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Eirin A, Chade AR, Lerman LO. Kidney Intrinsic Mechanisms as Novel Targets in Renovascular Hypertension. Hypertension 2024; 81:206-217. [PMID: 37869904 PMCID: PMC10842320 DOI: 10.1161/hypertensionaha.123.21362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2023]
Abstract
Almost a hundred years have passed since obstruction of the renal artery has been recognized to raise blood pressure. By now chronic renovascular disease (RVD) due to renal artery stenosis is recognized as a major source of renovascular hypertension and renal disease. In some patients, RVD unaccompanied by noteworthy renal dysfunction or blood pressure elevation may be incidentally identified during peripheral angiography. Nevertheless, in others, RVD might present as a progressive disease associated with diffuse atherosclerosis, leading to loss of renal function, renovascular hypertension, hemodynamic compromise, and a magnified risk for cardiovascular morbidity and mortality. Atherosclerotic RVD leads to renal atrophy, inflammation, and hypoxia but represents a potentially treatable cause of chronic renal failure because until severe fibrosis sets in the ischemic kidney, it retains a robust potential for vascular and tubular regeneration. This remarkable recovery capacity of the kidney begs for early diagnosis and treatment. However, accumulating evidence from both animal studies and randomized clinical trials has convincingly established the inadequate efficacy of renal artery revascularization to fully restore renal function or blood pressure control and has illuminated the potential of therapies targeted to the ischemic renal parenchyma to instigate renal regeneration. Some of the injurious mechanisms identified as potential therapeutic targets included oxidative stress, microvascular disease, inflammation, mitochondrial injury, and cellular senescence. This review recapitulates the intrinsic mechanisms that orchestrate renal damage and recovery in RVD and can be harnessed to introduce remedial opportunities.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Alejandro R. Chade
- Department of Medical Pharmacology and Physiology, University of Missouri-Columbia, MO
| | - Lilach O. Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Damianaki A, Hendriks-Balk M, Brito W, Polychronopoulou E, Theiler K, Maillard M, Maurer J, Eugster P, Pruijm M, Wuerzner G. Contrast-enhanced ultrasonography reveals a lower cortical perfusion and a decreased renal flow reserve in hypertensive patients. Nephrol Dial Transplant 2024; 39:242-250. [PMID: 37553142 PMCID: PMC10828216 DOI: 10.1093/ndt/gfad158] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Indexed: 08/10/2023] Open
Abstract
BACKGROUND Microvascular structural alteration and dysfunction is a hallmark of arterial hypertension. So far, the visualization and the quantification of renal microcirculation in humans has been hampered by the lack of non-nephrotoxic and non-invasive radiologic techniques. Contrast-enhanced ultrasonography (CEUS) is an appealing method to investigate renal microcirculation and has not been investigated in this setting. We aimed to compare renal microcirculation in normotensive (NT) and hypertensive (HT) participants using CEUS at rest and during a sympathetic stress test. METHODS We measured the renal perfusion index (PI, primary outcome), the renal resistive index (RRI), beat-to-beat systemic hemodynamics and plasma catecholamines before and during a 2-min cold pressor test (CPT) in NT and HT participants. Linear mixed model analysis was used to compare the effect of the CPT on the variables of interest. RESULTS Seventy-three participants (32 HT) with normal kidney function were included. HT participants had a lower baseline PI compared with NT participants [median (interquartile range) 1476 (959-2155) arbitrary units (a.u.) vs 2062 (1438-3318) a.u., P < .001]. The CPT increased blood pressure, heart rate and catecholamines in all participants. The increase in PI observed in NT during the CPT was blunted in HT [+504 (117-920) a.u. vs +1159 (678-2352) a.u in NT, interaction P = .013]. Age, sex and body mass index did not modify these results. CONCLUSIONS HT patients had a lower basal renal cortical perfusion. During the cold pressor test, HT participants had a smaller increase in the PI, suggesting that renal cortical flow reserve is impaired.
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Affiliation(s)
- Aikaterini Damianaki
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Mariëlle Hendriks-Balk
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Wendy Brito
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Erietta Polychronopoulou
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Kenji Theiler
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Marc Maillard
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Jonathan Maurer
- Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Philippe Eugster
- Service of Clinical Pharmacology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Menno Pruijm
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
| | - Grégoire Wuerzner
- Service of Nephrology and Hypertension, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland
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Ebrahimi B, Gandhi D, Alsaeedi MH, Lerman LO. Patterns of cortical oxygenation may predict the response to stenting in subjects with renal artery stenosis: A radiomics-based model. J Cardiovasc Magn Reson 2024; 26:100993. [PMID: 38218433 PMCID: PMC11211233 DOI: 10.1016/j.jocmr.2024.100993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 01/03/2024] [Indexed: 01/15/2024] Open
Abstract
BACKGROUND Percutaneous-transluminal renal angioplasty (PTRA) and stenting aim to halt the progression of kidney disease in patients with renal artery stenosis (RAS), but its outcome is often suboptimal. We hypothesized that a model incorporating markers of renal function and oxygenation extracted using radiomics analysis of blood oxygenation-level dependent (BOLD)-MRI images may predict renal response to PTRA in swine RAS. MATERIALS AND METHODS Twenty domestic pigs with RAS were scanned with CT and BOLD MRI before and 4 weeks after PTRA. Stenotic (STK) and contralateral (CLK) kidney volume, blood flow (RBF), and glomerular filtration rate (GFR) were determined, and BOLD-MRI R2 * maps were generated before and after administration of furosemide, a tubular reabsorption inhibitor. Radiomics features were extracted from pre-PTRA BOLD maps and Robust features were determined by Intraclass correlation coefficients (ICC). Prognostic models were developed to predict post-PTRA renal function based on the baseline functional and BOLD-radiomics features, using Lasso-regression for training, and testing with resampling. RESULTS Twenty-six radiomics features passed the robustness test. STK oxygenation distribution pattern did not respond to furosemide, whereas in the CLK radiomics features sensitive to oxygenation heterogeneity declined. Radiomics-based model predictions of post-PTRA GFR (r = 0.58, p = 0.007) and RBF (r = 0.68; p = 0.001) correlated with actual measurements with sensitivity and specificity of 92% and 67%, respectively. Models were unsuccessful in predicting post-PTRA systemic measures of renal function. CONCLUSIONS Several radiomics features are sensitive to cortical oxygenation patterns and permit estimation of post-PTRA renal function, thereby distinguishing subjects likely to respond to PTRA and stenting.
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Affiliation(s)
- Behzad Ebrahimi
- Department of Radiation and Cellular Oncology, University of Chicago, IL, 60637, USA
| | - Deep Gandhi
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Mina H Alsaeedi
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA.
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Farooqui N, Mohan A, Isik B, Goksu BB, Thaler R, Zhu XY, Krier JD, Saadiq IM, Ferguson CM, Jordan KL, Tang H, Textor SC, Hickson LTJ, van Wijnen AJ, Eirin A, Lerman LO, Herrmann SM. Effect of Hypoxia Preconditioning on the Regenerative Capacity of Adipose Tissue Derived Mesenchymal Stem Cells in a Model of Renal Artery Stenosis. Stem Cells 2023; 41:50-63. [PMID: 36250949 PMCID: PMC9887092 DOI: 10.1093/stmcls/sxac073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/26/2022] [Indexed: 02/02/2023]
Abstract
Atherosclerotic renal artery stenosis (ARAS) is associated with irreversible parenchymal renal disease and regenerative stem cell therapies may improve renal outcomes. Hypoxia preconditioning (HPC) may improve the regenerative functions of adipose tissue-derived mesenchymal stem cells (AMSC) by affecting DNA 5-hydroxymethylcytosine (5hmC) marks in angiogenic genes. Here, we investigated using a porcine ARAS model, whether growth of ARAS AMSCs in hypoxia (Hx) versus normoxia (Nx) would enhance renal tissue repair, and comprehensively analyze how HPC modifies DNA hydroxymethylation compared to untreated ARAS and healthy/normal pigs (n=5 each). ARAS pigs exhibited elevated serum cholesterol, serum creatinine and renal artery stenosis, with a concomitant decrease in renal blood flow (RBF) and increased blood pressure (BP) compared to healthy pigs. Renal artery injection of either autologous Nx or Hx AMSCs improved diastolic BP, reduced kidney tissue fibrosis, and inflammation (CD3+ T-cells) in ARAS pigs. In addition, renal medullary hypoxia significantly lowered with Nx but not Hx AMSC treatment. Mechanistically, levels of epigenetic 5hmC marks (which reflect gene activation) estimated using DNA immunoprecipitation technique were elevated in profibrotic and inflammatory genes in ARAS compared with normal AMSCs. HPC significantly reduced 5hmC levels in cholesterol biosynthesis and oxidative stress response pathways in ARAS AMSCs. Thus, autologous AMSCs improve key renovascular parameters and inflammation in ARAS pigs, with HPC mitigating pathological molecular effects on inflammatory and profibrotic genes which may play a role in augmenting regenerative capacity of AMSCs.
