Tag Archives: kidney

Scientists transplant pig kidney into a human – Again

Credit: Pixabay.

Just two months after they successfully grafted a pig kidney to a human, researchers at NYU Langone Health have performed a second surgery. In both instances, all went according to plan, which suggests that perhaps not too far into the future, animal-to-human transplants, or xenotransplantation, could become the norm, solving our organ donation crisis that kills thousands each year on the waiting lists.

“We have been able to replicate the results from the first transformative procedure to demonstrate the continued promise that these genetically engineered organs could be a renewable source of organs to the many people around the world awaiting a life-saving gift,” says Dr. Robert Montgomery, Professor of Surgery and chair of the Department of Surgery at NYU Grossman School of Medicine. “There is much more work to do before we begin living human trials, but our preliminary findings give us hope.”

During the first transplant, the kidney of a genetically modified pig was attached via a large blood vessel to a brain-dead patient from outside the body. Out of all mammals, a pig’s organs are the most compatible with those of humans in terms of size and metabolism, which explains why scientists chose this animal. 

However, the pig from which the kidney was sourced still required genetic modification because the animals produce a sugar molecule called alpha-gal that humans do not. Biocompatibility can make or break a transplant and issues can appear even between organs sourced from humans, not to mention those belonging to an entirely different species. The pigs used in this transplant were bred by biotech firm Revivicor and lacked the alpha-gal gene.

In this recent, second procedure, the kidney was transplanted into a functionally dead organ donor whose vital functions were kept operational using a ventilator. The kidney was attached externally through a blood vessel in the upper leg. This was rather out of practical reasons. The kidney could have been placed internally in its normal position just as well.

The pig kidney was covered in a protective shield and kept under observation for the 54 hours the life-support machines were running. It functioned as expected with urine production and creatine at normal levels, equivalent to what you’d expect to see in a human kidney transplant. There were no signs of organ rejection throughout the procedure and observation period.

“We continue to make progress with the single-gene knockout xenotransplantation,” says Dr. Montgomery. “With additional study and replication, this could be the path forward to saving many thousands of lives each year.”

Clinical trials with live patients are probably a long time into the future as scientists still have to jump through many regulatory and safety hoops before they can attempt crossing such a truly revolutionary milestone. But the efforts are worth it. More than 90,000 people are on a kidney transplant waiting list in the United States alone, and many die before they get their turn. 

Study links coronavirus with acute kidney injury in NYC

Trying to better understand the impact of the coronavirus, researchers are taking a closer look at its effects on those who have been diagnosed with the virus.

Credit Wikipedia Commons

In New York, a hospital study showed coronavirus is causing damage to patients’ organs, with the kidneys being particularly affected. Knowing the proportion of patients at risk for such damage could help hospitals as they plan for future coronavirus surges.

A team at Northwell Health, the largest health provider in New York state, found that over a third of the patients treated for COVID-19 developed acute kidney injury and nearly 15% required dialysis.

“We found in the first 5,449 patients admitted, 36.6% developed acute kidney injury,” study co-author Dr. Kenar Jhaveri, associated chief of nephrology at Hofstra/Northwell in Great Neck, New York, told Reuters.

The study is the largest so far to look at kidney injury in COVID-19 patients. It may be helpful, Jhaveri said, as other hospitals face new waves of patients with the disease, which has infected more than 4.3 million people and killed over 295,000.

Acute kidney injury (AKI) causes a rapid decline in kidney function, which can lead to long-term damage and even death. The condition causes a build-up of waste products in the blood and makes it difficult for the kidneys to keep the right balance of fluids.

Risk factors for developing the condition include age, diabetes, heart disease, and hypertension. Older males and black patients with COVID-19 were at high-risk for kidney failure, the study found.

The researchers analyzed electronic health records of 5,449 hospitalized coronavirus patients between March 1 and April 5, finding that 36.6% ( 1,993) of these patients developed AKI. By the study’s conclusion, 39% of AKI patients were still hospitalized.

“Working amidst the COVID-19 epicenter was an experience we will never forget. Nephrologists and the dialysis staff were on the front lines of this battle trying to help every patient we could,” Jhaveri said. “We hope to learn more about the COVID-19 related AKI in the coming weeks

Among the more than 1,000 patients who needed to be placed on a ventilator, about 90% developed acute kidney failure. Only 21.7% of the 925 patients who developed the condition did not need mechanical breathing assistance. Very ill patients often develop kidney failure, Jhaveri said.

