Influence of different dialyzer membranes on plasma fibronectin levels in hemodialyzed patients.

Plasma fibronectin (FN) was assayed in 30 patients with chronic renal failure under conservative therapy, 60 uremic patients undergoing periodic hemodialysis, and 7 patients treated by hemofiltration. Plasma FN was significantly lower in uremic patients on conservative therapy and in those who received intermittent hemodialysis than in the control group. No difference was seen between mean FN concentrations using different dialyzer membranes. Nevertheless, plasma FN levels were significantly higher in subjects after intermittent hemofiltration. There was no evidence of activation of the coagulation system or of any correlation between FN and fibrinogen values. These findings suggest that conventional hemodialysis is not effective in improving the low levels of plasma FN found in uremic patients, whereas intermittent hemofiltration raises FN. These differences may be due to the fact that during hemofiltration, even when using the same dialyzer membranes as in conventional hemodialysis, some "substances" with high molecular weight that could block the synthesis of FN could be removed.