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

吉兰-巴勒综合征（GBS）和慢性炎症性脱髓鞘性多根神经病变（CIDP）是免疫系统（人体对疾病和感染的自然防御）错误攻击神经的情况。这可能导致进行性瘫痪，在严重的情况下，人们可能失去行走、吞咽和呼吸的能力。大约每20名GBS患者中就有1人死亡，许多人留下了长期残疾。CIDP患者通常需要几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，帮助阻止有害抗体损害神经。血浆置换，也被称为血浆置换，有时被用来代替IVIG，它涉及到连接到一台机器上，从静脉中抽出血液，过滤掉有害抗体，然后将血液送回体内。对这些疾病的治疗只是部分有效。部分问题在于我们没有生物标记物（自然产生的分子）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，被称为“单分子分析仪”（SiMoA）的非常强大的机器使我们能够在比以前低100-2000倍的浓度下测量生物标志物（相当于能够检测一茶匙溶解在全尺寸奥林匹克游泳池中的糖）。在我的项目中，我将研究两种潜在的神经损伤的生物标志物，外周蛋白和周轴蛋白，并开发SiMoA检测方法来测量它们在血液中的含量。我将用干细胞在实验室的培养皿中培养人类周围神经细胞，干细胞有一种特殊的能力，可以变成不同的细胞类型，包括神经细胞。这些细胞来源于人体组织，可以在不需要使用动物的情况下大量生产用于多次实验。然后，我将人工破坏这些细胞，并测量损伤后释放的周周蛋白和外周蛋白的水平。最后，我将测量炎症性神经病变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）紊乱的水平进行比较，以确保外周蛋白和外周蛋白是外周神经特异性的。将我的研究成果从临床到临床的转化将会提高炎症性神经病变的临床和研究水平。在临床水平上，peripherin和periaxin将准确测量周围神经疾病，协助监测，识别复发和滴定治疗。至关重要的是，这将分别减少因过度治疗或治疗不足而产生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将有助于临床试验患者的选择，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.