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Li P, Cai X, Xiao N, Ma X, Zeng L, Zhang LH, Xie L, Du B. Sacha inchi ( Plukenetia volubilis L.) shell extract alleviates hypertension in association with the regulation of gut microbiota. Food Funct 2020; 11:8051-8067. [PMID: 32852030 DOI: 10.1039/d0fo01770a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Dysbiosis of gut microbiota has been implicated in the pathogenesis of hypertension. A definite relationship between gut microbiota and hypertension remains intriguing. Here, we show that the Sacha inchi (Plukenetia volubilis L.) shell extract (SISE) intervention significantly reduced systolic blood pressures in spontaneous hypertensive rats (SHR), attenuated the oxidative damage and modulated plasma calcium homeostasis and left ventricular hypertrophy in both SHR and high-salt diet Wistar-Kyoto rats. SISE reshaped the gut microbiome and metabolome, particularly by improving the prevalence of Roseburia and dihydrofolic acid levels in the gut. Transcriptome analyses showed that the protective effects of SISE were accompanied by the modulation of renal molecular pathways, beneficial for cardiovascular functions such as the L-type voltage-dependent calcium channel (LTCC), a key regulator of calcium signaling. Overall, the results have shown that dietary SISE can alleviate hypertension regulating the gut microbiota, and Ca2+ signaling might be a potential target for spontaneous hypertension.
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Affiliation(s)
- Pan Li
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xin Cai
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Nan Xiao
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Xiaowei Ma
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Liping Zeng
- College of Food Science, South China Agricultural University, Guangzhou 510642, China
| | - Lian-Hui Zhang
- Guangdong Province Key Laboratory of Microbial Signals and Disease Control, Integrative Microbiology Research Centre, South China Agricultural University, Guangzhou 510642, China.
| | - Lanhua Xie
- Expert Research Station of Bing Du, Pu'er City, Yunnan 665000, China.
| | - Bing Du
- College of Food Science, South China Agricultural University, Guangzhou 510642, China and Expert Research Station of Bing Du, Pu'er City, Yunnan 665000, China.
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Abstract
PURPOSE OF REVIEW The main goal of this article is to discuss the role of the epithelial sodium channel (ENaC) in extracellular fluid and blood pressure regulation. RECENT FINDINGS Besides its role in sodium handling in the kidney, recent studies have found that ENaC expressed in other cells including immune cells can influence blood pressure via extra-renal mechanisms. Dendritic cells (DCs) are activated and contribute to salt-sensitive hypertension in an ENaC-dependent manner. We discuss recent studies on how ENaC is regulated in both the kidney and other sites including the vascular smooth muscles, endothelial cells, and immune cells. We also discuss how this extra-renal ENaC can play a role in salt-sensitive hypertension and its promise as a novel therapeutic target. The role of ENaC in blood pressure regulation in the kidney has been well studied. Recent human gene sequencing efforts have identified thousands of variants among the genes encoding ENaC, and research efforts to determine if these variants and their expression in extra-renal tissue play a role in hypertension will advance our understanding of the pathogenesis of ENaC-mediated cardiovascular disease and lead to novel therapeutic targets.
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Affiliation(s)
- Ashley L Pitzer
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Avenue, P415C Medical Research Building IV, Nashville, TN, 37232, USA
| | - Justin P Van Beusecum
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Avenue, P415C Medical Research Building IV, Nashville, TN, 37232, USA
| | - Thomas R Kleyman
- Departments of Medicine, Cell Biology, Pharmacology, and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Annet Kirabo
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University Medical Center, 2215 Garland Avenue, P415C Medical Research Building IV, Nashville, TN, 37232, USA. .,Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, USA.
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Alleviation of salt-induced exacerbation of cardiac, renal, and visceral fat pathology in rats with metabolic syndrome by surgical removal of subcutaneous fat. Nutr Diabetes 2020; 10:28. [PMID: 32778644 PMCID: PMC7417575 DOI: 10.1038/s41387-020-00132-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/29/2020] [Accepted: 07/29/2020] [Indexed: 12/22/2022] Open
Abstract
OBJECTIVES Evidence suggests that visceral adipose tissue (VAT) and subcutaneous adipose tissue (SAT) should be considered as distinct types of white fat. Although VAT plays a key role in metabolic syndrome (MetS), the role of subcutaneous adipose tissue (SAT) has been unclear. DahlS.Z-Leprfa/Leprfa (DS/obese) rats, an animal model of MetS, develop adipocyte hypertrophy and inflammation to similar extents in SAT and VAT. We have now investigated the effects of salt loading and SAT removal on cardiac, renal, and VAT pathology in DS/obese rats. METHODS DS/obese rats were subjected to surgical removal of inguinal SAT or sham surgery at 8 weeks of age. They were provided with a 0.3% NaCl solution as drinking water or water alone for 4 weeks from 9 weeks of age. RESULTS Salt loading exacerbated hypertension, insulin resistance, as well as left ventricular (LV) hypertrophy, inflammation, fibrosis, and diastolic dysfunction in DS/obese rats. It also reduced both SAT and VAT mass but aggravated inflammation only in VAT. Although SAT removal did not affect LV hypertrophy in salt-loaded DS/obese rats, it attenuated hypertension, insulin resistance, and LV injury as well as restored fat mass and alleviated inflammation and the downregulation of adiponectin gene expression in VAT. In addition, whereas salt loading worsened renal injury as well as upregulated the expression of renin-angiotensin-aldosterone system-related genes in the kidney, these effects were suppressed by removal of SAT. CONCLUSIONS SAT removal attenuated salt-induced exacerbation of MetS and LV and renal pathology in DS/obese rats. These beneficial effects of SAT removal are likely attributable, at least in part, to inhibition of both VAT and systemic inflammation.
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Prior exposure to placental ischemia causes increased salt sensitivity of blood pressure via vasopressin production and secretion in postpartum rats. J Hypertens 2020; 37:1657-1667. [PMID: 30950978 DOI: 10.1097/hjh.0000000000002091] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Women with a history of preeclampsia exhibit increased salt sensitivity of blood pressure at postpartum, which might be responsible for their increased risk of future cardiovascular diseases. However, it is unclear whether preeclampsia can cause increased salt sensitivity at postpartum. Vasopressin may play a role in the pathogenesis of preeclampsia and salt-sensitive hypertension. Therefore, the aim of this study was to determine whether the exposure to preeclampsia, as elicited by placental ischemia, causes increased salt sensitivity at postpartum, and if so, whether vasopressin is involved in its process. METHODS AND RESULTS We used a reduced uterine perfusion pressure (RUPP) rat model of preeclampsia. Pregnant Sprague-Dawley rats were categorized into the following two groups: RUPP-operated and sham-operated (SHAM) control groups. A 1-week-long high-salt diet was initiated at 3 weeks postpartum. The high-salt diet-induced increase in mean arterial pressure was significantly greater in the RUPP group than in the SHAM group. In addition, the plasma levels of copeptin, a substitute for plasma vasopressin, increased and serum osmolality decreased in the RUPP group. Double immunostaining revealed that the expression of c-Fos, a marker of neural activity, in vasopressin-producing neurons and presympathetic neurons in the hypothalamic paraventricular nucleus was significantly elevated in the RUPP group. The oral administration of conivaptan, the dual V1a/V2 vasopressin receptor antagonist, during high-salt diet abolished the enhanced increase in mean arterial pressure in RUPP rats. CONCLUSION Prior exposure to placental ischemia causes increased salt sensitivity of blood pressure at postpartum probably due to enhanced vasopressin production and secretion.
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Wang C, Kawakami-Mori F, Kang L, Ayuzawa N, Ogura S, Koid SS, Reheman L, Yeerbolati A, Liu B, Yatomi Y, Chen X, Fujita T, Shimosawa T. Low-dose L-NAME induces salt sensitivity associated with sustained increased blood volume and sodium-chloride cotransporter activity in rodents. Kidney Int 2020; 98:1242-1252. [PMID: 32592815 DOI: 10.1016/j.kint.2020.05.050] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 05/18/2020] [Accepted: 05/21/2020] [Indexed: 12/01/2022]
Abstract
To investigate the cause of salt sensitivity in a normotensive animal model, we treated rats with a low-dose of the nitric oxide synthase inhibitor, L-NAME, that does not elevate blood pressure per se or induce kidney fibrosis. A high salt diet increased the circulating blood volume both in L-NAME-treated and nontreated animals for the first 24 hours. Thereafter, the blood volume increase persisted only in the L-NAME-treated rats. Blood pressure was higher in the L-NAME-treated group from the start of high salt diet exposure. Within the first 24 hours of salt loading, the L-NAME treated animals failed to show vasodilation and maintained high systemic vascular resistance in response to blood volume expansion. After four weeks on the high salt diet, the slope of the pressure-natriuresis curve was blunted in the L-NAME-treated group. An increase in natriuresis was observed after treatment with hydrochlorothiazide, but not amiloride, a change observed in parallel with increased phosphorylated sodium-chloride cotransporter (NCC). In contrast, a change in blood pressure was not observed in L-NAME-treated NCC-deficient mice fed a high salt diet. Moreover, direct L-NAME-induced NCC activation was demonstrated in cells of the mouse distal convoluted tubule. The vasodilatator, sodium nitroprusside, downregulated phosphorylated NCC expression. The effect of L-NAME on phosphorylated NCC was blocked by both the SPAK inhibitor STOCK2S-26016 and the superoxide dismutase mimetic TEMPO which also attenuated salt-induced hypertension. These results suggest that the initiation of salt sensitivity in normotensive rodents could be due to hyporeactivity of the vasculature and that maintaining blood pressure could result in a high circulating volume due to inappropriate NCC activity in the low-dose L-NAME model. Thus, even slightly impaired nitric oxide production may be important in salt sensitivity regulation in healthy rodents.
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Affiliation(s)
- Conghui Wang
- Department of Nephrology, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China; Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Fumiko Kawakami-Mori
- Department of Clinical Epigenetics, Research Center for Advancing Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Lei Kang
- Department of Nuclear Medicine, Peking University First Hospital, Beijing, China
| | - Nobuhiro Ayuzawa
- Department of Clinical Epigenetics, Research Center for Advancing Science and Technology, The University of Tokyo, Tokyo, Japan
| | - Sayoko Ogura
- Department of Pathology and Microbiology, Division of Laboratory Medicine, School of Medicine, Nihon University, Tokyo, Japan
| | - Suang Suang Koid
- Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan; Department of Clinical Laboratory, School of Medicine, International University of Health and Welfare, Chiba, Japan
| | - Latapati Reheman
- Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Alimila Yeerbolati
- Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Beibei Liu
- Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Yutaka Yatomi
- Department of Clinical Laboratory, School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Xiangmei Chen
- Department of Nephrology, Chinese PLA Institute of Nephrology, State Key Laboratory of Kidney Diseases, National Clinical Research Center for Kidney Diseases, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
| | - Toshiro Fujita
- Department of Clinical Epigenetics, Research Center for Advancing Science and Technology, The University of Tokyo, Tokyo, Japan; CREST, Japan Science and Technology Agency, Tokyo, Japan
| | - Tatsuo Shimosawa
- Department of Clinical Laboratory, School of Medicine, International University of Health and Welfare, Chiba, Japan; CREST, Japan Science and Technology Agency, Tokyo, Japan.
