Role of biobanks in transplantation

Applications of transcriptomics in ischemia reperfusion research in lung transplantation

Ischemia-reperfusion (IR) injury contributes to primary graft dysfunction, a major cause of early mortality after lung transplantation. Transcriptomics uses high-throughput techniques to profile the RNA transcripts within a sample and provides a unique view of the mechanisms underlying various biological processes. This review aims to highlight the applications of transcriptomics in lung IR injury studies, which have thus far revealed inflammatory responses to be the major event activated by IR, identified potential biomarkers and therapeutic targets, and investigated the mechanisms of therapeutic interventions. Ex vivo lung perfusion, together with advanced bioinformatic and transcriptomic techniques, including single-cell RNA-sequencing, microRNA profiling, and multi-omics, continue to expand the capabilities of transcriptomics. In the future, the construction of biospecimen banks and the promotion of international collaborations among clinicians and researchers have the potential to advance our understanding of IR injury and improve the management of lung transplant recipients.

KiT-GENIE, the French genetic biobank of kidney transplantation

KiT-GENIE is a monocentric DNA biobank set up to consolidate the very rich and homogeneous DIVAT French cohort of kidney donors and recipients (D/R) in order to explore the molecular factors involved in kidney transplantation outcomes. We collected DNA samples for kidney transplantations performed in Nantes, and we leveraged GWAS genotyping data for securing high-quality genetic data with deep SNP and HLA annotations through imputations and for inferring D/R genetic ancestry. Overall, the biobank included 4217 individuals (n = 1945 D + 2,272 R, including 1969 D/R pairs), 7.4 M SNPs and over 200 clinical variables. KiT-GENIE represents an accurate snapshot of kidney transplantation clinical practice in Nantes between 2002 and 2018, with an enrichment in living kidney donors (17%) and recipients with focal segmental glomerulosclerosis (4%). Recipients were predominantly male (63%), of European ancestry (93%), with a mean age of 51yo and 86% experienced their first graft over the study period. D/R pairs were 93% from European ancestry, and 95% pairs exhibited at least one HLA allelic mismatch. The mean follow-up time was 6.7 years with a hindsight up to 25 years. Recipients experienced biopsy-proven rejection and graft loss for 16.6% and 21.3%, respectively. KiT-GENIE constitutes one of the largest kidney transplantation genetic cohorts worldwide to date. It includes homogeneous high-quality clinical and genetic data for donors and recipients, hence offering a unique opportunity to investigate immunogenetic and genetic factors, as well as donor-recipient interactions and mismatches involved in rejection, graft survival, primary disease recurrence and other comorbidities.

Markers of Bronchiolitis Obliterans Syndrome after Lung Transplant: Between Old Knowledge and Future Perspective

Bronchiolitis obliterans syndrome (BOS) is the most common form of CLAD and is characterized by airflow limitation and an obstructive spirometric pattern without high-resolution computed tomography (HRCT) evidence of parenchymal opacities. Computed tomography and microCT analysis show abundant small airway obstruction, starting from the fifth generation of airway branching and affecting up to 40-70% of airways. The pathogenesis of BOS remains unclear. It is a multifactorial syndrome that leads to pathological tissue changes and clinical manifestations. Because BOS is associated with the worst long-term survival in LTx patients, many studies are focused on the early identification of BOS. Markers may be useful for diagnosis and for understanding the molecular and immunological mechanisms involved in the onset of BOS. Diagnostic and predictive markers of BOS have also been investigated in various biological materials, such as blood, BAL, lung tissue and extracellular vesicles. The aim of this review was to evaluate the scientific literature on markers of BOS after lung transplant. We performed a systematic review to find all available data on potential prognostic and diagnostic markers of BOS.

Use of polyclonal antibodies in brain-dead donors in kidney transplantation

Objective. The objective of this study is to develop a therapeutic strategy for protecting grafts in order to improve the efficiency of kidney transplantation (KT) using polyclonal antibodies (pAbs) through elimination of activated forms of neutrophils, chemo- and cytokines from the donor’s bloodstream, and a decrease in the level of expression of adhesion molecules on the renal vascular endothelium at the pre-transplant stage.

