摘要：上輪部角結膜炎(Superior Limbic Keratoconjunctivitis, SLK)是一個以上部球結膜鬆弛與相對瞼結膜發炎為表現的眼疾。此病症之致病機轉至今仍然未明。上輪部角結膜炎與結膜鬆弛症(Conjunctivochalasis)分別都有結膜鬆弛的特性，前者呈現上部結膜明顯的發炎反應，而後者則於下部結膜有近似於退化性的表現。在上輪部角結膜炎及結膜 鬆 弛 症 之 結 膜 纖 維 母 細 胞 中 都 可 以 看 到 基 質 金 屬 蛋 白 酵 素 (matrix metalloproteinase, MMP) 的過度表現，結膜鬆弛症的結膜纖維母細胞基質金屬蛋白酵素的表現會受到淚液中細胞因子(cytokine) (IL-1β and TNF-α)的調控；但是上輪部角結膜炎的基質金屬蛋白酵素過度表現的調控機轉及其淚液細胞因子的變化至今未明。此外，上輪部角結膜炎可見較多的肥胖細胞浸潤，而肥胖細胞所釋放的酵素與組織基質的破壞與基質金屬蛋白酵素的活化有關。結膜上皮角質化則為另一上輪部角結膜炎特有的病理變化，而細胞角質化與鈣離子所調節的細胞分化有關。眨眼導致上部結膜的反覆機械性磨損可造成氧化損傷(oxidative damage)，角質化的細胞更會惡化眨眼之機械性磨損。本研究團隊已收集 40 位上輪部角結膜炎病人及 20 位對照組病人結膜檢體，並培養8 個上輪部角結膜炎纖維母細胞株。本計畫將使用這些檢體並收集病人的淚液及以壓印細胞學採集結膜表皮細胞，分析上輪部角結膜炎病理組織中之肥胖細胞的來源及其活化狀況，及其與結膜鬆弛病人之淚液細胞因子，再合併上述淚液細胞因子與其所誘導之基質金屬蛋白酵素表現於結膜纖維母細胞和肥胖細胞合併培養的研究，另外也將透過對於結膜上皮細胞分析其活性含氧物種(reactive oxidative species)和鈣離子分布情形，以期進一步的了解上輪部角結膜炎的致病機轉。
Abstract: Superior limbic keratoconjunctivitis (SLK) is characterized by redundant superior bulbar conjunctiva and inflammation of superior bulbar and tarsal conjunctiva. Conjunctivochalasis is an aging process associated with redundant inferior bulbar conjunctiva. The etiologies of both SLK and conjunctivochalasis are still unknown. These two disease entities share the similarities in pathological change of conjunctiva with loosened subepithelial stroma and few inflammatory cells infiltration. Up-regulation of MMP-1 and MMP-3 of conjunctival fibroblast was found in SLK and conjunctivochalasis. Inflammatory cytokines, such as IL-1β and TNF-α derived from the ocular surface and tears, were found to be associated with increased expression of MMP-1 and MMP-3 in cultured fibroblasts of conjunctivochalasis. However, the profiles of tear cytokine have not yet been investigated in SLK. Mast cell infiltration is a unique pathological finding in SLK. The mediators of mast cell, chymase and tryptase, are shown with the abilities to degrade several different types of collagen and activate pro-matrix metalloproteinase (MMP)-1 and pro-MMP-3 which could lead to matrix degradation. Stimulating factors of mast cell, stem cell factor (SCF) and thymic stromal lymphopoeitin (TSLP), can be secreted by epithelial cell and fibroblast. However, the stimulus for the mast cell infiltration and the secretion of mast cell stimulating factors in SLK is still unknown Keratinized epithelium is another characteristic pathological finding of SLK comparing with conjunctivochalasis. Conjunctival epithelial cells share the same cytological change as keratinocytes to have keratinization as their terminal differentiation. Calcium is an important keratinization-associated factor to promote cell differentiation. Besides, mechanical trauma causing by upper eyelid blinking was proposed to be a possible etiology of SLK. Eyelid blinking over the keratinized conjunctival epithelium might aggravate the mechanical trauma and initiate a vicious cycle in SLK. Therefore, the oxidative damage from mechanical trauma might play some roles in the pathogenesis of SLK. We have collected 40 conjunctival paraffinized tissues from SLK patients and 20 control patients since 1997. There are also eight SLK surgical specimens and nine control ones collecting for primary conjunctival fibroblast culture since 2001. With this tissue bank, we have published two scientific articles related to SLK in 2008 and 2011 showing two major findings including: increased infiltration of mast cell in the subepithelial stroma of SLK conjunctival specimens and overexpression of MMP-1 and -3 in surgical specimens and cultured conjunctival fibroblasts from SLK patients, respectively. The goals in this project are to determine the role of mast cell in promoting subepithelial stroma loosening in SLK; to investigate the role of cytokine and the inter-relationship of mast cell and fibroblast in loosened supepithelial stroma; to characterize the involvement of oxidative damage, the profile of ROS, and keratinization-associated factor, calcium gradient, and calcium-sensing receptor in conjunctival epithelium of SLK and conjunctivochalsis. The experiments will be performed by in vitro cell culture, surgical samples from tissue bank, tear sample collection from patients and animal model. By breakdown analysis of the complex interaction of cytokine, mast cell, mechanical trauma and conjunctival cells, we hope to advance our understanding of the pathogenesis of SLK and conjuctivochalasis to provide pavestone for the treatment of these diseases.