Weight-loss maintenance is accompanied by interconnected alterations in circulating FGF21-adiponectin-leptin and bioactive sphingolipids.

Weight loss is often followed by weight regain. Characterizing endocrine alterations accompanying weight reduction and regain may disentangle the complex biology of weight-loss maintenance. Here, we profile energy-balance-regulating metabokines and sphingolipids in adults with obesity undergoing an initial low-calorie diet-induced weight loss and a subsequent weight-loss maintenance phase with exercise, glucagon-like peptide-1 (GLP-1) analog therapy, both combined, or placebo. We show that circulating growth differentiation factor 15 (GDF15) and C16:0-C18:0 ceramides transiently increase upon initial diet-induced weight loss. Conversely, circulating fibroblast growth factor 21 (FGF21) is downregulated following weight-loss maintenance with combined exercise and GLP-1 analog therapy, coinciding with increased adiponectin, decreased leptin, and overall decrements in ceramide and sphingosine-1-phosphate levels. Subgroup analyses reveal differential alterations in FGF21-adiponectin-leptin-sphingolipids between weight maintainers and regainers. Clinically, cardiometabolic health outcomes associate with selective metabokine-sphingolipid remodeling signatures. Collectively, our findings indicate distinct FGF21, GDF15, and ceramide responses to diverse phases of weight change and suggest that weight-loss maintenance involves alterations within the metabokine-sphingolipid axis.

In-depth phosphoproteomic profiling of the insulin signaling response in heart tissue and cardiomyocytes unveils canonical and specialized regulation.

BACKGROUND: Insulin signaling regulates cardiac substrate utilization and is implicated in physiological adaptations of the heart. Alterations in the signaling response within the heart are believed to contribute to pathological conditions such as type-2 diabetes and heart failure. While extensively investigated in several metabolic organs using phosphoproteomic strategies, the signaling response elicited in cardiac tissue in general, and specifically in the specialized cardiomyocytes, has not yet been investigated to the same extent. METHODS: Insulin or vehicle was administered to male C57BL6/JRj mice via intravenous injection into the vena cava. Ventricular tissue was extracted and subjected to quantitative phosphoproteomics analysis to evaluate the insulin signaling response. To delineate the cardiomyocyte-specific response and investigate the role of Tbc1d4 in insulin signal transduction, cardiomyocytes from the hearts of cardiac and skeletal muscle-specific Tbc1d4 knockout mice, as well as from wildtype littermates, were studied. The phosphoproteomic studies involved isobaric peptide labeling with Tandem Mass Tags (TMT), enrichment for phosphorylated peptides, fractionation via micro-flow reversed-phase liquid chromatography, and high-resolution mass spectrometry measurements. RESULTS: We quantified 10,399 phosphorylated peptides from ventricular tissue and 12,739 from isolated cardiomyocytes, localizing to 3,232 and 3,128 unique proteins, respectively. In cardiac tissue, we identified 84 insulin-regulated phosphorylation events, including sites on the Insulin Receptor (InsrY1351, Y1175, Y1179, Y1180) itself as well as the Insulin receptor substrate protein 1 (Irs1S522, S526). Predicted kinases with increased activity in response to insulin stimulation included Rps6kb1, Akt1 and Mtor. Tbc1d4 emerged as a major phosphorylation target in cardiomyocytes. Despite limited impact on the global phosphorylation landscape, Tbc1d4 deficiency in cardiomyocytes attenuated insulin-induced Glut4 translocation and induced protein remodeling. We observed 15 proteins significantly regulated upon knockout of Tbc1d4. While Glut4 exhibited decreased protein abundance consequent to Tbc1d4-deficiency, Txnip levels were notably increased. Stimulation of wildtype cardiomyocytes with insulin led to the regulation of 262 significant phosphorylation events, predicted to be regulated by kinases such as Akt1, Mtor, Akt2, and Insr. In cardiomyocytes, the canonical insulin signaling response is elicited in addition to regulation on specialized cardiomyocyte proteins, such as Kcnj11Y12 and DspS2597. Details of all phosphorylation sites are provided. CONCLUSION: We present a first global outline of the insulin-induced phosphorylation signaling response in heart tissue and in isolated adult cardiomyocytes, detailing the specific residues with changed phosphorylation abundances. Our study marks an important step towards understanding the role of insulin signaling in cardiac diseases linked to insulin resistance.

Altered desensitization and internalization patterns of rodent versus human glucose-dependent insulinotropic polypeptide (GIP) receptors. An important drug discovery challenge.

