The new insights from DPP-4 inhibitors: their potential immune modulatory function in autoimmune diabetes

Saxagliptin/dapagliflozin is non-inferior to insulin glargine in terms of β-cell function in subjects with latent autoimmune diabetes in adults: A 12-month, randomized, comparator-controlled pilot study

AIM

To compare the efficacy and safety of saxagliptin/dapagliflozin and insulin glargine in people with latent autoimmune diabetes in adults (LADA).

METHODS

In this phase 2b multicentre, open-label, comparator-controlled, parallel-group, non-inferiority study, we randomly assigned 33 people with LADA who had a fasting C-peptide concentration ≥0.2 nmol/L (0.6 ng/mL) to receive 1-year daily treatment with either the combination of saxagliptin (5 mg) plus dapagliflozin (10 mg) or insulin glargine (starting dose: 10 IU), both on top of metformin. The primary outcome was the 2-h mixed meal-stimulated C-peptide area under the curve (AUC), measured 12 months after randomization. Secondary outcomes were glycated haemoglobin (HbA1c) levels, change in body mass index (BMI), and hypoglycaemic events.

RESULTS

In the modified intention-to-treat analysis, the primary outcome was similar in participants assigned to saxagliptin/dapagliflozin or to insulin glargine (median C-peptide AUC: 152.0 ng*min/mL [95% confidence interval {CI} 68.2; 357.4] vs. 122.2 ng*min/mL [95% CI 84.3; 255.8]; p for noninferiority = 0.0087). Participants randomized to saxagliptin/dapagliflozin lost more weight than those randomized to insulin glargine (median BMI change at the end of the study: -0.4 kg/m2 [95% CI -1.6; -0.3] vs. +0.4 kg/m2 [95% CI -0.3; +1.1]; p = 0.0076). No differences in HbA1c or in the number of participants experiencing hypoglycaemic events were found.

CONCLUSIONS

Saxagliptin/dapagliflozin was non-inferior to glargine in terms of β-cell function in this 12-month, small, phase 2b study, enrolling people with LADA with still viable endogenous insulin production. Weight loss was greater with saxagliptin/dapagliflozin, with no differences in glycaemic control or hypoglycaemic risk.

DPP2/7 is a Potential Predictor of Prognosis and Target in Immunotherapy in Colorectal Cancer: An Integrative Multi-omics Analysis

BACKGROUND

Colorectal cancer (CRC) ranks among the leading causes of cancerrelated deaths.

OBJECTIVE

This study aimed to illuminate the relationship between DPP7 (also known as DPP2) and CRC through a combination of bioinformatics and experimental methodologies.

METHODS

A multi-dimensional bioinformatic analysis on DPP7 was executed, covering its expression, survival implications, clinical associations, functional roles, immune interactions, and drug sensitivities. Experimental validations involved siRNA-mediated DPP7 knockdown and various cellular assays.

RESULTS

Data from the Cancer Genome Atlas (TCGA) identified high DPP7 expression in solid CRC tumors, with elevated levels adversely affecting patient prognosis. A shift from the N0 to the N2 stage in CRC was associated with increased DPP7 expression. Functional insights indicated the involvement of DPP7 in cancer progression, particularly in extracellular matrix disassembly. Immunological analyses showed its association with immunosuppressive entities, and in vitro experiments in CRC cell lines underscored its oncogenic attributes.

CONCLUSION

DPP7 could serve as a CRC prognosis marker, functioning as an oncogene and representing a potential immunotherapeutic target.

Immunomodulatory activity of dipeptidyl peptidase-4 inhibitors in immune-related diseases

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.

Dipeptidyl peptidase IV inhibitors and the risk of mycobacterial pulmonary infections in type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (DM) is a risk factor for mycobacterial pulmonary infections (MPI), including tuberculosis (TB) and nontuberculous mycobacterial lung disease (NTM-LD). Dipeptidyl peptidase IV inhibitor (DPP4i), a common DM medication, has an immune-modulation effect that raises concerns about developing MPI. However, there is scarce research on the topic.

METHODS

This retrospective study was conducted in a tertiary-referral center in Taiwan from 2009 to 2016. Patients with type 2 DM who were receiving any DM medication were enrolled. TB and NTM-LD were defined by microbiological criteria. We analyzed the risk of MPI in DPP4i users using Cox proportional hazard regression with adjusted inverse probability of treatment weighting.

RESULTS

A total of 9963 patients were included. Among them, 3931 were classified as DPP4i users, and 6032 patients were DPP4i nonusers. DPP4i users had no increase in incidences of MPI (604 vs. 768 per 100,000 person-years, p = 0.776), NTM-LD (174 vs. 255 per 100,000 person-years, p = 0.228), and TB (542 vs. 449 per 100,000 person-years, p = 0.663) relative to those of DPP4i nonusers. After adjustment, the adjusted hazard ratios for MPI (aHR: 1.07, 95% CI: 0.79-1.45), TB (aHR: 1.15, 95% CI: 0.81-1.64) and NTM-LD (aHR: 0.85, 95% CI: 0.49-1.47) were not significantly increased relative to those of nonusers. The subgroup analysis also showed that DPP4i use did not increase the risk of MPI in different DM severities and comorbidities.

CONCLUSIONS

According to our large cohort study, DPP4i use is safe for patients with type 2 DM and might not increase the risk of MPI.

Management of Invasive Infections in Diabetes Mellitus: A Comprehensive Review

Patients with diabetes often have more invasive infections, which may lead to an increase in morbidity. The hyperglycaemic environment promotes immune dysfunction (such as the deterioration of neutrophil activity, antioxidant system suppression, and compromised innate immunity), micro- and microangiopathies, and neuropathy. A greater number of medical interventions leads to a higher frequency of infections in diabetic patients. Diabetic individuals are susceptible to certain conditions, such as rhino-cerebral mucormycosis or aspergillosis infection. Infections may either be the primary symptom of diabetes mellitus or act as triggers in the intrinsic effects of the disease, such as diabetic ketoacidosis and hypoglycaemia, in addition to increasing morbidity. A thorough diagnosis of the severity and origin of the infection is necessary for effective treatment, which often entails surgery and extensive antibiotic use. Examining the significant issue of infection in individuals with diabetes is crucial. Comprehensive research should examine why infections are more common amongst diabetics and what the preventive treatment strategies could be.

Glucose as a Potential Key to Fuel Inflammation in Rheumatoid Arthritis

Glucose is the most important source of energy and homeostasis. Recent investigations are clarifying that glucose metabolism might be altered in rheumatoid arthritis (RA), which would play a role in the inflammatory phenotype of rheumatoid synovial fibroblasts. It may also play a role in a variety of autoimmune diseases’ pathophysiology by modulating immune responses and modifying autoantigen expressions. The research into glucose and its metabolism could lead to a better understanding of how carbohydrates contribute to the occurrence and duration of RA and other autoimmune diseases.

