Scientists discover a new human organ hiding in plain sight

Thursday, 29 Mar, 2018

"What we saw in this layer of the bile duct is this open fluid filled space supported by this collagen bundle latticework", Theise, who now works at New York University School of Medicine told Reuters on Tuesday.

They realised traditional methods for examining body tissues had missed the interstitium because the "fixing" method for assembling medical microscope slides involves draining away fluid - therefore destroying the organ's structure. Scientists prepare tissue this examination by treating it with chemicals, slicing it thinly, and dying it to highlight key features.

Just when you thought we knew everything there was to know about the human body, scientists go and discover a new organ.

According to the team co-led by New York University's (NYU) School of Medicine, Interstitium which is supported by a mesh of strong and flexible connective tissue protein can be regarded as the 80th and the largest organ in the human body.

"I think what the paper shows is the benefit of having new ways to image and look at tissues". But this process causes the fluid-filled cavities to collapse.

Theise and his colleages are now researching whether analysis of the newly discovered channels may allow doctors to identify invasive cancer in its earliest stages.

For decades they appeared on slides but were dismissed as a layer of connective tissue.

This fluid is rich in protein that drains into the lymphatic system, the network of vessels carrying lymph, a fluid that contains disease-fighting white blood cells.

The human body holds 60 percent water. Researchers have known about the "interstitium" - the tissue between organs and vessels in the body - for a long time.

According to reports, the interstitium protects the body's organs, muscles and other tissues from "bumps and shocks".

Using a newer technology called probe-based confocal laser encomicroscopy, the researchers were able to view living tissues instead of fixed ones.

"These were the remnants of the collapsed spaces", study author and pathologist Dr Neil Theise said.

The organ's true objective was finally discovered during a routine endoscopy looking at a patient's bile duct.

For this study the team looked at the interstitium using a powerful microscope using confocal laser endomicroscopy wherein the tissue samples are bathed in a fluorescent liquid to delineate their structure in minute details. He adds that the concept of a fluid-filled matrix is not "earth-shattering", and that sectioning and imaging unfixed tissue as the authors did, which could tear and create artifacts, presents limitations. They suggest that these spaces could be compressed or stretched, and therefore act as "shock absorbers" in the body. "The more tissues I saw, the more I realized it's everywhere", he said. As per the study, the layers of the body so far considered dense, connective tissues are actually interconnected compartments that are filled with fluids.

Theise noted that there may be quite a bit of information already known about this fluid-filled space; it's just that researchers "didn't know what they were looking at".

The findings were published on March 27 in the journal Scientific Reports.