Inflammaging as a target for healthy ageing

The RESIST Senior Individuals Cohort: Design, participant characteristics and aims

The number of older adults worldwide is growing exponentially. However, while living longer, older individuals are more susceptible to both non-infectious and infectious diseases, at least in part due to alterations of the immune system. Here, we report on a prospective cohort study investigating the influence of age on immune responses and susceptibility to infection. The RESIST Senior Individuals (SI) cohort was established as a general population cohort with a focus on the elderly, enrolling an age- and sex-stratified sample of 650 individuals (n = 100 20-39y, n = 550 61-94y, 2019-2023, Hannover, Germany). It includes clinical, demographic, and lifestyle data and also extensive biomaterial sampling. Initial insights indicate that the SI cohort exhibits characteristics of the aging immune system and the associated susceptibility to infection, thereby providing a suitable platform for the decoding of age-related alterations of the immune system and unraveling the molecular mechanisms underlying the impaired immune responsiveness in aging populations by exploring comprehensive, unbiased multi-omics datasets.

Cellular senescence and sleep in childhood and adolescence: A scoping review focusing on sleep-disordered breathing

BACKGROUND

Sleep is a fundamental and complex physiological process whose duration decreases and characteristics change with age. Around 50 % of children will experience sleep disturbances at some point in their early life. Sleep disturbances can result in a number of deleterious consequences, including alterations in the levels of cellular senescence (CS) markers. CS is a complex process essential for homeostasis characterized by the irreversible loss of cell proliferation capacity; however, the accumulation of senescent cells can lead to age-related diseases.

OBJECTIVE

In this review, our objective was to gather information about the relationship between sleep duration, sleep-disordered breathing (SDB) and cellular senescence markers, namely: oxidative stress, inflammation, insulin-like growth factor 1 (IGF-1), and growth hormone (GH) in newborns, children, and teenagers.

METHODS

To achieve this, we searched six databases: MEDLINE, Scopus, LILACS, Web of Science, Embase, and SciELO, and identified 20 articles that met our inclusion criteria.

RESULTS

Our results show that better sleep quality and duration and, both the surgical and non-surgical treatment of sleep disorders are associated with a reduction in oxidative stress, inflammation, and telomeric attrition levels. Furthermore, our results also show that surgical treatment for SDB significantly reduced the levels of cellular senescence markers. Further studies need to be conducted in this area, particularly longitudinal studies, for a greater understanding of the mechanisms involved in the relationship between sleep and senescence.

CONCLUSION

Better sleep quality and duration were associated with less oxidative stress, inflammation, and telomeric attrition and a higher level of IGF-1 in children and teenagers.

Identification of crosstalk genes and immune characteristics between Alzheimer's disease and atherosclerosis

Background

Advancements in modern medicine have extended human lifespan, but they have also led to an increase in age-related diseases such as Alzheimer's disease (AD) and atherosclerosis (AS). Growing research evidence indicates a close connection between these two conditions.

Methods

We downloaded four gene expression datasets related to AD and AS from the Gene Expression Omnibus (GEO) database (GSE33000, GSE100927, GSE44770, and GSE43292) and performed differential gene expression (DEGs) analysis using the R package "limma". Through Weighted gene correlation network analysis (WGCNA), we selected the gene modules most relevant to the diseases and intersected them with the DEGs to identify crosstalk genes (CGs) between AD and AS. Subsequently, we conducted functional enrichment analysis of the CGs using DAVID. To screen for potential diagnostic genes, we applied the least absolute shrinkage and selection operator (LASSO) regression and constructed a logistic regression model for disease prediction. We established a protein-protein interaction (PPI) network using STRING (https://cn.string-db.org/) and Cytoscape and analyzed immune cell infiltration using the CIBERSORT algorithm. Additionally, NetworkAnalyst (http://www.networkanalyst.ca) was utilized for gene regulation and interaction analysis, and consensus clustering was employed to determine disease subtypes. All statistical analyses and visualizations were performed using various R packages, with a significance level set at p<0.05.

