A phase I trial of immunosuppression with anti-ICAM-1 (CD54) mAb in renal allograft recipients

Intercellular adhesion molecule-1/leukocyte function associated antigen-1 blockade inhibits alloantigen specific human T cell effector functions without inducing anergy

BACKGROUND

Intercellular adhesion molecule (ICAM-1) is important in leukocyte adhesion-dependent events and some data suggest that ICAM-1 provides T cell costimulation. We anlayzed the role of the ICAM-1 and leukocyte function associated antigen-1 (LFA-1) interaction in human T cell alloreactivity in vitro.

METHODS

Allo-antigen-induced T cell proliferation and cytotoxic T lymphocyte lytic activity were assessed by mixed lymphocyte reaction assay and 51 Chromium release assay, respectively. Immunostaining and flow cytometry were used to assess the expression of receptors on activated T cells.

RESULTS

Alloantigen-induced T cell proliferation and cytotoxic T lymphocyte activity were markedly inhibited by antibodies to ICAM-1 and LFA-1. These antibodies had to be present at the time of initial T cell receptor/antigen engagement to inhibit proliferation. Neither IL-2 nor IL-4 were involved in the observed inhibition by antibodies. Inhibition was not associated with altered cell surface expression of receptors such as CD3, CD4, ICAM-1, LFA-1, CD25, and HLA-DR however, these antibodies did impede the ability of generation of functionally active T cells. Interestingly, these antibodies inhibited soluble, but not immobilized OKT3-induced proliferation of peripheral blood leukocytes. Antibody-mediated inhibition of proliferation failed to impair the ability of T cells to subsequently proliferate in response to stimulation by the original or third party alloantigen or mobilize [Ca++]i in response to CD3 or LFA-1 receptor ligation.

CONCLUSIONS

These data demonstrate that blockade of ICAM-1/LFA-1 binding at the time of allorecognition potently blocks initial T cell effector functions that could be due to lack of effective T cell/APC engagement.

Protection from toxicant-mediated renal injury in the rat with anti-CD54 antibody

BACKGROUND

The benefit of the potent chemotherapeutic agent cisplatin in treating neoplasms is limited by nephrotoxicity. We tested the hypothesis that CD54 [intercellular adhesion molecule-1 (ICAM-1)] is an important mediator in cisplatin-mediated renal failure.

METHODS

The effect of a monoclonal anti-CD54 antibody was evaluated in a rat model of cisplatin toxicity. Renal function, histopathology, renal myeloperoxidase activity, and mortality were determined in the anti-CD54 and placebo groups.

RESULTS

Renal CD54 mRNA expression was markedly increased by 24 hours after exposure to cisplatin in mice. An improvement in renal function, mortality, and histological abnormalities was evident in animals exposed to cisplatin and treated with anti-CD54 antibody (mAb). Seven days after the administration of cisplatin, the mean creatinine was 0.65+/-0.05 mg/dl in the rats that received anti-CD54 mAb and 4.76+/-1.42 in control animals (P<0.02). Mortality was lower in experimental animals (0 vs. 29% in control rats seven days following cisplatin, P<0.04). Histological evidence of cell injury was markedly attenuated (P<0.04) in the treated compared with the control rats.

CONCLUSION

CD54 may be critical in the pathophysiology of renal injury following cisplatin, perhaps by its effects on leukocyte-endothelial interactions.

Donor catecholamine use reduces acute allograft rejection and improves graft survival after cadaveric renal transplantation

BACKGROUND

Epidemiological data implicate that renal transplants from living unrelated donors result in superior survival rates as compared with cadaveric grafts, despite a higher degree of human lymphocyte antigen (HLA) mismatching. We undertook a center-based case control study to identify donor-specific determinants affecting early outcome in cadaveric transplantation.

METHODS

The study database consisted of 152 consecutive cadaveric renal transplants performed at our center between June 1989 and September 1998. Of these, 24 patients received a retransplant. Donor kidneys were allocated on the basis of prospective HLA matching according to the Eurotransplant rules of organ sharing. Immunosuppressive therapy consisted of a cyclosporine-based triple-drug regimen. In 67 recipients, at least one acute rejection episode occurred during the first month after transplantation. They were taken as cases, and the remaining 85 patients were the controls. Stepwise logistic regression was done on donor-specific explanatory variables obtained from standardized Eurotransplant Necrokidney reports. In a secondary evaluation, the impact on graft survival in long-term follow-up was further measured by applying a Cox regression model. The mean follow-up of all transplant recipients was 3.8 years (SD 2.7 years).

RESULTS

Donor age [odds ratio (OR) 1.05; 95% CI, 1.02 to 1.08], traumatic brain injury as cause of death (OR 2.75; 95% CI, 1.16 to 6. 52), and mismatch on HLA-DR (OR 3.0; 95% CI, 1.47 to 6.12) were associated with an increased risk of acute rejection, whereas donor use of dopamine (OR 0.22; 95% CI, 0.09 to 0.51) and/or noradrenaline (OR 0.24; 95% CI, 0.10 to 0.60) independently resulted in a significant beneficial effect. In the multivariate Cox regression analysis, both donor treatment with dopamine (HR 0.44; 95% CI, 0.22 to 0.84) and noradrenaline (HR 0.30; 95% CI, 0.10 to 0.87) remained a significant predictor of superior graft survival in long-term follow-up.

CONCLUSIONS

Our data strongly suggest that the use of catecholamines in postmortal organ donors during intensive care results in immunomodulating effects and improves graft survival in long-term follow-up. These findings may at least partially be explained by down-regulating effects of adrenergic substances on the expression of adhesion molecules (VCAM, E-selectin) in the vessel walls of the graft.

