Lortie Jevin, Rush Benjamin, Osterbauer Katie, Colgan T J, Tamada Daiki, Garlapati Sujay, Campbell Toby C, Traynor Anne, Leal Ticiana, Patel Viharkumar, Helgager Jeffrey J, Lee Kenneth, Reeder Scott B, Kuchnia Adam J
Department of Nutritional Sciences, University of Wisconsin-Madison, Madison, WI, United States.
Department of Radiology, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, United States.
Front Rehabil Sci. 2022 May 30;3:896114. doi: 10.3389/fresc.2022.896114. eCollection 2022.
Establish bedside biomarkers of myosteatosis for sarcopenia and cachexia. We compared ultrasound biomarkers against MRI-based percent fat, histology, and CT-based muscle density among healthy adults and adults undergoing treatment for lung cancer.
We compared ultrasound and MRI myosteatosis measures among young healthy, older healthy, and older adults with non-small cell lung cancer undergoing systemic treatment, all without significant medical concerns, in a cross-sectional pilot study. We assessed each participant's rectus femoris ultrasound-based echo intensity (EI), shear wave elastography-based shear wave speed, and MRI-based proton density fat-fraction (PDFF). We also assessed BMI, rectus femoris thickness and cross-sectional area. Rectus femoris biopsies were taken for all older adults ( = 20) and we analyzed chest CT scans for older adults undergoing treatment ( = 10). We determined associations between muscle assessments and BMI, and compared these assessments between groups.
A total of 10 young healthy adults, 10 older healthy adults, and 10 older adults undergoing treatment were recruited. PDFF was lower in young adults than in older healthy adults and older adults undergoing treatment (0.3 vs. 2.8 vs. 2.9%, respectively, = 0.01). Young adults had significantly lower EI than older healthy adults, but not older adults undergoing treatment (48.6 vs. 81.8 vs. 75.4, = 0.02). When comparing associations between measures, PDFF was strongly associated with EI (ρ = 0.75, < 0.01) and moderately negatively associated with shear wave speed (ρ = -0.49, < 0.01) but not BMI, whole leg cross-sectional area, or rectus femoris cross-sectional area. Among participants with CT scans, paraspinal muscle density was significantly associated with PDFF (ρ = -0.70, = 0.023). Histological markers of inflammation or degradation did not differ between older adult groups.
PDFF was sensitive to myosteatosis between young adults and both older adult groups. EI was less sensitive to myosteatosis between groups, yet EI was strongly associated with PDFF unlike BMI, which is typically used in cachexia diagnosis. Our results suggest that ultrasound measures may serve to determine myosteatosis at the bedside and are more useful diagnostically than traditional weight assessments like BMI. These results show promise of using EI, shear wave speed, and PDFF proxies of myosteatosis as diagnostic and therapeutic biomarkers of sarcopenia and cachexia.
建立用于肌少症和恶病质的肌脂肪变性的床旁生物标志物。我们在健康成年人和接受肺癌治疗的成年人中，将超声生物标志物与基于磁共振成像（MRI）的脂肪百分比、组织学以及基于计算机断层扫描（CT）的肌肉密度进行了比较。
在一项横断面试点研究中，我们比较了年轻健康、老年健康以及正在接受全身治疗的非小细胞肺癌老年患者的超声和MRI肌脂肪变性测量值，所有参与者均无重大医疗问题。我们评估了每位参与者基于股直肌超声的回声强度（EI）、基于剪切波弹性成像的剪切波速度以及基于MRI的质子密度脂肪分数（PDFF）。我们还评估了体重指数（BMI）、股直肌厚度和横截面积。对所有老年成年人（n = 20）进行了股直肌活检，并对接受治疗的老年成年人（n = 10）的胸部CT扫描进行了分析。我们确定了肌肉评估与BMI之间的关联，并比较了各组之间的这些评估。
共招募了10名年轻健康成年人、10名老年健康成年人以及10名正在接受治疗的老年成年人。年轻成年人的PDFF低于老年健康成年人以及正在接受治疗的老年成年人（分别为0.3%、2.8%和2.9%，P = 0.01）。年轻成年人的EI显著低于老年健康成年人，但与正在接受治疗的老年成年人无差异（48.6、81.8和75.4，P = 0.02）。在比较测量值之间的关联时，PDFF与EI密切相关（ρ = √0.75，P < 0.01），与剪切波速度呈中度负相关（ρ = -0.49，P < 0.01），但与BMI、全腿横截面积或股直肌横截面积无关。在进行CT扫描的参与者中，椎旁肌密度与PDFF显著相关（ρ = -0.70，P = 0.023）。老年成年组之间炎症或降解的组织学标志物无差异。
PDFF对年轻成年人与两个老年成年组之间的肌脂肪变性敏感。EI对组间肌脂肪变性的敏感性较低，但与PDFF密切相关，这与通常用于恶病质诊断的BMI不同。我们的结果表明，超声测量可能有助于在床旁确定肌脂肪变性，并且在诊断上比BMI等传统体重评估更有用。这些结果显示了将EI、剪切波速度和PDFF作为肌少症和恶病质的诊断和治疗生物标志物的前景。
