A recently discovered molecule may have the potential to protect the kidneys from failing after injury, according to new research.
For the study, mice were genetically engineered to express higher-than-normal levels of the natural molecule hepatic growth factor (HGF) or another natural factor called parathyroid hormone-related protein (PTHrP). Both groups of mice developed normal kidney functions, thus allowing the researchers to study how the high levels of HGF and PTHrP would affect kidney recovery after blood flow to the kidney was temporarily interrupted.
Scientists found the mice that had not been genetically modified had their kidney functions sharply reduced, and the function worsened over time following the reduction in blood supply. In contrast, the mice with higher levels of HGF experienced a much lower degree of kidney damage after injury. Two days later, their kidney functions had almost completely returned to normal. Mice with high levels of HGF were also much more likely to survive after kidney injuries than mice with normal levels.
Kidney failure commonly occurs in intensive care units following a major surgery, and currently, patients who experience it have a mortality rate of about 50 percent. The researchers say it is a major cause of death in seriously ill patients. They explain acute renal failure -- or kidney failure -- occurs because of renal tubule cell death. When the researchers examined the kidneys of the genetically modified mice, they discovered the high level of HGF actually protected the renal tubule cells. These cells play an important role in the kidney's ability to produce urine.
Researchers write, "The fact that the kidneys developed normally in high-HGF and high-PTHrP mice is an important step forward in assessing the protective effects of these factors against cell damage." They call it "remarkable" that the HGF does not seem to negatively affect kidney development, yet it has a "striking protective effect" against kidney failure.
"We conclude that gene delivery of HGF to the proximal tubule may be an interesting approach in designing future strategies aimed at the treatment and prevention of [acute renal failure]," they write.