1
|
Wang Y, Wang M, Su H, Song J, Ren M, Hu P, Liu G, Tong X. SERCA2 dysfunction triggers hypertension by interrupting mitochondrial homeostasis and provoking oxidative stress. Free Radic Biol Med 2024; 212:284-294. [PMID: 38163553 DOI: 10.1016/j.freeradbiomed.2023.12.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 12/27/2023] [Accepted: 12/29/2023] [Indexed: 01/03/2024]
Abstract
BACKGROUND AND AIM Sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) is critical in maintaining Ca2+ homeostasis. The cysteine 674 (C674) is the key redox regulatory cysteine in regulating SERCA2 activity, which is irreversibly oxidized in the renal cortex of hypertensive mice. We have reported that the substitution of C674 by serine causes SERCA2 dysfunction and increases blood pressure by induction of endoplasmic reticulum stress (ERS). This study is to explore whether the dysfunction of SERCA2 causes hypertension by interrupting mitochondrial homeostasis and inducing oxidative stress. METHODS & RESULTS We used heterozygous SERCA2 C674S gene mutation knock-in (SKI) mice, where one copy of C674 was substituted by serine to represent partial C674 oxidation. In renal proximal tubule (RPT) cells, the substitution of C674 by serine decreased mitochondrial Ca2+ content, increased mitochondrial membrane potential, ATP content, and reactive oxygen species (ROS), which could be reversed by ERS inhibitor 4-phenylbutyric acid or SERCA2 agonist CDN1163. In SKI RPT cells, the redox modulator Tempol alleviated oxidative stress, downregulated the protein expression of ERS markers and soluble epoxide hydrolase, upregulated the protein expression of dopamine D1 receptor, and reduced Na+/K+- ATPase activity. In SKI mice, SERCA2 agonists CDN1163 and [6]-Gingerol, or the redox modulator Tempol increased urine output and lowered blood pressure. CONCLUSION The irreversible oxidation of C674 is not only an indicator of increased ROS, but also further inducing oxidative stress to cause hypertension. Activation of SERCA2 or inhibition of oxidative stress is beneficial to alleviate hypertension caused by SERCA2 dysfunction.
Collapse
Affiliation(s)
- Yaping Wang
- Innovative Drug Research Centre, Chongqing University, Chongqing, 401331, China
| | - Min Wang
- Innovative Drug Research Centre, Chongqing University, Chongqing, 401331, China
| | - Hang Su
- Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou Province, 563006, China
| | - Jiarou Song
- Innovative Drug Research Centre, Chongqing University, Chongqing, 401331, China
| | - Minghua Ren
- Department of Urinary Surgery, The First Affiliated Hospital of Harbin Medical University, Harbin, Heilongjiang Province, 150001, China
| | - Pingping Hu
- College of Pharmacy, Chongqing Medical University, Chongqing, 400016, China
| | - Gang Liu
- Henan Key Laboratory of Medical Tissue Regeneration, College of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, Henan Province, 453003, China.
| | - Xiaoyong Tong
- Innovative Drug Research Centre, Chongqing University, Chongqing, 401331, China; Jinfeng Laboratory, Chongqing, 401329, China.
