Sodium butyrate ameliorates diabetic retinopathy in mice via the regulation of gut microbiota and related short-chain fatty acids.

BACKGROUND: Diabetic retinopathy (DR) development is associated with disturbances in the gut microbiota and related metabolites. Butyric acid is one of the short-chain fatty acids (SCFAs), which has been found to possess a potential antidiabetic effect. However, whether butyrate has a role in DR remains elusive. This study aimed to investigate the effect and mechanism of sodium butyrate supplementation on DR. METHODS: C57BL/6J mice were divided into three groups: Control group, diabetic group, and diabetic with butyrate supplementation group. Type 1 diabetic mouse model was induced by streptozotocin. Sodium butyrate was administered by gavage to the experimental group daily for 12 weeks. Optic coherence tomography, hematoxylin-eosin, and immunostaining of whole-mount retina were used to value the changes in retinal structure. Electroretinography was performed to assess the retinal visual function. The tight junction proteins in intestinal tissue were evaluated using immunohistochemistry. 16S rRNA sequencing and LC-MS/MS were performed to determine the alteration and correlation of the gut microbiota and systemic SCFAs. RESULTS: Butyrate decreased blood glucose, food, and water consumption. Meanwhile, it alleviated retinal thinning and activated microglial cells but improved electroretinography visual function. Additionally, butyrate effectively enhanced the expression of ZO-1 and Occludin proteins in the small intestine. Crucially, only butyric acid, 4-methylvaleric acid, and caproic acid were significantly decreased in the plasma of diabetic mice and improved after butyrate supplementation. The deeper correlation analysis revealed nine genera strongly positively or negatively correlated with the above three SCFAs. Of note, all three positively correlated genera, including norank_f_Muribaculaceae, Ileibacterium, and Dubosiella, were significantly decreased in the diabetic mice with or without butyrate treatment. Interestingly, among the six negatively correlated genera, Escherichia-Shigella and Enterococcus were increased, while Lactobacillus, Bifidobacterium, Lachnospiraceae_NK4A136_group, and unclassified_f_Lachnospiraceae were decreased after butyrate supplementation. CONCLUSION: Together, these findings demonstrate the microbiota regulating and diabetic therapeutic effects of butyrate, which can be used as a potential food supplement alternative to DR medicine.

Chinese Guideline on the Management of Polypoidal Choroidal Vasculopathy (2022).

Background In mainland China, patients with neovascular age-related macular degeneration (nAMD) have approximately an 40% prevalence of polypoidal choroidal vasculopathy (PCV). This disease leads to recurrent retinal pigment epithelium detachment (PED), extensive subretinal or vitreous hemorrhages, and severe vision loss. China has introduced various treatment modalities in the past years and gained comprehensive experience in treating PCV.Methods A total of 14 retinal specialists nationwide with expertise in PCV were empaneled to prioritize six questions and address their corresponding outcomes, regarding opinions on inactive PCV, choices of anti-vascular endothelial growth factor (anti-VEGF) monotherapy, photodynamic therapy (PDT) monotherapy or combined therapy, patients with persistent subretinal fluid (SRF) or intraretinal fluid (IRF) after loading dose anti-VEGF, and patients with massive subretinal hemorrhage. An evidence synthesis team conducted systematic reviews, which informed the recommendations that address these questions. This guideline used the GRADE (Grading of Recommendations, Assessment, Development, and Evaluation) approach to assess the certainty of evidence and grade the strengths of recommendations. Results The panel proposed the following six conditional recommendations regarding treatment choices. (1) For patients with inactive PCV, we suggest observation over treatment. (2) For treatment-na?ve PCV patients, we suggest either anti-VEGF monotherapy or combined anti-VEGF and PDT rather than PDT monotherapy. (3) For patients with PCV who plan to initiate combined anti-VEGF and PDT treatment, we suggest later/rescue PDT over initiate PDT. (4) For PCV patients who plan to initiate anti-VEGF monotherapy, we suggest the treat and extend (T&E) regimen rather than the pro re nata (PRN) regimen following three monthly loading doses. (5) For patients with persistent SRF or IRF on optical coherence tomography (OCT) after three monthly anti-VEGF treatments, we suggest proceeding with anti-VEGF treatment rather than observation. (6) For PCV patients with massive subretinal hemorrhage (equal to or more than four optic disc areas) involving the central macula, we suggest surgery (vitrectomy in combination with tissue-plasminogen activator (tPA) intraocular injection and gas tamponade) rather than anti-VEGF monotherapy. Conclusions Six evidence-based recommendations support optimal care for PCV patients' management.

