[Machine perfusion: new opportunities in abdominal organ transplantation]. / Szervkonzerválás gépi perfúzióval: új lehetoségek a hasi szervek transzplantációjában.

Machine perfusion of marginal grafts might be a possible solution to organ shortage and a promising tool for reducing waiting list morbidity and mortality. In recent years, optimizing the circumstances of organ preservation prior to implantation via machine perfusion has become a hot topic of research. Machine perfusion offers a platform for organ reconditioning, assessment of cell viability and function, pharmacological preconditioning, prolongation of preservation time (ischemia time) and finally reducing graft injury. The objective of the new technology is to increase the pool of transplantable organs safely. Multicentric prospective studies have been evaluating the short and long term outcomes of different methods, however, several questions still remain unanswered. This review summarizes the recent advances in the field of machine perfusion, focusing on preclinical and clinical results. Machine perfusion seems to be a new milestone in the modern era of solid organ transplantation. Orv Hetil. 2018; 159(46): 1882-1890.

Discovery of an L-alanine ester prodrug of the Hsp90 inhibitor, MPC-3100.

Various types of Hsp90 inhibitors have been and continue to undergo clinical investigation. One development candidate is the purine-based, synthetic Hsp90 inhibitor 1 (MPC-3100), which successfully completed a phase I clinical study. However, further clinical development of 1 was hindered by poor solubility and consequent formulation issues and promoted development of a more water soluble prodrug. Towards this end, numerous pro-moieties were explored in vitro and in vivo. These studies resulted in identification of L-alanine ester mesylate, 2i (MPC-0767), which exhibited improved aqueous solubility, adequate chemical stability, and rapid bioconversion without the need for solubilizing excipients. Based on improved physical characteristics and favorable PK and PD profiles, 2i mesylate was selected for further development. A convergent, scalable, chromatography-free synthesis for 2i mesylate was developed to support further clinical evaluation.

HLA antibody screening in kidney transplantation: current guidelines.

BACKGROUND: In organ transplantation, the introduction of the solid phase immunoassay technology radically changed the practice of antibody monitoring against human leukocyte antigens (HLA). PURPOSE: Precise identification of antibody specificities in complex sera of sensitized patients and monitoring of low levels of donor-specific HLA antibodies in the posttransplant phase became possible. However, at the same time, new technical problems and great variation emerged in the interpretation of test results, indicating a need for standardization. CONCLUSION: In May 2012, The Transplantation Society (TTS) recruited a panel of laboratory and clinical experts to discuss emerging testing and clinical management issues that are associated with antibody testing in organ transplantation. In this article, we provide a summary of the TTS recommendations formulated in this international effort on the standardization of antibody monitoring in kidney transplantation.

[Challenges of the modern antibody diagnostics in kidney transplantation]. / A modern antitestdiagnosztika kihívásai vesetranszplantáció során.

Overcoming antibody mediated rejection is of increasing interest in the field of transplantation immunology. The recipient's antibodies against the graft human leukocyte antigens are responsible for antibody mediated graft injury. Introduction of the solid phase immunoassay technology radically changed the monitoring practice of antibodies against human leukocyte antigens, and this has consequences both for pretransplant and posttransplant phases, though our knowledge about the clinical interpretation of the detected antibodies is limited. This integrating review reports recommendations and algorithms regarding the management of kidney transplant patients. The detection of complement activation combined with the solid phase techniques is a promising new approach in antibody testing. The C4d and especially the more sensitive C1q methods have the potential to answer pivotal questions about the clinical relevance of antibodies. Answering the questions that the applied new methods raised and reviewing the recommendations are needed to remain up to date with this dynamically developing field.

Oxygenated End-Hypothermic Machine Perfusion in Expanded Criteria Donor Kidney Transplant: A Randomized Clinical Trial.

Importance: Continuous hypothermic machine perfusion during organ preservation has a beneficial effect on graft function and survival in kidney transplant when compared with static cold storage (SCS). Objective: To compare the effect of short-term oxygenated hypothermic machine perfusion preservation (end-HMPo2) after SCS vs SCS alone on 1-year graft survival in expanded criteria donor kidneys from donors who are brain dead. Design, Setting, and Participants: In a prospective, randomized, multicenter trial, kidneys from expanded criteria donors were randomized to either SCS alone or SCS followed by end-HMPo2 prior to implantation with a minimum machine perfusion time of 120 minutes. Kidneys were randomized between January 2015 and May 2018, and analysis began May 2019. Analysis was intention to treat. Interventions: On randomization and before implantation, deceased donor kidneys were either kept on SCS or placed on HMPo2. Main Outcome and Measures: Primary end point was 1-year graft survival, with delayed graft function, primary nonfunction, acute rejection, estimated glomerular filtration rate, and patient survival as secondary end points. Results: Centers in 5 European countries randomized 305 kidneys (median [range] donor age, 64 [50-84] years), of which 262 kidneys (127 [48.5%] in the end-HMPo2 group vs 135 [51.5%] in the SCS group) were successfully transplanted. Median (range) cold ischemia time was 13.2 (5.1-28.7) hours in the end-HMPo2 group and 12.9 (4-29.2) hours in the SCS group; median (range) duration in the end-HMPo2 group was 4.7 (0.8-17.1) hours. One-year graft survival was 92.1% (n = 117) in the end-HMPo2 group vs 93.3% (n = 126) in the SCS group (95% CI, -7.5 to 5.1; P = .71). The secondary end point analysis showed no significant between-group differences for delayed graft function, primary nonfunction, estimated glomerular filtration rate, and acute rejection. Conclusions and Relevance: Reconditioning of expanded criteria donor kidneys from donors who are brain dead using end-HMPo2 after SCS does not improve graft survival or function compared with SCS alone. This study is underpowered owing to the high overall graft survival rate, limiting interpretation. Trial Registration: isrctn.org Identifier: ISRCTN63852508.

