The effect of leflunomide analogue FK778 on development of chronic rat renal allograft rejection and transforming growth factor-BETA expression

BACKGROUND: Chronic allograft nephropathy (CAN) remains the primary reason for late allograft loss in kidney transplantation. Transforming growth factor beta (TGF-beta) is a major mitogen mediating mesenchymal cell proliferation and epithelial to mesenchymal cell transition in CAN. FK778, an analogue of an active metabolite of leflunomide, is a promising immunosuppressive drug that inhibits de novo pyrimidine biosynthesis. Herein we investigated the effect of FK778 on development of chronic rejection and TGF-beta expression in combination with calcineurin inhibitors cyclosporine (CsA) and tacrolimus (Tac). METHODS: Kidney transplantations were performed from DA to WF rats and syngeneic control transplantations between DA rats. Allografts were immunosupressed alone with CsA (1.5 mg/kg/d subcutaneously) or Tac (1.5 mg/kg/d orally) or with combinations of FK778 (10 mg/kg/d orally) and CsA or Tac. No immunosuppression was given to syngeneic grafts. Grafts were harvested 90 days after transplantation for histology and immunohistochemistry (TGF-beta, TGF-betaR1). The chronic changes in allografts were scored according to the Chronic Allograft Damage Index (CADI). RESULTS: No histological signs of chronic rejection were seen in syngeneic grafts. According to CADI, moderate chronic changes were seen in grafts treated only with CsA or Tac. In both groups the changes typically associated with CAN were significantly ameliorated with FK778. CsA-treated grafts showed intense posttransplant expression of TGF-beta and TGF-betaR1 after 90 days. In grafts treated with Tac monotherapy this expression was substantially lower. FK778 markedly reduced the expression of TGF-beta and TGF-betaR1 when combined with calcineurin inhibitors and lesser expression was demonstrated with the combination of FK778 and Tac. CONCLUSIONS: Our results demonstrated that FK778 is a potent immunosuppressive drug having synergistic effects with calcineurin inhibitors. When combined with CsA or Tac, it decreased posttransplant TGF-beta ligand and receptor expression. Our data also showed that FK778 prevented chronic changes typically associated with CAN. Taken together our results suggested that FK778 could be a promising therapy for CAN in clinical kidney transplantation.     

Expression of TGF-beta and fibrogenic genes in transplant recipients with tacrolimus and cyclosporine nephrotoxicity

BACKGROUND: Long-term treatment with cyclosporine (CsA) or tacrolimus (Tac) results in chronic nephrotoxicity. Transforming growth factor-beta (TGF-beta) and other pro-fibrogenic molecules have been known to contribute to this side effect. A comparison of intrarenal expression of TGF-beta and other fibrogenic genes in biopsies from patients with either CsA or Tac nephrotoxicity have not been documented. This study compared the expression of TGF-beta, collagen, fibronectin, metalloproteinases (MMP-2, -9), tissue inhibitors of metalloproteinases (TIMP-2) and osteopontin in renal biopsies obtained from renal transplant recipients treated with either CsA or Tac as primary immunosuppressive agents. METHODS: Using RT-PCR, intrarenal expression of TGF-beta, collagen, fibronectin, MMP-2, MMP-9 and TIMP-2 were studied in renal biopsies from patients with histological diagnosis of CsA or Tac nephrotoxicity and acute rejection. TGF-beta protein expression was studied by staining section of biopsies with anti-TGF-beta antibody. RESULTS: Intrarenal expression of TGF-beta, collagen, fibronectin, MMP-2, TIMP-2, and osteopontin were significantly increased in patients treated with Tac nephrotoxicity compared with CsA nephrotoxicity. The intrarenal mRNA expression of these genes was higher in patients diagnosed with Tac/CsA nephrotoxicity compared to acute rejection. CONCLUSIONS: This study compares the intrarenal expression of TGF-beta and profibrogenic genes in renal transplant recipients treated with Tac and CsA. The results show that patients diagnosed with Tac nephrotoxicity exhibit increased expression of profibrogenic genes compared to CsA nephrotoxicity.     

