Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation
Chronic inflammatory bowel disease (IBD) appears to predispose to subsequent colon cancer. Factors that influence the degree of this risk require definition since the reported incidence of malignant change varies widely. Differing environmental factors such as diet may be critical, and several appro...
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| Format: | Article |
| Language: | English |
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Wiley
1990-01-01
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| Series: | Canadian Journal of Gastroenterology |
| Online Access: | http://dx.doi.org/10.1155/1990/490581 |
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| _version_ | 1850170738501222400 |
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| author | Hugh J Freeman |
| author_facet | Hugh J Freeman |
| author_sort | Hugh J Freeman |
| collection | DOAJ |
| description | Chronic inflammatory bowel disease (IBD) appears to predispose
to subsequent colon cancer. Factors that influence the degree of this risk require
definition since the reported incidence of malignant change varies widely.
Differing environmental factors such as diet may be critical, and several approaches
have been used to explore the role of specific variables in colon cancer
pathogenesis; one has employed the use of animal models. Naturally occurring
models of colon cancer exist including cotton-topped tamarins with colitis. Best
studied, however, are animal models of colon cancer induced with specific
chemical carcinogens. Cycasin and hydrazine derivatives, eg, 1,2-dimethylhydrazine,
are most widely used. After parenteral administration of an active
carcinogen, metabolic activation occurs, resulting in colonic adenocarcinomas.
Sessile and polypoid neoplasms may be induced, particularly in the distal colon,
similar to human colon cancer. Using this model, the effect of differing dietary
and therapeutic variables has been explored. Studies with purified single dietary
fibres, such as microcrystalline cellulose and hemicellulose, but not pectin, have
demonstrated reduced numbers of colonic tumours; these in vivo observations
correlate with in vitro effects of fibres on rat luminal and fecal mutagenic
activities. Specific therapies used in IBD have also been evaluated - metronidazole,
for example, a bacterial mutagen, enhances the development of chemically
induced rodent colon cancer. In addition, a significant increase in colonic
tumour development occurs after intestinal resection or bypass, two procedures
used in the surgical management of IBD. In this setting, surgical sutures, particularly
nonabsorbable materials including stainless steel, may play a critical
role. Although the extent and duration of disease in patients with chronic IBD
may be important in colon cancer pathogenesis, other variables, including diet
and treatment, may be critical modulating factors. |
| format | Article |
| id | doaj-art-9b019fb4c6ac4f9fa5fb9de3603f7159 |
| institution | OA Journals |
| issn | 0835-7900 |
| language | English |
| publishDate | 1990-01-01 |
| publisher | Wiley |
| record_format | Article |
| series | Canadian Journal of Gastroenterology |
| spelling | doaj-art-9b019fb4c6ac4f9fa5fb9de3603f71592025-08-20T02:20:25ZengWileyCanadian Journal of Gastroenterology0835-79001990-01-014737237710.1155/1990/490581Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell DifferentiationHugh J FreemanChronic inflammatory bowel disease (IBD) appears to predispose to subsequent colon cancer. Factors that influence the degree of this risk require definition since the reported incidence of malignant change varies widely. Differing environmental factors such as diet may be critical, and several approaches have been used to explore the role of specific variables in colon cancer pathogenesis; one has employed the use of animal models. Naturally occurring models of colon cancer exist including cotton-topped tamarins with colitis. Best studied, however, are animal models of colon cancer induced with specific chemical carcinogens. Cycasin and hydrazine derivatives, eg, 1,2-dimethylhydrazine, are most widely used. After parenteral administration of an active carcinogen, metabolic activation occurs, resulting in colonic adenocarcinomas. Sessile and polypoid neoplasms may be induced, particularly in the distal colon, similar to human colon cancer. Using this model, the effect of differing dietary and therapeutic variables has been explored. Studies with purified single dietary fibres, such as microcrystalline cellulose and hemicellulose, but not pectin, have demonstrated reduced numbers of colonic tumours; these in vivo observations correlate with in vitro effects of fibres on rat luminal and fecal mutagenic activities. Specific therapies used in IBD have also been evaluated - metronidazole, for example, a bacterial mutagen, enhances the development of chemically induced rodent colon cancer. In addition, a significant increase in colonic tumour development occurs after intestinal resection or bypass, two procedures used in the surgical management of IBD. In this setting, surgical sutures, particularly nonabsorbable materials including stainless steel, may play a critical role. Although the extent and duration of disease in patients with chronic IBD may be important in colon cancer pathogenesis, other variables, including diet and treatment, may be critical modulating factors.http://dx.doi.org/10.1155/1990/490581 |
| spellingShingle | Hugh J Freeman Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation Canadian Journal of Gastroenterology |
| title | Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation |
| title_full | Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation |
| title_fullStr | Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation |
| title_full_unstemmed | Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation |
| title_short | Animal Studies of Colon Carcinogenesis and Altered Epithelial Cell Differentiation |
| title_sort | animal studies of colon carcinogenesis and altered epithelial cell differentiation |
| url | http://dx.doi.org/10.1155/1990/490581 |
| work_keys_str_mv | AT hughjfreeman animalstudiesofcoloncarcinogenesisandalteredepithelialcelldifferentiation |