The network and the remodeling theories of aging: historical background and new perspectives

The influence of inflammation and frailty in the aging continuum

Inflammaging is a low-grade inflammatory state that can be considered an adaptive process aimed at stimulating appropriate anti-inflammatory response. Frailty is determined by the accumulation of molecular and cellular defects accumulated throughout life; therefore, an appropriate frailty computation could be a valuable tool for measuring biological age. This study aims to analyse the association between inflammatory markers and both chronological age "per se" and frailty. We studied 452 persons aged 43-114 years. A Frailty Index (FI) was computed considering a wide range of age-related signs, symptoms, disabilities, and diseases. Plasma concentrations of inflammatory cytokines and peripheral markers of neuroinflammation were analysed by next-generation ELISA. The mean age of the cohort was 79.7 (from 43 to 114) years and the median FI was 0.19 (from 0.00 to 0.75). The concentrations of most inflammatory markers increased significantly with chronological age, after adjustment for sex and FI. Interferon-γ was significantly affected only by FI, while interleukin (IL)-10 and IL-1β were associated only with chronological age. In conclusion, we described different associations between inflammatory components and chronological vs. biological age. A better characterization of the molecular signature of aging could help to understand the complexity of this process.

The Role of the Kynurenine Pathway in the Pathophysiology of Frailty, Sarcopenia, and Osteoporosis

Tryptophan is an essential nutrient required to generate vitamin B3 (niacin), which is mainly involved in energy metabolism and DNA production. Alterations in tryptophan metabolism could have significant effects on aging and musculoskeletal health. The kynurenine pathway, essential in tryptophan catabolism, is modulated by inflammatory factors that are increased in older persons, a process known as inflammaging. Osteoporosis, sarcopenia, osteosarcopenia, and frailty have also been linked with chronically increased levels of inflammatory factors. Due to the disruption of the kynurenine pathway by chronic inflammation and/or changes in the gut microbiota, serum levels of toxic metabolites are increased and are associated with the pathophysiology of those conditions. In contrast, anabolic products of this pathway, such as picolinic acid, have demonstrated a positive effect on skeletal muscle and bone. In addition, physical activity can modulate this pathway by promoting the secretion of anabolic kynurenines. According to the evidence collected, kynurenines could have a promising role as biomarkers for osteoporosis sarcopenia, osteosarcopenia, and frailty in older persons. In addition, some of these metabolites could become important targets for developing new pharmacological treatments for these conditions.

The association of astrogliosis and microglial activation with aging and Alzheimer's disease pathology in the chimpanzee brain

Aging and neurodegenerative disorders, such as Alzheimer's disease (AD), trigger an immune response known as glial activation in the brain. Recent evidence indicates species differences in inflammatory responses to AD pathology, highlighting the need for additional comparative studies to further understand human-specific neuropathologies. In the present study, we report on the occurrence of astrogliosis, microglial activation, and their relationship with age and AD-like pathology in a cohort of male and female chimpanzees (Pan troglodytes). Chimpanzees with severe astrogliosis exhibited widespread upregulation of hypertrophic astrocytes immunoreactive for glial fibrillary acidic protein (GFAP) throughout all layers of the dorsolateral prefrontal cortex and a loss of the interlaminar palisade. In addition, extreme astrogliosis was associated with increased astrocyte density in the absence of significant microglial activation and AD lesions. A shift from decreased resting to increased phagocytotic microglia occurred with aging, although proliferation was absent and no changes in astrogliosis was observed. Vascular amyloid correlated with decreased astrocyte and microglia densities, while tau lesions were associated with morphological changes in microglia and greater total glia density and glia: neuron ratio. These results further our understanding of inflammatory processes within the chimpanzee brain and provide comparative data to improve our understanding of human aging and neuropathological processes.

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

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

Association between the Inflammatory Potential of the Diet and Biological Aging: A Cross-Sectional Analysis of 4510 Adults from the Moli-Sani Study Cohort

Chronological age (CA) may not accurately reflect the health status of an individual. Rather, biological age (BA) or hypothetical underlying "functional" age has been proposed as a relevant indicator of healthy aging. Observational studies have found that decelerated biological aging or Δage (BA-CA) is associated with a lower risk of disease and mortality. In general, CA is associated with low-grade inflammation, a condition linked to the risk of the incidence of disease and overall cause-specific mortality, and is modulated by diet. To address the hypothesis that diet-related inflammation is associated with Δage, a cross-sectional analysis of data from a sub-cohort from the Moli-sani Study (2005-2010, Italy) was performed. The inflammatory potential of the diet was measured using the Energy-adjusted Dietary Inflammatory Index (E-DII^TM) and a novel literature-based dietary inflammation score (DIS). A deep neural network approach based on circulating biomarkers was used to compute BA, and the resulting Δage was fit as the dependent variable. In 4510 participants (men 52.0%), the mean of CA (SD) was 55.6 y (±11.6), BA 54.8 y (±8.6), and Δage -0.77 (±7.7). In a multivariable-adjusted analysis, an increase in E-DII^TM and DIS scores led to an increase in Δage (β = 0.22; 95%CI 0.05, 0.38; β = 0.27; 95%CI 0.10, 0.44, respectively). We found interaction for DIS by sex and for E-DII^TM by BMI. In conclusion, a pro-inflammatory diet is associated with accelerated biological aging, which likely leads to an increased long-term risk of inflammation-related diseases and mortality.

Aging-Related Ovarian Failure and Infertility: Melatonin to the Rescue

Aging has a major detrimental effect on the optimal function of the ovary with changes in this organ preceding the age-related deterioration in other tissues, with the middle-aged shutdown leading to infertility. Reduced fertility and consequent inability to conceive by women in present-day societies who choose to have children later in life leads to increased frustration. Melatonin is known to have anti-aging properties related to its antioxidant and anti-inflammatory actions. Its higher follicular fluid levels relative to blood concentrations and its likely synthesis in the oocyte, granulosa, and luteal cells suggest that it is optimally positioned to interfere with age-associated deterioration of the ovary. Additionally, the end of the female reproductive span coincides with a significant reduction in endogenous melatonin levels. Thus, the aims are to review the literature indicating melatonin production in mitochondria of oocytes, granulosa cells, and luteal cells, identify the multiple processes underlying changes in the ovary, especially late in the cessation of the reproductive life span, summarize the physiological and molecular actions of melatonin in the maintenance of normal ovaries and in the aging ovaries, and integrate the acquired information into an explanation for considering melatonin in the treatment of age-related infertility. Use of supplemental melatonin may help preserve fertility later in life and alleviate frustration in women delaying childbearing age, reduce the necessity of in vitro fertilization–embryo transfer (IVF-ET) procedures, and help solve the progressively increasing problem of non-aging-related infertility in women throughout their reproductive life span. While additional research is needed to fully understand the effects of melatonin supplementation on potentially enhancing fertility, studies published to date suggest it may be a promising option for those struggling with infertility.

The Impact of Westernization on the Insulin/IGF-I Signaling Pathway and the Metabolic Syndrome: It Is Time for Change

The metabolic syndrome is a cluster of overlapping conditions resulting in an increased incidence of type 2 diabetes, cardiovascular disease, and cancer. In the last few decades, prevalence of the metabolic syndrome in the Western world has reached epidemic proportions and this is likely due to alterations in diet and the environment as well as decreased physical activity. This review discusses how the Western diet and lifestyle (Westernization) has played an important etiological role in the pathogenesis of the metabolic syndrome and its consequences by exerting negative effects on activity of the insulin-insulin-like growth factor-I (insulin-IGF-I) system. It is further proposed that interventions that normalize/reduce activity of the insulin-IGF-I system may play a key role in the prevention and treatment of the metabolic syndrome. For successful prevention, limitation, and treatment of the metabolic syndrome, the focus should be primarily on changing our diets and lifestyle in accordance with our genetic make-up, formed in adaptation to Paleolithic diets and lifestyles during a period of several million years of human evolution. Translating this insight into clinical practice, however, requires not only individual changes in our food and lifestyle, starting in pediatric populations at a very young age, but also requires fundamental changes in our current health systems and food industry. Change is needed: primary prevention of the metabolic syndrome should be made a political priority. New strategies and policies should be developed to stimulate and implement behaviors encouraging the sustainable use of healthy diets and lifestyles to prevent the metabolic syndrome before it develops.

