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Arkhipov SN, Liao TD, Potter DL, Bobbitt KR, Ivanov V, Ortiz PA, Pavlov TS. Dissociation of Hypertension and Renal Damage After Cessation of High-Salt Diet in Dahl Rats. Hypertension 2024; 81:1345-1355. [PMID: 38618734 PMCID: PMC11096017 DOI: 10.1161/hypertensionaha.123.21887] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Accepted: 03/29/2024] [Indexed: 04/16/2024]
Abstract
BACKGROUND Every year, thousands of patients with hypertension reduce salt consumption in an effort to control their blood pressure. However, hypertension has a self-sustaining character in a significant part of the population. We hypothesized that chronic hypertension leads to irreversible renal damage that remains after removing the trigger, causing an elevation of the initial blood pressure. METHODS Dahl salt-sensitive rat model was used for chronic, continuous observation of blood pressure. Rats were fed a high salt diet to induce hypertension, and then the diet was switched back to normal sodium content. RESULTS We found that developed hypertension was irreversible by salt cessation: after a short period of reduction, blood pressure grew even higher than in the high-salt phase. Notably, the self-sustaining phase of hypertension was sensitive to benzamil treatment due to sustaining epithelial sodium channel hyperactivity, as shown with patch-clamp analysis. Glomerular damage and proteinuria were also irreversible. In contrast, some mechanisms, contributing to the development of salt-sensitive hypertension, normalized after salt restriction. Thus, flow cytometry demonstrated that dietary salt reduction in hypertensive animals decreased the number of total CD45+, CD3+CD4+, and CD3+CD8+ cells in renal tissues. Also, we found tubular recovery and improvement of glomerular filtration rate in the postsalt period versus a high-salt diet. CONCLUSIONS Based on earlier publications and current data, poor response to salt restriction is due to the differential contribution of the factors recognized in the developmental phase of hypertension. We suggest that proteinuria or electrolyte transport can be prioritized over therapeutic targets of inflammatory response.
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Affiliation(s)
- Sergey N. Arkhipov
- Division of Hypertension and Vascular Research, Henry Ford Health
- Department of Physiology, Wayne State University
| | - Tang-Dong Liao
- Division of Hypertension and Vascular Research, Henry Ford Health
| | - D'Anna L. Potter
- Division of Hypertension and Vascular Research, Henry Ford Health
| | | | - Veniamin Ivanov
- Division of Hypertension and Vascular Research, Henry Ford Health
| | - Pablo A. Ortiz
- Division of Hypertension and Vascular Research, Henry Ford Health
- Department of Physiology, Wayne State University
| | - Tengis S. Pavlov
- Division of Hypertension and Vascular Research, Henry Ford Health
- Department of Physiology, Wayne State University
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Shimada S, Hoffmann BR, Yang C, Kurth T, Greene AS, Liang M, Dash RK, Cowley AW. Metabolic Responses of Normal Rat Kidneys to a High Salt Intake. FUNCTION 2023; 4:zqad031. [PMID: 37575482 PMCID: PMC10413938 DOI: 10.1093/function/zqad031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 06/06/2023] [Accepted: 06/12/2023] [Indexed: 08/15/2023] Open
Abstract
In this study, novel methods were developed, which allowed continuous (24/7) measurement of arterial blood pressure and renal blood flow in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O2 and metabolites. Specifically, the study determined the effects of a high salt (HS; 4.0% NaCl) diet upon whole kidney O2 consumption and arterial and renal venous plasma metabolomic profiles of normal Sprague-Dawley rats. A separate group of rats was studied to determine changes in the cortex and outer medulla tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to 4.0% NaCl diet. In addition, targeted mRNA expression analysis of cortical segments was performed. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. A novel finding was the increased expression of glycolysis-related genes in Cx and isolated proximal tubular segments in response to an HS diet, consistent with increased release of pyruvate and lactate from the kidney to the renal venous blood. Data suggests that aerobic glycolysis (eg, Warburg effect) may contribute to energy production under these circumstances. The study provides evidence that kidney metabolism responds to an HS diet enabling enhanced energy production while protecting from oxidative stress and injury. Metabolomic and transcriptomic analysis of kidneys of Sprague-Dawley rats fed a high salt diet.
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Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Brian R Hoffmann
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Andrew S Greene
- Mass Spectrometry and Protein Chemistry, Protein Sciences, The Jackson Laboratory, Bar Harbor, ME 04609, USA
| | - Mingyu Liang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Ranjan K Dash
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
- Department of Biomedical Engineering, Medical College of Wisconsin and Marquette University, Milwaukee, WI 53226, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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Shimada S, Hoffmann BR, Yang C, Kurth T, Greene AS, Liang M, Dash RK, Cowley AW. Metabolic responses of normal rat kidneys to a high salt intake. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524636. [PMID: 36711564 PMCID: PMC9882299 DOI: 10.1101/2023.01.18.524636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In the present study, novel methods were developed which allowed continuous (24/7) measurement of blood pressure (BP) and renal blood flow (RBF) in freely moving rats and the intermittent collection of arterial and renal venous blood to estimate kidney metabolic fluxes of O 2 and metabolites. The study determined the effects of a high salt (HS) diet upon whole kidney O 2 consumption and the metabolomic profiles of normal Sprague Dawley (SD) rats. A separate group of rats was studied to determine changes in the cortex (Cx) and outer medulla (OM) tissue metabolomic and mRNAseq profiles before and following the switch from a 0.4% to a 4.0% NaCl diet. Significant changes in the metabolomic and transcriptomic profiles occurred with feeding of the HS diet. A progressive increase of kidney O 2 consumption was found despite a reduction in expression of most of the mRNA encoding enzymes of TCA cycle. Increased glycolysis was evident with the elevation of mRNA expression encoding key glycolytic enzymes and release of pyruvate and lactate from the kidney in the renal venous blood. Glycolytic production of NADH is used in either the production of lactate or oxidized via the malate aspartate shuttle. Aerobic glycolysis (e.g., Warburg-effect) may account for the needed increase in cellular energy. The study provides evidence that kidney metabolism responds to a HS diet enabling enhanced energy production while protecting from oxidate stress and injury.
