Researchers have found a concerning link between certain heart cells and the spike protein of SARS-CoV-2, the virus that causes COVID-19. The spike protein appears to change cells in the small blood vessels around the heart, disrupting their regular function.
The pre-print study, meaning it is yet to be peer-reviewed, was presented at the European Society of Cardiology Congress and shows that the spike protein binds to cells called pericytes. These cells line the small vessels of the heart as well as other places around the human body. When the binding occurs, the pericytes begin to release chemicals that cause inflammation to the organ.
In the study, the team took small vessel cells from the heart and exposed them to the spike protein. The protein is used by the virus to attach itself to the cells. Once the virus's position is secured, the virus merges with the cell membrane, releasing its genetic material. This highjacks the cellular machinery, which begins replicating the virus, which then bursts out and spreads to other cells.
If the spike protein alone is capable of affecting cells' behavior, it's concerning. It suggests that even cells that are not being infected can be harmed by the virus, making it more difficult to treat. The team found that by blocking the CD147 receptor on those cells, they reduce the effect of the spike protein on the pericytes, although there was still inflammation.
Pericytes are found all over the body, including the brain and central nervous system. If the mechanism can be stopped in patients it might reduce the complication arising from COVID-19, and further investigations might produce better ways to stop the spike protein.
“This mechanism has the potential to spread cellular and organ injury beyond the infection sites and may have important clinical implications. For instance, in patients with disrupted endothelial barrier and increased vascular permeability due to underlying diseases, such as hypertension, diabetes, and severe obesity, S protein molecules could easily spread to the PC compartment and cause, or exacerbate, microvascular injury," the authors wrote in the paper. "Blocking the CD147 receptor may help protect the vasculature of the most vulnerable patients from infection and the collateral damage caused by the S protein."
There is a lot of uncertainties on the most effective ways to treat COVID-19; for this reason, prophylaxis approaches such as vaccination, social distancing, and masks remain paramount. The immediate and long-term effects of the virus on many organs are still not fully understood.
“Covid-19 has presented an unprecedented challenge for the cardiovascular research community. There is still a lot that is unknown relating to how the virus can impact our health in the long term, but this research brings us one step closer to better understanding how Covid-19 affects the heart and circulatory system and may ultimately lead to new ways to protect the heart," Professor James Leiper, Associate Medical Director of the British Heart Foundation, said.