COL10A1 is a novel factor in the development of choroidal neovascularization.

With the dramatic rise in the aging population, researching age-related macular degeneration (AMD), especially the severe form neovascular AMD (nAMD), has become more important than ever. In this study, we found that collagen type X was increased in retina-choroid tissue of mice with laser-induced choroidal neovascularization (CNV) based on immunohistofluorescence. RNA sequencing and bioinformatic analyses were performed to compare the retina-choroid tissue complex of the CNV mouse model to normal controls. Collagen type X alpha 1 chain (Col10a1) was among the most significantly upregulated genes, and the results were validated with an animal model at the mRNA and protein levels by quantitative real-time polymerase chain reaction (qPCR) and western blotting, respectively. COL10A1 was also upregulated in human retinal microvascular endothelial cells (HRMECs), human umbilical vein endothelial cells (HUVECs), RPE19 cells and RF/6A cells under hypoxic conditions. Next, in vitro and in vivo experiments were performed to study the effect of COL10A1 on neovascularization. siRNA knockdown of COL10A1 suppressed the proliferation and tube formation ability of HRMECs under hypoxic conditions. Snail family transcriptional repressor 1 (SNAIL1) and angiopoietin-2 (ANGPT2) were downregulated in COL10A1 knockdown HRMECs under hypoxic conditions and thus were potential downstream genes. Significant decreases in CNV leakage and CNV lesion area, as assessed by fundus fluorescein angiography (FFA) and immunofluorescence of choroidal flat mounts, respectively, were observed in a mouse model intravitreally injected with anti-collagen X monoclonal antibody (mAb) compared to the controls. In conclusion, COL10A1 promotes CNV formation and may represent a new candidate target for the treatment and diagnosis of nAMD and other neovascular diseases.

Suppression of EZH2 inhibits TGF-ß1-induced EMT in human retinal pigment epithelial cells.

Epithelial-mesenchymal transition (EMT) of retinal pigment epithelium (RPE) cells is critically involved in the occurrence of subretinal fibrosis. This study aimed to investigate the role of enhancer of zeste homolog 2 (EZH2) in EMT of human primary RPE cells and the underlying mechanisms of the anti-fibrotic effect of EZH2 suppression. Primary cultures of human RPE cells were treated with TGF-ß1 for EMT induction. EZH2 was silenced by siRNA to assess the expression levels of epithelial and fibrotic markers using qRT-PCR, Western blot, and immunofluorescence staining assay. Furthermore, the cellular migration, proliferation and barrier function of RPE cells were evaluated. RNA-sequencing analyses were performed to investigate the underlying mechanisms of EZH2 inhibition. Herein, EZH2 silencing up-regulated epithelial marker ZO-1 and downregulated fibrotic ones including α-SMA, fibronectin, and collagen 1, alleviating EMT induced by TGF-ß1 in RPE cells. Moreover, silencing EZH2 inhibited cellular migration and proliferation, but didn't affect cell apoptosis. Additionally, EZH2 suppression contributed to improved barrier functions after TGF-ß1 stimulation. The results from RNA sequencing suggested that the anti-fibrotic effect of EZH2 inhibition was associated with the MAPK signaling pathway, cytokine-cytokine receptor interaction, and the TGF-beta signaling pathway. Our findings provide evidence that the suppression of EZH2 might reverse EMT and maintain the functions of RPE cells. EZH2 could be a potential therapeutic avenue for subretinal fibrosis.

Tissue-Specific Gamma-Flicker Light Noninvasively Ameliorates Retinal Aging.

