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Fuertes-Kenneally L, Manresa-Rocamora A, Blasco-Peris C, Ribeiro F, Sempere-Ruiz N, Sarabia JM, Climent-Paya V. Effects and Optimal Dose of Exercise on Endothelial Function in Patients with Heart Failure: A Systematic Review and Meta-Analysis. SPORTS MEDICINE - OPEN 2023; 9:8. [PMID: 36739344 PMCID: PMC9899305 DOI: 10.1186/s40798-023-00553-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 01/17/2023] [Indexed: 02/05/2023]
Abstract
BACKGROUND Exercise-based cardiac rehabilitation (CR) is considered an effective treatment for enhancing endothelial function in patients with heart failure (HF). However, recent studies have been published and the optimal "dose" of exercise required to increase the benefits of exercise-based CR programmes on endothelial function is still unknown. OBJECTIVES (a) To estimate the effect of exercise-based CR on endothelial function, assessed by flow-mediated dilation (FMD), in patients with HF; (b) to determine whether high-intensity interval training (HIIT) is better than moderate-intensity training (MIT) for improving FMD; and (c) to investigate the influence of exercise modality (i.e. resistance exercise vs. aerobic exercise and combined exercise vs. aerobic exercise) on the improvement of endothelial function. METHODS Electronic searches were carried out in PubMed, Embase, and Scopus up to February 2022. Random-effects models of between-group mean differences were estimated. Heterogeneity analyses were performed by means of the chi-square test and I2 index. Subgroup analyses and meta-regressions were used to test the influence of potential moderator variables on the effect of exercise. RESULTS We found a FMD increase of 3.09% (95% confidence interval [CI] = 2.01, 4.17) in favour of aerobic-based CR programmes compared with control groups in patients with HF and reduced ejection fraction (HFrEF). However, the results of included studies were inconsistent (p < .001; I2 = 95.2%). Higher FMD improvement was found in studies which were randomised, reported radial FMD, or performed higher number of training sessions a week. Moreover, HIIT enhanced FMD to a greater extent than MIT (2.35% [95% CI = 0.49, 4.22]) in patients with HFrEF. Insufficient data prevented pooled analyses for the effect of exercise in patients with HF and preserved ejection fraction and the influence of exercise modality on the improvement of endothelial function. CONCLUSION Aerobic-based CR is a non-pharmacological treatment for enhancing endothelial function in patients with HFrEF. However, higher training frequency and HIIT induce greater adaptation of endothelial function in these patients, which should betaken into consideration when designing exercise-based CR programmes. Trial registration The protocol was prospectively registered on the PROSPERO database (CRD42022304687).
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Affiliation(s)
- Laura Fuertes-Kenneally
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,Cardiology Department, Alicante General University Hospital (HGUA), 03010 Alicante, Spain
| | - Agustín Manresa-Rocamora
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,grid.26811.3c0000 0001 0586 4893Department of Sport Sciences, Sports Research Centre, Miguel Hernández University of Elche, 03202 Elche, Spain
| | - Carles Blasco-Peris
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,grid.5338.d0000 0001 2173 938XDepartment of Physical Education and Sport, University of Valencia, 46010 Valencia, Spain
| | - Fernando Ribeiro
- grid.7311.40000000123236065Institute of Biomedicine‑iBiMED and School of Health Sciences, University of Aveiro, 3810-193 Aveiro, Portugal
| | - Noemí Sempere-Ruiz
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,grid.26811.3c0000 0001 0586 4893Department of Sport Sciences, Sports Research Centre, Miguel Hernández University of Elche, 03202 Elche, Spain
| | - José Manuel Sarabia
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,grid.26811.3c0000 0001 0586 4893Department of Sport Sciences, Sports Research Centre, Miguel Hernández University of Elche, 03202 Elche, Spain
| | - Vicente Climent-Paya
- grid.513062.30000 0004 8516 8274Institute for Health and Biomedical Research of Alicante (ISABIAL), 03010 Alicante, Spain ,Cardiology Department, Alicante General University Hospital (HGUA), 03010 Alicante, Spain
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Meariman JK, Zulli H, Perez A, Bajracharya S, Mohandas R. Small vessel disease: Connections between the kidney and the heart. AMERICAN HEART JOURNAL PLUS : CARDIOLOGY RESEARCH AND PRACTICE 2023; 26:100257. [PMID: 38510186 PMCID: PMC10946057 DOI: 10.1016/j.ahjo.2023.100257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Revised: 01/10/2023] [Accepted: 01/13/2023] [Indexed: 03/22/2024]
Abstract
Small vessel disease is characterized by global dysfunction of the microvascular system leading to reduced perfusion of various organ systems. The kidney is significantly vulnerable for microvascular dysfunction given its intricate capillary network and extensive endocrine influence. Studies have demonstrated a relationship between impaired renal function and small vessel disease in other organ systems, particularly the heart. Here we discuss the relationship between the kidney and the heart in the setting of microvascular dysfunction and identify areas of future study to better understand this relationship and potentially identify novel therapeutic strategies.
