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Tang M, Hu J, Li W, Zhang N, Ning S, Yan Y, Cui Z. Effects of Renal Denervation on Ouabain-Induced Hypertension in Rats. Int J Hypertens 2024; 2024:4763189. [PMID: 38957519 PMCID: PMC11217579 DOI: 10.1155/2024/4763189] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Revised: 05/04/2024] [Accepted: 05/28/2024] [Indexed: 07/04/2024] Open
Abstract
Background Ouabain, a Na+, K+-ATPase inhibitor, is elevated in hypertensive patients. Evidence suggests ouabain contributes to hypertension mainly through activation of the sympathetic nervous system (SNS). Renal nerves play a vital role in the regulation of SNS activity, so we hypothesize that renal denervation may attenuate the development of ouabain-induced hypertension. Methods and Results Forty Sprague-Dawley rats were divided into following groups (n = 10 each): control group (sham surgery plus intraperitoneal saline injection), RDN group (renal denervation (RDN) plus intraperitoneal saline injection), ouabain group (sham surgery plus intraperitoneal ouabain injection), and ouabain + RDN group (RDN plus intraperitoneal ouabain injection). After eight weeks, compared with the control group, rats in the ouabain group exhibited elevated blood pressure (P < 0.05), increased plasma epinephrine, norepinephrine, angiotensin II, and aldosterone levels (P < 0.05). These indexes could be significantly ameliorated by RDN. RDN also reduced the thickening of aortic tunica media and downregulated the expression of proliferating cell nuclear antigen (PCNA) in the thoracic aorta induced by ouabain. Masson staining and echocardiography showed that myocardial fibrosis and increased left ventricular mass in the ouabain group could be attenuated by RDN. Conclusions The present study reveals that renal nerves play an important role in the development of ouabain-induced hypertension. RDN could inhibit the pressor effect and the myocardial remodeling induced by ouabain potentially via inhibiting catecholamine release and vascular smooth muscle cell proliferation. Clinical studies are needed to explore whether RDN may exhibit better antihypertensive effects on hypertensive patients with high plasma ouabain levels as compared to those with normal plasma ouabain levels.
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Affiliation(s)
- Minna Tang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China
| | - Jialu Hu
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China
| | - Wenshu Li
- School of Public Health, Fudan University, Shanghai, 200032, China
| | - Ningzhi Zhang
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China
| | - Sisi Ning
- Department of Cardiology, Shanghai Changning Tianshan Traditional Chinese Medicine Hospital, Shanghai 200051, China
| | - Yan Yan
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China
| | - Zhaoqiang Cui
- Department of Cardiology, Zhongshan Hospital, Fudan University, Shanghai Institute of Cardiovascular Diseases, Shanghai, China
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Abdelmissih S, Sayed WM, Rashed LA, Kamel MM, Eshra MA, Attallah MI, El-Naggar RAR. The extent of involvement of ouabain, hippocampal expression of Na+/K+-ATPase, and corticosterone/melatonin receptors ratio in modifying stress-induced behavior differs according to the stressor in context. Braz J Med Biol Res 2022; 55:e11938. [PMID: 35857994 PMCID: PMC9296128 DOI: 10.1590/1414-431x2022e11938] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2021] [Accepted: 04/18/2022] [Indexed: 11/21/2022] Open
Abstract
The aim of this study was to assess the effect of two types of stressors,
regarding the extent of involvement of ouabain (OUA), hippocampal
sodium/potassium ATPase (NKA) expression, and the hippocampal
corticosterone receptors (CR)/melatonin receptors
(MR) expression ratio, on the behavioral and cardiovascular
responses and on the hippocampal cornu ammonis zone 3 (CA3) and dentate gyrus
(DG). Thirty adult male Wistar albino rats aged 7-8 months were exposed to
either chronic immobilization or a disturbed dark/light cycle and treated with
either ouabain or vehicle. In the immobilized group, in the absence of
hippocampal corticosterone (CORT) changes, rats were non-responsive to stress,
despite experiencing increased pulse rate, downregulated hippocampal
sodium/potassium pump, and enhanced hippocampal CR/MR
expression ratio. Prolonged darkness precipitated a reduced upright attack
posture, with elevated CORT against hippocampal MR
downregulation. Both immobilization and, to a lesser extent, prolonged darkness
stress resulted in histopathological and ultrastructural neurodegenerative
changes in the hippocampus. OUA administration did not change the behavioral
resilience in restrained rats, despite persistence of the underlying biochemical
derangements, added to decreased CORT. On the contrary, with exposure to short
photoperiods, OUA reverted the behavior towards a combative reduction of
inactivity, with unvaried CR/MR and CORT, while ameliorating
hippocampal neuro-regeneration, with co-existing NKA and
MR repressions. Therefore, the extent of OUA, hippocampal
NKA expression, and CR/MR expression, and
subsequent behavioral and cardiac responses and hippocampal histopathology,
differ according to the type of stressor, whether immobilization or prolonged
darkness.