BACKGROUND AND PURPOSE: The gut hormone glucose-dependent insulinotropic polypeptide (GIP) signals via the GIP receptor (GIPR), resulting in postprandial potentiation of glucose-stimulated insulin secretion. The translation of results from rodent studies to human studies has been challenged by the unexpected effects of GIPR-targeting compounds. We, therefore, investigated the variation between species, focusing on GIPR desensitization and the role of the receptor C-terminus. EXPERIMENTAL APPROACH: The GIPR from humans, mice, rats, pigs, dogs and cats was studied in vitro for cognate ligand affinity, G protein activation (cAMP accumulation), recruitment of beta-arrestin and internalization. Variants of the mouse, rat and human GIPRs with swapped C-terminal tails were studied in parallel. KEY RESULTS: The human GIPR is more prone to internalization than rodent GIPRs. Despite similar agonist affinities and potencies for Gαs activation, especially, the mouse GIPR shows reduced receptor desensitization, internalization and beta-arrestin recruitment. Using an enzyme-stabilized, long-acting GIP analogue, the species differences were even more pronounced. 'Tail-swapped' human, rat and mouse GIPRs were all fully functional in their Gαs coupling, and the mouse GIPR regained internalization and beta-arrestin 2 recruitment properties with the human tail. The human GIPR lost the ability to recruit beta-arrestin 2 when its own C-terminus was replaced by the rat or mouse tail. CONCLUSIONS AND IMPLICATIONS: Desensitization of the human GIPR is dependent on the C-terminal tail. The species-dependent functionality of the C-terminal tail and the different species-dependent internalization patterns, especially between human and mouse GIPRs, are important factors influencing the preclinical evaluation of GIPR-targeting therapeutic compounds.

Bone remodeling in survivors of pediatric hematopoietic stem cell transplantation: Impact of heavy resistance training.

BACKGROUND: Early-onset osteoporosis is a frequent late effect after pediatric hematopoietic stem cell transplantation (HSCT). It remains unknown if physical training can improve bone formation in these patients, as the transplantation procedure may cause sustained dysregulation of the bone-forming osteoblast progenitor cells. OBJECTIVE: We aimed to explore the effect of resistance training on bone remodeling in long-term survivors of pediatric HSCT. PROCEDURE: In this prospective, controlled intervention study, we included seven HSCT survivors and 15 age- and sex-matched healthy controls. The participants completed a 12-week heavy load, lower extremity resistance training intervention with three weekly sessions. We measured fasting serum levels of the bone formation marker "N-terminal propeptide of type I procollagen" (P1NP), and the bone resorption marker "C-terminal telopeptide of type I collagen" (CTX). The hypothesis was planned before data collection began. The trial was registered at Clinicaltrials.gov before including the first participant, with trial registration no. NCT04922970. RESULTS: Resistance training led to significantly increased levels of fasting P1NP in both patients (from 57.62 to 114.99 ng/mL, p = .03) and controls (from 66.02 to 104.62 ng/mL, p < .001). No significant changes in fasting CTX levels were observed. CONCLUSIONS: Despite previous high-dose cytotoxic therapy, long-term survivors of pediatric HSCT respond to resistance training with improvement of bone formation, comparable to that of healthy controls. This suggests that resistance training might be a promising non-pharmacological approach to prevent the early decline in bone mass, and should be considered as part of a follow-up program to counteract long-term sequela after pediatric HSCT.

L-valine is a powerful stimulator of GLP-1 secretion in rodents and stimulates secretion through ATP-sensitive potassium channels and voltage-gated calcium channels.

BACKGROUND: We previously reported that, among all the naturally occurring amino acids, L-valine is the most powerful luminal stimulator of glucagon-like peptide 1 (GLP-1) release from the upper part of the rat small intestine. This makes L-valine an interesting target for nutritional-based modulation of GLP-1 secretion. However, the molecular mechanism of L-valine-induced secretion remains unknown. METHODS: We aimed to investigate the effect of orally given L-valine in mice and to identify the molecular details of L-valine stimulated GLP-1 release using the isolated perfused rat small intestine and GLUTag cells. In addition, the effect of L-valine on hormone secretion from the distal intestine was investigated using a perfused rat colon. RESULTS: Orally given L-valine (1 g/kg) increased plasma levels of active GLP-1 comparably to orally given glucose (2 g/kg) in male mice, supporting that L-valine is a powerful stimulator of GLP-1 release in vivo (P > 0.05). Luminal L-valine (50 mM) strongly stimulated GLP-1 release from the perfused rat small intestine (P < 0.0001), and inhibition of voltage-gated Ca2+-channels with nifedipine (10 µM) inhibited the GLP-1 response (P < 0.01). Depletion of luminal Na+ did not affect L-valine-induced GLP-1 secretion (P > 0.05), suggesting that co-transport of L-valine and Na+ is not important for the depolarization necessary to activate the voltage-gated Ca2+-channels. Administration of the KATP-channel opener diazoxide (250 µM) completely blocked the L-valine induced GLP-1 response (P < 0.05), suggesting that L-valine induced depolarization arises from metabolism and opening of KATP-channels. Similar to the perfused rat small intestine, L-valine tended to stimulate peptide tyrosine-tyrosine (PYY) and GLP-1 release from the perfused rat colon. CONCLUSIONS: L-valine is a powerful stimulator of GLP-1 release in rodents. We propose that intracellular metabolism of L-valine leading to closure of KATP-channels and opening of voltage-gated Ca2+-channels are involved in L-valine induced GLP-1 secretion.

Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial.

Importance: A major concern with weight loss is concomitant bone loss. Exercise and glucagon-like peptide-1 receptor agonists (GLP-1RAs) represent weight loss strategies that may protect bone mass despite weight loss. Objective: To investigate bone health at clinically relevant sites (hip, spine, and forearm) after diet-induced weight loss followed by a 1-year intervention with exercise, liraglutide, or both combined. Design, Setting, and Participants: This study was a predefined secondary analysis of a randomized clinical trial conducted between August 2016 and November 2019 at the University of Copenhagen and Hvidovre Hospital in Denmark. Eligible participants included adults aged 18 to 65 years with obesity (body mass index of 32-43) and without diabetes. Data analysis was conducted from March to April 2023, with additional analysis in February 2024 during revision. Interventions: After an 8-week low-calorie diet (800 kcal/day), participants were randomized to 1 of 4 groups for 52 weeks: a moderate- to vigorous-intensity exercise program (exercise alone), 3.0 mg daily of the GLP-1 RA liraglutide (liraglutide alone), the combination, or placebo. Main Outcomes and Measures: The primary outcome was change in site-specific bone mineral density (BMD) at the hip, lumbar spine, and distal forearm from before the low-calorie diet to the end of treatment, measured by dual-energy x-ray absorptiometry in the intention-to-treat population. Results: In total, 195 participants (mean [SD] age, 42.84 [11.87] years; 124 female [64%] and 71 male [36%]; mean [SD] BMI, 37.00 [2.92]) were randomized, with 48 participants in the exercise group, 49 participants in the liraglutide group, 49 participants in the combination group, and 49 participants in the placebo group. The total estimated mean change in weight losses during the study was 7.03 kg (95% CI, 4.25-9.80 kg) in the placebo group, 11.19 kg (95% CI, 8.40-13.99 kg) in the exercise group, 13.74 kg (95% CI, 11.04-16.44 kg) in the liraglutide group, and 16.88 kg (95% CI, 14.23-19.54 kg) in the combination group. In the combination group, BMD was unchanged compared with the placebo group at the hip (mean change, -0.006 g/cm2; 95% CI, -0.017 to 0.004 g/cm2; P = .24) and lumbar spine (-0.010 g/cm2; 95% CI, -0.025 to 0.005 g/cm2; P = .20). Compared with the exercise group, BMD decreased for the liraglutide group at the hip (mean change, -0.013 g/cm2; 95% CI, -0.024 to -0.001 g/cm2; P = .03) and spine (mean change, -0.016 g/cm2; 95% CI, -0.032 to -0.001 g/cm2; P = .04). Conclusions and Relevance: In this randomized clinical trial, the combination of exercise and GLP-1RA (liraglutide) was the most effective weight loss strategy while preserving bone health. Liraglutide treatment alone reduced BMD at clinically relevant sites more than exercise alone despite similar weight loss. Trial Registration: EudraCT: 2015-005585-32.

The impact of short-term eucaloric low- and high-carbohydrate diets on liver triacylglycerol content in males with overweight and obesity: a randomized crossover study.

BACKGROUND: Intrahepatic triacylglycerol (liver TG) content is associated with hepatic insulin resistance and dyslipidemia. Liver TG content can be modulated within days under hypocaloric conditions. OBJECTIVES: We hypothesized that 4 d of eucaloric low-carbohydrate/high-fat (LC) intake would decrease liver TG content, whereas a high-carbohydrate/low-fat (HC) intake would increase liver TG content, and further that alterations in liver TG would be linked to dynamic changes in hepatic glucose and lipid metabolism. METHODS: A randomized crossover trial in males with 4 d + 4 d of LC and HC, respectively, with ≥2 wk of washout. 1H-magnetic resonance spectroscopy (1H-MRS) was used to measure liver TG content, with metabolic testing before and after intake of an LC diet (11E% carbohydrate corresponding to 102 ± 12 {mean ± standard deviation [SD]) g/d, 70E% fat} and an HC diet (65E% carbohydrate corresponding to 537 ± 56 g/d, 16E% fat). Stable [6,6-2H2]-glucose and [1,1,2,3,3-D5]-glycerol tracer infusions combined with hyperinsulinemic-euglycemic clamps and indirect calorimetry were used to measure rates of hepatic glucose production and lipolysis, whole-body insulin sensitivity and substrate oxidation. RESULTS: Eleven normoglycemic males with overweight or obesity (BMI 31.6 ± 3.7 kg/m2) completed both diets. The LC diet reduced liver TG content by 35.3% (95% confidence interval: -46.6, -24.1) from 4.9% [2.4-11.0] (median interquartile range) to 2.9% [1.4-6.9], whereas there was no change after the HC diet. After the LC diet, fasting whole-body fat oxidation and plasma beta-hydroxybutyrate concentration increased, whereas markers of de novo lipogenesis (DNL) diminished. Fasting plasma TG and insulin concentrations were lowered and the hepatic insulin sensitivity index increased after LC. Peripheral glucose disposal was unchanged. CONCLUSIONS: Reduced carbohydrate and increased fat intake for 4 d induced a marked reduction in liver TG content and increased hepatic insulin sensitivity. Increased rates of fat oxidation and ketogenesis combined with lower rates of DNL are suggested to be responsible for lowering liver TG. This trial was registered at clinicaltrials.gov as NCT04581421.

