Lack of adaptation to severe malnutrition in elderly patients

BACKGROUND & AIMS: Sarcopenia is a common feature in the healthy elderly. However, little is known on age-related modifications of body composition in malnourished patients. The aims of this cross-sectional study were to evaluate the effects of aging per se on body composition and resting energy expenditure (REE) in malnourished patients. METHODS: Ninety-seven non-stressed patients referred for chronic malnutrition (C-reactive protein <5 mg/l) were separated into two groups: middle-aged (26 female, 19 male, 48+/-15 yr), and elderly (26 female, 26 male, 79+/-6 yr). Body composition was assessed by bioelectrical impedance analysis and REE by indirect calorimetry. RESULTS: In middle-aged patients, body composition remained stable between moderate (body-mass index [BMI; in kg/m(2)] 16-18.5) and severe (BMI < 16) malnutrition, with similar values of fat-free mass (FFM), body cell mass (BCM) and fat mass (FM) as percentages of body weight, whereas in elderly patients malnutrition occurred at the expense of FFM and BCM, with unchanged FM absolute values. REE/FFM values remained stable in middle-aged patients at every stage of malnutrition, whereas they increased in elderly patients along with their degree of malnutrition. In multivariate analysis, both body composition and REE/FFM were influenced by sex, age, BMI and mid-arm circumference. CONCLUSION: Compared to younger patients, weight loss in the elderly leads to cachexia, with a preferential loss of FFM and BCM that may participate in the more severe outcomes observed in these patients. They also show elevated REE/FFM values that induce higher energy needs.     

Myotendinous alterations and effects of resistive loading in old age

The loss of muscle mass associated with ageing only partly explains the observed decline in muscle strength. This paper provides evidence of the contribution of muscular, tendinous and neural alterations to muscle weakness in old age and discusses the complex interplay between the changes of the contractile tissue with those of the tendinous tissue in relation to the mechanical behavior of the muscle as a whole. Despite the considerable structural and functional alterations, the elderly musculoskeletal system displays remarkable adaptability to training in old age and many of these adverse effects may be substantially mitigated, if not reversed, by resistive loading. The interplay between these muscular and tendinous adaptations has an impact both on the length-force and force-velocity relationships of the muscle and is likely to affect the range of motion, rate of force development, maximum force development and speed of movement of the older individual.     

Resistance training in the early postoperative phase reduces hospitalization and leads to muscle hypertrophy in elderly hip surgery patients--a controlled, randomized study

OBJECTIVES: To better understand how immobilization and surgery affect muscle size and function in the elderly and to identify effective training regimes. DESIGN: A prospective randomized, controlled study. SETTING: Bispebjerg University Hospital, Copenhagen, Denmark. PARTICIPANTS: Thirty-six patients (aged 60-86) scheduled for unilateral hip replacement due to primary hip osteoarthrosis. INTERVENTION: Patients were randomized to standard home-based rehabilitation (1 h/d x 12 weeks), unilateral neuromuscular electrical stimulation of the operated side (1 h/d x 12 weeks), or unilateral resistance training of the operated side (3/wk x 12 weeks). MEASUREMENTS: Hospital length of stay (LOS), quadriceps muscle cross-sectional area (CSA), isokinetic muscle strength, and functional performance. Patients were tested presurgery and 5 and 12 weeks postsurgery. RESULTS: Mean+/-standard error LOS was shorter for the resistance training group (10.0+/-2.4 days, P<.05) than for the standard rehabilitation group (16.0+/-7.2 days). Resistance training, but not electrical stimulation or standard rehabilitation, resulted in increased CSA (12%, P<.05) and muscle strength (22-28%, P<.05). Functional muscle performance increased after resistance training (30%, P<.001) and electrical stimulation (15%, P<.05) but not after standard rehabilitation. CONCLUSION: Postoperative resistance training effectively increased maximal muscle strength, muscle mass, and muscle function more than a standard rehabilitation regime. Furthermore, it markedly reduced LOS in elderly postoperative patients.     

慢性肾脏病伴肌少症患者骨密度改变的临床研究

目的探讨慢性肾脏病(chronic kidney disease,CKD)及伴肌少症患者的骨密度变化情况。方法健康对照组57例。CKD患者123例,男性61例,女性62例,平均年龄59. 8±12. 6岁。以核素肾动态显像获得的肾小球滤过率,将CKD组患者分为CKD1组(CKD1～2期)和CKD2组(CKD3～5期)。将研究对象分为肌少症组和非肌少症组,检测腰椎和髋关节骨密度及体质成份,评估肌肉质量、肌肉强度。结果①CKD2组患者腰椎、髋部和股骨颈骨密度T值均较对照组明显减低(P0. 05),差异有统计学意义;②CKD患者肌少症组腰椎、髋部和股骨颈骨密度均较非肌少症组骨密度T值显著减低(P0. 05),差异有统计学意义。肌少症组和非肌少症组骨质疏松发生率分别为41. 7%、20. 6%,差异有统计学意义(χ2=6. 367,P=0. 012)。结论骨密度随CKD病情进展而下降; CKD合并肌少症患者更易罹患骨质疏松。     

Role of L-arginine uptake mechanisms in renal blood flow responses to angiotensin II in rats

