Cell adhesion molecules in clinical renal transplantation

Genetic association of interleukin-2, interleukin-4, interleukin-6, transforming growth factor-β, tumour necrosis factor-α and blood concentrations of calcineurin inhibitors in Turkish renal transplant patients

Cytokines are essential for the control of the immune response as most of the immunosuppressive drugs target cytokine production or their action. The calcineurin inhibitors (CNIs) cyclosporine (CsA) and tacrolimus are immunosuppressive drugs widely used after renal transplantation to prevent allograft rejection. They are characterized by large interindividual variability in their pharmacokinetics; therefore, monitoring their blood concentrations is important to predict their optimal dosage following transplantation. Calcineurin inhibitors inhibit the phosphatase activity of calcineurin, thereby suppressing the production of other cytokines such as transforming growth factor (TGF-β), tumour necrosis factor-α (TNF-α), interleukin (IL)-6, IL-2, and IL-4. The aim of this study was to investigate the relationship between polymorphisms of cytokines and blood concentrations of CNIs in renal transplant patients. The study included 53 CsA-treated renal transplant patients and 37 tacrolimus-treated renal transplant patients. Cytokine polymorphisms were analysed using polymerase chain reaction (PCR) sequence-specific primers with the cytokine CTS-PCR-sequence-specific primers Tray Kit; University of Heidelberg. Blood concentrations of CNIs were determined with Cloned Enzyme Donor Immunoassay (CEDIA) method. Patients with TC genotype of TGF-β at codon 10 had lower CsA blood concentrations than the TT and CC genotypes (P = 0.005) at 1 month in CsA treatment group. The ratio of blood concentration/dose of CsA for patients with TGF-β1-codon 10 TC genotype was lower than for patients with TT, CC genotypes, and the dose given to these patients was higher in the first month (P = 0.046). The ratio of blood concentration/dose of CsA for patients with IL-2-330 GG genotype was higher than for patients with GT, TT genotypes, and the dose given to these patients was lower at first month and sixth months (P = 0.043, P = 0.035 respectively). The tacrolimus blood concentrations were significantly higher in patients with the genotype GG of IL-2-330 (P = 0.012) at the third month. Patients who had the TC genotype TGF-β codon 10 had lower CsA blood concentrations and this group had higher acute rejection (P = 0.033). These results suggest that the genotyping for TGF-β-codon 10, IL-2-330 and IL-6-174 polymorphisms may help individualized immunosuppressive dosage regiments.

Plasmin administration during ex vivo lung perfusion ameliorates lung ischemia-reperfusion injury

BACKGROUND

Donor lung thrombus is considered a significant etiology for primary graft dysfunction (PGD). We hypothesized that thrombolysis in ex vivo lung perfusion (EVLP) before lung transplantation could alleviate ischemia-reperfusion injury (IRI), resulting in a decreased incidence of PGD.

METHODS

Rats were divided into control (n = 5), non-plasmin (n = 7) and plasmin (n = 7) groups. In the non-plasmin and plasmin groups, cardiac arrest was induced by withdrawal of ventilation without heparinization. After 120 minutes of warm ischemia, the lungs were ventilated and flushed. Hearts and both lungs were excised en bloc. The lungs were perfused and ventilated in the EVLP for 30 minutes, and plasmin or placebo was administered on EVLP initiation. The lungs were then stored at 4°C for 90 minutes and finally perfused with rat blood for 80 minutes. We assessed physiologic and histologic findings during reperfusion and the correlation between physiologic data during EVLP and after reperfusion.

RESULTS

Physiologic results were better in the plasmin group than in the non-plasmin group. The plasmin group lungs had fewer signs of histologic injury. Caspase-3 and -7 activity in the plasmin group was lower in the non-plasmin group. Pulmonary vascular resistance (PVR) during EVLP correlated with that at the end of reperfusion.

CONCLUSIONS

Plasmin administration during EVLP protected the donor lungs after reperfusion. We also found that several physiologic values in EVLP may be predictive markers of lung function after reperfusion.

Preventive Effects of a Natural Anti-Inflammatory Agent, Astragaloside IV, on Ischemic Acute Kidney Injury in Rats

This study investigated the anti-inflammatory effects of astragaloside IV(AS-IV) on ischemia/reperfusion (IR) induced acute kidney injury (AKI) in rats. Experimental model of ischemic AKI was induced in rats by bilateral renal artery clamp for 45 min followed by reperfusion of 12 h and 24 h, respectively. AS-IV was orally administered once a day to rats at 10 and 20 mg·kg⁻¹·d⁻¹ for 7 days prior to ischemia. AS-IV pretreatment significantly decreased serum urea, creatinine, and cystatin C levels at 12 h and 24 h of reperfusion in AKI rats. AS-IV pretreatment also ameliorated tubular damage and suppressed the phosphorylation of p65 subunit of NF-κB in AKI rats. Moreover, NF-κB and MPO activity as well as serum and tissue levels of TNF-α, MCP-1, and ICAM-1 were elevated in AKI rats. All of these abnormalities were prevented by AS-IV. Furthermore, AS-IV downregulated the mRNA expression of NF-κB, TNF-α, MCP-1, and ICAM-1 in AKI rats. These results suggest that AS-IV might be developed as a novel therapeutic approach to prevent ischemic AKI through inhibition of NF-κB mediated inflammatory genes expression.

The effects of Castanospermine, an oligosaccharide processing inhibitor, on mononuclear/endothelial cell binding and the expression of cell adhesion molecules

INTRODUCTION

In this study we aimed to determine whether Castanospermine, a transplant immunosuppressive agent, impaired mononuclear/endothelial cell binding and expression of their cell adhesion molecules.

METHODS

The binding of human umbilical vein endothelial cells with peripheral blood mononuclear cells was measured by a binding assay using Chromium 51 label; the membrane expression of cell adhesion molecules was measured by flow cytometry expressed as mean fluorescence intensity ratios.

RESULTS

Castanospermine decreased mononuclear/endothelial cell binding if and only if both cell types were treated with Castanospermine: this impairment occurred if endothelial cells were treated with a range of doses of Castanospermine and mononuclear cells were treated with a constant dose of Castanospermine (p<0.001 versus untreated p=0.978) or vice versa (p=0.004 versus untreated p=0.582). Upon human umbilical vein endothelial cells Castanospermine reduced the mean fluorescence intensity ratios of E-selectin (p=0.003), ICAM-1 (p<0.001), ICAM-2 (p=0.004) and PECAM-1 (p<0.001) but increased it for P-selectin (p<0.001). Upon peripheral blood mononuclear cells Castanospermine reduced the mean fluorescence intensity ratios of L-selectin (P<0.001), LFA-1α (p<0.001), VLA-4 (p<0.001), Mac-1 (P<0.001) and CR4 (p<0.001) but increased the mean fluorescence intensity ratios of PSGL-1 (p<0.001) and PECAM-1 (p=0.001). Similar changes in mean fluorescence intensity ratios were found in the subset of lymphocytes and monocytes but the reductions in LFA-1α and VLA-4 on lymphocytes and Mac-1 and CR4 on monocytes were greater.

CONCLUSIONS

The reduction in mononuclear/endothelial cell binding mediated by CAST and the reduction in expression of multiple cell adhesion molecules on these cell types help to explain the mechanism of its established immunosuppressive effect.

