Tung-Yu Tsui

A cell penetrating heme oxygenase protein protects heart graft against ischemia/reperfusion injury

Ischemia/reperfusion (I/R) injury is an unavoidable barrier that significantly affects outcome of solid organ transplantation. Here, we establish a protein transduction system to extend graft preservation time and to prevent I/R injury in heart transplantation. We generated a recombinant heme oxygenase-1 (HO-1) protein containing a modified protein transduction domain (PTD). PTD could cross cover cell membrane and carry target molecule to parenchymal cells of cold-preserved heart grafts. The newly generated PTD-HO-1 protein localized mainly in subcellular membrane organelle and nucleus after delivery that significantly prolonged cold preservation of heart grafts. This effect was associated with significantly less endothelial cell activation, less neutrophil and macrophage infiltration in PTD-HO-1-transduced heart grafts after reperfusion as compared with controls. In addition, transduction of PTD-HO-1 protein to heart graft significantly suppressed the I/R injury-associated myocardiocyte apoptosis. The infarct areas of heart graft after I/R injury were significantly reduced after PTD-HO-1 protein treatment. We show here for the first time that PTD can maintain its biological activities during cold preservation. Transduction of cell penetrating HO-1 protein significantly prolongs the cold preservation time and protects the graft from the I/R injury. This approach represents a novel method for the improvement of the overall outcome of organ transplantation.

Long-term liver allograft survival induced by combined treatment with rAAV-hCTLA4Ig gene transfer and low-dose FK506.

Background. Recombinant adeno-associated virus vector (rAAV) is a promising vehicle for gene delivery, but few reports have documented its application in solid organ transplantation. In a rat orthotopic liver transplantation model, we investigated the efficacy of rAAV-mediated human cytotoxic T-lymphocyte-associated antigen 4 and immunoglobulin G (hCTLA4Ig) gene transfer to induce long-term allograft survival. Methods. Dark Agouti and Lewis rats were used as donors and recipients, respectively, in six experimental groups: (a) syngeneic control, (b) no treatment, (c) rAAV-green fluorescent protein, (d) rAAV-hCTLA4Ig, (e) low-dose FK506 for 7 days, and (f) rAAV-hCTLA4Ig and low-dose FK506 for 7 days. Results. The liver allografts were rejected within 10 days when no treatment was given or rAAV-green fluorescent protein was delivered. rAAV-hCTLA4Ig transduction slightly prolonged the survival time to 11 days. Long-term survival was achieved using the combined treatment of rAAV-hCTLA4Ig and low-dose FK506, whereas grafts were rejected on day 33 in the low-dose FK506 group. A sustained hCTLA4 level in plasma was detected in the combined treatment group from day 5 to day 180. On postoperative day 5, combined treatment significantly decreased the interleukin-2 and interferon-&ggr; protein levels in the grafts and the number of infiltrating B, T, CD25+, CD4+, CD8+, and NK cells. Conclusion. This study shows that rAAV-hCTLA4Ig gene transfer combined with low-dose FK506 can achieve long-term liver allograft survival.

“Rescue allocation offers” in liver transplantation: Is there any reason to reject “unwanted” organs?

Abstract To increase the number of transplanted organs, the Eurotransplant foundation uses a so-called “rescue-organ-allocation” procedure for organs that had been rejected by at least three consecutive transplant centers for medical reasons. The transplant center that finally accepts such an organ can then freely choose a patient from its own waiting list, without being bound to regular allocation criteria. Almost 30% of deceased donor livers are now allocated through this process in the Eurotransplant region. We report our results of 38 “rescue-allocation” livers (RA livers) transplanted at our institution (2003–2007), compared to a group of 115 regularly allocated organs within the same period. From our data, RA livers have the same results as regularly allocated livers. Type and frequency of postoperative morbidity did not differ between both groups, though the analysis of subgroups showed a tendency toward reduced survival of RA livers in patients with viral hepatitis. Interestingly, the Donor Risk Index (DRI) showed no difference between RA livers and regularly allocated livers. Although preliminary due to small numbers, we conclude that RA livers can be safely transplanted without increased mortality or morbidity. However, no donor specific criteria which would justify rejecting a RA liver were found. This highly challenges the applicability of the RA procedure in its current form.

Liver transplantation as curative approach for advanced hepatocellular carcinoma: is it justified?

BackgroundsLiver transplantation is considered as one of therapeutic approaches to hepatocellular carcinoma (HCC). The present study aims to evaluate the efficacy of various therapeutic options for HCC.Materials and methodsOne hundred twenty patients with known HCC in various tumour stages were evaluated in the present study. Patients were treated either with primary tumour resection, transarterial chemoembolisation (TACE) or liver transplantation (LTx) by an interdisciplinary team.ResultsThe overall 1-year and 5-year survivals of patients in LTx group were 95 and 57%, respectively, which were significantly higher than those in primary tumour resection group (65 and 33%, P < 0.01) and those in TACE group (44 and 4%, P < 0.01). In parallel, 1-year and 5-year tumour-free survivals of patients in LTx group (75 and 62%) were significantly higher than those in primary tumour resection group (50 and 11%, P < 0.01). There were no significant differences in 1- and 5-year survivals of patients with early tumour stage received LTx or primary tumour resection, whereas patients in advanced tumour stage based on pathological findings of explanted liver significantly benefited from LTx as compared to primary resection.ConclusionsLTx can be a curative approach for patients with advanced HCC without extrahepatic metastasis. However, organ shortage is a major limiting factor in the selection of HCC patients for LTx.

Targeting of interleukin-10 is superior to cytotoxic T-lymphocyte associated antigen 4 with human immunoglobulin G 1 for the prevention of chronic allograft deterioration in organ transplantation

Genetic manipulation of the allograft is an attractive approach to prevent the graft against chronic deterioration through stable expression of immunomodulatory or protective genes. However, the best strategy for prevention of chronic allograft deterioration remains unclear.