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Maringer K, Sims-Lucas S. The multifaceted role of the renal microvasculature during acute kidney injury. Pediatr Nephrol 2016; 31:1231-40. [PMID: 26493067 PMCID: PMC4841763 DOI: 10.1007/s00467-015-3231-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 09/28/2015] [Accepted: 09/29/2015] [Indexed: 12/20/2022]
Abstract
Pediatric acute kidney injury (AKI) represents a complex disease process for clinicians as it is multifactorial in cause and only limited treatment or preventatives are available. The renal microvasculature has recently been implicated in AKI as a strong therapeutic candidate involved in both injury and recovery. Significant progress has been made in the ability to study the renal microvasculature following ischemic AKI and its role in repair. Advances have also been made in elucidating cell-cell interactions and the molecular mechanisms involved in these interactions. The ability of the kidney to repair post AKI is closely linked to alterations in hypoxia, and these studies are elucidated in this review. Injury to the microvasculature following AKI plays an integral role in mediating the inflammatory response, thereby complicating potential therapeutics. However, recent work with experimental animal models suggests that the endothelium and its cellular and molecular interactions are attractive targets to prevent injury or hasten repair following AKI. Here, we review the cellular and molecular mechanisms of the renal endothelium in AKI, as well as repair and recovery, and potential therapeutics to prevent or ameliorate injury and hasten repair.
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Affiliation(s)
- Katherine Maringer
- Rangos Research Center, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA
- Division of Nephrology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Sunder Sims-Lucas
- Rangos Research Center, Children's Hospital of Pittsburgh of UPMC, Pittsburgh, PA, USA.
- Division of Nephrology, Department of Pediatrics, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA.
- Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA, USA.
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Lattenist L, Jansen MPB, Teske G, Claessen N, Meijers JCM, Rezaie AR, Esmon CT, Florquin S, Roelofs JJTH. Activated protein C protects against renal ischaemia/reperfusion injury, independent of its anticoagulant properties. Thromb Haemost 2016; 116:124-33. [PMID: 27052416 DOI: 10.1160/th15-07-0584] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 03/22/2016] [Indexed: 12/20/2022]
Abstract
Acute renal failure, a serious condition characterised by a drastic decline in renal function, often follows ischaemia/reperfusion (I/R) episodes. I/R is characterised by necrosis, inflammation and activation of coagulation, in concert causing renal tissue damage. In this context, activated protein C (APC) might be of importance in the pathogenesis of renal I/R. APC is a serine protease which has anticoagulant but also several anti-inflammatory and cytoprotective effects such as protection of endothelial barrier function. It was our objective to study the role of cytoprotective and anticoagulant functions of APC during renal I/R. C57BL/6j mice subjected to renal I/R were treated with intraperitoneally injected exogenous human APC, or two mutant forms of APC (200 µg/kg) which specifically lack anticoagulant or signalling properties. In a different experiment mice received specific monoclonal antibodies (20 mg/kg) that block the cytoprotective and/or anticoagulant properties of endogenous APC. Treatment with APC reduced tubular injury and enhanced renal function without altering the inflammatory response and did reduce renal fibrin deposition. Administration of APC mutant lacking anticoagulant properties reduced renal damage and enhanced renal function. Blocking the anticoagulant and cytoprotective functions of endogenous APC resulted in elevated tubular damage and reduced tubular cell proliferation, however, without influencing renal function or the inflammatory response. Furthermore, blocking both the anticoagulant and cytoprotective effects of APC resulted in dramatic renal interstitial haemorrhage, indicative of impaired vascular integrity. Blocking only the anticoagulant function of APC did not result in interstitial bleeding. In conclusion, the renoprotective effect of APC during I/R is independent of its anticoagulant properties.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Joris J T H Roelofs
- J. J. T. H. Roelofs, Department of Pathology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, Room M2-130, 1105 AZ Amsterdam, The Netherlands, Tel.: +31 20 56 65626, Fax: +31 20 56 69523, E-mail:
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3
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Bouchard J, Malhotra R, Shah S, Kao YT, Vaida F, Gupta A, Berg DT, Grinnell BW, Stofan B, Tolwani AJ, Mehta RL. Levels of protein C and soluble thrombomodulin in critically ill patients with acute kidney injury: a multicenter prospective observational study. PLoS One 2015; 10:e0120770. [PMID: 25790110 PMCID: PMC4366245 DOI: 10.1371/journal.pone.0120770] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 01/26/2015] [Indexed: 12/23/2022] Open
Abstract
Endothelial dysfunction contributes to the development of acute kidney injury (AKI) in animal models of ischemia reperfusion injury and sepsis. There are limited data on markers of endothelial dysfunction in human AKI. We hypothesized that Protein C (PC) and soluble thrombomodulin (sTM) levels could predict AKI. We conducted a multicenter prospective study in 80 patients to assess the relationship of PC and sTM levels to AKI, defined by the AKIN creatinine (AKI Scr) and urine output criteria (AKI UO). We measured marker levels for up to 10 days from intensive care unit admission. We used area under the curve (AUC) and time-dependent multivariable Cox proportional hazard model to predict AKI and logistic regression to predict mortality/non-renal recovery. Protein C and sTM were not different in patients with AKI UO only versus no AKI. On intensive care unit admission, as PC levels are usually lower with AKI Scr, the AUC to predict the absence of AKI was 0.63 (95%CI 0.44-0.78). The AUC using log10 sTM levels to predict AKI was 0.77 (95%CI 0.62-0.89), which predicted AKI Scr better than serum and urine neutrophil gelatinase-associated lipocalin (NGAL) and cystatin C, urine kidney injury molecule-1 and liver-fatty acid-binding protein. In multivariable models, PC and urine NGAL levels independently predicted AKI (p=0.04 and 0.02) and PC levels independently predicted mortality/non-renal recovery (p=0.04). In our study, PC and sTM levels can predict AKI Scr but are not modified during AKI UO alone. PC levels could independently predict mortality/non-renal recovery. Additional larger studies are needed to define the relationship between markers of endothelial dysfunction and AKI.
