In utero exposure to maternal diabetes or hypertension and childhood hypothalamic gliosis.

Exposure to maternal diabetes (DM) or hypertension (HTN) during pregnancy impacts offspring metabolic health in childhood and beyond. Animal models suggest that induction of hypothalamic inflammation and gliosis in the offspring's hypothalamus is a possible mechanism mediating this effect. We tested, in children, whether in utero exposures to maternal DM or HTN were associated with mediobasal hypothalamic (MBH) gliosis as assessed by brain magnetic resonance imaging (MRI). The study included a subsample of 306 children aged 9-11 years enrolled in the ABCD Study®; 49 were DM-exposed, 53 were HTN-exposed, and 204 (2:1 ratio) were age- and sex-matched children unexposed to DM and/or HTN in utero. We found a significant overall effect of group for the primary outcome of MBH/amygdala (AMY) T2 signal ratio (F(2,300):3.51, p = 0.03). Compared to unexposed children, MBH/AMY T2 signal ratios were significantly higher in the DM-exposed (ß:0.05, p = 0.02), but not the HTN-exposed children (ß:0.03, p = 0.13), findings that were limited to the MBH and independent of adiposity. We concluded that children exposed to maternal DM in utero display evidence of hypothalamic gliosis, suggesting that gestational DM may have a distinct influence on offspring's brain development and, by extension, children's long-term metabolic health.

Central androgen action reverses hypothalamic astrogliosis and atherogenic risk factors induced by orchiectomy and high-fat diet feeding in male mice.

Hypogonadism in males confers elevated cardiovascular disease (CVD) risk by unknown mechanisms. Recent radiological evidence suggests that low testosterone (T) is associated with mediobasal hypothalamic (MBH) gliosis, a central nervous system (CNS) cellular response linked to metabolic dysfunction. To address mechanisms linking CNS androgen action to CVD risk, we generated a hypogonadal, hyperlipidemic mouse model with orchiectomy (ORX) combined with hepatic PCSK9 overexpression. After 4 wk of high-fat, high-sucrose diet (HFHS) consumption, despite equal body weights and glucose tolerance, androgen-deficient ORX mice had a more atherogenic lipid profile and increased liver and leukocyte inflammatory signaling compared with sham-operated control mice. Along with these early CVD risk indicators, ORX markedly amplified HFHS-induced astrogliosis in the MBH. Transcriptomic analysis further revealed that ORX and high-fat diet feeding induced upregulation of inflammatory pathways and downregulation of metabolic pathways in hypothalamic astrocytes. To interrogate the role of sex steroid signaling in the CNS in cardiometabolic risk and MBH inflammation, central infusion of T and dihydrotestosterone (DHT) was performed on ORX mice. Central DHT prevented MBH astrogliosis and reduced the liver inflammatory signaling and monocytosis induced by HFHS and ORX; T had a partial protective effect. Finally, a cross-sectional study in 41 adult men demonstrated a positive correlation between radiological evidence of MBH gliosis and plasma lipids. These findings demonstrate that T deficiency in combination with a Western-style diet promotes hypothalamic gliosis concomitant with increased atherogenic risk factors and provide supportive evidence for regulation of lipid metabolism and cardiometabolic risk determinants by the CNS action of sex steroids.NEW & NOTEWORTHY This study provides evidence that hypothalamic gliosis is a key early event through which androgen deficiency in combination with a Western-style diet might lead to cardiometabolic dysregulation in males. Furthermore, this work provides the first evidence in humans of a positive association between hypothalamic gliosis and LDL-cholesterol, advancing our knowledge of CNS influences on CVD risk progression.

Child neurobiology impacts success in family-based behavioral treatment for children with obesity.

