Background: Chronic peritoneal dialysis may eventually result in peritoneal fibrosis, which progressively reduces dialytic efficacy. Although the pathogenesis has not been elucidated, it has been proposed that transforming growth factor beta-1 (TGF beta 1) plays a central role in the onset of peritoneal fibrosis.
Methods: Rats were divided into three groups and given saline, hypertonic peritoneal dialysis solution alone, a hypertonic peritoneal dialysis solution plus octreotide intraperitoneally. After four weeks, a one-hour peritoneal equilibration test was done. Dialysate-to-plasma urea ratio, glucose reabsorption, ultrafiltration volume and levels of dialysate protein, TGF beta 1 and cancer antigen 125 (CA 125) were determined. The peritoneal membrane was examined histologically by light microscopy.
Results: Compared to the saline group, peritoneal function tests (ultrafiltration volume 6 (5-7) vs 0.0 ml, dialysate-to-plasma urea ratio 0.51 vs 0.76, glucose reabsorption 0.54 vs 0.40 and morphology (thickness 4.5 vs 75.5 microns) were dramatically deranged in hypertonic peritoneal dialysis solution-treated rats, which also had a higher level of TGF beta 1 and undetectable CA 125. In contrast, in hypertonic peritoneal dialysis solution plus octreotide rats' peritoneal function was protected (ultrafiltration volume 3 mL, dialysate-to-plasma urea 0.60, glucose reabsorption 0.51) but peritoneal thickening (37.7 microns) was not so markedly reduced although the production of TGF beta 1 was significantly inhibited.
Conclusion: These data show that by inhibiting the production of TGF beta 1, octreotide can preserve peritoneal function and remodeling of the mesothelial cell. Although the production of TGF beta 1 was significantly inhibited, peritoneal thickening cannot be completely prevented.