Scientists may have discovered why gene-edited pig kidneys are rejected in humans

Chinese scientists transplanted a pig lung into a human being—but it had to be removed

In August 2025, Chinese scientists transplanted a pig lung into a brain-dead person, a common research step for this type of experimental work. Researchers used CRISPR technology to alter six proteins in the pig genes to make the organ seem less foreign to the human immune system. Within a day there were indications the organ wasn’t functioning well and that the person’s body was rejecting it. Scientists ended the experiment after nine days.

One man lived with a gene-edited pig kidney for 271 days, a record

In October 2025, Tim Andrews had his gene-edited pig kidney removed because it was no longer working well. He had the transplanted organ for 271 days—surpassing the prior record of a patient who functioned with one for 130 days. Andrews remains on the kidney transplant wait list to receive a donated kidney from a human, but he has a particularly hard-to-match blood type, making it challenging to get the organ.

Read why one man agreed to get a pig kidney in 2025 to replace his own failing organ

The 68-year-old New Hampshire man told USA Today that a motivator for the experimental surgery was his belief that he was going to die anyway, and other people suffering from kidney disease could gain valuable insights. Yet the surgery bought him time—he lived 271 days with a pig organ and later received a human kidney transplant. Clinical trials began in 2026 to test the pig xenotransplants in more people.

A first-of-its-kind clinical trial taps livers from gene-edited pigs to clean blood

The experimental dialysis-like treatment from United Therapeutics, eGenesis, and OrganOx, is designed to help people with liver failure. The therapy, which involves attaching the modified pig liver externally, filters a patient’s blood so their own livers can temporarily rest and perhaps heal.

Xenotransplants are an experimental last resort for the terminally ill

David Bennett Sr., the world’s first genetically modified pig heart transplant recipient, explained his reasoning to his University of Maryland Medical Center care team in 2022 regarding why he accepted a pig organ: He was dying and ineligible for a human heart transplant so this was a last-ditch effort, he said. He died two months after receiving the heart.

After the patient died, a latent pig virus was discovered inside his xenotransplant

Researchers studying the death of David Bennett Sr., the first gene-edited pig heart transplant patient, discovered potential factors that may have contributed to his demise. One finding is that there was a latent virus, called porcine cytomegalovirus (PCMV), in the pig heart, which may have contributed to dysfunction of the transplant.

See different pig-to-human xenotransplantation possibilities

Xenotransplantation can include the insertion of any organ, tissue, cells or fluids from any nonhuman animal into a human. This US Food and Drug Administration graphic about pig-to-human applications shows different possibilities, including the exploration of using pig pancreatic cells for treating diabetes.

US federal researchers are blocked from putting certain human cells in animals

In 2015, US policymakers put a halt to any government-funded work that would insert human stem cells into animals. The reasoning was that human cells might spread through the animal's body and perhaps to its brain, blurring the line between humans and nonhumans. The ban remains in place today even as gene-edited pig parts are being placed in humans.

Pig brain cellular activity was restarted hours after death in study published in 2019

Yale University scientists restored basic cellular activity and circulatory function in pig brains about four hours after death with a synthetic cocktail of preservatives and nutrients. This work— which didn't restart electricity activity in the brain or consciousness—could help advance future human stroke and brain injury treatments.

Transplanted organs can be rejected by the body immediately, months after transplant, or slowly over years

Organ rejection remains a huge challenge for organ transplant recipients. Rejection occurs when a recipient's immune system identifies a transplanted organ as foreign and attacks it. Recipient-donor screening processes try to match antigens to help reduce this risk.

Pig organ transplants are apparently kosher—you just can’t eat them

Science writer Mary Roach speaks with journalist Terry Gross about her latest book, “Replaceable You: Adventures in Human Anatomy” and discusses topics including why pig organs have become of such interest and what religious leaders have told her about pig organs and compliance with Jewish dietary law.

Mice were able to regenerate retinal cells in the lab—a breakthrough for mammals

Using gene therapy, a team of Korean researchers has enabled retinal regeneration in mice by blocking the intercellular transfer of a single inhibitory protein. This 2025 finding creates a new potential direction for treating retinal diseases. The work, which is still in animal studies, is projected to enter early-stage clinical trials in the next few years.

A clinical trial is underway in 2026 to help kidney transplant recipients avoid a lifetime of immunosuppressing drugs

This later-stage clinical trial, in Chicago and Taiwan, evaluates the efficacy and safety of a new cellular therapy that may be swapped in for immunosuppressing drugs among kidney transplant recipients. The study randomizes people to either receive standard immunosuppressants or this cellular therapy and fewer immunosuppressants. It only includes kidney transplant recipients receiving organs from live donors so transplant surgery timing won't hinge on the unpredictable schedule of performing surgery and follow-up care when a donor dies.

How personalized gene-editing saved a baby's life

KJ Muldoon had a 50% chance of surviving a genetic mutation until doctors developed a one-of-a-kind gene-editing therapy. In an interview with one of the researchers behind the treatment, learn what it will take to make personalized genetic medicine possible for everyone.

Thousands of donated human kidneys are thrown away annually

Ten donated kidneys are thrown away daily even though thousands of people are awaiting a kidney transplant. Listen to a kidney doctor and a 2012 economics Nobel laureate discuss why this happens and how the organ transplantation system may be improved. Transplant centers are penalized for low transplant survival rates, they note, and that contributes to why hospitals may decide certain organs are just too risky to use.

