Rapid resolution of severe retinal neovascularisation in proliferative diabetic retinopathy following adjunctive intravitreal bevacizumab (Avastin)

Angiogenic footprints in diabetic retinopathy: opportunities for drug development

Diabetic retinopathy is one of the withering disorders that has been making the lives of patients miserable. Arising as a result of chronic high blood sugar levels in diabetes patients, retinopathy has become a major reason causing permanent blindness, retinal detachment, vitreous humor, rage, or glaucoma among patients. Angiogenesis being the major culprit behind the development of this condition is the growth of new blood vessels from the earlier ones existing. The abnormal growth and poor development of blood vessels also lead to aggravation of the conditions, with vascular endothelial growth factor (VEGF) playing a major role in the process. Various anti-angiogenic therapies or anti-VEGF therapies are being explored for the treatment of this condition. 4 widely explored drugs being-Bevacizumab, pegaptanib sodium, ranibizumab, and aflibercept. The review article tries to summarize studies illustrating the efficacy of these drugs in the treatment of diabetic retinopathy along with some of the herbal therapeutic paradigms displaying anti-angiogenic action that is being used to treat this condition.

Anti-VEGF-Aptamer Modified C-Dots-A Hybrid Nanocomposite for Topical Treatment of Ocular Vascular Disorders

The vascular endothelial growth factor (VEGF) induces pathological angiogenetic ocular diseases. It is a scientific challenge to develop carriers for the controlled release of inhibitors for VEGF present in the back of the eye domain. Carbon dots (C-dots) functionalized with the VEGF aptamer are introduced and the hybrid nanoparticles are used for ocular nanomedicine. The C-dots are applied as effective carriers of the anti-VEGF aptamer across the cornea, yielding therapeutic levels upon topical administration. The hybrids show no toxicity for both in vitro and in vivo murine animal model, and further enable noninvasive intraocular concentration monitoring through the C-dots inherent fluorescence. In addition, the hybrid C-dots effectively inhibit VEGF-stimulated angiogenesis in choroidal blood vessels. This inhibition is comparable to two commercially available anti-VEGF drugs, bevacizumab and aflibercept. The hybrid aptamer-modified C-dots provide a versatile nanomaterial to treat age-related macular degeneration and diabetic retinopathy.

Correlation of serum CF6 with blood lipid and glucose in patients with type 2 diabetic retinopathy

This study was to investigate the relationship of serum mitochondrial coupling factor 6 (CF6) with blood lipid and glucose in patients with type 2 diabetic retinopathy. A total of 180 patients with type 2 diabetes enrolled in our hospital from January 2015 to September 2017 were selected as the research objects. They were divided in accordance with fundus fluorescence angiography (FFA) into normal diabetic retinopathy (NDR) group, background diabetic retinopathy (BDR) group as well as proliferative diabetic retinopathy (PDR), with 60 cases in each group, and at the same time, another 60 healthy subjects were selected as normal control (NC) group. Serum CF6, fasting plasma glucose (FPG), 2 h postprandial plasma glucose (2hPG), glycosylated hemoglobin (HbA1c), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol as well as triglyceride were measured in the groups and the relationship of serum CF6 with related indicators was analyzed. The level of serum CF6 in type 2 diabetes group was higher than that in NC group and there was statistically significant difference among the groups with the occurrence and aggravation of retinopathy ( P < 0.05). Correlation analysis showed that serum CF6 was positively correlated with FPG, 2hPG, HbA1c, and LDL-C of statistical significance ( P < 0.05) and negatively correlated with HDL-C of statistical significance ( P < 0.05). The results of multiple step regression analysis showed that HbA1c and LDL-C were independent risk factors for CF6. In conclusion, the serum CF6 of patients with diabetic retinopathy increases with aggravation of the disease, taking a part in the occurrence and development of retinopathy together with the disorder of blood glucose and lipid metabolism.

