In a groundbreaking development that could potentially revolutionize the treatment of kidney failure, scientists at the University of California, San Francisco (UCSF), have unveiled a promising approach that could liberate patients from the burdens of dialysis and the need for immune-suppressing drugs post-transplantation. This groundbreaking research showcases the successful survival of kidney cells within an implantable device known as a bioreactor within a pig's body while emulating critical kidney functions. The device functions unobtrusively, akin to a pacemaker, without inciting the recipient's immune system into defensive mode.

Published in Nature Communications, these findings represent a significant leap forward for "The Kidney Project," a collaborative initiative helmed jointly by Dr. Shuvo Roy, PhD, the Technical Director at UCSF, and Dr. William H. Fissell, MD, the Medical Director at Vanderbilt University Medical Center.

The ultimate ambition of this research initiative is to populate the bioreactor with diverse kidney cells capable of executing pivotal tasks such as maintaining fluid balance within the body and regulating blood pressure by releasing hormones. The aim is to engineer a human-scale device that could dramatically enhance the current standard of care offered by dialysis, a life-preserving yet imperfect substitute for fully functioning kidneys. In the United States alone, more than half a million individuals rely on dialysis treatments several times a week, with a limited number fortunate enough to secure kidney transplants, of which only approximately 20,000 are performed annually. An implantable kidney could change the lives of countless patients grappling with kidney disease.

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^{Explanation of The Kidney Project's goals and some of its previous work (2021)}

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

Drawing inspiration from nature and refining their concepts through rigorous scientific inquiry, Roy and his colleagues engineered the bioreactor to seamlessly integrate with blood vessels and veins, allowing unimpeded flow of vital nutrients and oxygen, mirroring the behavior of a transplanted human kidney. Silicon membranes provide protection for the kidney cells housed within the bioreactor, shielding them from the potential assaults of the recipient's immune cells.

As a test case, the team employed proximal tubule cells, a type of kidney cell responsible for water regulation—co-author H. David Humes, MD, from the University of Michigan, had previously harnessed these cells to offer life-saving assistance to intensive care unit patients reliant on dialysis.

Following the transplantation, a seven-day observation period for the kidney cells and the host animals yielded promising results with no discernible setbacks. The next phase of this research will encompass month-long trials in compliance with the United States 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.”