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Title: 10TRANS, 12CIS-LINOLEIC ACID REDUCES APOLIPOPROTEIN B SECRETION IN HEPG2 CELLS

Author
item YOTSUMOTO, H - SAGA UNIVERSITY, JAPAN
item HARA, E - SAGA UNIVERSITY, JAPAN
item NAKA, S - SAGA UNIVERSITY, JAPAN
item Adlof, Richard
item EMKEN, EDWARD - MIDWEST CONSULTANTS
item YANAGITA, T - SAGA UNIVERSITY, JAPAN

Submitted to: Food Science and Technology International
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/1/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Conjugated linoleic acid (CLA) is found in dairy products and processed meat and in human fluids and tissues. CLA and related fat structures have been promoted as reducing chemically induced cancers, suppressing atherosclerosis, as antidiabetics, and as weight loss agents. These fats have also been shown to influence the rate of fat digestion, but no research has yet determined the effects of specific CLA structures. Earlier studies used a mixture of fats, so it was not possible to link a specific effect to a specific fat. In the present study, we evaluated the effects of two representative CLAs (cis-9,cis-11-CLA and trans-10,cis-12- CL) on the rate of fat and cholesterol formation in cells. We found the 10,12-CLA to reduce fat and cholesterol formation by 30% when compared with the 9,11-CLA and with other, normal fats and that both CLAs reduced the formation of cholesterol. These results will help us to better understand how CLA works to lower fat and cholesterol levels in living systems.

Technical Abstract: Conjugated linoleic acids (CLAs) are a general term for positional/geometrical isomers of 9cis, 12cis-linoleic acid with cis- or trans-conjugated dienes. Conjugated linoleic acids are found in heat treated dairy products and processed meat. They are also formed through the bioconversion of linoleic acid by microorganisms present in the ruminant gastrointestinal tract. A small amount of conjugated linoleic acid has been reported to be present in human fluids and tissues. Conjugated linoleic acids have been suggested to have favorable physiological effects, including antitumor and antidiabetic activities. These molecules have also been shown to influence lipid metabolism in laboratory animals. In the present study, we evaluated the effects of two representative conjugated linoleic acids, 9cis, 11cis-linoleic acid and 10trans, 12cis-linoleic acid, on apoB secretion and the synthesis of triglyceride and cholesteryl ester by HepG2 cells, and made a comparison with the effect of 9cis, 12cis-linoleic acid. We used a low conjugated linoleic acid concentration, since high concentrations have been reported to be cytotoxic. HepG2 cells originated from a human liver and are known to retain the ability to regulate the synthesis and secretion of apoproteins and lipoproteins, as occurs with normal human hepatocytes.