Lifestyle exercise attenuates immunosenescence; flow cytometry analysis

Metabolic pathways in immune senescence and inflammaging: Novel therapeutic strategy for chronic inflammatory lung diseases. An EAACI position paper from the Task Force for Immunopharmacology

The accumulation of senescent cells drives inflammaging and increases morbidity of chronic inflammatory lung diseases. Immune responses are built upon dynamic changes in cell metabolism that supply energy and substrates for cell proliferation, differentiation, and activation. Metabolic changes imposed by environmental stress and inflammation on immune cells and tissue microenvironment are thus chiefly involved in the pathophysiology of allergic and other immune-driven diseases. Altered cell metabolism is also a hallmark of cell senescence, a condition characterized by loss of proliferative activity in cells that remain metabolically active. Accelerated senescence can be triggered by acute or chronic stress and inflammatory responses. In contrast, replicative senescence occurs as part of the physiological aging process and has protective roles in cancer surveillance and wound healing. Importantly, cell senescence can also change or hamper response to diverse therapeutic treatments. Understanding the metabolic pathways of senescence in immune and structural cells is therefore critical to detect, prevent, or revert detrimental aspects of senescence-related immunopathology, by developing specific diagnostics and targeted therapies. In this paper, we review the main changes and metabolic alterations occurring in senescent immune cells (macrophages, B cells, T cells). Subsequently, we present the metabolic footprints described in translational studies in patients with chronic asthma and chronic obstructive pulmonary disease (COPD), and review the ongoing preclinical studies and clinical trials of therapeutic approaches aiming at targeting metabolic pathways to antagonize pathological senescence. Because this is a recently emerging field in allergy and clinical immunology, a better understanding of the metabolic profile of the complex landscape of cell senescence is needed. The progress achieved so far is already providing opportunities for new therapies, as well as for strategies aimed at disease prevention and supporting healthy aging.

Cellular senescence in acute kidney injury: Target and opportunity

Acute kidney injury (AKI) is a common clinical disease with a high incidence and mortality rate. It typically arises from hemodynamic alterations, sepsis, contrast agents, and toxic drugs, instigating a series of events that culminate in tissue and renal damage. This sequence of processes often leads to acute renal impairment, prompting the initiation of a repair response. Cellular senescence is an irreversible arrest of the cell cycle. Studies have shown that renal cellular senescence is closely associated with AKI through several mechanisms, including the promotion of oxidative stress and inflammatory response, telomere shortening, and the down-regulation of klotho expression. Exploring the role of cellular senescence in AKI provides innovative therapeutic ideas for both the prevention and treatment of AKI. Furthermore, it has been observed that targeted removal of senescent cells in vivo can efficiently postpone senescence, resulting in an enhanced prognosis for diseases associated with senescence. This article explores the effects of common anti-senescence drugs senolytics and senostatic and lifestyle interventions on renal diseases, and mentions the rapid development of mesenchymal stem cells (MSCs). These studies have taken senescence-related research to a new level. Overall, this article comprehensively summarizes the studies on cellular senescence in AKI, aiming is to elucidate the relationship between cellular senescence and AKI, and explore treatment strategies to improve the prognosis of AKI.

Sports and Immunity, from the recreational to the elite athlete

The pivotal role of the immune system in physical activity is well-established. While interactions are complex, they tend to constitute discrete immune responses. Moderate intensity exercise causes leukocytosis with a mild anti-inflammatory cytokine profile and immunoenhancement. Above a threshold of intensity, lactate-mediated IL-6 release causes a proinflammatory state followed by a depressed inflammatory state, which stimulates immune adaptation and longer term cardiometabolic enhancement. Exercise-related immune responses are modulated by sex, age and immunonutrition. At all ability levels, these factors collectively affect the immune balance between enhancement or overload and dysfunction. Excessive training, mental stress or insufficient recovery risks immune cell exhaustion and hypothalamic pituitary axis (HPA) stress responses causing immunodepression with negative impacts on performance or general health. Participation in sport provides additional immune benefits in terms of ensuring regularity, social inclusion, mental well-being and healthier life choices in terms of diet and reduced smoking and alcohol, thereby consolidating healthy lifestyles and longer term health. Significant differences exist between recreational and professional athletes in terms of inherent characteristics, training resilience and additional stresses arising from competition schedules, travel-related infections and stress. Exercise immunology examines the central role of immunity in exercise physiology and straddles multiple disciplines ranging from neuroendocrinology to nutrition and genetics, with the aim of guiding athletes to train optimally and safely. This review provides a brief outline of the main interactions of immunity and exercise, some influencing factors, and current guidance on maintaining immune health.