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Affiliation(s)
- Josée Bouchard
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, United States of America
- Division of Nephrology, Department of Medicine, Université de Montréal, Montréal, Canada
| | - Rakesh Malhotra
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Shamik Shah
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, United States of America
| | - Yu-Ting Kao
- Division of Biostatistics and Bioinformatics, University of California San Diego, San Diego, California, United States of America
| | - Florin Vaida
- Division of Biostatistics and Bioinformatics, University of California San Diego, San Diego, California, United States of America
| | - Akanksha Gupta
- Biotechnology Discovery Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, United States of America
| | - David T. Berg
- Biotechnology Discovery Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, United States of America
| | - Brian W. Grinnell
- Biotechnology Discovery Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, United States of America
| | - Brenda Stofan
- Division of Nephrology, University of Alabama, Birmingham, Alabama, United States of America
| | - Ashita J. Tolwani
- Division of Nephrology, University of Alabama, Birmingham, Alabama, United States of America
| | - Ravindra L. Mehta
- Division of Nephrology and Hypertension, Department of Medicine, University of California San Diego, San Diego, California, United States of America
- * E-mail: (RLM)
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Zhang P, Li Y, Zhang LD, Wang LH, Wang X, He C, Lin ZF. Proteome changes in mesenteric lymph induced by sepsis. Mol Med Rep 2014; 10:2793-804. [PMID: 25242054 PMCID: PMC4227422 DOI: 10.3892/mmr.2014.2580] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 05/02/2014] [Indexed: 12/11/2022] Open
Abstract
The present study aimed to examine the changes in mesenteric lymph during the development of sepsis and to identify the distinct proteins involved, as targets for further study. The sepsis animal model was constructed by cecal ligation and puncture (CLP). The mesenteric lymph was collected from 28 adult male Sprague-Dawley rats, which were randomly divided into the following four groups (n=7 per group): CLP-6 h, CLP-24 h, sham-6 h and sham-24 h groups. Capillary high performance liquid chromatography-tandem mass spectrometry was performed to analyze the proteome in mesenteric lymph. A comprehensive bioinformatic analysis was then conducted to investigate the distinct proteins. Compared with the sham group, 158 distinct proteins were identified in the lymph samples from the CLP group. Five of these proteins associated with the same lipid metabolism pathway were selected, apolipoprotein E (ApoE), annexin A1 (Anxa1), neutrophil gelatinase-associated lipocalin (NGAL), S100a8 and S100a9. The expression of ApoE, Anxa1, NGAL, S100a8 and S100a9 were all elevated in the progression of sepsis. The five proteins were reported to be closely associated with disease development and may be a potential target for the diagnosis and treatment of sepsis. In conclusion, identifying proteome changes in mesenteric lymph provides a novel perspective to understand the pathological mechanisms underlying sepsis.
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Affiliation(s)
- Ping Zhang
- Emergency Department, Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
| | - Yan Li
- Emergency Department, Shanghai First People's Hospital, Shanghai Jiao Tong University, Shanghai 201620, P.R. China
| | - Lian-Dong Zhang
- Emergency Department, Shuguang Hospital Baoshan Branch, Shanghai University of Traditional Chinese Medicine, Shanghai 201900, P.R. China
| | - Liang-Hua Wang
- Department of Biochemistry and Molecular Biology, Second Military Medical University, Shanghai 200433, P.R. China
| | - Xi Wang
- Emergency Department, Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
| | - Chao He
- Emergency Department, Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
| | - Zhao-Fen Lin
- Emergency Department, Changzheng Hospital, Second Military Medical University, Shanghai 200003, P.R. China
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Heme oxygenase 1 modulates thrombomodulin and endothelial protein C receptor levels to attenuate septic kidney injury. Shock 2014; 40:136-43. [PMID: 23807243 DOI: 10.1097/shk.0b013e31829d23f5] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
This study investigated the effects of heme oxygenase 1 (HO-1) on thrombomodulin (TM) and endothelial protein C receptor (EPCR) expression in sepsis-induced kidney injury. The role of HO-1 was evaluated in a cecal ligation and puncture (CLP)-induced model. Wistar rats were randomly assigned into four groups: sham, CLP, CLP + hemin (an HO-1 inducer), CLP + ZnPP (zinc protoporphyrin IX, an HO-1 inhibitor), and CLP + bilirubin. Compared with the sham group, the CLP group exhibited significantly elevated plasma levels of cystatin C, creatinine, urea nitrogen (blood urea nitrogen), tumor necrosis factor α, interleukin 1β, TM, and EPCR; lower plasma level of activated protein C, shorter prothrombin time and activated partial thromboplastin time; significantly increased microthrombus formation; and lower TM and EPCR mRNA and protein expression in the kidney. The administration of hemin lowered the plasma levels of cystatin C, creatinine, blood urea nitrogen, tumor necrosis factor α, interleukin 1β, TM, and EPCR; elevated plasma level of activated protein C; prolonged prothrombin time and activated partial thromboplastin time; attenuated microthrombus formation; and upregulated the expression of TM and EPCR and mRNA levels of TM and EPCR in the kidney in the CLP + hemin group. In contrast, ZnPP had the opposite effects. The results indicated that the enhanced induction of HO-1 increased the expression of TM and EPCR in the kidney and exerted an anticoagulant effect, thereby attenuating kidney injury in septic rats.
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Vandijck DM, Reynvoet E, Blot SI, Vandecasteele E, Hoste EA. Severe infection, sepsis and acute kidney injury. Acta Clin Belg 2014; 62 Suppl 2:332-6. [PMID: 18283994 DOI: 10.1179/acb.2007.075] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Both severe infection and acute kidney injury (AKI) have a high, and rising incidence in critically ill patients admitted to the intensive care unit (ICU), and are associated with increased in-hospital mortality. Septic AKI patients are more severely ill compared to non-septic AKI patients and have worse outcome. Severe infection is a major cause of AKI in ICU patients, while conversely, AKI patients are at increased risk for infection. The dogma from the past relates the development of AKI in sepsis patients to decreased renal blood flow. However, current data suggest that there is no impairment of renal blood flow in patients with sepsis. The pathogenesis of AKI in sepsis is probably related to cytotoxic effects of inflammation, and impaired microcirculation. In addition, hyperglycaemia, and antimicrobial agent-induced drug nephrotoxicity may contribute to the development of AKI. On the other hand, AKI patients are at greater risk for infection as a result of volume overload, dialysis catheter insertion and secondary manipulation, inflammation of the kidneys leading to'organ cross talk', and impaired host immunity.
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Affiliation(s)
- D M Vandijck
- Department of Intensive Care Medicine, Ghent University Hospital, Ghent, Belgium
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Huang X, Chen Y, Chung CS, Yuan Z, Monaghan SF, Wang F, Ayala A. Identification of B7-H1 as a novel mediator of the innate immune/proinflammatory response as well as a possible myeloid cell prognostic biomarker in sepsis. THE JOURNAL OF IMMUNOLOGY 2013; 192:1091-9. [PMID: 24379123 DOI: 10.4049/jimmunol.1302252] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Identifying relevant mediators responsible for the pathogenesis during sepsis may lead to finding novel diagnostic and therapeutic targets. Recent studies indicate programmed cell death receptor (PD)-1 plays a significant role in the development of immune suppression associated with sepsis. In this study, we determine whether B7-H1, the primary ligand of PD-1, contributes to the pathogenesis of sepsis. We report that B7-H1 is upregulated extensively on various immune cells during sepsis and B7-H1 gene deficiency protects mice from the lethality of sepsis. In terms of the histological development of multiple organ damage and inflammatory cytokine levels in circulation or at infectious site, B7-H1-deficient mice showed a remarkable reduction in these indices when compared with wild-type mice. However, B7-H1 gene-deficient mice did not exhibit a lower bacterial burden when compared with wild-type mice, although they recruited more macrophages and neutrophils into infectious site. In addition, we found that, during sepsis, whereas there were no marked differences affecting ex vivo macrophage cytokine productive capacity between PD-1 and B7-H1 gene-deficient mice, preservation of ex vivo macrophage phagocytic function was only seen in septic PD-1 knockout mouse cells. Finally, higher percentage B7-H1(+) neutrophils in peripheral blood correlated not only with higher levels of pro- and anti-inflammatory cytokines/chemokines (CCL2, IL-6, CXCL2, KC, TNF-α, and IL-10), but with lethal outcome as well. Together, these results indicate B7-H1 contributes to septic morbidity in fashion distinct from PD-1 and suggest B7-H1 expression on neutrophils could be used as a biomarker of septic severity.
