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Epidemiological studies report an elevated risk of Parkinson's disease (PD) in patients with type 2 diabetes mellitus (T2DM) that is mitigated in those prescribed dipeptidyl peptidase 4 (DPP-4) inhibitors. With an objective to characterize clinically translatable doses of DPP-4 inhibitors (gliptins) in a well-characterized PD rodent model, sitagliptin, PF-00734,200 or vehicle were orally administered to rats initiated either 7-days before or 7-days after unilateral medial forebrain bundle 6-hydroxydopamine (6-OHDA) lesioning. Measures of dopaminergic cell viability, dopamine content, neuroinflammation and neurogenesis were evaluated thereafter in ipsi- and contralateral brain. Plasma and brain incretin and DPP-4 activity levels were quantified. Furthermore, brain incretin receptor levels were age-dependently evaluated in rodents, in 6-OHDA challenged animals and human subjects with/without PD. Cellular studies evaluated neurotrophic/neuroprotective actions of combined incretin administration. Pre-treatment with oral sitagliptin or PF-00734,200 reduced methamphetamine (meth)-induced rotation post-lesioning and dopaminergic degeneration in lesioned substantia nigra pars compacta (SNc) and striatum. Direct intracerebroventricular gliptin administration lacked neuroprotective actions, indicating that systemic incretin-mediated mechanisms underpin gliptin-induced favorable brain effects. Post-treatment with a threefold higher oral gliptin dose, likewise, mitigated meth-induced rotation, dopaminergic neurodegeneration and neuroinflammation, and augmented neurogenesis. These gliptin-induced actions associated with 70-80% plasma and 20-30% brain DPP-4 inhibition, and elevated plasma and brain incretin levels. Brain incretin receptor protein levels were age-dependently maintained in rodents, preserved in rats challenged with 6-OHDA, and in humans with PD. Combined GLP-1 and GIP receptor activation in neuronal cultures resulted in neurotrophic/neuroprotective actions superior to single agonists alone. In conclusion, these studies support further evaluation of the repurposing of clinically approved gliptins as a treatment strategy for PD., (© 2024. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

The role of the gut microbiota and its interplay with host metabolic health, particularly in the context of type 2 diabetes mellitus (T2DM) management, is garnering increasing attention. Dipeptidyl peptidase 4 (DPP4) inhibitors, commonly known as gliptins, constitute a class of drugs extensively used in T2DM treatment. However, their potential interactions with gut microbiota remain poorly understood. In this study, we employed computational methodologies to investigate the binding affinities of various gliptins to DPP4-like homologs produced by intestinal bacteria. The 3D structures of DPP4 homologs from gut microbiota species, including Segatella copri , Phocaeicola vulgatus , Bacteroides uniformis , Parabacteroides merdae , and Alistipes sp., were predicted using computational modeling techniques. Subsequently, molecular dynamics simulations were conducted for 200 ns to ensure the stability of the predicted structures. Stable structures were then utilized to predict the binding interactions with known gliptins through molecular docking algorithms. Our results revealed binding similarities of gliptins toward bacterial DPP4 homologs compared to human DPP4. Specifically, certain gliptins exhibited similar binding scores to bacterial DPP4 homologs as they did with human DPP4, suggesting a potential interaction of these drugs with gut microbiota. These findings could help in understanding the interplay between gliptins and gut microbiota DPP4 homologs, considering the intricate relationship between the host metabolism and microbial communities in the gut.

Dipeptidyl peptidase-4 (DPP4) inhibitors are a potent therapeutic treatment for type 2 diabetes mellitus (T2DM). There is a family of compounds used as DPP4 inhibitors (DPP4Is) called gliptins. They bind tightly to DPP4 to form an inactive protein-ligand complex. However, there remains a need to identify novel DPP4Is that are more efficacious and safer due to the increasing prevalence of T2DM and the undesirable side effects of gliptins. To identify potential DPP4Is, we screened over 1800 novel compounds in a comparative study with gliptins. We performed dual-factor molecular docking to assess the binding affinity of the compounds to DPP4 and found four compounds with a higher binding affinity to DPP4 than currently used gliptins. The newly identified compounds interacted with the dyad glutamate (GLU205 and GLU206) and tyrosine (TYR662 and TYR666) residues in DPP4's active site. We performed molecular dynamics simulations to determine the stability of the protein-ligand complexes formed by the compounds and DPP4. Furthermore, we examined the toxicity and pharmacological profile of the compounds. The compounds are drug-like, easy to synthesize, and relatively less toxic than gliptins. Collectively, our results suggest that the novel compounds are potential DPP4Is and should be considered for further studies to develop novel antidiabetics.Communicated by Ramaswamy H. Sarma.

Aim: To assess and compare the metabolic and vascular effectiveness of sodium-glucose cotransporter 2 inhibitors (SGLT-2i) and dipeptidyl peptidase-4 inhibitors (DPP-4i) in the clinical practice of patients with type 2 diabetes in Italy., Materials and Methods: GIOIA is a 2-year prospective, multicentre, quasi-experimental study that enrolled patients with type 2 diabetes initiating SGLT-2i or DPP-4i for inadequate glycaemic control [glycated haemoglobin (HbA1c) >7%] between March 2018 and March 2021. The primary endpoints were changes in markers of organ damage [carotid intima-media thickness (CIMT), albuminuria, myocardial function] and HbA1c from baseline to year 2., Results: In total, 1150 patients were enrolled in the study (SGLT-2i n = 580, DPP-4i n = 570). Patients initiated on SGLT-2i were younger (about 6 years) and heavier (about 11 kg), had higher HbA1c level (1% more), more albuminuria and cardiovascular events (16% more) than patients initiated on DPP-4i. CIMT and echocardiographic parameters were not significantly different. Propensity score matching yielded two groups, each consisting of 155 patients with diabetes with similar baseline characteristics. Despite a significant similar reduction in HbA1c levels in both groups (-0.8%), more patients on SGLT-2i had regression of CIMT and albuminuria (22% and 10%, respectively, p < .001 vs. DPP-4i); more patients on DPP-4i had progression of CIMT and albuminuria (23% and 28%, respectively, p < .001 vs. SGLT-2i). Left ventricular ejection fraction improved slightly (3%, p = .043) on SGLT-2i only., Conclusions: In a real-world setting, both SGLT-2i and DPP-4i improve glycaemic control persisting after 2 years of treatment, with a robust effect on both CIMT and albuminuria regression for SGLT-2i as compared with DPP-4i in the propensity score matching., (© 2024 John Wiley & Sons Ltd.)

Aims: Dipeptidyl peptidase 4 (DPP4) has been proposed as a coreceptor for SARS-CoV-2 cellular entry. Considering that type 2 diabetes mellitus (T2DM) has been identified as the most important risk factor for SARS-CoV-2, and that gliptins (DPP4 inhibitors) are a prescribed diabetic treatment, this study aims to unravel the impact of DPP4 in the intersection of T2DM/COVID-19., Materials and Methods: We analyzed 189 serum human samples, divided into six clinical groups (controls, T2DM, T2DM + gliptins, COVID-19, COVID-19 + T2DM, and COVID-19 + T2DM + gliptins), measuring DPP4 protein concentration and activity by Western blot, ELISA, and commercial activity kits. The obtained results were verified in Huh-7 cellular models., Key Findings: Both DPP4 concentration and activity were decreased in COVID-19 patients, and as in T2DM patients, compared to controls. Despite these lower levels, the ratio of DPP4 activity/concentration in COVID-19 sera was the highest (0.782 ± 0.289 μU/ng vs. 0.547 ± 0.050 μU/ng in controls, p < 0.0001), suggesting a compensating mechanism in these patients. Supernatants of Huh-7 cells incubated with COVID-19 serum showed a consistent and significantly lower DPP4 concentration and activity. Furthermore, COVID-19 + T2DM + gliptins patients showed a higher serum DPP4 concentration and activity than T2DM + gliptin subjects (p < 0.05), indicating that sera from COVID-19 convalescents interfere with gliptins., Significance: Either SARS-CoV-2 or some metabolites present in the sera of COVID-19-convalescent patients interact with soluble DPP4 or even gliptins themselves since the inhibitory effect of gliptins on DPP4 activity is being prevented. The interactions between DPP4, gliptins, and SARS-CoV-2 should be further elucidated to reveal the mechanism of action for these interesting observations., Competing Interests: Declaration of competing interest The authors declare that they have no competing interests., (Copyright © 2023. Published by Elsevier Inc.)

