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Yoshida Y, Fukuda T, Fukuoka K, Nagayama T, Tanihara T, Nishikawa N, Otsuki K, Terada Y, Hamamura K, Oyama K, Tsuruta A, Mayanagi K, Koyanagi S, Matsunaga N, Ohdo S. Time-Dependent Differences in Vancomycin Sensitivity of Macrophages Underlie Vancomycin-Induced Acute Kidney Injury. J Pharmacol Exp Ther 2024; 388:218-227. [PMID: 38050132 DOI: 10.1124/jpet.123.001864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 10/21/2023] [Accepted: 11/07/2023] [Indexed: 12/06/2023] Open
Abstract
Although vancomycin (VCM)-frequently used to treat drug-resistant bacterial infections-often induces acute kidney injury (AKI), discontinuation of the drug is the only effective treatment; therefore, analysis of effective avoidance methods is urgently needed. Here, we report the differences in the induction of AKI by VCM in 1/2-nephrectomized mice depending on the time of administration. Despite the lack of difference in the accumulation of VCM in the kidney between the light (ZT2) and dark (ZT14) phases, the expression of AKI markers due to VCM was observed only in the ZT2 treatment. Genomic analysis of the kidney suggested that the time of administration was involved in VCM-induced changes in monocyte and macrophage activity, and VCM had time-dependent effects on renal macrophage abundance, ATP activity, and interleukin (IL)-1β expression. Furthermore, the depletion of macrophages with clodronate abolished the induction of IL-1β and AKI marker expression by VCM administration at ZT2. This study provides evidence of the need for time-dependent pharmacodynamic considerations in the prevention of VCM-induced AKI as well as the potential for macrophage-targeted AKI therapy. SIGNIFICANCE STATEMENT: There is a time of administration at which vancomycin (VCM)-induced renal injury is more and less likely to occur, and macrophages are involved in this difference. Therefore, there is a need for time-dependent pharmacodynamic considerations in the prevention of VCM-induced acute kidney injury as well as the potential for macrophage-targeted acute kidney injury therapy.
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Affiliation(s)
- Yuya Yoshida
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Taiki Fukuda
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kohei Fukuoka
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Toshitaka Nagayama
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Tomohito Tanihara
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Naoki Nishikawa
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kaita Otsuki
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Yuma Terada
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kengo Hamamura
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kosuke Oyama
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Akito Tsuruta
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Kota Mayanagi
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Satoru Koyanagi
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Naoya Matsunaga
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
| | - Shigehiro Ohdo
- Departments of Clinical Pharmacokinetics (Y.Y., T.F., T.N., T.T., N.N., K.O., Y.T., K.H., N.M.), Pharmaceutics (K.F., K.O., S.O.), Glocal Healthcare Science (A.T., S.K.), and Drug Discovery Structural Biology (K.M.), Faculty of Pharmaceutical Sciences, Kyushu University, Fukuoka, Japan
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Curcumin, an Inhibitor of p300-HAT Activity, Suppresses the Development of Hypertension-Induced Left Ventricular Hypertrophy with Preserved Ejection Fraction in Dahl Rats. Nutrients 2021; 13:nu13082608. [PMID: 34444769 PMCID: PMC8397934 DOI: 10.3390/nu13082608] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/25/2021] [Accepted: 07/25/2021] [Indexed: 12/21/2022] Open
Abstract
We found that curcumin, a p300 histone acetyltransferase (HAT) inhibitor, prevents cardiac hypertrophy and systolic dysfunction at the stage of chronic heart failure in Dahl salt-sensitive rats (DS). It is unclear whether curcumin suppresses the development of hypertension-induced left ventricular hypertrophy (LVH) with a preserved ejection fraction. Therefore, in this study, we randomized DS (n = 16) and Dahl salt-resistant (DR) rats (n = 10) at 6 weeks of age to either curcumin or vehicle groups. These rats were fed a high-salt diet and orally administrated with 50 mg/kg/d curcumin or its vehicle for 6 weeks. Both curcumin and vehicle treatment groups exhibited similar degrees of high-salt diet-induced hypertension in DS rats. Curcumin significantly decreased hypertension-induced increase in posterior wall thickness and LV mass index, without affecting the systolic function. It also significantly reduced hypertension-induced increases in myocardial cell diameter, perivascular fibrosis and transcriptions of the hypertrophy-response gene. Moreover, it significantly attenuated the acetylation levels of GATA4 in the hearts of DS rats. A p300 HAT inhibitor, curcumin, suppresses the development of hypertension-induced LVH, without affecting blood pressure and systolic function. Therefore, curcumin may be used for the prevention of development of LVH in patients with hypertension.
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Romero CA, Carretero OA. Tubule-vascular feedback in renal autoregulation. Am J Physiol Renal Physiol 2019; 316:F1218-F1226. [PMID: 30838873 DOI: 10.1152/ajprenal.00381.2018] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Afferent arteriole (Af-Art) diameter regulates pressure and flow into the glomerulus, which are the main determinants of the glomerular filtration rate. Thus, Af-Art resistance is crucial for Na+ filtration. Af-Arts play a role as integrative centers, where systemic and local systems interact to determine the final degree of resistance. The tubule of a single nephron contacts an Af-Art of the same nephron at two locations: in the transition of the thick ascending limb to the distal tubule (macula densa) and again in the connecting tubule. These two sites are the anatomic basis of two intrinsic feedback mechanisms: tubule-glomerular feedback and connecting tubule-glomerular feedback. The cross communications between the tubules and Af-Arts integrate tubular Na+ and water processing with the hemodynamic conditions of the kidneys. Tubule-glomerular feedback provides negative feedback that tends to avoid salt loss, and connecting tubule-glomerular feedback provides positive feedback that favors salt excretion by modulating tubule-glomerular feedback (resetting it) and increasing glomerular filtration rate. These feedback mechanisms are also exposed to systemic modulators (hormones and the nervous system); however, they can work in isolated kidneys or nephrons. The exaggerated activation or absence of any of these mechanisms may lead to disequilibrium in salt and water homeostasis, especially in extreme conditions (e.g., high-salt diet/low-salt diet) and may be part of the pathogenesis of some diseases. In this review, we focus on molecular signaling, feedback interactions, and the physiological roles of these two feedback mechanisms.
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Affiliation(s)
- Cesar A Romero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
| | - Oscar A Carretero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital , Detroit, Michigan
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Boudaka A, Al-Suleimani M, Al-Lawati I, Baomar H, Al-Siyabi S, Zadjali F. Downregulation of endothelial transient receptor potential vanilloid type 4 channel underlines impaired endothelial nitric oxide-mediated relaxation in the mesenteric arteries of hypertensive rats. Physiol Res 2019; 68:219-231. [PMID: 30628831 DOI: 10.33549/physiolres.933952] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The endothelium contributes to the maintenance of vasodilator tone by releasing endothelium-derived relaxing factors, including nitric oxide (NO). In hypertension, endothelial nitric oxide synthase (eNOS) produces less NO and could be one of the contributing factors to the increased peripheral vascular resistance. Agonist-induced Ca(2+) entry is essential for the activation of eNOS. The transient receptor potential vanilloid type 4 (TRPV4) channel, a Ca(2+)-permeant cation channel, is expressed in the endothelial cells and involved in the regulation of vascular tone. The present study aimed to investigate the role of TRPV4 channel in endothelium-dependent NO-mediated relaxation of the resistance artery in hypertensive rats. Using a wire myograph, relaxation response to the TRPV4 activator, 4alpha-phorbol-12,13-didecanoate (4alphaPDD) was assessed in mesenteric arteries obtained from Wistar-Kyoto (WKY) and spontaneously hypertensive rats (SHRs). Compared to WKY, SHR demonstrated a significantly attenuated 4alphaPDD-induced endothelium-dependent NO-mediated relaxation. Immunohistochemical analysis revealed positive staining for TRPV4 in the endothelium of mesenteric artery sections in both WKY and SHR. Furthermore, TRPV4 mRNA and protein expressions in SHR were significantly lower than their expression levels in WKY rats. We conclude that 4alphaPDD-induced endothelium-dependent NO-mediated vasorelaxation is reduced in SHR and downregulation of TRPV4 could be one of the contributing mechanisms.
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Affiliation(s)
- A Boudaka
- Department of Physiology, College of Medicine and Health Sciences, Sultan Qaboos University, Al-Khoud, Sultanate of Oman.
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Wang H, Romero CA, Masjoan Juncos JX, Monu SR, Peterson EL, Carretero OA. Effect of salt intake on afferent arteriolar dilatation: role of connecting tubule glomerular feedback (CTGF). Am J Physiol Renal Physiol 2017; 313:F1209-F1215. [PMID: 28835421 DOI: 10.1152/ajprenal.00320.2017] [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: 06/22/2017] [Revised: 08/10/2017] [Accepted: 08/16/2017] [Indexed: 01/13/2023] Open
Abstract
Afferent arteriole (Af-Art) resistance is modulated by two intrinsic nephron feedbacks: 1) the vasoconstrictor tubuloglomerular feedback (TGF) mediated by Na+-K+-2Cl- cotransporters (NKCC2) in the macula densa and blocked by furosemide and 2) the vasodilator connecting tubule glomerular feedback (CTGF), mediated by epithelial Na+ channels (ENaC) in the connecting tubule and blocked by benzamil. High salt intake reduces Af-Art vasoconstrictor ability in Dahl salt-sensitive rats (Dahl SS). Previously, we measured CTGF indirectly, by differences between TGF responses with and without CTGF inhibition. We recently developed a new method to measure CTGF more directly by simultaneously inhibiting NKCC2 and the Na+/H+ exchanger (NHE). We hypothesize that in vivo during simultaneous inhibition of NKCC2 and NHE, CTGF causes an Af-Art dilatation revealed by an increase in stop-flow pressure (PSF) in Dahl SS and that is enhanced with a high salt intake. In the presence of furosemide alone, increasing nephron perfusion did not change the PSF in either Dahl salt-resistant rats (Dahl SR) or Dahl SS. When furosemide and an NHE inhibitor, dimethylamiloride, were perfused simultaneously, an increase in tubular flow caused Af-Art dilatation that was demonstrated by an increase in PSF. This increase was greater in Dahl SS [4.5 ± 0.4 (SE) mmHg] than in Dahl SR (2.5 ± 0.3 mmHg; P < 0.01). We confirmed that CTGF causes this vasodilation, since benzamil completely blocked this effect. However, a high salt intake did not augment the Af-Art dilatation. We conclude that during simultaneous inhibition of NKCC2 and NHE in the nephron, CTGF induces Af-Art dilatation and a high salt intake failed to enhance this effect.
