Evaluation of liver transplantation services in Kazakhstan from 2012 to 2023.

There is a scarcity of publications evaluating the performance of the national liver transplantation (LTx) program in Kazakhstan. Spanning from 2012 to 2023, it delves into historical trends in LTx surgeries, liver transplant centers, and the national cohort of patients awaiting LTx. Survival analysis for those awaiting LTx, using life tables and Kaplan-Meier, is complemented by time series analysis projecting developments until 2030. The overall per million population (pmp) LTx rate varied from 0.35 to 3.77, predominantly favoring living donor LTx. Liver transplant center rates ranged from 0.06 to 0.40. Of 474 LTx patients, 364 on the waiting list did not receive transplantation. The 30-day and 1-year survival rates on the waiting list were 87.0% and 68.0%, respectively. Viral hepatitis and cirrhosis prevalence steadily rose from 2015 to 2023, with projections indicating a persistent trend until 2030. Absent targeted interventions, stable pmp rates of LTx and liver transplant centers may exacerbate the backlog of unoperated patients. This study sheds light on critical aspects of the LTx landscape in Kazakhstan, emphasizing the urgency of strategic interventions to alleviate the burden on patients awaiting transplantation.

What Is Hot and New in Basic and Translational Science in Liver Transplantation in 2023? Report of the Basic and Translational Research Committee of the International Liver Transplantation Society.

The 2023 Joint Annual Congress of the International Liver Transplantation Society, European Liver and Intestine Transplant Association, and Liver Intensive Care Group of Europe were held in Rotterdam, the Netherlands, from May 3 to 6, 2023. This year, all speakers were invited to attend the Congress in person for the first time since the COVID-19 pandemic. The congress was attended by 1159 registered delegates from 54 countries representing 5 continents, with the 10 countries comprising the bulk of the delegates. Of the 647 abstracts initially submitted, 542 were eventually presented at the meeting, coming from 38 countries (mainly North America, Europe, and Asia) and 85% of them (462 abstracts) came from only 10 countries. Fifty-three (9.8%) abstracts, originated from 17 countries, were submitted under the Basic/Translational Scientific Research category, a similar percentage as in 2022. Abstracts presented at the meeting were classified as (1) ischemia and reperfusion injury, (2) machine perfusion, (3) bioengineering and liver regeneration, (4) transplant oncology, (5) novel biomarkers in liver transplantation, (6) liver immunology (rejection and tolerance), and (7) artificial intelligence and machine learning. Finally, we evaluated the number of abstracts commented in the Basic and Translational Research Committee-International Liver Transplantation Society annual reports over the past 5 y that resulted in publications in peer-reviewed journals to measure their scientific impact in the field of liver transplantation.

Trends in Survival for Pediatric Transplantation.

OBJECTIVES: Progress in pediatric transplantation measured in the context of waitlist and posttransplant survival is well documented but falls short of providing a complete perspective for children and their families. An intent-to-treat analysis, in which we measure survival from listing to death regardless of whether a transplant is received, provides a more comprehensive perspective through which progress can be examined. METHODS: Univariable and multivariable Cox regression was used to analyze factors impacting intent-to-treat survival in 12 984 children listed for heart transplant, 17 519 children listed for liver transplant, and 16 699 children listed for kidney transplant. The Kaplan-Meier method and log-rank test were used to assess change in waitlist, posttransplant, and intent-to-treat survival. Wait times and transplant rates were compared by using χ2 tests. RESULTS: Intent-to-treat survival steadily improved from 1987 to 2017 in children listed for heart (hazard ratio [HR] 0.96, 95% confidence interval [CI] 0.96-0.97), liver (HR 0.95, 95% CI 0.94-0.97), and kidney (HR 0.97, 95% CI 0.95-0.99) transplant. Waitlist and posttransplant survival also improved steadily for all 3 organs. For heart transplant, the percentage of patients transplanted within 1 year significantly increased from 1987 to 2017 (60.8% vs 68.7%); however, no significant increase was observed in liver (68.9% vs 72.5%) or kidney (59.2% vs 62.7%) transplant. CONCLUSIONS: Intent-to-treat survival, which is more representative of the patient perspective than individual metrics alone, steadily improved for heart, liver, and kidney transplant over the study period. Further efforts to maximize the donor pool, improve posttransplant outcomes, and optimize patient care while on the waitlist may contribute to future progress.

