Proactive Surveillance for “Fending off ” Rejection
Rejection can occur at any time after a transplant — immediately after the transplant or years down the road. It is often silent, and patients don’t necessarily experience symptoms. Because of this, patients can feel constant anxiety in ‘not knowing’ if their body is rejecting their transplanted organ. Transplant recipients wait years for a transplant, and yet after they’ve received a new chance at a better life, their remaining years are filled with fear of having to go back to a tethered life on dialysis.
Yet, if rejection is detected early, physicians can deliver anti-rejection therapies to improve the patient’s health—and prevent them from losing the donated organ. Conversely, if rejection is ignored, it could be life threatening.
Post Transplant Surveillance with donor-derived cell-free DNA (dd-cfDNA)
Research has shown that donor-derived cell-free DNA (dd-cfDNA) found in a patient’s plasma may be used as a “liquid biopsy” marker for identifying solid organ transplant rejection. Donor-derived cell-free DNA is released when the donated organ is attacked by either antibody or cell-mediated rejection processes.
Historically, routine surveillance of kidney transplant allografts relied on imperfect non-invasive biomarkers such as creatinine and urinary indices, while the gold standard allograft biopsy is associated with risk of bleeding, organ injury and sampling errors. Donor derived cell free DNA (dd-cfDNA) is being employed as a biomarker that addresses limitations of these surveillance methods, albeit has inherent drawbacks. This review provides an update on the enhanced understanding of dd-cfDNA and its expanded use beyond the conventional indication of detecting allograft rejection.
Electronic Device Continuously Monitors Transplanted Organs in Real Time
Northwestern University researchers have developed the first electronic device for continuously monitoring the health of transplanted organs in real time. This device is tiny. At only 0.3 centimeters wide, 0.7 centimeters long and 220 microns thick, it is smaller than a pinky fingernail, and the width of a single hair
Sitting directly on a transplanted kidney, the ultrathin, soft implant can detect temperature irregularities associated with inflammation and other body responses that arise with transplant rejection. Then, it alerts the patient or physician by wirelessly (via Bluetooth) streaming data to a nearby smartphone or tablet.
Video Link: https://youtu.be/L_dWGYpgRnQ
Current Monitoring Challenges
For the more than 250,000 people in the U.S. living with a transplanted kidney, monitoring their organ’s health is an ongoing journey. The easiest way to monitor kidney health is through measuring certain markers in the blood. By tracking the patient’s creatinine and blood urea nitrogen levels, physicians can gain insight into kidney function. But creatinine and blood urea nitrogen levels can fluctuate for reasons unrelated to organ rejection, so tracking these biomarkers is neither sensitive nor specific, sometimes leading to false negatives or positives.
The current “gold standard” for detecting rejection is a biopsy, in which a physician uses a long needle to extract a tissue sample from the transplanted organ and then analyzes the sample for signs of impending rejection. But invasive procedures like biopsies carry risks of multiple complications, including bleeding, infection, pain and even inadvertent damage to nearby tissues.
Northwestern’s new (first of it’s kind) bioelectronic implant, by contrast, monitors something much simpler and more reliable: temperature. Because temperature increases typically accompany inflammation, the researchers hypothesized that sensing anomalous temperature increases and unusual variations in temperature might provide an early warning sign for potential transplant rejection—as much as three weeks before creatinine and blood urea nitrogen increase.