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Abstract
Acute kidney injury (AKI), previously referred to as acute renal failure, represents a common and devastating problem in clinical medicine. Despite significant improvements in therapeutics, the mortality and morbidity associated with AKI remain high. A major reason for this is the lack of early markers for AKI, and hence an unacceptable delay in initiating therapy. Fortunately, the application of innovative technologies such as functional genomics and proteomics to human and animal models of AKI has uncovered several novel biomarkers and therapeutic targets. The most promising of these are chronicled in this review. These include the identification of biomarker panels in plasma (neutrophil gelatinase-associated lipocalin and cystatin C) and urine (neutrophil gelatinase-associated lipocalin, kidney injury molecule-1, interleukin-18, cystatin C, alpha1-microglobulin, Fetuin-A, Gro-alpha, and meprin). It is likely that the AKI panels will be useful for timing the initial insult, and assessing the duration and severity of AKI. It is also probable that the AKI panels will distinguish between the various etiologies of AKI and predict clinical outcomes. It will be important in future studies to validate the sensitivity and specificity of these biomarker panels in clinical samples from large cohorts and from multiple clinical situations. Such studies will be facilitated markedly by the development of commercial tools for the reproducible measurement of biomarkers across different laboratories.
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Affiliation(s)
- Prasad Devarajan
- Cincinnati Children's Hospital Medical Center, University of Cincinnati, Cincinnati, OH, USA.
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152
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Abstract
The incidence of both acute kidney injury (AKI, previously referred to as acute renal failure) and chronic kidney disease (CKD) is reaching epidemic proportions. In both situations, early intervention can significantly improve the prognosis. However, the paucity of early, predictive, non-invasive biomarkers has impaired our ability to institute potentially effective therapies for these common clinical conditions in a timely manner. The current status of one of the most promising novel biomarkers, namely neutrophil gelatinase-associated lipocalin (NGAL), is presented in this review. The evidence for the role of NGAL measurements in a variety of clinical situations leading to AKI (cardiac surgery, kidney transplantation, contrast nephropathy, haemolytic uraemic syndrome and in the intensive care setting) or to CKD (lupus nephritis, glomerulonephritides, obstruction, dysplasia, polycystic kidney disease, IgA nephropathy) is explored. The emerging utility of standardized clinical platforms for reliable measurement of NGAL in plasma (Triage NGAL Device; Biosite Incorporated) and urine (ARCHITECT analyzer; Abbott Diagnostics) is also discussed. It will be important in future studies to validate the sensitivity and specificity of NGAL concentration measurements in clinical samples from large cohorts and from multiple clinical situations. Such studies will be facilitated by the anticipated widespread availability of standardized commercial tools in the near future.
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Affiliation(s)
- Prasad Devarajan
- Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH 45229-2029, USA.
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153
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Nguyen MT, Devarajan P. Biomarkers for the early detection of acute kidney injury. Pediatr Nephrol 2008; 23:2151-7. [PMID: 17394022 PMCID: PMC6904376 DOI: 10.1007/s00467-007-0470-x] [Citation(s) in RCA: 154] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2007] [Revised: 02/21/2007] [Accepted: 02/22/2007] [Indexed: 12/29/2022]
Abstract
Acute kidney injury (AKI), previously referred to as acute renal failure (ARF), represents a persistent problem in clinical medicine. Despite significant improvements in therapeutics, the mortality and morbidity associated with AKI remain high. A major reason for this is the lack of early markers for AKI, akin to troponins in acute myocardial disease, and hence an unacceptable delay in initiating therapy. Fortunately, the application of innovative technologies such as functional genomics and proteomics to human and animal models of AKI has uncovered several novel genes and gene products that are emerging as biomarkers. The most promising of these are chronicled in this article. These include a plasma panel [neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C] and a urine panel [NGAL, interleukin 18 (IL-18), and kidney injury molecule 1 (KIM)-1]. As they represent sequentially expressed biomarkers, it is likely that the AKI panels will be useful for timing the initial insult and assessing the duration of AKI. Based on the differential expression of the biomarkers, it is also likely that the AKI panels will distinguish between the various types and etiologies of AKI. It will be important in future studies to validate the sensitivity and specificity of these biomarker panels in clinical samples from large cohorts and from multiple clinical situations.
