Current state of clinical end-points assessment in transplant: Key points

The impact of pretransplant suspected HLA antibody on the long-term outcome of the graft kidney: A retrospective cohort study

INTRODUCTION

The preoperative examination of kidney transplantation includes HLA antibody screening to initially determine the presence of preexisting donor-specific antibody (DSA) that mediates hyperacute rejection. Recipients with positive HLA antibodies require further HLA specificity analysis to type the antigen and determine the antigen mismatches between the donor and recipient. However, recipients with suspected antibodies would have no further HLA specificity analysis. It is unclear whether suspected HLA antibodies would affect renal graft function. This study aimed to explore the impact of pretransplant suspected HLA antibody on the long-term outcome of the graft kidney and thus determine the necessity of routinely performing the HLA specificity analysis in recipients with suspected HLA antibodies preoperatively.

METHODS

This is a single-center retrospective cohort study. 179 kidney transplant recipients (KTRs) were included and further divided into HLA antibody-negative group (Group 1) and HLA antibody-suspected groups (Group 2) based on the result of the pretransplant HLA antibody screen test. And the antibody-suspected group was further divided into a low-mismatched group (Group A) and a high-mismatched group (Group B) according to the HLA specificity analysis. We tracked the renal function indexes, biochemical indexes, and posttransplant adverse events within 5 years after transplantation and explored the necessity of further HLA specificity analysis in recipients with pretransplant suspected HLA antibodies.

RESULTS

There was no statistically significant difference in demographics between HLA antibody-negative group and HLA antibody-suspected groups. At 5 years of follow-up, the KTRs in HLA antibody-negative group had significantly higher eGFR levels, lower serum creatinine levels, and less urinary protein compared to those in antibody-suspected group. Meanwhile, the KTRs in low-mismatched group also had significantly higher eGFR levels, lower serum creatinine levels, and less proteinuria compared to those in high-mismatched group. Correlation analysis showed that the age of KTRs, urinary protein levels and the load capacity of HLA mismatches were associated with eGFR levels of KTRs at 5 year posttransplant.

CONCLUSION

KTRs with suspected HLA antibodies before kidney transplantation have worse graft function than the preoperative HLA antibody-negative recipients in the long-term posttransplant follow-up. The specific load capacity of HLA mismatches, the age of the recipient and the urinary protein was found to be negatively correlated with long-term posttransplant renal outcomes. It is necessary to undergo further HLA specificity analysis for recipients with suspected HLA antibodies in HLA antibody screen test to explicit HLA mismatches and improve long-term posttransplant outcomes.

Kidney transplant in the next decade: Strategies, challenges and vision of the future

Although the results of kidney transplantation (KT) have improved substantially in recent years, a chronic and inexorable loss of grafts mainly due to the death of the patient and chronic dysfunction of the KT, continues to be observed. The objectives, thus, to optimize this situation in the next decade are fundamentally focused on minimizing the rate of kidney graft loss, improving patient survival, increasing the rate of organ procurement and its distribution, promoting research and training in health professionals and the development of scientific registries providing clinical and reliable information that allow us to optimize our clinical practice in the field of KT. With this perspective, this review will deep into: (1) strategies to avoid chronic dysfunction and graft loss in the medium and long term; (2) to prolong patient survival; (3) strategies to increase the donation, maintenance and allocation of organs; (4) promote clinical and basic research and training activity in KT; and (5) the analysis of the results in KT by optimizing and merging scientific registries.

Effects of preservative fluid associated possible donor-derived carbapenem-resistant Klebsiella Pneumoniae infection on kidney transplantation recipients

BACKGROUND

Infections remain a major cause of morbidity and mortality in kidney transplant (KT) recipients. This study aimed to investigate the preservation fluid (PF) samples from deceased donors and report the impacts of possible donor-derived carbapenem-resistant Klebsiella pneumoniae (pdd-CRKP) infections on KT recipients.

METHODS

A retrospective study was performed that included all recipients who received kidney transplantation from deceased donors in our hospital between December 2018 and December 2020. A total of 212 patients received kidney transplantation from deceased donors, a total of 206 PF samples were collected, and 20 recipients had a CRKP-positive culture. Both donors and recipients with CRKP-positive PF cultures were divided into two groups, and continuous variables between the two groups were compared using independent-sample t tests and Mann-Whitney tests. Categorical variables were compared using the chi-square test or Fisher's exact test. The significance level of p values was set at 0.05.