The team is currently involved in several other studies on patients with COVID-19. They recently found that nearly all coronavirus patients had at least one underlying medical condition that put them at risk of contracting the killer bug.

The study was published in the journal Kidney International.

Coronavirus damages the lungs in severe cases, as well as the heart and kidneys

 This image shows a CT scan from a man with COVID-19. Pneumonia caused by the new severe acute respiratory coronavirus 2 can show up as distinctive hazy patches on the outer edges of the lungs, indicated by arrows. 

The new coronavirus causes COVID-19, a respiratory disease that in the most severe cases attacks the lungs, destroying cells and potentially triggering death. Every day we learn new things about the coronavirus, and most of them aren’t pretty. The latest reports suggest that it’s not just the lungs that are attacked, other organs like the kidneys and heart are also severely affected, with potentially life-threatening consequences.

When the virus infects lung cells, it starts replicating. But our immune system doesn’t just wait by idly. It knows that the body is under attack by a foreign invader and, in response, it starts mobilizing the troops — a swarm of antibodies. However, these immune cells don’t just kill infected cells, they can also attack healthy cells, triggering inflammation.

As a result, air sacs in the lungs become swollen and filled with fluid — essentially the patient now has pneumonia and experiences breathing difficulties.

These symptoms also make it challenging for the lungs to pump oxygen in the blood, which can trigger a cascade of problems. Less oxygen naturally triggers more inflammation. All types of tissue, especially organs, require oxygen to function properly. So, with limited oxygen supply, other organs start to fail.

According to Alan Kliger, a nephrologist at Yale School of Medicine, about half of the COVID-19 patients who were hospitalized had blood or protein in their urine, which is a telltale sign of kidney damage.

Speaking to the Washington Post, Kliger added that preliminary data shows that 14% to 30% of intensive-care patients in New York and Wuhan, China, lost kidney function and required dialysis. In China, autopsies on deceased COVID-19 patients found that nine out of 26 had acute kidney injuries.

“That’s a huge number of people who have this problem. That’s new to me,” Kliger said. “I think it’s very possible that the virus attaches to the kidney cells and attacks them.”

There’s also evidence that the virus also attacks the heart. Physicians in both New York and China have reported a similar incidence of myocarditis and irregular heart rhythms that can lead to cardiac arrest in COVID-19 patients. According to a review of ICU cases from China, 40% of patients suffered arrhythmias and 20% had some form of cardiac injury.

Although much rarer, there are reports of liver damage due to COVID-19. There’s one such case in Long Island and five in China, but the small sample size is not enough to draw definite conclusions.

What’s particularly worrisome is the danger of blood clots in the veins of legs and other blood vessels. A study published last week monitored 81 patients with COVID-19 pneumonia in a Wuhan hospital, finding that 20 patients had blood clots that traveled to the lungs. lungs. Blood clots in the lungs are particularly dangerous because they can potentially trigger a fatal pulmonary embolism. Eight of the patients died as a result.

In New York, doctors are already treating ICU patients with blood thinners to counter the viral-triggered blood clots.

This kind of damage might be due to a cytokine storm — the overreaction of the body’s immune system that can cause complications and multiple organ failure. Cytokines are small proteins released by many different cells in the body, including those of the immune system where they coordinate the body’s response against infection and trigger inflammation.

Researchers hope to get to the bottom of things by investigating other possible causes of organ and tissue damage. Other causes include respiratory distress, medication, high fever, and the stress of intensive care unit hospitalization.

Kidneystone.

Kidney stones form like any rock, may hold day-by-day history of your body’s health

Kidney stones are actual stones, in the geologic sense of the word, new research reveals.

Kidneystone.

Fluorescence micrograph of a human kidney stone.
Image credits Mayandi Sivaguru et al., 2018, Nature.

The combined efforts of an interdisciplinary team — which included a geologist, a microscopist, and a medical doctor — revealed a surprising trait of kidney stones. These lumps of matter, traditionally believed to be homogenous elements, actually form layer-by-layer, just like any other natural or artificial mineralization.

More crucially, however, the team reports that kidney stones partially dissolve and regrow throughout their lifetime — a discovery that may unlock new, noninvasive treatments for these hurtful pebbles.