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Affiliation(s)
- Naba Farooqui
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Arjunmohan Mohan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Busra Isik
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Busra B Goksu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Roman Thaler
- Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN, USA
| | - Xiang Yang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - James D Krier
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Ishran M Saadiq
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | - Kyra L Jordan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Hui Tang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Stephen C Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - La Tonya J Hickson
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | - Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Sandra M Herrmann
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Jiang K, Ferguson CM, Grimm RC, Zhu X, Glockner JF, Lerman LO. Reliable Assessment of Swine Renal Fibrosis Using Quantitative Magnetization Transfer Imaging. Invest Radiol 2022; 57:334-342. [PMID: 34935650 PMCID: PMC8986560 DOI: 10.1097/rli.0000000000000843] [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: 01/20/2023]
Abstract
OBJECTIVES Quantitative magnetization transfer (qMT) is useful for measurement of murine renal fibrosis at high and ultrahigh field strengths. However, its utility at clinical field strengths and in human-like kidneys remains unknown. We tested the hypothesis that qMT would successfully detect fibrosis in swine kidneys with unilateral renal artery stenosis (RAS) at 3.0 T. METHODS The qMT protocol is composed of MT scans with variable flip angles and offset frequencies, and of B0, B1, and T1 mapping. Pigs were scanned 10 weeks after RAS or control. A 2-pool model was used to fit the bound pool fraction f of the renal cortex (CO) and outer medulla (OM). Then qMT-derived f in 5 normal and 10 RAS pigs was compared with histological fibrosis determined using Masson's trichrome staining and to renal perfusion assessed with computed tomography. RESULTS The qMT 2-pool model provided accurate fittings of data collected on swine kidneys. Stenotic kidneys showed significantly elevated f in both the CO (9.8% ± 2.7% vs 6.4% ± 0.9%, P = 0.002) and OM (7.6% ± 2.2% vs 4.7% ± 1.1%, P = 0.002), as compared with normal kidneys. Histology-measured renal fibrosis and qMT-derived f correlated directly in both the cortex (Pearson correlation coefficient r = 0.93, P < 0.001) and OM (r = 0.84, P = 0.002), and inversely with stenotic kidney perfusion (r = 0.85, P = 0.002). CONCLUSIONS This study demonstrates the feasibility of qMT for measuring fibrosis in human-like swine kidneys, and the association between tissue macromolecule content and renal perfusion. Therefore, qMT may be useful as a tool for noninvasive assessment of renal fibrosis in subjects with RAS at clinical field strengths.
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Affiliation(s)
- Kai Jiang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | | | - Roger C. Grimm
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiangyang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - James F. Glockner
- Department of Diagnostic Radiology, Mayo Clinic, Rochester, Minnesota, USA
| | - Lilach O. Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
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Klomjit N, Zhu XY, Massat AE, Pawar AS, Conley S, Puranik AS, Ferguson CM, Kim SR, Tang H, Jordan K, Saadiq I, Lerman A, Grande JP, Textor SC, Lerman LO. Microvascular remodeling and altered angiogenic signaling in human kidneys distal to occlusive atherosclerotic renal artery stenosis. Nephrol Dial Transplant 2022; 37:1844-1856. [PMID: 35451482 PMCID: PMC9494086 DOI: 10.1093/ndt/gfac156] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Renal artery stenosis (RAS) is an important cause of chronic kidney disease and secondary hypertension. In animal models, renal ischemia leads to downregulation of growth-factor expression and loss of intrarenal microcirculation. However, little is known about the sequelae of large vessel occlusive disease on the microcirculation within human kidneys. METHOD This study included 5 patients who underwent nephrectomy due to renovascular occlusion, and 7 non-stenotic discarded donor kidneys (4 deceased donors). Micro-computed tomography was performed to assess microvascular spatial densities and tortuosity, an index of microvascular immaturity. Renal protein expression, gene expression, and histology were studied in-vitro using immunoblotting, polymerase-chain-reaction, and staining. RESULTS RAS demonstrated loss of medium-sized vessels (0.2-0.3mm) compared to donor kidneys (p = 0.037) and increased microvascular tortuosity. RAS kidneys had greater protein expression of angiopoietin-1, hypoxia-inducible factor (HIF)-1α, and thrombospondin (TSP)-1, but lower protein expression of vascular endothelial growth factor (VEGF) than donor kidneys. Renal fibrosis, loss of peritubular capillaries (PTC) and pericyte detachment were greater in RAS, yet they had more newly-formed PTC than donor kidneys. Therefore, our study quantified significant microvascular remodeling in the post-stenotic human kidney. RAS induced renal microvascular loss, vascular remodeling, and fibrosis. Despite downregulated VEGF, stenotic kidneys upregulated compensatory angiogenic pathways related to angiopoietin-1. CONCLUSIONS These observations underscore the nature of human RAS as a microvascular disease distal to main vessel stenosis, and support therapeutic strategies directly targeting the post-stenotic kidney microcirculation in patients with RAS.
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Affiliation(s)
- Nattawat Klomjit
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Division of Nephrology and Hypertension, University of Minnesota, Minneapolis, MN, USA
| | - Xiang-Yang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | - Aditya S Pawar
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Sabena Conley
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Amrutesh S Puranik
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | - Seo Rin Kim
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Hui Tang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Kyra Jordan
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Ishran Saadiq
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Amir Lerman
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN, USA
| | - Joseph P Grande
- Department of Laboratory Medicine and Pathology, Mayo Clinic, Rochester, USA
| | - Stephen C Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Exaggerated natriuresis after renal artery balloon angioplasty for flash pulmonary oedema. J Hypertens 2022; 40:1042-1049. [DOI: 10.1097/hjh.0000000000003128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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8
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Afarideh M, Jiang K, Ferguson CM, Woollard JR, Glockner JF, Lerman LO. Magnetization Transfer Imaging Predicts Porcine Kidney Recovery After Revascularization of Renal Artery Stenosis. Invest Radiol 2021; 56:86-93. [PMID: 33405430 PMCID: PMC7793546 DOI: 10.1097/rli.0000000000000711] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
MATERIALS AND METHODS Stenotic kidney (STK) and contralateral kidney magnetization transfer ratios (MTRs; Mt/M0) were measured at 3.0-T magnetic resonance imaging, at offset frequencies of 600 and 1000 Hz, before and 1 month post-PTRA in 7 RVD pigs. Stenotic kidney MTR was correlated to renal perfusion, renal blood flow (RBF), and glomerular filtration rate (GFR), determined using multidetector computed tomography and with ex vivo renal fibrosis (trichrome staining). Untreated RVD (n = 6) and normal pigs (n = 7) served as controls. RESULTS Renovascular disease induced hypertension and renal dysfunction. Blood pressure and renal perfusion were unchanged post-PTRA, but GFR and RBF increased. Baseline cortical STK-MTR predicted post-PTRA renal perfusion and RBF, and MTR changes associated inversely with changes in perfusion and normalized GFR. Stenotic kidney MTR at 600 Hz showed closer association with renal parameters, but both frequencies predicted post-PTRA cortical fibrosis. CONCLUSIONS Renal STK-MTR, particularly at 600 Hz offset, is sensitive to hemodynamic changes after PTRA in swine RVD and capable of noninvasively predicting post-PTRA kidney perfusion, RBF, and fibrosis. Therefore, STK-MTR may be a valuable tool to predict renal hemodynamic and functional recovery, as well as residual kidney fibrosis after revascularization in RVD.
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Affiliation(s)
| | - Kai Jiang
- From the Division of Nephrology and Hypertension
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Improved renal outcomes after revascularization of the stenotic renal artery in pigs by prior treatment with low-energy extracorporeal shockwave therapy. J Hypertens 2020; 37:2074-2082. [PMID: 31246892 DOI: 10.1097/hjh.0000000000002158] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Revascularization does not restore renal function in most patients with atherosclerotic renal artery stenosis (RAS), likely because of inflammation and fibrosis within the stenotic kidney. Low-energy shockwave therapy (LE-SWT) stimulates angiogenesis in the stenotic kidney, but its ability to improve renal function and structure after revascularization remains unexplored. We tested the hypothesis that a LE-SWT regimen before percutaneous transluminal renal angioplasty (PTRA) would enable PTRA to restore renal function in hypercholesterolemic pigs with RAS (HC+RAS), and that this would be associated with attenuation of renal inflammation and fibrosis. METHODS AND RESULTS Twenty-six pigs were studied after 16 weeks of HC+RAS, HC+RAS treated with PTRA with or without a preceding LE-SWT regimen (bi-weekly for 3 weeks), and controls. Single-kidney renal blood flow (RBF), glomerular filtration rate (GFR), and oxygenation were assessed in vivo using imaging 4 weeks after PTRA, and then inflammation and fibrosis ex vivo.Four weeks after successful PTRA, blood pressure fell similarly in both revascularized groups. Yet, stenotic-kidney GFR remained lower in HC+RAS and HC+RAS+PTRA (P < 0.01 vs. normal), but was improved in HC+RAS+PTRA+SW (P > 0.05 vs. normal). Furthermore, reduced inflammation, medullary fibrosis, and cortical hypoxia were only shown in swine stenotic kidneys pretreated with LE-SWT before PTRA 4 weeks later. CONCLUSION LE-SWT delivery before revascularization permitted PTRA to improve function and decrease cortical and medullary damage in the stenotic swine kidney. This study, therefore, supports the use of an adjunct SW pretreatment to enhance the success of PTRA in blunting loss of kidney function in experimental HC+RAS.
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A Boolean Model of Microvascular Rarefaction to Predict Treatment Outcomes in Renal Disease. Sci Rep 2020; 10:440. [PMID: 31949240 PMCID: PMC6965143 DOI: 10.1038/s41598-019-57386-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2019] [Accepted: 12/17/2019] [Indexed: 12/19/2022] Open
Abstract
Despite advances in renovascular disease (RVD) research, gaps remain between experimental and clinical outcomes, translation of results, and the understanding of pathophysiological mechanisms. A predictive tool to indicate support (or lack of) for biological findings may aid clinical translation of therapies. We created a Boolean model of RVD and hypothesized that it would predict outcomes observed in our previous studies using a translational swine model of RVD. Our studies have focused on developing treatments to halt renal microvascular (MV) rarefaction in RVD, a major feature of renal injury. A network topology of 20 factors involved in renal MV rarefaction that allowed simulation of 5 previously tested treatments was created. Each factor was assigned a function based upon its interactions with other variables and assumed to be “on” or “off”. Simulations of interventions were performed until outcomes reached a steady state and analyzed to determine pathological processes that were activated, inactivated, or unchanged vs. RVD with no intervention. Boolean simulations mimicked the results of our previous studies, confirming the importance of MV integrity on treatment outcomes in RVD. Furthermore, our study supports the potential application of a mathematical tool to predict therapeutic feasibility, which may guide the design of future studies for RVD.
