Frailty in Aging and the Search for the Optimal Biomarker: A Review

Explainable machine learning framework for biomarker discovery by combining biological age and frailty prediction

Biological age (BA) and frailty represent two distinct health measures that offer valuable insights into the aging process. Comparing and analyzing blood-based biomarkers from the machine learning (ML) predictors of BA and frailty helps deepen our understanding of aging. This study aimed to develop a novel framework to identify biomarkers of aging by combining BA and frailty ML predictors with eXplainable Artificial Intelligence (XAI) techniques. We utilized data from middle-aged and older Chinese adults (≥ 45 years) in the 2011/2012 wave (n = 9702) and the 2015/2016 wave (n = 9455, as test set validation) of the China Health and Retirement Longitudinal Study (CHARLS). Sixteen blood-based biomarkers were used to predict BA and frailty. Four tree-based ML algorithms were employed in the training and validation, and performance metrics were compared to select the best models. Then, SHapley Additive exPlanations (SHAP) analysis was conducted on the selected models. CatBoost performed the best in the BA predictor, and Gradient Boosting performed the best in the frailty predictor. Traditional ML feature importance identified cystatin C and glycated hemoglobin as the major contributors for their respective models. However, subsequent SHAP analysis demonstrated that only cystatin C was the primary contributor in both models. The proposed framework can easily incorporate additional biomarkers, providing a scalable and comprehensive toolset that offers a quantitative understanding of biomarkers of aging.

Adaptive immune responses against common viruses are sustained and functional in end-of-life patients

Viral infections occur with increased frequency in patients in palliative care, impacting their quality of life and increasing mortality rates. Still, the function of the immune system has never been thoroughly studied at the end of life. We investigated virus-specific humoral and cellular immune responses in elderly end-of-life patients (n = 38) and controls (n = 28). Virus-specific T cell responses were characterized using high-parameter flow cytometry, after stimulation with cytomegalovirus (CMV) and human coronavirus OC43 peptides. Although some virus-specific T cells from patients exhibited elevated expression of costimulatory and coinhibitory molecules, their functional profile remained largely intact compared to controls. The expression of the cytotoxic markers Granzyme B, CD107a, and 2B4 on CMV-specific T cells correlated closely with survival time. Significantly, our data demonstrate that both humoral and cellular immunity remain responsive and functional against common viruses in end-of-life patients.

Aging, frailty, and their effects on motor performance: evidence from kinematic analysis

INTRODUCTION

Aging is commonly linked to motor impairment. However, the relationship between motor performance across age groups and frailty remains unexplored through objective analysis.

OBJECTIVE

To kinematically evaluate motor performance in older and younger adults and investigate its potential connection to frailty.

METHODS

We included 65 healthy subjects (40 females, age range 46-83 years). We used kinematic techniques to study finger-tapping and measure several movement parameters, i.e., number of movements, movement rhythm, amplitude and velocity, as well as progressive reduction in amplitude and velocity during movement repetition (sequence effect). The frailty status was evaluated using a 40-item Frailty Index (FI). We also evaluated cognitive functions, using the Mini Mental State Examination (MMSE) and the Frontal Assessment Battery (FAB). We tested possible relationships between clinical and kinematic data using Spearman's correlation.

RESULTS

A key finding was a significant difference in movement velocity between younger and older adults, with the latter exhibiting lower values (P = 0.014). Accordingly, age significantly correlated with movement velocity (ρ = -0.335, P = 0.037). Among older adults, movement velocity was also found to correlate with frailty (ρr = -0.297, P = 0.033), thus indicating that greater frailty is associated with more impaired motor performance.

CONCLUSIONS

The relationship between the age-related slowed movement execution and frailty suggests that motor performance may serve as a sensitive indicator of physical vulnerability in aging populations.

Blood-based biomarkers of frailty in older patients with cancer

PURPOSE OF REVIEW

This review aims to evaluate the current evidence on blood-based biomarkers for frailty detection in older cancer patients. It explores the potential of various biomarkers, including inflammatory markers and microRNAs (miRNAs), to serve as indicators of frailty and examines the limitations of existing studies. The review also highlights the need for further research to validate these biomarkers and improve their clinical applicability.

