Nitric oxide donors for the treatment of osteoporosis.

The number of osteoporotic fractures is increasing worldwide as populations age. An inexpensive and widely available treatment is necessary to alleviate this increase in fractures. Current treatments decrease fractures at trabecular bone sites (spine) but have limited effects at cortical sites (hip, legs, forearm, and upper arm)-the most common sites of osteoporotic fracture. Treatments are also limited by costs, side effects, and lack of availability. Nitric oxide is a novel agent that has the potential to influence cortical bone, is inexpensive, is widely available, and has limited side effects. In this review we evaluate the in vitro and in vivo data which support the concept that nitric oxide is important in bone cell function, review the observational and case-control studies reporting on subjects taking organic nitrates that act as nitric oxide donors, and review the effects of nitrates on bone mineral density measurements and fracture risk.