Prediction of Sarcopenia Using Multiple Biomarkers of Neuromuscular Junction Degeneration in Chronic Obstructive Pulmonary Disease

Angiotensin-converting enzyme inhibitors attenuate circulating CAF22 and physical decline in congestive heart failure: Diagnostic implications of CAF22

AIMS

Age-associated muscle loss, termed sarcopenia is the major cause of physical disability in patients with congestive heart failure (CHF). Angiotensin-converting enzyme inhibitors (ACEi) are commonly used to treat CHF patients; however, their impacts on the neuromuscular junction (NMJ) and sarcopenia in CHF patients remain poorly understood. We aim to investigate the potential impact of ACEi on NMJ and CHF-induced sarcopenia.

METHODS

The cardiac function, short physical performance battery, handgrip strength (HGS), appendicular skeletal mass index, gait speed (GS) and plasma c-terminal agrin fragment-22 (CAF22), a marker of NMJ degradation, were assessed in controls (n = 81) and CHF patients treated with (n = 134) or without (n = 145) ACEi.

RESULTS

Irrespective of treatment, HGS and GS, indicators of sarcopenia, were profoundly declined in the patients with CHF vs. controls. However, patients on ACEi demonstrated significantly better HGS and GS compared to non-ACEi patients (P < .001). The level of CAF22 was significantly lower (P < .0001) in the ACEi-treated compared to non-ACEi CHF patients. Further, the level of CAF22 was inversely correlated (R2 = .33, P < .0001) with HGS in both ACEi and non-ACEi CHF patients, while CAF22 was inversely correlated with GS and short physical performance battery only in ACEi-treated but not in patients on other therapies without ACEi. The receiver operating characteristic curve analysis revealed CAF22 as a potential diagnostic marker (95% confidence interval: 0.785-0.883; P < .0001) for CHF.

CONCLUSION

Collectively, these findings strongly suggest that ACEi limits CHF-induced neuromuscular disjunction and physical disability in CHF. CAF22 has shown diagnostic implications for CHF.

Predictors of the onset of low handgrip strength in Europe: a longitudinal study of 42,183 older adults from 15 countries

OBJECTIVES

A low handgrip strength (HGS) is a significant risk factor for multiple diseases. However, most relevant studies investigate the complications of a low HGS, while the risk potential of causative factors of low HGS remain poorly characterized.

METHODS

We investigated the potentials of quality of life, depression, dyslipidaemia, diabetes mellitus, cancer, Alzheimer's disease, stroke, frailty, and difficulties performing daily activities in predicting low HGS (≤ 27 kg for men, ≤ 16 kg for women) in European older adults aged 50 or above from 15 countries (n = 42,183). All data was collected from four successive waves of survey of health, ageing, and retirement in Europe (SHARE) conducted between 2013 and 2020. Logistic models are applied, and estimated effects are presented as odds ratios and probabilities.

RESULTS

Collectively, 3016 participants (men; n = 1395; 7.38%, women; n = 1621, 6.97%) developed low HGS during the 6.5 years study period. After adjusting for covariables, we identified an advancing age (1.6-48.1% points higher risk of low HGS), male gender (1.0%-point higher risk of low HGS), lower quality of life (1.6%-point higher), and stroke (1.5%-points) as significant risk factors for low HGS. We also found a dose-dependent association of Euro-D depression scores with the risk of low HGS, as the higher scores were associated with between 0.6- and 2.3%-points higher risk of developing low HGS than participants without depression. Among physical performance indicators, difficulty climbing stairs (2.0%-points higher low HGS risk) or rising from a chair (0.7%-points) were significantly associated with developing low HGS. Lastly, frailty (0.9%-points higher risk of low HGS) and the fear of falling down (1.6%-points higher risk) also increased the risk of developing low HGS.

CONCLUSION

Altogether, we report several risk factors for developing low HGS. Our observations may help evaluating and monitoring high-risk population for developing low HGS in pre-clinical settings.

Long-term exposure to PM2.5 compositions and O3 and their interactive effects on DNA methylation of peripheral brain-derived neurotrophic factor promoter

This study examined the associations of long-term exposure to ambient fine particulate matter (PM2.5) compositions/ozone with methylation of peripheral brain-derived neurotrophic factor (BDNF) promoters. A total of 101 participants were recruited from a cohort in Shijiazhuang, Hebei province, China. They underwent baseline and follow-up surveys in 2011 and 2015. DNA methylation levels were detected by bisulfite-PCR amplification and pyrosequencing. Participants' three-year average levels of PM2.5 compositions and ozone were estimated. Bayesian kernel machine regression (BKMR) models were used to examine the joint effects of pollutants on methylation levels. Exposure to PM2.5 compositions and ozone mixtures at the 75th percentile was associated with increased methylation levels at CpG2 of BDNF promoter (203%, 95% CI: 89, 316) than the lowest level of exposure, and sulfate dominated the effect in the BKMR models.Our findings provide clues to the epigenetic mechanisms for the associations of PM2.5 compositions and ozone with BDNF.

The Association of Intestinal Leak with Sarcopenia and Physical Disability in Patients with Various Stages of Chronic Kidney Disease

Sarcopenia is related to disease severity in chronic kidney disease (CKD) patients; however, its pathophysiology remains poorly known. We investigated the associations of biomarkers of intestinal leak with sarcopenia in various stages of CKD. We recruited 61-76-year-old male controls and patients with various stages of CKD (n = 36-57/group) for measuring plasma lipopolysaccharide-binding protein (LBP) and zonulin (markers of intestinal leak), handgrip strength (HGS), skeletal mass index (SMI), and gait speed (markers of sarcopenia), and short physical performance battery (SPPB; marker of physical capacity). CKD stages 4 and 5 were associated with lower HGS, SMI, gait speed, and cumulative SPPB scores and a higher sarcopenia prevalence than controls and patients with CKD stages 1 and 2 (all p < 0.05). CKD patients (stages 1 and 2) had elevated plasma zonulin and LBP when compared with CKD stages 4 and 5. Plasma zonulin and LBP exhibited significant correlations with renal function, HGS, gait speed, SPPB scores, and oxidative stress markers in CKD stages 4 and 5 (all p < 0.05). However, similar relations were not found in early CKD. Collectively, intestinal leak may be contributing to sarcopenia and physical disability in the advanced stages of CKD.

