Search

In hypoxic pulmonary hypertension (PH), pulmonary vascular remodeling is characterized by the emergence of activated adventitial fibroblasts, leading to medial smooth muscle hyperplasia. Previous studies have suggested that CD26/dipeptidyl peptidase-4 (DPP4) plays a crucial role in the pathobiological processes in lung diseases. However, its role in pulmonary fibroblasts in hypoxic PH remains unknown. Therefore, we aimed to clarify the mechanistic role of CD26/DPP4 in lung fibroblasts in hypoxic PH. Dpp4 knockout (Dpp4 KO) and wild-type (WT) mice were exposed to hypoxia for 4 weeks. The degree of PH severity and medial wall thickness was augmented in Dpp4 KO mice compared with that in WT mice, suggesting that CD26/DPP4 plays a suppressive role in the development of hypoxic PH. Transcriptome analysis of human lung fibroblasts cultured under hypoxic conditions revealed that TGFB2, TGFB3, and TGFA were all upregulated as differentially expressed genes after DPP4 knockdown with small interfering RNA treatment. These results suggest that CD26/DPP4 plays a suppressive role in TGFβ signal-regulated fibroblast activation under hypoxic conditions. Therefore, CD26/DPP4 may be a potential therapeutic target in patients with PH associated with chronic hypoxia. [ABSTRACT FROM AUTHOR]

Background: Research on diabetes treatment is advancing yearly, and it is estimated that 643 million adults worldwide will have diabetes by 2030. This is a comprehensive review of antidiabetic mechanisms in medicinal plants, aims to identify natural antidiabetic plants and provide details on their mechanisms of action, and rigorous testing techniques. Methodology: Information was gathered from offline and online sources to identify indigenous medicinal plants that lower blood glucose. Different databases were searched for ethnopharmacological literature using the following keywords: medicinal plants, diabetes, and India. Other sections about clinical trials, toxicological evaluations of certain plants, and preclinical trials have since been added. These sections were retrieved from Scopus using pertinent keywords. In this study, 117 species of medicinal plants from 55 families that are used to treat diabetes mellitus were listed. Conclusion: The variety of plants discussed in this review clearly demonstrated the importance of herbal plants in the treatment of diabetes. Result of the study shows Fabaceae, Rutaceae, and Combretaceae were the most prevalent plant families and species having antidiabetic properties among these plants. It also gives researchers information that they may use to develop future plans, like finding plants that may be effective in preventing diabetes and isolating bioactive molecules to help manage the disease. More research is necessary to completely comprehend these newly identified anti-diabetic drugs at the molecular, therapeutic, and physiological levels, nevertheless, in order to treat and manage diabetes mellitus globally

Context Dipeptidyl peptidase-4 (DPP4) is originally described as a surface protein in lymphocytes. Lymphocyte infiltration and subsequent destruction of thyroid tissue have been considered as the central pathological mechanism in Hashimoto thyroiditis (HT). Objective The present study aimed to investigate DPP4 expression in peripheral blood and thyroid tissue in HT patients, and explore the role of DPP4 in the pathophysiological process of HT. Methods This case-control study recruited 40 drug-naive HT patients and 81 control individuals. Peripheral blood and thyroid specimens were collected for assessing the expression and activity of DPP4. Moreover, single-cell RNA sequencing (scRNA-seq) analysis of 6 "para-tumor tissues" samples from scRNA-seq data set GSE184362 and in vitro cell experiments were also conducted. Results The HT patients had similar DPP4 serum concentration and activity as the controls. However, the expression and activity of DPP4 was significantly increased in the thyroid of the HT group than in the control group. The scRNA-seq analysis showed that DPP4 expression was significantly increased in the HT group, and mainly expressed in T cells. Further in vitro studies showed that inhibition of lymphocyte DPP4 activity with sitagliptin downregulated the production of inflammatory factors in co-cultured thyroid cells. Conclusion DPP4 expression was significantly increased in the thyroid of the HT group compared with the control group, and was mainly localized in the lymphocytes. Inhibition of lymphocyte DPP4 activity reduced the production of inflammatory factors in co-cultured thyroid cells. Therefore, inhibition of DPP4 may have a beneficial effect by alleviating inflammatory reactions in HT patients. [ABSTRACT FROM AUTHOR]

Exposure to chronic psychosocial stress is a risk factor for metabolic disorders. Because dipeptidyl peptidase‐4 (DPP4) and cysteinyl cathepsin K (CTSK) play important roles in human pathobiology, we investigated the role(s) of DPP4 in stress‐related adipocyte differentiation, with a focus on the glucagon‐like peptide‐1 (GLP‐1)/adiponectin‐CTSK axis in vivo and in vitro. Plasma and inguinal adipose tissue from non‐stress wild‐type (DPP4+/+), DPP4‐knockout (DPP4−/−) and CTSK‐knockout (CTSK−/−) mice, and stressed DPP4+/+, DPP4−/−, CTSK−/−, and DPP4+/+ mice underwent stress exposure plus GLP‐1 receptor agonist exenatide loading for 2 weeks and then were analyzed for stress‐related biological and/or morphological alterations. On day 14 under chronic stress, stress decreased the weights of adipose tissue and resulted in harmful changes in the plasma levels of DPP4, GLP‐1, CTSK, adiponectin, and tumor necrosis factor‐α proteins and the adipose tissue levels of CTSK, preadipocyte factor‐1, fatty acid binding protein‐4, CCAAT/enhancer binding protein‐α, GLP‐1 receptor, peroxisome proliferator‐activated receptor‐γ, perilipin2, secreted frizzled‐related protein‐4, Wnt5α, Wnt11 and β‐catenin proteins and/or mRNAs as well as macrophage infiltration in adipose tissue; these changes were rectified by DPP4 deletion. GLP‐1 receptor activation and CTSK deletion mimic the adipose benefits of DPP4 deficiency. In vitro, CTSK silencing and overexpression respectively prevented and facilitated stress serum and oxidative stress‐induced adipocyte differentiation accompanied with changes in the levels of pref‐1, C/EBP‐α, and PPAR‐γ in 3T3‐L1 cells. Thus, these findings indicated that increased DPP4 plays an essential role in stress‐related adipocyte differentiation, possibly through a negative regulation of GLP‐1/adiponectin‐CTSK axis activation in mice under chronic stress conditions. [ABSTRACT FROM AUTHOR]