Emerging Role of Dipeptidyl Peptidase-4 in Autoimmune Disease

Dipeptidyl-peptidase IV (DPP4), originally identified as an aminopeptidase in 1960s, is an ubiquitously expressed protease presented as either a membrane-bound or soluble form. DPP4 cleaves dipeptide off from the N-terminal of its substrates, altering the bioactivity of its substrates. Subsequent studies reveal that DPP4 is also involved in various cellular processes by directly binding to a number of ligands, including adenosine deaminase, CD45, fibronectin, plasminogen, and caveolin-1. In recent years, many novel functions of DPP4, such as promoting fibrosis and mediating virus entry, have been discovered. Due to its implication in fibrotic response and immunoregulation, increasing studies are focusing on the potential role of DPP4 in inflammatory disorders. As a moonlighting protein, DPP4 possesses multiple functions in different types of cells, including both enzymatic and non-enzymatic functions. However, most of the review articles on the role of DPP4 in autoimmune disease were focused on the association between DPP4 enzymatic inhibitors and the risk of autoimmune disease. An updated comprehensive summary of DPP4's immunoregulatory actions including both enzymatic dependent and independent functions is needed. In this article, we will review the recent advances of DPP4 in immune regulation and autoimmune rheumatic disease.

Dipeptidyl peptidase-8 induces Sorafenib resistance via binding with c-Rel to mediate NF-κB signaling in hepatocellular carcinoma

Sorafenib is the important first standard drug for patients with advanced hepatocellular carcinoma (HCC). A major obstacle to successful treatment is Sorafenib resistance. However, the mechanism of Sorafenib resistance is unclear. The present study aimed to determine the involvement of dipeptidyl peptidase-8 (DPP8) in Sorafenib resistance. DPP8 expression was detected using quantitative real-time PCR (qPCR) and western blotting. The effect of DPP8 on Sorafenib resistance was examined using terminal deoxynulceotidyl transferase nick-end-labeling (TUNEL), colony formation, flow cytometry, luciferase reporter, immunofluorescence, and immunoprecipitation (IP) assays. We found that DPP8 mRNA and protein levels were dramatically upregulated in HCC. Gene set enrichment analysis (GSEA) illustrated that DPP8 might be involved in apoptosis regulation. Downregulation of DPP8 substantially promoted the sensitivity of HCC cells to Sorafenib. Further analysis showed that DPP8 might regulate nuclear factor kappa B (NF-κB) signaling, which was confirmed using a luciferase reporter assay. Downregulation of DPP8 decreased the expression levels of downstream genes of the NF-κB pathway. IP showed that DPP8 can interact with NF-κB subunit c-Rel, an important protein of NF-κB signaling. Finally, a drug combination of Sorafenib and Val-boroPro induced higher mortality of HCC cells than Sorafenib alone in DPP8-upregulated cells. Our findings indicated that using the inhibitor Val-boroPro might be a promising method to enhance Sorafenib sensitivity in advanced HCC. This article is protected by copyright. All rights reserved.

The role of autoimmunity in the pathophysiology of type 2 diabetes: Looking at the other side of the moon

Efforts to unravel the pathophysiological mechanisms of type 2 diabetes (T2D) have been traditionally trapped into a metabolic perspective. However, T2D is a phenotypically and pathophysiologically heterogenous disorder, and the need for a tailored approach in its management is becoming increasingly evident. There is emerging evidence that irregular immune responses contribute to the development of hyperglycemia in T2D and, inversely, that insulin resistance is a component of the pathogenesis of autoimmune diabetes. Nevertheless, it has not yet been fully elucidated to what extent the presence of conventional autoimmune markers, such as autoantibodies, in subjects with T2D might affect the natural history of the disease and particularly each response to various treatments. The challenge for future research in the field is the discovery of novel genetic, molecular, or phenotypical indicators that would enable the characterization of specific subpopulations of people with T2D who would benefit most from the addition of immunomodulatory therapies to standard glucose-lowering treatment. This narrative review aims to discuss the plausible mechanisms through which the immune system might be implicated in the development of metabolic disturbances in T2D and obesity and explore a potential role of immunotherapy in the future management of the disorder and its complications.

Effects of the Antidiabetic Drugs Evogliptin and Sitagliptin on the Immune Function of CD26/DPP4 in Th1 Cells

This study aimed to investigate whether the antidiabetic drugs dipeptidyl peptidase 4 (DPP4) inhibitors such as evogliptin and sitagliptin affect the membrane DPP4 (mDPP4) enzymatic activity and immune function of T helper1 (Th1) cells in terms of cytokine expression and cell profiles. The mDPP4 enzymatic activity, cytokine expression, and cell profiles, including cell counts, cell viability, DNA synthesis, and apoptosis, were measured in pokeweed mitogen (PWM)-activated CD4⁺CD26⁺ H9 Th1 cells with or without the DPP4 inhibitors, evogliptin and sitagliptin. PWM treatment alone strongly stimulated the expression of mDPP4 and cytokines such as interleukin (IL)-2, IL-10, tumor necrosis factor-alpha, interferon-gamma, IL-13, and granulocyte-macrophage colony stimulating factor in the CD4⁺CD26⁺ H9 Th1 cells. Evogliptin or sitagliptin treatment potently inhibited mDPP4 activity in a dose-dependent manner but did not affect either the cytokine profile or cell viability in PWM-activated CD4⁺CD26⁺ H9 Th1 cells. These results suggest that, following immune stimulation, Th1 cell signaling pathways for cytokine expression function normally after treatment with evogliptin or sitagliptin, which efficiently inhibit mDPP4 enzymatic activity in Th1 cells.

Emerging Roles of Dipeptidyl Peptidase-4 Inhibitors in Delaying the Progression of Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) results from the immune cell-mediated destruction of functional pancreatic β-cells. In the presymptomatic period, T1DM is characterized by the presence of two or more autoantibodies against the islet cells in patients without glycemic decompensation. Therapeutic strategies that can modify the autoimmune process could slow the progression of T1DM. Dipeptidyl peptidase-4 (DPP-4) or CD26, a multifunctional serine protease with a dual function (regulatory protease and binding protein), can modulate inflammation and immune cell-mediated β-cell destruction. CD26 is involved in T-cell co-stimulation, migration, memory development, thymic maturation, and emigration patterns. DPP-4 degrades the peptide hormones GLP-1 and GIP. In addition to regulating glucose metabolism, DPP-4 exerts anti-apoptotic, regenerative, and proliferative effects to promote β-cell mass expansion. GLP-1 receptor signaling may regulate murine lymphocyte proliferation and maintenance of peripheral regulatory T-cells. In patients with T1DM, the serum DPP-4 activity is upregulated. Several studies have suggested that the upregulated DPP-4 activity is correlated with T1DM pathophysiology. DPP-4, which is preferentially expressed on the Th1 surface, can promote the polarization of Th1 immunity, a prerequisite for T1DM development. CD26 inhibition can suppress T-cell proliferation and Th1 cytokine production and stimulate tumor growth factor beta-1 (TGF-β1) secretion, which plays an important role in the regulation of autoimmunity in T1DM. Studies on humans or animal models of T1DM have suggested that DPP-4 inhibitors can improve β-cell function and attenuate autoimmunity in addition to decreasing insulin dependence. This review summarizes the emerging roles of DPP-4 inhibitors in potentially delaying the progression of T1DM.