Results

Through intersection analysis of disease-associated gene modules identified by DEGs and WGCNA, we identified a total of 31 CGs co-existing between AD and AS, with their biological functions primarily associated with immune pathways. LASSO analysis helped us identify three genes (C1QA, MT1M, and RAMP1) as optimal diagnostic CGs for AD and AS. Based on this, we constructed predictive models for both diseases, whose accuracy was validated by external databases. By establishing a PPI network and employing four topological algorithms, we identified four hub genes (C1QB, CSF1R, TYROBP, and FCER1G) within the CGs, closely related to immune cell infiltration. NetworkAnalyst further revealed the regulatory networks of these hub genes. Finally, defining C1 and C2 subtypes for AD and AS respectively based on the expression profiles of CGs, we found the C2 subtype exhibited immune overactivation.

Conclusion

This study utilized gene expression matrices and various algorithms to explore the potential links between AD and AS. The identification of CGs revealed interactions between these two diseases, with immune and inflammatory imbalances playing crucial roles in their onset and progression. We hope these findings will provide valuable insights for future research on AD and AS.

Postbiotics as Molecules Targeting Cellular Events of Aging Brain-The Role in Pathogenesis, Prophylaxis and Treatment of Neurodegenerative Diseases

Aging is the most prominent risk factor for neurodegeneration occurrence. The most common neurodegenerative diseases (NDs), Alzheimer's (AD) and Parkinson's (PD) diseases, are characterized by the incidence of proteinopathy, abnormal activation of glial cells, oxidative stress, neuroinflammation, impaired autophagy and cellular senescence excessive for the patient's age. Moreover, mitochondrial disfunction, epigenetic alterations and neurogenesis inhibition, together with increased blood-brain barrier permeability and gut dysbiosis, have been linked to ND pathogenesis. Since NDs still lack curative treatment, recent research has sought therapeutic options in restoring gut microbiota and supplementing probiotic bacteria-derived metabolites with beneficial action to the host-so called postbiotics. The current review focuses on literature explaining cellular mechanisms involved in ND pathogenesis and research addressing the impact that postbiotics as a whole mixture and particular metabolites, such as short-chain fatty acids (SCFAs), lactate, polyamines, polyphenols, tryptophan metabolites, exopolysaccharides and bacterial extracellular vesicles, have on the ageing-associated processes underlying ND occurrence. The review also discusses the issue of implementing postbiotics into ND prophylaxis and therapy, depicting them as compounds addressing senescence-triggered dysfunctions that are worth translating from bench to pharmaceutical market in response to "silver consumers" demands.

Ultraprocessed foods, unprocessed or minimally processed foods, and risk of frailty in a cohort of United States females

BACKGROUND

Ultraprocessed foods (UPFs) and poor diet quality have been associated with frailty but existing studies had relatively short follow-up time. It is also unclear whether the association of UPF was primarily due to its correlation with poorer diet quality.

OBJECTIVES

We examined the association between unprocessed or minimally processed foods (UMFs) and UPF and risk of frailty and explored whether the association with UPF was mainly driven by poor diet quality.

METHODS

In total, 63,743 nonfrail females aged 60+ y from the Nurses' Health Study (cohort study) were followed up for ≥26 y. Diet was assessed every 4 y by food frequency questionnaires. UPF and UMF intakes were calculated using the Nova classification. Diet quality was estimated using the Alternate Healthy Eating Index (AHEI) 2010. The association of UMF and UPF with risk of frailty was examined using multivariable adjusted Cox proportional hazard model.

RESULTS

During the follow-up period, we recorded 15,187 incident cases of frailty. The hazard ratio (HR) of frailty for the highest compared with the lowest quintile of UMFs (servings per day) was 0.86 (95% CI: 0.83, 0.95; P-trend < 0.001). However, this was no longer statistically significant after adjustment for AHEI-2010. UPFs (servings per day) was directly associated with risk of frailty, even after adjustment for AHEI-2010 (1.31; 95% CI: 1.23, 1.39; P-trend < 0.001). Among those at the highest category of the AHEI-2010, UPFs remained directly associated with frailty (HR comparing top with bottom quintile: 1.40; 95% CI:1.24, 1.57; P-trend < 0.001). For UPF components, we found a higher frailty risk with each serving per day of artificial and sugar-sweetened beverages; fat, spreads, and condiments; yogurt and dairy-based desserts; and other UPFs. However, processed whole grains were not associated with frailty.