Kidney stones don’t break your bones

Kidney stones are built up from calcium-rich layers that bear a striking resemblance to other mineralizations in nature, such as those forming coral reefs, Roman aqueducts, stalactites or stalagmites, structures associated with hot springs, or subsurface oil fields, the team reports. This goes directly against the common-held wisdom that kidney stones are unique among all other rocks in nature, being homogenous and never dissolving.

“Contrary to what doctors learn in their medical training, we found that kidney stones undergo a dynamic process of growing and dissolving, growing and dissolving,” explains University of Illinois geology and microbiology professor Bruce Fouke, co-lead researcher of the paper.

“This means that one day we may be able to intervene to fully dissolve the stones right in the patient’s kidney, something most doctors today would say is impossible.”

The team’s findings were made possible by new imaging technology. This allowed the authors to look at the stones in better detail than ever before, and also employ a wider array of light- and electron-based microscopy for the task. To give you an idea of how extensive the microscopy effort was as part of this research, the methods applied by the team included: bright-field, phase-contrast, polarization, confocal, fluorescence and electron microscopy, several combinations of these methods, topped off with X-ray spectroscopy.

What’s really exciting to me personally, given my background in geophysics, is that many of these imaging techniques are traditionally the domain of geology and other earth sciences. While common-place in such fields, they haven’t really been used to study mineralizations in living organisms, such as kidney- or gallstones, Fouke remarks.

The team’s use of ultraviolet light during imaging was also particularly helpful, he adds, as the technique makes certain minerals or proteins fluoresce at the right wavelengths — allowing for quick and accurate identification of these elements under the microscope. A relatively new technology, Airyscan super-resolution microscopy, also allowed the team to snap some incredible, 140-nanometer resolution shots of the kidney stones’ structures:

Kidney stones microscopy.

COD= calcium oxalate dihydrate; COM= calcium oxalate monohydrate; UA= uric acid; HSE= historic sequence of events.
Image credits Mayandi Sivaguru et al., 2018, Nature.

“Instead of being worthless crystalline lumps, kidney stones are a minute-by-minute record of the health and functioning of a person’s kidney,” Fouke explains.

The images reveal that kidney stones start out as tiny crystals of calcium oxalate dihydrate, a mineral known as Weddellite. These crystals may lose some water, depending on conditions in the body, transitioning into calcium oxalate monohydrate (mineral Whewellite). And yes, they do sound a bit like Pokemon names.

In the early phases of kidney stone formation, these crystals bind together into irregular clumps. Organic matter and other mineral species later cake onto this core in successive layers, creating an outer shell. The process is very well known to geologists.

The presence of these layers also allowed the team to recreate the developmental history of the kidney stone, just like you would with a geological structure. Gaps in these layers point to certain parts of the stones — usually the interior dihydrate crystals — having dissolved in the past, the team reports. These gaps were subsequently filled, usually by calcium oxalate monohydrate crystals.

Kidney stone formation.

Image credits Mayandi Sivaguru et al., 2018, Nature.

“In geology, when you see layers, that means that something older is underneath something younger,” Fouke said. “One layer may be deposited over the course of very short to very long periods of time.”

“Therefore, just one rock represents a whole series of events over time that are critical to deciphering the history of kidney stone disease,” Fouke said.

The research shows that, far from being a single lump of stable crystal, kidney stones are actually a hodge-podge of whatever minerals and organic substances happened to trail along the kidney during the stone’s lifetime. They are also very dynamic, evolving continuously, potentially encasing a history of the body’s going-ons over time.

“Given these rough estimates, each nano-layer may have formed on a sub-daily basis of hours or in some cases even minutes,” the paper reads.

“If correct, kidney stones could be ‘read’ in the future under clinical conditions as an unprecedented ultrahigh-sensitivity record of in vivo human renal function and dynamic biogeochemical reactions.”

The paper “Geobiology reveals how human kidney stones dissolve in vivo” has been published in the journal Nature.

Encapsulate

To HEK with diabetes: new cell capsule could treat the condition with 0 insulin shots

A new cell-based treatment for type 1 and 2 diabetes could eliminate the need for constant insulin injections for patients. The method showed its effectiveness in mice trials, and the team hopes to test in on human patients within two years.

Insulin Syringe

Image credits Melissa Wiesse.

The method uses a capsule of genetically engineered cells which is grafted under the patient’s skin. They monitor blood glucose levels and automatically secret and release insulin when needed. This would lead to more reliable and more efficient treatment to the condition than the ones we use now — where patients administer their own insulin. But we’re still a way off from that. The ETG University team behind the new capsule hopes they will obtain a human clinical trial license for the technology in the next two years, with potential commercialization in the next decade.

