Tag Archives: organ

Human mini-livers set the stage for an organ donor free future

Researchers grew a miniature liver from human skin cells, and then they transplanted it into rats. The study could be a small step in developing a revolutionary technology that could help thousands of people who are waiting for a liver transplant.

Credit University of Pittsburgh

This technology could help reduce organ shortage and it could also potentially lower the cost of a transplant. In the US alone, about 17,000 people are waiting for a liver transplant, according to Columbia University – a number that largely exceeds the amount available. At the same time, organ transplants are usually very expensive, especially in the US. In 2017, a patient receiving a liver transplant was billed over $800,000.

This development would also be very significant for the estimated 30 million people in the U.S. who have a liver disorder, according to the Health Resources and Services Administrator. The researchers are indeed optimistic.

“I believe it’s a very important step because we know it can be done,” co-author Alejandro Soto-Gutiérrez, a regenerative medicine researcher at the University of Pittsburgh, told Inverse. “You can make a whole organ that can be functional from one cell of the skin.”

Soto-Gutiérrez and his team of researchers collected skin cell samples from a group of human participants. Then they reprogrammed the skin cells into stem cells. After that, the cells were coaxed into various types of cells found in the human liver.

According to the paper, the scientists removed cells from rat livers so it could serve as a scaffolding for the stem cells they created. The human liver cells were seeded into this scaffolding, and finally, the livers were transplanted into the rats. It took under a month to grow the livers in bioreactors, while liver maturation usually takes up to two years.

Four days after the transplant, the researchers dissected the animals and discovered that the mini-livers had successfully worked. They saw that the rats had human liver proteins in their blood serum, and that with the mini-livers had secreted bile acids and urea just like a normal liver.

“Seeing that little human organ there inside the animal — brown, looking like a liver — that was pretty cool,” Soto-Gutiérrez told Inverse. “This thing that looks like a liver and functions like a liver came from somebody’s skin cells.”

Nevertheless, there were some unwanted side-effects. The researchers found problems with blood flow around the site of the graft (where the liver was transplanted). They argued that the following steps should address safety issues.

Soto-Gutiérrez and his team are working to create technology to enable widespread and access on-demand of human liver grafts that are functional.

“The long-term goal is to create organs that can replace organ donation, but in the near future, I see this as a bridge to transplant,” said Soto-Gutierrez. “For instance, in acute liver failure, you might just need a hepatic boost for a while instead of a whole new liver.”

The study was published in the journal Cell Reports.

Meet your new organ: the interstitium

Doctors have identified a previously unknown feature of human anatomy with many implications for the functions of most organs and tissues, and for the mechanisms of most major diseases.

Structural evaluation of the interstitial space. (A) Transmission electron microscopy shows collagen bundles (asterisks) that are composed of well-organized collagen fibrils. Some collagen bundles have a single flat cell along one side (arrowheads). Scale bar, 1 μm. (B) Higher magnification shows that cells (arrowhead) lack features of endothelium or other types of cells and have no basement membrane. Scale bar, 1 μm. (C) Second harmonics generation imaging shows that the bundles are fibrillar collagen (dark blue). Cyan-colored fibers are from autofluorescence and are likely elastin, as shown by similar autofluorescence in the elastic lamina of a nearby artery (inset) (40×). (D) Elastic van Gieson stain shows elastin fibers (black) running along collagen bundles (pink) (40×).

A new paper published on March 27th in Scientific Reports, shows that layers of the body long thought to be dense, connective tissues — below the skin’s surface, lining the digestive tract, lungs, and urinary systems, and surrounding arteries, veins, and the fascia between muscles — are instead interconnected, fluid-filled spaces.

Scientists named this layer the interstitium — a network of strong (collagen) and flexible (elastin) connective tissue fibers filled with fluids, that acts like a shock absorber to keep tissues from rupturing while organs, muscles, and vessels constantly pump and squeeze throughout the day.

This fluid layer that surrounds most organs may explain why cancer spreads so easily. Scientists think this fluid is the source of lymph, the highway of the immune system.

In addition, cells that reside in the interstitium and collagen bundles they line, change with age and may contribute to the wrinkling of skin, the stiffening of limbs, and the progression of fibrotic, sclerotic and inflammatory diseases.

Scientists have long known that more than half the fluid in the body resides within cells, and about a seventh inside the heart, blood vessels, lymph nodes, and lymph vessels. The remaining fluid is “interstitial,” and the current paper is the first to define the interstitium as an organ in its own right and, the authors write, one of the largest of the body, the authors write.

