Mechanism of primary graft non-function in a rat model for fatty liver transplantation

Comparison of overfed Xupu and Landes geese in performance, fatty acid composition, enzymes and gene expression related to lipid metabolism

Objective

The aim of this study was to compare overfeeding performance, fatty acid composition, blood chemistry, enzymes and genes expression overfed Xupu and Landes geese.

Methods

Sixty male Xupu geese (80 d) and Landes geese (80 d) were selected. After a period of one-week of pre-overfeeding, Xupu and Landes geese were overfed three meals of 550 and 350 g/d, respectively, of a high-carbohydrate diet in the first week of the overfeeding period. The next week, geese were given four meals of 1,200 and 850 g/d, respectively, over 8 to 14 d. Finally, geese were given five meals of 1,600 and 1,350 g/d, respectively, for the last two weeks.

Results

After overfeeding for 28 d: Compared with Landes geese, Xupu geese liver weight and liver-to-body weight ratio decreased (p<0.05), while final weight, slaughter weight, total weight gain, abdominal fat weight, and feed-to-liver weight ratio increased (p<0.05). The levels of elaidic acid (C18:1t9), oleic acid (C18:1n-9), eicosenoic acid, and arachidonic acid in the liver of Xupu geese significantly increased (p<0.05), and the levels of myristic acid and stearic acid significantly decreased (p<0.05), while methyleicosanoate acid significantly increased (p<0.05). Xupu geese had higher plasma concentrations of triglyceride and very low density lipoprotein cholesterol (p<0.05), and decreased activities of alanine aminotransferase, aspartate aminotransferase, and lipase (LPS) (p<0.05). Landes geese had higher LPS activity (p<0.05), but lower cholinesterase activity (p<0.05) when compared with Xupu geese. The mRNA expression levels of fatty acid dehydrogenase (FADS) gene, elongase of long-chain fatty acid 1 (ELOVL1) gene, ELOVL5, and acyl-Co A: cholesterol acyltransferase 2 (ACAT2) gene were significantly upregulated (p<0.05) in Landes goose when compared with Xupu geese.

Conclusion

This study demonstrates that the liver production performance of Landes geese was better than that of Xupu geese to some extent, which may be closely related to LPS activity, as well as the expression of FADS, ELOVL1, ELOVL5, and ACAT2.

Body surface area index predicts outcome in orthotopic liver transplantation

BACKGROUND/PURPOSE

In living donor liver transplantation (LDLT), matching of liver volume between donor and recipient is critical to the success of the procedure; mismatch can result in 'small- or large-for-size syndrome'. In orthotopic liver transplantation (OLT), matching criteria are less stringent and non-uniform. We sought to determine whether a new parameter, the ratio of donor to recipient body surface area (BSAi), is predictive of size mismatch and/or post-transplant morbidity or mortality.

METHODS

We reviewed data on 1228 OLT recipients and stratified this data according to three categories: small-for-size (BSAi <0.6), control (BSAi = 0.6-1.4), and large-for-size (BSAi >1.4) donors.

RESULTS

We found that: (1) matching of grafts at the upper and lower extremes of BSAi had significantly reduced graft survival; (2) matches with lower BSAi sustained a less severe form of intraoperative post-reperfusion syndrome, and the incidence of hepatic artery thrombosis was high postoperatively in these grafts; (3) BSAi and donor age correlated well with the severity of intraoperative post-reperfusion hypotension; and (4) small-for-size (BSAi <0.6) and large-for-size (BSAi >1.4) grafts, as well as preoperative total bilirubin, were significant risk factors for decreased graft survival.

CONCLUSION

We conclude that the BSAi can predict clinically significant size mismatch and adverse outcomes in cadaveric whole OLT.

Liver retransplantation for primary nonfunction: analysis of a 20-year single-center experience

Initial graft function following liver transplantation is a major determinant of postoperative survival and morbidity. Primary graft nonfunction (PNF) is uncommon; however, it is one of the most serious and life-threatening conditions in the immediate postoperative period. The risk factors associated with PNF and short-term outcome have been previously reported, but there are no reports of long-term follow-up after retransplant for PNF. At our institution, 52 liver transplants had PNF (2.22%) among 2,341 orthotopic liver transplants in 2,130 patients from 1984 to 2003. PNF occurred more often in the retransplant setting. Female donors, donor age, donor days in the intensive care unit, cold ischemia time, and operating room time were significant factors for PNF. Patient as well as graft survival of retransplant for PNF was not different compared to retransplant for other causes. However, PNF for a second or third transplant did not demonstrate long-term survival, and hospital mortality was 57%. In conclusion, retransplant for PNF in the initial transplant can achieve relatively good long-term survival; however, if another transplant is needed in the setting of a second PNF, the third retransplant should probably not be done due to poor expected outcome.

