再生医学，或者说利用专门培养的组织和细胞来治疗损伤和疾病，在治疗包括心脏、胰腺和软骨在内的多种器官疾病方面取得成功。然而，利用再生技术来治疗角膜内皮(corneal endothelium)---角膜内表面的单细胞层---疾病的疗效性并不是太好。如今，一个研究团队开发出一种方法来加强移植的角膜内皮细胞(corneal endothelial cells， CECs)的附着，从而成功地开展角膜移植来修复病理性的角膜功能障碍。相关研究结果于2012年6月13日在线发表在American Journal of Pathology期刊上。
论文通讯作者、日本同志社大学生命与医学科学学院生物医学工程部门研究员Noriko Koizumi博士解释道，“角膜内皮功能障碍是严重性视力受损的主要原因，这是因为角膜内皮细胞起着维持角膜透明的作用。当将体外培养的CECs注入到角膜组织后，注入的CECs因房水流动(aqueous humor flow)而被冲洗走，导致它们的附着性较差。以前的研究证实Rho相关激酶(Rho-associated kinase， ROCK)信号干扰这种附着。我们发现将体外培养的CECs与抑制ROCK的低分子量化合物(ROCK抑制物Y-27632)一起进行移植，能够成功地让角膜恢复透明。”
研究人员以兔细胞作为研究对象，在实验室培养兔角膜内皮细胞(CECs)，并将它们注射到角膜内皮受损的兔眼的前房(anterior chamber)。基于角膜内皮功能的恢复情况，他们发现当把体外培养的兔CECs与Y-27632一起进行注射时，兔角膜在注射后48小时再次获得完全的透明度。相比之下，如果只注射兔CECs而不注射Y-27632，则导致角膜模糊不清和严重性肿胀。研究人员没有观察到与细胞注射疗法相关的并发症。当CECs与Y-27632一起注射而重建的角膜内皮表现出正常的六边形细胞形状。
鉴于兔CECs在体内高度增殖，研究人员利用猴角膜内皮细胞(CECs)开展另一轮实验，而且猴CECs更加类似于人CECs。在这些灵长类动物中进行CECs移植也能够成功地让角膜长期保持透明，同时产生单层六边形细胞，这就提示着利用ROCK抑制剂改变细胞附着性能可能是一种有效地治疗人角膜内皮疾病的方法。
尽管人们已经开发出外科技术来替换受损的角膜内皮，但是这些操作程序在技术上比较困难，而且因捐献的角膜比较短缺而面临挑战。Koizumi博士作出结论，“这种将细胞疗法与ROCK抑制物结合在一起的新策略最终可能在再生医学上提供一种新的治疗方法，不仅可以用来治疗角膜内皮功能障碍，也可用来治疗各种病理性疾病。”(生物谷：Bioon.com)
doi:10.1016/j.ajpath.2012.03.033
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ROCK Inhibitor Converts Corneal Endothelial Cells into a Phenotype Capable of Regenerating In Vivo Endothelial Tissue
Naoki Okumura, Noriko Koizumi, Morio Ueno, Yuji Sakamoto, Hiroaki Takahashi, Hideaki Tsuchiya, Junji Hamuro, Shigeru Kinoshita
Corneal endothelial dysfunction accompanied by visual disturbance is a primary indication for corneal transplantation. We previously reported that the adhesion of corneal endothelial cells (CECs) to a substrate was enhanced by the selective ROCK inhibitor Y-27632. It is hypothesized that the inhibition of ROCK signaling may manipulate cell adhesion properties, thus enabling the transplantation of cultivated CECs as a form of regenerative medicine. In the present study, using a rabbit corneal endothelial dysfunction model, the transplantation of CECs in combination with Y-27632 successfully achieved the recovery of corneal transparency. Complications related to cell injection therapy, such as the abnormal deposition of the injected cells as well as the elevation of intraocular pressure, were not observed. Reconstructed corneal endothelium with Y-27632 exhibited a monolayer hexagonal cell shape with a normal expression of function-related markers, such as ZO-1, and Na+/K+-ATPase, whereas reconstruction without Y-27632 exhibited a stratified fibroblastic phenotype without the expression of markers. Moreover, transplantation of CECs in primates in the presence of the ROCK inhibitor also achieved the recovery of long-term corneal transparency with a monolayer hexagonal cell phenotype at a high cell density. Taken together, these results suggest that the selective ROCK inhibitor Y-27632 enables cultivated CEC-based therapy and that the modulation of Rho-ROCK signaling activity serves to enhance cell engraftment for cell-based regenerative medicine.
