Circulating FH Protects Kidneys From Tubular Injury During Systemic Hemolysis

Intravascular hemolysis of any cause can induce acute kidney injury (AKI). Hemolysis-derived product heme activates the innate immune complement system and contributes to renal damage. Therefore, we explored the role of the master complement regulator Factor H (FH) in the kidney's resistance to hemolysis-mediated AKI. Acute systemic hemolysis was induced in mice lacking liver expression of FH (hepatoFH-/-, ~20% residual FH) and in WT controls, by phenylhydrazine injection. The impaired complement regulation in hepatoFH-/- mice resulted in a delayed but aggravated phenotype of hemolysis-related kidney injuries. Plasma urea as well as markers for tubular (NGAL, Kim-1) and vascular aggression peaked at day 1 in WT mice and normalized at day 2, while they increased more in hepatoFH-/- compared to the WT and still persisted at day 4. These were accompanied by exacerbated tubular dilatation and the appearance of tubular casts in the kidneys of hemolytic hepatoFH-/- mice. Complement activation in hemolytic mice occurred in the circulation and C3b/iC3b was deposited in glomeruli in both strains. Both genotypes presented with positive staining of FH in the glomeruli, but hepatoFH-/- mice had reduced staining in the tubular compartment. Despite the clear phenotype of tubular injury, no complement activation was detected in the tubulointerstitium of the phenylhydrazin-injected mice irrespective of the genotype. Nevertheless, phenylhydrazin triggered overexpression of C5aR1 in tubules, predominantly in hepatoFH-/- mice. Moreover, C5b-9 was deposited only in the glomeruli of the hemolytic hepatoFH-/- mice. Therefore, we hypothesize that C5a, generated in the glomeruli, could be filtered into the tubulointerstitium to activate C5aR1 expressed by tubular cells injured by hemolysis-derived products and will aggravate the tissue injury. Plasma-derived FH is critical for the tubular protection, since pre-treatment of the hemolytic hepatoFH-/- mice with purified FH attenuated the tubular injury. Worsening of acute tubular necrosis in the hepatoFH-/- mice was trigger-dependent, as it was also observed in LPS-induced septic AKI model but not in chemotherapy-induced AKI upon cisplatin injection. In conclusion, plasma FH plays a key role in protecting the kidneys, especially the tubules, against hemolysis-mediated injury. Thus, FH-based molecules might be explored as promising therapeutic agents in a context of AKI.

Circulating miR-21, miR-210 and miR-146a as potential biomarkers to differentiate acute tubular necrosis from hepatorenal syndrome in patients with liver cirrhosis: a pilot study

BACKGROUND

Acute kidney injury (AKI) in cirrhotic patients may be functional (hepatorenal syndrome [HRS]) or structural (acute tubular necrosis [ATN]). The differentiation between these two conditions remains challenging; no definite biomarker with a clear cutoff value had been declared. miRNAs seem to be attractive innovative biomarkers to identify the nature of kidney injury in cirrhotic patients. This study aimed to investigate the possibility of using miR-21, miR-210 and miR-146a as differentiating markers between HRS and ATN.

METHODS

This pilot case control study included 50 patients with liver cirrhosis; 25 with HRS and another 25 with ATN beside 30 healthy controls. Real-time qPCR was used to measure the circulating miRNA tested.

RESULTS

Higher levels of miR-21 were observed in both ATN and HRS vs. controls with statistically significant difference between ATN and HRS. The means were 9.466±3.21 in ATN, 2.670±1.387 in HRS and 1.090±0.586 in controls. miR-146a and miR-210 were both significantly lower in ATN and HRS compared to controls with statistically significant differences between ATN and HRS. The means of miR-210 were 1.020±0.643, 1.640±0.605 and 3.0±0.532 in ATN, HRS and controls, respectively. The means of miR-146a were 2.543±1.929, 4.98±1.353 and 6.553±0.426 in ATN, HRS and controls, respectively. ROC analyses proved that the three studied mi-RNAs can be used as differentiating biomarkers between ATN and HRS with the best performance observed with mi-21 achieving specificity and sensitivity equal 96%.

CONCLUSIONS

miR-21, miR-210 and miR-146a may be candidate differentiating markers between HRS and ATN in cirrhotic patients.

Sulforaphane pretreatment prevents systemic inflammation and renal injury in response to cardiopulmonary bypass

OBJECTIVES

Systemic inflammatory responses are a major cause of morbidity and mortality in patients undergoing cardiac surgery with cardiopulmonary bypass. However, the underlying molecular mechanisms for systemic inflammation in response to cardiopulmonary bypass are poorly understood.

METHODS

A porcine model was established to study the signaling pathways that promote systemic inflammation in response to cardiac surgery with cardiopulmonary bypass under well-controlled experimental conditions. The influence of sulforaphane, an anti-inflammatory compound derived from green vegetables, on inflammation and injury in response to cardiopulmonary bypass was also studied. Intracellular staining and flow cytometry were performed to measure phosphorylation of p38 mitogen-activated protein kinase and the transcription factor nuclear factor-κB in granulocytes and mononuclear cells.

