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Rump LC, Stegbauer J. Coronary artery stenosis: a new risk factor for chronic kidney injury? Kidney Int 2015; 87:676-7. [PMID: 25826540 DOI: 10.1038/ki.2014.431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Coronary artery stenosis induces renal inflammation and kidney injury in pigs even in the absence of myocardial infarction or clinically significant heart failure. This effect is aggravated by experimentally induced renovascular hypertension. Interestingly, oxidative stress originating from the ischemic myocardium was identified as a possible mediator of this new pathophysiological link between heart and kidney. Renin-angiotensin or sympathetic nervous system activation did not appear to play a role in the observed cardio-renal link.
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Affiliation(s)
- Lars Christian Rump
- Department of Nephrology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
| | - Johannes Stegbauer
- Department of Nephrology, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
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Kumar R, Kohli S, Ali Z, Duhan K, Ram R, Gupta M, Tyagi S, Mohammad G, Pasha MQ. CYBA (p22phox) variants associate with blood pressure and oxidative stress markers in hypertension: a replication study in populations of diverse altitudes. Hypertens Res 2015; 38:498-506. [PMID: 25787042 DOI: 10.1038/hr.2015.31] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/27/2014] [Accepted: 12/11/2014] [Indexed: 02/07/2023]
Abstract
CYBA (p22(phox)) is an integral constituent of the NADPH oxidases and is consequently a main component of oxidative stress, which is strongly associated with hypertension. This study investigates the contribution of CYBA polymorphisms toward the complex etiology of hypertension in two ethnically different populations, one located at a high altitude and the other at a low altitude. The significance of CYBA single nucleotide polymorphisms and their correlation with clinical and biochemical phenotypes were investigated in age- and ethnicity-matched unrelated permanent high-altitude residents (>3500 m) comprising 245 controls and 241 patients. The results were replicated in a second population comprising 935 controls and 545 patients who lived at a low altitude (<200 m). The analysis of covariance revealed that CYBA risk alleles and their haplotypes, rs8854A/rs9932581G/rs4873C and rs8854G/rs9932581G/rs4873C, were positively correlated with clinical parameters, for example, systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP), and biochemical parameters, for example, 8-isoPGF2α level, and inversely correlated with catalase activity in patients compared with controls (P⩽0.01, each). Conversely, the protective alleles and their haplotype, rs8854G/rs9932581A/rs4873T, were inversely correlated with SBP, DBP, MAP and 8-isoPGF2α level, and positively correlated with catalase activity (P⩽0.001, each). Furthermore, correlation analysis between the clinical and biochemical parameters revealed a positive correlation of SBP, DBP and MAP with 8-isoPGF2α levels and a negative correlation with catalase activity in both populations (P<0.0001, each). CYBA (p22(phox)) variants influence the markers of oxidative stress and are associated with hypertension.
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Affiliation(s)
- Rahul Kumar
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Samantha Kohli
- 1] Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India [2] Academy of Scientific and Innovative Research, New Delhi, India
| | - Zahara Ali
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Kanika Duhan
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Rekhbala Ram
- Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India
| | - Mohit Gupta
- Department of Cardiology, G.B. Pant hospital, New Delhi, India
| | - Sanjay Tyagi
- Department of Cardiology, G.B. Pant hospital, New Delhi, India
| | | | - Ma Qadar Pasha
- 1] Functional Genomics Unit, CSIR-Institute of Genomics and Integrative Biology, Delhi, India [2] Academy of Scientific and Innovative Research, New Delhi, India
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Lerman LO, Textor SC. Gained in translation: protective paradigms for the poststenotic kidney. Hypertension 2015; 65:976-82. [PMID: 25712725 DOI: 10.1161/hypertensionaha.114.04364] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2014] [Accepted: 01/26/2015] [Indexed: 11/16/2022]
Affiliation(s)
- Lilach O Lerman
- From the Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN.
| | - Stephen C Textor
- From the Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN
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Alam MA, Chowdhury MRH, Jain P, Sagor MAT, Reza HM. DPP-4 inhibitor sitagliptin prevents inflammation and oxidative stress of heart and kidney in two kidney and one clip (2K1C) rats. Diabetol Metab Syndr 2015; 7:107. [PMID: 26609328 PMCID: PMC4658771 DOI: 10.1186/s13098-015-0095-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Accepted: 11/02/2015] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Hyperglycemia and insulin resistance often develop cardiovascular and nephrological dysfunction in diabetic patients. Sitagliptin is used to treat diabetes and showed potential benefit in lowering increased blood glucose level in diabetes. This investigation reports the effect of sitagliptin treatment on oxidative stress in kidney and heart of 2K1C rats. METHODS Male Long Evans rats underwent unilateral surgical stenosis of the renal artery [2-kidney-1-clip (2K1C) method]. These animals entered a 4-weeks dosing period with sitagliptin. Blood and urine sampling and organ harvesting were finally performed. Blood plasma, heart, kidney tissues and urine were tested for the assessment of inflammation and oxidative stress in kidney and heart of 2K1C rats after 4 weeks of surgery. RESULTS 2K1C rats showed cardiac hypertrophy, increased left ventricular wet weight compared to sham which was not significantly altered by sitagliptin treatment. Uric acid and creatinin concentrations were also increased in 2K1C rats. Sitagliptin significantly prevented the elevation of uric acid and creatinin concentration in plasma and urine in this rat model. Oxidative stress markers in plasma such as malondialdehyde (MDA), nitric oxide (NO), and advanced protein oxidation product (APOP) concentrations were increased in the 2K1C rats as compared to sham-operated animals. Increased concentrations of these oxidative stress markers were also normalized by sitagliptin treatment. 2K1C rats also showed increased level of uric acid and creatinine both in plasma and urine; which are also reduced to normal level in sitagliptin treated rats. Moreover, 2K1C surgery initiated inflammatory cell infiltration, increased MPO activity and fibrosis in both heart and kidneys which were further ameliorated by sitagliptin treatment. CONCLUSION Our study suggests that sitagliptin treatment in 2K1C rats prevented inflammation and fibrosis of heart and kidney by ameliorating elevated oxidative stress in heart and kidney tissues.
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Affiliation(s)
- Md. Ashraful Alam
- Department of Pharmaceutical Sciences, School of Life Sciences, North South University, Bashundhara, Dhaka, Bangladesh
| | - Mohammed Riaz Hasan Chowdhury
- Department of Pharmaceutical Sciences, School of Life Sciences, North South University, Bashundhara, Dhaka, Bangladesh
| | - Preeti Jain
- Department of Pharmaceutical Sciences, School of Life Sciences, North South University, Bashundhara, Dhaka, Bangladesh
| | - Md. Abu Taher Sagor
- Department of Pharmaceutical Sciences, School of Life Sciences, North South University, Bashundhara, Dhaka, Bangladesh
| | - Hasan Mahmud Reza
- Department of Pharmaceutical Sciences, School of Life Sciences, North South University, Bashundhara, Dhaka, Bangladesh
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55
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Abstract
Atherosclerotic renovascular disease is the most common cause of secondary hypertension. The patients with renovascular disease are at increased risk for adverse cardiac outcomes. Recent trials comparing medical therapy alone to medical therapy with stenting are flawed, but lay to rest any existing debate that unselected revascularization is unwarranted; however, revascularization may be appropriate in high-risk populations. Defining an appropriate population for revascularization is an area of ongoing study. Furthermore, delivery of optimal medical therapy in this population is inadequate. This review describes recent developments in renal artery revascularization.
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Affiliation(s)
- Sharon S Choi
- Division of Cardiology, Department of Internal Medicine, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA
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56
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Kasacka I, Piotrowska Ż, Knaś M, Lewandowska A. Quantitative and qualitative evaluation of CART-containing cells in adrenal glands of male rats with hypertension. Biotech Histochem 2014; 89:497-504. [PMID: 25151991 DOI: 10.3109/10520295.2014.902503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Adrenal activity is stimulated and secretion of stress hormones is increased during advanced stages of renovascular hypertension. The literature suggests that the neuropeptide, cocaine and amphetamine regulated transcript (CART), might regulate adrenal secretory function and thus could influence its activity. We assessed potential quantitative and qualitative changes in the cells that contained CART in the adrenal glands of rats with renovascular hypertension. The renal arteries of ten rats were subjected to a clipping procedure, i.e., two-kidney one-clip (2K1C) model of arterial hypertension, and after 6 weeks each rat developed stable hypertension. CART was localized using immunohistochemistry. CART was detected in a large population of cells in the medulla, sparse nerve fibers in the cortex and the capsule of the adrenal gland. The population of CART-positive cells in adrenal glands of two kidney-one clip (2K1C) treated rats was greater and their immunoreactivity was increased compared to controls. Similarly, the length, width, area and diameter of CART-immunoreactive cells were significantly greater in the hypertensive rats than in controls. We demonstrated that renovascular hypertension alters the number and immunoreactivity of CART-containing cells in adrenal glands.
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Affiliation(s)
- I Kasacka
- Department of Histology and Cytophysiology Medical University of Białystok ul . Mickiewicza 2C, 15-222 Białystok
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57
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Kasacka I, Piotrowska Z, Janiuk I, Zbucki R. Dynamics of cocaine- and amphetamine-regulated transcript containing cell changes in the adrenal glands of two kidney, one clip rats. Exp Biol Med (Maywood) 2014; 239:1292-9. [PMID: 24939825 DOI: 10.1177/1535370214538593] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Taking into consideration the homeostatic disorders resulting from renal hypertension and the essential role of cocaine- and amphetamine-regulated transcript (CART) in maintaining homeostasis by regulating many functions of the body, the question arises as to what extent the renovascular hypertension affects the morphology and dynamics of changes of CART-containing cells in the adrenal glands. The aim of the present study was to examine the distribution, morphology, and dynamics of changes of CART-containing cells in the adrenal glands of "two kidney, one clip" (2K1C) renovascular hypertension model in rats. The studies were carried out on the adrenal glands of rats after 3, 14, 28, 42, and 91 days from the renal artery clipping procedure. To identify neuroendocrine cells, immunohistochemical reaction was performed with the use of a specific antibody against CART. It was revealed that renovascular hypertension causes changes in the endocrine cells containing CART in the adrenal glands of rats. The changes observed in the endocrine cells depend on the time when the rats with experimentally induced hypertension were examined. In the first period of hypertension, the number and immunoreactivity of CART-containing cells were decreased, while from the 28-day test, it significantly increased, as compared to the control rats. CART is relevant to the regulation of homeostasis in the cardiovascular system and seems to be involved in renovascular hypertension. The results of the present work open the possibility of new therapeutic perspectives for the treatment of arterial hypertension, since CART function is involved in their pathophysiology.
