Apoptosis in the intestinal mucosa of patients with inflammatory bowel disease: evidence of altered expression of FasL and perforin cytotoxic pathways.
OBJECTIVE
Abnormal apoptosis may result in the persistence of activated intestinal T-cells in inflammatory bowel disease (IBD). We investigated apoptosis in distinct mucosal compartments, and the expression of Fas/Fas ligand and perforin in the inflamed and non-inflamed intestinal mucosa of patients with IBD.


METHODS
Colon specimens from 15 patients with ulcerative colitis (UC) and inflamed and non-inflamed mucosa from 15 patients with Crohn's disease (CD) were analysed for densities and distribution of apoptotic cells determined by the terminal deoxynucleotidyltransferase-mediated dUDP-biotin nick-end labelling (TUNEL) method. Fas, FasL, and perforin-expressing cells were assessed by immunoperoxidase, and with anti-CD3, anti-CD20 and anti-CD68, by double immunofluorescence with confocal microscopy. Quantitative analysis was performed using a computer-assisted image analyser.


RESULTS
Colonic lamina propria (LP) and epithelium from patients with UC showed higher rates of apoptosis than controls, but no difference was shown regarding patients with CD. In LP, co-expression of Fas was reduced with T-cells in inflamed CD mucosa, and with macrophages in all patients with IBD. No difference was found in the expression of Fas on B-cells. Rates of FasL-expressing cells in LP were higher in IBD than in controls, with no correlation with the rates of apoptosis. Rates of perforin-expressing cells in LP were greater in UC than in controls, and correlated to the rates of apoptosis. No difference was shown regarding the inflamed and non-inflamed CD mucosa. Rates of FasL and perforin-expressing intra-epithelial lymphocytes showed no difference among groups.


CONCLUSIONS
Increased expression of FasL in IBD colonic LP not parallelled by Fas on T-cells and macrophages may indicate a reduced susceptibility to the Fas/FasL-mediated apoptosis of lymphoid cells. Expression of perforin is correlated to the tissue damage, and may represent the enhancement of a distinct cytotoxic pathway in UC.
Souza
Heitor S P
HS
Departamento de Clínica Médica, Laboratório Multidisciplinar de Pesquisa, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro 21941-590, Brazil. hsouza@hucff.ufrj.br
Tortori
Claudio J A
CJ
Castelo-Branco
Morgana T L
MT
Carvalho
Ana Teresa P
AT
Margallo
Victor S
VS
Delgado
Carlos F S
CF
Dines
Ilana
I
Elia
Celeste C S
CC
D000293:Adolescent; D000328:Adult; D000368:Aged; D000906:Antibodies / Q000276:immunology; D015703:Antigens, CD / Q000276:immunology; D018951:Antigens, CD20 / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000276:immunology; D017209:Apoptosis / Q000502:physiology*; D015415:Biomarkers / Q000378:metabolism; D002452:Cell Count; D003093:Colitis, Ulcerative / Q000378:metabolism / Q000473:pathology; D003106:Colon; D003424:Crohn Disease / Q000378:metabolism / Q000473:pathology; D053222:Fas Ligand Protein; D005260:Female; D005455:Fluorescent Antibody Technique; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D020287:In Situ Nick-End Labeling; D015212:Inflammatory Bowel Diseases / Q000378:metabolism / Q000473:pathology*; D007413:Intestinal Mucosa / Q000378:metabolism / Q000648:ultrastructure*; D008297:Male; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000276:immunology; D018613:Microscopy, Confocal; D008875:Middle Aged; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; D000097382:CD68 Molecule
D000906:Antibodies; D015703:Antigens, CD; D018951:Antigens, CD20; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D054353:Perforin; D052899:Pore Forming Cytotoxic Proteins; C067980:CD68 antigen, human; D000097382:CD68 Molecule; C505661:FASLG protein, human