| |
Collapse
|
2
|
Suzuki D, Hoshide S, Kario K. Renal Sodium Handling: Perspective on Adaptation to Clinical Practice. Am J Hypertens 2021; 34:332-334. [PMID: 33438727 DOI: 10.1093/ajh/hpab001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2020] [Accepted: 01/12/2021] [Indexed: 11/13/2022] Open
Affiliation(s)
- Daisuke Suzuki
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Tochigi, Japan
- Department of Medicine, Division of Endocrinology and Metabolism, Jichi Medical University Saitama Medical Center, Saitama, Japan
| | - Satoshi Hoshide
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Tochigi, Japan
| | - Kazuomi Kario
- Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University School of Medicine, Tochigi, Japan
| |
Collapse
|
3
|
Liu G, Wu F, Jiang X, Que Y, Qin Z, Hu P, Lee KSS, Yang J, Zeng C, Hammock BD, Tong X. Inactivation of Cys 674 in SERCA2 increases BP by inducing endoplasmic reticulum stress and soluble epoxide hydrolase. Br J Pharmacol 2020; 177:1793-1805. [PMID: 31758704 DOI: 10.1111/bph.14937] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2019] [Revised: 10/29/2019] [Accepted: 10/30/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE The kidney is essential in regulating sodium homeostasis and BP. The irreversible oxidation of Cys674 (C674) in the sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) is increased in the renal cortex of hypertensive mice. Whether inactivation of C674 promotes hypertension is unclear. Here we have investigated the effects on BP of the inactivation of C674, and its role in the kidney. EXPERIMENTAL APPROACH We used heterozygous SERCA2 C674S knock-in (SKI) mice, where half of C674 was substituted by serine, to represent partial irreversible oxidation of C674. The BP, urine volume, and urine composition of SKI mice and their littermate wild-type (WT) mice were measured. The kidneys were collected for cell culture, Na+ /K+ -ATPase activity, protein expression, and immunohistological analysis. KEY RESULTS Compared with WT mice, SKI mice had higher BP, lower urine volume and sodium excretion, up-regulated endoplasmic reticulum (ER) stress markers and soluble epoxide hydrolase (sEH), and down-regulated dopamine D1 receptors in renal cortex and cells from renal proximal tubule. ER stress and sEH were mutually regulated, and both upstream of D1 receptors. Inhibition of ER stress or sEH up-regulated expression of D1 receptors, decreased the activity of Na+ /K+ -ATPase, increased sodium excretion, and lowered BP in SKI mice. CONCLUSIONS AND IMPLICATIONS The inactivation of SERCA2 C674 promotes the development of hypertension by inducing ER stress and sEH. Our study highlights the importance of C674 redox status in BP control and the contribution of SERCA2 to sodium homeostasis and BP in the kidney.
Collapse
Affiliation(s)
- Gang Liu
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Fuhua Wu
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Xiaoli Jiang
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Yumei Que
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Zhexue Qin
- Department of Cardiovascular Diseases, Xinqiao Hospital, Third Military Medical University, Chongqing, China
| | - Pingping Hu
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Kin Sing Stephen Lee
- Department of Entomology & UCD Comprehensive Cancer Center, University of California-Davis, Davis, California.,Department of Pharmacology & Toxicology, Michigan State University, East Lansing, Michigan
| | - Jian Yang
- Department of Clinical Nutrition, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, Third Military Medical University, Chongqing, China
| | - Bruce D Hammock
- Department of Entomology & UCD Comprehensive Cancer Center, University of California-Davis, Davis, California
| | - Xiaoyong Tong
- School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| |
Collapse
|
4
|
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.
Collapse
|
5
|
Liu ZZ, Bullen A, Li Y, Singh P. Renal Oxygenation in the Pathophysiology of Chronic Kidney Disease. Front Physiol 2017; 8:385. [PMID: 28701959 PMCID: PMC5487476 DOI: 10.3389/fphys.2017.00385] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 05/23/2017] [Indexed: 12/19/2022] Open
Abstract
Chronic kidney disease (CKD) is a significant health problem associated with high morbidity and mortality. Despite significant research into various pathways involved in the pathophysiology of CKD, the therapeutic options are limited in diabetes and hypertension induced CKD to blood pressure control, hyperglycemia management (in diabetic nephropathy) and reduction of proteinuria, mainly with renin-angiotensin blockade therapy. Recently, renal oxygenation in pathophysiology of CKD progression has received a lot of interest. Several advances have been made in our understanding of the determinants and regulators of renal oxygenation in normal and diseased kidneys. The goal of this review is to discuss the alterations in renal oxygenation (delivery, consumption and tissue oxygen tension) in pre-clinical and clinical studies in diabetic and hypertensive CKD along with the underlying mechanisms and potential therapeutic options.