Glucagon agonism in the treatment of metabolic diseases including type 2 diabetes mellitus and obesity.

Type 2 diabetes mellitus (T2DM) is associated with obesity and, therefore, it is important to target both overweight and hyperglycaemia. Glucagon plays important roles in glucose, amino acid and fat metabolism and may also regulate appetite and energy expenditure. These physiological properties are currently being exploited therapeutically in several compounds, most often in combination with glucagon-like peptide-1 (GLP-1) agonism in the form of dual agonists. With this combination, increases in hepatic glucose production and hyperglycaemia, which would be counterproductive, are largely avoided. In multiple randomized trials, the co-agonists have been demonstrated to lead to significant weight loss and, in participants with T2DM, even improved glycated haemoglobin (HbA1c) levels. In addition, significant reductions in hepatic fat content have been observed. Here, we review and discuss the studies so far available. Twenty-six randomized trials of seven different GLP-1 receptor (GLP-1R)/glucagon receptor (GCGR) co-agonists were identified and reviewed. GLP-1R/GCGR co-agonists generally provided significant weight loss, reductions in hepatic fat content, improved lipid profiles, insulin secretion and sensitivity, and in some cases, improved HbA1c levels. A higher incidence of adverse effects was present with GLP-1R/GCGR co-agonist treatment than with GLP-1 agonist monotherapy or placebo. Possible additional risks associated with glucagon agonism are also discussed. A delicate balance between GLP-1 and glucagon agonism seems to be of particular importance. Further studies exploring the optimal ratio of GLP-1 and glucagon receptor activation and dosage and titration regimens are needed to ensure a sufficient safety profile while providing clinical benefits.

Effect of the glucagon-like peptide-1 (GLP-1) receptor agonist semaglutide on alcohol consumption in alcohol-preferring male vervet monkeys.

RATIONALE: Glucagon-like peptide-1 (GLP-1) receptor agonists reduce alcohol consumption in rodents and non-human primates. Semaglutide is a new long-acting GLP-1 receptor agonist, widely used in the clinic against type 2 diabetes and obesity. It is also reported to reduce alcohol intake in rodents. OBJECTIVES: This study investigates the possible inhibitory effect of semaglutide on alcohol intake in alcohol-preferring African green monkeys. METHODS: We performed a vehicle-controlled study on male monkeys that had demonstrated a preference for alcohol. In the monkeys selected for voluntary alcohol drinking, alcohol consumption was measured for ten days at baseline (Monday to Friday for two weeks). During this period, the monkeys had access to alcohol 4 h per day and free access to water 24 h per day. After two weeks of baseline measurements, the monkeys were randomized to semaglutide or vehicle. Each group consisted of ten monkeys, and the two groups were balanced with respect to baseline alcohol intake. Following the baseline period, the monkeys were treated with escalating doses of semaglutide (up to 0.05 mg/kg) or vehicle subcutaneously twice weekly for two weeks during which period alcohol was not available. After uptitration, the monkeys had access to alcohol 4 h daily for 20 days (Monday to Friday for 4 weeks), and alcohol consumption was measured. During this alcohol exposure period, treatment with semaglutide (0.05 mg/kg twice weekly) or vehicle continued for three weeks followed by a one-week washout period. RESULTS: Compared to the vehicle, semaglutide significantly reduced alcohol intake. There were no signs of emetic events or changes in water intake. CONCLUSIONS: These data demonstrate for the first time the potent effect of semaglutide in reducing voluntary alcohol intake in non-human primates and further substantiate the need for clinical trials investigating the effect of semaglutide in patients with alcohol-use disorder.

GLP-1 increases heart rate by a direct action on the sinus node.

AIMS: Glucagon-like peptide-1 receptor agonists (GLP-1 RAs) are increasingly used to treat type 2 diabetes and obesity. Albeit cardiovascular outcomes generally improve, treatment with GLP-1 RAs is associated with increased heart rate, the mechanism of which is unclear. METHODS AND RESULTS: We employed a large animal model, the female landrace pig, and used multiple in-vivo and ex-vivo approaches including pharmacological challenges, electrophysiology and high-resolution mass spectrometry to explore how GLP-1 elicits an increase in heart rate. In anaesthetized pigs, neither cervical vagotomy, adrenergic blockers (alpha, beta or combined alpha-beta blockade), ganglionic blockade (hexamethonium) nor inhibition of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels (ivabradine) abolished the marked chronotropic effect of GLP-1. GLP-1 administration to isolated perfused pig hearts also increased heart rate, which was abolished by GLP-1 receptor blockade. Electrophysiological characterization of GLP-1 effects in vivo and in isolated perfused hearts localized electrical modulation to the atria and conduction system. In isolated sinus nodes, GLP-1 administration shortened action potential cycle length of pacemaker cells and shifted the site of earliest activation. The effect was independent of HCN blockade. Collectively, these data support a direct effect of GLP-1 on GLP-1 receptors within the heart. Consistently, single nucleus RNA sequencing (snRNAseq) showed GLP-1 receptor expression in porcine pacemaker cells. Quantitative phosphoproteomics analyses of sinus node samples revealed that GLP-1 administration leads to phosphorylation changes of calcium cycling proteins of the sarcoplasmic reticulum, known to regulate heart rate. CONCLUSION: GLP-1 has direct chronotropic effects on the heart mediated by GLP-1 receptors in pacemaker cells of the sinus node, inducing changes in action potential morphology and the leading pacemaker site through a calcium signaling response characterized by PKA-dependent phosphorylation of Ca2+ cycling proteins involved in pace making. Targeting the pacemaker calcium clock may be a strategy to lower heart rate in GLP-1 RA recipients.

