Retinal Neovascularization Research Articles

Multimodal imaging features of retinal neovascularization in response to 3 anti-VEGF injections

ObjectiveTo analyze longitudinal changes of retinal neovessels (NV) in eyes with proliferative diabetic retinopathy (PDR) after 3 monthly intravitreal injections (IVI) of ranibizumab by means of different imaging modalities, particularly focusing on optical coherence tomography (OCT) and OCT–angiography (OCT-A) features. MethodsProspective, monocentric study, Luigi Sacco Hospital, Milan. Consecutive patients with PDR were enrolled. All patients underwent color fundus photography (CFP), fluorescein angiography (FA), SD-OCT, and OCT-A at baseline (t0) and after 3 monthly IVI of ranibizumab (t1). Neovessels (NVs) were classified as flat, elevated, flat-elevated, or table-top using OCT scans and further analyzed on FIJI. Qualitative and quantitative NV characteristics were evaluated. Vessel density (VD) was calculated as the mean of all the white pixels of the NV and expressed as a percentage of the area of the NV (VD = NV area × 100). ResultsThirty-six NVs in 10 patients were studied. The regression of NVs at t1 was partial in 66.7% of cases and complete in 33.3%. Table-top NV demonstrated more frequently a complete regression (P = .03). A significant reduction of the NV area, perimeter, and VD was observed at t1 (P < .001). NVs that showed a complete regression had higher mean VD values at t0 compared with NVs, which showed a partial regression (P = .02). Flat NVs had more frequently a complete vitreous attachment, while table-top showed more often a partial vitreous detachment with focal NV adhesion (P < .05). A complete regression was more often observed for NVs with a partial vitreous detachment and focal NV adhesion at t0 (10/12), while most of the NVs with a complete vitreous attachment showed a partial regression (18/24) (P < .001). ConclusionsThe table-top configuration of the neovessel, higher VD values at baseline, and the presence of a focal adhesion of the vitreous over the NV were factors associated with a higher risk of complete regression of the NV in response to 3 monthly IVI of ranibizumab.

Regulation of the HMGA2-SNAI2/CXCR4 axis in atherosclerosis and retinal neovascularization: new therapeutic insights.

Atherosclerosis (AS) is a vascular disease associated with endothelial damage, plaque formation, and retinal neovascularization (RNV), leading to visual impairment. Research indicates that vascular endothelial dysfunction, lipid deposition, and inflammatory responses contribute to the formation of plaques and atherosclerotic lesions. Among the common complications, studies have shown that RNV and the molecular mechanisms of AS hold significant clinical importance. In this study, we identified the overexpression of the gene heat shock protein 90 (HSP90) through transcriptome sequencing. Subsequent protein expression analysis and inhibition experiments in corresponding animal models confirmed the crucial role of HSP90 in the modulation of this disease. Research findings revealed an increase in the expression of HSP90, HMGA2, Snail family transcriptional repressor 2 gene (SNAI2), CXC chemokine receptor 4 (CXCR4), and vascular endothelial growth factor (VEGF) in atherosclerotic mouse tissues. Inhibition of HSP90 expression reduced vascular neovascularization and downregulated the expression of HMGA2 and VEGF. Given that HSP90 can promote HMGA2 expression, which, in turn, facilitates angiogenesis, we conducted lentiviral infection experiments on primary retinal endothelial cells obtained from atherosclerotic mice, confirming the regulatory role of HSP90 in modulating HMGA2 expression through the SNAI2/CXCR4 signaling pathway and its involvement in retinal endothelial neovascularization. In conclusion, our study highlights the significant regulatory role of HSP90 in AS-induced RNV, providing a new target for disease treatment. Furthermore, this research extensively explores the mechanism of HSP90 in regulating RNV and associated signaling pathways, offering novel insights and laying a solid foundation for future studies in this disease domain.

