The role of inflammatory mediators (platelet activity,the number and origin of micro particles and levels of mitochondrial DNA) in patient with acute renal transplant rejection.

Although current immunosuppressive drug therapies are quite successful, acute
renal allograft rejection still occurs in approximately 20% of patients after
cadaveric renal transplantation and causes graft loss in up to 4% in the first
year after transplantation. In the AMC, 120 patients per year receive a kidney
transplant, of which ± 22% develop acute rejection. Episodes of acute rejection
often have a negative impact on long-term graft survival and are major
predictors of chronic allograft nephropathy, which is responsible for most
death-censored graft loss after the first year posttransplant. The lack of
non-invasive biomarkers for rejection makes it difficult to optimize
anti-rejection therapy for transplant recipients. At present, the diagnosis of
renal allograft rejection requires a renal biopsy. Clinical management of renal
transplant patients would be improved by the identification of non-invasive
markers of rejection that can be measured frequently.
Renal ischemia- reperfusion (I/R) injury is a major cause of acute renal
transplant rejection and delayed allograft function. I/R injury is a
consequence of a complex interplay between renal hemodynamics, tubular and
endothelial cell injury and inflammatory processes. Circulating microparticles
(MP), platelets and mitochondrial DNA (mtDNA) have been identified as important
inflammatory mediators. Hence, these factors might contribute to induce renal
inflammatory responses upon I/R that eventually might lead to allograft
rejection.
We therefore hypothesize that inflammatory factors as circulating (plasma)
platelet activity levels, MP numbers and the levels of plasma or urinary mtDNA
correlate to the occurrence and severity of acute renal transplant rejection
and renal outcome.

The objective of this study is to investigate the role of inflammatory
mediators (circulating platelet activity levels, MP numbers, and levels of
plasma/urinary mtDNA) to the occurrence and severity of acute rejection and
renal outcome.

This study will be a prospective longitudinal observational cohort study in the
Academic Medical Center, in which we will include the following individuals:
Renal transplant recipients from either heart beating, non-heart beating donors
and living donors .In these patients blood will be drawn and urine will be
collected routinely in order to monitor for clinical signs of acute transplant
rejection. Depending on the clinical parameters (creatinine and urea levels in
plasma and urine) patients will undergo an indicative biopsy to confirm acute
rejection, or a protocol biopsy, which will be in part of the current research
protocol.
Patients are then divided into two groups:
1. Patients with clinical signs of acute rejection (according to blood and
urine parameters and the indicative biopsy) (n=11)
2. Patients without clinical signs of acute rejection (according to blood and
urine parameters and the protocol biopsy in part of the current
research protocol) (n=44)
Furthermore, a group of healthy individuals (n=10) will be included to
determine basal levels of inflammatory mediators in blood and urine.

Group 1&2

As part of standard care, blood is drawn and urine is collected for monitoring
renal functional parameters and graft function.
This will occur in: all patients (group 1 & 2) in the first week post
transplantation (at T=0); in patients (group 1) with signs of acute rejection
in which the indicative biopsy confirms acute transplant rejection (at T=X), in
patients without signs of acute rejection (group 2) which, undergo a protocol
biopsy (at T=6).

In addition, blood and urine will be collected 12 months (T=12) post
transplantation from both group 1 and 2,
For the purposes of this study 3 additional vials of blood (each 9mL) will be
drawn at all indicated time points.
To prevent unwanted activation of platelets and/or mitochondria, the required
additional blood will be collected into citrate vials.
Urine (1 mL) will be collected from the catheter in the first week post
transplantation and from the urine portion which is collected at all indicated
time points.
There are no additional interventions needed for this study

Healthy individuals

Blood will be drawn and urine will be collected from healthy volunteers to
asses basal levels of inflammatory mediators in blood and urine. In order to
determine the individual variance of these basal levels, blood will be drawn at
three time points: T=0, T= 6 and T=12 months.

All patients included in the study will receive standard care and medication.
As part of postoperative procedure, blood is drawn and urine is collected
routinely in the first week, after 6 months and 12 months post transplantation
in order to monitor renal functional parameters and graft recovery. Depending
on clinical signs of acute rejection (increased creatinine and urea plasma
levels or the development of proteinuria) an indicative biopsy will be taken to
confirm acute transplant rejection as part of good clinical practice.
Furthermore, as part of a current research protocol, a scheduled renal
transplant biopsy will be performed 6 months posttransplantation in order to
monitor graft condition. At the time of either biopsy, in the first week after
transplantation, at 6 and 12 months hereafter, 3 additional vials of blood
(each 9 mL) will be drawn and one sample of urine will be collected from the
patients.

Besides the donation of an additional 27 ml of peripheral blood (the cumulative
amount for the total study period of a year), no additional intervention is
necessary for the patients that will be included in this study. Hence, to our
opinion no unwanted or unpleasant side effects might occur. In addition, this
study will not require more time and will not modify the standard treatment of
enrolled patients.
Blood drawing will be exerted by professional nurses and physicians and will be
incorporated in the bloodsampling for clinical purposes. In this perspective,
no risks are associated with the participation of patients to this study.

A participating patient will not directly benefit from this observational
study. However, patients and volunteers might assess satisfaction of helping
others by contributing to medical knowledge, or helping to identify possible
new treatments. More knowledge about the possible correlation between platelet
activity/ number and origin of micro particles and the occurrence and severity
of acute renal transplant rejection, could be beneficial for future renal
transplant recipients characterized with acute rejection,