European Liver Transplant Registry: Donor and transplant surgery aspects of 16,641 liver transplantations in children.

BACKGROUND AND AIMS: The European Liver Transplant Registry (ELTR) has collected data on liver transplant procedures performed in Europe since 1968. APPROACH AND RESULTS: Over a 50-year period (1968-2017), clinical and laboratory data were collected from 133 transplant centers and analyzed retrospectively (16,641 liver transplants in 14,515 children). Data were analyzed according to three successive periods (A, before 2000; B, 2000-2009; and C, since 2010), studying donor and graft characteristics and graft outcome. The use of living donors steadily increased from A to C (A, n = 296 [7%]; B, n = 1131 [23%]; and C, n = 1985 [39%]; p = 0.0001). Overall, the 5-year graft survival rate has improved from 65% in group A to 75% in group B (p < 0.0001) and to 79% in group C (B versus C, p < 0.0001). Graft half-life was 31 years, overall; it was 41 years for children who survived the first year after transplant. The late annual graft loss rate in teenagers is higher than that in children aged <12 years and similar to that of young adults. No evidence for accelerated graft loss after age 18 years was found. CONCLUSIONS: Pediatric liver transplantation has reached a high efficacy as a cure or treatment for severe liver disease in infants and children. Grafts that survived the first year had a half-life similar to standard human half-life. Transplantation before or after puberty may be the pivot-point for lower long-term outcome in children. Further studies are necessary to revisit some old concepts regarding transplant benefit (survival time) for small children, the role of recipient pathophysiology versus graft aging, and risk at transition to adult age.

Decreased access to pediatric liver transplantation during the COVID-19 pandemic.

BACKGROUND: The COVID-19 pandemic has affected all aspects of the US healthcare system, including liver transplantation. The objective of this study was to understand national changes to pediatric liver transplantation during COVID-19. METHODS: Using SRTR data, we compared waitlist additions, removals, and liver transplantations for pre-COVID-19 (March-November 2016-2019), early COVID-19 (March-May 2020), and late COVID-19 (June-November 2020). RESULTS: Waitlist additions decreased by 25% during early COVID-19 (41.3/month vs. 55.4/month, p < .001) with black candidates most affected (p = .04). Children spent longer on the waitlist during early COVID-19 compared to pre-COVID-19 (140 vs. 96 days, p < .001). There was a 38% decrease in liver transplantations during early COVID-19 (IRR 0.62, 95% CI 0.49-0.78), recovering to pre-pandemic rates during late COVID-19 (IRR 1.03, NS), and no change in percentage of living and deceased donors. White children had a 30% decrease in overall liver transplantation but no change in living donor liver transplantation (IRR 0.7, 95% CI 0.50-0.95; IRR 0.96, NS), while non-white children had a 44% decrease in overall liver transplantation (IRR 0.56, 95% CI 0.40-0.77) and 81% decrease in living donor liver transplantation (IRR 0.19, 95% CI 0.02-0.76). CONCLUSIONS: The COVID-19 pandemic decreased access to pediatric liver transplantation, particularly in its early stage. There were no regional differences in liver transplantation during COVID-19 despite the increased national sharing of organs. While pediatric liver transplantation has resumed pre-pandemic levels, ongoing racial disparities must be addressed.

Inactive status is an independent predictor of liver transplant waitlist mortality and is associated with a transplant centers median meld at transplant.

