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Batlle D, Hassler L, Wysocki J. ACE2, From the Kidney to SARS-CoV-2: Donald Seldin Award Lecture 2023. Hypertension 2025; 82:166-180. [PMID: 39624896 DOI: 10.1161/hypertensionaha.124.22064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2025]
Abstract
ACE2 (angiotensin-converting enzyme 2) is a monocarboxypeptidase that cleaves Ang II (angiotensin II) among other substrates. ACE2 is present in the cell membrane of many organs, most abundantly in epithelial cells of kidney proximal tubules and the small intestine, and also exists in soluble forms in plasma and body fluids. Membrane-bound ACE2 exerts a renoprotective action by metabolizing Ang II and therefore attenuating the undesirable actions of excess Ang II. Therefore, soluble ACE2, by downregulating this peptide, may exert a therapeutic action. Our laboratory has designed ACE2 truncates that pass the glomerular filtration barrier to target the kidney renin-angiotensin system directly and, therefore, compensate for loss of kidney membrane-bound ACE2. Membrane-bound ACE2 is also the essential receptor for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Soluble ACE2 proteins have been studied as a way to intercept SARS-CoV-2 from binding to membrane-bound ACE2 and prevent cell entry of SARS-CoV-2 altogether. We bioengineered a soluble ACE2 protein, termed ACE2 618-DDC-ABD, with increased binding affinity for SARS-CoV-2 and prolonged duration of action, which, when administered intranasally, provides near-complete protection from lethality in k18hACE2 mice infected with different SARS-CoV-2 variants. The main advantage of soluble ACE2 proteins for the neutralization of SARS-CoV-2 is their immediate onset of action and universality for current and future emerging SARS-CoV-2 variants. It is notable that ACE2 is critically involved in 2 dissimilar functions: as a receptor for cell entry of many coronaviruses and as an enzyme in the metabolism of Ang II, and yet in both cases, it is a therapeutic target.
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Affiliation(s)
- Daniel Batlle
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Luise Hassler
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Jan Wysocki
- Division of Nephrology/Hypertension, Department of Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL
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Shirazi M, Cianfarini C, Ismail A, Wysocki J, Wang JJ, Ye M, Zhang ZJ, Batlle D. Altered kidney distribution and loss of ACE2 into the urine in acute kidney injury. Am J Physiol Renal Physiol 2024; 327:F412-F425. [PMID: 38961845 PMCID: PMC11460339 DOI: 10.1152/ajprenal.00237.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 05/28/2024] [Accepted: 06/17/2024] [Indexed: 07/05/2024] Open
Abstract
There are diverse pathophysiological mechanisms involved in acute kidney injury (AKI). Among them, overactivity of the renin-angiotensin system (RAS) has been described. Angiotensin-converting enzyme 2 (ACE2) is a tissue RAS enzyme expressed in the apical border of proximal tubules. Given the important role of ACE2 in the metabolism of angiotensin II, this study aimed to characterize kidney and urinary ACE2 in a mouse model of AKI. Ischemia-reperfusion injury (IRI) was induced in C57BL/6 mice by clamping of the left renal artery followed by removal of the right kidney. In kidneys harvested 48 h after IRI, immunostaining revealed a striking maldistribution of ACE2 including spillage into the tubular lumen and the presence of ACE2-positive luminal casts in the medulla. In cortical membranes, ACE2 protein and enzymatic activity were both markedly reduced (37 ± 4 vs. 100 ± 6 ACE2/β-actin, P = 0.0004, and 96 ± 14 vs. 152 ± 6 RFU/μg protein/h, P = 0.006). In urine, full-length membrane-bound ACE2 protein (100 kDa) was markedly increased (1,120 ± 405 vs. 100 ± 46 ACE2/µg creatinine, P = 0.04), and casts stained for ACE2 were recovered in the urine sediment. In conclusion, in AKI caused by IRI, there is a marked loss of ACE2 from the apical tubular border with deposition of ACE2-positive material in the medulla and increased urinary excretion of full-length membrane-bound ACE2 protein. The deficiency of tubular ACE2 in AKI suggests that provision of this enzyme could have therapeutic applications and that its excretion in the urine may also serve as a diagnostic marker of severe proximal tubular injury.NEW & NOTEWORTHY This study provides novel insights into the distribution of kidney ACE2 in a model of AKI by IRI showing a striking detachment of apical ACE2 from proximal tubules and its loss in urine and urine sediment. The observed deficiency of kidney ACE2 protein and enzymatic activity in severe AKI suggests that administration of forms of this enzyme may mitigate AKI and that urinary ACE2 may serve as a potential biomarker for tubular injury.
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Affiliation(s)
- Mina Shirazi
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Cosimo Cianfarini
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
- Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ahmed Ismail
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Jan Wysocki
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Jiao-Jing Wang
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Minghao Ye
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Zheng Jenny Zhang
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
| | - Daniel Batlle
- Feinberg School of Medicine, Northwestern University, Chicago, Illinois, United States
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Yamani F, Cianfarini C, Batlle D. Delayed Graft Function and the Renin-angiotensin System. Transplantation 2024; 108:1308-1318. [PMID: 38361243 PMCID: PMC11136607 DOI: 10.1097/tp.0000000000004934] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Delayed graft function (DGF) is a form of acute kidney injury (AKI) and a common complication following kidney transplantation. It adversely influences patient outcomes increases the financial burden of transplantation, and currently, no specific treatments are available. In developing this form of AKI, activation of the renin-angiotensin system (RAS) has been proposed to play an important role. In this review, we discuss the role of RAS activation and its contribution to the pathophysiology of DGF following the different stages of the transplantation process, from procurement and ischemia to transplantation into the recipient and including data from experimental animal models. Deceased kidney donors, whether during cardiac or brain death, may experience activation of the RAS. That may be continued or further potentiated during procurement and organ preservation. Additional evidence suggests that during implantation of the kidney graft and reperfusion in the recipient, the RAS is activated and may likely remain activated, extrapolating from other forms of AKI where RAS overactivity is well documented. Of particular interest in this setting is the status of angiotensin-converting enzyme 2, a key RAS enzyme essential for the metabolism of angiotensin II and abundantly present in the apical border of the proximal tubules, which is the site of predominant injury in AKI and DGF. Interventions aimed at safely downregulating the RAS using suitable shorter forms of angiotensin-converting enzyme 2 could be a way to offer protection against DGF.
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Affiliation(s)
- Fatmah Yamani
- Division of Nephrology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Cosimo Cianfarini
- Division of Nephrology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Daniel Batlle
- Division of Nephrology, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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Karimi F, Nematbakhsh M. Renal vascular responses to angiotensin II infusion in two kidneys-one clip hypertensive rats under partial ischemia/reperfusion with and without ischemia preconditioning: the roles of AT1R blockade and co-blockades of AT1R and MasR. Res Pharm Sci 2023; 18:392-403. [PMID: 37614612 PMCID: PMC10443668 DOI: 10.4103/1735-5362.378086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/14/2023] [Accepted: 05/22/2023] [Indexed: 08/25/2023] Open
Abstract
Background and purpose The renin-angiotensin system activation, partial ischemia/reperfusion (IR) injury, and hypertension contribute to the development of acute kidney injury. The study aims to look at the vascular responses of angiotensin II (Ang II) during Ang II type 1 receptor (AT1R) blockade (losartan) or co-blockades of AT1R and Mas receptor (A779) in two kidneys one clip (2K1C) hypertensive rats which subjected to partial IR injury with and without ischemia preconditioning (IPC). Experimental approach Thirty-three 2K1C male Wistar rats with systolic blood pressure ≥ 150 mmHg were divided into three groups of sham, IR, and IPC + IR divided into two sub-groups receiving losartan or losartan + A779. The IR group had 45 min partial kidney ischemia, while the IPC + IR group had two 5 min cycles of partial ischemia followed by 10 min of reperfusion and then 45 min of partial kidney ischemia followed by reperfusion. The sham group was subjected to similar surgical procedures except for IR or IPC. Findings/Results Ang II increased mean arterial pressure in all the groups, but there were no significant differences between the sub-groups. A significant difference was observed in the renal blood flow response to Ang II between two sub-groups of sham and IR groups treated with AT1R blockade alone or co-blockades of AT1R + A779. Conclusion and implications These findings demonstrated the significance of AT1R and Mas receptor following partial renal IR in the renal blood flow responses to Ang II in 2K1C hypertensive rats.
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Affiliation(s)
- Farzaneh Karimi
- Department of Physiology, Behbahan Faculty of Medical Sciences, Behbahan, Iran
| | - Mehdi Nematbakhsh
- Water & Electrolytes Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
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View of the Renin-Angiotensin System in Acute Kidney Injury Induced by Renal Ischemia-Reperfusion Injury. J Renin Angiotensin Aldosterone Syst 2022; 2022:9800838. [DOI: 10.1155/2022/9800838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 10/06/2022] [Accepted: 10/12/2022] [Indexed: 11/17/2022] Open
Abstract
Renal ischemia-reperfusion injury (RIRI) is a sequence of complicated events that is defined as a reduction of the blood supply followed by reperfusion. RIRI is the leading cause of acute kidney injury (AKI). Among the diverse mediators that take part in RIRI-induced AKI, the renin-angiotensin system (RAS) plays an important role via conventional (angiotensinogen, renin, angiotensin-converting enzyme (ACE), angiotensin (Ang) II, and Ang II type 1 receptor (AT1R)) and nonconventional (ACE2, Ang 1-7, Ang 1-9, AT2 receptor (AT2R), and Mas receptor (MasR)) axes. RIRI alters the balance of both axes so that RAS can affect RIRI-induced AKI. In overall, the alteration of Ang II/AT1R and AKI by RIRI is important to consider. This review has looked for the effects and interactions of RAS activities during RIRI conditions.
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Shawky NM, Dalmasso C, Ojeda NB, Zuchowski Y, Stachenfeld N, Alexander BT, Reckelhoff JF. Consequences of hyperandrogenemia during pregnancy in female offspring: attenuated response to angiotensin II. J Hypertens 2022; 40:712-722. [PMID: 34980865 PMCID: PMC8897268 DOI: 10.1097/hjh.0000000000003067] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND Polycystic ovary syndrome (PCOS) is characterized by reproductive and metabolic dysfunction, and elevated blood pressure (BP). The cardiometabolic consequences of maternal hyperandrogenemia on offspring, either as adults or with aging, have not been well studied. We previously found that male offspring of hyperandrogenemic female (HAF) rats, a model of PCOS, are normotensive but have an exaggerated pressor response to angiotensin (Ang) II. METHOD In this study, the hypothesis was tested that adult and aging female offspring of HAF rats develop a metabolic and hypertensive phenotype. Control and HAF rats were implanted prepubertally with placebo or dihydrotestosterone pellets, which continued throughout pregnancy and lactation. RESULTS Female offspring of HAF dams had lower birth weight than female control offspring. Although female HAF offspring (aged 16-24 weeks) had no differences in intrarenal Ang II, plasma lipids or proteinuria, they did have lower intrarenal Ang (1-7) and lower nitrate/nitrite excretion than controls. Adult HAF offspring had similar baseline BP as controls, but had an attenuated pressor response to Ang II. With aging (16-20 months), female HAF offspring remained normotensive with an attenuated pressor response to Ang II and high salt diet but more proteinuria and higher intrarenal Ang(1-7) than controls. CONCLUSION Taken together, these data suggest that female HAF offspring are protected from developing hypertension, but may be at risk for renal injury with aging. Future studies are necessary to determine whether adult and postmenopausal offspring of PCOS women are at increased risk for cardiovascular dysfunction.Graphical abstract:http://links.lww.com/HJH/B820.
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Affiliation(s)
- Noha M. Shawky
- Departments of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi
- Women’s Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
- Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Carolina Dalmasso
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, Lexington
| | - Norma B. Ojeda
- Pediatrics, University of Mississippi Medical Center, Jackson, Mississippi
- Women’s Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
- Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Yvonne Zuchowski
- Departments of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi
- Women’s Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
- Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Nina Stachenfeld
- The John Pierce Laboratory, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT
| | - Barbara T. Alexander
- Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
- Women’s Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
- Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jane F. Reckelhoff
- Departments of Cell and Molecular Biology, University of Mississippi Medical Center, Jackson, Mississippi
- Women’s Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
- Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, Mississippi
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Freitas F, Attwell D. Pericyte-mediated constriction of renal capillaries evokes no-reflow and kidney injury following ischaemia. eLife 2022; 11:74211. [PMID: 35285797 PMCID: PMC8947765 DOI: 10.7554/elife.74211] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2021] [Accepted: 03/09/2022] [Indexed: 12/12/2022] Open
Abstract
Acute kidney injury is common, with ~13 million cases and 1.7 million deaths/year worldwide. A major cause is renal ischaemia, typically following cardiac surgery, renal transplant or severe haemorrhage. We examined the cause of the sustained reduction in renal blood flow ('no-reflow'), which exacerbates kidney injury even after an initial cause of compromised blood supply is removed. Adult male Sprague-Dawley rats, or NG2-dsRed male mice were used in this study. After 60 min kidney ischaemia and 30-60 min reperfusion, renal blood flow remained reduced, especially in the medulla, and kidney tubule damage was detected as Kim-1 expression. Constriction of the medullary descending vasa recta and cortical peritubular capillaries occurred near pericyte somata, and led to capillary blockages, yet glomerular arterioles and perfusion were unaffected, implying that the long-lasting decrease of renal blood flow contributing to kidney damage was generated by pericytes. Blocking Rho kinase to decrease pericyte contractility from the start of reperfusion increased the post-ischaemic diameter of the descending vasa recta capillaries at pericytes, reduced the percentage of capillaries that remained blocked, increased medullary blood flow and reduced kidney injury. Thus, post-ischaemic renal no-reflow, contributing to acute kidney injury, reflects pericytes constricting the descending vasa recta and peritubular capillaries. Pericytes are therefore an important therapeutic target for treating acute kidney injury.
