Efficacy of L-carnitine supplementation on frailty status and its biomarkers, nutritional status, and physical and cognitive function among prefrail older adults: a double-blind, randomized, placebo-controlled clinical trial

A Hybrid Concept Analysis of Frailty Among Older Adults Living in the Community

AIM

To analyse the concept of frailty through a literature review and in-depth interviews.

DESIGN

A hybrid model of concept analysis.

METHODS

The theoretical phase identified 43 articles for reviewing the definition and measurement of frailty. Seven frail older adults were invited in the fieldwork phase for in-depth interviews. In the final analysis phase, results from the fieldwork and theoretical phases were integrated to obtain a final definition of frailty.

RESULTS

Attributes of frailty were heterogeneous, involving dynamic/bidirectional, multidimensional and multiple systems. The antecedents of the concept were exposure to various stimuli and challenges in responding to these stimuli. Consequences included losing autonomy and adverse health outcomes. Four themes of frailty were identified based on the fieldwork data: 'accumulation of functional decline', 'powerlessness of coping with', 'vicissitudes of lived experience' and 'loss of autonomy and positivity'.

CONCLUSIONS

The final definition of frailty was 'a dynamic and fluctuating process of powerlessness to manage biopsychosocial and environmental stimuli, involving functional decline and vicissitudes of life, which results in losing autonomy and positivity or adverse health outcomes'.

IMPLICATIONS FOR THE PROFESSION AND/OR PATIENT CARE

Characterising the definition of frailty is essential for nurses to address the lived experiences of older adults when providing person-centred care and for developing interventions that meet the needs of frail older adults.

IMPACT

Since some discrepancies existed in the definition of frailty from individual perception of older adults, combined in-depth interviews with a theoretical literature review were used to provide comprehensive insight. This concept analysis provides guidelines of training for nurses and opportunities to improving quality of life for community dwelling older adults.

REPORTING METHOD

N/A.

PATIENT OR PUBLIC CONTRIBUTION

No Patient or Public Contribution.

A Systematic Review of Frailty Interventions in Community-Based Low and Middle-Income Settings

Objective

To synthesise evidence on the effectiveness of frailty interventions among prefrail and frail community-dwelling older adults living in low and middle-income countries (LMICs).

Methods

The four electronic databases, Embase, Ovid MEDLINE, Global Health, and APA PsycINFO, were searched until 25 September 2023. This review's protocol was registered on PROSPERO (CRD42022309998). There was no publication time or language restriction. Inclusion criteria included randomised controlled trials and other intervention types of frailty interventions that focussed on community-dwelling older adults (mean age of at least 60 years) with prefrail or frail living in LMICs. The meta-analysis could not be conducted because of the heterogeneity of frailty interventions.

Results

This systematic review included fifteen studies: eleven were single-domain interventions (exercise, nutritional supplementation, and nurse home visits), and four were multidomain interventions (exercise plus nutrition and exercise plus mindfulness). Some evidence from high-quality studies showed that physical exercise interventions successfully addressed frailty.

Conclusion

This systematic review highlights the scarcity of evidence on frailty interventions in LMICs, making it difficult to evaluate their effectiveness. Additional research is needed to focus on specific types of interventions.

Effect of protein and amino acids supplements on muscle strength and physical performance: A scoping review of randomized controlled trials

Protein and amino acid supplementation is an effective intervention that significantly enhances physical function and reduces frailty and sarcopenia in older adults. This scoping review aims to map and synthesize the available evidence on the effects of various types of protein and amino acid supplementation in this population. Following the PRISMA-ScR guidelines, we conducted a literature search to identify clinical trials examining the effects of protein and amino acid supplementation, with or without physical exercise, on muscle strength, physical performance, and body composition in healthy, frail, or sarcopenic older adults. Our analysis of 80 trials with a total of 5290 participants examines the evidence for the effectiveness of protein supplementation in enhancing muscle strength and body composition. Whey protein, creatine, milk protein, leucine, essential amino acids, and soy protein were the most used types of protein, and our findings indicate that whey protein, creatine, and milk protein yield the best results when used in conjunction with resistance training. Additionally, leucine and milk protein have shown the potential to enhance body composition even without concurrent resistance training. In conclusion, studies on the effectiveness of whey protein in improving muscle strength and body composition in older adults with resistance training are inconsistent. More research is required to explore the potential benefits of soy and leucine-enriched supplements. Protein supplementation's impact on physical performance remains inconclusive. Further studies are needed to determine the effects of protein types and supplementation on muscle-related parameters in older adults.

Effect of Protein Supplementation on Orthostatic Hypotension in Older Adult Patients with Heart Failure

Purpose: Heart failure (HF) impairs physical performance and increases the incidence of orthostatic hypotension (OH). Individuals with OH have a higher risk of falls, which are a major source of morbidity and mortality in older adults. Dietary protein supplementation can improve physical performance in healthy older adult individuals; however, its effect on OH in older adult patients with HF is unknown. Methods: Twenty-one older adult patients with mild-to-moderate HF were randomized to placebo or protein supplementation. Dietary protein was supplemented with whey protein so the total protein intake for each participant was 1.2 g/kg bodyweight/day, plus 1 g/day of the amino acid l-carnitine for 16 weeks. Susceptibility to OH was assessed using a head-up tilt test, blood markers, and a functional test (6 min walk) at baseline and 16 weeks. Results: There were no differences in tilt test responses or 6 min walk test (6MWT) distances. The protein-supplement group had a significant increase in 6MWT pulse pressures post-walk after 16 weeks of treatment as compared to placebo. However, the tachycardia observed at baseline after 6MWT in the protein group was not seen at the end of the study. There was also a trend towards lower levels of brain naturetic peptide (proBNP) in the protein group vs. placebo at 16 weeks. Conclusions: The improved pulse-pressure response to exertion and positive trends in proBNP in this pilot study suggest that dietary supplementation may improve cardiovascular function and general health in individuals with HF and that larger future studies are justifiable.

Redox regulation: mechanisms, biology and therapeutic targets in diseases

Redox signaling acts as a critical mediator in the dynamic interactions between organisms and their external environment, profoundly influencing both the onset and progression of various diseases. Under physiological conditions, oxidative free radicals generated by the mitochondrial oxidative respiratory chain, endoplasmic reticulum, and NADPH oxidases can be effectively neutralized by NRF2-mediated antioxidant responses. These responses elevate the synthesis of superoxide dismutase (SOD), catalase, as well as key molecules like nicotinamide adenine dinucleotide phosphate (NADPH) and glutathione (GSH), thereby maintaining cellular redox homeostasis. Disruption of this finely tuned equilibrium is closely linked to the pathogenesis of a wide range of diseases. Recent advances have broadened our understanding of the molecular mechanisms underpinning this dysregulation, highlighting the pivotal roles of genomic instability, epigenetic modifications, protein degradation, and metabolic reprogramming. These findings provide a foundation for exploring redox regulation as a mechanistic basis for improving therapeutic strategies. While antioxidant-based therapies have shown early promise in conditions where oxidative stress plays a primary pathological role, their efficacy in diseases characterized by complex, multifactorial etiologies remains controversial. A deeper, context-specific understanding of redox signaling, particularly the roles of redox-sensitive proteins, is critical for designing targeted therapies aimed at re-establishing redox balance. Emerging small molecule inhibitors that target specific cysteine residues in redox-sensitive proteins have demonstrated promising preclinical outcomes, setting the stage for forthcoming clinical trials. In this review, we summarize our current understanding of the intricate relationship between oxidative stress and disease pathogenesis and also discuss how these insights can be leveraged to optimize therapeutic strategies in clinical practice.

Impact of multicomponent exercise and nutritional supplement interventions for improving physical frailty in community-dwelling older adults: a systematic review and meta-analysis

OBJECTIVE

To investigate the efficacy of both multicomponent exercise and nutritional interventions on frailty by conducting a systematic review and meta-analysis to examine changes in frailty incidence.

DESIGN

A systematic review and meta-analysis.

ELIGIBLE CRITERIA

The included studies were limited to original controlled trials focused on frailty interventions in older adults aged 65 years and over. The studies involved only participants with specific diseases, and those recovering from surgery or being hospitalized were excluded.

INFORMATION SOURCES

A systematic search was performed on three databases: PUBMED, EMBASE, and Cumulative Index to Nursing and Allied Health, with the latest search in October 2024. Three authors independently extracted the data using a standardized data collection form. Relative risks were used as a summary measure. Pooled-effect estimates of each outcome were calculated by the random-effects meta-analysis.

RESULTS

After searching three databases, 5327 records were identified. After removing duplicates and screening the titles and abstracts, 19 multicomponent exercise studies and 7 nutritional intervention studies were eligible. In a pooled analysis of 18 multicomponent exercise RCTs, including a total of 3457 older adults, the multicomponent exercises showed a clinically significant reduction in frailty risk by relative change 55% times (95% CI 45% to 67%, p value < 0.001). The subgroup analysis of combinations of macronutrients and micronutrients also demonstrated statistically significant decrease in frailty risk by relative change 28% times (95% CI 11% to 72%, p value = 0.008).