SN promote retinal pathological neovascularization through activation of EGFR, IR and IGF-1R

Secretoneurin (SN) is a neuropeptide derived from secretogranin II (SgII), mainly are involved in neuroendocrine system. The present study is aimed to investigate the role of SN in retinal pathological neovascularization and physiological vasculature. In the study, we found the overexpression of SgII in retina of Oxygen-Induced Retinopathy (OIR) mouse model, and SgII knockdown could alleviate pathological retinal neovascularization in OIR. Conversely, SgII knockdown have no detectable effect in embryonic physiological vasculature. Experiments in vitro and in vivo further verified SN's angiogenic effect on the eye. In further, we identified that SN promoted angiogenesis via activation of Epidermal Growth Factor Receptor (EGFR), Insulin Receptor (IR), and Insulin-like Growth Factor 1 Receptor (IGF-1R), and followed by the phosphorylation of PI3K-AKT-mTOR signaling. In summarize, our study suggests that SN might be a postnatal angiogenic factor, which was critically involved in retinal pathological neovascularization, but not in embryonic retinal physiological vasculature. Moreover, we identified the receptors and the downstream signaling involved in SN induced retinal angiogenesis.

AIP1 Regulates Ocular Angiogenesis Via NLRP12-ASC-Caspase-8 Inflammasome-Mediated Endothelial Pyroptosis.

Pathological ocular angiogenesis is a significant cause of irreversible vision loss and blindness worldwide. Currently, most studies have focused on the angiogenesis factors in ocular vascular diseases, and very few endogenous anti-angiogenic compounds have been found. Moreover, although inflammation is closely related to the predominant processes involved in angiogenesis, the mechanisms by which inflammation regulates pathological ocular angiogenesis remain obscure. In this study, a vascular endothelial cells (VECs)-specific anti-angiogenic factor is identified, apoptosis signal-regulating kinase 1(ASK1)-interacting protein-1 (AIP1) as a key pathogenic regulator in a typical ocular angiogenesis model, oxygen-induced retinopathy (OIR), using single-cell RNA sequencing. It is demonstrated that AIP1 inhibited pathological angiogenesis by preventing a particular inflammatory death pathway, namely pyroptosis, in retinal VECs. The assembly of a noncanonical inflammasome is further uncovered, the NLRP12-ASC-caspase-8 inflammasome, which is promoted by decreased AIP1 in OIR. This inflammasome elicited gasdermin D (GSDMD)-dependent endothelial pyroptosis, which in turn promoted the release of vascular endothelial growth factor (VEGF) and interleukin (IL)-1β. Suppression of NLRP12-CASP8-GSDMD axis and AIP1 upregulation reduced VEGF signaling, limiting new vessel formation. These findings reveal a previously uncharacterized inflammatory angiogenic process involving VECs pyroptosis-inducing retinal neovascularization, paving the way for promising therapeutic avenues targeting angiogenesis via AIP1 or pyroptosis.

Single-Cell Multiomics Profiling Reveals Heterogeneity of Müller Cells in the Oxygen-Induced Retinopathy Model.

Retinal neovascularization poses heightened risks of vision loss and blindness. Despite its clinical significance, the molecular mechanisms underlying the pathogenesis of retinal neovascularization remain elusive. This study utilized single-cell multiomics profiling in an oxygen-induced retinopathy (OIR) model to comprehensively investigate the intricate molecular landscape of retinal neovascularization. Mice were exposed to hyperoxia to induce the OIR model, and retinas were isolated for nucleus isolation. The cellular landscape of the single-nucleus suspensions was extensively characterized through single-cell multiomics sequencing. Single-cell data were integrated with genome-wide association study (GWAS) data to identify correlations between ocular cell types and diabetic retinopathy. Cell communication analysis among cells was conducted to unravel crucial ligand-receptor signals. Trajectory analysis and dynamic characterization of Müller cells were performed, followed by integration with human retinal data for pathway analysis. The multiomics dataset revealed six major ocular cell classes, with Müller cells/astrocytes showing significant associations with proliferative diabetic retinopathy (PDR). Cell communication analysis highlighted pathways that are associated with vascular proliferation and neurodevelopment, such as Vegfa-Vegfr2, Igf1-Igf1r, Nrxn3-Nlgn1, and Efna5-Epha4. Trajectory analysis identified a subset of Müller cells expressing genes linked to photoreceptor degeneration. Multiomics data integration further unveiled positively regulated genes in OIR Müller cells/astrocytes associated with axon development and neurotransmitter transmission. This study significantly advances our understanding of the intricate cellular and molecular mechanisms underlying retinal neovascularization, emphasizing the pivotal role of Müller cells. The identified pathways provide valuable insights into potential therapeutic targets for PDR, offering promising directions for further research and clinical interventions.

