Effects of Aging on Fracture Healing

PURPOSE OF REVIEW

This review summarizes research on the physiological changes that occur with aging and the resulting effects on fracture healing.

RECENT FINDINGS

Aging affects the inflammatory response during fracture healing through senescence of the immune response and increased systemic pro-inflammatory status. Important cells of the inflammatory response, macrophages, T cells, mesenchymal stem cells, have demonstrated intrinsic age-related changes that could impact fracture healing. Additionally, vascularization and angiogenesis are impaired in fracture healing of the elderly. Finally, osteochondral cells and their progenitors demonstrate decreased activity and quantity within the callus. Age-related changes affect many of the biologic processes involved in fracture healing. However, the contributions of such changes do not fully explain the poorer healing outcomes and increased morbidity reported in elderly patients. Future research should address this gap in understanding in order to provide improved and more directed treatment options for the elderly population.

MicroRNAs linking inflamm-aging, cellular senescence and cancer

Epidemiological and experimental data demonstrate a strong correlation between age-related chronic inflammation (inflamm-aging) and cancer development. However, a comprehensive approach is needed to clarify the underlying molecular mechanisms. Chronic inflammation has mainly been attributed to continuous immune cells activation, but the cellular senescence process, which may involve acquisition of a senescence-associated secretory phenotype (SASP), can be another important contributor, especially in the elderly. MicroRNAs (miRs), a class of molecules involved in gene expression regulation, are emerging as modulators of some pathways, including NF-κB, mTOR, sirtuins, TGF-β and Wnt, that may be related to inflammation, cellular senescence and age-related diseases, cancer included. Interestingly, cancer development is largely avoided or delayed in centenarians, where changes in some miRs are found in plasma and leukocytes. We identified miRs that can be considered as senescence-associated (SA-miRs), inflammation-associated (inflamma-miRs) and cancer-associated (onco-miRs). Here we review recent findings concerning three of them, miR-21, -126 and -146a, which target mRNAs belonging to the NF-κB pathway; we discuss their ability to link cellular senescence, inflamm-aging and cancer and their changes in centenarians, and provide an update on the possibility of using miRs to block accumulation of senescent cells to prevent formation of a microenvironment favoring cancer development and progression.

Sarcopenia--The search for emerging biomarkers

Sarcopenia, an age-related decline in skeletal muscle mass and function, dramatically affects the life quality of elder people. In view of increasing life expectancy, sarcopenia renders a heavy burden on the health care system. However, although there is a consensus that sarcopenia is a multifactorial syndrome, its etiology, underlying mechanisms, and even definition remain poorly delineated, thus, preventing development of a precise treatment strategy. The main aim of our review is to critically analyze potential sarcopenia biomarkers in light of the molecular mechanisms of their involvement in sarcopenia pathogenesis. Normal muscle mass and function maintenance are proposed to be dependent on the dynamic balance between the positive regulators of muscle growth such as bone morphogenetic proteins (BMPs), brain-derived neurotrophic factor (BDNF), follistatin (FST) and irisin, and negative regulators including TGFβ, myostatin, activins A and B, and growth and differentiation factor-15 (GDF-15). We hypothesize that the shift in this balance to muscle growth inhibitors, along with increased expression of the C- terminal agrin fragment (CAF) associated with age-dependent neuromuscular junction (NMJ) dysfunction, as well as skeletal muscle-specific troponin T (sTnT), a key component of contractile machinery, is a main mechanism underlying sarcopenia pathogenesis. Thus, this review proposes and emphasizes that these molecules are the emerging sarcopenia biomarkers.

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

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

Age-related differences in the neutrophil response to pulmonary pseudomonas infection

BACKGROUND

Pseudomonas aeruginosa pneumonia is more common and more lethal in the elderly. The immunologic underpinnings of this increased incidence and mortality have not been evaluated, however are assumed to be a complication of age-associated immune dysfunction.

METHODS

Young (10-12week old) and aged (18-20month old) BALB/c mice were subjected to intratracheal infection of P. aeruginosa. Animals were sacrificed 24h after inoculation. The lungs were collected for analysis of lung pathology, chemokine levels, neutrophil counts, and myeloperoxidase activity.

RESULTS

Pulmonary levels of the neutrophil chemokine KC are significantly higher in aged mice relative to young following P. aeruginosa infection. Despite this, neutrophil counts are higher in young mice compared to aged mice after infection. Furthermore, the neutrophils are predominantly found in the air space of young infected mice. This correlated with increased myeloperoxidase activity from bronchoalveolar lavage specimens of young mice relative to aged mice after infection.

