Serum beta(2)-microglobulin reflects increased bone resorption in immobilized stroke patients

Objective: The so-called bone-derived growth factor, beta (2)-microglobulin , has a regulatory function in bone metabolism by stimulating osteoclast ac tivity. We undertook this study because osteoclast activity is known to be enhanced in patients with immobilized stroke, suggesting that their beta (2 )-microglobulin concentrations may be increased. Design: We studied 79 patients with acute stroke hemiplegia, including 36 m en and 43 postmenopausal women ranging in age between 51 and 70 yr. Results: The mean Barthel Index was 43 and 42 for men and women, respective ly. The serum beta (2)-microglobulin concentration was increased in male an d female patients, compared with the findings of 44 age-matched control sub jects, and the serum concentration of pyridinoline cross-linked carboxyterm inal telopeptide of type 1 collagen was also increased in male and female p atients, compared with the findings of the control subjects. Serum concentr ations of pyridinoline cross-linked carboxyterminal telopeptide of type 1 c ollagen correlated negatively with Barthel Index scores in both genders, in dicating increased bone resorption caused by immobilization in these patien ts. Linear regression analysis revealed a positive correlation between beta (2)-microglobulin and pyridinoline crosslinked carboxyterminal telopeptide of type 1 collagen in both genders. Conclusions: These findings suggest that beta (2)-microglobulin reflects os teoclastic activity in response to stroke-induced immobilization in both ge nders. beta (2)-microglobulin is a useful indicator of bone resorption in p atients with immobilized stroke.