The recent analysis of patients suffering from the Covid-19 infection has put forth a new phenomenon known as the ‘bradykinin storm’. This phenomenon might shed light on the mysterious workings of the SARS-CoV-2 virus in the human body, an understanding that has remained elusive to medical professionals treating afflicted patients.
Understanding the Bradykinin Storm
In a bid to understand the varying severity of Covid-19 infections, researchers have identified the phenomenon of the ‘bradykinin storm’. It is believed that this could be key to understanding why the virus affects some individuals more severely than others. However, this phenomenon alone does not explain the rapid deterioration observed in some patients. For this, the cytokine storm comes into play.
The Bradykinin Hypothesis
The Bradykinin hypothesis revolves around the SARS-CoV-2 virus’ utilization of a human enzyme, ACE2, to infiltrate the host’s cells. ACE2 plays a crucial role in regulating blood pressure, opposing the effects of another enzyme – ACE. The presence of the virus causes a decline in ACE levels in the lungs, which subsequently triggers an increase in ACE2 levels. This chain reaction eventually escalates the levels of bradykinin, a compound associated with pain sensation and lowering blood pressure, resulting in a ‘bradykinin storm’.
Effects of Bradykinin Storm
Bradykinin storm induces the expansion, leakiness, and subsequent swelling of blood vessels. Concurrently, the levels of hyaluronic acid, a sugar molecule that binds water to collagen (a protein), also rise steeply. Hyaluronic acid’s ability to absorb 1,000 times its weight in water gives it the capacity to form a hydrogel.
The Impact of the Bradykinin Storm
The fluid leakage induced by the bradykinin storm, coupled with the overproduction of hyaluronic acid, creates a Jello-like substance in the lungs. This substance obstructs oxygen uptake and carbon dioxide output, seriously impacting those with severe Covid-19 cases. The rapid fluid accumulation even renders high-tech intensive care, such as ventilators, useless.
Significance and Implications
The understanding of this mechanism opens up potential avenues for therapeutic interventions that target the bradykinin pathway. This could help mitigate the severe effects of Covid-19.
Cytokine Storm Syndrome
Cytokine Storm Syndrome features an overproduction of immune cells and cytokines due to a disturbance in the biological process. It can occur as a result of an infection, autoimmune condition (like coeliac disease, where the body’s immune system mistakenly attacks healthy cells), or other diseases. Signs and symptoms generally include high fever, inflammation (redness and swelling), severe fatigue, and nausea. In the case of flu infections, a cytokine storm causes a surge of activated immune cells into the lungs. Instead of combating the antigen, this results in lung inflammation, fluid build-up, and eventually, respiratory distress.