A growing issue

In 2013, some 24.4 million American adults were estimated to suffer from one form or another of diabetes, and as a rough estimate 10% of them had type 1. This condition usually begins developing in childhood as the body’s immune system starts systematically destroying all the pancreatic beta cells. These cells are the body’s sugar’o’meter, and release insulin to regulate glucose levels in the blood. So without them, patients have to get regular insulin shots or face the risk of hyperglicemia. Type 2 diabetes by contrast, is also usually associated with low levels of insulin but is characterized by high resistance to the hormone. Some type 2 patients also require shots of insulin to keep blood levels in check.

But relying on insulin shots is already showing limitations, and the number of diabetes cases is expected to explode worldwide in the next few decades, according to the team. So a more efficient treatment is required.

“By 2040, every tenth human on the planet will suffer from some kind of diabetes, that’s dramatic. We should be able to do a lot better than people measuring their glucose,” said lead researcher Martin Fussenegger.

Fussengger added that if the technology is green-lighted for human use, diabetes patients could trade daily injections for the implant which would need to be replaced three times per year. It would do a much better job than than the shots which do not perfectly control blood glucose levels leading to complications such as eye, nerve, and heart damage associated with diabetes. Should it pass the trials, the capsule could do a lot of good by treating patients of type 1 diabetes as well as those with type 2 that require insulin shots.

Sweetening the deal

Previous efforts have tried to develop methods of artificially growing pancreatic cells from stem cells. Manufacturing these cells en masse has proven difficult, however, and the cells were prone to dying once introduced in the body.

“They are prima donnas in the cellular context,” he said.

Team thus looked at the more resilient kidney cells for a solution. A type known as HEK cells were grafted with two new genes allowing them to take on the role of pancreatic cells. One of them makes the cells sensitive to glucose levels and the other instructs them to release insulin into the blood after glucose levels rise get too high.

They were tested on mice (who were treated so that they lost all insulin-producing cells). The modified HEK cells were then implanted in porous capsules (think of a teabag) that protected the human cells from the mice’s immune response while allowing insulin to flow out.

The approach was found to be better at regulating blood-sugar levels than pancreatic cells and remained healthy three weeks after implantation.

Encapsulate

Even the Daleks are excited at the idea.
Image modified after Radio Times.

“It’s hard to understand why ours should be better than something that evolved for millions of years,” said . “It shows that as engineers, thinking rationally, we can also do a very good job.”

In the study, mice were treated such that they lost all their insulin-producing pancreatic cells. The cells were then implanted into the mice, enclosed in a teabag-like porous capsule that protected the human cells from the mouse immune system, but allowed the hormone to diffuse out. One advantage of this approach is that the cells don’t have to be genetically matched to the patient. Capsules could be produced and frozen on an industrial scale, to be used whenever needed.

The full paper “β-cell–mimetic designer cells provide closed-loop glycemic control” has been published in the journal Science.

Wearable artificial kidney may change how we perform dialysis forever

Wearable artificial kidneys may soon replace traditional dialysis machines, the results of a new clinical study show. While there are still some teething issues to fix before wide scale use, patients praised the system’s portability and ease of use.

The working prototype of the Wearable Artificial Kidney developed by Dr. Victor Gura and his team.
Image credit: Stephen Brashear/University of Washington.

Dialysis is required by patients whose kidneys can no longer effectively clean waste products out of the bloodstream. Current treatments are done in three treatment sessions a week. These are performed in hospitals as the process involves big, stationary machines which filter the patient’s blood. As you can probably imagine this is quite a hassle and overall unpleasant experience for the patients, and having access to a wearable device that would allow treatment to be performed at home or while mobile would be a huge quality of life improvement for them.

The FDA authorized trials of a prototype device that does all this, dubbed the “Wearable Artificial Kidney”. The trials involved seven patients from the University of Washington Medical Center in Seattle during late 2015. The experiments aimed to determine how efficient the new device is at the task, but also whether or not it could be safely used for prolonged periods of time.

The wearable kidney was effective in clearing the patients’ blood of all waste — such as urea, creatine and phosphorus — and clearing excess amounts of water and salt. Even more, while the diets of dialysis patients are heavily restricted (because they need to keep their electrolyte and blood volumes in balance) there are no limitations for patients using the Wearable Artificial Kidney.