RESULTS

A total of 337 recipients underwent kidney transplantation, including 212 recipients of organs from deceased donors and 110 corresponding deceased donors. A total of 206 PF samples were collected, and 20 recipients had CRKP-positive PF cultures. The donors' length of ICU stay was a potential risk factor for CRKP positivity in the PF culture (P < 0.05). Fifteen recipients were infected with pdd-CRKP, and the incidence of pdd-CRKP infection was 7.3% (15/206). The use of antibiotics, including ceftazidime-avibactam (CAZ-AVI), was a potential protective factor against death and graft loss in recipients with a CRKP-positive PF culture (P < 0.05).

CONCLUSIONS

This study shows that the incidence of pdd-CRKP is high in our centre, recipients with pdd-CRKP infection can still achieve a good prognosis with the use of antimicrobial agents including CAZ-AVI.

Single mutidrug resistant enterobacteriacae donor-derived infection in four solid organ transplant recipients: a case report

Background

Bacteraemia of the donor is not considered to be contraindication of organ procurement. On the other hand, infection of solid organ transplant recipients remains to be a major cause of their morbidity and mortality. When using organs from bacteraemic donors, individual risks need to be assessed and the appropriate antibiotic treatment applied.

Case presentation

In this case series we report several serious donor–derived infectious complications in four out of five recipients of different organs from one single donor in the early posttransplant period. Donor-transmitted multi-drug resistant strains of Escherichia coli and Klebsiella pneumonia was confirmed by both serologic and molecular testing.

Conclusions

To prevent donor-derived infections, careful microbiological screening followed by targeted antibiotic treatment is essential. Although such complications can never by completely prevented, a high index for potential bacterial infection in organ donors and transplant recipients should be routinely employed.

Kidney transplant registries: How to optimise their utility?

The scientific Registries (RE) in renal transplantation (Tx) are very useful since they allow us to identify risk factors in this population and facilitate contrasting the information with other national and international registries, contributing to establishing strategies which improve outcomes in terms of survival. They constitute an organised and planned system that uses observational methods and standardised systematic processes, including adjusted risk models, to essentially evaluate survival outcomes. The scientific RE are complemented with clinical trials providing scientific evidence, but inexcusably need adequate statistical analysis to generate reliable clinical data that contribute to optimising the prognosis of the transplant population. In addition, scientific RE provide valuable information on the performance of Tx programmes and help generate prognostic indexes, which could contribute to improving survival. Under these prerequisites, this review will assess the following aspects related to the scientific RE in the Tx: 1) the concept and importance of implementing RE in Tx; 2) the measures that are needed for the correct execution of the scientific RE; 3) the benefits, quality and limitations of RE; 4) the statistical tools for the adequate analysis of survival; and 5) utility of RE in the evaluation of performance, quality and surveillance of transplant programmes and the generation of comorbidity índices.

Reported effects of the Scientific Registry of Transplant Recipients 5-tier rating system on US transplant centers: results of a national survey

In the United States, the Scientific Registry of Transplant Recipients (SRTR) provides publicly available quality report cards. These reports have historically rated transplant programs using a 3-tier system. In 2016, the SRTR temporarily transitioned to a 5-tier system, which classified more programs as under-performing. As part of a larger survey about transplant quality metrics, we surveyed members of the American Society of Transplant Surgeons and American Society of Transplantation (N = 280 respondents) on transplant center experiences with patient and payer responses to the 5-tier SRTR ratings. Over half of respondents (n = 137, 52.1%) reported ≥1 negative effect of the new 5-tier ranking system, including losing patients, losing insurers, increased concern among patients, and increased concern among referring providers. Few respondents (n = 35, 13.7%) reported any positive effects of the 5-tier ranking system. Lower SRTR-reported scores on the 5-tier scale were associated with increased risk of reporting at least one negative effect in a logistic model (P < 0.01). The change to a more granular rating system provoked an immediate response in the transplant community that may have long-term implications for transplant hospital finances and patient options for transplantation.

Mortality in Elderly Waiting-List Patients Versus Age-Matched Kidney Transplant Recipients: Where is the Risk?

