Anorexia, sarcopenia, and aging.

Food intake declines throughout the life span. This physiologic anorexia of aging is caused in part by alterations of stomach-fundus compliance and release and activity of cholecystokinin. In addition, the decline in testosterone in males results in elevated leptin levels that increase the anorexia. There is also evidence that cytokines play a role in the pathogenesis of anorexia and sarcopenia, thus accelerating the development of frailty in older persons. Numerous treatable causes of anorexia and weight loss exist. Depression is the most commonly diagnosed cause of pathologic weight loss in older persons.     

Protein and exercise in the prevention of sarcopenia and aging

Aging is associated with a progressive decline in skeletal muscle mass and strength. The decline, known as sarcopenia, could lead to physical disability, poor quality of life, and death. In addition, the older population usually experiences age-related muscle changes that affect muscle mass, muscular strength, and functional abilities. The purpose of this review is to describe the role of protein and exercise in slowing the progression of sarcopenia. It will also discuss whether age-related changes can be attenuated by dietary protein and exercise in the older population. This review will also cover one of the possible mechanisms of how dietary protein and exercise are involved in sarcopenia prevention, as well as the available measurement tools. Based on the findings of this review, the adequate amount of protein required for older men and women needs to be revised and likely be higher. Moreover, studies are required to explore some inconclusive findings concerning sarcopenia in the older population. Further research is required to investigate the following: (1) the safety and effectiveness concerning the consumption of 1.4 g of protein/kg of body weight (or more) in this vulnerable population; (2) the effectiveness of amino acid supplementation in reducing progression of sarcopenia over time through longitudinal studies; (3) the preferred source and timing of protein for the older population to maintain muscular strength and attenuate sarcopenia; (4) exercise interventions, especially those of longer duration, in the attenuation of sarcopenia; (5) other types of exercise and their effects on age-related muscle changes; (6) the mechanism of how protein and exercise prevent muscle loss with aging; and (7) determine the best method to diagnose sarcopenia.     

Role of dietary protein in the sarcopenia of aging

Sarcopenia is a complex, multifactorial process facilitated by a combination of factors including the adoption of a more sedentary lifestyle and a less than optimal diet. Increasing evidence points to a blunted anabolic response after a mixed nutrient meal as a likely explanation for chronic age-related muscle loss. There is currently insufficient longer-term research with defined health outcomes to specify an optimal value for protein ingestion in elderly individuals. However, there is general agreement that moderately increasing daily protein intake beyond 0.8 g x kg(-1) x d(-1) may enhance muscle protein anabolism and provide a means of reducing the progressive loss of muscle mass with age. The beneficial effects of resistance exercise in aging populations are unequivocal. However, research has not identified a synergistic effect of protein supplementation and resistance exercise in aging populations. There is little evidence that links high protein intakes to increased risk for impaired kidney function in healthy individuals. However, renal function decreases with age, and high protein intake is contraindicated in individuals with renal disease. Assessment of renal function is recommended for older individuals before they adopt a higher-protein diet.     

Loss of skeletal muscle mass in aging: examining the relationship of starvation, sarcopenia and cachexia

A loss of body weight or skeletal muscle mass is common in older persons and is a harbinger of poor outcome. Involuntary weight loss can be categorized into three primary etiologies of starvation, sarcopenia, and cachexia. Starvation results in a loss of body fat and non-fat mass due to inadequate intake of protein and energy. Sarcopenia is associated with a reduction in muscle mass and strength occurring with normal aging, associated with a reduction in motor unit number and atrophy of muscle fibers, especially the type IIa fibers. The loss of muscle mass with aging is clinically important because it leads to diminished strength and exercise capacity. Cachexia is widely recognized as severe wasting accompanying disease states such as cancer or immunodeficiency disease, but does not have a universally accepted definition. The key clinical question is whether these changes in body composition are distinct entities or represent an interdependent continuum. The importance of defining the distinction lies in developing a targeted therapeutic approach to skeletal muscle loss and muscle strength in older persons. Failure to distinguish among these causes of skeletal muscle loss often results in frustration over the clinical response to therapeutic interventions.     

The relationship between health-promoting lifestyles and depression in the elderly: roles of aging perceptions and social support

Quality of Life Research - At present, it is not clear about the influence of health-promoting lifestyle, aging perceptions, social support, and other psychosocial factors on elderly depression....     

The many roles of apoptosis in immunity as modified by aging and nutritional status

Apoptosis plays a vital role in the elimination of anti-self clones, down regulation of immune responses and the killing of virally infected and malignant cells. There is ample evidence that as we age the immune system not only becomes less potent, but dysregulated which includes apoptotic dependent functions. Reductions in the production of naive T and B-cells, reduced cytolytic killing capacity, accumulation of larger numbers of malignant cells, enhanced inflammatory responses, etc., in the aged suggest that apoptosis is dysregulated. Changes in nutritional status can also alter apoptosis. A short period of zinc deficiency (ZD) in young adult mice greatly accelerated apoptosis among pre-B and pre-T cells by 50% to 300% providing a mechanistic explanation for the lymphopenia and thymic atrophy long associated with this and other nutritional deficiencies. Since apoptosis has been shown to be altered by aging and nutritional status, it seemed important to determine how ZD affected these processes in the aged mouse. It was quickly discovered that the pre-B cells were reduced by 80% in the 28 month aged mouse making further studies problematic. In marked contrast to suboptimal zinc, caloric restriction (CR) which when initiated in younger mice delayed the onset of autoimmunity and immunosenescence. CR appeared to also slow the aging of mitochondria and, thereby, reduced the release of reactive oxygen species that damage cells. Thus, it is probable that CR also helped maintain the integrity of mitochondria and apoptotic processes as mice aged. Though CR is not a very practical nutritional model for humans, the outcome of these studies reinforce the potential value of anti-oxidants in our diets. In contrast to their normal nutritional role some nutrients especially small amounts of free metals can induce apoptosis. There is considerable zinc in neurons. As will be discussed, a number of investigators think that this zinc is released during Alzheimer's, Parkinsons's, or brain injury and accelerates apoptosis in surrounding tissues causing greater damage. Data are discussed that indicate nanomoles of free zinc is, indeed, a potent inducer of apoptosis in a variety of tissues. In sum, there is no doubt that nutritional status as well as individual nutrients can modulate apoptosis and that their impact on cell death may become greater in the aged.     