A team of pathologists from NYU School of Medicine thinks that no one saw these spaces before because of the medical field’s dependence on the examination of fixed tissue on microscope slides. Doctors examine the tissue after treating it with chemicals, slicing it thinly, and dyeing it in various colorations. The “fixing” process allows doctors to observe vivid details of cells and structures but drains away all fluid. The team found that the removal of fluid as slides are made makes the connective protein meshwork surrounding once fluid-filled compartments to collapse and appear denser.

“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,” says co-senior author Neil Theise, MD, professor in the Department of Pathology at NYU Langone Health. “This finding has potential to drive dramatic advances in medicine, including the possibility that the direct sampling of interstitial fluid may become a powerful diagnostic tool.”

Researchers discovered the interstitium by using a novel medical technology — Probe-based confocal laser endomicroscopy. This new technology combines the benefits of endoscopy with the ones of lasers. The laser lights up the tissues, sensors analyze the reflected fluorescent patterns, offering a microscopic real-time view of the living tissues.

When probing a patient’s bile duct for cancer spread, endoscopists and study co-authors Dr. David Carr-Locke and Dr. Petros Benias observed something peculiar — a series of interconnected spaces in the submucosa level that was never described in the medical literature.

Baffled by their findings, they asked Dr. Neil Theise, professor in the Department of Pathology at NYU Langone Health and co-author of the paper for help in resolving the mystery. When Theise made biopsy slides out of the same tissue, the reticular pattern found by endomicroscopy vanished. The pathology team would later discover that the spaces seen in biopsy slides, traditionally dismissed as tears in the tissue, were instead the remnants of collapsed, previously fluid-filled, compartments.

Researchers collected tissues samples of bile ducts from 12 cancer patients during surgery. Before the pancreas and the bile duct were removed, patients underwent confocal microscopy for live tissue imaging. After recognizing this new space in images of bile ducts, the team was able to quickly spot it throughout the body.

Theise believes that the protein bundles seen in the space are likely to generate electrical current as they bend with the movements of organs and muscles, and may play a role in techniques like acupuncture.

Another scientist involved in the study was first author Rebecca Wells of the Perelman School of Medicine at the University of Pennsylvania, who determined that the skeleton in the newfound structure was comprised of collagen and elastin bundles.

Researchers 3D-print shockingly realistic human organ models

The new organs that researchers have 3D printed don’t only look like the real deal, but they also feel like it.

Researchers can attach sensors to the organ models to give surgeons real-time feedback on how much force they can use during surgery without damaging the tissue. Credits: McAlpine Research Group.

3D printing has taken the world by storm, and medicine especially can benefit from the technology. So far, people have 3D printed human cartilage, skin, and even artificial limbs — and we’ve just started to scratch the surface of what 3D printing can do. Now, researchers from the University of Minnesota have developed artificial organ models which look incredibly realistic.

“We are developing next-generation organ models for pre-operative practice. The organ models we are 3D printing are almost a perfect replica in terms of the look and feel of an individual’s organ, using our custom-built 3D printers,” said lead researcher Michael McAlpine, an associate professor of mechanical engineering at the University of Minnesota’s College of Science and Engineering.

The 3D-printed structures not only mimic the aspect of real organs, but also the mechanical properties, look and feel of real organs. They include soft sensors which can be customized depending on the desired organ. The sensors offer real-time feedback on how much force is being applied to them, notifying doctors when they are close to damaging the organ.

The technology could help students get a better feel for real organs and learn how to improve surgical skills. For doctors, it could help them prepare for complex surgeries. It’s a great step forward from previous models of artificial organs, which were generally made from hard, unrealistic plastic.

“We think these organ models could be ‘game-changers’ for helping surgeons better plan and practice for surgery. We hope this will save lives by reducing medical errors during surgery,” McAlpine added.

In the future, researchers want to develop even more complex organs, as well as start incorporating defects or deformities. For instance, they could add a patient-specific inflammation or a tumor to an organ, based on a previous scan, enabling doctors to visualize and prepare for an intervention.

Lastly, this could ultimately pave the way for 3D-printing real, functioning organs. There’s no fundamental reason why we can’t do this, it’s just that we’re not there yet. This invention could be a stepping stone for such advancements.

