Scientists May Have Just Discovered a New Organ—And It Could Be the Biggest Yet

iStock
iStock

A new study published in Scientific Reports boldly proclaims that researchers from NYU School of Medicine and Mount Sinai Beth Israel Medical Center, both in New York City, have identified a new organ in the body, thought to be the biggest organ of them all. Called "the interstitium," what has long been thought to be merely tough, dense connective tissue running throughout the body—beneath the skin, the visceral organs, around arteries and veins, and in the fascia tissue between muscles—is really a network of fluid-filled compartments whose structure easily defies viewing by traditional methods, the researchers say.

When asked how researchers can call something found in numerous parts of the body an organ, Neil Theise, co-author of the study, and professor of pathology at NYU School of Medicine, tells Mental Floss that it satisfied both definitions of an organ, being "a tissue that is unitary in structure" that has "a unitary set of functions." It might more accurately be called "an organ system" similar to the cardiovascular system and the lymphatic system.

In all of the places that it's found, the interstitium's fluid-filled compartments (which are the source of lymph, a fluid central to immune cell function) are surrounded by bundles of collagen and elastin—strong and flexible connective tissues that seem to form a sturdy framework for the compartments.

They have the "same cell types, same sort of structure [and] architecture, and the same relationship with the lymphatic system wherever they're found," Theise says. This makes sense, because the compartments drain directly into the lymphatic system. This might explain why cancer cells that get into the lymph nodes spread so rapidly.

This connection to the lymphatic system is also interesting because the last time scientists discovered a new part of the body, it too was connected to the lymphatic system: a system of vessels called the "central nervous system lymphatic vessels," which drain lymphatic fluid from the brain to the surrounding lymph nodes.

They believe the interstitium compartments act as a shock absorber that protects organs from tearing as they squeeze and pump during their daily functions. Moreover, since collagen bundles in lab settings are shown to generate electrical current, they suspect the same thing is happening within the compartments as organs and muscles bend and move. Theise thinks this might account for some of the responses people have to alternative medical treatments like acupuncture and myofascial release, which involves applying sustained pressure to myofascial connective tissue to relieve pain.

WHY THE INTERSTITIUM REMAINED HIDDEN FOR SO LONG

Prior to this study, Theise says, the literature describing this interstitial space—often called "the third space" after the cardiovascular and lymphatic systems—has been vague. Part of the problem is that the structure of the interstitium can't be viewed when it's flat—and that's generally how it's been seen. When scientists prepare tissue to put onto slides for viewing under a microscope, they use chemicals to remove the fluids from it, and slice it thinly, causing the normally fluid-filled interstitial compartments to collapse.

Researchers had noticed "cracks" between collagen fibers in fixed slides, but, Theise says, they were always told these were just "artifacts of having torn the tissue."

However, in the fall of 2015, researchers from Mount Sinai Beth Israel Medical Center discovered the true shape of the interstitium by accident when testing out a new technology called probe-based confocal laser endomicroscopy, which offers a microscopic view of living tissue. In this procedure, a thin, camera-bearing probe called an endoscope is snaked down a patient's throat, where scientists can view the insides of organs with a laser that lights the tissues, and a sensor that analyzes the reflected light. There, while scoping a patient's bile ducts, the researchers, who are co-authors on the current paper, saw something they'd never seen before: the interconnected, fluid-filled compartments.

The discovery opens numerous avenues for research. Theise's team will most immediately use the research to look at a rare liver disease they now think may begin inside the interstitial compartments. Next, they'll be gathering all the bits and pieces of information they have on the interstitium for a comprehensive literature review, Theise says, "organ by organ, cell by cell, and disease by disease."

Why Is Pee Yellow?

Chloe Effron
Chloe Effron

WHY? is our attempt to answer all the questions every little kid asks. Do you have a question? Send it to why@mentalfloss.com.

Your body is kind of like a house. You bring things into your body by eating, drinking, and breathing. But just like the things we bring home to real houses, we don’t need every part of what we take in. So there are leftovers, or garbage. And if you let garbage sit around in your house or your body for too long, it gets gross and can make you sick. Your body takes out the garbage by peeing and pooping. These two things are part of your body’s excretory system (ECKS-krih-tore-eee SISS-tem), which is just a fancy way of saying “trash removal.” If your body is healthy, when you look in the toilet you should see brown poop and yellow pee.

Clear, light yellow pee is a sign that your excretory system and the rest of your body are working right. If your pee, or urine (YER-inn), is not see-through, that might mean you are sick. Dark yellow urine usually means that you aren’t drinking enough water. On the other hand, really pale or colorless pee can mean you might be drinking too much water! 