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Sakuyama A, Ogawa Y, Xu L, Komatsu M, Miura T, Namai-Takahashi A, Kohzuki M, Ito O. Effects of Exercise Training on the Renin-Angiotensin System in the Kidneys of Dahl Salt-Sensitive Rats. Med Sci Sports Exerc 2022; 54:1105-1113. [PMID: 35220367 DOI: 10.1249/mss.0000000000002901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
PURPOSE Exercise training (Ex) has antihypertensive and renal protective effects; however, the precise mechanisms remain unclear. The renal renin-angiotensin system (RAS) plays a vital role in renal function and pathology. Therefore, we investigated the effects of Ex on the renal RAS components in Dahl salt-sensitive (Dahl-S) rats. METHODS Male Dahl-S rats were divided into four groups: normal salt diet + sedentary, normal salt diet + Ex, high-salt diet (HS, 8% NaCl) + sedentary, and HS + Ex. Treadmill running was performed for 8 wk in the Ex groups. RESULTS Ex attenuated the HS-induced renal dysfunction and glomerular injury without causing blood pressure alterations. HS increased urinary excretion of both total and intact angiotensinogen. Ex decreased the HS-induced increased urinary excretion of total angiotensinogen. However, it did not change the HS-induced urinary excretion of intact angiotensinogen, indicating reduced intact angiotensinogen cleaving. Ex restored the HS-induced increased angiotensinogen and angiotensin II type 1 receptor expressions in the outer medulla and the HS-induced increased angiotensin-converting enzyme expression in the cortex. Ex restored the HS-induced decreased renin expression in the cortex and outer medulla, and the HS-induced decreased angiotensin-converting enzyme 2, angiotensin II type 2 receptor, and Mas receptor expressions in the outer medulla. CONCLUSIONS Ex attenuates HS-induced renal dysfunction, glomerular injury, and renal RAS dysregulation in Dahl-S rats.
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Affiliation(s)
| | - Yoshiko Ogawa
- Department of Sport and Medical Science, Faculty of Medical Technology, Teikyo University, Tokyo, JAPAN
| | - Lusi Xu
- Division of General Medicine and Rehabilitation, Tohoku Medical and Pharmaceutical University Faculty of Medicine, Sendai, JAPAN
| | - Miwa Komatsu
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, JAPAN
| | - Takahiro Miura
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, JAPAN
| | - Asako Namai-Takahashi
- Division of General Medicine and Rehabilitation, Tohoku Medical and Pharmaceutical University Faculty of Medicine, Sendai, JAPAN
| | - Masahiro Kohzuki
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai, JAPAN
| | - Osamu Ito
- Division of General Medicine and Rehabilitation, Tohoku Medical and Pharmaceutical University Faculty of Medicine, Sendai, JAPAN
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Shimada S, Yang C, Kurth T, Cowley AW. Divergent roles of angiotensin II upon the immediate and sustained increases of renal blood flow following unilateral nephrectomy. Am J Physiol Renal Physiol 2022; 322:F473-F485. [PMID: 35224992 PMCID: PMC8977133 DOI: 10.1152/ajprenal.00376.2021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2021] [Revised: 01/31/2022] [Accepted: 02/18/2022] [Indexed: 12/18/2022] Open
Abstract
Although the molecular and functional responses related to renal compensatory hypertrophy after unilateral nephrectomy (UNX) has been well described, many aspects of these events remain unclear. One question is how the remaining kidney senses the absence of the contralateral organ, and another is what the role of the renin-angiotensin system is in these responses. Both acute anesthetized and chronic unanesthetized experiments were performed using the angiotensin II type 1 receptor blocker losartan and the renin inhibitor aliskiren to determine the contribution of the renin-angiotensin system to immediate changes and losartan for chronic changes of renal blood flow (RBF) and the associated hypertrophic events in male Sprague-Dawley rats. Chronic experiments used implanted RBF probes and arterial catheters for continuous data collection, and the glomerular filtration rate was determined by noninvasive transcutaneous FITC-sinistrin measurements. The results of the acute experiments found that RBF increased nearly 25% (4.6 ± 0.5 to 5.6 ± 0.6 mL/min/g kidney wt) during the first 15 min following UNX and that this response was abolished by losartan (6.7 ± 0.7 to 7.0 ± 0.7 mL/min/g kidney wt) or aliskiren (5.8 ± 0.4 to 6.0 ± 0.4 mL/min/g kidney wt) treatment. Thereafter, RBF increased progressively over 7 days, and kidney weight increased by 19% of pre-UNX values. When normalized to kidney weight determined at day 7 after UNX, RBF was not significantly different from pre-UNX levels. Semiquantification of CD31-positive capillaries revealed increases of the glomeruli and peritubular capillaries that paralleled the kidney hypertrophy. None of these chronic changes was inhibited by losartan treatment, indicating that neither the compensatory structural nor the RBF changes were angiotensin II type 1 receptor dependent.NEW & NOTEWORTHY This study found that the immediate increases of renal blood flow (RBF) following unilateral nephrectomy (UNX) are a consequence of reduced angiotensin II type 1 (AT1) receptor stimulation. The continuous monitoring of RBF and intermittent measurement of glomerular filtration rate (GFR) in conscious rats during the 1-wk period of rapid hypertrophy following UNX provided unique insights into the regulation of RBF and GFR when faced with increased metabolic loads. It was found that neither kidney hypertrophy nor the associated increase of capillaries was an AT1-dependent phenomenon.
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Affiliation(s)
- Satoshi Shimada
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Theresa Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Miura T, Sakuyama A, Xu L, Qiu J, Namai-Takahashi A, Ogawa Y, Kohzuki M, Ito O. Febuxostat ameliorates high salt intake-induced hypertension and renal damage in Dahl salt-sensitive rats. J Hypertens 2022; 40:327-337. [PMID: 34495901 DOI: 10.1097/hjh.0000000000003012] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Several clinical studies have reported that xanthine oxidoreductase inhibitors have antihypertensive and renal protective effects but their mechanisms have not been fully determined. This study aims to clarify these mechanisms by examining the effects of febuxostat, which is a novel selective xanthine oxidoreductase inhibitor, in Dahl salt-sensitive rats. METHODS Eight-week-old male Dahl salt-sensitive rats were fed a normal salt (0.6% NaCl) or high salt (8% NaCl) diet for 8 weeks. A portion of the rats that were fed high salt diet were treated with febuxostat (3 mg/kg per day) simultaneously. Additionally, acute effects of febuxostat (3 mg/kg per day) were examined after high salt diet feeding for 4 or 8 weeks. RESULTS Treatment with febuxostat for 8 weeks attenuated high salt diet-induced hypertension, renal dysfunction, glomerular injury, and renal interstitial fibrosis. Febuxostat treatment reduced urinary excretion of H2O2 and malondialdehyde and renal thiobarbituric acid reactive substances content. High salt diet increased xanthine oxidoreductase activity and expression in the proximal tubules and medullary interstitium. Febuxostat completely inhibited xanthine oxidoreductase activity and attenuated the high salt diet-increased xanthine oxidoreductase expression. Febuxostat transiently increased urine volume and Na+ excretion without change in blood pressure or urinary creatinine excretion after high salt diet feeding for 4 or 8 weeks. CONCLUSION Febuxostat ameliorates high salt diet-induced hypertension and renal damage with a reduction of renal oxidative stress in Dahl salt-sensitive rats. The antihypertensive effect of febuxostat may be mediated in part by diuretic and natriuretic action.
