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Introduction Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator that has demonstrated clinical benefits in phase 3 trials. We report results from a real-world study (BRIO) to assess the effectiveness of ivacaftor in people with cystic fibrosis (pwCF) in France. Methods BRIO was an observational study conducted at 35 centers in France. Both pwCF initiating ivacaftor treatment and those already taking ivacaftor were included and prospectively followed for 24 months. The primary objective was to evaluate the effect of ivacaftor on percent predicted forced expiratory volume in 1 s (ppFEV1); secondary objectives were evaluating the effect of ivacaftor on clinical effectiveness, healthcare resource utilization (HCRU), and safety. Results A total of 129 pwCF were enrolled; 58.9% were aged

Continuous glucose monitoring (CGM) metrics and self-reported disease characteristics (severe hypoglycemic events [SHEs], HbA1c) warrant further description in people with T1D using CGM and pumps, including hybrid closed-loop systems (HCLS) . We conducted a one-time online survey of adults with T1D in the T1D Exchange Registry or online communities, where ∼50% of participants contributed up to 1 year of CGM data. Patients were asked about their medical history (SHEs, HbA1c) , while glucose management indicator (GMI) , prolonged hypoglycemic events ( Disclosure L.M.Laffel: Advisory Panel; Medtronic, Roche Diabetes Care, Consultant; Boehringer Ingelheim International GmbH, Dexcom, Inc., Dompé, Insulet Corporation, Janssen Pharmaceuticals, Inc., Lilly Diabetes, Novo Nordisk, Provention Bio, Inc. K.S.M.Chapman: None. D.Finan: None. R.M.Bergenstal: Advisory Panel; Hygieia, Medtronic, Roche Diabetes Care, Zealand Pharma A/S, Consultant; Abbott Diabetes, Ascensia Diabetes Care, Bigfoot Biomedical, Inc., CeQur SA, Dexcom, Inc., Eli Lilly and Company, Novo Nordisk, Onduo LLC, Sanofi, United HealthCare Services, Inc., Research Support; Abbott Diabetes, Dexcom, Inc., Eli Lilly and Company, Insulet Corporation, Medtronic, Novo Nordisk, Sanofi. J.Liu: None. L.Titievsky: Employee; Intercept Pharmaceuticals, Inc., Pfizer Inc., Vertex Pharmaceuticals Incorporated, Stock/Shareholder; Intercept Pharmaceuticals, Inc., Pfizer Inc., Vertex Pharmaceuticals Incorporated. K.Hagan: Employee; Vertex Pharmaceuticals Incorporated. T.Liu: Employee; Takeda Pharmaceutical Company Limited, Vertex Pharmaceuticals Incorporated, Stock/Shareholder; Seattle Genetics, Inc. K.Chandarana: Employee; Vertex Pharmaceuticals Incorporated. J.L.Gaglia: Advisory Panel; Dompé, Regeneron Pharmaceuticals Inc., Consultant; Vertex Pharmaceuticals Incorporated, Research Support; Avotres Inc., Dompé, Janssen Research & Development, LLC, Provention Bio, Inc., Stock/Shareholder; Vertex Pharmaceuticals Incorporated. W.Wolf: None. J.Bispham: Employee; PPD Inc., T1D Exchange.