Artificial intelligence may improve organ donation systems—and even organ health

Mayo Clinic transplant experts suggest that artificial intelligence could potentially improve organ donation systems in several ways, including better identifying patients most at risk for organ rejection, enhancing donor-recipient matching, and helping to avoid organ transplant needs by identifying health issues earlier.

Move over gene editing, scientists can edit your epigenome

Instead of deleting genes, epigenetic editing modulates their activity. A new paper tests if it’s able to undo a genetic effect of early alcohol exposure.

As of 2025, perfect synthetic replication of natural organs remains elusive

Advancements such as 3D printing muscles, performing vaginal reconstruction with colon tissue, and growing organs in a lab have shown promise, but artificial options and transplanting substitutions continue to exhibit functional and performance limitations compared to their natural equivalents.

Biotech is trying to boost drug production efficiency—using chicken eggs

A company called Neion Bio is genetically engineering birds in a bid to produce medical compounds, a herculean task that scientists have struggled with for decades. The US FDA has approved only one chicken-derived drug in the past—an expensive treatment for a rare liver disorder. (Some users may encounter a paywall.)

Genetic drug matching, called pharmacogenomics, can help avoid dangerous drug reactions

Certain gene variants can affect how quickly or slowly medications are broken down in the body, affecting drug effectiveness and the risk of drugs failing. Such testing is often not covered by insurance companies though research indicates if these tests were performed for more than six drugs across the US population, avoided ailments would likely climb into the hundreds of thousands. (Some users may encounter a paywall.)

Research advances suggest death takes much longer than we realized

Recent research indicates that organs, including the brain, are better at handling a lack of oxygen after the heart stops beating than previously known. Such findings may open up possibilities that include someday reversing certain death processes and expanding the availability of organs available for organ donations. (Some users may experience a paywall.)

Neural replays in mice help explain food aversions

Princeton University scientists published research in 2025 analyzing how mice learn to associate certain foods or flavors with feeling ill—even when there’s a time gap between eating something and feeling sick. The work, performed with grape Kool-Aid and injections of a substance that made mice sick, traced the literal “gut reaction” of how gut distress signals are linked to neural replays of what the mouse ate.

Two festival-goers were hospitalized after receiving peptide injections, raising questions

Investigative journalism shop ProPublica wrote about two people who became extremely ill following antiaging peptide injections. Authorities were examining whether the individuals were sickened by an infection, contamination related to the injections, or an issue with the medication itself, according to documents obtained by the journalists at ProPublica.

Genetic blood test offers an estimated clock on when Alzheimer's symptoms may appear

The 2026 research finding from researchers at Washington University School of Medicine in St. Louis—if validated in broader populations—suggests that an already available blood test could estimate when Alzheimer's symptoms may begin within a margin of several years. The test detects a protein called p-tau217 found in blood plasma and the researchers incorporated the findings from that blood test into a statistical model to come up with the symptom timeline predictions.

Indefinite cloning of some endangered species may not sustain their longevity because cloning success rates decrease as genetic mutations accumulate.

How Nobel Prize-winning research unraveled why the immune system doesn't always attack itself

The 2025 Nobel Prize was awarded to scientists who discovered how immune system soldiers are typically stopped from attacking healthy tissue. The work furthered autoimmune understanding and cancer therapies.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

Read a deep dive on the 'all-purpose healing' peptide BPC-157.

Larger animals like giraffes, elephants, and blue whales have developed a unique defense against cancer, a phenomenon known as Peto's Paradox

Experimental hantavirus vaccines and therapies, still under development, have long been funded by the US military.

Learn how monoclonal antibodies, which mimic the body's antibodies, can fight diseases like Ebola.

Recent research found that the brain doesn't seem to massively rewire following amputation—upending earlier beliefs about the cause of phantom limb pain.

Hookworm infection, though risky, may help fight certain autoimmune conditions by tamping down the immune system's inflammatory response.

Tattoos remain visible on your skin thanks to immune cells called macrophages

Against his wishes, Albert Einstein's brain was removed before his cremation, and the pathologist responsible stored it for decades in mason jars within a beer cooler.

At the beginning of the 20th century, a group of young men ate standard American food—replete with food additives like borax and formaldehyde—as part of government research to better understand food safety.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Watch how algorithms can be designed to train themselves and self-improve without human input, to the point where the optimized code is too complex for programmers to understand.

Planarian flatworms are small, aquatic worms with exceptional regenerative capabilities. When cut, the worms can regenerate multiple bodies in a matter of weeks.

Famed poet TS Eliot rejected the manuscript for George Orwell's political fable 'Animal Farm,' writing that its criticism of authoritarianism was not 'the right point of view.'

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Poison ivy was sent to Europe in the 1600s as an exotic, ornamental oddity, where it was purposefully grown in the English royal gardens at Kew, the Faculty of Medicine in Paris, and a few other locations.

Studies suggest when you sleep is as important as how much you get, and syncing with your circadian rhythms may lead to less fatigue and improved long-term health outcomes

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

A researcher recently discovered an interview from 1967 between groundbreaking journalist Joan Didion and the Grateful Dead, years before the band became an institution.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

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The distributor behind 'Rocky Horror' pulled the film from its scheduled national release, believing it would be a failure, though it eventually amassed a dedicated fanbase through midnight showings, a trend that continues over 50 years later.