AgRP Neurons Control Systemic Insulin Sensitivity via Myostatin Expression in Brown Adipose Tissue.

Activation of Agouti-related peptide (AgRP) neurons potently promotes feeding, and chronically altering their activity also affects peripheral glucose homeostasis. We demonstrate that acute activation of AgRP neurons causes insulin resistance through impairment of insulin-stimulated glucose uptake into brown adipose tissue (BAT). AgRP neuron activation acutely reprograms gene expression in BAT toward a myogenic signature, including increased expression of myostatin. Interference with myostatin activity improves insulin sensitivity that was impaired by AgRP neurons activation. Optogenetic circuitry mapping reveals that feeding and insulin sensitivity are controlled by both distinct and overlapping projections. Stimulation of AgRP → LHA projections impairs insulin sensitivity and promotes feeding while activation of AgRP → anterior bed nucleus of the stria terminalis (aBNST)vl projections, distinct from AgRP → aBNSTdm projections controlling feeding, mediate the effect of AgRP neuron activation on BAT-myostatin expression and insulin sensitivity. Collectively, our results suggest that AgRP neurons in mice induce not only eating, but also insulin resistance by stimulating expression of muscle-related genes in BAT, revealing a mechanism by which these neurons rapidly coordinate hunger states with glucose homeostasis.

Postprandial macrophage-derived IL-1ß stimulates insulin, and both synergistically promote glucose disposal and inflammation.

The deleterious effect of chronic activation of the IL-1ß system on type 2 diabetes and other metabolic diseases is well documented. However, a possible physiological role for IL-1ß in glucose metabolism has remained unexplored. Here we found that feeding induced a physiological increase in the number of peritoneal macrophages that secreted IL-1ß, in a glucose-dependent manner. Subsequently, IL-1ß contributed to the postprandial stimulation of insulin secretion. Accordingly, lack of endogenous IL-1ß signaling in mice during refeeding and obesity diminished the concentration of insulin in plasma. IL-1ß and insulin increased the uptake of glucose into macrophages, and insulin reinforced a pro-inflammatory pattern via the insulin receptor, glucose metabolism, production of reactive oxygen species, and secretion of IL-1ß mediated by the NLRP3 inflammasome. Postprandial inflammation might be limited by normalization of glycemia, since it was prevented by inhibition of the sodium-glucose cotransporter SGLT2. Our findings identify a physiological role for IL-1ß and insulin in the regulation of both metabolism and immunity.

Weight loss and treatment patterns in a real-world population of adults receiving liraglutide 3.0 mg for weight management in routine clinical practice in Switzerland (ADDRESS study).

AIM: To assess weight loss associated with liraglutide 3.0 mg treatment in individuals with obesity (body mass index [BMI] ≥30 kg/m2 ) or overweight (BMI > 27 to <30 kg/m2 ) in a reimbursed, real-world setting in Switzerland. MATERIALS AND METHODS: ADDRESS was a non-comparative, multicentre, retrospective exposure cohort study in Switzerland, examining weight loss in individuals with obesity or overweight whose treatment was reimbursed (divided into BMI subgroups) or non-reimbursed. The primary outcomes were proportions of participants in the reimbursed cohort achieving predefined weight loss targets with liraglutide 3.0 mg at Week 16 (≥5% and ≥7% for the lower BMI [28 to <35 kg/m2 with weight-related comorbidities] and higher BMI [≥35 kg/m2 ] subgroups, respectively) and Month 10 (additional ≥5% from Week 16; per Swiss reimbursement criteria). RESULTS: The full analysis set comprised 258 individuals (195 reimbursed; 63 non-reimbursed). In the reimbursed cohort, 139 individuals (71.3%) achieved their weight loss targets at Week 16. Of individuals who met the Week-16 criteria, 43.2% attained an additional 5% weight loss at Month 10. In 162 individuals for whom data were recorded at Month 10, the mean (standard deviation) relative weight loss from baseline to Month 10 was -12.4% (6.4%). CONCLUSIONS: Although reimbursement criteria may be difficult to achieve, particularly the additional weight loss of 5% from Week 16 to Month 10, a clinically relevant overall weight loss from baseline to Month 10 was shown in most individuals with obesity or overweight who received liraglutide 3.0 mg.

