Zhenyu Dong

Elevated choroidal blood flow velocity during systemic corticosteroid therapy in Vogt-Koyanagi-Harada disease

Purpose:  Laser speckle flowgraphy (LSFG) can be used to non‐invasively visualize the haemodynamics of choroidal circulation and the vascular pattern. The purpose of this study was to examine the ability of LSFG to quantitatively evaluate blood flow velocity at the macula in patients with Vogt–Koyanagi–Harada (VKH) disease before and after systemic corticosteroid therapy.

Alphab-crystallin expression in epiretinal membrane of human proliferative diabetic retinopathy.

Purpose: To examine the expression of alphaB-crystallin and its colocalization with vascular endothelial growth factor in the epiretinal membrane of human proliferative diabetic retinopathy. Methods: Ten epiretinal membranes of proliferative diabetic retinopathy and three normal retinas surgically excised were included in this study. Paraformaldehyde-fixed, paraffin-embedded tissue sections were processed for immunohistochemistry with alphaB-crystallin, vascular endothelial growth factor, and CD31 antibodies. Results: AlphaB-crystallin was expressed in all epiretinal membranes examined. The immunolocalization of alphaB-crystallin was detected in the cytoplasm of CD31-positive endothelial cells, but not in normal retinal blood vessels. Furthermore, alphaB-crystallin immunoreactivity was colocalized in vascular endothelial growth factor–positive endothelial cells in proliferative diabetic retinopathy membranes. Conclusion: AlphaB-crystallin was expressed in proliferative diabetic retinopathy membranes, and colocalized with vascular endothelial growth factor–positive neovessels. AlphaB-crystallin may play a potential role in the pathogenesis of epiretinal membranes in proliferative diabetic retinopathy, together with vascular endothelial growth factor.

Expression of vascular endothelial growth factor and intravitreal anti-VEGF therapy with bevacizumab in vasoproliferative retinal tumors.

Purpose: To examine whether vasoproliferative retinal tumors (VPRTs) express vascular endothelial growth factor and respond to intravitreal bevacizumab injection. Methods: Retrospective interventional case series. Intravitreal bevacizumab 1.25 mg was administered to 9 patients with VPRT-associated neovascularization or exudative retinal changes. The changes of the tumor size, best-corrected visual acuity, and central retinal thickness were evaluated before and after treatment. Immunohistochemistry with anti–vascular endothelial growth factor antibody in an excised tissue of VPRT during pars plana vitrectomy was performed. Results: In two patients with small tumors (within two disk diameters), the tumors disappeared or regressed with only one injection of intravitreal bevacizumab injection. Larger tumors regressed after additional laser photocoagulation and/or cryotherapy without recurrence of exudative retinal changes in six eyes, although these did not regress by intravitreal bevacizumab injection alone. The mean logarithm of the minimal angle of resolution value of best-corrected visual acuity and central retinal thickness at the final visit were significantly improved compared with those of pretreatment (P = 0.02 and P = 0.03, respectively). Immunoreactivity for vascular endothelial growth factor was strongly detected in the resected tumor tissue. Conclusion: These results suggest that vascular endothelial growth factor derived from VPRTs causes retinal neovascularization or exudative retinal changes associated with VPRTs. Intravitreal bevacizumab may be a useful therapeutic option for these complications secondary to VPRTs.

Efficacy and complications of intravitreal injection of triamcinolone acetonide for refractory cystoid macular edema associated with intraocular inflammation

PurposeTo assess the effects and complications of intravitreal injection of triamcinolone acetonide (IVTA) for posterior sub-Tenon injection of triamcinolone acetonide (PSTA)-resistant cystoid macular edema (CME) with intraocular inflammation.MethodsMedical records of eight eyes of six patients with PSTA-resistant CME were retrospectively examined. Each eye received a 4-mg IVTA, and an additional injection was performed when CME recurred. Visual acuity as logarithm of the minimum angle of resolution (logMAR), intraocular pressure (IOP), and central macular thickness (CMT) were assessed before and after each treatment.ResultsCME improved in six eyes (75%) with mean visual acuity recovering from 0.56 ± 0.29 to 0.41 ± 0.195 (logMAR, P = 0.13) and mean CMT decreasing from 470 μm (range, 275–660 μm) to 297 μm (range, 150–697 μm) (P = 0.04) 2 months after the initial IVTA. CME recurred an average of 9 months (range, 5–11 months) after IVTA. A higher dose (16-mg) IVTA was effective for two eyes refractory to repeated 4-mg IVTA. IOP was elevated in two eyes (25%), of which one required filtration surgery (12.5%). In phakic eyes, cataracts progressed and necessitated surgery.ConclusionsIVTA is effective for PSTA-resistant CME with intraocular inflammation, and its efficacy might be dose dependent.

