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: Impaired hepatic microcirculation in the steatotic liver has been identified as a considerable factor for increased vulnerability after ischemia/reperfusion (I/R). Changes in regulation and synthesis of vasoactive mediators, such as nitric oxide (NO) and endothelin (ET-1), may result in functional impairment of postischemic sinusoidal perfusion. The aim of the current study was to assess the impact of I/R injury on postischemic gene expression of NO and ET-1 in steatotic livers. Male Sprague-Dawley rats with or without hepatic steatosis (induced by carbon tetrachloride treatment) were subjected to normothermic I/R injury. Steady-state mRNA levels were assessed using RT-PCR to study the expression of genes encoding ET-1, NO synthase (endothelial cell NO synthase and inducible NO synthase, iNOS). Immunohistochemistry was performed for detection of iNOS. I/R injury was followed by increased iNOS gene expression (RT-PCR/immunohistochemistry) in animals with hepatic steatosis, predominately in hepatocytes with fatty degeneration. A mild increase in mRNA levels for ET-1 was found in steatotic rat livers. I/R induced a further increase in ET-1 gene expression in some but not all reperfused steatotic livers. We show an enhanced gene expression of iNOS in postischemic steatotic rat livers. Hepatocytes with fatty degeneration appear to be the major source for NO generation. Furthermore, I/R may also induce ET-1 gene expression. Dysregulation of sinusoidal perfusion by NO and ET-1 is therefore likely to contribute to I/R injury of the steatotic liver.European Surgical Research 02/2007; 39(5):303-11. · 0.75 Impact Factor
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ABSTRACT: The use of non-heart-beating donors (NHBD) helps us to deal with the problem of the organ shortage. In addition to difficulties with legal and ethical acceptability, there are concerns regarding medical safety, which prevent the widespread use of these donors. To make optimum use of this potential organ supply, the ischemic injury that occurs after a period of warm ischemia needs to be reversed. To minimize the warm ischemia time, once the subject is declared dead, most centers commence in situ cold perfusion via a femoral access or a rapid aortic cannulation. This usually occurs within minutes of arriving at the emergency department, before the next of kin have been notified of the patient's death. The European experience of kidney transplantation from NHBD shows promising results. The long-term outcomes are similar to HBD kidneys notwithstanding a higher rate of delayed graft function, which seems not to affect the long-term survival of these kidneys. In summary, NHBD may have an important impact on the large discrepancy that exists between the organ supply and the demand. Current data suggest that the results may be further improved by better patient selection and retrieval team organization.Transplantation Proceedings 10/2004; 36(7):1891-3. · 0.95 Impact Factor
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ABSTRACT: The balance between nitric oxide (NO) and endothelin-1 (ET-1) production is essential to the vascular function that controls organ perfusion. Elevated ET-1 levels in the peritubular capillary network following renal transplantation may be associated with renal allograft rejection. Administration of a nitric oxide donor during the preischemic period has been shown to protect kidney against ischemia-reperfusion injury, but the mechanism underlying this therapeutic benefit remains incompletely understood. We hypothesized that early administration of the NO donor sodium nitroprusside (SNP) may suppress ET-1, thereby improving renal function in an ischemia/reperfusion injury. Sprague-Dawley rats were subjected to 60 minutes of renal warm ischemia and contralateral nephrectomy. Renal biopsies were performed prior to ischemia and reperfusion, and at 1 hour and 48 hours after reperfusion. The animals were divided into four groups: sham group without warm ischemia; early SNP group (SNP given before ischemia); late SNP group (SNP given before reperfusion); and ischemic control. ET-1 expression was assessed by semiquantitative analysis with immunohistochemical stain using ET-1 monoclonal antibody and hematoxylin-eosin staining. Serum creatinine was measured at 48 hours after reperfusion. There were significant improvements in all parameters of the early compared with the late SNP group and the ischemic control, but there was no difference between the late SNP group and the ischemic control. These data suggest that early administration of SNP in renal ischemia-reperfusion improves renal function by suppressing ET-1 expression.Transplantation Proceedings 10/2004; 36(7):1943-5. · 0.95 Impact Factor