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Affiliation(s)
- Jacob K. Meariman
- Section of Nephrology & Hypertension, Department of Medicine, LSU Health New Orleans School of Medicine, New Orleans, LA 70112, United States of America
| | - Hannah Zulli
- Section of Nephrology & Hypertension, Department of Medicine, LSU Health New Orleans School of Medicine, New Orleans, LA 70112, United States of America
| | - Annalisa Perez
- Section of Nephrology & Hypertension, Department of Medicine, LSU Health New Orleans School of Medicine, New Orleans, LA 70112, United States of America
| | - S.D. Bajracharya
- Section of Nephrology & Hypertension, Department of Medicine, LSU Health New Orleans School of Medicine, New Orleans, LA 70112, United States of America
| | - Rajesh Mohandas
- Section of Nephrology & Hypertension, Department of Medicine, LSU Health New Orleans School of Medicine, New Orleans, LA 70112, United States of America
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Tong KL, Tan KE, Lim YY, Tien XY, Wong PF. CircRNA-miRNA interactions in atherogenesis. Mol Cell Biochem 2022; 477:2703-2733. [PMID: 35604519 DOI: 10.1007/s11010-022-04455-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 04/27/2022] [Indexed: 11/30/2022]
Abstract
Atherosclerosis is the major cause of coronary artery disease (CAD) which includes unstable angina, myocardial infarction, and heart failure. The onset of atherogenesis, a process of atherosclerotic lesion formation in the intima of arteries, is driven by lipid accumulation, a vicious cycle of reactive oxygen species (ROS)-induced oxidative stress and inflammatory reactions leading to endothelial cell (EC) dysfunction, vascular smooth muscle cell (VSMC) activation, and foam cell formation which further fuel plaque formation and destabilization. In recent years, there is a surge in the number of publications reporting the involvement of circular RNAs (circRNAs) in the pathogenesis of cardiovascular diseases, cancers, and metabolic syndromes. These studies have advanced our understanding on the biological functions of circRNAs. One of the most common mechanism of action of circRNAs reported is the sponging of microRNAs (miRNAs) by binding to the miRNAs response element (MRE), thereby indirectly increases the transcription of their target messenger RNAs (mRNAs). Individual networks of circRNA-miRNA-mRNA associated with atherogenesis have been extensively reported, however, there is a need to connect these findings for a complete overview. This review aims to provide an update on atherogenesis-related circRNAs and analyze the circRNA-miRNA-mRNA interactions in atherogenesis. The atherogenic mechanisms and clinical relevance of each atherogenesis-related circRNA were systematically discussed for better understanding of the knowledge gap in this area.
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Affiliation(s)
- Kind-Leng Tong
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Ke-En Tan
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Yat-Yuen Lim
- Institute of Biological Sciences, Faculty of Science, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Xin-Yi Tien
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia
| | - Pooi-Fong Wong
- Department of Pharmacology, Faculty of Medicine, Universiti Malaya, 50603, Kuala Lumpur, Malaysia.
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Shimada S, Yang C, Kurth T, Cowley AW. Divergent roles of angiotensin II upon the immediate and sustained increases of renal blood flow following unilateral nephrectomy. Am J Physiol Renal Physiol 2022; 322:F473-F485. [PMID: 35224992 PMCID: PMC8977133 DOI: 10.1152/ajprenal.00376.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/31/2022] [Accepted: 02/18/2022] [Indexed: 12/18/2022] Open
Abstract
Although the molecular and functional responses related to renal compensatory hypertrophy after unilateral nephrectomy (UNX) has been well described, many aspects of these events remain unclear. One question is how the remaining kidney senses the absence of the contralateral organ, and another is what the role of the renin-angiotensin system is in these responses. Both acute anesthetized and chronic unanesthetized experiments were performed using the angiotensin II type 1 receptor blocker losartan and the renin inhibitor aliskiren to determine the contribution of the renin-angiotensin system to immediate changes and losartan for chronic changes of renal blood flow (RBF) and the associated hypertrophic events in male Sprague-Dawley rats. Chronic experiments used implanted RBF probes and arterial catheters for continuous data collection, and the glomerular filtration rate was determined by noninvasive transcutaneous FITC-sinistrin measurements. The results of the acute experiments found that RBF increased nearly 25% (4.6 ± 0.5 to 5.6 ± 0.6 mL/min/g kidney wt) during the first 15 min following UNX and that this response was abolished by losartan (6.7 ± 0.7 to 7.0 ± 0.7 mL/min/g kidney wt) or aliskiren (5.8 ± 0.4 to 6.0 ± 0.4 mL/min/g kidney wt) treatment. Thereafter, RBF increased progressively over 7 days, and kidney weight increased by 19% of pre-UNX values. When normalized to kidney weight determined at day 7 after UNX, RBF was not significantly different from pre-UNX levels. Semiquantification of CD31-positive capillaries revealed increases of the glomeruli and peritubular capillaries that paralleled the kidney hypertrophy. None of these chronic changes was inhibited by losartan treatment, indicating that neither the compensatory structural nor the RBF changes were angiotensin II type 1 receptor dependent.NEW & NOTEWORTHY This study found that the immediate increases of renal blood flow (RBF) following unilateral nephrectomy (UNX) are a consequence of reduced angiotensin II type 1 (AT1) receptor stimulation. The continuous monitoring of RBF and intermittent measurement of glomerular filtration rate (GFR) in conscious rats during the 1-wk period of rapid hypertrophy following UNX provided unique insights into the regulation of RBF and GFR when faced with increased metabolic loads. It was found that neither kidney hypertrophy nor the associated increase of capillaries was an AT1-dependent phenomenon.
