Hemodialysis vascular access dysfunction is the single most important cause of hospitalization in hemodialysis patients and is responsible for a very significant morbidity within this patient population. Thrombosis of PTFE dialysis grafts due to venous stenosis as a result of venous neointimal hyperplasia (VNH), is the most common cause of vascular access dysfunction. Surprisingly, there are currently no effective therapeutic interventions for VNH despite its clinical importance. Analysis of cell types and cytokines in dialysis patients with venous stenosis due to VNH and data from a validated pig model of venous neointimal hyperplasia, that is very similar to the human lesion have been described. These studies clearly demonstrate that smooth muscle cell (SMC) proliferation and the formation of microvessels (endothelial cell proliferation), within the neointima and adventitia are critical features of VNH. In addition, it is likely that PTFE dialysis grafts are the ideal clinical model to test out novel local interventions, in view of their superficial location and easy accessibility. It is therefore proposed to test out novel locally delivered anti-proliferative therapies in a validated pig model of VNH, in the hope of being able to rapidly translate positive findings into a clinical setting of great need. Three local interventions will be evaluated in this proposal for their anti-proliferative effects. (a) External radiation therapy: Initial studies in the pig model, have demonstrated a reduction in VNH (albeit less than in models of coronary angioplasty), with a single dose of l6Gy. We now plan to optimize a radiation schedule for VNH by testing out 3 different radiation regimens (b) Local polymeric delivery of paclitaxel and TNP-470: A local polymeric delivery system comprising ethylene-vinyl-acetate matrices loaded with paclitaxel and TNP-470 (both are potent anti-proliferative agents) will be developed and tested in vitro against SMC and endothelial cells. Polymeric matrices will then be wrapped around the graft vein anastomosis in a perivascular configuration in an attempt to reduce luminal stenosis and VNH. (c) Combination radiation therapy and local anti-proliferative therapy: The most effective radiation and anti-proliferative regimens from (a) and (b) will be combined in this final analysis, in the hope of achieving a synergistic effect. We believe that the results from this study could transform the clinical care of hemodialysis patients and at the same time result in the successful clinical application of local therapy for the treatment of neointimal hyperplasia.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK061689-03
Application #
6784524
Study Section
General Medicine B Study Section (GMB)
Program Officer
Eggers, Paul Wayne
Project Start
2002-08-05
Project End
2006-05-31
Budget Start
2004-06-01
Budget End
2005-05-31
Support Year
3
Fiscal Year
2004
Total Cost
$294,897
Indirect Cost
Name
University of Cincinnati
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
041064767
City
Cincinnati
State
OH
Country
United States
Zip Code
45221
Roy-Chaudhury, Prabir; Wang, Yang; Krishnamoorthy, Mahesh et al. (2009) Cellular phenotypes in human stenotic lesions from haemodialysis vascular access. Nephrol Dial Transplant 24:2786-91
Wang, Yang; Krishnamoorthy, Mahesh; Banerjee, Rupak et al. (2008) Venous stenosis in a pig arteriovenous fistula model--anatomy, mechanisms and cellular phenotypes. Nephrol Dial Transplant 23:525-33
Roy-Chaudhury, Prabir; Arend, Lois; Zhang, Jianhua et al. (2007) Neointimal hyperplasia in early arteriovenous fistula failure. Am J Kidney Dis 50:782-90
Asif, Arif; Ravani, Pietro; Roy-Chaudhury, Prabir et al. (2007) Vascular mapping techniques: advantages and disadvantages. J Nephrol 20:299-303
Ravani, Pietro; Spergel, Lawrence M; Asif, Arif et al. (2007) Clinical epidemiology of arteriovenous fistula in 2007. J Nephrol 20:141-9
Spergel, Lawrence M; Ravani, Pietro; Asif, Arif et al. (2007) Autogenous arteriovenous fistula options. J Nephrol 20:288-98
Roy-Chaudhury, Prabir; Spergel, Lawrence M; Besarab, Anatole et al. (2007) Biology of arteriovenous fistula failure. J Nephrol 20:150-63
Zhang, J; Melhem, M; Kassing, W et al. (2007) In vitro paclitaxel and radiation effects on the cell types responsible for vascular stenosis: a preliminary analysis. Blood Purif 25:155-60
Kelly, Burnett; Melhem, Murad; Zhang, Jianhua et al. (2006) Perivascular paclitaxel wraps block arteriovenous graft stenosis in a pig model. Nephrol Dial Transplant 21:2425-31
Roy-Chaudhury, Prabir; Sukhatme, Vikas P; Cheung, Alfred K (2006) Hemodialysis vascular access dysfunction: a cellular and molecular viewpoint. J Am Soc Nephrol 17:1112-27

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