Effects Of Glucagon-like Peptide-2 Research Articles

Glucagon-Like-Peptide-2 Stimulates Lacteal Contractility and Enhances Chylomicron Transport in the Presence of an Intact Enteric Nervous System

Secretion and transport of intestinal chylomicrons (CMs) via lymphatics to the blood circulation is stimulated primarily by fat ingestion, whereas several other factors have also been shown to play important roles in regulating CM secretion rate. Among these factors, active regulation of lymphatic pumping has not been appreciated to date. The gut peptide and intestinal growth factor glucagon-like peptide-2 (GLP-2) has emerged as a robust enhancer of intestinal lipid mobilization and secretion. The present study aims to elucidate GLP-2's impact on lacteal contractility and assess enteric nervous system (ENS) involvement in GLP-2-induced effects on lipid mobilization. Using intravital imaging of a prospero-related homeobox 1-enhanced green fluorescent protein rat model, we assessed GLP-2's effect on lacteal contractility, in the presence and absence of the ENS inhibitor mecamylamine (MEC). Concurrently, to explore the physiological relevance, we examined GLP-2's impact on lymph flow and triglyceride (TG) output invivo in a rat lymph fistula model. GLP-2 significantly increased lacteal contractility, and this effect was inhibited by MEC. In the rat lymph fistula model, GLP-2 increased lymph flow, lymph volume, cumulative lymph volume, and TG output while reducing lymph TG concentration. MEC administration blocked these effects of GLP-2. Peak enhancement of lacteal contractility and enhancement of lymph flow invivo occurred simultaneously with maximal effect at 15-20 minutes post GLP-2 administration, suggesting that GLP-2 enhances lipid transport by stimulating lymphatic contractility. For the first time, through imaging and concurrent rat lymphatic fistula studies, we demonstrated active regulation of lymphatic contractility as a key determinant of CM secretion and that intact ENS was required to observe this effect.

Integrative analysis revealed the role of glucagon-like peptide-2 in improving experimental colitis in mice by inhibiting inflammatory pathways, regulating glucose metabolism, and modulating gut microbiota.

Ulcerative colitis (UC) is an inflammatory bowel disease characterized by recurrent and remitting inflammation of the mucosa of the colon and rectum, the incidence of which is on the rise. Glucagon-like peptide-2 (GLP-2) is a newly discovered neurotrophic factor, but its efficacy and mechanism of action in UC remain unclear. In this study, we investigated the protective effects and potential targets of GLP-2 on dextran sodium sulfate (DSS)-induced UC in mice through integrative analysis. The effects of GLP-2 on UC were assessed by calculating the disease activity index, colonic mucosal damage index, and pathological histological scores. Enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry were used to detect the expression of GLP-2, nuclear factor kappa-B (NF-κB), interleukin-6 (IL-6), and signal transducer and activator of transcription-3 (STAT3). The 16SrRNA gene was used to detect changes in gut microbiota in mouse colonic tissues, and oral glucose tolerance test (OGTT) blood glucose levels were used to analyze the differences in flora. The results showed that GLP-2 could reduce the inflammation of UC mice, which may be achieved by inhibiting the potential targets of NF-κB, and Janus kinase (JAK)/STAT3 inflammatory pathways, regulating sugar metabolism, increasing dominant species, and improving microbial diversity. This study provides new insight into the potential of GLP-2 for achieving more ideal UC treatment goals in future.

The Gut-Bone Axis in Diabetes.

To describe recent advances in the understanding of how gut-derived hormones regulate bone homeostasis in humans with emphasis on pathophysiological and therapeutic perspectives in diabetes. The gut-derived incretin hormone glucose-dependent insulinotropic polypeptide (GIP) is important for postprandial suppression of bone resorption. The other incretin hormone, glucagon-like peptide 1 (GLP-1), as well as the intestinotrophic glucagon-like peptide 2 (GLP-2) has been shown to suppress bone resorption in pharmacological concentrations, but the role of the endogenous hormones in bone homeostasis is uncertain. For ambiguous reasons, both patients with type 1 and type 2 diabetes have increased fracture risk. In diabetes, the suppressive effect of endogenous GIP on bone resorption seems preserved, while the effect of GLP-2 remains unexplored both pharmacologically and physiologically. GLP-1 receptor agonists, used for the treatment of type 2 diabetes and obesity, may reduce bone loss, but results are inconsistent. GIP is an important physiological suppressor of postprandial bone resorption, while GLP-1 and GLP-2 may also exert bone-preserving effects when used pharmacologically. A better understanding of the actions of these gut hormones on bone homeostasis in patients with diabetes may lead to new strategies for the prevention and treatment of skeletal frailty related to diabetes.

GLP-2 Regulation of Dietary Fat Absorption and Intestinal Chylomicron Production via Neuronal Nitric Oxide Synthase (nNOS) Signaling.

