**3.9 PON2 and age**

Expression of PON2 decreases with age. Thus, with growing age, the susceptibility to oxidative damage is increased, in turn increasing the risk for neurodegenerative diseases. In mice, concurrent to PON2 deficiency, transcripts of glucose transporter 4, insulin receptor and tau were upregulated, while butyrylcholinesterase was significantly downregulated, potentially having neurodegenerative consequences. However, the findings supported a lack of oxidative stress in the aged brain with potential impacts to endogenous signaling and host immunity through a reduction in cytokine expression [73].
