Ultrastructure of interstitial cells of Cajal in myenteric plexus of human colon

Abstract

The role of the interstitial cells of Cajal (ICC) associated with the myenteric plexus (ICC-MP) as regulators of the motility of the colonic external muscle remains unclear. Ultrastructural studies of myenteric interstitial cells are lacking in human colon. We therefore characterized the distinctive ultrastructure of these cells in the myenteric region of the colon by transmission electron microscopy of the region between the main muscle layers in all parts of the colon in unaffected areas of resected specimens from nine adult human patients. ICC-MP were similar in various colonic regions and had myoid features such as scattered caveolae, prominent intermediate filaments, and cytoplasmic dense bodies. We found characteristic dense membrane-associated bands with a patchy basal lamina, invaginating cellular protrusions (peg and socket junctions) between ICC and between ICC and muscle cells, and close contacts (<100 nm) between ICC and nerves. No gap junctions were observed. Fibroblast-like cells (FLC) were abundant showing well-developed secretory organelles, including coated vesicles, but lacked prominent intermediate filaments and caveolae. FLC had a patchy basal lamina, and peg and socket junctions were observed between them. Macrophage-like cells frequently occurred in close apposition with FLC and, more seldomly, with ICC-MP. The ultrastructure of ICC and FLC in the myenteric region of the human colon thus differs characteristically, but significant overlaps in the ultrastructure between ICC and FLC might complicate any interpretation in pathological ultrastructural studies of the human colonic muscle layer.

Characterization of Simultaneous Pressure Waves as Biomarkers for Colonic Motility Assessed by High-Resolution Colonic Manometry

“…Rabbit colon experiments have shown us that the SPW is generated by fast propagating contractions which are myogenic and likely controlled by interstitial cells of Cajal associated with the myenteric plexus (ICC-MP) ( Lentle et al, 2008 ) but the organization of these fast propagating contractions into rhythmic clusters is neurogenic ( Chen et al, 2016 ). The situation may be the same in the human colon which has a rich network of ICC-MP ( Rumessen et al, 2009 ) and fast propagation can easily be facilitated by an ICC network ( Wei et al, 2017 ). The SPW that is initiated by a meal or rectal stimulation will have an extrinsic neural origin and the progression along the colon will involve the enteric nervous system and may involve ICC networks.…”

Imaging features of primary anorectal gastrointestinal stromal tumors with clinical and pathologic correlation

“…Although GISTs are the most common malignant mesenchymal neoplasms of the gastrointestinal tract, anorectal GISTs are rare. GISTs are thought to derive from the interstitial cells of Cajal or a precursor cell [ 3 , 4 ] , which in the rectum form a network surrounding the autonomic nerves of the Auerbach (myenteric) plexus and are distributed within the inner and outer layer of the muscularis propria [ 14 ] . GISTs typically arise in the bowel wall and exhibit an expansile growth pattern.…”

Interstitial cells of Cajal and human colon motility in health and disease

“…Thuneberg (2) and Faussone-Pellegrini et al (3) introduced physiologists and clinicians to the importance of ICC as pacemaker cells, and it was Thuneberg's laboratory with Juri Rumessen that first showed us ICC in the human colon (4,5). ICC have features of smooth muscle cells and fibroblast-like cells, and knowledge of ICC location and contact with other cells is often essential for its positive ultrastructural identification.…”