A view of the interstitium at low-magnification; a network of fluid-filled chambers.
Source: Wikimedia Commons
By Sam Neff
A recent study conducted at the NYU School of Medicine has defined a new organ in the human body (1). It is called the interstitium, and scientists have known of this body region previously as a matrix of flowing fluid enmeshed in collagen and elastin fibers (2). But in light of a better understanding of interstitial function, NYU scientists feel that it should be labelled an organ (a collection of tissues that perform some essential task for the body) (1).
The study offers a new definition of the interstitium as a shock absorber which prevents the repetitive contractions of muscles and blood vessels from damaging surrounding tissues. The fluid within the chambers is not static, but constantly in motion; draining its contents into lymphatic vessels (which help eliminate toxic molecules from the body). The structural proteins, collagen and elastin, help to support the interstitial network (1,3).
The interstitial space has been insufficiently studied in the past because traditional microscopy techniques involve viewing dead, stained tissue and entail the draining of fluid from the specimen of interest. As a result, the chambered structure of the interstitium collapses (1). In this study, however, bile-duct tissue was imaged within the body during cancer surgery. This approach preserved the interstitum’s structure and allowed for a more accurate anatomical picture to emerge (3).
With this new-found knowledge of interstitial anatomy, scientists may now acquire a better understanding of certain diseases. One area of potential progress lies in the treatment of interstitial lung disease, which characterized by scarring and inflammation of the tissues surrounding the lungs (4). In vivo (within the body) microscopy experiments that examine and compare the interstitium of healthy and diseased patients may provide useful insights into disease pathology. Scientists could see exactly what kinds of structural defects contribute to interstitial disease and develop therapy to treat them or prevent further breakdown.
The recent discovery also sheds light on the way that cancer is able to metastasize (spread) so quickly. The mobile fluid of the interstitium allows cancer cells to migrate (1). Perhaps new cancer treatment approaches will target the newfound organ; erecting barriers to interstitial fluid flow in an attempt to halt cancer cell movement. However, more knowledge of the interstitium and its essential functions is necessary to engineer a treatment that does not cause more problems than it solves.
References
(1) NYU Langone Health / NYU School of Medicine. (2018, March 27). “Newfound ‘organ’
had been missed by standard method for visualizing anatomy.” ScienceDaily. ScienceDaily.
Retrieved 30 March 2018 from
<www.sciencedaily.com/releases/2018/03/180327093954.htm>
(2) J. Scallan, V.H. Huxley, R.J. Korthuis. (2010). Capillary Fluid Exchange: Regulations,
Functions, and Pathology. Chapter 2: “The Interstitium.” National Center for Biotechnology
Information. National Center for Biotechnology Information. Retrieved 3 April 2018 from
<https://www.ncbi.nlm.nih.gov/books/NBK53446/>
(3) Petros C. Benias, Rebecca G. Wells, Bridget Sackey-Aboagye, Heather Klavan, Jason
Reidy, Darren Buonocore, Markus Miranda, Susan Kornacki, Michael Wayne, David L. Carr-
Locke, Neil D. Theise. (2018, March 27). “Structure and Distribution of an Uncrecognized
Interstitium in Human Tissues. Scientific Reports 8: Article number 4947, Nature. Retrieved
30 March 2018 from < https://www.nature.com/articles/s41598-018-23062-6>
(4) “Interstitial Lung Disease” American Thoracic Society. American Thoracic Society.
Retrieved 30 March 2018 from < https://www.thoracic.org/patients/patient-
resources/breathing-in-america/resources/chapter-10-interstitial-lung-disease.pdf>