Dipeptidyl peptidase-4 (DPP-4), also known as CD26, is a 110-kDa cell surface glycoprotein with enzymatic and signal transducing activity. DPP-4/CD26 is expressed by various cells, including CD4+ and CD8+ T cells, B cells, dendritic cells, macrophages, and NK cells. DPP-4 inhibitors (DPP-4i) were introduced to clinics in 2006 as new oral antihyperglycemic drugs approved for type 2 diabetes mellitus treatment. In addition to glucose-lowering effects, emerging data, from clinical studies and their animal models, suggest that DPP-4i could display anti-inflammatory and immunomodulatory effects as well, but the molecular and immunological mechanisms of these actions are insufficiently investigated. This review focuses on the modulatory activity of DPP-4i in the immune system and the possible application of DPP-4i in other immune-related diseases in patients with or without diabetes., (© 2023 Wiley-VCH GmbH.)

Bullous pemphigoid (BP), the most common autoimmune blistering disease, is characterized by the presence of autoantibodies targeting BP180 and BP230 in the basement membrane zone. This leads to the activation of complement-dependent and independent pathways, resulting in proteolytic cleavage at the dermoepidermal junction and an eosinophilic inflammatory response. While numerous drugs have been associated with BP in the literature, causality and pathogenic mechanisms remain elusive in most cases. Dipeptidyl peptidase 4 inhibitors (DPP4i), in particular, are the most frequently reported drugs related to BP and, therefore, have been extensively investigated. They can potentially trigger BP through the impaired proteolytic degradation of BP180, combined with immune dysregulation. DPP4i-associated BP can be categorized into true drug-induced BP and drug-triggered BP, with the latter resembling classic BP. Antineoplastic immunotherapy is increasingly associated with BP, with both B and T cells involved. Other drugs, including biologics, diuretics and cardiovascular and neuropsychiatric agents, present weaker evidence and poorly understood pathogenic mechanisms. Further research is needed due to the growing incidence of BP and the increasing identification of new potential triggers.

Cluster of differentiation 26 (CD26)/dipeptidyl peptidase 4 (DPP4) is an exopeptidase that is expressed as a transmembrane protein in many organs but also present in a circulating soluble form. Beyond its enzymatic and costimulatory activity, CD26/DPP4 is involved in the pathogenesis of chronic fibrotic diseases across many organ types, such as liver cirrhosis, kidney fibrosis and lung fibrosis. Organ fibrosis is associated with a high morbidity and mortality, and there are no causative therapies that can effectively attenuate the progress of the disease. Growing evidence suggests that inhibiting CD26/DPP4 can modulate the profibrotic tissue microenvironment and thus reduce fibrotic changes within affected organs. This review summarizes the role of CD26/DPP4 in fibroproliferative disorders and highlights new opportunities for an antifibrotic treatment by CD26/DPP4 inhibition. As a major advantage, CD26/DPP4 inhibitors have been in safe and routine clinical use in type 2 diabetes for many years and thus qualify for repurposing to repurpose as a promising therapeutic against fibrosis. LINKED ARTICLES: This article is part of a themed issue on Translational Advances in Fibrosis as a Therapeutic Target. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v180.22/issuetoc., (© 2022 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

Dipeptidyl peptidase 4 (DPP4) is a serine protease known to cleave incretin hormones, which stimulate insulin secretion after food intake, a fact that supported the development of its inhibitors (DPP4i or gliptins) for the treatment of type 2 diabetes mellitus. In addition to their glucose-lowering effects, DPP4i show benefits for the cardiovascular system that could be related, at least in part, to their protective action on vascular endothelium. DPP4i have been associated with the reversal of endothelial dysfunction, an important predictor of cardiovascular events and a hallmark of diseases such as atherosclerosis, diabetes mellitus, hypertension, and heart failure. In animal models of these diseases, DPP4i increase nitric oxide bioavailability and limits oxidative stress, thereby improving the endothelium-dependent relaxation. Similar effects on flow-mediated dilation and attenuation of endothelial dysfunction have also been noted in human studies, suggesting a value for gliptins in the clinical scenario, despite the variability of the results regarding the DPP4i used, treatment duration, and presence of comorbidities. In this mini-review, we discuss the advances in our comprehension of the DPP4i effects on endothelial regulation of vascular tone. Understanding the role of DPP4 and its involvement in the signaling mechanisms leading to endothelial dysfunction will pave the way for a broader use of DPP4i in conditions that endothelial dysfunction is a pivotal pathophysiological player.

Dipeptidyl peptidase 4 (DPP4) inhibitors are a class of antidiabetic medications that cause glucose-dependent increase in incretins in diabetic patients. One of the two incretins, glucagon-like peptide-1 (GLP-1), beside its insulinotropic activity, has been studied for extra pancreatic effects. Most of DPP4 inhibitors (DPP4i) have been investigated in in vivo and in vitro models of diabetic and nondiabetic cardiovascular diseases including heart failure, hypertension, myocardial ischemia or infarction, atherosclerosis, and stroke. Results of preclinical studies proved prominent therapeutic potential of DPP4i in cardiovascular diseases, regardless the presence of diabetes. This review aims to present an updated summary of the cardiovascular protective and therapeutic effects of DPP4 inhibitors through the past 5 years focusing on the molecular mechanisms beneath these effects. Additionally, based on the results summary presented here, future studies may be conducted to elucidate or illustrate some of these findings which can add clinical benefits towards management of diabetic cardiovascular complications., (© 2022. The Author(s).)

Gestational diabetes mellitus (GDM) is a metabolic disease affecting an increasing number of pregnant women around the world. It is not only associated with numerous perinatal complications but also has long-term consequences impacting maternal health and fetal development. To prevent them, it is important to keep glucose levels under control. As much as 15-30% of GDM patients will require treatment with insulin, metformin, or glyburide. With that in mind, it is crucial to keep searching for novel and improved pharmacotherapies. Nowadays, there are ongoing studies investigating the use of other groups of drugs that have proven successful in the treatment of T2DM. Glucagon-like peptide-1 (GLP-1) receptor agonist and dipeptidyl peptidase-4 (DPP-4) inhibitor are among the drugs targeting the incretin system and are currently receiving significant attention. The aim of our review is to demonstrate the potential of these medications in treating GDM and preventing its later complications. It seems that both groups may be successful in the GDM management used alone or as an addition to better-known drugs, including metformin and glyburide. However, more clinical trials are needed to confirm their importance in GDM treatment and to demonstrate effective therapeutic strategies.

