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Recently, in the Mailing List of the Italian Society of Nephrology (ML-SIN), a message asking for opinions on the diagnosis and treatment of peritoneal sclerosis gave rise to an extensive debate on this interesting clinical topic. The discussion evidenced significant differences both in the reported onset of clinical manifestations, emphasizing the difficulty in obtaining a definite early diagnosis, and in therapy approaches. Occasionally, this is limited to medical treatment, but surgery, although burdened with elevated complexity and high mortality rates due to post-operative complications, is usually advocated for intestinal obstruction. This is the second issue reserved for the review of the ML-SIN concerning this topic, following that dedicated to definition, etiology, pathology and clinical characteristics. In this section, two expert colleagues complete the analysis of the different aspects of peritoneal sclerosis, discussing the therapy and the prevention of this serious complication of peritoneal dialysis.

Hemodiafiltration reinfusion (HFR) treatment is a dialysis technique that uses the endogenous reinfusion fluid and performs, simultaneously and separately, the three mechanisms of extracorporal depuration: diffusion, convection and adsorption. This study aimed to evaluate clinical and biochemical data of a group of six patients submitted to a dialytic HFR method for6 months.Six patients with a mean age of 53.8 +/- 11 yrs (five males, one female), treated with standard bicarbonate dialysis for a mean of 79.2 months, underwent HFR for a mean period of 14.9 +/- 6 months. Filters used were: a) in all patients polysulfone with 0.7 m2 of surface for the convection; b) polysulfone with 1.7 m2 in one patient, and modified cellulose with 2.0 m2 in five patients for diffusion; c) hydrophobic interaction resin and uncovered mineral carbon 240 mL for the adsorption. For all patients dialysis duration was 240 min and the amount of reinfusion fluid was 2.5 L/h as a mean, calculated according to blood flow and hematocrit (Hct), keeping a filtration fraction22%. We evaluated, at different times, the following parameters: a) patient weight; b) Hct and erythropoietin (EPO) doses; c) parathyroid hormone (PTH); d) phosphatemia and doses of administered vitamin D; e) homocysteine (Hcy) and Beta2-microglobulin (Beta2-m); f) and albuminemia and transferrinemia as nutritional parameters.We observed an increase in Hct, with a reduction in EPO dosage, and an increase in albumin and transferrin levels, an improvement in nutritional indexes and in patient well-being. The mild increase in Hct with the same EPO dose was present in spite of a switch to intravenous (i.v.) administration from subcutaneous administration. There was low morbidity and only one hospitalization due to an infectious episode.HFR allows an amino acid saving and pro-inflammatory middle molecule removal, resulting in a better clinical situation for progressively critical uremic patients.

Peritoneal dialysis (PD) impairs both structure and function of the peritoneal membrane (PM). Aim of the study is to examine the relationship among dialytic, histological and functional parameters in PD patients.Thirty-one PD patients were submitted to peritoneal biopsy (PB) during catheter removal for malfunction or after dropping out of the treatment. For each patient PM transport was evaluated by the last peritoneal equilibration test (PET) prior to PB. Each daily glucose load was calculated. PB was performed at a distance of at least 5 cm from the catheter insertion point. The tissues were promptly embedded in formalin and stained for histological and immunohistochemical studies.1) Patients with mesothelial impairment had longer treatment time. 2) Patients presenting submesothelial sclerosis (SS) and those with impairment of submesothelial basement membrane and subendothelial vascular membrane (SVM) were submitted to larger daily glucose loads. 3) High transporters were exposed to larger daily glucose loads and presented an SS thickness greater than 50 micron more frequently than medium-high transporters. 4) Mesothelial loss was correlated with SS and vascular alterations. 5) SS and vascular injuries were related to each other and not to inflammatory infiltrate.Our study suggests that PD length seems to be mainly involved in mesothelial impairment; glucose load appears to damage mainly the submesothelial layer; SS is not a constant event in PD patients and in itself does not seem to be a decisive factor in PD drop out.

Peritoneal membrane changes in continuous ambulatory peritoneal dialysis (CAPD) patients have been widely described but poorly classified. Our aim was to identify the morphological changes occurring after CAPD treatment. To this end, 17 biopsies of parietal peritoneum (1 cm in diameter) were withdrawn at least 5 cm from the catheter entry hole and stained with Van Gieson, hematoxylin-eosin, trichrome, and some immunohistochemical stains: keratin, vimentin, CD34, CD20, CD4, CD8, desmin, and collagen IV. The morphology of mesothelium, vessels, and basement membrane (BM) of mesothelium and vessels, the presence of inflammatory cells, fibrin, and calcifications, and the distribution and thickness of submesothelial tissue were evaluated. Patients were divided into three groups according to the thickness of the sclerotic band replacing mesothelium: group 1, band up to 40 microns; group 2, band less than 40 microns; group 3, no sclerotic band. The main histopathological alterations noted were: loss of mesothelium; sclerotic alteration of vessels or duplication of BM; presence of myofibroblasts; and presence of inflammatory cells (sparse, focal, or perivascular), mainly represented by macrophages and CD4+ lymphocytes. No significant qualitative differences were observed between the three groups. In conclusion, the variable histological changes in peritoneal membrane suggest a routine peritoneal biopsy in any surgical procedure to better understand pathological changes in the course of CAPD treatment.