NO Deficiency and HIF-1a6 Stabilization in HUVECs 42. Valerio A, Cardile A, Cozzi V, Bracale R, Tedesco L, et al. (2006) TNF-alpha downregulates eNOS expression and mitochondrial biogenesis in fat and muscle of obese rodents. J Clin Invest 116: 2791–2798. 43. Barrientos A, Fontanesi F, D´ıaz F (2009) Evaluation of the mitochondrial respiratory chain and oxidative phosphorylation system using polarography and spectrophotometric enzyme assays. Curr Protoc Hum Genet Chapter 19: Unit19.13. PLoS ONE | www.plosone.org 11 December 2011 | Volume 6 | Issue 12 | e29680