Your blood is filtered through two small organs called kidneys (KID-knees). Remember the garbage we talked about earlier? The chemicals called toxins (TOCK-sins) are like garbage in your blood. Your kidneys act like a net, catching the toxins and other leftovers and turning them into pee.

One part of your blood is called hemoglobin (HEE-moh-gloh-bin). This is what makes your blood red. Hemoglobin goes through a lot of changes as it passes through your body. When it reaches your kidneys, it turns yellow thanks to a chemical called urobilin (yer-ah-BY-lin). Urobilin is kind of like food coloring. The more water you add, the lighter it will be. That's why, if you see dark yellow pee in the toilet, it's time to ask your mom or dad for a cup of water. 

To learn more about pee, check out this article from Kids Health. 

12 Facts About Kidney Stones

Illustration by Mental Floss. Images: iStock
Illustration by Mental Floss. Images: iStock

Kidney stones are more common than ever. According to Harvard Medical School, every year more than 3 million people see a doctor for relief from these hard mineral and salt deposits, which form in your kidney when urine becomes too concentrated. Here's what we know about the condition formally called nephrolithiasis.

1. KIDNEY STONES TYPICALLY CAUSE REALLY PAINFUL SYMPTOMS.

At first you may notice your urine is cloudy, bloody, and foul smelling. Your back may begin to ache, and nausea may come over you. Then, as the stone moves from your kidney into your urinary tract or bladder, sometimes becoming trapped, there’s often an intense, stabbing pain that many people say they wouldn’t wish on their worst enemy.

2. MOST PEOPLE DEVELOP ONE TYPE OF STONE …

What kind of kidney stone you get depends on your diet, fluid intake, genetics, hereditary disorders, and even whether you take certain medications, but the vast majority of people get calcium oxalate stones. They're formed from a mix of calcium in urine and the compound oxalate, which is found naturally in food like nuts, chocolate, and some vegetables, including beets and spinach; oxalate is also produced by your liver. There's some evidence that people who take the seizure medicine topiramate can develop these stones in the form of calcium phosphate.

3. … BUT THERE ARE THREE OTHER KINDS TOO.

Struvite stones are fast-growing mineral deposits that typically develop in response to a urinary tract infection, and can grow large enough to block the kidney, ureter, or bladder before you notice any symptoms; they affect women more than men. Uric acid stones turn up in people who eat a lot of red meat, shellfish, and organ meats, which contain hefty doses of an organic compound called purine that can lead to more uric acid than the kidneys can excrete. Cystine stones are caused by a rare hereditary disorder called cistinuria in which your kidneys excrete excessive amounts of the amino acid cystine.

4. THEY'RE EXTREMELY COMMON—ESPECIALLY IN MEN.

There's a solid chance you could end up with a kidney stone. The National Kidney Foundation notes that one in 10 people will develop one during the course of their life. And if you’re male, take note: Your gender alone is considered a kidney stone risk factor. Men are twice as likely as women to develop them. Another factor is age: Although stones are most common from ages 20 through 50, they tend to peak around age 30.

5. IF YOU’VE HAD A KIDNEY STONE, YOU’LL PROBABLY DEVELOP ANOTHER ONE …

Sorry to say, but simply having a kidney stone puts you at risk for a recurrence. If you’ve had one, the U.S. National Library of Medicine notes that there’s a 30 to 50 percent chance more stones will form within five years.

6. … BUT YOU CAN TAKE STEPS TO PREVENT THEM.

Cutting back on sodium (i.e. deli meats, packaged soups, and processed foods) can help, because a stone can form from excessive salt consumption. You should also avoid too much animal protein—it produces urine containing more acid, which is known to increase your risk for kidney stones—and increase your intake of fruits, vegetables, whole grains, and low-fat dairy. And be sure to drink plenty of fluids, especially water—at least 12 glasses a day. (That's good advice for everyone, not just those prone to kidney stones.)

Don't drink much apple or cranberry juice as both contain oxalates and are linked to an increased risk of developing calcium oxalate stones. High doses of Vitamin C may boost the concentration of oxalate in urine; the Cleveland Clinic recommends a daily maximum of 500 milligrams.

7. IT'S A MYTH THAT CALCIUM CREATES SOME KIDNEY STONES.

Despite the fact that the word calcium is part of the most common kind of kidney stone, you don’t need to treat calcium as the enemy. In fact, having too little calcium can actually increase the odds you’ll get these types of stones. According to the Cleveland Clinic, eating about two or three servings of calcium-rich foods daily reduces oxalate absorption, helping to keep calcium oxalate stones away. So get out the cheese.

