Osteoporosis: Min YK

Chan SP, Chen JF, Chu LW, Van DP, Hosking D, Ip TP, Koh L, Kung A, Lai NS, Lau E, Lee JK, Leewattana R, Min YK, Nghia ND, Boonsong O, Park HM, Ringe J, Setyohadi B, Shin CS, Soontrapa S, Taechakraichana N, Tanjung F, Tobing D, Tsai KS, Woo J, Yang RS. · c/o Department of Medicine, University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong Special Administrative Region, People's Republic of China. · Public Health Nutr. · Pubmed #18647434 No free full text.

Abstract: BACKGROUND: Vitamin D is essential for Ca absorption, prevention of falls and fracture, and maintenance of muscle strength and balance. Lack of awareness of the importance of vitamin D in bone health is common in Asia. OBJECTIVE: To define key statements, objectives and actions for improving osteoporosis management and vitamin D inadequacy in Asia. RESULTS AND CONCLUSION: This declaration was jointly produced by specialists at the Asia Metaforum on the Role of Vitamin D and the Management of Osteoporosis, held in September 2006 in Hong Kong, to define actions to prevent vitamin D insufficiency in Asia. Although developed specifically for Asia, some or all of these statements may be applicable to other regions of the world.

Lee SU, Park SJ, Kwak HB, Oh J, Min YK, Kim SH. · Laboratory of Chemical Genomics, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong-gu, Daejeon 305-600, Republic of Korea. · Pharmacol Res. · Pubmed #18822379 No free full text.

Abstract: In the field of osteoporosis, there has been growing interest in anabolic agents that enhance bone mass and improve bone architecture. In this study, we demonstrated that the ubiquitous plant triterpenoid, ursolic acid, enhances differentiation and mineralization of osteoblasts in vitro. We found that ursolic acid induced the expression of osteoblast-specific genes with the activation of mitogen-activated protein kinases, nuclear factor-kappaB, and activator protein-1. Additionally, noggin, an antagonist of bone morphogenetic proteins (BMPs), inhibited ursolic acid-induced osteoblast differentiation. Noggin also inhibited the activation of Smad and the induction of BMP-2 mRNA expression by ursolic acid in the late stage of osteoblast differentiation. Importantly, ursolic acid was shown to have bone-forming activity in vivo in a mouse calvarial bone formation model. A high proportion of positive immunostaining of BMP-2 was found in the nuclear region of woven bone formed by ursolic acid. These results suggested that ursolic acid has the anabolic potential to stimulate osteoblast differentiation and enhance new bone formation.

Kim MH, Ryu SY, Bae MA, Choi JS, Min YK, Kim SH. · Laboratory of Chemical Genomics, Korea Research Institute of Chemical Technology, P.O. Box 107, Yuseong-gu, Daejeon 305-600, Republic of Korea. · Food Chem Toxicol. · Pubmed #18786594 No free full text.

Abstract: In bone remodeling, an imbalance caused by increased bone resorption over bone formation leads to adult skeletal diseases such as osteoporosis. Therefore, the development of anti-resorptive agents has still gained more interest. In this study, using cell-based assay systems in RAW264.7 murine macrophage cells, we found that baicalein significantly inhibited the receptor activator of NF-kappaB ligand (RANKL)-induced tartrate-resistance acid phosphatase (TRAP) activity and the formation of multinucleated osteoclasts in a dose-dependent manner. Interestingly, baicalein inhibited RANKL-induced activation of signaling molecules (Akt, ERK/MAP kinase and NF-kappaB) and mRNA expression of osteoclast-associated genes (TRAP, matrix metalloproteinase 9 and c-Src) and another transcription factors (c-Fos, Fra-2 and NFATc1). In addition, baicalein inhibited the bone resorptive activity of mature osteoclasts by inducing apoptosis. The inhibitory effects of baicalein on the formation of mouse bone marrow macrophage-derived osteoclasts and their bone resorptive activity were also observed. In conclusion, although further studies are needed to determine its biological efficacy and precise mechanism in bone, the present results demonstrated that baicalein has a potential to inhibit osteoclast differentiation and induce mature osteoclast apoptosis.

Lee SU, Shin HK, Min YK, Kim SH. · Department of Biology, School of Bioscience and Biotechnology, Chungnam National University, Daejeon 305-764, Republic of Korea. · Int Immunopharmacol. · Pubmed #18387517 No free full text.

Abstract: Emodin is a naturally occurring anthraquinone present in the roots and bark of numerous plants of the genus Rhamnus. Here, we identified emodin as one of compounds activating the mRNA expression of bone morphogenetic protein (BMP)-2 in the differentiation process of mouse osteoblastic MC3T3-E1 subclone 4 cells. Without any effect on cell growth, the low concentration (up to 5 microM) of emodin highly induced the mRNA expression of BMP-2, the expression of alkaline phosphatase (an early marker of osteoblast differentiation), and the mineralization. Interestingly, emodin induced the activation of phosphatidylinositol 3-kinase (PI3K), Akt and mitogen-activated protein (MAP) kinases, but those inductions by emodin were completely inhibited by the PI3K inhibitor, LY294002, suggesting that the up-regulation of BMP-2 by emodin could be mediated through the activation of both Akt and MAP kinases by activating PI3K. Additionally, emodin-induced activation of NF-kappaB suggested that NF-kappaB might be required for its anabolic activity in part. In conclusion, the use of natural compounds with anabolic activity such as emodin could have a beneficial effect on bone health and this kind of studies further elucidate the pharmacological roles of natural compounds in the prevention of osteoporosis and provide the initiative in the early drug discovery and development for osteoporosis.