Macrophage modulation with dipeptidyl peptidase-4 inhibitors:A new frontier for treating diabetic cardiomyopathy?

This editorial introduces the potential of targeting macrophage function for diabetic cardiomyopathy(DCM)treatment by dipeptidyl peptidase-4(DPP-4)inhibitors.Zhang et al studied teneligliptin,a DPP-4 inhibitor used for diabetes management,and its potential cardioprotective effects in a diabetic mouse model.They suggested teneligliptin administration may reverse established markers of DCM,including cardiac hypertrophy and compromised function.It also inhibited the NLRP3 inflammasome and reduced inflammatory cytokine production in diabetic mice.Macrophages play crucial roles in DCM pathogenesis.Chronic hyperglycemia disturbs the balance between pro-inflammatory(M1)and antiinflammatory(M2)macrophages,favoring a pro-inflammatory state contributing to heart damage.Here,we highlight the potential of DPP-4 inhibitors to modulate macrophage function and promote an anti-inflammatory environment.These compounds may achieve this by elevating glucagon-like peptide-1 levels and potentially inhibiting the NLRP3 inflammasome.Further studies on teneligliptin in combination with other therapies targeting different aspects of DCM could be suggested for developing more effective treatment strategies to improve cardiovascular health in diabetic patients.

DPP-4 inhibitors and GLP-1RAs:cardiovascular safety and benefits

Glucagon-like peptide-1 receptor agonists(GLP-1RAs)and dipeptidyl peptidase-4 inhibitors are commonly used treatments for patients with type 2 diabetes mellitus(T2DM).Both anti-diabetic treatments function by playing key modulatory roles in the incretin system.Though these drugs have been deemed effective in treating T2DM,the Food and Drug Administration(FDA)and some members of the scientific community have questioned the safety of these therapeutics relative to important cardiovascular endpoints.As a result,since 2008,the FDA has required all new drugs for glycemic control in T2DM patients to demonstrate cardiovascular safety.The present review article strives to assess the safety and benefits of incretin-based therapy,a new class of antidiabetic drug,on the health of patient cardiovascular systems.In the process,this review will also provide a physiological overview of the incretin system and how key components function in T2DM.

Dipeptidyl peptidase-4 inhibitor for steroid-induced diabetes

The addition of the dipeptidyl peptidase-4 (DDP-4) inhibitor has been reported to achieve greater improvements in glucose metabolism with fewer adverse events compared to increasing the metformin dose in type 2 diabetic patients. We present a patient with steroid-induced diabetes whose blood glucose levels were ameliorated by the use of the DPP-4 inhibitor, showing that the DPP-4 inhibitors may be an effective and safe oral anti-diabetic drug for steroid-induced diabetes.

Cardiovascular efficacy and safety of dipeptidyl peptidase-4 inhibitors:A meta-analysis of cardiovascular outcome trials