Dietary Protein and Physical Exercise for the Treatment of Sarcopenia

Sarcopenia is a multifactorial age-related disorder that causes a decrease in muscle mass, strength, and function, leading to alteration of movement, risk of falls, and hospitalization. This article aims to review recent findings on the factors underlying sarcopenia and the strategies required to delay and counteract its symptoms. We focus on molecular factors linked to ageing, on the role of low-grade chronic and acute inflammatory conditions such as cancer, which contributes to the onset of sarcopenia, and on the clinical criteria for its diagnosis. The use of drugs against sarcopenia is still subject to debate, and the suggested approaches to restore muscle health are based on adequate dietary protein intake and physical exercise. We also highlight the difference in the amount and quality of amino acids within animal- and plant-based diets, as studies have often shown varying results regarding their effect on sarcopenia in elderly people. In addition, many studies have reported that non-pharmacological approaches, such as an optimization of dietary protein intake and training programs based on resistance exercise, can be effective in preventing and delaying sarcopenia. These approaches not only improve the maintenance of skeletal muscle function, but also reduce health care costs and improve life expectancy and quality in elderly people.

Predictors of hip fracture in 15 European countries: a longitudinal study of 48,533 geriatric adults using SHARE dataset

We investigated the risk factors for hip fracture in 48,533 European older adults for 8 years from 2013 onward. We identified female gender, age above 80, low handgrip strength, and depression as significant risk factors for hip fracture. Our findings may help identify high-risk populations for hip fractures in pre-clinical settings.

OBJECTIVES

Hip fracture is a major cause of functional disability, mortality, and health costs. However, the identification and characterization of its causative factors remain poor.

METHODS

We investigated demography, handgrip strength (HGS), depression, and multiple age-associated comorbidities for predicting future hip fracture in individuals aged 50 or above from 15 European countries (n = 48,533). All participants were evaluated from 2013 to 2020 using four successive waves of the Survey of Health, Aging, and Retirement in Europe (SHARE).

RESULTS

Altogether, 1130 participants developed hip fractures during the study period. We identified female gender, an advancing age from quinquagenarians onward, and a poor socioeconomic status as critical risk factors for future hip fracture. Having mobility difficulty, a low HGS (< 27 kg in men, < 16 kg in women) and higher scores on Euro-D depression scales were also significant risk factors for hip fracture. Summated scales of hypertension, diabetes mellitus, cancer, Alzheimer's disease, and stroke did not appear as risk factors.

CONCLUSION

Collectively, we report advancing age, female gender, low HGS, and depression as independent risk factors for hip fracture. Our findings are useful in identifying high-risk populations for hip fractures in pre-clinical settings before rigorous evaluation and treatment in clinics.

Plasma levels of Neurofilament light chain correlate with handgrip strength and sarcopenia in patients with chronic obstructive pulmonary disease

BACKGROUND

Age-associated muscle decline, termed sarcopenia, is a common systemic effect of chronic obstructive pulmonary disease (COPD). Circulating Neurofilament light chain (NfL) levels reflect neuronal degradation and may be relevant to sarcopenia phenotype. However, such an association in COPD patients remains elusive.

METHODS

We investigated male, 60-76 years old controls (n = 50) and COPD patients (n = 139) for plasma NfL levels in relation to sarcopenia and physical capacity markers. We measured handgrip strength (HGS), body composition, and short physical performance battery (SPPB) to evaluate sarcopenia and physical capacity.

RESULTS

COPD patients had higher plasma NfL and lower HGS and SPPB performance than controls. Plasma NfL levels demonstrated negative associations with HGS and gait speed in COPD patients (all p < 0.05). Further, NfL levels were negatively associated with total SPPB scores in controls and patients with advanced COPD (p < 0.05). Plasma NfL also demonstrated an acceptable accuracy in diagnosing sarcopenia in controls (AUC = 0.757, p < 0.05) and COPD (AUC = 0.806, p < 0.05) patients.

CONCLUSION

Collectively, plasma NfL may be helpful in evaluating sarcopenia phenotype and physical capacity in geriatric patients with COPD.

Resistance Exercise Reduces Sarcopenia by Repairing Leaky Gut in Patients with Alzheimer's Disease

PURPOSE

Sarcopenia or age-associated muscle loss is common in patients with Alzheimer's disease (AD). We have previously demonstrated the contribution of a leaky gut to sarcopenia in AD. Here, we asked whether resistant exercise (RE) reduces the sarcopenia phenotype by repairing intestinal leakage in patients with AD.

METHOD

A prospective, single-center study of older adults, including healthy controls and patients with AD (n = 44-51/group), was conducted to measure plasma zonulin and claudin-3 (markers of intestinal leakage), handgrip strength (HGS), and short physical performance battery (SPPB) as a measure of functional capacity. Measurements in patients with AD were performed at baseline and after 12 weeks of RE.

RESULTS

At baseline, patients with AD had higher plasma zonulin and claudin-3 and lower HGS, gait speed, and SPPB scores than controls. RE reduced plasma zonulin and claudin-3 levels and improved HGS, SPPB scores, and gait speed. Regression analysis revealed robust relationships between changes in plasma zonulin and claudin-3 with HGS. Plasma zonulin was also positively associated with SPPB scores. In addition, RE downregulated plasma markers of inflammation and oxidative stress. However, the prevalence of sarcopenia based on low HGS and muscle atrophy or low SPPB was not affected by RE.

CONCLUSION

Taken together, disruption of the intestinal mucosal barrier may contribute to functional decline and sarcopenia in AD, which is incompletely recovered by RE. Circulating levels of zonulin and claudin-3 may be valuable in predicting sarcopenia and functional capacity in older adults with AD.

