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Reckelhoff JF. Mechanisms of sex and gender differences in hypertension. J Hum Hypertens 2023; 37:596-601. [PMID: 36797338 DOI: 10.1038/s41371-023-00810-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 01/10/2023] [Accepted: 02/03/2023] [Indexed: 02/18/2023]
Abstract
The mechanisms that control blood pressure are multifaceted including the sympathetic nervous system and the renin-angiotensin system leading to vasoconstriction and sodium reabsorption that causes a shift in the pressure-natriuesis relationship to higher blood pressures. Sex steroids can affect these mechanisms either directly or indirectly, and the effects may be different depending on the sex of the individual. This review will discuss some of the major blood pressure-controlling mechanisms and how sex steroids may affect them and the need for future studies to better clarify the mechanisms responsible for sex and gender differences in blood pressure control. New mechanisms that are identified, along with what is already known, will provide better tools for treatment of hypertension in men and women of all ethnicities and decrease the risk of cardiovascular disease in the future.
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Affiliation(s)
- Jane F Reckelhoff
- Department of Cell and Molecular Biology, Women's Health Research Center, Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, MS, USA.
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2
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Li S, Phillips JK. Patient Selection for Renal Denervation in Hypertensive Patients: What Makes a Good Candidate? Vasc Health Risk Manag 2022; 18:375-386. [PMID: 35592729 PMCID: PMC9113553 DOI: 10.2147/vhrm.s270182] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Accepted: 04/22/2022] [Indexed: 01/03/2023] Open
Affiliation(s)
- Sheran Li
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
- Department of Emergency Medicine, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, Guangzhou, People’s Republic of China
- Correspondence: Sheran Li, Department of Emergency Medicine, Sun Yat-sen Memorial Hospital of Sun Yat-sen University, 107 West Yanjiang Road, Yuexiu District, Guangzhou, Guangdong Province, 510120, People’s Republic of China, Tel +86 20 81332723, Fax +86 20 8133 2650, Email
| | - Jacqueline K Phillips
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, Sydney, New South Wales, Australia
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3
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Sabbatini AR, Kararigas G. Estrogen-related mechanisms in sex differences of hypertension and target organ damage. Biol Sex Differ 2020; 11:31. [PMID: 32487164 PMCID: PMC7268741 DOI: 10.1186/s13293-020-00306-7] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 05/04/2020] [Indexed: 12/13/2022] Open
Abstract
Hypertension (HTN) is a primary risk factor for cardiovascular (CV) events, target organ damage (TOD), premature death and disability worldwide. The pathophysiology of HTN is complex and influenced by many factors including biological sex. Studies show that the prevalence of HTN is higher among adults aged 60 and over, highlighting the increase of HTN after menopause in women. Estrogen (E2) plays an important role in the development of systemic HTN and TOD, exerting several modulatory effects. The influence of E2 leads to alterations in mechanisms regulating the sympathetic nervous system, renin-angiotensin-aldosterone system, body mass, oxidative stress, endothelial function and salt sensitivity; all associated with a crucial inflammatory state and influenced by genetic factors, ultimately resulting in cardiac, vascular and renal damage in HTN. In the present article, we discuss the role of E2 in mechanisms accounting for the development of HTN and TOD in a sex-specific manner. The identification of targets with therapeutic potential would contribute to the development of more efficient treatments according to individual needs.
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Affiliation(s)
| | - Georgios Kararigas
- Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
- DZHK (German Centre for Cardiovascular Research), partner site Berlin, Berlin, Germany.
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4
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Edwards JM, Roy S, Tomcho JC, Schreckenberger ZJ, Chakraborty S, Bearss NR, Saha P, McCarthy CG, Vijay-Kumar M, Joe B, Wenceslau CF. Microbiota are critical for vascular physiology: Germ-free status weakens contractility and induces sex-specific vascular remodeling in mice. Vascul Pharmacol 2020; 125-126:106633. [PMID: 31843471 PMCID: PMC7036036 DOI: 10.1016/j.vph.2019.106633] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/25/2019] [Accepted: 12/10/2019] [Indexed: 12/11/2022]
Abstract
Commensal microbiota within a holobiont contribute to the overall health of the host via mutualistic symbiosis. Disturbances in such symbiosis is prominently correlated with a variety of diseases affecting the modern society of humans including cardiovascular diseases, which are the number one contributors to human mortality. Given that a hallmark of all cardiovascular diseases is changes in vascular function, we hypothesized that depleting microbiota from a holobiont would induce vascular dysfunction. To test this hypothesis, young mice of both sexes raised in germ-free conditions were examined vascular contractility and structure. Here we observed that male and female germ-free mice presented a decrease in contraction of resistance arteries. These changes were more pronounced in germ-free males than in germ-free females mice. Furthermore, there was a distinct change in vascular remodeling between males and females germ-free mice. Resistance arteries from male germ-free mice demonstrated increased vascular stiffness, as shown by the leftward shift in the stress-strain curve and inward hypotrophic remodeling, a characteristic of chronic reduction in blood flow. On the other hand, resistance arteries from germ-free female mice were similar in the stress-strain curves to that of conventionally raised mice, but were distinctly different and showed outward hypertrophic remodeling, a characteristic seen in aging. Interestingly, we observed that reactive oxygen species (ROS) generation from bone marrow derived neutrophils is blunted in female germ-free mice, but it is exacerbated in male germ-free mice. In conclusion, these observations indicate that commensal microbiota of a holobiont are central to maintain proper vascular function and structure homeostasis, especially in males.
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Affiliation(s)
- Jonnelle M Edwards
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Shaunak Roy
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Jeremy C Tomcho
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Zachary J Schreckenberger
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Saroj Chakraborty
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Nicole R Bearss
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Piu Saha
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Cameron G McCarthy
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Matam Vijay-Kumar
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Bina Joe
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA
| | - Camilla F Wenceslau
- Microbiome Consortium, Center for Hypertension and Precision Medicine, Department of Physiology and Pharmacology, University of Toledo College of Medicine & Life Sciences, Toledo, OH, USA.