“If we could replicate the function of these tissues and organs, we might someday even be able to create ‘bionic organs’ for transplants,” McAlpine said. “I call this the ‘Human X’ project. It sounds a bit like science fiction, but if these synthetic organs look, feel, and act like real tissue or organs, we don’t see why we couldn’t 3D print them on demand to replace real organs.”

The research was published today in the journal Advanced Materials Technologies.

pig organ transplant

Pig organ transplants into humans might be two years away in China

Chinese scientists are now desperately seeking government approval to launch a clinical trial for xenotransplantation. The goal is to have genetically modified pig organs transplanted into humans. This could happen as early as 2019.

pig organ transplant

Credit: Pixabay.

Every country on Earth is in short supply of organs for transplants with some patients staying on waiting lists for years, some over a decade. Suffice to say most die from health complications before they get a chance to receive a heart, lung or kidney. This situation could go on forever unless we find a way to literally grow transplant organs.

An unbeaten path

One promising approach involves genetically modifying pigs whose organs can then be transplanted to a human patient. This procedure is referred to as xenotransplantation. Out of all mammals, a pig’s organs are the most compatible with those of humans in terms of size and metabolism.

To demonstrate how such a procedure might work, scientists working with the National Heart, Lung and Blood Institute, USA, grafted a pig’s heart to a baboon’s last year. The researchers suppressed the alpha 1-3 galactosyltransferase gene which produces an epitope that is easily recognized as foreign. This way, the baboon’s immune system doesn’t attack the pig heart although immunosuppressants still had to be taken.  Amazingly, the longest a pig heart kept beating was 945 days or nearly three years.

The leader in this field, however, is China. According to the South China Morning Post, about 1,000 cloned pigs are made inside dedicate clone farms around China.

Also in China, no fewer than ten national institutes are closely collaborating for xenotransplantation project funded by the central government. Already, there is fantastic progress. For instance, 400 cornea transplants have been performed from pigs to humans with a stunning 95 percent success rate once the Chinese government gave the green light in 2015.

Now, the same scientific consortium is looking permission from the government to make the next big step: a clinical trial for organ xenotransplantation.

This could happen as early as two years from now, South China Morning Post reported, although there’s a good chance the deadline could be extended even further. It seems like the Chinese government is delaying giving the go. Corneas, which don’t contain blood vessels, are one thing but an organ which can be mind-wrecking complex is a whole different ballgame.

“We have patients dying from organ failure and their desperate relatives pleading for them to have the chance to live,” said Zhao Zijian, director of the Metabolic Disease Research Centre at Nanjing Medical University in Jiangsu.

“But when we turn to the authorities in charge of approving the clinical trials, all we get is silence. We understand it must be very hard for the government to make a decision, but it’s time we got an answer,” he added.

Zhao admitted, however, that genetically modified pig organs are barely a 50 percent match for human organs. According to the Chinese leading scientist, it’s quite possible that a pig organ transplanted tomorrow inside a human’s body won’t get rejected. The big risk though is in the long term such as inflammation as a result of the immune system attacking the transplanted heart or lung.

Even in such an experimental stage, however, for many patients, such a procedure would be much welcomed. In the end, there can’t be progress absent clinical trials.

“Someone has to take the first step – whether it’s the US Food and Drug Administration or the China Food and Drug Administration,” he said.

Dr. J. Calvin Coffey inspecting a model of the mesmery. Credit: University of Limerick.

Meet the new organ of the human body: the mesentery

Dr. J. Calvin Coffey inspecting a model of the mesmery. Credit: University of Limerick.

Dr. J. Calvin Coffey inspecting a model of the mesentery. Credit: University of Limerick.

Irish doctors argue that the mesentery — a double fold of the peritoneum which lines the abdominal cavity — ought to be classified as an organ. Previously, the mesentery was thought to consist of fragmented and disparate structures which don’t fit the organ classification. Thus, the mesentery is now the 79th organ in the human body.

In its most simplified version, an organ is a self-contained structure which serves a specific function. Doctors have been aware of the mesentery since the 19th century, but until recently no one thought about upgrading its humble role in the body. Researchers from the University Hospital Limerick, however, have proven that the belt of tissue that holds our intestines in place is made up of a single band of tissue. It starts at the pancreas and goes down through the small intestine and colon.

