Chimeric peptide EP45 as a dual agonist at GLP-1 and NPY2R receptors

We report the design and target validation of chimeric peptide EP45, a novel 45 amino acid monomeric dual agonist peptide that contains amino acid sequence motifs present within the blood glucose-lowering agent exendin-4 (Ex-4) and the appetite-suppressing agent PYY(3-36). In a new high-throughput FRET assay that provides real-time kinetic information concerning levels of cAMP in living cells, EP45 recapitulates the action of Ex-4 to stimulate cAMP production via the glucagon-like peptide-1 receptor (GLP-1R), while also recapitulating the action of PYY(3-36) to inhibit cAMP production via the neuropeptide Y2 receptor (NPY2R). EP45 fails to activate glucagon or GIP receptors, whereas for cells that co-express NPY2R and adenosine A2B receptors, EP45 acts in an NPY2R-mediated manner to suppress stimulatory effects of adenosine on cAMP production. Collectively, such findings are remarkable in that they suggest a new strategy in which the co-existing metabolic disorders of type 2 diabetes and obesity will be treatable using a single peptide such as EP45 that lowers levels of blood glucose by virtue of its GLP-1R-mediated effect, while simultaneously suppressing appetite by virtue of its NPY2R-mediated effect.

Oxytocin and Naltrexone Successfully Treat Hypothalamic Obesity in a Boy Post-Craniopharyngioma Resection

CONTEXT

Hypothalamic obesity, a treatment-resistant condition common to survivors of craniopharyngioma (CP), is strongly associated with a poor quality of life in this population. Oxytocin (OT), a hypothalamic neuropeptide, has been shown to play a role in the regulation of energy balance and to have anorexigenic effects in animal studies. Naltrexone (NAL), an opiate antagonist, has been shown to deter hedonic eating and to potentiate OT's effects.

DESIGN

In this parent-observed study, we tested the administration of intranasal OT for 10 weeks (phase 1), followed by a combination of intranasal OT and NAL for 38 weeks (phase 2) in a 13-year-old male with confirmed hypothalamic obesity and hyperphagia post-CP resection. Treatment resulted in 1) reduction in body mass index (BMI) z score from 1.77 to 1.49 over 10 weeks during phase 1; 2) reduction in BMI z score from 1.49 to 0.82 over 38 weeks during phase 2; 3) reduced hyperphagia during phases 1 and 2; 4) continued hedonic high-carbohydrate food-seeking in the absence of hunger during phases 1 and 2; and 5) sustained weight reduction during decreased parental monitoring and free access to unlocked food in the home during the last 10 weeks of phase 2.

CONCLUSION

This successful intervention of CP-related hypothalamic obesity and hyperphagia by OT alone and in combination with NAL is promising for conducting future studies of this treatment-recalcitrant form of obesity.

Improving the Care of Youth With Type 1 Diabetes With a Novel Medical-Legal Community Intervention: The Diabetes Community Care Ambassador Program

Purpose The purpose of this study was to examine the feasibility and efficacy of the Diabetes Community Care Ambassador (DCCA) Program, a novel medical-legal community intervention designed to support high-risk youth with type 1 diabetes. Methods Study eligibility criteria: ages 3-19 years, A1C ≥8.5% (≥69 mmol/mol) and/or recent diabetic ketoacidosis hospitalization, type 1 diabetes duration ≥1 year, and English- or Spanish-speaking. Eighty-nine youth and their caregivers participated in the 9- to 12-month intervention, which included diabetes education and support through 3 home visits, 1 to 2 school visits, and phone support from a lay health worker, as well as legal support from a medical-legal partnership attorney. Feasibility was assessed; change in A1C was compared in a linear mixed model. Results Of the 89 DCCA Program participants, 80% completed the program, with the majority of participants rating their DCCA favorably. Sixty-two percent reported ≥1 unmet legal need, of whom 29% accepted legal counsel. Youth enrolled in the DCCA Program demonstrated an improvement in glycemic control as their mean A1C decreased from 9.71% (83 mmol/mol) at the start of the program to 9.40% (79 mmol/mol) at the end of the intervention period ( P = .03). Participants with public health insurance experienced the greatest differential A1C reduction (9.79% to 9.11%, 83 mmol/mol to 76 mmol/mol). Conclusions The DCCA Program represents a promising intervention for improving care of high-risk youth with type 1 diabetes. A significant proportion of caregivers of youth reported having an unmet legal need. Participants remained highly engaged and demonstrated improved glycemic control, particularly youth with public health insurance.

