ABSTRACT
Compromised vascular endothelial barrier function is a salient feature of diabetic complications such as sight-threatening diabetic macular edema (DME). Current standards of care for DME manage aspects of the disease, but require frequent intravitreal administration and are poorly effective in large subsets of patients. Here we provide evidence that an elevated burden of senescent cells in the retina triggers cardinal features of DME pathology and conduct an initial test of senolytic therapy in patients with DME. In cell culture models, sustained hyperglycemia provoked cellular senescence in subsets of vascular endothelial cells displaying perturbed transendothelial junctions associated with poor barrier function and leading to micro-inflammation. Pharmacological elimination of senescent cells in a mouse model of DME reduces diabetes-induced retinal vascular leakage and preserves retinal function. We then conducted a phase 1 single ascending dose safety study of UBX1325 (foselutoclax), a senolytic small-molecule inhibitor of BCL-xL, in patients with advanced DME for whom anti-vascular endothelial growth factor therapy was no longer considered beneficial. The primary objective of assessment of safety and tolerability of UBX1325 was achieved. Collectively, our data suggest that therapeutic targeting of senescent cells in the diabetic retina with a BCL-xL inhibitor may provide a long-lasting, disease-modifying intervention for DME. This hypothesis will need to be verified in larger clinical trials. ClinicalTrials.gov identifier: NCT04537884 .
Subject(s)
Diabetes Mellitus , Diabetic Retinopathy , Macular Edema , Animals , Mice , Humans , Macular Edema/drug therapy , Macular Edema/etiology , Diabetic Retinopathy/drug therapy , Angiogenesis Inhibitors/therapeutic use , Endothelial Cells , Senotherapeutics , Cellular SenescenceSubject(s)
Refractive Surgical Procedures , Retina , Humans , Retina/surgery , Genetic Therapy/methodsABSTRACT
BACKGROUND: The CLOSE study group proposes an updated surgical classification for large macular holes based on a systematic review of new treatments. Recently, many new techniques have been introduced to treat large full-thickness macular holes (FTMH); although the indications are not clear. An updated surgical classification is needed to help surgical decision-making. METHODS: We gathered published series by the CLOSE Study Group members and from literature search until June 2021. Techniques included: internal limiting membrane peeling (ILM peeling), ILM flaps, macular hydrodissection (macular hydro), human amniotic membrane graft (hAM), and autologous retinal transplantation (ART). Within each technique, chi-square test assessed association between the minimal linear diameter (MLD) (in µm) and closure rate; the postoperative best-corrected visual acuity (BCVA) gains were compared among groups. RESULTS: Data extraction included 31 published articles: total of 1135 eyes. Eyes were divided into the following groups: ILM peel (n: 683), ILM Flap (n: 233), macular hydrodissection (n: 64), hAM (n: 59), and ART (n: 96). The initial BCVA and size were heterogenous between the groups. ILM peel showed the best results in large FTMH ≤ 535 µm (closure rate 96.8%); adjusted mean BCVA: 0.49 (LogMAR) with a statistical difference among groups. Large FTMH between 535 and 799 µm: ILM flap technique showed better results (closure rate 99.0%); adjusted mean BCVA: 0.67(LogMAR); also with a statistical difference. For large FTMH ≥ 800 µm more invasive techniques are required. Use of hAM, macular hydrodissection and ART showed higher closure rates for this category (100%, 83.3% and 90.5% respectively), and adjusted mean BCVA varied from 0.76 to 0.89. Although there was no statistical difference between those techniques for this group due to the smaller number of cases. CONCLUSIONS: The CLOSE study group demonstrated the potential usefulness of a new surgical classification for large FTMHs and propose OCT biomarkers for use in clinical practice and future research. This new classification demonstrated that Large (400-550 µm) and X-Large (550-800 µm) holes can be treated highly successfully with ILM peel and ILM flap techniques, respectively. Further studies are necessary for the larger FTMHs (XX-Large and Giant), using the CLOSE classification, in order to determine which technique is better suited for each hole size and characteristics.
