Serum beta-2 microglobulin is a marker of high bone remodelling in elderly women.
Beta-2 microglobulin (beta2m), the water soluble extrinsic light chain of class I MHC, has been recently isolated from the adult bone culture medium. Serum beta2m plays a role as a bone-derived growth factor regulating both osteoblast and osteoclast cell activity. Serum beta2m has been proposed as a bone remodeling biological marker in high bone turnover conditions. The purpose of our study was to determine the relationship between beta2m and vitamin D status in post-menopausal women. We have studied 44 healthy women from 20 to 80 years with normal hepatic and renal function, without diabetes mellitus and/or inflammatory, tumoral or infectious diseases. We measured the serum levels of calcium, phosphorus, parathyroid hormone (PTH), vitamin D binding protein (DBP), 25-OHD3 (calcidiol), 1,25(OH)2D3 (calcitriol) and beta2m. Serum beta2m levels increased with age (r = 0.54, P < 0.001). Post-menopausal women had higher serum levels than pre-menopausal women of beta2m (1.76 +/- 0.22 mg/l vs. 1.35 +/- 0.2 mg/l, P < 0.01); PTH (61.5 +/- 7.5 ng/ml vs. 39 +/- 6 ng/ml, P < 0.001) and lower serum levels of 25-OHD3 (7.5 +/- 2.3 ng/ml vs. 18.2 +/- 2.5 ng/ml, P < 0.001). Moreover, serum levels of beta2m were negatively correlated with 25-OHD3 (r = -0.34, P < 0.05) and with ionized calcium (r = -0.45, P < 0.01) and positively with PTH (r = 0.48, P < 0.01). These results support the role of beta2m as a regulator of bone metabolism and its potential use as a marker of high bone turnover in post-menopausal women, specially in elderly women with vitamin D deficiency and secondary hyperparathyroidism.
Unidad de Metabolismo Mineral, Hospital Universitario Reina Sofia, Facultad de Medicina y Departamento de Biología Celular, Universidad de Córdoba, Spain.
J M
JM
Quesada
J
J
Alonso
J
J
Gonzalez
R
R
Muñoz
I
I
Jans
A
A
Martiu
R
R
Bouillon
D000328:Adult; D000368:Aged; D000375:Aging / Q000097:blood / Q000502:physiology*; D015415:Biomarkers; D016723:Bone Remodeling / Q000502:physiology*; D005260:Female; D006801:Humans; D008875:Middle Aged; D001613:beta 2-Microglobulin / Q000378:metabolism*
D015415:Biomarkers; D001613:beta 2-Microglobulin