I read an article the other day about a women who lived a long life, and then died having only two stem lines left for her immune system. That's the loss off a lot of diversity.
Blood of world's oldest woman hints at limits of life
If true then white blood cells, which have the unique ability to squeeze into tissues and organs and between cells without damaging them, could represent the universal "Stem" cell repair mechanism that pervade our bodies and performs not only immune protection, but regeneration in every tissue of the body.
Aging might just represent the loss of the ability to regenerate over time.
All cells obey the Hayflick Limit, which until relatively recently wasn't understood, to be the result of repeated cell division that chipped away a little at a time from the end of the DNA strands in each cell, the ends are called Telomeres.
Somewhat akin to the interstitial "gap" required between information sequences in a "frame" of data. Once it erodes away, the information between frames becomes mixed and corrupted.. quite literally "exposing" the Gene sequences to unprotected and unlimited corruption.. so the cell stops dividing and essentially dies. It is a noble death however, since unrestricted growth without control is the hallmark of cancer. Cancer is a curious phenomena though, since it seems only specific "accidents" lead to the familiar patterns of cancer that we know of today.. there don't appear to be an infinite diversity of cancers.. but rather limited classes.. suggesting they may depend on opportunistic "junctions" where Telomere erosion fails to initiate a failure to continue to replicate. Ultimately cancer treatments may develop which target these "junctions" recognizing they have been "jumped" or violated and used as demolition "markers" for White cell lines programmed to target cells with these conditions.
I rather like to think the old Star Trek: Enterprise - "Dr. Flox" (Memory Alpha)
replicating the "cyto-lytic" enzymes referred to custom making a therapy from a patients White cell lines to target such "junctions" and thereby deliver the treatment to those specific cells no matter how deep in the body, and only to those cells.. special delivery "the gift of death" to those that should have died the noble death so that the person might live, but through chance were unable to. (note: scientists are getting very close to this type of Science Fiction, targeting the removal of the HIV genome from human cells, and vaccinating white cells from infection)
When you think of it White cells are amazing.. the ultimate scalpel and hypodermic.. able to go anywhere.. without harm.. and able to do anything necessary. Radiation beams and Chemotherapy seem incredibly harsh and overbearing by comparison. If only we could guide them in the right direction.
And if this be true of cancer.. someday.. in ourselves.. or generations to come.. we might be able to selectively remove these dangerous junctions.. or shore them up with booby-traps and trip-wires in the DNA code itself as In-trons which protect.. or call for assistance from White cells to eradicate and prevent cancer.
One theory of aging is its the "end" to replication, or "regeneration" which leads to degeneration of organ tissue and we literally "fall apart" until a catastrophic condition occurs.. a critical artery bursts, in the wrong place at the wrong time.. plaque builds up because normal repairs fail, and a secondary backup system that relies on "plaque" as if it were household "spackling paste" seals an old wound, or a deficit, the surrounding cells can no longer repair.
When you think of it, aging might be a merciful slow death.. as opposed to a quick, sudden and tragic death.. it may be an experiment in biology that has extended our lives.. if only for a little while.
White blood cells with their unique ability to squeeze almost anywhere in their relentless pursuit of germs and bacteria, even rogue cells that have become cancerous, may as "Stem" cells differentiate into other types of cells like organ cells and act is a secondary if not primary method of making repairs throughout the body. Certainly once organ cells reach the Hayflick Limit.. something, anything.. must be done to regenerate the tissue or we would die immediately.. rather than degenerate at a slower pace. It could be the many White cell Stem cell lines are providing this function.
Reducing their number and diversity is surely a measure of aging, as they undergo many divisions in their constant assault from everyday life. The more often we are sick, probably the fewer White cell Stem cells lines are left.. shortening our lives. Inflammation has been blamed for this, but the site of inflammation is also the site of the most White cell activity. A marker they are being "used up".
Looking at it this way, I can see all of the organs and cells of the body are constantly being eroded by the activity of life.. like sand paper.. the sands of time wear us down.
Diabetes for example must be a lot like this, assuming the Type 2 which appears to be a result of life style more than a mystery. The accelerated introduction of high blood sugar, ( whether by diet, disease or anything that provokes a higher than normal blood sugar level.. must "wear" the Islets of Langerhans down. I would imagine exposure to some pathogens or diseases can wear them down faster than others and contribute to a cumulative reduction in pancreatic blood sugar control.
This might also explain life extension through deliberate calorie deficit. I always thought it was the principal of.. the less chemical reactions per cell.. the less "that can go wrong" even if something like cancer were inevitable.. it would on average take longer to actually occur. But this new line of thought brings to light, a calorie deficit may simply not "grind" our cells down into the dust as fast.. so living fast leads to a short life.. living slow.. leads to a long life.. as a mantra, kind of makes sense, in multiple ways.
We've never really had much of an opportunity to "over consume" and in "selective ways" the foods that give us the most pleasure and manipulate our brain chemicals much like addictive drugs in all of history. But for now, we can.. and a grand experiment is underway.. perhaps even a Darwinian process of weeding out entire familial lines that cling to convenience.. or some type of belief that leads them to control, not just diet and lifestyle.. but the rate of exposure to infectious disease.. and perhaps even controlling sleep patterns and "chosen" patterns of exercise. The "have Health" and "Healthy nots". Curious how we use similar reasoning that the choice is not under our control, or too hard and practically uncontrollable like a force of nature. Seems similar arguments applied to Tobacco, Alcohol and recreational drugs at one time of history or another across many cultures.
We still are not at that point when monitoring our blood glucose levels is delegated and taken care for us minute by minute.. such that we don't have to think about it.. but with things like the bloodless Grove Instruments meter.. and the Google contact lenses that measure those things perhaps that day will be coming soon. I truly wonder then.. when we do have the choice and its relatively easy.. will this extend human life.