COVID-19 and Alzheimer's Disease: Neuroinflammation, Oxidative Stress, Ferroptosis, and Mechanisms Involved

Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by marked cognitive decline, memory loss, and spatio-temporal troubles and, in severe cases, lack of recognition of family members. Neurological symptoms, cognitive disturbances, and the inflammatory frame due to COVID-19, together with long-term effects, have fueled renewed interest in AD based on similar damage. COVID-19 also caused the acceleration of AD symptom onset. In this regard, the morbidity and mortality of COVID-19 were reported to be increased in patients with AD due to multiple pathological changes such as excessive expression of the viral receptor angiotensin-converting enzyme 2 (ACE2), comorbidities such as diabetes, hypertension, or drug-drug interactions in patients receiving polypharmacy and the high presence of proinflammatory molecules. Furthermore, the release of cytokines, neuroinflammation, oxidative stress, and ferroptosis in both diseases showed common underlying mechanisms, which together worsen the clinical picture and prognosis of these patients.