Increased expression of periostin and tenascin-C in eyes with neovascular glaucoma secondary to PDR.

PURPOSE: To investigate periostin (PN) and tenascin-C (TNC) expression in the aqueous humor and trabeculectomy specimens of patients with neovascular glaucoma (NVG) secondary to proliferative diabetic retinopathy (PDR). METHODS: This study enrolled 37 eyes of 37 patients who were grouped into (1) NVG secondary to PDR (NVG; n = 8); (2) PDR without NVG (PDR; n = 9); (3) primary open-angle glaucoma (POAG; n = 11); and (4) cataract surgery patients as a control group (CG; n = 9). Aqueous humor samples were collected from the anterior chamber at the start of surgery or intravitreal injection of anti-VEGF drug. The concentrations of PN, TNC, VEGF, and TGF-ß2 (transforming growth factor-beta 2) were measured by ELISA. Sclerostomy tissues containing trabecular meshwork were obtained from two NVG patients and a POAG patient who underwent trabeculectomy surgery. Immunohistochemical analyses were performed to determine the localization of PN and TNC expression in the sclerostomy tissues. RESULTS: PN and TNC-C levels were below detection threshold in the POAG and CG groups. The NVG group had significantly higher levels of PN and TNC compared with the PDR group (84.7 ng/ml vs 2.2 ng/ml and 18.5 ng/ml vs 4.6 ng/ml, respectively; p < 0.05). There was a significant correlation between the levels of PN and TNC-C in the NVG group (r = 0.86, p < 0.05). We found significant expression of PN in the trabecular meshwork and Schlemm's canal of sclerostomy tissues excised from patients with NVG. CONCLUSIONS: Increased PN and TNC expression suggests their possible involvement in the pathogenesis of NVG secondary to PDR.

Risk Factors and Preventive Effects of Laser Panretinal Photocoagulation for Neovascular Glaucoma after Ophthalmic Stereotactic Radiotherapy.

Purpose: To evaluate the risk factors and the preventive effects of laser panretinal photocoagulation (PRP) for neovascular glaucoma (NVG) after ophthalmic stereotactic radiotherapy. Methods: Twenty-four patients with ocular malignant tumor (such as uveal malignant melanoma, lacrimal gland cancer) who received stereotactic radiotherapy (such as gamma knife, cyber knife) were retrospectively analyzed. Patients were divided into group A without preventive PRP (n=9), and group B with preventive PRP (n=15). Survival curves were plotted using the Kaplan-Meier method and compared between the two groups with the log-rank test. Results: In group A, NVG occurred in 3 patients. In contrast, in group B, no patient encountered NVG. The significant risk factor for NVG was dose-volumes that irradiated the optic disk (p=0.045). The incidence of NVG was significantly reduced in group B compared with group A (p=0.019). Conclusions: Dose-volumes that irradiated the optic disk were risk factors for NVG. PRP is effective in the prevention of NVG.

[Ocular surface squamous neoplasia: analysis of 34 cases].

PURPOSE: To evaluate location, treatment and clinical course in cases of ocular surface squamous neoplasia (OSSN). METHODS: Thirty-four cases with OSSN [conjunctival intraepithelial neoplasia (CIN) 17 cases; squamous cell carcinoma (SCC) 17 cases] treated in Kyushu University hospital from 2000 to 2011 were retrospectively studied. RESULT: Lesions of CIN were observed in the conjunctiva bulbar in sixteen cases (16/17), and in eleven of those, the lesions were seen in the nasal part (nasal : lateral = 11 : 6). The lesions of eight SCC cases (8/17) were observed in the conjunctiva bulbar, of seven cases (7/17) were observed in the conjunctiva palpebral, and of two cases (2/17) in the fornical conjunctiva. Significantly far more cases of SCC in the conjunctiva bulbar were seen in the nasal part compared to the lateral part (nasal : lateral = 7 : 1). Most SCC lesions in the conjunctiva palpebral and fornix were observed in the upper eyelid (upper : lower = 6 : 3). CIN were treated by excision in nine cases (9/17), excision after topical chemotherapy in three cases (3/ 17), and topical chemotherapy in 5 cases (5/17). Nine SCC patients were treated by excision (9/17), four by excision after topical chemotherapy (4/17), and four by radiotherapy (4/17). Three cases of CIN and one case of SCC had recurrence and needed further treatment. CONCLUSION: The use of preoperative chemotherapy and radiotherapy for OSSN patients seems useful for a good outcome.

