Acute cellular rejection (ACR) occurs in 10% of renal allograft recipients and is characterized by leukocyte infiltration as observed in needle biopsies. ACR onset is subject to several risk... Show moreAcute cellular rejection (ACR) occurs in 10% of renal allograft recipients and is characterized by leukocyte infiltration as observed in needle biopsies. ACR onset is subject to several risk factors, including delayed graft function (DGF). As the impact of DGF on the etiology of ACR remains unclear, this study analyzed the association between presence of leukocyte subsets and ACR onset, in DCD kidney biopsies with extensive DGF following transplantation. Immunohistochemical analysis of protocol biopsies taken 10 days after kidney transplantation revealed that patients with high levels of renal CD163+ macrophages have a decreased risk (OR = 0.021, P = 0.008) for ACR in the first 6 months after transplantation. In pre-transplant biopsies of a comparable DCD cohort, with >80% DGF, presence of donor CD163+ macrophages showed no effect on ACR risk. Therefore, leukocyte infiltrate present during the inflammatory response at the time of DGF may contain anti-inflammatory macrophages that exert a protective effect against ACR development. Show less
This thesis demonstrates that kidneys from DCD donors can be fully embraced, and that the perception of DCD kidney transplantation being inferior to DBD kidney transplantation – mainly motivated by... Show moreThis thesis demonstrates that kidneys from DCD donors can be fully embraced, and that the perception of DCD kidney transplantation being inferior to DBD kidney transplantation – mainly motivated by concerns regarding high incidences of DGF and EGL – is no longer justified. One explanation for this phenomenon is that outcomes of transplanted DCD kidneys have improved over time, with a similar incidence of EGL following DBD and DCD kidney transplantation in the current era. Another explanation is that both donor types have different biological responses to DGF: whilst DGF severely impacts on DBD graft survival, DGF has no impact on DCD graft survival. This difference relates to donor type-specific regulation of resilience and pro-inflammatory pathways benefitting the DCD graft and its outcomes. As such, the persistent high incidence of DGF in DCD grafts should not be regarded an impediment toward the use of these donor kidneys.This thesis additionally explores a series of physiological and methodological contrasts between preclinical and clinical I/R injury, that all may contribute to the impaired translatability of preclinical studies in clinical practice. Awareness of these pitfalls may help to improve study designs in future research, bringing us one step closer towards bridging the translational gap. Show less
In this thesis, we focus on recipients of donation after circulatory death (DCD) kidneys in the first months after transplantation. DCD kidney transplant recipients have an increased risk of early... Show moreIn this thesis, we focus on recipients of donation after circulatory death (DCD) kidneys in the first months after transplantation. DCD kidney transplant recipients have an increased risk of early complications post transplantation such as acute rejection and delayed graft function (DGF). A sensitive and specific biomarker to monitor the occurrence of an acute rejection episode or (the resolution of) DGF is unfortunately not available to date. For a definite diagnosis, a kidney allograft biopsy remains the so-called ‘golden standard’. A percutaneous kidney biopsy is, however, an invasive procedure with a risk of bleeding complications. Guidance in daily clinical practice by a simple but reliable marker is needed, and can help to monitor regular resolution of DGF and/or identify intercurrent problems such as acute rejection episodes. In the current thesis we investigated risk factors of acute rejection and DGF. In addition, the most promising biomarkers of kidney injury according to current literature (i.e. KIM-1, NGAL, TIMP-2, IGFBP7) were investigated in the prediction of DGF and acute rejection. Furthermore, we used an alternative approach in the search for biomarkers by analyzing smaller molecules with Nuclear Magnetic Resonance (NMR) spectroscopy.We still have not found the ‘perfect’ biomarker to monitor acute rejection DGF after kidney transplantation, however of all biomarkers investigated TIMP-2 showed the greatest potential. Using the approach of metabolomics, we were able to identify new biomarkers. Further studies are needed to confirm and validate these results and evaluate their usefulness in daily clinical practice. Show less
Introduction: The success of pancreas transplantation, in combination with a stable number of available allografts has resulted in an increasing waiting list. This study investigated donor... Show moreIntroduction: The success of pancreas transplantation, in combination with a stable number of available allografts has resulted in an increasing waiting list. This study investigated donor potential by expanding age and Body Mass Index (BMI) criteria.Methods: All reported donors in the Netherlands between 2013 and 2017 were analysed. Risk assessment of extended criteria donors was done by in-depth analysis of donor reports and calculation of the Pancreas Donor Risk Index (PDRI). The PDRI of these extended criteria donors was compared to standard criteria donors to evaluate the increased risk on graft failure.Results: A total of 1273 donors were reported. Of these donors, 405 donors were reported as pancreas donor, of which 93 (23%) pancreata were transplanted. Extending age criterion with 5 years could result in additional 40 Donation after Brain Death donors and 37 Donation after Circulatory Death donors reported. In 24 (31%) extended age criteria donors the PDRI was below the upper limit of currently transplanted pancreata. Extending BMI criteria to 35 kg/m(2) could result in an additional 19 (6%) donors reported.Conclusions: Extending BMI criteria could result in a slight increase of reported donors. Extending age criteria increased significantly the number of reported donors. In 24 (31%) of the older donors the PDRI showed a reduced risk compared to currently transplanted pancreata. This study suggest that, if other risk factors are absent, pancreata of extended age and/or BMI criteria donors should be considered for transplantation. (C) 2019 IAP and EPC. Published by Elsevier B.V. All rights reserved. Show less
Pancreas transplantation is the only long-lasting curative option patients with type 1 diabetes mellitus. During the last 50 years, it has evolved from an experimental procedure to an accepted... Show morePancreas transplantation is the only long-lasting curative option patients with type 1 diabetes mellitus. During the last 50 years, it has evolved from an experimental procedure to an accepted treatment. For patients suffering from diabetes mellitus induced end-stage renal disease, a simultaneous pancreas-kidney transplantation is the best option. Due to increased experience, the indications for transplantation have been expanded, causing waiting lists to increase. To match the increasing demand, transplant professionals are forced to accept higher risk donor organs. This thesis investigates those risks and aims to quantify the risk in donor risk indices. Those risk indices were also investigated in this thesis. Furthermore, solitary risk factors for outcome were investigated. There appears to be a significant association between center volume and outcome: high volume center have better results than low volume centers, despite accepting higher risk donor organs. Another risk factor that was investigated was donation after circulatory death (DCD) pancreas transplantation. It showed that DCD pancreas transplantation is a feasible option to expand the donor pool. Show less
Rijn, R. van; Berg, A.P. van den; Erdmann, J.I.; Heaton, N.; Hoek, B. van; Jonge, J. de; ... ; Porte, R.J. 2019
In this thesis the impact of donor and recipient risk factors and the development of risk models in liver transplantation was investigated. These models can be used for multiple purposes, including... Show moreIn this thesis the impact of donor and recipient risk factors and the development of risk models in liver transplantation was investigated. These models can be used for multiple purposes, including risk indication, outcome prediction and benchmarking between transplant centers. As such, several steps have been made towards evidence-based liver allocation and proper selection of liver allografts in times of organ shortage and the current system of severitybased liver allocation (by MELD the score). Further refinement of these models is necessary in order to optimize donor to recipient matching and achieve an objective, transparent and well-informed system of liver allocation. Altogether, the efforts made here to improve waitlist and transplantation outcomes, are meant for the individual transplant candidate on the liver transplant waitlist and as a whole, for the transplant community. Show less