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5
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Gong L, Jiang F, Zhang Z, Wang X, Li H, Kuang Y, Yang G. Catheter-Based Renal Denervation Attenuates Kidney Interstitial Fibrosis in a Canine Model of High-Fat Diet-Induced Hypertension. Kidney Blood Press Res 2019; 44:628-642. [PMID: 31291627 DOI: 10.1159/000500918] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Accepted: 05/12/2019] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND/AIMS Catheter-based renal denervation (RDN) has emerged as an innovative interventional approach for reducing blood pressure (BP), suppressing ventricular substrate remodeling, and attenuating heart failure, which suggests that it might reduce kidney fibrosis in a canine model of high-fat diet-induced hypertension. This study thus sought to assess whether RDN could reduce kidney fibrosis and halt the progression of renal impairment in a canine model of high-fat diet-induced hypertension. METHODS Thirty-two beagles were randomized into either the normal control group (normal diet, n = 10) or the hypertension group (high-fat diet, n = 22). After successful establishment of the model, the hypertension model group was randomized to either the RDN group (n = 9) or the sham-surgery group (n = 8). Renal artery angiography, BP, heart rate (HR), and blood and urine biochemistry results were assessed at 1, 3, and 6 months after surgery. Canines were sacrificed at 6 months after surgery. The extent of kidney interstitial fibrosis, transforming growth factor-beta 1, alpha-smooth muscle actin, connective tissue growth factor, and E-cadherin protein were measured. RESULTS The group fed a high-fat diet had significantly (p ˂ 0.05) increased body weight, BP, and HR and higher levels of urine albumin, serum noradrenaline (NE), and angiotensin II (AngII) than the control group. The sham-surgery group and RDN group also had higher levels than the control group (p ˂ 0.05). Compared with the sham-surgery group, the RDN group had lower BP, urine albumin, serum NE, and AngII and less fibrotic tissue (all p ˂ 0.05). CONCLUSION RDN reduced BP, slowed progression of albuminuria, and suppressed renal remodeling in a canine model of high-fat diet-induced hypertension.
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Affiliation(s)
- Liying Gong
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China.,Department of Clinical Pharmacology Center, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Fenglin Jiang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China,
| | - Zhihui Zhang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Xinguo Wang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Hui Li
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Yan Kuang
- Department of Cardiology, The Third Xiangya Hospital of Central South University, Changsha, China
| | - Guoping Yang
- Department of Clinical Pharmacology Center, The Third Xiangya Hospital of Central South University, Changsha, China
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6
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Reckelhoff JF. Androgens and Blood Pressure Control: Sex Differences and Mechanisms. Mayo Clin Proc 2019; 94:536-543. [PMID: 30713048 PMCID: PMC6546172 DOI: 10.1016/j.mayocp.2018.11.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/19/2018] [Accepted: 11/20/2018] [Indexed: 01/13/2023]
Abstract
The role that androgens play in mediating elevated blood pressure is unclear. Low levels of androgens in men and increased levels of androgens in women, as occurs with polycystic ovary syndrome (PCOS), are both associated with increased risk for cardiovascular disease and elevated blood pressure. We have used animal models to evaluate the potential mechanisms by which men and women have differential responses to androgens that affect regulation of blood pressure and the implications these may have for the health of men and women.
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Affiliation(s)
- Jane F Reckelhoff
- Department of Cell and Molecular Biology, Mississippi Center of Excellence in Perinatal Research and Women's Health Research Center, University of Mississippi Medical Center, Jackson.
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7
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Reckelhoff JF. Sex Differences in Regulation of Blood Pressure. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018; 1065:139-151. [PMID: 30051382 DOI: 10.1007/978-3-319-77932-4_9] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Hypertension is one of the leading risk factors for cardiovascular disease, myocardial infarction, and stroke. There are gender differences in the prevalence of hypertension and in the mechanisms responsible for hypertension in humans. This review will discuss the mechanisms for regulation of blood pressure, sex differences that have been identified in animal studies, and the gender differences that have been identified in humans.
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Affiliation(s)
- Jane F Reckelhoff
- Department of Cell and Molecular Biology and Women's Health Research Center and The Mississippi Center of Excellence in Perinatal Research, University of Mississippi Medical Center, Jackson, MS, USA.
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8
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Dalmasso C, Patil CN, Yanes Cardozo LL, Romero DG, Maranon RO. Cardiovascular and Metabolic Consequences of Testosterone Supplements in Young and Old Male Spontaneously Hypertensive Rats: Implications for Testosterone Supplements in Men. J Am Heart Assoc 2017; 6:JAHA.117.007074. [PMID: 29042425 PMCID: PMC5721890 DOI: 10.1161/jaha.117.007074] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Background The safety of testosterone supplements in men remains unclear. In the present study, we tested the hypothesis that in young and old male spontaneously hypertensive rats (SHR), long‐term testosterone supplements increase blood pressure and that the mechanism is mediated in part by activation of the renin‐angiotensin system. Methods and Results In untreated males, serum testosterone exhibited a sustained decrease after 5 months of age, reaching a nadir by 18 to 22 months of age. The reductions in serum testosterone were accompanied by an increase in body weight until very old age (18 months). Testosterone supplements were given for 6 weeks to young (12 weeks‐YMSHR) and old (21–22 months‐OMSHR) male SHR that increased serum testosterone by 2‐fold in young males and by 4‐fold in old males. Testosterone supplements decreased body weight, fat mass, lean mass, and plasma leptin, and increased plasma estradiol in YMSHR but had no effect in OMSHR. Mean arterial pressure (MAP) was significantly higher in OMSHR than in YMSHR and testosterone supplements decreased MAP in OMSHR, but significantly increased MAP in YMSHR. Enalapril, the angiotensin‐converting enzyme inhibitor, reduced MAP in both control and testosterone‐supplemented YMSHR, but had a greater effect on MAP in testosterone‐treated rats, suggesting the mechanism responsible for the increase in MAP in YMSHR is mediated at least in part by activation of the renin‐angiotensin system. Conclusions Taken together with previous studies, these data suggest that testosterone supplements may have differential effects on men depending on age, cardiovascular and metabolic status, and dose and whether given long‐term or short‐term.
