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Vara-Messler M, Mukdsi JH, Osieki NI, Benizio E, Repossi GM, Ajayi EIO, García NH. Eicosapentaenoic acid prevents salt sensitivity in diabetic rats and decreases oxidative stress. Nutrition 2019; 72:110644. [PMID: 32044546 DOI: 10.1016/j.nut.2019.110644] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2019] [Revised: 11/02/2019] [Accepted: 11/02/2019] [Indexed: 01/06/2023]
Abstract
OBJECTIVES Salt sensitivity (SS) is associated with increased cardiovascular risk in patients with Type 2 diabetes mellitus (T2-DM) due to an increase in renal oxidation. ω-3 polyunsaturated fatty acids have shown antioxidant effects, but a typical Western diet contains limited content. In particular, ω-3 polyunsaturated fatty acids are able to activate nuclear factor erythroid 2-related factor 2 (Nrf-2) to prevent diabetes mellitus-related complications by mitigating oxidative stress. Therefore, we hypothesized that eicosapentaenoic acid (EPA; ω-3) modulates SS in rats with T2-DM by decreasing renal oxidative stress via Nrf-2 activation and enhancing the antiinflammatory response via interleukin (IL) 6 modulation. METHODS Three-month-old male rats (n = 40) were fed with a Normal Na-diet (NNaD) and randomly selected into four groups: Healthy Wistar nondiabetic rats (Wi), diabetic controls (eSS), arachidonic acid-treated eSS (AA; ω-6), and EPA-treated eSS (ω-3). After 1 year, rats were placed in metabolic cages for 7 d and fed a NNaD, followed by a 7-d period with a High Na-diet (HNaD). Systolic blood pressure, body weight, serum IL-6 and reactive oxygen species (ROS) levels were determined at the end of each 7-d period. Glycated hemoglobin (HbA1c), triacylglycerol, creatinine, and cholesterol levels were determined. ROS levels and Nrf-2 expression in kidney lysates were also assayed. Histologic changes were evaluated. A t test or analysis of variance was used for the statistical analysis. RESULTS After a HNaD, systolic blood pressure increased in both the control eSS and AA groups, but not in the EPA and Wi groups. However, HbA1c levels remained unchanged by the treatments, which suggests that the observed beneficial effect was independent of HbA1c levels. The IL-6 levels were higher in the eSS and AA groups, but remained unaltered in EPA and Wi rats after a HNaD diet. Interestingly, EPA protected against serum ROS in rats fed the HNaD, whereas AA did not. In kidney lysates, ROS decreased significantly in the EPA group compared with the eSS group, and Nrf-2 expression was consistently higher compared with the AA and eSS groups. Diabetic rats presented focal segmental sclerosis, adherence to Bowman capsule, and mild-to-moderate interstitial fibrosis. EPA and AA treatment prevented kidney damage. CONCLUSIONS An adequate ω3-to-ω6 ratio prevents SS in diabetic rats by a mechanism that is independent of glucose metabolism but associated with the prevention of renal oxidative stress generation. These data suggest that EPA antioxidant properties may prevent the development of hypertension or kidney damage.
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Affiliation(s)
| | - Jorge H Mukdsi
- Instituto de Investigaciones en Ciencias de la Salud de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Natalia I Osieki
- Instituto de Investigaciones en Ciencias de la Salud de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina; Instituto de Biología Celular, Cátedra de Biología Celular, Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Evangelina Benizio
- Instituto de Investigaciones en Ciencias de la Salud de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina; Instituto de Biología Celular, Cátedra de Biología Celular, Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Gastón M Repossi
- Instituto de Investigaciones en Ciencias de la Salud de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina; Instituto de Biología Celular, Cátedra de Biología Celular, Histología y Embriología, Facultad de Ciencias Médicas, Universidad Nacional de Córdoba, Córdoba, Argentina
| | - Ebenezer I O Ajayi
- DC&ONID, Biochemistry Department, Osun State University, Osogbo, Nigeria; IMMF-INIMEC-Universidad Nacional de Córdoba, Consejo Nacional de Investigaciones Científicas y Técnicas, Córdoba, Argentina
| | - Néstor H García
- Instituto de Investigaciones en Ciencias de la Salud de Córdoba, Universidad Nacional de Córdoba, Córdoba, Argentina.
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L-arginine supplementation lowers blood pressure, protein excretion and plasma lipid profile in experimental salt-induced hypertension in pregnancy: Relevance to preeclampsia. PATHOPHYSIOLOGY 2019; 26:191-197. [DOI: 10.1016/j.pathophys.2019.02.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Revised: 02/08/2019] [Accepted: 02/12/2019] [Indexed: 12/18/2022] Open
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Vallon V, Unwin R, Inscho EW, Leipziger J, Kishore BK. Extracellular Nucleotides and P2 Receptors in Renal Function. Physiol Rev 2019; 100:211-269. [PMID: 31437091 DOI: 10.1152/physrev.00038.2018] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The understanding of the nucleotide/P2 receptor system in the regulation of renal hemodynamics and transport function has grown exponentially over the last 20 yr. This review attempts to integrate the available data while also identifying areas of missing information. First, the determinants of nucleotide concentrations in the interstitial and tubular fluids of the kidney are described, including mechanisms of cellular release of nucleotides and their extracellular breakdown. Then the renal cell membrane expression of P2X and P2Y receptors is discussed in the context of their effects on renal vascular and tubular functions. Attention is paid to effects on the cortical vasculature and intraglomerular structures, autoregulation of renal blood flow, tubuloglomerular feedback, and the control of medullary blood flow. The role of the nucleotide/P2 receptor system in the autocrine/paracrine regulation of sodium and fluid transport in the tubular and collecting duct system is outlined together with its role in integrative sodium and fluid homeostasis and blood pressure control. The final section summarizes the rapidly growing evidence indicating a prominent role of the extracellular nucleotide/P2 receptor system in the pathophysiology of the kidney and aims to identify potential therapeutic opportunities, including hypertension, lithium-induced nephropathy, polycystic kidney disease, and kidney inflammation. We are only beginning to unravel the distinct physiological and pathophysiological influences of the extracellular nucleotide/P2 receptor system and the associated therapeutic perspectives.
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Affiliation(s)
- Volker Vallon
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Robert Unwin
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Edward W Inscho
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Jens Leipziger
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
| | - Bellamkonda K Kishore
- Departments of Medicine and Pharmacology, University of California San Diego & VA San Diego Healthcare System, San Diego, California; Centre for Nephrology, Division of Medicine, University College London, London, United Kingdom; IMED ECD CVRM R&D, AstraZeneca, Gothenburg, Sweden; Department of Medicine, Division of Nephrology, The University of Alabama at Birmingham, Birmingham, Alabama; Department of Biomedicine/Physiology, Aarhus University, Aarhus, Denmark; Departments of Internal Medicine and Nutrition and Integrative Physiology, and Center on Aging, University of Utah Health & Nephrology Research, VA Salt Lake City Healthcare System, Salt Lake City, Utah
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Piper sarmentosum Leaves Aqueous Extract Attenuates Vascular Endothelial Dysfunction in Spontaneously Hypertensive Rats. EVIDENCE-BASED COMPLEMENTARY AND ALTERNATIVE MEDICINE 2019; 2019:7198592. [PMID: 31485247 PMCID: PMC6710744 DOI: 10.1155/2019/7198592] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Revised: 07/03/2019] [Accepted: 07/14/2019] [Indexed: 02/05/2023]
Abstract
Piper sarmentosum is a tropical plant in Southeast Asia known for its traditional use in curing various ailments including hypertension. Previous research works have provided evidence for the herb's antihypertensive property. However, the exact mechanisms involved are still in question. The present study investigated the effects of Piper sarmentosum leaves aqueous extract (PSAE) treatment on vascular endothelin system in spontaneously hypertensive rats (SHRs). Four groups of SHRs were treated for 28 consecutive days, with negative and positive control groups receiving distilled water and 3 mg/kg perindopril, respectively. Another two groups are the treatment groups, which received PSAE and combination of 1.5 mg/kg perindopril and PSAE. Weekly measurements of blood pressure showed that PSAE significantly reduced the systolic, diastolic, and mean arterial pressures (P < 0.05) of the rats. PSAE also increased mesenteric artery nitric oxide (NO) level (P < 0.05) and reduced endothelin-1 (ET-1) level (P < 0.05) in the treatment groups. Our results demonstrate that oral administration of PSAE reduced blood pressure in SHRs by reducing the ET-1 level while increasing NO production.
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55
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Legrand M, Sonneville R. Understanding the renal response to brain injury. Intensive Care Med 2019; 45:1112-1115. [PMID: 31312853 DOI: 10.1007/s00134-019-05685-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Accepted: 07/02/2019] [Indexed: 12/20/2022]
Affiliation(s)
- Matthieu Legrand
- AP-HP, GH St-Louis-Lariboisière, Department of Anesthesiology and Critical Care and Burn Unit, St-Louis Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France. .,F-CRIN INICRCT Network, Nancy, France. .,Department of Intensive Care Medicine and Infectious Diseases, Bichat-Claude Bernard University Hospital, AP-HP, Paris, France.
| | - Romain Sonneville
- Department of Intensive Care Medicine and Infectious Diseases, Bichat-Claude Bernard University Hospital, AP-HP, Paris, France.,UMR1148, LVTS, Sorbonne Paris Cité, Inserm/Paris Diderot University, Paris, France
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56
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Franco M, Pérez-Méndez O, Kulthinee S, Navar LG. Integration of purinergic and angiotensin II receptor function in renal vascular responses and renal injury in angiotensin II-dependent hypertension. Purinergic Signal 2019; 15:277-285. [PMID: 31183668 DOI: 10.1007/s11302-019-09662-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Accepted: 05/30/2019] [Indexed: 12/24/2022] Open
Abstract
Glomerular arteriolar vasoconstriction and tubulointerstitial injury are observed before glomerular damage occurs in models of hypertension. High interstitial ATP concentrations, caused by the increase in arterial pressure, alter renal mechanisms involved in the long-term control of blood pressure, autoregulation of glomerular filtration rate and blood flow, tubuloglomerular feedback (TGF) responses, and sodium excretion. Elevated ATP concentrations and augmented expression of P2X receptors have been demonstrated under a genetic background or induction of hypertension with vasoconstrictor peptides. In addition to the alterations of the microcirculation in the hypertensive kidney, the vascular actions of elevated intrarenal angiotensin II levels may be mitigated by the administration of broad purinergic P2 antagonists or specific P2Y12, P2X1, and P2X7 receptor antagonists. Furthermore, the prevention of tubulointerstitial infiltration with immunosuppressor compounds reduces the development of salt-sensitive hypertension, indicating that tubulointerstitial inflammation is essential for the development and maintenance of hypertension. Inflammatory cells also express abundant purinergic receptors, and their activation by ATP induces cytokine and growth factor release that in turn contributes to augment tubulointerstitial inflammation. Collectively, the evidence suggests a pathophysiological activation of purinergic P2 receptors in angiotensin-dependent hypertension. Coexistent increases in intrarenal angiotensin II and activates Ang II AT1 receptors, which interacts with over-activated purinergic receptors in a complex manner, suggesting convergence of their post-receptor signaling processes.
