A short while ago I mentioned a Filter of Decrepitude (blood plasma dilution has a beneficial effect). This keeps turning over in my mind . . .
I was reflecting on the positive results from the dilution of plasma study.
When I describe this to other people I have come to rely on an analogy to automotive technology. As an engine or transmission operates you get metal-sliding-on-metal generating minuscule shavings. Even with lubrication. (there are also chemical changes with aging and over heating that cause the lubricant to become less effective)
These shavings are present in the lubricant and over time the loading increases if the fluid is not replaced. At some point this material in the lubricant begins to turn the lubricant into a slurry with abrasive quality. That wears the metal parts down faster increasing the metallic debris loading in the fluid which increases the wear which increases the shavings load . . . at some point it’s almost like a positive feedback loop and speed of wear and degradation accelerates.
Of course that’s not how the immune system works but it gets a certain picture of creeping decrepitude into their heads and I follow that up with this:
Of course your body isn’t metal but what does happen with age and living is the cells breakdown and you get cellular debris. Fragments of cell walls floating around. Worse is the biochemical constituents from inside the cells – some of those are damaging to other cells if they are floating around and able to touch outer cell walls of other cells.
So we get an increasing loading of the debris of cellular destruction and whatever other chemicals might be wrongly generated by incorrectly operating systems within our bodies. By that I mean the byproducts of life style choices or disease that produce inflammation which damages more cells. Hormones gone wrong. Organs malfunctioning. Over consumption of the wrong materials.
Now think about that from the immune system’s point of view.
Here’s a list of things that change with our immune system as we get older (courtesy of livescience.com Aging Lowers Your Immunity.)
- The thymus, which is located behind the breastbone, is one of the organs of the immune system. The thymus is where immune cells, white blood cells, called T lymphocytes (T cells) mature. The thymus begins to shrink when we are young adults. By middle age it is only about 15 percent of its maximum size.
- Some T cells kill antigens directly. Others help coordinate other parts of the immune system. Although the number of T cells does not decrease with aging, T-cell function decreases. This causes parts of the immune system to weaken and increases the risk for becoming ill.
- Macrophages, which are white blood cells that ingest antigens, don’t work as quickly as they used to. This slowdown may be one reason that cancer is more common among older people.
- There are fewer white blood cells capable of responding to new antigens. Thus, when older people encounter a new antigen, the body is less able to remember and defend against it.
- The amount of antibodies produced in response to an antigen is less in older people, and the antibodies are less able to attach to the antigen. These changes may partly explain why pneumonia, influenza, infectious endocarditis, and tetanus are more common among older people and cause death more often. These changes may also partly explain why vaccines are less effective in older people.
- Later in life, the immune system also seems to become less tolerant of the body’s own cells. Sometimes an autoimmune disorder develops; normal tissue is mistaken for non-self tissue, and immune cells attack certain organs or tissues. Among the autoimmune disorders are: lupus, rheumatoid arthritis, scleroderma and ankylosing spondylitis.
- Diabetes, which is also more common with increasing age, can also lead to decreased immunity.
Now that list shows a number of things that change with your immune system over your lifetime. If we use the analogy of a defensive army fighting off invaders we could say that over time the army shrinks, the soldiers aren’t as well trained or effective. Conversely the field of enemies that army faces increases.
As the army loses more fights there’s more cellular debris floating around from the damage those fights caused. The more debris there is the busier the immune system becomes trying to filter the chemical signals that warn of invaders from those of the debris. It’s gets swamped with all the work. Increasing work load on a decreasing, and less effective, defense system means at some point it cannot keep up and you get a major infection that kills the body or a cascading set of failures that cannot be stopped.
In that list above they mention “T-cell function decreases”.
I am curious if they have measured this with actual individual cells OR if they know this from statistical studies of immune systems functionality? Because the former means we know the cells are less effective on an intrinsic level but the latter might mean they are still individually effective but the growing onslaught of detritus they face blunts that effectiveness.
They also point out “Macrophages, which are white blood cells that ingest antigens, don’t work as quickly as they used to”. I ask the same question as I do for the T-cell functionality. Do we know that for sure or is it a deduction from bulk activity not measuring up to statistical predictions?
Another thing mentioned is “Later in life, the immune system also seems to become less tolerant of the body’s own cells”. I wonder if an increasing loading of cellular debris presents to the immune system an ever expanding palette of cellular components that it needs to analyze and decide which are self and which hare not-self. Breakdown the cellular machinery enough and at some point the contents of self cells and the contents of non-self cells starts to look more alike than different. Possibly the aging immune system gets confused because of this and slips into attacking certain self cells via a ratcheting that way over time.
So could it be that the process of diluting the plasma and reintroducing it into the mouse is helpful simply because it reduces the amount of material the mouse’s immune system has to face in order to do its job? Akin to changing the oil in your car?
I’m just following logical-sounding questions along a path of inquiry. I have no lab or training that would allow me to say I know with any certitude that this is what happens but I do wonder about it seeing as I’m approaching that immune system cliff (hopefully not too quickly).