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Affiliation(s)
- Irena Kasacka
- Department of Histology and Cytophysiology, Medical University, 15-222 Bialystok, Poland
| | - Zaneta Piotrowska
- Department of Histology and Cytophysiology, Medical University, 15-222 Bialystok, Poland
| | - Izabela Janiuk
- Department of Nutrition and Food Assessment, Institute of Health Sciences, University of Natural Sciences and Humanities, 08-110 Siedlce, Poland
| | - Robert Zbucki
- 1 Clinical Department of General and Endocrine Surgery, University Clinical Hospital, 15-264 Bialystok, Poland
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58
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Raaz U, Toh R, Maegdefessel L, Adam M, Nakagami F, Emrich FC, Spin JM, Tsao PS. Hemodynamic regulation of reactive oxygen species: implications for vascular diseases. Antioxid Redox Signal 2014; 20:914-28. [PMID: 23879326 PMCID: PMC3924901 DOI: 10.1089/ars.2013.5507] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
SIGNIFICANCE Arterial blood vessels functionally and structurally adapt to altering hemodynamic forces in order to accommodate changing needs and to provide stress homeostasis. This ability is achieved at the cellular level by converting mechanical stimulation into biochemical signals (i.e., mechanotransduction). Physiological mechanical stress helps maintain vascular structure and function, whereas pathologic or aberrant stress may impair cellular mechano-signaling, and initiate or augment cellular processes that drive disease. RECENT ADVANCES Reactive oxygen species (ROS) may represent an intriguing class of mechanically regulated second messengers. Chronically enhanced ROS generation may be induced by adverse mechanical stresses, and is associated with a multitude of vascular diseases. Although a causal relationship has clearly been demonstrated in large numbers of animal studies, an effective ROS-modulating therapy still remains to be established by clinical studies. CRITICAL ISSUES AND FUTURE DIRECTIONS This review article focuses on the role of various mechanical forces (in the form of laminar shear stress, oscillatory shear stress, or cyclic stretch) as modulators of ROS-driven signaling, and their subsequent effects on vascular biology and homeostasis, as well as on specific diseases such as arteriosclerosis, hypertension, and abdominal aortic aneurysms. Specifically, it highlights the significance of the various NADPH oxidase (NOX) isoforms as critical ROS generators in the vasculature. Directed targeting of defined components in the complex network of ROS (mechano-)signaling may represent a key for successful translation of experimental findings into clinical practice.
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Affiliation(s)
- Uwe Raaz
- 1 Division of Cardiovascular Medicine, Stanford University School of Medicine , Stanford, California
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59
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Boban M, Kocic G, Radenkovic S, Pavlovic R, Cvetkovic T, Deljanin-Ilic M, Ilic S, Bobana MD, Djindjic B, Stojanovic D, Sokolovic D, Jevtovic-Stoimenov T. Circulating purine compounds, uric acid, and xanthine oxidase/dehydrogenase relationship in essential hypertension and end stage renal disease. Ren Fail 2014; 36:613-8. [PMID: 24502620 DOI: 10.3109/0886022x.2014.882240] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Purine nucleotide liberation and their metabolic rate of interconversion may be important in the development of hypertension and its renal consequences. In the present study, blood triphosphate (ATP), adenosine diphosphate (ADP), and adenosine monophosphate (AMP) breakdown pathway was evaluated in relation to uric acid concentration and xanthine dehydrogenase/xanthine oxidase (XDH/XO) in patients with essential hypertension, patients with chronic renal diseases on dialysis, and control individuals. The pattern of nucleotide catabolism was significantly shifted toward catabolic compounds, including ADP, AMP, and uric acid in patients on dialysis program. A significant fall of ATP was more expressed in a group of patients on dialysis program, compared with the control value (p<0.001), while ADP and AMP were significantly increased in both groups of patients compared with control healthy individuals (p<0.001), together with their final degradation product, uric acid (p<0.001). The index of ATP/ADP and ATP/uric acid showed gradual significant fall in both the groups, compared with the control value (p<0.001), near five times in a group on dialysis. Total XOD was up-regulated significantly in a group with essential hypertension, more than in a group on dialysis. The activity of XO, which dominantly contributes reactive oxygen species (ROS) production, significantly increased in dialysis group, more than in a group with essential hypertension. In conclusion, the examination of the role of circulating purine nucleotides and uric acid in pathogenesis of hypertension and possible development of renal disease, together with XO role in ROS production, may help in modulating their liberation and ROS production in slowing progression from hypertension to renal failure.
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60
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Abstract
SIGNIFICANCE Renal oxidative stress can be a cause, a consequence, or more often a potentiating factor for hypertension. Increased reactive oxygen species (ROS) in the kidney have been reported in multiple models of hypertension and related to renal vasoconstriction and alterations of renal function. Nicotinamide adenine dinucleotide phosphate oxidase is the central source of ROS in the hypertensive kidney, but a defective antioxidant system also can contribute. RECENT ADVANCES Superoxide has been identified as the principal ROS implicated for vascular and tubular dysfunction, but hydrogen peroxide (H2O2) has been implicated in diminishing preglomerular vascular reactivity, and promoting medullary blood flow and pressure natriuresis in hypertensive animals. CRITICAL ISSUES AND FUTURE DIRECTIONS Increased renal ROS have been implicated in renal vasoconstriction, renin release, activation of renal afferent nerves, augmented contraction, and myogenic responses of afferent arterioles, enhanced tubuloglomerular feedback, dysfunction of glomerular cells, and proteinuria. Inhibition of ROS with antioxidants, superoxide dismutase mimetics, or blockers of the renin-angiotensin-aldosterone system or genetic deletion of one of the components of the signaling cascade often attenuates or delays the onset of hypertension and preserves the renal structure and function. Novel approaches are required to dampen the renal oxidative stress pathways to reduced O2(-•) rather than H2O2 selectivity and/or to enhance the endogenous antioxidant pathways to susceptible subjects to prevent the development and renal-damaging effects of hypertension.
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Affiliation(s)
- Magali Araujo
- Hypertension, Kidney and Vascular Research Center, Georgetown University , Washington, District of Columbia
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61
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Zhou R, Stouffer GA. Is Time of Renal Hypoperfusion an Important Variable in Determining Response to Renal Artery Revascularization? JACC Cardiovasc Interv 2014; 7:110. [DOI: 10.1016/j.jcin.2013.12.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/02/2013] [Accepted: 12/02/2013] [Indexed: 10/25/2022]
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62
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Eirin A, Lerman LO. Darkness at the end of the tunnel: poststenotic kidney injury. Physiology (Bethesda) 2013; 28:245-53. [PMID: 23817799 DOI: 10.1152/physiol.00010.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Renal artery stenosis remains an important contributor to renal failure in the elderly population, but uncertainty continues to surround the mechanisms underlying progressive renal dysfunction. Here, we present the current understanding of the pathogenic mechanisms responsible for renal injury in these patients, with emphasis on those involved in disease progression.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
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63
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Redox signaling is an early event in the pathogenesis of renovascular hypertension. Int J Mol Sci 2013; 14:18640-56. [PMID: 24025423 PMCID: PMC3794800 DOI: 10.3390/ijms140918640] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2013] [Revised: 08/30/2013] [Accepted: 09/02/2013] [Indexed: 01/11/2023] Open
Abstract
Activation of the renin-angiotensin-aldosterone system plays a critical role in the development of chronic renal damage in patients with renovascular hypertension. Although angiotensin II (Ang II) promotes oxidative stress, inflammation, and fibrosis, it is not known how these pathways intersect to produce chronic renal damage. We tested the hypothesis that renal parenchymal cells are subjected to oxidant stress early in the development of RVH and produce signals that promote influx of inflammatory cells, which may then propagate chronic renal injury. We established a reproducible murine model of RVH by placing a tetrafluoroethylene cuff on the right renal artery. Three days after cuff placement, renal tissue demonstrates no histologic abnormalities despite up regulation of both pro- and anti-oxidant genes. Mild renal atrophy was observed after seven days and was associated with induction of Tnfα and influx of CD3⁺ T cells and F4/80⁺ macrophages. By 28 days, kidneys developed severe renal atrophy with interstitial inflammation and fibrosis, despite normalization of plasma renin activity. Based on these considerations, we propose that renal parenchymal cells initiate a progressive cascade of events leading to oxidative stress, interstitial inflammation, renal fibrosis, and atrophy.
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64
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DING YU, XIA BOHOU, YU JINFANG, LENG JIANHANG, HUANG JINYU. Mitochondrial DNA mutations and essential hypertension (Review). Int J Mol Med 2013; 32:768-74. [DOI: 10.3892/ijmm.2013.1459] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2013] [Accepted: 07/22/2013] [Indexed: 11/06/2022] Open
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65
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Campagnaro BP, Tonini CL, Doche LM, Nogueira BV, Vasquez EC, Meyrelles SS. Renovascular hypertension leads to DNA damage and apoptosis in bone marrow cells. DNA Cell Biol 2013; 32:458-66. [PMID: 23786322 DOI: 10.1089/dna.2013.2065] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Angiotensin II (Ang II), which plays a pivotal role in the pathophysiology of the two-kidney, one-clip (2K1C) Goldblatt hypertension, has been associated with augmented generation of reactive oxygen species (ROS) in some cells and tissues. In the present study, we evaluated the influence of 2K1C hypertension on oxidative stress, DNA fragmentation, and apoptosis of bone marrow (BM) cells. Two weeks after the renal artery clipping or Sham operation, flow cytometry analysis showed a higher production of superoxide anions (approximately sixfold) and hydrogen peroxide (approximately twofold) in 2K1C hypertensive than in Sham normotensive mice. 2K1C mice also showed an augmented DNA fragmentation (54%) and apoptotic cells (21%). Our data show that the 2K1C renovascular hypertension is characterized by an increased production of ROS, DNA damage, and apoptosis of BM, which is a fundamental source of the cells involved in tissue repair.