A Comprehensive Analysis of Cytokine Network in Centenarians

Cytokines have been investigated extensively in elderly people, with conflicting results. We performed a comprehensive analysis of the plasma levels of 62 cytokines and growth factors involved in the regulation of the immune system, in healthy centenarians, and middle-aged controls. We confirmed the previously observed increase in the levels of several pro-inflammatory cytokines, such as TNF-α and IL-6, and found that several other cytokines, directly or indirectly involved in inflammation (such as IFN-α, IL-23, CCL-5), were present at higher levels in centenarians. We did not observe any increase in the levels of anti-inflammatory cytokines, with the notable exception of the Th2-shifting cytokine IL-19. No relevant difference was observed in cytokines regulating T cell immunity. Several growth factors having a role in regulating immunity, such as G-CSF, GM-CSF, EGF, and VEGF, were upregulated in centenarians, too. Principal component analysis of the cytokine dataset showed that pro and anti-inflammatory cytokines were the variables that contributed the most to the variability of the data we observed.

Towards AI-driven longevity research: An overview

While in the past technology has mostly been utilized to store information about the structural configuration of proteins and molecules for research and medical purposes, Artificial Intelligence is nowadays able to learn from the existing data how to predict and model properties and interactions, revealing important knowledge about complex biological processes, such as aging. Modern technologies, moreover, can rely on a broader set of information, including those derived from the next-generation sequencing (e.g., proteomics, lipidomics, and other omics), to understand the interactions between human body and the external environment. This is especially relevant as external factors have been shown to have a key role in aging. As the field of computational systems biology keeps improving and new biomarkers of aging are being developed, artificial intelligence promises to become a major ally of aging research.

Current Trends and Approaches to the Search for Genetic Determinants of Aging and Longevity

Aging is a natural process of extinction of the body and the main aspect that determines the life expectancy for individuals who have survived to the post-reproductive period. The process of aging is accompanied by certain physiological, immune, and metabolic changes in the body, as well as the development of age-related diseases. The contribution of genetic factors to human life expectancy is estimated at about 25-30%. Despite the success in identifying genes and metabolic pathways that may be involved in the life extension process in model organisms, the key question remains to what extent these data can be extrapolated to humans, for example, because of the complexity of its biological and sociocultural systems, as well as possible species differences in life expectancy and causes of mortality. New molecular genetic methods have significantly expanded the possibilities for searching for genetic factors of human life expectancy and identifying metabolic pathways of aging, the interaction of genes and transcription factors, the regulation of gene expression at the level of transcription, and epigenetic modifications. The review presents the latest research and current strategies for studying the genetic basis of human aging and longevity: the study of individual candidate genes in genetic population studies, variations identified by the GWAS method, immunogenetic differences in aging, and genomic studies to identify factors of "healthy aging." Understanding the mechanisms of the interaction between factors affecting the life expectancy and the possibility of their regulation can become the basis for developing comprehensive measures to achieve healthy longevity.

Supplementary Information

The online version contains supplementary material available at 10.1134/S1022795422120067.

Are Skeletal Muscle Changes during Prolonged Space Flights Similar to Those Experienced by Frail and Sarcopenic Older Adults?

Microgravity exposure causes several physiological and psychosocial alterations that challenge astronauts' health during space flight. Notably, many of these changes are mostly related to physical inactivity influencing different functional systems and organ biology, in particular the musculoskeletal system, dramatically resulting in aging-like phenotypes, such as those occurring in older persons on Earth. In this sense, sarcopenia, a syndrome characterized by the loss in muscle mass and strength due to skeletal muscle unloading, is undoubtedly one of the most critical aging-like adverse effects of microgravity and a prevalent problem in the geriatric population, still awaiting effective countermeasures. Therefore, there is an urgent demand to identify clinically relevant biological markers and to underline molecular mechanisms behind these effects that are still poorly understood. From this perspective, a lesson from Geroscience may help tailor interventions to counteract the adverse effects of microgravity. For instance, decades of studies in the field have demonstrated that in the older people, the clinical picture of sarcopenia remarkably overlaps (from a clinical and biological point of view) with that of frailty, primarily when referred to the physical function domain. Based on this premise, here we provide a deeper understanding of the biological mechanisms of sarcopenia and frailty, which in aging are often considered together, and how these converge with those observed in astronauts after space flight.

The Use of Retinal Microvascular Function and Telomere Length in Age and Blood Pressure Prediction in Individuals with Low Cardiovascular Risk

Ageing represents a major risk factor for many pathologies that limit human lifespan, including cardiovascular diseases. Biological ageing is a good biomarker to assess early individual risk for CVD. However, finding good measurements of biological ageing is an ongoing quest. This study aims to assess the use retinal microvascular function, separate or in combination with telomere length, as a predictor for age and systemic blood pressure in individuals with low cardiovascular risk. In all, 123 healthy participants with low cardiovascular risk were recruited and divided into three groups: group 1 (less than 30 years old), group 2 (31–50 years old) and group 3 (over 50 years old). Relative telomere length (RTL), parameters of retinal microvascular function, CVD circulatory markers and blood pressure (BP) were measured in all individuals. Symbolic regression- analysis was used to infer chronological age and systemic BP measurements using either RTL or a combination of RTL and parameters for retinal microvascular function. RTL decreased significantly with age (p = 0.010). There were also age-related differences between the study groups in retinal arterial time to maximum dilation (p = 0.005), maximum constriction (p = 0.007) and maximum constriction percentage (p = 0.010). In the youngest participants, the error between predicted versus actual values for the chronological age were smallest in the case of using both retinal vascular functions only (p = 0.039) or the combination of this parameter with RTL (p = 0.0045). Systolic BP was better predicted by RTL also only in younger individuals (p = 0.043). The assessment of retinal arterial vascular function is a better predictor than RTL for non-modifiable variables such as age, and only in younger individuals. In the same age group, RTL is better than microvascular function when inferring modifiable risk factors for CVDs. In older individuals, the accumulation of physiological and structural biological changes makes such predictions unreliable.

Senescence and cancer - role and therapeutic opportunities

Cellular senescence is a state of stable, terminal cell cycle arrest associated with various macromolecular changes and a hypersecretory, pro-inflammatory phenotype. Entry of cells into senescence can act as a barrier to tumorigenesis and, thus, could in principle constitute a desired outcome for any anticancer therapy. Paradoxically, studies published in the past decade have demonstrated that, in certain conditions and contexts, malignant and non-malignant cells with lastingly persistent senescence can acquire pro-tumorigenic properties. In this Review, we first discuss the major mechanisms involved in the antitumorigenic functions of senescent cells and then consider the cell-intrinsic and cell-extrinsic factors that participate in their switch towards a tumour-promoting role, providing an overview of major translational and emerging clinical findings. Finally, we comprehensively describe various senolytic and senomorphic therapies and their potential to benefit patients with cancer.