Exogenous alpha-1-acid glycoprotein protects against renal ischemia-reperfusion injury by inhibition of inflammation and apoptosis

BACKGROUND: Although ischemia-reperfusion (I/R) injury represents a major problem in posttransplant organ failure, effective treatment is not available. The acute phase protein alpha-1-acid glycoprotein (AGP) has been shown to be protective against experimental I/R injury. The effects of AGP are thought to be mediated by fucose groups expressed on the AGP protein inhibiting neutrophil infiltration. However, the precise mechanism of protection remains to be established. We therefore studied the effects of exogenous human AGP (hAGP) in a mouse model of ischemic acute renal failure. METHODS: Mice were subjected to renal I/R and treated with hAGP, fucose-depleted hAGP, or control treated. Also, transgenic mice over-expressing rat AGP or wild-type controls were subjected to renal I/R. RESULTS: Treatment was with hAGP as well as fucose-depleted hAGP protected mice against I/R-induced acute renal failure. Surprisingly, AGP-over-expressing mice were not protected against I/R injury. Both natural and fucose-depleted hAGP inhibited the activation of the complement system, as determined by renal C3 deposition and influx of neutrophils measured by immunohistochemistry and myeloperoxidase-enzyme-linked immunoadsorbent assay. Tubular epithelial cell structure (actin cytoskeleton) and cell-cell interaction (tight-junction architecture) were completely preserved in AGP-treated mice. Also, epithelial caspase activation and apoptotic DNA cleavage were prevented by AGP treatment. CONCLUSIONS: Both natural and fucose-depleted hAGP protect against renal I/R injury by preservation of tubular epithelial structure and inhibition of apoptosis and subsequent inflammation. Therefore, hAGP can be regarded as a potential new therapeutic intervention in the treatment of acute renal failure, as seen after transplantation of ischemically injured kidneys.     

Association of high pretransplant sIL-6R plasma levels with acute tubular necrosis in kidney graft recipients

BACKGROUND: Delayed graft function is primarily caused by acute tubular necrosis (ATN). We studied in renal transplant recipients with posttransplant graft biopsy whether an up-regulated immune system in the recipient immediately before transplantation affects the risk of developing ATN and might be relevant for the pathogenesis of ATN. METHODS: In a retrospective study, we analyzed pretransplant and early posttransplant soluble interleukin (sIL)-1RA, interleukin (IL)-2, sIL-2R, IL-3, IL-4, IL-6, sIL-6R, IL-10, tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta2, interferon (IFN)-gamma, and neopterin plasma levels in patients with ATN (n=26). Matched patients with acute rejection (AR) (n=26) or normal posttransplant biopsy (n=26) served as controls. RESULTS: Pretransplant sIL-6R was higher (P=0.0004) and pretransplant TGF-beta2 lower (P=0.002) in patients with ATN than in patients with normal biopsy. ROC curves showed that high pretransplant sIL-6R has a high sensitivity (77%) and high specificity (64%) for ATN (P=0.002). Posttransplant plasma sIL-6R continued to be higher in ATN patients than in patients with normal biopsy (P=0.001). Patients with acute rejection showed pre- and posttransplant sIL-6R and TGF-beta2 plasma levels similar to those of patients with normal biopsy (P=NS). CONCLUSION: High pretransplant sIL-6R plasma levels are associated with an increased risk of ATN and might contribute to the development of ATN early posttransplant. Our data suggest that preactivation of the recipient's immune system increases the risk of ATN.     

The effect of FK778 on acute rat renal allograft rejection and expression of platelet-derived growth factor and transforming growth factor-beta