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Tantisattamo E, Molnar MZ, Ho BT, Reddy UG, Dafoe DC, Ichii H, Ferrey AJ, Hanna RM, Kalantar-Zadeh K, Amin A. Approach and Management of Hypertension After Kidney Transplantation. Front Med (Lausanne) 2020; 7:229. [PMID: 32613001 PMCID: PMC7310511 DOI: 10.3389/fmed.2020.00229] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 05/04/2020] [Indexed: 12/14/2022] Open
Abstract
Hypertension is one of the most common cardiovascular co-morbidities after successful kidney transplantation. It commonly occurs in patients with other metabolic diseases, such as diabetes mellitus, hyperlipidemia, and obesity. The pathogenesis of post-transplant hypertension is complex and is a result of the interplay between immunological and non-immunological factors. Post-transplant hypertension can be divided into immediate, early, and late post-transplant periods. This classification can help clinicians determine the etiology and provide the appropriate management for these complex patients. Volume overload from intravenous fluid administration is common during the immediate post-transplant period and commonly contributes to hypertension seen early after transplantation. Immunosuppressive medications and donor kidneys are associated with post-transplant hypertension occurring at any time point after transplantation. Transplant renal artery stenosis (TRAS) and obstructive sleep apnea (OSA) are recognized but common and treatable causes of resistant hypertension post-transplantation. During late post-transplant period, chronic renal allograft dysfunction becomes an additional cause of hypertension. As these patients develop more substantial chronic kidney disease affecting their allografts, fibroblast growth factor 23 (FGF23) increases and is associated with increased cardiovascular and all-cause mortality in kidney transplant recipients. The exact relationship between increased FGF23 and post-transplant hypertension remains poorly understood. Blood pressure (BP) targets and management involve both non-pharmacologic and pharmacologic treatment and should be individualized. Until strong evidence in the kidney transplant population exists, a BP of <130/80 mmHg is a reasonable target. Similar to complete renal denervation in non-transplant patients, bilateral native nephrectomy is another treatment option for resistant post-transplant hypertension. Native renal denervation offers promising outcomes for controlling resistant hypertension with no significant procedure-related complications. This review addresses the epidemiology, pathogenesis, and specific etiologies of post-transplant hypertension including TRAS, calcineurin inhibitor effects, OSA, and failed native kidney. The cardiovascular and survival outcomes related to post-transplant hypertension and the utility of 24-h blood pressure monitoring will be briefly discussed. Antihypertensive medications and their mechanism of actions relevant to kidney transplantation will be highlighted. A summary of guidelines from different professional societies for BP targets and antihypertensive medications as well as non-pharmacological interventions, including bilateral native nephrectomy and native renal denervation, will be reviewed.
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Affiliation(s)
- Ekamol Tantisattamo
- Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine School of Medicine, Orange, CA, United States.,Nephrology Section, Department of Medicine, Tibor Rubin Veterans Affairs Medical Center, VA Long Beach Healthcare System, Long Beach, CA, United States.,Section of Nephrology, Department of Internal Medicine, Multi-Organ Transplant Center, William Beaumont Hospital, Oakland University William Beaumont School of Medicine, Royal Oak, MI, United States
| | - Miklos Z Molnar
- Division of Nephrology, University of Tennessee Health Science Center, Memphis, TN, United States.,Methodist University Hospital Transplant Institute, Memphis, TN, United States.,Division of Transplant Surgery, Department of Surgery, University of Tennessee Health Science Center, Memphis, TN, United States
| | - Bing T Ho
- Division of Nephrology and Hypertension, Department of Medicine, Comprehensive Transplant Center, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
| | - Uttam G Reddy
- Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine School of Medicine, Orange, CA, United States.,Nephrology Section, Department of Medicine, Tibor Rubin Veterans Affairs Medical Center, VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Donald C Dafoe
- Division of Transplantation, Department of Surgery, University of California Irvine School of Medicine, Orange, CA, United States
| | - Hirohito Ichii
- Division of Transplantation, Department of Surgery, University of California Irvine School of Medicine, Orange, CA, United States
| | - Antoney J Ferrey
- Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine School of Medicine, Orange, CA, United States.,Nephrology Section, Department of Medicine, Tibor Rubin Veterans Affairs Medical Center, VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Ramy M Hanna
- Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine School of Medicine, Orange, CA, United States
| | - Kamyar Kalantar-Zadeh
- Division of Nephrology, Hypertension and Kidney Transplantation, Department of Medicine, Harold Simmons Center for Kidney Disease Research and Epidemiology, University of California Irvine School of Medicine, Orange, CA, United States.,Nephrology Section, Department of Medicine, Tibor Rubin Veterans Affairs Medical Center, VA Long Beach Healthcare System, Long Beach, CA, United States
| | - Alpesh Amin
- Department of Medicine, University of California Irvine School of Medicine, Orange, CA, United States
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57
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Furusho T, Uchida S, Sohara E. The WNK signaling pathway and salt-sensitive hypertension. Hypertens Res 2020; 43:733-743. [PMID: 32286498 DOI: 10.1038/s41440-020-0437-x] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2020] [Revised: 03/11/2020] [Accepted: 03/11/2020] [Indexed: 12/19/2022]
Abstract
The distal nephron of the kidney has a central role in sodium and fluid homeostasis, and disruption of this homeostasis due to mutations of with-no-lysine kinase 1 (WNK1), WNK4, Kelch-like 3 (KLHL3), or Cullin 3 (CUL3) causes pseudohypoaldosteronism type II (PHAII), an inherited hypertensive disease. WNK1 and WNK4 activate the NaCl cotransporter (NCC) at the distal convoluted tubule through oxidative stress-responsive gene 1 (OSR1)/Ste20-related proline-alanine-rich kinase (SPAK), constituting the WNK-OSR1/SPAK-NCC phosphorylation cascade. The level of WNK protein is regulated through degradation by the CUL3-KLHL3 E3 ligase complex. In the normal state, the activity of WNK signaling in the kidney is physiologically regulated by sodium intake to maintain sodium homeostasis in the body. In patients with PHAII, however, because of the defective degradation of WNK kinases, NCC is constitutively active and not properly suppressed by a high salt diet, leading to abnormally increased salt reabsorption and salt-sensitive hypertension. Importantly, recent studies have demonstrated that potassium intake, insulin, and TNFα are also physiological regulators of WNK signaling, suggesting that they contribute to the salt-sensitive hypertension associated with a low potassium diet, metabolic syndrome, and chronic kidney disease, respectively. Moreover, emerging evidence suggests that WNK signaling also has some unique roles in metabolic, cardiovascular, and immunological organs. Here, we review the recent literature and discuss the molecular mechanisms of the WNK signaling pathway and its potential as a therapeutic target.
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Affiliation(s)
- Taisuke Furusho
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shinichi Uchida
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Eisei Sohara
- Department of Nephrology, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan.
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Yoshimura R, Yamamoto R, Shinzawa M, Tomi R, Ozaki S, Fujii Y, Ito T, Tanabe K, Moriguchi Y, Isaka Y, Moriyama T. Drinking frequency modifies an association between salt intake and blood pressure: A cohort study. J Clin Hypertens (Greenwich) 2020; 22:649-655. [PMID: 32175653 DOI: 10.1111/jch.13844] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2020] [Revised: 02/24/2020] [Accepted: 02/27/2020] [Indexed: 11/28/2022]
Abstract
Salt sensitivity is one of the crucial risk factors of hypertension. The aim of the present prospective cohort study was to assess the clinical impact of alcohol drinking on an association between salt intake and blood pressure. The present study included 451 employees at a pharmaceutical company in Japan who underwent annual health checkups in both 2017 and 2018. The main exposure of interest was self-reported drinking frequency at their first checkups: rarely, occasionally, and daily. To assess the association between the change of salt intake estimated from single-spot urine specimens and that of blood pressure, the differences in systolic/diastolic blood pressure and salt intake between 2017 and 2018 were calculated for each subject. Multivariable-adjusted linear regression models adjusting for clinically relevant factors clarified a drinking frequency-dependent association between Δsalt intake and Δsystolic blood pressure (per 1 g/d of Δsalt intake adjusted β [95% confidence interval] 0.19 [-0.73, 1.12], 0.84 [0.14, 1.53], and 1.78 [0.86, 2.69] in rare, occasional, and daily drinkers). A similar association between Δsalt intake and Δdiastolic blood pressure was also observed (-0.24 [-1.02, 0.54], 0.67 (0.18, 1.16), 0.95 [0.38, 1.51], in rare, occasional, and daily drinkers). The interactions between drinking frequency and Δsalt intake were found to be statistically significant (P for interaction = .028 and .006 for ∆systolic blood pressure and ∆diastolic blood pressure, respectively). The present study identified enhanced salt sensitivity in the subjects who drink at a higher frequency, suggesting that the reduction in alcohol consumption may improve salt sensitivity in higher frequency drinkers.
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Affiliation(s)
- Ryuichi Yoshimura
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan.,Division of Nephrology, Shimane University Hospital, Izumo, Japan
| | - Ryohei Yamamoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan.,Health and Counseling Center, Osaka University, Toyonaka, Japan.,Heatlth Promotion and Regulation, Department of Health Promotion Medicine, Osaka University Graduate School of Medicine, Toyonaka, Japan
| | - Maki Shinzawa
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Ryohei Tomi
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Shingo Ozaki
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshiyuki Fujii
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Takafumi Ito
- Division of Nephrology, Shimane University Hospital, Izumo, Japan
| | - Kazuaki Tanabe
- Department of Internal Medicine IV, Shimane University Faculty of Medicine, Izumo, Japan
| | | | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Toshiki Moriyama
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan.,Health and Counseling Center, Osaka University, Toyonaka, Japan.,Heatlth Promotion and Regulation, Department of Health Promotion Medicine, Osaka University Graduate School of Medicine, Toyonaka, Japan
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Mouton AJ, Li X, Hall ME, Hall JE. Obesity, Hypertension, and Cardiac Dysfunction: Novel Roles of Immunometabolism in Macrophage Activation and Inflammation. Circ Res 2020; 126:789-806. [PMID: 32163341 PMCID: PMC7255054 DOI: 10.1161/circresaha.119.312321] [Citation(s) in RCA: 251] [Impact Index Per Article: 62.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Obesity and hypertension, which often coexist, are major risk factors for heart failure and are characterized by chronic, low-grade inflammation, which promotes adverse cardiac remodeling. While macrophages play a key role in cardiac remodeling, dysregulation of macrophage polarization between the proinflammatory M1 and anti-inflammatory M2 phenotypes promotes excessive inflammation and cardiac injury. Metabolic shifting between glycolysis and mitochondrial oxidative phosphorylation has been implicated in macrophage polarization. M1 macrophages primarily rely on glycolysis, whereas M2 macrophages rely on the tricarboxylic acid cycle and oxidative phosphorylation; thus, factors that affect macrophage metabolism may disrupt M1/M2 homeostasis and exacerbate inflammation. The mechanisms by which obesity and hypertension may synergistically induce macrophage metabolic dysfunction, particularly during cardiac remodeling, are not fully understood. We propose that obesity and hypertension induce M1 macrophage polarization via mechanisms that directly target macrophage metabolism, including changes in circulating glucose and fatty acid substrates, lipotoxicity, and tissue hypoxia. We discuss canonical and novel proinflammatory roles of macrophages during obesity-hypertension-induced cardiac injury, including diastolic dysfunction and impaired calcium handling. Finally, we discuss the current status of potential therapies to target macrophage metabolism during heart failure, including antidiabetic therapies, anti-inflammatory therapies, and novel immunometabolic agents.