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Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Krishnan S, Suarez-Martinez AD, Bagher P, Gonzalez A, Liu R, Murfee WL, Mohandas R. Microvascular dysfunction and kidney disease: Challenges and opportunities? Microcirculation 2021; 28:e12661. [PMID: 33025626 PMCID: PMC9990864 DOI: 10.1111/micc.12661] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 09/18/2020] [Accepted: 09/29/2020] [Indexed: 12/29/2022]
Abstract
Kidneys are highly vascular organs that despite their relatively small size receive 20% of the cardiac output. The highly intricate, delicately organized structure of renal microcirculation is essential to enable renal function and glomerular filtration rate through the local modulation of renal blood flow and intraglomerular pressure. Not surprisingly, the dysregulation of blood flow within the microvessels (abnormal vasoreactivity), fibrosis driven by disordered vascular-renal cross talk, or the loss of renal microvasculature (rarefaction) is associated with kidney disease. In addition, kidney disease can cause microcirculatory dysfunction in distant organs such as the heart and brain, mediated by mechanisms that remain to be elucidated. The objective of this review is to highlight the role of renal microvasculature in kidney disease. The overview will outline the impetus to study renal microvasculature, the bidirectional relationship between kidney disease and microvascular dysfunction, the key pathways driving microvascular diseases such as vasoreactivity, the cell dynamics coordinating fibrosis, and vessel rarefaction. Finally, we will also briefly highlight new therapies targeting the renal microvasculature to improve renal function.
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Affiliation(s)
- Suraj Krishnan
- Division of Nephrology, Hypertension & Transplantation, University of Florida College of Medicine, Gainesville, FL, USA
| | - Ariana D Suarez-Martinez
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Pooneh Bagher
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, TX, USA
| | - Anjelica Gonzalez
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Ruisheng Liu
- Department of Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, FL, USA
| | - Walter L Murfee
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, FL, USA
| | - Rajesh Mohandas
- Division of Nephrology, Hypertension & Transplantation, University of Florida College of Medicine, Gainesville, FL, USA
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Abstract
The prevalence of cardiovascular and metabolic disease coupled with kidney dysfunction is increasing worldwide. This triad of disorders is associated with considerable morbidity and mortality as well as a substantial economic burden. Further understanding of the underlying pathophysiological mechanisms is important to develop novel preventive or therapeutic approaches. Among the proposed mechanisms, compromised nitric oxide (NO) bioactivity associated with oxidative stress is considered to be important. NO is a short-lived diatomic signalling molecule that exerts numerous effects on the kidneys, heart and vasculature as well as on peripheral metabolically active organs. The enzymatic L-arginine-dependent NO synthase (NOS) pathway is classically viewed as the main source of endogenous NO formation. However, the function of the NOS system is often compromised in various pathologies including kidney, cardiovascular and metabolic diseases. An alternative pathway, the nitrate-nitrite-NO pathway, enables endogenous or dietary-derived inorganic nitrate and nitrite to be recycled via serial reduction to form bioactive nitrogen species, including NO, independent of the NOS system. Signalling via these nitrogen species is linked with cGMP-dependent and independent mechanisms. Novel approaches to restoring NO homeostasis during NOS deficiency and oxidative stress have potential therapeutic applications in kidney, cardiovascular and metabolic disorders.
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Gao X, Liu ZZ, Mohammed H, Braun D, Zhuge Z, Liu M, Lai EY, Jansson L, Carlström M, Patzak A, Persson AEG. Extravasal albumin concentration modulates contractile responses of renal afferent arterioles. Acta Physiol (Oxf) 2018; 222. [PMID: 28748582 DOI: 10.1111/apha.12925] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 01/17/2017] [Accepted: 07/20/2017] [Indexed: 11/30/2022]
Abstract
AIM Afferent arterioles (AA) hold a key position in the regulation of renal blood flow and glomerular filtration rate. Being the effector site of tubuloglomerular feedback, the afferent arteriole contributes to the renal handling of sodium and fluid. Dehydration goes along with increased renal interstitial protein concentration. Here, the hypothesis was tested that extravasal protein concentration directly modulates afferent arteriolar tone, a mechanism which may contribute to body fluid volume control. METHOD The effect of increased extravasal albumin concentration on the vascular reactivity was investigated in renal AA and interlobar arteries of mice, in rat renal AA and in pancreatic islet arterioles. RESULTS Albumin (2 and 4% in the bath solution) significantly potentiated the contractile response of renal afferent arterioles induced by angiotensin II and adenosine, as well as their combination, compared to the control situation (0.1% albumin). Albumin did not influence the contractility of larger renal vessels or pancreatic islet arterioles. Mimicking the increase in the osmolality induced by 4% albumin by applying mannitol to the bath solution also increased the response of renal arterioles to Ang II. However, the effect was smaller compared to that of albumin. The nitric oxide bioavailability, measured by DAF-FM fluorescence, was reduced in afferent arterioles exposed to 4% albumin. CONCLUSION The protein-induced modulation of AA tone is mediated by the increased osmolality as well as by NO scavenging. The results suggest a possible contribution of these mechanisms to the control of extracellular fluid volume via adjustment of renal blood flow and glomerular filtration rate.
