Diabetic retinopathy (DR) is one of the main causes of vision loss and irreversible blindness in the working-age population, closely regarded as the destruction of the retinal neurovascular unit (NVU). As an important component of the NVU, retinal microglia (RMG) plays a vital role in the progression of DR. In recent years, single-cell RNA sequencing (scRNA-seq) technology has emerged as an important tool in transcriptomic analysis. This latest method reveals the heterogeneity and complexity of RNA transcriptional profiles within individual cells, as well as the composition of different cell types and functions. Utilizing scRNA-seq technology, researchers have further revealed the role of RMG in the occurrence and development of DR, discovering phenotypic heterogeneity, regional heterogeneity, and cell-to-cell communication in RMG. It is anticipated that in the future, more omics technologies and multi-omics correlation analysis methods will be applied to DR and even other ophthalmic diseases, exploring potential diagnostic and therapeutic targets, providing different perspectives for the clinical diagnosis, treatment, and scientific research of DR, and truly promoting clinical translation through technological innovation, thereby benefiting patients with DR diseases.
Objective To investigate if insulin can affect the expression of vascular endothelial growth factor (VEGF) in the retina of streptozotocin-induced diabetic rats. Methods A total of 60 male SpragueDawley rats were randomly divided into sodium citrate buffer control group (CIT-CON, n=30) and STZ-induced diabetic group (STZ-DM, n=30). At the 16th week, 24 rats from CIT-CON group at random were randomly divided to group A (sodium citrate buffer control group, n=12) and group B (sodium citrate buffer plus insulin group, n=12). The remaining 6 rats from as CIT-CON group served as negative control. At the same time, 24 rats from STZDM group at random were randomly divided to group C (STZinduced diabetic group, n=12) and group D (STZ-induced diabetic plus insulin group, n=12). The remaining 6 rats from STZ-DM group also served as negative control. 4 IU of insulin was injected subcutaneously to rats of group B and D. Immunohistochemistry, Western blot and Real-time polymerase chain reaction (RT-PCR) were used to measure the expression level of VEGF protein and mRNA respectively. RESULTS Insulin significantly increased the VEGF mRNA (7.71plusmn;0.25 vs 5.36plusmn;0.37, t test Plt;0.05) and protein expression (0.4925plusmn;0.0122 vs 0.4272plusmn;0.0110, t test Plt;0.05) in the retina of CITCON rats. However, in retina of STZDM rats, insulin had no effect on VEGF mRNA (8.92plusmn;0.27 vs 9.05plusmn;0.28, t test, Pgt;0.05) and protein expression (0.5152plusmn;0.0109 vs 0.5099plusmn;0.0100, t test Pgt;0.05). Conclusions Insulin had no effect on VEGF expression in the retina of STZ-DM rats.
ObjectiveTo observe the alterations of vascular density of superficial or deep retinal vascular plexus and the area of foveal avascular zone (FAZ) in acute central serous chorioretinopathy (CSC) eyes.MethodsThis is a retrospective study including 22 patients with unilateral CSC in acute stages. The patients were divided into group A (22 affected eyes) and B (22 fellow eyes). Twenty eyes of 20 age and gender-matched healthy volunteers (group C) were enrolled in this study. All subjects underwent optical coherence tomography (OCT) angiography examinations. The observation index included signal intensity of blood flow in choroidal capillary, vessel density and FAZ on the superficial capillary plexus (SCP) and deep capillary plexus (DCP).ResultsThe FAZ on DCP in group A was larger than that in group B and C (t=4.28, 5.57; P=0.00、0.00), but there was no significant difference of FAZ on SCP among 3 groups (t=0.28, 0.80; P=0.78, 0.43). The vessel density of SCP and DCP in group A and B were decreased than those in group C (t=−4.40, −2.91; P=0.00, 0.00). The type of choroidal capillaries dilation had two different manifestations by OCTA, which was circumscribed in 12 eyes and diffuse in 10 eyes. The subretinal fluid in macular area which presented dark chamber with weak reflection was observed by en-face OCT.ConclusionsThe vessel density of SCP and DCP in both eyes of acute CSC are lower than those in normal eyes. The FAZ of DCP in affected eyes of acute CSC is larger than that in fellow eyes and normal eyes. The blood flow of dilated choroidal capillary can be manifested as different morphological enhancements.