Whey proteins are abundant in peptides that possess various biological activities. In order to enhance the biological properties of protein hydrolysates, it is essential to optimize the conditions of the hydrolysis process. In this study, optimal conditions for hydrolysis of whey protein concentrate (WPC) using filtered trypsin-like protease (FTLP) was determined in vitro. Further, the ability of optimized whey protein hydrolysates to inhibit dipeptidyl peptidase-4 (DiPP4) in vitro was examined. An optimum degree of hydrolysis (DH 42.9%) was obtained with an E:S ratio of 5:100 (w/w), 8.6 h, and a temperature of 40 °C. The factual DH under ideal conditions was 42.04%, indicating the efficiency of the selected model (p ≤ 0.05). Hydrolysates of WPC generated by FTLP, including both the unfractionated section and the fractions obtained via ultrafiltration using 10- and 5-kDa cut-off membranes, exhibited anti-diabetic characteristics. However, the fractions exhibited greater inhibitory effects against the DiPP4 enzyme, with IC50 values of 1.98, 1.19, and 0.9 mg/mL for the unfractionated, 10-kDa and 5-kDa fractions, respectively. Moreover, the results indicated that probiotic L. plantarum subsp. plantarum PTCC 1896 or its components may provide opportunities for future management of type-II diabetes by inhibiting DiPP4. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of cetagliptin (CAS number:2243737-33-7) in Chinese patients with type 2 diabetes mellitus (T2DM). A population PK/PD model was developed to quantify the PK and PD characteristics of cetagliptin in patients. Materials and methods: 32 Chinese adults with T2DM were enrolled in this study. The subjects were randomly assigned to receive either cetagliptin (50 mg or 100 mg), placebo, or sitagliptin (100 mg) once daily for 14 days. Blood samples were collected for PK and PD analysis. Effects on glucose, insulin, C-peptide, and glucagon were evaluated following an oral glucose tolerance test (OGTT) (day15). Effects on HbA1c and glycated albumin (GA), and safety assessments were also conducted. Meanwhile, a population PK/PD model was developed by a sequential two-step analysis approach using Phoenix. Results: Following multiple oral doses, cetagliptin was rapidly absorbed and the mean half-life were 34.9-41.9 h. Steady-state conditions were achieved after 1 week of daily dosing and the accumulation was modest. The intensity and duration of DPP-4 inhibition induced by 50 mg cetagliptin were comparable with those induced by sitagliptin, and 100 mg cetagliptin showed a much longer sustained DPP-4 inhibition (≥80%) than sitagliptin. Compared with placebo group, plasma active GLP-1 AUEC0-24h increased by 2.20- and 3.36-fold in the 50 mg and 100 mg cetagliptin groups. A decrease of plasma glucose and increase of insulin and C-peptide were observed following OGTT in cetagliptin groups. Meanwhile, a tendency of reduced GA was observed, whereas no decreasing trend was observed in HbA1c. All adverse events related to cetagliptin and sitagliptin were assessed as mild. A population PK/PD model was successfully established. The two-compartment model and Sigmoid-Emax model could fit the observed data well. Total bilirubin (TBIL) was a covariate of volume of peripheral compartment distribution (V2), and V2 increased with the increase of TBIL. Conclusions: Cetagliptin was well tolerated, inhibited plasma DPP-4 activity, increased plasma active GLP-1 levels, and exhibited a certain trend of glucoselowering effect in patients with T2DM. The established population PK/PD model adequately described the PK and PD characteristics of cetagliptin. [ABSTRACT FROM AUTHOR]

The probability of acute kidney injury (AKI) is higher in septic diabetic patients, which is associated with, among other factors, proximal tubular cell (PTC) injury induced by the hypoxic/hyperglycemic/inflammatory microenvironment that surrounds PTCs in these patients. Here, we exposed human PTCs (HK-2 cells) to 1% O2/25 mM glucose/inflammatory cytokines with the aim of studying the role of prostaglandin uptake transporter (PGT) and dipeptidyl peptidase-4 (DPP-4, a target of anti-hyperglycemic agents) as pharmacological targets to prevent AKI in septic diabetic patients. Our model reproduced two pathologically relevant mechanisms: (i) pro-inflammatory PTC activation, as demonstrated by the increased secretion of chemokines IL-8 and MCP-1 and the enhanced expression of DPP-4, intercellular leukocyte adhesion molecule-1 and cyclo-oxygenase-2 (COX-2), the latter resulting in a PGT-dependent increase in intracellular prostaglandin E2 (iPGE2); and (ii) epithelial monolayer injury and the consequent disturbance of paracellular permeability, which was related to cell detachment from collagen IV and the alteration of the cell cytoskeleton. Most of these changes were prevented by the antagonism of PGE2 receptors or the inhibition of COX-2, PGT or DPP-4, and further studies suggested that a COX-2/iPGE2/DPP-4 pathway mediates the pathogenic effects of the hypoxic/hyperglycemic/inflammatory conditions on PTCs. Therefore, inhibitors of PGT or DPP-4 ought to undergo testing as a novel therapeutic avenue to prevent proximal tubular damage in diabetic patients at risk of AKI. [ABSTRACT FROM AUTHOR]

Diabetes mellitus is a globally metabolic endocrine syndrome marked by a deficiency of insulin secretion (type‐1 DM) or glucose intolerance arising from insulin response impairment (type‐2 DM) leading to abnormal glucose metabolism. With an increasing interest in natural dietary components for diabetes management, the identification of novel agents witnessed major discoveries. Plant‐derived mucilage, pectin, and inulin are important non‐starch polysaccharides that exhibit effective antidiabetic properties often termed soluble dietary fiber (SDF). SDF affects sugar metabolism through multiple mechanisms affecting glucose absorption and diffusion, modulation of carbohydrate metabolizing enzymes (α‐amylase and α‐glucosidase), ameliorating β‐pancreatic cell dysfunction, and improving insulin release or sensitivity. Certain SDFs inhibit dipeptidyl peptidase‐4 and influence the expression levels of genes related to glucose metabolism. This review is designed to discuss holistically and critically the antidiabetic effects of major SDF and their underlying mechanisms of action. This review should aid drug discovery approaches in developing novel natural antidiabetic drugs from SDF. [ABSTRACT FROM AUTHOR]

Pulmonary hypertension (PH) with interstitial lung diseases (ILDs) often causes intractable conditions. CD26/Dipeptidyl peptidase-4 (DPP4) is expressed in lung constituent cells and may be related to the pathogenesis of various respiratory diseases. We aimed to clarify the functional roles of CD26/DPP4 in PH-ILD, paying particular attention to vascular smooth muscle cells (SMCs). Dpp4 knockout (Dpp4KO) and wild type (WT) mice were administered bleomycin (BLM) intraperitoneally to establish a PH-ILD model. The BLM-induced increase in the right ventricular systolic pressure and the right ventricular hypertrophy observed in WT mice were attenuated in Dpp4KO mice. The BLM-induced vascular muscularization in small pulmonary vessels in Dpp4KO mice was milder than that in WT mice. The viability of TGFβ-stimulated human pulmonary artery SMCs (hPASMCs) was lowered due to the DPP4 knockdown with small interfering RNA. According to the results of the transcriptome analysis, upregulated genes in hPASMCs with TGFβ treatment were related to pulmonary vascular SMC proliferation via the Notch, PI3K-Akt, and NFκB signaling pathways. Additionally, DPP4 knockdown in hPASMCs inhibited the pathways upregulated by TGFβ treatment. These results suggest that genetic deficiency of Dpp4 protects against BLM-induced PH-ILD by alleviating vascular remodeling, potentially through the exertion of an antiproliferative effect via inhibition of the TGFβ-related pathways in PASMCs. [ABSTRACT FROM AUTHOR]

Background: The objective of the study was to use docking and pharmacological research to explore phytochemicals as therapeutic candidates for the treatment of type 2 Diabetes Mellitus. Methods: The 100 plant compounds for the study were selected after a thorough review of the most recent literature using PubMed and Google Scholar. Three-dimensional structure in Structure-Data File Format of all phytochemicals was downloaded and collected from the PubChem platform. In parallel, the three-dimensional structure of the target protein dipeptidyl peptidase-4 in Protein Data Bank (PDB) format was obtained from the website of the Research Collaboratory for Structural Bioinformatics-PDB. AutoDock Vina software was used for the docking purpose. SwissADME and the admetSAR web server were used to further examine the top docked compounds for the pharmacological investigation. Results: Out of 100 phytochemicals, only 15 have shown better or comparable binding affinity above the benchmark medication, sitagliptin (−7.9 kcal/mol). All of these compounds were assessed to determine their viability as potential drugs by predicting their Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties. Two of these phytochemicals have proven their potential as medication candidates by passing the ADMET requirements. Conclusions: In silico studies help explore and find drug candidates among the enormous pool of phytochemicals and narrow down the screening process, saving time and money on experiments. In vitro and in vivo testing can be used in the future to further validate drug candidature. [ABSTRACT FROM AUTHOR]