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Affiliation(s)
- Xin Huang
- Division of Surgical Research, Department of Surgery, Rhode Island Hospital/Alpert School of Medicine at Brown University, Providence, RI 02903
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Almac E, Johannes T, Bezemer R, Mik EG, Unertl KE, Groeneveld ABJ, Ince C. Activated protein C ameliorates impaired renal microvascular oxygenation and sodium reabsorption in endotoxemic rats. Intensive Care Med Exp 2013; 1:24. [PMID: 26266793 PMCID: PMC4796218 DOI: 10.1186/2197-425x-1-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Accepted: 10/10/2013] [Indexed: 11/19/2022] Open
Abstract
Introduction We aimed to test whether continuous recombinant human activated protein C (APC) administration would be able to protect renal oxygenation and function during endotoxemia in order to provide more insight into the role of coagulation and inflammation in the development of septic acute kidney injury. Methods In anesthetized, mechanically ventilated Wistar rats, endotoxemia was induced by lipopolysaccharide administration (10 mg/kg i.v. over 30 min). One hour later, the rats received fluid resuscitation with 0 (LPS + FR group; n = 8), 10 (APC10 group; n = 8), or 100 (APC100 group; n = 8) μg/kg/h APC for 2 h. Renal microvascular oxygenation in the cortex and medulla were measured using phosphorimetry, and renal creatinine clearance rate and sodium reabsorption were measured as indicators of renal function. Statistical significance of differences between groups was tested using two-way ANOVA with Bonferroni post hoc tests. Results APC did not have notable effects on systemic and renal hemodynamic and oxygenation variables or creatinine clearance. The changes in renal microvascular oxygenation in both the cortex (r = 0.66; p < 0.001) and medulla (r = 0.80; p < 0.001) were correlated to renal sodium reabsorption. Conclusion Renal sodium reabsorption is closely correlated to renal microvascular oxygenation during endotoxemia. In this study, fluid resuscitation and APC supplementation were not significantly effective in protecting renal microvascular oxygenation and renal function. The specific mechanisms responsible for these effects of APC warrant further study. Electronic supplementary material The online version of this article (doi:10.1186/2197-425X-1-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Emre Almac
- Department of Translational Physiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands,
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De Backer D, Orbegozo Cortes D, Donadello K, Vincent JL. Pathophysiology of microcirculatory dysfunction and the pathogenesis of septic shock. Virulence 2013; 5:73-9. [PMID: 24067428 PMCID: PMC3916386 DOI: 10.4161/viru.26482] [Citation(s) in RCA: 256] [Impact Index Per Article: 23.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Multiple experimental and human trials have shown that microcirculatory alterations are frequent in sepsis. In this review, we discuss the various mechanisms that are potentially involved in their development and the implications of these alterations. Endothelial dysfunction, impaired inter-cell communication, altered glycocalyx, adhesion and rolling of white blood cells and platelets, and altered red blood cell deformability are the main mechanisms involved in the development of these alterations. Microcirculatory alterations increase the diffusion distance for oxygen and, due to the heterogeneity of microcirculatory perfusion in sepsis, may promote development of areas of tissue hypoxia in close vicinity to well-oxygenated zones. The severity of microvascular alterations is associated with organ dysfunction and mortality. At this stage, therapies to specifically target the microcirculation are still being investigated.
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Affiliation(s)
- Daniel De Backer
- Department of Intensive Care; Erasme University Hospital; Université Libre de Bruxelles (ULB); Bruxelles, Belgium
| | - Diego Orbegozo Cortes
- Department of Intensive Care; Erasme University Hospital; Université Libre de Bruxelles (ULB); Bruxelles, Belgium
| | - Katia Donadello
- Department of Intensive Care; Erasme University Hospital; Université Libre de Bruxelles (ULB); Bruxelles, Belgium
| | - Jean-Louis Vincent
- Department of Intensive Care; Erasme University Hospital; Université Libre de Bruxelles (ULB); Bruxelles, Belgium
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Renal and urinary levels of endothelial protein C receptor correlate with acute renal allograft rejection. PLoS One 2013; 8:e64994. [PMID: 23717683 PMCID: PMC3661509 DOI: 10.1371/journal.pone.0064994] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2012] [Accepted: 04/21/2013] [Indexed: 11/19/2022] Open
Abstract
The Endothelial Protein C Receptor (EPCR) is expressed on leukocytes, on endothelium of large blood vessels and to a lesser extent on capillaries. Membrane bound EPCR plays an important role in the activation of protein C which has anticoagulant, anti-inflammatory and cytoprotective effects. After cleavage by a protease EPCR is also found as a soluble protein. Acute rejection of kidney allografts can be divided in T-cell-mediated rejection (TCMR) and antibody-mediated (ABMR) rejection. The latter is characterized by strong activation of coagulation. Currently no reliable non-invasive biomarkers are available to monitor rejection. Renal biopsies were available from 81 renal transplant patients (33 without rejection, 26 TCMR and 22 ABMR), we had access to mRNA material, matched plasma and urine samples for a portion of this cohort. Renal EPCR expression was assessed by RT-PCR and immunostaining. Plasma and urine sEPCR levels were measured by ELISA. ABMR patients showed higher levels of EPCR mRNA than TCMR patients. EPCR expression on glomeruli was significantly elevated in ABMR patients than in TCMR or control patients. In the peritubular capillaries EPCR expression was higher in ABMR patients than in control patients. EPCR expression was higher in tubules and arteries of rejection patients than in control patients. Plasma sEPCR levels did not differ. Urine sEPCR levels were more elevated in the ABMR group than in patients with TCMR or without rejection. ROC analysis demonstrated that urinary sEPCR is appropriate to discriminate between ABMR patients and TCMR or control patients. We conclude that urinary sEPCR could be a novel non-invasive biomarker of antibody mediated rejection in renal transplantation.
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Cytoprotective signaling by activated protein C requires protease-activated receptor-3 in podocytes. Blood 2011; 119:874-83. [PMID: 22117049 DOI: 10.1182/blood-2011-07-365973] [Citation(s) in RCA: 94] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The cytoprotective effects of activated protein C (aPC) are well established. In contrast, the receptors and signaling mechanism through which aPC conveys cytoprotection in various cell types remain incompletely defined. Thus, within the renal glomeruli, aPC preserves endothelial cells via a protease-activated receptor-1 (PAR-1) and endothelial protein C receptor-dependent mechanism. Conversely, the signaling mechanism through which aPC protects podocytes remains unknown. While exploring the latter, we identified a novel aPC/PAR-dependent cytoprotective signaling mechanism. In podocytes, aPC inhibits apoptosis through proteolytic activation of PAR-3 independent of endothelial protein C receptor. PAR-3 is not signaling competent itself as it requires aPC-induced heterodimerization with PAR-2 (human podocytes) or PAR-1 (mouse podocytes). This cytoprotective signaling mechanism depends on caveolin-1 dephosphorylation. In vivo aPC protects against lipopolysaccharide-induced podocyte injury and proteinuria. Genetic deletion of PAR-3 impairs the nephroprotective effect of aPC, demonstrating the crucial role of PAR-3 for aPC-dependent podocyte protection. This novel, aPC-mediated interaction of PARs demonstrates the plasticity and cell-specificity of cytoprotective aPC signaling. The evidence of specific, dynamic signaling complexes underlying aPC-mediated cytoprotection may allow the design of cell type specific targeted therapies.