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Affiliation(s)
- Martha Franco
- Department of Nephrology, Renal Pathophysiology Laboratory, Instituto Nacional de Cardiología "Ignacio Chávez", Juan Badiano No.1, 14080, Mexico City, DF, Mexico.
| | - Oscar Pérez-Méndez
- Department Molecular Biology, Instituto Nacional de Cardiología "Ignacio Chávez", Mexico City, Mexico
| | - Supaporn Kulthinee
- Department of Physiology and Hypertension and Renal Center, Tulane University School of Medicine, New Orleans, LA, USA.,Department of Cardiovascular and Thoracic Technology, Chulabhorn International College of Medicine, Thammasat University, Rangsit, Pathum Thani, Thailand
| | - L Gabriel Navar
- Department of Physiology and Hypertension and Renal Center, Tulane University School of Medicine, New Orleans, LA, USA
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Razavi AC, Potts KS, Kelly TN, Bazzano LA. Sex, gut microbiome, and cardiovascular disease risk. Biol Sex Differ 2019; 10:29. [PMID: 31182162 PMCID: PMC6558780 DOI: 10.1186/s13293-019-0240-z] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2019] [Accepted: 05/13/2019] [Indexed: 02/07/2023] Open
Abstract
Key differences exist between men and women in the determinants and manifestations of cardiovascular and cardiometabolic diseases. Recently, gut microbiome-host relations have been implicated in cardiovascular disease and associated metabolic conditions; therefore, gut microbiota may be key mediators or modulators driving the observed sexual dimorphism in disease onset and progression. While current evidence regarding pure physiological sex differences in gut microbiome composition is modest, robust research suggests that gut microbiome-dependent metabolites may interact with important biological pathways under sex hormone control, including toll-like receptor and flavin monooxygenase signaling. Here, we review key sex differences in gut microbiome interactions with four primary determinants of cardiovascular disease, impaired glucose regulation, dyslipidemia, hypertension, and obesity. Through this process, we propose important sex differences in downstream metabolic pathways that may be at the interface of the gut microbiome and cardiovascular disease.
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Affiliation(s)
- Alexander C. Razavi
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA USA
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2000, New Orleans, LA 70112 USA
| | - Kaitlin S. Potts
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2000, New Orleans, LA 70112 USA
| | - Tanika N. Kelly
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2000, New Orleans, LA 70112 USA
| | - Lydia A. Bazzano
- Department of Medicine, Tulane University School of Medicine, New Orleans, LA USA
- Department of Epidemiology, Tulane University School of Public Health and Tropical Medicine, 1440 Canal Street, Suite 2000, New Orleans, LA 70112 USA
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58
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Oloyo AK, Imaga NO, Fatope Y, Sofola OA. Sex differences in cardiac and renal responses to a high salt diet in Sprague-Dawley rats. Heliyon 2019; 5:e01665. [PMID: 31193051 PMCID: PMC6514751 DOI: 10.1016/j.heliyon.2019.e01665] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2018] [Revised: 04/09/2019] [Accepted: 05/02/2019] [Indexed: 01/11/2023] Open
Abstract
High dietary salt intake is an important risk factor for cardiovascular and renal diseases. However, sexual disparity exists in the response of target organs to high salt diet (HSD). To determine how sex affects cardiac and renal functions' response to HSD, 20 weanling Sprague-Dawley rats (10 males and 10 females) were divided into 4 groups of 5 rats each. The rats were fed a normal diet (0.3% NaCl) or HSD (8% NaCl) for 12 weeks. Fluid balance (FB) was determined from 24 hrs water intake and voided urine. Blood pressure (BP) was measured via arterial cannulation under anesthesia (25% w/v urethane and 1% w/v α-chloralose; 5 ml/kg, i.p). Serum levels of troponin I, aminotransaminases, creatinine, urea, uric acid and electrolytes as well as urinary concentration of albumin, creatinine, and electrolytes were measured using appropriate assay kits. Values are presented as mean ± S.E.M, compared by two-way ANOVA and Bonferroni post Hoc test. In the male rat, HSD significantly increased BP, serum: Troponin I, LDH and sodium (p < 0.05), urinary: albumin, sodium, potassium and FB (p < 0.05). In the female rat, HSD increased BP, serum: troponin I, LDH, sodium and creatinine clearance (p < 0.05), urinary: albumin, sodium and potassium (p < 0.01). However, HSD increased more, the BP, serum: Troponin I, LDH, urinary albumin and FB in male rats, while HSD increased urinary sodium more in female rats. Basal values in male vs. female of serum LDH and urinary albumin were significantly different. Thus, sex plays an important role in the response of the heart and kidney to salt stress.
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Affiliation(s)
- Ahmed Kolade Oloyo
- Department of Physiology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Surulere, Nigeria
| | - Ngozi O.A. Imaga
- Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Surulere, Nigeria
| | - Yemisi Fatope
- Department of Biochemistry, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Surulere, Nigeria
| | - Olusoga A. Sofola
- Department of Physiology, Faculty of Basic Medical Sciences, College of Medicine, University of Lagos, Surulere, Nigeria
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59
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Anchietea pyrifolia A. St.-Hil. as a Cardiovascular-Endowed Species: A Whole-Biological Investigation. J Med Food 2019; 22:393-407. [DOI: 10.1089/jmf.2018.0140] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
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60
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Ames MK, Atkins CE, Pitt B. The renin-angiotensin-aldosterone system and its suppression. J Vet Intern Med 2019; 33:363-382. [PMID: 30806496 PMCID: PMC6430926 DOI: 10.1111/jvim.15454] [Citation(s) in RCA: 208] [Impact Index Per Article: 41.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2018] [Accepted: 01/30/2019] [Indexed: 12/11/2022] Open
Abstract
Chronic activation of the renin-angiotensin-aldosterone system (RAAS) promotes and perpetuates the syndromes of congestive heart failure, systemic hypertension, and chronic kidney disease. Excessive circulating and tissue angiotensin II (AngII) and aldosterone levels lead to a pro-fibrotic, -inflammatory, and -hypertrophic milieu that causes remodeling and dysfunction in cardiovascular and renal tissues. Understanding of the role of the RAAS in this abnormal pathologic remodeling has grown over the past few decades and numerous medical therapies aimed at suppressing the RAAS have been developed. Despite this, morbidity from these diseases remains high. Continued investigation into the complexities of the RAAS should help clinicians modulate (suppress or enhance) components of this system and improve quality of life and survival. This review focuses on updates in our understanding of the RAAS and the pathophysiology of AngII and aldosterone excess, reviewing what is known about its suppression in cardiovascular and renal diseases, especially in the cat and dog.
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Affiliation(s)
- Marisa K Ames
- Department of Clinical Sciences, College of Veterinary Medicine, Colorado State University, Fort Collins, Colorado
| | - Clarke E Atkins
- Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina
| | - Bertram Pitt
- Department of Medicine, University of Michigan School of Medicine, Ann Arbor, Michigan
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61
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Ding JJ, Lin SH, Lai JY, Wu TW, Huang JL, Chung HT, Tseng MH. Unilateral renal artery stenosis presented with hyponatremic-hypertensive syndrome - case report and literature review. BMC Nephrol 2019; 20:64. [PMID: 30791890 PMCID: PMC6385391 DOI: 10.1186/s12882-019-1246-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 02/01/2019] [Indexed: 12/20/2022] Open
Abstract
Background Renal artery stenosis is one of the secondary causes of pediatric hypertension. Cases with critical unilateral renal artery stenosis manifesting with the hyponatremic hypertensive syndrome are rare and a comprehensive description of this disorder in the pediatric population is lacking in the literature. Case presentation We describe a 4-year-old boy who presented with severe hypertension, profound hyponatremia, hypokalemia, nephrotic range proteinuria, and polyuria. Distinctly, the diagnosis of hyponatremic hypertensive syndrome secondary to unilateral renal artery stenosis was confirmed in light of laboratory and radiographic findings of severe natriuresis, elevated renin, and unilateral small kidney. Two weeks following nephrectomy, there was resolution of hyponatremia, hypokalemia, nephrotic range proteinuria and hypertension. Conclusions Findings of hyponatremia, hypokalemia, hypertension, polyuria, and unilateral renal hypoplasia can be attributed to a unifying pathology of unilateral renal artery stenosis. Electronic supplementary material The online version of this article (10.1186/s12882-019-1246-9) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jhao-Jhuang Ding
- Division of Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, No 5, Fu-Shing ST., Kwei-Shan, 33305, Taoyuan, Taiwan.,Department of Pediatrics, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Shih-Hua Lin
- Division of Nephrology, Department of Medicine, National Defense Medical Center, Tri-Service General Hospital, Taipei, Taiwan
| | - Jin-Yao Lai
- Division of Pediatric Surgery, Department of Surgery, Chang Gung Memorial Hospital, Chang Gung University, College of Medicine, Linkou, Taiwan
| | - Tai-Wei Wu
- Department of Pediatrics, Fetal and Neonatal Institute, Division of Neonatology Children's Hospital Los Angeles, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Jing-Long Huang
- Division of Allergy, Asthma and Rheumatology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Hung-Tao Chung
- Division of Cardiology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, Taoyuan, Taiwan
| | - Min-Hua Tseng
- Division of Nephrology, Department of Pediatrics, Chang Gung Memorial Hospital and Chang Gung University, No 5, Fu-Shing ST., Kwei-Shan, 33305, Taoyuan, Taiwan.
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62
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Culshaw GJ, Costello HM, Binnie D, Stewart KR, Czopek A, Dhaun N, Hadoke PWF, Webb DJ, Bailey MA. Impaired pressure natriuresis and non-dipping blood pressure in rats with early type 1 diabetes mellitus. J Physiol 2019; 597:767-780. [PMID: 30537108 PMCID: PMC6355628 DOI: 10.1113/jp277332] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 11/28/2018] [Indexed: 01/26/2023] Open
Abstract
KEY POINTS Type 1 diabetes mellitus increases cardiovascular risk; hypertension amplifies this risk, while pressure natriuresis regulates long-term blood pressure. We induced type 1 diabetes in rats by streptozotocin injection and demonstrated a substantial impairment of pressure natriuresis: acute increases in blood pressure did not increase renal medullary blood flow, tubular sodium reabsorption was not downregulated, and proximal tubule sodium reabsorption, measured by lithium clearance, was unaffected. Insulin reduced blood glucose in diabetic rats, and rescued the pressure natriuresis response without influencing lithium clearance, but did not restore medullary blood flow. Radiotelemetry showed that diastolic blood pressure was increased in diabetic rats, and its diurnal variation was reduced. Increases in medullary blood flow and decreases in distal tubule sodium reabsorption that offset acute rises in BP are impaired in early type 1 diabetes, and this impairment could be a target for preventing hypertension in type 1 diabetes. ABSTRACT Type 1 diabetes mellitus (T1DM) substantially increases cardiovascular risk, and hypertension amplifies this risk. Blood pressure (BP) and body sodium homeostasis are linked. T1DM patients have increased total exchangeable sodium, correlating directly with BP. Pressure natriuresis is an important physiological regulator of BP. We hypothesised that pressure natriuresis would be impaired, and BP increased, in the early phase of T1DM. Male Sprague-Dawley rats were injected with streptozotocin (30-45 mg/kg) or citrate vehicle. After 3 weeks, pressure natriuresis was induced by serial arterial ligation. In non-diabetic controls, this increased fractional excretion of sodium from ∼1% to ∼25% of the filtered load (P < 0.01); in T1DM rats, the response was significantly blunted, peaking at only ∼3% (P < 0.01). Mechanistically, normal lithium clearance suggested that distal tubule sodium reabsorption was not downregulated with increased BP in T1DM rats. The pressure dependence of renal medullary perfusion, considered a key factor in the integrated response, was abolished. Insulin therapy rescued the natriuretic response in diabetic rats, restoring normal downregulation of tubular sodium reabsorption when BP was increased. However, the pressure dependence of medullary perfusion was not restored, suggesting persistent vascular dysfunction despite glycaemic control. Radiotelemetry showed that T1DM did not affect systolic BP, but mean diastolic BP was ∼5 mmHg higher than in non-diabetic controls (P < 0.01), and normal diurnal variation was reduced. In conclusion, functional impairment of renal sodium and BP homeostasis is an early manifestation of T1DM, preceding hypertension and nephropathy. Early intervention to restore pressure natriuresis in T1DM may complement reductions in cardiovascular risk achieved with glycaemic control.
