The untwining of immunosenescence and aging

Association between the C-reactive protein-albumin-lymphocyte index and all-cause mortality in Chinese older adults: a national cohort study based on CLHLS from 2014 to 2018

Background

The C-reactive protein-albumin-lymphocyte (CALLY) index, a novel inflammation-immune-nutritional biomarker, has not been comprehensively evaluated for mortality risk prediction in older populations. Here, we investigate the relationship between the CALLY index and all-cause mortality in Chinese adults aged ≥ 60 years.

Methods

Data were obtained from the 2014 to 2018 wave of the Chinese Longitudinal Healthy Longevity Survey (CLHLS). Upon applying a natural logarithmic transformation to the CALLY index, the lnCALLY was stratified into tertiles. Kaplan-Meier analysis and the log-rank test were employed to assess the cumulative survival probability across lnCALLY-stratified older adults populations. Cox proportional hazards regression was utilized to investigate the association between lnCALLY and all-cause mortality. Receiver operating characteristic (ROC) curves and area under the curve (AUC) values were conducted to evaluate the predictive capacity of lnCALLY for all-cause mortality. Restricted cubic splines (RCS) with four knots were applied to explore the potential non-linear dose-response association of lnCALLY with all-cause mortality. Subgroup analyses and sensitivity analyses were conducted to ensure validity.

Results

A total of 1,738 older adults participants were included in this cohort. Over a median follow-up of 3.3 years, 580 deaths (33.3%) occurred. The multivariable Cox regression demonstrated that the highest lnCALLY tertile was associated with a 40% reduced mortality risk compared to the lowest tertile [adjusted hazard ratio (HR) = 0.60, 95% confidence interval (CI): 0.49-0.73]. Kaplan-Meier curves revealed significantly higher survival probabilities in individuals with elevated lnCALLY (P < 0.001). Time-dependent ROC analysis showed that the AUC of lnCALLY for predicting all-cause mortality at 1-, 2-, and 3-year were 0.751, 0.746, and 0.762, respectively. RCS demonstrated an approximate "L"-shaped negative correlation between lnCALLY and all-cause mortality (P overall < 0.001, P non- linearity = 0.364). Subgroup and sensitivity analyses confirmed robustness, with no significant interactions observed across demographic or clinical strata.

Conclusion

These findings suggest that the CALLY index serves as a practical prognostic biomarker for monitoring survival in older populations, underscoring the interplay of inflammation, immunity, and nutrition in aging-related mortality.

Decoding brain aging trajectory: predictive discrepancies, genetic susceptibilities, and emerging therapeutic strategies

The global extension of human lifespan has intensified the focus on aging, yet its underlying mechanisms remain inadequately understood. The article highlights aspects of genetic susceptibility to impaired brain bioenergetics, trends in age-related gene expression related to neuroinflammation and brain senescence, and the impact of stem cell exhaustion and quiescence on accelerated brain aging. We also review the accumulation of senescent cells, mitochondrial dysfunction, and metabolic disturbances as central pathological processes in aging, emphasizing how these factors contribute to inflammation and disrupt cellular competition defining the aging trajectory. Furthermore, we discuss emerging therapeutic strategies and the future potential of integrating advanced technologies to refine aging assessments. The combination of several methods including genetic analysis, neuroimaging techniques, cognitive tests and digital twins, offer a novel approach by simulating and monitoring individual health and aging trajectories, thereby providing more accurate and personalized insights. Conclusively, the accurate estimation of brain aging trajectories is crucial for understanding and managing aging processes, potentially transforming preventive and therapeutic strategies to improve health outcomes in aging populations.

Inflammaging and Immunosenescence in the Post-COVID Era: Small Molecules, Big Challenges

Aging naturally involves a decline in biological functions, often triggering a disequilibrium of physiological processes. A common outcome is the altered response exerted by the immune system to counteract infections, known as immunosenescence, which has been recognized as a primary cause, among others, of the so-called long-COVID syndrome. Moreover, the uncontrolled immunoreaction leads to a state of subacute, chronic inflammatory state known as inflammaging, responsible in turn for the chronicization of concomitant pathologies in a self-sustaining process. Anti-inflammatory and immunosuppressant drugs are the current choice for the therapy of inflammaging in post-COVID complications, with contrasting results. The increasing knowledge of the biochemical pathways of inflammaging led to disclose new small molecules-based therapies directed toward different biological targets involved in inflammation, immunological response, and oxidative stress. Herein, paying particular attention to recent clinical data and preclinical literature, we focus on the role of endocannabinoid system in inflammaging, and the promising therapeutic option represented by the CB2R agonists, the role of novel ligands of the formyl peptide receptor 2 and ultimately the potential of newly discovered monoamine oxidase (MAO) inhibitors with neuroprotective activity in the treatment of immunosenescence.

Serious adverse events following immunization and predictors of mortality associated with COVID-19 vaccination in India: a secondary data analysis of nationwide causality assessments

Background

Vaccines against COVID-19 were viewed as a way out to the ongoing pandemic and were given the emergency use authorization in India to initiate mass vaccination in January 2021. This study aimed to investigate the serious adverse events following immunizations (AEFIs) reported for COVID-19 vaccines and to identify predictors of mortality among these cases from India.

Methods

A secondary data analysis was conducted on the causality assessment reports for the 2708 serious AEFIs published by the National AEFI Committee under the Immunization Division, Ministry of Health and Family Welfare, Government of India. The analysis included all 21 reports published up until May 2023. The primary outcome variable analyzed was the survival/death status of each AEFI case, with various covariates from the published documents considered in the analysis.

Results

The majority of the serious AEFIs assessed were either coincidental (1220, 45%) or undetermined/unclassifiable (781, 28.8%). The majority of the serious AEFIs were reported among recipients of Covishield (1891, 69.8%) followed by Covaxin (347, 12.8%). Among these, 1114 (42.1%) died while the remaining 1594 (58.9%) were hospitalized and recovered. Systematically, AEFIs involving the cardiovascular system (696, 31.3%) were the most common, followed by those affecting the respiratory system (288, 13%) and neuropsychiatric system (295, 13.3%) which had a significant association with age (p < 0.001) and gender (p < 0.001). On multivariable analysis, females (p = 0.001), younger age groups (p < 0.001), AEFIs whose causality was determined and classified (p < 0.001), AEFI involving gastrointestinal and neuropsychiatric system (p < 0.001), AEFIs reported from North and Western India (p = 0.001) and those occurring during the winter season (p < 0.05) had significantly lower odds of mortality.

Conclusion

Among the cohort of serious AEFIs reported, older age, male sex, undetermined or unclassifiable causality classification, and involvement of the cardiovascular system were associated with significantly higher odds of mortality and require close monitoring following vaccination.

Beyond the Hayflick limit: How microbes influence cellular aging

Cellular senescence, a complex biological process resulting in permanent cell-cycle arrest, is central to aging and age-related diseases. A key concept in understanding cellular senescence is the Hayflick Limit, which refers to the limited capacity of normal human cells to divide, after which they become senescent. Senescent cells (SC) accumulate with age, releasing pro-inflammatory and tissue-remodeling factors collectively known as the senescence-associated secretory phenotype (SASP). The causes of senescence are multifaceted, including telomere attrition, oxidative stress, and genotoxic damage, and they extend to influences from microbial sources. Research increasingly emphasizes the role of the microbiome, especially gut microbiota (GM), in modulating host senescence processes. Beneficial microbial metabolites, such as short-chain fatty acids (SCFAs), support host health by maintaining antioxidant defenses and reducing inflammation, potentially mitigating senescence onset. Conversely, pathogenic bacteria like Pseudomonas aeruginosa and Helicobacter pylori introduce factors that damage host DNA or increase ROS, accelerating senescence via pathways such as NF-κB and p53-p21. This review explores the impact of bacterial factors on cellular senescence, highlighting the role of specific bacterial toxins in promoting senescence. Additionally, it discusses how dysbiosis and the loss of beneficial microbial species further contribute to age-related cellular deterioration. Modulating the gut microbiome to delay cellular senescence opens a path toward targeted anti-aging strategies. This work underscores the need for deeper investigation into microbial influence on aging, supporting innovative interventions to manage and potentially reverse cellular senescence.

