HMOX1 and chronic obstructive pulmonary disease: Treatment of fibroblasts from COPD patients with hemin to activate HO-1 results in reduced cellular senescence, improved mitochondrial function, and reduced ROS production [122] Since Nrf2 activates many other antioxidant genes in addition to HO-1, this suggests that activators of Nrf2 and inhibitors of Keap1 might be even more effective against oxidative stress in COPD.