A public health perspective of aging: do hyper-inflammatory syndromes such as COVID-19, SARS, ARDS, cytokine storm syndrome, and post-ICU syndrome accelerate short- and long-term inflammaging?

Inflammation and aging-related disease: A transdisciplinary inflammaging framework

Inflammaging, a state of chronic, progressive low-grade inflammation during aging, is associated with several adverse clinical outcomes, including frailty, disability, and death. Chronic inflammation is a hallmark of aging and is linked to the pathogenesis of many aging-related diseases. Anti-inflammatory therapies are also increasingly being studied as potential anti-aging treatments, and clinical trials have shown benefits in selected aging-related diseases. Despite promising advances, significant gaps remain in defining, measuring, treating, and integrating inflammaging into clinical geroscience research. The Clin-STAR Inflammation Research Interest Group was formed by a group of transdisciplinary clinician-scientists with the goal of advancing inflammaging-related clinical research and improving patient-centered care for older adults. Here, we integrate insights from nine medical subspecialties to illustrate the widespread impact of inflammaging on diseases linked to aging, highlighting the extensive opportunities for targeted interventions. We then propose a transdisciplinary approach to enhance understanding and treatment of inflammaging that aims to improve comprehensive care for our aging patients.

Prevalence and Risk Factors of Multitype Post-COVID Pain in a Cohort of Previously Hospitalized COVID-19 Survivors: A Danish Cross-Sectional Survey

This population-based study investigated the prevalence of de novo, multitype, post-coronavirus disease (COVID) pain and its associated risk factors in previously hospitalized coronavirus disease 2019 (COVID-19) survivors. The nationwide, cross-sectional study included a cohort of Danish residents previously hospitalized due to severe acute respiratory syndrome coronavirus-2 infection between March 2020 and December 2021. Demographic data, preexisting medical comorbidities, previous pain-related symptoms, medication use for pain management, pain intensity (4-point scale), and development of de novo, multitype, post-COVID pain were collected by a self-reported survey distributed via e-Boks (a secured national digital mail system used in Denmark to provide public information to residents). The sample comprised 4,712 previously hospitalized COVID-19 survivors (48.6% women, mean age: 60.1 ± 15.6 years). At the time of the study (21 ± 6 months after hospitalization), 18.0% (847) reported the presence of de novo, multitype, post-COVID pain, and 38.6% of any pain. A multivariate analysis revealed that female sex (Odds Ratio (OR) 1.711, 95% Confidence Interval (CI) 1.444-2.023), higher body mass index (OR 1.032, 95% CI 1.019-1.045), intensive care unit admission (OR 1.597, 95% CI 1.324-1.926), previous history of whiplash (OR 2.471, 95% CI 1.004-6.081), anxiety (OR 3.626, 95% CI 1.335-9.708), and younger age (OR .982, 95% CI .976-.987) were factors associated with development of de novo, multitype, post-COVID pain. High income (OR .635, 95% CI .494-.817) and high educational level (OR .774, 95% CI .609-.984) were protective factors. In conclusion, multitype pain as a de novo post-COVID symptom was present in 18.0% of previously hospitalized COVID-19 survivors more than 1 year after hospital discharge and as such can be considered as adding to the global burden of chronic pain. PERSPECTIVE: The study investigates the prevalence of de novo, multitype, post-COVID pain in previously hospitalized COVID-19 survivors. This article presents potential risk factors associated with developing new pain symptoms. The results will contribute to understanding the possibility of predicting postinfectious pain from COVID-19 for future analysis.

Aging and Inflammation

Aging can be conceptualized as the progressive disequilibrium between stochastic damage accumulation and resilience mechanisms that continuously repair that damage, which eventually cause the development of chronic disease, frailty, and death. The immune system is at the forefront of these resilience mechanisms. Indeed, aging is associated with persistent activation of the immune system, witnessed by a high circulating level of inflammatory markers and activation of immune cells in the circulation and in tissue, a condition called "inflammaging." Like aging, inflammaging is associated with increased risk of many age-related pathologies and disabilities, as well as frailty and death. Herein we discuss recent advances in the understanding of the mechanisms leading to inflammaging and the intrinsic dysregulation of the immune function that occurs with aging. We focus on the underlying mechanisms of chronic inflammation, in particular the role of NF-κB and recent studies targeting proinflammatory mediators. We further explore the dysregulation of the immune response with age and immunosenescence as an important mechanistic immune response to acute stressors. We examine the role of the gastrointestinal microbiome, age-related dysbiosis, and the integrated stress response in modulating the inflammatory "response" to damage accumulation and stress. We conclude by focusing on the seminal question of whether reducing inflammation is useful and the results of related clinical trials. In summary, we propose that inflammation may be viewed both as a clinical biomarker of the failure of resilience mechanisms and as a causal factor in the rising burden of disease and disabilities with aging. The fact that inflammation can be reduced through nonpharmacological interventions such as diet and exercise suggests that a life course approach based on education may be a successful strategy to increase the health span with few adverse consequences.

Berberine attenuates brain aging via stabilizing redox homeostasis and inflammation in an accelerated senescence model of Wistar rats

Aging is a multifaceted and progressive physiological change of the organism categorized by the accumulation of deteriorating processes, which ultimately compromise the biological functions. The objective of this study was to investigate the anti-aging potential of berberine (BBR) in D-galactose (D-Gal) induced aging in rat models. In this study, male Wistar rats were divided into four groups: The control group was given only vehicle, the BBR group was treated with berberine orally, the D-Gal group was treated with D-galactose subcutaneously and the BBR + D-Gal group was treated with D-galactose and berberine simultaneously. D-galactose exposure elevated the pro-oxidants such as malondialdehyde (MDA) level, protein carbonyl and advanced oxidation protein products (AOPP) in the brain. It decreased the anti-oxidants such as reduced glutathione (GSH) and ferric reducing antioxidant potential (FRAP) in the brain. D-galactose treatment also reduced the mitochondrial complexes (I, II, III and IV) activities and elevated the inflammatory markers such as interleukine-6 (IL-6), tumor necrosis factor- α (TNF-α) and C-reactive protein (CRP). The mRNA expressions of IL-6 and TNF-α in the brain were upregulated following D-galactose exposure. Berberine co-treatment in D-galactose induced aging rat model prevented the alteration of pro-oxidant and anti-oxidant in the brain. Berberine treatment restored the mitochondrial complex activities in the brain and also normalized the inflammatory markers. Based on these findings we conclude that berberine treatment has the potential to mitigate brain aging in rats via stabilizing the redox equilibrium and neuroinflammation.

Unraveling Links between Chronic Inflammation and Long COVID: Workshop Report

As COVID-19 continues, an increasing number of patients develop long COVID symptoms varying in severity that last for weeks, months, or longer. Symptoms commonly include lingering loss of smell and taste, hearing loss, extreme fatigue, and "brain fog." Still, persistent cardiovascular and respiratory problems, muscle weakness, and neurologic issues have also been documented. A major problem is the lack of clear guidelines for diagnosing long COVID. Although some studies suggest that long COVID is due to prolonged inflammation after SARS-CoV-2 infection, the underlying mechanisms remain unclear. The broad range of COVID-19's bodily effects and responses after initial viral infection are also poorly understood. This workshop brought together multidisciplinary experts to showcase and discuss the latest research on long COVID and chronic inflammation that might be associated with the persistent sequelae following COVID-19 infection.

