EFFECTIVENESS OF EN BLOC REMOVAL OF FIBRINOGEN-RICH COMPONENT OF CYSTOID LESION FOR THE TREATMENT OF CYSTOID MACULAR EDEMA

Potential Mechanism of Platelet GPIIb/IIIa and Fibrinogen on Retinal Vein Occlusion

PURPOSE

To explore the role of coagulation and fibrinolytic factors, and the potential mechanism of platelet aggregation in the pathogenesis of retinal vein occlusion.

METHODS

Coagulation and fibrinolytic parameters in patients with retinal vein occlusion were determined using hemagglutinin and HISCL-5000. Relationships between these elevated parameters and factors representing typical clinical manifestations of retinal vein occlusion were examined, and these parameters were analyzed using a STRING database to indicate the potential role of platelet aggregation. Platelet glycoprotein IIb/IIIa (GPIIb/IIIa) levels were evaluated by flow cytometry after antiplatelet treatment in patients and mouse models. Furthermore, the GPIIb/IIIa ligand fibrinogen in peripheral blood and retina of mouse models was assessed by the turbidimetric method and real-time PCR, respectively.

RESULTS

In patients, significant increases in peripheral blood fibrinogen and GPIIb/IIIa levels were observed (p = 0.0040, p < 0.0001, respectively). A positive correlation was observed between macular thickness (MT) and both fibrinogen and GPIIb/IIIa (r = 0.4528, p = 0.0063; r = 0.3789, p = 0.0427, respectively). After intravitreal injections of anti-vascular endothelial growth factor drugs, a significant reduction in fibrinogen levels was observed (p = 0.0072). In addition, the use of antiplatelet drugs resulted in a significant decrease in GPIIb/IIIa (p < 0.0001). In a mouse model, antiplatelet therapy significantly reduced both peripheral blood and retina fibrinogen levels and the overall rate of vein occlusion 3 days after occlusion (p < 0.0005). In addition, the reduction in GPIIb/IIIa levels after antiplatelet therapy was remarkable.

CONCLUSION

Fibrinogen and GPIIb/IIIa may be involved in retinal vein occlusion and blocking platelet aggregation may be a new therapeutic approach for retinal vein occlusion.

Clinicopathological findings in refractory diabetic macular edema: A case report

The present study describes the case of a patient with refractory diabetic cystoid macular edema who underwent vitrectomy with en bloc removal of the cystoid lesion component. The current study also performed histopathological and immunohistochemical analyses of the cystoid lesion component to assess fibrin/fibrinogen and advanced glycation end-products (AGEs) immunoreactivity. A 69-year-old Japanese man presented with visual loss in the left eye due to residual cystoid macular edema (CME) refractory to anti-vascular endothelial growth factor therapy. Best-corrected visual acuity was 1.2 in the right eye (OD) and 0.5 in the left eye (OS). Fundus examination showed dot hemorrhages and hard exudates in the peri-macular region with pan-retinal photocoagulation scars in both eye. Swept-source optical coherence tomography revealed CME with slight hyperreflectivity in the cyst OS. A total of 3 months after the initial visit, pars plana vitrectomy was performed, and the translucent solidified component within the cystoid lesion was isolated. Histopathologically, the excised component was elliptical in shape, measuring 0.7x0.4 mm and exhibited homogeneous eosinophilic material without cellular components. No membranous structure was observed surrounding the component. Immunohistochemistry demonstrated that the tissue was positive for fibrin/fibrinogen and weakly positive for AGEs, but was negative for glial fibrillary acidic protein, type 1 collagen and receptor for AGEs. To the best of our knowledge, the present case report is the first to histopathologically examine the contents of refractory CME, and to immunohistochemically demonstrate that fibrin in diabetic CME may be post-translationally modified by AGEs. These results suggested that fibrin in CME may escape degradation by plasmin due to post-translational modifications.