Collapse
Affiliation(s)
- Zhi Zhao Liu
- Division of Nephrology-Hypertension, University of California San Diego School of Medicine, VA San Diego Healthcare SystemSan Diego, CA, United States
| | - Alexander Bullen
- Division of Nephrology-Hypertension, University of California San Diego School of Medicine, VA San Diego Healthcare SystemSan Diego, CA, United States
| | - Ying Li
- Division of Nephrology-Hypertension, University of California San Diego School of Medicine, VA San Diego Healthcare SystemSan Diego, CA, United States
| | - Prabhleen Singh
- Division of Nephrology-Hypertension, University of California San Diego School of Medicine, VA San Diego Healthcare SystemSan Diego, CA, United States
| |
Collapse
|
6
|
Affiliation(s)
- Jian Yang
- Department of Nutrition, Daping Hospital, The Third Military Medical University, Chongqing, China.,Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Pedro A Jose
- Division of Renal Disease & Hypertension, The George Washington University School of Medicine and Health Sciences, Washington, DC
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| |
Collapse
|
7
|
Liu J, Yan Y, Nie Y, Shapiro JI. Na/K-ATPase Signaling and Salt Sensitivity: The Role of Oxidative Stress. Antioxidants (Basel) 2017; 6:E18. [PMID: 28257114 PMCID: PMC5384181 DOI: 10.3390/antiox6010018] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 02/10/2017] [Accepted: 02/22/2017] [Indexed: 02/07/2023] Open
Abstract
Other than genetic regulation of salt sensitivity of blood pressure, many factors have been shown to regulate renal sodium handling which contributes to long-term blood pressure regulation and have been extensively reviewed. Here we present our progress on the Na/K-ATPase signaling mediated sodium reabsorption in renal proximal tubules, from cardiotonic steroids-mediated to reactive oxygen species (ROS)-mediated Na/K-ATPase signaling that contributes to experimental salt sensitivity.
Collapse
Affiliation(s)
- Jiang Liu
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Yanling Yan
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Ying Nie
- Department of Biomedical Sciences, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25755, USA.
| | - Joseph I Shapiro
- Department of Medicine, Joan C. Edwards School of Medicine, Marshall University, Huntington, WV 25701, USA
| |
Collapse
|
8
|
Pruijm M, Hofmann L, Piskunowicz M, Muller ME, Zweiacker C, Bassi I, Vogt B, Stuber M, Burnier M. Determinants of renal tissue oxygenation as measured with BOLD-MRI in chronic kidney disease and hypertension in humans. PLoS One 2014; 9:e95895. [PMID: 24760031 PMCID: PMC3997480 DOI: 10.1371/journal.pone.0095895] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 04/01/2014] [Indexed: 11/19/2022] Open
Abstract
Experimentally renal tissue hypoxia appears to play an important role in the pathogenesis of chronic kidney disease (CKD) and arterial hypertension (AHT). In this study we measured renal tissue oxygenation and its determinants in humans using blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI) under standardized hydration conditions. Four coronal slices were selected, and a multi gradient echo sequence was used to acquire T2* weighted images. The mean cortical and medullary R2* values ( = 1/T2*) were calculated before and after administration of IV furosemide, a low R2* indicating a high tissue oxygenation. We studied 195 subjects (95 CKD, 58 treated AHT, and 42 healthy controls). Mean cortical R2 and medullary R2* were not significantly different between the groups at baseline. In stimulated conditions (furosemide injection), the decrease in R2* was significantly blunted in patients with CKD and AHT. In multivariate linear regression analyses, neither cortical nor medullary R2* were associated with eGFR or blood pressure, but cortical R2* correlated positively with male gender, blood glucose and uric acid levels. In conclusion, our data show that kidney oxygenation is tightly regulated in CKD and hypertensive patients at rest. However, the metabolic response to acute changes in sodium transport is altered in CKD and in AHT, despite preserved renal function in the latter group. This suggests the presence of early renal metabolic alterations in hypertension. The correlations between cortical R2* values, male gender, glycemia and uric acid levels suggest that these factors interfere with the regulation of renal tissue oxygenation.