CONCLUSIONS

Higher intake of UPF is associated with a higher risk of frailty in older females. This is not explained by a lower diet quality contributed by UPFs.

Probiotic-Reduced Inflammaging in Older Adults: A Randomized, Double-Blind, Placebo-Controlled Trial

The disparity between increased lifespan and healthy aging, marked by prevalent "inflammaging", highlights the global challenge in care of older persons. This study explored the anti-inflammatory effects of Lactiplantibacillus plantarum HEAL9 (LpHEAL9), alone or combined with berries, on older volunteers with chronic low-grade inflammation (LGI). It was a randomized, double-blind, placebo-controlled trial, with a total of 66 volunteers (> 70 years old), randomly assigned, and equally distributed, to placebo, LpHEAL9 or LpHEAL9 + Berries group. After a 2-week run-in period, participants underwent a 4-week dietary intervention. Intake of LpHEAL9 showed a trend towards reduction in serum CRP but without reaching statistical significance. However, LpHEAL9 significantly decreased fecal calprotectin levels compared to placebo. LpHEAL9+Berries did not show any effect on inflammation. Both probiotic groups showed a trend in improving cognitive function albeit not reaching statistical significance. Our findings suggest that the probiotic strain L. plantarum HEAL9 has a modest impact on LGI in a healthy older population (ClinicalTrials.gov ID: NCT02342496).

Geroprotective interventions converge on gene expression programs of reduced inflammation and restored fatty acid metabolism

Understanding the mechanisms of geroprotective interventions is central to aging research. We compare four prominent interventions: senolysis, caloric restriction, in vivo partial reprogramming, and heterochronic parabiosis. Using published mice transcriptomic data, we juxtapose these interventions against normal aging. We find a gene expression program common to all four interventions, in which inflammation is reduced and several metabolic processes, especially fatty acid metabolism, are increased. Normal aging exhibits the inverse of this signature across multiple organs and tissues. A similar inverse signature arises in three chronic inflammation disease models in a non-aging context, suggesting that the shift in metabolism occurs downstream of inflammation. Chronic inflammation is also shown to accelerate transcriptomic age. We conclude that a core mechanism of geroprotective interventions acts through the reduction of inflammation with downstream effects that restore fatty acid metabolism. This supports the notion of directly targeting genes associated with these pathways to mitigate age-related deterioration.

Senolytic CAR T cells reverse aging-associated defects in intestinal regeneration and fitness

Intestinal stem cells (ISCs) drive the rapid regeneration of the gut epithelium to maintain organismal homeostasis. Aging, however, significantly reduces intestinal regenerative capacity. While cellular senescence is a key feature of the aging process, little is known about the in vivo effects of senescent cells on intestinal fitness. Here, we identify the accumulation of senescent cells in the aging gut and, by harnessing senolytic CAR T cells to eliminate them, we uncover their detrimental impact on epithelial integrity and overall intestinal homeostasis in natural aging, injury and colitis. Ablation of intestinal senescent cells with senolytic CAR T cells in vivo or in vitro is sufficient to promote the regenerative potential of aged ISCs. This intervention improves epithelial integrity and mucosal immune function. Overall, these results highlight the ability of senolytic CAR T cells to rejuvenate the intestinal niche and demonstrate the potential of targeted cell therapies to promote tissue regeneration in aging organisms.

Evidence that the loss of colonic anti-microbial peptides may promote dysbiotic Gram-negative inflammaging-associated bacteria in aging mice

Introduction: Aging studies in humans and mice have played a key role in understanding the intestinal microbiome and an increased abundance of "inflammaging" Gram-negative (Gn) bacteria. The mechanisms underlying this inflammatory profile in the aging microbiome are unknown. We tested the hypothesis that an aging-related decrease in colonic crypt epithelial cell anti-microbial peptide (AMP) gene expression could promote colonic microbiome inflammatory Gn dysbiosis and inflammaging. Methods: As a model of aging, C57BL/6J mice fecal (colonic) microbiota (16S) and isolated colonic crypt epithelial cell gene expression (RNA-seq) were assessed at 2 months (mth) (human: 18 years old; yo), 15 mth (human: 50 yo), and 25 mth (human: 84 yo). Informatics examined aging-related microbial compositions, differential colonic crypt epithelial cell gene expressions, and correlations between colonic bacteria and colonic crypt epithelial cell gene expressions. Results: Fecal microbiota exhibited significantly increased relative abundances of pro-inflammatory Gn bacteria with aging. Colonic crypt epithelial cell gene expression analysis showed significant age-related downregulation of key AMP genes that repress the growth of Gn bacteria. The aging-related decrease in AMP gene expressions is significantly correlated with an increased abundance in Gn bacteria (dysbiosis), loss of colonic barrier gene expression, and senescence- and inflammation-related gene expression. Conclusion: This study supports the proposed model that aging-related loss of colonic crypt epithelial cell AMP gene expression promotes increased relative abundances of Gn inflammaging-associated bacteria and gene expression markers of colonic inflammaging. These data may support new targets for aging-related therapies based on intestinal genes and microbiomes.

