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Karatoprak GŞ, Küpeli Akkol E, Genç Y, Bardakcı H, Yücel Ç, Sobarzo-Sánchez E. Combretastatins: An Overview of Structure, Probable Mechanisms of Action and Potential Applications. Molecules 2020; 25:E2560. [PMID: 32486408 PMCID: PMC7321081 DOI: 10.3390/molecules25112560] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2020] [Revised: 05/25/2020] [Accepted: 05/26/2020] [Indexed: 01/08/2023] Open
Abstract
Combretastatins are a class of closely related stilbenes (combretastatins A), dihydrostilbenes (combretastatins B), phenanthrenes (combretastatins C) and macrocyclic lactones (combretastatins D) found in the bark of Combretum caffrum (Eckl. & Zeyh.) Kuntze, commonly known as the South African bush willow. Some of the compounds in this series have been shown to be among the most potent antitubulin agents known. Due to their structural simplicity many analogs have also been synthesized. Combretastatin A4 phosphate is the most frequently tested compounds in preclinical and clinical trials. It is a water-soluble prodrug that the body can rapidly metabolize to combretastatin A4, which exhibits anti-tumor properties. In addition, in vitro and in vivo studies on combretastatins have determined that these compounds also have antioxidant, anti-inflammatory and antimicrobial effects. Nano-based formulations of natural or synthetic active agents such as combretastatin A4 phosphate exhibit several clear advantages, including improved low water solubility, prolonged circulation, drug targeting properties, enhanced efficiency, as well as fewer side effects. In this review, a synopsis of the recent literature exploring the combretastatins, their potential effects and nanoformulations as lead compounds in clinical applications is provided.
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Affiliation(s)
- Gökçe Şeker Karatoprak
- Department of Pharmacognosy, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey;
| | - Esra Küpeli Akkol
- Department of Pharmacognosy Faculty of Pharmacy, Gazi University, 06330 Ankara, Turkey
| | - Yasin Genç
- Department of Pharmacognosy, Faculty of Pharmacy, Hacettepe University, 06100 Sıhhiye, Ankara, Turkey;
| | - Hilal Bardakcı
- Department of Pharmacognosy, Faculty of Pharmacy, Acibadem Mehmet Ali Aydınlar University, 34752 Istanbul, Turkey;
| | - Çiğdem Yücel
- Department of Pharmaceutical Technology, Faculty of Pharmacy, Erciyes University, 38039 Kayseri, Turkey;
| | - Eduardo Sobarzo-Sánchez
- Instituto de Investigación e Innovación en Salud, Facultad de Ciencias de la Salud, Universidad Central de Chile, Santiago 8330507, Chile;
- Department of Organic Chemistry, Faculty of Pharmacy, University of Santiago de Compostela, 15782 Santiago de Compostela, Spain
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Nainwal LM, Alam MM, Shaquiquzzaman M, Marella A, Kamal A. Combretastatin-based compounds with therapeutic characteristics: a patent review. Expert Opin Ther Pat 2019; 29:703-731. [PMID: 31369715 DOI: 10.1080/13543776.2019.1651841] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Combretastatins represent a potent class of phenolic-stilbene natural products that function as colchicine binding site inhibitors of tubulin polymerization and have been advanced as promising anticancer lead compounds. Among them, combretastatin A-4 is the most potent lead molecule due to its broad spectrum cytotoxicity against a variety of tumors. However, low water solubility due to its high lipophilic nature and inter-conversion of olefinic double bond from more active cis to less active trans-conformation poses limitations to its clinical utility. However, different approaches including prodrugs, salt formations, structural modifications, prevention of inter-conversion of the olefinic bond and changes to the substitution pattern on the rings of combretastatin A-4 were investigated and successfully resulted in different combretastatin-based molecules that demonstrated varying levels of potency against different types of tumors during their in-vitro and in-vivo studies. Areas covered: This review covers the patents over a period of 2008-2018. Expert opinion: Molecular hybridization and prodrug designing imparted multi-targeted actions to combretastatin derivatives. Currently, various combretastatin derivatives are under clinical trials. These derivatives could be used to treat disorders other than cancer, due to their vascular disrupting action.
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Affiliation(s)
- Lalit Mohan Nainwal
- Drug Design & Medicinal Chemistry Lab, Department of Pharmaceutical Chemistry, School of Pharmaceutical Education and Research , New Delhi , India
| | - Mohammad Mumtaz Alam
- Drug Design & Medicinal Chemistry Lab, Department of Pharmaceutical Chemistry, School of Pharmaceutical Education and Research , New Delhi , India
| | - Mohammad Shaquiquzzaman
- Drug Design & Medicinal Chemistry Lab, Department of Pharmaceutical Chemistry, School of Pharmaceutical Education and Research , New Delhi , India
| | - Akranth Marella
- Regulatory Affairs Division, Genpact India Pvt Ltd , Mumbai , India
| | - Ahmed Kamal
- Drug Design & Medicinal Chemistry Lab, Department of Pharmaceutical Chemistry, School of Pharmaceutical Education and Research , New Delhi , India
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Bee YS, Ma YL, Chen J, Tsai PJ, Sheu SJ, Lin HC, Huang H, Liu GS, Tai MH. Inhibition of Experimental Choroidal Neovascularization by a Novel Peptide Derived from Calreticulin Anti-Angiogenic Domain. Int J Mol Sci 2018; 19:ijms19102993. [PMID: 30274378 PMCID: PMC6213176 DOI: 10.3390/ijms19102993] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 09/24/2018] [Accepted: 09/25/2018] [Indexed: 12/11/2022] Open
Abstract
Choroidal neovascularization (CNV) is a key pathological feature of several leading causes of vision loss including neovascular age-related macular degeneration. Here, we show that a calreticulin anti-angiogenic domain (CAD)-like peptide 27, CAD27, inhibited in vitro angiogenic activities, including tube formation, migration of endothelial cells, and vascular sprouting from rat aortic ring explants. In a rat model of laser-induced CNV, we demonstrate that intravitreal injection of CAD27 significantly attenuated the formation of CNV lesions as measured via fundus fluorescein angiography and choroid flat-mounts (19.5% and 22.4% reductions at 10 μg and 20 μg of CAD27 injected, respectively). Similarly, the reduction of CNV lesions was observed in rats that had received topical applications of CAD27 (choroid flat-mounts: 17.9% and 32.5% reductions at 10 μg/mL and 20 μg/mL of CAD27 instilled, respectively). Retinal function was unaffected, as measured using electroretinography in both groups receiving interareal injection or topical applications of CAD27 for at least fourteen days. These findings show that CAD27 can be used as a potential therapeutic alternative for targeting CNV in diseases such as neovascular age-related macular degeneration.
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Affiliation(s)
- Youn-Shen Bee
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
- Yuh-Ing Junior College of Health Care & Management, Kaohsiung 807, Taiwan.
- National Defense Medical Center, Taipei 114, Taiwan.
| | - Yi-Ling Ma
- Division of Nephrology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Jinying Chen
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia.
- Department of Ophthalmology, Jinan University, Guangzhou 510632, China.
| | - Pei-Jhen Tsai
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Shwu-Jiuan Sheu
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
- School of Medicine, National Yang-Ming University, Taipei 112, Taiwan.