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Affiliation(s)
- Hong Wang
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Cesar A Romero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - J X Masjoan Juncos
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Sumit R Monu
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
| | - Edward L Peterson
- Department of Public Health Sciences, Henry Ford Hospital, Detroit, Michigan
| | - Oscar A Carretero
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan; and
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Zhai Z, Wang Z, Wang L, Chen S, Ren H, Wang D. Relationship between inducible NOS single-nucleotide polymorphisms and hypertension in Han Chinese. Herz 2017; 43:461-465. [PMID: 28685250 DOI: 10.1007/s00059-017-4591-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 05/31/2017] [Accepted: 06/05/2017] [Indexed: 11/24/2022]
Abstract
BACKGROUND Inducible nitric oxide synthase (iNOS) single-nucleotide polymorphisms have been reported to confer susceptibility to hypertension, but no consensus has been reached. The aim of this study was to investigate the association between iNOS and hypertension in a Chinese population. METHODS This was a case-control study including 1172 hypertensive and 1172 control subjects to investigate the association between iNOS and hypertension. RESULTS There were significant differences in the distribution of genotype and allele frequencies of rs2779249 and rs2297518 between hypertensive and normotensive subjects. Logistic regression analyses were performed with different genetic models (additive, dominant, recessive) adjusting for confounding risk covariates, including age, sex, body mass index, total cholesterol, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, smoking, drinking, and family history of hypertension. The odds ratio (OR) was 1.27 (1.12, 1.44) in the additive model, 1.31 (1.09, 1.59) in the dominant, and 1.68 (1.28, 2.19) in the recessive model of rs2779249; the OR was 1.26 (1.06, 1.50) in the additive model and 1.46 (1.13, 1.89) in the dominant model of rs2297518. CONCLUSION The current study provides evidence that iNOS is strongly associated with hypertension.
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Affiliation(s)
- Z Zhai
- Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China.,Department of Cardiology, First Affiliated Hospital, Shihezi Medical College, Shihezi University, 832000, Shihezi, Xinjiang, China
| | - Z Wang
- Department of Cardiology, First Affiliated Hospital, Shihezi Medical College, Shihezi University, 832000, Shihezi, Xinjiang, China.
| | - L Wang
- Department of Cardiology, First Affiliated Hospital, Shihezi Medical College, Shihezi University, 832000, Shihezi, Xinjiang, China
| | - S Chen
- Department of Cardiology, First Affiliated Hospital, Shihezi Medical College, Shihezi University, 832000, Shihezi, Xinjiang, China
| | - H Ren
- Department of Cardiology, First Affiliated Hospital, Shihezi Medical College, Shihezi University, 832000, Shihezi, Xinjiang, China
| | - D Wang
- Department of Cardiology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 430030, Wuhan, Hubei, China
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Lin YC, Hwu Y, Huang GS, Hsiao M, Lee TT, Yang SM, Lee TK, Chen NY, Yang SS, Chen A, Ka SM. Differential synchrotron X-ray imaging markers based on the renal microvasculature for tubulointerstitial lesions and glomerulopathy. Sci Rep 2017; 7:3488. [PMID: 28615647 PMCID: PMC5471266 DOI: 10.1038/s41598-017-03677-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Accepted: 05/03/2017] [Indexed: 12/13/2022] Open
Abstract
High resolution synchrotron microtomography capable of revealing microvessels in three dimensional (3D) establishes distinct imaging markers of mouse kidney disease strongly associated to renal tubulointerstitial (TI) lesions and glomerulopathy. Two complementary mouse models of chronic kidney disease (CKD), unilateral ureteral obstruction (UUO) and focal segmental glomerulosclerosis (FSGS), were used and five candidates of unique 3D imaging markers were identified. Our characterization to differentially reflect the altered microvasculature of renal TI lesions and/or glomerulopathy demonstrated these image features can be used to differentiate the disease status and the possible cause therefore qualified as image markers. These 3D imaging markers were further correlated with the histopathology and renal microvessel-based molecular study using antibodies against vascular endothelial cells (CD31), the connective tissue growth factor or the vascular endothelial growth factor. We also found that these 3D imaging markers individually characterize the development of renal TI lesions or glomerulopathy, quantitative and integrated use of all of them provide more information for differentiating the two renal conditions. Our findings thus establish a practical strategy to characterize the CKD-associated renal injuries by the microangiography-based 3D imaging and highlight the impact of dysfunctional microvasculature as a whole on the pathogenesis of the renal lesions.
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Affiliation(s)
- Yu-Chuan Lin
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan
| | - Yeukuang Hwu
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Guo-Shu Huang
- Department of Radiology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Michael Hsiao
- Genomics Research Center, Academia Sinica, Taipei, Taiwan
| | - Tsung-Tse Lee
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Shun-Min Yang
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Ting-Kuo Lee
- Institute of Physics, Academia Sinica, Taipei, Taiwan
| | - Nan-Yow Chen
- National Center for High-Performance Computing, Hsinchu, Taiwan
| | - Sung-Sen Yang
- Division of Nephrology, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan
| | - Ann Chen
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
- Department of Pathology, Tri-Service General Hospital, National Defense Medical Center, Taipei, Taiwan.
| | - Shuk-Man Ka
- Graduate Institute of Life Sciences, National Defense Medical Center, Taipei, Taiwan.
- Graduate Institute of Aerospace and Undersea Medicine, Academy of Medicine, National Defense Medical Center, Taipei, Taiwan.
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Pereira CA, Ferreira NS, Mestriner FL, Antunes-Rodrigues J, Evora PR, Resstel LB, Carneiro FS, Tostes RC. Chronic fluoxetine treatment increases NO bioavailability and calcium-sensitive potassium channels activation in rat mesenteric resistance arteries. Eur J Pharmacol 2015; 765:375-83. [DOI: 10.1016/j.ejphar.2015.09.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2015] [Revised: 08/26/2015] [Accepted: 09/01/2015] [Indexed: 10/23/2022]
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Moreira MCDS, Pinto ISDJ, Mourão AA, Fajemiroye JO, Colombari E, Reis ÂADS, Freiria-Oliveira AH, Ferreira-Neto ML, Pedrino GR. Does the sympathetic nervous system contribute to the pathophysiology of metabolic syndrome? Front Physiol 2015; 6:234. [PMID: 26379553 PMCID: PMC4548210 DOI: 10.3389/fphys.2015.00234] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 08/05/2015] [Indexed: 12/18/2022] Open
Abstract
The metabolic syndrome (MS), formally known as syndrome X, is a clustering of several risk factors such as obesity, hypertension, insulin resistance, and dislypidemia which could lead to the development of diabetes and cardiovascular diseases (CVD). The frequent changes in the definition and diagnostic criteria of MS are indications of the controversy and the challenges surrounding the understanding of this syndrome among researchers. Obesity and insulin resistance are leading risk factors of MS. Moreover, obesity and hypertension are closely associated to the increase and aggravation of oxidative stress. The recommended treatment of MS frequently involves change of lifestyles to prevent weight gain. MS is not only an important screening tool for the identification of individuals at high risk of CVD and diabetes but also an indicator of suitable treatment. As sympathetic disturbances and oxidative stress are often associated with obesity and hypertension, the present review summarizes the role of sympathetic nervous system and oxidative stress in the MS.
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Affiliation(s)
- Marina C Dos Santos Moreira
- Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Federal University of Goiás Goiânia, Brazil
| | - Izabella S de Jesus Pinto
- Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Federal University of Goiás Goiânia, Brazil
| | - Aline A Mourão
- Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Federal University of Goiás Goiânia, Brazil
| | - James O Fajemiroye
- Laboratory of Pharmacology of Natural Products, Federal University of Goiás Goiânia, Brazil
| | - Eduardo Colombari
- Department of Physiology and Pathology, School of Dentistry, Universidade Estadual Paulista Araraquara, Brazil
| | - Ângela A da Silva Reis
- Department of Biochemistry and Molecular Biology, Federal University of Goiás Goiânia, Brazil
| | - André H Freiria-Oliveira
- Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Federal University of Goiás Goiânia, Brazil
| | - Marcos L Ferreira-Neto
- Laboratory of Experimental Physiology, Faculty of Physical Education, Federal University of Uberlândia Uberlândia, Brazil
| | - Gustavo R Pedrino
- Department of Physiological Sciences, Center for Neuroscience and Cardiovascular Research, Federal University of Goiás Goiânia, Brazil
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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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Wang H, D'Ambrosio MA, Garvin JL, Ren Y, Carretero OA. Connecting tubule glomerular feedback in hypertension. Hypertension 2013; 62:738-45. [PMID: 23959547 DOI: 10.1161/hypertensionaha.113.01846] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
In Dahl salt-sensitive rats (Dahl SS), glomerular capillary pressure increases in response to high salt intake and this is accompanied by significant glomerular injury compared with spontaneously hypertensive rats with similar blood pressure. Glomerular capillary pressure is controlled mainly by afferent arteriolar resistance, which is regulated by the vasoconstrictor tubule glomerular feedback (TGF) and the vasodilator connecting TGF (CTGF). We hypothesized that Dahl SS have a decreased TGF response and enhanced TGF resetting compared with spontaneously hypertensive rats, and that these differences are attributable in part to an increase in CTGF. In vivo, using micropuncture we measured stop-flow pressure (a surrogate of glomerular capillary pressure). TGF was calculated as the maximal decrease in stop-flow pressure caused by increasing nephron perfusion, TGF resetting as the attenuation in TGF induced by high salt diet, and CTGF as the difference in TGF response before and during CTGF inhibition with benzamil. Compared with spontaneously hypertensive rats, Dahl SS had (1) lower TGF responses in normal (6.6±0.1 versus 11.0±0.2 mm Hg; P<0.001) and high-salt diets (3.3±0.1 versus 10.1±0.3 mm Hg; P<0.001), (2) greater TGF resetting (3.3±0.1 versus 1.0±0.3 mm Hg; P<0.001), and (3) greater CTGF (3.4±0.4 versus 1.2±0.1 mm Hg; P<0.001). We conclude that Dahl SS have lower TGF and greater CTGF than spontaneously hypertensive rats, and that CTGF antagonizes TGF. Furthermore, CTGF is enhanced by a high-salt diet and contributes significantly to TGF resetting. Our findings may explain in part the increase in vasodilatation, glomerular capillary pressure, and glomerular damage in SS hypertension during high salt intake.
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Affiliation(s)
- Hong Wang
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, 2799 West Grand Blvd, Detroit, MI 48202.