BACKGROUND: Acute rejection is the single most important risk factor for the development of subsequent chronic allograft nephropathy (CAN). Both platelet-derived growth factor (PDGF) and transforming growth factor-beta (TGF-beta) are major mitogens mediating mesenchymal cell proliferation and epithelial to mesenchymal cell transition. Early posttransplant induction of these growth factors may start molecular mechanisms leading to CAN. A new promising immunosuppressive drug, FK778, is an analogue of the active metabolite of leflunamide, which inhibits de novo pyrimidine biosynthesis. Herein we investigated the effect of FK778 on acute rejection and on the expression of PDGF and TGF-beta both alone and in combination with cyclosporine (CsA) or tacrolimus (Tac). METHODS: Kidney transplantations were performed from Dark Agouti (DA) to Wistar-Furth (WF) rats with syngeneic controls between DA rats. No immunosuppression was given to syngeneic grafts. Allografts were immunosuppressed with FK778 alone or in combination with CsA or Tac. Grafts were harvested on day 5 for histology and immunohistochemistry (PDGF-A, -B, PDGFR-alpha, -beta, TGF-beta1, and TGF-betaR1). RESULTS: FK778 ameliorated the inflammatory response and reduced PDGF and TGF-beta expression in a dose-dependent manner. It also showed synergy with calcineurin inhibitors, an effect that was stronger with Tac than with CsA. CONCLUSIONS: Our results indicated that FK778 decreased PDGF and TGF-beta expression early in acute rejection, suggesting it to be a promising therapy for CAN.     

Effect of nephrotoxins on tubulointerstitial injury and NF-kappaB activation in Adriamycin nephropathy

In a previous study we found that an episode of acute subclinical nephrotoxicity with gentamicin (G) (but not that induced by another proximal tubular cell nephrotoxin: ferric nitrilotriacetate, FeNTA), paradoxically reduced the progression of renal function and injury in uninephrectomized rats with nephrotic glomerular disease due to Adriamycin nephropathy (AN). Here, we hypothesized that subclinical exposure to G reduces early renal cortical tubulointerstitial inflammation and NF-kappaB activation in AN. To test this hypothesis, male Wistar rats with established AN received either G (10, 40, or 80 mg/kg by daily s.c.i. for 3 days), FeNTA (1.25, 5, or 10 mg/kg by a single i.p.i.), or vehicle (n=8 per group), 13 to 15 days after disease induction. Although G and FeNTA caused acute tubular necrosis in a dose-dependant manner (day 17), only the highest doses (10 mg/kg and 80 mg/kg) produced an acute elevation in the serum creatinine. On day 33, chronic tubulointerstitial inflammation (tubular atrophy, interstitial ED-1+/CD8+ cell accumulation) and NF-kappaB activation were exacerbated only in the groups that caused functional nephrotoxicity. These data suggest that: 1) the protective effect of subclinical G nephrotoxicity in chronic AN does not involve early changes in interstitial inflammation or NF-kappaB activation; and 2) a single episode of G exposure must be accompanied by clinically apparent nephrotoxicity in order to accelerate progression in a nonuremic model of chronic glomerular disease.     

Increased urinary excretion of alpha1-microglobulin at 6 months after transplantation is associated with urinary excretion of transforming growth factor-beta1 and indicates poor long-term renal outcome

BACKGROUND: Albumin and alpha1-microglobulin (alpha1M) are absorbed by two specific receptors in tubular epithelial cells. Any cell injury will disturb the reabsorption of these proteins, The increased urinary excretions of albumin or alpha1M could thus serve as a marker of subclinical graft lesions and as an early indicator of chronic allograft dysfunction. METHODS: We measured 24-hour urinary excretions of albumin, alpha1M, and transforming growth factor (TGF)-beta1 at 6 months after transplantation in 79 renal-graft recipients and recorded the changes in 24-hour creatinine clearance an average 51 (range 14-72) posttransplant follow-up months. RESULTS: At 6 months from transplantation, 46 of 79 (58%) patients were normoalbuminuric, 25 (32%) microalbuminuric, and 8 (10%) macroalbuminuric. In normoalbuminuric patients, urinary alpha1M/creatinine ratio was 10 times, and TGF-beta1/creatinine ratio approximately 5 times, higher than in the healthy subjects but lower than in albuminuric patients. In all patients, urinary alpha1M correlated with urinary TGF-beta1 (r=0.508, P<0.001), with albumin (r=0.220, P<0.05), and with the annual changes in 24-hour creatinine clearance (r=-0.273, P<0.05). During follow-up, renal function deteriorated in 20 of 33 (60%) patients with alpha1M/creatinine ratio greater than 5 mg/mmol, but only in 1 of 46 (2%) patients whose ratio was less than 5 mg/mmol (P<0.01), giving the ratio 5 mg/mmol or greater a 95% sensitivity to detect patients with poor long-term outcome. CONCLUSIONS: We show proximal tubular injury, measured by increased urinary alpha1M, to be present even in normoalbuminuric patients and to be associated with increased excretion of TGF-beta1 and with the annual deterioration of glomerular filtration rate. These findings show increased alpha1M/creatinine ratio to be an early and sensitive indicator of poor long-term outcome in renal-transplant patients.     