RECENT FINDINGS

Recent studies have examined blood biomarkers associated with frailty in older cancer patients. Findings suggest that elevated granulocyte levels and lower macrophage-derived stem cells and regulatory T cells are linked to frailty. Inflammatory biomarkers such as interleukin-6 and specific miRNAs, as well as higher neutrophil-to-lymphocyte ratios, have also been identified as potential indicators of frailty. While these biomarkers show promise, no single marker has proven sufficient, and combining them may improve frailty detection. Further research is needed to validate their clinical usefulness in this population.

SUMMARY

Blood-based biomarkers show potential for detecting frailty in older patients with cancer, but further research is needed, particularly beyond an inflammatory focus and with more robust study designs.

Effects of Twelve Weeks of Square Stepping Exercises on Physical and Cognitive Function and Plasma Content of SMP30: A Randomised Control Trial

BACKGROUND

Ageing and sedentary lifestyles affect physical and cognitive function and markers of frailty, increasing the risk of falls in older adults and affecting their quality of life. The aim of this study was to evaluate the effects of a Square Step Exercise programme on physical and cognitive function and plasma SMP30 levels for the prevention of falls in older adults.

METHODS

A randomised controlled trial was designed with 44 participants assigned to an experimental group (SSE group) and a control group. The SSE group performed SSE sessions twice a week for three months, with a follow-up in the fourth month. The assessments of physical function included tests such as the Four-Square Step Test, Brisk Walking and its dual-task variant, Time Up and Go and its imagined and dual-task variants, 30 s Sit-to-Stand and its dual-task and imagined variants and a 6 min walking test. Questionnaires were also used to assess the risk and fear of falling. Resting EEG activity was also recorded to assess electrocortical brain activity. SMP30 levels were measured by Western blotting.

RESULTS

The SSE group showed significant improvements compared to the control group in the Four-Square Step Test (p < 0.001), Brisk Walking (p < 0.05) and reduction in the fear of falling (p < 0.001) after the training programme, but these adaptations were not maintained one month after the programme ended (p < 0.05). No significant changes were observed in the remaining variables of physical function, cognitive function, fall risk questionnaire, EEG activity or plasma levels of SMP30 compared to the control group (p > 0.05).

CONCLUSIONS

The SSE programme showed efficacy in improving balance, gait speed and reducing fear of falling in older adults but did not show improvement over the control group in other areas of physical or cognitive function or plasma SMP30 levels for fall prevention.

Geroprotective effects of GdVO4:Eu3 + nanoparticles, metformin and calorie restriction in male rats with accelerated aging induced by overnutrition in early postnatal ontogenesis

GdVO4:Eu3+ nanoparticles (OVNPs) have previously been shown to exhibit anti-aging effects in old rats.The accelerated aging model (overnutrition in early postnatal ontogenesis (POF)) was used to confirm the effect of OVNPs as a potential geroprotector. A comparative study of the effect of OVNPs, calorierestriction (CR) and CR-mimetic-metformin was carried out using a number of criteria: survival, prooxidant-antioxidant balance in the liver and blood, physiological parameters of male Wistar rats with accelerated aging. It was found that the survival of rats with POF was lower than that of control animals.It was found that the rate of superoxide radical formation and the content of lipid hydroperoxides in the mitochondria and microsomes of the liver and blood serum of rats with POF were higher, and the activities of glutathione peroxidases and the GSH content were significantly lower than in the control animals.It was also found that POF leads to perturbation of physiological parameters (body weight, liver weight, liver mass coefficient, body temperature and blood thyroxine concentration) characterizing the quality of life. Long-term use of OVNPs, CR or metformin in rats with accelerated aging normalized the imbalance of the prooxidant-antioxidant system, improved the physiological parameters, and increased the survival of these experimental animals. Moreover, the increase in survival was most pronounced with the use of CR and OVNPs. Considering our results andthe inadmissibility of long-term use of CR, it should be concluded that GdVO4:Eu3+ nanoparticles are promising for the development of agents that slow down the accelerated aging of an organism.

Identifying and Estimating Frailty Phenotypes by Vocal Biomarkers: Cross-Sectional Study

BACKGROUND

Researchers have developed a variety of indices to assess frailty. Recent research indicates that the human voice reflects frailty status. Frailty phenotypes are seldom discussed in the literature on the aging voice.

OBJECTIVE

This study aims to examine potential phenotypes of frail older adults and determine their correlation with vocal biomarkers.

