Effect of verteporfin photodynamic therapy on endostatin and angiogenesis in human choroidal neovascular membranes

Histone deacetylase inhibitor attenuates experimental fungal keratitis in mice

Fungal keratitis is one of the leading causes of blindness of infected corneal diseases, but the pathogenesis of fungal keratitis is not fully understood and therefore the treatment of the disease by medication is still under investigation. In the current study, we sought to study the effect of HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) on experimental fungal keratitis in mice. SAHA (25 mg/kg) (n = 30) or vehicle (DMSO) (n = 30) was delivered through intraperitoneal injection (IP) 24 hours after the fungal inoculation, and the same amount of SAHA injection or DMSO was followed at day 2. The expression of histone H3 (H3), acetylated histone H3 (AC-H3), histone deacetylase 1 (HDAC)1, tumor necrosis factor-α (TNFα), and Toll-like receptor 4 (TLR4) in surgically excised specimens from the patients and mice with fungal keratitis were detected by immunohistochemistry. The expression of mRNAs for Interleukin-1β (IL-1β), TNFα, and TLR4 were evaluated in the corneas of the mice with fungal infection and the control corneas by real-time PCR. The quantification of IL-1β and TNFα in the corneas of the mice with fungal infection was determined by ELISA. The inhibitory effect of SAHA on mice fungal keratitis was revealed by GMS and H&E staining. We found that the downregulation of histone acetylation and upregulation of HDAC1 expression were associated with the increased inflammation response in fungal keratitis not only in humans but also in experimental animals. SAHA was able to inhibit experimental fungal keratitis in mouse by suppressing TLR4 and inflammatory cytokines such as TNFα and IL-1β; the inhibition of HDAC may be a potential therapeutic approach for the treatment of fungal keratitis.

Prognostic factors for combined ranibizumab and prompt verteporfin photodynamic therapy for polypoidal choroidal vasculopathy

PURPOSE

To investigate the prognostic factors for the combined therapy of ranibizumab and prompt verteporfin photodynamic therapy (vPDT) for eyes with polypoidal choroidal vasculopathy (PCV).

METHODS

Sixty-two PCV eyes of 62 patients that received the initial treatment of intravitreal ranibizumab followed by vPDT within 1 week plus a 2nd intravitreal ranibizumab 1 month later in one single medical center were retrospectively enrolled. Best-corrected visual acuity (BCVA) and parameters obtained from optical coherence tomography at baseline, 3 months, 6 months and 1  year were measured and compared. Factors associated with polyp regression, recurrent hemorrhage and visual improvement were analyzed.

RESULTS

After the loading treatment, complete and partial polyp regression was achieved in 53.6% and 39.3% of cases, respectively at Month 3. The mean logarithm of the minimum angle of resolution of BCVA improved from 0.64 ± 0.38 to 0.55 ± 0.46 (P =  0.008) at Month 12. Recurrent hemorrhage (P =  0.001) and previous anti-vascular endothelial growth factor (VEGF) treatment (P =  0.017) were associated with poorer visual improvement at Month 12. Incomplete polyp regression (P =  0.038) and previous anti-VEGF treatment (P =  0.005) were associated with a higher risk of recurrent hemorrhage.

CONCLUSIONS

Recurrent hemorrhage was associated with poor visual improvement after combined ranibizumab and vPDT for PCV. Complete polyp eradication was associated with a lower risk of recurrent hemorrhage. Patients who had previously received anti-VEGF were associated with recurrent hemorrhage and poor visual improvement; more frequent follow-ups and more aggressive subsequent treatments may be needed for these cases.