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Affiliation(s)
- Bianca P Campagnaro
- Laboratory of Transgenes, Health Sciences Center, Federal University of Espirito Santo, Vitoria, ES, Brazil
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66
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Fedorova LV, Sodhi K, Gatto-Weis C, Puri N, Hinds TD, Shapiro JI, Malhotra D. Peroxisome proliferator-activated receptor δ agonist, HPP593, prevents renal necrosis under chronic ischemia. PLoS One 2013; 8:e64436. [PMID: 23691217 PMCID: PMC3654981 DOI: 10.1371/journal.pone.0064436] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2012] [Accepted: 04/15/2013] [Indexed: 12/15/2022] Open
Abstract
The Goldblatt’s 2 kidney 1 clip (2K1C) rat animal model of renovascular hypertension is characterized by ischemic nephropathy of the clipped kidney. 2K1C rats were treated with a specific peroxisome proliferator-activated receptor δ (PPARδ) agonist, HPP593. Clipped kidneys from untreated rats developed tubular and glomerular necrosis and massive interstitial, periglomerular and perivascular fibrosis. HPP593 kidneys did not exhibit any histochemical features of necrosis; fibrotic lesions were present only in perivascular areas. Necrosis in the untreated clipped kidneys was associated with an increased oxidative stress, up regulation and mitochondrial translocation of the pro-death protein BNIP3 specifically in tubules. In the kidneys of HPP593-treated rats oxidative stress was attenuated and BNIP3 protein decreased notably in the mitochondrial fraction when compared to untreated animals. In untreated clipped kidneys, mitochondria were dysfunctional as revealed by perturbations in the levels of MCAD, COXIV, TFAM, and Parkin proteins and AMPK activation, while in HPP593-treated rats these proteins remained at the physiological levels. Nuclear amounts of oxidative stress-responsive proteins, NRF1 and NRF2 were below physiological levels in treated kidneys. Mitochondrial biogenesis and autophagy were inhibited similarly in both treated and untreated 2K1C kidneys as indicated by a decrease in PGC1-α and deficiency of the autophagy-essential proteins LC3-II and ATG5. However, HPP593 treatment resulted in increased accumulation of p62 protein, an autophagic substrate and an enhancer of NRF2 activity. Therefore, inhibition of BNIP3 activation by the preservation of mitochondrial function and control of oxidative stress by PPARδ is the most likely mechanism to account for the prevention of necrotic death in the kidney under conditions of persistent ischemia.
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Affiliation(s)
- Larisa V Fedorova
- Department of Medicine, The University of Toledo School of Medicine, Toledo, Ohio, United States of America.
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67
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Balafa O, Kalaitzidis R, Siamopoulos KC. Optimal medical management in patients with renovascular hypertension. Am J Cardiovasc Drugs 2013; 13:71-8. [PMID: 23494905 DOI: 10.1007/s40256-013-0011-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Renovascular hypertension refers to the rise of arterial pressure due to reduced perfusion of the kidney caused by the stenotic renal artery/ies. The most common cause of stenotic renal artery is atherosclerosis. Atherosclerotic renal stenosis is usually part of a systemic syndrome that involves hypertension, intrinsic renal damage, and cardiovascular morbidity. So far, large trials have not proven the superiority of interventional therapies to medical management. As a result, renal artery stenosis should be treated mainly as a coronary artery disease equivalent focusing on rigorous management of hypertension, hyperglycemia, and hyperlipidemia. Antihypertensive treatment should include renin-angiotensin system blockade medication in most cases, while HMG-CoA reductase inhibitors (statins) can be used even in chronic kidney disease with safety. Lifestyle modifications, such as cessation of smoking, and antiplatelet therapy have reduced the risk of cardiovascular events in high-risk patients.
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Affiliation(s)
- Olga Balafa
- Department of Nephrology, University Hospital of Ioannina, and Department of Internal Medicine, Medical School, University of Ioannina, Ioannina, Greece.
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68
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Campese VM, Ye S. A vitamin-E-fortified diet reduces oxidative stress, sympathetic nerve activity, and hypertension in the phenol-renal injury model in rats. ACTA ACUST UNITED AC 2012; 1:242-50. [PMID: 20409856 DOI: 10.1016/j.jash.2007.04.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2007] [Revised: 04/19/2007] [Accepted: 04/20/2007] [Indexed: 02/07/2023]
Abstract
Renal injury caused by the injection of phenol in the lower pole of one kidney increases sympathetic nervous system (SNS) activity and blood pressure (BP), and these effects are mediated by increased reactive oxygen species (ROS) in brain nuclei involved in the noradrenergic control of BP. This suggests that therapy with antioxidants might be beneficial in this model. In this study, we tested the hypothesis that a vitamin (Vit)-E-enriched diet might decrease oxidative stress in the brain and result in reduced SNS activity and BP in animals with phenol-renal injury. To this end, we examined the effects of a Vit-E-fortified diet vs. a control diet on BP, norepinephrine (NE) secretion from the posterior hypothalamic nuclei (PH), and the abundance of several components of Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidase in the brain of rats with phenol-induced renal injury. A Vit-E-fortified diet mitigated the formation of ROS in the brain, and this was associated with reduced SNS activity and BP in rats with phenol-induced renal injury. In conclusion, antioxidants appear to be beneficial in the management of hypertension caused by renal injury and increased SNS activity.
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Affiliation(s)
- Vito M Campese
- Division of Nephrology; and the Hypertension Center, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
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69
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Heslop CL, Tebbutt SJ, Podder M, Ruan J, Hill JS. Combined Polymorphisms in Oxidative Stress Genes Predict Coronary Artery Disease and Oxidative Stress in Coronary Angiography Patients. Ann Hum Genet 2012; 76:435-47. [DOI: 10.1111/j.1469-1809.2012.00731.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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Sánchez-Benito JL, Pontes Torrado Y, González Rodríguez A. La intervención de pérdida de peso conlleva una disminución significativa de la presión arterial y del colesterol. CLÍNICA E INVESTIGACIÓN EN ARTERIOSCLEROSIS 2012. [DOI: 10.1016/j.arteri.2012.04.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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71
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Barp J, Sartório CL, Campos C, Llesuy SF, Araujo AS, Belló-Klein A. Influence of ovariectomy on cardiac oxidative stress in a renovascular hypertension model. Can J Physiol Pharmacol 2012; 90:1229-34. [PMID: 22900708 DOI: 10.1139/y2012-078] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The aim of this study was to evaluate the potential influence of endogenous ovarian hormones on cardiac oxidative stress in renovascular hypertension. Female Wistar rats (N = 10 per group) were divided among 4 groups: (i) normotensive control; (ii) hypertensive control; (iii) normotensive ovariectomized; and (iv) hypertensive ovariectomized rats. To induce hypertension, 2-kidney 1-clip (2K1C) Goldblatt's method was followed. Blood pressure (BP) was enhanced (25%) in 2K1C and it was not further altered in hypertensive ovariectomized animals. Lipid peroxidation (measured by thiobarbituric acid reactive substances; TBARS) increased in heart homogenates after ovariectomy (253%) and was additionally augmented when associated with hypertension (by 28%). Superoxide dismutase and catalase activities were similar in both hypertensive groups. Hypertension enhanced glutathione peroxidase activity (75%), but the association with ovariectomy prevented this change. Total radical trapping antioxidant potential (TRAP) decreased in hypertensive rats (34%) and was recovered when associated with ovariectomy. However, this adaptation seems not to be sufficient to avoid the increased oxidative damage in ovariectomized hypertensive animals. These results suggest a protective role for physiological ovarian hormones in the cardiac oxidative stress induced by 2K1C hypertension.
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Affiliation(s)
- Jaqueline Barp
- Cardiovascular Physiology Laboratory, Federal University of Rio Grande do Sul, CEP, Porto Alegre, Brazil
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72
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Cervantes-Pérez LG, Ibarra-Lara MDLL, Escalante B, Del Valle-Mondragón L, Vargas-Robles H, Pérez-Severiano F, Pastelín G, Sánchez-Mendoza MA. Endothelial nitric oxide synthase impairment is restored by clofibrate treatment in an animal model of hypertension. Eur J Pharmacol 2012; 685:108-15. [PMID: 22542661 DOI: 10.1016/j.ejphar.2012.04.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 04/02/2012] [Accepted: 04/05/2012] [Indexed: 12/29/2022]
Abstract
Adequate production of nitric oxide (NO) by endothelial nitric oxide synthase (eNOS) requires eNOS coupling promoted by tetrahydrobiopterin (BH(4)). Under pathological conditions such as hypertension, BH(4) is diminished, avoiding eNOS coupling. When eNOS is "uncoupled", it yields a superoxide anion instead of NO. Peroxisome proliferator activated receptors (NR1C) are a family of nuclear receptors activated by ligand. Clofibrate, a member of a hypolipidemic class of drugs, acts by activating the alpha isoform of NR1C. To determine the participation of NR1C1 activation in BH(4) and dihydrobiopterin (BH(2)) metabolism and its implications on eNOS coupling in hypertension, we performed aortic coarctation (AoCo) at inter-renal level on male Wistar rats in order to have a hypertensive model. Rats were divided into the following groups: Sham+vehicle (Sham-V); AoCo+vehicle (AoCo-V); Sham+clofibrate (Sham-C), and AoCo+clofibrate (AoCo-C). Clofibrate (7 days) increased eNOS coupling in the AoCo-C group compared with AoCo-V. Clofibrate also recovered the BH(4):BH(2) ratio in control values and prevented the rise in superoxide anion production, lipoperoxidation, and reactive oxygen species production. In addition, clofibrate increased GTP cyclohydrolase-1 (GTPCH-1) protein expression, which is related with BH(4) recovered production. NR1C1 stimulation re-establishes eNOS coupling, apparently through recovering the BH(4):BH(2) equilibrium and diminishing oxidative stress. Both can contribute to high blood pressure attenuation in hypertension secondary to AoCo.