ABSTRACT
PURPOSE: To determine the long-term anatomic outcomes and surgical complications of pars plana vitrectomy (PPV) and 4-point Gore-Tex-sutured Akreos AO60 intraocular lens (IOL) scleral fixation. DESIGN: Retrospective, multicenter, multisurgeon case series. PARTICIPANTS: Ninety-seven patients in tertiary eye care centers. METHODS: The patients underwent PPV and intraocular fixation of the Akreos AO60 IOL using Gore-Tex CV-8 sutures between January 2015 and April 2020. The inclusion criteria were aphakia, no capsular support, and a minimal 1 year of follow-up. MAIN OUTCOME MEASURES: Uncorrected visual acuity (VA), complication rates or types, and refraction. RESULTS: Data from 101 eyes of the 97 patients were analyzed (mean follow-up duration, 33.4 months; range, 12-62 months). The mean ± standard deviation uncorrected logarithm of the minimum angle of resolution VA improved from 1.04 ± 0.73 (20/200 Snellen equivalent) before surgery to 0.66 ± 0.65 (20/80) at 6 months after surgery (P < 0.001). The most prevalent complications included hypotony (12.9%), ocular hypertension (12.9%), corneal edema (8.9%), cystoid macular edema (6.9%), and vitreous hemorrhage (5.9%). Refraction was measured between 3 and 6 months after surgery, and 61.8% of the patients had spherical equivalent of ± 2.0 diopters. Most complications occurred in the first postoperative month and resolved spontaneously or with medical treatment. CONCLUSIONS: The results demonstrated that this surgical technique is well tolerated by the eyes, with a low complication rate in the long term. The rates of IOL opacification were infrequent for up to 62 months of follow-up.
Subject(s)
Lens Implantation, Intraocular , Lenses, Intraocular , Humans , Lens Implantation, Intraocular/methods , Vitrectomy/methods , Retrospective Studies , PolytetrafluoroethyleneABSTRACT
BACKGROUND: To evaluate the rate and risk factors of epiretinal membrane (ERM) formation and need for ERM peeling after pars plana vitrectomy (PPV) for uncomplicated primary rhegmatogenous retinal detachment (RRD). METHODS: Retrospective, single-center, cohort study of 119 consecutive patients (119 eyes) that underwent RRD repair using PPV. The primary outcomes were ERM formation, classified using an optical coherence tomography grading system, and the rate of ERM peeling. Visual acuity, postoperative complications, and risk factors for ERM formation and peeling were also identified. RESULTS: Postoperative ERM formation occurred in 69 eyes (58.0%); 56 (47.1%) were stage 1, 9 (7.6%) stage 2, 3 (2.5%) stage 3, and 1 (0.8%) stage 4. Only 6 (5.0%) eyes required secondary PPV for a visually significant ERM, with a mean time to reoperation of 488 ± 351 days. Risk factors for ERM formation included intraoperative cryotherapy, more than 1000 laser shots, 360° laser photocoagulation, and choroidal detachment (p < 0.01). Eyes with more than 3 tears had a trend towards increased ERM surgery (p = 0.10). CONCLUSIONS: Visually significant ERM formation following PPV for primary RRD was uncommon in this cohort (5%). Half of the ERMs were detected after the first post-operative year, indicating that this complication may be underreported in studies with only 1-year follow-up.