Background: The objective of the study was to use docking and pharmacological research to explore phytochemicals as therapeutic candidates for the treatment of type 2 Diabetes Mellitus. Methods: The 100 plant compounds for the study were selected after a thorough review of the most recent literature using PubMed and Google Scholar. Three-dimensional structure in Structure-Data File Format of all phytochemicals was downloaded and collected from the PubChem platform. In parallel, the three-dimensional structure of the target protein dipeptidyl peptidase-4 in Protein Data Bank (PDB) format was obtained from the website of the Research Collaboratory for Structural Bioinformatics-PDB. AutoDock Vina software was used for the docking purpose. SwissADME and the admetSAR web server were used to further examine the top docked compounds for the pharmacological investigation. Results: Out of 100 phytochemicals, only 15 have shown better or comparable binding affinity above the benchmark medication, sitagliptin (−7.9 kcal/mol). All of these compounds were assessed to determine their viability as potential drugs by predicting their Absorption, Distribution, Metabolism, Excretion, and Toxicity (ADMET) properties. Two of these phytochemicals have proven their potential as medication candidates by passing the ADMET requirements. Conclusions: In silico studies help explore and find drug candidates among the enormous pool of phytochemicals and narrow down the screening process, saving time and money on experiments. In vitro and in vivo testing can be used in the future to further validate drug candidature.

Diabetes is highly linked to the occurrence of Alzheimer disease (AD), which is characterized by beta amyloid peptide (Aβ) and hyperphosphorylation of tau (p-tau), and neuron damage particularly in hippocampus. Type 2 diabetes (T2D) is featured by insulin resistance, and phosphorylation of Ser307-IRS-1 is regarded as a resistance marker. Inhibitors of dipeptidyl peptidase-4 (DPP-4) are effective tools for treating T2D. Previously, we reported subfractions of Abelmoschus esculentus (AE, okra) (F1 rich in quercetin glycosides; F2 composed of polysaccharide) attenuated DPP-4 and its downstream signals of insulin resistance, thus preventing Aβ-induced neuron damage. Since autophagy could be protective, we now explore if AE works to modulate neuron autophagy by regulating DPP-4 and insulin resistance and, thus, improves the hippocampal function and behavior. We demonstrated that AE subfractions attenuate Aβ-induced insulin resistance and the expression of p-tau and normalize the autophagy and survival of hippocampal neurons. The action of AE may be attributed to the downregulation of DPP-4, which plays a critical role in mediating insulin resistance and hinders neuron autophagy. The in vivo findings reveal that the hippocampal insulin resistance appears to link with loss of memory, reduction of curiosity, and depression, whereas treatment with AE significantly improves the insulin sensitivity and hippocampal function. Noteworthy, even at only 5 μg/mL, F2 seems to exhibit a meaningful effect. In conclusion, we suggest that AE attenuates insulin resistance and recovers neuron autophagy which are regulated by DPP-4, thus preventing the damage to the hippocampus, improving recognition and emotion. AE may be an effective adjuvant or supplement to prevent insulin resistance-associated pathogenesis of AD if these results can be confirmed in human clinical trials. [ABSTRACT FROM AUTHOR]

In this study, the synthesis of three pyrazoline derivatives and the evaluation of their inhibitory effects on dipeptidyl peptidase (DPP-4) were aimed.

Abstract Background Limited joint mobility (LJM), previously known as cheiroarthropathy, refers to the presence of reduced extension at the finger joints in people with diabetes and may be associated with scleroderma-like syndromes such as diabetic sclerodactyly. While scleroderma-like syndromes and LJM have been observed in patients with long-term diabetes and associated complications, the coexistence of diabetes with Juvenile systemic sclerosis (jSSc) is rarely described. Case presentation We describe the case of a 14-year-old boy with long-lasting type 1 diabetes (T1D) and suspected LJM associated with Raynaud phenomenon, sclerodactyly and tapering of the fingertips. A comprehensive work-up showed positive autoantibodies (ANA, anti-Ro-52, anti-Mi-2b), abnormal nailfold capillaroscopy with a scleroderma pattern, interstitial lung disease and cardiac involvement. The overall clinical picture was consistent with the diagnosis of jSSc. Conclusions LJM can be the initial sign of underlying systemic sclerosis. Nailfold capillaroscopy may help differentiate jSSc from classical LJM in pediatric patients with T1D and finger contractures or skin induration of no clear origin. This case report provides a starting point for a novel hypothesis regarding the pathogenesis of jSSc. The association between T1D and jSSc may be more than a coincidence and could suggest a relationship between glucose metabolism, fibrosis and microangiopathy.

Uterine fibroid or leiomyoma is the most common benign uterus tumor. The tumor is primarily composed of smooth muscle (fibroid) cells, myofibroblast, and a significant amount of extracellular matrix components. It mainly affects women of reproductive age. They are uncommon before menarche and usually disappear after menopause. The fibroids have excessive extracellular matrix components secreted by activated fibroblast cells (myofibroblast). Myofibroblast has the characteristics of fibroblast and smooth muscle cells. These cells possess contractile capability due to the expression of contractile proteins which are normally found only in muscle tissues. The rigid nature of the tumor is responsible for many side effects associated with uterine fibroids. The current drug treatment strategies are primarily hormone-driven and not anti-fibrotic. This paper emphasizes the fibrotic background of uterine fibroids and the mechanisms behind the deposition of excessive extracellular matrix components. The transforming growth factor-β, hippo, and focal adhesion kinase-mediated signaling pathways activate the fibroblast cells and deposit excessive extracellular matrix materials. We also exemplify how dipeptidyl peptidase-4 and fibroblast activation protein inhibitors could be beneficial in reducing the fibrotic process in leiomyoma. Dipeptidyl peptidase-4 and fibroblast activation protein inhibitors prevent the fibrotic process in organs such as the kidneys, lungs, liver, and heart. These inhibitors are proven to inhibit the signaling pathways mentioned above at various stages of their activation. Based on literature evidence, we constructed a narrative review on the mechanisms that support the beneficial effects of dipeptidyl peptidase-4 and fibroblast activation protein inhibitors for treating uterine fibroids. [ABSTRACT FROM AUTHOR]

Type II diabetes is an endemic disease and is responsible for approximately 90% to 95% of diabetes cases. The pathophysiological distortions are majorly β-cell dysfunction, insulin resistance, and long-term inflammation, which all progressively unsettle the control of blood glucose levels and trigger microvascular and macrovascular complications. The diverse pathological disruptions which patients with type II diabetes mellitus exhibit precipitate the opinion that different antidiabetic agents, administered in combination, might be required to curb this menace and maintain normal blood glucose. To this end, natural compounds were screened to identify small molecular weight compounds with inhibitory effects on protein tyrosine phosphatase 1B (PTP1B), dipeptidyl-peptidase-4 (DPP-4), and α-amylase. From the result, the top 5 anthocyanins with the highest binding affinity are reported herein. Further ADMET profiling showed moderate pharmacokinetic profiles for these compounds as well as insignificant toxicity. Cyanidin 3-(p-coumaroyl)-diglucoside-5-glucoside (−15.272 kcal/mol), cyanidin 3-O-(6ʺ-malonyl-3ʺ-glucosyl-glucoside) (−9.691 kcal/mol), and delphinidin 3,5-O-diglucoside (−12.36 kcal/mol) had the highest binding affinities to PTP1B, DPP-4, and α-amylase, respectively, and can be used in combination to control glucose fluctuations. However, validations must be carried out through further in vitro and in vivo tests. [ABSTRACT FROM AUTHOR]

