Clinicopathologic study after submacular removal of choroidal neovascular membranes treated with verteporfin ocular photodynamic therapy

Current Challenges and Opportunities of Photodynamic Therapy against Cancer

BACKGROUND

Photodynamic therapy (PDT) is an established, minimally invasive treatment for specific types of cancer. During PDT, reactive oxygen species (ROS) are generated that ultimately induce cell death and disruption of the tumor area. Moreover, PDT can result in damage to the tumor vasculature and induce the release and/or exposure of damage-associated molecular patterns (DAMPs) that may initiate an antitumor immune response. However, there are currently several challenges of PDT that limit its widespread application for certain indications in the clinic.

METHODS

A literature study was conducted to comprehensively discuss these challenges and to identify opportunities for improvement.

RESULTS

The most notable challenges of PDT and opportunities to improve them have been identified and discussed.

CONCLUSIONS

The recent efforts to improve the current challenges of PDT are promising, most notably those that focus on enhancing immune responses initiated by the treatment. The application of these improvements has the potential to enhance the antitumor efficacy of PDT, thereby broadening its potential application in the clinic.

Regenerative medicine as a novel strategy for AMD treatment: a review

Age-related macular degeneration (AMD) is known as a major cause of irreversible blindness in elderly adults. The segment of the retina responsible for central vision damages in the disease process. Degeneration of retinal pigmented epithelium (RPE) cells, photoreceptors, and choriocapillaris associated with aging participate for visual loss. In 2010, AMD involved 6.6% of all blindness cases around the world. Some of the researches have evaluated the replacing of damaged RPE in AMD patients by using the cells from various sources. Today, the advancement of RPE differentiation or generation from stem cells has been gained, and currently, clinical trials are testing the efficiency and safety of replacing degenerated RPE with healthy RPE. However, the therapeutic success of RPE transplantation may be restricted unless the transplanted cells can be adhered, distributed and survive for long-term in the transplanted site without any infections. In recent years a variety of scaffold types were used as a carrier for RPE transplantation and AMD treatment. In this review, we have discussed types of scaffolds; natural or synthetic, solid or hydrogel and their results in RPE replacement. Eventually, our aim is highlighting the novel and best scaffold carriers that may have potentially promoting the efficacy of RPE transplantation.

Targeting Phosphatidylinositol 3-Kinase Signaling Pathway for Therapeutic Enhancement of Vascular-Targeted Photodynamic Therapy

Vascular-targeted photodynamic therapy (PDT) selectively disrupts vascular function by inducing oxidative damages to the vasculature, particularly endothelial cells. Although effective tumor eradication and excellent safety profile are well demonstrated in both preclinical and clinical studies, incomplete vascular shutdown and angiogenesis are known to cause tumor recurrence after vascular-targeted PDT. We have explored therapeutic enhancement of vascular-targeted PDT with PI3K signaling pathway inhibitors because the activation of PI3K pathway was involved in promoting endothelial cell survival and proliferation after PDT. Here, three clinically relevant small-molecule inhibitors (BYL719, BKM120, and BEZ235) of the PI3K pathway were evaluated in combination with verteporfin-PDT. Although all three inhibitors were able to synergistically enhance PDT response in endothelial cells, PDT combined with dual PI3K/mTOR inhibitor BEZ235 exhibited the strongest synergism, followed in order by combinations with pan-PI3K inhibitor BKM120 and p110α isoform-selective inhibitor BYL719. Combination treatments of PDT and BEZ235 exhibited a cooperative inhibition of antiapoptotic Bcl-2 family protein Mcl-1 and induced more cell apoptosis than each treatment alone. In addition to increasing treatment lethality, BEZ235 combined with PDT effectively inhibited PI3K pathway activation and consequent endothelial cell proliferation after PDT alone, leading to a sustained growth inhibition. In the PC-3 prostate tumor model, combination treatments improved treatment outcomes by turning a temporary tumor regrowth delay induced by PDT alone to a more long-lasting treatment response. Our study strongly supports the combination of vascular-targeted PDT and PI3K pathway inhibitors, particularly mTOR inhibitors, for therapeutic enhancement. Mol Cancer Ther; 16(11); 2422-31. ©2017 AACR.

[Photodynamic therapy. The fields of applications and prospects for the further development in otorhinolaryngology]

This article presents a review of the modern specialized medical literature concerned with the applications of photodynamic therapy (PDT) in otorhinolaryngology and medicine at large. The necessity of such a review of the available possibilities provided by PDT is dictated by the ever increasing interest of otorhinolaryngologists and specialists of other medical disciplines in the use of this method for the treatment of tumours and inflammatory diseases as well as their pyogenic complications. The author offers the critical assessment of the experience gained with the application of the known PDT technologies for the management of various pathological conditions. Especially much attention is given to the treatment of acute and chronic inflammation in the otorhinolaryngological practice with special reference to the yet unresolved problems.

A new kind of labyrinth-like capillary is responsible for leakage from human choroidal neovascular endothelium, as investigated by high-resolution electron microscopy

PURPOSE

This study reports the clinicopathologic findings of leaky sites in pathological vessels after submacular removal of choroidal neovascular membranes (CNV). As the site that causes fluid exudation from neovascular vessels is unknown, specific attention was focused on the formation of fenestrations, cellular junctions, and morphologic alteration which can cause endothelial leakage.

METHODS

Choroidal neovascular membranes of 15 patients who underwent submacular surgery for CNV were investigated. Five patients received bevacizumab treatment before surgery, and another five received photodynamic therapy before surgery. The remaining five did not receive any other treatment before surgery. All membranes were embedded for transmission electron microscopy. CNVs were analyzed for pathological cell-to-cell connections, fenestrations, or other pathological conditions which can cause leakage of plasma.