Different roles for LFA-1 and VLA-4 integrins in T-B-cell interactions in vivo

Adhesion molecules are critical in the cellular interactions involved in specific immune responses. They are used for homing, cell migration, cell-cell contact and, in some cases, for the delivery of costimulatory signals. Since the host-versus-graft (HVG) reaction represents a particular form of T-B-cell interaction, we have explored whether the inhibition of lymphocyte function-associated antigen-1/intracellular adhesion molecule-1 (LFA-1/ICAM-1) interactions and the signalling through very late activation antigen-4 (VLA-4) have any effect on the development of a lupus-like disease in BALB/c mice injected at birth with (BALB/cxC57BL/6)F1 spleen cells. In close association with the development of tolerance to donor allografts, these mice show a polyclonal activation of F1 donor B cells by alloreactive host CD4+ T cells, manifested by the production of autoantibodies (autoAbs) and the development of a mild glomerulonephritis. The dose of the monoclonal antibody (mAb) employed has been adjusted to block completely the molecule on the surface of peripheral lymphocytes without interfering with the induction of neonatal tolerance. Injection of saturating doses (100 microg/2 days) of either anti-LFA-1alpha or anti-ICAM-1 mAbs, but not anti-VLA-4alpha or anti-LFA-1beta mAbs, blocks the production of anti-ssDNA autoAbs and the thrombocytopenia characteristic of this HVG disease (HVGD). However, anti-VLA-4alpha treatment is only able to delay the production of autoAbs and the anti-LFA-1beta treatment, not to modify the evolution of the HVGD. These results point to the relevance of LFA-1/ICAM-1 interactions, but not of the VLA-4-mediated signal, in the polyclonal B-cell activation occurring during the allogeneic interactions between host T helper type 2 cells and donor B cells in HVGD.

ICAM-1 and CD11b inhibition worsen outcome in rats with E. coli pneumonia

We investigated whether inhibiting an endothelial adhesion molecule [intracellular adhesion molecule 1 (ICAM-1)] would alter outcome and lung injury in a similar fashion to inhibition of a leukocyte adhesion molecule (integrin CD11b) in a rat model of gram-negative pneumonia. Inhibition of ICAM-1 with monoclonal antibody (MAb) 1A29 (1 mg/kg sc or 0.2 or 2 mg/kg iv, q 12 h x 3) or of CD11b with MAb 1B6 (1 mg/kg sc, q 12 h x 3) were compared against similarly administered placebo proteins in rats challenged with intrabronchial Escherichia coli. After challenge, all animals were treated with antibiotics. ICAM-1 MAb (6 mg/kg, iv, total dose) increased mortality vs. control (P = 0.03). CD11b MAb (3 mg/kg, sc, total dose) did not significantly (P = 0.16) increase mortality rates, but this was not in a range of probability to exclude a harmful effect. All other doses of MAb had no significant effect on survival rates. ICAM-1 and CD11b MAbs had significantly different effects on the time course of lung injury, circulating white cells and lymphocytes, and lung lavage white cells and neutrophils (P = 0.04-0.003). CD11b MAb decreased, whereas ICAM-1 MAb increased these measures compared with control from 6 to 12 h after E. coli. However, from 144 to 168 h after E. coli both MAbs increased these measures compared with control rats but to a greater level with CD11b MAb. Thus both ICAM-1 and CD11b appear to be necessary for survival during E. coli pneumonia. Although these adhesion molecules may participate differently in early lung injury, with CD11b increasing and ICAM-1 decreasing inflammation and injury, both are important for the resolution of later injury. During gram-negative pneumonia the protective roles of ICAM-1 and CD11b may make their therapeutic inhibition difficult.

Hypothesis: is renal allograft rejection initiated by the response to injury sustained during the transplant process?

Allograft rejection can be caused by numerous factors such as damage to the donor kidney during surgical removal or implantation, injury sustained during the transport process between the donor and recipient, and suboptimal allograft perfusion during the intra- and post-operative period. In cadaveric allografts, damage can occur during cold storage, during the transit stage between donor and recipient, and hemodynamic instability due to the initial damage that caused its removal from the donor (such as brain death or trauma). We hypothesize that rejection requires recognition of this injury in addition to recognition of alloantigens. If indeed injury proves to be one factor in acute rejection episodes, then therapeutic efforts can be made to reduce injury during the transplantation process.

Mechanisms and consequences of phagocyte adhesion to endothelium

Leukocyte adhesion to endothelium is essential for the development of an appropriate immune-inflammatory response. The vital importance of leukocyte-endothelial adhesive interactions in host defense and homeostasis is illustrated by the clinical manifestations of patients with congenital defects of leukocyte adhesion functions. However, under some circumstances leukocyte adhesion to endothelium may instead lead to vascular and tissue damage. In recent years, there has been remarkable progress in the understanding of the molecular basis of leukocyte adhesion to endothelium, and this knowledge has led to a new approach to immunomodulation in human disease, ie 'antiadhesion' therapy. This review focuses on cell adhesion molecules mediating adhesion of circulating phagocytes to vascular endothelium, on congenital defects of phagocyte adhesion in man, and on the current status of antiadhesion therapy directed towards phagocyte and endothelial adhesion molecules. We will also consider markers of phagocyte activation, which may provide a means to identify those patients who would benefit most from antiadhesion therapy.

Neutrophil and endothelial cell interactions in sepsis. The role of adhesion molecules

Although adhesion molecules present on circulating neutrophils and endothelial cells are essential for normal host defense, generalized activation of these molecules has been implicated in the inflammatory tissue injury occurring during sepsis and septic shock. A review of both preclinical and clinical studies suggests, however, that although these molecules mediate tissue injury related to a variety of microbial and host inflammatory mediators, their predominant role during sepsis with infection is a protective one.

Adhesion molecule polymorphisms in chronic renal allograft failure

BACKGROUND

Chronic allograft failure (CAF) is a major cause of late graft loss in renal transplantation. Up-regulation of adhesion molecules has been demonstrated in renal allograft biopsies during both acute and chronic rejection, and these molecules are known to regulate leukocyte migration into the graft.

METHODS

A single-center retrospective study was performed between 1985 and 1996 on renal transplant recipients who developed CAF. Genotyping was performed for five polymorphisms in intercellular adhesion molecule-1 (ICAM-1), E-selectin, and L-selectin. Frequency data for the polymorphisms in the CAF group (N = 62) and their matched donors, where available (N = 33), were compared with a group of recipients with graft survival of more than 10 years (N = 110) and a group of United Kingdom (UK) controls (N = 101).

