51
|
Szeto HH. First-in-class cardiolipin-protective compound as a therapeutic agent to restore mitochondrial bioenergetics. Br J Pharmacol 2014; 171:2029-50. [PMID: 24117165 PMCID: PMC3976620 DOI: 10.1111/bph.12461] [Citation(s) in RCA: 360] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 09/06/2013] [Accepted: 10/01/2013] [Indexed: 12/16/2022] Open
Abstract
A decline in energy is common in aging, and the restoration of mitochondrial bioenergetics may offer a common approach for the treatment of numerous age-associated diseases. Cardiolipin is a unique phospholipid that is exclusively expressed on the inner mitochondrial membrane where it plays an important structural role in cristae formation and the organization of the respiratory complexes into supercomplexes for optimal oxidative phosphorylation. The interaction between cardiolipin and cytochrome c determines whether cytochrome c acts as an electron carrier or peroxidase. Cardiolipin peroxidation and depletion have been reported in a variety of pathological conditions associated with energy deficiency, and cardiolipin has been identified as a target for drug development. This review focuses on the discovery and development of the first cardiolipin-protective compound as a therapeutic agent. SS-31 is a member of the Szeto-Schiller (SS) peptides known to selectively target the inner mitochondrial membrane. SS-31 binds selectively to cardiolipin via electrostatic and hydrophobic interactions. By interacting with cardiolipin, SS-31 prevents cardiolipin from converting cytochrome c into a peroxidase while protecting its electron carrying function. As a result, SS-31 protects the structure of mitochondrial cristae and promotes oxidative phosphorylation. SS-31 represents a new class of compounds that can recharge the cellular powerhouse and restore bioenergetics. Extensive animal studies have shown that targeting such a fundamental mechanism can benefit highly complex diseases that share a common pathogenesis of bioenergetics failure. This review summarizes the mechanisms of action and therapeutic potential of SS-31 and provides an update of its clinical development programme.
Collapse
Affiliation(s)
- Hazel H Szeto
- Research Program in Mitochondrial Therapeutics, Department of Pharmacology, Joan and Sanford I. Weill Medical College of Cornell UniversityNew York, NY, USA
| |
Collapse
|
52
|
Renovascular hypertension: is there still a role for stent revascularization? Curr Opin Nephrol Hypertens 2014; 22:525-30. [PMID: 23917028 DOI: 10.1097/mnh.0b013e328363ffe0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
PURPOSE OF REVIEW Management of renovascular hypertension remains controversial and problematic, in part, due to failure of prospective trials to demonstrate added benefit to revascularization. RECENT FINDINGS Effective drug therapy often can achieve satisfactory blood pressure control, although concerns persist of the potential for progressive, delayed loss of kidney function beyond a stenotic lesion. Recent studies highlight benefits of renal artery stenting in subsets of patients including those with recurrent pulmonary edema and those intolerant to blockade of the renin-angiotensin system. Occasional patients with recent deterioration in renal function recover sufficient glomerular filtration rate after stenting to avoid requirements for renal replacement therapy. Emerging paradigms from both clinical and experimental studies suggest that hypoxic injury within the kidney activates inflammatory injury pathways and microvascular rarification that may not recover after technically successful revascularization alone. Initial data suggest that additional measures to repair the kidney, including the use of cell-based therapy, may offer the potential to recover kidney function in advanced renovascular disease. SUMMARY Specific patient groups benefit from renal revascularization. Nephrologists will increasingly be asked to manage complex renovascular patients, different from those in randomized trials, that require intensely individualized management.
Collapse
|
53
|
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.
Collapse
Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota
| | | |
Collapse
|
54
|
Abstract
An intact microcirculation is vital for diffusion of oxygen and nutrients and for removal of toxins of every organ and system in the human body. The functional and/or anatomical loss of microvessels is known as rarefaction, which can compromise the normal organ function and have been suggested as a possible starting point of several diseases. The purpose of this overview is to discuss the potential underlying mechanisms leading to renal microvascular rarefaction, and the potential consequences on renal function and on the progression of renal damage. Although the kidney is a special organ that receives much more blood than its metabolic needs, experimental and clinical evidence indicates that renal microvascular rarefaction is associated to prevalent cardiovascular diseases such as diabetes, hypertension, and atherosclerosis, either as cause or consequence. On the other hand, emerging experimental evidence using progenitor cells or angiogenic cytokines supports the feasibility of therapeutic interventions capable of modifying the progressive nature of microvascular rarefaction in the kidney. This overview will also attempt to discuss the potential renoprotective mechanisms of the therapeutic targeting of the renal microcirculation.