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Affiliation(s)
- X. Gao
- Department of Medical Cell Biology; University of Uppsala; Uppsala Sweden
| | - Z. Z. Liu
- Institute of Vegetative Physiology; Charite-Universitätsmedizin Berlin; Berlin Germany
| | - H. Mohammed
- Institute of Vegetative Physiology; Charite-Universitätsmedizin Berlin; Berlin Germany
| | - D. Braun
- Institute of Vegetative Physiology; Charite-Universitätsmedizin Berlin; Berlin Germany
| | - Z. Zhuge
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - M. Liu
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - E. Y. Lai
- Department of Physiology; Zhejiang University; Hangzhou China
| | - L. Jansson
- Department of Medical Cell Biology; University of Uppsala; Uppsala Sweden
| | - M. Carlström
- Department of Physiology and Pharmacology; Karolinska Institutet; Stockholm Sweden
| | - A. Patzak
- Institute of Vegetative Physiology; Charite-Universitätsmedizin Berlin; Berlin Germany
| | - A. E. G. Persson
- Department of Medical Cell Biology; University of Uppsala; Uppsala Sweden
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Abstract
Intrarenal autoregulatory mechanisms maintain renal blood flow (RBF) and glomerular filtration rate (GFR) independent of renal perfusion pressure (RPP) over a defined range (80-180 mmHg). Such autoregulation is mediated largely by the myogenic and the macula densa-tubuloglomerular feedback (MD-TGF) responses that regulate preglomerular vasomotor tone primarily of the afferent arteriole. Differences in response times allow separation of these mechanisms in the time and frequency domains. Mechanotransduction initiating the myogenic response requires a sensing mechanism activated by stretch of vascular smooth muscle cells (VSMCs) and coupled to intracellular signaling pathways eliciting plasma membrane depolarization and a rise in cytosolic free calcium concentration ([Ca(2+)]i). Proposed mechanosensors include epithelial sodium channels (ENaC), integrins, and/or transient receptor potential (TRP) channels. Increased [Ca(2+)]i occurs predominantly by Ca(2+) influx through L-type voltage-operated Ca(2+) channels (VOCC). Increased [Ca(2+)]i activates inositol trisphosphate receptors (IP3R) and ryanodine receptors (RyR) to mobilize Ca(2+) from sarcoplasmic reticular stores. Myogenic vasoconstriction is sustained by increased Ca(2+) sensitivity, mediated by protein kinase C and Rho/Rho-kinase that favors a positive balance between myosin light-chain kinase and phosphatase. Increased RPP activates MD-TGF by transducing a signal of epithelial MD salt reabsorption to adjust afferent arteriolar vasoconstriction. A combination of vascular and tubular mechanisms, novel to the kidney, provides for high autoregulatory efficiency that maintains RBF and GFR, stabilizes sodium excretion, and buffers transmission of RPP to sensitive glomerular capillaries, thereby protecting against hypertensive barotrauma. A unique aspect of the myogenic response in the renal vasculature is modulation of its strength and speed by the MD-TGF and by a connecting tubule glomerular feedback (CT-GF) mechanism. Reactive oxygen species and nitric oxide are modulators of myogenic and MD-TGF mechanisms. Attenuated renal autoregulation contributes to renal damage in many, but not all, models of renal, diabetic, and hypertensive diseases. This review provides a summary of our current knowledge regarding underlying mechanisms enabling renal autoregulation in health and disease and methods used for its study.
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Affiliation(s)
- Mattias Carlström
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Christopher S Wilcox
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - William J Arendshorst
- Department of Medicine, Division of Nephrology and Hypertension and Hypertension, Kidney and Vascular Research Center, Georgetown University, Washington, District of Columbia; Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden; and Department of Cell Biology and Physiology, UNC Kidney Center, and McAllister Heart Institute, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
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Goud PT, Goud AP, Najafi T, Gonik B, Diamond MP, Saed GM, Zhang X, Abu-Soud HM. Direct real-time measurement of intra-oocyte nitric oxide concentration in vivo. PLoS One 2014; 9:e98720. [PMID: 24887331 PMCID: PMC4041775 DOI: 10.1371/journal.pone.0098720] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 05/06/2014] [Indexed: 11/18/2022] Open
Abstract
Nitric oxide (NO) is reported to play significant a role in oocyte activation and maturation, implantation, and early embryonic development. Previously we have shown that NO forms an important component of the oocyte microenvironment, and functions effectively to delay oocyte aging. Thus, precise information about intra-oocyte NO concentrations [NO] will result in designing more accurate treatment plans in assisted reproduction. In this work, the direct, real-time and quantitative intra-oocyte [NO] was measured utilizing an L-shaped amperometric integrated NO-selective electrode. This method not only provides an elegant and convenient approach to real-time the measurement of NO in physiological environments, but also mimics the loss of NO caused by rapid NO diffusion combined with its reactivity in the biological milieu. This experiment suggests that the NO levels of oocytes obtained from young animals are significantly higher than those of oocytes obtained from old animals. Additionally the NO levels stay constant during the measurements; however, the intra-oocyte [NO] is reduced significantly (70-75% reduction) in response to L-NAME incubation, suggesting that NO measurements are truly NOS based rather than caused by an unknown interfering substance in our system. We believe this first demonstration of the direct quantitative measurement of [NO] in situ in an intact cellular complex should be useful in tracking real-time and rapid changes at nanomolar levels. Moreover, this finding confirms and extends our previous work showing that supplementation with NO delays the oocyte aging process.
