One of the most threatening complications among patients hospitalized due to acute COVID-19 is the injury to several internal organs of the body. Of these, kidney injury is a highly feared outcome which can also increase the chances of novel coronavirus-related deaths. In a new study, an international team of researchers has identified a protein that is most likely the cause behind kidney damage in COVID-19 patients.
According to a study led by the University of Michigan, high levels of soluble urokinase plasminogen activator receptor (suPAR)—a protein produced by the blood and serves as the biomarker for the immune and inflammatory activity in the human body—was closely connected with the kidney injury among people infected with the SARS-CoV-2 virus and required hospitalization.
"We don't know exactly why patients with severe COVID-19 have a high rate of kidney injury," said Dr. Salim Hayek, senior author of the study. "It is, however, becoming clearer that a hyperactive immune system plays a major role in the morbidity of COVID-19, including kidney-related complications."
Identifying the 'Culprit'
The authors tested the levels of suPAR of 352 study participants who contracted the disease and were admitted to the hospital on account of it. Nearly 25 percent of the participants suffered severe kidney damage while in hospital. Their median suPAR levels were over 60 percent higher in comparison to other participants.
Also, the potential need for life-saving dialysis was 20-fold higher among patients with the highest levels of suPAR. On the whole, the medial suPAR levels of hospitalized participants with severe COVID-19 were nearly three times higher when compared to healthy individuals.
"SuPAR is an immune-derived circulating factor we've seen contribute to kidney injury in thousands of patients," said Dr. Jochen Reiser, co-author of the study. "RNA viruses such as HIV and SARS-CoV-2 elicit a suPAR response of the innate immune system leading to a rise in blood suPAR levels. If there is a hyperinflammatory suPAR response, kidney cells may be damaged," explained Dr. Reiser.
Negotiating Kidney Injuries In COVID-19 Patients
Dr. Subramaniam Pennathur, co-author of the study, stressed that recording suPAR levels at the time of admission to hospitals may serve as an important predictor of Acute kidney injury (AKI) during the course of their treatment periods and be consequential for care in the future.
"For example, obtaining suPAR levels may allow us to risk-stratify, i.e., identify high-risk patients early, and institute appropriate preventive treatment, thereby reducing AKI risk and improving COVID-19 outcomes," he said. Dr. Pennathur added that treatments focused on interrupting the suPAR pathway could also be considered for the therapeutic and preventive care of coronavirus-caused AKI.
"We're preparing to launch the first clinical trial targeting suPAR to prevent COVID-19 related kidney injury, and by doing so hope to alleviate the burden of kidney disease in both COVID-19 and non-COVID-19 patients with high suPAR levels," concluded Dr. Hayek.