Polypoidal choroidal vasculopathy: An update on current management and review of literature

Polypoidal choroidal vasculopathy (PCV) is a subtype of neovascular age-related macular degeneration (nAMD), commonly seen in the Asian population. It is dissimilar in epidemiology, genetic heterogeneity, pathogenesis, natural history, and response to treatment in comparison to nAMD. Confocal scanning laser ophthalmoscopy-based simultaneous fluorescein angiography and indocyanine green angiography, spectral-domain optical coherence tomography (OCT) with enhanced depth imaging, swept-source OCT, and OCT angiography have improved the ability to detect PCV, understand its pathology, and monitor treatment response. A plethora of literature has discussed the efficacy of photodynamic therapy, anti-vascular endothelial growth factor (VEGF) monotherapy, and combination of both, but only a few studies with higher level of evidence and limited follow-up duration are available. This review discusses the understanding of PCV with respect to epidemiology, pathogenesis, clinical features, natural history, imaging techniques, and various treatment options. Recent clinical trials (EVEREST-II and PLANET study) have emphasized that either anti-VEGF monotherapy or combination treatment is equally capable to strike a balance between polyp regression and stabilization of visual acuity. The recurrent nature of the disease, the development of macular atrophy, and the long-term poor visual prognosis despite treatment are concerns that open avenues for further research.

The Efficiency of Verteporfin as a Therapeutic Option in Pre-Clinical Models of Melanoma

Yes Associated Protein 1 (YAP) and Transcriptional coactivator with PDZ-Binding Motif (TAZ) have gained notoriety for their ability to drive tumor initiation and progression in a wide variety of cancers, including melanoma. YAP and TAZ act as drivers of melanoma through its interaction with the TEAD family of transcription factors. Verteporfin is a benzoporphyrin derivative that is used clinically for photodynamic treatment of macular degeneration. Recently it has emerged as a potential inhibitor of YAP/TAZ-TEAD interaction independent of light activation. In this study we determine if verteporfin has clinical potential by testing this compound on human melanoma cell cultures and in a clinically significant mouse model, Braf^CA; Tyr-CreERT2; Pten^f/f, which parallels human melanoma in terms of disease progression, genetics, and histopathology. In culture, Verteporfin treatment induces a rapid drop in YAP and TAZ protein levels and cell numbers. In the transgenic model, utilizing drug levels that correspond to previously determined safe doses in human patients and with a dosing regimen calculated in this study, Verteporfin did not inhibit melanoma initiation or progression in comparison to mock treated controls. Taken together, our study suggests that although Verteporfin induces YAP/TAZ degradation in melanoma cell lines, Verteporfin was not effective as a YAP/TAZ-TEAD specific inhibitor of melanoma in our studies that aimed to mimic conditions found in clinic in terms of treatment regimen and disease model.

Co-Administered Polymeric Nano-Antidotes for Improved Photo-Triggered Response in Glioblastoma

Polymer-based nanoparticles (NPs) are useful vehicles in treating glioblastoma because of their favorable characteristics such as small size and ability to cross the blood–brain barrier, as well as reduced immunogenicity and side effects. The use of a photosensitizer drug such as Verteporfin (BPD), in combination with a pan-vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitor (TKI), Cediranib (CED), encapsulated in NPs will provide the medical field with new research on the possible ways to treat glioblastoma. Concomitant administration of BPD and CED NPs have the potential to induce dual photocytotoxic and cytostatic effects in U87 MG cells by (1) remotely triggering BPD through photodynamic therapy by irradiating laser at 690 nm and subsequent production of reactive oxygen species and (2) inhibiting cell proliferation by VEGFR interference and growth factor signaling mechanisms which may allow for longer progression free survival in patients and fewer systemic side effects. The specific aims of this research were to synthesize, characterize and assess cell viability and drug interactions for polyethylene-glycolated (PEGylated) polymeric based CED and BPD NPs which were less than 100 nm in size for enhanced permeation and retention effects. Synergistic effects were found using the co-administered therapies compared to the individual drugs. The major goal of this research was to investigate a new combination of photodynamic-chemotherapy drugs in nano-formulation for increased efficacy in glioblastoma treatment at reduced concentrations of therapeutics for enhanced drug delivery in vitro.

