Retinopathy of prematurity (ROP) is a proliferative retinal vascular disease that threatens the vision of premature infants. Various novel drugs have demonstrated therapeutic potential for ROP by targeting signaling pathways associated with vascular endothelial growth factor (VEGF) [such as PI3K/AKT, hypoxia-inducible factor (HIF)-1α/VEGF], oxidative stress, tumor necrosis factor (TNF)-α, and Notch pathways. Propranolol, insulin-like growth factor-1, and celecoxib attenuate pathological neovascularization via the PI3K/Akt signaling pathway. Tripterine and melatonin inhibit retinal neovascularization by modulating the HIF-1α/VEGF signaling axis. Adiponectin mitigates the damage caused by oxidative stress and preserves endothelial function by enhancing endothelial nitric oxide synthase activity. Omega-3 polyunsaturated fatty acids suppress TNF-α-mediated inflammatory responses, modulate retinal development and angiogenesis, and reduce retinal neovascular lesions. DAPT, a γ-secretase inhibitor, blocks Notch signaling to suppress abnormal vascular proliferation. These agents exhibit synergistic multi-pathway anti-angiogenic effects in preclinical models and early-phase clinical trials, offering critical insights for advancing drug development and clinical translation in ROP management.
Retinopathy of Prematurity/metabolism* ; Humans ; Signal Transduction/drug effects* ; Infant, Newborn ; Vascular Endothelial Growth Factor A/metabolism* ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Tumor Necrosis Factor-alpha/metabolism* ; Oxidative Stress/drug effects* ; Fatty Acids, Omega-3/therapeutic use* ; Phosphatidylinositol 3-Kinases/metabolism* ; Proto-Oncogene Proteins c-akt/metabolism* ; Receptors, Notch/metabolism* ; Angiogenesis Inhibitors/therapeutic use* ; Insulin-Like Growth Factor I/therapeutic use*

Retinopathy of prematurity (ROP) is a vision-threatening disorder that leads to pathological growth of the retinal vasculature due to hypoxia. Here, we investigated the potential effects of alamandine, a novel heptapeptide in the renin-angiotensin system (RAS), on hypoxia-induced retinal neovascularization and its underlying mechanisms. In vivo, the C57BL/6J mice with oxygen-induced retinopathy (OIR) were injected intravitreally with alamandine (1.0 μmol/kg per eye). In vitro, human retinal microvascular endothelial cells (HRMECs) were utilized to investigate the effects of alamandine (10 μg/mL) on proliferation, apoptosis, migration, and tubular formation under vascular endothelial growth factor (VEGF) stimulation. Single-cell RNA sequencing (scRNA-seq) matrix data from the Gene Expression Omnibus (GEO) database and RAS-related genes from the Molecular Signatures Database (MSigDB) were sourced for subsequent analyses. By integrating scRNA-seq data across multiple species, we identified that RAS-associated endothelial cell populations were highly related to retinal neovascularization. The liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis revealed a significant decrease in alamandine levels in both the serum and retina of OIR mice compared to those in the control group. Next, alamandine ameliorated hypoxia-induced retinal pathological neovascularization and physiologic revascularization in OIR mice. In vitro, alamandine effectively mitigated VEGF-induced proliferation, scratch wound healing, and tube formation of HRMECs primarily by inhibiting the hypoxia-inducible factor-1α (HIF-1α)/VEGF pathway. Further, coincubation with D-Pro⁷ (Mas-related G protein-coupled receptor D (MrgD) antagonist) hindered the beneficial impacts of alamandine on hypoxia-induced pathological angiogenesis both in vivo and in vitro. Our findings suggested that alamandine could mitigate retinal neovascularization by targeting the MrgD-mediated HIF-1α/VEGF pathway, providing a potential therapeutic agent for OIR prevention and treatment.
Animals ; Retinal Neovascularization/prevention & control* ; Mice, Inbred C57BL ; Vascular Endothelial Growth Factor A/metabolism* ; Humans ; Mice ; Hypoxia-Inducible Factor 1, alpha Subunit/metabolism* ; Oligopeptides/therapeutic use* ; Signal Transduction/drug effects* ; Cell Proliferation/drug effects* ; Endothelial Cells/drug effects* ; Retinopathy of Prematurity/drug therapy* ; Apoptosis/drug effects* ; Cell Movement/drug effects* ; Renin-Angiotensin System/drug effects* ; Cells, Cultured