CONCLUSION

Multicomponent exercises can effectively improve physical frailty, regardless of the duration and types of the activities, whereas the efficacy of nutritional supplements remains unclear. Personalized multicomponent approaches that incorporate both exercises and nutritional supplements have promised to enhance effectiveness in reducing frailty, thus warranting further investigation.

TRIAL REGISTRATION

The study was registered on 12 September 2022, under PROSPERO registration number CRD42022357357.

Impact of Possible Sarcopenia and Nutritional Status on Postoperative Quick Disabilities of the Arm, Shoulder, and Hand Score in Geriatric Women With Distal Radius Fracture

PURPOSE

Distal radius fracture (DRF), sarcopenia, and malnutrition have been reported to be interrelated. However, there are few reports on the effects of sarcopenia and malnutrition on DRF patients' postoperative outcomes. This study examined the healthy-side grip strength and preoperative blood tests to determine the presence of possible sarcopenia (PS) and malnutrition in geriatric women with DRF and their impact on postoperative functional outcomes.

METHODS

Fifty-five woman older than 60 years treated with volar-locking plate fixation for low-energy DRF from standing-level falls were retrospectively studied. Based on the criteria of The Asian Working Group for Sarcopenia 2019, patients with a healthy-side grip strength <18 kg were defined as PS. Nutritional assessment was performed using Onodera's Prognostic Nutritional Index (PNI) before surgery, with a value <50 defined as malnutrition. The Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) was used for functional assessment at 1 year after surgery. Patients were divided into two groups according to PS, and patient demographic data and postoperative outcomes were compared. Multiple regression analysis was performed to estimate the regression coefficient and 95% confidence intervals for 1-year QuickDASH after surgery with adjustment for age, PS, and malnutrition.

RESULTS

Possible sarcopenia was present in 10 patients (18.2%), and malnutrition in 24 patients (43.6%). Possible sarcopenia patients were older, had lower PNI, serum albumin, and both sides grip strength, and worse QuickDASH compared with non-PS patients. In multiple regression analysis, age, PS, and malnutrition were significant predictors of QuickDASH (standardized coefficient β, 0.35, 0.34, and 0.24; 95% confidence interval, 0.22-1.02, 3.52-16.49, and 0.50-10.78).

CONCLUSIONS

Possible sarcopenia with a healthy-side grip strength <18 kg and malnutrition with a PNI <50 were associated with worse 1-year QuickDASH after surgery in women DRF patients over 60 years.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic Ⅳ.

Nutritional factors and physical frailty: Highlighting the role of functional nutrients in the prevention and treatment

Physical frailty, an age-related decline in the physiological capacity and function of various organs, is associated with higher vulnerability to unfavorable health outcomes. The mechanisms proposed for physical frailty including increased inflammation and oxidative stress are closely related to nutritional status. In addition to traditional nutritional factors such as protein malnutrition and nutrient deficiencies, emerging evidence has focused on the role of functional nutrients including polyphenols, carotenoids, probiotics, prebiotics, omega-3 long-chain polyunsaturated fatty acids (n-3 PUFAs), β-hydroxy-β-methylbutyrate (HMB), coenzyme Q10 (CoQ10), and L-carnitine in modifying the risk of physical frailty syndrome. Although several clinical trials have suggested the beneficial effects of supplementation with polyphenols, HMB, and prebiotics on frailty indices, the current evidence is still not robust to support recommendations on the routine clinical use of such functional nutrients for the management of frailty. Similarly, the association between CoQ10 and frailty was mainly assessed in observational studies, and more randomized controlled trials are needed in this regard. A limited number of studies have reported the beneficial effect of L-carnitine supplementation on frailty indices. Since carnitine is mainly found in skeletal muscle and its measurement is thus challenging due to ethical constraints, it is necessary to examine the effect of different doses of L-carnitine on frailty and its indices in future studies. A large number of interventional studies evaluated the impact of n-3 PUFA supplementation on physical frailty in the elderly and many of them reported improved physical performance following supplementation, especially when combined with resistance training programs. Although promising findings from experimental and observational studies have been reported on functional nutrients, high-quality evidence from randomized controlled trials as well as detailed mechanistic studies are still required to affirm their role in the prevention and/or treatment of physical frailty. This review aims to describe the current state of research on functional nutrients that may modify the development or prognosis of frailty syndrome.

Interventions to prevent the onset of frailty in adults aged 60 and older (PRAE-Frail): a systematic review and network meta-analysis

PURPOSE

Frailty in older adults is associated with multiple adverse health outcomes, while evidence on its successful prevention has been scarce. Therefore, we analyzed the effectiveness of different interventions for the prevention of frailty onset.

METHODS

In this systematic review, eight databases were searched for randomized controlled trials of interventions in non-frail (i.e., robust or pre-frail) adults aged ≥ 60 years that assessed frailty incidence at follow-up. Additive component network meta-analysis (CNMA) was conducted to isolate the effect of different intervention types on the main outcome of frailty incidence, reporting relative risk (RR) with 95% confidence intervals (CI). The effect on gait speed was analyzed as an additional outcome using a classic network meta-analysis and the standardized mean difference (SMD) with 95% CI.

RESULTS

We screened 24,263 records and identified 11 eligible trials. Nine trials (842 participants, all categorized according to the physical phenotype) in pre-frail (seven RCTs) and robust/pre-frail (two RCTs) older adults were included in the CNMA. Physical exercise significantly reduced frailty incidence at follow-up (RR 0.26, 95% CI 0.08; 0.83), while this was not found for nutritional interventions (RR 1.16, 95% CI 0.33; 4.10). Interventions based on physical exercise also improved gait speed (SMD 1.55, 95% CI 1.16; 1.95). In addition, 22 eligible trial protocols without published results were identified.

CONCLUSION

Interventions based on physical exercise appear to be effective in preventing the onset of frailty in older adults. Although the available data are still limited, results from ongoing trials may add to the body of evidence in the foreseeable future.

Association between Drug Therapy and Risk of Incident Frailty: A Systematic Review

Medication is a potential factor influencing frailty. However, the relationship between pharmaceutical treatments and frailty remains unclear. Therefore, we conducted the present systematic review to summarize the association between drug therapy and the risk of incident frailty in older adults. We systematically searched the MEDLINE electronic database for articles indexed between January 1, 2000, and December 31, 2021, for randomized controlled trials (RCTs) and cohort studies reporting frailty changes associated with drug therapy. A total of six RCTs and 13 cohort studies involving 211,948 participants were identified, and their treatments were categorized into six medication classes: analgesics, cardiometabolic medication, chemotherapy, central nervous system (CNS)-active medication, hormonal therapy, and nutritional supplements. While the analysis revealed that only CNS-active medications were associated with an elevated risk of frailty, other medication classes also affected frailty; however, this is not conclusively attributable to a class-wide effect.

Metabolic dysfunction and the development of physical frailty: an aging war of attrition

The World Health Organization recently declared 2021-2030 the decade of healthy aging. Such emphasis on healthy aging requires an understanding of the biologic challenges aging populations face. Physical frailty is a syndrome of vulnerability that puts a subset of older adults at high risk for adverse health outcomes including functional and cognitive decline, falls, hospitalization, and mortality. The physiology driving physical frailty is complex with age-related biological changes, dysregulated stress response systems, chronic inflammatory pathway activation, and altered energy metabolism all likely contributing. Indeed, a series of recent studies suggests circulating metabolomic distinctions can be made between frail and non-frail older adults. For example, marked restrictions on glycolytic and mitochondrial energy production have been independently observed in frail older adults and collectively appear to yield a reliance on the highly fatigable ATP-phosphocreatine (PCr) energy system. Further, there is evidence that age-associated impairments in the primary ATP generating systems (glycolysis, TCA cycle, electron transport) yield cumulative deficits and fail to adequately support the ATP-PCr system. This in turn may acutely contribute to several major components of the physical frailty phenotype including muscular fatigue, weakness, slow walking speed and, over time, result in low physical activity and accelerate reductions in lean body mass. This review describes specific age-associated metabolic declines and how they can collectively lead to metabolic inflexibility, ATP-PCr reliance, and the development of physical frailty. Further investigation remains necessary to understand the etiology of age-associated metabolic deficits and develop targeted preventive strategies that maintain robust metabolic health in older adults.

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.

The intersection of frailty and metabolism

On average, aging is associated with unfavorable changes in cellular metabolism, which are the processes involved in the storage and expenditure of energy. However, metabolic dysregulation may not occur to the same extent in all older individuals as people age at different rates. Those who are aging rapidly are at increased risk of adverse health outcomes and are said to be "frail." Here, we explore the links between frailty and metabolism, including metabolic contributors and consequences of frailty. We examine how metabolic diseases may modify the degree of frailty in old age and suggest that frailty may predispose toward metabolic disease. Metabolic interventions that can mitigate the degree of frailty in people are reviewed. New treatment strategies developed in animal models that are poised for translation to humans are also considered. We suggest that maintaining a youthful metabolism into older age may be protective against frailty.

Can Leucine Supplementation Improve Frailty Index Scores?