The entry of cells into senescence can act as a barrier to tumorigenesis; however, in certain contexts senescent malignant and non-malignant cells can acquire pro-tumorigenic properties. The authors of this Review discuss the cell-intrinsic and cell-extrinsic mechanisms involved in both the antitumorigenic and tumour-promoting roles of senescent cells, and describe the potential of various senolytic and senomorphic therapeutic approaches in oncology.

Cellular senescence is a natural barrier to tumorigenesis; senescent cells are widely detected in premalignant lesions from patients with cancer.

Cellular senescence is induced by anticancer therapy and can contribute to some treatment-related adverse events (TRAEs).

Senescent cells exert both protumorigenic and antitumorigenic effects via cell-autonomous and paracrine mechanisms.

Pharmacological modulation of senescence-associated phenotypes has the potential to improve therapy efficacy and reduce the incidence of TRAEs.

Living in endemic area for infectious diseases accelerates epigenetic age

Inflammaging is a low-grade inflammatory state generated by the aging process that can contribute to frailty and age-related diseases in the elderly. However, it can have distinct effects in the elderly living in endemic areas for infectious diseases. An increased inflammatory response may confer protection against infectious agents in these areas, although this advantage can cause accelerating epigenetic aging. In this study, we evaluated the inflammatory profile and the epigenetic age of infected and noninfected individuals from an endemic area in Brazil. The profile of cytokines, chemokines and growth factors analyzed in the sera of the two groups of individuals showed similarities, although infected individuals had a higher concentration of these mediators. A significant increase in IL-1ra, CXCL8, CCL2, CCL3 and CCL4 production was associated with leprosy infection. Notably, elderly individuals displayed distinct immune responses associated with their infection status when compared to adults suggesting an adaptive remodelling of their immune responses. Epigenetic analysis also showed that there was no difference in epigenetic age between the two groups of individuals. However, individuals from the endemic area had a significant accelerated aging when compared to individuals from São Paulo, a non-endemic area in Brazil. Moreover, the latter cohort was also epigenetically aged in relation to an Italian cohort. Our data shows that living in endemic areas for chronic infectious diseases results in remodelling of inflammaging and acceleration of epigenetic aging in individuals regardless of their infectious status. It also highlights that geographical, genetic and environmental factors influence aging and immunosenescence in their pace and profile.

Association Between Inflammation and Appetite in Healthy Community-Dwelling Older Adults—An enable Study

Aging is associated with reduced appetite as well as a slight increase in pro-inflammatory status, which both might contribute to the development of malnutrition. We aimed to evaluate the association between inflammation based on serum C-reactive protein (CRP), and appetite in healthy community-dwelling older adults. In this cross-sectional study of 158 healthy and non-smoking persons (aged 75–85 years), appetite was assessed in personal interviews by a single question with five answer categories. As nobody reported (very) poor appetite, the remaining three categories were dichotomised into “(very) good” and “moderate” appetite. Fasting serum CRP was analysed according to standard procedures, values ≥ 5.0 mg/L were considered as inflammation. The association between inflammation and appetite was examined by binary logistic regression, unadjusted and adjusted for age, sex, waist circumference, leptin, depressive mood, number of medications, interleukin-6 and tumor necrosis factor-α. Appetite was very good in 27.8%, good in 58.9%, and moderate in 13.3% of participants. Inflammation was present in 10.8% overall, in 8.8% of those with (very) good and in 23.8% of those with moderate appetite (p = 0.038). In the unadjusted model, participants with inflammation were 3.2 times more likely to have moderate appetite (95%CI: 1.01–10.44, p = 0.047). In the adjusted model, the odds of having moderate appetite was 3.7 times higher in participants with inflammation, but no longer significant (95%CI: 0.77–18.55, p = 0.102). In healthy older people, we found hints for a potential association between increased levels of CRP and a slightly reduced appetite. More studies in larger samples are needed.

Role of indoleamine 2,3-dioxygenase 1 (IDO1) and kynurenine pathway in the regulation of the aging process

Indoleamine 2,3-dioxygenase 1 (IDO1) is activated in chronic inflammatory states, e.g., in the aging process and age-related diseases. IDO1 enzyme catabolizes L-tryptophan (L-Trp) into kynurenine (KYN) thus stimulating the KYN pathway. The depletion of L-Trp inhibits the proliferation of immune cells in inflamed tissues and it also reduces serotonin synthesis predisposing to psychiatric disorders. Interestingly, IDO1 protein contains two immunoreceptor tyrosine-based inhibitory motifs (ITIM) which trigger suppressive signaling through the binding of PI3K p110 and SHP-1 proteins. This immunosuppressive activity is not dependent on the catalytic activity of IDO1. KYN and its metabolite, kynurenic acid (KYNA), are potent activators of the aryl hydrocarbon receptor (AhR) which can enhance immunosuppression. IDO1-KYN-AhR signaling counteracts excessive pro-inflammatory responses in acute inflammation but in chronic inflammatory states it has many harmful effects. A chronic low-grade inflammation is associated with the aging process, a state called inflammaging. There is substantial evidence that the activation of the IDO1-KYN-AhR pathway robustly increases with the aging process. The activation of IDO1-KYN-AhR signaling does not only suppress the functions of effector immune cells, probably promoting immunosenescence, but it also impairs autophagy, induces cellular senescence, and remodels the extracellular matrix as well as enhancing the development of osteoporosis and vascular diseases. I will review the function of IDO1-KYN-AhR signaling and discuss its activation with aging as an enhancer of the aging process.

Inflammaging and Brain: Curcumin and Its Beneficial Potential as Regulator of Microglia Activation

Inflammaging is a term used to describe the tight relationship between low-grade chronic inflammation and aging that occurs during physiological aging in the absence of evident infection. This condition has been linked to a broad spectrum of age-related disorders in various organs including the brain. Inflammaging represents a highly significant risk factor for the development and progression of age-related conditions, including neurodegenerative diseases which are characterized by the progressive dysfunction and degeneration of neurons in the brain and peripheral nervous system. Curcumin is a widely studied polyphenol isolated from Curcuma longa with a variety of pharmacologic properties. It is well-known for its healing properties and has been extensively used in Asian medicine to treat a variety of illness conditions. The number of studies that suggest beneficial effects of curcumin on brain pathologies and age-related diseases is increasing. Curcumin is able to inhibit the formation of reactive-oxygen species and other pro-inflammatory mediators that are believed to play a pivotal role in many age-related diseases. Curcumin has been recently proposed as a potential useful remedy against neurodegenerative disorders and brain ageing. In light of this, our current review aims to discuss the potential positive effects of Curcumin on the possibility to control inflammaging emphasizing the possible modulation of inflammaging processes in neurodegenerative diseases.

Dynamic Tests in Pituitary Endocrinology: Pitfalls in Interpretation during Aging

Aging and age-related diseases represent hot topics of current research. Progressive damage in morphology and function of cells and tissue characterizes the normal process of aging that is influenced by both genetic and environmental factors. The ability of each individual to adapt to these stressors defines the type of aging and the onset of age-related diseases (i.e., metabolic syndrome, inflammatory disorders, cancer, and neurodegenerative diseases). The endocrine system plays a critical role in this process because of its complex relationships with brain, immune system, and skeletal muscle; thus, alterations in hormonal networks occur during aging to maintain homeostasis, with consequent under- or overactivity of specific hypothalamic-pituitary-peripheral hormone axes. On the other hand, the increase in life expectancy has led to increasing incidence of age-related diseases, including endocrine disorders, which may prompt assessment of endocrine function in aging individuals. In this context, there is growing awareness that natural changes of endocrine physiology and physiopathology occurring with increasing age may necessitate age-driven diagnostic cutoffs requiring validation in the elderly. This review aims to analyze the available literature on the hormone response to the most important dynamic tests currently used in the clinical practice for the screening of anterior pituitary-related diseases to underline pitfalls in interpretation during aging.