Does excess body weight accelerate immune aging?

BACKGROUND

Overweight and obesity in older adults increase the risk of a range of comorbidities by sustaining chronic inflammation and thus enhancing immunosenescence. This study aimed to assess whether excess body mass affected disproportion in T lymphocytes. Therefore, the study was designed to explain whether excess body mass in older individuals affected the disproportion in numbers of T lymphocytes and whether anthropometric indices and immune risk profile expressed as CD4/CD8 ratio are diagnostically useful in the analysis of immunosenescence.

MATERIALS & METHODS

One hundred three individuals aged 73.6 ± 3.1 years were allocated to the normal body mass (body mass index (BMI) 18.5-24.9 kg/m2,n = 39), the pre-obesity (BMI 25.0-29.9 kg/m2, n = 44) or the obesity (BMI ≥30.0 kg/m2, n = 20) group, based on WHO recommendations. Details on the subjects' medical history and lifestyle were obtained by health questionnaire. Anthropometric analysis was performed by bioelectrical impedance method, biochemical analysis was made by the automatic analyzer and ELISA immunoassays, and T and B lymphocyte counts were determined by eight-parameter flow cytometry. Additionally, visceral adiposity index, body adiposity index (BAI), and body shape index (ABSI) were evaluated based on body circumference, BMI and lipid-lipoprotein profile measurements.

RESULTS

The highest percentage of CD3+CD4+ T lymphocytes (59.4 ± 12.6 %) and the lowest CD3+CD8+ T lymphocytes (31.6 ± 10.0 %) were noted in patients the obesity group. The highest cut-off value of 1.9 for CD4/CD8 ratio was recorded in the normal body mass vs pre-obesity model. CD4/CD8 ratio > 2.5 was recorded in >20 % of our pre-obesity and obesity groups while 64.5 % of the normal body mass group had CD4/CD8 ratio < 1. High diagnostic usefulness was demonstrated for both BAI and lipid accumulation product (LAP) (AUC values of ~0.800 and ~ 0.900 respectively) in three models: normal body mass vs pre-obesity, normal body mass vs obesity, and pre-obesity vs obesity.

CONCLUSION

The odds ratios (OR) for CD4/CD8 ratio in the normal body mass vs obesity model (OR = 16.1, 95%CI 3.8-93.6) indicated a potential diagnostic value of T lymphocytes for clinical prognosis of immune aging in relation to excess body weight in older adults. High values of AUC obtained for the following models: CD4/CD8 + BAI (AUC = 0.927), CD4/CD8 + LAP (AUC = 1.00), CD4/CD8 + ABSI (AUC = 0.865) proved to provide excellent discrimination between older adults with obesity and with normal body mass.

The association between the CD4/CD8 ratio and surgical site infection risk among HIV-positive adults: insights from a China hospital

Purpose

It is well known that the CD4/CD8 ratio is a special immune-inflammation marker. We aimed to explore the relationship between the CD4/CD8 ratio and the risk of surgical site infections (SSI) among human immunodeficiency virus (HIV)-positive adults undergoing orthopedic surgery.

Methods

We collected and analyzed data from 216 HIV-positive patients diagnosed with fractures at the department of orthopedics, Beijing Ditan Hospital between 2011 and 2019. The demographic, surgical, and hematological data for all patients were collected in this retrospective cohort study. We explored the risk factors for SSI using univariate and multivariate logistic regression analysis. Then, the clinical correlation between the CD4 count, CD4/CD8 ratio, and SSI was studied using multivariate logistic regression models after adjusting for potential confounders. Furthermore, the association between the CD4/CD8 ratio and SSI was evaluated on a continuous scale with restricted cubic spline (RCS) curves based on logistic regression models.

Results

A total of 23 (10.65%) patients developed SSI during the perioperative period. Patients with hepatopathy (OR=6.10, 95%CI=1.46-28.9), HIV viral load (OR=8.68, 95%CI=1.42-70.2; OR=19.4, 95%CI=3.09-179), operation time (OR=7.84, 95%CI=1.35-77.9), and CD4 count (OR=0.05, 95%CI=0.01-0.23) were risk factors for SSI (P-value < 0.05). Our study demonstrated that a linear relationship between CD4 count and surgical site infection risk. In other words, patients with lower CD4 counts had a higher risk of developing SSI. Furthermore, the relationship between CD4/CD8 ratio and SSI risk was non-linear, inverse 'S' shaped. The risk of SSI increased substantially when the ratio was below 0.913; above 0.913, the risk of SSI was almost unchanged. And there is a 'threshold-saturation' effect between them.