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Affiliation(s)
- Felipe Freitas
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, United Kingdom
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Angiotensin II type 2 receptor agonist, compound 21, prevents tubular epithelial cell damage caused by renal ischemia. Biochem Pharmacol 2021; 194:114804. [PMID: 34678223 DOI: 10.1016/j.bcp.2021.114804] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2021] [Revised: 10/03/2021] [Accepted: 10/04/2021] [Indexed: 11/20/2022]
Abstract
During ischemic acute kidney injury (AKI), loss of cytoskeletal integrity and disruption of intercellular junctions are rapid events in response to ATP depletion. Angiotensin II type 2 receptor (AT2R) is overexpressed in injury situations and its stimulation by angiotensin II (AngII) is related to beneficial renal effects. Its role on ischemic AKI has not been deeply studied. The aim of the present study was to investigate whether pretreatment with the AT2R agonist, C21, prevents ischemic renal epithelial cell injury. Studies in a model of 40 min of renal ischemia followed by 24 h of reperfusion (IR) in rats demonstrated that C21 pretreatment attenuated renal dysfunction and induced better preservation of tubular architecture. In addition, we studied the expression of Rho GTPases, RhoA and Cdc42, since they are key proteins in the regulation of the actin cytoskeleton and the stability of epithelial intercellular junctions. IR downregulated RhoA and Cdc42 abundance in rat kidneys. C21 pretreatment prevented RhoA reduction and increased Cdc42 abundance compared to controls. We also used an in vitro model of ATP depletion in MDCK cells grown on filter support. Using immunofluorescence we observed that in MDCK cells, C21 pretreatment prevented the ATP depletion-induced reduction of actin in brush border microvilli and in stress fibers. Moreover, C21 prevented membrane E-cadherin reduction, and RhoA and Cdc42 downregulation. The present study describes for the first time a renoprotective effect of the AT2R agonist, C21, against AKI, and provides evidence supporting that stimulation of AT2R triggers cytoprotective mechanisms against an ischemic event.
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Ali R, Patel S, Hussain T. Angiotensin type 2 receptor activation limits kidney injury during the early phase and induces Treg cells during the late phase of renal ischemia. Am J Physiol Renal Physiol 2021; 320:F814-F825. [PMID: 33719572 PMCID: PMC8424555 DOI: 10.1152/ajprenal.00507.2020] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2020] [Revised: 02/12/2021] [Accepted: 03/08/2021] [Indexed: 01/30/2023] Open
Abstract
Kidney infiltrating immune cells such as monocytes, neutrophils, and T cells play critical roles in renal ischemia-reperfusion (IR) injury and repair. Recently, the angiotensin II type 2 receptor (AT2R) has been implicated in protecting kidneys against injury and monocyte infiltration, particularly in chronic kidney disease. However, the role of AT2R in IR injury and repair phases and T cell modulation is unknown. To address this question, Sprague-Dawley rats were subjected to IR with or without AT2R agonist C21 treatment. IR caused early (2 h postreperfusion) renal functional injury (proteinuria, plasma urea, and creatinine) and enhanced immune cells (T cells and CD4 T cells) infiltration and levels of the proinflammatory cytokines monocyte chemoattractant protein-1, TNF-α, and IL-6. C21 treatment reversed these changes but increased the anti-inflammatory IL-10 level. On day 3, C21 treatment increased CD4+FoxP3+ (regulatory T cells) and CD4+IL-10+ cells and reduced kidney injury molecule-1 and neutrophil gelatinase-associated lipocalin in the kidney compared with the IR control, suggesting the involvement of AT2R in kidney repair. These data indicate that AT2R activation protects the kidney against IR injury and immune cell infiltration in the early phase and modulates CD4 T cells toward the regulatory T cell phenotype, which may have long-term beneficial effects on kidney function.NEW & NOTEWORTHY The angiotensin II type 2 receptor agonist C21 has been known to have a renoprotective role in various kidney pathologies. C21 treatment (before renal ischemia) attenuated postischemic kidney injury, kidney dysfunction, and immune cell infiltration during the injury phase. Also, C21 treatment modulated the kidney microenvironment by enhancing anti-inflammatory responses mainly mediated by IL-10. During the repair phase, C21 treatment enhanced IL-10-secreting CD4 T cells and FoxP3-secreting regulatory T cells in Sprague-Dawley rats.
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MESH Headings
- Acute Kidney Injury/immunology
- Acute Kidney Injury/metabolism
- Acute Kidney Injury/pathology
- Acute Kidney Injury/prevention & control
- Animals
- Anti-Inflammatory Agents/pharmacology
- Chemotaxis, Leukocyte/drug effects
- Cytokines/metabolism
- Disease Models, Animal
- Kidney/drug effects
- Kidney/immunology
- Kidney/metabolism
- Kidney/pathology
- Phenotype
- Rats, Sprague-Dawley
- Receptor, Angiotensin, Type 2/agonists
- Receptor, Angiotensin, Type 2/metabolism
- Reperfusion Injury/immunology
- Reperfusion Injury/metabolism
- Reperfusion Injury/pathology
- Reperfusion Injury/prevention & control
- Signal Transduction
- Sulfonamides/pharmacology
- T-Lymphocytes, Regulatory/drug effects
- T-Lymphocytes, Regulatory/immunology
- T-Lymphocytes, Regulatory/metabolism
- Thiophenes/pharmacology
- Time Factors
- Rats
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Affiliation(s)
- Riyasat Ali
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Sanket Patel
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
| | - Tahir Hussain
- Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, Houston, Texas
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Karimi F, Nematbakhsh M. Mas Receptor Blockade Promotes Renal Vascular Response to Ang II after Partial Kidney Ischemia/Reperfusion in a Two-Kidney-One-Clip Hypertensive Rats Model. Int J Nephrol 2021; 2021:6618061. [PMID: 33986960 PMCID: PMC8079216 DOI: 10.1155/2021/6618061] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2020] [Revised: 03/18/2021] [Accepted: 04/12/2021] [Indexed: 12/26/2022] Open
Abstract
BACKGROUND Partial kidney ischemia-reperfusion (IR) injury is the principal cause of acute kidney injury. The renin-angiotensin system (RAS) and hypertension also may be influenced by renal IR injury. In two models of partial renal IR with and without ischemia preconditioning (IPC) and using Mas receptor (MasR) blockade, A779 or its vehicle, the renal vascular responses to angiotensin II (Ang II) administration in two-kidney-one-clip (2K1C) hypertensive rats were determined. METHODS Thirty-seven 2K1C male Wistar rats with systolic blood pressure ≥150 mmHg were randomly divided into three groups; sham, IR, and IPC + IR. The animals in the sham group underwent surgical procedures except partial IR. The rats in the IR group underwent 45 min partial kidney ischemia, and the animals in the IPC + IR group underwent two 5 min cycles of partial kidney ischemia followed by 10 min reperfusion and partial kidney ischemia for 45 min. The renal vascular responses to graded Ang II (30, 100, 300, and 1000 ng kg-1.min-1) infusion using A779 or its vehicle were measured at constant renal perfusion pressure. RESULTS Four weeks after 2K1C implementation, the intravenous infusion of graded Ang II resulted in dose-related increases in mean arterial pressure (MAP) (P dose < 0.0001) that was not different significantly between the groups. No significant differences were detected between the groups in renal blood flow (RBF) or renal vascular resistance (RVR) responses to Ang II infusion when MasR was not blocked. However, by MasR blockade, these responses were increased in IR and IPC + IR groups that were significantly different from the sham group (P < 0.05). For example, infusion of Ang II at dose 1000 ng kg-1.min-1 resulted in decreased RBF percentage change (RBF%) from the baseline to 17.5 ± 1.9%, 39.7 ± 3.8%, and 31.0 ± 3.4% in sham, IR, and IPC + IR, respectively. CONCLUSION These data revealed the important role of MasR after partial kidney IR in the responses of RBF and RVR to Ang II administration in 2K1C hypertensive rats.
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Affiliation(s)
- Farzaneh Karimi
- Water and Electrolytes Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
- Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mehdi Nematbakhsh
- Water and Electrolytes Research Center, Isfahan University of Medical Sciences, Isfahan, Iran
- Department of Physiology, Isfahan University of Medical Sciences, Isfahan, Iran
- Isfahan MN Institute of Basic and Applied Sciences Research, Isfahan, Iran
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11
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Marquez A, Wysocki J, Pandit J, Batlle D. An update on ACE2 amplification and its therapeutic potential. Acta Physiol (Oxf) 2021; 231:e13513. [PMID: 32469114 PMCID: PMC7267104 DOI: 10.1111/apha.13513] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 12/11/2022]
Abstract
The renin angiotensin system (RAS) plays an important role in the pathogenesis of variety of diseases. Targeting the formation and action of angiotensin II (Ang II), the main RAS peptide, has been the key therapeutic target for last three decades. ACE‐related carboxypeptidase (ACE2), a monocarboxypeptidase that had been discovered 20 years ago, is one of the catalytically most potent enzymes known to degrade Ang II to Ang‐(1‐7), a peptide that is increasingly accepted to have organ‐protective properties that oppose and counterbalance those of Ang II. In addition to its role as a RAS enzyme ACE2 is the main receptor for SARS‐CoV‐2. In this review, we discuss various strategies that have been used to achieve amplification of ACE2 activity including the potential therapeutic potential of soluble recombinant ACE2 protein and novel shorter ACE2 variants.
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Affiliation(s)
- Alonso Marquez
- Feinberg Medical SchoolNorthwestern University Chicago IL USA
- Department of Medicine Division of Nephrology and Hypertension Chicago IL USA
| | - Jan Wysocki
- Feinberg Medical SchoolNorthwestern University Chicago IL USA
- Department of Medicine Division of Nephrology and Hypertension Chicago IL USA
| | - Jay Pandit
- Feinberg Medical SchoolNorthwestern University Chicago IL USA
- Department of Medicine Division of Nephrology and Hypertension Chicago IL USA
| | - Daniel Batlle
- Feinberg Medical SchoolNorthwestern University Chicago IL USA
- Department of Medicine Division of Nephrology and Hypertension Chicago IL USA
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12
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Zhao L, Cao X, Li L, Wang Q, Zhou S, Xu N, Jiang S, Chen L, Schmidt MO, Wei Q, Zhao J, Labes R, Patzak A, Wilcox CS, Fu X, Wellstein A, Lai EY. Acute Kidney Injury Sensitizes the Brain Vasculature to Ang II (Angiotensin II) Constriction via FGFBP1 (Fibroblast Growth Factor Binding Protein 1). Hypertension 2020; 76:1924-1934. [PMID: 33040621 PMCID: PMC9112323 DOI: 10.1161/hypertensionaha.120.15582] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 09/14/2020] [Indexed: 12/26/2022]
Abstract
Acute kidney injury (AKI) causes multiple organ dysfunction. Here, we identify a possible mechanism that can drive brain vessel injury after AKI. We induced 30-minute bilateral renal ischemia-reperfusion injury in C57Bl/6 mice and isolated brain microvessels and macrovessels 24 hours or 1 week later to test their responses to vasoconstrictors and found that after AKI brain vessels were sensitized to Ang II (angiotensin II). Upregulation of FGF2 (fibroblast growth factor 2) and FGFBP1 (FGF binding protein 1) expression in both serum and kidney tissue after AKI suggested a potential contribution to the vascular sensitization. Administration of FGF2 and FGFBP1 proteins to isolated healthy brain vessels mimicked the sensitization to Ang II after AKI. Brain vessels in Fgfbp1-/- AKI mice failed to induce Ang II sensitization. Complementary to this, systemic treatment with the clinically used FGF receptor kinase inhibitor BGJ398 (Infigratinib) reversed the AKI-induced brain vascular sensitization to Ang II. All these findings lead to the conclusion that FGFBP1 is especially necessary for AKI-mediated brain vascular sensitization to Ang II and inhibitors of FGFR pathway may be beneficial in preventing AKI-induced brain vessel injury.