Collapse
Affiliation(s)
- Alejandro R Chade
- The Department of Physiology and Biophysics, Center for Excellence in Cardiovascular-Renal Research, University of Mississippi Medical Center, Jackson, Mississippi, USA.
| |
Collapse
|
55
|
Eirin A, Zhang X, Zhu XY, Tang H, Jordan KL, Grande JP, Dietz AB, Lerman A, Textor SC, Lerman LO. Renal vein cytokine release as an index of renal parenchymal inflammation in chronic experimental renal artery stenosis. Nephrol Dial Transplant 2013; 29:274-82. [PMID: 24097799 DOI: 10.1093/ndt/gft305] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Renal parenchymal inflammation is a critical determinant of kidney injury in renal artery stenosis (RAS) but is difficult to assess in the single kidney without tissue samples. Whether renal vein (RV) levels of inflammatory markers reflect active parenchymal inflammation remains unknown. We evaluated the relationship between net RV cytokine release and tissue inflammation in the post-stenotic kidney. METHODS Pigs were studied after 10 weeks of RAS treated 4 weeks earlier with intra-renal vehicle or anti-inflammatory mesenchymal stem cells (MSCs) or normal control. Single-kidney renal blood flow was measured by fast computerized tomography. RV and inferior vena cava levels of tumor necrosis factor (TNF)-α, interferon (IF)-γ, monocyte chemoattractant protein (MCP-1) and interleukin (IL)-10 were measured by enzyme-linked immunosorbent assay, and their net release calculated. Renal expression of the same cytokines was correlated with their net release. RESULTS Net release of TNF-α, IF-γ and MCP-1 was higher in RAS compared with normal and to the contralateral kidney (all P<0.05), decreased in MSC-treated pigs as was their tissue expression. Contrarily, the release of the anti-inflammatory IL-10 was lower in RAS and normalized in RAS+MSC. The net release of TNF-α, MCP-1 and IL-10 directly correlated with their tissue expression. The ratio of inflammatory-to-reparative macrophages directly correlated with the release of MCP-1, but inversely with the release of IL-10. In vitro cultured MSCs also induced a shift in the macrophage phenotype from inflammatory (M1) to reparative (M2). CONCLUSIONS Our findings demonstrate that the release of inflammatory markers from the affected kidney provides an index of renal tissue inflammation in experimental RAS.
Collapse
Affiliation(s)
- Alfonso Eirin
- Department of Internal Medicine, Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
56
|
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.
Collapse
|
57
|
|
58
|
Saad A, Herrmann SMS, Crane J, Glockner JF, McKusick MA, Misra S, Eirin A, Ebrahimi B, Lerman LO, Textor SC. Stent revascularization restores cortical blood flow and reverses tissue hypoxia in atherosclerotic renal artery stenosis but fails to reverse inflammatory pathways or glomerular filtration rate. Circ Cardiovasc Interv 2013; 6:428-35. [PMID: 23899868 DOI: 10.1161/circinterventions.113.000219] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
BACKGROUND Atherosclerotic renal artery stenosis (ARAS) is known to reduce renal blood flow, glomerular filtration rate (GFR) and amplify kidney hypoxia, but the relationships between these factors and tubulointerstitial injury in the poststenotic kidney are poorly understood. The purpose of this study was to examine the effect of renal revascularization in ARAS on renal tissue hypoxia and renal injury. METHODS AND RESULTS Inpatient studies were performed in patients with ARAS (n=17; >60% occlusion) before and 3 months after stent revascularization, or in patients with essential hypertension (n=32), during fixed Na(+) intake and angiotensin converting enzyme/angiotensin receptors blockers Rx. Single kidney cortical, medullary perfusion, and renal blood flow were measured using multidetector computed tomography, and GFR by iothalamate clearance. Tissue deoxyhemoglobin levels (R(2)*) were measured by blood oxygen level-dependent MRI at 3T, as was fractional kidney hypoxia (percentage of axial area with R(2)*>30/s). In addition, we measured renal vein levels of neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α. Pre-stent single kidney renal blood flow, perfusion, and GFR were reduced in the poststenotic kidney. Renal vein neutrophil gelatinase-associated lipocalin, tumor necrosis factor-α, monocyte chemoattractant protein-1, and fractional hypoxia were higher in untreated ARAS than in essential hypertension. After stent revascularization, fractional hypoxia fell (P<0.002) with increased cortical perfusion and blood flow, whereas GFR and neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and tumor necrosis factor-α remained unchanged. CONCLUSIONS These data demonstrate that despite reversal of renal hypoxia and partial restoration of renal blood flow after revascularization, inflammatory cytokines and injury biomarkers remained elevated and GFR failed to recover in ARAS. Restoration of vessel patency alone failed to reverse tubulointerstitial damage and partly explains the limited clinical benefit of renal stenting. These results identify potential therapeutic targets for recovery of kidney function in renovascular disease.
