There has been a bit of buzz on the various news outlets and social media feeds about the “new organ” the interstitium. On March 27th an article appeared in Scientific Reports, an online peer-reviewed journal from the publishers of Nature. This work was presented by a team of researchers that utilized a new in vivo laser endomicroscopy technique that demonstrated this tissue is a matrix of collagen bundles and elastic fibers surrounded by fluid rather than the tightly packed layers of connective tissue that was previously observed on fixed slides . This submucosal layer was observed in the entire gastrointestinal tract, the urinary bladder, bronchus, dermis, bronchus and peri-arterial soft tissue and fascia. The authors state, “In sum, we describe the anatomy and histology of a previously unrecognized, though widespread, macroscopic, fluid-filled space within and between tissues, a novel expansion and specification of the concept of the human interstitium” Benias et al., 2018.
The only thing ‘new’ is the way that this group of scientists observed the tissue that until now has primarily been studied ex vivo. I find it rather humorous to note that it is mainstream news that histologists in the 21st century just realized that there is a difference in the architecture of living versus dead tissue. They noted a significant change in the appearance of tissue slides that were chemically fixed in the traditional manner when compared to studies of in vivo structures as well as fresh frozen samples. The researchers noted this tissue in the dermis as well as urinary system, gastrointestinal system and respiratory system. This further supports one of my favorite talking points presented in the visceral mobilization courses “fascia is fascia is fascia is fascia.”
As an instructor that presents entire courses around the importance of the fascial system within all structures of the body including the dermis, epimysium, all organs, and the adventitia of vessels, I am thrilled to see this layer of the fascial system receive recognition and garner the attention it deserves. However, to refer to the interstitium as a new undiscovered organ is to ignore the work of the International Fascia Research Congress as well as many other notable scientists. These researchers see the fascial system as the dynamic mesenchymal tissue that unites every cell in the body and allows for fluid and tissue movement.
French hand surgeon Dr. Jean-Claude Guimrberteau has documented this tissue utilizing microendoscopy on living subjects for the past 20 years. Dr Guimberteau created a brilliant DVD called Strolling Under the Skin, you can view an excerpt available on YouTube. Following the success of several videos, he went on to co-author the book Architecture of Human Living Fascia: The extracellular matrix and cells revealed through endoscopy.
Another brilliant researcher is Orthopedic Surgeon Dr. Carla Stecco. Her paper The Fascia: the forgotten structure is an excellent review of the three-dimensional continuity of the myofascia. Following multiple publications, she also authored the book The Functional Atlas of the Human Fascial System. Her work is limited to the myofascial layer and does not include the visceral fascia although she notes its presence in her published works. For those that would like to know more about this tissue, I highly recommend both of these authors. If you wish to explore how a physical therapist can utilize this information in clinical practice, join me for one of my courses on fascial manipulation. The fascial based treatment for pelvic dysfunction series includes:
Benias, P. C., Wells, R. G., Sackey-Aboagye, B., Klavan, H., Reidy, J., Buonocore, D., ... & Theise, N. D. (2018). Structure and Distribution of an Unrecognized Interstitium in Human Tissues. Scientific Reports, 8(1), 4947. https://:doi.org/10.1038/s41598-018-23062-6, 2018.
Stecco, C., Macchi, V., Porzionato, A., Duparc, F., & De Caro, R. (2011). The fascia: the forgotten structure. Italian journal of anatomy and embryology, 116(3), 127.