M6A-methylase METTL3 promotes retinal angiogenesis through modulation of metabolic reprogramming in RPE cells

Retinal neovascularization (RNV) disease is one of the leading causes of blindness, yet the molecular underpinnings of this condition are not well understood. To delve into the critical aspects of cell-mediated angiogenesis, we analyzed our previously published single-cell data. Our analysis revealed that retinal pigment epithelium (RPE) cells serve a crucial promotional function in angiogenesis. RPE cells were regulated by N6-methyladenosine (m6A). Next, we detected several critical m6A methylase in hypoxic ARPE-19 cells and in oxygen-induced retinopathy (OIR) mice, our results revealed a significant decrease in the level of methyltransferase like 3 (METTL3). METTL3 specific inhibitor STM2457 intravitreal injection or METTL3 conditional knockout mice both showed a significantly reduced neovascularization area of retina. Additionally, the angiogenesis-related abilities of human retinal endothelial cells (HRECs) were diminished after co-cultured with ARPE-19 treated with STM2457 or sh-METTL3 in vitro. Furthermore, through the integration of Methylated RNA immunoprecipitation (MeRIP) sequencing and RNA sequencing, we discovered that the metabolic enzyme quinolinate phosphoribosyltransferase (QPRT) was directly modified by METTL3 and recognized by the YTH N6-methyladenosine RNA binding protein C1 (YTHDC1). Moreover, after over-expressing QPRT, the angiogenic abilities of HRECs were improved through the phosphorylated phosphatidylinositol-3-kinase (p-PI3K)/ phosphorylated threonine kinase (p-AKT) pathway. Collectively, our study provided a novel therapeutic target for retinal angiogenesis.

Unilateral retinal neovascularization associated with recurrent vitreous hemorrhage in a patient with gyrate atrophy.

To describe the first case of unilateral peripheral retinal neovasularization associated with recurrent vitreous hemorrhage and localised tractional retinal detachment in a patient with gyrate atrophy (GA). Interventional case report. A 23-year-old man with confirmed diagnosis of gyrate atrophy presented with vitreous hemorrhage and history of stable peripheral inferior tractional retinal detachment in the left eye. After three months, the vitreous hemorrhage partially reabsorbed and peripheral retinal vascular abnormalities with focal neovascularization were detected with associated tractional retinal detachment and confirmed on fluorescein angiography. Cryotherapy was performed to prevent any further bleeding. Twelve months later, the left eye remained stable and no further vitreous bleeding occurred. The combination of peripheral retinal neovascularization, localised tractional retinal detachment and recurrent vitreous hemorrhage can be a unilateral complication of gyrate atrophy. In similar cases, cryotherapy may represent a valuable therapeutic option to prevent recurrent bleeding.

Retinal Vascular Changes in a Case of Straatsma Syndrome.

A 34-year-old asymptomatic woman with a history of amblyopia in her right eye presented for a routine examination. Fundus examination revealed broad myelinated nerve fibers along with telangiectatic vessels. Wide-field fluorescein angiography revealed no evidence of ischemia or active retinal neovascularization. However, myelinated nerve fibers can infrequently exhibit cooccurring retinal vascular anomalies, harboring the potential for sight-threatening complications. Patients should be carefully monitored for the development of neovascularization and secondary complications. [Ophthalmic Surg Lasers Imaging Retina 2024;55:XX-XX.].

