The protective effect of DNase I in retinal vein occlusion.

Retinal vein occlusion (RVO) ranks as the second most prevalent retinal vascular disease, following diabetic retinopathy. Neutrophil extracellular traps (NETs) play an important role in vascular diseases. This study aimed to elucidate the relationship between NETs and RVO, and to discern the potential role of deoxyribonuclease I (DNase I) in the prevention and treatment of RVO through the modulation of NETs. We analyzed circulating NETs biomarkers, namely cell-free DNA (cf-DNA), myeloperoxidase (MPO)-DNA, and neutrophil elastase (NE), in 30 RVO patients and 30 healthy individuals. We established an RVO mouse model using a retinal laser, and the mice were categorized into two groups: the DNase I group and the control group. Retinal images were taken at predetermined time points, and the state of the retinal vessels was assessed. Both tissue and blood samples were harvested for analysis of NETs expression through methods such as western blotting, immunofluorescence staining, and enzyme-linked immunosorbent assay (ELISA). Our finding indicate an increase in circulating NETs biomarkers in human and mouse RVO cases, while also verifying the presence of NETs in the retinal thrombus of the RVO model. Both in vitro and in vivo tests revealed that DNase I attenuated NETs formation. Moreover, DNase I injections led to diminished NETs biomarker levels and a reduced duration of the thrombus after the RVO model establishment. Consequently, DNase I, a well-established modulator of NETs formation, might exhibit protective properties in the prevention and treatment of RVO.

Effects of Intravitreal Ranibizumab Injection on Peripheral Retinal Microcirculation and Cytokines in Branch Retinal Vein Occlusion with Macular Edema.

Background and Objectives: To investigate peripheral blood flow in retinal vessels and vessel diameters after intravitreal ranibizumab injection (IRI) and the relationship between these parameters and cytokines in branch retinal vein occlusion (BRVO) with macular edema. Materials and Methods: We assessed relative flow volume (RFV) and the width of the main and branch retinal arteries and veins in the occluded and non-occluded regions before and after IRI in 37 patients with BRVO and macular edema. Measurements were made using laser speckle flowgraphy (LSFG). When performing IRI, we obtained samples of aqueous humor and analyzed them using the suspension array method to evaluate vascular endothelial growth factor (VEGF), placental growth factor (PlGF), platelet-derived growth factor (PDGF)-AA, soluble intercellular adhesion molecule (sICAM)-1, monocyte chemoattractant protein 1 (MCP-1), interleukin (IL)-6, IL-8, and interferon-inducible 10-kDa protein (IP-10). Results: In both retinal regions, before and after IRI, the RFV in the main artery and vein showed a significant correlation with the summed RFV in the respective branch vessels 1 and 2. In the occluded region, the RFV in the main vein was significantly negatively correlated with MCP-1, PDGF-AA, IL-6, and IL-8; the RFV in branch vein 1 was significantly negatively correlated with PlGF, MCP-1, IL-6, and IL-8; PDGF-AA was significantly negatively correlated with the width of the main and branch veins; and the RFVs of the main artery and vein decreased significantly from before to 1 month after IRI. Conclusions: Contrary to expectations, the study found that anti-VEGF therapy does not affect RFV in arteries and veins in patients with BRVO and macular edema. Furthermore, retinal blood flow is poor in patients with high MCP-1, IL-6, and IL-8. Finally, high PDGF-AA may result in smaller venous diameters and reduced retinal blood flow.

Role of Novel Inflammatory Factors in Central Retinal Vein Occlusion with Macular Edema.

Background and Objectives: To investigate associations among the aqueous humor levels of novel inflammatory factors, including FMS-related tyrosine kinase 3 ligand (Flt-3L), fractalkine, CXC chemokine ligand 16 (CXCL-16), and endocan-1; the severity of macular edema in central retinal vein occlusion (CRVO); and the prognosis of CRVO with macular edema after antivascular endothelial growth factor (VEGF) therapy. Materials and Methods: Aqueous humor was obtained during anti-VEGF treatment with intravitreal ranibizumab injection (IRI) in patients with CRVO and macular edema (n = 19) and during cataract surgery in patients with cataracts (controls, n = 20), and the levels of VEGF and novel inflammatory factors were measured. Macular edema was evaluated by central macular thickness (CMT) and neurosensory retinal thickness (TNeuro), and improvement was evaluated by calculating the percentage change in CMT and TNeuro from before to 1 month after IRI. Results: The levels of VEGF and the novel inflammatory factors were significantly higher in the CRVO group, and the levels of Flt-3L, CXCL-16, and endocan-1 were significantly correlated with each other and with the aqueous flare value. Baseline levels of Flt-3L, CXCL-16, and endocan-1 had a significantly negative correlation with the change in CMT, and the baseline level of CXCL-16 was significantly negatively correlated with the change in TNeuro. Conclusions: Relations among novel inflammatory factors should be further investigated. These findings may help improve understanding of macular edema in CRVO patients and aid the development of new treatments targeting novel inflammatory factors.