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Gutsol AA, Blanco P, Samokhina SI, Afanasiev SA, Kennedy CRJ, Popov SV, Burns KD. A novel method for comparison of arterial remodeling in hypertension: Quantification of arterial trees and recognition of remodeling patterns on histological sections. PLoS One 2019; 14:e0216734. [PMID: 31112562 PMCID: PMC6529011 DOI: 10.1371/journal.pone.0216734] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/26/2019] [Indexed: 01/01/2023] Open
Abstract
Remodeling of spatially heterogeneous arterial trees is routinely quantified on tissue sections by averaging linear dimensions, with lack of comparison between different organs and models. The impact of experimental models or hypertension treatment modalities on organ-specific vascular remodeling remains undefined. A wide variety of arterial remodeling types has been demonstrated for hypertensive models, which include differences across organs. The purpose of this study was to reassess methods for measurement of arterial remodeling and to establish a morphometric algorithm for standard and comparable quantification of vascular remodeling in hypertension in different vascular beds. We performed a novel and comprehensive morphometric analysis of terminal arteries in the brain, heart, lung, liver, kidney, spleen, stomach, intestine, skin, skeletal muscle, and adrenal glands of control and Goldblatt hypertensive rats on routinely processed tissue sections. Mean dimensions were highly variable but grouping them into sequential 5 μm intervals permitted creation of reliable linear regression equations and complex profiles. Averaged arterial dimensions demonstrated seven remodeling patterns that were distinct from conventional inward-outward and hypertrophic-eutrophic definitions. Numerical modeling predicted at least nineteen variants of arterial spatial conformations. Recognition of remodeling variants was not possible using averaged dimensions, their ratios, or the remodeling and growth indices. To distinguish remodeling patterns, a three-dimensional modeling was established and tested. The proposed algorithm permits quantitative analysis of arterial remodeling in different organs and may be applicable for comparative studies between animal hypertensive models and human hypertension. Arterial wall tapering is the most important factor to consider in arterial morphometry, while perfusion fixation with vessel relaxation is not necessary. Terminal arteries in organs undergo the same remodeling pattern in Goldblatt rats, except for organs with hemodynamics affected by the arterial clip. The existing remodeling nomenclature should be replaced by a numerical classification applicable to any type of arterial remodeling.
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Affiliation(s)
- Alex A. Gutsol
- Kidney Research Centre, Ottawa Hospital Research Institute, ON, Canada
| | - Paula Blanco
- Department of Pathology and Laboratory Medicine, University of Ottawa, ON, Canada
| | | | | | | | | | - Kevin D. Burns
- Kidney Research Centre, Ottawa Hospital Research Institute, ON, Canada
- Division of Nephrology, Department of Medicine, University of Ottawa, ON, Canada
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Nifedipine Modulates Renal Lipogenesis via the AMPK-SREBP Transcriptional Pathway. Int J Mol Sci 2019; 20:ijms20071570. [PMID: 30934807 PMCID: PMC6480582 DOI: 10.3390/ijms20071570] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Revised: 03/16/2019] [Accepted: 03/27/2019] [Indexed: 12/13/2022] Open
Abstract
Lipid accumulation in renal cells has been implicated in the pathogenesis of obesity-related kidney disease, and lipotoxicity in the kidney can be a surrogate marker for renal failure or renal fibrosis. Fatty acid oxidation provides energy to renal tubular cells. Ca2+ is required for mitochondrial ATP production and to decrease reactive oxygen species (ROS). However, how nifedipine (a calcium channel blocker) affects lipogenesis is unknown. We utilized rat NRK52E cells pre-treated with varying concentrations of nifedipine to examine the activity of lipogenesis enzymes and lipotoxicity. A positive control exposed to oleic acid was used for comparison. Nifedipine was found to activate acetyl Coenzyme A (CoA) synthetase, acetyl CoA carboxylase, long chain fatty acyl CoA elongase, ATP-citrate lyase, and 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase, suggesting elevated production of cholesterol and phospholipids. Nifedipine exposure induced a vast accumulation of cytosolic free fatty acids (FFA) and stimulated the production of reactive oxygen species, upregulated CD36 and KIM-1 (kidney injury molecule-1) expression, inhibited p-AMPK activity, and triggered the expression of SREBP-1/2 and lipin-1, underscoring the potential of nifedipine to induce lipotoxicity with renal damage. To our knowledge, this is the first report demonstrating nifedipine-induced lipid accumulation in the kidney.
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13
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Kerforne T, Favreau F, Khalifeh T, Maiga S, Allain G, Thierry A, Dierick M, Baulier E, Steichen C, Hauet T. Hypercholesterolemia-induced increase in plasma oxidized LDL abrogated pro angiogenic response in kidney grafts. J Transl Med 2019; 17:26. [PMID: 30642356 PMCID: PMC6332834 DOI: 10.1186/s12967-018-1764-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 12/31/2018] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Renal transplantation is increasingly associated with the presence of comorbidity factors such as dyslipidemia which could influence the graft outcome. We hypothesized that hypercholesterolemia could affect vascular repair processes and promote post-transplant renal vascular remodeling through the over-expression of the anti-angiogenic thrombospondin-1 interacting with vascular endothelial growth factor-A levels. METHODS We tested this hypothesis in vitro, in vivo and in a human cohort using (1) endothelial cells; (2) kidney auto-transplanted pig subjected (n = 5) or not (n = 6) to a diet enriched in cholesterol and (3) a renal transplanted patient cohort (16 patients). RESULTS Cells exposed to oxidized LDL showed reduced proliferation and an increased expression of thrombospondin-1. In pigs, 3 months after transplantation of kidney grafts, we observed a deregulation of the hypoxia inducible factor 1a-vascular endothelial growth factor-A axis induced in cholesterol-enriched diet animals concomitant with an overexpression of thrombospondin-1 and a decrease in cortical microvessel density promoting vascular remodeling. In patients, hypercholesterolemia was associated with decreased vascular endothelial growth factor-A plasma levels during early follow up after renal transplantation and increased chronic graft dysfunction. CONCLUSIONS These results support a potential mechanism through which a high fat-diet impedes vascular repair in kidney graft and suggest the value of controlling cholesterolemia in recipient even at the early stage of renal transplantation.
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Affiliation(s)
- Thomas Kerforne
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Service d’Anesthésie-Réanimation, CHU de Poitiers, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
| | - Frédéric Favreau
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine, EA 6309 “Maintenance Myélinique et Neuropathies Périphériques», Université de Limoges, 87000 Limoges, France
- Laboratoire de Biochimie et Génétique Moléculaire, CHU de Limoges, 87000 Limoges, France
| | - Tackwa Khalifeh
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Service Medico-Chirurgical de Pediatrie, CHU de Poitiers, 86000 Poitiers, France
| | - Souleymane Maiga
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
| | - Geraldine Allain
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
- Service de Chirurgie Cardio-Thoracique, CHU de Poitiers, 86000 Poitiers, France
| | - Antoine Thierry
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
- Service de Néphrologie et Transplantation, CHU de Poitiers, 86000 Poitiers, France
| | - Manuel Dierick
- UGCT-Department of Physics and Astronomy, Faculty of Sciences, Ghent University, Proeftuinstraat 86, 9000 Ghent, Belgium
| | - Edouard Baulier
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
- Service de Biochimie, CHU de Poitiers, Poitiers, 86000 France
| | - Clara Steichen
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
| | - Thierry Hauet
- INSERM U1082 IRTOMIT, 2 rue de la Milétrie, CS90577, 86000 Poitiers, France
- Faculté de Médecine et de Pharmacie, Université de Poitiers, 86000 Poitiers, France
- Service de Biochimie, CHU de Poitiers, Poitiers, 86000 France
- IBiSA ‘Plate-Forme MOdélisation Préclinique-Innovations Chirurgicale et Technologique (MOPICT)’, Domaine Expérimental du Magneraud, 17700 Surgères, France
- FHU SUPORT ‘SUrvival oPtimization in ORgan Transplantation’, 86000 Poitiers, France
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Eirin A, Hedayat AF, Ferguson CM, Textor SC, Lerman A, Lerman LO. Mitoprotection preserves the renal vasculature in porcine metabolic syndrome. Exp Physiol 2018; 103:1020-1029. [PMID: 29714040 DOI: 10.1113/ep086988] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 04/20/2018] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? We hypothesized that chronic mitoprotection would decrease renal vascular remodelling and dysfunction in swine metabolic syndrome. What is the main finding and its importance? This study shows that experimental metabolic syndrome exerts renal microvascular and endothelial cell mitochondrial injury, which were attenuated by mitoprotection, underscoring the contribution of mitochondrial injury to the pathogenesis of metabolic syndrome-induced vascular damage. ABSTRACT The metabolic syndrome (MetS) induces intrarenal microvascular disease, which may involve mitochondrial injury. The mitochondrial cardiolipin-targeting peptide elamipretide (ELAM) improves the microcirculation in post-stenotic kidneys, but its ability to attenuate MetS-induced renal vascular damage is unknown. We hypothesized that chronic treatment with ELAM would decrease renal vascular remodelling and function in swine MetS. Pigs were studied after 16 weeks of diet-induced MetS, MetS treated for the last 4 weeks with daily injections of ELAM (0.1 mg kg-1 ), and lean control (Lean) animals (n = 6 each). Single-kidney regional perfusion, blood flow and glomerular filtration rate were measured with multi-detector computed tomography (CT). Peritubular capillary (PTC) endothelial cell (EC) mitochondrial density and cardiolipin content were assessed in situ, as were PTC-EC apoptosis and oxidative stress. The spatial density of PTCs (Haematoxylin and Eosin staining) and renal microvessels (micro-CT), and renal artery endothelial function (organ bath) were characterized. Regional perfusion and serum creatinine were preserved in MetS pigs, but renal blood flow and glomerular filtration rate were higher compared with Lean. Mitochondrial density and cardiolipin content were diminished in MetS PTC-ECs, but improved in ELAM-treated pigs, as did PTC density. Elamipretide also attenuated PTC-EC oxidative stress and apoptosis. Furthermore, ELAM improved renal microvascular density, decreased microvascular remodelling and restored endothelial nitric oxide expression and endothelium-dependent relaxation of renal artery segments. In conclusion, MetS-induced mitochondrial alterations might contribute to renal PTC and microvascular loss and might impair renal artery endothelial function in pigs. Mitoprotection with ELAM preserved a hierarchy of renal vessels, underscoring its potential to ameliorate renal vascular injury in MetS.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Ahmad F Hedayat