GLP-1 secretion is regulated by IL-6 signalling: a randomised, placebo-controlled study.

AIMS/HYPOTHESIS: IL-6 is a cytokine with various effects on metabolism. In mice, IL-6 improved beta cell function and glucose homeostasis via upregulation of glucagon-like peptide 1 (GLP-1), and IL-6 release from muscle during exercise potentiated this beneficial increase in GLP-1. This study aimed to identify whether exercise-induced IL-6 has a similar effect in humans. METHODS: In a multicentre, double-blind clinical trial, we randomly assigned patients with type 2 diabetes or obesity to intravenous tocilizumab (an IL-6 receptor antagonist) 8 mg/kg every 4 weeks, oral sitagliptin (a dipeptidyl peptidase-4 inhibitor) 100 mg daily or double placebos (a placebo saline infusion every 4 weeks and a placebo pill once daily) during a 12 week training intervention. The primary endpoints were the difference in change of active GLP-1 response to an acute exercise bout and change in the AUC for the concentration-time curve of active GLP-1 during mixed meal tolerance tests at baseline and after the training intervention. RESULTS: Nineteen patients were allocated to tocilizumab, 17 to sitagliptin and 16 to placebos. During the acute exercise bout active GLP-1 levels were 26% lower with tocilizumab (multiplicative effect: 0.74 [95% CI 0.56, 0.98], p = 0.034) and 53% higher with sitagliptin (1.53 [1.15, 2.03], p = 0.004) compared with placebo. After the 12 week training intervention, the active GLP-1 AUC with sitagliptin was about twofold that with placebo (2.03 [1.56, 2.62]; p < 0.001), while GLP-1 AUC values showed a small non-significant decrease of 13% at 4 weeks after the last tocilizumab infusion (0.87 [0.67, 1.12]; p = 0.261). CONCLUSIONS/INTERPRETATION: IL-6 is implicated in the regulation of GLP-1 in humans. IL-6 receptor blockade lowered active GLP-1 levels in response to a meal and an acute exercise bout in a reversible manner, without lasting effects beyond IL-6 receptor blockade. TRIAL REGISTRATION: Clinicaltrials.gov NCT01073826. FUNDING: Danish National Research Foundation. Danish Council for Independent Research. Novo Nordisk Foundation. Danish Centre for Strategic Research in Type 2 Diabetes. European Foundation for the Study of Diabetes. Swiss National Research Foundation.

Glucose-Dependent Insulinotropic Peptide Stimulates Glucagon-Like Peptide 1 Production by Pancreatic Islets via Interleukin 6, Produced by α Cells.

