The Dubowitz Neuromuscular Centre, UCL Queen Square Institute of Neurology Division of Neuropathology & National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom; Department of Musculoskeletal Histopathology and the Wolfson Centre for Inherited Neuromuscular Diseases, RJAH Orthopaedic Hospital NHS Trust, Oswestry, SY10 7AG, United Kingdom; Department of Cellular Pathology, Salford Royal Hospital NHS Foundation Trust, Northern Care Alliance NHS Group, Stott Lane, Salford M6 8HD, United Kingdom; The Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, United Kingdom.
The Dubowitz Neuromuscular Centre, UCL Queen Square Institute of Neurology Division of Neuropathology & National Hospital for Neurology and Neurosurgery, London WC1N 3BG, United Kingdom; The Dubowitz Neuromuscular Centre, Great Ormond Street Hospital for Children NHS Foundation Trust, London WC1N 3JH, United Kingdom.
Neuromuscul Disord. 2021 May;31(5):371-384. doi: 10.1016/j.nmd.2021.02.007. Epub 2021 Feb 12.
Our retrospective immunohistochemical study of normal quadriceps muscle biopsies shows that embryonic myosin heavy chains are down-regulated by, or soon after, birth. Fetal myosin heavy chains are down-regulated by 4-6 months. Thus the presence of an appreciable number of fibres with embryonic myosin heavy chains at birth or of fetal myosin heavy chains after 6 months of age suggests a delay in maturation or an underlying abnormality. Regenerating fibres in dystrophic muscle often co-express both embryonic and fetal myosin heavy chains but more fibres with fetal than embryonic myosin heavy chains can occur. Embryonic myosin heavy chains are a useful marker of regeneration but effects of denervation, stress, disuse, and fibre maintenance also have to be taken into account. In neurogenic disorders fibres with embryonic myosin heavy chains are rare but fetal myosin heavy chain expression is common, particularly in 5q spinal muscle atrophy. Nuclear clumps in denervated muscle show fetal and sometimes embryonic myosin heavy chains. Developmentally regulated myosins are useful for highlighting the perifascicular atrophy in juvenile dermatomyositis. Our studies highlight the importance of baseline data for embryonic and fetal myosin heavy chains in human muscle biopsies and the importance of assessing them in a spectrum of neuromuscular disorders.
我们对正常股四头肌活检组织进行的回顾性免疫组织化学研究表明，胚胎肌球蛋白重链在出生时或出生后不久就会下调。胎儿肌球蛋白重链在 4-6 个月时下调。因此，在出生时存在大量具有胚胎肌球蛋白重链的纤维，或在 6 个月龄后存在胎儿肌球蛋白重链，提示成熟延迟或存在潜在异常。在营养不良性肌肉的再生纤维中，常常同时表达胚胎和胎儿肌球蛋白重链，但具有胎儿肌球蛋白重链的纤维比具有胚胎肌球蛋白重链的纤维更多。胚胎肌球蛋白重链是再生的有用标志物，但也要考虑到去神经、应激、废用和纤维维持的影响。在神经源性疾病中，具有胚胎肌球蛋白重链的纤维很少，但胎儿肌球蛋白重链的表达很常见，特别是在 5q 型脊髓性肌萎缩症中。去神经支配的肌肉中的核团显示出胎儿和有时是胚胎肌球蛋白重链。发育调节肌球蛋白可用于突出青少年皮肌炎中的筋膜旁萎缩。我们的研究强调了在人类肌肉活检中获得胚胎和胎儿肌球蛋白重链的基线数据的重要性，以及在一系列神经肌肉疾病中评估它们的重要性。
