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Igf1r+/CD34+ immature ICC are putative adult progenitor cells, identified ultrastructurally as fibroblast-like ICC in Ws/Ws rat colon.

Wang XY, Albertí E, White EJ, Mikkelsen HB, Larsen JO, Jiménez M, Huizinga JD - J. Cell. Mol. Med. (2009)

Bottom Line: A significantly higher number of Igf1r(+)/CD34(+) cells were found in Ws/Ws compared to wild-type rat colons.Immunohistochemistry revealed a reduction of neurons positive for neuronal nitric oxide synthase.The reduction in nitrergic innervation associated with the Ws mutation may be the result of a reduction in nitrergic neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada.

ABSTRACT
The colon of Ws/Ws mutant rats shows impairment of pacemaker activity and altered inhibitory neurotransmission. The present study set out to find structural correlates to these findings to resolve mechanisms. In the colon of Ws/Ws rats, interstitial cells of Cajal associated with Auerbach's plexus (ICC-AP) were significantly decreased and ICC located at the submuscular plexus and intramuscular ICC were rarely observed based on immunohistochemistry and electron microscopy. Ultrastructural investigations revealed that there was no overall loss of all types of interstitial cells combined. Where loss of ICC was observed, a marked increase in fibroblast-like ICC (FL-ICC) was found at the level of AP. Immunoelectron microscopy proved FL-ICC to be c-Kit(-) but gap junction coupled to each other and to c-Kit(+) ICC; they were associated with enteric nerves and occupied space normally occupied by ICC in the wild-type rat colon, suggesting them to be immature ICC. In addition, a marked increase in immunoreactivity for insulin-like growth factor 1 receptor (Igf1r) occurred, co-localized with CD34 but not with c-Kit. A significantly higher number of Igf1r(+)/CD34(+) cells were found in Ws/Ws compared to wild-type rat colons. These CD34(+)/Igf1r(+) cells in the Ws/Ws colon occupied the same space as FL-ICC. Hence we propose that a subset of immature ICC (FL-ICC) consists of adult progenitor cells. Immunohistochemistry revealed a reduction of neurons positive for neuronal nitric oxide synthase. The functional capabilities of the immature ICC and the regenerative capabilities of the adult progenitor cells need further study. The morphological features described here show that the loss of pacemaker activity is not associated with failure to develop a network of interstitial cells around AP but a failure to develop this network into fully functional pacemaker cells. The reduction in nitrergic innervation associated with the Ws mutation may be the result of a reduction in nitrergic neurons.

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Immunohistochemistry (frozen sections) showing c-Kit+ cells in the proximal (a and b), mid (c and d) and distal (e and f) colon from wild-type (a, c and e) and Ws/Ws (b, d and f) rats. In wild-type rats (a, c and e) a high density of c-Kit+ cells is observed at the level of the AP surrounding the ganglia, at the submucosal (SubM) border and within both circular (CM) and longitudinal muscle (LM) layers. Small arrows in figure a show ICC-AP connected with ICC-IM in the circular muscle layer and small arrows in (c) indicate the ICC-AP protruding into the myenteric ganglia. Mutant rats only showed a few c-Kit+ cells at the AP region. Scale bar is for (a)–(f).
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fig01: Immunohistochemistry (frozen sections) showing c-Kit+ cells in the proximal (a and b), mid (c and d) and distal (e and f) colon from wild-type (a, c and e) and Ws/Ws (b, d and f) rats. In wild-type rats (a, c and e) a high density of c-Kit+ cells is observed at the level of the AP surrounding the ganglia, at the submucosal (SubM) border and within both circular (CM) and longitudinal muscle (LM) layers. Small arrows in figure a show ICC-AP connected with ICC-IM in the circular muscle layer and small arrows in (c) indicate the ICC-AP protruding into the myenteric ganglia. Mutant rats only showed a few c-Kit+ cells at the AP region. Scale bar is for (a)–(f).

Mentions: In order to assess correlations between loss of electrical pacemaker activity [12] and ICC, c-Kit+ ICC were examined. In proximal, mid and distal colons of wild-type rats, c-Kit immunohistochemical staining on frozen sections showed c-Kit+ cells at the level of Auerbach’s plexus (ICC-AP), the submuscular plexus (ICC-SMP) and within the musculature (ICC-IM). ICC-APs were abundant and connected to each other to form a dense network at the level of Auerbach’s plexus (Fig. 1a, c and e). They usually surrounded the myenteric ganglia (Fig. 1a and c) and occasionally c-Kit+ cells were observed protruding into the ganglia (Fig. 1c). c-Kit+ ICC were also seen to extend into the circular and longitudinal muscle layers to connect with ICC-IM close to Auerbach’s plexus (Fig. 1a). c-Kit+ ICC-IM usually ran parallel to adjacent smooth muscle cells. c-Kit+ cells were also concentrated at the level of the SMP at the border of the submucosa (Fig. 1a, c and e) and formed a local network (not shown, see [12]). In the proximal and mid colons of Ws/Ws rats (Fig. 1b and d), relatively few c-Kit+ ICC-AP had developed, whereas hardly any ICC at the level of the SMP and within the muscle layers were encountered. There was hardly any c-Kit+ reaction at any level in the distal colon of Ws/Ws rats (Fig. 1f).


Igf1r+/CD34+ immature ICC are putative adult progenitor cells, identified ultrastructurally as fibroblast-like ICC in Ws/Ws rat colon.