RESULTS

A variant allele in exon 4 of ICAM-1 (R241) was more common in the CAF recipients compared with both long-term survivors and UK controls (19.4 vs. 10.0 and 9.4%, P = 0.015 and 0.025). In addition, stratification by time to graft failure caused by CAF revealed more rapid failure in the presence of another ICAM-1 variant in the recipient (E469) in exon 6 (P = 0.033).

CONCLUSIONS

ICAM-1 polymorphisms may represent a predetermined genetic risk factor for CAF. The polymorphism in exon 4 is in the Mac-1 binding site, and that in exon 6 is in the fifth immunoglobulin-like domain. Potential mechanisms of action of ICAM-1 variants in CAF include an alteration of activity as an adhesion molecule, altered costimulation, or a minor histocompatibility antigen.

A randomized multicenter trial of the anti-ICAM-1 monoclonal antibody (enlimomab) for the prevention of acute rejection and delayed onset of graft function in cadaveric renal transplantation: a report of the European Anti-ICAM-1 Renal Transplant Study Group

BACKGROUND

T-cell activation through T-cell receptor engagement requires co-stimulatory molecules and also adhesion molecules such as ICAM-1. Moreover ICAM-1 mediates leukocyte invasion from the blood into tissue during inflammatory processes. In animal studies using mouse monoclonal antibodies against ICAM-1 (enlimomab), renal allograft survival has been improved and reperfusion damage from ischemia reduced. The European Anti-ICAM-1 Renal Transplant Study (EARTS) was a randomized, double-blind, parallel-group, placebo-controlled study lastingl year and performed in 10 transplant centers in Europe.

METHODS

A total of 262 recipients of cadaveric kidneys were given either enlimomab or a placebo for 6 days and were given triple immunosuppressive therapy of cyclosporine, azathioprine, and prednisolone. The primary efficacy endpoint was the incidence of the first acute rejection within 3 months, and each event was assessed by a committee including investigators and independent pathologists.

RESULTS

There was no significant difference in the incidences of first acute rejection at 3 months between the placebo and enlimomab groups (39% vs. 45%), and enlimomab did not reduce the risk of delayed onset of graft function (DGF) (26% vs. 31%). Neither was there a difference in patient survival (95% vs. 91%) or graft survival (89% vs. 84%) at 1 year. Fatal events occurred in 19 (7%) patients (7 placebo, 12 enlimomab). Clinically, the most important non-fatal adverse events were infections; however, there was no statistically significant difference between the incidences in the two groups (70% vs. 79%).

CONCLUSION

Short term enlimomab induction therapy after renal transplantation did not reduce the rate of acute rejection or DGF.

Anti-ICAM-1 Monoclonal Antibody R6.5 (Enlimomab) Promotes Activation of Neutrophils in Whole Blood

R6.5 (BIRR-1, Enlimomab), a murine IgG2a mAb to the human ICAM-1, inhibits leukocyte adhesion to the vascular endothelium, thereby decreasing leukocyte extravasation and inflammatory tissue injury. In initial clinical trials, R6.5 proved to be beneficial in reducing both disease activity in refractory rheumatoid arthritis and the incidence of acute rejection after kidney and liver allograft transplantations. However, adverse effects such as fever, leukopenia, or cutaneous reactions were not infrequent. We studied the effects of R6.5 on neutrophil function in whole blood samples ex vivo. Surprisingly, at the concentrations achieved in clinical trials, R6.5 activated neutrophilic granulocytes, as indicated by a significant increase in expression of the adhesion molecule β2-integrin CD11b, a concurrent decrease in L-selectin expression, and an enhancement of the oxidative burst activity. Neutrophil activation was not exerted by an anti-ICAM-1 mAb of the IgG1 isotype, by isotype-matched, irrelevant anti-2-phenyloxazolone mAb, or by F(ab′)2 fragments of R6.5. Neutrophil activation was completely inhibited by soluble complement receptor type 1. We conclude that in whole blood, R6.5 activates resting neutrophils in a complement-dependent manner. This finding can explain, at least in part, the side effects associated with R6.5 therapy.

Renal thrombotic microangiopathy associated with anticardiolipin antibodies in hepatitis C-positive renal allograft recipients

Hepatitis C virus (HCV) infection has been associated with de novo or recurrent membranoproliferative glomerulonephritis and acute transplant glomerulopathy in transplanted kidneys. Recently, anticardiolipin antibodies (ACA) have been linked with chronic HCV infection. A few reports have suggested an association between ACA and renal allograft thrombosis. This study examines the clinical and pathologic features of HCV-positive renal allograft recipients at our institution. From 1990 to 1996, 379 kidney transplants were performed. We identified 18 recipients (4.8%) with HCV-positive serology pretransplant. Determination of IgG and IgM ACA was performed by enzyme-linked immunosorbent assay, using pretransplant sera. Among the 18 patients, five patients presented with biopsy-proven de novo renal thrombotic microangiopathy (RTMA), occurring 5 to 120 d (median, 14 d) after transplant. No differences in pretransplant characteristics were observed between patients with (n = 5) or without (n = 13) RTMA. All five patients had a positive ACA test (either IgG or IgM titer > 2 SD above normal), compared with only one of 13 patients without RTMA. The mean value for IgG ACA was significantly higher in the RTMA patients than in patients without RTMA (22.9 +/- 14.1 versus 6.9 +/- 4.9 IgG phospholipid units, P = 0.02); however, there were no significant differences in IgM ACA titers. Rheumatoid factor and complement C4 levels were normal in pretransplant sera of patients with RTMA. Patients with RTMA had their cyclosporine withdrawn (four of five) or the dose was decreased (one of five), and one of five underwent plasmapheresis. Four of five patients died within 5 yr after transplant, compared with no deaths in the other 13 patients. Finally, as a control group, seven HCV-negative renal allograft recipients who presented with RTMA/hemolytic uremic syndrome during the same time period were found to have normal ACA values (IgG or IgM). RTMA associated with ACA in HCV-positive renal allograft recipients may represent a new clinical entity. The occurrence of this syndrome may have deleterious consequences for patient and graft survival.