Systems pharmacology-based approach for dissecting the mechanisms of pyrazine components in Maotai liquor

Maotai liquor is a typical representative of sauce aroma-style flavor liquors and has been considered to be a precious cultural heritage of the oriental spirit culture. Aroma components are largely responsible for the characteristic aroma of liquor. Pyrazine compound is one of the most important categories of aroma components that affect the flavor of Maotai liquor. However, limited information is available regarding the systemic analysis of pyrazine compounds, especially the pharmacological effects of bioactive pyrazine components. Therefore, in the current study, a systemic analysis approach was provided by integrating absorption, distribution, metabolism, and excretion (ADME) screening, target identification, pharmacological evaluation and pathway analysis to explore the pharmacological mechanism of pyrazine compounds in Maotai liquor. As a result, 17 pyrazine components with adequate pharmacokinetic properties were filtered out using ADME models. Thirty eight potential targets of these active compounds were identified through target prediction. The pharmacological evaluation was proposed to uncover the pharmacological effect of pyrazine compounds in Maotai liquor from the holistic perspective. Finally, the pharmacological effects of the pathways perturbed by potential targets were interpreted based on the pathway analysis. Our study lays the foundation for formulating a comprehensive understanding of the pyrazine compounds in Maotai liquor, which would contribute to the development of Chinese liquor.

Serum Dipeptidyl peptidase-4 level is related to adiposity in type 1 diabetic adolescents

BACKGROUND

Insulin resistance (IR) plays a great role in type 1 diabetes (T1DM) disease process than is commonly recognized. Dipeptidyl peptidase-4 (DPP-4) is an enzyme that deactivates many bioactive peptides involved in glucose regulation.

AIMS

This study evaluates DPP-4 level in adolescent patients with T1DM compared to controls and investigates the relationship between DPP-4 level and IR in these patients.

MATERIALS AND METHODS

We measured serum DPP-4 level in 50 patients with T1DM recruited from the Diabetes Endocrine Metabolism Pediatric Unit, and in 80 healthy controls. IR was assessed by the equation for estimated glucose disposal rate (eGDR). Biochemical evaluation including glycated haemoglobin (HbA1C) and lipid profile were included.

RESULTS

IR was found in 80% of patients with T1DM. DPP-4 was significantly higher in control group than patients with T1DM. Patients with T1DM were classified into 3 groups according to DPP-4 tertiles showing significant increase in BMI SDS and total cholesterol across the 3 groups. Significant correlation was found between DPP-4 levels and insulin dose. DPP-4 was significantly higher in patients with T1DM with good glycemic control.

CONCLUSION

In sample of individuals researched by us, serum DPP-4 was related to adiposity and not to the hyperglycemia in patients with T1DM. Larger sample should be researched to make firm conclusions.

The Chiral Bioconversion and Pharmacokinetic Analysis of Trelagliptin in Beagle Dog Plasma by LC-MS/MS

A simple and enantioselective method was developed and validated for the simultaneous determination of (R)- and (S)-trelagliptin in beagle dog plasma by chiral liquid chromatography tandem mass spectrometry. Trelagliptin enantiomers and (R)-rabeprazole (as internal standard, IS) were extracted from plasma samples by liquid-liquid extraction and separated on a CHIRALCEL OX-3R column using acetonitrile-5 ammonium bicarbonate as the mobile phase in gradient elution mode. The multiple reactions monitoring transitions of m/z 358.1→341.2 and 359.9→150.1 were used to quantify trelagliptin enantiomers and IS, respectively. This method was validated for sensitivity, specificity, linearity, precision, accuracy and stability of specific analytes under various conditions. And it was successfully applied to evaluating the pharmacokinetic profile of trelagliptin enantiomers in beagle dogs after single intravenous administration of (R)-trelagliptin injection (at 1 mg/kg) and oral administration (at 6.7 mg/kg). In this study, no chiral bioconversion of (R)-trelagliptin to (S)-trelagliptin in beagle dog plasma was observed. The absolute bioavailability of (R)-trelagliptin was identified to be 128.2%.

A network pharmacology-based strategy for predicting anti-inflammatory targets of ephedra in treating asthma

Asthma, the most common chronic respiratory disease in the world, is involved in a sustained inflammatory response caused by a variety of immune cells. Ephedra with multi-target, multi-pathway functions is an effective treatment for asthma. However, the ingredients and anti-inflammatory targets of ephedra in treating asthma are unclear. Therefore, there is a need for further research. Ephedra-related and anti-inflammatory targets were found and then combined to get intersection, which represented potential anti-inflammatory targets of ephedra. Moreover, compound-anti-inflammatory target and asthma-target protein-protein interaction network were merged to get the protein-protein interaction network intersection and core genes in asthma-target protein-protein interaction network. For the anti-inflammatory targets of ephedra in treating asthma, Gene Ontology and pathway analysis were executed to confirm gene functions of ephedra in antagonizing inflammation of asthma. Finally, molecular docking, qRT-PCR, WB and ELISA were performed to assess the binding activities between the compounds and anti-inflammatory targets of ephedra in treating asthma. Critical compounds and anti-inflammatory targets of ephedra in treating asthma were identified, including quercetin, luteolin, kempferol, naringenin, beta-sitosterol, SELE, IL-2 and CXCL10. The biological processes of anti-inflammatory targets of ephedra in treating asthma were involved in immune response, inflammatory response, cell-cell signaling and response to lipopolysaccharide. Moreover, 22 pathways were obtained and we proved that critical compounds inhabited the expression of SELE, IL-2 and CXCL10 at mRNA and protein levels.

Therapeutic approaches for latent autoimmune diabetes in adults: One size does not fit all

Recent advances in the understanding of latent autoimmune diabetes in adults (LADA) pathophysiology make it increasingly evident that people with LADA comprise a heterogenous group of patients. This makes the establishment of a standard treatment algorithm challenging. On top of its glucose-lowering action, insulin may exert anti-inflammatory effects, rendering it an attractive therapeutic choice for a type of diabetes in which autoinflammation and beta cell insufficiency play major pathogenetic roles. However, there is growing evidence that other antidiabetic drugs, such as metformin, dipeptidyl peptidase-4 inhibitors, glucagon-like peptide-1 receptor agonists, and thiazolidinediones, might have a role in optimizing glycemic control and preserving beta cell function in individuals with LADA, either alone or in combination with insulin. Although most of these drugs have been routinely used in the daily clinical setting for years, large prospective randomized trials are needed to assess whether they are capable of delaying progression to insulin dependence as well as their effects on diabetic complications. The aim of the present review is to discuss the current state and future perspectives of LADA therapy, emphasizing the need for individualized and patient-centered therapeutic approaches.

Past, present and future of latent autoimmune diabetes in adults

Latent autoimmune diabetes in adults (LADA) is the most common form of autoimmune diabetes diagnosed in adults. Similar to type 1 diabetes, the prevalence of LADA is impacted by ethnicity and geography. LADA is characterized by β cell loss due to autoimmunity and insulin resistance and has highly heterogeneous clinical features, autoimmunity, and genetics in a glutamic acid decarboxylase antibody (GADA) titre-dependent manner, suggesting LADA is part of a continuum spectrum between type 1 and type 2 diabetes. Although LADA is the most frequent form of autoimmune diabetes diagnosed in adults, clinical trials involving LADA are scarce. Here we review the recent advancements in LADA epidemiology, clinical features, pathogenesis, and interventions. We also highlight the environmental factors that are thought to play an important role in addition to genetics in the pathogenesis of LADA. In the future, high-throughput molecular profiles might shed light on the nature of LADA among the wide spectrum of diabetes and offer new opportunities to identify novel LADA-specific biomarkers.