Objective To explore the role of the base mismatch repair gene Mutyh in retinopathy of prematurity(ROP). Methods Mutyh(-/-)and wild-type(WT)mice were used for the modeling of oxygen-induced retinopathy.The retinal oxidative stress was examined,and the ultrastructures of photoreceptors and mitochondria were observed.The biomarkers of photoreceptors and mitochondria were tested.Furthermore,the photoreceptor cell line 661W was treated with hydrogen peroxide for the modeling of oxidative stress.In the cell model,and the oxidative stress and photoreceptor functions in the cells were measured. Results In both the mouse and cell models,the expression of Mutyh was up-regulated.Mutyh knockout in mice and knockdown in cells exerted negative effects on photoreceptors and mitochondria.Mutyh overexpression showed protective functions in the cell model,indicating that Mutyh played a role in repairing photoreceptors and mitochondria. Conclusions Mutyh showed the potential to become a biomarker of ROP.Increasing Mutyh expression might have therapeutic effects on ROP,which needs further validation.
Oxidative Stress ; Animals ; Mice ; DNA Glycosylases/metabolism* ; Retinopathy of Prematurity/etiology* ; Mice, Knockout ; Disease Models, Animal ; Humans ; Mitochondria/metabolism*

OBJECTIVETo explore the effects of rat bone mesenchymal stem cell (BMSC) transplantation on retinal neovascularization, and to observe the changes of hypoxia-inducible factor-1 alpha (HIF-1α) and vascular endothelial growth factors (VEGF) in rats with oxygen-induced retinopathy (OIR).

METHODSSeventy-two seven-day-old Sprague-Dawley rats were randomly divided into three groups: normal control (CON), model (OIR) and BMSC transplantation. In the BMSC transplantation group, BMSCs were transplanted 5 days after oxygen conditioning. The phosphate buffered saline of the same volume was injected in the CON and OIR groups. The OIR model was prerpared according to the classic hyperoxygen method. At seven days after transplantation, retinal neovascularization was examined by retinal flat-mount staining and hematoxylin eosin (HE) staining. The expression of HIF-1α and VEGF proteins was examined by immunohistochemistry staining and Western blot analysis.

RESULTSThe retinal flat-mount staining results showed that the vessels were well organized in the CON group, but the vessels were irregularly organized, and lots of nonperfusion areas were observed in the OIR group. The large vessels were a bit circuitous, the retinal vessels were relatively organized, and less nonperfusion areas were noted in the BMSC transplantation group. The HE staining results showed that many neovessels and preretinal neovascular (pre-RNC) cells were observed on the internal limiting membrane in the OIR group. There were less pre-RNC cells in the BMSC transplantation group compared with the OIR group (P<0.01). The immunohistochemistry analysis showed that more HIF-1αand VEGFcells were observed in the OIR group compared with the CON group, and less HIF-1αand VEGFcells were observed in the BMSC transplantation group compared with OIR group (P<0.05). The Western blot analysis showed the expression of HIF-1α and VEGF proteins in the OIR group was significantly higher than that in the CON group. The expression of HIF-1α and VEGF proteins in the BMSC transplantation group was lower than that in the OIR group (P<0.01).

CONCLUSIONSBMSC transplantation therapy could alleviate retinal neovascularization in OIR rats, and its mechanisms might be associated with the inhibition of the expression of HIF-1α and VEGF proteins.

