Cadaveric renal allograft at the time of implantation has the similar immunological features with the rejecting allograft

Innate inflammatory gene expression profiling in potential brain-dead donors: detailed investigation of the effect of common corticosteroid therapy

Our study aimed to assess the influence of common methylprednisolone therapy on innate inflammatory factors in potential brain-dead organ donors (BDDs). The study groups consisted of 50 potential BDDs who received 15 mg/kg/d methylprednisolone and 25 live organ donors (LDs) as control group. Innate immunity gene expression profiling was performed by RT-PCR array. Soluble serum cytokines and chemokines, complement components, heat shock protein 70 (HSP70) and high mobility group box-1 (HMGB1) were measured by ELISA. Surface expression of TLR2 and TLR4 were determined using flow cytometry. Gene expression profiling revealed up-regulation of TLRs 1, 2, 4, 5, 6, 7 and 8, MYD88, NF-κB, NF-κB1A, IRAK1, STAT3, JAK2, TNF-α, IL-1β, CD86 and CD14 in the BDD group. Remarkably, the serum levels of C-reactive protein and HSP70 were considerably higher in the BDD group. In addition, serum amounts of IL-1β, IL-6, TNF-α, HMGB1, HSP70, C3a and C5a, but not IL-8, sCD86 or monocyte chemoattractant protein-1, were significantly increased in the BDD group. Significant differences were observed in flow cytometry analysis of TLR2 and TLR4 between the two groups. In summary, common methylprednisolone therapy in BDDs did not adequately reduce systemic inflammation, which could be due to inadequate doses or inefficient impact on other inflammatory-inducing pathways, for example oxidative stress or production of damage-associated molecules.

Effects of brain death on organ quality and transplant outcome

The inferiority of organs from brain dead donors is reflected by impaired graft survival and patient outcome. Brain death effects hemodynamic stability, hormonal changes, and neuroimmunologic effects and unleashes a cascade of inflammatory events. Despite considerable efforts in experimental and clinical research, most of the mechanisms linked to brain death are only appreciated on a descriptive level. This overview presents our current understanding of the pathophysiology and consequences of brain death on organ injury and summarizes available therapeutic interventions.

The influence of brain death on donor liver and the potential mechanisms of protective intervention

Brain-dead donors have become one of the main sources of organs for transplantation in Western countries. The quality of donor organs is closely related to the outcome of the transplantation. Experimental studies have confirmed the inferior graft survival of livers from brain-dead donors compared with those from living donors. Studies conducted in the past 10 years have shown that brain death is associated with effects on the decreased donor organ quality. However, whether the decrease in the viability of donor organs is caused by brain death or by the events before and after brain death remains uncertain. The purpose of this review is to introduce the advances and controversies regarding the influence of brain death on the viability of donor livers and to summarize the mechanisms of the different protective interventions for donor livers.

The influence of brain death on donor liver and the potential mechanisms of protective intervention

Brain-dead donors have become one of the main sources of organs for transplantation in Western countries. The quality of donor organs is closely related to the outcome of the transplantation. Experimental studies have confirmed the inferior graft survival of livers from brain-dead donors compared with those from living donors. Studies conducted in the past 10 years have shown that brain death is associated with effects on the decreased donor organ quality. However, whether the decrease in the viability of donor organs is caused by brain death or by the events before and after brain death remains uncertain. The purpose of this review is to introduce the advances and controversies regarding the influence of brain death on the viability of donor livers and to summarize the mechanisms of the different protective interventions for donor livers.

Systemic inflammation in the brain-dead organ donor

Brain death itself impairs organ function in the potential donor, thereby limiting the number of suitable organs for transplantation. In addition, graft survival of kidneys obtained from brain-dead (BD) donors is inferior to that of kidneys obtained from living donors. Experimental studies confirm an inferior graft survival for the heart, liver and lungs from BD compared with living donors. The mechanism underlying the deteriorating effect of brain death on the organs has not yet been fully established. We know that brain death triggers massive circulatory, hormonal and metabolic changes. Moreover, the past 10 years have produced evidence that brain death is associated with a systemic inflammatory response. However, it remains uncertain whether the inflammation is induced by brain death itself or by events before and after becoming BD. The purpose of this study is to discuss the risk factors associated with brain death in general and the inflammatory response in the organs in particular. Special attention will be paid to the heart, lung, liver and kidney and evidence will be presented from clinical and experimental studies.