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Affiliation(s)
- Geoffrey J. Culshaw
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Hannah M. Costello
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - David Binnie
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Kevin R. Stewart
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Alicja Czopek
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Neeraj Dhaun
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Patrick W. F. Hadoke
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - David J. Webb
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
| | - Matthew A. Bailey
- The British Heart Foundation Centre for Cardiovascular ScienceThe Queen's Medical Research InstituteThe University of Edinburgh47 Little France CrescentEdinburghEH16 4TJUK
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Tolouei SEL, Tirloni CAS, Palozi RAC, Schaedler MI, Guarnier LP, Silva AO, de Almeida VP, Budel JM, Souza RIC, Dos Santos AC, Dos Santos VS, Silva DB, Dalsenter PR, Gasparotto Junior A. Celosia argentea L. (Amaranthaceae) a vasodilator species from the Brazilian Cerrado - An ethnopharmacological report. JOURNAL OF ETHNOPHARMACOLOGY 2019; 229:115-126. [PMID: 30248350 DOI: 10.1016/j.jep.2018.09.027] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Revised: 08/18/2018] [Accepted: 09/20/2018] [Indexed: 06/08/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Celosia argentea L. (Amaranthaceae), popularly known as "crista de galo", is used in folk medicine due to its diuretic and hypotensive effects. However, there are no reports in the literature regarding its pharmacological effects on the cardiovascular system as well as no data proving the safety of this species. AIM To perform a detailed ethnopharmacological investigation of the ethanol soluble fraction from C. argentea (ESCA) using male and female Wistar rats. MATERIAL AND METHODS Firstly, a morpho-anatomical characterization was performed to determine the quality control parameters for the identification of the species under investigation. Then, the ethanol extract was obtained and chemically characterized by LC-DAD-MS. Furthermore, an oral acute toxicity study was performed in female Wistar rats. Finally, the possible diuretic and hypotensive effects of three different doses of ESCA (30, 100 and 300 mg/kg) were evaluated in male Wistar rats. Besides, the vasodilatory response of ESCA in mesenteric vascular beds (MVBs) and its involvement with nitric oxide/cGMP and prostaglandin/cAMP pathways as well as potassium channels were evaluated. RESULTS The main secondary metabolites present in ESCA were phenolic compounds, megastigmanes and triterpenoid saponins. ESCA caused no toxic effects in female rats nor increased urinary excretion in male rats after acute administration. However, ESCA significantly increased the renal elimination of potassium and chloride, especially at the end of 24 h after administration. Intermediary dose (100 mg/kg) of ESCA was able to promote significant acute hypotension and bradycardia. Moreover, its cardiovascular effects appear to be involved with the voltage-dependent K+ channels activation in MVBs. CONCLUSION This study has brought new scientific evidence of preclinical efficacy of C. argentea as a hypotensive agent in normotensive rats. Apparently, these effects are involved with the activation of the voltage-sensitive K+ channels contributing to the reduction of peripheral vascular resistance and cardiac output.
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Affiliation(s)
| | - Cleide Adriane Signor Tirloni
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Rhanany Alan Calloi Palozi
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Maysa Isernhagen Schaedler
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Lucas Pires Guarnier
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Aniely Oliveira Silva
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Valter Paes de Almeida
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Jane Manfron Budel
- Programa de Pós-Graduação em Ciências Farmacêuticas, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR, Brazil
| | - Roosevelt Isaias Carvalho Souza
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Ariany Carvalho Dos Santos
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil
| | - Vanessa Samúdio Dos Santos
- Laboratório de Produtos Naturais e Espectrometria de Massas (LaPNEM), Faculdade de Ciências Farmacêuticas, Alimentos e Nutrição (FACFAN), Universidade Federal do Mato Grosso do Sul, Campo Grande, MS, Brazil
| | - Denise Brentan Silva
- Laboratório de Produtos Naturais e Espectrometria de Massas (LaPNEM), Faculdade de Ciências Farmacêuticas, Alimentos e Nutrição (FACFAN), Universidade Federal do Mato Grosso do Sul, Campo Grande, MS, Brazil
| | - Paulo Roberto Dalsenter
- Laboratório de Toxicologia Reprodutiva, Universidade Federal do Paraná, Curitiba, PR, Brazil
| | - Arquimedes Gasparotto Junior
- Laboratório de Eletrofisiologia e Farmacologia Cardiovascular, Faculdade de Ciências da Saúde, Universidade Federal da Grande Dourados, Dourados, MS, Brazil.
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Brennan LJ, Goulopoulou S, Bourque SL. Prenatal therapeutics and programming of cardiovascular function. Pharmacol Res 2018; 139:261-272. [PMID: 30458216 DOI: 10.1016/j.phrs.2018.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 01/08/2023]
Abstract
Cardiovascular diseases (CVD) are a leading cause of mortality worldwide. Despite recognizing the importance of risk factors in dictating CVD susceptibility and onset, patient treatment remains a challenging endeavor. Increasingly, the benefits of prevention and mitigation of risk factors earlier in life are being acknowledged. The developmental origins of health and disease posits that insults during specific periods of development can influence long-term health outcomes; this occurs because the developing organism is highly plastic, and hence vulnerable to environmental perturbations. By extension, targeted therapeutics instituted during critical periods of development may confer long-term protection, and thus reduce the risk of CVD in later life. This review provides a brief overview of models of developmental programming, and then discusses the impact of perinatal therapeutic interventions on long-term cardiovascular function in the offspring. The discussion focuses on bioactive food components, as well as pharmacological agents currently approved for use in pregnancy; in short, those agents most likely to be used in pregnancy and early childhood.
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Affiliation(s)
- Lesley J Brennan
- Department of Anesthesiology & Pain Medicine, Pharmacology, and Pediatrics, Women and Children's Health Research Institute, University of Alberta, Canada.
| | - Styliani Goulopoulou
- Department of Physiology and Anatomy, University of North Texas Health Science Center, United States.
| | - Stephane L Bourque
- Department of Anesthesiology & Pain Medicine, Pharmacology, and Pediatrics, Women and Children's Health Research Institute, University of Alberta, Canada.
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65
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Craigie E, Menzies RI, Larsen CK, Jacquillet G, Carrel M, Wildman SS, Loffing J, Leipziger J, Shirley DG, Bailey MA, Unwin RJ. The renal and blood pressure response to low sodium diet in P2X4 receptor knockout mice. Physiol Rep 2018; 6:e13899. [PMID: 30350402 PMCID: PMC6198136 DOI: 10.14814/phy2.13899] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 09/25/2018] [Accepted: 09/27/2018] [Indexed: 01/02/2023] Open
Abstract
In the kidney, purinergic (P2) receptor-mediated ATP signaling has been shown to be an important local regulator of epithelial sodium transport. Appropriate sodium regulation is crucial for blood pressure (BP) control and disturbances in sodium balance can lead to hypo- or hypertension. Links have already been established between P2 receptor signaling and the development of hypertension, attributed mainly to vascular and/or inflammatory effects. A transgenic mouse model with deletion of the P2X4 receptor (P2X4-/- ) is known to have hypertension, which is thought to reflect endothelial dysfunction and impaired nitric oxide (NO) release. However, renal function in this model has not been characterized; moreover, studies in vitro have shown that the P2X4 receptor can regulate renal epithelial Na+ channel (ENaC) activity. Therefore, in the present study we investigated renal function and sodium handling in P2X4-/- mice, focusing on ENaC-mediated Na+ reabsorption. We confirmed an elevated BP in P2X4-/- mice compared with wild-type mice, but found that ENaC-mediated Na+ reabsorption is no different from wild-type and does not contribute to the raised BP observed in the knockout. However, when P2X4-/- mice were placed on a low sodium diet, BP normalized. Plasma aldosterone concentration tended to increase according to sodium restriction status in both genotypes; in contrast to wild-types, P2X4-/- mice did not show an increase in functional ENaC activity. Thus, although the increased BP in P2X4-/- mice has been attributed to endothelial dysfunction and impaired NO release, there is also a sodium-sensitive component.
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Affiliation(s)
- Eilidh Craigie
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Robert I. Menzies
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Casper K. Larsen
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - Grégory Jacquillet
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Monique Carrel
- Institue for AnatomyUniversity of ZürichZürichSwitzerland
| | - Scott S. Wildman
- Urinary System Physiology UnitMedway School of PharmacyUniversity of KentKentUnited Kingdom
| | | | - Jens Leipziger
- Department of Biomedicine, PhysiologyAarhus UniversityAarhus CDenmark
| | - David G. Shirley
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
| | - Matthew A. Bailey
- British Heart Foundation Centre for Cardiovascular ScienceUniversity of EdinburghEdinburghUnited Kingdom
| | - Robert J. Unwin
- Centre for NephrologyUniversity College London Medical SchoolLondonUnited Kingdom
- CVRM iMEDAstraZeneca GothenburgGothenburgSweden
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66
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Taylor LE, Gillis EE, Musall JB, Baban B, Sullivan JC. High-fat diet-induced hypertension is associated with a proinflammatory T cell profile in male and female Dahl salt-sensitive rats. Am J Physiol Heart Circ Physiol 2018; 315:H1713-H1723. [PMID: 30239234 PMCID: PMC6336972 DOI: 10.1152/ajpheart.00389.2018] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Evidence supports a sex difference in the impact of a high-fat diet (HFD) on cardiovascular outcomes, with male experimental animals exhibiting greater increases in blood pressure (BP) than female experimental animals. The immune system has been implicated in HFD-induced increases in BP, and there is a sex difference in T-cell activation in hypertension. The goal of this study was to determine the impact of HFD on BP and aortic and renal T cell profiles in male and female Dahl salt-sensitive (DSS) rats. We hypothesized that male DSS rats would have greater increases in BP and T cell infiltration in response to a HFD compared with female DSS rats. BP was measured by tail-cuff plethysmography, and aortic and renal T cells were assessed by flow cytometric analysis in male and female DSS rats on a normal-fat diet (NFD) or HFD from 12 to 16 wk of age. Four weeks of HFD increased BP in male and female DSS rats to a similar degree. Increases in BP were accompanied by increased percentages of CD4+ T cells and T helper (Th)17 cells in both sexes, although male rats had more proinflammatory T cells. Percentages of renal CD3+ and CD4+ T cells as well as Th17 cells were increased in both sexes by the HFD, although the increase in CD3+ T cells was greater in male rats. HFD also decreased the percentage of aortic and renal regulatory T cells in both sexes, although female rats maintained more regulatory T cells than male rats regardless of diet. In conclusion, both male and female DSS rats exhibit BP sensitivity to a HFD; however, the mechanisms mediating HFD-induced increases in BP may be distinct as male rats exhibit greater increases in the percentage of proinflammatory T cells than female rats. NEW & NOTEWORTHY Our study demonstrates that male and female Dahl salt-sensitive rats exhibit similar increases in blood pressure to a high-fat diet and an increase in aortic and renal T cells. These results are in contrast to studies showing that female rats remain normotensive and/or upregulate regulatory T cells in response to hypertensive stimuli compared with male rats. Our data suggest that a 4-wk high-fat diet has sex-specific effects on the T cell profile in Dahl salt-sensitive rats.