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | - Stephen C Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | - Amir Lerman
- Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA.,Cardiovascular Diseases, Mayo Clinic, Rochester, MN, USA
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15
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Sun D, Chen Z, Eirin A, Zhu XY, Lerman A, Textor SC, Lerman LO. Hypercholesterolemia Impairs Nonstenotic Kidney Outcomes After Reversal of Experimental Renovascular Hypertension. Am J Hypertens 2016; 29:853-9. [PMID: 26739189 DOI: 10.1093/ajh/hpv222] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 12/17/2015] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Revascularization of a stenotic renal artery improves kidney function only in select patients with renovascular hypertension (HT) secondary to atherosclerosis. However, the effects of reversal of renovascular HT (RRHT) on the nonstenotic kidney are unclear. We hypothesized that concurrent hypercholesterolemia (HC) attenuates nonstenotic kidney recovery. METHODS Female domestic pigs were randomized as Normal, renovascular HT, HT+RRHT, HTC (renovascular HT and HC), and HTC+RHT (n = 7 each). RRHT or sham was performed after 6 weeks of HT. Nonstenotic renal blood flow, glomerular filtration rate, and injurious pathways were studied 4 weeks later. RESULTS Mean arterial pressure increased similarly in HT and HTC and decreased after RRHT. Oxidative stress increased in HT and HTC kidneys, and decreased in HT+RRHT, but remained elevated in HTC+RRHT. Renal interstitial fibrosis, glomerulosclerosis, and tubular injury were all attenuated in HT+RRHT, but not HTC+RRHT. Endothelin-1 signaling and PGF2α isoprostane levels were elevated in both HTC and HTC+RRHT pigs. CONCLUSIONS RRHT reverses nonstenotic kidney injury in experimental renovascular HT, but concurrent HC blunts regression of kidney injury, possibly due to predominant vasoconstrictors and oxidative stress. These findings reinforce the contribution of the nonstenotic kidney and of prevailing cardiovascular risk factors to irreversibility of kidney dysfunction after revascularization.
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Affiliation(s)
- Dong Sun
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; The Department of Nephrology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, China
| | - Zhi Chen
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Alfonso Eirin
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiang-Yang Zhu
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Amir Lerman
- The Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota, USA
| | - Stephen C Textor
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Lilach O Lerman
- The Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA; The Division of Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota, USA.
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16
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Zhang X, Krier JD, Amador Carrascal C, Greenleaf JF, Ebrahimi B, Hedayat AF, Textor SC, Lerman A, Lerman LO. Low-Energy Shockwave Therapy Improves Ischemic Kidney Microcirculation. J Am Soc Nephrol 2016; 27:3715-3724. [PMID: 27297945 DOI: 10.1681/asn.2015060704] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 04/05/2016] [Indexed: 12/12/2022] Open
Abstract
Microvascular rarefaction distal to renal artery stenosis is linked to renal dysfunction and poor outcomes. Low-energy shockwave therapy stimulates angiogenesis, but the effect on the kidney microvasculature is unknown. We hypothesized that low-energy shockwave therapy would restore the microcirculation and alleviate renal dysfunction in renovascular disease. Normal pigs and pigs subjected to 3 weeks of renal artery stenosis were treated with six sessions of low-energy shockwave (biweekly for 3 consecutive weeks) or left untreated. We assessed BP, urinary protein, stenotic renal blood flow, GFR, microvascular structure, and oxygenation in vivo 4 weeks after completion of treatment, and then, we assessed expression of angiogenic factors and mechanotransducers (focal adhesion kinase and β1-integrin) ex vivo A 3-week low-energy shockwave regimen attenuated renovascular hypertension, normalized stenotic kidney microvascular density and oxygenation, stabilized function, and alleviated fibrosis in pigs subjected to renal artery stenosis. These effects associated with elevated renal expression of angiogenic factors and mechanotransducers, particularly in proximal tubular cells. In additional pigs with prolonged (6 weeks) renal artery stenosis, shockwave therapy also decreased BP and improved GFR, microvascular density, and oxygenation in the stenotic kidney. This shockwave regimen did not cause detectable kidney injury in normal pigs. In conclusion, low-energy shockwave therapy improves stenotic kidney function, likely in part by mechanotransduction-mediated expression of angiogenic factors in proximal tubular cells, and it may ameliorate renovascular hypertension. Low-energy shockwave therapy may serve as a novel noninvasive intervention in the management of renovascular disease.
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Affiliation(s)
- Xin Zhang
- Division of Nephrology and Hypertension and
| | | | | | | | | | | | | | - Amir Lerman
- Cardiology, Mayo Clinic, Rochester, Minnesota
| | - Lilach O Lerman
- Division of Nephrology and Hypertension and .,Cardiology, Mayo Clinic, Rochester, Minnesota
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17
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Sun D, Eirin A, Ebrahimi B, Textor SC, Lerman A, Lerman LO. Early atherosclerosis aggravates renal microvascular loss and fibrosis in swine renal artery stenosis. ACTA ACUST UNITED AC 2016; 10:325-35. [PMID: 26879682 DOI: 10.1016/j.jash.2016.01.019] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2015] [Revised: 01/11/2016] [Accepted: 01/14/2016] [Indexed: 01/04/2023]
Abstract
Renal function in patients with atherosclerosis and renal artery stenosis (ARAS) deteriorates more frequently than in nonatherosclerotic RAS. We hypothesized that ARAS aggravates stenotic-kidney micro vascular loss compared to RAS. Domestic pigs were randomized to normal, RAS, and ARAS (RAS fed a high-cholesterol diet) groups (n = 7 each). Ten weeks later stenotic-kidney oxygenation, renal blood flow, and glomerular filtration rate (GFR) were evaluated in vivo, and micro vascular density by micro-computed tomography. Blood pressure in both RAS and ARAS was elevated; and stenotic-kidney renal blood flow and GFR similarly decreased. RAS decreased the density of small-size cortical microvessels (<200 μm), whereas ARAS extended the decrease to medium-sized microvessels (200-300 μm). Cortical hypoxia and interstitial fibrosis increased in both RAS and ARAS but correlated inversely with micro vascular density only in RAS. Atherosclerosis aggravates loss of stenotic-kidney microvessels, yet additional determinants likely contribute to cortical hypoxia and fibrosis in swine ARAS.
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Affiliation(s)
- Dong Sun
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA; Department of Nephrology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, China
| | - Alfonso Eirin
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Behzad Ebrahimi
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Stephen C Textor
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA
| | - Amir Lerman
- Department of Cardiovascular Disease, Mayo Clinic, Rochester, MN, USA
| | - Lilach O Lerman
- Division of Nephrology and Hypertension, Department of Medicine, Mayo Clinic, Rochester, MN, USA; Department of Cardiovascular Disease, Mayo Clinic, Rochester, MN, USA.
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18
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Park S, Kim CS, Min J, Lee SH, Jung YS. A high-fat diet increases oxidative renal injury and protein glycation in D-galactose-induced aging rats and its prevention by Korea red ginseng. J Nutr Sci Vitaminol (Tokyo) 2015; 60:159-66. [PMID: 25078371 DOI: 10.3177/jnsv.60.159] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Declining renal function is commonly observed with age. Obesity induced by a high-fat diet (HFD) may reduce renal function. Korean red ginseng (KRG) has been reported to ameliorate oxidative tissue injury and have an anti-aging effect. This study was designed to investigate whether HFD would accelerate the D-galactose-induced aging process in the rat kidney and to examine the preventive effect of KRG on HFD and D-galactose-induced aging-related renal injury. When rats with D-galactose-induced aging were fed an HFD for 9 wk, enhanced oxidative DNA damage, renal cell apoptosis, protein glycation, and extracellular high mobility group box 1 protein (HMGB1), a signal of tissue damage, were observed in renal glomerular cells and tubular epithelial cells. However, treatment of rats with HFD- plus D-galactose-induced aging with KRG restored all of these renal changes. Our data suggested that a long-term HFD may enhance D-galactose-induced oxidative renal injury in rats and that this age-related renal injury could be suppressed by KRG through the repression of oxidative injury.