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Affiliation(s)
- Pravin T. Goud
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics and Gynecology, University of California Davis, Sacramento, California, United States of America
- California IVF Fertility Center, Davis and Sacramento, California, United States of America
| | - Anuradha P. Goud
- California National Primate Research Center, University California Davis, Davis, California, United States of America
| | - Tohid Najafi
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Bernard Gonik
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Michael P. Diamond
- Department of Obstetrics & Gynecology, Georgia Regents University, Augusta, Georgia, United States of America
| | - Ghassan M. Saed
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
| | - Xueji Zhang
- World Precision Instruments, Sarasota, Florida, United States of America
- Research Center for Bioengineering & Sensing Technology, University of Science & Technology, Beijing, P.R. China
| | - Husam M. Abu-Soud
- Division of Reproductive Endocrinology and Infertility, Department of Obstetrics & Gynecology, The C. S. Mott Center for Human Growth and Development, Wayne State University, Detroit, Michigan, United States of America
- Department of Biochemistry and Molecular Biology, Wayne State University, School of Medicine, Detroit, Michigan, United States of America
- * E-mail:
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Namgung B, Liang LH, Kim S. Physiological Significance of Cell-Free Layer and Experimental Determination of its Width in Microcirculatory Vessels. VISUALIZATION AND SIMULATION OF COMPLEX FLOWS IN BIOMEDICAL ENGINEERING 2014. [DOI: 10.1007/978-94-007-7769-9_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Karaaslan F, Denizhan Y, Hester R. A mathematical model of long-term renal sympathetic nerve activity inhibition during an increase in sodium intake. Am J Physiol Regul Integr Comp Physiol 2013; 306:R234-47. [PMID: 24285363 DOI: 10.1152/ajpregu.00302.2012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is well known that renal nerves directly affect renal vascular resistance, tubular sodium reabsorption, and renin secretion. Inhibition of renal sympathetic nerve activity (RSNA) decreases renal vascular resistance, tubular sodium reabsorption, and renin secretion, leading to an increase in sodium excretion. Although several studies show that inhibition of RSNA promotes sodium excretion during an acute blood volume expansion, there is limited research relating to the importance of RSNA inhibition that contributes to sodium homeostasis during a long-term increase in sodium intake. Therefore, to dissect the underlying mechanisms of sodium excretion, a mathematical model of a cardiovascular system consisting of two kidneys, each with an independent RSNA, was developed. Simulations were performed to determine the responses of RSNA and sodium excretion to an increased sodium intake. In these simulations, RSNA in the left kidney was fixed at its normal steady-state value, while RSNA in the contralateral kidney was allowed to change normally in response to the increased sodium intake. The results demonstrate that the fixed-RSNA kidney excretes less sodium than the intact-RSNA collateral kidney. Because each kidney is exposed to the same arterial pressure and circulatory hormones, the impaired sodium excretion in the absence of RSNA inhibition supports the hypothesis that RSNA inhibition contributes to natriuresis in response to a long-term increase in sodium intake.
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Affiliation(s)
- Fatih Karaaslan
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi; and
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12
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Abstract
The kidney plays a fundamental role in maintaining body salt and fluid balance and blood pressure homeostasis through the actions of its proximal and distal tubular segments of nephrons. However, proximal tubules are well recognized to exert a more prominent role than distal counterparts. Proximal tubules are responsible for reabsorbing approximately 65% of filtered load and most, if not all, of filtered amino acids, glucose, solutes, and low molecular weight proteins. Proximal tubules also play a key role in regulating acid-base balance by reabsorbing approximately 80% of filtered bicarbonate. The purpose of this review article is to provide a comprehensive overview of new insights and perspectives into current understanding of proximal tubules of nephrons, with an emphasis on the ultrastructure, molecular biology, cellular and integrative physiology, and the underlying signaling transduction mechanisms. The review is divided into three closely related sections. The first section focuses on the classification of nephrons and recent perspectives on the potential role of nephron numbers in human health and diseases. The second section reviews recent research on the structural and biochemical basis of proximal tubular function. The final section provides a comprehensive overview of new insights and perspectives in the physiological regulation of proximal tubular transport by vasoactive hormones. In the latter section, attention is particularly paid to new insights and perspectives learnt from recent cloning of transporters, development of transgenic animals with knockout or knockin of a particular gene of interest, and mapping of signaling pathways using microarrays and/or physiological proteomic approaches.
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Affiliation(s)
- Jia L Zhuo
- Laboratory of Receptor and Signal Transduction, Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi, USA.