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Affiliation(s)
- Alan J. Mouton
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
| | - Xuan Li
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
| | - Michael E. Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
- Department of Medicine, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
| | - John E. Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
- Mississippi Center for Obesity Research, University of Mississippi Medical Center, 2500 North State Street; Jackson, MS, 39216-4505
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60
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Hall JE, do Carmo JM, da Silva AA, Wang Z, Hall ME. Obesity, kidney dysfunction and hypertension: mechanistic links. Nat Rev Nephrol 2020; 15:367-385. [PMID: 31015582 DOI: 10.1038/s41581-019-0145-4] [Citation(s) in RCA: 298] [Impact Index Per Article: 74.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Excessive adiposity raises blood pressure and accounts for 65-75% of primary hypertension, which is a major driver of cardiovascular and kidney diseases. In obesity, abnormal kidney function and associated increases in tubular sodium reabsorption initiate hypertension, which is often mild before the development of target organ injury. Factors that contribute to increased sodium reabsorption in obesity include kidney compression by visceral, perirenal and renal sinus fat; increased renal sympathetic nerve activity (RSNA); increased levels of anti-natriuretic hormones, such as angiotensin II and aldosterone; and adipokines, particularly leptin. The renal and neurohormonal pathways of obesity and hypertension are intertwined. For example, leptin increases RSNA by stimulating the central nervous system proopiomelanocortin-melanocortin 4 receptor pathway, and kidney compression and RSNA contribute to renin-angiotensin-aldosterone system activation. Glucocorticoids and/or oxidative stress may also contribute to mineralocorticoid receptor activation in obesity. Prolonged obesity and progressive renal injury often lead to the development of treatment-resistant hypertension. Patient management therefore often requires multiple antihypertensive drugs and concurrent treatment of dyslipidaemia, insulin resistance, diabetes and inflammation. If more effective strategies for the prevention and control of obesity are not developed, cardiorenal, metabolic and other obesity-associated diseases could overwhelm health-care systems in the future.
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Affiliation(s)
- John E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA. .,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA.
| | - Jussara M do Carmo
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Alexandre A da Silva
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Zhen Wang
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA
| | - Michael E Hall
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, USA.,Mississippi Center for Obesity Research, University of Mississippi Medical Center, Jackson, MS, USA.,Department of Medicine, University of Mississippi Medical Center, Jackson, MS, USA
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61
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Brands MW. Unifying Approach for Interpreting the Physiological Effect of High Salt Intake. Hypertension 2020; 75:620-622. [PMID: 31957523 DOI: 10.1161/hypertensionaha.119.14030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Michael W Brands
- From the Department of Physiology, Medical College of Georgia, Augusta
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Abstract
Despite availability of effective drugs for hypertension therapy, significant numbers of hypertensive patients fail to achieve recommended blood pressure levels on ≥3 antihypertensive drugs of different classes. These individuals have a high prevalence of adverse cardiovascular events and are defined as having resistant hypertension (RHT) although nonadherence to prescribed antihypertensive medications is common in patients with apparent RHT. Furthermore, apparent and true RHT often display increased sympathetic activity. Based on these findings, technology was developed to treat RHT by suppressing sympathetic activity with electrical stimulation of the carotid baroreflex and catheter-based renal denervation (RDN). Over the last 15 years, experimental and clinical studies have provided better understanding of the physiological mechanisms that account for blood pressure lowering with baroreflex activation and RDN and, in so doing, have provided insight into which patients in this heterogeneous hypertensive population are most likely to respond favorably to these device-based therapies. Experimental studies have also played a role in modifying device technology after early clinical trials failed to meet key endpoints for safety and efficacy. At the same time, these studies have exposed potential differences between baroreflex activation and RDN and common challenges that will likely impact antihypertensive treatment and clinical outcomes in patients with RHT. In this review, we emphasize physiological studies that provide mechanistic insights into blood pressure lowering with baroreflex activation and RDN in the context of progression of clinical studies, which are now at a critical point in determining their fate in RHT management.
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Affiliation(s)
- Thomas E Lohmeier
- From the Department of Physiology and Biophysics (T.E.L., J.E.H.), University of Mississippi Medical Center, Jackson
| | - John E Hall
- From the Department of Physiology and Biophysics (T.E.L., J.E.H.), University of Mississippi Medical Center, Jackson.,Mississippi Center for Obesity Research (J.E.H.), University of Mississippi Medical Center, Jackson
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63
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Rinschen MM, Palygin O, Guijas C, Palermo A, Palacio-Escat N, Domingo-Almenara X, Montenegro-Burke R, Saez-Rodriguez J, Staruschenko A, Siuzdak G. Metabolic rewiring of the hypertensive kidney. Sci Signal 2019; 12:12/611/eaax9760. [PMID: 31822592 DOI: 10.1126/scisignal.aax9760] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hypertension is a persistent epidemic across the developed world that is closely associated with kidney disease. Here, we applied a metabolomic, phosphoproteomic, and proteomic strategy to analyze the effect of hypertensive insults on kidneys. Our data revealed the metabolic aspects of hypertension-induced glomerular sclerosis, including lipid breakdown at early disease stages and activation of anaplerotic pathways to regenerate energy equivalents to counter stress. For example, branched-chain amino acids and proline, required for collagen synthesis, were depleted in glomeruli at early time points. Furthermore, indicators of metabolic stress were reflected by low amounts of ATP and NADH and an increased abundance of oxidized lipids derived from lipid breakdown. These processes were specific to kidney glomeruli where metabolic signaling occurred through mTOR and AMPK signaling. Quantitative phosphoproteomics combined with computational modeling suggested that these processes controlled key molecules in glomeruli and specifically podocytes, including cytoskeletal components and GTP-binding proteins, which would be expected to compete for decreasing amounts of GTP at early time points. As a result, glomeruli showed increased expression of metabolic enzymes of central carbon metabolism, amino acid degradation, and lipid oxidation, findings observed in previously published studies from other disease models and patients with glomerular damage. Overall, multilayered omics provides an overview of hypertensive kidney damage and suggests that metabolic or dietary interventions could prevent and treat glomerular disease and hypertension-induced nephropathy.
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Affiliation(s)
- Markus M Rinschen
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA.,Department II of Internal Medicine and Center for Molecular Medicine, University of Cologne, Cologne 50931, Germany
| | - Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Carlos Guijas
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA
| | - Amelia Palermo
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA
| | - Nicolas Palacio-Escat
- COMBINE-Joint Research Center for Computational Biomedicine RWTH Aachen University, Aachen 52074, Germany.,Institute of Computational Biomedicine, Bioquant, Faculty of Medicine and Heidelberg University Hospital, Heidelberg University, Heidelberg 69120, Germany.,Faculty of Biosciences, University of Heidelberg, Heidelberg 69120, Germany
| | - Xavier Domingo-Almenara
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA
| | - Rafael Montenegro-Burke
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA
| | - Julio Saez-Rodriguez
- COMBINE-Joint Research Center for Computational Biomedicine RWTH Aachen University, Aachen 52074, Germany.,Institute of Computational Biomedicine, Bioquant, Faculty of Medicine and Heidelberg University Hospital, Heidelberg University, Heidelberg 69120, Germany.,Molecular Medicine Partnership Unit (MMPU), European Molecular Biology Laboratory and Heidelberg University, Heidelberg 69120, Germany
| | - Alexander Staruschenko
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA. .,Clement J. Zablocki VA Medical Center, Milwaukee, WI 53295, USA
| | - Gary Siuzdak
- Center for Metabolomics and Mass Spectrometry, The Scripps Research Institute, La Jolla, CA 92122, USA.
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64
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Kramer H. Diet and Chronic Kidney Disease. Adv Nutr 2019; 10:S367-S379. [PMID: 31728497 PMCID: PMC6855949 DOI: 10.1093/advances/nmz011] [Citation(s) in RCA: 60] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 12/04/2018] [Accepted: 01/07/2019] [Indexed: 02/07/2023] Open
Abstract
Kidney disease affects almost 15% of the US population, and prevalence is anticipated to grow as the population ages and the obesity epidemic continues due to Western dietary practices. The densely caloric Western diet, characterized by high animal protein and low fruit and vegetable content, has fueled the growth of chronic diseases, including chronic kidney disease. The glomerulus or filtering unit of the kidney is very susceptible to barotrauma, and diets high in animal protein impede the glomerulus' ability to protect itself from hemodynamic injury. High animal protein intake combined with low intake of fruits and vegetables also leads to a high net endogenous acid production requiring augmentation of ammonium excretion in order to prevent acidosis. This higher workload of the kidney to maintain a normal serum bicarbonate level may further exacerbate kidney disease progression. This article reviews the potential mechanisms whereby several key characteristics of the typical Western diet may impact kidney disease incidence and progression. Reducing animal protein intake and egg yolk and increasing intake of fruits and vegetables and fiber may prevent or delay end-stage renal disease, but few clinical trials have examined vegetarian diets for management of chronic kidney disease. More research is needed to determine optimal dietary patterns for the prevention of kidney disease and its progression.
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Affiliation(s)
- Holly Kramer
- Department of Public Health Sciences and Medicine
- Division of Nephrology and Hypertension, Loyola University, Chicago, IL
- Address correspondence to HK (e-mail: )
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65
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Clemmer JS, Pruett WA, Hester RL, Lohmeier TE. Preeminent role of the cardiorenal axis in the antihypertensive response to an arteriovenous fistula: an in silico analysis. Am J Physiol Heart Circ Physiol 2019; 317:H1002-H1012. [PMID: 31469293 DOI: 10.1152/ajpheart.00354.2019] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Percutaneous creation of a small central arteriovenous (AV) fistula is currently being evaluated for the treatment of uncontrolled hypertension (HT). Although the mechanisms that contribute to the antihypertensive effects of the fistula are unclear, investigators have speculated that chronic blood pressure (BP) lowering may be due to 1) reduced total peripheral resistance (TPR), 2) increased secretion of atrial natriuretic peptide (ANP), and/or 3) suppression of renal sympathetic nerve activity (RSNA). We used an established integrative mathematical model of human physiology to investigate these possibilities from baseline conditions that mimic sympathetic overactivity and impaired renal function in patients with resistant HT. After a small fistula was stimulated, there were sustained increases in cardiac output, atrial pressures, and plasma ANP concentration (3-fold), without suppression of RSNA; at 8 wk, BP was reduced 14 mmHg along with a 32% fall in TPR. In contrast, when this simulation was repeated while clamping ANP at baseline BP decreased only 4 mmHg, despite a comparable fall in TPR. Furthermore, when chronic resetting of atrial mechanoreceptors was prevented during the fistula, RSNA decreased 7%, and along with the same threefold increase in ANP, BP fell 19 mmHg. This exaggerated fall in BP occurred with a similar decrease in TPR when compared with the above simulations. These findings suggest that ANP, but not TPR, is a key determinant of long-term BP lowering after the creation of an AV fistula and support a contribution of suppressed RSNA if resetting of the atrial-renal reflex is truly incomplete.NEW & NOTEWORTHY The mechanisms that contribute to the antihypertensive effects of a small arteriovenous (AV) fistula comparable to the size used by the ROX coupler currently in clinical trials are unclear and not readily testable in clinical or experimental studies. The integrative mathematical model of human physiology used in the current study provides a tool for understanding key causal relationships that account for blood pressure (BP) lowering and for testing competing hypotheses. The findings from the simulations suggest that after creation of a small AV fistula increased ANP secretion plays a critical role in mediating long-term reductions in BP. Measurement of natriuretic peptide levels in hypertensive patients implanted with the ROX coupler would provide one critical test of this hypothesis.
