Serum interleukin-10 level is increased and correlated positively with disease severity in patients with dipeptidyl peptidase-4 inhibitor-related bullous pemphigoid.

Bullous pemphigoid (BP) is an autoimmune subepidermal blistering disease with a linear deposit of autoantibodies at the epidermal basement membrane zone. It was reported that diabetes patients who took a dipeptidyl peptidase-4 inhibitor (DPP4i), an oral antidiabetic drug, had an increased incidence of BP. However, data on DPP4i-related BP are limited. In our study, we measured serum levels of various cytokines using LEGENDplex and assessed correlations of these serum levels with clinical severity and laboratory data. Serum samples obtained from BP patients who visited our hospital from June 2016 to February 2023 were collected in this study. Patients' background, characteristics, and clinical data were retrospectively collected from their charts. Serum samples from 27 patients with DPP4i-unrelated BP, 17 patients with DPP4i-related BP, and 13 healthy controls were analyzed. Patients with DPP4i-related BP had lower score of Bullous Pemphigoid Disease Area Index (BPDAI)-erythema/urticaria, lower number of circulating eosinophils, and lower titer of anti-BP180 antibody than patients with DPP4i-unrelated BP. The serum interleukin (IL)-6 level was significantly higher in patients with DPP4i-related BP than in healthy controls (P = 0.0037). The serum IL-10 level was significantly higher in patients with DPP4i-related BP than in patients with DPP4i-unrelated BP and in healthy controls (P = 0.0006, P = 0.0448), and was positively correlated with the BPDAI-blister/erosions score (r = 0.757, P = 0.001), BPDAI-erythema/urticaria score (r = 0.616, P = 0.013), and BPDAI-total score (r = 0.833, P < 0.001) in patients with DPP4i-related BP. In conclusion, patients with DPP4i-related BP had increased serum levels of IL-6 and IL-10 compared with healthy controls and positive correlations between the serum IL-10 level and BPDAI scores reflecting clinical severity, indicating that the serum IL-10 level is a potential objective biomarker of disease severity in patients with DPP4i-related BP.

Antidiabetic Treatment and Prevention of Ischemic Stroke: A Systematic Review.

Background: Diabetes mellitus (DM) is a prevalent disease in the general population and also a well-established risk factor for the development of ischemic stroke. Patients who have been diagnosed with diabetes have a 20% higher risk for developing ischemic stroke in comparison to non-diabetic individuals. The aim of the current systematic review is to provide the latest evidence regarding the association between antidiabetic treatment and the prevention of ischemic stroke. Methods: A comprehensive search in scientific literature databases PUBMED, COCHRANE, and SCOPUS was conducted. The studies that were deemed as eligible for this review were those that examined the clinical benefits of therapeutic strategies in terms of preventing ischemic strokes. Results: A total of 32 studies met the established selection criteria. The included studies showed that pioglitazone treatment significantly reduced the risk for recurrent stroke in patients with DM. Furthermore, in the context of primary prevention, the improvement in glycemic control after treatment with the glucagon-like peptide-1 receptor agonists (GLP-1RA) semaglutide and dulaglutide was associated with a reduction in the risk of ischemic stroke in diabetic subjects. Metformin monotherapy may reduce stroke risk, while dipeptidyl peptidase 4 inhibitors, sodium-glucose co-transporter 2 inhibitors, and insulin do not seem to affect the incidence of stroke. Conclusions: The findings of the present systematic review suggest that pioglitazone and GLP-1RA may decrease the risk of stroke. Further studies are needed to provide additional data regarding the preventive effect of novel antidiabetic drugs, such as dual glucose-dependent insulinotropic polypeptide/GLP-1RA agents, on stroke.

An abnormal increase in CD26(-)CD28(-) cytotoxic effector CD4 and CD8 T cell populations in patients with systemic lupus erythematosus.

