Tag: kidney transplant

World’s First Gene-edited Pig Kidney Transplant into Living Recipient

Surgeons prepare the pig kidney for transplantation. Credit: Massachusetts General Hospital

Massachusetts General Hospital (MGH) has announced the world’s first successful transplant of a genetically-edited pig porcine) kidney into a 62-year-old man living with end-stage kidney disease (ESKD). Surgeons from the Mass General Transplant Center conducted the four-hour-long surgery on Saturday, March 16. The procedure marks a major milestone in the quest to provide more readily available organs to patients. Mass General Brigham is an internationally recognised leader in transplantation services, providing advanced care for a wide spectrum of organ and tissue transplants throughout its renowned academic medical system.

Under the leadership of Leonardo V. Riella, MD, PhD, Medical Director for Kidney Transplantation, Tatsuo Kawai, MD, PhD, Director of the Legorreta Center for Clinical Transplant Tolerance, along with Nahel Elias, MD, Interim Chief of Transplant Surgery and Surgical Director for Kidney Transplantation, a genetically-edited pig kidney with 69 genomic edits was successfully transplanted into a living patient.

Mass General Brigham has a rich history in organ transplant innovation, including the world’s first successful human organ transplant (kidney) performed at Brigham and Women’s Hospital in 1954 and the nation’s first penile transplant, performed at MGH in 2016. Mass General Brigham transplantation programs draw upon the deep, integrated expertise of some of the world’s leading transplant physicians and scientists who collaborate across experienced multidisciplinary teams to advance medicine and improve the lives of patients.

“Mass General Brigham researchers and clinicians are constantly pushing the boundaries of science to transform medicine and solve significant health issues facing our patients in their daily lives,” said Anne Klibanski, MD, President and CEO, Mass General Brigham. “Nearly seven decades after the first successful kidney transplant, our clinicians have once again demonstrated our commitment to provide innovative treatments and help ease the burden of disease for our patients and others around the world.”

“The tireless commitment of our clinicians, researchers and scientists to improving the lives of our transplant patients – both current and future – is at the very heart and soul of academic medicine and what it means to work and provide care at Mass General Brigham,” said David F. M. Brown, MD, President, Academic Medical Centers, Mass General Brigham. “We are so thankful to the incredible staff throughout our hospitals who helped make this surgery a success, and to the patient for his bravery and courage.”

“The success of this transplant is the culmination of efforts by thousands of scientists and physicians over several decades. We are privileged to have played a significant role in this milestone. Our hope is that this transplant approach will offer a lifeline to millions of patients worldwide who are suffering from kidney failure,” Kawai said.

The pig kidney was provided by eGenesis, from a pig donor that was genetically-edited using CRISPR-Cas9 technology to remove harmful pig genes and add certain human genes to improve its compatibility with humans. Additionally, scientists inactivated porcine endogenous retroviruses in the pig donor to eliminate any risk of infection in humans. Over the past five years, MGH and eGenesis have conducted extensive collaborative research, with the findings published in Nature in 2023.

This successful procedure in a living recipient is a historic milestone in the emerging field of xenotransplantation – the transplantation of organs or tissues from one species to another – as a potential solution to the worldwide organ shortage. According to the United Network for Organ Sharing (UNOS), more than 100 000 people in the U.S. await an organ for transplant and 17 people die each day waiting for an organ. A kidney is the most common organ needed for transplant, and end-stage kidney disease rates are estimated to increase 29-68% in the U.S. by 2030, according to literature published in the Journal of the American Society of Nephrology.

The patient, Mr. Richard ‘Rick’ Slayman of Weymouth, Mass., is recovering well at MGH and is expected to be discharged soon.

“The real hero today is the patient, Mr Slayman, as the success of this pioneering surgery, once deemed unimaginable, would not have been possible without his courage and willingness to embark on a journey into uncharted medical territory. As the global medical community celebrates this monumental achievement, Mr Slayman becomes a beacon of hope for countless individuals suffering from end-stage renal disease and opens a new frontier in organ transplantation,” said Joren C. Madsen, MD, DPhil, Director of the MGH Transplant Center.