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Hsiu-Chen Lin
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Hu Huang
- Aier Eye Institute, Aier School of Ophthalmology, Central South University, Changsha 410083, China.
| | - Guei-Sheung Liu
- Menzies Institute for Medical Research, University of Tasmania, Hobart, TAS 7000, Australia.
- Department of Ophthalmology, Jinan University, Guangzhou 510632, China.
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, VIC 3002, Australia.
| | - Ming-Hong Tai
- Department of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
- Center for Neuroscience, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
- Doctoral Degree Program in Marine Biotechnology, National Sun Yat-Sen University, Kaohsiung 804, Taiwan.
- Graduate Institute of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan.
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Bee YS, Tu L, Sheu SJ, Lin HC, Tang JH, Wang JH, Prea SM, Dusting GJ, Wu DC, Zhong J, Bui BV, Tai MH, Liu GS. Gene Delivery of Calreticulin Anti-Angiogenic Domain Attenuates the Development of Choroidal Neovascularization in Rats. Hum Gene Ther 2017; 28:403-414. [DOI: 10.1089/hum.2016.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Youn-Shen Bee
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Yuh-Ing Junior College of Health Care and Management, Kaohsiung, Taiwan
- National Defense Medical Center, Taipei, Taiwan
| | - Leilei Tu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Shwu-Jiuan Sheu
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- School of Medicine, National Yang-Ming University, Taipei, Taiwan
| | - Hsiu-Chen Lin
- Department of Ophthalmology, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Jia-Hua Tang
- Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Jiang-Hui Wang
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
| | - Selwyn M. Prea
- Department of Optometry and Vision Sciences, University of Melbourne, East Melbourne, Australia
| | - Gregory J. Dusting
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
| | - Deng-Chyang Wu
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Division of Gastroenterology, Department of Internal Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Jingxiang Zhong
- Department of Ophthalmology, the First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Bang V. Bui
- Department of Optometry and Vision Sciences, University of Melbourne, East Melbourne, Australia
| | - Ming-Hong Tai
- Center for Stem Cell Research, Kaohsiung Medical University, Kaohsiung, Taiwan
- Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, Taiwan
- Center for Neuroscience, National Sun Yat-Sen University, Kaohsiung, Taiwan
| | - Guei-Sheung Liu
- Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, East Melbourne, Australia
- Ophthalmology, Department of Surgery, University of Melbourne, East Melbourne, Australia
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Wang T, Wang Q, Song R, Zhang Y, Zhang K, Yuan Y, Bian J, Liu X, Gu J, Liu Z. Autophagy Plays a Cytoprotective Role During Cadmium-Induced Oxidative Damage in Primary Neuronal Cultures. Biol Trace Elem Res 2015; 168:481-9. [PMID: 26041154 DOI: 10.1007/s12011-015-0390-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 05/26/2015] [Indexed: 11/30/2022]
Abstract
Cadmium (Cd) induces significant oxidative damage in cells. Recently, it was reported that autophagy could be induced by Cd in neurons. However, little is known about the role of reactive oxygen species (ROS) during Cd-induced autophagy. In our study, we examined the cross-talk between ROS and autophagy by using N-acetyl cysteine (NAC, an antioxidant) and chloroquine (CQ, a pharmacological inhibitor of autophagy) in a primary rat neuronal cell cultures. We observed accumulation of acidic vesicular organelles and the increased expression of endogenous protein light chain 3 (LC3) in Cd-treated neurons, revealing that Cd induced a high level of autophagy. Moreover, increased levels of ROS were observed in neurons treated with Cd, showing that ROS accumulation was closely associated with neuron's exposure to Cd. Furthermore, we found that autophagy was inhibited by using CQ and/or NAC with further aggravation of mitochondrial damage, lactate dehydrogenase (LDH) leakage and hypoploid apoptotic cell number in Cd-treated neurons. These results proved that autophagy has a cytoprotective role during Cd-induced toxicity in neurons, and it can prevent the oxidative damage. These findings may enable the development of novel therapeutic strategies for neurological diseases.
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Affiliation(s)
- Tao Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Qiwen Wang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
- Bijie Pilot Area Research Institute of Bijie University, Bijie, 551700, People's Republic of China
| | - Ruilong Song
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Yajing Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Kangbao Zhang
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Yan Yuan
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Jianchun Bian
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Xuezhong Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Jianhong Gu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China
| | - Zongping Liu
- College of Veterinary Medicine, Yangzhou University, Yangzhou, 225009, People's Republic of China.
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou, 225009, People's Republic of China.
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Sulaiman RS, Basavarajappa HD, Corson TW. Natural product inhibitors of ocular angiogenesis. Exp Eye Res 2014; 129:161-71. [PMID: 25304218 DOI: 10.1016/j.exer.2014.10.002] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 10/03/2014] [Accepted: 10/06/2014] [Indexed: 12/21/2022]
Abstract
Natural products are characterized by high chemical diversity and biochemical specificity; therefore, they are appealing as lead compounds for drug discovery. Given the importance of angiogenesis to many pathologies, numerous natural products have been explored as potential anti-angiogenic drugs. Ocular angiogenesis underlies blinding eye diseases such as retinopathy of prematurity (ROP) in children, proliferative diabetic retinopathy (DR) in adults of working age, and age-related macular degeneration (AMD) in the elderly. Despite the presence of effective therapy in many cases, these diseases are still a significant health burden. Anti-VEGF biologics are the standard of care, but may cause ocular or systemic side effects after intraocular administration and patients may be refractory. Many anti-angiogenic compounds inhibit tumor growth and metastasis alone or in combination therapy, but a more select subset of them has been tested in the context of ocular neovascular diseases. Here, we review the promise of natural products as anti-angiogenic agents, with a specific focus on retinal and choroidal neovascularization. The multifunctional curcumin and the chalcone isoliquiritigenin have demonstrated promising anti-angiogenic effects in mouse models of DR and choroidal neovascularization (CNV) respectively. The homoisoflavanone cremastranone and the flavonoid deguelin have been shown to inhibit ocular neovascularization in more than one disease model. The isoflavone genistein and the flavone apigenin on the other hand are showing potential in the prevention of retinal and choroidal angiogenesis with long-term administration. Many other products with anti-angiogenic potential in vitro such as the lactone withaferin A, the flavonol quercetin, and the stilbenoid combretastatin A4 are awaiting investigation in different ocular disease-relevant animal models. These natural products may serve as lead compounds for the design of more specific, efficacious, and affordable drugs with minimal side effects.
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Affiliation(s)
- Rania S Sulaiman
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Biochemistry, Faculty of Pharmacy, Cairo University, Cairo, Egypt
| | - Halesha D Basavarajappa
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Timothy W Corson
- Eugene and Marilyn Glick Eye Institute, Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Pharmacology and Toxicology, Indiana University School of Medicine, Indianapolis, IN, United States; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States; Melvin and Bren Simon Cancer Center, Indiana University School of Medicine, Indianapolis, IN, United States.