BACKGROUND AND OBJECTIVES: Family-based behavioral treatment (FBT) is the recommended treatment for children with common obesity. However, there is a large variability in short- and long-term treatment response, and mechanisms for unsuccessful treatment outcomes are not fully understood. In this study, we tested if brain response to visual food cues among children with obesity before treatment predicted weight or behavioral outcomes during a 6-month behavioral weight management program and/or long-term relative weight maintenance over a 1-year follow-up period. SUBJECTS AND METHODS: Thirty-seven children with obesity (age 9-11 years, 62% male) who entered active FBT (attended two or more sessions) and had outcome data. Brain activation was assessed at pretreatment by functional magnetic resonance imaging across an a priori set of appetite-processing brain regions that included the ventral and dorsal striatum, mOFC, amygdala, substantia nigra/ventral tegmental area, and insula in response to viewing food images before and after a standardized meal. RESULTS: Children with more robust reductions in brain activation to high-calorie food cue images following a meal had greater declines in BMI z-score during FBT (r = 0.42; 95% CI: 0.09, 0.66; P = 0.02) and greater improvements in Healthy Eating Index scores (r = -0.41; 95% CI: -0.67, -0.06; P = 0.02). In whole-brain analyses, greater activation in the ventromedial prefrontal cortex, specifically by high-calorie food cues, was predictive of better treatment outcomes (whole-brain cluster corrected P = 0.02). There were no significant predictors of relative weight maintenance, and initial behavioral or hormonal measures did not predict FBT outcomes. CONCLUSIONS: Children's brain responses to a meal prior to obesity treatment were related to treatment-based weight outcomes, suggesting that neurophysiologic factors and appetitive drive, more so than initial hormone status or behavioral characteristics, limit intervention success.

Salience network connectivity is reduced by a meal and influenced by genetic background and hypothalamic gliosis.

BACKGROUND/OBJECTIVES: The salience network (SN) comprises brain regions that evaluate cues in the external environment in light of internal signals. We examined the SN response to meal intake and potential genetic and acquired influences on SN function. SUBJECTS/METHODS: Monozygotic (MZ; 40 pairs) and dizygotic (15 pairs) twins had body composition and plasma metabolic profile evaluated (glucose, insulin, leptin, ghrelin, and GLP-1). Twins underwent resting-state functional magnetic resonance imaging (fMRI) scans before and after a standardized meal. The strength of SN connectivity was analyzed pre- and post-meal and the percentage change elicited by a meal was calculated. A multi-echo T2 MRI scan measured T2 relaxation time, a radiologic index of gliosis, in the mediobasal hypothalamus (MBH) and control regions. Statistical approaches included intraclass correlations (ICC) to investigate genetic influences and within-pair analyses to exclude genetic confounders. RESULTS: SN connectivity was reduced by a meal ingestion (ß = -0.20; P < 0.001). Inherited influences on both pre- and post-meal connectivity were present (ICC MZ twins 26%, P < 0.05 and 47%, P < 0.001, respectively), but not percentage change in response to the meal. SN connectivity in response to a meal did not differ between participants with obesity and of normal weight (χ2(1) = 0.93; P = 0.33). However, when participants were classified as having high or low signs of MBH gliosis, the high MBH gliosis group failed to reduce the connectivity in response to a meal (z = -1.32; P = 0.19). Excluding genetic confounders, the percentage change in SN connectivity by a meal correlated to body fat percentage (r = 0.24; P < 0.01). CONCLUSIONS: SN connectivity was reduced by a meal, indicating potential participation of the SN in control of feeding. The strength of SN connectivity is inherited, but the degree to which SN connectivity is reduced by eating appears to be influenced by adiposity and the presence of hypothalamic gliosis.

Radiologic evidence that hypothalamic gliosis is improved after bariatric surgery in obese women with type 2 diabetes.