Discontinuous LYVE-1 expression in corneal limbal lymphatics: dual function as microvalves and immunological hot spots.

LYVE-1(+) corneal lymphatics contribute to drainage and immunity. LYVE-1 is widely accepted as the most reliable lymphatic marker because of its continuous expression in lymphatic endothelium. LYVE-1 expression in corneal lymphatics has not been examined. In this study, we report intact CD31(+) corneal lymphatic capillary endothelial cells that do not express LYVE-1. The number of LYVE-1(-) gaps initially increased until 8 wk of age but was significantly reduced in aged mice. C57BL/6 mice showed a notably higher number of the LYVE-1(-)/CD31(+) lymphatic regions than BALB/c mice, which suggests a genetic predisposition for this histological feature. The LYVE-1(-) lymphatic gaps expressed podoplanin and VE-cadherin but not αSMA or FOXC2. Interestingly, the number of LYVE-1(-) gaps in FGF-2, but not VEGF-A, implanted corneas was significantly lower than in untreated corneas. Over 70% of the CD45(+) leukocytes were found in the proximity of the LYVE-1(-) gaps. Using a novel in vivo imaging technique for visualization of leukocyte migration into and out of corneal stroma, we showed reentry of extravasated leukocytes from angiogenic vessels into newly grown corneal lymphatics. This process was inhibited by VE-cadherin blockade. To date, existence of lymphatic valves in cornea is unknown. Electron microscopy showed overlapping lymphatic endothelial ends, reminiscent of microvalves in corneal lymphatics. This work introduces a novel corneal endothelial lymphatic phenotype that lacks LYVE-1. LYVE-1(-) lymphatic endothelium could serve as microvalves, supporting unidirectional flow, as well as immunological hot spots that facilitate reentry of stromal macropahges.

Altered vascular microenvironment by bevacizumab in diabetic fibrovascular membrane.

PURPOSE: The purpose of this study was to evaluate the impact of intravitreal bevacizumab (IVB) on three cellular components (vascular endothelial cells, pericytes, and myofibroblasts) of the vascular microenvironment in fibrovascular membranes (FVMs) of patients with proliferative diabetic retinopathy. METHODS: Immunohistological studies with antibodies of CD34, αSMA, and transforming growth factor-ß were performed on 20 surgical specimens obtained during a pars plana vitrectomy from 8 IVB-treated eyes, whereas 12 remained untreated. Four different indexes of vascular phenotype (vascular area, vascular major axis, CD34 endothelial area, and blood vessel density) and αSMA expression in vascular and stromal components were quantitatively analyzed. RESULTS: The intraluminal area of blood vessels, CD34 endothelial area, and the blood vessel density in IVB-treated FVMs were significantly less than in untreated FVMs. The number of CD34 blood vessels in IVB-treated FVMs was similar to that in untreated FVMs. Intravitreal bevacizumab could not affect vascular and stromal αSMA area significantly. However, the ratio of vascular αSMA area/CD34 area was significantly higher in IVB-treated FVMs than in untreated FVMs. Transforming growth factor-ß expression could be observed in the IVB-treated FVM. CONCLUSION: Intravitreal bevacizumab might primarily affect blood vessels, and the effects on pericytes and myofibroblasts might be secondary. Intravitreal bevacizumab treatment regulates vascular microenvironment by the contraction of blood vessels, the increasing pericyte ratio, and transforming growth factor-ß expression in FVMs of patients with proliferative diabetic retinopathy.

Optical coherence tomography angiography of choroidal neovascularization in immune choroiditis following acute retinal necrosis.