Postprandial dyslipidemia is a metabolic condition commonly associated with insulin-resistant states, such as obesity and type 2 diabetes. It is characterized by the overproduction of intestinal chylomicron particles and excess atherogenic chylomicron remnants in circulation. We have previously shown that glucagon-like peptide 2 (GLP-2) augments dietary fat uptake and chylomicron production in insulin-resistant states; however, the underlying mechanisms remain unclear. Previous studies have implicated nitric oxide (NO) in the absorptive actions of GLP-2. In this study, we report a novel role for neuronal NO synthase (nNOS)-mediated NO generation in lipid uptake and chylomicron formation based on studies in C57BL/6J mice, nNOS-/- mice, and Syrian golden hamsters after intraduodenal and oral fat administration. GLP-2 treatment in wild-type (WT) mice significantly increased postprandial lipid accumulation and circulating apolipoprotein B48 protein levels, while these effects were abolished in nNOS-/- mice. nNOS inhibition in Syrian golden hamsters and protein kinase G (PKG) inhibition in WT mice also abrogated the effect of GLP-2 on postprandial lipid accumulation. These studies demonstrate a novel mechanism in which nNOS-generated NO is crucial for GLP-2-mediated lipid absorption and chylomicron production in both mouse and hamster models. Overall, our data implicate an nNOS-PKG-mediated pathway in GLP-2-mediated stimulation of dietary fat absorption and intestinal chylomicron production.

Novel ultrasound approaches permit the visualisation of the microvascular effects of glucagon-like peptide-2 in the gut with unprecedented resolution

Novel ultrasound approaches permit the visualisation of the microvascular effects of glucagon-like peptide-2 in the gut with unprecedented resolution

Glucagon-Like Peptide-2 Modulates Enteric Paneth Cells Immune Response and Alleviates Gut Inflammation During Intravenous Fluid Infusion in Mice With a Central Catheter.

Background: Glucagon-like peptide-2 (GLP-2) has protective effects on gastrointestinal functions. Our previous study found that GLP-2 could significantly reduce intestinal permeability and bacterial translocation in total parenteral nutrition (TPN) animal model. However, the effects of GLP-2 on the impairment of the intestinal Paneth cells immune function and gut inflammation during intravenous fluid infusion mainly consisted of nutritional materials is currently scattered.Objective: The current study was aimed to investigate the efficacy of the GLP-2 in alleviating gut inflammation and modulating enteric Paneth cells immune response in parenterally fed mice and its underlying mechanisms.Methods: Thirty-six male ICR mice underwent venous catheterization were divided into 3 groups: Chow, TPN, and TPN+GLP-2 groups. GLP-2 was administered intravenously at 60 μg/day for 5 days. The small intestine tissue and serum samples were collected on the 7th day.Results: Compared with the TPN group, the expression of tight junction proteins occludin and claudin-1 were significantly increased in the TPN+GLP-2 group. In addition, the expression of lysozyme, sPLA2, insulin-like growth factor-1, and epithelial protection and repair genes were improved in the TPN+GLP-2 group. The levels of IL-6 and TNF-α proteins and mRNAs in the ileum tissues were remarkably reduced in the TPN+GLP-2 group, while IL-10 protein and mRNA level were elevated in the TPN+GLP-2 group (all p < 0.05). Moreover, the TPN+GLP-2 group has higher levels of serum endotoxin, D-lactic acid, and MPO than those of the TPN group.Conclusions: GLP-2 alleviated gut inflammation and improved enteric Paneth cells immune responses through intravenous fluid infusion, possibly by improving the functioning of epithelial protection and repair, and reducing mucosal inflammatory responses.

258-OR: The Glucagonotropic Effect of GLP-2 during Hypoglycemia, Euglycemia, and Hyperglycemia in Healthy Men: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