Conclusion

Our research shows the CD4/CD8 ratio could be a useful predictor and immune-inflammation marker of the risk of SSI in HIV-positive fracture patients. These results, from a Chinese hospital, support the beneficial role of immune reconstitution in HIV-positive patients prior to orthopedic surgery.

Immune cell status, cardiorespiratory fitness and body composition among breast cancer survivors and healthy women: a cross sectional study

Methods: We examined whether immune cell profiles differ between healthy women (n = 38) and breast cancer survivors (n = 27) within 2 years of treatment, and whether any group-differences were influenced by age, cytomegalovirus infection, cardiorespiratory fitness and body composition. Using flow cytometry, CD4+ and CD8+ T cell subsets, including naïve (NA), central memory (CM) and effector cells (EM and EMRA) were identified using CD27/CD45RA. Activation was measured by HLA-DR expression. Stem cell-like memory T cells (TSCMs) were identified using CD95/CD127. B cells, including plasmablasts, memory, immature and naïve cells were identified using CD19/CD27/CD38/CD10. Effector and regulatory Natural Killer cells were identified using CD56/CD16. Results: Compared to healthy women, CD4+ CM were +Δ21% higher among survivors (p = 0.028) and CD8+ NA were -Δ25% lower (p = 0.034). Across CD4+ and CD8+ subsets, the proportion of activated (HLA-DR+) cells was +Δ31% higher among survivors: CD4+ CM (+Δ25%), CD4+ EM (+Δ32%) and CD4+ EMRA (+Δ43%), total CD8⁺ (+Δ30%), CD8+ EM (+Δ30%) and CD8+ EMRA (+Δ25%) (p < 0.046). The counts of immature B cells, NK cells and CD16+ NK effector cells were higher among survivors (+Δ100%, +Δ108% and +Δ143% respectively, p < 0.04). Subsequent analyses examined whether statistically significant differences in participant characteristics, influenced immunological differences between groups. Compared to healthy women, survivors were older (56 ± 6 y vs. 45 ± 11 y), had lower cardiorespiratory fitness (V˙O2max mL kg^-1 min^-1: 28.8 ± 5.0 vs. 36.2 ± 8.5), lower lean mass (42.3 ± 5.0 kg vs. 48.4 ± 15.8 kg), higher body fat (36.3% ± 5.3% vs. 32.7% ± 6.4%) and higher fat mass index (FMI kg/m²: 9.5 ± 2.2 vs. 8.1 ± 2.7) (all p < 0.033). Analysis of covariance revealed divergent moderating effects of age, CMV serostatus, cardiorespiratory fitness and body composition on the differences in immune cell profiles between groups, depending on the cell type examined. Moreover, across all participants, fat mass index was positively associated with the proportion of HLA-DR+ CD4+ EMRA and CD8+ EM/EMRA T cells (Pearson correlation: r > 0.305, p < 0.019). The association between fat mass index and HLA-DR+ CD8+ EMRA T cells withstood statistical adjustment for all variables, including age, CMV serostatus, lean mass and cardiorespiratory fitness, potentially implicating these cells as contributors to inflammatory/immune-dysfunction in overweight/obesity.

The effects of exercise training for eight weeks on immune cell characteristics among breast cancer survivors

Methods

This study examined the effects of exercise training for 8 weeks on blood immune cell characteristics among 20 breast cancer survivors (age 56 ± 6 years, Body Mass Index 25.4 ± 3.0 kg m²) within two years of treatment. Participants were randomly allocated to a partly-supervised or a remotely-supported exercise group (n = 10 each). The partly supervised group undertook 2 supervised (laboratory-based treadmill walking and cycling) and 1 unsupervised session per week (outdoor walking) progressing from 35 to 50 min and 55% to 70% V˙O₂max. The remotely-supported group received weekly exercise/outdoor walking targets (progressing from 105 to 150 min per week 55% to 70% V˙O₂max) via weekly telephone calls discussing data from a fitness tracker. Immune cell counts were assessed using flow cytometry: CD4+ and CD8+ T cells (Naïve, NA; Central memory, CM; and Effector cells, EM and EMRA; using CD27/CD45RA), Stem cell-like memory T cells (TSCMs; using CD95/CD127), B cells (plasmablasts, memory, immature and naïve cells using CD19/CD27/CD38/CD10) and Natural Killer cells (effector and regulatory cells, using CD56/CD16). T cell function was assessed by unstimulated HLA-DR expression or interferon gamma (IFN-γ) production with Enzyme-linked ImmunoSpot assays following stimulation with virus or tumour-associated antigens.