Expression and significance of SDF-1 and its receptor CXCR4 in the retina of pregnant rats after optic nerve injury

Stromal cell–derived factor 1 (SDF-1) and its receptor CXCR4 have shown to play a role in embryonic development process, regulation of hematopoiesis, mediating immunology response, inflammatory reaction, and metastasis of malignant tumor. Recently, SDF-1 and CXCR4 are also closely related to retinal neovascularization. This study was to investigate the expression of SDF-1 and CXCR4 in the retina after optic nerve injury in pregnant rats so as to reveal its significance. A total of 12 pregnant rats were randomly divided into normal group and experimental group (after 5 days of optic nerve injury), six rats in each group; expressions of SDF-1 as well as CXCR4 in rat retina were detected by immunofluorescence staining and western blot assay. The result of immunofluorescence staining showed that the relative gray scale values of SDF-1 and CXCR4 in the experimental group were significantly higher than those in the normal group ( P < 0.05), and the result of Western blot assay showed that the expression levels of SDF-1 and CXCR4 in the experimental group were significantly higher than those in the normal group ( P < 0.05). In conclusion, SDF-1 and its receptor CXCR4 have abnormal expression in the retina of pregnant rats after optic nerve injury, which may be involved in the occurrence and development of optic nerve injury.

Timing of neovascular regression in eyes with high-risk proliferative diabetic retinopathy without macular edema treated initially with intravitreous bevacizumab

Purpose

To determine the timing of neovascular regression after intravitreous injection of bevacizumab (Avastin^®) 1.25 mg given as initial therapy for eyes with high-risk proliferative diabetic retinopathy (PDR) without clinically significant macular edema (CSME).

Patients and methods

In this prospective uncontrolled interventional study, eyes with high-risk PDR without CSME were treated initially with intravitreous injections of bevacizumab 1.25 mg given every 4 weeks until no neovessels were detected, followed by standard pan-retinal photocoagulation (PRP). Patients were examined 48 hours, 1, 2, and 4 weeks after each injection to determine the status of neovascularization.

Results

Twenty-one patients (24 eyes) were included in the study. Forty-eight hours after the first injection of bevacizumab, we observed complete neovascular regression in 20 (83%) eyes. Neovascular regression was maintained in the same number of eyes in the first 2 weeks. At 4 weeks, three eyes displayed neovascular recurrence, and a second injection of bevacizumab was given to the seven eyes with persistent or recurrent neovascularization. Complete neovascular regression was observed in six (86%) eyes after 48 hours and was maintained for 2 weeks following the second bevacizumab injection. Two eyes required a third injection and had complete neovascular regression when assessed after 48 hours and 4 weeks.

Conclusion

The majority of neovessels completely regressed within 48 hours after intra-vitreous injection of bevacizumab given as initial therapy for high-risk PDR without CSME. The full neovascular regressive effect occurred within 48 hours and was maintained for at least 2 weeks.

Observation of optic disc neovascularization using OCT angiography in proliferative diabetic retinopathy after intravitreal conbercept injections

This study reports the short-term efficacy and safety of intravitreal conbercept injections for neovascularization at the disc (NVD) in patients with proliferative diabetic retinopathy (PDR). Conbercept is a recombinant fusion protein with a high affinity for all isoforms of vascular endothelial growth factor (VEGF)-A, placental growth factor and VEGF-B. A prospective case series study was conducted in 15 patients (15 eyes). Patients had complete ocular examinations and received a 0.5 mg intravitreal conbercept injection followed by supplemental pan-retinal photocoagulation (PRP). Optical coherence tomography angiography (OCTA) was performed before and after treatment. Before treatment, the mean NVD area was 1.05 ± 0.33 mm², and it decreased to 0.56 ± 0.17 mm² after an interval of 7.5 d (p = 0.000). One eye required vitrectomy during follow-up. Recurrent NVD was observed in 2 eyes, which resolved after repeated injections. The remaining 12 eyes were stable over a mean follow-up period of 8.3 months. The mean area of the NVD in 14 patients without vitrectomy was 0.22 ± 0.11 mm² (p = 0.000) at the last visit. Intravitreal conbercept injections combined with intensive PRP are an effective and safe treatment for PDR with NVD. Quantitative information on NVD can be obtained with OCTA, which may be clinically useful in evaluating the therapeutic effect.