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Affiliation(s)
- Carolina Dalmasso
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS.,Department of Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS
| | - Chetan N Patil
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS.,Department of Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS
| | - Licy L Yanes Cardozo
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS.,Department of Medicine, Divisions of Endocrinology/Nephrology, University of Mississippi Medical Center, Jackson, MS.,Department of Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS
| | - Damian G Romero
- Department of Biochemistry, University of Mississippi Medical Center, Jackson, MS.,Department of Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS
| | - Rodrigo O Maranon
- Department of Medicine, Divisions of Endocrinology/Nephrology, University of Mississippi Medical Center, Jackson, MS .,Department of Women's Health Research Center, University of Mississippi Medical Center, Jackson, MS
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9
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Abstract
The objective of this review is to provide an in-depth evaluation of how renal nerves regulate renal and cardiovascular function with a focus on long-term control of arterial pressure. We begin by reviewing the anatomy of renal nerves and then briefly discuss how the activity of renal nerves affects renal function. Current methods for measurement and quantification of efferent renal-nerve activity (ERNA) in animals and humans are discussed. Acute regulation of ERNA by classical neural reflexes as well and hormonal inputs to the brain is reviewed. The role of renal nerves in long-term control of arterial pressure in normotensive and hypertensive animals (and humans) is then reviewed with a focus on studies utilizing continuous long-term monitoring of arterial pressure. This includes a review of the effect of renal-nerve ablation on long-term control of arterial pressure in experimental animals as well as humans with drug-resistant hypertension. The extent to which changes in arterial pressure are due to ablation of renal afferent or efferent nerves are reviewed. We conclude by discussing the importance of renal nerves, relative to sympathetic activity to other vascular beds, in long-term control of arterial pressure and hypertension and propose directions for future research in this field. © 2017 American Physiological Society. Compr Physiol 7:263-320, 2017.
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Affiliation(s)
- John W Osborn
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
| | - Jason D Foss
- Department of Integrative Biology and Physiology, Medical School, University of Minnesota, Minneapolis, Minnesota, USA
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10
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Maranon RO, Reckelhoff JF. Mechanisms responsible for postmenopausal hypertension in a rat model: Roles of the renal sympathetic nervous system and the renin-angiotensin system. Physiol Rep 2016; 4:4/2/e12669. [PMID: 26811052 PMCID: PMC4760383 DOI: 10.14814/phy2.12669] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Hypertension in postmenopausal women is less well controlled than in age‐matched men. The aging female SHR is a model of postmenopausal hypertension that is mediated in part by activation of the renin–angiotensin system (RAS) and by the renal sympathetic nervous system. In this study, the hypothesis was tested that renal denervation would lower the blood pressure in old female SHR and would attenuate the antihypertensive effects of AT1 receptor antagonism. Retired breeder female SHR were subjected to right uninephrectomy (UNX) and left renal denervation (RD) or UNX and sham, and 2 weeks later, baseline mean arterial pressure (MAP; radiotelemetry) was measured for 4 days, and then rats were treated with angiotensin (AT1) receptor antagonist, losartan (40 mg/kg/day po) for 6 days. Renal denervation reduced MAP in old females compared to sham (172 ± 6 vs. 193 ± 6 mm Hg; P < 0.05). Losartan reduced MAP in both sham and RD rats similarly (numerically and by percentage) (142 ± 10 vs. 161 ± 6 mm Hg; P < 0.05 vs. RD, P < 0.05 vs. baseline). However, female SHR rats remained significantly hypertensive despite both pharmacological intervention and RD. The data suggest that both the renal sympathetic nervous system and the RAS have independent effects to control the blood pressure in old female SHR. Since the denervated rats treated with losartan remained hypertensive, the data also suggest that other mechanisms than the RAS and renal sympathetic nervous system contribute to the hypertension in old female SHR. The data also suggest that multiple mechanisms may mediate the elevated blood pressure in postmenopausal women.
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Affiliation(s)
- Rodrigo O Maranon
- Women's Health Research Center, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jane F Reckelhoff
- Women's Health Research Center, Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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11
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Fink GD, Phelps JT. Can we predict the blood pressure response to renal denervation? Auton Neurosci 2016; 204:112-118. [PMID: 27530600 DOI: 10.1016/j.autneu.2016.07.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 07/08/2016] [Accepted: 07/29/2016] [Indexed: 12/31/2022]
Abstract
Renal denervation (RDN) is a new therapy used to treat drug-resistant hypertension in the clinical setting. Published human trials show substantial inter-individual variability in the blood pressure (BP) response to RDN, even when technical aspects of the treatment are standardized as much as possible between patients. Widespread acceptance of RDN for treating hypertension will require accurate identification of patients likely to respond to RDN with a fall in BP that is clinically significant in magnitude, well-maintained over time and does not cause adverse consequences. In this paper we review and evaluate clinical studies that address possible predictors of the BP response to RDN. We conclude that only one generally reliable predictor has been identified to date, namely pre-RDN BP level, although there is some evidence for a few other factors. Experimental interventions in laboratory animals provide the opportunity to explore potential predictors that are difficult to investigate in human patients. Therefore we also describe results (from our lab and others) with RDN in spontaneously hypertensive rats. Since virtually all patients receiving RDN are taking three or more antihypertensive drugs, a particular focus of our work was on how ongoing antihypertensive drug treatment might alter the BP response to RDN. We conclude that patient age (or duration of hypertension) and concomitant treatment with certain drugs can affect the blood pressure response to RDN and that this information could help predict a favorable clinical response.
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Affiliation(s)
- Gregory D Fink
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48840, USA.
| | - Jeremiah T Phelps
- Department of Pharmacology and Toxicology, Michigan State University, 1355 Bogue Street, East Lansing, MI 48840, USA.
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12
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Mathis KW. An impaired neuroimmune pathway promotes the development of hypertension in systemic lupus erythematosus. Am J Physiol Regul Integr Comp Physiol 2015; 309:R1074-7. [PMID: 26084696 DOI: 10.1152/ajpregu.00143.2015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Accepted: 06/15/2015] [Indexed: 11/22/2022]
Abstract
Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disorder that affects nearly 2 million people in the United States. The majority of SLE cases occur in women at an age in which the prevalence of hypertension and cardiovascular disease is typically low. However, women with SLE have a high prevalence of hypertension for reasons that remain unclear. Because immune cells and chronic inflammation have been implicated in the pathogenesis of both hypertension and SLE and because inflammation has been shown to be regulated by the autonomic nervous system, studies investigating neuroimmune mechanisms of hypertension could have direct and significant clinical implications. The purpose of this review is to introduce a recently described neuroimmune pathway and discuss its potential importance in the development of hypertension and renal injury during SLE.