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Affiliation(s)
- Liang Zhao
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou 511436, China
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
- Institute of Vegetative Physiology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin 10117, Germany
| | - Xiaoyun Cao
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Lingli Li
- Division of Nephrology and Hypertension, Georgetown University, Washington, DC 20007, USA
| | - Qin Wang
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Suhan Zhou
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Nan Xu
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Shan Jiang
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
| | - Limeng Chen
- Department of Nephrology, Peking Union Medical College Hospital, Chinese Academy of Medical Science & Peking Union Medical College, Beijing 100730, China
| | - Marcel O. Schmidt
- Lombardi Cancer Center, Georgetown University, Washington, DC 20007, USA
| | - Qichun Wei
- Department of Radiation Oncology, Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310009, China
| | - Jingwei Zhao
- Department of Anatomy, Histology and Embryology, Institute of Neuroscience, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Robert Labes
- Institute of Vegetative Physiology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin 10117, Germany
| | - Andreas Patzak
- Institute of Vegetative Physiology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin 10117, Germany
| | - Christopher S. Wilcox
- Division of Nephrology and Hypertension, Georgetown University, Washington, DC 20007, USA
| | - Xiaodong Fu
- Department of Gynecology and Obstetrics, the Sixth Affiliated Hospital, Guangzhou Medical University, Guangzhou 511518, China
| | - Anton Wellstein
- Lombardi Cancer Center, Georgetown University, Washington, DC 20007, USA
| | - En Yin Lai
- Department of Physiology, School of Basic Medical Sciences, Guangzhou Medical University, Guangzhou 511436, China
- Department of Physiology, School of Basic Medical Sciences, Zhejiang University School of Medicine, Hangzhou 310003, China
- Institute of Vegetative Physiology, Charité–Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin 10117, Germany
- Division of Nephrology and Hypertension, Georgetown University, Washington, DC 20007, USA
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13
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Keser H, Bozkurt Girit Ö, Majeed M, Nayak M, Bilgin MD. Pterostilbene administration improves the recovery potential of extremely low-frequency magnetic field in acute renal ischemia-reperfusion injury: an FTIR spectroscopic study. Turk J Biol 2020; 44:48-60. [PMID: 32123495 PMCID: PMC7049455 DOI: 10.3906/biy-1907-18] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Renal ischemia-reperfusion (I/R) injury, one of the drastic outcomes of renal failure and organ transplantation, tends to deteriorate over time; therefore, noninvasive therapeutic strategies will avail the progression-free survival of the patients. Magnetic field has been proposed as a noninvasive treatment strategy; however, with recent scientific advances, many controversies have arisen regarding its efficacy. Pterostilbene, a natural analog of resveratrol, was documented to be effective in treatment of I/R injuries. This study aims to assess the acute therapeutic effects of combined extremely low-frequency magnetic field (ELF-MF) and pterostilbene treatment on renal I/R injury. After induction of renal I/R in Wistar rats, treatments of 50 Hz, 1 mT ELF-MF applied alone or in combination with pterostilbene were applied for 5 consecutive days. Kidney homogenates were analyzed by Fourier transform infrared spectroscopy. I/R injury resulted in an altered protein and lipid structure with the dominance of longer acyl chains; a slight decrease in lipid, protein, unsaturated lipid, and unsaturated/saturated lipid content; and an increase in membrane fluidity and lipid peroxidation in rat kidneys. Although ELF-MF treatment alone was not sufficient to restore all ischemia-induced alterations, the combined treatment strategy of pterostilbene administration in the presence of ELF-MF was successful and warrants further investigation.
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Affiliation(s)
- Hatice Keser
- Department of Biophysics, Institute of Health Sciences, Aydın Adnan Menderes University, Aydın Turkey.,Department of Biophysics, School of Medicine, Karadeniz Technical University, Trabzon Turkey
| | - Özlem Bozkurt Girit
- Department of Biophysics, School of Medicine, Aydın Adnan Menderes University, Aydın Turkey
| | | | - Mahadeva Nayak
- Technical Marketing, Sami Labs Limited, Bangalore, Karnataka India
| | - Mehmet Dinçer Bilgin
- Department of Biophysics, School of Medicine, Aydın Adnan Menderes University, Aydın Turkey
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14
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Wysocki J, Schulze A, Batlle D. Novel Variants of Angiotensin Converting Enzyme-2 of Shorter Molecular Size to Target the Kidney Renin Angiotensin System. Biomolecules 2019; 9:E886. [PMID: 31861139 PMCID: PMC6995632 DOI: 10.3390/biom9120886] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/27/2019] [Accepted: 12/10/2019] [Indexed: 12/29/2022] Open
Abstract
ACE2 is a monocarboxypeptidase which generates Angiotensin (1-7) from Angiotensin II (1-8). Attempts to target the kidney Renin Angiotensin System using native ACE2 to treat kidney disease are hampered by its large molecular size, 100 kDa, which precludes its glomerular filtration and subsequent tubular uptake. Here, we show that both urine and kidney lysates are capable of digesting native ACE2 into shorter proteins of ~60-75 kDa and then demonstrate that they are enzymatically very active. We then truncated the native ACE2 by design from the C-terminus to generate two short recombinant (r)ACE2 variants (1-605 and 1-619AA). These two truncates have a molecular size of ~70 kDa, as expected from the amino acid sequence and as shown by Western blot. ACE2 enzyme activity, measured using a specific substrate, was higher than that of the native rACE2 (1-740 AA). When infused to mice with genetic ACE2 deficiency, a single i.v. injection of 1-619 resulted in detectable ACE2 activity in urine, whereas infusion of the native ACE2 did not. Moreover, ACE2 activity was recovered in harvested kidneys from ACE2-deficient mice infused with 1-619, but not in controls (23.1 ± 4.3 RFU/µg creatinine/h and 1.96 ± 0.73 RFU/µg protein/hr, respectively). In addition, the kidneys of ACE2-null mice infused with 1-619 studied ex vivo formed more Ang (1-7) from exogenous Ang II than those infused with vehicle (AUC 8555 ± 1933 vs. 3439 ± 753 ng/mL, respectively, p < 0.05) further demonstrating the functional effect of increasing kidney ACE2 activity after the infusion of our short ACE2 1-619 variant. We conclude that our novel short recombinant ACE2 variants undergo glomerular filtration, which is associated with kidney uptake of enzymatically active proteins that can enhance the formation of Ang (1-7) from Ang II. These small ACE2 variants may offer a potentially useful approach to target kidney RAS overactivity to combat kidney injury.
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Affiliation(s)
- Jan Wysocki
- Department of Medicine, Division of Nephrology and Hypertension, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA
| | - Arndt Schulze
- Department of Medicine, Division of Nephrology and Hypertension, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA
- Department of Medicine, Charité-Universitätsmedizin, D-10117 Berlin, Germany
| | - Daniel Batlle
- Department of Medicine, Division of Nephrology and Hypertension, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611-3008, USA
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15
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Safari T, Shahraki MR, Miri S, Mirakzehi Bakhshani N, Niazi AA, Komeili GR, Bagheri H. The effect of angiotensin 1-7 and losartan on renal ischemic/reperfusion injury in male rats. Res Pharm Sci 2019; 14:441-447. [PMID: 31798661 PMCID: PMC6827188 DOI: 10.4103/1735-5362.268205] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Ischemia/reperfusion (I/R) is a major cause of acute kidney injury. Several studies have shown that renin angiotensin (Ang) system and activation of Ang II type 1 receptor (AT1) are involved in various forms of kidney diseases. Likewise, Ang 1-7 as a physiologic antagonist of AT1 and losartan could possibly protect the kidney against I/R damage. Therefore, we investigated renal injury by administering the drugs before and after I/R. Fifty-four male Wistar rats were randomly assigned to five groups as follows. 1, Sham operated; 2, saline group (as a control group); 3, losartan group; 4, Ang 1-7group; and 5, Ang 1-7 + losartan simultaneously. It should be noted that groups 2-5 consisted of two separate I/R-induced subgroups both receiving medication where the first groups received the treatment 15 min before induction of I/R while the medications were given to the second groups immediately after induction of I/R. Twenty four h after I/R, blood samples were collected, and then levels of serum urea nitrogen (BUN), creatinine (Cr), nitrite, malondialdehyde (MDA), lactate dehydrogenase (LDH) and total antioxidant capacity (TAC) were measured. Likewise, nitrite, MDA and TAC were measured in the homogenized kidney tissues. After the induction of I/R, the BUN, Cr, LDH, and kidney tissue damage score increased. Administration of Ang 1-7 alone or simultaneously with losartan decreased the levels of aforementioned factors. Also, kidney MDA and nitrate levels significantly increased after I/R induction (P < 0.05). According to the results of this study, it can be claimed that the effect of losartan in the presence of Mas receptor is statistically significant and kidney damage dramatically decreases.
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Affiliation(s)
- Tahereh Safari
- School of Medicine, Department of Physiology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Mohamad Reza Shahraki
- School of Medicine, Department of Physiology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Saideh Miri
- School of Medicine, Department of Physiology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Nasime Mirakzehi Bakhshani
- School of Medicine, Department of Physiology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Abbass Ali Niazi
- School of Medicine, Department of Pathology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Gholam Reza Komeili
- School of Medicine, Department of Physiology, Zahedan University of Medical Sciences, Zahedan, I.R. Iran
| | - Hossain Bagheri
- School of Medicine, Department of Medical English, Zahedan University of Medical Sciences, I.R. Iran
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16
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Soni H, Peixoto-Neves D, Olushoga MA, Adebiyi A. Pharmacological inhibition of TRPV4 channels protects against ischemia-reperfusion-induced renal insufficiency in neonatal pigs. Clin Sci (Lond) 2019; 133:CS20180815. [PMID: 30988131 PMCID: PMC11250923 DOI: 10.1042/cs20180815] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2018] [Revised: 03/27/2019] [Accepted: 04/15/2019] [Indexed: 12/20/2022]
Abstract
Renal vasoconstriction, an early manifestation of ischemic acute kidney injury (AKI), results in renal hypoperfusion and a rapid decline in kidney function. The pathophysiological mechanisms that underlie ischemia-reperfusion (IR)-induced renal insufficiency are poorly understood, but possibilities include alterations in ion channel-dependent renal vasoregulation. In the present study, we show that pharmacological activation of TRPV4 channels constricted preglomerular microvessels and elicited renal hypoperfusion in neonatal pigs. Bilateral renal ischemia followed by short-term reperfusion increased TRPV4 protein expression in resistance size renal vessels and TRPV4-dependent cation currents in renal vascular smooth muscle cells (SMCs). Selective TRPV4 channel blockers attenuated IR-induced reduction in total renal blood flow (RBF), cortical perfusion, and glomerular filtration rate (GFR). TRPV4 inhibition also diminished renal IR-induced increase in AKI biomarkers. Furthermore, the level of angiotensin II (Ang II) was higher in the urine of IR- compared with sham-operated neonatal pigs. IR did not alter renal vascular expression of Ang II type 1 (AT1) receptors. However, losartan, a selective AT1 receptor antagonist, ameliorated IR-induced renal insufficiency in the pigs. Blockade of TRPV4 channels attenuated Ang II-evoked receptor-operated Ca2+ entry and constriction in preglomerular microvessels. TRPV4 inhibition also blunted Ang II-induced increase in renal vascular resistance (RVR) and hypoperfusion in the pigs. Together, our data suggest that SMC TRPV4-mediated renal vasoconstriction and the ensuing increase in RVR contribute to early hypoperfusion and renal insufficiency elicited by renal IR in neonatal pigs. We propose that multimodal signaling by renal vascular SMC TRPV4 channels controls neonatal renal microcirculation in health and disease.
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Affiliation(s)
- Hitesh Soni
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, U.S.A
| | - Dieniffer Peixoto-Neves
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, U.S.A
| | - Michael A Olushoga
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, U.S.A
| | - Adebowale Adebiyi
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, U.S.A.
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17
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Sharma N, Anders HJ, Gaikwad AB. Fiend and friend in the renin angiotensin system: An insight on acute kidney injury. Biomed Pharmacother 2018; 110:764-774. [PMID: 30554115 DOI: 10.1016/j.biopha.2018.12.018] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Revised: 12/05/2018] [Accepted: 12/05/2018] [Indexed: 02/06/2023] Open
Abstract
Besides assisting the maintenance of blood pressure and sodium homeostasis, the renin-angiotensin system (RAS) plays a pivotal role in pathogenesis of acute kidney injury (AKI). The RAS is equipped with two arms i) the pressor arm composed of Angiotensin II (Ang II)/Angiotensin converting enzyme (ACE)/Angiotensin II type 1 receptor (AT1R) also called conventional RAS, and ii) the depressor arm consisting of Angiotensin (1-7) (Ang 1-7)/Angiotensin converting enzyme 2 (ACE2)/MasR known as non-conventional RAS. Activation of conventional RAS triggers oxidative stress, inflammatory, hypertrophic, apoptotic, and pro-fibrotic signaling cascades which promote AKI. The preclinical and clinical studies have reported beneficial as well as deleterious effects of RAS blockage either by angiotensin receptor blocker or ACE inhibitor in AKI. On the contrary, the depressor arm opposes the conventional RAS, has beneficial effects on the kidney but has been less explored in pathogenesis of AKI. This review focuses on significance of RAS in pathogenesis of AKI and provides better understanding of novel and possible therapeutic approaches to combat AKI.
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Affiliation(s)
- Nisha Sharma
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Pilani Campus, Rajasthan 333 031, India
| | - Hans-Joachim Anders
- Division of Nephrology, Department of Internal Medicine IV, University Hospital of the Ludwig Maximilians University Munich, 80336 Munich, Germany
| | - Anil Bhanudas Gaikwad
- Laboratory of Molecular Pharmacology, Department of Pharmacy, Birla Institute of Technology and Science, Pilani, Pilani Campus, Rajasthan 333 031, India.
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18
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Abstract
Tubular injury sensitizes glomeruli to injury. We review potential mechanisms of this tubuloglomerular cross talk. In the same nephron, tubular injury can cause stenosis of the glomerulotubular junction and finally result in atubular glomeruli. Tubular injury also affects glomerular filtration function through tubuloglomerular feedback. Progenitor cells, that is, parietal epithelial cells and renin positive cells, can be involved in repair of injured glomeruli and also may be modulated by tubular injury. Loss of nephrons induces additional workload and stress on remaining nephrons. Hypoxia and activation of the renin-angiotensin-aldosterone system induced by tubular injury also modulate tubuloglomerular cross talk. Therefore, effective therapies in chronic kidney disease may need to aim to interrupt this deleterious tubuloglomerular cross talk.