Potential Impact of Long COVID-19 on Orthodontic Treatment

Pooled estimates indicate about 226 million individuals are currently experiencing or have experienced persistent symptoms from COVID-19. Long COVID-19 (LC) has been associated with a prolonged inflammatory and stress responses in affected individuals. Due to common pathways, LC could impact the biological mechanisms of orthodontic tooth movement, orthodontically-induced inflammatory root resorption and periodontal tissue response of patients undergoing orthodontic treatment. The authors of the present report discussed potential biological mechanisms through which LC may influence orthodontic treatment highlighting the need for further research in this area.

Tuberculosis and COVID-19 in the elderly: factors driving a higher burden of disease

Mycobacterium tuberculosis (M.tb) and SARS-CoV-2 are both infections that can lead to severe disease in the lower lung. However, these two infections are caused by very different pathogens (Mycobacterium vs. virus), they have different mechanisms of pathogenesis and immune response, and differ in how long the infection lasts. Despite the differences, SARS-CoV-2 and M.tb share a common feature, which is also frequently observed in other respiratory infections: the burden of disease in the elderly is greater. Here, we discuss possible reasons for the higher burden in older adults, including the effect of co-morbidities, deterioration of the lung environment, auto-immunity, and a reduced antibody response. While the answer is likely to be multifactorial, understanding the main drivers across different infections may allow us to design broader interventions that increase the health-span of older people.

Frailty after COVID-19: The wave after?

The COVID-19 pandemic poses an ongoing public health challenge, with a focus on older adults. Given the large number of older persons who have recovered from COVID-19 and reports of long-lasting sequelae, there is reasonable concern that the COVID-19 pandemic may lead to a long-term deterioration in the health of older adults, i.e., a potential "wave of frailty." Therefore, it is critical to better understand the circumstances surrounding the development of frailty as a result of COVID-19, as well as the underlying mechanisms and factors contributing to this development. We conducted a narrative review of the most relevant articles published on the association between COVID-19 and frailty through January 2023. Although few studies to date have addressed the effects of COVID-19 on the onset and progression of frailty, the available data suggest that there is indeed an increase in frailty in the elderly as a result of COVID-19. Regarding the underlying mechanisms, a multicausal genesis can be assumed, involving both direct viral effects and indirect effects, particularly from the imposed lockdowns with devastating consequences for the elderly: decreased physical activity, altered diet, sarcopenia, fatigue, social isolation, neurological problems, inflammation, and cardiovascular morbidity are among the possible mediators. Since the COVID-19 pandemic is leading to an increase in frailty in the elderly, there is an urgent need to raise awareness of this still little-known problem of potentially great public health importance and to find appropriate prevention and treatment measures.

Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Postacute Sequelae of SARS-CoV-2: More in Common Than Not?

TOPIC IMPORTANCE

Postacute sequelae of SARS-CoV-2 (PASC) is a long-term consequence of acute infection from COVID-19. Clinical overlap between PASC and myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) has been observed, with shared symptoms including intractable fatigue, postexertional malaise, and orthostatic intolerance. The mechanistic underpinnings of such symptoms are poorly understood.

REVIEW FINDINGS

Early studies suggest deconditioning as the primary explanation for exertional intolerance in PASC. Cardiopulmonary exercise testing reveals perturbations related to systemic blood flow and ventilatory control associated with acute exercise intolerance in PASC, which are not typical of simple detraining. Hemodynamic and gas exchange derangements in PASC have substantial overlap with those observed with ME/CFS, suggestive of shared mechanisms.

SUMMARY

This review illustrates exercise pathophysiologic commonalities between PASC and ME/CFS that will help guide future diagnostics and treatment.

Development of nanozymes for promising alleviation of COVID-19-associated arthritis

The COVID-19 pandemic caused by SARS-CoV-2 has been identified as a culprit in the development of a variety of disorders, including arthritis. Although the emergence of arthritis following SARS-CoV-2 infection may not be immediately discernible, its underlying pathogenesis is likely to involve a complex interplay of infections, oxidative stress, immune responses, abnormal production of inflammatory factors, cellular destruction, etc. Fortunately, recent advancements in nanozymes with enzyme-like activities have shown potent antiviral effects and the ability to inhibit oxidative stress and cytokines and provide immunotherapeutic effects while also safeguarding diverse cell populations. These adaptable nanozymes have already exhibited efficacy in treating common types of arthritis, and their distinctive synergistic therapeutic effects offer great potential in the fight against arthritis associated with COVID-19. In this comprehensive review, we explore the potential of nanozymes in alleviating arthritis following SARS-CoV-2 infection by neutralizing the underlying factors associated with the disease. We also provide a detailed analysis of the common therapeutic pathways employed by these nanozymes and offer insights into how they can be further optimized to effectively address COVID-19-associated arthritis.

[S1 guidelines for the management of postviral conditions using the example of post-COVID-19]

These S1 guidelines are an updated and expanded version of the S1 guidelines on long COVID differential diagnostic and management strategies. They summarize the state of knowledge on postviral conditions like long/post COVID at the time of writing. Due to the dynamic nature of knowledge development, they are intended to be "living guidelines". The focus is on practical applicability at the level of primary care, which is understood to be the appropriate place for initial access and for primary care and treatment. The guidelines provide recommendations on the course of treatment, differential diagnostics of the most common symptoms that can result from infections like with SARS-CoV-2, treatment options, patient management and care, reintegration and rehabilitation. The guidelines have been developed through an interdisciplinary and interprofessional process and provide recommendations on interfaces and possibilities for collaboration.

Impact of aging on immunity in the context of COVID-19, HIV, and tuberculosis

Knowledge of aging biology needs to be expanded due to the continuously growing number of elderly people worldwide. Aging induces changes that affect all systems of the body. The risk of cardiovascular disease and cancer increases with age. In particular, the age-induced adaptation of the immune system causes a greater susceptibility to infections and contributes to the inability to control pathogen growth and immune-mediated tissue damage. Since the impact of aging on immune function, is still to be fully elucidated, this review addresses some of the recent understanding of age-related changes affecting key components of immunity. The emphasis is on immunosenescence and inflammaging that are impacted by common infectious diseases that are characterized by a high mortality, and includes COVID-19, HIV and tuberculosis.

Immunology of Aging: the Birth of Inflammaging

The inflammaging concept was introduced in 2000 by Prof. Franceschi. This was an evolutionary or rather a revolutionary conceptualization of the immune changes in response to a lifelong stress. This conceptualization permitted to consider the lifelong proinflammatory process as an adaptation which could eventually lead to either beneficial or detrimental consequences. This dichotomy is influenced by both the genetics and the environment. Depending on which way prevails in an individual, the outcome may be healthy longevity or pathological aging burdened with aging-related diseases. The concept of inflammaging has also revealed the complex, systemic nature of aging. Thus, this conceptualization opens the way to consider age-related processes in their complexity, meaning that not only the process but also all counter-processes should be considered. It has also opened the way to add new concepts to the original one, leading to better understanding of the nature of inflammaging and of aging itself. Finally, it showed the way towards potential multimodal interventions involving a holistic approach to optimize the aging process towards a healthy longevity.

