To better understand autophagy dynamics after TBI, we measured the immunoreactivity of CTSD (Cathepsin D, a lysosomal protease) [39], LAMP1 (Lysosomal-associated membrane protein 1, a regulator of lysosomal integrity, pH and catabolism) [2, 20, 115], and p62 (an autophagic substrate) [82] in mouse models of TBI and post-mortem human brain tissue with TBI history and AD. The gene discussed is CTSD; the disease is Alzheimer disease.