Aging is a risk factor for multiple retinal degeneration diseases. Entraining brain gamma oscillations with gamma-flicker light (γFL) has been confirmed to coordinate pathological changes in several Alzheimer's disease mouse models and aged mice. However, the direct effect of γFL on retinal aging remains unknown. We assessed retinal senescence-associated beta-galactosidase (ß-gal) and autofluorescence in 20-month-old mice and found reduced ß-gal-positive cells in the inner retina and diminished lipofuscin accumulation around retinal vessels after 6 days of γFL. In immunofluorescence, γFL was further demonstrated to ameliorate aging-related retinal changes, including a decline in microtubule-associated protein 1 light chain 3 beta expression, an increase in complement C3 activity, and an imbalance between the anti-oxidant factor catalase and pro-oxidant factor carboxymethyl lysine. Moreover, we found that γFL can increase the expression of activating transcription factor 4 (ATF4) in the inner retina, while revealing a decrease of ATF4 expression in the inner retina and positive expression in the outer segment of photoreceptor and RPE layer for aged mice. Western blotting was then used to confirm the immunofluorescence results. After mRNA sequencing (NCBI Sequence Read Archive database: PRJNA748184), we found several main mechanistic clues, including mitochondrial function and chaperone-mediated protein folding. Furthermore, we extended γFL to aged Apoe-/- mice and showed that 1-m γFL treatment even improved the structures of retinal-pigment-epithelium basal infolding and Bruch's membrane. Overall, γFL can orchestrate various pathological characteristics of retinal aging in mice and might be a noninvasive, convenient, and tissue-specific therapeutic strategy for retinal aging.

Transcriptome-wide analysis reveals core sets of transcriptional regulators of sensome and inflammation genes in retinal microglia.

BACKGROUND: Retinal microglial cells (RMCs) play crucial roles in maintaining normal visual functions in a healthy eye. However, the underlying mechanisms of RMCs over-activation manifesting the alterations of sensome profile and inflammation state, which contribute to various retinal neurodegenerative diseases, remain elusive. Here, we aimed to identify the core set of sensome and pro-inflammatory genes and their regulators using transcriptome and data mining approaches. METHODS: We performed paired-end RNA-sequencing in primary microglial cell cultures treated with TNFα/IFNϒ (10 ng/ml for 12 h) and PBS as a control. Gene enrichment analysis and hierarchical clustering for the differentially expressed transcripts highlight functional pathways and network perturbations. We examined overlaps of the mouse microglial gene expression profiles with the data-mined human sensome and pro-inflammatory marker genes. The core sets of sensome and pro-inflammatory genes were selected and predicted for transcription factors (TFs). The identified TFs in RNA-Seq are validated by the quantitative PCR method. RESULTS: TNFα/IFNϒ induced 668 differentially expressed transcripts in retinal microglial cells relative to the control. Furthermore, gene enrichment analysis and the gene expression network revealed activated microglial genes, biological, molecular and inflammatory pathways. The overlapping analysis of the TNFα/IFNϒ-activated microglia genes and the data-mined human gene sets revealed 22 sensome and 61 pro-inflammatory genes. Based on network analysis, we determined 10 genes as the core sets of sensome and pro-inflammatory genes and predicted the top ten TFs that regulate them. The SP110, IRF1, FLI1, SP140 (sensome) and RELB, BATF2, NFKB2, TRAFD1, SP100, NFKB1 (inflammation) are differentially expressed between the TNFα/IFNϒ activated and the non-activated microglia which were validated by quantitative PCR. The outcomes indicate that these transcriptional regulators are highly expressed and may regulate the sensome and inflammatory genes of RMCs and switch them to over-activation. CONCLUSION: Our results comprise a powerful, cross-species functional genomics resource for sensome and inflammation of RMCs, which may provide novel therapeutic approaches to prevent retinal neurodegenerative diseases.

Aberrant Retinal Pigment Epithelial Cells Derived from Induced Pluripotent Stem Cells of a Retinitis Pigmentosa Patient with the PRPF6 Mutation.

Pre-mRNA processing factors (PRPFs) are vital components of the spliceosome and are involved in the physiological process necessary for pre-mRNA splicing to mature mRNA. As an important member, PRPF6 mutation resulting in autosomal dominant retinitis pigmentosa (adRP) is not common. Recently, we reported the establishment of an induced pluripotent stem cells (iPSCs; CSUASOi004-A) model by reprogramming the peripheral blood mononuclear cells of a PRPF6-related adRP patient, which could recapitulate a consistent disease-specific genotype. In this study, a disease model of retinal pigment epithelial (RPE) cells was generated from the iPSCs of this patient to further investigate the underlying molecular and pathological mechanisms. The results showed the irregular morphology, disorganized apical microvilli and reduced expressions of RPE-specific genes in the patient's iPSC-derived RPE cells. In addition, RPE cells carrying the PRPF6 mutation displayed a decrease in the phagocytosis of fluorescein isothiocyanate-labeled photoreceptor outer segments and exhibited impaired cell polarity and barrier function. This study will benefit the understanding of PRPF6-related RPE cells and future cell therapy.