Amelioration of graft versus host disease with anti-ICAM-1 therapy

We have previously demonstrated an increase in the adhesion molecule lymphocyte function-associated antigen-1 (LFA-1) in GVHD after small bowel transplantation (SBTx) and a therapeutic effect for the monoclonal antibody (MoAb) to LFA-1 in the same model. The present study evaluated the role of MoAb to LFA-1's ligand, intercellular adhesion molecule-1 (ICAM-1) in GVHD. Methods. GVHD was created in LBNF1 rats by heterotopic vascularized SBTx from Lewis donors. Saline treated SBTx-GVHD and sham-operated control animals were compared to animal groups treated with MoAb to ICAM-1 or MoAb to ICAM-1 and LFA-1. GVHD was evaluated by measuring spleen index, white blood cell count, bowel permeability, weight loss, and animal survival. RESULTS. Animals treated with the MoAb to ICAM-1 appeared clinically to have almost as severe GVHD as untreated animals; however, they had improved spleen indices, less neutropenia and weight loss, and survived longer than untreated animals (range 15-22 days in treated animals vs 12-16 days in untreated animals, P < 0. 01). Treatment with MoAb to both ICAM-1 and LFA-1 appeared to have a synergistic beneficial effect on GVHD (range 19-29 days, P < 0.001 vs untreated animals). Conclusion. MoAb to ICAM-1 alone or in combination with MoAb to LFA-1 ameliorates GHVD after SBTx and prolongs survival.

Antisense modulation of the ICAM-1 phenotype of a model human bone marrow stromal cell line

Efficient stable gene transfer was achieved in a model human bone marrow stromal cell line, KM-102, using both Epstein-Barr virus and BK virus episomal expression vectors. Using this episomal expression system, effective overexpression and inhibition of ICAM-1 expression was achieved in stably transfected KM-102 cells by sense and antisense RNA gene transfer, respectively. Loss of surface ICAM-1 on antisense KM-102 transfectants did not significantly affect adhesion to LFA-1-bearing JY hematopoietic cells. However, KM-102 ICAM-1 overexpressors demonstrated enhanced binding (2.5-fold) to phorbol ester-treated, but not untreated, LFA-1-bearing JY cells. The increased binding could be blocked with anti-ICAM-1 antibodies. These findings suggest that while ICAM-1 is not required for basal adhesion between stromal and hematopoietic cells, stromal ICAM-1 may contribute to stromal:leukemic cellular interaction when bound to the phorbol ester-dependent high-avidity state of hematopoietic LFA-1.

Protection against allograft rejection with intercellular adhesion molecule-1 antisense oligodeoxynucleotides

BACKGROUND

We designed an antisense phosphorothioate oligodeoxynucleotide (oligo) to specifically inhibit the expression of rat intercellular adhesion molecule-1 (ICAM-1) mRNA (IP-9125).

METHODS

IP-9125 oligo was delivered intravenously by osmotic pump alone or in combination with cyclosporine (CsA) to recipients in order to prevent the rejection of kidney or heart allografts. In additional experiments, kidney allografts were perfused with IP-9125 before grafting.

RESULTS

IP-9125 inhibited ICAM-1 mRNA and ICAM-1 protein expression in rat aortic endothelial cells; scrambled controls IP-12140 and IP-13944 were ineffective. Untreated ACI (RT1a) recipients rejected Lewis (RT1l) kidney allografts at a mean survival time of 8.5+/-1.1 days. A 14-day intravenous administration of 2.5 mg/kg/day IP-9125 prolonged the survival of kidney allografts to 39.2+/-16.4 days; 5.0 mg/kg/day, to 43.0+/-17.5 days; and 10.0 mg/kg/day, to 50.4+/-21.6 days. In contrast, a scrambled control IP-12140 was not effective. A combination of 10 mg/kg/day IP-9125 and 1.0 mg/kg/day CsA delivered for 14 days synergistically extended kidney allograft survival times 88.5+/-7.5 days. In contrast, the combination of 10.0 mg/kg/day control IP-12140 with CsA was ineffective (20.7+/-3.2 days) when compared with CsA alone (20.2+/-4.0 days). Similar results were obtained for heart transplants in recipients treated with IP-9125 alone or in combination with CsA. Furthermore, in situ immunostaining showed that IP-9125 significantly reduced the expression of ICAM-1 protein in kidney allografts. Finally, perfusion of kidney grafts alone with 20.0 mg per 2 ml of IP-9125 protected kidney allografts from rejection (37.5+/-7.5 days; P < 0.001), whereas perfusion with 20 mg per 2 ml of control IP-12140 was ineffective (12.6+/-5.0 days).

CONCLUSIONS

Rat ICAM-1 IP-9125 oligo inhibits ICAM-1 protein expression in vitro and in vivo as well as blocks allograft rejection when used for pretreatment of donors, graft perfusion, or postoperative treatment of recipients.

Alpha-melanocyte-stimulating hormone inhibits renal injury in the absence of neutrophils

BACKGROUND

We previously showed that alpha-melanocyte stimulating hormone (alpha-MSH) decreases ischemia/reperfusion injury even when started six hours after ischemia. Alpha-MSH inhibits both neutrophil accumulation and nitric oxide production. To determine the relative importance of alpha-MSH on the neutrophil pathway, we examined the effects of alpha-MSH in injury models where neutrophil effects are minimal or absent.

METHODS

We studied the effects of alpha-MSH in (1) intercellular adhesion molecule-1 (ICAM-1) knock-out and background mice that were subjected to 40 minutes of ischemia and 24 hours reperfusion, and (2) isolated kidneys that were subjected to in vivo ischemia for 20 minutes and then perfused ex vivo for one hour without neutrophils. To begin to search for direct tubule effects of alpha-MSH, we studied the effect of alpha-MSH on nitric oxide (NO) in endotoxin/interferon-gamma-treated mouse cortical tubule cells.

