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Asadi K, Heidari R, Hamidi M, Ommati MM, Yousefzadeh-Chabok S, Samiraninezhad N, Khoshneviszadeh M, Hashemzaei M, Gholami A. Trinitroglycerin-loaded chitosan nanogels: Shedding light on cytotoxicity, antioxidativity, and antibacterial activities. Int J Biol Macromol 2024; 265:130654. [PMID: 38553395 DOI: 10.1016/j.ijbiomac.2024.130654] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 02/29/2024] [Accepted: 03/04/2024] [Indexed: 04/18/2024]
Abstract
AIM AND BACKGROUND Trinitroglycerin (TNG) is a remarkable NO-releasing agent. Here, we synthesized TNG based on chitosan Nanogels (Ngs) for ameliorating complications associated with high-dose TNG administration. METHOD TNG-Ngs fabricated through ionic-gelation technique. Fourier-transformed infrared (FT-IR), zeta-potential, dynamic light scattering (DLS), and electron microscopy techniques evaluated the physicochemical properties of TNG-Ngs. MTT was used to assess the biocompatibility of TNG-Ngs, as the antioxidative properties were determined via lactate dehydrogenase (LDH), reactive oxygen species (ROS), and lipid peroxide (LPO) assays. The antibacterial activity was evaluated against Staphylococcus aureus (S. aureus), Escherichia coli (E. coli), Methicillin-resistant Staphylococcus aureus (MRSA), and vancomycin-resistant Enterococci (VRE). RESULTS Physicochemical characterization reveals that TNG-Ngs with size diameter (96.2 ± 29 nm), polydispersity index (PDI, 0.732), and negative zeta potential (-1.1 mv) were fabricated. The encapsulation efficacy (EE) and loading capacity (LC) were obtained at 71.1 % and 2.3 %, respectively, with no considerable effect on particle size and morphology. The cytotoxicity assay demonstrated that HepG2 cells exposed to TNG-Ngs showed relative cell viability (RCV) of >80 % for 70 μg/ml compared to the TNG-free drug at the same concentration (P < 0.05). TNG-Ngs showed significant differences with the TNG-free drug for LDH, LPO, and ROS formation at the same concentration (P < 0.001). The antibacterial activity of the TNG-Ngs against S. aureus, E. coli, VRE, and MRSA was higher than the TNG-free drug and Ngs (P < 0.05). CONCLUSION TNG-Ngs with enhanced antibacterial and antioxidative activity and no obvious cytotoxicity might be afforded as novel nanoformulation for promoting NO-dependent diseases.
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Affiliation(s)
- Khatereh Asadi
- Biotechnology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Medical Nanotechnology, School of Advanced Medical Science and Technology, Shiraz University of Medical Sciences, Shiraz, Iran; Guilan Road Trauma Research Center, Guilan University of Medical Sciences, Rasht, Iran
| | - Reza Heidari
- Pharmaceutical Sciences Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Mehrdad Hamidi
- Department of Pharmaceutics, School of Pharmacy, Zanjan University of Medical Sciences, 45139-56184, Zanjan, Iran
| | - Mohammad Mehdi Ommati
- Henan Key Laboratory of Environmental and Animal Product Safety, College of Animal Science and Technology, Henan University of Science and Technology, Luoyang 471000, Henan, China
| | | | | | - Mehdi Khoshneviszadeh
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Masoud Hashemzaei
- Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Ahmad Gholami
- Biotechnology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Medical Nanotechnology, School of Advanced Medical Science and Technology, Shiraz University of Medical Sciences, Shiraz, Iran; Department of Pharmaceutical Biotechnology, School of Pharmacy, Shiraz University of Medical Sciences, Shiraz, Iran.
