Interstitial Cells Of Cajal In Tissues Research Articles

Immunoreactivity for Ano1 detects depletion of Kit-positive interstitial cells of Cajal in patients with slow transit constipation

Depletion of interstitial cells of Cajal (ICC) is associated with several gastrointestinal (GI) motility disorders. Changes in ICC networks are usually detected by immunolabeling for the receptor tyrosine kinase Kit. Ano1 (DOG1 or TMEM16A) was recently described as a marker of ICC in GI tract. Our aim was to determine whether Ano1 immunoreactivity can be used as a reliable marker for ICC in tissues from patients with motility disorders. Four tissues from patients with normal ICC numbers and four tissues from patients with slow transit constipation and loss of Kit-positive ICC were studied. Interstitial cells of Cajal were detected by double labeling using antisera to Kit and Ano1. Both the processes and cell bodies of ICC in tissue from controls and slow transit constipation were immunoreactive for Ano1. There was a near complete overlap between Kit and Ano1 immunoreactivity. Tissues from patients with slow transit constipation contained significantly fewer Ano1-positive ICC than control tissues. The numbers of ICC identified by Ano1 and Kit immunoreactivity were nearly identical across the range of ICC numbers from an average of 1.64 to 7.05 cells per field and correlated with an R(2) value of 0.99. Ano1 is a reliable and sensitive marker for detecting changes in ICC networks in humans. Labeling with antibodies selective for Ano1 reproducibly detects depletion of Kit-positive ICC in tissues from patients with slow transit constipation.

The search for the origin of rhythmicity in intestinal contraction; from tissue to single cells.

More than a century ago, rhythmic propulsive contractile activity was observed in the intestine after blockade of nerve conduction, thus demonstrating a form of peristalsis that appeared to be under myogenic control. During this century, light and electron microscopic investigations provided the hypothesis that interstitial cells of Cajal (ICC) could be the cells of origin for this rhythmicity. In recent years, physiological studies demonstrated a link between the presence of electrical slow wave activity and the presence of ICC. The recognition that the ICC cell membrane harbours the Kit protein sparked rapid advancement in ICC research, and has been essential in the identification of ICC in tissue and in culture through Kit immunohistochemistry and kit mRNA reverse transcriptase polymerase chain reaction (RT-PCR). With these techniques, electrophysiology was carried out on positively identified single ICC in culture. These methods revealed that single ICC generate spontaneous rhythmic inward currents and slow waves in membrane potential, thus providing strong evidence that ICC generate the electrical pacemaker activity for the gut musculature.