APP and Alzheimer disease: Bihaqi and colleagues [129] exposed rats to Pb at different life stages and showed that the AD-related genes beta amyloid precursor protein (AβPP), β-site amyloid precursor protein cleaving enzyme 1 (BACE1), and specificity protein 1 (Sp1) were upregulated in elderly rats exposed to the contaminant at an early age, resulting in cognitive impairment later in life.