Sarcopenia and frailty are important conditions that become increasingly prevalent with age. There is partial overlap between the two conditions, especially in terms of the physical aspects of the frailty phenotype: low grip strength, gait speed, and muscle mass. This study examined whether administration of the essential branched-chain amino acid leucine, besides improving sarcopenia, may reduce frailty assessed by frailty index (FI) in older institutionalized people living in nursing homes. We conducted a secondary analysis of a placebo-controlled, randomized, double-blind design study (ClinicalTrials.gov NCT03831399). The study included fifty males and females aged 65 and over who were living in nursing homes and did not have dementia. The participants were randomized to a parallel group intervention of 13 weeks' duration, with a daily intake of leucine (6 g/day) or placebo (lactose, 6 g/day). The outcome of this study was to evaluate whether there was a change in the level of a 95 item FI compared to the baseline and to compare the effect of the leucine group versus the placebo group. A significant inverse correlation was found between FI and performance of the activities of daily life, cognitive function, gait and balance, muscle function parameters, and nutritional status (p < 0.001 in all cases). There were no statistically significant differences in FI levels at baseline (placebo group FI 0.27 ± 0.08 and leucine group FI 0.27 ± 0.10) and at the 13 week follow-up (placebo group FI 0.28 ± 0.10 and leucine group FI 0.28 ± 0.09). There were also no significant differences between the leucine and placebo groups in the mean FI difference between baseline and follow-up (p = 0.316, Cohen's d: 0.04). This pilot study showed that a nutritional supplementation with leucine did not significantly modify the frailty index in older nursing home residents.

The effects of L-carnitine supplementation on inflammatory and anti-inflammatory markers in adults: a systematic review and dose-response meta-analysis

L-carnitine supplementation may be beneficial in improving inflammatory conditions and reducing the level of inflammatory cytokines. Therefore, according to the finding of randomized controlled trials (RCTs), the systematic review and meta-analysis aimed to investigate the effect of L-carnitine supplementation on inflammation in adults. To obtain acceptable articles up to October 2022, a thorough search was conducted in databases including PubMed, ISI Web of Science, the Cochrane Library, and Scopus. A random-effects model was used to estimate the weighted mean difference (WMD). We included the 48 RCTs (n = 3255) with 51 effect sizes in this study. L-carnitine supplementation had a significant effect on C-reactive protein (CRP) (p < 0.001), interleukin-6 (IL-6) (p = 0.001), tumor necrosis factor-α (TNF-α) (p = 0.002), malondialdehyde (MDA) (p = 0.001), total antioxidant capacity (TAC) (p = 0.029), alanine transaminase (ALT) (p < 0.001), and aspartate transaminase (AST) (p < 0.001) in intervention, compared to the placebo group. Subgroup analyses showed that L-carnitine supplementation had a lowering effect on CRP and TNF-α in trial duration ≥ 12 weeks in type 2 diabetes and BMI ≥ 25 kg/m2. L-carnitine supplementation reduced ALT levels in overweight and normal BMI subjects at any trial dose and trial duration ≥ 12 weeks and reduced AST levels in overweight subjects and trial dose ≥ 2 g/day. This meta-analysis revealed that L-carnitine supplementation effectively reduces the inflammatory state by increasing the level of TAC and decreasing the levels of CRP, IL-6, TNF-α and MDA in the serum.

Circulating inflammatory biomarker responses in intervention trials in frail and sarcopenic older adults: A systematic review and meta-analysis

Consistent with the inflammaging concept, cross-sectional associations have been established between inflammatory biomarkers, frailty and sarcopenia. Less certain is the value of inflammatory markers in monitoring potential anti-inflammatory effects of therapeutic interventions targeted at frailty and sarcopenia. The aims of this systematic review and meta-analysis are to determine if there is a measurable change in inflammatory or immune biomarkers in interventions that improve frailty or sarcopenia and 2. To determine if there are specific inflammatory biomarkers with greater sensitivity to change. In total, 3051 articles were scanned with 16, primarily exercise and nutrition interventions, included in the systematic review and 11 in the meta-analysis. At least one of C reactive protein (CRP), interleukin-6 (IL-6) or tumour necrosis factor alpha (TNF-α) was reduced in 10 of the 16 review studies but only 3/13 studies reported reductions in multiple markers. CRP, IL-6 and TNF-α were individually sensitive to change in 5/11, 3/12 and 5/12 studies respectively. In meta-analyses, there was a positive effect favouring intervention conditions for CRP (SMD = -0.28, p = 0.05) and IL-6 (SMD = -0.28, p = 0.05) but not TNF- α (SMD = -0.12, p = 0.48). There were specific issues with the quality of these studies which were not designed with an inflammatory marker as the primary outcome. In conclusion, interventions that improve frailty and sarcopenia can also reduce CRP, IL-6 and TNF-α but the literature lacks consistency. We are unable to conclude any one marker as being superior to others.

Potential of Food Protein-Derived Bioactive Peptides against Sarcopenia: A Comprehensive Review

Sarcopenia is an age-related progressive muscle disorder characterized by accelerated loss of muscle mass, strength, and function, which are important causes of physiological dysfunctions in the elderly. At present, the main alleviating method includes protein supplements to stimulate synthesis of muscle proteins. Food protein-derived peptides containing abundant branched-chain amino acids have a remarkable effect on the improvement of sarcopenia. Understanding the underlying molecular mechanism and clarifying the structure-activity relationship is essential for the mitigation of sarcopenia. This present review recaps the epidemiology, pathogenesis, diagnosis, and treatment of sarcopenia, which facilitates a comprehensive understanding of sarcopenia. Moreover, the latest research progress on food-derived antisarcopenic peptides is reviewed, including their antisarcopenic activity, molecular mechanism as well as structural characteristics. Food-derived bioactive peptides can indeed alleviate/mitigate sarcopenia. These antisarcopenic peptides play a pivotal role mainly by activating the PI3K/Akt/mTOR and MAPK pathways and inhibiting the ubiquitin-proteasome system and AMPK pathway, thus promoting the synthesis of muscle proteins and inhibiting their degradation. Antisarcopenic peptides alleviate sarcopenia via specific peptides, which may be absorbed into the circulation and exhibit their bioactivity in intact forms. The present review provides a theoretical reference for mitigation and prevention of sarcopenia by food protein-derived bioactive peptides.

Biomedical role of L-carnitine in several organ systems, cellular tissues, and COVID-19

Carnitine is a conditionally necessary vitamin that aids in energy creation and fatty acid metabolism. Its bioavailability is higher in vegetarians than in meat-eaters. Deficits in carnitine transporters occur because of genetic mutations or in conjunction with other illnesses. Carnitine shortage can arise in health issues and diseases-including hypoglycaemia, heart disease, starvation, cirrhosis, and ageing-because of abnormalities in carnitine control. The physiologically active form of L-carnitine supports immunological function in diabetic patients. Carnitine has been demonstrated to be effective in the treatment of Alzheimer's disease, several painful neuropathies, and other conditions. It has been used as a dietary supplement for the treatment of heart disease, and it also aids in the treatment of obesity and reduces blood glucose levels. Therefore, L-carnitine shows the potential to eliminate the influences of fatigue in COVID-19, and its consumption is recommended in future clinical trials to estimate its efficacy and safety. This review focused on carnitine and its effect on tissues, covering the biosynthesis, metabolism, bioavailability, biological actions, and its effects on various body systems and COVID-19.

Frailty as a predictor of poor outcomes among patients awaiting liver transplant: a systematic review and meta-analysis

Aim

This review sought to evaluate the significance of a functional assessment for liver transplant candidates, i.e., frailty, in the pre-transplant setting and its association with mortality and morbidities.

Background

Liver transplantation (LT) remains the treatment of choice for patients with end-stage liver disease. Due to the shortage of organs for LT, a careful selection of suitable recipients is essential. Frailty, a measure of physiologic reserve and increased vulnerability to stressors, was initially used in geriatrics and then introduced to the field of transplantation for better patient selection.

Methods

PubMed, Scopus, and Web of Science databases were reviewed up until January 2023. The search terms included: "frail*", "liver", and "transplant*". A Meta-analysis was conducted for the hazard ratios (HRs) obtained from the COX regression models. Fifty-five studies were included in this review; ten were included in the meta-analysis.

Results

The prevalence of frailty varied from 2.82% to 70.09% in the studies. Meta-analysis showed that overall frailty had a significant association with mortality (pooled adjusted HR [95%CI]: 2.66 [1.96-3.63]). Subgroup analyses revealed that both the Liver Frailty Index and Fried Frailty Index were significantly associated with mortality. Furthermore, these studies have demonstrated that this population's frailty is associated with ascites, hepatic encephalopathy, and esophageal varices.

Conclusion

According to emerging evidence, frailty is associated with increased morbidity and mortality of the patients on the LT waiting list. Further randomized trials are required to determine the efficacy and safety of variable interventions in the frail population.

