Left-sided grafts for living-donor liver transplantation and split grafts for deceased-donor liver transplantation: their impact on long-term survival

Determinants of short-term outcomes after pediatric liver transplantation: a single centre experience over 20 years

BACKGROUND

Liver transplantation (LT) is a standard-of-care therapeutic modality for selected patients with life-threatening liver disease, including children. In addition to specific clinical characteristics of pediatric LT recipients due to initial liver disease (and related comorbidities) and level of liver failure, early postoperative outcome may be dependent on the surgical technique used, related to the type of organ donor and graft. Therefore, the aims of the present retrospective study from a large single centre cohort were to identify the prognostic factors for both 1-year patient and graft survival.

METHODS

Between October 1990 and October 2010, 151 children underwent a first LT in our centre.

RESULTS

The mean age was 5.3 ± 7.4 years, and the main indication was biliary atresia (BA) (49.0%). Living donor liver transplantation (LDLT) was performed in 39 cases (25.8%). Cadaveric liver graft was a whole liver in 50 cases (33.1%) and a partial liver (reduced or split) in 62 cases (41.1%). One-year patient and graft survival rates were 88.7% and 86.1%, respectively. Multivariate analysis disclosed that initial liver disease, location at time of LT, donor/recipient (D/R) delta age, early post-transplant hemodialysis and initial immunosuppression (induction) were significantly associated with patient survival and that D/R delta age, primary non-function, early post-transplant hemodialysis and initial immunosuppression (induction) were significantly associated with graft survival.

CONCLUSION

The results of our single-centre experience of pediatric LT emphasize that early patient and graft survivals depend on pre-operative/operative factors such as initial liver disease, D/R delta age and immunosuppressive regimen. Awareness of these factors can help in the decision making for children requiring LT.

Oxidative stress and extracellular matrices after hepatectomy and liver transplantation in rats

AIM: To investigate oxidative stress (OS)-mediated damage and the behavior of extracellular matrices in various rat models because shear stress with portal hypertension and cold ischemia/warm reperfusion injury trigger the liver regeneration cascade after surgery. These injuries also cause fatal liver damage.

METHODS: Rats were divided into four groups according to the surgery performed: control; hepatectomy with 40% liver remnant (60% hepatectomy); orthotopic liver transplantation (OLT) with whole liver graft (100% OLT); and split OLT (SOLT) with 40% graft (40% SOLT). Survival was evaluated. Blood and liver samples were collected at 6 h after surgery. Biochemical and histopathological examinations were performed. OS-induced damage, 4-hydroxynonenal, ataxia-telangiectasia mutated kinase, histone H2AX, phosphatidylinositol 3-kinase (PI3K) and Akt were evaluated by western blotting. Behavior of extracellular matrices, matrix metalloproteinase (MMP)-9, MMP-2, tissue inhibitor of metalloproteinase (TIMP)-1 and TIMP-2 were also evaluated by western blotting and zymography.

RESULTS: Although 100% OLT survived, 60% hepatectomy and 40% SOLT showed poor survival. Histopathological, immunohistological, biochemical and protein assays revealed that 60% hepatectomy, 100% OLT and 40% SOLT showed liver damage. PI3K and Akt were decreased in 60% hepatectomy and 40% SOLT. For protein expression, 40% SOLT showed differences in MMP-9, MMP-2 and TIMP-2. TIMP-1 showed differences in 60% hepatectomy and 40% SOLT. For protein activity, MMP-9 demonstrated significant differences in 60% hepatectomy, 100% OLT and 40% SOLT.

CONCLUSION: Under conditions with an insufficient liver remnant, prevention of OS-induced damage via the Akt/PI3K pathway may be key to improve the postoperative course. MMP-9 may be also a therapeutic target after surgery.

Pretreatment of Small-for-Size Grafts In Vivo by γ -Aminobutyric Acid Receptor Regulation against Oxidative Stress-Induced Injury in Rat Split Orthotopic Liver Transplantation