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Affiliation(s)
- Luz Graciela Cervantes-Pérez
- Department of Pharmacology, Instituto Nacional de Cardiología Ignacio Chávez, Juan Badiano No. 1, Col. Sección XVI, Tlalpan, 14080 México, DF, Mexico
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73
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Northcott CA, Billecke S, Craig T, Hinojosa-Laborde C, Patel KP, Chen AF, D'Alecy LG, Haywood JR. Nitric oxide synthase, ADMA, SDMA, and nitric oxide activity in the paraventricular nucleus throughout the etiology of renal wrap hypertension. Am J Physiol Heart Circ Physiol 2012; 302:H2276-84. [PMID: 22447945 DOI: 10.1152/ajpheart.00562.2011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Within the paraventricular nucleus (PVN), there is a balance between the excitatory and inhibitory neurotransmitters that regulate blood pressure; in hypertension, the balance shifts to enhanced excitation. Nitric oxide (NO) is an atypical neurotransmitter that elicits inhibitory effects on cardiovascular function. We hypothesized that reduced PVN NO led to elevations in blood pressure during both the onset and sustained phases of hypertension due to decreased NO synthase (NOS) and increased asymmetrical dimethylarginine (ADMA; an endogenous NOS inhibitor) and symmetric dimethylarginine (SDMA). Elevated blood pressure, in response to PVN bilateral microinjections of a NO inhibitor, nitro-L-arginine methyl ester, was blunted in renal wrapped rats during the onset of hypertension (day 7) and sustained renal wrap hypertension (day 28) compared with sham-operated rats. Adenoviruses (Ad) encoding endothelial NOS (eNOS) or LacZ microinjected into the PVN [1 × 10(9) plaque-forming units, bilateral (200 nl/site)] reduced mean arterial pressure compared with control (Day 7, Ad LacZ wrap: 144 ± 7 mmHg and Ad eNOS wrap: 117 ± 5 mmHg, P ≤ 0.05) throughout the study (Day 28, Ad LacZ wrap: 123 ± 1 mmHg and Ad eNOS wrap: 108 ± 4 mmHg, P ≤ 0.05). Western blot analyses of PVN NOS revealed significantly lower PVN neuronal NOS during the onset of hypertension but not in sustained hypertension. Reduced SDMA was found in the PVN during the onset of hypertension; however, no change in ADMA was observed. In conclusion, functional indexes of NO activity indicated an overall downregulation of NO in renal wrap hypertension, but the mechanism by which this occurs likely differs throughout the development of hypertension.
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Affiliation(s)
- Carrie A Northcott
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, 48824, USA
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74
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Tian XY, Wong WT, Leung FP, Zhang Y, Wang YX, Lee HK, Ng CF, Chen ZY, Yao X, Au CL, Lau CW, Vanhoutte PM, Cooke JP, Huang Y. Oxidative stress-dependent cyclooxygenase-2-derived prostaglandin f(2α) impairs endothelial function in renovascular hypertensive rats. Antioxid Redox Signal 2012; 16:363-73. [PMID: 21951274 PMCID: PMC3584508 DOI: 10.1089/ars.2010.3874] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
UNLABELLED Abstract Aims: The role of endothelium-derived contracting factors (EDCFs) in regulating renovascular function is yet to be elucidated in renovascular hypertension (RH). The current study investigated whether oxidative stress-dependent cyclooxygenase (COX)-2-derived prostaglandin F(2α) (PGF(2α)) impairs endothelial function in renal arteries of renovascular hypertensive rats (RHR). RESULTS Renal hypertension was induced in rats by renal artery stenosis of both kidneys using the 2-kidney 2-clip model. Acute treatment with reactive oxygen species (ROS) scavengers, COX-2 inhibitors, and thromboxane-prostanoid receptor antagonists, but not COX-1 inhibitors, improved endothelium-dependent relaxations and eliminated endothelium-dependent contractions in RHR renal arteries. Five weeks of treatment with celecoxib or tempol reduced blood pressure, increased renal blood flow, and restored endothelial function in RHRs. Increased ROS production in RHR arteries was inhibited by ROS scavengers, but unaffected by COX-2 inhibitors; whereas increased PGF(2α) release was reduced by both ROS scavengers and COX-2 inhibitors. ROS also induced COX-2-dependent contraction in RHR renal arteries, which was accompanied by the release of COX-2-derived PGF(2α). Further, chronic tempol treatment reduced COX-2 and BMP4 upregulation, p38MAPK phosphorylation, and the nitrotyrosine level in RHR renal arteries. CONCLUSION These findings demonstrate the functional importance of oxidative stress, which serves as an initiator of increased COX-2 activity, and that COX-2-derived PGF(2α) plays an important role in mediating endothelial dysfunction in RH. INNOVATION The current study, thus, suggests that drugs targeting oxidative stress-dependent COX-2-derived PGF(2α) may be useful in the prevention and management of RH. Antioxid. Redox Signal. 16, 363-373.
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Affiliation(s)
- Xiao Yu Tian
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong SAR, China
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Wu XQ, Kong X, Zhou Y, Huang K, Yang JR, Li XL. Sesamin exerts renoprotective effects by enhancing NO bioactivity in renovascular hypertensive rats fed with high-fat-sucrose diet. Eur J Pharmacol 2012; 683:231-7. [PMID: 22314221 DOI: 10.1016/j.ejphar.2012.01.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2011] [Revised: 01/18/2012] [Accepted: 01/21/2012] [Indexed: 11/15/2022]
Abstract
In the present study, we aimed to evaluate the protective effect of sesamin on kidney damage and renal endothelial dysfunction in two-kidney, one-clip renovascular hypertensive rats fed with a high-fat-sucrose diet (2K1C rats on HFS diet). Sesamin was intragastrically administered to 2K1C rats on HFS diet for eight weeks. Then, we measured the levels of serum hydrogen peroxide (H₂O₂), total antioxidant capability (T-AOC), renal malonaldehyde (MDA), total-erythrocuprein (T-SOD) and glutathione peroxidase (GSH-P(X)). The expressions of endothelial nitric oxide synthase (eNOS), nitrotyrosine and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunit p47(phox) in the left and right renal cortexes were detected by Western blotting. Pathological changes in the left and right renal cortexes were observed by periodic acid-schiff staining (PAS) and Masson's staining. Treatment with sesamin (120 and 60mg/kg⁻¹·d⁻¹) in 2K1C rats on HFS diet improved renal function, corrected structural abnormalities, and attenuated renal oxidative stress. Furthermore, sesamin increased eNOS protein expression and reduced nitrotyrosine and p47phox protein expression. These results demonstrated that long-term treatment with sesamin had renoprotective effect and improved renal endothelial dysfunction via upregulation of eNOS expression and reduction of NO oxidative inactivation in both clipped and contralateral kidneys of 2K1C rats on HFS diet, and sesamin may have a favorably therapeutic value in treating chronic kidney disease in patients with hypertension and hyperlipemia.
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Affiliation(s)
- Xiang-Qi Wu
- Department of Cardiology, the First Affiliated Hospital of Nanjing Medical University, Nanjing, China
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76
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Enhanced endothelial progenitor cell angiogenic potency, present in early experimental renovascular hypertension, deteriorates with disease duration. J Hypertens 2012; 29:1972-9. [PMID: 21873884 DOI: 10.1097/hjh.0b013e32834ae611] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Endothelial progenitor cells (EPCs) augment neovascularization and repair of damaged tissues, but may undergo functional changes during exposure to cardiovascular risk factors. This study tested the hypothesis that early renovascular hypertension (RVH) modulates the temporal pattern of EPC function that deteriorates with disease duration. METHODS RVH was induced in domestic pigs by unilateral renal artery stenosis. EPCs were cultured after 3, 6, and 12 weeks of RVH or normal control to evaluate EPC function, growth factor, and homing receptor expression. Plasma renin activity (PRA), vascular endothelial growth factor (VEGF), and its soluble receptor-1 (sFlt-1) were measured in plasma. EPCs (10 × 10) isolated from 3-week RVH or from normal pigs were also injected into control kidneys (n = 6-7, each group), and 4 weeks later single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were evaluated. Microvascular density was studied ex vivo using microcomputed tomography. RESULTS Blood pressure peaked at 3 weeks and remained higher than normal throughout the study. Systemic PRA also peaked after 3 weeks of RVH and declined thereafter, whereas sFlt-1 showed a reciprocal pattern. In vivo, only RVH but not normal EPCs increased RBF, GFR, and microvascular density. RVH-EPCs showed in vitro enhanced proliferation, tube formation, VEGF, and homing receptor expression that peaked at 3 weeks, which were abolished by valsartan and returned to baseline levels after 12 weeks of RVH. EPC number remained unchanged throughout the study. CONCLUSION A transient enhancement of EPC function, mediated by angiotensin II, may contribute to compensatory vascular adaptation in early RVH, but is lost as hypertension persists.
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77
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Secondary arterial hypertension: improvements in diagnosis and management in the last 10 years. Am J Ther 2012; 18:403-15. [PMID: 21869672 DOI: 10.1097/mjt.0b013e3181c0805a] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The diagnosis and management of secondary hypertension has improved in the last decade as a result of the advances in the acknowledgment of some physiopathologic mechanisms and mainly by the development of new diagnostic methods. Furthermore, the treatment of some types of secondary hypertension may be solved by noninvasive techniques. Hypertension of renal and renovascular origin, coarctation of the aorta, primary hyperaldosteronism, and adrenal medullary tumors are analyzed. The main results of some relevant studies on diagnostic and treatment of those diseases are presented. Also, some experimental methods are mentioned, taking into account the possibility of clinical use in the near future.
