Researchers at the University of Malta have found a possible reason for the ongoing and often debilitating symptoms experienced by long COVID-19 patients. In their new study, published in the scientific journal BBA Molecular Basis of Disease, they discuss the potential implications for developing medications that could help treat patients who haven’t fully recovered from COVID-19.
After recovering from COVID-19, nearly one-third of individuals experience symptoms that can significantly disrupt their lives. These symptoms may include persistent fatigue, difficulty breathing, trouble concentrating (often referred to as “brain fog”), and muscle weakness. Despite the growing impact of long COVID on daily life, the cause has remained unclear.
The coronavirus responsible for COVID-19, SARS-CoV-2, attaches to the ACE2 (angiotensin-converting enzyme 2) receptor, which serves as the doorway through which the virus infects cells. In a groundbreaking study, University of Malta researchers used fruit flies to reduce the levels of the ACE2 receptor. Even without the virus present, this reduction was enough to cause fatigue and decreased mobility.
“Our research clearly shows that depletion of ACE2 is central to the neuromuscular complications experienced by a significant percentage of COVID-19 patients”, said Professor Ruben Cauchi, who heads the Motor Neuron Disease Laboratory at the University of Malta.
The findings are from a study conducted during the pandemic. Prof. Cauchi and his team used fruit flies to research ALS, as they have genetic and biological similarities to humans.
The Maltese scientists found that when ACE2 levels were downregulated, there was a breakdown in communication between nerves and muscles. This resulted in several key molecules being compromised, which are necessary for nerves to send messages to muscles.
ACE2 levels can be reduced or its function dampened in humans after coronavirus infection. This can happen through various paths, including being hijacked by the virus or being targeted by autoantibodies, which can cause the immune system to attack the body, as in Multiple Sclerosis. Dr. Paul Herrera performed the experiments essential to the study. There have also been reports of virus persistence long after the initial infection.
The discovery by the University of Malta sheds light on the lasting impact of COVID-19 infection and paves the way for therapeutic approaches to mitigate chronically disabling complications.