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Culshaw G, Binnie D, Dhaun N, Hadoke P, Bailey M, Webb D. The acute pressure natriuresis response is suppressed by selective ETA receptor blockade. Clin Sci (Lond) 2021; 136:CS20210937. [PMID: 34918049 PMCID: PMC8734438 DOI: 10.1042/cs20210937] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/25/2021] [Accepted: 12/16/2021] [Indexed: 11/17/2022]
Abstract
Hypertension is a major risk factor for cardiovascular disease. In a significant minority of people, it develops when salt intake is increased (salt-sensitivity). It is not clear whether this represents impaired vascular function or disruption to the relationship between blood pressure (BP) and renal salt-handling (pressure natriuresis, PN). Endothelin-1 (ET-1) regulates BP via ETA and ETB receptor subtypes. Blockade of ETA receptors reduces BP, but promotes sodium retention by an unknown mechanism. ETB blockade increases both BP and sodium retention. We hypothesised that ETA blockade promotes sodium and water retention by suppressing PN. We also investigated whether suppression of PN might reflect off-target ETB blockade. Acute PN was induced by sequential arterial ligation in male Sprague Dawley rats. Intravenous atrasentan (ETA antagonist, 5mg/kg) halved the normal increase in medullary perfusion and reduced sodium and water excretion by >60%. This was not due to off-target ETB blockade because intravenous A-192621 (ETB antagonist, 10mg/kg) increased natriuresis by 50% without modifying medullary perfusion. In a separate experiment in salt-loaded rats monitored by radiotelemetry, oral atrasentan reduced systolic and diastolic BP by ~10mmHg, but additional oral A-192621 reversed these effects. Endogenous ETA stimulation has natriuretic effects mediated by renal vascular dilation while endogenous ETB stimulation in the kidney has antinatriuretic effects via renal tubular mechanisms. Pharmacological manipulation of vascular function with ET antagonists modifies the BP set-point, but even highly selective ETA antagonists attenuate PN, which may be associated with salt and water retention.
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Affiliation(s)
- Geoffrey J. Culshaw
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - David Binnie
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Neeraj Dhaun
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Patrick W.F. Hadoke
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - Matthew A. Bailey
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
| | - David J. Webb
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen’s Medical Research Institute, The University of Edinburgh, 47 Little France Crescent, Edinburgh EH16 4TJ, U.K
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Vatakencherry RMJ, Saraswathy L. Association between vitamin D and hypertension in people coming for health check up to a tertiary care centre in South India. J Family Med Prim Care 2019; 8:2061-2067. [PMID: 31334180 PMCID: PMC6618207 DOI: 10.4103/jfmpc.jfmpc_236_19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2019] [Revised: 03/20/2019] [Accepted: 04/09/2019] [Indexed: 12/13/2022] Open
Abstract
INTRODUCTION Vitamin D has many effects apart from its role in calcium metabolism and bone health. Vitamin D is derived from endogenous ultraviolet-B induced vitamin D synthesis in the skin, and the current high prevalence of vitamin D deficiency in India, can be attributed to lifestyle related low sunlight exposure. Identification of the vitamin D receptor (VDR) in almost all human cells, suggests a role in extra skeletal diseases. Studies have shown that vitamin D deficiency is an independent risk factor for hypertension. AIM To evaluate the association between vitamin D and hypertension in people coming for health check up to a tertiary care center in South India. MATERIALS AND METHODS Study was carried out as a cross sectional study in a tertiary care hospital in South India. Participants (520) were both males and females (337 males and 183 females), between the age group of 20-60 years attending the comprehensive health check up clinic of our hospital. STATISTICAL ANALYSIS Statistical analysis was done using IBM SPSS statistics 20.0. RESULTS Severe vitamin D deficiency was highly prevalent in people with hypertension than in people without hypertension (P value <0.001). CONCLUSION Since India is a tropical country, till recently it was believed that vitamin D deficiency and its ill effects are uncommon. But it was found that, vitamin D deficiency was highly prevalent in people with hypertension in South India, emphasizing the need of early vitamin D supplementation. Therefore, to reduce cardiovascular morbidity, early identification of vitamin D deficiency and appropriate vitamin D supplementation may be of primary importance in population, especially like ours, having high prevalence.