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12
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Zicha J, Dobešová Z, Vokurková M, Rauchová H, Hojná S, Kadlecová M, Behuliak M, Vaněčková I, Kuneš J. Age-dependent salt hypertension in Dahl rats: fifty years of research. Physiol Res 2013; 61:S35-S87. [PMID: 22827876 DOI: 10.33549/physiolres.932363] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Fifty years ago, Lewis K. Dahl has presented a new model of salt hypertension - salt-sensitive and salt-resistant Dahl rats. Twenty years later, John P. Rapp has published the first and so far the only comprehensive review on this rat model covering numerous aspects of pathophysiology and genetics of salt hypertension. When we summarized 25 years of our own research on Dahl/Rapp rats, we have realized the need to outline principal abnormalities of this model, to show their interactions at different levels of the organism and to highlight the ontogenetic aspects of salt hypertension development. Our attention was focused on some cellular aspects (cell membrane function, ion transport, cell calcium handling), intra- and extrarenal factors affecting renal function and/or renal injury, local and systemic effects of renin-angiotensin-aldosterone system, endothelial and smooth muscle changes responsible for abnormal vascular contraction or relaxation, altered balance between various vasoconstrictor and vasodilator systems in blood pressure maintenance as well as on the central nervous and peripheral mechanisms involved in the regulation of circulatory homeostasis. We also searched for the age-dependent impact of environmental and pharmacological interventions, which modify the development of high blood pressure and/or organ damage, if they influence the salt-sensitive organism in particular critical periods of development (developmental windows). Thus, severe self-sustaining salt hypertension in young Dahl rats is characterized by pronounced dysbalance between augmented sympathetic hyperactivity and relative nitric oxide deficiency, attenuated baroreflex as well as by a major increase of residual blood pressure indicating profound remodeling of resistance vessels. Salt hypertension development in young but not in adult Dahl rats can be attenuated by preventive increase of potassium or calcium intake. On the contrary, moderate salt hypertension in adult Dahl rats is attenuated by superoxide scavenging or endothelin-A receptor blockade which do not affect salt hypertension development in young animals.
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Affiliation(s)
- J Zicha
- Centre for Cardiovascular Research, Prague, Czech Republic.
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13
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Impaired pressure natriuresis is associated with interstitial inflammation in salt-sensitive hypertension. Curr Opin Nephrol Hypertens 2013; 22:37-44. [PMID: 23165109 DOI: 10.1097/mnh.0b013e32835b3d54] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
PURPOSE OF REVIEW Impairment of the pressure natriuresis relationship is a central event in the pathogenesis of hypertension. Renal tubulointerstitial inflammation results in salt-sensitive hypertension and, until recently, the changes in pressure natriuresis induced by renal inflammation received little attention. RECENT FINDINGS Oxidative stress and increased intrarenal angiotensin II activity, in association with rarefaction and loss of peritubular vascular network, may be involved in the inflammation-induced blunting of the natriuresis resulting from increments in renal perfusion pressure. SUMMARY Here, we review the mechanisms for the impairment in pressure natriuresis resulting from renal tubulointerstitial inflammation in reference to the normal physiologic mechanisms involved in this response.
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Huang CF, Hsu CN, Chien SJ, Lin YJ, Huang LT, Tain YL. Aminoguanidine attenuates hypertension, whereas 7-nitroindazole exacerbates kidney damage in spontaneously hypertensive rats: The role of nitric oxide. Eur J Pharmacol 2013. [DOI: 10.1016/j.ejphar.2012.11.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Yamaleyeva LM, Lindsey SH, Varagic J, Zhang LL, Gallagher PE, Chen AF, Chappell MC. Amelioration of renal injury and oxidative stress by the nNOS inhibitor L-VNIO in the salt-sensitive mRen2.Lewis congenic rat. J Cardiovasc Pharmacol 2012; 59:529-38. [PMID: 22370956 PMCID: PMC3369010 DOI: 10.1097/fjc.0b013e31824dd15b] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Salt sensitivity is a key risk factor for cardiovascular disease and renal injury. Alterations in renal nitric oxide may contribute to salt-dependent increases in blood pressure and tissue damage. Therefore, we assessed the expression of nitric oxide synthase (NOS) isoforms in the kidney and the effects of nNOS inhibition on renal injury, inflammation, and oxidative stress in the female mRen2.Lewis rat (mRen), a model of salt-sensitive hypertension. We find that a high-salt diet (4% sodium) significantly reduced endothelial NOS mRNA (2.6-fold) and protein (1.5-fold) but increased nNOS mRNA (2.4-fold) and protein (1.9-fold) in the renal cortex of these animals. Immunostaining for nNOS also seemed higher in macula densa and cortical tubules of the rats fed a high-salt diet. Circulating nitrate and nitrite levels were reduced, including the tissue levels of the NOS cofactor tetrahydrobiopterin. Cortical markers of oxidative stress (4HNE, 8-OH-deoxyguanosine) and fibrosis were increased; however, mRNA levels of the NAD(P)H oxidase components NOX4, p22phox, and p47phox were reduced. Chronic treatment with the nNOS inhibitor N-(1-Imino-3-butenyl)-L-ornithine did not influence systolic blood pressure after 4 weeks but significantly attenuated albuminuria, renal fibrosis, inflammation, and indices of oxidative stress. We conclude that an increase in nNOS expression in conjunction with reduced levels of cortical tetrahydrobiopterin may stimulate oxidative stress and renal injury in the salt-sensitive female mRen2.Lewis rat.
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Affiliation(s)
- Liliya M Yamaleyeva
- The Hypertension and Vascular Research Center, Wake Forest University School of Medicine, Winston-Salem, NC 27157-1095, USA.
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Meng X, Dai X, Liao TD, D'Ambrosio M, Wang F, Yang JJ, Yang XP. Dose-dependent toxic effects of high-dose estrogen on renal and cardiac injury in surgically postmenopausal mice. Life Sci 2010; 88:178-86. [PMID: 21074543 DOI: 10.1016/j.lfs.2010.11.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 10/08/2010] [Accepted: 11/04/2010] [Indexed: 02/07/2023]
Abstract
AIMS We previously found that in mice with experimental myocardial infarction (MI), 17β-estradiol (E2) increased mortality and worsened cardiac remodeling and these deleterious effects were associated with renal enlargement and hydronephrosis in a dose-dependent manner. In the present study we questioned whether E2-induced renal damage predisposes to rather than results from its adverse effects on the heart. MAIN METHODS Ovariectomized (ovx) mice received either placebo (P) or E2 at 0.02 (E2-L, low dose), 0.42 (E2-M, moderate dose) or 4.2 μg/d (E2-H, high dose) for 8 weeks. KEY FINDINGS E2-L partially restored uterine weight and plasma estrogen levels without affecting heart, lung and liver weight, hemodynamic parameters, or heart and kidney morphology and function. E2-M restored normal uterine weight, but this was accompanied by a significant increase in kidney weight, albuminuria, glomerular matrix formation and markers for oxidative stress. E2-H increased uterine weight 4.5-fold and resulted in higher plasma creatinine levels, severe albuminuria, renal tubular dilatation, tubulointerstitial injury, hydronephrosis, glomerulosclerosis and oxidative stress. E2-H also caused ascites, hepatomegaly and fluid retention in the uterine horns but had no significant effect on blood pressure or heart function. SIGNIFICANCE Our data demonstrated that an excessive dose of E2 that raises uterine weight beyond physiological levels adversely affects the kidney even before it damages the heart. We believe estrogen dosage should be taken into account when considering hormonal replacement therapy, since inappropriate doses of E2 may damage not only the heart but also the kidney.
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Affiliation(s)
- Xiaomei Meng
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
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Varagic J, Ahmad S, Brosnihan KB, Habibi J, Tilmon RD, Sowers JR, Ferrario CM. Salt-induced renal injury in spontaneously hypertensive rats: effects of nebivolol. Am J Nephrol 2010; 32:557-66. [PMID: 21042014 DOI: 10.1159/000321471] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Accepted: 09/25/2010] [Indexed: 12/19/2022]
Abstract
BACKGROUND we investigated renal effects of nebivolol, a selective β(1)-receptor blocker with additional antioxidative ability, in spontaneously hypertensive rats (SHR) where increased salt intake induces oxidative stress and worsens renal function as a result of further activation of the renin-angiotensin and sympathetic nervous systems. METHODS male SHR were given an 8% salt diet (HS; n = 22) for 5 weeks; their age-matched controls (n = 9) received standard chow. Nebivolol was given at a dose of 10 mg/kg/day for 5 weeks in 11 HS rats. RESULTS HS increased blood pressure, plasma renin concentration, urinary protein excretion, and renal nitroxidative stress while decreasing renal blood flow and angiotensin 1-7 receptor (mas) protein expression. There was no change in angiotensin II type 1 receptor expression among the experimental groups. Nebivolol did not alter the salt-induced increase in blood pressure but reduced urinary protein excretion, plasma renin concentration, and nitroxidative stress. Nebivolol also increased neuronal NOS expression while preventing the salt-induced decrease in renal blood flow and mas protein expression. CONCLUSION nebivolol prevented salt-induced kidney injury and associated proteinuria in SHR through a blood pressure-independent mechanism. Its protective effects may be related to reduction in oxidative stress, increases in neuronal NOS and restoration of angiotensin II type 1/mas receptor balance.
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Affiliation(s)
- Jasmina Varagic
- Hypertension and Vascular Research Center, Wake Forest University, Winston-Salem, NC 27157, USA.
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Viswanathan G, Gilbert S. The cardiorenal syndrome: making the connection. Int J Nephrol 2010; 2011:283137. [PMID: 21151533 PMCID: PMC2989717 DOI: 10.4061/2011/283137] [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: 08/18/2010] [Accepted: 09/17/2010] [Indexed: 01/13/2023] Open
Abstract
The heart and the kidneys share responsibility for maintaining hemodynamic stability and end-organ perfusion. Connections between these organs ensure that subtle physiologic changes in one system are tempered by compensation in the other through a variety of pathways and mediators. In the setting of underlying heart disease or chronic kidney disease, the capacity of each organ to respond to perturbation caused by the other may become compromised. This has recently led to the characterization of the cardiorenal syndrome (CRS). This review will primarily focus on CRS type 1 where acute decompensated heart failure (ADHF) results in activation of hemodynamic and neurohormonal factors leading to an acute drop in the glomerular filtration rate and the development of acute kidney injury. We will examine the scope and impact of this problem, the pathophysiology associated with this relationship, including underperfuson and venous congestion, diagnostic tools for earlier detection, and therapeutic interventions to prevent and treat this complication.