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Nitric Oxide Signalling in Descending Vasa Recta after Hypoxia/Re-Oxygenation. Int J Mol Sci 2022; 23:ijms23137016. [PMID: 35806018 PMCID: PMC9266395 DOI: 10.3390/ijms23137016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2022] [Revised: 06/20/2022] [Accepted: 06/21/2022] [Indexed: 01/27/2023] Open
Abstract
Reduced renal medullary oxygen supply is a key factor in the pathogenesis of acute kidney injury (AKI). As the medulla exclusively receives blood through descending vasa recta (DVR), dilating these microvessels after AKI may help in renoprotection by restoring renal medullary blood flow. We stimulated the NO-sGC-cGMP signalling pathway in DVR at three different levels before and after hypoxia/re-oxygenation (H/R). Rat DVR were isolated and perfused under isobaric conditions. The phosphodiesterase 5 (PDE5) inhibitor sildenafil (10−6 mol/L) impaired cGMP degradation and dilated DVR pre-constricted with angiotensin II (Ang II, 10−6 mol/L). Dilations by the soluble guanylyl cyclase (sGC) activator BAY 60-2770 as well as the nitric oxide donor sodium nitroprusside (SNP, 10−3 mol/L) were equally effective. Hypoxia (0.1% O2) augmented DVR constriction by Ang II, thus potentially aggravating tissue hypoxia. H/R left DVR unresponsive to sildenafil, yet sGC activation by BAY 60-2770 effectively dilated DVR. Dilation to SNP under H/R is delayed. In conclusion, H/R renders PDE5 inhibition ineffective in dilating the crucial vessels supplying the area at risk for hypoxic damage. Stimulating sGC appears to be the most effective in restoring renal medullary blood flow after H/R and may prove to be the best target for maintaining oxygenation to this vulnerable area of the kidney.
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Tange Y, Watanabe W, Yoshitake S. Nitric oxide delivery using nitric oxide-containing fluid in continuous hemofiltration: an in vitro study. J Artif Organs 2021; 25:66-71. [PMID: 34160716 DOI: 10.1007/s10047-021-01284-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Accepted: 06/16/2021] [Indexed: 11/24/2022]
Abstract
Administering nitrite has therapeutic effects on ischemic conditions wherein the enzymatic production of nitric oxide depends on oxygen. We developed a supplemental fluid containing nitric oxide (NO) and determined the clearance and supply between the pre- and post-dilution modes of continuous hemofiltration in vitro. Nitric oxide gas, 1000 mL or 2000 mL, at a concentration of 1000 ppm, was injected into 2020 mL of conventional supplemental fluid (experimental solution). The same volume of nitrogen gas was injected into the supplemental fluid (control solution). NO concentrations were measured using commercially available NO assay kit. Pre- or post-dilution continuous hemofiltration was performed using a control solution as supplemental fluid to determine the NO clearance. We determined the NO concentration of the outlet blood circuit to confirm the NO supply using the experimental solution as supplemental fluid. Also, using the bovine blood, white blood cell and platelet change rates and the dialysis membrane water flux during continuous hemodiafiltration were evaluated ex vivo as index of the biocompatibilities of a nitric oxide-containing solution. NO was not detected in the control solutions. The experimental solutions significantly increased in nitric oxide concentrations. NO clearance increased as the increase in supplemental and ultrafiltration flow rates using the control solution as supplemental fluid. However, using the experimental solution as supplemental fluid, nitric oxide supply showed a similar trend of NO clearance. Without any changes in biocompatibility using the supplemental fluid containing NO, it could maintain intravascular nitric oxide during continuous renal replacement therapy.
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Affiliation(s)
- Yoshihiro Tange
- Department of Medical Life Sciences, Kyushu University of Health and Welfare, 1714-1 Yoshinomachi, Nobeoka, Miyazaki, Japan.
| | - Wataru Watanabe
- Department of Medical Life Sciences, Kyushu University of Health and Welfare, 1714-1 Yoshinomachi, Nobeoka, Miyazaki, Japan
| | - Shigenori Yoshitake
- Department of Clinical Psychology, Kyushu University of Health and Welfare, 1714-1 Yoshinomachi, Nobeoka, Miyazaki, Japan.
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Kidney physiology and susceptibility to acute kidney injury: implications for renoprotection. Nat Rev Nephrol 2021; 17:335-349. [PMID: 33547418 DOI: 10.1038/s41581-021-00394-7] [Citation(s) in RCA: 124] [Impact Index Per Article: 41.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2021] [Indexed: 01/30/2023]
Abstract
Kidney damage varies according to the primary insult. Different aetiologies of acute kidney injury (AKI), including kidney ischaemia, exposure to nephrotoxins, dehydration or sepsis, are associated with characteristic patterns of damage and changes in gene expression, which can provide insight into the mechanisms that lead to persistent structural and functional damage. Early morphological alterations are driven by a delicate balance between energy demand and oxygen supply, which varies considerably in different regions of the kidney. The functional heterogeneity of the various nephron segments is reflected in their use of different metabolic pathways. AKI is often linked to defects in kidney oxygen supply, and some nephron segments might not be able to shift to anaerobic metabolism under low oxygen conditions or might have remarkably low basal oxygen levels, which enhances their vulnerability to damage. Here, we discuss why specific kidney regions are at particular risk of injury and how this information might help to delineate novel routes for mitigating injury and avoiding permanent damage. We suggest that the physiological heterogeneity of the kidney should be taken into account when exploring novel renoprotective strategies, such as improvement of kidney tissue oxygenation, stimulation of hypoxia signalling pathways and modulation of cellular energy metabolism.
