Age-related susceptibility to muscle damage following mechanotherapy in rats recovering from disuse atrophy

Author(s):  
Zachary R Hettinger ◽  
Kyoko Hamagata ◽  
Amy L Confides ◽  
Marcus M Lawrence ◽  
Benjamin F Miller ◽  
...  

Abstract The inability to fully recover lost muscle mass following periods of disuse atrophy predisposes older adults to lost independence and poor quality of life. We have previously shown that mechanotherapy at a moderate load (4.5 N) enhances muscle mass recovery following atrophy in adult, but not older adult rats. We propose that elevated transverse stiffness in aged muscle inhibits the growth response to mechanotherapy and hypothesize that a higher load (7.6 N) will overcome this resistance to mechanical stimuli. F344/BN adult and older adult male rats underwent 14-days of hindlimb suspension, followed by 7-days of recovery with (RE+M) or without (RE) mechanotherapy at 7.6 N on gastrocnemius muscle. The 7.6 N load was determined by measuring transverse passive stiffness and linearly scaling up from 4.5 N. No differences in protein turnover or mean fiber cross sectional area were observed between RE and RE+M for older adult rats or adult rats at 7.6 N. However, there was a higher number of small muscle fibers present in older adult, but not adult rats, which was explained by a 16-fold increase in the frequency of small fibers expressing embryonic myosin heavy chain. Elevated central nucleation, satellite cell abundance, and dystrophin -/laminin + fibers were present in older adult rats only following 7.6 N, while 4.5 N did not induce damage at either age. We conclude that age is an important variable when considering load used during mechanotherapy and age-related transverse stiffness may predispose older adults to damage during the recovery period following disuse atrophy.

2020 ◽  
Vol 28 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Katie A. Conway ◽  
Jason R. Franz

The authors elucidated functional limitations in older adult gait by increasing horizontal impeding forces and walking speed to their maximums compared with dynamometry and with data from their young counterparts. Specifically, the authors investigated which determinants of push-off intensity represent genuine functionally limiting impairments in older adult gait versus biomechanical changes that do not directly limit walking performance. They found that older adults walked at their preferred speed with hallmark deficits in push-off intensity. These subjects were fully capable of overcoming deficits in propulsive ground reaction force, trailing limb positive work, trailing leg and hip extension, and ankle power generation when the propulsive demands of walking were increased to maximum. Of the outcomes tested, age-related deficits in ankle moment emerged as the lone genuine functionally limiting impairment in older adults. Distinguishing genuine functional limitations from age-related differences masquerading as limitations represents a critical step toward the development and prescription of effective interventions.


Geriatrics ◽  
2018 ◽  
Vol 3 (4) ◽  
pp. 66 ◽  
Author(s):  
Marie Jardine ◽  
Anna Miles ◽  
Jacqui Allen

New-onset swallowing difficulties in older patients during unrelated hospital admissions are well recognized and may result in prolonged hospital stay and increased morbidity. Presbyphagia denotes age-related swallowing changes which do not necessarily result in pathological effects. The trajectory from presbyphagia to dysphagia is not well understood. This retrospective observational study compared quantitative videofluoroscopic measures in hospitalized older adults aged 70–100 years, reporting new dysphagia symptoms during admission (n = 52), to healthy asymptomatic older (n = 56) and younger adults (n = 43). Significant physiological differences seen in hospitalized older adults but not healthy adults, were elevated pharyngeal area (p < 0.001) and pharyngeal constriction ratio (p < 0.001). Significantly increased penetration (p < 0.001), aspiration (p < 0.001) and pharyngeal residue (p < 0.001) were also observed in the hospitalized older cohort. Reasons for onset of new swallow problems during hospitalization are likely multifactorial and complex. Alongside multimorbidity and polypharmacy, a combination of factors during hospitalization, such as fatigue, low levels of alertness, delirium, reduced respiratory support and disuse atrophy, may tip the balance of age-related swallowing adaptations and compensation toward dysfunctional swallowing. To optimize swallowing assessment and management for our aging population, care must be taken not to oversimplify dysphagia complaints as a characteristic of aging.