BACKGROUND & AIMS: Glucose-dependent insulinotropic peptide (GIP) induces production of interleukin 6 (IL6) by adipocytes. IL6 increases production of glucagon-like peptide (GLP)-1 by L cells and α cells, leading to secretion of insulin from ß cells. We investigated whether GIP regulates GLP1 and glycemia via IL6. METHODS: We obtained samples of human pancreatic islets and isolated islets from mice; human α cells and ß cells were sorted by flow cytometry and incubated with GIP. Islets were analyzed by quantitative polymerase chain reaction and immunohistochemistry. BKS.Cg-Dock7m+/+ Leprdb/J db/db mice (diabetic mice) and db/+ mice, as well as C57BL/6J IL6-knockout mice (IL6-KO) and C57BL/6J mice with the full-length Il6 gene (controls), were fed a chow or a high-fat diet; some mice were given injections of recombinant GIP, IL6, GLP, a neutralizing antibody against IL6 (anti-IL6), lipopolysaccharide, and/or IL1B. Mice were given a glucose challenge and blood samples were collected and analyzed. RESULTS: Incubation of mouse and human pancreatic α cells with GIP induced their production of IL6, leading to production of GLP1 and insulin secretion from pancreatic islets. This did not occur in islets from IL6-KO mice or in islets incubated with anti-IL6. Incubation of islets with IL1B resulted in IL6 production but directly reduced GLP1 production. Incubation of mouse islets with the sodium glucose transporter 2 inhibitor dapagliflozin induced production of GLP1 and IL6. Injection of control mice with GIP increased plasma levels of GLP1, insulin, and glucose tolerance; these effects were amplified in mice given lipopolysaccharide but reduced in IL6-KO mice or in mice given anti-IL6. Islets from diabetic mice had increased levels of IL1B and IL6, compared with db/+ mice, but injection of GIP did not lead to production of GLP1 or reduce glycemia. CONCLUSIONS: In studies of pancreatic islets from human beings and mice, we found that GIP induces production of IL6 by α cells, leading to islet production of GLP1 and insulin. This process is regulated by inflammation, via IL1B, and by sodium glucose transporter 2. In diabetic mice, increased islet levels of IL6 and IL1B might increase or reduce the production of GLP1 and affect glycemia.

Development of an Interleukin-1ß Vaccine in Patients with Type 2 Diabetes.

Interleukin-1ß (IL-1ß) is a key cytokine involved in inflammatory illnesses including rare hereditary diseases and common chronic inflammatory conditions as gout, rheumatoid arthritis, and type 2 diabetes mellitus, suggesting reduction of IL-1ß activity as new treatment strategy. The objective of our study was to assess safety, antibody response, and preliminary efficacy of a novel vaccine against IL-1ß. The vaccine hIL1bQb consisting of full-length, recombinant IL-1ß coupled to virus-like particles was tested in a preclinical and clinical, randomized, placebo-controlled, double-blind study in patients with type 2 diabetes. The preclinical simian study showed prompt induction of IL-1ß-specific antibodies upon vaccination, while neutralizing antibodies appeared with delay. In the clinical study with 48 type 2 diabetic patients, neutralizing IL-1ß-specific antibody responses were detectable after six injections with doses of 900 µg. The development of neutralizing antibodies was associated with higher number of study drug injections, lower baseline body mass index, improvement of glycemia, and C-reactive protein (CRP). The vaccine hIL1bQb was safe and well-tolerated with no differences regarding adverse events between patients receiving hIL1bQb compared to placebo. This is the first description of a vaccine against IL-1ß and represents a new treatment option for IL-1ß-dependent diseases such as type 2 diabetes mellitus (ClinicalTrials.gov NCT00924105).

Copeptin for risk stratification in non-traumatic headache in the emergency setting: a prospective multicenter observational cohort study.

BACKGROUND: In the emergency setting, non-traumatic headache is a benign symptom in 80% of cases, but serious underlying conditions need to be ruled out. Copeptin improves risk stratification in several acute diseases. Herein, we investigated the value of copeptin to discriminate between serious secondary headache and benign headache forms in the emergency setting. METHODS: Patients presenting with acute non-traumatic headache were prospectively enrolled into an observational cohort study. Copeptin was measured upon presentation to the emergency department. Primary endpoint was serious secondary headache defined by a neurologic cause requiring immediate treatment of the underlying disease. Secondary endpoint was the combination of mortality and hospitalization within 3 months. Two board-certified neurologist blinded to copeptin levels verified the endpoints after a structured 3-month-telephone interview. RESULTS: Of the 391 patients included, 75 (19%) had a serious secondary headache. Copeptin was associated with serious secondary headache (OR 2.03, 95%CI 1.52-2.70, p < 0.0001). Area under the curve (AUC) for copeptin to identify the primary endpoint was 0.70 (0.63-0.76). After adjusting for age > 50, focal-neurological abnormalities, and thunderclap onset of symptoms, copeptin remained an independent predictive factor for serious secondary headache (OR 1.74, 95%CI 1.26-2.39, p = 0.001). Moreover, copeptin improved the AUC of the multivariate logistic clinical model (p-LR-test < 0.001). Even though copeptin values were higher in patients reaching the secondary endpoint, this association was not significant in multivariate logistic regression. CONCLUSIONS: Copeptin was independently associated with serious secondary headache as compared to benign headaches forms. Copeptin may be a promising novel blood biomarker that should be further validated to rule out serious secondary headache in the emergency department. TRIAL REGISTRATION: Study Registration on 08/02/2010 as NCT01174901 at clinicaltrials.gov.

