View clinical trials related to Muscle Atrophy.
Filter by:The maintenance of skeletal muscle mass and function is critical for healthy aging. Muscle loss with disuse, termed muscle disuse muscle atrophy, leads to impaired functional capacity, the onset of insulin resistance, as well as a heightened risk for morbidity and mortality. With advancing age there is a chronic wasting of muscle. This is especially true in women, where rapid rates of decline in muscle mass and greater anabolic resistance are experienced around the time of menopause, despite higher protein synthesis rates. As women have a longer life expectancy, they are particularly venerable to age-related frailty and morbidity. Skeletal muscle protein turnover serves to maintain the optimal function of proteins and also provides plasticity of the tissue during altered demands such as during increased loading or unloading of the muscle. Reduced periods of physical activity also have a similar, albeit milder, impact on skeletal muscle and most, people will likely experience multiple bouts of skeletal muscle disuse during their lifetime from which some, particularly older adult women, will fail to fully recover. Thus, muscle disuse atrophy is a significant and continuing problem as reclamation of lost muscle mass, strength/function, and potentially metabolic health (particularly insulin-induced glucose disposal), following disuse is oftentimes incomplete and may be further exacerbated after menopause. Previous evidence has demonstrated that in the loss of muscle mass is less pronounced in post-menopausal women when receiving hormone replacement therapy. Skeletal muscle has estrogen-β-receptors on the cell membrane, in the cytoplasm and on the nuclear membrane, and therefore a direct mechanistic link between low estrogen levels and a decrease MPS. Interestingly, despite higher rates of protein synthesis, older women still lose muscle mass with advancing age. It has been suggested that the negative muscle protein balance is due to an enhanced rate of MPB. Insulin is a potent inhibitor of MPB and estrogen has been shown to enhance insulin sensitivity in skeletal muscle. However, to our knowledge, no study has examined the efficacy of estrogen supplementation to attenuate the losses of skeletal muscle mass and function during a period of disuse. The findings of this investigation may yield critical data for those who wish to combat skeletal muscle disuse atrophy, particularly after menopause.
This study will examine the influence of n3 PUFA supplementation on the rate of muscle atrophy in women undergoing 2 weeks of unilateral limb immobilization. Assessments in skeletal muscle strength and skeletal muscle volume will also me made before, after and in recovery from immobilization.
This study evaluates the effect of increase in testosterone levels in older males and the effects of decrease in testosterone levels in young males on muscle protein synthesis.
It is well known that periods of weight training lead to increases in skeletal muscle size and strength. In contrast, periods of inactivity such as bed rest or immobilization result in losses of skeletal muscle size and strength. However, individuals experience variable magnitudes of muscle size change in response to changes in mechanical tension, such that certain individuals experience large changes in muscle mass whereas others do not. What is not currently known, and will be the primary goal of the present investigation, is to determine whether individuals who gain the most muscle mass with exercise training also lose the most muscle when they are immobilized. The investigators hypothesize that individuals who gain the most muscle with training will also lose the most with immobilization.
No previous studies have compared the association between muscle thickness (MT) and muscle cross-sectional area (CSA) in healthy volunteers. The main aim of this study is to investigate the validity of ultrasound in assessing the muscle thickness of hamstrings muscle. Study design: A cross-sectional-validity study. Setting: University Participants: X football players of an amateur football team (X healthy volunteers and X patients with a previous hamstring injury).
Acute muscle wasting occurs early and rapidly during the first week of critical illness and contributes substantially to weakness acquired in the ICU. Muscle wasting and subsequent weakness is associated with delayed liberation from mechanical ventilation, prolonged hospital length of stay, long-term functional disability, and worse quality of life. Moreover, low muscle volume as well as ICU-acquired weakness increases the risk of mortality in critically ill patients. Although several factors likely accelerate skeletal muscle wasting during critical illness (e.g., immobility, inflammation, multi-organ failure), the understanding of the underlying mechanisms remains limited and is reflected in the lack of effective interventions to prevent the loss of muscle mass in ICU patients. To-date, there is no known safe and effective pharmacological or nutritional intervention to attenuate the acute loss of muscle mass in ICU patients. Leucine is an amino acid widely regarded for its anabolic effects on muscle metabolism. However, the concentrations required to maximize its anti-proteolytic effects are far greater than the concentrations required to maximally stimulate protein synthesis. This has resulted in the search for leucine metabolites that may also be potent mediators of anabolic processes in skeletal muscle; one such compound is β-hydroxy-β-methylbutyrate (HMB). HMB is thought to primarily facilitate protein synthesis through stimulation of mammalian target of rapamycin (mTOR), a protein kinase responsive to mechanical, hormonal, and nutritional stimuli that plays a central role in the control of cell growth. Randomized, controlled trials to assess the effect of HMB supplementation on clinical outcomes in patients with chronic diseases are limited, and even fewer studies have assessed its effects on skeletal muscle metabolism during critical illness. Furthermore, despite compelling preclinical evidence, the exact mechanisms underlying the effect of HMB supplementation during acute catabolic stress in humans is not well defined. Therefore, the investigators goal is to study the impact of early HMB supplementation on skeletal muscle mass in ICU patients and to explore the mechanisms by which HMB may exert its effects on skeletal muscle metabolism during critical illness.
