Vaccine Halts Bone Loss in Mouse Studies

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Monday October 15 5:24 PM ET

Vaccine Halts Bone Loss in Mouse Studies

NEW YORK (Reuters Health) - An experimental vaccine has

been shown to help halt bone loss in mouse models of

osteoporosis and rheumatoid arthritis.

The vaccine seeks to block the action of a molecule known

as receptor activator of NF-kappaB ligand, or RANKL.

This molecule is known to play a role in the development

of bone cells. Evidence is mounting that it also may be

responsible for the destruction of bone that occurs in the

bone-thinning disease osteoporosis and in rheumatoid arthritis,

Dr. Mark Hertz of vaccine maker Pharmexa A/S in Horsholm,

Denmark, told Reuters Health in an interview.

Hertz reported on studies of the vaccine in mice Friday in

Phoenix, Arizona, during the 23rd Annual Meeting of The

American Society for Bone and Mineral Research.

Normally, removing the ovaries of mice causes them to lose

bone. But mice given the RANKL AutoVac vaccine before having

their ovaries removed did not lose bone mass.

And in mice genetically engineered to develop an

inflammatory joint disease similar to rheumatoid arthritis, the

vaccine ``almost completely prevented bone destruction,'' Hertz

and colleagues from The University of Tokyo and Tokyo Medical

and Dental University note.

Mice given the vaccine also had fewer osteoclasts, which

are cells that break down old bone.

``We're now developing humanized versions of this vaccine,''

Hertz told Reuters Health. ``They are going into preclinical

development and hope to enter phase I trials in 2003.''

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