Medical Xpress, June 26, 2017
Between 15 and 20 percent of black people carry a genetic mutation that puts them at risk for certain chronic kidney disease, but only about half of them develop the illness — a variance that long has puzzled researchers. Now a study has found that the gene mutation’s toxic effects require higher than normal levels of a protein called suPAR to trigger the onset and progression of the disease.
The results of the study, published in a research article in the journal Nature Medicine today, could lead soon to new treatments for chronic kidney disease that target these risk factors, according to Dr. Jochen Reiser, the senior author of the paper. Reiser is the chairperson of the Department of Internal Medicine and Ralph C. Brown MD Professor of Medicine at Rush University Medical Center, Chicago.
Chronic kidney disease — or CKD for short — is a progressive failure of function that prevents kidneys from fulfilling their role filtering waste from the blood stream. Nearly 17 percent of people in the U.S. have chronic kidney disease, and approximately 4 percent require dialysis and/or a kidney transplant due to kidney failure. Currently, there are no drugs that can treat CKD in an effective way.
For the study recounted in the Nature Medicine paper, Reiser worked with a team that included researchers at Emory University, Harvard University, Johns Hopkins University, the National Institute of Health, Ruprecht Karls University of Heidelberg, the Israel Institute of Technology and others.
Reiser has spent his career studying a scarring type of chronic kidney disease, focal segmental glomerulosclerosis. In past studies, he discovered that suPAR not only is a marker for kidney disease, but also a likely cause.
“What we are learning today is that suPAR in a general way is to kidneys what cholesterol is to the heart, a substance that can cause damage if levels rise too high, or a substance that can likely make many forms of kidney disease worse,” Reiser says. “Based on these fundamental insights, suPAR level testing may become a routine test at many institutions around the world.”
Like cholesterol, suPAR levels vary from person to person. Some environmental factors can contribute significantly to elevated suPAR levels. “Lifestyle is a big factor, bigger than we thought,” Reiser says.
Smoking, weight gain and even frequent infections can add up and send suPAR to dangerous heights. Weight loss and smoking cessation can help bring levels down, but once elevated, suPAR may not recede to a healthy level again, said Dr. Melissa Tracy, co-author of the study and an associate professor of cardiology at Rush. People at genetic risk for kidney disease should aim to live a healthy life to keep suPAR levels low.