Probiotics Supplements Improve the Sarcopenia-Related Quality of Life in Older Adults with Age-Related Muscle Decline

A pathological increase in intestinal leak is implicated in age-associated muscle loss, termed sarcopenia, and reduced sarcopenia-related quality-of-life (SarQoL). However, the potential therapies remain elusive. We investigated the effects of probiotic supplementation on sarcopenia and SarQoL in geriatric older adults. We randomized sarcopenic men into placebo (age = 71.4 ± 3.9 years, n = 63) and probiotic (age = 73 ± 4.1 years, n = 60) groups for 16 weeks. The probiotic used was one capsule daily of Vivomix 112 billion for 16 weeks. We measured sarcopenia parameters of handgrip strength (HGS) and skeletal mass index (SMI), plasma zonulin (marker of the intestinal leak), and SarQoL using a targeted questionnaire. Probiotics improved the SarQoL scores for locomotion, functionality, and activities of daily living and prevented a decline in cumulative SarQoL observed in the placebo group (all p < 0.05). Probiotic supplementation also reduced plasma zonulin and marker of systemic bacterial load. These changes were accompanied by an increase in HGS and maintenance of gait speed in the probiotic group compared to the placebo group. Correlation analysis revealed significant associations of cumulative SarQoL scores with plasma zonulin and HGS in the probiotic group. Collectively, probiotics improved SarQoL and HGS by repairing pathological intestinal leak. Future studies may further dissect the relation between intestinal leak and SarQoL in older adults taking probiotics.

Diabetes Mellitus Should Be Considered While Analysing Sarcopenia-Related Biomarkers

Sarcopenia is a chronic, progressive skeletal muscle disease characterised by low muscle strength and quantity or quality, leading to low physical performance. Patients with type 2 diabetes mellitus (T2DM) are more at risk of sarcopenia than euglycemic individuals. Because of several shared pathways between the two diseases, sarcopenia is also a risk factor for developing T2DM in older patients. Various biomarkers are under investigation as potentially valuable for sarcopenia diagnosis and treatment monitoring. Biomarkers related to sarcopenia can be divided into markers evaluating musculoskeletal status (biomarkers specific to muscle mass, markers of the neuromuscular junction, or myokines) and markers assuming causal factors (adipokines, hormones, and inflammatory markers). This paper reviews the current knowledge about how diabetes and T2DM complications affect potential sarcopenia biomarker concentrations. This review includes markers recently proposed by the expert group of the European Society for the Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) as those that may currently be useful in phase II and III clinical trials of sarcopenia: myostatin (MSTN); follistatin (FST); irisin; brain-derived neurotrophic factor (BDNF); procollagen type III N-terminal peptide (PIIINP; P3NP); sarcopenia index (serum creatinine to serum cystatin C ratio); adiponectin; leptin; insulin-like growth factor-1 (IGF-1); dehydroepiandrosterone sulphate (DHEAS); C-reactive protein (CRP); interleukin-6 (IL-6), and tumor necrosis factor α (TNF-α). A better understanding of factors influencing these biomarkers' levels, including diabetes and diabetic complications, may lead to designing future studies and implementing results in clinical practice.

A leaky gut contributes to reduced sarcopenia-related quality of life (SarQoL) in geriatric older adults

PURPOSE

The sarcopenia quality-of-life (SarQoL) questionnaire is designed to evaluate the quality of life of sarcopenic patients. A pathological increase in intestinal permeability leads to several systemic diseases, but its contribution to SarQoL is unknown.

METHODS

We recruited controls (n = 84, age = 74.6 ± 4.9 years) and sarcopenic (n = 55, age = 76.1 ± 4.2 years) men for validating and adapting a Pashto version of SarQoL. We measured the scores for seven domains of SarQoL, body composition, and handgrip strength (HGS). We also measured plasma zonulin as a marker of increased intestinal permeability.

RESULTS

The Pashto SarQoL exhibited adequate discriminative ability, construct validity, internal consistency, and test-retest reliability, without exhibiting the floor and ceiling effect. Sarcopenic patients had higher plasma zonulin and lower scores on SarQoL domains for physical and mental health, locomotion, body composition, functionality, activities of daily living, leisure, and fear, and cumulative SarQoL scores than controls. Plasma zonulin exhibited significant coefficients of determination with Pashto SarQoL domains for locomotion (r2 = 0.217), functionality (r2 = 0.101), activities of daily living (r2 = 0.302), and cumulative SarQoL scores (r2 = 0.168). We also found high efficacies of zonulin in diagnosing low scores for functionality (AUC = 0.785, 95% C.I = 0.708-0.863), activities of daily living (AUC = 0.785, 95% C.I = 0.708-0.863), and cumulative SarQoL scores (AUC = 0.821, 95% C.I = 0.751-0.891).

CONCLUSION

Altogether, SarQoL appears reliable in measuring the quality of life in sarcopenic patients. A leaky gut has a potential contribution to reduced SarQoL in sarcopenia.

Butyrate supplementation reduces sarcopenia by repairing neuromuscular junction in patients with chronic obstructive pulmonary disease

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is associated with an intestinal leak and neuromuscular junction (NMJ) degradation, which contributes to physical compromise and accelerated age-related muscle loss, called sarcopenia. However, the relevant interventions partly remain ineffective. We investigated the effects of exogenous butyrate on sarcopenia and physical capacity with relevance to intestinal permeability and NMJ integrity in COPD patients.

METHODS

COPD patients were randomized into placebo (n = 67) and butyrate (n = 64) groups in a double-blind manner. The patients in the butyrate group received one 300 mg capsule a day for 12 weeks. We measured circulating markers of intestinal leak (zonulin), systemic bacterial load (LBP), and NMJ loss (CAF22), along with handgrip strength (HGS), and short physical performance battery (SPPB) at baseline and 12 weeks.