ABSTRACT
Dyslipidemia and autophagy have been implicated in the pathogenesis of blinding neovascular age-related macular degeneration (NV-AMD). VLDL receptor (VLDLR), expressed in photoreceptors with a high metabolic rate, facilitates the uptake of triglyceride-derived fatty acids. Since fatty acid uptake is reduced in Vldlr-/- tissues, more remain in circulation, and the retina is fuel deficient, driving the formation in mice of neovascular lesions reminiscent of retinal angiomatous proliferation (RAP), a subtype of NV-AMD. Nutrient scarcity and energy failure are classically mitigated by increasing autophagy. We found that excess circulating lipids restrained retinal autophagy, which contributed to pathological angiogenesis in the Vldlr-/- RAP model. Triglyceride-derived fatty acid sensed by free fatty acid receptor 1 (FFAR1) restricted autophagy and oxidative metabolism in photoreceptors. FFAR1 suppressed transcription factor EB (TFEB), a master regulator of autophagy and lipid metabolism. Reduced TFEB, in turn, decreased sirtuin-3 expression and mitochondrial respiration. Metabolomic signatures of mouse RAP-like retinas were consistent with a role in promoting angiogenesis. This signature was also found in human NV-AMD vitreous. Restoring photoreceptor autophagy in Vldlr-/- retinas, either pharmacologically or by deleting Ffar1, enhanced metabolic efficiency and suppressed pathological angiogenesis. Dysregulated autophagy by circulating lipids might therefore contribute to the energy failure of photoreceptors driving neovascular eye diseases, and FFAR1 may be a target for intervention.
Subject(s)
Macular Degeneration , Retinal Neovascularization , Animals , Autophagy , Cell Proliferation , Fatty Acids , Macular Degeneration/pathology , Mice , Neovascularization, Pathologic , Receptors, G-Protein-Coupled , Retinal Neovascularization/pathology , TriglyceridesSubject(s)
Humans , Vitreoretinal Surgery , Surgeons , Ophthalmologists , Retina/surgery , Retinal Diseases/surgery , Vitreous Body/surgerySubject(s)
Humans , Vitreoretinal Surgery , Surgeons , Ophthalmologists , Retina/surgery , Retinal Diseases/surgeryABSTRACT
PURPOSE: To present a case of stellate nonhereditary idiopathic foveomacular retinoschisis (SNIFR) resolution associated with vitreomacular adherence (VMA) release and propose a potential contributing association between SNIFR and vitreomacular interactions. OBSERVATIONS: A 67-year-old female patient was diagnosed and followed for SNIFR in OD with spectral-domain optical coherence tomography (SD-OCT) scans at presentation and subsequent visits at 3, 6, 16 and 22 months. VMA and foveomacular retinoschisis remained unchanged on SD-OCT during the first 6 months of the follow-up. At 16-month follow-up visit, SD-OCT revealed VMA release and an important improvement of the macular schisis. At 22 months of follow-up, SNIFR cavities completely resolved in the presence of posterior hyaloid separation from the macular area without any adjunct treatment. The authors could not identify any other possible cause to justify the resolution of SNIFR other than VMA release in this case. Patient did not undergo any treatment for OD other than phacoemulsification 3 months after initial visit. CONCLUSION: The present case illustrates with SD-OCT scans a possible association between SNIFR resolution and VMA release, highlighting a potential tractional component of the posterior vitreous on the internal limiting membrane and consequent glial cells stretching with schisis formation.
ABSTRACT
BACKGROUND: The purpose of the current study is to report the anatomical and functional results of off-label human amniotic membrane graft as primary intervention to repair large to giant macular holes and in reoperations when wide internal limiting membrane peeling was unsuccessful. METHODS: Retrospective chart review was carried out in five different centers to identify all cases that had undergone off-label human amniotic membrane graft for the treatment of large or failed macular holes (MH). Data collected included age, gender, other concomitant diagnosis, symptoms duration, lens status, number of previous surgeries, macular hole measurements (minimum and base linear diameters), mean post-operative follow-up (months), and pre- and post-operative best corrected visual acuity (BCVA). Main outcome measures were anatomical MH closure rates and final BCVA (in logMAR). Nonparametric Wilcoxon rank-sum test was used because the data was not normally distributed, a P values < 0.05 were considered statistically significant. RESULTS: Nineteen eyes of 19 patients were identified and included in the study. Mean age was 66.21 ± 14.96 years and predominantly females (84%). All eyes had successfully closed MH with a single intervention with no recurrences during a mean of 9 ± 3.87 months follow-up. The median BCVA in logMAR preoperative was 1.30 ± 0.44 (0.80-2.0), approximately 20/400 on Snellen chart and the median BCVA in logMAR postoperative was 1.0 ± 0.72 (0.4-3.0) approximately 20/200 (p < 0.0001) with median of three lines of visual improvement. CONCLUSION: The use of human amniotic membrane graft seems to be a viable and effective alternative for the treatment of large and persistent macular holes. However, further larger prospective controlled studies are necessary to confirm our preliminary results of this new surgical technique.