METHODS

Participants aged ≥60 years who visited the geriatric outpatient clinic of a teaching hospital in central Taiwan between 2020 and 2021 were recruited. We identified 4 frailty phenotypes: energy-based frailty, sarcopenia-based frailty, hybrid-based frailty-energy, and hybrid-based frailty-sarcopenia. Participants were asked to pronounce a sustained vowel "/a/" for approximately 1 second. The speech signals were digitized and analyzed. Four voice parameters-the average number of zero crossings (A1), variations in local peaks and valleys (A2), variations in first and second formant frequencies (A3), and spectral energy ratio (A4)-were used for analyzing changes in voice. Logistic regression was used to elucidate the prediction model.

RESULTS

Among 277 older adults, an increase in A1 values was associated with a lower likelihood of energy-based frailty (odds ratio [OR] 0.81, 95% CI 0.68-0.96), whereas an increase in A2 values resulted in a higher likelihood of sarcopenia-based frailty (OR 1.34, 95% CI 1.18-1.52). Respondents with larger A3 and A4 values had a higher likelihood of hybrid-based frailty-sarcopenia (OR 1.03, 95% CI 1.002-1.06) and hybrid-based frailty-energy (OR 1.43, 95% CI 1.02-2.01), respectively.

CONCLUSIONS

Vocal biomarkers might be potentially useful in estimating frailty phenotypes. Clinicians can use 2 crucial acoustic parameters, namely A1 and A2, to diagnose a frailty phenotype that is associated with insufficient energy or reduced muscle function. The assessment of A3 and A4 involves a complex frailty phenotype.

Association of frailty and serum neurofilament light chain levels: the mediating role of estimated glomerular filtration rate

Background

Both frailty and elevated serum neurofilament light chain (sNfL) levels are linked to cognitive impairment. However, evidence of their relationship is lacking, and whether it was mediated by renal function was unknown. This study aimed to investigate the association between frailty and sNfL levels in a representative U.S. population, and to explore the potential mediating role of estimated glomerular filtration rate (eGFR) in this relationship.

Methods

Data from 1,782 participants aged 20-75 years in the 2013-2014 National Health and Nutrition Examination Survey (NHANES) were analyzed. Frailty was assessed using a 49-item frailty index, and participants were categorized as non-frail, pre-frail, or frail. sNfL levels were measured using acoustic emission technology. Multivariable linear regression models and restricted cubic spline analyses were employed to examine the associations between frailty, eGFR, and sNfL levels. Mediation analysis was conducted to evaluate the role of eGFR in the frailty-sNfL relationship.

Results

The prevalence of pre-frailty and frailty was 45.39 and 11.60%, respectively. A significant positive association was observed between frailty score and sNfL levels (adjusted β: 39.97, SE: 11.07, p = 0.003), with a linear relationship confirmed by restricted cubic spline analysis. Frail individuals had significantly higher sNfL levels compared to non-frail participants (adjusted β: 11.86, SE: 5.42, p = 0.04). eGFR was negatively associated with sNfL levels (adjusted β: -0.23, SE: 0.05, p < 0.001). Mediation analysis revealed that eGFR accounted for 12.52% of the total effect of frailty on sNfL levels (p < 0.0001).

Conclusion

This study demonstrates a significant association between frailty and elevated sNfL levels in a representative U.S. population, with eGFR partially mediating this relationship. These findings suggest that sNfL may serve as a potential biomarker for frailty-related neuronal damage and highlight the importance of kidney function in this association. Further research is warranted to explore the clinical implications of these findings in frailty assessment and management strategies.

Physiological changes associated with aging: Identification of novel biomarkers for frailty syndrome in women

This study explores the physiological changes associated with aging that lead to frailty syndrome, characterized by reduced vitality and degeneration across multiple bodily systems, increasing susceptibility to various pathologies. While established scales like the Fried Phenotype and Frailty Trait Scale (FTS) are commonly used for assessing frailty, incorporating biomarkers is crucial for accurate diagnosis and prognosis. Our research examines plasma oxylipin levels in frail elderly individuals to identify novel biomarkers. Diagnostic criteria for frailty included assessments using the Fried Phenotype and FTS-5, with blood samples collected from 71 elderly participants (50 women and 21 men) with mean ages of 73.6 ± 5.9 and 76.2 ± 6.2 years, respectively. Women exhibited elevated platelet counts (p-value 0.0035). The significant differences in oxylipin concentrations associated with the Fried Phenotype were particularly noteworthy, predominantly observed in women. Specifically, in women, decreased grip strength (<15 kg) and slow gait speed (<0.8 m/s) correlated with increased levels of thromboxane B2 (TxB2) and 7-HDoHE (p-values 0.0404, 0.0300, 0.0033, and 0.0033, respectively). Additionally, elevated 7-HDoHE levels correlated with a BMI exceeding 28 kg/m2 (p-value 0.0123) and Physical Activity Scale for the Elderly (PASE) scores surpassing 5 points (p-value 0.0134) in women. In summary, our findings emphasize that frail older individuals, particularly women, exhibit higher levels of TxB2 and 7-HDoHE compared to their non-frail counterparts, aligning with established frailty classification and scale parameters, suggesting their potential as indicative biomarkers.