CD26 is a human T cell costimulatory molecule as well as a T cell subset marker, and increase of CD26+ T cells in inflamed tissues and peripheral blood has been reported in diverse autoimmune diseases. In contrast, our group has previously shown that levels of circulating CD26+ T cells are decreased in patients with systemic lupus erythematosus (SLE), although the role of reduced CD26 T cell surface expression in SLE pathology remains to be elucidated. In the present study, we conducted CD26-based T cell subset analyses utilizing peripheral blood mononuclear cells from 57 SLE patients and 31 healthy adult volunteers. We show that the increase in CD26(-) T cell population reflects the abnormal expansion of CD26(-)CD28(-) cytotoxic subsets of both CD8 T cells and CD4 T cells in SLE patients. Single cell RNA sequencing analysis of the CD26(-)CD28(-) CD4 and CD8 T cell populations reveals unique characteristics with similarities to natural killer T cells. In addition, the level of CD26(-)CD28(-) T cells is increased in some active stage SLE patients with renal manifestation. Meanwhile, effect of prednisolone treatment on these populations varies from patient to patient, with levels of these cytotoxic effector populations still being elevated in some inactive stage SLE patients. Taken together, our data suggest that analysis of these populations in SLE may be a useful tool to classify this markedly heterogeneous condition.

Association between incretin-based drugs and risk of cholangiocarcinoma among patients with type 2 diabetes: A large population-based matched cohort study.

Aim: To examine the association between the use of incretin-based drugs [glucagon-like peptide-1 receptor agonists (GLP-1RAs), dipeptidyl peptidase-4 inhibitors (DPP-4Is)] and the risk of cholangiocarcinoma (CCA) in the United States. Methods: This large population-based, retrospective cohort study using the TriNetX datasets included adult patients with type 2 diabetes mellitus (T2DM) who were new users of GLP-1RAs, DPP-4Is, or other second- or third-line antidiabetic drugs between 2010 and 2021. The primary outcome was the incidence of CCA. Results: A total of 3,816,071 patients were included (mean age, 61.4 years, female, 49.3 %). A 51 % and 23 % risk reduction in CCA after 1 year of exposure to GLP-1RAs (hazard ratio 0.49; 95 % CI 0.40-0.60) and DPP4Is (0.77, 95 % CI 0.67-0.90), respectively compared to new second-or third-line users. Results were consistent at 3, 5, and 7 years of follow-up (0.66, 0.71, and 0.72 for GLP-1RAs and 0.84, 0.87, and 0.85 for DPP-4Is, respectively). Compared to new metformin users, GLP-1RA users were associated with a 42 % lower risk of developing CCA, whereas DPP-4I group was not associated with an increased risk. Conclusions: GLP-1RAs and DPP-4Is were not associated with a significantly increased risk of CCA. GLP-1RAs even showed a reduced risk of CCA development. They can be considered as safe and effective treatment options for patients with T2DM at risk of CCA.

Utilization of Glucagon-Like Peptide-1 Receptor Agonist and Dipeptidyl Peptidase-4 Inhibitors at the Veterans Health Administration.

Background: Glucagon-like peptide-1 receptor agonists (GLP-1RA) and dipeptidyl peptidase-4 inhibitors (DPP-4i) are incretin-based therapies commonly used in the management of type 2 diabetes. Public interest in GLP-1RA soared after discovering their ability to lower body weight in patients without diabetes. Objective: To examine recent trends in usage of GLP-1RA and DPP-4i in the Veterans Health Administration (VHA). Methods: We extracted GLP-1RA and DPP-4i use from the national VHA Corporate Data Workhouse (CDW) between fiscal years (FYs) 2011 to 2021, which encompass medication class, name, dosage, date of filled prescription, and patients' characteristics. Results: A total of 3 037 006 prescriptions for DPP-4i and 2 183 294 prescriptions for GLP-1RA were filled during FY 2011 to 2021. More patients were prescribed DPP-4i (273 002 subjects) compared with GLP-1RA (157 209 subjects) from FY 2011 to 2021. Overall, 10.7% used DPP-4i for 90 days or less in comparison to 9.1% in GLP-1RA (P < 0.001). The proportion of patients prescribed DPP-4i who were 75 years of age or older was relatively stable over the years 2011 to 2021 (mean proportion = 19%). However, the proportion of patients who were 75 years of age or older prescribed GLP-1RA increased from 4.2% in 2011 to 16.9% in 2021. Conclusions: Incretin-based therapies have become a well-established class of drugs within the VHA. Even though DPP-4i usage in older adults has remained stable over the past 10 years, prescriptions for GLP-1RA in older adults have increased multifold over the last few years, which might be attributed to recent trial evidence showing benefit in cardiovascular outcomes and weight reduction.

