Last week a group of US scientists published the first observation of the interstice of our tissues. It's suspected that it's either in all or in almost all the tissues of our body, located under our skin, under the walls of the stomach, the walls of the intestine, in the lungs, in the wall of the arteries and veins, in the pancreas and in a lot of other places. Practically everywhere in our body.
Its appearance is something curious, a kind of cobweb made with collagen and full of liquid in all its intermediate spaces.
How does blood get into all our cells?
Easy, through the blood vessels that run through our body but no arteries reach all the cells. The arteries branch out, get smaller and smaller. The smaller ones are called capillaries. Basically what the circulatory system does is release this charge between the cells and wait for the cells to pick it up by themselves. This charge carries sugar and oxygen among other substances.
Cells lives in a kind of continuous bath of a liquid provided by the blood and that liquid is what feeds them and is also the one that deals with getting rid of the waste of the cells. This fluid is called "interstitial fluid", 90% of this fluid re-enters the venous capillaries, continues through the veins and continues its way through the circulatory system but there is a 10% who can't return and stays in the middle of the cells stagnantly.
This stagnant liquid is collected by the lymphatic system, the lymphatic system is also throughout our body and what it does is channel this interstitial fluid and ends up returning it to the healthy blood and once it has already been collected.
This interstice that has been discovered is the intermediate point between the tissues and the lymphatic vessels. Until now it was assumed that this interstitial fluid moved between the cells reaching the lymphatic vessels but it had never been seen how this happened.
Now we know that all this excess liquid that's between the cells ends accumulated in this cobweb of collagen and that it is under a great part of the tissues of the body and it seems that from there the lymphatic vessels are collecting it, channeling it and carrying it where they have to take it.
How come it hasn't been seen so far if it's in all our tissues?
Good question. It turns out that it can only be seen in living tissues or in tissues that have been frozen immediately after removal because the structure it has (structure in a liquid-filled web), the moment it's touched, all the liquid escapes and then the web sticks and forms a kind of collagen substance that cannot be seen.
The tumor cells use this interstice to enter the lymphatic system through a back door to reach the rest of the body. Maybe the metastasis starts in this structure and maybe, if we could understand it better, we could make life more difficult for the cancer.