PURPOSE: To report optical coherence tomography angiography (OCTA) findings in a case of immune choroiditis following contralateral acute retinal necrosis (ARN) with choroidal neovascularization (CNV) during anti-vascular endothelial growth factor (VEGF) therapy. CASE REPORT: A 64-year-old woman with immune choroiditis following contralateral ARN and secondary CNV presented with decreased visual acuity. Fundus examination revealed macular and peripheral yellowish lesions in the right eye. Inflammatory cells were observed in the anterior chamber and the vitreous. OCT revealed retinal exudative changes and subretinal lesions suggestive of CNV. OCTA detected an abnormal vascular net in the outer retina as well as choriocapillaris, corresponding to type 2 CNV, that reduced following intravitreous anti-VEGF therapy. Two weeks after treatment, OCTA showed re-dilated choroidal neovasculature at the outer retina despite no exudative recurrence in OCT. Six weeks after treatment, OCT detected exudative changes around the neovascular lesion. CONCLUSION: This case discusses the use of OCTA detection of CNV in a case of immune choroiditis following contralateral ARN. During anti-VEGF therapy for inflammatory CNV-related diseases, OCTA may be useful not only for CNV detection but also for the follow-up of CNV activity.

Drainage Retinotomy Confers Risk of Epiretinal Membrane Formation After Vitrectomy for Rhegmatogenous Retinal Detachment Repair.

PURPOSE: To describe the factors associated with epiretinal membrane (ERM) formation in eyes treated with pars plana vitrectomy (PPV) for rhegmatogenous retinal detachment (RRD). DESIGN: Nationwide, multicenter, clinical cohort study based on registry data. METHODS: We reviewed 2239 cases treated with PPV for RRD repair registered in the Japan-Retinal Detachment Registry between February 2016 and March 2017. Associations of 13 baseline characteristics and 8 surgical procedures with ERM formation were evaluated using univariate analysis. We conducted a propensity score-matched analysis for the significantly associated clinical factor(s). The primary outcome measure was ERM formation after 6 months of vitrectomy. RESULTS: ERM had developed in 104 cases (4.6%) by 6 months. We found that drainage retinotomy was significantly associated with ERM after multiple testing correction (odds ratio [OR] 2.22 [95% confidence interval {CI} 1.50-3.31]; P < .001). In the propensity score-matched analysis (n = 492 in each group), we confirmed a significant difference in the incidence of ERM after 6 months of vitrectomy (8.3% and 2.6% in cases with and without drainage retinotomy, respectively; OR 3.35 [95% CI 1.77-6.33]; P < .001). CONCLUSIONS: Eyes treated with PPV combined with drainage retinotomy are more likely to develop ERM postoperatively.

Postoperative follow-up of submacular hemorrhage displacement treated with vitrectomy and subretinal injection of tissue plasminogen activator: ultrawide-field fundus autofluorescence imaging in gas-filled eyes.

PURPOSE: To investigate the utility of Optos ultrawide-field fundus autofluorescence (UWF-FAF) imaging for postoperative follow-up of gas-filled eyes after vitrectomy with subretinal tissue-plasminogen activator (t-PA) injection for subretinal hemorrhage (SRH) displacement. STUDY DESIGN: Retrospective consecutive case series. METHODS: This study included 24 eyes with SRH. Vitrectomy with subretinal t-PA injection was performed, followed by postoperative prone positioning. FAF images acquired using Optos California were examined and the SRH occupancy in the macula was calculated. The main outcome measures were displacement rate and direction of SRH for 3 days postoperatively, and postoperative best-corrected visual acuity (BCVA). RESULTS: The postoperative BCVA ranged from improvement (23 eyes; 95.8%) to no change (one eye; 4.2%). Analysis was done using postoperative Optos FAF images for 20 eyes (83.3%). Postoperative SRH occupancy was significantly reduced, by 27.4%, compared with the preoperative occupancy (P = 0.03). A statistically significant reduction was found between the preoperative and postoperative day (POD)1 (P = 0.04), but not between POD1 and POD2 (P = 0.7), or between POD2 and POD3 (P = 1.0). CONCLUSION: UWF-FAF imaging is useful for postoperative follow-up of gas-filled eyes after vitrectomy with subretinal t-PA injection for SRH displacement.

A Case of Bullous Central Serous Chorioretinopathy Treated with Surgical Removal of Submacular Fibrin and Subsequent Photodynamic Therapy under Silicone Oil.