Association between Immunosenescence, Mitochondrial Dysfunction and Frailty Syndrome in Older Adults

Aging is associated with changes in the immune system, increased inflammation and mitochondrial dysfunction. The relationship between these phenomena and the clinical phenotype of frailty is unclear. Here, we evaluated the immune phenotypes, T cell functions and mitochondrial functions of immune cells in frail and robust older subjects. We enrolled 20 frail subjects age- and gender-matched with 20 robust controls, and T cell phenotype, response to immune stimulation, cytokine production and immune cell mitochondrial function were assessed. Our results showed that numbers of CD4+ and CD8+ T cells were decreased in frail subjects, without impairment to their ratios. Memory and naïve T cells were not significantly affected by frailty, whereas the expression of CD28 but not that of ICOS was decreased in T cells from frail subjects. T cells from robust subjects produced more IL-17 after CD28 stimulation. Levels of serum cytokines were similar in frail subjects and controls. Mitochondrial bioenergetics and ATP levels were significantly lower in immune cells from frail subjects. In conclusion, we suggest that changes in T cell profiles are associated with aging rather than with frailty syndrome; however, changes in T cell response to immune stimuli and reduced mitochondrial activity in immune cells may be considered hallmarks of frailty.

Acetyl-L-carnitine Slows the Progression from Prefrailty to Frailty in Older Subjects: A Randomized Interventional Clinical Trial

BACKGROUND

Ageing is characterized by a gradual decline in body function, representing the clinical situation called "frailty". Prefrailty is the intermediate stage between frailty and robust condition. L-carnitine (LC) plays an important role in energy production from long-chain fatty acids in mitochondria, and its serum level is lower in prefrail and frail subjects.

OBJECTIVE

This study aims to evaluate the effect of Acetyl-L-carnitine (ALCAR) in pre-frail older patients.

METHODS

We scheduled 3 months of treatment and then 3 months of follow-up. A total of 92 subjects were selected from May, 2009 to July, 2017, in a randomized, observational, double-blind, placebo-controlled study. We scheduled 3 months of treatment and then 3 months of follow-up. ALCAR (oral 1.5 g/bis in die - BID) or placebo groups were used.

RESULTS

After the treatment, only the treated group displayed a decrease in C reactive protein (CRP) p < 0.001 and an increase in serum-free carnitine and acetylcarnitine (p < 0.05) in Mini-Mental state (MMSE) p < 0.0001 and 6-walking distance (p < 0.0001); ALCAR group vs. placebo group showed a decrease in HDL cholesterol and CRP (p < 0.01), an increase in MMSE score (p < 0.001) and in the 6-walking distance (p < 0.001).

CONCLUSIONS

ALCAR treatment delays the incidence and severity of onset of degenerative disorders of the elderly in prefrail subjects with improvement in memory and cognitive processes.

Fatigue in Covid-19 survivors: The potential impact of a nutritional supplement on muscle strength and function

BACKGROUND

Fatigue with reduced tolerance to exercise is a common persistent long-lasting feature amongst COVID-19 survivors. The assessment of muscle function in this category of patients is often neglected.

AIM

To evaluate the potential impact of a daily supplementation based on amino acids, minerals, vitamins, and plant extracts (Apportal®) on muscle function, body composition, laboratory parameters and self-rated health in a small group of COVID-19 survivors affected by fatigue.

METHODS

Thirty participants were enrolled among patients affected by physical fatigue during or after acute COVID-19 and admitted to the post-COVID-19 outpatient service at Fondazione Policlinico Gemelli in Rome between 1st March 2021 and 30th April 2021. All participants were evaluated at first visit (t0) and at control visit (t1), after taking a daily sachet of Apportal® for 28 days. Muscle function was analyzed using hand grip strength test, exhaustion strength time and the number of repetitions at one-minute chair stand test. Body composition was assessed with bioelectrical impedance analysis (BIA). Laboratory parameters, including standard blood biochemistry and ferritin levels, were evaluated at the first visit and during the control visit. A quick evaluation of self-rated health, before COVID-19, at t0 and t1, was obtained through a visual analogue scale (VAS).

RESULTS

Participants aged 60 years and older were 13 (43%). Females represented the 70% of the study sample. Participants hospitalized for COVID-19 with low-flow oxygen supplementation represented the 43.3% of the study sample while 3.3% received noninvasive ventilation (NIV) or invasive ventilation. Hand grip strength improved from 26.3 Kg to 28.9 Kg (p < 0.05) at t1 as compared to t0. The mean time of strength exhaustion increased from 31.7 s (sec) at t0 to 47.5 s at t1 (p < 0.05). Participants performed a higher number of repetitions (28.3 vs. 22.0; p < 0.05) during the one-minute chair stand test at t1 as compared to t0. A trend, although not significant, in reduction of ferritin levels was found after nutritional supplementation (94.4 vs. 84.3, respectively; p = 0.01). The self-rated health status increased by at least 13 points (t0, mean 57.6 ± 5.86; t1, mean 71.4 ± 6.73; p < 0.05).

CONCLUSIONS

After 28 days of nutritional supplementation with Apportal® in COVID-19 survivors affected by fatigue with reduced tolerance to exercise, we found a significant improvement in means of muscle strength and physical performance, associated with enhancement of self-rated health status between t0 and t1.

Frailty and cytokines in preclinical models: Comparisons with humans

Chronic low-grade elevations of blood-borne cytokines/chemokines in older age tend to associate with frailty in humans. This persistent inflammation is often called "inflammageing" and likely contributes to frailty progression. Preclinical models such as ageing and/or genetically modified mice offer a unique opportunity to mechanistically study how these inflammatory mediators affect frailty. In this review, we summarize and contrast evidence relating cytokines/chemokines to frailty in humans and in mouse models of frailty. In humans and mice, higher levels of the pro-inflammatory cytokine interleukin-6 regularly increased in proportion to the degree of frailty. Evidence linking other cytokines/chemokines to frailty in humans and mice is less certain. The chemokines CXCL-10 and monocyte chemoattractant protein-1 related to frailty across both species, but evidence is limited and inconsistent. Several other cytokines/chemokines, including tumour necrosis factor-α relate to frailty in humans or in mice, but evidence to date is species- and tissue-dependent. It is important for future studies to validate common mechanistic inflammatory biomarkers of frailty between humans and mice. Achieving this goal will accelerate the search for drugs to treat frailty.

Roles of nutrition in muscle health of community-dwelling older adults: evidence-based expert consensus from Asian Working Group for Sarcopenia

General muscle health declines with age, and in particular, sarcopenia-defined as progressive loss of muscle mass and strength/physical performance-is a growing issue in Asia with a rising population of community-dwelling older adults. Several guidelines have addressed early identification of sarcopenia and management, and although nutrition is central to treatment of sarcopenia, there are currently few guidelines that have examined this specifically in the Asian population. Therefore, the Asian Working Group for Sarcopenia established a special interest group (SIG) comprising seven experts across Asia and one from Australia, to develop an evidence-based expert consensus. A systematic literature search was conducted using MEDLINE on the topic of muscle health, from 2016 (inclusive) to July 2021, in Asia or with relevance to healthy, Asian community-dwelling older adults (≥60 years old). Several key topics were identified: (1) nutritional status: malnutrition and screening; (2) diet and dietary factors; (3) nutritional supplementation; (4) lifestyle interventions plus nutrition; and (5) outcomes and assessment. Clinical questions were developed around these topics, leading to 14 consensus statements. Consensus was achieved using the modified Delphi method with two rounds of voting. Moreover, the consensus addressed the impacts of COVID-19 on nutrition, muscle health, and sarcopenia in Asia. These statements encompass clinical expertise and knowledge across Asia and are aligned with findings in the current literature, to provide a practical framework for addressing muscle health in the community, with the overall aim to encourage and facilitate broader access to equitable care for this target population.

L-Carnitine Combined with Leucine Supplementation Does Not Improve the Effectiveness of Progressive Resistance Training in Healthy Aged Women

OBJECTIVES

To evaluate the effect of L-carnitine (LC) in combination with leucine supplementation on muscle strength and muscle hypertrophy in aged women participating in a resistance exercise training (RET) program.

DESIGN/SETTING/PARTICIPANTS

Thirty-seven out of sixty (38.3% dropout) healthy women aged 60-75 years (mean 67.6 ± 0.7 years) completed the intervention in one of three groups. One of the supplemented groups received 1 g of L-carnitine-L-tartrate in combination with 3 g of L-leucine per day (LC+L group; n = 12), and the second supplemented group received 4 g of L-leucine per day (L group; n = 13). The control group (CON group; n = 12) received no supplementation.

INTERVENTION

All three groups completed the same RET protocol involving exercise sessions twice per week for 24 weeks.

MEASUREMENTS

Before and after the experiment, participants performed isometric and isokinetic muscle strength testing on the Biodex dynamometer. The cross-sectional areas of the major knee extensors and total thigh muscles were assessed using magnetic resonance imaging. Fasting serum levels of insulin-like growth factor-1 (IGF-1), myostatin and decorin, and plasma levels of total carnitine (TC) and trimethylamine-N-oxide (TMAO) levels were measured.

