101
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Ham A, Rabadi M, Kim M, Brown KM, Ma Z, D'Agati V, Lee HT. Peptidyl arginine deiminase-4 activation exacerbates kidney ischemia-reperfusion injury. Am J Physiol Renal Physiol 2014; 307:F1052-62. [PMID: 25164081 DOI: 10.1152/ajprenal.00243.2014] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Peptidyl arginine deiminase (PAD)4 is a nuclear enzyme that catalyzes the posttranslational conversion of arginine residues to citrulline. Posttranslational protein citrullination has been implicated in several inflammatory autoimmune diseases, including rheumatoid arthritis, colitis, and multiple sclerosis. Here, we tested the hypothesis that PAD4 contributes to ischemic acute kidney injury (AKI) by exacerbating the inflammatory response after renal ischemia-reperfusion (I/R). Renal I/R injury in mice increased PAD4 activity as well as PAD4 expression in the mouse kidney. After 30 min of renal I/R, vehicle-treated mice developed severe AKI with large increases in plasma creatinine. In contrast, mice pretreated with PAD4 inhibitors (2-chloroamidine or streptonigrin) had significantly reduced renal I/R injury. Further supporting a critical role for PAD4 in generating ischemic AKI, mice pretreated with recombinant human PAD4 (rPAD4) protein and subjected to mild (20 min) renal I/R developed exacerbated ischemic AKI. Consistent with the hypothesis that PAD4 regulates renal tubular inflammation after I/R, mice treated with a PAD4 inhibitor had significantly reduced renal neutrophil chemotactic cytokine (macrophage inflammatory protein-2 and keratinocyte-derived cytokine) expression and had decreased neutrophil infiltration. Furthermore, mice treated with rPAD4 had significantly increased renal tubular macrophage inflammatory protein-2 and keratinocyte-derived cytokine expression as well as increased neutrophil infiltration and necrosis. Finally, cultured mouse kidney proximal tubules treated with rPAD4 had significantly increased proinflammatory chemokine expression compared with vehicle-treated cells. Taken together, our results suggest that PAD4 plays a critical role in renal I/R injury by increasing renal tubular inflammatory responses and neutrophil infiltration after renal I/R.
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Affiliation(s)
- Ahrom Ham
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
| | - May Rabadi
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
| | - Mihwa Kim
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
| | - Kevin M Brown
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
| | - Zhe Ma
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
| | - Vivette D'Agati
- Department of Pathology, College of Physicians and Surgeons of Columbia University, New York, New York
| | - H Thomas Lee
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, New York; and
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102
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Alge JL, Arthur JM. Biomarkers of AKI: a review of mechanistic relevance and potential therapeutic implications. Clin J Am Soc Nephrol 2014; 10:147-55. [PMID: 25092601 DOI: 10.2215/cjn.12191213] [Citation(s) in RCA: 210] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
AKI is a common clinical condition associated with a number of adverse outcomes. More timely diagnosis would allow for earlier intervention and could improve patient outcomes. The goal of early identification of AKI has been the primary impetus for AKI biomarker research, and has led to the discovery of numerous novel biomarkers. However, in addition to facilitating more timely intervention, AKI biomarkers can provide valuable insight into the molecular mechanisms of this complex and heterogeneous disease. Furthermore, AKI biomarkers could also function as molecular phenotyping tools that could be used to direct clinical intervention. This review highlights the major studies that have characterized the diagnostic and prognostic predictive power of these biomarkers. The mechanistic relevance of neutrophil gelatinase-associated lipocalin, kidney injury molecule 1, IL-18, liver-type fatty acid-binding protein, angiotensinogen, tissue inhibitor of metalloproteinase-2, and IGF-binding protein 7 to the pathogenesis and pathobiology of AKI is discussed, putting these biomarkers in the context of the progressive phases of AKI. A biomarker-integrated model of AKI is proposed, which summarizes the current state of knowledge regarding the roles of these biomarkers and the molecular and cellular biology of AKI.
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Affiliation(s)
- Joseph L Alge
- Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina; and
| | - John M Arthur
- Division of Nephrology, Medical University of South Carolina, Charleston, South Carolina; and Medical Service, Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
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103
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Zuk A, Gershenovich M, Ivanova Y, MacFarland RT, Fricker SP, Ledbetter S. CXCR₄antagonism as a therapeutic approach to prevent acute kidney injury. Am J Physiol Renal Physiol 2014; 307:F783-97. [PMID: 25080523 DOI: 10.1152/ajprenal.00685.2013] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined whether antagonism of the CXCR₄receptor ameliorates the loss of renal function following ischemia-reperfusion. CXCR₄is ubiquitously expressed on leukocytes, known mediators of renal injury, and on bone marrow hematopoietic stem cells (HSCs). Plerixafor (AMD3100, Mozobil) is a small-molecule CXCR₄antagonist that mobilizes HSCs into the peripheral blood and also modulates the immune response in in vivo rodent models of asthma and rheumatoid arthritis. Treatment with plerixafor before and after ischemic clamping ameliorated kidney injury in a rat model of bilateral renal ischemia-reperfusion. Serum creatinine and blood urea nitrogen were significantly reduced 24 h after reperfusion, as were tissue injury and cell death. Plerixafor prevented the renal increase in the proinflammatory chemokines CXCL1 and CXCL5 and the cytokine IL-6. Flow cytometry of kidney homogenates confirmed the presence of significantly fewer leukocytes with plerixafor treatment; additionally, myeloperoxidase activity was reduced. AMD3465, a monocyclam analog of plerixafor, was similarly renoprotective. Four weeks postreperfusion, long-term effects included diminished fibrosis, inflammation, and ongoing renal injury. The mechanism by which CXCR₄inhibition ameliorates AKI is due to modulation of leukocyte infiltration and expression of proinflammatory chemokines/cytokines, rather than a HSC-mediated effect. The data suggest that CXCR₄antagonism with plerixafor may be a potential option to prevent AKI.
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Affiliation(s)
- A Zuk
- Tissue Protection and Repair Unit, Renal Science, Genzyme R&D Center, Framingham, Massachusetts;
| | - M Gershenovich
- Tissue Protection and Repair Unit, Renal Science, Genzyme R&D Center, Framingham, Massachusetts
| | - Y Ivanova
- Tissue Protection and Repair Unit, Renal Science, Genzyme R&D Center, Framingham, Massachusetts
| | - R T MacFarland
- Pharmacology and Preclinical Development, Genzyme R&D Center, Framingham, Massachusetts; and
| | - S P Fricker
- Immune-Mediated Disease Research, Genzyme R&D Center, Framingham, Massachusetts
| | - S Ledbetter
- Tissue Protection and Repair Unit, Renal Science, Genzyme R&D Center, Framingham, Massachusetts
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104
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Bayram M, Ezelsoy M, Usta E, Oral K, Saraçoğlu A, Bayramoğlu Z, Yıldırım Ö. Rapid Detection of Acute Kidney Injury by Urinary Neutrophil Gelatinase-Associated Lipocalin in Patients Undergoing Cardiopulmonary Bypass. Turk J Anaesthesiol Reanim 2014; 42:239-44. [PMID: 27366429 DOI: 10.5152/tjar.2014.65668] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 11/25/2013] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVE Acute kidney injury (AKI) is common following cardiopulmonary bypass (CPB). The aim of this study is to determine the accuracy of urinary neutrophil gelatinase-associated lipocalin (NGAL) levels following cardiac surgery to establish the severity of renal impairment as compared to serum creatinine levels. METHODS A total number of 28 patients undergoing elective cardiopulmonary bypass were included. Diagnostic criteria of AKI was established in case of a percentage increase in serum creatinine concentration of >50%. Serum creatinine levels were recorded in the preoperative period before induction and in the postoperative period at 24, 48, and 72 hours. Urinary NGAL measurement was performed before induction and in the 4(th) postoperative hour. The duration of CPB surgery, hospital stay, and cross-clamp time were recorded. RESULTS Based on AKI criteria, subjects were grouped as AKI (n=11) and no AKI (n=19). Postoperative urinary NGAL levels were significantly higher in the group with AKI (11.8 ng mL(-1) vs. 104.0 ng mL(-1), p=0.003). In the AKI group, CPB time bypass (111.9 min vs. 82.7 min) and cross-clamp time (76.9 min vs. 59.1 min) were significantly higher. A cut-off of 25.5 ng mL(-1) yielded a sensitivity of 81.82% and a specificity of 94.12% at the postoperative 4(th) hour with an AUC of 0.947 for predication of AKI. CONCLUSION Urine NGAL rose significantly much earlier as compared to serum creatinine levels in the early postoperative period. Although larger case series are needed, we are of the opinion that urinary NGAL measurements may be used as an early clinical marker of AKI following CPB.
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Affiliation(s)
- Muhammed Bayram
- Department of Cardiovascular Surgery, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Mehmet Ezelsoy
- Department of Cardiovascular Surgery, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Emrah Usta
- Department of Cardiology, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Kerem Oral
- Department of Cardiovascular Surgery, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Ayten Saraçoğlu
- Department of Anaesthesiology, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Zehra Bayramoğlu
- Department of Cardiovascular Surgery, Bilim University Faculty of Medicine, İstanbul, Turkey
| | - Özgür Yıldırım
- Department of Cardiovascular Surgery, Bilim University Faculty of Medicine, İstanbul, Turkey
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105
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Walther CP, Podoll AS, Finkel KW. Summary of clinical practice guidelines for acute kidney injury. Hosp Pract (1995) 2014; 42:7-14. [PMID: 24566591 DOI: 10.3810/hp.2014.02.1086] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Clinical practice guidelines are intended to standardize the diagnosis and treatment of diseases in order to improve both patient outcomes and resource utilization, using evidence-based criteria. As recently as a decade ago, there was no agreed upon definition of acute kidney injury (AKI), making it difficult to conduct proper clinical studies on the epidemiology and treatment of the disorder. Following the advent of the Risk, Injury, Failure, Loss, and End-stage (RIFLE) criteria for defining AKI, several guidelines for the diagnosis and management of AKI have been developed. In our review, we present a narrative description and comparison of the major published guidelines. Overall, there has been significant agreement among the various guidelines, and each seems well-reasoned and clinically useful. Perhaps the most striking conclusion upon review of the various guidelines is the limited scope of knowledge about optimal management of patients with AKI.