Assessment of disturbed glucose metabolism and surrogate measures of insulin sensitivity in obese children and adolescents

BACKGROUND

With the rising prevalence of obesity and type 2 diabetes (T2D) in obese children, it is becoming imperative to detect disturbed glucose metabolism as early as possible in order to prevent T2D development.

SUBJECTS/METHODS

Cross-sectional study of 92 obese children (median age 11.7 years, 51% female) and 7 lean children (median age 11.4 years, 57% female) who underwent an oral glucose tolerance test (OGTT) in a tertiary pediatric care center. Glucose tolerance was assessed and different indices for β-cell function, insulin sensitivity and insulin secretion were calculated.

RESULTS

Nineteen obese children were identified with prediabetes (PD, 12 impaired glucose tolerance, 4 increased fasting glucose and 3 combined). Compared with the 73 obese children with normal glucose tolerance (nGT), subjects with PD had higher insulin resistance, but lower insulin sensitivity and β-cell function, although their glycated hemoglobin (HbA1c) levels were comparable. The Whole Body Insulin Sensitivity Index (WBISI) and β-cell function by Insulin Secretion-Sensitivity Index-2 (ISSI-2) strongly correlated with the OGTT glucose area under the curve 0-120 min (r = 0.392, p < 0.0002; r = 0.547, p < 0.0001, respectively). When testing the relation between early insulin response during OGTT by insulinogenic index and insulin sensitivity assessed by WBISI, a hyperbolic relationship between insulin secretion and insulin sensitivity was found. The calculated disposition index was lower in subjects with PD vs. nGT (median 459 vs. 792, p = 0.004). We identified the OGTT 30-min/120-min insulin ratio as a simple marker, which is significantly lower in obese children with vs. without PD (median 0.87 vs. 1.29, p = 0.021) and which has a better sensitivity and specificity for detecting PD than HbA1c among obese children.

CONCLUSIONS

Children with identified PD had changes of several markers for β-cell function, insulin sensitivity and resistance before changes in HbA1c occurred. The lower disposition index indicates that these children have already inadequate β-cell compensation for the degree of insulin resistance.

Probiotic strains and mechanistic insights for the treatment of type 2 diabetes

INTRODUCTION

The intestinal microbial composition appears to differ between healthy controls and individuals with Type 2 diabetes (T2D). This observation has led to the hypothesis that perturbations of the intestinal microbiota may contribute to the development of T2D. Manipulations of the intestinal microbiota may therefore provide a novel approach in the prevention and treatment of T2D. Indeed, fecal transplants have shown promising results in both animal models for obesity and T2D and in human clinical trials. To avoid possible complications associated with fecal transplants, probiotics are considered as a viable alternative therapy. An important, however often underappreciated, characteristic of probiotics is that individual strains may have different, even opposing, effects on the host. This strain specificity exists also within the same species. A comprehensive understanding of the underlying mechanisms at the strain level is therefore crucial for the selection of suitable probiotic strains.

PURPOSE

The aim of this review is to discuss the mechanisms employed by specific probiotic strains of the Lactobacillus and the Bifidobacterium genuses, which showed efficacy in the treatment of obesity and T2D. Some probiotic strains employ recurring beneficial effects, including the production of anti-microbial lactic acid, while other strains display highly unique features, such as hydrolysis of tannins.

CONCLUSION

A major obstacle in the evaluation of probiotic strains lays in the great number of strains, differences in detection methodology and measured outcome parameters. The understanding of further research should be directed towards the development of standardized evaluation methods to facilitate the comparison of different studies.

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-1β 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.

Just a Gut Feeling: Central Nervous Effects of Peripheral Gastrointestinal Hormones

Despite greater health education, obesity remains one of the greatest health challenges currently facing the world. The prevalence of obesity among children and adolescents and the rising rates of prediabetes and diabetes are of particular concern. A deep understanding of regulatory pathways and development of new anti-obesity drugs with increased efficacy and safety are of utmost necessity. The 2 major biological players in the regulation of food intake are the gut and the brain as peptides released from the gut in response to meals convey information about the energy needs to brain centers of energy homeostasis. There is evidence that gut hormones not only pass the blood-brain barrier and bind to receptors located in different brain areas relevant for body weight regulation, but some are also expressed in the brain as part of hedonic and homeostatic pathways. Regarding obesity interventions, the only truly effective treatment for obesity is bariatric surgery, the long-term benefits of which may actually involve increased activity of gut hormones including peptide YY3-36 and glucagon-like peptide 1. This review discusses critical gut-hormones involved in the regulation of food intake and energy homeostasis and their effects on peripheral tissues versus central nervous system actions.