CONCLUSIONS

Neutrophil migration into the lungs is impaired in aged mice 24h after intratracheal infection despite elevated chemokine levels, suggesting that immunosenescence is impairing neutrophil migration.

Traumatic Stress and Accelerated Cellular Aging: From Epigenetics to Cardiometabolic Disease

PURPOSE OF REVIEW

The aim of this paper is to review the recent literature on traumatic stress-related accelerated aging, including a focus on cellular mechanisms and biomarkers of cellular aging and on the clinical manifestations of accelerated biological aging.

RECENT FINDINGS

Multiple lines of research converge to suggest that PTSD is associated with accelerated aging in the epigenome, and the immune and inflammation systems, and this may be reflected in premature onset of cardiometabolic and cardiovascular disease. The current state of research paves the way for future work focused on identifying the peripheral and central biological mechanisms linking traumatic stress to accelerated biological aging and medical morbidity, with an emphasis on processes involved in inflammation, immune functioning, oxidative stress, autonomic arousal, and stress response. Ultimately, such work could help reduce the pace of biological aging and improve health and wellness.

Trafficking phenotype and production of granzyme B by double negative B cells (IgG(+)IgD(-)CD27(-)) in the elderly

The impairment of humoral immune response in elderly humans has been extensively demonstrated. We have reported the increase of memory B cells (IgG(+)IgD(-)CD27(-), double negative, DN) population in the elderly, in which there is also a typical inflammatory micro-environment. In order to evaluate whether this pro-inflammatory status could influence the trafficking phenotype of naïve/memory B cells, we have assessed the expression of CCR7, CCR6, CXCR3, CXCR4, CXCR5 and CD62L on naïve/memory B cell subpopulations in young and elderly subjects. Moreover, the combination of pro-inflammatory interleukin-21 (IL-21) and B cell receptor (BCR) stimulation enables B cells to produce and secrete granzyme B (GrB), which plays a critical role in early anti-viral immune responses, in the regulation of autoimmune mechanisms and in cancer immunosurveillance. Our data demonstrate that in the elderly, naïve/memory B cell populations present a different expression of the studied receptors that could be discussed in terms of "inflamm-aging". In particular IgG(+)IgD(-)CD27(-) DN B cells show a tissue trafficking phenotype and they can be stimulated to produce GrB.

Effect of a polyphenol-rich dietary pattern on intestinal permeability and gut and blood microbiomics in older subjects: study protocol of the MaPLE randomised controlled trial

Background

During aging, alterations of the intestinal microbial ecosystem can occur contributing to immunosenescence, inflamm-aging and impairment of intestinal barrier function (increased intestinal permeability; IP). In the context of a diet-microbiota-IP axis in older subjects, food bioactives such as polyphenols may play a beneficial modulatory role.

Methods

MaPLE is a project centered on a randomized, controlled cross-over dietary intervention trial [polyphenol-rich diet (PR-diet) versus control diet (C-diet)] targeted to older people (≥ 60 y) living in a well-controlled setting (i.e. nursing home). The 8-week interventions are separated by an 8-week wash-out period. Three small portions per day of selected polyphenol-rich foods are consumed during intervention in substitution of other comparable products within the C-diet. Biological samples are collected before and after each treatment period to evaluate markers related to IP, inflammation, vascular function, oxidative stress, gut and blood microbiomics, metabolomics. A sample size of 50 subjects was defined based on IP as primary outcome.

Discussion

Evidence that increasing the consumption of polyphenol-rich food products can positively affect intestinal microbial ecosystem resulting in reduced IP and decreased translocation of inflammogenic bacterial factors into the bloodstream will be provided. The integration of data from gut and blood microbiomics, metabolomics and other IP-related markers will improve the understanding of the beneficial effect of the intervention in the context of polyphenols−microbiota−IP interactions. Finally, findings obtained will provide a proof of concept of the reliability of the dietary intervention, also contributing to future implementations of dietary guidelines directed to IP management in the older and other at risk subjects.

Trial registration

The trial is registered at (ISRCTN10214981); April 28, 2017.