The use of dipeptidyl peptidase 4 (DPP4) inhibitors, (also known as gliptins), is associated with an increased risk of bullous pemphigoid (BP), an autoimmune blistering skin disease. To explore the mechanism behind gliptin-associated BP we investigated circulating autoantibodies against the major BP autoantigen BP180 in serum samples from patients with type 2 diabetes (T2D) with preceding gliptin medication (n = 136) or without (n = 136). Sitagliptin was the most frequently prescribed gliptin (125/136 patients). Using an ELISA assay, we showed that IgG autoantibodies against the immunodominant NC16A domain of BP180 were found in 5.9% of gliptin treated and in 6.6% of non-gliptin treated T2D patients. We found that 28% of gliptin treated patients had IgG autoantibodies recognizing the native full-length BP180 in ELISA, but among non-gliptin treated the seropositivity was even higher, at 32%. Further ELISA analysis of additional serum samples (n = 57) found no major changes in the seropositivity against BP180 during a follow-up period of about nine years. In immunoblotting, full-length BP180 was recognized by 71% of gliptin treated and 89% of non-gliptin treated T2D patients, but only by 46% of the age-and sex-matched controls. The chemokine stromal derived factor-1(SDF-1/CXCL12) is one of the major substrates of DPP4. Immunostainings showed that the expression of SDF-1 was markedly increased in the skin of BP patients, but not affected by prior gliptin treatment. We found that the use of gliptins decreased the serum level of SDF-1α in both BP and T2D patients. Our results indicate that the autoantibodies against the linear full-length BP180 are common in patients with T2D, but seropositivity is unaffected by the use of sitagliptin., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Nätynki, Leisti, Tuusa, Varpuluoma, Huilaja, Izumi, Herukka, Ukkola, Junttila, Kokkonen and Tasanen.)

Bullous pemphigoid (BP) is the most common autoimmune bullous skin disease that affects primarily patients older than 60 years. The majority of BP cases are spontaneous, but BP can also be triggered by certain drugs' exposures. Since 2011, a growing number of observations has been reporting cases of BP in Type 2 diabetic patients. These forms have been linked to the use of a new category of anti-diabetic drugs called dipeptidyl peptidase inhibitors (DPP-4i) or gliptins, but to date, the exact pathophysiological mechanisms underlying this association are not completely elucidated. Although conventional and gliptin-associated BP are thought to share similar clinical and histopathological features, our thorough review of the most recent literature, shows that these 2 forms are quite distinct: DPP-4-i-associated BP seems to appear at an earlier age than spontaneous BP, it may manifest either as a noninflammatory or inflammatory phenotype, while the conventional form presents with a typical inflammatory phenotype. Additionally, an important distinctive histological feature was recently shown in Gliptin-associated BP: these forms may present a less significant eosinophils infiltrate in the upper dermis of peri-blister lesions compared to the skin of patients with spontaneous BP, and this seems a specific feature of the clinically non-inflammatory forms. In accordance with previous literature, we found that the direct immunofluorescence (DIF) gives identical findings in both DPP-4i-associated and conventional forms of BP which is an IgG and complement C3 deposition as a linear band at the dermal-epidermal junction in perilesional skin. Indirect immunofluorescence shows the presence of IgG circulating autoantibodies in the patient's serum which titer does not differ between spontaneous and DPP-4i-associated BP, while the specificity of these autoantibodies, may be different in spontaneous, induced non-inflammatory and induced inflammatory forms, epitope spreading phenomenon seems to play a role in determining these specificities. Further research, based on integrated epidemiological, clinical, histo-immunological and pharmacogenomic approaches, may give more insight into these forms of BP. This combined approach will allow to better define BP endotypes and to unveil the mechanism of spontaneous or drug-induced breakage of the immunotolerance to skin self-antigens., (© 2021. The Author(s).)

Background: Bullous pemphigoid is the most common bullous chronic autoimmune skin disease. Recent studies have suggested dipeptidyl-peptidase 4 inhibitors as possible predisposing agents of bullous pemphigoid. The objective of our study was to prospectively estimate the association between gliptins and the development of bullous pemphigoid., Methods: We conducted a prospective study which included all patients diagnosed with biopsy-proven bullous pemphigoid in the Dermatology Department of our hospital between April 1, 2009 and December 31,2019. The diagnosis of bullous pemphigoid was based on specific clinical, histological and immunological features., Results: Overall 113 consecutive patients (age 75 ± 13 years, 62 females) with the diagnosis of bullous pemphigoid were enrolled. Seventy-six patients (67.3%) suffered from type 2 Diabetes and 52 (46%) were treated with dipeptidyl-peptidase 4 inhibitors. The most frequent prescribed gliptin was vildagliptin, being administered to 45 cases (39.8% of total patients enrolled, 86.5% of the patients treated with gliptins). Gliptins were withdrawn immediately after the diagnosis of bullous pemphigoid, which together with steroid administration led to remission of the rash., Conclusions: This study revealed that treatment with dipeptidyl-peptidase 4 inhibitors, especially vildagliptin, is significantly associated with an increased risk of bullous pemphigoid development.

A novel coronavirus disease, COVID-19, has emerged as a global public health issue. Clinical course of disease significantly correlates with the occurrence of some comorbidities, among them type 2 diabetes. According to recent structural studies the dipeptidyl peptidase 4, a key molecule in the pathophysiology of diabetes, may influence the course of COVID-19. Since DPP4 inhibitors, gliptins, are widely used in diabetes patients, the exact role of DPP4 modulation in SARS-CoV-2 infection, at least in that group, urgently needs to be clarified. In this short review, we discuss this issue with more detail.

Aims: Medication adherence and persistence are important determinants of treatment success in type 2 diabetes mellitus (T2DM). This systematic review and meta-analysis evaluated the real-world adherence, persistence, and in-class switching among patients with T2DM prescribed dipeptidyl peptidase-4 (DPP4) inhibitors., Methods: MEDLINE, EMBASE, Cochrane Library, PsychINFO, and CINAHL were searched for relevant observational studies published in the English language up to 20 December 2019. This was supplemented by manual screening of the references of included papers. Random-effects meta-analysis was performed., Results: Thirty-four cohort studies involving 594,138 patients with T2DM prescribed DPP4 inhibitors from ten countries were included. The pooled proportion adherent (proportion of days covered (PDC) or medication possession ratio (MPR) ≥ 0.80) was 56.9% (95% confidence interval [CI] 49.3-64.4) at one year and 44.2% (95% CI 36.4-52.1) at two years. The proportion persistent with treatment decreased from 75.6% (95% CI 71.5-79.5) at six months to 52.8% (95% CI 51.6-59.8) at two years. No significant differences in adherence and persistence were observed between individual DPP4 inhibitors. At one year, just 3.2% (95% CI 3.1-3.3) of patients switched from one DPP4 inhibitor to another. Switching from saxagliptin and alogliptin to others was commonest., Conclusions: Adherence to and persistence with DPP4 inhibitors is suboptimal but similar across all medications within the class. While in-class switching is uncommon, saxagliptin and alogliptin are the DPP4 inhibitors most commonly switched. Interventions to improve treatment adherence and persistence among patients with T2DM prescribed DPP4 inhibitors may be warranted.