RESULTS

The morphology of the newly formed blood channels was very variable, and in principle was not different in treated and untreated patients. The sources of leakage in neovascular choroidal vessels were caused by insufficient endothelial cell connections and by capillaries with microvillar projections into the vessel lumen which blocked cellular perfusion but still allowed the flow of plasma. Fenestrations were only infrequently observed.

CONCLUSIONS

A newly discovered type of pathological capillary, called a labyrinth capillary, is very likely responsible for the permanent leakage of fluid. Due to the small vessel lumen, thrombocytes cannot enter these capillaries to close the leakages. Fenestrations did not appear to play a significant role in vascular leakiness.

Evaluation of verteporfin pharmakokinetics--redefining the need of photosensitizers in ophthalmology

INTRODUCTION

The benzoporphyrine derivative verteporfin has lost its importance to the treatment of the most frequent neovascular eye diseases. Nevertheless, it is still mandatory to define the remaining applications, role, and potential of verteporfin in ocular photodynamic therapy (PDT), including the dosages of administration, effectiveness, and safety profile.

AREAS COVERED

Although verteporfin PDT has forfeited the first-line status and value of treating subfoveal choroidal neovascularization (CNV) due to age-related macular degeneration or pathologic myopia, the treatment remains the standard of care for choroidal haemangioma and polypoidal choroidal vasculopathy. PDT is effective in less pigmented choroidal melanoma as well as in retinal vascular proliferations and retinal angioma. Verteporfin was granted the orphan drug designation for the treatment of chronic or recurrent central serous chorioretinopathy (CSC).

EXPERT OPINION

Evidence-based data regarding optimized parameters (low fluence, reduced dose, fractionated irradiation) adapted to the treated diseases (target structure, dosimetry, blood supply) are scarce. Prospective and large clinical trials are missing, although the scientific community agrees on the fact that the standard treatment protocol does not necessarily provide the optimal efficacy to the specific disease or individual patient. Within the reviewed indications, the adverse effect profile is favorable compared with other therapies.

Angiostatic kinase inhibitors to sustain photodynamic angio-occlusion

Targeted angiostatic therapy receives major attention for the treatment of cancer and exudative age-related macular degeneration (AMD). Photodynamic therapy (PDT) has been used as an effective clinical approach for these diseases. As PDT can cause an angiogenic response in the treated tissue, combination of PDT with anti-angiogenic compounds should lead to improved therapy. This study was undertaken to test the clinically used small molecule kinase inhibitors Nexavar® (sorafenib), Tarceva® (erlotinib) and Sutent® (sunitinib) for this purpose, and to compare the results to the combination of Visudyne®-PDT with Avastin® (bevacizumab) treatment. When topically applied to the chicken chorioallantoic membrane at embryo development day (EDD) 7, a clear inhibition of blood vessel development was observed, with sorafenib being most efficient. To investigate the combination with phototherapy, Visudyne®-PDT was first applied on EDD11 to close all <100 μm vessels. Application of angiostatics after PDT resulted in a significant decrease in vessel regrowth in terms of reduced vessel density and number of branching points/mm(2) . As the 50% effective dose (ED50) for all compounds was approximately 10-fold lower, Sorafenib outperformed the other compounds. In vitro, all kinase inhibitors decreased the viability of human umbilical vein endothelial cells. Sunitinib convincingly inhibited the in vitro migration of endothelial cells. These results suggest the therapeutic potential of these compounds for application in combination with PDT in anti-cancer approaches, and possibly also in the treatment of other diseases where angiogenesis plays an important role.

Combined photodynamic therapy and intravitreal bevacizumab for idiopathic polypoidal choroidal vasculopathy: one-year follow-up

OBJECTIVE

To report the efficacy and safety of combined photodynamic therapy (PDT) and intravitreal bevacizumab (IVB) injection in the treatment of idiopathic polypoidal choroidal vasculopathy (IPCV).

MATERIAL AND METHODS

A prospective case series of 10 eyes of 10 consecutive patients affected by IPCV with subfoveal involvement. PDT plus IVB (1.25 mg/0.05 mL) injection two weeks later was performed in all patients. Two adjunctive injections of bevacizumab were scheduled at four and eight weeks after the initial treatment. Best-corrected visual acuity (BCVA), fluorescein and indocyanine green angiographies, and optical coherence tomography were obtained at baseline, and at one, three, six, nine, and 12 months.

RESULTS

The combined treatment led to an improvement of both neurosensory detachment and pigmented epithelial detachment in all eyes, with a decrease of exudation and regression of macular thickness, which remained stable to the end of follow-up. However, BCVA remained stable over the 12 months of follow-up.

CONCLUSION

These findings demonstrate that PDT/IVB combined therapy is able to achieve morphologic stabilization of the IPCV lesion, through a rapid decrease of macular thickness and regression of the size of polypoidal vascular lesion.

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.

Combined intravitreal bevacizumab and photodynamic therapy for neovascular age-related macular degeneration

BACKGROUND

Our aim was to evaluate the short-term safety and efficacy of combined photodynamic therapy (PDT) with verteporfin and intravitreal bevacizumab in neovascular age-related macular degeneration (AMD).

METHODS

A prospective non-randomized interventional case series of 30 eyes of 30 patients with choroidal neovascularization (CNV) caused by AMD was studied. All patients were treated with PDT followed by an intravitreal injection of bevacizumab (1.5 mg) on the same day. Ophthalmic evaluations included determination of best-corrected visual acuity by using ETDRS charts. CNV lesion characteristics were determined by fluorescein angiography, and retinal morphology by optical coherence tomography. Review examinations were performed 1, 4, and 12 weeks following treatment.

