Cell metabolism
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Osteoporosis results from an imbalance between bone resorption and bone formation. While bone resorption inhibitors are widely used to treat osteoporosis, stimulating bone formation is more challenging. Recently, McClung et al. (2014) found that neutralization of sclerostin, a potent inhibitor of bone formation, effectively increased bone mass in postmenopausal women.
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Metformin is the most widely prescribed drug to lower glucose in type II diabetics, yet its mechanism of action remains controversial. A new study reveals that metformin inhibits mitochondrial glycerol-3-phosphate dehydrogenase, triggering reduction of the cytosolic NADH/NAD(+) pool and impaired utilization of redox-dependent substrates for gluconeogenesis (Madiraju et al., 2014).
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The breakdown of cellular fat stores fuels energy production and multiple anabolic processes. Albert et al. (2014) demonstrate that the lack of hormone-sensitive lipase, a member of the enzyme trio that catabolizes fat, has pronounced effects on lipid metabolism, glucose homeostasis, and cell signaling in humans.
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It has been known for some time that blood from young mice can positively impact aged animals, while blood from old mice has the opposite effect. Recent studies report that rejuvenating effects of young blood extend to multiple tissues and have identified GDF11 and CCL11 as factors mediating these effects.
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Fasting has been practiced for millennia, but, only recently, studies have shed light on its role in adaptive cellular responses that reduce oxidative damage and inflammation, optimize energy metabolism, and bolster cellular protection. In lower eukaryotes, chronic fasting extends longevity, in part, by reprogramming metabolic and stress resistance pathways. In rodents intermittent or periodic fasting protects against diabetes, cancers, heart disease, and neurodegeneration, while in humans it helps reduce obesity, hypertension, asthma, and rheumatoid arthritis. Thus, fasting has the potential to delay aging and help prevent and treat diseases while minimizing the side effects caused by chronic dietary interventions.