DPP8 is a novel therapeutic target for multiple myeloma

Dipeptidyl peptidases (DPPs) are proteolytic enzymes that are ideal therapeutic targets in human diseases. Indeed, DPP4 inhibitors are widely used in clinical practice as anti-diabetic agents. In this paper, we show that DPP4 inhibitors also induced cell death in multiple human myeloma cells. Among five DPP4 inhibitors, only two of them, vildagliptin and saxagliptin, exhibited apparent cytotoxic effects on myeloma cell lines, without any difference in suppression of DPP4 activity. As these two DPP4 inhibitors are known to have off-target effects against DPP8/9, we employed the specific DPP8/9 inhibitor 1G244. 1G244 demonstrated anti-myeloma effects on several cell lines and CD138+ cells from patients as well as in murine xenograft model. Through siRNA silencing approach, we further confirmed that DPP8 but not DPP9 is a key molecule in inducing cell death induced by DPP8/9 inhibition. In fact, the expression of DPP8 in CD38+ cells from myeloma patients was higher than that of healthy volunteers. DPP8/9 inhibition induced apoptosis, as evidenced by activated form of PARP, caspases-3 and was suppressed by the pan-caspase inhibitor Z-VAD-FMK. Taken together, these results indicate that DPP8 is a novel therapeutic target for myeloma treatment.

Systematic Analysis of the Pharmacological Effects of Alcoholic Components in Maotai

Maotai liquor is one of the most famous traditional Chinese distilled liquor enjoyed by many people all over the world for its unique production method, impressive liquor quality, and soy sauce-like and roasted aroma style. It is known that aroma characteristics of liquor mainly depend on the aroma compounds. Alcohols as one of the most important categories of aroma components have been determined in Maotai liquor. However, the systemic analysis of alcoholic compounds in liquor is limited, especially the active alcoholic components and their pharmacological effects. Therefore, in this study, a systemic analysis method was proposed by combining in silico absorption, distribution, metabolism, and excretion (ADME) evaluation, target fishing, network pharmacology technology, pathway analysis, and experimental verification to interpret the pharmacological mechanism of alcoholic compounds in Maotai liquor. Finally, 15 compounds with favorable pharmacokinetic profiles were screened through in silico ADME models. Thirty-eight related targets of these active compounds were identified by target prediction method. The network pharmacology and pathway analysis were developed to clarify the pharmacological effect of alcoholic compounds in Maotai liquor at the system and pathway level. Moreover, the key active compounds were validated by in vitro experiments that verified the effectiveness of our methods. Our study provides a novel approach to systematically analyze the pharmacological effect of alcoholic compounds in Maotai liquor, which would be beneficial for promoting the in-depth study of various liquors. PRACTICAL APPLICATION: Maotai liquor is popularly enjoyed in the world for a very long time. However, the systemic analysis of compounds in liquor is limited. Our systematic analysis approach was developed to explore the bioactive ingredients and their related target proteins as well as the pharmacological effects of Maotai liquor. This will provide a new method to understand the pharmacological mechanisms of compounds in various liquors at the systems level, so as to promote the development of liquors and to increase the public awareness of science about alcohol consumption.

Acquired Hemophilia A Associated with Dipeptidyl Peptidase-4 Inhibitors for the Treatment of Type 2 Diabetes Mellitus: A Single-Center Case Series in Japan

Herein we describe four patients with acquired hemophilia A (AHA) caused by factor VIII (FVIII) inhibitor and histories of dipeptidyl peptidase-4 inhibitor (DPP4-I) treatment for diabetes mellitus (DM). Drug exposure can cause a breakdown of immune tolerance to FVIII associated with CD4 T cells, resulting in the induction of autoantibodies against FVIII. In patient 1 in the present series, FVIII inhibitor disappeared after DPP4-I treatment. The DPP4-I treatment was stopped faster in patient 1 than it was in patient 2, whose FVIII inhibitor titer was higher than patient 1's. Two patients died: patient 3 due to brain infarction after recurrence associated with the development of sigmoid colon rupture, and patient 4 due to multiple organ failure associated with Clostridium difficile colitis. DPP4-I treatment may create an ideal environment for the induction of new antibodies and AHA onset associated with tumor necrosis factor-α reduction. These are the first reported cases of the potential development and/or prolonging of AHA after DDP4-I treatment for DM, and they suggest possible disease associations.

Dipeptidyl dipeptidase-4 inhibitor recovered ischemia through an increase in vasculogenic endothelial progenitor cells and regeneration-associated cells in diet-induced obese mice

Metabolic syndrome (MS), overlapping type 2 diabetes, hyperlipidemia, and/or hypertension, owing to high-fat diet, poses risk for cardiovascular disease. A critical feature associated with such risk is the functional impairment of endothelial progenitor cells (EPCs). Dipeptidyl dipeptidase-4 inhibitors (DPP-4 i) not only inhibit degradation of incretins to control blood glucose levels, but also improve EPC bioactivity and induce anti-inflammatory effects in tissues. In the present study, we investigated the effects of such an inhibitor, MK-06266, in an ischemia model of MS using diet-induced obese (DIO) mice. EPC bioactivity was examined in MK-0626-administered DIO mice and a non-treated control group, using an EPC colony-forming assay and bone marrow cKit⁺ Sca-1⁺ lineage-cells, and peripheral blood-mononuclear cells. Our results showed that, in vitro, the effect of MK-0626 treatment on EPC bioactivities and differentiation was superior compared to the control. Furthermore, microvascular density and pericyte-recruited arteriole number increased in MK-0626-administered mice, but not in the control group. Lineage profiling of isolated cells from ischemic tissues revealed that MK-0626 administration has an inhibitory effect on unproductive inflammation. This occurred via a decrease in the influx of total blood cells and pro-inflammatory cells such as neutrophils, total macrophages, M1, total T-cells, cytotoxic T-cells, and B-cells, with a concomitant increase in number of regeneration-associated cells, such as M2/M ratio and T_reg/T-helper. Laser Doppler analysis revealed that at day 14 after ischemic injury, blood perfusion in hindlimb was greater in MK-0626-treated DIO mice, but not in control. In conclusion, the DPP-4 i had a positive effect on EPC differentiation in MS model of DIO mice. Following ischemic injury, DPP-4 i sharply reduced recruitment of pro-inflammatory cells into ischemic tissue and triggered regeneration and reparation, making it a promising therapeutic agent for MS treatment.

Altered T-cell subsets and transcription factors in latent autoimmune diabetes in adults taking sitagliptin, a dipeptidyl peptidase-4 inhibitor: A 1-year open-label randomized controlled trial

AIMS/INTRODUCTION

Dipeptidyl peptidase-4 inhibitor has been proven to improve glycemic control and β-cell function in latent autoimmune diabetes in adults (LADA). The potential immune modulation mechanism is still unknown. Thus, we tested T-lymphocyte subsets and expression of relevant transcription factors in LADA patients with sitagliptin intervention for up to 1-year.

MATERIALS AND METHODS

A total of 40 LADA patients were randomly assigned to sitagliptin and/or insulin treatment (SITA group; n = 20) or insulin alone treatment (CONT group; n = 20). Peripheral blood mononuclear cells were isolated at baseline, 6 months and 12 months. The percentage of T-lymphocyte subsets (T helper 1, T helper 2, T helper 17 and regulatory T cells) tested by flow cytometry, and the messenger ribonucleic acid expression (T box expressed in T cells [T-BET], GATA binding protein 3 [GATA3], forkhead box protein 3 [FOXP3] and related orphan receptor C [RORC]) tested by real-time polymerase chain reaction were determined at baseline, 6 months and 12 months.

