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Kitada K, Nishiyama A. Potential Role of the Skin in Hypertension Risk Through Water Conservation. Hypertension 2024; 81:468-475. [PMID: 37942635 DOI: 10.1161/hypertensionaha.123.20700] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2023]
Abstract
Previous basic and clinical investigations have identified various pathogenic factors and determinants of risk that contribute to hypertension. Nevertheless, the pathogenesis of hypertension has not been fully elucidated. Moreover, despite the availability of antihypertensive medications for the management of blood pressure, treatments that address the full spectrum of the pathophysiological defects underpinning hypertension remain to be identified. To further investigate the mechanisms of primary hypertension, it is imperative to consider novel potential aspects, such as fluid management by the skin, in addition to the conventional risk factors. There is a close association between body fluid regulation and blood pressure, and the kidney, which, as the principal organ responsible for body fluid homeostasis, is the primary target for research in the field of hypertension. In addition, the skin functions as a biological barrier, potentially contributing to body fluid regulation. In this review, we propose the hypothesis that changes in skin water conservation are associated with hypertension risk based on recent findings. Further studies are required to clarify whether this novel hypothesis is limited to specific hypertension or applies to physiological blood pressure regulation.
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Affiliation(s)
- Kento Kitada
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Japan
| | - Akira Nishiyama
- Department of Pharmacology, Faculty of Medicine, Kagawa University, Japan
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2
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Ameer OZ. Hypertension in chronic kidney disease: What lies behind the scene. Front Pharmacol 2022; 13:949260. [PMID: 36304157 PMCID: PMC9592701 DOI: 10.3389/fphar.2022.949260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Accepted: 09/26/2022] [Indexed: 12/04/2022] Open
Abstract
Hypertension is a frequent condition encountered during kidney disease development and a leading cause in its progression. Hallmark factors contributing to hypertension constitute a complexity of events that progress chronic kidney disease (CKD) into end-stage renal disease (ESRD). Multiple crosstalk mechanisms are involved in sustaining the inevitable high blood pressure (BP) state in CKD, and these play an important role in the pathogenesis of increased cardiovascular (CV) events associated with CKD. The present review discusses relevant contributory mechanisms underpinning the promotion of hypertension and their consequent eventuation to renal damage and CV disease. In particular, salt and volume expansion, sympathetic nervous system (SNS) hyperactivity, upregulated renin–angiotensin–aldosterone system (RAAS), oxidative stress, vascular remodeling, endothelial dysfunction, and a range of mediators and signaling molecules which are thought to play a role in this concert of events are emphasized. As the control of high BP via therapeutic interventions can represent the key strategy to not only reduce BP but also the CV burden in kidney disease, evidence for major strategic pathways that can alleviate the progression of hypertensive kidney disease are highlighted. This review provides a particular focus on the impact of RAAS antagonists, renal nerve denervation, baroreflex stimulation, and other modalities affecting BP in the context of CKD, to provide interesting perspectives on the management of hypertensive nephropathy and associated CV comorbidities.
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Affiliation(s)
- Omar Z. Ameer
- Department of Pharmaceutical Sciences, College of Pharmacy, Alfaisal University, Riyadh, Saudi Arabia
- Department of Biomedical Sciences, Faculty of Medicine, Macquarie University, Sydney, NSW, Australia
- *Correspondence: Omar Z. Ameer,
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3
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Mariano VS, Boer PA, Gontijo JAR. Fetal Undernutrition Programming, Sympathetic Nerve Activity, and Arterial Hypertension Development. Front Physiol 2021; 12:704819. [PMID: 34867434 PMCID: PMC8635863 DOI: 10.3389/fphys.2021.704819] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Accepted: 10/14/2021] [Indexed: 12/11/2022] Open
Abstract
A wealth of evidence showed that low birth weight is associated with environmental disruption during gestation, triggering embryotic or fetal adaptations and increasing the susceptibility of progeny to non-communicable diseases, including metabolic and cardiovascular diseases, obesity, and arterial hypertension. In addition, dietary disturbance during pregnancy in animal models has highlighted mechanisms that involve the genesis of arterial hypertension, particularly severe maternal low-protein intake (LP). Functional studies demonstrated that maternal low-protein intake leads to the renal decrease of sodium excretion and the dysfunction of the renin-angiotensin-aldosterone system signaling of LP offspring. The antinatriuretic effect is accentuated by a reduced number of nephron units and glomerulosclerosis, which are critical in establishing arterial hypertension phenotype. Also, in this way, studies have shown that the overactivity of the central and peripheral sympathetic nervous system occurs due to reduced sensory (afferent) renal nerve activity. As a result of this reciprocal and abnormal renorenal reflex, there is an enhanced tubule sodium proximal sodium reabsorption, which, at least in part, contributes directly to arterial hypertension development in some of the programmed models. A recent study has observed that significant changes in adrenal medulla secretion could be involved in the pathophysiological process of increasing blood pressure. Thus, this review aims to compile studies that link the central and peripheral sympathetic system activity mechanisms on water and salt handle and blood pressure control in the maternal protein-restricted offspring. Besides, these pathophysiological mechanisms mainly may involve the modulation of neurokinins and catecholamines pathways.
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Affiliation(s)
- Vinícius Schiavinatto Mariano
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Nucleus of Medicine and Experimental Surgery, Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - Patrícia Aline Boer
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Nucleus of Medicine and Experimental Surgery, Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, São Paulo, Brazil
| | - José Antônio Rocha Gontijo
- Fetal Programming and Hydroelectrolyte Metabolism Laboratory, Nucleus of Medicine and Experimental Surgery, Department of Internal Medicine, Faculty of Medical Sciences, State University of Campinas, São Paulo, Brazil
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Boder P, Mary S, Mark PB, Leiper J, Dominiczak AF, Padmanabhan S, Rampoldi L, Delles C. Mechanistic interactions of uromodulin with the thick ascending limb: perspectives in physiology and hypertension. J Hypertens 2021; 39:1490-1504. [PMID: 34187999 PMCID: PMC7611110 DOI: 10.1097/hjh.0000000000002861] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertension is a significant risk factor for cardiovascular disease and mortality worldwide. The kidney is a major regulator of blood pressure and electrolyte homeostasis, with monogenic disorders indicating a link between abnormal ion transport and salt-sensitive hypertension. However, the association between salt and hypertension remains controversial. Thus, there is continued interest in deciphering the molecular mechanisms behind these processes. Uromodulin (UMOD) is the most abundant protein in the normal urine and is primarily synthesized by the thick ascending limb epithelial cells of the kidney. Genome-wide association studies have linked common UMOD variants with kidney function, susceptibility to chronic kidney disease and hypertension independent of renal excretory function. This review will discuss and provide predictions on the role of the UMOD protein in renal ion transport and hypertension based on current observational, biochemical, genetic, pharmacological and clinical evidence.
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Affiliation(s)
- Philipp Boder
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sheon Mary
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Patrick B. Mark
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - James Leiper
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Anna F. Dominiczak
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Sandosh Padmanabhan
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Luca Rampoldi
- Molecular Genetics of Renal Disorders Unit, Division of Genetics and Cell Biology, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Christian Delles
- BHF Glasgow Cardiovascular Research Centre, Institute of Cardiovascular and Medical Sciences, University of Glasgow, Glasgow, United Kingdom
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5
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Wang ZB, Jiang SL, Liu SB, Peng JB, Hu S, Wang X, Zhuo W, Liu T, Guo JW, Zhou HH, Yang ZQ, Mao XY, Liu ZQ. Metabolomics of Artichoke Bud Extract in Spontaneously Hypertensive Rats. ACS OMEGA 2021; 6:18610-18622. [PMID: 34337201 PMCID: PMC8319930 DOI: 10.1021/acsomega.1c01135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/05/2021] [Indexed: 05/10/2023]
Abstract
Hypertension adversely affects the quality of life in humans across modern society. Studies have attributed increased reactive oxygen species production to the pathophysiology of hypertension. So far, a specific drug to control the disease perfectly has not been developed. However, artichoke, an edible vegetable, plays an essential role in treating many diseases due to its potent antioxidant activities. The objective of this study is to evaluate the effect of artichoke bud extract (ABE) on heart tissue metabolomics of hypertensive rats. Spontaneously hypertensive rats and Wistar-Kyoto (WKY) rats were divided into six groups, then exposed to different doses comprising ABE, Enalapril Maleate, or 1% carboxylmethyl cellulose for 4 weeks. Their blood pressures were recorded at 0, 2, 3, and 4 weeks after the start of the test period. Thereafter, all rats were anesthetized, and blood was collected from their cardiac apexes. Then, we measured the levels for 15 kinds of serum biochemical parameters. An established orthogonal partial least square-discriminant analysis model completed the metabolomic analysis. Hypertensive rats in the ABE group exhibited well-controlled blood pressure, relative to those in the model group. Specifically, artichoke significantly lowered serum levels for total protein (TP), albumin (ALB), and uric acid (UA) in the hypertensive rats. This effect involved the action of eight metabolites, including guanine, 1-methylnicotinamide, p-aminobenzoic acid, NAD, NADH, uridine 5'-monophosphate, adenosine monophosphate, and methylmalonic acid. Collectively, these findings suggest that ABE may play a role in affecting oxidative stress and purine, nicotinate, and nicotinamide metabolism.