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Affiliation(s)
- Jiayi Wang
- 1 Division of Nephrology, Second Xiangya Hospital, Central South University, Changsha, China.,2 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Jianyong Zhong
- 2 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,3 Division of Pediatric Nephrology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Hai-Chun Yang
- 2 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,3 Division of Pediatric Nephrology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Agnes B Fogo
- 2 Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA.,3 Division of Pediatric Nephrology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
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19
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Braun D, Dietze S, Pahlitzsch TMJ, Wennysia IC, Persson PB, Ludwig M, Patzak A. Short-term hypoxia and vasa recta function in kidney slices. Clin Hemorheol Microcirc 2018; 67:475-484. [PMID: 28922144 DOI: 10.3233/ch-179230] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND Descending vasa recta (DVR) supply the inner part of outer renal medulla an area at risk for hypoxic damages. OBJECTIVE We hypothesize increased vasoreactivity after hypoxia/re-oxygenation (H/R) in DVR, which might contribute to the reduced medullary perfusion after an ischemic event. METHODS Live kidney slices (200μm) from SD rats were used for functional experiments. TUNEL assay and H&E staining were used to estimate slice viability. Kidney slices were treated with carbogen or hypoxia (1% O2) for 60 or 90 min and vasoreactivity to Ang II (10-7 M) was recorded by DIC microscopy after re-oxygenation with carbogen. Expression of NOS and NADPH enzymes mRNA were determined in iron-perfusion isolated VR. RESULTS Percentage of apoptotic cells increased in control and H/R after 90 min in the medulla. Ang II- induced constriction of DVR was reduced after 90 min in control (compared to 60 min), but not after H/R. NOS enzymes mRNA expression levels decreased over 90 min hypoxia. CONCLUSIONS Increased reactivity of DVR to Ang II after H/R compared to control (90 min) suggest a role of DVR in renal ischemia/reperfusion injury.
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Affiliation(s)
- Diana Braun
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
| | - Stefanie Dietze
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
| | | | - Inggrid C Wennysia
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
| | - Pontus B Persson
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
| | - Marion Ludwig
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
| | - Andreas Patzak
- Institute of Vegetative Physiology, Charité-Universitätsmedizin Berlin, Germany
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20
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Ba Aqeel SH, Sanchez A, Batlle D. Angiotensinogen as a biomarker of acute kidney injury. Clin Kidney J 2017; 10:759-768. [PMID: 29225804 PMCID: PMC5716162 DOI: 10.1093/ckj/sfx087] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Indexed: 02/07/2023] Open
Abstract
Early recognition of acute kidney injury (AKI) is critical to prevent its associated complications as well as its progression to long term adverse outcomes like chronic kidney disease. A growing body of evidence from both laboratory and clinical studies suggests that inflammation is a key factor contributing to the progression of AKI regardless of the initiating event. Biomarkers of inflammation are therefore of interest in the evaluation of AKI pathogenesis and prognosis. There is evidence that the renin angiotensin aldosterone system is activated in AKI, which leads to an increase in angiotensin II (Ang II) formation within the kidney. Ang II activates pro-inflammatory and pro-fibrotic pathways that likely contribute to the progression of AKI. Angiotensinogen is the parent polypeptide from which angiotensin peptides are formed and its stability in urine makes it a more convenient marker of renin angiotensin system activity than direct measurement of Ang II in urine specimens, which would provide more direct information. The potential utility of urinary angiotensinogen as a biomarker of AKI is discussed in light of emerging data showing a strong predictive value of AKI progression, particularly in the setting of decompensated heart failure. The prognostic significance of urinary angiotensinogen as an AKI biomarker strongly suggests a role for renin-angiotensin system activation in modulating the severity of AKI and its outcomes.
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Affiliation(s)
- Sheeba Habeeb Ba Aqeel
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Alejandro Sanchez
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Department of Medicine, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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21
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Cao W, Li A, Li J, Wu C, Cui S, Zhou Z, Liu Y, Wilcox CS, Hou FF. Reno-Cerebral Reflex Activates the Renin-Angiotensin System, Promoting Oxidative Stress and Renal Damage After Ischemia-Reperfusion Injury. Antioxid Redox Signal 2017; 27:415-432. [PMID: 28030955 PMCID: PMC5549812 DOI: 10.1089/ars.2016.6827] [Citation(s) in RCA: 79] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2016] [Revised: 12/19/2016] [Accepted: 12/21/2016] [Indexed: 01/05/2023]
Abstract
AIMS A kidney-brain interaction has been described in acute kidney injury, but the mechanisms are uncertain. Since we recently described a reno-cerebral reflex, we tested the hypothesis that renal ischemia-reperfusion injury (IRI) activates a sympathetic reflex that interlinks the renal and cerebral renin-angiotensin axis to promote oxidative stress and progression of the injury. RESULTS Bilateral ischemia-reperfusion activated the intrarenal and cerebral, but not the circulating, renin-angiotensin system (RAS), increased sympathetic activity in the kidney and the cerebral sympathetic regulatory regions, and induced brain inflammation and kidney injury. Selective renal afferent denervation with capsaicin or renal denervation significantly attenuated IRI-induced activation of central RAS and brain inflammation. Central blockade of RAS or oxidative stress by intracerebroventricular (ICV) losartan or tempol reduced the renal ischemic injury score by 65% or 58%, respectively, and selective renal afferent denervation or reduction of sympathetic tone by ICV clonidine decreased the score by 42% or 52%, respectively (all p < 0.05). Ischemia-reperfusion-induced renal damage and dysfunction persisted after controlling blood pressure with hydralazine. INNOVATION This study uncovered a novel reflex pathway between ischemic kidney and the brain that sustains renal oxidative stress and local RAS activation to promote ongoing renal damage. CONCLUSIONS These data suggest that the renal and cerebral renin-angiotensin axes are interlinked by a reno-cerebral sympathetic reflex that is activated by ischemia-reperfusion, which contributes to ischemia-reperfusion-induced brain inflammation and worsening of the acute renal injury. Antioxid. Redox Signal. 27, 415-432.
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Affiliation(s)
- Wei Cao
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Aiqing Li
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Jiawen Li
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Chunyi Wu
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Shuang Cui
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Zhanmei Zhou
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Youhua Liu
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
| | - Christopher S. Wilcox
- Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia
| | - Fan Fan Hou
- Division of Nephrology, Nanfang Hospital, Southern Medical University, State Key Laboratory of Organ Failure Research, National Clinical Research Center of Kidney Disease, Guangzhou, P.R. China
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22
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Ismail B, deKemp RA, Croteau E, Hadizad T, Burns KD, Beanlands RS, DaSilva JN. Treatment with enalapril and not diltiazem ameliorated progression of chronic kidney disease in rats, and normalized renal AT1 receptor expression as measured with PET imaging. PLoS One 2017; 12:e0177451. [PMID: 28542215 PMCID: PMC5438116 DOI: 10.1371/journal.pone.0177451] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Accepted: 04/27/2017] [Indexed: 12/23/2022] Open
Abstract
ACE inhibitors are considered first line of treatment in patients with many forms of chronic kidney disease (CKD). Other antihypertensives such as calcium channel blockers achieve similar therapeutic effectiveness in attenuating hypertension-related renal damage progression. Our objective was to explore the value of positron emission tomography (PET) imaging of renal AT1 receptor (AT1R) to guide therapy in the 5/6 subtotal-nephrectomy (Nx) rat model of CKD. Ten weeks after Nx, Sprague-Dawley rats were administered 10mg/kg/d enalapril (NxE), 30mg/kg/d diltiazem (NxD) or left untreated (Nx) for an additional 8-10 weeks. Kidney AT1R expression was assessed using in vivo [18F]fluoropyridine-losartan PET and in vitro autoradiography. Compared to shams, Nx rats exhibited higher systolic blood pressure that was reduced by both enalapril and diltiazem. At 18-20 weeks, plasma creatinine and albuminuria were significantly increased in Nx, reduced to sham levels in NxE, but enhanced in NxD rats. Enalapril treatment decreased kidney angiotensin II whereas diltiazem induced significant elevations in plasma and kidney levels. Reduced PET renal AT1R levels in Nx were normalized by enalapril but not diltiazem, and results were supported by autoradiography. Reduction of renal blood flow in Nx was restored by enalapril, while no difference was observed in myocardial blood flow amongst groups. Enhanced left ventricle mass in Nx was not reversed by enalapril but was augmented with diltiazem. Stroke volume was diminished in untreated Nx compared to shams and restored with both therapies. [18F]Fluoropyridine-Losartan PET allowed in vivo quantification of kidney AT1R changes associated with progression of CKD and with various pharmacotherapies.
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Affiliation(s)
- Basma Ismail
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Rob A. deKemp
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Etienne Croteau
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Tayebeh Hadizad
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
| | - Kevin D. Burns
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Kidney Research Centre, Ottawa Hospital Research Institute, University of Ottawa, Ontario, Canada
| | - Rob S. Beanlands
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
| | - Jean N. DaSilva
- Cardiac PET Centre, Department of Medicine (Division of Cardiology), University of Ottawa Heart Institute, Ottawa, ON, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, ON, Canada
- Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal; University of Montreal Hospital Research Centre (CRCHUM), Montréal, Québec, Canada
- * E-mail:
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23
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Maier C, Schadock I, Haber PK, Wysocki J, Ye M, Kanwar Y, Flask CA, Yu X, Hoit BD, Adams GN, Schmaier AH, Bader M, Batlle D. Prolylcarboxypeptidase deficiency is associated with increased blood pressure, glomerular lesions, and cardiac dysfunction independent of altered circulating and cardiac angiotensin II. J Mol Med (Berl) 2017; 95:473-486. [PMID: 28160049 DOI: 10.1007/s00109-017-1513-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 12/20/2016] [Accepted: 01/20/2017] [Indexed: 12/28/2022]
Abstract
Prolylcarboxypeptidase (PRCP) is a carboxypeptidase that cleaves angiotensin II (AngII) forming Ang(1-7). The impact of genetic PRCP deficiency on AngII metabolism, blood pressure (BP), kidney histology, and cardiac phenotype was investigated in two lines of PRCP-deficient mice: KST302 derived in C57BL/6 background and GST090 derived in FVB/N background. The GST090 line had increased mean arterial pressure (MAP) (113.7 ± 2.07 vs. WT 105.0 ± 1.23 mmHg; p < 0.01) and left ventricular hypertrophy (LVH) (ratio of diastolic left ventricular posterior wall dimension to left ventricular diameter 0.239 ± 0.0163 vs. WT 0.193 ± 0.0049; p < 0.05). Mice in the KST302 line also had mild hypertension and LVH. Cardiac defects, increased glomerular size, and glomerular mesangial expansion were also observed. After infusion of AngII to mice in the KST302 line, both MAP and LVH increased, but the constitutive differences between the gene trap mice and controls were no longer observed. Plasma and cardiac AngII and Ang(1-7) were not significantly different between PRCP-deficient mice and controls. Thus, PRCP deficiency is associated with elevated blood pressure and cardiac alterations including LVH and cardiac defects independently of systemic or cardiac AngII and Ang(1-7). An ex vivo assay showed that recombinant PRCP, unlike recombinant ACE2, did not degrade AngII to form Ang(1-7) in plasma at pH 7.4. PRCP was localized in α-intercalated cells of the kidney collecting tubule. The low pH prevailing at this site and the acidic pH preference of PRCP suggest a role of this enzyme in regulating AngII degradation in the collecting tubule where this peptide increases sodium reabsorption and therfore BP. However, there are other potential mechanisms for increased BP in this model that need to be considered as well. PRCP converts AngII to Ang(1-7) but only at an acidic pH. Global PRCP deficiency causes heart and kidney alterations and a moderate rise in BP. PRCP is abundant in the kidney collecting tubules, where the prevailing pH is low. In collecting tubules, PRCP deficiency could result in impaired AngII degradation. Increased AngII at this nephron site stimulates Na reabsorption and increases BP. KEY MESSAGE Prolylcarboxypeptidase (PRCP) converts AngII to Ang (1-7) but only at an acidic pH. Global PRCP deficiency causes heart and kidney alterations and a moderate rise in BP. PRCP is abundant in the kidney collecting tubules, where the prevailing pH is low. In collecting tubules, PRCP deficiency could result in impaired AngII degradation. Increased AngII at this nephron site stimulates Na reabsorption and increases BP.
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Affiliation(s)
- Christoph Maier
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Ines Schadock
- Max Delbrück Center for Molecular Medicine, Berlin, Germany
| | - Philipp K Haber
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.,Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Jan Wysocki
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Minghao Ye
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Yashpal Kanwar
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA
| | - Christopher A Flask
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Xin Yu
- Department of Radiology, Case Western Reserve University, Cleveland, OH, USA.,Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Brian D Hoit
- Department of Medicine, Division of Cardiology, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | - Gregory N Adams
- Department of Medicine, Division of Hematology and Oncology, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | - Alvin H Schmaier
- Department of Medicine, Division of Hematology and Oncology, University Hospitals Case Medical Center and Case Western Reserve University, Cleveland, OH, USA
| | - Michael Bader
- Charité-Universitätsmedizin Berlin, Berlin, Germany.,Max Delbrück Center for Molecular Medicine, Berlin, Germany.,National Institute of Science and Technology in Nanobiopharmaceutics, Federal University of Minas Gerais, Belo Horizonte, Brazil.,German Center for Cardiovascular Research (DZHK), Berlin site, Berlin, Germany
| | - Daniel Batlle
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
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24
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Antenatal corticosteroids and the renin-angiotensin-aldosterone system in adolescents born preterm. Pediatr Res 2017; 81:88-93. [PMID: 27636897 PMCID: PMC5646358 DOI: 10.1038/pr.2016.179] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 07/20/2016] [Indexed: 11/09/2022]
Abstract
BACKGROUND Antenatal corticosteroid (ANCS) treatment hastens fetal lung maturity and improves survival of premature infants, but the long-term effects of ANCS are not well-described. Animal models suggest that ANCS increases the risk of cardiovascular disease through programmed changes in the renin-angiotensin (Ang)-aldosterone system (RAAS). We hypothesized that ANCS exposure alters the RAAS in adolescents born prematurely. METHODS A cohort of 173 adolescents born prematurely was evaluated, of whom 92 were exposed to ANCS. We measured plasma and urine Ang II and Ang-(1-7) and calculated Ang II/Ang-(1-7) ratios. We used general linear regression models to estimate the difference in the RAAS between the ANCS-exposed and unexposed groups, adjusting for confounding variables. RESULTS In unadjusted analyses, and after adjustment for sex, race, and maternal hypertension, ANCS exposure was associated with increased urinary Ang II/Ang-(1-7) (estimate 0.27 (95% CI 0.03, 0.5), P = 0.03), increased plasma Ang-(1-7) (0.66 (0.26, 1.07), P = 0.002), and decreased plasma Ang II/Ang-(1-7) (-0.48 (-0.91, -0.06), P = 0.03). CONCLUSION These alterations indicate an imbalance in the urinary RAAS, promoting the actions of Ang II at the expense of Ang-(1-7), which over time may increase the risk of renal inflammation and fibrosis and ultimately hypertension and renal disease.
