COVID-19 Patients Have Low Oxygen Levels Due to Damaged Blood Cells, Finds Study

Researchers from the University of Colorado Anschutz Medical Campus (Aurora, CO, USA) and Columbia University (New York, NY, USA) conducted a study combining state-of-the-art metabolomics, proteomics, and lipidomics approaches to investigate the impact of COVID-19 on RBCs from 23 healthy subjects and 29 molecularly-diagnosed COVID-19 patients. The researchers found that the RBCs from COVID-19 patients had increased levels of glycolytic intermediates, accompanied by oxidation and fragmentation of ankyrin, spectrin beta, and the N-terminal cytosolic domain of band 3 (AE1). Significantly altered lipid metabolism was also observed, especially short and medium chain saturated fatty acids, acyl-carnitines, and sphingolipids. However, there were no alterations of clinical hematological parameters, such as RBC count, hematocrit, and mean corpuscular hemoglobin concentration, with only minor increases in mean corpuscular volume.

According to the researchers, the findings suggested a significant impact of SARS-CoV-2 infection on RBC structural membrane homeostasis at the protein and lipid levels. The increases in RBC glycolytic metabolites were consistent with a theoretically improved capacity of hemoglobin to off-load oxygen as a function of allosteric modulation by high-energy phosphate compounds, perhaps to counteract COVID-19-induced hypoxia. Conversely, because the N-terminus of AE1 stabilizes deoxyhemoglobin and finely tunes oxygen off-loading, RBCs from COVID-19 patients may be incapable of responding to environmental variations in hemoglobin oxygen saturation when traveling from the lungs to peripheral capillaries and, as such, may have a compromised capacity to transport and deliver oxygen.

"Since red cells circulate for up to 120 days, this could also help explain why it can take months to recover from the virus ... until enough new red cells without this damage are made and circulate," senior researcher Angelo D'Alessandro of the University of Colorado Anschutz Medical Campus told Reuters.

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University of Colorado Anschutz Medical Campus
Columbia University