RESULTS

ICAM-1 knock-out mice had 75% less neutrophil infiltration than background mice after ischemia. Despite the relative lack of neutrophils, alpha-MSH inhibited renal injury in ICAM-1 knock-out mice. Alpha-MSH also significantly preserved GFR and tubular sodium reabsorption in the isolated perfused ischemic kidney model. Alpha-MSH and a nitric oxide inhibitor did not exhibit synergy. Finally, alpha-MSH inhibited nitrite production by 20% in the mouse cortical tubule cells (MCT), similar to parallel observations in a cultured mouse macrophage line (RAW cells).

CONCLUSIONS

We conclude that alpha-MSH decreases renal injury when neutrophil effects are minimal or absent, indicating that alpha-MSH inhibits neutrophil-independent pathways of renal injury. The preservation of sodium absorption ex vivo and inhibition of nitrite production in cultured MCT cells suggests that alpha-MSH inhibits tubular injury by direct tubular effects.

ICAM-1 antisense oligodesoxynucleotides prevent reperfusion injury and enhance immediate graft function in renal transplantation

BACKGROUND

Ischemia-reperfusion injury after organ transplantation is a major cause of delayed graft function. We showed earlier that antisense oligodesoxynucleotides (ODN) for intercellular adhesion molecule-1 (ICAM-1) ameliorate reperfusion injury after acute ischemia. This study tested the hypothesis that antisense ODN for ICAM-1 prevents ischemia-reperfusion injury and facilitates immediate graft function in a rat autotransplantation model.

METHODS

Both kidneys were removed from male Lewis rats and re-implanted the left kidney after 30 minutes of cold ischemia time. The warm ischemia time was 60 minutes. Sham operated, uninephrectomized animals served as controls for renal function and histology. ICAM-1 antisense ODN (5 mg/kg), reverse ODN, or saline-vehicle were administered to donor animals i.v. six hours before autotransplantation. Glomerular filtration rate (insulin clearance), and serum creatinine concentrations were measured 24 hours post-transplantation. Tubular necrosis severity was assessed by histological grading scale. ICAM-1 expression was determined by immunohistochemistry and Western blot.

RESULTS

Antisense ODN decreased ICAM-1 expression and leukocyte infiltration significant. Antisense ODN-treated animals showed significantly less tubular necrosis, than controls. Serum creatinine of antisense ODN-treated animals (N = 6) was 0.55 +/- 0.02 mg/dl compared to 1.92 +/- 0.07 mg/dl in reverse ODN-treated controls (N = 6; P < 0.01), 24 hours after transplantation. Antisense ODN-treated animals had normal GFR (0.93 +/- 0.07 ml/min/kidney wt) compared to sham-operated animals (0.95 +/- 0.09 ml/min/kidney wt), while autotransplanted animals treated with reverse ODN or saline-vehicle were all anuric. The ischemia-reperfusion-induced up-regulation of MHC class II was totally prevented by antisense ODN.

CONCLUSIONS

ICAM-1 inhibition ameliorates ischemia-reperfusion injury and prevents delayed graft function. Antisense ODN-treatment of donors or donor organs for ICAM-1 may be useful for the prevention of reperfusion injury in human renal transplantation.

Ischemia/reperfusion injury in human kidney transplantation: an immunohistochemical analysis of changes after reperfusion

Organs used for transplantation undergo varying degrees of cold ischemia and reperfusion injury after transplantation. In renal transplantation, prolonged cold ischemia is strongly associated with delayed graft function, an event that contributes to inferior graft survival. At present, the pathophysiological changes associated with ischemia/reperfusion injury in clinical renal transplantation are poorly understood. We have performed an immunohistochemical analysis of pre- and postreperfusion biopsies obtained from cadaver (n = 55) and living/related donor (LRD) (n = 11) renal allografts using antibodies to adhesion molecules and leukocyte markers to investigate the intragraft changes after cold preservation and reperfusion. Neutrophil infiltration and P-selectin expression were detected after reperfusion in 29 of 55 (53%) and 24 of 55 (44%) cadaver renal allografts, respectively. In marked contrast, neutrophil infiltration was not observed in LRD allografts, and only 1 of 11 (9%) had an increased level of P-selectin after reperfusion. Immunofluorescent double-staining demonstrated that P-selectin expression resulted from platelet deposition and not from endothelial activation. No statistically significant association was observed between neutrophil infiltration and P-selectin expression in the glomeruli or intertubular capillaries despite the large number of cadaver renal allografts with postreperfusion changes. Neutrophil infiltration into the glomeruli was significantly associated with long cold ischemia times and delayed graft function. Elevated serum creatinine levels at 3 and 6 months after transplantation were also associated with the presence of neutrophils and platelets after reperfusion. Our results suggest that graft function may be influenced by early inflammatory events after reperfusion, which can be targeted for future therapeutic intervention.

Cell adhesion molecules in clinical renal transplantation

Leukocyte adhesion molecules are critically involved at a number of stages in immune and inflammatory responses, and their importance in the response to a renal allograft has been recognized for some years. They are involved in antigen presentation, in the cascade of events leading to extravasation of leukocytes into the allograft, in the subsequent migration of leukocytes through the extracellular matrix, and in the interactions between effector and target cells. Thus the adhesion molecules are highly attractive targets for therapeutic intervention in organ transplantation. Strategies have been explored to exploit the involvement of adhesion molecules in ischemia/reperfusion injury, allograft rejection, and the induction of immunological tolerance. Furthermore, the expression of a number of adhesion molecules is regulated by cytokines, and elevated levels may be detected both in transplant biopsies and as soluble forms measured in serum and urine. It has been proposed that these changes in levels might provide useful information in the diagnosis of allograft rejection and differentiation from other causes of graft dysfunction.

Leucocyte adhesion molecules in ischaemic renal injury: kidney specific paradigms?

