That “New Organ” Everyone Is Freaking Out About Is Probably Not New

Despite the headlines, some experts say the "new organ" — the interstitium — is not new, and not an organ. One said the paper was "old textbook knowledge."

This week, scientists reported the existence of a supposedly new human organ.

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The "organ," called the interstitium, is a network of fluid-filled spaces that lie under the skin and surround organs like the lungs, digestive tract, urinary systems, arteries, veins, and muscles.

In the study, published March 27 in Scientific Reports, Neil Theise, a professor of pathology at NYU, and colleagues described their finding, which came from the analysis of bile duct specimens from 12 patients undergoing gastric surgery.

They expected to find dense connective tissue in the samples, but instead found a "complex network" of collagen bundles, which were lined with cells. They theorized that these structures, which they called an "unrecognized interstitium," were likely to play a key role in cancer metastasis, the process by which tumor cells spread.

The finding has the "potential to drive dramatic advances in medicine," Theise said in a statement.

The findings were covered by a lot of people with headlines like "Newly-Discovered Human Organ May Help Explain How Cancer Spreads," "Newfound 'Organ' Could Be the Biggest in Your Body," and "The Interstitium, the Largest Organ We Never Knew We Had."

Some people even called it a "shocking discovery." The researchers said they were able to see the "highway of moving fluid" (as it's described in the press release) because they used a newer technique called confocal laser endomicroscopy. In previous techniques, they said, the tissue was treated with chemicals and compressed, so it obscured the structures.

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But some experts said this new organ is actually old news.

"The interstitial tissue is a part of every organ, just as blood vessels and lymphatic vessels are part of every organ," said Melody Swartz, a professor at the Institute for Molecular Engineering and the Ben May Department for Cancer Research at the University of Chicago. "They have long been recognized to be fluid-filled and that fluid can move within the interstitial space."

In fact, there are hundreds of studies about these spaces, and their connection to lymphatic vessels, Swartz told BuzzFeed News. She said that researchers study the interstitium in live animals and people using fluorescent tracers and other means. In other words: Its existence is well-known.

She also said the interstitium can't be considered an organ on its own because the tissue is found in all organs and there's no evidence that they are connected. For example, the interstitium of the mesentery, the fold of tissue that attaches your gut to your abdominal wall, is not connected to the interstitium of the skin, she said.

"I strongly feel that this paper has been grossly misrepresented both by the authors and the press," she said.

Helge Wiig, a professor of physiology at the University of Bergen in Norway, who has studied and published continuously on the interstitium for decades, said in an email that "much of what is presented in the actual paper as novel is old textbook knowledge and should not create a buzz."

Researchers have been studying the interstitium for literally decades.

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Timothy Padera, an associate professor in radiation oncology at Harvard Medical School, said he was hesitant to draw even more attention to the study, but that "decades of published data describing" the interstitial space should be used to correct the record.

Matthew R. Glucksberg, a professor of biomedical engineering at Northwestern University, said he did research on interstitial mechanics back in the 1990s. "This publication would have been baffling back then, let alone now," he said in an email. "We know a lot about the interstitium and know it is not an organ."

"An apt analogy might be a research team that buys an expensive telescope, looks at a point between Mars and Jupiter, sees the asteroid belt, and then announce that they have discovered a planet that no one has ever seen before," he said. "We know a lot about the asteroid belt and know that it is not a planet."

But the researchers stand by their discovery.

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"I have no qualms about what we are saying," Theise told BuzzFeed News.

“As far as we have been able to find, and we have scoured the interstitium literature, no one has ever shown a picture of this tissue, with this structure, with these cell types, with this distribution,” he said.

Theise did say this is his first study on the interstitium. "I was not interested in the interstitium," he said. "I had to learn about it in order to figure out what we were seeing here."

His study, which was peer-reviewed, also doesn't mention a "new organ," although Theise said that they are "following up."

The research was based in part on a previous study by Michael H. Nathanson, director of the Yale Liver Center. His team saw the structures but wasn't sure what they were.

Although the new research adds to the understanding of the interstitium, Nathanson said he wouldn't classify it as a new organ. "In my opinion it’s adding a new level of understanding to a region that’s in each type of organ, rather than defining a completely new organ."

So, you know, science. It's a process.


With pretty much every discovery, scientists debate stuff for a while. They argue at meetings and pick apart data. And before everyone agrees it's a "thing," it usually has to be confirmed by multiple research teams. So stay tuned.



A BuzzFeed News investigation, in partnership with the International Consortium of Investigative Journalists, based on thousands of documents the government didn't want you to see.