Serum Metabolomic Response of Myasthenia Gravis Patients to Chronic Prednisone Treatment

Prednisone is often used for the treatment of autoimmune and inflammatory diseases but they suffer from variable therapeutic responses and significant adverse effects. Serum biological markers that are modulated by chronic corticosteroid use have not been identified. Myasthenia gravis is an autoimmune neuromuscular disorder caused by antibodies directed against proteins present at the post-synaptic surface of neuromuscular junction resulting in weakness. The patients with myasthenia gravis are primarily treated with prednisone. We analyzed the metabolomic profile of serum collected from patients prior to and after 12 weeks of prednisone treatment during a clinical trial. Our aim was to identify metabolites that may be treatment responsive and be evaluated in future studies as potential biomarkers of efficacy or adverse effects. Ultra-performance liquid chromatography coupled with electro-spray quadrupole time of flight mass spectrometry was used to obtain comparative metabolomic and lipidomic profile. Untargeted metabolic profiling of serum showed a clear distinction between pre- and post- treatment groups. Chronic prednisone treatment caused upregulation of membrane associated glycerophospholipids: phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, 1, 2-diacyl-sn glycerol 3 phosphate and 1-Acyl-sn-glycero-3-phosphocholine. Arachidonic acid (AA) and AA derived pro-inflammatory eicosanoids such as 18-carboxy dinor leukotriene B4 and 15 hydroxyeicosatetraenoic acids were reduced. Perturbations in amino acid, carbohydrate, vitamin and lipid metabolism were observed. Chronic prednisone treatment caused increase in membrane associated glycerophospholipids, which may be associated with certain adverse effects. Decrease of AA and AA derived pro-inflammatory eicosanoids demonstrate that immunosuppression by corticosteroid is via suppression of pro-inflammatory pathways. The study identified metabolomic fingerprints that can now be validated as prednisone responsive biomarkers for the improvement in diagnostic accuracy and prediction of therapeutic outcome.

泼尼松（Prednisone）常被用于治疗自身免疫性与炎症性疾病，但该药物存在治疗应答可变、不良反应显著的问题。目前尚未发现受长期糖皮质激素使用调控的血清生物标志物。重症肌无力（Myasthenia Gravis）是一种自身免疫性神经肌肉疾病，由针对神经肌肉接头突触后膜表面蛋白的抗体引发，进而导致肌无力。该疾病患者主要采用泼尼松治疗。本研究对一项临床试验中采集的患者接受泼尼松治疗前及治疗12周后的血清样本进行了代谢组学分析，旨在筛选可响应治疗的代谢物，以期在未来研究中作为疗效或不良反应的潜在生物标志物进行评估。本研究采用超高效液相色谱-电喷雾四极杆飞行时间质谱联用技术，获取了对比性的代谢组与脂质组谱图。血清非靶向代谢组分析结果显示，治疗前与治疗后组样本存在显著区分。长期泼尼松治疗可使膜相关甘油磷脂上调，包括磷脂酰胆碱、磷脂酰乙醇胺、磷脂酰丝氨酸、1,2-二酰基-sn-甘油-3-磷酸及1-酰基-sn-甘油-3-磷酸胆碱。花生四烯酸（AA）及其衍生的促炎性类二十烷酸（如18-羧基二去白三烯B4、15-羟基二十碳四烯酸）的水平则出现降低。研究还观察到氨基酸、碳水化合物、维生素及脂质代谢存在紊乱。长期泼尼松治疗引发的膜相关甘油磷脂上调，可能与部分不良反应相关。而花生四烯酸及其衍生促炎性类二十烷酸的水平降低，表明糖皮质激素的免疫抑制作用是通过抑制促炎通路实现的。本研究筛选得到的代谢组指纹图谱，未来可被验证为泼尼松响应性生物标志物，以提升诊断准确性并预测治疗结局。