A review of the equine age-related changes in the immune system: comparisons between human and equine aging, with focus on lung-specific immune-aging

The equine aging process involves many changes to the immune system that may be related to genetics, the level of nutrition, the environment and/or an underlying subclinical disease. Geriatric horses defined as horses above the age of 20, exhibit a decline in body condition, muscle tone and general well-being. It is not known whether these changes contribute to decreased immune function or are the result of declining immune function. Geriatric years are characterized by increased susceptibility to infections and a reduced antibody response to vaccination as a result of changes in the immune system. Humans and horses share many of these age-related changes, with only a few differences. Thus, inflamm-aging and immunosenescence are well-described phenomena in both human and equine research, particularly in relation to the peripheral blood and especially the T-cell compartment. However, the lung is faced with unique challenges because of its constant interaction with the external environment and thus may not share similarities to peripheral blood when considering age-related changes in immune function. Indeed, recent studies have shown discrepancies in cytokine mRNA and protein expression between the peripheral blood and bronchoalveolar lavage immune cells. These results provide important evidence that age-related immune changes or 'dys-functions' are organ-specific.

First evidence for STING SNP R293Q being protective regarding obesity-associated cardiovascular disease in age-advanced subjects - a cohort study

Obesity is a risk factor for several aging-related diseases such as type 2 diabetes, cardiovascular disease, and cancer. Especially, cardiovascular disease is triggered by obesity by inducing vascular senescence and chronic low-grade systemic inflammation, also known as inflamm-aging. Released molecules from damaged cells and their recognition by the innate immune system is one of the mechanisms driving inflamm-aging. Obesity results in mitochondrial damage, leading to endothelial inflammation triggered by cytosolic mtDNA via the cGAS/STING pathway. Recently, we have shown STING SNP R293Q to be associated with a decreased risk for aging-related diseases in current smokers. Since current smoking triggers DNA damage that, similar to obesity, may result in the release of DNA into the cytoplasm, we hypothesized that the cGAS/STING pathway can modify the phenotype of aging also in obese subjects. Therefore, the objective of our study was to investigate whether STING R293Q is associated with aging-related diseases in obese individuals. We indeed show that STING 293Q is associated with protection from combined aging-related diseases (P = 0.014) and, in particular, cardiovascular disease in these subjects (P = 0.010). Therefore, we provide the first evidence that stratification for obesity may reveal new genetic loci determining the risk for aging-related diseases.

The Expression Changes of Inflammasomes in the Aging Rat Kidneys

The mechanisms of kidney aging are not yet clear. Studies have shown that immunological inflammation is related to kidney aging. Inflammasomes are important components of innate immune system in the body. However, the function of inflammasomes and their underlying mechanisms in renal aging remain unclear. In this study, for the first time, we systematically investigated the role of the inflammasomes and the inflammatory responses activated by inflammasomes during kidney aging. We found that during kidney aging, the expression levels of the molecules associated with the activation of inflammasomes, including toll-like receptor-4 and interleukin-1 receptor (IL-1R), were significantly increased; their downstream signaling pathway molecule interleukin-1 receptor-associated kinase-4 (IRAK4) was markedly activated (Phospho-IRAK4 was obviously increased); the nuclear factor-κB (NF-κB) signaling pathway was activated (the activated NF-κB pathway molecules Phospho-IKKβ, Phospho-IκBα, and Phospho-NF-κBp65 were significantly elevated); the levels of the inflammasome components NOD-like receptor P3 (NLRP3), NLRC4, and pro-caspase-1 were prominently upregulated; and the proinflammatory cytokines IL-1β and IL-18 were notably increased in the kidneys of 24-month-old (elderly group) rats. These results showed that inflammasomes are markedly activated during the renal aging process and might induce inflamm-aging by promoting the maturation and secretion of the proinflammatory cytokines IL-1β and IL-18.

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

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

Relationships of inflamm-aging with circulating nutrient levels, body composition, age, and pituitary pars intermedia dysfunction in a senior horse population

