Sometimes, it just takes naming something to crystallize what was obvious all along.
We all know that blood circulates through the body, carrying nutrients and oxygen to the cells, propelled by the heartbeat. About 1/3 of the plasma diffuses through the capillary walls to bathe the cells.
The diffused plasma enters the lymphatic vessels which return it to the blood. Lymphatic vessels go in one direction only - toward the upper chest where the lymph is returned to circulation. Lymph is propelled by muscle movements. (Which is why walking and arm movements help prevent lymphedema.)
But what happens to the lymph between the time it leaves the capillary and the time it enters the lymphatic vessel?
It has always been obvious that the body’s cells don’t stick to each other. They are held in place by a network of collagen which comprises about 25% of the body’s dry weight. The collagen is padded by a gel, comprised of hyaluronic acid. The lymph fluid carrying dissolved oxygen and nutrients must diffuse through this gel to bring the goodies to the cell membranes.
This intercellular matrix has just been dubbed the “interstitium.” A recent experiment shows that dye can migrate through the interstitum as if it was a wet sponge. That’s really not surprising.
It has also been discovered that cancer cells can migrate through the interstitium by breaking down the hyaluronic acid as they swim through it. This adds to the mechanism for metastasis of migrating through the lymphatic system and blood vessels. Research is investigating ways to inhibit the breakdown of hyaluronic acid by cancer cells. @whafa
It’s nice that science is finally paying attention to this long-neglected tissue.
A couple of practical takeaways.
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Don’t get a tattoo. Tattoo inks are not FDA approved but are repurposed industrial dyes from the paint and plastics industry. “Chemical and Engineering News” journal has some blood-curdling articles about this. The inks inflame the immune system and are pulled into the lymphatic system and interstitium. That’s why tattoos fade and become even more hideous than they started.
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As we age, the metabolic process that converts glutamate into proline (a major constituent of collagen) gradually declines. Since we shed our entire skin once a month the collagen must be replaced. If we don’t eat collagen to replace the proline it will be taken out of our bones (which are 40% collagen) or the interstitium. That’s why old people get thinner, wrinkled skin and thin, brittle hair and nails. Not to mention worn joints, tendons and ligaments. This is the reason I eat 2 tablespoons of collagen every day.
Wendy