Exercise-induced increase in muscle insulin sensitivity in men is amplified when assessed using a meal test.

AIMS/HYPOTHESIS: Exercise has a profound effect on insulin sensitivity in skeletal muscle. The euglycaemic-hyperinsulinaemic clamp (EHC) is the gold standard for assessment of insulin sensitivity but it does not reflect the hyperglycaemia that occurs after eating a meal. In previous EHC investigations, it has been shown that the interstitial glucose concentration in muscle is decreased to a larger extent in previously exercised muscle than in rested muscle. This suggests that previously exercised muscle may increase its glucose uptake more than rested muscle if glucose supply is increased by hyperglycaemia. Therefore, we hypothesised that the exercise-induced increase in muscle insulin sensitivity would appear greater after eating a meal than previously observed with the EHC. METHODS: Ten recreationally active men performed dynamic one-legged knee extensor exercise for 1 h. Following this, both femoral veins and one femoral artery were cannulated. Subsequently, 4 h after exercise, a solid meal followed by two liquid meals were ingested over 1 h and glucose uptake in the two legs was measured for 3 h. Muscle biopsies from both legs were obtained before the meal test and 90 min after the meal test was initiated. Data obtained in previous studies using the EHC (n=106 participants from 13 EHC studies) were used for comparison with the meal-test data obtained in this study. RESULTS: Plasma glucose and insulin peaked 45 min after initiation of the meal test. Following the meal test, leg glucose uptake and glucose clearance increased twice as much in the exercised leg than in the rested leg; this difference is twice as big as that observed in previous investigations using EHCs. Glucose uptake in the rested leg plateaued after 15 min, alongside elevated muscle glucose 6-phosphate levels, suggestive of compromised muscle glucose metabolism. In contrast, glucose uptake in the exercised leg plateaued 45 min after initiation of the meal test and there were no signs of compromised glucose metabolism. Phosphorylation of the TBC1 domain family member 4 (TBC1D4; p-TBC1D4Ser704) and glycogen synthase activity were greater in the exercised leg compared with the rested leg. Muscle interstitial glucose concentration increased with ingestion of meals, although it was 16% lower in the exercised leg than in the rested leg. CONCLUSIONS/INTERPRETATION: Hyperglycaemia after meal ingestion results in larger differences in muscle glucose uptake between rested and exercised muscle than previously observed during EHCs. These findings indicate that the ability of exercise to increase insulin-stimulated muscle glucose uptake is even greater when evaluated with a meal test than has previously been shown with EHCs.

Elucidating the glucose-lowering effect of the bile acid sequestrant sevelamer.

AIM: Bile acid sequestrants are cholesterol-lowering drugs, which also improve glycaemic control in people with type 2 diabetes. The mechanism behind the glucose-lowering effect is unknown but has been proposed to be mediated by increased glucagon-like peptide-1 (GLP-1) secretion. Here, we investigated the glucose-lowering effects of sevelamer including any contribution from GLP-1 in people with type 2 diabetes. MATERIALS AND METHODS: In a randomized, double-blind, placebo-controlled, crossover study, 15 people with type 2 diabetes on metformin monotherapy underwent two 17-day treatment periods with the bile acid sequestrant sevelamer and placebo, respectively, in a randomized order and with an interposed wash-out period of minimum 6 weeks. On days 15 and 17 of each treatment period, participants underwent experimental days with 4-h liquid meal tests and application of concomitant infusion of exendin(9-39)NH2 or saline. RESULTS: Compared with placebo, sevelamer improved insulin sensitivity (assessed by homeostatic model assessment of insulin resistance) and beta-cell sensitivity to glucose and lowered fasting and postprandial plasma glucose concentrations. In both treatment periods, exendin(9-39)NH2 increased postprandial glucose excursions compared with saline but without absolute or relative difference between the two treatment periods. In contrast, exendin(9-39)NH2 abolished the sevelamer-induced improvement in beta-cell glucose sensitivity. CONCLUSIONS: The bile acid sequestrant sevelamer improved insulin sensitivity and beta-cell sensitivity to glucose, but using the GLP-1 receptor antagonist exendin(9-39)NH2 we were not able to detect a GLP-1-mediated glucose-lowering effect of sevelamer in individuals with type 2 diabetes. Nevertheless, the sevelamer-induced improvement of beta-cell sensitivity to glucose was shown to be GLP-1-dependent.

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.

The effects of postprandial exercise and meal glycemic index on plasma glucose and glucoregulatory hormone responses after Roux-en-Y gastric bypass.