RESULTS

The 24-week RET significantly increased muscle strength and muscle volume, but the group and time interactions were not significant for the muscle variables analyzed. Plasma total carnitine increased only in the LC+L group (p = 0.009). LC supplementation also caused a significant increase in plasma TMAO, which was higher after the intervention in the LC+L group than in the L (p < 0.001), and CON (p = 0.005) groups. The intervention did not change plasma TMAO concentration in the L (p = 0.959) and CON (p = 0.866) groups. After the intervention serum decorin level was higher than before in both supplemented groups combined (p = 0.012), still not significantly different to post intervention CON (p = 0.231). No changes in serum IGF-1 and myostatin concentrations and no links between the changes in blood markers and muscle function or muscle volume were observed.

CONCLUSIONS

LC combined with leucine or leucine alone does not appear to improve the effectiveness of RET.

Current Clinical Implications of Frailty and Sarcopenia in Vascular Surgery: A Comprehensive Review of the Literature and Consideration of Perioperative Management

Frailty is a well-known geriatric syndrome of impaired physiological reserve and increased vulnerability to stressors. Sarcopenia is also used as a parameter of physical impairment characterized by muscle weakness. As population aging has become more prominent in recent years, both modalities are now regarded as clinically important prognostic tools defined by multidimensional factors that may affect clinical outcomes in various clinical settings. A preoperative surgical risk analysis is mandatory to predict clinical and surgical outcomes in all surgical practices, particularly in high-risk surgical patients. In vascular surgical settings, frailty and sarcopenia have been accepted as useful prognostic tools to evaluate patient characteristics before surgery, as these may predict perioperative clinical and surgical outcomes. Although minimally invasive surgical approaches, such as endovascular therapy, and hybrid approaches have been universally developed, achieving good vascular surgical outcomes for high-risk cohorts remains to be challenge due to the increasing prevalence of elderly patients and multiple preoperative co-morbidities in addition to frailty and sarcopenia. Therefore, to further improve clinical and surgical outcomes, these preoperative geriatric prognostic factors will be of great importance and interest in vascular surgical settings for both physicians and surgeons.

Clinical Effects of L-Carnitine Supplementation on Physical Performance in Healthy Subjects, the Key to Success in Rehabilitation: A Systematic Review and Meta-Analysis from the Rehabilitation Point of View

L-carnitine supplementation improves body strength, sports endurance and exercise capacity, as well as delaying the onset of fatigue. The aim of this study was to identify the correct dosage of supplementation to obtain improvements in physical performance and evaluate the changes related to L-carnitine supplementation in specific metabolic parameters, such as serum lactate, VO2, serum total and free carnitine at rest and after physical activities, in healthy subjects. The search was conducted on PubMed, EMBASE, Cochrane Library, Scopus and Web of Science and identified 6404 articles with the keywords: "carnitine" AND "exercises" OR "rehabilitation" OR "physical functional performance" OR "physical activity" OR "sports" OR "health" OR "healthy". A total of 30 publications met the inclusion criteria and were included in the systematic review. The meta-analysis did not show any significant differences in serum lactate values at rest and after exercise in healthy subjects who took L-carnitine supplementation (p > 0.05). On the contrary, L-carnitine administration significantly changed maximal oxygen consumption (VO2) at rest (p < 0.005), serum free and total carnitine at rest and after exercise (p < 0.001). The dosage of supplementation that obtained a significant change in serum total carnitine was 2 g/dL for 4 weeks at rest, 1 g/dL for 3 weeks after exercise, and in serum free carnitine was 2 g/dL for 3 weeks and 2 g/dL for 4 weeks at rest. Based on our study, serum total and free carnitine at rest and after exercise, and VO2 at rest could be used to clinically follow individuals during physical activity and rehabilitation programs. Moreover, the supplementation should have a correct dosage to have maximum effect. Other robust trials are needed to find the best dosage to obtain positive results in metabolic parameters and in physical performance.

Frailty Pathogenesis, Assessment, and Management in Older Adults With COVID-19

The 2019 coronavirus disease (COVID-19) is a highly contagious and deadly disease. The elderly people are often accompanied by chronic inflammation and immunodeficiency, showing a frail state. The strength, endurance, and physiological function of the elderly are significantly decreased, and the ability to deal with stress response is weakened. They are the high-risk group that suffering from COVID-19, and rapidly developing to critical illness. Several recent studies suggest that the incidence rate of COVID-19 in elderly patients with frailty is high. Early assessment, detection, and effective intervention of frailty in COVID-19 patients are conducive to significantly improve the quality of life and improve prognosis. However, there are insufficient understanding and standards for the current evaluation methods, pathogenesis and intervention measures for COVID-19 combined with frailty. This study reviews the progress of the research on the potential pathogenesis, evaluation methods and intervention measures of the elderly COVID-19 patients with frailty, which provides a reference for scientific and reasonable comprehensive diagnosis and treatment in clinical.

L-carnitine extenuates endocrine disruption, inflammatory burst and oxidative stress in carbendazim-challenged male rats via upregulation of testicular StAR and FABP9, and downregulation of P38-MAPK pathways

We have addressed in the current study the potential of L-carnitine (LC) to extenuate the reproductive toxic insults of carbendazim (CBZ) in male rats, and the molecular mechanisms whereby carnitine would modify the spermatogenic and steroidogenic derangements invoked by the endocrine disruptor. Herein, animals received daily doses of carbendazim (100 mg/kg) by gavage for 8 weeks. Another CBZ-challenged group was co-supplemented with LC (500 mg/kg, IP) twice weekly for 8 weeks. Sperm quantity and quality (morphology, motility and viability), serum testosterone and gonadotropins, and thyroid hormone levels were assessed. Serum tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and interleukin-10 (IL-10) concentrations were determined by ELISA. Oxidant/antioxidant status in rat testis was investigated via measuring testicular contents of malondialdehyde (MDA) and reduced glutathione (GSH), as well as the activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Immunohistochemical localizations of the junctional protein; occludin, and inflammatory markers; inducible nitric oxide synthase (iNOS) and nuclear factor kappa beta (NF-κB) were further analyzed. A host of transduction genes that regulate spermatogenic and steroidogenic pathways, and their encoded proteins namely, Steroidogenic Acute Regulatory Protein (StAR), Fatty acid binding protein 9 (FABP9) and P38-mitogen activated protein kinase (P38-MAPK) were assessed by real time quantitative (RT-qPCR) and Western blot. LC improved rat spermiogram, testicular histological alterations and endocrine perturbances, and modulated genes' expressions and their respective proteins. In conclusion, LC effects appear to reside for the most part on its endocrine-preserving, anti-oxidant and anti-inflammatory properties through a myriad of interlaced signal transductions that ultimately recapitulated its beneficial effects on spermatogenesis and steroidogenesis.

Significance of Levocarnitine Treatment in Dialysis Patients

Carnitine is a naturally occurring amino acid derivative that is involved in the transport of long-chain fatty acids to the mitochondrial matrix. There, these substrates undergo β-oxidation, producing energy. The major sources of carnitine are dietary intake, although carnitine is also endogenously synthesized in the liver and kidney. However, in patients on dialysis, serum carnitine levels progressively fall due to restricted dietary intake and deprivation of endogenous synthesis in the kidney. Furthermore, serum-free carnitine is removed by hemodialysis treatment because the molecular weight of carnitine is small (161 Da) and its protein binding rates are very low. Therefore, the dialysis procedure is a major cause of carnitine deficiency in patients undergoing hemodialysis. This deficiency may contribute to several clinical disorders in such patients. Symptoms of dialysis-related carnitine deficiency include erythropoiesis-stimulating agent-resistant anemia, myopathy, muscle weakness, and intradialytic muscle cramps and hypotension. However, levocarnitine administration might replenish the free carnitine and help to increase carnitine levels in muscle. This article reviews the previous research into levocarnitine therapy in patients on maintenance dialysis for the treatment of renal anemia, cardiac dysfunction, dyslipidemia, and muscle and dialytic symptoms, and it examines the efficacy of the therapeutic approach and related issues.

Exploring Clinically Meaningful Changes for the Frailty Index in a Longitudinal Cohort of Hospitalized Older Patients

BACKGROUND

Clinically meaningful change (CMC) for frailty index (FI) scores is little studied. We estimated the CMC by associating changes in FI scores with changes in the Clinical Frailty Scale (CFS) in hospitalized patients.

METHODS

The Serious Outcomes Surveillance Network of the Canadian Immunization Research Network enrolled older adults (65+ years) admitted to hospital with acute respiratory illness (mean age = 79.6 ± 8.4 years; 52.7% female). Patients were assigned CFS and 39-item FI scores in-person at admission and via telephone at 1-month postdischarge. Baseline frailty state was assessed at admission using health status 2 weeks before admission. We classified those whose CFS scores remained unchanged (n = 1,534) or increased (n = 4,390) from baseline to hospital admission, and whose CFS scores remained unchanged (n = 1,565) or decreased (n = 2,546) from admission to postdischarge. For each group, the CMC was represented as the FI score change value that best predicted one level CFS change, having the largest Youden J value in comparison to no change.