RESULTS

The median ETDRS letter scores increased by 3 letters after 4 weeks and 4.3 letters after 12 weeks. Median central retinal thickness decreased from the baseline by 145 microm (week 1), 205 microm (week 4), and 171 microm (week 12), respectively (P < 0.0001, for all comparisons). One patient experienced a transient moderate vision loss after 4 weeks post treatment. Leakage on fluorescein angiography was resolved in all patients at week 12. No significant ocular or systemic side-effects were observed.

CONCLUSIONS

Short-term results suggest that a single PDT in combination with intravitreal bevacizumab is safe and associated with stabilization of visual acuity and decrease of intraretinal and subretinal fluid accumulation in the macula. Further evaluation of this treatment strategy for neovascular AMD appears warranted.

Histopathological findings in postmortem eyes after photodynamic therapy for choroidal neovascularisation in age-related macular degeneration: report of two cases

BACKGROUND

To report the histopathological findings after photodynamic therapy (PDT) in eyes obtained postmortem with choroidal neovascularisation (CNV) secondary to age-related macular degeneration (AMD).

METHODS

Two eyes were obtained postmortem from two patients with CNV secondary to AMD. Both of the patients had been treated with PDT. Serial sections through the posterior poles were obtained and stained with haematoxylin-eosin, periodic acid-Schiff, Masson trichrome or phosphotungstic acid haematoxylin (PTAH). Two-dimensional reconstructions were prepared and compared with fluorescein angiograms.

RESULTS

The interval between PDT and death was 3 months and 17 months in each patient, respectively. Light-microscopic examination showed that CNV enveloped with retinal pigment epithelium (RPE) in both eyes. The average size of the CNV was 550 x 280 microm. One eye had combined (subRPE/subretinal) growth pattern CNV, and the other eye had both type I (subRPE) and combined growth pattern CNV. All specimens contained fibrous proliferation and patent vascular channels within the CNV, and there was no thrombus formation within the vascular channels. No apparent abnormalities in the choroid were observed by light microscopy.

CONCLUSIONS

Although involution with fibrous tissue proliferation occurred, PDT did not result in permanent occlusion of the vascular channels in the CNV. Our findings indicate that PDT may accelerate involution of CNV, thus limiting its size and preserving photoreceptors.

Large submacular hemorrhage following PDT with verteporfin in patients with occult CNVM secondary to age-related macular degeneration

A review of the charts for all patients who developed large submacular hemorrhages following photodynamic therapy for choroidal neovascular membranes secondary to age-related macular degeneration yielded three patients who met the criteria for a large submacular hemorrhage. All three patients were treated for exudative age-related macular degeneration and were taking warfarin for chronic anticoagulation. Before photodynamic therapy, the international normalized ratio ranged from 1.2 to 1.6. All three patients had received at least one previous verteporfin treatment in the study eye. All three hemorrhages were not noted immediately after photodynamic therapy and were documented within 1 to 2 weeks following the procedure. Patients with age-related macular degeneration who are receiving warfarin therapy and undergoing repeat verteporfin treatments appear to be at risk for submacular hemorrhages.

A review of drug options in age-related macular degeneration therapy and potential new agents

Age-related macular degeneration (AMD) is the leading cause of legal blindness in people > 50 years of age in the developed world. AMD is both a debilitating and costly disease for the individual and the community. Greater understanding of the mechanisms and pathways involved in causing the visual loss in AMD has resulted in the advent of several newer and more effective treatment options, making it an exciting time in the management of AMD. This paper will examine the principles behind the existing drug therapies available, as well as those being developed in the management or prophylaxis of AMD and its vision-threatening complications.

Photodynamic therapy of experimental choroidal neovascularization in the mouse

PURPOSE

To evaluate the qualitative and quantitative effects of verteporfin photodynamic therapy (PDT) on laser-induced choroidal neovascularization (CNV) in the mouse.

METHODS

PDT was applied to the normal mouse fundus using light doses of 32, 64, and 83 s, and histological analysis of the treated areas was performed. CNV was induced using krypton laser photocoagulation of the fundus, and the CNV lesions were subsequently treated with PDT using light doses of 32, 64, and 83 s. Enucleated eyes were analyzed with light and transmission electron microscopies, and measurements of CNV size were done on histologic sections and on isolectin B4-stained choroidal flat mounts.

RESULTS

PDT induced a light dose-dependent damage to the surrounding neural retina in normal eyes. At a light dose of 32 s, minimal damage was detected in the neural retina, whereas higher light doses caused distortion and disruption of the outer and inner nuclear layers and of the retinal pigment epithelium. When PDT was applied over laser-induced CNV lesions, the relative height of the lesions was significantly reduced (p < 0.05) using all light doses. Transmission electron microscopy 1 day after PDT treatment revealed occlusion of many of the CNV vessels. One week after PDT treatment, the CNV lesions contained patent vessels irrespective of light dose applied. Accordingly, PDT treatment inhibited (p < 0.05) but did not halt CNV lesion growth.

CONCLUSIONS

PDT treatment of laser-induced CNV may create an acute occlusion of neovessels and an inhibition of CNV lesion growth without apparent injury to the surrounding neural retina. However, PDT-treated areas will remain vascularized with continued growth of the CNV lesion, which in turn may explain the often limited effect of PDT in patients with neovascular age-related macular degeneration. Elevating the PDT light dose will not increase the treatment effect substantially but may lead to increased collateral injury.

Triamcinolone acetonide suppresses early proangiogenic response in retinal pigment epithelial cells after photodynamic therapy in vitro

OBJECTIVE

To investigate the expression of proangiogenic and antiangiogenic factors, vascular endothelial growth factor (VEGF) and pigment epithelium-derived factor (PEDF) in retinal pigment epithelial (RPE) cells after photodynamic therapy (PDT), especially focusing on their change in the presence of triamcinolone acetonide.

