A peptide triple agonist of GLP-1, neuropeptide Y1, and neuropeptide Y2 receptors promotes glycemic control and weight loss.

Mechanisms underlying long-term sustained weight loss and glycemic normalization after obesity surgery include changes in gut hormone levels, including glucagon-like peptide 1 (GLP-1) and peptide YY (PYY). We demonstrate that two peptide biased agonists (GEP44 and GEP12) of the GLP-1, neuropeptide Y1, and neuropeptide Y2 receptors (GLP-1R, Y1-R, and Y2-R, respectively) elicit Y1-R antagonist-controlled, GLP-1R-dependent stimulation of insulin secretion in both rat and human pancreatic islets, thus revealing the counteracting effects of Y1-R and GLP-1R agonism. These agonists also promote insulin-independent Y1-R-mediated glucose uptake in muscle tissue ex vivo and more profound reductions in food intake and body weight than liraglutide when administered to diet-induced obese rats. Our findings support a role for Y1-R signaling in glucoregulation and highlight the therapeutic potential of simultaneous receptor targeting to achieve long-term benefits for millions of patients.

Energy balance in hypothalamic obesity in response to treatment with a once-weekly GLP-1 receptor agonist.

BACKGROUND/OBJECTIVES: Hypothalamic obesity (HO) frequently occurs following suprasellar tumors from a combination of decreased energy expenditure and increased energy intake. Glucagon-like peptide-1 receptor agonist (GLP1RA) therapy is associated with increased satiety and energy expenditure. We hypothesized GLP1RA therapy in patients with HO would cause both lower energy intake and increased energy expenditure. SUBJECTS/METHODS: Forty-two patients aged 10-26 years (median 16 years) with HO with suprasellar tumors were randomized to GLP1RA (exenatide extended release once-weekly, ExQW, n = 23) or placebo (n = 19). Thirty seven (81%) patients completed the 36-week double-blind placebo-controlled trial. Total energy expenditure (TEE) was measured with doubly labeled water, physical activity was assessed with actigraphy, and intake was estimated with ad libitum buffet meal. Results are presented as adjusted mean between-group difference. RESULTS: As compared with treatment with placebo, treatment with ExQW was associated with decreased energy intake during a buffet meal (-1800 kJ (-430 kcal), 95% CI -3 184 to -418 kJ, p = 0.02). There were no significant differences in physical activity between groups. ExQW (vs. placebo) treatment was associated with a decrease in TEE (-695 kJ/day (-166 kcal/day), 95% CI -1 130 to -264 kJ/day, p < 0.01, adjusted for baseline TEE). The treatment effect was still significant after further adjustment for change in body composition (-372 kJ/day (-89 kcal/day), 95% CI -699 to -42 kJ/day, p = 0.04) or change in leptin (-695 kJ/day (-166 kcal/day), 95% CI -1 130 to -264 kJ/day, p < 0.01). This decrease in TEE occurred despite an increase in lean mass and fat mass (1.7 vs. 1.3 kg lean mass, p = 0.88 and 1.5 vs. 4.6 kg fat mass, p = 0.04, ExQW vs. placebo). CONCLUSIONS: Treatment with a GLP1RA was associated with a decrease in food intake but also a decrease in TEE that was disproportionate to change in body composition.

A phase 3 randomized clinical trial using a once-weekly glucagon-like peptide-1 receptor agonist in adolescents and young adults with hypothalamic obesity.