1. Renal ischaemic-reperfusion injury (IRI) is an important cause of acute renal failure in native kidneys and in allografts. 2. Leucocyte adhesion molecules CD11/CD18, intercellular adhesion molecule-1 and selectins mediate cardiac, skin and muscle IRI in experimental models and recent studies have begun to evaluate their role in renal IRI. 3. The CD11/CD18 has been shown to mediate renal IRI in rat models. 4. Intercellular adhesion molecule-1 has a more prominent role in mediating renal IRI than CD11/CD18 in both rat and mouse models. Blockade of both pathways together appears to provide synergistic protection. 5. Unlike in heart and muscle, L-selectin does not appear to mediate leucocyte recruitment to postischaemic kidney or tubular damage. 6. Leucocyte adhesion molecules may mediate renal IRI by mechanisms other than simply leucocyte migration, such as signal transduction and cell transport.

Reduction of inner ear inflammation by treatment with anti-ICAM-1 antibody

The in vivo effect of systemic administration of monoclonal antibody (mAb) against ICAM-1 (alphaICAM-1) in experimental immune-mediated labyrinthitis was evaluated. The alphaICAM-1-treated rats showed reduced inflammatory cell infiltration in the scala tympani and the perisaccular tissue of the endolymphatic sac. However, with this experimental paradigm, labyrinthitis could not be completely abolished. These findings suggest that ICAM-1-dependent pathways play an important role in the series of immunologic events occurring in the inner ear, and that the use of ICAM-1 antagonist may be a possible therapeutic approach to labyrinthitis.

Emerging therapies for acute renal failure

Ischemia is the most common cause of acute renal failure (ARF). In the last decade, several new and important pathophysiological mechanisms that underlie the renal dysfunction have been discovered. These pathophysiological mechanisms include the role of both calcium and calcium-dependent enzymes, oxidant stress, loss of polarity of the tubular cell, tubular obstruction and arginine-glycine-aspartic acid (RGD) peptides, neutrophils, intracellular adhesion molecules (ICAM), and growth factors. A better understanding of tubular and vascular mechanisms has led to therapeutic studies in animals and clinical trials in humans. In this review, the pathophysiology of ischemic ARF will be correlated with the rationale for both current and future therapies.

Anti-rejection prophylaxis by blocking selectin dependent cell adhesion after rat allogeneic and xenogeneic lung transplantation

OBJECTIVE

Adhesion molecules regulate the infiltration of leukocytes into the graft during rejection after lung transplantation. The first step of the adhesion cascade is mediated by selectins. Sialyl-LewisX is a ligand of P-selectin. The purpose of the study was to evaluate SLX, a synthetic oligosaccharide analog of Sialyl-LewisX, for anti-rejection prophylaxis after allogeneic and xenogeneic left lateral, orthotopic rat lung transplantation.

METHODS

In groups A and B, allogeneic lung transplantation was performed using fully incompatible rat strains (donors: Dark-Agouti (RT1a); recipients: Lewis (RT11)). In group A (n = 10), recipients recieved 200 microg/d SLX i.v. on day 0-4. Group B rats (n = 10) served as untreated controls. The animals were sacrificed on days 5 and 10, respectively. In groups C and D, xenogenic lung transplantation was performed using Gold Syrian hamsters as donors and Lewis rats as recipients. In group C (n = 10), recipients received 200 microg/d SLX i.v. on day 0-4. Group D rats (n = 10) served as untreated controls. The animals were sacrificed on days 2 and 5, respectively. Rejection was graded by histology from 0 (no rejection) to 5 (necrosis). By immunhistology, alveolar, interstitial CD11a, CD18 and VLA-4 positive leukocytes were counted.

RESULTS

Histologically, there were a lower grade of rejection (A: 2.7 +/- 0.6; B: 4.0 +/- 0.0; P < 0.05) and fewer CD11a positive leukocytes (A: 66 +/- 27; B: 186 +/- 73; P < 0.05) on day 5 in the SLX-treated allograft group compared to the untreated group. In xenotransplantation, SLX also reduced the grade of rejection (C: 3.3 +/- 0.5; D: 4.7 +/- 0.5; P < 0.05) and the number of CD11a positive leukocytes (C: 145 +/- 22; D: 176 +/- 20; P < 0.05) on day 2.

CONCLUSIONS

It is concluded, that the administration of SLX significantly reduces allograft rejection. After discontinuation treatment with SLX unmodified rejection appeared. SLX also modifies xenograft rejection, but to a lesser extent, and xenograft necrosis appeared during treatment in this model.

Prevention of transplant rejection: current treatment guidelines and future developments

In the past 2 decades, progressive improvements in the results of organ transplantation as a therapeutic strategy for patients with end-stage organ disease have been achieved due to greater insight into the immunobiology of graft rejection and better measures for surgical and medical management. It is now known that T cells play a central role in the specific immune response of acute allograft rejection. Strategies to prevent T cell activation or effector function are thus all potentially useful for immunosuppression. Standard immunosuppressive therapy in renal transplantation consists of baseline therapy to prevent rejection and short courses of high-dose corticosteroids or monoclonal or polyclonal antibodies as treatment of ongoing rejection episodes. Triple-drug therapy with the combination of cyclosporin, corticosteroids and azathioprine is now the most frequently used immunosuppressive drug regimen in cadaveric kidney recipients. The continuing search for more selective and specific agents has become, in the past decade, one of the priorities for transplant medicine. Some of these compounds are now entering routine clinical practice: among them are tacrolimus (which has a mechanism of action similar to that of cyclosporin), mycophenolate mofetil and mizoribine (which selectively inhibit the enzyme inosine monophosphate dehydrogenase, the rate-limiting enzyme for de novo purine synthesis during cell division), and sirolimus (rapamycin) [which acts on and inhibits kinase homologues required for cell-cycle progression in response to growth factors, like interleukin-2 (IL-2)]. Other new pharmacological strategies and innovative approaches to organ transplantation are also under development. Application of this technology will offer enormous potential not only for the investigation of mechanisms and mediators of graft rejection but also for therapeutic intervention.

