Scientists Have Discovered a New Organ in the Human Body. What is the Interstitium?

It’s not a second stomach or a mini-brain. But scientists have discovered an important new organ that may play a critical role in how many tissues and other organs do their jobs, as well as in some diseases like cancer.

In a study published in Scientific Reports, a New York University-led team of researchers describe the interstitium, which is a series of connected, fluid-filled spaces found under skin as well as throughout the gut, lungs, blood vessels and muscles.

The bubble wrap-like network only became visible when the pathologists used a new laser endoscope, called a confocal laser endomicroscope, that allowed them to see microscopic tissues in living people. Most studies of tissues missed the interstitium because they rely on biopsies of tissues that are then dried and fixed onto microscope slides; the desiccated samples never showed the fluid-filled spaces.

But when the endoscopic laser was used to remove the pancreas and bile duct in a dozen patients with cancer, the odd spaces became obvious.

In the study, the authors speculate that the spaces could be important for a number of functions, including generating the collagen that supports cells in certain tissues, as well as housing the stem cells that rush in to repair damaged tissues. They may also play a role in conducting electrical signals as cells move and stretch. Because the spaces form a fluid-highway linking tissues and organs, it may also explain why some cancers, if they invade the spaces, spread more quickly than others.