Aim: Sarcopenia and sarcopenic obesity are significant associative factors for functional impairment related to aging. The main aim of the present study was to investigate the prevalence of sarcopenia and sarcopenic obesity, and their associations with functional status among men aged 80 years and older in Beijing.Methods: A total of 75 young healthy volunteers, and 101 older men aged 80 years and older participated in the present study. Demographic characteristics, anthropometry, skeletal muscle mass measured by dual X-ray absorptiometry (DXA), 6-m gait speed and handgrip strength were collected. Relative appendicular skeletal muscle index (RASM) and percentage skeletal muscle index (SMI) were obtained. Results:Overall, the prevalence of sarcopenia was 45.7% by using RASM. By the weight-adjusted skeletal muscle index definition (SMI), the prevalence of sarcopenia was 53.2%. The prevalence of sarcopenic obesity was lower by using RASM than SMI (4.9% vs 11.5%, P < 0.05). When we compared the sarcopenia prevalence (%) in obese participants, it was also remarkably lower by using RASM (40.0%) than SMI (95.0%). By using either RASM or SMI, gait speed was of no significant difference among the pure sarcopenia group, pure obese group and sarcopenic obesity group (0.76 ± 0.27 vs 0.82 ± 0.37 vs 0.82 ± 0.27 m/s, P > 0.05, by RASM; 0.75 ± 0.25 vs 0.92 ± 0.27 vs 0.82 ± 0.35 m/s, P > 0.05 by SMI), respectively. Multiple linear regression analyses showed that thigh skeletal muscle mass was positively correlated with gait speed independently (β = 0.221, P = 0.011), and total body fat (β = −0.216, P = 0.002) and age (β = −0.524, P = 0.000) were negatively correlated with gait speed independently. Conclusions:The prevalence of sarcopenia is high either based on RASM or SMI among Chinese men aged 80 years and older. Functional limitations were significantly associated with older age, skeletal muscle mass and total body fat. Geriatr Gerontol Int 2014; 14 (Suppl. 1): 29-35.

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Bone remodeling balance is maintained by tight coupling of osteoblast-mediated bone formation and osteoclast-mediated bone resorption. Thus, agents with the capacity to regulate osteoblastogenesis and osteoclastogenesis have been investigated for therapy of bone-related diseases such as osteoporosis. In this study, we found that wedelolactone, a compound isolated from Ecliptae herba, and a 9-day incubation fraction of conditioned media obtained from wedelolactone-treated bone marrow mesenchymal stem cell (BMSC) significantly inhibited tartrate-resistant acid phosphatase (TRAP) activity in RANKL-stimulated osteoclastic RAW264.7 cells. Addition of the semaphorin 3A (Sema3A) antibody to the conditioned media partially blocked the medium’s inhibitory effects on the RAW264.7 cells. In BMSC, mRNA expression of Sema3A increased in the presence of different wedelolactone concentrations. Blocking Sema3A activity with its antibody reversed wedelolactone-induced alkaline phosphatase activity in BMSC and concurrently enhanced wedelolactone-reduced TRAP activity in osteoclastic RAW264.7 cells. Moreover, in BMSC, wedelolactone enhanced binding of Sema3A with cell-surface receptors, including neuropilin (NRP)1 and plexinA1. Furthermore, nuclear accumulation of β-catenin, a transcription factor acting downstream of wedelolactone-induced Sema3A signaling, was blocked by the Sema3A antibody. In osteoclastic RAW264.7 cells, conditioned media and wedelolactone promoted the formation of plexin A1-NRP1, but conditioned media also caused the sequestration of the plexin A1-DNAX-activating protein 12 (DAP12) complex and suppressed the phosphorylation of phospholipase C (PLC)γ2. These data suggest that wedelolactone promoted osteoblastogenesis through production of Sema3A, thus inducing the formation of a Sema3A-plexinA1-Nrp1 complex and β-catenin activation. In osteoclastic RAW264.7 cells, wedelolactone inhibited osteoclastogenesis through sequestration of the plexinA1-DAP12 complex, induced the formation of plexinA1-Nrp1 complex, and suppressed PLCγ2 activation.