The effect of tenofovir on bone remodeling.

Abstract

With the introduction of Highly Active Anti-Retroviral Therapy (HAART), HIVinfected patients have had long-term survival rates increase dramatically. A significant sequela from HIV-infection and side effect from some HAART medications is the loss of bone mineral density. The purpose of this study was to investigate the effects of a common HAART medication, tenofovir, on bone cells. It was hypothesized that tenofovir alters the gene expression of osteoblasts and osteoclasts, which creates an imbalance in the bone remodeling system and skeletal change. To test this, mice were treated with tenofovir, then serum was obtained to determine changes in osteocalcin, osteopontin, and carboxyl telopeptides of type I collagen activity. Furthermore, changes in osteoclast numbers were obtained by tartrate resistant acid phosphatase staining of mouse femurs. While other studies have shown that gene expression is altered in tenofovir treated cells, the present study did not find a significant difference in osteocalcin, osteopontin or carboxyl telopeptide of type I collagen activity for tenofovir mice. However, tenofovir decreased the number of osteoclasts in tartrate resistant acid phosphatase stained sections in mice. Given that HIV patients taking tenofovir medication have an increase in osteoporosis and the results of this study indicate tenofovir alone creates osteopetrotic effect, further studies are needed to determine the relationship between HIV infection and tenofovir.