RESULTS

Butyrate supplementation improved HGS and gait speed in COPD patients. Among SPPB indices, butyrate improved the ability to maintain postural balance and walking and prevented a decline in the ability to rise from a chair. Butyrate also reduced the plasma levels of zonulin, LBP, and CAF22 levels in COPD patients (all p < 0.05). Regression analysis revealed significant associations of plasma zonulin and CAF22 with HGS, gait speed, and cumulative SPPB scores in butyrate group. These changes were associated with reduced markers of inflammation and muscle damage.

CONCLUSION

Butyrate may provide a therapeutic approach to sarcopenia and physical dependency in COPD by repairing intestinal leak and NMJ loss.

Angiotensin Receptor Blockers Restore Skeletal Muscle in Patients with Chronic Obstructive Pulmonary Disease

BACKGROUND

Age-related muscle decline, called sarcopenia, and hypertension are commonly observed in patients with chronic obstructive pulmonary disease (COPD). Angiotensin receptor blockers (ARBs) are common antihypertensive medications with muscle protective effects. However, the anti-sarcopenic potential and associated mechanisms of ARBs in hypertensive patients with COPD are unknown.

OBJECTIVES

We aimed to investigate the potential contribution of neuromuscular junction (NMJ) stability as a driving mechanism of ARBs-induced muscle protection.

METHODS

We categorized 236 patients with COPD into normotensive (n = 79) and hypertensive, based on treatment with ARB (n = 82), and other antihypertensive drugs (n = 75). Hypertensive patients with COPD were evaluated at two time points one year apart. Handgrip strength (HGS), body composition, short physical performance battery (SPPB), and plasma c-terminal agrin fragment-22 (CAF22) as a marker of NMJ degradation were measured.

RESULTS

Patients with COPD exhibited reduced HGS and SPPB scores, and higher levels of CAF22 than controls, regardless of hypertension status. ARBs treatment improved HGS and gait speed and reduced plasma CAF22 levels in hypertensive patients with COPD (all p <0.05). ARBs also prevented the decline in SPPB components, including maintaining balance, gait speed, and the ability to rise from a chair in hypertensive patients with COPD (all p <0.05). We also found dynamic associations of plasma CAF22 with HGS, gait speed, and SPPB scores in hypertensive patients with COPD.

CONCLUSIONS

Altogether, ARB treatment preserves skeletal muscle health and functional capacity in hypertensive patients with COPD by reducing plasma CAF22 and possibly repairing NMJs.

The quality of life in Alzheimer's disease is not associated with handgrip strength but with activities of daily living-a composite study from 28 European countries

OBJECTIVES

The relationship between handgrip strength (HGS) and quality of life is inconsistent. The purpose of this study was to investigate the potential association between HGS and quality of life in the settings of ageing and Alzheimer's disease (AD).

METHODS

We investigated the HGS, CASP-12 (control, autonomy, self-realization, and pleasure) measure of quality of life, and physical capacity in European adults above 50, including controls (n = 38,628) and AD subjects (n = 460) using the survey of health, ageing, and retirement in Europe (SHARE; 2022).

RESULTS

AD subjects exhibited lower HGS and CASP-12 scores than controls (both p < 0.05). Participants with higher CASP-12 quartiles had higher HGS in controls but not in AD subjects. A linear positive relation was found between HGS and CASP-12 in controls (0.0842, p < 0.05) but not in AD subjects (0.0636, p = 0.091). There was no effect of gender on this finding. Lastly, we found significant negative associations of difficulties walking, rising from chair, climbing stairs, and fatigue with CASP-12 scores in controls and AD subjects (all p < 0.05).

CONCLUSIONS

Altogether, HGS was not associated with quality of life in individuals with AD. Conversely, difficulties in activities of daily living seem to be negatively associated with quality of life; thus, strategies are recommended to improve physical capacity.

A leaky gut contributes to postural dysfunction in patients with Alzheimer's disease

Background

Postural dysfunction is a common problem in patients with Alzheimer's disease (AD) and may lead to functional dependency and increasing morbidity and mortality. However, the pathophysiology of postural dysfunction in AD patients remains poorly understood.

Objectives

Elevated intestinal permeability is an underlying contributor to multiple diseases, including AD. We aimed to investigate the association of elevated intestinal permeability with postural dysfunction in AD patients.

Design Setting Participants Measurements

We conducted a cross-sectional, observational study on older adults, including controls and AD patients. We investigated the associations of postural balance with plasma zonulin, a marker of elevated intestinal permeability in geriatric controls (n = 74) and patients with mild (n = 71) and moderate (n = 66) AD. We used a standardized physical performance battery to measure balance in supine, tandem, and semi-tandem positions. We also measured handgrip strength (HGS), and gait speed as markers of physical capacity.

Results

AD patients exhibited lower balance scores, HGS, and gait speed and higher plasma zonulin than in controls (all p < 0.05). Plasma zonulin levels demonstrated significant areas under the curves in diagnosing poor balance in AD patients (all p < 0.05). Moderate AD was associated with lower balance and physical capacity, and higher zonulin than mild AD (ALL P < 0.05). Poor scores on balance scale were associated with higher expressions of markers of inflammation, oxidative stress, and muscle damage providing a mechanistic link between increased intestinal permeability and postural dysfunction in AD patients.

Conclusion

The results of our study show that plasma zonulin measurement may be used to diagnose postural dysfunction in AD patients. The study is relevant to non-ambulant and/or comatose AD patients with postural dysfunction. Our findings also highlight the therapeutic potential of repairing the intestinal leak to improve postural control and reduce the risk of falls in AD patients.