T cells play a crucial role in atherosclerosis, with its infiltration preceding the formation of atheroma. However, how T‐cell infiltration is regulated in atherosclerosis remains largely unknown. Here, this work demonstrates that dipeptidyl peptidase‐4 (DPP4) is a novel regulator of T‐cell motility in atherosclerosis. Single‐cell ribonucleic acid (RNA) sequencing and flow cytometry show that CD4+ T cells in atherosclerotic patients display a marked increase of DPP4. Lack of DPP4 in hematopoietic cells or T cells reduces T‐cell infiltration and atherosclerotic plaque volume in atherosclerosis mouse models. Mechanistically, DPP4 deficiency reduces T‐cell motility by suppressing the expression of microtubule associated protein midline‐1 (Mid1) in T cells. Deletion of either DPP4 or Mid1 inhibits chemokine‐induced shape change and motility, while restitution of Mid1 in Dpp4−/− T cell largely restores its migratory ability. Thus, DPP4/Mid1, as a novel regulator of T‐cell motility, may be a potential inflammatory target in atherosclerosis. [ABSTRACT FROM AUTHOR]

The pathogenesis of pulmonary fibrosis involves complex interplay between cell types and signaling pathways. Recurrent alveolar epithelial injury can occur during pulmonary inflammation, causing dysregulation of epithelial repair. Dysregulated repair interacts with mesenchymal, inflammatory, and endothelial cells to trigger fibroblast‐to‐myofibroblast activation. CD26/dipeptidyl peptidase‐4 (DPP4) is a type II membrane protein mediating pleiotropic effect. However, the mechanistic role of CD26/DPP4 in pulmonary fibrosis remains unclear. In this study, we aimed to characterize Dpp4 deficiency in a mouse bleomycin (BLM)‐induced pulmonary fibrosis model and in cell culture systems of human lung fibroblasts (HLFs). Dpp4 knockout (Dpp4 KO) mouse lungs exhibited lower Ashcroft scale indices, collagen content, and numbers of fibroblasts and myofibroblasts compared with those in C57BL/6 wild‐type (WT) mice. Upregulation of Tgfb1 and Tgfb2 mRNA levels in the lungs after BLM treatment was lower in Dpp4 KO mice compared with those in WT mice. Although TGF‐β‐driven endothelial‐to‐mesenchymal transition (EndMT) has been implicated as one of the mechanisms of pulmonary fibrosis, a number of partial EndMT cells in lungs did not differ between Dpp4 KO mice and WT mice. The proliferation capacity and mRNA levels of COL1A1, a collagen deposition‐related gene, in cultured HLFs were suppressed in DPP4 small interfering RNA‐treated cells. This study indicates that the genetic deficiency of DPP4 has protective effects against BLM‐induced pulmonary fibrosis, partly through the reduction in TGF‐β expression and inhibition of fibroblast activation in the lung. Our study suggests that CD26/DPP4 inhibition is a potential therapeutic strategy for pulmonary fibrosis. [ABSTRACT FROM AUTHOR]

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

The potential of plant bioactives for the prevention and therapy of diabetes is increasingly being recognized. In the present study we investigated the antidiabetic properties of an aqueous Bistorta officinalis Delarbre extract (BODE) by employing both in-vitro assays and in-vivo models. Multiple targets in glucose homeostasis which are involved in the regulation of the blood glucose level were affected by BODE in-vitro. The extract exhibited inhibitory activities towards the intestinal carbohydrate-hydrolysing enzymes a-amylase and a-glucosidase with IC50 values of 81.5 µg/mL and 8.4 µg/mL, respectively. Furthermore, moderate reduction of the dipeptidyl peptidase-4 (DPP4) enzyme activity was evident when tested in the presence of 1.0 mg/mL BODE. A significant inhibition of the intestinal glucose transporter sodiumdependent glucose transporter 1 (SGLT1) in response to 1.0 mg/mL BODE was shown for Caco-2 cells mounted in Ussing chambers. High performance liquid chromatography-mass spectrometry analyses of the BODE revealed several plant bioactives including gallotannins, catechins and chlorogenic acid. Although our in-vitro data were promising, BODE-supplementation in the model organism Drosophila melanogaster lacked to confirm the antidiabetic effect of the extract in-vivo. Moreover, BODE failed to reduce blood glucose levels in chicken embryos (in-ovo). Hence, BODE is probably not a suitable candidate for developing a pharmaceutical against diabetes mellitus. [ABSTRACT FROM AUTHOR]

Coronavirus disease 2019 (Covid-19) is caused by severe acute respiratory syndrome type 2 (SARS-CoV-2). Covid-19 is characterized by hyperinflammation, oxidative stress, and multi-organ injury (MOI) such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). Covid-19 is mainly presented with respiratory manifestations; however, extra-pulmonary manifestations may also occur. Extra-pulmonary manifestations of Covid-19 are numerous including: neurological, cardiovascular, renal, endocrine, and hematological complications. Notably, a cluster of differentiation 26 (CD26) or dipeptidyl peptidase-4 (DPP-4) emerged as a new receptor for entry of SARS-CoV-2. Therefore, DPP-4 inhibitors like sitagliptin could be effective in treating Covid-19. Hence, we aimed in the present critical review to assess the potential role of sitagliptin in Covid-19. DPP-4 inhibitors are effective against the increased severity of SARS-CoV-2 infections. Moreover, DPP-4 inhibitors inhibit the interaction between DPP-4 and scaffolding proteins which are essential for endosome formation and replication of SARS-CoV-2. Therefore, sitagliptin through attenuation of the inflammatory signaling pathway and augmentation of stromal-derived factor-1 (SDF-1) may decrease the pathogenesis of SARS-CoV-2 infection and could be a possible therapeutic modality in treating Covid-19 patients. In conclusion, the DPP-4 receptor is regarded as a potential receptor for the binding and entry of SARS-CoV-2. Inhibition of these receptors by the DPP-4 inhibitor, sitagliptin, can reduce the pathogenesis of the infection caused by SARS-CoV-2 and their associated activation of the inflammatory signaling pathways. [ABSTRACT FROM AUTHOR]

Inhibition of dipeptidyl peptidase-4 (DPP4) activity has emerged as a promising therapeutic approach for the treatment of type 2 diabetes mellitus (T2DM). Bioinformatics-driven approaches have emerged as crucial tools in drug discovery. Molecular docking and molecular dynamics (MD) simulations are effective tools in drug discovery, as they reduce the time and cost associated with experimental screening. In this study, we employed structure-assisted in-silico methods, including molecular docking and MD simulations, to identify SRT2183, a small molecule that may potentially inhibit the activity of DPP4 enzyme. The interaction between the small molecule "SRT2183" and DPP4 exhibited a binding affinity of -9.9 Kcal/Mol, leading to the formation of hydrogen bonds with the amino acid residues MET348, SER376, and THR351 of DPP4. The MD simulations over a period of 100 ns indicated stable protein-ligand interactions, with no significant conformational rearrangements observed within the simulated timeframe. In conclusion, our results suggest that the small molecule SRT2183 may have the potential to inhibit the DPP4 enzyme and pave the way for the therapeutics of T2DM.Communicated by Ramaswamy H. Sarma.

