Theoretical Analysis of Vascular Regulatory Mechanisms Contributing to Retinal Blood Flow Autoregulation
Theoretical Analysis of Vascular Regulatory Mechanisms Contributing to Retinal Blood Flow Autoregulation
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DOI：
10.1167/iovs.12-11543
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发表时间：
2013-08-01
影响因子：
4.4
通讯作者：
Guidoboni, Giovanna
中科院分区：
文献类型：
--
作者：
Arciero, Julia;Harris, Alon;Guidoboni, Giovanna
目的。为了研究视网膜自动调节受损是否是青光眼的危险因素，需要研究血管调节机制与青光眼进展之间的关系。在本研究中，血管壁力学模型用于预测调节机制在实现视网膜自动调节中的相对重要性。假设阻力血管对压力、剪切应力、二氧化碳 (CO2) 的变化以及通过传导响应传达的下游代谢状态做出反应。控制壁张力的模型参数适合猪视网膜小动脉的压力和直径数据。预测控制和升高 IOP 水平的自动调节压力范围。结果。当离开视网膜中央动脉的血压在 28 至 40 mm Hg 之间变化时，流量变化的因子用于指示自动调节的程度（1 表示完美的自动调节）。在仅存在生肌反应机制的情况下，该因子为 2.06。在存在肌源性反应和 CO2 反应的情况下，该因子为 1.22。肌源性、剪切力、CO2 和代谢反应的组合产生最佳的自动调节（因子 1.10）。结论。将模型结果与多个患者研究的流量和压力数据进行比较，预计代谢和二氧化碳反应的综合效应对于实现视网膜自动调节至关重要。当眼压升高时，该模型预测向低灌注压的自动调节范围会减小，这与青光眼与灌注压降低相关的观察结果一致。
PURPOSE. To study whether impaired retinal autoregulation is a risk factor for glaucoma, the relationship between vascular regulatory mechanisms and glaucoma progression needs to be investigated. In this study, a vascular wall mechanics model is used to predict the relative importance of regulatory mechanisms in achieving retinal autoregulation.METHODS. Resistance vessels are assumed to respond to changes in pressure, shear stress, carbon dioxide (CO2), and the downstream metabolic state communicated via conducted responses. Model parameters governing wall tension are fit to pressure and diameter data from porcine retinal arterioles. The autoregulation pressure range for control and elevated levels of IOP is predicted.RESULTS. The factor by which flow changes as the blood pressure exiting the central retinal artery is varied between 28 and 40 mm Hg is used to indicate the degree of autoregulation (1 indicates perfect autoregulation). In the presence of only the myogenic response mechanism, the factor is 2.06. In the presence of the myogenic and CO2 responses, the factor is 1.22. The combination of myogenic, shear, CO2, and metabolic responses yields the best autoregulation (factor of 1.10).CONCLUSIONS. Model results are compared with flow and pressure data from multiple patient studies, and the combined effects of the metabolic and CO2 responses are predicted to be critical for achieving retinal autoregulation. When IOP is elevated, the model predicts a decrease in the autoregulation range toward low perfusion pressure, which is consistent with observations that glaucoma is associated with decreased perfusion pressure.