BACKGROUND Dipeptidyl peptidase-4(DPP-4)inhibitors are a generally safe and well tolerated antidiabetic drug class with proven efficacy in type 2 diabetes mellitus(T2DM).Recently,a series of large,randomized controlled trials(RCTs)addressing cardiovascular outcomes with DPP-4 inhibitors have been published.AIM To pool data from the aforementioned trials concerning the impact of DPP-4 inhibitors on surrogate cardiovascular efficacy outcomes and on major cardiac arrhythmias.METHODS We searched PubMed and grey literature sources for all published RCTs assessing cardiovascular outcomes with DPP-4 inhibitors compared to placebo until October 2020.We extracted data concerning the following“hard”efficacy outcomes:fatal and non-fatal myocardial infarction,fatal and non-fatal stroke,hospitalization for heart failure,hospitalization for unstable angina,hospitalization for coronary revascularization and cardiovascular death.We also extracted data regarding the risk for major cardiac arrhythmias,such as atrial fibrillation,atrial flutter,ventricular fibrillation and ventricular tachycardia.RESULTS We pooled data from 6 trials in a total of 52520 patients with T2DM assigned either to DPP-4 inhibitor or placebo.DPP-4 inhibitors compared to placebo led to a non-significant increase in the risk for fatal and non-fatal myocardial infarction[risk ratio(RR)=1.02,95%CI:0.94-1.11,I2=0%],hospitalization for heart failure(RR=1.09,95%CI:0.92-1.29,I2=65%)and cardiovascular death(RR=1.02,95%CI:0.93-1.11,I2=0%).DPP-4 inhibitors resulted in a non-significant decrease in the risk for fatal and non-fatal stroke(RR=0.96,95%CI:0.85-1.08,I2=0%)and coronary revascularization(RR=0.99,95%CI:0.90-1.09,I2=0%),Finally,DPP-4 inhibitors demonstrated a neutral effect on the risk for hospitalization due to unstable angina(RR=1.00,95%CI:0.85-1.18,I2=0%).As far as cardiac arrhythmias are concerned,DPP-4 inhibitors did not significantly affect the risk for atrial fibrillation(RR=0.95,95%CI:0.78-1.17,I2=0%),while they were associated with a significant increase in the risk for atrial flutter,equal to 52%(RR=1.52,95%CI:1.03-2.24,I2=0%).DPP-4 inhibitors did not have a significant impact on the risk for any of the rest assessed cardiac arrhythmias.CONCLUSION DPP-4 inhibitors do not seem to confer any significant cardiovascular benefit for patients with T2DM,while they do not seem to be associated with a significant risk for any major cardiac arrhythmias,except for atrial flutter.Therefore,this drug class should not be the treatment of choice for patients with established cardiovascular disease or multiple risk factors,except for those cases when newer antidiabetics(glucagon-like peptide-1 receptor agonists and sodium-glucose cotransporter-2 inhibitors)are not tolerated,contraindicated or not affordable for the patient.

Review on the Effect of Glucagon-Like Peptide-1 Receptor Agonists and Dipeptidyl Peptidase-4 Inhibitors for the Treatment of Non-Alcoholic Fatty Liver Disease

Non-alcoholic fatty liver disease（NAFLD） is a common liver disease and it represents the hepatic manifestation of metabolic syndrome, which includes type 2 diabetes mellitus（T2DM）, dyslipidemia, central obesity and hypertension. Glucagon-like peptide-1（GLP-1） analogues and dipeptidyl peptidase-4（DPP-4） inhibitors were widely used to treat T2 DM. These agents improve glycemic control, promote weight loss and improve lipid metabolism. Recent studies have demonstrated that the GLP-1 receptor（GLP-1R） is present and functional in human and rat hepatocytes. In this review, we present data from animal researches and human clinical studies that showed GLP-1 analogues and DPP-4 inhibitors can decrease hepatic triglyceride（TG） content and improve hepatic steatosis, although some effects could be a result of improvements in metabolic parameters. Multiple hepatocyte signal transduction pathways and m RNA from key enzymes in fatty acid metabolism appear to be activated by GLP-1 and its analogues. Thus, the data support the need for more rigorous prospective clinical trials to further investigate the potential of incretin therapies to treat patients with NAFLD.

Dipeptidyl peptidase-4 inhibitor-induced autoimmune diseases:Current evidence

Dipeptidyl peptidase-4 inhibitors(DPP-4i)have an important place in the management of type 2 diabetes.The DPP-4 enzyme is ubiquitously distributed throughout the human body and has multiple substrates through which it regulates several important physiological functions.DPP-4 regulates several immune functions,including T-cell activation,macrophage function,and secretion of cytokines.Studies have reported an increase in autoimmune diseases like bullous pemphigoid,inflammatory bowel disease,and arthritis with DPP-4i use.The relationship of DPP-4i and autoimmune diseases is a complex one and warrants further research into the effect of DPP-4 inhibition on the immune system to understand the pathogenesis more clearly.Whether a particular cluster of autoimmune diseases is associated with DPP-4i use remains an important contentious issue.Nevertheless,a heightened awareness from the clinicians is required to identify and treat any such diseases.Through this review,we explore the clinical and pathophysiological characteristics of this association in light of recent evidence.

