Role of Adhesion Molecules in Mononuclear Cell Apoptosis Induced by Cuprophan Hemodialysis Membranes

Abstract

Background/Aim: Hemodialysis with Cuprophan (CU) membranes induces mononuclear cell activation, leading to increased expression of adhesion molecules, formation of cell aggregates, and apoptosis. It is likely that structure(s) of the CU membrane interact with mononuclear cell surface molecules which transduce biochemical signals to the cell. Interactions between adhesion molecules and extracellular matrix have been implicated in cell activation, proliferation, and/or apoptosis. In the present work, we study whether adhesion molecules may be involved in CU-induced mononuclear cell aggregation and/or apoptosis. Methods: The present study was performed using THP-1 cells, a human monocytic cell line, cultured in the presence of the CU membrane. CD11b and CD54 expression was studied with fluorescent monoclonal antibodies. Cell aggregation was quantified using a phase-contrast microscope. Apoptosis was evaluated by either light microscopy or annexin V labeling. Results: The results show that incubation of CU membranes with the proteins CD11b, CD18, and CD54 or the blockade of these cell surface molecules with specific monoclonal antibodies inhibited the CU-induced aggregation and apoptosis in a dose-dependent manner. Conclusion: These results suggest that CU membranes interact selectively with these specific proteins to induce cell activation which ultimately results in apoptosis.