Two lanthanum salts—lanthanum carbonate (LaCO3) and Lancer, a lanthanide citrate mixture—were tested for their effects on bone metabolism in a small animal model for post-menopausal osteoporosis. Forty female outbred Wistar Han rats, sham-operated (SHAM) or ovariectomized (OVX) at four months old, were allotted into groups: SHAM, OVX control (negative control), OVX + LaCO3 (1.74 g/kg feed) and OVX + Lancer (8 g/kg feed).

Effects on bone were investigated by bone markers—osteocalcin (Oc) in serum and excretion of pyridinoline (PYD) in urine—and physical parameters of bone structure and composition (bone mass, calcium, phosphorus and magnesium content in bone crude ash). The animal model could be validated by differences between OVX control and SHAM.

Body mass and feed intake were the same among the four groups. Oc was clearly increased in the two experimental groups vs. SHAM and OVX control. Bone mass and calcium content in bone ash were significantly higher than in OVX control. The calcium/phosporus ratio in bone ash of the two lanthanide groups did not differ from SHAM. Bone-protecting effects of lanthanides were clearly demonstrated by an increased trabecular density, the region of interest for osteoporotic bone loss.

Results demonstrate an improvement of bone formation and bone-protecting effects of lanthanides in the OVX rat. Thus, lanthanum salts suggest a prevention of post-menopausal bone loss and may be of benefit in experimental osteopenia following ovariectomy.

Source : S.J. von Rosenberg and U.A. Wehr, 2012. Lanthanum salts improve bone formation in a small animal model of post-menopausal osteoporosis. JAPAN online July 2012. doi: 10.1111/j.1439-0396.2012.01326.x