Impact of Synbiotic Intake on Liver Metabolism in Metabolically Healthy Participants and Its Potential Preventive Effect on Metabolic-Dysfunction-Associated Fatty Liver Disease (MAFLD): A Randomized, Placebo-Controlled, Double-Blinded Clinical Trial.

Synbiotics modulate the gut microbiome and contribute to the prevention of liver diseases such as metabolic-dysfunction-associated fatty liver disease (MAFLD). This study aimed to evaluate the effect of a randomized, placebo-controlled, double-blinded seven-week intervention trial on the liver metabolism in 117 metabolically healthy male participants. Anthropometric data, blood parameters, and stool samples were analyzed using linear mixed models. After seven weeks of intervention, there was a significant reduction in alanine aminotransferase (ALT) in the synbiotic group compared to the placebo group (-14.92%, CI: -26.60--3.23%, p = 0.013). A stratified analysis according to body fat percentage revealed a significant decrease in ALT (-20.70%, CI: -40.88--0.53%, p = 0.045) in participants with an elevated body fat percentage. Further, a significant change in microbiome composition (1.16, CI: 0.06-2.25, p = 0.039) in this group was found, while the microbial composition remained stable upon intervention in the group with physiological body fat. The 7-week synbiotic intervention reduced ALT levels, especially in participants with an elevated body fat percentage, possibly due to modulation of the gut microbiome. Synbiotic intake may be helpful in delaying the progression of MAFLD and could be used in addition to the recommended lifestyle modification therapy.

Effects of 3 months of 10-h per-day time-restricted eating and 3 months of follow-up on bodyweight and cardiometabolic health in Danish individuals at high risk of type 2 diabetes: the RESET single-centre, parallel, superiority, open-label, randomised controlled trial.

BACKGROUND: Time-restricted eating (TRE) has been suggested to be a simple, feasible, and effective dietary strategy for individuals with overweight or obesity. We aimed to investigate the effects of 3 months of 10-h per-day TRE and 3 months of follow-up on bodyweight and cardiometabolic risk factors in individuals at high risk of type 2 diabetes. METHODS: This was a single-centre, parallel, superiority, open-label randomised controlled clinical trial conducted at Steno Diabetes Center Copenhagen (Denmark). The inclusion criteria were age 30-70 years with either overweight (ie, BMI ≥25 kg/m2) and concomitant prediabetes (ie, glycated haemoglobin [HbA1c] 39-47 mmol/mol) or obesity (ie, BMI ≥30 kg/m2) with or without prediabetes and a habitual self-reported eating window (eating and drinking [except for water]) of 12 h per day or more every day and of 14 h per day or more at least 1 day per week. Individuals were randomly assigned 1:1 to 3 months of habitual living (hereafter referred to as the control group) or TRE, which was a self-selected 10-h per-day eating window placed between 0600 h and 2000 h. Randomisation was done in blocks varying in size and was open for participants and research staff, but outcome assessors were masked during statistical analyses. The randomisation list was generated by an external statistician. The primary outcome was change in bodyweight, assessed after 3 months (12 weeks) of the intervention and after 3 months (13 weeks) of follow-up. Adverse events were reported and registered at study visits or if participants contacted study staff to report events between visits. This trial is registered on ClinicalTrials.gov (NCT03854656). FINDINGS: Between March 12, 2019, and March 2, 2022, 100 participants (66 [66%] were female and 34 [34%] were male; median age 59 years [IQR 52-65]) were enrolled and randomly assigned (50 to each group). Of those 100, 46 (92%) in the TRE group and 46 (92%) in the control group completed the intervention period. After 3 months of the intervention, there was no difference in bodyweight between the TRE group and the control group (-0·8 kg, 95% CI -1·7 to 0·2; p=0·099). Being in the TRE group was not associated with a lower bodyweight compared with the control group after subsequent 3-month follow-up (-0·2 kg, -1·6 to 1·2). In the per-protocol analysis, participants who completed the intervention in the TRE group lost 1·0 kg (-1·9 to -0·0; p=0·040) bodyweight compared with the control group after 3 months of intervention, which was not maintained after the 3-month follow-up period (-0·4 kg, -1·8 to 1·0). During the trial and follow-up period, one participant in the TRE group reported a severe adverse event: development of a subcutaneous nodule and pain when the arm was in use. This side-effect was evaluated to be related to the trial procedures. INTERPRETATION: 3 months of 10-h per-day TRE did not lead to clinically relevant effects on bodyweight in middle-aged to older individuals at high risk of type 2 diabetes. FUNDING: Novo Nordisk Foundation, Aalborg University, Helsefonden, and Innovation Fund Denmark.