Risk of pancreatic adverse events associated with the use of glucagon-like peptide-1 receptor agonist and dipeptidyl peptidase-4 inhibitor drugs: A systematic review and metaanalysis of randomized trials

AIM: To systematically assess risk of pancreatic adverse events with glucagon-like peptide-1(GLP-1) receptor agonist and dipeptidyl peptidase-4(DPP-4) inhibitor drugs.METHODS: We searched Pub Med, Embase, CINAHL, Cochrane review of clinical trials, pharmaceutical company clinical trials register, United States Food and Drug Administration website, European Medicines Agency website and Clinical Trials.gov for randomized controlled trials from inception to October 2013. Randomized control trial studies were selected for inclusion if they reported on pancreatic complication events and/or changes in pancreatic enzyme levels(serum amylase and serum lipase) as adverse events or as serious adverse events for patients who were on GLP-1 receptor agonist and DPP-4 inhibitor drugs. Two independent reviewers extracted data directly. We performed Peto odds ratio(OR) fixed effect meta-analysis of pancreatic adverse events a, and assessed heterogeneity with the I^2 statistic.RESULTS: Sixty-eight randomized controlled trials were eligible. A total of 60720 patients were included in our analysis of the association of risk of pancreatic complication events with GLP-1 agents. A total of 89 pancreatic related adverse events occurred among the GLP-1 agents compared to 74 events among the controls. There was a statistically significant increased risk of elevation of pancreatic enzymes associated with GLP-1 agents compared with control(Peto OR = 3.15, 95%CI: 1.56-6.39, P = 0.001, I2 = 0%). There was no statistically significant difference in the risk of pancreatic adverse event associated with GLP-1 agent compared with controls(Peto OR = 1.00, 95%CI: 0.73-1.37, P = 1.00, I2 = 0%). There were a total of 71 pancreatitis events in patients on GLP-1 agents and 56 pancreatitis events occurred in the control patients. There were 36 reports of pancreatic cancer in these studies. Of these cases, 2 used linagliptin, 2 used alogliptin, 1 used vildagliptin, 7 used saxagliptin while 6 used sitagliptin. The remaining 18 cases occurred among controls.CONCLUSION: Although GLP-1 based agents are associated with pancreatic enzyme elevation, we were unable to confirm a significant risk of pancreatitis or pancreatic cancer.

Neuroprotection by dipeptidyl-peptidase-4 inhibitors and glucagonlike peptide-1 analogs via the modulation of AKT-signaling pathway in Alzheimer’s disease

Alzheimer’s disease(AD)is the most common reason for progressive dementia in the elderly.It has been shown that disorders of the mammalian/mechanistic target of rapamycin(mTOR)signaling pathways are related to the AD.On the other hand,diabetes mellitus(DM)is a risk factor for the cognitive dysfunction.The pathogenesis of the neuronal impairment caused by diabetic hyperglycemia is intricate,which contains neuro-inflammation and/or neurodegeneration and dementia.Glucagon-like peptide-1(GLP1)is interesting as a possible link between metabolism and brain impairment.Modulation of GLP1 activity can influence amyloid-beta peptide aggregation via the phosphoinositide-3 kinase/AKT/mTOR signaling pathway in AD.The GLP1 receptor agonists have been shown to have favorable actions on the brain such as the improvement of neurological deficit.They might also exert a beneficial effect with refining learning and memory on the cognitive impairment induced by diabetes.Recent experimental and clinical evidence indicates that dipeptidyl-peptidase-4(DPP4)inhibitors,being currently used for DM therapy,may also be effective for AD treatment.The DPP-4 inhibitors have demonstrated neuroprotection and cognitive improvements in animal models.Although further studies for mTOR,GLP1,and DPP4 signaling pathways in humans would be intensively required,they seem to be a promising approach for innovative AD-treatments.We would like to review the characteristics of AD pathogenesis,the key roles of mTOR in AD and the preventive and/or therapeutic suggestions of directing the mTOR signaling pathway.

