The activity of the AMPK-Nampt-Sirt1 axis is decreased in the advanced heart failure. (A) H9c2 cells were treated with compound C at indicated concentrations and cultured for 24 hours. Cell lysates were subjected to immunoblot analyses with anti-AMPK, anti-Nampt, anti-Sirt1 and anti-tubulin. The results shown are one representative of four independent experiments. (B) Atrial myocardial homogenates were prepared from the heart recipient and donor patients, respectively. Expression of phospho-AMPK(Thr172), AMPK, Nampt, and tubulin was evaluated by immunoblots. The level of donor heart is expressed as 1. Representative immunoblots were shown. (C) Heart homogenates were prepared from C57/B6 mice aged 1 week, 1 month, 3 months, and 12 months. Expression of phospho-AMPK(Thr172), AMPK, Nampt, Sirt1, MnSOD and tubulin was evaluated by immunoblots, and the level of phospho-AMPK/total AMPK, Nampt, Sirt1, and MnSOD was compared between 3-month (expressed as 1) and 12-month mice.