The prolonged effect of glucagon-like peptide 2 pretreatment on growth performance and intestinal development of weaned piglets

Background： Glucagon-like peptide 2 （GLP-2） is a potent epithelium-specific intestinal growth factor. The aim of this study was to demonstrate the prolonged effect of GLP-2 on the growth performance of weaned piglets. Forty piglets weaned at the age of 28 d with an average BW of 6.8 ＋ 0.4 kg were assigned to four treatments： （i） non- challenged control; （ii） LPS-challenged control; （iii） LPS ＋ low GLP-2; and （iv） LPS ＋ high GLP-2. Piglets in groups （i）, （ii）, and （iv） were s.c. injected with PBS supplemented with human [Gly2]GLP-21-34 at doses of 0, 2 and 10 nmol/kg BW per day for seven consecutive days. BW, gain：feed ratio （G：F）, and plasma GLP-2 levels were determined on d 0 7, and 14 after weaning. Piglets were challenged with i.p. administration of Escherichia coil lipopolysaccharide （LPS） at a dose of 100 pg/kg on d 14 to induce intestinal damage. Twenty-four hours later, intestinal tract samples were collected to assess intestinal morphology and quantify enzyme activity. Results： Plasma GLP-2 levels decreased after weaning, but in the high GLP-2 group, plasma GLP-2 was maintained on d 7 and even increased to a level higher than the preweaning level on d ]4 （P 〈 0.05）. High GLP-2 treatment significantly increased the duodenal, jejunal and ileal weight, as well as the gross weight of the small intestine （SI）, and the SI weight index （P 〈 0.05）. LPS caused villous atrophy and disrupted intestinal morphology in the duodenum, jejunum and ileum. GLP-2 also significantly increased the villus height and the villus height/crypt depth ratio （VCR） of the duodenum, jejunum, and ileum （P 〈 0.05）. Histological examination revealed that in GLP-2-treated groups, the integrity of the villus was maintained, and the villus was protected against LPS-induced damage. GLP-2 significantly increased the activity of alkaline phosphatase （AKP）, y-glutamyltranspeptidase （y-G-i-）, and pancreatic lipase in the duodenum and jejunum （P 〈 0.05）. GLP-2 treatment also significantly increased the average daily gain （ADG） and G：F of piglets at 0 to 7, 7 to 14, as well as 0 to14 d （P 〈 0.05）, resulting in a significant increase of final 8W in high GLP-2 pigs （P = 0.016）. Conclusions： Exogenous GLP-2 improved the growth of weaned piglets and protected them against LPS-induced intestinal damage. These effects may be due to the ability of GLP-2 to promote the secretion of endogenous GLP-2 to stimulate the small intestinal development.

A Retrospective Analysis of Glucagon-Like Peptide 1 Receptor Agonists in Treating Type 2 Diabetes Mellitus Complicated by Nonalcoholic Fatty Liver Disease

Background: The objective of this study was to compare and analyze the variations in clinical indices before and after treatment of type 2 mellitus (T2DM) combined with nonalcoholic fatty liver disease (NAFLD) that were treated with glucagon-like peptide 1 receptor agonists (GLP-1RAs). Methods: The electronic medical record system was utilized to search for a total of 16 patients with type 2 diabetes complicated by NAFLD who were hospitalized at the First Affiliated Hospital of Yangtze University from October 2022 to April 2023 and treated with GLP-1RA for the first time. The clinical indices were compared before and after 12 weeks of treatment with GLP-1RA. Results: The liver-spleen CT ratio (L/S), alanine aminotransferase (ALT), gamma-glutamyltransferase (GGT), total cholesterol (TC), triglyceride (TG), and low-density lipoprotein cholesterol (LDL-C) in all patients treated with GLP-1RA after 12 weeks were significantly different (P 0.05). The patients were categorized into two groups based on the types of GLP-1RAs. The changes in L/S, TC, TG, and LDL-C in the long-acting group after treatment were statistically significant (P Conclusions: GLP-1RAs can improve liver function, regulate lipid metabolism, and reduce the severity of fatty liver in patients with T2DM complicated by NAFLD, which demonstrates the importance of clinical applications.

