Ph.D student, UNIFESP
Exploring brain alterations in binge eating disorder
My Ph.D. research explores brain alterations in women who are obese and diagnosed with binge eating disorder. The diagnosis of binge eating disorder is characterized by eating large amounts of food and by not being able to stop, which may lead to excessive weight gain and emotional and physical impairment. What causes and maintains binge eating disorder is unclear, but it has been proposed that binge eating behaviors are related to brain alterations involved in the experiences of pleasure and the ability to suppress responses that are no longer helpful, but how these alterations contribute to binge eating disorder are not established. My research adds to scientific knowledge as it identifies brain alterations associated with binge eating disorder and discovers an impairment in a brain region involved in the critical shift from excessive food consumption to binge eating disorder.
Abstract: Obesity in adolescents is increasingly prevalent and its impact on cardiovascular risk important to determine. Hormonal predictors of cardiovascular risk markers in obese adolescents are not known.Our objective was to examine whether relative GH deficiency and cortisol excess are determinants of increased cardiovascular risk markers in obese teenage girls.A cross-sectional study was conducted at a clinical research center.Thirty girls (15 obese girls and 15 normal-weight controls) 12-18 years old matched for maturity and race.Inflammatory markers of cardiovascular risk including high-sensitivity C-reactive protein (hsCRP), TNF-alpha receptors 1 and 2, E-selectin, soluble intercellular adhesion molecule-1, and IL-6 were analyzed. Leptin, adiponectin, and 24-h urine free cortisol (UFC) were also measured. A GHRH-arginine stimulation test was performed.The hsCRP levels were higher in obese girls than controls (4.63 +/- 4.81 vs. 0.67 +/- 0.72 mg/liter; P = 0.002 after log conversion), as were other markers of cardiovascular risk. Eight of the 15 obese girls but no normal-weight girl had hsCRP higher than 3 mg/liter (P = 0.002). Body mass index sd score was higher than 4.0 in 87.5% of girls with hsCRP higher than 3 mg/liter and no girls with hsCRP less than 3 mg/liter. Girls with hsCRP higher than 3 mg/liter had higher UFC and lower peak GH compared with those with hsCRP less than 3 mg/liter. Peak GH was an important negative predictor of most markers of increased cardiovascular risk. In addition to peak GH, UFC and adiponectin independently predicted hsCRP.Relative GH deficiency and cortisol excess are significant contributors to increased levels of markers of cardiovascular risk in obese adolescent girls.
Pub.: 14 May '09, Pinned: 06 May '18
Abstract: Anorexia nervosa is characterized by low weight, aberrant eating attitudes, body image distortion, and hypogonadism. Anxiety is a common comorbid condition. Estrogen replacement reduces anxiety in animal models, and reported variations in food intake across the menstrual cycle may be related to gonadal steroid levels. The impact of estrogen replacement on anxiety, eating attitudes, and body image has not been reported in anorexia nervosa. We hypothesized that physiologic estrogen replacement would ameliorate anxiety and improve eating attitudes without affecting body image in anorexia nervosa.Girls 13-18 years old with anorexia nervosa (DSM-IV) were randomized to transdermal estradiol (100 μg twice weekly) with cyclic progesterone or placebo patches and pills for 18-months, between 2002 and 2010. The State-Trait Anxiety Inventory for Children (STAIC), the Eating Disorders Inventory-2 (EDI-2), and the Body Shape Questionnaire (BSQ-34) were administered. 72 girls completed these measures at baseline (n=38 [girls receiving estrogen] and n=34 [girls receiving placebo]) and 37 at 18 months (n=20 [girls receiving estrogen] and n=17 [girls receiving placebo]). The primary outcome measure was the change in these scores over 18 months.Estrogen replacement caused a decrease in STAIC-trait scores (-3.05 [1.22] vs. 2.07 [1.73], P=.02), without impacting STAIC-state scores (-1.11 [2.17] vs. 0.20 [1.42], P=.64). There was no effect of estrogen replacement on EDI-2 or BSQ-34 scores. Body mass index (BMI) changes did not differ between groups, and effects of estrogen replacement on STAIC-trait scores persisted after controlling for BMI changes (P=.03). Increases in serum estradiol were significantly associated with decreases in STAIC-trait scores (Spearman ρ = -0.45, P=.03).Estrogen replacement improved trait anxiety (the tendency to experience anxiety) but did not impact eating attitudes or body shape perception.ClinicalTrials.gov identifier: NCT00088153.