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Affiliation(s)
- John S Clemmer
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - W Andrew Pruett
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert L Hester
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi.,John D. Bower School of Population Health, University of Mississippi Medical Center, Jackson, Mississippi
| | - Thomas E Lohmeier
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi
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66
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Yan Y, Wang J, Chaudhry MA, Nie Y, Sun S, Carmon J, Shah PT, Bai F, Pratt R, Brickman C, Sodhi K, Kim JH, Pierre S, Malhotra D, Rankin GO, Xie ZJ, Shapiro JI, Liu J. Metabolic Syndrome and Salt-Sensitive Hypertension in Polygenic Obese TALLYHO/JngJ Mice: Role of Na/K-ATPase Signaling. Int J Mol Sci 2019; 20:ijms20143495. [PMID: 31315267 PMCID: PMC6678942 DOI: 10.3390/ijms20143495] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2019] [Revised: 07/06/2019] [Accepted: 07/13/2019] [Indexed: 12/12/2022] Open
Abstract
We have demonstrated that Na/K-ATPase acts as a receptor for reactive oxygen species (ROS), regulating renal Na+ handling and blood pressure. TALLYHO/JngJ (TH) mice are believed to mimic the state of obesity in humans with a polygenic background of type 2 diabetes. This present work is to investigate the role of Na/K-ATPase signaling in TH mice, focusing on susceptibility to hypertension due to chronic excess salt ingestion. Age-matched male TH and the control C57BL/6J (B6) mice were fed either normal diet or high salt diet (HS: 2, 4, and 8% NaCl) to construct the renal function curve. Na/K-ATPase signaling including c-Src and ERK1/2 phosphorylation, as well as protein carbonylation (a commonly used marker for enhanced ROS production), were assessed in the kidney cortex tissues by Western blot. Urinary and plasma Na+ levels were measured by flame photometry. When compared to B6 mice, TH mice developed salt-sensitive hypertension and responded to a high salt diet with a significant rise in systolic blood pressure indicative of a blunted pressure-natriuresis relationship. These findings were evidenced by a decrease in total and fractional Na+ excretion and a right-shifted renal function curve with a reduced slope. This salt-sensitive hypertension correlated with changes in the Na/K-ATPase signaling. Specifically, Na/K-ATPase signaling was not able to be stimulated by HS due to the activated baseline protein carbonylation, phosphorylation of c-Src and ERK1/2. These findings support the emerging view that Na/K-ATPase signaling contributes to metabolic disease and suggest that malfunction of the Na/K-ATPase signaling may promote the development of salt-sensitive hypertension in obesity. The increased basal level of renal Na/K-ATPase-dependent redox signaling may be responsible for the development of salt-sensitive hypertension in polygenic obese TH mice.
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Affiliation(s)
- Yanling Yan
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Jiayan Wang
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Muhammad A Chaudhry
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Ying Nie
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Shuyan Sun
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
- Hebei Medical University, Shijiazhuang 50017, China
| | - Jazmin Carmon
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Preeya T Shah
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Fang Bai
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Rebecca Pratt
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Cameron Brickman
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Komal Sodhi
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Jung Han Kim
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Sandrine Pierre
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Deepak Malhotra
- Department of Medicine, The University of Toledo College of Medicine and Life Sciences, Toledo, OH 43614, USA
| | - Gary O Rankin
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Zi-Jian Xie
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Joseph I Shapiro
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
| | - Jiang Liu
- Departments of Clinical & Translational Sciences, Biomedical Sciences, and Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA
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67
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Assersen KB, Høilund‐Carlsen PF, Olsen MH, Greve SV, Gam‐Hadberg JC, Braad P, Damkjaer M, Bie P. The exaggerated natriuresis of essential hypertension occurs independently of changes in renal medullary blood flow. Acta Physiol (Oxf) 2019; 226:e13266. [PMID: 30770642 DOI: 10.1111/apha.13266] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 02/10/2019] [Accepted: 02/12/2019] [Indexed: 01/20/2023]
Abstract
AIMS In patients with essential hypertension, abnormal renal sodium handling includes exaggerated natriuresis in response to extracellular volume expansion. We tested the hypothesis that exaggerated natriuresis is associated with increases in medullary and/or cortical renal blood flow. METHODS Patients with mild essential hypertension, but no signs of end organ damage, and control subjects were studied after 4 days of dietary standardization (<60 mmol Na+ day-1 ) preceded in patients by a 14-day drug washout period. On the study day, subjects received a 4-hour intravenous volume expansion with saline (2.1% of body mass). Renal medullary and cortical blood flows were measured by PET scanning using H2 15 O as tracer; anatomical regions of interest were defined by contrast-enhanced CT scanning. RESULTS In patients, arterial blood pressure increased during volume expansion (107 ± 2-114 ± 3 mm Hg, P < 0.05) in contrast to the control group (92 ± 2-92 ± 2 mm Hg). Renal sodium excretion increased more in patients than in controls (+133 ± 31 µmol min-1 vs +61 ± 14 µmol min-1 , respectively, P < 0.05) confirming exaggerated natriuresis. During volume expansion, renal medullary blood flow did not change significantly in patients (2.8 ± 0.4-2.5 ± 0.5 mL (g tissue)-1 min-1 ) or in controls (3.2 ± 0.3-3.1 ± 0.2 mL (g tissue)-1 min-1 ). In control subjects, renal cortical blood flow fell during volume expansion (4.1 ± 0.3-3.7 ± 0.2 mL (g tissue)-1 min-1 , P < 0.05) in contrast to patients in which deviations remained insignificant. CONCLUSION Exaggerated natriuresis, a hallmark of essential hypertension, is not mediated by increases in regional, renal blood flow.
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Affiliation(s)
- Kasper B. Assersen
- Cardiovascular and Renal Research, Institute of Molecular Medicine University of Southern Denmark Odense Denmark
| | | | | | - Sara V. Greve
- Department of Endocrinology Odense University Hospital Svendborg Denmark
| | | | - Poul‐Erik Braad
- Department of Nuclear Medicine Odense University Hospital Odense Denmark
| | - Mads Damkjaer
- Hans Christian Andersen Children's Hospital Odense University Hospital Odense Denmark
| | - Peter Bie
- Cardiovascular and Renal Research, Institute of Molecular Medicine University of Southern Denmark Odense Denmark
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68
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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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69
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Kurtz TW, DiCarlo SE, Pravenec M, Ježek F, Šilar J, Kofránek J, Morris RC. Testing Computer Models Predicting Human Responses to a High-Salt Diet. Hypertension 2019; 72:1407-1416. [PMID: 30571226 DOI: 10.1161/hypertensionaha.118.11552] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Recently, mathematical models of human integrative physiology, derived from Guyton's classic 1972 model of the circulation, have been used to investigate potential mechanistic abnormalities mediating salt sensitivity and salt-induced hypertension. We performed validation testing of 2 of the most evolved derivatives of Guyton's 1972 model, Quantitative Cardiovascular Physiology-2005 and HumMod-3.0.4, to determine whether the models accurately predict sodium balance and hemodynamic responses of normal subjects to increases in salt intake within the real-life range of salt intake in humans. Neither model, nor the 1972 Guyton model, accurately predicts the usual changes in sodium balance, cardiac output, and systemic vascular resistance that normally occur in response to clinically realistic increases in salt intake. Furthermore, although both contemporary models are extensions of the 1972 Guyton model, testing revealed major inconsistencies between model predictions with respect to sodium balance and hemodynamic responses of normal subjects to short-term and long-term salt loading. These results demonstrate significant limitations with the hypotheses inherent in the Guyton models regarding the usual regulation of sodium balance, cardiac output, and vascular resistance in response to increased salt intake in normal salt-resistant humans. Accurate understanding of the normal responses to salt loading is a prerequisite for accurately establishing abnormal responses to salt loading. Accordingly, the present results raise concerns about the interpretation of studies of salt sensitivity with the various Guyton models. These findings indicate a need for continuing development of alternative models that incorporate mechanistic concepts of blood pressure regulation fundamentally different from those in the 1972 Guyton model and its contemporary derivatives.
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Affiliation(s)
- Theodore W Kurtz
- From the Department of Laboratory Medicine (T.W.K.), School of Medicine, University of California, San Francisco
| | - Stephen E DiCarlo
- Department of Physiology, College of Osteopathic Medicine, Michigan State University, East Lansing (S.E.D.)
| | - Michal Pravenec
- Institute of Physiology of the Czech Academy of Sciences, Prague (M.P.)
| | - Filip Ježek
- Department of Cybernetics, Czech Technical University in Prague (F.J.).,Department of Pathophysiology, 1st Faculty of Medicine, Charles University, Prague (F.J., J.S., J.K.)
| | - Jan Šilar
- Department of Pathophysiology, 1st Faculty of Medicine, Charles University, Prague (F.J., J.S., J.K.)
| | - Jiří Kofránek
- Department of Pathophysiology, 1st Faculty of Medicine, Charles University, Prague (F.J., J.S., J.K.)
| | - R Curtis Morris
- Department of Medicine (R.C.M.), School of Medicine, University of California, San Francisco
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70
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Morris RC, Pravenec M, Šilhavý J, DiCarlo SE, Kurtz TW. Small Amounts of Inorganic Nitrate or Beetroot Provide Substantial Protection From Salt-Induced Increases in Blood Pressure. Hypertension 2019; 73:1042-1048. [PMID: 30917704 PMCID: PMC6458074 DOI: 10.1161/hypertensionaha.118.12234] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
To reduce the risk of salt-induced hypertension, medical authorities have emphasized dietary guidelines promoting high intakes of potassium and low intakes of salt that provide molar ratios of potassium to salt of ≥1:1. However, during the past several decades, relatively few people have changed their eating habits sufficiently to reach the recommended dietary goals for salt and potassium. Thus, new strategies that reduce the risk of salt-induced hypertension without requiring major changes in dietary habits would be of considerable medical interest. In the current studies in a widely used model of salt-induced hypertension, the Dahl salt-sensitive rat, we found that supplemental dietary sodium nitrate confers substantial protection from initiation of salt-induced hypertension when the molar ratio of added nitrate to added salt is only ≈1:170. Provision of a low molar ratio of added nitrate to added salt of ≈1:110 by supplementing the diet with beetroot also conferred substantial protection against salt-induced increases in blood pressure. The results suggest that on a molar basis and a weight basis, dietary nitrate may be ≈100× more potent than dietary potassium with respect to providing substantial resistance to the pressor effects of increased salt intake. Given that leafy green and root vegetables contain large amounts of inorganic nitrate, these findings raise the possibility that fortification of salty food products with small amounts of a nitrate-rich vegetable concentrate may provide a simple method for reducing risk for salt-induced hypertension.