8. IF YOU PASS A STONE, CONGRATULATIONS! NOW TAKE IT TO A DOCTOR.

Ninety percent of kidney stones are passed through urination. Getting one out this way may hurt a lot, but once the stone has finished causing you agony, it could provide clues that could help you avoid developing another one. If you’re able to retrieve the stone, bring it to your doctor, who can order an analysis. Identifying its components can reveal the kind of stone it is and potentially point to a treatment or prevention plan.

9. IF YOU CAN’T PASS A STONE, TREATMENTS ARE AVAILABLE …

In an attempt to exit the body, a stone travels from the kidney to the bladder through a narrow tube called the ureter. If the stone is larger than a quarter-inch, it's simply too big to pass through the ureter, and will get trapped there. (If it can make it through to your bladder, it's small enough to pass out out of your body through the urethra.) This causes intense pain, blocked urine flow, and possible bleeding from urinary tract walls. That's when it's time for treatment.

There are several methods for getting rid of a kidney stone, all of which aim to break the stone into smaller pieces so they can leave the body. In an extracorporeal shock wave lithotripsy (from the Greek for "crushed stone"), high-frequency sound waves are applied externally to break stones up, allowing them to pass when you pee. Laser lithotripsy takes a similar approach: Stones in the ureter are broken up with a laser and also leave the body naturally. More invasive is percutaneous ultrasonic lithotripsy, which involves passing narrow instruments (including a fiberoptic camera) through your back to your kidney; ultrasound breaks the stones up, and then fragments are removed by an instrument. Finally, a ureteroscopy is a treatment option in which a small scope is inserted in the ureter towards the bladder to determine the stone's location. Then it's broken up for natural passage or removed altogether. Luckily, you're unconscious under general anesthesia during the last procedure.

10. … AND THEY'RE FAR SUPERIOR TO THOSE USED IN THE PAST.

Kidney stones are nothing new—mentions of the painful formations go back more than 5000 years, to Mesopotamian medical texts—and medical interventions have occurred for just as long. Stones made it into the Hippocratic Oath, in which physicians swore they would "not use the knife, not even on sufferers from stone," leaving the procedure to "such men as are engaged in this work" [PDF]. Surgeons in ancient Greece and India were attempting stone removal as far back as the 7th century BCE.

The 16th to 18th centuries were a heyday for stone surgeons, who were largely self-taught. The most notorious of them was Frere Jacques Beaulieu. He pioneered the lateral perineal lithotomy—which involved making an incision in the perineum, inserting a terrifying cutting instrument into the bladder, cutting up the stone, and then extracting the pieces with the instrument or his fingers—in the late 17th century. Unfortunately for his patients, he had no technical training, and his method was often deadly; in 1698, after 25 of his 60 patients died, he was banned from doing the procedure—but he didn't stop. He's thought to have performed more than 5000 lithotomies. (And no, the song doesn't seem to be about him.)

11. IF ALL ELSE FAILS, TRY RIDING A ROLLER COASTER.

If you’re a thrill seeker who happens to have kidney stones (and some vacation time), you may be in luck. After a "notable number" of patients reported that riding the Big Thunder Mountain roller coaster at Walt Disney World in Orlando helped them to pass their kidney stones, Michigan State University urologist David Wartinger decided to investigate. He created a kidney replica—complete with kidney stones—put it in a backpack, and let it ride the roller coaster 60 times. It worked—but passing the stones depended on where the backpack was placed in the coaster. Rides in the last car were the most effective, with the stones passing 64 percent of the time, while the front few cars yielded only a 16 percent success rate.

Big Thunder Mountain was the only ride in the theme park that was effective. Neither Space Mountain nor Aerosmith's Rock 'n' Roller Coaster did the trick, likely because they were too fast, with a G-force that pinned the stones in place. Of course, while this is an interesting finding, if you suspect you have kidney stones, speak to your doctor before you high-tail it to Walt Disney World.

12. A KIDNEY STONE THE SIZE OF A MOUSE WAS REMOVED FROM A MAN IN 2004.

The stone measured 5.11 inches at its widest point—a world record. Five years later, a whopping 2.5-pound stone was surgically removed from a man in Hungary in 2009. Perhaps seeing a bunch of kidney stones in one place other than originating from your own body will put you at ease. If that’s the case, check out the International Museum of Surgical Science in Chicago, where a collection of stones is on display in glass jars.

SECTIONS

arrow
LIVE SMARTER