Increased presence of eosinophilic granulocytes expressing transforming growth factor-beta1 in collagenous colitis.
BACKGROUND
Collagenous colitis is a disease characterized by chronic watery diarrhea, and on microscopic examination of colonic tissue, a typical thickening of the subepithelial collagen layer is seen. The etiology and pathophysiology behind this disease state are largely unknown.


METHODS
We have used in situ hybridization and immunohistochemistry to study the expression of transforming growth factor (TGF) -beta1, a growth factor with the capacity to cause accumulation of collagen in tissues, in collagenous colitis. Colonic pinch biopsy specimens from a total of 34 patients were investigated: 17 patients with collagenous colitis and 17 controls.


RESULTS
In patients with collagenous colitis there was increased expression of the TGF-beta1 gene compared with controls, as visualized by in situ hybridization. The vast majority of the TGF-beta1-expressing cells were eosinophils, both in collagenous colitis and controls, but there were also scattered fibroblastic and histiocytic stromal cells. Immunohistochemistry showed the presence of TGF-beta1, mainly in eosinophils, in the colonic mucosa. Morphometric quantification showed 603 +/- 192 eosinophils/mm2, (mean +/- standard error of the mean) in the colonic mucosa of patients with collagenous colitis compared with 30 +/- 7 eosinophils/mm2 in the controls.


CONCLUSIONS
The present results suggest that eosinophils expressing TGF-beta1 may be of pathophysiologic importance in the connective tissue remodeling seen in collagenous colitis.
Ståhle-Bäckdahl
M
M
Dept. of Dermatology, Karolinska Hospital, Stockholm, Sweden.
Maim
J
J
Veress
B
B
Benoni
C
C
Bruce
K
K
Egesten
A
A
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003092:Colitis / Q000378:metabolism* / Q000473:pathology; D003094:Collagen / Q000378:metabolism; D003106:Colon / Q000473:pathology; D004804:Eosinophils / Q000378:metabolism* / Q000473:pathology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007413:Intestinal Mucosa / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016212:Transforming Growth Factor beta / Q000096:biosynthesis*; D053773:Transforming Growth Factor beta1
C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D003094:Collagen