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Affiliation(s)
- S Abdelmissih
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - W M Sayed
- Department of Anatomy and Embryology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - L A Rashed
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M M Kamel
- Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt.,Department of Basic Medical Science, Faculty of Medicine, King Salman International University, South Sinai, Egypt
| | - M A Eshra
- Department of Physiology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - M I Attallah
- Department of Medical Pharmacology, Faculty of Medicine, Kasr Al-Ainy, Cairo University, Cairo, Egypt
| | - R A-R El-Naggar
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Misr University for Science and Technology, Giza, Egypt
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Liu C, Gao J, Cui X, Li Z, Chen L, Yuan Y, Zhang Y, Mei L, Zhao L, Cai D, Hu M, Zhou B, Li Z, Qin T, Si H, Li G, Lin Z, Xu Y, Zhu C, Yin Y, Zhang C, Xu W, Li Q, Wang K, Gilbert MTP, Heller R, Wang W, Huang J, Qiu Q. A towering genome: Experimentally validated adaptations to high blood pressure and extreme stature in the giraffe. SCIENCE ADVANCES 2021; 7:7/12/eabe9459. [PMID: 33731352 PMCID: PMC7968835 DOI: 10.1126/sciadv.abe9459] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Accepted: 02/02/2021] [Indexed: 05/02/2023]
Abstract
The suite of adaptations associated with the extreme stature of the giraffe has long interested biologists and physiologists. By generating a high-quality chromosome-level giraffe genome and a comprehensive comparison with other ruminant genomes, we identified a robust catalog of giraffe-specific mutations. These are primarily related to cardiovascular, bone growth, vision, hearing, and circadian functions. Among them, the giraffe FGFRL1 gene is an outlier with seven unique amino acid substitutions not found in any other ruminant. Gene-edited mice with the giraffe-type FGFRL1 show exceptional hypertension resistance and higher bone mineral density, both of which are tightly connected with giraffe adaptations to high stature. Our results facilitate a deeper understanding of the molecular mechanism underpinning distinct giraffe traits, and may provide insights into the study of hypertension in humans.
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Affiliation(s)
- Chang Liu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Jianbo Gao
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - Xinxin Cui
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zhipeng Li
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China
| | - Lei Chen
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yuan Yuan
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yaolei Zhang
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
| | - Liangwei Mei
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China
| | - Lan Zhao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Xi'an 710069, China
| | - Dan Cai
- BGI-Qingdao, BGI-Shenzhen, Qingdao 266555, China
| | - Mingliang Hu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Botong Zhou
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Zihe Li
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Tao Qin
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Huazhe Si
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China
| | - Guangyu Li
- College of Animal Science and Technology, Jilin Agricultural University, Changchun 130118, China
| | - Zeshan Lin
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yicheng Xu
- Jiaxing SynBioLab. Co. Ltd., Jiaxing 314000, China
| | - Chenglong Zhu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yuan Yin
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Chenzhou Zhang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Wenjie Xu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Qingjie Li
- Research Center of Traditional Chinese Medicine, The Affiliated Hospital to Changchun University of Chinese Medicine, Changchun 130021, China
| | - Kun Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - M Thomas P Gilbert
- Center for Evolutionary Hologenomics, GLOBE Institute, University of Copenhagen, Øster Voldgade 5-7, Copenhagen 1350, Denmark
- Norwegian University of Science and Technology, University Museum, 7491 Trondheim, Norway
| | - Rasmus Heller
- Section for Computational and RNA Biology, Department of Biology, University of Copenhagen, Copenhagen N 2200, Denmark.
| | - Wen Wang
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China.