Effect of porcine corneal stromal extract on keratocytes from SMILE-derived lenticules.

Propagating large amounts of human corneal stromal cells (hCSCs) in vitro while maintaining the physiological quality of their phenotypes is necessary for their application in cell therapy. Here, a novel medium to propagate hCSCs obtained from small incision lenticule extraction (SMILE)-derived lenticules was investigated and the feasibility of intrastromal injection of these hCSCs was assessed. Primary hCSCs were cultured in porcine corneal stroma extract (pCSE) with RIFA medium including ROCK inhibitor Y27632, insulin-transferrin-selenium, fibroblast growth factor 2, L-ascorbate 2-phosphate and 0.5% FBS (RIFA medium + pCSE). Protein profiling of the pCSE was identified using nanoscale liquid chromatography coupled to tandem mass spectrometry (nano LC-MS/MS). After subculturing in RIFA medium + pCSE or 10% FBS normal medium (NM), hCSCs at P4 were transplanted into mouse corneal stroma. Compared with NM, ALDH3A1, keratocan and lumican were significantly more expressed in the RIFA medium + pCSE. ALDH3A1 was also more expressed in the RIFA medium + pCSE than in the RIFA medium. Fibronectin and α-SMA were less expressed in the RIFA medium + pCSE than in the NM. Using Metascape analysis, the pCSE with its anti-fibrosis, pro-proliferation and anti-apoptosis activities, was beneficial for hCSC cultivation. The intrastromally implanted hCSCs in the RIFA medium + pCSE had positive CD34 expression but negative CD45 expression 35 days after injection. We provide a valuable new medium that is advantageous for the proliferation of hCSCs with the properties of physiological keratocytes. Intrastromal injection of hCSCs in RIFA medium + pCSE has the potential for clinical cell therapy.

Inhibition of enhancer of zeste homolog 2 prevents corneal myofibroblast transformation in vitro.

PURPOSE: Corneal fibroblast can be transformed into corneal myofibroblasts by TGF-ß1. Enhancer of zeste homolog 2 (EZH2) upregulation has been observed in the occurrence of other fibrotic disorders. We investigated the role of EZH2 in the progression of corneal fibrosis and the antifibrotic effect of EZH2 inhibition in corneal fibroblasts (CFs). METHODS: Primary CFs were isolated from corneal limbi and the CFs were treated with TGF-ß1 to induce fibrosis. EPZ-6438 and EZH2 siRNA were used to inhibit EZH2 expression. Myofibroblast activation and extracellular matrix (ECM) protein synthesis was detected by quantitative real-time PCR, western blotting, and immunofluorescence staining assay. The functions of myofibroblast were evaluated by cell migration and collagen gel contraction assays. Molecular mechanisms involved in EZH2 inhibition were investigated by RNA sequencing. RESULTS: TGF-ß1 activated EZH2 expression in CFs. Treatment with EPZ-6438 (5 µM) and EZH2 siRNA considerably suppressed corneal myofibroblast activation and ECM protein synthesis in CFs induced by TGF-ß1 when compared to the control group. EPZ-6438 (5 µM) suppressed cell migration and gel contraction in CFs. RNA sequencing results revealed that antifibrotic genes were activated after EZH2 inhibition to suppress corneal myofibroblast activation. CONCLUSION: Inhibition of EZH2 suppresses corneal myofibroblast activation and ECM protein synthesis, and could serve as a novel therapeutic target for preventing corneal scarring.

The daily gene transcription cycle in mouse retina.