Hepatoprotective effects of vildagliptin mitigates lung biochemical and histopathological changes in experimental hepatopulmonary syndrome model in rat.

Hepatopulmonary syndrome (HPS) is a liver disease-induced pulmonary complication manifested with arterial hypoxemia. Hepatic cholestasis, encountered in several clinical situations, leads to biliary cirrhosis and HPS, both of which are best reproduced by rat common bile duct ligation (CBDL). Experience from liver transplantation suggests hepatoprotective-based therapy would be most effective in HPS treatment Dipeptidyl peptidase-4 (DPP-4) enzyme is involved in different pathogenic mechanisms of liver diseases. Vildagliptin (Vild) is a DPP-4 inhibitor which possesses favorable anti-inflammatory, anti-oxidant and anti-fibrotic effects. The present work explored hepatoprotective mechanisms of Vild and their participation in its prophylactic effectiveness in HPS induced by CBDL in rats. Male Wistar rats weighing 220-280 g were allocated into 4 groups: normal control, sham, CBDL and CBDL + Vild groups. i.p. saline was administered to the first 3 groups and i.p. Vild (10 mg/kg/day) was given to the fourth group for 6 weeks starting 2 week before CBDL. CBDL produced liver fibrosis, arterial hypoxemia and decreased survivability of rats. It altered liver functions and induced oxidative stress, pro-inflammatory cytokines [tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6)], vasodilatory molecules [endothelin-1 (ET-1), and inducible and endothelial nitric oxide synthases] and angiogenesis-associated protein [vascular endothelial growth factor-A (VEGF-A)] in liver and lung. Vild ameliorated liver fibrosis, and improved hypoxemia and survivability of CBDL rats and reversed these biochemical alterations. Prophylactic Vild administration attenuated CBDL-induced HPS in rats via direct hepatoprotective effects in the form of anti-oxidant, anti-inflammatory, anti-angiogenic and anti-fibrotic effects beside inhibition of pathological intrahepatic vasodilatation.

Comparing Insulin Against Glucagon-Like Peptide-1 Receptor Agonists, Dipeptidyl Peptidase-4 Inhibitors, and Sodium-Glucose Cotransporter 2 Inhibitors on 5-Year Incident Heart Failure Risk for Patients With Type 2 Diabetes Mellitus: Real-World Evidence Study Using Insurance Claims.

Background: Type 2 diabetes mellitus (T2DM) is a common health issue, with heart failure (HF) being a common and lethal long-term complication. Although insulin is widely used for the treatment of T2DM, evidence regarding the efficacy of insulin compared to noninsulin therapies on incident HF risk is missing among randomized controlled trials. Real-world evidence on insulin's effect on long-term HF risk may supplement existing guidelines on the management of T2DM. Objective: This study aimed to compare insulin therapy against other medications on HF risk among patients with T2DM using real-world data extracted from insurance claims. Methods: A retrospective, observational study was conducted based on insurance claims data from a single health care network. The study period was from January 1, 2016, to August 11, 2021. The cohort was defined as patients having a T2DM diagnosis code. The inclusion criteria were patients who had at least 1 record of a glycated hemoglobin laboratory test result; full insurance for at least 1 year (either commercial or Medicare Part D); and received glucose-lowering therapy belonging to 1 of the following groups: insulin, glucagon-like peptide 1 receptor agonists (GLP-1 RAs), dipeptidyl peptidase-4 inhibitors (DPP-4Is), or sodium-glucose cotransporter-2 inhibitors (SGLT2Is). The main outcome was the 5-year incident HF rate. Baseline covariates, including demographic characteristics, comorbidities, and laboratory test results, were adjusted to correct for confounding. Results: After adjusting for a broad list of confounders, patients receiving insulin were found to be associated with an 11.8% (95% CI 11.0%-12.7%), 12.0% (95% CI 11.5%-12.4%), and 15.1% (95% CI 14.3%-16.0%) higher 5-year HF rate compared to those using GLP-1 RAs, DPP-4Is, and SGLT2Is, respectively. Subgroup analysis showed that insulin's effect of a higher HF rate was significant in the subgroup with high HF risk but not significant in the subgroup with low HF risk. Conclusions: This study generated real-world evidence on the association of insulin therapy with a higher 5-year HF rate compared to GLP-1 RAs, DPP-4Is, and SGLT2Is based on insurance claims data. These findings also demonstrated the value of real-world data for comparative effectiveness studies to complement established guidelines. On the other hand, the study shares the common limitations of observational studies. Even though high-dimensional confounders are adjusted, remaining confounding may exist and induce bias in the analysis.