BACKGROUND/OBJECTIVES: Hypothalamic neurons play a major role in the control of body mass. Obese subjects present radiologic signs of gliosis in the hypothalamus, which may reflect the damage or loss of neurons involved in whole-body energy homeostasis. It is currently unknown if hypothalamic gliosis (1) differs between obese nondiabetic (ND) and obese diabetic subjects (T2D) or (2) is modified by extensive body mass reduction via Roux-n-Y gastric bypass (RYGB). SUBJECTS/METHODS: Fifty-five subjects (all female) including lean controls (CT; n = 13), ND (n = 28), and T2D (n = 14) completed at least one study visit. Subjects underwent anthropometrics and a multi-echo MRI sequence to measure mean bilateral T2 relaxation time in the mediobasal hypothalamus (MBH) and two reference regions (amygdala and putamen). The obese groups underwent RYGB and were re-evaluated 9 months later. Analyses were by linear mixed models. RESULTS: Analyses of T2 relaxation time at baseline showed a group by region interaction only in the MBH (P < 0.0001). T2D had longer T2 relaxation times compared to either CT or ND groups. To examine the effects of RYGB on hypothalamic gliosis a three-way (group by region by time) mixed effects model adjusted for age was executed. Group by region (P < 0.0001) and region by time (P = 0.0005) interactions were significant. There was a reduction in MBH relaxation time by RYGB, and, although the T2D group still had higher T2 relaxation time overall compared to the ND group, the T2D group had significantly lower T2 relaxation time after surgery and the ND group showed a trend. The degree of reduction in MBH T2 relaxation time by RYGB was unrelated to clinical outcomes. CONCLUSION: T2 relaxation times, a marker of hypothalamic gliosis, are higher in obese women with T2D and are reduced by RYGB-induced weight loss.

Effects of multiple cycles of weight loss and regain on the body weight regulatory system in rats.

We studied the effects of multiple cycles of weight loss and regain on the defended body weight in rats. Thirty-six male Wistar rats were divided into three weight-matched groups: weight cyclers (n = 18), ad libitum-fed controls (n = 9), and maturity controls (n = 9). Cyclers underwent four rounds of 20% weight loss from 50% caloric restriction, each cycle followed by recovery to stable plateau weight on ad libitum feeding. Controls ate ad libitum. Maturity controls ate ad libitum and then weight cycled the final two rounds to evaluate the effect of age in later cycles. Cyclers' postdiet plateau weight became progressively lower than that of controls. With each weight loss, ghrelin increased, while insulin and leptin decreased; the magnitude of these changes did not differ across cycles. After four rounds, cyclers' weight (504 ± 7 vs. 540 ± 22 g; P < 0.05) and percent body fat (11.7 vs. 15.2%; P < 0.05) were lower than in controls. After a 4-mo follow-up period of ad libitum feeding, cyclers maintained a lower total fat-pad mass versus controls (8.6 ± 0.5 vs. 15.9 ± 3.6 g; P < 0.01) and a lower glucose area-under-the-curve on oral glucose tolerance tests (P < 0.05). Repeated weight-loss cycles exerted positive effects, durably lowering defended levels of body adiposity and improving glucose tolerance.

Effects of Anxiety on Caloric Intake and Satiety-Related Brain Activation in Women and Men.

OBJECTIVE: To test the relationship of anxiety to caloric intake and food cue perception in women and men. METHODS: Fifty-five twins (26 complete, 3 incomplete pairs; 51% women) underwent 2 functional magnetic resonance imaging (fMRI) scans (before and after a standardized meal) and then ate at an ad libitum buffet to objectively assess food intake. State and trait anxiety were assessed using the State-Trait Anxiety Inventory. During the fMRI scans, participants viewed blocks of fattening and nonfattening food images, and nonfood objects. RESULTS: In women, higher trait anxiety was associated with a higher body mass index (BMI) (r = 0.40, p = .010). Trait anxiety was positively associated with kilocalories consumed at the buffet (r = 0.53, p = .005) and percent kilocalories consumed from fat (r = 0.30, p = .006), adjusted for BMI. In within-pair models, which control for shared familial and genetic factors, higher trait anxiety remained associated with kilocalories consumed at the buffet (p = .66, p = .014), but not with BMI. In men, higher state anxiety was related to macronutrient choices, but not to total caloric intake or BMI. FMRI results revealed that women with high trait anxiety did not suppress activation by fattening food cues across brain regions associated with satiety perception after eating a standardized meal (low anxiety, mean difference = -15.4, p < .001; high anxiety, mean difference = -1.53, p = .82, adjusted for BMI). CONCLUSIONS: In women, trait anxiety may promote excess caloric consumption through altered perception of high-calorie environmental food cues, placing women with genetic predispositions toward weight gain at risk of obesity. TRIAL REGISTRATION: Clinicaltrials.govidentifier:NCT02483663.