Bullous retinal detachment is a rare complication in the chronic phase of central serous chorioretinopathy (CSC). Only a small subset of eyes with chronic CSC develops into the bullous variant of CSC (bCSC). In patients with bCSC, the elevated concentration of fibrin in the subretinal space leads to persistent retinal detachment and eventually, severe vision loss. We experienced a case of unilateral bCSC with a massive accumulation of subretinal fibrin. Multiple leakage points and dilated choroidal veins were also observed. The patient underwent surgical removal of subretinal fibrin and silicone oil injection followed by photodynamic therapy (PDT). After this treatment, the retina was successfully reattached, and the affected eye was free from recurrent exudative changes for more than 18 months. Massive subretinal fibrin could be surgically removed to prevent the formation of subretinal fibrosis and retinal fold, and PDT under silicone oil can control the underlying exudative changes in bCSC.

Intravitreal bevacizumab treatment for neovascular glaucoma: histopathological analysis of trabeculectomy specimens.

BACKGROUND: Neovascular glaucoma (NVG) is a serious complication for patients with proliferative diabetic retinopathy (PDR). Bevacizumab is a full-length humanized monoclonal antibody that binds all isoforms of vascular endothelial growth factor (VEGF). Recently, encouraging results regarding the off-label use of intravitreal bevacizumab (IVB) for the treatment of NVG have been reported. We evaluated the histology of bevacizumab-treated trabeculectomy specimens to clarify IVB's biological effects on angle neovascularization. METHODS: We retrospectively reviewed the charts of a consecutive series of 15 eyes of 13 patients who underwent trabeculectomy to treat NVG caused by PDR. In ten eyes of eight patients, 1.25 mg bevacizumab was injected intravitreally via the pars plana. Using light or electron microscopy, the surgically excised trabecular tissue was compared to that without IVB. RESULTS: Light microscopy revealed decreased edema, fibrin deposition, inflammation and vascular congestion in the trabecular meshwork in specimens with IVB compared to those without IVB. Electron microscopy revealed endothelial cell degeneration in the bevacizumab-treated specimens. CONCLUSIONS: The biological effects on angle neovascularization after IVB may involve reduced vascular permeability, decreased inflammatory reaction, loss of vascular function, and endothelial cell degeneration.

Spreds are essential for embryonic lymphangiogenesis by regulating vascular endothelial growth factor receptor 3 signaling.

Spred/Sprouty family proteins negatively regulate growth factor-induced ERK activation. Although the individual physiological roles of Spred-1 and Spred-2 have been investigated using gene-disrupted mice, the overlapping functions of Spred-1 and Spred-2 have not been clarified. Here, we demonstrate that the deletion of both Spred-1 and Spred-2 resulted in embryonic lethality at embryonic days 12.5 to 15.5 with marked subcutaneous hemorrhage, edema, and dilated lymphatic vessels filled with erythrocytes. This phenotype resembled that of Syk(-/-) and SLP-76(-/-) mice with defects in the separation of lymphatic vessels from blood vessels. The number of LYVE-1-positive lymphatic vessels and lymphatic endothelial cells increased markedly in Spred-1/2-deficient embryos compared with WT embryos, while the number of blood vessels was not different. Ex vivo colony assay revealed that Spred-1/2 suppressed lymphatic endothelial cell proliferation and/or differentiation. In cultured cells, the overexpression of Spred-1 or Spred-2 strongly suppressed vascular endothelial growth factor-C (VEGF-C)/VEGF receptor (VEGFR)-3-mediated ERK activation, while Spred-1/2-deficient cells were extremely sensitive to VEGFR-3 signaling. These data suggest that Spreds play an important role in lymphatic vessel development by negatively regulating VEGF-C/VEGFR-3 signaling.

Antiangiogenic mechanisms of simvastatin in retinal endothelial cells.

