These catabolic processes were mediated by increased intracellular oxidative stress and activation

of p38 MAPK. Pretreatment with the antioxidant N-acetyl-cystein (NAC) and inhibition of p38 MAPK prevented cigarette smoke-induced catabolism in C2 myotubes. Based on the above studies and our recent findings, we have suggested a cellular model of cigarette smoke-induced skeletal muscle catabolism.9 In this model, components Inhibitors,research,lifescience,medical of cigarette smoke may reach skeletal muscle of smokers, leading to increased oxidative stress and activation of signaling pathways which trigger up-regulation of muscle-specific E3 ubiquitin ligases. As a result, degradation of skeletal muscle protein is increased and the progression of sarcopenia in elderly smokers may be accelerated.9 CONCLUSION Lifestyle habits regarding nutrition, physical activity, exercise, alcohol consumption, and tobacco use have a substantial impact on the progression of sarcopenia and the ability to prevent and treat the loss of muscle mass and function in old age. As Inhibitors,research,lifescience,medical life expectancy is increasing worldwide, the prevalence and costs of sarcopenia are expected Inhibitors,research,lifescience,medical to rise. In order to treat and delay sarcopenia, the choices we make in our lifestyle habits must be taken into consideration. In contrast

to physiological and systemic changes that occur in our body as we age and accelerate the progression of sarcopenia, lifestyle factors Inhibitors,research,lifescience,medical are far more controllable. Therefore, raising the public awareness regarding the importance of lifestyle habits on the status of skeletal muscle in old age is of great importance in the management of sarcopenia. Acknowledgments This study was supported by grants from the Rappaport Institute, the Krol Foundation of NVPLDE225 Barnegat N.J., the Myers-JDC-Brookdale Inhibitors,research,lifescience,medical Institute of Gerontology and Human Development, and ESHEL—the association for planning and development of services for the aged in Israel. Abbreviations: BMI body mass index; DEXA dual energy X-ray absorptiometry;

EAA essential amino acid; ERK1/2 extracellular signal-regulated kinase 1 and 2; EWGSOP European Working Group on Sarcopenia in Older People; HMB β-hydroxy-β-methylbutyrate; IGF-1 insulin-like growth factor-1; MAFbx/atrogin-1 muscle atrophy F-box; MAPK mitogen-activated protein kinases; mTOR mammalian target of rapamycin; MuRF1 muscle ring finger 1; MyHC myosin heavy chain; PRT progressive resistance training; RDA recommended dietary Sodium butyrate allowance. Footnotes Conflict of interest: No potential conflict of interest relevant to this article was reported.
HIV/AIDS came to the world’s awareness over 30 years ago, with the first reports of young homosexual men, considered to be previously healthy, suffering from various types of opportunistic infections and profound cellular immunodeficiency.1 In the relatively short time since then, it has grown in scale to become a worldwide epidemic, with an estimated number of 34 million people living with HIV by 2011.