Whether a bioartificial kidney containing billions of donor kidney cells will help intensive care patients with kidney failure survive is under study at the Medical College of Georgia.
MCG Medical Center has joined a study taking place in intensive care units across the country to evaluate the efficacy of the renal assist device, says Dr. Harold M. Szerlip, MCG nephrologist specializing in acute renal failure and a principal investigator on the study.
“If you have renal failure in the ICU, your mortality is extremely high,” Dr. Szerlip says. “Anywhere from 50 to 70 percent of those patients die and over the past 20 years, despite dialysis, that has not changed much.”
He hopes the new device, developed by Dr. H. David Humes at the University of Michigan, can help turn the tide for some patients by more closely mimicking the many important functions of the kidney.
In ICUs today, doctors may opt for newer continuous dialysis therapies in which patients with renal failure receive dialysis around the clock. With more standard intermittent therapy, patients get several hours of dialysis three to four times a week.
Since kidneys are constantly working, it may seem logical that longer dialysis is a better option, but, in fact, the issue has not been scientifically analyzed. This month, Dr. Szerlip and MCG Medical Center will join a Department of Veterans Affairs and National Institutes of Health study to do just that.
But no matter how long dialysis is given, it only replicates a fraction of the work of the kidneys, which are involved in diverse functions ranging from regulating vitamin D to modulating the immune response. “Existing forms of dialysis have only replaced the ability of the kidneys to rid the body of waste products and correct abnormalities in blood chemistry; they don’t replace kidney function, ” says Dr. Szerlip.
The kidneys also secrete hormones, help determine how the body metabolizes calcium and phosphorus, stimulate red blood cell production, play a role in blood pressure regulation and clear and metabolize cytokines that help direct the immune system.
The new device for kidney failure adds billions of kidney cells that can perform many of these important kidney functions. Human proximal tubule cells are collected from kidneys obtained by the National Disease Research Interchange, a nonprofit organization that provides researchers with tissues and organs anatomically unsuitable for transplant.
The cells are grown into the walls of thousands of hollow fibers contained in a cartridge similar to those used for traditional dialysis.
With dialysis, a patient’s blood runs through the fibers and a solution with the normal composition of electrolytes runs on the outside. Through osmosis, waste products in the blood migrate across the fibers into the solution. The now-dirty solution is discarded and the cleaner blood is given back to the patient. In the study, all patients receive this standard approach to cleaning the blood.