Adverse effects of valproate on bone: Defining a model to investigate the pathophysiology

Susan M. Senn, Susan Kantor, Ingrid J. Poulton, Margaret J. Morris, Natalie A. Sims, Terence J. O'Brien, John D. Wark

Research output: Contribution to journalArticleResearchpeer-review

35 Citations (Scopus)

Abstract

Purpose: Bone disease and fractures are common with chronic antiepileptic drug (AED) therapy, but the underlying mechanisms are poorly understood. This study aimed to characterize adverse bone effects of valproate and to identify mouse strains either resistant or sensitive to these effects. Methods: Seven mouse strains (n = 40/strain; 10/diet) were screened for the effect of chronic (8 weeks) valproate treatment (0, 2, 4, and 6 g/kg food) on total bone mineral content (BMC, by dual energy x-ray absorptiometry). In a confirmatory study the effect of valproate (0 or 4 g/kg food) over 16 weeks was assessed in five of the mouse strains (n = 60/strain; 30/diet) identified in the screening phase as either sensitive or resistant. Ex vivo volumetric bone measures and structural changes were assessed using peripheral quantitative computed tomography (pQCT) and histomorphometry. Results: Chronic valproate treatment reproducibly affected bone in C3H/HeJ mice, with a 9.1% (p < 0.01) reduction in total BMC and a 10.7% (p < 0.01) reduction in trabecular volumetric density, indicating a sensitive strain to AED-induced bone loss. Histomorphometry was consistent, revealing reductions in trabecular volume (19.6%, p < 0.05) and number (14.3%, p < 0.04), and a 19.9% (p < 0.05) increase in trabecular separation. In contrast the A/J mice were reproducibly resistant to the bone effects. Conclusion: Mouse strains sensitive and resistant to the adverse bone effects of chronic valproate treatment were identified. The strain-specific effects suggest a role of genetic factors in the pathogenesis of AED-induced bone disease. This novel model provides a new, powerful tool to investigate the pathophysiology and therapy of AED-associated bone disease.

Original languageEnglish
Pages (from-to)984-993
Number of pages10
JournalEpilepsia
Volume51
Issue number6
DOIs
Publication statusPublished - 2010
Externally publishedYes

Keywords

  • Antiepileptic drugs
  • Bone
  • Dual energy x-ray absorptiometry
  • Mice
  • Valproate

Cite this