To determine whether the glucagonotropic gut-derived hormone glucagon-like peptide 2 (GLP-2) might be exploited as a safeguard against insulin-induced hypoglycemia, we evaluated the effects of exogenous GLP-2 during hypoglycemia, euglycemia and hyperglycemia. Ten healthy, young men underwent six randomized study days: two insulin-induced hypoglycemic clamps (2.5 mmol/L), two euglycemic clamps, and two hyperglycemic clamps (10 mmol/L). At each glycemic level, double-blinded intravenous infusion with GLP-2 (6 pmol/kg/minfrom −10 to 0 min, and 2 pmol/kg/min from 0 to 90 min) or placebo was given. Compared to placebo, exogenous GLP-2 increased glucagon secretion (assessed by baseline-subtracted area under curve) during euglycemia ([mean ± SD] −141±159 pmol/L×min vs. 261±200 pmol/L×min, P=0.0005), but not during hypo- and hyperglycemia. However, compared to placebo, GLP-2 increased glucagon secretion during the initial 40 minutes of the hypoglycemic clamp (38±81 pmol/L×min vs. 174±82 pmol/L×min, P=0.0007).In conclusion, the glucagonotropic effect of GLP-2 is evident at euglycemia and - to a lesser extent - during hypoglycemia, but not during hyperglycemia; positioning GLP-2 as a potential plasma glucose-stabilizer, which perhaps may be utilized therapeutically as a safeguard against insulin-induced hypoglycemia.View largeDownload slideView largeDownload slide DisclosureN. L. Hansen: None. T. Magnussen: None. J. J. Holst: Consultant; Self; Novo Nordisk, Other Relationship; Self; Antag Therapeutics, Bainan Biotech, MSD Corporation, Novo Nordisk, Other Relationship; Spouse/Partner; Antag Therapeutics, Bainan Biotech, Synklino ApS. B. Hartmann: None. M. B. Christensen: None. A. Lund: Speaker’s Bureau; Self; Novo Nordisk, Sanofi. F. K. Knop: Advisory Panel; Self; MSD Corporation, Novo Nordisk A/S, Sanofi, Consultant; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Novo Nordisk A/S, Pharmacosmos, Zealand Pharma A/S, Research Support; Self; Novo Nordisk A/S, Zealand Pharma A/S, Speaker’s Bureau; Self; AstraZeneca, Bayer AG, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, MSD Corporation, Novo Nordisk A/S.

Melanocortin receptor-4 mediates the anorectic effect induced by the nucleus tractus solitarius injection of glucagon-like Peptide-2 in fasted rats

Glucagon-like peptide-2 (GLP-2) is secreted from enteroendocrine L-type cells of the gut and also released from preproglucagonergic (PPG) neurons in the nucleus tractus solitarius (NTS) and adjacent medial reticular nucleus of the brain stem. The neurons in the NTS express GLP-2, and the neurons send extensive projections to the hypothalamus. Recent studies show that the intracerebroventricular administration of GLP-2 significantly suppresses food intake in animals and some evidence suggest that the melanocortin receptor-4 (MC4-R) signaling in the hypothalamus is required for intracerebroventricular GLP-2-mediated inhibition of feeding. There is proopiomelanocortin (POMC) positive neurons expressing MC4-R in the NTS. Suppression of MC4-R expressing neurons in the brain stem inhibits gastric emptying. In this study, we tested the effects of NTS GLP-2R activation and blockade on feeding behavior and evaluated the endogenous melanocortin system's role in the NTS in mediating effects of GLP-2 on feeding behavior in fed and fasted rats. Our results demonstrated that microinjection of GLP-2 into the NTS suppressed food intake in fasted-refeeding rats but did not affect food intake in free-feeding rats, and this inhibition was blocked by pretreatment of either Exendin (9–39) or SHU 9119, suggesting the GLP-2 system in the NTS exerts an inhibitory action on food intake. MC4-R mediates this action in the NTS.

Glucagon-like Peptide-2 (GLP-2) Treatment Reduces Gvhd-Related Mortality in a Pre-Clinical Transplant Model Via Expansion of Macrophages with Tolerogenic Potential