Pub.: 12 Sep '13, Pinned: 06 May '18
Abstract: Orexigenic and anorexigenic pathways mediate food intake and may be affected by meal composition. Our objective was to determine whether changes in levels of active ghrelin and peptide YY (PYY) differ in obese vs. normal-weight adolescent girls following specific macronutrient intake and predict hunger and subsequent food intake. We enrolled 26 subjects: 13 obese and 13 normal-weight girls, 12-18 years old, matched for maturity (as assessed by bone age) and race. Subjects were assigned a high-carbohydrate, high-protein, and high-fat breakfast in random order. Active ghrelin and PYY were assessed for 4 h after breakfast and 1 h after intake of a standardized lunch. Hunger was assessed using a standardized visual analog scale (VAS). No suppression in active ghrelin levels was noted following macronutrient intake in obese or normal-weight girls. Contrary to expectations, active ghrelin increased in obese girls following the high-carbohydrate breakfast, and the percent increase was higher than in controls (P = 0.046). Subsequent food intake at lunch was also higher (P = 0.03). Following the high-fat breakfast, but not other breakfasts, percent increase in PYY was lower (P = 0.01) and subsequent lunch intake higher (P = 0.005) in obese compared with normal-weight girls. In obese adolescents, specific intake of high-carbohydrate and high-fat breakfasts is associated with greater increases in ghrelin, lesser increases in PYY, and higher intake at a subsequent meal than in controls. Changes in anorexigenic and orexigenic hormones in obese vs. normal-weight adolescents following high-carbohydrate and high-fat meals may influence hunger and satiety signals and subsequent food intake.
Pub.: 28 Mar '09, Pinned: 06 May '18
Abstract: Although body composition, insulin sensitivity, and lipids are markedly altered in overweight adolescents, hormonal associations with these parameters have not been well characterized. Growth hormone (GH) deficiency and hypercortisolemia predispose to abdominal adiposity and insulin resistance, and GH secretion is decreased in obese adults. We hypothesized that low-peak GH on the GH-releasing hormone (GHRH)-arginine stimulation test and high cortisol in overweight adolescents would be associated with higher regional fat, insulin resistance, and lipids. We examined the following parameters in 15 overweight and 15 bone age-matched control 12- to 18-yr-old girls: 1) body composition using dual-energy X-ray absorptiometry and MR [visceral and subcutaneous adipose tissue at L(4)-L(5) and soleus intramyocellular lipid ((1)H-MR spectroscopy)], 2) peak GH on the GHRH-arginine stimulation test, 3) mean overnight GH and cortisol, 4) 24-h urinary free cortisol (UFC), 5) fasting lipids, and 6) an oral glucose tolerance test. Stepwise regression was the major tool employed to determine relationships between measured parameters. Log peak GH on the GHRH-arginine test was lower (P = 0.03) and log UFC was higher (P = 0.02) in overweight girls. Log mean cortisol (overnight sampling) was associated positively with subcutaneous adipose tissue and, with body mass index standard deviation score, accounted for 92% of its variability, whereas log peak GH and body mass index standard deviation score accounted for 88% of visceral adipose tissue variability and log peak GH for 34% of the intramyocellular lipid variability. Log mean cortisol was independently associated with log homeostasis model assessment of insulin resistance, LDL, and HDL and explained 49-59% of the variability. Our data indicate that lower peak GH and higher UFC in overweight girls are associated with visceral adiposity, insulin resistance, and lipids.
Pub.: 12 Jun '08, Pinned: 06 May '18
Abstract: Anorexia nervosa (AN) is prevalent in adolescents and is associated with decreased bone mineral accrual at a time critical for optimizing bone mass. Low BMD in AN is a consequence of nutritional and hormonal alterations, including hypogonadism and low estradiol levels. Effective therapeutic strategies to improve BMD in adolescents with AN have not been identified. Specifically, high estrogen doses given as an oral contraceptive do not improve BMD. The impact of physiologic estrogen doses that mimic puberty on BMD has not been examined. We enrolled 110 girls with AN and 40 normal-weight controls 12 to 18 years of age of similar maturity. Subjects were studied for 18 months. Mature girls with AN (bone age [BA] ≥15 years, n = 96) were randomized to 100 µg of 17β-estradiol (with cyclic progesterone) or placebo transdermally for 18 months. Immature girls with AN (BA < 15 years, n = 14) were randomized to incremental low-dose oral ethinyl-estradiol (3.75 µg daily from 0 to 6 months, 7.5 µg from 6 to 12 months, 11.25 µg from 12 to 18 months) to mimic pubertal estrogen increases or placebo for 18 months. All BMD measures assessed by dual-energy X-ray absorptiometry (DXA) were lower in girls with AN than in control girls. At baseline, girls with AN randomized to estrogen (AN E + ) did not differ from those randomized to placebo (AN E-) for age, maturity, height, BMI, amenorrhea duration, and BMD parameters. Spine and hip BMD Z-scores increased over time in the AN E+ compared with the AN E- group, even after controlling for baseline age and weight. It is concluded that physiologic estradiol replacement increases spine and hip BMD in girls with AN.
Pub.: 24 Jun '11, Pinned: 06 May '18