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Affiliation(s)
- Takahiro Miura
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai
| | - Akihiro Sakuyama
- Department of Physical Therapy, Faculty of Health Science, Juntendo University, Tokyo
| | - Lusi Xu
- Division of General Medicine and Rehabilitation, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai
| | - Jiahe Qiu
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai
| | - Asako Namai-Takahashi
- Division of General Medicine and Rehabilitation, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai
| | - Yoshiko Ogawa
- Department of Sport and Medical Science, Faculty of Medical Technology, Teikyo University, Tokyo, Japan
| | - Masahiro Kohzuki
- Department of Internal Medicine and Rehabilitation Science, Tohoku University Graduate School of Medicine, Sendai
| | - Osamu Ito
- Division of General Medicine and Rehabilitation, Faculty of Medicine, Tohoku Medical and Pharmaceutical University, Sendai
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Ling XX, Chen H, Fu BB, Ruan CS, Pana M, Zhou K, Fang ZR, Shao JT, Zhu FQ, Gao S. Xin-Ji-Er-Kang protects myocardial and renal injury in hypertensive heart failure in mice. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2021; 91:153675. [PMID: 34332285 DOI: 10.1016/j.phymed.2021.153675] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 05/27/2021] [Accepted: 07/14/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND Xin-Ji-Er-Kang (XJEK) as a herbal formula of traditional Chinese medicine (TCM) has shown the protective effects on myocardial function as well as renal function in mouse models of myocardial infarction. HYPOTHESIS/PURPOSE We investigated the effects of XJEK on cardiovascular- and renal-function in a heart failure mouse model induced by high salt (HS) and the associated mechanisms. STUDY DESIGN For the purpose of assessing the effects of XJEK on a hypertensive heart failure model, mice were fed with 8% high salt diet. XJEK was administered by oral gavage for 8 weeks. Cardiovascular function parameters, renal function associated biomarkers and XJEK's impact on renin-angiotensin-aldosterone system (RAAS) activation were assessed. To determine the underlying mechanism, the calpain1/junctophilin-2 (JP2)/sarcoplasmic reticulum Ca2+ ATPase (SERCA2a) pathway was further studied in AC16 cells after angiotensin II-challenge or after calpastatin small interfering RNA (siRNA) transfection. RESULTS Mice on HS-diet exhibited hypertensive heart failure along with progressive kidney injury. Similar to fosinopril, XJEK ameliorated hypertension, cardiovascular-and renal- dysfunction in mice of HS-diet group. XJEK inhibited HS-induced activation of RAAS and reversed the abnormal expression pattern of calpain1and JP2 protein in heart tissues. XJEK significantly improved cell viability of angiotensin II-challenged AC16 cells. Moreover, XJEK's impact on calpain1/JP2 pathway was partly diminished in AC16 cells transfected with calpastatin siRNA. CONCLUSION XJEK was found to exert cardiovascular- and renal protection in HS-diet induced heart failure mouse model. XJEK inhibited HS-diet induced RAAS activation by inhibiting the activity and expression of calpain1 and protected the junctional membrane complex (JMC) in cardiomyocytes.
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Affiliation(s)
- Xin-Xin Ling
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Hua Chen
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Bei-Bei Fu
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Cheng-Shao Ruan
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Ming Pana
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Kai Zhou
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Zhi-Rui Fang
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China
| | - Jun-Tang Shao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China.
| | - Feng-Qin Zhu
- Hefei Cancer Hospital, Chinese Academy of Science, Hefei 230032, China.
| | - Shan Gao
- Department of Pharmacology, Basic Medical College, Anhui Medical University, Hefei 230032, China.
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Abstract
Hypertension is a leading risk factor for disease burden worldwide. The kidneys, which have a high specific metabolic rate, play an essential role in the long-term regulation of arterial blood pressure. In this review, we discuss the emerging role of renal metabolism in the development of hypertension. Renal energy and substrate metabolism is characterized by several important and, in some cases, unique features. Recent advances suggest that alterations of renal metabolism may result from genetic abnormalities or serve initially as a physiological response to environmental stressors to support tubular transport, which may ultimately affect regulatory pathways and lead to unfavorable cellular and pathophysiological consequences that contribute to the development of hypertension.
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Affiliation(s)
- Zhongmin Tian
- grid.43169.390000 0001 0599 1243The Key Laboratory of Biomedical Information Engineering of Ministry of Education, School of Life Science and Technology, Xi’an Jiaotong University, Xi’an, Shaanxi China
| | - Mingyu Liang
- grid.30760.320000 0001 2111 8460Center of Systems Molecular Medicine, Department of Physiology, Medical College of Wisconsin, Milwaukee, WI USA
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Schröder K. NADPH oxidases: Current aspects and tools. Redox Biol 2020; 34:101512. [PMID: 32480354 PMCID: PMC7262010 DOI: 10.1016/j.redox.2020.101512] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/11/2020] [Accepted: 03/16/2020] [Indexed: 12/27/2022] Open
Abstract
Reactive oxygen species (ROS) have been shown or at least suggested to play an essential role for cellular signaling as second messengers. NADPH oxidases represent a source of controlled ROS formation. Accordingly, understanding the role of individual NADPH oxidases bears potential to interfere with intracellular signaling cascades without disturbing the signaling itself. Many tools have been developed to study or inhibit the functions and roles of the NADPH oxidases. This short review summarizes diseases, potentially associated with NADPH oxidases, genetically modified animals, and inhibitors.