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7
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Mukhtar E, Adhami VM, Mukhtar H. Targeting microtubules by natural agents for cancer therapy. Mol Cancer Ther 2014; 13:275-84. [PMID: 24435445 DOI: 10.1158/1535-7163.mct-13-0791] [Citation(s) in RCA: 371] [Impact Index Per Article: 37.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Natural compounds that target microtubules and disrupt the normal function of the mitotic spindle have proven to be one of the best classes of cancer chemotherapeutic drugs available in clinics to date. There is increasing evidence showing that even minor alteration of microtubule dynamics can engage the spindle checkpoint, arresting cell-cycle progression at mitosis and subsequently leading to cell death. Our improved understanding of tumor biology and our continued appreciation for what the microtubule targeting agents (MTAs) can do have helped pave the way for a new era in the treatment of cancer. The effectiveness of these agents for cancer therapy has been impaired, however, by various side effects and drug resistance. Several new MTAs have shown potent activity against the proliferation of various cancer cells, including resistance to the existing MTAs. Sustained investigation of the mechanisms of action of MTAs, development and discovery of new drugs, and exploring new treatment strategies that reduce side effects and circumvent drug resistance could provide more effective therapeutic options for patients with cancer. This review focuses on the successful cancer chemotherapy from natural compounds in clinical settings and the challenges that may abort their usefulness.
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Affiliation(s)
- Eiman Mukhtar
- Corresponding Author: Hasan Mukhtar, Department of Dermatology, University of Wisconsin-Madison, 410 Medical Sciences Center, 1300 University Avenue, Madison, WI 53706.
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Reynolds AL, Kent D, Kennedy BN. Current and Emerging Therapies for Ocular Neovascularisation. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2014; 801:797-804. [DOI: 10.1007/978-1-4614-3209-8_100] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Novack GD. Translating Drugs From Animals to Humans: Do We Need to Prove Efficacy? Transl Vis Sci Technol 2013; 2:1. [PMID: 24078898 PMCID: PMC3783258 DOI: 10.1167/tvst.2.6.1] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Accepted: 08/02/2013] [Indexed: 01/30/2023] Open
Affiliation(s)
- Gary D Novack
- PharmaLogic Development, Inc., San Rafael, California
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10
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Microvascular complications and diabetic retinopathy: recent advances and future implications. Future Med Chem 2013; 5:301-14. [PMID: 23464520 DOI: 10.4155/fmc.12.206] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Retinal microvascular alterations have been observed during diabetic retinopathy (DR) due to the retinal susceptibility towards subtle pathological alterations. Therefore, retinal microvascular pathology is essential to understand the nature of retinal degenerations during DR. In this review, the role of retinal microvasculature complications during progression of DR, along with recent efforts to normalize such alterations for better therapeutic outcome, will be underlined. In addition, current therapeutics and future directions for advancement of standard treatment for DR patients will be discussed.
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Tubulin-interactive stilbene derivatives as anticancer agents. Cell Mol Biol Lett 2013; 18:368-97. [PMID: 23818224 PMCID: PMC6275897 DOI: 10.2478/s11658-013-0094-z] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 06/20/2013] [Indexed: 02/03/2023] Open
Abstract
Microtubules are dynamic polymers that occur in eukaryotic cells and play important roles in cell division, motility, transport and signaling. They form during the process of polymerization of α- and β-tubulin dimers. Tubulin is a significant and heavily researched molecular target for anticancer drugs. Combretastatins are natural cis-stilbenes that exhibit cytotoxic properties in cultured cancer cells in vitro. Combretastatin A-4 (3′-hydroxy-3,4,4′, 5-tetramethoxy-cis-stilbene; CA-4) is a potent cytotoxic cis-stilbene that binds to β-tubulin at the colchicine-binding site and inhibits tubulin polymerization. The prodrug CA-4 phosphate is currently in clinical trials as a chemotherapeutic agent for cancer treatment. Numerous series of stilbene analogs have been studied in search of potent cytotoxic agents with the requisite tubulin-interactive properties. Microtubule-interfering agents include numerous CA-4 and transresveratrol analogs and other synthetic stilbene derivatives. Importantly, these agents are active in both tumor cells and immature endothelial cells of tumor blood vessels, where they inhibit the process of angiogenesis. Recently, computer-aided virtual screening was used to select potent tubulin-interactive compounds. This review covers the role of stilbene derivatives as a class of antitumor agents that act by targeting microtubule assembly dynamics. Additionally, we present the results of molecular modeling of their binding to specific sites on the α- and β-tubulin heterodimer. This has enabled the elucidation of the mechanism of stilbene cytotoxicity and is useful in the design of novel agents with improved anti-mitotic activity. Tubulin-interactive agents are believed to have the potential to play a significant role in the fight against cancer.
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Ibrahim MA, Do DV, Sepah YJ, Shah SM, Van Anden E, Hafiz G, Donahue JK, Rivers R, Balkissoon J, Handa JT, Campochiaro PA, Nguyen QD. Vascular disrupting agent for neovascular age related macular degeneration: a pilot study of the safety and efficacy of intravenous combretastatin A-4 phosphate. BMC Pharmacol Toxicol 2013; 14:7. [PMID: 23316779 PMCID: PMC3552984 DOI: 10.1186/2050-6511-14-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Accepted: 01/02/2013] [Indexed: 11/21/2022] Open
Abstract
Background This study was designed to assess the safety, tolerability, and efficacy of intravenous infusion of CA4P in patients with neovascular age-related macular degeneration (AMD). Methods Prospective, interventional, dose-escalation clinical trial. Eight patients with neovascular AMD refractory to at least 2 sessions of photodynamic therapy received CA4P at a dose of 27 or 36 mg/m2 as weekly intravenous infusion for 4 consecutive weeks. Safety was monitored by vital signs, ocular and physical examinations, electrocardiogram, routine laboratory tests, and collection of adverse events. Efficacy was assessed using retinal fluorescein angiography, optical coherence tomography, and best corrected visual acuity (BCVA). Results The most common adverse events were elevated blood pressure (46.7%), QTc prolongation (23.3%), elevated temperature (13.3%), and headache (10%), followed by nausea and eye injection (6.7%). There were no adverse events that were considered severe in intensity and none resulted in discontinuation of treatment. There was reduction of the excess foveal thickness by 24.15% at end of treatment period and by 43.75% at end of the two-month follow-up (p = 0.674 and 0.161, respectively). BCVA remained stable throughout the treatment and follow-up periods. Conclusions The safety profile of intravenous CA4P was consistent with that reported in oncology trials of CA4P and with the class effects of vascular disruptive agents; however, the frequency of adverse events was different. There are evidences to suggest potential efficacy of CA4P in neovascular AMD. However, the level of systemic safety and efficacy indicates that systemic CA4P may not be suitable as an alternative monotherapy to current standard-of-care therapy. Trial registration ClinicalTrials.gov NCT01570790.
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Affiliation(s)
- Mohamed A Ibrahim
- Wilmer Eye Institute, Johns Hopkins University School of Medicine, 600 North Wolfe Street, Baltimore, MD 21287, USA
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Zhang K, Zhang L, Weinreb RN. Ophthalmic drug discovery: novel targets and mechanisms for retinal diseases and glaucoma. Nat Rev Drug Discov 2012; 11:541-59. [PMID: 22699774 DOI: 10.1038/nrd3745] [Citation(s) in RCA: 235] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Blindness affects 60 million people worldwide. The leading causes of irreversible blindness include age-related macular degeneration, retinal vascular diseases and glaucoma. The unique features of the eye provide both benefits and challenges for drug discovery and delivery. During the past decade, the landscape for ocular drug therapy has substantially changed and our knowledge of the pathogenesis of ophthalmic diseases has grown considerably. Anti-angiogenic drugs have emerged as the most effective form of therapy for age-related macular degeneration and retinal vascular diseases. Lowering intraocular pressure is still the mainstay for glaucoma treatment but neuroprotective drugs represent a promising next-generation therapy. This Review discusses the current state of ocular drug therapy and highlights future therapeutic opportunities.