[New challenges of liver transplantation]. / A májtranszplantáció új kihívásai.

In the last decades, the results of liver transplantation have shown significant improvement. More patients are eligible for liver transplantation, while the indications are changing. The worldwide shortage of donor organs urges the profession for the development of new strategies. With rational extension of donor criteria, more precise organ allocation, personalized donation, living related donation, machine perfusion, and donation after cardiac death, liver transplantation is becoming available for more and more patients suffering from end stage liver disease. Hereby we summarize the new possibilities and challenges in the light of the Hungarian liver transplant program. Orv Hetil. 2019; 160(29): 1127-1135.

Association of Kidney Graft Loss With De Novo Produced Donor-Specific and Non-Donor-Specific HLA Antibodies Detected by Single Antigen Testing.

BACKGROUND: The association of donor-specific HLA antibodies (DSA) with kidney graft failure has been addressed previously; however, the majority of studies were based on small numbers of patients with graft failure. METHODS: We investigated 83 patients with failed kidney transplants for a possible association of de novo development and persistence or loss of pre-existing DSA with graft failure. Single Antigen Bead assay-detected DSA and non-DSA antibodies were compared between patients with graft loss and matched controls with functioning grafts. RESULTS: The incidence of weak de novo DSA or non-DSA at a mean fluorescence intensity of 500 or higher was higher in the graft loss than in the nonrejector group (76% vs 40%, P < 0.001). Because of the low number of patients developing de novo DSA, the DSA results did not reach statistical significance (only 22% of patients with graft loss developed de novo DSA). However, at all cutoffs, there was a significantly higher rate of graft loss in patients with de novo non-DSA. The incidence of strong pretransplant DSA that persist after transplantation was higher in the graft loss group (10% vs 1%, P = 0.034). When C1q-binding ability in sera of rejectors and nonrejectors with posttransplant de novo or persistent DSA was compared, none of the nonrejectors demonstrated C1q positivity, whereas 43% of patients with graft loss showed C1q-positive antibodies, although not necessarily donor-specific (P < 0.001). CONCLUSIONS: Our data show that the posttransplant presence of persisting or de novo HLA antibodies, especially if C1q binding, is associated with graft loss, even if the antibodies are not specific for mismatched donor HLA.

Discovery of (2S)-1-[4-(2-{6-amino-8-[(6-bromo-1,3-benzodioxol-5-yl)sulfanyl]-9H-purin-9-yl}ethyl)piperidin-1-yl]-2-hydroxypropan-1-one (MPC-3100), a purine-based Hsp90 inhibitor.

Modulation of Hsp90 (heat shock protein 90) function has been recognized as an attractive approach for cancer treatment, since many cancer cells depend on Hsp90 to maintain cellular homeostasis. This has spurred the search for small-molecule Hsp90 inhibitors. Here we describe our lead optimization studies centered on the purine-based Hsp90 inhibitor 28a containing a piperidine moiety at the purine N9 position. In this study, key SAR was established for the piperidine N-substituent and for the congeners of the 1,3-benzodioxole at C8. These efforts led to the identification of orally bioavailable 28g that exhibits good in vitro profiles and a characteristic molecular biomarker signature of Hsp90 inhibition both in vitro and in vivo. Favorable pharmacokinetic properties along with significant antitumor effects in multiple human cancer xenograft models led to the selection of 28g (MPC-3100) as a clinical candidate.

Discovery and SAR of methylated tetrahydropyranyl derivatives as inhibitors of isoprenylcysteine carboxyl methyltransferase (ICMT).

A series of tetrahydropyranyl (THP) derivatives has been developed as potent inhibitors of isoprenylcysteine carboxyl methyltransferase (ICMT) for use as anticancer agents. Structural modification of the submicromolar hit compound 3 led to the potent 3-methoxy substituted analogue 27. Further SAR development around the THP ring resulted in an additional 10-fold increase in potency, exemplified by analogue 75 with an IC(50) of 1.3 nM. Active and potent compounds demonstrated a dose-dependent increase in Ras cytosolic protein. Potent ICMT inhibitors also reduced cell viability in several cancer cell lines with growth inhibition (GI(50)) values ranging from 0.3 to >100 µM. However, none of the cellular effects observed using ICMT inhibitors were as pronounced as those resulting from a farnesyltransferase inhibitor.

Characterization of the cellular and antitumor effects of MPI-0479605, a small-molecule inhibitor of the mitotic kinase Mps1.

Mps1 is a dual specificity protein kinase that is essential for the bipolar attachment of chromosomes to the mitotic spindle and for maintaining the spindle assembly checkpoint until all chromosomes are properly attached. Mps1 is expressed at high levels during mitosis and is abundantly expressed in cancer cells. Disruption of Mps1 function induces aneuploidy and cell death. We report the identification of MPI-0479605, a potent and selective ATP competitive inhibitor of Mps1. Cells treated with MPI-0479605 undergo aberrant mitosis, resulting in aneuploidy and formation of micronuclei. In cells with wild-type p53, this promotes the induction of a postmitotic checkpoint characterized by the ATM- and RAD3-related-dependent activation of the p53-p21 pathway. In both wild-type and p53 mutant cells lines, there is a growth arrest and inhibition of DNA synthesis. Subsequently, cells undergo mitotic catastrophe and/or an apoptotic response. In xenograft models, MPI-0479605 inhibits tumor growth, suggesting that drugs targeting Mps1 may have utility as novel cancer therapeutics.