Understanding the Role of Oxidative Stress in Platelet Alterations and Thrombosis Risk among Frail Older Adults

Frailty and cardiovascular diseases are increasingly prevalent in aging populations, sharing common pathological mechanisms, such as oxidative stress. The evidence shows that these factors predispose frail individuals to cardiovascular diseases but also increase the risk of thrombosis. Considering this background, this review aims to explore advances regarding the relationship between oxidative stress, platelet alterations, and cardiovascular diseases in frailty, examining the role of reactive oxygen species overproduction in platelet activation and thrombosis. The current evidence shows a bidirectional relationship between frailty and cardiovascular diseases, emphasizing how frailty not only predisposes individuals to cardiovascular diseases but also accelerates disease progression through oxidative damage and increased platelet function. Thus, oxidative stress is the central axis in the increase in platelet activation and secretion and the inadequate response to acetylsalicylic acid observed in frail people by mitochondrial mechanisms. Also, key biomarkers of oxidative stress, such as isoprostanes and derivate reactive oxygen metabolites, can be optimal predictors of cardiovascular risk and potential targets for therapeutic intervention. The potential of antioxidant therapies in mitigating oxidative stress and improving cardiovascular clinical outcomes such as platelet function is promising in frailty, although further research is necessary to establish the efficacy of these therapies. Understanding these mechanisms could prove essential in improving the health and quality of life of an aging population faced with the dual burden of frailty and cardiovascular diseases.

Frailty and brain changes in older adults without cognitive impairment: A scoping review

Little is known about changes in the brain associated with frailty, in particular, which brain areas could be related to frailty in older people without cognitive impairment. This scoping review mapped evidence on functional and/or structural brain changes in frail older adults without cognitive impairment. The methodology proposed by the JBI® was used in this study. The search in PubMed, PubMed PMC, BVS/BIREME, EBSCOHOST, Scopus, Web of Science, Embase, and PROQUEST was conducted up to January 2023. Studies included following the population, concepts, context and the screening and data extraction were performed by two independent reviewers. A total of 9,912 records were identified, 5,676 were duplicates and were excluded. The remaining articles were screened; 31 were read in full and 17 articles were included. The results showed that lesions in white matter hyperintensities, reduced volume of the hippocampus, cerebellum, middle frontal gyrus, low gray matter volume, cortical atrophy, decreased connectivity of the supplementary motor area, presence of amyloid-beta peptide (aβ) in the anterior and posterior putamen and precuneus regions were more frequently observed in frail older adults, compared with non-frail individuals. Studies have suggested that such findings may be of neurodegenerative or cerebrovascular origin. The identification of these brain alterations in frail older adults through neuroimaging studies contributes to our understanding of the underlying mechanisms of frailty. Such findings may have implications for the early detection of frailty and implementation of intervention strategies.

Biomarkers of frailty

Several biomarkers have been proposed to identify frailty, a multisystemic age-related syndrome. However, the complex pathophysiology and the absence of a consensus on a comprehensive and universal definition make it challenging to pinpoint a singular biomarker or set of biomarkers that conclusively characterize frailty. This review delves into the main laboratory biomarkers, placing special emphasis on those associated with various pathways closely tied to the frailty condition, such as inflammation, oxidative stress, mitochondrial dysfunction, metabolic and endocrine alterations and microRNA. Additionally, we provide a summary of different clinical biomarkers encompassing different tools that have been proposed to assess frailty. We further address various imaging biomarkers such as Dual Energy X-ray Absorptiometry, Bioelectrical Impedance analysis, Computed Tomography and Magnetic Resonance Imaging, Ultrasound and D3 Creatine dilution. Intervention to treat frailty, including non-pharmacological ones, especially those involving physical exercise and nutrition, and pharmacological interventions, that include those targeting specific mechanisms such as myostatin inhibitors, insulin sensitizer metformin and with special relevance for hormonal treatments are mentioned. We further address the levels of different biomarkers in monitoring the potential positive effects of some of these interventions. Despite the availability of numerous biomarkers, their performance and usefulness in the clinical arena are far from being satisfactory. Considering the multicausality of frailty, there is an increasing need to assess the role of sets of biomarkers and the combination between laboratory, clinical and image biomarkers, in terms of sensitivity, specificity and predictive values for the diagnosis and prognosis of the different outcomes of frailty to improve detection and monitoring of older people with frailty or at risk of developing it, being this a need in the everyday clinical practice.

