One of the most troubling things about COVID-19 has been the inability of medical providers to determine which patients will develop life-threatening complications. We know some risk factors like age and pre-existing medical conditions play an important role, but there are many cases where younger, seemingly healthy patients ultimately face severe outcomes, such as extended stays in the ICU, being put on a ventilator or even death. A new study from Washington University School of Medicine may have found an easily implementable way for hospitals to determine who is most at risk for such complications within the first day of hospitalization.
Published in JCI Insight, the study focuses on a rapid blood test that measures levels of mitochrondiral DNA, a unique molecule that normally is found inside cells’ mitochondria. “The mitochondria is responsible for converting energy in a cell, but with both viral and bacterial infections, we know it becomes dysfunctional,” explains senior co-author Andrew Gelman, Ph.D., the Jacqueline G. and William E. Maritz Endowed Chair in Immunology and Oncology in the Department of Surgery. “It breaks down, and the DNA is released. Other research has shown that this type of cell death is an indicator of a patient’s inability to fight off infection.”
Along with his senior co-author, assistant professor of medicine Hrishikesh Kulkarni, M.D., and colleagues, Gelman looked at the levels of mitochondrial DNA in 97 newly hospitalized COVID-19 patients at Barnes-Jewish Hospital. Levels were about 10 times higher in patients who developed severe lung infections. It also was discovered that those with more mitochondrial DNA in their blood were almost six times more likely to be intubated, three times more likely to end up in the ICU and almost twice as likely to die.
Physicians may be able to use this information to determine which patients to administer certain interventions, which could relieve strain on overly burdened hospitals. The blood test can be administered before patients require the use of resources like ICU beds or ventilators. “We found a high level of mitochondrial DNA is independent of other risk factors for severe cases of COVID-19,” Gelman says. “That offers a major advantage. Therapies like monoclonal antibodies are in short supply. Tests like this could help make decisions and predictions about who will need which treatments.”
The researchers also determined that the necessary blood test can be easily implemented in most hospital settings. It uses the same machinery that processes the standard PCR test for COVID-19. It also only requires a small amount of blood, and the DNA does not have to be extracted, which simplifies and expedites the process. “Patients are already getting blood tests frequently, we’ve made the test adaptable to a clinical setting, and we can easily train technicians to do it,” Gelman notes.
The next step for the study is to expand to other hospitals around the country to determine if the results at Barnes-Jewish are accurate. Gelman is hopeful that the research will help determine the effectiveness of investigational treatments for COVID-19. “The mitochondrial DNA level can be checked throughout a patient’s care, allowing doctors to see how they are responding to different interventions,” he says. “As a marker for therapeutic responses, it could be a way to evaluate clinical trials of new drugs. We are excited to roll out this test in other medical centers as a way to fight COVID-19.”