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VEGF Gene Therapy Improves Anastomotic Healing in the Gastrointestinal Tract: Applications in Esophageal Surgery
Kristian Enestvedt*1, Shelley R. Winn1, Brian S. Diggs1, Luke Hosack1, Barry Uchida2, Robert W. O'Rourke1, Blair a. Jobe1
1Department of Surgery, Oregon Health and Science University, Portland, OR; 2Dotter Institue, Department of Interventional Radiology, Oregon Health and Science University, Portland, OR
Background: Anastomotic leak related to ischemia is a source of significant morbidity and mortality. The aim of this study was to utilize VEGF gene therapy for the purpose of up-regulating angiogenesis, increasing anastomotic strength, and ultimately preventing dehiscence.
Methods: An opossum esophagogastrostomy model was employed. The vascular endothelial growth factor (VEGF165) gene was incorporated into a circular recombinant plasmid. The plasmid was complexed with a non-viral synthetic vector, Jet-PEI. Control animals received plasmid devoid of VEGF165 (n=6). The experimental group received VEGF165 plasmid (n=5). After esophagogastrectomy and gastric tubularization, plasmid was injected into the submucosa of the neoesophagus at the anastomotic site. Conduit arteriography was performed before and 10 days after injection. Euthanasia occurred on post-injection day 10 and the anastomosis was removed en bloc. Blood flow was measured with laser-Doppler prior to euthanasia. Ex vivo anastomotic bursting pressure was performed. Tissue samples were procured for RNA extraction and Factor VIII staining. Microvessel counts were obtained by 2 blinded observers. VEGF mRNA transcript levels were measured with quantitative RT-PCR using custom primers.
Results: There were no deaths in either group. There was one leak in the control group. Experimental animals demonstrated significantly increased bursting pressure and neovascularization compared to controls (Table). In addition, there was a strongly positive correlation between the number of microvessels and bursting pressure (r=0.808, p=0.015, Pearson’s). On angiographic examination, treated animals demonstrated more neovascularization compared to controls. RT-PCR demonstrated a 2.1 fold increase in VEGF mRNA tissue transcript levels in treated animals compared to controls (p=0.05, t-test).
Discussion: This first description of successful gene therapy in the gastrointestinal tract using VEGF165 transfection demonstrates improved anastomotic healing in a clinically relevant model which may directly translate to human application.
| Groups | Microvessels (#/hpf) (p=0.032, t-test) | Blood Flow at Harvest (ml/min/100gm) (p=0.191, t-test) | Bursting Pressure (mm Hg) (p=0.021, t-test) |
| Control | 20.33 | 4.18 | 86.73 |
| Experimental | 33.87 | 6.68 | 104.25 |
*all numbers are mean values
