Evaluation of the renal toxicity of heme proteins and their derivatives: a role in the genesis of acute tubule necrosis

A "crush" course on rhabdomyolysis: risk stratification and clinical management update for the perioperative clinician

Rhabdomyolysis, the release of myoglobin and other cellular breakdown products from necrotic muscle tissue, is seen in patients with crush injuries, drug overdose, malignant hyperthermia, muscular dystrophy, and with increasing frequency in obese patients undergoing routine procedures. For the perioperative clinician, managing the resultant shock, hyperkalemia, acidosis, and myoglobinuric acute kidney injury can present a significant challenge. Prompt recognition, hydration, and correction of metabolic disturbances may reduce or eliminate the need for long-term renal replacement therapy. This article reviews the pathophysiology and discusses key issues in the perioperative diagnosis, risk stratification, and management of rhabdomyolysis.

A Case of Evans Syndrome with Acute Hemolysis and Hemoglobin Cast Nephropathy

Patient: Male, 60-year-old

Final Diagnosis: Evans syndrome

Symptoms: Back pain

Medication:—

Clinical Procedure: —

Specialty: Hematology

Mimicking oxygen delivery and waste removal functions of blood

In addition to immunological and wound healing cell and platelet delivery, ion stasis and nutrient supply, blood delivers oxygen to cells and tissues and removes metabolic wastes. For decades researchers have been trying to develop approaches that mimic these two immediately vital functions of blood. Oxygen is crucial for the long-term survival of tissues and cells in vertebrates. Hypoxia (oxygen deficiency) and even at times anoxia (absence of oxygen) can occur during organ preservation, organ and cell transplantation, wound healing, in tumors and engineering of tissues. Different approaches have been developed to deliver oxygen to tissues and cells, including hyperbaric oxygen therapy (HBOT), normobaric hyperoxia therapy (NBOT), using biochemical reactions and electrolysis, employing liquids with high oxygen solubility, administering hemoglobin, myoglobin and red blood cells (RBCs), introducing oxygen-generating agents, using oxygen-carrying microparticles, persufflation, and peritoneal oxygenation. Metabolic waste accumulation is another issue in biological systems when blood flow is insufficient. Metabolic wastes change the microenvironment of cells and tissues, influence the metabolic activities of cells, and ultimately cause cell death. This review examines advances in blood mimicking systems in the field of biomedical engineering in terms of oxygen delivery and metabolic waste removal.

Evans Syndrome Complicated by Intratubular Hemoglobin Cast Nephropathy

Evans syndrome (ES) is a rare autoimmune disorder whose exact pathophysiology is unknown. It is characterized by the simultaneous or subsequent development of autoimmune hemolytic anemia (AIHA) and immune thrombocytopenia (ITP). Intravascular hemolysis, with hemoglobinemia, is known to produce acute kidney injury; however, the development of intratubular hemoglobin casts (hemoglobin cast nephropathy) in the setting of acute hemolysis is uncommon. Likewise, the association of ES and acute renal failure is equally uncommon. We present a case of a 7-year-old girl with ES who developed acute kidney injury in the setting of intravascular hemolysis and had widespread intratubular hemoglobin casts.

Heme Oxygenase-1 and Carbon Monoxide in the Heart: The Balancing Act Between Danger Signaling and Pro-Survival

Understanding the processes governing the ability of the heart to repair and regenerate after injury is crucial for developing translational medical solutions. New avenues of exploration include cardiac cell therapy and cellular reprogramming targeting cell death and regeneration. An attractive possibility is the exploitation of cytoprotective genes that exist solely for self-preservation processes and serve to promote and support cell survival. Although the antioxidant and heat-shock proteins are included in this category, one enzyme that has received a great deal of attention as a master protective sentinel is heme oxygenase-1 (HO-1), the rate-limiting step in the catabolism of heme into the bioactive signaling molecules carbon monoxide, biliverdin, and iron. The remarkable cardioprotective effects ascribed to heme oxygenase-1 are best evidenced by its ability to regulate inflammatory processes, cellular signaling, and mitochondrial function ultimately mitigating myocardial tissue injury and the progression of vascular-proliferative disease. We discuss here new insights into the role of heme oxygenase-1 and heme on cardiovascular health, and importantly, how they might be leveraged to promote heart repair after injury.

Renal Manifestations in Paroxysmal Nocturnal Hemoglobinuria

Paroxysmal nocturnal hemoglobinuria (PNH) is an acquired chronic disorder characterized by a triad of clinical features - hemolytic anemia, pancytopenia, and thrombosis. Not many reports of renal involvement in PNH are available in literature. We present a case series of PNH with renal involvement. We present the data of PNH patients who attended to Departments of General Medicine and Nephrology at a government-run tertiary care institute in South India. The diagnosis of PNH in these patients during initial phase, between 1998 and 2004 was based on sucrose lysis and Ham's test. After 2004, the diagnosis was based on flow cytometry to detect CD59 (membrane inhibitor of reactive lysis), a glycoprotein, and CD55 (decay accelerating factor) in regulation of complement action. The patient data were collected from 1998 to 2014. There were 14 patients of PNH in this period. The mean age was 37 years and the range was 16–68 years. There were eight females. Acute kidney injury (AKI) was noted in six patients. Dialysis was performed in four of them. The mean serum creatinine and urea at the initiation of dialysis were 5.4 ± 0.6 and 64.1 ± 6.1 mg/dl, respectively. The median number of hemodialysis sessions done was four. Renal biopsy was done in four patients. In three patients, the urinalysis and serum chemistry were suggestive of Fanconi syndrome. In our patients, three renal manifestations of PNH were identified. They were AKI, renal vessel thrombosis, and Fanconi syndrome. Chronic renal failure was not identified.

Pheniramine Maleate-Induced Rhabdomyolysis and Aki: Is it Fatal?

Pheniramine maleate is an easily accessible, over-the-counterantihistaminic, which is frequently involved in overdoses. Pheniramine has antimuscarinic effect causing tachycardia, dilated pupils, urinary retention, and dry flushed skin, and decreased bowel sounds, confusion, mild increase in body temperature, cardiac arrhythmias, and seizures at lethal doses. It has not been implicated as an important cause of rhabdomyolysis and acute kidney injury (AKI). Rhabdomyolysis causing AKI is rarely reported in the literature. This case report emphasizes the occurrence of nontraumatic rhabdomyolysis in pheniramine maleate overdose which required hemodialysis. Since there is a lack of a specific antidote, treatment is mainly symptomatic and supportive. We report a fatal case of a young male with a very high dose of consumption of pheniramine maleate (4.077 g), which was complicated by seizures, respiratory depression, nontraumatic rhabdomyolysis, and AKI. Despite hemodialysis, ventilator support, and other intensive supportive care, patient could not survive and death ensued due to multiorgan dysfunction syndrome.

