Insterstitium, the rediscovery of the connective tissue system of the body

A new study by researchers from NYU School of Medicine pathologist reveals, what we already know, that there are layers of interconnected, fluid-filled compartments  below the skin’s surface, which line the digestive tract, lungs and urinary systems, and surrounding arteries, veins, and surround the muscle.

A meshwork of strong (collagen) and flexible (elastin) connective tissue proteins supported this network. They may act like shock absorbers that keep tissues from tearing as organs, muscles, and vessels squeeze pump and pulse.

While this discovery from medicine has attracted lots of media hype and attention, Gil Hedley has shown it a while ago and called the Fuzz, and recently he termed it perifascia. Dr. Jean-Claude Guimberteau also has shown this network in his endoscopic study Strolling under the Skin, which he called the Multimicrovacuolar Collagenic Absorbing System, MVACS, a network of collagen fibrils forming microvacuoles that appeared to be randomly organised but can adapt itself to various stress.

This new study finding is based on a newer technology called probe-based confocal laser endomicroscopy, which combines the slender camera-toting probe or an endoscope equipped with a laser that lights up tissues, and sensors that analyse the reflected fluorescent patterns. It offers a microscopic view of living tissues.

The researchers found this system during their study of bile ducts from twelve cancer surgeries through the endo-microscope. The team then recognized this new space occurs throughout the body, wherever tissues moved or were compressed by force. The cells lining the space are also unusual, perhaps responsible for creating the supporting collagen bundles around them. The cells may also be mesenchymal stem cells, which are known to be capable of contributing to the formation of scar tissue seen in inflammatory diseases. Lastly, the protein bundles seen in the space are likely to generate electrical current as they bend with the movements of organs and muscles and may play a role in techniques like acupuncture said the authors.

The authors further speculated that the finding that this layer is a highway of moving fluid might explain why cancer that invades it becomes much more likely to spread. Draining into the lymphatic system, the newfound network is the source of lymph, the fluid vital to the functioning of immune cells that generate inflammation. Furthermore, the cells that reside in the space, and collagen bundles they line, change with age and may contribute to the wrinkling of skin, the stiffening of limbs, and the progression of fibrotic, sclerotic and inflammatory diseases.

The authors called this network interstitium as an organ in its own right. As the human body is about 60 percent water, about two-thirds of that water is found inside cells, but the other third is “interstitial” fluid.

While this news has created a new excitement of fascia, many fascia researchers were frustrated that there are already a lot of studies on the connective tissue system and discussed in length at the Fascia Research Congresses which were entirely ignored by the paper. The only good news is that the connective tissue system is now widely recognised.

 Schematic of the fluid-filled space supported by a network of collagen bundles lined on one side with cells. From Benias et al. 2018 CC-by-ND