RESULTS

Surgery with cardiopulmonary bypass for 1 to 2 hours enhanced phosphorylation of p38 (2.5-fold) and nuclear factor-κB (1.6-fold) in circulating mononuclear cells. Cardiopulmonary bypass also modified granulocytes by activating nuclear factor-κB (1.6-fold), whereas p38 was not altered. Histologic analyses revealed that cardiopulmonary bypass promoted acute tubular necrosis. Pretreatment of animals with sulforaphane reduced p38 (90% reduction) and nuclear factor-κB (50% reduction) phosphorylation in leukocytes and protected kidneys from injury.

CONCLUSIONS

Systemic inflammatory responses after cardiopulmonary bypass were associated with activation of p38 and nuclear factor-κB pathways in circulating leukocytes. Inflammatory responses to cardiopulmonary bypass can be reduced by sulforaphane, which reduced leukocyte activation and protected against renal injury.

Preconditioning with triiodothyronine improves the clinical signs and acute tubular necrosis induced by ischemia/reperfusion in rats

Background

Renal ischemia/reperfusion (I/R) injury is manifested by acute renal failure (ARF) and acute tubular necrosis (ATN). The aim of this study was to evaluate the effectiveness of preconditioning with 3, 3, 5 triiodothyronine (T₃) to prevent I/R renal injury.

Methodology/Principal Findings

The rats were divided into four groups: sham-operated, placebo-treated (SO-P), sham-operated T_3- treated (SO- T₃), I/R-injured placebo-treated (IR-P), and I/R-injured T₃-treated (IR- T₃) groups. At 24 h before ischemia, the animals received a single dose of T₃ (100 μg/kg). Renal function and plasma, urinary, and tissue variables were studied at 4, 24, and 48 h of reperfusion, including biochemical, oxidative stress, and inflammation variables, PARP-1 immunohistochemical expression, and ATN morphology. In comparison to the SO groups, the IR-P groups had higher plasma urea and creatinine levels and greater proteinuria (at all reperfusion times) and also showed: increased oxidative stress-related plasma, urinary, and tissue variables; higher plasma levels of IL6 (proinflammatory cytokine); increased glomerular and tubular nuclear PARP-1 expression; and a greater degree of ATN. The IR-T₃ group showed a marked reduction in all of these variables, especially at 48 h of reperfusion. No significant differences were observed between SO-P and SO-T₃ groups.

Conclusions

This study demonstrates that preconditioning rats with a single dose of T₃ improves the clinical signs and ATN of renal I/R injury. These beneficial effects are accompanied by reductions in oxidative stress, inflammation, and renal PARP-1 expression, indicating that this sequence of factors plays an important role in the ATN induced by I/R injury.

Probenecid prevents acute tubular necrosis in a mouse model of aristolochic acid nephropathy

Experimental aristolochic acid nephropathy is characterized by early tubulointerstitial injury followed by fibrosis, reproducing chronic lesions seen in humans. In vitro, probenecid inhibits aristolochic acid entry through organic anion transporters, reduces specific aristolochic acid-DNA adduct formation, and preserves cellular viability. To test this in vivo, we used a mouse model of aristolochic acid nephropathy displaying severe tubulointerstitial injuries consisting of proximal tubular epithelial cell necrosis associated to transient acute kidney injury followed by mononuclear cell infiltration, tubular atrophy, and interstitial fibrosis. Treatment with probenecid prevented increased plasma creatinine and tubulointerstitial injuries, and reduced both the extent and the severity of ultrastructural lesions induced by aristolochic acid, such as the loss of brush border, mitochondrial edema, and the disappearance of mitochondrial crests. Further, the number of proliferating cell nuclear antigen-positive cells and total aristolochic acid-DNA adducts were significantly reduced in mice receiving aristolochic acid plus probenecid compared with mice treated with aristolochic acid alone. Thus, we establish the nephroprotective effect of probenecid, an inhibitor of organic acid transporters, in vivo toward acute proximal tubular epithelial cell toxicity in a mouse model of aristolochic acid nephropathy.

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.

Nitric Oxide in Gentamicin-induced Acute Tubular Necrosis in Rats

Gentamicin is still widely used in clinical practice in spite of its renal toxicity. The role of nitric oxide (NO) in that process is not completely elucidated. The aim of this study was to investigate the relationship between plasma level of NO and the histopathological changes of kidney in acute tubular necrosis (ATN) induced by gentamicin in rats. Study was carried out in Albino-Wistar rats, both sexes (n=16), average body weight 200-250 g. divided in two equal groups: control and gentamicin group. The control group was injected with 0.9% NaCl i.p. and gentamicin group was injected with gentamicin in the dose of 80 mg/kg/day i.p. in a period of 5 consecutive days. NO plasma level was determined by the production of nitrates and nitrites using classical colorimetrical Griess reaction. Kidney specimens were stained with hematoxylin-eosin (H-E) and Periodic acid-Schiff (PAS) stain. Semiquantitative histological analysis was used for the evaluation of the level of kidney damage. Both, the plasma NO level and the level of kidney damage were statistically higher in rats with gentamicin-induced ATN in comparison to the control group. In spite of that the correlation between plasma NO level and the level of kidney damage was not found. The rise of plasma level NO in gentamicin induced ATN in rats could possibly indicate on the role of NO in renal damage caused by gentamicin.