The gastrointestinal (GI) tract is a major target in GVHD. Conditioning-induced damage and mucosal barrier disruption are important factors in GVHD, however therapies targeting these processes have not been identified. Glucagon-like-peptide 2 (GLP-2) is an enterocyte-specific growth factor produced by L cells that has regenerative potential in models of GI damage. Its impact on the mucosal immune system has not been elucidated. We sought to examine the therapeutic and immunologic effect of GLP-2 in murine GVHD. We employed a major MHC-mismatched GVHD model (C57BL/6J → BALB/cJ). Mice were treated with 800nmol/kg/day of Elsiglutide (a GLP-2 analogue, provided by Helsinn) or vehicle beginning on D+1 for 30 days. Treatment with GLP-2 significantly improved survival and GVHD scores (Fig. 1A), while increasing small intestine mass and villi length (Fig 1B). GLP-2 also reduced T-cell infiltration into the jejunum (Fig. 1C). Analysis of intestinal immune cells by 28-color flow cytometry revealed dramatic differences between treatment groups in both myeloid- and T-cells. On D+14, GLP-2 led to an increased proportion of donor CSF-1R+ macrophages in the lamina propria (LP) (Fig. 2A) - cells that support the maintenance of the intestinal stem cell niche (Sehgal, Nat Commun, 2018). On D+21 the LP donor myeloid compartment was further altered, especially in MHC IIlow F4/80+ CD64+ macrophages (Fig. 2B, C). Here GLP-2 treatment expanded macrophages with lower expression of the co-stimulatory molecules CD80 and CD86 as well as the phagocytic marker CD206, whilst increasing the inhibitory molecule SIRPα, consistent with a tolerogenic phenotype. GLP-2 treatment also increased CX3CR1 expression on MHC IIlow macrophages with reduced Ly6C - a phenotype associated with physiologic macrophage maturation and linked to the resolution of colitis (Zigmond, Immunity, 2012). Vehicle-treated mice, conversely, had predominance of Ly6Chigh MHC IIlow LP macrophages reminiscent of an early infiltrating phenotype and near absence of mature macrophages, suggesting an impaired monocyte-macrophage transition that was restored by GLP-2. In addition, GLP-2 treatment led to significant changes in donor intraepithelial lymphocytes on D+21 (Fig. 2D), where CD8 T cells exhibited decreased CD27, CD103 and CXCR3 expression but higher PD-1, suggesting less activation. To assess potential mechanisms for the differences in macrophage and T-cell phenotype, we examined the impact of GLP-2 on the intestinal microbiota. A syngeneic BALB/cJ model was used to explore the effects of GLP-2 independent of GVHD. Stool samples from D+0, D+14, and D+28 were subjected to 16S rRNA sequencing. Vehicle-treated mice had distinct β-diversity clusters at all time-points, showing a transplant effect on the microbiota (Fig. 3A). GLP-2-treated mice had near-complete cluster overlap between D+0 and D+14, suggesting attenuation of the impact of conditioning. GLP-2 treated mice were significantly enriched for Akkermansia muciniphila and Bacteroidales S24-7 family at D+14 and D+28 (Fig. 3B). These taxa have been associated with anti-inflammatory properties and A. muciniphila abundance is linked to epithelial mucin production, which is increased by GLP-2. We then assessed the role of microbial communities in the protective effect of GLP-2 by conducting an allogeneic transplant with 3 caging conditions; 1) vehicle and GLP-2 treated mice caged together, 2) caged separately, or 3) caged separately plus oral antibiotics. We observed a clear cage effect where co-housing the treatment groups improved the survival of vehicle treated mice (Fig. 3C), suggesting transferal of the therapeutic effect via the microbiome. Antibiotic administration also dampened the beneficial effect of GLP-2. Finally, we conducted a GvL experiment by co-transplanting Luc-A20 and monitoring tumor progression via bioluminescence imaging. Both GLP-2 and vehicle-treated mice eliminated the tumor, whereas mice receiving T-cell depleted bone marrow showed tumor progression (Fig. 3D). In summary, our results demonstrate high therapeutic potential of GLP-2 in GVHD. GLP-2 administration led to reduced mortality, modified the microbiome and altered the intestinal immune response to a more tolerogenic state. This novel mechanism sheds light on the role of the enteroendocrine system in maintaining gut homeostasis and sets the stage for therapeutic clinical trials. Figure 1 Disclosures Uhlemann: Allergan: Research Funding; GSK: Research Funding; Merck: Research Funding. Reshef:Gilead: Consultancy; Magenta: Consultancy; Novartis: Consultancy; Monsato: Consultancy; Atara: Consultancy; BMS: Consultancy.

Glucagon-like peptide 2 attenuates intestinal mucosal barrier injury through the MLCK/pMLC signaling pathway in a piglet model.

Glucagon-like peptide-2 (GLP-2), an intestinotrophic hormone, has drawn considerable attention worldwide due to its potential to promote intestinal development. We investigated the effects and mechanisms of GLP-2 against lipopolysaccharide (LPS)-induced intestinal inflammation and injury both in vitro and in vivo. Forty healthy piglets weaned at the age of 28 days with similar body weight (BW) were assigned to four in vivo treatments with ten piglets each: (i) nonchallenged control; (ii) LPS-challenged control; (iii) LPS + low dose GLP-2; and (iv) LPS + high dose GLP-2. Piglets were subcutaneously injected with phosphate-buffered saline supplemented with GLP-2 at doses of 0, 0, 2, and 10 nmol/kg BW per day for seven consecutive days. The piglets were challenged with an intraperitoneal injection with 100 μg/kg LPS on day 14 to induce intestinal damage. After that, the gene and protein expression levels of representative tight junction proteins and myosin light-chain kinase (MLCK)/phosphorylated myosin light chain (pMLC), as well as proinflammatory cytokine levels were determined using quantitative reverse transcription polymerase chain reaction, western blot, and enzyme-linked immunosorbent assay methods. A high dose of GLP-2 pretreatment increased intestinal permeability by downregulating and redistributing tight junction proteins (p < .05), for example, zona occluden-1 (ZO-1) and occludin. GLP-2 decreased the transcription of proinflammatory cytokines genes including interleukin-1β (IL-1β), IL-6, IL-8, and tumor necrosis factor-α in small intestines (p < .05). GLP-2 prevented the LPS-induced increase in the expression of MLCK dose-dependently and the increase in pMLC levels in the duodenum, jejunum, and ileum. To assess further the protective effect of GLP-2 on LPS-induced intestinal barrier injury after weaning and its possible mechanism, an in vitro intestinal epithelial barrier model was established with IPEC-J2 monolayers and treated with 100 μg/ml LPS with or without 1 × 10-8 mol/L GLP-2 pretreatment. The in vitro analysis included control, LPS, and GLP-2 + LPS treatments. GLP-2 treatment alleviated the destructive effect of LPS on barrier permeability by restoring the expression and ultrastructure of ZO-1 and occludin (p < .05). In addition, GLP-2 reversed the LPS-induced MLCK hyperexpression and pMLC hyperphosphorylation (p < .05). Taken together, our findings revealed a mechanism by which GLP-2 alleviated LPS-challenged intestinal barrier injury and inflammation in weaned piglets and IPEC-J2 cells via the MLCK/pMLC signaling pathway.