COVID-19 and cellular senescence

The clinical severity of coronavirus disease 2019 (COVID-19) is largely determined by host factors. Recent advances point to cellular senescence, an ageing-related switch in cellular state, as a critical regulator of SARS-CoV-2-evoked hyperinflammation. SARS-CoV-2, like other viruses, can induce senescence and exacerbates the senescence-associated secretory phenotype (SASP), which is comprised largely of pro-inflammatory, extracellular matrix-degrading, complement-activating and pro-coagulatory factors secreted by senescent cells. These effects are enhanced in elderly individuals who have an increased proportion of pre-existing senescent cells in their tissues. SASP factors can contribute to a 'cytokine storm', tissue-destructive immune cell infiltration, endothelialitis (endotheliitis), fibrosis and microthrombosis. SASP-driven spreading of cellular senescence uncouples tissue injury from direct SARS-CoV-2-inflicted cellular damage in a paracrine fashion and can further amplify the SASP by increasing the burden of senescent cells. Preclinical and early clinical studies indicate that targeted elimination of senescent cells may offer a novel therapeutic opportunity to attenuate clinical deterioration in COVID-19 and improve resilience following infection with SARS-CoV-2 or other pathogens.

Long COVID in the context of social determinants of health

The COVID-19 pandemic has been a challenge for the public health system and has highlighted health disparities. COVID-19 vaccines have effectively protected against infection and severe disease, but some patients continue to suffer from symptoms after their condition is resolved. These post-acute sequelae, or long COVID, continues to disproportionately affect some patients based on their social determinants of health (SDOH). This paper uses the World Health Organization's (WHO) SDOH conceptual framework to explore how SDOH influences long COVID outcomes.

Long COVID-19 Syndrome Severity According to Sex, Time from the Onset of the Disease, and Exercise Capacity-The Results of a Cross-Sectional Study

Symptoms of long COVID-19 syndrome (long COVID-19) are reported by 80% of convalescents up to several months after contracting the coronavirus-19 disease (COVID-19). The study aimed to assess the frequency and correlations of long COVID symptoms with sex, disease severity, time since the onset of the disease, and exercise capacity in a population of Polish convalescents hospitalized as a part of a rehabilitation program after COVID-19. The retrospective analysis was carried out based on medical records concerning reported symptoms, comorbidities, exercise capacity, fatigue and dyspnea on Borg's scale, arterial oxygen saturation (SpO₂), spirometric parameters, chest X-rays/computed tomography scans, systolic pulmonary artery pressure, and left ventricular ejection fraction. The study involved 471 patients aged 63.83 ± 9.93 years who had been hospitalized 191.32 ± 75.69 days from the onset of COVID-19, of which 269 (57.1%) were women. The most common symptoms were fatigue (99.57%), dyspnea (99.36%), and myalgia (97.03%). Women reported more symptoms than men (p < 0.001) and rated their fatigue as more severe (p = 0.021). Patients with depressed moods reported more physical symptoms than others (p < 0.001). Most long COVID symptoms, including dyspnea, fatigue, and depressive symptoms, were found with the same frequency in patients 12-24 weeks and >24 weeks after recovery (p = 0.874, p = 0.400, and p = 0.320, respectively), regardless of acute COVID-19 severity (p = 0.240, p = 0.826, and p = 0.108, respectively). Dyspnea severity correlated with forced vital capacity (FVC) (r = -0.153, p = 0.005), and forced expiratory volume in one second (FEV1) (r = -0.142, p = 0.008). Fatigue severity correlated with impaired FVC and FEV1 (both r = -0.162, p = 0.003). Fatigue and dyspnea inversely correlated with the distance in a six-minute walk test (r = -0.497, p < 0.001, and r = -0.327, p < 0.001). In conclusion, in our cohort, long COVID symptoms are more common in women. Dyspnea/fatigue and depressive symptoms do not tend to subside after an average six-month recovery period. The intensity of perceived fatigue may be exaggerated by the coexistence of neuropsychiatric disorders. Increased fatigue and dyspnea correlate with impaired spirometric parameters and significantly affects convalescents' exercise capacity.

A multidimensional approach to older patients during COVID-19 pandemic: a position paper of the Special Interest Group on Comprehensive Geriatric Assessment of the European Geriatric Medicine Society (EuGMS)

PURPOSE

The COVID-19 pandemic has been a dramatic trigger that has challenged the intrinsic capacity of older adults and of society. Due to the consequences for the older population worldwide, the Special Interest Group on Comprehensive Geriatric Assessment (CGA) of the European Geriatric Medicine Society (EuGMS) took the initiative of collecting evidence on the usefulness of the CGA-based multidimensional approach to older people during the COVID-19 pandemic.

METHODS

A narrative review of the most relevant articles published between January 2020 and November 2022 that focused on the multidimensional assessment of older adults during the COVID-19 pandemic.

RESULTS

Current evidence supports the critical role of the multidimensional approach to identify older adults hospitalized with COVID-19 at higher risk of longer hospitalization, functional decline, and short-term mortality. This approach appears to also be pivotal for the adequate stratification and management of the post-COVID condition as well as for the adoption of preventive measures (e.g., vaccinations, healthy lifestyle) among non-infected individuals.

CONCLUSION

Collecting information on multiple health domains (e.g., functional, cognitive, nutritional, social status, mobility, comorbidities, and polypharmacy) provides a better understanding of the intrinsic capacities and resilience of older adults affected by SARS-CoV-2 infection. The EuGMS SIG on CGA endorses the adoption of the multidimensional approach to guide the clinical management of older adults during the COVID-19 pandemic.

Post-COVID-19 syndrome: Insights into a novel post-infectious systemic disorder

Coronavirus disease 2019 (COVID-19) is currently considered a complex systemic infectious and inflammatory disease, determined by the infection with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), and the cause of one of the most important epidemiological phenomena in the last century - the COVID-19 pandemic. This infectious-inflammatory disease may generate a wide range of clinical manifestations and biological modifications, explained by the ubiquitous nature of the SARS-CoV-2 receptors, represented by the angiotensin-converting enzyme-2 (ACE-2), and by the host's violent immune and proinflammatory reaction to the viral infection. These manifestations include immunological disturbances, which, according to certain clinical findings, may persist post-infection, in the form of a presumed systemic inflammatory entity, defined by several clinical concepts with a common pathological significance: post-COVID-19 multisystem (or systemic) inflammatory syndrome, post-COVID syndrome or long-COVID. Although the pathophysiological mechanisms of the post-COVID-19 syndrome are elusive at the present moment, there are currently several studies that describe a systemic inflammatory or autoimmune phenomenon following the remission of the COVID-19 infection in some patients, which suggests the existence of molecular and cellular immune abnormalities, most probably due to the host's initial violent immune response to the viral infection, in the form of three overlapping entities: secondary hemophagocytic lymph histiocytosis (HLH), macrophage activation syndrome (MAS) and cytokine release syndrome (CRS). Thus, this is reminiscent of different classic autoimmune diseases, in which various infections are risk factors in developing the autoimmune process.

