ADAM19 participated in peritoneal fibrosis by regulating M2 macrophage polarization in peritoneal dialysis patients.

Peritoneal fibrosis, driven by M2 macrophage polarization, limits the long-term application of peritoneal dialysis (PD). Although ADAM19 is known to mediate fibrosis in other organs, its specific role in PD-associated peritoneal fibrosis remains unclear. PD patients were enrolled in a single center and divided into three groups depending on the PD time. Demographic and clinical data were collected. We detected the expressions of ADAM19, Notch1, Fibrosis-associated protein, chemokines and inflammatory factors in the peritoneum dialysis effluent by real-time PCR and western-blot assays. Macrophages were identified through flow cytometry. Then we analysis the relationship between ADAM19 and clinical data in PD patients. Furthermore, we established mouse models for peritoneal fibrosis to verify the biological function of ADAM19 in regulating macrophage polarization. In the long-term group, the fibrotic proteins (Fibronectin, α-SMA) and inflammatory factors (IL-6, IL-10) and chemokines (CCL5, CCL2, CXCL16) were higher than short-term group and more macrophages polarized towards M2. ADAM19 expression was linearly correlated with dialysis time and Kt/v. The AUROC of ADAM19 was 0.738 to identify the predictive value for peritoneal dialysis adequacy. The cut-off of ADAM19 RNA level was 7.84. In logistic regression models, higher ADAM19 (≥ 7.84) was also independently associated with lower Kt/v (< 1.67). Additionally, the results revealed a moderate increment of M1 macrophage (CD86+) and enormous rise of M2 macrophage (CD206+) with high-glucose dialysis fluid in mice model. Furthermore, the 8-week G4.25% group showed significant growth of M2 macrophage compared to the 4-week G4.25% group, indicating that prolonged dialysis duration has a more pronounced effect on promoting M2 polarization of macrophages via ADAM19/Notch1 signaling pathway. Through stimulating chemokines and inflammatory factors, ADAM19 regulated macrophage polarization and was correlated to the progression of peritoneal fibrosis. ADAM19 is expected to be a novel indicator for detecting peritoneal ultrafiltration function in PD patients.