Genetic polymorphisms of inflammatory molecules in Tunisian kidney transplantation

As chemokines and adhesion molecules play major roles in the process by which leukocytes are recruited from the bloodstream into sites of inflammation, genetic variations in the production or activity of molecules may influence susceptibility to acute rejection episodes. This study sought to determine the impact of recipient monocyte chemoattractant protein-1 (MCP-1), chemokine receptor (CCR2, CCR5), and adhesion molecule (ICAM-1, PECAM-1 and L/E selectin) polymorphisms on acute rejection after renal transplantation. We selected 169 healthy blood donors and 173 renal transplant recipients for analysis according to the presence or absence of graft rejection in the first 30 days after transplantation. Using molecular methods DNA was genotyped for 11 polymorphisms of these inflammatory molecules genes. Results were stratified by the incidence of rejection episodes and by human leukocyte antigen (HLA) mismatching. No association was detected between adhesion molecule polymorphisms and the incidence of acute rejection episodes. However, a significant risk of acute renal loss was observed among HLA-identical recipients who possessed the CCR2-64I allele (odds ratio 0.24, 95% confidence interval, 0.05 to 1.06; P=.035). In conclusion, the observed association of CCR2-64I with acute rejection episodes should be added to the spectrum of immunogenetic factors known to be involved in renal allograft rejection.

Association of polymorphisms of interleukin-8, CXCR1, CXCR2, and selectin with allograft outcomes in kidney transplantation

BACKGROUND

Both chemokines and adhesion molecules mediate allograft rejection by recruiting leukocytes into the allograft. We investigated the association of six single nucleotide polymorphisms (SNPs) located in interleukin (IL)-8, CXCR1, CXCR2, and selectin with kidney allograft outcomes.

METHODS

The promoter regions of CXCR1 and CXCR2 were sequenced directly to find SNPs. Reporter gene assay was performed to determine the transcriptional activity of CXCR2 promoter polymorphisms. The association of SNPs in IL-8, CXCR1, CXCR2, and selectin with both acute rejection and estimated glomerular filtration rate at 1-year posttransplant was analyzed in 216 donor-recipient pairs of kidney transplantation.

RESULTS

The donor GA/AA genotypes of CXCR1 -2668G/A (rs2671222) were associated with increased risk for acute rejection even after adjusting for covariates such as gender, diabetes, preemptive transplantation, immunosuppressive regimen, relationship with the donor, and human leukocyte antigen mismatch (adjusted odds ratio 3.56; 95% confidence interval 1.37-9.27; P=0.009). Although the transcriptional activity of the CXCR2 variant promoter was 2.6-fold higher than that of the wild-type promoter (P=0.039), no significant association was observed between CXCR2 polymorphisms and kidney allograft outcomes. SNPs of IL-8, L-selectin, and E-selectin were not associated with kidney allograft outcomes.

CONCLUSION

The donor CXCR1 -2668 GA/AA genotypes were an independent risk factor for acute rejection in kidney transplantation.

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.

Mediators of inflammation in acute kidney injury

Acute kidney injury (AKI) remains to be an independent risk factor for mortality and morbidity. Inflammation is now believed to play a major role in the pathopathophysiology of AKI. It is hypothesized that in ischemia, sepsis and nephrotoxic models that the initial insult results in morphological and/or functional changes in vascular endothelial cells and/or in tubular epithelium. Then, leukocytes including neutrophils, macrophages, natural killer cells, and lymphocytes infiltrate into the injured kidneys. The injury induces the generation of inflammatory mediators like cytokines and chemokines by tubular and endothelial cells which contribute to the recruiting of leukocytes into the kidneys. Thus, inflammation has an important role in the initiation and extension phases of AKI. This review will focus on the mediators of inflammation contributing to the pathogenesis of AKI.

Circulating adhesion molecules and purine nucleotides during kidney allograft reperfusion

The impairment of organ function due to ischemia-reperfusion injury is still an important problem in solid organ transplantation. Numerous experimental and clinical studies of native organs have shown that ischemia-reperfusion constitutes an acute inflammatory process involving cell surface adhesion molecule expression. These markers are crucial for the recruitment and infiltration of effector cells into the postischemic tissue. Purines released by the postischemic tissue as the products of the degradation of high-energy nucleotides can be regarded as markers of disturbed energy metabolism. The aim of this study was to examine the correlation between circulating adhesion molecules and purine metabolites in graft renal vein plasma during 49 cases of kidney reperfusion. E-selectin, ICAM-1, and VCAM-1 concentrations correlated positively with hypoxanthine concentrations during reperfusion, whereas the concentrations of ICAM-1 correlated negatively with xanthine concentrations. The results of the present study suggested that the concentrations of adhesion molecules in the renal vein during reperfusion correlated with purine metabolites, reflecting metabolic changes in renal tissue.

Heterotopic rat heart transplantation (Lewis to F344): early ICAM-1 expression after 8 hours of cold ischemia

BACKGROUND

Primary graft dysfunction is a still poorly understood complication after cardiac transplantation. Ischemia/reperfusion injury contributes to different disorders resulting in impaired graft function.

METHODS

In a heterotopic rat heart transplantation model we extended graft ischemic time up to 8 hours.

RESULTS

Using immunohistochemistry we detected an up to 4-fold increase in intracellular adhesion molecule-1 (ICAM-1) expression during 4 hours of reperfusion, independent of ischemic time (30-minute ischemia: 7.65 +/- 2.15 without reperfusion, 19.46 +/- 4.6 after 4-hour reperfusion; 240-minute ischemia: 5.6 +/- 1.99 and 22.3 +/- 3.77; 480-minute ischemia: 3.7 +/- 1.56 and 13.1 +/- 2.2). Eight-hour ischemic allografts had an increase in CD8-positive cells (1.37 +/- 0.5 and 2.3 +/- 0.77) and a significant increase in MHC II expression (11.48 +/- 2.1 and 18.27 +/- 1.34) during 4 hours of reperfusion.

CONCLUSIONS

We hypothesize that these findings reflect an early inflammatory reaction in the allograft possibly triggered by oxidative stress. During therapeutic interventions, both of these pathways must be considered.

[Cell energetic loading in experimental renal transplant with different periods of warm ischemia]

INTRODUCTION AND GOALS

Renal procurement after a period of heart st op demands a previous knowledge of ischemia-reperfusion injuries means. To study cell injury mechanisms an experimental study has been designed in pigs, with different rangres of warm ischemia (0-30-45 and 90 min). The main goal was to research on the basis of ischemic injury.

MATERIAL AND METHODS

Biochemical parameters (creatinine, urine output), energetic loading (ATP, ADP, AMP and global energetic loading) and pathological studies as long as survival analysis by 5th day were completed.

RESULTS

Animal survival and graft viability range from 100% at 5th day in control and 30 min warm ischemia groups to 60% in 90 min warm ischemia group. Creatinine levels rises at 1st, 3rd and 5th day, especially in those non-viable organs. ATP levels decrease after warm ischemia period, increases ADP and AMP levels after reperfusion in those viable organs.

