Morphological Retrospective Study of Peritoneal Biopsies from Patients with Encapsulating Peritoneal Sclerosis: Underestimated Role of Adipocytes as New Fibroblasts Lineage?

Figure 5

Representative photomicrographs demonstrating histopathological data of mesenchymal markers expression in parietal peritoneal tissues biopsy using immunostaining of vimentin (a–d) and alpha-smooth muscle actin (α-SMA) (e–h). Positive control of immunostainings for used antibodies (internal controls) (a, e), control: normal peritoneum (b, f), case of acute peritonitis (control 3; c and g), and case  1 of encapsulating peritoneal sclerosis (EPS) (d and h). (a, e) Normal peritoneum, expression of vimentin (→) limited to few interstitial cells and of α-SMA expression to vascular walls. (c, g) Acute peritonitis: interstitial vimentin+ cells, lack of expression of vimentin in mesothelial cell layer; α-SMA found only in the vessels. (d, h) Case of encapsulating peritoneal sclerosis (EPS): absence of expression of both markers in the mesothelial cell layer. Note diffuse accumulation of vimentin+ cells identifying interstitial mesenchymal cells and α-SMA immunostaining of numerous interstitial cells entrapped in the fibrotic areas reflecting the presence of myofibroblasts. Immunoperoxidase staining counterstained with haematoxylin. Original magnification: (a–g) ×20. (h) ×4.