AIM: To evaluate the efficacy, safety and tolerability of a glucagon-like peptide-1 receptor agonist (GLP-1 RA) in patients with hypothalamic obesity (HO). MATERIALS AND METHODS: A two-arm, randomized, multicentre, double-blind, placebo-controlled trial was conducted in 10- to 25-year-olds with hypothalamic injury following intracranial tumour and HO. Participants were randomized to once-weekly subcutaneous injections of a GLP-1 RA exenatide 2 mg (ExQW) or placebo for 36 weeks. The primary efficacy endpoint was 36-week % change in body mass index (BMI). Secondary outcomes included change in body composition (by dual energy x-ray absorptiometry). RESULTS: Forty-two participants were randomized to ExQW (n = 23) or placebo (n = 19). Participants were 5 ± 2 years (mean ± SD) postdiagnosis and development of HO (BMI 37.3 ± 7.1 kg/m2 ). In intention-to-treat analysis, the effect of 36-week ExQW vs. placebo on % Δ BMI was not significant (estimated treatment difference -1.7 ± 1.8%, 95% CI -4.1 to 0.6%, P = .40); however, total body fat mass was reduced (estimated treatment difference -3.1 ± 1.4 kg, 95% CI -5.7 to -0.4 kg, P = .02). There was a significant reduction in waist circumference (estimated effect of treatment -3.5 [95% CI -5.5 to -1.6] cm, P = .004). All patients treated with placebo increased % of adipose tissue, while 50% treated with ExQW had reductions (P < .001). Mean HbA1c, glucose tolerance and serum lipids did not change significantly with therapy. ExQW was well tolerated. The most frequent adverse events were transient gastrointestinal disturbances (ExQW vs. placebo: nausea 6/23 vs. 3/18, vomiting 4/23 vs. 4/18 and diarrhoea 7/23 vs. 3/18). CONCLUSIONS: GLP-1 RAs are a promising and safe treatment to improve or stabilize HO in children and young adults.

Changes in Satiety Hormones in Response to Leptin Treatment in a Patient with Leptin Deficiency.

BACKGROUND: We tested whether leptin treatment affects secretion of satiety-related gut peptides and brain-derived neurotrophic factor (BDNF), which is a regulator of energy homeostasis downstream of hypothalamic leptin signaling. METHODS: We report the case of a morbidly obese 14.7-year-old girl with a novel previously reported homozygous leptin gene mutation, in whom hormone secretion was evaluated in 30-min intervals for 10 h (07.30-17.30) to assess BDNF, insulin, glucagon-like peptide-1 (GLP-1), ghrelin, and peptide YY (PYY) secretion before as well as 11 and 46 weeks after start of metreleptin treatment. RESULTS: Leptin substitution resulted in strong reductions of body fat and calorie intake. Insulin secretion increased by 58.9% after 11 weeks, but was reduced by -44.8% after 46 weeks compared to baseline. Similarly, GLP-1 increased after 11 weeks (+15.2%) and decreased after 46 weeks. PYY increased consistently (+5%/ +13.2%, after 11/46 weeks). Ghrelin decreased after 46 weeks (-11%). BDNF secretion was not affected by leptin treatment. CONCLUSION: The strong increase in insulin and GLP-1 secretion after 11 weeks of metreleptin treatment cannot be explained by reduced adiposity and might contribute to improved central satiety. Observed changes of PYY can lead to increased satiety as well. However, leptin replacement does not seem to affect circulating BDNF levels.

Betatrophin: no relation to glucose metabolism or weight status in obese children before and after lifestyle intervention.

