ABOVE: A hyperactive bradykinin system permits fluid, shown in yellow, to leak out of a blood vessel and allows immune cells, shown in purple, to squeeze out as well.
JASON SMITH/ORNL, US DEPARTMENT OF ENERGY
On a Sunday afternoon in mid-April this year, Daniel Jacobson, a computational systems biologist at Oak Ridge National Laboratory in Tennessee, was looking at gene expression data from the lung fluid of COVID-19 patients on his computer screen when he spotted something striking—the expression of genes for key enzymes in the renin-angiotensin system (RAS), involved in blood pressure regulation and fluid balance, was askew.
Jacobson followed this abnormal RAS in the lung fluid samples to the kinin cascade, an inflammatory pathway that is tightly regulated by the RAS. He found that the kinin system—in which a key peptide, bradykinin, causes blood vessels to leak and fluid to accumulate in tissues and organs—was thrown out of balance ...