Effect of Nephrotoxins on Tubulointerstitial Injury and NF-κB Activation in Adriamycin Nephropathy

In a previous study we found that an episode of acute subclinical nephrotoxicity with gentamicin (G) (but not that induced by another proximal tubular cell nephrotoxin: ferric nitrilotriacetate, FeNTA), paradoxically reduced the progression of renal function and injury in uninephrectomized rats with nephrotic glomerular disease due to Adriamycin nephropathy (AN). Here, we hypothesized that subclinical exposure to G reduces early renal cortical tubulointerstitial inflammation and NF-κB activation in AN. To test this hypothesis, male Wistar rats with established AN received either G (10, 40, or 80 mg/kg by daily s.c.i. for 3 days), FeNTA (1.25, 5, or 10 mg/kg by a single i.p.i.), or vehicle (n = 8 per group), 13 to 15 days after disease induction. Although G and FeNTA caused acute tubular necrosis in a dose-dependant manner (day 17), only the highest doses (10 mg/kg and 80 mg/kg) produced an acute elevation in the serum creatinine. On day 33, chronic tubulointerstitial inflammation (tubular atrophy, interstitial ED-1 + /CD8 + cell accumulation) and NF-κB activation were exacerbated only in the groups that caused functional nephrotoxicity. These data suggest that: 1) the protective effect of subclinical G nephrotoxicity in chronic AN does not involve early changes in interstitial inflammation or NF-κB activation; and 2) a single episode of G exposure must be accompanied by clinically apparent nephrotoxicity in order to accelerate progression in a nonuremic model of chronic glomerular disease.     

Inhibition of the chemokine receptor CXCR2 prevents kidney graft function deterioration due to ischemia/reperfusion

BACKGROUND: Ischemia/reperfusion (I/R) injury after organ transplantation is a major cause of delayed graft function. Following I/R, locally produced CXC chemokines attract and activate granulocytes, which in turn promote graft damage. METHODS: We examined the involvement of granulocyte recruitment via the CXCR2 pathway in a rat model of 4 hours cold ischemia followed by kidney transplantation. Serum creatinine and intragraft granulocyte infiltration were monitored in the early phase posttransplant. A CXCR2 inhibitor, repertaxin, was given to recipients before transplantation (at -24 hours or -8 hours or -2 hours), immediately before reperfusion and 2 hours later. RESULTS: An increase of granulocyte chemoattractant CINC-1/interleukin-8 (IL-8) mRNA expression after I/R both in syngeneic and allogeneic transplantation was associated with a marked infiltration of granulocytes in renal tissue. In syngeneic transplantation, Lewis rats given 15 mg/kg repertaxin 24 hours before surgery had granulocyte graft infiltration and serum creatinine levels significantly reduced in respect to vehicle-treated animals. Intermediate effects were observed with 5 mg/kg, whereas the dose of 30 mg/kg had toxic effects. We found that reducing the pretreatment time to 8 hours before surgery was still effective. Prevention of granulocyte infiltration and serum creatinine increase was also obtained in allogeneic transplantation, when Brown Norway recipients of Lewis kidneys were given 15 mg/kg repertaxin starting 8 hours before surgery. CONCLUSION: Repertaxin treatment of the recipient animal was effective in preventing granulocyte infiltration and renal function impairment both in syngeneic and in allogeneic settings. The possibility to modulate I/R injury in this rat model opens new perspectives for preventing posttransplant delayed graft function in humans.     