Characterization of RNA editing and gene therapy with a compact CRISPR-Cas13 in the retina

CRISPR-Cas13 nucleases are programmable RNA-targeting effectors that can silence gene expression in a transient manner. Recent iterations of Cas13 nucleases are compact for adeno-associated virus (AAV) delivery to achieve strong and persistent expression of various organs in a safe manner. Here, we report significant transcriptomic signatures of Cas13bt3 expression in retinal cells and show all-in-one AAV gene therapy with Cas13bt3 can effectively silence VEGFA mRNA in human retinal organoids and humanized VEGF transgenic mouse (trVEGF029, Kimba) models. Specifically, human embryonic stem cells (hESC)-derived retinal pigment epithelium cells show high expression of Cas13bt3 from virus delivery corresponding to a significant reduction of VEGFA mRNA. We further show that intravitreal delivery of Cas13bt3 by AAV2.7m8 can efficiently transduce mouse retinal cells for specific knockdown of human VEGFA in the Kimba mouse. Our results reveal important considerations for assessing Cas13 activity, and establish the Cas13bt3 RNA editing system as a potential anti-VEGF agent that can achieve significant control of VEGFA for the treatment of retinal neovascularization.

Ganglion cell-derived LysoPS induces retinal neovascularisation by activating the microglial GPR34-PI3K-AKT-NINJ1 axis

Retinal neovascularisation is a major cause of blindness in patients with proliferative diabetic retinopathy (PDR). It is mediated by the complex interaction between dysfunctional ganglion cells, microglia, and vascular endothelial cells. Notably, retinal microglia, the intrinsic immune cells of the retina, play a crucial role in the pathogenesis of retinopathy. In this study, we found that lysophosphatidylserines (LysoPS) released from injured ganglion cells induced microglial extracellular trap formation and retinal neovascularisation. Mechanistically, LysoPS activated the GPR34-PI3K-AKT-NINJ1 signalling axis by interacting with the GPR34 receptor on the microglia. This activation upregulated the expression of inflammatory cytokines, such as IL-6, IL-8, VEGFA, and FGF2, and facilitated retinal vascular endothelial cell angiogenesis. As a result, inhibition of the GPR34-PI3K-AKT-NINJ1 axis significantly decreased microglial extracellular trap formation and neovascularisation by suppressing LysoPS-induced microglial inflammatory responses, both in vitro and in vivo. This study reveals the crucial role of apoptotic ganglion cells in activating microglial inflammation in PDR, thereby enhancing our understanding of the pathogenesis of retinal neovascularisation.

Therapeutic effects of Mudan granules on diabetic retinopathy: Mitigating fibrogenesis caused by FBN2 deficiency and inflammation associated with TNF-α elevation

