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。     

Thigh muscle volume in relation to age, sex and femur volume

Secular changes and intra-individual differences in body shape and size can confound cross-sectional studies of muscle ageing. Normalising muscle mass to height squared is often suggested as a solution for this. We hypothesised that normalisation of muscle volume to femur volume may be a better way of determining the extent of muscle lost with ageing (sarcopenia). Thigh and femur muscle volumes were measured from serial magnetic resonance imaging sections in 20 recreationally active young men (mean age 22.4 years), 25 older men (72.3 years), 18 young women (22.1 years) and 28 older women (72.0 years). There were no age-related differences in femur volume. The relationship between thigh muscle volume and femur volume (R² = 0.76; exponent of 1.12; P < 0.01) was stronger than that with height (R² = 0.49; exponent of 3.86; P < 0.01) in young participants. For young subjects, the mean muscle/bone ratios were 16.0 and 14.6 for men and women, respectively. For older men and women, the mean ratios were 11.6 and 11.5, respectively. The Z score for the thigh muscle/bone volume ratio relative to young subjects was −2.2 ± 0.7 for older men and −1.4 ± 0.8 for older women. The extent of sarcopenia judged by the muscle/bone ratio was approximately twice that determined when normalising to height squared. These data suggest that the muscle/bone ratio captures the intra-individual loss of muscle mass during ageing, and that the age-related loss of muscle mass may be underestimated when normalised to height squared. The quadriceps seems relatively more affected by ageing than other thigh muscles.     

Age related differences in maximal and rapid torque characteristics of the leg extensors and flexors in young,middle-aged and old men

The decline in maximal and rapid isometric torque characteristics may compromise functional living abilities in aging adults while loco-motor muscle groups, such as the leg extensors and flexors, may exhibit different torque–time age related decreases. The purpose of the present study was to examine the age-related differences in maximal and rapid torque characteristics of the leg extensor and flexor muscle groups in young, middle-aged, and old men. Sixty-five healthy men were categorized by age as young (n = 25; mean ± SD age = 24.9 ± 3.0 years), middle-aged (n = 22; age = 50.6 ± 4.0 years), and old (n = 18; age = 66.8 ± 4.5 years). Participants performed maximal voluntary contractions (MVCs) of the leg extensors and flexors and an estimated thigh cross sectional area (eThighCSA) assessment. Peak torque (PT), peak rate of torque development (RTDpeak), absolute RTD and the contractile impulse (IMPULSE) were calculated at time intervals of 30, 50, 100 and 200 ms from the torque–time curve. Relative RTD was calculated at 10, 20, 30, 40 and 50% of MVC from the normalized torque–time curves. PT, RTDpeak and later rapid torque variables (RTD100, RTD200, and IMPULSE200) were greater (P ≤ 0.05) in the young and middle-aged when compared to the old men for both muscle groups. Early (RTD30,50; IMPULSE30,50) and late (IMPULSE100) rapid torque variables were greater (P ≤ 0.05) for the young and middle-aged than the old men for the leg extensors but not the leg flexors, except for RTD30, in which there was no difference between young and old. There were no differences for all relative RTD variables between age groups (P > 0.05). eThighCSA was lower in the old compared to the young (P = 0.001) and middle-aged (P = 0.016) men. Maximal and rapid torque characteristics were preserved in middle-aged men but greatly reduced in older men with differential effects at early and late portions of the torque–time curve between the leg extensors and flexors. Significant decreases in absolute maximal and rapid torque production with no change in relative RTD across age groups and lower eThighCSA in old men may suggest that the loss of rapid torque producing capacities observed in older men may be largely a function of mechanisms associated with loss of muscle strength and muscle mass.     