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Affiliation(s)
- Carl P Walther
- University of Texas Health Science Center at Houston, Department of Medicine, Division of Renal Diseases and Hypertension, Houston, TX
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106
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Affiliation(s)
- Paul M Palevsky
- Renal Section, VA Pittsburgh Healthcare System, Pittsburgh, Pennsylvania
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107
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Peters E, Heemskerk S, Masereeuw R, Pickkers P. Alkaline phosphatase: a possible treatment for sepsis-associated acute kidney injury in critically ill patients. Am J Kidney Dis 2014; 63:1038-48. [PMID: 24462020 DOI: 10.1053/j.ajkd.2013.11.027] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2013] [Accepted: 11/18/2013] [Indexed: 02/06/2023]
Abstract
Acute kidney injury (AKI) is a common disease in the intensive care unit and accounts for high morbidity and mortality. Sepsis, the predominant cause of AKI in this setting, involves a complex pathogenesis in which renal inflammation and hypoxia are believed to play an important role. A new therapy should be aimed at targeting both these processes, and the enzyme alkaline phosphatase, with its dual mode of action, might be a promising candidate. First, alkaline phosphatase is able to reduce inflammation through dephosphorylation and thereby detoxification of endotoxin (lipopolysaccharide), which is an important mediator of sepsis. Second, adenosine triphosphate, released during cellular stress caused by inflammation and hypoxia, has detrimental effects but can be converted by alkaline phosphatase into adenosine with anti-inflammatory and tissue-protective effects. These postulated beneficial effects of alkaline phosphatase have been confirmed in animal experiments and two phase 2a clinical trials showing that kidney function improved in critically ill patients with sepsis-associated AKI. Because renal inflammation and hypoxia also are observed commonly in AKI induced by other causes, it would be of interest to investigate the therapeutic effect of alkaline phosphatase in these nephropathies as well.
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Affiliation(s)
- Esther Peters
- Department of Intensive Care Medicine, Nijmegen Institute for Infection, Inflammation and Immunity, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pharmacology and Toxicology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Suzanne Heemskerk
- Department of Intensive Care Medicine, Nijmegen Institute for Infection, Inflammation and Immunity, Radboud University Medical Center, Nijmegen, the Netherlands; Department of Pharmacology and Toxicology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Rosalinde Masereeuw
- Department of Pharmacology and Toxicology, Nijmegen Centre for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Peter Pickkers
- Department of Intensive Care Medicine, Nijmegen Institute for Infection, Inflammation and Immunity, Radboud University Medical Center, Nijmegen, the Netherlands.
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108
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Charlton JR, Portilla D, Okusa MD. A basic science view of acute kidney injury biomarkers. Nephrol Dial Transplant 2014; 29:1301-11. [PMID: 24385545 DOI: 10.1093/ndt/gft510] [Citation(s) in RCA: 189] [Impact Index Per Article: 18.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Over the last decade, significant progress has been made in the identification and validation of novel biomarkers as well as refinements in the use of serum creatinine as a marker of kidney function. These advances have taken advantage of laboratory investigations, which have identified these novel molecules that serve important biological functions in the pathogenesis of acute kidney injury (AKI). As we advance and validate these markers for clinical studies in AKI, we recognize that they serve not only to improve our understanding of AKI, but they could also serve as potential targets for the treatment of AKI. This review will underscore the biological basis of specific biomarkers that will contribute to the advancement in the treatment and outcomes of AKI.
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Affiliation(s)
- Jennifer R Charlton
- Department of Pediatrics, University of Virginia Health System, Charlottesville, VA, USA Division of Nephrology, University of Virginia Health System, Charlottesville, VA, USA
| | - Didier Portilla
- Department of Medicine, University of Arkansas for Medical Sciences, Little Rock, AR, USA
| | - Mark D Okusa
- Division of Nephrology, University of Virginia Health System, Charlottesville, VA, USA Department of Medicine, University of Virginia Health System, Charlottesville, VA, USA
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109
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DiRocco DP, Bisi J, Roberts P, Strum J, Wong KK, Sharpless N, Humphreys BD. CDK4/6 inhibition induces epithelial cell cycle arrest and ameliorates acute kidney injury. Am J Physiol Renal Physiol 2013; 306:F379-88. [PMID: 24338822 DOI: 10.1152/ajprenal.00475.2013] [Citation(s) in RCA: 82] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Acute kidney injury (AKI) is common and urgently requires new preventative therapies. Expression of a cyclin-dependent kinase (CDK) inhibitor transgene protects against AKI, suggesting that manipulating the tubular epithelial cell cycle may be a viable therapeutic strategy. Broad spectrum small molecule CDK inhibitors are protective in some kidney injury models, but these have toxicities and epithelial proliferation is eventually required for renal repair. Here, we tested a well-tolerated, novel and specific small molecule inhibitor of CDK4 and CDK6, PD 0332991, to investigate the effects of transient cell cycle inhibition on epithelial survival in vitro and kidney injury in vivo. We report that CDK4/6 inhibition induced G0/G1 cycle arrest in cultured human renal proximal tubule cells (hRPTC) at baseline and after injury. Induction of transient G0/G1 cycle arrest through CDK4/6 inhibition protected hRPTC from DNA damage and caspase 3/7 activation following exposure to the nephrotoxins cisplatin, etoposide, and antimycin A. In vivo, mice treated with PD 0332991 before ischemia-reperfusion injury (IRI) exhibited dramatically reduced epithelial progression through S phase 24 h after IRI. Despite reduced epithelial proliferation, PD 0332991 ameliorated kidney injury as reflected by improved serum creatinine and blood urea nitrogen levels 24 h after injury. Inflammatory markers and macrophage infiltration were significantly decreased in injured kidneys 3 days following IRI. These results indicate that induction of proximal tubule cell cycle arrest with specific CDK4/6 inhibitors, or "pharmacological quiescence," represents a novel strategy to prevent AKI.
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Affiliation(s)
- Derek P DiRocco
- Brigham and Women's Hospital, Harvard Institutes of Medicine, Rm. 550, 4 Blackfan Circle, Boston, MA 02115.
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110
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Nagai K, Doi T. [New era of laboratory testing. Topics: II. Particulars; 3. Laboratory examination for the diagnosis of CKD or AKI]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2013; 102:3125-3132. [PMID: 24605560 DOI: 10.2169/naika.102.3125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Affiliation(s)
- Kojiro Nagai
- Department of Nephrology, The University of Tokushima, Japan
| | - Toshio Doi
- Department of Nephrology, The University of Tokushima, Japan
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111
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Abstract
PURPOSE OF REVIEW Acute kidney injury (AKI) remarkably increases the mortality of critically ill patients treated in ICUs. Recently, several renal biomarkers have been developed for the early detection of AKI. We review the potential of urinary L-type fatty acid-binding protein (L-FABP) as a new renal biomarker for AKI diagnosis in critical care. RECENT FINDINGS In the kidney, L-FABP is expressed in renal proximal tubular epithelial cells and shed into urine rapidly in response to renal insults. By using human L-FABP transgenic mice, we reported that urinary L-FABP can detect AKI sensitively and reflect its severity accurately in animal models of AKI and sepsis. In clinical evaluations, the good performance of urinary L-FABP was demonstrated not only in pediatric postcardiopulmonary bypass surgery AKI and contrast media-induced AKI but also in septic shock patients complicated with AKI. SUMMARY Recent data suggest that urinary L-FABP can contribute to the development of new AKI diagnostic tools in critical care. Combining with other renal markers such as neutrophil gelatinase-associated lipocalin (NGAL) and kidney injury molecule-1 (KIM-1), optimal threshold determination for distinguishing AKI from chronic renal failure should be explored before translation to the clinical.
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112
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Ham A, Kim M, Kim JY, Brown KM, Fruttiger M, D'Agati VD, Lee HT. Selective deletion of the endothelial sphingosine-1-phosphate 1 receptor exacerbates kidney ischemia-reperfusion injury. Kidney Int 2013; 85:807-23. [PMID: 24025642 PMCID: PMC3952061 DOI: 10.1038/ki.2013.345] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2013] [Revised: 07/08/2013] [Accepted: 07/12/2013] [Indexed: 12/26/2022]
Abstract
The role for the endothelial sphingosine-1-phosphate 1 receptor (S1P1R) in acute kidney injury (AKI) remains unclear as germline endothelial S1P1R deletion is embryonically lethal. Here, we generated conditional endothelial S1P1R deficiency by crossing mice with floxed S1P1R with mice expressing a tamoxifen-inducible form of Cre recombinase under the transcriptional control of the platelet-derived growth factor-β gene. Mice with tamoxifen-induced deletion of endothelial S1P1R had increased renal tubular necrosis, inflammation, impaired vascular permeability as well as exacerbated renal tubular apoptosis after ischemic AKI compared to tamoxifen-treated wild type mice. Moreover, endothelial S1P1R deletion resulted in increased hepatic injury after ischemic AKI. As a potential mechanism for exacerbated renal injury, conditional endothelial S1P1R null mice had markedly reduced endothelial HSP27 expression compared to wild type mice. Cultured glomerular endothelial cells treated with a specific S1P1R antagonist (W146) for 3 days also showed reduced HSP27 expression compared to vehicle treated cells. Finally, mice treated with W146 for 3 days also showed reduced endothelial HSP27 expression as well as exacerbated renal and hepatic injury after ischemic AKI. Thus, our studies demonstrate a protective role for endothelial S1P1R against ischemic AKI most likely by regulating endothelial barrier integrity and endothelial HSP27 expression.