α-Melanocyte stimulating hormone promotes muscle glucose uptake via melanocortin 5 receptors

Objective

Central melanocortin pathways are well-established regulators of energy balance. However, scant data exist about the role of systemic melanocortin peptides. We set out to determine if peripheral α-melanocyte stimulating hormone (α-MSH) plays a role in glucose homeostasis and tested the hypothesis that the pituitary is able to sense a physiological increase in circulating glucose and responds by secreting α-MSH.

Methods

We established glucose-stimulated α-MSH secretion using humans, non-human primates, and mouse models. Continuous α-MSH infusions were performed during glucose tolerance tests and hyperinsulinemic-euglycemic clamps to evaluate the systemic effect of α-MSH in glucose regulation. Complementary ex vivo and in vitro techniques were employed to delineate the direct action of α-MSH via the melanocortin 5 receptor (MC5R)–PKA axis in skeletal muscles. Combined treatment of non-selective/selective phosphodiesterase inhibitor and α-MSH was adopted to restore glucose tolerance in obese mice.

Results

Here we demonstrate that pituitary secretion of α-MSH is increased by glucose. Peripheral α-MSH increases temperature in skeletal muscles, acts directly on soleus and gastrocnemius muscles to significantly increase glucose uptake, and enhances whole-body glucose clearance via the activation of muscle MC5R and protein kinase A. These actions are absent in obese mice, accompanied by a blunting of α-MSH-induced cAMP levels in skeletal muscles of obese mice. Both selective and non-selective phosphodiesterase inhibition restores α-MSH induced skeletal muscle glucose uptake and improves glucose disposal in obese mice.

Conclusion

These data describe a novel endocrine circuit that modulates glucose homeostasis by pituitary α-MSH, which increases muscle glucose uptake and thermogenesis through the activation of a MC5R-PKA-pathway, which is disrupted in obesity.

•

Glucose stimulates α-MSH release from the pituitary.

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Systemic α-MSH drives glucose disposal and thermogenesis in skeletal muscles.

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α-MSH acts on MC5R expressed on skeletal muscles and activate cAMP-PKA pathway.

•

The combined treatment of nonselective or selective PDE 4 inhibitor and α-MSH ameliorates glucose intolerance in obese mice.

No differential effect of beverages sweetened with fructose, high-fructose corn syrup, or glucose on systemic or adipose tissue inflammation in normal-weight to obese adults: a randomized controlled trial

BACKGROUND

Sugar-sweetened beverage (SSB) consumption and low-grade chronic inflammation are both independently associated with type 2 diabetes and cardiovascular disease. Fructose, a major component of SSBs, may acutely trigger inflammation, which may be one link between SSB consumption and cardiometabolic disease.

OBJECTIVE

We sought to determine whether beverages sweetened with fructose, high-fructose corn syrup (HFCS), and glucose differentially influence systemic inflammation [fasting plasma C-reactive protein and interleukin-6 (IL-6) as primary endpoints] acutely and before major changes in body weight. Secondary endpoints included adipose tissue inflammation, intestinal permeability, and plasma fetuin-A as potential mechanistic links between fructose intake and low-grade inflammation.

DESIGN

We conducted a randomized, controlled, double-blind, crossover design dietary intervention (the Diet and Systemic Inflammation Study) in 24 normal-weight to obese adults without fructose malabsorption. Participants drank 4 servings/d of fructose-, glucose-, or HFCS-sweetened beverages accounting for 25% of estimated calorie requirements while consuming a standardized diet ad libitum for three 8-d periods.

RESULTS

Subjects consumed 116% of their estimated calorie requirement while drinking the beverages with no difference in total energy intake or body weight between groups as reported previously. Fasting plasma concentrations of C-reactive protein and IL-6 did not differ significantly at the end of the 3 diet periods. We did not detect a consistent differential effect of the diets on measures of adipose tissue inflammation except for adiponectin gene expression in adipose tissue (P = 0.005), which was lowest after the glucose phase. We also did not detect consistent evidence of a differential impact of these sugars on measures of intestinal permeability (lactulose:mannitol test, plasma zonulin, and plasma lipopolysaccharide-binding protein).