Healthy weight loss maintenance with exercise, GLP-1 receptor agonist, or both combined followed by one year without treatment: a post-treatment analysis of a randomised placebo-controlled trial.

Background: New obesity medications result in large weight losses. However, long-term adherence in a real-world setting is challenging, and termination of obesity medication results in weight regain towards pre-treatment body weight. Therefore, we investigated whether weight loss and improved body composition are sustained better at 1 year after termination of active treatment with glucagon-like peptide-1 (GLP-1) receptor agonist, supervised exercise program, or both combined for 1 year. Methods: We conducted a post-treatment study in extension of a randomised, controlled trial in Copenhagen. Adults with obesity (aged 18-65 years and initial body mass index 32-43 kg/m2) completed an eight-week low-calorie diet-induced weight loss of 13.1 kg (week -8 to 0) and were randomly allocated (1:1:1:1) to one-year weight loss maintenance (week 0-52) with either supervised exercise, the GLP-1 receptor agonist once-daily subcutaneous liraglutide 3.0 mg, the combination of exercise and liraglutide, or placebo. 166 Participants completed the weight loss maintenance phase. All randomised participants were invited to participate in the post-treatment study with outcome assessments one year after treatment termination, at week 104. The primary outcome of the post-treatment assessment was change in body weight from after the initial weight loss (at randomisation, week 0) to one year after treatment termination (week 104) in the intention-to-treat population. The secondary outcome was change in body-fat percentage (week 0-104). The study is registered with EudraCT, 2015-005585-32, and with ClinicalTrials.gov, NCT04122716. Findings: Between Dec 17, 2018, and Dec 17, 2020, 109 participants attended the post-treatment study. From randomisation to one year after termination of combined exercise and liraglutide treatment (week 0-104), participants had reduced body weight (-5.1 kg [95% CI -10.0; -0.2]; P = 0.040) and body-fat percentage (-2.3%-points [-4.3 to -0.3]; P = 0.026) compared with after termination of liraglutide alone. More participants who had previously received combination treatment maintained a weight loss of at least 10% of initial body weight one year after treatment termination (week -8 to 104) compared with participants who had previously received placebo (odds ratio [OR] 7.2 [2.4; 21.3]) and liraglutide (OR 4.2 [1.6; 10.8]). More participants who had previously received supervised exercise maintained a weight loss of at least 10% compared with placebo (OR 3.7 [1.2; 11.1]). During the year after termination of treatment (week 52-104), weight regain was 6.0 kg [2.1; 10.0] larger after termination of liraglutide compared with after termination of supervised exercise and 2.5 kg [-1.5 to 6.5] compared with after termination of combination treatment. Interpretation: The addition of supervised exercise to obesity pharmacotherapy seems to improve healthy weight maintenance after treatment termination compared with treatment termination of obesity pharmacotherapy alone. Body weight and body composition were maintained one year after termination of supervised exercise, in contrast to weight regain after termination of treatment with obesity pharmacotherapy alone. Funding: Helsefonden and the Novo Nordisk Foundation.

New Lessons from the gut: Studies of the role of gut peptides in weight loss and diabetes resolution after gastric bypass and sleeve gastrectomy.

It has been known since 2005 that the secretion of several gut hormones changes radically after gastric bypass operations and, although more moderately, after sleeve gastrectomy but not after gastric banding. It has therefore been speculated that increased secretion of particularly GLP-1 and Peptide YY (PYY), which both inhibit appetite and food intake, may be involved in the weight loss effects of surgery and for improvements in glucose tolerance. Experiments involving inhibition of hormone secretion with somatostatin, blockade of their actions with antagonists, or blockade of hormone formation/activation support this notion. However, differences between results of bypass and sleeve operations indicate that distinct mechanisms may also be involved. Although the reductions in ghrelin secretion after sleeve gastrectomy would seem to provide an obvious explanation, experiments with restoration of ghrelin levels pointed towards effects on insulin secretion and glucose tolerance rather than on food intake. It seems clear that changes in GLP-1 secretion are important for insulin secretion after bypass and appear to be responsible for postbariatric hypoglycemia in glucose-tolerant individuals; however, with time the improvements in insulin sensitivity, which in turn are secondary to the weight loss, may be more important. Changes in bile acid metabolism do not seem to be of particular importance in humans.

Dietary impact on fasting and stimulated GLP-1 secretion in different metabolic conditions - a narrative review.