Acute renal failure due to rhabdomyolysis following a seizure

Acute renal failure, oliguric or nonoliguric, is the most common complication of rhabdomyolysis. Rhabdomyolysis should be suspected in patients presenting with states of increased muscular activity, such as seizures, agitation, strenuous muscle exercise, or dystonia. We report an adult who developed acute renal failure associated with rhabdomyolysis following a seizure. The patient made complete recovery with hemodialysis. This report illustrates importance of early recognition of rhabdomyolysis following a seizure episode to prevent the risk of acute renal failure.

Paget-Schrotter syndrome and complications of management

An 18-year-old man presented to the emergency department with an acutely swollen right upper limb having spent the previous day canoeing. Venography confirmed right subclavian venous thrombosis at middle one-third of right clavicle with no evidence of cervical rib or other structural abnormalities. Following heparinisation, catheter directed thrombolysis was performed which restored luminal flow. Postprocedure the patient developed spontaneous small-volume haemoperitoneum and acute renal failure. The patient was admitted to the intensive care unit for haemodialysis and supportive management. The patients' renal function improved and he was discharged well following his 28th day of admission. Paget-Schroetter syndrome or effort thrombosis involves subclavian venous thrombosis associated with strenuous activity of upper extremities. In these cases, catheter directed thrombolysis with first rib resection provides greater patency rate than anticoagulation therapy alone. Acute kidney injury following mechanical thrombolysis is rarely reported in the literature.

Montelukast abrogates rhabdomyolysis-induced acute renal failure via rectifying detrimental changes in antioxidant profile and systemic cytokines and apoptotic factors production

In addition to antiasthmatic effect, the cysteinyl leukotriene receptor 1 (CysLT₁) antagonist montelukast shows renoprotective effect during ischemia/reperfusion and cyclosporine-induced renal damage. Here, we proposed that montelukast protects against rhabdomyolysis-induced acute renal failure. Compared with saline-treated rats, at 48 h following the induction of rhabdomyolysis using intramuscular glycerol (10 ml 50% glycerol/kg), significant elevations in serum levels of urea, creatinine, phosphate and acute renal tubular necrosis were observed. This was associated with elevations in serum Fas, interleukin-10, tumor necrotic factor-alpha, and transforming growth factor-beta1 and renal malondialdehyde and nitrite and detrimental reductions in renal catalase and superoxide dismutase activities. The effects of rhabdomyolysis on renal functional, biochemical and structural integrity and the associated changes in cytokines and Fas levels were abolished upon concurrent administration of montelukast (10 mg/kg i.p.) for 3 days (1 day before and 2 days after induction of rhabdomyolysis). Alternatively, administration of the anti-oxidant, α-tocopherol (400 mg/kg i.m.) for 3 days, succeeded in alleviating renal oxidative stress, but had no significant effect on the circulating levels of most cytokines and partially restored kidney functional and structural damage. Serum level of interleukin-6 was not altered by rhabdomyolysis but showed significant elevations in rats treated with montelukast or α-tocopherol. Collectively, motelukast abrogated functional and structural renal damage induced by rhabdomyolysis via ameliorating renal oxidative stress and modulation of systemic cytokines and apoptotic factors production. The results of this work are expected to open new avenues for early prevention of rhabdomyolysis-induced acute renal failure using selective CysLT₁ antagonists such as montelukast.

Comparing the potential renal protective activity of desferrioxamine B and the novel chelator desferrioxamine B-N-(3-hydroxyadamant-1-yl)carboxamide in a cell model of myoglobinuria

Accumulating Mb (myoglobin) in the kidney following severe burns promotes oxidative damage and inflammation, which leads to acute renal failure. The potential for haem-iron to induce oxidative damage has prompted testing of iron chelators [e.g. DFOB (desferrioxamine B)] as renal protective agents. We compared the ability of DFOB and a DFOB-derivative {DFOB-AdAOH [DFOB-N-(3-hydroxyadamant-1-yl)carboxamide]} to protect renal epithelial cells from Mb insult. Loading kidney-tubule epithelial cells with dihydrorhodamine-123 before exposure to 100 μM Mb increased rhodamine-123 fluorescence relative to controls (absence of Mb), indicating increased oxidative stress. Extracellular Mb elicited a reorganization of the transferrin receptor as assessed by monitoring labelled transferrin uptake with flow cytometry and inverted fluorescence microscopy. Mb stimulated HO-1 (haem oxygenase-1), TNFα (tumour necrosis factor α), and both ICAM (intercellular adhesion molecule) and VCAM (vascular cell adhesion molecule) gene expression and inhibited epithelial monolayer permeability. Pre-treatment with DFOB or DFOB-AdAOH decreased Mb-mediated rhodamine-123 fluorescence, HO-1, ICAM and TNFα gene expression and restored monolayer permeability. MCP-1 (monocyte chemotactic protein 1) secretion increased in cells exposed to Mb-insult and this was abrogated by DFOB or DFOB-AdAOH. Cells treated with DFOB or DFOB-AdAOH alone showed no change in permeability, MCP-1 secretion or HO-1, TNFα, ICAM or VCAM gene expression. Similarly to DFOB, incubation of DFOB-AdAOH with Mb plus H2O2 yielded nitroxide radicals as detected by EPR spectroscopy, indicating a potential antioxidant activity in addition to metal chelation; Fe(III)-loaded DFOB-AdAOH showed no nitroxide radical formation. Overall, the chelators inhibited Mb-induced oxidative stress and inflammation and improved epithelial cell function. DFOB-AdAOH showed similar activity to DFOB, indicating that this novel low-toxicity chelator may protect the kidney after severe burns.

