Bourne W M
Department of Ophthalmology, Mayo Clinic, Rochester, Minnesota, USA.
Trans Am Ophthalmol Soc. 1998;96:229-39; discussion 239-42.
To develop a technique to estimate the corneal endothelial pump rate in human subjects.
Corneal hydration control is thought to be maintained by a pump-leak mechanism whereby the leak of solutes and fluid across the endothelial barrier into the stroma is, in the steady state, exactly balanced by the pumping of solutes and passive fluid transfer across the endothelium to the aqueous humor. Overall corneal hydration control can be measured from the rate at which the swollen cornea thins (deswells), and a measure of the leak can be obtained simultaneously from the endothelial permeability to fluorescein. From the pump-leak hypothesis, the deswelling rate is directly proportional to the pump rate and inversely proportional to the leak rate. The relative endothelial pump rate can be estimated as the product of the normalized deswelling rate and the normalized endothelial permeability. This procedure was used to obtain the relative endothelial pump rate in 41 patients with diabetes mellitus, 12 patients with long-term corneal transplants, 20 long-term wearers of contact lenses, and 19 normal volunteer subjects after the short-term administration of topical dorzolamide.
The relative endothelial pump rate did not differ significantly from that of control subjects in diabetics, in contact lens wearers, and after dorzolamide administration, but was markedly decreased in the patients with corneal transplants, despite a reduction in permeability (reduced leak).
This method allows the estimation of both the barrier and pump arms of corneal endothelial function and should be useful in the investigation of causes and mechanisms of functional endothelial insufficiency.
开发一种估算人类受试者角膜内皮泵浦速率的技术。
角膜水合作用的控制被认为是通过一种泵 - 漏机制维持的，即溶质和液体通过内皮屏障漏入基质的过程，在稳态下，通过溶质的泵浦以及溶质和被动液体通过内皮向房水的转移而得到精确平衡。总体角膜水合作用的控制可以通过肿胀角膜变薄（消肿）的速率来测量，同时可以从内皮对荧光素的通透性获得漏出量的测量值。根据泵 - 漏假说，消肿速率与泵浦速率成正比，与漏出速率成反比。相对内皮泵浦速率可以估计为归一化消肿速率与归一化内皮通透性的乘积。使用该程序在局部给予多佐胺短期治疗后，获得了41例糖尿病患者、12例长期角膜移植患者、20例长期佩戴隐形眼镜者和19例正常志愿者受试者的相对内皮泵浦速率。
糖尿病患者、隐形眼镜佩戴者以及给予多佐胺后，相对内皮泵浦速率与对照受试者相比无显著差异，但角膜移植患者的相对内皮泵浦速率显著降低，尽管通透性降低（漏出减少）。
该方法可以估算角膜内皮功能的屏障和泵浦两个方面，在研究内皮功能不全的原因和机制方面应具有实用性。