Exploring the emerging bidirectional association between inflamm-aging and cellular senescence in organismal aging and disease

There is strong evidence that most individuals in the elderly population are characterized by inflamm-aging which refers to a subtle increase in the systemic pro-inflammatory environment and impaired innate immune activation. Although a variety of distinct factors are associated with the progression of inflamm-aging, emerging research is demonstrating a dynamic relationship between the processes of cellular senescence and inflamm-aging. Cellular senescence is a recognized factor governing organismal aging, and through a characteristic secretome, accumulating senescent cells can induce and augment a pro-inflammatory tissue environment that provides a rationale for immune system-independent activation of inflamm-aging and associated diseases. There is also accumulating evidence that inflamm-aging or its components can directly accelerate the development of senescent cells and ultimately senescent cell burden in tissues in a likely vicious inflammatory loop. The present review is intended to describe the emerging senescence-based molecular etiology of inflamm-aging as well as the dynamic reciprocal interactions between inflamm-aging and cellular senescence. Therapeutic interventions concurrently targeting cellular senescence and inflamm-aging are discussed and limitations as well as research opportunities have been deliberated. An effort has been made to provide a rationale for integrating inflamm-aging with cellular senescence both as an underlying cause and therapeutic target for further studies.

Risk of Social Isolation as a Contributing Factor to Diet Quality in Community-Dwelling Older Persons Living in the Australian Capital Territory-A Pilot Study

OBJECTIVES

Social isolation is recognised as a risk factor in the inflammatory process. This study explored the association between social isolation and the Dietary Inflammatory Index (DII) in community-dwelling older persons.

METHODS

This cross-sectional pilot study recruited 107 community-dwelling people aged over 55 years living in the Australian Capital Territory. Participants completed an extensive food frequency questionnaire and provided anthropometric and sociodemographic data. Social isolation was evaluated using the Lubben Social Network Scale (LSNS). Diet quality was assessed using DII.

RESULTS

Average age was 70.1 (±8.61) years and 62.8% were female. The average DII score was -1.10 (±1.21), indicating an anti-inflammatory diet. Higher LSNS was associated with lower DII (b (95% CI) = -0.041 (-0.066, -0.17); p < 0.01) and was positively influenced by the number of people in household (b (95% CI) = 5.731 (2.336, 9.127); p = 0.001).

CONCLUSION

Increased risk of social isolation was associated with an increased tendency towards a more inflammatory diet. Reducing social isolation may decrease the inflammatory component of dietary intake for older persons living independently in the community.

Integrated analysis revealing novel associations between dietary patterns and the immune system in older adults