Hypothalamic inflammation in metabolic disorders and aging

The hypothalamus is a critical brain region for the regulation of energy homeostasis. Over the years, studies on energy metabolism primarily focused on the neuronal component of the hypothalamus. Studies have recently uncovered the vital role of glial cells as an additional player in energy balance regulation. However, their inflammatory activation under metabolic stress condition contributes to various metabolic diseases. The recruitment of monocytes and macrophages in the hypothalamus helps sustain such inflammation and worsens the disease state. Neurons were found to actively participate in hypothalamic inflammatory response by transmitting signals to the surrounding non-neuronal cells. This activation of different cell types in the hypothalamus leads to chronic, low-grade inflammation, impairing energy balance and contributing to defective feeding habits, thermogenesis, and insulin and leptin signaling, eventually leading to metabolic disorders (i.e., diabetes, obesity, and hypertension). The hypothalamus is also responsible for the causation of systemic aging under metabolic stress. A better understanding of the multiple factors contributing to hypothalamic inflammation, the role of the different hypothalamic cells, and their crosstalks may help identify new therapeutic targets. In this review, we focus on the role of glial cells in establishing a cause-effect relationship between hypothalamic inflammation and the development of metabolic diseases. We also cover the role of other cell types and discuss the possibilities and challenges of targeting hypothalamic inflammation as a valid therapeutic approach.

Clustering Inflammatory Markers with Sociodemographic and Clinical Characteristics of Patients with Diabetes Type 2 Can Support Family Physicians' Clinical Reasoning by Reducing Patients' Complexity

Diabetes mellitus type 2 (DM2) is a complex disease associated with chronic inflammation, end-organ damage, and multiple comorbidities. Initiatives are emerging for a more personalized approach in managing DM2 patients. We hypothesized that by clustering inflammatory markers with variables indicating the sociodemographic and clinical contexts of patients with DM2, we could gain insights into the hidden phenotypes and the underlying pathophysiological backgrounds thereof. We applied the k-means algorithm and a total of 30 variables in a group of 174 primary care (PC) patients with DM2 aged 50 years and above and of both genders. We included some emerging markers of inflammation, specifically, neutrophil-to-lymphocyte ratio (NLR) and the cytokines IL-17A and IL-37. Multiple regression models were used to assess associations of inflammatory markers with other variables. Overall, we observed that the cytokines were more variable than the marker NLR. The set of inflammatory markers was needed to indicate the capacity of patients in the clusters for inflammatory cell recruitment from the circulation to the tissues, and subsequently for the progression of end-organ damage and vascular complications. The hypothalamus–pituitary–thyroid hormonal axis, in addition to the cytokine IL-37, may have a suppressive, inflammation-regulatory role. These results can help PC physicians with their clinical reasoning by reducing the complexity of diabetic patients.

Targeting Mediators of Inflammation in Heart Failure: A Short Synthesis of Experimental and Clinical Results

Inflammation has emerged as an important contributor to heart failure (HF) development and progression. Current research data highlight the diversity of immune cells, proteins, and signaling pathways involved in the pathogenesis and perpetuation of heart failure. Chronic inflammation is a major cardiovascular risk factor. Proinflammatory signaling molecules in HF initiate vicious cycles altering mitochondrial function and perturbing calcium homeostasis, therefore affecting myocardial contractility. Specific anti-inflammatory treatment represents a novel approach to prevent and slow HF progression. This review provides an update on the putative roles of inflammatory mediators involved in heart failure (tumor necrosis factor-alpha; interleukin 1, 6, 17, 18, 33) and currently available biological and non-biological therapy options targeting the aforementioned mediators and signaling pathways. We also highlight new treatment approaches based on the latest clinical and experimental research.

The Role of Insulin-like Growth Factor-1 (IGF-1) in the Control of Neuroendocrine Regulation of Growth

In mammals, the neuroendocrine system, which includes the communication between the hypothalamus and the pituitary, plays a major role in controlling body growth and cellular metabolism. GH produced from the pituitary somatotroph is considered the master regulator of somatic development and involved, directly and indirectly, in carbohydrate and lipid metabolism via complex, yet well-defined, signaling pathways. GH production from the pituitary gland is primarily regulated by the counter-regulatory effects of the hypothalamic GHRH and SST hormones. The role of IGF-1 feedback regulation in GH production has been demonstrated by pharmacologic interventions and in genetically modified mouse models. In the present review, we discuss the role of IGF-1 in the regulation of the GH-axis as it controls somatic growth and metabolic homeostasis. We present genetically modified mouse models that maintain the integrity of the GH/GHRH-axis with the single exception of IGF-1 receptor (IGF-1R) deficiency in the hypothalamic GHRH neurons and somatotroph that reveals a novel mechanism controlling adipose tissues physiology and energy expenditure.

Immunosuppressive network promotes immunosenescence associated with aging and chronic inflammatory conditions

The functional competence of the immune system gradually declines with aging, a process called immunosenescence. The age-related remodelling of the immune system affects both adaptive and innate immunity. In particular, a chronic low-grade inflammation, termed inflammaging, is associated with the aging process. Immunosenescence not only is present in inflammaging state, but it also occurs in several pathological conditions in conjunction with chronic inflammation. It is known that persistent inflammation stimulates a counteracting compensatory immunosuppression intended to protect host tissues. Inflammatory mediators enhance myelopoiesis and induce the generation of immature myeloid-derived suppressor cells (MDSC) which in mutual cooperation stimulates the immunosuppressive network. Immunosuppressive cells, especially MDSCs, regulatory T cells (Treg), and M2 macrophages produce immunosuppressive factors, e.g., TGF-β, IL-10, ROS, arginase-1 (ARG1), and indoleamine 2,3-dioxygenase (IDO), which suppress the functions of CD4/CD8T and B cells as well as macrophages, natural killer (NK) cells, and dendritic cells. The immunosuppressive armament (i) inhibits the development and proliferation of immune cells, (ii) decreases the cytotoxic activity of CD8T and NK cells, (iii) prevents antigen presentation and antibody production, and (iv) suppresses responsiveness to inflammatory mediators. These phenotypes are the hallmarks of immunosenescence. Immunosuppressive factors are able to control the chromatin landscape, and thus, it seems that the immunosenescence state is epigenetically regulated.

Feed-forward regulation between cellular senescence and immunosuppression promotes the aging process and age-related diseases

Aging is a progressive degenerative process involving a chronic low-grade inflammation and the accumulation of senescent cells. One major issue is to reveal the mechanisms which promote the deposition of pro-inflammatory senescent cells within tissues. The accumulation involves mechanisms which increase cellular senescence as well as those inhibiting the clearance of senescent cells from tissues. It is known that a persistent inflammatory state evokes a compensatory immunosuppression which inhibits pro-inflammatory processes by impairing the functions of effector immune cells, e.g., macrophages, T cells and natural killer (NK) cells. Unfortunately, these cells are indispensable for immune surveillance and the subsequent clearance of senescent cells, i.e., the inflammation-induced counteracting immunosuppression prevents the cleansing of host tissues. Moreover, senescent cells can also repress their own clearance by expressing inhibitors of immune surveillance and releasing the ligands of NKG2D receptors which impair their surveillance by NK and cytotoxic CD8⁺ T cells. It seems that cellular senescence and immunosuppression establish a feed-forward process which promotes the aging process and age-related diseases. I will examine in detail the immunosuppressive mechanisms which impair the surveillance and clearance of pro-inflammatory senescent cells with aging. In addition, I will discuss several therapeutic strategies to halt the degenerative feed-forward circuit associated with the aging process and age-related diseases.