Dipeptidyl peptidase-4 (DPP-4) inhibitors or gliptins belong to the class of incretin mimetics. These drugs have been available on the market for the management of type 2 diabetes mellitus (T2DM) for over a decade. Sitagliptin, linagliptin, vildagliptin, saxagliptin and alogliptin are widely available globally, whilst anagliptin, gemigliptin and teneliptin are used mainly in the Asian countries. The glycemic control conferred by DPP-4 inhibitors varies among individual molecules with an average reduction of glycated hemoglobin (HbA1c) ranging between -0.5 to -1.0% with monotherapy. Additive effects on HbA1c reduction may result from combination therapy with other antidiabetics. Weak evidence from various studies suggests that DPP-4 inhibitors may be useful in treating nonalcoholic fatty liver disease (NAFLD) and polycystic ovary syndrome (PCOS). DPP-4 inhibitors safety is not established in pregnancy, and there is only meagre evidence of its use in T2DM among children. In line with the United States Food and Drug Administration (US FDA) recommendations, sitagliptin, linagliptin, saxagliptin and alogliptin have undergone rigorous cardiovascular outcome trials (CVOTs) in recent years, and the safety data for vildagliptin is available through retrospective analysis of various studies in meta-analysis. Small clinical trial, and meta-analysis based data are available for the CV safety of other DPP-4 inhibitors. In general, the CVOTs and other safety data do not reveal serious warning signals except for saxagliptin (higher risk of hospitalization from heart failure [hHF]), although there is no robust data on the risk of hHF among patients with moderate to severe HF at baseline treated with other DPP-4 inhibitors. This review critically appraises the efficacy and cardiovascular safety of DPP-4 inhibitors to empower clinicians to use this class of antidiabetic medications judiciously., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Aim: We examined associations of eight SNPs in/near seven candidate genes with glycemic response to 6 month treatment with DPP4 inhibitors. Patients & methods: 206 patients with type 2 diabetes (116 men and 90 women) were treated with sitagliptin or vildagliptin (both 100 mg/day) in combination with metformin or metformin/sulphonylurea over 6 months, and the reduction in glycated hemoglobin (HbA 1c ) was measured. Results: Rs6923761 in GLP1R was significantly associated with a reduction in HbA 1c (adjusted p = 0.006). Homozygotes for the minor A allele had smaller reduction in HbA 1c by 0.4% (4 mmol/mol) than the G allele carriers (p = 0.016). Conclusion: The missense variant rs6923761 in the  GLP1R gene was associated with a smaller glycemic response to 6 month gliptin therapy in diabetic patients of central European origin.

Background Bullous pemphigoid has been associated to dipeptidase-4 inhibitors. Objectives Addressing the potential Bullous pemphigoid-dipeptidase-4 inhibitors association based on pharmacovigilance data currently available in Spain in order to obtain a composite disproportionality estimator from all the data generated by the case-non case studies conducted to this date. Setting The Spanish Pharmacovigilance System for Human Use Drugs database. Method Case-non case study based on the Spanish Pharmacovigilance System for Human Use Drugs notifications submitted between 2007 and 2018 (n = 169,280), using the Medical Dictionary for Regulatory Activities term (Preferred Term) 'pemphigoid' for sitagliptin, vildagliptin, saxagliptin, linagliptin, and alogliptin (n = 1952). As negative control, we used acetaminophen, while furosemide was the positive control. A pooled reported odds ratio analysis in the French, Japanese, and Spanish national pharmacovigilance databases was performed. On The Spanish Pharmacovigilance System for Human Use Drugs, we conducted a bullous pemphigoid-metformin association analysis within the period 1982-2018. Main outcome measure Adverse reaction cases in pharmacovigilance databases and the disproportionality through the reporting odds ratio. Results Within The Spanish Pharmacovigilance System for Human Use Drugs, we found 45 cases of bullous pemphigoid in dipeptidase-4 inhibitors patients. Median age was 77 years (range 72-82). The median latency period was 7 months (range 0.23-86). The Bullous pemphigoid-dipeptidase-4 inhibitors association was established with a reporting odd ratio = 70.0 (95% confidence intervals 49.1-10.1). In the combined analysis of the three aforementioned pharmacovigilance databases, the pooled reporting odd ratio was 81.0 (95% confidence intervals 69.5-94.4). Conclusion The composite estimator for the three national pharmacovigilance databases yields clear evidence of a Bullous pemphigoid-dipeptidase-4 inhibitors association, which was statistically significant for both the pharmacological class as a whole and each of the dipeptidase-4 inhibitors agents under investigation. Metformin's role in the incidence of bullous pemphigoid appeared casual rather than causal. No differences between Caucasian and Asian populations were noted.

Background: The association between dipeptidyl peptidase 4 inhibitors (DPP-4i) and bullous pemphigoid (BP) has been demonstrated in several studies. The main aim of this study was to estimate the use of DPP-4i treatment in patients diagnosed with BP in our setting., Methods: We selected patients histologically diagnosed with BP in our department between October 2015 and October 2018 and performed a retrospective chart review to assess clinical and epidemiological data and direct immunofluorescence (DIF) patterns., Results: Of the 70 patients diagnosed with BP during the study period, 50% were diabetic and 88.57% of these were being treated with a DPP-4i when diagnosed with BP. The most common DPP-4i was linagliptin (used in 18.6% of patients), followed by vildagliptin (17.1%). The median latency period between initiation of DPP-4i treatment and diagnosis of BP was 27.5 months for all treatments, 16 months for linagliptin, and 39 months for vildagliptin (log rank < 0.01). A negative DIF result was significantly more common in patients not being treated with a DPP-4i. The DIF pattern most strongly (and significantly) associated with DPP-4i treatment was linear immunoglobulin G deposits along the dermal-epidermal junction. DPP-4i treatment was withdrawn in 87% of patients and 96% of these achieved a complete response., Conclusions: DPP-4i treatment is very common in patients with BP in our setting. The latency period between start of treatment and onset of BP seems to be shorter with linagliptin than with other types of gliptins. Patients receiving DPP-4i treatment may show different DIF patterns to those not receiving treatment., (Copyright © 2019 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.)

Cardiovascular complications are main cause of increased mortality in patients with type 2 diabetes. Decrease of overall cardiovascular risk and subsequently cardiovascular morbidity and mortality in type 2 diabetes patients is therefore an important treatment aim. To this end, intensive intervention of classical risk factors such as dyslipidemia, arterial hypertension, smoking along with lifestyle intervention is necessary. Good diabetes control optimally with the use of antidiabetic medication and smoking with positive effect on cardiovascular complication is of high importance as well. Incretin-based therapy includes an approach based on an increase of endogenous GLP-1 concentrations by inhibition of its breakdown by dipeptidyl-peptidase 4 (DPP-4 inhibitors or gliptins) or he use of GLP-1 receptor agonists that owing to modified structure have much longer half-life than endogenous GLP-1 and act the use through stimulation of GLP-1 receptor. The aim of this paper is to summarize the use of these two groups of antidiabetic drugs - gliptins and GLP-1 receptor agonists - in patients with type 2 diabetes focusing on the their cardiovascular effects and their influence on cardiovascular complications.

