Protective effects of L-arginine against ischemia-reperfusion injury in non-heart beating rat liver graft.
ABSTRACT Although the use of non-heart beating donors (NHBDs) could bridge the widening gap between organ demand and supply, its application to liver transplantation is limited due to the high incidence of primary graft loss. Prevention of liver injury in NHBDs will benefit the results of transplantation. This study was conducted to evaluate the protective effects of L-arginine on liver grafts from NHBDs.
One hundred and four Wistar rats were randomly divided into 7 groups: normal control (n=8), controls 1, 2 and 3 (C1, C2, C3, n=16), and experimental 1, 2 and 3 (E(1), E(2), E(3), n=16). For groups C(1) and E(1), C(2) and E(2), and C(3) and E(3), the warm ischemia time was 0, 30, and 45 minutes, respectively. Liver grafts were flushed with and preserved in 4 degree centigrade Euro-collins solution containing 1 mmol/L L-arginine for 1 hour in each experimental group. Recipients of each experimental group were injected with L-arginine (10 mg/kg body weight) by tail vein 10 minutes before portal vein reperfusion. Donors and recipients of each experimental control group were treated with normal saline. Then transplantation was performed. At 1, 3, and 24 hours after portal vein reperfusion, blood samples were obtained to determine the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), nitric oxide (NO) and plasma endothelin (ET). At 3 hours after portal vein reperfusion, grafts samples were fixed in 2.5% glutaraldehyde for electron microscopic observation.
At 1 hour after portal vein reperfusion, the levels of NO in groups E(1), E(2), E(3) and C(1), C(2), C(3) were lower, while the levels of plasma ET, serum ALT and AST were higher than those in the normal control group (P<0.05). At 1, 3, and 24 hours, the levels of NO in groups E(1), E(2), E(3) were higher, while the levels of plasma ET, serum ALT and AST were lower than those in the corresponding control groups (C(1), C(2), C(3) (P<0.05). The levels of NO in groups C(2) and C(3) were lower than in group C1 (P<0.05), and the level of NO in group C(3) was lower than in group C(2) (P<0.05). At 1, 3 and 24 hours, the levels of plasma ET, serum ALT, and AST in groups E1, E2, E3 were lower than those in the corresponding control groups (C(1), C(2), C(3)) (P<0.05). The levels of plasma ET, serum ALT, and AST were lower in group C(3) than in groups C(1) and C(2) (P<0.05). Pathological changes in groups E(1), E(2), E(3) were milder than those in the corresponding experimental control groups (C(1), C(2), C(3)).
The imbalance between NO and ET plays an important role in the development of ischemia-reperfusion injury of liver grafts from NHBDs. L-arginine can attenuate injury in liver grafts from NHBDs by improving the balance between NO and ET.
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ABSTRACT: Living donor liver transplantation has been widely accepted as the treatment of choice for end-stage liver disease. Large amounts of nitric oxide generated by inducible nitric oxide synthase (iNOS) have been shown to play an important role in many inflammatory and immune reactions, but expression of iNOS in small-for-size liver transplantation is unknown. The aims of this study were to determine the time course of iNOS mRNA and protein as well as the redox state of liver biopsies in a rat model of small-for-size liver transplantation. Male Sprague-Dawley rats were divided into a control group, a warm ischemia-reperfusion (IR) group, and a small-for-size liver graft group. Real-time RT-PCR and Western blotting were used to characterize the time course of the expression of iNOS mRNA and protein, respectively. Malondialdehyde (MDA) and superoxide dismutase (SOD) were used as markers to characterize the redox state of liver tissues, and the time courses of MDA and SOD levels were also measured. The expression of iNOS mRNA and protein levels in the warm IR and small-for-size graft groups both significantly increased after reperfusion, and peaked at 3 hours. Moreover, the increase in MDA was accompanied by increased iNOS in the period of 1-24 hours after reperfusion. The MDA levels in the warm IR and small-for-size graft groups significantly increased after reperfusion, peaked at 3 hours, and decreased thereafter. The direction of change in SOD was opposite that of the change in MDA. The expression of iNOS mRNA and protein is activated after reperfusion both in hepatic warm IR injury and small-for-size liver graft. Furthermore, the results of this study suggest that iNOS contributes to the damage in warm IR injury and small-for-size grafts via free oxygen radicals.Hepatobiliary & pancreatic diseases international: HBPD INT 05/2009; 8(2):146-51.
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ABSTRACT: Orthotopic liver transplantation (OLT) has been the standard treatment for end-stage acute and chronic liver disease. Ischemia-reperfusion (I/R) injury is one of the major causes of poor graft function early after OLT, and adversely influencing graft and patient survivals. It is unknown whether I/R injury influences liver fibrogenesis. Livers from 25 adult male Wistar rats were randomly assigned into 5 experimental groups according to the preservation solution: saline solution (SS); University of Wisconsin (UW) solution; Fructose 1, 6-biphosphate (FBP); S-Nitroso-N-Acetylcysteine (SNAC): or UW+SNAC (SNAC+UW). Aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactic dehydrogenase (LDH) were determined in preservation solution samples at 2, 4, and 6 hours. After 6 hours of cold ischemia, ex situ reperfusion was applied to the liver for 15 minutes. Serum AST, ALT, LDH, and renin levels were determined. Fresh liver slices were processed for histological studies, determination of thiobarbituric acid reactive substances, catalase, and glutathione, and expression of TGF-β1 and angiotensin II AT1 receptor. AST was significantly lower during cold storage with UW than with the older media (P=.001); ALT was lower in the FBP group (P=.023) and LDH was lower in the FBP and SNAC groups (P=.007). After reperfusion, serum AST, ALT, LDH, and TBARS showed no significant differences among the groups. Catalase was significantly lower in the SS and FBP groups (P=.008 and P=.006, respectively). Compared with UW, glutathione concentrations were significantly higher in SS, FBP, and SNAC 200 (P=.004). Renin levels were significantly lower in the FBP group (P=.022). No histological signs of preservation injury were observed in the hepatic sample. No expressions were detected of TGF-β1 or AT1 receptor. In this experimental model of early reperfusion injury, preservation changes related to higher levels of renin, which suggest its role in fibrogenesis. FBP was associated with lower renin levels than other solutions including UW.Transplantation Proceedings 12/2011; 43(10):3634-7. DOI:10.1016/j.transproceed.2011.08.114
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ABSTRACT: The last decade saw increased organ donation activity from donors after cardiac death (DCD). This contributed to a significant proportion of transplant activity. Despite certain drawbacks, liver transplantation from DCD donors continues to supplement the donor pool on the backdrop of a severe organ shortage. Understanding the pathophysiology has provided the basis for modulation of DCD organs that has been proven to be effective outside liver transplantation but remains experimental in liver transplantation models. Research continues on how best to further increase the utility of DCD grafts. Most of the work has been carried out exploring the use of organ preservation using machine assisted perfusion. Both ex-situ and in-situ organ perfusion systems are tested in the liver transplantation setting with promising results. Additional techniques involved pharmacological manipulation of the donor, graft and the recipient. Ethical barriers and end-of-life care pathways are obstacles to widespread clinical application of some of the recent advances to practice. It is likely that some of the DCD offers are in fact probably "prematurely" offered without ideal donor management or even prior to brain death being established. The absolute benefits of DCD exist only if this form of donation supplements the existing deceased donor pool; hence, it is worthwhile revisiting organ donation process enabling us to identify counter remedial measures.11/2011; 3(11):167-76. DOI:10.4240/wjgs.v3.i11.167