A collaboration between researchers at Trinity College Dublin and FutureNeuro has led to a groundbreaking revelation that sheds light on the phenomenon of brain fog and cognitive impairment observed in some Long COVID patients.
Following the outbreak of the novel coronavirus SARS-CoV-2 towards the end of 2019, a condition known as Long COVID emerged as a persistent consequence of the initial infection. Characterized by a wide range of up to 200 symptoms, Long COVID predominantly leaves patients battling ongoing fatigue, breathing difficulties, memory and concentration issues, along with muscle and joint pain. Although most of those affected by COVID-19 recover entirely, the persistence of these symptoms beyond 12 weeks after infection is classified as Long COVID.
Having evolved into a significant public health concern since the pandemic’s onset in 2020, Long COVID is believed to impact as much as 10% of individuals infected by the SARS-CoV-2 virus. Notably, almost half of the individuals experiencing Long COVID report enduring neurological symptoms such as cognitive decline, fatigue, and brain fog.
A study conducted by the team at Trinity and published in the esteemed journal Nature Neuroscience revealed a disruption in the blood vessels within the brains of Long COVID sufferers experiencing brain fog. This discovery of vascular “leakiness” provides a clear distinction between those with cognitive decline and those without, despite both groups suffering from Long COVID.
The research spearheaded by experts at Trinity’s Smurfit Institute of Genetics, School of Genetics and Microbiology, and School of Medicine has also introduced an innovative MRI scanning technique. This method reveals the impact of Long COVID on the intricate network of blood vessels within the brain.
Professor Matthew Campbell, a leading figure in Genetics at Trinity and Principal Investigator at FutureNeuro, emphasized the significance of these findings. He stated that identifying leaky brain blood vessels in combination with an overactive immune response as central to brain fog in Long COVID is a critical step forward. This understanding paves the way for developing specific treatments tailored to these conditions.
This research was initiated through a rapid response grant from Science Foundation Ireland (SFI) during the peak of the pandemic in 2020 and involved recruiting Long COVID patients as well as those hospitalized at St James’ Hospital.
Professor Colin Doherty, Professor of Neurology at Trinity and Principal Investigator at FutureNeuro, lauded the effort and expertise of medical staff and trainees in conducting this complex study under the pressures of a national crisis. He highlighted that these findings are set to revolutionize our approach to treating post-viral neurological conditions and underscore that the neurological manifestations of Long COVID can be objectively measured, revealing significant metabolic and vascular changes in the brain.
As we move forward from COVID-19, it has become increasingly clear that many neurological conditions, such as Multiple Sclerosis (MS), may be triggered by viral infections. However, establishing a direct link has historically been difficult.
Professor Campbell further noted that the Trinity team confirmed that every Long COVID patient had been previously diagnosed with a SARS-CoV-2 infection, thanks to Ireland’s stringent PCR-based diagnostic requirements. This revelation that viral infections leading to post-viral syndromes could cause blood vessel leakage in the brain represents a potentially revolutionary development currently under active investigation by the team.
Dr. Chris Greene, a Postdoctoral research fellow and the study’s first author, stated that these findings lay the groundwork for further research into the molecular processes behind post-viral fatigue and brain fog. He suggested that similar mechanisms likely operate across various viral infections, bringing us closer to understanding the causes of neurological dysfunction in affected patients.
More information: Chris Greene et al, Blood–brain barrier disruption and sustained systemic inflammation in individuals with long COVID-associated cognitive impairment, Nature Neuroscience. DOI: 10.1038/s41593-024-01576-9
Journal information: Nature Neuroscience Provided by Trinity College Dublin