Choroidal morphology and short-term outcomes of combination photodynamic therapy in polypoidal choroidal vasculopathy

PURPOSE

To investigate outcomes of combined photodynamic therapy (PDT) and intravitreal bevacizumab in association with choroidal morphology in polypoidal choroidal vasculopathy (PCV).

METHOD

Eighty-six PCV eyes (83 patients) treated with PDT in combination with intravitreal bevacizumab and followed for 1 year were evaluated. Choroidal morphological features including subfoveal choroidal thicknesses, diameter of pachyvessel, and choroidal vascularity were analyzed for association with responsiveness and recurrence.

RESULT

Total choroid, Haller's layer, and pachyvessel were thicker in responders (n = 70) compared with non-responders (n = 16) at baseline (298 vs. 227 μm, 213 vs. 144 μm, and 276 vs. 210 μm, respectively; all P ≤ 0.001). Choroidal vascularity was significantly higher (0.68 vs 0.60, P < 0.001) and choroidal hyperpermeability was more frequent in responders (44 vs 13%, P = 0.018). Significant thinning of total choroid was observed in both responders and non-responders at 3 months after combination PDT (both P < 0.05), but the reduction was greater in responders (- 33 μm vs. - 10 μm, P = 0.036). In recurrent eyes (n = 26), increase in pachyvessel diameter and choroidal vascularity was observed at recurrence.

CONCLUSION

Choroidal morphology including characteristic features of pachychoroid and high vascularity can serve as predictive factors for outcomes after combination PDT in eyes with PCV.

Incidence, outcomes, and risk factors for hemorrhagic complications in eyes with polypoidal choroidal vasculopathy following photodynamic therapy in Indian subjects

PURPOSE

To evaluate the incidence, outcomes, and risk factors for hemorrhagic complications in eyes with polypoidal choroidal vasculopathy (PCV) following photodynamic therapy (PDT).

METHODS

Medical records of 94 eyes of 86 consecutive patients with PCV who underwent PDT between January 2007 and December 2014 were retrospectively reviewed. The diagnosis of PCV was based on clinical features and indocyanine green angiography. Eyes were treated with PDT monotherapy or a combination of PDT plus anti-vascular endothelial growth factor. PDT was performed at (standard [SFPDT] or reduced fluence RFPDT).

RESULTS

Ninety-four eyes had 119 PDT treatment sessions (mean: 1.3 sessions). Mean presenting vision was 0.46 ± 0.44 logarithm of the minimum angle of resolution (logMAR). Following PDT, ten eyes (11%) of nine patients had hemorrhagic complications such as subretinal hemorrhage (SRH; n = 5), subretinal pigment epithelium (RPE) hemorrhage (n = 1), breakthrough vitreous hemorrhage (BVH; n = 3), and SRH with sub-RPE hemorrhage and BVH (n = 1). Median interval to hemorrhage following PDT was 2 months. Age (P = 0.842), duration of symptoms (P = 0.352), number of laser spots (P = 0.219), and laser spot size (LSS) (P = 0.096) were not significantly associated with increased risk of hemorrhagic complications. Female gender was associated with reduced risk of hemorrhage (P = 0.045). SFPDT was significantly associated with increased risk of hemorrhage (P = 0.026). The probability of developing hemorrhagic complications in SFPDT group was 0.24 compared to 0.07 in RFPDT group (P = 0.039). Multivariate logistic regression analysis showed SFPDT as the only significant risk factor for hemorrhage following PDT (odds ratio 5.3, 95% confidence interval 1.1-24.8, P = 0.03). Mean final vision was 0.61 ± 0.53 logMAR at mean follow-up of 33 months (median = 22 months; range = 2-157 months).

CONCLUSION

Age, LSS, number of laser spots, preexisting hemorrhages, or use of anticoagulants were not associated with increased risk of hemorrhagic complications. SFPDT was significantly associated with increased risk of hemorrhagic complications in such eyes.