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Affiliation(s)
- Ahrom Ham
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York, USA
| | - Mihwa Kim
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York, USA
| | - Joo Yun Kim
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York, USA
| | - Kevin M Brown
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York, USA
| | - Marcus Fruttiger
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Vivette D D'Agati
- Department of Pathology, College of Physicians and Surgeons of Columbia University, New York, New York, USA
| | - H Thomas Lee
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons of Columbia University, Columbia University, New York, New York, USA
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113
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Çelik T, Altekin E, İşgüder R, Kenesari Y, Duman M, Arslan N. Evaluation of neutrophil gelatinase-associated lipocalin in pediatric patients with acute rotavirus gastroenteritis and dehydration. Ital J Pediatr 2013; 39:52. [PMID: 24004459 PMCID: PMC3844336 DOI: 10.1186/1824-7288-39-52] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2013] [Accepted: 08/24/2013] [Indexed: 12/05/2022] Open
Abstract
Background Dehydration caused by acute rotavirus gastroenteritis is a frequent finding in pediatric patients. The most important treatment modality in these patients is recognising and treating dehydration, electrolyte imbalance and acute kidney injury. Neutrophil gelatinase-asssociated lipocalin (NGAL) is used widely as a biomarker for the diagnosis of acute or chronic renal injury in numerous clinical studies. It is recognized as an early marker of acute renal failure before the elevation of routine biochemical tests such as creatinine. The aim of this study is to investigate the plasma and urine NGAL concentrations in mildly or moderately dehydrated patients with acute rotavirus gastroenteritis. Material and methods A total of 30 patients (13 girls, mean age 62.5 ± 46.2 months) with diarrhea and mild/moderate dehydration and 35 healthy controls (17 girls, mean age 81.1 ± 41.8 months) were enrolled in the study. Plasma and urine NGAL levels of the two groups were compared. Results The mean age, gender and serum creatinine levels of the patients and healthy controls were similar. The mean plasma and urine NGAL levels of the patients were significantly higher than controls (plasma: 118.6 ± 81.2 vs. 66.5 ± 11.3, p = 0.001 and urine: 17.7 ± 17.5 vs. 10.6 ± 7.9, p = 0.035, respectively). Conclusion Mildly or moderately dehydrated children have higher plasma and urine NGAL levels compared to control subjects. Plasma and/or urine NGAL levels can be used for the early prediction of renal impairment in children with mild or moderate dehydration.
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Affiliation(s)
- Tanju Çelik
- Department of Pediatric Emergency, Dr, Behcet Uz Children Hospital, Izmir, Turkey.
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114
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Hamed HM, El-Sherbini SA, Barakat NA, Farid TM, Rasheed EA. Serum cystatin C is a poor biomarker for diagnosing acute kidney injury in critically-ill children. Indian J Crit Care Med 2013; 17:92-8. [PMID: 23983414 PMCID: PMC3752874 DOI: 10.4103/0972-5229.114829] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background: Accurate diagnosis of acute kidney injury (AKI) is problematic especially in critically-ill patients in whom renal function is in an unsteady state. Aim: Our aim was to evaluate the role of serum (S.) cystatin C as an early biomarker of AKI in critically-ill children. Subjects and Methods: S. creatinine and S. cystatin C were measured in 32 critically-ill children who were at risk for developing AKI. AKI was defined by both: Risk,-injury,-failure,-loss, and-endstage renal disease (RIFLE) classification and glomerular filtration rate (GFR) <80 ml/min/1.73 m2. GFR was estimated by both Schwartz formula and S. cystatin C-based equation. Results: S. cystatin C was not statistically higher in AKI patients compared with non-AKI by RIFLE classification (median 1.48 mg/l vs. 1.16 mg/l, P = 0.1) while S. creatinine was significantly higher (median 0.8 mg/dl vs. 0.4 mg/dl, P = 0.001). On estimating GFR by the two equations we found, a lag between rise of S. cystatin C and creatinine denoted by lower GFR by Schwartz formula in four patients, on other hand, six patients had elevated S. cystatin C with low GFR despite normal creatinine and GFR, denoting poor concordance between the two equations and the two markers. The ability of S. creatinine in predicting AKI was superior to S. cystatin with area under the curve (AUC) 0.95 with sensitivity and specificity (100% and 84.6%, respectively) using the RIFLE classification. The same findings were found when using Schwartz formula. Conclusion: S. cystatin C is a poor biomarker for diagnosing AKI in critically-ill children.
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Affiliation(s)
- Hanan M Hamed
- Department of Pediatrics, National Research Centre, Cairo, Egypt
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115
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Wang PR. Mouse adult renal progenitor cells in combination with erythropoietin or suramin--a potential new strategy for the treatment of acute kidney injury. Stem Cell Res Ther 2013; 4:89. [PMID: 23899649 PMCID: PMC3854771 DOI: 10.1186/scrt274] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Experimental evidence has indicated a role of adult renal progenitor cells in kidney regeneration and a protective role of the kidney by erythropoietin (EPO) and suramin in animal models and in humans after acute kidney injury (AKI). Han and colleagues analyzed different therapeutic effects between mouse renal progenitor cells (MRPCs), MRPC/EPO, or MRPC/suramin on the regeneration and protection of renal function after AKI. Their results revealed that MRPCs in combination with EPO or suramin are able to attenuate renal damage and promote renal recovery after ischemia/reperfusion injury in a mouse model. The researchers concluded that the combined approach with MRPCs and EPO or suramin could be a new therapeutic strategy for AKI.
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116
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Chaturvedi S, Yuen DA, Bajwa A, Huang YW, Sokollik C, Huang L, Lam GY, Tole S, Liu GY, Pan J, Chan L, Sokolskyy Y, Puthia M, Godaly G, John R, Wang C, Lee WL, Brumell JH, Okusa MD, Robinson LA. Slit2 prevents neutrophil recruitment and renal ischemia-reperfusion injury. J Am Soc Nephrol 2013; 24:1274-87. [PMID: 23766538 DOI: 10.1681/asn.2012090890] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Neutrophils recruited to the postischemic kidney contribute to the pathogenesis of ischemia-reperfusion injury (IRI), which is the most common cause of renal failure among hospitalized patients. The Slit family of secreted proteins inhibits chemotaxis of leukocytes by preventing activation of Rho-family GTPases, suggesting that members of this family might modulate the recruitment of neutrophils and the resulting IRI. Here, in static and microfluidic shear assays, Slit2 inhibited multiple steps required for the infiltration of neutrophils into tissue. Specifically, Slit2 blocked the capture and firm adhesion of human neutrophils to inflamed vascular endothelial barriers as well as their subsequent transmigration. To examine whether these observations were relevant to renal IRI, we administered Slit2 to mice before bilateral clamping of the renal pedicles. Assessed at 18 hours after reperfusion, Slit2 significantly inhibited renal tubular necrosis, neutrophil and macrophage infiltration, and rise in plasma creatinine. In vitro, Slit2 did not impair the protective functions of neutrophils, including phagocytosis and superoxide production, and did not inhibit neutrophils from killing the extracellular pathogen Staphylococcus aureus. In vivo, administration of Slit2 did not attenuate neutrophil recruitment or bacterial clearance in mice with ascending Escherichia coli urinary tract infections and did not increase the bacterial load in the livers of mice infected with the intracellular pathogen Listeria monocytogenes. Collectively, these results suggest that Slit2 may hold promise as a strategy to combat renal IRI without compromising the protective innate immune response.
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Affiliation(s)
- Swasti Chaturvedi
- Division of Nephrology, Hospital for Sick Children, Toronto, Ontario, Canada
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117
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Ali FN, Hassinger A, Price H, Langman CB. Preoperative plasma FGF23 levels predict acute kidney injury in children: results of a pilot study. Pediatr Nephrol 2013; 28:959-62. [PMID: 23314442 DOI: 10.1007/s00467-012-2395-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2012] [Revised: 12/06/2012] [Accepted: 12/07/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND Acute kidney injury (AKI) carries a large burden of morbidity and mortality. Early diagnosis may lead to better strategies of clinical care. Cardiac surgery involving cardiopulmonary bypass is associated with a significant incidence of AKI. The study objective was to determine whether or not preoperative fibroblast growth factor-23 (FGF23) levels differed among pediatric patients who did or did not develop AKI following cardiac surgery. METHODS A nested case-control study was performed. FGF23 levels were measured pre- and post-operatively in 19 children without chronic kidney disease (CKD) who underwent cardiopulmonary bypass. Five patients developed AKI and 14 patients served as controls. RESULTS FGF23 levels in patients who developed AKI following cardiac surgery were elevated above normal levels, both pre-operatively and post-operatively compared with those patients who did not develop AKI. Relative risk of developing AKI when the pre-operative FGF23 level was >86 RU/mL was 2.0 (p = 0.033). Preoperative FGF23 levels correlated with post-operative fluid gain (correlation coefficient 0.607, p = 0.0059). CONCLUSIONS FGF23 may serve as a pre-operative prognostic indicator of the development of AKI following cardiopulmonary bypass surgery in pediatric patients without CKD. Identifying patients more likely to have AKI following surgery provides a means of achieving closer clinical management of AKI and fluid balance.
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Affiliation(s)
- Farah N Ali
- Kidney Diseases, Lurie Children's Hospital, 225 E Chicago Avenue, Box 37, Chicago, IL, USA.