Obesity and aging: Molecular mechanisms and therapeutic approaches

The epidemic of obesity is a major challenge for health policymakers due to its far-reaching effects on population health and potentially overwhelming financial burden on healthcare systems. Obesity is associated with an increased risk of developing acute and chronic diseases, including hypertension, stroke, myocardial infarction, cardiovascular disease, diabetes, and cancer. Interestingly, the metabolic dysregulation associated with obesity is similar to that observed in normal aging, and substantial evidence suggests the potential of obesity to accelerate aging. Therefore, understanding the mechanism of fat tissue dysfunction in obesity could provide insights into the processes that contribute to the metabolic dysfunction associated with the aging process. Here, we review the molecular and cellular mechanisms underlying both obesity and aging, and how obesity and aging can predispose individuals to chronic health complications. The potential of lifestyle and pharmacological interventions to counter obesity and obesity-related pathologies, as well as aging, is also addressed.

Dynamic and thermodynamic models of adaptation

The concept of biological adaptation was closely connected to some mathematical, engineering and physical ideas from the very beginning. Cannon in his "The wisdom of the body" (1932) systematically used the engineering vision of regulation. In 1938, Selye enriched this approach by the notion of adaptation energy. This term causes much debate when one takes it literally, as a physical quantity, i.e. a sort of energy. Selye did not use the language of mathematics systematically, but the formalization of his phenomenological theory in the spirit of thermodynamics was simple and led to verifiable predictions. In 1980s, the dynamics of correlation and variance in systems under adaptation to a load of environmental factors were studied and the universal effect in ensembles of systems under a load of similar factors was discovered: in a crisis, as a rule, even before the onset of obvious symptoms of stress, the correlation increases together with variance (and volatility). During 30 years, this effect has been supported by many observations of groups of humans, mice, trees, grassy plants, and on financial time series. In the last ten years, these results were supplemented by many new experiments, from gene networks in cardiology and oncology to dynamics of depression and clinical psychotherapy. Several systems of models were developed: the thermodynamic-like theory of adaptation of ensembles and several families of models of individual adaptation. Historically, the first group of models was based on Selye's concept of adaptation energy and used fitness estimates. Two other groups of models are based on the idea of hidden attractor bifurcation and on the advection-diffusion model for distribution of population in the space of physiological attributes. We explore this world of models and experiments, starting with classic works, with particular attention to the results of the last ten years and open questions.

Analysis of the levels of inflammatory parameters in persons over the age of 90

Chronic inflammatory conditions resulting from elevated levels of circulating proinflammatory mediators are common in the elderly. The aim of the paper was to analyze the balance between proinflammatory and anti-inflammatory markers in longevous individuals. The study was conducted in persons aged >90 years old, residents of Poland living either at home or staying at residential care facilities. The study included 90 persons (69 women and 21 men) aged between 90 and 103 years. Persons with abnormal CRP presented with a statistical tendency toward higher fibrinogen and lower IL10 and IL-1α levels compared to patients in whom CRP level was within the normal range. IL-6 concentration predicted abnormality within CRP. Inflammation in persons above the age of 90 years old might be linked to abnormal fibrinogen and IL-6 levels.

The Contextualized Genetics of Human Longevity: JACC Focus Seminar

The genetics of human longevity has long been studied, and in this regard, centenarians represent a very informative model. Centenarians are characterized by 2 main features: 1) the capability to avoid or postpone the major age-related diseases; and 2) a high level of heterogeneity of their phenotype. The first suggests that longevity and resistance to diseases are mediated by shared mechanisms, the latter that many strategies can be used to become long lived, likely as a result of variable genome-environment interactions. The authors suggest that the complexity of genome-environment interactions must be considered within an evolutionary and ecological perspective and that the concept of "risk allele" is highly context dependent, changing with age, time, and geography. Genes involved in both longevity and cardiovascular diseases, taken as a paradigmatic example of age-related diseases, as well as other emerging topics in genetics of longevity, such as micro-ribonucleic acid (miRNA) genetics, polygenic risk scores, environmental pollutants, and somatic mutations are discussed.

Inflammaging, hormesis and the rationale for anti-aging strategies

We propose in this review that hormesis, a concept profoundly and systematically addressed by Mark Mattson, has to be considered a sort of comprehensive "contact point" capable of unifying several conceptualizations of the aging process, including those focused on the stress response, oxidative stress and chronic inflammation/inflammaging. A major strength of hormesis and inflammaging is that they have a strong evolutionary basis. Moreover, both hormesis and inflammaging frame the aging process within a lifelong perspective of adaptation to different types of stresses. Such adaptation perspective also suggests that the aging process is malleable, and predicts that effective anti-aging strategies should mimic what evolution did in the course of million years and that we have to learn how to exploit the great potential inherent in the hormetic/inflammatory responses. To this regard, new topics such as the production of mitokines to cope with mitochondrial dysfunction are emerging as possible anti-aging target. This approach opens theoretically the door to the possibility of modulating the individual aging rate and trajectory by adopting the most effective scientifically-based lifestyle regarding fundamentally nutrition and physical activity. In this scenario Mark Mattson's lesson and personal example will permanently enlighten the aging field and the quest for a healthy aging and longevity.

Inflammaging in Endemic Areas for Infectious Diseases

Immunosenescence is marked by a systemic process named inflammaging along with a series of defects in the immunological activity that results in poor responses to infectious agents and to vaccination. Inflammaging, a state of low-grade chronic inflammation, usually leads to chronic inflammatory diseases and frailty in the elderly. However, some elderly escape from frailty and reach advanced age free of the consequences of inflammaging. This process has been called immunological remodeling, and it is the hallmark of healthy aging as described in the studies of centenarians in Italy. The biological markers of healthy aging are still a matter of debate, and the studies on the topic have focused on inflammatory versus remodeling processes and molecules. The sub-clinical inflammatory status associated with aging might be a deleterious event for populations living in countries where chronic infectious diseases are not prevalent. Nevertheless, in other parts of the world where they are, two possibilities may occur. Inflammatory responses may have a protective effect against these infectious agents. At the same time, the long-term consequences of protective immune responses during chronic infections may result in accelerated immunosenescence in these individuals. Therefore, the biological markers of healthy aging can vary according to environmental, cultural, and geographical settings that reflect worldwide, and in a non-biased, non-westernized perspective, the changes that we experience regarding our contacts with microorganisms and the outcomes of such contacts.

Aging and Chronic Liver Disease

Aging increases the incidence of chronic liver disease (CLD), worsens its prognosis, and represents the predominant risk factor for its development at all different stages. The hepatic sinusoid, which is fundamental for maintaining liver homeostasis, is composed by hepatocytes, liver sinusoidal endothelial cells, hepatic stellate cells, and hepatic macrophages. During CLD progression, hepatic cells suffer deregulations in their phenotype, which ultimately lead to disease development. The effects of aging on the hepatic sinusoid phenotype and function are not well understood, nevertheless, studies performed in experimental models of liver diseases and aging demonstrate alterations in all hepatic sinusoidal cells. This review provides an updated description of age-related changes in the hepatic sinusoid and discusses the implications for CLD development and treatment. Lastly, we propose aging as a novel therapeutic target to treat liver diseases and summarize the most promising therapies to prevent or improve CLD and extend healthspan.