Statin Therapy Induces Gut Leakage and Neuromuscular Disjunction in Patients With Chronic Heart Failure

ABSTRACT

Statins are commonly used to limit the risk of cardiovascular diseases, including ischemic heart attack and stroke. However, treatment often leads to myopathy and muscle weakness. Therefore, a better understanding of underlying pathomechanism is needed to improve the clinical outcomes. Here, we assessed the physical performance, including handgrip strength (HGS), gait speed (GS), and short physical performance battery, in 172 patients diagnosed with chronic heart failure (CHF) treated with (n = 50) or without (n = 122) statin and 59 controls. The plasma biomarkers, including sarcopenia marker C-terminal agrin fragment-22 (CAF22), intestinal barrier integrity marker zonulin, and C-reactive protein (CRP), were measured and correlated with the physical performance of patients. The HGS, short physical performance battery scores, and GS were significantly compromised in patients with CHF versus controls. Irrespective of etiology, significant elevation of plasma CAF22, zonulin, and CRP was observed in patients with CHF. There were strong inverse correlations of CAF22 with HGS (r 2 = 0.34, P < 0.0001), short physical performance battery scores (r 2 = 0.08, P = 0.0001), and GS (r 2 = 0.143, P < 0.0001). Strikingly, CAF22 and zonulin were positively correlated with each other (r 2 = 0.10, P = 0.0002) and with the level of CRP in patients with CHF. Further investigations revealed a significant induction of CAF22, zonulin, and CRP in patients with CHF taking statin versus nonstatin group. Consistently, HGS and GS were significantly lower in the statin versus nonstatin CHF patients' group. Collectively, statin therapy adversely affects the neuromuscular junction and intestinal barrier, which potentially induces systemic inflammation and physical disability in patients with CHF. Further prospective confirmation of the findings is required in a well-controlled study.

ACE Inhibitors Improve Skeletal Muscle by Preserving Neuromuscular Junctions in Patients with Alzheimer's Disease

BACKGROUND

Hypertension and skeletal muscle decline are common findings in patients with Alzheimer's disease (AD). Angiotensin-converting enzyme (ACE) inhibitors preserve skeletal muscle and physical capacity; however, the driving mechanisms are poorly understood.

OBJECTIVE

We investigated the effects of ACE inhibitors on the neuromuscular junction (NMJ) with relevance to skeletal muscle and physical capacity in AD patients and age-matched controls.

METHODS

We evaluated controls (n = 59) and three groups of AD patients, including normotensive (n = 51) and patients with hypertension taking ACE inhibitors (n = 53) or other anti-hypertensive medications (n = 49) at baseline and one year later. We measure plasma c-terminal agrin fragment-22 (CAF22) as a marker of NMJ degradation, handgrip strength (HGS), and Short Physical Performance Battery (SPPB) as markers of physical capacity.

RESULTS

At baseline AD patients demonstrated lower HGS and SPPB scores and higher CAF22 levels than controls, irrespective of the hypertension status (all p < 0.05). The use of ACE inhibitors was associated with higher HGS and relative maintenance of SPPB scores, gait speed, and plasma CAF22 levels. Conversely, other anti-hypertensive medications were associated with an unaltered HGS, reduced SPPB scores and elevated plasma CAF22 levels (both p < 0.05). We also found dynamic associations of CAF22 with HGS, gait speed, and SPPB in AD patients taking ACE inhibitors (all p < 0.05). These changes were associated with reduced oxidative stress in AD patients taking ACE inhibitors (p < 0.05).

CONCLUSION

Altogether, ACE inhibitors are associated with higher HGS, preserved physical capacity, and the prevention of NMJ degradation in hypertensive AD patients.

Degradation of neuromuscular junction contributes to muscle weakness but not physical compromise in chronic obstructive pulmonary disease patients taking lipids-lowering medications

OBJECTIVES

The relevant data about the effects and the associated mechanisms of statins on muscle strength and physical capacity is inconsistent. We investigated the potential contribution of neuromuscular junction (NMJ) degradation to muscle weakness and physical compromise in patients with chronic obstructive pulmonary disease (COPD) on statins.

METHOD

We recruited male COPD patients (age range = 63-75 years, n = 150) as nonusers (n = 71) and users of statin medications (n = 79) along with age-matched controls (n = 76). The COPD patients were evaluated at baseline and one year later. The data about handgrip strength (HGS), body composition, short physical performance battery (SPPB), and plasma c-terminal agrin fragment-22 (CAF22) as a marker of NMJ disintegration was collected at two time points.

RESULTS

We observed lower HGS, SPPB scores, and higher CAF22 levels in all COPD patients than controls, irrespective of the treatment status (all p < 0.05). Statins further reduced HGS and elevated CAF22 in COPD patients (both p < 0.05). The decline in SPPB was relatively modest in statin users (≈3.7%, p = 0.032) than in nonusers (≈8.7%, p = 0.002). The elevated plasma CAF22 exhibited robust negative correlations with a reduction in HGS but not with SPPB in COPD patients taking statins. We also found a reduction in markers of inflammation and no increase in oxidative stress markers following statin use in COPD patients.

CONCLUSION

Altogether, statin-induced NMJ degradation exacerbates muscle decline but does not contribute to physical compromise in COPD patients.

C-terminal agrin fragment as a biomarker of muscle wasting and weakness: a narrative review

Ageing is accompanied by an inexorable loss of muscle mass and functionality and represents a major risk factor for numerous diseases such as cancer, diabetes and cardiovascular and pulmonary diseases. This progressive loss of muscle mass and function may also result in the insurgence of a clinical syndrome termed sarcopenia, exacerbated by inactivity and disease. Sarcopenia and muscle weakness yield the risk of falls and injuries, heavily impacting on health and social costs. Thus, screening, monitoring and prevention of conditions inducing muscle wasting and weakness are essential to improve life quality in the ageing modern society. To this aim, the reliability of easily accessible and non-invasive blood-derived biomarkers is being evaluated. C-terminal agrin fragment (CAF) has been widely investigated as a neuromuscular junction (NMJ)-related biomarker of muscle dysfunction. This narrative review summarizes and critically discusses, for the first time, the studies measuring CAF concentration in young and older, healthy and diseased individuals, cross-sectionally and in response to inactivity and physical exercise, providing possible explanations behind the discrepancies observed in the literature. To identify the studies investigating CAF in the above-mentioned conditions, all the publications found in PubMed, written in English and measuring this biomarker in blood from 2013 (when CAF was firstly measured in human serum) to 2022 were included in this review. CAF increases with age and in sarcopenic individuals when compared with age-matched, non-sarcopenic peers. In addition, CAF was found to be higher than controls in other muscle wasting conditions, such as diabetes, COPD, chronic heart failure and stroke, and in pancreatic and colorectal cancer cachectic patients. As agrin is also expressed in kidney glomeruli, chronic kidney disease and transplantation were shown to have a profound impact on CAF independently from muscle wasting. CAF concentration raises following inactivity and seems to be lowered or maintained by exercise training. Finally, CAF was reported to be cross-sectionally correlated to appendicular lean mass, handgrip and gait speed; whether longitudinal changes in CAF are associated with those in muscle mass or performance following physical exercise is still controversial. CAF seems a reliable marker to assess muscle wasting in ageing and disease, also correlating with measurements of appendicular lean mass and muscle function. Future research should aim at enlarging sample size and accurately reporting the medical history of each patient, to normalize for any condition, including chronic kidney disease, that may influence the circulating concentration of this biomarker.