RESULTS

The percentage of regulatory T cells in the SITA group was significantly lower than that of the CONT group at baseline. The percentage of T helper 2 cells was higher than that of the CONT group at 6 months and 12 months. At 12 months, the percentage of T helper 17 cells was lower in the SITA group than that of the CONT group. After a 1-year visit, the messenger ribonucleic acid expression levels of T-BET expressed in T cells and RORC in the SITA group were significantly lower than at baseline. Whereas that of RORC in the CONT group were significantly lower than that at baseline.

CONCLUSIONS

The data confirmed that sitagliptin altered the phenotype of T cells and downregulated the expression of T-BET and RORC in LADA patients, and ameliorated glycemic control in LADA patients.

Incretin-based therapies for patients with type 1 diabetes: a meta-analysis

OBJECTIVE

Combined treatment with an incretin-based drug, such as a glucagon-like peptide 1 receptor agonist (GLP-1 RA) or a dipeptidyl peptidase-4 (DPP-4) inhibitor, and basal insulin is a new strategy for improving glucose control in type 1 diabetes mellitus (T1DM). We performed a meta-analysis to assess the effect of this combined treatment on glycaemic control, insulin dose, severe hypoglycaemia, weight gain and gastrointestinal side effects in T1DM patients.

METHODS

We searched PubMed, EMBASE and the Cochrane Library for relevant studies published before July 16, 2018. The primary outcome was glycosylated haemoglobin (HbA1c). Secondary outcomes included total daily insulin dose, body weight, severe hypoglycaemia and gastrointestinal side effects.

RESULTS

Nine randomized controlled trials (RCTs) involving 2389 patients were ultimately included in the meta-analysis. The pooled data suggested that incretin-based therapy was associated with a reduction in HbA1c levels (weighted mean difference (WMD) -0.17%, 95% confidence interval (CI) -0.24 to -0.11, P < 0.001), total daily insulin dose (WMD -5.53 IU/day, 95% CI -8.89 to -2.17, P = 0.001) and body weight (WMD -3.24 kg, 95% CI -4.43 to -2.04, P < 0.001). Incretins did not increase the risk of severe hypoglycaemia (odds ratio (OR) 0.83, 95% CI 0.60-1.16, P = 0.287) but increased the occurrence of gastrointestinal side effects (OR 3.46, 95% CI 2.20-5.45, P < 0.001).

CONCLUSIONS

In T1DM patients, GLP-1 RAs, but not DPP-4 inhibitors, combined with insulin appear to be an effective therapy but may increase the occurrence of gastrointestinal side effects.

Biological function of dipeptidyl peptidase-4 on type 2 diabetes patients and diabetic mice

BACKGROUND

Type 2 diabetes (TD2) is a sustained metabolic disorder, characterized by high blood glucose, insulin resistance (IR). Dipeptidyl peptidase-4 (DPP4) functions as an antigenic enzyme involved in hyperglycaemia, oxidative stress, and inflammation-associated IR. Therefore, association between DPP4 and TD2 warrants to be investigated.

METHODS

In this study, blood samples of clinically diagnosed TD2 patients were harvested for biochemical tests. In addition, diabetic mice induced by high-fat diet (HFD) and single dose of streptozotocin (STZ) were used to assess the biological characteristics of DPP4 through biochemical and enzyme-linked immunosorbent assay (ELISA) tests, immunofluorescence staining, and western blot assay.

RESULTS

Compared to controls, the clinical data of patients with TD2 resulted in increased contents of fasting blood glucose (FBG), glycated hemoglobin (HbA1c), homeostatic model assessment (HOMA)-IR, blood lipids of triglyceride (TG), total cholesterol (TC), low-density lipoprotein (LDL-C), and interleukin 6 (IL6) in plasma samples (p < 0.05). Notably, blood levels of DPP4 in TD2 patients were increased significantly in comparison to that in non-diabetic adults (p < 0.01). In animal study, diabetic mice showed increased levels of glucose, insulin, lipids, DPP4 activity in sera. Visibly, hepatocellular DPP4 expression was up-regulated in diabetic mice. Interestingly, DPP4 inhibitor-treated mice showed significantly reduced DPP4 expression in serum (p < 0.01), and lowered DPP4-positive cells and protein content in the liver were observed when compared to those in diabetic mice (p < 0.01).

CONCLUSIONS

Collectively, these findings reveal that DPP4 biomolecule may be positively associated with TD2 development, and the underlying mechanism may be attributed to activation of DPP4 expression in liver cells.

Dipeptidyl peptidase-4(DPP-4) inhibitors: promising new agents for autoimmune diabetes

Dipeptidyl peptidase-4 (DPP-4) inhibitors constitute a novel class of anti-diabetic agents confirmed to improve glycemic control and preserve β-cell function in type 2 diabetes. Three major large-scale studies, EXAMINE, SAVOR-TIMI 53, and TECOS, have confirmed the cardiovascular safety profile of DPP-4 inhibitors. Based on these results, DPP-4 inhibitors have gained widespread use in type 2 diabetes treatment. It is currently unknown, however, whether DPP-4 inhibitors have similar therapeutic efficacy against autoimmune diabetes. Several in vitro and in vivo studies have addressed this issue, but the results remain controversial. In this review, we summarize experimental findings and preliminary clinical trial results, and identify potentially effective immune modulation targets of DPP-4 inhibitors for autoimmune diabetes.

Association between dipeptidyl peptidase-4 inhibitors and urinary tract infection in elderly patients: A retrospective cohort study

PURPOSE

Dipeptidyl peptidase-4 (DPP-4) inhibitors are a new class of antidiabetic drugs. Although they have been reported to increase the risk of infection, the findings are controversial. Given that urinary tract infections (UTIs) are common in the elderly, we conducted a retrospective cohort study by using health care insurance claims data, to elucidate the association between the DPP-4 inhibitors and the incidence of UTI in latter-stage elderly patients.

METHODS

We analyzed 25,111 Japanese patients aged 75 years and older between the fiscal years 2011 and 2016. Patients using DPP-4 inhibitors and sulfonylureas (SUs) were matched at a 1:1 ratio using propensity scoring. The Incidence rate ratio (IRR) of UTI was compared between users of SUs and users of DPP-4 inhibitors by Poisson regression. Moreover, subgroup analyses stratified by sex were conducted to evaluate whether the combination of prostatic hyperplasia and DPP-4 inhibitors is associated with the incidence of UTI in male patients.

RESULTS

The use of DPP-4 inhibitors was associated with an increased risk of UTI (adjusted IRR 1.23, 95% CI [1.04-1.45]). After propensity score matching, the association remained significant (adjusted IRR 1.28, 95% CI [1.05-1.56]). Moreover, elderly male patients with prostatic hyperplasia who received DPP-4 inhibitors had a higher risk of UTI than SU users without prostatic hyperplasia (Matched: crude IRR 2.90, 95% CI [1.78-4.71]; adjusted IRR 2.32, 95% CI [1.40-3.84]).

CONCLUSIONS

The long-term use of DPP-4 inhibitors by elderly patients, particularly male patients with prostatic hyperplasia, may increase the risk of UTI.