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Affiliation(s)
- Rose Mary J. Vatakencherry
- Department of Physiology, Amrita School of Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham University, Kochi, Kerala
| | - L Saraswathy
- Department of Physiology, Amrita School of Medicine, Amrita Institute of Medical Sciences, Amrita Vishwa Vidyapeetham University, Kochi, Kerala
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Liu HB, Zhang J, Sun YY, Li XY, Jiang S, Liu MY, Shi J, Song BL, Zhao D, Ma HP, Zhang ZR. Dietary salt regulates epithelial sodium channels in rat endothelial cells: adaptation of vasculature to salt. Br J Pharmacol 2015; 172:5634-46. [PMID: 25953733 DOI: 10.1111/bph.13185] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2014] [Revised: 04/03/2015] [Accepted: 04/26/2015] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE The epithelial sodium channel (ENaC) is expressed in vascular endothelial cells and is a negative modulator of vasodilation. However, the role of endothelial ENaCs in salt-sensitive hypertension remains unclear. Here, we have investigated how endothelial ENaCs in Sprague-Dawley (SD) rats respond to high-salt (HS) challenge. EXPERIMENTAL APPROACH BP and plasma aldosterone levels were measured. We used patch-clamp technique to record ENaC activity in split-open mesenteric arteries (MAs). Western blot and Griess assay were used to detect expression of α-ENaCs, eNOS and NO. Vasorelaxation in second-order MAs was measured with wire myograph assays. KEY RESULTS Functional ENaCs were observed in endothelial cells and their activity was significantly decreased after 1 week of HS diet. After 3 weeks of HS diet, ENaC expression was also reduced. When either ENaC activity or expression was reduced, endothelium-dependent relaxation (EDR) of MAs, in response to ACh, was enhanced. This enhancement of EDR was mimicked by amiloride, a blocker of ENaCs. By contrast, HS diet significantly increased contractility of MAs, accompanied by decreased eNOS activity and NO levels. However, ACh-induced release of NO was much higher in MAs isolated from HS rats than those from NS rats. CONCLUSIONS AND IMPLICATIONS HS intake increased the BP of SD rats, but simultaneously enhanced EDR by reducing ENaC activity and expression due to feedback inhibition. Therefore, ENaCs may play an important role in endothelial cells allowing the vasculature to adapt to HS conditions.
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Affiliation(s)
- Hui-Bin Liu
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Jun Zhang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ying-Ying Sun
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Xin-Yuan Li
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Shuai Jiang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Ming-Yu Liu
- Department of Pharmacology, Harbin Medical University, Harbin, China
| | - Jing Shi
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Bin-Lin Song
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - Dan Zhao
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
| | - He-Ping Ma
- Department of Physiology, Emory University School of Medicine, Atlanta, GA, USA
| | - Zhi-Ren Zhang
- Departments of Clinical Pharmacy and Cardiology, Institute of Clinical Pharmacy, the 2nd Affiliated Hospital, Harbin Medical University, Key Laboratories of Education Ministry for Myocardial Ischemia Mechanism and Treatment, Harbin, China
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Kienreich K, Grübler M, Tomaschitz A, Schmid J, Verheyen N, Rutters F, Dekker JM, Pilz S. Vitamin D, arterial hypertension & cerebrovascular disease. Indian J Med Res 2013; 137:669-79. [PMID: 23703334 PMCID: PMC3724247] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Vitamin D is mainly derived from endogenous ultraviolet-B induced vitamin D synthesis in the skin, and the current high prevalence of vitamin D deficiency can, therefore, largely be attributed to lifestyle related low sunlight exposure. Regulation of bone and mineral metabolism is a classic vitamin D effect, but the identification of the vitamin D receptor (VDR) in almost all human cells suggests a role for vitamin D also in extra-skeletal diseases. Experimental studies demonstrated several antihypertensive and vascular protective effects of vitamin D, such as suppression of the renin angiotensin aldosterone system, beneficial modulation of classic cardiovascular risk factors, and anti-atherosclerotic properties including improvements of endothelial function. Additional neuroprotective actions of vitamin D have also been reported. In line with this, epidemiological studies have largely shown that vitamin D deficiency is an independent risk factor for arterial hypertension and strokes. Data from randomized controlled trials (RCTs) are, however, limited and less promising, with currently no confirmation that vitamin D reduces stroke incidence. Whereas some RCTs suggest that vitamin D supplementation might modestly reduce blood pressure, this has not been consistently observed in all studies. It is, therefore, premature to recommend vitamin D supplementation for the prevention and treatment of arterial hypertension and stroke. Nevertheless, the fact that patients with arterial hypertension and cerebrovascular disease are at a relatively high risk of vitamin D deficiency, and therewith associated musculoskeletal diseases can serve as a rationale for the evaluation, prevention and treatment of vitamin D deficiency in these patients.
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Affiliation(s)
- Katharina Kienreich
- Department of Internal Medicine, Division of Endocrinology & Metabolism, Medical University of Graz, Austria
| | - Martin Grübler
- Department of Internal Medicine, Division of Endocrinology & Metabolism, Medical University of Graz, Austria
| | - Andreas Tomaschitz
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, Austria
| | - Johannes Schmid
- Department of Internal Medicine, Division of Endocrinology & Metabolism, Medical University of Graz, Austria
| | - Nicolas Verheyen
- Department of Internal Medicine, Division of Cardiology, Medical University of Graz, Austria
| | - Femke Rutters
- Department of Epidemiology & Biostatistics, EMGO Institute for Health & Care Research, VU University Medical Centre, Amsterdam, The Netherlands
| | - Jacqueline M. Dekker
- Department of Epidemiology & Biostatistics, EMGO Institute for Health & Care Research, VU University Medical Centre, Amsterdam, The Netherlands
| | - Stefan Pilz
- Department of Internal Medicine, Division of Endocrinology & Metabolism, Medical University of Graz, Austria,Department of Epidemiology & Biostatistics, EMGO Institute for Health & Care Research, VU University Medical Centre, Amsterdam, The Netherlands,Reprint requests: Dr Stefan Pilz, Department of Epidemiology & Biostatistics, EMGO Institute for Health & Care Research VU University Medical Centre Amsterdam, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands e-mail: ,
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