Polypoidal Choroidal Vasculopathy

PURPOSE OF REVIEW

The goal of this paper is to review the recent literature of polypoidal choroidal vasculopathy (PCV) and provide an update on the epidemiology, pathophysiology, clinical findings, and management.

RECENT FINDINGS

Although indocyanine-green angiography (ICGA) is still the gold standard for diagnosis of PCV, the use of en face optical coherence tomography (OCT) and OCT angiography are useful tools in the diagnosis of PCV. Studies demonstrate superior treatment outcomes with combination photodynamic therapy (PDT) and anti-vascular endothelial growth factor (VEGF) therapy.

SUMMARY

PCV is a disease most commonly in Asians and African-Americans and presents with an orange-red nodule in the macula or the peripapillary region. While ICGA remains the most accurate method to diagnose PCV, newer non-invasive imaging modalities (eg. OCT-A and en face OCT) can be used to identify PCV lesions. The combination of PDT and anti-VEGF therapy is superior to either monotherapy. Future studies of OCT modalities and other anti-VEGF agents will be important in guiding PCV diagnosis and management, respectively.

Age-related macular degeneration and polypoidal choroidal vasculopathy in Asians

Age-related macular degeneration (AMD) is the leading cause of irreversible blindness in elderly people globally. It is estimated that there will be more Asians with AMD than the rest of the world combined by 2050. In Asian populations, polypoidal choroidal vasculopathy (PCV) is a common subtype of exudative AMD, while choroidal neovascularization secondary to AMD (CNV-AMD) is the typical subtype in Western populations. The two subtypes share many common clinical features and risk factors, but also have different epidemiological and clinical characteristics, natural history and treatment outcomes that point to distinct pathophysiological processes. Recent research in the fields of genetics, proteomics and imaging has provided further clarification of differences between PCV and CNV-AMD. Importantly, these differences have manifested as disparity in response to intravitreal injections of anti-vascular endothelial growth factor (anti-VEGF) treatment between PCV and CNV-AMD, emphasizing the need for accurate diagnosis of PCV and in distinguishing PCV from CNV-AMD, particularly in Asian patients. Current clinical trials of intravitreal anti-VEGF therapy and photodynamic therapy will provide clearer perspectives of evidence-based management of PCV and may lead to paradigm shifts in therapeutic strategies away from those currently employed in the treatment of CNV-AMD. Further research is needed to clarify the relative contribution of specific pathways in inflammation, complement activation, extracellular matrix dysregulation, lipid metabolism and angiogenesis to the pathogenesis of PCV. Findings from this research, together with improved diagnostic technology and new therapeutics, will facilitate more optimal management of Asian AMD.

Polypoidal Choroidal Vasculopathy in Asians

Age related macular degeneration (AMD) in Asians has been suggested to differ from their Western counterparts in terms of epidemiology, pathogenesis, clinical presentation and treatment. In particular, polypoidal choroidal vasculopathy (PCV) appears to be the predominant subtype of exudative AMD in Asian populations, in contrast to choroidal neovascularization secondary to AMD (CNV-AMD) in Western populations. Epidemiological data on PCV has been largely limited to hospital-based studies and there are currently no data on the incidence of PCV. Similarities and differences in risk factor profile between PCV and CNV-AMD point to some shared pathogenic mechanisms but also differential underlying mechanisms leading to the development of each phenotype. Serum biomarkers such as CRP, homocysteine and matrix metalloproteinases suggest underlying inflammation, atherosclerosis and deranged extracellular matrix metabolism as possible pathogenic mechanisms. In addition, recent advances in genome sequencing have revealed differences in genetic determinants of each subtype. While the standard of care for CNV-AMD is anti-vascular endothelial growth factor (VEGF) therapy, photodynamic therapy (PDT) has been the mainstay of treatment for PCV, although long-term visual prognosis remains unsatisfactory. The optimal treatment for PCV requires further clarification, particularly with different types of anti-VEGF agents and possible benefits of reduced fluence PDT.