Anti-ICAM-1 antibodies protect allografts against microvascular and parenchymal cell damage

Anti-ICAM-1 (anti-intercellular adhesion molecule-1) monoclonal antibodies (CD54) were tested for treating composite tissue allografts in the rat hindlimb-cremaster transplantation model for intravital microcirculatory studies. Twenty-four transplantations were carried out across major histocompatibility barriers between Lewis-Brown Norway and Lewis rats. Isograft control transplants were compared to nontreated allograft control transplants and to allografts treated with 1 mg/kg of anti-ICAM-1 monoclonal antibodies. At 24 and 72 hours, microcirculatory vessel diameters, red blood cell velocities, functional capillary perfusion, endothelial edema index, and leukocyte-endothelial interactions were measured. At 24 and 72 hours, the number of sticking leukocytes, sticking lymphocytes, transmigrating leukocytes, and the endothelial edema index in the treated allografts were significantly decreased more than in the other 2 groups (p < .05 for all variables). Anti-ICAM monoclonal antibodies significantly reduced leukocyte-endothelial interactions, protecting the allografts from acute microvascular and parenchymal injury.

The leukocyte cell adhesion cascade and its role in myocardial ischemia-reperfusion injury

Cell-cell and cell-matrix interactions are known to be mediated by specific cell adhesion receptors expressed on the cell surface. The characterization of these cell adhesion molecules has allowed researchers to examine their roles in a variety of physiologic and pathophysiologic conditions. Numerous studies have demonstrated that myocardial ischemia-reperfusion injury is an acute inflammatory process in which leukocytes are intimately involved. In this review, we summarize the current data on the leukocyte cell adhesion cascade, focus upon studies which have demonstrated specific cell adhesion molecule interactions which mediate the leukocyte involvement in myocardial ischemia-reperfusion injury and suggest future avenues of exploration and possible clinical implications of the studies reviewed.

The in vivo and in vitro characterisation of an engineered human antibody to E-selectin

BACKGROUND

E-selectin is an endothelial cell specific adhesion molecule that is believed to play an important role in the early stages of leukocyte extravasation.

OBJECTIVES

Here we describe the construction and evaluation of an engineered human monoclonal antibody that blocks E-selectin function.

RESULTS

SPLAT-1 is an engineered human monoclonal antibody that has a very similar affinity for E-selectin as its murine parent antibody. In vitro SPLAT-1 blocks the binding of human leukocytes to E-selectin and does not mediate antibody-dependent cellular cytotoxicity (ADCC) or complement-mediated lysis of endothelial cells. In vivo, SPLAT-1 inhibits the recruitment of leukocytes to cytokine-inflamed human skin grafted on to SCID mice and has a long circulating half-life in primates. It does not appear to provoke an immune response in primates even on repeat administration.

CONCLUSIONS

SPLAT-1 has the characteristics of a antibody suitable for human therapy studies.

Hypoxia induces intercellular adhesion molecule-1 on cultured human tubular cells

The adverse effects of acute renal ischemia are partly mediated through an infiltration of inflammatory cells into the tubulointerstitium. The expression of adhesion molecules such as intercellular adhesion molecule-1 (ICAM-1) by resident renal cells (endothelial cells and tubular cells) may facilitate this process. We investigated whether hypoxia stimulates the expression of ICAM-1 by cultured human proximal tubular cells (HPTC). Hypoxic culture conditions (PO2 < 4 kPa) stimulated the expression of ICAM-1 by HPTC in a time-dependent manner (P < 0.0001) as demonstrated by quantitative flow cytometry analysis. Quantitative PCR demonstrated an increase in ICAM-1 transcription. Re-oxygenation of tubular cells did not increase ICAM-1 expression further. TNF alpha concentration in culture supernatants increased with hypoxia, but blocking experiments demonstrated that TNF alpha was not implicated in hypoxia-induced expression of ICAM-1. Furthermore, the cytokines IL-6 and IL-1 beta were not involved, but the effect of hypoxia was blocked by PDTC, an antioxidant that may inhibit the activation of the transcription factor NF-kappa B. These data demonstrate that hypoxia is a stimulus that induces the synthesis and expression of the adhesion molecule ICAM-1, presumably via the activation of NF-kappa B.

Inhibition of homotypic adhesion of T-cells: secondary structure of an ICAM-1-derived cyclic peptide

The objective of this study was to elucidate the solution conformation of cyclo-(1,12) Pen1-Pro2-Ser3-Lys4-Val5-Ile6-Leu7-Pro8-Ar g9-Gly10-Gly11-Cys12 (1) derived from the intercellular adhesion molecule-1 (ICAM-1). Cyclic peptide 1 inhibits homotypic adhesion of T-cells (Molt-3) mediated by ICAM-1 and the leukocyte function-associated antigen-1 (LFA-1) on the surface of T-cells. Cyclic peptide 1 is more potent than is the linear peptide Pen1-Pro2-Ser3-Lys4-Val5-Ile6-Leu7-Pro8-Ar g9-Gly10-Gly11-Cys12 (2) in inhibiting homotypic adhesion. The difference in biological activity of peptides 1 and 2 may be due to the more stable conformation of cyclic peptide 1 compared to linear peptide 2 or because cyclization prevents the peptide from adopting non-productive conformation. Therefore, conformational studies of cyclic peptide 1 will give a better understanding of its biological active conformation. The conformational studies of cyclic peptide 1 were done by NMR, CD and molecular dynamics simulations. NMR studies indicated that the major conformation of cyclic peptide 1 contained trans-configuration at both X-Pro peptide bonds. Type I beta-turns at Lys4-Val5-Ile6-Leu7 and Leu7-Pro8-Arg9-Gly10 were found in cyclic peptide 1. The C- and N-terminal regions of this peptide were stabilized by antiparallel beta-sheet-like structure with the presence of intramolecular hydrogen bonds. The overall structure of this peptide exposed the hydrophobic side chains on one face of the molecule and the hydrophilic side chains on the other.

Effect of anti-intercellular adhesion molecule-1 and anti-leukocyte function associated antigen-1 monoclonal antibodies on rat-to-mouse cardiac xenograft rejection

BACKGROUND

The interaction between intercellular adhesion molecule-1 (ICAM-1) and its ligand, leukocyte function associated antigen-1 (LFA-1), is especially relevant in allograft rejection. We have previously shown that the simultaneous blockade of ICAM-1 and LFA-1 by monoclonal antibodies (mAbs) results in specific immunologic tolerance to cardiac allograft in a mouse model.

