Pathology

Fibrosis

Pathogenesis

Gastroenterology

Immunohistochemistry

Hepatic stellate cell

Collagenous colitis

Diarrhea

Medicine

The American Journal of Gastroenterology

Purpose: Collagenous colitis (CC) is an important cause of chronic diarrhea of unknown pathogenesis, and confusion exists as to which histologic or clinical features best define the illness. Stellate cells have been described as the primary effector cell for hepatic fibrosis, and more recently implicated in the pathogenesis of fibrosis in chronic pancreatitis. The primary objective of our study was to determine if a relationship exists between absolute numbers of colonic interstitial stellate cells and subepithelial collagen layer thickness. Methods: We randomly selected 32 cases from our pathology database, 20 whom had collagenous colitis determined by subepithelial collagen table of ≥10 microns, and 12 cases whose biopsies showed non-specific inflammation and collagen layer thickness <10 microns. All subjects had undergone lower endoscopy for evaluation of chronic diarrhea. The control group consisted of 4 cases with functional complaints, and non-specific findings on mucosal biopsies. Trichrome stain was performed to determine an average thickness of the subepithelial collagen table. Antibody to smooth muscle actin (SMA) was used to identify mucosal stellate cells via an automated immunohistochemical technique. The number of peri-cryptal and interstitial stellate cells was counted (10 hpf) independently by three pathologists. Results: There was a linear correlation between the number of interstitial stellate cells and collagen layer thickness (Fig 1). Mucosal biopsies from patients with CC had significantly more stellate cells compared to those with non-specific chronic inflammation (p= 0.06) or controls (p <0.0001). There were no significant differences in the number of peri-cryptal stellate cells for the three groups.Figure 1Conclusions: Our study suggests that stellate cells may be the effector cell responsible for synthesis and deposition of the collagen layer in subjects with collagenous colitis. Further investigations of mucosal interstitial stellate cells, correlation with collagen thickness and clinical symptoms will be important in order to more accurately diagnose and treat collagenous colitis. [figure 1]

Correlation of Colonic Interstitial Stellate Cells with Subepithelial Collagen Layer Thickness