Association between plasma dipeptidyl peptidase-4 levels and cognitive function in perinatal pregnant women with gestational diabetes mellitus

BACKGROUND Dipeptidyl peptidase-4(DPP4)is associated with cognitive dysfunction in patients with type 2 diabetes.AIM To assess a possible relationship between serum DPP4 and cognitive function in perinatal pregnant women with gestational diabetes mellitus(GDM).METHODS The study subjects were divided into three groups:GDM group(n=81),healthy pregnant(HP)group(n=85),and control group(n=51).The Montreal Cognitive Assessment(MoCA)was used to assess the cognitive status of each group.Venous blood samples were collected to measure blood lipids,glycated hemoglobin,and glucose levels.For each participant,a 3-mL blood sample was collected and centrifuged,and the serum was collected.Blood samples were stored at-80℃,and DPP4,interleukin-6(IL-6),and 8-iso-prostaglandin F2α(8-iso-PGF2α),and brain-derived neurotrophic factor(BDNF)were detected using ELISA.RESULTS The MoCA scores in the GDM and HP groups were significantly different from those in the control group in terms of visuospatial/executive function and attention(P<0.05);however,the scores were not significantly different between the GDM and HP groups(P>0.05).In terms of language,the GDM group had significantly different scores from those in the other two groups(P<0.05).In terms of memory,a significant difference was found between the HP and control groups(P<0.05),as well as between the GDM and HP groups.The levels of DPP4,IL-6,and 8-iso-PGF2αin the GDM group were significantly higher than those in the HP and control groups(P<0.05);however,the differences between these levels in the HP and control groups were not significant(P>0.05).The level of BDNF in the GDM group was significantly lower than that in the HP and control groups(P<0.05),although the difference in this level between the HP and control groups was not significant(P>0.05).CONCLUSION Cognitive dysfunction in perinatal pregnant women with GDM mainly manifested as memory loss,which might be associated with elevated DPP4 levels.

Efficacy of omarigliptin,once-weekly dipeptidyl peptidase-4 inhibitor,in patients with type 2 diabetes

BACKGROUND Omarigliptin is one of several once-weekly dipeptidyl peptidase-4 inhibitors(DPP-4is).Despite the high frequency of switching from various daily DPP-4is to omarigliptin in actual clinical practice,data regarding its efficacy in patients with type 2 diabetes(T2D)after switching are limited.AIM To analyze the efficacy of omarigliptin in Japanese patients with T2D who had previously received treatment with other glucose-lowering agents.METHODS Forty-nine T2D patients treated for the first time with omarigliptin were recruited retrospectively and divided into four groups defined as either add-on or switched from daily DPP-4is:switched from linagliptin,switched from sitagliptin,and switched from vildagliptin.During a 3-mo follow-up,the clinical parameters among these groups were assessed and compared,with the impact of the switch on glycemic variability as measured by continuous glucose monitoring also being evaluated in the switched groups.RESULTS Hemoglobin A1c levels saw a significant decrease of-0.32%±0.41%in the add-on group(P=0.002).However,the other groups’variables depended on the preswitch daily DPP-4i:switched from linagliptin,-0.05%±0.22%;switched from sitagliptin,-0.17%±0.33%;and switched from vildagliptin,0.45%±0.42%,which saw significant worsening(P=0.0007).Multivariate logistic regression analysis revealed that switching from vildagliptin to omarigliptin was independently associated with worsening glycemic control(P=0.0013).The mean and standard deviation of sensor glucose value,the mean amplitude of glycemic excursions,and the mean of daily difference significantly improved when switching the patient from either linagliptin or sitagliptin to omarigliptin.However,in patients switched from vildagliptin,not only did the glucose variability indices see no improvements,the mean of daily difference even underwent significant worsening.CONCLUSION Administering omarigliptin as add-on therapy or switching to it from sitagliptin and linagliptin,but not vildagliptin,improves glycemic control and thus should help in decision making when selecting DPP-4is for T2D patients.

MK-0626,a selective DPP-4 inhibitor,attenuates hepatic steatosis in ob/ob mice

AIM: To investigate the mechanism and in vivo effects of MK-0626, a dipeptidyl peptidase-4 inhibitor, on hepatic steatosis using ob/ob mice.