Efficacy of Alogliptin/Metformin Fixed-Dose Combination Tablets and Vildagliptin/Metformin Fixed-Dose Combination Tablets on Glycemic Control in Real-World Clinical Practice for the Patients with Type 2 Diabetes: A Multicenter, Open-Label, Randomized, Parallel Group, Comparative Trial.

Background: This study was aimed to compare the efficacy of two combination tablets of dipeptidyl peptidase-4 (DPP-4) inhibitors and metformin with different dosages, alogliptin/metformin (AM) and vildagliptin/metformin (VM), on glycemic control in patients with type 2 diabetes (T2D). Methods: This was a prospective, multicenter, open-label, randomized, parallel group, comparative trial. After a run-in period of treatment with metformin alone, a total of 59 Japanese outpatients with T2D, aged 20-79 years with glycated hemoglobin (HbA1c) levels of 6.5%-10% were randomly assigned to 12-week AM treatment, alogliptin 25 mg/metformin 500 mg combination tablet orally once a day, or VM treatment, vildagliptin 50 mg/metformin 250 mg combination tablet orally twice a day. The primary endpoints were the changes in HbA1c and fasting plasma glucose (FPG) levels from baseline to week 12 between the two groups. Blinded intermittently scanned continuous glucose monitoring (isCGM) was performed between weeks 10 and 12. The incidence of adverse events during the study was also evaluated. Results: In all, 52 participants were analyzed. Significant decreases in HbA1c and FPG levels from baseline to week 12 were observed in both treatment groups. However, there were no significant differences between the AM and VM groups in the change in HbA1c level (-0.3% and -0.4%, P = 0.309) or the FPG level (-9.0 and -15.0 mg/dL, P = 0.789). The isCGM revealed that both treatments achieved the recommended glycemic target range. No adverse events, such as severe hypoglycemia, were observed in either group. Conclusions: We concluded that there were no significant differences in the efficacy of two combination tablets of DPP-4 inhibitors and metformin with different dosages on glycemic control in patients with T2D.

Long-Term Effects of Incretin-Based Drugs on Glycemic Control in Permanent Neonatal Diabetes.

Permanent neonatal diabetes mellitus (PNDM) is a genetic disorder, characterized by a decrease in endogenous insulin secretion. Therefore, exogenous insulin supplementation plays a central role in controlling glycemia. Although adding a sulfonylurea can help to discontinue insulin, discontinuation is sometimes difficult when the sulfonylurea is administered at older ages. A 24-year-old woman with longstanding PNDM who had poor glycemic control using insulin (47 U/day) and high-dose glibenclamide (0.6 mg/kg/day), had successfully discontinued insulin after initiating the dipeptidyl peptidase-4 inhibitor sitagliptin (50 mg/day). Additionally, hemoglobin A1c levels decreased by 4.8%. Double dosing of sitagliptin and subsequent switching to the glucagon-like peptide-1 receptor agonist semaglutide (0.25 mg/week followed by 0.5 mg/week) further decreased hemoglobin A1c values, with graded improvements in endogenous insulin secretion. There were no episodes of hypoglycemia during which glibenclamide was titrated down from 0.6 to 0.4 mg/kg/day. Intra- and inter-day glucose variability as assessed by continuous glucose monitoring was also improved. In patients with PNDM, administration and dose escalation of incretin-based drugs, in addition to a high-dose sulfonylurea, could be a useful treatment strategy. This strategy may be helpful for discontinuing insulin, downtitrating sulfonylureas, and subsequent achievement of better glycemic control regarding long-term stability and short-term variability.

Empagliflozin Use Is Associated With Lower Risk of All-Cause Mortality, Hospitalization for Heart Failure, and End-Stage Renal Disease Compared to DPP-4i in Nordic Type 2 Diabetes Patients: Results From the EMPRISE (Empagliflozin Comparative Effectiveness and Safety) Study.

