SAN FRANCISCO: A team of researchers found that the genes of the mitochondria, the energy producers of the human body cells, can be negatively impacted by the coronavirus, leading to dysfunction in multiple organs beyond the lungs, a new study has shown.
Mitochondria are found in every cell in human bodies.
The genes responsible for generating mitochondria are dispersed across both the nuclear DNA located in the nucleus of our cells and the mitochondrial DNA (mtDNA) located within each mitochondrion, according to the study published in the journal Science Translational Medicine.
To understand how SARS-CoV-2 impacts mitochondria, researchers analysed a combination of nasopharyngeal and autopsy tissues from affected patients and animal models.
“The tissue samples from human patients allowed us to look at how mitochondrial gene expression was affected at the onset and end of disease progression, while animal models allowed us to fill in the blanks and look at the progression of gene expression differences over time,” said the study’s first author Joseph Guarnieri, PhD.
The study found that in autopsy tissue, mitochondrial gene expression had recovered in the lungs, but mitochondrial function remained suppressed in the heart as well as the kidneys and liver.
Even though no SARS-CoV-2 was found in the brain when researchers studied animal models and measured the time when the viral load was at its peak in the lungs, mitochondrial gene expression was suppressed in the cerebellum.
Taken together, these findings showed that host cells respond to initial infection in a way that involves the lungs, but that mitochondrial function in the lungs is restored over time, whereas mitochondrial function in other organs, particularly the heart, remains impaired.
“This study provides us with strong evidence that we need to stop looking at Covid-19 as strictly an upper respiratory disease and start viewing it as a systemic disorder that impacts multiple organs,” said co-senior author Douglas C. Wallace, PhD.
“The continued dysfunction we observed in organs other than the lungs suggests that mitochondrial dysfunction could be causing long-term damage to the internal organs of these patients,” he added.