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Affiliation(s)
- Kang Zhang
- Department of Ophthalmology and Molecular Medicine Research Center, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu 610041, China.
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14
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Yuan A, Kaiser PK. Emerging therapies for the treatment of neovascular age related macular degeneration. Semin Ophthalmol 2011; 26:149-55. [PMID: 21609228 DOI: 10.3109/08820538.2011.570846] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Numerous drugs that show promise in the treatment of neovascular age related macular degeneration are currently being evaluated in early clinical trials. Some of these drugs target the vascular endothelial growth factor pathway while others act on different targets along the angiogenesis cascade. The mechanism of action of these novel therapeutics and the results of early clinical trials will be discussed along with a review of angiogenesis.
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Affiliation(s)
- Alex Yuan
- Cole Eye Institute, Cleveland, OH 44195, USA
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Inflammatory mediators and angiogenic factors in choroidal neovascularization: pathogenetic interactions and therapeutic implications. Mediators Inflamm 2010; 2010. [PMID: 20871825 PMCID: PMC2943126 DOI: 10.1155/2010/546826] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2010] [Accepted: 07/02/2010] [Indexed: 01/22/2023] Open
Abstract
Choroidal neovascularization (CNV) is a common and severe complication in heterogeneous diseases affecting the posterior segment of the eye, the most frequent being represented by age-related macular degeneration. Although the term may suggest just a vascular pathological condition, CNV is more properly definable as an aberrant tissue invasion of endothelial and inflammatory cells, in which both angiogenesis and inflammation are involved. Experimental and clinical evidences show that vascular endothelial growth factor is a key signal in promoting angiogenesis. However, many other molecules, distinctive of the inflammatory response, act as neovascular activators in CNV. These include fibroblast growth factor, transforming growth factor, tumor necrosis factor, interleukins, and complement. This paper reviews the role of inflammatory mediators and angiogenic factors in the development of CNV, proposing pathogenetic assumptions of mutual interaction. As an extension of this concept, new therapeutic approaches geared to have an effect on both the vascular and the extravascular components of CNV are discussed.
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16
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Nagaiah G, Remick SC. Combretastatin A4 phosphate: a novel vascular disrupting agent. Future Oncol 2010; 6:1219-28. [DOI: 10.2217/fon.10.90] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Combretastatin A4 phosphate (CA4P) is the lead compound of a relatively new class of agents termed vascular disrupting agents that target existing tumor blood vessels. Rapid tumor blood flow shutdown has been demonstrated in preclinical models and patients by various techniques such as dynamic contrast-enhanced MRI, perfusion computed tomography and PET scans following CA4P infusion. CA4P typically induces rapid tumor necrosis in the center of the tumor and leaves a rim of viable cells in the periphery. In oncology, CA4P does not appear to be that active by itself, but may be more efficacious when combined with chemotherapy, antiangiogenic therapy and radiation therapy. Studies are currently underway, which combine CA4P with antiangiogenic agents. Side effects have included hypertension, tumor pain and occasional cardiovascular toxicity, without any significant myelosuppression or disabling systemic symptoms. The utility of CA4P for conditions other than cancer, which involves neovascularization such as macular degeneration, is also being explored.
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Affiliation(s)
- Govardhanan Nagaiah
- Mary Babb Randolph Cancer Center, West Virginia University School of Medicine, 1801 Health Sciences South, PO Box 9300, Morgantown, WV 26506, USA
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17
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Kanthou C, Tozer GM. Microtubule depolymerizing vascular disrupting agents: novel therapeutic agents for oncology and other pathologies. Int J Exp Pathol 2009; 90:284-94. [PMID: 19563611 DOI: 10.1111/j.1365-2613.2009.00651.x] [Citation(s) in RCA: 160] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Vascular disrupting agents (VDAs) are a relatively new group of 'vascular targeting' agents that exhibit selective activity against established tumour vascular networks, causing severe interruption of tumour blood flow and necrosis to the tumour mass. Microtubule depolymerizing agents form by far the largest group of small molecular weight VDAs many of which, including lead compound disodium combretastatin A-4 3-O-phosphate (CA-4-P), are under clinical development for cancer. Although distinct from the angiogenesis inhibitors, VDAs can also interfere with angiogenesis and therefore constitute a potential group of novel drugs for the treatment of pathological conditions characterized by excessive angiogenesis, in addition to cancer. The endothelial cytoskeleton is the primary cellular target of this family of drugs, and some progress in understanding the molecular and signalling mechanisms associated with their endothelial disrupting activity has been made in the last few years. Susceptibility of tumour vessels to VDA damage is ascribed to their immature pericyte-defective nature, although the exact molecular mechanisms involved have not been clearly defined. Despite causing profound damage to tumours, VDAs fail to halt tumour growth unless used together with conventional treatments. This failure is attributed to resistance mechanisms, primarily associated with cells that remain viable within the tumour rim, and enhanced angiogenesis. The focus is now to understand mechanisms of susceptibility and resistance to identify novel molecular targets and develop strategies that are more effective.
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Affiliation(s)
- Chryso Kanthou
- Cancer Research-UK Tumour Microcirculation Group, Section of Oncology, School of Medicine & Biomedical Sciences, University of Sheffield, Sheffield, UK
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Hubschman JP, Reddy S, Schwartz SD. Age-related macular degeneration: experimental and emerging treatments. Clin Ophthalmol 2009; 3:167-74. [PMID: 19668561 PMCID: PMC2709010 DOI: 10.2147/opth.s5156] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Purpose: This essay reviews the experimental treatments and new imaging modalities that are currently being explored by investigators to help treat patients with age-related macular degeneration (AMD). Design: Interpretative essay. Methods: Literature review and interpretation. Results: Experimental treatments to preserve vision in patients with exudative AMD include blocking vascular endothelial growth factor (VEGF), binding VEGF, and modulating the VEGF receptors. Investigators are also attempting to block signal transduction with receptor tyrosine kinase inhibitors. Experimental treatments for non-exudative AMD include agents that target inflammation, oxidative stress, and implement immune-modulation. The effectiveness of these newer pharmacologic agents has the potential to grow exponentially when used in combination with new and improved imaging modalities that can help identify disease earlier and follow treatment response more precisely. Conclusion: With a better understanding, at the genetic and molecular level, of AMD and the development of superior imaging modalities, investigators are able to offer treatment options that may offer unprecedented visual gains while reducing the need for repetitive treatments.