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Affiliation(s)
- R. Curtis Morris
- Department of Medicine, University of California, San Francisco, San Francisco, USA, 94143
| | - Michal Pravenec
- Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic, 14220
| | - Jan Šilhavý
- Institute of Physiology of the Czech Academy of Sciences, Prague, Czech Republic, 14220
| | - Stephen E. DiCarlo
- Department of Physiology, College of Osteopathic Medicine, Michigan State University, East Lansing, USA, 48824
| | - Theodore W. Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, USA, 94107-0134
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71
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Abstract
PURPOSE OF REVIEW Excess sodium from dietary salt (NaCl) is linked to elevations in blood pressure (BP). However, salt sensitivity of BP varies widely between individuals and there are data suggesting that salt adversely affects target organs, irrespective of BP. RECENT FINDINGS High dietary salt has been shown to adversely affect the vasculature, heart, kidneys, skin, brain, and bone. Common mediators of the target organ dysfunction include heightened inflammation and oxidative stress. These physiological alterations may contribute to disease development over time. Despite the adverse effects of salt on BP and several organ systems, there is controversy surrounding lower salt intakes and cardiovascular outcomes. Our goal here is to review the physiology contributing to BP-independent effects of salt and address the controversy around lower salt intakes and cardiovascular outcomes. We will also address the importance of background diet in modulating the effects of dietary salt.
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Affiliation(s)
- Austin T Robinson
- Department of Kinesiology and Applied Physiology, University of Delaware, 540 South College Avenue, 201M, Newark, DE, 19713, USA
| | - David G Edwards
- Department of Kinesiology and Applied Physiology, University of Delaware, 540 South College Avenue, 201M, Newark, DE, 19713, USA
| | - William B Farquhar
- Department of Kinesiology and Applied Physiology, University of Delaware, 540 South College Avenue, 201M, Newark, DE, 19713, USA.
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72
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Abdelhedi O, Khemakhem H, Nasri R, Jridi M, Mora L, Ben Amor I, Jamoussi K, Toldrá F, Gargouri J, Nasri M. Assessment of Cholesterol, Glycemia Control and Short- and Long-Term Antihypertensive Effects of Smooth Hound Viscera Peptides in High-Salt and Fructose Diet-Fed Wistar Rats. Mar Drugs 2019; 17:E194. [PMID: 30934709 PMCID: PMC6520678 DOI: 10.3390/md17040194] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2018] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 12/22/2022] Open
Abstract
In this study, the antihypertensive activity of Purafect®-smooth hound viscera protein hydrolysate (VPH) and its peptide fraction with molecular weight (MW) below 1 kDa (VPH-I) was investigated. In addition, the lipase inhibitory activity, as well the anticoagulant potential, in vitro, were assessed. The antihypertensive effects of VPH and VPH-I were studied during 24 h (short-term effect) and 30 days (long-term effect) using high-salt (18% NaCl) and -fructose (10%) diet (HSFD)-induced hypertension. Data showed that, 4 h post-administration of VPH and VPH-I (200 mg/kg BW), the systolic blood pressure of rats was reduced by about 6 and 9 mmHg, respectively. These effects were similar to that obtained with Captopril (~9 mmHg at t = 4 h). On the other hand, exposing the rats to daily to HSFD, coupled to the administration of viscera peptides, was found to attenuate hypertension. In addition, the proteins' treatments were able to correct lipid and glycemic disorders, by reducing the total cholesterol and triglyceride contents and resorting to the plasma glucose level, compared to the HSFD group. Overall, the present findings demonstrated the preventive effect of VPH-peptides from hypertension complications, as a result of their biological properties.
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Affiliation(s)
- Ola Abdelhedi
- Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax (ENIS), University of Sfax, P.O. Box 1173, Sfax 3038, Tunisia.
| | - Hana Khemakhem
- Laboratory of Biochemistry, CHU HediChaker, University of Sfax, Sfax 3000, Tunisia.
| | - Rim Nasri
- Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax (ENIS), University of Sfax, P.O. Box 1173, Sfax 3038, Tunisia.
- Higher Institute of Biotechnology of Monastir, University of Monastir, Monastir 5000, Tunisia.
| | - Mourad Jridi
- Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax (ENIS), University of Sfax, P.O. Box 1173, Sfax 3038, Tunisia.
- Higher Institute of Biotechnology of Beja, University of Jendouba, Beja 9000, Tunisia.
| | - Leticia Mora
- Instituto de Agroquímica y Tecnologíade Alimentos (CSIC), Avenue Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Ikram Ben Amor
- Centre Régional de Transfusion Sanguine de Sfax, Route El-Ain Km 0.5, Sfax 3003, Tunisia.
| | - Kamel Jamoussi
- Laboratory of Biochemistry, CHU HediChaker, University of Sfax, Sfax 3000, Tunisia.
| | - Fidel Toldrá
- Instituto de Agroquímica y Tecnologíade Alimentos (CSIC), Avenue Agustín Escardino 7, Paterna, 46980 Valencia, Spain.
| | - Jalel Gargouri
- Centre Régional de Transfusion Sanguine de Sfax, Route El-Ain Km 0.5, Sfax 3003, Tunisia.
| | - Moncef Nasri
- Laboratory of Enzyme Engineering and Microbiology, National School of Engineering of Sfax (ENIS), University of Sfax, P.O. Box 1173, Sfax 3038, Tunisia.
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73
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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: 13] [Impact Index Per Article: 2.6] [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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74
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Heart failure with preserved ejection fraction: A systemic disease linked to multiple comorbidities, targeting new therapeutic options. Arch Cardiovasc Dis 2018; 111:766-781. [DOI: 10.1016/j.acvd.2018.04.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2018] [Revised: 04/03/2018] [Accepted: 04/05/2018] [Indexed: 12/13/2022]
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75
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Kurtz TW, DiCarlo SE, Pravenec M, Morris RC. Changing views on the common physiologic abnormality that mediates salt sensitivity and initiation of salt-induced hypertension: Japanese research underpinning the vasodysfunction theory of salt sensitivity. Hypertens Res 2018; 42:6-18. [DOI: 10.1038/s41440-018-0122-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2018] [Revised: 07/26/2018] [Accepted: 07/27/2018] [Indexed: 12/24/2022]
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76
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Bie P. Mechanisms of sodium balance: total body sodium, surrogate variables, and renal sodium excretion. Am J Physiol Regul Integr Comp Physiol 2018; 315:R945-R962. [DOI: 10.1152/ajpregu.00363.2017] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The classical concepts of human sodium balance include 1) a total pool of Na+ of ≈4,200 mmol (total body sodium, TBS) distributed primarily in the extracellular fluid (ECV) and bone, 2) intake variations of 0.03 to ≈6 mmol·kg body mass−1·day−1, 3) asymptotic transitions between steady states with a halftime (T½) of 21 h, 4) changes in TBS driven by sodium intake measuring ≈1.3 day [ΔTBS/Δ(Na+ intake/day)], 5) adjustment of Na+ excretion to match any diet thus providing metabolic steady state, and 6) regulation of TBS via controlled excretion (90–95% renal) mediated by surrogate variables. The present focus areas include 1) uneven, nonosmotic distribution of increments in TBS primarily in “skin,” 2) long-term instability of TBS during constant Na+ intake, and 3) physiological regulation of renal Na+ excretion primarily by neurohumoral mechanisms dependent on ECV rather than arterial pressure. Under physiological conditions 1) the nonosmotic distribution of Na+ seems conceptually important, but quantitatively ill defined; 2) long-term variations in TBS represent significant deviations from steady state, but the importance is undetermined; and 3) the neurohumoral mechanisms of sodium homeostasis competing with pressure natriuresis are essential for systematic analysis of short-term and long-term regulation of TBS. Sodium homeostasis and blood pressure regulation are intimately related. Real progress is slow and will accelerate only through recognition of the present level of ignorance. Nonosmotic distribution of sodium, pressure natriuresis, and volume-mediated regulation of renal sodium excretion are essential intertwined concepts in need of clear definitions, conscious models, and future attention.
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Affiliation(s)
- Peter Bie
- Department of Cardiovascular and Renal Research, Institute of Molecular Medicine, University of Southern Denmark, Odense, Denmark
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77
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Siriopol D, Covic A, Iliescu R, Kanbay M, Tautu O, Radulescu L, Mitu O, Salaru D, Dorobantu M. Arterial stiffness mediates the effect of salt intake on systolic blood pressure. J Clin Hypertens (Greenwich) 2018; 20:1587-1594. [DOI: 10.1111/jch.13399] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Accepted: 08/29/2018] [Indexed: 01/01/2023]
Affiliation(s)
- Dimitrie Siriopol
- Nephrology Department; “Grigore T. Popa” University of Medicine and Pharmacy; Iasi Romania
| | - Adrian Covic
- Nephrology Department; “Grigore T. Popa” University of Medicine and Pharmacy; Iasi Romania
| | - Radu Iliescu
- Pharmacology Department; “Grigore T. Popa” University of Medicine and Pharmacy; Iasi Romania
| | - Mehmet Kanbay
- Division of Nephrology, Department of Medicine; Koc University School of Medicine; Istanbul Turkey
| | - Oana Tautu
- Cardiology Department; “Carol Davila” University of Medicine and Pharmacy; Bucharest Romania
| | - Luminita Radulescu
- Nephrology Department; “Carol Davila” University of Medicine and Pharmacy; Bucharest Romania
| | - Ovidiu Mitu
- Cardiology Department; “Grigore T. Popa” University of Medicine and Pharmacy; Iasi Romania
| | - Delia Salaru
- Cardiology Department; “Grigore T. Popa” University of Medicine and Pharmacy; Iasi Romania
| | - Maria Dorobantu
- Cardiology Department; “Carol Davila” University of Medicine and Pharmacy; Bucharest Romania
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78
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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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79
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80
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Tudorancea I, Lohmeier TE, Alexander BT, Pieptu D, Serban DN, Iliescu R. Reduced Renal Mass, Salt-Sensitive Hypertension Is Resistant to Renal Denervation. Front Physiol 2018; 9:455. [PMID: 29760664 PMCID: PMC5936777 DOI: 10.3389/fphys.2018.00455] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 04/13/2018] [Indexed: 11/18/2022] Open
Abstract
Aim: Activation of the sympathetic nervous system is common in resistant hypertension (RHT) and also in chronic kidney disease (CKD), a prevalent condition among resistant hypertensives. However, renal nerve ablation lowers blood pressure (BP) only in some patients with RHT. The influence of loss of nephrons per se on the antihypertensive response to renal denervation (RDNx) is unclear and was the focus of this study. Methods: Systemic hemodynamics and sympathetically mediated low frequency oscillations of systolic BP were determined continuously from telemetrically acquired BP recordings in rats before and after surgical excision of ∼80% of renal mass and subsequent RDNx. Results: After reduction of renal mass, rats fed a high salt (HS) diet showed sustained increases in mean arterial pressure (108 ± 3 mmHg to 128 ± 2 mmHg) and suppression of estimated sympathetic activity (∼15%), responses that did not occur with HS before renal ablation. After denervation of the remnant kidney, arterial pressure fell (to 104 ± 4 mmHg), estimated sympathetic activity and heart rate (HR) increased concomitantly, but these changes gradually returned to pre-denervation levels over 2 weeks of follow up. Subsequently, sympathoinhibition with clonidine did not alter arterial pressure while significantly suppressing estimated sympathetic activity and HR. Conclusion: These results indicate that RDNx does not chronically lower arterial pressure in this model of salt-sensitive hypertension associated with substantial nephron loss, but without ischemia and increased sympathetic activity, thus providing further insight into conditions likely to impact the antihypertensive response to renal-specific sympathoinhibition in subjects with CKD.
