A recent report in a Nature journal here talks about the discovery that many structures previously thought to only have a structurally supportive role, including the submucosae of the entire gastrointestinal tract and urinary bladder, the dermis, the peri-bronchial and peri-arterial soft tissues, and fascia, contain a sponge like interconnected network though which interstitial fluid can pass within and between organs before passing into the lymphatic system. The change to our understanding is so profound that scientists are suggesting this might warrant being being described as a new organ, so what is its significance? Simple answer, we don't know. The fluid may act as a shock absorber. Interestingly, the interstitium seems concentrated around structures that are subject to rhythmic or intermittent compression, this perhaps suggests that the fluid contained within is intended to be pumped around. Unlike the lymphatic system, which is similar and connected, the interstitium doesn't contain large numbers of immune cells but it does appear that they can enter to fight threats. There are many interesting questions about its purpose, function and whether it can go wrong, not least whether it is an important method of cancer metastasis, or indeed can be used as a useful tool for diagnosing and tracking cancer spread. As an osteopath, this is particularly interesting as any structure that uses movement is potentially something we can influence.
Picture copyright Jill Gregory / Mount Sinai - http://www.jillkgregory.com/
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