lets make clear the things that are NOT leading to immortality. some methods are futile, in my personal opinion anyhow, based on what i have learned so far. i’m not saying i won’t change my opinion when i learn something cardinally new about the advances in these methods. i prefer not to talk in absolute terms.. if i was to claim that i know everything then that would mean i have become hardened in my views, and with this i would become disposable by nature as a not evolving organism. but based on what i have learned so far i can tell that the following methods of achieving longer life are a far cry from achieving immortality — these can be supporting techniques though..
nutritional restriction. you can prolong life with restricting calories, yes, that’s proven, but not indefinitely. in theory you could almost stop metabolism by going into hibernation, as some animals do. you could also let you to be frozen with liquid nitrogen (cryopreservation) and in theory to do it over and over again, living let say few months in every few thousand years.. to look around and go to deep freeze again. or to go into biological hibernation with the same ends. but that’s not really a prolongation of life — it’s rather living in shorter bits over a longer period of time. if you just slow down metabolism and stay active you will keep aging.. far from rejuvenating your body with new, healthy cells.
replacing body parts with newly grown organs has its limits too.. because you cannot replace brain. if you grow a new brain then you’ll have no old memories and it won’t be you anymore.
replacing body parts with robotic non biological technologies and uploading brain functions (mind) into a computer won’t be the life as we know it, obviously. nobody knows if that’s possible to enjoy the life then, to be self aware.