Effects of Systemic Immunosuppression on Islet Engraftment and Function Into a Subcutaneous Biocompatible Device

The aim of this study was to explore the effect of sirolimus (Sir) and tacrolimus (Tac) on islets implanted into a subcutaneous (SC), prevascularized device in syngeneic rats. Animals received a 40-day treatment with Tac and Sir (alone or in combination) starting either on day 0 or 40 days after islet transplantation. Controls received no treatment. A 40-day washout period was performed after immunosuppression (IS). Glycemia and intravenous glucose tolerance tests (IVGTT) were assessed at follow-up. In the control group, 75% of recipients achieved stable normoglycemia after islet transplantation, while none reversed diabetes with any IS regimen started on day 0. Graft dysfunction was irreversible after IS withdrawal. Glucose clearance (IVGTT) was significantly impaired among Tac-treated compared with control groups (P < .05 with IS; P < .01 after washout). Among animals with established grafts, islet dysfunction which occurred under IS treatment persisted after washout in animals treated with Tac and Sir plus Tac. When compared with controls, glucose clearance was significantly impaired in the Tac and Tac plus Sir groups before and after IS (P < .01, Tac; P < 0.01, Tac plus Sir). Sir and Tac showed profound deleterious effects on islet cell engraftment and function, which may hinder the success of implantation into biohybrid devices. Nondiabetogenic IS protocols must be developed for clinical application of islet transplantation into biohybrid devices.     

Inhibition of 20-HETE synthesis and action protects the kidney from ischemia/reperfusion injury

20-Hydroxyeicosatetraenoic acid (20-HETE) production is increased in ischemic kidney tissue and may contribute to ischemia/reperfusion (I/R) injury by mediating vasoconstriction and inflammation. To test this hypothesis, uninephrectomized male Lewis rats were exposed to warm ischemia following pretreatment with either an inhibitor of 20-HETE synthesis (HET0016), an antagonist (20-hydroxyeicosa-6(Z),15(Z)-dienoic acid), an agonist (20-hydroxyeicosa-5(Z),14(Z)-dienoic acid), or vehicle via the renal artery and the kidneys were examined 2 days after reperfusion. Pretreatment with either the inhibitor or the antagonist attenuated I/R-induced renal dysfunction as shown by improved creatinine clearance and decreased plasma urea levels, compared to controls. The inhibitor and antagonist also markedly reduced tubular lesion scores, inflammatory cell infiltration, and tubular epithelial cell apoptosis. Administering the antagonist accelerated the recovery of medullary perfusion, as well as renal medullary and cortical re-oxygenation, during the early reperfusion phase. In contrast, the agonist did not improve renal injury and reversed the beneficial effect of the inhibitor. Thus, 20-HETE generation and its action mediated kidney injury due to I/R. Whether or not these effects are clinically important will need to be tested in appropriate human studies.     

Conversion to rapamycin immunosuppression in renal transplant recipients: report of an initial experience

BACKGROUND: The aim of this study is to evaluate the effects of RAPA conversion in patients undergoing cyclosporine (CsA) or tacrolimus (Tac) toxicity. METHODS: Twenty renal transplant recipients were switched to fixed dose rapamycin (RAPA) (5 mg/day) 0 to 204 months posttransplant. Drug monitoring was not initially used to adjust doses. The indications for switch were chronic CsA or Tac nephrotoxicity (12), acute CsA or Tac toxicity (3), severe facial dysmorphism (2), posttransplant lymphoproliferative disorder (PTLD) in remission (2), and hepatotoxicity in 1. Follow-up is 7 to 24 months. RESULTS: In the 12 patients switched because of chronic nephrotoxicity there was a significant decrease in serum creatinine [233+/-34 to 210+/-56 micromol/liter (P<0.05) at 6 months]. Facial dysmorphism improved in two patients. No relapse of PTLD was observed. Five patients developed pneumonia (two Pneumocystis carinii pneumonia, one infectious mononucleosis with polyclonal PTLD lung infiltrate) and two had bronchiolitis obliterans. There were no deaths. RAPA was discontinued in four patients, because of pneumonia in two, PTLD in one, and oral aphtous ulcers in one. RAPA levels were high (>15 ng/ml) in 7 of 13 (54%) patients. CONCLUSIONS: RAPA conversion provides adequate immunosuppression to enable CsA withdrawal. However, when converting patients to RAPA drug levels should be monitored to avoid over-immunosuppression and adequate antiviral and Pneumocystis carinii pneumonia prophylaxis should be given.     