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Affiliation(s)
- Lia E Taylor
- Department of Physiology, Augusta University , Augusta, Georgia
| | - Ellen E Gillis
- Department of Physiology, Augusta University , Augusta, Georgia
| | | | - Babak Baban
- Department of Oral Biology, Augusta University , Augusta, Georgia
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Dietary Fructose Increases the Sensitivity of Proximal Tubules to Angiotensin II in Rats Fed High-Salt Diets. Nutrients 2018; 10:nu10091244. [PMID: 30200571 PMCID: PMC6164674 DOI: 10.3390/nu10091244] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 09/04/2018] [Accepted: 09/04/2018] [Indexed: 12/16/2022] Open
Abstract
Dietary fructose causes salt-sensitive hypertension. Proximal tubules (PTs) reabsorb 70% of the filtered NaCl. Angiotensin II (Ang II), atrial natriuretic peptide (ANP) and norepinephrine (NE) regulate this process. Although Ang II signaling blockade ameliorates fructose-induced salt-sensitive hypertension, basal PT Na⁺ reabsorption and its sensitivity to the aforementioned factors have not been studied in this model. We hypothesized consuming fructose with a high-salt diet selectively enhances the sensitivity of PT transport to Ang II. We investigated the effects of Ang II, ANP and NE on PT Na reabsorption in rats fed a high-salt diet drinking tap water (HS) or 20% fructose (HS-FRU). Oxygen consumption (QO₂) was used as a measure of all ATP-dependent transport processes. Na⁺/K⁺-ATPase and Na⁺/H⁺-exchange (NHE) activities were studied because they represent primary apical and basolateral transporters in this segment. The effect of 10-12 mol/L Ang II in QO₂ by PTs from HS-FRU was larger than HS (p < 0.02; n = 7). In PTs from HS-FRU 10-12 mol/L Ang II stimulated NHE activity by 2.6 ± 0.7 arbitrary fluorescence units/s (p < 0.01; n = 5) but not in those from HS. The stimulatory effect of Ang II on PT Na⁺/K⁺-ATPase activity was not affected by HS-FRU. Responses of QO₂ and NHE activity to ANP did not differ between groups. The response of QO₂ to NE was unaltered by HS-FRU. We concluded that the sensitivity of PT Na⁺ reabsorption specifically to Ang II is enhanced by HS-FRU. This maintains high rates of transport even in the presence of low concentrations of the peptide, and likely contributes to the hypertension.
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Ivy JR, Evans LC, Moorhouse R, Richardson RV, Al-Dujaili EAS, Flatman PW, Kenyon CJ, Chapman KE, Bailey MA. Renal and Blood Pressure Response to a High-Salt Diet in Mice With Reduced Global Expression of the Glucocorticoid Receptor. Front Physiol 2018; 9:848. [PMID: 30038578 PMCID: PMC6046455 DOI: 10.3389/fphys.2018.00848] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/14/2018] [Indexed: 01/02/2023] Open
Abstract
Salt-sensitive hypertension is common in glucocorticoid excess. Glucocorticoid resistance also presents with hypercortisolemia and hypertension but the relationship between salt intake and blood pressure (BP) is not well defined. GRβgeo/+ mice have global glucocorticoid receptor (GR) haploinsufficiency and increased BP. Here we examined the effect of high salt diet on BP, salt excretion and renal blood flow in GRβgeo/+mice. Basal BP was ∼10 mmHg higher in male GRβgeo/+ mice than in GR+/+ littermates. This modest increase was amplified by ∼10 mmHg following a high-salt diet in GRβgeo/+ mice. High salt reduced urinary aldosterone excretion but increased renal mineralocorticoid receptor expression in both genotypes. Corticosterone, and to a lesser extent deoxycorticosterone, excretion was increased in GRβgeo/+ mice following a high-salt challenge, consistent with enhanced 24 h production. GR+/+ mice increased fractional sodium excretion and reduced renal vascular resistance during the high salt challenge, retaining neutral sodium balance. In contrast, sodium excretion and renal vascular resistance did not adapt to high salt in GRβgeo/+ mice, resulting in transient sodium retention and sustained hypertension. With high-salt diet, Slc12a3 and Scnn1a mRNAs were higher in GRβgeo/+ than controls, and this was reflected in an exaggerated natriuretic response to thiazide and benzamil, inhibitors of NCC and ENaC, respectively. Reduction in GR expression causes salt-sensitivity and an adaptive failure of the renal vasculature and tubule, most likely reflecting sustained mineralocorticoid receptor activation. This provides a mechanistic basis to understand the hypertension associated with loss-of-function polymorphisms in GR in the context of habitually high salt intake.
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Affiliation(s)
- Jessica R Ivy
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Louise C Evans
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Rebecca Moorhouse
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Rachel V Richardson
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Emad A S Al-Dujaili
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Peter W Flatman
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Christopher J Kenyon
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Karen E Chapman
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
| | - Matthew A Bailey
- University of Edinburgh/British Heart Foundation Centre for Cardiovascular Science, The Queen's Medical Research Institute, The University of Edinburgh Medical School, The University of Edinburgh, Edinburgh, United Kingdom
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Abstract
PURPOSE OF REVIEW Here, we review current concepts on hypertensive crisis (HTN-C) with a focus on epidemiology, causes, pathophysiology and prognosis. We also offer a practical approach to the management of HTN-C. RECENT FINDINGS HTN-C is characterized by a severe and abrupt increase in blood pressure (BP) with impending or progressive acute end-organ damage (EOD). HTN-C can be divided into hypertensive emergency (HTN-E) and hypertensive urgency (HTN-U) based on the presence or absence of acute EOD, respectively. Recent retrospective studies have demonstrated that emergency department (ED) referrals from an outpatient clinic or rapid BP-lowering strategies in the ED do not lead to improved outcomes in patients with HTN-U. SUMMARY HTN-C can be a de-novo manifestation or a complication of essential or secondary HTN. The presence of acute EOD is a major poor prognostic indicator in HTN-C. The main objectives of the management of HTN-C are distinction of HTN-E from HTN-U and appropriate risk stratification, prevention or regression of acute EOD due to severely elevated BP, prevention of recurrence of HTN-C with an effective long-term management plan and avoidance of rapid lowering of BP except in some special circumstances. The majority of patients with asymptomatic HTN-U can be safely managed in the outpatient setting without exposing them to the risks of aggressive BP lowering. However, patients with HTN-E require hospitalization, prompt treatment and close monitoring.
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Wiig H, Luft FC, Titze JM. The interstitium conducts extrarenal storage of sodium and represents a third compartment essential for extracellular volume and blood pressure homeostasis. Acta Physiol (Oxf) 2018; 222. [PMID: 29193764 DOI: 10.1111/apha.13006] [Citation(s) in RCA: 87] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Revised: 10/31/2017] [Accepted: 11/23/2017] [Indexed: 12/15/2022]
Abstract
The role of salt in the pathogenesis of arterial hypertension is not well understood. According to the current understanding, the central mechanism for blood pressure (BP) regulation relies on classical studies linking BP and Na+ balance, placing the kidney at the very centre of long-term BP regulation. To maintain BP homeostasis, the effective circulating fluid volume and thereby body Na+ content has to be maintained within very narrow limits. From recent work in humans and rats, the notion has emerged that Na+ could be stored somewhere in the body without commensurate water retention to buffer free extracellular Na+ and that previously unidentified extrarenal, tissue-specific regulatory mechanisms are operative regulating the release and storage of Na+ from a kidney-independent reservoir. Moreover, immune cells from the mononuclear phagocyte system not only function as local on-site sensors of interstitial electrolyte concentration, but also, together with lymphatics, act as systemic regulators of body fluid volume and BP. These studies have established new and unexpected targets in studies of BP control and thus the pathophysiology of hypertension: the interstitium/extracellular matrix of the skin, its inherent interstitial fluid and the lymphatic vasculature forming a vessel network in the interstitium. Aspects of the interstitium in relation to Na+ balance and hypertension are the focus of this review. Taken together, observations of salt storage in the skin to buffer free extracellular Na+ and macrophage modulation of the extracellular matrix and lymphatics suggest that electrolyte homeostasis in the body cannot be achieved by renal excretion alone, but also relies on extrarenal regulatory mechanisms.
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Affiliation(s)
- H. Wiig
- Department of Biomedicine; University of Bergen; Bergen Norway
| | - F. C. Luft
- Experimental and Clinical Research Center; Max-Delbrück Center for Molecular Medicine; Charité Medical Faculty; Berlin Germany
- Division of Clinical Pharmacology; Department of Medicine; Vanderbilt University School of Medicine; Nashville TN USA
| | - J. M. Titze
- Division of Clinical Pharmacology; Department of Medicine; Vanderbilt University School of Medicine; Nashville TN USA
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71
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Colafella KMM, Denton KM. Sex-specific differences in hypertension and associated cardiovascular disease. Nat Rev Nephrol 2018; 14:185-201. [PMID: 29380817 DOI: 10.1038/nrneph.2017.189] [Citation(s) in RCA: 251] [Impact Index Per Article: 41.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Although intrinsic mechanisms that regulate arterial blood pressure (BP) are similar in men and women, marked variations exist at the molecular, cellular and tissue levels. These physiological disparities between the sexes likely contribute to differences in disease onset, susceptibility, prevalence and treatment responses. Key systems that are important in the development of hypertension and cardiovascular disease (CVD), including the sympathetic nervous system, the renin-angiotensin-aldosterone system and the immune system, are differentially activated in males and females. Biological age also contributes to sexual dimorphism, as premenopausal women experience a higher degree of cardioprotection than men of similar age. Furthermore, sex hormones such as oestrogen and testosterone as well as sex chromosome complement likely contribute to sex differences in BP and CVD. At the cellular level, differences in cell senescence pathways may contribute to increased longevity in women and may also limit organ damage caused by hypertension. In addition, many lifestyle and environmental factors - such as smoking, alcohol consumption and diet - may influence BP and CVD in a sex-specific manner. Evidence suggests that cardioprotection in women is lost under conditions of obesity and type 2 diabetes mellitus. Treatment strategies for hypertension and CVD that are tailored according to sex could lead to improved outcomes for affected patients.
