PBMC microRNA-155 is up-regulated in chronic hemodialysis patients.

Introduction and Aims: Micro RNAs (miR) are molecules of 20-30 non-coding nucleotides regulating a multitude of biological processes. MiR-155 is a recognized biomarker of several B-cell lymphomas, and recent experimental works have associated miR-155 up-regulation with an increase of inflammatory response. This study aimed to analyze, a) basal expression of miR-155 in peripheral blood mononuclear cells (PBMC) of chronic hemodialysis (HD) patients, and b) PBMC miR-155 expression during human blood contact to low permeability polysulphone hemodialysis membranes before (long interval period) and after standard 4-hour HD sessions. Methods: PBMC miR-155 was isolated from 7 healthy laboratory individuals (CTRLs; (age 30-50 years; 3F, 4M) and 9 HD patients (age 50-75 years; 1F, 8M) using miRNeasy mini kit and quantified by real-time PCR. All HD patients were free from hematological, inflammatory or neoplastic diseases. Data are expressed as mean; ± standard error; statistical differences were identified by t-test. Results: MiR-155 relative (to CTRLs) quantity (RQ) from long period pre-HD was 3.77; ± 0.62 times higher than CTRLs (P = 0.003). No differences were instead observed after HD sessions, 3.49; ± 0.70 RQ (P = NS vs. pre-HD). Conclusions: These preliminary data from HD PBMC show a significant up-regulation of miR-155 when compared to CTRLs. It also looks that interaction of PBMC to low permeability polysulphone membranes doesn’t increase monocyte miR-155 basal up-regulation. Further studies will be carried out to clarify the role of HD and renal failure for miR-155 expression.