Tracking the Plasma C-Terminal Agrin Fragment as a Biomarker of Neuromuscular Decline in 18- to 87-Year-Old Men.

OBJECTIVES: Plasma C-terminal agrin-fragment-22 (CAF22), a breakdown product of neuromuscular junction, is a potential biomarker of muscle loss. However, its levels from adolescence to octogenarians are unknown. METHODS: We evaluated young (18-34 years, n = 203), middle-aged (35-59 years, n = 163), and old men (60-87 years, n = 143) for CAF22, handgrip strength (HGS), appendicular skeletal-mass index (ASMI), and gait speed. RESULTS: We found an age-associated increase in CAF22 from young (100.9 ± 29 pmol) to middle-aged (128.3 ± 38.7 pmol) and older men (171.5 ± 35.5 pmol) (all p<0.05). This was accompanied by a gradual reduction in HGS (37.7 ± 6.1 kg, 30.2 ± 5.2 kg, and 26.6 ± 4.7 kg, for young, middle-aged, and old men, respectively), ASMI (8.02 ± 1.02 kg/m2, 7.65 ± 0.92 kg/m2, 6.87 ± 0.93 kg/m2, for young, middle-aged, and old men, respectively), and gait speed (1.29 ± 0.24 m/s, 1.05 ± 0.16 m/s, and 0.81 ± 0.13 m/s, for young, middle-aged, and old men, respectively). After adjustment for age, we found negative regressions of CAF22 with HGS (- 0.0574, p < 0.001) and gait speed (- 0.0162, p < 0.001) in the cumulative cohort. The receiver operating characteristics analysis revealed significant efficacy of plasma CAF22 in diagnosing muscle weakness (HGS < 27 kg) (middle-aged men; AUC = 0.731, 95% CI = 0.629-0.831, p < 0.001, Older men; AUC = 0.816, 95% CI = 0.761-0.833, p < 0.001), and low gait speed (0.8 m/s) (middle-aged men; AUC = 0.737, 95% CI = 0.602-0.871, p < 0.001, older men; AUC = 0.829, 95% CI = 0.772-0.886, p < 0.001), and a modest efficacy in diagnosing sarcopenia (middle-aged men; AUC = 0.701, 95% CI = 0.536-0.865, p = 0.032, older men; AUC = 0.822, 95% CI = 0.759-0.884, p < 0.001) in middle-aged and older men. CONCLUSION: Altogether, CAF22 increases with advancing age and may be a reliable marker of muscle weakness and low gait speed.

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.

Metformin Improves Sarcopenia-Related Quality of Life in Geriatric Adults: A Randomized Controlled Trial.

OBJECTIVES: Metformin protects against age-related muscle decline, termed sarcopenia. However, the effects on sarcopenia quality-of-life (SarQoL) are unknown. We investigated the effects of metformin on SarQoL and associated mechanisms in older adults. METHOD: This double-blind randomized, placebo-controlled trial included geriatric adult men, divided into non-sarcopenic controls (age = 72.2 ± 4.3 years, n = 52) and two groups of patients with sarcopenia randomized into placebo (age at baseline = 74.4 ± 5.7 years, n = 54) and metformin (age at baseline = 71.2 ± 3.9 years, n = 47) groups. Patients in the metformin group received 1.7 grams twice daily for four months. We evaluated SarQoL, handgrip strength (HGS), plasma zonulin, c-reactive protein (CRP), and 8-isoprostanes. RESULTS: Patients with sarcopenia had lower HGS and SarQoL than controls (both p <0.05). Metformin improved the HGS and the SarQoL domains related to physical and mental health, locomotion, and leisure activities, as well as cumulative SarQoL scores (all p <0.05). Metformin also prevented the decline in the SarQoL domains for functionality and fear. Among plasma biomarkers, metformin reduced the levels of zonulin, CRP, 8-isoprostanes, and creatine kinase. We also found a significant correlation of plasma zonulin with cumulative SarQoL in patients with sarcopenia taking metformin, suggesting a role for intestinal repair in improving SarQoL. Finally, metformin did not affect body composition and gait speed. CONCLUSION: Overall, metformin improved HGS and SarQoL by repairing intestinal leakage. Our data have clinical relevance for improving the quality of life in older adults with sarcopenia.

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.

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.

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.

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.

Elevated plasma zonulin and CAF22 are correlated with sarcopenia and functional dependency at various stages of Alzheimer's diseases.

Age-related muscle decline, termed sarcopenia, is closely linked to dementia; however, its causative factors in patients with Alzheimer's disease (AD) are poorly characterized. We investigated the plasma biomarkers of increased intestinal permeability (zonulin) and neuromuscular junction (NMJ) disruption (c-terminal agrin fragment-22; CAF22), in healthy controls (n = 53) and patients with early, mild, and moderate AD (n = 46-56/group). We also evaluated the body composition, handgrip strength (HGS), and short physical performance battery (SPPB) as markers of sarcopenia and functional capacity, respectively. Patients with AD had elevated plasma zonulin and CAF22, along with reduced HGS, gait speed, and SPPB scores than controls (all p < 0.05). Plasma zonulin and CAF22 exhibited robust negative associations with HGS and relatively weak but statistically significant associations with gait speed and ASMI (all p < 0.05). Lower SPPB scores were associated with elevated plasma zonulin and CAF22 levels. Patients with moderate AD had higher plasma zonulin, CAF22, prevalence of sarcopenia, and lower HGS and SPPB scores than patients with early AD. These patients also presented with upregulation of markers of inflammation and oxidative stress. Altogether, AD was associated with an advanced sarcopenia phenotype, and plasma zonulin and CAF22 may be useful in assessing sarcopenia and functional dependency in AD patients.

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.