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Affiliation(s)
- Katrina M Mirabito Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute, Monash University Wellington Road, Clayton, Victoria 3800, Australia.,Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Victoria 3800, Australia.,Division of Vascular Medicine and Pharmacology, Department of Internal Medicine, Erasmus MC, Wytemaweg 80, 3015 CN Rotterdam, Netherlands
| | - Kate M Denton
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute, Monash University Wellington Road, Clayton, Victoria 3800, Australia.,Department of Physiology, Monash University, 26 Innovation Walk, Clayton, Victoria 3800, Australia
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72
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Veiras LC, Girardi ACC, Curry J, Pei L, Ralph DL, Tran A, Castelo-Branco RC, Pastor-Soler N, Arranz CT, Yu ASL, McDonough AA. Sexual Dimorphic Pattern of Renal Transporters and Electrolyte Homeostasis. J Am Soc Nephrol 2017; 28:3504-3517. [PMID: 28774999 PMCID: PMC5698077 DOI: 10.1681/asn.2017030295] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Accepted: 06/20/2017] [Indexed: 12/30/2022] Open
Abstract
Compared with males, females have lower BP before age 60, blunted hypertensive response to angiotensin II, and a leftward shift in pressure natriuresis. This study tested the concept that this female advantage associates with a distinct sexual dimorphic pattern of transporters along the nephron. We applied quantitative immunoblotting to generate profiles of transporters, channels, claudins, and selected regulators in both sexes and assessed the physiologic consequences of the differences. In rats, females excreted a saline load more rapidly than males did. Compared with the proximal tubule of males, the proximal tubule of females had greater phosphorylation of Na+/H+ exchanger isoform 3 (NHE3), distribution of NHE3 at the base of the microvilli, and less abundant expression of Na+/Pi cotransporter 2, claudin-2, and aquaporin 1. These changes associated with less bicarbonate reabsorption and higher lithium clearance in females. The distal nephrons of females had a higher abundance of total and phosphorylated Na+/Cl- cotransporter (NCC), claudin-7, and cleaved forms of epithelial Na+ channel (ENaC) α and γ subunits, which associated with a lower baseline plasma K+ concentration. A K+-rich meal increased the urinary K+ concentration and decreased the level of renal phosphorylated NCC in females. Notably, we observed similar abundance profiles in female versus male C57BL/6 mice. These results define sexual dimorphic phenotypes along the nephron and suggest that lower proximal reabsorption in female rats expedites excretion of a saline load and enhances NCC and ENaC abundance and activation, which may facilitate K+ secretion and set plasma K+ at a lower level.
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Affiliation(s)
| | | | - Joshua Curry
- Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | - Lei Pei
- Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
| | | | - An Tran
- Department of Integrative Anatomical Sciences and
| | - Regiane C Castelo-Branco
- Department of Physiology and Biophysics, Biomedical Sciences Institute, University of São Paulo, São Paulo, Brazil; and
| | - Nuria Pastor-Soler
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine of University of Southern California, Los Angeles, California
| | - Cristina T Arranz
- University of Buenos Aires, National Council of Science and Technology, Buenos Aires, Argentina
| | - Alan S L Yu
- Kidney Institute, University of Kansas Medical Center, Kansas City, Kansas
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Abstract
The metabolic syndrome describes a clustering of risk factors—visceral obesity, dyslipidaemia, insulin resistance, and salt-sensitive hypertension—that increases mortality related to cardiovascular disease, type 2 diabetes, cancer, and non-alcoholic fatty liver disease. The prevalence of these concurrent comorbidities is ~ 25–30% worldwide, and metabolic syndrome therefore presents a significant global public health burden. Evidence from clinical and preclinical studies indicates that glucocorticoid excess is a key causal feature of metabolic syndrome. This is not increased systemic in circulating cortisol, rather increased bioavailability of active glucocorticoids within tissues. This review examines the role of covert glucocorticoid excess on the hypertension of the metabolic syndrome. Here, the role of the 11β-hydroxysteroid dehydrogenase enzymes, which exert intracrine and paracrine control over glucocorticoid signalling, is examined. 11βHSD1 amplifies glucocorticoid action in cells and contributes to hypertension through direct and indirect effects on the kidney and vasculature. The deactivation of glucocorticoid by 11βHSD2 controls ligand access to glucocorticoid and mineralocorticoid receptors: loss of function promotes salt retention and hypertension. As for hypertension in general, high blood pressure in the metabolic syndrome reflects a complex interaction between multiple systems. The clear association between high dietary salt, glucocorticoid production, and metabolic disorders has major relevance for human health and warrants systematic evaluation.
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Affiliation(s)
- Matthew A Bailey
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK.
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Solini A, Giannini L, Seghieri M, Vitolo E, Taddei S, Ghiadoni L, Bruno RM. Dapagliflozin acutely improves endothelial dysfunction, reduces aortic stiffness and renal resistive index in type 2 diabetic patients: a pilot study. Cardiovasc Diabetol 2017; 16:138. [PMID: 29061124 PMCID: PMC5654086 DOI: 10.1186/s12933-017-0621-8] [Citation(s) in RCA: 247] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/15/2017] [Indexed: 12/22/2022] Open
Abstract
Background Sodium-glucose cotransporter-2 inhibitors reduce blood pressure (BP) and renal and cardiovascular events in patients with type 2 diabetes through not fully elucidated mechanisms. Aim of this study was to investigate whether dapagliflozin is able to acutely modify systemic and renal vascular function, as well as putative mechanisms. Methods Neuro-hormonal and vascular variables, together with 24 h diuresis, urinary sodium, glucose, isoprostanes and free-water clearance were assessed before and after a 2-day treatment with dapagliflozin 10 mg QD in sixteen type 2 diabetic patients; data were compared with those obtained in ten patients treated with hydrochlorothiazide 12.5 mg QD. Brachial artery endothelium-dependent and independent vasodilation (by flow-mediated dilation) and pulse wave velocity were assessed. Renal resistive index was obtained at rest and after glyceryl trinitrate administration. Differences were analysed by repeated measures ANOVA, considering treatment as between factor and time as within factor; Bonferroni post hoc comparison test was also used. Results Dapagliflozin decreased systolic BP and induced an increase in 24 h diuresis to a similar extent of hydrochlorothiazide; 24 h urinary glucose and serum magnesium were also increased. 24 h urinary sodium and fasting blood glucose were unchanged. Oxidative stress was reduced, as by a decline in urinary isoprostanes. Flow-mediated dilation was significantly increased (2.8 ± 2.2 to 4.0 ± 2.1%, p < 0.05), and pulse-wave-velocity was reduced (10.1 ± 1.6 to 8.9 ± 1.6 m/s, p < 0.05), even after correction for mean BP. Renal resistive index was reduced (0.62 ± 0.04 to 0.59 ± 0.05, p < 0.05). These vascular modifications were not observed in hydrochlorothiazide-treated individuals. Conclusions An acute treatment with dapagliflozin significantly improves systemic endothelial function, arterial stiffness and renal resistive index; this effect is independent of changes in BP and occurs in the presence of stable natriuresis, suggesting a fast, direct beneficial effect on the vasculature, possibly mediated by oxidative stress reduction.
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Affiliation(s)
- Anna Solini
- Department of Surgical, Medical, Molecular and Critical Area Pathology, I-56126, Pisa, Italy.
| | - Livia Giannini
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Marta Seghieri
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Edoardo Vitolo
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Stefano Taddei
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Lorenzo Ghiadoni
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
| | - Rosa Maria Bruno
- Department of Clinical and Experimental Medicine, University of Pisa, Pisa, Italy
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Takahashi-Iwanaga H, Kimura S, Konno K, Watanabe M, Iwanaga T. Intrarenal signaling mediated by CCK plays a role in salt intake-induced natriuresis. Am J Physiol Renal Physiol 2017; 313:F20-F29. [DOI: 10.1152/ajprenal.00539.2016] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 03/07/2017] [Accepted: 03/10/2017] [Indexed: 11/22/2022] Open
Abstract
The natriuretic hormone CCK exhibits its gene transcripts in total kidney extracts. To test the possibility of CCK acting as an intrarenal mediator of sodium excretion, we examined mouse kidneys by 1) an in situ hybridization technique for CCK mRNA in animals fed a normal- or a high-sodium diet; 2) immuno-electron microscopy for the CCK peptide, 3) an in situ hybridization method and immunohistochemistry for the CCK-specific receptor CCKAR; 4) confocal image analysis of receptor-mediated Ca2+ responses in isolated renal tubules; and 5) metabolic cage experiments for the measurement of urinary sodium excretion in high-salt-fed mice either treated or untreated with the CCKAR antagonist lorglumide. Results showed the CCK gene to be expressed intensely in the inner medulla and moderately in the inner stripe of the outer medulla, with the expression in the latter being enhanced by high sodium intake. Immunoreactivity for the CCK peptide was localized to the rough endoplasmic reticulum of the medullary interstitial cells in corresponding renal regions, confirming it to be a secretory protein. Gene transcripts, protein products, and the functional activity for CCKAR were consistently localized to the late proximal tubule segments (S2 and S3) in the medullary rays, and the outer stripe of the outer medulla. Lorglumide significantly diminished natriuretic responses of mice to a dietary sodium load without altering the glomerular filtration rate. These findings suggest that the medullary interstitial cells respond to body fluid expansion by CCK release for feedback regulation of the late proximal tubular reabsorption.
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Affiliation(s)
| | - Shunsuke Kimura
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Kohtarou Konno
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Masahiko Watanabe
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
| | - Toshihiko Iwanaga
- Department of Anatomy, Hokkaido University Graduate School of Medicine, Sapporo, Japan
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Frame AA, Wainford RD. Renal sodium handling and sodium sensitivity. Kidney Res Clin Pract 2017; 36:117-131. [PMID: 28680820 PMCID: PMC5491159 DOI: 10.23876/j.krcp.2017.36.2.117] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/27/2016] [Indexed: 01/11/2023] Open
Abstract
The pathophysiology of hypertension, which affects over 1 billion individuals worldwide, involves the integration of the actions of multiple organ systems, including the kidney. The kidney, which governs sodium excretion via several mechanisms including pressure natriuresis and the actions of renal sodium transporters, is central to long term blood pressure regulation and the salt sensitivity of blood pressure. The impact of renal sodium handling and the salt sensitivity of blood pressure in health and hypertension is a critical public health issue owing to the excess of dietary salt consumed globally and the significant percentage of the global population exhibiting salt sensitivity. This review highlights recent advances that have provided new insight into the renal handling of sodium and the salt sensitivity of blood pressure, with a focus on genetic, inflammatory, dietary, sympathetic nervous system and oxidative stress mechanisms that influence renal sodium excretion. Increased understanding of the multiple integrated mechanisms that regulate the renal handling of sodium and the salt sensitivity of blood pressure has the potential to identify novel therapeutic targets and refine dietary guidelines designed to treat and prevent hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
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de Santana Aquino DF, Signor Tirloni CA, Tolouei Menegati SEL, Lima Cardoso CA, Heredia Vieira SC, Carmo Vieira MD, Simonet AM, Macías FA, Gasparotto A. Alibertia edulis (L.C. Rich.) A.C. Rich - A potent diuretic arising from Brazilian indigenous species. JOURNAL OF ETHNOPHARMACOLOGY 2017; 196:193-200. [PMID: 27988400 DOI: 10.1016/j.jep.2016.12.024] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Revised: 11/28/2016] [Accepted: 12/14/2016] [Indexed: 06/06/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Although Alibertia edulis (L.C. Rich.) A.C. Rich decoction is used in Brazilian folk medicine due to its possible antihypertensive effect, this species has never been critically investigated as a hypotensive drug. So, the aim of this study was to evaluate the possible hypotensive and antihypertensive effects of the oral administration of Alibertia edulis aqueous extract (AEAE) in normotensive and hypertensive rats, and evaluate its inter-relation with a possible diuretic activity. MATERIAL AND METHODS Different doses of AEAE (20, 65 and 200mg/kg) were tested on the mean arterial pressure (MAP) of normotensive Wistar rats and after induction of renovascular hypertension (two-kidney, one-clip Goldblatt model). In addition, the diuretic effects of AEAE were compared with hydrochlorothiazide (HCTZ) in an acute and repeated-dose treatment for 7 days. Volume, sodium, potassium, chloride, calcium contents, pH and density were estimated in urine samples collected after 8 or 24h. Plasma sodium, potassium, total protein, urea, creatinine, AST and ALT concentrations were measured in samples collected at the end of the experimental period (seventh day). Finally, the antioxidant activity of the AEAE was assessed using the DPPH radical scavenging and ferric ions reducing power assay. RESULTS The intraduodenal administration of the HCTZ and AEAE significantly reduced, in a dose-dependent manner, the MAP in both normotensive and hypertensive rats. Otherwise, the heart rate was not affected by any treatment. Acute and prolonged oral administration of AEAE (200mg/kg) and HCTZ caused a significant increase in volume and urinary concentrations of sodium, potassium and chloride. Moreover, urinary calcium concentration was significantly increased after administration of AEAE (200mg/kg). Finally, AEAE was able to present important in vitro antioxidant properties. CONCLUSION The results obtained have shown that AEAE presents potent diuretic activity and significant hypotensive and antihypertensive effect. In addition, this study may confirm part of the pharmacological activity popularly attributed to this species and opens perspective for the future use in various renal and cardiovascular diseases.