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Kuiper JW, Vaschetto R, Della Corte F, Plötz FB, Groeneveld ABJ. Bench-to-bedside review: Ventilation-induced renal injury through systemic mediator release--just theory or a causal relationship? CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2011; 15:228. [PMID: 21884646 PMCID: PMC3387589 DOI: 10.1186/cc10282] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
We review the current literature on the molecular mechanisms involved in the pathogenesis of acute kidney injury induced by plasma mediators released by mechanical ventilation. A comprehensive literature search in the PubMed database was performed and articles were identified that showed increased plasma levels of mediators where the increase was solely attributable to mechanical ventilation. A subsequent search revealed articles delineating the potential effects of each mediator on the kidney or kidney cells. Limited research has focused specifically on the relationship between mechanical ventilation and acute kidney injury. Only a limited number of plasma mediators has been implicated in mechanical ventilation-associated acute kidney injury. The number of mediators released during mechanical ventilation is far greater and includes pro- and anti-inflammatory mediators, but also mediators involved in coagulation, fibrinolysis, cell adhesion, apoptosis and cell growth. The potential effects of these mediators is pleiotropic and include effects on inflammation, cell recruitment, adhesion and infiltration, apoptosis and necrosis, vasoactivity, cell proliferation, coagulation and fibrinolysis, transporter regulation, lipid metabolism and cell signaling. Most research has focused on inflammatory and chemotactic mediators. There is a great disparity of knowledge of potential effects on the kidney between different mediators. From a theoretical point of view, the systemic release of several mediators induced by mechanical ventilation may play an important role in the pathophysiology of acute kidney injury. However, evidence supporting a causal relationship is lacking for the studied mediators.
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Affiliation(s)
- Jan Willem Kuiper
- Department of Pediatric Intensive Care, VUmc Medical Center, 1007 MB Amsterdam, The Netherlands.
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13
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De Backer D, Donadello K, Taccone FS, Ospina-Tascon G, Salgado D, Vincent JL. Microcirculatory alterations: potential mechanisms and implications for therapy. Ann Intensive Care 2011; 1:27. [PMID: 21906380 PMCID: PMC3224481 DOI: 10.1186/2110-5820-1-27] [Citation(s) in RCA: 149] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2011] [Accepted: 07/19/2011] [Indexed: 12/29/2022] Open
Abstract
Multiple experimental and human trials have shown that microcirculatory alterations are frequent in sepsis. In this review, we discuss the characteristics of these alterations, the various mechanisms potentially involved, and the implications for therapy. Sepsis-induced microvascular alterations are characterized by a decrease in capillary density with an increased number of stopped-flow and intermittent-flow capillaries, in close vicinity to well-perfused capillaries. Accordingly, the surface available for exchange is decreased but also is highly heterogeneous. Multiple mechanisms may contribute to these alterations, including endothelial dysfunction, impaired inter-cell communication, altered glycocalyx, adhesion and rolling of white blood cells and platelets, and altered red blood cell deformability. Given the heterogeneous nature of these alterations and the mechanisms potentially involved, classical hemodynamic interventions, such as fluids, red blood cell transfusions, vasopressors, and inotropic agents, have only a limited impact, and the microcirculatory changes often persist after resuscitation. Nevertheless, fluids seem to improve the microcirculation in the early phase of sepsis and dobutamine also can improve the microcirculation, although the magnitude of this effect varies considerably among patients. Finally, maintaining a sufficient perfusion pressure seems to positively influence the microcirculation; however, which mean arterial pressure levels should be targeted remains controversial. Some trials using vasodilating agents, especially nitroglycerin, showed promising initial results but they were challenged in other trials, so it is difficult to recommend the use of these agents in current practice. Other agents can markedly improve the microcirculation, including activated protein C and antithrombin, vitamin C, or steroids. In conclusion, microcirculatory alterations may play an important role in the development of sepsis-related organ dysfunction. At this stage, therapies to target microcirculation specifically are still being investigated.
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Affiliation(s)
- Daniel De Backer
- Department of Intensive Care, Erasme University Hospital, Université Libre de Bruxelles, Route de Lennik 808, B-1070 Brussels, Belgium.
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Keller SA, Moore CC, Evans SL, McKillop IH, Huynh T. Activated Protein C Alters Inflammation and Protects Renal Function in Sepsis. J Surg Res 2011; 168:e103-9. [DOI: 10.1016/j.jss.2011.01.008] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2010] [Revised: 12/10/2010] [Accepted: 01/04/2011] [Indexed: 12/12/2022]
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White LE, Chaudhary R, Moore LJ, Moore FA, Hassoun HT. Surgical sepsis and organ crosstalk: the role of the kidney. J Surg Res 2010; 167:306-15. [PMID: 21324390 DOI: 10.1016/j.jss.2010.11.923] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2010] [Revised: 11/19/2010] [Accepted: 11/29/2010] [Indexed: 02/06/2023]
Abstract
Acute kidney injury (AKI) is a common complication of hospitalized patients, and clinical outcomes remain poor despite advances in renal replacement therapy. The accepted pathophysiology of AKI in the setting of sepsis has evolved from one of simple decreased renal blood flow to one that involves a more complex interaction of intra-glomerular microcirculatory vasodilation combined with the local release of inflammatory mediators and apoptosis. Evidence from preclinical AKI models suggests that crosstalk occurs between kidneys and other organ systems via soluble and cellular inflammatory mediators and that this involves both the innate and adaptive immune systems. These interactions are reflected by genomic changes and abnormal rates of cellular apoptosis in distant organs including the lungs, heart, gut, liver, and central nervous system. The purpose of this article is to review the influence of AKI, particularly sepsis-associated AKI, on inter-organ crosstalk in the context of systemic inflammation and multiple organ failure (MOF).
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Affiliation(s)
- Laura E White
- Department of Surgery, The Methodist Hospital and Research Institute, Houston Texas, USA
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Urinary excretion of twenty peptides forms an early and accurate diagnostic pattern of acute kidney injury. Kidney Int 2010; 78:1252-62. [DOI: 10.1038/ki.2010.322] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Bae JS, Kim IS, Rezaie AR. Thrombin down-regulates the TGF-beta-mediated synthesis of collagen and fibronectin by human proximal tubule epithelial cells through the EPCR-dependent activation of PAR-1. J Cell Physiol 2010; 225:233-9. [PMID: 20506163 DOI: 10.1002/jcp.22249] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Human proximal tubule (HK-2) cells are commonly used as cellular models to understand the mechanism by which inflammatory mediators cause renal injury. It has been observed that thrombin stimulates the expression of TGF-beta, extracellular matrix (ECM) proteins and proinflammatory cytokines by HK-2 cells. These in vitro responses correlate well with the pathology of glomerular and tubular diseases observed in acute renal injury. HK-2 cells express PAR-1 and the thrombin activation of this receptor has been reported to up-regulate the TGF-beta-mediated expression of ECM proteins, suggesting a possible pathogenic role for PAR-1 signaling by thrombin in acute renal injury. On the other hand, several recent studies have indicated that activated protein C plays a renoprotective role, thus inhibiting the inflammatory responses and attenuating renal injury, presumably by activating the same cell surface receptor. In this study, we show that HK-2 cells express endothelial protein C receptor (EPCR) and that the occupancy of this receptor by protein C switches the signaling specificity of thrombin so that the activation of PAR-1 by thrombin inhibits the TNF-alpha-mediated synthesis of IL-6 and IL-8 and down-regulates the TGF-beta-mediated expression of ECM proteins. These results suggest a possible protective role for EPCR in acute kidney injury.