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Affiliation(s)
- Gautham Viswanathan
- Division of Nephrology, Tufts Medical Center, 800 Washington Street, P.O. 391, Boston, MA 02111, USA
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Bhuiyan S, Fukunaga K. Stimulation of Sigma-1 receptor by dehydroepiandrosterone ameliorates hypertension-induced kidney hypertrophy in ovariectomized rats. Exp Biol Med (Maywood) 2010; 235:356-64. [PMID: 20404054 DOI: 10.1258/ebm.2009.009177] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The incidence of chronic renal disease in women increases with aging, especially after menopause, suggesting that loss of sex hormones contributes to the development and progression of renal diseases. Recent studies revealed that decreased dehydroepiandrosterone (DHEA) levels are associated with endothelial dysfunction, renal injury and increased cardiovascular mortality in postmenopausal women. We here investigate the role of DHEA, also known as Sigma-1 receptor (Sigma-1R) agonist, on kidney injury induced by pressure overload (PO) after ovariectomy (OVX) and defined mechanisms underlying its protective action. Wistar rats subjected to bilateral OVX were further treated with abdominal aortic stenosis between the right and left renal arteries. DHEA (15 and 30 mg/kg) was administered orally once a day for 14 days starting from two weeks after aortic banding. Time course study indicated that the right kidney (RK) weight-to-body weight (BW) ratio increases time-dependently from one to four weeks along with increased mean arterial blood pressure (MABP) after banding in the abdominal aorta with no change in the left kidney (LK) weight-to-BW ratio. Similarly, we found significant time-dependent decrease in Sigma-1R expression in the RK with no changes in the LK. Administration of the Sigma-1R agonist, DHEA, significantly inhibited hypertension-induced increases in the RKW-to-BW ratio and increased expression of Sigma-1R in the RK. DHEA also attenuated PO-induced disturbance of heart rate and MABP. DHEA administration significantly restored PO-induced impaired endothelial nitric oxide synthase (eNOS) activity with concomitant increased phosphorylation of eNOS (Ser1179) and Akt activity with increased phosphorylation at Ser 473 and at Thr 308 in the RK. We here documented, for the first time, the potential role of Sigma-1R to protect the kidney from PO-induced injury in ovariectomized rats. DHEA administration protects hypertension-induced kidney injury via upregulation of Sigma-1R and stimulation of Akt-eNOS signaling in ovariectomized rats.
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Gökalp O, Özdem S, Dönmez S, Dogan M, Demirin H, Kara Y, Sütcü R, Cicek E, Özer MK, Delibas N. Impairment of endothelium-dependent vasorelaxation in cadmium-hypertensive rats. Toxicol Ind Health 2009; 25:447-53. [DOI: 10.1177/0748233709106822] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abnormalities in the production and/or release of relaxing factors from the endothelium have been implicated in the development of hypertension in several animal models. Endothelium-dependent relaxation has been reported to be impaired in thoracic aorta in experimentally induced and genetically hypertensive rats. Present study has extented these observations to thoracic aorta of cadmium-hypertensive rats. The possible role of alterations in oxidant status was also studied. Hypertension was induced by the intraperitoneal administration of 1 mg/kg/day cadmium for 15 days. Mechanical responses produced by acetylcholine (ACh, 10— 9—10—4 M) and sodium nitroprusside (SNP, 10—10—10— 5 M) were studied on phenylephrine-precontracted thoracic aorta rings from control and cadmium-hypertensive rats. Serum nitric oxide (NO) and aortic malondialdehyde (MDA) levels were measured. ACh-induced relaxation was attenuated in aorta from cadmium-hypertensive rats, whereas relaxation responses to SNP did not differ significantly between the groups. Exposure of aortic rings to NG-nitro-L-arginine methyl ester (L-NAME, 10 —4 M) resulted in a significantly greater inhibition of relaxation response to ACh in aortic rings of cadmium-hypertensive rats as compared with control rats. Incubation with L-arginine (L-Arg, 10 —3 M) caused a similar reversal of the inhibition of ACh-induced relaxation by L-NAME in both groups. Serum NO levels were decreased and aortic MDA levels were increased in cadmium-treated rats as compared with control rats. However, the differences between the groups did not reach a statistical significance. These findings suggested that the reduction in endothelium-dependent relaxation may play a role in cadmium-induced hypertension as it was in many other hypertension models.
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Affiliation(s)
- O. Gökalp
- Department of Pharmacology, School of Medicine, Dicle University, Diyarbakir, Turkey,
| | - S. Özdem
- Biochemistry Unit, Central Laboratory, School of Medicine, Akdeniz University, Antalya, Turkey
| | - S. Dönmez
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - M. Dogan
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - H. Demirin
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - Y. Kara
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - R. Sütcü
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - E. Cicek
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - MK Özer
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
| | - N. Delibas
- Department of Biochemistry, School of Medicine, Süleyman Demirel University, Isparta, Turkey
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Kemuriyama T, Tandai-Hiruma M, Kato K, Ohta H, Maruyama S, Sato Y, Nishida Y. Endogenous angiotensin II has fewer effects but neuronal nitric oxide synthase has excitatory effects on renal sympathetic nerve activity in salt-sensitive hypertension-induced heart failure. J Physiol Sci 2009; 59:275-81. [PMID: 19340531 PMCID: PMC10717097 DOI: 10.1007/s12576-009-0034-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2008] [Accepted: 02/19/2009] [Indexed: 10/20/2022]
Abstract
The effects of endogenous angiotensin II (Ang II) and neuronal nitric oxide synthase (nNOS) on tonic sympathetic activity were studied in salt-sensitive hypertension-induced heart failure. Dahl salt-sensitive rats were fed 8% NaCl diet for 9 weeks to induce chronic heart failure (CHF-DSS). The effects of intravenous administration of a selective nNOS inhibitor, S-methyl-L: -thiocitrulline (SMTC), and an Ang II type 1-receptor blocker, losartan, on renal sympathetic nerve activity (RSNA) were examined in chronically instrumented conscious rats. Baroreceptor (baro)-unloaded RSNA was obtained by decreasing arterial pressure with caval occlusion to determine tonic RSNA. SMTC significantly decreased baro-unloaded RSNA, and subsequent losartan recovered baro-unloaded RSNA to the control level in CHF-DSS rats. To compare the effects of the inhibitors between low- and high-activity states of the renin-angiotensin system (RAS), Sprague-Dawley rats were fed low (0.04%)- or high (8%)-salt diets. A significant difference was found in the effects of SMTC and/or losartan on RSNA between the high- and low-RAS states, which suggested that there is a difference in the effect of endogenous Ang II on RSNA between salt-induced and other-type heart failure. To examine the effects of heart failure on brain-tissue nNOS activity, we measured the activities of the diencephalon in heart-failure rats. Heart failure significantly suppressed diencephalon nNOS activity, which was significantly different from the results in salt-sensitive hypertension without heart failure. These results suggest that endogenous Ang II has fewer effects, but nNOS has excitatory effects on tonic RSNA in salt-sensitive hypertension-induced heart failure.
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Affiliation(s)
- Takehito Kemuriyama
- Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, Japan.
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Abstract
The epidemic of Type 2 diabetes, and the parallel rising incidence of end-stage renal disease, is progressively increasing worldwide. Kidney disease is one of the major chronic microvascular complications of diabetes, and both metabolic and haemodynamic perturbations participate in its development and progression towards end-stage renal disease. Hypertension and poor metabolic control seem to interact in causing the relentless decline in renal function seen in diabetic patients. Both high circulating glucose levels and increased glomerular capillary pressure act in conjunction in stimulating the different cellular pathways leading to kidney disease. It has been suggested that mechanical forces at the glomerular level may aggravate the metabolic insult by stimulating excessive cellular glucose uptake by up-regulating the facilitative GLUT-1 (glucose transporter-1). We propose the existence of a self-maintaining cellular mechanism whereby a haemodynamic stimulus on glomerular cells induces the up-regulation of GLUT-1, an event followed by greater glucose uptake and activation of intracellular metabolic pathways, resulting in excess TGF-beta1 (transforming growth factor-beta1) production. TGF-beta1, one of the major prosclerotic cytokines in diabetic kidney disease, maintains the up-regulation of GLUT-1, perpetuating a series of cellular events that result, as their ultimate effect, in increased extracellular matrix synthesis and altered permeability of the glomerular filtration barrier. Mechanical and metabolic coupling could represent an important mechanism of injury in the diabetic kidney.
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Abstract
Nitric oxide (NO) has multiple protective effects for regulating the cardiovascular and renal systems. The major functions include endothelium-dependent relaxation, anti-inflammatory effects, as well as antihypertrophic and antithrombotic activities. Many of the activities mediated by NO are systematically antagonized by angiotensin-II (Ang II), a vasconstrictor peptide. Studies described in the review below have demonstrated that the balance between NO and Ang II activities rather than the absolute concentration of each molecule determines their effects on the physiology and pathophysiology of the cardiovascular and renal systems. NO donors have been used for years as therapeutic agents for a range of cardiovascular conditions including angina, myocardial infarction and for the reduction of arterial stiffness. An understanding of the mechanisms underlying the effects of these medications will enable the development of novel therapies to balance the effects of NO in the cardiovascular system.
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Affiliation(s)
- Leopoldo Raij
- Nephrology/Hypertension Division, University of Miami, Veterans Affairs Medical Center, Miami, FL, USA.
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Abstract
OBJECTIVES Increased endothelial production of reactive oxygen species and decreased nitric oxide bioactivity, associated with the upregulation of monocyte chemoattractant protein (MCP)-1 and lectin-like oxidized low-density lipoprotein receptor (LOX)-1, link hypertension with atherogenesis. We investigated whether the beneficial effects of thiazide diuretics are exclusively related to a reduction in the biomechanical stress of hypertension or are also endowed with pleiotropic vasculoprotective effects that are independent of their effect upon blood pressure. METHODS Dahl salt-sensitive (DSS) rats, a paradigm of human salt-sensitive hypertension, were given a diet with normal salt (0.5% NaCl), high salt (4% NaCl), or a high salt diet plus either hydrochlorothiazide 75 mg/l, chlorthalidone 37 or 75 mg/l in their drinking water for 6 weeks. We determined systolic blood pressure (SBP), left ventricular hypertrophy (LVH), proteinuria, aortic superoxide anion (O2(-)) production, endothelium-dependent relaxation (EDR) to acetylcholine, and aortic angiotensin II type 1 (AT1) receptor, LOX-1, and MCP-1 messenger RNA expression (by real-time polymerase chain reaction). RESULTS DSS rats on a high salt diet developed hypertension, LVH, proteinuria, increased production of aortic O2(-) (106%), impaired EDR, and aortic upregulation of AT1 receptor (198%), LOX-1 (135%), and MCP-1 (145%). Hydrochlorothiazide as well as the high and low dose of chlorthalidone reduced SBP, LVH, and proteinuria, but did not reduce O2(-) production, AT1 receptor, LOX-1, or MCP-1 expression, or improved EDR. CONCLUSIONS This study demonstrates that thiazide diuretics do not reduce oxidative stress, improve endothelial function, or prevent the expression of pro-atherogenic molecules. We conclude that thiazide diuretics may not fully provide long-term global cardiovascular protection beyond lowering blood pressure.