Trials of continuous glucose monitors (CGMs) and hybrid closed-loop systems (HCLS) demonstrate improvements in glycemia with reductions in hypoglycemia in T1D, but there is limited real-world data on how these technologies impact the prevalence of impaired awareness of hypoglycemia (IAH) , severe hypoglycemic events (SHEs) , and glycemic control. We conducted a one-time online survey of adults with T1D in the T1D Exchange Registry and online communities. Self-reported medical histories (insulin delivery method, HbA1c, IAH, SHEs) and CGM data were collected. 2044 patients (mean age 43 y, mean T1D duration 26 y, 72% female, 95% White) completed the survey. Most reported using CGMs (92%) ; 953 also used HCLS. Mean HbA1c was 6.89%; 41.5% had an HbA1C of ≥7%; 30.7% reported IAH; 19.8% had ≥1 SHE in the prior year; 12.0% had ≥2 SHEs in the prior year; 9.6% had IAH + ≥1 SHE; and 6.6% had IAH + ≥2 SHEs (Table) . Rates of SHEs and IAH + SHEs were lower in CGM users and CGM + HCLS users than in non-CGM users; however, among CGM + HCLS users, 16.6% reported ≥1 SHE, 8.7% ≥2 SHEs, 7.8% IAH + ≥1 SHE, and 4.7% IAH + ≥2 SHEs. Also, 35.6% of CGM + HCLS users had an HbA1C of ≥7%. In a patient cohort with high rates of technology adoption, rates of SHEs and IAH remained high, with a significant proportion of patients not achieving targeted glycemic control, indicating the need for novel T1D treatments. Disclosure J. Pettus: Advisory Panel; Lilly, MannKind Corporation, Novo Nordisk, Sanofi. Consultant; Carmot Therapeutics, Inc., Diasome. L. Titievsky: Employee; Intercept Pharmaceuticals, Inc., Pfizer Inc., Vertex Pharmaceuticals Incorporated. Stock/Shareholder; Intercept Pharmaceuticals, Inc., Pfizer Inc., Vertex Pharmaceuticals Incorporated. K. Hagan: Employee; Vertex Pharmaceuticals Incorporated. T. Liu: Employee; Takeda Pharmaceutical Company Limited, Vertex Pharmaceuticals Incorporated. Stock/Shareholder; Seattle Genetics, Inc. K. Chandarana: Employee; Vertex Pharmaceuticals Incorporated. J.L. Gaglia: Advisory Panel; Dompé, Regeneron Pharmaceuticals Inc. Consultant; Vertex Pharmaceuticals Incorporated. Research Support; Avotres Inc., Dompé, Janssen Research & Development, LLC, Provention Bio, Inc. Stock/Shareholder; Vertex Pharmaceuticals Incorporated. W. Wolf: None. J. Bispham: Employee; PPD Inc., T1D Exchange. K.S.M. Chapman: None. D. Finan: None. J. Sherr: Advisory Panel; Bigfoot Biomedical, Inc., Cecelia Health, Insulet Corporation, Medtronic, Vertex Pharmaceuticals Incorporated. Consultant; Insulet Corporation, Lexicon Pharmaceuticals, Inc. Research Support; Dexcom, Inc., Insulet Corporation, Jaeb Center for Health Research, JDRF, Medtronic, National Institute of Diabetes and Digestive and Kidney Diseases. Speaker's Bureau; Lilly Diabetes.

Rationale: Ivacaftor's clinical effects in the residual function mutations 3849+10kb C →T and D1152H warrant further characterization. Objectives: Evaluate ivacaftor's effect in people with cystic fibrosis aged ≥6 years with 3849+10kb C→T or D1152H residual function mutations; explore the correlation between ivacaftor-induced organoid-based cystic fibrosis transmembrane conductance regulator function measurements and clinical response to ivacaftor. Methods: Participants were randomized (1:1) in this placebo-controlled crossover study; each treatment sequence included two 8-week treatments with an 8-week washout period. The primary endpoint was absolute change in lung clearance index2.5 from baseline through Week 8. Additional endpoints included lung function, patient-reported outcomes, and in vitro intestinal organoid-based measurements of ivacaftor-induced cystic fibrosis transmembrane conductance regulator function. Results: Of 38 participants, 37 completed the study. The primary endpoint was met; the Bayesian posterior probability of improvement in lung clearance index2.5 with ivacaftor vs placebo was >99%. Additional endpoints improved with ivacaftor. Safety findings were consistent with ivacaftor's known safety profile. Dose-dependent swelling was observed in 23/25 viable organoid cultures with ivacaftor treatment. Correlations between ivacaftor-induced organoid swelling and clinical endpoints were negligible to low. Conclusions: In people with cystic fibrosis aged ≥6 years with a 3849+10kb C →T or D1152H mutation, ivacaftor treatment improved clinical endpoints vs placebo; however, there was no correlation between organoid swelling and change in clinical endpoints. The organoid assay may assist in identification of ivacaftor-responsive mutations but in this study did not predict magnitude of clinical benefit for individual people with cystic fibrosis with these two mutations. Clinical trial registered with ClinicalTrials.gov (NCT03068312).