Collapse
Affiliation(s)
- Ahmed Saad
- Division of Nephrology and Hypertension, and Department of Radiology, Mayo Clinic, Rochester, MN, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
59
|
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.
Collapse
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:
| |
Collapse
|
60
|
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.
Collapse
Affiliation(s)
- Xin Zhang
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
61
|
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.
Collapse
Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
62
|
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.
Collapse
Affiliation(s)
- Alfonso Eirin
- Divisions of Nephrology and Hypertension, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
63
|
Eirin A, Li Z, Zhang X, Krier JD, Woollard JR, Zhu XY, Tang H, Herrmann SM, Lerman A, Textor SC, Lerman LO. A mitochondrial permeability transition pore inhibitor improves renal outcomes after revascularization in experimental atherosclerotic renal artery stenosis. Hypertension 2012; 60:1242-9. [PMID: 23045468 DOI: 10.1161/hypertensionaha.112.199919] [Citation(s) in RCA: 101] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Revascularization improves blood pressure but not renal function in most patients with atherosclerotic renal artery stenosis (ARAS), possibly related to injury incurred during renal reperfusion. Bendavia, a novel tetrapeptide that inhibits mitochondrial permeability transition pore opening, reduces apoptosis, oxidative stress, and ischemia-reperfusion injury in experimental models. However, its potential for improving renal response to revascularization of chronic ARAS is unknown. We hypothesized that adjunct Bendavia would improve renal structure and function after percutaneous transluminal renal angioplasty (PTRA). Pigs were treated after 6 weeks of ARAS or control with PTRA+stenting (or sham), adjunct continuous 4-hour infusion of Bendavia (0.05 mg/kg IV) or vehicle (n=7 each) during PTRA. Single-kidney renal blood flow and glomerular filtration rate were studied 4 weeks later and renal mitochondrial biogenesis, microvascular architecture, and injurious pathways evaluated ex vivo. Monocyte chemoattractant protein-1 levels rose after PTRA, suggesting inflammatory injury. Bendavia did not immediately affect inflammatory cytokine levels, yet 4 weeks later, stenotic kidney renal blood flow and glomerular filtration rate both improved (44.00 ± 0.21% and 36.40 ± 10.21%, respectively) in ARAS+PTRA+Bendavia compared with ARAS+PTRA+vehicle. Renal mitochondrial biogenesis was restored after PTRA+Bendavia, and microvascular rarefaction, apoptosis, oxidative stress, tubular injury, and fibrosis decreased. Infusion of Bendavia during PTRA preserved mitochondrial biogenesis, renal hemodynamics, and function, and attenuated tissue injury in swine ARAS. Thus, functional mitochondrial injury during renal reperfusion may sustain renal inflammatory injury and limit kidney recovery after PTRA. Potent antiapoptotic and antioxidant effects provide Bendavia a novel therapeutic potential for improving kidney outcomes after PTRA in experimental ARAS.
Collapse
Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, 200 First St SW, Rochester, MN 55905, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
64
|
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.