Collapse
Affiliation(s)
- Menno Pruijm
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Lucie Hofmann
- Department of Nephrology and Hypertension, Bern University Hospital, Bern, Switzerland
| | | | - Marie-Eve Muller
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Carole Zweiacker
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Isabelle Bassi
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| | - Bruno Vogt
- Department of Nephrology and Hypertension, Bern University Hospital, Bern, Switzerland
| | - Matthias Stuber
- Department of Radiology, University Hospital, Lausanne, Switzerland
| | - Michel Burnier
- Department of Nephrology, University Hospital, Lausanne, Switzerland
| |
Collapse
|
9
|
Pechère-Bertschi A, Maillard M, Bischof P, Fathi M, Burnier M. Hemodynamic effect of angiotensin II receptor blockade in postmenopausal women on a high-sodium diet: A double-blind, randomized, placebo-controlled study. Curr Ther Res Clin Exp 2014; 69:467-79. [PMID: 24692821 DOI: 10.1016/j.curtheres.2008.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/26/2008] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Hypertension becomes increasingly prevalent after menopause. Postmenopausal women are more responsive to salt than premenopausal women, and they have been reported to develop marked renal vasoconstriction on a high-sodium diet. OBJECTIVE The aim of this study was to assess whether angiotensin II receptor blockade can restore a normal pattern of renal response to salt in postmenopausal women on a high-sodium diet. We also assessed segmental renal sodium handling in that population. METHODS Normotensive and hypertensive postmenopausal women not receiving hormone replacement therapy were enrolled in this prospective, double-blind, placebo-controlled, crossover study. They were assigned to receive irbesartan 150 mg or placebo for 6 weeks; the sequence in which they received irbesartan or placebo was randomized. During the last week of treatment, they received a high-sodium diet (250 mmol/d). Ambulatory blood pressure (ABP), glomerular filtration rate (GFR), and effective renal plasma flow (ERPF) were measured using sinistrin and para-amino-hippurate clearances. Renal sodium handling was assessed by measuring endogenous lithium clearance on day 7 of the high-salt diet. RESULTS Nineteen women (mean age, 54.7 years; range, 43-72 years; 7 normotensive subjects [mean age, 53.4 years; range, 47-61 years] and 12 hypertensive subjects [mean age, 55.4 years; range, 43-72 years]) were included in the study. When the data for all 19 subjects were pooled, ABP was significantly lower with irbesartan than placebo both during the day (120 [3]/79 [2] vs 127 [3]/85 [2] mm Hg; both, P < 0.01) and at night (systolic BP, 107 [4] vs 111 [4] mm Hg [P < 0.01] and diastolic BP, 71 [2] vs 75 [2] mm Hg [P < 0.05]). Compared with placebo, irbesartan was not associated with a significant change in GFR in either the normotensive or the hypertensive women. When the data for all 19 subjects were pooled, irbesartan was associated with a significant increase in ERPF compared with placebo (372 [21] vs324 [18] mL/min · 1.73 m(2); P < 0.05). When the hypertensive and normotensive women were considered separately, the effect was more pronounced in the hypertensive women than in the normotensive women, but the changes did not reach statistical significance. When the data for all subjects were pooled, irbesartan was associated with a significant increase in daytime urinary sodium excretion compared with placebo (135 [13] vs 106 [13] μmol/min; P < 0.05) and a significant decrease at night (109 [13] vs 136 [19] μmol/min; P < 0.05). Fractional excretion of lithium (FELi), an inverse marker of proximal sodium reabsorption, increased significantly during the daytime with irbesartan compared with placebo (47% [6.5%] vs 35% [4.7%]; P < 0.05). At nighttime, FELi was significantly higher in the hypertensive subjects receiving irbesartan compared with placebo (43% [7.2%] vs 29% [6.5%]; P < 0.05). The fractional distal reabsorption of sodium did not change significantly with irbesartan compared with placebo. CONCLUSIONS The results from this study suggest that angiotensin II receptor blockade had a favorable impact on BP, renal hemodynamics, and renal sodium handling in these salt-replete postmenopausal women. Blockade of the renin-angiotensin system restored the normal pattern of renal response to high sodium intake in these women.