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Affiliation(s)
- Zhi-Bin Wang
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Shi-Long Jiang
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Shao-Bo Liu
- Department
of Pharmacy, Xiangya Hospital, Central South
University, Changsha 410008, P. R. China
| | - Jing-Bo Peng
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Shuo Hu
- Department
of Nuclear Medicine and Key Laboratory of Biological Nanotechnology
of National Health Commission, Xiangya Hospital, Central South University, Changsha 410008, P. R. China
| | - Xu Wang
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Wei Zhuo
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Tong Liu
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Ji-Wei Guo
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Hong-Hao Zhou
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Zhi-Quan Yang
- Department
of Neurosurgery, Xiangya Hospital, Central
South University, Changsha 410008, P. R. China
- . Phone: +86 731 89753845. Fax: +86 731 82354476
| | - Xiao-Yuan Mao
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
| | - Zhao-Qian Liu
- Department
of Clinical Pharmacology, Hunan Key Laboratory of Pharmacogenetics,
and National Clinical Research Center for Geriatric Disorders, Xiangya
Hospital, Central South University, Changsha 410008, P. R. China
- Institute
of Clinical Pharmacology, Engineering Research Center for Applied
Technology of Pharmacogenomics of Ministry of Education, Central South University, Changsha 410078, P. R. China
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6
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Ye C, Zheng F, Wang JX, Wang XL, Chen Q, Li YH, Kang YM, Zhu GQ. Dysregulation of the Excitatory Renal Reflex in the Sympathetic Activation of Spontaneously Hypertensive Rat. Front Physiol 2021; 12:673950. [PMID: 34149454 PMCID: PMC8209386 DOI: 10.3389/fphys.2021.673950] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 04/08/2021] [Indexed: 11/20/2022] Open
Abstract
Excessive sympathetic activation plays crucial roles in the pathogenesis of hypertension. Chemical stimulation of renal afferents increases the sympathetic activity and blood pressure in normal rats. This study investigated the excitatory renal reflex (ERR) in the development of hypertension in the spontaneously hypertensive rat (SHR). Experiments were performed in the Wistar-Kyoto rat (WKY) and SHR aged at 4, 12, and 24 weeks under anesthesia. Renal infusion of capsaicin was used to stimulate renal afferents, and thus, to induce ERR. The ERR was evaluated by the changes in the contralateral renal sympathetic nerve activity and mean arterial pressure. At the age of 4 weeks, the early stage with a slight or moderate hypertension, the ERR was more enhanced in SHR compared with WKY. The pressor response was greater than the sympathetic activation response in the SHR. At the age of 12 weeks, the development stage with severe hypertension, there was no significant difference in the ERR between the WKY and SHR. At the age of 24 weeks, the later stage of hypertension with long-term several hypertensions, the ERR was more attenuated in the SHR compared with the WKY. On the other hand, the pressor response to sympathetic activation due to the ERR was smaller at the age of 12 and 24 weeks than those at the age of 4 weeks. These results indicate that ERR is enhanced in the early stage of hypertension, and attenuated in the later stage of hypertension in the SHR. Abnormal ERR is involved in the sympathetic activation and the development of hypertension.
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Affiliation(s)
- Chao Ye
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Fen Zheng
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Jing-Xiao Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Xiao-Li Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China
| | - Qi Chen
- Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Yue-Hua Li
- Department of Pathophysiology, Nanjing Medical University, Nanjing, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an, China
| | - Guo-Qing Zhu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, Department of Physiology, Nanjing Medical University, Nanjing, China.,Department of Pathophysiology, Nanjing Medical University, Nanjing, China
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7
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Okamura M, Ueno T, Tanaka S, Murata Y, Kobayashi H, Miyamoto A, Abe M, Fukuda N. Increased expression of acyl-CoA oxidase 2 in the kidney with plasma phytanic acid and altered gut microbiota in spontaneously hypertensive rats. Hypertens Res 2021; 44:651-661. [PMID: 33504992 DOI: 10.1038/s41440-020-00611-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 12/12/2020] [Accepted: 12/13/2020] [Indexed: 01/31/2023]
Abstract
We performed a DNA microarray analysis of the renal medulla and cortex from spontaneously hypertensive rats (SHRs), stroke-prone SHRs (SHRSPs), and Wistar-Kyoto (WKY) rats to identify pivotal molecules in the kidney associated with the onset of hypertension and found increased expression of acyl-CoA oxidase 2 (Acox2) mRNA. Real-time polymerase chain reaction revealed that Acox2 mRNA expression in the renal medulla and cortex of SHRs and SHRSPs was increased in comparison to WKY rats. These findings indicate that increased renal ACOX2 (an enzyme that induces the β-oxidation of fatty acids) is associated with the onset of hypertension. Immunostaining of ACOX2 in the distal tubules from SHRs was stronger than that in the distal tubules from WKY rats. Western blot analysis showed increased expression of ACOX2 protein in renal medulla from SHRs. Regarding the overexpression of ACOX2, plasma levels of phytanic acid in SHRs were significantly higher than those in WKY rats. There were no differences in other short-chain fatty acids. Plasma phytanic acid was affected by the gut microbiota through the conversion from phytol by yeast in the intestinal tract. We compared the gut microbiota profile in three strains of 5-week-old rats by the terminal-restriction fragment length polymorphism method. The gut microbiota profile and ratio of Firmicutes/Bacteroides differed between SHRs and WKY rats. These findings suggest that the increased expression of ACOX2 in the kidney along with increases in plasma phytanic acid and the altered gut microbiota may be involved in the oxidation in the kidney and the pathogenesis of hypertension.
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Affiliation(s)
- Masahiro Okamura
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Takahiro Ueno
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Sho Tanaka
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Yusuke Murata
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Hiroki Kobayashi
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan
| | - Aoi Miyamoto
- Laboratory of Clinical Pharmacokinetics, School of Pharmacy, Nihon University, Chiba, Japan
| | - Masanori Abe
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan.
| | - Noboru Fukuda
- Division of Nephrology, Hypertension and Endocrinology, Department of Internal Medicine, Nihon University School of Medicine, Tokyo, Japan. .,Division of Cell Regeneration and Transplantation, Department of Functional Morphology, Nihon University School of Medicine, Tokyo, Japan.
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8
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Arterial hypertension and cystatin C during neonatal physiologic dehydration. J Hum Hypertens 2021; 36:554-560. [PMID: 33935283 DOI: 10.1038/s41371-021-00541-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 03/27/2021] [Accepted: 04/14/2021] [Indexed: 11/09/2022]
Abstract
A reduced nephron number may play a role in the pathogenesis of arterial hypertension (AH), and it is well recognized that individual nephron endowment is widely variable. However, nephrons count is technically impossible in vivo. Based on the observation that subjects with a reduced nephron mass exhibit an increase in renal functional biomarkers during acute dehydration, we hypothesized that cystatin C concentration during neonatal physiological dehydration could identify subjects with reduced nephron endowment. This is a prospective, observational, cohort study enrolling healthy, caucasian, term neonates born after an uneventful pregnancy. Two groups of newborns were compared: neonates born to fathers on antihypertensive treatment (HF) versus those born to proven normotensive fathers older than 40 years of age (NF). Enrolled newborns underwent cystatin C determination at the time of newborn screening. Forty newborns with HF and 80 with NF were enrolled. No differences in baseline characteristics were observed between the two groups except for the number of hypertensive grandparents higher among newborns to HF (47.8% vs. 21.1%; p: 0.001). Cystatin C was significantly higher in newborns with HF (1.62 ± 0.30 mg/L vs 1.41 ± 0.27 mg/L; p < 0.001). Linear regression analysis corrected for confounders confirmed that paternal hypertension was the only variable significantly associated with high cystatin C level during post-natal dehydration. Besides offering new insights on the pathogenesis of familial hypertension, our results support the specific role of nephron endowment and suggest the possibility of identifying subjects at risk for reduced nephron endowment as early as at birth.