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Cantow K, Ladwig-Wiegard M, Flemming B, Pohlmann A, Niendorf T, Seeliger E. Monitoring Renal Hemodynamics and Oxygenation by Invasive Probes: Experimental Protocol. Methods Mol Biol 2021; 2216:327-347. [PMID: 33476009 PMCID: PMC9703868 DOI: 10.1007/978-1-0716-0978-1_19] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Renal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe methods to study control of renal hemodynamics and tissue oxygenation by means of invasive probes in anesthetized rats. Step-by-step protocols are provided for two setups, one for experiments in laboratories for integrative physiology and the other for experiments within small-animal magnetic resonance scanners.This publication is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This experimental protocol chapter is complemented by a separate chapter describing the basic concepts of quantitatively assessing renal perfusion and oxygenation with invasive probes.
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Affiliation(s)
- Kathleen Cantow
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité - University Medicine Berlin, Berlin, Germany
| | - Mechthild Ladwig-Wiegard
- Institute of Animal Welfare, Animal Behavior and Laboratory Animal Science, Free University Berlin, Berlin, Germany
| | - Bert Flemming
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité - University Medicine Berlin, Berlin, Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany
- Siemens Healthcare, Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany
| | - Erdmann Seeliger
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité - University Medicine Berlin, Berlin, Germany.
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Cantow K, Evans RG, Grosenick D, Gladytz T, Niendorf T, Flemming B, Seeliger E. Quantitative Assessment of Renal Perfusion and Oxygenation by Invasive Probes: Basic Concepts. Methods Mol Biol 2021; 2216:89-107. [PMID: 33475996 PMCID: PMC9703258 DOI: 10.1007/978-1-0716-0978-1_6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/21/2023]
Abstract
Renal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe basic principles of methodology to quantify renal hemodynamics and tissue oxygenation by means of invasive probes in experimental animals. Advantages and disadvantages of the various methods are discussed in the context of the heterogeneity of renal tissue perfusion and oxygenation.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers. This introduction chapter is complemented by a separate chapter describing the experimental procedure and data analysis.
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Affiliation(s)
- Kathleen Cantow
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Australia
| | - Dirk Grosenick
- Physikalisch-Technische Bundesanstalt (German Federal Metrologic Institute), Berlin, Germany
| | - Thomas Gladytz
- Physikalisch-Technische Bundesanstalt (German Federal Metrologic Institute), Berlin, Germany
| | - Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrück Center for Molecular Medicine (MDC) in the Helmholtz Association, Berlin, Germany
| | - Bert Flemming
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Erdmann Seeliger
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany.
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Cantow K, Ladwig-Wiegard M, Flemming B, Fekete A, Hosszu A, Seeliger E. Reversible (Patho)Physiologically Relevant Test Interventions: Rationale and Examples. Methods Mol Biol 2021; 2216:57-73. [PMID: 33475994 DOI: 10.1007/978-1-0716-0978-1_4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Renal tissue hypoperfusion and hypoxia are early key elements in the pathophysiology of acute kidney injury of various origins, and may also promote progression from acute injury to chronic kidney disease. Here we describe test interventions that are used to study the control of renal hemodynamics and oxygenation in experimental animals in the context of kidney-specific control of hemodynamics and oxygenation. The rationale behind the use of the individual tests, the physiological responses of renal hemodynamics and oxygenation, the use in preclinical studies, and the possible application in humans are discussed.This chapter is based upon work from the COST Action PARENCHIMA, a community-driven network funded by the European Cooperation in Science and Technology (COST) program of the European Union, which aims to improve the reproducibility and standardization of renal MRI biomarkers.