Background: Kidney transplant recipients may develop post-transplant diabetes mellitus (PTDM). Dipeptidyl peptidase 4(DPP-4) inhibitors are evolving agents in the management of patients with diabetes mellitus., Aim: To evaluate the efficacy and safety of DPP-4 inhibitors in the management of post-transplant diabetes mellitus (PTDM) in renal transplant recipients., Methods: We performed a systematic search of the electronic databases using keys words and Mesh terms. Data were extracted and reviewed using structured proforma. A comprehensive review of the eligible studies was performed independently by each of two reviewers; conflicts were resolved by the third reviewer. The primary efficacy endpoint was the difference in glycosylated hemoglobin (HbA1c) comparing any of the DPP-4 inhibitors to either placebo or other hypoglycaemic agent. The primary safety endpoints were the worsening of graft functions and change in Tacrolimus trough level. We performed the Random effect model using standardised mean difference., Results: We identified seven studies that were eligible for the systematic review; only one study compared Sitagliptin to insulin Glargine. One study involved head to head comparison of three DPP-4 inhibitors. The other five studies were pooled in the meta-analysis. DPP-4 inhibitors had a favourable glycemic effect as measured by HbA1c when compared to either placebo or oral anti-hyperglycemic medications (standardised mean difference in HbA1c = -0.993, 95% CI= -1.303 to -0.683, P=0.001). DPP-4 inhibitors use did not result in significant change in eGFR ((standardised mean difference = 0.147, 95% CI= -0.139 - 0.433, p=0.312).) nor Tacrolimus level (standardised Mean Difference= 0.152, 95% CI= -0.172 to 0.477, P=0.354)., Conclusion: Current evidence supports the short term efficacy and safety of DDP-4 inhibitor agents in the management of post transplantation diabetes mellitus (PTDM) in kidney transplant recipients. However, more RCTs are required to investigate the long-term safety and efficacy of these agents in kidney transplant recipients., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Bullous pemphigoid (BP) is an organ-specific autoantibody-mediated blistering skin disease that mainly affects the elderly. Typical clinical features include the widespread blisters, often preceded by and/or associated with itchy urticarial or eczema-like lesions. BP patients have circulating autoantibodies against BP180 and/or the plakin family protein BP230 both of which are components of hemidesmosomes in basal keratinocytes. Most BP autoantibodies particularly target the epitopes within the non-collagenous NC16A domain of BP180. Clinical findings and murine models of BP have provided evidence of a pathogenic role of anti-NC16A autoantibodies. However, it is largely unknown what triggers the breakage of immunotolerance against BP180 in elderly individuals. The incidence of BP has been increased over the past two decades in several countries. Aside from aging populations, the factors behind this phenomenon are still not fully understood. Neurodegenerative diseases such as multiple sclerosis, Parkinson's disease, and certain dementias are independent risk factors for BP. Recently several case reports have described BP in patients with diabetes mellitus (DM) patients who have been treated with dipeptidyl peptidase-4 inhibitors (DPP-4i or gliptins), which are a widely used class of anti-DM drugs. The association between the use of DPP-4is, particularly vildagliptin, and BP risk has been confirmed by several epidemiological studies. Evidence suggests that cases of gliptin-associated BP in Japan display certain features that set them apart from cases of "regular" BP. These include a "non-inflammatory" phenotype, targeting by antibodies of different immunodominant BP180 epitopes, and a specific association with the human leukocyte antigen (HLA) types. However, recent studies in European populations have found no major differences between the clinical and immunological characteristics of gliptin-associated BP and "regular" BP. The DPP-4 protein (also known as CD26) is ubiquitously expressed and has multiple functions in various cell types. The different effects of the inhibition of DPP-4/CD26 activity include, for example, tissue modeling and regulation of inflammatory cells such as T lymphocytes. Although the pathomechanism of gliptin-associated BP is currently largely unknown, investigation of the unique effect of gliptins in the induction of BP may provide a novel route to better understanding of how immunotolerance against BP180 breaks down in BP.

Background: Dipeptidyl Peptidase 4 (DPP 4) enzyme cleaves an incretin-based glucoregulatory hormone Glucagon Like Peptide -1 from N-terminal where penultimate amino acid is either alanine or proline. Several DPP 4 inhibitors, "gliptins", are approved for the management of Type 2 Diabetes or are under clinical trial. In the present study, combined pharmacophore and docking-based virtual screening protocol were used for the identification of new hits from the Specs Database, which would inhibit DPP 4., Methods: The entire computational studies were performed using the Discovery Studio v. 4.1 software package, Pipeline Pilot v. 9.2 (Accelrys Inc.) and FRED v. 2.2.5 (OpenEye Scientific Software). Common feature pharmacophore model was generated from known DPP 4 inhibitors and validated by Receiver Operating curve analysis and GH-scoring method. Database search of Specs commercial database was performed using validated pharmacophore. Hits obtained from pharmacophore search were further docked into the binding site of DPP 4. Based on the analysis of docked poses of hits, 10 compounds were selected for in- vitro DPP 4 enzyme inhibition assay., Results: Based on docking studies, virtual hits were predicted to form interaction with essential amino acid residues of DPP 4 and have an almost similar binding orientation as that of the reference molecule. Three compounds having Specs database ID- AN-465/42837213, AP-064/42049348 and AN- 465/43369427 were found to inhibit DPP 4 enzyme moderately., Conclusion: The present study demonstrates a successful utilization of in-silico tools in the identification of new DPP 4 inhibitor, which can serve as a starting point for the development of novel DPP 4 inhibitors., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.net.)

Objective: To describe the safety profile of linagliptin., Methodology: Systematic review using PubMed/MEDLINE, BVS and Web of Science. The search strategy "Linagliptin" AND "safety" was used. The inclusion criteria were clinical trials with a control group composed of conventional DM2 pharmacotherapy., Results: We identified 16 studies, and the most frequent adverse events (AEs) were nasopharyngitis with linagliptin at 5 and 10mg in monotherapy (31.6% and 29.6%, respectively) and gastrointestinal events (>10.0%) with linagliptin in combination. Of the AEs, 14.9 (±3.1)% were associated with the use of linagliptin in monotherapy, and 17.6 (±6.0)% in combination. The linagliptin AEs have a varied occurrence and frequency, ranging from mild to moderate intensity., (Copyright © 2018 Primary Care Diabetes Europe. Published by Elsevier Ltd. All rights reserved.)

This study compared dipeptidyl peptidase-4 (DPP-4) inhibitory activity of citrus bioflavonoid nutraceuticals compared with three gliptins. Citrus bioflavonoid standards and three commercially available citrus bioflavonoid supplements (Thompson's Super Bioflavonoid Complex ® (SB), Ethical Nutrients Bioflavonoids Plus Vitamin C ® (EN), and Country Life Citrus Bioflavonoids and Rutin ® (CB)) were considered in this study. Ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis was undertaken to identify and quantitate the citrus bioflavonoids present in each supplement. The DPP-4 inhibitory activity was determined by fluorometric assay. All of the tested individual citrus flavonoids demonstrated DPP-4 inhibitory activity, with IC 50 values ranging from 485 μM (rutin) to 5700 μM (hesperitin and eriodictyol). Similarly, the flavonoid supplements had IC 50 values of 16.9 mg/mL (EN), 3.44 mg/mL (SB) and 2.72 mg/mL (CB). These values compare with gliptin IC 50 values of 0.684 μM (sitagliptin), 0.707 μM (saxagliptin) and 2.286 μM (vildagliptin). The supplement flavonoid content varied from 11.98% (CB) to 5.26% (EN) and 14.51% (SB) of tablet mass, corresponding to daily flavonoid doses of around 300, 150 and 400 mg, respectively, with CB and SB containing rutin at levels of 7.0% and 7.5% of tablet mass, respectively. While our data demonstrated that citrus bioflavonoid based supplements do possess DPP-4 inhibitory activity, they are several orders of magnitude less potent than gliptins. Further studies using higher concentrations of citrus bioflavonoids, as well as investigations into antioxidant properties which may add additional benefit are warranted., (Copyright © 2018 Elsevier Inc. All rights reserved.)

The inhibition of dipeptidyl peptidase-IV (DPP-IV) has emerged over the last decade as one of the most effective treatments for type 2 diabetes mellitus, and consequently (a) 11 DPP-IV inhibitors have been on the market since 2006 (three in 2015), and (b) 74 noncovalent complexes involving human DPP-IV and drug-like inhibitors are available at the Protein Data Bank (PDB). The present review aims to (a) explain the most important activity cliffs for DPP-IV noncovalent inhibition according to the binding site structure of DPP-IV, (b) explain the most important selectivity cliffs for DPP-IV noncovalent inhibition in comparison with other related enzymes (i.e., DPP8 and DPP9), and (c) use the information deriving from this activity/selectivity cliff analysis to suggest how virtual screening protocols might be improved to favor the early identification of potent and selective DPP-IV inhibitors in molecular databases (because they have not succeeded in identifying selective DPP-IV inhibitors with IC 50 ≤ 100 nM). All these goals are achieved with the help of available homology models for DPP8 and DPP9 and an analysis of the structure-activity studies used to develop the noncovalent inhibitors that form part of some of the complexes with human DPP-IV available at the PDB., (© 2018 Wiley Periodicals, Inc.)

