Purpose

Type 1 macular neovascularization (MNV) secondary to age-related macular degeneration (AMD) may sustain hypoxic and micronutrient-insufficient outer retinal cells compensatorily. We explored this hypothesis via histologic analysis of an eye with a shallow irregular retinal pigment epithelial elevation (SIRE) on OCT and good vision.

Design

Case study and clinicopathologic correlation.

Participant

A white woman with untreated nonexudative neovascular AMD and 20/30 visual acuity (left eye) and neovascular AMD (right eye), with 9 years’ multimodal imaging before dying at 90 years of age.

Methods

The left eye was preserved 6.25 hours after death and prepared for submicrometer epoxy resin sections and transmission electron microscopy aligned to clinical OCT B-scans. Inside and outside the MNV area, layer thicknesses, phenotypes, and vascular density of native choriocapillaris and neovessels were measured. Lengths of choriocapillaries and intervening gaps in the index eye and in early AMD eyes and healthy eyes with similar age (n = 19 each) from the Project MACULA (Maculopathy Unveiled by Laminar Analysis) online histopathologic resource (http://projectmacula.cis.uab.edu/) were measured with custom software (Caps and Gaps).

Main Outcome Measures

Descriptive features, vascular density, histologic and OCT layer thicknesses, and distribution of choriocapillaries and intervening gaps.

Results

The SIRE correlated to a type 1 MNV that expanded slowly without evidence of exudation and with numerous choroidal vessels traversing Bruch’s membrane defects, some visible on OCT. Tissue layers in and adjacent to the MNV area showed continuous RPE and characteristic AMD deposits. Capillary-like neovessels with fenestrations and caveolae resembling native choriocapillaris lined the retinal pigment epithelium (RPE) with a vascular density comparable with surrounding non-MNV areas. Relative to early AMD and healthy aged eyes, the index eye showed similar capillary lengths but larger gaps between vessels, indicating dropout. Outer nuclear layer thickness was preserved and showed less photoreceptor degeneration over areas of relative choriocapillaris health, including the type 1 MNV.

Conclusions

Eyes with nonexudative type 1 MNV in AMD may progress to exudation, yet this stable MNV complex supported outer retinal structure for 9 years. Distinguishing features were numerous connecting vessels, high density of neovessels, continuous RPE, and slow growth. Maintaining beneficial type 1 MNV may be a therapeutic strategy.

中文翻译：

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在年龄相关性黄斑变性中支持外视网膜的非排毒性黄斑新血管形成：临床病理相关性。

目的

继发于年龄相关性黄斑变性（AMD）的1型黄斑新生血管（MNV）可能维持缺氧和微量营养素不足的外部视网膜细胞补偿。我们通过组织学分析OCT和良好视力的浅浅不规则视网膜色素上皮升高（SIRE）的眼睛，探索了这一假设。

设计

案例研究与临床病理相关性。

参加者

一位白人妇女，未经治疗的非渗出性新血管性AMD，视敏度为20/30（左眼），新血管性AMD（右眼），经过9年的多模态成像，直到90岁去世。

方法

死后6.25小时保留左眼，并准备亚微米级环氧树脂切片和透射电子显微镜，以与临床OCT B扫描对准。在MNV区域的内部和外部，测量了天然脉络膜毛细血管和新血管的层厚度，表型和血管密度。在线组织病理学资源（MACULA）（层流分析揭示的巨斑病）在线组织病理学资源（http：//projectmacula.cis。）中，脉络膜毛细血管的长度以及食指，早期AMD眼和年龄相近的健康眼（n = 19）之间的间隙。 uab.edu/）使用自定义软件（上限和缺口）进行了测量。

主要观察指标

描述性特征，血管密度，组织学和OCT层厚度以及脉络膜毛细血管和中间间隙的分布。

结果

SIRE与1型MNV有关，该MNV缓慢扩张而没有渗出迹象，并且有许多脉络膜血管穿过Bruch的膜缺损，有些可见于OCT。MNV区域及其附近的组织层显示连续的RPE和特征性AMD沉积物。类似于天然脉络膜毛细血管的具有开孔和小窝的毛细血管样新血管排列在视网膜色素上皮（RPE）上，其血管密度与周围的非MNV区域相当。相对于早期AMD和健康的老年眼睛，食指的毛细血管长度相似，但血管之间的间隙较大，表明脱落。在相对脉络膜毛细血管健康的区域（包括1型MNV）上，外核层厚度得以保留并显示出较少的感光受体变性。

结论

AMD中具有非渗出性1型MNV的眼睛可能会发展为渗出，但是这种稳定的MNV复合体支持外部视网膜结构长达9年。显着特征是大量的连接血管，高密度的新血管，连续的RPE和缓慢的生长。维持有益的1型MNV可能是一种治疗策略。