Verteporfin photodynamic therapy for subfoveal choroidal neovascularization in pathologic myopia: a 12-month retrospective review

Cyclic RGD Peptide Targeting Coated Nano Drug Co-Delivery System for Therapeutic Use in Age-Related Macular Degeneration Disease

Vascular endothelial growth factor (VEGF) expression increased significantly in the pathogenesis of age-related macular degeneration, which induced the formation of pathological blood vessels. Dexamethasone is an exogenous anti-angiogenic drug while bevacizumab is an endogenous anti-angiogenic drug. They both have been widely used in ophthalmology. However, independent administration is not enough to completely block the development of choroidal neovascularization (CNV), and the number of eyes vitreous injections is limited. Reasonable combination of drugs may produce significantly better therapeutic effect than single drug treatment. The cyclic RGD (cRGD) peptide has a particularly high affinity with retinal pigment epithelial cells, where VEGF secretes from. In this study, we prepared nanoparticles of bevacizumab and dexamethasone with cRGD peptide as the target (aBev/cRGD-DPPNs). The particle size of the aBev/cRGD-DPPNs was 213.8 ± 1.5 nm, SEM results showed that the nano-carriers were well dispersed and spherical. The cell uptake study demonstrated the selectivity of the aBev/cRGD-DPPN to ARPE-19 with α_Vβ₃ over expressed. The aBev/cRGD-DPPNs had a better apoptosis induction effect and an obvious inhibitory effect on migration, invasion, and capillary-like structures formation of human umbilical vein epithelial cells. The fluorescein fundus angiography study, immunohistochemistry and histopathological evaluation showed the aBev/cRGD-DPPNs greatly reduced the development of CNV on a rabbit model.

Self-assembled IR780-loaded transferrin nanoparticles as an imaging, targeting and PDT/PTT agent for cancer therapy

Combination of photothermal and photodynamic therapy (PTT/PDT) offer unique advantages over PDT alone. However, to achieve synergetic PDT/PTT effect, one generally needs two lasers with different wavelengths. Near-infrared dye IR-780 could be used as photosensitizer both for PTT and PDT, but its lipophilicity limits its practical use and in vivo efficiency. Herein, a simple multifunctional IR780-loaded nanoplatform based on transferrin was developed for targeted imaging and phototherapy of cancer compatible with a single-NIR-laser irradiation. The self-assembled transferrin-IR780 nanoparticles (Tf-IR780 NPs) exhibited narrow size distribution, good photo-stability, and encouraging photothermal performance with enhanced generation of ROS under laser irradiation. Following intravenous injection, Tf-IR780 NPs had a high tumor-to-background ratio in CT26 tumor-bearing mice. Treatment with Tf-IR780 NPs resulted in significant tumor suppression. Overall, the Tf-IR780 NPs show notable targeting and theranostic potential in cancer therapy.

Effect of Factor XIII-A G185T Polymorphism on Visual Prognosis after Photodynamic Therapy for Neovascular Macular Degeneration

