Role Of Dipeptidyl Peptidase IV Research Articles

The role of dipeptidyl peptidase-IV in abdominal aortic aneurysm pathogenesis: A systematic review.

Abdominal aortic aneurysm (AAA) is an important vascular disease carrying significant mortality implications due to the risk of aneurysm rupture. Current management relies exclusively on surgical repair as there is no effective medical therapy. A key element of AAA pathogenesis is the chronic inflammation mediated by inflammatory cells releasing proteases, including the enzyme dipeptidyl peptidase IV (DPP-IV). This review sought to recapitulate available evidence on the involvement of DPP-IV in AAA development. Further, we assessed the experimental use of currently available DPP-IV inhibitors for AAA management in murine models. Embase, Medline, PubMed, and Web of Science databases were utilised to access the relevant studies. The review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA). A narrative synthesis approach was used. Sixty-four studies were identified from the searched databases; a final 11 were included in the analysis. DPP-IV was reported to be significantly increased in both AAA tissue and plasma of patients and correlated with AAA growth. DPP-IV inhibitors (sitagliptin, vildagliptin, alogliptin, and teneligliptin) were all shown to attenuate AAA formation in murine models by reducing monocyte differentiation, the release of reactive oxygen species (ROS), and metalloproteinases (MMP-2 and MMP-9). DPP-IV seems to play a role in AAA pathogenesis by propagating the inflammatory microenvironment. This is supported by observations of decreased AAA formation and reduction in macrophage infiltration, ROS, matrix MMPs, and interleukins following the use of DPP-IV inhibitors in murine models. There is an existing translational gap from preclinical observations to clinical trials in this important and novel mechanism of AAA pathogenesis. This prior literature highlights the need for further research on molecular targets involved in AAA formation.

Evaluation of Dipeptidyl Peptidase-IV Inhibitor Use in the Inpatient Setting

Background: The American Diabetes Association recommends discontinuing non-insulin antihyperglycemic therapy during hospitalization and utilizing a basal insulin-containing regimen for patients with type 2 diabetes mellitus (T2DM). Limited research is available on the role of dipeptidyl peptidase-IV (DPP-IV) inhibitors in an inpatient real-world patient population. Objective: To determine the efficacy of DPP-IV inhibitor therapy in hospitalized patients with T2DM. Methods: Adult patients with T2DM and received at least one dose of DPP-IV inhibitor during hospitalization were included. The primary outcome was to determine the mean daily blood glucose (BG) readings in the overall patient population. Secondary outcomes included comparing study groups and evaluating mean daily blood glucose, hospital length of stay (LOS) and incidence of hypoglycemia. Results: One hundred and ninety-two patients were identified: 39 patients (20.3%) received DPP-IV inhibitor monotherapy, 104 (54.2%) received DPP-IV inhibitor plus oral antihyperglycemics and 49 (25.5%) received DPP-IV inhibitor plus insulin. Mean daily BG in the entire study population was 158.7 mg/dL (131-187.5). Mean daily BG was significantly different between groups (117 mg/dL [103.5-132.3] vs. 160.7 mg/dL [133-181.1] vs. 179.4 mg/dL [153.8-216.6]; (P < 0.001). Hypoglycemic events were higher in the DPP-IV inhibitor plus insulin group (2.6% vs. 3.8% vs. 16.3%; P = 0.008). There were no significant differences in hospital LOS (2 days [1-4] vs. 3 days [1-5] vs. 4 days [2-6.5]; P = 0.051). Conclusions: Inpatient DPP-IV inhibitor use was associated with mean daily BG within goal range. Administering DPP-IV inhibitors in the inpatient setting should be considered in hospitalized patients with controlled T2DM.

Psoriasiform eruption triggered by a dipeptidyl peptidase IV inhibitor

Psoriatic patients have a higher prevalence of diabetes mellitus type 2 (DM). Since dipeptidyl peptidase IV (DPP-IV) dysregulation is present in DM and psoriasis, DPP-IV inhibitors have been proposed as therapeutic agents for both conditions. We report a psoriasiform eruption induced by sitagliptin, a DPP-IV inhibitor. The role of DPP-IV in the pathogenesis of DM is well established; however data on psoriatic patients is contradictory. More studies are required to elucidate the effect of DPP-IV inhibitors and their relationship with DM and psoriasis.