METHODS

Firstly, the cellular uptake of verteporfin was quantified after confluent ARPE-19 (human retinal pigment epithelial) cells were exposed to 5 microg/ml verteporfin combined with or without 1 microg/ml triamcinolone acetonide for 1 h. Secondly, ARPE-19 cells exposed to various doses of verteporfin were irradiated with 120 mJ/cm(2) light. After incubation with or without 1 microg/ml triamcinolone acetonide for 2 days, cell viability and expressions of VEGF and PEDF were assessed.

RESULTS

Cellular uptake of verteporfin was not significantly changed by the presence of 1 microg/ml triamcinolone acetonide. In addition, 0.01-0.1 microg/ml of verteporfin showed a dose-dependent toxicity on the ARPE-19 cells 2 days after the light exposure. The presence of verteporfin at a concentration of 0.01 microg/ml did not affect the cell viability but significantly increased VEGF (p<0.001) and reduced PEDF (p = 0.03) expression. Administration of triamcinolone acetonide significantly suppressed both this increase in VEGF (p<0.001) and decrease in PEDF (p = 0.001).

CONCLUSIONS

VEGF was increased and PEDF reduced in cultured RPE cells shortly after PDT even at a sublethal dose. Triamcinolone acetonide suppressed this proangiogenic response.

Retinal pigment epithelium changes after photodynamic therapy for choroidal neovascularization in pathological myopia

PURPOSE

To describe changes in the retinal pigment epithelium (RPE) induced by photodynamic therapy (PDT) in eyes with subfoveal choroidal neovascularization (CNV) associated with pathological myopia (PM).

METHODS

We carried out an open-label, prospective, interventional case series including 26 patients affected by subfoveal CNV in PM who underwent PDT with a 12-month follow-up. Particular attention was paid to the detection of changes at the RPE level in the areas exposed to the laser compared with baseline conditions.

RESULTS

The median age of the patients was 58.5 years and the median duration of symptoms was 2 weeks. A pigmentary zone was present before PDT in 20 eyes (77%), incompletely encircling the CNV in all but two of the 20 eyes. At the end of the follow-up, the CNV in all eyes was seen to be completely or incompletely encircled by a band of hyperpigmentation, which was surrounded by RPE alterations, including depigmentation in all cases and atrophic changes in 14 eyes.

CONCLUSIONS

After PDT, alterations in the RPE develop in myopic eyes. These include accentuation of the pigmentary zone surrounding the CNV and progressive atrophic changes. Further studies are needed to correlate post-PDT RPE damage with longterm visual outcome.

Different transitions of multifocal electroretinogram recordings between patients with age-related macular degeneration and polypoidal choroidal vasculopathy after photodynamic therapy

AIM

To compare and evaluate the transitions in retinal function after photodynamic therapy (PDT) between age-related macular degeneration (AMD) and polypoidal choroidal vasculopathy (PCV) using multifocal electroretinograms (mfERGs).

METHODS

10 eyes with choroidal neovascularisation (CNV) secondary to AMD and 11 eyes with CNV secondary to PCV were included in the study. mfERGs were recorded before PDT, and 1 week and 3 months after PDT. mfERG recordings were acquired by a Veris system (V.3.1.3) using a 103 hexagon stimulus. The first-order kernel was used to calculate amplitudes and latencies. Mean amplitudes and latencies from two central rings rated 0-4 degrees of visual angle were analysed and compared with each disease.

RESULTS

In AMD, the mean first negative peak (N1) amplitudes tended to decrease, and the mean first positive peak (N1P1) amplitudes reduced to significant levels (p = 0.047) 1 week after PDT. 3 months after PDT, there were no significant differences in the mean N1 and N1P1 amplitudes compared with pre-PDT values. In PCV, there were no significant changes in the mean N1 and N1P1 amplitudes 1 week after treatment. However, 3 months after PDT, mean amplitudes showed significant increases in N1 (p = 0.008) and N1P1 (p = 0.006) amplitudes compared with pre-PDT values.

CONCLUSIONS

mfERG recording transitions are different between patients with AMD and those with PCV. In patients with AMD, these results may show transient impairments in retinal function 1 week after PDT, but in those with PCV, the efficacy of PDT is superior to the impairment after PDT.

Photodynamic treatment in a rabbit model of glaucoma surgery

PURPOSE

To evaluate the safety and efficacy of postoperative verteporfin photodynamic treatment as an adjunct to glaucoma experimental filtration surgery in rabbits.

METHODS

Dutch belted (n = 15) rabbits underwent full thickness sclerectomy in one eye. The experimental group (group 1, n = 7) underwent i.v. injection of verteporfin and subsequent photoactivation at the operative site on postoperative day 1 (POD 1). Control groups of animals received either light exposure (group 2, n = 4) or verteporfin (group 3, n = 2), or no intervention (group 4, n = 2). Intraocular pressure (IOP) was measured prior to the procedure (POD 0) and daily thereafter for the first week after sclerectomy (PODs 1-7) and every other day for the second week (PODs 9, 11, 13, 15). Percentage IOP reductions of operated over contralateral control eyes were compared among the various groups. Success rates (percentage IOP reduction > 15%) were also compared between the experimental and control groups. Eyes were histologically examined for evaluation of fibrosis.

RESULTS

Rabbits in the experimental group (group 1) had a mean +/- SEM percentage IOP reduction of 25 +/- 3% during the follow-up period. In contrast, groups 2, 3 and 4 had IOP reductions of 4 +/- 5%, 12 +/- 7% and 4 +/- 6%, respectively (p < 0.005, anova among all four groups). Successful IOP reduction (> or = 15%) over the contralateral eye at POD 15 was achieved in six of seven experimental animals, but only in one of eight control animals (p < 0.02, chi-squared test). Bleb failure occurred significantly earlier in the control eyes compared with eyes receiving PDT (p < 0.003, log rank test). Blebs in the experimental group differed from those in the control groups histologically, lacking significant collagen deposition in the area of the sclerostomy.