Exploring role of natural compounds in molecular alterations associated with brain ageing: A perspective towards nutrition for ageing brain

Aging refers to complete deterioration of physiological integrity and function. By midcentury, adults over 60 years of age and children under 15 years will begin to outnumber people in working age. This shift will bring multiple global challenges for economy, health, and society. Eventually, aging is a natural process playing a vital function in growth and development during pediatric stage, maturation during adult stage, and functional depletion. Tissues experience negative consequences with enhanced genomic instability, deregulated nutrient sensing, mitochondrial dysfunction, and decline in performance on cognitive tasks. As brain ages, its volume decreases, neurons & glia get inflamed, vasculature becomes less developed, blood pressure increases with a risk of stroke, ischemia, and cognitive deficits. Diminished cellular functions leads to progressive reduction in functional and emotional capacity with higher possibility of disease and finally death. This review overviews cellular as well as molecular aspects of aging, biological pathway related to accelerated brain aging, and strategies minimizing cognitive aging. Age-related changes include altered bioenergetics, decreased neuroplasticity and flexibility, aberrant neural activity, deregulated Ca2+ homeostasis in neurons, buildup of reactive oxygen species, and neuro-inflammation. Unprecedented progress has been achieved in recent studies, particularly in terms of how herbal or natural substances affect genetic pathways and biological functions that have been preserved through evolution. Herein, the present work provides an overview of ageing and age-related disorders and explore the molecular mechanisms that underlie therapeutic effects of herbal and natural chemicals on neuropathological signs of brain aging.

Prognostic accuracy of 70 individual frailty biomarkers in predicting mortality in the Canadian Longitudinal Study on Aging

The frailty index (FI) uses a deficit accumulation approach to derive a single, comprehensive, and replicable indicator of age-related health status. Yet, many researchers continue to seek a single "frailty biomarker" to facilitate clinical screening. We investigated the prognostic accuracy of 70 individual biomarkers in predicting mortality, comparing each with a composite FI. A total of 29,341 individuals from the comprehensive cohort of the Canadian Longitudinal Study on Aging were included (mean, 59.4 ± 9.9 years; 50.3% female). Twenty-three blood-based biomarkers and 47 test-based biomarkers (e.g., physical, cardiac, cardiology) were examined. Two composite FIs were derived: FI-Blood and FI-Examination. Mortality status was ascertained using provincial vital statistics linkages and contact with next of kin. Areas under the curve were calculated to compare prognostic accuracy across models (i.e., age, sex, biomarker, FI) in predicting mortality. Compared to an age-sex only model, the addition of individual biomarkers demonstrated improved model fit for 24/70 biomarkers (11 blood, 13 test-based). Inclusion of FI-Blood or FI-Examination improved mortality prediction when compared to any of the 70 biomarker-age-sex models. Individual addition of seven biomarkers (walking speed, chair rise, time up and go, pulse, red blood cell distribution width, C-reactive protein, white blood cells) demonstrated an improved fit when added to the age-sex-FI model. FI scores had better mortality risk prediction than any biomarker. Although seven biomarkers demonstrated improved prognostic accuracy when considered alongside an FI score, all biomarkers had worse prognostic accuracy on their own. Rather than a single biomarker test, implementation of routine FI assessment in clinical settings may provide a more accurate and reliable screening tool to identify those at increased risk of adverse outcomes.

Nutritional and inflammation factors associated with current frailty level and effect of co-morbidities on the progression of frailty

AIM

Frailty is defined as extreme vulnerability, a syndrome that exposes the individual to a higher risk of disability. While risk factors for frailty have been gradually uncovered, the full identification of biochemical factors and co-morbidities influencing frailty remains incomplete.

