Glowing urine may replace the biopsy needle: In detecting organ transplant rejection, a new nanoparticle has proven much faster and more thorough in the lab than a biopsy. When T cells mount their first attack on the organ’s cells, the nanoparticle sends an alarm signal into the urine that makes it fluoresce.
Too often, it’s only after a transplanted organ has sustained serious damage that a biopsy reveals the organ is in rejection. A new screening method using sensor particles and a urine test could catch rejection much earlier, more comprehensively, and without a biopsy needle.
When the body’s immune system has just begun attacking cells of a transplanted organ, the new method’s particles send a fluorescent signal into the urine. In a new study, researchers at the Georgia Institute of Technology and Emory University validated the method in a mouse model, and they have engineered the sensor with highly biocompatible components, which could make the path to potential future trials easier.
A patient may feel fine, and a biopsy may look deceptively clean when T cells have already begun attacking a transplanted organ. The sensor particle, a nanoparticle, detects a T cell weapon, an enzyme called granzyme B, that pushes a transplanted organ’s cells into the self-destruction process called apoptosis.
“Before any organ damage can happen, T cells have to produce granzyme B, which is why this is an early detection method,” said Gabe Kwong, a co-principal investigator in the study and an assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University.
“This is sensitive enough to possibly detect budding rejection before you see significant injury to the transplanted organ and that could help clinicians treat early to prevent damage,” said Dr. Andrew Adams, co-principal investigator and an associate professor of surgery at Emory University School of Medicine. “Right now, most tests are aimed at organ dysfunction, and sometimes they don’t signal there is a problem until organ function is below 50 percent.”
Kwong and Adams published the study’s results in the journal Nature Biomedical Engineering on February 18, 2019. The research was funded by the National Institutes of Health, the National Science Foundation and the Burroughs Wellcome Fund.
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