CONCLUSIONS

Prolonged periods of warm ischemia do not result necessarily in non-viable kidneys. Viable organs recover nucleotide levels early. Study of energetic cell loading levels is a good way to get on better in the knowledge of injury mechanisms after ischemia-reperfusion.

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.

Mechanisms of action of antithymocyte globulin: T-cell depletion and beyond

The success of allogeneic stem cell transplantation and solid-organ transplantation owes much to improvements in the immunosuppressive regimens that prevent graft-versus-host disease (GVHD) or suppress allograft rejection. A better understanding of the immune mechanisms underlying induction of immunological tolerance is the key to successful transplantation. Polyclonal antibodies such as antithymocyte globulins (ATG) have been used for decades. The common belief is that ATG efficacy relies on its capacity to deplete T lymphocytes. The aim of this review is to offer an overview of the recent findings that have been demonstrated in ATG's immunomodulatory activity. The polyclonal nature of ATG is reflected in its diverse effects on the immune system: (1) T-cell depletion in blood and peripheral lymphoid tissues through complement-dependent lysis and T-cell activation and apoptosis; (2) modulation of key cell surface molecules that mediate leukocyte/endothelium interactions; (3) induction of apoptosis in B-cell lineages; (4) interference with dendritic cell functional properties; and (5) induction of regulatory T and natural killer T cells. As a consequence, ATG provides multifaceted immunomodulation paving the way for future applications and suggesting that the use of ATG should be included in the immunosuppression therapeutic armamentarium to help reduce the incidence of organ rejection and GVHD.

The aetiology and pathogenesis of chronic allograft nephropathy

Renal transplantation is the ultimate form of renal replacement therapy, and is the treatment of choice for many patients with end-stage renal failure. The advent of calcineurin inhibitor based immunosuppression resulted in the 1-year renal allograft failure rate dropping from around 50% twenty years ago to less than 10% in more recent times. Despite a massive improvement in renal allograft survival in the first year following transplantation 10-year graft survival can be as low as 50%. Chronic allograft nephropathy (CAN) is recognised as the main cause of renal allograft failure following the first year after transplantation. The diagnosis of CAN can only be made histologically. Typically biopsy specimens in grafts with CAN demonstrate an overall fibrotic appearance effecting the vascular endothelium, renal tubules, interstitium, and glomerulus. The risk factors for CAN are divided into alloimmune and alloimmune independent. Alloimmune dependent factors include acute cellular rejection, severity of rejection, subclinical rejection and HLA mismatch. Alloimmune independent factors such as delayed graft function, donor age, Cytomegalovirus infection, donor/recipient co-morbidity and of course calcineurin inhibitor toxicity are important in the development of CAN. The pathogenesis of CAN is complex, multifactorial, and unfortunately incompletely understood. There are a number of pivotal steps in the initiation and propagation of the fibrosis seen in biopsy specimens from kidneys with CAN. Endothelial activation in response to one or more of the aforementioned risk factors stimulates leukocyte activation and recruitment. Recruited leukocytes subsequently infiltrate through the endothelium and induce key effector cells to secrete excessive and abnormal extracellular matrix (ECM). Enhanced deposition of ECM is a histological hallmark of CAN. This paper aims to present a concise yet accurate and up-to-date review of the literature concerning the aetiological factors and pathological processes which are present in the generation of CAN.

Allogeneic activation is attenuated in a model of mouse lung perfused with magnesium-deficient blood

Hypomagnesemia, which is frequently observed in patients treated with calcineurin inhibitors to prevent rejection after allogeneic transplantation, has been associated with a faster rate of decline in allograft function. The effect of hypomagnesemia on lung allograft has not been reported yet. In our model of isolated mouse lung, we have evaluated the early effects of allogeneic lung perfusion with blood from magnesium (Mg)-deficient mice for 3 h on lung activation and remodelling, compared to isogeneic perfusion. Hypomagnesemia (0.21+/-0.07 mmol Mg(2+)/l) was observed in blood from Mg-deficient mice, but no inflammatory pattern. The mRNA level of the intercellular adhesion molecule (ICAM)-1, but neither of the vascular cell adhesion molecule (VCAM)-1, nor of the cytokines tumor necrosis factor (TNF)alpha and interleukin (IL)-2, was enhanced (p<0.05). Although caspase-3 mRNA was transiently enhanced, no apoptotic cells were evidenced in lung tissues even after 3 h. Using cDNA array, we found that the genes encoding RANKL, RANK, TNFR2, NFATX, IL-1R2, IL-6R gp130, SOCS3, PDGFRB, P63, CSF3R, CXCL1, CXCL5, CX3CL1, CSF1, which are involved in inflammation and apoptosis regulation, were markedly up-regulated in allogeneic conditions. Our results support a limited allogeneic activation and an early stage of the inflammatory process in lung, at the time of inflammatory cell recruitment without lung tissue remodelling, as a result of hypomagnesemia. These findings suggest that cyclosporine-related hypomagnesemia, observed in most of the transplanted patients, does not constitute an additional risk for lung allograft outcome.

Circulating adhesion molecules during kidney allograft reperfusion

Adhesion molecule expression is an important event during early transplant failure. The aim of the present study was to examine the release of adhesion molecules during the first minutes of kidney allograft reperfusion in relation to delayed graft function and acute graft rejection. We enrolled 49 renal transplant recipients, including 13 cases of delayed graft function (DGF) and 11 cases of acute graft rejection (AR). Plasma concentrations of E-selectin, VCAM-1 and ICAM-1 after 3 min of reperfusion were significantly higher than in the iliac vein before reperfusion. There was no statistically significant difference between patients with and without DGF as regards E-selectin, VCAM-1 and ICAM-1 concentrations in the iliac vein before and in the renal vein after 3 min of reperfusion. Concentrations of adhesion molecules in the iliac vein before reperfusion and in the renal vein after 3 min of reperfusion did not differ significantly between patients with and without AR except for ICAM-1 iliac vein concentration which was significantly increased in AR patients. Plasma levels of E-selectin, ICAM-1 and VCAM-1 were increased after kidney allograft reperfusion. Moreover, elevated serum levels of ICAM-1 before transplantation correlated with subsequent acute kidney allograft rejection. The results suggest that elevated ICAM-1 levels may be implicated in acute graft rejection.

Recombinant integrin CD11b A-domain blocks polymorphonuclear cells recruitment and protects against skeletal muscle inflammatory injury in the rat

The beta2 integrin CD11b/CD18 (CR3) is a major adhesion receptor of neutrophils, normally utilized to fend off infections. This receptor contributes, however, to multiple forms of non-infectious inflammatory injury when dysregulated as shown in gene knock-outs and through the use of blocking monoclonal antibodies. The major ligand recognition site of CR3 has been mapped to the A-domain in the CD11b subunit (CD11bA). The recombinant form of this domain exhibits a ligand binding profile similar to that of the holoreceptor. To assess the potential anti-inflammatory activity of CD11bA as a competitive antagonist of CR3 in vivo, we assessed its effects on a developed animal model of traumatic skeletal muscle injury in the rat. Recombinant soluble rat CD11bA-domain fused to glutathione-S-transferase (GST) was administered intravenously in a single dose at 1 mg/kg to nine groups of Wistar rats, five in each group, 30 min before inducing traumatic skeletal muscle injury. Control animals received either a function-blocking anti-CD11b/CD18 monoclonal antibody (1 mg/kg), non-functional mutant forms of the CD11bA (D140GS/AGA, T209/A, D242/A), recombinant GST or buffer alone. In control animals, the wounded muscle showed oedema, erythrocyte extravasation and myonecrosis both within and outside the immediate wounded area (5-10 mm zone) and influx of neutrophils was detected 30 min post-wound, followed by a second wave 3 hr later. Wild-type CD11bA- or anti-CD11b monoclonal antibody (mAb)-treated rats showed a comparable and significant decrease in the number of infiltrating PMN (78 + 4%, n = 70 and 86 +/- 2%, n = 50, respectively) and preservation of the muscular fibres outside the immediate zone of necrosis (75 + 4%, n = 70, 84 +/- 1%, n = 50, respectively), compared to controls. These data demonstrate that CD11bA can be an effective tissue-preserving agent in acute inflammatory muscular injury.