Initial evidence that GLP-1 receptor blockade fails to suppress postprandial satiety or promote food intake in humans.

Glucagon-like peptide 1 (GLP-1) has incretin effects that are well-documented, but the independent role of GLP-1 action in human satiety perception is debated. We hypothesized that blockade of GLP-1 receptors would suppress postprandial satiety and increase voluntary food intake. After an overnight fast, eight normal weight participants (seven men, BMI 19-24.7 kg/m(2), age 19-29 year) were enrolled in a double-blind, placebo-controlled, randomized crossover study of the GLP-1 antagonist Exendin-[9-39] (Ex-9) to determine if the satiating effects of a meal are dependent on GLP-1 signaling in humans. Following a fasting blood draw, iv infusion of Ex-9 (600-750 pmol/kg/min) or saline began. Thirty minutes later, subjects consumed a standardized breakfast followed 90 min later (at the predicted time of maximal endogenous circulating GLP-1) by an ad libitum buffet meal to objectively measure satiety. Infusions ended once the buffet meal was complete. Visual analog scale ratings of hunger and fullness and serial assessments of plasma glucose, insulin, and GLP-1 concentrations were done throughout the experiment. Contrary to the hypothesis, during Ex-9 infusion subjects reported a greater decrease in hunger due to consumption of the breakfast (Ex-9 -62 ± 5; placebo -41 ± 9; P=0.01) than during placebo. There were no differences in ad libitum caloric intake between Ex-9 and placebo. Ex-9 increased glucose, insulin, and endogenous GLP-1, which may have counteracted any effects of Ex-9 infusion to block satiety signaling. Blockade of GLP-1 receptors failed to suppress subjective satiety following a standardized meal or increase voluntary food intake in healthy, normal-weight subjects.

Associations of radiologic characteristics of the neonatal hypothalamus with early life adiposity gain.

BACKGROUND: The mediobasal hypothalamus (MBH) is a key brain area for regulation of energy balance. Previous neuroimaging studies suggest that T2-based signal properties indicative of cellular inflammatory response (gliosis) are present in adults and children with obesity, and predicts greater adiposity gain in children at risk of obesity. OBJECTIVES/METHODS: The current study aimed to extend this concept to the early life period by considering if, in full-term healthy neonates (up to n = 35), MRI evidence of MBH gliosis is associated with changes in early life (neonatal to six months) body fat percentage measured by DXA. RESULTS: In this initial study, neonatal T2 signal in the MBH was positively associated with six-month changes in body fat percentage. CONCLUSION: This finding supports the notion that underlying processes in the MBH may play a role in early life growth and, by extension, childhood obesity risk.

Longer T(2) relaxation time is a marker of hypothalamic gliosis in mice with diet-induced obesity.

A hallmark of brain injury from infection, vascular, neurodegenerative, and other disorders is the development of gliosis, which can be detected by magnetic resonance imaging (MRI). In rodent models of diet-induced obesity (DIO), high-fat diet (HFD) consumption rapidly induces inflammation and gliosis in energy-regulating regions of the mediobasal hypothalamus (MBH), and recently we reported MRI findings suggestive of MBH gliosis in obese humans. Thus, noninvasive imaging may obviate the need to assess MBH gliosis using histopathological end points, an obvious limitation to human studies. To investigate whether quantitative MRI is a valid tool with which to measure MBH gliosis, we performed analyses, including measurement of T(2) relaxation time from high-field MR brain imaging of mice fed HFD and chow-fed controls. Mean bilateral T(2) relaxation time was prolonged significantly in the MBH, but not in the thalamus or cortex, of HFD-fed mice compared with chow-fed controls. Histological analysis confirmed evidence of increased astrocytosis and microglial accumulation in the MBH of HFD-fed mice compared with controls, and T(2) relaxation times in the right MBH correlated positively with mean intensity of glial fibrillary acidic protein staining (a marker of astrocytes) in HFD-fed animals. Our findings indicate that T(2) relaxation time obtained from high-field MRI is a useful noninvasive measurement of HFD-induced gliosis in the mouse hypothalamus with potential for translation to human studies.