INTRAVITREAL BEVACIZUMAB FOR PROLIFERATIVE DIABETIC RETINOPATHY: Results From the Pan-American Collaborative Retina Study Group (PACORES) at 24 Months of Follow-up

PURPOSE

To evaluate the effects of intravitreal bevacizumab (IVB) on retinal neovascularization in patients with proliferative diabetic retinopathy (PDR).

METHODS

Retrospective multicenter interventional case series. A chart review was performed of 81 consecutive patients (97 eyes) with retinal neovascularization due to PDR, who received at least 1 IVB injection.

RESULTS

The mean age of the patients was 55.6 ± 11.6 years. The mean number of IVB injections was 4 ± 2.5 injections (range, 1-8 injections) per eye. The mean interval between IVB applications was 3 ± 7 months. The mean duration of follow-up was 29.6 ± 2 months (range, 24-30 months). Best-corrected visual acuity and optical coherence tomography improved statistically significantly (P < 0.0001, both comparisons). Three eyes without previous panretinal photocoagulation ("naive" eyes) and with vitreous hemorrhage did not require vitreoretinal surgery. Five (5.2%) eyes with PDR progressed to tractional retinal detachment requiring vitrectomy. No systemic adverse events were noted.

CONCLUSION

Intravitreal bevacizumab resulted in marked regression of retinal neovascularization in patients with PDR and previous panretinal photocoagulation. Intravitreal bevacizumab in naive eyes resulted in control or regression of 42.1% of eyes without adjunctive laser or vitrectomy during 24 months of follow-up. There were no safety concerns during the 2 years of follow-up of IVB for PDR.

Vascular Endothelial Growth Factor Inhibitors for Diabetic Retinopathy

The prevalence of diabetes is growing at epidemic rates in the USA. Diabetic retinopathy develops in a large proportion of patients and is a leading cause of blindness worldwide. Systemic management of diabetic retinopathy has included glycemic, hypertension, and lipid control. Local ophthalmic treatment in the form of focal/grid or panretinal laser photocoagulation has been shown to prevent vision loss in diabetic edema and proliferative diabetic retinopathy, respectively. The introduction of anti-vascular endothelial growth factor for diabetic macular edema and retinopathy has provided clinicians with improved clinical outcomes with potentially less damaging effects than laser.

A review of anti-VEGF agents for proliferative diabetic retinopathy

Previous research has implicated vascular endothelial growth factor (VEGF) in the pathogenesis of diabetic retinopathy (DR). Although many studies reviewed the use of anti-VEGF for diabetic macular oedema, little has been written about the use of anti-VEGF for proliferative diabetic retinopathy (PDR). This study is a review of relevant publications dealing with the use of anti-VEGF for the treatment of PDR. The articles were identified through systematic searches of PUBMED and the Cochrane Central Register of Controlled Trials. At the end of each section, we summarized the level of evidence of the scientific literature. Off-label use of anti-VEGF agents was found to be beneficial in PDR, especially in cases with neovascular glaucoma, persistent vitreous haemorrhage, and before vitrectomy. The disadvantages of the use of anti-VEGF are its short-effect duration, causing tractional retinal detachment in cases with pre-existing pre-retinal fibrosis and endophthalmitis in rare cases. There is no conclusive evidence from large randomized trials regarding the efficacy of anti-VEGF treatment in PDR. However, numerous case series, sound biochemical mechanism of action, and increasing experience with using anti-VEGF drugs can be used to support the ongoing use of this treatment modality in selected patients.

Intravitreal bevacizumab in the treatment of diabetic ocular neovascularization

PURPOSE

To evaluate the efficacy of intravitreal bevacizumab for treating diabetic retinal and/or iris neovascularization.