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Textor SC, Gloviczki ML, Flessner MF, Calhoun DA, Glockner J, Grande JP, McKusick MA, Cha SS, Lerman LO. Association of filtered sodium load with medullary volumes and medullary hypoxia in hypertensive African Americans as compared with whites. Am J Kidney Dis 2011; 59:229-37. [PMID: 22130642 DOI: 10.1053/j.ajkd.2011.09.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2011] [Accepted: 09/28/2011] [Indexed: 11/11/2022]
Abstract
BACKGROUND African Americans develop hypertension earlier with more target manifestations than whites despite having a higher glomerular filtration rate (GFR) for any level of serum creatinine. STUDY DESIGN & PARTICIPANTS: This study tested the hypothesis that increased GFR and sodium reabsorption in African Americans is associated with increased metabolic work and medullary hypoxia in 49 nondiabetic patients with essential hypertension (29 whites and 20 African Americans) following a constant-sodium diet (150 mEq/d) and renin-angiotensin system blockade. PREDICTORS Ethnicity, age, measured GFR, sodium excretion, and body mass index. OUTCOMES We examined cortical and medullary volumes and blood flows using multidetector computed tomography and intrarenal deoxyhemoglobin (R2*) using blood oxygen level-dependent magnetic resonance. RESULTS Blood pressure and sodium excretion were similar, whereas African Americans were more obese and had higher iothalamate GFRs. Renal cortical volumes did not differ, but medullary volumes adjusted for body size and age were higher in African Americans (32.3 ± 11.2 vs 25.1 ± 7.4 cm(3)/m(2) body surface area; P < 0.001). Sodium reabsorption and blood flows were higher in African Americans. Basal cortical deoxyhemoglobin values were similar between ethnic groups, whereas medullary R2* was higher in African Americans (39.7 ± 5.1 vs 36.3 ± 6.5/s; P = 0.02), but decreased to levels similar to whites after furosemide treatment. Levels of the circulating isoprostane prostaglandin F(2α) were higher in African Americans and daily urinary prostaglandin F(2α) excretion in African Americans correlated directly with renal blood flow (R = 0.71; P < 0.01). LIMITATIONS Studies were limited to treated volunteers with normal kidney function without knowledge of prior nutrient intake. CONCLUSIONS These data show for the first time that increased sodium reabsorption in obese African American patients with hypertension was associated with enlarged medullary volumes, functional hypoxia related to solute reabsorption, and a direct relationship between blood flows and urinary isoprostane levels. Our results support a model of increased oxygen consumption and oxidative stress in African Americans that may accelerate hypertension and target-organ injury compared with white patients with essential hypertension.
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79
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Urbieta-Caceres VH, Zhu XY, Jordan KL, Tang H, Textor K, Lerman A, Lerman LO. Selective improvement in renal function preserved remote myocardial microvascular integrity and architecture in experimental renovascular disease. Atherosclerosis 2011; 221:350-8. [PMID: 22341593 DOI: 10.1016/j.atherosclerosis.2011.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/20/2011] [Accepted: 10/01/2011] [Indexed: 11/19/2022]
Abstract
AIM Atherosclerotic renovascular disease (ARVD) may impair renal function and increase cardiovascular morbidity and mortality, but the mechanism by which ARVD impacts cardiovascular function is unclear. We tested the hypothesis that preservation of renal function can reverse cardiac dysfunction in ARVD. METHODS AND RESULTS Endothelial progenitor cells (EPC) were injected intra-renally (ARVD+EPC) after 6 weeks of swine ARVD (concurrent hypercholesterolemia and renovascular hypertension), and single-kidney function and myocardial blood-flow and microvascular permeability (MP) responses to adenosine were assessed using CT 4 weeks later. Myocardial microvascular density was evaluated by micro-CT. Inflammation and oxidative-stress were assessed in kidney venous and systemic blood samples. Normal and untreated ARVD pigs served as controls. Blood pressure was similarly increased in ARVD and ARVD+EPC. Compared to normal, ARVD showed lower glomerular filtration rate, elevated renal vein and systemic oxidized LDL (ox-LDL), aldosterone, uric acid, isoprostanes, transforming growth factor (TGF)-β, and interleukine-6. Renal vein ox-LDL and TGF-β showed a positive gradient across the stenotic kidney, indicating increased renal oxidative stress and fibrogenic activity. Furthermore, ARVD impaired myocardial blood-flow and MP response to adenosine, decreased microvascular density, and induced myocardial fibrosis. Improvement of renal function in ARVD+EPC decreased systemic aldosterone, inflammation, and oxidative stress, and improved myocardial microvascular integrity and density. CONCLUSION Selective improvement in renal function, which reduced renal and systemic oxidative stress and inflammation, preserved remote myocardial microvascular function and architecture, despite enduring hypertension. These findings underscore functionally important cardiorenal crosstalk possibly mediated by renal injury signals.
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Campos RR, Oliveira-Sales EB, Nishi EE, Boim MA, Dolnikoff MS, Bergamaschi CT. The role of oxidative stress in renovascular hypertension. Clin Exp Pharmacol Physiol 2011; 38:144-52. [PMID: 20678153 DOI: 10.1111/j.1440-1681.2010.05437.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
1. There is mounting evidence that increased oxidative stress and sympathetic nerve activity play important roles in renovascular hypertension. In the present review, we focus on the importance of oxidative stress in two distinct populations of neurons involved with cardiovascular regulation: those of the rostral ventrolateral medulla (RVLM) and those of the paraventricular nucleus of the hypothalamus (PVN) in the maintenance of sympathoexcitation and hypertension in two kidney-one clip (2K1C) hypertensive rats. Furthermore, the role of oxidative stress in the clipped kidney is also discussed. 2. In the studies reviewed in this article, it was found that hypertension and renal sympathoexcitation in 2K1C rats were associated with an increase in Angiotensin II type one receptor (AT(1) ) expression and in oxidative markers within the RVLM, PVN and in the clipped kidneys of 2K1C rats. Furthermore, acute or chronic anti-oxidant treatment decreased blood pressure and sympathetic activity, and improved the baroreflex control of heart rate and renal sympathetic nerve activity in 2K1C rats. Tempol or vitamin C administration in the RVLM, PVN or systemically all reduced blood pressure and renal sympathetic activity. Cardiovascular improvement in response to chronic anti-oxidant treatment was associated with a downregulation of AT(1) receptors, as well as oxidative markers in the central nuclei and clipped kidney. 3. The data discussed in the present review support the idea that an increase in oxidative stress within the RVLM, PVN and in the ischaemic kidney plays a major role in the maintenance of sympathoexcitation and hypertension in 2K1C rats.
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Affiliation(s)
- Ruy R Campos
- Department of Physiology, Cardiovascular Division Department of Medicine, Nephrology Division, Federal University of São Paulo, São Paulo, Brazil.
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81
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Baumgartner I, Lerman LO. Renovascular hypertension: screening and modern management. Eur Heart J 2011; 32:1590-8. [PMID: 21273200 PMCID: PMC3128298 DOI: 10.1093/eurheartj/ehq510] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 11/09/2010] [Accepted: 12/16/2010] [Indexed: 02/02/2023] Open
Abstract
The diagnosis and management of patients with renovascular disease and hypertension continue to elude healthcare providers. The advent of novel imaging and interventional techniques, and increased understanding of the pathways leading to irreversible renal injury and renovascular hypertension, have ushered in commendable attempts to optimize and fine-tune strategies to preserve or restore renal function and control blood pressure. Large randomized clinical trials that compare different forms of therapy, and smaller trials that test novel experimental treatments, will hopefully help formulate innovative concepts and tools to manage the patient population with atherosclerotic renovascular disease.
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Affiliation(s)
- Iris Baumgartner
- Department of Clinical and Interventional Angiology, Swiss Cardiovascular Center, University of Bern, Switzerland
| | - Lilach O. Lerman
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Abstract
Renal artery stenosis (RAS) is characterized by a heterogeneous group of pathophysiologic entities, of which fibromuscular dysplasia and atherosclerotic RAS (ARAS) are the most common. Whether and which patients should undergo revascularization for ARAS is controversial. The general consensus is that all patients with ARAS should receive intensive medical treatment. The latest randomized clinical trials have increased confusion regarding recommendations for revascularization for ARAS. Although revascularization is not indicated in all patients with ARAS, experts agree that it should be considered in some patients, especially those with unstable angina, unexplained pulmonary edema, and hemodynamically significant ARAS with either worsening renal function or with difficult to control hypertension. A search of the literature was performed using PubMed and entering the search terms renal artery stenosis, atherosclerotic renal artery stenosis, and renal artery stenosis AND hypertension to retrieve the most recent publications on diagnosis and treatment of ARAS. In this review, we analyze the pathways related to hypertension in ARAS, the optimal invasive and noninvasive modalities for evaluating the renal arteries, and the available therapies for ARAS and assess future tools and algorithms that may prove useful in evaluating patients for renal revascularization therapy.
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Affiliation(s)
- David Lao
- Division of Cardiology, University of California San Francisco, San Francisco, CA 94143-0103, USA
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Mansour SM, Bahgat AK, El-Khatib AS, Khayyal MT. Ginkgo biloba extract (EGb 761) normalizes hypertension in 2K, 1C hypertensive rats: role of antioxidant mechanisms, ACE inhibiting activity and improvement of endothelial dysfunction. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2011; 18:641-647. [PMID: 21353510 DOI: 10.1016/j.phymed.2011.01.014] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2010] [Revised: 11/15/2010] [Accepted: 01/15/2011] [Indexed: 05/30/2023]
Abstract
The 2 kidney, 1-clip (2K, 1C) model of hypertension was used to investigate the potential antihypertensive effect of a standardized leaf extract of Ginkgo biloba (EGb 761). Clipping of the renal artery resulted in gradual elevation of the systolic blood pressure (SBP) reaching a plateau after 4 weeks of surgery. Treatment of hypertensive rats with EGb 761 (60, 90, 180 mg/kg/day orally) was therefore started 4 weeks after surgery and continued for 3 weeks. This led to a dose-dependent reduction in SBP with no significant change in heart rate. Control hypertensive rats showed a significant elevation of total protein thiols (Pr-SHs level) in both clipped and non-clipped kidneys as well as in the serum. However, glutathione peroxidase (GSH-Px) activity was decreased in the clipped kidneys but elevated in the non-clipped ones and in the blood. The malondialdehyde (MDA) level was raised in clipped kidneys but not in non-clipped ones nor in the serum. Nitric oxide (NO level) and angiotensin converting enzyme (ACE) activity were increased in both clipped and non-clipped kidneys but not in the serum. Endothelium-dependent and -independent relaxation of aortic rings towards acetylcholine (Ach) and sodium nitroprusside (SNP) were impaired. Treatment with EGb 761 (180 mg/kg/day for 3 weeks) was associated with recovery of GSH-Px activity in clipped kidneys, inhibition of ACE activity in both kidneys and a reduction in the elevated NO level of the non-clipped kidneys, decreased responsiveness to the vasoconstrictor NE and improvement of endothelial function as evidenced by restoration of endothelium-dependent vasorelaxation induced by Ach. The observed beneficial effects of the EGb 761 may be attributed to different factors, including ACE inhibition and maintenance of cellular antioxidant capacity as well as preserving vascular reactivity towards endothelium-dependent and -independent vasodilators while inhibiting responses to vasoconstrictors.