OBJECTIVE: The influences of obesity, glucose metabolism, gender, and puberty on betatrophin levels and the longitudinal relationships between weight loss, metabolic changes and betatrophin have not yet been studied in childhood. METHODS: Cross-sectional and longitudinal analysis of weight status (standard deviation score-body mass index (SDS-BMI)), homeostasis model assessment insulin resistance (HOMA-IR), gender, and pubertal stage were evaluated in 69 obese children (51% female, age 11.9 ± 2.0 years) participating in lifestyle intervention over a 1-year period. An oral glucose tolerance test was performed in 53 of the 69 children. Twenty normal weight children (50% female, age 12.3 ± 3.0 years) served as controls. RESULTS: Circulating betatrophin did not differ significantly between obese and lean children (1.99 ± 0.90 vs 2.35 ± 0.28, mean ± SD, P = .155). At baseline, betatrophin did not differ in obese patients with vs without glucose intolerance (1.89 ± 0.96 vs 2.031 ± 0.91 ng/mL; P = .591) and obese with (delta SDS-BMI >0.4) vs without successful obesity intervention (1.89 ± 0.94 vs. 2.07 ± 0.87 ng/mL; P = 0.396). In multiple linear regression analyses, pubertal stage was associated with betatrophin (b: 0.48, P = .027), while gender, age, BMI, blood pressure, fasting glucose, HOMA-IR, triglycerides, LDL- and HDL-cholesterol were not related to betatrophin at baseline. At the end of the 1-year intervention, changes of betatrophin were not significantly associated with any parameter after controlling for multiple covariates including age and changes of pubertal stages. CONCLUSIONS: Our data do not support a relationship between betatrophin and weight status or glucose tolerance, insulin resistance, and lipid metabolism in children.

Robust Reductions of Excess Weight and Hyperphagia by Beloranib in Rat Models of Genetic and Hypothalamic Obesity.

Hypothalamic lesions or deficient melanocortin (MC) signaling via MC4 receptor (MC4r) mutations often lead to hyperphagia and severe treatment-resistant obesity. We tested the methionine aminopeptidase 2-inhibitor beloranib (ZGN-440) in 2 male rat models of obesity, one modeling hypothalamic obesity with a combined medial hypothalamic lesion (CMHL) and the other modeling a monogenic form of obesity with MC4r mutations (MC4r knockout [MC4rKO]). In CMHL rats (age 3 months), postsurgery excess weight gain was significantly inhibited (ZGN-440, 0.2 ± 0.7 g/d; vehicle, 3.8 ± 0.6 g/d; P < 0.001) during 12 days of ZGN-440 treatment (0.1 mg/kg daily subcutaneously) together with a 30% reduction of daily food intake vs vehicle injection. In addition, ZGN-440 treatment improved glucose tolerance and reduced plasma insulin, and circulating levels of α-melanocyte stimulating hormone were increased. Serum lipid levels did not differ significantly in ZGN-440-treated vs vehicle-treated rats. Similar results were found in MC4rKO rats: ZGN-440 treatment (14-21 d) was associated with significant reductions of body weight gain (MC4rKO, -1.7 ± 0.6 vs 2.8 ± 0.4 g/d; lean wild-type controls, -0.7 ± 0.2 vs 1.7 ± 0.7 g/d; ZGN-440 vs vehicle, respectively), reduction of food intake (MC4rKO, -28%; lean controls, -7.5%), and insulin resistance, whereas circulating levels of interleukin-1ß did not change. In both obesity models, body temperature and locomotor activity were not affected by ZGN-440 treatment. In conclusion, the robust reduction of body weight in response to ZGN-440 observed in rats with severe obesity is related to a strong reduction of food intake that is likely related to changes in the central regulation of feeding.

Activation of nuclear factor kappa B pathway and reduction of hypothalamic oxytocin following hypothalamic lesions.

BACKGROUND: Hypothalamic obesity (HO) occurs in patients with tumors and lesions in the medial hypothalamic region. In this study, a hyperphagic rat model of combined medial hypothalamic lesions (CMHL) was used to test which specific inflammatory molecules are involved. METHODS: In order to target specific homeostatic medial hypothalamic nuclei (arcuate, ventromedial, and dorsomedial nuclei), male Sprague-Dawley rats (age of 8 weeks, ~250 g body weight) received four electrolytic lesions or sham surgery. Post-surgery food intake and weight changes were tracked and hypothalamic gene expression for inflammatory molecules as well as anorexigenic peptide oxytocin 7 days and 7 months post-surgery were tested. RESULTS: Seven days post-surgery, average food intake increased by 23%, and body weight gain had increased by 68%. Toll-like 4 receptor/nuclear factor-κB (TLR4/NF-κB)-pathway was specifically activated in the mediobasal hypothalamus (MBH), resulting in 3-fold higher tumor necrosis factor (TNF)-α, 10-fold higher interleukin (IL) 1-ß mRNA levels, and higher expression of suppression of cytokine signaling (SOCS) 3, while oxytocin mRNA levels were significantly reduced in CMHL rats versus sham surgery rats 7 days post-surgery. At 7 months, inflammation was less stimulated in MBH of CMHL rats compared to 7 days post-surgery and SOCS 3 as well as oxytocin mRNA levels were comparable between the two groups. CONCLUSION: Medial hypothalamic lesions are associated with strong post-surgery hyperphagia and activation of TLR4/NF-κB-pathway as well as reduced expression of oxytocin in the hypothalamus.