Credit: J Calvin Coffey

Credit: J Calvin Coffey

Since it’s self-contained and serves a specific vital function (holds our guts in place), the Irish researchers say the mesentery deserves to be considered an organ, though it may not be as fabulous as the heart or liver. It is vital, though. Without the mesentery, our intestines would slop about in the belly — a disaster waiting to happen. You couldn’t live without the mesentery, says  J. Calvin Coffey, one of the lead authors of the two studies of the newly classified organ which first started in 2012 and surgeon at the University of Limerick. A recent paper published in The Lancet by the group from Limerick provides an overview of the latest evidence that supports the mesentery’s classification as an organ.

“The anatomic description that had been laid down over 100 years of anatomy was incorrect. This organ is far from fragmented and complex. It is simply one continuous structure,” Professor Coffey explained.

“When we approach it like every other organ…we can categorise abdominal disease in terms of this organ,” Coffey said in a statement for the press, who adds that mesenteric science is its own specific field of medical study in the same way as gastroenterology, neurology and coloproctology.

Intriguingly, there’s no abled international body that gets the final word on what and what not gets classed as an organ. An update to Gray’s Anatomy from 2015, now in its 41st edition, includes the new definition of the mesentery, which is kind of the next best thing to an arbiter. It’s also not clear yet if the mesentery should be classed part of the vascular system, the endocrine system or another system altogether.

Whatever the case, Coffey hopes the hype around the mesentery will make people more interested in learning more about it. Ultimately, he hopes this renewed interest might spark new research that will help us better understand diseases like Crohn’s and irritable bowel syndrome.

Scientists image organs at microscopic scales

In a new study published in Nature, researchers have demonstrated a technique that allows the mapping of organs at microscopic scales; they detail its use and produced images of the microvessels in the brain of a live rat.

Image of the whole brain vasculature at microscopic resolution in the live rat using ultrafast Ultrasound Localization Microscopy: Local density of intravascular microbubbles in the right hemisphere, quantitative estimation of blood flow speed in the left hemisphere. Credit: ESPCI/INSERM/CNRS

Image of the whole brain vasculature at microscopic resolution in the live rat using ultrafast Ultrasound Localization Microscopy: Local density of intravascular microbubbles in the right hemisphere, quantitative estimation of blood flow speed in the left hemisphere.
Credit: ESPCI/INSERM/CNRS

Current techniques of microscopic imaging are not ideal. Just like in geological imaging techniques, there’s a tradeoff between penetration depth, resolution, and time of acquisition. In other words, if you want to see all the way through the human body, you won’t have good enough resolution – or you will but it will take a very long time. Until now, conventional imaging techniques have worked at milimetre and sub-milimetre scale at best, being limited by one of the fundamental laws of physics: features smaller than the wavelength of the radiation used for imaging cannot be resolved. But Mickael Tanter, a professor at the Langevin Institute and his colleagues have come up with a new approach, and report a new super-resolution.

Like a few other recent studies, they used microbubbles, with diameters of 1–3 micrometres, which were injected into the bloodstream of live rats. They then combined deep penetration and super-resolution imaging in a technique they call ‘ultrafast ultrasound localization microscopy’. With this, they obtained ultra fast frame rates (500 / second), and achieved a resolution equal to the rat brain microvasculature – less than 10 micrometers in diameter (0.01 milimetres).

While this is still a work in progress, authors believe it can help doctors make better diagnostics and better understand how some diseases affect the body.

 

Genetically-altered pigs to become humanity’s source for “spare” organs

Among all the species with which we share the animal kingdom, pigs are the ones whose organs are best suited for transplant in human bodies — they are approximately the same size as our organs and have similar structures, making reconnecting blood vessels much easier. Pigs tend to have large litters and reproduce quickly, making them a very large, very accessible source of “spare parts.”

Never too early to start training that liver.
Image via imgur

So far so good, but why aren’t we all running around with an extra pig spleen or a couple of bonus pig kidneys cleaning our blood? Well, there is a itty bitty hurdle when using pig organs — our bodies freak out when we transplant them. Pig organs are coated with specific sugar molecules that trigger an acute rejection response in human bodies — our antibodies attach themselves to these sugar molecules and destroy the newly transplanted pig organ. Hoping to overcome this problem, researchers are working to create pigs that lack the gene that serves as a template for these sugars.

