Lixisenatide attenuates advanced glycation end products (AGEs)-induced degradation of extracellular matrix in human primary chondrocytes

Osteoarthritis (OA) poses a growing threat to the health of the global population. Accumulation of advanced glycation end-products (AGEs) has been shown to upregulate expression of degradative enzymes such as matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) in chondrocytes, which leads to excessive degradation of type II collagen and aggrecan in the articular extracellular matrix (ECM). In the present study we investigated the effects of the GLP-1 agonist lixisenatide, a widely used type II diabetes medication, on AGEs-induced decreased mitochondrial membrane potential (MMP), degradation of ECM, oxidative stress, expression of cytokines including interleukin (IL)-1β and IL-6, and activation of nuclear factor kappa B (NF-κB). Our findings indicate that lixisenatide significantly ameliorated the deleterious effects of AGEs in a dose-dependent manner. Thus, lixisenatide has potential as a safe and effective treatment for OA and other AGEs-induced inflammatory diseases.

Sitagliptin ameliorates advanced glycation end-product (AGE)-induced degradation of extracellular matrix in human primary chondrocytes

Accumulation of advanced glycation end-products (AGEs) increases inflammation and triggers processes involved in the pathogenesis of osteoarthritis (OA). As a major debilitating age-related disease, it is imperative that novel therapies for OA be sought. In the present study, we investigated the effects of the selective dipeptidyl peptidase IV (DPP-4) inhibitor sitagliptin in human primary chondrocytes exposed to insult by AGEs to elucidate the potential role of sitagliptin in the treatment of OA. Our findings show that inhibition of DPP-4 by sitagliptin could reduce oxidative stress, increase cell viability and prevent degradation of type II collagen and aggrecan by matrix metalloproteinases (MMPs) and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS) induced by AGEs in human primary chondrocytes. Mechanistically, we found that sitagliptin inhibited AGEs-induced nuclear translocation of p65 protein and drastically decreased the luciferase activity of NF-κB. These findings indicate that sitagliptin may have potential as a novel therapeutic option for the treatment and prevention of OA.

Cardiac fibrosis in regenerative medicine: destroy to rebuild

The major limitations for cardiac regeneration in patients after myocardial infarction (MI) are the wide loss of cardiomyocytes and the adverse structural alterations of extracellular matrix (ECM). Cardiac fibroblast differentiation into myofibroblasts (MFB) leads to a huge deposition of ECM and to the subsequent loss of ventricular structural integrity. All these molecular events depict the fundamental features at the basis of the post-MI fibrosis and deserve in depth cellular and molecular studies to fill the gap in the clinical practice. Indeed, to date, there are no effective therapeutic approaches to limit the post-MI massive fibrosis development. In this review we describe the involvement of integrins and a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS)/ADAMTS-like (ADAMTSL) proteins in cardiac reparative pro-fibrotic response after MI, proposing some of them as novel potential pharmacological tools.