Results

Total leukocyte counts, lymphocytes, monocytes and neutrophils did not change with training (p > 0.425). Most CD4+ and CD8+ T cell subtypes, including TSCMs, and B cell and NK cell subtypes did not change (p > 0.127). However, across groups combined, the CD4+ EMRA T cell count was lower after training (cells/µl: 18 ± 33 vs. 12 ± 22, p = 0.028) and these cells were less activated on a per cell basis (HLA-DR median fluorescence intensity: 463 ± 138 vs. 420 ± 77, p = 0.018). Furthermore, the partly-supervised group showed a significant decrease in the CD4+/CD8+ ratio (3.90 ± 2.98 vs. 2.54 ± 1.29, p = 0.006) and a significant increase of regulatory NK cells (cells/µl: 16 ± 8 vs. 21 ± 10, p = 0.011). T cell IFN-γ production did not change with exercise training (p > 0.515).

Discussion

In summary, most immune cell characteristics are relatively stable with 8 weeks of exercise training among breast cancer survivors. The lower counts and activation of CD4+ EMRA T cells, might reflect an anti-immunosenescence effect of exercise.

Inflammatory markers in patients with hypertension

Hypertension is a chronic disease with high levels of morbidity and disability. Elevated blood pressure can lead to many complications and is the main risk factor for stroke, heart failure and nephropathy. Factors associated with hypertension and inflammatory response differ from those associated with vascular inflammation. The immune system plays a vital role in the pathophysiology of hypertension. Inflammation is particularly relevant in the progression of cardiovascular diseases, which has led to extensive research on inflammatory markers and indicators.

The influence of physical activity level and cytomegalovirus serostatus on the cytokine levels of young individuals

The practice of physical activity (PA) is a non-pharmacological variable that alters the immune response through changes in cytokines and cellular immunity. Inversely latent cytomegalovirus (CMV) infection prematurely ages the immune system and contributes to the chronic inflammatory condition in several diseases and in aging. This study aimed to compare the association of the PA level and CMV serostatus on whole blood mitogen-stimulated cytokine production of young individuals. The resting blood samples were collected from 100 volunteers of both sexes assigned to one of six groups according to the degree of PA and CMV serostatus: sedentary CMV- (n = 15), moderate physical activity CMV- (moderate PA CMV -, n = 15), high physical activity CMV- (high PA CMV-, n = 15), sedentary CMV+ (n = 20), moderate physical activity CMV + (moderate PA CMV+, n = 20) and high physical activity CMV + (high PA CMV +, n = 20). The collected peripheral blood got diluted in supplemented RPMI-1640 culture medium and incubated for 48 hours with a 2% concentration of phytohemagglutinin at 37ºC and CO2 at 5%. The supernatants were collected and used for the IL-6, IL-10, TNF-α, and INF-γ analysis by the ELISA method. The IL-10 concentration was higher in the Moderate PA and High PA groups when compared to the sedentary group, regardless of CMV status. The physically active (moderate and high PA) CMV+ individuals presented lower concentrations of IL-6 and TNF-α compared to CMV+ sedentary individuals, and the sedentary CMV+ subjects had a higher concentration of INF-γ compared to Sedentary CMV- subjects (p < 0.05). In summary, it is possible to infer that PA is key to controlling inflammation related to CMV infection. The stimulation of physical exercise is an important factor in controlling many diseases at the populational level.

Age-related changes in peripheral T-cell subpopulations in elderly individuals: An observational study

The age-related decline in T-cell function among elderly individuals remains unclear. We thus investigated the interrelationship between T-cell subsets and age to identify the changes in T-cell phenotypes and develop an age prediction model for the elderly population. A total of 127 individuals aged >60 years were divided into three groups (youngest-old group, 61-70 years, n = 34; middle-old group, 71-80 years, n = 53; and oldest-old group, ≥ 81 years, n = 40). The percentage of CD8+CD28- cells (P = 0.001) was highest in the oldest-old group and then followed by the middle-old group, while the youngest-old group was the lowest. Both females and males demonstrated significant decreases in the absolute counts of CD4+CD45RA+ cells (P = 0.020; P = 0.002) and CD8+CD28+ cells (P = 0.015; P = 0.005) with age. Multivariate linear regression showed that the percentage of CD8+CD28- cells (P < 0.001) was an independent predictor of aging after adjusting for sex, body mass index, hospitalization duration, smoking, drinking, chronic medical illness, and medications at admission. In conclusion, our results suggest that aging in elderly individuals is accompanied by a decrease in the counts of T-cell subpopulations. CD8+CD28- cells may be potential targets for elderly individuals in antiaging-related immunosenescence.

