Increased Macrophage-like Cell Density in Retinal Vein Occlusion as Characterized by en Face Optical Coherence Tomography

Abstract

Objectives: to quantitatively analyze macrophage-like cells (MLCs) at the vitreoretinal interface in retinal vein occlusion (RVO) using swept-source optical coherence tomography angiography (SS-OCTA) and en face optical coherence tomography (OCT). Methods: The study included 72 RVO patients, with 43 acute patients and 29 chronic patients. For a normal control, 64 fellow eyes were included. MLCs were visualized in a 5 μm en face OCT slab above the vitreoretinal interface centered on the fovea. After semi-automatic binarization and quantification, we evaluated the MLC count and density among groups. We also investigated the MLC density and distribution relative to retinal edema. Results: Morphological changes and congregation of MLCs appeared in RVO eyes. The MLC density of both the acute and chronic groups was significantly higher than that of the control eyes (p < 0.001). In the acute group, the MLC density of the edematous region was lower than both the non-edematous region (p < 0.001) and the whole image (p < 0.01). The MLC density in acute eyes was negatively correlated to central fovea thickness (CFT) (r = −0.352, p < 0.05). The MLC density in chronic eyes was positively correlated to CFT and mean retina thickness (MRT) (r = 0.406, p < 0.05; r = 0.412, p < 0.05, respectively). Conclusions: SS-OCTA is a viable and simple method for the characterization of MLCs at the vitreoretinal interface. A significant increase in the MLC density in both acute and chronic eyes implicates the activation and recruitment of MLCs in RVO and that the MLC density and distribution can be affected by retinal edema.

Macrophage-like Cells Are Increased in Retinal Vein Occlusion and Correlate with More Intravitreal Injections and Worse Visual Acuity Outcomes

“…Since PDR shares many pathophysiologic features with RVO, including ischemia and inflammation, we hypothesized that MLCs are more numerous in RVO eyes. In agreement, Zeng et al and Wang et al recently showed that MLC density was significantly increased in RVO eyes [ 21 , 22 ]. However, Zeng et al did not investigate if MLCs can predict meaningful RVO outcomes.…”

“…However, Zeng et al did find that MLC density significantly correlated with increased macular thickness, which we did not observe [ 21 ]. Similarly, Wang et al observed a positive correlation between MLC density and macular thickness in chronic eyes, but a negative association in acute eyes [ 22 ]. Since our study investigated a cross-sectional population including both acute and chronic eyes, we did not find an association between MLCs and baseline CST because the acute and chronic patients have inverse associations, canceling out each another.…”

“…To our knowledge, Zeng et al and Wang et al are the only other published studies that investigated MLCs in RVO eyes [ 21 , 22 ]. Our results support those studies in that we also found MLC density and percent area were significantly higher in RVO eyes compared to control eyes.…”

Proliferative diabetic retinopathy and diabetic macular edema are two factors that increase macrophage-like cell density characterized by en face optical coherence tomography

“…In the current study, our finding, that MLC density increased a lot in eyes with DME, is consistent with previous experimental results and provide clinical evidence that macrophage/microglia may participate in DME pathological process. Our previous study in retinal vein occlusion also showed that MLC density correlated positively with retina thickness in chronic patients [ 19 ]. Another interesting result is that the positive correlation between MLC density and retinal thickness was established only in NPDR group.…”

Quantifying Putative Retinal Gliosis in Preclinical Alzheimer's Disease

“… 44 – 47 Putative retinal gliosis (activated retinal astrocytes, microglia, and Müller cells) has been quantitatively characterized as hyper-reflective patches on SD-OCT en face images that correspond to similar structures on the b-scans in glaucoma, 45 , 48 – 50 diabetic retinopathy, 51 – 53 and retinal vein occlusion. 54 The presence of these hyper-reflective structures (putative gliotic changes) and the extent of retinal region covered with them have been reported to have a greater potential of being an indicator for glaucomatous degeneration. 45 These areas of putative gliosis are also increased in proliferative diabetic retinopathy compared to nonproliferative and control participants, with patients with diabetic macular edema having larger areas compared to patients with no macular edema.…”