Many physiological retinal processes, such as outer segment disk shedding and visual sensitivity, exhibit a daily rhythm. However, the detailed transcriptome dynamics and related biological processes of the retina are not fully understood. Retinal tissues were collected from C57BL/6J male mice housed in a 12h light/12h dark (LD) cycle for 4 weeks, at Zeitgeber time (ZT) 0, 4, 8, 12, 16, and 20. Total RNA was extracted from the tissues and used for unique identifier RNA sequencing experiments. The rhythmicity of gene expression was determined using the MetaCycle R package. We found that 1741 genes (10.26%) were rhythmically expressed in the retina. According to the expression patterns, the rhythmically expressed genes were assigned to four clusters, each with about 361-492 genes, using the Mfuzz R package. The Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) analyses were conducted to identify pathways and biological processes of the profiled genes. Genes in Clusters 1 and 4 were associated with glycolysis and energy production, showed higher activity at night (from ZT16 to ZT20), and were enriched in the Hif-1α signaling pathway and low-oxygen-related terms. Genes in Cluster 2 were predominantly involved in cilium assembly and organization and were relatively upregulated during the day. Genes in Cluster 3 were associated with ribosome biosynthesis and were highly expressed during the day-night transition period. Taken together, these results demonstrate that a large proportion of retinal genes are expressed rhythmically. Genes involved in energy production and glycolysis are highly expressed at night, leading to relative hypoxia and activation of the Hif-1α signaling pathway. Genes associated with the formation of photoreceptor cilia are expressed during the day.

Inhibition or Stimulation of Autophagy Affects Early Formation of Lipofuscin-Like Autofluorescence in the Retinal Pigment Epithelium Cell.

The accumulation of lipofuscin in the retinal pigment epithelium (RPE) is dependent on the effectiveness of photoreceptor outer segment material degradation. This study explored the role of autophagy in the fate of RPE lipofuscin degradation. After seven days of feeding with either native or modified rod outer segments, ARPE-19 cells were treated with enhancers or inhibitors of autophagy and the autofluorescence was detected by fluorescence-activated cell sorting. Supplementation with different types of rod outer segments increased lipofuscin-like autofluorescence (LLAF) after the inhibition of autophagy, while the induction of autophagy (e.g., application of rapamycin) decreased LLAF. The effects of autophagy induction were further confirmed by Western blotting, which showed the conversion of LC3-I to LC3-II, and by immunofluorescence microscopy, which detected the lysosomal activity of the autophagy inducers. We also monitored LLAF after the application of several autophagy inhibitors by RNA-interference and confocal microscopy. The results showed that, in general, the inhibition of the autophagy-related proteins resulted in an increase in LLAF when cells were fed with rod outer segments, which further confirms the effect of autophagy in the fate of RPE lipofuscin degradation. These results emphasize the complex role of autophagy in modulating RPE autofluorescence and confirm the possibility of the pharmacological clearance of RPE lipofuscin by small molecules.

Matrigel and Activin A promote cell-cell contact and anti-apoptotic activity in cultured human retinal pigment epithelium cells.

Age-related macular degeneration (AMD) is a leading cause of blindness among the aging population. Currently, replacement of diseased retinal pigment epithelium (RPE) cells with transplanted healthy RPE cells could be a feasible approach for AMD therapy. However, maintaining cell-cell contact and good viability of RPE cells cultured in vitro is difficult and fundamentally determines the success of RPE cell transplantation. This study was conducted to examine the role of Matrigel and Activin A (MA) in regulating cell-cell contact and anti-apoptotic activity in human RPE (hRPE) cells, as assessed by atomic force microscopy (AFM), scanning electron microscope (SEM), immunofluorescence staining, quantitative polymerase chain reaction (qPCR) analysis, Annexin V/propidium iodide (PI) analysis, mitochondrial membrane potential (â–³Ψ m) assays, intracellular reactive oxygen species (ROS) assays and Western blotting. hRPE cells cultured in vitro could maintain their epithelioid morphology after MA treatment over at least 4 passages. The contact of N-cadherin to the lateral cell border was promoted in hRPE cells at P2 by MA. MA treatment also enhanced the expression of tight junction-associated genes and proteins, such as Claudin-1, Claudin-3, Occludin and ZO-1, as well as polarized ZO-1 protein distribution and barrier function, in cultured hRPE cells. Moreover, MA treatment decreased apoptotic cells, ROS and Bax and increased â–³Ψ m and Bcl2 in hRPE cells under serum withdrawal-induced apoptosis. In addition, MA treatment elevated the protein expression levels of ß-catenin and its target proteins, including Cyclin D1, c-Myc and Survivin, as well as the gene expression levels of ZO-1, ß-catenin, Survivin and TCF-4, all of which could be down-regulated by the Wnt/ß-catenin pathway inhibitor XAV-939. Taken together, MA treatment could effectively promote cell-cell contact and anti-apoptotic activity in hRPE cells, partly involving the Wnt/ß-catenin pathway. This study will benefit the understanding of hRPE cells and future cell therapy.