Effect of targeted intervention on C-terminal agrin fragment and its association with the components of sarcopenia: a scoping review

BACKGROUND

C-terminal Agrin Fragment (CAF) has emerged as a potent biomarker for identifying sarcopenia. However, the effect of interventions on CAF concentration and the association of CAF with sarcopenia components are unclear.

OBJECTIVE

To review the association between CAF concentration and muscle mass, muscle strength, and physical performance among individuals with primary and secondary sarcopenia and to synthesize the effect of interventions on the change in the level of CAF concentration.

METHODS

A systematic literature search was conducted in six electronic databases, and studies were included if they met the selection criteria decided a priori. The data extraction sheet was prepared, validated, and extracted relevant data.

RESULTS

A total of 5,158 records were found, of which 16 were included. Among studies conducted on individuals with primary sarcopenia, muscle mass was significantly associated with CAF levels, followed by hand grip strength (HGS) and physical performance, with more consistent findings in males. While in secondary sarcopenics, the strongest association was found for HGS and CAF levels, followed by physical performance and muscle mass. CAF concentration was reduced in trials that used functional, dual task, and power training, whereas resistance training and physical activity raised CAF levels. Hormonal therapy did not affect serum CAF concentration.

CONCLUSION(S)

The association between CAF and sarcopenic assessment parameters varies in primary and secondary sarcopenics. The findings would help practitioners and researchers choose the best training mode/parameters/exercises to reduce CAF levels and, eventually, manage sarcopenia.

Plasma Galectin-3 and H-FABP correlate with poor physical performance in patients with congestive heart failure

Heart failure (HF) is often associated with compromised physical capacity in patients. However, it is unclear if established HF markers correlate with the physical performance of patients with congestive HF (CHF). We assessed the left ventricular end-systolic dimension (LVESD) and ejection fraction (LVEF) and, physical performance parameters, including short physical performance battery (SPPB), gait speed (GS), and handgrip strength (HGS) in 80 patients with CHF along with 59 healthy controls. Furthermore, levels of plasma HF markers galectin-3 and heart-specific fatty acid binding protein (H-FABP) were measured in relation to the severity of HF and physical performance. Irrespective of etiology, significantly greater LVESD and lower LVEF were observed in HF patients versus controls. As expected, the levels of HF markers galectin-3 and H-FABP were upregulated in the CHF patients which were accompanied by significantly elevated levels of plasma zonulin and inflammatory marker C-reactive protein (CRP). The SPPB scores, GS, and HGS were significantly lower in the ischemic and non-ischemic HF patients than controls. The level of galectin-3 was inversely correlated with SPPB scores (r2 = 0.089, P = 0.01) and HGS (r2 = 0.078, P = 0.01). Similarly, H-FABP levels were also inversely correlated with SPPB scores (r2 = 0.06, P = 0.03) and HGS (r2 = 0.109, P = 0.004) in the patients with CHF. Taken together, CHF adversely affects physical performance, and galectin-3 and H-FABP may serve as biomarkers of physical disability in patients with CHF. The robust correlations of galectin-3 and H-FABP with the physical performance parameters and CRP in CHF patients suggest that the poor physical performance may partly be caused due to systemic inflammation.

Biochemical Markers of Musculoskeletal Health and Aging to be Assessed in Clinical Trials of Drugs Aiming at the Treatment of Sarcopenia: Consensus Paper from an Expert Group Meeting Organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the Centre Académique de Recherche et d'Expérimentation en Santé (CARES SPRL), Under the Auspices of the World Health Organization Collaborating Center for the Epidemiology of Musculoskeletal Conditions and Aging

In clinical trials, biochemical markers provide useful information on the drug's mode of action, therapeutic response and side effect monitoring and can act as surrogate endpoints. In pharmacological intervention development for sarcopenia management, there is an urgent need to identify biomarkers to measure in clinical trials and that could be used in the future in clinical practice. The objective of the current consensus paper is to provide a clear list of biochemical markers of musculoskeletal health and aging that can be recommended to be measured in Phase II and Phase III clinical trials evaluating new chemical entities for sarcopenia treatment. A working group of the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) proposed classifying biochemical markers into 2 series: biochemical markers evaluating musculoskeletal status and biochemical markers evaluating causal factors. For series 1, the group agreed on 4 biochemical markers that should be assessed in Phase II or Phase III trials (i.e., Myostatin-Follistatin, Brain Derived Neurotrophic Factor, N-terminal Type III Procollagen and Serum Creatinine to Serum Cystatin C Ratio - or the Sarcopenia Index). For series 2, the group agreed on 6 biochemical markers that should be assessed in Phase II trials (i.e., the hormones insulin-like growth factor-1 (IGF-I), dehydroepiandrosterone sulphate, and cortisol, and the inflammatory markers C-reactive protein (CRP), interleukin-6 and tumor necrosis factor-α), and 2 in Phase III trials (i.e., IGF-I and CRP). The group also proposed optional biochemical markers that may provide insights into the mode of action of pharmacological therapies. Further research and development of new methods for biochemical marker assays may lead to the evolution of these recommendations.