Microbiomes other than the gut: inflammaging and age-related diseases

During the course of evolution, bacteria have developed an intimate relationship with humans colonizing specific body sites at the interface with the body exterior and invaginations such as nose, mouth, lung, gut, vagina, genito-urinary tract, and skin and thus constituting an integrated meta-organism. The final result has been a mutual adaptation and functional integration which confers significant advantages to humans and bacteria. The immune system of the host co-evolved with the microbiota to develop complex mechanisms to recognize and destroy invading microbes, while preserving its own bacteria. Composition and diversity of the microbiota change according to development and aging and contribute to humans' health and fitness by modulating the immune system response and inflammaging and vice versa. In the last decades, we experienced an explosion of studies on the role of gut microbiota in aging, age-related diseases, and longevity; however, less reports are present on the role of the microbiota at different body sites. In this review, we describe the key steps of the co-evolution between Homo sapiens and microbiome and how this adaptation can impact on immunosenescence and inflammaging. We briefly summarized the role of gut microbiota in aging and longevity while bringing out the involvement of the other microbiota.

Exosomal vesicles enhance immunosuppression in chronic inflammation: Impact in cellular senescence and the aging process

Exosomes represent an evolutionarily conserved signaling pathway which can act as an alarming mechanism in responses to diverse stresses, e.g. chronic inflammation activates the budding of exosomal vesicles in both immune and non-immune cells. Exosomes can contain both pro- and anti-inflammatory cargos but in chronic inflammation, exosomes mostly carry immunosuppressive cargos, e.g. enzymes and miRNAs. The aging process is associated with chronic low-grade inflammation and the accumulation of pro-inflammatory senescent cells into tissues. There is clear evidence that aging increases the number of exosomes in both the circulation and tissues. Especially, the secretion of immunosuppressive exosomes robustly increases from senescent cells. There are observations that the exosomes from senescent cells are involved in the expansion of senescence into neighbouring cells. Interestingly, the age-related exosomes contain immune suppressive cargos which enhance the immunosuppression within recipient immune cells, i.e. tissue-resident and recruited immune cells including M2 macrophages, myeloid-derived suppressor cells (MDSC), and regulatory T cells (Treg). It seems that increased immunosuppression with aging impairs the clearance of senescent cells and their accumulation within tissues augments the aging process.

Review on druggable targets of key age-associated properties regulated by therapeutic agents

Aging is a biological process which accounts for the deterioration of effective physiological functions. The malfunctioning of vital organ systems leads to the onset of neurodegenerative, cardiovascular, and immunomodulatory diseases in the elder population. Age-dependent mitochondrial dysfunctions trigger the production of reactive oxygen species, which serve as a major contributing factor for the onset of age-associated diseases. The increasing burden of age-related pathologies explicates the relevance of identifying novel therapeutic agents with enhanced potency and bioavailability. Key information on the biological mechanisms of significant age-related diseases aids in understanding relevant druggable targets essential for the initiation and progression of the disease. This review provides detailed insights into the druggable targets of key anti-aging properties of therapeutic agents such as anti-oxidant, immunomodulation, cardioprotection, anti-melanogenic, and anti-elastase properties. This information aids in the development of novel therapeutic agents/ supplements with enhanced efficacy.

PTSD and the klotho longevity gene: Evaluation of longitudinal effects on inflammation via DNA methylation

BACKGROUND

Longevity gene klotho (KL) is associated with age-related phenotypes including lifespan, cardiometabolic disorders, cognition, and brain morphology, in part, by conferring protection against inflammation. We hypothesized that the KL/inflammation association might be altered in the presence of psychiatric stress and operate via epigenetic pathways. We examined KL polymorphisms, and their interaction with posttraumatic stress disorder (PTSD) symptoms, in association with KL DNA methylation in blood. We further examined KL DNA methylation as a predictor of longitudinal changes in a peripheral biomarker of inflammation (C-reactive protein; CRP).

METHODS

The sample comprised 309 white non-Hispanic military veterans (93.5 % male; mean age: 32 years, range: 19-65; 30 % PTSD per structured diagnostic interview); 111 were reassessed approximately two years later.

RESULTS

Analyses revealed a methylation quantitative trait locus at rs9527025 (C370S, previously implicated in numerous studies of aging) in association with a Cytosine-phosphate-Guanine site (cg00129557; B = -.65, p =  1.29 X 10^-20), located within a DNase hypersensitivity site in the body of KL. There was also a rs9527025 x PTSD severity interaction (B = .004, p = .035) on methylation at this locus such that the minor allele was associated with reduced cg00129557 methylation in individuals with few or no PTSD symptoms while this effect was attenuated in those with elevated levels of PTSD. Path models revealed that methylation at cg00129557 was inversely associated with CRP over time (B = -.14, p = .005), controlling for baseline CRP. There was also an indirect effect of rs9527025 X PTSD on subsequent CRP via cg00129557 methylation (indirect B = -.002, p = .033).

CONCLUSIONS

Results contribute to our understanding of the epigenetic correlates of inflammation in PTSD and suggest that KL methylation may be a mechanism by which KL genotype confers risk vs. resilience to accelerated aging in those experiencing traumatic stress.

Influence of NAD+ as an ageing-related immunomodulator on COVID 19 infection: A hypothesis

The aging-associated decline of biological functions represents an important contributor to the increase in morbidity and mortality of human beings. Of these biological functions deterioration; there is a significant decline in the heart function, impairments in the lungs gas exchange, and impairments in the immune function. Many alterations in the body humeral and cellular immune response were observed with ageing process: The circulating pro-inflammatory cytokines are increased, the naive lymphocytes are decreased, the numbers of the antigen-presenting cells areelevated and the overall response is impaired. In addition, ageing is associated with a progressive restriction in the telomere length. Telomeres are located at chromosomes ends and play an essential role in preserving chromosome stability. Also, telomere length is very important to the immune system, because of the high sensitivity of the immune cells to the shortening of telomeres. Telomeres shortening adversely affect the immune cells' function and developments. These adverse changes increased the susceptibility for severe infection, risk of hospitalization, and even death. Elderly COVID-19 patients are at a real risk of complications due to impaired immune function, cytokine storm and defective respiratory function. Administration of anti-ageing immunomodulation factors like Nicotinamide Adenine Dinucleotide NAD+ can minimize these changes through its potent immunomodulation and longevity effects. NAD+ has a direct inhibitory effect on PARP-1 and can prevent pro-inflammatory cytokines over-activation. Increasing the NAD+ level will also result in stabilizing telomeres and this has a positive impact on immune cells function.

Thyroid hormones and frailty in persons experiencing extreme longevity

CONTEXT

The aging phenotype is quite heterogeneous, being the result of the capability of each individual to successfully or unsuccessfully response to stressors. The reduction of homeostatic reserve characterizing aging is accompanied by a remodeling of the endocrine system. Frailty has been indicated as a promising way for capturing the physiological decline as well as the biological aging of the individuals. In particular, the Frailty Index (FI), based on the assumption that health deficits tend to accumulate with aging, represents a quantitative measure of extreme interest.

OBJECTIVE

The study aims to correlate the thyroid hormone levels with FI in a population of centenarians and their offspring to capture the effects of thyroid remodeling in extreme longevity.

STUDY DESIGN

The study described 593 well-characterized Italian subjects, including 180 centenarians, as well as 276 centenarian's offspring and 137 age-matched controls.

RESULTS

FT3 levels and FT3/FT4 ratio were significantly lower (p < 0.001) and TSH levels higher (p < 0.001) in centenarians compared to the other groups, analysing both overall subjects and excluding subjects with hormone levels out of the normal ranges. In overall centenarians, we observed a negative correlation between FI and FT3 (ρ: -0.281, p < 0.001), FT3/FT4 (ρ: -0.344, p < 0.001) and TSH (ρ: -0.223, p 0.003) and a positive association between FI and FT4 (ρ: 0.189, p = 0.001). In centenarians with hormone levels within the normal ranges, similar negative correlations were observed between FI and FT3 (ρ: -0.201, p = 0.02) and FT3/FT4 (ρ: -0.264, p = 0.002). In this sub-analysis, FI positively correlated with FT4 and age (ρ: 0.167, p = 0.05; ρ: 0.219, p = 0.005, respectively). Conversely, no significant correlations were observed between hormone levels and FI in offspring and controls.