Mr Slayman said in a statement, “I have been a Mass General Transplant Center patient for 11 years and have the highest level of trust in the doctors, nurses, and clinical staff who have cared for me. When my transplanted kidney began failing in 2023, I again trusted my care team at MGH to meet my goals of not just improving my quality of life but extending it. My nephrologist, Dr Winfred Williams, MD and the Transplant Center team suggested a pig kidney transplant, carefully explaining the pros and cons of this procedure. I saw it not only as a way to help me, but a way to provide hope for the thousands of people who need a transplant to survive. I want to thank everyone at MGH who has cared for me, especially Dr Williams, Dr Kawai, the surgeon who performed my first kidney transplant and now this one, and Dr Riella, who has orchestrated the logistics behind this new transplant. They have supported me during every step of the journey, and I have faith they will continue to do so.”

Mr Slayman, who has been living with Type 2 diabetes and hypertension for many years, previously received a kidney transplant from a human deceased donor in December 2018, performed at MGH by Kawai, after being on dialysis seven years prior. The transplanted kidney showed signs of failure approximately five years later and Mr Slayman resumed dialysis in May 2023. Since resuming dialysis, he encountered recurrent dialysis vascular access complications requiring visits to the hospital every two weeks for de-clotting and surgical revisions, significantly impacting his quality of life and a common problem among dialysis patients.

“The continued success of this groundbreaking kidney transplant represents a true milestone in the field of transplantation. It also represents a potential breakthrough in solving one of the more intractable problems in our field, that being unequal access for ethnic minority patients to the opportunity for kidney transplants due to the extreme donor organ shortage and other system-based barriers. This health disparity has been the target of many national policy initiatives for over 30 years, with only limited success. An abundant supply of organs resulting from this technological advance may go far to finally achieve health equity and offer the best solution to kidney failure – a well-functioning kidney – to all patients in need. I commend Mr Slayman, who has been my patient for many years, for his courageousness in becoming a trailblazer in the field of transplantation,” Williams said.

The procedure was performed under a single FDA Expanded Access Protocol (EAP) – known as compassionate use – granted to a single patient or group of patients with serious, life-threatening illnesses or conditions to gain access to experimental treatments or trials when no comparable treatment options or therapies exist. Mr. Slayman also received infusion of novel immunosuppressant drugs, tegoprubart, provided by Eledon Pharmaceuticals, Inc., and ravulizumab, provided by Alexion Pharmaceuticals, Inc.

Source: Massachusetts General Hospital

Implanted Bioreactors Functioning as Artificial Kidneys Could One Day Replace Dialysis

Photo by Robina Weermeijer on Unsplash

Scientists at UC San Francisco are working on a new approach to treating kidney failure that could one day free people from needing dialysis or a transplant and the associated immunosuppressive drugs.

The technology, described in Nature Communications, shows for the first time that kidney cells, housed in an implantable device called a bioreactor, can survive inside the body of a pig and mimic several important kidney functions. The device can work quietly in the background, like a pacemaker, and does not trigger the recipient’s immune system to go on the attack.

Eventually, scientists plan to fill the bioreactor with different kidney cells that perform vital functions like balancing the body’s fluids and releasing hormones to regulate blood pressure, then pair it with a device that filters waste from the blood.

The aim is to produce a human-scale device to improve on dialysis, which keeps people alive after their kidneys fail but is a poor substitute for having a real working organ. In the US, more than 500 000 require dialysis several times a week. Many seek kidney transplants, but there are not enough donors, and only about 20 000 people receive them each year. An implantable kidney would be a boon.

This is a key step forward is for The Kidney Project, which is jointly headed by UCSF’s Shuvo Roy, PhD (technical director) and Vanderbilt University Medical Center’s William H. Fissell, MD (medical director).

“We are focused on safely replicating the key functions of a kidney,” said Roy, a bioengineering professor in the UCSF School of Pharmacy. “The bioartificial kidney will make treatment for kidney disease more effective and also much more tolerable and comfortable.”

Inspired by nature, honed by science

Roy and his colleagues engineered the bioreactor to connect directly to blood vessels and veins, allowing the passage of nutrients and oxygen, much like a transplanted kidney would. Silicon membranes keep the kidney cells inside the bioreactor safe from attack by the recipient’s immune cells.

The team used a proximal tubule cell, which regulates water, as a test case. Co-author H. David Humes, MD, from the University of Michigan, had previously used these cells to help dialysis patients in the intensive care unit with life-saving results.

No immunosuppression needed

The team tracked the renal cells and the recipient animals for seven days after transplantation and both did well. The next step will be month-long trials, as required for by the U.S. Food and Drug Administration (FDA), first in animals and eventually in humans.