Protective role of caffeic acid phenethyl ester (cape) on gentamicin-induced acute renal toxicity in rats

The toxicity of gentamicin (GEN) in the kidney seems to relate to the generation of reactive oxygen species (ROS). Caffeic acid phenethyl ester (CAPE) has been demonstrated to have antioxidant, free radical scavenger and anti-inflammatory effects. It has been proposed that antioxidant maintain the concentration of reduced glutathione (GSH) may restore the cellular defense mechanisms and block lipid peroxidation thus protect against the toxicity of wide variety of nephrotoxic chemicals. We investigated the effects of CAPE on GEN-induced changes in renal malondialdehyde (MDA), a lipid peroxidation product, nitric oxide (NO) generation, superoxide dismutase (SOD), catalase (CAT) activities, GSH content, blood urea nitrogen (BUN) and serum creatinine (Cr) levels. Morphological changes in the kidney were also examined. A total of 32 rats were equally divided into four groups which were: (1) control, (2) injected with intraperitoneally (i.p.) GEN, (3) injected with i.p. GEN+CAPE and (4) injected with i.p. CAPE. GEN administration to control rats increased renal MDA and NO generation but decreased SOD and CAT activities, and GSH content. CAPE administration with GEN injections caused significantly decreased MDA, NO generation and increased SOD, CAT activities and GSH content when compared with GEN alone. Serum level of BUN and Cr significantly increased as a result of nephrotoxicity. CAPE also, significantly decreased serum BUN and Cr levels. Morphological changes in the kidney due to GEN, including tubular necrosis, were evaluated qualitatively. In addition, CAPE reduced the degree of kidney tissue damage induced by GEN. Both biochemical findings and histopathological evidence showed that administration of CAPE reduced the GEN-induced kidney damage. Our results indicated that CAPE acts in the kidney as a potent scavenger of free radicals to prevent the toxic effects of GEN both at the biochemical and histological level. Thus, CAPE could be effectively combined with GEN treatment.

Ichthyotoxic ARF after fish gallbladder ingestion: a large case series from Vietnam

Fish gallbladders are consumed in rural areas of Asia as a traditional medicine to improve symptoms of arthritis, decreased visual acuity, and impotence. Consumption of large amounts of this traditional medicine can result in systemic toxicities; in particular, acute renal failure. We reviewed records of all admissions to Cho Ray Hospital (Ho Chi Minh City, Vietnam) between January 1995 and December 2000 after this ingestion. Clinical courses and outcomes were similar in 16 of 17 patients. Within hours, patients experienced profuse vomiting (n = 16) and diarrhea (n = 15). All developed acute renal failure, with a mean serum creatinine concentration of 14.7 +/- 3.9 mg/dL (1,299.5 +/- 344.8 micromol/L). Four patients administered intravenous fluid (IVF) developed extracellular fluid volume overload, as did 1 patient not administered IVF. Time to peak creatinine concentration was 8.6 +/- 3.0 days, which was accompanied by decreased urine volume (174.7 +/- 161.6 mL/24 h). Blood pressure remained normal, with a mean arterial pressure of 91 +/- 12 mm Hg. Twelve patients required renal replacement therapy. A mean of 1.9 +/- 1.1 hemodialysis sessions was performed per patient. Sixteen patients recovered renal function; 1 patient died of fulminant hepatic failure. Kidney biopsies showed features of acute tubular injury. Acute renal failure after fish gallbladder ingestion is characterized by a failure to respond to IVF, an 8.6-day interval to peak creatinine level, frequent need for dialysis therapy, and findings on renal biopsy consistent with acute tubular necrosis. Acute renal failure after fish gallbladder ingestion has an excellent prognosis. However, death from fulminant hepatic failure can occur.

Amelioration with vessel dilator of acute tubular necrosis and renal failure established for 2 days

Seventeen Sprague-Dawley rats had ischemic nonoliguric acute renal failure (ARF) induced by vascular clamping resulting in their preischemic blood urea nitrogen (BUN) and creatinine levels of 16 +/- 1 and 0.56 +/- 0.05 mg/dl to increase to 162 +/- 4 and 8.17 +/- 0.5 mg/dl, P < 0.001, respectively, at day 4 of postischemia. Vessel dilator, a 37-amino-acid cardiac peptide hormone (0.3 microg x kg(-1) x min(-1) ip), decreased the BUN and creatinine levels to 53 +/- 17 mg/dl and 0.98 +/- 0.12 mg/dl (P < 0.001) in another seven animals where ARF had been established for 2 days. Water excretion doubled with ARF and was further augmented by vessel dilator. Transthoracic echocardiography revealed left ventricular dilation as a probable cause of the increase in vessel dilator in the circulation with ARF, and vessel dilator infusion reversed this dilation. At day 6 of ARF, mortality decreased to 14% with vessel dilator from 88% without vessel dilator. Acute tubular necrosis was <5% in the vessel dilator-treated rats compared with 25% to >75% in the placebo-treated ARF animals. We conclude that vessel dilator improves acute tubular necrosis and renal function in established ARF.