Clinical and histological evaluation of large macular hole surgery using the inverted internal limiting membrane flap technique

Purpose The aims of this study were to analyze optical coherence tomography (OCT) imaging of large macular holes (MHs) treated with inverted internal limiting membrane (ILM) flap technique and to perform a histological examination of an ILM-like membrane tissue obtained during vitrectomy. Patients and methods This is a retrospective observational case study. Nine patients, comprising of five males and four females, showing large and myopic MHs, underwent pars plana vitrectomy (PPV) with inverted ILM flap technique assisted by brilliant blue G (BBG) staining. Ophthalmological findings including visual acuity and OCT were investigated based on medical records. Formalin-fixed paraffin-embedded tissue section of an ILM-like membrane was submitted for immunohistochemistry with glial fibrillary acidic protein (GFAP). Results ILM was clearly stained with BBG in eight patients, whereas the ILM in one case revealed no staining with BBG during PPV. Visual acuities improved to >0.2 LogMAR in six patients. The complete closure of MH following PPV with inverted ILM technique was eventually achieved in all patients determined by OCT imaging (100%). Only one patient showed recovery of ellipsoid zone and interdigitation zone following the surgery. Elongation of outer nuclear layer was noted in three eyes. The ILM-like membrane not stained with BBG histologically revealed an amorphous structure admixed with GFAP-positive mononuclear cell infiltration. Conclusion PPV with inverted ILM flap technique achieved 100% closure rates with favorable configuration at an initial surgery in large MHs. Our histopathological data also suggest that even BBG staining-negative membrane may be a useful material for autologous transplantation to the hole.

Tissue Kallikrein Attenuates Choroidal Neovascularization via Cleavage of Vascular Endothelial Growth Factor

PURPOSE To investigate the antiangiogenic properties of tissue kallikrein in a murine model of laser-induced choroidal neovascularization (CNV). METHODS CNV was induced in male C57BL/6J mice by laser photocoagulation. The animals received daily subcutaneous injections of tissue kallikrein (50 μg/kg) or vehicle control for 2 days before the laser photocoagulation, and this treatment continued until sample collection. Seven days after laser injury, the CNV size was quantified. The levels of monocyte chemoattractant protein (MCP)-1, intercellular adhesion molecule (ICAM)-1, and interleukin (IL)-6 were assessed by enzyme-linked immunosorbent assay 3 days after laser injury. Cleavage of mouse VEGF with tissue kallikrein was assessed in vivo and in vitro. The protein levels of bradykinin were assessed in the RPE-choroid complexes and hearts. RESULTS A significant decrease in CNV size was observed in animals treated with tissue kallikrein (27,168.3 ± 2432.2 μm(2)) compared with vehicle-treated controls (36,374.6 ± 3204.1 μm(2), P < 0.05). Tissue kallikrein treatment significantly reduced MCP-1, ICAM-1, and IL-6 levels in RPE-choroid complexes. Furthermore, immunoblotting showed the bands, presumably corresponding to the fragmented VEGF(164) protein, in the samples of both mouse VEGF preincubated with tissue kallikrein and RPE-choroid complexes obtained from animals treated with tissue kallikrein. In addition, bradykinin was unchanged in the RPE-choroid complexes of animals treated with tissue kallikrein, whereas the level of bradykinin was increased in the heart obtained from these experimental animals. CONCLUSIONS The current data indicate that kallikrein exhibits antiangiogenic properties by cleaving VEGF(164) in a laser-induced CNV model.

Amelioration of experimental autoimmune uveoretinitis by inhibition of glyceraldehyde‐derived advanced glycation end‐product formation

AGEs are permanently modified macromolecule derivatives that form through nonenzymatic glycation of amino groups of proteins. Glycer‐AGEs are highly toxic and play an important role in the pathogenesis of chronic inflammatory diseases. However, the contribution of glycer‐AGEs to the pathogenesis of uveitis is unclear. In this study, we measured serum levels of glycer‐AGEs in 100 patients with endogenous uveitis (22 with HLA‐B27‐associated uveitis, 20 with VKH disease, 14 with Behçets disease, and 44 with sarcoidosis) and 33 healthy volunteers. We then examined the effect of the AGE inhibitor in a mouse model of human endogenous uveitis (EAU) by continuous oral administration of pyridoxamine at 200 or 400 mg/kg/day. Regardless of the etiology, serum glycer‐AGE levels were significantly higher in patients with uveitis than in healthy subjects. Treatment with 400 mg/kg pyridoxamine significantly reduced the clinical and histological severity of EAU and was accompanied by a significant decrease in serum and retinal glycer‐AGE levels and suppression of translocation of NF‐κB p65 into the nucleus of retinal cells. Serum glycer‐AGE levels may therefore serve as a biomarker of human uveitis, as well as systemic inflammation, and may contribute to the progression of uveitis, including diabetic iritis, via the activation of NF‐κB.

