Vitamin A and inflammation as regulators of bone formation

Osteoporosis and associated fractures is a huge burden for patients, heath care organizations and society, which will increase with the increasing age of the population.

Increased amounts of vitamin A is a recognized risk factor for secondary osteoporosis, but there is uncertainty which levels of vitamin A that have no harmful effects.

In this four-year project, we will in human epidemiological studies investigate the effect by vitamin A and its interaction with vitamin D and with physical activity on bone mass, bone formation and fractures in elderly women and men, and on peak bone mass in young men. In mice, we will investigate effects of vitamin A and its interactions with vitamin D on bone mass and bone formation.

We will also study the effect by vitamin A on the efficacy of two drugs used to stimulate bone formation in osteoporotic patients, and on its effect on experimental fracture healing.There is a need for new osteo-anabolic drugs since the ones currently used in the clinic mainly decrease vertebral fractures with considerably less efficacy on non-vertebral fractures, including hip fractures.

We will screen for osteo-anabolic factors produced in experimentally induced inflammation in mice with excessive local new bone formation.With this project, we aim to get a better insight in which serum levels of vitamin A that are optimal for not causing harmful effects in the skeleton and to find new potential target for developing novel bone anabolic drugs.