BACKGROUND: Approximately 30% of patients on the liver transplant waitlist experience at least one inactive status change which makes them temporarily ineligible to receive a deceased donor transplant. We hypothesized that inactive status would be associated with higher mortality which may differ on a transplant centers' or donor service areas' (DSA) Median MELD at Transplant (MMaT). METHODS: Multi-state models were constructed (OPTN database;06/18/2013-06/08/2018) using DSA-level and transplant center-level data where MMaT were numerically ranked and categorized into tertiles. Hazards ratios were calculated between DSA and transplant center tertiles, stratified by MELD score, to determine differences in inactive to active transition probabilities. RESULTS: 7,625 (30.2% of sample registrants;25,216 total) experienced at least one inactive status change in the DSA-level cohort and 7,623 experienced at least one inactive status change in the transplant-center level cohort (30.2% of sample registrants;25,211 total). Inactive patients with MELD≤34 had a higher probability of becoming re-activated if they were waitlisted in a low or medium MMaT transplant center or DSA. Transplant rates were higher and lower re-activation probability was associated with higher mortality for the MELD 26-34 group in the high MMaT tertile. There were no significant differences in re-activation, transplant probability, or waitlist mortality for inactivated patients with MELD≥35 regardless of a DSA's or center's MMaT. CONCLUSION: This study shows that an inactive status change is independently associated with waitlist mortality. This association differs by a centers' and a DSAs' MMaT. Prioritization through care coordination to resolve issues of inactivity is fundamental to improving access.

C-Reactive Protein Is an Independent Predictor of 30-Day Bacterial Infection Post-Liver Transplantation.

The relationship between aseptic systemic inflammation and postoperative bacterial infection is unclear. We investigated the correlation of systemic inflammation biomarkers with 30-day clinically significant bacterial infections (CSI) after liver transplantation (LT). This retrospective study enrolled 940 patients who received LT and were followed for 30 days. The primary end point was 30-day CSI events. The cohort was divided into exploratory (n = 508) and validation (n = 432) sets according to different centers. Area under the receiver operated characteristic (AUROC) and Cox regression models were fitted to study the association between baseline systemic inflammation levels and CSI after LT. A total of 255 bacterial infectious events in 209 recipients occurred. Among systemic inflammation parameters, baseline C-reactive protein (CRP) was independently associated with 30-day CSI in the exploratory group. The combination of CRP and organ failure number showed a good discrimination for 30-day CSI (AUROC = 0.80, 95% CI, 0.76-0.84) and the results were confirmed in an external verification group. Additionally, CRP levels were correlated with bacterial product lipopolysaccharide. In conclusion, our study suggests that pre-transplantation CRP is independent of other prognostic factors for 30-day CSI post-LT, and can be integrated into tools for assessing the risk of bacterial infection post-LT or as a component of prognostic models.

Advances in Liver Transplantation: where are we in the pursuit of transplantation tolerance?

Liver transplantation is the ultimate treatment option for end-stage liver disease. Breakthroughs in surgical practice and immunosuppression have seen considerable advancements in survival after transplantation. However, the intricate management of immunosuppressive regimens, balancing desired immunological quiescence while minimizing toxicity has proven challenging. Diminishing improvements in long-term morbidity and mortality have been inextricably linked with the protracted use of these medications. As such, there is now enormous interest to devise protocols that will allow us to minimize or completely withdraw immunosuppressants after transplantation. Immunosuppression withdrawal trials have proved the reality of tolerance following liver transplantation, however, without intervention will only occur after several years at the risk of potential cumulative immunosuppression-related morbidity. Focus has now been directed at accelerating this phenomenon through tolerance-inducing strategies. In this regard, efforts have seen the use of regulatory cell immunotherapy. Here we focus particularly on regulatory T cells, discussing preclinical data that propagated several clinical trials of adoptive cell therapy in liver transplantation. Furthermore, we describe efforts to further optimize the specificity and survival of regulatory cell therapy guided by concurrent immunomonitoring studies and the development of novel technologies including chimeric antigen receptors and co-administration of low-dose IL-2.

The evolution of surgery for colorectal liver metastases: A persistent challenge to improve survival.