Photodynamic therapy versus combination therapy in polypoidal choroidal vasculopathy: changes of aqueous vascular endothelial growth factor

PURPOSE

To investigate the influence of photodynamic therapy (PDT) and combination of PDT and ranibizumab on aqueous humor levels of vascular endothelial growth factor (VEGF) in polypoidal choroidal vasculopathy (PCV).

DESIGN

Prospective randomized clinical trial.

METHOD

We included 20 eyes with treatment-naïve PCV and 20 eyes undergoing cataract surgery as controls. PCV eyes were randomized to treatment with PDT alone or to a combination of ranibizumab and PDT on the same day. During 3 months, retreatment was not performed. Aqueous humors were collected at baseline and at 1 week, 1 month, and 3 months after treatment in the PCV group and during cataract surgery in the control group. VEGF levels were measured using multiplex bead immunoassay.

RESULTS

At baseline, VEGF levels were significantly increased in PCV eyes compared with control eyes. A significant decrease in VEGF levels was found at 1 week after PDT treatment (n = 8) and at all time points after combination treatment (n = 12). With combination treatment, VEGF levels were decreased to values below the detection limit in all eyes at 1 week and 1 month and in 7 of 12 eyes at 3 months. There was no difference in the clinical profiles among the 2 treatment groups at each time point.

CONCLUSION

Decreased levels of VEGF detected 1 week after PDT for PCV seems to reflect acute damage of vascular endothelial cells, one of the VEGF expression sites in PCV. Concomitant ranibizumab resulted in a further decrease in VEGF to negligible levels, but this result did not affect the clinical results for 3 months.

Progression of macular atrophy after PDT combined with the COX-2 inhibitor Nabumetone in the treatment of neovascular ARMD

AIM

To evaluate photodynamic therapy (PDT) combined with the preferential the cyclooxygenase-2 (COX-2) inhibitor, nabumetone in the treatment of the neovascular age-related macular degeneration (ARMD).

METHODS

A prospective, double-blind, randomized study on 60 patients with subfoveal CNV secondary to ARMD without any previous treatment. Patients were divided into a nabumetone or placebo group. The main endpoints were the change of best-corrected visual acuity (BCVA), central macular thickness (CRT) and number of required PDT treatments.

RESULTS

In the nabumetone group, 27 patients (90%) and 28 (93%) in the placebo group completed the follow-up of 12 months. In the nabumetone group, the mean CRT decreased from 332 μm (SD 68 μm) to 220 μm (SD 46 μm). In the placebo group, CRT decreased from 331 μm (SD 72 μm) to 254 μm (SD 61 μm). The mean BCVA was 0.68 log MAR (SD 0.22 log MAR) in the nabumetone group and 0.62 log MAR (SD 0.23 log MAR) in the placebo group at baseline. This stabilised in the placebo group to 0.66 log MAR (SD 0.33) but deteriorated in the nabumetone group to 0.86 log MAR (SD 0.41 log MAR). There was a significant reduction in the number of required PDTs in the nabumetone group, but significant progression of the RPE atrophy area.

CONCLUSION

Combined PDT with oral intake of the COX-2 inhibitor, nabumetone reduced the number of required PDT retreatments, but worsening BCVA caused by macular atrophy progression. Therefore the combination of the PDT with the nabumetone is not recommended.

Intravitreal ranibizumab with or without photodynamic therapy for the treatment of symptomatic polypoidal choroidal vasculopathy

PURPOSE

To evaluate the efficacy of intravitreal ranibizumab with or without verteporfin photodynamic therapy (PDT) in the treatment of symptomatic polypoidal choroidal vasculopathy.

METHODS

Twenty-three eyes of 23 patients received 3 monthly intravitreal ranibizumab injections with or without indocyanine green angiography-guided PDT at baseline. All patients had follow-up of ≥12 months. Visual and anatomical outcomes were compared between the two groups and a PDT monotherapy group.