VOCAL was an observational study of the effect of long-term ivacaftor on real-world clinical outcomes and healthcare resource utilization (HCRU) in people with cystic fibrosis (pwCF) in Italy, the Netherlands, and the UK.pwCF aged ≥6 years with non-G551D-CFTR gating mutations were eligible. Prospective data were collected up to 48 months after enrollment; retrospective data were collected to ensure that 12 months of pre-ivacaftor data were available. Endpoints included absolute change from baseline in percent predicted forced expiratory volume in 1 second (ppFEVSeventy-three eligible pwCF were enrolled and received ivacaftor; 65 (89.0%) completed the study (48 [65.8%] completed ≥48 months of ivacaftor). During the first 6 months of ivacaftor, ppFEVThese results demonstrate the positive long-term effectiveness of ivacaftor on clinical outcomes and HCRU in pwCF with non-G551D-CFTR gating mutations in real-world settings.

Introduction Ivacaftor was first approved in 2012 for the treatment of a select population of individuals with cystic fibrosis (CF), a rare, life-shortening genetic disease. Reductions in healthcare resource utilization (HCRU) associated with ivacaftor have been observed during limited follow-up and for selected outcomes in real-world studies. This study aimed to further describe the long-term impact of ivacaftor treatment on multiple measures of HCRU among people with CF (pwCF). Methods This retrospective study used US commercial and Medicaid claims data from 2011–2018. We included pwCF ≥ 6 years of age with ≥ 1 claim for ivacaftor and 12 months of continuous health plan enrollment before ivacaftor initiation (“pre-ivacaftor” period) who also had 36 months of continuous enrollment and persistent ivacaftor use (i.e., no gap ≥ 90 days between refills) following initiation (“post-ivacaftor” period). We compared comorbidities occurring pre-ivacaftor versus the last 12 months post-ivacaftor. HCRU outcomes included medication use, inpatient admissions, and outpatient office visits. We compared medication use pre-ivacaftor versus the last 12 months post-ivacaftor and inpatient admissions and outpatient office visits pre-ivacaftor versus the post-ivacaftor period annualized across 36 months. Results Seventy-nine pwCF met all criteria, including persistent ivacaftor use during the post-ivacaftor period. Ivacaftor treatment was associated with a significant reduction in pneumonia prevalence (10.1% vs. 26.6%; p

Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.

This study assessed the efficacy of insulin degludec/liraglutide (IDegLira) vs insulin glargine U100 (IGlar) across categories of baseline glycated haemoglobin (HbA1c; ≤7.5%, >7.5% to ≤8.5% and >8.5%), body mass index (BMI

Aims To compare the safety and efficacy of a simpler titration algorithm for insulin degludec/liraglutide (IDegLira) with that used in previous DUAL trials in insulin-naive patients with type 2 diabetes. Research design and methods This 32-week, open-label, non-inferiority trial randomized adults with type 2 diabetes uncontrolled on metformin ± pioglitazone to receive IDegLira, titrated either once weekly, based on the mean of 2 pre-breakfast plasma glucose (PG) readings (n = 210), or twice weekly, based on the mean of 3 pre-breakfast PG readings (n = 210). Results Mean HbA1c decreased from 8.2% (65 mmol/mol) to 6.1% (43 mmol/mol) with once-weekly titration and from 8.1% (65 mmol/mol) to 6.0% (42 mmol/mol) with twice-weekly titration; non-inferiority was confirmed (estimated treatment difference: 0.12% [−0.04; 0.28]95% CI , 1.30 mmol/mol [−0.41; 3.01]95% CI ). Approximately 90% of patients achieved HbA1c

