Peritoneal sclerosis: role of plasticizers in stimulating interleukin-1 production

The role of plasticizers (PLS) in inducing water flow inhibition and peritoneal sclerosis has been demonstrated in both in vivo and in vitro studies. Interleukin-1 (IL-1) has been shown to be a regulator of fibroblast proliferation as well as collagenase production. The aim of this study was to evaluate the role of PLS in stimulating mononuclear cell IL-1 secretion. Two cultures containing 10(3) cells/mL were obtained from 14 healthy subjects. One was used as the control, and the other was mixed with diethylhexylphthalate (DEHP) to reach a final concentration of 2.8 x 10(-3) M. After 4 hours the samples were centrifuged, and the supernatants were tested by radioimmunoassay for IL-1 alpha and IL-1 beta. The results showed a significant increase in both IL-1 alpha and IL-1 beta production in DEHP-stimulated cells in comparison to the controls: 42.6 +/- 15.4 versus 29.3 +/- 10 ng/L (p < 0.015) for IL-1 alpha, and 153.6 +/- 55 versus 113.6 +/- 32 ng/L (p < 0.03) for IL-1 beta In conclusion, PLS added to mononuclear cells were able to induce IL-1 secretion. This mechanism could be responsible, at least in part, for the development of peritoneal sclerosis. Thus the employment of plasticizer-free bags should be elective in peritoneal dialysis.