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Affiliation(s)
- Ionut Tudorancea
- Cardiology Division Department of Internal Medicine, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania.,Department of Physiology, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania.,CHRONEX-RD Biomedical Research Center, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania
| | - Thomas E Lohmeier
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States
| | - Barbara T Alexander
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States
| | - Dragos Pieptu
- Department of Plastic and Reconstructive Surgery, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania
| | - Dragomir N Serban
- Department of Physiology, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania
| | - Radu Iliescu
- CHRONEX-RD Biomedical Research Center, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania.,Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, MS, United States.,Department of Pharmacology, Grigore T. Popa University of Medicine and Pharmacy, Iași, Romania.,Regional Institute of Oncology, TRANSCEND Research Center, Iași, Romania
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81
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The American Heart Association Scientific Statement on salt sensitivity of blood pressure: Prompting consideration of alternative conceptual frameworks for the pathogenesis of salt sensitivity? J Hypertens 2018. [PMID: 28650918 DOI: 10.1097/hjh.0000000000001458] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
: Recently, the American Heart Association (AHA) published a scientific statement on salt sensitivity of blood pressure which emphasized a decades old conceptual framework for the pathogenesis of this common disorder. Here we examine the extent to which the conceptual framework for salt sensitivity emphasized in the AHA Statement accommodates contemporary findings and views of the broader scientific community on the pathogenesis of salt sensitivity. In addition, we highlight alternative conceptual frameworks and important contemporary theories of salt sensitivity that are little discussed in the AHA Statement. We suggest that greater consideration of conceptual frameworks and theories for salt sensitivity beyond those emphasized in the AHA Statement may help to advance understanding of the pathogenesis of salt-induced increases in blood pressure and, in consequence, may lead to improved approaches to preventing and treating this common disorder.
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82
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Titze J, Luft FC. Speculations on salt and the genesis of arterial hypertension. Kidney Int 2018; 91:1324-1335. [PMID: 28501304 DOI: 10.1016/j.kint.2017.02.034] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 02/17/2017] [Accepted: 02/21/2017] [Indexed: 12/25/2022]
Abstract
Blood pressure salt sensitivity and salt resistance are mechanistically imperfectly explained. A prescient systems medicine approach by Guyton and colleagues-more than 50 years ago-suggested how salt intake might influence blood pressure. They proposed that a high-salt diet engenders sodium accumulation, volume expansion, cardiac output adjustments, and then autoregulation for flow maintenance. The autoregulation in all vascular beds increases systemic vascular resistance, causing the kidneys to excrete more salt and water, thus reducing systems to normal and minimizing any changes in blood pressure. This schema, which is remarkably all encompassing, included all regulatory mechanisms Guyton could identify at the time. Guyton introduced the idea that the kidney is central, particularly concerning the regulation of renal pressure natriuresis. Numerous criticisms have been subsequently raised, particularly recently. Kurtz and colleagues argue that the ability of individuals to respond with an appropriate vasodilatory response to increased salt intake is pivotal. Data exist to address that issue. Salt-resistant hypertensive models provide additional information. We identified a mendelian form of hypertension not related to sodium reabsorption in the distal nephron. The hypertension develops because of increased systemic vascular resistance. In addition, we rediscovered a third salt-storage glycose-aminoglycan-related compartment, largely in the skin. This compartment operates independently of renal function, and when perturbed, is associated with salt sensitivity. More recently, we found novel molecular mechanisms demonstrating how large salt quantities are excreted by the kidneys with minimal water losses. We introduce novel interpretations as to how the kidneys excrete salt when the intake is high. The findings could have relevance as to how blood pressure may be regulated at varying salt intakes. Our purposes are to provide the readership with a banquet of thoughts to digest, to pursue Guyton's ideas, and to adjust them accordingly.
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Affiliation(s)
- Jens Titze
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Friedrich C Luft
- Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA; Experimental and Clinical Research Center, Max-Delbrück Center for Molecular Medicine, Charité Medical Faculty, Berlin, Germany.
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83
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The pivotal role of renal vasodysfunction in salt sensitivity and the initiation of salt-induced hypertension. Curr Opin Nephrol Hypertens 2018; 27:83-92. [DOI: 10.1097/mnh.0000000000000394] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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84
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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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85
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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: 256] [Impact Index Per Article: 42.7] [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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86
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Elijovich F, Milne GL, Brown NJ, Laniado-Schwartzman M, Laffer CL. Two Pools of Epoxyeicosatrienoic Acids in Humans: Alterations in Salt-Sensitive Normotensive Subjects. Hypertension 2017; 71:346-355. [PMID: 29279315 DOI: 10.1161/hypertensionaha.117.10392] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 10/14/2017] [Accepted: 11/28/2017] [Indexed: 11/16/2022]
Abstract
We measured epoxyeicosatrienoic acids (EETs) and dihydroxyeicosatrienoic acids (DHETs) in 21 normotensive subjects classified as salt resistant (13) or salt sensitive (8) with an inpatient protocol of salt loading (460 mEq Na+/24 hours, HiNa) and depletion (10 mEq Na+/24 hours+furosemide 40 mg×3, LoNa). No urine EETs were detected; hence, enzyme linked innumosorbent assay 14,15-DHETs (dihydroxyeicosatrienoic acids) were considered the total converted 14,15-urine pool. We report ultra-performance liquid chromatography/tandem mass spectrometry plasma EETs, DHETs, and their sum (plasma total pool) for the 3 regioisomers (8,9-, 11,12-, 14,15-) and their sum (08,15-). In salt-resistant subjects, urine total pool was unchanged by HiNa, decreased by LoNa, and correlated with urine sodium excretion, fractional excretion of Na+, and Na+/K+ ratio for the 3 days of the experiment combined (P<0.03). In contrast, plasma total pool increased in LoNa and did not correlate with natriuresis or Na+/K+ ratio but showed correlations between EETs, blood pressures, and catecholamines and between DHETs and aldosterone (P<0.03). Urine total pool of salt-sensitive was lower than that of salt-resistant subjects in certain phases of the experiment, lacked responses to changes in salt balance, and exhibited limited correlations with natriuresis and Na+/K+ ratio during LoNa only. Plasma total pool of salt-sensitive was lower than in salt-resistant subjects and did not correlate with blood pressures or aldosterone but did with catecholamines. We conclude that the urine total pool reflects a renal pool involved in regulation of natriuresis, whereas the plasma total pools are of systemic origin, uninvolved in Na+ excretion, perhaps contributing to regulation of vascular tone. Data suggest that abnormalities in EETs in salt-sensitive subjects participate in their renal or vascular dysfunction, which has potential therapeutic implications.
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Affiliation(s)
- Fernando Elijovich
- From the Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (F.E., G.L.M., N.J.B., C.L.L.); and Department of Pharmacology, New York Medical College, Valhalla (M.L.-S.).
| | - Ginger L Milne
- From the Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (F.E., G.L.M., N.J.B., C.L.L.); and Department of Pharmacology, New York Medical College, Valhalla (M.L.-S.)
| | - Nancy J Brown
- From the Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (F.E., G.L.M., N.J.B., C.L.L.); and Department of Pharmacology, New York Medical College, Valhalla (M.L.-S.)
| | - Michal Laniado-Schwartzman
- From the Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (F.E., G.L.M., N.J.B., C.L.L.); and Department of Pharmacology, New York Medical College, Valhalla (M.L.-S.)
| | - Cheryl L Laffer
- From the Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (F.E., G.L.M., N.J.B., C.L.L.); and Department of Pharmacology, New York Medical College, Valhalla (M.L.-S.)
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87
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Aronow WS. Reduction in dietary sodium improves blood pressure and reduces cardiovascular events and mortality. ANNALS OF TRANSLATIONAL MEDICINE 2017; 5:405. [PMID: 29152505 DOI: 10.21037/atm.2017.08.06] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Wilbert S Aronow
- Cardiology Division, Department of Medicine, Westchester Medical Center and New York Medical College, Valhalla, NY, USA
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88
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Blaustein MP. The pump, the exchanger, and the holy spirit: origins and 40-year evolution of ideas about the ouabain-Na + pump endocrine system. Am J Physiol Cell Physiol 2017; 314:C3-C26. [PMID: 28971835 DOI: 10.1152/ajpcell.00196.2017] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Two prescient 1953 publications set the stage for the elucidation of a novel endocrine system: Schatzmann's report that cardiotonic steroids (CTSs) are all Na+ pump inhibitors, and Szent-Gyorgi's suggestion that there is an endogenous "missing screw" in heart failure that CTSs like digoxin may replace. In 1977 I postulated that an endogenous Na+ pump inhibitor acts as a natriuretic hormone and simultaneously elevates blood pressure (BP) in salt-dependent hypertension. This hypothesis was based on the idea that excess renal salt retention promoted the secretion of a CTS-like hormone that inhibits renal Na+ pumps and salt reabsorption. The hormone also inhibits arterial Na+ pumps, elevates myocyte Na+ and promotes Na/Ca exchanger-mediated Ca2+ gain. This enhances vasoconstriction and arterial tone-the hallmark of hypertension. Here I describe how those ideas led to the discovery that the CTS-like hormone is endogenous ouabain (EO), a key factor in the pathogenesis of hypertension and heart failure. Seminal observations that underlie the still-emerging picture of the EO-Na+ pump endocrine system in the physiology and pathophysiology of multiple organ systems are summarized. Milestones include: 1) cloning the Na+ pump isoforms and physiological studies of mutated pumps in mice; 2) discovery that Na+ pumps are also EO-triggered signaling molecules; 3) demonstration that ouabain, but not digoxin, is hypertensinogenic; 4) elucidation of EO's roles in kidney development and cardiovascular and renal physiology and pathophysiology; 5) discovery of "brain ouabain", a component of a novel hypothalamic neuromodulatory pathway; and 6) finding that EO and its brain receptors modulate behavior and learning.