With the expanding ageing population, there is a growing interest in the maintenance of immune health to support healthy ageing. Enthusiasm exists for unravelling the impact of diet on the immune system and its therapeutic potential. However, a key challenge is the lack of studies investigating the effect of dietary patterns and nutrients on immune responses. Thus, we have used an integrative analysis approach to improve our understanding of diet-immune system interactions in older adults. To do so, dietary data were collected in parallel with performing immunophenotyping and functional assays from healthy older (n = 40) participants. Food Frequency Questionnaire (FFQ) was utilised to derive food group intake and multi-colour flow cytometry was performed for immune phenotypic and functional analysis. Spearman correlation revealed the strength of association between all combinations of dietary components, micronutrients, and hallmarks of immunesenescence. In this study, we propose for the first time that higher adherence to the Mediterranean diet is associated with a positive immune-ageing trajectory (Lower IMM-AGE score) in older adults due to the immune protective effects of high dietary fibre and PUFA intake in combating accumulation or pro-inflammatory senescent T cells. Furthermore, a diet rich in Vit A, Vit B6 and Vit B12 is associated with fewer features of immunesenescence [such as accumulation of terminally differentiated memory CD8 T cells] in older adults. Based on our findings we propose a future nutrition-based intervention study evaluating the efficacy of adherence to the MED diet alongside a multi-nutrient supplementation on immune ageing in older adults to set reliable dietary recommendations with policymakers that can be given to geriatricians and older adults. Insight box: There is a growing interest in the maintenance of immune health to boost healthy ageing. However, a key challenge is the lack of studies investigating the effect of dietary patterns and nutrients on immune responses. Thus, to do so we collected dietary data in parallel with performing immunophenotyping and functional assays on healthy older (n = 40) participants, followed by an integrative analysis approach to improve our understanding of diet-immune system interactions in older adults. We strongly believe that these new findings are appropriate for IB and will be of considerable interest to its broad audience.

Aging Hallmarks and Progression and Age-Related Diseases: A Landscape View of Research Advancement

Aging is a dynamic, time-dependent process that is characterized by a gradual accumulation of cell damage. Continual functional decline in the intrinsic ability of living organisms to accurately regulate homeostasis leads to increased susceptibility and vulnerability to diseases. Many efforts have been put forth to understand and prevent the effects of aging. Thus, the major cellular and molecular hallmarks of aging have been identified, and their relationships to age-related diseases and malfunctions have been explored. Here, we use data from the CAS Content Collection to analyze the publication landscape of recent aging-related research. We review the advances in knowledge and delineate trends in research advancements on aging factors and attributes across time and geography. We also review the current concepts related to the major aging hallmarks on the molecular, cellular, and organismic level, age-associated diseases, with attention to brain aging and brain health, as well as the major biochemical processes associated with aging. Major age-related diseases have been outlined, and their correlations with the major aging features and attributes are explored. We hope this review will be helpful for apprehending the current knowledge in the field of aging mechanisms and progression, in an effort to further solve the remaining challenges and fulfill its potential.

Integrated multicomponent interventions to support healthy aging of the whole person

Healthy aging is an integrated "whole person" process that involves an individual's biology, behavior, and social/physical environment. With the recent development of antiaging drugs, careful consideration of the respective roles of pharmacologic and nonpharmacologic approaches to both health and aging is in order. Recent advances in understanding the cellular and molecular mechanisms of aging are providing new measures that can be used as clinical outcomes in studying the impact of antiaging interventions in humans. This paper outlines the strategic interest of the National Center for Complementary and Integrative Health (NCCIH) in supporting the development, testing, and implementation of effective, scalable, and integrated multicomponent interventions to support healthy aging of the whole person.

Osteoarthritis in the Elderly Population: Preclinical Evidence of Nutrigenomic Activities of Flavonoids

Osteoarthritis (OA) is a degenerative joint disease that is age-related and progressive. It causes the destruction of articular cartilage and underlying bone, often aggravated by inflammatory processes and oxidative stresses. This pathology impairs the quality of life of the elderly, causing pain, reduced mobility, and functional disabilities, especially in obese patients. Phytochemicals with anti-inflammatory and antioxidant activities may be used for long-term treatment of OA, either in combination with current anti-inflammatories and painkillers, or as an alternative to other products such as glucosamine and chondroitin, which improve cartilage structure and elasticity. The current systematic review provides a comprehensive understanding of the use of flavonoids. It highlights chondrocyte, cartilage, and subchondral bone activities, with a particular focus on their nutrigenomic effects. The molecular mechanisms of these molecules demonstrate how they can be used for the prevention and treatment of OA in the elderly population. However, clinical trials are still needed for effective use in clinical practice.