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25
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A Primer to Angiotensin Peptide Isolation, Stability, and Analysis by Nano-Liquid Chromatography with Mass Detection. Methods Mol Biol 2017; 1614:175-187. [PMID: 28500604 DOI: 10.1007/978-1-4939-7030-8_14] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The renin-angiotensin system (RAS) is an important element of cardiovascular and renal physiology and targeting the RAS by renin inhibitors, angiotensin (Ang) converting enzyme (ACE) inhibitors and Ang II type 1 receptor antagonists is effective in the treatment of hypertension, heart failure, and atherosclerosis. Quantification of Ang peptides is critical to establish the status of the RAS, but it is challenging due to low Ang peptides concentrations (fmol/mL or fmol/g), abundance of interfering substances, post sampling conversions, and difficulties with the specificity of the assay.In this chapter, we describe a new nano-LC/MS-based methodology for comprehensive, specific, sensitive, and accurate quantification of Ang peptides profile in plasma and tissue. We optimized sample pretreatment method (protein removal (acetonitrile precipitation) followed by solid-phase extraction (C18 silica bonded phase)), chromatographic conditions (reversed-phase nanochromatography with preconcentration), and mass detection (multiple reaction monitoring) of nine peptides: Ang-(1-12), Ang I (1-10), Ang-(1-9), Ang II (1-8), [Ala1]-Ang II, Ang III (2-8), Ang IV (3-8), Ang-(1-7), and [Ala1]-Ang-(1-7). Assessment of plasma and cardiac concentrations of Ang peptides in genetically modified atherosclerotic apolipoprotein E/LDL receptor double knockout (ApoE-/-/LDLR-/-) mice vs. wild types revealed changes in renin-angiotensin system consistent with an overactivation of ACE and impairment of ACE2. The method could be easily adopted for high-throughput analysis and for use in clinical applications such as diagnosis of the RAS abnormalities or monitoring of the RAS inhibition-based therapies.
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26
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Huang Q, Wang Q, Zhang S, Jiang S, Zhao L, Yu L, Hultström M, Patzak A, Li L, Wilcox CS, Lai EY. Increased hydrogen peroxide impairs angiotensin II contractions of afferent arterioles in mice after renal ischaemia-reperfusion injury. Acta Physiol (Oxf) 2016; 218:136-45. [PMID: 27362287 DOI: 10.1111/apha.12745] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 02/15/2016] [Accepted: 06/28/2016] [Indexed: 12/18/2022]
Abstract
AIM Renal ischaemia-reperfusion injury (IRI) increases angiotensin II (Ang II) and reactive oxygen species (ROS) that are potent modulators of vascular function. However, the roles of individual ROS and their interaction with Ang II are not clear. Here we tested the hypothesis that IRI modulates renal afferent arteriolar responses to Ang II via increasing superoxide (O2-) or hydrogen peroxide (H2 O2 ). METHODS Renal afferent arterioles were isolated and perfused from C57BL/6 mice 24 h after IRI or sham surgery. Responses to Ang II or noradrenaline were assessed by measuring arteriolar diameter. Production of H2 O2 and O2- was assessed in afferent arterioles and renal cortex. Activity of SOD and catalase, and mRNA expressions of Ang II receptors were assessed in pre-glomerular arterioles and renal cortex. RESULTS Afferent arterioles from mice after IRI had a reduced maximal contraction to Ang II (-27±2 vs. -42±1%, P < 0.001), but retained a normal contraction to noradrenaline. Arterioles after IRI had a 38% increase in H2 O2 (P < 0.001) and a 45% decrease in catalase activity (P < 0.01). Contractions were reduced in normal arterioles after incubation with H2 O2 (-22±2 vs. -42±1%, P < 0.05) similar to the effects of IRI. However, the impaired contractions were normalized by incubation with PEG catalase despite a reduced AT1 R expression. CONCLUSIONS Renal IRI in mice selectively impairs afferent arteriolar responses to Ang II because of H2 O2 accumulation that is caused by a reduced catalase activity. This could serve to buffer the effect of Ang II after IRI and may be a protective mechanism.
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Affiliation(s)
- Q. Huang
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - Q. Wang
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - S. Zhang
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - S. Jiang
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - L. Zhao
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
| | - L. Yu
- College of Life Sciences; Zhejiang University; Hangzhou China
| | - M. Hultström
- Integrative Physiology; Department of Medical Cell Biology; Uppsala University; Uppsala Sweden
- Anesthesia and Intensive Care Medicine; Department of Surgical Sciences; Uppsala University; Uppsala Sweden
| | - A. Patzak
- Institute of Vegetative Physiology; Charité-Universitätsmedizin Berlin; Berlin Germany
| | - L. Li
- Department of Medicine; Division of Nephrology and Hypertension; Hypertension, Kidney and Vascular Research Center; Georgetown University; Washington DC USA
| | - C. S. Wilcox
- Department of Medicine; Division of Nephrology and Hypertension; Hypertension, Kidney and Vascular Research Center; Georgetown University; Washington DC USA
| | - E. Y. Lai
- Department of Physiology; Zhejiang University School of Medicine; Hangzhou China
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27
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Wysocki J, Batlle D. Urinary Angiotensinogen: A Promising Biomarker of AKI Progression in Acute Decompensated Heart Failure: What Does It Mean? Clin J Am Soc Nephrol 2016; 11:1515-1517. [PMID: 27538427 PMCID: PMC5012482 DOI: 10.2215/cjn.07780716] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Jan Wysocki
- Division of Nephrology and Hypertension, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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28
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Ismail B, deKemp RA, Hadizad T, Mackasey K, Beanlands RS, DaSilva JN. Decreased renal AT1 receptor binding in rats after subtotal nephrectomy: PET study with [(18)F]FPyKYNE-losartan. EJNMMI Res 2016; 6:55. [PMID: 27339045 PMCID: PMC4919198 DOI: 10.1186/s13550-016-0209-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 06/14/2016] [Indexed: 01/13/2023] Open
Abstract
Background Significant renal mass reduction induced by 5/6 subtotal nephrectomy (Nx) is associated with a chain of events that culminates in hypertension and chronic kidney disease (CKD). Numerous studies have provided evidence for the role of angiotensin (Ang) II type 1 receptor (AT1R) in the promotion and progression of the disease; however, conflicting results were reported on intrarenal AT1R levels in CKD models. Methods Male Sprague-Dawley rats (n = 26) underwent Nx or sham operations. Animals were scanned at 8–10 weeks post-surgery with PET using the novel AT1R radioligand [18F]FPyKYNE-losartan. Radioligand binding was quantified by kidney-to-blood ratio (KBR), standard uptake value (SUV), and distribution volume (DV). After sacrifice, plasma and kidney Ang II levels were measured. Western blot and 125I-[Sar1, Ile8]Ang II autoradiography were performed to assess AT1R expression. Results At 8–10 weeks post-surgery, Nx rats developed hypertension, elevated plasma creatinine levels, left ventricle hypertrophy, increased myocardial blood flow (MBF), and reduced Ang II levels compared to shams. PET measurements displayed significant decrease in KBR (29 %), SUV (24 %), and DV (22 %) induced by Nx (p < 0.05), and these findings were confirmed by in vitro assays. Conclusions Reduced renal AT1Rs in hypertensive rats measured with [18F]FPyKYNE-losartan PET at 8–10 weeks following Nx support further use of this non-invasive approach in longitudinal studies to better understand the AT1R role in CKD progression.
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Affiliation(s)
- Basma Ismail
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Robert A deKemp
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Tayebeh Hadizad
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Kumiko Mackasey
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada
| | - Rob S Beanlands
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada
| | - Jean N DaSilva
- National Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON, K1Y 4W7, Canada. .,Department of Cellular and Molecular Medicine, University of Ottawa, 451 Smyth Road, Ottawa, ON, K1H 8M5, Canada. .,Department of Radiology, Radio-Oncology and Nuclear Medicine, University of Montreal, University of Montreal Hospital Research Centre (CRCHUM), 900 Rue Saint-Denis, Montréal, Québec, H2X 0A9, Canada.
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29
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Srisawat U, Kongrat S, Muanprasat C, Chatsudthipong V. Losartan and Sodium Nitroprusside Effectively Protect against Renal Impairments after Ischemia and Reperfusion in Rats. Biol Pharm Bull 2016; 38:753-62. [PMID: 25947921 DOI: 10.1248/bpb.b14-00860] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ischemia and subsequent reperfusion are known to impair renal function. We examined several agents that might prevent renal impairment or enhance the recovery of renal function after ischemia/reperfusion injury in rats. Different degrees of preventive effects were observed in rats treated with captopril, BQ-123 (endothelin type A receptor antagonist), sodium nitroprusside (SNP, a nitric oxide donor), and losartan (angiotensin II type 1 receptor antagonist). Only minimal changes in renal morphology were observed after treatment with losartan, SNP, captopril, and BQ-123 compared with control animals. On the other hand, lesions were prominent in the N(G)-nitro-L-arginine-methyl ester (L-NAME)- and L-arginine-treated rats. The Na(+)-K(+) ATPase activity of ischemic kidneys was, however, preserved in all treatment groups, except in those treated with L-arginine and L-NAME, which showed a marked reduction in Na(+)-K(+) ATPase activity. Our post-treatment data suggest that losartan and SNP have the greatest potential for therapeutic use to mitigate post-ischemic renal damage and functional impairment.
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Affiliation(s)
- Umarat Srisawat
- Department of Physiology, Faculty of Science, Mahidol University
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30
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Bivol LM, Iversen BM, Hultström M, Wallace PW, Reed RK, Wiig H, Tenstad O. Unilateral renal ischaemia in rats induces a rapid secretion of inflammatory markers to renal lymph and increased capillary permeability. J Physiol 2015; 594:1709-26. [PMID: 26584508 DOI: 10.1113/jp271578] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Accepted: 11/11/2015] [Indexed: 12/14/2022] Open
Abstract
A better understanding of the inflammatory process associated with renal ischaemia-reperfusion (IR) injury may be clinically important. In this study we examined the role of the kidney in production of inflammatory mediators by analysing renal lymph after 30 min unilateral occlusion of renal artery followed by 120 min reperfusion, as well as the effect of IR on size selectivity for proteins in both glomerular and peritubular capillaries. All measured mediators increased dramatically in renal hilar lymph, plasma and renal cortical tissue samples and returned to control levels after 120 min reperfusion. The responses were differentiated; interleukin-1β, monocyte chemoattractant protein-1 and leptin were markedly increased in plasma before reperfusion, reflecting an extrarenal response possibly induced by afferent renal nerve activity from the ischaemic kidney. Tumour necrosis factor-α was the only mediator showing elevated lymph-to-plasma ratio following 30 min reperfusion, indicating that most cytokines were released directly into the bloodstream. The IR-induced rise in cytokine levels was paralleled by a significant increase in high molecular weight plasma proteins in both lymph and urine. The latter was shown as a 14- to 166-fold increase in glomerular sieving coefficient of plasma proteins assessed by a novel proteomic approach, and indicated a temporarily reduced size selectivity of both glomerular and peritubular capillaries. Collectively, our data suggest that cytokines from the ischaemic kidney explain most of the rise in plasma concentration, and that the locally produced substances enter the systemic circulation through transport directly to plasma and not via the interstitium to lymph.
