MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK.
MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Metabolic and Molecular Physiology, University of Nottingham, Queen's Medical Centre, Nottingham, UK; School of Life Sciences, University of Nottingham, Queen's Medical Centre, Nottingham, UK; National Institute for Health Research (NIHR) Nottingham Biomedical Research Centre, Nottingham University Hospitals and University of Nottingham, Queen's Medical Centre, Nottingham, UK.
Clin Nutr. 2022 Mar;41(3):709-722. doi: 10.1016/j.clnu.2022.01.023. Epub 2022 Feb 1.
BACKGROUND & AIMS: Elective surgery induces skeletal muscle wasting driven by an imbalance between muscle protein synthesis and breakdown. From examination of diverse stable isotope tracer techniques, the dynamic processes driving this imbalance are unclear. This meta-analysis aimed to elucidate the mechanistic driver(s) of postoperative protein catabolism through stable isotope assessment of protein turnover before and after abdominal surgery.
Meta-analysis was performed of randomized controlled trials and cohort studies in patients undergoing elective abdominal surgery that contained measurements of whole-body or skeletal muscle protein turnover using stable isotope tracer methodologies pre- and postoperatively. Postoperative changes in protein synthesis and breakdown were assessed through subgroup analysis of tracer methodology and perioperative care.
Surgery elicited no overall change in protein synthesis [standardized mean difference (SMD) -0.47, 95% confidence interval (CI): -1.32, 0.39, p = 0.25]. However, subgroup analysis revealed significant suppressions via direct-incorporation methodology [SMD -1.53, 95%CI: -2.89, -0.17, p = 0.03] within skeletal muscle. Changes of this nature were not present among arterio-venous [SMD 0.61, 95%CI: -1.48, 2.70, p = 0.58] or end-product [SMD -0.09, 95%CI: -0.81, 0.64, p = 0.82] whole-body measures. Surgery resulted in no overall change in protein breakdown [SMD 0.63, 95%CI: -0.06, 1.32, p = 0.07]. Yet, separation by tracer methodology illustrated significant increases in urinary end-products (urea/ammonia) [SMD 0.70, 95%CI: 0.38, 1.02, p < 0.001] that were not present among arterio-venous measures [SMD 0.67, 95%CI: -1.05, 2.38, p = 0.45].
Elective abdominal surgery elicits suppressions in skeletal muscle protein synthesis that are not reflected on a whole-body level. Lack of uniform changes across whole-body tracer techniques are likely due to contribution from tissues other than skeletal muscle.
择期手术会引起骨骼肌消耗，这是由肌肉蛋白合成和分解之间的失衡驱动的。通过对多种稳定同位素示踪技术的检查，导致这种失衡的动态过程尚不清楚。本项荟萃分析旨在通过对腹部手术后使用稳定同位素示踪技术评估全身或骨骼肌蛋白质周转率来阐明术后蛋白质分解的机制驱动因素。
对接受择期腹部手术的患者进行随机对照试验和队列研究的荟萃分析，这些研究包含使用稳定同位素示踪方法术测量术前和术后的全身或骨骼肌蛋白质周转率。通过示踪方法和围手术期护理的亚组分析来评估术后蛋白质合成和分解的变化。
手术并未引起蛋白质合成的总体变化[标准化均数差（SMD）-0.47，95%置信区间（CI）：-1.32，0.39，p=0.25]。但是，亚组分析显示，直接掺入方法[SMD-1.53，95%CI：-2.89，-0.17，p=0.03]会显著抑制骨骼肌中的蛋白质合成。这种变化在动静脉[SMD 0.61，95%CI：-1.48，2.70，p=0.58]或终产物[SMD-0.09，95%CI：-0.81，0.64，p=0.82]的全身测量中不存在。手术也没有引起蛋白质分解的总体变化[SMD 0.63，95%CI：-0.06，1.32，p=0.07]。然而，示踪方法的分离表明，尿终产物（尿素/氨）显著增加[SMD 0.70，95%CI：0.38，1.02，p<0.001]，而动静脉测量中则没有这种情况[SMD 0.67，95%CI：-1.05，2.38，p=0.45]。
择期腹部手术会引起骨骼肌蛋白合成的抑制，而这种抑制在全身水平上并没有反映出来。全身示踪技术没有一致的变化，可能是由于除骨骼肌以外的组织的贡献。
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