METHODS

Consecutive, prospective, interventional case series study of 60 eyes with diabetic retinal and/or iris neovascularization. Patients had a complete ocular examination before receiving 1.25 mg (0.05 mL) of intravitreal bevacizumab. Abnormal new vessels elsewhere in the retina, optic disk, or iris were graded by size and associated hemorrhage or glaucoma. Patients had complete postinjection ophthalmic evaluations with regrading of the abnormal new vessels at 3 months and 6 months. The main outcome measures included clinical partial or total regression of abnormal new vessels, changes in visual acuity, and complications related to the intravitreal injections.

RESULTS

Twenty-six patients (47.3%) were men (mean age, 59 years). Abnormal new vessel regression at 6 months occurred in 65% of new vessels of the iris (P = 0.001), 45% of new vessels of the optic disk (P = 0.009), and 43% of new vessels elsewhere (P = 0.008). The visual acuity improved in 20% of eyes, which was not significant (P = 0.235); the visual acuity deteriorated in 23% of eyes (P = 0.163). No systemic or ocular side effects developed except for postinjection hypotony in one eye.

CONCLUSION

Intravitreal bevacizumab is a well-tolerated medication that causes regression of abnormal diabetic neovascularization. New vessels of the iris responded more than new vessels of the optic disk and new vessels elsewhere.

The role of angiogenesis in the development of proliferative diabetic retinopathy: impact of intravitreal anti-VEGF treatment

Although cellular and molecular bases of proliferative diabetic retinopathy are only partially understood, it is evident that this complication of diabetes is characterized by the formation of new vessels inside the retina showing abnormal architecture and permeability. This process, if not controlled by selective laser photocoagulation, leads to irreversible retinal damages and loss of vision. Angiogenesis, that is, the condition characterized by the growth of new blood vessels originated from preexisting ones, was shown to have a major role in the pathogenesis of proliferative retinopathy and, as a consequence, intravitreal antiangiogenic injection was suggested as a feasible treatment for this disease. Here, we describe the different antiangiogenic approaches used to treat this disease along with the respective advantages and limitations when compared to laser treatment. Altogether, even though further and longer studies are still needed to clarify the best possible therapeutic protocol, the antiangiogenic treatment will reasonably have a future role in the therapy and prevention of proliferative diabetic retinopathy.

Treatment of proliferative diabetic retinopathy with anti-VEGF agents

Proliferative diabetic retinopathy (PDR) is the most common cause of severe visual loss in people with diabetes. Although panretinal photocoagulation (PRP) remains the gold standard of care to date, several combinations of new treatment modalities have emerged. These approaches can be used to increase the extent of treatment, expedite the effect of laser treatment and provide alternate measures when laser delivery is difficult or impossible, especially in patients with vitreous haemorrhage. Currently, most of the research in this field is focussed on inhibitors of vascular endothelial growth factor (VEGF), referred to herein as anti-VEGF agents. Although limited by their short-lived effects and a lack of established protocols, anti-VEGF agents are widely available, especially for the treatment of aggressive PDR. This review analyses published studies using anti-VEGF agents alone or as an adjunct to other therapies in the treatment of PDR.

Proliferative diabetic retinopathy: predictive and preventive measures at hypoxia induced retinal changes

Retinal vasculature changes in diabetic patients are most common cause of blindness among eye diseases. Numerous studies have explored the role of the agiogenic factors in the progression of diabetic retinopathy (DR). The balance between angiogenic and antiangiogenic factors has a determining role in the DR progression. Current treatment modalities include laser photocoagulation, intravitreal drug application, and pars plana vitrectomy (ppv). These maneuvers are employed with occurrence of advanced retinal changes. New diagnostic approaches can provide better information for the initial retinal changes thereby requiring a new DR classification and treatment guidelines. The results that are expected from Diabetic Retinopathy Clinical Research Network (DRCR) are at the level where prediction and prevention can not be made. Innovative molecular-imaging technology, can pave the way for application of novel clinical approaches. Identification of pathology-specific biomarkers and their application to diagnosis and treatment, support the individualized treatment algorithms.