CONCLUSIONS

Wound healing in glaucoma surgery may be successfully modulated postoperatively using photodynamic therapy with i.v. administered photosensitizer.

Verteporfin photodynamic therapy induced apoptosis in choroidal neovascular membranes

AIM

To evaluate the impact of verteporfin photodynamic therapy (PDT) on the induction of apoptosis in choroidal neovascular membranes (CNV) secondary to age related macular degeneration.

METHODS

Retrospective review of 22 surgically excised CNV. 12 of these patients had been treated with PDT 3-146 days previously. Apoptotic cells were detected with the TUNEL technique and compared to the expression of CD34 (endothelial cells, EC), CD105 (activated endothelial cells), Ki-67 (proliferation marker), and cytokeratin18 (retinal pigment epithelial cells, RPE).

RESULTS

CNV excised 3 days after PDT were characterised both by collapsed and patent vessels. The EC displayed a statistical significant positive TUNEL reaction when compared to the remaining treated CNV (p < 0.001) and untreated CNV (P = 0.002). The proliferative activity was reduced. CNV excised 1-5 months after PDT displayed a patent vascularisation and high proliferative activity. All membranes either treated or untreated disclosed only sporadic TUNEL positive cells within the stroma and the RPE.

CONCLUSIONS

Verteporfin PDT leads to selective and effective damage of EC within CNV. Both patent and occluded vessels were lined by apoptotic EC. This finding and the increased expression of proliferation marker at later time points suggest that revascularisation after PDT is caused by angiogenesis rather than recanalisation.

Combined photodynamic therapy and intravitreal triamcinolone injection for the treatment of subfoveal choroidal neovascularisation in age related macular degeneration: a comparative study

AIM

To evaluate the outcomes of combined intravitreal triamcinolone (IVTA) and photodynamic therapy (PDT) with verteporfin in the treatment of subfoveal choroidal neovascularisation (CNV) caused by age related macular degeneration (AMD).

METHODS

48 eyes from 48 patients with subfoveal CNV caused by AMD were prospective recruited, with 24 eyes treated with combined PDT with IVTA and compared with a control group of 24 eyes which received PDT monotherapy. In the combined treatment group, IVTA was performed immediately after PDT as an outpatient procedure. The mean number of treatments, mean logMAR best corrected visual acuity (BCVA), mean line of visual acuity changes, and proportion of patients without moderate visual loss at 1 year were compared between the combined and monotherapy groups.

RESULTS

At 1 year the logMAR BCVA for the PDT with IVTA group changed from 0.88 to 0.95 (p = 0.32 compared with baseline), whereas the logMAR BCVA for the monotherapy group reduced from 0.74 to 1.09 (p<0.001 compared with baseline). A significantly higher proportion of patients who had PDT with IVTA did not develop moderate visual loss at 1 year compared with the monotherapy group (70.8% and 33.3% respectively, p = 0.009). Eyes which had combined treatment had significantly fewer lines lost compared with monotherapy alone (0.7 and 3.5 lines respectively, p = 0.015). Subgroup analysis showed that PDT with IVTA is effective in preventing visual loss in both predominately classic and occult CNV groups. The mean number of treatments for the combined and monotherapy groups was 1.5 and 1.96 respectively (p = 0.076).

CONCLUSIONS

Combined PDT with IVTA appeared more effective statistically at 12 months for stabilisation of vision (<3 logMAR lines change) compared with PDT monotherapy. Further randomised control trials might be justified to conclude the efficacy of PDT with IVTA.

Electrooculography After Photodynamic Therapy

PURPOSE

To evaluate the changes in electrooculography (EOG) after photodynamic therapy (PDT).

METHODS

Thirty-eight eyes of 38 patients (21 males, 17 females) with choroidal neovascularization secondary to age related macular degeneration were included in this study. Standart PDT with verteporfin was performed on each patient. Serial EOG recordings were performed before, 1 week, and 1 month after PDT.

RESULTS

Mean age of the patients was 69.8+/-9.7 years (range 56 and 90 years). Seven days after PDT the visual acuity improved in 17 eyes, remained unchanged in 16 eyes and deteriorated in 5 eyes. One month after PDT the visual acuity findings were the same as the first week. New hemorrhages were seen in three eyes in the first week after PDT and visual acuity was decreased in those patients. No other patient complained of ocular and systemic adverse events. There was a statistically significant reduction in the Arden ratio of the EOG 1 week after PDT and the reduction persisted in the first month recordings.

CONCLUSIONS

The reduction in Arden ratio of EOG findings may indicate that retina pigment epithelium function could be affected after PDT.

The Changes of Pattern Electroretinography at the Early Stage of Photodynamic Therapy

PURPOSE

To evaluate the short-term changes in pattern electroretinography (PERG) after photodynamic therapy (PDT).

METHODS

Thirty eyes of 30 patients (17 males, 13 females) with choroidal neovascularization secondary to age related macular degeneration were included in this study. Standard PDT with verteporfin was performed on each patient. Serial PERG recordings were performed before, 1 week, and 1 month after PDT.

RESULTS

Mean age of the patients was 69.6+/-8.4 years (range 56 and 90 years). One month after PDT, the visual acuity improved in 16 eyes, remained unchanged in 12 eyes and deteriorated in two eyes. New hemorrhages were seen in two eyes in the first week after PDT and visual acuity was decreased in those patients. No other patient complained of ocular and systemic adverse events. There was a statistically significant reduction in the amplitudes of P50 and N95 waves at the first week recordings after PDT. At 1 month after PDT, no significant differences in the P50 and N95 amplitudes were observed compared with pre-PDT PERG recordings. There were no significant changes in the latencies of P50 and N95 at the first week and first month recordings when compared with pre-treatment PERG values.