Deletion of DOCK2, a regulator of the actin cytoskeleton in lymphocytes, suppresses cardiac allograft rejection

Allograft rejection is induced by graft tissue infiltration of alloreactive T cells that are activated mainly in secondary lymphoid organs of the host. DOCK2 plays a critical role in lymphocyte homing and immunological synapse formation by regulating the actin cytoskeleton, yet its role in the in vivo immune response remains unknown. We show here that DOCK2 deficiency enables long-term survival of cardiac allografts across a complete mismatch of the major histocompatibility complex molecules. In DOCK2-deficient mice, alloreactivity and allocytotoxicity were suppressed significantly even after in vivo priming with alloantigens, which resulted in reduced intragraft expression of effector molecules, such as interferon-γ, granzyme B, and perforin. This is mediated, at least in part, by preventing potentially alloreactive T cells from recruiting into secondary lymphoid organs. In addition, we found that DOCK2 is critical for CD28-mediated Rac activation and is required for the full activation of alloreactive T cells. Although DOCK2-deficient, alloreactive T cells were activated in vitro in the presence of exogenous interleukin-2, these T cells, when transferred adoptively, failed to infiltrate into the allografts that were transplanted into RAG1-deficient mice. Thus, DOCK2 deficiency attenuates allograft rejection by simultaneously suppressing multiple and key processes. We propose that DOCK2 could be a novel molecular target for controlling transplant rejection.

Health disparities in transplantation: focus on the complexity and challenge of renal transplantation in African Americans

The field of renal transplantation has grown exponentially as a result of a greater understanding of the immune system and the advent of numerous immunosuppressive agents. Although African Americans and whites have benefited from these advances, equivalent long-term success eludes African Americans who are disadvantaged in gaining access to renal transplantation. This review summarizes the obstacles for African Americans to end-stage renal disease(ESRD) care, focusing on transplantation. Factors that predispose African Americans for ESRD, impede this ethnic group from timely transplantation, and negatively influence graft survival are examined. Possible solutions to these persistent problems are offered.

Sirolimus-mediated prolongation of rat cardiac allograft survival is enhanced by beta1 integrin very late antigen-4 blockade

The beta1 integrin very late antigen-4 (VLA-4) plays a key role in lymphocyte rolling and adhesion to endothelium, and in lymphocyte migration through fibronectin. Thus, VLA-4 blockade may modulate allograft rejection. Here, we examined the effect of WAY-279, a small molecule VLA-4 antagonist, combined with sirolimus in a model of vascularized heart allograft (BN --> LEW) in the rat. Recipients were treated with low doses of WAY-279 (10-50 mg/kg, bid) and/or sirolimus (0.04 mg/kg) for 14 days, starting on the day of transplantation. The median-effect principle and the combination index (CI) were used to assess the combined effect of WAY-279 and sirolimus (CI < 1: synergism; CI = 1: summation; CI > 1 antagonism). Low doses of WAY-279 or sirolimus alone slightly prolonged allograft survival as compared to control group (MST = 7 days). When recipients were treated with WAY-279 and sirolimus, the cardiac allograft survival was synergistically prolonged for up to 45 days (P < .001; CI = 0.174-0.970). We showed that a concomitant treatment of WAY-279 with sirolimus produced a synergistic effect in prolonging cardiac allograft survival in the rat.

Methoxyethyl-modified intercellular adhesion molecule-1 antisense phosphorothiateoligonucleotides inhibit allograft rejection, ischemic-reperfusion injury, and cyclosporine-induced nephrotoxicity

BACKGROUND

The addition of phosphorothioate (PS) groups to natural phosphodiester (PD) antisense oligodeoxynucleotides (oligo) prevents their in vivo hydrolysis by nucleases allowing an RNase-dependent elimination of targeted mRNA. To further improve oligo function 2'-methoxyethyl (ME) groups were attached to selected nucleotides at the 3'-end because ME groups block RNase activity.

METHODS/RESULTS

ME modification of PS- or PD/PS-oligo targeting human intracellular adhesion molecule (ICAM)-1 mRNA significantly increased the degree and duration of the in vitro inhibitory effects without compromising selectivity and specificity. A 7-day intravenous or oral therapy with rat ME/PS-modified ICAM-1 antisense oligo extended the survivals of kidney allografts. In addition, ME/PS-modified ICAM-1 antisense oligo reduced ischemic-reperfusion injury in kidneys, as measured by glomerular filtration rate, creatinine levels, and infiltration with leukocytes. Finally, a 14-day treatment with cyclosporine (CsA)-induced nephrotoxicity in syngeneic kidney transplants correlated with both increased ICAM-1 protein expression and infiltration with leukocytes. Graft perfusion and treatment of recipients with ICAM-1 antisense ME/PS-oligo alleviated the nephrotoxic effect and decreased ICAM-1 expression and leukocyte infiltration.

CONCLUSIONS

ME/PS-modified ICAM-1 antisense oligo is very effective in inhibiting the ICAM-1-dependent mechanism of graft infiltration and tissue damage involved in allograft rejection, ischemic-reperfusion injury, and CsA-induced nephrotoxicity.

Persistent cytomegalovirus infection is associated with increased expression of TGF- 1, PDGF-AA and ICAM-1 and arterial intimal thickening in kidney allografts

BACKGROUND

Cytomegalovirus (CMV) is a suggested risk factor for the development of chronic allograft nephropathy. Transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF) are important molecules in this process. We analysed the impact of persistent CMV infection in kidney allografts on the expression of growth factors, adhesion molecules and inflammation markers.

METHODS

In a population of 172 renal transplant recipients, CMV was diagnosed in 82 patients by pp65 antigenaemia test and viral cultures. Biopsies taken after CMV infection were available from 48 of the 82 patients for the demonstration of CMV antigens by immunohistochemistry and in situ DNA hybridization. Biopsy material for further analyses was available from 16 CMV patients. Five patients with no previous CMV infection were used as controls. Biopsy histology was scored according to Banff 97 classification.

RESULTS

In 11 out of 16 patients, persistent CMV antigens and/or DNA were demonstrated in the biopsy >2 months after the last positive finding in blood or urine. Increased expression of TGF-beta1 was recorded in tubuli and in arterial endothelium in biopsies with a positive CMV finding compared with controls. Also, the expression of PDGF-AA was increased in tubuli and somewhat in arterial endothelium in CMV-positive biopsies. The expression of intercellular adhesion molecule-1 (ICAM-1) was increased significantly in peritubular capillary endothelium. Vascular intimal thickening was increased in the biopsies with persistent CMV infection.