METHODS

Cross-sectional and longitudinal analyses were performed to elucidate the risk factors for the prevalence and progression of frailty. The study included 1035 Japanese female outpatients. At baseline, biochemical markers were measured. Co-morbidities included diabetes mellitus, dyslipidemia, hypertension, vertebral osteoarthritis, and osteoporosis. Frailty levels were assessed using frailty scores ranging from 0 to 5. Prevalence of frailty was judged by a score of 3 or above, and progression was judged by an increase in the frailty score during the observation period. Multiple regression analysis was used for the cross-sectional analysis, and the Cox hazard model was used for the longitudinal analysis.

RESULTS

Of the 1035 selected participants, 212 were diagnosed with frailty. Advanced age and log IL-6 and branched-chain amino acids (BCAA) levels were significant independent risk factors for frailty. Subjects were followed for 7.7 ± 5.9 years and progression was observed in 130 subjects. Older age, the absence of hyperlipidemia, the presence of osteoporosis, and lower frailty scores were identified as significant risk factors for frailty progression.

CONCLUSIONS

Inflammatory and nutritional markers exhibited significant associations with the current frailty status, whereas co-morbidities such as osteoporosis or hyperlipidemia emerged as independent risk or protective factors of future frailty progression. Geriatr Gerontol Int 2024; 24: 523-528.

Decreased mitochondrial respiration associates with frailty in community-dwelling older adults

Aging population has led to an increased prevalence of chronic and degenerative pathologies. A manifestation of unhealthy aging is frailty, a geriatric syndrome that implies a non-specific state of greater vulnerability. Currently, methods for frailty diagnosis are based exclusively on clinical observation. The aim of this study is to determine whether the bioenergetic capacity defined as mitochondrial oxygen consumption rate (OCR) of peripheral circulation mononuclear cells (PBMC) associates with the frailty phenotype in older adults and with their nutritional status. This is a cross-sectional analytic study of 58 participants 70 years and older, 18 frail and 40 non-frail adults, from the ALEXANDROS cohort study, previously described. Participants were characterized through sociodemographic and anthropometric assessments. Frail individuals displayed a higher frequency of osteoporosis and depression. The mean age of the participants was 80.2 ± 5.2 years, similar in both groups of men and women. Regarding the nutritional status defined as the body mass index, most non-frail individuals were normal or overweight, while frail participants were mostly overweight or obese. We observed that OCR was significantly decreased in frail men (p < 0.01). Age was also associated with significant differences in oxygen consumption in frail patients, with lower oxygen consumption being observed in those over 80 years of age. Therefore, the use of PBMC can result in an accessible fingerprint that may identify initial stages of frailty in a minimally invasive way.

Focus on senescence: Clinical significance and practical applications

The older population is increasing worldwide, and life expectancy is continuously rising, predominantly thanks to medical and technological progress. Healthspan refers to the number of years an individual can live in good health. From a gerontological viewpoint, the mission is to extend the life spent in good health, promoting well-being and minimizing the impact of aging-related diseases to slow the aging process. Biologically, aging is a malleable process characterized by an intra- and inter-individual heterogeneous and dynamic balance between accumulating damage and repair mechanisms. Cellular senescence is a key component of this process, with senescent cells accumulating in different tissues and organs, leading to aging and age-related disease susceptibility over time. Removing senescent cells from the body or slowing down the burden rate has been proposed as an efficient way to reduce age-dependent deterioration. In animal models, senotherapeutic molecules can extend life expectancy and lifespan by either senolytic or senomorphic activity. Much research shows that dietary and physical activity-driven lifestyle interventions protect against senescence. This narrative review aims to summarize the current knowledge on targeting senescent cells to reduce the risk of age-related disease in animal models and their translational potential for humans. We focused on studies that have examined the potential role of senotherapeutics in slowing the aging process and modifying age-related disease burdens. The review concludes with a general discussion of the mechanisms underlying this unique trajectory and its implications for future research.

Use of dried blood spots for monitoring inflammatory and nutritional biomarkers in the elderly

OBJECTIVES

Blood microsampling, particularly dried blood spots (DBSs), is an attractive minimally-invasive approach that is well suited for home sampling and predictive medicine associated with longitudinal follow-up of the elderly. However, in vitro diagnostic quantification of biomarkers from DBS poses a major challenge. Clinical mass spectrometry can reliably quantify blood proteins in various research projects. Our goal here was to use mass spectrometry of DBS in a real-world clinical setting and compared it to the standard immunoassay method. We also sought to correlate DBS mass spectrometry measurements with clinical indices.