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Affiliation(s)
| | - Bjarne Magnus Iversen
- Department of Clinical Science, University of Bergen, Norway.,Haukeland University Hospital, Norway
| | - Michael Hultström
- Department of Clinical Science, University of Bergen, Norway.,Haukeland University Hospital, Norway
| | | | - Rolf Kåre Reed
- Department of Biomedicine, University of Bergen, Norway.,Centre for Cancer Biomarkers (CCBIO), University of Bergen, Norway
| | - Helge Wiig
- Department of Biomedicine, University of Bergen, Norway
| | - Olav Tenstad
- Department of Biomedicine, University of Bergen, Norway
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31
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Ono M, Sakao Y, Tsuji T, Ohashi N, Yasuda H, Nishiyama A, Fujigaki Y, Kato A. Role of intrarenal (pro)renin receptor in ischemic acute kidney injury in rats. Clin Exp Nephrol 2015; 19:185-196. [PMID: 24817138 DOI: 10.1007/s10157-014-0979-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Accepted: 04/27/2014] [Indexed: 11/29/2022]
Abstract
BACKGROUND (Pro)renin receptor [(P)RR], a trans-membrane receptor for renin and prorenin, is involved in the local activation of renin-angiotensin system (RAS) in the kidney. However, it remains to be determined whether (P)RR plays a role in the development of ischemic acute kidney injury (AKI). METHODS We examined the abundance of (P)RR, renin/prorenin, angiotensinogen (AGT), AT1 receptor (AT1R), phosphorylation of extracellular signal-regulated protein kinase 1/2 (ERK 1/2) and nuclear factor-κB (NF-κB) by Western blots at 6, 24 and 48 h, and at 7 days after 45-min ischemic injury in rats. Intrarenal angiotensin II (Ang II) levels were determined by radioimmunoassay. We then tested whether the beneficial effects of oral loading of saline solution (1.0 % NaCl) for 7 days prior to ischemic injury were associated with changes in RAS components and ERK 1/2 and NF-κB phosphorylation in the kidney. We also examined the effect of AT1R blocker, olmesartan, on ischemia-induced changes of (P)RR downstream such as AGT and phosphorylation of ERK 1/2. RESULTS Renal ischemia increased the abundance of (P)RR protein at 24 h, and peaked at 48 h. (P)RR was mainly stained in the connecting tubules and collecting ducts in control rats, while ischemia increased its immunointensity in the damaged proximal tubules. Renal ischemia increased phosphorylation of ERK 1/2 and NF-κB proteins as early as at 6 h. There was a significant increase in AGT and Ang II levels at 24 and 48 h. Prior saline loading prevented the increase in serum creatinine at 48 h (5.36 ± 1.26 vs. 3.38 ± 1.74 mg/dL, p < 0.05), and suppressed the increases in renal (P)RR, AGT and Ang II contents. Saline drinking also significantly blocked the ischemia-induced increases in phosphorylation of ERK 1/2 and NF-κB. In contrast, although treatment with olmesartan (10 mg/kg/day) for 14 days suppressed an increase of intrarenal AGT, olmesartan did not alleviate ischemic AKI, along with no change of (P)RR and phosphorylated ERK 1/2. CONCLUSIONS These findings suggest that increased (P)RR is associated with activation of RAS-independent downstream such as ERK 1/2 and NF-κB phosphorylation in the ischemic kidney.
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Affiliation(s)
- Masafumi Ono
- Internal Medicine 1, Division of Nephrology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu, Shizuoka, 431-3192, Japan,
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32
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Yang X, Chen C, Tian J, Zha Y, Xiong Y, Sun Z, Chen P, Li J, Yang T, Ma C, Liu H, Wang X, Hou FF. Urinary Angiotensinogen Level Predicts AKI in Acute Decompensated Heart Failure: A Prospective, Two-Stage Study. J Am Soc Nephrol 2015; 26:2032-41. [PMID: 25722365 DOI: 10.1681/asn.2014040408] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 09/22/2014] [Indexed: 01/13/2023] Open
Abstract
A major challenge in prevention and early treatment of acute cardiorenal syndrome (CRS) is the lack of high-performance predictors. To test the hypothesis that urinary angiotensinogen (uAGT) is an early predictor for acute CRS and 1-year prognosis in patients with acute decompensated heart failure (ADHF), we performed a prospective, two-stage, multicenter cohort study in patients with ADHF. In stage I (test set), 317 patients were recruited from four centers. In stage II (validation set), 119 patients were enrolled from two other centers. Daily uAGT levels were analyzed consecutively. AKI was defined according to Kidney Disease Improving Global Outcomes (KDIGO) Clinical Practice Guidelines. In stage I, 104 (32.8%) patients developed AKI during hospitalization. Daily uAGT peaked on the first hospital day in patients who subsequently developed AKI. After multivariable adjustment, the highest quartile of uAGT on admission was associated with a 50-fold increased risk of AKI compared with the lowest quartile. For predicting AKI, uAGT (area under the receiver-operating characteristic curve [AUC]=0.84) outperformed urinary neutrophil gelatinase-associated lipocalin (AUC=0.78), the urinary albumin/creatinine ratio (AUC=0.71), and the clinical model (AUC=0.77). Survivors in stage I were followed prospectively for 1 year after hospital discharge. The uAGT level independently predicted the risk of 1-year mortality (adjusted odds ratio, 4.5; 95% confidence interval, 2.1 to 9.5) and rehospitalization (adjusted odds ratio, 3.6; 95% confidence interval, 1.6 to 5.7). The ability of uAGT in predicting AKI was validated in stage II (AUC=0.79). In conclusion, uAGT is a strong predictor for acute CRS and 1-year prognosis in ADHF.
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Affiliation(s)
- Xiaobing Yang
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Chunbo Chen
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China; Guangdong General Hospital, Guangdong Academy of Medical Sciences, Guangdong Cardiovascular Institute, Guangzhou, China
| | - Jianwei Tian
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Yan Zha
- Guizhou Provincial People's Hospital, Guiyang Medical University, Guiyang, China
| | - Yuqin Xiong
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Zhaolin Sun
- Guizhou Provincial People's Hospital, Guiyang Medical University, Guiyang, China
| | - Pingyan Chen
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Jun Li
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China
| | - Tiecheng Yang
- Futian Hospital, Guangdong Medical College, Shenzhen, China
| | - Changsheng Ma
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China; and
| | - Huafeng Liu
- Institute of Nephrology, Guangdong Medical College, Zhanjiang, China; and
| | - Xiaobin Wang
- Center on Early Life Origins of Disease, Johns Hopkins University, Baltimore, Maryland
| | - Fan Fan Hou
- National Clinical Research Center for Kidney Disease, State Key Laboratory of Organ Failure Research, Nanfang Hospital, Southern Medical University, Guangzhou, China;
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Simões e Silva AC, Silveira KD, Ferreira AJ, Teixeira MM. ACE2, angiotensin-(1-7) and Mas receptor axis in inflammation and fibrosis. Br J Pharmacol 2014; 169:477-92. [PMID: 23488800 DOI: 10.1111/bph.12159] [Citation(s) in RCA: 415] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 02/04/2013] [Accepted: 02/13/2013] [Indexed: 12/14/2022] Open
Abstract
Recent advances have improved our understanding of the renin-angiotensin system (RAS). These have included the recognition that angiotensin (Ang)-(1-7) is a biologically active product of the RAS cascade. The identification of the ACE homologue ACE2, which forms Ang-(1-7) from Ang II, and the GPCR Mas as an Ang-(1-7) receptor have provided the necessary biochemical and molecular background and tools to study the biological significance of Ang-(1-7). Most available evidence supports a counter-regulatory role for Ang-(1-7) by opposing many actions of Ang II on AT₁ receptors, especially vasoconstriction and proliferation. Many studies have now shown that Ang-(1-7) by acting via Mas receptor exerts inhibitory effects on inflammation and on vascular and cellular growth mechanisms. Ang-(1-7) has also been shown to reduce key signalling pathways and molecules thought to be relevant for fibrogenesis. Here, we review recent findings related to the function of the ACE2/Ang-(1-7)/Mas axis and focus on the role of this axis in modifying processes associated with acute and chronic inflammation, including leukocyte influx, fibrogenesis and proliferation of certain cell types. More attention will be given to the involvement of the ACE2/Ang-(1-7)/Mas axis in the context of renal disease because of the known relevance of the RAS for the function of this organ and for the regulation of kidney inflammation and fibrosis. Taken together, this knowledge may help in paving the way for the development of novel treatments for chronic inflammatory and renal diseases.
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Affiliation(s)
- A C Simões e Silva
- Departamento de Pediatria, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, Brazil
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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: 227] [Impact Index Per Article: 20.6] [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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Collier SR, Sandberg K, Moody AM, Frechette V, Curry CD, Ji H, Gowdar R, Chaudhuri D, Meucci M. Reduction of plasma aldosterone and arterial stiffness in obese pre- and stage1 hypertensive subjects after aerobic exercise. J Hum Hypertens 2014; 29:53-7. [PMID: 24785976 DOI: 10.1038/jhh.2014.33] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 02/25/2014] [Accepted: 02/28/2014] [Indexed: 01/21/2023]
Abstract
Obesity-related hypertension is associated with increased activity of the renin-angiotensin-aldosterone system (RAAS), increasing arterial stiffness. Aerobic exercise decreases pulse wave velocity (PWV), therefore a treatment option for hypertension and obesity. Assess RAAS activity and PWV before and after 4 weeks of aerobic training in unmedicated, pre-to-stage-1 hypertensives. Ten obese subjects (52±3.2 years, body mass index=33.5±1.4) performed 30 min of aerobic exercise on a treadmill 3 days per week at 65% of peak oxygen consumption (VO2peak). Descriptive characteristics, systolic and diastolic blood pressure (SBP and DBP), PWV, and a blood draw was performed at baseline, following the 4-week control and training interventions. No differences in descriptive characteristics during the control period were observed, however, a significant decrease in plasma aldosterone (ALDO) (255.4±75 to 215.8±66 pg ml(-1), P=0.001), SBP (140±12 to 136±10.4 mm Hg; P=0.02), DBP (89±4.2 to 85±6.3 mm Hg; P=0.03) and central PWV (11.2±0.6 to 9.8±0.8 m s(-1); P=0.04) was shown pre-to-post exercise training. Four weeks of moderate-intensity aerobic training in obese, hypertensives decreases plasma ALDO independently of body weight and is significantly correlated to decreases in PWV reductions.
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Affiliation(s)
- S R Collier
- Vascular Biology and Autonomic Studies Laboratory, Department of Health Leisure and Exercise Science, Appalachian State University, Boone, NC, USA
| | - K Sandberg
- Center for the Study of Sex Differences in Health, Aging and Disease, Department of Medicine, Georgetown University Medical Center, Washington DC, USA
| | - A M Moody
- Vascular Biology and Autonomic Studies Laboratory, Department of Health Leisure and Exercise Science, Appalachian State University, Boone, NC, USA
| | - V Frechette
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA
| | - C D Curry
- Vascular Biology and Autonomic Studies Laboratory, Department of Health Leisure and Exercise Science, Appalachian State University, Boone, NC, USA
| | - H Ji
- Center for the Study of Sex Differences in Health, Aging and Disease, Department of Medicine, Georgetown University Medical Center, Washington DC, USA
| | - R Gowdar
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA
| | - D Chaudhuri
- Department of Medicine, Upstate Medical University, Syracuse, NY, USA
| | - M Meucci
- Department of Movement, University of Rome 'Foro Italico', Human and Health Sciences, Rome, Italy
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Bi J, Contag SA, Carey LC, Tang L, Valego NK, Chappell MC, Rose JC. Antenatal betamethasone exposure alters renal responses to angiotensin-(1-7) in uninephrectomized adult male sheep. J Renin Angiotensin Aldosterone Syst 2013; 14:290-8. [PMID: 23161144 PMCID: PMC4020597 DOI: 10.1177/1470320312465217] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Antenatal corticosteroid exposure reduces renal function and alters the intrarenal renin-angiotensin system to favor angiotensin activation of angiotensin type 1 receptor (AT1R) mediated responses in ovine offspring. This study aimed to assess whether antenatal steroid exposure would affect renal responses to the direct intrarenal infusion of angiotensin-(1-7) in rams and the angiotensin receptors involved in mediating responses to the peptide. Adult, uninephrectomized rams exposed to either betamethasone or vehicle before birth received intrarenal angiotensin-(1-7) infusions (1 ng/kg/min) alone or in combination with antagonists to angiotensin receptors for 3 h. Basal sodium excretion (UNa) was significantly lower and mean arterial pressure was significantly higher in betamethasone- compared to the vehicle-treated sheep. Angiotensin-(1-7) decreased UNa more in betamethasone- than in vehicle-treated sheep. Candesartan reversed the response to angiotensin-(1-7) but D-Ala(7)-angiotensin-(1-7) did not. Angiotensin-(1-7) infusion decreased effective renal plasma flow in both groups to a similar extent and the response was reversed by candesartan, but was not blocked by D-Ala(7)-angiotensin-(1-7). Glomerular filtration rate increased significantly in both groups after 3 h infusion of angiotensin-(1-7) plus candesartan. These results suggest that antenatal exposure to a clinically relevant dose of betamethasone impairs renal function in rams. Moreover, angiotensin-(1-7) appears capable of activating the AT1R in uninephrectomized rams.
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Affiliation(s)
- Jianli Bi
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Stephen A. Contag
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Luke C. Carey
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Lijun Tang
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Nancy K. Valego
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - Mark C. Chappell
- Hypertension and Vascular Disease Center, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
| | - James C. Rose
- Department of Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- Department of Physiology and Pharmacology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
- The Center of Research for Obstetrics and Gynecology, Wake Forest University School of Medicine, Winston-Salem, North Carolina, 27157
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Marshall AC, Shaltout HA, Pirro NT, Rose JC, Diz DI, Chappell MC. Antenatal betamethasone exposure is associated with lower ANG-(1-7) and increased ACE in the CSF of adult sheep. Am J Physiol Regul Integr Comp Physiol 2013; 305:R679-88. [PMID: 23948771 PMCID: PMC3798802 DOI: 10.1152/ajpregu.00321.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Accepted: 08/07/2013] [Indexed: 01/03/2023]
Abstract
Antenatal betamethasone (BM) therapy accelerates lung development in preterm infants but may induce early programming events with long-term cardiovascular consequences. To elucidate these events, we developed a model of programming whereby pregnant ewes are administered BM (2 doses of 0.17 mg/kg) or vehicle at the 80th day of gestation and offspring are delivered at term. BM-exposed (BMX) offspring develop elevated blood pressure; decreased baroreflex sensitivity; and alterations in the circulating, renal, and brain renin-angiotensin systems (RAS) by 6 mo of age. We compared components of the choroid plexus fourth ventricle (ChP4) and cerebral spinal fluid (CSF) RAS between control and BMX male offspring at 6 mo of age. In the choroid plexus, high-molecular-weight renin protein and ANG I-intact angiotensinogen were unchanged between BMX and control animals. Angiotensin-converting enzyme 2 (ACE2) activity was threefold higher than either neprilysin (NEP) or angiotensin 1-converting enzyme (ACE) in control and BMX animals. Moreover, all three enzymes were equally enriched by approximately 2.5-fold in ChP4 brush-border membrane preparations. CSF ANG-(1-7) levels were significantly lower in BMX animals (351.8 ± 76.8 vs. 77.5 ± 29.7 fmol/mg; P < 0.05) and ACE activity was significantly higher (6.6 ± 0.5 vs. 8.9 ± 0.5 fmol·min(-1)·ml(-1); P < 0.05), whereas ACE2 and NEP activities were below measurable limits. A thiol-sensitive peptidase contributed to the majority of ANG-(1-7) metabolism in the CSF, with higher activity in BMX animals. We conclude that in utero BM exposure alters CSF but not ChP RAS components, resulting in lower ANG-(1-7) levels in exposed animals.