Animals ; Animals, Newborn ; Female ; Hypoxia-Inducible Factor 1, alpha Subunit ; analysis ; Male ; Mesenchymal Stem Cell Transplantation ; Rats ; Rats, Sprague-Dawley ; Retina ; chemistry ; Retinal Neovascularization ; prevention & control ; Retinopathy of Prematurity ; metabolism ; therapy ; Vascular Endothelial Growth Factor A ; analysis

BACKGROUNDThis study was to examine the expression of total vascular endothelial growth factor (VEGF) and the anti-angiogenic VEGF 165 b isoform in the vitreous body of retinopathy of prematurity (ROP) patients, and to further study the role of the VEGF splicing in the development of ROP.

METHODSThis was a prospective clinical laboratory investigation study. All patients enrolled received standard ophthalmic examination with stage 4 ROP that required vitrectomy to collect the vitreous samples. The control samples were from congenital cataract patients. The expression of total VEGF and the anti-angiogenic VEGF 165 b were measured by enzyme-linked immunosorbent assay. Results were analyzed statistically using nonparametric tests.

RESULTSThe total VEGF level was markedly elevated in ROP samples while VEGF 165 b was markedly decreased compared to control group. The relative protein expression level of VEGF 165 b isoform was significantly decreased in ROP patients which were correlated with the ischemia-induced neovascularization.

CONCLUSIONSThere was a switch of VEGF splicing from anti-angiogenic to pro-angiogenic family in ROP patients. A specific inhibitor that more selectively targets VEGF 165 and controls the VEGF splicing between pro- and anti-angiogenic families might be a more effective therapy for ROP.

Enzyme-Linked Immunosorbent Assay ; Female ; Humans ; Infant, Newborn ; Infant, Premature ; Male ; Prospective Studies ; Protein Isoforms ; metabolism ; Retinopathy of Prematurity ; metabolism ; Vascular Endothelial Growth Factor A ; metabolism ; Vitreous Body ; metabolism

OBJECTIVETo explore an optimal oxygen saturation for extremely preterm infants based on a systemic review of the published studies.

METHODSA Meta analysis of the published studies by the NeOProM Group which compared the outcomes of extremely preterm infants (gestational age <28 weeks) maintained in either a low (85%-89%) or high (91%-95%) oxygen saturation (SpO2) by using the STATA 12.0. The outcomes measured included the mortality and the incidences of retinopathy of prematurity (ROP), necrotizing enterocolitis of newborn (NEC), broncho-pulmonary dysplasia (BPD), intraventricular hemorrhage (IVH) and patent ductus arteriosus (PDA).

RESULTSThree studies were included, in which 2 460 infants were assigned into the low SpO2 group and 2 459 infants in the high SpO2 group. The Meta analysis demonstrated that the risk of mortality before discharge or at the age of 18 months increased in the low SpO2 group compared with the high SpO2 group (RR: 1.19; 95%CI: 1.05-1.35); the risk of ROP decreased in the low SpO2 group (RR: 0.73; 95%CI: 0.53-1.00); the risk of NEC increased in the low SpO2 group (RR: 1.26; 95%CI: 1.06-1.49). There was no significance in the incidences of BPD, IVH and PDA between the two groups.

CONCLUSIONSMaintaining SpO2 at 85%-89% may decrease the incidence of ROP, but increase the mortality rate and the incidence of NEC in extremely premature infants.

Enterocolitis, Necrotizing ; etiology ; Humans ; Infant ; Infant Mortality ; Infant, Extremely Premature ; metabolism ; Outcome Assessment (Health Care) ; Oxygen ; blood ; Retinopathy of Prematurity ; etiology

INTRODUCTIONRetinopathy of prematurity (ROP) can lead to severe visual impairment. This study was conducted to determine the levels of biochemical mediators (i. e. vascular endothelial growth f actor [ VEGF] and insulin- like growth factor-1 [IGF-1]) in the blood of premature infants with proliferative ROP.