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Affiliation(s)
- Suzan M Mansour
- Department of Pharmacology and Toxicology, Faculty of Pharmacy, Cairo University, Cairo, Egypt
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Saeed A, Herlitz H, Nowakowska-Fortuna E, Nilsson U, Alhadad A, Jensen G, Mattiasson I, Lindblad B, Gottsäter A, Guron G. Oxidative Stress and Endothelin-1 in Atherosclerotic Renal Artery Stenosis and Effects of Renal Angioplasty. Kidney Blood Press Res 2011; 34:396-403. [DOI: 10.1159/000328732] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2011] [Accepted: 04/13/2011] [Indexed: 11/19/2022] Open
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Kumbhani DJ, Bavry AA, Harvey JE, de Souza R, Scarpioni R, Bhatt DL, Kapadia SR. Clinical outcomes after percutaneous revascularization versus medical management in patients with significant renal artery stenosis: a meta-analysis of randomized controlled trials. Am Heart J 2011; 161:622-630.e1. [PMID: 21392620 DOI: 10.1016/j.ahj.2010.12.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2010] [Accepted: 12/06/2010] [Indexed: 11/25/2022]
Abstract
BACKGROUND We sought to systematically evaluate whether percutaneous revascularization is associated with additional clinical benefit in patients with renal artery stenosis (RAS) as compared with medical management alone. METHODS We included randomized controlled trials that compared percutaneous revascularization in addition to medical therapy versus medical management alone in patients with RAS. Six trials with 1,208 patients were included. RESULTS At a mean follow-up of 29 months, there was no change in systolic blood pressure (weighted mean difference [WMD] = 1.20 mm Hg, 95% CI -1.18 to 3.58 mm Hg) or diastolic blood pressure (WMD = -1.60 mm Hg, 95% CI -4.22 to 1.02 mm Hg) from baseline in the percutaneous revascularization arm compared with the medical management arm. There was a reduction in the mean number of antihypertensive medications (WMD = -0.26, 95% CI -0.39 to -0.13, P < .001), but not serum creatinine (WMD = -0.14 mg/dL, 95% CI -0.29 to 0.007 mg/dL), in the percutaneous revascularization arm at the end of follow-up. Percutaneous revascularization was not associated with a significant difference in all-cause mortality (relative risk [RR] = 0.96, 95% CI 0.74-1.25), congestive heart failure (RR = 0.79, 95% CI 0.56-1.13), stroke (RR = 0.86, 95% CI 0.50-1.47), or worsening renal function (RR = 0.91, 95% CI 0.67-1.23) as compared with medical management. CONCLUSIONS In patients with RAS, percutaneous renal revascularization in addition to medical therapy may result in a lower requirement for antihypertensive medications, but not with improvements in serum creatinine or clinical outcomes, as compared with medical management over an intermediate period of follow-up. Further studies are needed to identify the appropriate patient population most likely to benefit from its use.
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Abstract
OBJECTIVE To assess the association of single-nucleotide polymorphisms (SNPs) in genes codifying for antioxidant enzymes to blood pressure (BP) values and risk of hypertension. METHODS Population-based study including 1388 participants (704 women) older than 18 years in which 300 were untreated hypertensive patients. In 335 untreated hypertensive patients referred to one hypertension clinic, the study was replicated. Thirty-five SNP throughout 13 genes were analyzed using SNPlex. In a subgroup of hypertensive patients, the amount of 8-oxo-deoxyguanosine and GPX activity levels was measured in mononuclear cells. RESULTS In the general population, genotypes with the G allele of the c.172G>A polymorphism in the SOD3 gene and those with the T allele of the c.-20C>T polymorphism in the CAT gene were associated with significant lower values of BP. Likewise, these genotypes were associated with less risk for hypertension after adjusting for confounder variables. Haplotypes in both genes increased the strength of associations. In the hypertensive patients, the same alleles of the two polymorphisms were associated with lower BP values too. In addition, two others, the CT-TT genotypes of the c.891C>T polymorphism in the GPX1 gene and the CT-CC genotypes of the c.-793T>C polymorphism of the TXN gene were also significantly associated to lower BP values. Furthermore, the CC genotype of the c.891C>T polymorphism in the GPX1 gene was associated with higher values of 8-oxo-dG and GPX activity levels as compared to those for the CT-TT genotype. CONCLUSIONS The results of the present study support the influence of antioxidant enzyme genes in BP values and hypertension risk.
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88
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Grossman RC. Experimental models of renal disease and the cardiovascular system. Open Cardiovasc Med J 2010; 4:257-64. [PMID: 21258578 PMCID: PMC3024648 DOI: 10.2174/1874192401004010257] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2010] [Revised: 09/29/2010] [Accepted: 10/04/2010] [Indexed: 12/02/2022] Open
Abstract
Cardiovascular disease is a leading cause of death among patients with end stage renal failure. Animal models have played a crucial role in teasing apart the complex pathological processes involved. This review discusses the principles of using animal models, the history of their use in the study of renal hypertension, the controversies arising from experimental models of non-hypertensive uraemic cardiomyopathy and the lessons learned from these models, and highlights important areas of future research in this field, including de novo cardiomyopathy secondary to renal transplantation.
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Affiliation(s)
- Rebecca C Grossman
- Department of Cellular Pathology, Royal Free Hospital, London NW3 2QG, London, United Kingdom
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89
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Abstract
Renovascular disease remains among the most prevalent and important causes of secondary hypertension and renal dysfunction. Many lesions reduce perfusion pressure including fibromuscular diseases and renal infarction, but most are caused by atherosclerotic disease. Epidemiologic studies establish a strong association between atherosclerotic renal-artery stenosis (ARAS) and cardiovascular risk. Hypertension develops in patients with renovascular disease from a complex set of pressor signals, including activation of the renin-angiotensin system (RAS), recruitment of oxidative stress pathways, and sympathoadrenergic activation. Although the kidney maintains function over a broad range of autoregulation, sustained reduction in renal perfusion leads to disturbed microvascular function, vascular rarefaction, and ultimately development of interstitial fibrosis. Advances in antihypertensive drug therapy and intensive risk factor management including smoking cessation and statin therapy can provide excellent blood pressure control for many individuals. Despite extensive observational experience with renal revascularization in patients with renovascular hypertension, recent prospective randomized trials fail to establish compelling benefits either with endovascular stents or with surgery when added to effective medical therapy. These trials are limited and exclude many patients most likely to benefit from revascularization. Meaningful recovery of kidney function after revascularization is limited once fibrosis is established. Recent experimental studies indicate that mechanisms allowing repair and regeneration of parenchymal kidney tissue may lead to improved outcomes in the future. Until additional staging tools become available, clinicians will be forced to individualize therapy carefully to optimize the potential benefits regarding both blood pressure and renal function for such patients.
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90
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The uncertain value of renal artery interventions: where are we now? JACC Cardiovasc Interv 2010; 2:175-82. [PMID: 19463422 DOI: 10.1016/j.jcin.2008.12.008] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Revised: 12/05/2008] [Accepted: 12/11/2008] [Indexed: 11/23/2022]
Abstract
Improved technology for detection of and endovascular procedures for renal artery stenosis due to atherosclerosis has been associated with increases in renal artery intervention. Hypertension with accelerated target organ injury, reduced kidney function, and episodic circulatory congestion in patients with renovascular disease predict reduced patient survival. Recent studies indicate that activation of pressor mechanisms depends upon hemodynamic gradients that are often overrated by visual estimates. Although activation of the renin-angiotensin system initiates renovascular hypertension, additional mechanisms perpetuate vascular remodeling and kidney injury that may not depend upon large vessel occlusion. Major advances in medical therapy have led to initiation of at least 4 major prospective trials comparing optimal medical therapy with or without stenting. Up to now, outcome data fail to support broad application of renal revascularization, including results from a recent large, prospective trial from the United Kingdom, despite small groups of patients that experience major clinical benefit. The ambiguity of these results partly reflect poor characterization of the severity of vascular lesions and competing risks within the population related to aging and pre-existing disease. Many patients currently undergoing renal artery interventions derive little net benefit and some are exposed to significant complications, including atheroembolic disease. Determining the appropriate role for renal artery interventions will depend on developing better methods for judging the role of large vessel occlusive disease regarding tissue oxygenation, activation of profibrotic pathways, and irreversible injury in the post-stenotic kidney.