Materials and methods. In 2017, we developed and for the first time applied a therapeutic strategy for ischemia-reperfusion injury (IRI) in a brain-dead donor (BDD). Given the limited time interval after brain death has been diagnosed, Timoglobulin (Sanofi Genzyme, France) was administered to the donor at a dose of 8 mg/kg intravenously for 6 hours. Before drug administration and immediately before the start of cold perfusion, a complete blood count and renal transplant biopsy were performed. The study group included 10 BDDs (mean age 39.3 ± 4.4 years) who received anti-thymocyte globulin (ATG). The comparison group included 10 BDDs (mean age 38.5 ± 4.3 years) who did not undergo the new strategy. Donor kidneys were transplanted to 40 recipients (average age 47.5 ± 4.3 years), who were also divided into 2 groups, depending on the graft received (with and without ATG). At the organ donation center, a biobank of specimens from donors of various categories, including those using the IRI therapeutic strategy and recipients for retrospective assessment of the effectiveness of pAbs, was formed.

Results. Clinical blood test results show that in the ATG group, there was stable leukopenia (neutropenia and lymphopenia) of 1.46 ± 0.18x109/l. Fifteen (75%) recipients of kidneys obtained from donors with ATG had immediate graft function; in the control group – 10 (50%) recipients.

Conclusion. Data obtained testify to the prospects of implementing the proposed strategy in clinical practice, which will improve the quality of the resulting grafts and their suitability for subsequent transplantation, prolong graft functioning due to elimination of leukocytes as a factor of IRI, prevention of early allograft nephropathy, increase in the donor pool by using expanded criteria donors (ECDs).

Biobank as a key component of supporting research in phthisiology and infectious diseases

Conducting fundamental and clinical research in the field of tuberculosis is an important step towards reducing related morbidity and mortality, but access to a sufficient number of high-quality samples required for research is an unsolved problem in Russia. This review is devoted to biobanking as a key component of modern research in personalized medicine, as well as to the status and prospects for developing this area in phthisiology and infectious diseases combined with tuberculosis.

Prognostic value of endogenous and exogenous metabolites in liver transplantation

Liver transplantation has been widely accepted as an effective intervention for end-stage liver diseases and early hepatocellular carcinomas. However, a variety of postoperative complications and adverse reactions have baffled medical staff and patients. Currently, transplantation monitoring relies primarily on nonspecific biochemical tests, whereas diagnosis of multiple complications depends on invasive pathological examination. Therefore, a noninvasive monitoring method with high selectivity and specificity is desperately needed. This review summarized the potential of endogenous small-molecule metabolites as biomarkers for assessing graft function, ischemia-reperfusion injury and liver rejection. Exogenous metabolites, mainly those immunosuppressive agents with high intra- and inter-individual variability, were also discussed for transplantation monitoring.

Barriers and Advances in Kidney Preservation

Despite the fact that a significant fraction of kidney graft dysfunctions observed after transplantation is due to ischemia-reperfusion injuries, there is still no clear consensus regarding optimal kidney preservation strategy. This stems directly from the fact that as of yet, the mechanisms underlying ischemia-reperfusion injury are poorly defined, and the role of each preservation parameter is not clearly outlined. In the meantime, as donor demography changes, organ quality is decreasing which directly increases the rate of poor outcome. This situation has an impact on clinical guidelines and impedes their possible harmonization in the transplant community, which has to move towards changing organ preservation paradigms: new concepts must emerge and the definition of a new range of adapted preservation method is of paramount importance. This review presents existing barriers in transplantation (e.g., temperature adjustment and adequate protocol, interest for oxygen addition during preservation, and clear procedure for organ perfusion during machine preservation), discusses the development of novel strategies to overcome them, and exposes the importance of identifying reliable biomarkers to monitor graft quality and predict short and long-term outcomes. Finally, perspectives in therapeutic strategies will also be presented, such as those based on stem cells and their derivatives and innovative models on which they would need to be properly tested.