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Affiliation(s)
- Jong-Sup Bae
- Department of Herbal Pharmaceutical Engineering, College of Herbal Bio-Industry, Daegu Haany University, Gyeongsangbuk-do, Republic of Korea.
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Clancy R, Ginzler EM. Endothelial function and its implications for cardiovascular and renal disease in systemic lupus erythematosus. Rheum Dis Clin North Am 2010; 36:145-60, ix-x. [PMID: 20202596 DOI: 10.1016/j.rdc.2009.12.011] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Vascular manifestations associated with systemic lupus erythematosus (SLE) span a broad range, including vasculopathy. An understudied pathway of this morbidity is a repair component. Recent studies have elevated the anti-injury biomarkers, adiponectin and membrane endothelial protein C receptor (EPCR), for consideration with roles to antagonize premature atherosclerosis and SLE nephritis, respectively. For example, adiponectin was found to serve as an independent predictor of carotid plaque, and its elevations were persistent over more than one visit. Unexpectedly, this biomarker was present despite clinical quiescence. In vasculopathy as a comorbidity to SLE nephritis, the persistent expression of membrane EPCR at peritubular capillaries may represent a response to the local cues of a deficit of active protein C. Under conditions of unresolved morbidity, higher levels of adiponectin and membrane EPCR may represent a physiologic attempt to limit further endothelial damage, and the observed increase in plaque and progression of SLE nephritis represent an overwhelming of this reparative process by disease-provoking stimuli.
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Abstract
The development of organ failure determines the course and prognosis of the septic patient. Although several successful clinical trials in recent years have raised the enthusiasm of intensivists, severe sepsis and septic shock still have an increasing incidence with more or less unchanged mortality. Recent sepsis research, including progress made in definitions, epidemiology, pathophysiology, diagnosis, standard and adjunctive therapy, and experimental approaches, is encouraging. This includes genomic information for stratifying subgroups of patients, a broader field of laboratory diagnostics due to clinical studies, and basic research on the cellular mechanisms of inflammation and organ dysfunction. Furthermore, new findings in pathogenesis and therapeutic approaches to organ failure merit attention. In this review, state-of-the-art publications are presented to elucidate the possible impact of sepsis-induced organ failure on clinical routine.
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Affiliation(s)
- Herwig Gerlach
- Vivantes-Klinikum Neukoelln, Klinik für Anaesthesie, operative Intensivmedizin und Schmerztherapie, Rudower Strasse 48, D-12313 Berlin, Germany.
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Homsi E, Brito SMD, Janino P. Silymarin exacerbates p53-mediated tubular apoptosis in glycerol-induced acute kidney injury in rats. Ren Fail 2010; 32:623-32. [DOI: 10.3109/08860221003778064] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
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Joannidis M, Druml W, Forni LG, Groeneveld ABJ, Honore P, Oudemans-van Straaten HM, Ronco C, Schetz MRC, Woittiez AJ. Prevention of acute kidney injury and protection of renal function in the intensive care unit. Expert opinion of the Working Group for Nephrology, ESICM. Intensive Care Med 2010; 36:392-411. [PMID: 19921152 DOI: 10.1007/s00134-009-1678-y] [Citation(s) in RCA: 112] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2008] [Accepted: 08/13/2009] [Indexed: 12/18/2022]
Abstract
BACKGROUND Acute renal failure on the intensive care unit is associated with significant mortality and morbidity. OBJECTIVES To determine recommendations for the prevention of acute kidney injury (AKI), focusing on the role of potential preventative maneuvers including volume expansion, diuretics, use of inotropes, vasopressors/vasodilators, hormonal interventions, nutrition, and extracorporeal techniques. METHOD A systematic search of the literature was performed for studies using these potential protective agents in adult patients at risk for acute renal failure/kidney injury between 1966 and 2009. The following clinical conditions were considered: major surgery, critical illness, sepsis, shock, and use of potentially nephrotoxic drugs and radiocontrast media. Where possible the following endpoints were extracted: creatinine clearance, glomerular filtration rate, increase in serum creatinine, urine output, and markers of tubular injury. Clinical endpoints included the need for renal replacement therapy, length of stay, and mortality. Studies are graded according to the international Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) group system. CONCLUSIONS AND RECOMMENDATIONS Several measures are recommended, though none carries grade 1A. We recommend prompt resuscitation of the circulation with special attention to providing adequate hydration whilst avoiding high-molecular-weight hydroxy-ethyl starch (HES) preparations, maintaining adequate blood pressure using vasopressors in vasodilatory shock. We suggest specific vasodilators [corrected] under strict hemodynamic control, sodium bicarbonate for emergency procedures administering contrast media, and periprocedural hemofiltration in severe chronic renal insufficiency undergoing coronary intervention. ELECTRONIC SUPPLEMENTARY MATERIAL The online version of this article (doi:10.1007/s00134-009-1678-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Michael Joannidis
- Medical Intensive Care Unit, Department of Internal Medicine I, Medical University Innsbruck, Anichstasse 31, 6020 Innsbruck, Austria.
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Benoit DD, Hoste EA. Acute Kidney Injury in Critically Ill Patients with Cancer. Crit Care Clin 2010; 26:151-79. [DOI: 10.1016/j.ccc.2009.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Abstract
PURPOSE OF REVIEW To present the recent findings obtained in clinical and experimental studies examining microcirculatory alterations in sepsis, their link to mitochondrial dysfunction, and current knowledge regarding the impact of these alterations on the outcome of septic patients. RECENT FINDINGS Interlinked by a mutual cascade effect and driven by the host-pathogen interaction, microcirculatory and mitochondrial functions are impaired during sepsis. Mitochondrial respiration seems to evolve during the course of sepsis, demonstrating a change from reversible to irreversible inhibition. The spatiotemporal heterogeneity of microcirculatory and mitochondrial dysfunction suggests that these processes may be compartmentalized. Although a causal relationship between mitochondrial and microcirculatory dysfunction and organ failure in sepsis is supported by an increasing number of studies, adaptive processes have also emerged as part of microcirculatory and mitochondrial alterations. Treatments for improving or preserving microcirculatory, mitochondrial function, or both seem to yield a better outcome in patients. SUMMARY Even though there is evidence that microcirculatory and mitochondrial dysfunction plays a role in the development of sepsis-induced organ failure, their interaction and respective contribution to the disease remains poorly understood. Future research is necessary to better define such relationships in order to identify therapeutic targets and refine treatment strategies.