Noninvasive assessment of early kidney allograft dysfunction by blood oxygen level-dependent magnetic resonance imaging

BACKGROUND: Blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) is a noninvasive method to assess tissue oxygen bioavailability, using deoxyhemoglobin as an endogenous contrast agent. We hypothesized that BOLD-MRI could accurately discriminate different types of rejection early after kidney transplantation. METHODS: Twenty-three patients underwent imaging in the first four months posttransplant. Five had normal functioning transplants and 18 had biopsy-proven acute allograft dysfunction (acute tubular necrosis [ATN, n=5] and acute rejection [n=13] including borderline rejection: n=3; IA rejection: n=4; IIA rejection: n=6: C4d(+) rejection: n=9). RESULTS: Mean medullary R2* (MR2*) levels (a measure directly proportional to tissue deoxyhemoglobin levels) were significantly higher in normal functioning allografts (R2*=24.3/s+/-2.3) versus acute rejection (R2*=16.6/s+/-2.1) and ATN (R2*=20.9/s+/-1.8) (P<0.05). The lowest MR2* levels were observed in acute rejection episodes with vascular injury i.e. IIA and C4d (+). Similarly, the lowest medullary to cortical R2* ratios (MCR2*) were present in allografts with IIA (1.24+/-0.05) and C4d(+) rejection (1.26+/-0.06). ROC curve analyses suggested that MR2* and MCR2* values could accurately discriminate acute rejection in the early posttransplant period. CONCLUSIONS: BOLD-MRI demonstrated significant changes in medullary oxygen bioavailability in allografts with biopsy-proven ATN and acute rejection, suggesting that there may be a role for this noninvasive tool to evaluate kidney function early after transplantation.     

Calcineurin inhibitor nephrotoxicity: longitudinal assessment by protocol histology

BACKGROUND: The role and burden of cyclosporine (CsA) nephrotoxicity in long-term progressive kidney graft dysfunction is poorly documented. METHODS: The authors evaluated 888 prospective protocol kidney biopsy specimens from 99 patients taken regularly until 10 years after transplantation for evidence of CsA nephrotoxicity. RESULTS: The most sensitive histologic marker of CsA nephrotoxicity was arteriolar hyalinosis, predicted by CsA dose and functional CsA nephrotoxicity. Striped fibrosis was associated with early initiation of CsA and the need for posttransplant dialysis (both P < 0.05). The 10-year cumulative Kaplan-Meier prevalence of arteriolar hyalinosis, striped fibrosis, and tubular microcalcification was 100%, 88.0%, and 79.2% of kidneys, respectively. Beyond 1 year, 53.9% had two or more lesions of CsA nephrotoxicity. Structural CsA nephrotoxicity occurred in two phases, with different clinical and histologic characteristics. The acute phase occurred with a median onset 6 months after transplantation, was usually reversible, and was associated with functional CsA nephrotoxicity (P < 0.05), high CsA levels (P < 0.05), and mild arteriolar hyalinosis (P < 0.001). The chronic phase of CsA nephrotoxicity persisted over several biopsies, occurred at a median onset of 3 years, and was associated with lower CsA doses and trough levels (both P < 0.05). It was largely irreversible and accompanied by severe arteriolar hyalinosis and progressive glomerulosclerosis (both P < 0.001). A threshold CsA dose of 5 mg/kg/day predicted worsening of arteriolar hyalinosis on sequential histology. CONCLUSIONS: Pathologic changes of CsA nephrotoxicity were virtually universal by 10 years and exacerbated chronic allograft nephropathy. CsA is unsuitable as a universal, long-term immunosuppressive agent for kidney transplantation. Strategies to ameliorate or avoid nephrotoxicity are thus urgently needed.     