Effects of a 2-year exercise training on neuromuscular system health in older individuals with low muscle function

BACKGROUND

Ageing is accompanied by a progressive loss of skeletal muscle mass and strength, potentially determining the insurgence of sarcopenia. Evidence suggests that motoneuron and neuromuscular junction (NMJ) degeneration contribute to sarcopenia pathogenesis. Seeking for strategies able to slow down sarcopenia insurgence and progression, we investigated whether a 2-year mixed-model training involving aerobic, strength and balance exercises would be effective for improving or preserving motoneuronal health and NMJ stability, together with muscle mass, strength and functionality in an old, sarcopenic population.

METHODS

Forty-five sarcopenic elderly (34 females; 11 males) with low dual-energy X-ray absorptiometry (DXA) lean mass and Short Physical Performance Battery (SPPB) score <9 were randomly assigned to either a control group [Healthy Aging Lifestyle Education (HALE), n = 21] or an intervention group [MultiComponent Intervention (MCI), n = 24]. MCI trained three times per week for 2 years with a mix of aerobic, strength and balance exercises matched with nutritional advice. Before and after the intervention, ultrasound scans of the vastus lateralis (VL), SPPB and a blood sample were obtained. VL architecture [pennation angle (PA) and fascicle length (Lf)] and cross-sectional area (CSA) were measured. As biomarkers of neuronal health and NMJ stability status, neurofilament light chain (NfL) and C-terminal agrin fragment (CAF) concentrations were measured in serum. Differences in ultrasound parameters, NfL and CAF concentration and physical performance between baseline and follow-up were tested with mixed ANOVA or Wilcoxon test. The relationship between changes in physical performance and NfL or CAF concentration was assessed through correlation analyses.

RESULTS

At follow-up, MCI showed preserved VL architecture (PA, Lf) despite a reduced CSA (-8.4%, P < 0.001), accompanied by maintained CAF concentration and ameliorated overall SPPB performance (P = 0.007). Conversely, HALE showed 12.7% decrease in muscle CSA (P < 0.001), together with 5.1% and 5.5% reduction in PA and Lf (P < 0.001 and P = 0.001, respectively), and a 6.2% increase in CAF (P = 0.009) but improved SPPB balance score (P = 0.007). NfL concentration did not change in either group. In the population, negative correlations between changes in CAF concentration and SPPB total score were found (P = 0.047), whereas no correlation between NfL and SPPB variations was observed.

CONCLUSIONS

The present findings suggest that our 2-year mixed aerobic, strength and balance training seemed effective for preventing the age and sarcopenia-related increases in CAF concentration, preserving NMJ stability as well as muscle structure (PA and Lf) and improving physical performance in sarcopenic older individuals.

Elevated plasma CAF22 are incompletely restored six months after COVID-19 infection in older men

INTRODUCTION

The long-term complications of COVID-19 appear as significant health problems. However, the long-term muscle decline in these patients is poorly characterized.

METHODS

We investigated the age-related muscle decline, termed sarcopenia, before and following the COVID-19 infection in older male patients (n = 87). We evaluated handgrip strength (HGS) and functional capacity (short physical performance battery; SPPB) in COVID-19 patients 7-42 days before and one week and 6-month after COVID-19 infection. We used ELISA tests to measure plasma c-terminal agrin fragment-22 (CAF22), c-reactive protein (CRP), and 8-isoprostanes as markers of degraded neuromuscular junctions, inflammation, and oxidative stress, respectively.

RESULTS

Before the COVID-19 infection, 54 patients were non-sarcopenic, and 25 patients were sarcopenic, while eight patients subsequently developed sarcopenia. All patients exhibited reduced HGS and SPPB, while elevated CAF22, CRP, and 8-isoprostane levels one week post-COVID-19 infection (all p < 0.05). At six months post-COVID-19 infection, the HGS, SPPB, CAF22, CRP, and 8-isoprostanes were partly restored to baseline levels (all p < 0.05). Correlation analysis revealed that the plasma CAF22 had a significant correlation with HGS, SPPB, and COVID-19 disease severity. CAF22 also demonstrated significant areas under the curves in diagnosing sarcopenia at all three time-points.

CONCLUSION

Altogether, the muscle detriment due to COVID-19 persists six months post-infection, and plasma CAF22 may be helpful to detect muscle and functional decline in these patients. Timely evaluation and intervention of sarcopenia may be critical in COVID-19 treatment.

A multistrain probiotic improves handgrip strength and functional capacity in patients with COPD: A randomized controlled trial

PURPOSE

The age-related muscle loss, termed sarcopenia and functional dependency, are common findings in patients with chronic obstructive pulmonary disease (COPD). However, an effective bedside treatment remains elusive.

OBJECTIVE

To assess the effects of probiotics on sarcopenia and physical capacity in COPD patients.

METHODS

Randomized, double-blind, computer-controlled, multicenter trial in two tertiary-care hospitals for 16 weeks. A central computer system randomly allocated male, 63-73 years old COPD patients into placebo (n=53) and probiotic (n=51) groups. The intervention was Vivomix 112 billion*, one capsule a day for 16 weeks. The main outcomes measured were sarcopenia phenotype, short physical performance battery (SPPB), plasma markers of intestinal permeability (zonulin and claudin-3) and neuromuscular junction degradation (CAF22), body composition, and handgrip strength (HGS) before and following the probiotics treatment.

FINDINGS

4 patients discontinued intervention due to poor compliance and 100 patients, including placebo (n=53) and probiotic (n=47) groups were analyzed. Probiotics reduced plasma zonulin, claudin-3, and CAF22, along with an improvement in HGS, gait speed, and SPPB scores (all p<0.05). Probiotic treatment also reduced the plasma c-reactive proteins and 8-isoprostane levels, the markers of systemic inflammation and oxidative stress (p<0.05). Correlation analysis revealed varying degrees of association of plasma biomarkers with sarcopenia indexes. Despite a statistical trend, we did not find a reduction in sarcopenia prevalence in the probiotic group.