Similarly to aged humans, senior horses (≥20 years) exhibit chronic low-grade inflammation systemically, known as inflamm-aging. Inflamm-aging in the senior horse has been characterized by increased circulating inflammatory cytokines as well as increased inflammatory cytokine production by lymphocytes and monocytes in response to a mitogen. Little is currently known regarding underlying causes of inflamm-aging. However, senior horses are also known to present with muscle wasting and often the endocrinopathy pituitary pars intermedia dysfunction (PPID). Despite the concurrence of these phenomena, the relationships inflamm-aging may have with measures of body composition and pituitary function in the horse remain unknown. Furthermore, nutrition has been a focus of research in an attempt to promote health span as well as life span in senior horses, with some nutrients, such as omega-3 fatty acids, having known anti-inflammatory effects. Thus, an exploratory study of a population of n = 42 similarly-managed senior horses was conducted to determine relationships between inflamm-aging and measures of circulating nutrients, body composition, age, and PPID. Serum was collected to determine vitamin, mineral, and fatty acid content. Peripheral blood mononuclear cells were also isolated to determine inflammatory cytokine production of interferon-γ (IFN-γ) and tumor necrosis factor-α (TNF-α) following stimulation with a mitogen, as well as to determine gene expression of interleukin(IL)-1β, IL-6, IL-10, IFN-γ, and TNF-α. Serum IL-6 and C-reactive protein were determined by enzyme-linked immunosorbent assay. Whole blood was collected for hematological and biochemical analysis. Body composition was evaluated via ultrasound and muscle scoring for all 42 horses as well as by deuterium oxide dilution for a subset of n = 10 horses. Pituitary function was evaluated by measuring basal adrenocorticotropin hormone concentrations as well as by thyrotropin releasing hormone stimulation testing (to determine PPID status). Results showed various relationships between inflammatory markers and the other variables measured. Most notably, docosadienoic acid (C22:2n6c), docosapentaenoic acid (C22:5n3c), and folate were positively associated with numerous inflammatory parameters (P ≤ 0.05). Although no relationships were found between inflamm-aging and PPID, being positive for PPID was negatively associated with vitamin B12 (P ≤ 0.01). No relationships between inflammation and body composition were found. Even within this senior horse population, age was associated with multiple parameters, particularly with numerous inflammatory cytokines and fatty acids. In summary, inflamm-aging exhibited relationships with various other parameters examined, particularly with certain fatty acids. This exploratory study provides insights into physiological changes associated with inflamm-aging in the senior horse.

Leukocyte-derived ratios are associated with late-life any type dementia: a cross-sectional analysis of the Mugello study

Immunosenescence, vascular aging, and brain aging, all characterized by elevated levels of inflammatory markers, are thought to share a common pathogenetic pathway: inflamm-aging. Retrospective cross-sectional analysis was conducted using data from the Mugello study (Tuscany, Italy), a representative Italian cohort of free-living nonagenarians. to assess the association between specific peripheral inflammation markers derived from white blood cell counts, and the diagnosis of dementia. All the variables of interest were reported for 411 subjects (110 males and 301 females) out of 475 enrolled in the study. Anamnestic dementia diagnosis was obtained from clinical certificate and confirmed by a General Practitioner, whereas leukocyte ratios were directly calculated from white blood cell counts. Body mass index and comorbidities were considered potential confounders. Diagnosis of any type dementia was certified in 73 cases (17.8%). Subjects affected by dementia were older, more frequently reported a previous stroke, had lower body mass index, and lower Mini-Mental-State-Examination score. Moreover, they had a higher lymphocyte count and lymphocyte-to-monocyte ratio compared to the non-demented nonagenarians. We found that higher levels of lymphocyte counts are cross-sectionally associated with a clinical diagnosis of dementia. Furthermore, lymphocyte-to-monocyte ratio is directly associated with any type of dementia, independently of age, sex, lymphocyte count, and comorbidities. Lymphocyte-to-monocyte ratio may be considered a marker of immunological changes in the brain of dementia patients; moreover, it is low-cost, and easily available, thus enabling comparisons among different studies and populations, although the timeline and the extent of lymphocyte-to-monocyte ratio role in dementia development must be further investigated.

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.

A predicted unstructured C-terminal loop domain in SIRT1 is required for cathepsin B cleavage

The C-terminus of SIRT1 can be cleaved by cathepsin B at amino acid H533 to generate a lower-functioning, N-terminally intact 75 kDa polypeptide (75SIRT1) that might be involved in age-related pathologies. However, the mechanisms underlying cathepsin B docking to and cleavage of SIRT1 are unclear. Here, we first identified several 75SIRT1 variants that are augmented with aging correlatively with increased cathepsin B levels in various mouse tissues, highlighting the possible role of this cleavage event in age-related pathologies. Then, based on H533 point mutation and structural modeling, we generated a functionally intact ΔSIRT1 mutant, lacking the internal amino acids 528-543 (a predicted C-terminus loop domain), which exhibits resistance to cathepsin B cleavage in vitro and in cell cultures. Finally, we showed that cells expressing ΔSIRT1 under pro-inflammatory stress are more likely to undergo caspase 9- dependent apoptosis than those expressing 75SIRT1. Thus, our data suggest that the 15-amino acid predicted loop motif embedded in the C-terminus of SIRT1 is susceptible to proteolytic cleavage by cathepsin B, leading to the formation of several N-terminally intact SIRT1 truncated variants in various aging mouse tissues.This article has an associated First Person interview with the first author of the paper.