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Affiliation(s)
- Jean Pierre Hubschman
- Jules Stein Eye Institute, Department of Ophthalmology, University of California, David Geffen School of Medicine, Los Angeles, California, USA
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Ma L, Liu YL, Ma ZZ, Dou HL, Xu JH, Wang JC, Zhang X, Zhang Q. Targeted Treatment of Choroidal Neovascularization Using Integrin-Mediated Sterically Stabilized Liposomes Loaded With Combretastatin A4. J Ocul Pharmacol Ther 2009; 25:195-200. [PMID: 19456253 DOI: 10.1089/jop.2008.0119] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Li Ma
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Yu-Ling Liu
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Zhi-Zhong Ma
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Hong-Liang Dou
- Department of Ophthalmology, Peking University Third Hospital, Beijing, People’s Republic of China
| | - Jun-Hui Xu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, People’s Republic of China
| | - Jian-Cheng Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, People’s Republic of China
| | - Xuan Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, People’s Republic of China
| | - Qiang Zhang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, People’s Republic of China
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Treatment of rodent liver tumor with combretastatin a4 phosphate: noninvasive therapeutic evaluation using multiparametric magnetic resonance imaging in correlation with microangiography and histology. Invest Radiol 2009; 44:44-53. [PMID: 19034028 DOI: 10.1097/rli.0b013e31818e5ace] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVES To document tumoricidal events after intravenous administration of a vascular targeting agent combretastatin A-4-phosphate (CA4P) in rodent liver tumors by using multiparametric magnetic resonance imaging (MRI) in correlation with microangiography and histopathology. MATERIALS AND METHODS Thirty rhabdomyosarcomas of 8 to 14 mm in diameter were obtained 16 days after implantation in liver lobes of 15 rats. Using a 1.5T magnet and a 4-channel wrist coil, T2-weighted imaging (T2WI), pre- and postcontrast T1-weighted imaging (T1WI), diffusion-weighted imaging (DWI), and dynamic susceptibility imaging (DSI) with relative blood volume (rBV) and flow (rBF) maps were acquired at baseline, 1 hour, 6 hours, and 48 hours after iv injection of CA4P at 10 mg/kg and vehicle in 9 treated and 6 control rats, respectively. In vivo data including signal intensity (SI), tumor volume, apparent diffusion coefficient (ADC), rBV, and rBF were correlated with ex vivo microangiographic and histopathologic findings. RESULTS CA4P-treated tumors (n = 18) grew slower than those (n = 12) of controls (P < 0.05), with vascular shutdown evident on CE-T1WI at 1 hour but more prominent at 6 hours. However, enhanced rim occurred in the periphery 48 hours after treatment, indicating neovascularization. ADC map enabled distinction between necrotic and viable tumors. DSI-derived tumoral rBV and rBF decreased significantly at 1 hour through 6 hours and partly recovered at 48 hours. SI-time curve reflected diverse therapeutic responses between tumor and liver. MRI findings were verified by ex vivo techniques. CONCLUSIONS Clinical MRI allowed monitoring of CA4P-related vascular shutdown, necrosis, and neovascularization of liver tumors in rats. Single dose of CA4P seemed insufficient for tumor eradication because of evident peripheral residue and recurrence.
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Takahashi K, Saishin Y, Saishin Y, King AG, Levin R, Campochiaro PA. Suppression and regression of choroidal neovascularization by the multitargeted kinase inhibitor pazopanib. ACTA ACUST UNITED AC 2009; 127:494-9. [PMID: 19365030 DOI: 10.1001/archophthalmol.2009.27] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
OBJECTIVE To investigate pazopanib hydrochloride, a multitargeted kinase inhibitor, for treatment of choroidal neovascularization (CNV). METHODS Choroidal neovascularization was induced in mice by rupture of Bruch membrane with laser photocoagulation. Mice were treated with pazopanib by gavage or periocular injection, and the area of CNV was measured. RESULTS Twice-daily gavage of pazopanib, 100 mg/kg, suppressed the development of CNV by 93%. Treatment of established CNV between days 7 and 14 with 8, 40, or 200 mg/kg per day reduced CNV by 0%, 58%, and 71%, respectively. Substantial regression (40%) of CNV was also achieved after periocular injection of pazopanib. A single oral dose of 4 or 100 mg/kg resulted in an area under the curve from time 0 to the last quantifiable concentration of 129.6 and 752.0 microg x h/mL, respectively. After 7 days of 4, 20, or 100 mg/kg twice a day by gavage, plasma levels were 1300, 4900, and 5800 ng/mL and levels in the retina/choroid were 4800, 28 800, and 38 000 ng/g of tissue. CONCLUSIONS Orally administered pazopanib has good bioavailability to the retina/choroid and strongly suppresses CNV in mice. Treatment with pazopanib after CNV is established causes dose-dependent regression of CNV. CLINICAL RELEVANCE Pazopanib may be useful for treatment of CNV in humans.
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Affiliation(s)
- Kyoichi Takahashi
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA
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22
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Abstract
Anatomy and physiology of the eye makes it a highly protected organ. Designing an effective therapy for ocular diseases, especially for the posterior segment, has been considered as a formidable task. Limitations of topical and intravitreal route of administration have challenged scientists to find alternative mode of administration like periocular routes. Transporter targeted drug delivery has generated a great deal of interest in the field because of its potential to overcome many barriers associated with current therapy. Application of nanotechnology has been very promising in the treatment of a gamut of diseases. In this review, we have briefly discussed several ocular drug delivery systems such as microemulsions, nanosuspensions, nanoparticles, liposomes, niosomes, dendrimers, implants, and hydrogels. Potential for ocular gene therapy has also been described in this article. In near future, a great deal of attention will be paid to develop non-invasive sustained drug release for both anterior and posterior segment eye disorders. A better understanding of nature of ocular diseases, barriers and factors affecting in vivo performance, would greatly drive the development of new delivery systems. Current momentum in the invention of new drug delivery systems hold a promise towards much improved therapies for the treatment of vision threatening disorders.
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23
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Palanki MSS, Akiyama H, Campochiaro P, Cao J, Chow CP, Dellamary L, Doukas J, Fine R, Gritzen C, Hood JD, Hu S, Kachi S, Kang X, Klebansky B, Kousba A, Lohse D, Mak CC, Martin M, McPherson A, Pathak VP, Renick J, Soll R, Umeda N, Yee S, Yokoi K, Zeng B, Zhu H, Noronha G. Development of Prodrug 4-Chloro-3-(5-methyl-3-{[4-(2-pyrrolidin-1-ylethoxy)phenyl]amino}-1,2,4-benzotriazin-7-yl)phenyl Benzoate (TG100801): A Topically Administered Therapeutic Candidate in Clinical Trials for the Treatment of Age-Related Macular Degeneration. J Med Chem 2008; 51:1546-59. [DOI: 10.1021/jm7011276] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Kador PF, Blessing K, Randazzo J, Makita J, Wyman M. Evaluation of the vascular targeting agent combretastatin a-4 prodrug on retinal neovascularization in the galactose-fed dog. J Ocul Pharmacol Ther 2007; 23:132-42. [PMID: 17444801 DOI: 10.1089/jop.2006.0103] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
PURPOSE Combretastatin A-4 (CA-4) is a vascular targeting agent known to rapidly shut off blood flow in new vessels and, as a result, regress neovascularization. In this pilot study, the ability of CA-4 to modify retinal neovascularization, which results in altered retinal vessel blood flow and retinal permeability, was evaluated in aphakic long-term galactose-fed beagles, an animal model that develops diabetes-like retinal neovascularization. METHODS Two (2) groups of aphakic dogs, each group comprised of 4 galactose-fed dogs and 2 age-matched controls dogs, were utilized. Each group initially received the combretastatin A-4-phosphate prodrug (CA-4P) as either sub-Tenon's injections, administered at the corneoscleral junction, or intravitreal injections. Six (6) weeks after this treatment, all dogs also received systemic (intravenous) injections of CA-4P. Retinal vascular changes were monitored at 2-week intervals by fluorescein angiography. RESULTS All galactose-fed dogs demonstrated the presence of retinal neovascular lesions by fluorescein angiograms. Fluorescein leakage or perfusion through neovascular vessels was not altered by either sub-Tenon's, intravitreal, or systemic CA-4P administration. Whereas CA-4P was well tolerated by the healthy eyes of the control animals, its administration to some galactose-fed dogs was associated with corneal edema and increases in intraocular pressure following sub-Tenon's and intraocular injections. CONCLUSIONS Neovascularization in the galactose-fed dog progresses over a period of years, similar to that observed with clinical diabetic retinopathy. The failure of CA-4P to ameliorate neovascularization suggests that chronic, long-term administration may be required to destroy the slowly growing retinal endothelial cells.