RESULTS

Seven eyes had ranibizumab monotherapy, 16 had combined ranibizumab injections and verteporfin PDT, and 12 had PDT monotherapy. At 3 months, the mean logarithm of minimal angle of resolution best-corrected visual acuity improved from 0.92 to 0.74 in the ranibizumab group (P = 0.18), from 0.70 to 0.59 in the combined group (P = 0.037), and from 0.74 to 0.57 in the PDT monotherapy group (P = 0.014). Complete regression of polypoidal lesions in indocyanine green angiography was found in 1 (14.3%) eye in the ranibizumab group, compared with 15 (93.8%) eyes in the combined group (P = 0.001). Additional PDT and ranibizumab injections in eyes with persistent polyps and fluorescein leakage resulted in regression of polyps in all eyes. At 12 months, no significant difference in logarithm of minimal angle of resolution best-corrected visual acuity and visual change was found between eyes initially treated with ranibizumab monotherapy, combined ranibizumab and PDT, or PDT monotherapy (P = 1.00 and P = 0.11, respectively).

CONCLUSION

Intravitreal ranibizumab appeared to result in stabilization of vision in patients with symptomatic polypoidal choroidal vasculopathy. However, combined ranibizumab and PDT appeared to be more effective in causing complete regression of the polypoidal lesions in indocyanine green angiography compared with ranibizumab monotherapy.

Aqueous humor levels of vascular endothelial growth factor before and after intravitreal bevacizumab in type 3 versus type 1 and 2 neovascularization. A prospective, case-control study

PURPOSE

To determine the aqueous levels of vascular endothelial growth factor (VEGF) in patients with type 3 neovascularization (NV) secondary to age-related macular degeneration (AMD) and to compare the levels of those with type 1 and 2 NV secondary to AMD before and after administration of intravitreal bevacizumab (IVB).

DESIGN

Prospective, case-control study.

METHODS

Aqueous samples were collected from 29 eyes of 29 patients with untreated wet AMD at baseline (day of the first IVB), month 1 (day of the second IVB), and month 2 (day of the third IVB). Among them, 10 eyes presented with type 1, 9 with type 2, and 10 with type 3 NV. A group of 14 aqueous samples from 14 patients who underwent cataract surgery without other ocular or systemic disease comprised the controls. Main outcome measures were concentration of VEGF at baseline and after IVB in the 3 NV groups; secondary outcome measures included best-corrected visual acuity (BCVA) and central macular thickness (CMT) changes after IVB. Levels of VEGF were determined by commercially available enzyme-linked immunosorbent assay kits.

RESULTS

VEGF concentrations in aqueous humor at baseline were higher in patients with type 3 NV when compared to controls (P = .0001) and type 1 and 2 NV patients (P = .002 and P = .0001 respectively). At month 1, levels of VEGF were significantly reduced compared to baseline (P < .05) and significantly lower compared to the controls (P < .005) in each NV group. These low levels were maintained at the 2-month interval. BCVA significantly improved in type 1 and 2 NV groups (P < .05). CMT significantly reduced in each NV group compared to baseline (P < .05).

CONCLUSION

In eyes with untreated wet AMD, aqueous levels of VEGF are significantly higher in type 3 NV than in type 1 or 2 NV. Regardless of the type of NV, aqueous VEGF levels significantly reduce 1 month after IVB as compared to both the baseline measurements and the values recorded in age-matched controls. These decreases are maintained at 2 months after administering a second IVB 30 days after the initial injection.

Photodynamic therapy with or without intravitreal triamcinolone acetonide for symptomatic polypoidal choroidal vasculopathy

PURPOSE

To evaluate the outcome of verteporfin photodynamic therapy (PDT) with or without intravitreal triamcinolone acetonide (IVTA) for the treatment of symptomatic polypoidal choroidal vasculopathy (PCV).

METHODS

Retrospective analysis of PCV patients who underwent PDT with or without IVTA with follow-up of 2 or more years. Changes in best-corrected visual acuity (BCVA), proportion of eyes with moderate visual loss (3 or more lines), and complications were compared between patients with or without IVTA.