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Mori T, Polichnowski A, Glocka P, Kaldunski M, Ohsaki Y, Liang M, Cowley AW. High perfusion pressure accelerates renal injury in salt-sensitive hypertension. J Am Soc Nephrol 2008; 19:1472-82. [PMID: 18417720 DOI: 10.1681/asn.2007121271] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Renal injury in the Dahl salt-sensitive rat mimics human salt-sensitive forms of hypertension that are particularly prevalent in black individuals, but the mechanisms that lead to the development of this injury are incompletely understood. We studied the impact of renal perfusion pressure (RPP) on the development of renal injury in this model. During the development of salt-induced hypertension over 2 wk, the RPP to the left kidney was maintained at control levels (125 +/- 2 mmHg) by continuous servocontrol inflation of an aortic balloon implanted between the renal arteries; during the same period, the RPP to the right kidney rose to 164 +/- 8 mmHg. After 2 wk of a 4% salt diet, DNA microarray and real-time PCR identified genes related to fibrosis and epithelial-to-mesenchymal transition in the kidneys exposed to hypertension. The increased RPP to the right kidney accounted for differences in renal injury between the two kidneys, measured by percentage of injured cortical and juxtamedullary glomeruli, quantified proteinaceous casts, number of ED-1-positive cells per glomerular tuft area, and interstitial fibrosis. Interlobular arteriolar injury was not increased in the kidney exposed to elevated pressure but was reduced in the control kidney. We conclude that elevations of RPP contribute significantly to the fibrosis and epithelial-to-mesenchymal transition found in the early phases of hypertension in the salt-sensitive rat.
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Affiliation(s)
- Takefumi Mori
- Department of Physiology, Medical College of Wisconsin, 8701 Watertown Plank Road, Milwaukee, WI 53226, USA
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Acetylsalicylic acid provides cerebrovascular protection from oxidant damage in salt-loaded stroke-prone rats. Life Sci 2008; 82:806-15. [DOI: 10.1016/j.lfs.2008.01.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2007] [Revised: 01/16/2008] [Accepted: 01/22/2008] [Indexed: 11/21/2022]
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Patterson ME, Mullins JJ, Mitchell KD. Renoprotective effects of neuronal NOS-derived nitric oxide and cyclooxygenase-2 metabolites in transgenic rats with inducible malignant hypertension. Am J Physiol Renal Physiol 2007; 294:F205-11. [PMID: 17977909 DOI: 10.1152/ajprenal.00150.2007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study was performed to determine the effects of neuronal nitric oxide synthase (nNOS) and cyclooxygenase-2 (COX-2) inhibition on blood pressure and renal hemodynamics in transgenic rats with inducible ANG II-dependent malignant hypertension [strain name: TGR(Cyp1a1Ren2)]. Male Cyp1a1-Ren2 rats (n = 7) were fed a normal diet containing indole-3-carbinol (I3C; 0.3%) for 6-9 days to induce malignant hypertension. Mean arterial pressure (MAP) and renal hemodynamics were assessed in pentobarbital sodium-anesthetized Cyp1a1-Ren2 rats before and during intravenous infusion of the nNOS inhibitor S-methyl-l-thiocitrulline (l-SMTC; 1 mg/h). In hypertensive Cyp1a1-Ren2 rats, l-SMTC increased MAP from 169 +/- 3 to 188 +/- 4 mmHg (P < 0.01), which was a smaller increase than in noninduced rats (124 +/- 9 to 149 +/- 9 mmHg, P < 0.01, n = 5). Additionally, l-SMTC decreased renal plasma flow (RPF) to a similar extent (-34 +/- 13 vs. -35 +/- 12%) in the hypertensive and normotensive rats (4.1 +/- 0.2 to 2.7 +/- 0.5 and 3.1 +/- 0.3 to 2.0 +/- 0.3 ml x min(-1) x g(-1), respectively, P < 0.01) but did not alter glomerular filtration rate (GFR) in either group. In additional experiments, administration of the COX-2 inhibitor, nimesulide (3 mg/kg i.v.), during simultaneous infusion of l-SMTC decreased MAP in both hypertensive and noninduced rats (182 +/- 2 to 170 +/- 3 mmHg and 153 +/- 3 to 140 +/- 3 mmHg, respectively, P < 0.01). Nimesulide also decreased RPF (1.9 +/- 0.2 to 0.8 +/- 0.1 ml x min(-1) x g(-1), P < 0.01) and GFR (0.9 +/- 0.1 to 0.4 +/- 0.1 ml x min(-1) x g(-1), P < 0.01) in hypertensive rats but did not alter RPF or GFR in noninduced rats. The present findings demonstrate that both nNOS-derived NO and COX-2 metabolites exert pronounced renal vasodilator influences in hypertensive Cyp1a1-Ren2 rats. The data also indicate that the renal vasodilator effects of COX-2-derived prostanoids in hypertensive Cyp1a1-Ren2 rats are not dependent on nNOS activity.
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Affiliation(s)
- Matthew E Patterson
- Department of Physiology, Tulane University Health Sciences Center, New Orleans, LA 70112, USA
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Gnudi L, Thomas SM, Viberti G. Mechanical forces in diabetic kidney disease: a trigger for impaired glucose metabolism. J Am Soc Nephrol 2007; 18:2226-32. [PMID: 17634438 DOI: 10.1681/asn.2006121362] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Nephropathy is one of the major microvascular complications of diabetes, and both hemodynamic and metabolic stimuli participate in its development and progression toward ESRD. There is now a greater understanding of the molecular pathways that are activated by high glomerular capillary pressure and hyperglycemia and how they interplay to produce kidney pathology. The observation that overexpression of glucose transporter 1 (GLUT-1) in mesangial cells could induce a "diabetic cellular phenotype" has led to the postulation that the expression of GLUT-1 could be upregulated in glomeruli that are exposed to high pressure. This review suggests a mechanism by which mechanical forces may aggravate a metabolic insult by stimulating excessive cellular glucose uptake. Proposed is the existence of a self-maintaining cycle whereby a hemodynamic stimulus on glomerular cells induces GLUT-1 overexpression followed by greater glucose uptake and activation of intracellular glucose metabolic pathways, resulting in excess TGF-beta1 production. TGF-beta1 in turn, maintains overexpression of GLUT-1, perpetuating a signaling sequence that has, as its ultimate effect, increased extracellular matrix synthesis. This mechanical and metabolic coupling suggests a novel pathophysiologic mechanism of injury in the kidney in diabetes and possibly other glomerular diseases.
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Affiliation(s)
- Luigi Gnudi
- Cardiovascular Division, King's College London, Guy's Hospital, London SE1 9RT, UK.
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Namikoshi T, Tomita N, Fujimoto S, Haruna Y, Ohzeki M, Komai N, Sasaki T, Yoshida A, Kashihara N. Isohumulones Derived from Hops Ameliorate Renal Injury via an Anti-Oxidative Effect in Dahl Salt-Sensitive Rats. Hypertens Res 2007; 30:175-84. [PMID: 17460388 DOI: 10.1291/hypres.30.175] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Previous studies have reported that isohumulones, the bitter compounds in beer, improve insulin resistance and hyperlipidemia in several animal models. In this study, we examined whether isohumulones ameliorate renal injury. Dahl salt-sensitive hypertensive rats were fed a low-salt diet (LS), a high-salt diet (HS) or a high-salt diet containing 0.3% isohumulones (HS+IH) for 4 weeks. Urinary nitrite/nitrate (NOx) excretion was measured at 4 weeks along with blood pressure and urinary protein excretion. Renal injury was evaluated histologically and reactive oxygen species (ROS) and nitric oxide (NO) production in the renal cortex was visualized. Oxidative stress and NO synthase (NOS) expression were evaluated by immunohistochemical staining and Western blot analysis. Mean blood pressure was significantly decreased in the HS+IH group compared with the HS group at 4 weeks (158.1+/-8.7 vs. 177.5+/-3.7 mmHg; p<0.05). Isohumulones prevented the development of proteinuria in the HS+IH group compared with the HS group at 2 weeks (61.7+/-26.8 vs. 117.2+/-9.8 mg/day; p<0.05). Glomerulosclerosis and interstitial fibrosis scores were significantly decreased in the HS+IH group compared with the HS group (0.61+/-0.11 vs. 1.55+/-0.23, 23.7+/-6.8 vs. 36.1+/-3.5%; p<0.05 for both). In the HS group, increased ROS and decreased NO were observed in glomeruli in vivo. Isohumulones reduced the ROS production, leading to the restoration of bioavailable NO. Urinary NOx excretion was significantly increased in the HS+IH group compared with the HS group. Furthermore, renal nitrotyrosine was increased in the HS group compared with the LS group, and this effect was prevented by isohumulones. Renal NOS expression did not differ among the three groups. These results suggest that isohumulones may prevent the progression of renal injury caused by hypertension via an anti-oxidative effect.
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Affiliation(s)
- Tamehachi Namikoshi
- Division of Nephrology, Department of Internal Medicine, Kawasaki Medical School, Japan
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Hollenberg NK. Organ systems dependent on nitric oxide and the potential for nitric oxide-targeted therapies in related diseases. J Clin Hypertens (Greenwich) 2006; 8:63-73. [PMID: 17170607 PMCID: PMC8109608 DOI: 10.1111/j.1524-6175.2006.06042.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nitric oxide (NO) is a universal messenger molecule that plays diverse and essential physiologic roles in multiple organ systems, including the vasculature, bone, muscle, heart, kidney, liver, and central nervous system. NO is produced by 3 known isoforms-endothelial, neuronal, and inducible NO synthase-each of which perform distinct functions. Impairment of NO bioactivity may be an important factor in the pathogenesis of a wide range of conditions, including preeclampsia, osteoporosis, nephropathy, liver disease, and neurodegenerative diseases. Although increased levels of NO synthase or NO bioactivity have been associated with some of these disease states, research increasingly suggests that preservation or promotion of normal NO bioactivity may be beneficial in reducing the risks and perhaps reversing the underlying pathophysiology. Based on this rationale, studies investigating the use of NO-donating or NO-promoting agents in some of these diseases have produced positive results, at least to some degree, in either animal or human studies. Further investigation of NO-targeted therapies in these diverse diseases is clearly mandated.
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Affiliation(s)
- Norman K Hollenberg
- Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, MA 02115, USA.
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Bai Y, Ye S, Mortazavi R, Campese V, Vaziri ND. Effect of renal injury-induced neurogenic hypertension on NO synthase, caveolin-1, AKt, calmodulin and soluble guanylate cyclase expressions in the kidney. Am J Physiol Renal Physiol 2006; 292:F974-80. [PMID: 17122386 DOI: 10.1152/ajprenal.00157.2006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Single injection of a small quantity of phenol into the cortex of one kidney in rats results in development of persistent hypertension (HTN) which is thought to be mediated by activation of renal afferent and efferent sympathetic pathways and sodium retention. Nitric oxide (NO) plays a major role in regulation of renal vascular resistance, tubular Na(+) reabsorption, pressure natriuresis, and thereby systemic arterial pressure. The present study was performed to test the hypothesis that chronic renal injury-induced HTN may be associated with dysregulation of NO system in the kidney. Accordingly, urinary NO metabolite (NO(x)) and cGMP excretions as well as renal cortical tissue (right kidney) expressions of NO synthase (NOS) isoforms [endothelial, neuronal, and inducible NOS, respectively (eNOS, nNOS, and iNOS)], NOS-regulatory factors (Caveolin-1, phospho-AKt, and calmodulin), and second-messenger system (soluble guanylate cyclase [sGC] and phosphodiesterase-5 [PDE-5]) were determined in male Sprague-Dawley rats 4 wk after injection of phenol (50 mul of 10% phenol) or saline into the lower pole of left kidney. The phenol-injected group exhibited a significant elevation of arterial pressure, marked reductions of urinary NO(x) and cGMP excretions, downregulations of renal tissue nNOS, eNOS, Phospho-eNOS, iNOS, and alpha chain of sGC. However, renal tissue AKt, phospho-AKT, Calmodulin, and PDE-5 proteins were unchanged in the phenol-injected animals. In conclusion, renal injury in this model results in significant downregulations of NOS isoforms and sGC and consequent reductions of NO production and cGMP generation by the kidney, events that may contribute to maintenance of HTN in this model.