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Affiliation(s)
| | | | | | - Claudia Andrea Lima Cardoso
- Research Center in Biodiversity, Faculty of Chemistry, State University of Mato Grosso do Sul, Dourados, MS, Brazil
| | | | - Maria do Carmo Vieira
- Laboratory of Medicinal Plants, Faculty of Agrarian Sciences, Federal University of Grande Dourados, Dourados, MS, Brazil
| | - Ana María Simonet
- Department of Organic Chemistry, Faculty of Sciences, University of Cádiz, Cádiz, Spain
| | | | - Arquimedes Gasparotto
- Department of Organic Chemistry, Faculty of Sciences, University of Cádiz, Cádiz, Spain.
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78
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Chanavirut R, Tong-Un T, Jirakulsomchok D, Wyss JM, Roysommuti S. Abnormal autonomic nervous system function in rural Thai men: A potential contributor to their high risk of sudden unexplained nocturnal death syndrome. Int J Cardiol 2017; 226:87-92. [PMID: 27792993 DOI: 10.1016/j.ijcard.2016.10.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2016] [Revised: 09/30/2016] [Accepted: 10/03/2016] [Indexed: 02/08/2023]
Abstract
BACKGROUND Rural compared to urban Thai populations have a higher incidence of sudden unexplained nocturnal death syndrome (SUNDS). This study tests the hypothesis that compared to young urban Thai men, the young rural northeast Thai men display autonomic system dysfunction that may contribute to their relatively high risk to develop SUNDS. METHODS Forty-seven healthy second and third year students from Khon Kaen University (20-22years old) were divided into central, urban northeastern, and rural northeastern groups, based on the locality in which they had grown up and in which their parents had lived prior to their birth. RESULTS Body weight, body height, serum sodium, serum potassium, fasting blood sugar, glucose tolerance, resting mean arterial pressure, resting heart rate, ulnar nerve conduction velocity, and sympathetic and parasympathetic nervous system activity were not significantly different among the three groups. In contrast, compared to urban northeasterners and central Thais, rural northeasterners displayed low sympathetic and high parasympathetic responses to cold stress and oral saline load; however, baroreflex sensitivity and the autonomic nervous system responses to upright tilt were not significantly different among the three groups. In addition, respiratory rates at rest and in response to upright tilt, cold stress, and oral saline load were not significantly different among the three groups. CONCLUSIONS These data indicate that compared to central or urban, individuals from rural origin display decreased sympathetic and increased parasympathetic responses to stresses. These altered responses could predispose the individuals to inappropriate autonomic control during the stresses, including those resulting in SUNDS.
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Affiliation(s)
- Raoyrin Chanavirut
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand; Department of Physical Therapy, Faculty of Associated Medical Sciences, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Terdthai Tong-Un
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Dusit Jirakulsomchok
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand
| | - J Michael Wyss
- Department of Cell, Developmental and Integrative Biology, School of Medicine, University of Alabama at Birmingham, AL 35294, USA
| | - Sanya Roysommuti
- Department of Physiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
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79
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Bie P, Evans RG. Normotension, hypertension and body fluid regulation: brain and kidney. Acta Physiol (Oxf) 2017; 219:288-304. [PMID: 27214656 DOI: 10.1111/apha.12718] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2015] [Revised: 01/13/2016] [Accepted: 05/17/2016] [Indexed: 01/11/2023]
Abstract
The fraction of hypertensive patients with essential hypertension (EH) is decreasing as the knowledge of mechanisms of secondary hypertension increases, but in most new cases of hypertension the pathophysiology remains unknown. Separate neurocentric and renocentric concepts of aetiology have prevailed without much interaction. In this regard, several questions regarding the relationships between body fluid and blood pressure regulation are pertinent. Are all forms of EH associated with sympathetic overdrive or a shift in the pressure-natriuresis curve? Is body fluid homoeostasis normally driven by the influence of arterial blood pressure directly on the kidney? Does plasma renin activity, driven by renal nerve activity and renal arterial pressure, provide a key to stratification of EH? Our review indicates that (i) a narrow definition of EH is useful; (ii) in EH, indices of cardiovascular sympathetic activity are elevated in about 50% of cases; (iii) in EH as in normal conditions, mediators other than arterial blood pressure are the major determinants of renal sodium excretion; (iv) chronic hypertension is always associated with a shift in the pressure-natriuresis curve, but this may be an epiphenomenon; (v) plasma renin levels are useful in the analysis of EH only after metabolic standardization and then determination of the renin function line (plasma renin as a function of sodium intake); and (vi) angiotensin II-mediated hypertension is not a model of EH. Recent studies of baroreceptors and renal nerves as well as sodium intake and renin secretion help bridge the gap between the neurocentric and renocentric concepts.
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Affiliation(s)
- P. Bie
- Department of Cardiovascular and Renal Research; Institute of Molecular Medicine; University of Southern Denmark; Odense Denmark
- Cardiovascular Disease Program; Biomedicine Discovery Institute and Department of Physiology; Monash University; Melbourne Vic. Australia
| | - R. G. Evans
- Cardiovascular Disease Program; Biomedicine Discovery Institute and Department of Physiology; Monash University; Melbourne Vic. Australia
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80
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Gurusinghe S, Tambay A, Sethna CB. Developmental Origins and Nephron Endowment in Hypertension. Front Pediatr 2017; 5:151. [PMID: 28706894 PMCID: PMC5489607 DOI: 10.3389/fped.2017.00151] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Accepted: 06/15/2017] [Indexed: 12/27/2022] Open
Abstract
Primary hypertension continues to be one of the main risk factors for cardiovascular disease worldwide. A stable intrauterine environment is critical for the future development and health of the fetus. The developing kidney has been found to be especially vulnerable during this time period, and epidemiological studies have demonstrated that an adverse in utero environment is associated with an increased risk of hypertension and chronic kidney disease. Macro- and micronutrient deficiencies as well as exposure to tobacco, alcohol, and certain medications during gestation have been shown to negatively impact nephrogenesis and reduce one's nephron number. In 1988, Brenner et al. put forth the controversial hypothesis that a reduced nephron complement is a risk factor for hypertension and chronic kidney disease in adulthood. Since then numerous animal and human studies have confirmed this relationship demonstrating that there is an inverse association between blood pressure and nephron number. As our understanding of the developmental programming of hypertension and other non-communicable diseases improves, more effective preventive health measures can be developed in the future.
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Affiliation(s)
- Shari Gurusinghe
- Department of Pediatrics, Division of Pediatric Nephrology, Cohen Children's Medical Center of New York, New York, NY, United States
| | - Anita Tambay
- Department of Pediatrics, Division of Pediatric Nephrology, Cohen Children's Medical Center of New York, New York, NY, United States
| | - Christine B Sethna
- Department of Pediatrics, Division of Pediatric Nephrology, Cohen Children's Medical Center of New York, New York, NY, United States
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81
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Nakagawa H, Mizuno Y, Harada E, Morikawa Y, Kuwahara K, Saito Y, Yasue H. Brain Natriuretic Peptide Counteracting the Renin-angiotensin-aldosterone System in Accelerated Malignant Hypertension. Am J Med Sci 2016; 352:534-539. [PMID: 27865304 DOI: 10.1016/j.amjms.2016.08.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Accepted: 08/31/2016] [Indexed: 10/21/2022]
Abstract
We describe 2 patients, a 52-year-old woman and a 57-year-old man, with rapidly progressive hypertension and marked elevation of brain natriuretic peptide who exhibited polyuria, natriuresis, hypokalemia, posterior reversible encephalopathy syndrome and left ventricular dysfunction together with retinopathy and nephropathy, which were attenuated in a short time span of 1-2 months with normalization of blood pressure after the antihypertensive treatment. The possible role of brain natriuretic peptide in the pathophysiology of accelerated malignant hypertension was discussed and a review of the literature was completed.
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Affiliation(s)
- Hitoshi Nakagawa
- Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto, Japan; First Department of Internal Medicine, Nara Medical University, Kashihara, Japan
| | - Yuji Mizuno
- Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto, Japan
| | - Eisaku Harada
- Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto, Japan
| | - Yoshinobu Morikawa
- Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto, Japan; First Department of Internal Medicine, Nara Medical University, Kashihara, Japan
| | - Koichiro Kuwahara
- Department of Cardiovascular Medicine, Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - Yoshihiko Saito
- First Department of Internal Medicine, Nara Medical University, Kashihara, Japan
| | - Hirofumi Yasue
- Division of Cardiovascular Medicine, Kumamoto Kinoh Hospital, Kumamoto Aging Research Institute, Kumamoto, Japan.
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82
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Menzies RI, Tam FW, Unwin RJ, Bailey MA. Purinergic signaling in kidney disease. Kidney Int 2016; 91:315-323. [PMID: 27780585 DOI: 10.1016/j.kint.2016.08.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 08/10/2016] [Accepted: 08/15/2016] [Indexed: 02/04/2023]
Abstract
Nucleotides are key subunits for nucleic acids and provide energy for intracellular metabolism. They can also be released from cells to act physiologically as extracellular messengers or pathologically as danger signals. Extracellular nucleotides stimulate membrane receptors in the P2 and P1 family. P2X are ATP-activated cation channels; P2Y and P1 are G-protein coupled receptors activated by ATP, ADP, UTP, and UDP in the case of P2 or adenosine for P1. Renal P2 receptors influence both vascular contractility and tubular function. Renal cells also express ectonucleotidases that rapidly hydrolyze extracellular nucleotides. These enzymes integrate this multireceptor purinergic-signaling complex by determining the nucleotide milieu to titrate receptor activation. Purinergic signaling also regulates immune cell function by modulating the synthesis and release of various cytokines such as IL1-β and IL-18 as part of inflammasome activation. Abnormal or excessive stimulation of this intricate paracrine system can be pro- or anti-inflammatory, and is also linked to necrosis and apoptosis. Kidney tissue injury causes a localized increase in ATP concentration, and sustained activation of P2 receptors can lead to renal glomerular, tubular, and vascular cell damage. Purinergic receptors also regulate the activity and proliferation of fibroblasts, promoting both inflammation and fibrosis in chronic disease. In this short review we summarize some of the recent findings related to purinergic signaling in the kidney. We focus predominantly on the P2X7 receptor, discussing why antagonists have so far disappointed in clinical trials and how advances in our understanding of purinergic signaling might help to reposition these compounds as potential treatments for renal disease.
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Affiliation(s)
- Robert I Menzies
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
| | - Frederick W Tam
- Imperial College Renal and Transplant Centre, Department of Medicine, Imperial College London, UK
| | - Robert J Unwin
- Cardiovascular and Metabolic Diseases Biotech Unit, AstraZeneca Gothenburg, Sweden; UCL Centre for Nephrology, University College London, London, UK.