Vitamin D deficiency in obese rats exacerbates nonalcoholic fatty liver disease and increases hepatic resistin and Toll-like receptor activation.

UNLABELLED: Childhood obesity is associated with type 2 diabetes mellitus and nonalcoholic fatty liver disease (NAFLD). Recent studies have found associations between vitamin D deficiency (VDD), insulin resistance (IR), and NAFLD among overweight children. To further explore mechanisms mediating these effects, we fed young (age 25 days) Sprague-Dawley rats with a low-fat diet (LFD) alone or with vitamin D depletion (LFD+VDD). A second group of rats was exposed to a Westernized diet (WD: high-fat/high-fructose corn syrup) that is more typically consumed by overweight children, and was either replete (WD) or deficient in vitamin D (WD+VDD). Liver histology was assessed using the nonalcoholic steatohepatitis (NASH) Clinical Research Network (CRN) scoring system and expression of genes involved in inflammatory pathways were measured in liver and visceral adipose tissue after 10 weeks. In VDD groups, 25-OH-vitamin D levels were reduced to 29% (95% confidence interval [CI]: 23%-36%) compared to controls. WD+VDD animals exhibited significantly greater hepatic steatosis compared to LFD groups. Lobular inflammation as well as NAFLD Activity Score (NAS) were higher in WD+VDD versus the WD group (NAS: WD+VDD 3.2 ± 0.47 versus WD 1.50 ± 0.48, P < 0.05). Hepatic messenger RNA (mRNA) levels of Toll-like receptors (TLR)2, TLR4, and TLR9, as well as resistin, interleukins (IL)-1ß, IL-4, and IL-6 and oxidative stress marker heme oxygenase (HO)-1, were higher in WD+VDD versus WD animals (P < 0.05). Logistic regression analyses showed significant associations between NAS score and liver mRNA levels of TLRs 2, 4, and 9, endotoxin receptor CD14, as well as peroxisome proliferator activated receptor (PPAR)γ, and HO-1. CONCLUSION: VDD exacerbates NAFLD through TLR-activation, possibly by way of endotoxin exposure in a WD rat model. In addition it causes IR, higher hepatic resistin gene expression, and up-regulation of hepatic inflammatory and oxidative stress genes.

The Significance of Hypothalamic Inflammation and Gliosis for the Pathogenesis of Obesity in Humans.

Accumulated preclinical literature demonstrates that hypothalamic inflammation and gliosis are underlying causal components of diet-induced obesity in rodent models. This review summarizes and synthesizes available translational data to better understand the applicability of preclinical findings to human obesity and its comorbidities. The published literature in humans includes histopathologic analyses performed postmortem and in vivo neuroimaging studies measuring indirect markers of hypothalamic tissue microstructure. Both support the presence of hypothalamic inflammation and gliosis in children and adults with obesity. Findings predominantly point to tissue changes in the region of the arcuate nucleus of the hypothalamus, although findings of altered tissue characteristics in whole hypothalamus or other hypothalamic regions also emerged. Moreover, the severity of hypothalamic inflammation and gliosis has been related to comorbid conditions, including glucose intolerance, insulin resistance, type 2 diabetes, and low testosterone levels in men, independent of elevated body adiposity. Cross-sectional findings are augmented by a small number of prospective studies suggesting that a greater degree of hypothalamic inflammation and gliosis may predict adiposity gain and worsening insulin sensitivity in susceptible individuals. In conclusion, existing human studies corroborate a large preclinical literature demonstrating that hypothalamic neuroinflammatory responses play a role in obesity pathogenesis. Extensive or permanent hypothalamic tissue remodeling may negatively affect the function of neuroendocrine regulatory circuits and promote the development and maintenance of elevated body weight in obesity and/or comorbid endocrine disorders.

Impaired Brain Satiety Responses After Weight Loss in Children With Obesity.