ABSTRACT
Age-related macular degeneration (AMD) in its various forms is a leading cause of blindness in industrialized countries. Here, we provide evidence that ligands for neuropilin-1 (NRP1), such as Semaphorin 3A and VEGF-A, are elevated in the vitreous of patients with AMD at times of active choroidal neovascularization (CNV). We further demonstrate that NRP1-expressing myeloid cells promote and maintain CNV. Expression of NRP1 on cells of myeloid lineage is critical for mitigating production of inflammatory factors such as IL6 and IL1ß. Therapeutically trapping ligands of NRP1 with an NRP1-derived trap reduces CNV. Collectively, our findings identify a role for NRP1-expressing myeloid cells in promoting pathological angiogenesis during CNV and introduce a therapeutic approach to counter neovascular AMD.
Subject(s)
Choroidal Neovascularization , Wet Macular Degeneration , Angiogenesis Inhibitors , Humans , Inflammation , Neuropilin-1/genetics , Vascular Endothelial Growth Factor A , Visual AcuityABSTRACT
PURPOSE: To report the anatomic and functional outcomes of autologous retinal transplantation (ART). DESIGN: Multicenter, retrospective, interventional, consecutive case series. PARTICIPANTS: One hundred thirty eyes of 130 patients undergoing ART for the repair of primary and refractory macular holes (MHs), as well as combined MH-rhegmatogenous retinal detachment (MH-RRD), between January 2017 and December 2019. METHODS: All patients underwent pars plana vitrectomy and ART, with surgeon modification of intraoperative variables. A large array of preoperative, intraoperative, and postoperative data was collected. Two masked reviewers graded OCT images. Multivariate statistical analysis and subgroup analysis were performed. MAIN OUTCOME MEASURES: Macular hole closure rate, visual acuity (VA), external limiting membrane and ellipsoid zone (EZ) band integrity, and alignment of neurosensory layers (ANL) on OCT. RESULTS: One hundred thirty ART surgeries were performed by 33 vitreoretinal surgeons worldwide. Patient demographics were: mean age of 63 ± 6.3 years, 58% female, 41% White, 23% Black, 19% Asian, and 17% Latino. Preoperative VA was 1.37 ± 0.12 logarithm of the minimum angle of resolution (logMAR; Snellen equivalent, approximately 20/500), which improved significantly to 1.05 ± 0.09 logMAR (Snellen equivalent, approximately 20/225; P < 0.001) after surgery (mean follow-up, 8.6 ± 0.8 months). Autologous retinal transplantation was performed for primary MH repair in 27% of patients (n = 35), for refractory MH in 58% of patients (n = 76; mean number of previous surgeries, 1.6 ± 0.2), and for MH-RRD in 15% of patients (n = 19). Mean maximum MH diameter was 1470 ± 160 µm, mean minimum diameter was 840 ± 94 µm, and mean axial length was 24.6 ± 3.2 mm. Overall, 89% of MHs closed (78.5% complete; 10% small eccentric defect), with a 95% closure rate in MH-RRD (68.4% complete; 26.3% small eccentric defect). Visual acuity improved by at least 3 lines in 43% of eyes and by at least 5 lines in 29% of eyes. Reconstitution of the EZ (P = 0.02) and ANL (P = 0.01) on OCT were associated with better final VA. Five cases of ART graft dislocation (3.8%), 5 cases of postoperative retinal detachment (3.8%), and 1 case of endophthalmitis (0.77%) occurred. CONCLUSIONS: In this global experience, patients undergoing ART for large primary and refractory MHs and MH-RRDs achieved good anatomic and functional outcomes, with low complication rates despite complex surgical pathologic features.