BACKGROUND: While statins have an anti-angiogenic property, their underlying mechanisms are not fully understood. We investigated intracellular mechanisms of simvastatin-mediated reduction in VEGF-induced signalings. METHODS: The effects of simvastatin on cell proliferation and viability were evaluated by [(3)H]-thymidine incorporation in retinal endothelial cells (RECs) and cell counting. The impact of simvastatin on VEGF-induced phosphorylation of p44/42 mitogen-activated protein (MAP) kinase, myosin light chain (MLC), and VEGF-receptor (VEGFR) 2 were examined by Western blotting. Involvement of the mevalonate pathway in VEGF-induced signaling was also examined. RESULTS: Simvastatin (1 and 10 microM) suppressed VEGF-induced RECs proliferation in a concentration-dependent manner, without affecting cell viability. Simvastatin significantly inhibited VEGF-induced phosphorylation of VEGFR2 and its downstream mediators, p44/42 MAP kinase and MLC. Mevalonate completely reversed VEGF-induced VEGFR2 phosphorylation, but only partially reversed the phosphorylation of p44/42 MAP kinase and MLC. CONCLUSION: These data indicate that simvastatin exerts its anti-angiogenic effects through the reduction of VEGFR2 phosphorylation in RECs at least in part. However, there seems to be both mevalonate-dependent and independent pathway in simvastatin's anti-angiogenic property.

Retinitis pigmentosa associated with asteroid hyalosis.

BACKGROUND: Asteroid hyalosis (AH) is a condition in which cream-colored or white spherical particles are suspended in the vitreous body. Asteroid hyalosis is considered not to cause decreased vision or any other visual symptoms except in rare cases. There have been a few reports of AH in patients with retinitis pigmentosa (RP). METHODS: To assess the prevalence of AH in patients with RP, 320 patients with typical forms of RP were studied. One patient was offered a standard three-port vitrectomy, and the spherical particles obtained from her vitrectomy sample were analyzed using an energy-dispersive x-ray spectrometer. RESULTS: Ten patients (two men and eight women) developed AH. Among them, four had bilateral AH and two had rapidly increasing vitreous opacity that led to decreased vision. One patient was a 48-year-old woman with progressive AH in the left eye. After treatment with a vitrectomy, her vision improved from 0.4 to 0.8. The spherical particles were composed of mainly calcium and phosphorus. CONCLUSION: The prevalence of AH in RP was higher than in previous reports, and we encountered two rare cases of progressive AH with decreased vision. We conclude that AH might lead to decreased vision in patients with RP.

VEGF-C regulates lymphangiogenesis and capillary stability by regulation of PDGF-B.

Emerging evidence indicates that the tight communication between vascular endothelial cells and mural cells using platelet-derived growth factor (PDGF)-BB is essential for capillary stabilization during the angiogenic process. However, little is known about the related regulator that determines PDGF-BB expression. Using murine models of therapeutic neovascularization, we here show that a typical lymphangiogenic factor, vascular endothelial growth factor (VEGF)-C, is an essential regulator determining PDGF-BB expression for vascular stabilization via a paracrine mode of action. The blockade of VEGF type 3 receptor (VEGFR3) using neutralizing antibody AFL-4 abrogated FGF-2-mediated limb salvage and blood flow recovery in severely ischemic hindlimb. Interestingly, inhibition of VEGFR3 activity not only diminished lymphangiogenesis, but induced marked dilatation of capillary vessels, showing mural cell dissociation. In these mice, VEGF-C and PDGF-B were upregulated in the later phase after induced ischemia, on day 7, when exogenous FGF-2 expression had already declined, and blockade of VEGFR3 or PDGF-BB activities diminished PDGF-B or VEGF-C expression, respectively. These results clearly indicate that VEGF-C is a critical mediator, not only for lymphangiogenesis, but also for capillary stabilization, the essential molecular mechanism of communication between endothelial cells and mural cells during neovascularization.

Inhibition of nuclear translocation of apoptosis-inducing factor is an essential mechanism of the neuroprotective activity of pigment epithelium-derived factor in a rat model of retinal degeneration.

