title: Perivascular Interstitial Cells of Cajal in Human Colon.
abstract: OBJECTIVE
  Interstitial cells of Cajal (ICC) closely associate with nerves and smooth muscles to modulate gut motility. In the ICC microenvironment, although the circulating hormones/factors have been shown to influence ICC activities, the association between ICC and microvessels in the gut wall has not been described. We applied three-dimensional (3D) vascular histology with c-kit staining to identify the perivascular ICC and characterize their morphologic and population features in the human colon wall.
  
  
  METHODS
  Full-thickness colons were obtained from colectomies performed for colorectal cancer. We targeted the colon wall away from the tumor site. Confocal microscopy with optical clearing (use of immersion solution to reduce scattering in optical imaging) was performed to simultaneously reveal the ICC and vascular networks in space. 3D image rendering and projection were digitally conducted to illustrate the ICC-vessel contact patterns.
  
  
  RESULTS
  Perivascular ICC were identified in the submucosal border, myenteric plexus, and circular and longitudinal muscles via high-definition 3D microscopy. Through in-depth image projection, we specified two contact patterns-the intimate cell body-to-vessel contact (type I, 18% of ICC in circular muscle) and the long-distance process-to-vessel contact (type II, 16%)-to classify perivascular ICC. Particularly, type I perivascular ICC were detected with elevated c-kit staining levels and were routinely found in clusters, making them readily distinguishable from other ICC in the network.
  
  
  CONCLUSIONS
  We propose a new subclass of ICC that closely associates with microvessels in the human colon. Our finding suggests a functional relationship between these mural ICC and microvessels based on the morphologic proximity.
authors.affiliation: Connectomics Research Center, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Yuan-An
authors.initials: YA
authors.lastname: Liu
authors.affiliation: Department of Surgery, Cheng Ching General Hospital, Chung Kang Branch, Taichung, Taiwan.
authors.forename: Yuan-Chiang
authors.initials: YC
authors.lastname: Chung
authors.affiliation: Division of Colorectal Surgery, National Taiwan University Hospital, Hsinchu Branch, Hsinchu, Taiwan.
authors.forename: Ming-Yin
authors.initials: MY
authors.lastname: Shen
authors.affiliation: Department of Pathology, Miaoli General Hospital, Miaoli, Taiwan.
authors.forename: Shien-Tung
authors.initials: ST
authors.lastname: Pan
authors.affiliation: Department of Pathology, National Taiwan University Hospital, Hsinchu Branch, Hsinchu, Taiwan.
authors.forename: Chun-Wei
authors.initials: CW
authors.lastname: Kuo
authors.affiliation: Connectomics Research Center, National Tsing Hua University, Hsinchu, Taiwan; Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Shih-Jung
authors.initials: SJ
authors.lastname: Peng
authors.affiliation: Division of Gastroenterology and Hepatology, Johns Hopkins University School of Medicine, Baltimore, Maryland.
authors.forename: Pankaj J
authors.initials: PJ
authors.lastname: Pasricha
authors.affiliation: Connectomics Research Center, National Tsing Hua University, Hsinchu, Taiwan; Department of Medical Science, National Tsing Hua University, Hsinchu, Taiwan.
authors.forename: Shiue-Cheng
authors.initials: SC
authors.lastname: Tang
keywords: 3D Histology; 3D, three-dimensional; 5-HT, serotonin; ICC; ICC, interstitial cells of Cajal; ICC-CM, ICC in the circular muscle; ICC-LM, ICC in the longitudinal muscle; ICC-MY, ICC around the myenteric plexus; ICC-SM, ICC at the submucosal border; Mural Cells; NA, numerical aperture; PBS, phosphate-buffered saline; SCF, stem cell factor; c-kit