Uremic toxins and adenosine deaminase activity.

Predialysis erythrocyte adenosine deaminase activity was depressed in 12 of 20 patients receiving hemodialysis. In contrast, in 17 patients a marked rise in enzyme activity was observed subsequent to dialysis. Six patients had evidence of neuropathy. Predialysis plasma inhibited normal enzyme activity by an average of 36%, but postdialysis plasma had minimal inhibitory effect. A low molecular weight substance or substances, isolated from the dialysate of uremics, inhibited adenosine deaminase activity by 38%. Three patients having the longest courses of dialysis had no neuropathy and showed no depression of activity, with their plasma failing to inhibit normal activity. It is suggested that accumulation of low molecular weight toxins that depress adenosine deaminase activity may lead to myelin sheath degeneration with subsequent neuropathy. By removing the inhibitor, dialysis may permit nerve repair and eventual recovery.