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Wang Y, Huang WC, Wang CY, Tsai CC, Chen CL, Chang YT, Kai JI, Lin CF. Inhibiting glycogen synthase kinase-3 reduces endotoxaemic acute renal failure by down-regulating inflammation and renal cell apoptosis. Br J Pharmacol 2009; 157:1004-13. [PMID: 19508392 DOI: 10.1111/j.1476-5381.2009.00284.x] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND AND PURPOSE Excessive inflammation and apoptosis are pathological features of endotoxaemic acute renal failure. Activation of glycogen synthase kinase-3 (GSK-3) is involved in inflammation and apoptosis. We investigated the effects of inhibiting GSK-3 on lipopolysaccharide (LPS)-induced acute renal failure, nuclear factor-kappaB (NF-kappaB), inflammation and apoptosis. EXPERIMENTAL APPROACH The effects of inhibiting GSK-3 with inhibitors, including lithium chloride (LiCl) and 6-bromo-indirubin-3'-oxime (BIO), on LPS-treated (15 mg x kg(-1)) C3H/HeN mice (LiCl, 40 mg x kg(-1) and BIO, 2 mg x kg(-1)) and LPS-treated (1 microg x mL(-1)) renal epithelial cells (LiCl, 20 mM and BIO, 5 microM) were studied. Mouse survival was monitored and renal function was analysed by histological and serological examination. Cytokine and chemokine production, and cell apoptosis were measured by enzyme-linked immunosorbent assay and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling staining, respectively. Activation of NF-kappaB and GSK-3 was determined by immunostaining and Western blotting, respectively. KEY RESULTS Mice treated with GSK-3 inhibitors showed decreased mortality, renal tubular dilatation, vacuolization and sloughing, blood urea nitrogen, creatinine and renal cell apoptosis in response to endotoxaemia. Inhibiting GSK-3 reduced LPS-induced tumour necrosis factor-alpha (TNF-alpha) and CCL5/RANTES (released upon activation of normal T-cells) in vivo in mice and in vitro in murine kidney cortical collecting duct epithelial M1 cells. Inhibiting GSK-3 did not block TNF-alpha-induced cytotoxicity in rat kidney proximal tubular epithelial NRK52E or in M1 cells. CONCLUSIONS AND IMPLICATIONS These results suggest that GSK-3 inhibition protects against endotoxaemic acute renal failure mainly by down-regulating pro-inflammatory TNF-alpha and RANTES.
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Affiliation(s)
- Y Wang
- Department of Microbiology and Immunology, National Cheng Kung University Medical College, Tainan 701, Taiwan
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25
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Link between coagulation abnormalities and microcirculatory dysfunction in critically ill patients. Curr Opin Anaesthesiol 2009; 22:150-4. [DOI: 10.1097/aco.0b013e328328d1a1] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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PD-1 expression by macrophages plays a pathologic role in altering microbial clearance and the innate inflammatory response to sepsis. Proc Natl Acad Sci U S A 2009; 106:6303-8. [PMID: 19332785 DOI: 10.1073/pnas.0809422106] [Citation(s) in RCA: 397] [Impact Index Per Article: 26.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sepsis, a leading cause of death worldwide, involves concomitant expression of an overzealous inflammatory response and inefficient bacterial clearance. Macrophage function is pivotal to the development of these two aspects during sepsis; however, the mechanisms underlying these changes remain unclear. Here we report that the PD-1:PD-L pathway appears to be a determining factor of the outcome of sepsis, regulating the delicate balance between effectiveness and damage by the antimicrobial immune response. To this end we observed that PD-1(-/-) mice were markedly protected from the lethality of sepsis, accompanied by a decreased bacterial burden and suppressed inflammatory cytokine response. To the extent that this is a macrophage-specific aspect of the effects of PD-1, we found the following: first, peritoneal macrophages expressed significantly higher levels of PD-1 during sepsis, which was associated with their development of cellular dysfunction; second, when peritoneal macrophages were depleted (using clodronate liposomes) from PD-1(-/-) mice, the animals' bactericidal capacity was lowered, their inflammatory cytokine levels were elevated, and protection from septic lethality was diminished; and third, blood monocytes from both septic mice and patients with septic shock shared markedly increased PD-1 levels. Together, these data suggest that PD-1 may not only be a dysfunctional marker/effector of macrophages/monocytes, but may also be a potential therapeutic target for designing measures to modulate the innate immune response, thereby preventing the detrimental effects of sepsis.
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Izmirly PM, Barisoni L, Buyon JP, Kim MY, Rivera TL, Schwartzman JS, Weisstuch JM, Liu DT, Bernstein S, Tseng CE, Belmont HM, Esmon CT, Merrill JT, Askanase AD, Thomas DB, Clancy RM. Expression of endothelial protein C receptor in cortical peritubular capillaries associates with a poor clinical response in lupus nephritis. Rheumatology (Oxford) 2009; 48:513-9. [PMID: 19286697 DOI: 10.1093/rheumatology/kep034] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE To study the membrane expression of endothelial protein C receptor (mEPCR) in the renal microvasculature in lupus nephritis (LN) as a potential marker of injury and/or prognostic indicator for response to therapy. METHODS mEPCR expression was analysed by immunohistochemistry in normal kidney and in 59 biopsies from 49 patients with LN. Clinical parameters were assessed at baseline, 6 months and 1 year. RESULTS mEPCR was expressed in the medulla, arterial endothelium and cortical peritubular capillaries (PTCs) in all biopsies with LN but not in the cortical PTCs of normal kidney. Positive mEPCR staining in >25% of the PTCs was observed in 16/59 biopsies and associated with poor response to therapy. Eleven (84.6%) of 13 patients with positive staining for mEPCR in >25% of the PTCs and follow-up at 6 months did not respond to therapy, compared with 8/28 (28.6%) with mEPCR staining in < or =25% PTCs, P = 0.0018. At 1 year, 10 (83.3%) of 12 patients with positive mEPCR staining in >25% of the PTCs did not respond to therapy (with two progressing to end-stage renal disease) compared with 8/24 (33.3%) with positive staining in < or =25% of the PTCs, P = 0.0116. Although tubulo-interstitial damage (TID) was always accompanied by mEPCR, this endothelial marker was extensively expressed in the absence of TID suggesting that poor response could not be attributed solely to increased TID. mEPCR expression was independent of International Society of Nephrology/Renal Pathology Society class, activity and chronicity indices. CONCLUSION Increased mEPCR expression in PTCs may represent a novel marker of poor response to therapy for LN.
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Affiliation(s)
- Peter M Izmirly
- Department of Medicine, Division of Rheumatology, New York University School of Medicine, NY, USA.
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Gupta A, Gerlitz B, Richardson MA, Bull C, Berg DT, Syed S, Galbreath EJ, Swanson BA, Jones BE, Grinnell BW. Distinct functions of activated protein C differentially attenuate acute kidney injury. J Am Soc Nephrol 2008; 20:267-77. [PMID: 19092124 DOI: 10.1681/asn.2008030294] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Administration of activated protein C (APC) protects from renal dysfunction, but the underlying mechanism is unknown. APC exerts both antithrombotic and cytoprotective properties, the latter via modulation of protease-activated receptor-1 (PAR-1) signaling. We generated APC variants to study the relative importance of the two functions of APC in a model of LPS-induced renal microvascular dysfunction. Compared with wild-type APC, the K193E variant exhibited impaired anticoagulant activity but retained the ability to mediate PAR-1-dependent signaling. In contrast, the L8W variant retained anticoagulant activity but lost its ability to modulate PAR-1. By administering wild-type APC or these mutants in a rat model of LPS-induced injury, we found that the PAR-1 agonism, but not the anticoagulant function of APC, reversed LPS-induced systemic hypotension. In contrast, both functions of APC played a role in reversing LPS-induced decreases in renal blood flow and volume, although the effects on PAR-1-dependent signaling were more potent. Regarding potential mechanisms for these findings, APC-mediated PAR-1 agonism suppressed LPS-induced increases in the vasoactive peptide adrenomedullin and infiltration of iNOS-positive leukocytes into renal tissue. However, the anticoagulant function of APC was responsible for suppressing LPS-induced stimulation of the proinflammatory mediators ACE-1, IL-6, and IL-18, perhaps accounting for its ability to modulate renal hemodynamics. Both variants reduced active caspase-3 and abrogated LPS-induced renal dysfunction and pathology. We conclude that although PAR-1 agonism is solely responsible for APC-mediated improvement in systemic hemodynamics, both functions of APC play distinct roles in attenuating the response to injury in the kidney.