Aging and infectious diseases in myasthenia gravis

Over the past 120 years, mortality associated with myasthenia gravis (MG) has steadily decreased while the incidence of MG has increased. While mortality due to MG has been ≤5 % for at least the past 25 years, the prevalence of MG has increased. This increase in prevalence of MG may be due, in part, to improvements in diagnostics but also to an aging global population and immunosenescence as the largest increases in MG prevalence have been in patients ≥65 years old. In fact, a "very late-onset" subtype of MG has been proposed for patients diagnosed at or after age 65 years. These patients are predominantly anti-AChR antibody positive and thymoma negative. Preferred therapeutic options differ based on age at MG onset. Immunosenescence may play a role not only in MG etiology but also in the increased susceptibility of MG patients to infection. Immunosuppressive effects of MG therapies can also increase vulnerability to infection. Despite the improvements in MG treatment, mortality in MG patients remains higher than in the non-MG population. This is partly due to increased vulnerability to infection but also due to infection acting as a precipitating factor for MG exacerbation or crisis. The increased infection risk inherent with MG and the increased risk resulting from some therapies calls for increased diligence in monitoring and treating infections in MG patients.

Immune aging and infectious diseases

ABSTRACT

The rise in global life expectancy has led to an increase in the older population, presenting significant challenges in managing infectious diseases. Aging affects the innate and adaptive immune systems, resulting in chronic low-grade inflammation (inflammaging) and immune function decline (immunosenescence). These changes would impair defense mechanisms, increase susceptibility to infections and reduce vaccine efficacy in older adults. Cellular senescence exacerbates these issues by releasing pro-inflammatory factors, further perpetuating chronic inflammation. Moreover, comorbidities, such as cardiovascular disease and diabetes, which are common in older adults, amplify immune dysfunction, while immunosuppressive medications further complicate responses to infections. This review explores the molecular and cellular mechanisms driving inflammaging and immunosenescence, focusing on genomic instability, telomere attrition, and mitochondrial dysfunction. Additionally, we discussed how aging-associated immune alterations influence responses to bacterial, viral, and parasitic infections and evaluated emerging antiaging strategies, aimed at mitigating these effects to improve health outcomes in the aging population.

Impaired Angiogenesis and Th1/Th17 Polarization: A Possible Explanation for the Decreased Incidence of Rosacea in the Aged

BACKGROUND

Rosacea is a common inflammatory skin disorder characterized by frequent facial flushing, erythema, telangiectasia, and papules, with a higher incidence observed in individuals aged 30-50 years and a tendency to decrease in the elderly. This age-related decline in incidence drew our attention to further explore the relationship between rosacea pathogenesis and aging.

METHODS

We analyzed the incidence of rosacea across 8340 individuals without systemic diseases. The effects of LL37-induced rosacea-like erythema and inflammation were evaluated in both young and aged mice. Immunofluorescence analysis was performed to assess microvessel density, whereas the expression levels of angiogenesis-related factors, including matrix metalloproteinases (MMPs) and vascular endothelial growth factor α (VEGFα), were quantified. Additionally, immune responses were assessed at both the cellular and systemic levels.

RESULTS

Aged mice displayed milder LL37-induced rosacea-like erythema and inflammation compared to their young counterparts. Immunofluorescence analysis revealed a decrease in microvessel density in rosacea models of the aged group. The expression of angiogenesis-related factors, including MMPs and VEGFα, was decreased in aged mice compared to young mice, indicating a reduced responsiveness to LL37 stimulation. Furthermore, we found that suppressed Th1- and Th17-polarized immune responses, one of the major pathogenic mechanisms of rosacea, were reduced in aged mice in response to LL37 stimulation at both cellular and systemic levels.

CONCLUSION

The findings suggest that impaired angiogenesis and attenuated Th1/Th17 immune responses underlie the age-related decline in rosacea incidence.

Reduced insulin/IGF-1 signalling upregulates two anti-viral immune pathways, decreases viral load and increases survival under viral infection in C. elegans

Reduced insulin/IGF-1 signalling (rIIS) improves survival across diverse taxa and there is a growing interest in its role in regulating immune function. Whilst rIIS can improve anti-bacterial resistance, the consequences for anti-viral immunity are yet to be systematically examined. Here, we show that rIIS in adult Caenorhabditis elegans increases the expression of key genes in two different anti-viral immunity pathways, whilst reducing viral load in old age, increasing survival and reducing rate-of-senescence under infection by naturally occurring positive-sense single-stranded RNA Orsay virus. We found that both drh-1 in the anti-viral RNA interference (RNAi) pathway and cde-1 in the terminal uridylation-based degradation of viral RNA pathway were upregulated in early adulthood under rIIS and increased anti-viral resistance was not associated with reproductive costs. Remarkably, rIIS increased anti-viral gene expression only in infected worms, potentially to curb the costs of constitutively upregulated immunity. RNA viruses are found across taxa from plants to mammals and we demonstrate a novel role for rIIS in regulating resistance to viral infection. We therefore highlight this evolutionarily conserved signalling pathway as a promising therapeutic target to improve anti-viral immunity.

Review of evidence linking exposure to environmental stressors and associated alterations in the dynamics of immunosenescence (ISC) with the global increase in multiple sclerosis (MS)

Historical survey confirms that, over the latter part of the 20th century, autoimmune-based diseases, including multiple sclerosis (MS), have shown a worldwide increase in incidence and prevalence. Analytical population studies have established that the exponential rise in MS is not solely due to improvements in diagnosis and healthcare but relates to an increase in autoimmune risk factors. Harmful environmental exposures, including non-communicable social determinants of health, anthropogens and indigenous or transmissible microbes, constitute a group of causal determinants that have been closely linked with the global rise in MS cases. Exposure to environmental stressors has profound effects on the adaptive arm of the immune system and, in particular, the associated intrinsic process of immune ageing or immunosenescence (ISC). Stressor-related disturbances to the dynamics of ISC include immune cell-linked untimely or premature (p) alterations and an accelerated replicative (ar) change. A recognised immune-associated feature of MS is pISC and current evidence supports the presence of an arISC during the disease. Moreover, collated data illustrates the immune-associated alterations that characterise pISC and arISC are inducible by environmental stressors strongly implicated in causing duplicate changes in adaptive immune cells during MS. The close relationship between exposure to environmental risk factors and the induction of pISC and arISC during MS offers a valid mechanism through which pro-immunosenescent stressors may act and contribute to the recorded increase in the global rate and number of new cases of the disease. Confirmation of alterations to the dynamics of ISC during MS provides a rational and valuable therapeutic target for the use of senolytic drugs to either prevent accumulation and enhance ablation of less efficient untimely senescent adaptive immune cells or decelerate the dysregulated process of replicative proliferation. A range of senotherapeutics are available including kinase and transcriptase inhibitors, rapalogs, flavanols and genetically-engineered T cells and the use of selective treatments to control emerging and unspecified aspects of pISC and arISC are discussed.

CD56bright NK cell expansion correlated with EBV reactivation control post allogeneic hematopoietic stem cell transplantation

Natural killer (NK) cells are equipped with anti-Epstein-Barr virus (EBV) function, however, whether EBV infection will affect NK cells reconstitution after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains unclear. To identify the characteristics of NK cells, we prospectively enrolled 11 patients who occurred EBV reactivation post allo-HSCT and 11 patients without EBV infection as control. We found that that EBV infection induced the expansion of CD56bright and NKG2A+KIR- NK subsets,and decreased the cytotoxicity function of NK cells. The frequency of NKG2A+KIR- NK cells were higher in patients who progressed into post-transplant lymphoproliferative disorder (PTLD) than EBV viremia patients, which also correlated with decreased proliferation and cytotoxic function. By screening the activation receptors of NK cells, we found the DNAM-1+CD56bright NK cells is significantly increased after EBV stimulation, further we demonstrated that DNAM-1 is essential for EBV induced NK cells activation as the cytokine release against EBV-transformed lymphoblastoid cell lines(EBV-LCLs) of CD56bright NK cells were significantly decreased after DNAM-1 blockade. NK cells infusion suppressed the progression of EBV-related tumor mice model. A prospective cohort indicated that old donor age was an independent risk factor for EBV infection. Rapid CD56bri expansion and high expression of DNAM-1 on CD56bri NK cells in response to EBV reactivation correlated with rapid EBV clearance post allo-HSCT in patients with younger donors. In summary, our data showed that high expression of DNAM-1 receptors on NK cell may participate protective CD56bri NK cells response to EBV infection after allo-HSCT.