The Impact of Exercise on Immunity, Metabolism, and Atherosclerosis

Physical exercise represents an effective preventive and therapeutic strategy beneficially modifying the course of multiple diseases. The protective mechanisms of exercise are manifold; primarily, they are elicited by alterations in metabolic and inflammatory pathways. Exercise intensity and duration strongly influence the provoked response. This narrative review aims to provide comprehensive up-to-date insights into the beneficial effects of physical exercise by illustrating the impact of moderate and vigorous exercise on innate and adaptive immunity. Specifically, we describe qualitative and quantitative changes in different leukocyte subsets while distinguishing between acute and chronic exercise effects. Further, we elaborate on how exercise modifies the progression of atherosclerosis, the leading cause of death worldwide, representing a prime example of a disease triggered by metabolic and inflammatory pathways. Here, we describe how exercise counteracts causal contributors and thereby improves outcomes. In addition, we identify gaps that still need to be addressed in the future.

Associations of lifestyle with physical, hearing, visual, and mental functional impairments among older adults: Findings from two prospective cohort studies

OBJECTIVE

To examine the associations between lifestyle habits and functional impairments among older adults.

METHODS

The study includes 20,545 women and 14,374 men aged 70 years or older at the time of the function assessment. Participants were from two prospective cohort studies: the Shanghai Women's Health Study (SWHS, enrollment from 1996 to 2000) and the Shanghai Men's Health Study (SMHS, enrollment from 2002 to 2006). Lifestyle information was collected at study enrollment and a healthy lifestyle score (HLS) was derived. Functional impairment information was collected at the follow-up survey conducted in 2012-2017. Logistic regression analyses were applied to estimate the associations of HLS with functional impairments.

RESULTS

The average age at lifestyle and functional impairment assessment was 62.3 (range: 49.9-70.9) and 77.7 (range: 70.0-89.4) for women and 67.5 (range: 55.1-74.9) and 77.4 (range: 70.0-88.6) for men. After a median follow-up of 14.4 years, we found that the HLS was inversely associated with overall severe functional impairment: odds ratio (95% confidence interval), 0.78(0.71-0.86) and individual severe functional impairment: 0.67(0.62-0.73) for independent walking, 0.85(0.77-0.94) for hearing/vision, 0.79(0.70-0.88) for memory, and 0.74(0.67-0.82) for decision-making impairment, comparing the highest with the lowest HLS categories. Such associations were similar among individuals with/without cardiometabolic diseases at baseline. The associations between each lifestyle factor and functional impairments differed.

CONCLUSION

A healthy lifestyle was associated with reduced odds of physical and mental impairment among older Chinese adults, emphasizing the importance of promoting and maintaining a healthy lifestyle to prevent or postpone age-related functional impairments.

Assessment of metabolic syndrome predictors in relation to inflammation and visceral fat tissue in older adults

The diagnosis of metabolic syndrome (MetS) focuses on the assessment of risk factors such as insulin resistance, dyslipidemia, central adiposity and elevated blood pressure. Evidence suggests that markers of systemic inflammation may also be included in the definition of MetS and play some role in its pathogenesis. The study was designed to evaluate low-grade inflammation status in older adults with MetS in relation to increased body fat tissue and an attempt was made to evaluate new predictors for MetS through the analysis of the ROC Curve. Ninety-six middle-aged (69.2 ± 4.9) individuals from University of Third Age (women n = 75 and men n = 21) were allocated to two groups: without metabolic syndrome (n = 37) and with metabolic syndrome (n = 59) according to International Diabetes Federation criteria in agreement with American Heart Association/National Heart, Lung and Blood Institute 2009. Participants' current health status was assessed using medical records from a routine follow-up visit to a primary care physician. Statistical analysis was performed using R studio software. Depending on the normal distribution, ANOVA or the Kruskal-Wallis test was used. The optimal threshold value for clinical stratification (cut-off value) was obtained by calculating the Youden index. The AUC was observed to be the highest for a new anthropometric index i.e. lipid accumulation product (0.820). Low-grade inflammation dominated in MetS group (BMI 28.0 ± 4.4 kg/m², WHR 0.9 ± 0.1, FM 24.7 ± 7.9 kg) where significantly higher values of TNF-α (p = 0.027) and HGMB-1 protein (p = 0.011) were recorded.The optimal threshold values for immunological indices assessed as new predictors of the metabolic syndrome were: 93.4 for TNF-α, 88.2 for HGMB-1 protein and 1992.75 for ghrelin. High AUC values for these indices additionally confirmed their high diagnostic usefulness in MetS.