Collapse
Affiliation(s)
- Antoinette Pechère-Bertschi
- Primary Care and Endocrinology, Diabetology and Nutrition Services, University Hospital, Geneva, Switzerland
| | - Marc Maillard
- Nepbrology Service, University Hospital, Lausanne, Switzerland
| | - Paul Bischof
- Reproduction Laboratory, University Hospital, Geneva, Switzerland
| | - Marc Fathi
- Chemical Laboratory, University Hospital, Geneva, Switzerland
| | - Michel Burnier
- Nepbrology Service, University Hospital, Lausanne, Switzerland
| |
Collapse
|
10
|
Zou J, Li Y, Yan CH, Wei FF, Zhang L, Wang JG. Blood pressure in relation to interactions between sodium dietary intake and renal handling. Hypertension 2013; 62:719-25. [PMID: 23959555 DOI: 10.1161/hypertensionaha.111.00776] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
There is abundant evidence that sodium intake is related to blood pressure. However, the relationship varies between individuals and is probably determined by renal sodium handling. We investigated clinic and ambulatory blood pressure in relation to interactions between sodium dietary intake and renal handling, as assessed by 24-hour urinary sodium excretion and endogenous lithium clearance, respectively. We calculated fractional excretion of lithium and fractional distal reabsorption rate of sodium, as markers of proximal and distal sodium handling, respectively. The 766 subjects included 379 men and 478 ambulatory hypertensive patients. They were never treated (n=697) or did not take antihypertensive medication for ≥2 weeks (n=69). In adjusted analyses, none of the associations of urinary sodium excretion, fractional excretion of lithium, and fractional distal reabsorption rate of sodium with clinic or ambulatory blood pressure were statistically significant (P≥0.09). However, there was significant (P=0.01) interaction between urinary sodium excretion and fractional excretion of lithium in relation to nighttime diastolic blood pressure. In tertile 3 but not tertiles 1 and 2 of fractional excretion of lithium, nighttime diastolic pressure was positively associated with urinary sodium excretion (P=0.03). However, nighttime diastolic pressure was higher in tertile 1 than tertile 3 of fractional excretion of lithium (+2.0 mm Hg; P=0.01), especially in the bottom tertile of urinary sodium excretion (+4.9 mm Hg; P<0.001). Similar trends were observed for nighttime systolic pressure and clinic and 24-hour diastolic pressure. In conclusion, sodium dietary intake and proximal tubular handling interact to be associated with blood pressure.
Collapse
Affiliation(s)
- Jun Zou
- The Shanghai Institute of Hypertension, Ruijin 2nd Rd 197, Shanghai 200025, China.
| | | | | | | | | | | |
Collapse
|
11
|
Renal tissue oxygenation in essential hypertension and chronic kidney disease. Int J Hypertens 2013; 2013:696598. [PMID: 23509612 PMCID: PMC3590788 DOI: 10.1155/2013/696598] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Accepted: 01/09/2013] [Indexed: 01/13/2023] Open
Abstract
Animal studies suggest that renal tissue hypoxia plays an important role in the development of renal damage in hypertension and renal diseases, yet human data were scarce due to the lack of noninvasive methods. Over the last decade, blood oxygenation level-dependent magnetic resonance imaging (BOLD-MRI), detecting deoxyhemoglobin in hypoxic renal tissue, has become a powerful tool to assess kidney oxygenation noninvasively in humans. This paper provides an overview of BOLD-MRI studies performed in patients suffering from essential hypertension or chronic kidney disease (CKD). In line with animal studies, acute changes in cortical and medullary oxygenation have been observed after the administration of medication (furosemide, blockers of the renin-angiotensin system) or alterations in sodium intake in these patient groups, underlining the important role of renal sodium handling in kidney oxygenation. In contrast, no BOLD-MRI studies have convincingly demonstrated that renal oxygenation is chronically reduced in essential hypertension or in CKD or chronically altered after long-term medication intake. More studies are required to clarify this discrepancy and to further unravel the role of renal oxygenation in the development and progression of essential hypertension and CKD in humans.
Collapse
|
12
|
Pruijm M, Hofmann L, Maillard M, Tremblay S, Glatz N, Wuerzner G, Burnier M, Vogt B. Effect of sodium loading/depletion on renal oxygenation in young normotensive and hypertensive men. Hypertension 2010; 55:1116-22. [PMID: 20308608 DOI: 10.1161/hypertensionaha.109.149682] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The goal of this study was to investigate the effect of sodium intake on renal tissue oxygenation in humans. To this purpose, we measured renal hemodynamics, renal sodium handling, and renal oxygenation in normotensive (NT) and hypertensive (HT) subjects after 1 week of a high-sodium and 1 week of a low-sodium diet. Renal oxygenation was measured using blood oxygen level-dependent magnetic resonance. Tissue oxygenation was determined by the measurement of R2* maps on 4 coronal slices covering both kidneys. The mean R2* values in the medulla and cortex were calculated, with a low R2* indicating a high tissue oxygenation. Ten male NT (mean age: 26.5+/-7.4 years) and 8 matched HT subjects (mean age: 28.8+/-5.7 years) were studied. Cortical R2* was not different under the 2 conditions of salt intake. Medullary R2* was significantly lower under low sodium than high sodium in both NT and HT subjects (28.1+/-0.8 versus 31.3+/-0.6 s(-1); P<0.05 in NT; and 27.9+/-1.5 versus 30.3+/-0.8 s(-1); P<0.05, in HT), indicating higher medullary oxygenation under low-sodium conditions. In NT subjects, medullary oxygenation was positively correlated with proximal reabsorption of sodium and negatively with absolute distal sodium reabsorption, but not with renal plasma flow. In HT subjects, medullary oxygenation correlated with the 24-hour sodium excretion but not with proximal or with the distal handling of sodium. These data demonstrate that dietary sodium intake influences renal tissue oxygenation, low sodium intake leading to an increased renal medullary oxygenation both in normotensive and young hypertensive subjects.
