Peritoneal dialysis induces alterations in the transcriptome of peritoneal cells before detectible peritoneal functional changes

Long-term peritoneal dialysis (PD) is associated with functional and structural alterations of the peritoneal membrane. Inflammation may be the key moment, and, consequently, fibrosis may be the end result of chronic inflammatory reaction. The objective of the present study was to identify genes involved in peritoneal alterations during PD by comparing the transcriptome of peritoneal cells in patients with short- and long-term PD. Peritoneal effluent of the long dwell of patients with stable PD was centrifuged to obtain peritoneal cells. The gene expression profiles of peritoneal cells using microarray between patients with short- and long-term PD were compared. Based on microarray analysis, 31 genes for quantitative RT-PCR validation were chosen. A 4-h peritoneal equilibration test was performed on the day after the long dwell. Transport parameters and protein appearance rates were assessed. Genes involved in the immune system process, immune response, cell activation, and leukocyte and lymphocyte activation were found to be substantially upregulated in the long-term group. Quantitative RT-PCR validation showed higher expression of CD24, lymphocyte antigen 9 (LY9), TNF factor receptor superfamily member 4 (TNFRSF4), Ig associated-alpha (CD79A). chemokine (C-C motif) receptor 7 (CCR7), carcinoembryonic antigen-related cell adhesion molecule 1 (CEACAMI), and IL-2 receptor-alpha (IL2RA) in patients with long-term PD, with CD24 having the best discrimination ability between short- and long-term treatment. A relationship between CD24 expression and genes for collagen and matrix formation was shown. Activation of CD24 provoked by pseudohypoxia due to extremely high glucose concentrations in dialysis solutions might play the key role in the development of peritoneal membrane alterations.