Postprandial hypoglycemia is a complication of Roux-en-Y gastric bypass (RYGB), but the effects of postprandial exercise and meal glycemic index (GI) on postprandial glucose and glucoregulatory hormone responses are unknown. Ten RYGB-operated and 10 age and weight-matched unoperated women completed four test days in random order ingesting mixed meals with high GI (HGI, GI = 93) or low GI (LGI, GI = 54), but matched on energy and macronutrient content. Ten minutes after meal completion, participants rested or cycled for 30 min at 70% of maximum oxygen uptake (V̇o2max). Blood was collected for 4 h. Postprandial exercise did not lower plasma nadir glucose in RYGB after HGI (HGI/rest 3.7 ± 0.5 vs. HGI/Ex 4.1 ± 0.4 mmol/L, P = 0.070). Replacing HGI with LGI meals raised glucose nadir in RYGB (LGI/rest 4.1 ± 0.5 mmol/L, P = 0.034) and reduced glucose excursions (Δpeak-nadir) but less so in RYGB (-14% [95% CI: -27; -1]) compared with controls (-33% [-51; -14]). Insulin responses mirrored glucose concentrations. Glucagon-like peptide 1 (GLP-1) responses were greater in RYGB versus controls, and higher with HGI versus LGI. Glucose-dependent insulinotropic polypeptide (GIP) responses were greater after HGI versus LGI in both groups. Postexercise glucagon responses were lower in RYGB than controls, and noradrenaline responses tended to be lower in RYGB, whereas adrenaline responses were similar between groups. In conclusion, moderate intensity cycling shortly after meal intake did not increase the risk of postprandial hypoglycemia after RYGB. The low GI meal increased nadir glucose and reduced glucose excursions compared with the high GI meal. RYGB participants had lower postexercise glucagon responses compared with controls.NEW & NOTEWORTHY We investigate the effect of moderate exercise after a high or a low glycemic index meal on nadir glucose and glucoregulatory hormones in gastric bypass-operated individuals and in matched unoperated controls. Cycling shortly after meal intake did not increase the risk of hypoglycemia in operated individuals. The low glycemic index meal increased glucose nadir and reduced excursions compared with the high glycemic index meal. Operated individuals had lower postexercise glucagon responses compared with controls.

Primary weight loss failure after Roux-en-Y gastric bypass is characterized by impaired gut-hormone mediated regulation of food intake.

BACKGROUND/OBJECTIVES: After Roux-en-Y gastric bypass (RYGB) a subset of patients never obtain excess BMI loss (EBMIL) > 50% and are categorized as having primary weight loss (WL) failure. We hypothesized that postprandial concentrations of glucagon-like peptide 1 (GLP-1) and peptide YY (PYY) would be lower in patients with primary WL failure compared with patients with successfully maintained WL. Furthermore, that inhibition of gut hormone secretions would increase ad libitum food intake less in patients with primary WL failure. SUBJECTS/METHODS: Twenty women with primary WL failure (LowEBMIL < 50%) were individually matched to twenty women with successful WL (HighEBMIL > 60%) on age, preoperative BMI and time from RYGB. On separate days performed in a random order, patient-blinded subcutaneous injections of octreotide or saline (placebo) were followed by a fixed breakfast and an ad libitum lunch with blood sampling for appetite regulating hormones and Visual-Analogue-Scale (VAS)-scoring of hunger/satiety. Furthermore, participants underwent gene variant analysis for GLP-1, PYY and their receptors, indirect calorimetry, dual-energy X-ray absorptiometry (DXA)-scans, 4-days at-home food registration and 14-days step counting. RESULTS: On placebo days, postprandial GLP-1, PYY and cholecystokinin (CCK) concentrations were similar between groups after breakfast. Fasting ghrelin was lower in LowEBMIL, but the postprandial suppression was similar. LowEBMIL had lower satiety VAS-scores and less suppression of hunger VAS-scores. Gene variants did not differ between groups. Octreotide diminished GLP-1, PYY, CCK and ghrelin concentrations in both groups. Octreotide did not affect ad libitum food intake in LowEBMIL (-1% [-13, 12], mean [95%CI]), while food intake increased in HighEBMIL (+23% [2,44]). CONCLUSIONS: Primary WL failure after RYGB was not characterized by impaired secretions of appetite regulating gut hormones. Interestingly, inhibition of gut hormone secretions with octreotide only increased food intake in patients with successful WL post-RYGB. Thus, an impaired central anorectic response to gut hormones may contribute to primary WL failure after RYGB.

Effects of topical corticosteroid versus tacrolimus on insulin sensitivity and bone homeostasis in adults with atopic dermatitis-A randomized controlled study.

