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Effects of Dietary Resistant Starch on the Wnt Signaling Pathway and Preneoplastic Cells in the Colons of
Nicole Cray1,2, Yinsheng Zhao2,3, Yinan Fang4
1a Department of Veterinary Pathology , Iowa State University , Ames , Iowa , USA.
Abstract:
Dietary resistant starch (RS) has been suggested to reduce colonic neoplasia. To determine the effects of digestion-resistant cornstarch on colonic carcinogenesis and Wnt signaling in azoxymethane (AOM)-treated F344 rats, diets containing naturally occurring RS from corn lines derived partially from Guat209 (GUAT), AR16035 (AR), or a hybrid (ARxGUAT), containing 34.5 ± 2.0, 0.2 ± 0.1, and 1.9 ± 0.1% RS, respectively, were fed at 55% of the diet. GUAT-fed rats had increased cecal content and tissue weight and decreased cecal pH compared with AR- or ARxGUAT-fed rats. Numbers of aberrant crypt foci (ACF) were not different among diet groups. Increased numbers of crypts/focus were observed in AOM-injected rats fed GUAT compared with rats fed other diets. β-catenin mRNA expression of the crypts was significantly increased in GUAT-fed rats injected with AOM relative to those injected with saline. These findings suggest that selected dietary RSs may at some level further enhance colonocyte proliferation and differentiation in an AOM-treated colon.
Insights
Dietary resistant starch (RS) from specific corn lines may influence colon cancer development. High-RS diets increased colonocyte proliferation in rats, suggesting complex effects on colonic neoplasia.
Area of Science:
- Gastroenterology
- Oncology
- Nutritional Science
Background:
- Dietary resistant starch (RS) is proposed to inhibit colonic neoplasia.
- Understanding the impact of specific RS types on colon carcinogenesis is crucial.
Purpose of the Study:
- To investigate the effects of digestion-resistant cornstarch on colonic carcinogenesis.
- To examine the influence on Wnt signaling in azoxymethane (AOM)-treated rats.
Main Methods:
- Rats were fed diets with varying levels of RS from different corn lines (GUAT, AR, ARxGUAT).
- Colonic carcinogenesis was induced using azoxymethane (AOM).
- Cecal parameters, aberrant crypt foci (ACF), and beta-catenin mRNA expression were analyzed.
Main Results:
- High-RS (GUAT) diets increased cecal content and decreased pH.
- No significant differences in the number of aberrant crypt foci (ACF) were observed among diet groups.
- AOM-treated rats fed the GUAT diet showed increased crypts per focus and elevated beta-catenin mRNA expression.
Conclusions:
- Selected dietary resistant starches may enhance colonocyte proliferation and differentiation.
- The findings suggest a complex role for RS in AOM-induced colon cancer, potentially promoting proliferation at certain levels.