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Affiliation(s)
- Mordecai P Blaustein
- Departments of Physiology and Medicine, University of Maryland School of Medicine , Baltimore, Maryland
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89
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Palygin O, Levchenko V, Ilatovskaya DV, Pavlov TS, Pochynyuk OM, Jacob HJ, Geurts AM, Hodges MR, Staruschenko A. Essential role of Kir5.1 channels in renal salt handling and blood pressure control. JCI Insight 2017; 2:92331. [PMID: 28931751 PMCID: PMC5621918 DOI: 10.1172/jci.insight.92331] [Citation(s) in RCA: 68] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Accepted: 08/08/2017] [Indexed: 01/07/2023] Open
Abstract
Supplementing diets with high potassium helps reduce hypertension in humans. Inwardly rectifying K+ channels Kir4.1 (Kcnj10) and Kir5.1 (Kcnj16) are highly expressed in the basolateral membrane of distal renal tubules and contribute to Na+ reabsorption and K+ secretion through the direct control of transepithelial voltage. To define the importance of Kir5.1 in blood pressure control under conditions of salt-induced hypertension, we generated a Kcnj16 knockout in Dahl salt-sensitive (SS) rats (SSKcnj16-/-). SSKcnj16-/- rats exhibited hypokalemia and reduced blood pressure, and when fed a high-salt diet (4% NaCl), experienced 100% mortality within a few days triggered by salt wasting and severe hypokalemia. Electrophysiological recordings of basolateral K+ channels in the collecting ducts isolated from SSKcnj16-/- rats revealed activity of only homomeric Kir4.1 channels. Kir4.1 expression was upregulated in SSKcnj16-/- rats, but the protein was predominantly localized in the cytosol in SSKcnj16-/- rats. Benzamil, but not hydrochlorothiazide or furosemide, rescued this phenotype from mortality on a high-salt diet. Supplementation of high-salt diet with increased potassium (2% KCl) prevented mortality in SSKcnj16-/- rats and prevented or mitigated hypertension in SSKcnj16-/- or control SS rats, respectively. Our results demonstrate that Kir5.1 channels are key regulators of renal salt handling in SS hypertension.
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Affiliation(s)
- Oleg Palygin
- Department of Physiology and
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | | | | | | | - Oleh M. Pochynyuk
- Department of Integrative Biology, University of Texas Health Science Center Medical School, Houston, Texas, USA
| | - Howard J. Jacob
- Department of Physiology and
- Human and Molecular Genetics Center and
| | - Aron M. Geurts
- Department of Physiology and
- Human and Molecular Genetics Center and
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Matthew R. Hodges
- Department of Physiology and
- Neuroscience Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
| | - Alexander Staruschenko
- Department of Physiology and
- Cardiovascular Center, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
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90
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de Beus E, de Jager RL, Beeftink MM, Sanders MF, Spiering W, Vonken EJ, Voskuil M, Bots ML, Blankestijn PJ. Salt intake and blood pressure response to percutaneous renal denervation in resistant hypertension. J Clin Hypertens (Greenwich) 2017; 19:1125-1133. [PMID: 28929577 DOI: 10.1111/jch.13085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Revised: 05/07/2017] [Accepted: 05/21/2017] [Indexed: 01/26/2023]
Abstract
The effect of lowering sympathetic nerve activity by renal denervation (RDN) is highly variable. With the exception of office systolic blood pressure (BP), predictors of the BP-lowering effect have not been identified. Because dietary sodium intake influences sympathetic drive, and, conversely, sympathetic activity influences salt sensitivity in hypertension, we investigated 24-hour urinary sodium excretion in participants of the SYMPATHY trial. SYMPATHY investigated RDN in patients with resistant hypertension. Both 24-hour ambulatory and office BP measurements were end points. No relationship was found for baseline sodium excretion and change in BP 6 months after RDN in multivariable-adjusted regression analysis. Change in the salt intake-measured BP relationships at 6 months vs baseline was used as a measure for salt sensitivity. BP was 8 mm Hg lower with similar salt intake after RDN, suggesting a decrease in salt sensitivity. However, the change was similar in the control group, and thus not attributable to RDN.
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Affiliation(s)
- Esther de Beus
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Rosa L de Jager
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Martine M Beeftink
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Margreet F Sanders
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Wilko Spiering
- Department of Vascular Medicine, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Evert-Jan Vonken
- Department of Radiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michiel Voskuil
- Department of Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Michiel L Bots
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht, The Netherlands
| | - Peter J Blankestijn
- Department of Nephrology and Hypertension, University Medical Center Utrecht, Utrecht, The Netherlands
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91
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Palygin O, Evans LC, Cowley AW, Staruschenko A. Acute In Vivo Analysis of ATP Release in Rat Kidneys in Response to Changes of Renal Perfusion Pressure. J Am Heart Assoc 2017; 6:JAHA.117.006658. [PMID: 28899893 PMCID: PMC5634305 DOI: 10.1161/jaha.117.006658] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Background ATP and derivatives are recognized to be essential agents of paracrine signaling. It was reported that ATP is an important regulator of the pressure‐natriuresis mechanism. Information on the sources of ATP, the mechanisms of its release, and its relationship to blood pressure has been limited by the inability to precisely measure dynamic changes in intrarenal ATP levels in vivo. Methods and Results Newly developed amperometric biosensors were used to assess alterations in cortical ATP concentrations in response to changes in renal perfusion pressure (RPP) in anesthetized Sprague–Dawley rats. RPP was monitored via the carotid artery; ligations around the celiac/superior mesenteric arteries and the distal aorta were used for manipulation of RPP. Biosensors were acutely implanted in the renal cortex for assessment of ATP. Rise of RPP activated diuresis/natriuresis processes, which were associated with elevated ATP. The increases in cortical ATP concentrations were in the physiological range (1–3 μmol/L) and would be capable of activating most of the purinergic receptors. There was a linear correlation with every 1‐mm Hg rise in RPP resulting in a 70‐nmol/L increase in ATP. Furthermore, this elevation of RPP was accompanied by a 2.5‐fold increase in urinary H2O2. Conclusions Changes in RPP directly correlate with renal sodium excretion and the elevation of cortical ATP. Given the known effects of ATP on regulation of glomerular filtration and tubular transport, the data support a role for ATP release in the rapid natriuretic responses to acute increases in RPP.
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Affiliation(s)
- Oleg Palygin
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
| | - Louise C Evans
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI
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92
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Perrin G, Korb-Savoldelli V, Karras A, Danchin N, Durieux P, Sabatier B. Cardiovascular risk associated with high sodium-containing drugs: A systematic review. PLoS One 2017; 12:e0180634. [PMID: 28683120 PMCID: PMC5500347 DOI: 10.1371/journal.pone.0180634] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 06/19/2017] [Indexed: 11/27/2022] Open
Abstract
Background Excess dietary sodium is associated with increased blood pressure (BP). Some drugs are associated with high sodium intake (in particular effervescent tablets), but the cardiovascular risk associated with such high sodium-containing drugs (HSCD) is largely underevaluated. Objectives To summarize the evidence for a potential cardiovascular risk associated with exposure to HSCD, and to highlight possible risk factors associated with this iatrogenic issue; in general and/or specific populations. Methods We conducted a systematic review, by searching electronic databases including MEDLINE, EMBASE, Web of Science, CENTRAL and grey literature between 1960 and 2015. We included studies that reported modification of cardiovascular parameters or incidence/prevalence of cardiovascular outcomes, between a group of subjects exposed to HSCD relative to a non-exposed group. The threshold used to identify HSCD was 391 mg/day. We did not consider studies evaluating exposure to sodium as an active ingredient or those focusing on dialysis solutions or enteral/parenteral nutrition. Study quality was assessed using the EPHPP tool. Results A total of eight studies met our inclusion criteria. Four reported results for short-term exposure to HSCD (≤ 7 days) on BP fluctuations. One study reported an elevation of BP (associated sodium intake: 1,656 mg/day). Four studies evaluated a long-term exposure (≥ 2 years or discontinuation of a chronic treatment). Two studies reported iatrogenic risk. For these studies, drug associated sodium intake was high (> 1,500 mg/day) in patients with comorbidities (in particular, diabetes mellitus and hypertension). Conclusion Despite numerous study limitations, this systematic review suggests three potential synergistic risk factors for cardiovascular complications after exposure to HSCD: a high sodium intake (≥ 1,500 mg/day), a long duration of exposure, and the presence of comorbidities. Further studies are required to characterize this iatrogenic risk. Trial registration PROSPERO CRD42016047086.
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Affiliation(s)
- Germain Perrin
- Department of Pharmacy, Georges Pompidou European Hospital, Paris, France.,INSERM UMR 1138 Team 22: Information Sciences to Support Personalized Medicine, Paris Descartes University, Paris, France
| | - Virginie Korb-Savoldelli
- Department of Pharmacy, Georges Pompidou European Hospital, Paris, France.,Faculty of Pharmacy, Clinical Pharmacy Department, Paris Saclay University, Châtenay-Malabry, France
| | - Alexandre Karras
- Department of Nephrology, Georges Pompidou European Hospital, Paris, France.,Paris Descartes University, Paris, France
| | - Nicolas Danchin
- Paris Descartes University, Paris, France.,Department of Cardiology, Georges Pompidou European Hospital, Paris, France
| | - Pierre Durieux
- INSERM UMR 1138 Team 22: Information Sciences to Support Personalized Medicine, Paris Descartes University, Paris, France.,Department of Biomedical Informatics and Public Health, Georges Pompidou European Hospital, Paris, France
| | - Brigitte Sabatier
- Department of Pharmacy, Georges Pompidou European Hospital, Paris, France.,INSERM UMR 1138 Team 22: Information Sciences to Support Personalized Medicine, Paris Descartes University, Paris, France
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93
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Ueda K, Nishimoto M, Hirohama D, Ayuzawa N, Kawarazaki W, Watanabe A, Shimosawa T, Loffing J, Zhang MZ, Marumo T, Fujita T. Renal Dysfunction Induced by Kidney-Specific Gene Deletion of Hsd11b2 as a Primary Cause of Salt-Dependent Hypertension. Hypertension 2017; 70:111-118. [PMID: 28559392 DOI: 10.1161/hypertensionaha.116.08966] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Revised: 03/31/2017] [Accepted: 04/10/2017] [Indexed: 01/21/2023]
Abstract
Genome-wide analysis of renal sodium-transporting system has identified specific variations of Mendelian hypertensive disorders, including HSD11B2 gene variants in apparent mineralocorticoid excess. However, these genetic variations in extrarenal tissue can be involved in developing hypertension, as demonstrated in former studies using global and brain-specific Hsd11b2 knockout rodents. To re-examine the importance of renal dysfunction on developing hypertension, we generated kidney-specific Hsd11b2 knockout mice. The knockout mice exhibited systemic hypertension, which was abolished by reducing salt intake, suggesting its salt-dependency. In addition, we detected an increase in renal membrane expressions of cleaved epithelial sodium channel-α and T53-phosphorylated Na+-Cl- cotransporter in the knockout mice. Acute intraperitoneal administration of amiloride-induced natriuresis and increased urinary sodium/potassium ratio more in the knockout mice compared with those in the wild-type control mice. Chronic administration of amiloride and high-KCl diet significantly decreased mean blood pressure in the knockout mice, which was accompanied with the correction of hypokalemia and the resultant decrease in Na+-Cl- cotransporter phosphorylation. Accordingly, a Na+-Cl- cotransporter blocker hydrochlorothiazide significantly decreased mean blood pressure in the knockout mice. Chronic administration of mineralocorticoid receptor antagonist spironolactone significantly decreased mean blood pressure of the knockout mice along with downregulation of cleaved epithelial sodium channel-α and phosphorylated Na+-Cl- cotransporter expression in the knockout kidney. Our data suggest that kidney-specific deficiency of 11β-HSD2 leads to salt-dependent hypertension, which is attributed to mineralocorticoid receptor-epithelial sodium channel-Na+-Cl- cotransporter activation in the kidney, and provides evidence that renal dysfunction is essential for developing the phenotype of apparent mineralocorticoid excess.