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The antihypertensive effect and mechanisms of bioactive peptides from Ruditapes philippinarum fermented with Bacillus natto in spontaneously hypertensive rats. J Funct Foods 2021. [DOI: 10.1016/j.jff.2021.104411] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
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10
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Imig JD, Jankiewicz WK, Khan AH. Epoxy Fatty Acids: From Salt Regulation to Kidney and Cardiovascular Therapeutics: 2019 Lewis K. Dahl Memorial Lecture. Hypertension 2020; 76:3-15. [PMID: 32475311 DOI: 10.1161/hypertensionaha.120.13898] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Epoxyeicosatrienoic acids (EETs) are epoxy fatty acids that have biological actions that are essential for maintaining water and electrolyte homeostasis. An inability to increase EETs in response to a high-salt diet results in salt-sensitive hypertension. Vasodilation, inhibition of epithelial sodium channel, and inhibition of inflammation are the major EET actions that are beneficial to the heart, resistance arteries, and kidneys. Genetic and pharmacological means to elevate EETs demonstrated antihypertensive, anti-inflammatory, and organ protective actions. Therapeutic approaches to increase EETs were then developed for cardiovascular diseases. sEH (soluble epoxide hydrolase) inhibitors were developed and progressed to clinical trials for hypertension, diabetes mellitus, and other diseases. EET analogs were another therapeutic approach taken and these drugs are entering the early phases of clinical development. Even with the promise for these therapeutic approaches, there are still several challenges, unexplored areas, and opportunities for epoxy fatty acids.
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Affiliation(s)
- John D Imig
- From the Department of Pharmacology and Toxicology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee
| | - Wojciech K Jankiewicz
- From the Department of Pharmacology and Toxicology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee
| | - Abdul H Khan
- From the Department of Pharmacology and Toxicology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee
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Ye C, Qiu Y, Zhang F, Chen AD, Zhou H, Wang JJ, Chen Q, Li YH, Kang YM, Zhu GQ. Chemical Stimulation of Renal Tissue Induces Sympathetic Activation and a Pressor Response via the Paraventricular Nucleus in Rats. Neurosci Bull 2019; 36:143-152. [PMID: 31392556 DOI: 10.1007/s12264-019-00417-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Accepted: 06/03/2019] [Indexed: 12/12/2022] Open
Abstract
Sympathetic activation and the kidney play critical roles in hypertension and chronic heart failure. The role of the kidney in sympathetic activation is still not well known. In this study, we revealed an excitatory renal reflex (ERR) in rats induced by chemical stimulation of the kidney that regulated sympathetic activity and blood pressure. The ERR was induced by renal infusion of capsaicin, and evaluated by the changes in renal sympathetic outflow, blood pressure, and heart rate. Renal infusion of capsaicin dose-dependently increased the contralateral renal sympathetic nerve activity, mean arterial pressure, and heart rate. Capsaicin in the cortico-medullary border had greater effects than in the cortex or medulla. Intravenous infusion of capsaicin had no significant effects. The effects of renal infusion of capsaicin were abolished by ipsilateral renal denervation, but were not affected by bilateral sinoaortic denervation. Renal infusion of capsaicin increased the ipsilateral renal afferent activity. The ERR was also induced by renal infusion of bradykinin, adenosine, and angiotensin II, but not by ATP. Renal infusion of capsaicin increased c-Fos expression in the paraventricular nucleus (PVN) of hypothalamus. Lesion of neurons in the PVN with kainic acid abolished the capsaicin-induced ERR. These findings indicate that chemical stimulation of kidney causes an excitatory reflex, leading to sympathetic activation, pressor response, and accelerated heart rate. The PVN is an important central nucleus in the pathway of the ERR.
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Affiliation(s)
- Chao Ye
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Yun Qiu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Feng Zhang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Ai-Dong Chen
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Hong Zhou
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Jue-Jin Wang
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Qi Chen
- Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Yue-Hua Li
- Department of Physiology, Nanjing Medical University, Nanjing, 211166, China
| | - Yu-Ming Kang
- Department of Physiology and Pathophysiology, Cardiovascular Research Center, Xi'an Jiaotong University School of Medicine, Xi'an, 710061, China
| | - Guo-Qing Zhu
- Key Laboratory of Targeted Intervention of Cardiovascular Disease, Collaborative Innovation Center of Translational Medicine for Cardiovascular Disease, and Department of Physiology, Nanjing Medical University, Nanjing, 211166, China. .,Department of Physiology, Nanjing Medical University, Nanjing, 211166, China.
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Petit G, Jury V, Lamballerie M, Duranton F, Pottier L, Martin J. Salt Intake from Processed Meat Products: Benefits, Risks and Evolving Practices. Compr Rev Food Sci Food Saf 2019; 18:1453-1473. [DOI: 10.1111/1541-4337.12478] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Revised: 06/14/2019] [Accepted: 06/19/2019] [Indexed: 01/11/2023]
Affiliation(s)
- Gaëlle Petit
- ONIRIS ‐ Ecole Nationale VétérinaireAgroalimentaire et de l'alimentation Nantes‐Atlantique Rue de la Géraudière, BP 62241 44322 Nantes Cedex France
- GEPEA ‐ Laboratoire de Génie des Procédés ‐ Environnement – Agroalimentaire ‐ MAPS2 ‐ Matrices Aliments Procédés Propriétés Structure – Sensoriel 44322 Nantes Cedex France
| | - Vanessa Jury
- ONIRIS ‐ Ecole Nationale VétérinaireAgroalimentaire et de l'alimentation Nantes‐Atlantique Rue de la Géraudière, BP 62241 44322 Nantes Cedex France
- GEPEA ‐ Laboratoire de Génie des Procédés ‐ Environnement – Agroalimentaire ‐ MAPS2 ‐ Matrices Aliments Procédés Propriétés Structure – Sensoriel 44322 Nantes Cedex France
| | - Marie Lamballerie
- ONIRIS ‐ Ecole Nationale VétérinaireAgroalimentaire et de l'alimentation Nantes‐Atlantique Rue de la Géraudière, BP 62241 44322 Nantes Cedex France
- GEPEA ‐ Laboratoire de Génie des Procédés ‐ Environnement – Agroalimentaire ‐ MAPS2 ‐ Matrices Aliments Procédés Propriétés Structure – Sensoriel 44322 Nantes Cedex France
| | | | - Laurence Pottier
- ONIRIS ‐ Ecole Nationale VétérinaireAgroalimentaire et de l'alimentation Nantes‐Atlantique Rue de la Géraudière, BP 62241 44322 Nantes Cedex France
- GEPEA ‐ Laboratoire de Génie des Procédés ‐ Environnement – Agroalimentaire ‐ MAPS2 ‐ Matrices Aliments Procédés Propriétés Structure – Sensoriel 44322 Nantes Cedex France
| | - Jean‐Luc Martin
- Ifip‐Institut du PorcPôle viandes et charcuteries 7 Avenue du Général de Gaulle 94700 Maisons‐Alfort France
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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Hydrogen Sulfide Inhibits High-Salt Diet-Induced Renal Oxidative Stress and Kidney Injury in Dahl Rats. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2015; 2016:2807490. [PMID: 26823949 PMCID: PMC4707377 DOI: 10.1155/2016/2807490] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/22/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 12/18/2022]
Abstract
Background. The study was designed to investigate if H2S could inhibit high-salt diet-induced renal excessive oxidative stress and kidney injury in Dahl rats. Methods. Male salt-sensitive Dahl and SD rats were used. Blood pressure (BP), serum creatinine, urea, creatinine clearance rate, and 24-hour urine protein were measured. Renal ultra- and microstructures were observed. Collagen-I and -III contents the oxidants and antioxidants levels in renal tissue were detected. Keap1/Nrf2 association and Keap1 s-sulfhydration were detected. Results. After 8 weeks of high-salt diet, BP was significantly increased, renal function and structure were impaired, and collagen deposition was abundant in renal tissues with increased renal MPO activity, H2O2, MDA, GSSG, and •OH contents, reduced renal T-AOC and GSH contents, CAT, GSH-PX and SOD activity, and SOD expressions in Dahl rats. Furthermore, endogenous H2S in renal tissues was decreased in Dahl rats. H2S donor, however, decreased BP, improved renal function and structure, and inhibited collagen excessive deposition in kidney, in association with increased antioxidative activity and reduced oxidative stress in renal tissues. H2S activated Nrf2 by inducing Keap1 s-sulfhydration and subsequent Keap1/Nrf2 disassociation. Conclusions. H2S protected against high-salt diet-induced renal injury associated with enhanced antioxidant capacity and inhibited renal oxidative stress.