CONCLUSION

Excessive amounts of fructose, HFCS, and glucose from SSBs consumed over 8 d did not differentially affect low-grade chronic systemic inflammation in normal-weight to obese adults. This trial was registered at clinicaltrials.gov as NCT01424306.

Vitamin D Deficiency Is Associated With Increased Risk of Non-alcoholic Steatohepatitis in Adults With Non-alcoholic Fatty Liver Disease: Possible Role for MAPK and NF-κB?

OBJECTIVES

The objective of this study was to determine the relationship of serum vitamin D deficiency (VDD) to histologic features of non-alcoholic fatty liver disease (NAFLD), and associated demographic, clinical, laboratory, and transcriptomic data in the well-characterized Non-alcoholic Steatohepatitis Clinical Research Network (NASH CRN) cohort.

METHODS

Serum vitamin D 25(OH)D (VD) was quantified by liquid chromatography-tandem mass spectrometry in 190 adults (>18 years) with biopsy-proven NAFLD. Subjects were categorized according to their level of VD as either sufficient (>30 ng/ml), insufficient (≥20≤30 ng/ml), or deficient (VDD; <20 ng/ml). Multivariable logistic regression was used to investigate the association of VDD and the presence of definite NASH and individual histological features of NAFLD after adjusting for age, sex, race, body mass index, alanine aminotransferase, and diabetes status. Hepatic transcriptomic data was compared between VDD and non-VDD subjects.

RESULTS

VDD was present in 55% of subjects and was independently associated with definitive NASH (odds ratio (OR) 3.15, 95% confidence interval (CI), 1.62-6.15, P=0.001), increased lobular inflammation (OR=1.98, 95% CI, 1.08-3.61, P=0.026), more ballooning (OR=2.38, 95% CI, 1.32-4.30, P=0.004), and the presence of fibrosis (OR=2.32, 95% CI, 1.13-4.77, P=0.022). There was a significant inverse relationship between lower levels of serum resistin and increased VD level category (P=0.013). The KRT10, SEMA3B, SNORD3C, ARSD, and IGKV4-1 genes were differentially expressed (false discovery rate <0.05) between VDD and non-VDD subjects. Gene ontology and pathway analysis suggest activation of the mitogen-activated protein kinase and nuclear factor-κB pathways in VDD NAFLD subjects.

CONCLUSIONS

VDD is prevalent among US adult NAFLD patients and is independently associated with a definitive diagnosis of NASH and increased histological severity. Novel associations in proinflammatory pathways were identified, which suggest the mechanism for VDD in the pathogenesis of NASH and support dietary and/or lifestyle modifications to increase vitamin D levels in these patients.

Solution Structure and Constrained Molecular Dynamics Study of Vitamin B12 Conjugates of the Anorectic Peptide PYY(3-36)

Vitamin B12 -peptide conjugates have considerable therapeutic potential through improved pharmacokinetic and/or pharmacodynamic properties imparted on the peptide upon covalent attachment to vitamin B12 (B12 ). There remains a lack of structural studies investigating the effects of B12 conjugation on peptide secondary structure. Determining the solution structure of a B12 -peptide conjugate or conjugates and measuring functions of the conjugate(s) at the target peptide receptor may offer considerable insight concerning the future design of fully optimized conjugates. This methodology is especially useful in tandem with constrained molecular dynamics (MD) studies, such that predictions may be made about conjugates not yet synthesized. Focusing on two B12 conjugates of the anorectic peptide PYY(3-36), one of which was previously demonstrated to have improved food intake reduction compared with PYY(3-36), we performed NMR structural analyses and used the information to conduct MD simulations. The study provides rare structural insight into vitamin B12 conjugates and validates the fact that B12 can be conjugated to a peptide without markedly affecting peptide secondary structure.

Fibroblast growth factor 21 (FGF-21) in obese children: no relationship to growth, IGF-1, and IGFBP-3

BACKGROUND

Fibroblast growth factor 21 (FGF-21) is a hepatic protein that plays a critical role in liver, adipose tissue, and bone metabolism. Animal models reported an increase of FGF-21 and associated growth disturbances in undernutrition. Therefore, we studied the impact of weight loss in obese children on growth, FGF-21, and insulin-like factor 1 (IGF-1) concentrations.

