Osteoporosis rodents

Studies have demonstrated that treatment with soy or phytoestrogen enriched diets is effective in conserving bone in rodent models of osteoporosis (Anderson and Gamer, 1998 Ishimi et al, 2000 Draper et al, 1997). The mechanism of action of phytoestrogens on bone health is unclear but several mechanisms including inhibition of bone resorption and stimulation of bone formation maybe involved (Fanti etal, 1998 Ishimi e/a/., 1999 Picherit eta/., 2000). Limited data from studies in postmenopausal women have indicated that phytoestrogen supplements have a small, beneficial effect on bone loss in the lumbar spine (Alekel et al, 2000 Potter et al, 1998 Somekawa et al, 2001). 

The standard model for the preclinical development of anti-osteoporosis therapies is the ovariectomized (OVX) rat. However, Cat K inhibitors developed specifically against the human enzyme are generally significantly less potent ( 2-orders of magnitude) against the rat and mouse enzymes than against human Cat K [9]. This loss of potency towards the rodent enzymes, which is consistent with their low sequence homology, therefore restricts the use of... 

There is no information on in utero developmental effects in humans exposed to HCB, but oral exposure of young children has caused small or atrophied hands, short stature, pinched facies, osteoporosis of the carpal, metacarpal, and phalangeal bones, and painless arthritic changes. HCB has been demonstrated to cross the placenta in humans and in rodents. HCB residues have been detected in human milk and adipose tissue and in the blood of the umbilical cord of newborn infants and their mothers. Teratogenic effects were not... 

In an effort to improve the benefit-to-risk ratio of PTH in the context of the uncertain relevance of the findings in rodents, it was strongly recommended that participation in clinical studies be limited to adults with severe osteoporosis who have completed bone maturation. It was further advised that any case of osteosarcoma (or other bone tumor) be immediately reported and long-term follow-up be conducted for patients treated with PTH. Importantly, subjects in clinical trials of PTH and PTH analogues should be informed about the occurrence of osteosarcomas in rodents. 

Extensive experiments have been carried out on aging rodents to determine the effect on bone loss of those dietary factors of possible importance in the etiology of human osteoporosis calcium, phosphorus, protein, fluoride. The results of these studies have been reviewed elsewhere (Draper, 1985 Yuen et al, 1984) and will be only briefly summarized here. Investigation of the possible role of vitamin D in bone loss in rodents is precluded by their low requirement for this vitamin. 

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