Energy metabolism and frailty: The potential role of exercise-induced myokines - A narrative review

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.

Exerkines and cardiometabolic benefits of exercise: from bench to clinic

Regular exercise has both immediate and long-lasting benefits on cardiometabolic health, and has been recommended as a cornerstone of treatment in the management of diabetes and cardiovascular conditions. Exerkines, which are defined as humoral factors responsive to acute or chronic exercise, have emerged as important players conferring some of the multiple cardiometabolic benefits of exercise. Over the past decades, hundreds of exerkines released from skeletal muscle, heart, liver, adipose tissue, brain, and gut have been identified, and several exerkines (such as FGF21, IL-6, and adiponectin) have been exploited therapeutically as exercise mimetics for the treatment of various metabolic and cardiovascular diseases. Recent advances in metagenomics have led to the identification of gut microbiota, a so-called "hidden" metabolic organ, as an additional class of exerkines determining the efficacy of exercise in diabetes prevention, cardiac protection, and exercise performance. Furthermore, multiomics-based studies have shown the feasibility of using baseline exerkine signatures to predict individual responses to exercise with respect to metabolic and cardiorespiratory health. This review aims to explore the molecular pathways whereby exerkine networks mediate the cardiometabolic adaptations to exercise by fine-tuning inter-organ crosstalk, and discuss the roadmaps for translating exerkine-based discovery into the therapeutic application and personalized medicine in the management of the cardiometabolic disease.

Physical activity and neurotrophic factors as potential drivers of neuroplasticity in Parkinson's Disease: A systematic review and meta-analysis

Parkinson's disease (PD) is a neurodegenerative disorder, characterized by motor and non-motor symptoms, that still lacks of a disease-modifying treatment. Consistent evidence proved the benefits of physical therapy on motor and non-motor symptoms in PD patients, leading the scientific community to propose physical activity as disease-modifying therapy for PD and suggesting the involvement of neurotrophic factors (NFs) as key mediators of neuroplasticity. However, the lack of standardized exercise training and methodological flaws of clinical trials have limited the evidence demonstrating the exercise-induced changes in serum and plasma neurotrophic factors concentration. A systematic search, covering 20 years of research in this field and including randomized and non-randomized controlled trials (RCTs and non-RCTs), which reported changes in serum and plasma NFs after a specific intervention, were reviewed. Pooled effect sizes (p-ESs) and 95% confidence intervals (95%CIs) were calculated using a random effects model with R software. A total of 18 articles, of which exercise programs of interventions were codified in terms of type, intensity and duration adopting a standardisation methodology, were included in the systematic review. Six papers, describing the effect of different training programs on BDNF and IGF-1 levels, were included and independently analysed in two meta-analyses. Quantitative analysis for BDNF indicated a statistically significant improvement in serum concentration of PD patients (MD: 5.99 ng/mL; 95%IC: 0.15 -11.83; I2 = 77%) performing physical activity compared with control conditions in RCTs. Preliminary evidence supported the hypothesis that a moderate intensity aerobic exercise (MIAE) would be necessary to induce the changes in NFs. However, sensitivity analysis of meta-analysis and the few studies included in subgroup analysis did not support these results. Alongside, meta-analysis followed by sensitivity analysis revealed a potential change in serum IGF-1 (MD: 33.47 ng/mL; 95%IC: 8.09-58.85) in PD patients performing physical activity with respect controls in RCT studies. Considering the limited evidence to support or refute the increase in NFs levels in PD patients performing physical activity, there is a need to develop a rigorous controlled randomized trial, with standardization for loading intensity of physical activity, greater sample size, and a correct stratification of PD patients to establish a well-defined correlation between physical activity and NFs levels.