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650223, China
| | - Jinghui Huang
- Department of Orthopaedics, Xijing Hospital, The Fourth Military Medical University, Xi'an 710032, China.
| | - Qiang Qiu
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China.
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4
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Chronic ouabain treatment induces Rho kinase activation. Arch Pharm Res 2015; 38:1897-905. [PMID: 25860025 DOI: 10.1007/s12272-015-0597-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Accepted: 04/02/2015] [Indexed: 01/21/2023]
Abstract
Ouabain is an endogenous Na(+)/K(+)-ATPase inhibitor whose chronic administration induces hypertension. Endogenous ouabain levels increase in human essential hypertension. On the other hand, Rho/Rho kinase (ROCK) pathway has been implicated in various animal models of hypertension. In the current work, we evaluated the possible involvement of Rho kinase in ouabain-induced hypertension. Ouabain was administered daily (20 µg/kg, i.p.) to Wistar rats for 6 weeks. After the ouabain treatment, we evaluated the possible changes in vascular responses to KCl and phenylephrine alone and in the presence of Rho kinase inhibitor Y27632. We also determined the expressions of ROCKs, Rho A and phosphorylation of myosin binding subunit of myosin light chain phosphatase (pMYPT) and activation of Rho A. Agonist-induced contractions in the presence of Y27632 are significantly decreased and Y27632-induced relaxations in aortas precontracted with phenylephrine are significantly enhanced with the chronic treatment of ouabain. Although the expressions of ROCK I and ROCK II remained unchanged, pMYPT expression was significantly increased in ouabain-treated group. Moreover, Rho A expression and activation were decreased after treatment with ouabain. Although Rho kinase expression did not change in aortas, increased basal Rho kinase activation may contribute to the development of ouabain-induced hypertension. Our current data present the first evidence that Rho kinase is involved in the development of ouabain-induced hypertension in rats.
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Ghadhanfar E, Al-Bader M, Turcani M. Wistar rats resistant to the hypertensive effects of ouabain exhibit enhanced cardiac vagal activity and elevated plasma levels of calcitonin gene-related peptide. PLoS One 2014; 9:e108909. [PMID: 25279791 PMCID: PMC4184851 DOI: 10.1371/journal.pone.0108909] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Accepted: 08/28/2014] [Indexed: 01/03/2023] Open
Abstract
Ouabain is a cardiac glycoside produced in the adrenal glands and hypothalamus. It affects the function of all cells by binding to Na+/K+-ATPase. Several lines of evidence suggest that endogenous ouabain could be involved in the pathogenesis of essential (particularly, salt-sensitive) hypertension. However, information regarding the postulated hypertensive effect of the long-term administration of low-dose exogenous ouabain is inconsistent. This study was designed to help settle this controversy through the use of telemetric monitoring of arterial blood pressure and to elucidate the ouabain-induced alterations that could either promote or prevent hypertension. Ouabain (63 and 324 µg/kg/day) was administered subcutaneously to male Wistar rats. Radiotelemetry was used to monitor blood pressure, heart rate and measures of cardiovascular variability and baroreflex sensitivity. The continuous administration of ouabain for 3 months did not elevate arterial blood pressure. The low-frequency power of systolic pressure variability, urinary excretion of catecholamines, and cardiovascular response to restraint stress and a high-salt diet as well as the responsiveness to α1-adrenergic stimulation were all unaltered by ouabain administration, suggesting that the activity of the sympathetic nervous system was not increased. However, surrogate indices of cardiac vagal nerve activity based on heart rate variability were elevated. Molecular remodeling in mesenteric arteries that could support the development of hypertension (increased expression of the genes for the Na+/Ca2+ exchanger and Na+/K+-ATPase α2 isoform) was not evident. Instead, the plasma level of vasodilatory calcitonin gene-related peptide (CGRP) significantly rose from 55 (11, SD) in the control group to 89 (20, SD) pg/ml in the ouabain-treated rats (PTukey's = 18.10(-5)). These data show that long-term administration of exogenous ouabain does not necessarily cause hypertension in rodents. The augmented parasympathetic activity and elevated plasma level of CGRP could be linked to the missing hypertensive effect of ouabain administration.