METHODS

We analyzed height, serum concentrations of FGF-21, IGF-1, IGFBP-3, leptin, and insulin at baseline and 1 year later in 30 obese children with substantial weight loss (reduction >0.5 BMI-SDS) and in 30 obese children of similar age, gender, and pubertal stage with stable BMI-SDS. All children participated in a 1-year lifestyle intervention. Height and IGF-1 was transformed to standard deviation score (SDS). Multiple linear regression analyses adjusted for age, gender, and pubertal stage were performed.

RESULTS

At baseline, height-SDS was significantly related to IGF-1-SDS (β-coefficient 0.68 95% confidence interval (95% CI)±0.49; p=0.008) and leptin (β-coefficient 0.042 95% CI±0.030; p=0.008), but not to FGF-21 or insulin. FGF-21 was not significantly associated with IGF-1 or IGFBP-3. In longitudinal analysis, changes of FGF-21 were not significantly related to changes of height, IGF-1-SDS or IGFBP-3. However, in the subgroup of 30 children with substantial BMI-SDS reduction, FGF-21, leptin, insulin, and HOMA decreased significantly.

CONCLUSION

As there was no significant association between FGF-21 and growth or IGF-1 both in cross-sectional and longitudinal analyses, these findings do not support the hypothesis that FGF-21 is involved in growth of obese children. Further studies are necessary to understand the multiple alterations in the growth hormone (GH) axis in obese children.

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-β 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.

Consequences of Early Life Programing by Genetic and Environmental Influences: A Synthesis Regarding Pubertal Timing

Sexual maturation is closely tied to growth and body weight gain, suggesting that regulative metabolic pathways are shared between somatic and pubertal development. The pre- and postnatal environment affects both growth and pubertal development, indicating that common pathways are affected by the environment. Intrauterine and early infantile developmental phases are characterized by high plasticity and thereby susceptibility to factors that affect metabolic function as well as related reproductive function throughout life. In children born small for gestational age, poor nutritional conditions during gestation can modify metabolic systems to adapt to expectations of chronic undernutrition. These children are potentially poorly equipped to cope with energy-dense diets and are possibly programmed to store as much energy as possible, causing rapid weight gain with the risk for adult disease and premature onset of puberty. Environmental factors can cause modifications to the genome, so-called epigenetic changes, to affect gene expression and subsequently modify phenotypic expression of genomic information. Epigenetic modifications, which occur in children born small for gestational age, are thought to underlie part of the metabolic programming that subsequently effects both somatic and pubertal development.

No difference in ad libitum energy intake in healthy men and women consuming beverages sweetened with fructose, glucose, or high-fructose corn syrup: a randomized trial

BACKGROUND

Increased energy intake is consistently observed in individuals consuming sugar-sweetened beverages (SSBs), likely mainly because of an inadequate satiety response to liquid calories. However, SSBs have a high content of fructose, the consumption of which acutely fails to trigger responses in key signals involved in energy homeostasis. It is unclear whether the fructose content of SSBs contributes to the increased energy intake in individuals drinking SSBs.

OBJECTIVE

We investigated whether the relative amounts of fructose and glucose in SSBs modifies ad libitum energy intake over 8 d in healthy adults without fructose malabsorption.

DESIGN

We conducted 2 randomized, controlled, double-blind crossover studies to compare the effects of consuming 4 servings/d of a fructose-, glucose-, or aspartame-sweetened beverage (study A; n = 9) or a fructose-, glucose-, or high-fructose corn syrup (HFCS)-sweetened beverage (study B; n = 24) for 8 d on overall energy intake. SSBs were provided at 25% of estimated energy requirement, or an equivalent volume of the aspartame-sweetened beverage, and consumption was mandatory. All solid foods were provided at 125% of estimated energy requirements and were consumed ad libitum.

RESULTS

In study A, ad libitum energy intake was 120% ± 10%, 117% ± 12%, and 102% ± 15% of estimated energy requirements when subjects consumed the fructose-, glucose-, and aspartame-sweetened beverages. Energy intake was significantly higher in the fructose and glucose phases than in the aspartame phase (P < 0.003 for each), with no difference between the fructose and glucose phases (P = 0.462). In study B, total energy intake during the fructose, HFCS, and glucose phases was 116% ± 14%, 116% ± 16%, and 116% ± 16% of the subject's estimated total energy requirements (P = 0.880).