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Affiliation(s)
- Kohei Ueda
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.).
| | - Mitsuhiro Nishimoto
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Daigoro Hirohama
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Nobuhiro Ayuzawa
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Wakako Kawarazaki
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Atsushi Watanabe
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Tatsuo Shimosawa
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Johannes Loffing
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Ming-Zhi Zhang
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Takeshi Marumo
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.)
| | - Toshiro Fujita
- From the Division of Clinical Epigenetics, Research Center of Advanced Science and Technology, The University of Tokyo, Japan (K.U., M.N., D.H., N.A., W.K., A.W., T.M., T.F.); Department of Clinical Laboratory, International University of Health and Welfare, School of Medicine, Tokyo, Japan (T.S.); CREST, Japan Agency for Medical Research and Development (AMED), Tokyo (T.S., T.M., T.F.); National Center of Competence in Research 'Kidney Control of Homeostasis', Zurich, Switzerland (J.L.); Institute of Anatomy, University of Zurich, Switzerland (J.L.); Division of Nephrology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN (M.-Z.Z.); and Department of Nephrology and Endocrinology, National Defense Medical College, Saitama, Japan (A.W.).
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94
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Pavlov TS, Levchenko V, Ilatovskaya DV, Li H, Palygin O, Pastor-Soler NM, Hallows KR, Staruschenko A. Lack of Effects of Metformin and AICAR Chronic Infusion on the Development of Hypertension in Dahl Salt-Sensitive Rats. Front Physiol 2017; 8:227. [PMID: 28473772 PMCID: PMC5397526 DOI: 10.3389/fphys.2017.00227] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Accepted: 03/31/2017] [Indexed: 12/19/2022] Open
Abstract
In the kidney, reabsorption via the epithelial sodium channel (ENaC) is involved in long-term blood pressure control. Previously we demonstrated that ENaC hyperactivity is associated with development of salt-sensitive (SS) hypertension in Dahl SS rats. AMP-activated kinase (AMPK), playing a role in cellular energy homeostasis, has been shown to decrease ENaC activity. Here, we tested whether metformin and AICAR, two drugs that activate AMPK, affect the development of salt-induced hypertension. High salt diet significantly increased mean arterial pressure (MAP) in Dahl SS rats. Blood pressure elevation was accompanied by a short-term decline of heart rate and increased circadian arterial pressure dipping. Metformin and AICAR were delivered intravenously at doses of 200 and 20 mg/kg/day, respectively. However, both control and drug-treated groups had similar development of high blood pressure within 3 weeks of 8% NaCl dietary salt intake. In the metformin-treated animals MAP reached 164.9 ± 9.1 mmHg, which was not significantly different from the control group (171.8 ± 5.6 mmHg). Patch clamp analysis revealed that the metformin-treated rats had no difference in the activity of ENaC. AICAR treatment also did not affect the development of hypertension and kidney injury. MAP reached 182.8 ± 4.8 and 178.0 ± 2.8 mmHg in AICAR and vehicle treated groups, respectively. Of note, we found that high-salt diet activated AMPK in the Dahl SS rats, and treatment with these AMPK activators had no significant further effect on AMPK activity. We conclude that AMPK activators, at least under these conditions, do not affect development of hypertension during high-salt diet in the Dahl SS rat model.
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Affiliation(s)
- Tengis S Pavlov
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA.,Division of Hypertension and Vascular Research, Henry Ford HospitalDetroit, MI, USA
| | | | | | - Hui Li
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
| | - Oleg Palygin
- Department of Physiology, Medical College of WisconsinMilwaukee, WI, USA
| | - Nuria M Pastor-Soler
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
| | - Kenneth R Hallows
- Division of Nephrology and Hypertension, Department of Medicine, Keck School of Medicine, University of Southern California, Los AngelesLos Angeles, CA, USA
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95
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Kurtz TW, DiCarlo SE, Pravenec M, Morris RC. An Appraisal of Methods Recently Recommended for Testing Salt Sensitivity of Blood Pressure. J Am Heart Assoc 2017; 6:JAHA.117.005653. [PMID: 28365569 PMCID: PMC5533040 DOI: 10.1161/jaha.117.005653] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Theodore W Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, San Francisco, CA
| | | | - Michal Pravenec
- Institute of Physiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic
| | - R Curtis Morris
- Department of Medicine, University of California, San Francisco, San Francisco, CA
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96
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Abstract
Salt resistance/sensitivity refers specifically to the effect of dietary sodium chloride (salt) intake on BP. Increased dietary salt intake promotes an early and uniform expansion of extracellular fluid volume and increased cardiac output. To compensate for these hemodynamic changes and maintain constant BP in salt resistance, renal and peripheral vascular resistance falls and is associated with an increase in production of nitric oxide. In contrast, the decline in peripheral vascular resistance and the increase in nitric oxide are impaired or absent in salt sensitivity, promoting an increase in BP in these individuals. Endothelial dysfunction may pose a particularly significant risk factor in the development of salt sensitivity and subsequent hypertension. Vulnerable salt-sensitive populations may have in common underlying endothelial dysfunction due to genetic or environmental influences. These individuals may be very sensitive to the hemodynamic stress of increased effective blood volume, setting in motion untoward molecular and biochemical events that lead to overproduction of TGF-β, oxidative stress, and limited bioavailable nitric oxide. Finally, chronic high-salt ingestion produces endothelial dysfunction, even in salt-resistant subjects. Thus, the complex syndrome of salt sensitivity may be a function of the endothelium, which is integrally involved in the vascular responses to high salt intake.
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Affiliation(s)
| | - Louis J Dell'Italia
- Departments of Medicine and.,Department of Medicine, Veterans Affairs Medical Center, Birmingham, Alabama
| | - Paul W Sanders
- Departments of Medicine and .,Department of Medicine, Veterans Affairs Medical Center, Birmingham, Alabama.,Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, Alabama; and
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97
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Pavlov TS, Staruschenko A. Involvement of ENaC in the development of salt-sensitive hypertension. Am J Physiol Renal Physiol 2016; 313:F135-F140. [PMID: 28003189 DOI: 10.1152/ajprenal.00427.2016] [Citation(s) in RCA: 59] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 12/20/2016] [Accepted: 12/20/2016] [Indexed: 02/07/2023] Open
Abstract
Salt-sensitive hypertension is associated with renal and vascular dysfunctions, which lead to impaired fluid excretion, increased cardiac output, and total peripheral resistance. It is commonly accepted that increased renal sodium handling and plasma volume expansion are necessary factors for the development of salt-induced hypertension. The epithelial sodium channel (ENaC) is a trimeric ion channel expressed in the distal nephron that plays a critical role in the regulation of sodium reabsorption in both normal and pathological conditions. In this mini-review, we summarize recent studies investigating the role of ENaC in the development of salt-sensitive hypertension. On the basis of experimental data obtained from the Dahl salt-sensitive rats, we and others have demonstrated that abnormal ENaC activation in response to a dietary NaCl load contributes to the development of high blood pressure in this model. The role of different humoral factors, such as the components of the renin-angiotensin-aldosterone system, members of the epidermal growth factors family, arginine vasopressin, and oxidative stress mediating the effects of dietary salt on ENaC are discussed in this review to highlight future research directions and to determine potential molecular targets for drug development.
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Affiliation(s)
- Tengis S Pavlov
- Division of Hypertension and Vascular Research, Henry Ford Hospital, Detroit, Michigan; and
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98
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Clemmer JS, Pruett WA, Coleman TG, Hall JE, Hester RL. Mechanisms of blood pressure salt sensitivity: new insights from mathematical modeling. Am J Physiol Regul Integr Comp Physiol 2016; 312:R451-R466. [PMID: 27974315 DOI: 10.1152/ajpregu.00353.2016] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 12/06/2016] [Accepted: 12/06/2016] [Indexed: 12/24/2022]
Abstract
Mathematical modeling is an important tool for understanding quantitative relationships among components of complex physiological systems and for testing competing hypotheses. We used HumMod, a large physiological model, to test hypotheses of blood pressure (BP) salt sensitivity. Systemic hemodynamics, renal, and neurohormonal responses to chronic changes in salt intake were examined during normal renal function, fixed low or high plasma angiotensin II (ANG II) levels, bilateral renal artery stenosis, increased renal sympathetic nerve activity (RSNA), and decreased nephron numbers. Simulations were run for 4 wk at salt intakes ranging from 30 to 1,000 mmol/day. Reducing functional kidney mass or fixing ANG II increased salt sensitivity. Salt sensitivity, associated with inability of ANG II to respond to changes in salt intake, occurred with smaller changes in renal blood flow but greater changes in glomerular filtration rate, renal sodium reabsorption, and total peripheral resistance (TPR). However, clamping TPR at normal or high levels had no major effect on salt sensitivity. There were no clear relationships between BP salt sensitivity and renal vascular resistance or extracellular fluid volume. Our robust mathematical model of cardiovascular, renal, endocrine, and sympathetic nervous system physiology supports the hypothesis that specific types of kidney dysfunction, associated with impaired regulation of ANG II or increased tubular sodium reabsorption, contribute to BP salt sensitivity. However, increased preglomerular resistance, increased RSNA, or inability to decrease TPR does not appear to influence salt sensitivity. This model provides a platform for testing competing concepts of long-term BP control during changes in salt intake.
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Affiliation(s)
- John S Clemmer
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - W Andrew Pruett
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Thomas G Coleman
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - John E Hall
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi
| | - Robert L Hester
- Department of Physiology and Biophysics, Center for Computational Medicine, University of Mississippi Medical Center, Jackson, Mississippi
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99
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Lohmeier TE, Pruett WA. Illogical Critiques of the Pressure Natriuresis Theory of Chronic Hypertension. Am J Hypertens 2016. [PMID: 28637272 DOI: 10.1093/ajh/hpw076] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Thomas E Lohmeier
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - William Andrew Pruett
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
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100
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Kurtz TW, DiCarlo SE, Morris RC. Logical Issues With the Pressure Natriuresis Theory of Chronic Hypertension. Am J Hypertens 2016. [PMID: 28637271 DOI: 10.1093/ajh/hpw073] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
The term "abnormal pressure natriuresis" refers to a subnormal effect of a given level of blood pressure (BP) on sodium excretion. It is widely believed that abnormal pressure natriuresis causes an initial increase in BP to be sustained. We refer to this view as the "pressure natriuresis theory of chronic hypertension." The proponents of the theory contend that all forms of chronic hypertension are sustained by abnormal pressure natriuresis, irrespective of how hypertension is initiated. This theory would appear to follow from "the three laws of long-term arterial pressure regulation" stated by Guyton and Coleman more than 3 decades ago. These "laws" articulate the concept that for a given level of salt intake, the relationship between arterial pressure and sodium excretion determines the chronic level of BP. Here, we review and examine the recent assertion by Beard that these "laws" of long-term BP control amount to nothing more than a series of tautologies. Our analysis supports Beard's assertion, and also indicates that contemporary investigators often use tautological reasoning in support of the pressure natriuresis theory of chronic hypertension. Although the theory itself is not a tautology, it does not appear to be testable because it holds that abnormal pressure natriuresis causes salt-induced hypertension to be sustained through abnormal increases in cardiac output that are too small to be detected.
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Affiliation(s)
- Theodore W Kurtz
- Department of Laboratory Medicine, University of California, San Francisco, California, USA
| | - Stephen E DiCarlo
- Department of Physiology, Wayne State University, Detroit, Michigan, USA
| | - R Curtis Morris
- Department of Medicine, University of California, San Francisco, California, USA
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