Photoreceptor apoptosis is a critical process of retinal degeneration in retinitis pigmentosa (RP), a group of retinal degenerative diseases that result from rod and cone photoreceptor cell death and represent a major cause of adult blindness. We previously demonstrated the efficient prevention of photoreceptor apoptosis by intraocular gene transfer of pigment epithelium-derived factor (PEDF) in animal models of RP; however, the underlying mechanism of the neuroprotective activity of PEDF remains elusive. In this study, we show that an apoptosis-inducing factor (AIF)-related pathway is an essential target of PEDF-mediated neuroprotection. PEDF rescued serum starvation-induced apoptosis, which is mediated by AIF but not by caspases, of R28 cells derived from the rat retina by preventing translocation of AIF into the nucleus. Nuclear translocation of AIF was also observed in the apoptotic photoreceptors of Royal College of Surgeons rats, a well-known animal model of RP that carries a mutation of the Mertk gene. Lentivirus-mediated retinal gene transfer of PEDF prevented the nuclear translocation of AIF in vivo, resulting in the inhibition of the apoptotic loss of their photoreceptors in association with up-regulated Bcl-2 expression, which mediates the mitochondrial release of AIF. These findings clearly demonstrate that AIF is an essential executioner of photoreceptor apoptosis in inherited retinal degeneration and provide a therapeutic rationale for PEDF-mediated neuroprotective gene therapy for individuals with RP.

An early "reopening" case of idiopathic macular hole; supportive usefulness of fundus autofluorescence.

BACKGROUND: Anatomical closure of macular holes (MH) is now largely confirmed by optical coherence tomography (OCT). Fundus autofluorescence (FAF) is also helpful in diagnosis and anatomical estimation of MH. We report a case of early reopening of anatomically closed MH, 2 days after release from face-down positioning where FAF abnormalities proceeded OCT findings. METHODS: A case report. A 67-year-old woman underwent vitrectomy with brilliant blue G-assisted ILM peeling for the treatment of full-thickness stage 4 MH (diameter 578 microm). FAF and OCT were used to evaluate the patient. RESULTS: On post operative day 3, OCT showed anatomical closure of MH, but FAF persistently demonstrated hyperfluorescence in the fovea. On post operative day 5, 2 days after termination of positioning, OCT showed reopening of the MH. Intra-vitreous injection of 50 % sulfur hexafluoride (SF(6)) gas was performed followed by face-down positioning again. Fourteen days after surgery, we confirmed the findings of both the anatomical closure in OCT and hypofluorescence on FAF. Two months later, MH remained closed. CONCLUSIONS: FAF might be a useful measure as a supportive method to guide release from posture restriction.

Anatomical findings of vitreoretinal interface in eyes with asteroid hyalosis.

PURPOSE: To investigate the anatomical features of vitreoretinal interface in eyes with asteroid hyalosis (AH) with optical coherence tomography (OCT) and intravitreal triamcinolone acetonide (TA) during vitreous surgery. METHODS: This study was an interventional clinical case series. Records relating to ten eyes from ten patients who underwent a TA-assisted vitrectomy for the treatment of diverse vitreoretinal diseases complicated with AH. The posterior vitreoretinal interface was examined by preoperative OCT and by intraoperative visualization of posterior vitreous cortex utilizing TA. RESULTS: In eight of ten AH eyes, preoperative OCT revealed abnormal vitreoretinal adhesions. In four of these eight eyes, posterior vitreoschisis could be seen on OCT. In the other four of these eight eyes, a clear no posterior vitreous detachment (PVD) pattern could be seen on OCT. Although posterior vitreous cortex could not be clearly identified with preoperative OCT in two of ten AH eyes, a complete PVD was refuted by intraoperative visualization of the posterior vitreous cortex with TA identical to the other eight eyes. CONCLUSION: These results indicate that complete PVD appears to be unlikely to occur in eyes with AH. In addition, spontaneous PVD in eyes with AH might lead to vitreoschisis or residual whole layer or posterior vitreous cortex, possibly due to anomalous vitreoretinal adhesion.

Preoperative estimation of distance between retinal break and limbus with wide-field fundus imaging: Potential clinical utility for conventional scleral buckling.