INTRODUCTION: Topical corticosteroids (TCS), used to treat atopic dermatitis (AD), have been associated with type 2 diabetes and osteoporosis in epidemiological studies, possibly explained by systemic absorption. OBJECTIVES: We examined whether intensive daily whole-body TCS treatment over 2 weeks followed by twice weekly application for 4 weeks could elicit insulin resistance and increase bone resorption in adults with AD. METHODS: A randomized parallel-group double-blind double-dummy non-corticosteroid-based active comparator study design was completed in Copenhagen, Denmark. Thirty-six non-obese, non-diabetic adults with moderate-to-severe AD were randomized to whole-body treatment with betamethasone 17-valerate 0.1% plus a vehicle once daily or tacrolimus 0.1% twice daily after washout. Insulin sensitivity assessed by the hyperinsulinemic-euglycemic clamp combined with tracer infusions and biomarkers of bone formation (P1NP) and resorption (CTX) were evaluated at baseline, after 2 weeks of daily treatment and after further 4 weeks of twice-weekly maintenance treatment. RESULTS: AD severity improved with both treatments and systemic inflammation was reduced. After 2 weeks, we observed similar increase in peripheral insulin sensitivity with use of betamethasone (n = 18) and tacrolimus (n = 18). Bone resorption biomarker, CTX, was unchanged, while bone formation marker, P1NP, decreased after betamethasone treatment after both 2 and 6 weeks but remained unchanged in the tacrolimus arm. CONCLUSIONS: Whole-body treatment with TCS leads to systemic exposure but appears not to compromise glucose metabolism during short-term use, which may be a result of reduced systemic inflammatory activity. The negative impact on bone formation could be regarded an adverse effect of TCS.

A randomized, double-blind, crossover study of the effect of the fluoroquinolone moxifloxacin on glucose levels and insulin sensitivity in young men and women.

AIM: The voltage-gated potassium channel Kv 11.1 is important for repolarizing the membrane potential in excitable cells such as myocytes, pancreatic α- and ß-cells. Moxifloxacin blocks the Kv 11.1 channel and increases the risk of hypoglycaemia in patients with diabetes. We investigated glucose regulation and secretion of glucoregulatory hormones in young people with and without moxifloxacin, a drug known to block the Kv 11.1 channel. MATERIALS AND METHODS: The effect of moxifloxacin (800 mg/day for 4 days) or placebo on glucose regulation was assessed in a randomized, double-blind, crossover study of young men and women (age 20-40 years and body mass index 18.5-27.5 kg/m2 ) without chronic disease, using 6-h oral glucose tolerance tests and continuous glucose monitoring. RESULTS: Thirty-eight participants completed the study. Moxifloxacin prolonged the QTcF interval and increased heart rate. Hypoglycaemia was more frequently observed with moxifloxacin, both during the 8 days of continuous glucose monitoring and during the oral glucose tolerance tests. Hypoglycaemia questionnaire scores were higher after intake of moxifloxacin. Moxifloxacin reduced the early plasma-glucose response (AUC0-30 min ) by 7% (95% CI: -9% to -4%, p < .01), and overall insulin response (AUC0-360 min ) decreased by 18% (95% CI: -24% to -11%, p < .01) and plasma glucagon increased by 17% (95% CI: 4%-33%, p = .03). Insulin sensitivity calculated as the Matsuda index increased by 11%, and MISI, an index of muscle insulin sensitivity, increased by 34%. CONCLUSIONS: In young men and women, moxifloxacin, a drug known to block the Kv 11.1 channel, increased QT interval, decreased glucose levels and was associated with increased muscle insulin sensitivity and more frequent episodes of hypoglycaemia.

Liraglutide changes postprandial responses of gut hormones involved in the regulation of gallbladder motility.

AIM: Liraglutide treatment is associated with gallbladder-related disorders and has been shown to delay postprandial gallbladder refilling. The gut hormones cholecystokinin (CCK), fibroblast growth factor 19 (FGF19) and glucagon-like peptide 2 (GLP-2), are known to regulate gallbladder motility and may be implicated in gallbladder-related disorders associated with liraglutide treatment. MATERIALS AND METHODS: In a double-blind, 12-week trial, 52 participants [50% male, age 47.6 ± 10.0 years, body mass index 32.6 ± 3.4 kg/m2 (mean ± standard deviation)] with obesity were randomized 1:1 to once-daily subcutaneous liraglutide (escalated from 0.6 mg to 3.0 mg once-daily) or placebo. During liquid meal tests performed at baseline, after the first dose and following 12 weeks of treatment, we evaluated postprandial gallbladder dynamics and plasma responses of CCK, FGF19 and GLP-2. RESULTS: Liraglutide reduced postprandial FGF19 after the first dose [area under the curve (AUC)0-240 min 24.8 vs. 48.0 min × ng/ml, treatment ratio (TR) (95% confidence interval) 0.52 (0.39; 0.69)] and following 12 weeks of treatment [AUC0-240 min 33.7 vs. 48.5 ng/ml × min, TR 0.69 (0.52; 0.93)]. Liraglutide also reduced postprandial GLP-2 responses (AUC0-240 min 3650 vs. 4894 min × pmol/L, TR 0.75 (0.62; 0.90)] following the first dose as well as after 12 weeks [AUC0-240 min 3760 vs. 4882 min × pmol/L, TR 0.77 (0.60; 0.99)]. Liraglutide increased postprandial responses of CCK after the first dose [AUC0-240 min 762 vs. 670 min × pmol/L; TR 1.14 (0.97; 1.33)] and following 12 weeks of treatment [AUC0-240 min 873 vs. 628 min × pmol/L; TR 1.39 (1.12; 1.73)]. CONCLUSION: Compared with placebo, treatment with liraglutide decreased postprandial FGF19 and GLP-2 concentrations and increased postprandial CCK concentrations, which may explain the delayed postprandial gallbladder refilling observed in individuals with obesity treated with liraglutide.