Binge ethanol exposure in advanced age elevates neuroinflammation and early indicators of neurodegeneration and cognitive impairment in female mice

Binge drinking is rising among aged adults (>65 years of age), however the contribution of alcohol misuse to neurodegenerative disease development is not well understood. Both advanced age and repeated binge ethanol exposure increase neuroinflammation, which is an important component of neurodegeneration and cognitive dysfunction. Surprisingly, the distinct effects of binge ethanol exposure on neuroinflammation and associated degeneration in the aged brain have not been well characterized. Here, we establish a model of intermittent binge ethanol exposure in young and aged female mice to investigate the effects of advanced age and binge ethanol on these outcomes. Following intermittent binge ethanol exposure, expression of pro-inflammatory mediators (tnf-α, il-1β, ccl2) was distinctly increased in isolated hippocampal tissue by the combination of advanced age and ethanol. Binge ethanol exposure also increased measures of senescence, the nod like receptor pyrin domain containing 3 (NLRP3) inflammasome, and microglia reactivity in the brains of aged mice compared to young. Binge ethanol exposure also promoted neuropathology in the hippocampus of aged mice, including tau hyperphosphorylation and neuronal death. We further identified advanced age-related deficits in contextual memory that were further negatively impacted by ethanol exposure. These data suggest binge drinking superimposed with advanced age promotes early markers of neurodegenerative disease development and cognitive decline, which may be driven by heightened neuroinflammatory responses to ethanol. Taken together, we propose this novel exposure model of intermittent binge ethanol can be used to identify therapeutic targets to prevent advanced age- and ethanol-related neurodegeneration.

Age-related dynamics of pro-inflammatory cytokines in equine bronchoalveolar lavage (BAL) fluid and peripheral blood from horses managed on pasture

The objectives of this study were to evaluate the natural age-related variation and compare the level of pro-inflammatory cytokines in the peripheral blood and lower airways of horses. The mRNA expression of IL-1β, IL-6, IL-8 TNF-α TLR-4 in bronchoalveolar lavage (BAL) fluid and peripheral blood mononuclear cells (PBMC) were studied by quantitative real time polymerase chain reaction (PCR) and differential cell count cytology from 44 horses of different ages. A significant age-related increase was found for the mRNA expression of IL-6, IL-8, TLR-4 and TNF-α in stimulated BAL cells and for TNF-α in stimulated PBMC. Furthermore, a significant decrease was found in the mRNA expression of IL-1β and TNF-α in stimulated BAL cells compared to stimulated PBMC. In conclusion, continued low antigen exposure of horses in the pasture environment could lead to a tight regulation of mRNA gene expression in the airway space compared to the peripheral blood and favour an age-related accumulation of mRNA genes.

Less functional variants of TLR-1/-6/-10 genes are associated with age

BACKGROUND

Determining the prerequisites for healthy aging is a major task in the modern world characterized by a longer lifespan of the individuals. Besides lifestyle and environmental influences genetic factors are involved as shown by several genome-wide association studies. Older individuals are known to have an impaired immune response, a condition recently termed "inflamm-aging". We hypothesize that the induction of this condition in the elderly is influenced by the sensitivity of the innate immune system. Therefore, we investigated genetic variants of the Toll-like receptor (TLR) family, one of the major family of innate immune receptors, for association with age in two cohorts of healthy, disease-free subjects.

RESULTS

According to sex we found a positive association of loss-of-function variants of TLR-1 and -6 with healthy aging with odds ratios of 1.54 in males for TLR-6 (249 S/S), and 1.41, 1.66, and 1.64 in females for TLR-1 prom., TLR-1 (248 S/S), and TLR-1 (602 S/S), respectively. Thus, the presence of these variants increases the probability of achieving healthy old age and indicates that a reduced TLR activity may be beneficial in the elderly.

