title: Morphological Retrospective Study of Peritoneal Biopsies from Patients with Encapsulating Peritoneal Sclerosis: Underestimated Role of Adipocytes as New Fibroblasts Lineage?
abstract: Background. Encapsulating peritoneal sclerosis (EPS) is a rare but serious complication of peritoneal dialysis (PD). Besides the endothelial-to-mesenchymal transition (EMT), recently peritoneal adipocytes emerged as a potential source of fibrosis. We performed immunohistochemistry to approach EMT and to localize peritoneal adipocytes in peritoneal biopsies from PD-related EPS patients. Material and Methods. We investigated tissue expression of podoplanin, cytokeratin AE1/AE3 (mesothelium), calretinin (adipocytes), alpha-smooth muscle actin [α-SMA] (mesenchymal cells), interstitial mononuclear cell inflammation, and neoangiogenesis (CD3, CD4, CD8, CD20, CD68, and CD31 immunostainings, resp.). Results. Three patients (1 man/2 women; 17, 64, and 39 years old, resp.) developed EPS after 21, 90, and 164 months of PD therapy. In patients with EPS, we observed (1) loss of AE1/AE3 cytokeratin+ mesothelial cells without any evidence of migration into the interstitium, (2) disappearance of adipose tissue, (3) diffuse infiltration of calretinin+ cells in the areas of submesothelial fibrosis with a huge number of α-SMA and calretinin+ fusiform cells, and (4) increased vascular density. Conclusion. We report that the involvement of EMT in peritoneal fibrosis is difficult to demonstrate and that the calretinin+ adipocytes might be an underestimated component and a new source of myofibroblasts in peritoneal remodeling during PD-related EPS.
authors.affiliation: Laboratory of Experimental Nephrology, Department of Biochemistry, Faculty of Medicine, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Monika
authors.initials: M
authors.lastname: Tooulou
authors.affiliation: Department of Pathology, Cliniques Universitaires de Bruxelles (CUB), Erasme Hospital, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Pieter
authors.initials: P
authors.lastname: Demetter
authors.affiliation: Department of Nephrology, Cliniques Universitaires de Bruxelles (CUB), Erasme Hospital, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Anwar
authors.initials: A
authors.lastname: Hamade
authors.affiliation: Department of Radiology, Cliniques Universitaires de Bruxelles (CUB), Erasme Hospital, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Caroline
authors.initials: C
authors.lastname: Keyzer
authors.affiliation: Laboratory of Experimental Nephrology, Department of Biochemistry, Faculty of Medicine, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium ; Department of Nephrology, Cliniques Universitaires de Bruxelles (CUB), Erasme Hospital, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Joëlle L
authors.initials: JL
authors.lastname: Nortier
authors.affiliation: Laboratory of Experimental Nephrology, Department of Biochemistry, Faculty of Medicine, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium ; Department of Nephrology, Cliniques Universitaires de Bruxelles (CUB), Erasme Hospital, Université Libre de Bruxelles (ULB), 1070 Brussels, Belgium.
authors.forename: Agnieszka A
authors.initials: AA
authors.lastname: Pozdzik