CONCLUSIONS

Persistent CMV infection in kidney allografts was associated with increased vascular changes and increased expression of TGF-beta1, PDGF-AA and ICAM-1.

Targeting leukocyte integrins in human diseases

As our understanding of integrins as multifunctional adhesion and signaling molecules has grown, so has their recognition as potential therapeutic targets in human diseases. Leukocyte integrins are of particular interest in this regard, as they are key molecules in immune-mediated and inflammatory processes and are thus critically involved in diverse clinical disorders, ranging from asthma to atherosclerosis. Antagonists that interfere with integrin-dependent leukocyte trafficking and/or post-trafficking events have shown efficacy in multiple preclinical models, but these have not always predicted success in subsequent clinical trials (e.g., ischemia-reperfusion disorders and transplantation). However, recent successes of integrin antagonists in psoriasis, inflammatory bowel disease, and multiple sclerosis demonstrate the tremendous potential of antiadhesion therapy directed at leukocyte integrins. This article will review the role of the leukocyte integrins in the inflammatory process, approaches to targeting leukocyte integrins and their ligands, and the results of completed clinical trials.

Cynaropicrin, a sesquiterpene lactone, as a new strong regulator of CD29 and CD98 functions

Cynaropicrin is a sesquiterpene lactone displaying immunomodulatory effects on the production of cytokine and nitric oxide from macrophages/monocytes. In this study we have examined inhibitory effect of cynaropicrin on activation of major adhesion molecules [CD29 (beta1 integrins), CD43, and CD98] on the cells assessed by U937 (promonocytic cells) homotypic aggregation. Cynaropicrin potently blocked CD29 (beta1 integrins)- and CD98-induced homotypic aggregation with IC(50) values of 3.46 and 2.98 microM, respectively, without displaying cytotoxicity. Similarly, flow cytometric analysis exhibited that cynaropicrin down-regulated strikingly surface level of CD29 and CD147, a functional regulator of CD98, but not CD43. More importantly, cynaropicrin inhibition was linked to blockade of extracellular signal-related kinase (ERK) activation and distinct from other enzyme inhibitors including rottlerin, propranolol, forskolin, and chloroquine, but not cytochalasin B. Therefore, our finding is the first demonstration that cynaropicrin may be a potent functional regulator of CD29 and CD98 via interrupting ERK activation which may be linked to cytoskeleton rearrangement, suggesting further application to CD29- and CD98-mediated diseases such as virus-induced chronic inflammation, and invasion, migration, and metastasis of leukocyte cancer cells.

Different faces of the heme-heme oxygenase system in inflammation

The heme-heme oxygenase system has recently been recognized to possess important regulatory properties. It is tightly involved in both physiological as well as pathophysiological processes, such as cytoprotection, apoptosis, and inflammation. Heme functions as a double-edged sword. In moderate quantities and bound to protein, it forms an essential element for various biological processes, but when unleashed in large amounts, it can become toxic by mediating oxidative stress and inflammation. The effect of this free heme on the vascular system is determined by extracellular factors, such as hemoglobin/heme-binding proteins, haptoglobin, albumin, and hemopexin, and intracellular factors, including heme oxygenases and ferritin. Heme oxygenase (HO) enzyme activity results in the degradation of heme and the production of iron, carbon monoxide, and biliverdin. All these heme-degradation products are potentially toxic, but may also provide strong cytoprotection, depending on the generated amounts and the microenvironment. Pre-induction of HO activity has been demonstrated to ameliorate inflammation and mediate potent resistance to oxidative injury. A better understanding of the complex heme-heme

Leukocyte infiltration and inflammatory antigen expression in cadaveric and living-donor livers before transplant

BACKGROUND

There is evidence to indicate that organs obtained from cadaveric donors may be injured as a result of inflammatory events occurring at around the time of brain death. The aim of this study was to investigate whether there are differences in the expression of proinflammatory molecules between cadaveric and living-donor livers before transplant and to determine whether there is any association with donor factors and posttransplant graft function.

METHODS

A comparison of biopsies obtained before implantation from cadaveric (n=22) and living-related donor (LRD) (n=10) livers was performed. Cryostat tissue sections were stained with antibodies to leukocyte subpopulations, adhesion molecules, and human leukocyte antigen class II antigens.

RESULTS

Significantly higher levels of CD3+ lymphocytes (1.5%+/-0.8% vs. 0.5%+/-0.3%; P=0.00004), CD68+ monocytes and macrophages (4.0%+/-1.2% vs. 2.7%+/-0.6%; P=0.0003), and Fas-ligand staining (4.2%+/-2.6% vs. 1.5%+/-1.1%; P=0.0003) were detected in cadaveric livers compared with LRD livers before transplantation. Furthermore, higher levels of intercellular adhesion molecule-1 expression were detected in cadaveric donor livers and found to be associated with longer periods of ventilation (P=0.01), infection in the donor (P=0.013), and administration of dopamine (P=0.03). Although there were no differences in neutrophil infiltration between cadaveric and LRD livers, significantly higher levels were found in cadaveric donors with infection (P=0.01).

CONCLUSION

This study demonstrates that inflammatory changes occur in cadaveric donor livers and are associated with events occurring during the period of intensive care. These proinflammatory changes did not seem to affect the short-term clinical outcome of cadaveric liver allografts but may contribute to alloimmune responses and impairment of graft function in the long term.

The role of selectins in inflammation and disease

Selectins are carbohydrate-binding molecules that bind to fucosylated and sialylated glycoprotein ligands, and are found on endothelial cells, leukocytes and platelets. They are involved in trafficking of cells of the innate immune system, T lymphocytes and platelets. An absence of selectins or selectin ligands has serious consequences in mice or humans, leading to recurrent bacterial infections and persistent disease. Selectins are involved in constitutive lymphocyte homing, and in chronic and acute inflammation processes, including post-ischemic inflammation in muscle, kidney and heart, skin inflammation, atherosclerosis, glomerulonephritis and lupus erythematosus. Selectin-neutralizing monoclonal antibodies, recombinant soluble P-selectin glycoprotein ligand 1 and small-molecule inhibitors of selectins have been tested in clinical trials on patients with multiple trauma, cardiac indications and pediatric asthma, respectively. Anti-selectin antibodies have also been successfully used in preclinical models to deliver imaging contrast agents and therapeutics to sites of inflammation. Further improvements in the efficiency, availability, specificity and pharmacokinetics of selectin inhibitors, and specialized application routes and schedules, hold promise for therapeutic indications.

Non-heart-beating versus cadaveric and living-donor livers: differences in inflammatory markers before transplantation

BACKGROUND

Liver transplantation from non-heart-beating donors (NHBD) has been reintroduced into clinical practice to increase the donor pool; however, little is known about the immune status of NHBD livers. The aim of this study was to assess intragraft cell populations and inflammatory markers in NHBD and to compare the findings with cadaveric and living-related donor (LRD) livers.