37-LB: GLP-2 Regulation of Dietary Fat Absorption and Intestinal Lipoprotein Production: The Role of the Enteric Nervous System via nNOS Signaling

Objective: Postprandial dyslipidemia, a condition commonly presented in individuals with type 2 diabetes (T2D), is characterized by the overproduction of triglyceride (TG)-rich lipoproteins (TRL). This results in excess atherogenic chylomicron (CM) remnants in circulation, significantly increasing the risk of cardiovascular disease (CVD). Using a Syrian golden hamster model, our laboratory has revealed that intestinal hormone glucagon-like peptide-2 (GLP-2) regulates dietary fat uptake and increases CM production in insulin-resistant states. However, the mechanisms by which GLP-2 enhances CM production remain unclear. Previous studies have implicated nitric oxide (NO) in the actions of GLP-2, demonstrating the requirement of NO in CM secretion. Therefore, this study investigated the role of neuronal NO synthase (nNOS)-mediated NO generation in lipid uptake and CM formation. Methods: nNOS-/- and C57BL/6 (WT) mice received an intraduodenal injection of olive oil, followed by an acute intraperitoneal (i.p.) injection of GLP-2 (0.25mg/kg; n=7) or vehicle (PBS; n=8). Blood samples were collected over a 2-hour period to assess postprandial lipid accumulation, and TRL fractions were isolated via ultracentrifugation. Immunoblotting was used to measure plasma apolipoprotein B48 (apoB48) protein expression. Results: While GLP-2-treated WT mice showed characteristic rises in postprandial TG and cholesterol in whole plasma and TRL fractions, the effect of GLP-2 in nNOS-/- mice was abolished. The effect of GLP-2 on postprandial plasma apoB48 protein expression was also abolished in nNOS-/- mice relative to GLP-2-treated WT mice. Conclusions: These findings demonstrate a novel mechanism in which nNOS-generated NO is crucial for GLP-2-mediated lipid absorption and CM production in the postprandial state. Understanding this pathway will provide insight for future therapeutic interventions to treat lipid disorders in T2D. Disclosure E.M. Grande: None. K. Adeli: None. Funding Canadian Institutes of Health Research

295 - Perceived stress of Hungarian dermatological outpatients based on the 2nd ESDaP Study

Glucagon-like peptide 2 (GLP-2) analogues are approved for adults with intestinal failure (IF), but no studies have included infants. This study examined the pharmacokinetics (PK), safety, and nutritional effects of GLP-2 in infants with IF.With parental consent (Health Canada Protocol:150,979), parenteral nutrition (PN)-dependent infants were treated with 5–20-μg/kg/day GLP-2 for 3 days (phase 1), and if tolerated continued for 42 days (phase 2). Nutritional therapy was by primary caregivers, and follow-up was to one year.Six patients were enrolled, age 5.4 ± 3.2 months, bowel length: 27 ± 12% of predicted, PN dependent (67 ± 18% of calories). GLP-2 did not affect vital signs, nor were there significant adverse events during the trial. Dosing 5 μg/kg/day gave GLP-2 levels of 52–57 pmol/L, with no change in half-life or endogenous GLP-2 levels. Enteral feeds, weight, Z scores, stooling frequency, and citrulline levels improved numerically. The trial was discontinued early because of a drop in potency.GLP-2 was well tolerated in infants, and pK was similar to children with no changes in endogenous GLP-2 release. The findings suggest that GLP-2 ligands may be safely used in infants and may have beneficial effects on nutritional status. Further study is required.2b Prospective Interventional Study.

Exosomes-mediated Transfer of miR-125a/b in Cell-to-cell Communication: A Novel Mechanism of Genetic Exchange in the Intestinal Microenvironment.