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Affiliation(s)
- Keisa W Mathis
- Department of Integrative Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas
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13
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Herlan L, Unland J, Langer S, Schulte L, Schütten S, García-Prieto CF, Kossmehl P, Fernández-Alfonso MS, Schulz A, Kreutz R. Development of progressive albuminuria in male Munich Wistar Frömter rats is androgen dependent. Physiol Genomics 2015; 47:281-9. [PMID: 25969455 DOI: 10.1152/physiolgenomics.00008.2015] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Accepted: 05/11/2015] [Indexed: 11/22/2022] Open
Abstract
Munich Wistar Frömter (MWF) rats develop spontaneous albuminuria that is linked to autosomal genetic loci and inherit a nephron deficit in both female and male animals, respectively. However, albuminuria and kidney damage are clearly more pronounced in males. Here we tested whether androgens and the androgen receptor influence albuminuria in male MWF. We first demonstrated in a pilot study that orchiectomy (Ox) of male MWF led to a significant suppression of urinary albumin excretion (UAE), while continuous testosterone supplementation in MWF Ox led to UAE levels similar to sham-operated (Sham) MWF rats. Subsequently, we performed a comparative main study between male MWF and normal Wistar rats to evaluate the effect of the androgen receptor on UAE development in adult animals up to the age of 18 wk. MWF Sham developed a marked increase in UAE compared with Wistar Sham (48.30 ± 6.16 vs. 0.42 ± 0.08 mg/24 h, P < 0.0001). UAE was significantly lower in MWF Ox compared with MWF Sham (-55%, P < 0.0001). In MWF Ox animals supplemented with testosterone and treated with the androgen receptor antagonist flutamide (OxTF) UAE at 18 wk was even lower compared with MWF Ox (-71%, P < 0.01) and similar to age-matched female MWF. The mRNA expression of renal tubular injury markers Kim1 and NGAL was increased in MWF Sham compared with Wistar Sham (P < 0.0008, respectively) and expression decreased significantly in MWF OxTF (P < 0.0004, respectively). Thus, the sexual dimorphism in albuminuria development in MWF can be attributed to testosterone and the androgen receptor in male rats.
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Affiliation(s)
- Laura Herlan
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Johannes Unland
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sebastian Langer
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Leonard Schulte
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Sabrina Schütten
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Concha F García-Prieto
- Departamento de Ciencias Farmacéuticas y de la Salud, Facultad de Farmacia, Universidad CEU-San Pablo, Madrid, Spain; and
| | - Peter Kossmehl
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | | | - Angela Schulz
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany
| | - Reinhold Kreutz
- Department of Clinical Pharmacology and Toxicology, Charité Centrum für Therapieforschung, Charité - Universitätsmedizin Berlin, Berlin, Germany;
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14
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Maranon R, Lima R, Spradley FT, do Carmo JM, Zhang H, Smith AD, Bui E, Thomas RL, Moulana M, Hall JE, Granger JP, Reckelhoff JF. Roles for the sympathetic nervous system, renal nerves, and CNS melanocortin-4 receptor in the elevated blood pressure in hyperandrogenemic female rats. Am J Physiol Regul Integr Comp Physiol 2015; 308:R708-13. [PMID: 25695289 DOI: 10.1152/ajpregu.00411.2014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2014] [Accepted: 02/17/2015] [Indexed: 01/22/2023]
Abstract
Women with polycystic ovary syndrome (PCOS) have hyperandrogenemia and increased prevalence of risk factors for cardiovascular disease, including elevated blood pressure. We recently characterized a hyperandrogenemic female rat (HAF) model of PCOS [chronic dihydrotestosterone (DHT) beginning at 4 wk of age] that exhibits similar characteristics as women with PCOS. In the present studies we tested the hypotheses that the elevated blood pressure in HAF rats is mediated in part by sympathetic activation, renal nerves, and melanocortin-4 receptor (MC4R) activation. Adrenergic blockade with terazosin and propranolol or renal denervation reduced mean arterial pressure (MAP by telemetry) in HAF rats but not controls. Hypothalamic MC4R expression was higher in HAF rats than controls, and central nervous system MC4R antagonism with SHU-9119 (1 nmol/h icv) reduced MAP in HAF rats. Taking a genetic approach, MC4R null and wild-type (WT) female rats were treated with DHT or placebo from 5 to 16 wk of age. MC4R null rats were obese and had higher MAP than WT control rats, and while DHT increased MAP in WT controls, DHT failed to further increase MAP in MC4R null rats. These data suggest that increases in MAP with chronic hyperandrogenemia in female rats are due, in part, to activation of the sympathetic nervous system, renal nerves, and MC4R and may provide novel insights into the mechanisms responsible for hypertension in women with hyperandrogenemia such as PCOS.