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Affiliation(s)
- Peter F Kador
- Laboratory of Ocular Therapeutics, National Eye Institute, National Institutes of Health, Bethesda, MD, USA.
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26
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Lima e Silva R, Shen J, Hackett SF, Kachi S, Akiyama H, Kiuchi K, Yokoi K, Hatara MC, Lauer T, Aslam S, Gong YY, Xiao WH, Khu NH, Thut C, Campochiaro PA. The SDF‐1/CXCR4 ligand/receptor pair is an important contributor to several types of ocular neovascularization. FASEB J 2007; 21:3219-30. [PMID: 17522382 DOI: 10.1096/fj.06-7359com] [Citation(s) in RCA: 106] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Hypoxia causes increased expression of several proteins that have the potential to promote neovascularization. Vascular endothelial growth factor (VEGF) is up-regulated by hypoxia in the retina and plays a central role in the development of several types of ocular neovascularization, but the effects of other hypoxia-regulated proteins are less clear. Stromal-derived factor-1 (SDF-1) and its receptor, CXCR4, have hypoxia response elements in the promoter regions of their genes and are increased in hypoxic liver and heart. In this study, we found that SDF-1 and CXCR4 are increased in hypoxic retina, with SDF-1 localized in glial cells primarily near the surface of the retina and CXCR4 localized in bone marrow-derived cells. Glial cells also expressed CXCR4, which suggested the possibility of autocrine stimulation, but influx of bone marrow-derived cells is the major source of increased levels of CXCR4. High levels of VEGF in the retina in the absence of hypoxia also increased levels of Cxcr4 and Sdf1 mRNA. CXCR4 antagonists reduced influx of bone marrow-derived cells into ischemic retina and strongly suppressed retinal neovascularization, VEGF-induced subretinal neovascularization, and choroidal neovascularization. These data suggest that SDF-1 and CXCR4 contribute to the involvement of bone marrow-derived cells and collaborate with VEGF in the development of several types of ocular neovascularization. They provide new targets for therapeutic intervention that may help to bolster and supplement effects obtained with VEGF antagonists.
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Affiliation(s)
- Raquel Lima e Silva
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, MD 21287-9277, USA
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Abstract
Neovascular age-related macular degeneration (AMD) is becoming an increasing socio-medical problem as the proportion of the aged population is continuously increasing. However, new insights in the pathogenesis of the disease offer the opportunity to develop targeted therapies that attack the disease process more successfully than ever. This review article will focus on summarizing the actual options in the management of neovascular AMD and provide a short overview about recent therapeutic options in clinical and preclinical evaluation. The recent development of anti-VEGF substances for use in clinical routine has markedly improved the prognosis of patients with neovascular AMD. Intravitreal treatment with substances targeting all isotypes of vascular endothelial growth factor (VEGF), for the first time in the history of AMD treatments, results in a significant increase in visual acuity in patients with neovascular AMD. Overall, anti-angiogenic approaches provide vision maintenance in over 90% and substantial improvement in 25-40% of patients. The combination with occlusive therapies like photodynamic therapy (PDT) potentially offers a reduction of re-treatment frequency and long-term maintenance of the treatment benefit. Further developments interacting with various steps in the angiogenic cascade are under clinical or preclinical evaluation and may soon become available. Nevertheless, the growing number of novel therapeutic options will have to provide proof of concept in randomized controlled clinical trials, a major challenge in view of the rapidly evolving field. For those therapies, which are already in clinical use, reasonable diagnostic tools for follow-up need to be developed, as the burden of continuous clinical monitoring of all patients and all indications is significant for patients and doctors. Ultimately, economic issues will be the limiting factor for the clinical availability of different treatment options.
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Affiliation(s)
- Ursula M Schmidt-Erfurth
- Department of Ophthalmology, Medical University of Vienna, Waehringer Guertel 18-20, A 1090 Vienna, Austria.
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Odergren A, Ming Y, Kvanta A. Photodynamic therapy of experimental choroidal neovascularization in the mouse. Curr Eye Res 2006; 31:765-74. [PMID: 16966149 DOI: 10.1080/02713680600865045] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
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.
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Affiliation(s)
- Anne Odergren
- Department of Clinical Neuroscience, Section of Ophthalmology and Vision, Karolinska Institutet, St. Eriks Eye Hospital, Stockholm, Sweden
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29
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Lima e Silva R, Kachi S, Akiyama H, Shen J, Hatara MC, Aslam S, Gong YY, Khu NH, Lauer TW, Hackett SF, Marton LJ, Campochiaro PA. Trans-scleral delivery of polyamine analogs for ocular neovascularization. Exp Eye Res 2006; 83:1260-7. [PMID: 16950258 DOI: 10.1016/j.exer.2006.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2006] [Revised: 05/26/2006] [Accepted: 07/01/2006] [Indexed: 10/24/2022]
Abstract
Periocular injections of the polyamine analog CGC-11144 three times a week causes regression of choroidal neovascularization. This regimen was selected to maximize chances of success for proof of concept, but is not ideal for clinical application. In this study we explored other regimens for periocular delivery of CGC-11144, and 2 other polyamine analogs, CGC-11047 and CGC-11093. A single periocular injection of 200 microg of CGC-11144, 2 mg of CGC-11047, or 1.5 mg of CGC-11093 caused significant suppression and regression of laser-induced choroidal neovascularization. An injection of 2 mg of CGC-11047 or 1.5 mg of CGC-11093 one or two weeks before, but not 3 weeks before, rupture of Bruch's membrane also caused significant suppression. Periocular injection of polyamine analogs also caused strong inhibition of retinal or subretinal neovascularization in mice with oxygen-induced ischemic retinopathy or Rhodopsin promoter/VEGF transgenic mice, respectively. These data suggest that periocular injection of one of 3 different polyamine analogs inhibits retinal or choroidal neovascularization and a single injection provides inhibitory activity for at least 2 to 3 weeks, which could provide the basis for a feasible treatment regimen for clinical trials.