Activity-Dependent Induction of Younger Biological Phenotypes

In several mammalian species, including humans, complex stimulation patterns such as cognitive and physical exercise lead to improvements in organ function, organism health and performance, as well as possibly longer lifespans. A framework is introduced here in which activity-dependent transcriptional programs, induced by these environmental stimuli, move somatic cells such as neurons and muscle cells toward a state that resembles younger cells to allow remodeling and adaptation of the organism. This cellular adaptation program targets several process classes that are heavily implicated in aging, such as mitochondrial metabolism, cell-cell communication, and epigenetic information processing, and leads to functional improvements in these areas. The activity-dependent gene program (ADGP) can be seen as a natural, endogenous cellular reprogramming mechanism that provides deep insight into the principles of inducible improvements in cell and organism function and can guide the development of therapeutic approaches for longevity. Here, these ADGPs are analyzed, exemplary critical molecular nexus points such as cAMP response element-binding protein, myocyte enhancer factor 2, serum response factor, and c-Fos are identified, and it is explored how one may leverage them to prevent, attenuate, and reverse human aging-related decline of body function.

Immunosenescence in Aging-Related Vascular Dysfunction

The immunosenescence-related disproportion in T lymphocytes may have important consequences for endothelial dysfunction, which is a key event in vascular aging. The study was designed to assess the prognostic values of the inflammatory-immune profile to better predict and prevent vascular diseases associated with old age. Eighty individuals aged 70.9 ± 5.3 years were allocated to a low- (LGI) or high-grade inflammation (HGI) group based on CRP (<3 or ≥3 mg/L) as a conventional risk marker of cardiovascular diseases. Significant changes in inflammatory and endothelium-specific variables IL-1β, IL-6, TNFα, oxLDL, H2O2, NO, 3-nitrotyrosine, and endothelial progenitor cells (OR 7.61, 95% CI 2.56−29.05, p < 0.0001), confirmed their interplay in vascular inflammation. The flow-cytometry analysis demonstrated a high disproportion in T lymphocytes CD4+ and CD8+ between LGI and HGI groups. CRP was <3 mg/mL for the CD4/CD8 ratio within the reference values ≥ 1 or ≤2.5, unlike for the CD4/CD8 ratio < 1 and >2.5. The odds ratios for the distribution of CD4+ (OR 5.98, 95% CI 0.001−0.008, p < 0.001), CD8+ (OR 0.23, 95% CI 0.08−0.59, p < 0.01), and CD8CD45RO+ T naïve cells (OR 0.27, 95% CI 0.097−0.695, p < 0.01) and CD4/CD8 (OR 5.69, 95% CI 2.07−17.32, p < 0.001) indicated a potential diagnostic value of T lymphocytes for clinical prognosis in aging-related vascular dysfunction.

Cellular senescence: the good, the bad and the unknown

Cellular senescence is a ubiquitous process with roles in tissue remodelling, including wound repair and embryogenesis. However, prolonged senescence can be maladaptive, leading to cancer development and age-related diseases. Cellular senescence involves cell-cycle arrest and the release of inflammatory cytokines with autocrine, paracrine and endocrine activities. Senescent cells also exhibit morphological alterations, including flattened cell bodies, vacuolization and granularity in the cytoplasm and abnormal organelles. Several biomarkers of cellular senescence have been identified, including SA-βgal, p16 and p21; however, few markers have high sensitivity and specificity. In addition to driving ageing, senescence of immune and parenchymal cells contributes to the development of a variety of diseases and metabolic disorders. In the kidney, senescence might have beneficial roles during development and recovery from injury, but can also contribute to the progression of acute kidney injury and chronic kidney disease. Therapies that target senescence, including senolytic and senomorphic drugs, stem cell therapies and other interventions, have been shown to extend lifespan and reduce tissue injury in various animal models. Early clinical trials confirm that senotherapeutic approaches could be beneficial in human disease. However, larger clinical trials are needed to translate these approaches to patient care.

