View clinical trials related to Muscle Atrophy.
Filter by:Postoperative protocols for orthopedic procedures on the lower limb often require a period of immobilization to protect the surgical site. The consequence of this immobilization is muscle atrophy which can be severe, delaying a patient's return to activity and predisposing them to recovery complications or subsequent injury (1)(2). The current standard methods to assess lower limb muscle atrophy all have their respective limitations. Thigh circumference or isokinetic strength values are indirect measures of atrophy and can be inaccurate. Magnetic resonance imaging (MRI) of muscle cross-sectional area (CSA) is time-consuming and expensive. Computed tomography imaging of muscle CSA is expensive and exposes the patient to radiation (3). For these reasons, none of the current methods are ideal for regular use in the clinic. Musculoskeletal ultrasound is a promising measurement tool to assess muscle atrophy in postoperative patients. Ultrasound is non-invasive, cost-effective, does not involve radiation, and can give direct images of muscle size (4). Musculoskeletal ultrasound requires further research on its potential as an evaluation tool for postoperative lower limb orthopedic patients-specifically, whether ultrasound is a reliable and valid tool for quadriceps size measurements.
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.
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.
We want to test the hypothesis, that resistance training by the use of weigth cuffs on the angle can prevent loss or improve the strength of the quadriceps muscle in COPD patients admitted to hospital due to an exacerbation. The training is started at day one of admittance and the strength of the quadriceps is measured by a portable dynamometer.