Sodium-dependent glucose transporter 2 inhibitors effects on myocardial function in patients with type 2 diabetes and asymptomatic heart failure

BACKGROUND Sodium-dependent glucose transporter 2 inhibitors(SGLT2i)have shown efficacy in reducing heart failure(HF)burden in a very heterogeneous groups of patients,raising doubts about some contemporary assumptions of their mechanism of action.We previously published a prospective observational study that evaluated mechanisms of action of SGLT2i in patients with type 2 diabetes who were in HF stages A and B on dual hypoglycemic therapy.Two groups of patients were included in the study:the ones receiving SGLT2i as an add-on agent to metformin and the others on dipeptidyl peptidase-4 inhibitors as an add-on to metformin due to suboptimal glycemic control.AIM To evaluate the outcomes regarding natriuretic peptide,oxidative stress,inflammation,blood pressure,heart rate,cardiac function,and body weight.METHODS The study outcomes were examined by dividing each treatment arm into two subgroups according to baseline parameters of global longitudinal strain(GLS),N-terminal pro-brain natriuretic peptide,myeloperoxidase(MPO),high-sensitivity C-reactive protein(hsCRP),and systolic and diastolic blood pressure.To evaluate the possible predictors of observed changes in the SGLT2i arm during follow-up,a rise in stroke volume index,body mass index(BMI)decrease,and lack of heart rate increase,linear regression analysis was performed.RESULTS There was a greater reduction of MPO,hsCRP,GLS,and blood pressure in the groups with higher baseline values of mentioned parameters irrespective of the therapeutic arm after 6 months of follow-up.Significant independent predictors of heart rate decrease were a reduction in early mitral inflow velocity to early diastolic mitral annular velocity at the interventricular septal annulus ratio and BMI,while the predictor of stroke volume index increase was SGLT2i therapy itself.CONCLUSION SGLT2i affect body composition,reduce cardiac load,improve diastolic/systolic function,and attenuate the sympathetic response.Glycemic control contributes to the improvement of heart function,blood pressure control,oxidative stress,and reduction in inflammation.

Renoprotection Provided by Dipeptidyl Peptidase-4 Inhibitors in Combination with Angiotensin Receptor Blockers in Patients with Type 2 Diabetic Nephropathy

Background: Treatment with the dipeptidyl peptidase-4 inhibitors (DPP4i) and angiotensin receptor blockers (ARBs) in patients with type 2 diabetic nephropathy (DN) has not been well characterized. This study aimed to assess the renoprotection of this combined treatment in DN patients.Methods: A total of 159 type 2 DN patients from 2013 to 2015 were enrolled retrospectively from a prospective DN cohort at the National Clinical Research Center of Kidney Diseases, Jinling Hospital (China). Fifty-seven patients received DPP4i and ARB treatment, and 102 patients were treated with ARBs alone. All patients were followed up for at least 12 months. Statistical analyses were performed using Stata version 12.0.Results: There were no significant differences at baseline for age, sex, body mass index, duration of diabetes, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), and estimated glomerular filtration rate (eGFR) between the two groups. Antihypertensive and antidiabetic medication use was similar in each group except calcium channel antagonists (P = 0.032). No significant changes in FBG and HbA1c were observed in the two groups after treatment. The eGFR decreased slower in the DPP4i + ARB group than in the ARB group at 12 months (?12 months: -2.48 ± 13.86 vs. -6.81 ± 12.52 ml·min–1·1.73m–2,P = 0.044). In addition, proteinuria was decreased further in the DPP4i + ARB group than in the ARB group after 24 months of treatment (?24 months: -0.18 [-1.00, 0.17] vs. 0.32 [-0.35, 0.88],P = 0.031). There were 36 patients with an eGFR decrease of more than 30% over 24 months. After adjusting for FBG, HbA1c, and other risk factors, DPP4i + ARB treatment was still associated with a reduced incidence of an eGFR decrease of 20% or 30%.Conclusions: The combined treatment of DPP4i and ARBs is superior to ARBs alone, as evidenced by the greater proteinuria reduction and lower eGFR decline. In addition, the renoprotection of DPP4i combined with ARBs was independent of glycemic control.