“We needed to prove that a functional bioreactor will not require immunosuppressant drugs, and we did,” Roy said. “We had no complications and can now iterate up, reaching for the whole panel of kidney functions at the human scale.”

Source: University of California – San Francisco

Pig-to-human Kidney Xenotransplant is the Longest Successful One Yet

Photo by Natanael Melchor on Unsplash

Surgeons at NYU Langone Health have transplanted a genetically engineered pig kidney that continues to function well after 32 days in a man declared dead by neurologic criteria and maintained with a beating heart on ventilator support. This represents the longest period that a gene-edited pig kidney has functioned in a human, and the latest step toward the advent of an alternate, sustainable supply of organs for transplant.

Led by Robert Montgomery, MD, DPhil, the procedure was performed on July 24, 2023 and marks the fifth xenotransplant performed at NYU Langone. Observation is ongoing and the study will continue through mid-September 2023.

“This work demonstrates a pig kidney – with only one genetic modification and without experimental medications or devices – can replace the function of a human kidney for at least 32 days without being rejected,” said Dr Montgomery, who had previously performed the world’s first genetically modified pig kidney transplant into a human decedent in 2021.

Removing single troublesome gene

The first hurdle to overcome in xenotransplants is preventing so-called hyperacute rejection, which typically occurs just minutes after an animal organ is connected to the human circulatory system. By “knocking out” the gene that encodes the biomolecule known as alpha-gal, responsible for a rapid antibody-mediated rejection of pig organs by humans, immediate rejection has been avoided in all five xenotransplants at NYU Langone. Additionally, the pig’s thymus gland, which is responsible for educating the immune system, was embedded underneath the outer layer of the kidney to stave off novel, delayed immune responses. The combination of modifications has been shown to prevent rejection of the organ while preserving kidney function.

To ensure the body’s kidney function was sustained solely by the pig kidney, both of the transplant recipient’s native kidneys were surgically removed. One pig kidney was then transplanted and started producing urine immediately without any signs of hyperacute rejection. During the observation phase, intensive care clinical staff maintained the decedent on support while the pig kidney’s performance was monitored and sampled with weekly biopsies. Levels of creatinine, a bodily waste product found in the blood and an indicator of kidney function, were in the optimal range during the length of the study, and there was no evidence on biopsy of rejection.

The surgery was the latest in a larger study approved by a specific research ethics oversight board at NYU Langone and was performed after consultation with the New York State Department of Health. This important research, which study leaders say could save many lives in the future, was made possible by the family of a 57-year-old male who elected to donate his body after a brain death declaration and a circumstance in which his organs or tissues were not suitable for transplant.

A big leap toward a new organ source

“There are simply not enough organs available for everyone who needs one,” said Dr Montgomery, who received a hepatitis C-positive heart transplant himself in 2018. “Too many people are dying because of the lack of available organs, and I strongly believe xenotransplantation is a viable way to change that.”

The kidney and thymus gland used in this procedure were procured from a GalSafeTM pig, an animal engineered by Revivicor, Inc., a subsidiary of United Therapeutics Corporation. In December 2020, the U.S. Food and Drug Administration (FDA) approved the GalSafe pig as a potential source for human therapeutics as well as a food source for people with alpha-gal syndrome, a meat allergy caused by a tick bite.

Less may be more

While previous genetically engineered pig organ transplants have incorporated up to 10 genetic modifications, this latest study shows that a single-gene knockout pig kidney can still perform optimally for at least 32 days without rejection.

“We’ve now gathered more evidence to show that, at least in kidneys, just eliminating the gene that triggers a hyperacute rejection may be enough along with clinically approved immunosuppressive drugs to successfully manage the transplant in a human for optimal performance – potentially in the long-term,” said Dr Montgomery.

The NYU Langone team used standard transplant immunosuppression medications combined with enhanced screening of porcine cytomegalovirus (pCMV) in the donor pig to ensure safety. Recent studies have shown pCMV may affect organ performance and potentially trigger organ failure. No pCMV was detected after 32 days, and close surveillance of porcine endogenous retrovirus (PERV), along with six other viruses of interest, was performed.

Next steps

Monitoring of the pig kidney recipient will continue for another month with permission from the family, ethics committee approval and continued support from United Therapeutics. The additional data from the next several weeks will be analyzed further to develop a deeper understanding of this unique medical advance.