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Affiliation(s)
- Sok Park
- Division of Sports Industry & Science, Mokwon University
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19
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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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20
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Angiotensin-(1-7)-induced renal vasodilation is reduced in human kidneys with renal artery stenosis. J Hypertens 2014; 32:2428-32; discussion 2432. [DOI: 10.1097/hjh.0000000000000351] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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21
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Sun D, Eirin A, Zhu XY, Zhang X, Crane JA, Woollard JR, Lerman A, Lerman LO. Experimental coronary artery stenosis accelerates kidney damage in renovascular hypertensive swine. Kidney Int 2014; 87:719-27. [PMID: 25337776 PMCID: PMC4382395 DOI: 10.1038/ki.2014.343] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 07/29/2014] [Accepted: 08/14/2014] [Indexed: 01/13/2023]
Abstract
The impact of coronary artery stenosis (CAS) to renal injury is unknown. Here we tested whether the existence of CAS, regardless of concurrent atherosclerosis, would induce kidney injury and magnify its susceptibility to damage from co-existing hypertension (HT). Pigs (7 each) were assigned to Sham, left-circumflex CAS, renovascular HT, and CAS plus HT groups. Cardiac and non-stenotic kidney functions, circulating and renal inflammatory and oxidative markers, and renal and microvascular remodeling, were assessed 10 weeks later. Myocardial perfusion declined distal to CAS. Systemic levels of PGF2-α isoprostane, a marker of oxidative stress, increased in CAS and CAS plus HT, while single-kidney blood flow responses to acetylcholine were significantly blunted only in CAS plus HT compared to sham, HT, and CAS, indicating renovascular endothelial dysfunction. Tissue expression of inflammatory and oxidative markers were elevated in the CAS pig kidney, and further magnified in CAS plus HT, whereas angiogenic factor expression was decreased. Bendavia, a mitochondria-targeted peptide, decreased oxidative stress and improved renal function and structure in CAS. Furthermore, CAS and HT synergistically amplified glomerulosclerosis and renal fibrosis. Thus, mild myocardial ischemia, independent of systemic atherosclerosis, induced renal injury, possibly mediated by increased oxidative stress. Superimposed HT aggravates renal inflammation and endothelial dysfunction caused by CAS, and synergistically promotes kidney fibrosis, providing impetus to preserve cardiac integrity in order to protect the kidney.
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Affiliation(s)
- Dong Sun
- 1] Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA [2] Department of Nephrology, The Affiliated Hospital of Xuzhou Medical College, Xuzhou, China
| | - Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Xiang-Yang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - John A Crane
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - John R Woollard
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | - Amir Lerman
- Division Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota, USA
| | - Lilach O Lerman
- 1] Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA [2] Division Cardiovascular Disease, Mayo Clinic, Rochester, Minnesota, USA
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22
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Chatauret N, Favreau F, Giraud S, Thierry A, Rossard L, Le Pape S, Lerman LO, Hauet T. Diet-induced increase in plasma oxidized LDL promotes early fibrosis in a renal porcine auto-transplantation model. J Transl Med 2014; 12:76. [PMID: 24655356 PMCID: PMC3994364 DOI: 10.1186/1479-5876-12-76] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2013] [Accepted: 03/12/2014] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND In kidney transplantation, the prevalence of hypercholesterolemia as a co-morbidity factor known to affect graft function, is rising due to the increased number of older donors in response to organ shortage as well as to the hyperlipidemic effects of immunosuppressors in recipient. This study aimed to characterize the effects of hypercholesterolemia on renal graft outcome, investigating the role of oxidized low-density lipoprotein (OxLDL). METHODS In vivo, we used a porcine preclinical model of renal auto-transplantation modulated by two experimental diets: a normal (n = 6) or a hyperlipidemic diet (n = 5) maintained during the 3 month follow-up after the surgical procedure. Kidney function and OxLDL levels were monitored as well as fibrosis, LOX-1 and TGF beta signaling pathways. In vitro, we used human artery endothelial cells subjected to OxLDL to investigate the TGF beta profibrotic pathway and the role of the scavenger receptor LOX-1. RESULTS Hyperlipidemic diet-induced increase in plasma OxLDL levels at the time of surgery correlated with an increase in proteinuria 3 months after transplantation, associated with an early graft fibrosis combined with an activation of renal TGF beta signaling. These data suggest a direct involvement of OxLDL in the hyperlipidemic diet-induced activation of the pro-fibrotic TGF beta pathway which seems to be activated by LOX-1 signaling. These results were supported by studies with endothelial cells incubated in culture medium containing OxLDL promoting TGF beta expression inhibited by LOX-1 antibody. CONCLUSIONS These results implicate OxLDL in the hyperlipidemic diet-promoted fibrosis in transplanted kidneys, suggesting LOX-1 as a potential therapeutic target and reinforce the need to control cholesterol levels in kidney transplant recipients.
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Affiliation(s)
| | | | | | | | | | | | | | - Thierry Hauet
- INSERM, U1082, Ischémie-reperfusion en transplantation rénale, Université de Poitiers, Faculté de Médecine et de Pharmacie, Poitiers 86000, France.
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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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24
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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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25
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Ebrahimi B, Eirin A, Li Z, Zhu XY, Zhang X, Lerman A, Textor SC, Lerman LO. Mesenchymal stem cells improve medullary inflammation and fibrosis after revascularization of swine atherosclerotic renal artery stenosis. PLoS One 2013; 8:e67474. [PMID: 23844014 PMCID: PMC3701050 DOI: 10.1371/journal.pone.0067474] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2012] [Accepted: 05/17/2013] [Indexed: 12/16/2022] Open
Abstract
Atherosclerotic renal artery stenosis (ARAS) raises blood pressure and can reduce kidney function. Revascularization of the stenotic renal artery alone does not restore renal medullary structure and function. This study tested the hypothesis that addition of mesenchymal stem cells (MSC) to percutaneous transluminal renal angioplasty (PTRA) can restore stenotic-kidney medullary tubular transport function and attenuate its remodeling. Twenty-seven swine were divided into three ARAS (high-cholesterol diet and renal artery stenosis) and a normal control group. Six weeks after ARAS induction, two groups were treated with PTRA alone or PTRA supplemented with adipose-tissue-derived MSC (10×106 cells intra-renal). Multi-detector computed tomography and blood-oxygenation-level-dependent (BOLD) MRI studies were performed 4 weeks later to assess kidney hemodynamics and function, and tissue collected a few days later for histology and micro-CT imaging. PTRA effectively decreased blood pressure, yet medullary vascular density remained low. Addition of MSC improved medullary vascularization in ARAS+PTRA+MSC and increased angiogenic signaling, including protein expression of vascular endothelial growth-factor, its receptor (FLK-1), and hypoxia-inducible factor-1α. ARAS+PTRA+MSC also showed attenuated inflammation, although oxidative-stress remained elevated. BOLD-MRI indicated that MSC normalized oxygen-dependent tubular response to furosemide (-4.3±0.9, −0.1±0.4, −1.6±0.9 and −3.6±1.0 s−1 in Normal, ARAS, ARAS+PTRA and ARAS+PTRA+MSC, respectively, p<0.05), which correlated with a decrease in medullary tubular injury score (R2 = 0.33, p = 0.02). Therefore, adjunctive MSC delivery in addition to PTRA reduces inflammation, fibrogenesis and vascular remodeling, and restores oxygen-dependent tubular function in the stenotic-kidney medulla, although additional interventions might be required to reduce oxidative-stress. This study supports development of cell-based strategies for renal protection in ARAS.
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Affiliation(s)
- Behzad Ebrahimi
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zilun Li
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- Division of Vascular Surgery, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, China
| | - Xiang-Yang Zhu
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Amir Lerman
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Stephen C. Textor
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Lilach O. Lerman
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
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Zhang X, Li ZL, Woollard JR, Eirin A, Ebrahimi B, Crane JA, Zhu XY, Pawar AS, Krier JD, Jordan KL, Tang H, Textor SC, Lerman A, Lerman LO. Obesity-metabolic derangement preserves hemodynamics but promotes intrarenal adiposity and macrophage infiltration in swine renovascular disease. Am J Physiol Renal Physiol 2013; 305:F265-76. [PMID: 23657852 DOI: 10.1152/ajprenal.00043.2013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Obesity-metabolic disorders (ObM) often accompany renal artery stenosis (RAS). We hypothesized that the coexistence of ObM and RAS magnifies inflammation and microvascular remodeling in the stenotic kidney (STK) and aggravates renal scarring. Twenty-eight obesity-prone Ossabaw pigs were studied after 16 wk of a high-fat/high-fructose diet or standard chow including ObM-sham, ObM-RAS, Lean-RAS, or Lean-sham (normal control) groups. Single-kidney renal blood flow (RBF) and glomerular filtration rate (GFR) were assessed by multidetector computed tomography (CT), renal oxygenation and tubular transport capability by blood-oxygen-level-dependent MRI, and microcirculation by micro-CT for vessel density, and Western blotting for protein expressions of angiogenic factors (VEGF/FLK-1). Renal vein and inferior vena cava levels of inflammatory cytokines were measured to evaluate systemic and kidney inflammation. Macrophage (MØ) infiltration and subpopulations, fat deposition in the kidney, and inflammation in perirenal and abdominal fat were also examined. GFR and RBF were decreased in Lean-STK but relatively preserved in ObM-STK. However, ObM-STK showed impaired tubular transport function, suppressed microcirculation, and stimulated glomerulosclerosis. ObM diet interacted with RAS to blunt angiogenesis in the STK, facilitated the release of inflammatory cytokines, and led to greater oxidative stress than Lean-STK. The ObM diet also induced fat deposition in the kidney and infiltration of proinflammatory M1-MØ, as also in perirenal and abdominal fat. Coexistence of ObM and RAS amplifies renal inflammation, aggravates microvascular remodeling, and accelerates glomerulosclerosis. Increased adiposity and MØ-accentuated inflammation induced by an ObM diet may contribute to structural injury in the post-STK kidney.