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91
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Cabral PD, Silva GB, Baigorria ST, Juncos LA, Juncos LI, García NH. 8-iso-prostaglandin-F2α stimulates chloride transport in thick ascending limbs: role of cAMP and protein kinase A. Am J Physiol Renal Physiol 2010; 299:F1396-400. [PMID: 20861077 DOI: 10.1152/ajprenal.00225.2010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Salt reabsorption by the loop of Henle controls NaCl handling and blood pressure regulation. Increased oxidative stress stimulates NaCl transport in one specific segment of the loop of Henle called the thick ascending limb (TAL). The isoprostane 8-iso-prostaglandin-F2α (8-iso-PGF2α) is one of the most abundant nonenzymatic lipid oxidation products and has been implicated in the development of hypertension. However, it is not known whether 8-iso-PGF2α regulates transport or the mechanisms involved. Because protein kinase A (PKA) stimulates NaCl transport in several nephron segments, we hypothesized that 8-iso-PGF2α increases NaCl transport in the cortical TAL (cTAL) via a PKA-dependent mechanism. We examined the effect of luminal 8-iso-PGF2α on NaCl transport by measuring chloride absorption (J(Cl)) in isolated microperfused cTALs. Adding 8-iso-PGF2α to the lumen increased J(Cl) by 54% (from 288.7 ± 30.6 to 446.5 ± 44.3 pmol·min(-1)·mm(-1); P < 0.01), while adding it to the bath enhanced J(Cl) by 35% (from 236.3 ± 35.3 to 319.2 ± 39.8 pmol·min(-1)·mm(-1); P < 0.05). This stimulation was blocked by Na-K-2Cl cotransporter inhibition. Next, we tested the role of cAMP. Basal cAMP in the cTAL was 18.6 ± 1.6 fmol·min(-1)·mm(-1), and 8-iso-PGF2α raised it to 35.1 ± 1.4 fmol·min(-1)·mm(-1), an increase of 94% (P < 0.01). Because cAMP stimulates PKA, we measured J(Cl) using the PKA-selective inhibitor H89. In the presence of H89 (10 μM), 8-iso-PGF2α failed to increase transport regardless of whether it was added to the lumen (216.1 ± 16.7 vs. 209.7 ± 23.8 pmol·min(-1)·mm(-1); NS) or the bath (150.4 ± 32.9 vs. 127.1 ± 28.6 pmol·min(-1)·mm(-1); NS). We concluded that 8-iso-PGF2α stimulates cAMP and increases Cl transport in cTALs via a PKA-dependent mechanism.
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Affiliation(s)
- Pablo D Cabral
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, Michigan, USA
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92
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Gayen JR, Zhang K, RamachandraRao SP, Mahata M, Chen Y, Kim HS, Naviaux RK, Sharma K, Mahata SK, O'Connor DT. Role of reactive oxygen species in hyperadrenergic hypertension: biochemical, physiological, and pharmacological evidence from targeted ablation of the chromogranin a (Chga) gene. ACTA ACUST UNITED AC 2010; 3:414-25. [PMID: 20729505 DOI: 10.1161/circgenetics.109.924050] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
BACKGROUND Oxidative stress, an excessive production of reactive oxygen species (ROS) outstripping antioxidant defense mechanisms, occurs in cardiovascular pathologies, including hypertension. In the present study, we used biochemical, physiological, and pharmacological approaches to explore the role of derangements of catecholamines, ROS, and the endothelium-derived relaxing factor nitric oxide (NO(•)) in the development of a hyperadrenergic model of hereditary hypertension: targeted ablation (knockout [KO]) of chromogranin A (Chga) in the mouse. METHODS AND RESULTS Homozygous ⁻(/)⁻ Chga gene knockout (KO) mice were compared with wild-type (WT, +/+) control mice. In the KO mouse, elevations of systolic and diastolic blood pressure were accompanied by not only elevated catecholamine (norepinephrine and epinephrine) concentrations but also increased ROS (H₂O₂) and isoprostane (an index of lipid peroxidation), as well as depletion of NO(•). Renal transcript analyses implicated changes in Nox1/2, Xo/Xdh, and Sod1,2 mRNAs in ROS elevation by the KO state. KO alterations in blood pressure, catecholamines, H₂O₂, isoprostane, and NO(•) could be abrogated or even normalized (rescued) by either sympathetic outflow inhibition (with clonidine) or NADPH oxidase inhibition (with apocynin). In cultured renal podocytes, H₂O₂ production was substantially augmented by epinephrine (probably through β₂-adrenergic receptors) and modestly diminished by norepinephrine (probably through α₁-adrenergic receptors). CONCLUSIONS ROS appear to play a necessary role in the development of hyperadrenergic hypertension in this model, in a process mechanistically linking elevated blood pressure with catecholamine excess, renal transcriptional responses, ROS elevation, lipid peroxidation, and NO(•) depletion. Some of the changes appear to be dependent on transcription, whereas others are immediate. The cycle could be disrupted by inhibition of either sympathetic outflow or NADPH oxidase. Because common genetic variation at the human CHGA locus alters BP, the results have implications for antihypertensive treatment as well as prevention of target-organ consequences of the disease. The results document novel pathophysiological links between the adrenergic system and oxidative stress and suggest new strategies to probe the role and actions of ROS within this setting.
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Affiliation(s)
- Jiaur R Gayen
- University of California at San Diego, La Jolla, USA
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93
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Revascularization of swine renal artery stenosis improves renal function but not the changes in vascular structure. Kidney Int 2010; 78:1110-8. [PMID: 20463652 DOI: 10.1038/ki.2010.142] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Renal revascularization by percutaneous transluminal angioplasty improves blood pressure and stenotic kidney function in selected groups of patients, but the reversibility of intrarenal and microvascular remodeling remains unknown. Here, we tested the hypothesis that renal angioplasty improves the function and structure of renal microcirculation in experimental chronic renal artery stenosis. Stenotic kidney function, hemodynamics, and endothelial function were assessed in vivo in pigs after 10 weeks of unilateral renal artery stenosis. Renal microvascular remodeling, angiogenic pathways, and fibrosis were measured ex vivo. Angioplasty and stenting carried out 4 weeks before measurement decreased blood pressure, improved glomerular filtration rate, and improved microvascular endothelial function. It also promoted the expression of angiogenic factors and decreased renal apoptosis due to stenosis, compared with a sham intervention. The spatial density of renal microvessels, however, was partially improved after angioplasty. Renal blood flow was incompletely restored compared with the kidneys of sham-treated animals, as was interstitial fibrosis. Renal microvascular media-to-lumen ratio remained unchanged by angioplasty. Thus, our study shows that revascularization of a stenotic renal artery restores the glomerular filtration rate and renal endothelial function 4 weeks later. Renal hemodynamics and structure, however, are incompletely resolved.
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94
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Chronic antioxidant treatment improves arterial renovascular hypertension and oxidative stress markers in the kidney in Wistar rats. Am J Hypertens 2010; 23:473-80. [PMID: 20186128 DOI: 10.1038/ajh.2010.11] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Sympathetic vasomotor hyperactivity and baroreflex dysfunction are involved in the development and maintenance of renovascular arterial hypertension. We hypothesized that angiotensin (Ang) II-dependent oxidative stress contributes to the pathophysiology of the two-kidney, one-clip (2K-1C) model. METHODS The mean arterial pressure (MAP), baroreflex, and renal sympathetic nerve activity (rSNA) were evaluated after chronic administration of an antioxidant, vitamin C (vitC 150 mg/kg/day) in male Wistar 2K-1C rats. Additionally, the mRNA levels of Ang II subtype 1 receptor (AT(1)R), NAD(P)H oxidase subunits (p47phox and gp91phox), and major antioxidant enzymes were evaluated in the renal cortex. RESULTS After vitC treatment, the MAP (170 +/- 4 vs. 133 +/- 6 mm Hg; P < 0.05) and rSNA (161 +/- 5 vs. 118 +/- 12 spikes/s; P < 0.05) were significantly reduced only in the 2K-1C group. VitC improved the baroreflex control of heart rate (HR) and rSNA. The expression of AT(1)R, p47phox, and gp91phox was elevated (51, 184, and 132%, respectively) in the clipped kidney of 2K-1C group. VitC downregulated AT(1)R in the clipped kidney (31%). Catalase (CAT) expression was reduced in clipped (70%) and nonclipped (83%) kidneys of 2K-1C rats. VitC treatment augmented the expression of glutathione peroxidase (GPx) in both clipped (185%) and nonclipped (212%) kidneys of the 2K-1C group. CONCLUSIONS The present study suggests a role for oxidative stress in the cardiovascular and sympathetic alterations in renovascular hypertension, associated with changes in the expression of AT(1)R, NAD(P)H oxidase subunits, and antioxidant enzymes in the kidney.
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95
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Abstract
Hypertension reigns as a leading cause of cardiovascular morbidity and mortality worldwide. Excessive reactive oxygen species (ROS) have emerged as a central common pathway by which disparate influences may induce and exacerbate hypertension. Potential sources of excessive ROS in hypertension include nicotinamide adenine dinucleotide phosphate (NADPH) oxidase, mitochondria, xanthine oxidase, endothelium-derived NO synthase, cyclooxygenase 1 and 2, cytochrome P450 epoxygenase, and transition metals. While a significant body of epidemiological and clinical data suggests that antioxidant-rich diets reduce blood pressure and cardiovascular risk, randomized trials and population studies using natural antioxidants have yielded disappointing results. The reasons behind this lack of efficacy are not completely clear, but likely include a combination of (1) ineffective dosing regimens, (2) the potential pro-oxidant capacity of some of these agents, (3) selection of subjects less likely to benefit from antioxidant therapy (too healthy or too sick), and (4) inefficiency of nonspecific quenching of prevalent ROS versus prevention of excessive ROS production. Commonly used antioxidants include Vitamins A, C and E, L-arginine, flavanoids, and mitochondria-targeted agents (Coenzyme Q10, acetyl-L-carnitine, and alpha-lipoic acid). Various reasons, including incomplete knowledge of the mechanisms of action of these agents, lack of target specificity, and potential interindividual differences in therapeutic efficacy preclude us from recommending any specific natural antioxidant for antihypertensive therapy at this time. This review focuses on recent literature evaluating naturally occurring antioxidants with respect to their impact on hypertension.