Pediatric Central Diabetes Insipidus: Brain Malformations Are Common and Few Patients Have Idiopathic Disease.

CONTEXT: Pediatric cohorts of central diabetes insipidus (CDI) have shown varying prevalences for the different causes of CDI, including idiopathic. OBJECTIVE: The objective of the study was to determine the causes of CDI at a pediatric tertiary care center and to characterize their clinical outcomes. DESIGN AND SETTING: All patients with CDI at Seattle Children's Hospital were identified and retrospectively analyzed. PATIENTS: From 2000 to 2013, 147 patients with CDI were encountered (mean age 7 y at diagnosis, mean follow-up 6.2 y). OUTCOME MEASURES: The different causes of CDI were grouped, and age of diagnosis, anterior pituitary hormone deficiencies (APHDs), and presence of the posterior pituitary bright spot (PPBS) were analyzed. Patients with idiopathic CDI had infundibular thickening measured using a systematic method. RESULTS: Brain malformations caused 24% of CDI cases, and 12.2% were idiopathic. Four of 22 patients with initially idiopathic CDI were diagnosed with an underlying condition, none occurring later than 2.5 years from diagnosis. APHDs were as common in the brain malformation group as they were in the tumor/infiltrative group (72% vs 85%; P = .09). The PPBS was present in at least 13% of patients and in 19% of those with brain malformations. Patients with idiopathic CDI and stalk thickening on the initial magnetic resonance imaging were more likely to have an underlying diagnosis (40% vs 0%; P = .03). CONCLUSIONS: Brain malformations were a more common cause of pediatric CDI than previously reported. These patients have a high rate of APHDs, and many have persistence of the PPBS. Idiopathic CDI is an uncommon diagnosis, and none of our patients were diagnosed with Langerhans cell histiocytosis or germinoma for more than 3 years from CDI diagnosis. Providers can consider less frequent magnetic resonance imaging after this time point. A systematic method of infundibular measurement on the initial magnetic resonance imaging may predict an underlying germinoma or Langerhans cell histiocytosis.

Semiquantitative analysis of hypothalamic damage on MRI predicts risk for hypothalamic obesity.

OBJECTIVE: Excessive weight gain frequently occurs in patients with hypothalamic tumors and lesions leading to hypothalamic obesity (HO). METHODS: Digital brain magnetic resonance imaging (MRI) and clinical outcomes were studied retrospectively in a single center, including 45 children with postoperative lesions in the sellar region (41 craniopharyngiomas, 4 with Rathke's cleft cysts), ∼5 years post-surgery, mean age 13.9 years. Four standard sections covering hypothalamic areas critical to energy homeostasis were used to assess lesions and calculate a hypothalamic lesion score (HLS); the association with HO was examined. RESULTS: Compared to subjects who did not develop HO (n = 23), subjects with HO (n = 22) showed more frequently lesions affecting the third ventricular floor, mammillary bodies, and anterior, medial (all P < 0.05), and most importantly posterior hypothalamus (P < 0.01). The HLS correlated significantly with BMI z-score changes 12 and 30 months post-surgery, even after adjusting for potential confounders of gender, age at surgery, surgery date, surgery BMI z-score, hydrocephalus, and residual hypothalamic tumor (r = 0.34, P = 0.03; r = 0.40, P = 0.02, respectively). Diabetes insipidus was found to be an endocrine marker for HO risk. CONCLUSIONS: The extent of damage following surgery in the sellar region can be assessed by MRI using a novel scoring system for early HO risk assessment.