Alzheimer's disease (AD) is the most common disease associated with cognitive dysfunction, which is closely associated with type 2 diabetes mellitus (T2DM) in clinical manifestations, pathological changes and prevention. Inhibition of dipeptidyl peptidase 4 (DPP-4) can lower blood glucose levels by stimulating insulin secretion. Besides, it can affect cognitive function through the neuroprotective effect of DPP-4 substrates, such as glucose-dependent insulin peptide and glucagon-like peptide-1, the proteolytic effect on amyloid-β and the protective effect on neuronal structure. This review discusses the relationship between cognitive impairment in T2DM and in AD, summarizes the effect of DPP-4 inhibitor (DPP-4i) on improving cognitive impairment in these two diseases based on the current studies. Given the lack of clinical randomized trials that evaluate the effect of DPP-4i on AD, this review is expected to provide preclinical evidence for DPP-4i as a potential therapy for the treatment and prevention of AD., Competing Interests: Declaration of conflicting interestsThe authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The thieno[2,3-d]pyrimidine fragment is in the structure of many drug-like candidate derivatives with a wide range of biological activities. However, very few dipeptidyl peptidase-4 (DPP-4) inhibitors with this building block are currently known. Here, the selection of a novel DPP-4 inhibitor based on the thienopyrimidine scaffold is reported. In the performed study, ethyl 4-amino-5-methyl-2-(3-(trifluoromethyl)phenyl)thieno[2,3-d]pyrimidine-6-carboxylate (compound 22) demonstrated DPP-4 inhibitory potential about twice higher than that of the reference inhibitor diprotin A. The manner of inhibition is noncompetitive, a rare type among DPP-4 inhibitors. The molecular docking highlighted the importance of Ser349, Asn377, Glu378, Phe396, and Asp588 in forming the inhibitor/DPP-4 complex. Compound 22 might be useful as a source of ideas contributing to the design and further changes and optimizations of thieno[2,3-d]pyrimidine-based DPP-4 inhibitors., (© 2024 Wiley‐VHCA AG, Zurich, Switzerland.)

Abstract Background Abnormal metabolic features have been previously described in adolescent idiopathic scoliosis (AIS) patients. As an important regulator involved in energy metabolism, DPP-4 activity was reported to be remarkably decreased in osteoblasts of AIS patients. To date, there was still a lack of knowledge concerning the role of DPP-4 in the myogenesis of AIS. Methods Circulation DPP-4 level was assessed in the serum of 80 AIS girls and 50 healthy controls by ELISA. Myoblasts were purified from muscle specimens of AIS patients and LDH controls, and then treated with metabolic effectors including glucose and insulin. CCK-8 assay was used to assess the cell viability and myotube fusion index was calculated to evaluate myogenesis ability. Gene expressions of downstream signals of DPP-4 were evaluated by RT-qPCR and Western blot respectively. Results AIS girls had remarkably down-expressed DPP-4 in both serum level (0.76 fold) and tissue (0.68 fold) level. Treatment with metabolic effectors led to significantly increased DPP-4 expression in the control cells, while there was no increase of DPP-4 in AIS cells. CCK-8 assay showed that the proliferation rate of control cells was significantly increased after being treated. Remarkably higher fusion index was also observed in the treated control cells. By contrast, the fusion index and cell proliferation rate were comparable between the treated and the untreated AIS cells. Conclusions Our study suggested a potential role of DPP-4 in abnormal metabolic condition of AIS patients. Compared with control cells, AIS myoblasts presented obviously impaired sensitivity to the treatment of glucose and insulin. Aberrant DPP-4 expression could lead to impaired insulin sensitivity in myoblasts and further influence the cell viability during myogenesis. The molecular mechanism connecting DPP-4 and insulin-related signaling in AIS is worthy of further investigation.

Background: Evidence showed that abnormal alteration of adipokines level may perform a key role in polycystic ovary syndrome (PCOS) pathogenesis. Dipeptidyl peptidase-4 (DPP4) and progranulin (PGRN) are two novel adipokines related to insulin resistance (IR). Thus, we aimed to determine the serum DPP4 activity and PGRN level in PCOS patients with and without IR, and non-PCOS women. Methods: Ninety women were recruited in the present study including 60 PCOS patients (divided into two groups of 30 IR and 30 non-IR) and 30 non-PCOS women. Serum levels of insulin, fasting blood glucose, PGRN, and DPP4 activity were measured, and IR indices were calculated. Results: DPP4 activity was significantly higher in PCOS-IR and PCOS-NIR patients than non-PCOS women (p

Introduction: The studies in animal models of cirrhosis suggest that dipeptidyl peptidase type 4 (DPP-4) enzymes play a crucial role in disease pathogenesis. In this clinical observational study, activity of DPP-4 and related gene expression were analysed in chronic liver disease patients. Objectives: To understand the DPP-4 enzyme activity variation in the common types of chronic liver disease by assessing plasma and peripheral blood mononuclear cell (PBMC) DPP-4 activity and comparing with healthy controls and to explore DPP-4 gene expression in PBMC. Methods: We recruited 130 study subjects in four cohorts—46 nonalcoholic fatty liver disease (NAFLD), 23 non-alcoholic cirrhosis (NAC) excluding viral aetiology, 21 alcoholic liver disease (ALC), and 40 control subjects. Blood samples were analysed for relevant biochemical parameters and plasma DPP-4 activity. PBMC fraction was used for the DPP-4 activity assay and gene expression analysis. Results: We found that lower plasma DPP-4 activity among patient cohorts but this was not statistically significant. The PBMC DPP-4 activity was significantly lower in NAFLD cohort. In the same cohort, DPP-4 gene expression in PBMC fraction was significantly increased (P < 0.05). There was significant correlation between plasma DPP-4 activity and liver injury marker alanine aminotransferase (ALT) among NAFLD (rho = 0.459, P < 0.01), NAC (rho = 0.475, P < 0.05), and ALC (rho = –0.572, P < 0.01) patients. Plasma DPP-4 activity modestly predicted ALT plasma level (beta coefficient = 0.489, P < 0.01). Conclusions: The PBMC DPP-4 activity and DPP-4 gene expression gets significantly altered in NAFLD patients. Plasma DPP-4 activity also shows correlation with ALT levels in CLD patients. The role of DPP-4 in disease pathology in NAFLD and other forms of CLD needs to be explored.

Inhibition of dipeptidyl peptidase-4 (DPP-4) is an effective way to control blood glucose in diabetic patients. Tenebrio (T.) molitor is an edible insect containing abundant protein. T. molitor protein-derived peptides can suppress the DPP-4 activity. However, the amino acid sequence and binding mechanism of these DPP-4 inhibitory peptides remain unclear. This study used the flavourzyme for T. molitor protein hydrolysis, identified the released peptides with DPP-4 inhibitory effect, and investigated the binding interactions of these peptides with DPP-4. The results showed that flavourzyme efficiently hydrolyzed the T. molitor protein, as demonstrated by the high degree of hydrolysis, disappearance of protein bands in SDS-PAGE, and changes to protein structure. The 4-h flavourzyme hydrolysates showed a good inhibitory effect on DPP-4 (IC50 value of 1.64 mg/mL). The fragment of 1000–3000 Da accounted for 10.39% of the total peptides, but showed the strongest inhibitory effect on DPP-4. The peptides LPDQWDWR and APPDGGFWEWGD were identified from this fraction, and their IC50 values against DPP-4 were 0.15 and 1.03 mg/mL, respectively. Molecular docking showed that these two peptides interacted with the DPP-4 active site via hydrogen bonding, hydrophobic interactions, salt bridge formation, π-cation interactions, and π-π stacking. Our findings indicated that T. molitor protein-derived peptides could be used as natural DPP-4 inhibitors. [ABSTRACT FROM AUTHOR]