Preanalytical impact on the accuracy of measurements of glucagon, GLP-1 and GIP in clinical trials.

BACKGROUND: Plasma concentrations of glucagon, GLP-1 and GIP are reported in numerous clinical trials as outcome measures but preanalytical guidelines are lacking. We addressed the impact of commonly used blood containers in metabolic research on measurements of glucagon, GLP-1 and GIP in humans. METHODS: Seventeen overweight individuals were subjected to an overnight fast followed by an intravenous infusion of amino acids to stimulate hormonal secretion. Blood was sampled into five containers: EDTA-coated tubes supplemented with DMSO (control), a neprilysin inhibitor, aprotinin (a kallikrein inhibitor) or a DPP-4 inhibitor, and P800 tubes. Plasma was kept on ice before and after centrifugation and stored at -80 Celsius until batch analysis using validated sandwich ELISAs or radioimmunoassays (RIA). RESULTS: Measures of fasting plasma glucagon did not depend on sampling containers, whether measured by ELISA or RIA. Amino acid-induced hyperglucagonemia was numerically higher when blood was collected into P800 tubes or tubes with aprotinin. The use of p800 tubes resulted in higher concentrations of GLP-1 by RIA compared to control tubes but not for measurements with sandwich ELISA. Plasma concentrations of GIP measured by ELISA were higher in control tubes and negatively affected by P800 and the addition of aprotinin. CONCLUSIONS: The choice of blood containers impacts on measurements of plasma concentrations of glucagon, GLP-1 and GIP, and based on this study, we recommend using EDTA-coated tubes without protease inhibitors or P800 tubes for measurements of glucagon, GLP-1 and GIP in clinical trials.

Duodenal Anaerobutyricum soehngenii infusion stimulates GLP-1 production, ameliorates glycaemic control and beneficially shapes the duodenal transcriptome in metabolic syndrome subjects: a randomised double-blind placebo-controlled cross-over study.

OBJECTIVE: Although gut dysbiosis is increasingly recognised as a pathophysiological component of metabolic syndrome (MetS), the role and mode of action of specific gut microbes in metabolic health remain elusive. Previously, we identified the commensal butyrogenic Anaerobutyricum soehngenii to be associated with improved insulin sensitivity in subjects with MetS. In this proof-of-concept study, we investigated the potential therapeutic effects of A. soehngenii L2-7 on systemic metabolic responses and duodenal transcriptome profiles in individuals with MetS. DESIGN: In this randomised double-blind placebo-controlled cross-over study, 12 male subjects with MetS received duodenal infusions of A. soehngenii/ placebo and underwent duodenal biopsies, mixed meal tests (6 hours postinfusion) and 24-hour continuous glucose monitoring. RESULTS: A. soehngenii treatment provoked a markedly increased postprandial excursion of the insulinotropic hormone glucagon-like peptide 1 (GLP-1) and an elevation of plasma secondary bile acids, which were positively associated with GLP-1 levels. Moreover, A. soehngenii treatment robustly shaped the duodenal expression of 73 genes, with the highest fold induction in the expression of regenerating islet-protein 1B (REG1B)-encoding gene. Strikingly, duodenal REG1B expression positively correlated with GLP-1 levels and negatively correlated with peripheral glucose variability, which was significantly diminished in the 24 hours following A. soehngenii intake. Mechanistically, Reg1B expression is induced upon sensing butyrate or bacterial peptidoglycan. Importantly, A. soehngenii duodenal administration was safe and well tolerated. CONCLUSIONS: A single dose of A. soehngenii improves peripheral glycaemic control within 24 hours; it specifically stimulates intestinal GLP-1 production and REG1B expression. Further studies are needed to delineate the specific pathways involved in REG1B induction and function in insulin sensitivity. TRIAL REGISTRATION NUMBER: NTR-NL6630.

Dietary carbohydrate restriction augments weight loss-induced improvements in glycaemic control and liver fat in individuals with type 2 diabetes: a randomised controlled trial.

