Preclinical evaluation of a new chemical cross-linker for the treatment of keratoconus

该提案的目的是确定一种新技术的安全性和有效性，以更安全、更有效地治疗威胁视力的圆锥角膜疾病。角膜是眼睛前部的透明窗口，允许光线进入，并提供80%的屈光力，将光线聚焦到眼睛后部的视网膜上。角膜的透明度受胶原纤维排列的影响，其形状与光线的折射有很大关系。圆锥角膜是一种进行性疾病，影响年轻人和工作年龄的人，在这种情况下，角膜变得畸形，严重干扰光线进入眼睛的折射。这是一种终生疾病，对工作年龄的成年人来说是一个巨大的健康和经济负担；它是英国角膜移植的主要原因。圆锥角膜的主要特征之一是角膜变薄，胶原纤维排列紊乱，导致机械稳定性丧失，与正常角膜相比，角膜的硬度降低了40%。通过在纤维之间形成交联来增加胶原结构的硬度的潜力已经导致了角膜交联术的发展。增加角膜的硬度可以通过保持角膜的完整性来减少疾病的进展，这是因为胶原结构中形成了强大的键。在过去的十年里，使用紫外线A(UVA)辐射和光敏剂核黄素联合使用的胶原交联剂已经在临床上使用，但它有一些局限性。特别是，暴露在UVA辐射下有可能对整个角膜的细胞产生毒性。这包括胶原蛋白结构中的角质形成细胞，这可能会导致长期的疤痕和雾霾。更重要的是，它会损害角膜内表面的单层细胞--角膜内皮。如果受损，这些细胞不会恢复，这可能会导致严重的视力丧失。此外，为了有效的硬化，有必要去除角膜上皮，即角膜外表面的保护性细胞层，以允许光敏剂穿透。这对患者来说是痛苦的，并增加了感染的风险。我们已经开发了一种化学交联液，并证明了它在体外猪组织中使角膜硬化的程度与现有治疗方法相似。此外，我们已经证明，它可以穿透角膜而不需要去除角膜上皮。此外，与UVA治疗相比，我们已经证明对角膜细胞没有毒性。这是一种简单的化学溶液，可以作为眼药水传递给患者，我们相信这种滴眼液可以在初级保健中完成，而不是在医院诊所。这项研究旨在沿着翻译途径开发我们的新型专利技术。我们将在活体大鼠模型中证明其生物安全性。我们将确定在兔模型中产生的硬化量和在4个月期间的稳定性，并利用这一点来优化临床程序。我们将与我们的临床合作伙伴密切合作，确保技术向临床发展。我们的目标是与一家公司建立合作伙伴关系，以确保商业翻译。在这个项目结束时，我们的目标是让技术准备好进行第一个人的安全研究。

The aim of the proposal is to determine the safety and efficacy of a novel technology for the safer and more effective treatment of the sight threatening disease keratoconus. The cornea is the clear window at the front of the eye that allows light to enter and provides 80% of the refractive power to focus the light onto the retina at the back of the eye. The transparency of the cornea is influenced by the alignment of collagen fibres and its shape has a major involvement in refraction of the light. Keratoconus is a progressive condition, affecting young and working age people, in which the cornea becomes misshapen significantly disrupting the refraction of light into the eye. It is a lifelong condition and a significant health and economic burden in work-age adults; and is a leading cause of corneal transplantation in the UK. One of the key features of keratoconus is the thinning of the cornea and disruption of the alignment of the collagen fibres leading to a loss of mechanical stability, with the stiffness of the cornea reducing by up to 40 % compared to a normal cornea. The potential to increase the stiffness of the collagen structure by forming cross-links between the fibres has led to the development of corneal cross-linking procedures. Increasing the stiffness of the cornea can reduce the progression of the disease by preserving corneal integrity due to strong bonds formed within the collagen structure. Over the past decade, collagen cross-linking using ultraviolet A (UVA) radiation combined with the photosensitiser riboflavin has been used clinically but it has several limitations. In particular, the exposure to UVA radiation risks toxicity to cells throughout the cornea. This includes the keratocytes within the collagen structure which can result in scarring and haze over the long term. More importantly, it can damage the corneal endothelium which is a monolayer of cells on the inner surface of the cornea. If damaged these cells do not recover and this can lead to severe loss of vision. Also for effective stiffening it is necessary to remove the corneal epithelium, the layer of protective cells on the outer corneal surface, to allow penetration of the photosensitiser. This is painful for the patient and increases the risk of infection. We have developed a chemical cross-linking solution and demonstrated that it stiffens the cornea in ex vivo pig tissue to a similar extent to the existing treatment. Also we have shown that it penetrates into the cornea without needing to remove the epithelium. Furthermore, in contrast to the UVA treatment, we have demonstrated no toxicity to the cells in the cornea. It is a simple chemical solution that can be delivered to the patient as an eye drop which we believe could be done in primary care rather than in a hospital clinic. This study is designed to develop our novel patented technology along the translational pathway. We will demonstrate its biological safety in an in vivo rat model. We will determine the amount of stiffening produced in a rabbit model and the stability of the stiffening over a 4 month period and use this to optimise the clinical procedure. We will work closely with our clinical partners to ensure the technology progresses towards the clinic. We aim to build a partnership with a company to ensure commercial translation. At the end of this project we aim to have the technology ready to proceed to a first-in-man safety study.