Current Treatments for Diabetic Macular Edema

Diabetic retinopathy is a major retinal disorder and a leading cause of blindness. Diabetic macular edema (DME) is an ocular complication in patients with diabetes, and it can impair vision significantly. DME is a disorder of the neurovascular system, and it causes obstructions of the retinal capillaries, damage of the blood vessels, and hyperpermeability due to the expression and action of vascular endothelial growth factor (VEGF). These changes result in hemorrhages and leakages of the serous components of blood that result in failures of the neurovascular units (NVUs). Persistent edema of the retina around the macula causes damage to the neural cells that constitute the NVUs resulting in diabetic neuropathy of the retina and a reduction in vision quality. The macular edema and NVU disorders can be monitored by optical coherence tomography (OCT). Neuronal cell death and axonal degeneration are irreversible, and their development can result in permanent visual loss. Treating the edema before these changes are detected in the OCT images is necessary for neuroprotection and maintenance of good vision. This review describes the effective treatments for the macular edema that are therefore neuroprotective.

THE LONG-TERM EFFECT OF CYSTOTOMY WITH FIBRINOGEN CLOT REMOVAL FOR A CYSTOID MACULAR EDEMA SECONDARY TO IDIOPATHIC MACULAR TELANGIECTASIA TYPE 1: A CASE REPORT

PURPOSE

To report the case of a patient with cystoid macular edema secondary to idiopathic macular telangiectasia (MacTel) Type 1, which was successfully treated by cystotomy and en bloc removal of the fibrinogen-rich component of the cystoid lesion.

METHODS

An 80-year-old man was referred to our department because of a visual defect in his right eye. His best-corrected decimal visual acuity was 0.7 (Snellen equivalent, 20/30). A fundus examination revealed clustered temporal juxafoveal microaneurysms and foveal cystoid macular edema. The patient refused to undergo conventional treatments, including direct retinal photocoagulation for microaneurysms, intravitreal anti-vascular endothelial growth factor injection, and intravitreal triamcinolone injection. However, he provided consent to undergo cystotomy and en bloc removal of the fibrinogen-rich component of the cystoid lesion.

RESULTS

His best-corrected decimal visual acuity was 0.2 (Snellen equivalent, 20/100) just before the surgery. A 27-gauge vitrectomy with internal limiting membrane peeling was performed. Cystotomy was performed during the surgery, and the fibrinogen clot visible in the cystoid cavity was also removed. Cystoid macular edema rapidly disappeared after the surgery. Three years postoperatively, the patient had best-corrected decimal visual acuity of 0.5 (Snellen equivalent, 20/40) at the last medical examination, and the cystoid macular edema had not recurred.

CONCLUSION

Cystotomy and en bloc removal of the fibrinogen-rich component of the cystoid lesion could be valid treatment options for cystoid macular edema secondary to MacTel Type 1.

The Role of Intravitreal Corticosteroids in the Treatment of DME: Predictive OCT Biomarkers

This work aims to summarize predictive biomarkers to guide treatment choice in DME. Intravitreal anti-VEGF is considered the gold standard treatment for centers involving DME, while intravitreal steroid treatment has been established as a second-line treatment in DME. However, more than 1/3 of the patients do not adequately respond to anti-VEGF treatment despite up to 4-weekly injections. Not surprisingly, insufficient response to anti-VEGF therapy has been linked to low-normal VEGF levels in the serum and aqueous humor. These patients may well benefit from an early switch to intravitreal steroid treatment. In these patients, morphological biomarkers visible in OCT may predict treatment response and guide treatment decisions. Namely, the presence of a large amount of retinal and choroidal hyperreflective foci, disruption of the outer retinal layers and other signs of chronicity such as intraretinal cysts extending into the outer retina and a lower choroidal vascular index are all signs suggestive of a favorable treatment response of steroids compared to anti-VEGF. This paper summarizes predictive biomarkers in DME in order to assist individual treatment decisions in DME. These markers will help to identify DME patients who may benefit from primary dexamethasone treatment or an early switch.