AIMS/HYPOTHESIS: Lifestyle modification and weight loss are cornerstones of type 2 diabetes management. However, carbohydrate restriction may have weight-independent beneficial effects on glycaemic control. This has been difficult to demonstrate because low-carbohydrate diets readily decrease body weight. We hypothesised that carbohydrate restriction enhances the beneficial metabolic effects of weight loss in type 2 diabetes. METHODS: This open-label, parallel RCT included adults with type 2 diabetes, HbA1c 48-97 mmol/mol (6.5-11%), BMI >25 kg/m2, eGFR >30 ml min-1 [1.73 m]-2 and glucose-lowering therapy restricted to metformin or dipeptidyl peptidase-4 inhibitors. Participants were randomised by a third party and assigned to 6 weeks of energy restriction (all foods were provided) aiming at ~6% weight loss with either a carbohydrate-reduced high-protein diet (CRHP, percentage of total energy intake [E%]: CH30/P30/F40) or a conventional diabetes diet (CD, E%: CH50/P17/F33). Fasting blood samples, continuous glucose monitoring and magnetic resonance spectroscopy were used to assess glycaemic control, lipid metabolism and intrahepatic fat. Change in HbA1c was the primary outcome; changes in circulating and intrahepatic triacylglycerol were secondary outcomes. Data were collected at Copenhagen University Hospital (Bispebjerg and Herlev). RESULTS: Seventy-two adults (CD 36, CRHP 36, all white, 38 male sex) with type 2 diabetes (mean duration 8 years, mean HbA1c 57 mmol/mol [7.4%]) and mean BMI of 33 kg/m2 were enrolled, of which 67 (CD 33, CRHP 34) completed the study. Body weight decreased by 5.8 kg (5.9%) in both groups after 6 weeks. Compared with the CD diet, the CRHP diet further reduced HbA1c (mean [95% CI] -1.9 [-3.5, -0.3] mmol/mol [-0.18 (-0.32, -0.03)%], p = 0.018) and diurnal mean glucose (mean [95% CI] -0.8 [-1.2, -0.4] mmol/l, p < 0.001), stabilised glucose excursions by reducing glucose CV (mean [95% CI] -4.1 [-5.9, -2.2]%, p < 0.001), and augmented the reductions in fasting triacylglycerol concentration (by mean [95% CI] -18 [-29, -6]%, p < 0.01) and liver fat content (by mean [95% CI] -26 [-45, 0]%, p = 0.051). However, pancreatic fat content was decreased to a lesser extent by the CRHP than the CD diet (mean [95% CI] 33 [7, 65]%, p = 0.010). Fasting glucose, insulin, HOMA2-IR and cholesterol concentrations (total, LDL and HDL) were reduced significantly and similarly by both diets. CONCLUSIONS/INTERPRETATION: Moderate carbohydrate restriction for 6 weeks modestly improved glycaemic control, and decreased circulating and intrahepatic triacylglycerol levels beyond the effects of weight loss itself compared with a CD diet in individuals with type 2 diabetes. Concurrent differences in protein and fat intakes, and the quality of dietary macronutrients, may have contributed to these results and should be explored in future studies. TRIAL REGISTRATION: ClinicalTrials.gov NCT03814694. FUNDING: The study was funded by Arla Foods amba, The Danish Dairy Research Foundation, and Copenhagen University Hospital Bispebjerg Frederiksberg.

Opposing roles of the entero-pancreatic hormone urocortin-3 in glucose metabolism in rats.

AIM/HYPOTHESIS: Urocortin-3 (UCN3) is a glucoregulatory peptide produced in the gut and pancreatic islets. The aim of this study was to clarify the acute effects of UCN3 on glucose regulation following an oral glucose challenge and to investigate the mechanisms involved. METHODS: We studied the effect of UCN3 on blood glucose, gastric emptying, glucose absorption and secretion of gut and pancreatic hormones in male rats. To supplement these physiological studies, we mapped the expression of UCN3 and the UCN3-sensitive receptor, type 2 corticotropin-releasing factor receptor (CRHR2), by means of fluorescence in situ hybridisation and by gene expression analysis. RESULTS: In rats, s.c. administration of UCN3 strongly inhibited gastric emptying and glucose absorption after oral administration of glucose. Direct inhibition of gastrointestinal motility may be responsible because UCN3's cognate receptor, CRHR2, was detected in gastric submucosal plexus and in interstitial cells of Cajal. Despite inhibited glucose absorption, post-challenge blood glucose levels matched those of rats given vehicle in the low-dose UCN3 group, because UCN3 concomitantly inhibited insulin secretion. Higher UCN3 doses did not further inhibit gastric emptying, but the insulin inhibition progressed resulting in elevated post-challenge glucose and lipolysis. Incretin hormones and somatostatin (SST) secretion from isolated perfused rat small intestine was unaffected by UCN3 infusion; however, UCN3 infusion stimulated secretion of somatostatin from delta cells in the isolated perfused rat pancreas which, unlike alpha cells and beta cells, expressed Crhr2. Conversely, acute antagonism of CRHR2 signalling increased insulin secretion by reducing SST signalling. Consistent with these observations, acute drug-induced inhibition of CRHR2 signalling improved glucose tolerance in rats to a similar degree as administration of glucagon-like peptide-1. UCN3 also powerfully inhibited glucagon secretion from isolated perfused rat pancreas (perfused with 3.5 mmol/l glucose) in a SST-dependent manner, suggesting that UCN3 may be involved in glucose-induced inhibition of glucagon secretion. CONCLUSIONS/INTERPRETATION: Our combined data indicate that UCN3 is an important glucoregulatory hormone that acts through regulation of gastrointestinal and pancreatic functions.