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Affiliation(s)
- Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
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Zhang X, Eirin A, Li ZL, Crane JA, Krier JD, Ebrahimi B, Pawar AS, Zhu XY, Tang H, Jordan KL, Lerman A, Textor SC, Lerman LO. Angiotensin receptor blockade has protective effects on the poststenotic porcine kidney. Kidney Int 2013; 84:767-75. [PMID: 23615504 PMCID: PMC3732527 DOI: 10.1038/ki.2013.144] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2012] [Revised: 01/14/2013] [Accepted: 02/14/2013] [Indexed: 12/19/2022]
Abstract
Angiotensin converting enzyme inhibitors (ACEI)/ angiotensin-II receptor blockers (ARBs) may induce an acute decrease of glomerular filtration rate (GFR) in the stenotic kidney in renal artery stenosis, but most patients tolerate these drugs well. We hypothesized that ACEI/ARBs stabilize stenotic kidney function during prolonged treatment by conferring protective effects. We tested this in control domestic pigs and pigs with renal artery stenosis untreated or treated with valsartan, or triple therapy (7 pigs in each group) for 4 weeks starting 6 weeks after stenosis induction. Renal function, oxygenation, tubular function, and microcirculation were assessed by multi-detector computed tomography (CT), blood-oxygen-level-dependent magnetic-resonance imaging, and micro-CT. Valsartan and triple therapy decreased blood pressure similarly, however, valsartan did not change the GFR of the stenotic kidney compared to renal artery stenosis and was similar to triple therapy. Both valsartan and triple therapy stimulated microvascular density, and improved tubular function. Valsartan also caused a greater increase of angiogenic factors and a decrease in oxidative stress, which were related to higher cortical perfusion and tubular response than triple therapy. Thus, valsartan did not decrease stenotic kidney GFR, but improved cortical perfusion and microcirculation. These beneficial effects may partly offset the hemodynamic GFR reduction in renal artery stenosis and preserve kidney function.
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Affiliation(s)
- Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
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Eirin A, Zhu XY, Li Z, Ebrahimi B, Zhang X, Tang H, Korsmo MJ, Chade AR, Grande JP, Ward CJ, Simari RD, Lerman A, Textor SC, Lerman LO. Endothelial outgrowth cells shift macrophage phenotype and improve kidney viability in swine renal artery stenosis. Arterioscler Thromb Vasc Biol 2013; 33:1006-13. [PMID: 23430615 DOI: 10.1161/atvbaha.113.301164] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
OBJECTIVE Endothelial outgrowth cells (EOC) decrease inflammation and improve endothelial repair. Inflammation aggravates kidney injury in renal artery stenosis (RAS), and may account for its persistence upon revascularization. We hypothesized that EOC would decrease inflammatory (M1) macrophages and improve renal recovery in RAS. APPROACH AND RESULTS Pigs with 10 weeks of RAS were studied 4 weeks after percutaneous transluminal renal angioplasty (PTRA+stenting) or sham, with or without adjunct intrarenal delivery of autologous EOC (10×10(6)), and compared with similarly treated normal controls (n=7 each). Single-kidney function, microvascular and tissue remodeling, inflammation, oxidative stress, and fibrosis were evaluated. Four weeks after PTRA, EOC were engrafted in injected RAS-kidneys. Stenotic-kidney glomerular filtration rate was restored in RAS+EOC, RAS+PTRA, and RAS+PTRA+EOC pigs, whereas stenotic-kidney blood flow and angiogenesis were improved and fibrosis attenuated only in EOC-treated pigs. Furthermore, EOC increased cell proliferation and decreased the ratio of M1 (inflammatory)/M2 (reparative) macrophages, as well as circulating levels and stenotic-kidney release of inflammatory cytokines. Cultured-EOC released microvesicles in vitro and induced phenotypic switch (M1-to-M2) in cultured monocytes, which was inhibited by vascular endothelial growth factor blockade. Finally, a single intrarenal injection of rh-vascular endothelial growth factor (0.05 μg/kg) in 7 additional RAS pigs also restored M1/M2 ratio 4 weeks later. CONCLUSIONS Intrarenal infusion of EOC after PTRA induced a vascular endothelial growth factor-mediated attenuation in macrophages inflammatory phenotype, preserved microvascular architecture and function, and decreased inflammation and fibrosis in the stenotic kidney, suggesting a novel mechanism and therapeutic potential for adjunctive EOC delivery in experimental RAS to improve PTRA outcomes.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
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Eirin A, Ebrahimi B, Zhang X, Zhu XY, Tang H, Crane JA, Lerman A, Textor SC, Lerman LO. Changes in glomerular filtration rate after renal revascularization correlate with microvascular hemodynamics and inflammation in Swine renal artery stenosis. Circ Cardiovasc Interv 2012; 5:720-8. [PMID: 23048054 DOI: 10.1161/circinterventions.112.972596] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
BACKGROUND The selection of patients with renal artery stenosis (RAS) likely to improve glomerular filtration rate (GFR) after percutaneous transluminal renal angioplasty is difficult. We examined basal hemodynamic and inflammatory factors linked to improved stenotic kidney (STK) function after percutaneous transluminal renal angioplasty in swine RAS. METHODS AND RESULTS Fifteen pigs after 6 weeks of hemodynamically significant RAS were studied before and 4 weeks after technically successful percutaneous transluminal renal angioplasty+stenting. STK and contralateral kidney hemodynamics and function were evaluated by multidetector computed-tomography before and after acetylcholine challenge. Single-kidney deoxyhemoglobin (R2*, reciprocal to blood relaxation) and energy-dependent tubular function were assessed using blood-oxygen-level-dependent magnetic resonance imaging before and after furosemide. Baseline renal vein and inferior vena cava levels of inflammatory markers were measured and their gradient and net release calculated. Baseline parameters were compared with normal (n=7) and sham-RAS (n=7) pigs and correlated with the change in STK-GFR after revascularization (ΔGFR). Four weeks after percutaneous transluminal, renal angioplasty blood pressure was normalized in all animals, but STK-GFR improved in 10 of 15 (ΔGFR =+22.0±8.5 mL/min). ΔGFR correlated inversely with basal STK-GFR, renal release of inflammatory markers, and medullary R2* response to furosemide, but directly with GFR response to acetylcholine. Basal contralateral kidney GFR correlated directly with ΔGFR. CONCLUSIONS Low basal STK-GFR with preserved response to acetylcholine may predict benefit from revascularization in RAS, whereas renal inflammation and robust STK-R2* responses to furosemide (possibly reflecting avid tubular oxygen consumption) are associated with less favorable outcomes. These tools may be useful for identification of patients likely to improve renal function after revascularization.
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Affiliation(s)
- Alfonso Eirin
- Divisions of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA
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Eirin A, Zhu XY, Krier JD, Tang H, Jordan KL, Grande JP, Lerman A, Textor SC, Lerman LO. Adipose tissue-derived mesenchymal stem cells improve revascularization outcomes to restore renal function in swine atherosclerotic renal artery stenosis. Stem Cells 2012; 30:1030-41. [PMID: 22290832 DOI: 10.1002/stem.1047] [Citation(s) in RCA: 180] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Reno-protective strategies are needed to improve renal outcomes in patients with atherosclerotic renal artery stenosis (ARAS). Adipose tissue-derived mesenchymal stem cells (MSCs) can promote renal regeneration, but their potential for attenuating cellular injury and restoring kidney repair in ARAS has not been explored. We hypothesized that replenishment of MSC as an adjunct to percutaneous transluminal renal angioplasty (PTRA) would restore renal cellular integrity and improve renal function in ARAS pigs. Four groups of pigs (n = 7 each) were studied after 16 weeks of ARAS, ARAS 4 weeks after PTRA and stenting with or without adjunct intrarenal delivery of MSC (10 × 10(6) cells), and controls. Stenotic kidney blood flow (renal blood flow [RBF]) and glomerular filtration rate (GFR) were measured using multidetector computer tomography (CT). Renal microvascular architecture (micro-CT), fibrosis, inflammation, and oxidative stress were evaluated ex vivo. Four weeks after successful PTRA, mean arterial pressure fell to a similar level in all revascularized groups. Stenotic kidney GFR and RBF remained decreased in ARAS (p = .01 and p = .02) and ARAS + PTRA (p = .02 and p = .03) compared with normal but rose to normal levels in ARAS + PTRA + MSC (p = .34 and p = .46 vs. normal). Interstitial fibrosis, inflammation, microvascular rarefaction, and oxidative stress were attenuated only in PTRA + MSC-treated pigs. A single intrarenal delivery of MSC in conjunction with renal revascularization restored renal hemodynamics and function and decreased inflammation, apoptosis, oxidative stress, microvascular loss, and fibrosis. This study suggests a unique and novel therapeutic potential for MSC in restoring renal function when combined with PTRA in chronic experimental renovascular disease.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota 55905, USA
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Eirin A, Gloviczki ML, Tang H, Gössl M, Jordan KL, Woollard JR, Lerman A, Grande JP, Textor SC, Lerman LO. Inflammatory and injury signals released from the post-stenotic human kidney. Eur Heart J 2012; 34:540-548a. [PMID: 22771675 DOI: 10.1093/eurheartj/ehs197] [Citation(s) in RCA: 72] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AIMS The mechanisms mediating kidney injury and repair in humans with atherosclerotic renal artery stenosis (ARAS) remain poorly understood. We hypothesized that the stenotic kidney releases inflammatory mediators and recruits progenitor cells to promote regeneration. METHODS AND RESULTS Essential hypertensive (EH) and ARAS patients (n=24 each) were studied during controlled sodium intake and antihypertensive treatment. Inferior vena cava (IVC) and renal vein (RV) levels of CD34+/KDR+ progenitor cells, cell adhesion molecules, inflammatory biomarkers, progenitor cell homing signals, and pro-angiogenic factors were measured in EH and ARAS, and their gradient and net release compared with systemic levels in matched normotensive controls (n= 24). Blood pressure in ARAS was similar to EH, but the glomerular filtration rate was lower. Renal vein levels of soluble E-Selectin, vascular cell adhesion molecule-1, and several inflammatory markers were higher in the stenotic kidney RV vs. normal and EH RV (P < 0.05), and their net release increased. Similarly, stem-cell homing factor levels increased in the stenotic kidney RV. Systemic CD34+/KDR+ progenitor cell levels were lower in both EH and ARAS and correlated with cytokine levels. Moreover, CD34+/KDR+ progenitor cells developed a negative gradient across the ARAS kidney, suggesting progenitor cell retention. The non-stenotic kidney also showed signs of inflammatory processes, which were more subtle than in the stenotic kidney. CONCLUSION Renal vein blood from post-stenotic human kidneys has multiple markers reflecting active inflammation that portends kidney injury and reduced function. CD34+/KDR+ progenitor cells sequestered within these kidneys may participate in reparative processes. These inflammation-related pathways and limited circulating progenitor cells may serve as novel therapeutic targets to repair the stenotic kidney.
