Distribution Of Telocytes Research Articles

A loss of telocytes accompanies fibrotic remodelling of the colonic wall in ulcerative colitis

Crohn’s disease (CD) and ulcerative colitis (UC) are complex diseases in which the interaction of genetic, environmental and microbial factors drives chronic relapsing and remitting intestinal inflammation that finally leads to extensive tissue fibrosis. In UC, this results in a stiff, fibrotic colon unable to carry out peristalsis or to resorb fluids. Colonic dysmotility is often observed in UC patients and has been linked to severe damages of the enteric neural structures and a reduced density of interstitial cells of Cajal (ICC). Telocytes (TC), a peculiar type of stromal cells, have been recently identified in a variety of human tissues and organs, including the gastrointestinal tract. Several roles have been proposed for TC, including mechanical support, spatial relationships with different cell types, intercellular signalling and modulation of intestinal motility by spreading the slow waves generated by the pacemaker ICC. We have recently demonstrated that a loss of TC accompanies the fibrotic remodelling of the intestinal wall in CD patients. The aim of the present work was to investigate the presence and distribution of TC in colonic specimens from UC patients compared with controls. Archival paraffin-embedded full-thickness samples of the left colon from UC patients who underwent elective bowel resection and controls were collected. Tissue sections were stained with Masson’s trichrome to detect fibrosis. TC were identified by CD34 immunohistochemistry. Double immunofluorescence for CD34 and CD31 (vascular endothelial cells), alpha-SMA (smooth muscle cells, myofibroblasts) and c-kit (ICC) was also performed. In early fibrotic UC cases, fibrosis affected the muscularis mucosae and submucosa, while the muscularis propria was spared. In advanced fibrotic UC cases, fibrosis extended to affect the muscle layers and the myenteric plexus. Few TC were found in the muscularis mucosae and submucosa of both early and advanced fibrotic UC colonic wall. Conversely, numerous myofibroblasts were observed in the submucosa of all UC cases. In the muscle layers and at the myenteric plexus of early fibrotic UC, TC were preserved in their distribution. In the muscularis propria of advanced fibrotic UC, the network of TC was reduced or even completely absent around smooth muscle cells and myenteric plexus ganglia, paralleling the loss of the ICC network. In UC, the loss of TC accompanies the fibrotic remodelling of the colonic wall and might contribute to colonic dysmotility.

Telocytes in liver: electron microscopic and immunofluorescent evidence

Hepatic interstitial cells play a vital role in regulating essential biological processes of the liver. Telocytes (TCs), a novel type of interstitial cells firstly identified by Popescu and his coworkers, have been reported in many tissues and organs, but not yet in liver (go to http://www.telocytes.com). We used transmission electron microscopy and immunofluorescence (double labelling for CD34 and c-kit/CD117, or vimentin, or PDGF Receptor-α, or β) to provide evidence for the existence of TCs in mice liver. The distribution of TCs in liver was found to be of similar density in the four hepatic lobes. In conclusion, here we show the presence of TCs in mice liver. It remains to be determined the possible roles of TCs in the control of liver homeostasis and regeneration, the more so as a close special relationship was found between TCs and hepatic putative stem (progenitor) cells.

Telocytes in Crohn's disease

Crohn’s disease (CD) is a relapsing chronic inflammatory disorder that may involve all the gastrointestinal tract with a prevalence of terminal ileum. Intestinal lesions have a characteristic discontinuous and segmental distribution and may affect all layers of the gut wall. Telocytes (TC), a peculiar type of stromal cells, have been recently identified in a variety of tissues and organs, including gastrointestinal tract of humans and mammals. Several roles have been proposed for TC, including mechanical support, spatial relationships with different cell types, intercellular signalling and modulation of intestinal motility. The aim of our study was to investigate the presence and distribution of TC in disease-affected and -unaffected ileal specimens from CD patients compared with controls. TC were identified by CD34/PDGFRα immunohistochemistry. In affected CD specimens TC disappeared, particularly where fibrosis and architectural derangement of the intestinal wall were observed. In the thickened muscularis mucosae and submucosa, few TC entrapped in the fibrotic extracellular matrix were found. A discontinuous network of TC was present around smooth muscle bundles, ganglia and enteric strands in the altered muscularis propria. At the myenteric plexus, the loss of TC network was paralleled by the loss of interstitial cells of Cajal network. In the unaffected CD specimens, TC were preserved in their distribution. Our results suggest that in CD the loss of TC might have important pathophysiological implications contributing to the architectural derangement of the intestinal wall and gut dysmotility. Further functional studies are necessary to better clarify the role of TC loss in CD pathophysiology.