DISTINGUISHING POLYPOIDAL CHOROIDAL VASCULOPATHY FROM TYPICAL NEOVASCULAR AGE-RELATED MACULAR DEGENERATION BASED ON SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY.

PURPOSE: To investigate the sensitivity and specificity of spectral domain optical coherence tomography in distinguishing polypoidal choroidal vasculopathy (PCV) from typical neovascular age-related macular degeneration (nAMD). METHODS: One hundred and eighty-eight eyes in 156 patients with active PCV or typical nAMD were enrolled prospectively. Three spectral domain optical coherence tomography manifestations, pigment epithelium detachment, double-layer sign, and thumb-like polyps were estimated in all the eyes. A diagnostic test to differentiate PCV from nAMD based on spectral domain optical coherence tomography was performed. Furthermore, the sensitivity and specificity was validated in a retrospective series of patients. RESULTS: Pigment epithelium detachment, double-layer sign, and thumb-like polyps were more common in PCV eyes than in nAMD eyes. When the cutoff point was set as at least 2 positive signs out of 3 in the diagnostic test, the sensitivity was 89.4% and specificity was 85.3%. The results of the validation test further confirmed the strategy, with satisfying sensitivity (87.5%) and specificity (86.2%). CONCLUSION: Spectral domain optical coherence tomography is sensitive and specific in distinguishing PCV from nAMD. From these results, the presence of at least two out three signs (pigment epithelium detachment, double-layer sign, and thumb-like polyps) indicates a positive test and is therefore suggested to be the screening strategy for PCV.

Comparison of intravitreal triamcinolone acetonide versus intravitreal bevacizumab as the primary treatment of clinically significant macular edema.

OBJECTIVES: To evaluate the short-term efficacy of triamcinolone acetonide versus bevacizumab for the treatment of diabetic, clinically significant, macular edema with different optical coherence tomography findings. METHODS: Fifty eyes of 45 consecutive patients with diabetic, clinically significant, macular edema were incorporated in this prospective interventional case series. Patients were divided into 3 groups according to findings on optical coherence tomography: 1) macular edema combined with serous retinal detachment (Group 1), 2) diffused macular thickening (Group 2), and 3) cystoid macular edema (Group 3). Patients from each group were treated with a single intravitreal injection of triamcinolone (IVTA) or 2 intravitreal injections of bevacizumab (IVB) with an interval of 6 weeks. Patients were observed at 6, 12, and 24 weeks after IVTA or the first IVB injection. Best-corrected visual acuity (BCVA) and central retinal thickness (CRT) were examined at each visit. Repeated-measures analysis of variance was used to compare the efficacy of the treatment groups. RESULTS: In Group 1, IVTA showed more favorable effects on CRT reduction and BCVA improvement compared with IVB at 6, 12, and 24 weeks (P = 0.002, 0.001, 0.027 and P = 0.036, 0.001, 0.027), respectively. In Group 2, IVB had more CRT reduction than IVTA at 6 and 12 weeks (P = 0.013 and 0.036), although there was no significant difference in BCVA improvement between the 2 groups (P > 0.05). In Group 3, IVTA and IVB did not have significant effects on CRT reduction and BCVA improvement (P > 0.05). CONCLUSION: The short-term efficacy of IVTA and IVB on treating clinically significant macular edema varied with different optical coherence tomography findings. In clinically significant macular edema combined with serous retinal detachment, IVTA may be more favorable than IVB in CRT reduction and BCVA improvement. In patients with diffused macular thickening, IVB may be better than IVTA in macular thickness reduction, although this does not translate to a significant improvement in BCVA.

[Progression of treatment and researches in dry age related macular degeneration].

Age related macular degeneration (AMD) is the leading cause of blindness and visual disability among old patients in Europe and North America. AMD has been divided into two broad clinical categories depending on whether there is a presence of abnormal neovascularization: neovascular (exudative or wet) AMD and dry (or geographic atrophic) AMD. VEGF has been understood as a pathogenesis of wet AMD which allows us to get breakthroughs in treatment. While the progression of dry AMD treatment is very slow because the lack of pathogenesis, no acute loss of vision, and without appropriate standards for treatment. This review tries to introduce about the recent researches and progressions for dry AMD treatment.

Effects of 5-aza-2'-deoxycytidine and trichostatin A on high glucose- and interleukin-1ß-induced secretory mediators from human retinal endothelial cells and retinal pigment epithelial cells.