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Affiliation(s)
- Allyson C Marshall
- Hypertension and Vascular Research Center, Wake Forest School of Medicine, Winston Salem, North Carolina
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Wang Z, Liu Y, Han Y, Guan W, Kou X, Fu J, Yang D, Ren H, He D, Zhou L, Zeng C. Protective effects of aliskiren on ischemia-reperfusion-induced renal injury in rats. Eur J Pharmacol 2013; 718:160-6. [PMID: 24041923 DOI: 10.1016/j.ejphar.2013.08.038] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Revised: 07/24/2013] [Accepted: 08/27/2013] [Indexed: 01/08/2023]
Abstract
The protective effect of aliskiren on ischemia-reperfusion (I/R) injury in the heart and brain has been reported. Whether or not this protective effect extends into the alleviation of renal I/R injury is not known. Therefore, we investigated the protective effect of aliskiren in the kidney in this study. Sprague-Dawley rats were randomly divided into four groups: sham control group; sham control with aliskiren pretreatment; I/R group and I/R with aliskiren pretreatment. Aliskiren (3mg/kg) or vehicle was administrated intravenously via vena cava. Blood samples and the left kidneys were then collected to check for renal function, angiotensin II (Ang II), apoptosis and oxidative stress levels. Compared with the sham rats, serum creatinine (SCR) and blood urea nitrogen (BUN) were significantly increased in the I/R rats, accompanied by histopathological damage to the kidney, which included tubular cell swelling, desquamation, and cast formation. There were also more apoptotic cells and leukocyte infiltration in the I/R rats than in the sham rats. Pretreatment with aliskiren ameliorated I/R induced renal injury, i.e. reduced SCR and BUN levels, ameliorated renal histopathological changes, and decreased the apoptosis of cells and leukocyte infiltration in kidney. I/R injury also decreased superoxide dismutase (SOD) and glutathione (GSH-reduced form) levels, which were blocked with the aliskiren pretreatment. Aliskiren pretreatment exerts a protective effect on ischemia/reperfusion injury in the kidney, via amelioration of oxidative stress, and reduction in leukocyte infiltration and cellular apoptosis.
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Affiliation(s)
- Zhen Wang
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing 400042, China; Chongqing Institute of Cardiology, Chongqing, China
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Modeling of the renal kinetics of the AT1 receptor specific PET radioligand [11C]KR31173. BIOMED RESEARCH INTERNATIONAL 2013; 2013:835859. [PMID: 24083243 PMCID: PMC3780470 DOI: 10.1155/2013/835859] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/14/2013] [Accepted: 07/17/2013] [Indexed: 11/18/2022]
Abstract
Purpose. The radioligand [11C]KR31173 has been introduced for PET imaging of the angiotensin II subtype 1 receptor (AT1R). The purpose of the present project was to employ and validate a compartmental model for quantification of the kinetics of this radioligand in a porcine model of renal ischemia followed by reperfusion (IR). Procedures. Ten domestic pigs were included in the study: five controls and five experimental animals with IR of the left kidney. To achieve IR, acute ischemia was created with a balloon inserted into the left renal artery and inflated for 60 minutes. Reperfusion was achieved by deflation and removal of the balloon. Blood chemistries, urine specific gravity and PH values, and circulating hormones of the renin angiotensin system were measured and PET imaging was performed one week after IR. Cortical time-activity curves obtained from a 90 min [11C]KR31173 dynamic PET study were processed with a compartmental model that included two tissue compartments connected in parallel. Radioligand binding quantified by radioligand retention (80 min value to maximum value ratio) was compared to the binding parameters derived from the compartmental model. A binding ratio was calculated as DVR = DVS/DVNS, where DVS and DVNS represented the distribution volumes of specific binding and nonspecific binding. Receptor binding was also determined by autoradiography in vitro. Results. Correlations between rate constants and binding parameters derived by the convolution and deconvolution curve fittings were significant (r > 0.9). Also significant was the correlation between the retention parameter derived from the tissue activity curve (Yret) and the retention parameter derived from the impulse response function (fret). Furthermore, significant correlations were found between these two retention parameters and DVR. Measurements with PET showed no significant changes in the radioligand binding parameters caused by IR, and these in vivo findings were confirmed by autoradiography performed in vitro. Conclusions. Correlations between various binding parameters support the concept of the parallel connectivity compartmental model. If an arterial input function cannot be obtained, simple radioligand retention may be adequate for estimation of in vivo radioligand binding.
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Alge JL, Karakala N, Neely BA, Janech MG, Tumlin JA, Chawla LS, Shaw AD, Arthur JM. Association of elevated urinary concentration of renin-angiotensin system components and severe AKI. Clin J Am Soc Nephrol 2013; 8:2043-52. [PMID: 24009222 DOI: 10.2215/cjn.03510413] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
BACKGROUND Prognostic biomarkers that predict the severity of AKI at an early time point are needed. Urinary angiotensinogen was recently identified as a prognostic AKI biomarker. The study hypothesis is that urinary renin could also predict AKI severity and that in combination angiotensinogen and renin would be a strong predictor of prognosis at the time of AKI diagnosis. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS In this multicenter, retrospective cohort study, urine was obtained from 204 patients who developed AKI after cardiac surgery from August 2008 to June 1, 2012. All patients were classified as having Acute Kidney Injury Network (AKIN) stage 1 disease by serum creatinine criteria at the time of sample collection. Urine output was not used for staging. Urinary angiotensinogen and renin were measured, and the area under the receiver-operating characteristic curve (AUC) was used to test for prediction of progression to AKIN stage 3 or in-hospital 30-day mortality. These biomarkers were added stepwise to a clinical model, and improvement in prognostic predictive performance was evaluated by category free net reclassification improvement (cfNRI) and chi-squared automatic interaction detection (CHAID). RESULTS Both the urinary angiotensinogen-to-creatinine ratio (uAnCR; AUC, 0.75; 95% confidence interval [CI], 0.65 to 0.85) and the urinary renin-to-creatinine ratio (uRenCR; AUC, 0.70; 95% CI, 0.57 to 0.83) predicted AKIN stage 3 or death. Addition of uAnCR to a clinical model substantially improved prediction of the outcome (AUC, 0.85; cfNRI, 0.673), augmenting sensitivity and specificity. Further addition of uRenCR increased the sensitivity of the model (cfNRI(events), 0.44). CHAID produced a highly accurate model (AUC, 0.91) and identified the combination of uAnCR >337.89 ng/mg and uRenCR >893.41 pg/mg as the strongest predictors (positive predictive value, 80.4%; negative predictive value, 90.7%; accuracy, 90.2%). CONCLUSION The combination of urinary angiotensinogen and renin predicts progression to very severe disease in patients with early AKI after cardiac surgery.
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Affiliation(s)
- Joseph L Alge
- Medical University of South Carolina, Charleston, South Carolina;, †University of Tennessee College of Medicine in Chattanooga, Chattanooga, Tennessee;, ‡George Washington University, Washington, DC;, §Duke University, Durham, North Carolina;, ‖Durham Veterans Affairs Medical Center, Durham, North Carolina, ¶Ralph H. Johnson Veterans Affairs Medical Center, Charleston, South Carolina
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Fang F, Liu GC, Zhou X, Yang S, Reich HN, Williams V, Hu A, Pan J, Konvalinka A, Oudit GY, Scholey JW, John R. Loss of ACE2 exacerbates murine renal ischemia-reperfusion injury. PLoS One 2013; 8:e71433. [PMID: 23951161 PMCID: PMC3739768 DOI: 10.1371/journal.pone.0071433] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2013] [Accepted: 06/28/2013] [Indexed: 01/28/2023] Open
Abstract
Ischemia-reperfusion (I/R) is a model of acute kidney injury (AKI) that is characterized by vasoconstriction, oxidative stress, apoptosis and inflammation. Previous studies have shown that activation of the renin-angiotensin system (RAS) may contribute to these processes. Angiotensin converting enzyme 2 (ACE2) metabolizes angiotensin II (Ang II) to angiotensin-(1–7), and recent studies support a beneficial role for ACE2 in models of chronic kidney disease. However, the role of ACE2 in models of AKI has not been fully elucidated. In order to test the hypothesis that ACE2 plays a protective role in AKI we assessed I/R injury in wild-type (WT) mice and ACE2 knock-out (ACE2 KO) mice. ACE2 KO and WT mice exhibited similar histologic injury scores and measures of kidney function at 48 hours after reperfusion. Loss of ACE2 was associated with increased neutrophil, macrophage, and T cell infiltration in the kidney. mRNA levels for pro-inflammatory cytokines, interleukin-1β, interleukin-6 and tumour necrosis factor-α, as well as chemokines macrophage inflammatory protein 2 and monocyte chemoattractant protein-1, were increased in ACE2 KO mice compared to WT mice. Changes in inflammatory cell infiltrates and cytokine expression were also associated with greater apoptosis and oxidative stress in ACE2 KO mice compared to WT mice. These data demonstrate a protective effect of ACE2 in I/R AKI.
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Affiliation(s)
- Fei Fang
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - George Chu Liu
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Xiaohua Zhou
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Stuart Yang
- Division of Nephrology, Department of Medicine, University Health Network and University of Toronto, Toronto, Canada
| | - Heather Naomi Reich
- Division of Nephrology, Department of Medicine, University Health Network and University of Toronto, Toronto, Canada
| | - Vanessa Williams
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Amanda Hu
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Janice Pan
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Ana Konvalinka
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
| | - Gavin Yadram Oudit
- Division of Cardiology, Department of Medicine, Mazanlowski Alberta Heart Institute, University of Alberta, Edmonton, Canada
| | - James William Scholey
- Departments of Medicine and Institute of Medical Science, University of Toronto, Toronto, Canada
- Division of Nephrology, Department of Medicine, University Health Network and University of Toronto, Toronto, Canada
| | - Rohan John
- Department of Pathology, University Health Network and University of Toronto, Toronto, Canada
- * E-mail:
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Marshall AC, Shaltout HA, Nautiyal M, Rose JC, Chappell MC, Diz DI. Fetal betamethasone exposure attenuates angiotensin-(1-7)-Mas receptor expression in the dorsal medulla of adult sheep. Peptides 2013; 44:25-31. [PMID: 23538211 PMCID: PMC3690463 DOI: 10.1016/j.peptides.2013.03.018] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 03/13/2013] [Accepted: 03/13/2013] [Indexed: 01/29/2023]
Abstract
Glucocorticoids including betamethasone (BM) are routinely administered to women entering into early preterm labor to facilitate fetal lung development and decrease infant mortality; however, fetal steroid exposure may lead to deleterious long term consequences. In a sheep model of fetal programming, BM-exposed (BMX) offspring exhibit elevated mean arterial pressure (MAP) and decreased baroreflex sensitivity (BRS) for control of heart rate by 0.5-years of age associated with changes in the circulating and renal renin-angiotensin systems (RAS). In the brain solitary tract nucleus, angiotensin (Ang) II actions through the AT1 receptor oppose the beneficial actions of Ang-(1-7) at the Mas receptor for BRS regulation. Therefore, we examined Ang peptides, angiotensinogen (Aogen), and receptor expression in this brain region of exposed and control offspring of 0.5- and 1.8-years of age. Mas protein expression was significantly lower (>40%) in the dorsal medulla of BMX animals at both ages; however, AT1 receptor expression was not changed. BMX offspring exhibited a higher ratio of Ang II to Ang-(1-7) (2.30±0.36 versus 0.99±0.28; p<0.01) and Ang II to Ang I at 0.5-years. Although total Aogen was unchanged, Ang I-intact Aogen was lower in 0.5-year BMX animals (0.78±0.06 vs. 1.94±0.41; p<0.05) suggesting a greater degree of enzymatic processing of the precursor protein in exposed animals. We conclude that in utero BM exposure promotes an imbalance in the central RAS pathways of Ang II and Ang-(1-7) that may contribute to the elevated MAP and lower BRS in this model.