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Affiliation(s)
- Raquel Lima e Silva
- The Departments of Ophthalmology and Neuroscience, The Johns Hopkins University School of Medicine, Maumenee 719, 600 N. Wolfe Street, Baltimore, MD 21287-9277, USA
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Michels S, Schmidt-Erfurth U, Rosenfeld PJ. Promising new treatments for neovascular age-related macular degeneration. Expert Opin Investig Drugs 2006; 15:779-93. [PMID: 16787141 DOI: 10.1517/13543784.15.7.779] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Angiogenesis, the growth of new blood vessels from existing blood vessels, is responsible for vision loss in a variety of ophthalmic diseases. In neovascular age-related macular degeneration (AMD), the leading cause for legal blindness in many industrialised countries, abnormal blood vessels grow in the macula and cause blindness. There are a number of factors important in the angiogenic cascade but VEGF-A has been implicated in recent years as the major factor responsible for neovascular and exudative diseases of the eye. Numerous antiangiogenic drugs are in development but anti-VEGF drugs have shown great promise in treating neovascular AMD and other ocular diseases, and many of these drugs have been adopted from oncology where antiangiogenic therapy is gaining wide acceptance. For the first time in neovascular AMD, anti-VEGF drugs have brought the hope of vision improvement to a significant proportion of patients. This review provides an overview on angiogenic mechanisms, potential antiangiogenic treatment strategies and different antiangiogenic drugs with special focus on neovascular AMD.
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MESH Headings
- Aging
- Angiogenesis Inhibitors/pharmacology
- Angiogenesis Inhibitors/therapeutic use
- Animals
- Antibodies, Monoclonal/administration & dosage
- Antibodies, Monoclonal/economics
- Antibodies, Monoclonal/pharmacology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Monoclonal, Humanized
- Aptamers, Nucleotide/therapeutic use
- Bevacizumab
- Capillary Permeability/drug effects
- Cholestanols/therapeutic use
- Clinical Trials, Phase I as Topic
- Clinical Trials, Phase II as Topic
- Double-Blind Method
- Drug Design
- Drugs, Investigational/pharmacology
- Drugs, Investigational/therapeutic use
- Eye Proteins/physiology
- Humans
- Injections
- Lactates/therapeutic use
- Macular Degeneration/drug therapy
- Macular Degeneration/physiopathology
- Models, Animal
- Multicenter Studies as Topic
- Neovascularization, Pathologic/drug therapy
- Nerve Growth Factors/physiology
- Pigment Epithelium of Eye/metabolism
- Pigment Epithelium of Eye/pathology
- Protein Isoforms/antagonists & inhibitors
- Protein Isoforms/physiology
- RNA Interference
- RNA, Small Interfering/pharmacology
- RNA, Small Interfering/therapeutic use
- Randomized Controlled Trials as Topic
- Serpins/physiology
- Stilbenes/therapeutic use
- Treatment Outcome
- Vascular Endothelial Growth Factor A/antagonists & inhibitors
- Vascular Endothelial Growth Factor A/pharmacology
- Vascular Endothelial Growth Factor A/physiology
- Vascular Endothelial Growth Factor Receptor-2/drug effects
- Vascular Endothelial Growth Factor Receptor-2/physiology
- Vitreous Body
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Affiliation(s)
- Stephan Michels
- Klinik für Augenheilkunde und Optometrie, Medizinische Universität Wien, Währinger Gürtel 18-20, Allgemeines Krankenhaus 8i, 1090 Wien/Vienna, Austria.
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31
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Affiliation(s)
- Jennifer I Lim
- Keck School of Medicine, Department of Ophthalmology, Doheny Eye Institute, University of Southern California, Los Angeles 90033, USA.
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34
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Sun JK, Miller JW. Medical treatment of choroidal neovascularization secondary to age-related macular degeneration. Int Ophthalmol Clin 2005; 45:115-32. [PMID: 16199971 DOI: 10.1097/01.iio.0000177431.66775.09] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- Jennifer K Sun
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, 243 Charles Street, Boston, MA 02114, USA
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35
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Akiyama H, Mohamedali KA, E Silva RL, Kachi S, Shen J, Hatara C, Umeda N, Hackett SF, Aslam S, Krause M, Lai H, Rosenblum MG, Campochiaro PA. Vascular Targeting of Ocular Neovascularization with a Vascular Endothelial Growth Factor121/Gelonin Chimeric Protein. Mol Pharmacol 2005; 68:1543-50. [PMID: 16150930 DOI: 10.1124/mol.105.015628] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tumors provide an extremely abnormal microenvironment that stimulates neovascularization from surrounding vessels and causes altered gene expression within vascular cells. Up-regulation of vascular endothelial growth factor (VEGF) receptors has allowed selective destruction of tumor vessels by administration of a chimeric protein consisting of VEGF121 coupled to the toxin gelonin (VEGF/rGel). We sought to determine whether there is sufficient up-regulation of VEGF receptors in endothelial cells participating in ocular neovascularization to permit a similar strategy. After intravenous injection of 45 mg/kg VEGF/rGel, but not uncoupled recombinant gelonin (rGel), there was immunofluorescent staining for rGel within choroidal neovascularization in mice and regression of the neovascularization occurred, demonstrating successful vascular targeting via the systemic circulation. Intraocular injection of 5 ng of VEGF/rGel also caused significant regression of choroidal neovascularization and regression of retinal neovascularization in two models, transgenic mice with expression of VEGF in photoreceptors and mice with ischemic retinopathy, whereas injection of 5 ng of rGel had no effect. These data suggest that the strategy of vascular targeting can be applied to nonmalignant neovascular diseases and could serve as the basis of a new treatment to reduce established ocular neovascularization.
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Affiliation(s)
- Hideo Akiyama
- Department of Ophthalmology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA
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Young SL, Chaplin DJ. Combretastatin A4 phosphate: background and current clinical status. Expert Opin Investig Drugs 2005; 13:1171-82. [PMID: 15330748 DOI: 10.1517/13543784.13.9.1171] [Citation(s) in RCA: 147] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Combretastatin A4 phosphate (CA4P) represents the lead compound in a group of novel tubulin depolymerising agents being developed as vascular targeting agents (VTAs). VTAs are drugs that induce rapid and selective vascular dysfunction in tumours. CA4P is a water-soluble prodrug of the cis-stilbene CA4 originally isolated from the tree Combretum caffrum. Preclinical studies have shown that CA4P induces blood flow reductions and subsequent tumour cell death in a variety of preclinical models. Moreover, this activity has been linked to its ability to rapidly alter the morphology of immature endothelial cells by disrupting their tubulin cytoskeleton. Phase I clinical trials have established a maximum tolerated dose in the range 60-68 mg/m2 and in addition have established that significant changes to tumour perfusion can be achieved across a wide range of doses. The dose-limiting toxicities include tumour pain, ataxia and cardiovascular changes. The maximum tolerated dose was independent of schedule, indicating the absence of cumulative toxicity. Although unexpected from preclinical studies, some evidence of clinical response was seen using CA4P as a single modality. Based on the Phase I data, combination studies of CA4P with established therapies are in progress and should determine whether the exciting preclinical data obtained when VTAs are used in combination with cytotoxic chemotherapy, radiation, radioimmunotherapy and even antiangiogenic agents, can be translated into man.