PURPOSE: We aimed to elucidate the effects of two epigenetic inhibitors, 5-aza-2'-deoxycytidine (5-aza-dC) and trichostatin A (TSA), on several key secretory mediators of diabetic retinopathy (DR) in human retinal endothelial cells (HRECs) and human retinal pigment epithelial (HRPE) cells treated with high glucose or interleukin-1ß (IL-1ß). METHODS: HRECs and HRPE cells were incubated in 30 mM D-glucose or 10 ng/ml IL-1ß with or without the presence of various concentrations of 5-aza-dC or TSA. The production of pigment epithelium derived factor (PEDF), vascular endothelial cell growth factor (VEGF), intercellular cell adhesion molecule-1 (ICAM-1), IL-1ß, and matrix metalloproteinase 2 (MMP2) was evaluated at the mRNA and protein levels using real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: In the 30 mM D-glucose and the 10 ng/ml IL-1ß condition, the expression of VEGF, ICAM-1, IL-1ß, and MMP2 was induced in the HRECs and the HRPE cells. PEDF was downregulated in the HRPE cells but upregulated in the HRECs. However, the PEDF-to-VEGF ratio, which is thought to be critical in DR, was downregulated in both cell types. 5-aza-dC dose-dependently alleviated VEGF, ICAM-1, IL-1ß, and MMP2 and reversed PEDF or the PEDF/VEGF ratio in both cell types. TSA had similar effects as 5-aza-dC on the target mediators. However, ICAM-1 production was aggravated in the HRECs while remaining unchanged in the HRPE cells after TSA was administered. CONCLUSIONS: Our results demonstrated that 5-aza-dC and TSA enhance the protective PEDF and the PEDF/VEGF ratio and ameliorate the adverse effects of diabetic stimuli in vitro, suggesting that these two drugs may be of potential therapeutic value in DR.

Interleukin-4 and melatonin ameliorate high glucose and interleukin-1ß stimulated inflammatory reaction in human retinal endothelial cells and retinal pigment epithelial cells.

PURPOSE: We aimed to evaluate the effects of two immune regulatory factors, interleukin-4 (IL-4) and melatonin, on several inflammatory mediators that are involved in inflammation and angiogenesis in diabetic retinopathy (DR), in high glucose or interleukin-1ß (IL-1ß) induced primary human retinal endothelial cells (RECs) and human retinal pigment epithelial (RPE) cells. METHODS: Human RECs and RPE cells were cultured in 30 mM D-glucose or 10 ng/ml IL-1ß, with or without the presence of 40 ng/ml IL-4 or 100 µM melatonin. The mRNA and protein levels of vascular endothelial growth factor (VEGF), intercellular cell adhesion molecule-1 (ICAM-1), matrix metalloproteinases 2 (MMP2), and matrix metalloproteinases 9 (MMP9) were measured using real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. RESULTS: High glucose and IL-1ß induced the expression of VEGF, ICAM-1, MMP2, and MMP9 in human RECs and RPE cells. IL-4 and melatonin downregulated the expression of VEGF, ICAM-1, MMP2, and MMP9 induced by high glucose and IL-1ß. CONCLUSIONS: Our results demonstrated that IL-4 and melatonin inhibited inflammation and angiogenesis triggered by high glucose and IL-1ß, which suggests that these immune regulatory factors may be of potential therapeutic value in DR.

Safety and efficacy of conbercept in neovascular age-related macular degeneration: results from a 12-month randomized phase 2 study: AURORA study.