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Affiliation(s)
- Kathleen Cantow
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Mechthild Ladwig-Wiegard
- Institute of Animal Welfare, Animal Behavior and Laboratory Animal Science, Free University Berlin, Berlin, Germany
| | - Bert Flemming
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany
| | - Andrea Fekete
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Adam Hosszu
- 1st Department of Pediatrics, Semmelweis University, Budapest, Hungary
| | - Erdmann Seeliger
- Working Group Integrative Kidney Physiology, Institute of Physiology, Charité-University Medicine Berlin, Berlin, Germany.
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Zhang G, Han H, Zhuge Z, Dong F, Jiang S, Wang W, Guimarães DD, Schiffer TA, Lai EY, Ribeiro Antonino Carvalho LR, Lucena RB, Braga VA, Weitzberg E, Lundberg JO, Carlstrom M. Renovascular effects of inorganic nitrate following ischemia-reperfusion of the kidney. Redox Biol 2020; 39:101836. [PMID: 33360353 PMCID: PMC7772560 DOI: 10.1016/j.redox.2020.101836] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 11/29/2020] [Accepted: 12/14/2020] [Indexed: 01/07/2023] Open
Abstract
BACKGROUND Renal ischemia-reperfusion (IR) injury is a common cause of acute kidney injury (AKI), which is associated with oxidative stress and reduced nitric oxide (NO) bioactivity and increased risk of developing chronic kidney disease (CKD) and cardiovascular disease (CVD). New strategies that restore redox balance may have therapeutic implications during AKI and associated complications. AIM To investigate the therapeutic value of boosting the nitrate-nitrite-NO pathway during development of IR-induced renal and cardiovascular dysfunction. METHODS Male C57BL/6 J mice were given sodium nitrate (10 mg/kg, i. p) or vehicle 2 h prior to warm ischemia of the left kidney (45 min) followed by sodium nitrate supplementation in the drinking water (1 mmol/kg/day) for the following 2 weeks. Blood pressure and glomerular filtration rate were measured and blood and kidneys were collected and used for biochemical and histological analyses as well as renal vessel reactivity studies. Glomerular endothelial cells exposed to hypoxia-reoxygenation, with or without angiotensin II, were used for mechanistic studies. RESULTS IR was associated with reduced renal function and slightly elevated blood pressure, in combination with renal injuries, inflammation, endothelial dysfunction, increased Ang II levels and Ang II-mediated vasoreactivity, which were all ameliorated by nitrate. Moreover, treatment with nitrate (in vivo) and nitrite (in vitro) restored NO bioactivity and reduced mitochondrial oxidative stress and injuries. CONCLUSIONS Acute treatment with inorganic nitrate prior to renal ischemia may serve as a novel therapeutic approach to prevent AKI and CKD and associated risk of developing cardiovascular dysfunction.
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Affiliation(s)
- Gensheng Zhang
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Dept. of Neurobiology, Institute of Neuroscience, NHC and CAMS Key Laboratory of Medical Neurobiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Huirong Han
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; Dept. of Anesthesiology, Shandong Provincial Medicine and Health Key Laboratory of Clinical Anesthesia, Weifang Medical University, Weifang, China
| | - Zhengbing Zhuge
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Fang Dong
- Dept. of Physiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Shan Jiang
- Dept. of Physiology, Zhejiang University School of Medicine, Hangzhou, China
| | - Wenwen Wang
- Dept. of Pathology, Women's Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Drielle D Guimarães
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Tomas A Schiffer
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - En Yin Lai
- Dept. of Physiology, Zhejiang University School of Medicine, Hangzhou, China
| | | | | | - Valdir A Braga
- Dept. of Biotechnology - Federal University of Paraiba, Joao Pessoa, PB, Brazil
| | - Eddie Weitzberg
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Jon O Lundberg
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Mattias Carlstrom
- Dept. of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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Amdahl MB, DeMartino AW, Gladwin MT. Inorganic nitrite bioactivation and role in physiological signaling and therapeutics. Biol Chem 2020; 401:201-211. [PMID: 31747370 DOI: 10.1515/hsz-2019-0349] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 11/02/2019] [Indexed: 01/23/2023]
Abstract
The bioactivation of inorganic nitrite refers to the conversion of otherwise 'inert' nitrite to the diatomic signaling molecule nitric oxide (NO), which plays important roles in human physiology and disease, notably in the regulation of vascular tone and blood flow. While the most well-known sources of NO are the nitric oxide synthase (NOS) enzymes, another source of NO is the nitrate-nitrite-NO pathway, whereby nitrite (obtained from reduction of dietary nitrate) is further reduced to form NO. The past few decades have seen extensive study of the mechanisms of NO generation through nitrate and nitrite bioactivation, as well as growing appreciation of the contribution of this pathway to NO signaling in vivo. This review, prepared for the volume 400 celebration issue of Biological Chemistry, summarizes some of the key reactions of the nitrate-nitrite-NO pathway such as reduction, disproportionation, dehydration, and oxidative denitrosylation, as well as current evidence for the contribution of the pathway to human cardiovascular physiology. Finally, ongoing efforts to develop novel medical therapies for multifarious conditions, especially those related to pathologic vasoconstriction and ischemia/reperfusion injury, are also explored.