There are two research efforts being poured into this project currently — Randall Prather at the University of Missouri in Columbia created four cloned piglets from which one had one copy of the sugar-producing gene inactivated (each organisms has two copies of each gene, one from the maternal and one from the paternal side.) The piglets were born in September and October, and a description of Prather’s work was published in the journal Science. The other, a team working for PPL Therapeutics PLC of Scotland, the company that played a part in cloning Dolly the sheep, also announced the birth of a litter of five cloned piglets on December 25th, who’ve also had a copy of the gene inactivated.

The next step involves selectively breeding the pigs, to produce animals lacking both copies of the gene. Theoretically, the organs of these modified pigs could be transplanted into humans without the body rejecting the foreign tissue.

The new results are a significant advance over many other attempts at genetic modification in animals because in both of the studies, the scientists were able to modify—in this case, “knock out”—a gene at a specific location. Although genes from other organisms have been inserted into the genomes of sheep, cattle, and pigs, scientists have had little control over where on a chromosome the new gene is incorporated.

“This is the first time a specific genetic modification has been made in the pig,” said Prather.

Prather’s team, made up of fellows of the University of Missouri and colleagues at the Immerge BioTherapeutics Inc. in Charlestown, Massachusetts, worked directly on fetal pig cells, altering their genetic make-up. These cells were used to grow 3,000 embryo clones that were implanted into 28 surrogate sows, with only seven piglets born, three of which died later.

What started five years ago with the cloning of Dolly, the expectation of creating identical, genetically-controlled organs for transplant into humans, only got one step closer to reality with the cloning of these piglets.

But it’s not all roses — one concern that has dampened the prospects of xenotransplantation is the possibility of spreading viruses from one species to another. Porcine endogenous retrovirus (PERV), for example, is part of a pig’s natural genetic makeup and does not cause any disease in the animal. There is no guarantee, however, that PERV would be harmless in humans.

Still, xenotransplantation might soon become a common practice, as there is an enormous demand for organ transplants that human donors alone will never be able to fill.

human-lung-organoid

First 3D mini lungs grow in the lab help end animal testing

human-lung-organoid

Image: University of Michigan Health System

Stem cells were coaxed to grow into 3D dimensional mini lungs, or  organoids, for the first time. These survived for more than 100 days. These pioneering efforts will serve to deepen our understanding of how lungs grow, as well as prove very useful for testing new drugs’ responses to human tissue. Hopefully, once human tissue grown in the lab becomes closer and close to the real deal (cultured hearts, lungs, kidneys etc.), animal testing might become a thing of the past.

Previously, lung tissue was only grown in  flat (2D) cell systems, basically on thin layers of cell cultures. Some 3D structures had also been developed by scientists, but these were made onto scaffolds from donated organs which had their cells removed. Of course, the organoids grown at the University of Michigan Medical School aren’t what you or me know as lungs. Since these were grown in a dish, the cells lack vital components like blood vessels, which facilitate the gas exchange during breathing. Nevertheless, components like large airways known as bronchi and small lung sacs called alveoli were successfully grown. These 3-D structures are the closest we’ve come to a lab grown lung, according to the paper published in eLife.

To make the lung organoids, the team manipulated  signaling pathways that control the formation of organs.

  1. Stem cells were instructed to form a type of tissue called endoderm, found in early embryos and that gives rise to the lung, liver and several other internal organs.
  2. Scientists activated important development pathways that are known to make endoderm form three-dimensional tissue while inhibiting two other key development pathways at the same time.
  3. Acellular human lung matrix was seeded with spheroids and cultured for 40 days. Resulting matrices had abundant proximal airway-like structures (scale bar 10 μM) (credit: Briana R. Dye et al./eLife)

    Acellular human lung matrix was seeded with spheroids and cultured for 40 days. Resulting matrices had abundant proximal airway-like structures (scale bar 10 μM) (credit: Briana R. Dye et al./eLife)

    The endoderm became tissue that resembles the early lung found in embryos.

  4. This early lung-like tissue spontaneously formed three-dimensional spherical structures as it developed.
  5. To make these structures expand and develop into lung tissue, the team exposed the cells to additional proteins that are involved in lung development.
  6. The resulting lung organoids survived in the lab for more than 100 days.

“These mini lungs can mimic the responses of real tissues and will be a good model to study how organs form, change with disease, and how they might respond to new drugs,” says senior study author Jason R. Spence, Ph.D., assistant professor ofinternal medicine and cell and developmental biology at the University of Michigan Medical School.

“We expected different cells types to form, but their organization into structures resembling human airways was a very exciting result,” says lead study author Briana Dye, a graduate student in the U-M Department of Cell and Developmental Biology.