DPP-4在脂质代谢及非酒精性脂肪性肝病中的作用研究

二肽基肽酶-4（DPP-4）可能通过灭活胰高血糖素样肽-1、神经肽Y以及调节能量平衡等多种途径影响机体脂质代谢.非酒精性脂肪性肝病（NAFLD）是一种无过量饮酒史,而以肝实质细胞脂肪变性和脂肪贮积为特征的临床综合征,肥胖、高脂血症、胰岛素抵抗在其发生和发展过程中发挥重要作用.DPP-4可能是NAFLD的一种重要调节因子,目前用于2型糖尿病治疗的新型药物DPP-4抑制剂可能在肥胖及NAFLD的控制中发挥重要作用.

Potential roles of glucagon-like peptide-1-based therapies in treating non-alcoholic fatty liver disease

Glucagon-like peptide-1(GLP-1)-based therapies have demonstrated efficacy and safety in treating type 2 diabetes, which shares a similar pathophysiological mechanism with non-alcoholic fatty liver disease(NAFLD). Recent studies showed that glucose-induced GLP-1 secretion was decreased in patients with NAFLD and that the level of dipeptidyl peptidase-4, which inactivates intact GLP-1, was upregulated. Moreover, the expression of the GLP-1 receptor was downregulated in livers from patients with NAFLD, indicating an association of defective GLP-1 signalling with NAFLD. Notably, GLP-1-based therapies are reported to be effective in improving hepatic endpoints in patients with NAFLD, such as reducing hepatic fat content, hepatic steatosis and plasma transaminase levels, and preventing fibrosis. GLP-1-based therapies are beneficial for body weight control and glycaemic normalisation, which are important for the management of NAFLD. Moreover, clinical and preclinical studies showed that GLP-1-based agents might directly exert their actions on the liver through activation of functional GLP-1 receptors in hepatocytes.The possible mechanisms involve regulating gene expression that is associated with insulin resistance and lipid metabolism, and suppressing oxidative stress in the liver cells, thus preventing the development and progression of NAFLD. Based on these promising data, large-scale randomised controlled trials are warranted to assess the efficacy and safety of GLP-1-based therapies in treating NAFLD.

Incretin based therapies:A novel treatment approach for non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease is considered a hepatic manifestation of metabolic syndrome(MS).The current treatment of non-alcoholic fatty liver disease(NAFLD)principally includes amelioration of MS components by lifestyle modifications but the lack of success in their implementation and sustainment arises the need for effective pharmacological agent in fatty liver treatment.Incretins are gut derived hormones secreted into the circulation in response to nutrient ingestion that enhances glucose-stimulated insulin secretion.Glucagon-like peptide-1(GLP-1)is the most important incretin.Its receptor agonist and inhibitors of dipeptidyl peptidase-4(DPP-4)are used in treatment of type2 diabetes mellitus.DPP-4 serum activity and hepatic expression are shown to be elevated in several hepatic diseases.There are several experimental and clinical trials exploring the efficacy of incretin based therapies in NAFLD treatment.They suggest that GLP-1 analogues might have beneficial effect on hepatic steatosis acting as insulin sensitizers and directly by stimulating GLP-1 receptors expressed on hepatocytes.The use of DPP-4 inhibitors also results in hepatic fat reduction but the mechanism of action remains unclear.There is growing evidence that incretin based therapies have beneficial effects on hepatocytes,however further study analysis are needed to assess the long term effect of incretin based therapies on NAFLD.