Glucagon-like peptide-2 (GLP-2), a key factor in intestinal rehabilitation therapy of short bowel syndrome (SBS), may require cell-to-cell communication to exert its biological functions. However, understanding of the mechanism remains elusive. Here, we report participation of exosomal miR-125a/b in GLP-2 mediated intestinal epithelial cells-myofibroblasts cross-talk in intestinal microenvironment.Methods: The effects of GLP-2 on the proliferation and apoptosis of intestinal epithelial cells in SBS rat models were evaluated. Exosomes were extracted from residual jejunum tissue of GLP-2 or vehicle treated SBS rats using ultracentrifugation method, and identified by nanoparticle trafficking analysis (NTA), transmission electron microscopy and western blotting. miRNA sequencing combined with qRT-PCR validation were used to identify differentially expressed miRNAs. miRNAs, which might be involved in proliferation and apoptosis of intestinal epithelial cells, were screened and further verified by miRNA functional experiments. Moreover, the proliferation-promoting and anti-apoptosis effects of GLP-2 on intestinal myofibroblasts, which expressing GLP-2 receptor, and whether GLP-2 could influence the content of miRNAs in the derived exosomes were studied. The downstream pathways were explored by miRNA function recovery experiment, luciferase reporter assay, pull down experiment, knockdown and overexpression of target gene and other experiments based on the bioinformatics prediction of miRNA target gene.Results: GLP-2 significantly promoted intestinal growth, facilitated the proliferation of intestinal crypt epithelial cells and inhibited the apoptosis of intestinal villi epithelial cells in type II SBS rats. GLP-2 significantly down-regulated exosomal miR-125a/b both in residual jejunums derived exosomes and in exosomes secreted by GLP-2R positive cells. Exosomal miR-125a/b was responsible for GLP-2 mediated intestinal epithelial cells proliferation promotion and apoptosis attenuation. miR-125a/b inhibited the proliferation and promotes apoptosis of intestinal epithelial cells by suppressing the myeloid cell leukemia-1 (MCL1).Conclusions: miR-125a/b shuttled by intestinal myofibroblasts derived exosomes regulate the proliferation and apoptosis of intestinal epithelial cells. GLP-2 treatment significantly decreases the level of miR-125a/b in the exosomes of intestinal myofibroblasts. miR-125a/b modulates the proliferation and apoptosis of intestinal epithelial cells by targeting the 3'UTR region of MCL1. Hence, this study indicates a novel mechanism of genetic exchange between cells in intestinal microenvironment.

Влияние глюкагоноподобных пептидов и оксинтомодулина на экскрецию ионов натрия почками у крыс

Maintaining sodium balance is ensured by a clear correspondence of salt intake through the gastrointestinal tract and its excretion mainly by the kidneys. It is of interest to evaluate the functional relationship of the digestive system and the kidneys and its contribution to maintaining a constant sodium concentration in the internal environment of the body. The aim of the study was to evaluate the participation of gut regulatory peptides, proglucagon derivatives, in the regulation of urinary sodium excretion. The diuretic and natriuretic effects of the intraperitoneal administration of oxyntomodulin, glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) at a dose of 1.5 nmol/kg were studied under normal and standardized (drink with 0.9% solution NaCl in a volume of 50 ml/kg) conditions of water-salt balance. An increase in urination and sodium excretion under the action of GLP-1 and a decrease in diuresis and natriuresis after injection of GLP-2 were shown. The effect of oxyntomodulin on kidney function has not been identified. The secretory response of the studied peptides to the load with oral administration of a 2.5% NaCl solution causing hypernatremia was evaluated: after 5 min an increase in GLP-1 concentration and a decrease in GLP-2 in the blood were observed, the level of oxyntomodulin did not change. The effect of peptides on the excretion of excess sodium and chloride by the kidneys during hypernatremia after oral and intraperitoneal administration of 2.5% NaCl solution (18 ml/kg) was studied. Injection of GLP-1 increased diuresis, excretion of sodium and chloride by the kidneys with an intraperitoneal NaCl load and accelerated the elimination of ions after oral loading. The antidiuretic and antinatriuretic effects of GLP-2 were revealed upon administration of the hormone with an oral NaCl load. Thus, derivatives of proglucagon, GLP-1 and GLP-2, are involved in the regulation of sodium balance. With an excessive intake of NaCl through the gastrointestinal tract, both the change of secretion of these regulatory peptides and their effects on urinary sodium excretion are oppositely directed.

Novel effect of glucagon-like peptide-2 for hepatocellular injury in a parenterally fed rat model of short bowel syndrome.

Short bowel syndrome (SBS) patients require long-term parenteral nutrition following massive bowel resection, which causes intestinal failure-associated liver disease (IFALD). Previous reports have shown that glucagon-like peptide-2 (GLP-2) resulted in the bowel adaptation for SBS. The aim of this study was to evaluate the effect of GLP-2 for IFALD in a parenterally fed rat model. Using rat, a catheter was placed in the jugular vein, and 90% small bowel resection (SBR) was performed. Animals were divided into three groups: SBR and total parenteral nutrition (TPN) (SBS/TPN group), SBR and TPN plus GLP-2 at 1µg/kg/h [SBS/TPN/GLP-2 (low) group], and SBR and TPN plus GLP-2 at 10µg/kg/h [SBS/TPN/GLP-2 (high) group]. On day 13, the liver was harvested and analyzed by using nonalcoholic fatty liver disease (NAFLD) score. Histologically, hepatic steatosis in the SBS/TPN group and SBS/TPN/GLP-2 (high) group was observed. Both steatosis and lobular inflammation score in the SBS/TPN/GLP-2 (low) group were significantly lower compared with those in the other two groups (p < 0.05). Active NAFLD score in the SBS/TPN/GLP-2 (low) group was significantly lower compared with that in the SBS/TPN/GLP-2 (high) group (p < 0.01). Low-dose GLP-2 intravenous administration improves hepatic steatosis of IFALD following in an SBS parenterally fed rat model.

