This is a very good overview of the core challenges and tools available, but I can't help wonder why so many people have this myopic fixation on extending the human lifespan. Most people today are fat and suffering from a wide range of chronic ailments entirely caused by them making atrociously poor lifestyle choices. Life extension merely offers the possibility of people spending even more decades sick, fat, and nearly dead. Worse yet, while most people's bodies are in a terrible state, their brains are in even worse condition. Most people spend their time staring at mindless entertainments on a variety of shiny screens - entertainments which are the mental equivalent of toxic junk food. Why we'd go to the enormous trouble of attempting to extend lives that aren't actually worth living - and thereby incurring additional trillions of dollars in annual health care expenditures - is not at all obvious.
Perhaps if instead of pursuing pointless goals we focused instead on healthspan then we could make some real progress. But as no one seems to care about health, this seems a forlorn hope.