Collapse
Affiliation(s)
- Menno Pruijm
- Service of Nephrology, Centre Hospitalier Universitaire Vaudois, Rue du Bugnon 17, 1011 Lausanne, Switzerland
| | | | | | | | | | | | | | | |
Collapse
|
13
|
Ethnic differences in proximal and distal tubular sodium reabsorption are heritable in black and white populations. J Hypertens 2009; 27:606-12. [PMID: 19262228 DOI: 10.1097/hjh.0b013e32832104b1] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
BACKGROUND Segmental handling of sodium along the proximal and distal nephron might be heritable and different between black and white participants. METHODS We randomly recruited 95 nuclear families of black South African ancestry and 103 nuclear families of white Belgian ancestry. We measured the (FENa) and estimated the fractional renal sodium reabsorption in the proximal (RNaprox) and distal (RNadist) tubules from the clearances of endogenous lithium and creatinine. In multivariable analyses, we studied the relation of RNaprox and RNadist with FENa and estimated the heritability (h) of RNaprox and RNadist. RESULTS Independent of urinary sodium excretion, South Africans (n = 240) had higher RNaprox (unadjusted median, 93.9% vs. 81.0%; P < 0.001) than Belgians (n = 737), but lower RNadist (91.2% vs. 95.1%; P < 0.001). The slope of RNaprox on FENa was steeper in Belgians than in South Africans (-5.40 +/- 0.58 vs. -0.78 +/- 0.58 units; P < 0.001), whereas the opposite was true for the slope of RNadist on FENa (-3.84 +/- 0.19 vs. -13.71 +/- 1.30 units; P < 0.001). h of RNaprox and RNadist was high and significant (P < 0.001) in both countries. h was higher in South Africans than in Belgians for RNaprox (0.82 vs. 0.56; P < 0.001), but was similar for RNadist (0.68 vs. 0.50; P = 0.17). Of the filtered sodium load, black participants reabsorb more than white participants in the proximal nephron and less postproximally. CONCLUSION Segmental sodium reabsorption along the nephron is highly heritable, but the capacity for regulation in the proximal and postproximal tubules differs between whites and blacks.
Collapse
|
14
|
Affiliation(s)
- Michel Burnier
- From the Service de Néphrologie et Consultation d’Hypertension, Centre Hospitalier Universitaire Vaudois, Lausanne, Switzerland
| |
Collapse
|
15
|
Relationships among endogenous ouabain, alpha-adducin polymorphisms and renal sodium handling in primary hypertension. J Hypertens 2008; 26:914-20. [PMID: 18398333 DOI: 10.1097/hjh.0b013e3282f5315f] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE The basolateral Na pump drives renotubular reabsorption. In cultured renal cells, mutant adducins, as well as sub-nanomolar ouabain concentrations, stimulate the Na-K pump. METHODS To determine whether these factors interact and affect Na handling and blood pressure (BP) in vivo, we studied 155 untreated hypertensive patients subdivided on the basis of their plasma endogenous ouabain or alpha-adducin genotype (ADD1 Gly460Trp-rs4961). RESULTS Under basal conditions, proximal tubular reabsorption and plasma Na were higher in patients with mutated Trp ADD1 or increased endogenous ouabain (P = 0.002 and 0.05, respectively). BPs were higher in the high plasma endogenous ouabain group (P = 0.001). Following volume loading, the increment in BP (7.73 vs. 4.81 mmHg) and the slopes of the relationship between BP and Na excretion were greater [0.017 +/- 0.002 vs. 0.009 +/- 0.003 mmHg/(muEq min)] in ADD1 Trp vs. ADD1 Gly carriers (P < 0.05). BP changes were similar, whereas the slopes of the relationship between BP and Na excretion were lower [0.016 +/- 0.003 vs. 0.008 +/- 0.002 mmHg/(muEq min)] in patients with low vs. high endogenous ouabain (P < 0.05). In patients with high endogenous ouabain, volume loading increased the BP in the ADD1 Trp group but not in the Gly group (P < 0.05). Thus, patients with ADD1 Trp alleles are sensitive to salt and tubular Na reabsorption remains elevated after volume expansion. CONCLUSION With saline loading, BP changes are similar in high and low endogenous ouabain patients, whereas tubular Na reabsorption increases in the high endogenous ouabain group. Saline loading unmasks differences in renal Na handling in patients with mutant adducin or high endogenous ouabain and exposes an interaction of endogenous ouabain and Trp alleles on BP.
