Transplantation: current developments and future directions

Across all solid organs, adolescent age recipients have worse transplant organ survival than younger age children: A US national registry analysis

Univariate analyses suggest that adolescents have worse long-term allograft survival versus younger children across different SOT. This study's objective was to determine whether multivariate analyses of a large national database recording all deceased SOT (KI; LI; HR; LU) also show worse adolescent allograft survival in the different organs. Using data from the national Scientific Registry for Transplant Recipients in the USA for pediatric primary SOT from 1989 to 2010, we calculated median half-lives and constructed K-M graft survival curves. Recipient age at transplant (<12 or adolescent 12-17 yr) was fitted with other identical covariates into multivariate Cox proportional hazards models. In all SOT recipients, unadjusted graft survival curves demonstrated better graft survival for adolescents initially, followed by crossing of the lines, such that adolescent SOT recipients had worse survival after one yr (KI), 4.6 yr (LI), 4.4 yr (HR), and 1.6 yr (LU). Multivariate models of the post-cross period showed a significantly higher AHR for worse graft survival in adolescent age across all four SOTs: AHR 1.400 (KI), 1.958 (LI), 1.414 (HR), and 1.576 (LU). Improving adolescent long-term outcomes across all four organs will be a defining issue in the future.

Lack of significant improvements in long-term allograft survival in pediatric solid organ transplantation: A US national registry analysis

Improvements across many facets of transplantation have led to better 1-yr outcomes of transplanted organs. In this study, we assessed whether longer-term attrition rates improved in pediatric kidney (KI), liver (LI), heart (HR) and lung (LU) transplant (TX) survival. We analyzed data between 1989 and 2008 from 5747 KI, 7348 LI, 5103 HR, and 715 LU TXs (under 18 yr of age at transplant, first solitary transplant only), from the National Scientific Registry of Transplant Recipients database in the USA. Kaplan-Meier (K-M) or ordinary least square (OLS) estimates were used to calculate median and projected survival half-lives. Attrition rates, defined as percent failing within a given time period, were stratified by year of TX. Median half-lives from 1989 TX year to 2005 TX year have shown a major improvement only in LI TX, remaining unchanged in HR and KI TX, or remaining very low in LU TX. All four organ TX types have shown a dramatic drop in first-year attrition rates from 1989 to 2008. However, longer-term attrition rates (1-3, 3-5, 5-10 yr) have remained largely unchanged for all four organ TX types. Further progress in long-term survival will need targeting end-points beyond first-year rejection and survival rates.

Nonfrozen preservation of articular cartilage by epigallocatechin-3-gallate reversibly regulating cell cycle and NF-kappaB expression

Epigallocatechin-3-O-gallate (EGCG) is known to have beneficial effects on the nonfrozen preservation of mammalian cells and tissues. In this study, we aimed at testifying the hypothesis that the deleterious effects of cold preservation of articular cartilages can be ameliorated by the addition of EGCG to the storage media. Articular cartilages were preserved in a storage solution composed of serum-free RPMI 1640 media with 1 mM EGCG at 4 degrees C for 1-4 weeks. The regulatory effects of EGCG on cell cycle progression as well as expression levels of CyCliNS (CCNs) and nuclear factor-kappaB (NF-kappaB) were investigated in articular chondrocytes. Chondrocyte viability of cartilages preserved with EGCG was significantly well maintained for 2 weeks with high contents of glycosaminoglycan and total collagen. These beneficial effects of EGCG were confirmed by histological and immunohistochemical observations showing well-preserved cartilaginous structures and delayed denaturation of extracellular matrices. The compressive elastic modulus of cartilages preserved with EGCG was close to that of fresh specimens. Increased cell population at the G(0)/G(1) phase by EGCG returned to the normal level after EGCG removal, whereas decrease at the G(2)/M phase did not. Negatively regulated expression of CCND1, CCNE2, or NF-kappaB in EGCG-treated cells was restored by removing EGCG, but not CCNA2 and CCNB1. After 8 weeks of in vivo implantation into full-thickness cartilage defects in rabbits, the cartilages preserved with EGCG were found to be integrated with the host environment and support tissue regeneration. It is suggested that EGCG plays effective roles in preserving and repairing articular cartilages by reversibly regulating cell cycle at G(0)/G(1) phase and NF-kappaB expression.

Liver transplantation is an alternative treatment of hepatocellular carcinoma beyond the Milan criteria

BACKGROUND

The decision to perform liver transplantation (LT) or liver resection (LR) for patients with hepatocellular carcinoma (HCC) who are beyond the Milan criteria remains controversial.

METHODS

We retrospectively analyzed outcome data for 179 patients with HCC beyond the Milan criteria who were treated with LR (n = 135) or LT (n = 44). Univariate and multivariate Cox proportional hazard models were established. Kaplan-Meier survival curves were generated, and a log-rank test was performed to compare group survival status.

RESULTS

Patients who underwent LR group were significantly older, had a lower TNM stage, and were more likely to have unilateral disease and noncirrhotic liver. Significantly more patients in the LR group had recurrence (53.3% vs 29.5%) or died (61.5% vs 43.2%) than patients in the LT group. Recurrence-free survival rates were 11.9% for the LR group and 61.5% for the LT group. The median overall survival duration showed no statistically difference between the LR group (28.0 months) and the LT group (50.0 months).

CONCLUSIONS

LT may be the better choice for patients with HCC beyond the Milan criteria.

Isoforms of human leukocyte antigen-G and their inhibitory receptors in human kidney allograft acceptance

Novel therapeutic strategies such as the modulation of dendritic cell and T-cell function have exhibited great potential in clinical transplantation. Human leukocyte antigen (HLA)-G is a molecule that plays a significant role in establishing complex mechanisms to protect semiallogeneic fetuses from rejection by the maternal immune system. The unique characteristics of both cell-surface and soluble isoforms of HLA-G, the formation of disulfide-bonded dimers with the potential to augment inhibitory receptor signaling, and the function of HLA-G as a preferential ligand for the immunoglobulin-like transcript receptors make HLA-G very important in fundamental approaches for the modulation of immune responses to improve allogeneic graft survival in clinical transplantation. Experimental data from several groups as well as our data from experiments involving HLA-G-mediated human tolerogenic dendritic cells in vitro and receptor transgenic mice in vivo indicate that different isoforms of HLA-G have various immunomodulatory effects through the inhibitory receptors. This knowledge is crucial in understanding mechanisms of prolongation of allograft survival. The analyses of HLA-G isoforms and inhibitory receptors in patients with kidney allograft and the relationship among different isoforms of HLA-G, inhibitory receptors, their mediated immunoregulation, and graft acceptance or failure will be discussed here.