Identifying an immunosenescence-associated gene signature in gastric cancer by integrating bulk and single-cell sequencing data

It has been believed that immunosenescence plays a crucial role in tumorigenesis and cancer therapy. Nevertheless, there is still a lack of understanding regarding its role in determining clinical outcomes and therapy selection for gastric cancer patients, due to the lack of a feasible immunosenescence signature. Therefore, this research aims to develop a gene signature based on immunosenescence, which is used for stratification of gastric cancer. By integrative analysis of bulk transcriptome and single-cell data, we uncovered immunosenescence features in gastric cancer. Random forest algorithm was used to select hub genes and multivariate Cox algorithm was applied to construct a scoring system to evaluate the prognosis and the response to immunotherapy and chemotherapy. The Cancer Genome Atlas of Stomach Adenocarcinoma (TCGA-STAD) cohort was implemented as the training cohort and two independent cohorts from the Gene Expression Omnibus (GEO) database were used for validation. The model was further tested by our Fudan cohort. In this study, immunosenescence was identified as a hallmark of gastric cancer that is linked with transcriptomic features, genomic variations, and distinctive tumor microenvironment (TME). Four immunosenescence genes, including APOD, ADIPOR2, BRAF, and C3, were screened out to construct a gene signature for risk stratification. Higher risk scores indicated strong predictive power for poorer overall survival. Notably, the risk score signature could reliably predict response to chemotherapy and immunotherapy, with patients with high scores benefiting from immunotherapy and patients with low scores responding to chemotherapy. We report immunosenescence as a hitherto unheralded hallmark of gastric cancer that affects prognosis and treatment efficiency.

From Genesis to Old Age: Exploring the Immune System One Cell at a Time with Flow Cytometry

The immune system is a highly complex and tightly regulated system that plays a crucial role in protecting the body against external threats, such as pathogens, and internal abnormalities, like cancer cells. It undergoes development during fetal stages and continuously learns from each encounter with pathogens, allowing it to develop immunological memory and provide a wide range of immune protection. Over time, after numerous encounters and years of functioning, the immune system can begin to show signs of erosion, which is commonly named immunosenescence. In this review, we aim to explore how the immune system responds to initial encounters with antigens and how it handles persistent stimulations throughout a person's lifetime. Our understanding of the immune system has greatly benefited from advanced technologies like flow cytometry. In this context, we will discuss the valuable contribution of flow cytometry in enhancing our knowledge of the immune system behavior in aging, with a specific focus on T-cells. Moreover, we will expand our discussion to the flow cytometry-based assessment of extracellular vesicles, a recently discovered communication channel in biology, and their implications for immune system functioning.

Immunosenescence and Inflammation in Chronic Obstructive Pulmonary Disease: A Systematic Review

Background/Objectives: Chronic Obstructive Pulmonary Disease (COPD) is a disease of premature aging, characterized by airflow limitations in the lungs and systemic chronic inflammation. This systematic review aimed to provide a systematic overview of immunosenescence and inflammation in Chronic Obstructive Pulmonary Disease (COPD). Methods: The PubMed, Science Direct, Scopus, Cochrane Library, and Web of Science databases were searched for studies on markers of immunosenescence. Observational studies comparing patients with COPD to individuals without disease were evaluated, considering the following markers: inflammation and senescence in COPD, naïve, memory, and CD28null T cells, and telomere length in leukocytes. Results: A total of 15 studies were included, eight of which were rated as high quality. IL-6 production, telomere shortening, and the higher frequencies of CD28null T cells were more prominent findings in the COPD studies analyzed. Despite lung function severity being commonly investigated in the included studies, the importance of this clinical marker to immunosenescence remains inconclusive. Conclusions: The findings of this systematic review confirmed the presence of accelerated immunosenescence, in addition to systemic inflammation, in stable COPD patients. Further studies are necessary to more comprehensively evaluate the impact of immunosenescence on lung function in COPD.

The Impact of Immune System Aging on Infectious Diseases

Immune system aging is becoming a field of increasing public health interest because of prolonged life expectancy, which is not paralleled by an increase in health expectancy. As age progresses, innate and adaptive immune systems undergo changes, which are defined, respectively, as inflammaging and immune senescence. A wealth of available data demonstrates that these two conditions are closely linked, leading to a greater vulnerability of elderly subjects to viral, bacterial, and opportunistic infections as well as lower post-vaccination protection. To face this novel scenario, an in-depth assessment of the immune players involved in this changing epidemiology is demanded regarding the individual and concerted involvement of immune cells and mediators within endogenous and exogenous factors and co-morbidities. This review provides an overall updated description of the changes affecting the aging immune system, which may be of help in understanding the underlying mechanisms associated with the main age-associated infectious diseases.

Prediction model for EBV infection following HLA haploidentical matched hematopoietic stem cell transplantation

AIMS

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is an effective treatment for hematological malignancies. However, viral infections, particularly EBV infection, frequently occur following allo-HSCT and can result in multi-tissue and organ damage. Due to the lack of effective antiviral drugs, these infections can even progress to post-transplant lymphoproliferative disorders (PTLD), thereby impacting the prognosis. In light of this, our objective is to develop a prediction model for EBV infection following allo-HSCT.

METHODS

A total of 466 patients who underwent haploidentical hematopoietic stem cell transplantation (haplo-HSCT) between September 2019 and December 2020 were included in this study. The patients were divided into a development cohort and a validation cohort based on the timing of their transplantation. Our aim was to develop and validate a grading scale using these cohorts to predict the risk of EBV infection within the first year after haplo-HSCT. Additionally, single-cell RNA sequencing (sc-RNAseq) data from the bone marrow of healthy donors were utilized to assess the impact of age on immune cells and viral infection.

RESULTS

In the multivariate logistic regression model, four predictors were retained: donor age, female-to-male transplant, graft MNC (mononuclear cell) dose, and CD8 dose. Based on these predictors, an EBV reactivation predicting score system was constructed. The scoring system demonstrated good calibration in both the derivation and validation cohorts, as confirmed by the Hosmer-Lemeshow test (p > 0.05). The scoring system also exhibited favorable discriminative ability, as indicated by the C statistics of 0.72 in the derivation cohort and 0.60 in the validation cohort. Furthermore, the clinical efficacy of the scoring system was evaluated using Kaplan-Meier curves based on risk ratings. The results showed significant differences in EBV reactivation rates between different risk groups, with p-values less than 0.001 in both the derivation and validation cohorts, indicating robust clinical utility. The analysis of sc-RNAseq data from the bone marrow of healthy donors revealed that older age had a profound impact on the quantity and quality of immune subsets. Functional enrichment analysis highlighted that older age was associated with a higher risk of infection. Specifically, CD8 + T cells from older individuals showed enrichment in the pathway of "viral carcinogenesis", while older CD14 + monocytes exhibited enrichment in the pathway of "regulation of viral entry into host cell." These findings suggest that older age may contribute to an increased susceptibility to viral infections, as evidenced by the altered immune profiles observed in the sc-RNAseq data.

CONCLUSION

Overall, these results demonstrate the development and validation of an effective scoring system for predicting EBV reactivation after haplo-HSCT, and provide insights into the impact of age on immune subsets and viral infection susceptibility based on sc-RNAseq analysis of healthy donors' bone marrow.

Association between Gut Microbiota and Biological Aging: A Two-Sample Mendelian Randomization Study

Recent observational studies revealed an association between gut microbiota and aging, but whether gut microbiota are causally associated with the aging process remains unknown. We used a two-sample Mendelian randomization approach to investigate the causal association between gut microbiota and biological age acceleration using the largest available gut microbiota GWAS summary data from the MiBioGen consortium and GWAS data on biological age acceleration. We further conducted sensitivity analysis using MR-PRESSO, MR-Egger regression, Cochran Q test, and reverse MR analysis. Streptococcus (IVW, β = 0.16, p = 0.0001) was causally associated with Bioage acceleration. Eubacterium (rectale group) (IVW, β = 0.20, p = 0.0190), Sellimonas (IVW, β = 0.06, p = 0.019), and Lachnospira (IVW, β = -0.18, p = 0.01) were suggestive of causal associations with Bioage acceleration, with the latter being protective. Actinomyces (IVW, β = 0.26, p = 0.0083), Butyricimonas (IVW, β = 0.21, p = 0.0184), and Lachnospiraceae (FCS020 group) (IVW, β = 0.24, p = 0.0194) were suggestive of causal associations with Phenoage acceleration. This Mendelian randomization study found that Streptococcus was causally associated with Bioage acceleration. Further randomized controlled trials are needed to investigate its role in the aging process.