Interleukin-6 contributes to early fasting-induced free fatty acid mobilization in mice.

Contracting muscle releases interleukin-6 (IL-6) enabling the metabolic switch from carbohydrate to fat utilization. Similarly, metabolism is switched during transition from fed to fasting state. Herein, we examined a putative role for IL-6 in the metabolic adaptation to normal fasting. In lean C57BL/6J mice, 6 h of food withdrawal increased gene transcription levels of IL-6 in skeletal muscle but not in white adipose tissue. Concomitantly, circulating IL-6 and free fatty acid (FFA) levels were significantly increased, whereas respiratory quotient (RQ) was reduced in 6-h fasted mice. In white adipose tissue, phosphorylation of hormone-sensitive lipase (HSL) was increased on fasting, indicating increased lipolysis. Intriguingly, fasting-induced increase in circulating IL-6 levels and parallel rise in FFA concentration were absent in obese and glucose-intolerant mice. A causative role for IL-6 in the physiological adaptation to fasting was further supported by the fact that fasting-induced increase in circulating FFA levels was significantly blunted in lean IL-6 knockout (KO) and lean C57BL/6J mice treated with neutralizing IL-6 antibody. Consistently, phosphorylation of HSL was significantly reduced in adipose tissue of IL-6-depleted mice. Hence, our findings suggest a novel role for IL-6 in energy supply during early fasting.

Breaking down barriers to bariatric care: a qualitative study on how telemedicine could transform patient experiences in a Swiss monocentric setting.

OBJECTIVE: Telemedicine is becoming an increasingly feasible option for patients with chronic diseases due to its convenience, cost-effectiveness and ease of access. While there are certain limitations, the benefits can be appreciated by those seeking repetitive care. The perception of telemedicine as an alternative to recurrent, in-person appointments for patients with obesity in structured bariatric programmes is still unclear. This content analysis' primary endpoint was to explore how patients within our bariatric programme perceived telemedicine and virtual consultations as a new way of communication during COVID-19. DESIGN: A qualitative study using semistructured interviews and qualitative content analysis method by Elo and Kyngäs following four steps: data familiarisation, coding and categorising with Quirkos software and final interpretation guided by developed categories. SETTING: University Hospital, Switzerland. PARTICIPANTS: We conducted 33 interviews with 19 patients from a structured bariatric programme. RESULTS: Most patients shared positive experiences, acknowledging the convenience and accessibility of virtual appointments. Others voiced concerns, especially regarding telemedicine's limitations. These reservations centred around the lack of physical examinations, difficulties in fostering connections with healthcare providers, as well as barriers stemming from language and technology. The research identified a spectrum of patient preferences in relation to telemedicine versus in-person visits, shaped by the immediacy of their concerns and their availability. CONCLUSION: While telemedicine is increasingly accepted by the public and provides accessible and cost-effective options for routine follow-up appointments, there are still obstacles to overcome, such as a lack of physical examination and technological limitations. However, integrating virtual alternatives, like phone or video consultations, into routine bariatric follow-ups could improve continuity and revolutionise bariatric care.

Glucose-dependent insulinotropic polypeptide induces cytokine expression, lipolysis, and insulin resistance in human adipocytes.