GLP-2 and GIP exert separate effects on bone turnover: A randomized, placebo-controlled, crossover study in healthy young men

Glucagon-like peptide-2 (GLP-2) and glucose-dependent insulinotropic polypeptide (GIP) both inhibit bone resorption in humans but the underlying mechanisms are poorly understood. In vitro, GLP-2 activates the GIP-receptor (GIPR). Based on in vitro studies, we hypothesized that the antiresorptive effect of GLP-2 was mediated through the GIPR. This was tested using the selective GIPR-antagonist GIP(3-30)NH2. The study was a randomized, single-blinded, placebo-controlled, crossover study conducted at Hvidovre University Hospital, Denmark. Eight healthy young men were included and studied on four study days: GIP (200 μg), GLP-2 (800 μg), GIP(3-30)NH2 (800 pmol/kg/min) + GLP-2 (800 μg), and placebo. The main outcomes were bone resorption measured as collagen type 1 C-terminal telopeptide (CTX) and bone formation measured as procollagen type 1 N-terminal propeptide (P1NP). CTX (mean ± SEM) significantly decreased after both GIP (to 55.3 ± 6.3% of baseline at t = 90 min) and GLP-2 (to 60.5 ± 5.0% of baseline at t = 180 min). The maximal reduction in CTX after GIP(3-30)NH2 + GLP-2 (to 63.2 ± 3.1% of baseline) did not differ from GLP-2 alone (p = 0.95) nor did net AUC0-240 (-6801 ± 879%*min vs -6027 ± 648%*min, p = 0.56). At t = 30 min, GIP significantly (p < 0.0001) increased P1NP to 115.1 ± 2.2% of baseline compared with 103.1 ± 1.5% after placebo. Both GLP-2 and GIP(3-30)NH2 + GLP-2 significantly (p < 0.0001) decreased P1NP to 91.3 ± 1.1% and 88.1 ± 3.0% of baseline, respectively (at t = 45 min) compared with placebo. GIPR antagonism did not inhibit the GLP-2-induced reduction in bone resorption (CTX) in healthy young men. In contrast to GLP-2, GIP increased P1NP despite decreasing CTX indicating an uncoupling of bone resorption from formation. Thus, GLP-2 and GIP seem to exert separate effects on bone turnover in humans. ClinicalTrials.gov (NCT03159741).

Pharmacological evidence for the relationship between the NMDA receptor and nitric oxide pathway and the antidepressant-like effects of glucagon-like peptide-2 in the mouse forced-swim test.

We previously demonstrated that glucagon-like peptide-2 (GLP-2) exerted antidepressant-like effects in mice. The aim of the present study was to investigate the relationship between N-methyl-D-aspartate (NMDA) receptor-nitric oxide-cyclic guanosine monophosphate (NO-cGMP) pathway and the antidepressant-like effects of GLP-2 in the forced-swim test (FST) in mice. Intracerebroventricularly administered GLP-2 (3 μg/mouse) decreased the immobility time in the FST. The pretreatment of mice with l-arginine (750 mg/kg, i.p.), a substrate for nitric oxide synthase, sildenafil (5 mg/kg, i.p.), a phosphodiesterase 5 inhibitor, or d-serine (300 mg/kg, i.p.), a NMDA receptor co-agonist, inhibited the antidepressant-like effects of GLP-2 (3 μg/mouse) in the FST. Meanwhile, l-nitroarginine methyl ester (10 mg/kg, i.p.), a non-specific nitric oxide synthase (NOS) inhibitor, 7-nitroindazole (30 mg/kg, i.p.), a neuronal NOS inhibitor, methylene blue (10 mg/kg, i.p.), an inhibitor of both NOS and soluble guanylate cyclase (sGC), ODQ (30 pmol/site, i.c.v.), a sGC inhibitor, or MK-801 (0.05 mg/kg, i.p.), an NMDA receptor antagonist, in combination with a sub-effective dose of GLP-2 (1.5 μg/mouse) also decreased the immobility time in the FST. The present study provided evidence for the synergistic antidepressant-like effects of GLP-2 and inhibition of the NMDA receptor-l-arginine-NO-cGMP pathway in the FST, thereby contributing to our understanding of the mechanisms underlying the antidepressant-like effects of GLP-2.

Anti-inflammatory and antinociceptive activities of glucagon-like peptides: evaluation of their actions on serotonergic, nitrergic, and opioidergic systems.

