COVID-19: A Challenge to Physiology of Aging

Abstract

The death toll of the current COVID-19 pandemic is strongly biased toward the elderly. COVID-19 case fatality rate (CFR) increases with age exponentially, its doubling time being about 7 years, irrespective of countries and epidemic stages. The same age-dependent mortality pattern known as the Gompertz law is featured by the total mortality and its main constituents attributed to cardiovascular, metabolic, neurological, and oncological diseases. Among patients dying of COVID-19, most have at least one of these conditions, whereas none is found in most of those who pass it successfully. Thus, gerontology is indispensable in dealing with the pandemic, which becomes a benchmark for validating the gerontological concepts and advances. The two basic alternative gerontological concepts imply that either aging results from the accumulation of stochastic damage, or is programmed. Based on these different grounds, several putative anti-aging drugs have been proposed as adjuvant means for COVID-19 prevention and/or treatment. These proposals are reviewed in the context of attributing the molecular targets of these drugs to the signaling pathways between the sensors of resource availability and the molecular mechanisms that allocate resources to storage, growth and reproduction or to self-maintenance and repair. Each of the drugs appears to reproduce only a part of the physiological responses to reduced resource availability caused by either dietary calories restriction or physical activity promotion, which are the most robust means of mitigating the adverse manifestations of aging. In the pathophysiological terms, the conditions of the endothelium, which worsen as age increases and may be significantly improved by the physical activity, is a common limiting factor for the abilities to withstand both physical stresses and challenges imposed by COVID-19. However, the current anti-epidemic measures promote sedentary indoor lifestyles, at odds with the most efficient behavioral interventions known to decrease the vulnerability to both the severe forms of COVID-19 and the prevalent aging-associated diseases. To achieve a proper balance in public health approaches to COVID-19, gerontologists should be involved in crosstalk between virologists, therapists, epidemiologists, and policy makers. The present publication suggests a conceptual background for that.

COVID-19 Vaccines: Current Conditions and Future Prospects

“…Most vaccines focus on the antibody response, and T cell responses are largely neglected. Although it is currently difficult to determine the exact antibody levels and duration after infection, evidence suggests that individuals who have recovered from COVID-19 have developed a favorable immune response regarding their memory CD4+ and CD8+ T cells [20]. In some patients, memory CD4+ and CD8+ T cells have generated responses for numerous COVID-19 proteins, such as the nucleoprotein and spike proteins [20].…”

“…Although it is currently difficult to determine the exact antibody levels and duration after infection, evidence suggests that individuals who have recovered from COVID-19 have developed a favorable immune response regarding their memory CD4+ and CD8+ T cells [20]. In some patients, memory CD4+ and CD8+ T cells have generated responses for numerous COVID-19 proteins, such as the nucleoprotein and spike proteins [20]. Although the antibodies to the nucleoprotein are improbable to neutralize COVID-19, there have been cases in which they have produced satisfactory protection, such as with the mouse hepatitis virus (MHV), which is also a coronavirus [43,44].…”

“…When examining the immune response generated by CD8+ T cells, it is inconclusive whether T cell hypoactivation or hyperactivation occurs [20]. In general, CD8+ hyperactivation manifests with elevated cytotoxicity and NKC-related markers, while hypoactivation displays as the opposite [20].…”

“…The virus also primarily manifests as a lower respiratory tract disease, which leads to respiratory distress. Individuals with preexisting health conditions-obesity, cardiomyopathies, and diabetes-have reported a higher risk of experiencing severe COVID-19 symptoms due to potentially impaired immune systems [20][21][22]. The most common clinical manifestations for this disease include shortness of breath, fever, cough, and fatigue while the less common symptoms include headache, vomiting, and dizziness [23].…”

An essay on the nominal vs. real definitions of aging

“…Moreover, any such drug can target only a part of molecular interactions actuated by the two physiological intervention. Mimetics can only mimic, that is they cannot reproduce fully the mimicked interventions and thus cannot perform better than the latter can (Golubev 2018b , 2020 ; Rattan 2020 ).…”