Obesity-related insulin resistance is linked to a chronic state of systemic and adipose tissue-derived inflammation. Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone also acting on adipocytes. We investigated whether GIP affects inflammation, lipolysis, and insulin resistance in human adipocytes. Human subcutaneous preadipocyte-derived adipocytes, differentiated in vitro, were treated with human GIP to analyze mRNA expression and protein secretion of cytokines, glycerol, and free fatty acid release and insulin-induced glucose uptake. GIP induced mRNA expression of IL-6, IL-1ß, and the IL-1 receptor antagonist IL-1Ra, whereas TNFα, IL-8, and monocyte chemotactic protein (MCP)-1 remained unchanged. Cytokine induction involved PKA and the NF-κB pathway as well as an autocrine IL-1 effect. Furthermore, GIP potentiated IL-6 and IL-1Ra secretion in the presence of LPS, IL-1ß, and TNFα. GIP induced lipolysis via activation of hormone-sensitive lipase and was linked to NF-κB activation. Finally, chronic GIP treatment impaired insulin-induced glucose uptake possibly due to the observed impaired translocation of glucose transporter GLUT4. In conclusion, GIP induces an inflammatory and prolipolytic response via the PKA -NF-κB-IL-1 pathway and impairs insulin sensitivity of glucose uptake in human adipocytes.

The Role of the Olfactory System in Obesity and Metabolism in Humans: A Systematic Review and Meta-Analysis.

Obesity, linked to chronic diseases, poses a global health challenge. While the role of the olfactory system in energy homeostasis is well-documented in rodents, its role in metabolism regulation and obesity in humans remains understudied. This review examines the interplay between olfactory function and metabolic alterations in human obesity and the effects of bariatric surgery on olfactory capabilities in humans. Adhering to PRISMA guidelines, a systematic review and meta-analysis was conducted, focusing exclusively on original human studies. From 51 articles, 14 were selected for the meta-analysis. It was found that variations in olfactory receptor genes influence the susceptibility to odors and predisposition to weight gain and poor eating habits. Bariatric surgery, particularly sleeve gastrectomy, shows significant improvements in olfactory function (SMD 2.37, 95% CI [0.96, 3.77], I = 92%, p = 0.001), especially regarding the olfactory threshold (SMD -1.65, 95% CI [-3.03, -0.27], I = 81%, p = 0.02). There is a bidirectional relationship between olfactory function and metabolism in humans. Bariatric surgery improves olfactory perception in obese patients, but it is still unclear if impacting the olfactory system directly affects eating behavior and the energy balance. However, these findings open novel avenues for future studies addressing the olfactory system as a novel target to alter systemic metabolism in humans.

Sex-specific differences in metabolic hormone and adipose tissue dynamics induced by moderate low-carbohydrate and ketogenic diet.

Low-carbohydrates diets are increasingly used to treat obesity and metabolic disorders. A very low-carbohydrate, ketogenic diet is hard to follow and, due to the very high fat content, linked to severe side effects, like hyperlipidemia and atherogenesis. Therefore, a less restrictive, unsaturated fat-based low-carbohydrate diet appears as a promising alternative. Since neither sex differences, nor their effect on specific metabolic hormones and adipose tissue compartments have been investigated thoroughly in these diets, we aimed to analyze their dynamics and metabolic factors in mice. We found a significant sexual dimorphism with decreased body weight and subcutaneous fat only in males on ketogenic diet, while diminished insulin, elevated ghrelin and FGF-21 were present with a differential time course in both sexes. The non-ketogenic moderate low-carbohydrate diet increased body weight and perigonadal fat in females, but induced leptin elevation in males. Both diets enhanced transiently TNFɑ only in males and had no impact on behavior. Altogether, these results reveal complex sex-dependent effect of dietary interventions, indicating unexpectedly females as more prone to unfavorable metabolic effects of low-carbohydrate diets.

The Impact of the COVID-19 Pandemic on Patients from a Bariatric Program: A Qualitative Analysis of Their Perceptions of Health and Well-Being.

