A common risk factor for Alzheimer’s disease may expose carriers to severe COVID-19 virus, cerebral hemorrhage
Research at the University of Helsinki and Helsinki University Hospital suggests that the APOE4 allele may also increase cerebral haemorrhage associated with COVID-19 and is associated with long-term COVID-associated mental fatigue.
About a third of Finns carry the APOE4 allele, a genetic variant that predisposes to carriers Alzheimers disease disease. Globally, researchers have reported findings showing an association between APOE4 and COVID-19 in terms of increased susceptibility to both. SARS-CoV-2 infection and COVID-19 mortality. Now the research team of the University of Helsinki and Helsinki University Hospital (HUS) has investigated the link between the APOE4 allele and the severity of COVID-19 in the Finnish population.
The multidisciplinary team also examined microscopic brain changes in the body affected by COVID-19 and the association between symptoms of APOE4 and mental fatigue experienced six months after the onset of the disease.
New findings were published Acta Neuropathologica Communications diary.
“The common ε4 allele of the APOE gene appears to be associated with an increased serious risk of COVID-19 in the Finnish population. The importance of APOE4 in the Finnish population is emphasized, which may be due to its genetic homogeneity, says neuropathologist consultant Liisa Myllykangas from the University of Helsinki and HUS.
The APOE4 allele more than doubles the risk of severe COVID-19
The results showed that the risk of receiving the COVID-19 form requiring intensive care more than doubled in carriers of the APOE4 allele. In addition, the study found more microscopic bleeding in the brain as a result of severe COVID-19 in carriers of this allele compared to others.
According to Chief Physician Johanna Hästbacka, APOE4 may also affect the severity of certain long-term symptoms, especially in cases of COVID-19 requiring hospitalization.
“One such symptom in the study was mental fatigue, which was defined as the difficulty of directing and concentrating,” Hästbacka says.
More research is needed
Myllykangas points out that the number of COVID-19 patients in the data now studied was relatively small and the results should be considered as indicative at this stage.
“To ensure our findings, these phenomena need to be studied in larger datasets,” he points out.
An important question that is not addressed in the study is the link between COVID-19 and the onset of memory impairment in APOE4 carriers.
“To answer this question, long-term follow-up studies with patients recovering from COVID-19 are needed, as well as basic research focusing on the interaction of APOE4 and systemic inflammation with brain memory mechanisms. Our research team has already launched these follow-up studies at the University of Helsinki and HUS.
Reference: “APOE ε4 is associated with an increased risk of severe COVID-19, cerebral hemorrhage and post-COVID mental fatigue: Finnish biobank, autopsy and clinical research ”Samu N. Kurki, Jonas Kantonen, Karri Kaivola, Laura Hokkanen, Mikko I. Mäyränpää, Henri Puttonen , Juha Martola, Minna Pöyhönen, Mia Kero, Jarno Tuimala, Olli Carpén, Anu Kantele, Olli Vapalahti, Marjaana Tiainen, Pentti J. Tienari, Kai Kaila, Johanna Hästbacka and Liisa Myllykangas, 23.12.2021, Acta Neuropathologica Communications.
DOI: 10.1186 / s40478-021-01302-7
The study utilized the research material of the FinnGen project, which combines genomic data generated from biobank samples with health data compiled from national registers. The results are based on data from more than 46,000 people, more than 2,600 of whom were diagnosed with COVID-19. In addition, tissue samples from 21 dead individuals who had suffered from COVID-19 were examined for microscopic changes in the brain. To determine the symptoms of mental fatigue, the researchers used the RECOVID dataset, which divided patients into three groups based on the severity of the disease. The data also included a healthy control group. The RECOVID dataset contained a total of 156 subjects.