Objective: To evaluate the effectiveness of empagliflozin in reducing all-cause mortality (ACM), hospitalization for heart failure (HHF), myocardial infarction (MI), stroke, cardiovascular mortality (CVM), and end-stage renal disease (ESRD) in routine clinical practice in the Nordic countries of the Empagliflozin Comparative Effectiveness and Safety (EMPRISE) study. Methods: This noninterventional, multicountry cohort study used secondary data from four Nordic countries (Denmark, Sweden, Finland, and Norway). Propensity score (PS) matched (1:1) adults with type 2 diabetes (T2D) initiating empagliflozin (a sodium-glucose cotransporter-2 inhibitor) during 2014-2018 who were compared to those initiating a dipeptidyl peptidase-4 inhibitor (DPP-4i). Cox proportional hazards regression modelling was used to assess the risk for ACM, HHF, MI, stroke, CVM, and ESRD. Meta-analyses were conducted and hazard ratios (HRs) with 95% confidence intervals (CIs) from random-effects models were calculated. Results: A total of 43,695 pairs of PS-matched patients were identified. Patients initiating empagliflozin exhibited a 49% significantly lower risk of ACM (HR: 0.51, 95% CI 0.40-0.64) compared to DPP-4i. Additionally, empagliflozin was associated with a 36% significantly lower risk of HHF (HR: 0.64, 95% CI 0.46-0.89), a 52% significantly lower risk of CVM (HR: 0.48, 95% CI 0.37-0.63), and a 66% significantly lower risk of ESRD (HR: 0.34, 95% CI 0.15-0.77) compared to DPP-4i. No significant differences were observed in the risk of stroke and MI between patients initiating empagliflozin compared with those initiating a DPP-4i. Results were generally consistent for subgroups (with/without pre-existing CV disease or congestive heart failure) and in sensitivity analyses. Conclusion: Empagliflozin initiation was associated with a significantly reduced risk of ACM, HHF, CVM, and ESRD compared with initiation of DPP-4i in patients with T2D when examining routine clinical practice data from Nordic countries.

Dipeptidyl peptidase 4 deficiency improves survival after focal cerebral ischemia in mice and ameliorates microglia activation and specific inflammatory markers.

Dipeptidyl peptidase 4 (DPP4; CD26) is involved in the regulation of various metabolic, immunological, and neurobiological processes in healthy individuals. Observations based on epidemiological data indicate that DPP4 inhibition by gliptins, typically used in patients with diabetes, may reduce the risk for cerebral ischemia and may also improve related outcomes. However, as DPP4 inhibitor application is neither complete nor specific for suppression of DPP4 enzymatic activity and DPP4 has non-enzymatic functions as well, the variety of consequences is a matter of debate. Therefore, we here used DPP4 knock-out (KO) mice to analyze the specific contribution of DPP4 to cellular, immunological, and functional consequences of experimental focal cerebral ischemia. We observed a significantly higher survival rate of DPP4 KO mice after ischemia, which was accompanied by a lower abundance of the pro-inflammatory chemokine CCL2 and reduced activation of Iba1-positive microglia cells in brain tissue of DPP4 KO mice. In addition, after ischemia for 24 h to 72 h, decreased concentrations of CCL5 and CCL12 in plasma and of CCL17 in brain tissue of DPP4 KO mice were observed when compared to wild type mice. Other aspects analyzed, such as the functional Menzies score, astrocyte activation and chemokine levels in plasma and brain tissue were affected by ischemia but appeared to be unaffected by the DPP4 KO genotype. Taken together, experimental ablation of DPP4 functions in mice improves survival and ameliorates aspects of cellular and molecular inflammation after focal cerebral ischemia.

The effects of dipeptidyl peptidase-4 inhibitors on cardiac structure and function using cardiac magnetic resonance: a meta-analysis of clinical studies.

