Remodelling of adipose tissue during experimental omental adhesion formation

Abstract

Abstract Background Peritoneal adhesions are fibrous bands of tissue connecting normally separated organs and frequently involve the fat-laden greater omentum. Remodelling of fibrin-rich exudate under reduced fibrinolytic conditions is thought to initiate adhesion formation following surgery. It is unclear whether adhesions that involve the omentum develop in a similar manner. To improve understanding of omental adhesion formation, adipose tissue distribution, cell proliferation and procollagen type I gene expression were investigated in a murine surgical model and in established omental adhesions from patients undergoing abdominal surgery. Methods Experimental murine omental adhesions and human omental adhesions were analysed for signs of tissue remodelling using histology, immunohistochemistry and in situ hybridization. Results Murine omental tissue showed intense inflammation and reduced adipose tissue 3–7 days after surgery, but increased cellularity and collagen production. Adipose tissue remodelling was reversible with increased adipose tissue and decreased cell proliferation and procollagen type I gene expression, shown by proliferating cell nuclear antigen immunolocalization and in situ hybridization respectively. Human omental adhesions were heterogeneous, with varying amounts of fibrotic and adipose-rich regions, although most displayed proliferating and collagen-producing cells. Conclusion Omental adhesions are not static scar tissue as traditionally thought, but undergo active adipose tissue remodelling over-time.