Muscle mass, quality, and the menopause: sex-specific strategies to mitigate sarcopenia in aging populations

随着年龄的增长，我们的肌肉变得越来越小，越来越弱（肌肉减少症），这可能会使我们更难完成日常活动，并增加我们对医疗保健系统的依赖。英国人口老龄化日益严重，因此，肌肉减少症是一个主要的医疗保健问题（例如，2016年英国医疗保健系统的估计成本为25亿英镑）。迫切需要制定预防肌肉减少症的策略。然而，这些策略需要有针对性，有证据表明老年男性和女性患肌肉减少症的方式不同。例如，与男性相比，女性肌肉减少症发病更早，导致更严重的身体残疾。随着年龄的增长，潜在的性别差异尚不清楚，但女性肌肉减少症的早期流行与更年期相吻合。更年期是性激素环境的变化，是正常女性衰老的一部分，与身体成分的变化有关，包括肌肉损失和体脂增加。身体脂肪的增加可能会进入肌肉，进一步加速肌肉力量的丧失和健康状况的恶化。人们对身体成分的这些变化是如何发生的还缺乏了解。然而，要使肌肉变小，我们移除肌肉蛋白质的速度和生成新肌肉蛋白质的速度之间一定存在不平衡。我们最近开发了先进的生物化学技术来测量我们制造和去除肌肉蛋白质的速度。通过将这些技术应用于绝经前和绝经后妇女，我们将能够第一次更好地了解衰老过程中肌肉蛋白质的平衡。通过将这些技术与磁共振成像（MRI）相结合，我们将开发出新的方法来定位新脂肪在体内沉积的位置和速度。综合起来，这些方法将为如何最好地针对女性肌肉减少症的未来干预提供重要的见解。抗阻运动疗法（RET）目前提供了最有效的策略，以促进肌肉质量和力量的老化。然而，与年轻女性相比，老年女性对抗阻运动的反应迟钝。我们将测量更年期是否会影响新肌肉蛋白在运动后的生成速度，并且，使用我们的核磁共振成像技术，我们将监测RET是否会改变体内脂肪沉积的速度。总之，这些措施将确定RET在减缓绝经后妇女肌肉减少症和改善身体成分方面的有效性。利用我们的研究结果，我们将创建基于证据的资源和信息，并通过与英国体育积极合作伙伴关系（莱斯特郡和诺茨体育共同活跃）、诺丁汉大学和莱斯特大学的体育运动医学系、拉夫堡的国家体育和运动医学中心以及全国医生“运动医学”网站的现有联系，将这些建议实施到更年期干预计划中。莱斯特综合医院的运动医学诊所，以及莱斯特和诺丁汉的更年期诊所。

As we grow older, our muscles become smaller and weaker (sarcopenia), which can make it more difficult to complete daily activities and can increase our reliance on healthcare systems. The UK has a growing ageing population, and, therefore, sarcopenia represents a major healthcare concern, (for example, its estimated cost to the UK healthcare system in 2016 was £2.5 billion). There is an urgent need to develop strategies to prevent sarcopenia. However, these strategies need to be targeted, with evidence suggesting that older men and women develop sarcopenia differently. For instance, sarcopenia develops earlier in women, resulting in greater levels of physical disability compared with men. The underlying sex differences with ageing are unclear, yet the earlier prevalence of sarcopenia in women coincides with the menopause. The menopause is a change in the sex hormone environment that is a part of normal female ageing and is associated with changes in body composition including muscle loss and increased body fat. This increase in body fat can become located within muscle, further accelerating the loss of muscle strength and poor health. There is a lack of understanding of how these changes in body composition occur. However, for muscle to decrease in size, there must be an imbalance between how quickly we remove muscle proteins and how quickly we make new muscle proteins. We have recently developed advanced biochemistry techniques to measure how quickly we make and remove muscle proteins. By applying these techniques to pre- and post-menopausal women, we will be able to better understand muscle protein balance during ageing for the first time. By combining these techniques with magnetic resonance imaging (MRI), we will develop new methods to locate where, and how quickly, new fat is deposited in the body. Combined, these approaches will provide vital insights on how best to target future interventions against sarcopenia in women. Resistance exercise therapy (RET) currently offers the most effective strategy to promote muscle mass and strength in ageing. However, responses to resistance exercise are blunted in older women compared to younger women. We will measure whether the menopause has an impact on how quickly new muscle proteins are made in response to exercise, and, using our MRI imaging techniques, we will monitor whether RET alters the rate of fat deposition in the body. Together, these measures will determine the effectiveness of RET at slowing sarcopenia and improving body composition in post-menopausal women. Using our results, we will create evidence-based resources and information, and implement these recommendations into menopause intervention programmes through existing connections with Sport England Active Partnerships (Active Together in Leicestershire and Sport Notts), Sports Exercise Medicine departments at the Universities of Nottingham and Leicester and the National Centre for Sport and Exercise Medicine in Loughborough, as well as the national "Moving Medicine" website for doctors, the Exercise Medicine clinic at Leicester General Hospital, and menopause clinics in Leicester and Nottingham.