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Affiliation(s)
- Y Bai
- Division of Nephrology and Hypertension, University of California, Irvine, CA 92868, USA
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Van Dijk SJ, Specht PAC, Lazar J, Jacob HJ, Provoost AP. Synergistic QTL interactions between Rf-1 and Rf-3 increase renal damage susceptibility in double congenic rats. Kidney Int 2006; 69:1369-76. [PMID: 16541022 DOI: 10.1038/sj.ki.5000301] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The FHH (fawn-hooded hypertensive) rat is a model of hypertension-associated chronic kidney damage. Five interacting quantitative trait loci (QTLs), named Rf-1-Rf-5, determine the high renal susceptibility. The aim of the present study was to investigate a possible interaction between Rf-1 and Rf-3. Differences in renal susceptibility between ACI (August x Copenhagen Irish) controls, Rf-1A and Rf-3 single congenics, and Rf-1A+3 double congenic rats were assessed using four different treatments: two-kidney control (2K), 2K plus N(omega)-nitro-L-arginine methyl ester (L-NAME)-induced hypertension (2K+L-NAME), unilateral nephrectomy (UNX), and UNX plus L-NAME-induced hypertension (UNX+L-NAME). Proteinuria (UPV) and systolic blood pressure (SBP) were assessed after 6, 12, and 18 weeks, while the incidence of glomerulosclerosis (%FGS) was determined at the end of the experiment. In a separate experiment, renal autoregulation was assessed in 13-15-week old 2K rats of all four strains. Compared to ACI rats, small increases in renal susceptibility were found in Rf-1A and Rf-3 single congenics following 2K+L-NAME, UNX, and UNX+L-NAME treatments. However, in the Rf-1A+3 double congenics, a major increase in renal susceptibility was found with all four treatments. Both Rf-1A and Rf-1A+3 congenic rats had an impaired renal autoregulation. In contrast, the Rf-3 had a normal autoregulation, similar to that of the ACI rat. These findings indicate that Rf-1 and Rf-3 alone slightly increase the susceptibility to the development of renal damage. However, a synergistic interaction between these two QTLs markedly enhances renal susceptibility. In contrast to the Rf-1 region, the Rf-3 region does not carry genes influencing renal autoregulation.
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Affiliation(s)
- S J Van Dijk
- Department of Pediatric Surgery, Erasmus MC, Rotterdam, The Netherlands
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Abstract
Nephropathy is a major diabetic microvascular complication; both metabolic and hemodynamic perturbations play critical roles in its occurrence and progression toward end-stage renal disease. Improvements in metabolic and blood pressure control have been shown to confer protection from this diabetic complication. In this article, we review the facilitative glucose transporter Glut-1, its regulation, and its potential role in linking metabolic and hemodynamic perturbations in the pathophysiologic processes that lead to kidney injury in diabetes. We propose that an auto-maintaining mechanism of hemodynamic perturbations and increased tissue angiotensin II may be involved in the initiation and maintenance of a loop in which transforming growth factor beta1 and Glut-1 upregulation play important roles in the pathophysiology of diabetic-induced kidney lesions. The understanding of the molecular mechanisms that link glomerular hypertension and excessive glucose metabolism may provide insight into new therapeutic strategies for the treatment of diabetic renal disease.
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Affiliation(s)
- Luigi Gnudi
- Department of Diabetes and Endocrinology, Cardiovascular Division, King's College London, 5th floor Thomas Guy House, Guy's Hospital, St Thomas Street, London SE1 9RT, UK.
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Llorens S, Salazar FJ, Nava E. Assessment of the nitric oxide system in the heart, aorta and kidney of aged Wistar-Kyoto and spontaneously hypertensive rats. J Hypertens 2005; 23:1507-14. [PMID: 16003177 DOI: 10.1097/01.hjh.0000173122.31848.f3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To assess the nitric oxide (NO) system in the cardiovascular and renal systems of old Wistar-Kyoto (WKY) rats and old spontaneously hypertensive rats (SHR) compared with young rats of the same strains. DESIGN AND METHODS The NO pathway was assessed: (i) in analytical studies measuring the concentration of nitrate in plasma and the activity of NO synthases in the left ventricle, renal cortex and renal medulla; and (ii) in functional studies, in which we measured the blood pressure effects of NO blockade with intravenous N-nitro-L-arginine methyl ester (L-NAME, 0.1 mg/kg) in anaesthetized rats. In addition, we studied NO production in the aorta comparing the force attained by isolated segments exposed to cumulative concentrations of L-NAME (10(-7)-10(-3) mol/l). RESULTS Plasma nitrate was significantly higher in old rats of both strains. Calcium-dependent NO synthase activity was markedly upregulated in the left ventricle, renal cortex and renal medulla of the old rats, both in hypertensive and normotensive animals. Intravenous L-NAME elicited deeper pressor effects in the old rats of either blood pressure condition. Aortic segments from old WKY rats, but not those from SHR, achieved remarkably stronger tension in response to L-NAME compared with the young counterparts. CONCLUSIONS These findings suggest that the NO system is upregulated in the cardiovascular system and the kidney in senescence, even in hypertension.
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Affiliation(s)
- Silvia Llorens
- Department of Medical Sciences, University of Castilla-La Mancha and Centro Regional de Investigaciones Biomédicas, Albacete, Spain
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Van Dijk SJ, Specht PAC, Lazar J, Jacob HJ, Provoost AP. Renal Damage Susceptibility and Autoregulation in Rf-1 and Rf-5 Congenic Rats. ACTA ACUST UNITED AC 2005; 101:e59-66. [PMID: 15976509 DOI: 10.1159/000086417] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Accepted: 03/04/2005] [Indexed: 11/19/2022]
Abstract
BACKGROUND Linkage analyses of crosses of rats susceptible to renal damage, fawn-hooded hypertensive (FHH), and those resistant to kidney damage, August x Copenhagen Irish (ACI), indicated that five quantitative trait loci (QTLs), Rf-1 to Rf-5, influence proteinuria (UPV), albuminuria (UAV) and focal glomerulosclerosis (FGS). Here we present data obtained in congenic rats to directly assess the role of the Rf-1 and Rf-5 QTLs. METHODS Renal damage (UPV, UAV, and FGS) was assessed in ACI, ACI.FHH-(D1Rat324-D1Rat156)(Rf-1B), and ACI.FHH-(D17Rat117-D17Arb5)(D17Rat180-D17Rat51) (Rf-5) congenic rats in the two-kidney (2K) control situation, and following L-NAME-induced hypertension, unilateral nephrectomy (UNX), and UNX combined with L-NAME. In addition we investigated renal blood flow (RBF) autoregulation in 2K congenic and parental ACI and FHH rats. RESULTS Compared to ACI, Rf-1B congenic rats showed a significant increase in susceptibility to renal damage after all three treatments. The increase was most pronounced after UNX with L-NAME. In contrast, the degree of renal damage in Rf-5 congenic rats was not different from the ACI. Like FHH, Rf-1B rats had impaired renal autoregulation. In contrast, RBF autoregulation of Rf-5 rats does not differ from ACI. CONCLUSION The Rf-5 QTL does not show any direct effect. The Rf-1 QTL carries one or more genes impairing renal autoregulation and influencing renal damage susceptibility. Whether these are the same genes remains to be established.
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Affiliation(s)
- Sabine J Van Dijk
- Department of Pediatric Surgery, Erasmus Medical Center, Rotterdam, The Netherlands.
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Tandai-Hiruma M, Horiuchi J, Sakamoto H, Kemuriyama T, Hirakawa H, Nishida Y. Brain neuronal nitric oxide synthase neuron-mediated sympathoinhibition is enhanced in hypertensive Dahl rats. J Hypertens 2005; 23:825-34. [PMID: 15775788 DOI: 10.1097/01.hjh.0000163152.27954.7a] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To elucidate the role of central neurons containing neuronal nitric oxide synthase (nNOS neurons) in the sympathetic nervous system in hypertensive Dahl salt-sensitive (DS) rats. DESIGN AND METHODS Dahl rats were fed either a regular-salt (0.4% NaCl) or high-salt (8% NaCl) diet for 4 weeks. The effect of intracerebroventricular administration of S-methyl-L-thiocitrulline, a selective nNOS inhibitor, on renal sympathetic nerve activity was examined in chronically instrumented conscious DS rats. The activity and protein amount of brain nNOS was evaluated by enzyme assay and western blot analysis. The distribution and number of nNOS neurons in the brainstem were examined immunohistochemically in hypertensive and normotensive DS rats. RESULTS S-methyl-L-thiocitrulline induced a larger increase in tonic renal sympathetic nerve activity generated before baroreflex-mediated inhibition in hypertensive DS rats than normotensive DS rats. Hypertensive DS rats showed increased nNOS activity in the brainstem, but not in the diencephalon or cerebellum. High nNOS activity was confirmed by an increase in the amount of nNOS protein. nNOS Neurons were localized in several nuclei throughout the brainstem; the dorsolateral periaqueductal gray, pedunculopontine tegmental nucleus, dorsal raphe nucleus, laterodorsal tegmental nucleus, lateral parabrachial nucleus, rostral ventrolateral medulla, nucleus tractus solitarius and raphe magnus. The number of nNOS neurons in these nuclei, except for the two raphes, was significantly greater in hypertensive than in normotensive DS rats. CONCLUSIONS These findings suggest that central nNOS-mediated sympathoinhibition may be enhanced in salt-sensitive hypertensive Dahl rats. The upregulated nNOS-mediated inhibition may occur in the central sympathetic control system generated before baroreflex-mediated inhibition.
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Affiliation(s)
- Megumi Tandai-Hiruma
- Department of Physiology II, National Defense Medical College, Tokorozawa, Saitama, Japan.
