ACP5 and osteoporosis: In accordance, Liu and colleagues have observed in a mouse model of dexamethasone-induced secondary osteoporosis that celastrol not only improves lipid metabolism and reduces hypercalciuria, but also mitigates articular cartilage lesions, decreases NF-kB, MMP-1, and MMP-9 expression, and reduces serum PTH, tartrate-resistant acid phosphatase (TRACP)5b, CTX-I, as well as deoxypyridinoline (DPD), suggesting that it ameliorates abnormal bone metabolism (50).