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Affiliation(s)
- Rodrigo Maranon
- Department of Physiology and Biophysics, Women's Health Research Center
| | - Roberta Lima
- Department of Physiology and Biophysics, Women's Health Research Center
| | - Frank T Spradley
- Department of Physiology and Biophysics, Women's Health Research Center, Cardiovascular Renal Research Center, and
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, Women's Health Research Center, Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, Mississippi
| | | | | | - Elizabeth Bui
- Department of Physiology and Biophysics, Women's Health Research Center
| | | | | | - John E Hall
- Department of Physiology and Biophysics, Cardiovascular Renal Research Center, and Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, Mississippi
| | - Joey P Granger
- Department of Physiology and Biophysics, Women's Health Research Center, Cardiovascular Renal Research Center, and
| | - Jane F Reckelhoff
- Department of Physiology and Biophysics, Women's Health Research Center, Cardiovascular Renal Research Center, and
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Loria AS, Brinson KN, Fox BM, Sullivan JC. Sex-specific alterations in NOS regulation of vascular function in aorta and mesenteric arteries from spontaneously hypertensive rats compared to Wistar Kyoto rats. Physiol Rep 2014; 2:2/8/e12125. [PMID: 25168874 PMCID: PMC4246578 DOI: 10.14814/phy2.12125] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
The present study tested the hypothesis that spontaneously hypertensive rats (SHR) have impaired nitric oxide synthase (NOS)‐mediated regulation of vascular function versus Wistar‐Kyoto rats (WKY). Aorta and small mesenteric arteries were studied from male and female SHR (M SHR and F SHR) and WKY (M WKY and F WKY). Phenylephrine (PE)‐induced vasoconstriction was greater in aorta of M SHR versus all others (P < 0.05); there were neither sex nor strain differences in PE contraction in mesenteric arteries. The NOS inhibitor l‐Nitro‐Arginine Methyl Ester (l‐NAME) increased PE‐induced vasoconstriction in all rats, although the increase was the least in male SHR (P < 0.05), revealing a blunted vasoconstrictor buffering capacity of NOS. l‐NAME increased sensitivity to PE‐induced constriction only in mesenteric arteries of SHR, although, the maximal percent increase in contraction was comparable among groups. ACh‐induced relaxation was also less in aorta from M SHR versus all others (P < 0.05). ACh relaxation was comparable among groups in mesenteric arteries, although SHR exhibited a greater NOS component to ACh‐induced relaxation than WKY. To gain mechanistic insight into sex and strain differences in vascular function, NOS activity and NOS3 protein expression were measured. Aortic NOS activity was comparable between groups and M SHR had greater NOS3 expression than M WKY. In contrast, although vascular function was largely maintained in mesenteric arteries of SHR, NOS activity was less in SHR versus WKY. In conclusion, M SHR exhibit a decrease in NOS regulation of vascular function compared to F SHR and WKY, although this is not mediated by decreases in NOS activity and/or expression. The present study tested the hypothesis that spontaneously hypertensive rats (SHR) have impaired nitric oxide synthase (NOS)‐mediated regulation of vascular function versus Wistar‐Kyoto rats (WKY). Aorta and small mesenteric arteries were studied from male and female SHR and WKY. Male SHR showed a decreased NOS regulation of vascular function compared to F SHR and WKY, although this was not mediated by decreases in NOS activity and/or expression.
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Affiliation(s)
- Analia S Loria
- Department of Pharmacology and Nutritional Sciences, University of Kentucky, St. Lexington, Kentucky
| | - Krystal N Brinson
- Department of Physiology, Georgia Regents University, Augusta, Georgia
| | - Brandon M Fox
- Department of Physiology, Georgia Regents University, Augusta, Georgia
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Moulana M, Hosick K, Stanford J, Zhang H, Roman RJ, Reckelhoff JF. Sex differences in blood pressure control in SHR: lack of a role for EETs. Physiol Rep 2014; 2:2/5/e12022. [PMID: 24844641 PMCID: PMC4098748 DOI: 10.14814/phy2.12022] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
The mechanisms responsible for the gender difference in blood pressure (BP) in humans are not clear. Over the past several years we have studied the spontaneously hypertensive rat (SHR) as a model of sex differences in BP control. In the present study, we tested the hypothesis that renal vascular and microsomal epoxyeicosatrienoic acid (EET) levels are higher in females than males, and increasing vascular EETs by blocking epoxide hydrolase with AUDA will reduce BP more in males than females. Renal vascular and microsomal EETs were higher in female SHR than males. Mean arterial pressure (MAP by telemetry) was higher in males than females during the baseline period of 6 days, and although the epoxide hydrolase inhibitor, AUDA, given for 10 days increased renal microvascular EETs in both groups, AUDA did not affect MAP in either group. These data suggest that EETs do not contribute to the sex differences in hypertension in young SHR.
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Affiliation(s)
- Mohadetheh Moulana
- Department of Psychiatry, University of Mississippi Medical Center, Jackson, Mississippi
| | - Karen Hosick
- Women's Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - James Stanford
- Women's Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi
| | - Huimin Zhang
- Women's Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Richard J Roman
- Women's Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Jane F Reckelhoff
- Women's Health Research Center, University of Mississippi Medical Center, Jackson, Mississippi Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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Abstract
PURPOSE This review highlights the physiological mechanisms underlying the neural regulation of the kidney, normally to maintain cardiovascular homeostasis, and in pathophysiological states of hypertension and renal disease. It is relevant because of the demonstration that bilateral renal denervation in different hypertensive groups causes a sustained reduction in blood pressure. RECENT FINDINGS There are patients groups in whom their hypertension is resistant to antihypertensive drugs or with renal diseases in which they are contraindicated. Recently, medical devices have been developed to manipulate the sympathetic nervous system, for example, implantation of carotid sinus nerve stimulating electrodes and ablation of the renal innervation. These approaches have been relatively successful but there remains a lack of understanding of the neural mechanisms impinging on the kidney that regulate long-term control of blood pressure. SUMMARY The observation that bilateral renal nerve ablation can reduce blood pressure represents an important therapeutic milestone. Nonetheless, questions arise as to the underlying mechanisms, the long-term consequences, whether there may be re-innervation over a number of years, or whether some unknown consequence to the denervation may arise. This may point to the development of novel compounds targeted to the innervation of the kidney.
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Maranon RO, Lima R, Mathbout M, do Carmo JM, Hall JE, Roman RJ, Reckelhoff JF. Postmenopausal hypertension: role of the sympathetic nervous system in an animal model. Am J Physiol Regul Integr Comp Physiol 2013; 306:R248-56. [PMID: 24381180 DOI: 10.1152/ajpregu.00490.2013] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In postmenopausal women the mechanisms responsible for hypertension have not been completely elucidated, and there are no gender-specific guidelines for women despite studies showing that blood pressure is not as well controlled to goal in women as in men. In the present study we tested the hypotheses that the sympathetic nervous system and the renal sympathetic nerves contribute to hypertension in aging female rats, that sympathetic activation may be mediated by the melanocortin 3/4 receptor (MC3/4R), and that MC3/4R activation may be due to increases in leptin. α-1, β-1,2-Adrenergic blockade reduced blood pressure in both young (3-4 mo) and old (18-19 mo) female spontaneously hypertensive rats (SHR). Renal denervation attenuated the hypertension more in old females than young females. MC3/4R antagonism with SHU-9119 given intracerebroventricularly had no effect on blood pressure in either young or old females but significantly reduced blood pressure in old males. Plasma leptin levels were similar in old male and female SHR and in old versus young females. These data suggest that the hypertension in old female SHR is in part due to activation of the sympathetic nervous system, that the renal nerves contribute to the hypertension, and that the mechanism responsible for sympathetic activation in old females is independent of the MC3/4R.