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118
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Singer E, Markó L, Paragas N, Barasch J, Dragun D, Müller DN, Budde K, Schmidt-Ott KM. Neutrophil gelatinase-associated lipocalin: pathophysiology and clinical applications. Acta Physiol (Oxf) 2013; 207:663-72. [PMID: 23375078 DOI: 10.1111/apha.12054] [Citation(s) in RCA: 161] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 11/13/2012] [Accepted: 12/06/2012] [Indexed: 12/22/2022]
Abstract
Neutrophil gelatinase-associated lipocalin (NGAL), a 25 kDa protein produced by injured nephron epithelia, is one of the most promising new markers of renal epithelial injury. In contrast to serum creatinine and urinary output, which are the measures of kidney function, NGAL is specifically induced in the damaged nephron and then released into blood and urine, where it can be readily measured. Careful proof-of-concept studies using defined animal models have uncovered the sources and trafficking of NGAL in acute kidney injury (AKI) and have addressed the contributions of renal and non-renal sources. Clinical studies indicate that NGAL, unlike creatinine, is a marker responsive to tissue stress and nephron injury, but less so to adaptive hemodynamic responses. In certain clinical settings, NGAL is an earlier marker compared with serum creatinine. In addition, clinical studies have shown that NGAL is a powerful predictor of poor clinical outcomes, which can be used to risk stratify patients when combined with serum creatinine. NGAL has important limitations, including its responsiveness in systemic inflammation, which is partially uncoupled from its response to kidney injury and which needs to be considered when interpreting NGAL results clinically. This review covers the biology and pathophysiology of NGAL and summarizes the results of the growing body of clinical studies that have addressed the utility of NGAL in the early diagnosis of AKI, in the distinction of intrinsic AKI and in the prognostic assessment of broad patient populations.
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Affiliation(s)
- E. Singer
- Department of Nephrology; Campus Mitte; Charité - Universitätsmedizin Berlin; Berlin; Germany
| | - L. Markó
- Experimental and Clinical Research Center; a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine; Berlin; Germany
| | - N. Paragas
- Department of Medicine; Columbia University College of Physicians and Surgeons; New York; NY; USA
| | - J. Barasch
- Department of Medicine; Columbia University College of Physicians and Surgeons; New York; NY; USA
| | - D. Dragun
- Department of Nephrology and Intensive Care Medicine Campus Virchow Klinikum; Charité - Universitätsmedizin Berlin; Berlin; Germany
| | - D. N. Müller
- Experimental and Clinical Research Center; a joint cooperation between the Charité Medical Faculty and the Max-Delbrück Center for Molecular Medicine; Berlin; Germany
| | - K. Budde
- Department of Nephrology; Campus Mitte; Charité - Universitätsmedizin Berlin; Berlin; Germany
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119
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Annigeri RA. Urinary biomarkers in acute kidney injury. APOLLO MEDICINE 2013. [DOI: 10.1016/j.apme.2013.02.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Lee HT, Kim JY, Kim M, Wang P, Tang L, Baroni S, D'Agati VD, Desir GV. Renalase protects against ischemic AKI. J Am Soc Nephrol 2013; 24:445-55. [PMID: 23393318 DOI: 10.1681/asn.2012090943] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Elevated levels of plasma catecholamines accompany ischemic AKI, possibly contributing the inflammatory response. Renalase, an amine oxidase secreted by the proximal tubule, degrades circulating catecholamines and reduces myocardial necrosis, suggesting that it may protect against renal ischemia reperfusion injury. Here, mice subjected to renal ischemia reperfusion injury had significantly lower levels of renalase in the plasma and kidney compared with sham-operated mice. Consistent with this, plasma NE levels increased significantly after renal ischemia reperfusion injury. Furthermore, renal tubular inflammation, necrosis, and apoptosis were more severe and plasma catecholamine levels were higher in renalase-deficient mice subjected to renal ischemia reperfusion compared with wild-type mice. Administration of recombinant human renalase reduced plasma catecholamine levels and ameliorated ischemic AKI in wild-type mice. Taken together, these data suggest that renalase protects against ischemic AKI by reducing renal tubular necrosis, apoptosis, and inflammation, and that plasma renalase might be a biomarker for AKI. Recombinant renalase therapy may have potential for the prevention and treatment of AKI.
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Affiliation(s)
- H Thomas Lee
- Department of Anesthesiology, Anesthesiology Research Laboratories, College of Physicians and Surgeons, Columbia University, P&S Box 46 (PH-5), 630 West 168th Street, New York, NY 10032-3784, USA.
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121
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El-Achkar TM, McCracken R, Liu Y, Heitmeier MR, Bourgeois S, Ryerse J, Wu XR. Tamm-Horsfall protein translocates to the basolateral domain of thick ascending limbs, interstitium, and circulation during recovery from acute kidney injury. Am J Physiol Renal Physiol 2013; 304:F1066-75. [PMID: 23389456 DOI: 10.1152/ajprenal.00543.2012] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Tamm-Horsfall protein (THP) is a glycoprotein normally targeted to the apical membrane domain of the kidney's thick ascending limbs (TAL). We previously showed that THP of TAL confers protection to proximal tubules against acute kidney injury (AKI) via a possible cross talk between the two functionally distinct tubular segments. However, the extent, timing, specificity, and functional effects of basolateral translocation of THP during AKI remain unclear. Using an ischemia-reperfusion (IRI) model of murine AKI, we show here that, while THP expression in TAL is downregulated at the peak of injury, it is significantly upregulated 48 h after IRI. Confocal immunofluorescence and immunoelectron microscopy reveal a major redirection of THP during recovery from the apical membrane domain of TAL towards the basolateral domain, interstitium, and basal compartment of S3 segments. This corresponds with increased THP in the serum but not in the urine. The overall epithelial polarity of TAL cells does not change, as evidenced by correct apical targeting of Na(+)-K(+)-2Cl cotransporter (NKCC2) and basolateral targeting of Na(+)-K(+)-ATPase. Compared with the wild-type, THP(-/-) mice show a significantly delayed renal recovery after IRI, due possibly to reduced suppression by THP of proinflammatory cytokines and chemokines such as monocyte chemoattractant protein-1 during recovery. Taken together, our data suggest that THP redistribution in the TAL after AKI is a protein-specific event and its increased interstitial presence negatively regulates the evolving inflammatory signaling in neighboring proximal tubules, thereby enhancing kidney recovery. The increase of serum THP may be used as a prognostic biomarker for recovery from AKI.
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Affiliation(s)
- Tarek M El-Achkar
- Division of Nephrology, Indiana University and Roudebush Indianapolis Veterans Affairs Medical Center, Indianapolis, IN 46202, USA.
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122
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Endre ZH, Pickering JW. Acute kidney injury clinical trial design: old problems, new strategies. Pediatr Nephrol 2013; 28:207-17. [PMID: 22639043 DOI: 10.1007/s00467-012-2171-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/26/2012] [Accepted: 03/27/2012] [Indexed: 01/11/2023]
Abstract
Apart from supportive dialysis there are no universally accepted interventions in acute kidney injury (AKI). We have summarized the outcomes of all published randomized, placebo-controlled studies of non-dialysis treatment of AKI. Forty-nine trials were identified, only one of which was in a paediatric population. Sixteen trials had positive outcomes; these trials are not comparable in terms of methodology used or outcomes assessed, and they share many of the problems of the negative trials. We discuss the flaws in clinical trial design that have contributed to poor or uncertain outcomes and propose minimum requirements for future trials. In particular, future trials should incorporate biomarkers specific to the etiology of the AKI, and treatment should match the phase of injury.
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Affiliation(s)
- Zoltán H Endre
- Christchurch Kidney Research Group, Department of Medicine, University of Otago, Christchurch, New Zealand.
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123
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Abstract
BACKGROUND Acute kidney injury (AKI), which is common in hospitalised patients, is associated with significant morbidity and mortality. Despite recent advances in treatment, AKI outcomes have not changed substantially during the past four decades, and incidence is increasing. There is an urgent need to explore novel therapeutic agents and revisit some older drugs to review their roles in the management of AKI. Although thyroid hormone therapy has shown promise in experimental animal studies, clinical efficacy and safety have not been systematically assessed for the management of people with AKI. OBJECTIVES To evaluate the benefits and harms of thyroid hormones for the treatment of hospitalised adults with AKI of any aetiology. SEARCH METHODS We searched the Cochrane Renal Group's Specialised Register, CENTRAL, MEDLINE, and EMBASE. We also checked the reference lists of retrieved studies and articles.Date of search: November 2012 SELECTION CRITERIA Randomised controlled trials (RCTs) and quasi-RCTs (in which allocation to treatment was obtained by alternation, use of alternate medical records, date of birth or other predictable methods) that compared any dose or form of thyroid hormone therapy alone or in combination with other agents compared with placebo or supplemental treatment (such as furosemide, dopamine, or atrial natriuretic peptide) in adult AKI patients. DATA COLLECTION AND ANALYSIS Two authors independently assessed study quality and extracted data. The quality of included studies was assessed using the Cochrane Collaboration's risk of bias assessment tool. For dichotomous outcomes (death, need for renal replacement therapy (RRT), progression to end-stage kidney disease (ESKD)), we planned to express results as risk ratios (RR) with 95% confidence intervals (CI). Where continuous scales of measurement were used to assess the effects of treatment (length of hospital stay, durations of AKI and RRT), we planned to use the mean difference (MD). MAIN RESULTS Two studies, enrolling 97 participants, met our inclusion criteria. The studies differed significantly in terms of study populations, natural history of AKI (multifactorial AKI in patients with native kidneys versus delayed graft function associated with acute tubular necrosis in transplant recipients), and study interventions; hence, data were not meta-analysed. One study reported a significant increase in the risk of all-cause mortality associated with thyroid hormone interventions compared with placebo (59 participants, RR 3.32, 95% CI 1.21 to 9.12); no deaths were reported in the other study. Both studies reported no significant difference in the need for RRT associated with thyroid hormone therapy when compared to placebo. Neither study reported incidence of progression to ESKD. There was a significantly longer duration of AKI (MD 2.00 days, 95% CI 0.18 to 3.82) and RRT (5.00 days, 95% CI 2.05 to 7.95) associated with thyroid hormone therapy compared with placebo in one study; no differences in durations of AKI (MD 2.00 days, 95% CI -3.53 to 7.53) and RRT (MD 2.00 days, 95% CI -2.36 to 6.36) were noted in the other study. One study reported similar lengths of stay in the intensive care unit and hospital in both intervention and control arms (MD -0.20 days, 95% CI -8.17 to 7.77); the other did not report this outcome. No adverse events were noted to be associated with thyroid hormone therapy in either study. Adequate data were not available to assess changes in kidney function or numbers of RRT sessions. Both included studies were small and methodological quality was suboptimal. AUTHORS' CONCLUSIONS We found a paucity of large, high quality studies to inform analysis of thyroid hormone interventions for the treatment of people with AKI. Current evidence suggested that thyroid hormone therapy may be associated with worse outcomes for patients with established AKI; therefore, its use for these patients should be avoided. The role of thyroid hormone therapy in preventing AKI has not been adequately investigated and may be considered in future clinical studies.