The reaction of posttransplant denervated liver on the hemorrhagic shock in rats

OBJECTIVE: The aims of the study were to determine the effects of denervation on the function of the liver transplantation as a blood reservoir and to define its vulnerability to ischemic-reperfusion (I/R) injury after hemorrhagic shock. MATERIALS AND METHODS: Hemorrhagic shock with a mean arterial blood pressure (MAP) of 40 to 50 mm Hg was induced by withdrawing blood at a rate of approximately 1 mL/min among 10 posttransplant denervated rats and 10 sham rats for 1 hour. The rats were then resuscitated by retransfusing the drawn blood with sacrifice under deep anesthesia at 1 hour after resuscitation. The total amount of blood required to achieve hemorrhagic shock was compared between groups as well as the vulnerability and reactions of the posttransplant denervated liver to I/R injury after hemorrhagic shock as assessed by gene expressions of c-jun, c-fos, tumor necrosis factor (TNF)-alpha, interleukin (IL)6, IL-10, and heat-shock protein 70 (HSP70). RESULTS: The volume of blood that had to be drawn to reach a MAP of 40 to 50 mm Hg was not significantly different between the groups. One hour of hemorrhagic shock followed by resuscitation resulted in significant increases in the genes expression of c-fos, TNF-alpha, IL-6, IL-10, and HSP70 in comparison to the control values, but no difference was observed between experimental and sham groups. CONCLUSION: We suggest that the function of the liver as a blood reservoir and the gene expressions of c-fos and pro- and anti-inflammatory cytokines, as well as the protective protein HSP70 in response to I/R injury, were not altered by liver transplantation.     

ICAM-1 expression and leukocyte accumulation in inner stripe of outer medulla in early phase of ischemic compared to HgCl2-induced ARF

BACKGROUND: After ischemia/reperfusion (I/R), as well as after toxic insults, there is significant infiltration of leukocytes in the kidney. It is well known that antibodies against adhesion molecules [e.g., intercellular adhesion molecule-1 (ICAM-1)] protect the kidney against acute ischemic injury. In contrast, same antibody treatment did not protect the rat kidney against toxic acute renal failure (ARF) induced by HgCl2. Protection obtained by anti-adhesion treatment in I/R injury is an early phenomenon, since delaying the administration of anti-ICAM-1 for 8 hours did not protect the kidney anymore. The aim of this study was to compare the early ICAM-1 expression and leukocyte accumulation in different zones of ischemic and toxic injury. METHODS: Male Lewis rats were injected with HgCl2 (2 mg/kg, subcutaneously) or uninephrectomized Lewis rats were submitted to 30 degrees C warm ischemia (I/R injury). Rats were sacrificed at 2, 6, 12 and 24 hours. ICAM-1 (1A29) expression in kidney was evaluated morphometrically. Different subsets of leukocytes were stained by immunohistochemistry and counted in cortex, the outer stripe of the outer medulla (OSOM) and the level of the inner stripe of the outer medulla (ISOM). RESULTS: Although the functional and morphologic damage was comparable between the I/R and toxic ARF group, different ICAM-1 expression could be observed early after injury. ICAM-1 expression in the ISOM started already 2 hours after the onset of I/R injury, and was increased after 12 hours in the cortex and after 24 hours in the OSOM. In contrast, during the first 24 hours after injury, ICAM-1 expression in HgCl2-injured kidneys was not different from noninjured kidneys in the ISOM and the cortex, whereas in the OSOM, ICAM-1 expression increased. The number of polymononuclear cells (PMNs) was low in noninjured kidneys and did not increase in time after both I/R injury and after HgCl2-induced ARF. In the ISOM, significant monocyte and T-cell accumulation was observed early after I/R but not after HgCl2. There was no significant T-cell accumulation in the cortex or in the OSOM. CONCLUSION: After HgCl2, almost no leukocyte accumulation and up-regulation of ICAM-1 was observed the first 12 hours after injury. In contrast, very early after I/R injury, increased expression of ICAM-1 goes along with monocyte and T-cell accumulation in the ISOM, endorsing this particular zone as critical in renal I/R injury. These observations contribute to the understanding why anti-ICAM-1 treatment in acute I/R injury is successful, but fails in acute toxic injury induced by HgCl2.