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Affiliation(s)
- Katrin Schröder
- Institut für Kardiovaskuläre Physiologie, Fachbereich Medizin der Goethe-Universität, Theodor-Stern Kai 7, 60590, Frankfurt, Germany. https://
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Kumar V, Yang C, Cowley AW. Temporal Expression and Cellular Localization of PAPPA2 in the Developing Kidney of Rat. J Histochem Cytochem 2020; 68:209-222. [PMID: 31989854 DOI: 10.1369/0022155420904478] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
PAPPA2 is a metalloproteinase which cleaves insulin-like growth factor binding protein (IGFBP)-3 and IGFBP-5, and its role in pregnancy and postnatal growth is primarily studied. Using exclusion mapping, we reported a subcongenic (26-P) rat where a 0.71-Mbp region containing the pregnancy-associated plasma protein a2 (Pappa2) allele of salt-insensitive Brown Norway (BN) was introgressed into Dahl saltsensitive (SS) genetic background, resulting in the reduction of salt sensitivity. Pappa2 was differentially expressed in the adult kidney of 26-P and SS rats. Here, the expression and cellular localization of Pappa2 in embryonic and postnatal kidneys of 26-P and SS rats were examined. Pappa2 mRNA expression was 5-fold higher in the embryonic kidney (day 20.5) of the 26-P rat compared with the SS rat. Pappa2 mRNA expression progressively increased with the development of kidney, reaching a peak at postnatal day 5 before trending downward in subsequent stages of development in both strains. At all tested time points, Pappa2 remained higher in the 26-P compared with the SS rat kidney. Immunohistochemistry studies localized PAPPA2 in the ureteric bud (UB) and distal part of S-shaped body. PAPPA2 was colocalized with IGFBP-5 in the UB and Na+/K+/2Cl- cotransporter-stained tubules, respectively. Future studies are needed to determine the role of Pappa2 in kidney development and mechanistic pathways involved in this process.
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Affiliation(s)
- Vikash Kumar
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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Abais-Battad JM, Lund H, Dasinger JH, Fehrenbach DJ, Cowley AW, Mattson DL. NOX2-derived reactive oxygen species in immune cells exacerbates salt-sensitive hypertension. Free Radic Biol Med 2020; 146:333-339. [PMID: 31730933 PMCID: PMC6942201 DOI: 10.1016/j.freeradbiomed.2019.11.014] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/29/2019] [Accepted: 11/11/2019] [Indexed: 12/11/2022]
Abstract
Previous studies utilizing the SSp67phox-/- rat have demonstrated the importance of systemic NADPH oxidase NOX2-derived reactive oxygen species (ROS) production in the pathogenesis of Dahl Salt-Sensitive (SS) hypertension and renal damage. It is established that the immune system contributes to the development of SS hypertension and our laboratory has observed an enrichment of NOX2 subunits in infiltrating T cells. However, the contribution of immune cell-derived ROS in SS hypertension remains unknown. To assess the role of ROS in immune cells, SSp67phox-/- rats underwent total body irradiation and received bone marrow transfer from either SS (+SS) or SSp67phox-/- (+SSp67phox-/-) donor rats. Demonstrated in a respiratory burst assay, response to phorbol 12-myristate 13-acetate stimulus (135 μM) was 10.2-fold greater in peritoneal macrophages isolated from +SS rats compared to nonresponsive + SSp67phox-/- cells, validating that + SS rats were capable of producing NOX2-derived ROS in cells of hematopoietic origin. After 3 weeks of high salt challenge, there was an exacerbated increase in mean arterial pressure in +SS rats compared to + SSp67phox-/- control rats (176.1 ± 4.7 vs 147.9 ± 8.4 mmHg, respectively), which was accompanied by a significant increase in albuminuria (168.3 ± 23.7 vs 107.0 ± 20.4 mg/day) and renal medullary protein cast formation (33.2 ± 4.7 vs 8.1 ± 3.5%). Interestingly, upon analysis of renal immune cells, there was trending increase of CD11b/c + monocytes and macrophages in the kidney of +SS rats (4.7 ± 0.4 vs 3.5 ± 0.5 × 106 cells/kidney, +SS vs + SSp67phox-/-, p = 0.06). These data altogether demonstrate that immune cell production of NOX2-derived ROS is sufficient to exacerbate Dahl SS hypertension, renal damage, and renal inflammation.
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Affiliation(s)
- Justine M Abais-Battad
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA.
| | - Hayley Lund
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - John Henry Dasinger
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Daniel J Fehrenbach
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - Allen W Cowley
- Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
| | - David L Mattson
- Department of Physiology, Medical College of Wisconsin, Milwaukee, WI, USA; Department of Physiology, Medical College of Georgia at Augusta University, Augusta, GA, USA
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Gonzalez-Vicente A, Hong N, Garvin JL. Effects of reactive oxygen species on renal tubular transport. Am J Physiol Renal Physiol 2019; 317:F444-F455. [PMID: 31215804 DOI: 10.1152/ajprenal.00604.2018] [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: 02/07/2023] Open
Abstract
Reactive oxygen species (ROS) play a critical role in regulating nephron transport both via transcellular and paracellular pathways under physiological and pathological circumstances. Here, we review the progress made in the past ~10 yr in understanding how ROS regulate solute and water transport in individual nephron segments. Our knowledge in this field is still rudimentary, with basic information lacking. This is most obvious when looking at the reported disparate effects of superoxide ([Formula: see text]) and H2O2 on proximal nephron transport, where there are no easy explanations as to how to reconcile the data. Similarly, we know almost nothing about the regulation of transport in thin descending and ascending limbs, information that is likely critical to understanding the urine concentrating mechanism. In the thick ascending limb, there is general agreement that ROS enhance transcellular reabsorption of NaCl, but we know very little about their effects on the paracellular pathway and therefore Ca2+ and Mg2+ transport. In the distal convoluted tubule, precious little is known. In the collecting duct, there is general agreement that ROS stimulate the epithelial Na+ channel.
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Affiliation(s)
- Agustin Gonzalez-Vicente
- Department of Inflammation and Immunity, Cleveland Clinic, Lerner Research Institute, Cleveland, Ohio
| | - Nancy Hong
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University Cleveland, Ohio
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Massaro M, Scoditti E, Carluccio MA, De Caterina R. Oxidative stress and vascular stiffness in hypertension: A renewed interest for antioxidant therapies? Vascul Pharmacol 2019; 116:45-50. [PMID: 30946986 DOI: 10.1016/j.vph.2019.03.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Since the first successful launch of the Veterans Administration(VA) cooperative studies in the late 1960s, the increasing access to blood pressure lowering medications has significantly contributed to improving longevity and quality of life in hypertensive patients. Since then, insights into the pathogenesis of hypertension have shown a mechanistic role for reactive oxygen species (ROS) in all phases of disease progression, suggesting the potential utility of antioxidant therapies to counteract symptoms and, at the same time, treat a fundamental mechanism of the disease. Despite these progresses, hypertension still remains the main contributor to the global incidence of cardiovascular disease and the leading cause of morbidity and mortality worldwide. We here briefly review and update the role of ROS and ROS-dependent metalloproteinase activation in the maladaptive remodeling of the vascular wall in hypertension. Such understanding should provide new Potential sites of action for antioxidant therapies as an integrated therapeutic approach to hypertension and its consequences.