CONCLUSIONS

Reduction in P50 and N95 amplitudes suggests that transient impairments in macular function occur at the first week after PDT.

Anecortave acetate

This manuscript reviews the pharmacotherapeutics of the novel, angiostatic cortisene, anecortave acetate suspension, for the treatment of age-related macular degeneration. The chemistry, pharmacokinetics and pharmacodynamics of anecortave acetate are discussed, and the results of the multi-centre, randomised, controlled clinical trials for the treatment of subfoveal choroidal neovascularisation in age-related macular degeneration summarised. It also discusses ongoing clinical trials involving anecortave acetate for dry and wet age-related macular degeneration.

Treatment of age-related macular degeneration

Age-related macular degeneration (AMD) is the greatest cause of legal blindness in the western world. Established treatments include argon laser photocoagulation of extrafoveal choroidal neovascularisation (CNV) and photodynamic therapy of selected sub-foveal CNV. Newer approaches are targeting the angiogenic pathway in CNV development. Currently, other treatment modalities, such as radiotherapy and transpupillary thermotherapy do not have a clear role to play. Surgical options are experimental and only available in some centres for selected patients. Prevention of AMD remains elusive. Dietary supplements may have a role, while statins and prophylactic laser photocoagulation of drusen remain experimental. This paper explains the principles behind these approaches.

Combined Photodynamic Therapy and Intravitreal Triamcinolone Acetonide Injection for Neovascular Age-Related Macular Degeneration With Pigment Epithelium Detachment

BACKGROUND AND OBJECTIVE

To report the outcome of combined verteporfin photodynamic therapy (PDT) and intravitreal triamcinolone acetonide (IVTA) for the treatment of choroidal neovascularization (CNV) with serous pigment epithelium detachment (PED) due to age-related macular degeneration (AMD).

PATIENTS AND METHODS

The files of all consecutive patients with CNV and serous PED who received PDT and IVTA either primarily (primary treatment group) or following previous unsuccessful PDT (secondary treatment group) were reviewed for visual and angiographic results.

RESULTS

Ten patients (11 eyes) were included. Mean number of PDT sessions was 3.18; 8 eyes received one IVTA injection and 3 eyes received two IVTA injections. Thirty-six percent of patients retained their initial visual acuity after a mean follow-up of 15.3 months. Loss of 3 or more Snellen lines was noted in 2 of 3 eyes in the primary treatment group and 5 of 8 eyes in the secondary treatment group. Increased intraocular pressure developed in 3 patients and was controlled by topical medications.

CONCLUSIONS

Although combined PDT and IVTA may be considered for CNV with serous PED in patients with poor prognosis with PDT alone, the regimen as administered in this small series was not beneficial. Further studies are required to determine whether alternate sequences, timing, or doses would yield a better outcome.

Indocyanine green-mediated photothrombosis with and without intravitreal triamcinolone acetonide for subfoveal choroidal neovascularization in age-related macular degeneration: a pilot study

PURPOSE

To determine the feasibility, safety, and clinical effect of treating patients with subfoveal choroidal neovascularization (CNV) in age-related macular degeneration (AMD) with indocyanine green (ICG)-mediated photothrombosis (IMP) with and without intravitreal triamcinolone acetonide (TA).

METHODS

Fifteen patients (19 eyes) participated in the study. Nine eyes of seven patients were treated with IMP immediately followed by an intravitreal injection of 4 mg of TA (Group A), and 10 eyes of 8 patients were treated with IMP only (Group B). Patients had a mean follow-up of 6.9 months (range: 3 to 12 months). Patients underwent single or two sessions of IMP.

RESULTS

In Group A, visual acuity (VA) showed stability in 6 eyes (66.7%), improvement of VA in 2 eyes (22.2%), and worsening of VA in 1 eye (11.1%). Group B presented VA stability in 9 eyes (90%), and improvement in 1 eye (10%). In total, of the 15 patients (19 eyes) with IMP with or without intravitreal TA, 3 eyes (15.8%) showed improvement, 15 eyes (78.9%) stability, and 1 eye (5.3%) showed worsening of VA. A significant regression of the CNV and diminishing of subretinal fluid was demonstrated with fluorescein angiography and optical coherence tomography in both groups. No patient in Group A required retreatment. Four of 10 eyes (40%) in Group B required one retreatment during the study period.

CONCLUSIONS

ICG-mediated photothrombosis with and without intravitreal TA may provide stability or improvement in visual acuity and fundus findings in subfoveal CNV in AMD. Further evaluation in a multicenter, randomized, placebo-controlled clinical trial with longer follow-up is needed to accurately assess the safety and efficacy of this new treatment modality.

Using optical coherence tomography to monitor photodynamic therapy in age related macular degeneration

PURPOSE

To evaluate the role of optical coherence tomography (OCT) in determining choroidal neovascularization (CNV) activity before and after photodynamic therapy (PDT) in patients with age-related macular degeneration (ARMD).

DESIGN

Prospective observational case series.

METHODS

SETTING

Institutional study. patient population: Fifty-three patients (62 eyes) with ARMD.

OBSERVATION PROCEDURE

Prospective observational case study.

MAIN OUTCOME MEASURES

Presence or absence of leakage on fluorescein angiography, presence of intraretinal or sub-retinal fluid on OCT, and macular and choroidal neovascular complex thickness on OCT.