Immune aging: biological mechanisms, clinical symptoms, and management in lung transplant recipients

While chronologic age can be precisely defined, clinical manifestations of advanced age occur in different ways and at different rates across individuals. The observed phenotype of advanced age likely reflects a superposition of several biological aging mechanisms which have gained increasing attention as the world contends with an aging population. Even within the immune system, there are multiple age-associated biological mechanisms at play, including telomere dysfunction, epigenetic dysregulation, immune senescence programs, and mitochondrial dysfunction. These biological mechanisms have associated clinical syndromes, such as telomere dysfunction leading to short telomere syndrome (STS), and optimal patient management may require recognition of biologically based aging syndromes. Within the clinical context of lung transplantation, select immune aging mechanisms are particularly pronounced. Indeed, STS is increasingly recognized as an indication for lung transplantation. At the same time, common aging phenotypes may be evoked by the stress of transplantation because lung allografts face a potent immune response, necessitating higher levels of immune suppression and associated toxicities, relative to other solid organs. Age-associated conditions exacerbated by lung transplant include bone marrow suppression, herpes viral infections, liver cirrhosis, hypogammaglobulinemia, frailty, and cancer risk. This review aims to dissect the molecular mechanisms of immune aging and describe their clinical manifestations in the context of lung transplantation. While these mechanisms are more likely to manifest in the context of lung transplantation, this mechanism-based approach to clinical syndromes of immune aging has broad relevance to geriatric medicine.

Impact of COVID-19 on immunocompromised populations during the Omicron era: insights from the observational population-based INFORM study

Background

Immunocompromised individuals are not optimally protected by COVID-19 vaccines and potentially require additional preventive interventions to mitigate the risk of severe COVID-19. We aimed to characterise and describe the risk of severe COVID-19 across immunocompromised groups as the pandemic began to transition to an endemic phase.

Methods

COVID-19-related hospitalisations, intensive care unit (ICU) admissions, and deaths (01/01/2022-31/12/2022) were compared among different groups of immunocompromised individuals vs the general population, using a retrospective cohort design and electronic health data from a random 25% sample of the English population aged ≥12 years (Registration number: ISRCTN53375662).

Findings

Overall, immunocompromised individuals accounted for 3.9% of the study population, but 22% (4585/20,910) of COVID-19 hospitalisations, 28% (125/440) of COVID-19 ICU admissions, and 24% (1145/4810) of COVID-19 deaths in 2022. Restricting to those vaccinated with ≥3 doses of COVID-19 vaccine (∼84% of immunocompromised and 51% of the general population), all immunocompromised groups remained at increased risk of severe COVID-19 outcomes, with adjusted incidence rate ratios (aIRR) for hospitalisation ranging from 1.3 to 13.1. At highest risk for COVID-19 hospitalisation were individuals with: solid organ transplant (aIRR 13.1, 95% confidence interval [95% CI] 11.2-15.3), moderate to severe primary immunodeficiency (aIRR 9.7, 95% CI 6.3-14.9), stem cell transplant (aIRR 11.0, 95% CI 6.8-17.6), and recent treatment for haematological malignancy (aIRR 10.6, 95% CI 9.5-11.9). Results were similar for COVID-19 ICU admissions and deaths.

Interpretation

Immunocompromised individuals continue to be impacted disproportionately by COVID-19 and have an urgent need for additional preventive measures beyond current vaccination programmes. These data can help determine the immunocompromised groups for which targeted prevention strategies may have the highest impact.

Funding

This study was funded by AstraZeneca UK.

Necrotizing amebic colitis in an elder patient: an unexpected autopsy finding

Necrotizing amebic colitis is an uncommon amebiasis complication associated with high mortality. We present a case of necrotizing amebic colitis in an old patient whose diagnosis was revealed at postmortem examination. An 81-year-old man died at home without medical attention. The postmortem examination revealed ulcers involving the entire colon and intestinal perforation. The ulcers were large, geographic, and necrotizing, extending from the cecum to the rectum. The histological examination disclosed the infectious etiology by showing amebic trophozoites at the base of the ulcers. No extra-intestinal lesions were found. No information about previous episodes of dysentery or travel could be obtained. The potential role of aging or drug-causing immunosuppression and the evolution of chronic and latent intestinal infection to a severe and invasive form of amebiasis is discussed. This case reinforces the value of postmortem examination for diagnosing diseases not clinically identified.

Immunomodulatory biomaterials against bacterial infections: Progress, challenges, and future perspectives

Bacterial infectious diseases are one of the leading causes of death worldwide. Even with the use of multiple antibiotic treatment strategies, 4.95 million people died from drug-resistant bacterial infections in 2019. By 2050, the number of deaths will reach 10 million annually. The increasing mortality may be partly due to bacterial heterogeneity in the infection microenvironment, such as drug-resistant bacteria, biofilms, persister cells, intracellular bacteria, and small colony variants. In addition, the complexity of the immune microenvironment at different stages of infection makes biomaterials with direct antimicrobial activity unsatisfactory for the long-term treatment of chronic bacterial infections. The increasing mortality may be partly attributed to the biomaterials failing to modulate the active antimicrobial action of immune cells. Therefore, there is an urgent need for effective alternatives to treat bacterial infections. Accordingly, the development of immunomodulatory antimicrobial biomaterials has recently received considerable interest; however, a comprehensive review of their research progress is lacking. In this review, we focus mainly on the research progress and future perspectives of immunomodulatory antimicrobial biomaterials used at different stages of infection. First, we describe the characteristics of the immune microenvironment in the acute and chronic phases of bacterial infections. Then, we highlight the immunomodulatory strategies for antimicrobial biomaterials at different stages of infection and their corresponding advantages and disadvantages. Moreover, we discuss biomaterial-mediated bacterial vaccines' potential applications and challenges for activating innate and adaptive immune memory. This review will serve as a reference for future studies to develop next-generation immunomodulatory biomaterials and accelerate their translation into clinical practice.

The role of immunosuppressive myofibroblasts in the aging process and age-related diseases

Tissue-resident fibroblasts are mesenchymal cells which control the structural integrity of the extracellular matrix (ECM). Fibroblasts possess a remarkable plasticity to allow them to adapt to the changes in the microenvironment and thus maintain tissue homeostasis. Several stresses, also those associated with the aging process, convert quiescent fibroblasts into myofibroblasts which not only display fibrogenic properties but also act as immune regulators cooperating both with tissue-resident immune cells and those immune cells recruited into affected tissues. TGF-β cytokine and reactive oxygen species (ROS) are major inducers of myofibroblast differentiation in pathological conditions either from quiescent fibroblasts or via transdifferentiation from certain other cell types, e.g., macrophages, adipocytes, pericytes, and endothelial cells. Intriguingly, TGF-β and ROS are also important signaling mediators between immunosuppressive cells, such as MDSCs, Tregs, and M2 macrophages. It seems that in pathological states, myofibroblasts are able to interact with the immunosuppressive network. There is clear evidence that a low-grade chronic inflammatory state in aging tissues is counteracted by activation of compensatory immunosuppression. Interestingly, common enhancers of the aging process, such as oxidative stress, loss of DNA integrity, and inflammatory insults, are inducers of myofibroblasts, whereas anti-aging treatments with metformin and rapamycin suppress the differentiation of myofibroblasts and thus prevent age-related tissue fibrosis. I will examine the reciprocal interactions between myofibroblasts and immunosuppressive cells within aging tissues. It seems that the differentiation of myofibroblasts with age-related harmful stresses enhances the activity of the immunosuppressive network which promotes tissue fibrosis and degeneration in elderly individuals.

From Immunosenescence to Aging Types-Establishing Reference Intervals for Immune Age Biomarkers by Centile Estimation

Immunological aging type definition requires establishing reference intervals from the distribution of immunosenescence biomarkers conditional on age. For 1605 individuals (18-97 years), we determined the comprehensive immune age index IMMAX from flow-cytometry-based blood cell sub-populations and identified age-specific centiles by fitting generalized additive models for location, scale, and shape. The centiles were uncorrelated with age and facilitated the categorization of individuals as immunologically slow or fast aging types. Using its 50th percentile as a reference, we rescaled the IMMAX to equivalent years of life (EYOL) and computed the immunological age gap as the difference between EYOL and chronological age. Applied to preliminary baseline and follow-up measurements from 53 participants of the Dortmund Vital Study (Clinical-Trials.gov Identifier: NCT05155397), the averaged changes in the IMMAX and EYOL conformed to the 5-year follow-up period, whereas no significant changes occurred concerning IMMAX centiles and age gap. This suggested that the participants immunologically adapted to aging and kept their relative positions within the cohort. Sex was non-significant. Methodical comparisons indicated that future confirmatory analyses with the completed follow-up examinations could rely on percentile curves estimated by simple linear quantile regression, while the selection of the immunosenescence biomarker will greatly influence the outcome, with IMMAX representing the preferable choice.

