Antiretroviral Therapy Containing HIV Protease Inhibitors Enhances Fracture Risk by Impairing Osteoblast Differentiation and Bone Quality.

Long-term antiretroviral therapy is associated with increased fracture risk, but the mechanism remains elusive. We measured serum undercarboxylated osteocalcin and pentosidine (markers of poor bone quality) in human immunodeficiency virus-infected patients treated with protease inhibitors (PIs) or an integrase strand transfer inhibitor-containing regimen. The results demonstrated significantly higher undercarboxylated osteocalcin and pentosidine in PI-treated patients. Switching to integrase strand transfer inhibitor significant decreased these markers. We also showed impaired bone mechanical properties with higher undercarboxylated osteocalcin level in PI-treated mice and inhibited osteoblast differentiation in PI-treated osteogenic cells. The results confirmed the adverse effects of PIs on bone quality and osteoblast differentiation.