Background: Dipeptidyl peptidase-4 (DPP-4) inhibitors (gliptins) are approved drugs for the treatment of hyperglycemia in patients with type 2 diabetes. These effects are mainly mediated by inhibiting endogenous glucagon-like peptide-1 (GLP-1) cleavage. Interestingly, gliptins can also improve stroke outcome in rodents independently from GLP1. However, the underlying mechanisms are unknown. Stromal cell-derived factor-1α (SDF-1α) is a DPP-4 substrate and CXCR4 agonist promoting beneficial effects in injured brains. However, SDF-1α involvement in gliptin-mediated neuroprotection after ischemic injury is unproven. We aimed to determine whether the gliptin linagliptin improves stroke outcome via the SDF-1α/CXCR4 pathway, and identify additional effectors behind the efficacy., Methods: Mice were subjected to stroke by transient middle cerebral artery occlusion (MCAO). linagliptin was administered for 3 days or 3 weeks from stroke onset. The CXCR4-antagonist AMD3100 was administered 1 day before MCAO until 3 days thereafter. Stroke outcome was assessed by measuring upper-limb function, infarct volume and neuronal survival. The plasma and brain levels of active GLP-1, GIP and SDF-1α were quantified by ELISA. To identify additional gliptin-mediated molecular effectors, brain samples were analyzed by mass spectrometry., Results: Linagliptin specifically increased active SDF-1α but not glucose-dependent insulinotropic peptide (GIP) or GLP-1 brain levels. Blocking of SDF-1α/CXCR4 pathway abolished the positive effects of linagliptin on upper-limb function and histological outcome after stroke. Moreover, linagliptin treatment after stroke decreased the presence of peptides derived from neurogranin and from an isoform of the myelin basic protein., Conclusions: We showed that linagliptin improves functional stroke outcome in a SDF-1α/CXCR4-dependent manner. Considering that Calpain activity and intracellular Ca 2+ regulate neurogranin and myelin basic protein detection, our data suggest a gliptin-mediated neuroprotective mechanism via the SDF-1α/CXCR4 pathway that could involve the regulation of Ca 2+ homeostasis and the reduction of Calpain activity. These results provide new insights into restorative gliptin-mediated effects against stroke.

Introduction: Angioedema is a potentially fatal adverse drug reaction of some medications, as swellings of the upper airways can cause death by asphyxiation. Angiotensin converting enzymeinhibitors are widely known to cause angioedema but less is known about the association between dipeptidyl peptidase-4 inhibitors (gliptins) and angioedema. Dipeptidyl peptidase-4 inhibitors are antidiabetic drugs used to improve glycaemic control. They, as a class effect, inadvertently affect the degradation of the vasoactive kinins bradykinin and substance P, both of which can cause angioedema due to vasodilatation and increase in vascular permeability in the capillaries., Objective: To assess the risk and pathomechanism of angioedema due to inhibition of dipeptidyl peptidase- 4 inhibitors when used as monotherapy and in combination with angiotensin converting enzymeinhibitors., Method: PubMed, Embase, the Cochrane Library, PubMed Central, Web of Science, Google Scholar and clinicaltrials.gov were searched using different combinations of keywords "angioedema", "dipeptidyl peptidase 4", "dipeptidyl peptidase 4 inhibitors", "gliptins", "bradykinin", "substance P" and "angiotensin converting enzyme-inhibitors". Original research papers were preferably used as references and their bibliographies were used to further the search for original research results., Results: Both angiotensin converting enzyme and dipeptidyl peptidase-4 are major enzymes in the degradation pathway of bradykinin and substance P, and when inhibited pharmacologically - especially at the same time - the theoretical risk of angioedema is increased due to accumulation of vasoactive kinins., Conclusion: Treatment with dipeptidyl peptidase-4 inhibitors must be carefully considered and monitored especially during concurrent treatment with angiotensin converting enzyme-inhibitors or when treating patients with a known predisposition to angioedema., (Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.)

Purpose: To compare time to a composite endpoint of non-fatal acute myocardial infarction, non-fatal stroke or all-cause mortality in patients with type 2 diabetes mellitus who had their treatment intensified with a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy (metformin plus sulfonylurea) failure., Methods: A retrospective cohort study was conducted on 5238 patients newly treated with either a dipeptidylpeptidase-4 inhibitor or insulin following dual-therapy failure (2007-2014). Data were sourced from UK General Practices. The risk of the composite outcome was compared between two treatment groups: metformin + sulfonylurea + insulin ( n = 1584) and metformin + sulfonylurea + dipeptidylpeptidase-4 inhibitor ( n = 3654), while adjusting for baseline covariates. Follow-up was for up to 5 years. Propensity score matching analysis and Cox proportional hazard models were employed., Results: Overall, 123 and 171 composite outcome events occurred among patients who added insulin versus dipeptidylpeptidase-4 inhibitor, respectively (44.5 vs 14.6 events per 1000 person-years). Addition of insulin was associated with a significantly higher hazard ratio versus the addition of a dipeptidylpeptidase-4 inhibitor (adjusted hazard ratio = 2.6, 95% confidence interval: 1.9-3.4; p < 0.01), an effect that was more pronounced in obese (body mass index: 30-34.9 kg/m 2 ) patients (corresponding adjusted hazard ratio 3.6, 95% confidence interval: 2.3-5.6; p < 0.01)., Conclusion: In routine clinical practice, intensification of metformin + sulfonylurea therapy by adding insulin is associated with increased risk of cardiovascular events and death compared with adding a dipeptidylpeptidase-4 inhibitor. These findings are in line with suggestions from previous studies regarding the cardiovascular safety of insulin in type 2 diabetes mellitus, but should be interpreted with caution.

Bullous pemfigoid (BP), an autoimmune disorder, can also be induced by some medications. Vildagliptin is a new drug used to treat diabetes mellitus (DM). Recently, a few cases of vildagliptin-induced BP have been described in the literature. We report a patient with BP in which vildagliptin was thought to be as a possible causative agent. The awareness of BP development risk during gliptin therapy can prevent unnecessary usage of systemic drugs with serious side effects.

Background: Patients with type 2 diabetes present with an accelerated atherosclerotic process. Animal evidence indicates that dipeptidyl peptidase-4 inhibitors (gliptins) have anti-inflammatory and anti-atherosclerotic effects, yet clinical data are scarcely available., Design and Methods: A prospective, randomized, open-label study was performed in 60 patients with coronary artery disease (CAD) and type 2 diabetes, who participated in a cardiac rehabilitation program. After a washout period of 3 weeks, patients were randomized in a 2:1 ratio to receive combined vildagliptin/metformin therapy (intervention group: n = 40) vs. metformin alone (control group: n = 20) for a total of 12 weeks. Blinded assessment of interleukin-1ß (IL-1ß, the primary endpoint), hemoglobin A1c (HbA1c), and high sensitivity C reactive protein (hsCRP), were performed at baseline and after 12 weeks., Results: Mean age of study patients was 67 ± 9 years, 75% were males, and baseline HbA1c and inflammatory markers levels were similar between the two groups. At 12 weeks of follow up, levels of IL-1ß, hsCRP, and HbA1c were significantly lower in the intervention group as compared with the control group. There was a continuous elevation of IL-1ß among the control group, which was not observed in the intervention group (49 vs. 4%, respectively; p < 0.001). The hsCRP was lowered by 60% in the vildagliptin/metformin group vs. 23% in the metformin group (p < 0.01). Moreover, a significant relative reduction of the HbA1c was seen in the intervention group (7% reduction, p < 0.03)., Conclusion: The addition of vildagliptin to metformin treatment in patients with type 2 diabetes and CAD led to a significant suppression of the IL-1ß elevation during follow up. A significant relative reduction of hsCRP and HbA1c in the intervention group was also observed. Trial registration NCT01604213.