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Affiliation(s)
- Marika Massaro
- National Research Council (CNR) Institute of Clinical Physiology, Lecce, Italy
| | - Egeria Scoditti
- National Research Council (CNR) Institute of Clinical Physiology, Lecce, Italy
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14
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Regal JF, Laule CF, McCutcheon L, Root KM, Lund H, Hashmat S, Mattson DL. The complement system in hypertension and renal damage in the Dahl SS rat. Physiol Rep 2019; 6:e13655. [PMID: 29595916 PMCID: PMC5875537 DOI: 10.14814/phy2.13655] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 02/25/2018] [Accepted: 02/26/2018] [Indexed: 11/24/2022] Open
Abstract
Evidence indicates the immune system is important in development of hypertension and kidney disease. In the Dahl Salt-Sensitive (SS) rat model, lymphocytes play a role in development of hypertension and kidney damage after increased sodium intake. Recent transcriptomic analyses demonstrate upregulation of the innate immune complement system in the kidney of Dahl SS rat fed a high-salt diet, leading us to hypothesize that inhibition of complement activation would attenuate development of hypertension and kidney damage. Male Dahl SS rats on a low salt (0.4% NaCl) diet were instrumented with telemeters for continuous monitoring of arterial blood pressure. Animals received saline vehicle (Control) or sCR1, a soluble form of endogenous Complement Receptor 1 (CR1; CD35) that inhibits complement activation. At Day 0, rats were switched to high salt (4.0% NaCl) diet and assigned to sCR1 (15 mg/kg per day) or Control groups with daily ip injections either days 1-7 or days 14-18. Urine was collected overnight for determination of albumin excretion. Treatment with sCR1, either immediately after high-salt diet was initiated, or at days 14-18, did not alter development of hypertension or albuminuria. The sCR1 dose effectively inhibited total hemolytic complement activity as well as C3a generation. High salt caused an increase in message for complement regulator Cd59, with minimal change in Crry that controls the C3 convertase. Thus, innate immune complement activation in the circulation is not critical for development of hypertension and kidney damage due to increased sodium intake, and therapeutic manipulation of the complement system is not indicated in salt-sensitive hypertension.
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Affiliation(s)
- Jean F Regal
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, Minnesota
| | - Connor F Laule
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, Minnesota
| | - Luke McCutcheon
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, Minnesota
| | - Kate M Root
- Department of Biomedical Sciences, University of Minnesota Medical School, Duluth Campus, Duluth, Minnesota
| | - Hayley Lund
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Shireen Hashmat
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - David L Mattson
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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15
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Gonzalez-Vicente A, Saez F, Monzon CM, Asirwatham J, Garvin JL. Thick Ascending Limb Sodium Transport in the Pathogenesis of Hypertension. Physiol Rev 2019; 99:235-309. [PMID: 30354966 DOI: 10.1152/physrev.00055.2017] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The thick ascending limb plays a key role in maintaining water and electrolyte balance. The importance of this segment in regulating blood pressure is evidenced by the effect of loop diuretics or local genetic defects on this parameter. Hormones and factors produced by thick ascending limbs have both autocrine and paracrine effects, which can extend prohypertensive signaling to other structures of the nephron. In this review, we discuss the role of the thick ascending limb in the development of hypertension, not as a sole participant, but one that works within the rich biological context of the renal medulla. We first provide an overview of the basic physiology of the segment and the anatomical considerations necessary to understand its relationship with other renal structures. We explore the physiopathological changes in thick ascending limbs occurring in both genetic and induced animal models of hypertension. We then discuss the racial differences and genetic defects that affect blood pressure in humans through changes in thick ascending limb transport rates. Throughout the text, we scrutinize methodologies and discuss the limitations of research techniques that, when overlooked, can lead investigators to make erroneous conclusions. Thus, in addition to advancing an understanding of the basic mechanisms of physiology, the ultimate goal of this work is to understand our research tools, to make better use of them, and to contextualize research data. Future advances in renal hypertension research will require not only collection of new experimental data, but also integration of our current knowledge.
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Affiliation(s)
| | - Fara Saez
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Casandra M Monzon
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jessica Asirwatham
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
| | - Jeffrey L Garvin
- Department of Physiology and Biophysics, Case Western Reserve University , Cleveland, Ohio
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16
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Bukowy JD, Dayton A, Cloutier D, Manis AD, Staruschenko A, Lombard JH, Solberg Woods LC, Beard DA, Cowley AW. Region-Based Convolutional Neural Nets for Localization of Glomeruli in Trichrome-Stained Whole Kidney Sections. J Am Soc Nephrol 2018; 29:2081-2088. [PMID: 29921718 PMCID: PMC6065078 DOI: 10.1681/asn.2017111210] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2017] [Accepted: 05/17/2018] [Indexed: 12/12/2022] Open
Abstract
Background Histologic examination of fixed renal tissue is widely used to assess morphology and the progression of disease. Commonly reported metrics include glomerular number and injury. However, characterization of renal histology is a time-consuming and user-dependent process. To accelerate and improve the process, we have developed a glomerular localization pipeline for trichrome-stained kidney sections using a machine learning image classification algorithm.Methods We prepared 4-μm slices of kidneys from rats of various genetic backgrounds that were subjected to different experimental protocols and mounted the slices on glass slides. All sections used in this analysis were trichrome stained and imaged in bright field at a minimum resolution of 0.92 μm per pixel. The training and test datasets for the algorithm comprised 74 and 13 whole renal sections, respectively, totaling over 28,000 glomeruli manually localized. Additionally, because this localizer will be ultimately used for automated assessment of glomerular injury, we assessed bias of the localizer for preferentially identifying healthy or damaged glomeruli.Results Localizer performance achieved an average precision and recall of 96.94% and 96.79%, respectively, on whole kidney sections without evidence of bias for or against glomerular injury or the need for manual preprocessing.Conclusions This study presents a novel and robust application of convolutional neural nets for the localization of glomeruli in healthy and damaged trichrome-stained whole-renal section mounts and lays the groundwork for automated glomerular injury scoring.