CONCLUSIONS

We found an association between thyroid hormone levels and frailty in centenarians, underlying the significant role of thyroid in the aging process and longevity.

Aging and Caloric Restriction Modulate the DNA Methylation Profile of the Ribosomal RNA Locus in Human and Rat Liver

A growing amount of evidence suggests that the downregulation of protein synthesis is an adaptive response during physiological aging, which positively contributes to longevity and can be modulated by nutritional interventions like caloric restriction (CR). The expression of ribosomal RNA (rRNA) is one of the main determinants of translational rate, and epigenetic modifications finely contribute to its regulation. Previous reports suggest that hypermethylation of ribosomal DNA (rDNA) locus occurs with aging, although with some species- and tissue- specificity. In the present study, we experimentally measured DNA methylation of three regions (the promoter, the 5′ of the 18S and the 5′ of 28S sequences) in the rDNA locus in liver tissues from rats at two, four, 10, and 18 months. We confirm previous findings, showing age-related hypermethylation, and describe, for the first time, that this gain in methylation also occurs in human hepatocytes. Furthermore, we show that age-related hypermethylation is enhanced in livers of rat upon CR at two and 10 months, and that at two months a trend towards the reduction of rRNA expression occurs. Collectively, our results suggest that CR modulates age-related regulation of methylation at the rDNA locus, thus providing an epigenetic readout of the pro-longevity effects of CR.

The Frailty Index in centenarians and their offspring

Frailty has been indicated as a way for capturing biological aging of the individual and Frailty Index (FI) may serve for this purpose. This study designed the FI in a cohort of centenarians, their offspring and control subjects sex- and age-matched with offspring. The FI mean value was 0.47 (SD 0.13) in centenarians, 0.15 (SD 0.12) in their offspring, and 0.22 (SD 0.14) in controls (p < 0.001). The difference between offspring and controls was statistically significant (p = 0.003). The correlation between FI and age was significant in offspring (r = 0.46, p < 0.001), close to significance in controls (r = 0.25, p = 0.08) and not significant in centenarians. Our study confirms that FI is a marker of biological age useful to discriminate different degrees of frailty even at extremely advanced age.

Genetics of Human Longevity Within an Eco-Evolutionary Nature-Nurture Framework

Human longevity is a complex trait, and to disentangle its basis has a great theoretical and practical consequences for biomedicine. The genetics of human longevity is still poorly understood despite several investigations that used different strategies and protocols. Here, we argue that such rather disappointing harvest is largely because of the extraordinary complexity of the longevity phenotype in humans. The capability to reach the extreme decades of human lifespan seems to be the result of an intriguing mixture of gene-environment interactions. Accordingly, the genetics of human longevity is here described as a highly context-dependent phenomenon, within a new integrated, ecological, and evolutionary perspective, and is presented as a dynamic process, both historically and individually. The available literature has been scrutinized within this perspective, paying particular attention to factors (sex, individual biography, family, population ancestry, social structure, economic status, and education, among others) that have been relatively neglected. The strength and limitations of the most powerful and used tools, such as genome-wide association study and whole-genome sequencing, have been discussed, focusing on prominently emerged genes and regions, such as apolipoprotein E, Forkhead box O3, interleukin 6, insulin-like growth factor-1, chromosome 9p21, 5q33.3, and somatic mutations among others. The major results of this approach suggest that (1) the genetics of longevity is highly population specific; (2) small-effect alleles, pleiotropy, and the complex allele timing likely play a major role; (3) genetic risk factors are age specific and need to be integrated in the light of the geroscience perspective; (4) a close relationship between genetics of longevity and genetics of age-related diseases (especially cardiovascular diseases) do exist. Finally, the urgent need of a global approach to the largely unexplored interactions between the 3 genetics of human body, that is, nuclear, mitochondrial, and microbiomes, is stressed. We surmise that the comprehensive approach here presented will help in increasing the above-mentioned harvest.

Vitamin D in physiological and pathological aging: Lesson from centenarians

Vitamin D is a secosteroid hormone that exerts a pleiotropic action on a wide spectrum of tissues, apparatuses and systems. Thus, vitamin D has assumed an increasingly dominant role as a key determinant of biological mechanisms and specific clinical conditions. Older people frequently present vitamin D deficiency, a status potentially influencing several mechanisms responsible for different age-related diseases. Centenarians symbolize the ideal model for investigating the peculiar traits of longevity, as they have reached an age close to the estimated limit of the human lifespan. Interestingly, despite the profound heterogeneity of centenarians in terms of health status, all these people share the same condition of severe vitamin D deficiency, suggesting that they may have implemented a number of adaptive strategies to cope with the age-related physiological derangement of vitamin D metabolism. The lesson deriving from centenarians' experience suggests that: i) severe vitamin D deficiency does not preclude the possibility of reaching extreme longevity, ii) strategies to prevent hypovitaminosis D may be useful to slow down the processes of "fragilization" occurring in aged people, iii) beneficial effects of vitamin D supplementation need to be confirmed regarding longevity.

Age-associated antigen-presenting cell alterations promote dry-eye inducing Th1 cells

Aging is a significant risk factor for dry eye. Here we used a murine aging model to investigate the effects of aging on antigen presenting cells (APCs) and generation of pathogenic T helper (Th)-1 cells. Our results showed that APCs from aged mice accumulate at the conjunctiva, have higher levels of co-activation marker CD86 and lower aldehyde dehydrogenase activity. Using topical ovalbumin peptide as a surrogate antigen, we observed an increased number of antigen-loaded APCs in the draining cervical lymph nodes in the aged group and loss of tight junction protein occludin in the conjunctiva. Aged cervical lymph nodes APCs showed a greater generation of Th1 cells than young APCs in antigen-presentation assays in vitro. Aged lacrimal glands, and draining nodes showed an accumulation of IFN-γ producing CD4+T cells, while Th-17 cells were present only in aged draining nodes. There was also an age-related increase in CD4+CXCR3+IFN-γ+ cells in the conjunctiva, nodes, and lacrimal glands while CD4+CCR6+IL-17A+ cells increased in the draining nodes of aged mice. Adoptive transfer of aged CD4+CXCR3+ cells into young, naive immunodeficient recipients caused greater goblet cell loss than young CD4+CXCR3+ donor cells. Our results demonstrate that age-associated changes in APCs are critical for the pathogenesis of age-related dry eye.

Gender-Specific Differences in Concentrations of Biochemical Parameters in Persons over the Age of 90

The ageing process is a phenomenon leading to an emergence of a web of interrelated biological processes producing significant changes in the human body. The aim of the paper was to analyse gender-specific differences with regard to selected biochemical parameters in longevity. The study was conducted in Poland in 2017. The study population comprised of long-lived individuals, both living at home and staying at residential care homes. There were 90 people of both genders (69 women and 21 men) aged between 90 and 103 years (mean = 92.36; SD = 2.98). The biochemical markers of longevity in the studied patients were identified by assessing their pro-inflammatory and anti-inflammatory status in various metabolic aspects. The analysis of biochemical variables revealed numerous statistically significant differences, both in the study group as a whole and between the genders. The ageing process is extremely complex, but understanding it will allow for a real intervention in life extension. Research into the processes involved in ageing and longevity will enable a better understanding of the mechanisms responsible for them, and to enjoy those processes in good health.

