Serum beta2-microglobulin reflects increased bone resorption in immobilized stroke patients.

Abstract

The so-called bone-derived growth factor, beta2-microglobulin, has a regulatory function in bone metabolism by stimulating osteoclast activity. We undertook this study because osteoclast activity is known to be enhanced in patients with immobilized stroke, suggesting that their beta2-microglobulin concentrations may be increased. We studied 79 patients with acute stroke hemiplegia, including 36 men and 43 postmenopausal women ranging in age between 51 and 70 yr. The mean Barthel Index was 43 and 42 for men and women, respectively. The serum beta2-microglobulin concentration was increased in male and female patients, compared with the findings of 44 age-matched control subjects, and the serum concentration of pyridinoline cross-linked carboxyterminal telopeptide of type 1 collagen was also increased in male and female patients, compared with the findings of the control subjects. Serum concentrations of pyridinoline cross-linked carboxyterminal telopeptide of type 1 collagen correlated negatively with Barthel Index scores in both genders, indicating increased bone resorption caused by immobilization in these patients. Linear regression analysis revealed a positive correlation between beta2-microglobulin and pyridinoline cross-linked carboxyterminal telopeptide of type 1 collagen in both genders. These findings suggest that beta2-microglobulin reflects osteoclastic activity in response to stroke-induced immobilization in both genders. Beta2-microglobulin is a useful indicator of bone resorption in patients with immobilized stroke.