Krumpolec Patrik, Klepochová Radka, Just Ivica, Tušek Jelenc Marjeta, Frollo Ivan, Ukropec Jozef, Ukropcová Barbara, Trattnig Siegfried, Krššák Martin, Valkovič Ladislav
High Field MR Center, Department of Biomedical Imaging and Image-guided Therapy, Medical University of Vienna, Vienna, Austria.
Biomedical Research Center, Institute of Experimental Endocrinology, Slovak Academy of Sciences, Bratislava, Slovakia.
Front Physiol. 2020 Jun 29;11:644. doi: 10.3389/fphys.2020.00644. eCollection 2020.
Aging is associated with changes in muscle energy metabolism. Proton (H) and phosphorous (P) magnetic resonance spectroscopy (MRS) has been successfully applied for non-invasive investigation of skeletal muscle metabolism. The aim of this study was to detect differences in adenosine triphosphate (ATP) production in the aging muscle by P-MRS and to identify potential changes associated with buffer capacity of muscle carnosine by H-MRS. Fifteen young and nineteen elderly volunteers were examined. H and P-MRS spectra were acquired at high field (7T). The investigation included carnosine quantification using H-MRS and resting and dynamic P-MRS, both including saturation transfer measurements of phosphocreatine (PCr), and inorganic phosphate (Pi)-to-ATP metabolic fluxes. Elderly volunteers had higher time constant of PCr recovery (τ ) in comparison to the young volunteers. Exercise was connected with significant decrease in PCr-to-ATP flux in both groups. Moreover, PCr-to-ATP flux was significantly higher in young compared to elderly both at rest and during exercise. Similarly, an increment of Pi-to-ATP flux with exercise was found in both groups but the intergroup difference was only observed during exercise. Elderly had lower muscle carnosine concentration and lower postexercise pH. A strong increase in phosphomonoester (PME) concentration was observed with exercise in elderly, and a faster Pi:PCr kinetics was found in young volunteers compared to elderly during the recovery period. Observations of a massive increment of PME concentration together with high Pi-to-ATP flux during exercise in seniors refer to decreased ability of the muscle to meet the metabolic requirements of exercise and thus a limited ability of seniors to effectively support the exercise load.
衰老与肌肉能量代谢的变化有关。质子（H）和磷（P）磁共振波谱（MRS）已成功应用于骨骼肌代谢的无创研究。本研究的目的是通过P-MRS检测衰老肌肉中三磷酸腺苷（ATP）生成的差异，并通过H-MRS识别与肌肉肌肽缓冲能力相关的潜在变化。对15名年轻志愿者和19名老年志愿者进行了检查。在高场（7T）下采集H和P-MRS波谱。研究包括使用H-MRS进行肌肽定量以及静息和动态P-MRS，两者均包括磷酸肌酸（PCr）的饱和转移测量以及无机磷酸盐（Pi）与ATP的代谢通量。与年轻志愿者相比，老年志愿者的PCr恢复时间常数（τ）更高。两组运动后PCr与ATP的通量均显著下降。此外，无论在静息状态还是运动过程中，年轻组的PCr与ATP通量均显著高于老年组。同样，两组运动后Pi与ATP的通量均增加，但仅在运动过程中观察到组间差异。老年人的肌肉肌肽浓度较低，运动后pH值也较低。在老年人中，运动后磷酸单酯（PME）浓度大幅增加，并且在恢复期间，年轻志愿者的Pi:PCr动力学比老年人更快。老年人运动期间PME浓度大幅增加以及Pi与ATP通量较高，这表明肌肉满足运动代谢需求的能力下降，因此老年人有效承受运动负荷的能力有限。