Immunolocalization of Vascular Adhesion Protein-1 in Human Conjunctival Tumors

Objective: We analyzed the expression and immunolocalization of vascular adhesion protein (VAP)-1 in conjunctival tumors and normal conjunctival tissue of humans. Methods: Nine conjunctival tumors, including pyogenic granuloma and extranodal marginal zone B-cell lymphoma (EMZL), and 2 normal conjunctivas were analyzed by immunohistochemistry for VAP-1 and CD31 expression. Results: Immunoreactivity for VAP-1 was detected in the lumen of microvessels in pyogenic granuloma and in EMZLs. In contrast, normal bulbar conjunctival tissues demonstrated weak cytoplasmic immunoreactivity for VAP-1 in the blood vessels. Conclusions: The immunolocalization of VAP-1 varied in the histopathology of the conjunctiva, involving the pathology of inflammatory conjunctival disorders.

Effect of geranylgeranylacetone on the protection of retinal ganglion cells in a mouse model of normal tension glaucoma

Glaucoma is characterized by axonal degeneration of retinal ganglion cells (RGCs) and apoptotic death of their cell bodies, and lowering intraocular pressure is associated with an attenuation of progressive optic nerve damage. Nevertheless, intraocular pressure (IOP) reduction alone was not enough to inhibit the progression of disease, which suggests the contribution of other factors to the glaucoma pathogenesis. In this study, we investigated the cytoprotective effect of geranylgeranylacetone (GGA) on RGCs degeneration using a normal tension glaucoma (NTG) mouse model, which lacks glutamate/aspartate transporter (GLAST) and demonstrates spontaneous RGC and optic nerve degeneration without elevated intraocular pressure (IOP). Three-week-old GLAST+/− mice were given oral administration of GGA at 100, 300, or 600 mg/kg/day or vehicle alone, and littermate control mice were given vehicle alone for 14 days, respectively. At 5 weeks after birth, the number of RGCs was counted in paraffin sections of retinal tissues stained with hematoxylin and eosin. In addition, retrograde labeling technique was also used to quantify the number of RGC. Expression and localization of heat shock protein 70 (HSP70) in retinas were evaluated by reverse transcription polymerase chain reaction and immunohistochemistry, respectively. Activities of caspase-9 and -3 in retinas were also assessed. The number of RGCs of GLAST+/− mice significantly decreased, as compared to that of control mice. RGC loss was significantly suppressed by administration of GGA at 600 mg/kg/day, compared with vehicle alone. Following GGA administration, HSP70 was significantly upregulated together with reduction in the activities of caspase-9 and -3. Our studies highlight HSP70 induction in the retina is available to suppress RGC degeneration, and thus GGA may be applicable for NTG as a promising therapy.

Expression of Vascular Endothelial Growth Factor in Human Ocular Adnexal Lymphoma

PURPOSE To examine the expression of VEGF in extranodal marginal zone B-cell lymphoma (EMZL) and reactive lymphoid hyperplasia (RLH) of human ocular adnexa, and analyze the correlation with the intratumoral microvessel density (MVD). METHODS Twenty-two EMZL and 16 RLH tissues were examined in this study. Paraformaldehyde-fixed, paraffin-embedded tissue sections were processed for immunohistochemistry with antibodies against VEGF and CD20. Vascular endothelial growth factor expression was analyzed using the ELISA and RT-PCR in the EMZL tissues. Microvessel density was determined based on the immunoreactivity for anti-CD34 antibody. RESULTS Vascular endothelial growth factor immunoreactivity was detected in the cytoplasm of lymphoid cells in EMZL and RLH. ELISA and RT-PCR confirmed VEGF protein and mRNA expressions in the EMZL tissue, respectively. Vascular endothelial growth factor-immunopositive rate in B-cells was significantly higher in 12 conjunctival EMZLs than four RLHs (P < 0.01) and 10 orbital EMZLs than 12 RLHs (P < 0.05). The MVD showed a significant positive correlation with the VEGF-immunopositive rate in conjunctival and orbital EMZLs. CONCLUSIONS This study demonstrated increased VEGF expression in human conjunctival and orbital EMZL compared with that in RLH, suggesting that VEGF plays a significant role in the pathogenesis and tumor angiogenesis of ocular adnexal lymphoma.