CONCLUSION

Taken together, the multistrain probiotic improves muscle strength and functional performance in COPD patients by reducing intestinal permeability and stabilizing neuromuscular junction.

TRIAL REGISTRATION

GMC clinical trial unit, GMC-CREC-00263.

Suppression of endoplasmic reticulum stress prevents disuse muscle atrophy in a mouse model of microgravity

BACKGROUND

Hind-limb unloaded (HLU) mouse model exhibits skeletal muscle atrophy and weakness mimicking the conditions such as prolonged spaceflight. However, the molecular mechanisms and interventions of muscle loss during muscle unloading remain elusive. Dysfunction of protein folding by ednoplasmic reticulum (ER), a condition called ER stress, is implicated in diseases of various cell types, but its contribution to skeletal muscle detriment remains elusive. In this study, we investigated the contribution of ER stress to muscle atrophy.

METHODS

Sixteen-week-old c57BL/6j male mice were grouped into ground-based controls and HLU group, which was subsequently injected with injected saline (HLU-sal.) or pan-ER stress inhibitor 4-PBA (100mg/kg/d; HLU- 4PBA) via intraperitoneal injections for three weeks.

RESULTS

Three weeks of HLU resulted in reduction in muscle mass and strength, which were restored with 4PBA injections. We also report myofibers atrophy, myonuclear apoptosis, and aterations in the expressions of genes associated with ER stress, apoptosis, and calcium dysregulation. These findings were reversed by 4-PBA treatment.

CONCLUSION

Altogether, our results indicate that ER stress contributes to muscle atrophy in HLU conditions. We suggest that blocking ER stress may be an effective pharmacological therapy to prevent muscle weakness and atrophy during prolonged muscle unloading.

Integrating Mechanisms of Exacerbated Atrophy and Other Adverse Skeletal Muscle Impact in COPD

The normal decline in skeletal muscle mass that occurs with aging is exacerbated in patients with chronic obstructive pulmonary disease (COPD) and contributes to poor health outcomes, including a greater risk of death. There has been controversy about the causes of this exacerbated muscle atrophy, with considerable debate about the degree to which it reflects the very sedentary nature of COPD patients vs. being precipitated by various aspects of the COPD pathophysiology and its most frequent proximate cause, long-term smoking. Consistent with the latter view, recent evidence suggests that exacerbated aging muscle loss with COPD is likely initiated by decades of smoking-induced stress on the neuromuscular junction that predisposes patients to premature failure of muscle reinnervation capacity, accompanied by various alterations in mitochondrial function. Superimposed upon this are various aspects of COPD pathophysiology, such as hypercapnia, hypoxia, and inflammation, that can also contribute to muscle atrophy. This review will summarize the available knowledge concerning the mechanisms contributing to exacerbated aging muscle affect in COPD, consider the potential role of comorbidities using the specific example of chronic kidney disease, and identify emerging molecular mechanisms of muscle impairment, including mitochondrial permeability transition as a mechanism of muscle atrophy, and chronic activation of the aryl hydrocarbon receptor in driving COPD muscle pathophysiology.

Plasma levels of myokines and inflammatory markers are related with functional and respiratory performance in older adults with COPD and sarcopenia

This study investigated whether blood-based biomarkers were related to functional test performance and respiratory muscle strength in older adults with COPD and sarcopenia. The participants included in this cross-sectional study were from both sexes and sixty years or older. Based on clinical assessment, participants were categorized in COPD (n = 43) and non-COPD (NCOPD) (n = 43) groups. They were also assessed for body composition and muscular mass by dual-energy X-ray absorptiometry, using the relative skeletal muscle index for the diagnosis of sarcopenia. A series of functional tests, including short physical performance battery (SPPB), 6-minute walking test (6MWT), maximal inspiratory and expiratory pressures (MIP and MEP), were carried out. Plasma levels of myokines (Irisin and BDNF), and soluble TNF receptors (sTNFR1 and sTNFR2) were determined by ELISA. In the multivariate analysis, 6MWD was associated with age, COPD-related sarcopenia and BDNF (R² = 0.29; f² = 0.41). SPPB score was associated with COPD-related sarcopenia and sTNFR1 (R² = 0.25; f² = 0.33). MIP value was associated with sex, COPD-related sarcopenia, sTNFR2 and Irisin (R² = 0.24; f² = 0.31). Finally, MEP value was associated with sex COPD-related sarcopenia (R² = 0.18; f² = 0.22). Plasma levels of myokines and inflammatory markers are related with functional and respiratory performance in older adults with COPD and sarcopenia.

Evaluation of Sarcopenia Using Biomarkers of the Neuromuscular Junction in Parkinson's Disease

Patients with Parkinson's disease (PD) present with an advanced form of age-related muscle loss or sarcopenia. However, the search for a biomarker to accurately predict muscle loss in PD remains elusive. We evaluated the biomarkers of neuromuscular junction (NMJ) stability, including c-terminal agrin fragment-22 (CAF22), brain-derived neurotrophic factor (BDNF), and glial cell line-derived neurotrophic factor (GDNF) as predictors of muscle wasting and physical capacity in PD. Male, 63-78 years patients of PD, were investigated for physical capacity, handgrip strength (HGS), and circulating biomarkers at the diagnosis and follow-up during rehabilitation 6 months apart. Patients with PD presented with elevated CAF22 and reduced BDNF and GDNF levels, which were partially restored to normal levels with rehabilitation. All three biomarkers showed significant dynamic associations with HGS and indexes of sarcopenia. Logistic regression revealed that the combination of biomarkers levels into a cumulative risk score enhanced the diagnostic accuracy of sarcopenia. In brief, measurements of plasma BDNF, GDNF, and CAF22 may be helpful in timely diagnosis and/or evaluation of sarcopenia.