Glucagon-like-peptide-1 receptor agonists and the management of type 2 diabetes-backwards and forwards

This editorial is stimulated by the article by Alqifari et al published in the World Journal of Diabetes(2024).Alqifari et al focus on practical advice for the clinical use of glucagon-like-peptide-1(GLP-1)receptor agonists(GLP-1RAs)in the management of type 2 diabetes and this editorial provides complementary information.We initially give a brief historical perspective of the development of GLP-1RAs stimulated by recognition of the‘incretin effect’,the substantially greater insulin increase to enteral when compared to euglycaemic intravenous glucose,and the identification of the incretin hormones,GIP and GLP-1.In addition to stimulating insulin,GLP-1 reduces postprandial glucose levels by slowing gastric emptying.GLP-1RAs were developed because native GLP-1 has a very short plasma half-life.The majority of current GLP-1RAs are administered by subcutaneous injection once a week.They are potent in glucose lowering without leading to hypoglycaemia,stimulate weight loss in obese individuals and lead to cardiovascular and renal protection.The landscape in relation to GLP-1RAs is broadening rapidly,with different formulations and their combination with other peptides to facilitate both glucose lowering and weight loss.There is a need for more information relating to the effects of GLP-1RAs to induce gastrointestinal symptoms and slow gastric emptying which is likely to allow their use to become more effective and personalised.

Glucagon-like peptide 1 receptor activation:anti-inflammatory effects in the brain

The glucagon-like peptide 1 is a pleiotropic hormone that has potent insulinotropic effects and is key in treating metabolic diseases such as diabetes and obesity.Glucagon-like peptide 1 exerts its effects by activating a membrane receptor identified in many tissues,including diffe rent brain regions.Glucagon-like peptide 1 activates several signaling pathways related to neuroprotection,like the support of cell growth/survival,enhancement promotion of synapse formation,autophagy,and inhibition of the secretion of proinflammatory cytokines,microglial activation,and apoptosis during neural morphogenesis.The glial cells,including astrocytes and microglia,maintain metabolic homeostasis and defe nse against pathogens in the central nervous system.After brain insult,microglia are the first cells to respond,followed by reactive astrocytosis.These activated cells produce proinflammato ry mediators like cytokines or chemokines to react to the insult.Furthermore,under these circumstances,mic roglia can become chro nically inflammatory by losing their homeostatic molecular signature and,consequently,their functions during many diseases.Several processes promote the development of neurological disorders and influence their pathological evolution:like the formation of protein aggregates,the accumulation of abnormally modified cellular constituents,the formation and release by injured neurons or synapses of molecules that can dampen neural function,and,of critical impo rtance,the dysregulation of inflammato ry control mechanisms.The glucagonlike peptide 1 receptor agonist emerges as a critical tool in treating brain-related inflammatory pathologies,restoring brain cell homeostasis under inflammatory conditions,modulating mic roglia activity,and decreasing the inflammato ry response.This review summarizes recent advances linked to the anti-inflammato ry prope rties of glucagon-like peptide 1 receptor activation in the brain related to multiple sclerosis,Alzheimer’s disease,Parkinson’s disease,vascular dementia,or chronic migraine.

Role of gut-liver axis and glucagon-like peptide-1 receptor agonists in the treatment of metabolic dysfunction-associated fatty liver disease