Timolol maleate, a ß blocker eye drop, improved edema in a retinal vein occlusion model.

Purpose: To investigate the therapeutic effects of eye drops, namely, timolol maleate, a ß-adrenergic receptor antagonist, and latanoprost, a prostaglandin F2α analog, on retinal edema in a murine retinal vein occlusion (RVO) model. Methods: An RVO model was established using laser-induced RVO in mice, which were administered timolol maleate and latanoprost eye drops several times after venous occlusion. Subsequently, the thickness of the inner nuclear layer (INL) and the expression levels of such genes as Vegf and Atf4, which are stress markers of the endoplasmic reticulum, were examined. Primary human cultured retinal microvascular endothelial cells (HRMECs) were treated with timolol under hypoxic conditions, after which the gene expression pattern was investigated. Importantly, an integrated stress response inhibitor (ISRIB) was used in the RVO model, he known ISRIB, which suppresses the expression of ATF4 in retinal edema. Results: Increased INL thickness was suppressed by timolol eye drops, as were the expressions of Vegf and Atf4, in the RVO model. However, latanoprost eye drops did not induce any change in INL thickness. In HRMECs, hypoxic stress and serum deprivation increased the Vegf and Atf4 expressions; in response, treatment with timolol suppressed the Vegf expression. Furthermore, the ISRIB decreased the Vegf expression pattern and edema formation, which are associated with RVO. Conclusions: These results indicate that timolol eye drops may be a potential option for RVO treatment.

Neurovascular injury associated non-apoptotic endothelial caspase-9 and astroglial caspase-9 mediate inflammation and contrast sensitivity decline.

Retinal neurovascular injuries are a leading cause of vision loss in young adults presenting unmet therapeutic needs. Neurovascular injuries damage homeostatic communication between endothelial, pericyte, glial, and neuronal cells through signaling pathways that remain to be established. To understand the mechanisms that contribute to neuronal death, we use a mouse model of retinal vein occlusion (RVO). Using this model, we previously discovered that after vascular damage, there was non-apoptotic activation of endothelial caspase-9 (EC Casp9); knock-out of EC Casp9 led to a decrease in retinal edema, capillary ischemia, and neuronal death. In this study, we aimed to explore the role of EC Casp9 in vision loss and inflammation. We found that EC Casp9 is implicated in contrast sensitivity decline, induction of inflammatory cytokines, and glial reactivity. One of the noted glial changes was increased levels of astroglial cl-caspase-6, which we found to be activated cell intrinsically by astroglial caspase-9 (Astro Casp9). Lastly, we discovered that Astro Casp9 contributes to capillary ischemia and contrast sensitivity decline after RVO (P-RVO). These findings reveal specific endothelial and astroglial non-apoptotic caspase-9 roles in inflammation and neurovascular injury respectively; and concomitant relevancy to contrast sensitivity decline.

Alteration of plasma von Willebrand factor in the treatment of retinal vein occlusion with cystoid macular edema.

