Korean Journal of Nephrology 1995;14(2):161-167.

(Dipeptide -Based Solution for Peritoneal Dialysis : Investigations with a Rat Model)

Min Sun Park , Jse Won Lee , Jae Hak Joo

Abstract

Objectives: To investigate the potential effect of dipeptides as osmotic agents, the peritoneal fluid and solute transport characterisitcs were evaluated during peritoneal dia- lysis using dipeptide-based dialysis solution in rat Methods: A 4 hour single peritoneal dialysis was performed in 12 normal Sprague- Dawley rats. The dipeptide solution(DPS) contained two different di-peptides (AB and AC) containing 3 different amino acids(A, B and C). The total molar concentration of the solution was 169 mmol/l(n=6). The electrolyte concentrations were sodium 132, calcium 1.75, magnesium 0.75, chloride 102, all in mmol/I. Bicarbonate 35 mmol/l was used as a buffer in DPS. The pH of DPS was 7.4. The glucose-based dialysis solution(GBS, Dianeal 3.86% solution containing 3.86 g/1 of anhydrous glucose) was used to provide control values(n=6). Sodium hydroxide 5 mmol/l was added into GBS to achieve the pH value of 7A and therefore the initial dialysate sodium concentration was 136mmol/1. The calculated osrnolality was 439 mmol/kg in DPS and 486 mmol/kg in GBS. Infusion volume was 30 ml. Intraperitoneal dialysate volume was estimated from the dilution of volume marker, 'I human serum albumin(RISA), with corrections for the elimination of RISA from the peritoneal cavity(Kz, ml/min) and sample volume. The diffusive transport coefficient(Kf3p) and the sieving coefficient(S) were estimated using modified Babb- Randerson-Farrell model. Results: The intraperitoneal volume over time curve and the maximum intraperitoneal volume(Vp .,) were lower with DPS than with GBS. The peritoneal fluid reabsorption rate estimated by the volume marker elimination rate Kz, was significantly lower with DPS than with GBS. The intraperitoneal net volume change between 180 min and 240 min (Qv>w .w) was significantly lower with DPS than with GBS. During dialysis with DPS the intraperitoneal concentrations of dipepitdes(AB and AC) decreased and the three amino acids, A, B and C, derived from the two dipeptides rapidly in the peritoneal cavity. At the end of a 4hr dialysis, the plasma concentrations of the three amino acids, A, B and C, increased rapidly and reached the concentrations of 51.8, 5.6 and 1.5 times higher thand their baseline values, respectively, while dipeptides were not traced in plasma. Kpp for urea and glucose with DPS were significantly lower than those values with GBS. Conclusion: It is concluded that dipeptides can be good alternative osmotic agents that provides prolonged ultrafiltration and nutrient amino acids from dialysate. However, the use of two dipeptides containing one common amino acid sholuld be avoided to pre- vent unphysilologically high concentration of certain arnino acid in plama, The future study on the altered peritoneal transport charateristics for urea and glucose with DPS is needed.