INTRODUCTION: The study was conducted to explore the perceptions of patients from a bariatric program who have undergone or will undergo bariatric surgery during the ongoing COVID-19 pandemic, specifically as related to their struggles with health issues and their psychological well-being. MATERIALS AND METHODS: We conducted semi-structured, in-depth interviews with nineteen pre- or post-bariatric patients to generate data on their perceptions of COVID-19. Consistent with the methods of constructivist grounded theory, we collected and analyzed data iteratively through a constant comparative process for data coding and develop themes in the transcripts. RESULTS: We identified themes to summarize the pandemic-associated experiences of our cohort as follows: their life structure before COVID-19, the turning point with changes and adaptations, and the impact of isolation on psychological well-being. We identified grief due to loss of social contacts as well as physical and psychological health impairment as consequences of pandemic-related lifestyle changes. Most participants were not aware of overweight and obesity being major risk factors for worse outcomes of COVID-19. We developed a theme-based theory on patients' perceptions and fears regarding the pandemic as they live through phases of grief. DISCUSSION: Most participants shared critical perceptions about their own somatic and psychological health. These findings may inform recommendations and strategies for both patients and healthcare professionals to manage the challenges potentially presented by this vulnerable patient group in the context of the COVID-19 pandemic.

Regular intake of energy drinks and multivitamin supplements is associated with elevated plasma vitamin B6 levels in post-bariatric patients.

The aim of the present survey was to analyze plasma vitamin B6 levels in post-bariatric patients and to elucidate the causal factors associated with elevated plasma vitamin B6 levels. This is a retrospective analysis of electronic patient data of all post-bariatric patients evaluated at the endocrine outpatient clinic of the University Hospital Basel in 2017, for which plasma vitamin B6 values were assessed during regular follow-up visits. In total, 205 patients were included in the study, whereof a minority of 43% had vitamin B6 levels in the normal range. 50% of the patients had vitamin B6 levels up to fourfold higher than the upper normal limit and 7% had levels more than fourfold above the upper normal limit. Vitamin B6 deficiency was not observed in any patient. While multivitamin supplementation in general was associated with elevated plasma vitamin B6 levels, the highest vitamin B6 levels were found after biliopancreatic diversion (BPD) and in patients who reported daily energy drink intake. Elevated plasma vitamin B6 levels up to fourfold above the upper normal limit are common in postbariatric patients and are associated with regular multivitamin supplementation, while highly elevated plasma vitamin B6 levels were seen primarily upon regular energy drink intake. Thus, a regular follow-up of vitamin B6 plasma levels and critical evaluation of vitamin B6 supplementation, either as part of the multivitamin preparation or related to regular energy drink intake, is highly warranted and should be an integral part of the routine post-bariatric follow-up.

IL-6 Receptor Blockade Increases Circulating Adiponectin Levels in People with Obesity: An Explanatory Analysis.

Human obesity is associated with decreased circulating adiponectin and elevated leptin levels. In vitro experiments and studies in high fat diet (HFD)-fed mice suggest that interleukin-6 (IL-6) may regulate adiponectin and leptin release from white adipose tissue (WAT). Herein, we aimed to investigate whether IL-6 receptor blockade affects the levels of circulating adiponectin and leptin in obese human individuals. To this end, serum samples collected during a multicenter, double-blind clinical trial were analyzed. In the latter study, obese human subjects with or without type 2 diabetes were randomly assigned to recurrent placebo or intravenous tocilizumab (an IL-6 receptor antibody) administration during a 12-week exercise training intervention. Twelve weeks of tocilizumab administration (in combination with exercise training) trend wise enhanced the decrease in circulating leptin levels (-2.7 ± 8.2% in the placebo vs. -20.6 ± 5.6% in tocilizumab, p = 0.08) and significantly enhanced the increase in circulating adiponectin (3.4 ± 3.7% in the placebo vs. 27.0 ± 6.6% in tocilizumab, p = 0.01). In addition, circulating adiponectin levels were negatively correlated with the homeostatic model assessment of insulin resistance (HOMA-IR), indicating that increased adiponectin levels positively affect insulin sensitivity in people with obesity. In conclusion, IL-6 receptor blockade increases circulating adiponectin levels in people with obesity.