RESULTS

From baseline to admission, 74.1% increased CFS by ≥1 level. From admission to postdischarge, 61.9% decreased CFS by ≥1 levels. A change in FI score of 0.03 best predicted both one-level CFS increase (sensitivity = 70%; specificity = 69%) and decrease (sensitivity = 66%; specificity = 61%) in comparison to no change. Of those who changed CFS by ≥1 levels, 70.9% (baseline to admission) and 72.4% (admission to postdischarge) changed their FI score by at least 0.03.

CONCLUSIONS

A clinically meaningful change of 0.03 in the frailty index score holds promise as a benchmark for assessing the meaningfulness of frailty interventions.

Allicin Reversed the Process of Frailty in Aging Male Fischer 344 Rats With Osteoporosis

The research and development of pharmaceutical intervention is insufficient for the frail older adults, especially in preclinical stage for the frail individuals with osteoporosis. Garlic exerts an antiosteoporotic effect and its vital component allicin could protect organisms against aging. The present study aimed to investigate the effect of long-term intragastric administration of allicin (low dose of 4 mg·kg⁻¹·d⁻¹; middle dose of 8 mg·kg⁻¹·d⁻¹; high dose of 16 mg·kg⁻¹·d⁻¹) on frailty with osteoporosis in aging male Fischer 344 rats. Frailty was assessed with a 27-item frailty index based on quantifying health-related deficits in adult male rats varied from 13 to 21 months and in control rats from 6 to 9 months. Osteoporosis was appraised by bone mineral density detected by dual-energy X-ray absorptiometry, biomechanical properties measured by a three-point bending test, and bone metabolic analysis using ELISA. Allicin could attenuate frailty index scores by reducing the accumulation of health deficits in aging male Fischer 344 rats. Meanwhile, allicin could protect against senile osteoporosis, and the underlying mechanism may involve in increasing low bone turnover through elevation of both bone formation and bone resorption, and subsequently lead to increase of bone mineral density, contributing to reversing deleterious bone biomechanical features associated with aging. The present study reveals firstly that long-term oral administration with allicin attenuated frailty with osteoporosis during the process of aging, which provides a preclinical evidence for intervention of frailty.

Management of Frailty: A Systematic Review and Network Meta-analysis of Randomized Controlled Trials

OBJECTIVE

To analyze and determine the comparative effectiveness of interventions targeting frailty prevention or treatment on frailty as a primary outcome and quality of life, cognition, depression, and adverse events as secondary outcomes.

DESIGN

Systematic review and network meta-analysis (NMA).

METHODS

Data sources-Relevant randomized controlled trials (RCTs) were identified by a systematic search of several electronic databases including MEDLINE, EMBASE, CINAHL, and AMED. Duplicate title and abstract and full-text screening, data extraction, and risk of bias assessment were performed. Data extraction-All RCTs examining frailty interventions aimed to decrease frailty were included. Comparators were standard care, placebo, or another intervention. Data synthesis-We performed both standard pairwise meta-analysis and Bayesian NMA. Dichotomous outcome data were pooled using the odds ratio effect size, whereas continuous outcome data were pooled using the standardized mean difference (SMD) effect size. Interventions were ranked using the surface under the cumulative ranking curve (SUCRA) for each outcome. The quality of evidence was evaluated using the GRADE approach.

RESULTS

A total of 66 RCTs were included after screening of 7090 citations and 749 full-text articles. NMA of frailty outcome (including 21 RCTs, 5262 participants, and 8 interventions) suggested that the physical activity intervention, when compared to placebo and standard care, was associated with reductions in frailty (SMD -0.92, 95% confidence interval -1.55, -0.29). According to SUCRA, physical activity intervention and physical activity plus nutritional supplementation were probably the most effective intervention (100% and 71% likelihood, respectively) to reduce frailty. Physical activity was probably the most effective or the second most effective interventions for all included outcomes.

CONCLUSION AND IMPLICATIONS

Physical activity is one of the most effective frailty interventions. The quality of evidence of the current review is low and very low. More robust RCTs are needed to increase the confidence of our NMA results and the quality of evidence.

Intake of Seven Essential Amino Acids Improves Cognitive Function and Psychological and Social Function in Middle-Aged and Older Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

Background: To delay the onset of dementia, it is important for healthy adults to take preventive actions before the cognitive function clearly declines. Protein malnutrition is a potential risk factor for senile dementia, although the precise link between protein/amino acid nutrition and cognitive function is unknown. The purpose of this study was to examine the effect of the ingestion of seven selected essential amino acids as a granular powder, namely, leucine, phenylalanine, and lysine supplemented with isoleucine, histidine, valine, and tryptophan on cognitive and psychosocial functions in healthy adults. Methods: A double-blind, randomized, placebo-controlled trial was conducted. A total of 105 participants aged 55 years or older were randomly assigned to one of three groups: daily ingestion of 3 g (3gIG) or 6 g (6gIG) of the selected amino acids or daily ingestion of a placebo (PCG). Each group ingested the test powder for 12 weeks. As the main outcome, cognitive function was assessed before and after ingestion by a cognitive test battery. Psychosocial functions were also examined. Results: The numbers of participants excluding dropouts were 35 in PCG and 3gIG and 33 in 6gIG. Analysis of covariance revealed that the 6gIG showed significantly improved cognitive function (Trail Making Test B), social interaction and psychological health scores after ingestion compared to the PCG (multiplicity adjusted p < 0.05). Conclusions: Current findings suggested that ingestion of the seven essential amino acids led to improved attention and cognitive flexibility and psychosocial functioning, which is expected to prevent cognitive decline. Clinical Trial Registration: University Hospital Medical Information Network Clinical Trial Registry (URL: https://upload.umin.ac.jp/cgi-open-bin/ctr/ctr_view.cgi?recptno=R000037779, Identifier: UMIN000033174).

Circulating plasma metabolites and risk of rheumatoid arthritis in the Nurses' Health Study

OBJECTIVES

RA develops slowly over years. We tested for metabolic changes prior to RA onset using a large non-targeted metabolomics platform to identify novel pathways and advance understanding of RA development.

METHODS

Two hundred and fifty-four incident RA cases with plasma samples drawn pre-RA onset in the Nurses' Health Study (NHS) cohorts were matched 1:2 to 501 controls on age, race, menopause/post-menopausal hormone use and blood collection features. Relative abundances of 360 unique, known metabolites were measured. Conditional logistic regression analyses assessed associations between metabolites and incidence of RA, adjusted for age, smoking and BMI, accounting for multiple comparisons. Subgroup analyses investigated seropositive (sero+) RA and RA within 5 years of sample collection. Significant metabolites were then tested in a female military pre-RA case-control study (n = 290).

RESULTS

In the NHS, metabolites associated with RA and sero+RA in multivariable models included 4-acetamidobutanoate (odds ratio (OR) = 0.80/S.d., 95% CI: 0.66, 0.95), N-acetylputrescine (OR = 0.82, 95% CI: 0.69, 0.96), C5 carnitine (OR = 0.84, 95% CI: 0.71, 0.99) and C5:1 carnitine (OR = 0.81, 95% CI: 0.68, 0.95). These were involved primarily in polyamine and leucine, isoleucine and valine metabolism. Several metabolites associated with sero+RA within 5 years of diagnosis were replicated in the independent military cohort: C5 carnitine (OR = 0.55, 95% CI: 0.33, 0.92), C5:1 carnitine (OR = 0.62, 95% CI: 0.39, 0.99) and C3 carnitine (OR = 0.57, 95% CI: 0.36, 0.91).

CONCLUSION

Several metabolites were inversely associated with incidence of RA among women. Three short-chain acylcarnitines replicated in a smaller dataset and may reflect inflammation in the 5-year period prior to sero+RA diagnosis.

The effects of L-carnitine supplementation on indicators of inflammation and oxidative stress: a systematic review and meta-analysis of randomized controlled trials

Objective

Several trials investigated the efficacy of L-carnitine administration on markers of inflammation and indicators of oxidative stress; however, their findings are controversial. The aim of this study was to conduct a comprehensive meta-analysis and a critical review, which would analyze all randomized controlled trials (RCTs) in order to determine the effects of L-carnitine supplementation on inflammatory markers and oxidative stress.

Methods

An electronic search was performed using Scopus, Cochrane Library, PubMed, Google scholar and Web of Science databases on publications from 1990 up to May 2020. Human RCTs conducted in healthy subjects or participants with certain disorders which investigating the efficacy of L-carnitine supplementation compared to control (placebo, usual treatment or no intervention) on inflammation and oxidative markers were included. Data were pooled applying a random-effects model and as the overall effect size, weighted mean difference (WMD) was presented. Between heterogeneity among studies was computed using Cochran's Q test and I-square (I²). Quality of studies assessed using the Jadad scale. Dose-response analysis was measured using meta-regression. The funnel plot, as well as the Egger's regression test was applied to determine the publication bias.