CONTEXT: Obesity interventions often result in increased motivation to eat. OBJECTIVE: We investigated relationships between obesity outcomes and changes in brain activation by visual food cues and hormone levels in response to obesity intervention by family-based behavioral treatment (FBT). METHODS: Neuroimaging and hormone assessments were conducted before and after 24-week FBT intervention in children with obesity (OB, n = 28), or children of healthy weight without intervention (HW, n = 17), all 9- to 11-year-old boys and girls. We evaluated meal-induced changes in neural activation to high- vs low-calorie food cues across appetite-processing brain regions and gut hormones. RESULTS: Among children with OB who underwent FBT, greater declines of BMI z-score were associated with lesser reductions after the FBT intervention in meal-induced changes in neural activation to high- vs low-calorie food cues across appetite-processing brain regions (P < 0.05), and the slope of relationship was significantly different compared with children of HW. In children with OB, less reduction in brain responses to a meal from before to after FBT was associated with greater meal-induced reduction in ghrelin and increased meal-induced stimulation in peptide YY and glucagon-like peptide-1 (all P < 0.05). CONCLUSION: In response to FBT, adaptations of central satiety responses and peripheral satiety-regulating hormones were noted. After weight loss, changes of peripheral hormone secretion support weight loss, but there was a weaker central satiety response. The findings suggest that even when peripheral satiety responses by gut hormones are intact, the central regulation of satiety is disturbed in children with OB who significantly improve their weight status during FBT, which could favor future weight regain.

General and Food-Specific Impulsivity and Inhibition Related to Weight Management.

Background: Understanding child characteristics that relate to weight management treatment outcome could help identify opportunities for intervention innovation or tailoring. The limited evidence available is inconsistent regarding whether and which aspects of children's general or food-specific impulsivity and inhibition relate to treatment outcomes. Methods: Children with (n = 54) and without obesity (n = 22) were compared on various measures of impulsivity and inhibition. Children with obesity (n = 40) then completed family-based treatment for weight management. Analyses examined associations between baseline children's impulsivity and inhibition and child weight status change (BMI z-score) and between treatment-based changes in impulsivity and inhibition and weight status change, with and without adjustment by baseline functional magnetic resonance imaging-measured appetitive drive. Results: Children with obesity scored more poorly on some, but not all, measures of impulsivity and inhibition than children without obesity. Lower baseline general inhibition and greater parent-report of child impulsivity were associated (independently) with greater improvements in child weight status, with modest attenuation after appetite drive adjustment. Children improved task-based general inhibition during treatment. Improvements in general inhibition and snack food discounting were associated with better child weight outcomes, although adjusting for baseline values attenuated these associations. Conclusions: Children with obesity having greater initial impulsivity had better weight outcomes in treatment even after adjusting for initial appetitive drive. In contrast, improvements in task-based inhibition and food-related discounting during treatment were also related to better outcomes. Research is needed on innovative approaches to better address impulsivity and inhibition in children's weight management. Clinical Trial Registration number: NCT02484976.

Evidence That Hypothalamic Gliosis Is Related to Impaired Glucose Homeostasis in Adults With Obesity.

OBJECTIVE: Preclinical research implicates hypothalamic glial cell responses in the pathogenesis of obesity and type 2 diabetes (T2D). In the current study we sought to translate such findings to humans by testing whether radiologic markers of gliosis in the mediobasal hypothalamus (MBH) were greater in individuals with obesity and impaired glucose homeostasis or T2D. RESEARCH DESIGN AND METHODS: Using cross-sectional and prospective cohort study designs, we applied a validated quantitative MRI approach to assess gliosis in 67 adults with obesity and normal glucose tolerance, impaired glucose tolerance (IGT), or T2D. Assessments of glucose homeostasis were conducted via oral glucose tolerance tests (OGTT) and ß-cell modeling. RESULTS: We found significantly greater T2 relaxation times (a marker of gliosis by MRI), that were independent of adiposity, in the groups with IGT and T2D as compared with the group with normal glucose tolerance. Findings were present in the MBH, but not control regions. Moreover, positive linear associations were present in the MBH but not control regions between T2 relaxation time and glucose area under the curve during an OGTT, fasting glucose concentrations, hemoglobin A1c, and visceral adipose tissue mass, whereas negative linear relationships were present in the MBH for markers of insulin sensitivity and ß-cell function. In a prospective cohort study, greater MBH T2 relaxation times predicted declining insulin sensitivity over 1 year. CONCLUSIONS: Findings support a role for hypothalamic gliosis in the progression of insulin resistance in obesity and thus T2D pathogenesis in humans.