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Affiliation(s)
- Mai T. Nguyen
- Nephrology and Hypertension, MLC 7022, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039 USA
| | - Prasad Devarajan
- Nephrology and Hypertension, MLC 7022, Cincinnati Children’s Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229-3039 USA
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154
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Jones SJ, Florence MM, Ellis IR, Kankova K, Schor SL, Schor AM. Co-expression by keratinocytes of migration stimulating factor (MSF) and a functional inhibitor of its bioactivity (MSFI). Exp Cell Res 2007; 313:4145-57. [DOI: 10.1016/j.yexcr.2007.09.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2007] [Revised: 09/13/2007] [Accepted: 09/15/2007] [Indexed: 11/17/2022]
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155
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Valdebenito M, Müller SI, Hantke K. Special conditions allow binding of the siderophore salmochelin to siderocalin (NGAL-lipocalin). FEMS Microbiol Lett 2007; 277:182-7. [DOI: 10.1111/j.1574-6968.2007.00956.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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156
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Hirsch R, Dent C, Pfriem H, Allen J, Beekman RH, Ma Q, Dastrala S, Bennett M, Mitsnefes M, Devarajan P. NGAL is an early predictive biomarker of contrast-induced nephropathy in children. Pediatr Nephrol 2007; 22:2089-95. [PMID: 17874137 DOI: 10.1007/s00467-007-0601-4] [Citation(s) in RCA: 337] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Revised: 07/24/2007] [Accepted: 07/25/2007] [Indexed: 12/21/2022]
Abstract
We hypothesized that neutrophil gelatinase-associated lipocalin (NGAL) is an early predictive biomarker of contrast-induced nephropathy (CIN). We prospectively enrolled 91 children (age 0-18 years) with congenital heart disease undergoing elective cardiac catheterization and angiography with contrast administration (CC; Ioversol). Serial urine and plasma samples were analyzed in a double-blind fashion by NGAL enzyme-linked immunosorbent assay (ELISA). CIN, defined as a 50% increase in serum creatinine from baseline, was found in 11 subjects (12%), but detection using increase in serum creatinine was only possible 6-24 h after CC. In contrast, significant elevation of NGAL concentrations in urine (135 +/- 32 vs. 11.6 +/- 2 ng/ml without CIN, p < 0.001) and plasma (151 +/- 34 vs. 36 +/- 4 without CIN, p < 0.001) were noted within 2 h after CC in those subjects. Using a cutoff value of 100 ng/ml, sensitivity, specificity, and area under the receiver-operating characteristic (ROC) curve for prediction of CIN were excellent for the 2-h urine NGAL (73%, 100%, and 0.92, respectively) and 2-h plasma NGAL (73%, 100%, and 0.91, respectively). By multivariate analysis, the 2-h NGAL concentrations in the urine (R (2) = 0.52, p < 0.0001) and plasma (R (2) = 0.72, p < 0.0001) were found to be powerful independent predictors of CIN. Patient demographics and contrast volume were not predictive of CIN.
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Affiliation(s)
- Russel Hirsch
- Division of Cardiology, Cincinnati Children's Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH, USA
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157
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Abstract
High-affinity iron acquisition is mediated by siderophore-dependent pathways in the majority of pathogenic and nonpathogenic bacteria and fungi. Considerable progress has been made in characterizing and understanding mechanisms of siderophore synthesis, secretion, iron scavenging, and siderophore-delivered iron uptake and its release. The regulation of siderophore pathways reveals multilayer networks at the transcriptional and posttranscriptional levels. Due to the key role of many siderophores during virulence, coevolution led to sophisticated strategies of siderophore neutralization by mammals and (re)utilization by bacterial pathogens. Surprisingly, hosts also developed essential siderophore-based iron delivery and cell conversion pathways, which are of interest for diagnostic and therapeutic studies. In the last decades, natural and synthetic compounds have gained attention as potential therapeutics for iron-dependent treatment of infections and further diseases. Promising results for pathogen inhibition were obtained with various siderophore-antibiotic conjugates acting as "Trojan horse" toxins and siderophore pathway inhibitors. In this article, general aspects of siderophore-mediated iron acquisition, recent findings regarding iron-related pathogen-host interactions, and current strategies for iron-dependent pathogen control will be reviewed. Further concepts including the inhibition of novel siderophore pathway targets are discussed.
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Affiliation(s)
- Marcus Miethke
- Philipps Universität Marburg, FB Chemie Biochemie, Hans Meerwein Strasse, D-35032 Marburg, Germany
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158
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McEvoy MD, Reeves ST, Reves JG, Spinale FG. Aprotinin in Cardiac Surgery: A Review of Conventional and Novel Mechanisms of Action. Anesth Analg 2007; 105:949-62. [PMID: 17898372 DOI: 10.1213/01.ane.0000281936.04102.9f] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Induction of the coagulation and inflammatory cascades can cause multiorgan dysfunction after cardiopulmonary bypass (CPB). In light of these observations, strategies that can stabilize the coagulation process as well as attenuate the inflammatory response during and after cardiac surgery are important. Aprotinin has effects on hemostasis. In addition, aprotinin may exert multiple biologically relevant effects in the context of cardiac surgery and CPB. For example, it decreases neutrophil and macrophage activation and chemotaxis, attenuates release and activation of proinflammatory cytokines, and reduces oxidative stress. Despite these perceived benefits, the routine use of aprotinin in cardiac surgery with CPB has been called into question. In this review, we examined this controversial drug by discussing the classical and novel pathways in which aprotinin may be operative in the context of cardiac surgery.
