Age-related changes in the expression of cadherin-11, the mesenchyme specific calcium-dependent cell adhesion molecule

Cadherin-11 is a calcium-dependent cell adhesion molecule that is expressed in cells of the mesenchymal lineage during embryonic development. In this study we show, for the first time, that cadherin-11 gene is expressed in the bone marrow and bone cells obtained from rabbits of various age groups. Furthermore, a quantitative measurement of gene expression revealed that cadherin-11 was expressed in young rabbits (6 week-old: open epiphysis) at a level of 6.7 x 10(5) +/- 0.7 x 10(5) molecules: in mature rabbits (8-10 month-old: closed epiphysis) at 11 x 10(5) +/- 0.9 x 10(5) molecules; and in aged rabbits (4-5 year-old) at a level of 1.2 x 10(5) +/- 0.2 x 10(5) molecules/mu g total RNA. The relative level of cadherin-11 gene expression in mature rabbit marrow was found to be approximately 50% greater than in young rabbits. However, aged animals showed a reduction in cadherin-11 specific gene expression of greater than 900% as compared with mature animals. Age-related changes in bone remodeling/turnover lead to reduced bone density and high fracture risk, and since cadherins play a crucial role in tissue morphogenesis, this marked decrease may represent an index of the aging process in bone.