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Affiliation(s)
- Elham Ghadhanfar
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Maie Al-Bader
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
| | - Marian Turcani
- Department of Physiology, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait
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7
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Zhao SH, Gao HQ, Ji X, Wang Y, Liu XJ, You BA, Cui XP, Qiu J. Effect of ouabain on myocardial ultrastructure and cytoskeleton during the development of ventricular hypertrophy. Heart Vessels 2012; 28:101-13. [PMID: 22241736 DOI: 10.1007/s00380-011-0219-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Accepted: 12/08/2011] [Indexed: 02/03/2023]
Abstract
The aim of this work is to study cytoskeletal impairment during the development of ouabain-induced ventricular hypertrophy. Male Sprague-Dawley rats were treated with either ouabain or saline. Systolic blood pressure (SBP) was recorded weekly. At the end of the 3rd and 6th week, the rats were killed and cardiac mass index were measured. Hematoxylin-eosin and Sirius red staining were carried out and cardiac ultrastructure were studied using transmission electron microscopy. The mRNA level of Profilin-1, Desmin, PCNA, TGF-β(1) and ET-1 in the left ventricle were measured using real-time quantitative PCR while their protein levels were examined by Western blot or immunohistochemistry. After 3 weeks, there was no significant difference in the mean SBP, cardiac mass index, mRNA and protein expression of PCNA, TGF-β(1) and ET-1 between the two groups. However, ouabain-treated rats showed disorganized cardiac cytoskeleton with abnormal expression of Profilin-1 and Desmin. After 6 weeks, the cardiac mass index remained the same in the two groups while PCNA, TGF-β(1), and ET-1 have been upregulated in ouabain-treated rats. The cardiac cytoskeletal impairment was more severe in ouabain-treated rats with further changes of Profilin-1 and Desmin. Cytoskeletal abnormality is an ultra-early change during ouabain-induced ventricular hypertrophy, before the release of hypertrophic factors. Therapy for prevention of ouabain-induced hypertrophy should start at the early stage by preventing the cytoskeleton from disorganization.
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Affiliation(s)
- Shao-hua Zhao
- Department of Geriatric Cardiology, Qilu Hospital of Shandong University, 107 Wenhua Xi Road, Jinan, People's Republic of China
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Zhang YR, Yuan ZY. Dopamine-mediated inhibition of renal Na+/K+-ATPase in HK-2 cells is reduced by ouabain. Clin Exp Pharmacol Physiol 2010; 37:613-8. [PMID: 20132239 DOI: 10.1111/j.1440-1681.2010.05364.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
1. Abnormal renal sodium handling is considered a major contributing factor in hypertension associated with chronic ouabain treatment. However, the molecular mechanisms involved in abnormal renal sodium handling have not been elucidated. Therefore, we investigated whether chronic ouabain treatment perturbs dopamine D(1) receptor function. 2. The expression and phosphorylation levels of the D(1) receptor in cells of the human proximal tubule cell line (HK-2) were determined using western blot analysis and reverse transcription polymerase chain reaction. The activity of the renal sodium/potassium pump (Na(+)/K(+)-ATPase) was measured using a colourimetric assay, and cyclic adenosine monophosphate accumulation was determined by performing a radioimmunoassay. 3. We showed that chronic ouabain treatment decreased the protein and mRNA expression levels of the D(1) receptor and increased the basal phosphorylation of the D(1) receptor in HK-2 cells. We also showed that in the presence of ouabain, HK-2 cells did not reveal the cyclic adenosine monophosphate accumulation and Na(+)/K(+)-ATPase inhibition induced by the D(1) receptor agonist fenoldopam. 4. We hypothesize that the ouabain-induced decrease in renal D(1) receptor function is responsible for the increase in renal sodium reabsorption, which eventually leads to ouabain-induced hypertension.