METHODSBlood samples from 71 preterm infants born at or before 32 weeks of gestation were obtained 6-8 weeks after birth. These infants were classified into two groups according to their eye examination results. The control group consisted of 41 infants who had no evidence of ROP, and the study group consisted of 30 infants with proliferative ROP at stage III or higher. Blood VEGF and IGF-1 levels were measured using enzyme-linked immunosorbent assay.

RESULTSThe mean gestational ages of the infants at birth were 28.4 ± 1.6 and 28.8 ± 1.6 weeks in the study and control groups, respectively (p = 0.259). The mean postmenstrual age of the infants at the time of blood sampling was 34.9 ± 1.2 weeks in the study group and 34.6 ± 1.3 weeks in the control group (p = 0.339). The mean blood IGF-1 (18.48 ± 11.79 µg/L and 16.75 ± 13.74 µg/L in the study and control groups, respectively; p = 0.580) and VEGF (267.35 ± 103.43 pg/mL and 237.52 ± 130.92 pg/mL in the study and control groups, respectively; p = 0.305) levels of the infants were not significantly different between the two groups.

CONCLUSIONAt 6-8 weeks after birth, blood IGF-1 and VEGF levels were not found to be significantly different between premature infants with proliferative ROP and those without.

Case-Control Studies ; Enzyme-Linked Immunosorbent Assay ; Female ; Gestational Age ; Humans ; Infant, Newborn ; Infant, Premature ; Insulin-Like Growth Factor I ; metabolism ; Intensive Care, Neonatal ; Male ; Pulmonary Surfactants ; therapeutic use ; Retinopathy of Prematurity ; blood ; Vascular Endothelial Growth Factor A ; blood

OBJECTIVETo explore the effects of marrow mesenchymal stem cell (BMSC) transplantation on retinal cells apoptosis and changes to neurotrophin-3 (NT-3 and ciliary neurotrophic factor (CNTF) in rats with retinopathy of prematurity (ROP).

METHODSSeven-day-old Sprague-Dawley rats were randomly divided into normal control (CON), ROP, BMSC transplantation (BMSCs were transplanted 5 days after oxygen conditioning) and phosphate buffered saline (PBS) groups. The ROP model was prepared according to the classic hyperoxygen method. Seven days after transplantation, TUNEL/DAPI, NT-3/API and CNTF/DAPI double-labeled immunofluorescence were used to examine the effects of BMSC transplantation on both the apoptosis of retinal cells and the expression of NT-3 and CNTF protein in the retinal cells of the ROP rats.

RESULTSSeven days after BMSC transplantation, there were few TUNEL+ DAPI+ cells observed in the CON group. There were fewer TUNEL+DAPI+ cells observed in the BMSC group than in the ROP group (P<0.01), but there was no significant difference between the ROP and PBS groups (P>0.05). There were few NT-3+DAPI+ cells and CNTF+DAPI+ cells in the CON group. There were more NT-3+DAPI+ and CNTF+DAPI+ cells in the ROP group than in the CON group, but there was no significant difference between the ROP and CON groups (P>0.05). More NT-3+DAPI+ and CNTF+DAPI+ cells were observed in the BMSC group compared with the ROP group (P<0.01), and there was no significant difference in either NT-3+DAPI+ or CNTF+DAPI+ cells between the ROP and PBS groups (P>0.05).

CONCLUSIONSBMSC transplantation therapy could alleviate the apoptosis of retinal cells in ROP rats, and its mechanisms might be associated with promoting the expression of NT-3 and CNTF protein in retinal cells.