CONCLUSIONS

In healthy adults, total 8-d ad libitum energy intake was increased in individuals consuming SSBs compared with aspartame-sweetened beverages. The energy overconsumption observed in individuals consuming SSBs occurred independently of the relative amounts of fructose and glucose in the beverages. These trials were registered at clinicaltrials.gov as NCT00475475 and NCT01424306.

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.

The gut sensor as regulator of body weight

The gastrointestinal (GI) tract comprises a large endocrine organ that regulates not only nutrient sensing and metabolising but also satiety and energy homeostasis. More than 20 hormones secreted from the stomach, intestine, and pancreas as well as signaling mediators of the gut microbiome are involved in this process. A better understanding of how related pathways affect body weight and food intake will help us to find new strategies and drugs to treat obesity. For example, weight loss secondary to lifestyle intervention is often accompanied by unfavorable changes in multiple GI hormones, which may cause difficulties in maintaining a lower body weight status. Conversely, bariatric surgery favorably changes the hormone profile to support improved satiety and metabolic function. This partially explains stronger sustained body weight reduction resulting in better long-term results of improved metabolic functions. This review focuses on GI hormones and signaling mediators of the microbiome involved in satiety regulation and energy homeostasis and summarizes their changes following weight loss. Furthermore, the potential role of GI hormones as anti-obesity drugs is discussed.

Irisin and its relation to insulin resistance and puberty in obese children: a longitudinal analysis

CONTEXT

Irisin is a recently identified myokine affecting metabolic and glucose homeostasis. However, the role of irisin in obesity and its metabolic consequences are controversial, and data in children are scarce.

OBJECTIVE

To study the relationships between irisin, insulin resistance, and puberty before and after weight loss in obese children with and without impaired glucose tolerance.

DESIGN

One-year follow-up study in obese children participating in a lifestyle intervention.

SETTING

Primary care.

PATIENTS

Forty obese children and 20 normal-weight children of similar age, gender, and pubertal stage.

INTERVENTION

A 1-year outpatient intervention program based on exercise, behavior, and nutrition therapy.

MAIN OUTCOMES MEASURES

Fasting serum irisin, weight status (body mass index [BMI] SD score), and the following parameters of the metabolic syndrome: insulin resistance index (homeostasis model of assessment), blood pressure, and lipids.

RESULTS

The irisin levels were the highest in obese children with impaired glucose tolerance, followed by obese children with normal glucose tolerance, and levels were lowest in normal-weight children (P < .001). In a multiple linear regression analysis, baseline irisin was significantly associated with pubertal stage, high-density lipoprotein-cholesterol, and homeostasis model of assessment, but not to age, gender, BMI, or any other parameter of the metabolic syndrome. The irisin concentrations were significantly (P = .010) lower in the prepubertal compared to the pubertal children. In longitudinal analyses, changes of irisin were significantly associated with entry into puberty, change of fasting glucose, and 2-hour glucose in an oral glucose tolerance test, but not with change of BMI or any other parameter.

CONCLUSIONS

Irisin levels are related to pubertal stage and insulin resistance but not to weight status in childhood.

Vitamin B12 conjugation of peptide-YY(3-36) decreases food intake compared to native peptide-YY(3-36) upon subcutaneous administration in male rats

Challenges to peptide-based therapies include rapid clearance, ready degradation by hydrolysis/proteolysis, and poor intestinal uptake and/or a need for blood brain barrier transport. This work evaluates the efficacy of conjugation of vitamin B12 (B12) on sc administered peptide tyrosine tyrosine (PYY)(3-36) function. In the current experiments, a B12-PYY(3-36) conjugate was tested against native PYY(3-36), and an inactive conjugate B12-PYYC36 (null control) in vitro and in vivo. In vitro experiments demonstrated similar agonism for the neuropeptide Y2 receptor by the B12-PYY(3-36) conjugate (EC50 26.5 nM) compared with native PYY(3-36) (EC50 16.0 nM), with the null control having an EC50 of 1.8 μM. In vivo experiments were performed in young adult male Sprague Dawley rats (9 wk). Daily treatments were delivered sc in five 1-hour pulses, each pulse delivering 5-10 nmol/kg, by implanted microinfusion pumps. Increases in hindbrain Fos expression were comparable 90 minutes after B12-PYY(3-36) or PYY3-36 injection relative to saline or B12-PYYC36. Food intake was reduced during a 5-day treatment for both B12-PYY(3-36)- (24%, P = .001) and PYY(3-36)-(13%, P = .008) treated groups relative to baseline. In addition, reduction of food intake after the three dark cycle treatment pulses was more consistent with B12-PYY(3-36) treatment (-26%, -29%, -27%) compared with the PYY(3-36) treatment (-3%, -21%, -16%), and B12-PYY(3-36) generated a significantly longer inhibition of food intake vs. PYY(3-36) treatment after the first two pulses (P = .041 and P = .036, respectively). These findings demonstrate a stronger, more consistent, and longer inhibition of food intake after the pulses of B12-PYY(3-36) conjugate compared with the native PYY(3-36).