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Affiliation(s)
- Yu-Rong Zhang
- Department of Cardiovascular Medicine, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, Shaanxi 710061, China
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9
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Effects of long-term ouabain treatment on blood pressure, sodium excretion, and renal dopamine D1 receptor levels in rats. J Comp Physiol B 2009; 180:117-24. [DOI: 10.1007/s00360-009-0391-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2009] [Revised: 06/25/2009] [Accepted: 06/29/2009] [Indexed: 01/11/2023]
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Lynn KS, Li LL, Lin YJ, Wang CH, Sheng SH, Lin JH, Liao W, Hsu WL, Pan WH. A neural network model for constructing endophenotypes of common complex diseases: an application to male young-onset hypertension microarray data. ACTA ACUST UNITED AC 2009; 25:981-8. [PMID: 19237446 PMCID: PMC2666815 DOI: 10.1093/bioinformatics/btp106] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Motivation: Identification of disease-related genes using high-throughput microarray data is more difficult for complex diseases as compared with monogenic ones. We hypothesized that an endophenotype derived from transcriptional data is associated with a set of genes corresponding to a pathway cluster. We assumed that a complex disease is associated with multiple endophenotypes and can be induced by their up/downregulated gene expression patterns. Thus, a neural network model was adopted to simulate the gene–endophenotype–disease relationship in which endophenotypes were represented by hidden nodes. Results: We successfully constructed a three-endophenotype model for Taiwanese hypertensive males with high identification accuracy. Of the three endophenotypes, one is strongly protective, another is weakly protective and the third is highly correlated with developing young-onset male hypertension. Sixteen of the involved 101 genes were highly and consistently influential to the endophenotypes. Identification of SLC4A5, SLC5A10 and LDOC1 indicated that sodium/bicarbonate transport, sodium/glucose transport and cell-proliferation regulation may play important upstream roles and identification of BNIP1, APOBEC3F and LDOC1 suggested that apoptosis, innate immune response and cell-proliferation regulation may play important downstream roles in hypertension. The involved genes not only provide insights into the mechanism of hypertension but should also be considered in future gene mapping endeavors. Availability: Microarray data and test program are available at http://ms.iis.sinica.edu.tw/microarray/index.htm Contact:pan@ibms.sinica.edu.tw or hsu@iis.sinica.edu.tw Supplementary information:Supplementary data are available at Bioinformatics online.
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Affiliation(s)
- Ke-Shiuan Lynn
- Institute of Information Sciences, Academia Sinica, Taipei, Taiwan
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11
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Jiang X, Ren YP, Lv ZR. Ouabain induces cardiac remodeling in rats independent of blood pressure. Acta Pharmacol Sin 2007; 28:344-52. [PMID: 17302996 DOI: 10.1111/j.1745-7254.2007.00496.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To investigate the ouabain's effects on cardiac remodeling in rats. METHODS Male Sprague-Dawley rats were treated with ouabain. Systolic blood pressure (SBP) was recorded weekly. After 4 and 6 weeks, echocardiography were performed, hemodynamic parameters were measured by invasive cardiac catheterization, changes in cardiac ultrastructure were analyzed using transmission electron microscopy, the collagen fraction of the left ventricle was assessed with Picrosirius red stain, and RT-PCR was applied to evaluate the mRNA level of myosin heavy chain-alpha and -beta in the left ventricle. RESULTS Having been treated with ouabain for 4 weeks, there was no significant difference in the mean SBP of the two groups. However, left ventricular hypertrophy, myocardial ultrastructure deterioration, and extracellular matrix remodeling were induced by ouabain treatment; meanwhile, cardiac systolic and diastolic performance were both worsened. Moreover, the cardiac MHC-beta mRNA was upregulated by ouabain treatment, whereas MHC-alpha mRNA was downregulated. After 4 weeks, the mean SBP in the ouabain group began to increase and was significantly higher than that in control group after 6 weeks (P<0.01); the rats'cardiac structure and function were worsened. CONCLUSION These results suggested that ouabain induces alterations in cardiac structure and function, and the effects happened before the increase of blood pressure. The results indicated that ouabain induced cardiac remodeling in rats independent of blood pressure.
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Affiliation(s)
- Xing Jiang
- Geriatric-Cardiovascular Department, the People Hospital of Shaanxi Province and the Third Hospital of Xi'an Jiaotong University, Xi'an 710068, China.
