Age-related changes in lamin A/C expression in the osteoarticular system: Laminopathies as a potential new aging mechanism

Background: Mutations in lamin A/C have been described as associated to severe changes in bone and joints. In this study we hypothesize that the expression of lamin A/C may play a role in the pathogenesis of age-related diseases in the osteoarticular system. Methodology: C57BL/6 young and old mice (4 months; n = 10 and 24 months; n = 10) were sacrificed. Limbs were isolated for histopathological and Western blot analysis. The proportion of cells (osteoblasts and chondrocytes) positive for lamin A/C was quantified by immunohistochemistry. Lamin B I was used as control. Finally, lamin A/C expression in bone marrow cells was quantified by Western blot. Results: A significant reduction in lamin A/C was found in osteoblasts of old as compared to young mice (42% versus 76%, p < 0.001). Interestingly, lamin A/C but not lamin B I expression was found in bone matrix with higher levels in young bone. Additionally, a significant reduction in the number of lamin A/C expressing chondrocytes was seen in old mice as compared to young mice (32% versus 84%, p < 0.001). Finally, a reduction in lamin A/C expression was found in bone marrow cells obtained from old mice as compared to young mice. Conclusion: This is the first assessment of the age-related changes in lamin A/C expression in the osteoarticular system. We conclude that with aging there is a reduction in lamin A/C expression which could have a significance on osteoarticular cells function and viability. (c) 2005 Elsevier Ireland Ltd. All rights reserved.