OBJECTIVE Bariatric surgery causes durable weight loss. Gut hormones are implicated in obesity pathogenesis, dietary failure, and mediating gastrointestinal bypass (GIBP) surgery weight loss. In mice, we determined the effects of diet-induced obesity (DIO), subsequent dieting, and GIBP surgery on ghrelin, peptide YY (PYY), and glucagon-like peptide-1 (GLP-1). To evaluate PYY’s role in mediating weight loss post-GIBP, we undertook GIBP surgery in PyyKO mice. RESEARCH DESIGN AND METHODS Male C57BL/6 mice randomized to a high-fat diet or control diet were killed at 4-week intervals. DIO mice underwent switch to ad libitum low-fat diet (DIO-switch) or caloric restriction (CR) for 4 weeks before being killed. PyyKO mice and their DIO wild-type (WT) littermates underwent GIBP or sham surgery and were culled 10 days postoperatively. Fasting acyl-ghrelin, total PYY, active GLP-1 concentrations, stomach ghrelin expression, and colonic Pyy and glucagon expression were determined. Fasting and postprandial PYY and GLP-1 concentrations were assessed 30 days postsurgery in GIBP and sham pair-fed (sham.PF) groups. RESULTS DIO progressively reduced circulating fasting acyl-ghrelin, PYY, and GLP-1 levels. CR and DIO-switch caused weight loss but failed to restore circulating PYY to weight-appropriate levels. After GIBP, WT mice lost weight and exhibited increased circulating fasting PYY and colonic Pyy and glucagon expression. In contrast, the acute effects of GIBP on body weight were lost in PyyKO mice. Fasting PYY and postprandial PYY and GLP-1 levels were increased in GIBP mice compared with sham.PF mice. CONCLUSIONS PYY plays a key role in mediating the early weight loss observed post-GIBP, whereas relative PYY deficiency during dieting may compromise weight-loss attempts.

PI3K signaling is thought to mediate leptin and insulin action in hypothalamic pro-opiomelanocortin (POMC) and agouti-related protein (AgRP) neurons, key regulators of energy homeostasis, through largely unknown mechanisms. We inactivated either p110 alpha or p110 beta PI3K catalytic subunits in these neurons and demonstrate a dominant role for the latter in energy homeostasis; regulation. In POMC neurons, p110 beta inactivation prevented insulin- and leptin-stimulated electrophysiological responses. POMCp110 beta null mice exhibited central leptin resistance, increased adiposity, and diet-induced obesity. In contrast, the response to leptin was not blocked in p110 alpha-deficient POMC neurons. Accordingly, POMCp110 alpha null mice displayed minimal energy homeostasis abnormalities. Similarly, in AgRP neurons, p110 beta had a more important role than p110 alpha. AgRPp110 alpha null mice displayed normal energy homeostasis regulation, whereas AgRPp110 beta null mice were lean, with increased leptin sensitivity and resistance to diet-induced obesity. These results demonstrate distinct metabolic roles for the p110 alpha and p110 beta isoforms; of PI3K in hypothalamic energy regulation.

The last decade has witnessed a marked increase in our understanding of the importance of gut hormones in the regulation of energy homeostasis. In particular, the discovery that the gut hormone peptide YY 3–36 (PYY3–36) reduced feeding in obese rodents and humans fuelled interest in the role of PYY3–36 in body weight regulation. Pharmacological and genetic approaches have revealed that the Y2-receptor mediates the anorectic effects of PYY3–36 whilst mechanistic studies in rodents identified the hypothalamus, vagus and brainstem regions as potential sites of action. More recently, using functional brain imaging techniques in humans, PYY3–36 was found to modulate neuronal activity within hypothalamic and brainstem, and brain regions involved in reward processing. Several lines of evidence suggest that low circulating PYY concentrations predispose towards the development and or maintenance of obesity. Subjects with reduced postprandial PYY release exhibit lower satiety and circulating PYY levels that correlate negatively with markers of adiposity. In addition, mice lacking PYY are hyperphagic and become obese. Conversely, chronic PYY3–36 administration to obese rodents reduces adiposity, and transgenic mice with increased circulating PYY are resistant to diet-induced obesity. Moreover, there is emerging evidence that PYY3–36 may partly mediate the reduced appetite and weight loss benefits observed post-gastric bypass surgery. Taken together these findings, coupled with the retained responsiveness of obese subjects to the effects of PYY3–36, suggest that targeting the PYY system may offer a therapeutic strategy to help treat obesity.