Crosstalk between gut microbiota and antidiabetic drug action

Type 2 diabetes (T2D) is a disorder characterized by chronic inflated blood glucose levels (hyperglycemia), at first due to insulin resistance and unregulated insulin secretion but with tendency towards global spreading. The gut microbiota is recognized to have an influence on T2D, although surveys have not formed a clear overview to date. Because of the interactions between gut microbiota and host homeostasis, intestinal bacteria are believed to play a large role in various diseases, including metabolic syndrome, obesity and associated disease. In this review, we highlight the animal and human studies which have elucidated the roles of metformin,α-glucosidase inhibitors, glucagon-like peptide-1 agonists, peroxisome proliferator-activated receptors γ agonists, inhibitors of dipeptidyl peptidase-4, sodium/glucose cotransporter inhibitors, and other less studied medications on gut microbiota. This review is dedicated to one of the most widespread diseases, T2D, and the currently used antidiabetic drugs and most promising new findings. In general, the gut microbiota has been shown to have an influence on host metabolism, food consumption, satiety, glucose homoeostasis, and weight gain. Altered intestinal microbiota composition has been noticed in cardiovascular diseases, colon cancer, rheumatoid arthritis, T2D, and obesity. Therefore, the main effect of antidiabetic drugs is on the microbiome composition, basically increasing the short-chain fatty acids-producing bacteria, responsible for losing weight and suppressing inflammation.

Incretin manipulation in diabetes management

Incretin-based therapies have revolutionized the medical management of type 2 diabetes mellitus(T2DM) in the 21 st century. Glucagon-like peptide-1(GLP-1) suppresses appetite and gastric motility, and has trophic effects on pancreas, cardio-protective and renal effects. GLP-1 analogues and dipeptidyl peptidase-4 inhibitors form the incretin-based therapies. Significant reduction of hemoglobin A1 c when used as monotherapy and in combination regimens, favorable effects on body weight, and low risk of hypoglycemia are their unique therapeutic benefits. Their safety and tolerability are comparable to other anti-diabetic medications. Concern about elevated risk of pancreatitis has been discarded by two recent meta-analyses. This article discusses the therapeutic manipulation of incretin system for the management of T2 DM.

Antidiabetic treatment, stroke severity and outcome

Ischemic stroke is a leading cause of mortality and long-term disability worldwide. Given the detrimental effects of acute stroke, several neuroprotective agents have been evaluated in these patients. However, the benefits of the evaluated agents appear to be limited and none is currently recommended for clinical use. On the other hand, prior treatment with agents that are used for the primary and secondary prevention of stroke, including statins and antiplatelets, has been associated with better outcome in patients who experience an acute stroke. In contrast, there are limited data as to whether prior treatment with antidiabetic agents is beneficial in diabetic patients who suffer a stroke. In this context, the findings of a recent study that showed reduced stroke size following pretreatment with linagliptin, a dipeptidyl peptidase-4(DDP-4) inhibitor, compared with glimepiride, in both diabetic and non-diabetic mice, appear promising. Despite these preclinical findings suggesting neuroprotective effects of DPP-4 inhibitors in acute stroke, it is still unclear whether these actions will also be observed in humans. Of note, two recent large randomized, placebo-controlled studies did not show any effect of DPP-4 inhibitors on cardiovascular events, including stroke. Several other ongoing trials are evaluating the effects of DPP-4 inhibitors on cardiovascular morbidity and mortality. These studies also provide a major opportunity to assess whether patients treated with this class of antidiabetic agents will suffer from less severe strokes and whether their outcome after stroke will be more favorable.

Incretin-based therapies in prediabetes: Current evidence and future perspectives

The prevalence of type 2 diabetes(T2D) is evolving globally at an alarming rate. Prediabetes is an intermediate state of glucose metabolism that exists between normal glucose tolerance(NGT) and the clinical entity of T2 D. Relentless β-cell decline and failure is responsible for the progression from NGT to prediabetes and eventually T2 D. The huge burden resulting from the complications of T2 D created the need of therapeutic strategies in an effort to prevent or delay its development. The beneficial effects of incretin-based therapies, dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1(GLP-1) receptor agonists, on β-cell function in patients with T2 D, together with their strictly glucose-depended mechanism of action, suggested their possible use in individuals with prediabetes when greater β-cell mass and function are preserved and the possibility of β-cell salvage is higher. The present paper summarizes the main molecular intracellular mechanisms through which GLP-1 exerts its activity on β-cells. It also explores the current evidence of incretin based therapies when administered in a prediabetic state, both in animal models and in humans. Finally it discusses the safety of incretin-based therapies as well as their possible role in order to delay or prevent T2 D.