CONCLUSIONS

This is the first report showing an association of TLR variants with age. While a loss of function of an important immune receptor may be a risk factor for acute infections as has been shown previously, in the setting of healthy ageing it appears to be protective, which may relate to "inflamm-aging". These first results should be reproduced in larger trials to confirm this hypothesis.

Unveiling the molecular basis of inflamm-aging induced by advanced glycation end products (AGEs)-modified human serum albumin (AGE-HSA) in patients with different immune-mediated diseases

Increased serum advanced glycation end products (AGEs) are commonly found in the patients with Diabetes mellitus (DM), aging-related diseases, and immune-mediated diseases. These diseases are notorious for vasculopathy, immune dysfunctions, and low-grade inflammation mimicking inflamm-aging. However, the molecular basis of inflamm-aging related to AGEs remains elucidation. In this study, we incubated human serum albumin (HSA) and glucose at 37 °C in 5% CO₂ incubator for 0-180 days to generate AGE-HSA. We found the mixture gradually changing the color from transparancy to brown color and increased molecular weight during incubation. The pH value also gradually decreased from 7.2 to 5.4 irrelevant to ionic charge or [Ca²⁺] concentration, but dependent on gradual glycation of the alkaline amino acids, lysine and arginine. Functionally, 40 μg/mL of AGE-HSA decreased IL-2 production from human Jurkat T cell line via suppressing p-STAT3, p-STAT4, and p-STAT6 with an increased tendency of senescence-associated β-galactosidase (SA-βgal) expression but irrelevant to change of Th1/Th2/Treg subpopulations. In contrast, AGE-HSA enhanced CC motif chemokine ligand 5 (CCL-5), IL-8, macrophage migration inhibitor factor (MIF), and interleukin 1 receptor antagonist (IL-1Ra) but suppressed SA-βgal expression by human macrophage-like THP-1 cells. Interestingly, AGE-HSA abrogated the HSA-induced soluble intercellular adhesion molecules 1 (sICAM-1), sE-selectin and endothelin release from human coronary artery endothelial cells (HCAEC) and enhanced SA-βgal expression. The accelerated and increased HSA glycations by individual inflammation-related cytokine such as IL-2, IL-6, IL-17, TGF-β, or TNF-α in the in vitro study reflect increased serum AGE levels in patients with immune-mediated diseases . In conclusion, AGE-HSA can exert immunosuppresive, inflammatory and vasculopathic effects mimicking inflamm-aging in these patients.

Safety and efficacy of autologous adipose tissue-derived stem cell transplantation in aging-related low-grade inflammation patients: a single-group, open-label, phase I clinical trial

BACKGROUND

Inflamm-aging is associated with the rate of aging and is significantly related to diseases such as Alzheimer's disease, Parkinson's disease, atherosclerosis, heart disease, and age-related degenerative diseases such as type II diabetes and osteoporosis. This study aims to evaluate the safety and efficiency of autologous adipose tissue-derived mesenchymal stem cell (AD-MSC) transplantation in aging-related low-grade inflammation patients.

METHODS

This study is a single-group, open-label, phase I clinical trial in which patients treated with 2 infusions (100 million cells i.v) of autologous AD-MSCs were initially evaluated in 12 inflamm-aging patients who concurrently had highly proinflammatory cytokines and 2 of the following 3 diseases: diabetes, dyslipidemia, and obesity. The treatment effects were evaluated based on plasma cytokines.

RESULTS

During the study's follow-up period, no adverse effects were observed in AD-MSC injection patients. Compared to baseline (D-44), the inflammatory cytokines IL-1α, IL-1β, IL-8, IL-6, and TNF-α were significantly reduced after 180 days (D180) of MSC infusion. IL-4/IL-10 at 90 days (D90) and IL-2/IL-10 at D180 increased, reversing the imbalance between proinflammatory and inflammatory ratios in the patients.

CONCLUSION

AD-MSCs represent a potential intervention to prevent age-related inflammation in patients.

TRIAL REGISTRATION

ClinicalTrials.gov number is NCT05827757, first registered on 13th Oct 2020.

Cutaneous burn injury induces neuroinflammation and reactive astrocyte activation in the hippocampus of aged mice

BACKGROUND

By 2050, one in six people globally will be 65 or older. Confusion and delirium are significant complications after burn injury, especially in the elderly population. The etiology is still unknown, however complications may be driven by pro-inflammatory activation of astrocytes within the hippocampus (HPC) after burn injury. Reduced levels of phosphorylated cyclic-AMP response binding element (pCREB), caused by elevated systemic pro-inflammatory cytokines, could lead to cognitive decline and memory impairment.