Users’ circulatory systems remained stable, and they reported no side effects during the trials. Unfortunately, after the seventh patient the team ran into technical problems with the device, such as a significant formation of carbon dioxide gas bubbles within the dialysis solution and variations in this solution and blood flow rates.

The schematics of the device.
Image credits: Stephen Brashear/University of Washington

These teething issues need to be solved before the gear can become commercially available, but the initial results are very promising. They show that the concept of a wearable dialysis device is viable, and patients reported a much higher satisfaction with it than with conventional treatments in use today — especially because they can perform the treatment at home and because they’re free to continue with their day to day life while doing it.

The redesign of the components will be directed towards ease of use and reliability, but the researchers said their number one priority is for patients to be able to perform the treatment at home — either by themselves or by those taking care of them.

The results of the study have been published online in the Journal of Clinical Investigation under the title “A wearable artificial kidney for patients with end-stage renal disease” and can be read here.

Lab-Grown Kidneys Transplanted to Animals

For the first time, Japanese researchers have successfully grown a pair of kidneys in a lab and then transplanted them into animals. The organs functioned just fine, and this gives big hopes for the transplants ultimately moving to humans.

Dr. Takashi Yokoo and one of the test subjects. Image via CBS.

So far, they tried it on rats and pigs; the rats ones worked well right from the start, but it was more of a challenge moving on to a more advanced animal like a pig (pigs are actually similar to us biologically in a number of ways). The positive results that they reported on pigs actually raises hopes for human transplants.

Professor Chris Mason, an independent scientist based at University College London praised the study.

“This is an interesting step forward. The science looks strong and they have good data in animals.”

The artificial kidneys were created from embryonic stem cells, grown in the lab. Dr Takashi Yokoo and colleagues at the Jikei University School of Medicine in Tokyo also set a drainage tube and a bladder for the kidneys, to prevent them from swelling up and accumulating liquids. Urine first passes from the artificial kidney to the artificial bladder and then to the real bladder. Eight weeks later, when they checked their results, everything was still working fine.

However, while extremely promising, human trials are still years away. Mason added:

“This is an interesting step forward. The science looks strong and they have good data in animals. But that’s not to say this will work in humans. We are still years off that. It’s very much mechanistic. It moves us closer to understanding how the plumbing might work. At least with kidneys, we can dialyse patients for a while so there would be time to grow kidneys if that becomes possible.”

Journal Reference: Shinya Yokote et al, Urine excretion strategy for stem cell-generated embryonic kidneys. doi: 10.1073/pnas.1507803112

Mouse embryonic kidney cells (seen here in red) were used to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Kidney 3-d structures from human stem cells made for the first time

Scientists at the   Salk Institute for Biological Studies have for the first time coaxed   human stem cells into forming three-dimensional cellular structures similar to those found in our kidneys. The breakthrough could provide a valuable footing for upcoming work that might eventually lead to fully functioning lab-grown kidneys, based on patients’ own cells for bio-compatibility. In its current stage, lab-grown kidney-like structures such as the one developed by Salk researchers can be effectively used today as test beds for various kind of drugs.

In the U.S. alone some 4.4 million people are suffering from some form of kidney disease. Unlike other vital organs, the kidney rarely recover function once its damaged by disease; typically a transplant is required, and while treatment can alleviate symptoms and make life manageable, patients still need to make the plunge to surgery. Transplants are far too few for the current demand – growing bio-compatible kidneys would be a solution, and as you might imagine it’s an extremely challenging task.

Mouse embryonic kidney cells (seen here in red) were used  to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Mouse embryonic kidney cells (seen here in red) were used to coax the human stem cells to grow into the nascent mushroom-shaped buds (blue and green). (c) Salk Institute for Biological Studies

Previous methods have had limited success, however the present attempt successfully morphs  human stem cells into well-organized 3D structures of the ureteric bud (UB), which later develops into the collecting duct system.  Ureteric bud cells  are responsible for reabsorbing water after toxins have been filtered out and during embryonic development in the womb, later develop into a conduit for urine drainage from the kidney.  This was achieved using both human embryonic stem cells and induced pluripotent stem cells (iPSCs) – adult cells, like those harvested from the skin for instance, that are manipulated to behave like natural stem cells and thus later differentiate into any kind of cell.