Recent developments in frailty identification, management, risk factors and prevention: A narrative review of leading journals in geriatrics and gerontology

Frailty is an age-related clinical condition characterised by an increased susceptibility to stressors and an elevated risk of adverse outcomes such as mortality. In the light of global population ageing, the prevalence of frailty is expected to soar in coming decades. This narrative review provides critical insights into recent developments and emerging practices in frailty research regarding identification, management, risk factors, and prevention. We searched journals in the top two quartiles of geriatrics and gerontology (from Clarivate Journal Citation Reports) for articles published between 01 January 2018 and 20 December 2022. Several recent developments were identified, including new biomarkers and biomarker panels for frailty screening and diagnosis, using artificial intelligence to identify frailty, and investigating the altered response to medications by older adults with frailty. Other areas with novel developments included exercise (including technology-based exercise), multidimensional interventions, person-centred and integrated care, assistive technologies, analysis of frailty transitions, risk-factors, clinical guidelines, COVID-19, and potential future treatments. This review identified a strong need for the implementation and evaluation of cost-effective, community-based interventions to manage and prevent frailty. Our findings highlight the need to better identify and support older adults with frailty and involve those with frailty in shared decision-making regarding their care.

Subcutaneous adipose tissue alteration in aging process associated with thyroid hormone signaling

BACKGROUND

Functional changes in subcutaneous adipose tissue (SAT) occur earlier in the aging process and play an important role in the occurrence and development of age-related metabolic diseases. The mechanism of this phenomenon is still unclear, and the change in adipose tissue with age is poorly understood.

METHODS

We used transcriptome sequencing (RNA seq) to screen differentially expressed genes at the mRNA level, and analyzed the functional characteristics of the differential genes through GO and KEGG analysis in human SAT of all ages. In order to clarify the specific mechanism of the functional change, we analyzed the chromatin accessibility in the promoter region in the same SAT used in the RNA seq by the assay for transposase-accessible chromatin with high throughput sequencing (ATAC-seq) and obtained the functional genes in SAT changed with age. To verify these changes, we enlarged our sample content of human SAT. The primary mice adipocytes were extracted and stimulated by thyroid hormone of different concentration to construct an animal model, and the expression of the genes were determined through real-time Polymerase Chain Reaction(RT-PCR). The oxygen consumption test and immunofluorescence staining were used to determine the mitochondrial function of SAT.

RESULTS

RNA-seq showed characteristic gene expression of young and old human SAT, in which 331 genes were up-regulated and 349 genes were down-regulated. ATAC-seq, RNA-seq, combined with the mouse prediction model, determined the functional changed characteristics of seven genes. All these genes expressed differently in SAT of different ages, in which, NCF1, NLRP3, DUOX1 showed positive correlation with age; The expression of IFI30, P2RX1, P2RX6, PRODH, however, decreased with age. And all these genes showed dose dependent alternations under treatment of triiodothyroxine in mice SAT. The oxygen consumption rate revealed significant changes of the mitochondrial function and ROS accumulation in human SAT of different ages.

CONCLUSION

In elderly individuals, the function, in addition to distribution, of SAT undergoes significant changes, primarily in mitochondria, which may be due to insensitivity to thyroid hormone signaling. These results identified seven novel genes regulated by thyroid hormone, exhibiting significant changes in SAT of different age, and are probably related to the dysfunction of the aged SAT due to the mitochondrial damage and ROS accumulation.

The effects of physical exercise therapy on weight control: its regulation of adipocyte physiology and metabolic capacity

Factors associated with increased body mass, including dyslipidemia, hypertension, insulin resistance, vascular endothelial dysfunction and sleep disorders, may contribute to the exacerbation of cardiovascular disease. These health problems associated with obesity are caused by accumulated metabolism and physical and emotional stress. Lifestyle, especially exercise, is a major therapeutic strategy for the treatment and management of obesity-induced metabolic problems. Metabolic disease often co-occurs with abdominal obesity. Exercise is necessary for the treatment of obesity, diabetes and cardiovascular disease. A potential benefit of exercise is to promote fat burning and energy use increases both during exercise itself and in the post-exercise period. Exercise suppresses basal metabolic rate and also has many health benefits. Why should we exercise to lose weight? Does physical activity help lower blood pressure, blood cholesterol, and blood sugar? In this article, we review the positive effects of physical exercise on weight maintenance and weight loss, and the effectiveness of physical exercise on the treatment and prevention of metabolic syndrome.