Acute renal failure due to oxalate ingestion

A 47-year-old man presented with acute renal failure following oxalate ingestion. Nausea and hematoemesis appeared four hours after attempted suicide and acute oliguric renal failure ensued the following day. The patient underwent four sessions of hemodialysis and then reverted to normal state. Histopathologic examination of renal biopsy specimen revealed the degeneration of the renal tubular epithelial cells associated with intracellular calcium oxalate crystal deposition. Most of the renal tubules were patent despite the intraluminar crystal deposition. These findings suggest that dysfunction of the renal tubular epithelial cell plays a more important role than tubular obstruction in developing acute renal failure.

Increase urinary hepatocyte growth factor excretion in human acute renal failure

Studies in animals suggest that hepatocyte growth factor (HGF) is an important mediator of kidney development, compensatory growth and tubule repair following acute injury, however, evidence for HGF action in human renal disease is scant. To determine whether increased renal production of HGF occurs in man, urine HGF excretion rate was measured in normals and in patients with a variety of acute and chronic renal diseases. Urine samples were collected from 9 healthy individuals, 25 individuals with acute tubular necrosis (ATN), 20 individuals with chronic glomerular disease, 9 patients with polycystic kidney disease and 10 individuals with severe chronic renal failure not yet receiving renal replacement therapy. Samples were initially frozen and then HGF content measured by ELISA and factored for creatinine concentration measured by autoanalyzer. Detectable but low levels of HGF were found in the urine of normals and in patients with chronic glomerular or polycystic disease. Levels were also not increased in patients with advanced, chronic renal insufficiency. In contrast, a marked increase in urine HGF was observed in patients with acute renal failure. In addition, HGF excretion tended to correlate with disease severity as higher levels were observed in patients with oliguric ATN. Urine HGF levels declined to control values in patients recovering from ATN, generally within one week. These findings are consistent with a role for HGF in promoting tubule cell proliferation, differentiation and recovery from acute tubular injury in man.

[Tubular necrosis after non-steroidal anti-inflammatory agents and acute alcoholic intoxication]

Acute nephrotoxicity due to nonsteroidal anti-inflammatory drugs is usually observed in clinical situations in which renal perfusion is compromised as in volume contraction. We report a case of a 20 year-old woman who suffered from acute tubular necrosis after concomitant ingestion of nonsteroidal anti-inflammatory drugs and binge drinking. This acute tubular necrosis is likely to have an hemodynamic origin due to nonsteroidal anti-inflammatory drugs in a patient with volume contraction secondary to binge drinking. The risk appears to be even more important since ethanol has been implicated in tubular necrosis by direct toxicity. This observation underlines the danger in associating nonsteroidal anti-inflammatory drugs and ethanol.

Soluble adhesion molecules in renal transplantation

Serum levels of sICAM-1 and sVCAM-1 adhesion molecules as well as TNF cytokine were measured in 50 kidney transplant recipients [14 patients with stable graft function, 18 patients with acute rejection, 10 patients with CsA toxicity, 6 patients with ATN, and 2 patients with cytomegalovirus (CMV) disease] during the first 3 postoperative weeks. All the patients studied showed, on the first posttransplant day, elevated serum levels of sICAM-1 (260 +/- 53 ng/mL). Interestingly, all the patients with good graft function presented thereafter a reduction of sICAM-1 serum levels close to the normal values (185.2 +/- 40 ng/mL). In contrast, the group of patients with acute allograft rejection showed significantly increased serum levels of sICAM-1 (371.5 +/- 86 ng/mL; p < 0.001), 3-4 days before diagnosis of acute rejection. Although sVCAM-1 levels were increased in both acute graft rejection (2263 +/- 106) and CsA toxicity (1650 +/- 315) patients, such increase was not significant among either group of patients when the group with CsA toxicity was compared with either ATN (1320 +/- 204) or stable renal function (1089 +/- 167). No statistical differences in the levels of TNF were demonstrated between the different groups of patients studied. Our findings demonstrate that quantitative determination of serum sICAM-1 may be of predictive clinical value in transplanted patients with acute renal allograft rejection.

Biocompatible membranes in acute renal failure: prospective case-controlled study

The mortality of critically ill patients with acute renal failure has been halved through intervention by haemodialysis. However, several reports suggest that the course of the disorder may be prolonged by this procedure. Our prospective randomised study was done to see whether the generation of inflammatory mediators by bio-compatible membranes has an adverse effect on the outcome of acute renal failure. 52 patients, similar in age, severity of acute renal failure, general disease status (APACHE II), and management of acute renal failure or its related conditions, were divided into two groups. Haemodialysis was done with cuprophane or polyacrylonitrile membranes. Cuprophane membranes induced intense activation of the complement system (as judged by measurement of C3a) and lipooxygenase pathway (leukotriene B4) resulting in alterations of neutrophil kinetics and function. The cuprophane group had a lower survival rate (38 vs 65%), a higher proportion of patients dying from sepsis (71 vs 40%), required more haemodialysis sessions (12 vs 9), and demonstrated delayed resolution and recovery from acute renal failure than the polyacrylonitrile group. The difference in mortality regarding lethal sepsis as cause of death was statistically significant. Our observations indicate that the outcome of critically ill patients with acute renal failure may be influenced by bio-incompatibility reactions to the dialysis membrane. These results have direct implications for such patients on haemodialysis.