Transitory renal failure following rapid administration of a relatively large amount of hematin in a patient with acute intermittent porphyria in clinical remission

Transitory renal failure occurred in a patient with acute intermittent porphyria in clinical remission following i.v. administration of 1 000 mg hematin. The clinical and biochemical picture suggested "acute tubular necrosis", which was followed by a prompt and complete return of renal function without any late sequelae. The renal failure is thought to have resulted from the presence of circulating free hematin, formed as a result of rapid administration of such a relatively large amount. Such a complication has not occurred in patients given hematin for acute porphyric relapse, in whom much smaller amounts have been infused.

Rhabdomyolysis and acute renal failure following an overdose of doxepine and nitrazepam

A 50-year-old woman developed rhabdomyolysis and myoglobinuric renal impairment after an oral dose of 250 mg nitrazepam and 1,250 mg doxepin. Serum creatinine increased from 70 mumol/l to 472 mumol/l in two days. Serum creatine phosphokinase reached a maximal level of 391 mu kat/l (reference range less than 2.5 mu kat/l) on the third day and serum myoglobin was maximally 910 nmol/l (reference range less than 4.5 nmol/l) on the fourth day after the overdose. Passive and active movements of the knees and ankles became increasingly restricted, but the patient felt no muscle pain. Diuresis decreased to 20-22 ml/hour in spite of repetitive doses of furosemide, but was enforced to greater than 100 ml/hour by vigorous infusion of saline. Haemodialysis was avoided on this regimen. It is suggested that in patients intoxicated with nitrazepam and/or doxepin, rhabdomyolysis should be suspected when a rapidly increasing serum concentration of creatinine is found, even in the absence of muscle pain.

Acute kidney injury caused by intravascular hemolysis after mechanical thrombectomy

BACKGROUND

A 43-year-old African-American female (gravida 5 para 0) with an 8-week intrauterine pregnancy presented to the emergency room with crampy abdominal pain, shortness of breath, and shoulder pain. She had normal renal function on admission. CT angiography of the chest revealed bilateral pulmonary emboli; therefore, the AngioJet (Possis Medical, Inc., Minneapolis, MN) device was used to perform mechanical thrombolysis. The patient subsequently developed hyperkalemia, red urine and anuria.

INVESTIGATIONS

Physical examination, measurement of serum creatinine level and electrolytes, dipstick urinalysis and centrifugation of urine and blood.

DIAGNOSIS

Acute kidney injury due to hemoglobinuria as a result of non-immune-mediated intravascular hemolysis following the use of a percutaneous mechanical thrombectomy device (AngioJet).

MANAGEMENT

Hydration, alkalinization of urine and initiation of hemodialysis (temporarily switched to continuous venovenous hemodiafiltration). Urine output improved after the 20th day of hospitalization, at which point dialysis was discontinued. The patient's renal function completely recovered by day 25.

The syndrome of rhabdomyolysis: complications and treatment

Rhabdomyolysis is a syndrome of skeletal muscle cell damage that leads to the release of toxic intracellular material into the systemic circulation. The pathogenesis of rhabdomyolysis is based on an increase in free ionized calcium in the cytoplasm. Its main complications include (a) acute renal failure, which is triggered by renal vasoconstriction and ischemia, (b) myoglobin cast formation in the distal convoluted tubules, and (c) direct renal toxic effect of myoglobin on the epithelial cells of proximal convoluted tubules. Other major complications include electrolyte disorders, such as hyperkalemia, which may cause cardiac arrhythmias, metabolic acidosis, hyperphosphatemia, early hypocalcemia, and late hypercalcemia. Compartmental syndrome and disseminated intravascular coagulopathy may also emerge. The management of myoglobinuric acute renal failure includes aggressive fluid administration to restore the hypovolemia and urine alkalization. The concomitant electrolyte and metabolic disorders should also be treated appropriately; hemodialysis should be considered when life-threatening hyperkalemia and metabolic acidosis exist. In the case of compartmental syndrome, it is important to monitor the intra-compartmental pressure and to perform fasciotomy, if required. When diagnosed early and if the appropriate treatment is initiated promptly, the complications of rhabdomyolysis are preventable and the syndrome has a good prognosis.

Spectrum of renal involvement in paroxysmal nocturnal hemoglobinuria: report of three cases and a brief review of the literature

Renal involvement in paroxysmal nocturnal hemoglobinuria (PNH) is usually clinically not apparent but, in cases with clinical involvement, varies from reversible acute dysfunction to chronic irreversible damage. We report two cases of acute kidney injury and one case of chronic kidney disease due to PNH. In all three cases a diagnosis of PNH was made after detection of renal dysfunction. The renal involvement was documented on both histology and on imaging studies. Finally, we briefly review the main literature data on renal involvement in PNH.

Recurrent acute renal failure complicating IgG warm-type autoimmune intravascular haemolysis

A 44-year-old woman experienced recurrent episodes of massive intravascular haemolysis complicated by acute oliguric renal failure over a period of 22 years. The haemolysis was induced by IgG warm type autoantibody and complement and responded to corticosteroid therapy. The renal failure was treated effectively by dialysis. To our knowledge, such a life long occurrence of recurrent intravascular haemolysis induced by IgG warm type autoantibodies together with renal failure has not been reported before.

Changes in polymorphonuclear leukocyte elastase concentrations and hemolysis parameters in patients transfused with different blood preparations, and in the blood preparations themselves

PURPOSE

Massive blood transfusion induces hemolysis and increases polymorphonuclear leukocyte elastase (PMNE) concentration. The purpose of this study was to compare hemolysis and PMNE concentrations in massive blood transfusions with three different preparations.

METHODS

In an in vitro study, eight 2-day-old packs of concentrated red blood cells in mannitol, adenine, glucose, phosphate, and citrate solution (MAP-CRC); concentrated red blood cells in citrate, phosphate, and glucose solution (CPD-CRC); or whole blood in citrate, phosphate, and glucose solution (WB) were stored at 4 degrees C. Supernatant concentrations of total and free hemoglobin, total haptoglobin, and PMNE were measured. In an in vivo study, 24 surgical patients with expected bleeding exceeding 3000 ml were transfused with CPD-CRC or MAP-CRC with fresh frozen plasma, or with WB. Platelet count, prothrombin time, activated partial thromboplastin time, serum total and free hemoglobin, and total haptoglobin and plasma PMNE concentrations were measured.