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15
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Ahmeda AF, Alzoghaibi M. Factors regulating the renal circulation in spontaneously hypertensive rats. Saudi J Biol Sci 2015; 23:441-51. [PMID: 27298576 PMCID: PMC4890190 DOI: 10.1016/j.sjbs.2015.06.016] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 06/14/2015] [Accepted: 06/19/2015] [Indexed: 01/17/2023] Open
Abstract
Hypertension is one of the leading causes of health morbidity and mortality which are linked to many life threatening diseases such as stroke heart problems and renal dysfunction. The integrity of renal microcirculation is crucial to maintaining the clearance and the excretory function in the normotensive and hypertensive conditions. Furthermore, any alteration in the renal function is involved in the pathophysiology of hypertension. The aim of this review is to provide a brief discussion of some factors that regulate renal haemodynamics in spontaneously hypertensive rats, an animal model of hypertension, and how these factors are linked to the disease.
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Affiliation(s)
- Ahmad F Ahmeda
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
| | - Mohammed Alzoghaibi
- Department of Physiology, College of Medicine, King Saud University, Riyadh, Saudi Arabia
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16
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Majid DSA, Prieto MC, Navar LG. Salt-Sensitive Hypertension: Perspectives on Intrarenal Mechanisms. Curr Hypertens Rev 2015; 11:38-48. [PMID: 26028244 DOI: 10.2174/1573402111666150530203858] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 04/22/2015] [Accepted: 04/24/2015] [Indexed: 12/12/2022]
Abstract
Salt sensitive hypertension is characterized by increases in blood pressure in response to increases in dietary salt intake and is associated with an enhanced risk of cardiovascular and renal morbidity. Although researchers have sought for decades to understand how salt sensitivity develops in humans, the mechanisms responsible for the increases in blood pressure in response to high salt intake are complex and only partially understood. Until now, scientists have been unable to explain why some individuals are salt sensitive and others are salt resistant. Although a central role for the kidneys in the development of salt sensitivity and hypertension has been generally accepted, it is also recognized that hypertension is of multifactorial origin and a variety of factors can induce, or prevent, blood pressure responsiveness to the manipulation of salt intake. Excess salt intake in susceptible persons may also induce inappropriate central and sympathetic nervous system responses and increase the production of intrarenal angiotensin II, catecholamines and other factors such as oxidative stress and inflammatory cytokines. One key factor is the concomitant inappropriate or paradoxical activation of the intrarenal renin-angiotensin system, by high salt intake. This is reflected by the increases in urinary angiotensinogen during high salt intake in salt sensitive models. A complex interaction between neuroendocrine factors and the kidney may underlie the propensity for some individuals to retain salt and develop salt-dependent hypertension. In this review, we focus mainly on the renal contributions that provide the mechanistic links between chronic salt intake and the development of hypertension.
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Affiliation(s)
- Dewan S A Majid
- Department of Physiology, SL39, Tulane University School of Medicine, 1430 Tulane Avenue, New Orleans, LA 70112, USA.
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17
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Cytochrome P450 1B1 contributes to increased blood pressure and cardiovascular and renal dysfunction in spontaneously hypertensive rats. Cardiovasc Drugs Ther 2014; 28:145-61. [PMID: 24477449 DOI: 10.1007/s10557-014-6510-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
PURPOSE We investigated the contribution of cytochrome P450 (CYP) 1B1 to hypertension and its pathogenesis by examining the effect of its selective inhibitor, 2,4,3',5'-tetramethoxystilbene (TMS), in spontaneously hypertensive rats (SHR). METHODS Blood pressure (BP) was measured bi-weekly. Starting at 8 weeks, TMS (600 μg/kg, i.p.) or its vehicle was injected daily. At 14 weeks, samples were collected for measurement. RESULTS TMS reversed increased BP in SHR (207 ± 7 vs. 129 ± 2 mmHg) without altering BP in Wistar-Kyoto rats. Increased CYP1B1 activity in SHR was inhibited by TMS (RLU: aorta, 5.4 ± 0.7 vs. 3.7 ± 0.7; heart, 6.0 ± 0.8 vs. 3.4 ± 0.4; kidney, 411 ± 45 vs. 246 ± 10). Increased vascular reactivity, cardiovascular hypertrophy, endothelial and renal dysfunction, cardiac and renal fibrosis in SHR were minimized by TMS. Increased production of reactive oxygen species and NADPH oxidase activity in SHR, were diminished by TMS. In SHR, TMS reduced increased plasma levels of nitrite/nitrate (46.4 ± 5.0 vs. 28.1 ± 4.1 μM), hydrogen-peroxide (36.0 ± 3.7 vs. 14.1 ± 3.8 μM), and thiobarbituric acid reactive substances (6.9 ± 1.0 vs. 3.4 ± 1.5 μM). Increased plasma levels of pro-inflammatory cytokines and catecholamines, and cardiac activity of extracellular signal-regulated kinase, p38 mitogen-activated protein kinase, c-Src tyrosine kinase, and protein kinase B in SHR were also inhibited by TMS. CONCLUSIONS These data suggests that increased oxidative stress generated by CYP1B1 contributes to hypertension, increased cytokine production and sympathetic activity, and associated pathophysiological changes in SHR. CYP1B1 could be a novel target for developing drugs to treat hypertension and its pathogenesis.
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18
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Ivy JR, Bailey MA. Pressure natriuresis and the renal control of arterial blood pressure. J Physiol 2014; 592:3955-67. [PMID: 25107929 DOI: 10.1113/jphysiol.2014.271676] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The regulation of extracellular fluid volume by renal sodium excretion lies at the centre of blood pressure homeostasis. Renal perfusion pressure can directly regulate sodium reabsorption in the proximal tubule. This acute pressure natriuresis response is a uniquely powerful means of stabilizing long-term blood pressure around a set point. By logical extension, deviation from the set point can only be sustained if the pressure natriuresis mechanism is impaired, suggesting that hypertension is caused or sustained by a defect in the relationship between renal perfusion pressure and sodium excretion. Here we describe the role of pressure natriuresis in blood pressure control and outline the cascade of biophysical and paracrine events in the renal medulla that integrate the vascular and tubular response to altered perfusion pressure. Pressure natriuresis is impaired in hypertension and mechanistic insight into dysfunction comes from genetic analysis of blood pressure disorders. Transplantation studies in rats show that blood pressure is determined by the genotype of the kidney and Mendelian hypertension indicates that the distal nephron influences the overall natriuretic efficiency. These approaches and the outcomes of genome-wide-association studies broaden our view of blood pressure control, suggesting that renal sympathetic nerve activity and local inflammation can impair pressure natriuresis to cause hypertension. Understanding how these systems interact is necessary to tackle the global burden of hypertension.
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Affiliation(s)
- Jessica R Ivy
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
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19
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Tomita K. [110th Scientific Meeting of the Japanese Society of Internal Medicine: Invited lecture: 2. Strategy for the treatment of hypertension in chronic kidney disease, focusing on Na regulation]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 2013; 102:2169-2181. [PMID: 24228398 DOI: 10.2169/naika.102.2169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Affiliation(s)
- Kimio Tomita
- Department of Nephrology, Graduate School of Faculty of Life Science, Kumamoto University, Japan
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20
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Girardi ACC, Di Sole F. Deciphering the mechanisms of the Na+/H+ exchanger-3 regulation in organ dysfunction. Am J Physiol Cell Physiol 2012; 302:C1569-87. [DOI: 10.1152/ajpcell.00017.2012] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The Na+/H+ exchanger-3 (NHE3) belongs to the mammalian NHE protein family and catalyzes the electro-neutral exchange of extracellular sodium for intracellular proton across cellular membranes. Its transport function is of essential importance for the maintenance of the body's salt and water homeostasis as well as acid-base balance. Indeed, NHE3 activity is finely regulated by a variety of stimuli, both acutely and chronically, and its transport function is fundamental for a multiplicity of severe and world-wide infection-pathological conditions. This review aims to provide a concise overview of NHE3 physiology and discusses the role of NHE3 in clinical conditions of prominent importance, specifically in hypertension, diabetic nephropathy, heart failure, acute kidney injury, and diarrhea. Study of NHE3 function in models of these diseases has contributed to the deciphering of mechanisms that control the delicate ion balance disrupted in these disorders. The majority of the findings indicate that NHE3 transport function is activated before the onset of hypertension and inhibited thereafter; NHE3 transport function is also upregulated in diabetic nephropathy and heart failure, while it is reported to be downregulated in acute kidney injury and in diarrhea. The molecular mechanisms activated during these pathological conditions to regulate NHE3 transport function are examined with the aim of linking NHE3 dysfunction to the analyzed clinical disorders.