Retinal vein occlusion (RVO) is a major retinal disease caused by venous thrombosis. Although several studies have proposed an association between venous thrombosis and von Willebrand factor (VWF), the association between RVO and VWF remains unclear. We aimed to investigate the association between RVO and VWF and the alteration of VWF levels under anti-vascular endothelial growth factor (VEGF) treatment. We enrolled 55 patients with RVO involved cystoid macular edema. They received intravitreal injection of anti-VEGF drugs, either ranibizumab or aflibercept. We examined the clinical data and measured plasma VWF antigen and a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS13) activity to identify variabilities during treatment. At baseline, there was no significant difference between the RVO group and age-matched controls in both VWF antigen and ADAMTS13 activity levels, but ADAMTS13 activity was significantly lower in central RVO than in branch RVO (P = 0.015). In branch RVO, VWF antigen was negatively correlated with central choroidal thickness (r = -0.51, P < 0.001). In branch RVO after anti-VEGF treatment, VWF antigen levels decreased significantly from 134% at baseline to 109% at 1 day (P = 0.002) and 107% at 1 month (P = 0.030) after treatment. In contrast, ADAMTS13 activity showed no significant difference during this period. In branch RVO at 1 month after treatment, VWF antigen was negatively correlated with central choroidal thickness (r = -0.47, P = 0.001). Our findings suggest an association between VWF and central choroidal thickness in patients with branch RVO, thus the measurement of VWF may be useful for evaluating disease activity and prognosis.

Differential expression of aqueous humor microRNAs in central retinal vein occlusion and its association with matrix metalloproteinases: a pilot study.

The aim of this study is to investigate the differential expression of microRNAs (miRNAs) in the aqueous humor (AH) of patients with central retinal vein occlusion (CRVO), and their association with AH matrix metalloproteinase (MMP) activity. Eighteen subjects, including 10 treatment naïve patients with CRVO and 8 control subjects, scheduled for intravitreal injection and cataract surgery, respectively, were included. AH samples were collected at the beginning of the procedure. A microarray composed of 84 miRNAs was performed to identify differentially expressed miRNAs in CRVO AH, which were further analyzed using bioinformatic tools to identify directly related cytokines/proteins. Eight miRNAs (hsa-mir-16-5p, hsa-mir-142-3p, hsa-mir-19a-3p, hsa-mir-144-3p, hsa-mir-195-5p, hsa-mir-17-5p, hsa-mir-93-5p, and hsa-mir-20a-5p) were significantly downregulated in the CRVO group. Bioinformatic analysis revealed a direct relationship among downregulated miRNAs, CRVO, and the following proteins: MMP-2, MMP-9, tumor necrosis factor, transforming growth factor beta-1, caspase-3, interleukin-6, interferon gamma, and interleukin-1-beta. Activities of MMP-2 and -9 in AH were detected using gelatin zymography, showing significant increase in the CRVO group compared to the control group (p < 0.01). This pilot study first revealed that MMP-2 and -9 were directly related to downregulated miRNAs and showed significant increase in activity in AH of patients with CRVO. Therefore, the relevant miRNAs and MMPs in AH could serve as potential biomarkers or therapeutic targets for CRVO.

Dexamethasone Intravitreal Implant Is Active at the Molecular Level Eight Weeks after Implantation in Experimental Central Retinal Vein Occlusion.

Central retinal vein occlusion (CRVO) is a visually disabling condition resulting from a thrombus in the major outflow vessel of the eye. The inflammatory response in CRVO is effectively treated with a dexamethasone (DEX) intravitreal implant. Uncovering the proteome changes following DEX implant intervention in CRVO may identify key proteins that mediate the beneficial effects of DEX. In six Göttingen minipigs, CRVO was induced in both eyes with an argon laser using a well-established experimental model. The right eyes were treated with a DEX intravitreal implant (Ozurdex, Allergan), while the left control eyes received a sham injection. Eight weeks after DEX intervention, retinal samples were collected and analyzed with tandem mass tag-based mass spectrometry. DEX implant intervention resulted in the upregulation of peptidyl-prolyl cis-trans isomerase FKBP5 (FKBP5) and ubiquilin-4. Immunohistochemistry showed expression of FKBP5 in the nuclei in all cellular layers of the retina. Cell adhesion molecule 3, tumor necrosis factor receptor superfamily member 16, and trans-1,2-dihydrobenzene-1,2-diol dehydrogenase were downregulated following DEX intervention. The upregulation of the corticosteroid-sensitive protein FKBP5 suggests that the implant remained active at the molecular level after eight weeks of treatment. Future studies may investigate if FKBP5 regulates the efficacy and duration of the DEX implant.

Efficacy of an Anti-Semaphorin 3A Neutralizing Antibody in a Male Experimental Retinal Vein Occlusion Mouse Model.