Changes in Interleukin-1β, Tumor Necrosis Factor-α, and Interleukin-10 Cytokines in Older People with Periodontitis

Aging can change the ability to respond to various stimuli and physical conditions. A decreased immune response is a form of deterioration of function in older people, who then become more vulnerable when exposed to pathogens. Periodontitis is an inflammatory disease of the periodontal tissues that often occurs in older people. This study aimed to clinically analyze the periodontal status and cytokine levels of IL-1β, TNF-α, and IL-10 in older people and adults with periodontitis. This clinical study examined 20 persons in a group of older people and 20 persons in a group of adults. The clinical measurements of periodontal status included the Simplified Oral Hygiene Index (OHI-S), Plaque Index (PlI), and Papilla Bleeding Index (PBI). The cytokine levels in gingival crevicular fluid (GCF) were quantified by using ELISA kits. The OHI-S, PlI, and PBI were found to be higher in the older group. The mean values of cytokines were higher in the older group than in adults, although no statistically significant differences were found. A strong correlation was found between the clinical measurements and the cytokine levels in the GCF. There was an increasing tendency of pro-inflammatory and anti-inflammatory cytokines in the older group compared to the adult group.

Driving the life course approach to vaccination through the lens of key global agendas

Globally, our population is ageing at an unprecedented rate and by 2030, which marks the end of the United Nations (UN) Decade of Healthy Ageing, the number of people aged 60 years and older will be 34% higher than today, reaching 1.4 billion. Vaccination is one of the most effective public health interventions of modern times and a key action in fostering healthy ageing throughout the life-course. To promote wellbeing at all ages, global agendas including the WHO Immunization Agenda 2030, the UN Decade of Healthy Ageing and the World Health Organization (WHO) Global Report on Ageism outline strategic actions and guidance to help implement policies and programs. Yet, the linkages between healthy ageing, functional ability and adult vaccination are not substantively recognized or integrated as cross-cutting themes, which impacts operationalization into national immunization plans. When aligned and connected strategically, these agendas have potential to substantially contribute to policy change to prioritize life-course immunization and support the preservation of function at all stages of life. This article describes the intersecting goals and visions of these strategic agendas and identifies specific elements of overlap, which when connected, could strengthen the development of comprehensive and effective national immunization policies.

Clinical evidence of human pathogens implicated in Alzheimer's disease pathology and the therapeutic efficacy of antimicrobials: an overview

A wealth of pre-clinical reports and data derived from human subjects and brain autopsies suggest that microbial infections are relevant to Alzheimer's disease (AD). This has inspired the hypothesis that microbial infections increase the risk or even trigger the onset of AD. Multiple models have been developed to explain the increase in pathogenic microbes in AD patients. Although this hypothesis is well accepted in the field, it is not yet clear whether microbial neuroinvasion is a cause of AD or a consequence of the pathological changes experienced by the demented brain. Along the same line, the gut microbiome has also been proposed as a modulator of AD. In this review, we focus on human-based evidence demonstrating the elevated abundance of microbes and microbe-derived molecules in AD hosts as well as their interactions with AD hallmarks. Further, the direct-purpose and potential off-target effects underpinning the efficacy of anti-microbial treatments in AD are also addressed.

Nutraceuticals as Modulators of Immune Function: A Review of Potential Therapeutic Effects

Dietary supplementation with nutraceuticals can promote optimal immune system activation, modulating different pathways that enhance immune defenses. Therefore, the immunity-boosting effects of nutraceuticals encompass not only immunomodulatory but also antioxidant, antitumor, antiviral, antibacterial, and antifungal properties, with therapeutic effects against diverse pathological conditions. However, the complexity of the pathways that regulate the immune system, numerous mechanisms of action, and heterogeneity of the immunodeficiencies, and subjects treated make their application in the clinical field difficult. Some nutraceuticals appear to safely improve immune system function, particularly by preventing viral and bacterial infections in specific groups, such as children, the elderly, and athletes, as well as in frail patients, such as those affected by autoimmune diseases, chronic diseases, or cancer. Several nutraceuticals, such as vitamins, mineral salts, polyunsaturated omega-3 fatty acids, many types of phytocompounds, and probiotic strains, have the most consolidated evidence in humans. In most cases, further large and long-term randomized clinical trials are needed to confirm the available preliminary positive data.

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.

Senotherapeutics: An emerging approach to the treatment of viral infectious diseases in the elderly

In the context of the global COVID-19 pandemic, the phenomenon that the elderly have higher morbidity and mortality is of great concern. Existing evidence suggests that senescence and viral infection interact with each other. Viral infection can lead to the aggravation of senescence through multiple pathways, while virus-induced senescence combined with existing senescence in the elderly aggravates the severity of viral infections and promotes excessive age-related inflammation and multiple organ damage or dysfunction, ultimately resulting in higher mortality. The underlying mechanisms may involve mitochondrial dysfunction, abnormal activation of the cGAS-STING pathway and NLRP3 inflammasome, the role of pre-activated macrophages and over-recruited immune cells, and accumulation of immune cells with trained immunity. Thus, senescence-targeted drugs were shown to have positive effects on the treatment of viral infectious diseases in the elderly, which has received great attention and extensive research. Therefore, this review focused on the relationship between senescence and viral infection, as well as the significance of senotherapeutics for the treatment of viral infectious diseases.

Sex-disaggregated outcomes of adverse events after COVID-19 vaccination: A Dutch cohort study and review of the literature

Background

Albeit the need for sex-disaggregated results of adverse events after immunization (AEFIs) is gaining attention since the COVID-19 pandemic, studies with emphasis on sexual dimorphism in response to COVID-19 vaccination are relatively scarce. This prospective cohort study aimed to assess differences in the incidence and course of reported AEFIs after COVID-19 vaccination between males and females in the Netherlands and provides a summary of sex-disaggregated outcomes in published literature.

Methods

Patient reported outcomes of AEFIs over a six month period following the first vaccination with BioNTech-Pfizer, AstraZeneca, Moderna or the Johnson&Johnson vaccine were collected in a Cohort Event Monitoring study. Logistic regression was used to assess differences in incidence of 'any AEFI', local reactions and the top ten most reported AEFIs between the sexes. Effects of age, vaccine brand, comorbidities, prior COVID-19 infection and the use of antipyretic drugs were analyzed as well. Also, time-to-onset, time-to-recovery and perceived burden of AEFIs was compared between the sexes. Third, a literature review was done to retrieve sex-disaggregated outcomes of COVID-19 vaccination.

Results

The cohort included 27,540 vaccinees (38.5% males). Females showed around two-fold higher odds of having any AEFI as compared to males with most pronounced differences after the first dose and for nausea and injection site inflammation. Age was inversely associated with AEFI incidence, whereas a prior COVID-19 infection, the use of antipyretic drugs and several comorbidities were positively associated. The perceived burden of AEFIs and time-to-recovery were slightly higher in females.

Discussion

The results of this large cohort study correspond to existing evidence and contribute to the knowledge gain necessary to disentangle the magnitude of the effect sex in response to vaccination. Whilst females have a significant higher probability of experiencing an AEFI than males, we observed that the course and burden is only to a minor extent different between the sexes.

Emerging cellular senescence-centric understanding of immunological aging and its potential modulation through dietary bioactive components

Immunological aging is strongly associated with the observable deleterious effects of human aging. Our understanding of the causes, effects, and therapeutics of aging immune cells has long been considered within the sole purview of immunosenescence. However, it is being progressively realized that immunosenescence may not be the only determinant of immunological aging. The cellular senescence-centric theory of aging proposes a more fundamental and specific role of immune cells in regulating senescent cell (SC) burden in aging tissues that has augmented the notion of senescence immunotherapy. Now, in addition, several emerging studies are suggesting that cellular senescence itself may be prevalent in aging immune cells, and that senescent immune cells exhibiting characteristic markers of cellular senescence, similar to non-leucocyte cells, could be among the key drivers of various facets of physiological aging. The present review integrates the current knowledge related to immunosenescence and cellular senescence in immune cells per se, and aims at providing a cohesive overview of these two phenomena and their significance in immunity and aging. We present evidence and rationalize that understanding the extent and impact of cellular senescence in immune cells vis-à-vis immunosenescence is necessary for truly comprehending the notion of an 'aged immune cell'. In addition, we also discuss the emerging significance of dietary factors such as phytochemicals, probiotic bacteria, fatty acids, and micronutrients as possible modulators of immunosenescence and cellular senescence. Evidence and opportunities related to nutritional bioactive components and immunological aging have been deliberated to augment potential nutrition-oriented immunotherapy during aging.

