Conjugated Linoleic Acid and Bone Biology

Abstract

Osteoporosis, osteoarthritis and inflammatory joint disease afflict millions of people worldwide. Inflammatory cytokines inhibit chondrocyte proliferation and induce cartilage degradation for which part of the response is mediated by PGE2. Excess production of PGE2 is linked to osteoporosis and arthritis and is associated with bone and proteoglycan loss. PGE2 also influences the IGF-I/IGFBP axis to facilitate bone and cartilage formation. Recent investigations with growing rats given butter fat and supplements of CLA demonstrated an increased rate of bone formation and reduced ex vivo bone PGE2 production, respectively. Furthermore, the supplements of CLA isomers resulted in their enrichment in lipids of various bone compartments of animals. The effects of CLA on bone biology in rats (IGF action and cytokines) appear to be dependent on the level of n-6 and n-3 fatty acids in the diet; however, these studies generally showed that CLA decreased ex vivo bone PGE2 production and in osteoblast-like cultures. Anti-inflammatory diets, including nutraceutical applications of CLA, may be beneficial in moderating cyclooygenase 2 (COX-2) activity or expression (influencing PGE2 biosynthesis) and might help to reduce rheumatoid arthritis (secondary osteoporosis). This review summarizes findings of CLA on bone modeling in rats and effects on cellular functions of osteoblasts and chondrocytes. These experiments indicate that CLA isomers possess anti-inflammatory activity in bone by moderating prostanoid formation.

Osteoprotective effect of soybean and sesame oils in ovariectomized rats via estrogen-like mechanism

“…Naturally, active osteoclasts reside on the mineralized surface of bone where they release free radicals and lysosomal enzymes for dissolving the minerals and degrading bone matrix (Watkins and Seifert 2000). In the present study, the increased levels of total leukocytes, TNF-a and CRP, along with the increased activity of the lysosomal enzyme, ACP in the bone tissue of OVX rats enhanced osteoclastic activity with consequent bone loss.…”

Long-chain polyunsaturated fatty acids: Selected mechanisms of action on bone

“…Once secreted and deposited in bone matrix, IGFs are released during osteoclastic bone resorptive activity, acting in an autocrine or paracrine fashion to stimulate new bone cell formation and matrix production [76]. IGF-I acts as a regulator of bone cell function as it stimulates the proliferation of pre-osteoblasts, thereby increasing the number of cells capable of producing bone matrix.…”

Fatty acid profile of <i>Longissimus dorsi</i> muscle of crossbred pigs fed with addition of conjugated linoleic acid or sunflower oil

“…Conjugated linoleic acid is anti-cancerogenic, prevents fat deposition and arteriosclerosis, stimulates the immune system and has anti-inflammatory properties (Basu et al 2000, MacDonald 2000, McCarty 2000, Kritchevsky 2000, Watkins & Seifert 2000, PanczenkoKresowska & Ziemlański 2001, Pfeuffer 2001, Whigham et al 2002, Bawa 2003, Ip et al 2003. Dietetic value of pork depends on carcass fat content and on fatty acid profile, especially on hypocholesterolemic acids.…”