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Buikema H. Activation of calcium-activated potassium channels by ghrelin: an opportunity to study the (patho)physiological role(s) of endothelium-derived hyperpolarizing factor? J Hypertens 2005; 23:713-5. [PMID: 15775772 DOI: 10.1097/01.hjh.0000163136.51717.8f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Teran FJ, Johnson RA, Stevenson BK, Peyton KJ, Jackson KE, Appleton SD, Durante W, Johnson FK. Heme oxygenase-derived carbon monoxide promotes arteriolar endothelial dysfunction and contributes to salt-induced hypertension in Dahl salt-sensitive rats. Am J Physiol Regul Integr Comp Physiol 2005; 288:R615-22. [PMID: 15528397 DOI: 10.1152/ajpregu.00123.2004] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular tissues express heme oxygenase (HO), which metabolizes heme to form carbon monoxide (CO). Heme-derived CO inhibits nitric oxide synthase and promotes endothelium-dependent vasoconstriction. After 4 wk of high-salt diet, Dahl salt-sensitive (Dahl-S) rats display hypertension, increased vascular HO-1 expression, and attenuated vasodilator responses to ACh that can be completely restored by acute treatment with an inhibitor of HO. In this study, we examined the temporal development of HO-mediated endothelial dysfunction in isolated pressurized first-order gracilis muscle arterioles, identified the HO product responsible, and studied the blood pressure effects of HO inhibition in Dahl-S rats on a high-salt diet. Male Dahl-S rats (5–6 wk) were placed on high-salt (8% NaCl) or low-salt (0.3% NaCl) diets for 0–4 wk. Blood pressure increased gradually, and responses to an endothelium-dependent vasodilator, ACh, decreased gradually with the length of high-salt diet. Flow-induced dilation was abolished in hypertensive Dahl-S rats. Acute in vitro pretreatment with an inhibitor of HO, chromium mesoporphyrin (CrMP), restored endothelium-dependent vasodilation and abolished the differences between groups. The HO product CO prevented the restoration of endothelium-dependent dilation by CrMP. Furthermore, administration of an HO inhibitor lowered blood pressure in Dahl-S rats with salt-induced hypertension but did not do so in low-salt control rats. These results suggest that hypertension and HO-mediated endothelial dysfunction develop gradually and simultaneously in Dahl-S rats on high-salt diets. They also suggest that HO-derived CO underlies the impaired endothelial dysfunction and contributes to hypertension in Dahl-S rats on high-salt diets.
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Affiliation(s)
- Federico J Teran
- Dept. of Physiology, Tulane University Health Sciences Center, 1430 Tulane Avenue, SL39, New Orleans, LA 70112, USA
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McCarty MF. Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. Med Hypotheses 2005; 64:854-63. [PMID: 15694707 DOI: 10.1016/j.mehy.2003.11.043] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2003] [Accepted: 11/21/2003] [Indexed: 01/19/2023]
Abstract
Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure; production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells; as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe Street, San Diego, CA 92109, USA.
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Johnson FK, Johnson RA, Peyton KJ, Durante W. Arginase inhibition restores arteriolar endothelial function in Dahl rats with salt-induced hypertension. Am J Physiol Regul Integr Comp Physiol 2004; 288:R1057-62. [PMID: 15591155 DOI: 10.1152/ajpregu.00758.2004] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular tissues express arginase that metabolizes L-arginine to L-ornithine and urea and thus reduces substrate availability for nitric oxide formation. Dahl salt-sensitive (Dahl-S) rats with salt-induced hypertension show endothelial dysfunction, including decreased vascular nitric oxide formation. This study tests the hypothesis that increased vascular arginase activity contributes to endothelial dysfunction in hypertensive Dahl-S rats. Male Dahl-S rats (5-6 wk) were placed on high (8%) or low (0.3%) NaCl diets for 4 wk. With respect to the low-salt group, mean arterial blood pressure was increased in the high-salt animals. Immunohistochemical stainings for arginase I and II were enhanced in arterioles isolated from high-salt Dahl-S rats. Experiments used isolated Krebs buffer-superfused first-order gracilis muscle arterioles with constant pressure (80 mmHg) and no luminal flow or constant midpoint but altered endpoint pressures to establish graded levels of luminal flow (0-50 microl/min). In high-salt arterioles, responses to an endothelium-dependent vasodilator acetylcholine (1 nmol/l to 3 micromol/l) and flow-induced dilation were decreased. Acute in vitro treatment with an inhibitor of arginase, 100 micromol/l (S)-(2-boronoethyl)-L-cystine, or the nitric oxide precursor, 1 mmol/l L-arginine, similarly enhanced acetylcholine and flow-induced maximal dilations and abolished the differences between high- and low-salt arterioles. These data show that arteriolar arginase expression is increased and that endothelium-dependent vasodilation is decreased in high-salt Dahl-S rats. Acute pretreatment with an arginase inhibitor or with L-arginine restores endothelium-dependent vasodilation and abolishes the differences between high- and low-salt groups. These results suggest that enhanced vascular arginase activity contributes to endothelial dysfunction in Dahl-S rats with salt-induced hypertension and identifies arginase as a potential therapeutic target to prevent endothelial dysfunction.
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Affiliation(s)
- Fruzsina K Johnson
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University Health Sciences Center, New Orleans, Louisiana, USA
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Affiliation(s)
- Leopoldo Raij
- Nephrology-Hypertension Division, Veterans Affairs Medical Center and University of Miami School of Medicine, Miami, Florida 33125, USA.
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McCarty MF. Marinobufagenin may mediate the impact of salty diets on left ventricular hypertrophy by disrupting the protective function of coronary microvascular endothelium. Med Hypotheses 2004; 62:993-1002. [PMID: 15142663 DOI: 10.1016/j.mehy.2003.11.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2003] [Accepted: 11/11/2003] [Indexed: 01/06/2023]
Abstract
Individuals who eat salty diets and who are "salt-sensitive" tend to have increased left ventricular mass, independent of blood pressure; this phenomenon awaits an explanation. It is clear that local up-regulation of angiotensin II (AngII) production and activity play a key role in the induction of left ventricular hypertrophy (LVH). Recent evidence suggests that a healthy coronary microvascular endothelium opposes this effect by serving as a paracrine source of nitric oxide (NO), a natural antagonist of AngII activity, and that up-regulation of this mechanism can account for the protective role of bradykinin with respect to LVH. The coronary microvasculature also possesses NAD(P)H oxidase activity that can generate superoxide, inimical to the bioactivity of endothelial NO. There is now good reason to believe that the triterpenoid marinobufagenin (MBG), a selective inhibitor of the alpha-1 isoform of the sodium pump, mediates the impact of salty diets on blood pressure;production of MBG by the adrenal cortex is boosted when salt-sensitive animals are fed salty diets. It is hypothesized that coronary microvascular endothelium expresses the alpha-1 isoform of the sodium pump, and that MBG thus can target this endothelium. If that is the case, MBG would be expected to decrease membrane potential in these cells;as a consequence, superoxide production would be up-regulated, NO synthase activity would be down-regulated, and myocardial NO bioactivity would thus be suppressed. This would offer a satisfying explanation for the impact of salt and salt-sensitivity on risk for LVH. If expression of the alpha-1 isoform of the sodium pump is a more general property of vascular endothelium, MBG may suppress NO bioactivity in other regions of the vascular tree, thereby contributing to other adverse effects elicited by salty diets: reduced arterial compliance, medial hypertrophy, impaired endothelium-dependent vasodilation, hypertensive/diabetic glomerulopathy, increased risk for stroke, and hypertension.
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Affiliation(s)
- Mark F McCarty
- Pantox Laboratories, 4622 Santa Fe Street, San Diego, CA 92109, USA.
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Johnson FK, Durante W, Peyton KJ, Johnson RA. Heme oxygenase-mediated endothelial dysfunction in DOCA-salt, but not in spontaneously hypertensive, rat arterioles. Am J Physiol Heart Circ Physiol 2004; 286:H1681-7. [PMID: 14693679 DOI: 10.1152/ajpheart.00409.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular heme oxygenase (HO) metabolizes heme to form carbon monoxide. Carbon monoxide inhibits nitric oxide synthase and promotes endothelium-dependent vasoconstriction. We reported HO-1-mediated endothelial dysfunction in Dahl salt-sensitive hypertension. Previous studies suggested that salt-sensitive hypertensive rats, but not spontaneously hypertensive rats (SHR), display endothelial dysfunction. This study examines the hypothesis that HO-1-mediated arteriolar endothelial dysfunction develops in deoxycorticosterone acetate (DOCA)-salt hypertensive (DOCA) rats, but not in SHR. Uninephrectomized (isoflurane anesthesia) male Sprague-Dawley rats received DOCA injections and saline drinking solution for 4 wk. Rats subjected to sham surgery received vehicle injections and tap water. Blood pressure was elevated in DOCA rats and SHR compared with sham and Wistar-Kyoto (WKY) groups. Aortic HO-1 expression and blood carboxyhemoglobin levels were elevated in the DOCA group, but not in SHR. In isolated gracilis muscle arterioles, ACh caused concentration-related vasodilation in all groups, with attenuated maximum responses in DOCA, but not in SHR, arterioles. Acute pretreatment with an inhibitor of HO, chromium mesoporphyrin, restored ACh-induced responses in DOCA arterioles to sham levels. ACh responses remained the same in SHR and WKY arterioles after chromium mesoporphyrin treatment. These data show that HO-1 levels and activity are increased and arteriolar responses to ACh are decreased in DOCA rats, but not in SHR. Furthermore, in DOCA arterioles, an inhibitor of HO restores ACh-induced vasodilation to sham levels. These results suggest that elevated HO-1 levels and activity, not resulting from hypertension per se, contribute to endothelial dysfunction in DOCA rats.
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Affiliation(s)
- Fruzsina K Johnson
- Tulane Hypertension and Renal Center of Excellence, Department of Physiology, Tulane University Health Sciences Center, New Orleans, Louisiana 70112, USA.
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Fernández AP, Serrano J, Castro S, Salazar FJ, López JC, Rodrigo J, Nava E. Distribution of nitric oxide synthases and nitrotyrosine in the kidney of spontaneously hypertensive rats. J Hypertens 2003; 21:2375-88. [PMID: 14654759 DOI: 10.1097/00004872-200312000-00027] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
OBJECTIVES To study the cellular distribution and the expression of the major isoforms of NO synthase (NOS) and of nitrotyrosine in the kidney in spontaneous hypertension. DESIGN AND METHODS We have studied by immunohistochemistry the location of the endothelial (eNOS), neuronal (nNOS) and inducible (iNOS) isoforms and nitrotyrosine in kidney slices from normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) using specific antibodies. In order to quantify the expression of these proteins, we have analyzed dissected renal cortical and medullary sections by means of Western blot. RESULTS Tubular cells were immunoreactive to nNOS and more numerous in the renal medulla of the SHR compared with that of the WKY, specifically in the outer medulla and the papillary region. Western blot also showed higher expression of nNOS in the renal medulla, but not the renal cortex of the SHR. In contrast, iNOS and eNOS distribution and expression were similar in the kidneys of WKY rats and SHR. Immunohistochemistry showed immunoreactive cells to nitrotyrosine in a variety of renal cells similarly distributed in SHR and WKY kidneys. Western analysis detected three proteins of 14.5, 23.7 and 39 kDa immunoreactive to nitrotyrosine, showing a higher expression in the renal cortex compared to the renal medulla. CONCLUSIONS The expression of nNOS is higher in the renal medulla of the SHR, and the distribution of eNOS, iNOS and nitrotyrosine is similar in SHR and WKY rats. It is proposed that the higher expression of the neuronal isoform in the medullary tubular cells is a protective mechanism aimed to improve renal function in spontaneous hypertension.