METHODS

A clinical trial of diagnostic equivalence was conducted to compare conventional venous samples quantified by immunoassay and DBSs quantified by mass spectrometry in an elderly population. We assayed three protein biomarkers of nutritional and inflammatory status: prealbumin (transthyretin), C-reactive protein, and transferrin.

RESULTS

The analysis of DBSs showed satisfactory variability and low detection limits. Statistical analysis confirmed that the two methods give comparable results at clinical levels of accuracy. In conclusion, we demonstrated, in a real-life setting, that DBSs can be used to measure prealbumin, CRP and transferrin, which are commonly used markers of nutritional status and inflammation in the elderly. However, there was no correlation with patient frailty for these proteins.

CONCLUSIONS

Early detection and regular monitoring of nutritional and inflammatory problems using DBS appear to be clinically feasible. This could help resolve major public health challenges in the elderly for whom frailty leads to serious risks of health complications.

Demographic and biological factors in interrelationships between physical, cognitive, psychological, and social frailty in community-dwelling older adults: Data from the Birjand Longitudinal Aging Study (BLAS)

Complex interrelationships may exist among different types of frailty. This study aimed to evaluate the demographic and biological factors that influence the different types of frailty in community-dwelling older adults in Iran through a cross-sectional analysis of data obtained from the Birjand Longitudinal Aging Study. This study is an ongoing cohort study of people aged 60 years and over and employed a multistage stratified cluster random sampling. Anthropometric measures were obtained by nurses. The "Fried frailty phenotype" was defined as physical frailty. Cognitive frailty was assessed using the Mini-Mental State Examination. Social frailty was evaluated by some questions, and psychological frailty was assessed using a patient health questionnaire. Blood samples were taken after overnight fasting. All statistical analyses were performed using Stata12 (Texas, USA) and Python. Some type of frailty had been experienced by 62.27 % of the older adults. Cognitive frailty was the dominant type of frailty (55.69 %). Based on multivariate regression analysis, age, sex, education, and marital status were the influencing factors in all types of frailty. Network analysis revealed that physical, cognitive, psychological, and social frailty had synergistic effects on each other, and age and sex had dominant interactions with frailty types. Cognitive frailty was dominant compared with other types of frailty, indicating the need to detect cognitive frailty at the earliest stage and to implement an appropriate program to manage cognitive frailty in older adults.

The Association Between Habitual Tea Consumption and Frailty Transition in Community-Dwelling Older Adults: A Prospective Cohort Study

OBJECTIVES

To investigate the association between habitual tea consumption and transitions between frailty states among older adults in China.

DESIGN

A prospective cohort study based on the Chinese Longitudinal Healthy Longevity Study.

SETTING AND PARTICIPANTS

A total of 23,720 older adults aged ≥65 years with complete data regarding frailty status and tea consumption were recruited.

METHODS

The frequency and consistency of tea consumption were introduced to evaluate levels of tea consumption. The frailty index was used to define frailty status (frail and nonfrail). Frailty transition was classified into remaining nonfrail, improvement, worsening, and remaining frail groups. Logistic regression models were applied.

RESULTS

The overall frailty prevalence at baseline was 19.1%, being lower among consistent daily tea drinkers (12.5%) and higher among non-tea drinkers (21.9%). Logistic regression analyses showed that the risk of frailty was significantly reduced among consistent daily tea drinkers after adjusting for all confounders [odds ratio (OR), 0.81; 95% CI, 0.67-0.98]. During the 3-year follow-up, improvement in frailty status was more common among consistent daily tea drinkers (50.9%) than non-tea drinkers (40.9%), and this trend was opposite in participants with worsened frailty status (consistent daily tea drinkers: 12.2%) vs non-tea drinkers: 19.2%). Further analysis showed that consistent daily tea drinkers were significantly associated with improvement in frailty status (OR, 3.24; 95% CI, 1.02-10.31) and remaining in a nonfrail state (OR, 1.35; 95% CI, 1.00-1.83). In addition, daily tea consumption was observed to be positively associated with remaining in a nonfrail state and inversely associated with worsened frailty status in men, but not in women.

CONCLUSIONS AND IMPLICATIONS

Older people consuming tea daily tend to have an improved frailty status in the future. Men with daily tea consumption were less likely to have a worsened frailty status. Advocating for the traditional lifestyle of drinking tea could be a promising way to advance healthy aging for older adults.