Purpose: Semaphorin 3A (Sema3A) is a promising therapeutic target for macular edema in age-related macular degeneration, diabetic retinopathy, and retinal vein occlusion (RVO). Anti-vascular endothelial growth factors (anti-VEGFs) are the current standard of care for many retinal diseases. This study investigated the Sema3A neutralizing antibody BI-X and/or anti-VEGF therapy (aflibercept) in an RVO mouse model. Treatment efficacy was examined and grouped by timing subsequent to the RVO mouse model induction: efficacy against the onset of intraretinal edema 1 day postinduction and protective effects at 7 days postinduction. Methods: We examined the changes in expression of Sema3A in the retina of an RVO mouse model. In addition, changes in expression of tumor necrosis factor (TNF)-α and semaphorin-related proteins (neuropilin-1 and plexin A1) in the retina upon treatment were analyzed by Western blotting. The effects of BI-X and/or aflibercept were evaluated using measures of retinal edema, blood flow, and thinning of the inner nuclear layer. Results: Induction of vein occlusion in the RVO mouse model significantly increased Sema3A expression in the retina, particularly in the inner nuclear layer. BI-X was effective as a monotherapy and in combination with anti-VEGF therapy, demonstrating a beneficial effect on intraretinal edema and retinal blood flow. Moreover, in the RVO mouse model, BI-X monotherapy normalized the changes in expression of TNF-α and semaphorin-related proteins. Conclusions: These findings support targeting Sema3A to treat intraretinal edema and retinal ischemia.

Proteome Analysis of Aflibercept Intervention in Experimental Central Retinal Vein Occlusion.

Aflibercept is a frequently used inhibitor of vascular endothelial growth factor (VEGF) in the treatment of macular edema following central retinal vein occlusion (CRVO). Retinal proteome changes following aflibercept intervention in CRVO remain largely unstudied. Studying proteomic changes of aflibercept intervention may generate a better understanding of mechanisms of action and uncover aspects related to the safety profile. In 10 Danish Landrace pigs, CRVO was induced in both eyes with an argon laser. Right eyes were treated with intravitreal aflibercept while left control eyes received isotonic saline water. Retinal samples were collected 15 days after induced CRVO. Proteomic analysis by tandem mass tag-based mass spectrometry identified a total of 21 proteins that were changed in content following aflibercept intervention. In retinas treated with aflibercept, high levels of aflibercept components were reached, including the VEGF receptor-1 and VEGF receptor-2 domains. Fold changes in the additional proteins ranged between 0.70 and 1.19. Aflibercept intervention resulted in a downregulation of pigment epithelium-derived factor (PEDF) (fold change = 0.84) and endoplasmin (fold change = 0.91). The changes were slight and could thereby not be confirmed with less precise immunohistochemistry and Western blotting. Our data suggest that aflibercept had a narrow mechanism of action in the CRVO model. This may be an important observation in cases when macular edema secondary to CRVO is resistant to aflibercept intervention.

The Changes of Irisin and Inflammatory Cytokines in the Age-Related Macular Degeneration and Retinal Vein Occlusion.

Purpose: Age-related macular degeneration (AMD) and retinal vein occlusion (RVO) are irreversible chorioretinal diseases, which might induce severe damage in visual function. The metabolic factor and inflammatory factors might play important roles in the pathogenesis of AMD and RVO. The levels of irisin and 14 cytokines were analyzed in aqueous humor of AMD and RVO eyes to evaluate the roles of irisin and inflammatory factors. Methods: We collected aqueous humor samples from patients with AMD (n = 27), RVO (n = 30), and cataract (as control, n = 23) eyes. Samples were assayed using ELISA kit for irisin and a multiplex immunoassay kit for 14 cytokines. The macular thickness (MT) was measured with OCT in all included eyes. Results: MT in the RVO group is significantly higher than that in the AMD or control group. Irisin levels in the aqueous samples of AMD and RVO eyes were both significantly lower than that in the control. Furthermore, a positive correlation was found between irisin and MT in the RVO. Compared with the controls, AMD eyes had significantly higher levels of BDNF, VEGF-A, VEGF-R1, VEGF-R2, IL-10, TNF-α, VCAM-1, IP-10, and MCP-1. Similarly, RVO eyes had significantly higher levels of BDNF, VEGF-A, VEGF-R1, VEGF-R2, IL-6, IL-8, IL-10, TNF-α, ICAM-1, VCAM-1, IP-10, and MCP-1. However, there was no significant difference between the levels of PDGF-BB or TNF-ß in these three groups. A negative correlation was found between VEGF-A and MT in AMD, as well as in control. Furthermore, a positive correlation was found between IL-6 and MT in the 80 included eyes, as well as in RVO. A positive correlation was found between ICAM-1 and MT in the 80 included eyes, as well as in RVO. Conclusions: The metabolic factor, irisin levels in the aqueous humor are decreased in AMD and RVO eyes and show a positive correlation between irisin and MT in RVO eyes, prompting researchers to explore the relationship between irisin and macular edema. We also identified the higher expression of vascular growth factors (VEGF-A, VEGF-R1, and PDGF-BB), inflammatory cytokines (IL-6, IL-8, IL-10, and TNF-α), and chemokines (ICAM-1, VCAM-1, IP-10, and MCP-1) in AMD and RVO eyes.