Cytokine gene expression in kidney allograft biopsies after donor brain death and ischemia-reperfusion injury using in situ reverse-transcription polymerase chain reaction analysis

BACKGROUND

This study focuses on the cytokine genes expression after brain-death, ischemia-reperfusion injury, and during allograft rejection.

METHODS

A total of 49 needle core biopsies from kidney transplant recipients, performed before and during transplantation procedures were studied. The first biopsy was taken during procurement of the organ, the second after cold ischemia, and the third after approximately 30 min of reperfusion. We also assessed 34 allograft biopsies obtained during acute rejection. Tubular and glomerular expression of interferon (IFN)-gamma, transforming growth factor (TGF)-beta1, platelet-desired growth factor-B (PDGF-B), interleukin (IL)-2, IL-6, IL-10 mRNA was analyzed with reverse-transcription polymerase chain reaction (RT-PCR) in situ technique, which allows to detect a few copies of the target gene without destruction of the tissue architecture.

RESULTS

Compared with normal kidney tissue from living donor, high gene expression of IFN-gamma, TGF-beta1, PDGF-B, IL-2, IL-6, and IL-10 was detected in all procurement specimens. After reperfusion gene expressions of IL-2, IL-6, and IL-10 were significantly upregulated in renal tubules compared to biopsies taken after cold ischemia. The gene expression of IFN-gamma, TGF-beta1, and PDGF-B remained stable after organ procurement, during cold ischemia, and after reperfusion. Gene expression of IFN-gamma, IL-2, IL-6, IL-10, and PDGF-B in procurement biopsies, as well as in those taken after cold ischemia and reperfusion, were significantly higher than during the period of acute rejection.

CONCLUSION

The data presented herein strongly point out the importance of the immunological and morphological injury that occurs before and during transplantation. The increase of inflammatory response after brain death is important for further stimulation of the immune response and long-term kidney survival.

Brain death activates donor organs and is associated with a worse I/R injury after liver transplantation

The majority of transplants are derived from donors who suffered from brain injury. There is evidence that brain death causes inflammatory changes in the donor. To define the impact of brain death, we evaluated the gene expression of cytokines in human brain dead and ideal living donors and compared these data to organ function following transplantation. Hepatic tissues from brain dead (n = 32) and living donors (n = 26) were collected at the time of donor laparotomy. Additional biopsies were performed before organ preservation, at the time of transplantation and one hour after reperfusion. Cytokines were assessed by real-time reverse transcriptase-polymerase chain reaction (RT-PCR) and cytometric bead array. Additionally, immunohistological analysis of tissue specimens was performed. Inflammatory cytokines including IL-6, IL-10, TNF-alpha, TGF-beta and MIP-1alpha were significantly higher in brain dead donors immediately after laparotomy compared to living donors. Cellular infiltrates significantly increased in parallel to the soluble cytokines IL-6 and IL-10. Enhanced immune activation in brain dead donors was reflected by a deteriorated I/R injury proven by elevated alanin-amino-transferase (ALT), aspartat-amino-transferase (AST) and bilirubin levels, increased rates of acute rejection and primary nonfunction. Based on our clinical data, we demonstrate that brain death and the events that precede it are associated with a significant upregulation of inflammatory cytokines and lead to a worse ischemia/reperfusion injury after transplantation.

Does Donor Brain Death Influence Acute Vascular Rejection in the Kidney Transplant?

BACKGROUND

There is increasing experimental evidence to suggest that donor brain death enhances susceptibility to early inflammatory responses such as acute rejection in the kidney transplant. The aim of the present study was to establish whether the injury induced or aggravated by donor brain death could exert an effect on recipient immunologic tolerance by comparing data from patients receiving a kidney from non-heart-beating donors (NHBD) or from brain-dead donors (BDD).

METHODS

We reviewed data corresponding to 372 renal transplants performed from January 1996 to May 2002. The data were stratified according to donor type as 197 (53%) brain-dead and 175 (47%) non-heart-beating donors, and the two groups were compared in terms of acute vascular rejection by Cox's regression analysis.