GLP-1 Receptor Signaling in Astrocytes Regulates Fatty Acid Oxidation, Mitochondrial Integrity, and Function.

Astrocytes represent central regulators of brain glucose metabolism and neuronal function. They have recently been shown to adapt their function in response to alterations in nutritional state through responding to the energy state-sensing hormones leptin and insulin. Here, we demonstrate that glucagon-like peptide (GLP)-1 inhibits glucose uptake and promotes ß-oxidation in cultured astrocytes. Conversely, postnatal GLP-1 receptor (GLP-1R) deletion in glial fibrillary acidic protein (GFAP)-expressing astrocytes impairs astrocyte mitochondrial integrity and activates an integrated stress response with enhanced fibroblast growth factor (FGF)21 production and increased brain glucose uptake. Accordingly, central neutralization of FGF21 or astrocyte-specific FGF21 inactivation abrogates the improvements in glucose tolerance and learning in mice lacking GLP-1R expression in astrocytes. Collectively, these experiments reveal a role for astrocyte GLP-1R signaling in maintaining mitochondrial integrity, and lack of GLP-1R signaling mounts an adaptive stress response resulting in an improvement of systemic glucose homeostasis and memory formation.

CerS1-Derived C18:0 Ceramide in Skeletal Muscle Promotes Obesity-Induced Insulin Resistance.

Skeletal muscle accumulates ceramides in obesity, which contribute to the development of obesity-associated insulin resistance. However, it remained unclear which distinct ceramide species in this organ contributes to instatement of systemic insulin resistance. Here, ceramide profiling of high-fat diet (HFD)-fed animals revealed increased skeletal muscle C18:0 ceramide content, concomitant with increased expression of ceramide synthase (CerS)1. Mice lacking CerS1, either globally or specifically in skeletal muscle (CerS1ΔSkM), exhibit reduced muscle C18:0 ceramide content and significant improvements in systemic glucose homeostasis. CerS1ΔSkM mice exhibit improved insulin-stimulated suppression of hepatic glucose production, and lack of CerS1 in skeletal muscle improves systemic glucose homeostasis via increased release of Fgf21 from skeletal muscle. In contrast, muscle-specific deficiency of C16:0 ceramide-producing CerS5 and CerS6 failed to protect mice from obesity-induced insulin resistance. Collectively, these results reveal the tissue-specific function of distinct ceramide species during the development of obesity-associated insulin resistance.

Exercise upregulates copeptin levels which is not regulated by interleukin-1.

OBJECTIVE: Studies have suggested that arginine vasopressin (AVP) and its surrogate marker copeptin increase during exercise, independently of serum sodium and/or osmolality. In extreme cases, this can lead to runners-induced hyponatremia. Interleukin-1 (IL-1) increases during exercise and induces AVP in animal models. We here therefore investigate whether copeptin (a surrogate marker for AVP) increases upon exercise in young and healthy males, and whether this increase is regulated by IL-1. DESIGN: In a randomized, placebo-controlled, double-blind, crossover trial in 17 healthy male volunteers, the effect of the IL-1 receptor antagonist anakinra on exercise-induced copeptin was compared with placebo. METHODS: Participants exercised for one hour at 75% of VO2max and were not allowed to drink/eat 6 hours before and during the study. Participants received either 100 mg of anakinra or placebo 1h before exercise. Blood was drawn at certain time intervals. RESULTS: In both groups, copeptin levels were induced by 2.5-fold upon exercise (p<0.001), from 4.5-10.6 pmol/l in the placebo, and 4.3-11.3 pmol/l in the anakinra group, (p = 0.38). One hour after exercise, copeptin levels dropped to 7.7 and 7.9 pmol/l in the placebo and anakinra group, respectively (p = 0.58). The increase of copeptin levels was not explained by sodium concentrations. CONCLUSIONS: Exercise induces a continuous rise of plasma copeptin levels in healthy male volunteers independently of sodium levels and fluid intake. This increase is not regulated by the IL-1 pathway.