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Affiliation(s)
- Sagar U Nigwekar
- Brigham and Women’s Hospital, Massachusetts General Hospital, Harvard Medical School, Boston, MA,
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124
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Si J, Ge Y, Zhuang S, Wang LJ, Chen S, Gong R. Adrenocorticotropic hormone ameliorates acute kidney injury by steroidogenic-dependent and -independent mechanisms. Kidney Int 2013; 83:635-46. [PMID: 23325074 PMCID: PMC3612362 DOI: 10.1038/ki.2012.447] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Adrenocorticotropic hormone (ACTH) has a renoprotective effect in chronic kidney disease; however, its effect on acute kidney injury (AKI) remains unknown. In a rat model of tumor necrosis factor (TNF)–induced AKI, we found that ACTH gel prevented kidney injury, corrected acute renal dysfunction, and improved survival. Morphologically, ACTH gel ameliorated TNF-induced acute tubular necrosis, associated with a reduction in tubular apoptosis. While the steroidogenic response to ACTH gel plateaued, the kidney-protective effect continued to increase at even higher doses, suggesting steroid-independent mechanisms. Of note, ACTH also acts as a key agonist of the melanocortin system, with its cognate melanocortin 1 receptor (MC1R) abundantly expressed in renal tubules. In TNF-injured tubular epithelial cells in vitro, ACTH reinstated cellular viability and eliminated apoptosis. This beneficial effect was blunted in MC1R-silenced cells, suggesting that this receptor mediates the anti-apoptotic signaling of ACTH. Moreover, ACTH gel protected mice against cecal ligation puncture–induced septic AKI better than α-melanocyte-stimulating hormone: a protein equal in biological activity to ACTH except for steroidogenesis. Thus, ACTH has additive renoprotective actions achieved by both steroid-dependent mechanisms and MC1R-directed anti-apoptosis. ACTH may represent a novel therapeutic strategy to prevent or treat AKI.
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Affiliation(s)
- Jin Si
- Division of Kidney Disease and Hypertension, Department of Medicine, Rhode Island Hospital, Brown Medical School, Providence, Rhode Island 02903, USA
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125
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Fujikura T, Togawa A, Sun Y, Iwakura T, Yasuda H, Fujigaki Y. Dephosphorylated Ser985 of c-Met is associated with acquired resistance to rechallenge injury in rats that had recovered from uranyl acetate-induced subclinical renal damage. Clin Exp Nephrol 2012; 17:504-14. [PMID: 23250664 DOI: 10.1007/s10157-012-0757-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
BACKGROUND We previously reported that rats that had recovered from mild proximal tubule (PT) injury induced by a sub-toxic dose of uranyl acetate (UA) showed partial resistance to a subsequent nephrotoxic dose of UA in association with reduced renal dysfunction and accelerated PT proliferation. We demonstrated that this resistance may involve hepatocyte growth factor (HGF)/c-Met signaling. Here, we examined whether primary cultured tubular cells derived from this model had acquired sensitivity to HGF. METHODS Tubular cells were isolated by collagenase digestion from rat kidneys after recovery from UA-induced mild PT injury and were cultured for 48 h. Their survival and proliferation were examined using the MTS assay/5-bromo-2'-deoxyuridine labeling or MTS assay, respectively, and their migration was assayed using wound-healing and cell scattering assays, with/without HGF. HGF/c-Met signaling was assayed using phospho-specific antibodies. RESULTS HGF-stimulated cultured tubular cells from UA-treated rats showed better survival after UA exposure and higher proliferation and migration than cells from vehicle-treated rats. Furthermore, HGF induced higher phosphorylation of c-Met (Tyr1234/1235) and of its major downstream signals (AKT and extracellular signal-regulated kinase 1/2) with maintained dephosphorylation of Ser985 as a negative regulator of HGF/c-Met signaling in the tubular cells of UA-treated rats compared to those of vehicle-treated rats. Immunohistochemically, dephosphorylated Ser985 was confirmed in PT cells in vivo. CONCLUSIONS These results suggest that elevated sensitivity to HGF, via dephosphorylated Ser985 of c-Met of tubular cells that had recovered from mild tubular injury, may be associated with cytoprotection, accelerated proliferation and migration.
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Affiliation(s)
- Tomoyuki Fujikura
- Internal Medicine 1, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashiku, Hamamatsu, Shizuoka, 431-3192, Japan
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126
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Secreted factors from bone marrow stromal cells upregulate IL-10 and reverse acute kidney injury. Stem Cells Int 2012; 2012:392050. [PMID: 23319959 PMCID: PMC3539665 DOI: 10.1155/2012/392050] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2012] [Accepted: 11/02/2012] [Indexed: 12/26/2022] Open
Abstract
Acute kidney injury is a devastating syndrome that afflicts over 2,000,000 people in the US per year, with an associated mortality of greater than 70% in severe cases. Unfortunately, standard-of-care treatments are not sufficient for modifying the course of disease. Many groups have explored the use of bone marrow stromal cells (BMSCs) for the treatment of AKI because BMSCs have been shown to possess unique anti-inflammatory, cytoprotective, and regenerative properties in vitro and in vivo. It is yet unresolved whether the primary mechanisms controlling BMSC therapy in AKI depend on direct cell infusion, or whether BMSC-secreted factors alone are sufficient for mitigating the injury. Here we show that BMSC-secreted factors are capable of providing a survival benefit to rats subjected to cisplatin-induced AKI. We observed that when BMSC-conditioned medium (BMSC-CM) is administered intravenously, it prevents tubular apoptosis and necrosis and ameliorates AKI. In addition, we observed that BMSC-CM causes IL-10 upregulation in treated animals, which is important to animal survival and protection of the kidney. In all, these results demonstrate that BMSC-secreted factors are capable of providing support without cell transplantation, and the IL-10 increase seen in BMSC-CM-treated animals correlates with attenuation of severe AKI.
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127
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Prevention of postoperative acute kidney injury: one step closer. Am J Med 2012; 125:1153-4. [PMID: 23084972 DOI: 10.1016/j.amjmed.2012.07.021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 07/13/2012] [Accepted: 07/13/2012] [Indexed: 11/22/2022]
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128
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Li L, Huang L, Ye H, Song SP, Bajwa A, Lee SJ, Moser EK, Jaworska K, Kinsey GR, Day YJ, Linden J, Lobo PI, Rosin DL, Okusa MD. Dendritic cells tolerized with adenosine A₂AR agonist attenuate acute kidney injury. J Clin Invest 2012; 122:3931-42. [PMID: 23093781 DOI: 10.1172/jci63170] [Citation(s) in RCA: 125] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 08/16/2012] [Indexed: 12/13/2022] Open
Abstract
DC-mediated NKT cell activation is critical in initiating the immune response following kidney ischemia/reperfusion injury (IRI), which mimics human acute kidney injury (AKI). Adenosine is an important antiinflammatory molecule in tissue inflammation, and adenosine 2A receptor (A₂AR) agonists protect kidneys from IRI through their actions on leukocytes. In this study, we showed that mice with A₂AR-deficient DCs are more susceptible to kidney IRI and are not protected from injury by A₂AR agonists. In addition, administration of DCs treated ex vivo with an A₂AR agonist protected the kidneys of WT mice from IRI by suppressing NKT production of IFN-γ and by regulating DC costimulatory molecules that are important for NKT cell activation. A₂AR agonists had no effect on DC antigen presentation or on Tregs. We conclude that ex vivo A₂AR-induced tolerized DCs suppress NKT cell activation in vivo and provide a unique and potent cell-based strategy to attenuate organ IRI.
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Affiliation(s)
- Li Li
- Department of Medicine, University of Virginia, Charlottesville, Virginia, USA.
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129
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Tögel FE, Westenfelder C. Kidney protection and regeneration following acute injury: progress through stem cell therapy. Am J Kidney Dis 2012; 60:1012-22. [PMID: 23036928 DOI: 10.1053/j.ajkd.2012.08.034] [Citation(s) in RCA: 100] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2011] [Accepted: 08/13/2012] [Indexed: 01/01/2023]
Abstract
Acute kidney injury (AKI) is a common clinical entity with high morbidity and mortality rates and ever increasing medical costs. A large number of patients who are hospitalized with morbidities such as diabetes, vascular disease, or chronic kidney disease are at high risk to develop AKI due to ischemic and nephrotoxic insults. The pathophysiology of ischemic and toxic forms of AKI is complex and includes tubular and vascular cell damage and inflammation. Given the seriousness of this essentially therapy-resistant complication, treatment beyond supportive measures and renal replacement therapy is urgently needed. Recent stem cell research has shown promising results, and cell therapy-based interventions are advancing into clinical trials. An example is our phase 1 clinical trial (NCT00733876) in which cardiac surgery patients at high risk of postoperative AKI were treated safely with allogeneic mesenchymal stem cells. Together with the introduction of biomarkers for an earlier and specific AKI diagnosis, currently tested stem cell-based therapies are expected to provide an entirely new class of diagnostic and therapeutic tools.
