Short- and medium-term increase of CA125 in peritoneal effluent using a neutral-pH solution

Abstract

Objective: To investigate the effects of an alternative peritoneal dialysis (PD) solution composed of a lactate/ bicarbonate (Lac/Bic) mixture (35/2 mmol/L), pH 7.0, on the appearance of cancer antigen 125 (CA125) in the peritoneal effluent.

Methods: Eight stable PD patients received a conventional solution containing 35 mmol/L lactate (Lac) for 11.9 +/- 9.2 months, and then changed to Lac/Bic for 3.1 +/- 0.7 months. Each patient acted as his/her own control.

Results: We studied 4 males and 4 females with a mean age of 57.4 +/- 16.8 years. Higher concentrations (U/mL) (p < 0.005) and appearance rates (AR) (U/min) (p < 0.05) of CA125 in the dialysate were observed with Lac/Bic than with Lac, during the sampling times of the peritoneal equilibration test (10, 120, and 240 minutes) and in the overnight effluent: CA125 5.7 versus 0.6, 18.9 versus 1.9, 29.7 versus 3.7, and 43.2 versus 5.5 U/mL; and AR 1177 versus 125,354 versus 36,297 versus 37, and 194 versus 26 U/min, respectively. Mean CA125 content in the 24-hour dialysate was 34.2 U/min (baseline) and 30.9 U/min (11.9 months) with Lac, and 207.9 U/min and 185 U/min after 1.6 and 3.1 months with Lac/Bic (p = 0.009). The intraperitoneal pH was more physiological during the dwell with the Lac/Bic solution.

Conclusions: The CA125 levels in the peritoneal effluent with Lac/Bic are an effect of the solution's neutral pH, as other factors of the prescription were constant. The Lac/ Bic solution is more biocompatible than Lac, reflecting short- and medium-term changes in the mesothelial cells, whose clinical significance has not yet been determined.