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Affiliation(s)
- Akanksha Gupta
- Biotechnology Discovery Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285-0444, USA
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Lameire N, Van Biesen W, Hoste E, Vanholder R. The prevention of acute kidney injury: an in-depth narrative review Part 1: volume resuscitation and avoidance of drug- and nephrotoxin-induced AKI. NDT Plus 2008; 1:392-402. [PMID: 28657002 PMCID: PMC5477885 DOI: 10.1093/ndtplus/sfn162] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
This narrative clinical review in two parts discusses the prevention of clinical acute kidney injury (AKI). The first part focuses on general prevention measures, including identification of individuals at high risk for AKI, and on the role of volume expansion and fluid therapy. The latter discusses the timing, the goals, the selection of the fluids and the haemodynamic management of the patient receiving parenteral fluids for the prevention of AKI. In addition, this part summarizes the interaction of intensivist-nephrologist in the ICU with attention to tight glycaemia control and the use of low doses of corticoids in the septic shock patients. Finally, the avoidance of drug- and nephrotoxin-induced AKI is discussed. The second part of this review will summarize the possible pharmacological interventions in the patient at risk.
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Affiliation(s)
| | | | - Eric Hoste
- Intensive Care Unit, University Hospital, Ghent, Belgium
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Abstract
PURPOSE OF REVIEW To discuss the potential use of recombinant activated protein C (aPC) variants with altered bioactivity in sepsis therapy. RECENT FINDINGS Since the initial Protein C Worldwide Evaluation in Severe Sepsis trial demonstrating efficacy of aPC therapy to reduce mortality of severe sepsis, follow-up studies have failed to resolve concerns about the low overall risk-to-benefit ratio of this therapy and suggest that it might only be effective in severely ill patients with the most aggravated forms of coagulopathy. New studies begin to shed light on the potential mechanisms of how aPC therapy may alter sepsis outcome, and how recombinant aPC variants with altered bioactivities may improve the efficacy and safety of this therapy. SUMMARY aPC variants with selectively diminished antithrombotic activity, but normal cytoprotective potential, may allow more efficient dosing without increasing adverse bleeding effects and therefore provide a safer and possibly more efficient alternative to normal aPC. Critical questions about the precise mechanisms by which aPC therapy reduces mortality remain to be resolved in order to identify patients most likely to benefit from it and to reevaluate potential efficacy of aPC therapy in children and patients with less than severe sepsis.
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Janssen van Doorn K, Spapen H, Geers C, Diltoer M, Shabana W. Sepsis-related acute kidney injury: a protective effect of drotrecogin alpha (activated) treatment? Acta Anaesthesiol Scand 2008; 52:1259-64. [PMID: 18823466 DOI: 10.1111/j.1399-6576.2008.01738.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
BACKGROUND Drotrecogin alpha activated (DrotAA) is licensed for treatment of patients with severe sepsis and organ failure. Among the latter, acute kidney injury (AKI), defined as the persistence of oligo-anuria following adequate resuscitation, is one of the most apprehended. We conducted a prospective, observational, and controlled study to test the hypothesis that DrotAA beneficially affected the evolution and outcome of AKI, complicating acute sepsis-induced cardiopulmonary failure. METHODS Forty-six patients were studied. Thirty subjects received standard treatment for sepsis without DrotAA. In the remaining 16 patients, DrotAA was added as a continuous infusion of 24 microg/kg/h for 96 h. RESULTS Mean age, causes of sepsis, and severity/organ failure scores were comparable between patients treated with or without DrotAA. Mortality at 28 days was high and comparable between both treatment groups (56% vs. 69%, DrotAA vs. no DrotAA; P=0.5). When oligo-anuria was present at the start of the study, it persisted during treatment in all patients, with no significant difference between groups. Both treatment groups presented with baseline mean daily fractional excretion of sodium values >2% that remained high during the observation period, regardless of whether DrotAA was given or not. Kidney histology showed a preserved renal architecture with tubular necrosis in all specimens. Similar glomerular, tubulo-interstitial, and vascular alterations were present in both treatment groups. CONCLUSION In this small cohort of patients with severe sepsis who received adjuvant DrotAA treatment, no effect on urine output, tubular function, or mortality could be demonstrated.
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Affiliation(s)
- K Janssen van Doorn
- Department of Critical Care and Nephrology, St Vincentius Hospital, Antwerp, Belgium
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Legrand M, Mik EG, Johannes T, Payen D, Ince C. Renal hypoxia and dysoxia after reperfusion of the ischemic kidney. MOLECULAR MEDICINE (CAMBRIDGE, MASS.) 2008. [PMID: 18488066 DOI: 10.2119/2008-00006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ischemia is the most common cause of acute renal failure. Ischemic-induced renal tissue hypoxia is thought to be a major component in the development of acute renal failure in promoting the initial tubular damage. Renal oxygenation originates from a balance between oxygen supply and consumption. Recent investigations have provided new insights into alterations in oxygenation pathways in the ischemic kidney. These findings have identified a central role of microvascular dysfunction related to an imbalance between vasoconstrictors and vasodilators, endothelial damage and endothelium-leukocyte interactions, leading to decreased renal oxygen supply. Reduced microcirculatory oxygen supply may be associated with altered cellular oxygen consumption (dysoxia), because of mitochondrial dysfunction and activity of alternative oxygen-consuming pathways. Alterations in oxygen utilization and/or supply might therefore contribute to the occurrence of organ dysfunction. This view places oxygen pathways' alterations as a potential central player in the pathogenesis of acute kidney injury. Both in regulation of oxygen supply and consumption, nitric oxide seems to play a pivotal role. Furthermore, recent studies suggest that, following acute ischemic renal injury, persistent tissue hypoxia contributes to the development of chronic renal dysfunction. Adaptative mechanisms to renal hypoxia may be ineffective in more severe cases and lead to the development of chronic renal failure following ischemia-reperfusion. This paper is aimed at reviewing the current insights into oxygen transport pathways, from oxygen supply to oxygen consumption in the kidney and from the adaptation mechanisms to renal hypoxia. Their role in the development of ischemia-induced renal damage and ischemic acute renal failure are discussed.
