Inflammatory and immune markers associated with physical frailty syndrome: findings from Singapore longitudinal aging studies

Senolytics improve physical function and increase lifespan in old age

Physical function declines in old age, portending disability, increased health expenditures, and mortality. Cellular senescence, leading to tissue dysfunction, may contribute to these consequences of aging, but whether senescence can directly drive age-related pathology and be therapeutically targeted is still unclear. Here we demonstrate that transplanting relatively small numbers of senescent cells into young mice is sufficient to cause persistent physical dysfunction, as well as to spread cellular senescence to host tissues. Transplanting even fewer senescent cells had the same effect in older recipients and was accompanied by reduced survival, indicating the potency of senescent cells in shortening health- and lifespan. The senolytic cocktail, dasatinib plus quercetin, which causes selective elimination of senescent cells, decreased the number of naturally occurring senescent cells and their secretion of frailty-related proinflammatory cytokines in explants of human adipose tissue. Moreover, intermittent oral administration of senolytics to both senescent cell-transplanted young mice and naturally aged mice alleviated physical dysfunction and increased post-treatment survival by 36% while reducing mortality hazard to 65%. Our study provides proof-of-concept evidence that senescent cells can cause physical dysfunction and decreased survival even in young mice, while senolytics can enhance remaining health- and lifespan in old mice.

Síndrome da fragilidade e fatores associados em idosos residentes em instituições de longa permanência

RESUMO Estudo descritivo em instituições de longa permanência para investigar a prevalência de fragilidade e de fatores associados em idosos institucionalizados e sua associação com variáveis sociodemográficas e condições de saúde. Foram investigados 214 idosos, a maioria do sexo feminino (69,6%), estado civil solteiro (53,7%), escolaridade de um ano (54,4%) e renda de até um salário mínimo (73,4%). Quanto à cognição, 79,4% foram reprovados por erros significativos. A síndrome de fragilidade foi identificada em 70,1% dos idosos. Todos os fatores incluídos na escala de fragilidade alcançaram significância estatística. Na análise multivariada, os fatores que mais contribuem para a fragilidade são: cognição, independência funcional, autoavaliação de saúde, frequência de suporte social, percepção de perda de peso e depressão.

Combined Inflammation and Metabolism Biomarker Indices of Robust and Impaired Physical Function in Older Adults

OBJECTIVES

To determine whether combinations of inflammatory markers are related to physical function.

DESIGN AND SUBJECTS

secondary analysis of baseline of three observational studies of community-dwelling older adults MEASUREMENTS: The baseline data from 3 cohorts of older adults with different health and disease status were employed. Twenty markers of inflammation and metabolism were individually assessed for correlation with usual gait speed and were separated into robust and impairment quartiles. For the robustness and impairment indices, individual markers were selected using step-wise regression over bootstrapping iterations, and regression coefficients were estimated for the markers individually and collectively as an additive score.

RESULTS

We developed a robustness index involving 6 markers and an impairment index involving 8 markers corresponding positively and negatively with gait speed. Two markers, glycine and tumor necrosis factor receptor 1 (TNFR1), appeared only in the robustness index, and TNFR2; regulated on activation, normal T-cell expressed and secreted; the amino acid factor; and matrix metallopeptidase 3; appeared only in the impairment index.

CONCLUSION

Indices of biomarkers were associated with robust and impaired physical performance but differ, in composition suggesting potential biological differences that may contribute to robustness and impairment.

The Asia-Pacific Clinical Practice Guidelines for the Management of Frailty

OBJECTIVE

To develop Clinical Practice Guidelines for the screening, assessment and management of the geriatric condition of frailty.

METHODS

An adapted Grading of Recommendations, Assessment, Development, and Evaluation approach was used to develop the guidelines. This process involved detailed evaluation of the current scientific evidence paired with expert panel interpretation. Three categories of Clinical Practice Guidelines recommendations were developed: strong, conditional, and no recommendation.

