Platelet-derived growth factor receptor-β expression in human peritoneum.

Area of Science:

• Nephrology
• Pathology
• Cell Biology

Background:

• Peritoneal fibrosis and encapsulating peritoneal sclerosis (EPS) are common in patients undergoing peritoneal dialysis (PD).
• Podoplanin-positive myofibroblasts have been identified in EPS, and platelet-derived growth factors (PDGFs) may contribute to peritoneal fibrotic responses.
• Platelet-derived growth factor receptor-β (PDGFRβ) is a marker for pericytes, suggesting a potential role in peritoneal fibrogenesis.

Purpose of the Study:

• To investigate the presence and characteristics of PDGFRβ in the human peritoneum.
• To determine the relationship between PDGFRβ, myofibroblasts, and pericytes in normal and pathological conditions of the peritoneum.

Main Methods:

• Retrospective analysis of peritoneal biopsies from patients with EPS, patients on PD without EPS, normal peritoneum, and uremic patients.
• Immunohistochemical staining for PDGFRβ, smooth muscle actin (SMA), and podoplanin.
• Semiquantitative scoring by blinded observers.

Main Results:

• PDGFRβ was expressed in arterial walls across all groups.
• Normal peritoneum showed PDGFRβ-positive cells that were SMA-negative.
• Patients on PD exhibited increased PDGFRβ and SMA co-expression.
• In EPS, most podoplanin-positive myofibroblasts also expressed PDGFRβ.
• Podoplanin was restricted to lymphatic vessels in normal and PD patients without EPS.

Conclusions:

• Podoplanin-positive myofibroblasts in EPS express PDGFRβ, suggesting a potential pericyte origin.
• PDGFRβ-positive myofibroblasts may play a significant role in the pathogenesis of EPS.
• PDGFRβ emerges as a potential therapeutic target for managing encapsulating peritoneal sclerosis.