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Affiliation(s)
- Florian E Tögel
- Department of Medicine, Division of Nephrology, Brigham and Women's Hospital, Boston, MA, USA
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130
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Current therapeutic strategies for acute kidney injury. Clin Exp Nephrol 2012; 16:672-8. [DOI: 10.1007/s10157-012-0685-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2012] [Accepted: 08/06/2012] [Indexed: 10/28/2022]
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131
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Lee HT, Park SW, Kim M, Ham A, Anderson LJ, Brown KM, D'Agati VD, Cox GN. Interleukin-11 protects against renal ischemia and reperfusion injury. Am J Physiol Renal Physiol 2012; 303:F1216-24. [PMID: 22859402 DOI: 10.1152/ajprenal.00220.2012] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal ischemia reperfusion (IR) injury causes renal tubular necrosis, apoptosis, and inflammation leading to acute and chronic kidney dysfunction. IL-11 is a multifunctional hematopoietic cytokine clinically approved to treat chemotherapy-induced thrombocytopenia. Recent studies suggest that IL-11 also has potent antiapoptotic and antinecrotic properties. In this study, we tested the hypothesis that exogenous IL-11 protects against renal IR injury and determined the mechanisms involved in renal protection. Pretreatment with human recombinant IL-11 (HR IL-11) or with long-acting site-specific polyethylene glycol (PEG)-conjugated human IL-11 analog (PEGylated IL-11) produced partial but significant protection against renal IR injury in mice. In addition, HR IL-11 or PEGylated IL-11 given 30-60 min after IR also provided renal protection in mice. Significant reductions in renal tubular necrosis and neutrophil infiltration as well as tubular apoptosis were observed in mice treated with HR IL-11 or PEGylated IL-11. Furthermore, HR IL-11 or PEGylated IL-11 decreased both necrosis and apoptosis in human proximal tubule (HK-2) cells in culture. Mechanistically, IL-11 increased nuclear translocation of hypoxia-inducible factor-1α (HIF-1α) and induced sphingosine kinase-1 (SK1) expression and activity in HK-2 cells. Moreover, selective HIF-1α inhibitors blocked IL-11-mediated induction of SK1 in HK-2 cells. Finally, HR IL-11 or PEGylated IL-11 failed to protect against renal IR injury in SK1-deficient mice. Together, our data show powerful renal protective effects of exogenous IL-11 against IR injury by reducing necrosis, inflammation, and apoptosis through induction of SK1 via HIF-1α.
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Affiliation(s)
- H Thomas Lee
- Department of Anesthesiology, Anesthesiology Research Laboratories, Columbia University, West 168th St., New York, NY 10032-3784, USA.
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Askenazi DJ, Koralkar R, Hundley HE, Montesanti A, Parwar P, Sonjara S, Ambalavanan N. Urine biomarkers predict acute kidney injury in newborns. J Pediatr 2012; 161:270-5.e1. [PMID: 22424940 PMCID: PMC3598122 DOI: 10.1016/j.jpeds.2012.02.007] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/09/2011] [Revised: 01/10/2012] [Accepted: 02/06/2012] [Indexed: 12/31/2022]
Abstract
OBJECTIVE To identify urine biomarkers predictive of acute kidney injury (AKI) in infants admitted to level 2 and 3 neonatal intensive care units with birth weight >2000 g and 5-minute Apgar score ≤ 7. STUDY DESIGN A nested case-control study was performed comparing 8 candidate urine AKI biomarkers in infants with AKI (defined as a rise in serum creatinine of at least 0.3 mg/dL or a serum creatinine elevation ≥ 1.7 mg/dL persisting for 3 days) and 24 infants from the described cohort without AKI. Urine was analyzed for neutrophil gelatinase-associated lipocalin, osteopontin, cystatin C, albumin, β(2) microglobulin, epithelial growth factor, uromodulin (UMOD), and kidney injury molecule 1. RESULTS Compared with the infants without AKI, those with AKI had higher levels of urine cystatin C (1123 pg/mL [95% CI, 272-4635 pg/mL] vs 90 pg/mL [95% CI, 39-205 pg/mL]; P < .004; area under the receiver operating characteristic curve [AUC] = 0.82), lower levels of UMOD (11.0 pg/mL [95% CI, 5.7-21.4 pg/mL] vs 26.2 pg/mL [95% CI, 17.4-39.4 pg/mL]; P < .03; AUC = 0.77), and lower levels of epithelial growth factor (6.7 pg/mL [95% CI, 4.0-11.3 pg/mL] vs 17.4 pg/mL [95% CI, 12.7-23.8 pg/mL; P = .003; AUC = 0.82). Although the differences were not statistically significant, levels of urine neutrophil-associated gelatinase lipocalin, kidney injury molecule 1, and osteopontin trended higher in infants with AKI. CONCLUSION Urinary biomarkers can predict AKI in neonates admitted to level 2 and 3 neonatal intensive care units.
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Affiliation(s)
- David J. Askenazi
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Rajesh Koralkar
- Department of Public Health, University of Alabama at Birmingham, Birmingham, AL
| | - Hayden E. Hundley
- Department of Medicine, University of South Alabama College of Medicine, Mobile, AL
| | - Angela Montesanti
- Center for Healthy Development, Georgia State University Institute of Public Health, Atlanta, GA
| | - Pushkar Parwar
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, AL
| | - Srdjan Sonjara
- O’Brien Center for AKI Research, University of California at San Diego, La Jolla, CA
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Abstract
Acute kidney injury (AKI) is a syndrome with a multitude of causes and is associated with high mortality and a permanent loss of renal function. Our current understanding of the most common causes of AKI is limited, and thus a silver bullet therapy remains elusive. A change in the approach to AKI that shifts away from the primary composite endpoint of death/dialysis, and instead focuses on improving survival and mitigating permanent renal damage, is likely to be more fruitful. We suggest that the current approach of augmenting renal function by increasing the renal blood flow or glomerular filtration rate during AKI may actually worsen outcomes. Analogous to the approach towards adult respiratory distress syndrome that limits ventilator-induced lung injury, we propose the concept of permissive hypofiltration. The primary goals of this approach are: resting the kidney by providing early renal replacement therapy, avoiding the potentially injurious adverse events that occur during AKI (for example, fluid overload, hypophosphatemia, hypothermia, and so forth), and initiating therapies focused on improving survival and mitigating permanent loss of kidney function.
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135
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Park SW, Kim JY, Ham A, Brown KM, Kim M, D'Agati VD, Lee HT. A1 adenosine receptor allosteric enhancer PD-81723 protects against renal ischemia-reperfusion injury. Am J Physiol Renal Physiol 2012; 303:F721-32. [PMID: 22759398 DOI: 10.1152/ajprenal.00157.2012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Activation of A(1) adenosine receptors (ARs) protects against renal ischemia-reperfusion (I/R) injury by reducing necrosis, apoptosis, and inflammation. However, extrarenal side effects (bradycardia, hypotension, and sedation) may limit A(1)AR agonist therapy for ischemic acute kidney injury. Here, we hypothesized that an allosteric enhancer for A(1)AR (PD-81723) protects against renal I/R injury without the undesirable side effects of systemic A(1)AR activation by potentiating the cytoprotective effects of renal adenosine generated locally by ischemia. Pretreatment with PD-81723 produced dose-dependent protection against renal I/R injury in A(1)AR wild-type mice but not in A(1)AR-deficient mice. Significant reductions in renal tubular necrosis, neutrophil infiltration, and inflammation as well as tubular apoptosis were observed in A(1)AR wild-type mice treated with PD-81723. Furthermore, PD-81723 decreased apoptotic cell death in human proximal tubule (HK-2) cells in culture, which was attenuated by a specific A(1)AR antagonist (8-cyclopentyl-1,3-dipropylxanthine). Mechanistically, PD-81723 induced sphingosine kinase (SK)1 mRNA and protein expression in HK-2 cells and in the mouse kidney. Supporting a critical role of SK1 in A(1)AR allosteric enhancer-mediated renal protection against renal I/R injury, PD-81723 failed to protect SK1-deficient mice against renal I/R injury. Finally, proximal tubule sphingosine-1-phosphate type 1 receptors (S1P(1)Rs) are critical for PD-81723-induced renal protection, as mice selectively deficient in renal proximal tubule S1P(1)Rs (S1P(1)R(flox/flox) PEPCK(Cre/-) mice) were not protected against renal I/R injury with PD-81723 treatment. Taken together, our experiments demonstrate potent renal protection with PD-81723 against I/R injury by reducing necrosis, inflammation, and apoptosis through the induction of renal tubular SK1 and activation of proximal tubule S1P(1)Rs. Our findings imply that selectively enhancing A(1)AR activation by locally produced renal adenosine may be a clinically useful therapeutic option to attenuate ischemic acute kidney injury without systemic side effects.
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Affiliation(s)
- Sang Won Park
- Department of Anesthesiology, Columbia University, 630 W. 168th St., New York, NY 10032-3784, USA
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136
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Abstract
Acute renal failure, now referred to as acute kidney injury, is a common and clinically important problem. Acute kidney injury frequently occurs as a result of acute tubular necrosis (ATN), which is often caused by a reduction in systemic blood pressure or renal blood flow (e.g., as observed in severe sepsis or during renal transplantation). The disease course in ATN is variable, including prolonged dialysis-dependence and chronic renal dysfunction, but there is currently no specific therapy for ATN. There is increasing evidence that the inflammatory response in ATN significantly contributes to disease severity and outcome. In this review, we summarize recent developments in the understanding of how the immune system responds to dying cells, and the relevance of these discoveries to ATN. In particular, NLRP3 inflammasome activation and IL-1β-mediated neutrophil recruitment are likely to play a key role and may provide novel therapeutic targets for immunotherapy in ATN.
