Researchers at the University of California San Francisco have developed an implantable bioreactor that may pave the way for artificial kidneys. Dialysis and kidney transplants both have significant disadvantages for patients with kidney failure, and so scientists are trying to develop a lab created kidney that would not require harsh immunosuppression or a donor kidney. This implantable bioreactor may be a step in the right direction, and it includes a type of cell found in the kidney which is protected from the immune system behind a silicon membrane. Blood can flow through the device, and so far the researchers have shown that the cells inside can survive when it is implanted into pigs for at least seven days. The researchers hope to develop the device further, including multiple cell types from the kidney, so that it begins to fulfill the roles of the kidney in the body.
Kidney failure patients are often treated with dialysis, but this is a poor substitute for a working kidney, and requires patients to attend a clinic several times a week. A kidney transplant is the eventual goal for many such patients, but donor kidneys are in short supply and waiting lists are long. Moreover, even when a donor kidney becomes available, the recipient must take strong immunosuppressant drugs for the remainder of their lives.
These issues have prompted researchers to begin to develop artificial kidneys in the lab. Such constructs may use a patient’s own kidney cells, if available, which could negate the need for immunosuppression. Other strategies may involve protecting the kidney cells using physical barriers to exclude immune cells.
This latest advance comes in the form of an implantable bioreactor that includes a type of kidney cell, a proximal tubule cell, which is ordinarily involved in regulating water levels in the body, as a proof-of-concept. “We are focused on safely replicating the key functions of a kidney,” said Shuvo Roy, a researcher involved in the study. “The bioartificial kidney will make treatment for kidney disease more effective and also much more tolerable and comfortable.”
The bioreactor is designed to be directly connected to nearby blood vessels, allowing blood to flow through it. However, silicon membranes protect the kidney cells within from immune attack. So far, the device could support cell survival for at least seven days when the bioreactors were implanted in pigs, suggesting that the technique could work when additional cell types are included.
“We needed to prove that a functional bioreactor will not require immunosuppressant drugs, and we did,” said Roy. “We had no complications and can now iterate up, reaching for the whole panel of kidney functions at the human scale.”
Study in journal Nature Communications: Feasibility of an implantable bioreactor for renal cell therapy using silicon nanopore membranes