A Decade of Liver Transplantation in the United States: Drivers of Discard and Underutilization.

Background: Organ shortage remains a major challenge for the field of transplantation. Maximizing utilization and minimizing discard of available organs is crucial to reduce waitlist times. Our aim was to investigate the landscape of liver recovery, discard over the past decade in the United States, and identify areas to reduce organ discard. Methods: This study used the Scientific Registry of Transplant Recipients United Network for Organ Sharing database to analyze the rates and associated reasons of discarded organs from 2010 to 2021. All deceased donors were evaluated, and data were analyzed by organ type, year, and region. Organ disposition was analyzed by year and region. Donor demographics and liver biopsy data were also analyzed. Results: The volume of liver transplantation increased steadily, with a 44% increase from 2010 to 2021. Donation after circulatory death transplantation increased by 239%, comprising 10.6% of transplants in 2021, yet discard rates remained high at 30% for this donor subset. For all donor types, the liver discard rate has remained stable around 10% despite a 74% increase in available donors. Seventy percent of liver discards were attributed to organ factors, with biopsy findings accounting for 40% of all discards. Of livers that were biopsied, 70% had macrosteatosis of <30%. Conclusions: Analysis of trends in transplantation and discard allow for identifying areas of underutilization. Donation after circulatory death livers have expanded the pool of transplanted livers but remain discarded at high rates. Significant differences remain in discard rates between geographic regions. We identify several areas to lower the discard rates. The expanding role of machine perfusion may allow for utilization of previously discarded organs.

Analysis of gene polymorphisms in the regulatory region of MCP-1, RANTES, and CCR5 in liver transplant recipients.

Chemokines and their receptors play a major role in the inflammatory and immune responses that mediate allograft outcome. The production of some chemokines varies among individuals and these variations may be determined by genetic polymorphisms, most commonly within the regulatory region of the gene. We investigated whether the functional polymorphisms of the chemokines RANTES, MCP-1 and chemokine receptor CCR5 are associated with the incidence of acute rejection and long-term liver graft survival. Two hundred nine liver transplant recipients were genotyped using polymerase chain reaction sequence-specific primers for the following polymorphisms: RANTES-28, MCP-1 -2518, and CCR5-59029. There was no association with any of the three genotypes and the incidence of acute rejection episodes. In addition, no association of RANTES-28, MCP-1 -2518, or CCR5 -59029 variants with long-term liver graft survival was found. In conclusion, variants of RANTES-28, MCP-1 -2518, and CCR5-59029 neither influenced the incidence of acute rejection nor affected long-term allograft survival upon liver transplantation in the context of this analysis.

The impact of polymorphisms in chemokine and chemokine receptors on outcomes in liver transplantation.

Chemokines and their corresponding receptors likely play a central role in directing mononuclear cells to the graft sites during rejection. Genes for the chemokine stromal derived factor-1 (SDF1) and CC chemokine receptors CCR2 and CCR5 are characterized by polymorphisms which alter their function. We genotyped DNA of 207 liver transplant recipients by PCR or PCR-RFLP for CCR2-641, CCR5delta32, and SDF1-3'A polymorphisms, and examined their association on outcomes in liver allograft recipients. Due to the low number of patients homozygous for CCR2-641 and CCR5delta32, only the effects of their heterozygous variants were addressed in this study. None of the investigated polymorphisms showed a significant shift in gene frequency in acute rejection and rejection-free groups, or for graft survival. The gene frequency of the SDF1-3'A allele was significantly (p = 0.034) higher in patients who died (29.0%, n = 31) compared to recipients still alive (17.1%, n = 172). The mean patient survival time post transplant was 134 months in patients with SDF1 wild-type, significantly (log rank p = 0.014) longer than 98 months in patients with at least one SDF1-3'A allele. The CCR2 and CCR5 polymorphisms were not associated with significant differences in mortality rate. In conclusion, CCR2-641, CCR5delta32, and SDF1-3'A genotypes did not influence the risk for acute rejection or graft survival. However, in liver allograft recipients SDF1-3'A is significantly associated with higher mortality.