Purpose: Biologics are structurally heterogeneous and can undergo biotransformation in the body. Etanercept (ETN) is a fusion protein composed of a soluble tumor necrosis factor (TNF) receptor and the Fc portion of human immunoglobulin G1. The N-terminus of ETN has a putative sequence cleaved by dipeptidyl peptidase-4 (DPP-4). The purpose of this study was to investigate the biotransformation of ETN in humans and mice and evaluate its effects on functional properties. Methods: An analytical method using liquid chromatography-mass spectrometry (LC–MS/MS) was established. The N-terminal heterogeneity of ETN was assessed in the serum of patients with rheumatoid arthritis or mice receiving ETN. The in vitro N-terminal truncation was explored using recombinant DPP-4. The binding affinity to TNF-α or TNF-β was investigated using an in-house enzyme-linked immunosorbent assay. Results: In the formulations, about 90% of ETN had an intact N-terminus, while the N-terminal truncated form was most abundant in the serum of the patients with rheumatoid arthritis and mice. Recombinant human DPP-4 cleaved two amino acids from the N-terminus of ETN in vitro. Sitagliptin, a DPP-4 inhibitor, inhibited N-terminal truncation both in vivo and in vitro. However, N-terminal truncation did not affect the binding ability to TNF-α or TNF-β and the pharmacokinetics of ETN. ETN biosimilars exhibited similar characteristics to the reference product in vivo and in vitro. Conclusions: ETN undergoes N-terminal truncation in the body, and DPP-4 cleaves exogenous ETN via N-terminal proteolysis. The application of an MS-based assay will detect novel biotransformation of therapeutic proteins. [ABSTRACT FROM AUTHOR]

Background: Limited joint mobility (LJM), previously known as cheiroarthropathy, refers to the presence of reduced extension at the finger joints in people with diabetes and may be associated with scleroderma-like syndromes such as diabetic sclerodactyly. While scleroderma-like syndromes and LJM have been observed in patients with long-term diabetes and associated complications, the coexistence of diabetes with Juvenile systemic sclerosis (jSSc) is rarely described. Case presentation: We describe the case of a 14-year-old boy with long-lasting type 1 diabetes (T1D) and suspected LJM associated with Raynaud phenomenon, sclerodactyly and tapering of the fingertips. A comprehensive work-up showed positive autoantibodies (ANA, anti-Ro-52, anti-Mi-2b), abnormal nailfold capillaroscopy with a scleroderma pattern, interstitial lung disease and cardiac involvement. The overall clinical picture was consistent with the diagnosis of jSSc. Conclusions: LJM can be the initial sign of underlying systemic sclerosis. Nailfold capillaroscopy may help differentiate jSSc from classical LJM in pediatric patients with T1D and finger contractures or skin induration of no clear origin. This case report provides a starting point for a novel hypothesis regarding the pathogenesis of jSSc. The association between T1D and jSSc may be more than a coincidence and could suggest a relationship between glucose metabolism, fibrosis and microangiopathy. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Diabetic kidney disease is one of the most frequent complications in patients with diabetes mellitus and affects morbidity and mortality. The recent therapies include oral hypoglycemic drugs that, in addition to optimizing glycemic control and reducing the risk of hypoglycemia, may affect the development and progression of diabetic kidney disease; these novel therapies include inhibitors of the enzyme dipeptidyl peptidase 4 (DPP-4), a group of oral hypoglycemic therapeutic agents that act at the level of the incretin system. DPP-4 inhibitors show additional pleiotropic effects in in vitro models, reducing inflammation, fibrosis, and oxidative damage, further suggesting potential kidney protective effects. Although existing trials suggest a possible benefit in the progression of diabetic kidney disease, further studies are needed to demonstrate kidney-specific benefits of DPP-4 inhibitors.

Abstract Dipeptidyl peptidase‐4 (DPP‐4), namely CD26, is expressed on the surface of immune cells, suggesting that inhibition of DPP‐4 might affect the immune system. The current multicenter observational case–control study was carried out to investigate the effects of DPP‐4 inhibitor (DPP‐4i) administration on Graves' disease (GD) activity. This study comprised patients with GD and type 2 diabetes, who were administered an oral hypoglycemic agent including DPP‐4i. Exacerbation of GD was defined as an increase of antithyroid drug dose by 6 months after oral hypoglycemic agent administration. A total of 80 patients were enrolled and divided into an exacerbation group or a non‐exacerbation group. The frequency of DPP‐4i administration was significantly higher in the exacerbation group (88%) than that in the non‐exacerbation group (31%). In multivariate logistic regression analysis, there was a significant association between DPP‐4i administration and GD exacerbation (odds ratio 7.39). The current study suggests that DPP‐4i administration is associated with GD exacerbation.

Type 2 diabetes mellitus (T2DM) is a growing global public health issue, and dipeptidyl peptidase-4 (DPP-4) is a potential therapeutic target in T2DM. Several synthetic anti-DPP-4 medications can be used to treat T2DM. However, because of adverse effects, there is an unmet demand for the development of safe and effective medications. Natural medicines are receiving greater interest due to the inherent safety of natural compounds. Glycyrrhiza uralensis (licorice) is widely consumed and used as medicine. In this study, we investigated the abilities of a crude water extract (CWE) of G. uralensis and two of its constituents (licochalcone A (LicA) and licochalcone B (LicB)) to inhibit the enzymatic activity of DPP-4 in silico and in vitro. In silico studies showed that LicA and LicB bind tightly to the catalytic site of DPP-4 and have 11 amino acid residue interactions in common with the control inhibitor sitagliptin. Protein-protein interactions studies of LicA-DPP4 and LicB-DPP4 complexes with GLP1 and GIP reduced the DPP-4 to GLP1 and GIP interactions, indicated that these constituents might reduce the degradations of GLP1 and GIP. In addition, molecular dynamics simulations revealed that LicA and LicB stably bound to DPP-4 enzyme. Furthermore, DPP-4 enzyme assay showed the CWE of G. uralensis, LicA, and LicB concentration-dependently inhibited DPP-4; LicA and LicB had an estimated IC50 values of 347.93 and 797.84 μM, respectively. LicA and LicB inhibited DPP-4 at high concentrations, suggesting that these compounds could be used as functional food ingredients to manage T2DM.

Abstract Background Nesfatin-1, a novel adipokine and dipeptidyl peptidase-4 (DPP4), a mam malian serine protease, are potent factors of atherosclerosis. In the present cross-sectional study, we investigated whether the plasma nesfatin-1 and DPP4 is associated with the prevalence and severity of coronary artery disease (CAD) with and without diabetes mellitus (DM). Methods We consecutively enrolled a total of 240 patients with significant CAD (previous revascularization or angiographically-proven coronary artery stenosis > 50%) presented with either unstable angina (UA, N = 76) or stable chronic CAD (SCAD, N = 165). 85 patients with at least 2 classical cardiovascular risk factors but without significant CAD served as controls. The severity of CAD was assessed using coronary angiography by the Gensini score. Clinical parameters, glycemic and lipid profile, high-sensitivity CRP (hsCRP), nesfatin-1 and DPP4 levels were assayed. Results No differences were found for age, sex, hypertension and diabetes distribution between groups. Low nesfatin-1 levels were found in both CAD groups (UA & SCAD) with respect to controls. The difference between UA and SCAD groups was marginally non-significant. There was a significant increase of DPP4 along UA to SCAD and control groups. Differences between groups remained unchanged in non-diabetic participants. Nesfatin-1 significantly correlated to hsCRP (r = − 0.287, p = 0.036), HOMA-IR (r = − 0.587, p = 0.007) and hyperlipidemia (r = − 0.331, p = 0.034). DPP4 was significantly associated with hs-CRP (r = 0.353 p