Intravitreal Tissue Plasminogen Activator Injection for Treatment-Resistant Diabetic Macular Edema of the Vitrectomized Eye

Diabetic macular edema (DME) is the main cause of visual loss in patients with diabetic retinopathy. DME has been treated using intravitreal anti-vascular endothelial growth factor (VEGF) drugs, steroids, laser photocoagulation, vitreoretinal surgery, and their combinations. These modalities are generally effective in preserving vision, but they sometimes produce only limited responses in patients with persistent or refractory DME. The levels of various inflammatory factors, including cytokines, chemokines, and extracellular matrices, as well as VEGF in the vitreous fluid, are increased in patients with DME. Excessive fibrinogen/fibrin levels in the vitreous fluid or fibrin deposition in the retina also contribute to DME pathogenesis. Tissue plasminogen activator (t-PA) promotes the degradation of fibrinogen or fibrin. Intravitreal t-PA injection is a commonly used treatment for subretinal hemorrhage secondary to age-related macular degeneration. Intravitreal t-PA injections have previously been used to restore vision by inducing posterior vitreous detachment in patients with DME. Herein, we describe the visual outcomes of intravitreal t-PA injection in a 78-year-old woman with treatment-resistant DME in her vitrectomized eye after several previous treatments. Before the injection, her best-corrected visual acuity (BCVA) was 0.7 logMAR and central foveal retinal thickness (CRT) was 735 μm. At 1 month after the injection, her BCVA was 0.8 logMAR and CRT was 558 μm, and 3 months later, her BCVA was 0.8 logMAR and CRT was 207 μm. Her BCVA was sustained, and CRT showed gradual improvements. These findings suggested the effectiveness of intravitreal t-PA injections for DME in the vitrectomized eye.

Increased expression of Protein S in eyes with diabetic retinopathy and diabetic macular edema

Protein S (PS) is a multifunctional glycoprotein that ameliorates the detrimental effects of diabetes mellitus (DM). The aim of this study was to evaluate the distribution of PS in diabetic retinopathy (DR) and diabetic macular edema (DME). This was a study of 50 eyes with DM (37 with DME, 6 with proliferative DR, and 7 with no DR) and 19 eyes without DM. The level of PS was measured by enzyme immunoassay and was compared between eyes with or without DM, with or without DME, and with severe DME (≥ 350 μm) or mild DME (< 350 μm). We also performed immunohistopathologic evaluations of post-mortem eyes and the cystoid lesions excised during surgery. The aqueous free PS was significantly higher with DM (7.9 ± 1.2 ng/ml, P < 0.01) than without DM (6.1 ± 0.7). The aqueous free PS was significantly elevated with DME (8.2 ± 1.2, P < 0.05) compared to proliferative DR (7.0 ± 1.0) and no DR (7.0 ± 0.7). Eyes with severe DME had significantly higher aqueous free PS than mild DME (8.5 ± 1.3 vs. 7.7 ± 1.0, P < 0.05). Immunohistochemistry showed PS in the outer plexiform layer of the retina and cystoid lesion. The higher expression of PS with DR and DME suggests that PS is involved in their pathogenesis.

Cystotomy with or without fibrinogen clot removal for refractory cystoid macular edema secondary to branch retinal vein occlusion

To demonstrate the long-term effect of cystotomy with or without fibrinogen clot removal for treatment-resistant cystoid macular edema (CME) secondary to branch retinal vein occlusion (BRVO). Retrospective clinical study. We retrospectively analyzed medical records of 22 eyes of 22 patients with treatment-resistant CME secondary to BRVO with 12 months observation after cystotomy with or without fibrinogen clot removal. Patients included 11 women and 11 men. The mean ± SD age was 72.7 ± 10.2 years. LogMAR-converted best corrected visual acuity (BCVA) was statistically better at 12 months after surgery (0.30 ± 0.30) than preoperative BCVA (0.39 ± 0.27) (p = 0.01). The central sensitivity of microperimetry (dB) was maintained during follow-up (preoperative sensitivity: 25.4 ± 4.1, postoperative sensitivity at 12 months after the surgery: 25.9 ± 4.2, p = 0.69). Twelve months after surgery, there was a significant improvement in the central retinal thickness (CRT) on optical coherence tomography (OCT) (303.7 ± 80.1) (μm) compared with the preoperative CRT (524.2 ± 114.8) (p < 0.01). In 12 months, CME recurred in 3 of 22 eyes. The preoperative reflectivity in cystoid cavity on OCT was significantly higher in patients with fibrinogen clot removal (n = 5) than in patients without fibrinogen clot removal (n = 17) (p < 0.01). For treatment-resistant CME secondary to BRVO, Cystotomy with or without fibrinogen clot removal may be one of the treatment options.