Metabolic dysfunction-associated fatty liver disease(MAFLD)is a hepatic manifestation of the metabolic syndrome.It is one of the most common liver diseases worldwide and shows increasing prevalence rates in most countries.MAFLD is a progressive disease with the most severe cases presenting as advanced fibrosis or cirrhosis with an increased risk of hepatocellular carcinoma.Gut microbiota play a significant role in the pathogenesis and progression of MAFLD by disrupting the gut-liver axis.The mechanisms involved in maintaining gut-liver axis homeostasis are complex.One critical aspect involves preserving an appropriate intestinal barrier permeability and levels of intestinal lumen metabolites to ensure gutliver axis functionality.An increase in intestinal barrier permeability induces metabolic endotoxemia that leads to steatohepatitis.Moreover,alterations in the absorption of various metabolites can affect liver metabolism and induce liver steatosis and fibrosis.Glucagon-like peptide-1 receptor agonists(GLP-1 RAs)are a class of drugs developed for the treatment of type 2 diabetes mellitus.They are also commonly used to combat obesity and have been proven to be effective in reversing hepatic steatosis.The mechanisms reported to be involved in this effect include an improved regulation of glycemia,reduced lipid synthesis,β-oxidation of free fatty acids,and induction of autophagy in hepatic cells.Recently,multiple peptide receptor agonists have been introduced and are expected to increase the effectiveness of the treatment.A modulation of gut microbiota has also been observed with the use of these drugs that may contribute to the amelioration of MAFLD.This review presents the current understanding of the role of the gutliver axis in the development of MAFLD and use of members of the GLP-1 RA family as pleiotropic agents in the treatment of MAFLD.

Impact of glucagon-like peptide receptor agonists on endoscopy and its preoperative management: Guidelines, challenges, and future directions

Glucagon-like peptide receptor agonists(GLP-1RA)are used to treat type 2 diabetes mellitus and,more recently,have garnered attention for their effect-iveness in promoting weight loss.They have been associated with several gastrointestinal adverse effects,including nausea and vomiting.These side effects are presumed to be due to increased residual gastric contents.Given the potential risk of aspiration and based on limited data,the American Society of Anesthesi-ologists updated the guidelines concerning the preoperative management of patients on GLP-1RA in 2023.They included the duration of mandated cessation of GLP-1RA before sedation and usage of“full stomach”precautions if these medications were not appropriately held before the procedure.This has led to additional challenges,such as extended waiting time,higher costs,and increased risk for patients.In this editorial,we review the current societal guidelines,clinical practice,and future directions regarding the usage of GLP-1RA in patients undergoing an endoscopic procedure.

Cardioprotective effects of glucagon-like peptide 1 receptor agonists in heart failure: Myth or truth?

Therapy with glucagon-like peptide 1(GLP1)receptor agonists has raised great interest for its beneficial cardiovascular effects in preventing atherosclerosis and heart failure-related outcomes.However,while evidence about atherosclerosis consistently suggests a cardioprotective potential with class effect,controversies remain on its impact on heart failure.GLP1 receptor agonists appear to prevent hospitalization for new-onset heart failure and reduce symptoms in heart failure with preserved ejection fraction(as demonstrated by the recent STEP-HFpEF Trial).Still,GLP1 agonism has resulted in neutral or even harmful effects in patients with established heart failure with reduced ejection fraction(the LIVE trial).GLP1 receptor agonists benefit the cardiovascular system indirectly through their marked metabolic effects(improved weight management,glycemic control,blood pressure,systemic and tissue inflammation),while direct effects on the heart have been questioned.Nonetheless,weight loss alone achieved through GLP1 receptor agonists has failed in improving left ventricular functions.Tirzepatide is a dual agonist of GLP1 and glucose-dependent insulinotropic polypeptide,representing an innovative treatment option in diabetes with a major impact on weight loss and promising cardiovascular benefits.Whether this class of therapies is going to change the history of heart failure is an ongoing debate.

Postprandial glucagon-like peptide 1 secretion is associated with urinary albumin excretion in newly diagnosed type 2 diabetes patients