Glucagon-like peptide-1 (GLP-1) and glucagon-like peptide-2 (GLP-2) are gut derived hormones. GLP-1 and GLP-2 were shown to have pleiotropic effects in intestinal and pancreatic diseases. We aimed to investigate the activities of GLP-1 and GLP-2 on nociception and inflammation in mice, involving their actions on serotonergic, nitrergic, and opioidergic systems. Antinociceptive and anti-inflammatory activities of intraperitoneally injected GLPs were evaluated in hotplate latency test, formalin-induced behavioral, and paw edema tests. Ondansetron, a selective 5-HT3 receptor antagonist; L-NAME, a NOS inhibitor; and naloxone, an opioid antagonist were injected to determine the mechanisms of antinociception and anti-inflammation. We also measured blood glucose levels and performed rotarod test in order to evaluate whether the hypoglycemic effect of GLP compounds or alterations in locomotor activity may affect the latency in hotplate test and activity in formalin test. GLP-1 (0.2mg/kg) and GLP-2 (0.05, 0.2mg/kg) significantly increased pain threshold. GLP-1 (0.2mg/kg) and GLP-2 (0.05, 0.1, 0.2mg/kg) significantly decreased formalin-induced licking and shaking behaviors. GLP-1 or GLP-2 showed no significant inhibitory action on formalin-induced swelling in paws of mice. Antinociceptive actions of GLP-1 and GLP-2 were significantly decreased with ondansetron and naloxone, and paw shaking behavior significantly increased with naloxone. GLP-1 and GLP-2 did not impair rotarod performance, and did not cause a significant hypoglycemic effect in our normoglycemic mice after rotarod test. These finding indicated that the antinociceptive and anti-inflammatory effect of GLP-1 was related to opioidergic system. Antinociceptive effect of GLP-2 was partially related to 5-HT3 serotonergic or opioidergic system in hotplate test. However, the anti-inflammatory effect of GLP-2 was not directly related to 5-HT3, NO or opioids.

Glucagon-Like Peptide-2 and the Enteric Nervous System Are Components of Cell-Cell Communication Pathway Regulating Intestinal Na+/Glucose Co-transport.

The Na+/glucose cotransporter 1, SGLT1 is the major route for transport of dietary glucose from the lumen of the intestine into absorptive enterocytes. Sensing of dietary sugars and artificial sweeteners by the sweet taste receptor, T1R2-T1R3, expressed in the enteroendocrine L-cell regulates SGLT1 expression in neighboring absorptive enterocytes. However, the mechanism by which sugar sensing by the enteroendocrine cell is communicated to the absorptive enterocytes is not known. Here, we show that glucagon-like peptide-2 (GLP-2) secreted from the enteroendocrine cell in response to luminal sugars regulates SGLT1 mRNA and protein expression in absorptive enterocytes, via the enteric neurons. Glucose and artificial sweeteners induced secretion of GLP-2 from mouse small intestine, which was inhibited by the sweet-taste receptor inhibitor, gurmarin. In wild type mice there was an increase in sugar-induced SGLT1 mRNA and protein abundance that was not observed in GLP-2 receptor knockout mice. GLP-2 receptor is expressed in enteric neurons, and not in absorptive enterocytes ruling out a paracrine effect of GLP-2. Electric field stimulation of the intestine resulted in upregulation of SGLT1 expression that was abolished by the nerve blocking agent tetrodotoxin. We conclude that GLP-2 and the enteric nervous system are components of the enteroendocrine-absorptive enterocyte communication pathway regulating intestinal glucose transport.

Quantitative perfusion assessment of intestinal anastomoses in pigs treated with glucagon-like peptide 2.

Despite exhaustive research and improvement of techniques, anastomotic leakage remains a frequent complication in gastrointestinal surgery. As leakage is associated with poor perfusion, reliable objective methods to assess anastomotic perfusion are highly demanded. In addition, such methods enable evaluation of interventions that may improve anastomotic perfusion. Glucagon-like peptide 2 (GLP-2) is an enteroendocrine hormone that regulates mid-gut perfusion. In the present study, we aimed to explore if quantitative perfusion assessment with indocyanine green (q-ICG) could detect an increase in porcine anastomotic perfusion after treatment with GLP-2. Nineteen pigs had two small bowel resections followed by anastomosis. Blinded to all investigators, animals were randomized to receive GLP-2 or placebo. Anastomotic perfusion was assessed at baseline, 30min after injection of GLP-2/placebo, and after 5days of treatment. Anastomotic strength and healing were evaluated by bursting pressure and histology. Q-ICG detected a significantly higher increase in anastomotic perfusion (p < 0.05) in animals treated with GLP-2, compared with placebo. No significant differences in anastomotic strength or healing were found. Q-ICG is a promising tool for perfusion assessment in gastrointestinal surgery and opens new opportunities in research of factors that may influence anastomotic healing, but further research is warranted to evaluate the effects of GLP-2 on anastomotic healing.