Off the top of my head, here are some guesses for possible toxins that could accumulate: 1) Advanced Glycation End-productions (AGE) from normal metabolism 2)

Off the top of my head, here are some guesses for possible toxins that could accumulate: 1) Advanced Glycation End-productions (AGE) from normal metabolism 2) Trace levels of heavy metals, dioxins, etc. from the growth media 3) Reactive oxygen species (ROS) generation increasing with age-related damage 4) BPA, phthalates, or other potentially nasty things leaching from the plastic growth containers 5) Lipofuscin 6) Misc age-related inflammatory cytokines 7) ????