METHODS

Biopsy specimens were obtained from controlled NHBD (n=9), conventional cadaveric (n=22), and living-donor (n=10) livers at the end of cold storage. Cryostat sections were stained for monocytes-macrophages, T lymphocytes, and intercellular adhesion molecule (ICAM)-1.

RESULTS

The levels of leukocyte infiltration in NHBD reflected those found in conventional cadaver donors and were significantly higher than in LRD livers. Similar levels of CD68+ monocytes-macrophages were detected in cadaver (4.0+/-1.2%) and NHBD livers (4.6+/-1.2%) and were significantly greater than in the LRD livers (2.6+/-0.5%, P<0.01). Furthermore, the levels of T lymphocytes in NHBD (1.1+/-0.6%) and cadaver donors (1.5+/-0.8%) were similar, and were higher than in LRD (vs. 0.47+/-0.3%, P<0.05). Twelve of 22 (60%) cadaver livers had high levels of ICAM-1 expression (grade 3), compared with only 1 of 10 (10%) LRD livers (P=0.02). Four of nine (44%) controlled NHBD livers expressed high levels of ICAM-1.

CONCLUSIONS

The results demonstrate that livers obtained from controlled NHBD before transplantation are similar to conventional cadaver donors regarding the level of leukocyte infiltration. Nevertheless, lower levels of ICAM-1 were detected in NHBD, suggesting less exposure to inflammatory mediators than conventional cadaver donor livers.

Functional antibodies to leukocyte adhesion molecules in antithymocyte globulins

BACKGROUND

Polyclonal antithymocyte globulins (ATG) induce T-cell depletion and functional impairment of nondeleted lymphocytes. Interference of ATG with the main leukocyte surface molecules involved in cellular adhesion and leukocyte-endothelium interaction was investigated in the present study.

METHODS

In three rabbit ATG, the authors measured antibodies to integrins, beta2-integrin ligands, and chemokine receptors by flow cytometry; chemotactic responses; and down-modulation of cell surface expression on lymphocytes, monocytes, and neutrophils.

RESULTS

Antibodies to CD11a/CD18 (leukocyte function-associated antigen-1 [LFA-1]) present in ATG induced a dose-dependent down-modulation of cell surface expression of this beta2 integrin on lymphocytes, monocytes, and neutrophils. In contrast, anti-LFA-1 monoclonal antibodies did not induce LFA-1 modulation unless cross-linked by a second antibody. ATG also contained functional antibodies to the beta1 integrin CD49d/CD29 (VLA-4), the alpha4beta7 integrin, CD50, CD54, and CD102 but not to CD62L. ATG were shown to bind to CXCR4 and CCR7 on lymphocytes, CXCR4, and CCR5 on monocytes; to down-modulate cell surface expression of CCR7; and to decrease monocyte chemotactic response to CCL5 (RANTES) and lymphocyte chemotactic response to CCL19 (MIP-3beta).

CONCLUSION

These results show that ATG may interfere with leukocyte responses to chemotactic signals but mostly inhibit the expression of integrins required for firm cellular adhesion. The latter property of inhibition is not shared by monoclonal antibodies, and it may contribute to decreasing graft cellular infiltration during acute rejection and possibly after postischemic reperfusion.

Combined analysis of cytokine genotype polymorphism and the level of expression with allograft function in African-American renal transplant patients

Cytokine gene polymorphism and expression levels were evaluated in a group of African-American patients who had undergone renal transplantation. It was hypothesized that possession of specific cytokine alleles might be influential in predisposing the recipient to allograft rejection. Thus, we sought to establish a relationship between cytokine gene polymorphism, the levels of cytokine expression, and the outcome of allograft function. Cytokine genotypes and mRNA transcript levels of IL-2, TNF-alpha, TGF-beta1, IL-10, IL-6 and IFN-gamma were determined using peripheral blood cells. Genomic DNA samples from 77 transplant recipients and 77 controls were tested by a multiplex PCR with specific primers for the above cytokines. The frequency distributions of cytokines were analyzed in respect to the clinical characterization, including delayed graft function (DGF), rejection episodes (REs) and stable graft function (SGF). The mRNA transcript level was tested both at pre- and early post-transplantation (day 1 and day 4) with primers for coding regions of the above cytokines in a RT-PCR assay. The majority of recipients with successful graft function were matched with their donors for only three out of the six HLA alleles. We have shown that the TGF-beta1 T/C G/G high producer and IFN-gamma T/A intermediate producer genotypes were associated with allograft rejection, whereas low IFN-gamma producer and high IL-10 producer genotypes were significantly protective of the allograft. There was some correlation between the TGF-beta1 high producer genotype and DGF, but it was not statistically significant. Overall, 77% of those who experienced REs carried the TGF-beta1 T/C G/G, high producer genotype as compared with 52% who experienced DGF, 39% with SGF (P<0.01, RR=2.0), and 27.3% of controls (P<0.003, RR=2.6). The IFN-gamma T/A intermediate producer genotype was found in 69.2% of patients with REs as compared with 26.8% of patients with SGF (P<0.008, RR=2.85). The IL-10, ATA/ATA low producer genotype was found in 38.5% of recipients with REs and 14.6% of recipients without REs (P<0.04, RR=0.53). Expression levels of mRNA transcript were correlated with genotype data, except for the TGF-beta1 high producer genotype where there was no significant difference between the level of mRNA transcript at pre- and post-transplantation. Low DRbeta1 and high DPbeta1 expression by recipient peripheral blood mononuclear cells before transplantation was associated with more SGF, whereas high DRbeta1 and low DPbeta1 expression at pretransplantation was associated with more REs (DRbeta1, P<0.001 and DPbeta1, P<0.05, respectively). We concluded that, dual analysis of cytokine genotype and expression levels by peripheral cells may be an important clue to understanding the contribution of the recipient's immune response to an allograft pre- and post-transplantation. Identification of peripheral markers diagnostic of rejection could allow advance anticipation of clinical outcome, and might reduce the need for tissue biopsy.

Monoclonal antibody against beta7 integrins, but not beta7 deficiency, attenuates intestinal allograft rejection in mice

BACKGROUND

beta7 integrins mediate homing and retention of lymphocytes to the normal and inflamed small bowel in a tissue-selective fashion. In the present study, we investigated the expression of beta7 integrins after small bowel transplantation (SBT) and tested the effects of blocking beta7-mediated pathways by using monoclonal antibody (mAb) or knockout mice.

METHODS

Heterotopic SBT from BALB/c to C57BL/6 (B6) was used as a surgical model. Expression of beta7 integrins was measured on recipient lymphocytes (CD4 and CD8 ) in spleen, blood, and mesenteric lymph nodes (MLN) using flow cytometry. To analyze the effects of blocking beta7 integrins on graft survival, either beta7-deficient B6 or wild-type B6 mice that were treated with mAb against beta7 were studied.

RESULTS

After allogeneic SBT, there were markedly increased levels of alpha4beta7 recipient CD8 lymphocytes in MLN, blood, and spleen as early as 3 days postoperatively. In contrast, alpha4beta7 integrin levels in isograft recipients were similar to those of normal mice. Mean survival time of intestinal allografts was not affected by beta7 deficiency (7.3+/-1 days) compared with wild-type mice (7.5+/-0.8 days). However, mAb against beta7 integrins significantly prolonged graft survival (12.8+/-1 days) compared with treatment with control mAb (7.3+/-1 days, <0.001). Histologic changes of SBT rejection were significantly attenuated when mice were given mAb against beta7.