Automated quantification of macular fluid in retinal diseases and their response to anti-VEGF therapy.

AIM: To objectively assess disease activity and treatment response in patients with retinal vein occlusion (RVO), neovascular age-related macular degeneration (nAMD) and centre-involved diabetic macular oedema (DME), using artificial intelligence-based fluid quantification. METHODS: Posthoc analysis of 2311 patients (11 151 spectral-domain optical coherence tomography volumes) from five clinical, multicentre trials, who received a flexible antivascular endothelial growth factor (anti-VEGF) therapy over a 12-month period. Fluid volumes were measured with a deep learning algorithm at baseline/months 1, 2, 3 and 12, for three concentric circles with diameters of 1, 3 and 6 mm (fovea, paracentral ring and pericentral ring), as well as four sectors surrounding the fovea (superior, nasal, inferior and temporal). RESULTS: In each disease, at every timepoint, most intraretinal fluid (IRF) per square millimetre was present at the fovea, followed by the paracentral ring and pericentral ring (p<0.0001). While this was also the case for subretinal fluid (SRF) in RVO/DME (p<0.0001), patients with nAMD showed more SRF in the paracentral ring than at the fovea up to month 3 (p<0.0001). Between sectors, patients with RVO/DME showed the highest IRF volumes temporally (p<0.001/p<0.0001). In each disease, more SRF was consistently found inferiorly than superiorly (p<0.02). At month 1/12, we measured the following median reductions of initial fluid volumes. For IRF: RVO, 95.9%/97.7%; nAMD, 91.3%/92.8%; DME, 37.3%/69.9%. For SRF: RVO, 94.7%/97.5%; nAMD, 98.4%/99.8%; DME, 86.3%/97.5%. CONCLUSION: Fully automated localisation and quantification of IRF/SRF over time shed light on the fluid dynamics in each disease. There is a specific anatomical response of IRF/SRF to anti-VEGF therapy in all diseases studied.

Role of the choroidal vascularity index in branch retinal vein occlusion (BRVO) with macular edema.

PURPOSE: To assess choroidal vasculature changes in eyes with branch retinal vein occlusion (BRVO) and macular edema (ME) using the choroidal vascularity index (CVI) and evaluate the effectiveness of CVI as a prognostic biomarker. METHODS: 35 patients with monocular BRVO and ME were analyzed retrospectively. Luminal and stromal areas in choroids of swept-source optical coherence tomography were calculated using the image binarization technique. The CVI was calculated as the ratio of the luminal to total choroidal area. The CVI of BRVO and ME eyes were compared with that of the unaffected fellow and post anti-vascular endothelial growth factor (VEGF) injected eyes. A regression analysis was performed on the choroidal parameters, logMAR visual acuity (VA) two years post disease onset and central macula thickness (CMT). RESULTS: The CVI of BRVO and ME eyes was significantly lower than the fellow and post-injected eyes (p<0.05). The regression analysis showed a strong association between two years after logMAR VA and the CVI of fellow eyes (R2 = 0.433, p<0.001). Remarkable correlations were observed in the CVI and subfoveal choroidal thickness of BRVO and ME eyes (R2 = 0.189, 0.155, respectively, p<0.05). The CMT of diseased eyes were also significantly associated with the CVI of unaffected fellow eyes (R2 = 0.113, p<0.05). CONCLUSIONS: The alteration of CVI in BRVO and ME suggests that choroidal vasculature might be affected by extracellular fluid shift and VEGF changes. The fellow eye CVI could be a useful supplementary prognostic biomarker.