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Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA
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Ebrahimi B, Li Z, Eirin A, Zhu XY, Textor SC, Lerman LO. Addition of endothelial progenitor cells to renal revascularization restores medullary tubular oxygen consumption in swine renal artery stenosis. Am J Physiol Renal Physiol 2012; 302:F1478-85. [PMID: 22419692 PMCID: PMC3378175 DOI: 10.1152/ajprenal.00563.2011] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2011] [Accepted: 03/08/2012] [Indexed: 01/12/2023] Open
Abstract
Renal artery stenosis (RAS) promotes microvascular rarefaction and fibrogenesis, which may eventuate in irreversible kidney injury. We have shown that percutaneous transluminal renal angioplasty (PTRA) or endothelial progenitor cells (EPC) improve renal cortical hemodynamics and function in the poststenotic kidney. The renal medulla is particularly sensitive to hypoxia, yet little is known about reversibility of medullary injury on restoration of renal blood flow. This study was designed to test the hypothesis that PTRA, with or without adjunct EPC delivery to the stenotic kidney, may improve medullary remodeling and tubular function. RAS was induced in 21 pigs using implantation of irritant coils, while another group served as normal controls (n = 7 each). Two RAS groups were then treated 6 wk later with PTRA or both PTRA and EPC. Four weeks later, medullary hemodynamics, microvascular architecture, and oxygen-dependent tubular function of the stenotic kidneys were examined using multidetector computed tomography, microcomputed tomography, and blood oxygenation level-dependent MRI, respectively. Medullary protein expression of vascular endothelial growth factor, endothelial nitric oxide synthase, hypoxia-inducible factor-1α, and NAD(P)H oxidase p47 were determined. All RAS groups showed decreased medullary vascular density and blood flow. However, in RAS+PTRA+EPC animals, EPC were engrafted in tubular structures, oxygen-dependent tubular function was normalized, and fibrosis attenuated, despite elevated expression of hypoxia-inducible factor-1α and sustained downregulation of vascular endothelial growth factor. In conclusion, EPC delivery, in addition to PTRA, restores medullary oxygen-dependent tubular function, despite impaired medullary blood and oxygen supply. These results support further development of cell-based therapy as an adjunct to revascularization of RAS.
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Affiliation(s)
- Behzad Ebrahimi
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
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The intrinsic prostaglandin E2-EP4 system of the renal tubular epithelium limits the development of tubulointerstitial fibrosis in mice. Kidney Int 2012; 82:158-71. [PMID: 22513820 DOI: 10.1038/ki.2012.115] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Inflammatory responses in the kidney lead to tubulointerstitial fibrosis, a common feature of chronic kidney diseases. Here we examined the role of prostaglandin E(2) (PGE(2)) in the development of tubulointerstitial fibrosis. In the kidneys of wild-type mice, unilateral ureteral obstruction leads to progressive tubulointerstitial fibrosis with macrophage infiltration and myofibroblast proliferation. This was accompanied by an upregulation of COX-2 and PGE(2) receptor subtype EP(4) mRNAs. In the kidneys of EP(4) gene knockout mice, however, obstruction-induced histological alterations were significantly augmented. In contrast, an EP(4)-specific agonist significantly attenuated these alterations in the kidneys of wild-type mice. The mRNAs for macrophage chemokines and profibrotic growth factors were upregulated in the kidneys of wild-type mice after ureteral obstruction. This was significantly augmented in the kidneys of EP(4)-knockout mice and suppressed by the EP(4) agonist but only in the kidneys of wild-type mice. Notably, COX-2 and MCP-1 proteins, as well as EP(4) mRNA, were localized in renal tubular epithelial cells after ureteral obstruction. In cultured renal fibroblasts, another EP(4)-specific agonist significantly inhibited PDGF-induced proliferation and profibrotic connective tissue growth factor production. Hence, an endogenous PGE(2)-EP(4) system in the tubular epithelium limits the development of tubulointerstitial fibrosis by suppressing inflammatory responses.
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Warner GM, Cheng J, Knudsen BE, Gray CE, Deibel A, Juskewitch JE, Lerman LO, Textor SC, Nath KA, Grande JP. Genetic deficiency of Smad3 protects the kidneys from atrophy and interstitial fibrosis in 2K1C hypertension. Am J Physiol Renal Physiol 2012; 302:F1455-64. [PMID: 22378822 DOI: 10.1152/ajprenal.00645.2011] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Although the two-kidney, one-clip (2K1C) model is widely used as a model of human renovascular hypertension, mechanisms leading to the development of fibrosis and atrophy in the cuffed kidney and compensatory hyperplasia in the contralateral kidney have not been defined. Based on the well-established role of the transforming growth factor (TGF)-β signaling pathway in renal fibrosis, we tested the hypothesis that abrogation of TGF-β/Smad3 signaling would prevent fibrosis in the cuffed kidney. Renal artery stenosis (RAS) was established in mice with a targeted disruption of exon 2 of the Smad3 gene (Smad3 KO) and wild-type (WT) controls by placement of a polytetrafluoroethylene cuff on the right renal artery. Serial pulse-wave Doppler ultrasound assessments verified that blood flow through the cuffed renal artery was decreased to a similar extent in Smad3 KO and WT mice. Two weeks after surgery, systolic blood pressure and plasma renin activity were significantly elevated in both the Smad3 KO and WT mice. The cuffed kidney of WT mice developed renal atrophy (50% reduction in weight after 6 wk, P < 0.0001), which was associated with the development of interstitial fibrosis, tubular atrophy, and interstitial inflammation. Remarkably, despite a similar reduction of renal blood flow, the cuffed kidney of the Smad3 KO mice showed minimal atrophy (9% reduction in weight, P = not significant), with no significant histopathological alterations (interstitial fibrosis, tubular atrophy, and interstitial inflammation). We conclude that abrogation of TGF-β/Smad3 signaling confers protection against the development of fibrosis and atrophy in RAS.
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Affiliation(s)
- Gina M Warner
- Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA
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35
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Gloviczki ML, Lerman LO, Textor SC. Blood oxygen level-dependent (BOLD) MRI in renovascular hypertension. Curr Hypertens Rep 2012; 13:370-7. [PMID: 21833688 DOI: 10.1007/s11906-011-0218-7] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Establishing whether large vessel occlusive disease threatens tissue oxygenation and viability in the post-stenotic kidney is difficult for clinicians. Development of blood oxygen level-dependent (BOLD) MRI methods can allow functional evaluation of regional differences in deoxyhemoglobin levels within the kidney without requiring contrast. The complex renal circulation normally provides a gradient of oxygenation from a highly vascular cortex to much reduced levels in the deep sections of medulla, dependent upon adjustments in renal afferent arterioles, oxygen consumption related to solute transport, and arteriovenous shunting related to the juxtaposition of descending and ascending vasa recta. Studies with BOLD imaging have identified adaptation to substantial reductions in renal blood flow, volume, and glomerular filtration rate in post-stenotic kidneys that preserves medullary and cortical oxygenation during medical therapy. However, extreme vascular compromise overwhelms these adaptive changes and leads to cortical hypoxia and microvascular injury.
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Affiliation(s)
- Monika L Gloviczki
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
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36
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Textor SC, Lerman LO. Inflammatory cell markers as indicators of atherosclerotic renovascular disease. Clin J Am Soc Nephrol 2012; 7:193-5. [PMID: 22241820 DOI: 10.2215/cjn.12641211] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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Li Z, Woollard JR, Wang S, Korsmo MJ, Ebrahimi B, Grande JP, Textor SC, Lerman A, Lerman LO. Increased glomerular filtration rate in early metabolic syndrome is associated with renal adiposity and microvascular proliferation. Am J Physiol Renal Physiol 2011; 301:F1078-87. [PMID: 21775485 PMCID: PMC3213905 DOI: 10.1152/ajprenal.00333.2011] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2011] [Accepted: 07/14/2011] [Indexed: 12/31/2022] Open
Abstract
Metabolic syndrome (MetS) is associated with glomerular hyperfiltration and is a risk factor for chronic kidney disease, but the underlying mechanisms are poorly defined. This study tested the hypothesis that increased glomerular filtration rate (GFR) in early MetS is associated with renal adiposity and microvascular proliferation. Twelve MetS-prone Ossabaw pigs were randomized to 10 wk of a standard (lean, n = 6) or atherogenic (MetS, n = 6) diet. Kidney hemodynamics and function, perirenal fat volume, and tubular dynamics were assessed in vivo by multidetector computed tomography (CT) and blood oxygen level-dependent (BOLD)-MRI. Microvascular architecture was assessed ex vivo with micro-CT. Candidate injury mechanisms were evaluated in kidney tissue by Western blotting and histology. Basal GFR, renal blood flow, and renal cortical perfusion and volume were elevated in the MetS group. Perirenal and kidney tissue fat, proximal-nephron intratubular fluid concentration, and endothelial nitric oxide synthase expression were increased in MetS. GFR levels correlated with tissue triglyceride levels. Elevated spatial density of 20- to 40-μm cortical microvessels was accompanied by mild oxidative stress, inflammation, and with proximal tubular vacuolization. Medullary size and perfusion were relatively preserved, and BOLD-MRI showed intact medullary tubular response to furosemide. Increased GFR in early MetS is associated with renal adiposity and microvascular proliferation, which involve mainly the renal cortex and precede significant activation of oxidative stress and inflammation. Renal adiposity and proliferative microvessels may represent novel therapeutic targets for preserving renal function in early MetS.