Dipeptidyl peptidase-4 inhibitors have adverse effects for the proliferation of human T cells

Dipeptidyl peptidase-4 (DPP-4) is a critical molecule for the metabolism of incretins. In addition, DPP-4 is known as CD26, the receptor of T cells, and plays important role in activation of T cells. Recently, DPP-4 inhibitors (DPP4i) are reported to have several immunologic effects beyond glycemic control. DPP4i seem to have anti-inflammatory effects in patients with type 2 diabetes. This might be direct effects on T cells. However, the close mechanism is not clear. To evaluate the possibility, we performed ex vivo assays by using primarily human CD4⁺ T cells (CD4) and CD8⁺ T cells (CD8). We purified primary naïve CD4 and CD8 from human peripheral blood. Then, we evaluated the effect of DPP4i on the proliferation of naïve T cells and the cytokine production in ex vivo experiments. The proliferation of CD4 and CD8 were suppressed by adding DPP4i in a dose dependent manner. However, DPP4i did not inhibit cytokine production from CD4. It was revealed by phospho-flow that the T cell receptor (TCR) signaling was attenuated in the presence of DPP4i. Taken together, DPP4i modulated TCR signaling, which contributed to attenuate the proliferation of CD4 and CD8. DPP4i have adverse effects for the proliferation of human T cells.

Herpes Zoster and Diabetes Mellitus: A Review

Accumulating evidence suggests that diabetes mellitus (DM) represents an important risk factor for both herpes zoster and post-herpetic neuralgia. Moreover, post-herpetic neuralgia appears to be more severe and persistent in diabetic patients. On the other hand, a novel vaccine against varicella-zoster virus (VZV) was recently introduced in clinical practice. Given the increased risk and severity of herpes zoster infection in patients with DM, this vaccine might be useful in this population. However, there are limited data regarding the efficacy and safety of vaccination against herpes zoster in the diabetic population. The aim of the present review is to discuss the incidence and consequences of herpes zoster infection in DM and to comment on the role of vaccination against VZV in these patients.

Pharmacological Treatment in Diabetes Mellitus Type 1 - Insulin and What Else?

The basis of treatment in autoimmune diabetes is insulin therapy; however, many clinical cases have proven that this method does not solve all problems. Trials of causal treatment including blocking the autoimmune processes and insulin-producing cells transplants were carried out. Those methods require more research to be concerned as efficient and safe ways of treatment in type 1 diabetes. The use of non-insulin adjunct treatment is a new trend. It has been successfully used in laboratories as well as clinical trials. Metformin is the most widely used drug, together with sodium-glucose co-transporters 2 (SGLT2) inhibitors, amylin analogues, glucagon-like peptide 1 (GLP-1) receptor agonists, and dipeptidyl peptidase-4 (DPP-4) inhibitors. The results of administration of these medicaments give good outcomes in patients with diabetes mellitus type 1. Most likely, in the near future, they will progressively be used in both adult and adolescent patients with type 1 diabetes. Further multicenter, randomized studies are required to evaluate the efficacy of treatment and long term safety of these drugs.

The paradox of Th17 cell functions in tumor immunity

Immune system acts as a host defensive mechanism protecting against attacking pathogens and transformed cells, including cancer cells. Th17 cells are a specific subset of T helper lymphocytes determined by high secretion of IL-17 and other inflammatory cytokines. Th17 cells increase tumor progression by activating angiogenesis and immunosuppressive activities. They can also mediate antitumor immune responses through recruiting immune cells into tumors, stimulating effector CD8+ T cells, or surprisingly by altering toward Th1 phenotype and producing IFN-γ, so Th17 cells are supposed as a double-edged sword in cancer. A comprehensive approach to indicating the activity of Th17 cells in tumor progression could help in the planning of new therapeutic approaches specially targeting Th17 cells in cancer.

Dipeptidyl peptidase-4 (DPP-4) inhibition with linagliptin reduces western diet-induced myocardial TRAF3IP2 expression, inflammation and fibrosis in female mice

Background

Diastolic dysfunction (DD), a hallmark of obesity and primary defect in heart failure with preserved ejection fraction, is a predictor of future cardiovascular events. We previously reported that linagliptin, a dipeptidyl peptidase-4 inhibitor, improved DD in Zucker Obese rats, a genetic model of obesity and hypertension. Here we investigated the cardioprotective effects of linagliptin on development of DD in western diet (WD)-fed mice, a clinically relevant model of overnutrition and activation of the renin-angiotensin-aldosterone system.

Methods

Female C56Bl/6 J mice were fed an obesogenic WD high in fat and simple sugars, and supplemented or not with linagliptin for 16 weeks.

Results

WD induced oxidative stress, inflammation, upregulation of Angiotensin II type 1 receptor and mineralocorticoid receptor (MR) expression, interstitial fibrosis, ultrastructural abnormalities and DD. Linagliptin inhibited cardiac DPP-4 activity and prevented molecular impairments and associated functional and structural abnormalities. Further, WD upregulated the expression of TRAF3IP2, a cytoplasmic adapter molecule and a regulator of multiple inflammatory mediators. Linagliptin inhibited its expression, activation of its downstream signaling intermediates NF-κB, AP-1 and p38-MAPK, and induction of multiple inflammatory mediators and growth factors that are known to contribute to development and progression of hypertrophy, fibrosis and contractile dysfunction. Linagliptin also inhibited WD-induced collagens I and III expression. Supporting these in vivo observations, linagliptin inhibited aldosterone-mediated MR-dependent oxidative stress, upregulation of TRAF3IP2, proinflammatory cytokine, and growth factor expression, and collagen induction in cultured primary cardiac fibroblasts. More importantly, linagliptin inhibited aldosterone-induced fibroblast activation and migration.

Conclusions

Together, these in vivo and in vitro results suggest that inhibition of DPP-4 activity by linagliptin reverses WD-induced DD, possibly by targeting TRAF3IP2 expression and its downstream inflammatory signaling.

Four-year clinical remission of type 1 diabetes mellitus in two patients treated with sitagliptin and vitamin D3

Type 1 diabetes mellitus (T1DM) is a chronic disease characterized by autoimmune destruction of pancreatic beta cells and inadequate insulin production. Remission criteria in T1DM take into account serum levels of C-peptide and glycosylated hemoglobin, as well as the dose of insulin administered to the patient. However, remission of T1DM lasting longer than 1 year is rare. We describe here the cases of two young women who presented with positive glutamic acid decarboxylase (GAD) antibody and classic clinical manifestations of T1DM. Both patients had a prior history of Hashimoto’s thyroiditis. They were initially treated with a basal-bolus regimen of insulin (glargine and lispro/glulisine). Once their blood glucose levels were controlled, they were started on oral sitagliptin 100 mg and vitamin D3 5000 IU daily. After this therapy, both patients achieved clinical diabetes remission for 4 years, along with a decrease in anti-GAD antibody levels. These benefits were probably associated with immunological effects of these medications. Inhibition of dipeptidyl peptidase 4 (DPP-4) in animal models deregulates Th1 immune response, increases secretion of Th2 cytokines, activates CD4⁺CD25⁺FoxP3⁺ regulatory T-cells and prevents IL-17 production. Vitamin D3 also activates CD4⁺CD25⁺FoxP3⁺ regulatory T-cells, and these medications combined can improve the immune response in patients with new-onset T1DM and probably promote sustained clinical remission.