Only a few decades ago, the opinion that colorectal liver metastases were a palliative diagnosis changed. In fact, previously, the prevailing view was strongly resistant against resecting colorectal liver metastases. Constant technical improvement of liver surgery and, much later, effective chemotherapy allowed for a successful wider application of surgery. The clinical use of portal vein embolization was the starting signal of regenerative liver surgery, where insufficient liver volume can be expanded to an extent where safe resection is possible. Today, a number of these techniques including portal vein ligation, associating liver partition and portal vein ligation for staged hepatectomy, and bi-embolization (portal and hepatic vein) can be successfully used to address an insufficient future liver remnant in staged resections. It turned out that the road to success is embedding surgery in a well-orchestrated oncological concept of controlling systemic disease. This concept was the prerequisite that meant liver transplantation could enter the treatment strategy for colorectal liver metastases, ending up with a 5-year overall survival of 80% in highly selected cases. In particular, techniques combining principles of 2-stage hepatectomy and liver transplantation, such as "resection and partial liver segment 2-3 transplantation with delayed total hepatectomy" (RAPID) are on the rise. These techniques enable the use of partial liver grafts with primarily insufficient liver volume. All this progress also prompted a number of innovative local therapies to address recurrences ultimately transferring colorectal liver metastases from instantly deadly into a chronic disease in some cases.

Impact of COVID-19 Pandemic on Liver Transplantation and Alcohol-Associated Liver Disease in the USA.

BACKGROUND AND AIMS: The surge in unhealthy alcohol use during the COVID-19 pandemic may have detrimental effects on the rising burden of alcohol-associated liver disease (ALD) on liver transplantation (LT) in the USA. We evaluated the effect of the pandemic on temporal trends for LT including ALD. APPROACH AND RESULTS: Using data from United Network for Organ Sharing, we analyzed wait-list outcomes in the USA through March 1, 2021. In a short-period analysis, patients listed or transplanted between June 1, 2019, and February 29, 2020, were defined as the "pre-COVID" era, and after April 1, 2020, were defined as the "COVID" era. Interrupted time-series analyses using monthly count data from 2016-2020 were constructed to evaluate the rate change for listing and LT before and during the COVID-19 pandemic. Rates for listings (P = 0.19) and LT (P = 0.14) were unchanged during the pandemic despite a significant reduction in the monthly listing rates for HCV (-21.69%, P < 0.001) and NASH (-13.18%; P < 0.001). There was a significant increase in ALD listing (+7.26%; P < 0.001) and LT (10.67%; P < 0.001) during the pandemic. In the COVID era, ALD (40.1%) accounted for more listings than those due to HCV (12.4%) and NASH (23.4%) combined. The greatest increase in ALD occurred in young adults (+33%) and patients with severe alcohol-associated hepatitis (+50%). Patients with ALD presented with a higher acuity of illness, with 30.8% of listings and 44.8% of LT having a Model for End-Stage Liver Disease-Sodium score ≥30. CONCLUSIONS: Since the start of COVID-19 pandemic, ALD has become the most common indication for listing and the fastest increasing cause for LT. Collective efforts are urgently needed to stem the rising tide of ALD on health care resources.

Research progress on hepatic machine perfusion.

Nowadays, liver transplantation is the most effective treatment for end-stage liver disease. However, the increasing imbalance between growing demand for liver transplantation and the shortage of donor pool restricts the development of liver transplantation. How to expand the donor pool is a significant problem to be solved clinically. Many doctors have devoted themselves to marginal grafting, which introduces livers with barely passable quality but a high risk of transplant failure into the donor pool. However, existing common methods of preserving marginal grafts lead to both high risk of postoperative complications and high mortality. The application of machine perfusion allows surgeons to make marginal livers meet the standard criteria for transplant, which shows promising prospect in preserving and repairing donor livers and improving ischemia reperfusion injury. This review summarizes the progress of recent researches on hepatic machine perfusion.

Impact of the COVID-19 pandemic on liver donation and transplantation: A review of the literature.