Results

44 trials (reported 49 effect sizes for different outcomes of interest) met the inclusion criteria for this meta-analysis. According to the findings, L-carnitine supplementation resulted in a significant reduction in C-reactive protein (CRP) (WMD: -0.10; 95% CI: -0.14, -0.06), interleukin 6 (IL-6) (WMD: -1.87; 95% CI: -2.80, -0.95), tumor necrosis factor-α (TNF-α) levels (WMD: -1.43; 95% CI: -2.03, -0.84), and malondialdehyde (MDA) (WMD: -0.47; 95% CI: -0.76, -0.18) levels, while there was a significant increase in superoxide dismutase (SOD) (WMD: 2.14; 95% CI: 1.02, 3.25). However, no significant effects of L-carnitine on glutathione peroxidase (GPx) (WMD: 0.02; 95% CI: -0.01, 0.05) and total antioxidant capacity (TAC) (WMD: 0.14; 95% CI: -0.05, 0.33) were found.

Conclusions

L-carnitine supplementation was associated with lowering of CRP, IL-6, TNF-α, and MDA, and increasing SOD levels, but did not affect other inflammatory and oxidative stress biomarkers.

Frailty Intervention through Nutrition Education and Exercise (FINE). A Health Promotion Intervention to Prevent Frailty and Improve Frailty Status among Pre-Frail Elderly-A Study Protocol of a Cluster Randomized Controlled Trial

The ageing process has been associated with various geriatric issues including frailty. Without early prevention, frailty may cause multiple adverse outcomes. However, it potentially may be reversed with appropriate interventions. The aim of the study is to assess the effectiveness of nutritional education and exercise intervention to prevent frailty among the elderly. A 3-month, single-blind, two-armed, cluster randomized controlled trial of the frailty intervention program among Malaysian pre-frail elderly will be conducted. A minimum of total 60 eligible respondents from 8 clusters (flats) of Program Perumahan Rakyat (PPR) flats will be recruited and randomized to the intervention and control arm. The intervention group will receive a nutritional education and a low to moderate multi-component exercise program. To date, this is the first intervention study that specifically targets both the degree of frailty and an improvement in the outcomes of frailty using both nutritional education and exercise interventions among Malaysian pre-frail elderly. If the study is shown to be effective, there are major potential benefits to older population in terms of preventing transition to frailty. The findings from this trial will potentially provide valuable evidence and serve as a model for similar future interventions designed for elderly Malaysians in the community.

Nutritional Intervention as a Preventive Approach for Cognitive-Related Outcomes in Cognitively Healthy Older Adults: A Systematic Review

The link diet-cognitive function/dementia has been largely investigated in observational studies; however, there was a lack of evidence from randomized clinical trials (RCTs) on the prevention of late-life cognitive disorders though dietary intervention in cognitively healthy older adults. In the present article, we systematically reviewed RCTs published in the last four years (2014-2017) exploring nutritional intervention efficacy in preventing the onset of late-life cognitive disorders and dementia in cognitively healthy subjects aged 60 years and older using different levels of investigation (i.e., dietary pattern changes/medical food/nutraceutical supplementation/multidomain approach and dietary macro- and micronutrient approaches) as well as possible underlying mechanisms of nutritional prevention. From the 35 included RCTs, there was moderate evidence that intervention through dietary pattern changes, medical food/nutraceutical supplementation, and multidomain approach improved specific cognitive domains or cognitive-related blood biomarkers. There was high evidence that protein supplementation improved specific cognitive domains or functional status in prefrail older adults without effect on cognitive function. For fatty acid supplementation, mainly long-chain polyunsaturated fatty acids, there was emerging evidence suggesting an impact of this approach in improving specific cognitive domains, magnetic resonance imaging (MRI) findings, and/or cognitive-related biomarkers also in selected subgroups of older subjects, although some results were conflicting. There was convincing evidence of an impact of non-flavonoid polyphenol and flavonoid supplementations in improving specific cognitive domains and/or MRI findings. Finally, there was only low evidence suggesting efficacy of intervention with homocysteine-related and antioxidant vitamins in improving cognitive functions, dementia incidence, or cognitive-related biomarkers in cognitively healthy older subjects.

Frailty biomarkers in humans and rodents: Current approaches and future advances

Even though they would have great benefit across research and clinical fields, currently there are no accepted biomarkers of frailty. Cross-sectional studies in humans have identified promising candidates including inflammatory markers such as IL-6, immune markers such as WBC count, clinical markers such as albumin, endocrine markers such as vitamin D, oxidative stress markers such as isoprostanes, proteins such as BDNF and epigenetic markers such as DNA methylation, but there are limitations to the current state of the research. Future approaches to the identification of frailty biomarkers should include longitudinal studies, studies using animal models of frailty, studies incorporating novel biomarkers combined into composite panels, and studies investigating sex differences and potential overlap between markers of biological age and frailty.

The effect of L-carnitine on inflammatory mediators: a systematic review and meta-analysis of randomized clinical trials

AIM AND BACKGROUND

Reducing inflammation by nutritional supplements may help to reduce the risk of many chronic diseases. Our aim in this meta-analysis was to determine the effect of L-carnitine on inflammatory mediators including C-reactive protein (CRP), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6).

METHODS

Our systematic search to find relevant randomized clinical trials (RCTs) was performed up to October 2018 using ISI Web of Science, Google Scholar, PubMed/Medline, and SCOPUS. In this meta-analysis, the weighted mean differences (WMD) with standard errors (SE) were used to pool the data. WMD was calculated by subtracting change-from-baseline mean values in the control group from change-from-baseline mean values in the intervention group in each study. To identify heterogeneity among studies, the I² statistic was employed. The protocol was registered with PROSPERO (No. CRD42019116695).

RESULTS

Thirteen articles were included in our systematic review and meta-analysis. The results of the meta-analysis indicated that L-carnitine supplementation was significantly associated with lower levels of CRP in comparison to controls (WMD = -1.23 mg/L; 95% CI: -1.73, -0.72 mg/dL; P < 0.0001). Also, a slight but statistically significant decrease was observed in IL-6 and TNF-α levels (WMD = -0.85 pg/dL; 95% CI: -1.38, -0.32 pg/dL; P = 0.002 and WMD = -0.37 pg/dL; 95% CI: -0.68, -0.06 pg/dL; P = 0.018, respectively).

CONCLUSION

Our results indicate that L-carnitine reduced inflammatory mediators, especially in studies with a duration of more than 12 weeks. Further studies with different doses and intervention durations and separately in men and women are necessary.

Dietary Factors Associated with Frailty in Old Adults: A Review of Nutritional Interventions to Prevent Frailty Development

Frailty syndrome is a medical condition that is characterised by a functional decline, usually from 65 years old on, and creates the need for assistance to perform daily living activities. As the population ages, the need for specialised geriatric care will increase immensely, and consequently, the need for specialised services for the care of these people will increase accordingly. From a nutritional point of view, to control or balance the nutritional status of residents will be essential in order to prevent sarcopenia and, consequently, frailty development. In this line, previous studies have highlighted the association among low energy intake, inadequate intake of protein and vitamin D, and an increased risk of frailty development. However, there is a lack of intervention studies on frail patients, especially in the realm of quality clinical trials. The few studies performed to date seem to indicate that there is a protective role of protein supplementation against frailty syndrome. In this regard, it is tempting to suggest daily 30 g protein supplements to prevent frailty. However, it is well established that excess protein can also be harmful; therefore, specific individual characteristics should be considered before prescribing these supplements. On the other hand, the relevance of other nutritional interventions, such as vitamin D, omega-3, and medium-chain triglycerides, is much more scarce in the literature. Therefore, we encourage the development of new clinical trials to carry out effective therapies to prevent frailty development.

Efficacy of L-carnitine supplementation for improving lean body mass and physical function in patients on hemodialysis: a randomized controlled trial

BACKGROUND

Carnitine deficiency is common in patients on hemodialysis. However, the efficacy of L-carnitine supplementation for improving lean body mass (LBM) and physical function has not yet been evaluated.

METHODS

In this multicenter, prospective, parallel, randomized, controlled trial, 91 patients on hemodialysis who developed carnitine deficiency were randomly assigned to receive injections of 1,000 mg L-carnitine 3 times per week after each hemodialysis session (L-carnitine group) or no injections (control group) with monitoring for 12 months.

RESULTS

The data for 84 of the 91 patients were available for analysis (L-carnitine group, n = 42; control group, n = 42). Dry weight and body mass index did not significantly change in the L-carnitine group, but significantly decreased in the control group. Arm muscle area (AMA) did not change significantly in the L-carnitine group but decreased significantly in the control group; the difference in mean AMA between the groups was 6.22% (95% confidence interval [CI] 1.90-10.5; P = 0.037). Hand grip strength did not change significantly in the L-carnitine group, but decreased significantly in the control group. The difference in change in hand grip strength between the groups was 4.27% (95% CI 0.42-8.12; P = 0.030). Furthermore, LBM did not change significantly in the L-carnitine group but decreased significantly in the control group; the difference in mean LBM between the groups was 2.92 % (95% CI 1.28-4.61; P = 0.0007).

CONCLUSIONS

L-carnitine supplementation is useful in patients who develop carnitine deficiency on hemodialysis because it maintains physical function and LBM.