 

 

Bone marrow-on-a-chip could remove bone marrow animal testing

A new “organ on a chip” has been developed by Harvard researchers, reproducing the structure, functions, and cellular make-up of bone marrow, a complex tissue that until now, could only be studied on living animals.

Microscopic view of the engineered bone with an opening exposing the internal trabecular bony network, overlaid with colored images of blood cells and a supportive vascular network that fill the open spaces in the bone marrow-on-a-chip (credit: James Weaver/Harvard’s Wyss Institute)

Bone marrow is one of the more complex and fragile parts of the human body – many drugs and toxic elements affect the bone marrow in ways that are hard to predict, and hard to study. Until now, the only reason to do this was to study it on living animals, something which, needless to say, is costly, unpleasant, and risky. But now, scientists from Harvard’s Wyss Institute for Biologically Inspired Engineering have developed what they call “bone marrow-on-a-chip”, a device which could be used to develop safe and effective strategies to prevent or treat radiation’s lethal effects on bone marrow without resorting to animal testing.

The main focus of such studies is cancer treatment – many such treatments such as radiation therapy or high-dose chemotherapy are hazardous for bone marrow. Animal testing is not really efficient for studying such matters, and it also raises some moral issues.

“Bone marrow is an incredibly complex organ that is responsible for producing all of the blood cell types of our body, and our bone marrow chips are able to recapitulate this complexity in its entirety and maintain it in a functional form in vitro ,” said Don Ingber, M.D., Ph.D., Founding Director of the Wyss Institute, Judah Folkman Professor of Vascular Biology at Harvard Medical School and Boston Children’s Hospital, Professor of Bioengineering at SEAS, and senior author of the paper.


Ingber leads a larger initiative to develop more “organs on a chip” – small microfluidic devices that mimic the physiology of living organs. So far, they’ve developed lung, heart, kidney, and gut chips that reproduce key aspects of organ function, and have more in the works. In order to build them, they combine multiple types of cells from an organ on a microfluidic chip, while steadily supplying nutrients, removing waste, and applying mechanical forces that the organ would naturally encounter in the human body.

The researchers report the development in the May 4, 2014 online issue of Nature Methods.

 

Organ size is determined by a protein

The latest in a long line of studies conducted on the fruit fly showed that organs have the molecular mechanisms to control their proportions, a process in which a protein called p53 plays the crucial role. The study was conducted by researchers at IRB Barcelona headed by ICREA Professor Marco Milán and will be published in December 15 in the journal PLoS Biology.

Establishing how big an organ will be is a process that takes place during the embryonic development, and the process is absolutely crucial for the proper function of all organisms. Any problem that appears in this development at any stage will cause significant damage to the body at the very least, but usually leads to death. Hormones, such as steroidal hormones and insulin can contribute to maintain the necessary equilibrium, but the balance is very delicate.

“What we have demonstrated is that the organs themselves also have the mechanisms to maintain a balance of shapes and to grow in a coordinated fashion,” states Milán.

The p53 protein is a tumour supressor protein; its importance was known to be huge even before this discovery, because it worked as a “master watchman” against cancer, which is why it is often called the guardian angel gene. Basically, it kills out all cells that have been caused irreversible damage and can become cancerous.

The study in case showed that when some specific cells of the wing are subjected to stress, not only is the growth of this part of the organ reduced but also that of the remaining section, which causes adult fruit flies to have smaller but proportional wings.

“These experiments indicate that stressed cells send signals to the remaining tissues in order to reduce their growth in order to allow damaged tissue to repair itself and allow the organ to grow in a coordinated manner,” explains Milán.

Pic via Wikipedia

Woman with no fear intrigues researchers
Courage is not the absence of fear, but being afraid and facing it; for a 44 year old woman who is referred to “SM” for privacy reasons, that is not an option – she can not feel fear, biologically. Researchers have tried and tried with their best techniques to scare her, but there was absolutely no result.

Haunted houses, monsters, snakes and spiders only managed to make her curious or to entertain her; she suffers from a rarecondition called Urbach–Wiethe disease that has destroyed her amygdala, an almond-shaped structure located deep in the brain that plays a crucial role in generating fear responses in numerous mammals, from rats to humans.

This new study revolved around SM and her she was the first ever to confirm that that part of the brain is actually responsible for generating fear responses in humans.