A team of scientists from Trinity College Dublin and researchers from FutureNeuro have announced a major discovery that has profound implications for our understanding of brain fog and cognitive decline in some Long-COVID patients. In the months following the emergence of the novel coronavirus SARS-CoV2 in late 2019, a patient-reported syndrome termed "Long-COVID" began to emerge as a persistent manifestation of acute infection.

As many as 200 symptoms have been reported for Long-COVID so far, but generally patients report persistent symptoms such as fatigue, shortness of breath, memory and thinking problems, and joint/muscle pain. While the vast majority of people infected with COVID-19 fully recover, any of these symptoms that persist for more than 12 weeks after infection can be considered Long-COVID.

Since the outbreak of the pandemic in 2020, Long-COVID has now become a major public health issue. Although incidence rates vary internationally, it is estimated that the incidence of Long-COVID is as high as 10% among patients infected with the SARS-CoV2 virus. Less than 50% of these Long-COVID patients reported some form of lingering neurological effects, such as cognitive decline, fatigue and brain fog.

Groundbreaking discoveries in neuroscience

Now, findings reported by a Trinity College research team in the top international journal Nature Neuroscience suggest that the integrity of blood vessels in the brain is compromised in patients with Long-COVID and brain fog. This blood vessel "leakage" can objectively differentiate between patients with brain fog and cognitive decline and those with Long-COVID but no brain fog.

The research team, led by scientists from the Smurfit Institute of Genetics in Trinity's School of Genetics and Microbiology and neuroscientists from the School of Medicine, also discovered a new MRI scan that shows how Long-COVID affects the delicate network of blood vessels in the human brain.

"We have shown for the first time that leaky blood vessels in the human brain and an overactive immune system may be the main causes of brain fog associated with Long-COVID. This is important because understanding the underlying causes of these diseases will enable us to develop targeted treatments for patients in the future," said Professor Matthew Campbell, Professor of Genetics and Head of the Department of Genetics at Trinity College and principal investigator of FutureNeuro.

The project, initiated through a Rapid Response Fund funded by Science Foundation Ireland (SFI) at the height of the pandemic in 2020, involves recruiting patients with long-term COVID-19 impacts as well as those hospitalized at St James's Hospital.

"Conducting this complex clinical study at a time when the country is facing a crisis and the hospital system is under tremendous pressure is a testament to the skills and resources of our medical trainees and staff. The results are now likely to change the way we understand and treat post-viral neurological disease. It also confirms that the neurological symptoms of Long-COVID are measurable and that metabolic and vascular changes in the brain are real and evident," said Professor Colin Doherty, Professor of Neurology and Dean of the School of Medicine at Trinity College and Principal Investigator of FutureNeuro.

Beyond COVID-19

In recent years, many neurological diseases, such as multiple sclerosis (MS), are likely to be triggered by viral infections. However, proving this direct link has been difficult.

Professor Campbell added: "Here, the Trinity research team was able to demonstrate that every patient who developed Long-COVID was diagnosed as being infected with SARS-CoV2, as Ireland requires that every recorded case be diagnosed using more precise PCR-based methods. Many other viral infections that cause post-viral syndrome may cause leakage in the brain blood vessels, a concept that may change treatment principles and is being actively investigated by the research team."

Compiled source: ScitechDaily