RECOMMENDATIONS

Strong recommendations were (1) use a validated measurement tool to identify frailty; (2) prescribe physical activity with a resistance training component; and (3) address polypharmacy by reducing or deprescribing any inappropriate/superfluous medications. Conditional recommendations were (1) screen for, and address modifiable causes of fatigue; (2) for persons exhibiting unintentional weight loss, screen for reversible causes and consider food fortification and protein/caloric supplementation; and (3) prescribe vitamin D for individuals deficient in vitamin D. No recommendation was given regarding the provision of a patient support and education plan.

CONCLUSIONS

The recommendations provided herein are intended for use by healthcare providers in their management of older adults with frailty in the Asia Pacific region. It is proposed that regional guideline support committees be formed to help provide regular updates to these evidence-based guidelines.

Circulating levels of monocyte chemoattractant protein-1 as a potential measure of biological age in mice and frailty in humans

A serum biomarker of biological versus chronological age would have significant impact on clinical care. It could be used to identify individuals at risk of early-onset frailty or the multimorbidities associated with old age. It may also serve as a surrogate endpoint in clinical trials targeting mechanisms of aging. Here, we identified MCP-1/CCL2, a chemokine responsible for recruiting monocytes, as a potential biomarker of biological age. Circulating monocyte chemoattractant protein-1 (MCP-1) levels increased in an age-dependent manner in wild-type (WT) mice. That age-dependent increase was accelerated in Ercc1-/Δ and Bubr1H/H mouse models of progeria. Genetic and pharmacologic interventions that slow aging of Ercc1-/Δ and WT mice lowered serum MCP-1 levels significantly. Finally, in elderly humans with aortic stenosis, MCP-1 levels were significantly higher in frail individuals compared to nonfrail. These data support the conclusion that MCP-1 can be used as a measure of mammalian biological age that is responsive to interventions that extend healthy aging.

The pro-inflammatory phenotype of the human non-classical monocyte subset is attributed to senescence

Human primary monocytes comprise a heterogeneous population that can be classified into three subsets based on CD14 and CD16 expression: classical (CD14^high/CD16⁻), intermediate (CD14^high/CD16⁺), and non-classical (CD14^low/CD16⁺). The non-classical monocytes are the most pro-inflammatory in response to TLR stimulation in vitro, yet they express a remarkably high basal level of miR-146a, a microRNA known to negatively regulate the TLR pathway. This concurrence of a pro-inflammatory status and a high miR-146a level has been associated with cellular senescence in other cell types. Hence, we assessed the three monocyte subsets for evidence of senescence, including proliferative status, telomere length, cellular ROS levels, and mitochondrial membrane potential. Indeed, the non-classical subset exhibited the clearest hallmarks of senescence, followed by the intermediate and then the classical subset. In addition, the non-classical subset secreted pro-inflammatory cytokines basally in vitro. The highly pro-inflammatory nature of the non-classical monocytes could be a manifestation of the senescence-associated secretory phenotype (SASP), likely induced by a high basal NF-κB activity and IL-1α production. Finally, we observed an accumulation of the non-classical monocytes, in conjunction with higher levels of plasma TNF-α and IL-8, in the elderly. These factors may contribute to inflamm-aging and age-related inflammatory conditions, such as atherosclerosis and osteoarthritis. With our new understanding that the non-classical monocyte subset is a senescent population, we can now re-examine the role of this subset in disease conditions where this subset expands.

Vitamin B12 deficiency and impaired expression of amnionless during aging

BACKGROUND

Physical frailty and loss of mobility in elderly individuals lead to reduced independence, quality of life, and increased mortality. Vitamin B12 deficiency has been linked to several age-related chronic diseases, including in the musculo-skeletal system, where vitamin B12 deficiency is generally believed to be linked to poor nutritional intake. In the present study, we asked whether aging and frailty associate with altered vitamin B12 homeostasis in humans and investigated the underlying molecular mechanisms using preclinical models.

METHODS

We analysed a subset of the Singapore Longitudinal Aging Study and stratified 238 participants based on age and Fried frailty criteria. Levels of methyl-malonic acid (MMA), a marker for vitamin B12 deficiency, and amnionless, the vitamin B12 co-receptor that anchors the vitamin B12 transport complex to the membrane of epithelial cells, were measured in plasma. In addition, vitamin B12 levels and the molecular mechanisms of vitamin B12 uptake and excretion were analysed in ileum, kidney, liver, and blood using a rat model of natural aging where nutritional intake is fully controlled.