The Role of D-allulose and Erythritol on the Activity of the Gut Sweet Taste Receptor and Gastrointestinal Satiation Hormone Release in Humans: A Randomized, Controlled Trial.

BACKGROUND: Glucose induces the release of gastrointestinal (GI) satiation hormones, such as glucagon-like peptide 1 (GLP-1) and peptide tyrosine tyrosine (PYY), in part via the activation of the gut sweet taste receptor (T1R2/T1R3). OBJECTIVES: The primary objective was to investigate the importance of T1R2/T1R3 for the release of cholecystokinin (CCK), GLP-1, and PYY in response to D-allulose and erythritol by assessing the effect of the T1R2/T1R3 antagonist lactisole on these responses and as secondary objectives to study the effect of the T1R2/T1R3 blockade on gastric emptying, appetite-related sensations, and GI symptoms. METHODS: In this randomized, controlled, double-blind, crossover study, 18 participants (5 men) with a mean ± SD BMI (in kg/m2) of 21.9 ± 1.7 and aged 24 ± 4 y received an intragastric administration of 25 g D-allulose, 50 g erythritol, or tap water, with or without 450 parts per million (ppm) lactisole, respectively, in 6 different sessions. 13C-sodium acetate was added to all solutions to determine gastric emptying. At fixed time intervals, blood and breath samples were collected, and appetite-related sensations and GI symptoms were assessed. Data were analyzed with linear mixed-model analysis. RESULTS: D-allulose and erythritol induced a significant release of CCK, GLP-1, and PYY compared with tap water (all PHolm < 0.0001, dz >1). Lactisole did not affect the D-allulose- and erythritol-induced release of CCK, GLP-1, and PYY (all PHolm > 0.1). Erythritol significantly delayed gastric emptying, increased fullness, and decreased prospective food consumption compared with tap water (PHolm = 0.0002, dz = -1.05; PHolm = 0.0190, dz = 0.69; and PHolm = 0.0442, dz = -0.62, respectively). CONCLUSIONS: D-allulose and erythritol stimulate the secretion of GI satiation hormones in humans. Lactisole had no effect on CCK, GLP-1, and PYY release, indicating that D-allulose- and erythritol-induced GI satiation hormone release is not mediated via T1R2/T1R3 in the gut.

GIP and GLP-2 together improve bone turnover in humans supporting GIPR-GLP-2R co-agonists as future osteoporosis treatment.

The intestinal hormones glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-2 (GLP-2) are key regulators of postprandial bone turnover in humans. We hypothesized that GIP and GLP-2 co-administration would provide stronger effect on bone turnover than administration of the hormones separately, and tested this using subcutaneous injections of GIP and GLP-2 alone or in combination in humans. Guided by these findings, we designed series of GIPR-GLP-2R co-agonists as template for new osteoporosis treatment. The clinical experiment was a randomized cross-over design including 10 healthy men administered subcutaneous injections of GIP and GLP-2 alone or in combination. The GIPR-GLP-2R co-agonists were characterized in terms of binding and activation profiles on human and rodent GIP and GLP-2 receptors, and their pharmacokinetic (PK) profiles were improved by dipeptidyl peptidase-4 protection and site-directed lipidation. Co-administration of GIP and GLP-2 in humans resulted in an additive reduction in bone resorption superior to each hormone individually. The GIPR-GLP-2R co-agonists, designed by combining regions of importance for cognate receptor activation, obtained similar efficacies as the two native hormones and nanomolar potencies on both human receptors. The PK-improved co-agonists maintained receptor activity along with their prolonged half-lives. Finally, we found that the GIPR-GLP-2R co-agonists optimized toward the human receptors for bone remodeling are not feasible for use in rodent models. The successful development of potent and efficacious GIPR-GLP-2R co-agonists, combined with the improved effect on bone metabolism in humans by co-administration, support these co-agonists as a future osteoporosis treatment.

Effects of short-acting exenatide added three times daily to insulin therapy on bone metabolism in type 1 diabetes.

AIM: To evaluate the efficacy of the short-acting glucagon-like peptide-1 receptor agonist, exenatide, added to insulin therapy in type 1 diabetes on bone mineral density and bone turnover markers. MATERIALS AND METHODS: In a randomized, double-blinded, parallel-group trial, 108 individuals with type 1 diabetes aged 18 years or older on basal-bolus therapy with HbA1c 59-88 mmol/mol (7.5%-10.0%) and body mass index of more than 22.0 kg/m2 were randomized (1:1) to preprandial subcutaneous injection of 10 µg exenatide (Byetta) before breakfast, lunch, and dinner over 26 weeks as add-on treatment to insulin therapy. RESULTS: Exenatide elicited a body weight reduction of 4.4 kg compared with placebo, but no between-group differences in bone mineral density, as assessed by whole-body, hip, lumbar, and forearm dual-energy X-ray absorptiometry following 26 weeks of treatment, were observed. Fasting plasma levels of C-terminal telopeptides of type I collagen, a marker of bone resorption, and amino-terminal propeptide of type I procollagen, a marker of bone formation, were unchanged by exenatide compared with placebo after 26 weeks. CONCLUSIONS: Despite an exenatide-induced body weight reduction, no changes in bone metabolism were observed with exenatide added to insulin therapy in type 1 diabetes after 26 weeks.

