Contrasting effect of hemodialysis and peritoneal dialysis on the inhibition of in vitro calcification by uremic serum.

Our findings support the earlier observation of Yendt, Connor and Howard that uremic serum inhibits the calcification of rachitic rat cartilage in vitro. We also confirmed their studies showing that this inhibition is not the consequence of increased levels of serum magnesium or blood urea. In addition, we have shown that aqueous solutions of creatinine and uric acid in concentrations up to 20 mg./100 ml. do not cause any inhibition.Hemodialysis of uremic patients does not change the inhibitory activity of their blood. In contrast, after 24 hours of peritoneal dialysis, the blood of most patients does not inhibit calcification.The inhibitory activity of uremic serum, observed in vitro, may be important in the pathogenesis of osteomalacia in patients with renal failure. Failure of hemodialysis to alter this activity may contribute to the progression of renal osteodystrophy in patients on maintenance hemodialysis.