Differences in kidney-specific DPP-4 inhibition by linagliptin and sitagliptin

Individual dipeptidyl peptidase-4 inhibitors and acute kidney injury in patients with type 2 diabetes: A systematic review and network meta-analysis

This network meta-analysis of randomized controlled trials aimed to determine whether any individual dipeptidyl peptidase-4 (DPP-4) inhibitors increase the risk of acute kidney injury (AKI). The Medical Literature Analysis and Retrieval System Online via PubMed, the Cochrane Central Register of Controlled Trials and ClinicalTrials.gov were systematically searched to identify relevant studies. The primary outcome was AKI. A frequentist network meta-analysis was performed using a random-effects model to account for heterogeneity. Twenty-nine studies involving 56 117 participants were included. There were 918 cases of AKI (1.63%). The risk of bias was generally considered to be low. The only DPP-4 inhibitor that significantly increased the frequency of AKI when compared with placebo was sitagliptin (risk ratio 1.65, 95% confidence interval 1.22-2.23). However, because one study showed significant outliers in the funnel plot, in a highly heterogeneous population composed solely of patients undergoing surgery for coronary artery bypass graft, we conducted a post-hoc sensitivity analysis to exclude this study. The results showed no statistically significant difference in the risk of AKI between sitagliptin and placebo. Individual DPP-4 inhibitors do not appear to increase the risk of AKI. However, sitagliptin may be associated with AKI in patients with underlying severe cardiovascular disease.

Linagliptin treatment is associated with altered cobalamin (VitB12) homeostasis in mice and humans

Linagliptin is a dipeptidyl peptidase-4 (DPP-4) inhibitor used for the treatment of type 2 diabetes, with additional beneficial effects for the kidney. Treatment of mice with linagliptin revealed increased storage of cobalamin (Cbl, Vitamin B12) in organs if a standard Cbl diet (30 µg Cbl/kg chow) is given. In order to translate these findings to humans, we determined methylmalonic acid (MMA), a surrogate marker of functional Cbl homeostasis, in human plasma and urine samples (n = 1092) from baseline and end of trial (6 months after baseline) of the previously completed MARLINA-T2D clinical trial. We found that individuals with medium Cbl levels (MMA between 50 and 270 nmol/L for plasma, 0.4 and 3.5 µmol/mmol creatinine for urine, at baseline and end of trial) exhibited higher MMA values at the end of study in placebo compared with linagliptin. Linagliptin might inhibit the N-terminal degradation of the transcobalamin receptor CD320, which is necessary for uptake of Cbl into endothelial cells. Because we demonstrate that linagliptin led to increased organ levels of Cbl in mice, sustained constant medium MMA levels in humans, and inhibited CD320 processing by DPP-4 in-vitro, we speculate that linagliptin promotes intra-cellular uptake of Cbl by prolonging half-life of CD320.

CD161a-positive natural killer (NK) cells and α-smooth muscle actin-positive myofibroblasts were upregulated by extrarenal DPP4 in a rat model of acute renal rejection

AIMS

Systemic inhibition of dipeptidyl peptidase 4 (DPP4) showed a protective effect in several transplant models. Here we assessed the specific role of extrarenal DPP4 in renal transplant rejection.

METHODS

Kidneys from wildtype (wt) F344 rats were either transplanted in wt Dark Agouti or congenic rats not expressing DPP4. The remaining, not transplanted donor kidney served as healthy controls. To investigate early inflammatory events rats were sacrificed 3 days after transplantation and kidneys were evaluated for inflammatory cells, capillary rarefaction, proliferation, apoptosis and myofibroblasts by immunohistochemistry.

RESULTS

Capillary ERG-1-positive endothelial cells were significantly more abundant in renal cortex when transplanted into DPP4 deficient compared to wt recipients. In contrast, TGF-ß and myofibroblasts were reduced by more than 25% in kidneys transplanted into DPP4 deficient compared to wt recipients. Numbers of CD161a-positive NK-cells were significantly lower in allografts in DPP4 deficient compared to wt recipients. Numbers of all other investigated immune cells were not affected by the lack of extrarenal DPP4.

CONCLUSION

In early transplant rejection extrarenal DPP4 is involved in the recruitment of NK-cells and early fibrosis. Beneficial effects were less pronounced than reported for systemic DPP4 inhibition, indicating that renal DPP4 is an important player in transplantation-mediated injury.

DPP4 Inhibitor Sitagliptin Enhances Lymphocyte Recruitment and Prolongs Survival in a Syngeneic Ovarian Cancer Mouse Model

Simple Summary

The role of immunity in the development and progression of epithelial ovarian cancer (EOC) is well established. Poor T-cell infiltration is associated with mortality in EOC patients, and recent evidence has suggested that the enzyme DPP4 plays a role in this process. The aim of our study was to evaluate the potential of the clinically-approved DPP4-inhibitor sitagliptin to improve immune responses in mice with EOC. We showed that sitagliptin improved CD8+ T-cell responses in an EOC mouse model, consequently reducing metastatic burden and prolonging survival. These data provide a rationale for the use of DPP4-inhibitors as a second-line treatment for EOC.