骨量-肌量减少性肥胖综合征与2型糖尿病关系的研究进展

随着人口老龄化进程加剧，增龄性疾病发病率增高，多病共存对老年人的健康造成极大危害，探讨骨量-肌量减少性肥胖综合征与2型糖尿病之间的关系可为治疗老年人多病共存提供理论依据。本文就骨量-肌量减少性肥胖综合征与2型糖尿病的关系予以综述，得出二者之间关系密切，相互影响，综合治疗可有效改善整体预后，提高生存质量。     

Skeletal muscle growth defect in human growth hormone transgenic rat is accompanied by phenotypic changes in progenitor cells

Growth hormone (GH) is known to have a pivotal role in the maintenance of skeletal muscle mass. Sarcopenia, the loss of skeletal muscle mass, is a common phenomenon in aging, and it is widely accepted that sarcopenia is largely attributed to age-related decline in GH secretion. In the present study, we tested if human growth hormone transgenic rats (GH-TG rats) whose plasma GH levels are maintained relatively low could be an appropriate model for sarcopenia. Analyses of GH-TG rats revealed that they exhibit skeletal muscle growth defect as well as atrophy of myofibers. The number of myofibers in tibialis anterior muscle was comparable to that of WT rats, while the proportion of type I slow myofibers in tibialis anterior muscle was increased in GH-TG rats after 5 months. Neither increased expression of ubiquitin ligases, MuRF1 and MAFbx, nor indication of apoptotic cell death was observed. Notably, myogenic differentiation potential of skeletal muscle progenitor cells in GH-TG rats was lower than WT rats, and this was accompanied by increased adipogenic potential. These results indicate that GH-TG rats could be a useful model to elucidate the mechanism of sarcopenia induced by reduced GH action and raised the possibility that decreased GH action may cause an alteration of differentiation potential of skeletal muscle progenitor cells.     

Relationship between Sarcopenic Obesity and Cardiovascular Disease Risk as Estimated by the Framingham Risk Score

This study was conducted to assess the association between sarcopenic obesity and cardiovascular disease (CVD) risk in Korean adults (n=3,320; ≥40 yr) who participated in the 5th Korean National Health and Nutrition Examination Survey in 2010. The appendicular skeletal muscle mass divided by body weight was calculated for each participant; participants with values <1 standard deviation below the mean reference value (i.e., aged 20-39 yr) were considered sarcopenic. Subjects were further classified into 4 groups according to their obesity (i.e., body mass index ≥25 kg/m²) and sarcopenic status. Individuals'' 10-yr CVD risk was determined using the Framingham risk model. The sarcopenic obese group had more participants (43.8% men, 14.6% women) with a high risk of CVD (≥20%). The sarcopenic obese group was associated with an increased 10-yr CVD risk than the non-sarcopenic, non-obese group (odds ratio [OR], 2.49; 95% confidence interval [CI], 1.53-4.06, P<0.001 in men; OR, 1.87; 95% CI, 1.02-3.41, P=0.041 in women). Sarcopenic non-obese and non-sarcopenic obese subjects were not associated with an increased 10-yr CVD risk. Sarcopenic obesity, but not non-sarcopenic obesity, was closely associated with an increased CVD risk in Korean adults.

Graphical Abstract

相似文献   

CT评价腹股沟疝患者肌肉质量方法的前瞻性研究

目的　应用CT技术评价老年腹股沟疝患者的肌肉质量。方法　拟接受腹股沟疝手术、年龄在70~90岁的男性住院患者30例为研究对象,40~50岁10名男性健康受试者为成人对照组,10名同年龄段接受健康查体老年人为老年对照组,记录一般资料,应用CT技术扫描腹部和大腿,通过专用软件计算相应肌肉面积。结果　研究组握力（36.44±14.15）kg明显少于成人对照组（77.30±22.69）kg （P=0.001）,研究组小腿围（25.18±2.31）cm 明显少于成人对照组（27.62±2.33）cm （P=0.006）。CT扫描显示研究组与成人对照组L3（第3腰椎）平面腹部面积、皮下脂肪面积、腹腔脂肪面积和竖脊肌总面积相近,研究组腹部肌肉面积（12 094.23±1 970.30）mm2和竖脊肌肌肉面积（1 642.60±266.90）mm2明显少于成人对照组的（17 462.00±1 600.58）mm2和（2 003.50±350.91）mm2（P=0.001, P=0.007）。L3骨骼肌指数为50.64±7.52,存在肌肉减少症（≤52.4）为66.7 %（20/30）。与同年龄正常查体老人腹部肌肉CT结果相似。研究组下肢骨骼肌面积明显少于成人对照组（P=0.001）,下肢脂肪和股骨面积两组比较差异无统计学意义（P＞0.05）。结论　老年腹股沟疝患者肌肉质量和力量明显低于成人对照组,CT技术可作为评价工具。