Development of peripheral nerve specific biomarker assays: from in vitro neuropathy models to clinical validation

格林-巴利综合征（GBS）和慢性炎性脱髓鞘性多发性神经根神经病（CIDP）是免疫系统（身体对疾病和感染的天然防御）错误地攻击神经的情况。这可能会导致进行性瘫痪，在严重的情况下，人们可能会失去行走，吞咽和呼吸的能力。大约每20名GBS患者中就有1人死亡，许多人留下长期残疾。CIDP患者通常需要数年的免疫抑制药物治疗，以“抑制”免疫系统并减少炎症。或者，他们定期接受静脉注射免疫球蛋白（IVIG），这是一种昂贵且难以获得的治疗方法，由捐献的血液制成，用于帮助阻止有害的抗体损害神经。血浆置换，也称为血浆置换术，有时被用来代替IVIG，并涉及连接到一个机器，从静脉中取出血液，过滤掉有害的抗体，并返回血液到身体。这些疾病的治疗只有部分有效。部分问题在于，我们没有生物标志物（天然存在的分子）来诊断和评估对治疗的反应，因为受损神经释放的量很小，极难测量。最近，非常强大的机器称为“单分子分析仪”（SiMoA），使我们能够测量生物标志物的浓度比以前低100-2000倍（相当于能够检测一茶匙糖溶解在一个全尺寸的奥运会游泳池）。在我的项目中，我将研究两个潜在的神经损伤的生物标志物，peripherin和periaxin，并开发SiMoA测定来测量它们在血液中的浓度。我将使用干细胞在实验室的培养皿中培养人类外周神经细胞，干细胞具有转化为不同细胞类型的特殊能力，包括神经细胞。这些细胞来源于人体组织，可以大量生产用于多个实验，而不需要使用动物。然后，我将人工破坏这些细胞，并测量受损后释放的周蛋白和外周蛋白的水平。最后，我将测量炎症性神经病患者血液中的生物标志物，并将其与中枢神经系统（脑和脊髓）疾病的水平进行比较，以确保外周蛋白和周蛋白特异于外周神经。我的研究结果的临床到床边翻译将改善炎症性神经病的临床和研究方面。在临床水平上，外周蛋白和周蛋白将准确地测量周围神经疾病，协助监测，复发和治疗滴定的识别。至关重要的是，这将减少分别由于过度或不充分治疗而引起的副作用和长期残疾。神经特异性生物标志物也将使周围神经疾病的诊断更加准确，并有助于预测恢复的程度和速度。在研究层面上，periaxin和peripherin将有助于选择临床试验的患者，最大限度地提高周围神经研究的效率，并最终改善患者护理。

Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) are conditions where the immune system, the body's natural defence against illness and infections, mistakenly attacks the nerves. This can cause progressive paralysis and, in severe cases, people can lose their ability to walk, swallow and breathe. About 1 in 20 people with GBS die, and many are left with long-term disability. CIDP patients often require several years of treatment with immunosuppressant medicines to 'damp down' the immune system and reduce inflammation. Alternatively, they receive regular infusions of intravenous immunoglobulin (IVIG), a costly and scarcely available treatment made from donated blood, given to help stop the harmful antibodies damaging the nerves. A plasma exchange, also called plasmapheresis, is sometimes used instead of IVIG and involves being attached to a machine that removes blood from a vein, filters out the harmful antibodies, and returns the blood to the body.Treatments for these diseases are only partially effective. Part of the problem is that we do not have biomarkers (naturally occurring molecules) to diagnose and assess response to therapies, as the amounts released by the damaged nerves are tiny and extremely difficult to measure. Recently, very powerful machines called "single molecule analysers" (SiMoA) have enabled us to measure biomarkers at 100-2000 times lower concentrations than before (equivalent to being able to detect a teaspoon of sugar dissolved in a full-sized Olympic swimming pool).In my project, I will study two potential biomarkers of nerve damage, peripherin and periaxin, and develop SiMoA assays to measure them in the blood. I will grow human peripheral nerve cells in a dish in the laboratory using stem cells, which have a special ability to turn into different cell types, including those of the nerves. These cells are derived from human tissue and can be produced in large numbers for multiple experiments without the need to use animals. I will then artificially damage these cells and measure levels of periaxin and peripherin released after damage. Finally, I will measure the biomarkers in the blood of people with inflammatory neuropathies and compare levels with disorders of the central nervous system (brain and spinal cord) to ensure that peripherin and periaxin are specific to the peripheral nerve.Bench-to-bedside translation of my research findings will improve clinical and research aspects of the inflammatory neuropathies. On a clinical level, peripherin and periaxin will accurately measure peripheral nerve disease, assist with monitoring, identification of relapse and titration of treatment. Crucially, this will reduce side effects and long-term disability due to excessive or insufficient treatment respectively. Nerve-specific biomarkers will also make diagnosis of peripheral nerve disease more accurate, and will help predict degree and speed of recovery. On a research level, periaxin and peripherin will aid selection of patients for clinical trials, maximising efficiency of peripheral nerve research, and ultimately improving patient care.