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Cowley AW, Mori T, Mattson D, Zou AP. Role of renal NO production in the regulation of medullary blood flow. Am J Physiol Regul Integr Comp Physiol 2003; 284:R1355-69. [PMID: 12736168 DOI: 10.1152/ajpregu.00701.2002] [Citation(s) in RCA: 134] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The unique role of nitric oxide (NO) in the regulation of renal medullary function is supported by the evidence summarized in this review. The impact of reduced production of NO within the renal medulla on the delivery of blood to the medulla and on the long-term regulation of sodium excretion and blood pressure is described. It is evident that medullary NO production serves as an important counterregulatory factor to buffer vasoconstrictor hormone-induced reduction of medullary blood flow and tissue oxygen levels. When NO synthase (NOS) activity is reduced within the renal medulla, either pharmacologically or genetically [Dahl salt-sensitive (S) rats], a super sensitivity to vasoconstrictors develops with ensuing hypertension. Reduced NO production may also result from reduced cellular uptake of l-arginine in the medullary tissue, resulting in hypertension. It is concluded that NO production in the renal medulla plays a very important role in sodium and water homeostasis and the long-term control of arterial pressure.
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Affiliation(s)
- Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, USA.
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Chiba Y, Ando K, Fujita T. The protective effects of taurine against renal damage by salt loading in Dahl salt-sensitive rats. J Hypertens 2002; 20:2269-74. [PMID: 12409966 DOI: 10.1097/00004872-200211000-00027] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
OBJECTIVES We evaluated whether taurine prevents renal damage which is accompanied with enhanced expression of lectin-like oxidized low-density lipoprotein (OxLDL) receptor-1 (LOX-1) mRNA, in salt-loaded Dahl salt-sensitive (DS) rats. METHODS Male, 4-week-old DS rats were fed on either a high-salt (8% NaCl) or normal-salt (0.66% NaCl) diet for 4 weeks. Some DS rats with high-salt diet were given drinking water containing 1% taurine. We evaluated blood pressure, renal function, renal LOX-1 expression and parameters for oxidative stress. RESULTS In salt-loaded DS rats, there was a significant increase in heart weight and urinary protein, accompanied with enhanced LOX-1 expression in kidney. All of these were reduced by concomitant supplementation of taurine, although both antihypertensive and antihyperlipidemic effects of taurine were only slight in salt-loaded DS rats. On the other hand, salt-induced increment in urinary 8-hydroxy-deoxyguanosine, a parameter of oxidative damage, was completely normalized by taurine supplementation. CONCLUSIONS The protective effects of taurine supplementation against renal damage induced by salt loading in DS rats may be attributed to the suppression of LOX-1, probably through its antioxidant effects.
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Affiliation(s)
- Yuko Chiba
- Department of Internal Medicine, University of Tokyo, School of Medicine, Tokyo, Japan
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Zhou XJ, Vaziri ND, Zhang J, Wang HW, Wang XQ. Association of renal injury with nitric oxide deficiency in aged SHR: prevention by hypertension control with AT1 blockade. Kidney Int 2002; 62:914-21. [PMID: 12164873 DOI: 10.1046/j.1523-1755.2002.00516.x] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Aged spontaneously hypertensive rats (SHR) develop end-stage renal disease resembling that of uncontrolled essential hypertension in humans. Nitric oxide (NO) and angiotensin II (Ang II) play an important role in the regulation of blood pressure and the growth of vascular smooth muscle and renal mesangial cells. The relationship between renal NO system, Ang II activity and renal injury in aged SHR is not fully understood. METHODS The 8-week-old SHR were randomized into losartan-treated (30 mg/kg/day for 55 weeks) and vehicle treated groups. The age-matched Wistar-Kyoto rats (WKY) served as controls. Renal histology and tissue expressions of endothelial and inducible NO synthases (eNOS and iNOS) and nitrotyrosine were examined at 63-weeks of age. RESULTS Compared to the WKY group, untreated SHR showed severe hypertension, proteinuria, renal insufficiency, a twofold decrease in renal tissue eNOS and iNOS expressions and massive nitrotyrosine accumulation. This was associated with severe glomerulosclerosis, tubular atrophy and interstitial fibrosis. Losartan therapy normalized blood pressure, prevented proteinuria and renal insufficiency, abrogated the fall in renal eNOS and iNOS protein contents, mitigated renal nitrotyrosine accumulation, and prevented the histological abnormalities found in the untreated SHR. CONCLUSIONS Aged SHR exhibit severe renal lesions with acquired NO deficiency that are prevented by hypertension control with AT1 blockade. These findings point to the possible role of NO deficiency in the pathogenesis of renal lesions in aged SHR.
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Affiliation(s)
- Xin Joseph Zhou
- Department of Pathology, Division of Renal Pathology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9073, USA.
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Meng S, Roberts LJ, Cason GW, Curry TS, Manning RD. Superoxide dismutase and oxidative stress in Dahl salt-sensitive and -resistant rats. Am J Physiol Regul Integr Comp Physiol 2002; 283:R732-8. [PMID: 12185008 DOI: 10.1152/ajpregu.00346.2001] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The roles of oxidative stress and renal superoxide dismutase (SOD) levels and their association with renal damage were studied in Dahl salt-sensitive (S) and salt-resistant (R)/Rapp strain rats during changes in Na intake. After 3 wk of a high (8%)-Na diet in S rats, renal medullary Cu/Zn SOD was 56% lower and Mn SOD was 81% lower than in R high Na-fed rats. After 1, 2, and 3 wk of high Na, urinary excretion of F(2)-isoprostanes, an index of oxidative stress, was significantly greater in S rats compared with R rats. Plasma F(2)-isoprostane concentration increased in the 2-wk S high Na-fed group. After 3 wk, renal cortical and medullary superoxide production was significantly increased in Dahl S rats on high Na intake, and urinary protein excretion, an index of renal damage, was 273 +/- 32 mg/d in S high Na-fed rats and 35 +/- 4 mg/d in R high Na-fed rats (P < 0.05). In conclusion, salt-sensitive hypertension in the S rat is accompanied by marked decreases in renal medullary SOD and greater renal oxidative stress and renal damage than in R rats.
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Affiliation(s)
- Shumei Meng
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi 39216, USA
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Adler S, Huang H. Impaired regulation of renal oxygen consumption in spontaneously hypertensive rats. J Am Soc Nephrol 2002; 13:1788-94. [PMID: 12089374 DOI: 10.1097/01.asn.0000019781.90630.0f] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Abnormalities of nitric oxide (NO) and oxygen radical synthesis and of oxygen consumption have been described in the spontaneously hypertensive rat (SHR) and may contribute to the pathogenesis of hypertension. NO plays a role in the regulation of renal oxygen consumption in normal kidney, so the response of renal cortical oxygen consumption to stimulators of NO production before and after the addition of the superoxide scavenging agent tempol (4-hydroxy-2,2,6,6-tetramethyl piperidine-1-oxyl) was studied. Baseline cortical oxygen consumption was similar in SHR and Wistar-Kyoto (WKY) rats (SHR: 600 +/- 55 nmol O(2)/min per g, WKY: 611 +/- 51 nmol O(2)/min per g, P > 0.05). Addition of bradykinin, enalaprilat, and amlodipine decreased oxygen consumption significantly less in SHR than WKY (SHR: bradykinin -13.9 +/- 1.9%, enalaprilat -15.3 +/- 1.6%, amlodipine -11.9 +/- 0.7%; WKY: bradykinin -22.8 +/- 1.0%, enalaprilat -24.1 +/- 2.0%, amlodipine -20.7 +/- 2.3%; P < 0.05), consistent with less NO effect in SHR. Addition of tempol reversed the defects in responsiveness to enalaprilat and amlodipine, suggesting that inactivation of NO by superoxide contributes to decreased NO availability. The response to an NO donor was similar in both groups and was unaffected by the addition of tempol. These results demonstrate that NO availability in the kidney is decreased in SHR, resulting in increased oxygen consumption. This effect is due to enhanced production of superoxide in SHR. By lowering intrarenal oxygen levels, reduced NO may contribute to susceptibility to injury and renal fibrosis. Increasing NO production, decreasing oxidant stress, or both might prevent these changes by improving renal oxygenation.
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Affiliation(s)
- Stephen Adler
- Department of Medicine, Division of Nephrology, New York Medical College, 19 Bradhurst Avenue, Suite 0100, Hawthorne, NY 10532, USA.
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Zhang L, Kosaka H. Sex-specific acute effect of estrogen on endothelium-derived contracting factor in the renal artery of hypertensive Dahl rats. J Hypertens 2002; 20:237-46. [PMID: 11821708 DOI: 10.1097/00004872-200202000-00013] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To determine whether estrogen rapidly affects endothelium-derived contracting factor (EDCF) in the renal artery of hypertensive Dahl rats, and whether factors other than nitric oxide (NO) contribute to the effect of estrogen. DESIGN Acute effects of estrogen on the acetylcholine-induced vasomotor responses and on prostaglandin H2/thromboxane A2 mimetic, U46619,-induced contraction were examined in isolated arterial rings. METHODS AND RESULTS Dahl salt-sensitive male and female rats were fed an 8% NaCl diet for 4 weeks. The blood pressure increased more rapidly and to a greater extent in males than in females. Renal arterial rings were prepared for isometric tension recording. 17beta-Estradiol, but not the biologically less active stereoisomer, 17alpha-estradiol, improved the relaxation response to acetylcholine in renal arteries from females. Estrogen also rapidly decreased the contraction evoked by acetylcholine (10(-6) to approximately 10(-4) mol/l) in renal arteries from females and it was effective at a physiological concentration (10(-9) mol/l) in the presence of Nomega-nitro-l-arginine methyl ester (an NO synthase inhibitor). The estrogen receptor antagonist, ICI 182,780, abolished the effect of estrogen, whereas the cytochrome P450 inhibitor, miconazole, had no effect. The contraction induced by U46619 was also suppressed by estrogen, without any contribution from NO. Estrogen had no effect on either relaxation or contraction responses in renal arteries from males. CONCLUSION 17beta-Estradiol antagonizes increases in vascular tone in hypertensive females by enhancing NO-dependent relaxation, and by suppressing EDCF-mediated mechanisms in an NO-independent manner.
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Affiliation(s)
- Ling Zhang
- The Second Department of Physiology, Kagawa Medical University, Kagawa 761-0793, Japan
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