Role of Sex and Age in Fatal Outcomes of COVID-19: Women and Older Centenarians Are More Resilient

In the present paper, we have analysed the role of age and sex in the fatal outcome of COVID-19, as there are conflicting results in the literature. As such, we have answered three controversial questions regarding this aspect of the COVID-19 pandemic: (1) Have women been more resilient than men? (2) Did centenarians die less than the remaining older people? (3) Were older centenarians more resistant to SARS-CoV-2 than younger centenarians? The literature review demonstrated that: (1) it is women who are more resilient, in agreement with data showing that women live longer than men even during severe famines and epidemics; however, there are conflicting data regarding centenarian men; (2) centenarians overall did not die less than remaining older people, likely linked to their frailty; (3) in the first pandemic wave of 2020, centenarians > 101 years old (i.e., born before 1919), but not "younger centenarians", have been more resilient to COVID-19 and this may be related to the 1918 Spanish flu epidemic, although it is unclear what the mechanisms might be involved.

Cardiovascular and autonomic dysfunction in long-COVID syndrome and the potential role of non-invasive therapeutic strategies on cardiovascular outcomes

A significant percentage of COVID-19 survivors develop long-lasting cardiovascular sequelae linked to autonomic nervous system dysfunction, including fatigue, arrhythmias, and hypertension. This post-COVID-19 cardiovascular syndrome is one facet of "long-COVID," generally defined as long-term health problems persisting/appearing after the typical recovery period of COVID-19. Despite the fact that this syndrome is not fully understood, it is urgent to develop strategies for diagnosing/managing long-COVID due to the immense potential for future disease burden. New diagnostic/therapeutic tools should provide health personnel with the ability to manage the consequences of long-COVID and preserve/improve patient quality of life. It has been shown that cardiovascular rehabilitation programs (CRPs) stimulate the parasympathetic nervous system, improve cardiorespiratory fitness (CRF), and reduce cardiovascular risk factors, hospitalization rates, and cognitive impairment in patients suffering from cardiovascular diseases. Given their efficacy in improving patient outcomes, CRPs may have salutary potential for the treatment of cardiovascular sequelae of long-COVID. Indeed, there are several public and private initiatives testing the potential of CRPs in treating fatigue and dysautonomia in long-COVID subjects. The application of these established rehabilitation techniques to COVID-19 cardiovascular syndrome represents a promising approach to improving functional capacity and quality of life. In this brief review, we will focus on the long-lasting cardiovascular and autonomic sequelae occurring after COVID-19 infection, as well as exploring the potential of classic and novel CRPs for managing COVID-19 cardiovascular syndrome. Finally, we expect this review will encourage health care professionals and private/public health organizations to evaluate/implement non-invasive techniques for the management of COVID-19 cardiovascular sequalae.

Does COVID-19 Escalate Aging Process? A Possible Concern

A key challenge after the COVID-19 pandemic will be managing the long-term sequelae for the millions of individuals who recover from the disease. Based on the available evidence, our hypothesis is that the SARS-CoV-2 pandemic and its long-term complications will lead to premature aging (in terms of health) of many people in the world. Obviously, to maintain appropriate public health and prevent poor health-care services, countries should think and plan about the health problems and the long-term consequences of SARS-CoV-2 after controlling the COVID-19 pandemic.

The interplay of post-acute COVID-19 syndrome and aging: a biological, clinical and public health approach

The post-acute COVID-19 syndrome (PACS) is characterized by the persistence of fluctuating symptoms over three months from the onset of the possible or confirmed COVID-19 acute phase. Current data suggests that at least 10% of people with previously documented infection may develop PACS, and up to 50-80% of prevalence is reported among survivors after hospital discharge. This viewpoint will discuss various aspects of PACS, particularly in older adults, with a specific hypothesis to describe PACS as the expression of a modified aging trajectory induced by SARS CoV-2. This hypothesis will be argued from biological, clinical and public health view, addressing three main questions: (i) does SARS-CoV-2-induced alterations in aging trajectories play a role in PACS?; (ii) do people with PACS face immuno-metabolic derangements that lead to increased susceptibility to age-related diseases?; (iii) is it possible to restore the healthy aging trajectory followed by the individual before pre-COVID?. A particular focus will be given to the well-being of people with PACS that could be assessed by the intrinsic capacity model and support the definition of the healthy aging trajectory.

Post-COVID syndrome, inflammation, and diabetes

The raging COVID-19 pandemic is in its third year of global impact. The SARS CoV 2 virus has a high rate of spread, protean manifestations, and a high morbidity and mortality in individuals with predisposing risk factors. The pathophysiologic mechanisms involve a heightened systemic inflammatory state, cardiometabolic derangements, and varying degrees of glucose intolerance. The latter can be evident as significant hyperglycemia leading to new-onset diabetes or worsening of preexisting disease. Unfortunately, the clinical course beyond the acute phase of the illness may persist in the form of a variety of symptoms that together form the so-called "Long COVID" or "Post-COVID Syndrome". It is thought that a chronic, low-grade inflammatory and immunologic state persists during this phase, which may last for weeks or months. Although numerous insights have been gained into COVID-related hyperglycemia and diabetes, its prediction, course, and management remain to be fully elucidated.

Opposite Effect of Thyroid Hormones on Oxidative Stress and on Mitochondrial Respiration in COVID-19 Patients

Background: Thyroid hormones (TH)s are master regulators of mitochondrial activity and biogenesis. Nonthyroidal illness syndrome (NTIS) is generally considered an adaptative response to reduced energy that is secondary to critical illness, including COVID-19. COVID-19 has been associated with profound changes in the cell energy metabolism, especially in the cells of the immune system, with a central role played by the mitochondria, considered the power units of every cell. Infection by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) affects and alters mitochondrial functions, both to influence its intracellular survival and to evade host immunity. Aim of the study: This study was undertaken to analyze the oxidative balance and mitochondrial respiration in COVID-19 patients with and without NTIS to elucidate the role that thyroid hormones (TH)s play in this context. Methods: In our cohort of 54 COVID-19 patients, admitted to our University Hospital during the COVID-19 pandemic, we evaluated the generation of reactive oxygen species (ROS) by measuring the serum levels of derivatives of reactive oxygen metabolites (dROMs), and we analyzed the antioxidant capacity by measuring the serum biological antioxidant potential (BAP). We then analyzed the mitochondrial respiration in peripheral blood mononuclear cells (PBMC)s of 28 of our COVID-19 patients, using the seahorse instrument (Agilent). Results were correlated with the serum levels of THs and, in particular, of FT3. In addition, the role of T3 on bioelectrical impedance analysis (BIA) and mitochondrial respiration parameters was directly evaluated in two COVID-19 patients with NTIS, in which treatment with synthetic liothyronine (LT3) was given both in vivo and in vitro. Results: In our COVID-19 patients with NTIS, the dROMs values were significantly lower and the BAP values were significantly higher. Consequently, the oxidative stress index (OSi), measured as BAP/dROMs ratio was reduced compared to that observed in COVID-19 patients without NTIS, indicating a protective role exerted by NTIS on oxidative stress. In our COVID-19 patients, the mitochondrial respiration, measured in PBMCs, was reduced compared to healthy controls. Those with NTIS showed a reduced maximal respiratory capacity and a reduced proton leak, compared to those with normal FT3 serum values. Such lowered mitochondrial respiratory capacity makes the cells more vulnerable to bioenergetic exhaustion. In a pilot study involving two COVID-19 patients with NTIS, we could reinforce our previous observation regarding the role of T3 in the maintenance of adequate peripheral hydroelectrolytic balance. In addition, in these two patients, we demonstrated that by treating their PBMCs with LT3, both in vitro and in vivo, all mitochondrial respiration parameters significantly increased. Conclusions: Our results regarding the reduction in the serum levels of the reactive oxygen species (ROS) of COVID-19 patients with NTIS support the hypothesis that NTIS could represent an adaptative response to severe COVID-19. However, beside this beneficial effect, we demonstrate that, in the presence of an acute reduction of FT3 serum levels, the mitochondrial respiration is greatly impaired, with a consequent establishment of a hypoenergetic state of the immune cells that may hamper their capacity to react to massive viral infection.