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Abstract
Hypertension is a complex and multifaceted disease, and there are well established sex differences in many aspects of blood pressure (BP) control. The intent of this review is to highlight recent work examining sex differences in the molecular mechanisms of BP control in hypertension to assess whether the "one-size-fits-all" approach to BP control is appropriate with regard to sex.
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Abstract
In recent years, the interest in studying the impact of sex steroids and gender on the regulation of blood pressure and cardiovascular disease has been growing. Women are protected from most cardiovascular events compared with men until after menopause, and postmenopausal women are at increased risk of cardiovascular complications compared with premenopausal women. The pathophysiological mechanisms have not been elucidated, but are not likely to be as simple as the presence or absence of oestrogens, since hormone replacement therapy in elderly women in the Women's Health Initiative or HERS (Heart and Estrogen/progestin Replacement Study) did not provide primary or secondary prevention against cardiovascular events. Men are also thought to be at risk of cardiovascular disease at earlier ages than women, and these mechanisms too are not likely to be as simple as the presence of testosterone, since androgen levels fall in men with cardiovascular and other chronic diseases. In fact, many investigators now believe that it is the reduction in androgen levels that frequently accompanies chronic disease and may exacerbate cardiovascular disease in men. In the present review, the roles of sex steroids and gender in mediating or protecting against hypertension and cardiovascular disease will be discussed.
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Affiliation(s)
- Rodrigo Maranon
- Women's Health Research Center and Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS 39216-4505, USA
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21
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Mathis KW, Venegas-Pont M, Flynn ER, Williams JM, Maric-Bilkan C, Dwyer TM, Ryan MJ. Hypertension in an experimental model of systemic lupus erythematosus occurs independently of the renal nerves. Am J Physiol Regul Integr Comp Physiol 2013; 305:R711-9. [PMID: 23926131 DOI: 10.1152/ajpregu.00602.2012] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Systemic lupus erythematosus (SLE) is a chronic inflammatory disorder with prevalent hypertension and renal injury. In this study, we tested whether the renal nerves contribute to the development of hypertension in an established mouse model of SLE (NZBWF1). Female SLE and control (NZW/LacJ) mice were subjected to either bilateral renal denervation or a sham procedure at 32 wk of age. Two weeks later, blood pressure was assessed in conscious mice using carotid artery catheters. Blood pressure was higher in SLE mice compared with controls, as previously reported; however, blood pressure was not altered in the denervated SLE or control mice. The development of albuminuria was markedly blunted in denervated SLE mice; however, glomerulosclerosis was increased. Renal denervation reduced renal cortical expression of monocyte-chemoattractant protein in SLE mice but did not significantly alter renal monocyte/macrophage infiltration. Renal cortical TNF-α expression was also increased in sham SLE mice, but this was not impacted by denervation. This study suggests that the renal nerves do not have a significant role in the pathogenesis of hypertension, but have a complex effect on the associated renal inflammation and renal injury.
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Affiliation(s)
- Keisa W Mathis
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi; and
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22
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Lei B, Nakano D, Fujisawa Y, Liu Y, Hitomi H, Kobori H, Mori H, Masaki T, Asanuma K, Tomino Y, Nishiyama A. N-type calcium channel inhibition with cilnidipine elicits glomerular podocyte protection independent of sympathetic nerve inhibition. J Pharmacol Sci 2012; 119:359-67. [PMID: 22863666 DOI: 10.1254/jphs.12075fp] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
We recently demonstrated that cilnidipine, an L/N-type calcium channel blocker, elicits protective effects against glomerular podocyte injury, in particular, in obese hypertensive rats that express the N-type calcium channel (N-CC). Since the N-CC is known to be expressed in sympathetic nerve endings, we evaluated the reno-protective effects of cilnidipine in innervated and denervated spontaneously hypertensive rats (SHR). Male SHR were uninephrectomized and fed 4% high-salt diet (HS-UNX-SHR). Animals were divided into groups, as follows, and observed from 9 to 27 weeks of age: 1) vehicle (n = 14), 2) vehicle plus renal-denervation (n = 15), 3) cilnidipine (50 mg/kg per day, p.o.; n = 10), and 4) cilnidipine plus renal-denervation (n = 15). Renal denervation attenuated elevations in blood pressure, but failed to suppress urinary protein excretion and podocyte injury in HS-UNX-SHR. Cilnidipine in both innervated and denervated HS-UNX-SHR similarly induced significant antihypertensive effects, as well as suppressing the urinary protein excretion and podocyte injury, compared to vehicle-treated HS-UNX-SHR. These data indicate that renal nerves have a limited contribution to the cilnidipine-induced reno-protective effects in HS-UNX-SHR.
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Affiliation(s)
- Bai Lei
- Department of Pharmacology, Kagawa University Medical School, Japan
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Yanes LL, Romero DG, Iliescu R, Zhang H, Davis D, Reckelhoff JF. Postmenopausal hypertension: role of the Renin-Angiotensin system. Hypertension 2010; 56:359-63. [PMID: 20679182 DOI: 10.1161/hypertensionaha.110.152975] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
After menopause, blood pressure increases in women. However, the underlying mechanisms responsible for postmenopausal hypertension are not completely understood. This study was conducted to determine the role that the renin-angiotensin system (RAS) plays in post-menopausal hypertension. Post-estrous cycling (postmenopausal) spontaneously hypertensive rats or young female controls were treated with losartan, an angiotensin (Ang) II type 1 receptor blocker, for 25 days. Mean arterial pressure was recorded continuously by radiotelemetry. Losartan significantly decreased blood pressure in postmenopausal rats and young female controls but failed to normalize blood pressure in postmenopausal rats to levels found in young controls. Plasma renin activity and plasma angiotensinogen were significantly elevated, and intrarenal Ang II type 1 receptor and renin mRNA expression were significantly downregulated in postmenopausal rats. Therefore, RAS only partially contributes to hypertension in postcycling spontaneously hypertensive rats, whereas hypertension in young females is mediated mainly by the RAS. The data suggest that other mechanisms besides activation of the RAS are likely involved in postmenopausal hypertension.