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13
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Abstract
Endothelial responses to stressors are nonuniform and follow the rules of stress-induced hormesis. Responses to the same stressor, depending on its intensity, can range from pro-regenerative to pro-lethal. Exposure to sublethal stressors induces a programmed response that results in stress resistance, whereas a lethal level of a stressor accelerates cell demise. Diverse stressors turn on several default programs within the cells; such programs tend to induce anti-oxidative defenses and anti-inflammatory and pro-survival systems, whereas others tend to switch on pro-apoptotic systems. The response of the kidney endothelium to various forms of acute kidney injury follows these general principles. It is characterized by a proinflammatory pattern that includes up-regulation of different adhesion molecules promoting endothelial-leukocyte interactions, generation of reactive oxygen species, with formation of oxidative and nitrosative stress and mitochondrial damage. Simultaneously, a series of adaptive mechanisms, both local and systemic, are ignited. Stressed endothelial cells broadcast distress signals systemically; these signals can be directed toward the restoration of homeostasis or aggravation of the original insult.
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Affiliation(s)
- Sergey V Brodsky
- Department of Pathology, The Ohio State University, Columbus, OH, USA
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Scully CG, Siu KL, Cupples WA, Braam B, Chon KH. Time–Frequency Approaches for the Detection of Interactions and Temporal Properties in Renal Autoregulation. Ann Biomed Eng 2012; 41:172-84. [DOI: 10.1007/s10439-012-0625-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Accepted: 07/11/2012] [Indexed: 11/28/2022]
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15
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Sandoo A, van Zanten JJCSV, Metsios GS, Carroll D, Kitas GD. The endothelium and its role in regulating vascular tone. Open Cardiovasc Med J 2010; 4:302-12. [PMID: 21339899 PMCID: PMC3040999 DOI: 10.2174/1874192401004010302] [Citation(s) in RCA: 481] [Impact Index Per Article: 34.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2010] [Revised: 11/22/2010] [Accepted: 11/23/2010] [Indexed: 12/16/2022] Open
Abstract
The endothelium forms an important part of the vasculature and is involved in promoting an atheroprotective environment via the complementary actions of endothelial cell-derived vasoactive factors. Disruption of vascular homeostasis can lead to the development of endothelial dysfunction which in turn contributes to the early and late stages of atherosclerosis. In recent years an increasing number of non-invasive vascular tests have been developed to assess vascular structure and function in different clinical populations. The present review aims to provide an insight into the anatomy of the vasculature as well as the underlying endothelial cell physiology. In addition, an in-depth overview of the current methods used to assess vascular function and structure is provided as well as their link to certain clinical populations.
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Affiliation(s)
- Aamer Sandoo
- School of Sport and Exercise Sciences, University of Birmingham, Birmingham, West Midlands, United Kingdom
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16
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Effect of cell-free layer variation on arteriolar wall shear stress. Ann Biomed Eng 2010; 39:359-66. [PMID: 20652744 PMCID: PMC3010219 DOI: 10.1007/s10439-010-0130-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2010] [Accepted: 07/12/2010] [Indexed: 12/31/2022]
Abstract
Relationship between a cell-free layer and wall shear stress (WSS) in small arterioles has been of interest in microcirculatory research. However, influence of temporal variation in the cell-free layer width on the WSS in vivo has not been fully elucidated. In this study, we tested the hypothesis that the layer variation would increase the WSS, and this effect would be enhanced by red blood cell aggregation. The cell-free layer width in arterioles (29.5–67.1 μm ID) in rat cremaster muscles were obtained with a high-speed video camera, and the layer width data were introduced into WSS estimation. Dextran 500 was administrated to elevate the aggregation level of red blood cells to those seen in normal human blood. The variation of the layer was quantified by the variability (coefficient of variation), and its effect on WSS was studied under normal and reduced flow conditions. We found that the dextran-induced red blood cell aggregation significantly elevated the variability (p < 0.01) at low pseudoshear rates of 9.2 ± 0.6 s−1. The WSS estimated without taking account of the variability showed underestimation of its value than that of with consideration of the variability under all flow conditions, and this effect became more pronounced with increasing the variability. The variation of the cell-free layer should, therefore, be considered in the determination of the WSS particularly in the presence of red blood cell aggregation under reduced flow condition.