Serum hippuric acid concentration in renal allograft rejection, ureter obstruction, and tubular necrosis

Plasma from 35 renal allograft recipients (21 males and 14 females) was sampled daily and analyzed for hippuric acid (HA) by high-performance liquid chromatography (HPLC) and serum creatinine. Twelve of these patients experienced an acute renal allograft rejection or a ureter obstruction as proven by clinical signs and biopsy, as well as by radiography or ultrasound, respectively. Two patients suffered from tubular necrosis followed by rejection during the postoperative period. Mean serum HA increased by 39.9 mumol/l from baseline (range 20.4-115.5 mumol/l) in patients with acute rejection 3 days after an initial increase that was observed 24 h before the mean serum creatinine increased by 107.1 mumol/l (range 21-193 mumol/l). In cases of ureter obstruction, HA rose by 1.6 mumol/l (range 1-8.2 mumol/l), significantly less than elevations due to rejection. The increase in creatinine, however, amounted to 65.3 mumol/l (range 22-140 mumol/l) and was not different from the change in rejecting patients. Successful antirejection treatment coincided with a decrease in serum HA starting 24 h earlier than the decrease in the serum creatinine concentration. Of special interest was the observation of a parallel decrease in HA with creatinine concentration in patients with tubular necrosis after allotransplantation; HA increased in cases of an additional rejection. Our data suggest that HA, which is excreted by tubular secretion and glomerular filtration, could be a sensitive and early marker of acute allograft rejection. Furthermore, it seems to discriminate between acute renal allograft rejection and ureter obstruction. It might, therefore, be of value in the diagnosis of rejection complicating tubular necrosis after transplantation.

Acute tubular necrosis after interleukin-2 therapy

Immunotherapy with interferon and interleukin-2 is being increasingly used in the treatment of metastatic renal cell cancer. A case is presented in which interleukin-2 (IL2) therapy was complicated by renal tubular necrosis. Renal function returned to normal following aggressive fluid replacement and use of dopamine and cautious diuresis.

Interleukin-6 and neopterin in renal transplant recipients: a longitudinal study

Serum and urine interleukin-6 (IL-6) levels and serum neopterin/creatinine ratios were longitudinally studied in 86 renal transplant recipients until 4 months after transplantation. During acute rejection and acute tubular necrosis (ATN), serum and urine IL-6 levels were elevated compared to during stable transplant function (P < 0.001). During acute rejection, serum IL-6 levels increased at least 2 days before plasma creatinine started to rise (P < 0.05), indicating its early involvement in the rejection process. During cytomegalovirus (CMV) disease, serum, but not urine, IL-6 levels were higher (P < 0.01), and serum neopterin/creatinine values were higher than during stable transplant function, ATN, or acute rejection (P < 0.01). No significant differences with stable transplant function occurred during cyclosporin A toxicity. Measurement of serum IL-6 provided a sensitivity of 84% and a specificity of 85% for the diagnosis of acute rejection episodes not coinciding with ATN. All cases of CMV disease could be diagnosed by measurement of serum neopterin/creatinine, which provided a specificity of 73%.

Plasma fibronectin levels during acute rejection and acute tubular necrosis in renal transplant patients

Fibronectin (Fn), an acute phase glycoprotein synthesized by the liver, has an important immunomodulatory role. We have investigated the changes in plasma Fn in patients after renal transplantation in order to determine whether these changes predict graft injury or rejection episodes. Besides normal healthy controls, healthy pregnant controls, and a trauma control group, we used two groups of chronic renal failure patients as controls: group I, patients with end-stage renal failure (ESRF) on peritoneal dialysis; group II, patients with ESRF on hemodialysis. These were compared with two groups of renal transplant patients: group III, patients 3 months after successful renal transplantation; group IV, patients studied sequentially 10 days immediately posttransplantation. The renal transplant patients were treated with low-dose cyclosporine, azathioprine, and steroids. Citrated plasma samples were collected for Fn assay by a sandwich-type ELISA and for SDS-PAGE analysis and Western blotting. The mean plasma Fn levels were as follows: healthy controls 311.6 SEM, 13.5 micrograms/ml; healthy pregnant controls 357 SEM, 5.9 micrograms/ml; trauma controls 262.3 SEM 31.7, micrograms/ml; group I 169 SEM, 25.1 micrograms/ml; group II 199 SEM, 27.2 micrograms/ml; group III 272 SEM, 21.7 micrograms/ml; group IV 212 SEM, 27.4 micrograms/ml (day 3 postop). There was a significant difference in the plasma Fn levels on day 3 posttransplant between the patients with delayed and immediate renal function (P less than 0.03) (group IV). A significant decrease in plasma Fn levels occurred immediately after steroid therapy was stopped (P less than 0.03) in patients treated for acute rejection. Plasma Fn levels were significantly decreased in the presence of delayed graft function but did not predict rejection.

