Fluorescent urine that detects organ transplant compatibility

Photo Credit: Global Panorama

Often, an organ transplantation is the only life-saving treatment for organ failure. The process of transplantation requires matching the organs of the donor with the requirements of the recipients. It is only after medical compatibility is established, that the organ procurement from a living or a deceased donor can occur.

In what seems like an incredible invention in the field of biomedical sciences, a team of researchers from the Georgia Institute of Technology and the Emory University have found a non-invasive technique of determining organ rejection. The method uses nanoparticles as biomarkers. As soon as the body’s immune system attacks the transplanted organ, the nanoparticles make urine glow, determining transplant rejection at a much earlier stage.

The early detection of rejection or acceptance is critically important for the success of a transplant and the health of the recipient. Generally, a core biopsy or tissue culture is the standard method of determining organ compatibility. This method is invasive and has a very limited prediction powers. It is also frequently seen that the transplanted organ is already subjected to serious damage by the time a biopsy or the tissue culture reveals results.

Thus, the development of this new screening method is essential in terms of early detection of organ rejection without the use of needle.

The nanoparticles have been engineered by putting together iron oxide in the center of a ball, double coated with dextran (a sugar) and polyethylene glycol (a chemical commonly found in laxatives). This prevents the body from disposing off the nanoparticles too soon. Bristle like projections, structured out of amino acids, stick out of the iron ball with sensor or fluorescent ‘reporter’ molecules attached to the tips.  

As soon as the body’s immune system attacks the transplanted organ, the nanoparticles make urine glow, determining transplant rejection at a much earlier stage.

The particles are injected intravenously.  The size of the particles have been constructed in a manner that they are too big to get collected in tissues or to pass out of the body, but are small enough to accumulate in the tissues of undetermined transplanted organs, in order to keep a check on medical incompatibility.

The nanoparticle detects the presence of a T cell (a cell part of the immune system), that immediately secretes an enzyme called granzyme B, forcing the transplanted organ cells to severe its amino acid strands. This triggers the organ cell to cause self-destruction and die, a process known as apoptosis.
Gabe Kwong, co-principal investigator in the study, and assistant professor in the Wallace H. Coulter Department of Biomedical Engineering at Georgia Tech and Emory University said, “this is an early detection method, for the simple reason that the nanoparticles force T cells produce granzyme B, before any organ damage can occur.”

The procedure has been successfully tested on mice. The researchers have now advanced to develop highly efficient biocompatible sensors, in order to make this technique easier to use in future trials.

This post was writte by Shruti Sundaresan and edited by Karolina Zieba.

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