Collapse
|
16
|
Kulick A, Panico C, Gill P, Welch WJ. Low salt intake increases adenosine type 1 receptor expression and function in the rat proximal tubule. Am J Physiol Renal Physiol 2008; 295:F37-41. [PMID: 18480183 DOI: 10.1152/ajprenal.00061.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Adenosine mediates Na+ reabsorption in the proximal tubule (PT) and other segments by activating adenosine type 1 receptors (A1-AR). We tested the hypothesis that A1-AR in the PT is regulated by salt intake and participates in the kidney adaptation to changes in salt intake. Absolute fluid reabsorption (Jv) was measured by direct in vivo microperfusion and recollection in rats maintained on low (LS; 0.03% Na, wt/wt)-, normal (NS; 0.3% Na)-, and high-salt (HS; 3.0% Na) diets for 1 wk. The effect of microperfusion of BG9719 a highly selective inhibitor of A1-ARs or adenosine deaminase (AD), which metabolizes adenosine, was measured in each group. Jv was higher in PT from LS rats (LA: 2.8 +/- 0.2 vs. NS: 2.1 +/- 0.2 nl.min(-1).mm(-1), P < 0.001). Jv in HS rats was not different from NS. BG9719 reduced Jv in LS rats by 66 +/- 6% (LS: 2.8 +/- 0.2 vs LS+CVT: 1.3 +/- 0.3 nl.min(-1).mm(-1), P < 0.001), which was greater than its effect in NS (45 +/- 4%) or HS (41 +/- 4%) rats. AD reduced Jv similarly, suggesting that A1-ARs are activated by local production of adenosine. Expression of A1-AR mRNA and protein was higher (P < 0.01) in microdissected PTs in LS rats compared with NS and HS. We conclude that A1-ARs in the PT are increased by low salt intake and that A1-AR participates in the increased PT reabsorption of solute and fluid in response to low salt intake.
Collapse
Affiliation(s)
- Aaron Kulick
- Department of Medicine, Division of Nephrology and Hypertension, Georgetown University, Washington, DC 20057, USA
| | | | | | | |
Collapse
|
17
|
de Boer MP, Ijzerman RG, de Jongh RT, Eringa EC, Stehouwer CDA, Smulders YM, Serné EH. Birth weight relates to salt sensitivity of blood pressure in healthy adults. Hypertension 2008; 51:928-32. [PMID: 18287343 DOI: 10.1161/hypertensionaha.107.101881] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The association between birth weight and blood pressure is well established but at present unexplained. According to the Borst-Guyton concept, chronic hypertension can occur only with a shift in the renal pressure-natriuresis relationship resulting in increased salt sensitivity of blood pressure. We assessed salt sensitivity of blood pressure in a group of 27 healthy adults whose birth weight was available. Birth weight was ascertained from birth certificates or announcements. Salt sensitivity of blood pressure was determined as difference in mean arterial pressure (MAP) between a 1-week high-salt ( approximately 235 mmol NaCl/d) versus low-salt diet ( approximately 55 mmol NaCl/d). Creatinine clearance was estimated according to the formula of Cockcroft and Gault. Birth weight was negatively associated with salt sensitivity of blood pressure (r=-0.60, P=0.002). The creatinine clearance was positively associated with birth weight (r=0.53; P=0.008) but did not influence the association between birth weight and salt sensitivity of blood pressure. Birth weight is associated with salt sensitivity of blood pressure, and this may play a role in the maintenance of elevated blood pressure in individuals with a low birth weight.