Background: Type 2 diabetes mellitus (T2DM) is associated with an increased risk of stroke and an unfavourable outcome following stroke. Apart from pioglitazone, glucose-lowering modalities have not been shown to protect against stroke. Nevertheless, there is evidence from experimental studies of potential neuroprotective effects with dipeptidyl peptidase (DPP)-4 inhibitors, especially if treatment starts before stroke., Objective: To perform a meta-analysis of available evidence regarding the risk of stroke in individuals taking DPP-4 inhibitors., Methods: All available data from prospective randomized placebo-controlled trials involving DPP-4 inhibitors in T2DM patients published up to December 2015 were considered. The included trials reported data on the incidence of stroke with a recruitment rate of at least 100 diabetes patients and a follow-up of at least 12 weeks., Results: A total of 19 small randomized clinical trials (RCTs) evaluating the efficacy and safety of gliptins (n=9278), along with three multicentre prospective double-blind placebo-controlled RCTs assessing cardiovascular outcomes as the primary endpoint and involving 36,395 T2DM patients, were included in the analysis. Pooled analysis of the small RCTs showed a non-significant trend towards benefit with DPP-4 inhibitors against stroke [odds ratio (OR): 0.639, 95% confidence interval (CI): 0.336-1.212; P=0.170]. In contrast, in the analysis of RCTs reporting on cardiovascular safety, there was no difference in the risk of stroke with gliptin treatment compared with a placebo (OR: 0.996, 95% CI: 0.850-1.166; P=0.958)., Conclusion: The promising data from experimental studies regarding cardioprotective gliptin-associated effects against stroke were not supported by available data from trials specifically looking at cardiovascular safety., (Copyright © 2016 Elsevier Masson SAS. All rights reserved.)

The pace of anti-diabetic drug discovery is very slow in spite of increasing rate of prevalence of Type 2 Diabetes which remains a major public health concern. Though extensive research steps are taken in the past decade, yet craves for better new treatment strategies to overcome the current scenario. One such general finding is the evolution of gliptins which discriminately inhibits DPP4 (Dipeptidyl peptidase-4) enzyme. Although the mechanism of action of gliptin is highly target oriented and accurate, still its long-term use stands unknown. This step calls for a fast, flexible, and cost-effective strategies to meet the demands of producing arrays of high-content lead compounds with improved efficiency for better clinical success. The present review highlights the available gliptins in the market and also other naturally occurring DPP4 enzyme inhibitors. Along with describing the known inhibitors and their origin in this review, we attempted to identify a probable new lead compounds using advanced computational techniques. In this context, computational methods that integrate the knowledge of proteins and drug responses were utilized in prioritizing targets and designing drugs towards clinical trials with better efficacy. The compounds obtained as a result of virtual screening were compared with the commercially available gliptin in the market to have better efficiency in the identification and validation of the potential DPP4 inhibitors. The combinatorial computational methods used in the present study identified Compound 1: 25022354 as promising inhibitor., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Aim: To assess intraindividually the effects of DPP-IV inhibition on the subpopulations of immune cells in type 2 diabetes mellitus (DM2) patients during the course of treatment with sitagliptin., Methods: In this open label non-randomized observational study with a control group DM2 patients were examined before the initiation of the DPP-IV inhibitor administration (sitagliptin 100mg once daily) and then after 4weeks and 12months. Inhibition of the blood plasma DPP-IV enzymatic activity was determined by a chromogenic assay, the immunophenotyping of the blood cell subpopulations was performed using flow cytometry and blood plasma cytokine concentrations were quantified using an array-based multiplex ELISA. All parameters were evaluated in relation to the entry values in individual patients., Results: The blood plasma DPP-IV enzymatic activity was effectively inhibited during the sitagliptin treatment. A significant decrease of the proportion of Treg cells (to 86±31% (median±SD) of entry values, p=0.001) and an increase of Th1 cells (to 120±103% (median±SD) of entry values, p=0.004) were observed after 4weeks but not after one year of the sitagliptin treatment. No changes were observed in the ratio of CD4(+)/CD8(+) cells, in the quantity of NK and Th2 cells and blood plasma cytokine levels., Conclusions: Sitagliptin treatment may cause temporary changes of the proportion of lymphocyte subpopulations in patients with DM2. The consequent deregulation of the immune system should be considered as a possible cause of the eventual side effects of long term DPP-IV inhibition., (Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.)

Gliptins are accepted as a standard therapy for diabetes mellitus today. By inhibition of the enzyme dipeptidyl peptidase 4 (DPP4), gliptins prolong the GLP1-dependent insulin secretion in the pancreatic β-cells and thus support physiological blood glucose control. Various studies have now raised hope for an additional protective effect of pharmacological DPP4 inhibition in vascular diseases. Besides GLP1, especially, the inhibition of SDF1 cleavage has been shown to depict a relevant mechanism to enhance endothelial regeneration and reduce atherosclerosis progression via the SDF1-CXCR4 axis. Furthermore, several clinical trials have now shown an excellent safety profile of gliptin therapy in cardiovascular risk patients. In this review, we give a comprehensive overview on DPP4-dependent vascular functions and pathophysiological mechanisms with a detailed discussion of the underlying molecular mechanisms. We further analyse the role of pharmacological DPP4 inhibitors and their potential therapeutic impact on endothelial function and regeneration besides their effect during atherosclerosis development. Finally, we discuss presently available data from in vitro and in vivo studies with respect to the results of the recent clinical trials in diabetic and non-diabetic patients., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)

Streptococcus mutans harbours an intracellular, human DPP IV-analogous enzyme Xaa-Pro dipeptidyl-peptidase (EC 3.4.14.11). According to previous reports, an extracellular isozyme in S. gordonii and S. suis has been associated with virulence. Speculating that even an intracellular form may aid in virulence of S. mutans, we have tried to purify, characterize and evaluate enzyme inhibition by specific inhibitors. The native enzyme was partially purified by ion-exchange and gel filtration chromatography. Owing to low yield, the enzyme was overexpressed in Lactococcus lactis and purified by affinity chromatography. The recombinant enzyme (rSm-XPDAP) had a specific activity of 1070 U mg(-1), while the Vmax and Km were 7 μM min(-1) and 89 ± 7 μM (n = 3), respectively. The serine protease inhibitor phenylmethylsulphonyl fluoride and a DPP IV-specific inhibitor diprotin A proved to be active against rSm-XPDAP. As a novel approach, the evaluation of the effect of anti-human DPP IV (AHD) drugs on rSm-XPDAP activity found saxagliptin to be effective to some extent (Ki = 129 ± 16 μM), which may lead to the synthesis and development of a new class of antimicrobial agents., (© FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Gliptins are anti-type 2 diabetes (T2D) drugs that regulate glycaemia by preventing endogenous glucagon-like peptide-1 (GLP-1) degradation. Chronically administered gliptins before experimental stroke can also induce neuroprotection, and this effect is potentially relevant for reducing brain damage in patients with T2D and high risk of stroke. It is not known, however, whether acute gliptin treatment after stroke (mimicking a post-hospitalization treatment) is neuroprotective or whether gliptin-mediated neuroprotection occurs via GLP-1-receptor (GLP-1R) activation. To answer these two questions, wild-type and glp-1r(-/-) mice were subjected to transient middle cerebral artery occlusion (MCAO). Linagliptin was administered acutely (50 mg/kg intravenously), at MCAO time or chronically (10 mg/kg orally) for 4 weeks before and 3 weeks after MCAO. Neuroprotection was assessed by stroke volume measurement and quantification of NeuN-positive surviving neurons. Plasma/brain GLP-1 levels and dipeptidyl peptidase-4 activity were also measured. The results show that the linagliptin-mediated neuroprotection against stroke requires chronic pretreatment and does not occur via GLP-1R. The findings provide essential new knowledge with regard to the potential clinical use of gliptins against stroke, as well as a strong impetus to identify gliptin-mediated neuroprotective mechanisms., (© 2016 John Wiley & Sons Ltd.)