RESULTS

Twenty-seven eyes of 27 patients were analyzed, with 12 eyes treated by PDT monotherapy and 15 eyes treated by combined PDT with IVTA. The baseline characteristics of both groups were similar. At 1 year, the mean logMAR BCVA for the PDT monotherapy group improved from 0.74 to 0.58 (P = 0.011), whereas the combined PDT and IVTA group improved from 0.84 to 0.74 (P = 0.17). At 2 years, the mean logMAR BCVA for the monotherapy and combined treatment groups were 0.62 and 0.84, respectively, and the changes compared with baseline were not statistically significant. No significant difference was found in the mean logMAR BCVA, the mean line of visual changes, and the mean number of PDT treatments between the 2 groups at 1 and 2 years. One (8.3%) and 4 (26.7%) eyes in the monotherapy and the combined groups lost 3 or more lines at 2 years, respectively. Patients who had combined PDT with IVTA were more likely to develop cataract requiring surgery and ocular hypertension (P = 0.043 and 0.046, respectively).

CONCLUSIONS

PDT reduced the risks of visual loss in patients with symptomatic PCV in the short term but the effect might not be sustained after 1 year. The adjunctive use of IVTA during PDT did not appear to result in additional benefit for treating PCV.

The protective role of Visudyne eyeglass against VEGF synthesis after photodynamic therapy with verteporfin

PURPOSE

We aimed to determine the extent of protection provided by Visudyne eyeglass against vascular endothelial growth factor (VEGF) synthesis following photodynamic therapy (PDT).

METHODS

Three groups with 14 rabbits in each were established. These consisted of a control (dextrose infusion) group, an infusion (verteporfin infusion) group and an irradiation (verteporfin infusion + irradiation) group. One eye in each animal was closed with Visudyne eyeglass and the other by eyelid sutures. The rabbits were exposed to daylight for 30 mins at 2 and 48 hours after the infusion was administered. Half the animals in each group were killed on day 5. The remaining animals were killed on day 10. Levels of VEGF in homogenized retina and choroids were analysed with an ELISA (enzyme-linked immunosorbent assay).

RESULTS

Mean VEGF levels, in pg/mg protein, on days 5 and 10 in the control + glass, control + suture, infusion + glass, infusion + suture, irradiation + glass and irradiation + suture subgroups were, respectively: 1.69 +/- 0.67, 1.91 +/- 0.44; 1.75 +/- 0.69, 1.93 +/- 0.53; 2.30 +/- 0.77, 3.47 +/- 2.02; 1.90 +/- 1.00, 2.93 +/- 0.16; 4.39 +/- 2.74, 13.63 +/- 5.25; 3.38 +/- 1.05, 7.37 +/- 2.12. On day 10, VEGF levels were significantly higher in the infusion and irradiation groups compared with the control group (p < 0.05). There were no statistically significant differences between glass and suture samples on days 5 and 10 in the infusion group, or on day 5 in the irradiation group. However, on day 10, the mean VEGF level in eyes closed with Visudyne eyeglass in the irradiation group was significantly higher than in sutured eyes (p = 0.011).

CONCLUSIONS

Visudyne eyeglass offers full protection against VEGF increases caused by verteporfin infusion but is only partially protective in eyes exposed to sensitizing light.

Implications of bevacizumab on vascular endothelial growth factor and endostatin in human choroidal neovascularisation

AIM

To evaluate the implications of intravitreal bevacizumab on proangiogenic vascular endothelial growth factor (VEGF) with regard to the endogenous angiogenesis inhibitor endostatin in human choroidal neovascularisation (CNV) secondary to age-related macular degeneration.

METHODS

Retrospective review of an interventional case series of 48 patients who underwent full macular translocation surgery with removal of CNV. Twenty-five patients were treated with intravitreal bevacizumab injection 1 to 154 days prior to surgery (bevacizumab CNV). Twenty-three CNV without any kind of previous treatment were used as controls (control CNV). CNV were stained for CD34, cytokeratin18, VEGF, endostatin and E-selectin. A "predominance score of VEGF over endostatin" (PS) was defined by the difference between VEGF and endostatin staining scores.