Greater radiologic evidence of hypothalamic gliosis predicts adiposity gain in children at risk for obesity.

OBJECTIVE: This study investigated, in a large pediatric population, whether magnetic resonance imaging (MRI) evidence of mediobasal hypothalamic (MBH) gliosis is associated with baseline or change over 1 year in body adiposity. METHODS: Cross-sectional and prospective cohort analyses were conducted within the Adolescent Brain Cognitive Development Study. Study 1 included 169 children with usable baseline T2-weighted MRI images and anthropometrics from baseline and 1-year follow-up study visits. Signal ratios compared T2 signal intensity in MBH and two reference regions (amygdala [AMY] and putamen) as a measure of MBH gliosis. Study 2 included a distinct group of 238 children with overweight or obesity to confirm initial findings in an independent sample. RESULTS: In Study 1, MBH/AMY signal ratio was positively associated with BMI z score (ß = 4.27, p < 0.001). A significant interaction for the association of MBH/AMY signal ratio with change in BMI z score suggested that relationships differed by baseline weight status. Study 2 found that higher MBH/AMY signal ratios associated with an increase in BMI z score for children with overweight (ß = 0.58, p = 0.01), but not those with obesity (ß = 0.02, p = 0.91). CONCLUSIONS: Greater evidence of hypothalamic gliosis by MRI is associated with baseline BMI z score and predicts adiposity gain in young children at risk of obesity.

Pilot multi-site and reproducibility study of hypothalamic gliosis in children.

OBJECTIVE: Quantitative magnetic resonance imaging (MRI) evidence of mediobasal hypothalamic (MBH) gliosis positively correlates with body mass index (BMI) in adults. This has neither been well explored in children nor have other brain regions involved in appetitive processing been tested for evidence of gliosis. METHODS: Multi-site cross-sectional study in children to test for differences in quantitative T2 signal (measure of gliosis) by region and to assess relationships with age and BMI. Participants underwent brain MRI using the same equipment and protocol to quantify T2 relaxation time in six bilateral regions of interest (ROIs): putamen, caudate, ventral striatum, amygdala, hippocampus and MBH, and three control regions: white matter, motor cortex and dorsal hypothalamus. RESULTS: Thirty-one participants (61% female) were included in a combined sample from the University of Washington (N = 9) and John Hopkins University (N = 22). Mean age was 14 ± 3 years, and BMI z-score was 0.7 ± 1.1 (26% with obesity). No study site-related differences were seen in T2 relaxation time across all nine regions (chi2 (8): 9.46, P = .30). Regional differences in T2 relaxation time were present (P < .001). MBH presented longer T2 relaxation time, suggestive of gliosis, when compared to all regions (P < .001), including an intra-hypothalamic control. Physiological age-related declines in T2 relaxation times were found in grey matter ROIs, but not in the MBH (r = -0.14, P = .46). MBH was the only region with a positive correlation between T2 relaxation time and BMI z-score (r = 0.38, P = .03). CONCLUSIONS: In a multi-site study, pilot data suggest that quantitative MRI detected normal maturation-related brain variation as well as evidence that MBH gliosis is associated with increased adiposity in children.

Reassessing relationships between appetite and adiposity in people at risk of obesity: A twin study using fMRI.