Upregulation of p16INK4A in Peripheral White Blood Cells as a Novel Screening Marker for Colorectal Carcinoma

OBJECTIVE

Screening of colorectal cancer (CRC) is important for the early detection. CRC is relating to aging and immuno-senescence. One such senescent marker is p16INK4A expression in immune cells. The objective of the study is to investigate the protein expression of p16INK4A in peripheral white blood cells as a screening marker for colorectal cancer.

METHODS

A case-control studies were conducted. Cases were patients with colorectal cancer and controls were matched with cases based on age and sex. Peripheral blood was collected from patients and controls and the protein p16INK4A was measured with immunofluorescent techniques. The p16INK4A levels from cases and controls were evaluated using ROC analysis to be used as a screening marker in CRC patients. Mean fluorescent intensity of p16INK4A of cases and controls were analyzed in CD45+, CD3+ or CD14+ cells. The p16INK4A levels of cases were also correlated with clinical data.

RESULT

Statistically significant increased expression of p16INK4A levels were found in cases compared to controls. p16INK4A in peripheral immune cells had 78% sensitivity and 71% specificity which can possibly be used as a diagnosis tool for colorectal cancer. P16INK4A-positive cell percentage and mean florescent intensity were significantly higher in CD45+ cells, CD3 positive cells and CD14 positive cells. No significant correlation was observed with the clinical data and p16INK4A level of CRC patients.

CONCLUSION

The significant increase of p16 INK4A expression level in peripheral immune cells represents potential for use as a CRC screening marker.

Calibrating a Comprehensive Immune Age Metric to Analyze the Cross Sectional Age-Related Decline in Cardiorespiratory Fitness

Cardiorespiratory fitness (CRF) is essential for sustained work ability in good health, but declines with aging, as does the functionality of the immune system, the latter process commonly referred to as immunosenescence. This study aimed to compare the capacity of immunosenescence biomarkers with chronological age for predicting low CRF in a cross-sectional sample recruited from the regional working population. CRF was determined by submaximal bicycle ergometer testing in a cross-sectional sample of 597 volunteers aged 20-70 years from the 'Dortmund Vital Study' (DVS, ClinicalTrials.gov Identifier: NCT05155397). Low CRF was scored if the ergometer test was not completed due to medical reasons or if the power output projected to a heart rate of 130 bpm divided by body mass was below sex-specific reference values of 1.25 W/kg for females and 1.5 W/kg for males, respectively. In addition to established biomarkers of immunosenescence, we calibrated a comprehensive metric of immune age to our data and compared its predictive capacity for low CRF to chronological age, while adjusting our analysis for the influence of sex, obesity, and the level of regular physical activity, by applying univariate and multiple logistic regression. While obesity, low physical activity, chronological and immune age were all associated with increased probability for low CRF in univariate analyses, multiple logistic regression revealed that obesity and physical activity together with immune age, but not chronological age, were statistically significant predictors of low CRF outcome. Sex was non-significant due to the applied sex-specific reference values. These results demonstrate that biological age assessed by our immunological metric can outperform chronological age as a predictor for CRF and indicate a potential role for immunosenescence in explaining the inter-individual variability of the age-related decline in cardiorespiratory fitness.

The ABC-associated Immunosenescence and Lifestyle Interventions in Autoimmune Disease

Aging-associated immune changes, termed immunosenescence, occur with impaired robust immune responses. This immune response is closely related to a greater risk of development of autoimmune disease (AID), which results in increased levels of autoantibodies and increased morbidity and mortality. In addition, lifestyle-related risk factors play a pivotal role in AID, which may be probable via senescence-related immune cell subsets. Age-associated B cell (ABC) subsets have been observed in those who have rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and multiple sclerosis (MS). Here, this review aims to highlight the mechanisms of ABCs with lifestyle interventions in AID, especially how immunosenescence affects the pathogenesis of AID and the future of aging-associated lifestyle interventions in immunosenescence of AID.

Ross J, Scott Herron G. Genetic and Epigenetic Influences on Cutaneous Cellular Senescence

Skin is the largest human organ system, and its protective function is critical to survival. The epithelial, dermal, and subcutaneous compartments are heterogeneous mixtures of cell types, yet they all display age-related skin dysfunction through the accumulation of an altered phenotypic cellular state called senescence. Cellular senescence is triggered by complex and dynamic genetic and epigenetic processes. A senescence steady state is achieved in different cell types under various and overlapping conditions of chronological age, toxic injury, oxidative stress, replicative exhaustion, DNA damage, metabolic dysfunction, and chromosomal structural changes. These inputs lead to outputs of cell-cycle withdrawal and the appearance of a senescence-associated secretory phenotype, both of which accumulate as tissue pathology observed clinically in aged skin. This review details the influence of genetic and epigenetic factors that converge on normal cutaneous cellular processes to create the senescent state, thereby dictating the response of the skin to the forces of both intrinsic and extrinsic aging. From this work, it is clear that no single biomarker or process leads to senescence, but that it is a convergence of factors resulting in an overt aging phenotype.

Observed protection against SARS-CoV-2 reinfection following a primary infection: A Danish cohort study among unvaccinated using two years of nationwide PCR-test data

Background

The level of protection after a SARS-CoV-2 infection against reinfection and COVID-19 disease remains important with much of the world still unvaccinated.

Methods

Analysing nationwide, individually referable, Danish register data including RT-PCR-test results, we conducted a cohort study using Cox regression to compare SARS-CoV-2 infection rates before and after a primary infection among still unvaccinated individuals, adjusting for sex, age, comorbidity and residency region. Estimates of protection against infection were calculated as 1 minus the hazard ratio. Estimates of protection against symptomatic infections and infections leading to hospitalisation were also calculated. The prevalence of infections classified as symptomatic or asymptomatic was compared for primary infections and reinfections. The study also assessed protection against each of the main viral variants after a primary infection with an earlier variant by restricting follow-up time to distinct, mutually exclusive periods during which each variant dominated.

Findings

Until 1 July 2021 the estimated protection against reinfection was 83.4% (95%CI: 82.2-84.6%); but lower for the 65+ year-olds (72.2%; 95%CI: 53.2-81.0%). Moderately higher estimates were found for protection against symptomatic disease, 88.3% overall (95%CI: 85.9-90.3%). First-time cases who reported no symptoms were more likely to experience a reinfection (odds ratio: 1.48; 95%CI: 1.35-1.62). By autumn 2021, when infections were almost exclusively caused by the Delta variant, the estimated protection following a recent first infection was 91.3% (95%CI: 89.7-92.7%) compared to 71.4% (95%CI: 66.9-75.3%) after a first infection over a year earlier. With Omicron, a first infection with an earlier variant in the past 3-6 months gave an estimated 51.0% (95%CI: 50.1-52.0%) protection, whereas a first infection longer than 12 months earlier provided only 19.0% (95%CI: 17.2-20.5%) protection. Protection by an earlier variant-infection against hospitalisation due to a new infection was estimated at: 86.6% (95%CI: 46.3-96.7%) for Alpha, 97.2% (95%CI: 89.0-99.3%) for Delta, and 69.8% (95%CI: 51.5-81.2%) for the Omicron variant.

Interpretation

SARS-CoV-2 infection offered a high level of sustained protection against reinfection, comparable with that offered by vaccines, but decreased with the introduction of new main virus variants; dramatically so when Omicron appeared. Protection was lower among the elderly but appeared more pronounced following symptomatic compared to asymptomatic infections. The level of estimated protection against serious disease was somewhat higher than that against infection and possibly longer lasting. Decreases in protection against reinfection, seemed primarily to be driven by viral evolution.

Funding

None.