The number of elderly patients on the waiting list (WL) for kidney transplantation (KT) has risen significantly in recent years. Because KT offers a better survival than dialysis therapy, even in the elderly, candidates for KT should be selected carefully, particularly in older waitlisted patients. Identification of risk factors for death in WL patients and prediction of both perioperative risk and long-term post-transplant mortality are crucial for the proper allocation of organs and the clinical management of these patients in order to decrease mortality, both while on the WL and after KT. In this review, we examine the clinical results in studies concerning: a) risk factors for mortality in WL patients and KT recipients; 2) the benefits and risks of performing KT in the elderly, comparing survival between patients on the WL and KT recipients; and 3) clinical tools that should be used to assess the perioperative risk of mortality and predict long-term post-transplant survival. The acknowledgment of these concerns could contribute to better management of high-risk patients and prophylactic interventions to prolong survival in this particular population, provided a higher mortality is assumed.

County socioeconomic characteristics and heart transplant outcomes in the United States

BACKGROUND

Geographic disparities in survival after heart transplantation have received mixed support in prior studies, and specific geographic characteristics that might be responsible for these differences are unclear. We tested for differences in heart transplant outcomes across United States (US) counties after adjustment for individual-level covariates. Our secondary aim was to evaluate whether specific county-level socioeconomic characteristics explained geographic disparities in survival.

METHODS

Data on patients aged ≥18 years undergoing a first-time heart transplant between July 2006 and December 2014 were obtained from the United Network for Organ Sharing. Residents of counties represented by <5 patients were excluded. Patient survival (censored in March 2016) was analyzed using multivariable Cox regression. Shared frailty models were used to test for residual differences in overall all-cause mortality across counties after adjusting for recipient and donor characteristics. Measures of county economic disadvantage, inequality, and racial segregation were obtained from US Census data and coded into quintiles. A likelihood ratio test determined whether adjusting for each county measure improved the fit of the Cox model.

RESULTS

Multivariable analysis of 10,879 heart transplant recipients found that, adjusting for individual-level characteristics, there remained statistically significant variation in mortality hazard across US counties (P=.004). Adjusting for quintiles of community disadvantage, economic inequality, or racial segregation did not significantly improve model fit (likelihood ratio test P=.092, P=.273, and P=.107, respectively) and did not explain residual differences in patient survival across counties.

CONCLUSIONS

Heart transplantation outcomes vary by county, but this difference is not attributable to county-level socioeconomic disadvantage.

Melatonin as an antioxidant: under promises but over delivers

Melatonin is uncommonly effective in reducing oxidative stress under a remarkably large number of circumstances. It achieves this action via a variety of means: direct detoxification of reactive oxygen and reactive nitrogen species and indirectly by stimulating antioxidant enzymes while suppressing the activity of pro-oxidant enzymes. In addition to these well-described actions, melatonin also reportedly chelates transition metals, which are involved in the Fenton/Haber-Weiss reactions; in doing so, melatonin reduces the formation of the devastatingly toxic hydroxyl radical resulting in the reduction of oxidative stress. Melatonin's ubiquitous but unequal intracellular distribution, including its high concentrations in mitochondria, likely aid in its capacity to resist oxidative stress and cellular apoptosis. There is credible evidence to suggest that melatonin should be classified as a mitochondria-targeted antioxidant. Melatonin's capacity to prevent oxidative damage and the associated physiological debilitation is well documented in numerous experimental ischemia/reperfusion (hypoxia/reoxygenation) studies especially in the brain (stroke) and in the heart (heart attack). Melatonin, via its antiradical mechanisms, also reduces the toxicity of noxious prescription drugs and of methamphetamine, a drug of abuse. Experimental findings also indicate that melatonin renders treatment-resistant cancers sensitive to various therapeutic agents and may be useful, due to its multiple antioxidant actions, in especially delaying and perhaps treating a variety of age-related diseases and dehumanizing conditions. Melatonin has been effectively used to combat oxidative stress, inflammation and cellular apoptosis and to restore tissue function in a number of human trials; its efficacy supports its more extensive use in a wider variety of human studies. The uncommonly high-safety profile of melatonin also bolsters this conclusion. It is the current feeling of the authors that, in view of the widely diverse beneficial functions that have been reported for melatonin, these may be merely epiphenomena of the more fundamental, yet-to-be identified basic action(s) of this ancient molecule.