Macular degenerations represent leading causes of central blindness or low vision in developed countries. Most of these severe visual disabilities are due to age-related macular degeneration (AMD) and pathologic myopia (PM), both of which are frequently complicated by subfoveal choroidal neovascularization (CNV). Photodynamic therapy with verteporfin (PDT-V) is still employed for CNV treatment in selected cases or in combined regimen. In Caucasian patients, the common polymorphism G185T of factor XIII-A gene (FXIII-A-G185T; rs5985) has been described as predictor of poor angiographic CNV responsiveness to PDT-V. Nevertheless, the prognostic implications of this pharmacogenetic determinant on long-term visual outcome after a PDT-V regimen have not been evaluated. We retrospectively selected Caucasian patients presenting with treatment-naive CNV and receiving standardized PDT-V protocol for two years. The study population included patients affected by subfoveal CNV secondary to AMD or PM. We assessed the correlations between the polymorphic allele T of FXIII-A-G185T and: (1) total number of photodynamic treatments; and (2) change in visual acuity from baseline to the end of the follow-up period. Considering a total study population of 412 patients with neovascular AMD or PM, the carriers of 185 T-allele of FXIII-A (GT or TT genotype) received a higher number of photodynamic treatments than patients without it (GG wild-type genotype) (p < 0.01; mean number of PDT-V: 5.51 vs. 3.76, respectively). Moreover, patients with 185 T-allele of FXIII-A had a more marked worsening of visual acuity at 24 months than those with the GG-185 wild genotype (p < 0.01; mean difference in logMAR visual acuity: 0.22 vs. 0.08, respectively). The present findings show that the G185T polymorphism of the FXIII-A gene is associated with significant differences in the long-term therapeutic outcomes of patients treated with standardized PDT-V protocol. The comprehensive appraisal of both anti-thrombophilic effects due to FXIII-A G185T variant and photo-thrombotic action of PDT-V toward CNV provides several clues about the rationale of this intriguing pharmacogenetic correlation. Further investigations are warranted to outline the appropriate paradigm for guiding PDT-V utilization in the course of the combined therapeutic protocol for neovascular macular degeneration.

Genetic predictors of response to photodynamictherapy

In Western countries, therapeutic management of patients affected by choroidal neovascularization (CNV) secondary to different typologies of macular degeneration represents a major health care problem. Age-related macular degeneration is the disease most frequently associated with CNV development. Schematically, CNVs can be distinguished into classic and occult subtypes, which are characterized by variable natural history and different responsiveness to some therapeutic procedures. At present, the dramatic vision loss due to CNV can be mainly treated by two interventional strategies, which are utilizable in either single or combined modalities: photodynamic therapy with verteporfin (PDT-V), and intravitreal administration of drugs acting against vascular endothelial growth factor. The combined use of PDT-V and anti-angiogenic drugs represents one of the most promising strategies against neovascular macular degeneration, but it unavoidably results in an expensive increase in health resource utilization. However, the positive data from several studies serve as a basis for reconsidering the role of PDT-V, which has undergone a renaissance prompted by the need for a more rational therapeutic approach toward CNV. New pharmacogenetic knowledge of PDT-V points to exploratory prospects to optimize the clinical application of this intriguing photothrombotic procedure. In fact, a Medline search provides data regarding the role of several single nucleotide polymorphisms (SNPs) as genetic predictors of CNV responsiveness to PDT-V. Specifically, correlations between SNPs and different levels of PDT-V efficacy have been detected by examining the gene variants influencing (i) thrombo-coagulative pathways, i.e. methylenetetrahydrofolate reductase (MTHFR) 677C>T (rs1801133), factor V (F5) 1691G>A (rs6025), prothrombin (F2) 20210G>A (rs1799963), and factor XIII-A (F13A1) 185G>T (rs5985); (ii) complement activation and/or inflammatory processes, i.e. complement factor H (CFH) 1277T>C (rs1061170), high-temperature requirement factor A1 (HTRA1) promoter -512G>A (rs11200638), and two variants of the C-reactive protein (CRP) gene (rs2808635 and rs876538); and (iii) production and bioavailability of vascular endothelial growth factor (VEGFA -2578C>A [rs699947] and rs2146323). This article critically evaluates both the clinical plausibility and the opportunity to utilize the most important SNP-response interactions of PDT-V for an effective upgrade of the current anti-CNV therapeutic scenario. In addition, the pharmacogenetics of a very severe post-PDT-V adverse event, i.e. a decrease in acute vision, is briefly discussed. A comprehensive appraisal of the findings reviewed in this article should be carefully considered to design future trials aimed at verifying (after proper genotypic stratification of the enrolled patients) whether these innovative pharmacogenetic approaches will be able to improve the multifaceted interventional management of neovascular macular degeneration.