Evaluation of New Baskent University Preservation Solution for Kidney Graft During Cold Ischemia: Preliminary Experimental Animal Study

Contribution of Turkey in Liver Transplant Research: A Scopus Database Search

OBJECTIVES

Liver transplantation is considered the most effective treatment modality for end-stage liver failure. The first deceased donor liver transplant in Turkey was performed by Haberal and colleagues in 1988; in 2019, a total of 1776 livertransplant procedures were performed in Turkey. While these are well-known and documented facts, the scientific output of publications on liver transplantation from Turkey is unknown.This study aimed to analyze the contribution of Turkey in liver transplant global research.

MATERIALS AND METHODS

Publications from Turkey on liver transplantation were analyzed using the bibliometric study method. The following research parameters were analyzed: year of publication, institutions and authors, funding, themes, sample population, and methods. We used the Scopus database to research key words containing "liver" or "hepatic"and"transplantation" in the titles, abstracts, and key words. Among duplications or multiple results, only 1 publication was included in the study. Data were analyzed by quantitative and qualitative methods.

RESULTS

We identified 45 763 publications on liver transplant. Most of the publications were in the field of medicine (93.48%). Turkey ranked fourteenth with 843 publications. The top productive affiliation was Başkent University, and the most productive author was Prof. Haberal.

CONCLUSIONS

Among countries, Turkey had the most living donor liver transplants in 2019 and could serve as a modelto European countries for donor shortages. Although the United States performs 5 times more liver transplants than Turkey, their publications rate was almost 22 times more. Combining a workload of performing research and publishing along with transplant surgery is together hard to master. Although Turkey has valuable experiences and has opened frontiers in transplantation, publications need to keep up with their hard work and innovations.

Melatonin in preservation solutions prevents ischemic injury in rat kidneys

Transplantation is lifesaving and the most effective treatment for end-stage organ failure. The transplantation success depends on the functional preservation of organs prior to transplantation. Currently, the University of Wisconsin (UW) and histidine-tryptophan-ketoglutarate (HTK) are the most commonly used preservation solutions. Despite intensive efforts, the functional preservation of solid organs prior to transplantation is limited to hours. In this study, we modified the UW solution containing components from both the UW and HTK solutions and analyzed their tissue-protective effect against ischemic injury. The composition of the UW solution was changed by reducing hydroxyethyl starch concentration and adding Histidine/Histidine-HCl which is the main component of HTK solution. Additionally, the preservation solutions were supplemented with melatonin and glucosamine. The protective effects of the preservation solutions were assessed by biochemical and microscopical analysis at 2, 10, 24, and 72 h after preserving the rat kidneys with static cold storage. Lactate dehydrogenase (LDH) activity in preservation solutions was measured at 2, 10, 24, and 72. It was not detectable at 2 h of preservation in all groups and 10 h of preservation in modified UW+melatonin (mUW-m) and modified UW+glucosamine (mUW-g) groups. At the 72nd hour, the lowest LDH activity (0.91 IU/g (0.63–1.17)) was measured in the mUW-m group. In comparison to the UW group, histopathological damage score was low in modified UW (mUW), mUW-m, and mUW-g groups at 10, 24, and 72 hours. The mUW-m solution at low temperature was an effective and suitable solution to protect renal tissue for up to 72 h.

Liver Graft Hypothermic Static and Oxygenated Perfusion (HOPE) Strategies: A Mitochondrial Crossroads

Marginal liver grafts, such as steatotic livers and those from cardiac death donors, are highly vulnerable to ischemia-reperfusion injury that occurs in the complex route of the graft from "harvest to revascularization". Recently, several preservation methods have been developed to preserve liver grafts based on hypothermic static preservation and hypothermic oxygenated perfusion (HOPE) strategies, either combined or alone. However, their effects on mitochondrial functions and their relevance have not yet been fully investigated, especially if different preservation solutions/effluents are used. Ischemic liver graft damage is caused by oxygen deprivation conditions during cold storage that provoke alterations in mitochondrial integrity and function and energy metabolism breakdown. This review deals with the relevance of mitochondrial machinery in cold static preservation and how the mitochondrial respiration function through the accumulation of succinate at the end of cold ischemia is modulated by different preservation solutions such as IGL-2, HTK, and UW (gold-standard reference). IGL-2 increases mitochondrial integrity and function (ALDH2) when compared to UW and HTK. This mitochondrial protection by IGL-2 also extends to protective HOPE strategies when used as an effluent instead of Belzer MP. The transient oxygenation in HOPE sustains the mitochondrial machinery at basal levels and prevents, in part, the accumulation of energy metabolites such as succinate in contrast to those that occur in cold static preservation conditions. Additionally, several additives for combating oxygen deprivation and graft energy metabolism breakdown during hypothermic static preservation such as oxygen carriers, ozone, AMPK inducers, and mitochondrial UCP2 inhibitors, and whether they are or not to be combined with HOPE, are presented and discussed. Finally, we affirm that IGL-2 solution is suitable for protecting graft mitochondrial machinery and simplifying the complex logistics in clinical transplantation where traditional (static preservation) and innovative (HOPE) strategies may be combined. New mitochondrial markers are presented and discussed. The final goal is to take advantage of marginal livers to increase the pool of suitable organs and thereby shorten patient waiting lists at transplantation clinics.