Objective: The aim of the study was to evaluate the effect of dipeptidyl peptidase-4 inhibitors (DPP4i) on cardiac structure and function by cardiac magnetic resonance (CMR). Research Methods & Procedures: Database including PubMed, Cochrane library, Embase and SinoMed for clinical studies of DPP4i on cardiac structure and function by CMR were searched. Two authors extracted the data and evaluated study quality independently. Mean difference (MD) or standardized MD and 95% confidence intervals (CI) were used for continuous variables. Review Manager 5.3 was used to performed the analysis. Results: Ten references (nine studies) were included in this meta-analysis. Most of the studies were assessed as well quality by the assessment of methodological quality. For clinical control studies, the merged MD values of △LVEF by fixed-effect model and the pooled effect size in favor of DPP4i was 1.55 (95% CI 0.35 to 2.74, P=0.01). Compared with positive control drugs, DPP4i can significantly improve the LVEF (MD=4.69, 95%CI=2.70 to 6.69), but no such change compared to placebo (MD=-0.20, 95%CI=-1.69 to 1.29). For single-arm studies and partial clinical control studies that reported LVEF values before and after DPP4i treatment, random-effect model was used to combine effect size due to a large heterogeneity (Chi2 = 11.26, P=0.02, I2 = 64%), and the pooled effect size in favor of DPP4i was 2.31 (95% CI 0.01 to 4.62, P=0.05). DPP4i significantly increased the Peak filling rate (PFR) without heterogeneity when the effect sizes of two single-arm studies were combined (MD=31.98, 95% CI 13.69 to 50.27, P=0.0006; heterogeneity test: Chi2 = 0.56, P=0.46, I2 = 0%). Conclusions: In summary, a possible benefit of DPP4i in cardiac function (as measured by CMR) was found, both including ventricular systolic function and diastolic function.

The impact of vildagliptin as an add-on therapy on matrix metalloproteinase-14 levels, liver stiffness and subclinical atherosclerosis in adolescents with type 1 diabetes and non-alcoholic steatohepatitis: A randomized controlled trial.

AIM: Many patients with type 1 diabetes mellitus (T1DM) met the histological criteria for non-alcoholic steatohepatitis (NASH), which leads to cardiovascular disease morbidity and mortality. Matrix metalloproteinase-14 (MMP-14) is involved in cardiovascular disease and atherosclerosis. OBJECTIVES: To assess the impact of oral dipeptidyl peptidase-4 inhibitor, vildagliptin, as adjunctive therapy on NASH in adolescents with T1DM and its effect on glycaemic control, MMP-14 levels and carotid intima media thickness (CIMT). METHODS: Sixty adolescents with T1DM and NASH were randomly assigned to receive oral vildagliptin (50 mg once daily) for 6 months or not. Glycated haemoglobin, lipid profile, hepatic steatosis index, triglyceride glucose (TyG) index and MMP-14 levels were assessed. Transient elastography with controlled attenuation parameter (CAP) was performed together with measuring CIMT. RESULTS: By transient elastography, 12 (20%) patients with T1DM with NASH had elevated liver stiffness ≥7 kPa (F2 stage or higher). Baseline MMP-14 was positively correlated to insulin dose (p = 0.016), triglycerides and TyG index, CIMT, liver stiffness and CAP levels among the studied patients (p < 0.001 for all). After 6 months, patients with T1DM on vildagliptin therapy had significantly lower glycated haemoglobin, lipid profile, hepatic steatosis index and TyG index, as well as MMP-14 (p < 0.001). CIMT, liver stiffness and CAP were significantly decreased post-therapy compared with baseline levels and compared with the control group (p < 0.001). Vildagliptin was safe and well-tolerated. CONCLUSIONS: Administration of vildagliptin for adolescents with T1DM and NASH improved glycaemic control, dyslipidaemia and MMP-14 levels and decreased liver stiffness and CIMT; hence, reducing subclinical atherosclerosis and disease progression.

Effects of dipeptidyl peptidase 4 inhibitors on the risk of acute respiratory failure in patients with type 2 diabetes mellitus: a meta-analysis of cardiovascular outcomes trials.