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Affiliation(s)
- Matthew D McEvoy
- Department of Anesthesiology and Perioperative Medicine, Medical University of South Carolina, Charleston, South Carolina, USA.
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159
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Bibliography: current world literature. Curr Opin Anaesthesiol 2007; 20:157-63. [PMID: 17413401 DOI: 10.1097/aco.0b013e3280dd8cd1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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160
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Abstract
PURPOSE OF REVIEW Acute renal failure causes considerable morbidity and mortality in critically ill patients. To date, there are few therapies available to clinicians that alter outcome. This review will focus on clinical and basic science research efforts related to the diagnosis, pathophysiology, prevention, and treatment of acute renal failure. RECENT FINDINGS The incidence of acute renal failure may be increasing and the mortality rate continues to be significant. The development of sensitive, predictive biomarkers of acute renal failure may help to diagnose the syndrome earlier and allow for meaningful therapeutic intervention. A number of new therapies are in development for acute renal failure. Many show promise in animal models of acute renal failure but prospective studies in humans are lacking. SUMMARY Despite the present lack of therapies for the treatment and prevention of acute renal failure, there are reasons to be optimistic. Recent research has led to the development of several different strategies that may provide a breakthrough in the treatment of acute renal failure.
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Affiliation(s)
- Dean R Jones
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032-3784, USA
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161
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Mori K, Nakao K. Neutrophil gelatinase-associated lipocalin as the real-time indicator of active kidney damage. Kidney Int 2007; 71:967-70. [PMID: 17342180 DOI: 10.1038/sj.ki.5002165] [Citation(s) in RCA: 290] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Neutrophil gelatinase-associated lipocalin (Ngal, 24p3, SIP24, lipocalin 2, or siderocalin) was originally purified from neutrophils, but with unknown function. Recently, it was identified that Ngal activates nephron formation in the embryonic kidney, is rapidly and massively induced in renal failure and possesses kidney-protective activity. We would like to propose that blood, urine, and kidney Ngal levels are the real-time indicators of active kidney damage, rather than one of many markers of functional nephron number (as Forest Fire Theory). Ngal is a novel iron-carrier protein exerting pleiotropic actions including the upregulation of epithelial marker E-cadherin expression, opening an exciting field in cell biology.
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Affiliation(s)
- K Mori
- Department of Medicine and Clinical Science, Kyoto University Graduate School of Medicine, Kyoto, Japan.
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162
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Schmidt-Ott KM, Mori K, Li JY, Kalandadze A, Cohen DJ, Devarajan P, Barasch J. Dual action of neutrophil gelatinase-associated lipocalin. J Am Soc Nephrol 2007; 18:407-13. [PMID: 17229907 DOI: 10.1681/asn.2006080882] [Citation(s) in RCA: 543] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Neutrophil gelatinase-associated lipocalin (NGAL) is expressed and secreted by immune cells, hepatocytes, and renal tubular cells in various pathologic states. NGAL exerts bacteriostatic effects, which are explained by its ability to capture and deplete siderophores, small iron-binding molecules that are synthesized by certain bacteria as a means of iron acquisition. Consistently, NGAL deficiency in genetically modified mice leads to an increased growth of bacteria. However, growing evidence suggests effects of the protein beyond fighting microorganisms. NGAL acts as a growth and differentiation factor in multiple cell types, including developing and mature renal epithelia, and some of this activity is enhanced in the presence of siderophore:iron complexes. This has led to the hypothesis that eukaryotes might synthesize siderophore-like molecules that bind NGAL. Accordingly, NGAL-mediated iron shuttling between the extracellular and intracellular spaces may explain some of the biologic activities of the protein. Interest in NGAL has been sparked by the observation that NGAL is massively upregulated after renal tubular injury and may participate in limiting kidney damage. This review summarizes the current knowledge about the dual effects of NGAL as a siderophore:iron-binding protein and as a growth factor and examines the role of these effects in renal injury.
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Affiliation(s)
- Kai M Schmidt-Ott
- Department of Medicine, Columbia University College of Physicians and Surgeons, 630 West 168th Street, New York, NY 10032, USA
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