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, Scotland, UK
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83
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Mansley MK, Ivy JR, Bailey MA. ISN Forefronts Symposium 2015: The Evolution of Hypertension-Old Genes, New Concepts. Kidney Int Rep 2016; 1:197-203. [PMID: 27722209 PMCID: PMC5044930 DOI: 10.1016/j.ekir.2016.08.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 07/26/2016] [Accepted: 08/02/2016] [Indexed: 12/17/2022] Open
Abstract
Hypertension is known as the “silent killer,” driving the global public health burden of cardiovascular and renal disease. Blood pressure homeostasis is intimately associated with sodium balance and the distribution of sodium between fluid compartments and within tissues. On a population level, most societies consume 10 times more salt that the 0.5 g required by physiological need. This high salt intake is strongly linked to hypertension and to the World Health Organization targeting a ∼30% relative reduction in mean population salt intake to arrest the global mortality due to cardiovascular disease. But how does a habitually high-salt diet cause blood pressure to rise? In this focused review, we discuss 2 “evolutionary medicine” concepts, presented at the ISN Forefront Meeting “Immunomodulation of Cardio-renal Function.” We first examine how ancestral variants in genes that conferred a selection advantage during early human development are now maladaptive. We then discuss the conservation of “renal” sodium transport processes across multiple organ systems, including the brain. These systems influence sodium appetite and can exert an often-overlooked effect on long-term blood pressure control.
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Affiliation(s)
- Morag K Mansley
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Jessica R Ivy
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- The British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
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84
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Ruan XZ, Guan Y, Liu ZH, Eckardt KU, Unwin R. Summary of ISN Forefronts Symposium 2015: ‘Immunomodulation of Cardio-Renal Function’. Kidney Int Rep 2016. [PMCID: PMC5678622 DOI: 10.1016/j.ekir.2016.06.007] [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] [Indexed: 11/22/2022] Open
Abstract
The International Society of Nephrology Forefronts Symposium Immunomodulation of Cardio-Renal Function took place October 22 to 25, 2015, in Shenzhen, China. The program covered basic and clinical aspects of cardio-renal pathophysiology and immunity. Leading scientists from different and related disciplines of clinical and basic research described and reviewed recent discoveries, and discussed emerging topics under the headings “Immunity and Renal Pathophysiology”; “Autoimmunity and the Inflammasome”; “Immunity and the Gut Microbiome”; “Immuno-Metabolism”; “Immunogenetics, Transcriptomics and Epigenetics; “Immunity and Hypertension”; and “Immunity, Fibrosis, and Kidney Disease.”
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85
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Frise MC, Dorrington KL. Age, sex and arterial pressure: the kidney is essential. Exp Physiol 2016; 101:448. [PMID: 27511127 DOI: 10.1113/ep085477] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Matthew C Frise
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford, OX1 3PT, UK
| | - Keith L Dorrington
- University of Oxford, Department of Physiology, Anatomy & Genetics, Parks Road, Oxford, OX1 3PT, UK
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86
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Digne-Malcolm H, Frise MC, Dorrington KL. How Do Antihypertensive Drugs Work? Insights from Studies of the Renal Regulation of Arterial Blood Pressure. Front Physiol 2016; 7:320. [PMID: 27524972 PMCID: PMC4965470 DOI: 10.3389/fphys.2016.00320] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Accepted: 07/13/2016] [Indexed: 11/13/2022] Open
Abstract
Though antihypertensive drugs have been in use for many decades, the mechanisms by which they act chronically to reduce blood pressure remain unclear. Over long periods, mean arterial blood pressure must match the perfusion pressure necessary for the kidney to achieve its role in eliminating the daily intake of salt and water. It follows that the kidney is the most likely target for the action of most effective antihypertensive agents used chronically in clinical practice today. Here we review the long-term renal actions of antihypertensive agents in human studies and find three different mechanisms of action for the drugs investigated. (i) Selective vasodilatation of the renal afferent arteriole (prazosin, indoramin, clonidine, moxonidine, α-methyldopa, some Ca(++)-channel blockers, angiotensin-receptor blockers, atenolol, metoprolol, bisoprolol, labetolol, hydrochlorothiazide, and furosemide). (ii) Inhibition of tubular solute reabsorption (propranolol, nadolol, oxprenolol, and indapamide). (iii) A combination of these first two mechanisms (amlodipine, nifedipine and ACE-inhibitors). These findings provide insights into the actions of antihypertensive drugs, and challenge misconceptions about the mechanisms underlying the therapeutic efficacy of many of the agents.
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Affiliation(s)
| | - Matthew C. Frise
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
| | - Keith L. Dorrington
- Department of Physiology, Anatomy and Genetics, University of OxfordOxford, UK
- Nuffield Department of Anaesthetics, John Radcliffe HospitalOxford, UK
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87
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Morris RC, Schmidlin O, Sebastian A, Tanaka M, Kurtz TW. Vasodysfunction That Involves Renal Vasodysfunction, Not Abnormally Increased Renal Retention of Sodium, Accounts for the Initiation of Salt-Induced Hypertension. Circulation 2016; 133:881-93. [PMID: 26927006 DOI: 10.1161/circulationaha.115.017923] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- R Curtis Morris
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco.
| | - Olga Schmidlin
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Anthony Sebastian
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Masae Tanaka
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco
| | - Theodore W Kurtz
- From the Departments of Medicine (R.C.M., O.S., A.S., M.T.) and Laboratory Medicine (T.W.K.), University of California, San Francisco.
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Honig A, Eliahou R, Pikkel YY, Leker RR. Drops in Barometric Pressure Are Associated with Deep Intracerebral Hemorrhage. J Stroke Cerebrovasc Dis 2016; 25:872-6. [DOI: 10.1016/j.jstrokecerebrovasdis.2015.11.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 10/19/2015] [Accepted: 11/22/2015] [Indexed: 01/17/2023] Open
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Ivy JR, Oosthuyzen W, Peltz TS, Howarth AR, Hunter RW, Dhaun N, Al-Dujaili EAS, Webb DJ, Dear JW, Flatman PW, Bailey MA. Glucocorticoids Induce Nondipping Blood Pressure by Activating the Thiazide-Sensitive Cotransporter. Hypertension 2016; 67:1029-37. [PMID: 26953322 PMCID: PMC4905621 DOI: 10.1161/hypertensionaha.115.06977] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Accepted: 02/08/2016] [Indexed: 12/04/2022]
Abstract
Supplemental Digital Content is available in the text. Blood pressure (BP) normally dips during sleep, and nondipping increases cardiovascular risk. Hydrochlorothiazide restores the dipping BP profile in nondipping patients, suggesting that the NaCl cotransporter, NCC, is an important determinant of daily BP variation. NCC activity in cells is regulated by the circadian transcription factor per1. In vivo, circadian genes are entrained via the hypothalamic–pituitary–adrenal axis. Here, we test whether abnormalities in the day:night variation of circulating glucocorticoid influence NCC activity and BP control. C57BL6/J mice were culled at the peak (1:00 AM) and trough (1:00 PM) of BP. We found no day:night variation in NCC mRNA or protein but NCC phosphorylation on threonine53 (pNCC), required for NCC activation, was higher when mice were awake, as was excretion of NCC in urinary exosomes. Peak NCC activity correlated with peak expression of per2 and bmal1 (clock genes) and sgk1 and tsc22d3 (glucocorticoid-responsive kinases). Adrenalectomy reduced NCC abundance and blunted the daily variation in pNCC levels without affecting variation in clock gene transcription. Chronic corticosterone infusion increased bmal1, per1, sgk1, and tsc22d3 expression during the inactive phase. Inactive phase pNCC was also elevated by corticosterone, and a nondipping BP profile was induced. Hydrochlorothiazide restored rhythmicity of BP in corticosterone-treated mice without affecting BP in controls. Glucocorticoids influence the day:night variation in NCC activity via kinases that control phosphorylation. Abnormal glucocorticoid rhythms impair NCC and induce nondipping. Night-time dosing of thiazides may be particularly beneficial in patients with modest glucocorticoid excess.
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Affiliation(s)
- Jessica R Ivy
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Wilna Oosthuyzen
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Theresa S Peltz
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Amelia R Howarth
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Robert W Hunter
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Neeraj Dhaun
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Emad A S Al-Dujaili
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - David J Webb
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - James W Dear
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Peter W Flatman
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.)
| | - Matthew A Bailey
- From the The British Heart Foundation Centre for Cardiovascular Science (J.R.I., W.O., T.S.P., A.R.H., R.W.H., N.D., D.J.W., J.W.D., M.A.B.) and The Centre for Integrative Physiology (P.W.F.), The University of Edinburgh, Edinburgh, United Kingdom; and Dietetics, Nutrition, and Biological Sciences Department, Queen Margaret University, Musselburgh, United Kingdom (E.A.S.A.-D.).
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Evans LC, Ivy JR, Wyrwoll C, McNairn JA, Menzies RI, Christensen TH, Al-Dujaili EAS, Kenyon CJ, Mullins JJ, Seckl JR, Holmes MC, Bailey MA. Conditional Deletion of Hsd11b2 in the Brain Causes Salt Appetite and Hypertension. Circulation 2016; 133:1360-70. [PMID: 26951843 PMCID: PMC4819772 DOI: 10.1161/circulationaha.115.019341] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2015] [Accepted: 02/12/2016] [Indexed: 11/30/2022]
Abstract
Supplemental Digital Content is available in the text. Background— The hypertensive syndrome of Apparent Mineralocorticoid Excess is caused by loss-of-function mutations in the gene encoding 11β-hydroxysteroid dehydrogenase type 2 (11βHSD2), allowing inappropriate activation of the mineralocorticoid receptor by endogenous glucocorticoid. Hypertension is attributed to sodium retention in the distal nephron, but 11βHSD2 is also expressed in the brain. However, the central contribution to Apparent Mineralocorticoid Excess and other hypertensive states is often overlooked and is unresolved. We therefore used a Cre-Lox strategy to generate 11βHSD2 brain-specific knockout (Hsd11b2.BKO) mice, measuring blood pressure and salt appetite in adults. Methods and Results— Basal blood pressure, electrolytes, and circulating corticosteroids were unaffected in Hsd11b2.BKO mice. When offered saline to drink, Hsd11b2.BKO mice consumed 3 times more sodium than controls and became hypertensive. Salt appetite was inhibited by spironolactone. Control mice fed the same daily sodium intake remained normotensive, showing the intrinsic salt resistance of the background strain. Dexamethasone suppressed endogenous glucocorticoid and abolished the salt-induced blood pressure differential between genotypes. Salt sensitivity in Hsd11b2.BKO mice was not caused by impaired renal sodium excretion or volume expansion; pressor responses to phenylephrine were enhanced and baroreflexes impaired in these animals. Conclusions— Reduced 11βHSD2 activity in the brain does not intrinsically cause hypertension, but it promotes a hunger for salt and a transition from salt resistance to salt sensitivity. Our data suggest that 11βHSD2-positive neurons integrate salt appetite and the blood pressure response to dietary sodium through a mineralocorticoid receptor–dependent pathway. Therefore, central mineralocorticoid receptor antagonism could increase compliance to low-sodium regimens and help blood pressure management in cardiovascular disease.
