Current status of drug therapies for osteoporosis and the search for stem cells adapted for bone regenerative medicine
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A number of factors can lead to bone disorders such as osteoporosis, in which the balance of bone resorption vs. bone formation is upset (i.e., more bone is resorbed than is formed). The result is a loss of bone mass, with a concomitant decrease in bone density. Drugs for osteoporosis can be broadly classified as “bone resorption inhibitors”, which impede bone resorption by osteoclasts, and “bone formation accelerators”, which augment bone formation by osteoblasts. Here, we describe representative drugs in each class, i.e., the bisphosphonates and the parathyroid hormone. In addition, we introduce two novel bone formation accelerators, SST-VEDI and SSH-BMI, which are currently under investigation by our research group. On the other hand, regenerative therapy, characterized by (ideally) the use of a patient’s own cells to regenerate lost tissue, is now a matter of global interest. At present, candidate cell sources for regenerative therapy include embryonic stem cells (created from embryos based on the fertilization of oocytes), induced pluripotent stem cells (created artificially by using somatic cells as the starting material), and somatic stem cells (found in the tissues of the adult body). This review summarizes the identifying features and the therapeutic potential of each of these stem cell types for bone regenerative medicine. Although a number of different kinds of somatic stem cells have been reported, we turn our attention toward two that are of particular interest for prospective applications in bone repair: the dedifferentiated fat cell, and the deciduous dental pulp-derived stem cell.
KeywordsOsteoporosis SST-VEDI SSH-BMI DFAT cell DDPSC
This work was supported in part by grants from A-STEP; Adaptable and Seamless Technology Transfer Program through target-driven R&D (Exploratory Research).
Conflict of interest
- Komrakova M, Stuermer EK, Werner C, Wicke M, Kolios L, Sehmisch S, Tezval M, Daub F, Martens T, Witzenhausen P, Dullin C, Stuermer KM (2010) Effect of human parathyroid hormone hPTH (1–34) applied at different regimes on fracture healing and muscle in ovariectomized and healthy rats. Bone 47:480–492PubMedCrossRefGoogle Scholar
- Ohta Y, Takenaga M, Tokura Y, Hamaguchi A, Matsumoto T, Kano K, Mugishima H, Okano H, Igarashi R (2008) Mature adipocyte-derived cells, DFAT (de-differentiated fat cells) promoted functional recovery from spinal cord injury-induced motor dysfunction in rats. Cell Transpl 17:877–886CrossRefGoogle Scholar
- Sakuma T, Matsumoto T, Kano K, Fukuda N, Obinata D, Yamaguchi K, Yoshida T, Takahashi S, Mugishima H (2009) Mature adipocyte derived dedifferentiated fat cells can differentiate into smooth muscle-like cells and contribute to bladder tissue regeneration. J Urol 182:355–365PubMedCrossRefGoogle Scholar
- Takagi Y, Hirano T, Yamada J (1989) Scale regeneration of tilapia (Oreochromis miloticus) under various ambient and dietary calcium concentrations. Comp Biochem Physiol 92A:605–608Google Scholar