Regulation of synthesis and roles of hyaluronan in peritoneal dialysis

Endogenously produced hyaluronan contributes to the regulation of peritoneal adhesion development

Peritoneal adhesions are postsurgical fibrotic complications connected to peritoneal inflammation. The exact mechanism of development is unknown; however, an important role is attributed to activated mesothelial cells (MCs) overproducing macromolecules of extracellular matrix (ECM), including hyaluronic acid (HA). It was suggested that endogenously-produced HA contributes to the regulation of different fibrosis-related pathologies. However, little is known about the role of altered HA production in peritoneal fibrosis. We focused on the consequences of the increased turnover of HA in the murine model of peritoneal adhesions. Changes of HA metabolism were observed in early phases of peritoneal adhesion development in vivo. To study the mechanism, human MCs MeT-5A and murine MCs isolated from the peritoneum of healthy mice were pro-fibrotically activated by transforming growth factor β (TGFβ), and the production of HA was attenuated by two modulators of carbohydrate metabolism, 4-methylumbelliferone (4-MU) and 2-deoxyglucose (2-DG). The attenuation of HA production was mediated by upregulation of HAS2 and downregulation of HYAL2 and connected to the lower expression of pro-fibrotic markers, including fibronectin and α-smooth muscle actin (αSMA). Moreover, the inclination of MCs to form fibrotic clusters was also downregulated, particularly in 2-DG-treated cells. The effects of 2-DG, but not 4-MU, were connected to changes in cellular metabolism. Importantly, the inhibition of AKT phosphorylation was observed after the use of both HA production inhibitors. In summary, we identified endogenous HA as an important regulator of peritoneal fibrosis, not just a passive player during this pathological process.

Associations between liver function parameters and poor clinical outcomes in peritoneal dialysis patients

Patients with end-stage renal disease (ESRD) have significantly lower survival rates compared with the general population of the same age. Peritoneal dialysis (PD) is an effective treatment for patients with ESRD, but the clinical outcome of PD patients is still not promising. The survival of PD patients is associated with various clinical factors, and exploring some valid risk predictors may be beneficial for this population. In this review, by integrating the latest research, we summarized the association of some common and novel liver function parameters (ALT, AST, ALP, GGT, serum bilirubin, pre-albumin, albumin, albumin-globulin ratio [AGR], serum ferritin, and hyaluronic acid) with clinical outcomes in PD patients. It may contribute to a better understanding of potential risk factors and help to develop strategies to prevent the disease progression.