Background: The age-related increase in blood pressure in spontaneously hypertensive rats (SHRs) is associated to cardiac hypertrophy, heart failure, and renal injury. Here, we investigated for the first time the urinary enzymatic activities of glutamil aminopeptidase (GluAp), alanyl aminopeptidase (AlaAp), dipeptidyl peptidase-4 (DPP4), and Klotho urinary levels, proteins that are strongly expressed in the kidney, as early biomarkers of renal injury in SHRs. Methods: Male SHR and Wistar Kyoto (WKY) rats were studied from 2 to 8 months old. Systolic blood pressure (SBP), the heart rate (HR), metabolic variables, and urinary markers were measured monthly. At the end of the study, a histopathological evaluation of the kidney was performed. Results: Kidneys of SHR did not develop signs of relevant histopathological changes, but showed increased glomerular area and cellularity. Plasma creatinine was decreased, and creatinine clearance was augmented in SHR at the end of the study. Urinary excretion of Klotho was higher in SHR at 5 and 8 months old, whereas plasma Klotho levels were similar to WKY. GluAp, AlaAp, and DPP4 urinary activities were increased in SHR throughout the time-course study. A positive correlation between glomerular area and cellularity with creatinine clearance was observed. Urinary GluAp, AlaAp, DPP4, and Klotho showed positive correlations with SBP. Conclusions: GluAp, AlaAp, DPP4, and Klotho in the urine are useful tools for the evaluation of renal damage at early stages, before the whole histopathological and biochemical manifestations of renal disease are established. Moreover, these observations may represent a novel and noninvasive diagnostic approach to assess the evolution of kidney function in hypertension and other chronic diseases.

Abstract The global high prevalence of diabetes mellitus has resulted into the development of several oral hypoglycemic agents. However, these drugs have limited efficacy and harmful side effects, which call for the search for alternatives from natural sources. The inhibition of dipeptidyl peptidase‐4 (DPP‐4) activity increases the level of glucagon‐like peptide‐1 and glucose‐dependent insulinotropic polypeptide, which in turn reduces hyperglycemia by activating insulin secretion and inhibiting glucagon secretion. Some studies have reported the in vitro DPP‐4 inhibitory potential of functional foods, but there is no repository of information on these reports. This article is an attempt to present in concise form, reports of functional foods with DPP‐4 inhibitory potentials in vitro. This will guide the use of these foods as well as in antidiabetic drug development.

The prediction of possible lead compounds from already-known drugs that may present DPP-4 inhibition activity imply a advantage in the drug development in terms of time and cost to find alternative medicines for the treatment of Type 2 Diabetes Mellitus (T2DM). The inhibition of dipeptidyl peptidase-4 (DPP-4) has been one of the most explored strategies to develop potential drugs against this condition. A diverse dataset of molecules with known experimental inhibitory activity against DPP-4 was constructed and used to develop predictive models using different machine-learning algorithms. Model M36 is the most promising one based on the internal and external performance showing values of Q2 CV = 0.813, and Q2 EXT = 0.803. The applicability domain evaluation and Tropsha's analysis were conducted to validate M36, indicating its robustness and accuracy in predicting pIC 50 values for organic molecules within the established domain. The physicochemical properties of the ligands, including electronegativity, polarizability, and van der Waals volume were relevant to predict the inhibition process. The model was then employed in the virtual screening of potential DPP4 inhibitors, finding 448 compounds from the DrugBank and 9 from DiaNat with potential inhibitory activity. Molecular docking and molecular dynamics simulations were used to get insight into the ligand-protein interaction. From the screening and the favorable molecular dynamic results, several compounds including Skimmin (pIC 50 = 3.54, Binding energy = −8.86 kcal/mol), bergenin (pIC 50 = 2.69, Binding energy = −13.90 kcal/mol), and DB07272 (pIC 50 = 3.97, Binding energy = −25.28 kcal/mol) seem to be promising hits to be tested and optimized in the treatment of T2DM. This results imply a important reduction in cost and time on the application of this drugs because all the information about the its metabolism is already available. [Display omitted] • Type 2 Diabetes Mellitus (T2DM) is a persistent condition in the world. • dipeptidyl peptidase-4 inhibition plays a pivotal role in T2DM treatment. • Machine learning algorithms are useful for model construction. • Molecular dynamic simulations are of interest in drug design. • New drug candidates are suggested for the T2DM treatment. [ABSTRACT FROM AUTHOR]

Type 2 diabetes (T2D) is an expanding global health problem, resulting from defects in insulin secretion and/or insulin resistance. In the past few years, both protein tyrosine phosphatase 1B (PTP1B) and dipeptidyl peptidase-4 (DPP-4), as well as their role in T2D, have attracted the attention of the scientific community. PTP1B plays an important role in insulin resistance and is currently one of the most promising targets for the treatment of T2D, since no available PTP1B inhibitors were still approved. DPP-4 inhibitors are among the most recent agents used in the treatment of T2D (although its use has been associated with possible cardiovascular adverse events). The antidiabetic properties of flavonoids are well-recognized, and include inhibitory effects on the above enzymes, although hitherto not therapeutically explored. In the present study, a comprehensive review of the literature of both synthetic and natural isolated flavonoids as inhibitors of PTP1B and DPP-4 activities is made, including their type of inhibition and experimental conditions, and structure-activity relationship, covering a total of 351 compounds. We intend to provide the most favorable chemical features of flavonoids for the inhibition of PTP1B and DPP-4, gathering information for the future development of compounds with improved potential as T2D therapeutic agents. [ABSTRACT FROM AUTHOR]

Previously, it has been reported that hypoalphalipoproteinemia (HA) is associated with rs17574 DDP4 polymorphism. Considering that in diabetic patients, HA is often present and is a risk factor for premature coronary artery disease (pCAD), the study aimed to evaluate the association of this polymorphism with pCAD in diabetic individuals. We genotyped the rs17574 polymorphism in 405 pCAD patients with T2DM, 736 without T2DM, and 852 normoglycemic individuals without pCAD and T2DM as controls. Serum DPP4 concentration was available in 818 controls, 669 pCAD without T2DM, and 339 pCAD with T2DM. The rs17574 polymorphism was associated with lower risk of pCAD (padditive = 0.007; pdominant = 0.003, pheterozygote = 0.003, pcodominant1 = 0.003). In pCAD with T2DM patients, DPP4 levels were lower when compared with controls (p < 0.001). In the whole sample, individuals with the rs17574 GG genotype have the lowest protein levels compared with AG and AA (p = 0.039) carriers. However, when the same analysis was repeated separately in all groups, a significant difference was observed in the pCAD with T2DM patients; carriers of the GG genotype had the lowest protein levels compared with AG and AA (p = 0.037) genotypes. Our results suggest that in diabetic patients, the rs17574G DPP4 allele could be considered as a protective genetic marker for pCAD. DPP4 concentrations were lower in the diabetic pCAD patients, and the rs17574GG carriers had the lowest protein levels. [ABSTRACT FROM AUTHOR]

Hyperglycemia-induced oxidative stress plays a key role in the impairment of the retinal neurovascular unit, an early event in the pathogenesis of DR. The aim of this study was to assess the antioxidant properties of topical administration (eye drops) of sitagliptin in the diabetic retina. For this purpose, db/db mice received sitagliptin or vehicle eye drops twice per day for two weeks. Age-matched db/+ mice were used as the control group. We evaluated retinal mRNA (RT-PCR) and protein levels (Western blotting and immunohistochemistry) of different components from both the antioxidant system (NRF2, CAT, GPX, GR, CuZnSOD, and MnSOD) and the prooxidant machinery (PKC and TXNIP). We also studied superoxide levels (dihydroethidium staining) and oxidative damage to DNA/RNA (8-hydroxyguanosine immunostaining) and proteins (nitrotyrosine immunostaining). Finally, NF-кB translocation and IL-1β production were assessed through Western blotting and/or immunohistochemistry. We found that sitagliptin protected against diabetes-induced oxidative stress by reducing superoxide, TXNIP, PKC, and DNA/RNA/protein oxidative damage, and it prevented the downregulation of NRF2 and antioxidant enzymes, with the exception of catalase. Sitagliptin also exerted anti-inflammatory effects, avoiding both NF-кB translocation and IL-1β production. Sitagliptin prevents the diabetes-induced imbalance between ROS production and antioxidant defenses that occurs in diabetic retinas. [ABSTRACT FROM AUTHOR]