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Affiliation(s)
- Matthew B Amdahl
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Anthony W DeMartino
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Mark T Gladwin
- Heart, Lung, Blood, and Vascular Medicine Institute, University of Pittsburgh, Pittsburgh, PA 15261, USA.,Division of Pulmonary, Allergy, and Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15213, USA
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Niendorf T, Seeliger E, Cantow K, Flemming B, Waiczies S, Pohlmann A. Probing renal blood volume with magnetic resonance imaging. Acta Physiol (Oxf) 2020; 228:e13435. [PMID: 31876349 DOI: 10.1111/apha.13435] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2019] [Revised: 12/18/2019] [Accepted: 12/19/2019] [Indexed: 02/06/2023]
Abstract
Damage to the kidney substantially reduces life expectancy. Renal tissue hypoperfusion and hypoxia are key elements in the pathophysiology of acute kidney injury and its progression to chronic kidney disease. In vivo assessment of renal haemodynamics and tissue oxygenation remains a challenge. Blood oxygenation level-dependent (BOLD) magnetic resonance imaging (MRI) is sensitive to changes in the effective transversal relaxation time (T2 *) in vivo, and is non-invasive and indicative of renal tissue oxygenation. However, the renal T2 * to tissue pO2 relationship is not governed exclusively by renal blood oxygenation, but is affected by physiological confounders with alterations in renal blood volume fraction (BVf) being of particular relevance. To decipher this interference probing renal BVf is essential for the pursuit of renal MR oximetry. Superparamagnetic iron oxide nanoparticle (USPIO) preparations can be used as MRI visible blood pool markers for detailing alterations in BVf. This review promotes the opportunities of MRI-based assessment of renal BVf. Following an outline on the specifics of renal oxygenation and perfusion, changes in renal BVf upon interventions and their potential impact on renal T2 * are discussed. We also describe the basic principles of renal BVf assessment using ferumoxytol-enhanced MRI in the equilibrium concentration regimen. We demonstrate that ferumoxytol does not alter control of renal haemodynamics and oxygenation. Preclinical applications of ferumoxytol enhanced renal MRI as well as considerations for its clinical implementation for examining renal BVf changes are provided alongside practical considerations. Finally, we explore the future directions of MRI-based assessment of renal BVf.
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Affiliation(s)
- Thoralf Niendorf
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Erdmann Seeliger
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Kathleen Cantow
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Bert Flemming
- Institute of Physiology Charité – Universitätsmedizin Berlin Campus Mitte, and Center for Cardiovascular Research (CCR) Berlin Germany
| | - Sonia Waiczies
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrück Center for Molecular Medicine in the Helmholtz Association Berlin Germany
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Hoff U, Bubalo G, Fechner M, Blum M, Zhu Y, Pohlmann A, Hentschel J, Arakelyan K, Seeliger E, Flemming B, Gürgen D, Rothe M, Niendorf T, Manthati VL, Falck JR, Haase M, Schunck W, Dragun D. A synthetic epoxyeicosatrienoic acid analogue prevents the initiation of ischemic acute kidney injury. Acta Physiol (Oxf) 2019; 227:e13297. [PMID: 31077555 DOI: 10.1111/apha.13297] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022]
Abstract
AIM Imbalances in cytochrome P450 (CYP)-dependent eicosanoid formation may play a central role in ischemic acute kidney injury (AKI). We reported previously that inhibition of 20-hydroxyeicosatetraenoic acid (20-HETE) action ameliorated ischemia/reperfusion (I/R)-induced AKI in rats. Now we tested the hypothesis that enhancement of epoxyeicosatrienoic acid (EET) actions may counteract the detrimental effects of 20-HETE and prevent the initiation of AKI. METHODS Male Lewis rats underwent right nephrectomy and ischemia was induced by 45 min clamping of the left renal pedicle followed by up to 48 h of reperfusion. Circulating CYP-eicosanoid profiles were compared in patients who underwent cardiac surgery with (n = 21) and without (n = 38) developing postoperative AKI. RESULTS Ischemia induced an about eightfold increase of renal 20-HETE levels, whereas free EETs were not accumulated. To compensate for this imbalance, a synthetic 14,15-EET analogue was administered by intrarenal infusion before ischemia. The EET analogue improved renal reoxygenation as monitored by in vivo parametric MRI during the initial 2 h reperfusion phase. The EET analogue improved PI3K- as well as mTORC2-dependent rephosphorylation of Akt, induced inactivation of GSK-3β, reduced the development of tubular apoptosis and attenuated inflammatory cell infiltration. The EET analogue also significantly alleviated the I/R-induced drop in creatinine clearance. Patients developing postoperative AKI featured increased preoperative 20-HETE and 8,9-EET levels. CONCLUSIONS Pharmacological interventions targeting the CYP-eicosanoid pathway could offer promising new options for AKI prevention. Individual differences in CYP-eicosanoid formation may contribute to the risk of developing AKI in clinical settings.