Warm ischemia-reperfusion injury is decreased by tacrolimus in steatotic rat liver

Ischemia-reperfusion (I-R) injury is poorly tolerated by fatty livers, most probably secondary to reduced cellular adenosine triphosphate (ATP) levels. We investigated the effectiveness of tacrolimus pretreatment on fatty liver I-R injury in obese Zucker rats. Tacrolimus (0.3 mg/kg, intravenously) was injected 24 hours before a 75-minute ischemic period and rats were sacrificed 6 hours later. Tacrolimus modified the response to I-R observed in obese Zucker rats, when compared to nontreated obese rats: a significant reduction in hepatocyte necrosis was associated with a significant increase in hepatocyte apoptosis. In addition, cell necrosis and apoptosis were significantly and inversely correlated in lean nontreated and treated obese Zucker rats following I-R. Tacrolimus also significantly increased the hepatic ATP levels, reduced in nontreated obese rats, toward values found in lean Zucker rat livers. This protective effect of tacrolimus was further confirmed in vivo by a significantly improved survival following pretreatment with tacrolimus, 24 hours prior to ischemia. In conclusion, in obese Zucker rat livers, tacrolimus pretreatment reversed the I-R injury toward the one found in lean Zucker rats. The correlations between ATP levels and the opposite changes in necrosis and apoptotic pathways strongly suggest a cause-effect relationship between tacrolimus and changes in ATP levels.

Ischemic preconditioning improves energy state and transplantation survival in obese Zucker rat livers

Livers from obese donors often have fatty infiltrates and are more susceptible to ischemia-reperfusion injury and subsequent graft dysfunction. This often leads to the exclusion of organs from obese donors. We investigated whether ischemic preconditioning (IP, 10 min ischemia, 10 min reperfusion) preserves cellular metabolism in livers from obese Zucker rats during cold ischemia. Liver samples (-IP and +IP) were collected from obese and control lean rats at different time points of cold ischemia (CI) and analyzed by magnetic resonance spectroscopy (1H- and 31P-MRS) to assess whether IP improves hepatic cellular metabolism. IP significantly improved high energy metabolism in IP livers from obese rats when compared with obese controls during the first hours of CI. At 4 h of cold storage, obese IP livers were not different from control lean non-IP livers. The beneficial metabolic effect of IP on livers form obese rats, however, was absent at 8 h of reperfusion. In contrast, in livers from lean rats, IP resulted in improved high-energy metabolism during the entire observation period of 8 h. In a later part of the study, IP of liver grafts from obese rats before 4 h of cold storage improved recipient survival after graft transplantation. IP of liver grafts from obese rats before 4 h of CI increases 24-h survival of recipient animals from 25% to 88%.

Prostaglandin E1 improved the function of transplanted fatty liver in a rat reduced-size-liver transplantation model under conditions of permissible cold preservation

The aim of this study was to determine whether the minimum necessary volume of a moderate fatty liver graft was similar to the normal liver volume and to elucidate means for improving the function of the transplanted fatty liver if it were inferior in volume to a normal liver under conditions of permissible cold preservation. Nine-week-old male Wistar rats were used. Normal rat chow was fed to the normal liver group, and fat-enriched rat chow was fed to the fatty liver group for 4 weeks to induce a moderately fatty liver. Liver transplantation with various volumes of reduced-size grafts, including whole liver graft (100%LT), 70% volume graft (70%LT), and 30% volume graft (30%LT), was performed with both groups of rats as donors. All procedures were performed under the conditions of 2-hour cold preservation. All rats with an implanted normal liver were surviving at 7 days after the operation regardless of the graft volume (100%LT, 5 of 5; 70%LT, 5 of 5; 30%LT, 5/5). In contrast, the survival rates decreased according to the graft volume in rats implanted with fatty livers (100%LT, 8 of 8; 70%LT, 5 of 8; 30%LT, 2/8). To improve the survival of 30%LT with fatty liver, we employed two potent inhibitors of ischemia-reperfusion injury: FK506 and prostaglandin E1. Though FK506 had no advantageous effect, prostaglandin E1 significantly improved the survival rate and diminished serum levels of alanine aminotransferase and hyaluronic acid. In conclusion, the volume of graft necessary for successful transplantation is larger in fatty livers than in normal livers in permissible cold preservation. Also, prostaglandin E1 protects grafts against ischemia-reperfusion injury and improves the functioning of a transplanted fatty liver.