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Affiliation(s)
- John D Bukowy
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Alex Dayton
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Dustin Cloutier
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Anna D Manis
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | | | - Julian H Lombard
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Leah C Solberg Woods
- Molecular Medicine, Wake Forest University School of Medicine, Winston-Salem, North Carolina; and
| | - Daniel A Beard
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin;
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17
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Togliatto G, Lombardo G, Brizzi MF. The Future Challenge of Reactive Oxygen Species (ROS) in Hypertension: From Bench to Bed Side. Int J Mol Sci 2017; 18:ijms18091988. [PMID: 28914782 PMCID: PMC5618637 DOI: 10.3390/ijms18091988] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Revised: 09/07/2017] [Accepted: 09/13/2017] [Indexed: 02/07/2023] Open
Abstract
Reactive oxygen species (ROS) act as signaling molecules that control physiological processes, including cell adaptation to stress. Redox signaling via ROS has quite recently become the focus of much attention in numerous pathological contexts, including neurodegenerative diseases, kidney and cardiovascular disease. Imbalance in ROS formation and degradation has also been implicated in essential hypertension. Essential hypertension is characterized by multiple genetic and environmental factors which do not completely explain its associated risk factors. Thereby, even if advances in therapy have led to a significant reduction in hypertension-associated complications, to interfere with the unbalance of redox signals might represent an additional therapeutic challenge. The decrease of nitric oxide (NO) levels, the antioxidant activity commonly found in preclinical models of hypertension and the ability of antioxidant approaches to reduce ROS levels have spurred clinicians to investigate the contribution of ROS in humans. Indeed, particular effort has recently been devoted to understanding how redox signaling may contribute to vascular pathobiology in human hypertension. However, although biomarkers of oxidative stress have been found to positively correlate with blood pressure in preclinical model of hypertension, human data are less convincing. We herein provide an overview of the most relevant mechanisms via which oxidative stress might contribute to the pathophysiology of essential hypertension. Moreover, alternative approaches, which are directed towards improving antioxidant machinery and/or interfering with ROS production, are also discussed.
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Affiliation(s)
- Gabriele Togliatto
- Department of Medical Sciences, University of Torino, 10126 Torino, Italy.
| | - Giusy Lombardo
- Department of Medical Sciences, University of Torino, 10126 Torino, Italy.
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18
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Schröder K, Weissmann N, Brandes RP. Organizers and activators: Cytosolic Nox proteins impacting on vascular function. Free Radic Biol Med 2017; 109:22-32. [PMID: 28336130 DOI: 10.1016/j.freeradbiomed.2017.03.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2017] [Revised: 02/24/2017] [Accepted: 03/14/2017] [Indexed: 01/25/2023]
Abstract
NADPH oxidases of the Nox family are important enzymatic sources of reactive oxygen species (ROS) in the cardiovascular system. Of the 7 members of the Nox family, at least three depend for their activation on specific cytosolic proteins. These are p47phox and its homologue NoxO1 and p67phox and its homologue NoxA1. Also the Rho-GTPase Rac is important but as this protein has many additional functions, it will not be covered here. The Nox1 enzyme is preferentially activated by the combination of NoxO1 with NoxA1, whereas Nox2 gains highest activity with p47phox together with p67phox. As p47phox, different to NoxO1 contains an auto inhibitory region it has to be phosphorylated prior to complex formation. In the cardio-vascular system, all cytosolic Nox proteins are expressed but the evidence for their contribution to ROS production is not well established. Most data have been collected for p47phox, whereas NoxA1 has basically not yet been studied. In this article the specific aspects of cytosolic Nox proteins in the cardiovascular system with respect to Nox activation, their expression and their importance will be reviewed. Finally, it will be discussed whether cytosolic Nox proteins are suitable pharmacological targets to tamper with vascular ROS production.
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Affiliation(s)
- Katrin Schröder
- Institut für Kardiovaskuläre Physiologie, Goethe-Universität Frankfurt, Frankfurt, Germany.
| | - Norbert Weissmann
- Excellence Cluster Cardiopulmonary System, University of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Justus-Liebig-University, 35392 Giessen, Germany
| | - Ralf P Brandes
- Institut für Kardiovaskuläre Physiologie, Goethe-Universität Frankfurt, Frankfurt, Germany
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19
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Frame AA, Wainford RD. Renal sodium handling and sodium sensitivity. Kidney Res Clin Pract 2017; 36:117-131. [PMID: 28680820 PMCID: PMC5491159 DOI: 10.23876/j.krcp.2017.36.2.117] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2016] [Accepted: 12/27/2016] [Indexed: 01/11/2023] Open
Abstract
The pathophysiology of hypertension, which affects over 1 billion individuals worldwide, involves the integration of the actions of multiple organ systems, including the kidney. The kidney, which governs sodium excretion via several mechanisms including pressure natriuresis and the actions of renal sodium transporters, is central to long term blood pressure regulation and the salt sensitivity of blood pressure. The impact of renal sodium handling and the salt sensitivity of blood pressure in health and hypertension is a critical public health issue owing to the excess of dietary salt consumed globally and the significant percentage of the global population exhibiting salt sensitivity. This review highlights recent advances that have provided new insight into the renal handling of sodium and the salt sensitivity of blood pressure, with a focus on genetic, inflammatory, dietary, sympathetic nervous system and oxidative stress mechanisms that influence renal sodium excretion. Increased understanding of the multiple integrated mechanisms that regulate the renal handling of sodium and the salt sensitivity of blood pressure has the potential to identify novel therapeutic targets and refine dietary guidelines designed to treat and prevent hypertension.
