Interstitial cells of Cajal (ICC) in equine colic: an immunohistochemical study of horses with obstructive disorders of the small and large intestines

Abstract

SummaryReasons for performing study: The gastrointestinal pacemaker cells, the interstitial cells of Cajal (ICC), have been implicated in several human gastrointestinal dysmotility syndromes. Recently, the involvement of these cells in equine gastrointestinal diseases has been investigated in cases of equine grass sickness where a significant reduction in ICC density was observed. Objective: To investigate ICC density in equine obstructive gastrointestinal disorders using immunohistochemical labelling methods. Methods: Intestinal samples were analysed from 44 horses undergoing exploratory surgery for colic and from 11 control animals subjected to euthanasia for conditions not related to the gastrointestinal tract. Immunohistochemical labelling of ICC was carried out using an anti-c-Kit antibody. Two independent observers assessed ICC density using a semiquantitative grading system. Results: There was a significant reduction in ICC density in horses with large colon disorders compared to the controls (P<0.01). Horses with strangulating lesions of the small intestine showed no difference when compared to the controls. Conclusions: There was a reduction in ICC density in horses with large intestinal disorders. Potential relevance: The reduction in ICC density may be associated with the clinical findings as well as recurrent colic episodes observed in a number of these cases. This immunohistochemical study provides a basis for future functional electrophysiological investigations to determine the precise effect of ICC reduction on equine intestinal motility.

Expression of PGP 9.5 by Enteric Neurons in Horses and Donkeys with and without Intestinal Disease

“…Conversely, in the horse study of Pavone et al (2012), it was suggested that the enteric nervous system and ICC changes observed may have been secondary to the colic episodes. Fintl et al (2004) suggested that the ICC changes in horse large intestinal obstructive disorders may have been a possible cause rather than effect of the colic episodes.…”

“…Horses with chronic obstructive disorders of the large colon or recurrent caecal impactions have been shown to have reduced densities of neurons in the large colon or caecum (Schusser and White, 1997;Schusser et al, 2000). Additionally, a reduction in ICC density has been demonstrated in the pelvic flexure of horses with large intestinal obstructive disorders, suggesting a possible involvement of ICC in equine intestinal dysmotility (Fintl et al, 2004). Recently, a reduction in enteric neuronal activity and ICC immunoreactivity in cases of colic in horses has been reported (Pavone et al, 2012).…”

“…The animals in this study included material from 39 horses from previous immunohistochemical and molecular studies of ICC (Fintl et al, 2004(Fintl et al, , 2010b. Samples from six additional horses were included.…”

“…A semiquantitative grading system, as described for previous equine ICC studies (Hudson et al, 2001;Fintl et al, 2004), was used and modified for this study. The grades given were based on the scrutiny of four adjacent 10 μm tissue sections from each sample from each animal.…”

In vitro analysed effects of two different in vivo administered lidocaine dosageson the equine jejunal smooth muscle challenged by an ischemia-reperfusion-injury-model (IRIM)

“…With TTX treated equine jejunal muscle strips show spontaneous contractions (basal contractility) mediated by the electric pacemaker function of ICCs (Takaki 2003, Fintl et al 2004) without any neuronal participation. These spontaneous contractions can be defined by amplitude (isometric force of contraction, mN) and by frequency (peaks/min).…”