Dipeptidyl peptidase 4 (DPP-4) inhibitors are new antidiabetic drugs. Their effects on the respiratory system remain unclear. This study aimed to determine the association between DDP-4 inhibitors and acute respiratory failure (ARF) among patients with type 2 diabetes mellitus (T2DM). A meta-analysis was performed by searching the PubMed, Embase, and CENTRAL databases up to July 3rd, 2024, to identify randomized controlled, double-blind, and placebo controlled-cardiovascular outcomes trials (CVOTs) that enrolled participants with T2DM. A total of 6,532 studies were initially retrieved; ultimately, 5 large CVOTs enrolling 47,714 adult T2DM patients were included in the meta-analysis. Overall, there were a nonsignificant increase in the risk of ARF in the DDP-4 inhibitor group compared with the placebo group (RR, 1.72; 95% CI, 0.59 to 4.97; p = 0.319). This is the first meta-analysis to evaluate the association between DDP-4 inhibitors and ARF among T2DM patients. In general, these findings suggest that DPP-4 inhibitors may slightly, but non-significantly, increase the risk of ARF in T2DM patients. As few studies are available and few ARF events occurred, further well-designed large-scale studies need to be performed.

A Systematic Approach to Evaluating Instrumental Variable Assumptions: Applied Example of Glucose-lowering Medications and Risk for Hospitalized Heart Failure in Older Adults.

One obstacle to adopting instrumental variable (IV) methods in pharmacoepidemiology is their reliance on strong, unverifiable assumptions. We can falsify IV assumptions by leveraging the causal structure, which can strengthen or refute their plausibility and increase the validity of effect estimates. We illustrate a systematic approach to evaluate calendar time IV assumptions in estimating the known effect of thiazolidinediones on hospitalized heart failure. Using cohort entry time before and after 09/2010, when the U.S. Food and Drug Administration issued a safety communication as a proposed IV, we estimated IV and propensity score-weighted 2-year risk differences (RDs) using Medicare data (2008-2014). We (i) performed inequality tests, (ii) identified the negative control IV/outcome using causal assumptions, (iii) estimated RDs after narrowing the calendar time range and excluding patients likely associated with unmeasured confounding, (iv) derived bounds for RDs, and (v) estimated the proportion of compliers and their characteristics. The findings revealed that IV assumptions were violated and RDs were extreme, but the assumptions became more plausible upon narrowing the calendar time range and restricting the cohort by excluding prevalent heart failure (the strongest measured predictor of outcome). Systematically evaluating IV assumptions could help detect bias in IV estimators and increase their validity.

Dipeptidyl peptidase 4: A predictor of ferroptosis in ulcerative colitis.

BACKGROUND: With its rapidly increasing incidence and prevalence, ulcerative colitis (UC) has become a major global health challenge. Recent evidence suggests that ferroptosis plays a significant role in the development of UC. However, the relationship between ferroptosis and the progression of UC needs to be extensively studied. METHODS: The differentially expressed genes in UC patients were screened from the GEO database. The ferroptosis-related genes were obtained from FErrDB and GeneCards. The UC subtypes were identified with the R package "CancerSubtype" and evaluated with consensus clustering (CC) to identify gene expression patterns in patients with UC. The key genes were detected with qRT-PCR, Western blot, and immunohistochemistry in vitro and in vivo models. Ferroptosis was identified with western blotting on ferrotic-associated proteins and staining on Fe2+ with commercial FerroOrange kits. RESULTS: Dipeptidyl peptidase 4 (DPP4), also known as CD26, is a potential biomarker for ferroptosis in UC patients. Transcriptome sequencing data showed a positive correlation between decreased DPP4 expression and proinflammatory cytokines such as TNF-α, IL-6, and IL-ß, as well as immune cell infiltration in the colon tissues of UC patients. Furthermore, DPP4 was strongly associated with ferroptosis biomarkers, particularly in Subtype 2 of UC. Interestingly, our study also found that DPP4 expression was significantly reduced in RSL3-treated ferroptotic intestinal epithelial cells, more so than in LPS-treated cell models. Inhibition of DPP4 had a significant impact on the expression of ferroptotic biomarkers. Additionally, DPP4 expression was decreased in the colon tissues of DSS-treated mice, and the ferroptosis inhibitor Ferritin-1 effectively counteracted the effects of DSS on immune cell infiltration, colon length, and DPP4 expression. CONCLUSIONS: DPP4 can serve as a biomarker for ferroptosis in the diagnosis and management of UC.

Dipeptidyl peptidase-4 marks distinct subtypes of human adipose stromal/stem cells with different hepatocyte differentiation and immunoregulatory properties.