Circulating Extracellular Vesicles and Particles Derived From Adipocytes: The Potential Role in Spreading MicroRNAs Associated With Cellular Senescence

Aging is associated with adipose tissue dysfunction and is recognized as a risk factor for shortened life span. Considering that in vitro findings have shown the involvement of microRNA in extracellular vesicles and particles (EVPs) on senescence, we hypothesized that circulating EVPs derived from adipocytes can be involved in the aging process via their microRNA cargo. We aimed to determine the microRNA profiles of circulating EVPs derived from adipocytes (FABP4+) from aged and young adult animals and to perform in silico prediction of their downstream signaling effects. Plasma was obtained from Wistar rats (3 and 21 months old), and adipocyte-derived EVPs were isolated using the commercially available kit. Fatty acid-binding protein 4 (FABP4) was used for adipocyte-derived EVPs isolation; microRNA isolation and microarray expression analysis were performed. The analysis revealed 728 miRNAs, 32 were differentially between groups (p &lt; 0.05; fold change ≥ |1.1|), of which 15 miRNAs were upregulated and 17 were downregulated in circulating EVPs from aged animals compared to young adults. A conservative filter was applied, and 18 microRNAs had experimentally validated and highly conserved predicted mRNA targets, with a total of 2,228 mRNAs. Canonical pathways, disease and functions, and upstream regulator analyses were performed using IPA-QIAGEN, allowing a global and interconnected evaluation. IPA categories impacted negatively were cell cycle, cellular development, cellular growth and proliferation, and tissue development, while those impacted positively were “digestive system cancer” and “endocrine gland tumor.” Interestingly, the upregulated miR-15-5p targets several cyclins, such as CCND1 and CCND2, and miR-24-3p seems to target CDK4 (cyclin-dependent kinase 4); then potentially inhibiting their expression, both miRNAs can induce a negative regulation of cell cycle progression. In contrast, silencing of negative cell cycle checkpoint regulators, such as p21 and p16, can be predicted, which can induce impairment in response to genotoxic stressors. In addition, predicted targets, such as SMAD family members, seem to be involved in the positive control of digestive and endocrine tumors. Taken together, this exploratory study indicates that miRNA signature in circulating adipocyte-derived EVPs may be involved with the double-edged sword of cellular senescence, including irreversible proliferation arrest and tissue-dependent cancer, and seems to be suitable for further validation and confirmatory studies.

Characterisation of the immune microenvironment of cutaneous squamous cell carcinoma in immunosuppression

Cutaneous squamous cell carcinoma (cSCC) is a common cancer. Systemic immunosuppression with drugs such as Prednisone results in more aggressive disease. We hypothesise that more aggressive disease in immunosuppression is the result of immune changes in the tumour microenvironment. We characterised T cell, phagocytic and antigen presenting cell subsets in cSCC, and determined if these infiltrates were altered by immunosuppressive therapy. We found a dominant 'CD8 profile' in the centre of cSCC lesions, with CD8 cells correlating with Tbet, FoxP3, OX40 and 'M2-like' macrophages, whereas a 'Tbet and granulocyte profile' with associated inflammation predominated at the margin of the tumour. Individuals on systemic immunosuppressive therapy had lesions that were comparable in size, stage and number of vessels to immune competent individuals however the number of CD11c positive cells in the lesion centre was significantly reduced. We conclude that cSCC lesions are immunologically heterogeneous across the lesion and that systemically immunosuppressed individuals have reduced CD11c positive cells in the centre of the lesion. The role and detailed phenotype of CD11c positive cells in cSCC lesions warrants further investigation.

Nicotinamide mononucleotide supplementation protects the intestinal function in aging mice and D-galactose induced senescent cells

The nicotinamide adenine dinucleotide (NAD⁺) level shows a temporal decrease during the aging process, which has been deemed as an aging hallmark. Nicotinamide mononucleotide (NMN), a key NAD⁺ precursor, shows the potential to retard the age-associated functional decline in organs. In the current study, to explore whether NMN has an impact on the intestine during the aging process, the effects of NMN supplementation on the intestinal morphology, microbiota, and NAD⁺ content, as well as its anti-inflammatory, anti-oxidative and barrier functions were investigated in aging mice and D-galactose (D-gal) induced senescent IPEC-J2 cells. The results showed that 4 months of NMN administration had little impact on the colonic microbiota and NAD⁺ content in aging mice, while it significantly increased the jejunal NAD⁺ content and improved the jejunal structure including increasing the villus length and shortening the crypt. Moreover, NMN supplementation significantly up-regulated the mRNA expression of SIRT3, SIRT6, nuclear factor E2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), the catalytic subunit of glutamate-cysteine ligase (GCLC), superoxide dismutase 2 (SOD2), occludin, and claudin-1, but down-regulated the mRNA expression of tumor necrosis factor alpha (TNF-α). Specifically, in the D-gal induced senescent IPEC-J2 cells, 500 μM NMN restored the increased mRNA expression of interleukin 6 (IL6ST), IL-1A, nuclear factor (NF-κB1), and claudin-1 to normal levels to some extent. Furthermore, NMN treatment significantly affected the mRNA expression of antioxidant enzymes including NQO1, GCLC, SOD 2 and 3, and GSH-PX1, 3 and 4. In addition, 200 μM NMN enhanced the cell viability and total antioxidant capacity and lowered the reactive oxygen species level of senescent IPEC-J2 cells. Notably, NMN restored the down-regulated protein expression of occludin and claudin-1 induced by D-gal. The above data demonstrated the potential of NMN in ameliorating the structural and functional decline in the intestine during aging.

Cellular Immunity Is Critical for Assessing COVID-19 Vaccine Effectiveness in Immunocompromised Individuals

COVID-19 vaccine clinical development was conducted with unprecedented speed. Immunity measurements were concentrated on the antibody response which left significant gaps in our understanding how robust and long-lasting immune protection develops. Better understanding the cellular immune response will fill those gaps, especially in the elderly and immunocompromised populations which not only have the highest risk for severe infection, but also frequently have inadequate antibody responses. Although cellular immunity measurements are more logistically complex to conduct for clinical trials compared to antibody measurements, the feasibility and benefit of doing them in clinical trials has been demonstrated and so should be more widely adopted. Adding significant cellular response metrics will provide a deeper understanding of the overall immune response to COVID-19 vaccination, which will significantly inform vaccination strategies for the most vulnerable populations. Better monitoring of overall immunity will also substantially benefit other vaccine development efforts, and indeed any therapies that involve the immune system as part of the therapeutic strategy.

Estrogen, the Peripheral Immune System and Major Depression – A Reproductive Lifespan Perspective

Major depression is a significant medical issue impacting millions of individuals worldwide. Identifying factors contributing to its manifestation has been a subject of intense investigation for decades and several targets have emerged including sex hormones and the immune system. Indeed, an extensive body of literature has demonstrated that sex hormones play a critical role in modulating brain function and impacting mental health, especially among female organisms. Emerging findings also indicate an inflammatory etiology of major depression, revealing new opportunities to supplement, or even supersede, currently available pharmacological interventions in some patient populations. Given the established sex differences in immunity and the profound impact of fluctuations of sex hormone levels on the immune system within the female, interrogating how the endocrine, nervous, and immune systems converge to impact women’s mental health is warranted. Here, we review the impacts of endogenous estrogens as well as exogenously administered estrogen-containing therapies on affect and immunity and discuss these observations in the context of distinct reproductive milestones across the female lifespan. A theoretical framework and important considerations for additional study in regards to mental health and major depression are provided.

Immunosenescence and Altered Vaccine Efficiency in Older Subjects: A Myth Difficult to Change

Organismal ageing is associated with many physiological changes, including differences in the immune system of most animals. These differences are often considered to be a key cause of age-associated diseases as well as decreased vaccine responses in humans. The most often cited vaccine failure is seasonal influenza, but, while it is usually the case that the efficiency of this vaccine is lower in older than younger adults, this is not always true, and the reasons for the differential responses are manifold. Undoubtedly, changes in the innate and adaptive immune response with ageing are associated with failure to respond to the influenza vaccine, but the cause is unclear. Moreover, recent advances in vaccine formulations and adjuvants, as well as in our understanding of immune changes with ageing, have contributed to the development of vaccines, such as those against herpes zoster and SARS-CoV-2, that can protect against serious disease in older adults just as well as in younger people. In the present article, we discuss the reasons why it is a myth that vaccines inevitably protect less well in older individuals, and that vaccines represent one of the most powerful means to protect the health and ensure the quality of life of older adults.