Pentadecanoic Acid (C15:0), an Essential Fatty Acid, Shares Clinically Relevant Cell-Based Activities with Leading Longevity-Enhancing Compounds

Pentadecanoic acid (C15:0) is an essential odd-chain saturated fatty acid with broad activities relevant to protecting cardiometabolic, immune, and liver health. C15:0 activates AMPK and inhibits mTOR, both of which are core components of the human longevity pathway. To assess the potential for C15:0 to enhance processes associated with longevity and healthspan, we used human cell-based molecular phenotyping assays to compare C15:0 with three longevity-enhancing candidates: acarbose, metformin, and rapamycin. C15:0 (n = 36 activities in 10 of 12 cell systems) and rapamycin (n = 32 activities in 12 of 12 systems) had the most clinically relevant, dose-dependent activities. At their optimal doses, C15:0 (17 µM) and rapamycin (9 µM) shared 24 activities across 10 cell systems, including anti-inflammatory (e.g., lowered MCP-1, TNFα, IL-10, IL-17A/F), antifibrotic, and anticancer activities, which are further supported by previously published in vitro and in vivo studies. Paired with prior demonstrated abilities for C15:0 to target longevity pathways, hallmarks of aging, aging rate biomarkers, and core components of type 2 diabetes, heart disease, cancer, and nonalcoholic fatty liver disease, our results support C15:0 as an essential nutrient with activities equivalent to, or surpassing, leading longevity-enhancing candidate compounds.

Inverse J-Shaped Relationship of Dietary Carbohydrate Intake with Serum Klotho in NHANES 2007-2016

BACKGROUND

The relationship between dietary carbohydrate intake and serum Klotho levels, an aging biomarker, remains uncertain.

OBJECTIVE

This study aimed to investigate the association between dietary carbohydrate intake and serum Klotho levels among American adults aged 40-79.

METHODS

We analyzed data from 10,669 adults aged 40-79 years who participated in the National Health and Nutrition Examination Survey (NHANES) from 2007 to 2016. Trained interviewers assessed dietary carbohydrate intake using a 24 h dietary recall. Serum Klotho concentrations were measured using commercially available ELISA kits provided by IBL International, Japan, which served as the study outcome. Generalized linear models were used to assess the relationship between the carbohydrate energy percentage and serum Klotho concentration, and restricted cubic spline (RCS) analysis was employed to explore any nonlinear associations.

RESULTS

After adjusting for multiple variables, we observed a nonlinear inverse J-shaped relationship (p for non-linearity < 0.001) between the carbohydrate energy percentage and serum Klotho levels. Specifically, the highest serum Klotho levels were associated with a total carbohydrate energy percentage ranging from 48.92% to 56.20% (third quartile). When the carbohydrate energy percentage was evaluated in quartiles, serum Klotho levels decreased by 5.37% (95% CI: -7.43%, -3.26%), 2.70% (95% CI: -4.51%, -0.86%), and 2.76% (95% CI: -4.86%, -0.62%) in the first quartile (<41.46%), second quartile (41.46% to 48.92%), and fourth quartile (≥56.20%), respectively, compared to the third quartile. This relationship was more pronounced in male, non-obese and non-diabetic participants under 60 years of age.

CONCLUSION

A non-linear inverse J-shaped relationship exists among the general U.S. middle-aged and older population between the carbohydrate energy percentage and serum Klotho levels, with the highest levels observed at 48.92% to 56.20% carbohydrate intake.

Back to the Basics: Usefulness of Naturally Aged Mouse Models and Immunohistochemical and Quantitative Morphologic Methods in Studying Mechanisms of Lung Aging and Associated Diseases

Aging-related molecular and cellular alterations in the lung contribute to an increased susceptibility of the elderly to devastating diseases. Although the study of the aging process in the lung may benefit from the use of genetically modified mouse models and omics techniques, these approaches are still not available to most researchers and produce complex results. In this article, we review works that used naturally aged mouse models, together with immunohistochemistry (IHC) and quantitative morphologic (QM) methods in the study of the mechanisms of the aging process in the lung and its most commonly associated disorders: cancer, chronic obstructive pulmonary disease (COPD), and infectious diseases. The advantage of using naturally aged mice is that they present characteristics similar to those observed in human aging. The advantage of using IHC and QM methods lies in their simplicity, economic accessibility, and easy interpretation, in addition to the fact that they provide extremely important information. The study of the aging process in the lung and its associated diseases could allow the design of appropriate therapeutic strategies, which is extremely important considering that life expectancy and the number of elderly people continue to increase considerably worldwide.

