A relatively simple and rapid blood test may serve as a predictor for severe complications or death due to Covid-19, according to a recent study by scientists at Washington University School of Medicine in St Louis (WUSTL). This opens up possibilities for more effective clinical trial designs and monitoring of disease progression.
About the Blood Test
This innovative blood test assesses the levels of mitochondrial DNA (mtDNA) in the body. Mitochondrial DNA is a distinct type of DNA molecule situated inside the cells’ energy factories, known as mitochondria. When mtDNA spills into the bloodstream, it indicates that a violent form of cell death is occurring within the body.
The Study and its Observations
In their research, the WUSTL scientific team documented the mtDNA levels of 97 Covid-19 patients upon the first day of hospitalization. They noticed elevated mtDNA levels in patients who were later admitted to Intensive Care Units (ICUs), required intubation, or died due to the infection. This correlation was observed regardless of the patients’ age, gender, or pre-existing health conditions.
Significance of the Test
The blood test offers a way to predict the severity of the disease and could play a critical role in strategizing clinical trials. For instance, identifying patients who might show improved response to specific investigational treatments becomes easier. Also, the test can serve as a tool for evaluating the effectiveness of new therapies by monitoring decreases in mtDNA levels. The test forecasted outcomes as accurately as, or better than, the existing inflammation markers typically measured in Covid patients.
Difference Between Mitochondrial DNA and Other Markers of Inflammation
Unlike most other inflammation markers investigated in Covid-19 patients, which are general indicators of systemic inflammation, mtDNA is more closely related to cell death-specific inflammation. The body’s natural response to injury or infection, including trauma, surgery, burns, and cancer, is inflammation. Specific proteins released into the bloodstream during inflammation can serve as systemic inflammatory markers if their concentrations fluctuate by at least 25%.
About Mitochondrial DNA
Mitochondrial DNA, encased within the mitochondria – the energy factories of the cells, is a small circular chromosome. They create cellular energy in the form of adenosine triphosphate (ATP), giving them the tag of ‘power houses’ of the cell. Mitochondrial DNA differs from nuclear DNA in its inheritance pattern and structure. While it is small, circular, and contains around 16,500 base pairs, nuclear DNA is linear with about 3.3 billion DNA base pairs. Mitochondrial DNA is inherited solely from the mother, whereas nuclear DNA comes from both parents. Defects or mutations in mtDNA can result in mitochondrial disease, causing inadequate energy production in various parts of the body like muscles, brain, and kidneys.