Kynurenine serves as useful biomarker in acute, Long- and Post-COVID-19 diagnostics

Introduction

In patients with SARS-CoV-2, innate immunity is playing a central role, depicted by hyperinflammation and longer lasting inflammatory response. Reliable inflammatory markers that cover both acute and long-lasting COVID-19 monitoring are still lacking. Thus, we investigated one specific inflammatory marker involved as one key player of the immune system, kynurenine (Kyn), and its use for diagnosis/detection of the Long-/Post-COVID syndrome in comparison to currently used markers in both serum and saliva samples.

Material and methods

The study compromised in total 151 inpatients with a SARS-CoV-2 infection hospitalized between 03/2020 and 09/2021. The group NC (normal controls) included blood bank donors (n=302, 144f/158m, mean age 47.1 ± 18.3 years (range 18-75)). Two further groups were generated based on Group A (n=85, 27f/58m, mean age 63.1 ± 18.3 years (range 19-90), acute admission to the hospital) and Group B (n=66, 22f/44m, mean age 66.6 ± 17.6 years (range 17-90), admitted either for weaning or for rehabilitation period due to Long-COVID symptoms/syndrome). Plasma concentrations of Kyn, C-Reactive Protein (CRP) and interleukin-6 (IL-6) were measured on admission. In Group B we determined Kyn 4 weeks after the negative PCR-test. In a subset of patients (n=11) concentrations of Kyn and CRP were measured in sera and saliva two, three and four months after dismission. We identified 12 patients with Post-COVID symptoms >20 weeks with still significant elevated Kyn-levels.

Results

Mean values for NC used as reference were 2.79 ± 0.61 µM, range 1.2-4.1 µM. On admission, patients showed significantly higher concentrations of Kyn compared to NC (p-values < 0.001). Kyn significantly correlated with IL-6 peak-values (r=0.411; p-values <0.001) and CRP (r=0.488, p-values<0.001). Kyn values in Group B (Long-/Post-COVID) showed still significant higher values (8.77 ± 1.72 µM, range 5.5-16.6 µM), whereas CRP values in Group B were in the normal range.

Conclusion

Serum and saliva Kyn are reflecting the acute and long-term pathophysiology of the SARS-CoV-2 disease concerning the innate immune response and thus may serve a useful biomarker for diagnosis and monitoring both Long- and Post-COVID syndrome and its therapy.

The long COVID syndrome: A conundrum for the allergist/immunologist

Background: The long coronavirus disease 2019 (COVID-19) syndrome includes a group of patients who, after infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) exhibit lingering mild-to-moderate symptoms and develop medical complications that can have lasting health problems. Objective: The purpose of this report was to examine the current body of evidence that deals with the relationship of COVID-19 infection with the long COVID syndrome to define the possible immunologic mechanisms involved in the pathogenesis of long COVID and to describe potential strategies for the diagnosis and clinical management of the condition. Methods: Extensive research was conducted in medical literature data bases by applying terms such as long COVID, post-COVID-19 condition, pathogenesis of long COVID, management of the long COVID syndrome. Results: The post-COVID conditions, a more recent and less anxiety-inducing term for the patient than long COVID or "long haul," is an umbrella term for a wide range of physical and mental health symptoms similar to those seen in patients with the myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS), experienced by some patients and are present ≥ 4 weeks after SARS-CoV-2 infection. Although the precise reason why long COVID develops is unknown, one of the major causes is thought to be related to chronic inflammation with overproduction of inflammatory cytokines responsible for the symptoms of the disorder. Conclusion: Long COVID is a growing burden for millions of patients, health-care providers, and global health-care systems, and is a particular challenge for the allergist/immunologist. Many survivors of COVID-19 struggle with multiple symptoms, increased disability, reduced function, and poor quality of life. The allergist/immunologist can assist the total health-care team's efforts in providing a comprehensive and coordinated approach to the management of these patients by promoting comprehensive vaccination and rehabilitation and social services that focus on improving physical, mental, and social well-being, and by establishing partnerships with specialists and other health-care professionals who can provide behavioral, lifestyle, and integrative approaches that may have much to offer in helping patients cope with their symptoms.

Effects of a Multicomponent Exercise Program on Improving Frailty in Post-COVID-19 Older Adults after Intensive Care Units: A Single-Group Retrospective Cohort Study

Background: Older adult patients with post-COVID-19 syndrome present greater physical impairment accompanied by frailty than younger patients, which is why multicomponent exercise programs (MEP) are recommended for their positive effects on improving frailty and physical capacity. The aim of this study was to evaluate the effects of a short MEP (Vivifrail; <4 weeks) on improving frailty in post-COVID-19 older adults after intensive care units. Methods: To develop a retrospective cohort study, data were collected from the functional gait training program based on selected Vivifrail MEP in a single-group and applied to patients admitted with a diagnosis of post-COVID-19 functional impairment. The MEP was carried out for 3 weeks, with daily sessions lasting 40 min. Patients included were assessed at the beginning and at the end of the protocol by using the Short Performance Physical Battery (SPPB), the number of falls in the last year, the number of falls with medical attention, the Timed Up and Go (TUG) test, the presence of dementia, the Trunk Control Test (TCT), the Tinetti balance and gait test, Barthel Index, Medical Research Council Sum Score (MRCSS) and handgrip strength dynamometry. Results: The results of this study show statistically significant improvements in physical fitness and frailty with increases in the Short Physical Performance Battery (Z = 9.12, p < 0.001) by means of the MET applied in its short version (<4 weeks) showing even clinically relevant improvements (>2.5 points). Statistically significant improvements were also found in Medical Research Council Sum Score (Z = 12.345, p < 0.001), Barthel Index Score (Z = 12.272, p < 0.001), Trunk Control Test (Z = 12. 36, p < 0.001), Tinetti−POMA (Z = 12.293, p < 0.001) including the balance (Z = 12.11, p < 0.001), gait (Z = 12.164, p < 0.001) subscales and in the hand dynamometry (Z = 12.172, p < 0.001). Conclusions: The selected Vivifrail MEP is effective and safe for improving frailty in post-COVID-19 older adult’s patients.

Connecting aging biology and inflammation in the omics era

Aging is characterized by the accumulation of damage to macromolecules and cell architecture that triggers a proinflammatory state in blood and solid tissues, termed inflammaging. Inflammaging has been implicated in the pathogenesis of many age-associated chronic diseases as well as loss of physical and cognitive function. The search for mechanisms that underlie inflammaging focused initially on the hallmarks of aging, but it is rapidly expanding in multiple directions. Here, we discuss the threads connecting cellular senescence and mitochondrial dysfunction to impaired mitophagy and DNA damage, which may act as a hub for inflammaging. We explore the emerging multi-omics efforts that aspire to define the complexity of inflammaging - and identify molecular signatures and novel targets for interventions aimed at counteracting excessive inflammation and its deleterious consequences while preserving the physiological immune response. Finally, we review the emerging evidence that inflammation is involved in brain aging and neurodegenerative diseases. Our goal is to broaden the research agenda for inflammaging with an eye on new therapeutic opportunities.

