Review: Enteroendocrine cells: Neglected players in gastrointestinal disorders?

Abstract

Enteroendocrine cells (EEC) form the basis of the largest endocrine system in the body. They secrete multiple regulatory molecules which control physiological and homeostatic functions, particularly postprandial secretion and motility. Their key purpose is to act as sensors of luminal contents, either in a classical endocrine fashion, or by a paracrine effect on proximate cells, notably vagal afferent fibres. They also play a pivotal role in the control of food intake, and emerging data add roles in mucosal immunity and repair. We propose that EEC are fundamental in several gastrointestinal pathologies, notably Post-infectious Irritable Bowel Syndrome, infectious enteritis, and possibly inflammatory bowel disease. Further work is needed to fully illustrate the importance, detailed biology and therapeutic potential of these frequently overlooked cells.

Epithelial Cell Contributions to Intestinal Immunity

“…Like goblet cells and Paneth cells, enteroendocrine cells are specialized for secretion. They sense luminal contents, particularly nutrients, and secrete multiple regulatory factors such as gastric inhibitory peptide, glucagon-like peptide, and vasoactive intestinal peptide that regulate digestion, intestinal motility, and food intake (Moran, Leslie, Levison, Worthington, & McLaughlin, 2008). Although enteroendocrine cells are scattered throughout the intestine, taken together they constitute one of the largest endocrine systems in the body.…”

M Cells

“…Although as a group intestinal enteroendocrine cells can secrete a wide variety of peptides, individual enteroendocrine cells often predominantly produce a single peptide. A subset of enteroendocrine cells also produces biogenic amines such as serotonin (Moran et al, 2008).…”

Development and Physiology of the Intestinal Mucosal Defense

“…Paneth cells release lysozyme and antimicrobial peptides (AMPs), which form a protective chemical barrier limiting exposure of the intestinal epithelium to intestinal microbiota and antigens (Schulz and Pabst, 2013; see Chapter 16). Enteroendocrine cells (EECs) are scattered as single cells throughout the intestinal tract (Moran et al, 2008). EECs together with goblet cells and Paneth cells constitute the secretory cell types in the small intestine.…”

“…These cells play an important role in the control of food intake. Recent evidence indicates that EECs also play roles in mucosal immunity and repair (Moran et al, 2008). M cells, which are characterized by their flattened apical surfaces and lack of a mucus layer, are specialized epithelial cells that reside predominantly in PPs (see Chapter 13).…”