Peripapillary retinal nerve fiber layer thickness in patients with unilateral retinal vein occlusion.

This study evaluated longitudinal changes in peripapillary retinal nerve fiber layer (pRNFL) thickness in eyes affected with branch and central retinal vein occlusion (BRVO and CRVO, respectively) and fellow eyes. This retrospective case-control study included patients with newly diagnosed unilateral BRVO (46 patients) or unilateral CRVO (27 patients). The control group included 48 patients without abnormal findings on the fundus examination. Global and all-sector pRNFL thicknesses were greater in eyes with BRVO and CRVO than in fellow eyes at baseline; however, at 24 months, this difference remained only in the temporal sector of eyes affected with CRVO. Although the global pRNFL thicknesses of the fellow eyes in the BRVO and CRVO groups decreased significantly at 24 months compared to baseline (p = 0.001 and p = 0.011, respectively), there was no significant difference in the normal control group (p = 0.824). The global, inferior temporal, and inferior nasal pRNFL thicknesses at 12 and 24 months were significantly lower in the fellow eyes of the CRVO group than in those of the BRVO and normal control groups. The fellow eyes of patients with BRVO and CRVO suffered a significant reduction in pRNFL thickness compared to normal controls, indicating that they are susceptible to pRNFL damage.

Significant elevation of aqueous endothelin-1 in central retinal vein occlusion.

PURPOSE: To investigate aqueous humor concentrations of endothelin-1 (ET-1) in patients with central retinal vein occlusion (CRVO) compared with patients with branch retinal vein occlusion (BRVO) and a normal control group. METHODS: A total 80 subjects were included in this prospective study, including 15 patients with CRVO, 20 patients with BRVO, and 45 patients who underwent cataract surgery and had no concomitant ocular disease. Aqueous humor levels of ET-1 were obtained before intravitreal bevacizumab injection (IVB) and after 1 month. RESULTS: At baseline, the mean aqueous ET-1 level was 12.7±3.6 pg/mL in the CRVO group, 8.0±2.3 pg/mL in the BRVO group, and 2.0±0.9 pg/mL in the control group (P<0.001). After IVB, the mean aqueous level of ET-1 was 3.4±1.9 pg/mL (0.5-6.9 pg/mL) in the CRVO group and 1.8±1.0 pg/mL (0.3-3.2 pg/mL) in the BRVO group (P = 0.008). The mean aqueous ET-1 level was significantly reduced in both the patients with CRVO and those with BRVO (P<0.001). CONCLUSION: The mean aqueous humor ET-1 level was significant higher in the patients with CRVO than those with BRVO and in the control group. After IVB, the mean level was significantly reduced in both the patients with CRVO and those with BRVO.

Anti-VEGF-Resistant Retinal Diseases: A Review of the Latest Treatment Options.

Anti-vascular endothelial growth factor (anti-VEGF) therapy currently plays a central role in the treatment of numerous retinal diseases, most notably exudative age-related macular degeneration (eAMD), diabetic retinopathy and retinal vein occlusions. While offering significant functional and anatomic benefits in most patients, there exists a subset of 15-40% of eyes that fail to respond or only partially respond. For these cases, various treatment options have been explored with a range of outcomes. These options include steroid injections, laser treatment (both thermal therapy for retinal vascular diseases and photodynamic therapy for eAMD), abbreviated anti-VEGF treatment intervals, switching anti-VEGF agents and topical medications. In this article, we review the effectiveness of these treatment options along with a discussion of the current research into future directions for anti-VEGF-resistant eyes.

Vascular Patterning as Integrative Readout of Complex Molecular and Physiological Signaling by VESsel GENeration Analysis.

The molecular signaling cascades that regulate angiogenesis and microvascular remodeling are fundamental to normal development, healthy physiology, and pathologies such as inflammation and cancer. Yet quantifying such complex, fractally branching vascular patterns remains difficult. We review application of NASA's globally available, freely downloadable VESsel GENeration (VESGEN) Analysis software to numerous examples of 2D vascular trees, networks, and tree-network composites. Upon input of a binary vascular image, automated output includes informative vascular maps and quantification of parameters such as tortuosity, fractal dimension, vessel diameter, area, length, number, and branch point. Previous research has demonstrated that cytokines and therapeutics such as vascular endothelial growth factor, basic fibroblast growth factor (fibroblast growth factor-2), transforming growth factor-beta-1, and steroid triamcinolone acetonide specify unique "fingerprint" or "biomarker" vascular patterns that integrate dominant signaling with physiological response. In vivo experimental examples described here include vascular response to keratinocyte growth factor, a novel vessel tortuosity factor; angiogenic inhibition in humanized tumor xenografts by the anti-angiogenesis drug leronlimab; intestinal vascular inflammation with probiotic protection by Saccharomyces boulardii, and a workflow programming of vascular architecture for 3D bioprinting of regenerative tissues from 2D images. Microvascular remodeling in the human retina is described for astronaut risks in microgravity, vessel tortuosity in diabetic retinopathy, and venous occlusive disease.