Hypoglycaemia and rebound hyperglycaemia increase left ventricular systolic function in patients with type 1 diabetes.

AIM: To investigate echocardiographic changes during acute hypoglycaemia followed by recovery to hyperglycaemia or euglycaemia in patients with type 1 diabetes. MATERIALS AND METHODS: In a randomized crossover study, 24 patients with type 1 diabetes took part in two experimental study days, consisting of a hyperinsulinaemic-euglycaemic phase (5.0-8.0 mmol/L) for 45 minutes followed by a hyperinsulinemic-hypoglycaemic phase (2.5 mmol/L) for 60 minutes, and a recovery phase in either hyperglycaemia (20 mmol/L) or euglycaemia (5.0-8.0 mmol/L) for 60 minutes. Cardiac function was evaluated with echocardiography during each phase. RESULTS: Acute hypoglycaemia increased all markers of left ventricular (LV) systolic function, including LV ejection fraction (LVEF), global longitudinal strain (GLS), GLS rate and peak systolic velocity of mitral annular longitudinal movement (s'; P < 0.001 for all). During the recovery phases, all markers of LV systolic function were increased during hyperglycaemia (P < 0.01 for all), and LVEF and GLS remained increased during euglycaemia (P = 0.0116 and P = 0.0092, respectively). The increment in LVEF during the recovery phase was greater during hyperglycaemia than euglycaemia (P = 0.0046). CONCLUSIONS: Hypoglycaemia, recent hypoglycaemia, and overcorrection of hypoglycaemia to rebound hyperglycaemia increased LV systolic function in type 1 diabetes and may imply consideration of plasma glucose when evaluating LV function in patients with type 1 diabetes. An increase in LV systolic function may cause increased strain on the heart and partly explain the link between hypoglycaemia, high glycaemic variability and cardiovascular disease.

Postprandial renal haemodynamic effects of the dipeptidyl peptidase-4 inhibitor linagliptin versus the sulphonylurea glimepiride in adults with type 2 diabetes (RENALIS): A predefined substudy of a randomized, double-blind trial.

AIM: To determine the effect of the dipeptidyl peptidase-4 inhibitor linagliptin on postprandial glomerular hyperfiltration compared with the sulphonylurea glimepiride in adults with type 2 diabetes (T2D). MATERIALS AND METHODS: In this predefined substudy within a randomized, double-blind, parallel-group, intervention trial, overweight people with T2D without renal impairment were treated with once-daily linagliptin 5 mg (N = 10) or glimepiride 1 mg (N = 13) as an add-on to metformin for 8 weeks. After a standardized liquid protein-rich meal, the glomerular filtration rate (GFR) and effective renal plasma flow were determined by inulin and para-aminohippuric acid clearance, respectively, based on timed urine sampling. Intrarenal haemodynamics were estimated using the Gomez equations. Glucoregulatory/vasoactive hormones, urinary pH and fractional excretions (FE) of sodium, potassium and urea were measured. RESULTS: Compared with glimepiride, linagliptin increased the postprandial filtration fraction (FF; mean difference 2.1%-point; P = .016) and estimated glomerular hydraulic pressure (mean difference 3.0 mmHg; P = .050), and tended to increase GFR (P = .08) and estimated efferent renal arteriolar resistance (RE ; P = .08) from baseline to week 8. No differences in FE were noted. Glimepiride reduced HbA1c more than linagliptin (mean difference -0.40%; P = .004), without between-group differences in time-averaged postprandial glucose levels. In the linagliptin group, change in FF correlated with change in mean arterial pressure (R = 0.807; P = .009) and time-averaged mean glucagon (R = 0.782; P = .008), but not with changes in glucose, insulin, intact glucagon-like peptide-1, renin or FENa . Change in glucagon was associated with change in RE (R = 0.830; P = .003). CONCLUSIONS: In contrast to our hypothesis, compared with glimepiride, linagliptin does not reduce postprandial hyperfiltration, yet appears to increase FF after meal ingestion by increasing blood pressure or RE .

Segmental reversal of the distal small intestine in a short bowel syndrome model in piglets showed detrimental effect on weight gain.