CONCLUSION

As indicated by the increased levels of alpha4beta7 CD8 lymphocytes, activation of this integrin contributes to the immune response in SBT rejection. Furthermore, blocking beta7 integrins with mAb provides a suitable target for immunosuppressive therapy. The discrepancy in survival data obtained by mAb and beta7 deficiency may be a result of the more rapid activation of compensatory mechanisms in the knockout mice.

Changes in intragraft gene expression secondary to ischemia reperfusion after cardiac transplantation

BACKGROUND

Ischemia-reperfusion (I/R) injury in transplanted tissue is associated with changes in intragraft cytokines, chemokines, and adhesion molecules. The aim of this study was to perform a comprehensive analysis of gene expression in cardiac grafts secondary to I/R using microarray technology.

METHODS

Heterotopic brown Norway rat cardiac isografts were removed on postoperative day (POD) 3, 5, and 7. RNA was extracted, hybridized on U34A-Affymetrix high-density gene expression arrays, and compared with nontransplanted hearts using the log-average ration (LAR) and Student test.

RESULTS

Of the approximately 8,799 transcripts tested on each chip, 557 were significantly increased by POD5, with fewer induced transcripts observed on POD3 (46) and POD7 (32). The most significantly induced transcripts included MHC class II molecules, interferon-gamma inducing factor, apolipoprotein E, and cathepsin S. In contrast, the highest number of down-regulated transcripts was seen on POD3 (746) with fewer transcripts down-regulated by POD5 (162) and POD7 (298). Down-regulated transcripts included those involved in cellular metabolism: monoamine oxidase-A, mitochondrial-A synthase complex, and cytochrome oxidase subunit. By POD7, oxidative stress inducible protein tyrosine phosphatase and vascular endothelial cell growth factor were significantly decreased in transplanted isografts. Reverse-transcriptase polymerase chain reaction (RT-PCR) data on 10 transcripts agreed with the microarray results.

CONCLUSIONS

Microarrays using LAR analyses generally agree with previous data regarding intragraft changes during I/R injury but provide a larger number of molecules for future study. Although the largest number of down-regulated genes was seen early, the I/R effect may be continuing in that many transcripts remain down-regulated 7 days after transplantation.

Molecular and immunohistochemical characterization of the onset and resolution of human renal allograft ischemia-reperfusion injury

BACKGROUND Following allotransplantation, renal ischemia-reperfusion (I/R) injury initiates a series of events that provokes counter-adaptive immunity. Though T cells clearly mediate allospecific immunity, the manner in which reperfusion events augment their activation has not been established. In addition, comprehensive analysis of I/R injury in humans has been limited. METHODS To evaluate the earliest events occurring following allograft reperfusion and gain insight into those factors linking reperfusion to alloimmunity, we examined human renal allografts 30 to 60 minutes postreperfusion (n=10) and compared them with allografts with normal function that had resolved their I/R injury insult (>1 month posttransplant, n=6) and to normal kidneys (living donor kidneys before procurement, n=8). Biopsies were processed both for immunohistochemical analysis as well as for transcript analysis by real-time quantitative polymerase chain reaction (RT-PCR). RESULTS Reperfusion injury was characterized by increased levels of gene transcripts known to be involved in cellular adhesion, chemotaxis, apoptosis, and monocyte recruitment and activation. T-cell-associated transcripts were generally absent. However, recovered allografts exhibited increased levels of T-cell and costimulation-related gene transcripts despite normal allograft function. Consistent with these findings, the immediate postreperfusion state was characterized histologically by tubular injury and monocyte infiltration, while the stable posttransplant state was notable for T-cell infiltration. CONCLUSIONS These data suggest that monocytes and transcripts related to their recruitment dominate the immediate postreperfusion state. This gives way to a T-cell dominant milieu even in grafts selected for their stable function and absence of rejection. These data have implications for understanding the fundamental link between I/R injury and alloimmunity.

A peptide mimic of selectin ligands abolishes in vivo inflammation but has no effect on the rat heart allograft survival1

Acute heart allograft rejection is characterized by leukocyte infiltration and myocyte damage, key elements in the histological grading of rejection. The induction of selectins and their ligands on the graft postcapillary venular endothelium increases leukocyte tethering to, rolling on, and extravasation through the endothelium into graft parenchyma. We have characterized peptide mimicking selectin ligands by screening phage peptide libraries using anti-Lewis A antibodies and E-selectin as target molecules. The effect of this selectin- binding peptide, IELLQAR, on the prevention of inflammation and tissue damage and on the prolongation of graft survival in inbred DA (RT1a) rat heart allografts transplanted to WF (RT1v) recipients was tested. Bovine serum albumin (0.1%, solvent), VTSIAQA (control peptide), or IELLQAR were either continuously infused into the peritoneum via osmotic mini pumps or injected twice daily IV. Treatment with bovine serum albumin and VTSIAQA did not alter the number of graft infiltrating leukocytes or the histological grade of acute rejection, all scored as grade 4. On the contrary, the selectin binding peptide, IELLQAR, dose-dependently reduced inflammation and at the highest dose (6.0 mg/kg per day) eliminated the majority of graft infiltrating leukocytes, reduced the histological grade from 4 to 1B, but had no effect on graft survival. These data indicate that the intensity of inflammation related to the allograft rejection does not correlate to the graft survival.

Plasma and urinary soluble adhesion molecule expression is increased during first documented acute pyelonephritis

BACKGROUND

The degree of inflammatory reaction and leucocyte trafficking during acute pyelonephritis has been related to the risk of developing renal parenchymal scarring. Adhesion molecules play a central role in leucocyte recruitment during inflammation.

AIMS

(1) To determine whether circulating and urinary concentrations of E-selectin and intercellular adhesion molecule 1 (ICAM-1) were abnormal during first documented acute pyelonephritis; (2) to investigate whether circulating or urinary concentrations were predictive for the development of abnormalities on DMSA imaging.

METHODS

Plasma and urine samples were collected from 40 children with a first episode of acute pyelonephritis within one week of infection (acute sample) and at six weeks (late sample). Control samples were collected from 21 healthy age matched controls and 18 age matched controls with febrile illness not secondary to urinary tract infection.

RESULTS

Plasma and urinary sE-selectin were higher in acute samples (median 176.3 ng/ml and 0.12 ng/mmol respectively) compared with late (97.8 ng/ml and 0.029 ng/mmol) and both control (65.6 ng/ml and 0 ng/mmol) and febrile control (urine 0 ng/mmol) samples. Plasma sICAM-1 was higher in acute samples (428 ng/ml) than controls (365.2 ng/ml), and acute sICAM-1 urine concentrations were higher than febrile control concentrations (3.2 v 0.7 ng/mmol). No correlations were detected between sE-selectin or sICAM-1 and acute or late DMSA scan changes.

CONCLUSION

Plasma and urinary sE-selectin and sICAM-1 are significantly increased during acute pyelonephritis, though no correlation exists between the presence of high plasma or urine concentrations and DMSA scan changes, both during acute infection and six weeks post-infection.