Subject(s)
Retina/transplantation , Retinal Detachment/surgery , Retinal Perforations/surgery , Aged , Basement Membrane/physiology , Female , Follow-Up Studies , Global Health , Humans , Male , Middle Aged , Retinal Detachment/diagnosis , Retinal Detachment/physiopathology , Retinal Perforations/diagnosis , Retinal Perforations/physiopathology , Retrospective Studies , Tomography, Optical Coherence , Transplantation, Autologous , Treatment Outcome , Visual Acuity/physiology , VitrectomyABSTRACT
BACKGROUND/AIMS: To evaluate the non-invasive measurement of ocular rigidity (OR), an important biomechanical property of the eye, as a predictor of intraocular pressure (IOP) elevation after anti-vascular endothelial growth factor (anti-VEGF) intravitreal injection (IVI). METHODS: Subjects requiring IVI of anti-VEGF for a pre-existing retinal condition were enrolled in this prospective cross-sectional study. OR was assessed in 18 eyes of 18 participants by measurement of pulsatile choroidal volume change using video-rate optical coherence tomography, and pulsatile IOP change using dynamic contour tonometry. IOP was measured using Tono-Pen XL before and immediately following the injection and was correlated with OR. RESULTS: The average increase in IOP following IVI was 19±9 mm Hg, with a range of 7-33 mm Hg. The Spearman correlation coefficient between OR and IOP elevation following IVI was 0.796 (p<0.001), showing higher IOP elevation in more rigid eyes. A regression line was also calculated to predict the IOP spike based on the OR coefficient, such that IOP spike=664.17 mm Hg·µL×OR + 4.59 mm Hg. CONCLUSION: This study shows a strong positive correlation between OR and acute IOP elevation following IVI. These findings indicate that the non-invasive measurement of OR could be an effective tool in identifying patients at risk of IOP spikes following IVI.
Subject(s)
Bevacizumab/administration & dosage , Eye/physiopathology , Intraocular Pressure/physiology , Wet Macular Degeneration/drug therapy , Aged , Angiogenesis Inhibitors/administration & dosage , Cross-Sectional Studies , Elasticity , Female , Humans , Intraocular Pressure/drug effects , Intravitreal Injections , Male , Prospective Studies , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Wet Macular Degeneration/diagnosis , Wet Macular Degeneration/physiopathologyABSTRACT
In developed countries, the leading causes of blindness such as diabetic retinopathy are characterized by disorganized vasculature that can become fibrotic. Although many such pathological vessels often naturally regress and spare sight-threatening complications, the underlying mechanisms remain unknown. Here, we used orthogonal approaches in human patients with proliferative diabetic retinopathy and a mouse model of ischemic retinopathies to identify an unconventional role for neutrophils in vascular remodeling during late-stage sterile inflammation. Senescent vasculature released a secretome that attracted neutrophils and triggered the production of neutrophil extracellular traps (NETs). NETs ultimately cleared diseased endothelial cells and remodeled unhealthy vessels. Genetic or pharmacological inhibition of NETosis prevented the regression of senescent vessels and prolonged disease. Thus, clearance of senescent retinal blood vessels leads to reparative vascular remodeling.