LONG-TERM EFFECT OF CYSTOTOMY WITH OR WITHOUT THE FIBRINOGEN CLOT REMOVAL FOR REFRACTORY CYSTOID MACULAR EDEMA SECONDARY TO DIABETIC RETINOPATHY

PURPOSE

To show the long-term effect of cystotomy with or without fibrinogen clot removal for refractory cystoid macular edema secondary to diabetic retinopathy.

METHODS

Retrospective analyses of the medical records of 30 eyes of 30 patients with refractory cystoid macular edema secondary to diabetic retinopathy who had followed up for 12 months after the surgery were performed.

RESULTS

There were 15 men and 15 women. The mean ± SD age was 68.4 ± 7.9 years. The best-corrected visual acuity (logarithm of the minimal angle of resolution) at 12 months after the surgery (0.33 ± 0.25, Snellen equivalent, 20/42) was statistically better than the preoperative best-corrected visual acuity (0.45 ± 0.33, Snellen equivalent, 20/56) (P < 0.01). The central sensitivity on microperimetry (dB) was not statistically changed between preoperatively (24.0 ± 4.9) and 12 months after the surgery (24.1 ± 4.0) (P = 0.75). The central retinal thickness on optical coherence tomography (μm) at 12 months after the surgery (300.3 ± 99.0) was statistically improved compared with the preoperative central retinal thickness (565.6 ± 198.7) (P < 0.01). During the follow-up period, cystoid macular edema relapsed in seven of 30 eyes. The preoperative cystoid cavity reflectivity on optical coherence tomography in patients with fibrinogen clot removal (n = 16) was significantly higher than that in patients without fibrinogen clot removal (n = 14) (P < 0.04).

CONCLUSION

The cystotomy with or without fibrinogen clot removal may be a promising treatment option for refractory cystoid macular edema secondary to diabetic retinopathy.

Surgical outcomes of vitrectomy for intractable diabetic macular edema

PURPOSE

To investigate clinical outcomes of vitrectomy for intractable diabetic macular edema (DME) in which anti-vascular endothelial growth factor (anti-VEGF) agents or periocular steroid were not effective.

METHODS

This retrospective study examined 27 eyes of 25 cases. The main measurements included changes in visual acuity (VA) and retinal morphology. Vitrectomies were performed using the Constellation System 25G.

RESULTS

Prior to undergoing vitrectomy, patients were treated with anti-VEGF agents or periocular injection of triamcinolone acetonide. The average number of anti-VEGF agent injections was 3.1 ± 2.8. Triamcinolone was used in 15 eyes. There was no significant change in the mean logMAR best-corrected visual acuity (BCVA) between baseline and posttreatment, with values of 0.49 ± 0.29 and 0.55 ± 0.33, respectively (P = 0.31). Compared with preoperative BCVA, postoperative BCVA improved by more than two lines in 4 eyes (14%), remained the same in 17 eyes (63%), and decreased in 6 eyes (23%). Morphologically, retinal thickness improved by more than 50 μm in 16 eyes (59%), remained unchanged in 7 eyes (26%), and increased in 5 eyes (18%). Retinal edema resolved in all of the cases in which macular epiretinal membrane (ERM) or vitreomacular traction (VMT) was detected by optical coherence tomography during pretreatment.

CONCLUSIONS

Vitrectomy can potentially stabilize the retinal morphology in intractable DME and is likely more effective in DME cases accompanied by ERM or VMT.