Up-regulation of Myocardial Klotho Expression to Promote Cardiac Functional Recovery in Old Mice following Endotoxemia

Objective

Endotoxemic cardiac dysfunction contributes to greater morbidity and mortality in elderly patients with sepsis. This study tested the hypothesis that Klotho insufficiency in aging heart exaggerates and prolongs myocardial inflammation to hinder cardiac function recovery following endotoxemia.

Methods

Endotoxin (0.5 mg/kg, iv) was administered to young adult (3-4 months) and old (18-22 months) mice with or without subsequent treatment with recombinant interleukin-37 (IL-37, 50 μg/kg, iv) or recombinant Klotho (10 μg/kg, iv). Cardiac function was analyzed using a microcatheter 24, 48 and 96 h later. Myocardial levels of Klotho, ICAM-1, VCAM-1 and IL-6 were determined by immunoblotting and ELISA.

Results

In comparison to young adult mice, old mice had worse cardiac dysfunction accompanied by greater myocardial levels of ICAM-1, VCAM-1 and IL-6 at each time point following endotoxemia and failed to fully recover cardiac function by 96 h. The exacerbated myocardial inflammation and cardiac dysfunction were associated with endotoxemia-caused further reduction of lower myocardial Klotho level in old mice. Recombinant IL-37 promoted inflammation resolution and cardiac functional recovery in old mice. Interestingly, recombinant IL-37 markedly up-regulated myocardial Klotho levels in old mice with or without endotoxemia. Similarly, recombinant Klotho suppressed myocardial inflammatory response and promoted inflammation resolution in old endotoxemic mice, leading to complete recovery of cardiac function by 96 h.

Conclusion

Myocardial Klotho insufficiency in old endotoxemic mice exacerbates myocardial inflammatory response, impairs inflammation resolution and thereby hinders cardiac functional recovery. IL-37 is capable of up-regulating myocardial Klotho expression to improve cardiac functional recovery in old endotoxemic mice.

Anti-Inflammatory Klotho Protein Serum Concentration Correlates with Interferon Gamma Expression Related to the Cellular Activity of Both NKT-like and T Cells in the Process of Human Aging

Klotho is a beta-glucuronidase that reveals both anti-inflammatory and anti-oxidative properties that have been associated with mechanisms of aging. The study aimed to analyze the relationships between the serum concentration of soluble α-Klotho and cellular activity of two populations of lymphocytes; T and NKT-like cells corresponding to the level of cytokine secretion; i.e., IFN-γ, TNF-α, and IL-6. The studied population comprised three age groups: young individuals ('young'), seniors aged under 85 ('old'), and seniors aged over 85 ('oldest'). Both NKT-like and T cells were either non-cultured or cultured for 48 h and stimulated appropriately with IL-2, LPS or PMA with ionomycin to compare with unstimulated control cells. In all studied age groups non-cultured or cultured NKT-like cells revealed higher expressions of TNF-α, IL-6, and IFN-γ than T cells. α-Klotho concentration in serum decreased significantly in the process of aging. Intriguingly, only IFN-γ expression revealed a positive correlation with α-Klotho protein serum concentration in both non-cultured and cultured T and NKT-like cells. Since IFN-γ is engaged in the maintenance of immune homeostasis, the observed relationships may indicate the involvement of α-Klotho and cellular IFN-γ expression in the network of adaptive mechanisms developed during the process of human aging.

Uremic Toxin Indoxyl Sulfate Promotes Macrophage-Associated Low-Grade Inflammation and Epithelial Cell Senescence

In this study, we investigated the impact of the uremic toxin indoxyl sulfate on macrophages and tubular epithelial cells and its role in modulating the response to lipopolysaccharide (LPS). Indoxyl sulfate accumulates in the blood of patients with chronic kidney disease (CKD) and is a predictor of overall and cardiovascular morbidity/mortality. To simulate the uremic condition, primary macrophages and tubular epithelial cells were incubated with indoxyl sulfate at low concentrations as well as concentrations found in uremic patients, both alone and upon LPS challenge. The results showed that indoxyl sulfate alone induced the release of reactive oxygen species and low-grade inflammation in macrophages. Moreover, combined with LPS (proinflammatory conditions), indoxyl sulfate significantly increased TNF-α, CCL2, and IL-10 release but did not significantly affect the polarization of macrophages. Pre-treatment with indoxyl sulfate following LPS challenge induced the expression of aryl hydrocarbon receptor (Ahr) and NADPH oxidase 4 (Nox4) which generate reactive oxygen species (ROS). Further, experiments with tubular epithelial cells revealed that indoxyl sulfate might induce senescence in parenchymal cells and therefore participate in the progression of inflammaging. In conclusion, this study provides evidence that indoxyl sulfate provokes low-grade inflammation, modulates macrophage function, and enhances the inflammatory response associated with LPS. Finally, indoxyl sulfate signaling contributes to the senescence of tubular epithelial cells during injury.