Erythrocyte deformation in ischemic acute tubular necrosis and amelioration by splenectomy in the dog

Bilateral renal artery occlusion (RAO) for 120 minutes in dogs results in acute tubular necrosis (ATN) and peritubular capillary (PTC) congestion with rapidly deteriorating renal function. We have shown that prior splenectomy minimizes RAO-induced renal functional and histopathologic changes. The purpose of this study was to examine whether this renal protection is due to prevention of red blood cell echinocyte formation and resultant renal PTC congestion. Echinocytes (burr cells) are poorly deformable, impart high viscosity to the blood, and may hinder reperfusion by increasing resistance to renal capillary blood flow. Splenectomized (SPLX) or sham-SPLX dogs were treated with bilateral RAO for 120 minutes. After RAO, renal function and renal blood flow were monitored, and peripheral blood red blood cells were examined at 1 hour and at 24-hour intervals for 96 hours. Renal biopsies were taken 1 hour after RAO and the kidneys removed 96 hours after RAO. The RBCs and renal tissues were studied using scanning electron microscopy. Renal function was assessed by endogenous creatinine clearance. Sham-SPLX animals showed a marked and sustained decrease in creatinine clearance, consistently elevated serum creatinine levels and fractional excretion of sodium, and diffuse ATN and PTC congestion with echinocytes. These animals had a peak in circulating echinocytes 1 hour after RAO (p less than 0.05), which showed an excellent negative correlation with creatinine clearance (r = -0.999; p less than 0.001). On the contrary, SPLX animals had essentially no change in serum creatinine or fractional excretion of sodium, minimal tubular changes, no PTC congestion, and no rise in circulating echinocytes during the 96-hour observation. In vitro treatment of the postischemic red blood cells from sham animals with adenosine-inosine or fresh postischemic plasma from the SPLX animals showed almost complete reversal to discocytes (normal red blood cells), whereas in vitro treatment of postischemic red blood cells from the SPLX animals with fresh postischemic plasma from the sham animals resulted in a marked echinocytic response. We conclude that 1) a marked echinocyte response in the immediate postischemic period is an important mechanism in initiating ischemic ATN, 2) an echinocyte inducing factor may reside in the plasma of spleen-intact animals, and 3) mitigation of ATN and PTC congestion by splenectomy is, at least in part, consequential to attenuated echinocytic response in the immediate postischemic period.

The outcome of delayed graft function in cadaveric renal transplants treated with low dose cyclosporine

Thirty-three consecutive cadaveric renal transplantations performed at the National Taiwan University Hospital from November 1985 to December 1989 were reviewed to determine the effect of early function on the 1-year patient and graft survival rates. Immediate function was present in 17 transplants; delayed graft function with acute tubular necrosis occurred in 16 cases. The 16 transplants with acute tubular necrosis (ATN) were treated with low dose cyclosporine. Among them, 13 patients had delayed function which resolved after 2 to 60 days of hemodialysis, but 3 grafts did not regain function. The allograft survival rate at 1-year was 68.7% for the delayed function group and 88.2% for the immediate function group. This difference was not statistically significant (p greater than 0.05). The 1-year patient survival rate was also not significantly different (87.5% vs 88.2%). There was no relationship between graft loss and duration of ATN. However, the graft survival rate in patients with a serum creatinine level below 2 mg/dL, after recovery either from ATN or non-ATN, was better than that for patients with a serum creatinine level of more than 2 mg/dL. The difference was statistically significant (95.8% vs 50.0%, p less than 0.02). It is concluded that delayed allograft function with acute tubular necrosis does not significantly alter the 1-year survival rates of patients and grafts in low-dose cyclosporine therapy. However, it is deleterious to the 1-year survival rate of an allograft when poor functional recovery occurs in an ATN or non-ATN condition.

Evaluation of renal transplant dysfunction using color Doppler sonography

Color Doppler sonography (CDS) detects changes in renal blood flow that may be useful in evaluating renal transplant dysfunction (RTD). To assess the performance of CDS as a clinical test, we reviewed results from 223 CDS measurements in 130 renal transplant recipients during a 26 month period. Spectral wave forms were characterized by pulsatility index (PI) (maximum frequency shift minus minimum frequency shift divided by mean frequency shift). In 27 individuals with stable renal function, mean PI was 1.80 +/- 0.23 (S.D.). Abnormal PI were subsequently defined as greater than two S.D. more than the mean (PI greater than or equal to 2.3). CDS performed during the early post-transplant period (n = 91) could not differentiate acute tubular necrosis (ATN), obstruction and rejection. Abnormal studies were seen in 35 of 46 instances of ATN and in three of obstruction. In 132 studies done after the postoperative period, CDS became abnormal during rejection episodes in only 45 of 71 instances (sensitivity rate of 63 per cent). When abnormal, CDS was highly suggestive of rejection, however (45 of 49, 92 per cent specificity). Cyclosporine toxicity was not associated with abnormal pulsatility (zero of seven). In 68 instances, CDS and conventional 99mTc DTPA renogram flow studies were performed together within 24 hours. CDS was more sensitive in detecting rejection but the difference did not reach statistical significance (25 of 36 versus 17 of 36). The major advantage of CDS over conventional radionuclide imaging relates to its shorter examination time, lower cost and portable capabilities. CDS will probably become the roentgenologic imaging modality of choice in renal transplantation.