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Affiliation(s)
- Alissa A Frame
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
| | - Richard D Wainford
- Department of Pharmacology & Experimental Therapeutics and The Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA, USA
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20
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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: 11] [Impact Index Per Article: 1.6] [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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21
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Hilliard LM, Denton KM. Transcutaneous assessment of glomerular filtration rate in unanesthetized rats using a small animal imager: impact on arterial pressure, heart rate, and activity. Physiol Rep 2016. [PMCID: PMC5064127 DOI: 10.14814/phy2.12723] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Affiliation(s)
- Lucinda M. Hilliard
- Cardiovascular Program; Monash Biomedicine Discovery Institute and Departments of Physiology; Monash University; Melbourne Victoria 3800 Australia
| | - Kate M. Denton
- Cardiovascular Program; Monash Biomedicine Discovery Institute and Departments of Physiology; Monash University; Melbourne Victoria 3800 Australia
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22
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Hilliard LM, Colafella KMM, Bulmer LL, Puelles VG, Singh RR, Ow CPC, Gaspari T, Drummond GR, Evans RG, Vinh A, Denton KM. Chronic recurrent dehydration associated with periodic water intake exacerbates hypertension and promotes renal damage in male spontaneously hypertensive rats. Sci Rep 2016; 6:33855. [PMID: 27653548 PMCID: PMC5032121 DOI: 10.1038/srep33855] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 09/05/2016] [Indexed: 01/12/2023] Open
Abstract
Epidemiological evidence links recurrent dehydration associated with periodic water intake with chronic kidney disease (CKD). However, minimal attention has been paid to the long-term impact of periodic water intake on the progression of CKD and underlying mechanisms involved. Therefore we investigated the chronic effects of recurrent dehydration associated with periodic water restriction on arterial pressure and kidney function and morphology in male spontaneously hypertensive rats (SHR). Arterial pressure increased and glomerular filtration rate decreased in water-restricted SHR. This was observed in association with cyclic changes in urine osmolarity, indicative of recurrent dehydration. Additionally, water-restricted SHR demonstrated greater renal fibrosis and an imbalance in favour of pro-inflammatory cytokine-producing renal T cells compared to their control counterparts. Furthermore, urinary NGAL levels were greater in water-restricted than control SHR. Taken together, our results provide significant evidence that recurrent dehydration associated with chronic periodic drinking hastens the progression of CKD and hypertension, and suggest a potential role for repetitive bouts of acute renal injury driving renal inflammatory processes in this setting. Further studies are required to elucidate the specific pathways that drive the progression of recurrent dehydration-induced kidney disease.
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Affiliation(s)
- Lucinda M Hilliard
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Katrina M Mirabito Colafella
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Louise L Bulmer
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Victor G Puelles
- Department of Anatomy and Developmental Biology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Reetu R Singh
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Connie P C Ow
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Tracey Gaspari
- Department of Pharmacology, Monash University, Melbourne, Victoria, 3800 Australia
| | - Grant R Drummond
- Department of Pharmacology, Monash University, Melbourne, Victoria, 3800 Australia
| | - Roger G Evans
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
| | - Antony Vinh
- Department of Pharmacology, Monash University, Melbourne, Victoria, 3800 Australia
| | - Kate M Denton
- Cardiovascular Disease Program, Biomedicine Discovery Institute and Department of Physiology, Monash University, Melbourne, Victoria, 3800, Australia
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23
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Improved kinetic model for the transcutaneous measurement of glomerular filtration rate in experimental animals. Kidney Int 2016; 90:1377-1385. [PMID: 27665115 DOI: 10.1016/j.kint.2016.07.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Revised: 07/13/2016] [Accepted: 07/14/2016] [Indexed: 02/06/2023]
Abstract
Transcutaneous measurement of the glomerular filtration rate (tGFR) is now frequently used in animal studies. tGFR allows consecutive measurements on the same animal, including multiple measurements on a daily basis, because no blood sampling is required. Here we derive and validate a novel kinetic model for the description of transcutaneously measured FITC-Sinistrin excretion kinetics. In contrast to standard 1- to 3-compartment models, our model covers the complete kinetic, including injection and distribution of the tracer in the plasma compartment. Because the model describes the complete progression of the measurement, it allows further refinement by correcting for baseline shifts observed occasionally during measurement. Possible reasons for shifts in the background signal include photo bleaching of the skin, autofluorescence, changes of physiological state of the animals during the measurements, or effects arising from the attachment of the measurement device. Using the new 3-compartment kinetic model with modulated baseline (tGFR3cp.b.m), tGFR measurements in rats can reach comparable precision as those from GFR measurements assessed using a gold standard technique based on constant infusion of a tracer. Moreover, the variability of simultaneous (parallel) measurements, as well as repeated tGFR measurements in the same animals, showed higher precision when tGFR3cp.b.m was compared with the 1-compartment tGFR1cp model.
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24
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Elijovich F, Weinberger MH, Anderson CAM, Appel LJ, Bursztyn M, Cook NR, Dart RA, Newton-Cheh CH, Sacks FM, Laffer CL. Salt Sensitivity of Blood Pressure: A Scientific Statement From the American Heart Association. Hypertension 2016; 68:e7-e46. [PMID: 27443572 DOI: 10.1161/hyp.0000000000000047] [Citation(s) in RCA: 301] [Impact Index Per Article: 37.6] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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25
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Zheleznova NN, Yang C, Cowley AW. Role of Nox4 and p67phox subunit of Nox2 in ROS production in response to increased tubular flow in the mTAL of Dahl salt-sensitive rats. Am J Physiol Renal Physiol 2016; 311:F450-8. [PMID: 27279484 DOI: 10.1152/ajprenal.00187.2016] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Accepted: 06/03/2016] [Indexed: 11/22/2022] Open
Abstract
Nox4 and Nox2 are the most abundant NADPH oxidases (Nox) in the kidney and have been shown to contribute to hypertension, renal oxidative stress, and injury in Dahl salt-sensitive (SS) hypertensive rats. The present study focused on the role of Nox4 and p67phox/Nox2 in the generation of H2O2 and O2 (·-) in the renal medullary thick ascending limb of Henle (mTAL) of SS rats in response to increasing luminal flow (from 5 to 20 nl/min). Nox4 and p67phox/Nox2 genes were found to be expressed in the mTAL of SS rats. Responses of SS rats were compared with those of SS rats with knockout of Nox4 (SS(Nox4-/-)) or functional mutation of p67phox (SS(p67phox-/-)). Nox4 was the dominant source of increased intracellular H2O2 production in response to increased luminal flow as determined using the fluorescent dye peroxyfluor 6-AM (PF6-AM). The rate of mitochondrial H2O2 production [as determined by mitochondria peroxy yellow 1 (mitoPY1)] was also significantly reduced in SS(Nox4-/-) compared with SS rats, but not in SS(p67phox-/-) rats. In contrast, intracellular superoxide (O2 (·-)) production (the ratio of ethidium to dihydroethidium) in the mTAL of SS(Nox4-/-) rats was nearly identical to that of SS rats in response to luminal flow, indicating that Nox4 made no measurable contribution. mTAL O2 (·-) production was reduced in SS(p67phox-/-) compared with SS rats at the lower luminal flow of 5 nl/min and progressively increased when perfusion was changed to 20 nl/min. We conclude that increased mTAL luminal flow results in increases in intracellular and mitochondrial H2O2, which are dependent on the presence of Nox4, and that p67phox/Nox2 accounts solely for increases in O2 (·-) production.