New intra-renal graft genes associated with tolerance or rejection

BACKGROUND

Recipient type mononuclear cells infiltrating kidney allografts have different phenotypes and functions according to the fate of the graft. We hypothesized that different genetic programs were involved in rejected or accepted tissues and thus, transcripts that correlated with the clinical status could be identified by a differential expression strategy. This strategy was applied to miniature swine class II matched, class I disparate kidney grafts, which are accepted in recipient animals treated for 12 days with Cyclosporin A (CsA).

METHODS

The mRNA differential display RT-PCR technique (DDRT-PCR) was used to detect clinical status-specific transcripts. cDNA templates for this analysis were derived from biopsies of accepted (CsA treated) and rejected (untreated) kidney grafts 8 days post-transplantation.

RESULTS

A first screening procedure identified 23 PCR products differentially amplified in either tolerant or rejector samples. Nucleotide sequence of these partial transcripts showed that 11 out of 23 (48%) sequences had unknown open reading frames while 12 had substantial homology to known sequences. To validate the approach, rejection-associated (RA) cDNA 1 (RA-1) was characterized further. The results indicated that RA-1 is the porcine equivalent of secreted protein acidic and rich in cysteine (SPARC). Expression studies demonstrated that upregulation of SPARC gene transcription preceded other indicators of kidney dysfunction and correlated with the extent of graft infiltration.

CONCLUSION

DDRT-PCR appears to be a powerful technique to identify genes differentially expressed in grafted tissues that correlate with tolerance or rejection. One of the gene transcripts identified through this method, SPARC, may be a reliable marker of tissue injury consequent to cellular infiltration and rejection.

Expression of intercellular adhesion molecule-1 in the cortex of preserved rat kidneys

BACKGROUND

Prolonged cold ischemia has been shown to be an important factor in the development of posttransplant renal dysfunction. The exact mechanisms have not been completely defined. The expression of intercellular adhesion molecule-1 (ICAM-1) (CD 54) in rat kidneys stored in University of Wisconsin (UW) solution was studied in an attempt to correlate ischemia time with immunogenicity of the graft.

METHODS

Kidneys from male Lewis rats were perfused with UW solution, removed, and bathed in UW solution at 4 degrees C for 4, 12, 24, and 48 h. For the evaluation of expression of ICAM-1, immunohistochemical staining, Western blotting, and semiquantitative reverse transcriptase-polymerase chain reaction (RT-PCR) were performed.

RESULTS

Immunohistochemical staining in normal, nonischemic kidneys revealed that glomerular capillaries expressed ICAM-1 but that tubular cells did not. The preserved kidneys were analyzed by immunohistochemistry, Western blotting, and semiquantitative RT-PCR and showed increased transcription and expression of ICAM-1 in the cortex of the kidney. Expression reached a maximum at 24 h and declined at 48 h. The ICAM-1 protein expression in the preserved kidney cortex relative to control kidneys was increased at 4 h (1.68 +/- 0.60-fold of control kidneys, P = 0.06), 12 h (2.38 +/- 0.90-fold, P = 0.02), 24 h (3.70 +/- 1.29-fold, P = 0.01), and 48 h (2.00 +/- 0.54-fold, P = 0.01). The messenger RNA expression (the ratio of ICAM-1 to glyceraldehyde-3-phosphate dehydrogenase) in preserved kidneys cortex relative to control kidneys was increased at 4 h (1.19 +/- 0.14-fold of control kidneys), 12 h (1.38 +/- 0.16-fold), 24 h (1.77 +/- 0.29-fold), and 48 h (1.19 +/- 0.12-fold) (P < 0.05 for all time points).

CONCLUSIONS

We conclude that cold preservation of rat kidneys in UW solution induces increasing levels of ICAM-1 cell surface expression and gene transcription. Further study is necessary to determine if this increase in adhesion molecule expression increases the immunogenicity of the allograft and contributes to the development of posttransplant renal dysfunction.

Effects of catecholamine application to brain-dead donors on graft survival in solid organ transplantation

BACKGROUND

In a recent single-center study, donor use of catecholamines was identified to reduce kidney allograft rejection. This study investigates the effects of donor employment of adrenergic agents on graft survival in a large data base, including liver and heart transplants.

METHODS

The study was based on the registry of the Eurotransplant International Foundation including 2415 kidney, 755 liver, and 720 heart transplants performed between January 1 and December 31, 1993. A total of 1742 donor record forms referring to the cadaveric donor activities in 1993 were systematically reviewed with regard to employment of adrenergic agents. Catecholamine use was simply coded dichotomously and divided into three strata according to zero, single, and combined application. Multivariate Cox regression including age, gender, cause of brain death, cold ischemia, HLA-mismatching, number of previous transplants, and urgency in liver transplants was applied for statistical analysis.

RESULTS

Donor employment of catecholamines was associated with increased 4-year graft survival after kidney transplantation (hazard ratio [HR], 0.85; 95% confidence interval [95% CI], 0.74-0.98). The benefit is conferred in a dose-dependent manner and compares in quantitative terms with prospective HLA matching on class I and class II antigens (HR, 0.90; 95% CI, 0.84-0.97). Use of norepinephrine was predictive of initial nonfunction after heart transplantation (HR, 1.66; 95% CI, 1.14-2.43), but did not compromise liver grafts (HR, 0.94; 95% CI, 0.67-1.32).

CONCLUSIONS

Optimizing the management of brain-dead organ donors, including the possibility of selective administration of adrenergic agents, may provide a major benefit on graft survival without adverse side effects for the recipients. Further investigation on best use of adrenergic drugs, optimum dosage, and duration is warranted.

The contribution of adhesion molecule expression in donor kidney biopsies to early allograft dysfunction

BACKGROUND

Renal allograft rejection is associated with the expression of adhesion molecules on vascular endothelial and tubular epithelial cells.

METHODS

To assess whether the number of cell adhesion molecules expressed in donor kidneys can predict early rejection or delayed graft function, kidney biopsies from 20 living and 53 cadaveric kidney donors were obtained before engraftment into the recipients and the expression of the cell adhesion molecules intercellular adhesion molecule 1 (ICAM-1), vascular cell adhesion molecule 1 (VCAM-1), and endothelial leukocyte adhesion molecule (E-selectin) were determined by immunohistochemistry.

RESULTS

All biopsies from living donors showed significantly lower expression of ICAM-1 and VCAM-1 compared to biopsies from cadaveric donors. There was no difference in the expression of adhesion molecules on tubular cells between transplants with primary function compared to allografts with early rejection in living donated kidneys (ICAM-1: 2+/-8 vs. 3+/-8%; VCAM-1: 9+/-7 vs. 1+/-1%), as well as in cadaveric kidneys (ICAM-1: 38+/-29 vs. 39+/-38%; VCAM-1: 55+/-27 vs. 48+/-29%). The expression of ICAM-1 molecules on tubular cells was determined to be a predictor for the occurrence of delayed graft function in cadaveric kidneys (ICAM-1: 65+/-24* vs. 38+/-29% delayed graft versus primary graft function). No delayed graft function occurred in recipients of living donated kidneys.

CONCLUSIONS

These data suggest that adhesion molecule expression in donor biopsies is not a predictor for early allograft rejection, but can be used as a marker for the development of postischemic acute renal allograft failure.