Researchers have reported the discovery of a previously unknown part of the human anatomy.
The newly identified network of fluid-filled channels in the human body could be a previously unknown organ.
In a study published in Scientific Reports on March 27, Neil Theise, from the Department of Pathology at NYU Langone Health, and colleagues reported of fluid-filled spaces in the connective tissues of the body that include those below the surface of the skin, those lining the lungs, digestive tract and urinary systems, and surrounding arteries, muscles, and veins.
These tissue layers were once thought as a dense wall of collagen, a strong structural protein in the connective tissues. The new study revealed that the supposed wall is actually more like an open and fluid-filled highway and these interconnected fluid-filled spaces are supported by collagen.
The researchers called this network of fluid-filled spaces the interstitium. They think that each tissue of the human body may be surrounded by a network of these channels, which in essence forms an organ. They also estimate that this organ contains about a fifth of the total volume of fluid of the human body.
The fluid-filled spaces have been missed for a long time because they do not show in the standard microscopic slides. Tissue samples placed on these slides are often treated with chemicals, cut into thin slices, and dyed to highlight their key features. All these processes drain away the fluid and cause the newly identified fluid-filled spaces to collapse.
"This fixation artifact of collapse has made a fluid-filled tissue type throughout the body appear solid in biopsy slides for decades, and our results correct for this to expand the anatomy of most tissues," Theise said.
May Offer Explanation On How Cancer Spreads
Researchers said that the interstitium may shed light on how cancer spreads and their findings could potentially drive dramatic advances in the field of medicine.
"These anatomic structures may be important in cancer metastasis, edema, fibrosis, and mechanical functioning of many or all tissues and organs," the researchers wrote in their study.
"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."
The interstitium is already called an organ but this is an unofficial distinction. The researchers said that for this body part to be considered an organ, there should be a consensus around the idea. The presence of these fluid-filled spaces also needs to be confirmed.