Objective To investigate if lactic acid can promote the expression of vascular endothelial growth factor (VEGF) in the rat retinal explants.Methods The retinas of two-week neonatal SD rats were placed onto the culture plate inserts and incubated with Dulbeccoprime;s modified Eagleprime;s medium （DMEM） plus 2% fetal bovine serum (FBS) containing 10,20,30 mmol/L of lactic acid, respectively. Each group had 24 retinas. At 24 hours after incubation, the retinas were sectioned for light microscopy and the expression of VEGF was measured by real time PCR and Western blot. Results The cultured retinas maintained intact construction, and no cytolysis and apoptosis were observed under light microscope. RT-PCR showed the levels of VEGF mRNA were 0.74plusmn;0.06 for 10 mmol/L lactic acid group, 0.99plusmn;0.12 for 20 mmol/L group, and 1.45plusmn;0.17 for 30 mmol/L group respectively. VEGF expression was 0.34plusmn;0.15 for 10 mmol/L, 0.54plusmn;0.16 for 20 mmol/L, and 0.93plusmn;0.23 for 30 mmol/L group respectively by Western blot. Both PCR and Western blot showed 30 mmol/L of lactic acid significantly increased the levels of VEGF mRNA and VEGF expression. Conclusion The induction of retinal VEGF by lactic acid is concentration-dependent.
ObjectiveTo observe the clinical and multimodal imaging features of eyes with acute macular neuroretinopathy (AMN) associated with the coronavirus disease 2019 (COVID-19). MethodsA retrospective study. From December 20, 2022 to January 17, 2023, a total of 29 patients (58 eyes) with COVID-19-associated AMN admitted to Department of Ophthalmology of Eye and ENT Hospital, Shanghai Medical College were included in the study. All the affected eyes underwent the best corrected visual acuity, color fundus photography, infrared fundus photography (IR), short-wavelength autofluorescence (SW-AF), near-infrared autofluorescence (NIL-AF), optical coherence tomography (OCT), and OCT angiography (OCTA). All patients were administered microcirculation-improving oral medication with 12 cases receiving adjunctive low-dose corticosteroid therapy. Follow-ups were conducted 1 to 3 months after the initial diagnosis, with a total of 19 cases (38 eyes) completing the one-month follow-up. ResultsOut of the 29 cases, there were 9 males (18 eyes) and 20 females (40 eyes), all of whom experienced bilateral eye involvement. The age of the patients ranged from 12 to 47 years, with an average age of (29.9±9.5) years. The time from the onset of fever to the appearance of ocular symptoms was (2.52±2.01) days. Among the 58 affected eyes, there were 5 cases with retinal cotton wool spots, 2 cases with optic disc edema, and 1 case with parafoveal branch retinal vein occlusion. All affected eyes exhibited deep reddish-brown macular dark spots. IR revealed wedge-shaped, wedge-like, or "petaloid-like" dark areas involving the fovea and parafovea. SW-AF examination showed no obvious abnormality in 39 eyes. Weak autofluorescence dark area were consistent with IR in 19 eyes. NIR-AF examination showed spot-like or flaky self-fluorescent dark areas. OCT examination showed strong reflex lesions spreading vertically upward from the retinal pigment epithelium (RPE) layer in the macular area in the acute stage, showing typical "bean seedling" sign. OCTA revealed reduced blood flow density in the deep capillary plexus (DCP) of 50 eyes. En-face OCT displayed lesion areas that corresponded to the dark areas seen in IR. One month after the initial diagnosis, the condition improved in 18 eyes (47.4%, 18/38). Among the 5 eyes with cotton wool spots, regression of these spots was accompanied by loss of nerve fiber layer in 4 eyes. In cases with optic disc edema, the edema subsided. The "bean sprout" sign disappeared in all affected eyes, and the lesions became localized. The ellipsoid zone and/or interdigitation zone in the lesion areas were discontinuous. ConclusionsCOVID-19-related AMN is characterized by distinctive features. IR fundus reveals wedge-shaped, wedge-like, or petaloid dark areas involving the fovea and parafovea. OCT displays strongly reflective lesions with vertical spread above the RPE. OCTA shows reduced blood flow density in the DCP of the retina.