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Affiliation(s)
- Allyson C Marshall
- Hypertension and Vascular Research Center, Wake Forest School of Medicine, Winston Salem, NC, United States
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Alge JL, Karakala N, Neely BA, Janech MG, Velez JCQ, Arthur JM. Urinary angiotensinogen predicts adverse outcomes among acute kidney injury patients in the intensive care unit. CRITICAL CARE : THE OFFICIAL JOURNAL OF THE CRITICAL CARE FORUM 2013; 17:R69. [PMID: 23587112 PMCID: PMC3672721 DOI: 10.1186/cc12612] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Accepted: 04/05/2013] [Indexed: 02/08/2023]
Abstract
INTRODUCTION Acute kidney injury (AKI) is commonly observed in the intensive care unit (ICU), where it can be caused by a variety of factors. The objective of this study was to evaluate the prognostic value of urinary angiotensinogen, a candidate prognostic AKI biomarker identified in post-cardiac surgery patients, in this heterogeneous population. METHODS Urinary angiotensinogen was measured by ELISA and corrected for urine creatinine in 45 patients who developed AKI in the ICU. Patients were grouped by AKI etiology, and the angiotensinogen-to-creatinine ratio (uAnCR) was compared among the groups using the Kruskal-Wallis test. The ability of uAnCR to predict the following endpoints was tested using the area under the ROC curve (AUC): the need for renal replacement therapy (RRT) or death, increased length of stay (defined as hospital discharge>7 days or death≤7 days from sample collection), and worsening AKI (defined as an increase in serum creatinine>0.3 mg/dL after sample collection or RRT). RESULTS uAnCR was significantly elevated in patients who met the composite outcome RRT or death (89.4 vs 25.4 ng/mg; P=0.01), and it was a strong predictor of this outcome (AUC=0.73). Patients with uAnCR values above the median for the cohort (55.21 ng/mg) had increased length of stay compared to patients with uAnCR≤55.21 ng/mg (22 days vs 7 days after sample collection; P=0.01). uAnCR was predictive of the outcome increased length of stay (AUC=0.77). uAnCR was also a strong predictor of worsening of AKI (AUC=0.77). The uAnCR of patients with pre-renal AKI was lower compared to patients with AKI of other causes (median uAnCR 11.3 vs 80.2 ng/mg; P=0.02). CONCLUSIONS Elevated urinary angiotensinogen is associated with adverse events in AKI patients in the ICU. It could be used to identify high risk patients who would benefit from timely intervention that could improve their outcomes.
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Santos RAS, Ferreira AJ, Verano-Braga T, Bader M. Angiotensin-converting enzyme 2, angiotensin-(1-7) and Mas: new players of the renin-angiotensin system. J Endocrinol 2013; 216:R1-R17. [PMID: 23092879 DOI: 10.1530/joe-12-0341] [Citation(s) in RCA: 383] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Angiotensin (Ang)-(1-7) is now recognized as a biologically active component of the renin-angiotensin system (RAS). Ang-(1-7) appears to play a central role in the RAS because it exerts a vast array of actions, many of them opposite to those attributed to the main effector peptide of the RAS, Ang II. The discovery of the Ang-converting enzyme (ACE) homolog ACE2 brought to light an important metabolic pathway responsible for Ang-(1-7) synthesis. This enzyme can form Ang-(1-7) from Ang II or less efficiently through hydrolysis of Ang I to Ang-(1-9) with subsequent Ang-(1-7) formation by ACE. In addition, it is now well established that the G protein-coupled receptor Mas is a functional binding site for Ang-(1-7). Thus, the axis formed by ACE2/Ang-(1-7)/Mas appears to represent an endogenous counterregulatory pathway within the RAS, the actions of which are in opposition to the vasoconstrictor/proliferative arm of the RAS consisting of ACE, Ang II, and AT(1) receptor. In this brief review, we will discuss recent findings related to the biological role of the ACE2/Ang-(1-7)/Mas arm in the cardiovascular and renal systems, as well as in metabolism. In addition, we will highlight the potential interactions of Ang-(1-7) and Mas with AT(1) and AT(2) receptors.
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Affiliation(s)
- Robson A S Santos
- Departments of Physiology and Biophysics Morphology, Biological Sciences Institute, Federal University of Minas Gerais, Belo Horizonte, MG, Brazil
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Alge JL, Karakala N, Neely BA, Janech MG, Tumlin JA, Chawla LS, Shaw AD, Arthur JM. Urinary angiotensinogen and risk of severe AKI. Clin J Am Soc Nephrol 2012; 8:184-93. [PMID: 23143504 DOI: 10.2215/cjn.06280612] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
BACKGROUND Biomarkers of AKI that can predict which patients will develop severe renal disease at the time of diagnosis will facilitate timely intervention in populations at risk of adverse outcomes. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS Liquid chromatography/tandem mass spectrometry was used to identify 30 potential prognostic urinary biomarkers of severe AKI in a group of patients that developed AKI after cardiac surgery. Angiotensinogen had the best discriminative characteristics. Urinary angiotensinogen was subsequently measured by ELISA and its prognostic predictive power was verified in 97 patients who underwent cardiac surgery between August 1, 2008 and October 6, 2011. RESULTS The urine angiotensinogen/creatinine ratio (uAnCR) predicted worsening of AKI, Acute Kidney Injury Network (AKIN) stage 3, need for renal replacement therapy, discharge >7 days from sample collection, and composite outcomes of AKIN stage 2 or 3, AKIN stage 3 or death, and renal replacement therapy or death. The prognostic predictive power of uAnCR was improved when only patients classified as AKIN stage 1 at the time of urine sample collection (n=79) were used in the analysis, among whom it predicted development of stage 3 AKI or death with an area under the curve of 0.81. Finally, category free net reclassification improvement showed that the addition of uAnCR to a clinical model to predict worsening of AKI improved the predictive power. CONCLUSIONS Elevated uAnCR is associated with adverse outcomes in patients with AKI. These data are the first to demonstrate the utility of angiotensinogen as a prognostic biomarker of AKI after cardiac surgery.
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Affiliation(s)
- Joseph L Alge
- Medical University of South Carolina, Charleston, SC 29425, USA
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Schmiedt C, Nelson S, Brainard B, Brown C, Vandenplas M, Hurley D. Bilateral renal ischemia as a model of acute kidney injury in cats. Res Vet Sci 2012; 93:950-9. [DOI: 10.1016/j.rvsc.2011.12.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2011] [Revised: 11/18/2011] [Accepted: 12/07/2011] [Indexed: 10/14/2022]
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Yuen DA, Stead BE, Zhang Y, White KE, Kabir MG, Thai K, Advani SL, Connelly KA, Takano T, Zhu L, Cox AJ, Kelly DJ, Gibson IW, Takahashi T, Harris RC, Advani A. eNOS deficiency predisposes podocytes to injury in diabetes. J Am Soc Nephrol 2012; 23:1810-23. [PMID: 22997257 DOI: 10.1681/asn.2011121170] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Endothelial nitric oxide synthase (eNOS) deficiency may contribute to the pathogenesis of diabetic nephropathy in both experimental models and humans, but the underlying mechanism is not fully understood. Here, we studied two common sequelae of endothelial dysfunction in diabetes: glomerular capillary growth and effects on neighboring podocytes. Streptozotocin-induced diabetes increased glomerular capillary volume in both C57BL/6 and eNOS(-/-) mice. Inhibiting the vascular endothelial growth factor receptor attenuated albuminuria in diabetic C57BL/6 mice but not in diabetic eNOS(-/-) mice, even though it inhibited glomerular capillary enlargement in both. In eNOS(-/-) mice, an acute podocytopathy and heavy albuminuria occurred as early as 2 weeks after inducing diabetes, but treatment with either captopril or losartan prevented these effects. In vitro, serum derived from diabetic eNOS(-/-) mice augmented actin filament rearrangement in cultured podocytes. Furthermore, conditioned medium derived from eNOS(-/-) glomerular endothelial cells exposed to both high glucose and angiotensin II activated podocyte RhoA. Taken together, these results suggest that the combined effects of eNOS deficiency and hyperglycemia contribute to podocyte injury, highlighting the importance of communication between endothelial cells and podocytes in diabetes. Identifying mediators of this communication may lead to the future development of therapies targeting endothelial dysfunction in albuminuric individuals with diabetes.
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Affiliation(s)
- Darren A Yuen
- Keenan Research Centre of the Li Ka Shing Knowledge Institute, St. Michael’s Hospital, Toronto, Ontario, Canada
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Lee TC, Greene-Schloesser D, Payne V, Diz DI, Hsu FC, Kooshki M, Mustafa R, Riddle DR, Zhao W, Chan MD, Robbins ME. Chronic administration of the angiotensin-converting enzyme inhibitor, ramipril, prevents fractionated whole-brain irradiation-induced perirhinal cortex-dependent cognitive impairment. Radiat Res 2012; 178:46-56. [PMID: 22687052 PMCID: PMC3422865 DOI: 10.1667/rr2731.1] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2023]
Abstract
We hypothesized that chronic administration of the angiotensin-converting enzyme inhibitor, ramipril, to young adult male rats would prevent/ameliorate fractionated whole-brain irradiation-induced perirhinal cortex-dependent cognitive impairment. Eighty 12-14-week-old young adult male Fischer 344 rats received either: (1) sham irradiation, (2) 40 Gy of fractionated whole-brain irradiation delivered as two 5 Gy fractions/week for 4 weeks, (3) sham irradiation plus continuous administration of 15 mg/L of ramipril in the drinking water starting 3 days before irradiation, or (4) fractionated whole-brain irradiation plus ramipril. Cognitive function was assessed using a perirhinal cortex-dependent version of the novel object recognition task 26 weeks after irradiation. Microglial activation was determined in the perirhinal cortex and the dentate gyrus of the hippocampus 28 weeks after irradiation using the ED1 antibody. Neurogenesis was assessed in the granular cell layer and subgranular zones of the dentate gyrus using a doublecortin antibody. Fractionated whole-brain irradiation led to: (1) a significant impairment in perirhinal cortex-dependent cognitive function, (2) a significant increase in activated microglia in the dentate gyrus but not in the perirhinal cortex, and (3) a significant decrease in neurogenesis. Continuous administration of ramipril before, during, and after irradiation prevented the fractionated whole-brain irradiation-induced changes in perirhinal cortex-dependent cognitive function, as well as in microglial activation in the dentate gyrus. Thus, as hypothesized, continuous administration of the angiotensin-converting enzyme inhibitor, ramipril, can prevent the fractionated whole-brain irradiation-induced impairment in perirhinal cortex-dependent cognitive function.
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Affiliation(s)
- Tammy C Lee
- Department of Molecular Medicine and Translational Science, Wake Forest School of Medicine, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA
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Yamaleyeva LM, Gilliam-Davis S, Almeida I, Brosnihan KB, Lindsey SH, Chappell MC. Differential regulation of circulating and renal ACE2 and ACE in hypertensive mRen2.Lewis rats with early-onset diabetes. Am J Physiol Renal Physiol 2012; 302:F1374-84. [PMID: 22378820 DOI: 10.1152/ajprenal.00656.2011] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We examined the impact of early diabetes on the circulating and kidney renin-angiotensin system (RAS) in male and female mRen2.Lewis (mRen2) hypertensive rats. Diabetes (DB) was induced by streptozotocin (STZ; 65 mg/kg) at 11 wk of age for 4 wk without insulin replacement. Systolic blood pressures were not increased in DB males or females compared with controls (CON). Circulating angiotensin-converting enzyme 2 (ACE2) increased ninefold (P < 0.05) in DB females and threefold (P < 0.05) in DB males, but circulating ACE and ANG II were higher in the DB groups. Serum C-reactive protein was elevated in DB females but not DB males, and the vascular responses to acetylcholine and estradiol were attenuated in the DB females. Proteinuria, albuminuria, and angiotensinogen excretion increased to a similar extent in both DB females and males. Glomerular VEGF expression also increased to a similar extent in both DB groups. Renal inflammation (CD68(+)cells) increased only in DB females although males exhibited greater inflammation that was not different with DB. Cortical ACE2 did not change in DB females but was reduced (30%) in DB males. Renal neprilysin activity (>75%, P < 0.05) was markedly reduced in the DB females to that in the DB and CON males. ACE activity was significantly lower in both female (75%, P < 0.05) and male (50%; P < 0.05) DB groups, while cortical ANG II and Ang-(1-7) levels were unchanged. In conclusion, female mRen2 rats are not protected from vascular damage, renal inflammation, and kidney injury in early STZ-induced diabetes despite a marked increase in circulating ACE2 and significantly reduced ACE within the kidney.
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Affiliation(s)
- Liliya M Yamaleyeva
- Hypertension and Vascular Research Center, Wake Forest School of Medicine, Medical Center Blvd., Winston-Salem, NC 27157, USA
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Angiotensin converting enzyme 2, Angiotensin-(1-7), and receptor MAS axis in the kidney. Int J Hypertens 2012; 2012:414128. [PMID: 22518283 PMCID: PMC3296191 DOI: 10.1155/2012/414128] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 11/02/2011] [Indexed: 02/07/2023] Open
Abstract
In the past few years the understanding of the renin-angiotensin system (RAS) has improved, helping to better define the role of this system in physiological conditions and in human diseases. Besides Angiotensin (Ang) II, the biological importance of other Ang fragments was progressively evidenced. In this regard, Angiotensin- (Ang-) (1-7) was recognized as a biologically active product of the RAS cascade with a specific receptor, the G-protein-coupled receptor Mas, and that is mainly formed by the action of the angiotensin-converting enzyme (ACE) homolog enzyme, ACE2, which converts Ang II into Ang-(1-7). Taking into account the biological effects of these two mediators, Ang II and Ang-(1-7), the RAS can be envisioned as a dual function system in which the vasoconstrictor/proliferative or vasodilator/antiproliferative actions are primarily driven by the balance between Ang II and Ang-(1-7), respectively. In this paper, we will discuss our current understanding of the ACE2/Ang-(1-7)/Mas axis of the RAS in renal physiology and in the pathogenesis of primary hypertension and chronic kidney disease.
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