Aim: Reduced muscle force greater than expected from loss of muscle mass has been reported in ageing muscles. Impaired sarcoplasmic reticulum (SR) Ca²⁺ release has been implicated as a possible mechanism, and attributed to several factors, including loss of ryanodine receptor (RYR) expression and protein binding. The aim of this study was to evaluate muscle quality and SR Ca²⁺ release in ageing rats that were not so old that major atrophy had occurred. Methods: We collected in situ force data from the plantarflexor muscle group and muscle mass from the constituent muscles to determine muscle quality (force/mass) in adult (6–8 months) and ageing (24 months) rats (n = 8/group). We evaluated SR Ca²⁺ uptake and release, and determined expression of key proteins associated with Ca²⁺ release [RYR and FK506 binding protein (FKBP)] and uptake (SERCA, parvalbumin, calsequestrin). Results: Plantarflexor force and muscle quality were reduced with ageing (approx. 28 and 34%, respectively), but atrophy was limited, and significant only in the medial gastrocnemius (approx. 15%). The fast phase of SR Ca²⁺ release was reduced with ageing in both gastrocnemii, as was FKBP expression and FKBP–RYR binding, but RYR expression was not affected. Similar, but non‐significant changes were present in the plantaris, but the soleus muscle generally showed no ageing‐related changes. Conclusion: These data suggest a possible role for impaired SR Ca²⁺ release in ageing‐related loss of muscle quality, although not through loss of RYR expression.     

Dietary Pattern and Dietary Energy from Fat Associated with Sarcopenia in Community-Dwelling Older Chinese People: A Cross-Sectional Study in Three Regions of China

Associations between dietary patterns (DPs) and sarcopenia remain controversial, and fewer studies have mentioned the relationship between dietary energy composition and sarcopenia. The present cross-sectional study was conducted in three regions of China, to detect the associations between DPs and sarcopenia, and to identify the influencing nutrients. Exploratory factor analysis was conducted for DP identification. Logistic regressions were performed to explore the associations between DPs and sarcopenia. Dietary nutrients and dietary energy composition were calculated and compared among different DPs. Three DPs were identified from 861 community-dwelling older people. The “mushrooms–fruits–milk” pattern was negatively associated with sarcopenia (OR = 0.33, 95% CI = 0.14~0.77, p-trend = 0.009). Subjects in the highest quartile of the “mushrooms–fruits–milk” pattern showed more abundant intake (1.7 g/kg/d) of dietary protein, and lower percentage (31%) of energy from fat (PEF) than the other two DPs. Further analyses indicated that lower PEF (<30%) was negatively associated with sarcopenia. In conclusion, the “mushrooms–fruits–milk” pattern was negatively associated with sarcopenia in community-dwelling older Chinese people. This pattern showed abundant protein intake and low PEF, which may partially contribute to its protective effect on sarcopenia. Therefore, besides protein, dietary fat and PEF may also be considered in the prevention and management of sarcopenia.     

绝经后女性肌肉质量的影响因素研究

目的 探讨广州市绝经后女性肌肉质量的相关影响因素。方法 收集2019年6月至2020年12月广州市120名自愿参加本研究的绝经后女性的临床资料;其中符合纳入标准的有90例,年龄47～88岁,平均年龄(62.4±7.5)岁。所有受试者均记录其年龄、绝经年龄、绝经年限和身高、体重,计算BMI数值并进行骨密度测定、体成分分析检测肌肉质量。根据ASMI数值将受试者分为肌肉减少组及非肌肉减少组;分析两组年龄、绝经年龄、绝经年限和BMI数值、骨密度及肌肉质量的差异,比较两组患骨质疏松症的比率,利用Pearson相关性分析研究各因素与肌肉质量的相关程度,利用多元线性回归分析分析各指标与肌肉质量的相关性并得出回归方程。结果 肌肉减少组BMI和ASMI数值低于非肌肉减少组(P<0.05);肌肉减少组发生骨质疏松的比例大于非肌肉减少组(P>0.05); Pearson相关性分析提示绝经年龄(r=0.262,P=0.012)和BMI(r=0.771,P<0.001)与ASMI呈正相关;多元线性回归分析显示,影响绝经后女性ASMI值的因素主要有绝经年龄(P=0.037,B=0.034)和BM...     

“肌少-骨质疏松症”的研究现状与进展

人口的老龄化增加了许多老年慢性疾病的患病率,肌少症和骨质疏松症是与年龄相关的退行性疾病,具有相似的病理生理基础,包括遗传学、脂肪浸润、内分泌和机械因素等。"肌少-骨质疏松症"是一种新的老年综合征,在老年人群中广泛存在,并且可能带来严重的并发症,临床实践中应常规使用DXA、手握力、步行速度来评估老年人群的肌肉和骨骼情况,这对于有高危因素的老年患者可能会有帮助。针对"肌少-骨质疏松症"的研究可以更加全面的认识肌肉骨骼相关的退行性疾病,治疗上提示骨质疏松症和骨质疏松性骨折需要全面考虑肌肉和骨骼的情况并进行综合干预。尽管目前没有明确关于"肌少-骨质疏松症"的治疗药物,但有充分证据表明足够的蛋白质和钙摄入量,增加身体活动及维持维生素D的适当水平可以对骨骼和肌肉产生双重作用,这些都有助于改善身体的活动功能并减少老年人群跌倒和发生骨折的风险。笔者对"肌少-骨质疏松症"的流行病学、病理生理学、诊断、治疗和管理策略进行综述。