Marron Megan M, Allison Matthew, Kanaya Alka M, Larsen Britta, Wood Alexis C, Herrington David, Greenland Philip, Miljkovic Iva
Department of Epidemiology, Graduate School of Public Health, University of Pittsburgh, Pittsburgh, PA, United States.
Department of Family Medicine and Public Health, School of Medicine, University of California, San Diego, San Diego, CA, United States.
Front Physiol. 2021 Sep 27;12:713048. doi: 10.3389/fphys.2021.713048. eCollection 2021.
Skeletal muscle quantity and quality decrease with older age, which is partly attributed to ectopic fat infiltration and has negative metabolic consequences. To inform efforts to preserve skeletal muscle with aging, a better understanding of biologic correlates of quantity and quality of muscle and intermuscular adipose tissue (IMAT) is needed. We used targeted lipidomics of lipoprotein subfractions among 947 Multi-Ethnic Study of Atherosclerosis participants to provide a detailed metabolic characterization of area and density of abdominal muscle and IMAT. Serum lipoprotein subfractions were measured at the first visit using 1H-Nuclear Magnetic Resonance spectroscopy. Muscle and IMAT area (cm) and density (Hounsfield units) were estimated at visit 2 or 3 using computed tomography of the total abdominal, locomotion (psoas), and stabilization (paraspinal, oblique, rectus abdominis) muscles. We identified lipoprotein subfractions associated with body composition using linear regression adjusting for demographics, lifestyle, and multiple comparisons. Among 105 lipoprotein subfractions, 24 were associated with total muscle area (absolute standardized regression coefficient range: 0.07-0.10, -values ≤ 0.002), whereas none were associated with total muscle density. When examining muscle subgroups, 25 lipoprotein subfractions were associated with stabilization muscle area, with associations strongest among the obliques. For total IMAT area, there were 27 significant associations with lipoprotein subfractions (absolute standardized regression coefficient range: 0.09-0.13, -values ≤ 0.002). Specifically, 27 lipoprotein subfractions were associated with stabilization IMAT area, with associations strongest among the oblique and rectus abdominis muscles. For total IMAT density, there were 39 significant associations with lipoprotein subfractions (absolute standardized regression coefficient range: 0.10-0.19, -values ≤ 0.003). Specifically, 28 and 33 lipoprotein subfractions were associated with IMAT density of locomotion and stabilization (statistically driven by obliques) muscles, respectively. Higher VLDL (cholesterol, unesterified cholesterol, phospholipids, triglycerides, and apolipoprotein B) and lower HDL (cholesterol and unesterified cholesterol) were associated with higher muscle area, higher IMAT area, and lower IMAT density. Several associations between lipoprotein subfractions and abdominal muscle area and IMAT area and density were strongest among the stabilization muscles, particularly the obliques, illustrating the importance of examining muscle groups separately. Future work is needed to determine whether the observed associations indicate a lipoprotein profile contributing to worse skeletal muscle with fat infiltration.
骨骼肌的数量和质量会随着年龄的增长而下降,这部分归因于异位脂肪浸润,并会产生负面的代谢后果。为了指导在衰老过程中保护骨骼肌的工作,需要更好地了解肌肉以及肌间脂肪组织(IMAT)数量和质量的生物学关联因素。我们对动脉粥样硬化多族裔研究中的947名参与者的脂蛋白亚组分进行了靶向脂质组学分析,以详细描述腹部肌肉和IMAT的面积和密度的代谢特征。在首次就诊时使用1H核磁共振波谱法测量血清脂蛋白亚组分。在第2次或第3次就诊时,使用全腹部、运动(腰大肌)和稳定(椎旁肌、腹外斜肌、腹直肌)肌肉的计算机断层扫描来估计肌肉和IMAT的面积(平方厘米)和密度(亨氏单位)。我们使用线性回归并对人口统计学、生活方式和多重比较进行调整,确定了与身体成分相关的脂蛋白亚组分。在105种脂蛋白亚组分中,有24种与总肌肉面积相关(绝对标准化回归系数范围:0.07 - 0.10,P值≤0.002),而没有一种与总肌肉密度相关。在检查肌肉亚组时,有25种脂蛋白亚组分与稳定肌面积相关,其中与腹外斜肌的关联最强。对于总IMAT面积,有27种与脂蛋白亚组分的显著关联(绝对标准化回归系数范围:0.09 - 0.13,P值≤0.002)。具体而言,有27种脂蛋白亚组分与稳定IMAT面积相关,其中与腹外斜肌和腹直肌的关联最强。对于总IMAT密度,有39种与脂蛋白亚组分的显著关联(绝对标准化回归系数范围:0.10 - 0.19,P值≤0.003)。具体而言,分别有28种和33种脂蛋白亚组分与运动肌和稳定肌(由腹外斜肌驱动)的IMAT密度相关。较高的极低密度脂蛋白(胆固醇、游离胆固醇、磷脂、甘油三酯和载脂蛋白B)和较低的高密度脂蛋白(胆固醇和游离胆固醇)与较高的肌肉面积、较高的IMAT面积和较低的IMAT密度相关。脂蛋白亚组分与腹部肌肉面积以及IMAT面积和密度之间的几种关联在稳定肌中最为显著,尤其是腹外斜肌,这说明了分别检查肌肉群的重要性。未来需要开展工作来确定所观察到的关联是否表明脂蛋白谱会导致骨骼肌因脂肪浸润而变差。