Ethnopharmacological relevanceMudan granules (MuD), a time-honored traditional Chinese patent medicine (TCPM), are widely utilized in the clinical treatment of diabetic peripheral neuropathy (DPN). In the field of biomedical diagnostics, both diabetic retinopathy (DR) and DPN are recognized as critical microvascular complications associated with diabetes. According to the principles of traditional Chinese medicine (TCM), these conditions are primarily attributed to a deficiency in Qi and the obstruction of collaterals. Despite this, the protective effects of MuD on DR and the underlying mechanisms remain to be comprehensively elucidated. Aims of the studyThe purpose of this study was to investigate the effect of MuD on DR and to further explore the promising therapeutic targets. MethodsA diabetic mouse model was established by administering 60 mg/kg of streptozotocin (STZ) via intraperitoneal injection for five consecutive days. The therapeutic efficacy of MuD was evaluated using a comprehensive approach, which included electroretinogram (ERG) analysis, histopathological examination, and assessment of serum biochemical markers. Then, the pharmacodynamic mechanisms of MuD were systematically analyzed using Tandem Mass Tags-based proteomics. Meanwhile, the candidate compounds of MuD were analyzed by ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS) and molecular docking was applied to estimate the affinity of the active ingredient to their potential key targets. In addition, the functional mechanisms identified through bioinformatics analysis were confirmed by molecular biological methods. ResultsWe demonstrated that MuD provided significant protection to retinal function and effectively mitigated the reduction in retinal thickness observed in the animal model. Through proteomic analysis, we identified a substantial regulation by MuD of 70 biomarkers associated with diabetic retinal damage. These proteins were notably enriched in the tumor necrosis factor (TNF) signaling pathway, a critical mediator in inflammatory processes. A particularly intriguing finding was the significant downregulation of fibrillin-2 (FBN2) in the diabetic retina compared to the control group (0.36 times the level), and its most pronounced upregulation (3.26 times) in the MuD treatment group. This suggests that FBN2 may play a pivotal role in the protective effects of MuD. Molecular docking analyses have unveiled a robust interplay between the components of MuD and TNF-α. Further corroboration was provided by molecular biological methods, which confirmed that MuD could suppress TNF-mediated inflammation and prevent retinal neovascularization and fibrogenesis. ConclusionMuD have the potential to alleviate diabetic retinal dysfunction by effectively curbing the fibrogenesis-associated neoangiogenesis and mitigating the inflammatory response, thereby restoring retinal health and function.

Role of SIRT-1 Gene in The Development of Diabetic Retinopathy

Background: Diabetes mellitus (DM) has had a consistent increase in global prevalence. A common microvascular disease associated with diabetes is diabetic retinopathy (DR). As a complex, progressive, as well as asymptomatic neurovascular consequence of DM, DR is the leading cause of vision impairment and blindness in working-age people. The presence of retinal neovascularization classifies diabetic retinopathy (DR) as proliferative, non-proliferative, or diabetic macular edema. Aim of the Study: to evaluate the level of expression of mRNA sirt1- gene in cases of type 2 DM that have retinopathy or vulnerable to it. Patients and Methods: In this research, 60 cases (15 patients with diabetic retinopathy, 15 diabetic cases without retinopathy (PDR), and 30 non-diabetic controls) were recruited. SIRT1 mRNA expression from the two groups was analyzed. Notably, patients with DR exhibited a decrease in the expression of SIRT1 mRNA. ELISA was also used to measure the levels of IL-17 expression in the serum. The results showed that the sera of people with DR had higher levels of IL-17 expression than the sera of healthy people. Results: The findings of this research indicate that imbalanced IL-17 &amp; SIRT1 expression levels may play a role in the etiology of DR, with SIRT1 potentially exerting a protective effect by suppressing IL-17 production.

METTL14-mediated m6A methylation regulates pathological retinal neovascularization by targeting autophagy

Pathological retinal neovascularization (RNV) is a prevalent characteristic of various ocular diseases, including proliferative diabetic retinopathy (PDR), retinopathy of prematurity (ROP), and retinal vein occlusion (RVO). While the importance of N6-methyladenosine (m6A) modification in diverse disease contexts is well-established, its functional role in pathological RNV remains unclear. Herein, we investigated the involvement of m6A modification and its core methyltransferase, METTL14, in a model of oxygen-induced retinopathy (OIR) to elucidate their contribution to retinal angiogenesis. In this study, we observed heightened levels of m6A modification and elevated expression of METTL14 in the OIR model, suggesting their potential implication in pathological RNV. Employing targeted knockdown of METTL14, we revealed that its depletion activated autophagy flux in human retinal vascular endothelial cells (HRVECs), consequently inhibiting the angiogenic capacity of endothelial cells. Mechanistically, we demonstrated that METTL14 exerts its regulatory influence on autophagy flux by modulating the stability of ATG7, a pivotal protein involved in autophagy. Specifically, METTL14 knockdown led to increased ATG7 expression at both mRNA and protein levels, accompanied by reduced m6A methylation of ATG7 mRNA and enhanced mRNA stability. Moreover, silencing of ATG7 counteracted the effects of METTL14 knockdown on endothelial cell functions, emphasizing ATG7 as a downstream target of METTL14-mediated autophagy in HRVECs. After all, our findings provide valuable insights into the pathogenesis of retinal pathological angiogenesis and potential therapeutic targets for the treatment of ocular neovascular diseases.