Subject(s)
Aging/pathology , Diabetic Retinopathy/pathology , Extracellular Traps/immunology , Retinal Vessels/pathology , Animals , Cellular Senescence , Diabetic Retinopathy/immunology , Disease Models, Animal , Endothelial Cells/immunology , Endothelial Cells/pathology , Humans , Inflammation/immunology , Inflammation/pathology , Mice , Mice, Inbred C57BL , Neutrophils/immunology , Retinal Vessels/immunologyABSTRACT
BACKGROUND: Recurrent retinal detachment (RD) is still a widespread event despite the therapeutic options available. Proliferative vitreoretinopoathy (PVR) is one of the main causes of redetachment. Little is known about the use of endoscopy-assisted vitrectomy (E-PPV) in complex recurrent RD with PVR. The purpose of this study was to identify the potential advantages of E-PPV in complex RD with PVR compared with pars plana vitrectomy (PPV) alone. METHODS: Single-center, retrospective, observational, descriptive study. The medical records of 293 patients were reviewed. Patients who underwent PPV for complex rhegmatogenous RD and associated PVR between 2009 and 2017 were included. Patients with diabetic tractional RD, trauma, uveitis or detachment postendophthalmitis were excluded. After 2013, an endoscopic visualization system was used in a nonrandomized fashion at the surgeon's discretion. Outcome measures (reattachment rate, number of surgeries, lens status, PVR stage, intraocular pressure, phthisis rate) were compared between the E-PPV and PPV-only groups with independent samples t-tests (continuous variables) and Fisher's exact test (categorical variables), as well as time-adjusted analyses. Postoperative time to retinal redetachment was assessed with Kaplan-Meier survival analysis. RESULTS: One hundred one eyes from 100 patients met the inclusion criteria. The mean participant age was 63.3 years old (95% CI 60.4-66.1 years), without a significant difference between groups. E-PPV was performed in 36.6% (n = 37) of eyes, and 63.4% (n = 64) underwent PPV only. The mean follow-up was significantly longer in the PPV-only group (31.9 vs. 21.1 months; p = 0.021). Upon adjustment for follow-up duration, the mean number of surgeries was significantly lower in the PPV-only group (2.6 vs. 4.3 number of surgeries; p < 0.001) than in the E-PPV group. A significantly higher risk for redetachment was observed in the PPV-only group (HR [95% CI] 4.1 [1.4-11.8]) than in the E-PPV group (p = 0.037). The evolution to phthisis was 7% (n = 4) in the PPV-only group and 2.7% (n = 1) in the E-PPV group (p > 0.05). CONCLUSIONS: Compared to PPV alone, endoscopy-assisted vitrectomy seems to be advantageous in achieving better reattachment rates in complex RD with advanced PVR. Endoscopic visualization allows a thorough examination and extensive anterior PVR and vitreous base dissection.
ABSTRACT
PURPOSE: To analyze and provide an overview of the incidence, management, and prevention of conjunctival erosion in Argus II clinical trial subjects and postapproval patients. METHODS: This retrospective analysis followed the results of 274 patients treated with the Argus II Retinal Prosthesis System between June 2007 and November 2017, including 30 subjects from the US and European clinical trials, and 244 patients in the postapproval phase. Results were gathered for incidence of a serious adverse event, incidence of conjunctival erosion, occurrence sites, rates of erosion, and erosion timing. RESULTS: Overall, 60% of subjects in the clinical trial subjects versus 83% of patients in the postapproval phase did not experience device- or surgery-related serious adverse events. In the postapproval phase, conjunctival erosion had an incidence rate of 6.2% over 5 years and 11 months. In 55% of conjunctival erosion cases, erosion occurred in the inferotemporal quadrant, 25% in the superotemporal quadrant, and 20% in both. Sixty percent of the erosion events occurred in the first 15 months after implantation, and 85% within the first 2.5 years. CONCLUSION: Reducing occurrence of conjunctival erosion in patients with the Argus II Retinal Prosthesis requires identification and minimization of risk factors before and during implantation. Implementing inverted sutures at the implant tabs, use of graft material at these locations as well as Mersilene rather than nylon sutures, and accurate Tenon's and conjunctiva closure are recommended for consideration in all patients.