Glucagon-like peptide 1 (GLP-1), a gastrointestinal peptide and central mediator of glucose metabolism, is secreted by L cells in the intestine in response to food intake. Postprandial secretion of GLP-1 is triggered by nutrient-sensing via transporters and G-protein-coupled receptors (GPCRs). GLP-1 secretion may be lower in adults with obesity/overweight (OW) or type 2 diabetes mellitus (T2DM) than in those with normal glucose tolerance (NGT), but these findings are inconsistent. Because of the actions of GLP-1 on stimulating insulin secretion and promoting weight loss, GLP-1 and its analogs are used in pharmacologic preparations for the treatment of T2DM. However, physiologically stimulated GLP-1 secretion through the diet might be a preventive or synergistic method for improving glucose metabolism in individuals who are OW, or have impaired glucose tolerance (IGT) or T2DM. This narrative review focuses on fasting and postprandial GLP-1 secretion in individuals with different metabolic conditions and degrees of glucose intolerance. Further, the influence of relevant diet-related factors (e.g., specific diets, meal composition, and size, phytochemical content, and gut microbiome) that could affect fasting and postprandial GLP-1 secretion are discussed. Some studies showed diminished glucose- or meal-stimulated GLP-1 response in participants with T2DM, IGT, or OW compared with those with NGT, whereas other studies have reported an elevated or unchanged GLP-1 response in T2DM or IGT. Meal composition, especially the relationship between macronutrients and interventions targeting the microbiome can impact postprandial GLP-1 secretion, although it is not clear which macronutrients are strong stimulants of GLP-1. Moreover, glucose tolerance, antidiabetic treatment, grade of overweight/obesity, and sex were important factors influencing GLP-1 secretion. The results presented in this review highlight the potential of nutritional and physiologic stimulation of GLP-1 secretion. Further research on fasting and postprandial GLP-1 concentrations and the resulting metabolic consequences under different metabolic conditions is needed.

The role of empagliflozin-induced metabolic changes for cardiac function in patients with type 2 diabetes. A randomized cross-over magnetic resonance imaging study with insulin as comparator.

BACKGROUND: Metabolic effects of empagliflozin treatment include lowered glucose and insulin concentrations, elevated free fatty acids and ketone bodies and have been suggested to contribute to the cardiovascular benefits of empagliflozin treatment, possibly through an improved cardiac function. We aimed to evaluate the influence of these metabolic changes on cardiac function in patients with T2D. METHODS: In a randomized cross-over design, the SGLT2 inhibitor empagliflozin (E) was compared with insulin (I) treatment titrated to the same level of glycemic control in 17 patients with type 2 diabetes, BMI of > 28 kg/m2, C-peptide > 500 pM. Treatments lasted 5 weeks and were preceded by 3-week washouts (WO). At the end of treatments and washouts, cardiac diastolic function was determined with magnetic resonance imaging from left ventricle early peak-filling rate and left atrial passive emptying fraction (primary and key secondary endpoints); systolic function from left ventricle ejection fraction (secondary endpoint). Coupling between cardiac function and fatty acid concentrations, was studied on a separate day with a second scan after reduction of plasma fatty acids with acipimox. Data are Mean ± standard error. Between treatment difference (ΔT: E-I) and treatments effects (ΔE: E-WO or ΔI: I -WO) were evaluated using Students' t-test or Wilcoxon signed rank test as appropriate. RESULTS: Glucose concentrations were similar, fatty acids, ketone bodies and lipid oxidation increased while insulin concentrations decreased on empagliflozin compared with insulin treatment. Cardiac diastolic and systolic function were unchanged by either treatment. Acipimox decreased fatty acids with 35% at all visits, and this led to reduced cardiac diastolic (ΔT: -51 ± 22 ml/s (p < 0.05); ΔE: -33 ± 26 ml/s (ns); ΔI: 37 ± 26 (ns, p < 0.05 vs ΔE)) and systolic function (ΔT: -3 ± 1% (p < 0.05); ΔE: -3 ± 1% (p < 0.05): ΔI: 1 ± 2 (ns, ns vs ΔE)) under chronotropic stress during empagliflozin compared to insulin treatment. CONCLUSIONS: Despite significant metabolic differences, cardiac function did not differ on empagliflozin compared with insulin treatment. Impaired cardiac function during acipimox treatment, could suggest greater cardiac reliance on lipid metabolism for proper function during empagliflozin treatment in patients with type 2 diabetes. TRIAL REGISTRATION: EudraCT 2017-002101-35, August 2017.

Signs of Glucagon Resistance After a 2-Week Hypercaloric Diet Intervention.