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Affiliation(s)
- Licy L Yanes
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 N State Street, Jackson, MS 39216-4505, USA
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Lopez-Ruiz AF, Iliescu R, Reckelhoff JF. Refractory blood pressure in female SHR to increased oxidative stress is not mediated by NO or by upregulation of renal antioxidant enzymes. Am J Physiol Regul Integr Comp Physiol 2009; 298:R266-71. [PMID: 20018822 DOI: 10.1152/ajpregu.00471.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
There is a sex difference in the blood pressure (BP) responses to prooxidants and antioxidants in the spontaneously hypertensive rat (SHR). In contrast to males, BP in female SHR does not decrease in response to antioxidants, such as tempol or apocynin, or increase in response to the prooxidant, molsidomine. Molsidomine decreases BP and increases expression of antioxidants in male Wistar-Kyoto rats (WKY), but not male SHR. The present study tested the hypothesis that the mechanism responsible for the lack of a pressor response to molsidomine in females is due to higher endogenous nitric oxide (NO) or to compensatory upregulation of renal antioxidant enzymes. Female SHR were treated with molsidomine in the presence or absence of nitro-L-arginine methyl ester (L-NAME) for 2 wk. Molsidomine increased nitrate/nitrite (NO(x)) and F2-isoprostane (F2-IsoP) excretion, whereas L-NAME reduced NO(x) but increased F-Isop. Molsidomine and L-NAME together further reduced NO(x) and increased F2-IsoP. Molsidomine alone had no effect on BP; L-NAME alone increased BP. The combination of molsidomine and L-NAME did not increase BP above L-NAME alone levels. Whole body and renal oxidative stress increased, while renal cortical Cu,Zn-SOD expression was downregulated and catalase was upregulated by molsidomine; glutathione peroxidase expression was unaffected. These data support our previous studies suggesting that BP in female SHR is independent of either increases or decreases in oxidative stress. The mechanisms responsible for the sex difference in BP response to increase or decrease of oxidative stress are not due to increased NO in females or to compensatory upregulation of antioxidant enzymes in response to increases in oxidants.
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Affiliation(s)
- Arnaldo F Lopez-Ruiz
- Dept. of Physiology and Biophysics, Univ. of Mississippi Medical Center, 2500 North State St., Jackson, MS 39216-4505, USA
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de Vendômois JS, Roullier F, Cellier D, Séralini GE. A comparison of the effects of three GM corn varieties on mammalian health. Int J Biol Sci 2009; 5:706-26. [PMID: 20011136 PMCID: PMC2793308 DOI: 10.7150/ijbs.5.706] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Accepted: 11/17/2009] [Indexed: 11/23/2022] Open
Abstract
We present for the first time a comparative analysis of blood and organ system data from trials with rats fed three main commercialized genetically modified (GM) maize (NK 603, MON 810, MON 863), which are present in food and feed in the world. NK 603 has been modified to be tolerant to the broad spectrum herbicide Roundup and thus contains residues of this formulation. MON 810 and MON 863 are engineered to synthesize two different Bt toxins used as insecticides. Approximately 60 different biochemical parameters were classified per organ and measured in serum and urine after 5 and 14 weeks of feeding. GM maize-fed rats were compared first to their respective isogenic or parental non-GM equivalent control groups. This was followed by comparison to six reference groups, which had consumed various other non-GM maize varieties. We applied nonparametric methods, including multiple pairwise comparisons with a False Discovery Rate approach. Principal Component Analysis allowed the investigation of scattering of different factors (sex, weeks of feeding, diet, dose and group). Our analysis clearly reveals for the 3 GMOs new side effects linked with GM maize consumption, which were sex- and often dose-dependent. Effects were mostly associated with the kidney and liver, the dietary detoxifying organs, although different between the 3 GMOs. Other effects were also noticed in the heart, adrenal glands, spleen and haematopoietic system. We conclude that these data highlight signs of hepatorenal toxicity, possibly due to the new pesticides specific to each GM corn. In addition, unintended direct or indirect metabolic consequences of the genetic modification cannot be excluded.
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Lopez-Ruiz A, Sartori-Valinotti J, Yanes LL, Iliescu R, Reckelhoff JF. Sex differences in control of blood pressure: role of oxidative stress in hypertension in females. Am J Physiol Heart Circ Physiol 2008; 295:H466-74. [PMID: 18567715 PMCID: PMC2519220 DOI: 10.1152/ajpheart.01232.2007] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
In general, blood pressure is higher in normotensive men than in age-matched women, and the prevalence of hypertension in men is also higher until after menopause, when the prevalence of hypertension increases for women. It is likely then that the mechanisms by which blood pressure increases in men and women with aging may be different. Although clinical trials to reduce blood pressure with antioxidants have typically not been successful in human cohorts, studies in male rats suggest that oxidative stress plays an important role in mediating hypertension. The exact mechanisms by which oxidative stress increases blood pressure have not been completely elucidated. There may be several reasons for the discrepancies between clinical and animal studies. In this review, the data obtained in selected clinical and animal studies are discussed, and the hypothesis is put forward that oxidative stress may not be as important in mediating hypertension in females as has been shown previously in male rats. Furthermore, it is likely that differences in genetics, age, length of time with hypertension, endothelial dysfunction, and sex are all factored in to modulate the responses to antioxidants in humans. As such, future clinical trials should be designed and powered to evaluate the effects of oxidative stress on blood pressure separately in men and women.