RESULTS

In the in vitro study, total and free hemoglobin concentrations were significantly higher in CPD-CRC than in the other two preparations. Total haptoglobin concentration was highest in the order of WB > MAP-CRC > CPD-CRC. The PMNE concentration was significantly higher in WB than in the other two preparations. In the in vivo study, at 3000-ml transfusion, total and free hemoglobin concentrations were significantly lower and activated partial thromboplastin time was longer in the patients with MAP-CRC compared with values in the other two groups. The PMNE concentration was significantly higher in the order of the WB > CPD-CRC > MAP-CRC groups.

CONCLUSION

During the storage of MAP-CRC, CPD-CRC, and WB, CPD-CRC had the greatest hemolysis and WB had the highest concentration of PMNE. Patients who received massive blood transfusion of MAP-CRC had the least hemolysis and the lowest concentration of PMNE.

Paroxysmal cold haemoglobinuria leading to acute renal failure: A case report

Paroxysmal cold haemoglobinuria (PCH) is a form of autoimmune haemolytic anaemia (AIHA) characterised by sudden onset of haemoglobinuria either spontaneously or following exposure to cold. It was previously believed to be a rare form of AIHA, but is now thought to be responsible for up to 40% of cases of acute transient haemolytic anaemia in children1 following viral infections. Although the anaemia can be severe, illness is characteristically of short duration and does not recur. Published reports of PCH in children leading to renal impairment are rare, with supportive management only being used in affected cases.2, 3 We describe the case of a 2-year-old boy who developed acute renal failure (ARF) secondary to PCH, requiring peritoneal dialysis, where the early institution of plasma exchange was associated with rapid recovery of renal function.

The effect of combining intermittent hemodiafiltration with forced alkaline diuresis on plasma myoglobin in rhabdomyolysis

BACKGROUND

Our aim was to examine the effect of combining intermittent hemodiafiltration (HDF) with forced alkaline diuresis on plasma myoglobin in rhabdomyolysis.

METHODS

This was a prospective, randomized, controlled, cross-over study. Sixteen rhabdomyolysis patients with plasma myoglobin concentrations above 10,000 microg/l were randomized. Forced alkaline diuresis was started immediately after allocation and continued throughout the study. HDF, which lasted for 4 h, was started in group A immediately after allocation and in group B 4 h later. The primary analysis was intention-to-treat by repeated measures analysis of variance and Mann-Whitney U-test.

RESULTS

The percentage elimination of myoglobin from the circulation during HDF differed significantly from that during alkaline diuresis (28.1% vs. 14.2%, respectively; P < 0.01). The mean decrease in plasma myoglobin concentration during HDF [9731 microg/l; 95% confidence interval (CI), 3672-5345 microg/l] and forced alkaline diuresis (3646 microg/l; 95% CI, 1260-6032 microg/l) did not show a statistically significant difference (P= NS). The mean total amount of myoglobin found in the ultrafiltrate was 58.4 mg.

CONCLUSION

The percentage myoglobin decrease during combined HDF and forced alkaline diuresis was higher than that during forced alkaline diuresis alone. Renal replacement therapy with filtration techniques may be considered for the clearance of myoglobin from plasma when urine alkalinization is not successful.

Electrostatic field can preserve red blood cells in stored blood preparations

PURPOSE

During the storage of red blood cell concentrates (CRCs), red blood cells are progressively destroyed and free hemoglobin and potassium concentrations increase. In this study, we focused on an electrostatic field that maintains food freshness without freezing, even at less than the freezing point. We hypothesized that the storage of CRCs under an electrostatic field could keep red blood cells in better condition than conventional storage.

METHODS

Each of 15 packs of 2-day-old CRCs, preserved in MAP (mannitol, adenine, glucose, phosphate, and citrate) solution (MAP-CRC) was divided into 4 smaller equal-size packs and stored at 4 degrees C in a newly developed refrigerator that can generate an electrostatic field. Each group was exposed to a 0-, 500-, 1500-, or 3000-volt (V) electric field for 30 days. Concentrations of free hemoglobin, total haptoglobin, sodium (Na), and potassium (K), and the pH, were measured in the supernatant.

RESULTS

Haptoglobin was not detected. The Na concentration decreased with time but was significantly lower in the 0-V than in the 500-, 1500-, and 3000-V groups. K and free hemoglobin concentrations increased with time, with significantly higher values in the 0-V than in the 500-, 1500-, and 3000-V groups. The pH decreased in the 500-, 1500-, and 3000-V groups, while it did not change in the 0-V group. The pH decrease was smaller in the 500-V than in the 1500- and 3000-V groups.

CONCLUSION

Storing MAP-CRC in an electrostatic field of 500 to 3000 V could decrease hemolysis in the preparation. Considering the lower pH decrease, 500 V might be the field of choice.

Acute pediatric rhabdomyolysis: causes and rates of renal failure

OBJECTIVES

The goals were to (1) compare the causes, clinical presentation, and prevalence of acute renal failure in pediatric rhabdomyolysis with the published data for adults; (2) determine predictors of acute renal failure in pediatric patients with rhabdomyolysis; and (3) explore the relationship of acute renal failure with treatment modalities such as fluid and bicarbonate administration.

METHODS

We performed a retrospective chart review to identify patients with creatinine kinase levels of > 1000 IU/L who were treated in the emergency department of a tertiary pediatric hospital between 1993 and 2003, and we constructed regression models.

RESULTS

Two hundred ten patients were studied. One hundred ninety-one patients met study eligibility (128 male and 63 female), with a median age of 11 years. The most common documented symptoms were muscle pain (45%), fever (40%), and symptoms of viral infection (39%). The most common causes of pediatric rhabdomyolysis were viral myositis (38%), trauma (26%), and connective tissue disease (5%). Six of 37 patients with creatinine kinase levels of > or = 6000 IU/L had previously undiagnosed dermatomyositis or hereditary metabolic disease, compared with 10 of 154 patients with creatinine kinase levels of 1000 to 5999 IU/L. Nine of 191 patients developed acute renal failure. None of 99 patients with initial urinary heme dipstick results of < 2+ developed acute renal failure, compared with 9 of 44 patients with urinary heme dipstick results of > or = 2+. Higher initial creatinine kinase levels and higher fluid administration rates were associated with higher maximal creatinine levels.

CONCLUSIONS

The cause of acute pediatric rhabdomyolysis is different from that of adult rhabdomyolysis. The risk of acute renal failure in children is much less than the risk reported for adults.