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Affiliation(s)
- Matthieu Legrand
- Department of Physiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Legrand M, Mik EG, Johannes T, Payen D, Ince C. Renal hypoxia and dysoxia after reperfusion of the ischemic kidney. Mol Med 2008; 14:502-16. [PMID: 18488066 DOI: 10.2119/2008-00006.legrand] [Citation(s) in RCA: 193] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Accepted: 04/17/2008] [Indexed: 12/18/2022] Open
Abstract
Ischemia is the most common cause of acute renal failure. Ischemic-induced renal tissue hypoxia is thought to be a major component in the development of acute renal failure in promoting the initial tubular damage. Renal oxygenation originates from a balance between oxygen supply and consumption. Recent investigations have provided new insights into alterations in oxygenation pathways in the ischemic kidney. These findings have identified a central role of microvascular dysfunction related to an imbalance between vasoconstrictors and vasodilators, endothelial damage and endothelium-leukocyte interactions, leading to decreased renal oxygen supply. Reduced microcirculatory oxygen supply may be associated with altered cellular oxygen consumption (dysoxia), because of mitochondrial dysfunction and activity of alternative oxygen-consuming pathways. Alterations in oxygen utilization and/or supply might therefore contribute to the occurrence of organ dysfunction. This view places oxygen pathways' alterations as a potential central player in the pathogenesis of acute kidney injury. Both in regulation of oxygen supply and consumption, nitric oxide seems to play a pivotal role. Furthermore, recent studies suggest that, following acute ischemic renal injury, persistent tissue hypoxia contributes to the development of chronic renal dysfunction. Adaptative mechanisms to renal hypoxia may be ineffective in more severe cases and lead to the development of chronic renal failure following ischemia-reperfusion. This paper is aimed at reviewing the current insights into oxygen transport pathways, from oxygen supply to oxygen consumption in the kidney and from the adaptation mechanisms to renal hypoxia. Their role in the development of ischemia-induced renal damage and ischemic acute renal failure are discussed.
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Affiliation(s)
- Matthieu Legrand
- Department of Physiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands.
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Simkova V, Baumgart K, Radermacher P, Barth E, Calzia E. Year in review 2006: Critical Care--Multiple organ failure, sepsis, and shock. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2008; 11:221. [PMID: 17764584 PMCID: PMC2206506 DOI: 10.1186/cc5938] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In 2006, Critical Care provided important and clinically relevant research data in the field of multiple organ failure, sepsis, and shock. This review summarizes the results of the experimental studies and clinical trials and discusses them in the context of the relevant scientific and clinical background.
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Affiliation(s)
- Vladislava Simkova
- Anesteziologicko-resuscitacni klinika, Fakultni nemocnice u sv, Anny, Pekarska 53, 656 00 Brno, Czech Republic
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Richardson MA, Gupta A, O'Brien LA, Berg DT, Gerlitz B, Syed S, Sharma GR, Cramer MS, Heuer JG, Galbreath EJ, Grinnell BW. Treatment of sepsis-induced acquired protein C deficiency reverses Angiotensin-converting enzyme-2 inhibition and decreases pulmonary inflammatory response. J Pharmacol Exp Ther 2008; 325:17-26. [PMID: 18182560 DOI: 10.1124/jpet.107.130609] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The protein C (PC) pathway plays an important role in vascular and immune function, and acquired deficiency during sepsis is associated with increased mortality in both animal models and in clinical studies. However, the association of acquired PC deficiency with the pathophysiology of lung injury is unclear. We hypothesized that low PC induced by sepsis would associate with increased pulmonary injury and that replacement with activated protein C (APC) would reverse the activation of pathways associated with injury. Using a cecal ligation and puncture (CLP) model of polymicrobial sepsis, we examined the role of acquired PC deficiency on acute lung injury assessed by analyzing changes in pulmonary pathology, chemokine response, inducible nitric-oxide synthase (iNOS), and the angiotensin pathway. Acquired PC deficiency was strongly associated with an increase in lung inflammation and drivers of pulmonary injury, including angiotensin (Ang) II, thymus and activation-regulated chemokine, plasminogen activator inhibitor (PAI)-1, and iNOS. In contrast, the protective factor angiotensin-converting enzyme (ACE)-2 was significantly suppressed in animals with acquired PC deficiency. The endothelial protein C receptor, required for the cytoprotective signaling of APC, was significantly increased post-CLP, suggesting a compensatory up-regulation of the signaling receptor. Treatment of septic animals with APC reduced pulmonary pathology, suppressed the macrophage inflammatory protein family chemokine response, iNOS expression, and PAI-1 activity and up-regulated ACE-2 expression with concomitant reduction in AngII peptide. These data demonstrate a clear link between acquired PC deficiency and pulmonary inflammatory response in the rat sepsis model and provide support for the concept of APC as a replacement therapy in acute lung injury associated with acquired PC deficiency.
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Affiliation(s)
- Mark A Richardson
- Biotechnology Discovery Research, Lilly Research Laboratories, Lilly Corporate Center, Indianapolis, IN 46285, USA
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Activated Protein C Decreases Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand by an EPCR- Independent Mechanism Involving Egr-1/Erk-1/2 Activation. Arterioscler Thromb Vasc Biol 2007; 27:2634-41. [DOI: 10.1161/atvbaha.107.153734] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background—
APC is an antithrombotic and antiinflammatory serine protease that plays an important role in vascular function. We report that APC can suppress the proapoptotic mediator TRAIL in human umbilical vein endothelial cells, and we have investigated the signaling mechanism.
Methods and Results—
APC inhibited endothelial TRAIL expression and secretion and its induction by cell activation. To explore the mechanism, we examined factors associated with TRAIL regulation and demonstrated that APC increased the level of EGR-1, a transcriptional factor known to suppress the TRAIL promoter. APC also induced a significant increase in phosphorylation of ERK-1/2, required to activate EGR-1 expression. Activation of ERK-1/2 was dependent on the protease activated receptor-1 (PAR-1), but independent of the endothelial protein C receptor (EPCR). Using siRNA, we found that the effect of APC on the EGR-1/ERK signaling required for TRAIL inhibition was dependent on the S1P1 receptor and S1P1 kinase.
Conclusions—
Our data suggest that APC may provide cytoprotective activity by activating the ERK pathway, which upregulates EGR-1 thereby suppressing the expression of TRAIL. Moreover, we provide evidence that APC can induce a cell signaling response through a PAR-1/S1P1-dependent but EPCR-independent mechanism.
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Ramesh G, Zhang B, Uematsu S, Akira S, Reeves WB. Endotoxin and cisplatin synergistically induce renal dysfunction and cytokine production in mice. Am J Physiol Renal Physiol 2007; 293:F325-32. [PMID: 17494092 DOI: 10.1152/ajprenal.00158.2007] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A major toxicity of the cancer chemotherapeutic agent cisplatin is acute renal failure. Sepsis is a common cause of acute renal failure in humans and patients who receive cisplatin are at increased risk for sepsis. Accordingly, this study examined the interactions between cisplatin and endotoxin in vivo with respect to renal function and cytokine production. Mice were treated with either a single dose of cisplatin or two doses of LPS administered 24 h apart, or both agents in combination. Administration of 10 mg/kg cisplatin had no effect on blood urea nitrogen or creatinine levels throughout the course of the study. LPS resulted in a modest rise in blood urea nitrogen at 24 and 48 h, which returned to normal by 72 h. In contrast, mice treated with both cisplatin and LPS developed severe renal failure and an increase in mortality. Urine, but not serum, TNF-alpha levels showed a synergistic increase by cisplatin and LPS. Urinary IL-6, MCP-1, KC, and GM-CSF also showed a synergistic increase with cisplatin+LPS treatment. The renal dysfunction induced by cisplatin+LPS was completely dependent on TLR4 signaling and partially dependent on TNF-alpha production. Increased cytokine production was associated with a moderate increase in infiltrating leukocytes which was not different between cisplatin+LPS and LPS alone. These results indicate that cisplatin and LPS act synergistically to produce nephrotoxicity which may involve proinflammatory cytokine production.
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Affiliation(s)
- Ganesan Ramesh
- Division of Nephrology, Pennsylvania State College of Medicine, 500 Univ. Dr., Hershey, PA 17033, USA
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