AQUEOUS HUMOR CYTOKINE LEVELS AND REBOUND MACULAR EDEMA AFTER CONBERCEPT TREATMENT IN PATIENTS WITH CENTRAL RETINAL VEIN OCCLUSION.

PURPOSE: This study aimed to investigate the effect of intravitreal conbercept (IVC) injections on the aqueous humor concentrations of angiogenic and inflammatory cytokines in patients with macular edema (ME) due to central retinal vein occlusion and to determine whether changes in cytokine levels after IVC are associated with the development of rebound ME. METHODS: Forty-nine patients with ME caused by central retinal vein occlusion were included in this retrospective study. Monthly doses of IVC were administered for three months, followed by a Pro Re Nata dosing regimen. Rebound ME was defined as ≥110% increase in the foveal thickness compared with the baseline. Whenever injections were administered, aqueous humor samples were obtained. Multiplex bead assay was used to measure seven angiogenic and inflammatory cytokines in aqueous humor samples. RESULTS: At baseline, patients with central retinal vein occlusion showed significantly higher aqueous humor concentrations of vascular endothelial growth factor, placental growth factor, monocyte chemoattractant protein-1, platelet-derived growth factor-AA, IL-6, IL-8, and IL-12. At 1-month and 2-month follow-up after IVC, significantly decreased concentrations of all cytokines were observed. During the 12-month follow-up period, 6 of the 49 eyes (12.2%) showed rebound ME after IVC. Patients with rebound ME showed significantly elevated levels of inflammatory but not angiogenic cytokines. CONCLUSION: Angiogenic and inflammatory cytokines were overexpressed in patients with ME caused by central retinal vein occlusion. Conbercept treatment influenced the concentrations of various inflammatory cytokines and reduced aqueous vascular endothelial growth factor and placental growth factor concentrations. Rebound ME may occur due to disruption of the balance between angiogenic and inflammatory cytokines and an accompanying excess of inflammatory cytokines but not angiogenic cytokines, after antivascular endothelial growth factor therapy.

Retinal oximetry does not predict 12-month visual outcome after anti-VEGF treatment for central retinal vein occlusion: A multicentre study.

PURPOSE: Central retinal vein occlusion (CRVO) entails retinal hypoxia that often causes visual impairment. It has been shown that oxygen saturation in larger retinal vessels correlates with the visual acuity at the time of diagnosis of CRVO but has no predictive value for the visual outcome in patients treated with anti-VEGF medication after 3 months. However, assessing the predictive value of retinal oxygen saturation after 12 months is essential because this is when the main restitution after CRVO occurs. METHODS: Retinal oximetry was performed in 117 patients referred with CRVO to three European centres. The correlation between oxygen saturation and visual acuity at baseline and the predictive value of oxygen saturation in larger retinal vessels for the 12-month visual outcome after treatment with anti-VEGF medication were studied. RESULTS: In the affected eye, the oxygen saturation was significantly higher in the arterioles, significantly lower in the venules, and the arterio-venous (A-V) significantly higher than in the unaffected eye (p < 0.001 for all comparisons). Correlations between best-corrected visual acuity (BCVA) and oxygen saturations were moderate and negative for arterioles (p < 0.001), positive for venules (p = 0.03) and negative for the A-V difference (p = 0.001). Best-corrected visual acuity (BCVA), but not oxygen saturation or the other explanatory variables at baseline, contributed significantly to predicting BCVA after 12 months. CONCLUSION: Retinal vessel oxygen saturation is affected in CRVO, and saturation correlates with BCVA. However, retinal oximetry cannot replace measures of visual function as a predictor of visual outcome after 12 months of anti-VEGF treatment for CRVO.