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Affiliation(s)
- Louise C Evans
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jessica R Ivy
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Caitlin Wyrwoll
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Julie A McNairn
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Robert I Menzies
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Thorbjørn H Christensen
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Emad A S Al-Dujaili
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Christopher J Kenyon
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - John J Mullins
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Jonathan R Seckl
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Megan C Holmes
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense
| | - Matthew A Bailey
- From British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom (L.C.E., J.R.I., C.W., J.A.M., R.I.M., T.H.C., C.J.K., J.J.M., J.R.S., M.C.H., M.A.B.); and Dietetics, Nutrition and Biological Sciences Department, Queen Margaret University, Edinburgh, United Kingdom (E.A.S.Al-D.). The current address for Dr Evans is Department of Physiology, Cardiovascular Center, Medical College of Wisconsin, Milwaukee; the current address for Dr Wyrwoll is School of Anatomy, Physiology & Human Biology, The University of Western Australia, Crawley, Australia; and the current address for Dr Christensen is Department of Cardiovascular and Renal Research, University of Southern Denmark, Odense.
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92
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Affiliation(s)
- Rhian M Touyz
- From the Institute of Cardiovascular and Medical Sciences, BHF Glasgow Cardiovascular Research Centre, University of Glasgow, Glasgow, United Kingdom.
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93
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Affiliation(s)
- Louise Robson
- Department of Biomedical Science, University of Sheffield, Western Bank, Sheffield, S10 2TN, UK
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94
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Menzies RI, Howarth AR, Unwin RJ, Tam FWK, Mullins JJ, Bailey MA. Inhibition of the purinergic P2X7 receptor improves renal perfusion in angiotensin-II-infused rats. Kidney Int 2015; 88:1079-87. [PMID: 26108066 DOI: 10.1038/ki.2015.182] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 04/19/2015] [Accepted: 04/23/2015] [Indexed: 12/14/2022]
Abstract
Chronic activation of the renin-angiotensin system promotes hypertension, renal microvascular dysfunction, tissue hypoxia, and inflammation. Despite similar hypertension, an injurious response to excess angiotensin II is greater in F344 than in Lewis rats; the latter displaying renoprotection. Here we studied whether p2rx7, encoding the P2X7 receptor (P2X7R), is a candidate gene for the differential susceptibility to vascular dysfunction under high angiotensin II tone. A 14-day infusion of angiotensin II into F344 rats increased blood pressure by about 15 mm Hg without inducing fibrosis or albuminuria. In vivo pressure natriuresis was suppressed, medullary perfusion reduced by half, and the corticomedullary oxygenation gradient disrupted. Selective P2X7R antagonism restored pressure natriuresis, promoting a significant leftward shift in the intercept and increasing the slope. Sodium excretion was increased sixfold and blood pressure normalized. The specific P2X7R antagonist AZ11657312 increased renal medullary perfusion, but only in angiotensin II-treated rats. Tissue oxygenation was improved by P2X7R blockade, particularly in poorly oxygenated regions of the kidney. Thus, activation of P2X7R induces microvascular dysfunction and regional hypoxia when angiotensin II is elevated and these effects may contribute to progression of renal injury induced by chronic angiotensin II.
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Affiliation(s)
- Robert I Menzies
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK.,Institute of Genetics and Molecular Medicine, The University of Edinburgh, Edinburgh, UK
| | - Amelia R Howarth
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Robert J Unwin
- Cardiovascular and Metabolic Diseases (iMed CVMD) R&D, AstraZeneca, Mölndal, Sweden.,UCL Centre for Nephrology, University College London, London, UK
| | - Frederick W K Tam
- Imperial College Renal and Transplant Centre, Department of Medicine, Imperial College London, London, UK
| | - John J Mullins
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
| | - Matthew A Bailey
- University/British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, Edinburgh, UK
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95
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Howarth AR, Conway BR, Bailey MA. Vascular and inflammatory actions of P2X receptors in renal injury. Auton Neurosci 2015; 191:135-40. [PMID: 25998687 DOI: 10.1016/j.autneu.2015.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
P2 purinergic receptors are activated by extracellular ATP and subserve a plethora of roles in the body, including metabolism, inflammation and neuronal signalling. This review focuses on renal purinergic receptors and how different roles that they play may contribute to renal dysfunction and the progression of chronic kidney disease. Numerous studies have linked P2 receptors, particularly the P2X4R and P2X7R subtypes, to kidney injury and damage. However, the mechanisms underlying this association are not fully defined. Several studies show that activation of P2X4R and particularly P2X7R can have a pro-inflammatory effect, causing or exacerbating damage to renal tissue. However, clinical trials aiming to utilise P2X7R antagonists to treat inflammatory disease have been unsuccessful, and it is possible that other mechanisms besides inflammation tie P2X7R activation to disease progression. In this context, purinergic signalling is also involved in the control of vascular tone and our recent studies suggest that activation of P2X4R/P2X7R causes renal vascular dysfunction and contributes to chronic kidney disease. This brief review aims to summarise the complementary inflammatory and vascular roles of P2X receptors in the kidney, with emphasis on the subtypes P2X4R and P27XR, and how each contributes to and presents therapeutic targets in the progression of chronic kidney disease.
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Affiliation(s)
- Amelia R Howarth
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom
| | - Bryan R Conway
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom
| | - Matthew A Bailey
- British Heart Foundation Centre for Cardiovascular Science, The University of Edinburgh, United Kingdom.
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96
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Franco M, Bautista-Pérez R, Pérez-Méndez O. Purinergic receptors in tubulointerstitial inflammatory cells: a pathophysiological mechanism of salt-sensitive hypertension. Acta Physiol (Oxf) 2015; 214:75-87. [PMID: 25683649 DOI: 10.1111/apha.12471] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 10/28/2014] [Accepted: 02/09/2015] [Indexed: 12/24/2022]
Abstract
Recent studies have suggested that both the tubulointerstitial inflammatory cells and the activation of purinergic receptors integrate common mechanisms that result in salt-sensitive hypertension. The basis of this hypothesis is that renal endothelial cells release ATP in response to shear stress in the setting of hypertension. It has been demonstrated that the over-expression and activation of the P2X7, P2Y12 and P2X1 receptors favour the elevation of blood pressure induced by high-salt intake. In addition, the release of interleukins and inflammatory mediators in the tubulointerstitial area appears to be related to the activation of these receptors. Renal vasoconstriction and tubulointerstitial injury develop as a result, which increase sodium reabsorption by epithelial cells. Consistent with these effects, the reduction of tubulointerstitial inflammation caused by immunosuppressants, such as mycophenolate mofetil, prevents the development of salt-sensitive hypertension. Also, P2X7-receptor knockout mice develop minor renal injury when hypertension is induced via the administration of deoxycorticosterone acetate and a high-salt diet. In the setting of angiotensin II-induced hypertension, which is an early stage in the development of salt-sensitive hypertension, an acute blockade with the specific, non-selective P2 antagonist pyridoxalphosphate-6-azophenyl-2',4'-disulfonic acid prevented the renal vasoconstriction induced by angiotensin II. In addition, it normalized glomerular haemodynamics and restored sodium excretion to control values. These findings suggest that chronic administration of P2 purinergic antagonists may prevent the deleterious effects of purinergic receptors during the development of salt-sensitive hypertension.
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Affiliation(s)
- M. Franco
- Renal Physiopathology Laboratory; Department of Nephrology; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
| | - R. Bautista-Pérez
- Renal Physiopathology Laboratory; Department of Nephrology; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
- Molecular Biology Department; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
| | - O. Pérez-Méndez
- Molecular Biology Department; Instituto Nacional de Cardiología Ignacio Chávez; México City Mexico
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97
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Thieme K, Oliveira-Souza M. Renal hemodynamic and morphological changes after 7 and 28 days of leptin treatment: the participation of angiotensin II via the AT1 receptor. PLoS One 2015; 10:e0122265. [PMID: 25793389 PMCID: PMC4368722 DOI: 10.1371/journal.pone.0122265] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 02/17/2015] [Indexed: 01/13/2023] Open
Abstract
The role of hyperleptinemia in cardiovascular diseases is well known; however, in the renal tissue, the exact site of leptin’s action has not been established. This study was conducted to assess the effect of leptin treatment for 7 and 28 days on renal function and morphology and the participation of angiotensin II (Ang II), through its AT1 receptor. Rats were divided into four groups: sham, losartan (10 mg/kg/day, s.c.), leptin (0.5 mg/kg/day for the 7 days group and 0.25 mg/kg/day for the 28 days group) and leptin plus losartan. Plasma leptin, Ang II and endothelin 1 (ET-1) levels were measured using an enzymatic immuno assay. The systolic blood pressure (SBP) was evaluated using the tail-cuff method. The renal plasma flow (RPF) and the glomerular filtration rate (GFR) were determined by p-aminohippuric acid and inulin clearance, respectively. Urinary Na+ and K+ levels were also analyzed. Renal morphological analyses, desmin and ED-1 immunostaining were performed. Proteinuria was analyzed by silver staining. mRNA expression of renin-angiotensin system (RAS) components, TNF-α and collagen type III was analyzed by quantitative PCR. Our results showed that leptin treatment increased Ang II plasma levels and progressively increased the SBP, achieving a pre-hypertension state. Rats treated with leptin 7 days showed a normal RPF and GFR, but increased filtration fraction (FF) and natriuresis. However, rats treated with leptin for 28 showed a decrease in the RPF, an increase in the FF and no changes in the GFR or tubular function. Leptin treatment-induced renal injury was demonstrated by: glomerular hypertrophy, increased desmin staining, macrophage infiltration in the renal tissue, TNF-α and collagen type III mRNA expression and proteinuria. In conclusion, our study demonstrated the progressive renal morphological changes in experimental hyperleptinemia and the interaction between leptin and the RAS on these effects.
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Affiliation(s)
- Karina Thieme
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
- * E-mail:
| | - Maria Oliveira-Souza
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, Brazil
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Menzies RI, Unwin RJ, Bailey MA. Renal P2 receptors and hypertension. Acta Physiol (Oxf) 2015; 213:232-41. [PMID: 25345692 DOI: 10.1111/apha.12412] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 09/23/2014] [Accepted: 10/17/2014] [Indexed: 12/11/2022]
Abstract
The regulation of extracellular fluid volume is a key component of blood pressure homeostasis. Long-term blood pressure is stabilized by the acute pressure natriuresis response by which changes in renal perfusion pressure evoke corresponding changes in renal sodium excretion. A wealth of experimental evidence suggests that a defect in the pressure natriuresis response contributes to the development and maintenance of hypertension. The mechanisms underlying the relationship between renal perfusion pressure and sodium excretion are incompletely understood. Increased blood flow through the vasa recta increases renal interstitial hydrostatic pressure, thereby reducing the driving force for transepithelial sodium reabsorption. Paracrine signalling also contributes to the overall natriuretic response by inhibiting tubular sodium reabsorption in several nephron segments. In this brief review, we discuss the role of purinergic signalling in the renal control of blood pressure. ATP is released from renal tubule and vascular cells in response to increased flow and can activate P2 receptor subtypes expressed in both epithelial and vascular endothelial/smooth muscle cells. In concert, these effects integrate the vascular and tubular responses to increased perfusion pressure and targeting P2 receptors, particularly P2X7, may prove beneficial for treatment of hypertension.
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Affiliation(s)
- R. I. Menzies
- University/British Heart Foundation; Centre for Cardiovascular Science; The University of Edinburgh; Edinburgh UK
- MRC Institute for Genetics and Molecular Medicine; The University of Edinburgh; Edinburgh UK
| | - R. J. Unwin
- UCL Centre for Nephrology; University College London; London UK
| | - M. A. Bailey
- University/British Heart Foundation; Centre for Cardiovascular Science; The University of Edinburgh; Edinburgh UK
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