“We think using a pig already deemed safe by the FDA in combination with what we have found in our xenotransplantation research so far, gets us closer to the clinical trial phase,” said Dr Montgomery. “We know this has the potential to save thousands of lives, but we want to ensure the utmost safety and care as we move forward.”

Source: NYU Langone Health

Groote Schuur Performs Africa’s First ABO-incompatible Kidney Transplant

Anatomic model of a kidney
Photo by Robina Weermeijer on Unsplash

Eyewitness News reports that doctors at Groote Schuur Hospital have successfully performed Africa’s first incompatible kidney transplant. Known as ABO-incompatible (ABOi) transplants, these procedures are done when the donor’s blood type does not match the recipient’s – once a major contraindication.

The patient, a 35 year old woman named Chervon Meyer, received a kidney donation from her brother. She had been on dialysis for 10 years,

Over half a century ago, Groote Schuur had its mark on history with the world’s first human heart transplant led by Dr Christiaan Barnard.

Incompatible living kidney transplants have long been contraindicated because of the presence of isohaemagglutinins, natural antibodies reacting with non-self ABO antigens. Due to the growing demand for transplant organs, incompatible donations were investigated in order to expand the pool of possible donors. This has changed with the development of new desensitisation regimens over the past decades. These include immunoadsorption and plasmapheresis and the immunosuppressive protocol.

The improvements have been so great that, despite a lack of randomised trials, recent meta analysis found that there is no difference in terms of graft and patient’s survival between ABOi and ABO compatible kidney transplant, even in the long term.

As nephrologist Dr Zunaid Barday explains, this procedure made use of a Glycosorb filter which reduced many of the risks associated with desensitisation, such as plasma exchange weakening the immune system. It works by binding anti-A and anti-B antibodies, reducing their levels in blood plasma. While expensive, the filter is a much cheaper alternative in the long run compared to years of dialysis.

Source: Eyewitness News

Is Protein Restriction the Best Option after Kidney Transplant?

Anatomic model of a kidney
Photo by Robina Weermeijer on Unsplash

Scientists at Osaka Metropolitan University have challenged the conventional wisdom that low protein intake is essential for kidney disease patients with their recent study on the relationship between protein intake and skeletal muscle mass in kidney transplant recipients. Their findings were published in Clinical Nutrition.

Chronic kidney disease patients are known to have induced sarcopenia due to chronic inflammation, hypercatabolism, decreased nutrient intake, and decreased physical activity associated with impaired kidney function. A successful kidney transplantation is able to correct or improve many of those physiological and metabolic abnormalities, with the transplant recipients increasing skeletal muscle mass after receiving their new kidney. Since excessive protein intake worsens kidney function, it is commonly believed that patients with chronic kidney disease, including kidney transplant recipients, should limit protein intake to protect their kidneys. On the other hand, it has been suggested that severe protein restriction may worsen sarcopenia and adversely affect prognosis.

Since nutrition and exercise therapy are recommended to improve sarcopenia, protein intake is suspected to relate to recovery of skeletal muscle mass after kidney transplantation. However, few studies have examined the relationship between skeletal muscle mass and protein intake in kidney transplant recipients.

In order to fill this knowledge gap, a research group led by Drs Akihiro Kosoku and Tomoaki Iwai, and Professor Junji Uchida at Osaka Metropolitan University followed 64 kidney transplant recipients for 12 months after their procedure. They investigated the relationship between changes in skeletal muscle mass, as measured by bioelectrical impedance analysis, and protein intake from urine sample. The results showed that changes in skeletal muscle mass during this period were positively correlated with protein intake, and that insufficient protein intake resulted in decreased muscle mass.

Drs Iwai and Kosoku commented, “To improve the life expectancy of kidney transplant recipients, further research is needed to clarify the optimal protein intake to prevent either deterioration in kidney function or sarcopenia. We hope that nutritional guidance, including protein intake, will lead to improved life expectancy and prognosis.”

Source: Osaka Metropolitan University

Paediatric Kidney Transplants without Immunosuppressive Drugs

Anatomic model of a kidney
Photo by Robina Weermeijer on Unsplash

Stanford Medicine physicians have developed a way to provide paediatric kidney transplants without immunosuppressive drugs. Their key innovation is a safe method to transplant the donor’s immune system to the patient before surgeons implant the kidney.

