碳水化合物的可用性影响运动期间的脂肪代谢;然而,完全肌糖原缺乏对最大脂肪氧化(MFO)率的影响仍然未知。我们的目的是检查McArdle病患者的MFO率,包括由肌肉糖原代谢完全阻断引起的遗传性疾病,与健康对照相比。9名患者(3名妇女,年龄36±12岁)和12名健康对照(4名女性,年龄40±13岁)进行了研究。还在McArdle(Pygmp50R*/p.50R*)和野生型雄性小鼠的骨骼肌(腓肠肌)和白色脂肪组织中确定了脂质转运/代谢的几种分子标记。峰值摄氧量(V♪O2峰值${\\dotV_{{{\\rm{O}}_{\\rm{2}}}{\\rm{峰值}}}$),MFO速率,运动强度引发MFO率(FATmax)和与MFO率相关的工作量在增量循环测力计测试期间通过间接量热法测定.尽管有低得多的V♪O2峰值${\\dotV_{{{\\rm{O}}_{\\rm{2}}}{\\rm{峰值}}}}$(24.7±4与42.5±11.4mLkg-1min-1,分别为;P<0.0001),患者的MFO率显示出较高的值(0.53±0.12vs.0.33±0.10gmin-1,P=0.001),和FATmax(94.4±7.2vs.41.3±9.1%的V♪O2峰值${\\dotV_{{{\\rm{O}}_{\\rm{2}}}{\\rm{峰值}}}}$,P<0.0001)和MFO率相关工作负载(1.33±0.35vs.0.81±0.54Wkg-1,P=0.020)比对照组。在小鼠脂质转运/代谢的分子标志物中没有发现总体的组间差异。总之,McArdle病患者表现出异常高的MFO率,他们在接近最大的运动能力下达到了这一点。在更多机械解释之前,这些发现支持糖原利用率对MFO率的影响,并表明这些患者具有独特的脂肪氧化能力,可能作为一种适应来补偿糖原代谢中的遗传阻滞,并指出MFO率是该疾病运动耐量的潜在限制因素。关键点:身体活跃的McArdle患者表现出异常的脂肪氧化能力。这些患者的最大脂肪氧化率接近最大运动能力。McArdle患者的运动耐量可能取决于最大的脂肪氧化率能力。呼吸过度可能会使某些患者的底物氧化测量模糊。动物模型显示总体上没有较高的脂质运输/代谢分子标记。
Carbohydrate availability affects fat metabolism during exercise; however, the effects of complete muscle glycogen unavailability on maximal fat oxidation (MFO) rate remain unknown. Our purpose was to examine the MFO rate in patients with McArdle disease, comprising an inherited condition caused by complete blockade of muscle glycogen metabolism, compared to healthy controls. Nine patients (three women, aged 36 ± 12 years) and 12 healthy controls (four women, aged 40 ± 13 years) were studied. Several molecular markers of lipid transport/metabolism were also determined in skeletal muscle (gastrocnemius) and white adipose tissue of McArdle (Pygm p.50R*/p.50R*) and wild-type male mice. Peak oxygen uptake ( V ̇ O 2 peak ${\\dot V_{{{\\rm{O}}_{\\rm{2}}}{\\rm{peak}}}}$ ), MFO rate, the exercise intensity eliciting MFO rate (FATmax) and the MFO rate-associated workload were determined by indirect calorimetry during an incremental cycle-ergometer test. Despite having a much lower V ̇ O 2 peak ${\\dot V_{{{\\rm{O}}_{\\rm{2}}}{\\rm{peak}}}}$ (24.7 ± 4 vs. 42.5 ± 11.4 mL kg-1 min-1 , respectively; P < 0.0001), patients showed considerably higher values for the MFO rate (0.53 ± 0.12 vs. 0.33 ± 0.10 g min-1 , P = 0.001), and for the FATmax (94.4 ± 7.2 vs. 41.3 ± 9.1 % of V ̇ O 2 peak ${\\dot V_{{{\\rm{O}}_{\\rm{2}}}{\\rm{peak}}}}$ , P < 0.0001) and MFO rate-associated workload (1.33 ± 0.35 vs. 0.81 ± 0.54 W kg-1 , P = 0.020) than controls. No between-group differences were found overall in molecular markers of lipid transport/metabolism in mice. In summary, patients with McArdle disease show an exceptionally high MFO rate, which they attained at near-maximal exercise capacity. Pending more mechanistic explanations, these findings support the influence of glycogen availability on MFO rate and suggest that these patients develop a unique fat oxidation capacity, possibly as an adaptation to compensate for the inherited blockade in glycogen metabolism, and point to MFO rate as a potential limiting factor of exercise tolerance in this disease. KEY POINTS: Physically active McArdle patients show an exceptional fat oxidation capacity. Maximal fat oxidation rate occurs near-maximal exercise capacity in these patients. McArdle patients\' exercise tolerance might rely on maximal fat oxidation rate capacity. Hyperpnoea might cloud substrate oxidation measurements in some patients. An animal model revealed overall no higher molecular markers of lipid transport/metabolism.