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Affiliation(s)
| | - Francesca Di Sole
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
- Center of Mineral Metabolism and Clinical Research, University of Texas Southwestern Medical Center, Dallas, Texas
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21
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Ritz E, Amann K, Koleganova N, Benz K. Prenatal programming-effects on blood pressure and renal function. Nat Rev Nephrol 2011; 7:137-44. [PMID: 21283139 DOI: 10.1038/nrneph.2011.1] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Impaired intrauterine nephrogenesis-most clearly illustrated by low nephron number-is frequently associated with low birthweight and has been recognized as a powerful risk factor for renal disease; it increases the risks of low glomerular filtration rate, of more rapid progression of primary kidney disease, and of increased incidence of chronic kidney disease or end-stage renal disease. Another important consequence of impaired nephrogenesis is hypertension, which further amplifies the risk of onset and progression of kidney disease. Hypertension is associated with low nephron numbers in white individuals, but the association is not universal and is not seen in individuals of African origin. The derangement of intrauterine kidney development is an example of a more general principle that illustrates the paradigm of plasticity during development-that is, that transcription of the genetic code is modified by epigenetic factors (as has increasingly been documented). This Review outlines the concept of prenatal programming and, in particular, describes its role in kidney disease and hypertension.
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Affiliation(s)
- Eberhard Ritz
- Division of Nephrology, Department of Internal Medicine, University of Heidelberg, Heidelberg 69100, Germany.
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22
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23
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Abstract
The vascular endothelium starts to age at the first heartbeat. There is no longer a need to demonstrate that an increased resting heart rate--above 70 b.p.m.--is associated with the onset of cardiovascular events and reduces lifespan in humans. Each cardiac cycle imposes a mechanical constraint on the arteries, and we would like to propose that this mechanical stress damages the vascular endothelium, its dysfunction being the prerequisite for atherogenesis. Consequently, reducing heart rate could protect the endothelium and slow the onset of atherosclerosis. The potential mechanisms by which reducing heart rate could be beneficial to the endothelium are likely a combination of a reduction in mechanical stress and tissue fatigue and a prolongation of the period of steady laminar flow, and thus sustained shear stress, between each systole. With age, irreparable damage accumulates in endothelial cells and leads to senescence, which is characterized by a pro-atherogenic phenotype. In the body, the highest mechanical stress occurs in the coronary vessels, where blood only flows during diastole and even reverses during systole; thus, coronary arteries are the prime site of atherosclerosis. All classical risk factors for cardiovascular diseases add up, to accelerate atherogenesis, but hypertension, which further raises mechanical stress, is likely the most damaging. By inducing flow through the arteries, the heart rate determines shear stress and its stability: mechanical stress and the associated damage induced by each systole are efficiently counteracted by the repair capacities of a healthy endothelium. The maintenance of a physiological, low heart rate may be key to prolonging the endothelial healthy lifespan and thus, vascular health.
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Affiliation(s)
- Eric Thorin
- Faculty of Medicine, Department of Surgery, Montreal Heart Institute, Research Centre, Université de Montréal, 5000 rue Bélanger, Montréal, QC, Canada.
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Joyner MJ, Charkoudian N, Wallin BG. A sympathetic view of the sympathetic nervous system and human blood pressure regulation. Exp Physiol 2008; 93:715-24. [PMID: 18326553 DOI: 10.1113/expphysiol.2007.039545] [Citation(s) in RCA: 102] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
New ideas about the relative importance of the autonomic nervous system (and especially its sympathetic arm) in long-term blood pressure regulation are emerging. It is well known that mean arterial blood pressure is normally regulated in a fairly narrow range at rest and that blood pressure is also able to rise and fall 'appropriately' to meet the demands of various forms of mental, emotional and physical stress. By contrast, blood pressure varies widely when the autonomic nervous system is absent or when key mechanisms that govern it are destroyed. However, 24 h mean arterial pressure is still surprisingly normal under these conditions. Thus, the dominant idea has been that the kidney is the main long-term regulator of blood pressure and the autonomic nervous system is important in short-term regulation. However, this 'renocentric' scheme can be challenged by observations in humans showing that there is a high degree of individual variability in elements of the autonomic nervous system. Along these lines, the level of sympathetic outflow, the adrenergic responsiveness of blood vessels and individual haemodynamic patterns appear to exist in a complex, but appropriate, balance in normotension. Furthermore, evidence from animals and humans has now clearly shown that the sympathetic nervous system can play an important role in longer term blood pressure regulation in both normotension and hypertension. Finally, humans with high baseline sympathetic traffic might be at increased risk for hypertension if the 'balance' among factors deteriorates or is lost. In this context, the goal of this review is to encourage a comprehensive rethinking of the complexities related to long-term blood pressure regulation in humans and promote finer appreciation of physiological relationships among the autonomic nervous system, vascular function, ageing, metabolism and blood pressure.
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Affiliation(s)
- Michael J Joyner
- Departments of Anesthesiology and Physiology & Biomedical Engineering, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
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Abstract
This article reviews studies by the author on central mechanisms of hypertension. Spontaneously hypertensive rats (SHR) have been developed as a rat model of genetic hypertension, and central acetylcholine has been implicated in hypertension in SHR. The rostral ventrolateral medulla (RVL), a major source of efferent sympathetic activity, has cholinergic pressor systems. The release of acetylcholine is enhanced in the RVL of SHR, leading to hypertension. The alteration of the RVL cholinergic system in SHR results from enhanced angiotensin systems in the anterior hypothalamic area (AHA). Angiotensin II-sensitive neurons are present in the AHA and they are tonically activated by endogenous angiotensins. The basal activity of AHA angiotensin II-sensitive neurons is enhanced in SHR, mainly due to enhanced sensitivity of AHA neurons to angiotensin II. The AHA angiotensin system is also responsible for hypertension induced by emotional stress and central Na(+) increases. These findings suggest that the AHA angiotensin system may play a critical role in the development of hypertension.
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Affiliation(s)
- Takao Kubo
- Showa Pharmaceutical University, Machida City, Japan.
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26
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Abstract
In this review, we outline the application and contribution of transgenic technology to establishing the genetic basis of blood pressure regulation and its dysfunction. Apart from a small number of examples where high blood pressure is the result of single gene mutation, essential hypertension is the sum of interactions between multiple environmental and genetic factors. Candidate genes can be identified by a variety of means including linkage analysis, quantitative trait locus analysis, association studies, and genome-wide scans. To test the validity of candidate genes, it is valuable to model hypertension in laboratory animals. Animal models generated through selective breeding strategies are often complex, and the underlying mechanism of hypertension is not clear. A complementary strategy has been the use of transgenic technology. Here one gene can be selectively, tissue specifically, or developmentally overexpressed, knocked down, or knocked out. Although resulting phenotypes may still be complicated, the underlying genetic perturbation is a starting point for identifying interactions that lead to hypertension. We recognize that the development and maintenance of hypertension may involve many systems including the vascular, cardiac, and central nervous systems. However, given the central role of the kidney in normal and abnormal blood pressure regulation, we intend to limit our review to models with a broadly renal perspective.
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Affiliation(s)
- Linda J Mullins
- Molecular Physiology Laboratory, Centre for Cardiovascular Science, Queens Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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Meneton P, Jeunemaitre X, de Wardener HE, MacGregor GA. Links between dietary salt intake, renal salt handling, blood pressure, and cardiovascular diseases. Physiol Rev 2005; 85:679-715. [PMID: 15788708 DOI: 10.1152/physrev.00056.2003] [Citation(s) in RCA: 447] [Impact Index Per Article: 23.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Epidemiological, migration, intervention, and genetic studies in humans and animals provide very strong evidence of a causal link between high salt intake and high blood pressure. The mechanisms by which dietary salt increases arterial pressure are not fully understood, but they seem related to the inability of the kidneys to excrete large amounts of salt. From an evolutionary viewpoint, the human species is adapted to ingest and excrete <1 g of salt per day, at least 10 times less than the average values currently observed in industrialized and urbanized countries. Independent of the rise in blood pressure, dietary salt also increases cardiac left ventricular mass, arterial thickness and stiffness, the incidence of strokes, and the severity of cardiac failure. Thus chronic exposure to a high-salt diet appears to be a major factor involved in the frequent occurrence of hypertension and cardiovascular diseases in human populations.
