title: Ultrastructure of interstitial cells in subserosa of human colon.
abstract: We studied the ultrastructure of interstitial cells in the subserosal/adventitial layer in human colon. An interstitial cell type with an ultrastructure intermediate between fibroblast-like cells (FLC) and interstitial cells of Cajal was identified (IC-SS). IC-SS had thin and flattened branching processes, most densely arranged close to the longitudinal muscle cells. Caveolae, bundles of intermediate filaments and membrane-associated dense bands, often with a patchy basal lamina, were characteristic. Secretory organelles (granular endoplasmic reticulum, smooth endoplasmic reticulum, Golgi, coated vesicles) were prominent. The IC-SS ultrastructure was different from that of FLC in the longitudinal layer, which had no caveolae and fewer intermediate filaments. Peg-and-socket junctions between IC-SS and between IC-SS and muscle cells were present, and IC-SS processes had close, selective appositions to muscle cells. Gap junctions were not observed. Small nerve bundles were abundant, but close contacts (<100 nm) between IC-SS or muscle cells and nerves were inconspicuous. Close appositions between IC-SS and mast cells were present; close relations to macrophages were not observed. The myoid features of IC-SS are thus more pronounced in comparison with FLC of other locations in the gastrointestinal muscle. The organization and ultrastructure may suggest a regulatory nature of IC-SS on the colonic muscle layers.
authors: Research Department and Department of Gastroenterology F, Gentofte Hospital, DK–2900 Hellerup, Denmark. juru @ geh.regionh.dk
authors: Jüri Johannes
authors: JJ
authors: Rumessen
authors: Jean-Marie
authors: JM
authors: Vanderwinden
authors: Alastair
authors: A
authors: Hansen
authors: Thomas
authors: T
authors: Horn
mesh_terms: D003106:Colon / Q000166:cytology / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D056885:Interstitial Cells of Cajal / Q000648:ultrastructure*; D008297:Male; D008875:Middle Aged; D009130:Muscle, Smooth / Q000166:cytology / Q000648:ultrastructure*