This review discusses recent studies examining the effects of peptide YY on energy homeostasis, highlights the emerging hedonic effects of peptide YY and evaluates the therapeutic potential of the peptide YY system.A role for exogenous PYY3-36 as an anorectic agent in obese humans and rodents has been established and weight loss effects demonstrated in obese rodents. New lines of evidence support a role for endogenous peptide YY in regulating energy homeostasis. The NPY-Y2 receptor mediates the anorectic actions of PYY3-36 with rodent studies implicating the hypothalamus, vagus and brainstem as key target sites. Functional imaging in humans has confirmed that PYY3-36 activates brainstem and hypothalamic regions. The greatest effects, however, were observed within the orbitofrontal cortex, a brain region involved in reward processing. Further evidence for a hedonic role for PYY3-36 is supported by rodent studies showing that PYY3-36 decreases the motivation to seek high-fat food. Rodent studies using selective Y2 agonists and strategies combining PYY3-36/Y2 agonists with other anorectic agents have revealed increased anorectic and weight-reducing effects.Peptide YY plays a role in the integrative regulation of metabolism. The emerging hedonic effects of peptide YY together with the weight-reducing effects observed in obese rodents suggest that targeting the peptide YY system may offer a therapeutic strategy for obesity.

Objectifs Le developpement d’associations insuline basale/analogues du GLP-1 permet de reconsiderer le positionnement des analogues du GLP- 1 dans le traitement du diabete de type 2 (DT2). L’objectif de cette etude est d’evaluer l’efficacite et la tolerance d’une association fixe insuline degludec-Liraglutide (IDegLira) vs. titration optimisee d’une insulinotherapie basale par glargine U100 (IGlar) chez des patients DT2 sous IGlar insuffisamment controles. Patients et methodes Analyse post-hoc de l’etude DUALV menee chez 557 patients DT2 sous 20 a 50 U/jour d’IGlar, randomises 1 :1 entre titration forcee et association IDegLira initiee a 16 DU/jour (16 UI IDeg ; 0,58 mg Lira) avec une cible de glycemie a jeun : 4,0–5,0 mmol/L. Resultats Quelle que soit la dose initiale d’IGlar (20 a 50 U/jour), le recours a l’association IDegLira conditionne une diminution d’HbA1c significativement plus importante et s’accompagne, en comparaison a IGlar, d’une epargne insulinique, d’une reduction ponderale et d’une diminution de frequence d’hypoglycemies (p Discussion L’association IDegLira permet donc d’obtenir un meilleur controle glycemique, une reduction ponderale et une moindre frequence d’hypoglycemies, tout en reduisant les doses d’insuline utilisee, chez des patients DT2 deja insulinotraites. Ceci confirme l’interet des analogues du GLP-1, y compris apres avoir debuter une insulinotherapie basale.

Polymorphisms in the fat mass and obesity-associated gene (FTO) are associated with human obesity and obesity-prone behaviors, including increased food intake and a preference for energy-dense foods. FTO demethylates N 6 -methyladenosine, a potential regulatory RNA modification, but the mechanisms by which FTO predisposes humans to obesity remain unclear. In adiposity-matched, normal-weight humans, we showed that subjects homozygous for the FTO “obesity-risk” rs9939609 A allele have dysregulated circulating levels of the orexigenic hormone acyl-ghrelin and attenuated postprandial appetite reduction. Using functional MRI (fMRI) in normal-weight AA and TT humans, we found that the FTO genotype modulates the neural responses to food images in homeostatic and brain reward regions. Furthermore, AA and TT subjects exhibited divergent neural responsiveness to circulating acyl-ghrelin within brain regions that regulate appetite, reward processing, and incentive motivation. In cell models, FTO overexpression reduced ghrelin mRNA N 6 -methyladenosine methylation, concomitantly increasing ghrelin mRNA and peptide levels. Furthermore, peripheral blood cells from AA human subjects exhibited increased FTO mRNA, reduced ghrelin mRNA N 6 -methyladenosine methylation, and increased ghrelin mRNA abundance compared with TT subjects. Our findings show that FTO regulates ghrelin, a key mediator of ingestive behavior, and offer insight into how FTO obesity-risk alleles predispose to increased energy intake and obesity in humans.