METHODS

We evaluated the roles of these adhesion molecules in xenograft rejection by using a rat-to-mouse concordant xenograft model to identify critical molecules for immunosuppression.

RESULTS

Lewis rat hearts transplanted into C3H/He mice were rejected within 5 to 7 days without treatment. A significant prolongation of xenograft survival (mean survival time, 11.6 days) was observed after treatment with anti-rat ICAM-1 and anti-mouse LFA-1 mAbs, when compared with nontreated mice or mice treated with different combinations of mAbs. Graft survival was prolonged in mice treated with FK506 (1 mg/kg/day), anti-rat ICAM-1, and anti-mouse LFA-1 mAbs (mean survival time, 22.2 days), whereas the same dose of FK506 alone was not effective. The mixed lymphocyte reaction showed that a combination of mAbs against mouse LFA-1-rat ICAM-1 and rat LFA-1-mouse ICAM-1 significantly inhibited the proliferation of mouse responders to rat stimulators and rat responders to mouse stimulators, respectively. Infiltration of mouse CD4 positive, mouse CD8 positive, and mouse LFA-1 positive cells, as well as dense deposition of mouse immunoglobulin G (IgG), IgM, and up-regulation of rat ICAM-1, on the graft endothelial cells were demonstrated by immunopathologic analysis of the rejected hearts. Flow cytometric analysis with rat spleen cells demonstrated the presence of xenoreactive antibodies (mouse IgG and IgM) in the recipient's serum. This xenoreactive antibody production was delayed but not inhibited by treatment of the recipients with anti-rat ICAM-1 and anti-mouse LFA-1.

CONCLUSIONS

Blockade of the donor side ICAM-1 and the recipient side LFA-1 is critical for immunosuppression with anti-ICAM-1-LFA-1 treatment. Humoral factors may be responsible for xenograft rejection that occurs even after inhibition of the cell-mediated immune response by anti-ICAM-1 and anti-LFA-1 mAbs.

Dimethylfumarate is an inhibitor of cytokine-induced E-selectin, VCAM-1, and ICAM-1 expression in human endothelial cells

Most studies on the antipsoriatic mode of action of dimethylfumarate focused on its antiproliferative effects in keratinocytes. Because inflammatory skin diseases are associated with an upregulation of endothelial cell adhesion molecules and because the presence of inflammatory cells in dermis and epidermis is considered an important feature in psoriasis, we tested the effect of DMF on cytokine-induced adhesion molecule expression in HUVEC, using in situ ELISA and Northern blotting. Dimethylfumarate inhibited ICAM-1, VCAM-1, and E-selectin expression and reduced adhesion of U937 cells to stimulated HUVEC. Monoethylfumarate and fumaric acid had no effect. Similar inhibitory effects for DMF on VCAM-1 expression were observed after stimulation of HUVEC with LPS, PMA, IL-4, and IL-1 alpha or in combinations with TNF alpha. These data are in agreement with previously reported effects of DMF on intracellular thiol levels and inhibition of NF-kappa B activation. The inhibitory effect on cytokine-induced endothelial adhesion molecule expression may represent another target of dimethylfumarate in psoriasis.

Role of cell adhesion molecules in inflammatory bowel diseases

Infiltration of leukocytes into the bowel wall is a landmark of the inflammatory bowel diseases (IBD) ulcerative colitis (UC) and Crohn's disease (CD). The leukocyte movement is dependent on physical contact (adhesion) between the leukocytes and activated endothelial cells and can be divided into capturing, rolling, leukocyte flattening, and extra-vasation. The molecules shown to form the basis of leukocyte-endothelial binding are referred to as cell adhesion molecules (CAMs). Several of these molecules have additional properties, including interaction between leukocytes and proteins in the extracellular matrix, collaen in basement membranes, and stromal cells in lymphoid tissue and bone marrow. Furthermore, studies have indicated that CAMs interfere with the tumor cell's ability to metastasize. This paper will focus on a description of those CAMs that are either known or believed to be involved in the pathogenesis of IBD. Investigations of the presence and functions of these CAMs in IBD is reviewed, and potential new treatments are discussed.

Selective inhibition of vascular cell adhesion molecule-1 expression by verapamil in human vascular endothelial cells

Up-regulated expression of adhesion molecules on vascular endothelial cells (ECs) is an initial event in leukocyte adhesion to ECs, which is a crucial step in the process of inflammatory or immune reaction leading to organ transplant rejection. Verapamil and other calcium channel blockers have been reported to improve transplantation outcome and seem to possess immunosuppressive functions. Therefore, we tested the effect of verapamil on adhesion molecule expression of ECs and adherence of leukocytes to ECs. Verapamil was added to replicate human umbilical vein EC cultures, before adding cytokines. Protein and mRNA expression of E-selectin, vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 were measured by cell-ELISA and by Northern blot analysis after stimulation of ECs. Adherence of leukocytes to ECs was analyzed after stimulation of ECs by tumor necrosis factor-alpha, with pretreatment of verapamil. Verapamil selectively inhibited cytokine-induced protein and mRNA levels of VCAM-1, and suppressed cell adherence between tumor necrosis factor-alpha-stimulated ECs and mononuclear leukocytes or Molt-4 cells. These results suggest that verapamil may suppress immune response partly via inhibition of VCAM-1 expression on ECs and a certain subset of lymphocytes adherent to ECs.

Interstitial nephritis

Interstitial nephritis is an inflammatory process within the renal interstitium, and was one of the first observations made in the description of renal histopathology. Many different conditions are associated with an interstitial nephritis, and as a clinical diagnosis the term has little use unless causation is defined. However, there has been recent interest in the possibility of a common mechanism causing irreversible renal damage and eventually renal failure in many different types of interstitial nephritis. Such damage could take place due to blood-borne inflammatory mediators, or could be due to renal tubular inflammation related to abnormal components of the glomerular filtrate in renal failure, such as proteins or lipids. If such research were to result in effective therapy for interstitial nephritis, the progression of many forms of renal disease to end stage renal failure could be ameliorated.