Dysfunctional telomeres through mitostress-induced cGAS/STING activation to aggravate immune senescence and viral pneumonia

Disproportionately high incidence and mortality of respiratory infection such as influenza A virus (IAV) and SARS-CoV-2 have been evidenced in the elderly, but the role and the mechanism of age-associated immune deregulation in disease exacerbation are not well defined. Using a late generation of mice deficient in telomerase RNA (Terc^-/- ), we herein demonstrated that aged mice were exquisitely susceptible to respiratory viral infection, with excessive inflammation and increased mortality. Furthermore, we identified the cGAS/STING pathway, which was essentially induced by the leaked mitochondrial DNA, as a biologically relevant mechanism contributing to exaggerated inflammation in Terc^-/- mice following viral infection. Innate immune cells, mainly, macrophages with shortened telomeres, exhibited hallmarks of cellular senescence, mitochondrial distress, and aberrant activation of STING and NLRP3 inflammasome pathways, which predisposed mice to severe viral pneumonia during commonly mild infections. Application of STING inhibitor and, more importantly, senolytic agent, reduced the burden of stressed macrophages, improved mitochondrial integrity, and suppressed STING activation, thereby conferring the protection for Terc^-/- mice against respiratory infection. Together, the findings expand our understanding of innate immune senescence and reveal the potential of the senolytics as a promising treatment to alleviate the symptom of viral pneumonia, particularly for the older population.

Community-acquired bacterial meningitis in patients of 80 years and older

Background

Advanced age is a risk factor for unfavorable outcome in community‐acquired bacterial meningitis, but clinical characteristics and outcome in meningitis patients of 80 years or older have not been defined.

Methods

We compared clinical characteristics and outcome of community‐acquired bacterial meningitis patients aged 80 years or older and adults under 80 years old within a prospective nationwide cohort study.

Results

Out of 2140 episodes identified between March 2006 and July 2018, 149 occurred in patients aged 80 years or older (7%). Common predisposing factors other than age were diabetes mellitus (25 of 148 [17%]), otitis or sinusitis (30 of 136 [22%]), and pneumonia (23 of 141 [16%]). The triad of fever, neck stiffness and altered consciousness was present in 60 of 139 (43%). The most common causative pathogen was Streptococcus pneumoniae (99 of 149 [66%]). Atypical causative pathogens, such as Listeria monocytogenes, Staphylococcus aureus, and Escherichia coli, occurred more often compared to younger patients (49 of 149 [33%] vs 362 of 1991 [18%]; p < 0.001). Patients of 80 years and older had high case fatality rate (75 of 149 [50%]), but 45 of 149 (30%) had a favorable outcome. Characteristics associated with an unfavorable outcome were absence of otitis or sinusitis, presence of aphasia, mono‐ or hemiparesis, a lower score on the Glasgow Coma Scale, a higher heart rate, a higher blood C‐reactive protein concentration and CSF leukocytes <100 per mm³.

Conclusions

Bacterial meningitis in patients of 80 years of older is associated with high rates of unfavorable outcome and death. Atypical causative pathogens such as L. monocytogenes, S. aureus, and E. coli occur commonly and should be considered when starting empirical antimicrobial therapy in this age group.

Evaluation of central venous catheter and other risk factors for mortality in chronic hemodialysis patients with COVID-19 in Brazil

PURPOSE

Hemodialysis patients with COVID-19 are at increased risk of death. We aimed to describe the characteristics of a cohort of Brazilian hemodialysis patients with COVID-19 and assess their mortality rate and risk factors for death.

METHODS

Retrospective cohort study of 741 Brazilian hemodialysis patients with confirmed COVID-19 from Feb-Dec/2020, of 52 dialysis centers of the country. We analyzed comorbid conditions, sociodemographic factors, and dialysis-related parameters. To detect risk factors for mortality in hemodialysis patients, we performed multivariable Cox proportional hazard regression analysis. Survival was analyzed by Kaplan-Meier.

RESULTS

From 9877 hemodialysis patients, 741 were diagnosed with COVID-19. Mean age was 57 ± 16 years, 61% were male, and 51% white. The most frequent symptoms were fever (54.1%), cough (50.9%), and dyspnea (37.2%); 14.2% were asymptomatic. There were 139 deaths (18.8%), with 66% within the disease's first 15 days. 333 patients (44.9%) required hospitalization, and 211 (28.5%) were admitted to an intensive care unit. The cumulative probability of survival at 90 days of diagnosis was 79% (95% CI 76-82%). In the fully adjusted multivariate model, the risk factors significantly associated with death were diabetes mellitus (HR 1.52, 95% CI 1.05-2.19, P = 0.026), use of a central venous catheter (CVC) (HR 1.79, 95% CI 1.22-2.64, P = 0.003), age (HR 1.03, 95% CI 1.01-1.04, P < 0.001), and origin from the North vs. Southeast region (HR 2.60, 95% CI 1.01-6.68, P = 0.047).

CONCLUSIONS

Hemodialysis patients using a CVC as the vascular access, aside from diabetic and elderly ones, should be closely monitored due to their high risk of death in the course of the COVID-19.

The Potential Role of miRNAs in Cognitive Frailty

Frailty is an aging related condition, which has been defined as a state of enhanced vulnerability to stressors, leading to a limited capacity to meet homeostatic demands. Cognitive impairment is also frequent in older people, often accompanying frailty. Age is the main independent risk factor for both frailty and cognitive impairment, and compelling evidence suggests that similar age-associated mechanisms could underlie both clinical conditions. Accordingly, it has been suggested that frailty and cognitive impairment share common pathways, and some authors proposed "cognitive frailty" as a single complex phenotype. Nevertheless, so far, no clear common underlying pathways have been discovered for both conditions. microRNAs (miRNAs) have emerged as key fine-tuning regulators in most physiological processes, as well as pathological conditions. Importantly, miRNAs have been proposed as both peripheral biomarkers and potential molecular factors involved in physiological and pathological aging. In this review, we discuss the evidence linking changes of selected miRNAs expression with frailty and cognitive impairment. Overall, miR-92a-5p and miR-532-5p, as well as other miRNAs implicated in pathological aging, should be investigated as potential biomarkers (and putative molecular effectors) of cognitive frailty.

Association between Body Mass Index and Immune-Related Adverse Events (irAEs) among Advanced-Stage Cancer Patients Receiving Immune Checkpoint Inhibitors: A Pan-Cancer Analysis

Simple Summary

Currently, clinical studies exploring the impact of high body fat on toxicities after receiving immune checkpoint inhibitors (ICIs) among cancer patients are limited. Here, we analyze data from a health care system serving the mid-Atlantic geographic region to assess how body fat can affect the development of toxicities of ICIs. In our study, body mass index (BMI) was used as the measure of body fat, and the results suggested that cancer patients with a high BMI were more likely to have toxicities after receiving ICIs. Our study suggests that symptom management should be incorporated in the cancer care continuum of patients who receive ICIs, especially those with high BMI. In clinical settings, oncologists should inform cancer patients receiving ICIs with high BMI that their risk of post-treatment toxicities can be higher compared to their counterparts with lower BMI.

Abstract

Evidence regarding the association between body mass index (BMI) and immune-related adverse events (irAEs) among cancer patients receiving immune checkpoint inhibitors (ICIs) is limited. Here, we use cross-sectional hospital-based data to explore their relationship. Pre-treatment BMI was treated as an ordinal variable (<25, 25 to ≤30, ≥30 kg/m²). The outcome of interest was irAEs after ICI initiation. A multivariable logistic regression model estimated the adjusted odds ratio (aOR) and 95% confidence interval (CI) of BMI. A total of 684 patients with stage III or IV cancer were included in the study (lung: 269, melanoma: 204, other: 211). The mean age at the first dose of ICI was 64.1 years (SD = 13.5), 394 patients (57.6%) were male, and over one-third (N = 260, 38.0%) were non-White. Overall, 52.9% of patients had BMI ≥ 25 kg/m² (25 to ≤30: 217, ≥30: 145) and 288 (42.1%) had irAEs after ICI treatment. Patients with higher BMI tended to have a higher rate of irAEs (<25: 35.7%, 25 to ≤30: 47.0%, ≥30: 49.0%). The multivariable logistic regression yielded consistent results (BMI ≥ 30 vs. BMI < 25: aOR = 1.47, 95% CI = 0.96–2.23; 25 ≤ BMI < 30 vs. BMI < 25: aOR = 1.46, 95% CI = 1.02–2.11, p-trend = 0.04). In conclusion, among patients with advanced cancer receiving ICIs, the rate of irAEs appears to be higher among those with higher BMI.