Bone marrow cells in murine colitis: multi-signal analysis confirms pericryptal myofibroblast engraftment without epithelial involvement.
BACKGROUND
The contribution of bone marrow-derived cells to epithelial tissues in the inflamed gut remains controversial. Recent reports have suggested that cell fusion between bone marrow-derived cells and the intestinal epithelium takes place in inflammatory conditions.


METHODS
In attempts to confirm this, we have undertaken gender mis-matched bone marrow (BM) transplants from male Swiss Webster (SWR) mice to B and T cell-deficient female Rag2 KO mice which, 4 weeks later, were given 5% dextran sodium sulphate in drinking water to induce acute colitis. A further BM-treated group of animals with a graft versus host-like condition was also studied. We developed a new method to combine up to three brightfield or fluorescent lectin- or immuno-histochemical signals with fluorescent in situ hybridisation for the Y and X chromosomes to enable us unequivocally to identify BM-derived male cells which presented as different cell types in the gastrointestinal tract.


RESULTS
In rolled preparations of whole intestines we scanned around 1.5 million crypts at many tissue levels. In no instance did we see a Y chromosome-positive cell in the epithelial compartment, which was not also CD45-positive. We saw no evidence of cell fusion, based on combined X and Y chromosome analysis. Levels of CD45-positive stromal and lymphoid cells and pericryptal myfibroblasts (positive for α-smooth muscle actin) increased with time up to a plateau, which resembled the level seen in untreated control grafted animals. We saw very few Y chromosome-positive endothelial cells in intestinal stromal vessels.


CONCLUSIONS
We conclude that whole BM transplantation does not result in intestinal epithelial engraftment in this model. Our new methods can usefully assist in multi-signal analyses of cell phenotypes following BM transplant and in models of chimaerism and regenerative medicine.
Histopathology Laboratory, Cancer Research UK, London Research Institute, London, United Kingdom.
Chung-Yin
CY
Lee
Rosemary
R
Jeffery
Gillian
G
Hutchinson
Malcolm R
MR
Alison
Richard
R
Poulsom
Nicholas A
NA
Wright
William R
WR
Otto
D000818:Animals; D001854:Bone Marrow Cells / Q000473:pathology*; D003092:Colitis / Q000473:pathology*; D016264:Dextran Sulfate; D005260:Female; D006086:Graft vs Host Disease / Q000276:immunology / Q000473:pathology; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D007413:Intestinal Mucosa / Q000473:pathology*; D017493:Leukocyte Common Antigens / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D058628:Myofibroblasts / Q000637:transplantation*; D037121:Plant Lectins / Q000378:metabolism; D014960:X Chromosome / Q000378:metabolism; D014998:Y Chromosome / Q000378:metabolism
D037121:Plant Lectins; C036554:dolichos biflorus agglutinin; D016264:Dextran Sulfate; D017493:Leukocyte Common Antigens