Organ Preservation Solutions in Transplantation: A Literature Review

OBJECTIVES

Renal transplant with ABO-incompatible donors expands the donor pool. Earlier studies have focused the use of protocol biopsies in ABOincompatible transplant patients. Our study described outcomes of indication (for cause) renal biopsies and clinical outcomes in patients with ABO-incompatible renal transplant.

MATERIALS AND METHODS

This retrospective study included 164 patients from January 2012 to June 2019. Biochemical parameters, serial immunoglobulin G anti-ABO titers, and class I and II donor-specific antibody findings were obtained from hospital records, and renal graft biopsies were reviewed according to the Banff 2017 update.

RESULTS

We analyzed the results of 65 biopsies from 54 patients. Biopsy-proven acute antibody-mediated rejection (12.8%) was found to be more prevalent than acute cellular rejection (1.8%). Patients with antibodymediated rejection all had microvascular inflammation (g+ptc score of 2 or more, where g+ptc is the sum of the glomerulitis and peritubular capillaritis scores) and were positive for C4d. Acute tubular injury per se was seen in 10.3% of patients; 65% of these patients had C4d positivity in peritubular capillaries, and only 1 patient developed chronic active antibody-mediated rejection on follow-up. Patient and death-censored graft survival rates were 92% and 98% at 1 year after transplant and 88% and 91% at 3 years, respectively. Patients with an episode of antibody-mediated rejection had lower rates of patient (76.5%) and deathcensored graft survival (84.6%) at 1 year.

CONCLUSIONS

The microvascular inflammation score (g+ptc score of 2 or higher) is more reliable than diffuse C4d positivity to determine antibody-mediated rejection in ABO-incompatible transplants because diffuse C4d positivity may also be seen in etiologies unrelated to antibody-mediated rejection. Acute tubular injury with C4d positivity without microvascular injury does not confirm antibody-mediated rejection. We suggest that Banff classification be updated in ABOincompatible transplants to include diagnostic criteria for the diagnosis of antibody-mediated rejection.

Significant Improvement in Rat Kidney Cold Storage Using UW Organ Preservation Solution Supplemented With the Immediate-Acting PrC-210 Free Radical Scavenger

Ischemia-reperfusion injury, including injury from warm- and cold-ischemia (CI) organ storage, remains a significant problem for all solid organ transplants. Suppressing CI damage would reduce delayed graft function and increase the donor organ pool size. PrC-210 has demonstrated superior prevention of damage in several preclinical studies as an immediate-acting free-radical scavenger. Here, we describe its profound efficacy in suppressing CI injury in a rat kidney model.

Donor Age Amplifies the Detrimental Effects of Cold Ischemia Time on Long-Term Kidney Allograft Survival Independently of the Occurrence of Delayed Graft Function or Early Acute Rejection

OBJECTIVES

We investigated the influence of the interaction between donor age and cold ischemia time on allograft survival in the absence of delayed graft function, early acute rejection, or the combination of both.

MATERIALS AND METHODS

We conducted a retrospective analysis of a cohort of patients first transplanted with living-related and deceased-donor allografts between 2001 and 2016. Predictors included cold ischemia time, donor and recipient age and sex, body mass index, renal replacement therapy duration, cause of end-stage renal disease, HLA class I and II mismatches, panel of reactive antibodies score, donor creatinine concentration, development of delayed graft function, and biopsy-proven acute rejection. The response variable was time until return to renal replacement therapy. Patients who died with functioning allografts were censored at the time of death. Analyses included multivariate Cox proportional hazards regression.

RESULTS

The study included 498 patients followed for median of 4.1 years with median cold ischemia time of 17.0 hours. On multivariate analysis, allograft survival was negatively affected by the cold ischemia time-donor age interaction (P = .026), acute rejection (P = .043), delayed graft function (P = .001), and acute rejection combined with delayed graft function (P = .002). Restricted mean allograft survival times in patients who developed neither delayed graft function nor acute rejection decreased from 13.6 to 8.6 years when cold ischemia time increased from 12 to 36 hours and donor age increased from 30 to 60 years.

CONCLUSIONS

Allograft survival was negatively affected by donor age-cold ischemia time interaction independently of the development of delayed graft function, acute rejection, or their combination.