CONTEXT: Hyperglucagonemia is observed in individuals with obesity and contributes to the hyperglycemia of patients with type 2 diabetes. Hyperglucagonemia may develop due to steatosis-induced hepatic glucagon resistance resulting in impaired hepatic amino acid turnover and ensuing elevations of circulating glucagonotropic amino acids. OBJECTIVE: We evaluated whether glucagon resistance could be induced in healthy individuals by a hypercaloric diet intervention designed to increase hepatic fat content. METHODS: We recruited 20 healthy male individuals to follow a hypercaloric diet and a sedentary lifestyle for 2 weeks. Amino acid concentrations in response to infusion of glucagon were assessed during a pancreatic clamp with somatostatin and basal insulin. The reversibility of any metabolic changes was assessed 8 weeks after the intervention. Hepatic steatosis was assessed by magnetic resonance spectroscopy. RESULTS: The intervention led to increased hepatic fat content (382% [206%; 705%], P < .01). Glucagon infusion led to a decrease in the concentration of total amino acids on all experimental days, but the percentage change in total amino acids was reduced (-2.5% ± 0.5% vs -0.2% ± 0.7%, P = .015) and the average slope of the decline in the total amino acid concentration was less steep (-2.0 ± 1.2 vs -1.2 ± 0.3 µM/min, P = .016) after the intervention compared to baseline. The changes were normalized at follow-up. CONCLUSION: Our results indicate that short-term unhealthy behavior, which increases hepatic fat content, causes a reversible resistance to the effect of glucagon on amino acid concentrations in healthy individuals, which may explain the hyperglucagonemia associated with obesity and diabetes.

Suboptimal Weight Loss 13 Years After Roux-en-Y Gastric Bypass Is Associated with Blunted Appetite Response.

PURPOSE: Bariatric surgery remains the most efficient treatment to achieve a sustained weight loss. However, a large proportion of patients experience suboptimal weight loss (SWL). The exact mechanisms involved remain to be fully elucidated, but the homeostatic appetite control system seems to be involved. The aim of this study was, therefore, to compare the plasma concentration of gastrointestinal hormones, and appetite ratings, between those experiencing SWL and optimal weight loss (OWL) after Roux-en-Y gastric bypass (RYGB). MATERIALS AND METHODS: Fifty participants from the Bariatric Surgery Observation Study (BAROBS) experiencing either SWL or OWL (< or ≥ 50% of excess weight loss (EWL), respectively) > 13 years post-RYGB were compared to 25 non-surgical controls. Plasma concentrations of acylated ghrelin (AG), total glucagon-like peptide-1 (GLP-1), total peptide YY (PYY), cholecystokinin (CCK), and subjective ratings of hunger, fullness, desire to eat (DTE), and prospective food consumption (PFC) were assessed in the fasting and postprandial (area under the curve (AUC)) states. RESULTS: Those experiencing OWL presented with higher basal AG and GLP-1 iAUC, and lower AG iAUC compared with SWL and controls. Additionally, both bariatric groups presented with higher PYY and CCK iAUC compared to controls. PFC tAUC was also lower in OWL compared to the SWL group. Total weight loss was positively correlated with GLP-1 tAUC and negatively correlated with fasting and tAUC DTE and PFC tAUC. CONCLUSIONS: SWL > 13 years post-RYGB is associated with lower basal ghrelin, as well as a weaker satiety response to a meal. Future studies should investigate the causality of these associations.

Altered glucagon and GLP-1 responses to oral glucose in children and adolescents with obesity and insulin resistance.

CONTEXT: Pediatric obesity is characterized by insulin resistance, yet it remains unclear whether insulin resistance contributes to abnormalities in glucagon and incretin secretion. OBJECTIVE: To examine whether fasting and stimulated glucagon, GLP-1, and GIP concentrations differ between children and adolescents with obesity and insulin resistance (OIR), obesity and normal insulin sensitivity (OIS), and controls with normal weight (NW). METHODS: 80 (34 boys) children and adolescents, aged 7-17 years with OIR (n=22), OIS (n=22), and NW (n=36) underwent an oral glucose tolerance test with measurements of serum insulin, plasma glucose, glucagon, total GLP-1, and total GIP. Homeostatic model assessment of insulin resistance (HOMA-IR), single point insulin sensitivity estimator (SPISE), Matsuda index, insulinogenic index (IGI), and oral disposition index (ODI) were calculated. RESULTS: Fasting concentrations of glucagon and GLP-1 were higher in the OIR-group, with no significant differences for GIP. The OIR-group had higher glucagon total area under the curve (tAUC0-120) and lower GLP-1 incremental AUC (iAUC0-120), with no significant differences for GIP iAUC0-120. Higher fasting glucagon was associated with higher HOMA-IR, lower Matsuda index, lower SPISE, higher IGI, and higher plasma alanine transaminase, whereas higher fasting GLP-1 was associated with higher HOMA-IR, lower Matsuda index, and lower ODI. Higher glucagon tAUC0-120 was associated lower SPISE and lower Matsuda index, whereas lower GLP-1 iAUC0-120 was associated with a higher HOMA-IR, lower Matsuda index, and lower ODI. CONCLUSIONS: The OIR-group had elevated fasting concentrations of glucagon and GLP-1, and higher glucagon, but lower GLP-1 responses during an OGTT compared to the OIS- and NW-groups. In contrast, the OIS-group had similar hormone responses to the NW-group.