[RELATED] First bio-engineered kidney works after transplant in rats 

First the researchers stimulated the stem cells or iPSCs to developed into mesoderm, a germ cell layer from which the kidneys develop using growth factors – cells that signal and offer cues to stem cells to differentiate into desired types of cells. In this instance, the researchers used mouse cells as growth factors.

The team tested their method by developing three-dimensional structures of the kidney via iPSCs harvested from  a patient clinically diagnosed with polycystic kidney disease (PKD) , a genetic disorder which can lead to kidney failure. So far, neither  gene- nor antibody-based therapies have proven to treat PKD, however using  their methodology it may be possible for pharmaceutical companies and other investigators studying drug-based therapeutics for PKD and other kidney diseases.

“Our differentiation strategies represent the cornerstone of disease modeling and drug discovery studies,” says lead study author Ignacio Sancho-Martinez, a research associate in Izpisua Belmonte’s laboratory. “Our observations will help guide future studies on the precise cellular implications that PKD might play in the context of kidney development. ”

Findings appeared in the journal Nature Cell Biology.

A kidney in a bioreactor after seeding with cells. After transplantation it filtered blood and produced urine. Photograph: Ott Lab/Center for Regenerative Medicine

First bio-engineered kidney works after transplant in rats

A kidney in a bioreactor after seeding with cells. After transplantation it filtered blood and produced urine. Photograph: Ott Lab/Center for Regenerative Medicine

A kidney in a bioreactor after seeding with cells. After transplantation it filtered blood and produced urine. Photograph: Ott Lab/Center for Regenerative Medicine

In a milestone of modern medicine, medical researchers at the Harvard Medical School and Massachusetts General Hospital in Boston have produced the first bioengineered kidney and then successfully transplanted it in a host rat, where it become functional. Each year millions of people die of liver related diseases, and even those who go through the living hell of climbing up the waiting list and get a transplant don’t generally fair too well after the operation because of incompatibilities. Mass produced, bioengineered organs made from the patient’s own cells could save countless lives and the present research shows that we’re making huge strides towards achieving this monumental goal, albeit many more steps need to be taken.

Surgeon Harald Ott Harvard Medical School and Massachusetts General Hospital in Boston along with colleagues  first collected cherry-sized kidneys from dead rats and then employed an ingenious method relying on a detergent solution to strip away the cells. After this operation was finished, what remained were the scaffolds of material the cells were normally embedded in that maintained the original architecture of the organs – a strategy which was previously shown to work for other organs as well, like hearts and lungs.

When bioengineering is concerned, one of the biggest challenges scientists face is growing the consisting cells such that they may work together to form an organ. Armed with this simple method, the basic structure they require is easily at hand now. Next, they carefully filled the scaffold with kidney and blood vessel cells from the recipient rats, and then placed the compound into a bioreactor where liquids filled with nutrients and other essential compounds fed the cells for them grow into a kidney within 12 days.

These bioengineered kidneys were then implanted in rats that had one of their kidneys removed, and since the implants kept the complex architecture of their scaffolds this meant they could be connected to the recipients’ blood and urinary systems. Amazingly, the transplanted kidneys performed their waste filtering functions, producing urine and showing no evidence of bleeding or clot formation. The only problem, one the researchers hope to solve or at least improve on, is that the transplanted kidneys are only 5 to 10 percent as efficient as healthy kidneys.

The researchers claim that this is because the cells they used were still immature, and with a bit of work they hope they can get to 20% which is still far away from healthy kidney functions, but still helpful to a lot of people. There are currently millions of people around the world who rely on blood dialysis machines to help them survive, machines that only provide 10 percent to 15 percent of the functioning of healthy kidneys, and come with an enormous hassle, making living a normal life extremely difficult.

Of course, we’re still talking about bioengineered rat kidneys. The human liver is roughly 100 times bigger and more complex, but the researchers are confident they can scale their work. So far, they have shown the cell-removal technique they applied on rat kidneys also works on pig and human kidneys, so they only need to find a way to refine their process to grow human liver cells on the scaffolds.

“We’ve shown an initial proof of concept that has some promise,” Ott says. “Now it’s time to start the nitty-gritty work, to solve all the technical problems.”

Not long ago, scientists used stem cells to grow the first human kidneys using such a procedure, and recently great strides are made in the attempt to 3-d print fully functional organs. No matter the method, we can only hope scientists come to a functioning transplant.

Findings were reported in the journal Nature Medicine.