Age-Related Adaptive Immune Changes in Parkinson’s Disease

Ageing is a major risk factor for most neurodegenerative diseases, including Parkinson’s disease (PD). Progressive age-related dysregulation of the immune system is termed immunosenescence and is responsible for the weakened response to novel antigens, increased susceptibility to infections and reduced effectiveness of vaccines seen in the elderly. Immune activation, both within the brain and periphery, is heavily implicated in PD but the role of immunosenescence has not been fully explored. Studies to date provide some evidence for an attenuation in immunosenescence in PD, particularly a reduction in senescent CD8 T lymphocytes in PD cases compared to similarly aged controls. Here, we discuss recent evidence of age-related immune abnormalities in PD with a focus on T cell senescence and explore their potential role in disease pathogenesis and development.

Systemic Inflammatory Predictors of In-Hospital Mortality in COVID-19 Patients: A Retrospective Study

The purpose of this study was to investigate whether routine blood tests and clinical characteristics can predict in-hospital mortality in COVID-19. Clinical data of 285 patients aged 59.7 ± 10.3 yrs. (males n = 189, females n = 96) were retrospectively collected from December 2020 to June 2021. Routine blood tests were recorded within the 1st hour of admission to hospital. The inflammatory variables, such as C-reactive protein (CRP), procalcitonin (PCT), neutrophils−lymphocyte ratio (NLR) and the systemic inflammatory index (SII), exceeded the reference values in all patients and were significantly higher in deceased patients (n = 108) compared to survivors (n = 177). The log-rank test for comparing two survival curves showed that patients aged ≥60.5 years, with PCT ≥ 0.188 ng/mL or NLR ≥ 11.57 103/µL were at a greater risk of death. NLR demonstrated a high impact on the COVID-19 mortality (HR 1.317; 95%CI 1.004−1.728; p < 0.05), whereas CRP and SII showed no effect (HR 1.000; 95%CI 1.000−1.004; p = 0.085 and HR 1.078; 95%CI 0.865−1.344; p = 0.503, respectively). In the first Polish study including COVID-19 patients, we demonstrated that age in relation to simple parameters derived from complete blood cell count has prognostic implications in the course of COVID-19 and can identify the patients at a higher risk of in-hospital mortality.

Concurrent Training Increases Serum Brain-Derived Neurotrophic Factor in Older Adults Regardless of the Exercise Frequency

Background

Human brain function declines with aging. In this sense, exercise-based interventions has a promising effect on brain plasticity for older adults. Serum brain-derived neurotrophic factor (BDNF) is a positive biomarker for brain neuroplasticity in healthy older adults also modified by exercise training. Selected features of the exercise prescription for improving brain health are missing; therefore, the aim of this study was to determine the effects of concurrent exercise training frequency on serum BDNF levels in healthy older adults.

Methods

Nineteen volunteers (age: 65 ± 4 year; body mass index: 28.0 ± 4.5 kg/m²) completed either a three times/week (3-t/w) (n = 8) or five times/week (5-t/w) (n = 11) concurrent exercise program. The exercise program lasted 11 weeks and all exercise sessions were performed for 50 min at moderate intensity. Serum BDNF, body composition, cardiovascular, and physical fitness variables were assessed before and after the exercise training program.

Results

Regardless of the group, the serum BDNF increased following the intervention (p < 0.001), and there were no significant group (p = 0.827) or interaction (p = 0.063) effects. The maximal oxygen consumption (VO2max) increased regardless of the group (p = 0.007), with a non-significant group (p = 0.722) or interaction (p = 0.223) effects. Upper- and lower-body strength increased in both groups (p = 0.003); however, there was no effect of the training frequency (p = 0.53). For the skeletal muscle mass, there was a trend in the interaction effect (p = 0.053). Finally, the body fat percentage was unchanged.

Conclusion

Eleven weeks of combined exercise training increased serum BDNF levels in healthy older adults, a response independent of the training frequency. The overall fitness level improved similarly in both exercise groups. These data reveal that a minimal dosage of concurrent exercise enhance functional capacity and a brain health biomarker in older adults.

Pre-Existing Hypertension Is Related with Disproportions in T-Lymphocytes in Older Age

Age-related immune deficiencies increase the risk of comorbidities and mortality. This study evaluated immunosenescence patterns by flow cytometry of naïve and memory T cell subpopulations and the immune risk profile (IRP), expressed as the CD4/CD8 ratio and IgG CMV related to comorbidities. The disproportions in naïve and memory T cells, as well as in the CD4/CD8 ratio, were analysed in 99 elderly individuals (71.9 ± 5.8 years) diagnosed with hypertension (n = 51) or without hypertension (n = 48), using an eight-parameter flow cytometer. The percentage of CD4+ T lymphocytes was significantly higher in hypertensive than other individuals independently from CMV infections, with approximately 34% having CD4/CD8 > 2.5, and only 4% of the elderly with hypertension having CD4/CD8 < 1. The elderly with a normal BMI demonstrated the CD4/CD8 ratio ≥ 1 or ≤ 2.5, while overweight and obese participants showed a tendency to an inverted CD4/CD8 ratio. CD4/CD8 ratio increased gradually with age and reached the highest values in participants aged >75 years. The decline in CD4+ naïve T lymphocytes was more prominent in IgG CMV+ men when compared to IgG CMV+ women. The changes in naïve and memory T lymphocyte population, CD4/CD8, and CMV seropositivity included in IRP are important markers of health status in the elderly that are dependent on hypertension.