Evaluation of sequential plasma and urinary tumor necrosis factor alpha levels in renal allograft recipients

The macrophage cytokine tumor necrosis factor-alpha is released early in immune activation and may be detected in the peripheral circulation. This study has investigated the occurrence of plasma and urinary TNF in 30 renal allograft recipients. Although circulating TNF may be detected in 20% of pretransplant or normal control samples, levels were significantly elevated during 65% of allograft rejection episodes. Plasma TNF levels did not rise in graft failure due to acute tubular necrosis, but were always highly raised in systemic infection. In contrast, urinary TNF was only detected in association with acute rejection (49%) or tubular necrosis (14%), and no controls had detectable urinary TNF. These findings indicate that evaluation of circulating and excreted TNF may give further insight into the immunobiology of graft rejection.

Erythropoietin deficiency in acute tubular necrosis

Serum erythropoietin (EPO) concentrations were markedly depressed relative to the degree of anaemia in 10 patients with acute tubular necrosis, and remained low long after restoration of excretory renal function as estimated by glomerular filtration rate. Evidence is presented that the low serum EPO level is due to defective synthesis and not to increased catabolism. It is suggested that the predominantly are generatory anaemia found in prolonged cases of acute tubular necrosis, and the slow restoration of red cell mass during recovery, are due to the deficient synthesis of EPO. A positive erythropoietic response in a therapeutic trial with recombinant human erythropoietin (rhEPO) appears to support this hypothesis.

Epidermal growth factor accelerates functional recovery from ischaemic acute tubular necrosis in the rat: role of the epidermal growth factor receptor

1. Severe, ischaemic, acute tubular necrosis was induced in rats by bilateral occlusion of the renal arteries. The experimental group received exogenous epidermal growth factor infused directly into the renal arterial circulation. Serum creatinine concentration was measured daily for 1 week. Epidermal growth factor receptor binding was measured by autoradiography of whole kidney sections. Renal cell proliferation was measured by incorporation of [3H]thymidine into DNA. 2. Serum creatinine concentration increased after acute tubular necrosis with a peak at 48 h and remained elevated above control levels after 7 days. Binding of radiolabelled epidermal growth factor occurred in all regions of the kidney 48 h after ischaemia. Treatment with exogenous epidermal growth factor attenuated the rise in serum creatinine by 4 days after acute tubular necrosis and after 7 days serum creatinine was lower than in animals that did not receive epidermal growth factor. Infusion of epidermal growth factor also increased renal DNA synthesis. 3. The increase in epidermal growth factor binding in the kidney after acute tubular necrosis and the attenuation of the increase in serum creatinine concentration by administration of exogenous epidermal growth factor, suggest a role for epidermal growth factor in recovery from ischaemic damage. The increase in DNA synthesis in response to epidermal growth factor indicates that its effect may be due, at least in part, to accelerated tubular cell proliferation.

Increased hematocrit mitigates ischemic renal damage in the splenectomized dog

Splenectomy (SPLX) prevents ischemic acute tubular necrosis (ATN) and peritubular capillary (PTC) congestion. This study attempts to reverse the protective effect of splenectomy in the ischemic model of ATN by increasing hematocrit before inducing ATN. Sham-SPLX, SPLX, and SPLX dogs given packed red cells to elevate hematocrit by 30% (SPLX-high hematocrit) received bilateral renal artery obstruction (RAO) for 120 minutes. Renal function was tested for 6 days post-RAO. Hematocrit in the SPLX-high hematocrit group was greater (p less than .05) than the SPLX-RAO group but did not differ from the non-SPLX group. All groups had different (p less than .05) serum creatinine levels for 48 hours post-RAO, and untreated animals differed from all the others at 144 hours. Serum creatinine was highest in untreated, lowest in SPLX-high hematocrit, and intermediate in noninfused SPLX animals. The same pattern was observed in blood urea nitrogen, creatinine clearance and renal histopathology. Fractional excretion of sodium in the SPLX groups was six times that in the intact animals (p less than .05), irrespective of hematocrit level. We conclude that increased hematocrit is protective in ischemic ATN, and does not promote PTC congestion or ATN in the SPLX animal. In addition, the protective effect of splenectomy may be mediated, in part, by mechanism(s) that alter sodium transport or osmolar excretion.

[Hepatic and renal toxicity of paracetamol in chronic alcoholic patient]

After taking paracetamol regularly in therapeutic doses, a non-cirrhotic alcoholic subject developed hepatic necrosis and acute renal failure. This case is compared with 13 others found in the literature, and the clinical, biochemical and histological characteristics of such accidents are described. The severity of the acute renal failure is proven by the fact that 50% of the patients had to be put under dialysis. The potentiation of acetaminophen renal and hepatic toxicity by alcohol toxicity is discussed. The principal mechanism of enhancement is the activation of the cytochrome P 450 system associated with depletion of intracellular glutathione.