The coronavirus disease 2019 (COVID-19) pandemic has upended healthcare systems worldwide and led to an inevitable decrease in liver transplantation (LT) activity. During the first pandemic wave, administrators and clinicians were obliged to make the difficult decision of whether to suspend or continue a life-saving procedure based on the scarce available evidence regarding the risk of transmission and mortality in immunosuppressed patients. Those centers where the activity continued or was heavily restricted were obliged to screen donors and recipients, design COVID-safe clinical pathways, and promote telehealth to prevent nosocomial transmission. Despite the ever-growing literature on COVID-19, the amount of high-quality literature on LT remains limited. This review will provide an updated view of the impact of the pandemic on LT programs worldwide. Donor and recipient screening, strategies for waitlist prioritization, and posttransplant risk of infection and mortality are discussed. Moreover, a particular focus is given to the possibility of donor-to-recipient transmission and immunosuppression management in COVID-positive recipients.

Impact of Morbid Obesity on Liver Transplant Candidacy and Outcomes: National and Regional Trends.

BACKGROUND: Body mass index (BMI) limits for liver transplant (LT) candidacy are controversial. In this study, we evaluate waitlist and post-LT outcomes, and prognostic factors and examine regional patterns of LT waitlist registration in patients with BMI ≥40 versus BMI 18-39. METHODS: United Network for Organ Sharing (UNOS) data were analyzed to assess waitlist dropout, post-LT survival, and prognostic factors for patient survival. The distribution of waitlisted patients with BMI ≥40 was compared with the Centers for Disease Control Behavioral Risk Factors Surveillance System data to explore the rates of morbid obesity in the general population of each UNOS region. RESULTS: Post-LT outcomes demonstrate a small but significantly lower 1- and 3-y overall survival for patients with BMI ≥45. Risk factors for post-LT mortality for patients with BMI ≥40 included age >60 y, prior surgery, and diabetes on multivariable analysis. Model for End-Stage Liver Disease >30 was significant on univariable analysis only, likely due to the limited number of patients with BMI ≥40; however, median Model for End-Stage Liver Disease scores in this BMI group were higher than those in patients with lower BMI across all UNOS regions. Patients with BMI ≥40 had a higher waitlist dropout in 4 regions. Comparison with BRFSS data illustrated that the proportion of waitlisted patients with BMI ≥40 was significantly lower than the observed rates of morbid obesity in the general population in 3 regions. CONCLUSIONS: While BMI ≥45 is associated with modestly lower patient survival, careful selection may equalize these numbers.

Mycophenolate mofetil enhances the effects of tacrolimus on the inhibitory function of regulatory T cells in patients after liver transplantation via PD-1 and TIGIT receptors.

OBJECTIVE: Regulatory T cells (Tregs) induce immune tolerance in patients after organ transplantation. Various immunosuppressors can affect Tregs function through different mechanisms. PD-1 and TIGIT are important receptors on Tregs surface. Here, we investigated the effects of Tacrolimus and mycophenolate mofetil (MMF) on the inhibitory function of Tregs and explored the regulatory mechanism in patients after liver transplantation. METHODS: Thirty patients that underwent a liver transplant and 15 healthy people were enrolled. Fifteen patients received Tacrolimus only, and 15 received a combination of Tacrolimus and MMF. Tregs and effector T cells (Teffs) were isolated using magnetic beads and were mixed at different ratios of 0:1, 1:4, 1:2 and 1:1. An inhibition assay was performed by adding anti-PD-1 and anti-TIGIT when the mixture ratio was 1:1. The Tregs inhibition rate was determined and the levels of IFN-γ and TNF-α were measured. RESULTS: As the ratios of Tregs to Teffs in the mixture increased, the Tregs inhibition rate increased and the levels of IFN-γ and TNF-α decreased. At each mixture ratio, Tacrolimus + MMF group had the highest Tregs inhibition rate compared to Tacrolimus and control group. At the specific mixture ratio of 1:1, the addition of both anti- PD-1 and anti-TIGIT led to lower Tregs inhibition rate and higher IFN-γ and TNF-α levels in all three groups as opposed to the addition of each antibody separately. Additionally, both the decrease in the Tregs inhibition rate and the increase in the IFN-γ and TNF-α levels were the most for Tacrolimus + MMF group among all cases, either adding antibodies alone or mixed. CONCLUSION: Tacrolimus and MMF enhanced the function of Tregs by synergistically affecting PD-1 and TIGIT in liver transplant patients.