RESULTS

The macular thickness decreased significantly after PDT (P = .001). However, no significant changes in CNV thickness were measured after PDT (P = .567). Once the diagnosis of ARMD was established before treatment, OCT had a sensitivity of 96.77% for detecting CNV activity. After treatment, OCT had a good sensitivity (95.65%) and a moderate specificity (59.01%) in determining CNV activity, which resulted in a diagnostic efficiency (proportion of correct results) of 82.95%.

CONCLUSIONS

OCT appears to be useful for indicating CNV activity. Therefore, it may serve as a complementary technique for deciding the need for PDT and re-treatment in patients with ARMD.

New and classic insights into presumed ocular histoplasmosis syndrome and its treatment

PURPOSE OF REVIEW

Presumed ocular histoplasmosis syndrome classically presents with atrophic choroidal scars, which are thought to progress into choroidal neovascularization in a small proportion of patients. The pathophysiology of the disease, including its underlying etiology, continues to be controversial and subject to ongoing research. Even more important is the controversy that surrounds the optimal treatment for choroidal neovascularization in patients with presumed ocular histoplasmosis, in particular that of subfoveal localization.

RECENT DEVELOPMENTS

Intense efforts oriented toward defining the most beneficial therapeutic modality have resulted in some well-designed, large studies that evaluated submacular surgery, photodynamic therapies, and anti-angiogenic therapies, as well as small pilot studies exploring new therapeutic approaches for choroidal neovascularization.

SUMMARY

Important results obtained by these studies were recently made public, and the conclusions that may be drawn from them, as well as an update on findings concerning presumed ocular histoplasmosis etiology, epidemiology, and pathophysiology are presented in this report.

Improved photodynamic activity of porphyrin loaded into nanoparticles: an in vivo evaluation using chick embryos

Hydrophobic porphyrins are potentially interesting molecules for the photodynamic therapy (PDT) of solid cancers or ocular vascularization diseases. Their pharmaceutical development is, however, hampered by their lipophilicity, which renders formulation difficult especially when intravenous administration is needed. Encapsulation of a lipophilic derivative of porphyrin, the meso-tetra(p-hydroxyphenyl)porphyrin (p-THPP), into polymeric biodegradable poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles proved to enhance its photodynamic activity against mammary tumour cells when compared to free drug. In order to further investigate these carriers, the efficacy of the encapsulated drug was assessed on the chick embryo chorioallantoic membrane (CAM) model. First, we identified a suitable solvent for the drug in terms of p-THPP solubility and tolerability by chick embryos. This solution was used as a reference. Then, the fluorescence pharmacokinetics and the photodynamic effects of the porphyrin on CAM vessels were evaluated after intravenous administration of either a p-THPP solution (free drug) or the drug loaded into nanoparticles. The results showed that: (i) the drug remained longer in the vascular compartment when incorporated into nanoparticles and (ii) vascular effects of p-THPP after light irradiation were enhanced with nanoparticle carriers. These results are discussed taking into account the extravasation of intravascular circulating photosensitizers and its influence on PDT performance.

Transient reduction in retinal function revealed by multifocal electroretinogram after photodynamic therapy

PURPOSE

To evaluate the early changes in retinal function after photodynamic therapy (PDT) by multifocal electroretinogram (mfERG).

DESIGN

Prospective interventional case series.

METHODS

Seventeen eyes from 17 patients scheduled for standard PDT with verteporfin were prospectively recruited. Patients' diagnoses included choroidal neovascularization (CNV) secondary to age-related macular degeneration, idiopathic CNV, myopic CNV, polypoidal choroidal vasculopathy, and central serous chorioretinopathy. Serial mfERG recordings were performed before PDT, and at 4 days, 2 weeks, and 1 month after PDT. The first-order kernel N1 and P1 mfERG response from the central 0 to 7 degrees and peripheral 7 to 25 degrees were grouped and analyzed. The mean response amplitudes and peak latencies of the mfERG recordings were compared longitudinally.

RESULTS

There were statistically significant reductions in the mean N1 response amplitude for the central group at 4 days (P =.007) and 2 weeks after PDT (P =.024), in the mean P1 response amplitude for both the central (P =.006) and peripheral (P =.013) groups at 4 days, and for the central group at 2 weeks after PDT (P =.017). There were also statistically significant increases in the mean P1 response latencies at 4 days (P =.004) and at 2 weeks (P =.018) after PDT for the central group and at 4 days after PDT (P =.026) for the peripheral group. At 1 month after PDT, no significant differences in the N1 and P1 mean response amplitudes and peak latencies were observed compared with pre-PDT mfERG.

CONCLUSIONS

Transient impairments in retinal function for as long as 2 weeks after PDT were noticed by reduction in response amplitudes and a delay in peak latencies of mfERG. These findings may explain the common adverse event of subjective visual disturbance early after PDT with normal findings in visual acuity and ophthalmoscopy.

Immunohistopathologic evaluation of choroidal neovascular membranes following verteporfin-photodynamic therapy

PURPOSE

To evaluate the vascularization and proliferative activity in choroidal neovascular membranes due to age-related macular degeneration after verteporfin photodynamic therapy and submacular removal.

DESIGN

Interventional case series.

METHODS

In a retrospective review of seven patients who underwent removal of subfoveal classic choroidal neovascular membranes after treatment with photodynamic therapy 3 to 146 days earlier, membranes were stained for CD 34, CD 105, and Ki-67 and correlated with clinical pictures and fluorescein angiography.

RESULTS

Fluorescein angiography performed on the day of surgery disclosed nonperfusion of the treated area 3 days after photodynamic therapy, but perfusion and leakage were seen at greater post-photodynamic therapy intervals. Membranes excised 3 days after photodynamic therapy showed CD34 and CD105 positive, mostly occluded vessels. The endothelial cells appeared damaged. Ki-67 activity was low. In membranes excised 34 to 146 days after photodynamic therapy, all vessels appeared patent and were lined by healthy endothelial cells with strong expression of CD34 and CD105. Ki-67 expression was elevated after 34 days but decreased thereafter.