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Helle F, Iversen BM, Chatziantoniou C. Losartan increases NO release in afferent arterioles during regression of l-NAME-induced renal damage. Am J Physiol Renal Physiol 2010; 298:F1170-7. [DOI: 10.1152/ajprenal.00056.2009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Inhibition of nitric oxide synthesis (NOS) induces hypertension and heavy proteinuria. Renal structure and function have shown striking improvement after interventions targeting ANG II or endothelin (ET) receptors in rats recovering after long-term NOS inhibition. To search for mechanisms underlying losartan-assisted regression of renal disease in rodents, we measured NO release and contractility to ET in afferent arterioles (AAs) from Sprague-Dawley rats recovering for 2 wk after 4 wk of NG-nitro-l-arginine methyl ester treatment. Losartan administration during the recovery period decreased blood pressure (113 ± 4 vs. 146 ± 5 mmHg, P < 0.01), reduced protein/creatinine ratio more (proteinuria decrease: Δ1,836 ± 214 vs. Δ1,024 ± 180 mg/mmol, P < 0.01), and normalized microvascular hypertrophy (AA media/lumen ratio: 1.74 ± 0.05 vs. 2.09 ± 0.08, P < 0.05) compared with no treatment. In diaminofluorescein-FM-loaded AAs from losartan-treated animals, NO release (% of baseline) was increased compared with untreated animals after stimulation with 10−7 M ACh (118 ± 4 vs. 90 ± 7%, t = 560 s, P < 0.001) and 10−9 M ET (123 ± 4 vs. 101 ± 5%, t = 560 s, P < 0.001). There was also a blunted contractile response to 10−7 M ET in AAs from losartan-treated animals compared with untreated animals (Δ4.01 ± 2.9 vs. Δ14.6 ± 1.7 μm, P < 0.01), which disappeared after acute NOS inhibition (Δ10.7 ± 3.7 vs. Δ12.5 ± 2.9 μm, not significant). Contractile dose responses to ET (10−9, 10−8, 10−7 M) were enhanced by NOS inhibition and blunted by exogenous NO (10−2 mM S-nitroso- N-acetyl-penicillamine) in losartan-treated but not in untreated vessels. Reducing blood pressure similar to losartan with hydralazine did not improve AA hypertrophy, ET-induced contractility, ET-induced NO release, and NO sensitivity. In conclusion, blockade of the local action of ANG II improved endothelial function in AAs, a mechanism that is likely to contribute to the beneficial effects of AT1aR antagonism during the recovery of renal function after long-term NOS inhibition in rats.
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Affiliation(s)
- Frank Helle
- Institut National de la Santé et de la Recherche Médicale U702, Hôpital Tenon, Paris
- Renal Research Group, Institute of Medicine, University of Bergen, Bergen; and
- Haukeland University Hospital, Bergen, Norway
| | - Bjarne M. Iversen
- Renal Research Group, Institute of Medicine, University of Bergen, Bergen; and
- Haukeland University Hospital, Bergen, Norway
| | - Christos Chatziantoniou
- Institut National de la Santé et de la Recherche Médicale U702, Hôpital Tenon, Paris
- Pierre et Marie Curie University, Paris, France
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18
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Sullivan JC, Pardieck JL, Brinson K, Kang KT. Effects of estradiol on renal cyclic guanosine monophosphate and oxidative stress in spontaneously hypertensive rats. ACTA ACUST UNITED AC 2010; 6:498-510. [PMID: 19850246 DOI: 10.1016/j.genm.2009.09.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/10/2009] [Indexed: 01/02/2023]
Abstract
BACKGROUND Evidence suggests that estradiol offers protection against the development of cardiovascular and renal pathologies, although the mechanisms involved are still under investigation. The nitric oxide (NO) pathway regulates blood pressure and kidney function, and estradiol is associated with increases in NO bioavailability. We hypothesized that in female spontaneously hypertensive rats (SHRs), estra-diol increases NO bioavailability, activates the NO synthase (NOS) pathway, and suppresses superoxide production compared with rats that underwent ovariectomy (OVX). OBJECTIVE The goal of this study was to determine whether estradiol regulates the NO/cyclic guanosine monophosphate (cGMP) pathway and superoxide levels in the kidneys of female SHR. METHODS Three types of SHRs were studied: gonad-intact females, OVX rats, and OVX rats with estra-diol replacement (OVX+E). Renal cortical cGMP levels were measured to assess NO bioavailability. NOS enzymatic activity, NOS protein expression, basal superoxide production, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity were measured in the renal cortex. RESULTS Fifty-six SHRs were included in the study (17 intact females, 21 OVX rats, 18 OVX+E rats). Mean (SEM) cGMP levels were significantly lower in the renal cortex of OVX rats (0.03 [0.008] pmol/mg, n = 5) than in intact females (0.1 [0.02] pmol/mg, n = 6; P < 0.05), and estradiol restored cGMP levels to those seen in intact females (0.1 [0.01] pmol/mg, n = 5; P < 0.05). Despite a decrease in cGMP following OVX, renal cortical NOS activity, NOS1 and NOS3 protein expression, and the phosphorylation status of NOS3 were comparable among the 3 groups (n = 7-9 per group). However, mean basal superoxide production in the renal cortex was higher in OVX rats (3.2 [0.3] cpm/mg, n = 12) than in intact females (1.9 [0.3] cpm/mg, n = 8; P < 0.05) and lower in OVX+E rats (1.3 [0.3] cpm/mg, n = 9; P < 0.05). Mean NADPH oxidase activity was comparable in the renal cortex of intact females and OVX rats (81 [4] and 83 [12] cpm/35 microg, respectively [n = 5 per group]). OVX+E rats had significantly lower mean renal cortical NADPH oxidase activity than did rats in the other groups (45 [6] cpm/35 microg, n = 6; P < 0.05), and the decrease in activity was accompanied by a decrease in p22(phox) protein expression. CONCLUSIONS In vivo manipulations of estradiol levels influenced renal cortical NO bioavailability, as assessed indirectly by cGMP measurements. The decrease in cGMP following OVX was not due to alterations in the activity or expression of NOS.