Animals ; Apoptosis ; Bone Marrow Cells ; physiology ; Cell Proliferation ; Ciliary Neurotrophic Factor ; analysis ; Female ; Humans ; In Situ Nick-End Labeling ; Infant, Newborn ; Male ; Mesenchymal Stem Cell Transplantation ; Neurotrophin 3 ; analysis ; Rats ; Rats, Sprague-Dawley ; Retina ; pathology ; Retinopathy of Prematurity ; metabolism ; therapy

PURPOSE: Retinopathy of prematurity (ROP) is one of the leading causes of blindness, with retinal detachment occurring due to oxygen toxicity in preterm infants. Recently, advances in neonatal care have led to improved survival rates for preterm infants, and ROP has increased in incidence. In the present study, we aimed to determine whether or not resveratrol exhibits protective effects in an animal model of ROP and in primary retinal cell cultures of neonatal rat via nitric oxide (NO)-modulating actions using western blotting and real-time PCR with inducible nitric oxide synthase (iNOS), endothelial NOS (eNOS) and neuronal NOS (nNOS) antibodies and mRNAs. METHODS: In an in vivo oxygen-induced retinopathy (OIR) model, cyclic hyperoxia was induced with 80% O2 for one day and 21% O2 for one day from P1 to P14 in newborn Sprague-Dawley (SD) rats. Resveratrol was injected intravitreally for seven days and rats were sacrificed at P21. In vitro OIR primary retinal cell culture was performed using P0-2 SD rats. Hyperoxia injuries were induced through 100% O2 exposure for six hours. Western blotting and real-time PCR using iNOS, eNOS, nNOS antibodies and primers were performed in the rat model of ROP and the dispersed retinal cell culture. RESULTS: In both in vivo and in vitro OIR, the expression of iNOS antibody and mRNA was increased and of eNOS and nNOS were reduced in the resveratrol-treated group. CONCLUSIONS: In conclusion, resveratrol appeared to exert retinal protective effects via modulation of NO-mediated mechanism in in vivo and in vitro OIR models.
Analysis of Variance ; Animals ; Animals, Newborn ; Blotting, Western ; Disease Models, Animal ; Electrophoresis, Polyacrylamide Gel ; Humans ; Infant, Newborn ; Nitric Oxide Synthase/*metabolism ; Oxygen/toxicity ; RNA/metabolism ; RNA, Messenger/metabolism ; Rats ; Rats, Sprague-Dawley ; Retina/drug effects/pathology ; Retinopathy of Prematurity/*metabolism/pathology/*prevention & control ; Reverse Transcriptase Polymerase Chain Reaction ; Stilbenes/*pharmacology

OBJECTIVETo explore VEGF siRNA's effect on the immature fetal retinal microvascular endothelial cells in vitro.

METHODThe fresh retinal micrangium was primarily cultured to obtain microvascular endothelial cells. CoCl2 was used to simulate oxygen-deficient conditions. siRNA directed against human VEGF was designed and chemically synthesized. There were 3 groups in our experiment: VEGF siRNA group, hypoxia control group, and negative siRNA control group. The fetal retinal micrangium vascular endothelial cells were transfected by using liposome. The expression levels of VEGF mRNA and protein were evaluated by RT-PCR and Western blotting 24, 48, 72 h after transfection, cell proliferation was evaluated by MTT method.

RESULTThe expression levels of VEGF mRNA decreased by 21.05%, 79.67%, and 90.48% 24 h, 48 h, and 72 h after transfection as compared to those in hypoxia control group, the expression level of VEGF protein had decreased by 14.58%, 66.97%, and 81.61% as compared to those in hypoxia control group. The siRNA could decrease cell proliferation under hypoxia too, the multiplication rate after 12, 24, 48, and 72 h decreased by 15.0%, 42.9%, 78.3% and 65.9%.

CONCLUSIONVEGF siRNA could down-regulate the expression of VEGF in immature fetal retinal microvascular endothelial cells and suppressed cell proliferation. Application of siRNA to inhibit expression of VEGF may be a hopeful way to prevent and cure ROP.

Cell Hypoxia ; Cell Line ; Endothelial Cells ; metabolism ; Humans ; Infant, Newborn ; RNA, Messenger ; genetics ; RNA, Small Interfering ; Retina ; metabolism ; pathology ; Retinal Vessels ; cytology ; metabolism ; Retinopathy of Prematurity ; metabolism ; Transfection ; Vascular Endothelial Growth Factor A ; genetics ; metabolism