Reduced adiponectin signaling due to weight gain results in nonalcoholic steatohepatitis through impaired mitochondrial biogenesis.

UNLABELLED: Obesity and adiponectin depletion have been associated with the occurrence of nonalcoholic fatty liver disease (NAFLD). The goal of this study was to identify the relationship between weight gain, adiponectin signaling, and development of nonalcoholic steatohepatitis (NASH) in an obese, diabetic mouse model. Leptin-receptor deficient (Lepr(db/db) ) and C57BL/6 mice were administered a diet high in unsaturated fat (HF) (61%) or normal chow for 5 or 10 weeks. Liver histology was evaluated using steatosis, inflammation, and ballooning scores. Serum, adipose tissue, and liver were analyzed for changes in metabolic parameters, messenger RNA (mRNA), and protein levels. Lepr(db/db) HF mice developed marked obesity, hepatic steatosis, and more than 50% progressed to NASH at each timepoint. Serum adiponectin level demonstrated a strong inverse relationship with body mass (r = -0.82; P < 0.0001) and adiponectin level was an independent predictor of NASH (13.6 µg/mL; P < 0.05; area under the receiver operating curve (AUROC) = 0.84). White adipose tissue of NASH mice was characterized by increased expression of genes linked to oxidative stress, macrophage infiltration, reduced adiponectin, and impaired lipid metabolism. HF lepr (db/db) NASH mice exhibited diminished hepatic adiponectin signaling evidenced by reduced levels of adiponectin receptor-2, inactivation of adenosine monophosphate activated protein kinase (AMPK), and decreased expression of genes involved in mitochondrial biogenesis and ß-oxidation (Cox4, Nrf1, Pgc1α, Pgc1ß and Tfam). In contrast, recombinant adiponectin administration up-regulated the expression of mitochondrial genes in AML-12 hepatocytes, with or without lipid-loading. CONCLUSION: Lepr(db/db) mice fed a diet high in unsaturated fat develop weight gain and NASH through adiponectin depletion, which is associated with adipose tissue inflammation and hepatic mitochondrial dysfunction. We propose that this murine model of NASH may provide novel insights into the mechanism for development of human NASH.

Glucagon-like peptide-1 agonist exendin-4 leads to reduction of weight and caloric intake in a rat model of hypothalamic obesity.

BACKGROUND: Hypothalamic obesity caused by damage of medial hypothalamic nuclei presents a therapeutic challenge. Glucagon-like peptide-1 agonist exenatide (synthetic version of exendin-4 (Ex4)), used for treatment of diabetes, causes weight loss via hindbrain signaling. METHODS: We tested Ex4 in an established rat model of medial hypothalamic lesions. Lesion and control animals were administered either daily intraperitoneal injections of 1 µg·kg(-1) Ex4 or saline for 9 days. RESULTS: In our rat model, a significant difference in percent baseline food intake (lesion -20.8%, control -13.6%; p < 0.001) and percent change in body weight (lesion -4.9%/9 days, control -3.2%/9 days; p < 0.05) was observed during Ex4 treatment compared with saline. CONCLUSION: Ex4 resulted in reduction of food intake and body weight. Follow-up studies are required to further elucidate its effects on energy homeostasis and to establish Ex4 as a potential drug for treatment of hypothalamic obesity.

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.

Studies of different female rat models of hypothalamic obesity.