RESULTS

We demonstrate that aging and frailty are associated with a higher prevalence of functional vitamin B12 deficiency that can be detected by increased levels of MMA in blood (ρ = 0.25; P = 0.00013). The decline in circulating vitamin B12 levels is recapitulated in a rat model of natural aging where food composition and intake are stable. At the molecular level, these perturbations involve altered expression of amnionless in the ileum and kidney. Interestingly, we demonstrate that amnionless can be detected in serum where its levels increase during aging in both rodents and human (P = 3.3e-07 and 9.2e-07, respectively). Blood amnionless levels negatively correlate with vitamin B12 in rats (r²  = 0.305; P = 0.0042) and positively correlate with the vitamin B12 deficiency marker MMA in humans (ρ = 0.22; P = 0.00068).

CONCLUSIONS

Our results demonstrate that aging and frailty cause intrinsic vitamin B12 deficiencies, which can occur independently of nutritional intake. Mechanistically, vitamin B12 deficiency involves the physio-pathological decline of both the intestinal uptake and the renal reabsorption system for vitamin B12. Finally, amnionless is a novel biomarker which can detect perturbed vitamin B12 bioavailability during aging and physical frailty.

High-Throughput Screening of Senescence Markers in Hematopoietic Stem Cells Derived from Induced Pluripotent Stem Cells

The successful development and characterization of human induced pluripotent stem cells (iPSCs) provides a powerful tool to study the molecular mechanisms that control cell fate decisions and differentiation toward distinct lineages. Here we focus on the ability of donors derived iPSCs to differentiate toward hematopoietic progenitor cells and on the analysis of their telomere length. The ability to screen telomere length in individual donors is important for defining cellular senescence, which correlates with their differentiation potential toward hematopoietic lineages. We have modified iPSC culture protocol and telomere length analysis to suit for high throughput screening of telomere length in large number of individual donors. This approach can be used to demonstrate the heterogeneity or changes of telomere length and its shortening as an exclusion criterion for selection of suitable donors for future stem cell therapies.

Fighting against a protean enemy: immunosenescence, vaccines, and healthy aging

The progressive increase of the aged population worldwide mandates new strategies to ensure sustained health and well-being with age. The development of better and/or new vaccines against pathogens that affect older adults is one pivotal intervention in approaching this goal. However, the functional decline of various physiological systems, including the immune system, requires novel approaches to counteract immunosenescence. Although important progress has been made in understanding the mechanisms underlying the age-related decline of the immune response to infections and vaccinations, knowledge gaps remain, both in the areas of basic and translational research. In particular, it will be important to better understand how environmental factors, such as diet, physical activity, co-morbidities, and pharmacological treatments, delay or contribute to the decline of the capability of the aging immune system to appropriately respond to infectious diseases and vaccination. Recent findings suggest that successful approaches specifically targeted to the older population can be developed, such as the high-dose and adjuvanted vaccines against seasonal influenza, the adjuvanted subunit vaccine against herpes zoster, as well as experimental interventions with immune-potentiators or immunostimulants. Learning from these first successes may pave the way to developing novel and improved vaccines for the older adults and immunocompromised. With an integrated, holistic vaccination strategy, society will offer the opportunity for an improved quality of life to the segment of the population that is going to increase most significantly in numbers and proportion over future decades.

Assessing inflammageing

PURPOSE OF REVIEW

Immunosenescence has been scrutinized in detail, and evidence that inflammation and ageing are interrelated is consistent. Still, a gold standard for assessing the biological age of the immune function in an individual patient is lacking, so that immunosenescence is still not a quantifiable criterion in clinical decision-making processes.

RECENT FINDINGS

This review highlights recent (partly ongoing) studies into biomarkers of inflammation to assess immunosenescence, including large-scale studies, and quotes expert opinion statements. Markers of basal inflammation frequently used include interleukin-6, tumor necrosis factor-α and receptors p55 and p75, C-reactive protein and cytomegalovirus antibody levels. Some cellular markers are particularly advocated to reflect age-related decay of specific immunity, namely the decrease of naive T cells, especially CD8cells, and accumulations of memory T cells, especially late-stage differentiated CD8 cells; the loss of CD28 on lymphocytes is also taken as a biomarker of immunosenescence.