Phlebotomy-induced anemia reduces oxygen-induced retinopathy severity and dampens retinal developmental transcriptomic pathways in rats.

Phlebotomy-induced-anemia (PIA), which induces tissue hypoxia and angiogenesis, occurs universally among infants at risk for severe retinopathy of prematurity (ROP). We hypothesized that PIA exacerbates pathologic retinal neovascularization in ROP. We induced PIA to a hematocrit of 18% among rats undergoing the established 50/10 oxygen-induced retinopathy (OIR) model. Rats were euthanized at P15 and P20, during the avascular and neovascular phases of OIR, respectively. Retinal vascular morphometry, cytokine/chemokine concentrations, transcriptomes, and mRNA expression of angiogenic and iron-deficiency markers were compared to non-PIA controls. In OIR, PIA decreased percent avascular area at P15 by 35%, percent neovascular area at P20 by 42%, and select pro-inflammatory cytokine/chemokine concentrations at both time points. At P20, PIA increased mRNA expression of angiopoietin 2/ vascular endothelial growth factor-A 2-fold and transferrin and transferrin receptor 5-fold. RNA sequencing showed dampened pathways of angiogenesis, inflammation, and neural development in anemic OIR females. Contrary to our hypothesis, PIA decreased OIR severity and retinal cytokine and chemokine levels and dampened transcriptomic pathways central to retinal vascular and neural development in neonatal rats. These data suggest PIA provides a protective effect from OIR. Further investigation into the functional effect of these molecular changes is warranted. This is the first preclinical study to investigate the impact of neonatal anemia on oxygen-induced retinopathy (OIR) outcomes. This study adds to the literature that anemia decreases neovascularization, decreases cytokine and chemokine levels, and dampens angiogenic and neural transcriptomic pathways in the rat 50/10 OIR model. The study identifies a sex-specific transcriptomic response to anemia in the 50/10 OIR model, with females primarily impacted.

Reassessment of arterial versus venous perfusion of diabetic retinal neovascularization using ultrawide-field fluorescein angiography.

The purpose of this study was to assess whether diabetic NV is perfused by the arterial or the venous circulation. This is a retrospective, consecutive case series evaluating patients with proliferative diabetic retinopathy (PDR) imaged with ultrawide-field (UWF) fluorescein angiography (FA). Areas of neovascularization elsewhere (NVE) and neovascularization of the disc (NVD) were assessed. Perfusion was defined as arterial, arteriovenous, or venous if the area of diabetic neovascularization (NV) began to hyperfluoresce either prior, during, or after laminar venous flow, respectively. A total of 180 eyes from 176 patients with 928 NV were identified (830 NVE, 98 NVD). Of those, 5.1% of NVE were classified as arterial and 58.2% of NVD were classified as arterial. The remaining NV were classified as arteriovenous except for a small subset (6.1%) which were indeterminate. None of the NV were classified as venous. Noteworthy examples demonstrated NV that nearly fully perfused prior to any detectable fluorescence within nearby veins as well as clear shunting of blood from a feeding artery to a draining vein. UWF FA images suggest that some NV is perfused by retinal arteries. This may be useful in devising strategies for early detection and treatment of NV precursors. What is known • Diabetic retinal neovascularization has long been thought to be perfused by the retinal venous circulation. • Vascular endothelial growth factor has been shown to play key roles in both angiogenesis and arteriogenesis. What is new • Ultrawide-field fluorescein angiography demonstrates that at least some diabetic neovascularization is perfused by the retinal arterial circulation. • This supports the hypothesis that diabetic neovascularization may arise from arterially-perfused intraretinal microvascular abnormalities in the capillary bed.