BACKGROUND: Human adipose-derived stromal/stem cells (hASCs) play important roles in regenerative medicine and numerous inflammatory diseases. However, their cellular heterogeneity limits the effectiveness of treatment. Understanding the distinct subtypes of hASCs and their phenotypic implications will enable the selection of appropriate subpopulations for targeted approaches in regenerative medicine or inflammatory diseases. METHODS: hASC subtypes expressing dipeptidyl peptidase-4 (DPP4) were identified via fluorescence-activated cell sorting (FACS) analysis. DPP4 expression was knocked down in DPP4+ hASCs via DPP4 siRNA. The capacity for proliferation, hepatocyte differentiation, inflammatory factor secretion and T-cell functionality regulation of hASCs from DPP4-, DPP4+, and control siRNA-treated DPP4+ hASCs and DPP4 siRNA-treated DPP4+ hASCs were assessed. RESULTS: DPP4+ hASCs and control siRNA-treated DPP4+ hASCs presented a lower proliferative capacity but greater hepatocyte differentiation capacity than DPP4- hASCs and DPP4 siRNA-treated DPP4+ hASCs. Both DPP4+ hASCs and DPP4- hASCs secreted high levels of vascular endothelial growth factor-A (VEGF-A), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6), whereas the levels of other factors, including matrix metalloproteinase (MMP)-1, eotaxin-3, fractalkine (FKN, CX3CL1), growth-related oncogene-alpha (GRO-alpha, CXCL1), monokine induced by interferon-gamma (MIG), macrophage inflammatory protein (MIP)-1beta, and macrophage colony-stimulating factor (M-CSF), were significantly greater in the supernatants of DPP4+ hASCs than in those of DPP4- hASCs. Exposure to hASC subtypes and their conditioned media triggered changes in the secreted cytokine profiles of T cells from healthy donors. The percentage of functional T cells that secreted factors such as MIP-1beta and IL-8 increased when these cells were cocultured with DPP4+ hASCs. The percentage of polyfunctional CD8+ T cells that secreted multiple factors, such as IL-17A, tumour necrosis factor alpha (TNF-α) and TNF-ß, decreased when these cells were cocultured with supernatants derived from DPP4+ hASCs. CONCLUSIONS: DPP4 may regulate proliferation, hepatocyte differentiation, inflammatory cytokine secretion and T-cell functionality of hASCs. These data provide a key foundation for understanding the important role of hASC subpopulations in the regulation of T cells, which may be helpful for future immune activation studies and allow them to be customized for clinical application.

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 anti-inflammatory (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.

Cofrogliptin once every 2 weeks as add-on therapy to metformin versus daily linagliptin in patients with type 2 diabetes in China: A randomized, double-blind, non-inferiority trial.

AIM: We evaluated the efficacy and safety of cofrogliptin, a novel dipeptidyl peptidase-4 inhibitor taken once every 2 weeks (Q2W), compared with linagliptin (taken daily) in patients with type 2 diabetes inadequately controlled on metformin in China. MATERIALS AND METHODS: In this phase 3 randomized, double-blind, active-controlled, multicentre study, patients were randomly assigned 1:1:1 to receive cofrogliptin 10 mg Q2W, cofrogliptin 25 mg Q2W, or linagliptin 5 mg daily, all as an add-on treatment to metformin, for 24 weeks. Eligible patients could enter an open-label extension period and receive cofrogliptin 25 mg Q2W for an additional 28 weeks. The primary endpoint was change in glycated haemoglobin from baseline to 24 weeks, with a non-inferiority margin of 0.4% for cofrogliptin versus linagliptin treatment. RESULTS: Overall, 465 patients entered the 24-week treatment period (median age: 57.0 years). The least-squares mean (standard error) change in glycated haemoglobin from baseline to week 24 was -0.96 (0.063), -0.99 (0.064) and -1.07 (0.065) for the cofrogliptin 10 mg, cofrogliptin 25 mg and linagliptin 5 mg groups, respectively. The between-group difference met the predefined margin for non-inferiority of cofrogliptin (10 and 25 mg) versus linagliptin treatment. The incidence of common adverse events (≥5% patients) during the 24-week treatment period was similar between treatment groups. There were no serious hypoglycaemic events. CONCLUSION: In Chinese patients with type 2 diabetes inadequately controlled on metformin, the glucose-lowering effect of cofrogliptin (Q2W) was non-inferior to linagliptin (daily), with a similar safety profile maintained over 52 weeks of treatment.