A clear differentiation follows from Groves:
On 2 Apr 1995, Andrew K. Groves wrote:
> In article <-EwfvAeABh107h at chambers.ak.planet.co.nz>,
>steve at chambers.ak.planet.co.nz (Steve Chambers) wrote:
>>> > There's a tendency for those of us who've spent most of our studies
> > in cellular and molecular biology to think that the term senescence
> > (and by implication aging) only applies to cells. It doesn't - and
> > for most of the community the terms apply principally to whole
> > organisms.
>> I agree. But the reason why much work has been done on cells is that they
> represent a relatively simple way of examining the control of cell
>>> > The processes that dictate the "lifespan" of a cell or clone are but
> > a small subset of those that should be examined when studying aging.
> > Genetic control is plainly a major factor in cellular senescence but
> > cellular senescence probably doesn't "explain why people die." There's
> > a hackneyed quote in gerontology: "Nobody dies of old skin."
> > You have to ask yourself a question: If current definitions of aging
> > (including one that relies upon cellular senescence) don't "explain why
> > people die" then how useful are they?
>> I would suggest that one reason why we don't understand why people die is
> that we don't understand the mechanisms of even simple systems such as
> fibroblast senescence. You can define a phenomenon, but that is worlds
> away from suggesting that you understand it.
>> Another reason why simple culture models of cell growth are so popular is
> that whilst "Nobody dies of old skin", a lot of people die of cancer, and
> studies on cell division, senescence, transformation and death are a way
> of getting at the molecular mechanisms of such processes.
>> I'm not suggesting for a moment that other ways of thinking about ageing
> are invalid. Quite the opposite. But part of the problem with the
> discussion over the past few days is that people from different
> backgrounds have been arguing about the meaning of concepts such as
> immortality and senescence. Explaining one's own perspective may go some
> way to clarifying the discussion.
> Andy Groves
> Division of Biology, 216-76
> California Institute of Technology