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Affiliation(s)
- Miriam Berry
- Division of Renal Medicine, Department of Medicine, University of Cambridge, Cambridge, UK
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137
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Proximal tubule sphingosine kinase-1 has a critical role in A1 adenosine receptor-mediated renal protection from ischemia. Kidney Int 2012; 82:878-91. [PMID: 22695326 PMCID: PMC3443517 DOI: 10.1038/ki.2012.224] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Renal ischemia reperfusion injury is a major cause of acute kidney injury. We previously found that renal A1 adenosine receptor (A1AR) activation attenuated multiple cell death pathways including necrosis, apoptosis and inflammation. Here, we tested whether induction of cytoprotective sphingosine kinase (SK)-1 and sphingosine-1 phosphate (S1P) synthesis might be the mechanism of protection. A selective A1AR agonist (CCPA) increased the synthesis of S1P and selectively induced SK-1 in mouse kidney and HK-2 cells. This agonist failed to protect SK1-knockout but protected SK2-knockout mice against renal ischemia reperfusion injury indicating a critical role of SK1 in A1AR-mediated renal protection. Inhibition of SK prevented A1AR-mediated defense against necrosis and apoptosis in HK-2 cells. A selective S1P1R antagonist (W146) and global in vivo gene knockdown of S1P1Rs with small interfering RNA completely abolished the renal protection provided by CCPA. Mice selectively deficient in renal proximal tubule S1P1Rs (S1P1Rflox/flox PEPCKCre/−) were not protected against renal ischemia reperfusion injury by CCPA. Mechanistically, CCPA increased nuclear translocation of hypoxia inducible factor-1α in HK-2 cells and selective hypoxia inducible factor-1α inhibition blocked A1AR-mediated induction of SK1. Thus, proximal tubule SK-1 has a critical role in A1AR-mediated protection against renal ischemia reperfusion injury.
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138
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Abstract
Acute kidney injury (AKI) is the leading cause of nephrology consultation and is associated with high mortality rates. The primary causes of AKI include ischemia, hypoxia, or nephrotoxicity. An underlying feature is a rapid decline in glomerular filtration rate (GFR) usually associated with decreases in renal blood flow. Inflammation represents an important additional component of AKI leading to the extension phase of injury, which may be associated with insensitivity to vasodilator therapy. It is suggested that targeting the extension phase represents an area potential of treatment with the greatest possible impact. The underlying basis of renal injury appears to be impaired energetics of the highly metabolically active nephron segments (i.e., proximal tubules and thick ascending limb) in the renal outer medulla, which can trigger conversion from transient hypoxia to intrinsic renal failure. Injury to kidney cells can be lethal or sublethal. Sublethal injury represents an important component in AKI, as it may profoundly influence GFR and renal blood flow. The nature of the recovery response is mediated by the degree to which sublethal cells can restore normal function and promote regeneration. The successful recovery from AKI depends on the degree to which these repair processes ensue and these may be compromised in elderly or chronic kidney disease (CKD) patients. Recent data suggest that AKI represents a potential link to CKD in surviving patients. Finally, earlier diagnosis of AKI represents an important area in treating patients with AKI that has spawned increased awareness of the potential that biomarkers of AKI may play in the future.
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Affiliation(s)
- David P Basile
- Department of Cellular & Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana, USA.
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139
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Faubel S, Chawla LS, Chertow GM, Goldstein SL, Jaber BL, Liu KD. Ongoing clinical trials in AKI. Clin J Am Soc Nephrol 2012; 7:861-73. [PMID: 22442183 DOI: 10.2215/cjn.12191111] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
AKI is an important public health issue. AKI is a common hospital complication associated with increased in-hospital and long-term mortality, extensive morbidity (including prolonged hospital length of stay), and an estimated annual cost of at least $10 billion in the United States. At present, no specific therapy has been developed to prevent AKI, hasten recovery of kidney function, or abrogate the deleterious systemic effects of AKI. However, recent progress includes establishing a consensus definition of AKI and discovery of novel biomarkers that may allow early detection of AKI. Furthermore, significant insights into the pathophysiology of AKI and its deleterious systemic effects have been gleaned from animal studies. Urgently needed are large, definitive randomized clinical trials testing interventions to prevent and/or treat AKI. This review summarizes and analyzes current ongoing clinical trials registered with clinicaltrials.gov that address prevention or management of AKI. The purpose of this review is to provide a resource for people interested in potential prophylactic and therapeutic approaches to patient care and investigators hoping to plan and execute the next round of randomized clinical trials. Finally, this review discusses research needs that are not addressed by the current clinical trials portfolio and suggests key areas for future research in AKI.
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Affiliation(s)
- Sarah Faubel
- Division of Nephrology, University of Colorado and Denver Veterans Administration Medical Center, Denver, Colorado, USA.
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140
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Katagiri D, Doi K, Honda K, Negishi K, Fujita T, Hisagi M, Ono M, Matsubara T, Yahagi N, Iwagami M, Ohtake T, Kobayashi S, Sugaya T, Noiri E. Combination of two urinary biomarkers predicts acute kidney injury after adult cardiac surgery. Ann Thorac Surg 2012; 93:577-83. [PMID: 22269724 DOI: 10.1016/j.athoracsur.2011.10.048] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2011] [Revised: 10/14/2011] [Accepted: 10/20/2011] [Indexed: 12/31/2022]
Abstract
BACKGROUND Urinary L-type fatty acid-binding protein (L-FABP) has not been evaluated for adult post-cardiac surgery acute kidney injury (AKI) to date. This study was undertaken to evaluate a biomarker panel consisting of urinary L-FABP and N-acetyl-β-D-glucosaminidase (NAG), a more established urinary marker of kidney injury, for AKI diagnosis in adult post-cardiac surgery patients. METHODS This study prospectively evaluated 77 adult patients who underwent cardiac surgery at 2 general hospitals. Urinary L-FABP and NAG were measured before surgery, at intensive care unit arrival after surgery (0 hours), 4, and 12 hours after arrival. The AKI was diagnosed by the Acute Kidney Injury Network criteria. RESULTS Of 77 patients, 28 patients (36.4%) developed AKI after surgery. Urinary L-FABP and NAG were significantly increased. However, receiver operating characteristic (ROC) analysis revealed that the biomarkers' performance was statistically significant but limited for clinical translation (area under the curve of ROC [AUC-ROC] for L-FABP at 4 hours 0.72 and NAG 0.75). Urinary L-FABP showed high sensitivity and NAG detected AKI with high specificity. Therefore, we combined these 2 biomarkers, which revealed that this combination panel can detect AKI with higher accuracy than either biomarker measurement alone (AUC-ROC 0.81). Moreover, this biomarker panel improved AKI risk prediction significantly compared with predictions made using the clinical model alone. CONCLUSIONS When urinary L-FABP and NAG are combined, they can detect AKI adequately, even in a heterogeneous population of adult post-cardiac surgery AKI. Combining 2 markers with different sensitivity and specificity presents a reasonable strategy to improve the diagnostic performance of biomarkers.
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Affiliation(s)
- Daisuke Katagiri
- Department of Nephrology and Endocrinology, The University of Tokyo, Tokyo, Japan
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141
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Abstract
Pre-renal acute kidney injury (AKI) is assumed to represent a physiological response to underperfusion. Its diagnosis is retrospective after a transient rise in plasma creatinine, usually associated with evidence of altered tubular transport, particularly that of sodium. In order to test whether pre-renal AKI is reversible because injury is less severe than that of sustained AKI, we measured urinary biomarkers of injury (cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), γ-glutamyl transpeptidase, IL-18, and kidney injury molecule-1 (KIM-1)) at 0, 12, and 24 h following ICU admission. A total of 529 patients were stratified into groups having no AKI, AKI with recovery by 24 h, recovery by 48 h, or the composite of AKI greater than 48 h or dialysis. Pre-renal AKI was identified in 61 patients as acute injury with recovery within 48 h and a fractional sodium excretion <1%. Biomarker concentrations significantly and progressively increased with the duration of AKI. After restricting the AKI recovery within the 48 h cohort to pre-renal AKI, this increase remained significant. The median concentration of KIM-1, cystatin C, and IL-18 were significantly greater in pre-renal AKI compared with no-AKI, while NGAL and γ-glutamyl transpeptidase concentrations were not significant. The median concentration of at least one biomarker was increased in all but three patients with pre-renal AKI. Thus, the reason why some but not all biomarkers were increased requires further study. The results suggest that pre-renal AKI represents a milder form of injury.
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142
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Weinberg JM, Venkatachalam MA. Preserving postischemic reperfusion in the kidney: a role for extracellular adenosine. J Clin Invest 2012; 122:493-6. [PMID: 22269321 DOI: 10.1172/jci60957] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Several adenosine receptor subtypes on endothelial, epithelial, mesangial, and inflammatory cells have been implicated in ischemic acute kidney injury, a life-threatening condition that frequently complicates the care of hospitalized patients. In this issue of the JCI, Grenz and coworkers provide novel insight into how preservation of postischemic renal perfusion by endothelial cell adenosine A2B receptors is antagonized by adenosine reuptake into proximal tubule cells by equilibrative nucleotide transporter 1, which can be inhibited by dipyridamole. The work suggests that adenosine A2B receptor agonists and inhibition of equilibrative nucleoside transporters by dipyridamole may have therapeutic potential in ischemic acute kidney injury, a condition for which there are currently no specific therapeutic interventions.
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Affiliation(s)
- Joel M Weinberg
- Division of Nephrology, Department of Internal Medicine, Veterans Affairs Ann Arbor Healthcare System, University of Michigan, Ann Arbor, Michigan, USA.
