Weight increase and overweight are associated with DNA oxidative damage in skeletal muscle
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Background and aims: Weight maintenance within normal standards is recommended for prevention of conditions associated with oxidative injury. To compare oxidative damage in a post mitotic tissue, between adults differing in long-term energy balance. Methods: During hernia surgery, a sample of skeletal muscle was obtained in 17 non-obese adults. Subjects were divided into two groups according to their self-reported weight change: weight maintainers (WM) reported < 4kg increase, and weight gainers (WG) reported > 5 kg increment. Muscle immunohistochemistry for 8-hydroxy-deoxyguanosine (80HdG), 4-Hydroxy-2-nonenal (4HNE), and TNF-alpha, as markers of oxidative injury and inflammation, were performed. As known positive controls for oxidative injury, we included 10 elderly subjects (66-101 yr). Anthropometric measures and blood samples for clinical laboratory and serum cytokines (TNF-alpha and IL-6) were obtained. Results: 80HdG was higher in WG compared with WM (149.1 +/- 16.2 versus 117.8 +/- 29.5, P = 0.03), and was associated with anthropometric indicators of fat accumulation. 4HNE was similar in WG compared with WM (10.9 +/- 7.6 versus 9.8 +/- 6.3) but noticeably higher in elderly subjects (21.5 +/- 15.3, P = 0.059). TNF-alpha protein in WG was higher compared with WM (114.0 +/- 41.7 versus 70.1 +/- 23.3, P = 0.025), and was associated with weight increase. Conclusions: Moderate self-reported weight increase, and body fat accumulation, suggesting long-term positive energy balance is associated with muscle DNA oxidative injury and inflammation.