Bruton's tyrosine kinase inhibition suppresses pathological retinal angiogenesis.

Pathological retinal angiogenesis is a typical manifestation of vision-threatening ocular diseases. Many patients exhibit poor response or resistance to anti-vascular endothelial growth factor (VEGF) agents. Bruton's tyrosine kinase (BTK) controls the proliferation and function of immune cells. Therefore, we examined the anti-inflammatory and anti-angiogenic effects of BTK inhibition on retinal angiogenesis. Retinal neovascularisation and vascular leakage in oxygen-induced retinopathy in C57/BL6J mice were assessed by whole-mount retinal immunofluorescence. PLX5622 was used to deplete microglia and Rag1-knockout mice were used to test the contribution of lymphocytes to the effects of BTK inhibition. The cytokines, activation markers, inflammatory and immune-regulatory activities of retinal microglia/macrophages were detected using qRT-PCR and immunofluorescence. NLRP3 was detected by western blotting, and the effects of BTK inhibition on the co-culture of microglia and human retinal microvascular endothelial cells (HRMECs) were examined. BTK inhibition suppressed pathological angiogenesis and vascular leakage, and significantly reduced retinal inflammation, which involved microglia/macrophages but not lymphocytes. BTK inhibition increased anti-inflammatory factors and reduced pro-inflammatory cytokines that resulted from NLRP3 inflammasome activation. BTK inhibition suppressed the inflammatory activity of microglia/macrophages, and acted synergistically with anti-VEGF without retinal toxicity. Moreover, the supernatant of microglia incubated with BTK-inhibitor reduced the proliferation, tube formation and sprouting of HRMECs. BTK inhibition suppressed retinal neovascularisation and vascular leakage by modulating the inflammatory activity of microglia and macrophages. Our study suggests BTK inhibition as a novel and promising approach for alleviating pathological retinal angiogenesis.

Branch retinal vein occlusion and peripheral nonperfusion associated with astrocytic hamartoma of the optic nerve head in a patient with tuberous sclerosis.

To report a case of branch retinal vein occlusion (BRVO) causing retinal neovascularization (NV) and vitreous hemorrhage associated with astrocytic hamartoma (AH) involving the optic nerve head in a patient with tuberous sclerosis complex (TSC). We review the natural history of the clinical presentation and posit its etiology. Electronic health records were reviewed for patient history and demographics and multimodal ophthalmic imaging including fundus photography, fluorescein angiography, and optical coherence tomography (OCT). Neovascularization emanating superiorly and inferiorly from a large AH of the optic nerve head was identified as the cause of a longstanding vitreous hemorrhage. Retinal nonperfusion was also found in superior peripheral quadrants, most notably distal to the superior NV. OCT was useful in visualizing small retinal AH in the fellow eye that was otherwise undetected on prior dilated fundus examinations. The patient was treated with intravitreal anti-VEGF and superior sectoral PRP in the involved eye. BRVO and associated NV may represent rare vision-threatening sequela of AH in TSC and manifested in this case with diffuse peripheral retinal nonperfusion secondary to BRVO-induced ischemia. OCT is a valuable resource in identifying and monitoring AH of the retina.

Heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation.