BACKGROUND: To investigate the effects of a reversed segment of the distal small intestine to improve weight gain in an experimental short bowel syndrome (SBS) model in piglets. METHODS: Twenty-four piglets underwent resection of 70% of the distal small intestine. In half of the animals a conventional anastomosis was performed, and in the other half, the distal 25 cm of the remnant jejunum was reversed before the intestinal continuity was recreated. Weight was measured daily until day 28, where the animals were euthanized. Glucagon-Like Peptide-2 (GLP-2) and Glucose-dependent Insulinotropic Peptide (GIP) was measured pre- and postoperatively at day 28. RESULTS: The group with reversal of small intestine had a significant lower weight gain at 5.26 ± 3.39 kg (mean ± SD) compared to the control group with 11.14 ± 3.83 kg (p < 0.05). In the control group greater villus height and crypt depth was found distally, and greater muscular thickness was found proximally in the intervention group. GLP-2 and GIP levels increased significantly in the control group. CONCLUSIONS: Treatment of short bowel syndrome with a reversed jejunal segment of 25 cm had a detrimental effect on the weight gain.

Fortifying a meal with oyster mushroom powder beneficially affects postprandial glucagon-like peptide-1, non-esterified free fatty acids and hunger sensation in adults with impaired glucose tolerance: a double-blind randomized controlled crossover trial.

PURPOSE: Impaired glucose tolerance (IGT) is a pathophysiological condition characterized by insulin resistance with known metabolic consequences such as postprandial hyperglycemia and hypertriglyceridemia. We hypothesized that fortifying a meal with mushrooms rich in ß-glucans may diminish glucose and triglyceride responses by improving postprandial gastrointestinal hormone release. METHODS: In a randomized controlled crossover study, 22 subjects with IGT ingested a meal either enriched with 20 g powder (8.1 g ß-glucans) of oven-dried Pleurotus ostreatus (enriched meal, EN) or without enrichment (control meal, CON). Blood was collected before and repeatedly within 4 h after the meal to determine AUC of glucose (primary outcome), insulin, triglycerides, non-esterified free fatty acids (NEFAs), glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP) and ghrelin. Appetite sensations (hunger, satiety, fullness, and desire to eat) were assessed before and after meal consumption by visual analog scales. RESULTS: Postprandial glucose, insulin, triglycerides, GIP and ghrelin concentrations as well as the corresponding AUCs did not differ between EN and CON. NEFAs-AUC was 14% lower (P = 0.026) and GLP-1-AUC 17% higher (P = 0.001) after EN compared to CON. Appetite ratings did not differ between treatments, except for hunger (AUC 22% lower after EN vs. CON; P = 0.031). CONCLUSION: The observed immediate postprandial metabolic changes indicate that an easily manageable fortification of a single meal with powder from dried oyster mushrooms as ß-glucan source may improve postprandial metabolism. If the effect is preserved long term, this measure can diminish the risk for further development of overweight/obesity and type 2 diabetes in subjects with IGT. CLINICAL TRIAL REGISTRATION: German Clinical Trial Register on 09/08/2018; trial-ID: DRKS00015244.

The effect of 6-day subcutaneous glucose-dependent insulinotropic polypeptide infusion on time in glycaemic range in patients with type 1 diabetes: a randomised, double-blind, placebo-controlled crossover trial.

AIMS/HYPOTHESIS: Type 1 diabetes is characterised by reduced glucagon response to hypoglycaemia, increasing the risk of insulin treatment-associated hypoglycaemia known to hamper glycaemic control. We previously reported a glucagonotropic effect of exogenous glucose-dependent insulinotropic polypeptide (GIP) during insulin-induced hypoglycaemia in individuals with type 1 diabetes. Here we investigate the effect of a 6-day s.c. GIP infusion on time in glycaemic range as assessed by continuous glucose monitoring (CGM) in individuals with type 1 diabetes. METHODS: In a randomised, placebo-controlled, double-blind crossover study, time in glycaemic range (assessed by double-blinded CGM) was evaluated in 20 men with type 1 diabetes (18-75 years, stable insulin treatment ≥3 months, diabetes duration 2-15 years, fasting plasma C-peptide below 200 pmol/l, BMI 20-27 kg/m2, HbA1c <69 mmol/mol [8.5%]) during two × 6 days of continuous s.c. GIP (6 pmol kg-1 min-1) and placebo (saline [154 mmol/l NaCl]) infusion, respectively, with an interposed 7-day washout period. The primary outcome was glycaemic time below range, time in range and time above range. RESULTS: There were no significant differences in time below range (<3.9 mmol/l, p = 0.53) or above range (>10 mmol/l, p = 0.32) during night-time or daytime, in mean glucose, or in hypoglycaemic events as assessed by CGM. GIP altered neither self-reported hypoglycaemia nor safety measures. Compared with placebo, GIP significantly increased time in tight range (3.9-7.8 mmol/l) during daytime (06:00-23:59 hours) by [mean ± SEM] 11.2 ± 5.1% [95% CI 0.41, 21.9] (p = 0.02). CONCLUSIONS/INTERPRETATION: Six-day s.c. GIP infusion in men with type 1 diabetes did not procure convincing effect on overall time in range, but increased time in tight glycaemic range during daytime by ~2 h per day. TRIAL REGISTRATION: ClinicalTrials.gov NCT03734718. FUNDING: The study was funded by grants from The Leona M. and Harry B. Helmsley Charitable Trust and Aase og Ejnar Danielsens Fond.