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Affiliation(s)
- Scott L Young
- OXiGENE, Inc., 230 Third Avenue, Waltham, MA 02451, USA.
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Comer GM, Ciulla TA, Heier JS, Criswell MH. Future pharmacological treatment options for nonexudative and exudative age-related macular degeneration. Expert Opin Emerg Drugs 2005; 10:119-35. [PMID: 15757408 DOI: 10.1517/14728214.10.1.119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible vision loss in the industrialised world. Within the past decade, researchers have introduced many promising prevention and treatment options in an attempt to minimise the central vision loss imparted from AMD. Based on large-scale, randomised, prospective, placebo-controlled trials, a specially formulated combination of the antioxidants vitamin C, vitamin E, beta-carotene, copper and zinc is the only proven means of AMD prophylaxis. Thermal laser photocoagulation and photodynamic therapy with verteporfin are the only standard treatment options. However, efficacy is limited and treatment is only applicable to a minority of AMD patients. Thus, alternative pharmacological interventions are in all phases of clinical development. Researchers are guardedly optimistic that these advances may change the entire approach to AMD management in the near future. This review article will detail the currently accepted treatment options, as well as describe several of the more promising investigational pharmacological approaches to AMD.
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Affiliation(s)
- Grant M Comer
- Indiana University School of Medicine, Department of Ophthalmology, 702 Rotary Circle, Indianapolis, IN 46202, USA.
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Oshima Y, Oshima S, Nambu H, Kachi S, Takahashi K, Umeda N, Shen J, Dong A, Apte RS, Duh E, Hackett SF, Okoye G, Ishibashi K, Handa J, Melia M, Wiegand S, Yancopoulos G, Zack DJ, Campochiaro PA. Different effects of angiopoietin-2 in different vascular beds: new vessels are most sensitive. FASEB J 2005; 19:963-5. [PMID: 15802489 DOI: 10.1096/fj.04-2209fje] [Citation(s) in RCA: 83] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In this study, we used double transgenic mice with inducible expression of angiopoietin-2 (Ang2) to investigate the role of Ang2 in the retinal and choroidal circulations and in three models of ocular neovascularization (NV). Mice with induced expression of Ang2 ubiquitously, or specifically in the retina, survived and appeared grossly normal. They also had normal-appearing retinal and choroidal circulations, demonstrating that high levels of Ang2 did not induce regression of mature retinal or choroidal vessels. When Ang2 expression was induced soon after birth, there was increased density of the deep capillary bed on postnatal day (P) 11 that returned to normal by P18, the time that retinal vascular development is usually completed. In mice with ischemic retinopathy, induction of Ang2 during the ischemic period resulted in a significant increase in retinal NV, but induction of Ang2 at a later time point when ischemia (and vascular endothelial growth factor [VEGF]) was less, hastened regression of NV. In triple transgenic mice that coexpressed VEGF and Ang2, the increased expression of Ang2 inhibited VEGF-induced NV in the retina. Increased expression of Ang2 also resulted in regression of choroidal neovascularization. These data suggest that ocular neovascularization, but not mature retinal or choroidal vessels, is sensitive to Ang2; a high Ang2/VEGF ratio promotes regression, while high Ang2 in the setting of hypoxia and/or concomitantly high Ang2 and VEGF stimulate neovascularization.
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Affiliation(s)
- Yuji Oshima
- Department of Ophthalmology, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9277, USA
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Vinores SA, Xiao WH, Aslam S, Shen J, Oshima Y, Nambu H, Liu H, Carmeliet P, Campochiaro PA. Implication of the hypoxia response element of the vegf promoter in mouse models of retinal and choroidal neovascularization, but not retinal vascular development. J Cell Physiol 2005; 206:749-58. [PMID: 16245301 DOI: 10.1002/jcp.20525] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Retinal neovascularization (NV) and macular edema, resulting from blood-retinal barrier (BRB) breakdown, are major causes of visual loss in ischemic retinopathies. Choroidal NV (CNV) occurs in diseases of the retinal pigmented epithelium/Bruch's membrane complex and is another extremely prevalent cause of visual loss. We used mice in which the hypoxia response element (HRE) is deleted from the vascular endothelial growth factor (vegf) promoter (Vegf(delta/delta) mice) to explore the role of induction of VEGF through the HRE in these disease processes. Compared to wild type (Vegf+/+) mice with oxygen-induced ischemic retinopathy (OIR) in which vegf mRNA levels were increased and prominent retinal NV and BRB breakdown occurred, Vegf(delta/delta) littermates with OIR failed to increase vegf mRNA levels in the retina and had significantly less retinal NV and BRB breakdown, but showed prominent dilation of some superficial retinal vessels. Vegf(+/delta) littermates with ischemic retinopathy developed comparable retinal NV to Vegf+/+ mice, exhibited intermediate levels of BRB breakdown, and did not show vasodilation. In a mouse model of CNV, due to laser-induced rupture of Bruch's membrane, the area of CNV at Bruch's membrane rupture sites was more than tenfold greater in Vegf+/+ mice than in Vegf(delta/delta) littermates. In contrast to these dramatic differences in pathologic ocular NV, Vegf(delta/delta) mice showed subtle differences in retinal vascular development compared to Vegf+/+ mice; it was slightly delayed, but otherwise normal. These data suggest that induction of VEGF through the HRE in its promoter is critical for retinal and CNV, but not for retinal vascular development.
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Affiliation(s)
- Stanley A Vinores
- Department of Ophthalmology, The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21287-9289, USA.
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Comer GM, Ciulla TA, Criswell MH, Tolentino M. Current and Future Treatment Options for Nonexudative and Exudative Age-Related Macular Degeneration. Drugs Aging 2004; 21:967-92. [PMID: 15631528 DOI: 10.2165/00002512-200421150-00002] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Age-related macular degeneration (AMD) is the leading cause of irreversible visual loss in the industrialised world. Although relatively simple to diagnose through direct visualisation augmented with rapid sequence fluorescein angiography, treatment has presented a far greater challenge because the true aetiology of AMD is largely unknown. Within the past decade, researchers have introduced many new, potentially promising treatment and prevention options in an attempt to minimise the damage imparted from AMD. They capitalise on many of the theoretical and known factors contributing to AMD progression. A high-dose of an orally administered combination of the antioxidants ascorbic acid (vitamin C), tocopherol (vitamin E) and beta-carotene, in addition to copper and zinc, is the only widely accepted preventive therapy. Thermal laser photocoagulation and verteporfin photodynamic therapy are the only standard treatment options available based on large scale, randomised, prospective, placebo-controlled trials; however, efficacy is limited and only a minority of patients who present with AMD are eligible for these treatments. Many other preventive and treatment options are in all phases of clinical studies and expected to change the entire approach to AMD management in the near future. For example, alternative antioxidants, drusen ablation, apheresis and HMG-CoA reductase inhibitors have shown promise in some studies by preventing or slowing the progression of certain forms of AMD. In addition, alternative photodynamic therapies, low-intensity laser, antiangiogenic medications, radiation treatment and surgery have demonstrated the ability, albeit to differing degrees, to inhibit or possibly even reverse the severe vision loss often associated with AMD characterised by choroidal neovascularisation.
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Affiliation(s)
- Grant M Comer
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Indiana, USA
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