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Affiliation(s)
- Tinoy J Kizhakekuttu
- Department of Medicine, Cardiovascular Medicine Division and Department of Pharmacology, Medical College of Wisconsin, Milwaukee, WI 53226, USA
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96
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Gómez-Roso M, Montero MJ, Carrón R, Sevilla MA. Cardiovascular changes in spontaneously hypertensive rats are improved by chronic treatment with zofenopril. Br J Pharmacol 2010; 158:1911-21. [PMID: 19917062 DOI: 10.1111/j.1476-5381.2009.00491.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
BACKGROUND AND PURPOSE The aim of this study was to investigate the effect of chronic treatment with antihypertensive and non-antihypertensive doses of zofenopril on cardiovascular changes in spontaneously hypertensive rats (SHR). EXPERIMENTAL APPROACH Male SHR were treated with 0.5 or 10 mg kg(-1) per day of zofenopril (Z(0.5) and Z(10)) for 3 months. SHR and Wistar-Kyoto rats (WKY) receiving vehicle were used as controls. Systolic blood pressure was measured using the tail cuff method. Left ventricular weight/body weight ratio was calculated as cardiac hypertrophy index. Angiotensin converting enzyme (ACE) activity was determined in plasma and tissues by a fluorimetric method. Vascular reactivity was evaluated on aortic rings by acetylcholine and sodium nitroprusside relaxations. Effects on vascular structure were assessed by lumen diameter, wall thickness and medial cross-sectional area determination. Superoxide anion generation was quantified using lucigenin-amplified chemiluminescence in aorta. RESULTS Long-term daily administration of zofenopril (10 mg kg(-1)) to SHR reduced blood pressure to WKY values, decreased cardiac hypertrophy, improved the acetylcholine-induced relaxant response and reversed the vascular remodelling. ACE inhibition and antioxidant activity were involved in these effects. 0.5 mg kg(-1) per day of zofenopril slightly modified blood pressure and the other effects were weaker. CONCLUSIONS AND IMPLICATIONS Antihypertensive effects of chronic treatment with zofenopril were accompanied by recovery of endothelial function and improvement of cardiovascular structure. Low-dose zofenopril had little effect on blood pressure, with some benefits on cardiovascular structure and function. Inhibition of ACE and antioxidant activity were involved in these effects.
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Affiliation(s)
- M Gómez-Roso
- Departamento de Fisiología y Farmacología, Facultad de Farmacia, Universidad de Salamanca, Salamanca, Spain
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97
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Lavi R, Zhu XY, Chade AR, Lin J, Lerman A, Lerman LO. Simvastatin decreases endothelial progenitor cell apoptosis in the kidney of hypertensive hypercholesterolemic pigs. Arterioscler Thromb Vasc Biol 2010; 30:976-83. [PMID: 20203299 DOI: 10.1161/atvbaha.109.201475] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
OBJECTIVE Hypertension and hypercholesterolemia might interfere with renal repair mechanisms. We hypothesized that simvastatin improves the survival of endothelial progenitor cells (EPC) in the renal microenvironment imposed by concurrent renovascular hypertension and dietary hypercholesterolemia (HTC). METHODS AND RESULTS Pigs were studied after 12 weeks of no intervention (n=6), HTC (n=6), or HTC+ oral simvastatin supplementation (80 mg/day, n=5). EPC were also isolated and studied in vitro after exposure to the proapoptotic oxidized low-density lipoprotein with or without coincubation with simvastatin. Renal hemodynamics, function, and endothelial function were evaluated in vivo, and the number of CD34+/KDR+ EPC, apoptosis, oxidative stress, inflammation, and fibrosis in renal tissue studied ex vivo. Compared with normal kidney, the HTC kidney showed endothelial dysfunction and increased oxidative stress, interstitial macrophage filtration, and fibrosis. The number of EPC in the kidney increased, as did their apoptosis (0.85+/-0.24% versus 0.22+/-0.07%, P<0.05 versus normal). Simvastatin did not affect blood pressure, cholesterol levels, basal renal function, or number of renal EPC in HTC, but it improved endothelial function; blunted renal oxidative stress, inflammation, and fibrosis; and attenuated EPC apoptosis (to 0.37+/-0.09%, P<0.05 versus HTC). Simvastatin also significantly decreased oxidized low-density lipoprotein-induced EPC apoptosis in vitro. CONCLUSION EPC are recruited but undergo apoptosis in the HTC kidney, likely because of a hostile microenvironment. Simvastatin rescues renal repair mechanisms in HTC and counteracts renal damage, which may account for its protective effects on the kidney during exposure to cardiovascular risk factors.
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Affiliation(s)
- Ronit Lavi
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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98
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Pereira TMC, Balarini CM, Silva IV, Cabral AM, Vasquez EC, Meyrelles SS. Endogenous angiotensin II modulates nNOS expression in renovascular hypertension. Braz J Med Biol Res 2010; 42:685-91. [PMID: 19578649 DOI: 10.1590/s0100-879x2009000700014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2008] [Accepted: 05/06/2009] [Indexed: 01/13/2023] Open
Abstract
Nitric oxide (NO) influences renal blood flow mainly as a result of neuronal nitric oxide synthase (nNOS). Nevertheless, it is unclear how nNOS expression is modulated by endogenous angiotensin II, an inhibitor of NO function. We tested the hypothesis that the angiotensin II AT1 receptor and oxidative stress mediated by NADPH oxidase contribute to the modulation of renal nNOS expression in two-kidney, one-clip (2K1C) hypertensive rats. Experiments were performed on male Wistar rats (150 to 170 g body weight) divided into 2K1C (N = 19) and sham-operated (N = 19) groups. nNOS expression in kidneys of 2K1C hypertensive rats (N = 9) was compared by Western blotting to that of 2K1C rats treated with low doses of the AT1 antagonist losartan [10 mg x kg(-1) x day(-1); N = 5] or the superoxide scavenger tempol [0.2 mmol x kg(-1) x day(-1); N = 5], which still remain hypertensive. After 28 days, nNOS expression was significantly increased by 1.7-fold in the clipped kidneys of 2K1C rats and by 3-fold in the non-clipped kidneys of 2K1C rats compared with sham rats, but was normalized by losartan. With tempol treatment, nNOS expression increased 2-fold in the clipped kidneys and 1.4-fold in the non-clipped kidneys compared with sham rats. The changes in nNOS expression were not followed by changes in the enzyme activity, as measured indirectly by the cGMP method. In conclusion, AT1 receptors and oxidative stress seem to be primary stimuli for increased nNOS expression, but this up-regulation does not result in higher enzyme activity.
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Affiliation(s)
- T M C Pereira
- Laboratório de Transgenes e Controle Cardiovascular, Centro de Ciências da Saúde, Universidade Federal do Espírito Santo, 29043-900 Vitória, ES, Brasil
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99
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Textor SC, McKusick MM, Misra S, Glockner J. Timing and selection for renal revascularization in an era of negative trials: what to do? Prog Cardiovasc Dis 2010; 52:220-8. [PMID: 19917333 DOI: 10.1016/j.pcad.2009.10.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Management of atherosclerotic renal artery stenosis has become more complex with advances in both medical therapy and endovascular procedures. Results from recent trials fail to demonstrate major benefits of endovascular stenting in addition to optimal medical therapy. The general applicability of these results to many patients is limited by short-term follow-up and selection biases in recruitment. Many patients at highest risk were excluded from these studies and some were included with trivial lesions. Identification of patients with hemodynamically significant lesions remains a challenge and has led to more stringent criteria for Doppler ultrasound, measurement of translesional gradients and quantitative angiography. Although many patients can now be managed with medical therapy, it should be recognized that long-term reduction in antihypertensive drug requirements and recovery of kidney function are limited to those undergoing renal revascularization. As with any major vascular lesion, follow-up for disease stability and/or progression is essential. The ambiguity of present trial data may lead some to overlook selected subgroups that would benefit from restoring renal blood supply through revascularization. Further studies to more precisely identify kidneys that can recover function and/or are beyond meaningful recovery are essential. Considering the comorbid risks for the atherosclerotic population, it will remain imperative for clinicians to consider the hazards, costs and benefits carefully for each patient to determine the role and timing for both medical therapy and revascularization.
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Affiliation(s)
- Stephen C Textor
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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100
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Iliescu R, Fernandez SR, Kelsen S, Maric C, Chade AR. Role of renal microcirculation in experimental renovascular disease. Nephrol Dial Transplant 2009; 25:1079-87. [PMID: 19934087 DOI: 10.1093/ndt/gfp605] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Renal artery stenosis (RAS) causes renal injury partly via microvascular (MV) endothelial dysfunction and damage. Vascular endothelial growth factor (VEGF) is crucial for preservation of microvasculature and promotes vascular proliferation and endothelial repair. We have previously shown that MV rarefaction is associated with decreased VEGF in the kidney exposed to chronic RAS, accompanied by deteriorated renal function and fibrosis. We hypothesized that preserving the renal microcirculation in the stenotic kidney will halt the progression of renal damage. METHODS Unilateral RAS was induced in 16 pigs. In eight, VEGF (0.05 micrograms/kg) was infused intra-renally at the onset of RAS. After 6 weeks, single-kidney haemodynamics and function were assessed using in vivo multi-detector computed tomography (CT). Renal microvessels, angiogenic pathways and morphology were investigated ex vivo using micro-CT, real-time PCR and histology. RESULTS Blood pressure and degree of RAS was similar in RAS and RAS + VEGF pigs. Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were reduced in RAS compared to Normal (221.1 +/- 46.5 and 29.9 +/- 3.8 vs. 522.5 +/- 60.9 and 49.3 +/- 3.4 mL/min, respectively, P < 0.05), accompanied by decreased cortical MV density and increased renal fibrosis. Pre-emptive administration of VEGF preserved MV architecture, attenuated fibrosis and normalized RBF and GFR (510.8 +/- 50.9 and 39.9.1 +/- 4.1 mL/min, P = not significant vs. Normal). CONCLUSIONS This study underscores the importance of the renal microcirculation in renovascular disease. Intra-renal administration of VEGF preserved renal MV architecture and function of the stenotic kidney, which in turn preserved renal haemodynamics and function and decreased renal fibrosis. These observations suggest that preventing renal MV loss may be a potential target for therapeutic approaches for patients with chronic renovascular disease.
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Affiliation(s)
- Radu Iliescu
- The Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, MS, USA
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