Aims: This study investigated the pharmacokinetics and pharmacodynamics properties, safety and tolerability of cetagliptin. Methods: Forty‐eight healthy subjects were enrolled in this study. Three cohorts were investigated in sequential order: 50, 100 and 200 mg cetagliptin. Positive control (sitagliptin 100 mg) was designed as open label. Blood samples were collected and analysed for pharmacokinetic and pharmacodynamic properties. Safety and tolerability were assessed throughout the study. Results: Following multiple oral doses, cetagliptin was rapidly absorbed and reached peak plasma concentrations after approximately 1.0–1.5 hours. Plasma cetagliptin concentrations increased at a rate greater than dose. Accumulation of cetagliptin was modest, and steady state was generally achieved at day 5. Doses ≥50 mg of cetagliptin administered once daily will result in sustained dipeptidyl peptidase‐4 (DPP‐4) inhibition (≥80%). The plasma concentration giving 50% of maximum drug effect of DPP‐4 inhibition for cetagliptin (5.29 ng/mL) was lower than that of sitagliptin (7.03 ng/mL). Active glucagon‐like‐1 peptide (GLP‐1) concentrations were significantly increased in the cetagliptin groups by 2.3‐ to 3.1‐fold at day 1 and 3.1‐ to 3.6‐fold at steady state compared with that of placebo, and active GLP‐1 concentrations were increased with increasing dose. Compared with sitagliptin, doses ≥100 mg once daily of cetagliptin produced postprandial increases in active GLP‐1 level and induced to long‐lasting glucose‐lowering efficacy. Cetagliptin was well tolerated across all doses studied. Conclusion: Cetagliptin demonstrates the great potential for treatment with type 2 diabetes patients based on the inhibition of DPP‐4, the increase in GLP‐1 and insulin, the decrease in glucose, and might be more effective in DPP‐4 inhibition than sitagliptin. [ABSTRACT FROM AUTHOR]

Dipeptidyl peptidase-4 (DPP-4) inhibitors have been the most widely used for type 2 diabetes (T2D) available worldwide since 2006. DPP-4 inhibitors exert their effects by inhibiting dipeptidyl peptidase-4 to increase the concentration of endogenous incretin hormones (incretin hormone analogues and incretin potentiators) and promote insulin secretion, thereby acting as a glucose regulator. Evogliptin is a new member of the DPP-4 inhibitor family with high selectivity and low risk of hypoglycemia, and extensive clinical data has been accumulated in its treatment of T2D since its introduction in October 2015. This review summarized the recently reported studies associated with the pharmacokinetics, pharmacodynamics, safety and tolerability, and clinical application of evogliptin for managing T2D. We searched the MEDLINE and PubMed databases with the titles 'evogliptin' to identify all the information. The abstracts and posters of the annual meetings of ADA and EASD and clinicalTrials.gov. have been searched up to now. Evogliptin is a potent, orally effective, and highly selective DPP-4 inhibitor that is not only indicated for the treatment of T2D but may also be beneficial to arterial inflammation and atherosclerosis, with good safety and tolerance. [ABSTRACT FROM AUTHOR]

Dipeptidyl peptidase‐4 (DPP4) has been proven to exert its functions by both enzymatic and nonenzymatic pathways. The nonenzymatic function of DPP4 in diabetes‐associated cognitive impairment remains unexplored. We determined DPP4 protein concentrations or its enzymatic activity in type 2 diabetic patients and db/db mice and tested the impact of the non‐enzymatic function of DPP4 on mitochondrial dysfunction and cognitive impairment both in vivo and in vitro. The results show that increased DPP4 activity was an independent risk factor for incident mild cognitive impairment (MCI) in type 2 diabetic patients. In addition, DPP4 was highly expressed in the hippocampus of db/db mice and contributed to mitochondria dysfunction and cognitive impairment. Mechanistically, DPP4 might bind to PAR2 in the hippocampus and trigger GSK‐3β activation, which downregulates peroxisome proliferator‐activated receptor gamma coactivator 1 alpha expression and leads to mitochondria dysfunction, thereby promoting cognitive impairment in diabetes. Our findings indicate that the nonenzymatic function of DPP4 might promote mitochondrial dysfunction and cognitive impairment in diabetes. [ABSTRACT FROM AUTHOR]

Dipeptidyl peptidase-4 (DPP4) is a ubiquitously occurring protease involved in various physiological and pathological processes ranging from glucose homeostasis, immunoregulation, inflammation to tumorigenesis. Recently, the benefits of DPP4 inhibitors as novel hypoglycemic agents on bone metabolism have attracted extensive attraction in many studies, indicating that DPP4 inhibitors may regulate bone homeostasis. The effects of DPP4 on bone metabolism are still unclear. This paper thoroughly reviews the potential mechanisms of DPP4 for interaction with adipokines, bone cells, bone immune cells, and cytokines in skeleton system. This literature review shows that the increased DPP4 activity may indirectly promote bone resorption and inhibit bone formation, increasing the risk of osteoporosis. Thus, bone metabolic balance can be improved by decreasing DPP4 activities. The substantial evidence collected and analyzed in this review supports this implication. [ABSTRACT FROM AUTHOR]

Introduction: The studies in animal models of cirrhosis suggest that dipeptidyl peptidase type 4 (DPP-4) enzymes play a crucial role in disease pathogenesis. In this clinical observational study, activity of DPP-4 and related gene expression were analysed in chronic liver disease patients. Objectives: To understand the DPP-4 enzyme activity variation in the common types of chronic liver disease by assessing plasma and peripheral blood mononuclear cell (PBMC) DPP-4 activity and comparing with healthy controls and to explore DPP-4 gene expression in PBMC. Methods: We recruited 130 study subjects in four cohorts—46 nonalcoholic fatty liver disease (NAFLD), 23 non-alcoholic cirrhosis (NAC) excluding viral aetiology, 21 alcoholic liver disease (ALC), and 40 control subjects. Blood samples were analysed for relevant biochemical parameters and plasma DPP-4 activity. PBMC fraction was used for the DPP-4 activity assay and gene expression analysis. Results: We found that lower plasma DPP-4 activity among patient cohorts but this was not statistically significant. The PBMC DPP-4 activity was significantly lower in NAFLD cohort. In the same cohort, DPP-4 gene expression in PBMC fraction was significantly increased (P < 0.05). There was significant correlation between plasma DPP-4 activity and liver injury marker alanine aminotransferase (ALT) among NAFLD (rho = 0.459, P < 0.01), NAC (rho = 0.475, P < 0.05), and ALC (rho = –0.572, P < 0.01) patients. Plasma DPP-4 activity modestly predicted ALT plasma level (beta coefficient = 0.489, P < 0.01). Conclusions: The PBMC DPP-4 activity and DPP-4 gene expression gets significantly altered in NAFLD patients. Plasma DPP-4 activity also shows correlation with ALT levels in CLD patients. The role of DPP-4 in disease pathology in NAFLD and other forms of CLD needs to be explored. [ABSTRACT FROM AUTHOR]