BACKGROUND Microalbuminuria is an early and informative marker of diabetic nephropathy.Our study found that microalbuminuria developed in patients with newly diagnosed type 2 diabetes mellitus(T2DM).AIM To investigate the association between glucagon-like peptide 1(GLP-1)and microalbuminuria in newly diagnosed T2DM patients.METHODS In total,760 patients were recruited for this cross-sectional study.The GLP-1 levels during a standard meal test and urinary albumin-creatinine ratio(UACR)were determined.RESULTS Patients with microalbuminuria exhibited lower GLP-1 levels at 30 min and 120 min during a standard meal test than patients with normal albuminuria(30 min GLP-1,16.7±13.3 pmol vs 19.9±15.6 pmol,P=0.007;120 min GLP-1,16.0±14.1 pmol vs 18.4±13.8 pmol,P=0.037).The corresponding area under the curve for active GLP-1(AUCGLP-1)was also lower in microalbuminuria patients(2257,1585 to 3506 vs 2896,1763 to 4726,pmol×min,P=0.003).Postprandial GLP-1 levels at 30 min and 120 min and AUCGLP-1 were negatively correlated with the UACR(r=0.159,r=0.132,r=0.206,respectively,P<0.001).The prevalence of microalbuminuria in patients with newly diagnosed T2DM was 21.7%,which decreased with increasing quartiles of AUCGLP-1 levels(27.4%,25.3%,18.9%and 15.8%).After logistic regression analysis adjusted for sex,age,hemoglobin A1c,body mass index,systolic blood pressure,estimated glomerular filtration rate,homeostasis model assessment of insulin resistance,AUC_(glucose)and AUC_(glucagon)patients in quartile 4 of the AUCGLP-1 presented a lower risk of microalbuminuria compared with the patients in quartile 1(odds ratio=0.547,95%confidence interval:0.325-0.920,P=0.01).A consistent association was also found between 30 min GLP-1 or 120 min GLP-1 and microalbuminuria.CONCLUSION Postprandial GLP-1 levels were independently associated with microalbuminuria in newly diagnosed Chinese T2DM patients.

Effects of glucagon-like peptide-1 receptor agonists on glucose excursion and inflammation in overweight or obese type 2 diabetic patients

BACKGROUND Currently,the lack of comparative studies between weekly and daily formulations of glucagon-like peptide-1 receptor agonists(GLP-1RAs)for glucose excursion is worth investigation.AIM To investigate the effects of weekly and daily formulations of GLP-1RA on glucose excursion and inflammation in overweight and obese patients with type 2 diabetes.METHODS Seventy patients with type 2 diabetes mellitus who were treated at our hospital between January 2019 and January 2022 were enrolled in this retrospective analysis.All patients were treated with metformin.We evaluated changes in blood glucose levels and a series of important indicators in patients before and after treatment with either a weekly or daily preparation of GLP-1RA(group A;n=33 and group B;n=37).RESULTS The degree of decrease in the levels of fasting blood glucose,mean blood glucose,mean amplitude of glycemic excursions,total cholesterol,triglycerides,tumor necrosis factor-α,interleukin-6,and high-sensitivity C-reactive protein after treatment in group A was higher than that in group B(P<0.05),whereas the 2-h postprandial blood glucose levels decreased more so in group B than in group A(P<0.001).However,there were no statistically significant differences in the levels of glycated hemoglobin,standard deviation of blood glucose,coefficient of variation,absolute mean of daily differences,percentage of time with 3.9 mmol/L<glucose<10 mmol/L,and high-and low-density lipoproteins between the two groups(P>0.05).The incidence of adverse reactions was significantly lower in group A than in group B(P<0.05).CONCLUSION The effect of the weekly preparation of GLP-1RA in controlling blood glucose levels in the patients,suppressing inflammation,and reducing adverse reactions was significantly higher than that of the daily preparations,which is worthy of clinical promotion.

Type-2 Diabetes Mellitus and Glucagon-Like Peptide-1 Receptor toward Predicting Possible Association