RESULTS

Bevacizumab CNV revealed a weaker VEGF expression in endothelial cells (p = 0.0245) but significantly more intense endostatin in retina pigment epithelium (RPE) (p = 0.0001) and stroma (p<0.0001). Consequently, PS was significantly lower in RPE (p = 0.02), vessels (p = 0.03) and stroma (p = 0.0004) in bevacizumab CNV. The intensity of E-selectin expression in bevacizumab CNV was comparable with that in control CNV.

CONCLUSIONS

A shift within the angiogenic balance in terms of decreased VEGF predominance over endostatin is detected in human CNV treated with bevacizumab.

The role of vascular endothelial growth factor and other endogenous interplayers in age-related macular degeneration

Age-related macular degeneration (AMD) is a multifaceted disease characterized by early subclinical changes at the choroidea-retinal pigment epithelium interface. Both the causal and formal pathogenesis of the disease is still puzzling. Similarly, the reason for progression into two distinct late forms which are "geographic atrophy" and "choroidal neovascularization" remains enigmatic. Late changes are usually responsible for the dramatic loss in central function that has a devastating effect on quality of life. In industrialized countries the disease is a major cause for visual disability among persons over 60 years of age. Due to demographic right-shift and increased life expectancy, AMD is not only a medical problem but will have a pronounced socio-economic effect. Neovascular AMD with the development of choroidal neovascularization in the macular area accounts for 80% of the severe loss of visual acuity due to AMD. In the last decades, treatment modes were merely based on the destruction or surgical removal of the neovascular complex. In the present, however, the philosophical approach to treat the disease is changing to a pathology modifying manner. Intelligent targeting of the involved relevant factors and pathways should stop disease progression, reduce complications and improve vision. The first step into this new era has been accomplished with the introduction of antiangiogenic agents. The new agents act either directly on vascular endothelial growth factor (VEGF) or indirectly on its functional cascade. VEGF makes a fundamental contribution to neovascular processes but it also acts in physiological pathways. The main purpose of this review is to summarize its physiological role especially within the eye, the role in the development of AMD and to understand and foresee both the benefits and potential side-effects of the anti-VEGF-based therapy.

Matrix metalloproteinases in human choroidal neovascular membranes excised following verteporfin photodynamic therapy

AIM

To evaluate expression of proangiogenic matrix metalloproteinases (MMP) 2 and 9 at distinct intervals after verteporfin photodynamic therapy (PDT) in human choroidal neovascular membranes (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Retrospective review of an interventional case series of 49 patients who underwent removal of CNV. Twenty-six patients were treated with PDT 3 to 383 days prior to surgery. Twenty-three CNV without previous treatment were used as controls. CNV were stained for CD34, cytokeratin 18, endostatin, MMP-2 and MMP-9 by immunohistochemistry.

RESULTS

CNV without previous therapy disclosed MMP-2, MMP-9 in RPE-Bruch's membrane, vessels and stroma in different intensities. Three days after PDT, MMP-9 expression was significantly weaker in stroma (p = 0.0019). Endostatin was significantly reduced in vessels (p<0.001). At longer post-PDT intervals, a significant increase of MMP-9 in stroma (p = 0.037) and of endostatin in RPE-Bruch's membrane (p = 0.02), vessels (p = 0.005) and stroma (p<0.001) were disclosed. No significant changes in MMP-2 expression were detected.

CONCLUSIONS

PDT induced an early, temporary decrease in MMP-9 and endostatin expression. At longer intervals, MMP-9 increase is possibly associated with the angiogenic process responsible for recurrence after PDT. MMP-9, however, acts as a double-edged sword by concomitant induction of endostatin, an endogenous inhibitor of angiogenesis.