Plant Polyphenol Intake Alters Gene Expression in Canine Leukocytes

Background/Aims: Polyphenol compounds may explain most of the health-related beneficial effects of plants and vegetables, mainly through their antioxidant properties. The aim of the study was to assess the main changes on leukocyte gene expression of dogs caused by intake of three natural polyphenol-rich extracts and to compare them with caloric restriction. Methods: 20 female dogs were divided into 5 groups: control fed ad libitum (C), caloric-restricted to 30% less than control (CR), and 3 groups fed ad libitum supplemented with citrus extract (CE), green tea extract (GTE) or grape seed extract (GSE). Leukocytes gene expression was analyzed in a specially designed microarray. Results: CE treatment mainly downregulated genes related to inflammative (IL-8, VLA-4) and cytotoxic response (GRP 58) as well as proliferation of leukocytes. GTE induced gene expression related to leukocyte proliferation and signaling (GNAQ, PKC-B). GSE upregulated some of the genes increased by CE treatment. CR downregulated genes related with energy metabolism (ATP5A1, COX7C) and inflammatory markers (VLA-4). Conclusion: A chronic ingestion of citric, grape seed and green tea polyphenols is able to modulate canine leukocyte functions through changes in gene expression. CE ingestion reduces expression of some genes also diminished by a 30% caloric restriction. Copyright (C) 2009 S. Karger AG, Basel