Aim: This study aimed to investigate the effect of non-synonymous SNPs (nsSNPs) of the Glucagon-like peptide-1 Receptor (GLP-1R) gene in protein function and structure using different computational software. Introduction: The GLP1R gene provides the necessary instruction for the synthesis of the insulin hormones which is needed for glucose catabolism. Polymorphisms in this gene are associated with diabetes. The protein is an important drug target for the treatment of type-2 diabetes and stroke. Material and Methods: Different nsSNPs and protein-related sequences were obtained from NCBI and ExPASY database. Gene associations and interactions were predicted using GeneMANIA software. Deleterious and damaging effects of nsSNPs were analyzed using SIFT, Provean, and Polyphen-2. The association of the nsSNPs with the disease was predicted using SNPs & GO software. Protein stability was investigated using I-Mutant and MUpro software. The structural and functional impact of point mutations was predicted using Project Hope software. Project Hope analyzes the mutations according to their size, charge, hydrophobicity, and conservancy. Results: The GLP1R gene was found to have an association with 20 other different genes. Among the most important ones is the GCG (glucagon) gene which is also a trans membrane protein. Overall 7229 variants were seen, and the missense variants or nsSNPs (146) were selected for further analysis. The total number of nsSNPs obtained in this study was 146. After being subjected to SIFT software (27 Deleterious and 119 Tolerated) were predicted. Analysis with Provean showed that (20 deleterious and 7 neutral). Analysis using Polyphen-2 revealed 17 probably damaging, 2 possibly damaging and 1 benign nsSNPs. Using two additional software SNPs & GO and PHD-SNPs showed that 14 and 17 nsSNPs had a disease effect, respectively. Project Hope software predicts the effect of the 14 nsSNPs on the protein function due to differences in charge, size, hydrophobicity, and conservancy between the wild and mutant types. Conclusion: In this study, the 14 nsSNPs which were highly affected the protein function. This protein is providing the necessary instruction for the synthesis of the insulin hormones which is needed for glucose catabolism. Polymorphisms in this gene are associated with diabetes and also affect the treatment of diabetic patients due to the fact that the protein acts as an important drug target.

Exploration of cyclooxygenase-2 inhibitory peptides from walnut dreg proteins based on in silico and in vitro analysis

Walnut dreg protein hydrolysates(WDPHs)exhibit a variety of biological activities,however,the cyclooxygenase-2(COX-2)inhibitory peptide of WDPHs remain unclear.The aim of this study was to rapidly screen for such peptides in WDPHs through a combination of in silico and in vitro analysis.In total,1262 peptide sequences were observed by nano liquid chromatography/tandem mass spectrometry(nano LC-MS/MS)and 4 novel COX-2 inhibitory peptides(AGFP,FPGA,LFPD,and VGFP)were identified.Enzyme kinetic data indicated that AGFP,FPGA,and LFPD displayed mixed-type COX-2 inhibition,whereas VGFP was a non-competitive inhibitor.This is mainly because the peptides form hydrogen bonds and hydrophobic interactions with residues in the COX-2 active site.These results demonstrate that computer analysis combined with in vitro evaluation allows for rapid screening of COX-2 inhibitory peptides in walnut protein dregs.

Fixed-ratio combinations of basal insulin and glucagon-like peptide-1 receptor agonists as a promising strategy for treating diabetes

The maintenance of appropriate glycemic control is important for the prevention of diabetic complications in people with type 2 diabetes(T2D). Numerous oral antidiabetic drugs are now clinically available, but in particular, the introduction of injection regimens using insulin and/or glucagon-like peptide-1 receptor agonist(GLP-1RA)s represents promising step-up options for oral antidiabetic drug treatment. The recently licensed fixed-ratio combination(FRC) products,which comprise basal insulin and a GLP-1RA, have potent anti-hyperglycemic effects and reduce the undesirable side-effects of each component, such as body weight gain, hypoglycemia, and gastrointestinal symptoms. Two FRCs-insulin degludec/Liraglutide and insulin glargine/Lixisenatide-are now clinically available and, to date, several phase Ⅱ/Ⅲ trials have been conducted in particular groups of subjects with T2D. However, their utility in real-world clinical settings is of interest for most clinicians. Recently reported real-world clinical trials of these two FRCs in various situations have demonstrated their efficacy regarding glycemic control and the quality of life of people with T2D. Their long-term safety and efficacy require confirmation, but a treatment strategy that includes an FRC may be compatible with the concept of “well-balanced” therapy in certain groups of patients with T2D who have inadequate glycemic control.