Exercise as a Peripheral Circadian Clock Resynchronizer in Vascular and Skeletal Muscle Aging

Aging is characterized by several progressive physiological changes, including changes in the circadian rhythm. Circadian rhythms influence behavior, physiology, and metabolic processes in order to maintain homeostasis; they also influence the function of endothelial cells, smooth muscle cells, and immune cells in the vessel wall. A clock misalignment could favor vascular damage and indirectly also affect skeletal muscle function. In this review, we focus on the dysregulation of circadian rhythm due to aging and its relationship with skeletal muscle changes and vascular health as possible risk factors for the development of sarcopenia, as well as the role of physical exercise as a potential modulator of these processes.

Physical Activity and Nutritional Influence on Immune Function: An Important Strategy to Improve Immunity and Health Status

Physical activity (PA) and nutrition are the essential components of a healthy lifestyle, as they can influence energy balance, promote functional ability of various systems and improve immunity. Infections and their associated symptoms are the common and frequent challenges to human health that are causing severe economic and social consequences around the world. During aging, human immune system undergoes dramatic aging-related changes/dysfunctions known as immunosenescence. Clinically, immunosenescence refers to the gradual deterioration of immune system that increases exposure to infections, and reduces vaccine efficacy. Such phenomenon is linked to impaired immune responses that lead to dysfunction of multiple organs, while lack of physical activity, progressive loss of muscle mass, and concomitant decline in muscle strength facilitate immunosenescence and inflammation. In the present review, we have discussed the role of nutrition and PA, which can boost the immune system alone and synergistically. Evidence suggests that long-term PA is beneficial in improving immune system and preventing various infections. We have further discussed several nutritional strategies for improving the immune system. Unfortunately, the available evidence shows conflicting results. In terms of interaction with food intake, PA does not tend to increase energy intake during a short time course. However, overcoming nutritional deficiencies appears to be the most practical recommendation. Through the balanced nutritious diet intake one can fulfill the bodily requirement of optimal nutrition that significantly impacts the immune system. Supplementation of a single nutrient as food is generally not advisable. Rather incorporating various fruits and vegetables, whole grains, proteins and probiotics may ensure adequate nutrient intake. Therefore, multi-nutrient supplements may benefit people having deficiency in spite of sufficient diet. Along with PA, supplementation of probiotics, bovine colostrum, plant-derived products and functional foods may provide additional benefits in improving the immune system.

The Association of Anti-Inflammatory Diet Ingredients and Lifestyle Exercise with Inflammaging

One of the latest theories on ageing focuses on immune response, and considers the activation of subclinical and chronic inflammation. The study was designed to explain whether anti-inflammatory diet and lifestyle exercise affect an inflammatory profile in the Polish elderly population. Sixty individuals (80.2 ± 7.9 years) were allocated to a low-grade inflammation (LGI n = 33) or high-grade inflammation (HGI n = 27) group, based on C-reactive protein concentration (<3 or ≥3 mg/L) as a conventional marker of systemic inflammation. Diet analysis focused on vitamins D, C, E, A, β-carotene, n-3 and n-6 PUFA using single 24-h dietary recall. LGI demonstrated a lower n-6/n-3 PUFA but higher vitamin D intake than HGI. Physical performance based on 6-min walk test (6MWT) classified the elderly as physically inactive, whereby LGI demonstrated a significantly higher gait speed (1.09 ± 0.26 m/s) than HGI (0.72 ± 0.28 m/s). Circulating interleukins IL-1β, IL-6, IL-13, TNFα and cfDNA demonstrated high concentrations in the elderly with low 6MWT, confirming an impairment of physical performance by persistent systemic inflammation. These findings reveal that increased intake of anti-inflammatory diet ingredients and physical activity sustained throughout life attenuate progression of inflammaging in the elderly and indicate potential therapeutic strategies to counteract pathophysiological effects of ageing.