Combined hepatic and renal injury in alcoholics during therapeutic use of acetaminophen

Combined hepatocellular injury and renal tubular necrosis developed in five alcoholic patients who were receiving acetaminophen therapeutically. Two patients were taking doses prescribed by a physician. The hepatitis was characterized by extremely high serum transaminase values that were maximal on admission. Two patients died, and autopsy disclosed hepatic centrizonal necrosis and acute renal tubular necrosis. The three who survived had clinical features typical of acute tubular necrosis. All five had measurable concentrations of acetaminophen in plasma, although measurements were requested on admission only in two patients. When an alcoholic presents with combined hepatic and renal insufficiency, acetaminophen should be considered as a possible inciting agent. This diagnosis should be considered when serum transaminase levels are markedly elevated and when renal failure is due to acute tubular necrosis.

Tubular dysfunction in the deeply jaundiced patient with hepatorenal syndrome

We examined beta 2-microglobulin (B2MG) excretion, an index of tubular function, in patients with hepatorenal syndrome, in whom tubular function is generally regarded as normal. Urine B2MG was significantly higher in these patients than in control patients with normal serum creatinine concentration. Patients with high urine B2MG concentration had markedly higher serum bilirubin than did patients with normal values (31 +/- 3 vs. 10 +/- 8 mg%, p less than 0.001), whereas prothrombin activity, serum albumin and serum B2MG concentration were similar. A "threshold" serum bilirubin concentration of about 23 mg% differentiated patients with normal and high urine B2MG values. Renal morphology at autopsy was unremarkable in both groups. Tubular dysfunction, manifested by increased urinary excretion of B2MG, occurs in patients with hepatorenal syndrome and deep jaundice. This measurement cannot, therefore, be used to make a diagnosis of acute tubular injury, as due to aminoglycosides, in such patients.

[Disorders of kidney function in hepatic coma]

Renal function was evaluated in 80 patients with hepatic coma stage III-IV (24 patients had acute fulminant hepatic failure, 48 patients chronic hepatic failure, 8 patients had a mixed form). Urea, creatinine and electrolytes were measured in plasma and urine as well as creatinine clearance and sodium/potassium ratio in urine. Renal failure was defined as an increase of serum creatinine above 3 mg/dl. In 15 of the 24 patients with fulminant hepatic failure creatinine clearance was reduced; hyperaldosteronism was present in 13 cases; in 2 patients there was necrosis of the tubulus, in 9 patients overt renal failure. In patients with chronic hepatic failure creatinine clearance was pathological in 36 cases, hyperaldosteronism was diagnosed in 23 cases and necrosis of renal tubules in 3 cases; 8 patients had overt renal failure. In the group with the mixed form of hepatic coma creatinine clearance was pathological in 3 cases, in 6 cases hyperaldosteronism was diagnosed; necrosis of the tubules could not be found in this group; 4 patients had overt renal failure. It is suggested that for treatment of this condition dopamine should be given prophylactically as well as intravenous sodium and water substitution.

Angiotensin-induced myocardial necrosis and renal failure in the rabbit: distribution of lesions and severity in relation to plasma angiotensin II concentration and arterial pressure

Angiotensin II was infused into conscious rabbits at various doses from 0.001 to 0.5 microgram . kg-1 . min-1 for 24 h, and caused multifocal myocardial necrosis, renal tubular necrosis and acute renal failure. The myocardial necroses were found principally in the left ventricle; only at the highest doses of angiotensin II were right ventricular lesions present. The endocardium was not involved and no arterial or arteriolar lesions were seen. Mean arterial plasma angiotensin II concentration during angiotensin infusion was closely correlated with the increase in arterial pressure, the height of the plasma urea at the end of the infusion and the severity of the induced myocardial lesions. The myocardial necroses could be a consequence of the induced hypertension, or a direct effect of angiotensin II, or a combination of effects, although their predominance in the left ventricle suggests high systemic arterial pressure is an important factor. Cardiac lesions were observed with plasma angiotensin II concentrations only some 2 to 3 fold normal values; it is therefore possible that similar myocardial abnormalities might occur as a result of rises in endogenous renin, for example, in experimental or clinical renovascular hypertension.

Bleomycin serum pharmacokinetics as determined by a radioimmunoassay and a microbiologic assay in a patient with compromised renal function

Serum and plasma bleomycin concentrations were determined in a patient with renal dysfunction at two creatinine clearances. The results obtained with a new radioimmunoassay and the microbiologic assay were compared. It was shown: 1) that the clearance of bleomycin from the blood is markedly retarded in severe renal dysfunction, 2) that clearance of bleomycin varies with creatinine clearance, 3) that bleomycin is probably not dialyzable, 4) that determinations on serum and plasma were equivalent, and 5) that the radioimmunoassay and microbiologic assays gave equivalent results (P less than 0.001).

Some serum biochemical changes associated with chloroform-induced renal tubular necrosis in mice

The chloroform--induced renal tubular necrosis is associated with the rise of serum urea, creatinine and potassium. The highest values, observed 24 hours after chloroform administration, are respectively: 75 mg% (norm 32 mg%), 1.75 mg% (norm 0.25 mg%), 6.1 mEq/1 (norm 4.4 mEq/1). They gradually decreased with the progress of renal regeneration. These transient, rather little biochemical deviations justify the good conditions and eventual survival of chloroform-poisoned mice. The contribution of possible glomerular lesions to the disturbed renal function is taken into consideration.