1a.Objectives (from AD-416):
Determine the effects of feeding pigs both A-type and B-type proanthocyanidins
on pig intestinal epithelium cell line (IPEC-1); on the bioavailability, changes in fecal microbiota, intestinal function, local gene expression, and metabolomic patterns in urine and feces; and on the ex-vivo inhibition of bacteria that cause urinary tract infections.
1b.Approach (from AD-416):
ARS will acquire the basic knowledge of the effects of consuming proanthocyanidins in a pig model on epithelial cell function, changes in intestinal microbiome and function, and inhibition of bacterial pathogens on epithelial cell surfaces. This information will be used by both ARS and the Cooperator to jointly develop novel molecular and metabolomic techniques related to the study of proanthocyanidins. The Cooperator will evaluate the results of the analysis of phenolic metabolites in urine and use pure phenolic acids available as commercial standards and/or their mixtures to confirm the results from the urine assays.
Proanthocyanidins are oligomers and polymers of flavan-3-ols, which are amongst the most abundant and bioactive polyphenols in the human diet. IPEC-1 cells are a non-transformed, non-tumorigenic cell line from pig’s small intestine (ileum), that serve as a useful model for human to simulate innate immune functions of the intestinal epithelium. In the present work, IPEC-1 cells were used to determine the effect of proanthocyanidins on the inflammatory response. Cells were pre-treated with high-purified proanthocyandin extracts from cranberry and grape seed under non-stimulated and LPS-stimulated conditions during a 48 h total incubation period. No significant changes in cell viability or apoptosis were found during the different incubation experiments, indicating that IPEC-1 is valid model to test the effects of proanthocyanidins on the immune response. Cell adhesion markers (ICAM-1) and chemokine (CCL20, and IL8) messenger RNA expression significantly increased as a result of incubation with the proanthocyanidins extracts. Protein levels of IL-8 were also in good agreement with gene expression. These results suggested that proanthocyanidins stimulate the inflammatory response of IPEC-1 cells, an effect that might be beneficial for certain immune-related diseases. Moreover, additional experiments on IPEC-1 carried out with purified proanthocyanidin compounds (procyanidins A2 and B2) also confirmed the stimulation of the inflammatory response previously observed with the extracts.