There's a great diversity in lifespan among organisms, which is a good clue, but the number of organisms that actually show no senescence is quite small, and they are all very distant from humans evolutionarily.
Those few have been studied heavily in aging, but trying to extrapolate differences in these organisms to humans is very challenging because they have totally different anatomies, genomes, and sets of proteins. Plus, lifespan is very multifactorial; for example, you can "extend lifespan" in many species by inhibiting cancer, but that isn't really stopping aging per se.
It's hard for many reasons, but I think the most important one is that we have no good mathematical or experimental tools for understanding and predicting how a given perturbation (drug, diet, etc) will affect a hugely complex network of 25K+ transcripts. Or how those transcripts affect each other causally. In a variety of tissues. And genetic backgrounds. And in the context of longer-term changes like epigenetic changes and DNA mutation.
Another huge problem is that lifespan studies take, well, lifetimes. So we usually do them in organisms like worms and flies, which are very different from humans.
Those few have been studied heavily in aging, but trying to extrapolate differences in these organisms to humans is very challenging because they have totally different anatomies, genomes, and sets of proteins. Plus, lifespan is very multifactorial; for example, you can "extend lifespan" in many species by inhibiting cancer, but that isn't really stopping aging per se.
It's hard for many reasons, but I think the most important one is that we have no good mathematical or experimental tools for understanding and predicting how a given perturbation (drug, diet, etc) will affect a hugely complex network of 25K+ transcripts. Or how those transcripts affect each other causally. In a variety of tissues. And genetic backgrounds. And in the context of longer-term changes like epigenetic changes and DNA mutation.
Another huge problem is that lifespan studies take, well, lifetimes. So we usually do them in organisms like worms and flies, which are very different from humans.