Methyl-beta-cyclodextrin induces vasopressin-independent apical accumulation of aquaporin-2 in the isolated, perfused rat kidney

Vasopressin increases urine concentration by stimulating plasma membrane accumulation of aquaporin-2 (AQP2) in collecting duct principal cells, allowing bulk water flow across the collecting duct from lumen to interstitium down an osmotic gradient. Mutations in the vasopressin type 2 receptor (V2R) cause hereditary X-linked nephrogenic diabetes insipidus (NDI), a disease characterized by excessive urination and dehydration. Recently, we showed that inhibition of endocytosis by the cholesterol-depleting drug methyl-beta-cyclodextrin (mbetaCD) induces plasma membrane accumulation of AQP2 in transfected renal epithelial cells overexpressing epitope-tagged AQP2. Here, we asked whether mbetaCD could induce membrane accumulation of AQP2 in situ using the isolated, perfused kidney (IPK). By immunofluorescence and electron microscopy, we show that AQP2 was shifted from a predominantly intracellular localization to the apical membrane of principal cells following 1-h perfusion of Sprague-Dawley rat kidneys with 5 mM mbetaCD. Quantification of staining revealed that the intensity of AQP2 was increased from 647+/-114 (control) to 1,968+/-299 units (mbetaCD; P<0.001), an effect similar to that seen after perfusion with 4 nM dDAVP (1,860+/-298, P<0.001). Similar changes were observed following mbetaCD perfusion of kidneys from vasopressin-deficient Brattleboro rats. No effect of mbetaCD treatment on the basolateral distribution of AQP3 and AQP4 was detected. These data indicate that AQP2 constitutively recycles between the apical membrane and intracellular vesicles in principal cells in situ and that inducing apical AQP2 accumulation by inhibiting AQP2 endocytosis is a feasible goal for bypassing the defective V2R signaling pathway in X-linked NDI.

Rhabdomyolysis after cerebral perfusion pressure-guided management in severe head injury

Intravenous infusion of norepinephrine is usually effective and safe to maintain adequate cerebral perfusion pressure for the management of posttraumatic intracranial hypertension. We report the case of a 17-year-old woman who suffered from traumatic intracranial bleeding and hypotension; she developed rhabdomyolysis, myoglobinuria and acute renal failure after receiving high dose norepinephrine postoperatively. Hemodialysis was begun 3 days after the onset of myoglobinuria when acute renal failure was noted, despite aggressive fluid supplementation and alkaline diuresis. After aggressive treatment and dialysis, the patient's myoglobinuria and rhabdomyolysis gradually declined. Her kidneys eventually regained normal function. We consider that systemic hypotension may have been the leading cause for development of rhabdomyolysis, and vasoconstrictors such as norepinephrine aggravated this. We emphasise the potentially devastating consequences of rhabdomyolysis when a large dose of norepinephrine is given for the treatment of hypotension during cerebral perfusion pressure-guided management.

Nitric Oxide Scavenging by the Cobalamin Precursor Cobinamide

Nitric oxide (NO) is an important signaling molecule, and a number of NO synthesis inhibitors and scavengers have been developed to allow study of NO functions and to reduce excess NO levels in disease states. We showed previously that cobinamide, a cobalamin (vitamin B12) precursor, binds NO with high affinity, and we now evaluated the potential of cobinamide as a NO scavenger in biologic systems. We found that cobinamide reversed NO-stimulated fluid secretion in Drosophila Malpighian tubules, both when applied in the form of a NO donor and when produced intracellularly by nitricoxide synthase. Moreover, feeding flies cobinamide markedly attenuated subsequent NO-induced increases in tubular fluid secretion. Cobinamide was taken up efficiently by cultured rodent cells and prevented NO-induced phosphorylation of the vasodilator-stimulated phosphoprotein VASP both when NO was provided to the cells and when NO was generated intracellularly. Cobinamide appeared to act via scavenging NO because it reduced nitrite and nitrate concentrations in both the fly and mammalian cell systems, and it did not interfere with cGMP-induced phosphorylation of VASP. In rodent and human cells, cobinamide exhibited toxicity at concentrations > or =50 microM with toxicity completely prevented by providing equimolar amounts of cobalamin. Combining cobalamin with cobinamide had no effect on the ability of cobinamide to scavenge NO. Cobinamide did not inhibit the in vitro activity of either of the two mammalian cobalamin-dependent enzymes, methionine synthase or methylmalonyl-coenzyme A mutase; however, it did inhibit the in vivo activities of the enzymes in the absence, but not presence, of cobalamin, suggesting that cobinamide toxicity was secondary to interference with cobalamin metabolism. As part of these studies, we developed a facile method for producing and purifying cobinamide. We conclude that cobinamide is an effective intra- and extracellular NO scavenger whose modest toxicity can be eliminated by cobalamin.

The effects of dichloroacetate in a rabbit model of acute hind-limb ischemia and reperfusion

BACKGROUND

Dichloroacetate (DCA) is a drug that allows pyruvate dehydrogenase to remain active under anaerobic conditions by inhibiting the inactivating enzyme, pyruvate dehydrogenase kinase. We hypothesize that the administration of DCA during acute limb ischemia may have a beneficial effect by reducing the severity of anaerobic metabolism and lessening the irreversible injury.

STUDY DESIGN

We studied a rabbit model using unilateral ligation of the iliac artery or femoral artery to evaluate two degrees of ischemia. After 2 hours of hind-limb ischemia, the animals were administered IV DCA (15 mg/kg) or an equivalent volume of saline.

RESULTS

Higher serum lactate levels were seen after high compared to low ligation in control animals consistent with more severe ischemia. DCA treatment significantly reduced serum lactate levels after both high and low ligation. Similarly, the rise in percentage end-tidal CO(2) after reperfusion was less after DCA. All animals regained hind-limb function after the procedure, but ischemia or reperfusion resulted in appreciable muscle necrosis (> 10% area) in 50% of high- and 22% of low-ligation control animals. DCA treatment eliminated significant muscle necrosis in 100% of high-ligation animals. Muscle histology was similar in control and DCA-treated low-ligation animals.

CONCLUSIONS

Treatment with DCA during acute arterial occlusion did significantly lower markers of anaerobic metabolism and reduced muscle necrosis in a rabbit model of acute hind-limb ischemia. DCA delivery through collateral blood flow may prolong the ischemia time interval before the onset of irreversible muscle injury and potential limb loss.