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Wagner C, de Wit C, Kurtz L, Grünberger C, Kurtz A, Schweda F. Connexin40 is essential for the pressure control of renin synthesis and secretion. Circ Res 2007; 100:556-63. [PMID: 17255527 DOI: 10.1161/01.res.0000258856.19922.45] [Citation(s) in RCA: 166] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Renin secretion and synthesis in renal juxtaglomerular cells are controlled by short feed back loops involving angiotensin II and the intrarenal blood pressure. The operating mechanisms of these negative feed back regulators are widely unknown, except for the fact that both require calcium to exert their inhibitory action. We here show that in the absence of connexin40 (Cx40), which form gap junctions between juxtaglomerular and endothelial cells, the negative control of renin secretion and synthesis by angiotensin II and by intravasal pressure is abrogated, while the regulation by salt intake and beta-adrenergic stimulation is maintained. Renin secretion from Cx40-deficient kidneys or wild-type kidneys treated with the nonselective gap junction blocker 18alpha-glycyrrhetinic acid (10 micromol/L) resembles the situation in wild-type kidneys in the absence of extracellular calcium. This disturbed regulation is reflected by an enhanced plasma renin concentration despite an elevated blood pressure in Cx40-deficient mice. These findings indicate that Cx40 connexins and likely intercellular communication via Cx40-dependent gap junctions mediate the calcium-dependent inhibitor effects of angiotensin II and of intrarenal pressure on renin secretion and synthesis. Because Cx40 gap junctions are also formed between renin producing cells and endothelial cells our finding could provide additional information to suggest that the endothelium may be strongly involved in the control of the renin system.
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Affiliation(s)
- Charlotte Wagner
- Physiologisches Institut der Universität Regensburg, Regensburg, Germany.
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20
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Abstract
PURPOSE OF REVIEW The balance of angiotensin II and nitric oxide determines the sensitivity of the tubuloglomerular feedback mechanism, renal vascular resistance and filtration rate. Angiotensin II induces nitric oxide release, but the role of angiotensin II receptors here is not fully understood. Further, the angiotensin II-nitric oxide interaction can be modulated by reactive oxygen species. This review focuses on the angiotensin II-nitric oxide interaction and their modulation by reactive oxygen species in the control of renal blood flow. RECENT FINDINGS Ideas about the role of angiotensin II type 1 and angiotensin II type 2 receptors are extended by the observation of angiotensin II type 1-mediated nitric oxide release with direct effects on vascular tone, tubuloglomerular feedback and sympathetic neurotransmission. Angiotensin receptors elicit disparate effects on intrarenal circulation. Angiotensin II-nitric oxide interactions are modulated by reactive oxygen species, as shown by angiotensin II type 1-mediated activation of superoxide and depression of antioxidant enzymes leading to reduced nitric oxide concentration - mechanisms that may be also important in angiotensin II-dependent hypertension. SUMMARY Recent studies show that angiotensin II stimulates the nitric oxide system via angiotensin II type 1 and angiotensin II type 2 receptors, whereas receptors exert different effects on renal and medullary flow. The interaction via angiotensin II type 1 is modulated by reactive oxygen species.
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Affiliation(s)
- Andreas Patzak
- Johannes-Müller-Institute of Physiology, Humboldt-University of Berlin, University Hospital Charité, Berlin, Germany
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21
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Current World Literature. Curr Opin Nephrol Hypertens 2007; 16:52-7. [PMID: 17143072 DOI: 10.1097/mnh.0b013e32801271d6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Acute renal failure presents a serious and life-threatening problem in hospitalized patients. Current therapies address the systemic alterations in renal failure. Cellular changes also occur. These changes affect the glomerular filtration rate and the integrity of the glomerular membrane. ET-1, the most potent vasoconstrictor known, has a negative effect on both the rate of filtration and the integrity of the filtering membrane in renal failure. Using ET-1 antagonists along with the current therapies may prove useful in patients.
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Affiliation(s)
- Allan D Angerio
- School of Nursing and Health Studies, Georgetown University, Washington, DC, USA.
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23
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Abstract
PURPOSE OF REVIEW Nitric oxide is a potent, endogenous vasodilator that regulates systemic blood pressure and renal function, among other functions. The bioactivity of nitric oxide is reduced by superoxide, a major reactive oxygen species. Overproduction of superoxide and other related reactive oxygen species resulting in oxidative stress reduces the biological effects of nitric oxide. Though both of these highly reactive species have distinct roles in other pathways, their interaction is emerging as a major regulatory factor in normal and pathological renal function. The purpose of this review is to highlight the recent studies on oxidative stress and nitric oxide in the kidney, focusing on their interaction in normal and pathological conditions. RECENT FINDINGS Studies have focused on pro-oxidant pathways and nitric oxide defense systems in normal and pathological conditions. The oxidant potential of uncoupled nitric oxide synthases is gaining interest as a pro-oxidant system. Both animal and clinical studies have attempted to identify strategies to intervene at various stages of the oxidant-nitric oxide pathways to improve function during renal failure. SUMMARY Several new approaches and provocative findings have emerged over the last year. A regulatory role for nitric oxide in the control of the renal microcirculation and as a participant in tubule function is further described. New information of the cause and possible prevention of acute and chronic renal failure has also been produced in the last year. These advances demonstrate the value of research in the normal and pathological roles of oxidative stress and nitric oxide in the kidney.
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Affiliation(s)
- Magali Araujo
- Division of Nephrology and Hypertension, Georgetown University, 4000 Reservoir Road, Washington, DC 20057, USA
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