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Affiliation(s)
- Pierre Meneton
- Institut National de la Santé et de la Recherche Médicale U367, Département de Santé Publique et d'Informatique Médicale, Faculté de Médecine Broussais Hôtel Dieu, Paris, France.
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Abstract
There is increasing evidence that primary hypertension, coronary heart disease, and other aspects of the so-called metabolic syndrome that develop in adulthood are primed in fetal life or early postnatally. The identification of this phenomenon, also known as prenatal or fetal programming, and the detailed characterization of the underlying pathomechanisms will greatly influence the understanding of these diseases. The present paper reviews recent experimental and clinical evidence that low nephron number, found in patients with renal dysplasia and low birth weight, is a risk factor for cardiovascular disease in later life. Therefore, it is important to identify children at risk as early as possible in order to treat them early and to prevent the development of end-organ damage. This could be an important goal for pediatrics in the near future.
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Affiliation(s)
- Kerstin Amann
- Department of Pathology, University of Erlangen-Nürnberg, Krankenhausstrasse 8-10, 91054 Erlangen, Germany.
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29
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Grisk O, Rose HJ, Lorenz G, Rettig R. Sympathetic-renal interaction in chronic arterial pressure control. Am J Physiol Regul Integr Comp Physiol 2002; 283:R441-50. [PMID: 12121857 DOI: 10.1152/ajpregu.00669.2001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The effects of neonatal sympathectomy of donors or recipients on posttransplantation arterial pressure were investigated in spontaneously hypertensive rats (SHR) by renal transplantation experiments. Conscious mean arterial pressure (MAP) and renal vascular resistance were 136 +/- 1 mmHg and 15.5 +/- 1.2 mmHg x ml(-1) x min x g in sympathectomized SHR (n = 8) vs. 158 +/- 4 mmHg (P < 0.001) and 20.8 +/- 1.1 mmHg x ml(-1) x min x g (P < 0.05) in controls (n = 10). Seven weeks after transplantation of a kidney from neonatally sympathectomized SHR donors, MAP in SHR recipients (n = 10) was 20 mmHg lower than in controls transplanted with a kidney from hydralazine-treated SHR (n = 10) (P < 0.05) associated with reduced sodium sensitivity of MAP. Neonatal sympathectomy also lowered MAP in F1-hybrids (F1H; SHR x Wistar-Kyoto rats). Within 6 wk after transplantation, renal grafts from untreated SHR increased MAP by 20 mmHg in sympathectomized F1H (n = 10) and by 35 mmHg in sham-treated F1H (n = 8) (P < 0.05). Neonatal sympathectomy induces chronic changes in SHR kidney function leading to a MAP reduction even when extrarenal sympathetic tone is restored. Generalized reduction in sympathetic tone resets the kidney-fluid system to reduced MAP and blunts the extent of arterial pressure rise induced by an SHR kidney graft.
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Affiliation(s)
- Olaf Grisk
- Department of Physiology, Ernst-Moritz-Arndt-University, D-17487 Greifswald, Germany.
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30
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Grisk O, Klöting I, Exner J, Spiess S, Schmidt R, Junghans D, Lorenz G, Rettig R. Long-term arterial pressure in spontaneously hypertensive rats is set by the kidney. J Hypertens 2002; 20:131-8. [PMID: 11791036 DOI: 10.1097/00004872-200201000-00019] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES We investigated whether arterial pressure in spontaneously hypertensive rats (SHR) can be normalized by a kidney graft from normotensive histocompatible donors. In addition, the effect of differential genetic predisposition to hypertension of recipients of an SHR kidney on the development of post-transplantation hypertension was studied. METHODS SHR were transplanted with a kidney from congenic rats (BB.1K) homozygous for a 2 cM segment of SHR chromosome 20, including the major histocompatibility complex class Ia and class II genes. BB.1K and F1 hybrids (F1H, SHR x Wistar-Kyoto rats) were transplanted with an SHR kidney and the development of renal post-transplantation hypertension was monitored. RESULTS Thirty days after renal transplantation, mean arterial pressure (MAP) was 116 +/- 4 mmHg in SHR with a BB.1K kidney (n = 8) versus 168 +/- 2 mmHg in sham-operated SHR (n = 10); P < 0.001. Cumulative renal sodium balance (mmol/100 g body weight) over 21 days after bilateral nephrectomy was 6.8 +/- 0.6 in SHR with a BB.1K kidney versus 10.8 +/- 1.6 in sham-operated SHR (P < 0.05). Within 60 days of transplantation, MAP increased in BB.1K and in F1H transplanted with an SHR kidney (n = 7 per group) by 38 +/- 5 mmHg and 43 +/- 8 mmHg, respectively. CONCLUSIONS In SHR, arterial pressure can be normalized by a kidney graft from normotensive donors. The genetic predisposition of the recipients to hypertension does not modify the rate and the extent of the arterial pressure rise induced by an SHR kidney graft.
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Affiliation(s)
- Olaf Grisk
- Department of Physiology, University of Greifswald, Greifswalder Strasse 11c, D-17495 Karlsburg, Germany.
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31
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Abstract
Most forms of hypertension are associated with a wide variety of functional changes in the hypothalamus. Alterations in the following substances are discussed: catecholamines, acetylcholine, angiotensin II, natriuretic peptides, vasopressin, nitric oxide, serotonin, GABA, ouabain, neuropeptide Y, opioids, bradykinin, thyrotropin-releasing factor, vasoactive intestinal polypeptide, tachykinins, histamine, and corticotropin-releasing factor. Functional changes in these substances occur throughout the hypothalamus but are particularly prominent rostrally; most lead to an increase in sympathetic nervous activity which is responsible for the rise in arterial pressure. A few appear to be depressor compensatory changes. The majority of the hypothalamic changes begin as the pressure rises and are particularly prominent in the young rat; subsequently they tend to fluctuate and overall to diminish with age. It is proposed that, with the possible exception of the Dahl salt-sensitive rat, the hypothalamic changes associated with hypertension are caused by renal and intrathoracic cardiopulmonary afferent stimulation. Renal afferent stimulation occurs as a result of renal ischemia and trauma as in the reduced renal mass rat. It is suggested that afferents from the chest arise, at least in part, from the observed increase in left auricular pressure which, it is submitted, is due to the associated documented impaired ability to excrete sodium. It is proposed, therefore, that the hypothalamic changes in hypertension are a link in an integrated compensatory natriuretic response to the kidney's impaired ability to excrete sodium.
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Affiliation(s)
- H E de Wardener
- Department of Clinical Chemistry, Imperial College School of Medicine, Charing Cross Campus, London, United Kingdom.
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Grisk O, Frey BA, Uber A, Rettig R. Sympathetic activity in early renal posttransplantation hypertension in rats. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1737-44. [PMID: 11049857 DOI: 10.1152/ajpregu.2000.279.5.r1737] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The contribution of elevated sympathetic activity to the development of renal posttransplantation hypertension was investigated. F1 hybrids (F1H) from spontaneously hypertensive rats (SHR) and Wistar-Kyoto rats (WKY) were transplanted with either an SHR or an F1H kidney and bilaterally nephrectomized. Three weeks after transplantation, sympathetic activity was assessed by measuring adrenal tyrosine hydroxylase (TH) mRNA content and recording splanchnic nerve activity (SNA) in conscious animals. To investigate the dependence of arterial pressure on sympathetic activity, animals were treated with the alpha(2)-adrenoceptor agonist guanabenz intracerebroventricularly. Mean arterial pressure (MAP) was 143 +/- 4 mmHg in recipients of an SHR kidney (n = 15) versus 110 +/- 3 mmHg in recipients of an F1H kidney (n = 10; P < 0.001). Adrenal TH mRNA content was 1.93 +/- 0.15 fmol/microg total RNA in recipients of an SHR kidney versus 1.96 +/- 0.17 fmol/microg total RNA in recipients of an F1H kidney (not significant). SNA did not differ significantly between recipients of an SHR kidney (n = 8) and recipients of an F1H kidney (n = 7) in terms of frequency and amplitude of synchronized nerve discharges. In response to cumulative intracerebroventricular administration of 10 and 20 microg guanabenz, SNA fell to 51 +/- 5% of control in recipients of an SHR kidney versus 44 +/- 6% of control in recipients of an F1H kidney (not significant) accompanied by a slight fall in MAP in either group. The results suggest that elevated sympathetic activity is not a major contributor to the development of renal posttransplantation hypertension.