恶性肿瘤患者肌肉减少症的诊断与营养干预

肌肉减少症是恶性肿瘤患者常见的临床综合征之一，可视为发病、死亡等不良预后的一项独立危险因素。主要评估方法为CT、MRI、PET等成像技术。肌肉减少症的发生、发展与肿瘤恶病质关系密切，且与抗肿瘤治疗相互影响。近年来，不断涌现出采取营养支持、药物和运动等综合干预手段的临床研究，其中不少取得了效果。肌肉减少症在恶性肿瘤治疗中具有不可忽视的临床价值，其发病机制复杂，疗效和安全性尚需更多高级别循证依据支持。     

膳食蛋白质与老年肌肉衰减综合征

随着人类寿命的日趋延长,伴随增龄而发生的人体脏器功能衰退和多种增龄性疾病明显增多,骨质疏松、骨关节炎等骨骼疾病严重地影响着老年人的生活质量。虽然这些代谢性骨病已引起人们的广泛关注,但对骨骼肌在增龄过程中的变化的有关研究较少。     

Epidemiology and consequences of sarcopenia

Sarcopenia is an evolving concept and the current definition of sarcopenia includes both a loss of muscle strength and loss of muscle mass. However, despite the increasing knowledge and improved technology, a worldwide operational definition of sarcopenia applicable across racial/ethnic groups and populations lacks consensus. As a result the prevalence of sarcopenia (8 to 40% of older people over 60 years) varies depending on the study sample (namely the age of the sample), the definition, and the assessment tool used. DXA is the main assessment method used to evaluate muscle mass, which is further adjusted to height, weight fat mass, or BMI to obtain an index of sarcopenia. Cross-sectional analyses seemed to prove an association between low muscle mass and functional decline, but these results were not consistent when analysed longitudinally over time. This inconsistency could be due to methodological issues as the selected populations in the cohorts where autonomous, community-dwelling, older people. In this highly active population decreases in muscle mass might be not as important as decreases in strength to predict functional decline. The aim of the present paper was to perform a comprehensive review of the literature on the epidemiology of sarcopenia and its consequences to be presented on November 13th and 14th 2008, at the Carla Workshop.     

维持性血液透析患者肌少症患病率的meta分析

目的 系统评价维持性血液透析患者骨骼肌减少症（肌少症）的患病率情况。方法 全面检索中英文数据库:中国知网（CNKI）、中国生物医学文献数据库（CBM）、万方数据库（Wanfang Date）、维普数据库（VIP）,英文数据库Pubmed、Embase、web of science、EBSCO查找有关维持性血液透析患者肌少症患病情况的相关研究。对纳入的文献按照纳排标准进行筛选、提取所需数据并按照标准严格进行文献质量评价后,通过Stata 12.0软件进行meta分析。结果 本研究最终纳入了15篇文献,共计2 561例维持性血液透析患者,文献质量评价均为中高等质量文献。Meta分析结果显示,维持性血液透析患者肌少症总患病率为31.2%（95%CI:24.9%～37.6%）,亚洲患者患病率为31.8%（95%CI:24.0%～39.6%）。男性肌少症患病率较女性患者高（37.0% vs 28.0%）,使用AWGS诊断标准肌少症患病率高于EWGSOP诊断标准（36.8% vs 26.2%）,使用DEXA肌量评估方法肌少症患病率稍低于BIA肌量评估方法（29.2% vs 32.0%）。结论 维持性血液透析患者肌少症患病率较高,需开展干预研究。     

肿瘤相关性肌肉减少症的发病机制与干预措施

肿瘤患者肌肉减少症发病机制比较复杂,涉及肿瘤和机体新陈代谢的各个方面,主要与蛋白质分解加速及合成不足有关.肌肉减少症能预测肿瘤患者药物治疗剂量限制毒性反应、增加并发症、降低生存率.肿瘤患者肌肉减少症的治疗包括营养干预、运动干预、激素及其他治疗.单一的治疗方式,不能逆转患者的临床结局.目前各种干预措施仍处于探索阶段,有待更多的循证研究支持.     

Aged with sarcopenia: an approach of nursing care

In the grow old process organic and functional damages happening, wich rhythm and intensity change from person to person and that finish to reduce the ability from each person has to adapt the environment, making more visible and vulnerable to illness process, that are the perturbation produced in the body by the illness taking the person to a natural physical decline. Pain and disorders in the muscle skeletal system are the most frequent complain in the old age and the second cause of inability in this group. This fact is comprehensible now that many diseases of the muscle skeletal system have more incidence with the advance of age, beside others that are almost exclusive of these population and are chronic illness, not deadly with cumulative frequence ones predisposing the others. Is in this context that is situated the responsability of the attention and care of the older with sarcopenia, having to the nursing like member of a interdisciplinar group, make efforts to act in the prevention, guidance, supervision and management of the assistance.