SUMMARY

Substantial progress has been made in both understanding and phenotyping immunosenescence and inflammageing. The diagnosis of the degree of immunosenescence in the individual patient, however, has not yet been standardized.

Association of pre-chemotherapy peripheral blood pro-inflammatory and coagulation factors with reduced relative dose intensity in women with breast cancer

Background

Chemotherapy decreases the risk of relapse and mortality in early-stage breast cancer (BC), but it comes with the risk of toxicity. Chemotherapy efficacy depends on relative dose intensity (RDI), and an RDI < 85% is associated with worse overall survival. The pro-inflammatory (interleukin (IL)-6, C-reactive protein (CRP)) and coagulation factors (D-dimer) serve as biomarkers of aging. The purpose of this study is to determine if these biomarkers are associated with reduced RDI in women with stage I–III BC.

Methods

This study enrolled women with stage I–III BC. Prior to adjuvant or neoadjuvant chemotherapy, peripheral blood was collected for biomarker measurement. Dose reductions and delays were captured and utilized to calculate the RDI delivered. Univariate and multivariate analyses were performed to describe the association between pre-chemotherapy IL-6, CRP, and D-dimer levels and an RDI < 85%, controlling for relevant tumor and patient factors (age, stage, receptor status, chemotherapy regimen, and pre-chemotherapy physical function and comorbidity).

Results

A total of 159 patients (mean age 58 years, range 30–81, SD 11.3) with stage I–III BC were enrolled. An RDI < 85% occurred in 22.6% (N = 36) of patients and was associated with higher pre-chemotherapy IL-6 (OR 1.14, 95% CI 1.04–1.25; p = 0.006) and D-dimer (OR 2.32, 95% CI 1.27–4.24; p = 0.006) levels, increased age (p = 0.001), increased number of comorbidities (p = 0.01), and decreased physical function by the Medical Outcomes Survey Activities of Daily Living (ADL) Scale (p = 0.009) in univariate analysis. A multivariate model, including two biomarkers (IL-6 and D-dimer), age, ADL, BC stage, and chemotherapy regimen, demonstrated a significant association between the increased biomarkers and reduced RDI < 85% (OR 2.54; p = 0.04).

Conclusions

Increased pre-chemotherapy biomarkers of aging (IL-6 and D-dimer) are associated with reduced RDI (<85%). Future studies are underway to validate these findings.

Trial registration

ClinicalTrials.gov, NCT01030250. Registered on 3 November 2016.

Electronic supplementary material

The online version of this article (doi:10.1186/s13058-017-0895-5) contains supplementary material, which is available to authorized users.

Frailty Syndrome and Risk of Sepsis in the REasons for Geographic And Racial Differences in Stroke (REGARDS) Cohort

BACKGROUND:

Frailty is associated with increased morbidity and mortality in older persons. We sought to characterize the associations between the frailty syndrome and long-term risk of sepsis in a large cohort of community-dwelling adults.

METHODS:

We analyzed data on 30 239 community-dwelling adult participants in the REasons for Geographic and Racial Differences in Stroke (REGARDS) cohort. We defined frailty as the presence of at least 2 frailty indicators (weakness, exhaustion, and low physical activity). We defined sepsis as hospitalization for a serious infection with ≥2 system inflammatory response syndrome criteria, identified for the period 2003-2012. We determined the associations between frailty and risk of first sepsis and sepsis 30-day case fatality.

RESULTS:

Among REGARDS participants, frailty was present in 6018 (19.9%). Over the 10-year observation period, there were 1529 first-sepsis hospitalizations. Frailty was associated with increased risk of sepsis (adjusted hazard ratio [HR] 1.44; 95% CI: 1.26 to 1.64). The total number of frailty indicators was associated with increased risk of sepsis ( P trend <.001). Among first-sepsis hospitalizations, frailty was associated with increased sepsis 30-day case fatality (adjusted OR 1.62; 95% CI: 1.06 to 2.50).

CONCLUSIONS:

In the REGARDS cohort, frailty was associated with increased long-term risk of sepsis and sepsis 30-day case fatality.