Immunosenescence is a therapeutic target for frailty in older adults: a narrative review.

Background and Objective: Aging refers to a progressive decrease in functional performance, leading to increased mortality risk. At present, life expectancy is increasing worldwide and is expected to exceed 80 years by 2040. However, this increase in life expectancy also indicates a rise in the incidence and prevalence of diseases, such as cardiovascular, neurological, musculoskeletal, and oncological diseases, which are associated with aging. The exact underlying mechanisms of aging remain unknown, and whether it is a programmed process or the consequence of an accumulation of stress events remains unclear. Thus, more scientific research is needed to improve the management of complex and frail patients. Methods: Several databases were searched with the following key words: immunosenescence, inflamm-aging, frailty, sarcopenia and skeletal muscle, etc. Key Content and Findings: Skeletal muscle is the core phenotype of frailty and sarcopenia. Immune aging and skeletal muscle decline interplay with each other and form a vicious circle. Maintaining muscle health is beneficial for immune function and delays the onset of frailty. Particularly, in the context of the ongoing corona virus disease (COVID)-19 pandemic, studies have shown that the elderly are more prone to the consequences of the SARS-CoV-2 virus. It has been reported that the rates of hospitalization in the 65-74, 75-84, and ≥85 years old group were 5×, 8×, and 10× greater than the 18-29 years old group, with corresponding COVID-19-related deaths being 60×, 140×, and 330× that of the younger reference group, respectively. Considering the above, this review aims to discuss the relationship between immunosenescence, skeletal muscle, and frailty, and to explore immunosenescence as a potential therapeutic target to prevent frailty and extend healthspan, with some emphasis on the effects of the COVID-19 pandemic on the elderly. Conclusions: Immunosenescence is a promising potential therapeutic target for frailty and is worthy of further investigation.

An immunologist's guide to immunosenescence and its treatment.

INTRODUCTION: Aging causes several changes in the immune system, although immune aging is strongly influenced by individual immunological history, as well as genetic and environmental factors leading to inter-individual variability. AREAS COVERED: We focused on the biological and clinical meaning of immunosenescence. SARS-CoV-2 and Yellow Fever vaccine have demonstrated the clinical relevance of immunosenescence, while inconsistent results, obtained from longitudinal studies aimed at looking for immune risk phenotypes, have revealed that immunosenescence is highly context-dependent. Large projects allowed the delineation of the drivers of immune system variance, including genetic and environmental factors, sex, smoking, and co-habitation. Therefore, it is difficult to identify the interventions that can be envisaged to maintain or improve immune function in older people. That suggests that drug treatment of immunosenescence should require personalized intervention. Regarding this, we discussed the role of changes in lifestyle as a potential therapeutic approach. EXPERT OPINION: Our review points out that age is only part of the problem of immunosenescence. Everyone ages differently because is unique in genetics and experience of life and this applies even more to the immune system (immunobiography). Finally, the review shows how appreciable results in the modification of immunosenescence biomarkers can be achieved with lifestyle modification.

Aging correlates with lower threshold cycle values for RdRP/RdRP+S genes during molecular detection of SARS-CoV-2.

RT-qPCR is the most reliable molecular method for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Here, we analyzed results of RT-qPCR obtained for 3044 patients diagnosed as SARS-CoV-2-positive using four different molecular tests utilizing five RNA sequences. The analysis showed that patients' age inversely correlates with threshold cycle (Ct) values for RdRP gene (LightMix® Modular Wuhan CoV RdRP-gene by Roche Diagnostics) and RdRP+S genes (MutaPLEX® Coronavirus RT-PCR kit by Immundiagnostic). At the same time, there was no correlation between age and Ct values for E, N, and ORF1ab genes. When patients were grouped by age, mean Ct values for RdRP gene in older patients were significantly lower compared with younger individuals. Collectively, our report indicates that older SARS-CoV-2-infected individuals exhibit higher viremia at diagnosis than younger patients, which may reflect impaired functioning of their immune response and predispose to more severe disease and worse prognosis.

The role of extracellular DNA in COVID-19: Clues from inflamm-aging.

Epidemiological data convey severe prognosis and high mortality rate for COVID-19 in elderly men affected by age-related diseases. These subjects develop local and systemic hyper-inflammation, which are associated with thrombotic complications and multi-organ failure. Therefore, understanding SARS-CoV-2 induced hyper-inflammation in elderly men is a pressing need. Here we focus on the role of extracellular DNA, mainly mitochondrial DNA (mtDNA) and telomeric DNA (telDNA) in the modulation of systemic inflammation in these subjects. In particular, extracellular mtDNA is regarded as a powerful trigger of the inflammatory response. On the contrary, extracellular telDNA pool is estimated to be capable of inhibiting a variety of inflammatory pathways. In turn, we underpin that telDNA reservoir is progressively depleted during aging, and that it is scarcer in men than in women. We propose that an increase in extracellular mtDNA, concomitant with the reduction of the anti-inflammatory telDNA reservoir may explain hyper-inflammation in elderly male affected by COVID-19. This scenario is reminiscent of inflamm-aging, the portmanteau word that depicts how aging and aging related diseases are intimately linked to inflammation.

Inflamm-aging: Why older men are the most susceptible to SARS-CoV-2 complicated outcomes.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is characterized by a high mortality of elderly men with age-related comorbidities. In most of these patients, uncontrolled local and systemic hyperinflammation induces severe and often lethal outcomes. The aging process is characterized by the gradual development of a chronic subclinical systemic inflammation (inflamm-aging) and by acquired immune system impairment (immune senescence). Here, we advance the hypothesis that four well-recognized features of aging contribute to the disproportionate SARS-CoV-2 mortality suffered by elderly men: i. the presence of subclinical systemic inflammation without overt disease, ii. a blunted acquired immune system and type I interferon response due to the chronic inflammation; iii. the downregulation of ACE2 (i.e. the SARS-CoV-2 receptor); and iv. accelerated biological aging. The high mortality rate of SARS-CoV-2 infection suggests that clarification of the mechanisms of inflamm-aging and immune senescence can help combat not only age-related disorders but also SARS-CoV-2 infection.