The Clot Thickens!

The dynamics of a job are something that you might already be familiar with. Your boss gives you a set of guidelines and instructions to follow for your task for the week and you follow it to the T. Our body being the sophisticated machine that it is works on the same principle for carrying our various processes including clotting of our bleeding wounds.   In this scenario, a gene called the F5 gene acts as the boss, which provides instructions for making a protein called coagulation factor V. The task of creating the coagulation system (series of reactions causing formation of blood clots) is entrusted to a group of proteins that act as the employees and are called coagulation factors, which create the coagulation system as the task (series of reactions causing formation of blood clots).

The factor V protein is inactive in the bloodstream until there is an injury and hence, a need for the coagulation system. Once this protein is activated, it interacts with another coagulation factor called factor X. These factors together, once active, form a complex that converts a coagulation protein called prothrombin (inactive) to thrombin (active). Thrombin then converts another protein called fibrinogen to fibrin and this material forms the clot. Factor V also helps regulate the clotting system by interacting with activated protein C (APC). APC inactivates factor V by cutting it at specific sites. This slows down clotting and prevents the clots from growing too large.

Wouldn’t you think factor V and the coagulation system are excellent employees? This mechanism of our body to protect itself from any damage is surely fascinating. However, the ongoing pandemic has added a completely different dimension to this set up. Covid-19 has provided doctors and researchers with a lot of new and previously unknown information about the virus and its possible manifestations or complications. One such lethal complication is high levels of Factor V which have been observed to have increased in severe cases of Covid patients. Patients who have been hospitalized with severe viral infections and have high levels of factor V have been found to be at elevated risk of blood clots like deep vein thrombosis or pulmonary embolism. Blood clots in catheters, arteries, lungs and even toes are possible. In contrast, some critical patients with Covid-19 and  having low levels of Factor V have been observed to be at increased risk of death from a type of coagulopathy that is similar to disseminated intravascular coagulation (DIC). DIC is a type of abnormality that causes blood clots to form in small vessels in the body leading to exhaustion of factors and proteins that control clotting. This is a devastating and often fatal condition.

Because of the unpredictability of the virus, the elevation in factor V induced by Covid-19 has come as a shock to many doctors and health workers. Elizabeth Van Cott, a senior study author and Harvard Medical school professor of pathology at Mass General said “Aside from Covid-19, I’ve never seen anything else cause markedly elevated factor V, and I’ve been doing this for 25 years.” However, findings based on Covid-19 patients in the Mass General intensive care units have identified the cause of these clots and potential anticoagulation therapies for at-risk patients.

Hence, the bottom line is that factor V is an incredible employee, he just so happens to be working in overdrive during the pandemic to save his job like the rest of us! 

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