Lipoic Acid Helps Prevent Bone Loss

Byron's Comments:

Lipoic Acid regulates the gene signal NF-kappaB and in so doing helps prevent excess osteoblast activity.

Study Title:

Lipoic Acid Inhibits Inflammatory Bone Resorption by Suppressing Prostaglandin E2 Synthesis.

Study Abstract:

-Lipoic acid (LA) has been intensely investigated as a therapeutic agent for several pathological conditions, including diabetic polyneuropathy. In the present study, we examined the effects of LA on osteoclastic bone loss associated with inflammation. LA significantly inhibited IL-1-induced osteoclast formation in cocultures of mouse osteoblasts and bone marrow cells, but LA had only a marginal effect on osteoclastogenesis from bone marrow macrophages induced by receptor activator of NF-B ligand (RANKL). LA inhibited both the sustained up-regulation of RANKL expression and the production of PGE2 induced by IL-1 in osteoblasts. In addition, treatment with either prostaglandin E2 (PGE2) or RANKL rescued IL-1-induced osteoclast formation inhibited by LA or NS398, a specific cyclooxygenase-2 (COX-2) inhibitor, in cocultures. LA blocked IL-1-induced PGE2 production even in the presence of arachidonic acid, without affecting the expression of COX-2 and membrane-bound PGE2 synthase. Dihydrolipoic acid (the reduced form of LA), but not LA, attenuated recombinant COX-2 activity in vitro. LA also inhibited osteoclast formation and bone loss induced by IL-1 and LPS in mice. Our results suggest that the reduced form of LA inhibits COX-2 activity, PGE2 production, and sustained RANKL expression, thereby inhibiting osteoclast formation and bone loss in inflammatory conditions.

Study Information:

Hyunil Ha, Jong-Ho Lee, Ha-Neui Kim, Hyun-Man Kim, Han Bok Kwak, Seungbok Lee, Hong-Hee Kim and Zang Hee Lee. Lipoic Acid Inhibits Inflammatory Bone Resorption by Suppressing Prostaglandin E2 Synthesis. The Journal of Immunology 2006 August , 176: 111-117,
Department of Cell and Developmental Biology, DRI, BK21 Program, Seoul National University College of Dentistry, Seoul, Korea.

Full Study:

http://www.jimmunol.org/cgi/content/full/176/1/111