The medical team has dubbed the two-transplant combination a “dual immune/solid organ transplant,” or DISOT. The first three DISOT cases, all performed at Lucile Packard Children’s Hospital Stanford were described in the New England Journal of Medicine, accompanied by an an editorial about the research.

The Stanford innovation removes the possibility that the recipient will experience immune rejection of their transplanted organ, the most common reason for a second organ transplant The new procedure also rids recipients of the substantial side effects of a lifetime of immune-suppressing medications, including increased risks for cancer, diabetes, infections and hypertension.

“Safely freeing patients from lifelong immunosuppression after a kidney transplant is possible.”

Alice Bertaina, MD, PhD, report’s lead author, associate professor of paediatrics, Stanford University

The first three DISOT patients were children with a rare immune disease, but the team is expanding the types of patients who could benefit. The protocol received FDA approval on May 27, 2022, for treating patients with a variety of conditions that affect the kidneys. Dr Bertaina anticipates that the protocol will eventually be available to many people needing kidney transplants, starting with children and young adults, and later expanding to older adults. The researchers also plan to investigate DISOT’s utility for other types of solid-organ transplants.

The scientific innovation from Dr Bertaina’s team has another important benefit: It enables safe transplantation between a donor and recipient whose immune systems are genetically half-matched, meaning children can receive stem cell and kidney donations from a parent.

The advance is especially meaningful for Jessica and Kyle Davenport of Muscle Shoals, Alabama. Their two children, both born with a rare and potentially deadly immune disease, are among the first recipients of DISOT: 8-year-old Kruz received transplants from Jessica, while his 7-year-old sister, Paizlee, received transplants from Kyle.

“They’ve healed and recovered, and are doing things we never thought would be possible,” said Jessica Davenport. After years of helping Kruz and Paizlee cope with severe immune deficiency and its attendant infection riskk as well as kidney dialysis, she and her husband are thrilled that their children have more normal lives.

The idea of transplanting a patient with their organ donor’s immune system has been around for decades, but it has been difficult to implement. Transplants of stem cells from bone marrow provide the patient with a genetically new immune system, as some of the bone marrow stem cells mature into immune cells in the blood. First developed for people with blood cancers, stem cell transplants carry the risk of the new immune cells attacking the recipient’s body, a potentially lethal complication called graft-versus-host disease.

Source: Stanford Medicine

Lifestyle Changes Key for Older Kidney Transplant Recipients

Photo by Robina Weermeijer on Unsplash

Researchers discovered that deaths among kidney transplant recipients due to factors other than organ rejection is the leading cause for transplanted kidney loss. Their findings, published in Transplantation Direct, revealed that only one in four transplanted kidney losses were caused by organ rejection.

“Immunosuppression medication to prevent rejection is often the focus when caring for patients post transplant. But this study highlights the increased risk of death from cancer and infection for transplant patients, especially those who are older and have diabetes,” said Andrew Bentall, MB, ChB, MD, the study’s co-first author.

The study involved 5752 patients who underwent a kidney transplant between 2006 and 2018. Of those, 691 died with a functioning kidney. Researchers found that 20% of these patients died from cancer; 19.7%, infection; and 12.6%, cardiac disease.

Another 553 patients lost their transplant due to the failure of a transplanted kidney. Of these patients, 38.7% of the patients’ kidneys failed due to rejection; 18.6%, glomerular diseases; and 13.9%, tubular injury.

Two types of recipients were found to be most vulnerable after transplant. The first are younger, nondiabetic patients who develop kidney failure due to organ rejection. The second group includes older, often diabetic patients who are at risk of death due to causes not associated with organ rejection, including cancer, infections and heart disease.

Care providers need to treat these two populations differently to minimise risks, according to Dr Bentall. For younger patients, that includes focusing on immunosuppression medication to prevent rejection. For older, often diabetic patients, it is critical to address chronic health issues, such as obesity, high blood pressure and diabetes. Focusing on these lifestyle changes is critical for improving long-term outcomes for kidney transplant recipients.

“It is important for these older patients that care providers emphasise the need for ongoing lifestyle changes that address obesity, high blood pressure and diabetes. Those include losing weight, exercising and new strategies for managing diabetes,” he said. “Making those changes could potentially impact the patient’s life and kidney outcomes more than immunosuppression therapies.”

Source: Mayo Clinic