Currently, supportive therapy for COVID-19 in hospitals aims to keep oxygen levels sufficiently high with treatments such as supplementary oxygen or by using ventilators to artificially support the body’s breathing process. In normal circumstances, if the oxygen becomes too low in a part of the lung, the blood vessels in that part constrict to redirect the blood flow to other regions of the lung where the oxygen is higher. In COVID-19 patients, however, the Oxford University researchers hypothesise that this mechanism is not working properly. Consequently, the blood flow is going to the most diseased and non-functioning parts of the lung where the oxygen is low, and is not getting diverted to the healthier parts of the lung where the oxygen is higher. This means that too much blood flows through the lungs without picking up oxygen.
The Department of Physiology, Anatomy & Genetics (DPAG) led research team aims to address this problem by preferentially constricting the blood vessels going through the diseased parts of the lung, thereby redirecting the blood towards the healthy parts where it can pick up oxygen. To do this, they will use an old drug first developed in France called almitrine bismesylate, which is known in the scientific community to have this effect when treating acute respiratory distress syndrome (ARDS). The drug acts to increase the sensitivity of the acute oxygen sensing mechanisms of the body. According to Lead Researcher Professor Peter Robbins: “We know that almitrine can increase oxygen levels in patients with acute respiratory distress syndrome by constricting the blood vessels in regions of the lung where the oxygen is low. We want to see if almitrine will also have this effect in COVID-19 patients.”