Slide 1Use of Vascular Endothelial Growth Factor (VEGF) as a Treatment for End Stage Coronary Artery Disease (CAD)Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13Slide 14Slide 15Slide 16Slide 17Why it works?Problems:ReferencesHeart DiseaseHeart DiseaseIn 1995:481,000 deaths related to Coronary Artery Disease (CAD)1,100,000 new or recurrent cases of CADEstimated that 7.2 million people experienced angina to some degreeTreatment434,000 angioplasties performed573,000 Bypasses performed60,000-100,000 patients not good candidates for bypass/angioplasty(Possibly up to 250,000 patients a year)Use of Vascular Endothelial Growth Factor (VEGF) as a Treatment for End Stage Coronary Artery Disease (CAD)By: Jeremy GillisSenior…Biochemistry and Molecular BiologyCurrent Treatments for CADCurrent Treatments for CADPercutaneous Transluminal Coronary Angioplasty or PTCA (434,000)Coronary Artery Bypass Graft (CABG) “cabbage” (573,000)Vascular Stents (wire props for an artery)Rotational Atherectomy (much like a drill)Problems with Current TreatmentsProblems with Current Treatments Restenosis  Graft disease Arterial puncture Coronary thrombosisHow can we help people who don’t respond well or are not good candidates for conventional treatments?It is thought that VEGF is involved in It is thought that VEGF is involved in AngiogenesisAngiogenesisAngiogenesis: the formation of new blood vessels (collaterals) from existing microvesselsContributes to the preservation of ischemic tissue and myocardial pump function after myocardial infarctionImportant in: Embryogenesis (called vasculogenesis) Wound healing  Tumor growth and metastasization Rheumatoid arthritis Ischemic heart disease Ischemic peripheral vascular diseaseInducing AngiogenesisInducing Angiogenesis1. Need a stimulusHypoxic tissue, Ischemic tissue, Mechanically damaged tissue2. Need expression of angiogenic molecules to initiate angiogenesisVEGF, FGF, TGF, PDGF3. Need angiogenesis to occur1. Proliferation and migration of endothelial cells from the microvasculature2. Controlled expression of proteolytic enzymes3. Breakdown and reassembly of extracellular matrix4. Morphogenic process of endothelial tube formationMechanism of Angiogenesis not completely knownWhy use VEGF to Promote Angiogenesis?Why use VEGF to Promote Angiogenesis?VEGF (vascular endothelial growth factor)Specific for only endothelial cellsMay inhibit smooth muscle growth…reduce restenosisFGF (fibroblast growth factor)Associated with tumor angiogenesisCan stimulate growth in other cells besides endothelial cellsNot as specific as VEGFTGF- (transforming growth factor ß) Indirect angiogenesis effectPossibly induces VEGF expression (Protein Kinase C pathway)PDGF (platelet derived growth factor)Not well characterized in angiogenesisOther VEGF CharacteristicsOther VEGF CharacteristicsVEGF expressed by Macrophages, fibroblasts, smooth muscle cells, endothelial cells (all are present in the heart)Action is direct because of the exclusive specificity for receptors (flt-1 and flk-1) Receptors only found on endothelial cells Causes activation of many other genes involved in angiogenic responseHow to Deliver VEGFHow to Deliver VEGFProtein Therapy Direct injection of protein Time delay delivery Local intercoronary bolusGene TherapyAdenovirus vector Excellent specificity for endothelial cells Extended expression of VEGFDirect gene transfer Involves direct injection of eukaryotic plasmid DNA containing VEGF cDNAShould VEGF administration prove effective, it is likely that VEGF/VEGF DNA will be delivered on a catheter platformCase StudiesCase StudiesInjection of naked VEGF cDNA contained in an Eukaryotic Expression VectorJeffery Isner et al. St. Elizabeth’s Medical CenterPhase I clinical trial…designed to assess safety and bioactivity of treatment methodsLimited sample…only 5 patients involvedPrior Bypass and/or angioplastyClass 3-4 AnginaNo longer respond to additional treatmentAgeLifestyle Before Treatment Lifestyle After Treatment67 Angina from Mild activity〈 Angina virtually gone〈 Able to resume swimming〈 Nitroglycerin (NTG) no longer needed69 Angina after walking 10 yards〈 30 days post needed very little NTG〈 60 days post could exercise for 30minutes on a stationary bike53 Angina after walking 50 yards〈 60 days post could walk ? mile〈 Claims to have felt beneficial effectsafter only two weeks71 Angina from walking 100 yards〈 30 days NTG use decreased dramatically〈 Returned to work part time59 Daily Angina〈 30 days later could walk up to ? milewithout pain〈 Less need for supplemental oxygen〈 2 episodes of angina/monthResultsResultsAlso notable:Also notable:Nitroglycerin usage dropped from 7.7 pills per day to 1.4 per day for the group (60 days post)Effective biological outcomes despite low transfection ratesBecause of the condition of the patients in the study, the improvements to health were not likely random eventsAll 5 patients had remarkable gains in quality of life post procedureAnimal Data:Animal Data: Charles Mack et al. New York Hospital-Cornell Medical CenterAdministration VEGF gene through Adenovirus mediated gene therapyPreclinical work to determine efficacy in an animal model of ischemiaModel:Model:Pig with a constrictor band around circumflex artery to induce myocardial infarction and ischemiaEventually results in complete occlusion of circumflex arteryVector:Vector:Adenovirus vector in E1a-, partial E1b-, and partial E3- mutations (makes them replication deficient)Adenovirus used because of the natural selectivity for endothelial cellsMinimal inflammation detected in animals 4 weeks post therapy In vivo conformation of expression confirmed by ELISA 3 days after injectionResultsResultsTreatment Resulted in significantly reduced ischemic area (area of oxygen starved tissue) and Ischemic maximum (severity of ischemia) in treated animals Strength of heartbeat returned in treated animals more than untreated animalsMore vessels visible angiographically in treated animals vs. untreated animals Treated animals seemed to route around the occlusion as demonstrated by the filling of branching arteriesWhy it works?Why it works?Placebo effect?VEGF stimulates growth of “collateral” vessels?Microvessel growth due to