Use of partial liver grafting techniques has increased rapidly in recent years; however, small-for-size grafts remain a major problem since many fail when used as donor organs. Therefore, the relationship between graft size and graft failure needs to be understood. The goals of this project are to elucidate mechanisms involved in the failure of small-for-size grafts and to develop strategies to prevent it. We will use reduced-size liver transplantation of decreasing graft weight/standard liver weight (GW/SLW) in rats to test the unique hypothesis that free radicals increase in small-for-size grafts leading to graft failure. Our goal in Aim 1 will be to investigate the effects of graft volume, manipulation during harvest, and cold storage on survival of partial liver grafts. The time course of survival, transaminase release, and liver function will be observed in vivo after transplantation. Liver function will also be evaluated in isolated-perfusion of grafts after transplantation. ATP/ADP/AMP contents and oxygen uptake will be determined to evaluate mitochondrial function. Survival and non-survival conditions will be established, validating it as a useful model for mechanistic studies. Next, we will test the hypothesis that free radicals are produced in small-for-size grafts leading to injury. Effects of graft volume, cold storage, and manipulation during harvest on free radical production, 4-hydroxynonenal, and GSH after transplantation of partial grafts will be determined in Aim 2. We expect free radical production will be increased to a greater extent in small-for-size liver grafts, and cold storage and manipulation will further enhance this effect. In addition, we will identify cellular sources of free radicals using fluorescent probes and intravital multiphoton microscopy.
In Aim 3, the effects of antioxidant therapies (polyphenols, Carolina Rinse solution, and gene delivery of superoxide dismutase) on survival of small-for-size grafts will be evaluated under non-survival conditions determined in Aim 1, and effects on transaminase, liver function and free radical production will be compared. We expect that antioxidant therapies will prevent free radical production and reduce graft failure of small-for-size grafts and to identify the most effective therapy. Finally, the effects of antioxidant therapies on liver regeneration will be evaluated in Aim 4. Incorporation of 5-bromo-2'-deoxyuridine and factors regulating regeneration (cytokines, transcription factors, growth factors, and energy supply) will be evaluated. Taken together, we expect that these studies will provide unequivocal evidence supporting a role for free radicals in primary graft failure of small-for-size grafts. This work will develop mechanism-based strategies to increase the use and improve the outcome of partial livers for transplantation in the clinic.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Scientist Development Award - Research & Training (K01)
Project #
5K01DK062089-03
Application #
6752765
Study Section
Diabetes, Endocrinology and Metabolic Diseases B Subcommittee (DDK)
Program Officer
Podskalny, Judith M,
Project Start
2002-08-01
Project End
2005-06-30
Budget Start
2004-07-01
Budget End
2005-06-30
Support Year
3
Fiscal Year
2004
Total Cost
$94,428
Indirect Cost
Name
University of North Carolina Chapel Hill
Department
Pharmacology
Type
Schools of Medicine
DUNS #
608195277
City
Chapel Hill
State
NC
Country
United States
Zip Code
27599
Rehman, Hasibur; Connor, Henry D; Ramshesh, Venkat K et al. (2008) Ischemic preconditioning prevents free radical production and mitochondrial depolarization in small-for-size rat liver grafts. Transplantation 85:1322-31
Zhong, Z; Theruvath, T P; Currin, R T et al. (2007) NIM811, a mitochondrial permeability transition inhibitor, prevents mitochondrial depolarization in small-for-size rat liver grafts. Am J Transplant 7:1103-11
Zhong, Zhi; Connor, Henry D; Li, Xiangli et al. (2006) Reduction of ciclosporin and tacrolimus nephrotoxicity by plant polyphenols. J Pharm Pharmacol 58:1533-43
Zhong, Zhi; Schwabe, Robert F; Kai, Yoichiro et al. (2006) Liver regeneration is suppressed in small-for-size liver grafts after transplantation: involvement of c-Jun N-terminal kinase, cyclin D1, and defective energy supply. Transplantation 82:241-50
Zhong, Zhi; Connor, Henry D; Froh, Mattias et al. (2005) Free radical-dependent dysfunction of small-for-size rat liver grafts: prevention by plant polyphenols. Gastroenterology 129:652-64
Zhong, Zhi; Lemasters, John J (2004) Role of free radicals in failure of fatty liver grafts caused by ethanol. Alcohol 34:49-58
Zhong, Zhi; Connor, Henry D; Froh, Mattias et al. (2004) Polyphenols from Camellia sinenesis prevent primary graft failure after transplantation of ethanol-induced fatty livers from rats. Free Radic Biol Med 36:1248-58
Zhong, Zhi; Froh, Matthias; Lehnert, Mark et al. (2003) Polyphenols from Camellia sinenesis attenuate experimental cholestasis-induced liver fibrosis in rats. Am J Physiol Gastrointest Liver Physiol 285:G1004-13