RESULTS

The rate of vascular rejection was 28% in the BDD group and 21.7% in the NHBD (P=0.10). The following predictive variables for acute vascular rejection were established: brain death [RR 1.77 (95% CI 1.06-3.18)], presence of delayed graft function [RR 3.33 (1.99-5.55)], previous transplant [RR 2.35 (1.34-4.13)], recipient age under 60 years [RR 1.86 (0.99-2.28)], female recipient [RR 1.50 (0.99-2.28)], cerebrovascular disease as cause of donor death [RR 1.72 (1.02-2.91)], and triple therapy as immunosuppressive treatment.

CONCLUSION

Donor brain death could be a risk factor for the development of vascular rejection in kidney recipients. This process could affect the quality of the graft and host alloresponsiveness. Delayed graft function in transplants from dead brain donors could be a reflection of severe autonomic storm, leading to a higher incidence of vascular rejection in these patients.

Cytokine gene expression in kidney allograft donor biopsies after cold ischemia and reperfusion using in situ RT-PCR analysis

It was previously reported that ischemia-reperfusion injury initiates an inflammatory response and may significantly affect the transplanted organ function. The aim of this study was to assess changes of intragraft cytokine mRNA expression in kidneys after cold ischemia (CI) and following reperfusion. We examined mRNA of a product of activated T lymphocytes (IFN-gamma) and a monocyte product (IL-6). Eleven kidneys were transplanted after CI time ranging from 16 to 39 hours. Renal needle core biopsies were obtained from donors after cold ischemia and approximately after 20 minutes of reperfusion. Tubular and glomerular expression of IFN-gamma and IL-6 mRNA were assessed using semiquantitative evaluation of the RT-PCR in situ. After reperfusion an intense increase of IL-6 mRNA expression was observed in four specimens, a slight increase was noticed in five specimens, and a very slight decrease in two specimens. Changes in IL-6 mRNA expression were limited only to tubules. In contrast, the glomerular and tubular mRNA expression of IFN-gamma and glomerular of IL-6 remained stable. Mean CI time for patients with an intense increase was higher than for patients with a slight increase and with the decrease of IL-6 mRNA expression (32.0 +/- 6.8 vs 25.2 +/- 7.3 and 26.0 +/- 5.7 hours). Our results suggest that early inflammatory changes at the time of implantation of renal allografts depends mainly on monocyte/macrophage-associated products. The observed intensity of their expression in tubules was connected to longer CI time.

Differential early posttransplant cytokine responses in living and cadaver donor renal allografts

BACKGROUND

Differences in early posttransplant immunologic responses between living donor (LDT) and cadaver donor transplant (CDT) recipients have not been thoroughly studied. This is the first study comparing lymphocyte subpopulations and plasma levels of different cytokines, soluble cytokine receptors, cytokine receptor antagonists, and neopterin during the first 2 posttransplant weeks.

PATIENTS AND METHODS

Lymphocyte subpopulations (CD3, CD4, CD8, CD16, CD19, and CD25) and plasma levels of soluble (s) interleukin(IL)-1 receptor antagonist (RA), IL-2, sIL-2R, IL-3, IL-4, IL-6, sIL-6R, IL-8, IL-10, transforming growth factor-beta(2), tumor necrosis factor-alpha, interferon-gamma, and neopterin were studied in 52 CDT and 33 LDT recipients 1 to 2, 4 to 6, and 8 to 10 days after transplantation.

RESULTS

The most impressive finding was a consistently higher neopterin plasma level in CDT than LDT recipients. Although plasma neopterin decreased during the second posttransplant week in both groups (CDT, P = 0.0001; LDT, P = 0.001), the difference in plasma neopterin levels 8-10 days after transplantation was highly significant (P = 0.005). In contrast, LDT had consistently higher sIL-1RA plasma levels during the first 2 posttransplant weeks. Whereas sIL-1RA plasma levels decreased in both groups during the first posttransplant week (CDT, P = 0.001; LDT, P = 0.005), they increased during the second posttransplant week in LDT (P = 0.02) but remained stable and low in CDT recipients. Eight to ten days after transplantation, the difference was highly significant (P = 0.002).