Alcohol misuse and renal damage

Recent clinical and experimental studies have demonstrated that the habitual consumption of large amounts of ethanol has deleterious effects on the kidney. A variety of tubular defects have been described in patients with chronic alcoholism. Evidence is emerging that tubular dysfunction has an important pathophysiological role in a wide range of electrolyte and acid-base disturbances commonly observed in these patients, and possibly in alcohol-induced bone disease. These renal abnormalities are often reversible, disappearing with abstinence. However, since 1990 a few cases of a syndrome of acute tubular necrosis due to binge drinking of ethanol in the absence of other evident nephrotoxic mechanisms, or in association with the use of nonsteroidal anti-inflammatory drugs, have been reported. A link between glomerulonephritis and alcoholism has become evident. IgA nephropathy has been demonstrated at autopsy in 64% of chronic alcoholics and, more recently, the association between alcoholism and postinfectious glomerulonephritis has been described. Structural and functional abnormalities of the kidney are reported with increasing frequency in the fetal alcohol syndrome seen in children who have been prenatally exposed to ethanol. In addition, over the last few years experimental studies in vitro or in animal models have provided information about the biochemical and molecular basis of alcohol-induced injury to kidney. It is hoped that future experimental and clinical research will provide us with a more comprehensive knowledge of the mechanisms of renal damage in alcohol misuse.

Hemolysis in stored red blood cell concentrates: modulation by haptoglobin or ulinastatin, a protease inhibitor

OBJECTIVE

Polymorphonuclear leukocyte elastase may injure various tissues. The release of polymorphonuclear leukocyte elastase induced by various stimuli was reported to be inhibited by a protease inhibitor, ulinastatin. In stored blood preparations, polymorphonuclear leukocyte elastase increases depending on the storage days as hemolysis increases. We hypothesized that polymorphonuclear leukocyte elastase might be one of the factors inducing hemolysis in stored blood. Haptoglobin binds to free hemoglobin to reduce hemolysis. The purpose of the study was to investigate the effects of ulinastatin on hemolysis in blood preparations in comparison with haptoglobin.

DESIGN

In vitro study.

SETTING

Laboratory in a university hospital.

SUBJECTS

Nine 2-day-old packs of red blood cell concentrates (CRC) in 400 mL each of mannitol, adenine, glucose, phosphate, and citrate (MAP) (MAP-CRC) from the Japan Red Cross Society.

INTERVENTIONS

Each MAP-CRC was divided into three different packs of equal amount and was treated with 10 mL of saline (control group), 200 units of haptoglobin, or 50,000 units of ulinastatin. They were stored at 4 degrees C.

MEASUREMENTS AND MAIN RESULTS

Supernatant concentrations of total and free hemoglobin, total haptoglobin, polymorphonuclear leukocyte elastase, and potassium were measured for 25 days. Free haptoglobin concentration was calculated. Total and free hemoglobin concentrations increased significantly depending on the storage days in the control group, whereas haptoglobin and ulinastatin groups showed no increase. Total and free haptoglobin concentrations were significantly higher in the haptoglobin group than in the other two groups. Free haptoglobin concentrations were 0 after 5 days of storage in the control and ulinastatin groups. Polymorphonuclear leukocyte elastase concentrations increased with the increase in storage days without any differences among the three groups. Potassium concentration increased according to the storage and showed the highest value in the control group.

CONCLUSIONS

Adding haptoglobin or ulinastatin to MAP-CRC was useful to suppress hemolysis during storage of the preparation. The polymorphonuclear leukocyte elastase might not be involved in the mechanisms of hemolysis in MAP-CRC stored for 25 days.

Pathophysiology and management of renal insufficiency in the perioperative and critically ill patient

Acute renal failure remains a common, devastating complication of the postoperative period and in the critically ill patient. The most common cause is the progression of prerenal insufficiency to ATN. Despite improved understanding of the pathogenic mechanisms, including impaired hemodynamic autoregulation, medullary hypoxia, and proximal tubular obstruction and transtubular backleak, the treatment, to date, remains largely supportive. Avoidance by ensuring hemodynamic stability, with provision of adequate renal perfusion, provides the best means for minimizing the complications of this organ dysfunction.

Free hemoglobin concentrations in patients receiving massive blood transfusion during emergency surgery for trauma

PURPOSE

To determine free hemoglobin concentration in patients who received massive blood transfusion during emergency surgery for trauma with consideration of the storage of the transfused blood.

METHODS

Fifteen patients undergoing emergency surgery for multiple trauma and who received blood transfusion of more than 5000 mL were studied. Transfusion of the stored whole blood in citrate-phosphate glucose solution using a micropore filter was started before surgery. Serum concentrations of hemoglobin (total:THb and free:fHb) and total haptoglobin (THp) were measured until 5,000 mL of blood had been transfused. Serum free haptoglobin (fHp) concentration was calculated. The correlation between the changes in hemoglobin or haptoglobin concentrations and total storage days of the transfused blood was analyzed by a simple regression analysis.

RESULTS

Free hemoglobin was detected after 2,000 mL transfusion. The THp and fHp decreased after 1,000 mL transfusion. Total storage time (days) of transfused blood had correlated with the changes of THp (P < 0.0001) and fHp (P = 0.0027) but not with the changes of THb (P = 0.984) and fHb (P = 0.834).

CONCLUSION

After blood transfusion during surgery for trauma, serum haptoglobin concentration decreased with transfusion of > or = 1,000 mL of whole blood with mean storage time of 12.2 dy. Free hemoglobin was detected after 2,000 mL transfusion when THp decreased to 1,000 mgxL(-1). Serum haptoglobin concentrations correlated negatively with storage time (days) of transfused blood.

Myoglobinuria

Myoglobinuria refers to an abnormal pathologic state in which an excessive amount of myoglobin is found in the urine, imparting a cola-like hue, usually in association with myonecrosis and a clinical picture of weakness, myalgias, and edema. Myoglobinuria is produced by multiple causes: any condition that accelerates the use or interferes with the availability of oxygen or energy substrates to muscle cells can result in myoglobinuria, as can events that produce direct muscle injury, either mechanical or chemical. Acute renal failure is the most serious complication, which can be prevented by prompt, aggressive treatment. In patients surviving acute attacks, recovery of muscle and renal function is usually complete.