FTO gene: association to weight regain after lifestyle intervention in overweight children

OBJECTIVE

Polymorphisms in intron 1 of the 'fat mass and obesity-associated' (FTO) gene are associated with weight status. We hypothesized that the risk allele at a polymorphism in intron 1 of FTO is associated with weight regain after end of lifestyle intervention.

METHODS

We longitudinally analyzed the changes of weight status as BMI-SDS in 346 unrelated overweight children (mean age 10.6 ± 2.6 years, 45% male, mean BMI-SDS 2.39 ± 0.49) both at the end of a 1-year lifestyle intervention and 1 year after the end of this intervention. We genotyped the obesity risk SNP rs9939609 at FTO by ARMS-PCR.

RESULTS

The children reduced their BMI-SDS (-0.29 ± 0.33; p < 0.001) during intervention and increased their BMI-SDS between the end of intervention and 1 year later (+0.10 ± 0.41; p < 0.001). The obesity risk allele at FTO SNP rs9939609 was not associated with BMI-SDS reduction during the lifestyle intervention (p = 0.622), but with weight regain 1 year after end of the intervention in multiple linear regression analyses adjusted for age, sex, pubertal stage, and baseline BMI-SDS (Bonferroni corrected p = 0.002).

CONCLUSIONS

The obesity risk allele at a polymorphism in intron 1 of FTO was associated with weight regain 1 year after a 1-year lifestyle intervention.

Relation between vitamin D status and nonalcoholic fatty liver disease in children

OBJECTIVES

In adults, vitamin D deficiency is common in patients with nonalcoholic fatty liver disease (NAFLD) and has been associated with the severity of histology. There are known differences between adult and pediatric NAFLD, with little data regarding the relation between vitamin D and pediatric NAFLD. The aim of the present study was to examine the relation between vitamin D levels and NAFLD in children.

METHODS

Clinical and histological data were used from children ages 2 to 18 years with biopsy-proven NAFLD enrolled in the Nonalcoholic Steatohepatitis Clinical Research Network studies. 25(OH) vitamin D levels were measured from serum. Data examined included demographics, anthropometrics, laboratory markers, and liver histology. Data were analyzed using 3 categories of vitamin D level: deficient (≤ 20 ng/mL), insufficient (21-29 ng/mL), and sufficient (≥ 30 ng/mL).

RESULTS

A total of 102 children were studied. There was a high prevalence (80/102, 78%) of vitamin D deficiency or insufficiency; however, there were no significant associations between vitamin D level and the histological characteristics or severity of NAFLD. Significantly higher levels of triglycerides were found in those with vitamin D deficiency (P = 0.004), but there was no association with other features of the metabolic syndrome.

CONCLUSIONS

There is a high prevalence of vitamin D deficiency and insufficiency in children with biopsy-proven NAFLD; however, no association was found between vitamin D deficiency and the severity of disease on biopsies. This differs from adult NAFLD studies in which vitamin D deficiency correlates with histological severity, suggesting differences in the risk factors for or consequences of pediatric NAFLD.

Obesity management in Prader-Willi syndrome

Prader-Willi Syndrome (PWS) is one of the most common genetic causes of obesity. The phenotype of obesity in PWS is unique and characterized by hyperphagia, earlier meal initiation, delayed meal termination, reduced energy expenditure, abnormal gut hormone profiles, as well as irregular responses to food in areas of the brain associated with satiety and reward. Management of obesity is necessary to avoid major morbidity. The relentless food-seeking behavior associated with PWS such as stealing, hoarding food, eating inedibles, and lying about eating, can cause turmoil both inside and outside of the home. Management is challenging for both patients and caretakers, but at this time there are limited medical therapies available besides dietary restriction and behavior management. However, current research shows promise for discovery of additional treatment options for hyperphagia and obesity management in PWS.

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.