International audience; The effect of peptide tyrosine–tyrosine (PYY) on feeding is well established but currently its role in glucose homeostasis is poorly defined. Here we show in mice, that intraperitoneal (ip) injection of PYY3-36 or Y2R agonist improves nutrient-stimulated glucose tolerance and enhances insulin secretion; an effect blocked by peripheral, but not central, Y2R antagonist administration. Studies on isolated mouse islets revealed no direct effect of PYY3-36 on insulin secretion. Bariatric surgery in mice, enterogastric anastomosis (EGA), improved glucose tolerance in wild-type mice and increased circulating PYY and active GLP-1. In contrast, in Pyy-null mice, post-operative glucose tolerance and active GLP-1 levels were similar in EGA and sham-operated groups. PYY3-36 ip increased hepato-portal active GLP-1 plasma levels, an effect blocked by ip Y2R antagonist. Collectively, these data suggest that PYY3-36 therefore acting via peripheral Y2R increases hepato-portal active GLP-1 plasma levels and improves nutrient-stimulated glucose tolerance.

Background Neuronatin (NNAT) is an endoplasmic reticulum proteolipid implicated in intracellular signalling. Nnat is highly-expressed in the hypothalamus, where it is acutely regulated by nutrients and leptin. Nnat pre-mRNA is differentially spliced to create Nnat-α and -β isoforms. Genetic variation of NNAT is associated with severe obesity. Currently, little is known about the long-term regulation of Nnat. Methods Expression of Nnat isoforms were examined in the hypothalamus of mice in response to acute fast/feed, chronic caloric restriction, diet-induced obesity and modified gastric bypass surgery. Nnat expression was assessed in the central nervous system and gastrointestinal tissues. RTqPCR was used to determine isoform-specific expression of Nnat mRNA. Results Hypothalamic expression of both Nnat isoforms was comparably decreased by overnight and 24-h fasting. Nnat expression was unaltered in diet-induced obesity, or subsequent switch to a calorie restricted diet. Nnat isoforms showed differential expression in the hypothalamus but not brainstem after bypass surgery. Hypothalamic Nnat-β expression was significantly reduced after bypass compared with sham surgery (P = 0.003), and was positively correlated with post-operative weight-loss (R2 = 0.38, P = 0.01). In contrast, Nnat-α expression was not suppressed after bypass surgery (P = 0.19), and expression did not correlate with reduction in weight after surgery (R2 = 0.06, P = 0.34). Hypothalamic expression of Nnat-β correlated weakly with circulating leptin, but neither isoform correlated with fasting gut hormone levels post- surgery. Nnat expression was detected in brainstem, brown-adipose tissue, stomach and small intestine. Conclusions Nnat expression in hypothalamus is regulated by short-term nutrient availability, but unaltered by diet-induced obesity or calorie restriction. While Nnat isoforms in the hypothalamus are co-ordinately regulated by acute nutrient supply, after modified gastric bypass surgery Nnat isoforms show differential expression. These results raise the possibility that in the radically altered nutrient and hormonal milieu created by bypass surgery, resultant differential splicing of Nnat pre-mRNA may contribute to weight-loss.

PYY is a gut-derived putative satiety signal released in response to nutrient ingestion and is implicated in the regulation of energy homeostasis. Pyy-expressing neurons have been identified in the hindbrain of river lamprey, rodents, and primates. Despite this high evolutionary conservation, little is known about central PYY neurons. Using in situ hybridization, PYY-Cre;ROSA-EYFP mice, and immunohistochemistry, we identified PYY cell bodies in the gigantocellular reticular nucleus region of the hindbrain. PYY projections were present in the dorsal vagal complex and hypoglossal nucleus. In the hindbrain, Pyy mRNA was present at E9.5, and expression peaked at P2 and then decreased significantly by 70% at adulthood. We found that, in contrast to the circulation, PYY-(1–36) is the predominant isoform in mouse brainstem extracts in the ad libitum-fed state. However, following a 24-h fast, the relative amounts of PYY-(1–36) and PYY-(3–36) isoforms were similar. Interestingly, central Pyy expression showed nutritional regulation and decreased significantly by acute starvation, prolonged caloric restriction, and bariatric surgery (enterogastroanastomosis). Central Pyy expression correlated with body weight loss and circulating leptin and PYY concentrations. Central regulation of energy metabolism is not limited to the hypothalamus but also includes the midbrain and the brainstem. Our findings suggest a role for hindbrain PYY in the regulation of energy homeostasis and provide a starting point for further research on gigantocellular reticular nucleus PYY neurons, which will increase our understanding of the brain stem pathways in the integrated control of appetite and energy metabolism.

