Biochemistry and Biophysics of the Preocular Tear Film

描述（由申请人提供）：干眼症（DE）及其主要形式之一——慢性后睑炎（CPB）——是一种广泛存在的多因素疾病，通过损害视力降低数百万人的生活质量，尤其是老年人、妇女和生活在恶劣气候条件下的人。高达30%的普通人群受到DE的影响。目前，fda批准的唯一治疗DE和CPB的药物Restasis(R)对DE没有有效的治疗方法，对15%的患者有治疗效果，而安慰剂组只有5%。这种疾病与非常薄的富含脂质和蛋白质的眼表面结构——泪膜（TF）的变化有关。我们项目的长期目标是：1)重新定义TF的生化组成和三维结构，2)确定稳定或不稳定TF的主要生化和生物物理因素，从而确定那些对CPB和DE的发展至关重要的成分。我们的一般假设是：1)TF的脂质组成比以前认为的更复杂；2)由于非常特殊的脂质/脂质和脂质/蛋白质相互作用，TF结构稳定；3) TF不是完全液态的，而是具有类似液晶或凝胶的结构，由逐渐插入的层和带组成，这些层和带富含特定类型的分子和超分子复合物。该项目的目标如下。目的1。通过比较MGS和AT的脂质特征，确定TF的脂质成分及其可能来源，并识别和评估关键脂质成分在TF形成和维持中的作用，挑战目前关于人类TF主要由MGS形成的生化成分的观点。目标2。为了验证正常TF不是完全液态的假设，而是具有液晶状或凝胶状的动态纳米结构，由逐渐插入的层和区域组成，富含特定类型的分子和超分子复合物，通过脂质、蛋白质和其他分子之间的离子和亲疏水相互作用来稳定，其结构容易因脂质和蛋白质成分的改变而改变。泪液渗透压、眼温、混合、环境因素等。目标3。确定与正常受试者相比，CPB患者的DE症状和TF不稳定性的周期性增加是否与人AT脂质和MGS的周期性定性和定量变化有关。

DESCRIPTION (provided by applicant): Dry eye (DE), and one of its major forms - chronic posterior blepharitis (CPB) - is a widespread multifactorial disease that diminishes the quality of life of millions of people, especially elderly, women, and those who live in adverse climates, by impairing their vision. Up to 30% of the general population is affected by DE. No effective treatment for DE exists at present with the only FDA-approved drug for treating DE and CPB, Restasis(R), having a therapeutic effect in 15% of patients vs. 5% in the placebo group. The disease is linked to changes in the very thin lipid- and protein rich ocular surface structure called tear film (TF). The long-term goals of our project are: 1) to redefine the biochemical composition and 3-D structure of TF, and 2) to determine the major biochemical and biophysical factors that stabilize or destabilize TF and hence those components important for the development of CPB and DE in general. Our general hypotheses are that: 1) the lipid composition of TF is more elaborate than previously thought; 2) the TF structure is stabilized due to very specific lipid/lipid and lipid/protein interactions; and, 3) TF is not quite liquid but instead has either a liquid crystal-like, or a gel-like structure and is composed of gradually intercalating layers and zones enriched with particular types of molecules and supramolecular complexes. The aims of the project are as follows. Aim 1. To challenge the current views on the biochemical composition of human TF as formed primarily of MGS by comparatively characterizing the lipids of MGS and AT, determining the lipid components of TF and their likely sources, and identifying and evaluating the roles of the critical lipid components in the formation and maintaining of TF. Aim 2. To test the hypothesis that normal TF is not quite liquid but instead has an either liquid crystal-like or a gel- like dynamic nanostructure composed of gradually intercalating layers and zones enriched with particular types of molecules and supramolecular complexes which is stabilized by ionic and hydrophilic/hydrophobic interactions between lipids, proteins, and other molecules and whose structure is susceptible to changes due to alterations in its lipid and protein compositions, tear osmolality, ocular temperature, mixing, environmental factors, etc. Aim 3. To determine whether or not there are cyclic qualitative and quantitative changes in human AT lipids and MGS that could be associated with the cyclic increase of DE symptoms and TF instability in CPB patients compared with normal subjects. PUBLIC HEALTH RELEVANCE: Dry eye syndrome (DE) in general, and one of its major forms - chronic posterior blepharitis (CPB) - is a wide- spread condition that severely deteriorates the quality of life of millions of people by impairing their vision. No effective treatment for DE exists at present with the only FDA approved prescription drug for treating CPB, Restasis(R), having a therapeutic effect in 15% of patients vs. 5% in the placebo group. The disease is related to abnormal changes in lipids and proteins in the preocular tear film (TF). The goal of the project is to investigate the biochemical changes in lipid composition of human aqueous tears and meibomian gland secretions and the corresponding biophysical changes in TF that occur in CPB in order to uncover their mechanisms and develop more effective diagnostic tests and treatments of this condition.