Polymethylmethacrylate efficacy in reduction of renal itching in hemodialysis patients: Crossover study and role of tumor necrosis factor-alpha

Pruritus is one of the major unsolved problems for patients receiving regul ar hemodialysis. In this study, we conducted a 6 month prospective and cros sover trial to investigate the effect of polymethylmethacrylate (PMMA) memb rane for renal itching. We also examined the role of the tumor necrosis fac tor (TNF)-alpha system for pruritus in hemodialysis patients. We assessed t he degree of skin itching and measured circulating levels of TNF-alpha and soluble TNF receptors (sTNFR-I, sTNFR-II) in 19 patients using hemodialysis , complicated by prolonged severe pruritus for 6 months. Serum sTNFR-I and II levels were significantly elevated in hemodialysis patients compared to normal subjects. Serum sTNFR-II levels were significantly and negatively co rrelated with serum albumin (r = -0.602, p = 0.007). A significant positive relationship was also found between sTNFR-I and erythropoietin dosage (r = 0.554, p = 0.016). However, no association was found between the degree of pruritus and circulating sTNFR-I and II values. Skin itching scale was sig nificantly decreased from 2.7 +/- 0.2 to 2.1 +/- 0.3 following the use of P MMA membrane for 3 months (p < 0.05). In contrast, there was no change in i tching scales during 3 months of conventional therapy (2.2 +/- 0.3 versus 2 .2 +/- 0.3, p = NS). PMMA itself did not affect serum TNF-alpha and sTNFR v alues as well as conventional dialyzer membranes. These findings suggested that the PMMA dialyzer can improve renal itching not mediated through the m odification of the TNF-alpha system.