Wang XY, Albertí E, White EJ, Mikkelsen HB, Larsen JO, Jiménez M, Huizinga JD - J. Cell. Mol. Med. (2009)

Immunohistochemistry (frozen sections) showing c-Kit+ cells in the proximal (a and b), mid (c and d) and distal (e and f) colon from wild-type (a, c and e) and Ws/Ws (b, d and f) rats. In wild-type rats (a, c and e) a high density of c-Kit+ cells is observed at the level of the AP surrounding the ganglia, at the submucosal (SubM) border and within both circular (CM) and longitudinal muscle (LM) layers. Small arrows in figure a show ICC-AP connected with ICC-IM in the circular muscle layer and small arrows in (c) indicate the ICC-AP protruding into the myenteric ganglia. Mutant rats only showed a few c-Kit+ cells at the AP region. Scale bar is for (a)–(f).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4516506&req=5

fig01: Immunohistochemistry (frozen sections) showing c-Kit+ cells in the proximal (a and b), mid (c and d) and distal (e and f) colon from wild-type (a, c and e) and Ws/Ws (b, d and f) rats. In wild-type rats (a, c and e) a high density of c-Kit+ cells is observed at the level of the AP surrounding the ganglia, at the submucosal (SubM) border and within both circular (CM) and longitudinal muscle (LM) layers. Small arrows in figure a show ICC-AP connected with ICC-IM in the circular muscle layer and small arrows in (c) indicate the ICC-AP protruding into the myenteric ganglia. Mutant rats only showed a few c-Kit+ cells at the AP region. Scale bar is for (a)–(f).
Mentions: In order to assess correlations between loss of electrical pacemaker activity [12] and ICC, c-Kit+ ICC were examined. In proximal, mid and distal colons of wild-type rats, c-Kit immunohistochemical staining on frozen sections showed c-Kit+ cells at the level of Auerbach’s plexus (ICC-AP), the submuscular plexus (ICC-SMP) and within the musculature (ICC-IM). ICC-APs were abundant and connected to each other to form a dense network at the level of Auerbach’s plexus (Fig. 1a, c and e). They usually surrounded the myenteric ganglia (Fig. 1a and c) and occasionally c-Kit+ cells were observed protruding into the ganglia (Fig. 1c). c-Kit+ ICC were also seen to extend into the circular and longitudinal muscle layers to connect with ICC-IM close to Auerbach’s plexus (Fig. 1a). c-Kit+ ICC-IM usually ran parallel to adjacent smooth muscle cells. c-Kit+ cells were also concentrated at the level of the SMP at the border of the submucosa (Fig. 1a, c and e) and formed a local network (not shown, see [12]). In the proximal and mid colons of Ws/Ws rats (Fig. 1b and d), relatively few c-Kit+ ICC-AP had developed, whereas hardly any ICC at the level of the SMP and within the muscle layers were encountered. There was hardly any c-Kit+ reaction at any level in the distal colon of Ws/Ws rats (Fig. 1f).

Bottom Line: A significantly higher number of Igf1r(+)/CD34(+) cells were found in Ws/Ws compared to wild-type rat colons.Immunohistochemistry revealed a reduction of neurons positive for neuronal nitric oxide synthase.The reduction in nitrergic innervation associated with the Ws mutation may be the result of a reduction in nitrergic neurons.

View Article: PubMed Central - PubMed

Affiliation: Department of Medicine, Farncombe Family Digestive Health Research Institute, McMaster University, Hamilton, Ontario, Canada.

ABSTRACT
The colon of Ws/Ws mutant rats shows impairment of pacemaker activity and altered inhibitory neurotransmission. The present study set out to find structural correlates to these findings to resolve mechanisms. In the colon of Ws/Ws rats, interstitial cells of Cajal associated with Auerbach's plexus (ICC-AP) were significantly decreased and ICC located at the submuscular plexus and intramuscular ICC were rarely observed based on immunohistochemistry and electron microscopy. Ultrastructural investigations revealed that there was no overall loss of all types of interstitial cells combined. Where loss of ICC was observed, a marked increase in fibroblast-like ICC (FL-ICC) was found at the level of AP. Immunoelectron microscopy proved FL-ICC to be c-Kit(-) but gap junction coupled to each other and to c-Kit(+) ICC; they were associated with enteric nerves and occupied space normally occupied by ICC in the wild-type rat colon, suggesting them to be immature ICC. In addition, a marked increase in immunoreactivity for insulin-like growth factor 1 receptor (Igf1r) occurred, co-localized with CD34 but not with c-Kit. A significantly higher number of Igf1r(+)/CD34(+) cells were found in Ws/Ws compared to wild-type rat colons. These CD34(+)/Igf1r(+) cells in the Ws/Ws colon occupied the same space as FL-ICC. Hence we propose that a subset of immature ICC (FL-ICC) consists of adult progenitor cells. Immunohistochemistry revealed a reduction of neurons positive for neuronal nitric oxide synthase. The functional capabilities of the immature ICC and the regenerative capabilities of the adult progenitor cells need further study. The morphological features described here show that the loss of pacemaker activity is not associated with failure to develop a network of interstitial cells around AP but a failure to develop this network into fully functional pacemaker cells. The reduction in nitrergic innervation associated with the Ws mutation may be the result of a reduction in nitrergic neurons.

Show MeSH
Related in: MedlinePlus