Biomarkers of aging in frailty and age-associated disorders: State of the art and future perspective

According to the Geroscience concept that organismal aging and age-associated diseases share the same basic molecular mechanisms, the identification of biomarkers of age that can efficiently classify people as biologically older (or younger) than their chronological (i.e. calendar) age is becoming of paramount importance. These people will be in fact at higher (or lower) risk for many different age-associated diseases, including cardiovascular diseases, neurodegeneration, cancer, etc. In turn, patients suffering from these diseases are biologically older than healthy age-matched individuals. Many biomarkers that correlate with age have been described so far. The aim of the present review is to discuss the usefulness of some of these biomarkers (especially soluble, circulating ones) in order to identify frail patients, possibly before the appearance of clinical symptoms, as well as patients at risk for age-associated diseases. An overview of selected biomarkers will be discussed in this regard, in particular we will focus on biomarkers related to metabolic stress response, inflammation, and cell death (in particular in neurodegeneration), all phenomena connected to inflammaging (chronic, low-grade, age-associated inflammation). In the second part of the review, next-generation markers such as extracellular vesicles and their cargos, epigenetic markers and gut microbiota composition, will be discussed. Since recent progresses in omics techniques have allowed an exponential increase in the production of laboratory data also in the field of biomarkers of age, making it difficult to extract biological meaning from the huge mass of available data, Artificial Intelligence (AI) approaches will be discussed as an increasingly important strategy for extracting knowledge from raw data and providing practitioners with actionable information to treat patients.

Skin Cancer Microenvironment: What We Can Learn from Skin Aging?

Aging is a natural intrinsic process associated with the loss of fibrous tissue, a slower cell turnover, and a reduction in immune system competence. In the skin, the continuous exposition of environmental factors superimposes extrinsic damage, mainly due to ultraviolet radiation causing photoaging. Although not usually considered a pathogenic event, photoaging affects cutaneous biology, increasing the risk of skin carcinogenesis. At the cellular level, aging is typified by the rise of senescence cells a condition characterized by reduced or absent capacity to proliferate and aberrant hyper-secretory activity. Senescence has a double-edged sword in cancer biology given that senescence prevents the uncontrolled proliferation of damaged cells and favors their clearance by paracrine secretion. Nevertheless, the cumulative insults and the poor clearance of injured cells in the elderly increase cancer incidence. However, there are not conclusive data proving that aged skin represents a permissive milieu for tumor onset. On the other hand, tumor cells are capable of activating resident fibroblasts onto a pro-tumorigenic phenotype resembling those of senescent fibroblasts suggesting that aged fibroblasts might facilitate cancer progression. This review discusses changes that occur during aging that can prime neoplasm or increase the aggressiveness of melanoma and non-melanoma skin cancer.

Patterns of Dietary Blood Markers Are Related to Frailty Status in the FRAILOMIC Validation Phase

The influence of nutritional factors on frailty syndrome is still poorly understood. Thus, we aimed to confirm cross-sectional associations of diet-related blood biomarker patterns with frailty and pre-frailty statuses in 1271 older adults from four European cohorts. Principal component analysis (PCA) was performed based on plasma levels of α-carotene, β-carotene, lycopene, lutein + zeaxanthin, β-cryptoxanthin, α-tocopherol, γ-tocopherol and retinol. Cross-sectional associations between biomarker patterns and frailty status, according to Fried's frailty criteria, were assessed by using general linear models and multinomial logistic regression models as appropriate with adjustments for the main potential confounders. Robust subjects had higher concentrations of total carotenoids, β-carotene and β-cryptoxanthin than frail and pre-frail subjects and had higher lutein + zeaxanthin concentrations than frail subjects. No associations between 25-Hydroxyvitamin D3 and frailty status were observed. Two distinct biomarker patterns were identified in the PCA results. The principal component 1 (PC1) pattern was characterized by overall higher plasma levels of carotenoids, tocopherols and retinol, and the PC2 pattern was characterized by higher loadings for tocopherols, retinol and lycopene together and lower loadings for other carotenoids. Analyses revealed inverse associations between PC1 and prevalent frailty. Compared to participants in the lowest quartile of PC1, those in the highest quartile were less likely to be frail (odds ratio: 0.45, 95% CI: 0.25-0.80, p = 0.006). In addition, those in the highest quartile of PC2 showed higher odds for prevalent frailty (2.48, 1.28-4.80, p = 0.007) than those in the lowest quartile. Our findings strengthen the results from the first phase of the FRAILOMIC project, indicating carotenoids are suitable components for future biomarker-based frailty indices.