Diabetic retinopathy is characterised by neuroinflammation that drives neuronal and vascular degenerative pathology, which in many individuals can lead to retinal ischaemia and neovascularisation. Infiltrating macrophages and activated retina-resident microglia have been implicated in the progression of diabetic retinopathy, although the distinct roles of these immune cells remain ill-defined. Our aim was to clarify the distinct roles of macrophages/microglia in the pathogenesis of proliferative ischaemic retinopathies. Murine oxygen-induced retinopathy is commonly used as a model of ischaemia-induced proliferative diabetic retinopathy (PDR). We evaluated the phenotype macrophages/microglia by immunostaining, quantitative real-time RT-PCR (qRT-PCR), flow cytometry and scRNA-seq analysis. In clinical imaging studies of diabetic retinopathy, we used optical coherence tomography (OCT) and OCT angiography. Immunostaining, qRT-PCR and flow cytometry showed expression levels of M1-like macrophages/microglia markers (CD80, CD68 and nitric oxide synthase 2) and M2-like macrophages/microglia markers (CD206, CD163 and macrophage scavenger receptor 1) were upregulated in areas of retinal ischaemia and around neo-vessels, respectively. scRNA-seq analysis of the ischaemic retina revealed distinct ischaemia-related clusters of macrophages/microglia that express M1 markers as well as C-C chemokine receptor 2. Inhibition of Rho-kinase (ROCK) suppressed CCL2 expression and reduced CCR2-positive M1-like macrophages/microglia in areas of ischaemia. Furthermore, the area of retinal ischaemia was reduced by suppressing blood macrophage infiltration not only by ROCK inhibitor and monocyte chemoattractant protein-1 antibody but also by GdCl3. Clinical imaging studies of diabetic retinopathy using OCT indicated potential involvement of macrophages/microglia represented by hyperreflective foci in areas of reduced perfusion. These results collectively indicated that heterotypic macrophages/microglia differentially contribute to retinal ischaemia and neovascularisation in retinal vascular diseases including diabetic retinopathy. This adds important new information that could provide a basis for a more targeted, cell-specific therapeutic approach to prevent progression to sight-threatening PDR.

Dense perivenular clustering of microaneurysms: A pointer of leukemic retinopathy?

A boy in his late teens with a history of low-grade fever evaluated for a hematological malignancy was screened for ocular involvement. The fundus examination revealed a hyperemic disc with engorged tortuous retinal veins, pseudo sheathing of the peripheral retinal vasculature with surrounding retinal hemorrhages, and retinal infiltrates suggestive of leukemic retinopathy. Wide-field fundus fluorescein angiography showed areas of capillary non-perfusion along with characteristic dense segregation of multiple perivenular microaneurysms with sparing of the arterioles. The patient was diagnosed with chronic myeloid leukemia and treated with imatinib mesylate. No active ophthalmic treatment was carried out because there was no evidence of treatable retinal complications such as macular edema or retinal neovascularization. Clearance of leukemic infiltrates, along with complete regression of the microaneurysms, were observed 6 weeks after the treatment.

TRNA-derived fragment tRF-30 propels diabetes-induced retinal microvascular complications by regulating STAT3 signaling.

Transfer RNA-derived fragments (tRFs) represent a novel class of non-coding RNA transcripts that possess specific biological functions. However, the involvement of tRFs in retinal microvascular diseases remains poorly understood. In this study, we aimed to reveal whether modulation of tRF-30 expression could attenuate pathological retinal neovascular diseases. Our findings demonstrate a significant upregulation of tRF-30 expression levels in both in vivo models of diabetic retinopathy (DR) and in vitro endothelial sprouting models. Conversely, inhibition of tRF-30 expression suppressed the formation of abnormal neovascularization in the retina in vivo, while reducing the proliferation and migration activity of retinal vascular endothelial cells in vitro. We also found that tRF-30 modulates retinal neovascularization through the tRF-30/TRIB3/signal transducer and activated transcription 3 signaling pathway. Furthermore, we validated a significant upregulation of tRF-30 expression levels in the vitreous humor of DR patients, with high levels of both validity and specificity in diagnostic testing. Collectively, our findings highlight a pro-angiogenic role for tRF-30 in DR. Intervening in the tRF-30 signaling pathway may represent a promising prevention and treatment strategy for retinal angiogenesis.