The effect of dipeptidyl peptidase-IV inhibition on circulating T cell subpopulations in patients with type 2 diabetes mellitus

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.

Efficacy and safety of live varicella zoster vaccine in diabetes: a randomized, double-blind, placebo-controlled trial

AIMS

To elucidate varicella zoster virus (VZV)-specific cell-mediated immunity and humoral immunogenicity against live attenuated Oka varicella zoster vaccine concurrently vaccinated with 23-valent pneumococcal polysaccharide vaccine (PPSV23) in elderly people with diabetes mellitus.

METHODS

This double-blind randomized controlled single-centre study of 60-70-year-old people with diabetes compared immunity and safety profiles 3 months after one dose of varicella zoster vaccine or placebo. PPSV23 was immunized simultaneously. Primary analysis evaluated cell-mediated immunity using the VZV skin test. Secondary analyses were a VZV interferon-γ enzyme-linked immunospot (ELISPOT) assay and immunoadherence haemagglutination test. Adverse experiences were recorded using diary questionnaires.

RESULTS

By intent-to-treat analysis, 27 participants with diabetes who had been administered the vaccine were compared with 27 participants who were given a placebo. Changes in skin test scores were 0.41 ± 0.80 and 0.11 ± 0.93 (P = 0.2155), and geometric mean fold rises of the ELISPOT counts were 1.2 [95% confidence interval (CI) 0.2, 7.9] and 1.2 (95% CI 0.2, 7.3) (P = 0.989) in the vaccine and placebo groups, respectively. The geometric mean titre did not increase 3 months after vaccination in either group. No vaccination-related severe adverse experience was reported and no participant developed herpes zoster.

DISCUSSION

Our previous results demonstrated that varicella zoster vaccine safely enhanced VZV-specific immunity in elderly people with or without diabetes. The results of this study showed that varicella zoster vaccine can be used safely, but it cannot boost virus-specific immunity in elderly people with diabetes when administered with concurrent PPSV23. Alternative strategies are needed to prevent VZV-associated diseases in this population.

Unravelling the immunological roles of dipeptidyl peptidase 4 (DPP4) activity and/or structure homologue (DASH) proteins

Dipeptidyl peptidase (DPP) 4 (CD26, DPP4) is a multi-functional protein involved in T cell activation by co-stimulation via its association with adenosine deaminase (ADA), caveolin-1, CARMA-1, CD45, mannose-6-phosphate/insulin growth factor-II receptor (M6P/IGFII-R) and C-X-C motif receptor 4 (CXC-R4). The proline-specific dipeptidyl peptidase also modulates the bioactivity of several chemokines. However, a number of enzymes displaying either DPP4-like activities or representing structural homologues have been discovered in the past two decades and are referred to as DPP4 activity and/or structure homologue (DASH) proteins. Apart from DPP4, DASH proteins include fibroblast activation protein alpha (FAP), DPP8, DPP9, DPP4-like protein 1 (DPL1, DPP6, DPPX L, DPPX S), DPP4-like protein 2 (DPL2, DPP10) from the DPP4-gene family S9b and structurally unrelated enzyme DPP2, displaying DPP4-like activity. In contrast, DPP6 and DPP10 lack enzymatic DPP4-like activity. These DASH proteins play important roles in the immune system involving quiescence (DPP2), proliferation (DPP8/DPP9), antigen-presenting (DPP9), co-stimulation (DPP4), T cell activation (DPP4), signal transduction (DPP4, DPP8 and DPP9), differentiation (DPP4, DPP8) and tissue remodelling (DPP4, FAP). Thus, they are involved in many pathophysiological processes and have therefore been proposed for potential biomarkers or even drug targets in various cancers (DPP4 and FAP) and inflammatory diseases (DPP4, DPP8/DPP9). However, they also pose the challenge of drug selectivity concerning other DASH members for better efficacy and/or avoidance of unwanted side effects. Therefore, this review unravels the complex roles of DASH proteins in immunology.

Significant elevation of serum dipeptidyl peptidase-4 activity in young-adult type 1 diabetes

AIMS

Currently, inhibition of dipeptidyl peptidase-4 (DPP-4) is widely used in the treatment of type 2 diabetes. Application of this strategy is awaited as a new therapeutic approach for type 1 diabetes, but the scientific basis is still lacking. This report describes the evaluation of serum DPP-4 activity in type 1 diabetes compared with control subjects, and assessment of relationships between DPP-4 activity and diabetic complication markers and metabolic variables in type 1 diabetes.

METHODS

We examined serum DPP-4 activity in Japanese young-adult type 1 diabetes (n=76, females 69.7%, age 30.9 ± 6.2 years, duration of diabetes 16.5 ± 11.1 years; mean ± SD) and healthy controls (n=22). Association of the enzymatic activity with diabetic micro- and macro- vascular complication markers and clinical parameters was also assessed.

RESULTS

Subjects with type 1 diabetes displayed significantly higher serum DPP-4 activity than healthy controls (relative value, control: 1.00 ± 0.28, T1D, 1.29 ± 0.38; p=0.0011) independent of other clinical parameters. In type 1 diabetes, DPP-4 activity was positively correlated with duration of diabetes (r=0.248, p=0.031), while not correlated with HbA1c level. In univariate correlation analysis of diabetic complication markers and other metabolic parameters, coefficient of variation of R-R intervals (CVR-R) and gamma (γ)-glutamyltransferase (GGT) levels were correlated with DPP-4 activity. GGT was extracted as an independent variable of DPP-4 activity in multivariate analysis (β=0.213, p=0.035).

CONCLUSIONS

Serum DPP-4 activity is significantly elevated in Japanese type 1 diabetes, suggesting pathophysiological significance of the enzyme in type 1 diabetes.

Network pharmacology-based prediction of the active ingredients and potential targets of Mahuang Fuzi Xixin decoction for application to allergic rhinitis

ETHNOPHARMACOLOGICAL RELEVANCE

Certain herbal formulae from Traditional Chinese Medicine (TCM) are effective for treating and preventing diseases in clinical practice. Mahuang fuzi Xixin Decoction (MFXD) is a TCM that is used to treat allergic rhinitis (AR); however, the active ingredients and potential targets of its action against AR remain unclear. Therefore, further investigation is required.

METHODS

A network pharmacology approach comprising drug-likeness evaluation, oral bioavailability prediction, multiple drug target prediction, and network analysis has been used in this study.

RESULTS

The comprehensive systematic approach was successfully to indentify 41 bioactive ingredients in MFXD, while 37 potential targets hit by these ingredients related to AR. Moreover, wherein four predicted ingredients possess anti-inflammatory effects were found by this technique.

CONCLUSIONS

Our works successfully predict the active ingredients and potential targets of MFXD for application to allergic rhinitis and helps to illustrate mechanism of action on a systematic level. This study not only provides new insights into the chemical basis and pharmacology of MFXD but also demonstrates a feasible method for discovering potential drugs from herbal medicine.

Sitagliptin, a DPP-4 inhibitor, alters the subsets of circulating CD4+ T cells in patients with type 2 diabetes

OBJECTIVE

CD26/DPP-4 is highly expressed by T cells, especially CD4+ T cells (T helper cells; Th) and may regulate the differentiation, maturation, or proliferation of these cells. We investigated the effects of sitagliptin, a DPP-4 inhibitor, on the absolute number and percentage of various subsets of circulating CD4+ T cells in patients with type 2 diabetes.