Platelet-leukocyte crosstalk in COVID-19: How might the reciprocal links between thrombotic events and inflammatory state affect treatment strategies and disease prognosis?

Platelet-leukocyte crosstalk is commonly manifested by reciprocal links between thrombosis and inflammation. Platelet thrombus acts as a reactive matrix that recruits leukocytes to the injury site where their massive accumulation, activation and migration promote thrombotic events while triggering inflammatory responses. As a life-threatening condition with the associations between inflammation and thrombosis, COVID-19 presents diffuse alveolar damage due to exaggerated macrophage activity and cytokine storms. These events, together with direct intracellular virus invasion lead to pulmonary vascular endothelialitis, cell membranes disruption, severe endothelial injury, and thrombosis. The developing pre-alveolar thrombus provides a hyper-reactive milieu that recruits circulating leukocytes to the injury site where their activation contributes to thrombus stabilization and thrombosis propagation, primarily through the formation of Neutrophil extracellular trap (NET). NET fragments can also circulate and deposit in further distance where they may disseminate intravascular thrombosis in severe cases of disease. Thrombi may also facilitate leukocytes migration into alveoli where their accumulation and activation exacerbate cytokine storms and tissue damage, further complicating the disease. Based on these mechanisms, whether an effective anti-inflammatory protocol can prevent thrombotic events, or on the other hand; efficient antiplatelet or anticoagulant regimens may be associated with reduced cytokine storms and tissue damage, is now of interests for several ongoing researches. Thus shedding more light on platelet-leukocyte crosstalk, the review presented here discusses the detailed mechanisms by which platelets may contribute to the pathogenesis of COVID-19, especially in severe cases where their interaction with leukocytes can intensify both inflammatory state and thrombosis in a reciprocal manner.

Antioxidant, anti-inflammatory and immunomodulatory roles of vitamins in COVID-19 therapy

oxidative stress is caused by an abundant generation of reactive oxygen species, associated to a diminished capacity of the endogenous systems of the organism to counteract them. Activation of pro-oxidative pathways and boosting of inflammatory cytokines are always encountered in viral infections, including SARS-CoV-2. So, the importance of counteracting cytokine storm in COVID-19 pathology is highly important, to hamper the immunogenic damage of the endothelium and alveolar membranes. Antioxidants prevent oxidative processes, by impeding radical species generation. It has been proved that vitamin intake lowers oxidative stress markers, alleviates cytokine storm and has a potential role in reducing disease severity, by lowering pro-inflammatory cytokines, hampering hyperinflammation and organ failure. For the approached compounds, direct antiviral roles are also discussed in this review, as these activities encompass secretion of antiviral peptides, modulation of angiotensin-converting enzyme 2 receptor expression and interaction with spike protein, inactivation of furin protease, or inhibition of pathogen replication by nucleic acid impairment induction. Vitamin administration results in beneficial effects. Nevertheless, timing, dosage and mutual influences of these micronutrients should be carefullly regarded.

Association between inflammatory cytokines and anti-SARS-CoV-2 antibodies in hospitalized patients with COVID-19

BACKGROUND

COVID-19 patients may experience "cytokine storm" when human immune system produces excessive cytokines/chemokines. However, it remains unclear whether early responses of inflammatory cytokines would lead to high or low titers of anti-SARS-CoV-2 antibodies.

METHODS

This retrospective study enrolled a cohort of 272 hospitalized patients with laboratory-confirmed SARS-CoV-2. Laboratory assessments of serum cytokines (IL-2R, IL-6, IL-8, IL-10, TNF-α), anti-SARS-CoV-2 IgG/IgM antibodies, and peripheral blood biomarkers were conducted during hospitalization.

RESULTS

At hospital admission, 36.4% patients were severely ill, 51.5% patients were ≥ 65 years, and 60.3% patients had comorbidities. Higher levels of IL-2R and IL-6 were observed in older patients (≥65 years). Significant differences of IL-2R (week 2 to week ≥5 from symptom onset), IL-6 (week 1 to week ≥5), IL-8 (week 2 to week ≥5), and IL-10 (week 1 to week 3) were observed between moderately-ill and severely ill patients. Anti-SARS-CoV-2 IgG titers were significantly higher in severely ill patients than in moderately ill patients, but such difference was not observed for IgM. High titers of early-stage IL-6, IL-8, and TNF-α (≤2 weeks after symptom onset) were positively correlated with high titers of late-stage IgG (≥5 weeks after symptom onset). Deaths were mostly observed in severely ill older patients (45.9%). Survival analyses revealed risk factors of patient age, baseline COVID-19 severity, and baseline IL-6 that affected survival time, especially in severely ill older patients.

CONCLUSION

Early responses of elevated cytokines such as IL-6 reflect the active immune responses, leading to high titers of IgG antibodies against COVID-19.

COVID-19 and chronic fatigue syndrome: An endocrine perspective

Patients recovering from COVID-19 may have persistent debilitating symptoms requiring long term support through individually tailored cardiopulmonary and psychological rehabilitation programs. Clinicians need to be aware about the likely long-term complications and their diagnostic assessments to help identify any occult problems requiring additional help. Endocrinological evaluations should be considered as part of the armamentarium in the management of such individuals with diligent cognizance about the involvement of the hypothalamo-pituitary-adrenal (HPA) axis, adrenal and thyroid function. We here review the literature and potential pathophysiological mechanisms involved in and related to post COVID-19 symptoms with an emphasis on endocrine function.

REHABILITATION DURING THE COVID-19 PANDEMIC

The COVID-19 pandemic has affected the entire healthcare system, from emergency care, intensive care units, internal medicine wards, outpatient care to home care. The pandemic continues and brings a large number of patients with COVID-19-associated postintensive care syndrome suffering from physical, mental and cognitive impairments that threaten their return to normal life. The complexity and severity of illness in patients recovering from severe COVID-19 requires a coordinated and systematic approach to be applied as early as possible during the recovery phase. Considering the multiorgan dysfunction, debility, pulmonary, neurological, neuromuscular and cognitive complications, rehabilitation professionals can play an important role in the recovery process for individuals with COVID-19. Complications of COVID-19 can be reduced by 1) multidisciplinary rehabilitation, which begins early and continues throughout the hospital stay, 2) providing patient/family education for self-care after discharge from inpatient rehabilitation, and 3) continuing rehabilitation care in the outpatient setting, and at home either in person or with the help of telerehabilitation.