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Affiliation(s)
- O Grisk
- Department of Physiology, Ernst-Moritz-Arndt-University, D-17487 Greifswald, Germany.
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33
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Frey BA, Grisk O, Bandelow N, Wussow S, Bie P, Rettig R. Sodium homeostasis in transplanted rats with a spontaneously hypertensive rat kidney. Am J Physiol Regul Integr Comp Physiol 2000; 279:R1099-104. [PMID: 10956271 DOI: 10.1152/ajpregu.2000.279.3.r1099] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Recipients of a kidney from spontaneously hypertensive rats (SHR) but not from normotensive Wistar-Kyoto rats (WKY) develop posttransplantation hypertension. To investigate whether renal sodium retention precedes the development of posttransplantation hypertension in recipients of an SHR kidney on a standard sodium diet (0.6% NaCl), we transplanted SHR and WKY kidneys to SHR x WKY F1 hybrids, measured daily sodium balances during the first 12 days after removal of both native kidneys, and recorded mean arterial pressure (MAP) after 8 wk. Recipients of an SHR kidney (n = 12) retained more sodium than recipients of a WKY kidney (n = 12) (7.3 +/- 10 vs. 4.0 +/- 0.7 mmol, P < 0.05). MAP was 144 +/- 6 mmHg in recipients of an SHR kidney and 106 +/- 5 mmHg in recipients of a WKY kidney (P < 0.01). Modest sodium restriction (0.2% NaCl) in a further group of recipients of an SHR kidney (n = 10) did not prevent posttransplantation hypertension (MAP, 142 +/- 4 mmHg). Urinary endothelin and urodilatin excretion rates were similar in recipients of an SHR and a WKY kidney. Transient excess sodium retention after renal transplantation may contribute to posttransplantation hypertension in recipients of an SHR kidney.
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Affiliation(s)
- B A Frey
- Department of Physiology, Ernst Moritz Arndt University Greifswald, D-17495 Karlsburg, Germany
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34
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Martens JR, Reaves PY, Lu D, Katovich MJ, Berecek KH, Bishop SP, Raizada MK, Gelband CH. Prevention of renovascular and cardiac pathophysiological changes in hypertension by angiotensin II type 1 receptor antisense gene therapy. Proc Natl Acad Sci U S A 1998; 95:2664-9. [PMID: 9482944 PMCID: PMC19454 DOI: 10.1073/pnas.95.5.2664] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/1997] [Accepted: 12/10/1997] [Indexed: 02/06/2023] Open
Abstract
Hypertension produces pathophysiological changes that are often responsible for the mortality associated with the disease. However, it is unclear whether normalizing blood pressure (BP) with conventional therapy is effective in reversing the pathophysiological damage. The duration and initiation of treatment, site of administration, and agent used all appear to influence the reversal of the pathophysiological alterations associated with hypertension. We have previously established that retrovirally mediated delivery of angiotensin II type 1 receptor antisense (AT1R-AS) attenuates the development of high BP in the spontaneously hypertensive (SH) rat model of human essential hypertension. Our objective was to determine whether this attenuation of high BP is associated with prevention of other pathophysiological changes induced by the hypertensive state. Intracardiac delivery of AT1R-AS in neonates prevented the development of hypertension in SH rats for at least 120 days. Contractile experiments demonstrated an impaired endothelium-dependent vascular relaxation (acetylcholine) and an enhanced contractile response to vasoactive agents (phenylephrine and KCl) in the SH rat renal vasculature. In addition, the voltage-dependent K+ current density, which is believed to contribute to smooth muscle resting membrane potential and basal tone, was decreased in renal resistance artery cells of the SH rat. AT1R-AS treatment prevented each of these renal vascular alterations. Finally, AT1R-AS delivery prevented the pathological alterations observed in the SH rat myocardium, including left ventricular hypertrophy, multifocal fibrosis, and perivascular fibrosis. These observations demonstrate that viral-mediated delivery of AT1R-AS attenuates the development of hypertension on a long term basis, and this is associated with prevention of pathophysiological changes in SH rats.
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MESH Headings
- Acetylcholine/pharmacology
- Animals
- Animals, Newborn
- Blood Pressure
- Cardiomegaly/prevention & control
- Coronary Vessels/pathology
- Coronary Vessels/physiology
- Coronary Vessels/physiopathology
- DNA, Antisense
- Fibrosis
- Genetic Therapy
- Genetic Vectors
- Heart/physiology
- Heart/physiopathology
- Heart Ventricles
- Humans
- Hypertension/genetics
- Hypertension/physiopathology
- Hypertension/prevention & control
- In Vitro Techniques
- Muscle Contraction/drug effects
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/physiology
- Muscle, Smooth, Vascular/physiopathology
- Myocardium/cytology
- Myocardium/pathology
- Phenylephrine/pharmacology
- Potassium Chloride/pharmacology
- Rats
- Rats, Inbred SHR
- Rats, Wistar
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/genetics
- Renal Artery/drug effects
- Renal Artery/physiology
- Renal Artery/physiopathology
- Retroviridae
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Affiliation(s)
- J R Martens
- Department of Physiology, College of Medicine, University of Florida, Gainesville, FL 23610, USA
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Wagner J, Wystrychowski A, Stauss H, Ganten D, Ritz E. Decreased renal haemodynamic response to inhibition of nitric oxide synthase in subtotally nephrectomized rats. Pflugers Arch 1995; 430:181-7. [PMID: 7545811 DOI: 10.1007/bf00374648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
To assess the renal haemodynamic response to manipulations of the nitric oxide (NO) system, we examined subtotally nephrectomized (SNX) rats and control rats (CON) 28 days after their operation. Bolus infusions of the NO synthase inhibitor NG-nitro-L-arginine (L-NA) were given intravenously at doses of 2 mg/kg and 10 mg/kg. Blood pressure was measured intra-arterially, glomerular filtration rate was measured by inulin clearance and fractional changes in renal blood flow (RBF) were determined by a Doppler flow probe. Both doses of L-NA caused a similar and dose-dependent increase in mean blood pressure in both SNX and CON rats. In contrast, the decrease in RBF and the increase in the renovascular resistance index (RVRI) was less in SNX rats as compared to CON rats (RBF = -70.1 +/- 2.2% of baseline vs -52.7 +/- 5.2%, P < 0.01; RVRI = +177 +/- 9% of baseline vs +243 +/- 24%, P < 0.05). These changes were not affected by autonomic blockade (hexamethonium), or by blockade of the angiotensin II receptor (Losartan). The exogenous NO donor sodium nitroprusside (0.5 and 1.5 micrograms.kg-1.min-1) lowered mean blood pressure to a similar degree in SNX and CON rats; in contrast, RVRI decreased less in SNX rats (86.9 +/- 9.2% of baseline) than in CON rats (68.2 +/- 4.6%, P < 0.05). We conclude that the reaction of the renal vasculature to manipulations of the NO system is altered in the SNX rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- J Wagner
- Department of Nephrology, University of Heidelberg, Germany
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36
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Nørrelund H, Christensen KL, Samani NJ, Kimber P, Mulvany MJ, Korsgaard N. Early narrowed afferent arteriole is a contributor to the development of hypertension. Hypertension 1994; 24:301-8. [PMID: 8082936 DOI: 10.1161/01.hyp.24.3.301] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The kidney is probably critically involved in the development of essential hypertension, as in many genetic models of hypertension. We have investigated whether a narrowed renal afferent arteriole is involved in the pathogenesis of hypertension in spontaneously hypertensive rats. Systolic blood pressure of 37 F2 generation spontaneously hypertensive rats/Wistar-Kyoto rats was measured at age 7 weeks. The right kidney was removed, and lumen diameter and media cross-sectional area of the afferent arterioles were measured after having been fixed while relaxed and under a transmural pressure of 100 mm Hg. The uninephrectomized rats continued until age 23 weeks, when mean blood pressure was measured. Mean blood pressure at 23 weeks was negatively correlated with lumen diameter at 7 weeks. Quartile analysis based on lumen diameter at 7 weeks showed that compared with rats in the top lumen diameter quartile, rats in the bottom lumen diameter quartile had a reduced media cross-sectional area at 7 weeks (17%), the same systolic blood pressure at 7 weeks, and an increased (16%) mean blood pressure at 23 weeks. We conclude that in spontaneously hypertensive rats a narrowed lumen of distal afferent arterioles at 7 weeks contributes to later development of increased blood pressure. This reduced lumen could be caused by inhibited renal afferent arteriole growth.