Rhabdomyolysis and acute renal failure in intensive care unit

Rhabdomyolysis is common clinical and laboratory syndrome resulting from skeletal muscle injury and acute renal failure is the most important complication. Acute renal failure is common in critically ill medical patients. The aim of our study was to determine the prevalence of rhabdomyolysis induced acute renal failure in these patients and to established the prognosis of critically ill patients with acute renal failure and rhabdomyolysis. In the study were included 1557 patients treated in our medical intensive care unit. Seventy-three patients had criteria for acute renal failure. Twelve of them (16.4%) had rhabdomyolysis, eight were women and four were men (average age was 71 years). Sixty-one patients (83.6%) had acute renal failure without rhabdomyolysis, 33 were women and 28 were men (average age was 69 years). We found no difference in age and sex between patients with acute renal failure with or without rhabdomyolysis. Ten patients (83.3%) with rhabdomyolysis and 39 patients (63.9%) without rhabdomyolysis had multiorgan failure syndrome. In patients with rhabdomyolysis, the number of failing organs were statistically significantly higher (p < 0.027). Nine patients (75%) with rhabdomyolysis and 27 patients (44.3%) without rhabdomyolysis died. Mortality was statistically significantly higher (p < 0.05) in patients with rhabdomyolysis. Rhabdomyolysis with acute renal failure was frequently observed in patients treated in our medical intensive care unit. Multiorgan failure syndrome was common in these patients and mortality was higher compared to patients without rhabdomyolysis.

Perioperative renal dysfunction and cardiovascular anesthesia: concerns and controversies

In patients with renal disease undergoing cardiovascular surgery, perioperative management continues to be a challenge. Traditional answers have turned into new questions with the introduction of new agents and the redesign of old techniques. For ARF prevention, early recognition of pending deleterious compensatory changes is critical. Theoretically, therapeutic intervention designed to prevent ischemic renal failure should be designed to preserve the balance between RBF and oxygen delivery on one hand and oxygen demand on the other. Maintenance of adequate cardiac output distribution to the kidney is determined by the relative ratio of renal artery vascular resistance to systemic vascular resistance. Indeed, it should not be surprising to learn that norepinephrine (despite its vasoconstricting effect) has been reported to have no deleterious renal effects in patients with low systemic vascular resistance. Until recently, strategies for the treatment of ARF have been directed to supportive care with dialysis (to allow tubular regeneration). Various therapeutic maneuvers have been introduced in an attempt to accelerate the recovery of glomerular filtration, including dialysis, nutritional regimens, and new pharmacologic agents. A recent small prospective trial of low-dose dopamine in the prophylaxis of ARF in patients undergoing abdominal aortic aneurysm repair showed no benefit in those patients receiving dopamine. Conversely, the effects of intravenous atrial natriuretic peptide in the treatment of patients with ARF appear to offer benefit in patients with oliguria. Among 121 patients with oliguric renal failure, 63% of those who received a 24-hour infusion of atrial natriuretic peptide required dialysis within 2 weeks compared with 87% who did not. Whether this effect will be borne out in the future remains to be determined. The administration of epidermal growth factor after induction of ischemic ARF in rats has been shown to enhance tubular regeneration and accelerate recovery of kidney function. Human growth factor administration has been shown to increase GFR 130% greater than baseline in patients with chronic renal failure, but no data for clinical ARF have been reported. In addition, there have been significant improvements in dialysis technology in the treatment of ARF. Modern dialysis uses bicarbonate as a buffer as opposed to acetate, which reduces cardiovascular instability, and has more precise regulation of volume removal. Dialysate profiles and temperatures improve hemodynamics and reduce intradialytic hypotension. Techniques of hemodialysis without anticoagulation have reduced bleeding complications. Finally, dialysis membranes activate neutrophils and complement less with the biocompatible membranes used today that reduce recovery time and dialysis treatment. Evidence indicates that activation of complement and neutrophils by older dialysis membranes caused a greater incidence of hypotension, adding to ischemic renal injury. It remains to be determined whether early and frequent dialysis with biocompatible membranes, as well as other therapeutic interventions, will increase the survival of patients with perioperative ARF.

Effect of nitric oxide on hemoprotein-catalyzed oxidative reactions

Hemoglobin or myoglobin-catalyzed oxidation reactions have been suggested to initiate and/or exacerbate tissue injury associated with a variety of pathological conditions including post-ischemic tissue injury, hemorrhagic disorders, and chronic inflammation. In the present study, we investigated what effect different fluxes of nitric oxide (NO) have on hemoprotein-catalyzed oxidation reactions in vitro. The hypoxanthine/xanthine oxidase system was used to generate both O2- and H2O2, whereas the spontaneous decomposition of the spermine/NO adduct was used to generate NO at a known and constant rate. We assessed the ability of myoglobin (Mb) or hemoglobin (Hb) to oxidize dihydrorhodamine (DHR) to rhodamine (RH) in the presence of O2-/H2O2 and/or NO. In the presence of a constant flux of O2- and H2O2 (1 nmol/min each), 500 nM MetMb (Fe3+) stimulated DHR oxidation from normally undetectable levels to approximately 35 microM. This oxidation reaction was inhibited by catalase but not SOD, suggesting the formation of the ferryl-hemoprotein adduct (Fe4+). Equimolar fluxes of O2-, H2O2, and NO increased further DHR oxidation to approximately 50 microM. The 15 microM increase in DHR oxidation was independent of heme concentration and was inhibited by SOD. This suggested that equal fluxes of O2- and NO interact to yield a potent oxidant such as peroxinitrite (OONO-) which together with Mb-Fe4+ oxidizes DHR. Further increases in NO fluxes significantly inhibited DHR oxidation (80%) via the NO-dependent inhibition of Mb-Fe4+ formation. Additional studies using methemoglobin (Hb-Fe3+)-catalyzed oxidative reactions yielded virtually identical results. We conclude that in the presence of a hemoprotein such as myoglobin or hemoglobin, NO may promote or inhibit oxidation reactions depending upon the relative fluxes of O2-, H2O2, and NO.