Potential therapeutic targets for nonalcoholic fatty liver disease:Glucagon-like peptide 1

Nonalcoholic fatty liver disease(NAFLD)is the most rapidly growing contributor to liver mortality and morbidity.Hepatocellular injury in nonalcoholic steatohepatitis(NASH)is caused by an increase in metabolic substrates(glucose,fructose,and fatty acids),leading fatty acids to participate in pathways that cause cellular injury and a poor response to injury.The pathogenesis of this disease is largely associated with obesity,type 2 diabetes,and increasing age.To date,there are no Food and Drug Administration-approved treatments for NAFLD/NASH or its associated fibrosis.Since one of the pathogenic drivers of NASH is insulin resistance,therapies approved for the treatment of type 2 diabetes are being evaluated in patients with NASH.Currently,the glucagon-like peptide-1 receptor agonist(GLP-1RA)semaglutide is a safe,well-studied therapeutic for NAFLD/NASH patients.Existing research demonstrates that semaglutide can increase the resolution of NASH but not improve fibrosis.However,improving the fibrosis of NAFLD is the only way to improve the long-term prognosis of NAFLD.Given the complex pathophysiology of NASH,combining therapies with complementary mechanisms may be beneficial.Researchers have conducted trials of semaglutide in combination with antifibrotic drugs.However,the results have not fully met expectations,and it cannot be ruled out that the reason is the short trial time.We should continue to pay increasing attention to GLP-1RAs.

Effects of glucagon-like peptide 1 analogs in combination with insulin on myocardial infarct size in rats with type 2 diabetes mellitus

AIM To evaluate the effects of glucagon-like peptide-1 analogs(GLP-1 a) combined with insulin on myocardial ischemiareperfusion injury in diabetic rats.METHODS Type 2 diabetes mellitus(T2 DM) was induced in maleWistar rats with streptozotocin(65 mg/kg) and verified using an oral glucose tolerance test. After anesthesia, the left coronary artery was occluded for 40 min followed by 80 min reperfusion. Blood glucose level was measured during surgery. Rats were randomized into six groups as follows:(1) control rats;(2) insulin(0.1 U/kg) treated rats prior to ischemia;(3) insulin(0.1 U/kg) treated rats at reperfusion;(4) GLP-1 a(140 mg/kg) treated rats prior to ischemia;(5) GLP-1 a(140 mg/kg) treated rats at reperfusion; and(6) rats treated with GLP-1 a(140 mg/kg) prior to ischemia plus insulin(0.1 U/kg) at reperfusion. Myocardial area at risk and infarct size was measured planimetrically using Evans blue and triphenyltetrazolium chloride staining, respectively.RESULTS There was no significant difference in the myocardial area at risk among groups. Insulin treatment before ischemia resulted in a significant increase in infarct size(34.7% ± 3.4% vs 18.6% ± 3.1% in the control rats, P < 0.05). Post-ischemic administration of insulin or GLP-1 a had no effect on infarct size. However, pre-ischemic administration of GLP-1 a reduced infarct size to 12% ± 2.2%(P < 0.05). The maximal infarct size reduction was observed in the group treated with GLP-1 a prior to ischemia and insulin at reperfusion(8% ± 1.6%, P < 0.05 vs the control and GLP-1 a alone treated groups).CONCLUSION GLP-1 a pre-administration results in myocardial infarct size reduction in rats with T2 DM. These effects are maximal in rats treated with GLP-1 a pre-ischemia plus insulin at reperfusion.

Effects of Glucagon-Like Peptide 1 on PDX-1, PAX-6 and NKx2.2 Gene Expressions in Isolated Pancreatic Islets

Objective： To observe the effect of glucagon-like peptide 1 （GLP-1） on the gene expressions of transcription factors （PDX-1, PAX-6 and NKx2.2 ） in freshly isolated rat pancreatic islets and investigate the associated physiological and therapeutic implication of GLP-1. Methods： The isolated rat islets were incubated with 10 nmol/L GLP-1 for 1, 3 and 5 days, respectively. Total cellular RNA was extracted and the expressions of PDX-1, PAX-6 and NKx2.2 gene were detected by semiquantity RT-PCR. Results： Compared with the control group, the PDX-1, PAX-6 and NKx2.2 gene expressions were significantly increased after co-cultured with GLP-1 for 1 day （P 〈 0.05）. The effect was shown in a time-dependent manner. All three gene expressions reached the peak on the 5th day. Conclusion： GLP-1 can improve the function of pancreatic islet by regulating the gene expressions of transcription factors in β cells.