METHODS

We enrolled 30 consecutive patients (16 women and 14 men) with type 2 diabetes in a prospective, randomized, open-label, blinded endpoint study. Eligible participants were randomly assigned at a 2:1 ratio to either a sitagliptin group (sitagliptin at 50mg/day) or an active control group (glimepiride at 1mg/day). Patients were followed for 12 weeks with monthly review. Peripheral blood mononuclear cells were examined by flow cytometry for intracellular expression of cytokines (IFN-γ as a marker of Th1cells, IL-4 for Th2 cells, and IL-17 for Th17 cells) and for expression of CD4, CD25, and Foxp3 (regulatory T cells [Treg]).

RESULTS

Both groups showed similar improvement of glycemic control. The total number of CD4+ T cells was decreased by treatment with sitagliptin, while it did not change in the control group. The number and percentage of Th17 cells and Treg cells both decreased significantly in the sitagliptin group, but not in the control group. There was a significant positive correlation between changes in the percentage of Th17 cells and Treg cells after treatment with sitagliptin.

CONCLUSIONS

Treatment with sitagliptin for 12 weeks reduced the number of circulating CD4+ T cells, especially Th17 and Treg cells, in patients with type 2 diabetes.

Type 1 Diabetes Prevention in NOD Mice by Targeting DPPIV/CD26 Is Associated with Changes in CD8⁺T Effector Memory Subset

CD26 is a T cell activation marker consisting in a type II transmembrane glycoprotein with dipeptidyl peptidase IV (DPPIV) activity in its extracellular domain. It has been described that DPPIV inhibition delays the onset of type 1 diabetes and reverses the disease in non-obese diabetic (NOD) mice. The aim of the present study was to assess the effect of MK626, a DPPIV inhibitor, in type 1 diabetes incidence and in T lymphocyte subsets at central and peripheral compartments. Pre-diabetic NOD mice were treated with MK626. Diabetes incidence, insulitis score, and phenotyping of T lymphocytes in the thymus, spleen and pancreatic lymph nodes were determined after 4 and 6 weeks of treatment, as well as alterations in the expression of genes encoding β-cell autoantigens in the islets. The effect of MK626 was also assessed in two in vitro assays to determine proliferative and immunosuppressive effects. Results show that MK626 treatment reduces type 1 diabetes incidence and after 6 weeks of treatment reduces insulitis. No differences were observed in the percentage of T lymphocyte subsets from central and peripheral compartments between treated and control mice. MK626 increased the expression of CD26 in CD8+ T effector memory (TEM) from spleen and pancreatic lymph nodes and in CD8+ T cells from islet infiltration. CD8+TEM cells showed an increased proliferation rate and cytokine secretion in the presence of MK626. Moreover, the combination of CD8+ TEM cells and MK626 induces an immunosuppressive response. In conclusion, treatment with the DPPIV inhibitor MK626 prevents experimental type 1 diabetes in association to increase expression of CD26 in the CD8+ TEM lymphocyte subset. In vitro assays suggest an immunoregulatory role of CD8+ TEM cells that may be involved in the protection against autoimmunity to β pancreatic islets associated to DPPIV inhibitor treatment.

Elevated levels of Th17 cells in children with central obesity

BACKGROUND

It is believed that the recently discovered interleukin 17-producing Th17 cells play a role in the pathogenesis of chronic inflammation in the course of obesity and diabetes.

OBJECTIVES

The purpose of our study was to complete data on this subject in children.

METHODS

We assessed Th17 cell levels in the peripheral blood of children diagnosed with central obesity (n = 14) and compared the results with data obtained in patients with newly diagnosed (n = 11) and long-term type 1 diabetes mellitus (n = 18), and in a control group as well (n = 24).

RESULTS

(i) Children with central obesity were characterized by higher percentages of Th17 cells as compared to children from the control group; (ii) in the peripheral blood of patients with long-term type 1 diabetes the Th17 cell counts were higher compared to the control group; (iii) total plasma cholesterol concentration correlated positively with Th17/Treg cells ratio; and (iv) among patients with long-term diabetes, disease duration correlated positively with Th17 cell count and Th17/Th1 cell ratio.

CONCLUSION

The results of our study indicate that Th17 cells may be involved in chronic inflammation accompanying obesity and type 1 diabetes mellitus in children.

Combination immunotherapies for type 1 diabetes mellitus

Immunotherapies for type 1 diabetes mellitus (T1DM) have been the focus of intense basic and clinical research over the past few decades. Restoring β-cell function is the ultimate goal of intervention trials that target the immune system in T1DM. In an attempt to achieve this aim, different combination therapies have been proposed over the past few years that are based on treatments tackling the various mechanisms involved in the destruction of β cells. The results of clinical trials have not matched expectations based on the positive results from preclinical studies. The heterogeneity of T1DM might explain the negative results obtained, but previous trials have not addressed this issue. However, novel promising combination therapies are being developed, including those that couple immunomodulators with drugs that stimulate β-cell regeneration in order to restore normoglycaemia. This strategy is an encouraging one to pursue the goal of finding a cure for T1DM. This Review summarizes the available data about combination immunotherapies in T1DM, particularly addressing their clinical importance. The available data supporting the use of registered drugs, such as proton pump inhibitors and incretin-based agents, that have been shown to induce β-cell regeneration will also be discussed.

Antidiabetic therapy in post kidney transplantation diabetes mellitus

Post-transplantation diabetes mellitus (PTDM) is a common complication after kidney transplantation that affects up to 40% of kidney transplant recipients. By pathogenesis, PTDM is a diabetes form of its own, and may be characterised by a sudden, drug-induced deficiency in insulin secretion rather than worsening of insulin resistance over time. In the context of deteriorating allograft function leading to a re-occurrence of chronic kidney disease after transplantation, pharmacological interventions in PTDM patients deserve special attention. In the present review, we aim at presenting the current evidence regarding efficacy and safety of the modern antidiabetic armamentarium. Specifically, we focus on incretin-based therapies and insulin treatment, besides metformin and glitazones, and discuss their respective advantages and pitfalls. Although recent pilot trials are available in both prediabetes and PTDM, further studies are warranted to elucidate the ideal timing of various antidiabetics as well as its long-term impact on safety, glucose metabolism and cardiovascular outcomes in kidney transplant recipients.

Th17 cells in cancer: the ultimate identity crisis

T helper 17 (Th17) cells play a complex and controversial role in tumor immunity and have been found to exhibit a fluctuating identity within the context of cancer. The recent, expanding literature on these cells attests to their puzzling nature, either promoting or suppressing tumor growth depending on the malignancy and course of therapeutic intervention investigated. This review addresses several newly appreciated factors that may help delineate Th17 cells' immunological properties in the context of cancer. Several reports suggest that inflammatory signals induced in the tumor milieu regulate the functional fate and antitumor activity of Th17 cells. Recent findings also point to significant alterations in Th17 cells due to their interplay with regulatory T lymphocytes and cytotoxic CD8(+) T cells within the tumor microenvironment. Finally, an appreciation for the stem cell-like properties of Th17 cells that augment their persistence and activity emerges from recent reports. The impact of these factors on Th17 cells' antitumor efficacy and how these factors may be exploited to improve cancer therapies will be discussed.