OBJECTIVE: Accurate scleral marking of retinal breaks is essential for successful scleral buckling. This study aimed to investigate the use of wide-field fundus images obtained with an Optos for preoperative estimation of the distance from the limbus to the retinal breaks. METHODS AND ANALYSIS: This is a retrospective review of 29 eyes from 26 patients with rhegmatogenous retinal detachment who received scleral buckling with anatomically successful repair. They underwent wide-field fundus photography with Optos California. In the pre- and postoperative fundus images, we measured distances from the macula to the retinal tears (TM), to the center of the vortex veins (VM), to the optic disc (DM), and to the posterior edge of the scleral buckle (BM). RESULTS: (BM-VM) / DM was significantly correlated with the distance from the limbus to the posterior edge of the scleral buckle that had been determined intraoperatively. (r = 0.705; p<0.001) We applied a regression line derived from this correlation with the value of (TM -VM) / DM in order to calculate estimated distances between retinal breaks and the limbus. The calculated distances were all within the range of distances from the limbus to the anterior and posterior edges of the scleral buckles. CONCLUSION: Preoperative analysis of Optos images may be useful for estimating the distance from the limbus to retinal breaks, which might aid scleral marking during scleral buckling surgery.

Synergistic neuroprotective effect via simian lentiviral vector-mediated simultaneous gene transfer of human pigment epithelium-derived factor and human fibroblast growth factor-2 in rodent models of retinitis pigmentosa.

BACKGROUND: We previously demonstrated that a new lentiviral vector derived from nonpathogenic simian immunodeficiency virus (SIVagm) was efficient and safe for long-lasting retinal gene transfer, and that it provided the significant therapeutic effect of expressing human pigment epithelium-derived factor (hPEDF) in Royal College of Surgeons (RCS) rats. In the present study, to obtain a more pronounced outcome, we assessed the potential synergistic effect of the simultaneous gene transfer of hPEDF and human fibroblast growth factor-2 (hFGF-2) by improved third-generation SIV on RCS rats and retinal degeneration slow (rds) mice, because the former targets the primary neurons, including photoreceptor cells (PCs), whereas the latter is effective for targeting secondary neural cells, including Muller cells. METHODS: Vector solution (SIV-hPEDF, SIV-hFGF-2, a 1 : 1 mixture of SIV-hPEDF and SIV-hFGF-2, or SIV-enhanced green fluorescent protein) was injected into the peripheral subretinal space of 3-week-old RCS rats or rds mice. Histopathological and electroretinographic assessments were made at several points after gene transfer. RESULTS: Administration of SIV-hPEDF or SIV-hFGF-2 significantly delayed the histological PC degeneration and electrical deficit in RCS rats, and these delays were synergistically and significantly pronounced by SIV-hPEDF + SIV-hFGF-2 (1 : 1 mixture). In rds mice, functional therapeutic effects were observed even by SIV-PEDF, or SIV-FGF-2 alone and, moreover, both SIV-PEDF and SIV-FGF-2 showed higher therapeutic effects. CONCLUSIONS: These synergistic rescues of retinitis pigmentosa (RP) model animals are the 'proof concept' that the 'dual' expression of hPEDF and hFGF-2 dramatically improved therapeutic efficacy by keeping lower titers. This strategy may contribute to safer and more effective gene therapy for RP.

Diabetic microangiopathy in ischemic limb is a disease of disturbance of the platelet-derived growth factor-BB/protein kinase C axis but not of impaired expression of angiogenic factors.

Diabetic foot is caused by microangiopathy and is suggested to be a result of impaired angiogenesis. Using a severe hindlimb ischemia model of streptozotocin-induced diabetic mice (STZ-DM), we show that diabetic foot is a disease solely of the disturbance of platelet-derived growth factor B-chain homodimer (PDGF-BB) expression but not responses of angiogenic factors. STZ-DM mice frequently lost their hindlimbs after induced ischemia, whereas non-DM mice did not. Screening of angiogenesis-related factors revealed that only the expression of PDGF-BB was impaired in the STZ-DM mice on baseline, as well as over a time course after limb ischemia. Supplementation of the PDGF-B gene resulted in the prevention of autoamputation, and, furthermore, a protein kinase C (PKC) inhibitor restored the PDGF-BB expression and also resulted in complete rescue of the limbs of the STZ-DM mice. Inhibition of overproduction of advanced-glycation end product resulted in dephosphorylation of PKC-alpha and restored expression of PDGF-BB irrespective of blood sugar and HbA1c, indicating that advanced-glycation end product is an essential regulator for PKC/PDGF-BB in diabetic state. These findings are clear evidence indicating that diabetic vascular complications are caused by impairment of the PKC/PDGF-B axis, but not by the impaired expression of angiogenic factors, and possibly imply the molecular target of diabetic foot.