CONCLUSION

Photodynamic therapy did not cause a general or complete occlusion of vessels within the choroidal neovascular membranes, as suggested by fluorescein angiography 3 days postintervention, but the endothelial cells appeared to be severely damaged. Proliferative activity within these specimens was reduced. At longer intervals after photodynamic therapy, the fibrovascular tissue seemed to recover; perfusion, hyperfluorescence, and leakage of the choroidal neovascular membranes could be detected by fluorescein angiography. The clinical appearance showed a correlation with the immunohistologic characteristics of an increased proliferative activity and patent vascularization.

Thérapie photodynamique et DMLA : arguments pratiques sur la base de cas cliniques pour retraiter ou surveiller lors du suivi

Clinical and angiographic progression after photodynamic therapy (PDT) is usually slow, sometimes fluctuating and therefore difficult to evaluate. After several sessions of PDT, angiographic follow-up remains the basis for therapeutic management involving either a new PDT session or an alternative treatment. It remains difficult, however, to evaluate the activity and progression potential of the remaining neovessels. Imaging (angiography, optical coherence tomography) and functional data both contribute to the therapeutic decision. Certain patients require several sessions for a progressive reduction of the exudation. For others, the persistence of metamorphopsias and accentuation of the scotoma despite the treatment may entail alternative treatment. Thus, a perifoveal photocoagulation can be proposed to limit the extension of the scotoma if after a reasonable number of sessions, central visual acuity is not recovered; direct photocoagulation of a persistent active neovascular contingent, distant from the fixation zone (foveal or exenterated) can be proposed if it remains on the border of a stabilized lesion; the treatment of a feeder vessel can be proposed if it becomes visible and is associated with active neovessels with a persistent central serous detachment of the neuroretina. Lastly, performance status and patient wishes are important elements in the overall therapeutic project, especially if the eye involved is the second eye, in view of quickly initiating low-vision rehabilitation.

Clinicopathological findings of choroidal neovascularisation following verteporfin photodynamic therapy

AIMS

To report the clinicopathologic findings of surgically excised choroidal neovascularisation (CNV) three days after verteporfin photodynamic therapy (PDT).

METHODS

In three patients (three eyes) with age related macular degeneration, the CNV was surgically removed three days after PDT. The CNV specimens were examined by light microscopy.

RESULTS

The patients had subfoveal classic CNV. Fluorescein angiography revealed non-perfusion of the CNV after PDT and before surgery in all eyes. The light microscopy of the CNV membranes showed swollen and damaged endothelium. Thrombus formation or vascular occlusion in the CNV vessels was not detected.

CONCLUSION

PDT did not cause a thrombosis of the vessels within the CNV three days after PDT. Severe endothelial damage of the CNV was observed and is likely a primary effect of PDT. Non-perfusion of the CNV at this stage is possibly secondary to occlusion at a deeper level, namely the underlying feeding choroid.

Histological findings of a surgically excised myopic choroidal neovascular membrane after photodynamic therapy. A case report

BACKGROUND

The authors describe a myopic choroidal neovascular membrane excised 4 months after photodynamic therapy (PDT).

METHODS

A 68-year-old woman with classic choroidal neovascularization (CNV) due to pathologic myopia underwent PDT with verteporfin in the left eye. Four months after treatment a full-thickness macular hole was diagnosed in the same eye and the patient underwent vitrectomy with submacular membranectomy. The subfoveal membrane was studied by light microscopy and immunohistochemical techniques.

RESULTS

Light microscopy showed a thin fibrovascular membrane covered by residual retinal pigment epithelium. The membrane contained homogeneous matrix with small collagen bundles, fibroblasts and small blood vessels. The distribution of blood vessels was nonuniform: extravasated red blood cells, macrophages and other inflammatory elements were not present in the fibrous matrix. Endothelial cells were highlighted by CD34 immunostaining and did not show any significant alteration. There was no evidence of inflammatory cells or thrombosis inside vascular lumina.

CONCLUSIONS

Histologic examination of the neovascular membrane showed features similar to those of surgically excised myopic CNV without PDT treatment. Our findings suggest that PDT-induced occlusion is temporary. Fluorescein leakage from CNV after a single PDT treatment can be considered as an sign of blood vessel regrowth or recanalization indicating that multiple treatments are necessary.

Photodynamic therapy for age-related macular degeneration in a clinical setting: visual results and angiographic patterns

PURPOSE

To evaluate the visual outcome of patients with subfoveal choroidal neovascularization due to age-related macular degeneration, who received photodynamic therapy (PTD) in a clinical setting and to identify potential predictive visual and angiographic factors.

DESIGN

Interventional case series.

METHODS

The study included 74 patients with subfoveal choroidal neovascularization who underwent PDT from January 2000 to March 2001 and completed at least 1 year follow-up. All patients received verteporfin PDT and were followed clinically, with fluorescein angiography (74 eyes), and with indocyanine green angiography (65 eyes). A review of the medical records and angiograms was performed.

RESULTS

Mean follow-up was 15.6 months. Patients received a mean of 3.4 treatments per year. Sixty-six percent lost less than 3 Snellen lines of visual acuity. Three patients (4%) experienced profound visual acuity loss to finger counting. Final visual acuity was positively correlated with lesion size and visual acuity at presentation. Visual outcome was worse in the presence of cystoid macular edema. On indocyanine green angiography, a round hypofluorescent spot was seen at the site of the PDT, with maintenance of medium and large choroidal vessels.

CONCLUSION

Smaller lesion size and better visual acuity at presentation were good predictive signs, whereas cystoid macular edema was found to be a poor prognostic sign for visual outcome following PDT.