Interestingly, lithium does seem to protect telomeres and in fact lengthens them, which may affect Alzheimer's.
IIRC the hypothesis is that lithium orotate does not fully dissociate in water and thus can cross the blood brain barrier much more easily than plain Li+, and then the cells in your brain can take up the lithium orotate, metabolize the orotate part, and make the free Li+ available.