ROLE OF SHORT-CHAIN FATTY-ACIDS IN THE HIND GUT

Short-chain fatty acids (SCFA) are produced by microbial fermentation in the hindgut in considerable amounts. Most of the anions in hindgut contents are SCFA, mainly acetate, propionate and butyrate. SCFA are r apidly absorbed. Mechanisms involved in the transepithelial transport are discussed. Besides the contribution to the overall energy metaboli sm of animals or men, SCFA have a number of further important effects on the colonic mucosa. Factors affecting the pH of compartments in the mucosa, cell swelling, stimulation of mucin release and of mucosal bl ood flow are mentioned. Controversial reports are known on the role of SCFA in the metabolism of colonocytes. In spite of the conflicting op inions on the interaction between SCFA metabolism and the development of colitis ulcerosa, diverticulosis and colorectal cancer seems to exi st. The obscure differences between the effects of SCFA on cell prolif eration, differentiation and apoptosis of colonocytes in vivo and in v itro indicate that besides direct effects of SCFA systemic effects suc h as neural and humoral factors are of crucial importance. The opposin g effects of SCFA on proliferation and apoptosis in normal colonocytes and in colonic cancer cells may open possibilities for prevention and /or therapy of patients with colonic diseases.