Spatial differentiation of the intestinal epithelium: analysis of enteroendocrine cells containing immunoreactive serotonin, secretin, and substance P in normal and transgenic mice.

Abstract

The mammalian intestinal epithelium undergoes continuous and rapid renewal of its four principal terminally differentiated cell types. These cells arise from multipotent stem cells located at or near the base of the crypts of Lieberkuhn. The differentiation process is precisely organized along two spatial dimensions (axes)-from the crypt to the villus tip and from the duodenum to the colon. The enteroendocrine cell population provides a sensitive marker of the intestine's topologic differentiation. At least 15 different regionally distributed subsets have been described based on their principal neuroendocrine products. We have used immunocytochemical methods to characterize the spatial relationships of the serotonin-, secretin-, and substance P-containing enteroendocrine cell subsets in normal adult C57BL/6J X LT/Sv mice as well as in transgenic littermates that contain rat liver fatty acid-binding protein-human growth hormone fusion genes. Our results reveal precise spatial interrelationships between these populations and suggest a differentiation pathway that may involve the sequential expression of substance P, serotonin, and secretin.

Cell-specific expression of alpha 1-antitrypsin in human intestinal epithelium.

“…To be certain that the hybridization signal was specific for probe C, sequential sections of the same tissue were hybridized under identical conditions using "S-UTP-labeled sense probe C. Using the sense probe C, scattered grains were found over tissue and slide but no specific hybridization signal was ever found. (11)(12)(13). Sections were first immunostained for a particular antigen using the immunogold silver staining method.…”

Glucose sensing and signalling; regulation of intestinal glucose transport

“…Paneth cells, which secrete antimicrobial peptides, digestive enzymes and growth factors, complete their differentiation at the crypt base. The other three epithelial lineages differentiate during a highly organised upward migration from the crypt to the villus tip where they are extruded into the intestinal lumen (1,2) . This process takes about 2-3 d in most species (3)(4)(5) .…”

Studies with GIP/Ins cells indicate secretion by gut K cells is KATPchannel independent

“…ithelial cells that play important roles in regulating and integrating many aspects of gastrointestinal and whole animal physiology (1,32,48,52,57,66). Although they represent Ͻ1% of the intestinal epithelial cells, EE cells as a whole represent the largest endocrine organ in the body.…”