Plasma soluble receptor for advanced glycation end-products and risk of colorectal adenoma

Receptor for advanced glycation end products (RAGE) plays an important role in promoting chronic inflammation with activation of NF-kappa B. Soluble form of RAGE (sRAGE) represents a naturally occurring competitive inhibitor of RAGE-mediated events. In a colonoscopy-based case-control study, we examined the associations of plasma levels of sRAGE, sTNF-aRI, sTNF-aRII, sIL-6R, EGF, IFN alpha 2, G-CSF, MCP1, TNF beta, and VEGF with risk of colorectal adenoma. We prospectively identified 158 cases with colorectal adenoma and 203 polyp-free controls who were frequency-matched according to age, sex, race, and time of blood draw. Exposure information was collected using a questionnaire and fasting plasma samples were obtained before the colonoscopy. We used Luminex bead-based multiplex assays to determine level of biomarkers. Multivariate logistic regression model was used to estimate odds ratio (OR) and its 95% confidence interval (CI). Cases had insignificant lower levels of sRAGE, and higher levels of EGF and VEGF than controls. When the highest compared with the lowest category, the OR (95% CI) of colorectal adenoma was 0.55 (0.31-0.96) (P trend = 0.03) for sRAGE and 1.75 (1.05-2.93) (P trend = 0.04) for VEGF, adjusting for age, smoking status, hypertension and type 2 diabetes. The inverse association between sRAGE and colorectal adenoma was seen only among those without hypertension (P interaction = 0.02). An inverse association between sRAGE and colorectal adenoma was in line with an inverse association between sRAGE and colorectal cancer previously reported. This study supported the involvement of RAGE-NF-kB related inflammatory mechanism in the formation of colorectal adenoma.