Humanin, a component of this group, enhances mitochondrial biogenesis and mtDNA copy number, counters endoplasmic reticulum stress, and suppresses ROS-related cell death by STAT3 phosphorylation and caspase-3 activation [459, 460].An investigation on AMD cybrids revealed that humanin preserves AMD mitochondria, reducing pro-apoptosis agents and enhancing protection against amyloid-β-induced damage [461]. Here, STAT3 is linked to age-related macular degeneration.