Hypothalamic obesity (HO) is a major and unsolved problem in patients with medial hypothalamic lesions and is associated with hyperinsulinemia and hyperleptinemia. The purpose of this study was to create a rodent model that mimics metabolic changes in HO for use in therapeutic testing. Female Sprague-Dawley rats were used to test the individual and combined effects of two types of medial hypothalamic lesions: arcuate nucleus (ARC) lesions by injection of monosodium glutamate at neonatal age, and ventromedial nucleus (VMN) lesions by passing an anodal current through an electrode placed in the VMN at age 80 days. Adiposity in ARC-lesioned animals was associated with decreased food intake and stunted growth, while VMN lesions were associated with hyperphagia but not reduced growth. The greatest weight gain (weight at age 200 days 712 +/- 65 vs. 451 +/- 19 g in controls), hyperphagia (food intake 10 days following surgery 33 +/- 0.8 vs. 18.5 +/- 0.7 g/day in sham-treated rats), hyperinsulinemia and hyperleptinemia occurred in rats that received both ARC and VMN lesions. Thus, the combined medial hypothalamic lesions result in an obesity phenotype similar to that of patients that suffer from HO and are consequently more suitable for testing potential therapeutics for this disorder than lesions of single hypothalamic nuclei.

A novel rodent model that mimics the metabolic sequelae of obese craniopharyngioma patients.

Patients with craniopharyngioma (CP), a tumor located in the pituitary and/or hypothalamus, are susceptible to developing obesity and many metabolic complications. The study aim was to create a rodent model that mimics the complex neuroanatomical and metabolic disturbances commonly seen in obese CP patients. We compared the metabolic phenotype of animals with three distinct types of hypothalamic lesions: 1) destruction of the arcuate nucleus (ARC) induced by monosodium glutamate (MSG), 2) electrolytic lesion of the adjacent ventromedial nucleus (VMN) alone, 3) both the VMN and dorsomedial nucleus (DMN), or a 4) combined medial hypothalamic lesion (CMHL) affecting the VMN, DMN, and the ARC. Only the CMHL model exhibited all key features observed in patients with hypothalamic obesity induced by CP. These features included excessive weight gain due to increased adiposity, increased food intake, and pronounced hyperinsulinemia and hyperleptinemia. Similar to characteristics of patients with CP, CMHL animals exhibited reduced plasma levels of alpha-melanocyte stimulating hormone and reduced ambulatory activity compared with weight-matched controls. Therefore, the CMHL model best mimics the complex metabolic abnormalities observed in obese CP patients compared with lesions to other hypothalamic areas and provides a foundation for future pharmacological approaches to treat obesity in children with hypothalamic damage.

Effects of methylphenidate on weight gain and food intake in hypothalamic obesity.

UNLABELLED: For patients with a craniopharyngioma (CP), treatment of hypothalamic obesity (HO) and hyperphagia following resection and/or radiotherapy is extremely difficult and few reports have been published on potential drug therapies. Psychomotor stimulant methylphenidate (MPH) has been reported to inhibit food intake (FI). In this paper, we report reduction of body mass index (BMI) and appetite in an adolescent CP patient suffering from HO. We then tested the ability of MPH to attenuate the FI and body weight (BW) gain in a rat model consistent with the neuroanatomical and metabolic disturbances commonly observed in obese CP patients. Specifically, we used a novel electrolytically generated combined medial hypothalamic lesion (CMHL) affecting the arcuate nucleus, ventromedial hypothalamic nucleus, and dorsomedial hypothalamic nucleus to induce hyperphagia, rapid weight gain, and adiposity. Both CMHL and control animals (n = 7 per group) were administered either methylphenidate HCl (MPH; 20 mg kg(-1) day(-1)) or saline for 4 days in a crossover design experiment 28 weeks post-surgery. A significant decrease in percent baseline FI (CMHL -23%, p = 0.008; control -20%, p = 0.002) and percent change in BW (CMHL -1.97%/4 days, p = 0.011; control -1.75%/4 days, p = 0.003) was observed during MPH treatment as compared to saline. CONCLUSION: This study shows MPH treatment of severely obese CMHL rats resulted in significantly reduced FI and BW loss.