BACKGROUND: Neuroimaging studies suggest that appetitive drive is enhanced in obesity. OBJECTIVE: To test if appetitive drive varies in direct proportion to the level of body adiposity after accounting for genetic factors that contribute to both brain response and obesity risk. SUBJECTS/METHODS: Participants were adult monozygotic (n = 54) and dizygotic (n = 30) twins with at least one member of the pair with obesity. Body composition was assessed by dual-energy X-ray absorptiometry. Hormonal and appetite measures were obtained in response to a standardized meal that provided 20% of estimated daily caloric needs and to an ad libitum buffet meal. Pre- and post-meal functional magnetic resonance imaging (fMRI) assessed brain response to visual food cues in a set of a priori appetite-regulating regions. Exploratory voxelwise analyses outside a priori regions were performed with correction for multiple comparisons. RESULTS: In a group of 84 adults, the majority with obesity (75%), body fat mass was not associated with hormonal responses to a meal (glucose, insulin, glucagon-like peptide-1 and ghrelin, all P>0.40), subjective feelings of hunger (ß=-0.01 mm [95% CI -0.35, 0.34] P = 0.97) and fullness (ß=0.15 mm [-0.15, 0.44] P = 0.33), or buffet meal intake in relation to estimated daily caloric needs (ß=0.28% [-0.05, 0.60] P = 0.10). Body fat mass was also not associated with brain response to high-calorie food cues in appetite-regulating regions (Pre-meal ß=-0.12 [-0.32, 0.09] P = 0.26; Post-meal ß=0.18 [-0.02, 0.37] P = 0.09; Change by a meal ß=0.29 [-0.02, 0.61] P = 0.07). Conversely, lower fat mass was associated with being weight reduced (ß=-0.05% [-0.07, -0.03] P<0.001) and greater pre-meal activation to high-calorie food cues in the dorsolateral prefrontal cortex (Z = 3.63 P = 0.017). CONCLUSIONS: In a large study of adult twins, the majority with overweight or obesity, the level of adiposity was not associated with excess appetitive drive as assessed by behavioral, hormonal, or fMRI measures.

Glucose parameters are altered in mouse offspring produced by assisted reproductive technologies and somatic cell nuclear transfer.

Fortunately, the majority of children conceived through assisted reproductive technologies (ARTs) appear healthy; however, metabolic abnormalities, including elevated glucose and increased and altered adipose tissue deposition, have been reported in adolescents. To parse out factors that may be responsible, we investigated the effects of two different ARTs--in vitro fertilization (IVF) and intracytoplasmic sperm injection (ICSI)--as well as somatic cell nuclear transfer (SCNT) on glucose clearance, body weight, and body composition of young adult mice. Female and male mice generated through ART weighed more than control (naturally conceived [STOCK]) mice at birth. No differences in body weight were observed in males up to 8 wk of age. ART females took longer than control mice to clear a glucose bolus, with glucose clearance most impaired in SCNT females. IVF females secreted more insulin and had a higher insulin peak 15 min after glucose injection compared with all other groups. Male mice exhibited no differences in glucose clearance, but IVF males required more insulin to do so. SCNT females weighed more than IVF, ICSI, and STOCK females, and they had higher fat content than ICSI females and higher leptin levels than all other groups. These results show that glucose parameters are altered in young adult mice conceived through techniques associated with ART before onset of obesity and may be responsible for its development later in life. The present study suggests that more investigation regarding the long-term effects of manipulations associated with ART is warranted.

Meal patterns and hypothalamic NPY expression during chronic social stress and recovery.

In the present study, we examined meal patterns during and after exposure to the visible burrow system (VBS), a rodent model of chronic social stress, to determine how the microstructure of food intake relates to the metabolic consequences of social subordination. Male Long-Evans rats were housed in mixed-sex VBS colonies (4 male, 2 female) for 2 wk, during which time a dominance hierarchy formed [1 dominant male (DOM) and 3 subordinate males (SUB)], and then male rats were individually housed for a 3-wk recovery period. Controls were individually housed with females during the 2-wk VBS period and had no changes in ingestive behavior compared with a habituation period. During the hierarchy-formation phase of VBS housing, DOM and SUB had a reduced meal frequency, whereas SUB also had a reduced meal size. However, during the hierarchy-maintenance phase of VBS housing, DOM meal patterns did not differ from controls, whereas SUB continued to display a reduced food intake via less frequent meals. During recovery, DOM had comparable meal patterns to controls, whereas SUB had an increased meal size. Hypothalamic neuropeptide Y (NPY) mRNA levels were not different between these groups during the experimental period. Together, the results suggest that exposure to chronic social stress alters ingestive behavior both acutely and in the long term, which may influence the metabolic changes that accompany bouts of stress and recovery; however, these differences in meal patterns do not appear to be mediated by hypothalamic NPY.