CONCLUSION

These data suggest that transplantation of CDT is associated with strong monocyte-macrophage activation with consistently high neopterin plasma levels, whereas the effect of inflammatory cytokines seems to be down-regulated in LDT recipients by an increased release of antiinflammatory sIL-1RA.

Pre-transplant Th1 and post-transplant Th2 cytokine patterns are associated with early acute rejection in renal transplant recipients

In this retrospective study, we tried to define pre- and post-transplant immunological parameters that identify patients at risk for early acute rejection. Lymphocyte subpopulations and plasma levels of cytokines and neopterin were determined pre- and post-transplant in 32 renal transplant recipients with biopsy-proven early acute graft rejection. Recipients without early acute rejection served as controls. High pre-transplant interferon-gamma (IFN-gamma) plasma levels (p = 0.006), consistently high levels of neopterin early post-transplant (p = 0.008), a post-transplant switch from a Th1 to a Th2 cytokine pattern with decreasing IFN-gamma (p = 0.02), low CD8+ lymphocyte counts (p = 0.006) and consistently high CD19+ B lymphocyte counts were associated with acute rejection. Our data suggest that patients with a pre-transplant Th1 and an early post-transplant Th2 cytokine pattern are pre-disposed for early acute rejection.

Ischemia-reperfusion-induced lung injury

Ischemia-reperfusion-induced lung injury is characterized by nonspecific alveolar damage, lung edema, and hypoxemia occurring within 72 hours after lung transplantation. The most severe form may lead to primary graft failure and remains a significant cause of morbidity and mortality after lung transplantation. Over the past decade, better understanding of the mechanisms of ischemia-reperfusion injury, improvements in the technique of lung preservation, and the development of a new preservation solution specifically for the lung have been associated with a reduction in the incidence of primary graft failure from approximately 30 to 15% or less. Several strategies have also been introduced into clinical practice for the prevention and treatment of ischemia-reperfusion-induced lung injury with various degrees of success. However, only three randomized, double-blinded, placebo-controlled trials on ischemia-reperfusion-induced lung injury have been reported in the literature. In the future, the development of new agents and their application in prospective clinical trials are to be expected to prevent the occurrence of this potentially devastating complication and to further improve the success of lung transplantation.

The interleukin-6/interleukin-6-receptor system is activated in donor hearts

OBJECTIVES

To assess the potential of the donor heart to respond to interleukin-6 (IL6), the present study investigated the expression of IL6 receptor components in the myocardium of donor hearts before transplantation.

BACKGROUND

Donor heart dysfunction early after transplantation has been associated with the cytokine storm after donor brain death. Proinflammatory cytokines are thought to play a central role in this process. Interleukin-6 is of specific interest because it has been associated with cardiac allograft dysfunction and is related to an impaired prognosis. Its action requires expression of the specific IL6 receptor (IL6R), and the common signal transducer of the IL6 family glycoprotein 130 (gp130) in the donor heart.

METHODS

The activation of IL6, IL6R and gp130 messenger ribonucleic acid (mRNA) and protein was studied via reverse transcription-polymerase chain reaction (RT-PCR) and immunohistology in donor hearts (n = 6) and compared with patients undergoing evaluation of ventricular arrhythmias (control, n = 9) or with advanced heart failure (n = 20).

RESULTS

Messenger RNA of IL6, IL6R and gp130 was strongly expressed in all chambers of donor hearts, whereas right ventricles of control patients did not show any expression (donor vs. control: p < 0.005). Right ventricles of failing hearts showed IL6, IL6R and gp130 mRNA levels comparable with those found in donor hearts. Immunohistochemistry paralleled the RT-PCR data on the protein level. While IL6 was mainly expressed by myocytes, both receptor components were preferentially found mainly on interstitial cells.

CONCLUSIONS

The expression of the IL6 receptor components in the donor heart before transplantation establishes the condition sine qua non for the response of the donor heart to circulating IL6. This mechanism may explain the close association of elevated IL6 serum levels to acute cardiac allograft dysfunction in the early perioperative period.