BMJ Open ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. e027728 ◽  
Author(s):  
Siobhan Leahy ◽  
Marica Cassarino ◽  
Matthew DL O' Connell ◽  
Liam Glynn ◽  
Rose Galvin

IntroductionTwo major global health challenges are the rapidly ageing population and the high prevalence of obesity in all age groups. Older adults are also susceptible to age-related loss of muscle strength, termed dynapaenia. The co-occurrence of both obesity and dynapaenia, termed dynapaenic obesity (DO), has been associated with poorer health outcomes and increased healthcare usage compared with either state alone. The purpose of this systematic review is to quantify the prevalence and incidence of DO in older adult populations, and to explore the association between DO and health outcomes, specifically chronic disease and multimorbidity, functional disability and healthcare usage.Methods and analysisUsing the Meta-analyses Of Observational Studies in Epidemiology guidelines, we will conduct a systematic review of cross-sectional and longitudinal observational studies of older adults, which include measures of DO and specified outcomes. Detailed literature searches of will be conducted using six electronic databases: Excerpta Medica dataBASE (EMBASE), PubMed, MEDLINE, SCOPUS, ScienceDirect and Cumulative Index of Nursing and Allied Health Complete (CINAHL), including articles published from database inception until Febuary 2019. The reference lists of included articles will also be searched. Two independent reviewers will undertake a three-step screening and review process using the Population, Risk Factor, Outcome framework to define eligibility. The Newcastle Ottawa Scale for non-randomised studies will be used to assess risk of bias and to rate study quality. The findings will be synthesised in a narrative summary, and a meta-analysis will be conducted where appropriate.Ethics and disseminationEthical approval is not required for this systematic review. Findings from this research will be submitted for peer-reviewed publication in academic journals, and presented at relevant academic conferences.PROSPERO registration numberCRD42018112471.


1998 ◽  
Vol 85 (5) ◽  
pp. 1903-1908 ◽  
Author(s):  
Ronald R. Gomes ◽  
Frank W. Booth

We examined the age-related association in skeletal muscle between atrophy and expression of mRNAs encoding both the γ-subunit of the nicotinic acetylcholine receptor (AChR), and myogenin, a transcription factor that upregulates expression of the γ-subunit promoter. Gastrocnemius and biceps brachii muscles were collected from young (2-mo-old), adult (18-mo-old), and old (31-mo-old) Fischer 344/Brown Norway F1 generation cross male rats. In the gastrocnemius muscles of old vs. young and adult rats, lower muscle mass was accompanied by significantly elevated AChR γ-subunit and myogenin mRNA levels. In contrast, the biceps brachii muscle exhibited neither atrophy nor as drastic a change in AChR γ-subunit and myogenin mRNA levels with age. Expression of the AChR ε-subunit mRNA did not change with age in either gastrocnemius or biceps brachii muscles. Thus changes in skeletal muscle AChR γ-subunit and myogenin mRNA levels may be more related to atrophy than to chronological age in old rats.


2005 ◽  
Vol 98 (2) ◽  
pp. 557-564 ◽  
Author(s):  
David M. Thomson ◽  
Scott E. Gordon

Skeletal muscle mass declines with age, as does the potential for overload-induced fast-twitch skeletal muscle hypertrophy. Because 5′-AMP-activated protein kinase (AMPK) activity is thought to inhibit skeletal muscle protein synthesis and may therefore modulate muscle mass and hypertrophy, the purpose of this investigation was to examine AMPK phosphorylation status (a marker of AMPK activity) and its potential association with the attenuated overload-induced hypertrophy observed in aged skeletal muscle. One-week overload of fast-twitch plantaris and slow-twitch soleus muscles was achieved in young adult (8 mo; n = 7) and old (30 mo; n = 7) Fischer344 × Brown Norway male rats via unilateral gastrocnemius ablation. Significant ( P ≤ 0.05) age-related atrophy (as measured by total protein content) was noted in plantaris and soleus control (sham-operated) muscles. In fast-twitch plantaris muscles, percent hypertrophy with overload was significantly attenuated with age, whereas AMPK phosphorylation status as determined by Western blotting [phospho-AMPK (Thr172)/total AMPK] was significantly elevated with age (regardless of loading status). There was also a main effect of loading on AMPK phosphorylation status in plantaris muscles (overload > control). Moreover, a strong and significant negative correlation ( r = −0.82) was observed between AMPK phosphorylation status and percent hypertrophy in the overloaded plantaris muscles of all animals. In contrast to the plantaris, overload-induced hypertrophy of the slow-twitch soleus muscle was similar between ages, and AMPK phosphorylation in this muscle was also unaffected by age or overload. These data support the possibility that an age-related elevation in AMPK phosphorylation may partly contribute to the attenuated hypertrophic response observed with age in overloaded fast-twitch plantaris muscle.


2000 ◽  
Vol 167 (3) ◽  
pp. 417-428 ◽  
Author(s):  
R Lalani ◽  
S Bhasin ◽  
F Byhower ◽  
R Tarnuzzer ◽  
M Grant ◽  
...  