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143
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Phelps CM, Eshelman J, Cruz ED, Pan Z, Kaufman J. Acute kidney injury after cardiac surgery in infants and children: evaluation of the role of angiotensin-converting enzyme inhibitors. Pediatr Cardiol 2012; 33:1-7. [PMID: 21800174 DOI: 10.1007/s00246-011-0046-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Accepted: 06/29/2011] [Indexed: 12/29/2022]
Abstract
Children with congenital heart disease who undergo cardiac surgery are vulnerable to acute kidney injury (AKI). This study sought to evaluate the role of angiotensin-converting enzyme (ACE) inhibitors and other nephrotoxic medications in the risk for the development of AKI in neonates and children undergoing cardiac surgery. A retrospective review of all patients younger than 2 years admitted to the cardiac intensive care unit after cardiac surgery from March 2007 to September 2008 was conducted. Patients were included in the review if they received furosemide alone or in combination with an ACE inhibitor. Creatinine clearance was calculated, and the patient's maximal degree of AKI was classified by pRIFLE. A P value less than 0.05 was considered significant. Of the 319 patients who met the inclusion criteria, 149 (47%) received furosemide therapy alone and 170 (53%) received a combination of furosemide and an ACE inhibitor. Patients in the furosemide-only group (age, 5 months) were older than the patients who received both furosemide and an ACE inhibitor (age, 3.8 months; P = 0.024). Despite statistically higher Aristotle scores in the ACE-inhibitor group, the intraoperative variables did not differ between the two groups. Postoperatively, the ACE-inhibitor group had a decreased creatinine clearance (55.3 ml/min/1.73 m(2)) compared with the furosemide group (64.4 ml/min/1.73 m(2); P = 0.015) and an increased incidence of a pRIFLE maximal score of "F" (odds ratio [OR], 1.75; P = 0.033). However, after adjustment for additional risk factors, no difference in the occurrence of AKI resulted (OR, 0.939; P = 0.85) when patients received an ACE inhibitor. More than half of the study population received ACE inhibitors, but this treatment was not associated with an increase in AKI.
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Regner KR. Editorial Comment to Renoprotective effect of erythropoietin in ischemia/reperfusion injury: possible roles of the Akt/endothelial nitric oxide synthase-dependent pathway. Int J Urol 2011; 19:256. [PMID: 22151694 DOI: 10.1111/j.1442-2042.2011.02938.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kevin R Regner
- Department of Medicine-Nephrology, Medical College of Wisconsin, Milwaukee, Wisconsin, USA.
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Zarjou A, Sanders PW, Mehta RL, Agarwal A. Enabling innovative translational research in acute kidney injury. Clin Transl Sci 2011; 5:93-101. [PMID: 22376265 DOI: 10.1111/j.1752-8062.2011.00302.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Acute kidney injury (AKI) is a common, heterogeneous, and detrimental clinical condition that has significant attributable morbidity and mortality. Despite major advances in understanding the epidemiology, pathogenesis, and outcomes of AKI, preventive measures remain inadequate and therapeutic approaches (except for renal replacement therapy) have largely proven futile so far. Critical to the process of designing rational therapies is translational research, which involves the transition between the basic research discoveries and everyday clinical applications to prevent, diagnose, and treat human diseases. Progress in innovative approaches has been hampered due in part to the reliance on functional markers (serum creatinine and blood urea nitrogen) that are neither sensitive nor specific to diagnose AKI. This limitation has created a great deal of interest and intense investigation to identify a "troponin-like marker" that would facilitate recognition of AKI and allow for timely implementation of the precise therapeutic agent. The other major obstacle in this field is the diverse and complex nature of AKI that involves multiple independent and overlapping pathways, making it difficult to cure AKI with a single approach. In this review, we will summarize the advances, ongoing studies, and future perspectives in the field of translational research of AKI.
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Affiliation(s)
- Abolfazl Zarjou
- Department of Medicine, Division of Nephrology, Nephrology Research and Training Center and Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, Alabama, USA
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146
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147
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Urine biomarkers predict acute kidney injury and mortality in very low birth weight infants. J Pediatr 2011; 159:907-12.e1. [PMID: 21784446 PMCID: PMC5065006 DOI: 10.1016/j.jpeds.2011.05.045] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2010] [Revised: 04/07/2011] [Accepted: 05/25/2011] [Indexed: 01/30/2023]
Abstract
OBJECTIVES To test the hypothesis that noninvasive urinary biomarkers may improve early identification, differentiate causes, and predict outcomes of acute kidney injury (AKI) in very low birth weight subjects. STUDY DESIGN We performed 2 nested case-control studies to compare the ability of 6 urine biomarkers to predict AKI (rise in serum creatinine of at least 0.3 mg/dL) and mortality (death before 36 weeks postmenstrual age). RESULTS Compared to subjects without AKI (n = 21), those with AKI (n = 9) had higher maximum neutrophil gelatinase-associated lipocalin (OR = 1.2 [1.0, 1.6]; P < .01; receiver operator characteristics [ROC] area under the curve [AUC] = .80) and higher maximum osteopontin (OR = 3.2 [1.5, 9.9]; P < .01; ROC AUC = 0.83). Compared with survivors (n = 100), nonsurvivors (n = 23) had higher maximum kidney injury molecule 1 (OR = 1.1 [1.0, 1.2]; P < .02; ROC AUC = 0.64) and higher maximum osteopontin (OR = 1.8 (1.2, 2.7); P < .001; AUC of ROC = 0.78). The combination of biomarkers improved predictability for both AKI and mortality. Controlling for gestational age and birth weight did not affect results considerably. CONCLUSIONS Urinary biomarkers can predict AKI and mortality in very low birth weight infants independent of gestational age and birth weight.
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Park SW, Kim M, Brown KM, D'Agati VD, Lee HT. Inhibition of sphingosine 1-phosphate receptor 2 protects against renal ischemia-reperfusion injury. J Am Soc Nephrol 2011; 23:266-80. [PMID: 22095950 DOI: 10.1681/asn.2011050503] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Activation of the sphingosine 1-phosphate receptor 1 (S1P(1)R) protects against renal ischemia-reperfusion (IR) injury and inflammation, but the role of other members of this receptor family in modulating renal IR injury is unknown. We found that a selective S1P(2)R antagonist protected against renal IR injury in a dose-dependent manner. Consistent with this observation, both S1P(2)R-deficient mice and wild-type mice treated with S1P(2)R small interfering RNA had reduced renal injury after IR. In contrast, a selective S1P(2)R agonist exacerbated renal IR injury. The S1P(2)R antagonist increased sphingosine kinase-1 (SK1) expression via Rho kinase signaling in renal proximal tubules; the S1P(2)R agonist decreased SK1. S1P(2)R antagonism failed to protect the kidneys of SK1-deficient mice or wild-type mice pretreated with an SK1 inhibitor or an S1P(1)R antagonist, suggesting that the renoprotection conferred by S1P(2)R antagonism results from pathways involving activation of S1P(1)R by SK1. In cultured human proximal tubule (HK-2) cells, the S1P(2)R antagonist selectively upregulated SK1 and attenuated both H(2)O(2)-induced necrosis and TNF-α/cycloheximide-induced apoptosis; the S1P(2)R agonist had the opposite effects. In addition, increased nuclear hypoxia inducible factor-1α was critical in mediating the renoprotective effects of S1P(2)R inhibition. Finally, induction of SK1 and S1P(2)R in response to renal IR and S1P(2)R antagonism occurred selectively in renal proximal tubule cells but not in renal endothelial cells. Taken together, these data suggest that S1P(2)R may be a therapeutic target to attenuate the effects of renal IR injury.
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Affiliation(s)
- Sang Wong Park
- Department of Anesthesiology, College of Physicians and Surgeons of Columbia University, New York, NY 10032-3784, USA
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149
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Antonopoulos CN, Kalkanis A, Georgakopoulos G, Sergentanis TN, Rigopoulos DN. Neutrophil gelatinase-associated lipocalin in dehydrated patients: a preliminary report. BMC Res Notes 2011; 4:435. [PMID: 22018285 PMCID: PMC3207993 DOI: 10.1186/1756-0500-4-435] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2011] [Accepted: 10/22/2011] [Indexed: 11/10/2022] Open
Abstract
Background Acute kidney injury has been recognized as a major contributor to end stage renal disease. Although neutrophil gelatinase-associated lipocalin (Ngal) has been reported as a promising biomarker for early detection of acute kidney injury, no study has yet examined its potential clinical impact in patients with normal renal function. The purpose of current study is to investigate possible difference in serum Ngal levels between dehydrated and control patients. Findings A total of twelve patients presented with symptoms of mild dehydration defined by history of diarrheas or vomiting and orthostatic (postural) hypotension and an age and sex matched group of twelve control patients were included. The two groups of patients did not seem to differ in basic clinical and laboratory parameters. Serum Ngal was higher in dehydrated patients when compared to control group (Ngal = 129.4 ± 25.7 ng/mL vs 60.6 ± 0.4 ng/mL, p = 0.02). Ngal was not correlated with age, hemoglobin, white blood cell count, red blood cell count, urea or creatinine. Conclusions The presence of elevated Ngal levels in dehydrated patients may suggest its role as a very sensitive biomarker in even minimal and "silent" prerenal kidney dysfunction
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150
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The reduction of Na/H exchanger-3 protein and transcript expression in acute ischemia-reperfusion injury is mediated by extractable tissue factor(s). Kidney Int 2011; 80:822-831. [PMID: 21814178 DOI: 10.1038/ki.2011.229] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Ischemic renal injury is a formidable clinical problem, the pathophysiology of which is incompletely understood. As the Na/H exchanger-3 (NHE3) mediates the bulk of apical sodium transport and a significant fraction of oxygen consumption in the proximal tubule, we examined mechanisms by which ischemia-reperfusion affects the expression of NHE3. Ischemia-reperfusion dramatically decreased NHE3 protein and mRNA (immunohistochemistry, immunoblot, and RNA blot) in rat kidney cortex and medulla. The decrease in NHE3 protein was uniform throughout all tubules, including those appearing morphologically intact. In the kidney cortex, a decrease in NHE3 surface protein preceded that of NHE3 total protein and mRNA. Kidney homogenates from rats exposed to mild renal ischemia-reduced cell surface NHE3 protein expression in opossum kidney cells in vitro, whereas homogenates from animals with moderate-to-severe ischemia reduced both total NHE3 protein and mRNA. The decrease in total NHE3 protein was dependent on the proteasomal degradation associated with NHE3 ubiquitylation measured by coimmunoprecipitation. The transferable factor(s) from the ischemic homogenate that reduce NHE3 expression were found to be heat sensitive and to be associated with a lipid-enriched fraction, and did not include regulatory RNAs. Thus, transferable factor(s) mediate the ischemia-reperfusion injury-induced decrease in NHE3 of the kidney.
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