Mitochondrial function is impaired in the skeletal muscle of pre-frail elderly

Aging is accompanied by a gradual decline in both muscle mass and strength over time, which can eventually lead to pathologies, such as frailty and sarcopenia. While these two conditions are well characterized, further investigation of the early biological signs present in pre-frail elderly is still needed to help identify strategies for preventative therapeutic intervention. The goal of the present clinical study was to evaluate the level of mitochondrial (dys)function in a well-defined population of pre-frail elderly (>60 years of age). Pre-frail elderly were compared with an age-matched population of active elderly. Muscle mitochondrial function was assessed in vivo using phosphorus magnetic resonance spectroscopy (³¹P-MRS) and a comprehensive set of biological biomarkers were measured ex vivo in vastus lateralis muscle biopsies. In pre-frail subjects, phosphocreatine recovery was impaired and mitochondrial respiratory complex protein and activity levels were significantly lower when compared with active elderly. Analysis of microarray data showed that mitochondrial genes were also significantly down-regulated in muscle of pre-frail compared to active elderly. These results show that mitochondrial impairment is a hallmark of pre-frailty development and the onset of decline in muscle function in the elderly.

l-Carnitine Supplementation in Recovery after Exercise

Given its pivotal role in fatty acid oxidation and energy metabolism, l-carnitine has been investigated as ergogenic aid for enhancing exercise capacity in the healthy athletic population. Early research indicates its beneficial effects on acute physical performance, such as increased maximum oxygen consumption and higher power output. Later studies point to the positive impact of dietary supplementation with l-carnitine on the recovery process after exercise. It is demonstrated that l-carnitine alleviates muscle injury and reduces markers of cellular damage and free radical formation accompanied by attenuation of muscle soreness. The supplementation-based increase in serum and muscle l-carnitine contents is suggested to enhance blood flow and oxygen supply to the muscle tissue via improved endothelial function thereby reducing hypoxia-induced cellular and biochemical disruptions. Studies in older adults further showed that l-carnitine intake can lead to increased muscle mass accompanied by a decrease in body weight and reduced physical and mental fatigue. Based on current animal studies, a role of l-carnitine in the prevention of age-associated muscle protein degradation and regulation of mitochondrial homeostasis is suggested.

Home-based health promotion for older people with mild frailty: the HomeHealth intervention development and feasibility RCT

BACKGROUND

Mild frailty or pre-frailty is common and yet is potentially reversible. Preventing progression to worsening frailty may benefit individuals and lower health/social care costs. However, we know little about effective approaches to preventing frailty progression.

OBJECTIVES

(1) To develop an evidence- and theory-based home-based health promotion intervention for older people with mild frailty. (2) To assess feasibility, costs and acceptability of (i) the intervention and (ii) a full-scale clinical effectiveness and cost-effectiveness randomised controlled trial (RCT).

DESIGN

Evidence reviews, qualitative studies, intervention development and a feasibility RCT with process evaluation.

INTERVENTION DEVELOPMENT

Two systematic reviews (including systematic searches of 14 databases and registries, 1990-2016 and 1980-2014), a state-of-the-art review (from inception to 2015) and policy review identified effective components for our intervention. We collected data on health priorities and potential intervention components from semistructured interviews and focus groups with older people (aged 65-94 years) (n = 44), carers (n = 12) and health/social care professionals (n = 27). These data, and our evidence reviews, fed into development of the 'HomeHealth' intervention in collaboration with older people and multidisciplinary stakeholders. 'HomeHealth' comprised 3-6 sessions with a support worker trained in behaviour change techniques, communication skills, exercise, nutrition and mood. Participants addressed self-directed independence and well-being goals, supported through education, skills training, enabling individuals to overcome barriers, providing feedback, maximising motivation and promoting habit formation.

FEASIBILITY RCT

Single-blind RCT, individually randomised to 'HomeHealth' or treatment as usual (TAU).

SETTING

Community settings in London and Hertfordshire, UK.

PARTICIPANTS

A total of 51 community-dwelling adults aged ≥ 65 years with mild frailty.

MAIN OUTCOME MEASURES

Feasibility - recruitment, retention, acceptability and intervention costs. Clinical and health economic outcome data at 6 months included functioning, frailty status, well-being, psychological distress, quality of life, capability and NHS and societal service utilisation/costs.

RESULTS

We successfully recruited to target, with good 6-month retention (94%). Trial procedures were acceptable with minimal missing data. Individual randomisation was feasible. The intervention was acceptable, with good fidelity and modest delivery costs (£307 per patient). A total of 96% of participants identified at least one goal, which were mostly exercise related (73%). We found significantly better functioning (Barthel Index +1.68; p = 0.004), better grip strength (+6.48 kg; p = 0.02), reduced psychological distress (12-item General Health Questionnaire -3.92; p = 0.01) and increased capability-adjusted life-years [+0.017; 95% confidence interval (CI) 0.001 to 0.031] at 6 months in the intervention arm than the TAU arm, with no differences in other outcomes. NHS and carer support costs were variable but, overall, were lower in the intervention arm than the TAU arm. The main limitation was difficulty maintaining outcome assessor blinding.

CONCLUSIONS

Evidence is lacking to inform frailty prevention service design, with no large-scale trials of multidomain interventions. From stakeholder/public perspectives, new frailty prevention services should be personalised and encompass multiple domains, particularly socialising and mobility, and can be delivered by trained non-specialists. Our multicomponent health promotion intervention was acceptable and delivered at modest cost. Our small study shows promise for improving clinical outcomes, including functioning and independence. A full-scale individually RCT is feasible.

FUTURE WORK

A large, definitive RCT of the HomeHealth service is warranted.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42014010370 and Current Controlled Trials ISRCTN11986672.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 21, No. 73. See the NIHR Journals Library website for further project information.

Identification of tissue-specific transcriptional markers of caloric restriction in the mouse and their use to evaluate caloric restriction mimetics

Caloric restriction (CR) without malnutrition has been shown to retard several aspects of the aging process and to extend lifespan in different species. There is strong interest in the identification of CR mimetics (CRMs), compounds that mimic the beneficial effects of CR on lifespan and healthspan without restriction of energy intake. Identification of CRMs in mammals is currently inefficient due to the lack of screening tools. We have performed whole‐genome transcriptional profiling of CR in seven mouse strains (C3H/HeJ, CBA/J, DBA/2J, B6C3F1/J, 129S1/SvImJ, C57BL/6J, and BALB/cJ) in white adipose tissue (WAT), gastrocnemius muscle, heart, and brain neocortex. This analysis has identified tissue‐specific panels of genes that change in expression in multiple mouse strains with CR. We validated a subset of genes with qPCR and used these to evaluate the potential CRMs bezafibrate, pioglitazone, metformin, resveratrol, quercetin, 2,4‐dinitrophenol, and L‐carnitine when fed to C57BL/6J 2‐month‐old mice for 3 months. Compounds were also evaluated for their ability to modulate previously characterized biomarkers of CR, including mitochondrial enzymes citrate synthase and SIRT3, plasma inflammatory cytokines TNF‐α and IFN‐γ, glycated hemoglobin (HbA1c) levels and adipocyte size. Pioglitazone, a PPAR‐γ agonist, and L‐carnitine, an amino acid involved in lipid metabolism, displayed the strongest effects on both the novel transcriptional markers of CR and the additional CR biomarkers tested. Our findings provide panels of tissue‐specific transcriptional markers of CR that can be used to identify novel CRMs, and also represent the first comparative molecular analysis of several potential CRMs in multiple tissues in mammals.

Health promotion interventions for community-dwelling older people with mild or pre-frailty: a systematic review and meta-analysis

Background

Mild or pre-frailty is common and associated with increased risks of hospitalisation, functional decline, moves to long-term care, and death. Little is known about the effectiveness of health promotion in reducing these risks. This systematic review aimed to synthesise randomised controlled trials (RCTs) evaluating home and community-based health promotion interventions for older people with mild/pre-frailty.

Methods

We searched 20 bibliographic databases and 3 trials registers (January 1990 – May 2016) using mild/pre-frailty and associated terms. We included randomised controlled and crossover trials of health promotion interventions for community-dwelling older people (65+ years) with mild/pre-frailty and excluded studies focussing on populations in hospital, long term care facilities or with a specific condition. Risk of bias was assessed by two reviewers using the Cochrane Risk of Bias tool. We pooled study results using standardised mean differences (SMD) where possible and used narrative synthesis where insufficient outcome data were available.

Results

We included 10 articles reporting on seven trials (total n = 506 participants) and included five trials in a meta-analysis. Studies were predominantly small, of limited quality and six studies tested group exercise alone. One study additionally investigated a nutrition and exercise intervention and one evaluated telemonitoring. Interventions of exercise in groups showed mixed effects on functioning (no effects on self-reported functioning SMD 0.19 (95% CI -0.57 to 0.95) n = 3 studies; positive effects on performance-based functioning SMD 0.37 (95% CI 0.07 to 0.68) n = 3 studies). No studies assessed moves to long-term care or hospitalisations.

Conclusions

Currently the evidence base is of insufficient size, quality and breadth to recommend specific health promotion interventions for older people with mild or pre- frailty. High quality studies of rigorously developed interventions are needed.

PROSPERO registration

CRD42014010370 (Review 2).

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-017-0547-8) contains supplementary material, which is available to authorized users.