A great many researchers are presently engaged in amassing data on human longevity. There are the longitudinal studies running for decades, familial studies searching for measures of inheritance in long-term health, the vast statistical epidemiological studies, and behind them all the growing databases of various biological measurements, taken in ever greater detail as the costs of doing so fall rapidly. This is all very interesting, and will ultimately lead to a complete (and very, very complex) vision of how human metabolism runs and alters throughout aging, from the uppermost and more familiar processes all the way down to cellular mechanisms and accrued damage.
But strangely, very little of this is strictly necessary in order to engineer far longer lives. We don't need to know much more than we do already about human biology in order to have a good shot at building functional rejuvenation biotechnologies. The differences between old tissues and young tissues are pretty well enumerated at this time: the remaining lack of knowledge relates to the (many, many) details of the intricate dance of molecular and epigenetic mechanisms involved in moving from young to old. That dance is what the majority of the aging research community - and the majority of funding - is involved in deciphering. But anyone with a bunch of money could short-cut all of that and stomp right down the path to rejuvenation therapies today, if they cared to do it. All that needs to happen is that the known differences between old tissue and young tissue be repaired - it doesn't matter how it happens, so long as you can repair it.
Think of it this way: a man could spend a very long time building the mathematical models needed to show exactly how paint cracks and flakes on a wall. In doing that he might learn a lot about how to create paint that lasts a little longer, or which materials make for longer-lasting painted surfaces. That's a life's labor right there. Or he could just take a day every now and then to sand off the wall and paint it over. This is essentially the same comparison between the relative amounts of labor involved in aging and longevity science - with the note that in this analogy the man needs to create the paint from scratch and chase down a horse and a tree to make the brush.
So longevity science is as much a matter of persuasion as getting the work done. We need to see more funding going to repainting and less to the general theory of decay in painted surfaces. It's very clear what needs to happen, but gathering the necessary large-scale funding for work on SENS-like rejuvenation biotechnology is a work in progress.
In any case, here's an interesting pair of papers resulting from some of the ongoing studies of human aging. Interesting doesn't necessarily mean progress towards longer lives, remember, but there's no harm in looking and learning. This first one, for example, makes one think about damage-based theories of aging - with the implication that people who live longer tend to be more robust in every way at every age, precisely because they are carrying less of a burden of damage. It is also worth looking back at unrelated work that speculatively suggests that intelligence (or better cognitive function, take your pick) correlates with longevity for genetic reasons rather than sociological or economic reasons. i.e. genes for intelligence confer greater resistance to low-level damage in cells and molecular machinery.
Decline in cognitive performance is a highly prevalent health condition in elderly. Offspring of nonagenarian siblings with a familial history of longevity have better cognitive performance compared to the group of their partners of comparable age. This effect is independent of age-related diseases and known possible confounders. Possible explanations might be differences in subclinical vascular pathology between both groups.
And here is another in a line of papers noting that long-lived humans appear to be subtly different in their lipid metabolism. These lipid metabolism differences are among the few that have been reliably showing up in different populations.
Here using a combined metabonomics approach [we] report for the first time the metabolic phenotype of longevity in a well characterized human aging cohort compromising mostly female centenarians, elderly, and young individuals. With increasing age, targeted [profiling] of blood serum displayed a marked decrease in tryptophan concentration, while an unique alteration of specific glycerophospholipids and sphingolipids are seen in the longevity phenotype. We hypothesized that the overall lipidome changes specific to longevity putatively reflect centenarians' unique capacity to adapt/respond to the accumulating oxidative and chronic inflammatory conditions characteristic of their extreme aging phenotype.