Roni F. Kunst, Audrie L. Langlais, Deborah Barlow, Karen L. Houseknecht, Katherine J. Motyl
Atypical antipsychotic (AA) drugs, such as risperidone, are associated with endocrine and metabolic side effects, including impaired BMD acquisition and increased fracture risk. We have previously shown that risperidone causes bone loss through the sympathetic nervous system, and that bone loss is associated with elevated markers of thermogenesis in brown and white adipose tissue. Because rodents are normally housed in sub-thermoneutral conditions, we wanted to test whether increasing housing temperature would protect against bone loss from risperidone. Four weeks of risperidone treatment in female C57BL/6J mice at thermoneutral (28°C) housing attenuated risperidone-induced trabecular bone loss and led to a low-turnover bone phenotype, with indices of both bone formation and resorption suppressed in mice with risperidone treatment at thermoneutrality, whereas indices of bone resorption were elevated by risperidone at room temperature. Protection against trabecular bone loss was not absolute, however, and additional evidence of cortical bone loss emerged in risperidone-treated mice at thermoneutrality. Taken together, these findings suggest thermal challenge may be in part responsible for bone loss with risperidone treatment, and that housing temperature should be considered when assessing bone outcomes of treatments that impact thermogenic pathways.