Morphological changes of the peritoneal membrane in patients with long-term dialysis.

Morphological alterations of peritoneum in chronically dialyzed patients involve fibrosis and angiogenesis as pathogenic mechanisms. The aim of this retrospective study was to evaluate morphological changes of peritoneum in chronic peritoneal dialysis (PD) at 4, 8, 12, and 14 years. Peritoneal changes were investigated in 110 patients with end stage renal failure, which were included in a PD program. Intraoperative biopsies were grouped in four study Groups (A: 1-48 months, B: 49-96 months, C: 97-144 months, and D: 145-168 months), and were processed histologically and stereologically. Mesothelial denudation was found in percentage volumes of 5.49% - Group A, 16.10% - Group B, 16.68% - Group C and 19.88% - Group D. Reduplication of the basement membrane was observed in patients with over five years of PD. Interstitial stromal fibrosis recorded percentage volumes of 25.49% (Group A), 26.10% (Group B), 35.85% (Group C) and 56.63% for the patient with 14 years of PD. Subendothelial hyalinizing vasculopathy was recorded in percentage volumes of 2.22%, 6.63%, 9.16% up to 9.20%. Vascular permeability reduction was recorded as decreasing percentage volumes from 22.59% to 12.81%, 7.77% and 7.37%. Perivascular inflammation was marked in the serosa of the patients in Group A (4.55%). Calcifications recorded percentage volumes of 1.63% at eight years, 3.74% at 12 years and 4.03% at 14 years of PD. Peritoneal morphological changes appear at 3-4 years of PD and progressively aggravate with long-term PD.