Panagis Lampros, Basile Maria, Friedman Alan H, Danias John
Department of Ophthalmology, Mount Sinai School of Medicine, New York, NY 10029, USA.
Arch Ophthalmol. 2010 Nov;128(11):1437-41. doi: 10.1001/archophthalmol.2010.243.
To understand the role of the α(1A)-adrenoreceptors (ARs) in the pathophysiologic mechanism of intraoperative floppy iris syndrome (IFIS).
Iris specimens from a patient with tamsulosin hydrochloride-induced IFIS were obtained during trabeculectomy. Specimens underwent histological analysis and immunohistochemical analysis with antibodies specific for actin, myoglobin, α(1A)-ARs, and myosin. Iris specimens from a patient without IFIS were used for comparison. Samples were processed for transmission electron microscopy.
Histological examination showed normal dilator muscle, arterioles, stroma, and pigment epithelium. Actin, myosin, and myoglobin distribution and intensities were similar between IFIS and non-IFIS tissue. The staining pattern and colocalization with myosin suggested that α(1A)-ARs are present in iris arteriolar muscularis in addition to the dilator muscle in both IFIS and control irides. Significantly less staining of IFIS tissue was found compared with the non-IFIS iris. Ultrastructures of melanocytes and stroma appeared to be normal. Iris arterioles possessed thick endothelial basement membranes, semilongitudinally oriented muscularis, and abundant perivascular collagen coats.
We confirm the presence of α(1A)-ARs in human iris by results of immunohistochemical analysis. The α(1A)-ARs localize to iris arteriolar muscularis in addition to the iris dilator muscle. This localization suggests that IFIS may develop because of iris vascular dysfunction and that iris vasculature may have structural in addition to nutritive functions.
了解α(1A)-肾上腺素能受体（ARs）在术中虹膜松弛综合征（IFIS）病理生理机制中的作用。
在小梁切除术期间获取一名因盐酸坦索罗辛诱发IFIS患者的虹膜标本。标本进行组织学分析以及使用针对肌动蛋白、肌红蛋白、α(1A)-ARs和肌球蛋白的特异性抗体进行免疫组织化学分析。使用一名无IFIS患者的虹膜标本作为对照。样本进行透射电子显微镜检查。
组织学检查显示瞳孔开大肌、小动脉、基质和色素上皮正常。IFIS组织和非IFIS组织之间肌动蛋白、肌球蛋白和肌红蛋白的分布及强度相似。染色模式以及与肌球蛋白的共定位表明，在IFIS虹膜和对照虹膜中，除瞳孔开大肌外，α(1A)-ARs也存在于虹膜小动脉肌层。与非IFIS虹膜相比，IFIS组织的染色明显减少。黑素细胞和基质的超微结构似乎正常。虹膜小动脉具有厚的内皮基底膜、半纵向排列的肌层以及丰富的血管周围胶原被膜。
我们通过免疫组织化学分析结果证实人虹膜中存在α(1A)-ARs。α(1A)-ARs除了定位于虹膜瞳孔开大肌外，还定位于虹膜小动脉肌层。这种定位表明IFIS可能因虹膜血管功能障碍而发生，并且虹膜血管系统可能除了营养功能外还具有结构功能。