Previous studies have offered weak and conflicting evidence regarding the impact of incretin-based oral antihyperglycemic agents on risk of acute pancreatitis. This meta-analysis of three recent mega-trials found an 82% increase in the odds of acute pancreatitis with the use of these agents compared to usual care (95% CI, 1.17-2.82)., (Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.)

Aims: Dipeptidyl peptidase-4 inhibitors (DPP 4i) are oral hypoglycemic agents and are supposed to be beneficial in the early stages of diabetes. In this study, we evaluated the role of DPP4i in long standing type 2 diabetes mellitus (T2DM)., Materials and Methods: This retrospective data analysis was conducted from the patient records. All the patients (T2DM>5 years; Age>50 years; Gliptin use >12 months) were divided into 2 groups based on the duration of T2DM: Group A (<10 years) and Group B (>10 years). We excluded patients with type 1 diabetes and drug default of more than one month. Our primary objective was to study the change in HbA1c and secondary objectives were change in body weight and insulin requirement. Data are presented as mean ± S.D and comparison between the groups was done using Mann-Whitney and Fisher's exact tests., Results: The study participants (n=501) had a mean age (64.2 ± 8.2 yr), diabetes duration (10.1 ± 4.9 yr), body weight (65.3 ± 9.5 kg), BMI (23.4 ± 3.9 kg/m(2)) and HbA1c of 9.7 ± 1.3%. The use of gliptins resulted in similar HbA1c reduction between the groups (p=0.8405) and greater reduction of insulin requirement in group B (p=0.0433) at the end of one year. Body weight and hypoglycemia episodes did not differ between the groups., Conclusion: DPP4 inhibitors give similar benefit irrespective of the duration of diabetes and our data gives reassurance about their role in long standing diabetes., (Copyright © 2014 Diabetes India. Published by Elsevier Ltd. All rights reserved.)

The dipeptidyl peptidase-IV (DPP-IV) inhibitors, also known as gliptins, are widely used in clinical practice either as monotherapy or in combination with other agents for the management of type 2 diabetes mellitus (T2DM). The gliptins are effective, safe, well tolerated, and conveniently administered once/day. Moreover, these agents have a low risk for drug interactions and do not require initial dosage titrations to lessen adverse effects. They are not only clinically desirable, having the most favorable side-effect profile of all available antihyperglycemic medications, but they can also be used in any stage of renal or hepatic impairment. The antihyperglycemic effects of gliptins are attributed to inhibition of the DPP-IV enzyme, thereby prolonging the half-life (t1/2 ) of incretin hormones (substrates) to promote glucose-stimulated insulin secretion. Beyond their glucose-lowering effects, gliptins may also reduce the risk of cardiovascular disease by improving endothelial function, lowering blood pressure, reducing inflammation, and delaying the progression of atherosclerosis. Although the vascular protective effects of gliptins depend on incretins, the contributions of other biologically important endogenous vasoactive substrates of DPP-IV are worthy of consideration from a therapeutic standpoint. Future and ongoing studies should help determine whether these vascular protective effects contribute to improved cardiovascular outcomes in patients with T2DM. The experimental and clinical evidence supporting the vascular protective effects of gliptins is reviewed., (© 2015 Pharmacotherapy Publications, Inc.)

To report three cases of bullous pemphigoid in patients treated with vildagliptin. Case 1: An 86-year-old woman presented with bullous pemphigoid after 1 month of treatment with vildagliptin and metformin. After introduction of clobetasol, the symptoms resolved although vildagliptin was continued. However, the skin lesions reappeared 3 months later. Sustained remission was achieved only after definitive withdrawal of vildagliptin. Case 2: A 79-year-old man presented with bullous pemphigoid after 37-month treatment with gliclazide, vildagliptin and metformin. The disease at first responded to clobetasol but 3 months later the lesions reappeared. They finally regressed when the gliptin was discontinued. Case 3: A 77-year-old woman, treated with gliclazide and vildagliptin for 26 months, presented with bullous pemphigoid, which responded well to discontinuation of the gliptin and topical clobetasol. Gliptins are new molecules for treatment of type 2 diabetes mellitus, which have been suspected of implication in bullous pemphigoid. Such cases have been described in the literature (seven with vildagliptin and three with sitagliptin). In nine of these cases, the gliptin was associated with metformin, but the latter had never been considered responsible. The mechanism implicated in the development of bullous pemphigoid has not yet been clearly identified, but may involve a modified immune response or alteration of the antigenic properties of the epidermal basement membrane. These reports support the risk of bullous pemphigoid in patients exposed to gliptins., (© 2014 Société Française de Pharmacologie et de Thérapeutique.)

Introduction: Dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 receptor agonists are new options in the treatment of type 2 diabetes mellitus. However, due to accumulating reports on the occurrence of acute pancreatitis (AP), a suspicion of an association between incretin-based therapies and pancreatic disease has arisen., Areas Covered: A review of the literature on the safety of incretin-based therapies in regard to AP and pancreatic cancer was undertaken with discussion of potential mechanisms as well as limitations., Expert Opinion: Until now, several preclinical and clinical studies have been published; however, they present conflicting results. Common risk factors, low incidence rates, long latency periods (in regard to pancreatic malignancy), lack of availability of human pancreatic tissues during lifetime among others hamper the confirmation or exclusion of a causal association. The results of the ongoing large randomized controlled trials will add further data. In line with current recommendations by European Medicines Agency and FDA, incretin-based therapies should be discontinued in patients with suspicion of AP, and incretin mimetics should not be administered to patients with a history of AP. However, based on current knowledge, there is no sound reason for depriving type 2 diabetic patients in general of a beneficial and effective therapy. However, this conclusion cannot be final and should be subject to constant reevaluation and, if necessary, change.

Introduction: Dipeptidyl-peptidase-4 (DPP-4) inhibitors are a class of anti-hyperglycemic agents with proven efficacy in patients with type 2 diabetes mellitus (T2DM)., Areas Covered: This review considers the pharmacokinetic profile, adverse effects and drug interactions of DPP-4 inhibitors. DPP-4 inhibitors have certain differences in their structure, metabolism, route of elimination and selectivity for DPP-4 over structurally related enzymes, such as DPP-8/DPP-9. They have a low potential for drug interactions, with the exception of saxagliptin that is largely metabolized by cytochrome CYP3A4/A5. Reports of pancreatitis and pancreatic cancer have raised concerns regarding the safety of DPP-4 inhibitors and are under investigation. Post-marketing surveillance has revealed less common adverse effects, especially a number of skin- and immune-related adverse effects. These issues are covered in the present review., Expert Opinion: DPP-4 inhibitors are useful and efficient drugs. DPP-4 inhibitors have similar mechanism of action and similar efficacy. However, DPP-4 inhibitors have certain differences in their pharmacokinetic properties that may be associated with different clinical effects and adverse event profiles. Although clinical trials indicated a favorable safety profile, post-marketing reports revealed certain safety aspects that need further investigation. Certainly, more research is needed to clarify if the differences among DPP-4 inhibitors could lead to a different clinical and safety profile.