Complications Post-COVID-19 and Risk Factors among Patients after Six Months of a SARS-CoV-2 Infection: A Population-Based Prospective Cohort Study

In October 2020, we conducted a population-based prospective cohort study to determine post-COVID-19 complications, recovery, return to usual health, and associated risk factors in 536 cases of COVID-19 outbreak in Borriana (Spain) by administering an epidemiological questionnaire via phone interviews. A total of 484 patients participated (90.3%), age mean 37.2 ± 17.1 years, and 301 females (62.2%). Mild illness was the most common COVID-19 manifestation. After six months, 160 patients (33.1%) suffered at least one complication post-COVID-19, and 47 (29.4%) of them sought medical assistance. The most frequent persistent symptoms were hair loss, fatigue, loss of smell or taste, and headache. Risk factors associated with a complication were female sex (adjusted relative risk, [aRR] = 1.93 95% confidence interval [CI] 1.41-2.65), age 35 years and above (aRR = 1.50 95% CI 1.14-1.99), B blood group (aRR = 1.51 95% CI 1.04-2.16), current smoker (RR = 1.61 95% CI 1.02-2.54), and at least a COVID-19 exposure (aRR = 2.13 95% CI 1.11-4.09). Male sex, age younger than 35 years, and low COVID-19 exposures were associated with better recovery and return to usual health. A third of patients presented persistent symptoms compatible with the long-COVID-19 syndrome. In conclusion, an active medical follow-up of post-COVID-19 patients must be implemented.

Cardiac Rehabilitation in Patients with Peripheral Artery Disease-A Literature Review in COVID-19 Era

Cardiac rehabilitation (CR) is an integral part of the management of various cardiovascular disease such as coronary artery disease (CAD), peripheral artery disease (PAD), or chronic heart failure (CHF), with proven morbidity and mortality benefits. This article aims to review and summarize the scientific literature related to cardiac rehabilitation programs for patients with PAD and how they were adapted during the COVID-19 pandemic. The implementation of CR programs has been problematic since the COVID-19 pandemic due to social distancing and work-related restrictions. One of the main challenges for physicians and health systems alike has been the management of PAD patients. COVID-19 predisposes to coagulation disorders that can lead to severe thrombotic events. Home-based walking exercises are more accessible and easier to accept than supervised exercise programs. Cycling or other forms of exercise are more entertaining or challenging alternatives to exercise therapy. Besides treadmill exercises, upper- and lower-extremity ergometry also has great functional benefits, especially regarding walking endurance. Supervised exercise therapy has a positive impact on both functional capacity and also on the quality of life of such patients. The most effective manner to acquire this seems to be by combining revascularization therapy and supervised exercise. Rehabilitation programs proved to be a mandatory part of the integrative approach in these cases, increasing quality of life, and decreasing stress levels, depression, and anxiety.

The role of single-domain antibodies (or nanobodies) in SARS-CoV-2 neutralization

The severe acute respiratory syndrome (SARS-CoV-2), a newly emerging of coronavirus, continues to infect humans in the absence of a viable treatment. Neutralizing antibodies that disrupt the interaction of RBD and ACE2 has been under the spotlight as a way of developing the COVID-19 treatment. Some animals, such as llamas, manufacture heavy-chain antibodies that have a single variable domain (VHH) instead of two variable domains (VH/VL) as opposed to typical antibodies. Nanobodies are antigen-specific, single-domain, changeable segments of camelid heavy chain-only antibodies that are recombinantly produced. These types of antibodies exhibit a wide range of strong physical and chemical properties, like high solubility, and stability. The VHH's high-affinity attachment to the receptor-binding domain (RBD) allowed the neutralization of SARS-CoV-2. To tackle COVID-19, some nanobodies are being developed against SARS-CoV-2, some of which have been recently included in clinical trials. Nanobody therapy may be useful in managing the COVID-19 pandemic as a potent and low-cost treatment. This paper describes the application of nanobodies as a new class of recombinant antibodies in COVID-19 treatment.

Are Older People Really More Susceptible to SARS-CoV-2?

Since the outbreak, COVID-19 has spread rapidly across the globe due to its high infectivity and lethality. Age appears to be one of the key factors influencing the status and progression of SARS-CoV-2 infection, as multiple reports indicated that the majority of COVID-19 infections and severe cases are elderly. Most people simply assume that the elderly are more susceptible to SARS-CoV-2 than the young, but the mechanism behind it is still open to question. The older and younger people are at similar risk of infection because their infection process is the same and they must be exposed to the virus first. However, whether they will get sick after exposure to the virus and how their disease progresses depend on their immune mechanisms. In older populations, inflammation and immune aging reduce their ability to resist SARS-CoV-2 infection. Meanwhile, under the influence of comorbidities, ACE2 receptor and various cytokines undergo corresponding changes, thus accelerating the entry, replication, and transmission of SARS-CoV-2 in the body, promoting disease progression, and leading to severe illness and even death. In addition, the relatively fragile mental state of the elderly can also affect their timely recovery from COVID-19. Therefore, once older people are infected with SARS-CoV-2, they are more prone to severe illness and death with a poor prognosis, and they should strengthen protection to avoid exposure to the virus.

[Postcovid cognitive impairment]

This review addresses current issues in post-COVID syndrome with a focus on neurocognitive impairment. The results of studies on complications in patients of different ages and health statuses recovered from mild to severe COVID-19 are discussed. Current data on the pathogenetic mechanisms of the development of various post-COVID disorders are presented, including a detailed discussion of central nervous system damage. The paper summarizes data on the relationship between neurocognitive disorders and accelerated cell aging, chronic nonspecific inflammation, and reduced neuroplasticity in the central nervous system. The main pathogenetic ways to prevent COVID-related complications, including neuronal tissue damage and the prospects for managing such patients are discussed. The choice of pathogenetic therapy in patients with neurocognitive impairment in the post-COVID period is assessed. The main benefits of choline alfoscerate therapy for neurocognitive impairment in patients with post-COVID syndrome are discussed.

RBC-hitchhiking chitosan nanoparticles loading methylprednisolone for lung-targeting delivery

Hyper-inflammation associated with cytokine storm syndrome causes high mortality in patients with COVID-19. Glucocorticoids, such as methylprednisolone sodium succinate (MPSS), effectively inhibit this inflammatory response. However, frequent and chronic administration of glucocorticoids at high doses leads to hormone dependence and serious side effects. The aim of the present study was to combine nanoparticles with erythrocytes for the targeted delivery of MPSS to the lungs. Chitosan nanoparticles loading MPSS (MPSS-CSNPs) were prepared and adsorbed on the surface of red blood cells (RBC-MPSS-CSNPs) by non-covalent interaction. In vivo pharmacokinetic study indicated that RBC-hitchhiking could significantly reduce the plasma concentration of the drug and prolong the circulation time. The mean residence time (MRT) and area under the curve (AUC) of the RBC-MPSS-CSNPs group were significantly higher than those of the MPSS-CSNPs group and the MPSS injection group. Moreover, in vivo imaging and tissue distribution indicated that RBC-hitchhiking facilitated the accumulation of nanoparticles loading fluorescein in the lung, preventing uptake of these nanoparticles by the liver. Furthermore, compared with the MPSS-CSNPs and MPSS treatment groups, treatment with RBC-MPSS-CSNPs considerably inhibited the production of inflammatory cytokines such as TNF-α and IL-6, and consequently attenuated lung injury induced by lipopolysaccharide in rats. Therefore, RBC-hitchhiking is a potentially effective strategy for the delivery of nanoparticles to the lungs for the treatment of acute lung injury and acute respiratory distress syndrome.