METHODS

To examine the effects of remote injury on neuroinflammation in advanced age, young and aged mice were subjected to a 15 % total body surface area scald burn or sham injury, and euthanized after 24 h. Expression of ccl2 and tnfa were measured by qPCR in the whole brain and HPC. Astrocyte activation was measured by immunofluorescence within the HPC. pCREB was measured by immunohistochemistry in the dentate gyrus.

RESULTS

We saw an 80-fold increase in ccl2 and a 30-fold elevation in tnfa after injury in the whole brain of aged mice compared to young groups and aged sham mice (p < 0.05 and p < 0.05, respectively). Additionally, there was a 30-fold increase in ccl2 within isolated HPC of aged injured mice when compared to sham injured animals (p < 0.05). When investigating specific HPC regions, immunofluorescence staining showed a >20 % rise in glial fibrillary acidic protein (GFAP) positive astrocytes within the cornu ammonis 3 (CA3) of aged injured mice when compared to all other groups (p < 0.05). Lastly, we observed a >20 % decrease in pCREB staining by immunohistochemistry in the dentate gyrus of aged mice compared to young regardless of injury (p < 0.05).

CONCLUSIONS

These novel data suggest that remote injury in aged, but not young, mice is associated with neuroinflammation and astrocyte activation within the HPC. These factors, paired with an age related reduction in pCREB, could help explain the increased cognitive decline seen in burn patients of advanced age. To our knowledge, we are the first group to examine the impact of advanced age combined with burn injury on inflammation and astrocyte activation within the brain.

TLR-6 SNP P249S is associated with healthy aging in nonsmoking Eastern European Caucasians - A cohort study

BACKGROUND

To investigate mechanisms that determine healthy aging is of major interest in the modern world marked by longer life expectancies. In addition to lifestyle and environmental factors genetic factors also play an important role in aging phenotypes. The aged immune system is characterized by a chronic micro-inflammation, known as inflamm-aging, that is suspected to trigger the onset of age-related diseases such as cardiovascular disease, Alzheimer's disease, cancer, and Diabetes Mellitus Type 2 (DMT2). We have recently shown that a Toll-like receptor 6 variant (P249S) is associated with susceptibility to cardiovascular disease and speculated that this variant may also be associated with healthy aging in general by decreasing the process of inflamm-aging.

RESULTS

Analyzing the PolSenior cohort we show here that nonsmoking S allele carriers are significantly protected from age-related diseases (P = 0.008, OR: 0.654). This association depends not only on the association with cardiovascular diseases (P = 0.018, OR: 0.483) for homozygous S allele carriers, but is also driven by a protection from Diabetes Mellitus type 2 (P = 0.010, OR: 0.486) for S allele carriers. In addition we detect a trend but no significant association of this allele with inflamm-aging in terms of baseline IL-6 levels.

CONCLUSION

We confirm our previous finding of the TLR-6 249S variant to be protective regarding cardiovascular diseases. Furthermore, we present first evidence of TLR-6 249S being involved in DMT2 susceptibility and may be in general associated with healthy aging possibly by reducing the process of inflamm-aging.

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

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

The biological roots of the sex-frailty paradox

Aging is a dynamic process that requires a continuous response and adaptation to internal and external stimuli over the life course. This eventually results in people aging differently and women aging differently than men. The "gender paradox" describes how women experience greater longevity than men, although linked with higher rates of disability and poor health status. Recently, the concept of frailty has been incorporated into this paradox giving rise to the "sex-frailty paradox" which describes how women are frailer because they manifest worse health status but, at the same time, appear less susceptible to death than men of the same age. However, very little is known about the biological roots of this sex-related difference in frailty. Inflamm-aging, the chronic low-grade inflammatory state associated with age, plays a key pathophysiological role in several age-related diseases/conditions, including Alzheimer's disease (AD), for which women have a higher lifetime risk than men. Interestingly, inflamm-aging develops at a different rate in women compared to men, with features that could play a critical role in the development of AD in women. According to this view, a continuum between aging and age-related diseases that probably lacks clear boundaries can be envisioned in which several shared biological mechanisms that progress at different pace may lead to different aging trajectories in women than in men. It, therefore, becomes urgent to consider a holistic approach in the study of aging, and decline it from a gender medicine perspective also considering the biological roots of the sex-frailty paradox.