A comparative study of the structure of human and murine greater omentum

Abstract

In humans, the greater omentum is a fatty peritoneal fold that extends from the greater curvature of the stomach to cover most abdominal organs. It performs many functions, which include acting as a reservoir of resident peritoneal inflammatory cells, a storage site for lipid, and a regulator of fluid exchange in and out of the peritoneal cavity. Most importantly, the omentum readily adheres to areas of inflammation and peritoneal damage, often leading to adhesion formation. Despite its clinical importance, the omentum remains an understudied organ, and discrepancies exist as to its exact morphology. This study uses a combination of phase contrast microscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM) to elucidate the structure of the greater omentum of both human and mouse and determine whether it possesses a typical surface mesothelial cell lining similar to other serosa. Results indicated that both human and murine omenta were of similar structure and composed of two distinct types of tissue, one adipose-rich and the other translucent and membranous. The adipose-rich regions were well-vascularised and covered by a continuous mesothelial cell layer except at the sites of milky spots. In contrast, translucent areas were poorly vascularised and contained numerous fenestrations of varying size. The possible function and developmental origin of these gaps is unclear; however, their role in promoting omental adhesion formation and in the successful use of omental graft material is discussed.

Use of a novel 3D culture model to elucidate the role of mesothelial cells, fibroblasts and extra‐cellular matrices on adhesion and invasion of ovarian cancer cells to the omentum

“…In addition, the mouse omentum is anatomically adjacent to the pancreas and has a different histologic appearance than human omentum. 28 Coculture models also have limitations, since they involve the interaction of ovarian cancer cells with only 1 ECM or 1 stromal cell type, which is often taken from a human site other than the omentum (e.g. foreskin fibroblasts) or from a different species.…”

Lymphocytes in the Peritoneum Home to the Omentum and Are Activated by Resident Dendritic Cells

“…Among the intraabdominal adipose tissues, the greater omentum is unique because it is thought to function in peritoneal surveillance and as an access route for blood leukocytes entering the resting (1, 2) and inflamed (3) peritoneal cavity (PC). 3 Murine and human greater omenta share many microanatomical features despite some differences in gross appearance (4). The greater omentum is a mobile structure that moves with gut peristalsis in the small free volume of peritoneal fluid.…”

A comparative study of local defense spots within the peritoneal cavity in Japanese quails,Coturnix coturnix japonica(Galliformes, Phasianidae) and Wistar rats,Rattus norvegicus(Rodentia, Muridae)

“…Cell composition and functions of local defense spots in the peritoneal cavity have been studied in rats (Wijffels et al 1992;Van Vught et al 1996;Di Paolo & Sacchi 2000;Hekking et al 2001), mice (Dux 1986;Cranshaw & Leak 1990;Wijffels et al 1992) and humans (Shimotsuma et al 1991;Shimotsuma et al 1993;Takemori et al 1995;Krist et al 1997;Wilkosz et al 2005). However, to the best of our knowledge there is no published data on the local defense foci of the peritoneal cavity in birds.…”