The critical role of mesenchymal stromal/stem cell therapy in COVID-19 patients: An updated review

New coronavirus disease 2019 (COVID-19), as a pandemic disaster, has drawn the attention of researchers in various fields to discover suitable therapeutic approaches for the management of COVID-19 patients. Currently, there are many worries about the rapid spread of COVID-19; there is no approved treatment for this infectious disease, despite many efforts to develop therapeutic procedures for COVID-19. Emerging evidence shows that mesenchymal stromal/stem cell (MSC) therapy can be a suitable option for the management of COVID-19. These cells have many biological features (including the potential of differentiation, high safety and effectiveness, secretion of trophic factors and immunoregulatory features) that make them suitable for the treatment of various diseases. However, some studies have questioned the positive role of MSC therapy in the treatment of COVID-19. Accordingly, in this paper, we will focus on the therapeutic impacts of MSCs and their critical role in cytokine storm of COVID-19 patients.

[Guideline S1: Long COVID: Diagnostics and treatment strategies]

This guideline comprises the state of science at the time of the editorial deadline. In view of the high turnover of knowledge the guideline is designed as a living guideline. The main objective was to provide a tool for the use in primary care, being considered well suited as a first point of entry and for the provision of care. The guideline gives recommendations on the differential diagnosis of symptoms following SARS-CoV‑2 infection, on their therapeutic options, as well as for guidance and care of the patients concerned. It also offers advice concerning return to daily life and rehabilitation. Long COVID being a very variable condition, we chose an interdisciplinary approach.

The microvascular hypothesis underlying neurologic manifestations of long COVID-19 and possible therapeutic strategies

With the ongoing distribution of the coronavirus disease (COVID) vaccines, the pandemic of our age is ending, leaving the world to deal with its well-documented aftereffects. Long COVID comprises a variety of symptoms, of which the neurological component prevails. The most permeating theory on the genesis of these symptoms builds upon the development of microvascular dysfunction similar to that seen in numerous vascular diseases such as diabetes. This can occur through the peripheral activation of angiotensin-converting enzyme 2 receptors, or through exacerbations of pro-inflammatory cytokines that can remain in circulation even after the infection diminishes. Several drugs have been identified to act on the neurovascular unit to promote repair, such as gliptins, and others. They also succeeded in improving neurologic outcome in diabetic patients. The repurposing of such drugs for treatment of long COVID-19 can possibly shorten the time to recovery of long COVID-19 syndrome.

Depressive and Neurocognitive Disorders in the Context of the Inflammatory Background of COVID-19

The dysfunctional effects of the coronavirus disease 2019 (COVID-19) infection on the nervous system are established. The manifestation of neuropsychiatric symptoms during and after infection is influenced by the neuroinvasive and neurotrophic properties of SARS-CoV-2 as well as strong inflammation characterised by a specific "cytokine storm". Research suggests that a strong immune response to a SARS-CoV-2 infection and psychological stressors related to the pandemic may cause chronic inflammatory processes in the body with elevated levels of inflammatory markers contributing to the intensification of neurodegenerative processes. It is suggested that neuroinflammation and associated central nervous system changes may significantly contribute to the etiopathogenesis of depressive disorders. In addition, symptoms after a COVID-19 infection may persist for up to several weeks after an acute infection as a post-COVID-19 syndrome. Moreover, previous knowledge indicates that among SSRI (selective serotonin reuptake inhibitor) group antidepressants, fluoxetine is a promising drug against COVID-19. In conclusion, further research, observation and broadening of the knowledge of the pathomechanism of a SARS-CoV-2 infection and the impact on potential complications are necessary. It is essential to continue research in order to assess the long-term neuropsychiatric effects in COVID-19 patients and to find new therapeutic strategies.

Validation of the effectiveness of SARS-CoV-2 vaccines in older adults in "real-world" settings

The rapidity of SARS-CoV-2 vaccination around the world has substantially reduced the number of new cases of COVID-19 and their severity in highly vaccinated countries. The unanticipated efficacy of SARS-CoV-2 vaccines in older adults has been very encouraging but the longevity of vaccine immunity is currently unknown and protection against emerging variants may be lower. Adoptive immunotherapy with neutralizing mAb may offer an alternative for poor vaccine responders, while the mechanisms underlying failure to respond are still unclear. Further studies of B and T cell responses and their regulation particularly in older populations will provide a more solid foundation to develop suitable approaches to optimize vaccine responses of older adults who fail to mount a durable response.

The Platelet Role in Severe and Fatal Forms of COVID-19

On December 31, 2019, the World Health Organization received a report of several pneumonia cases in Wuhan, China. The causative agent was later confirmed as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Since then, the SARS-CoV-2 virus has spread throughout the world, giving rise in 2020 to the 2019 coronavirus (COVID-19) pandemic, which, according to the world map of the World Health Organization, has, until May 18, 2021, infected 163,312,429 people and caused 3,386,825 deaths throughout the world. Most critical patients progress rapidly to acute respiratory distress syndrome (ARDS) and, in underlying form, to septic shock, irreversible metabolic acidosis, blood coagulation dysfunction, or hemostatic and thrombotic anomalies have been reported as the leading causes of death due to COVID-19. The main findings in severe and fatal COVID-19 patients make it clear that platelets play a crucial role in developing severe disease cases. Platelets are the enucleated cells responsible for hemostasis and thrombi formation; thus, platelet hyperreactivity induced by pro-inflammatory microenvironments contributes to the "cytokine storm" that characterizes the more aggressive course of COVID- 19.

Network Topology of Biological Aging and Geroscience-Guided Approaches to COVID-19

Aging has emerged as the greatest and most prevalent risk factor for the development of severe COVID-19 infection and death following exposure to the SARS-CoV-2 virus. The presence of multiple co-existing chronic diseases and conditions of aging further enhances this risk. Biological aging not only enhances the risk of chronic diseases, but the presence of such conditions further accelerates varied biological processes or "hallmarks" implicated in aging. Given growing evidence that it is possible to slow the rate of many biological aging processes using pharmacological compounds has led to the proposal that such geroscience-guided interventions may help enhance immune resilience and improve outcomes in the face of SARS-CoV-2 infection. Our review of the literature indicates that most, if not all, hallmarks of aging may contribute to the enhanced COVID-19 vulnerability seen in frail older adults. Moreover, varied biological mechanisms implicated in aging do not function in isolation from each other, and exhibit intricate effects on each other. With all of these considerations in mind, we highlight limitations of current strategies mostly focused on individual single mechanisms, and we propose an approach which is far more multidisciplinary and systems-based emphasizing network topology of biological aging and geroscience-guided approaches to COVID-19.

Unraveling the Mystery Surrounding Post-Acute Sequelae of COVID-19

More than one year since its emergence, corona virus disease 2019 (COVID-19) is still looming large with a paucity of treatment options. To add to this burden, a sizeable subset of patients who have recovered from acute COVID-19 infection have reported lingering symptoms, leading to significant disability and impairment of their daily life activities. These patients are considered to suffer from what has been termed as “chronic” or “long” COVID-19 or a form of post-acute sequelae of COVID-19, and patients experiencing this syndrome have been termed COVID-19 long-haulers. Despite recovery from infection, the persistence of atypical chronic symptoms, including extreme fatigue, shortness of breath, joint pains, brain fogs, anxiety and depression, that could last for months implies an underlying disease pathology that persist beyond the acute presentation of the disease. As opposed to the direct effects of the virus itself, the immune response to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is believed to be largely responsible for the appearance of these lasting symptoms, possibly through facilitating an ongoing inflammatory process. In this review, we hypothesize potential immunological mechanisms underlying these persistent and prolonged effects, and describe the multi-organ long-term manifestations of COVID-19.