Life Wellbeing The newfound ‘organ’ you never knew you had

The newfound ‘organ’ you never knew you had

The interstitium, scientists found, is under our skin and between our organs. Photo: Getty
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A group of scientists have discovered a new organ in the human body.

In a new study published in the journal Scientific Reports, researchers have detailed the structure and distribution of spaces in the human body that they say represent a newfound organ – and it could be the biggest organ in the body.

It has been called interstitium, named after the widespread, fluid-filled spaces within and between tissues all over the body, the study states.

The previously unrecognised feature of the human anatomy is found just below the skin’s surface, surrounding arteries and veins, casing the fibrous tissue between muscles, and lining our digestive tracts, lungs, and urinary systems.

It has been reported as the body’s natural “shock absorber”, protecting the body’s organs and muscles with its interconnected compartments.

Scientists say the organ has seemingly been hidden in plain sight as a result of how tissue is studied. For decades it did not show up on standard microscopic slides used by researchers.

To find these pockets of interstitial fluid, medical researchers looked at living tissue instead of sampling dead tissue samples, with a probing technique called confocal laser endomicroscopy.

Interstitium new organ
An image of the interstitium beneath the top layer of skin. Photo: Mount Sinai Health System/Jill Gregory

Previously, researched thought the layer was simply dense connective tissue, but the new finding reveals that this tissue is more like an “open, fluid-filled highway”.

“Now, it’s clear that by looking in the living tissue at the microscopic level with this new confocal laser endomicroscopy … that space is fully expanded and filled with fluid,” New York professor of pathology and study co-author Dr Neil Theise said.

“Once you see it, you can’t unsee it.”

He said that about 60 percent of the human body is made of water, and about two-thirds of that is found in cells. The remaining third is only partially known.

The new study also suggests that interstitium may help scientists better understand how cancer spreads, Mr Theise said.

“These anatomic structures may be important in cancer metastasis, edema, fibrosis and mechanical functioning of many or all tissues and organs,” he said.

“It’s been known that when cancer invades this layer, either in the skin or in the viscera, that’s when it first becomes able to spread outside the organ of where it arose.”

If the research is widely accepted the interstitium could be regarded as the body’s 80th organ.