Doehner Wolfram, Turhan Guelistan, Leyva Francisco, Rauchhaus Mathias, Sandek Anja, Jankowska Ewa A, von Haehling Stephan, Anker Stefan D
Center for Stroke Research Berlin (CSB), Charite - Universitätsmedizin Berlin, Berlin, Germany.
German Center for Cardiovascular Diseases (DZHK), Partner Site Berlin, Berlin, Germany.
ESC Heart Fail. 2015 Jun;2(2):85-89. doi: 10.1002/ehf2.12035. Epub 2015 Apr 30.
Chronic heart failure (CHF) is associated with insulin resistance, indicating impairment in the control of energy metabolism. Insulin resistance in CHF relates to symptomatic status and independently predicts poor prognosis. We sought to determine whether insulin sensitivity is related to skeletal muscle strength in patients with CHF, taking into account muscle size and perfusion.
Quadriceps muscle size (square centimetre cross-sectional area at mid-femur level, computed tomography), isometric quadriceps muscle strength [absolute (in N) and strength per unit muscle area (N/cm )], resting-leg blood flow (plethysmography) and maximal oxygen consumption (treadmill exercise test) were measured in 33 patients with CHF (left ventricular ejection fraction 28 ± 3.2%, mean ± Standard Error of the mean (SEM)) and 20 healthy controls. Insulin sensitivity was assessed by intravenous glucose tolerance tests and minimal modelling analysis.
Right quadriceps strength (-27.0%, P < 0.0001), strength per muscle area (-18.0%, P < 0.003) and insulin sensitivity (-64.2%, P < 0.001) were lower in patients with CHF. The correlation between insulin sensitivity and absolute muscle strength was significant in the CHF group (r = 0.54, P = 0.001) and borderline in controls (r = 0.47, P = 0.06). This association remained significant between insulin sensitivity and strength per muscle area (CHF: r = 0.52, P < 0.01; controls: r = 0.62, P < 0.05). In stepwise regression analyses in CHF, only insulin sensitivity emerged as a predictor of strength per unit area of muscle [standardized coefficient (SC) = 0.45, P = 0.006; diuretic dose, SC = -0.31, P = 0.051; R = 0.37, P = 0.001], while age, left ventricular ejection fraction, maximal oxygen consumption, fasting glucose and insulin and blood flow were excluded. In controls, only insulin sensitivity remained in the final regression model (SC = 0.62, P = 0.004; R = 0.39, P = 0.004).
The myofibril contractile function of the quadriceps, i.e. functional quality of skeletal muscle, is strongly related to insulin sensitivity in patients with CHF and in healthy controls, independently of muscle size. Therapies aimed at improving insulin sensitivity in patients with CHF may clarify whether this relationship is causal.
慢性心力衰竭（CHF）与胰岛素抵抗相关，提示能量代谢控制受损。CHF中的胰岛素抵抗与症状状态相关，并能独立预测不良预后。我们试图确定CHF患者的胰岛素敏感性是否与骨骼肌力量相关，同时考虑肌肉大小和灌注情况。
对33例CHF患者（左心室射血分数28±3.2%，均值±均值标准误）和20名健康对照者测量股四头肌大小（股骨中段水平的平方厘米横截面积，计算机断层扫描）、股四头肌等长肌力[绝对值（牛顿）和单位肌肉面积肌力（N/cm²）]、静息腿部血流（体积描记法）和最大耗氧量（跑步机运动试验）。通过静脉葡萄糖耐量试验和最小模型分析评估胰岛素敏感性。
CHF患者的右侧股四头肌力量（-27.0%，P<0.0001）、单位肌肉面积肌力（-18.0%，P<0.003）和胰岛素敏感性（-64.2%，P<0.001）较低。CHF组中胰岛素敏感性与绝对肌肉力量之间的相关性显著（r = 0.54，P = 0.001），对照组中接近显著（r = 0.47，P = 0.06）。胰岛素敏感性与单位肌肉面积肌力之间的这种关联在CHF组（r = 0.52，P<0.01；对照组：r = 0.62，P<0.05）中仍然显著。在CHF的逐步回归分析中，只有胰岛素敏感性成为单位肌肉面积肌力的预测因素[标准化系数（SC）= 0.45，P = 0.006；利尿剂剂量，SC = -0.31，P = 0.051；R² = 0.37，P = 0.001]，而年龄、左心室射血分数、最大耗氧量、空腹血糖、胰岛素和血流被排除。在对照组中，最终回归模型中仅保留胰岛素敏感性（SC = 0.62，P = 0.004；R² = 0.39，P = 0.004）。
股四头肌的肌原纤维收缩功能，即骨骼肌的功能质量，在CHF患者和健康对照者中与胰岛素敏感性密切相关，与肌肉大小无关。旨在改善CHF患者胰岛素敏感性的治疗可能会阐明这种关系是否为因果关系。