Coupled expression of dipeptidyl peptidase-IV and fibroblast activation protein-α in transformed astrocytic cells

Dipeptidyl peptidase-IV (DPP-IV) and fibroblast activation protein-α (FAP) are speculated to participate in the regulation of multiple biological processes, because of their unique enzymatic activity, as well as by non-hydrolytic molecular interactions. At present, the role of DPP-IV and FAP in the development and progression of various types of tumors, including glioblastoma, is intensively studied, and their functional crosstalk is hypothesized. In this article, we describe the correlative expression of DPP-IV and FAP mRNA in primary cell cultures derived from human glioblastoma and associated expression dynamics of both molecules in astrocytoma cell lines depending on culture conditions. Although the molecular mechanisms of DPP-IV and FAP co-regulations remain unclear, uncoupled expression of transgenic DPP-IV and the endogenous FAP suggests that it occurs rather at the transcriptional than at the posttranscriptional level. Understanding of the expressional and functional coordinations of DPP-IV and FAP may help clarify the mechanisms of biological roles of both molecules in transformed astrocytic cells.

DPP4 Inhibitors: a new approach in diabetes treatment

The role of dipeptidyl peptidase-IV (DPP4) as both a regulatory enzyme and a signalling factor has been evaluated and described in many studies. DPP4 inhibition results in increased blood concentration of the incretin hormones glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP). This causes an increase in glucose-dependent stimulation of insulin secretion, resulting in a lowering of blood glucose levels. Recent studies have shown that DPP4 inhibitors can induce a significant reduction in glycosylated haemoglobin (HbA(1c)) levels, either as monotherapy or as a combination with other antidiabetic agents. Research has also demonstrated that DPP4 inhibitors portray a very low risk of hypoglycaemia development. This review article focuses on the two leading agents of this category (sitagliptin and vildagliptin), providing an overview of their function along with the latest data regarding their clinical efficacy as antidiabetic agents.

Role of dipeptidyl peptidase IV in regulating activity of Na+/H+ exchanger isoform NHE3 in proximal tubule cells.

We recently reported that NHE3 exists in multimeric complexes with dipeptidyl peptidase IV (DPPIV) in renal brush-border membranes. To examine the possible role of DPPIV in modulating NHE3 activity, we evaluated whether specific competitive inhibitors that bind to the active site of DPPIV affect NHE3 activity in the OKP line of opossum kidney proximal tubule cells. The DPPIV inhibitors diprotin A and P32/98 significantly reduced NHE3 activity, whereas the inactive isomer P34/98 had no effect. DPPIV inhibitors did not reduce the activity of another brush-border transport process, Na-phosphate cotransport. Effects of DPPIV inhibitors on NHE3 activity were not associated with detectable changes in amount or apparent molecular weight of NHE3 or in NHE3 surface expression. To investigate the signaling mechanisms involved in modulation of NHE3 activity by DPPIV, we used inhibitors of protein kinase pathways known to regulate NHE3. Whereas the PKA inhibitor H-89 failed to block the effect of DPPIV inhibitors, the tyrosine kinase inhibitor genistein alone caused a decrement in NHE3 activity very similar in magnitude to that caused by P32/98. We also found that the effects of genistein and P32/98 on NHE3 activity were not additive. In contrast, forskolin/IBMX and P32/98 had additive inhibitory effects on NHE3 activity. These findings suggested that the effect of DPPIV inhibitors to reduce NHE3 activity results from inhibition of a tyrosine kinase signaling pathway rather than by activation of PKA. We conclude that DPPIV plays an unexpected role in modulating Na+/H+ exchange mediated by NHE3 in proximal tubule cells.

Detection of dipeptidyl peptidase IV in glioma C6 and neuroblastoma SK-N-SH cell lines

The dipeptidyl peptidase IV (DPP-IV) activity of the rat glioma cell line C6 and the human neuroblastoma cell line SK-N-SH was investigated. DPP-IV fluorescent substrate was cleaved by both cell lines. The pH reaction optimum determined was typical for DPP-IV described in other cell models. The reaction was inhibited by specific inhibitors diprotins A and B. Enzyme activity was localized, both on the cell surface and intracellularly. Most of the DPP-IV activity was membrane bound. However, soluble intra-cellular activity was found in both cell lines. Secreted activity was not detected in either cell line. In the C6 line, but not in the SK-N-SH line, we demonstrated depression of the ratio of cell surface to total cell DPP-IV activity at higher cell densities, indicating possible enzyme redistribution during cell growth in culture. Identification of DPP-IV activity is the first step in our study of the role of DPP-IV in the neural system.