Uncoupling protein 2 regulates glucagon-like peptide-1 secretion in L-cells

AIM:To investigate whether uncoupling protein 2(UCP2) affects oleic acid-induced secretion of glucagonlike peptide-1(GLP-1) in L-cells.METHODS:mRNA and protein expression of UCP2 were analyzed in human NCI-H716 cells,which serve as a model for enteroendocrine L-cells,by quantitative reverse transcription-polymerase chain reaction and Western blotting before and after treatment with oleic acid.Localization of UCP2 and GLP-1 in NCI-H716 cells was assessed by immunofluorescence labeling.NCI-H716 cells were transiently transfected with a small interfering RNA(siRNA) that targets UCP2(siUCP2) or with a nonspecific siRNA using Lipofectamine 2000.The concentrations of bioactive GLP-1 in the medium were measured by enzyme linked immunosorbent assay.RESULTS:Both GLP-1 and UCP2 granules were expressed mainly in the cytoplasm of NCI-H716 cells.NCI-H716 cells that secreted GLP-1 also expressed UCP2.Time-course experiments revealed that release of GLP-1 from NCI-H716 cells into the medium reached a maximum at 120 min and remained stable until at least 180 min after treatment with oleic acid(the level of GLP-1 increased about 2.3-fold as compared with the level of GLP-1 in the control cells,P < 0.05).In an experiment to determine dose dependence,stimulation of NCI-H716 cells with ≤ 8 mmol oleic acid led to a concentration-dependent release of GLP-1 into the medium;10 mmol oleic acid diminished the release of GLP-1.Furthermore,GLP-1 secretion induced by oleic acid from NCI-H716 cells that were transfected with siUCP2 decreased to 41.8%,as compared with NCI-H716 cells that were transfected with a non-specific siRNA(P < 0.01).CONCLUSION:UCP2 affected GLP-1 secretion induced by oleic acid.UCP2 plays an important role in L-cell secretion that is induced by free fatty acids.

Glucagon-like peptide-2 modulates the nitrergic neurotransmission in strips from the mouse gastric fundus

AIM To investigate whether glucagon-like peptide-2(GLP-2) influences the neurally-induced responses in gastric strips from mice, since no data are available. METHODS For functional experiments, gastric fundal strips were mounted in organ baths containing Krebs-Henseleit solution. Mechanical responses were recorded via forcedisplacement transducers, which were coupled to a polygraph for continuous recording of isometric tension. Electrical field stimulation(EFS) was applied via two platinum wire rings through which the preparationwas threaded. The effects of GLP-2(2 and 20 nmol/L) were evaluated on the neurally-induced contractile and relaxant responses elicited by EFS. Neuronal nitric oxide synthase(n NOS) enzyme was evaluated by immunohistochemistry.RESULTS In the functional experiments, electrical field stimulation(EFS, 4-16 Hz) induced tetrodotoxin(TTX)-sensitive contractile responses, which were reduced in amplitude by GLP-2(P < 0.05). In the presence of the nitric oxide(NO) synthesis inhibitor L-NNA, GLP-2 no longer influenced the neurally-evoked contractile responses(P > 0.05). The direct smooth muscle response to methacholine was not influenced by GLP-2(P > 0.05). In the presence of guanethidine and carbachol, the addition of GLP-2 to the bath medium evoked TTX-sensitive relaxant responses that were unaffected by L-NNA(P > 0.05). EFS induced a fast NO-mediated relaxation, whose amplitude was enhanced in the presence of the hormone(P < 0.05). Immunohistochemical experiments showed a significant increase(P < 0.05) in n NOS immunoreactivity in the nerve structures after GLP-2 exposure. CONCLUSION The results demonstrate that in gastric fundal strips, GLP-2 influences the amplitude of neurally-induced responses through the modulation of the nitrergic neurotransmission and increases n NOS expression.