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Affiliation(s)
- Arnaldo Lopez-Ruiz
- Dept. of Physiology and Biophysics, Univ. of Mississippi Medical Center, 2500 North State St., Jackson, MS 39216-4505, USA
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Riazi S, Madala-Halagappa VK, Dantas AP, Hu X, Ecelbarger CA. Sex differences in renal nitric oxide synthase, NAD(P)H oxidase, and blood pressure in obese Zucker rats. ACTA ACUST UNITED AC 2008; 4:214-29. [PMID: 18022589 DOI: 10.1016/s1550-8579(07)80042-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2007] [Indexed: 01/11/2023]
Abstract
BACKGROUND By increasing renal oxidative stress, obesity may alter the protective effect of female sex on blood pressure (BP). OBJECTIVES The aim of this study was to determine whether female rats had altered expression and activity of renal nicotinamide adenine dinucleotide (phosphate) [NAD(P)H] oxidase and nitric oxide synthase (NOS), enzymes important in superoxide and nitric oxide generation, respectively, and whether this relationship was altered in obesity. METHODS Male and female, lean and obese Zucker rats were fed progressively higher levels of NaCl over 54 days while BP was measured by radiotelemetry. Kidneys were harvested after euthanization. RESULTS A total of 32 (n=8/body type/sex) Zucker rats were examined. On a high-salt diet (4% NaC1), male and obese rats had significantly higher mean arterial blood pressure relative to female and lean rats (mm Hg: lean male=108, lean female=99, obese male=129, and obese female=123) and reduced renal cortical NOS activity (determined by 2-way analysis of variance; P<0.05 for sex and body type). Immunoblotting revealed that cortical endothelial NOS protein abundance was reduced in obese but not in male rats. Surprisingly, lean female rats had the highest outer medullary protein levels of several NADPH oxidase subunits, including gp91phox, p47phox, and p67phox (% of lean male: 207, 196, and 151, respectively; P<0.01 for all). However, renal NADPH activity was not increased in lean females, but was significantly increased in obese rats of both sexes (P<0.05). CONCLUSIONS High-NaCl diet increased BP modestly in obese females, but not at all in lean females, suggesting some loss of protection with obesity in female rats. Reduced cortical NOS activity (both in male and obese rats) and/or increased NADPH oxidase activity (obese rats) may have contributed to increased salt sensitivity of BP.
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Affiliation(s)
- Shahla Riazi
- Division of Endocrinology and Metabolism, Department of Medicine, Georgetown University, Washington, DC 20007, USA
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Maser RE, Lenhard MJ, Rizzo AA, Vasile AA. Continuous positive airway pressure therapy improves cardiovascular autonomic function for persons with sleep-disordered breathing. Chest 2007; 133:86-91. [PMID: 17951618 DOI: 10.1378/chest.07-1580] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
BACKGROUND Sleep-disordered breathing (SDB) is an independent risk factor for cardiovascular morbidity. Dysfunction of the cardiovascular autonomic nervous system may be a potential mechanism whereby SDB is linked to cardiovascular disease. Repetitive sympathetic activation during apneic episodes may impair cardiovascular reflex function, and increased sympathetic activity can stimulate renin release. Given that patients with SDB may have reduced cardiovascular autonomic function, the purpose of this study was to determine whether treatment with continuous positive airway pressure (CPAP) for 6 weeks would improve autonomic function. METHODS Twenty-nine participants with a diagnosis of SDB, who completed 6 weeks of CPAP therapy, were evaluated for cardiovascular autonomic nerve fiber function at baseline and post therapy. Autonomic function tests included the following: R-R interval variation during deep breathing measured by vector analysis (ie, mean circular resultant [MCR]) and expiration/inspiration (E/I) ratio; and the Valsalva maneuver. Participants were also evaluated prior to CPAP therapy for plasma renin activity levels. RESULTS Participants in this study showed improved cardiovascular autonomic function after 6 weeks of treatment (baseline vs follow-up) as assessed by the mean (+/- SD) MCR (33.2 +/- 22.5 vs 36.9 +/- 24.2, respectively; p < 0.05) and E/I ratio (1.20 +/- 0.12 vs 1.24 +/- 0.14, respectively; p < 0.01). Improved vagal tone was also noted for subjects with elevated renin levels. CONCLUSIONS Treatment of SDB with CPAP for 6 weeks improved vagal tone and may be beneficial in reducing the risk of developing clinical manifestations of cardiovascular autonomic dysfunction (eg, increased risk of mortality).
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Affiliation(s)
- Raelene E Maser
- Department of Medical Technology, University of Delaware, Newark, DE 19716, USA.
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Stauss HM, Moffitt JA, Chapleau MW, Abboud FM, Johnson AK. Baroreceptor reflex sensitivity estimated by the sequence technique is reliable in rats. Am J Physiol Heart Circ Physiol 2006; 291:H482-3. [PMID: 16772526 DOI: 10.1152/ajpheart.00228.2006] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The following is the abstract of the article discussed in the subsequent letter: The function of the arterial baroreflex has traditionally been assessed by measurement of reflex changes in heart rate (HR) or sympathetic nerve activity resulting from experimenter-induced manipulation of arterial blood pressure (the Oxford method, also termed the pharmacological method). However, logistical and flexibility limitations of this technique have promoted the development of new methods for assessing baroreflex function such as the evaluation of changes in spontaneous arterial pressure and HR. Although this new spontaneous method has been validated in dogs and humans, it has not been rigorously tested in rats. In the present study, the method of correlating spontaneous changes in systolic blood pressure and HR was evaluated in resting, normotensive Sprague-Dawley rats. This technique was found to be neither reliable nor valid under the conditions employed in the present protocol. We also tested a variation of the spontaneous method that evaluates particular sequences of data during which arterial pressure and pulse interval are changing in the same direction for at least three consecutive heart beats (the sequence method). The sequence method did not provide extra reliability or validity over the spontaneous method. We conclude that due to the restricted range of variability obtained by measuring spontaneous blood pressure fluctuations, the spontaneous and sequence techniques do not provide data that are comparable to the traditional method of assessing HR changes triggered by arterial blood pressure increases and decreases induced by vasoactive drugs. However, it is possible that surgical stress obscured the relationship between blood pressure and HR, and therefore additional studies are needed to determine whether the spontaneous and sequence methods can be applied to rats during different behavioral states.
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