Relationship between ischemia/reperfusion injury and the stimulus of fibrogenesis in an experimental model: comparison among different preservation solutions.

BACKGROUND AND AIMS: 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. MATERIALS AND METHODS: 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-ß1 and angiotensin II AT1 receptor. RESULTS: 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-ß1 or AT1 receptor. CONCLUSION: 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.

Fructose 1-6 bisphosphate versus University of Wisconsin solution for rat liver preservation: does FBP prevent early mitochondrial injury?

BACKGROUND: Fructose 1,6-biphosphate (FBP) has been shown to exert therapeutic effects in models of ischemia-reperfusion in organs other than the liver. This study compared FBP and University of Wisconsin (UW) solution during cold storage and reperfusion, among mitochondria of adult male Wistar rat livers. METHODS: Adult male Wistar rats were assigned to two groups according to the preservation solution used; UW or FBP Aspartate transaminase (AST), alanine transferase (ALT); and lactic dehydrogenase (LDH) were measured in samples of the storage solution obtained at 2, 4 and 6 hours of preservation. After 6 hours of cold storage, we reperfused the liver, taking blood samples to measure AST, ALT, LDH, and throbarbituric acid reactive substances (TBARS). Hepatic fragments were processed for histologic analysis; for determinations of TBARS, catalase, and nitric oxide as well as for mitochondrial evaluation by infrared spectroscopy. RESULTS: During cold preservation, levels of AST and LDH in the storage solution were lower among the FBP group, but after reperfusion, serum levels of AST, ALT, and LDH were higher in this group, as was catalase activity. TBARS and nitric oxide were comparable between the groups. In the UW group there was a higher amide I/amide II ratio than in the FBP group, suggesting an abnormal protein structure of the mitochondrial membrane. No signs of preservation injury were observed in any liver biopsy, but sinusoidal congestion was present in livers preserved with FBP. CONCLUSION: FBP showed a protective effect for preservation during cold storage seeming to protect the mitochondrial membrane although it did not prevent reperfusion injury.