Subject(s)
Conjunctiva/surgery , Conjunctival Diseases/etiology , Postoperative Complications/etiology , Prosthesis Implantation/adverse effects , Retinitis Pigmentosa/surgery , Visual Prosthesis/adverse effects , Conjunctival Diseases/epidemiology , Conjunctival Diseases/prevention & control , Europe/epidemiology , Female , Humans , Incidence , Male , Middle Aged , Postoperative Complications/epidemiology , Postoperative Complications/prevention & control , Prosthesis Implantation/methods , Retrospective Studies , United States/epidemiologySubject(s)
Blindness/rehabilitation , Ocular Hypotension/etiology , Prosthesis Implantation/adverse effects , Retinitis Pigmentosa/therapy , Visual Prosthesis/adverse effects , Ciliary Body/injuries , Electrodes, Implanted , Eye Injuries/etiology , Humans , Incidence , Intraocular Pressure , Ocular Hypotension/prevention & control , Retrospective Studies , Sclerostomy/adverse effects , Wound Healing/physiologyABSTRACT
Pathological angiogenesis is the hallmark of diseases such as cancer and retinopathies. Although tissue hypoxia and inflammation are recognized as central drivers of vessel growth, relatively little is known about the process that bridges the two. In a mouse model of ischemic retinopathy, we found that hypoxic regions of the retina showed only modest rates of apoptosis despite severely compromised metabolic supply. Using transcriptomic analysis and inducible loss-of-function genetics, we demonstrated that ischemic retinal cells instead engage the endoplasmic reticulum stress inositol-requiring enzyme 1α (IRE1α) pathway that, through its endoribonuclease activity, induces a state of senescence in which cells adopt a senescence-associated secretory phenotype (SASP). We also detected SASP-associated cytokines (plasminogen activator inhibitor 1, interleukin-6, interleukin-8, and vascular endothelial growth factor) in the vitreous humor of patients suffering from proliferative diabetic retinopathy. Therapeutic inhibition of the SASP through intravitreal delivery of metformin or interference with effectors of senescence (semaphorin 3A or IRE1α) in mice reduced destructive retinal neovascularization in vivo. We conclude that the SASP contributes to pathological vessel growth, with ischemic retinal cells becoming prematurely senescent and secreting inflammatory cytokines that drive paracrine senescence, exacerbate destructive angiogenesis, and hinder reparative vascular regeneration. Reversal of this process may be therapeutically beneficial.
Subject(s)
Cellular Senescence , Diabetic Retinopathy/blood , Neovascularization, Pathologic , Retinal Vessels/pathology , Animals , Cell Line, Tumor , Cell Proliferation , Cytokines/metabolism , Diabetic Retinopathy/physiopathology , Endoplasmic Reticulum Stress , Endoribonucleases/metabolism , Female , HEK293 Cells , Humans , Male , Mice , Mice, Inbred C57BL , Oxygen/chemistry , Phenotype , Protein Serine-Threonine Kinases/metabolism , Retina/pathology , Retinal Neovascularization , Vascular Endothelial Growth Factor A/metabolism , VitrectomyABSTRACT
Diabetic retinopathy (DR) is a major complication of diabetes and a leading cause of blindness in the working-age population. Impaired blood-retinal barrier function leads to macular edema that is closely associated with the deterioration of central vision. We previously demonstrated that the neuronal guidance cue netrin-1 activates a program of reparative angiogenesis in microglia within the ischemic retina. Here, we provide evidence in both vitreous humor of diabetic patients and in retina of a murine model of diabetes that netrin-1 is metabolized into a bioactive fragment corresponding to domains VI and V of the full-length molecule. In contrast to the protective effects of full-length netrin-1 on retinal microvasculature, the VI-V fragment promoted vascular permeability through the uncoordinated 5B (UNC5B) receptor. The collagenase matrix metalloprotease 9 (MMP-9), which is increased in patients with diabetic macular edema, was capable of cleaving netrin-1 into the VI-V fragment. Thus, MMP-9 may release netrin-1 fragments from the extracellular matrix and facilitate diffusion. Nonspecific inhibition of collagenases or selective inhibition of MMP-9 decreased pathological vascular permeability in a murine model of diabetic retinal edema. This study reveals that netrin-1 degradation products are capable of modulating vascular permeability, suggesting that these fragments are of potential therapeutic interest for the treatment of DR.