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12
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Silva E, Gomes P, Soares-da-Silva P. Overexpression of Na(+)/K (+)-ATPase parallels the increase in sodium transport and potassium recycling in an in vitro model of proximal tubule cellular ageing. J Membr Biol 2007; 212:163-75. [PMID: 17334838 DOI: 10.1007/s00232-005-7017-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2005] [Revised: 05/11/2006] [Indexed: 11/26/2022]
Abstract
Na(+)/K(+)-ATPase plays a key role in the transport of Na(+) throughout the nephron, but ageing appears to be accompanied by changes in the regulation and localization of the pump. In the present study, we examined the effect of in vitro cell ageing on the transport of Na(+) and K(+) ions in opossum kidney (OK) cells in culture. Cells were aged by repeated passing, and Na(+)/K(+)-ATPase activity and K(+) conductance were evaluated using electrophysiological methods. Na(+)K(+)-ATPase alpha(1)- and beta(1)-subunit expression was quantified by Western blot techniques. Na(+)/H(+) exchanger activity, changes in membrane potential, cell viability, hydrogen peroxide production and cellular proliferation were determined using fluorimetric assays. In vitro cell ageing is accompanied by an increase in transepithelial Na(+) transport, which results from an increase in the number of Na(+)/K(+)-ATPase alpha(1)- and beta(1)-subunits, in the membrane. Increases in Na(+)/K(+)-ATPase activity were accompanied by increases in K(+) conductance as a result of functional coupling between Na(+)/K(+)-ATPase and basolateral K(+) channels. Cell depolarization induced by both KCl and ouabain was more pronounced in aged cells. No changes in Na(+)/H(+) exchanger activity were observed. H(2)O(2) production was increased in aged cells, but exposure for 5 days to 1 and 10 microM: of H(2)O(2) had no effect on Na(+)/K(+)-ATPase expression. Ouabain (100 nM: ) increased alpha(1)-subunit, but not beta(1)-subunit, Na(+)/K(+)-ATPase expression in aged cells only. These cells constitute an interesting model for the study of renal epithelial cell ageing.
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Affiliation(s)
- E Silva
- Faculty of Medicine, Institute of Pharmacology and Therapeutics, 4200-319 , Porto, Portugal
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Ren YP, Huang RW, Lü ZR. Ouabain at pathological concentrations might induce damage in human vascular endothelial cells. Acta Pharmacol Sin 2006; 27:165-72. [PMID: 16412265 DOI: 10.1111/j.1745-7254.2006.00244.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
AIM To examine the time- and dose-dependent effects of ouabain on human umbilical vein endothelial cells (HUVEC) in vivo, and the changes in aortic endothelium and the different expression levels of Kv4.2 in vitro. METHODS The proliferation of HUVEC and cell death were determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, the incorporation of [3H]TdR, trypan blue staining, and lactate dehydrogenase (LDH) release. The response of endothelial cells to ouabain was explored with a complementary DNA microarray and a candidate gene was found. Ouabain-sensitive hypertensive rats were established by chronic administration of ouabain. Changes in the aortic endothelium were observed by electron microscopy, and the expression level of Kv4.2 in different animals was studied by using real-time quantitative reverse transcription-polymerase chain reaction (RT-PCR). RESULTS Ouabain stimulated the proliferation of HUVEC at physiological concentrations (0.3-0.9 nmol/L). Ouabain at pathological concentrations (0.9-1.8 nmol/L) inhibited proliferation and induced cell death. mRNA profile analysis indicated that 340 genes were differentially expressed after ouabain treatment: 145 were upregulated, of which 6 were upregulated significantly, including KCND2 (encoding the potassium voltage-gated channel shal-related subfamily member 2). The upregulated genes were mainly related to cell metabolism and transcription. In ouabain-sensitive hypertensive rats, the aortic endothelium was damaged and Kv4.2 (coded by KCND2) was over-expressed. CONCLUSION The physiological role of ouabain in HUVEC might involve the control of growth and metabolism. Ouabain at pathological concentrations might affect the structure and function of the vascular endothelium by modification of expression of the KCND2 gene, and participate vascular remodeling in hypertension.
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Affiliation(s)
- Yan-ping Ren
- Geriatric-Cardiovascular Department, First Hospital of Xi-an Jiaotong University, Xi-an 710061, China.