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Affiliation(s)
- Uwe Hoff
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
| | - Gordana Bubalo
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
| | - Mandy Fechner
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
| | | | - Ye Zhu
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
- Department of Nephrology The Fifth Affiliated Hospital of Sun Yat‐sun University Zhuhai China
| | - Andreas Pohlmann
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrueck Center for Molecular Medicine Berlin Germany
| | - Jan Hentschel
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrueck Center for Molecular Medicine Berlin Germany
| | - Karen Arakelyan
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrueck Center for Molecular Medicine Berlin Germany
- Center for Cardiovascular Research, Institute of Physiology Charité‐Universitätsmedizin Berlin Berlin Germany
| | - Erdmann Seeliger
- Center for Cardiovascular Research, Institute of Physiology Charité‐Universitätsmedizin Berlin Berlin Germany
| | - Bert Flemming
- Center for Cardiovascular Research, Institute of Physiology Charité‐Universitätsmedizin Berlin Berlin Germany
| | - Dennis Gürgen
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
| | | | - Thoralf Niendorf
- Max Delbrueck Center for Molecular Medicine Berlin Germany
- Berlin Ultrahigh Field Facility (B.U.F.F.) Max Delbrueck Center for Molecular Medicine Berlin Germany
| | | | - John R. Falck
- Biochemistry Department UT Southwestern Dallas Texas
| | - Michael Haase
- Medical Faculty Otto‐von‐Guericke University Magdeburg Germany
- Diaverum Deutschland Potsdam Germany
| | | | - Duska Dragun
- Nephrology and Intensive Care Medicine, Center for Cardiovascular Research Charité‐Universitätsmedizin Berlin Berlin Germany
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Erdener ŞE, Dalkara T. Small Vessels Are a Big Problem in Neurodegeneration and Neuroprotection. Front Neurol 2019; 10:889. [PMID: 31474933 PMCID: PMC6707104 DOI: 10.3389/fneur.2019.00889] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Accepted: 08/01/2019] [Indexed: 12/11/2022] Open
Abstract
The cerebral microcirculation holds a critical position to match the high metabolic demand by neuronal activity. Functionally, microcirculation is virtually inseparable from other nervous system cells under both physiological and pathological conditions. For successful bench-to-bedside translation of neuroprotection research, the role of microcirculation in acute and chronic neurodegenerative disorders appears to be under-recognized, which may have contributed to clinical trial failures with some neuroprotectants. Increasing data over the last decade suggest that microcirculatory impairments such as endothelial or pericyte dysfunction, morphological irregularities in capillaries or frequent dynamic stalls in blood cell flux resulting in excessive heterogeneity in capillary transit may significantly compromise tissue oxygen availability. We now know that ischemia-induced persistent abnormalities in capillary flow negatively impact restoration of reperfusion after recanalization of occluded cerebral arteries. Similarly, microcirculatory impairments can accompany or even precede neural loss in animal models of several neurodegenerative disorders including Alzheimer's disease. Macrovessels are relatively easy to evaluate with radiological or experimental imaging methods but they cannot faithfully reflect the downstream microcirculatory disturbances, which may be quite heterogeneous across the tissue at microscopic scale and/or happen fast and transiently. The complexity and size of the elements of microcirculation, therefore, require utilization of cutting-edge imaging techniques with high spatiotemporal resolution as well as multidisciplinary team effort to disclose microvascular-neurodegenerative connection and to test treatment approaches to advance the field. Developments in two photon microscopy, ultrafast ultrasound, and optical coherence tomography provide valuable experimental tools to reveal those microscopic events with high resolution. Here, we review the up-to-date advances in understanding of the primary microcirculatory abnormalities that can result in neurodegenerative processes and the combined neurovascular protection approaches that can prevent acute as well as chronic neurodegeneration.