Glucagon-like peptide-2 analogues for Crohn’s disease patients with short bowel syndrome and intestinal failure

Short bowel syndrome(SBS)with intestinal failure(IF)is a rare but severe complication of Crohn’s disease(CD),which is the most frequent benign condition that leads to SBS after repeated surgical resections,even in the era of biologics and small molecules.Glucagon-like peptide-2 analogues have been deeply studied recently for the treatment of SBS-IF.These drugs have a significant intestinotrophic effect and the potential to reduce the chronic dependence of SBSIF patients on parenteral support or nutrition.Teduglutide has been approved for the treatment of SBS-IF,and apraglutide is currently in clinical development.The use of these drugs was examined with a focus on their use in CD patients.

Protective effects of peptide KSPLY derived from Hericium erinaceus on H_(2)O_(2)-induced oxidative damage in HepG2 cells

Reactive oxygen species(ROS)-induced oxidative damage is strongly associated with the pathogenesis of chronic diseases,and natural antioxidant peptides have good abilities of scavenging ROS.The antioxidant activity of peptide Lys-Ser-Pro-Leu-Tyr(KSPLY)derived from Hericium erinaceus remains unclear.In the present study,the antioxidant effect and mechanism of KSPLY on H_(2)O_(2)-induced oxidative damage in HepG2 cells were investigated.The results indicated that KSPLY exhibited the antioxidant capacity in H_(2)O_(2)-induced HepG2 cells by enhancing superoxide dismutase(SOD),glutathione peroxidase(GSH-Px),and catalase(CAT)activities.In comparison with the H_(2)O_(2)-treated damage group,the apoptosis rate,ROS level,and malondialdehyde(MDA)content of HepG2 cells treated with KSPLY were significantly decreased.The H.erinaceus-derived peptide KSPLY pretreatment promoted the expression of detoxification and antioxidant enzymes via the Keap1/Nrf2 signal pathway,thereby inhibiting the generation of ROS and MDA.In conclusion,the H.erinaceus-derived peptide KSPLY effectively protected HepG2 cells against H_(2)O_(2)-induced oxidative damage,and it provided a theoretical basis for the further development of new natural antioxidants.

A matrix metalloproteinase-responsive hydrogel system controls angiogenic peptide release for repair of cerebral ischemia/reperfusion injury

Vascular endothelial growth factor and its mimic peptide KLTWQELYQLKYKGI(QK)are widely used as the most potent angiogenic factors for the treatment of multiple ischemic diseases.However,conventional topical drug delivery often results in a burst release of the drug,leading to transient retention(inefficacy)and undesirable diffusion(toxicity)in vivo.Therefore,a drug delivery system that responds to changes in the microenvironment of tissue regeneration and controls vascular endothelial growth factor release is crucial to improve the treatment of ischemic stroke.Matrix metalloproteinase-2(MMP-2)is gradually upregulated after cerebral ischemia.Herein,vascular endothelial growth factor mimic peptide QK was self-assembled with MMP-2-cleaved peptide PLGLAG(TIMP)and customizable peptide amphiphilic(PA)molecules to construct nanofiber hydrogel PA-TIMP-QK.PA-TIMP-QK was found to control the delivery of QK by MMP-2 upregulation after cerebral ischemia/reperfusion and had a similar biological activity with vascular endothelial growth factor in vitro.The results indicated that PA-TIMP-QK promoted neuronal survival,restored local blood circulation,reduced blood-brain barrier permeability,and restored motor function.These findings suggest that the self-assembling nanofiber hydrogel PA-TIMP-QK may provide an intelligent drug delivery system that responds to the microenvironment and promotes regeneration and repair after cerebral ischemia/reperfusion injury.