AMPK activation inhibits the functions of myeloid-derived suppressor cells (MDSC): impact on cancer and aging

AMP-activated protein kinase (AMPK) has a crucial role not only in the regulation of tissue energy metabolism but it can also control immune responses through its cooperation with immune signaling pathways, thus affecting immunometabolism and the functions of immune cells. It is known that AMPK signaling inhibits the activity of the NF-κB system and thus suppresses pro-inflammatory responses. Interestingly, AMPK activation can inhibit several major immune signaling pathways, e.g., the JAK-STAT, NF-κB, C/EBPβ, CHOP, and HIF-1α pathways, which induce the expansion and activation of myeloid-derived suppressor cells (MDSC). MDSCs induce an immunosuppressive microenvironment in tumors and thus allow the escape of tumor cells from immune surveillance. Chronic inflammation has a key role in the expansion and activation of MDSCs in both tumors and inflammatory disorders. The numbers of MDSCs also significantly increase during the aging process concurrently with the immunosenescence associated with chronic low-grade inflammation. Increased fatty acid oxidation and lactate produced by aerobic glycolysis are important immunometabolic enhancers of MDSC functions. However, it seems that AMPK signaling regulates the functions of MDSCs in a context-dependent manner. Currently, the activators of AMPK signaling are promising drug candidates for cancer therapy and possibly for the extension of healthspan and lifespan. We will describe in detail the AMPK-mediated regulation of the signaling pathways controlling the expansion and activation of immunosuppressive MDSCs. We will propose that the beneficial effects mediated by AMPK activation, e.g., in cancers and the aging process, could be induced by the inhibition of MDSC functions.

Elevated Inflammatory Status and Increased Risk of Chronic Disease in Chronological Aging: Inflamm-aging or Inflamm-inactivity?

Age-associated hyper-inflammation or "inflamm-aging" has been linked to the development of chronic diseases and characterized as an unavoidable aspect of aging. However, the inflamm-aging model does not adequately address the potential anti-inflammatory effects of exercise training and the potential for exercise to ameliorate several age-related diseases. In this brief review, we introduce a new paradigm-inflamm-inactivity-that describes a potent counter-measure to age-associated inflammatory illness.

Lifelong aerobic exercise protects against inflammaging and cancer

Biological aging is associated with progressive damage accumulation, loss of organ reserves, and systemic inflammation ('inflammaging'), which predispose for a wide spectrum of chronic diseases, including several types of cancer. In contrast, aerobic exercise training (AET) reduces inflammation, lowers all-cause mortality, and enhances both health and lifespan. In this study, we examined the benefits of early-onset, lifelong AET on predictors of health, inflammation, and cancer incidence in a naturally aging mouse model (C57BL/J6). Lifelong, voluntary wheel-running (O-AET; 26-month-old) prevented age-related declines in aerobic fitness and motor coordination vs. age-matched, sedentary controls (O-SED). AET also provided partial protection against sarcopenia, dynapenia, testicular atrophy, and overall organ pathology, hence augmenting the 'physiologic reserve' of lifelong runners. Systemic inflammation, as evidenced by a chronic elevation in 17 of 18 pro- and anti-inflammatory cytokines and chemokines (P < 0.05 O-SED vs. 2-month-old Y-CON), was potently mitigated by lifelong AET (P < 0.05 O-AET vs. O-SED), including master regulators of the cytokine cascade and cancer progression (IL-1β, TNF-α, and IL-6). In addition, circulating SPARC, previously known to be upregulated in metabolic disease, was elevated in old, sedentary mice, but was normalized to young control levels in lifelong runners. Remarkably, malignant tumours were also completely absent in the O-AET group, whereas they were present in the brain (pituitary), liver, spleen, and intestines of sedentary mice. Collectively, our results indicate that early-onset, lifelong running dampens inflammaging, protects against multiple cancer types, and extends healthspan of naturally-aged mice.

ROLE of IGF-1 System in the Modulation of Longevity: Controversies and New Insights From a Centenarians' Perspective

Human aging is currently defined as a physiological decline of biological functions in the body with a continual adaptation to internal and external damaging. The endocrine system plays a major role in orchestrating cellular interactions, metabolism, growth, and aging. Several in vivo studies from worms to mice showed that downregulated activity of the GH/IGF-1/insulin pathway could be beneficial for the extension of human life span, whereas results are contradictory in humans. In the present review, we discuss the potential role of the IGF-1 system in modulation of longevity, hypothesizing that the endocrine and metabolic adaptation observed in centenarians and in mammals during caloric restriction may be a physiological strategy for extending lifespan through a slower cell growing/metabolism, a better physiologic reserve capacity, a shift of cellular metabolism from cell proliferation to repair activities and a decrease in accumulation of senescent cells. Therefore, understanding of the link between IGF-1/insulin system and longevity may have future clinical applications in promoting healthy aging and in Rehabilitation Medicine.

Trajectories of inflammatory biomarkers over the eighth decade and their associations with immune cell profiles and epigenetic ageing

BACKGROUND

Epigenetic age acceleration (an older methylation age compared to chronological age) correlates strongly with various age-related morbidities and mortality. Chronic systemic inflammation is thought to be a hallmark of ageing, but the relationship between an increased epigenetic age and this likely key phenotype of ageing has not yet been extensively investigated.

METHODS

We modelled the trajectories of the inflammatory biomarkers C-reactive protein (CRP; measured using both a high- and low-sensitivity assay) and interleukin-6 (IL-6) over the eighth decade in the Lothian Birth Cohort 1936. Using linear mixed models, we investigated the association between CRP and immune cell profiles imputed from the methylation data and examined the cross-sectional and longitudinal association between the inflammatory biomarkers and two measures of epigenetic age acceleration, derived from the Horvath and Hannum epigenetic clocks.

RESULTS

We found that low-sensitivity CRP declined, high-sensitivity CRP did not change, and IL-6 increased over time within the cohort. CRP levels inversely associated with CD8+T cells and CD4+T cells and positively associated with senescent CD8+T cells, plasmablasts and granulocytes. Cross-sectionally, the Hannum, but not the Horvath, measure of age acceleration was positively associated with each of the inflammatory biomarkers, including a restricted measure of CRP (≤ 10 mg/L) likely reflecting levels relevant to chronic inflammation.

CONCLUSIONS

We found a divergent relationship between inflammation and immune system parameters in older age. We additionally report the Hannum measure of epigenetic age acceleration associated with an elevated inflammatory profile cross-sectionally, but not longitudinally.

The role of myeloid-derived suppressor cells (MDSC) in the inflammaging process

A chronic low-grade inflammation is one of the hallmarks of the aging process. This gradually augmenting inflammatory state has been termed inflammaging. Inflammaging is associated with increased myelopoiesis in the bone marrow. This myelopoiesis-biased process increases the generation not only of mature myeloid cells, e.g. monocytes, macrophages, and neutrophils, but also immature myeloid progenitors and myeloid-derived suppressor cells (MDSCs). It is known that the aging process is associated with a significant increase in the presence of MDSCs in the bone marrow, blood, spleen, and peripheral lymph nodes. Consequently, MDSCs will become recruited into inflamed tissues where they suppress acute inflammatory responses and trigger the resolution of inflammation. However, if the perpetrator cannot be eliminated, the long-term presence of MDSCs suppresses the host's immune defence and increases the susceptibility to infections and tumorigenesis. Chronic immunosuppression also impairs the clearance of waste products and dead cells, impairs energy metabolism, and disturbs tissue proteostasis. This immunosuppressive state is reminiscent of the immunosenescence observed in inflammaging. It seems that proinflammatory changes in tissues with aging stimulate the myelopoietic production of MDSCs which subsequently induces immunosenescence and maintains the chronic inflammaging process. We will briefly describe the functions of MDSCs and then examine in detail how inflammaging enhances the generation MDSCs and how MDSCs are involved in the control of immunosenescence occurring in inflammaging.