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Affiliation(s)
- Şefik Evren Erdener
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey
| | - Turgay Dalkara
- Institute of Neurological Sciences and Psychiatry, Hacettepe University, Ankara, Turkey.,Department of Neurology, Faculty of Medicine, Hacettepe University, Ankara, Turkey
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Braun D, Zollbrecht C, Dietze S, Schubert R, Golz S, Summer H, Persson PB, Carlström M, Ludwig M, Patzak A. Hypoxia/Reoxygenation of Rat Renal Arteries Impairs Vasorelaxation via Modulation of Endothelium-Independent sGC/cGMP/PKG Signaling. Front Physiol 2018; 9:480. [PMID: 29773995 PMCID: PMC5943512 DOI: 10.3389/fphys.2018.00480] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Accepted: 04/16/2018] [Indexed: 11/13/2022] Open
Abstract
Ischemia/reperfusion injury holds a key position in many pathological conditions such as acute kidney injury and in the transition to chronic stages of renal damage. We hypothesized that besides a reported disproportional activation of vasoconstrictor response, hypoxia/reoxygenation (H/R) adversely affects endothelial dilatory systems and impairs relaxation in renal arteries. Rat renal interlobar arteries were studied under isometric conditions. Hypoxia was induced by application of 95% N2, 5% CO2 for 60 min to the bath solution, followed by a 10 min period of reoxygenation (95% O2, 5% CO2). The effect of H/R on relaxation was assessed using various inhibitors of endothelial dilatory systems. mRNA expression of phosphodiesterase 5 (PDE5), NADPH oxidases (NOX), and nitric oxide synthase (NOS) isoforms were determined using qRT-PCR; cGMP was assayed with direct cGMP ELISA. Acetylcholine induced relaxation was impaired after H/R. Inhibition of the NOS isoforms with L-NAME, and cyclooxygenases (COXs) by indomethacin did not abolish the H/R effect. Moreover, blocking the calcium activated potassium channels KCa3.1 and KCa2.1, the main mediators of the endothelium-derived hyperpolarizing factor, with TRAM34 and UCL1684, respectively, showed similar effects in H/R and control. Arterial stiffness did not differ comparing H/R with controls, indicating no impact of H/R on passive vessel properties. Moreover, superoxide was not responsible for the observed H/R effect. Remarkably, H/R attenuated the endothelium-independent relaxation by sodium nitroprusside, suggesting endothelium-independent mechanisms of H/R action. Investigating the signaling downstream of NO revealed significantly decreased cGMP and impaired relaxation during PDE5 inhibition with sildenafil after H/R. Inhibition of PKG, the target of cGMP, did not normalize SNP-induced relaxation following H/R. However, the soluble guanylyl cyclase (sGC) inhibitor ODQ abolished the H/R effect on relaxation. The mRNA expressions of the endothelial and the inducible NOS were reduced. NOX and PDE5 mRNA were similarly expressed in H/R and control. Our results provide new evidence that impaired renal artery relaxation after H/R is due to a dysregulation of sGC leading to decreased cGMP levels. The presented mechanism might contribute to an insufficient renal reperfusion after ischemia and should be considered in its pathophysiology.
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Affiliation(s)
- Diana Braun
- Renal Vessel Physiology Group, Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Christa Zollbrecht
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Stefanie Dietze
- Renal Vessel Physiology Group, Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Rudolf Schubert
- Centre for Biomedicine and Medical Technology Mannheim, Research Division Cardiovascular Physiology, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | | | | | - Pontus B Persson
- Renal Vessel Physiology Group, Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Mattias Carlström
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden
| | - Marion Ludwig
- Renal Vessel Physiology Group, Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Andreas Patzak
- Renal Vessel Physiology Group, Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany.,Institute of Vegetative Physiology, Charité - Universitätsmedizin Berlin, Berlin, Germany
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