The mechanism of the loss of skeletal muscle mass that occurs during spaceflight is not well understood. Myostatin has been proposed as a negative modulator of muscle mass, and IGF-I and IGF-II are known positive regulators of muscle differentiation and growth. We investigated whether muscle loss associated with spaceflight is accompanied by increased levels of myostatin and a reduction in IGF-I and -II levels in the muscle, and whether these changes correlate with an increase in muscle proteolysis and apoptosis. Twelve male adult rats sent on the 17-day NASA STS-90 NeuroLab space flight were divided upon return to earth into two groups, and killed either 1 day later (R1) or after 13 days of acclimatization (R13). Ground-based control rats were maintained for the same periods in either vivarium (R3 and R15, respectively), or flight-simulated cages (R5 and R17, respectively). RNA and protein were isolated from the tibialis anterior, biceps femoris, quadriceps, and gastrocnemius muscles. Myostatin, IGF-I, IGF-II and proteasome 2c mRNA concentrations were determined by reverse transcription/PCR; myostatin and ubiquitin mRNA were also measured by Northern blot analysis; myostatin protein was estimated by immunohistochemistry; the apoptotic index and the release of 3-methylhistidine were determined respectively by the TUNEL assay and by HPLC. Muscle weights were 19-24% lower in the R1 rats compared with the control R3 and R5 rats, but were not significantly different after the recovery period. The myostatin/beta-actin mRNA ratios (means+/-s.e.m. ) were higher in the muscles of the R1 rats compared with the control R5 rats: 5.0-fold in tibialis (5.35 +/- 1.85 vs 1.07 +/- 0.26), 3.0-fold in biceps (2.46+/-0.70 vs 0.81 +/- 0.04), 1.9-fold in quadriceps (7.84 +/- 1.73 vs 4.08 +/- 0.52), and 2.2-fold in gastrocnemius (0.99 +/- 0.35 vs 0.44 +/- 0.17). These values also normalized upon acclimatization. Our antibody against a myostatin peptide was validated by detection of the recombinant human myostatin protein on Western blots, which also showed that myostatin immunostaining was increased in muscle sections from R1 rats, compared with control R3 rats, and normalized upon acclimatization. In contrast, IGF-II mRNA concentrations in the muscles from R1 rats were 64-89% lower than those in R3 animals. With the exception of the gastrocnemius, IGF-II was also decreased in R5 animals maintained in flight-simulated cages, and normalized upon acclimatization. The intramuscular IGF-I mRNA levels were not significantly different between the spaceflight rats and the controls. No increase was found in the proteolysis markers 3-methyl histidine, ubiquitin mRNA, and proteasome 2C mRNA. In conclusion, the loss of skeletal muscle mass that occurs during spaceflight is associated with increased myostatin mRNA and protein levels in the skeletal muscle, and a decrease in IGF-II mRNA levels. These alterations are normalized upon restoration of normal gravity and caging conditions. These data suggest that reciprocal changes in the expression of myostatin and IGF-II may contribute to the multifactorial pathophysiology of muscle atrophy that occurs during spaceflight.


2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
M. E. Levine ◽  
E. M. Crimmins

This study examined the influence of insulin resistance and inflammation on the association between body composition and cognitive performance in older adults, aged 60–69 and aged 70 and older. Subjects included 1127 adults from NHANES 1999–2002. Body composition was categorized based on measurements of muscle mass and waist circumference as sarcopenic nonobese, nonsarcopenic obese, sarcopenic obese, and normal. Using OLS regression models, our findings suggest body composition is not associated with cognitive functioning in adults ages 60–69; however, for adults aged 70 and over, sarcopenia and obesity, either independently or concurrently, were associated with worse cognitive functioning relative to non-sarcopenic non-obese older adults. Furthermore, insulin resistance accounted for a significant proportion of the relationship between cognitive performance and obesity, with or without sarcopenia. Additionally, although high CRP was significantly associated with poorer cognitive functioning in adults ages 60–69, it did not influence the association between body composition and cognitive performance. This study provides evidence that age-related physiological maladaptations, such as metabolic deregulation, which are associated with abdominal fat, may simultaneously contribute to lower cognition and muscle mass, reflecting a degradation of multiple physiological systems.


2021 ◽  
Author(s):  
Charles M. Lepkowsky

Telehealth has become increasingly prominent during the COVID-19 pandemic, highlighting limitations in access to care for older adults less fluent in information technology (IT). Although the 20 percent disparity in IT use between younger and older adult cohorts remains unchanged over several decades, insurers, institutional and independent providers of health care have made increasing use of IT for patient communication. Data demonstrate an age-related decline in the frequency of IT use for accessing health care. Restrictions on reimbursement for the use of the telephone for accessing health care during the COVID-19 pandemic are discussed as a barrier to access to care. Recommendations are made for assessment of media most available to older adults for accessing health care, as well as providing funding to support increased access to care.