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Sakuma Y, Nonoguchi H, Takayama M, Yang T, Terada Y, Inoue T, Nakayama Y, Kohda Y, Sasaki S, Tomita K. Differential effects of hyperosmolality on Na-K-ATPase and vasopressin-dependent cAMP generation in the medullary thick ascending limb and outer medullary collecting duct. Hypertens Res 2006; 28:671-9. [PMID: 16392772 DOI: 10.1291/hypres.28.671] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Hyperosmolality in the renal medullary interstitium is generated by the renal countercurrent multiplication system, in which the medullary thick ascending limb (MAL) and the outer medullary collecting duct (OMCD) primarily participate. Since arginine vasopressin (AVP) regulates Na-K-ATPase activity directly via protein kinase A and indirectly via hyperosmolality, we investigated the acute and chronic effects of hyperosmolality on Na-K-ATPase and AVP-dependent cAMP generation in the MAL and OMCD. Microdissected MAL and OMCD from control and dehydrated rats were used for the measurement of Na-K-ATPase activity, mRNA expression of alpha-1, beta-1, and beta-2 subunits of Na-K-ATPase, and AVP-dependent cAMP generation. Na-K-ATPase activity in the MAL from dehydrated rats, as measured in isotonic medium, was higher than that of control rats. Moreover, incubation of samples in hypertonic medium (490 mOsm/kg H2O) further increased Na-K-ATPase activity. Dehydration increased alpha-1, beta-1, and beta-2 mRNA expression in the MAL without changing that in the OMCD. Western blot analysis revealed that in the outer medulla, the expression of beta-1, but not that of alpha-1 or beta-2, was stimulated by dehydration. Incubation of MAL or OMCD in hypertonic medium increased AVP-dependent cAMP generation. Higher levels of AVP-dependent cAMP were generated in the MAL from dehydrated rats than that of controls, although incubation in hypertonic medium did not lead to additional increases in AVP-dependent cAMP accumulation. In contrast, AVP-dependent cAMP generation in the OMCD was stimulated by dehydration, and was further stimulated by incubation in hypertonic medium. These findings demonstrate that Na-K-ATPase is upregulated short- and long-term hyperosmolality in the MAL, but not in OMCD.
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Affiliation(s)
- Yoriko Sakuma
- Department of Nephrology, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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Echevarria-Lima J, de Araújo EG, de Meis L, Rumjanek VM. Ca2+ mobilization induced by ouabain in thymocytes involves intracellular and extracellular Ca2+ pools. Hypertension 2003; 41:1386-92. [PMID: 12732588 DOI: 10.1161/01.hyp.0000072801.90600.c2] [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: 11/16/2022]
Abstract
Immune dysfunction has been reported in hypertensive rats, and circulating levels of ouabain are increased in some experimental models of hypertension. Ouabain is an inhibitor of the Na+/K+-ATPase capable of diverse effects on cells of the immune system, but its mode of action on these cells is still unknown. The levels of cytoplasmic calcium ions play an important role in cell signaling, and ouabain may induce an increase in intracellular calcium indirectly through the Na+/Ca2+ exchanger. The current work examined the possibility that this drug could be exerting its effects on thymocytes through calcium mobilization and an increase in the cytosolic calcium concentration. Intracellular calcium was evaluated by using Balb-c mouse thymocytes loaded with FURA-2. Both intracellular and extracellular calcium pools were mobilized by ouabain (3 to 1000 nmol). The influx of extracellular calcium depended on the Na+/Ca2+ exchanger and on voltage-dependent calcium channels, as it was inhibited by amiloride and benzamil, consistent with the inhibition of the Na+/K+ pump. In addition, the increase of calcium from intracellular stores was extremely rapid. Furthermore, an increase in cytosolic calcium levels was obtained with the combination of ouabain and thapsigargin, which was greater than that seen with either drug alone. Our data suggest that low concentrations of ouabain may be acting on thymocytes through a mechanism different from the traditional inhibition of the Na+/K+-ATPase, as the cytosolic calcium rise was partly dependent on the release from intracellular stores.
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Affiliation(s)
- Juliana Echevarria-Lima
- Laboratório de Imunologia Tumoral, Departamento de Bioquímica Médica, Universidade Federal do Rio de Janeiro, Brazil
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