Effect of polyethylene glycol conjugated bovine hemoglobin in both top-load and exchange transfusion rat models

The purpose of this study was to determine the effect of the hemoglobin based oxygen carrier, polyethylene glycol conjugated bovine hemoglobin (PEG-Hb) on the physiology of the rat. This study was divided into the following 3 parts: pharmacokinetics, cardiovascular, and histopathology. Pharmacokinetic studies evaluated the PEG-Hb circulatory life and the resultant effect on urine composition. Telemetric intravascular blood pressure probes monitored the heart rate and mean arterial pressure. Renal arterial blood flow was determined by intraoperative perivascular ultrasound. Tissue histology was evaluated for both time and model dependent responses. The mean circulatory half-life of PEG-Hb was 17.7+/-0.3 h. Proteinuria and hemoglobinuria were greatly reduced with PEG conjugation. PEG-Hb treated rats produced 8.5 times and 49 times less proteinuria and hemoglobinuria, respectively, than unmodified bovine Hb treated animals. The mean arterial pressure (MAP) in PEG-Hb treated rats was insignificantly different from sham controls undergoing a 30% exchange transfusion while dextran caused an initial reduction and bovine Hb produced a prolonged elevation in the MAP. In these same anesthetized rats, PEG-Hb slightly decreased the heart rate while dextran caused an increase and bovine Hb had no effect. In addition, PEG-Hb was able to maintain the renal arterial blood flow while both Ringer's lactate and bovine Hb caused a reduction in the blood flow. Finally, PEG-Hb treated rats showed a dose and time dependent formation of vacuoles within the renal proximal convoluted tubules and splenic macrophages in both top-load and exchange transfusion models, but no other morphological changes. In conclusion, PEG-Hb had a relatively long vascular persistence that did not cause any significant alterations in the urinalysis, cardiovascular function, or tissue histopathology in the rat.

The impact of polyethylene glycol conjugation on bovine hemoglobin's circulatory half-life and renal effects in a rabbit top-loaded transfusion model

This study compares the effects of polyethylene glycol (PEG) modified bovine hemoglobin on vascular half-life and renal function in rabbits to those of unmodified bovine hemoglobin. Renal function was assessed by the measurement of the glomerular filtration rate, urinalysis, blood chemistries, hemoglobin (Hb) excretion rates, and tissue histology. The influence of infusion rates on hemoglobin excretion rates and organ morphology was also examined. The mean half-life of unmodified bovine hemoglobin was 3.0 +/- 0.1 (mean +/- SEM) h, which was extended 14-fold to 43.2 +/- 1.7 h following PEG conjugation. The glomerular filtration rate, urinalysis, and blood chemistries were not greatly affected by either the unmodified bovine hemoglobin or the PEG modified bovine hemoglobin. However, unmodified bovine hemoglobin did demonstrate significant hemoglobinuria (Hb excretion levels in excess of 1.0% of the infused dose [p < 0.05]) at all infusion rates given while PEG modified bovine hemoglobin did not. In addition, histological examination by light microscopy indicated that the most severe morphological changes occurred in animals that received unmodified bovine hemoglobin. This data suggests that PEG modification of bovine hemoglobin significantly reduced some of the adverse effects of bovine hemoglobin on renal physiology and morphology.

Severe rhabdomyolysis with good recovery in a patient with head injury: case report

OBJECTIVE AND IMPORTANCE

We report a case of head injury, in which a hyperosmolar state evolved during the course of treatment, complicated by severe rhabdomyolysis and acute renal failure, which subsequently resulted in a good recovery after intensive supportive treatment. To our knowledge, such high levels of creatine kinase in a patient with head injury and rhabdomyolysis have not been reported.

CLINICAL PRESENTATION AND INTERVENTION

A 19-year-old male patient with head injury sustained a compound fracture of the frontal region. He received a hyperosmolar agent to treat brain edema and developed a hyperosmolar state and diabetes insipidus 1 day after the accident. There were no obvious associated injuries at physical examination. After admission to the intensive care unit, the patient developed myoglobinuria and rhabdomyolysis; serum creatine kinase was elevated to a peak of 650,000 IU/L. Four days later, acute renal failure was noted. The patient's myoglobinuria and rhabdomyolysis gradually declined, and he eventually recovered from acute renal failure after supportive treatment and dialysis.

CONCLUSION

We postulate that the hyperosmolar state of the patient was the major cause of his severe rhabdomyolysis. Associated hypokalemia and hypophosphatemia are also predisposed to rhabdomyolysis. The most serious complication in rhabdomyolysis is acute renal failure, but most patients who receive supportive treatment and can survive despite the complications can expect to have normal renal function restored.

Acute renal failure due to rhabdomyolysis in diabetic patients

We report a 32-year-old Black man, admitted to the ICU with coma and severe metabolic disturbances due to diabetic ketoacidosis. During the admission, rhabdomyolysis and acute renal failure (ARF) were diagnosed. After metabolic control and gradual decrease of creatine kinase levels, he presented a progressive improvement of renal function. We emphasize nontraumatic rhabdomyolysis as a poorly recognized pathogenetic factor for ARF in diabetic ketoacidosis and suggest that a better understanding of its mechanisms and an early application of protective measures is necessary.

Effects of nifedipine and platelet activating factor antagonist (BN 52021) in glycerol-induced acute renal failure in rats

We studied the actions of nifedipine and the platelet activating factor (PAF) antagonist BN 52021 on renal and tubular function in glycerol-induced acute renal failure (Gly-ARF). The tubular handling of sodium was evaluated through the lithium clearance method in awake rats in metabolic cages. The sequential analysis of tubular function 3, 6, 12, and 24 h after Gly-ARF showed a sharp decrease in fractional proximal Na reabsorption (FPRNa)--control 74.1 +/- 12.5%, 3 h: 79.5 +/- 6.0%; 6 h: 41.8 +/- 15.9%; 12 h: 22.9 +/- 17.9%; and 24 h: 31.1 +/- 16.2% (p < 0.001) while fractional distal Na reabsorption (FDRNa) did not change during the study. The effect of nifedipine (20 mg/kg p.o.) and BN 52021 (1 mg/kg i.p.) were evaluated 24 h after the induction of Gly-ARF. Both drugs attenuated the reduction in creatinine clearance (control 431.8 +/- 108.2, glycerol 96.7 +/- 43.8, glycerol plus nifedipine 264.9 +/- 103.5, and glycerol plus BN 52021 188.9 +/- 69.8 microL/min/100 g, p < 0.001). However, only nifedipine could keep FPRNa higher than untreated rats (58.3 +/- 13.2 vs. 31.1 +/- 16.2%, p < 0.05) and reduced the tubular necrosis on histologic semiquantitative analysis. Our data showed that nifedipine and BN 52021 could protect against filtration failure in Gly-ARF but that only nifedipine reduced the proximal tubular lesion.