Background & Aims Gut hormones represent attractive therapeutic targets for the treatment of obesity and type 2 diabetes. However, controversy surrounds the effects that adiposity, dietary manipulations, and bariatric surgery have on their circulating concentrations. We sought to determine whether these discrepancies are due to methodologic differences. Methods Ten normal-weight males participated in a 4-way crossover study investigating whether fasting appetite scores, plasma acyl-ghrelin, active glucagon-like peptide-1 (GLP-1), and peptide YY3–36 (PYY3–36) levels are altered by study-induced stress, prior food consumption, and sample processing. Results Study visit order affected anxiety, plasma cortisol, and temporal profiles of appetite and plasma PYY3–36, with increased anxiety and cortisol concentrations on the first study day. Plasma cortisol area under the curve (AUC) correlated positively with plasma PYY3–36 AUC. Despite a 14-hour fast, baseline hunger, PYY3–36 concentrations, temporal appetite profiles, PYY3–36 AUC, and active GLP-1 were affected by the previous evening's meal. Sample processing studies revealed that sample acidification and esterase inhibition are required when measuring acyl-ghrelin and dipeptidyl-peptidase IV inhibitor addition for active GLP-1. However, plasma PYY3–36 concentrations were unaffected by addition of dipeptidyl-peptidase IV. Conclusions Accurate assessment of appetite, feeding behavior, and gut hormone concentrations requires standardization of prior food consumption and subject acclimatization to the study protocol. Moreover, because of the labile nature of acyl-ghrelin and active GLP-1, specialized sample processing needs to be undertaken.

Losing weight can pose a challenge, but how to avoid putting those pounds back on can be a real struggle. A major health problem for obese people is that diseases linked to obesity, such as type 2 diabetes and cardiovascular disease, put their lives at risk, even in young individuals. Although bariatric surgery-a surgical method to reduce or modify the gastrointestinal tract-was originally envisioned for the most severe cases of obesity, evidence suggests that the benefit of this procedure may not be limited to the staggering weight loss it causes. Endogenous factors released from the gut, and modified after surgery, may explain why bariatric surgery can be beneficial for obesity-related diseases and why operated individuals successfully maintain the weight loss. In 'Bedside to Bench,' Rachel Larder and Stephen O'Rahilly peruse a human study with dieters who regained weight despite a successful diet. Appetite-regulating hormones in the gut may be responsible for this relapse in the long term. In 'Bench to Bedside,' Keval Chandarana and Rachel Batterham examine how two different methods of bariatric surgery highlight the relevance of gut-derived hormones not only in inducing sustained weight loss but also in improving glucose homeostasis. These insights may open new avenues to bypass the surgery and obtain the same results with targeted drugs.

SummaryDietary protein enhances satiety and promotes weight loss, but the mechanisms by which appetite is affected remain unclear. We investigated the role of gut hormones, key regulators of ingestive behavior, in mediating the satiating effects of different macronutrients. In normal-weight and obese human subjects, high-protein intake induced the greatest release of the anorectic hormone peptide YY (PYY) and the most pronounced satiety. Long-term augmentation of dietary protein in mice increased plasma PYY levels, decreased food intake, and reduced adiposity. To directly determine the role of PYY in mediating the satiating effects of protein, we generated Pyy null mice, which were selectively resistant to the satiating and weight-reducing effects of protein and developed marked obesity that was reversed by exogenous PYY treatment. Our findings suggest that modulating the release of endogenous satiety factors, such as PYY, through alteration of specific diet constituents could provide a rational therapy for obesity.