Background. Graft pretreatment to limit postoperative damage has the advantage of overcoming a current issue in liver transplantation (LT). The strategic potential of graft pretreatment in vivo by a specific agonist for γ -aminobutyric acid receptor (GABAR) was investigated in the rat LT model with a small-for-size graft (SFSG). Methods. Recipient rats were divided into three groups according to donor treatments and recipient surgeries: (i) saline and laparotomy, (ii) saline and split orthotopic liver transplantation (SOLT) with 40%-SFSG, and (iii) GABAR agonist and SOLT with 40%-SFSG. Survival was evaluated. Blood and liver samples were collected 6 h after surgery. Immunohistological assessment for apoptotic induction and western blotting for 4-hydroxynonenal, ataxia-telangiectasia mutated kinase (ATM), histone H2AX, phosphatidylinositol-3 kinase (PI3K), Akt, and free radical scavenging enzymes were performed. Results. Pretreatment by GABAR showed improvement in survival, histopathological assessment, and biochemical tests. Apoptotic induction and oxidative stress were observed after SOLT with an SFSG, and this damage was limited by GABAR regulation. GABAR regulation appeared to reduce DNA damage via the ATM/H2AX pathway and to promote cell survival via the PI3K/Akt pathway. Conclusions. Pretreatment in vivo by GABAR regulation improves graft damage after SOLT with an SFSG. This strategy may be advantageous in LT.

Matrix metalloproteinase-9 contributes to parenchymal hemorrhage and necrosis in the remnant liver after extended hepatectomy in mice

AIM: To investigate the effect of matrix metalloproteinase-9 (MMP-9) on the remnant liver after massive hepatectomy in the mouse.

METHODS: Age-matched, C57BL/6 wild-type (WT), MMP-9(-/-), and tissue inhibitors of metalloproteinases (TIMP)-1(-/-) mice were used. The mice received 80%-partial hepatectomy (PH). Samples were obtained at 6 h after 80%-PH, and we used histology, immunohistochemical staining, western blotting analysis and zymography to investigate the effect of PH on MMP-9. The role of MMP-9 after PH was investigated using a monoclonal antibody and MMP inhibitor.

RESULTS: We examined the remnant liver 6 h after 80%-PH and found that MMP-9 deficiency attenuated the formation of hemorrhage and necrosis. There were significantly fewer and smaller hemorrhagic and necrotic lesions in MMP-9(-/-) remnant livers compared with WT and TIMP-1(-/-) livers (P < 0.01), with no difference between WT and TIMP-1(-/-) mice. Serum alanine aminotransaminase levels were significantly lower in MMP-9(-/-) mice compared with those in TIMP-1(-/-) mice (WT: 476 ± 83 IU/L, MMP-9(-/-): 392 ± 30 IU/L, TIMP-1(-/-): 673 ± 73 IU/L, P < 0.01). Western blotting and gelatin zymography demonstrated a lack of MMP-9 expression and activity in MMP-9(-/-) mice, which was in contrast to WT and TIMP-1(-/-) mice. No change in MMP-2 expression was observed in any of the study groups. Similar to MMP-9(-/-) mice, when WT mice were treated with MMP-9 monoclonal antibody or the synthetic inhibitor GM6001, hemorrhagic and necrotic lesions were significantly smaller and fewer than in control mice (P < 0.05). These results suggest that MMP-9 plays an important role in the development of parenchymal hemorrhage and necrosis in the small remnant liver.

CONCLUSION: Successful MMP-9 inhibition attenuates the formation of hemorrhage and necrosis and might be a potential therapy to ameliorate liver injury after massive hepatectomy.

Effect of cold ischemia/reperfusion injury and/or shear stress with portal hypertension on the expression of matrix metalloproteinase-9

BACKGROUND

Matrix metalloproteinase (MMP)-9 plays an important role in liver regeneration after liver surgery. MMP-9 behavior is complicated in cold ischemia/warm reperfusion injury (CIWRI) and/or shear stress with portal hypertension. Small-for-size grafts (SFSGs) are also an issue.

MATERIALS AND METHODS

We used a rat model to examine MMP-9 expression 6 h after laparotomy, a temporal clamp (Pringle maneuver), orthotopic liver transplantation (OLT) with a whole-liver graft (100% OLT), partial hepatectomy without the Pringle maneuver (60% hepatectomy) and split orthotopic liver transplantation (SOLT) with a SFSG (40% SOLT) were investigated. Four liver samples were collected in each group.

RESULTS

The normalized ratio of MMP-9 was not significantly different with a temporal clamp (P = 0.1963), 100% OLT (P = 0.1781) and 60% hepatectomy (P = 0.2367), but it was significantly higher with 40% SOLT compared to that with laparotomy (P = 0.0159).

CONCLUSION

Forty percent SOLT is accompanied by not only CIWRI but also shear stress. This fatal damage results in increased MMP-9 expression.