as the physiopathology of binge eating disorder (BED). We investigated whether variations in leptin and adiponectin serum concentrations differed between adult women with and without BED before and after a meal. METHODS: The study group was composed of 8 normal weight women (20-25 kg/m2) without BED, 8 obese women (>/=30 kg/m2) with BED, and 7 obese women without BED (non-BED). Blood samples were collected before and after the consumption of a meal composed of 55% carbohydrates, 15% protein, and 30% lipids. RESULTS: Body mass index (p<0.0001), leptin (p<0.0001) and the leptin/adiponectin ratio (p<0.0001) were higher in obese non-BED women than in obese BED and normal weight groups. Adiponectin (p=0.01) concentrations were lower in the obese BED group than in the other groups before and after the meal. CONCLUSIONS: The hypoadiponectinemia followed by the altered levels of leptin in obese BED woman may predispose these subjects to an inadequate energy balance, which could promote weight gain and an increased food intake in woman that may contribute to obesity and binge eating in these subjects.