Effects of Caloric Restriction on Spatial Object Recognition Memory, Hippocampal Neuron Loss and Neuroinflammation in Aged Rats

Age-related neurobiological changes significantly affect hippocampal structure and function, such that the main cognitive impairments associated with aging are related to the integrity of this brain structure, including the deterioration in spatial object recognition (SOR) memory. Previous studies have shown that intrinsic factors such as neuroinflammation, as well as lifestyle factors such as diet, can affect aging-associated brain functions and cognitive performance. In this regard, caloric restriction (CR) produces beneficial effects on health and life expectancy, although its ability to slow down age-dependent effects on cognitive decline and hippocampus (HPC) functioning remains unclear. Therefore, we set out to evaluate the effects of CR on SOR memory in aged male Wistar rats, as well as those on hippocampal neuron loss, neurogenesis and inflammation. The data show that CR in aged rats attenuates the decline in SOR memory, age-associated hippocampal neuron loss, and age-dependent microglial activation. Furthermore, we found a significant reduction in neurogenesis in the dentate gyrus of the old animals relative to adult rats. These findings support the positive effect of CR on SOR memory, suggesting that it dampens hippocampal neuronal loss and reduces proinflammatory activity.

Genetic Networks of Alzheimer's Disease, Aging, and Longevity in Humans

Human genomic analysis and genome-wide association studies (GWAS) have identified genes that are risk factors for early and late-onset Alzheimer's disease (AD genes). Although the genetics of aging and longevity have been extensively studied, previous studies have focused on a specific set of genes that have been shown to contribute to or are a risk factor for AD. Thus, the connections among the genes involved in AD, aging, and longevity are not well understood. Here, we identified the genetic interaction networks (referred to as pathways) of aging and longevity within the context of AD by using a gene set enrichment analysis by Reactome that cross-references more than 100 bioinformatic databases to allow interpretation of the biological functions of gene sets through a wide variety of gene networks. We validated the pathways with a threshold of p-value < 1.00 × 10^-5 using the databases to extract lists of 356 AD genes, 307 aging-related (AR) genes, and 357 longevity genes. There was a broad range of biological pathways involved in AR and longevity genes shared with AD genes. AR genes identified 261 pathways within the threshold of p < 1.00 × 10^-5, of which 26 pathways (10% of AR gene pathways) were further identified by overlapping genes among AD and AR genes. The overlapped pathways included gene expression (p = 4.05 × 10^-11) including ApoE, SOD2, TP53, and TGFB1 (p = 2.84 × 10^-10); protein metabolism and SUMOylation, including E3 ligases and target proteins (p = 1.08 × 10^-7); ERBB4 signal transduction (p = 2.69 × 10^-6); the immune system, including IL-3 and IL-13 (p = 3.83 × 10^-6); programmed cell death (p = 4.36 × 10^-6); and platelet degranulation (p = 8.16 × 10^-6), among others. Longevity genes identified 49 pathways within the threshold, of which 12 pathways (24% of longevity gene pathways) were further identified by overlapping genes among AD and longevity genes. They include the immune system, including IL-3 and IL-13 (p = 7.64 × 10^-8), plasma lipoprotein assembly, remodeling and clearance (p < 4.02 × 10^-6), and the metabolism of fat-soluble vitamins (p = 1.96 × 10^-5). Thus, this study provides shared genetic hallmarks of aging, longevity, and AD backed up by statistical significance. We discuss the significant genes involved in these pathways, including TP53, FOXO, SUMOylation, IL4, IL6, APOE, and CEPT, and suggest that mapping the gene network pathways provide a useful basis for further medical research on AD and healthy aging.