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Affiliation(s)
- Zilun Li
- Department of Internal Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota 55905, USA
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Gloviczki ML, Glockner JF, Crane JA, McKusick MA, Misra S, Grande JP, Lerman LO, Textor SC. Blood oxygen level-dependent magnetic resonance imaging identifies cortical hypoxia in severe renovascular disease. Hypertension 2011; 58:1066-72. [PMID: 22042812 DOI: 10.1161/hypertensionaha.111.171405] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Atherosclerotic renal artery stenosis has a range of manifestations depending on the severity of vascular occlusion. The aim of this study was to examine whether exceeding the limits of adaptation to reduced blood flow ultimately leads to tissue hypoxia, as determined by blood oxygen level dependent MRI. We compared 3 groups of hypertensive patients, 24 with essential hypertension, 13 with "moderate" (Doppler velocities 200-384 cm/s), and 17 with "severe" atherosclerotic renal artery stenosis (ARAS; velocities >384 cm/s and loss of functional renal tissue). Cortical and medullary blood flows and volumes were determined by multidetector computed tomography. Poststenotic kidney size and blood flow were reduced with ARAS, and tissue perfusion fell in the most severe lesions. Tissue medullary deoxyhemoglobin, as reflected by R2* values, was higher as compared with the cortex for all of the groups and did not differ between subjects with renal artery lesions and essential hypertension. By contrast, cortical R2* levels were elevated for severe ARAS (21.6±9.4 per second) as compared with either essential hypertension (17.8±2.3 per second; P<0.01) or moderate ARAS (15.7±2.1 per second; P<0.01). Changes in medullary R2* after furosemide administration tended to be blunted in severe ARAS as compared with unaffected (contralateral) kidneys. These results demonstrate that severe vascular occlusion overwhelms the capacity of the kidney to adapt to reduced blood flow, manifest as overt cortical hypoxia as measured by blood oxygen level-dependent MRI. The level of cortical hypoxia is out of proportion to the medulla and may provide a marker to identify irreversible parenchymal injury.
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Affiliation(s)
- Monika L Gloviczki
- Department of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA.
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39
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Current world literature. Curr Opin Cardiol 2011; 26:576-83. [PMID: 21988836 DOI: 10.1097/hco.0b013e32834d3850] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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40
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Eirin A, Zhu XY, Urbieta-Caceres VH, Grande JP, Lerman A, Textor SC, Lerman LO. Persistent kidney dysfunction in swine renal artery stenosis correlates with outer cortical microvascular remodeling. Am J Physiol Renal Physiol 2011; 300:F1394-401. [PMID: 21367913 PMCID: PMC3119141 DOI: 10.1152/ajprenal.00697.2010] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 03/01/2011] [Indexed: 11/22/2022] Open
Abstract
Percutaneous transluminal renal stenting (PTRS) does not consistently improve renal function in patients with atherosclerotic renovascular disease, but the mechanisms underlying irreversible kidney injury have not been fully elucidated. We hypothesized that renal dysfunction after PTRS is linked to ongoing renal microvascular (MV) remodeling. Pigs were studied after 10 wk of atherosclerosis and renal artery stenosis (ARAS), ARAS treated with PTRS 4 wk earlier, and normal controls (n = 10 each). Renal blood flow (RBF) and glomerular filtration rate (GFR) were studied using multidetector computer tomography. Renal microvascular architecture (micro-CT), angiogenic activity, oxidative stress, and fibrosis were evaluated ex vivo. Four weeks after PTRS, blood pressure was normalized. However, GFR and RBF remained similarly decreased in untreated ARAS and ARAS+PTRS (P < 0.05 vs. normal). MV rarefaction was unaltered after revascularization, and the spatial density of outer cortical microvessels correlated with residual GFR. Interstitial fibrosis and altered expression of proangiogenic and profibrotic factors persisted after PTRS. Tubulointerstitial injury in ARAS persisted 4 wk after mechanically successful PTRS, and vessel loss correlated with residual renal dysfunction. MV loss and fibrosis in swine ARAS might account for persistent renal dysfunction after PTRS and underscore the need to assess renal parenchymal disease before revascularization.
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Affiliation(s)
- Alfonso Eirin
- Department of Internal Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota 55905, USA
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Reversal of experimental renovascular hypertension restores coronary microvascular function and architecture. Am J Hypertens 2011; 24:458-65. [PMID: 21233798 DOI: 10.1038/ajh.2010.259] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND Hypertension (HTN) may lead to left ventricular hypertrophy and vascular dysfunction, which are independent factors for adverse cardiovascular outcomes. We hypothesized that decreased blood pressure by percutaneous transluminal renal angioplasty (PTRA) would improve the function and architecture of coronary microvessels, in association with decreased inflammation and fibrosis. METHODS Three groups of pigs were studied: normal, HTN, and HTN+PTRA. After 6 weeks of renovascular HTN, induced by placing a local-irritant coil in the renal artery, pigs underwent PTRA or sham. Four weeks later multidetector-computed tomography (CT) was used to assess systolic, diastolic, and microvascular function, and responses to adenosine. Microvascular architecture, oxygen sensors, inflammation, and fibrosis were then explored in cardiac tissue. RESULTS PTRA successfully decreased blood pressure and left ventricular hypertrophy. Basal fractional vascular volume (FVV) was similar among the groups, but its response to adenosine was significantly attenuated in HTN, whereas microvascular permeability (MP) and response to adenosine were greater than normal. Both were restored by PTRA. These were accompanied by increased myocardial expression of hypoxia-inducible factor (HIF)-1α, inflammation, and microvascular remodeling, including increased density of epicardial microvessels (20-200 µm), as well as cardiac diastolic dysfunction, all of which improved by reversal of HTN. However, PTRA only partially decreased myocardial fibrosis. CONCLUSIONS Reversal of early renovascular HTN improved coronary microvascular function and architecture and reversed myocardial hypertrophy and diastolic dysfunction, in association with decreased levels of myocardial ischemia and inflammation markers, underscoring the benefits of blood pressure normalization for preservation of cardiovascular function and structure.
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Contribution of large pig for renal ischemia-reperfusion and transplantation studies: the preclinical model. J Biomed Biotechnol 2011; 2011:532127. [PMID: 21403881 PMCID: PMC3051176 DOI: 10.1155/2011/532127] [Citation(s) in RCA: 125] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2010] [Revised: 12/21/2010] [Accepted: 01/03/2011] [Indexed: 01/08/2023] Open
Abstract
Animal experimentation is necessary to characterize human diseases and design adequate therapeutic interventions. In renal transplantation research, the limited number of in vitro models involves a crucial role for in vivo models and particularly for the porcine model. Pig and human kidneys are anatomically similar (characterized by multilobular structure in contrast to rodent and dog kidneys unilobular). The human proximity of porcine physiology and immune systems provides a basic knowledge of graft recovery and inflammatory physiopathology through in vivo studies. In addition, pig large body size allows surgical procedures similar to humans, repeated collections of peripheral blood or renal biopsies making pigs ideal for medical training and for the assessment of preclinical technologies. However, its size is also its main drawback implying expensive housing. Nevertheless, pig models are relevant alternatives to primate models, offering promising perspectives with developments of transgenic modulation and marginal donor models facilitating data extrapolation to human conditions.
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Urbieta Caceres VH, Lin J, Zhu XY, Favreau FD, Gibson ME, Crane JA, Lerman A, Lerman LO. Early experimental hypertension preserves the myocardial microvasculature but aggravates cardiac injury distal to chronic coronary artery obstruction. Am J Physiol Heart Circ Physiol 2010; 300:H693-701. [PMID: 21131477 DOI: 10.1152/ajpheart.00516.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Coronary artery disease is a leading cause of death. Hypertension (HT) increases the incidence of cardiac events, but its effect on cardiac adaptation to coexisting coronary artery stenosis (CAS) is unclear. We hypothesized that concurrent HT modulates microvascular function in chronic CAS and aggravates microvascular remodeling and myocardial injury. Four groups of pigs (n=6 each) were studied: normal, CAS, HT, and CAS+HT. CAS and HT were induced by placing local irritant coils in the left circumflex coronary artery and renal artery, respectively. Six weeks later multidetector computerized tomography (CT) was used to assess systolic and diastolic function, microvascular permeability, myocardial perfusion, and responses to adenosine in the "area at risk." Microvascular architecture, inflammation, and fibrosis were then explored in cardiac tissue. Basal myocardial perfusion was similarly decreased in CAS and CAS+HT, but its response to adenosine was significantly more attenuated in CAS. Microvascular permeability in CAS+HT was greater than in CAS and was accompanied by amplified myocardial inflammation, fibrosis, and microvascular remodeling, as well as cardiac systolic and diastolic dysfunction. On the other hand, compared with normal, micro-CT-derived microvascular (20-200 μm) transmural density decreased in CAS but not in HT or CAS+HT. We conclude that the coexistence of early renovascular HT exacerbated myocardial fibrosis and vascular remodeling distal to CAS. These changes were not mediated by loss of myocardial microvessels, which were relatively preserved, but possibly by exacerbated myocardial inflammation and fibrosis. HT modulates cardiac adaptive responses to CAS and bears cardiac functional consequences.
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Liu CM, Ma JQ, Lou Y. Chronic administration of troxerutin protects mouse kidney against d-galactose-induced oxidative DNA damage. Food Chem Toxicol 2010; 48:2809-17. [DOI: 10.1016/j.fct.2010.07.011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2010] [Revised: 06/17/2010] [Accepted: 07/08/2010] [Indexed: 10/19/2022]
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