2021 ◽  
Vol 9 ◽  
Author(s):  
Yiwen Zhang ◽  
Xiao-Dan Wang ◽  
Yehua Song ◽  
Ruiqiang Peng ◽  
Ting Tang ◽  
...  

Background: Frequent/urgent urination is an event of multifactorial origin where involuntary leakage of urine occurs. Epidemiological study of this condition is of high importance due to its negative impact on the psychological, physical, and social well-being of the victims.Objective: This cross-sectional study aimed to investigate the prevalence of frequent/urgent urination in older adults in China.Method: In this study, a face-to-face questionnaire survey was conducted between April 2019 and August 2019 among 4,796 older adult populations in the communities of Tianjin jizhou and Xiamen jimei of China. Descriptive analysis, univariate regression, and all statistics were conducted in IBM SPSS v22. The count data were analyzed by chi-square test. P &lt; 0.05 was considered statistically significant.Results: In the total investigated population, the prevalence of frequent or urgent urination was found in 1,164 patients (24.3%) where 31.7% (664/2,097) were male patients and 18.7% (500/2,699) were female patients, having a male-to-female ratio of 1.7:1. The prevalence was higher in the 70- to 84-year-old group (men: 33.3–34.8%, women 19.5–20.8%), whereas it was relatively low in the 65- to 69-year-old group and in older adults over 85 years of age (men 28.8, 30.3%, women 16.7, 18.5%, respectively). In terms of the course of the disease, among the population aged 65 years and above, 17.3% men and 9.9% women had frequent urination/urgency lasting for 1–4 years; 5–9 years in about 4.5% population (7.4% men and 4.2% women); 10–19 years in 4.9% men and 2.3% women; and more than 20 years duration in 1.6% men and 1.9% women. On the severity scale, mild frequent/urgent urination was observed in 24.6% of men and 15.4% women of Chinese older adults. Moderate cases were observed in 6.3% of men and 2.9% of women, whereas severe cases were found in 0.8% men and 0.2% women. Benign prostatic hyperplasia (BPH)/hypertrophy was the main risk factor for frequent/urgent urination in Chinese older adult men (P &lt; 0.001). Obesity, hypertension, diabetes, heart disease, anxiety, depression, constipation, and brain injury were the other risk factors for frequent/urgent urination in Chinese older adult men and women. The results of this survey showed that smoking or drinking habits did not increase the prevalence of frequent/urgent urination in Chinese older adults.Conclusions: According to the results of this survey, the prevalence rate of frequent/urgent urination is high, and the course of the disease is long in Chinese older adults. BPH and depression, anxiety, and age-related chronic diseases increase the risk of frequent/urgent urination in Chinese older adults.


2021 ◽  
Vol 3 ◽  
Author(s):  
Dongyual Yoo ◽  
Junmo An ◽  
Kap-Ho Seo ◽  
Beom-Chan Lee

Age-related changes cause more fall-related injuries and impede the recoveries by older adults compared to younger adults. This study assessed the lower limb joint moments and muscle responses to split-belt treadmill perturbations in two groups (14 healthy young group [23.36 ± 2.90 years] and 14 healthy older group [70.93 ± 4.36 years]) who performed two trials of unexpected split-belt treadmill perturbations while walking on a programmable split-belt treadmill. A motion capture system quantified the lower limb joint moments, and a wireless electromyography system recorded the lower limb muscle responses. The compensatory limb's (i.e., the tripped limb's contralateral side) joint moments and muscle responses were computed during the pre-perturbation period (the five gait cycles before the onset of a split-belt treadmill perturbation) and the recovery period (from the split-belt treadmill perturbation to the baseline gait relying on the ground reaction forces' profile). Joint moments were assessed by maximum joint moments, and muscle responses were quantified by the normalization (%) and co-contraction index (CCI). Joint moments and muscle responses of the compensatory limb during the recovery period were significantly higher for the YG than the OG, and joint moments (e.g., knee flexion and extension and hip flexion moments) and muscle responses during the recovery period were higher compared to the pre-perturbation period for both groups. For CCI, the older group showed significantly higher co-contraction for biceps femoris/rectus femoris muscles than the young group during the recovery period. For both groups, co-contraction for biceps femoris/rectus femoris muscles was higher during the pre-perturbation period than the recovery period. The study confirmed that older adults compensated for muscle weakness by using lower joint moments and muscle activations and increasing muscle co-contractions to recover balance after split-belt treadmill perturbations. A better understanding of the recovery mechanisms of older adults who train on fall-inducing systems could improve therapeutic regimens.


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