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Affiliation(s)
- H Nørrelund
- Danish Biomembrane Research Centre, Aarhus University, Denmark
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37
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Deschepper CF, Li JS, Schiffrin EL, Welner SA. Hypertension induced by brain grafts from fetal spontaneously hypertensive rats. Hypertension 1994; 23:765-73. [PMID: 8206575 DOI: 10.1161/01.hyp.23.6.765] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hypothalami from fetal rats were grafted into the third ventricle of four strains of adult rats. Grafts from spontaneously hypertensive rats (SHR), in contrast to grafts from Wistar-Kyoto (WKY) rats, induced an elevation of systolic blood pressure and a thickening of the media of resistance arteries, along with corresponding alterations in the contractile properties of these vessels. However, no cardiac hypertrophy was observed. The resistance arteries of rats grafted with hypothalamic from SHR also displayed functional alterations that were similar to what is typically found in the resistance arteries of young prehypertensive SHR, ie, an increase in the sensitivity to cocaine and an impairment in the ability to relax in the presence of acetylcholine. This suggests that the brain may play a causal role in these alterations. Histological examination of sections of brains grafted with previously labeled tissue revealed that (1) there was no brain area that was systematically infiltrated by grafts from SHR and not by grafts from WKY rats; (2) the volume of the transplants appeared larger 2 weeks after the graft than the volume of the tissue originally implanted; and (3) grafts from SHR were slightly larger, displayed more individual foci, and extended farther along the anteroposterior axis than grafts from WKY rats. In addition, glial cultures derived from the hypothalami of SHR had a higher in vitro growth rate than equivalent cultures from WKY rats. It is therefore possible that the ability of brain grafts from SHR to induce hypertension is related to a higher proliferative and/or migratory potential of nonneuronal cells within the hypothalamus.
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Affiliation(s)
- C F Deschepper
- Laboratory of Neurobiology and Vasoactive Peptides, Clinical Research Institute of Montreal, Quebec, Canada
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38
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Samani NJ, Lodwick D, Vincent M, Dubay C, Kaiser MA, Kelly MP, Lo M, Harris J, Sassard J, Lathrop M. A gene differentially expressed in the kidney of the spontaneously hypertensive rat cosegregates with increased blood pressure. J Clin Invest 1993; 92:1099-103. [PMID: 8349793 PMCID: PMC294952 DOI: 10.1172/jci116616] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
The role of the kidney in initiating hypertension has been much debated. Here we demonstrate that a recently identified gene of yet unknown function, termed SA, which is differentially expressed in the kidney of the spontaneously hypertensive rat, cosegregates with an increase in blood pressure in F2 rats derived from a cross of the spontaneously hypertensive rat with normotensive Wistar-Kyoto rats, accounting for 28 and 21% of the genetic variability in systolic and diastolic blood pressures, respectively. Further, the genotype at this locus appears to determine the level of expression of the gene in the kidney. The findings provide strong evidence for a primary genetic involvement of the kidney in hypertension.
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Affiliation(s)
- N J Samani
- Department of Medicine, University of Leicester, United Kingdom
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39
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Skov K, Mulvany MJ, Korsgaard N. Morphology of renal afferent arterioles in spontaneously hypertensive rats. Hypertension 1992; 20:821-7. [PMID: 1452298 DOI: 10.1161/01.hyp.20.6.821] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We present a new perfusion technique that allows arteries down to the level of capillaries to be fixed while relaxed and under a known intravascular pressure. Through a catheter inserted into the right renal artery of 12-week-old male spontaneously hypertensive rats (n = 9) and control Wistar-Kyoto rats (n = 11), the kidney vessels were rinsed with human plasma, relaxed by papaverine, and perfused with a casting resin containing microspheres. The microspheres (12 microns) became trapped in the glomeruli of the kidney and, together with a closing of the venous outflow, they caused the flow through the kidney to stop, so that the intravascular pressure was raised to the level of the input perfusion pressure (100 mm Hg). The resin material was allowed to harden, and the kidney was immersion-fixed and prepared for histomorphometrical investigations. This technique made it possible to measure both the structurally determined lumen diameter and the corresponding media thickness under clearly defined conditions. The lumen diameter of afferent arterioles close to the glomeruli showed a 17% reduction in spontaneously hypertensive rats (15.4 +/- 0.6 microns; mean +/- SEM) compared with Wistar-Kyoto rat arterioles (18.5 +/- 0.3 microns, p < 0.001). However, this was not due to media hypertrophy, because media cross-sectional area was smaller (p < 0.001) in spontaneously hypertensive rats (210 +/- 6 microns 2) compared with Wistar-Kyoto rats (274 +/- 16 microns 2). We conclude that the lumen reduction in renal afferent arterioles in spontaneously hypertensive rats is not the result of an encroachment on the lumen by a hypertrophic media.
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Affiliation(s)
- K Skov
- Danish Biomembrane Research Centre, University of Aarhus, Denmark
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Michel MC, Jäger S, Casto R, Rettig R, Graf C, Printz M, Insel PA, Philipp T, Brodde OE. On the role of renal alpha-adrenergic receptors in spontaneously hypertensive rats. Hypertension 1992; 19:365-70. [PMID: 1313395 DOI: 10.1161/01.hyp.19.4.365] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
We tested the hypothesis that a genetically determined increase in renal alpha-adrenergic receptor density might be a pathophysiologically important factor in the spontaneously hypertensive rat model of genetic hypertension. In a first study, we compared renal alpha 1 and alpha 2-adrenergic receptor density with systolic blood pressure in 45 rats of an F2 generation of Wistar-Kyoto x spontaneously hypertensive rat hybrids but were unable to detect significant cosegregation between either receptor density or blood pressure. In a second study, we determined renal alpha 1- and alpha 2-adrenergic receptor density in Wistar-Kyoto and spontaneously hypertensive rat kidneys that were transplanted into an F1 generation of Wistar-Kyoto x spontaneously hypertensive rat hybrids. Although Wistar-Kyoto kidneys lowered blood pressure in these animals and spontaneously hypertensive rat kidneys increased blood pressure, renal alpha-adrenergic receptor densities were similar in membranes from both types of kidneys. Since rat kidney coexpresses alpha 1A- and alpha 1B-adrenergic receptors, we also investigated whether differential regulation of these two subtypes might conceal ongoing alterations. The alpha 1A/alpha 1B-adrenergic receptor ratio, however, was similar in Wistar-Kyoto rats, spontaneously hypertensive rats, and F1 rats transplanted with a kidney from either strain. Taken together these data do not support the hypothesis that genetically determined alterations of renal alpha-adrenergic receptor numbers play an important role in the development of elevated blood pressure in the spontaneously hypertensive rat.
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Affiliation(s)
- M C Michel
- Department of Medicine, University of Essen, FRG
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Trachtman H, Valderrama E, Futterweit S. Nephrotoxicity of allopurinol is enhanced in experimental hypertension. Hypertension 1991; 17:194-202. [PMID: 1991652 DOI: 10.1161/01.hyp.17.2.194] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Hyperuricemia is present in 20-40% of pediatric and adult patients with essential hypertension. This metabolic abnormality may represent an additional risk factor for the development of cardiovascular disease. Therefore, we performed the following studies to determine 1) whether hyperuricemia is more prevalent in the spontaneously hypertensive rat (SHR) and 2) whether allopurinol treatment has a beneficial effect on the development of hypertension in this strain, based on its capacity to lower the serum uric acid concentration and to act as an antioxidant agent. SHR and control Wistar-Kyoto (WKY) rats were assigned to two groups, one given tap water to drink and the other provided water containing allopurinol (400 mg/l) to furnish an approximate daily dose equal to 100 mg/kg body wt. This treatment was maintained for 15 weeks. The serum uric acid levels were similar in untreated SHR and WKY rats (1.85 +/- 0.10 versus 1.66 +/- 0.14 mg/dl; p = 0.28). In the control WKY rat strain, allopurinol therapy did not adversely affect weight gain or hematocrit and did not cause an increase in mortality. It resulted in a moderate decrement in kidney function (creatinine clearance: allopurinol-treated group 0.32 +/- 0.09 versus control group 0.46 +/- 0.04 ml/min/100 g body wt, in conjunction with mild-to-moderate tubulointerstitial inflammation (allopurinol-treated group 0.9 +/- 0.4 versus control group 0).(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- H Trachtman
- Department of Pediatrics Division of Nephrology, Schneider Children's Hospital, New Hyde Park, NY 11042
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