PURPOSE: To assess the safety and efficacy of multiple injections of 0.5 and 2.0 mg conbercept using variable dosing regimens in patients with neovascular age-related macular degeneration (AMD). DESIGN: Randomized, double-masked, multicenter, controlled-dose, and interval-ranging phase 2 clinical trial divided into a 3-month loading phase followed by a maintenance phase. PARTICIPANTS: Patients with choroidal neovascularization secondary to AMD with lesion sizes of 12 disc areas or less and a best-corrected visual acuity (BCVA) letter score of between 73 and 24 were enrolled. METHODS: Patients were randomized 1:1 to receive either 0.5 or 2.0 mg intravitreal conbercept for 3 consecutive monthly does. After the third dose, each group was reassigned randomly again to monthly (Q1M group) or as-needed (pro re nata [PRN] group) treatment without changing the drug assignment. MAIN OUTCOME MEASURES: The primary end point was the mean change in BCVA from baseline to month 3, with secondary end points being the mean change in BCVA, mean change in central retinal thickness (CRT), and safety at month 12. RESULTS: We enrolled 122 patients. At the primary end point at month 3, mean improvements in BCVA from baseline in the 0.5- and 2.0-mg groups were 8.97 and 10.43 letters, respectively. At month 12, mean improvements in BCVA from baseline were 14.31, 9.31, 12.42, and 15.43 letters for the 0.5-mg PRN, 0.5-mg Q1M, 2.0-mg PRN, and 2.0-mg Q1M regimens, respectively. At month 12, mean reductions in CRT in the 4 regimens were 119.8, 129.7, 152.1, and 170.8 µm, respectively. There were no significant differences for the pairwise comparisons between all study groups. The difference in the number of injections between the 2 PRN groups was not statistically significant. Treatment with conbercept generally was safe and well tolerated. CONCLUSIONS: The significant gains in BCVA at 3 months were the same or better at 12 months in all conbercept dosing groups of neovascular AMD patients. During the 12 months, repeated intravitreal injections of conbercept were well tolerated in these patients. Future clinical trials are required to confirm its long-term efficacy and safety.

Human adipose tissue-derived stem cell extracellular vesicles attenuate ocular hypertension-induced retinal ganglion cell damage by inhibiting microglia- TLR4/MAPK/NF-κB proinflammatory cascade signaling.

Microglia-mediated neuroinflammatory responses are recognized as a predominant factor during high intraocular pressure (IOP)-induced retinal and optic nerve injury along with potential therapeutic targets for the disease. Our previous research indicated that mesenchymal stem cell (MSC) treatment could reduce high IOP-induced neuroinflammatory responses through the TLR4 pathway in a rat model without apparent cell replacement and differentiation, suggesting that the anti-neuroinflammatory properties of MSCs are potentially mediated by paracrine signaling. This study aimed to evaluate the anti-neuroinflammatory effect of human adipose tissue-derived extracellular vesicles (ADSC-EVs) in microbead-induced ocular hypertension (OHT) animals and to explore the underlying mechanism since extracellular vesicles (EVs) are the primary transporters for cell secretory action. The anti-neuroinflammatory effect of ADSC-EVs on LPS-stimulated BV-2 cells in vitro and OHT-induced retinal and optic nerve injury in vivo was investigated. According to the in vitro research, ADSC-EV treatment reduced LPS-induced microglial activation and the TLR4/NF-κB proinflammatory cascade response axis in BV-2 cells, such as CD68, iNOS, TNF-α, IL-6, and IL-1ß, TLR4, p-38 MAPK, NF-κB. According to the in vivo data, intravitreal injection of ADSC-EVs promoted RGC survival and function, reduced microglial activation, microglial-derived neuroinflammatory responses, and TLR4/MAPK/NF-κB proinflammatory cascade response axis in the OHT mice. Our findings provide preliminary evidence for the RGC protective and microglia-associated neuroinflammatory reduction effects of ADSC-EVs by inhibiting the TLR4/MAPK/NF-κB proinflammatory cascade response in OHT mice, indicating the therapeutic potential ADSC-EVs or adjunctive therapy for glaucoma.

Development of an injectable oxidized dextran/gelatin hydrogel capable of promoting the healing of alkali burn-associated corneal wounds.

The cornea serves as an essential shield that protects the underlying eye from external conditions, yet it remains highly vulnerable to injuries that could lead to blindness and scarring if not promptly and effectively treated. Excessive inflammatory response constitute the primary cause of pathological corneal injury. This study aimed to develop effective approaches for enabling the functional repair of corneal injuries by combining nanoparticles loaded with anti-inflammatory agents and an injectable oxidized dextran/gelatin/borax hydrogel. The injectability and self-healing properties of developed hydrogels based on borate ester bonds and dynamic Schiff base bonds were excellent, improving the retention of administered drugs on the ocular surface. In vitro cellular assays and in vivo animal studies collectively substantiated the proficiency of probucol nanoparticle-loaded hydrogels to readily suppress proinflammatory marker expression and to induce the upregulation of anti-inflammatory mediators, thereby supporting rapid repair of rat corneal tissue following alkali burn-induced injury. As such, probucol nanoparticle-loaded hydrogels represent a prospective avenue to developing long-acting and efficacious therapies for ophthalmic diseases.