Collapse
Affiliation(s)
- Michiel P de Boer
- Department of Internal Medicine, Institute for Cardiovascular Research-Vrije Universiteit, University Medical Center Amsterdam, The Netherlands.
| | | | | | | | | | | | | |
Collapse
|
18
|
Affiliation(s)
- Myron H Weinberger
- Department of Medicine/Hypertension, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
| |
Collapse
|
19
|
Abstract
Dopamine plays an important role in the pathogenesis of hypertension by regulating epithelial sodium transport, vascular smooth muscle contractility and production of reactive oxygen species and by interacting with the renin–angiotensin and sympathetic nervous systems. Dopamine receptors are classified into D1-like (D1 and D5) and D2-like (D2, D3 and D4) subtypes based on their structure and pharmacology. Each of the dopamine receptor subtypes participates in the regulation of blood pressure by mechanisms specific for the subtype. Some receptors regulate blood pressure by influencing the central and/or peripheral nervous system; others influence epithelial transport and regulate the secretion and receptors of several humoral agents. This review summarizes the physiology of the different dopamine receptors in the regulation of blood pressure, and the relationship between dopamine receptor subtypes and hypertension.
Collapse
MESH Headings
- Blood Pressure/physiology
- Dopamine/metabolism
- Gastrointestinal Tract/metabolism
- Gastrointestinal Tract/physiopathology
- Humans
- Hypertension/metabolism
- Hypertension/physiopathology
- Kidney/metabolism
- Kidney/physiopathology
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/physiopathology
- Receptors, Dopamine/metabolism
- Receptors, Dopamine/physiology
- Receptors, Dopamine D1/metabolism
- Receptors, Dopamine D1/physiology
- Receptors, Dopamine D2/metabolism
- Receptors, Dopamine D2/physiology
- Receptors, Dopamine D3/metabolism
- Receptors, Dopamine D3/physiology
- Receptors, Dopamine D4/metabolism
- Receptors, Dopamine D4/physiology
- Receptors, Dopamine D5/metabolism
- Receptors, Dopamine D5/physiology
Collapse
Affiliation(s)
- Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing City, People's Republic of China.
| | | | | | | | | |
Collapse
|
20
|
Abstract
Nondrug therapy of hypertension really does work but requires strong motivation by both patient and physician. In addition to global health benefits, prescription of weight loss, exercise, moderation of salt and alcohol intake, Dietary Approach to Stop Hypertension (DASH) eating plan, and tobacco avoidance can decrease the risk for normotensive and prehypertensive patients of developing fixed hypertension. Initiating and maintaining a healthy lifestyle may be sufficient to avoid pharmacologic therapy for some patients and is a valuable adjunct to drug therapy for most. Blood pressure lowering can be achieved by weight reduction (5-20 mm Hg/10 kg), DASH eating plan (8-14 mm Hg), dietary sodium reduction (2-8 mm Hg), increased physical activity (4-9 mm Hg), and moderation of alcohol consumption (2-4 mm Hg). Combination of two or more modalities may have an additive benefit. Cessation of tobacco abuse not only has global health benefits, but may reduce blood pressure.
Collapse
Affiliation(s)
- Thor Tejada
- University of Miami OPPRP, PO Box 016960, Miami, FL 33101, USA
| | | | | | | |
Collapse
|
21
|
Messerli F, Mancia G, Conti C, Hewkin A, Kupfer S, Champion A, Kolloch R, Benetos A, Pepine C. Lowering of Blood Pressure—The Lower, the Better? J Am Soc Nephrol 2006. [DOI: 10.1681/asn.2006070776] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
|
22
|
Affiliation(s)
- Amit Sachdeva
- University of Michigan Medical School, Department of Internal Medicine, Division of Cardiovascular Medicine, 24 Frank Lloyd Wright Dr, Lobby M, Box 322, Ann Arbor, MI 48106, USA
| | | |
Collapse
|