Abstract

Immunity plays a key role in epithelial ovarian cancer (EOC) progression with a well-documented correlation between patient survival and high intratumoral CD8+ to T regulatory cell (Treg) ratios. We previously identified dysregulated DPP4 activity in EOCs as a potentially immune-disruptive influence contributing to a reduction in CXCR3-mediated T-cell infiltration in solid tumours. We therefore hypothesized that inhibition of DPP4 activity by sitagliptin, an FDA-approved inhibitor, would improve T-cell infiltration and function in a syngeneic ID8 mouse model of EOC. Daily oral sitagliptin at 50 mg/kg was provided to mice with established primary EOCs. Sitagliptin treatment decreased metastatic tumour burden and significantly increased overall survival and was associated with significant changes to the immune landscape. Sitagliptin increased overall CXCR3-mediated CD8+ T-cell trafficking to the tumour and enhanced the activation and proliferation of CD8+ T-cells in tumour tissue and the peritoneal cavity. Substantial reductions in suppressive cytokines, including CCL2, CCL17, CCL22 and IL-10, were also noted and were associated with reduced CD4+ CD25+ Foxp3+ Treg recruitment in the tumour. Combination therapy with paclitaxel, however, typical of standard-of-care for patients in palliative care, abolished CXCR3-specific T-cell recruitment stimulated by sitagliptin. Our data suggest that sitagliptin may be suitable as an adjunct therapy for patients between chemotherapy cycles as a novel approach to enhance immunity, optimise T-cell-mediated function and improve overall survival.

The dipeptidyl peptidase 4 inhibitor linagliptin ameliorates renal injury and accelerated resolution in a rat model of crescentic nephritis

BACKGROUND AND PURPOSE

Dipeptidyl peptidase 4 (DPP-4) inhibitors are a class of oral glucose-lowering drugs used in the treatment of type 2 diabetes. In a pilot study using human kidney biopsies, we observed high DPP-4 expression in early crescent formation. This glomerular lesion occurs in different kidney diseases and is a hallmark in the pathogenesis of renal dysfunction. Therefore, we investigated the potential involvement of DPP-4 in the pathogenesis of nephritis induced by anti-glomerular basement membrane (GBM) antibody in rats.

EXPERIMENTAL APPROACH

Linagliptin and vehicle were used to treat anti-GBM nephritis in a 2- and 8-week regimen, that is either preventive or therapeutic (treatment started 7 days or 4 weeks after disease induction). Kidney function, morphologic changes, inflammation and fibrosis were monitored.

KEY RESULTS

In the long-term experiment, linagliptin preventive treatment in anti-GBM nephritic rats significantly reduced the number of crescents, glomerulosclerosis, tubular injury and renal fibrosis, compared with those in untreated nephritic rats. Both linagliptin regimes significantly lowered the number of Pax8+ cells on the glomerular tuft in anti-GBM nephritis, indicating accelerated resolution of the cellular crescents. The linagliptin treatment did not change the podocyte stress in both therapeutic groups. Therapeutic intervention with linagliptin resulted in weaker amelioration of renal disease on Week 8 than did preventive intervention.

CONCLUSION AND IMPLICATIONS

DPP-4 inhibition with linagliptin ameliorates renal injury in a rat model of anti-GBM, indicating that linagliptin not only is a secure therapy in diabetes but also can improve resolution of glomerular injury and healing in non-diabetic renal disease.

Reno-protective effect of linagliptin against gentamycin nephrotoxicity in rats

BACKGROUND

Recent studies demonstrated the reno-protective effects of two dipeptidyl peptidase-4 (DPP-4) inhibitors, saxagliptin and sitagliptin, against gentamycin-induced renal injury. However, none of these studies investigated whether renal DPP-4 contributes to the pathogenesis of this nephrotoxicity or not. This prompted us to test this hypothesis and to assess, for the first time, the potential reno-protective effect of linagliptin and whether this action is related or not to DPP-4 inhibition. Lingliptin was chosen since it is mainly excreted through a non-renal pathway and can therefore be used safely in individuals with renal injury.

METHODS

Male Sprague-Dawley rats were administered gentamycin (100 mg/kg/day, ip for 10 days) alone or combined with linagliptin (3 mg/kg/day, orally for 14 days). Gentamycin was administered once daily during the last ten days of the linagliptin treatment.

RESULTS

Linagliptin administration ameliorated gentamycin-induced renal injury and restored renal functional, oxidative, inflammatory, apoptotic and histopathological changes. Furthermore, the current study highlighted the role of increased plasma and renal DPP-4 in the pathogenesis of gentamycin renal insults and showed that the potential reno-protective effect of linagliptin is partly, mediated via inhibition of DPP-4, in addition to other antioxidant, anti-inflammatory and anti-apoptotic actions.

CONCLUSION

Linagliptin may serve as a beneficial adjutant to reduce gentamycin-induced renal injury.