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

格林-巴利综合征(GBS)和慢性炎症性脱髓鞘多神经根神经病(CIDP)是免疫系统错误攻击神经的情况，免疫系统是人体对疾病和感染的天然防御。这会导致进行性瘫痪，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，其中许多人长期残疾。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，减少炎症。或者，他们会定期接受静脉注射免疫球蛋白(IVIG)，这是一种由捐献的血液制成的昂贵且几乎无法获得的治疗方法，用于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，需要连接到一台机器上，从静脉中取出血液，过滤掉有害的抗体，并将血液返回体内。这些疾病的治疗只有部分有效。部分问题是，我们没有生物标记物(自然产生的分子)来诊断和评估治疗反应，因为受损神经释放的量很小，而且极其难以测量。最近，一台功能非常强大的被称为“单分子分析仪”(SiMoA)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(相当于能够检测到一茶匙的糖溶解在一个全尺寸的奥运会游泳池中)。在我的项目中，我将研究两种潜在的神经损伤生物标志物--外周蛋白和外周轴蛋白，并开发SiMoA分析方法来测量血液中的它们。我将在实验室的培养皿中使用干细胞培养人类周围神经细胞，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。这些细胞来自人类组织，可以大量生产，用于多次实验，而不需要使用动物。然后，我会人为地损伤这些细胞，并测量损伤后释放的周轴素和外周蛋白的水平。最后，我将测量炎症性神经病患者血液中的生物标记物，并将其与中枢神经系统(大脑和脊髓)的紊乱程度进行比较，以确保外周蛋白和外周轴蛋白是外周神经特有的。我的研究成果在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，外周蛋白和外周轴蛋白将准确测量周围神经疾病，帮助监测、识别复发和滴定治疗。至关重要的是，这将分别减少副作用和因治疗过多或治疗不足而导致的长期残疾。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，并有助于预测康复的程度和速度。在研究层面上，外周轴蛋白和外周蛋白将帮助选择进行临床试验的患者，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.