This study aims to determine whether vitamin D3 supplementation is any more effective in improving musculoskeletal function when combined with exercise training compared with exercise training alone.
A decrease in muscle mass can have a profound impact on quality of life, as it can lead to decreased strength, insulin resistance, lower basal metabolic rate and obesity. With this study we investigate whether ingesting leucine or getting a ND injection will reduce the loss of muscle mass and strength.
Chronic Obstructive Pulmonary Disease (COPD) is the most common pulmonary disease, responsible for considerable morbidity and mortality and is the third leading cause of death worldwide. As well as its consequences in the lungs, COPD is well recognized to be associated with a range of important systemic consequences and co-morbidities. Interestingly, skeletal muscle dysfunction is noted in both early and advanced disease, suggesting its origins may not be wholly pulmonary. Treatment strategies targeting lung function are, unfortunately, of limited value. Given the burden of disease, it is becoming increasingly important that investigative and therapeutic work now focuses on other systemic characteristics and sequelae which define the disease phenotype. This is a randomized controlled trial of the effect of 14 days of voluntary reduced activity on muscle mass, muscle strength, body composition, and atrophy signalling in patients with COPD and age-matched controls. The primary hypothesis upon which this study is based is that a short reduction in ambulation will induce a transient reduction in quadriceps muscle mass, quadriceps strength and physical performance in patients with COPD compared to matched COPD patients whose mobility has not been restricted. The secondary hypothesis is that the magnitude of the above changes will be greater in physically inactive COPD patients compared to physically inactive age-matched controls. The overall aim of this research is to use an in vivo human model of 14 days of voluntary reduced physical activity to test the above hypotheses. If the model proves feasible, this will allow for earlier proof of concept studies of novel therapeutic agents.
As a function of the growing population of older adults, an estimated 3.48 million total knee arthroplasty (TKA) procedures will be performed annually in the U.S. by 2030. Despite the near-universal success of this surgery in mitigating chronic knee pain, TKA is not successful in restoring long-term physical function in older adults, primarily because of quadriceps muscle atrophy, which explains 77% of the strength deficits. Overall, strength and functional mobility in TKA patients is 30-50% below age-matched healthy controls. Functional tasks such as stair-climbing remain a clinical problem for 75% of patients following TKA. Muscle atrophy occurs in both operative and non-operative legs, and is essentially permanent for older patients because of their impaired ability to increase muscle mass. The purpose of this clinical research is to determine the effects of essential amino acid (EAA) supplementation on muscle mass, strength, and functional mobility following TKA in older adults. Based on strong preliminary data, the investigators hypothesize that twice-daily ingestion of 23 g of EAA for 1 wk before through 6 wk after TKA will increase basal rates of muscle protein synthesis via inactivation of catabolic signaling, and up-regulation of anabolic and cyto-protective proteins. The investigators further hypothesize that short-term atrophy prevention and accelerated return of functional mobility will lead to longer-term structural and functional adaptations, and improved quality of life in older TKA patients vs. Placebo. Identifying the mechanisms up-regulated by EAA treatment that preserve muscle volume and mobility will have a major impact on rehabilitation science. This study will accomplish two specific aims: (1) determine if EAA elevates basal rates of muscle protein synthesis by up-regulating anabolic pathways and cyto-protective proteins, and inactivating catabolic pathways in the short term vs. Placebo and (2) determine if short-term prevention of atrophy, weakness, and functional mobility leads to positive changes in muscle cell structure and function, and improved quality of life in the longer term vs. Placebo. This work is significant because it advances knowledge of the molecular and cellular changes occurring during muscle atrophy (Placebo) and atrophy prevention (EAA) in a clinical setting using a treatment that is broadly applicable, is well tolerated, and can be implemented immediately.