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Affiliation(s)
| | - Chun Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - Allen W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
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26
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O'Connor PM, Guha A, Stilphen CA, Sun J, Jin C. Proton channels and renal hypertensive injury: a key piece of the Dahl salt-sensitive rat puzzle? Am J Physiol Regul Integr Comp Physiol 2016; 310:R679-90. [PMID: 26843580 DOI: 10.1152/ajpregu.00115.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2015] [Accepted: 01/25/2016] [Indexed: 02/07/2023]
Abstract
Hv1 is a voltage-gated proton channel highly expressed in phagocytic cells, where it participates in the NADPH oxidase-dependent respiratory burst. We have recently identified Hv1 as a novel renal channel, expressed in the renal medullary thick ascending limb that appears to importantly contribute to the pathogenesis of renal hypertensive injury in the Dahl salt-sensitive rat model. The purpose of this review is to describe the experimental approaches that we have undertaken to identify the source of excess reactive oxygen species production in the renal outer medulla of Dahl salt-sensitive rats and the resulting evidence that the voltage-gated proton channel Hv1 mediates augmented superoxide production and contributes to renal medullary oxidative stress and renal injury. In addition, we will attempt to point out areas of current controversy, as well as propose areas in which further experimental studies are likely to move the field forward. The content of the following review was presented as part of the Water and Electrolyte Homeostasis Section New Investigator Award talk at Experimental Biology 2014.
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Affiliation(s)
- Paul M O'Connor
- Department of Physiology, Augusta University, Augusta, Georgia; and
| | - Avirup Guha
- Department of Physiology, Augusta University, Augusta, Georgia; and
| | - Carly A Stilphen
- Department of Physiology, Augusta University, Augusta, Georgia; and
| | - Jingping Sun
- Department of Physiology, Augusta University, Augusta, Georgia; and
| | - Chunhua Jin
- Department of Medicine, Division of Nephrology, University of Alabama at Birmingham, Birmingham, Alabama
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27
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Shmarlouski A, Schock-Kusch D, Shulhevich Y, Buschmann V, Rohlicke T, Herdt D, Radle M, Hesser J, Stsepankou D. A Novel Analysis Technique for Transcutaneous Measurement of Glomerular Filtration Rate With Ultralow Dose Marker Concentrations. IEEE Trans Biomed Eng 2015; 63:1742-50. [PMID: 26595905 DOI: 10.1109/tbme.2015.2501544] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECTIVE A novel high-precision approach [lifetime-decomposition measurement (LTDM)] for the assessment of the glomerular filtration rate (GFR) based on clearance measurements of exogenous filtration marker. METHODS The time-correlated single photon counting (TCSPC) acquisition in combination with a new decomposition method allows the separation of signal and background from transcutaneous measurements of GFR. RESULTS The performance of LTDM is compared versus the commercially available NIC-kidney patch-based system for transcutaneous GFR measurement. Measurements are performed in awake Sprague Dawley (SD) rats. Using the standard concentration required for the NIC-kidney system [7-mg/100-g body weight (b.w.) FITC-Sinistrin] as reference, the mean difference (bias) of the elimination curves GFR between LTDM and NIC-kidney was 4.8%. On the same animal and same day, the capability of LTDM to measure GFR with a FITC-Sinistrin dose reduced by a factor of 200 (35-μg/100-g b.w.) was tested as well. The mean differences (half lives with low dose using LTDM compared with those using first, the NIC-Kidney system and its standard concentration, and second, LTDM with the same concentration as for the NIC-Kidney system) were 3.4% and 4.5%, respectively. CONCLUSION We demonstrate that with the LTDM strategy substantial reductions in marker concentrations are possible at the same level of accuracy. SIGNIFICANCE LTDM aims to resolve the issue of the currently necessary large doses of fluorescence tracer required for transcutaneous GFR measurement. Due to substantially less influences from autofluorescence and artifacts, the proposed method outperforms other existing techniques for accurate percutaneous organ function measurement.
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Affiliation(s)
- Daniel N Meijles
- From the Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, PA
| | - Patrick J Pagano
- From the Department of Pharmacology and Chemical Biology, Vascular Medicine Institute, University of Pittsburgh, PA.
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Salehpour F, Ghanian Z, Yang C, Zheleznova NN, Kurth T, Dash RK, Cowley AW, Ranji M. Effects of p67phox on the mitochondrial oxidative state in the kidney of Dahl salt-sensitive rats: optical fluorescence 3-D cryoimaging. Am J Physiol Renal Physiol 2015; 309:F377-82. [PMID: 26062875 DOI: 10.1152/ajprenal.00098.2015] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 06/09/2015] [Indexed: 02/07/2023] Open
Abstract
The goal of the present study was to quantify and correlate the contribution of the cytosolic p67(phox) subunit of NADPH oxidase 2 to mitochondrial oxidative stress in the kidneys of the Dahl salt-sensitive (SS) hypertensive rat. Whole kidney redox states were uniquely assessed using a custom-designed optical fluorescence three-dimensional cryoimager to acquire multichannel signals of the intrinsic fluorophores NADH and FAD. SS rats were compared with SS rats in which the cytosolic subunit p67(phox) was rendered functionally inactive by zinc finger nuclease mutation of the gene (SS(p67phox)-null rats). Kidneys of SS rats fed a 0.4% NaCl diet exhibited significantly (P = 0.023) lower tissue redox ratio (NADH/FAD; 1.42 ± 0.06, n = 5) than SS(p67phox)-null rats (1.64 ± 0.07, n = 5), indicating reduced levels of mitochondrial electron transport chain metabolic activity and enhanced oxidative stress in SS rats. When fed a 4.0% salt diet for 21 days, both strains exhibited significantly lower tissue redox ratios (P < 0.001; SS rats: 1.03 ± 0.05, n = 9, vs. SS(p67phox)-null rats: 1.46 ± 0.04, n = 7) than when fed a 0.4% salt, but the ratio was still significantly higher in SS(p67phox) rats at the same salt level as SS rats. These results are consistent with results from previous studies that found elevated medullary interstitial fluid concentrations of superoxide and H2O2 in the medulla of SS rats. We conclude that the p67(phox) subunit of NADPH oxidase 2 plays an important role in the excess production of ROS from mitochondria in the renal medulla of the SS rat.
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Affiliation(s)
- F Salehpour
- Biophotonics Lab, University of Wisconsin, Milwaukee, Wisconsin; and
| | - Z Ghanian
- Biophotonics Lab, University of Wisconsin, Milwaukee, Wisconsin; and
| | - C Yang
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - N N Zheleznova
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - T Kurth
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - R K Dash
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - A W Cowley
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin
| | - M Ranji
- Biophotonics Lab, University of Wisconsin, Milwaukee, Wisconsin; and
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