Collapse
Affiliation(s)
- Alfonso Eirin
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minnesota 55905, USA
| | | | | | | | | | | | | | | | | |
Collapse
|
65
|
Eirin A, Ebrahimi B, Lerman LO. Cell-Based Therapies as an Adjunct to Revascularization in Experimental Atherosclerotic Reno Vascular Disease. JOURNAL OF CLINICAL & EXPERIMENTAL CARDIOLOGY 2012; 3. [PMID: 24319626 DOI: 10.4172/2155-9880.1000e108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Alfonso Eirin
- Department of Internal Medicine, Mayo Clinic, Rochester, MN, USA
| | | | | |
Collapse
|
66
|
Urbieta-Caceres VH, Syed FA, Lin J, Zhu XY, Jordan KL, Bell CC, Bentley MD, Lerman A, Khosla S, Lerman LO. Age-dependent renal cortical microvascular loss in female mice. Am J Physiol Endocrinol Metab 2012; 302:E979-86. [PMID: 22318944 PMCID: PMC3330723 DOI: 10.1152/ajpendo.00411.2011] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Renal function and blood flow decline during aging in association with a decrease in the number of intrarenal vessels, but if loss of estrogen contributes to this microvascular, rarefaction remains unclear. We tested the hypothesis that the decreased renal microvascular density with age is aggravated by loss of estrogen. Six-month-old female C57/BL6 mice underwent ovariectomy (Ovx) or sham operation and then were allowed to age to 18-22 mo. Another comparable group was replenished with estrogen after Ovx (Ovx+E), while a 6-mo-old group served as young controls. Kidneys were then dissected for evaluation of microvascular density (by micro-computed tomography) and angiogenic and fibrogenic factors. Cortical density of small microvessels (20-200 μm) was decreased in all aged groups compared with young controls (30.3 ± 5.8 vessels/mm², P < 0.05), but tended to be lower in sham compared with Ovx and Ovx+E (9.9 ± 1.7 vs. 17.2 ± 4.2 and 18 ± 3.0 vessels/mm², P = 0.08 and P = 0.02, respectively). Cortical density of larger microvessels (200-500 μm) decreased only in aged sham (P = 0.04 vs. young control), and proangiogenic signaling was attenuated. On the other hand, renal fibrogenic mechanisms were aggravated in aged Ovx compared with aged sham, but blunted in Ovx+E, in association with downregulated transforming growth factor-β signaling and decreased oxidative stress in the kidney. Therefore, aging induced in female mice renal cortical microvascular loss, which was likely not mediated by loss of endogenous estrogen. However, estrogen may play a role in protecting the kidney by decreasing oxidative stress and attenuating mechanisms linked to renal interstitial fibrosis.
Collapse
|
67
|
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.
Collapse
Affiliation(s)
- Monika L Gloviczki
- Division of Nephrology and Hypertension, Mayo Clinic, Rochester, MN 55905, USA
| | | | | |
Collapse
|
68
|
Urbieta-Caceres VH, Zhu XY, Jordan KL, Tang H, Textor K, Lerman A, Lerman LO. Selective improvement in renal function preserved remote myocardial microvascular integrity and architecture in experimental renovascular disease. Atherosclerosis 2011; 221:350-8. [PMID: 22341593 DOI: 10.1016/j.atherosclerosis.2011.10.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Revised: 09/20/2011] [Accepted: 10/01/2011] [Indexed: 11/19/2022]
Abstract
AIM Atherosclerotic renovascular disease (ARVD) may impair renal function and increase cardiovascular morbidity and mortality, but the mechanism by which ARVD impacts cardiovascular function is unclear. We tested the hypothesis that preservation of renal function can reverse cardiac dysfunction in ARVD. METHODS AND RESULTS Endothelial progenitor cells (EPC) were injected intra-renally (ARVD+EPC) after 6 weeks of swine ARVD (concurrent hypercholesterolemia and renovascular hypertension), and single-kidney function and myocardial blood-flow and microvascular permeability (MP) responses to adenosine were assessed using CT 4 weeks later. Myocardial microvascular density was evaluated by micro-CT. Inflammation and oxidative-stress were assessed in kidney venous and systemic blood samples. Normal and untreated ARVD pigs served as controls. Blood pressure was similarly increased in ARVD and ARVD+EPC. Compared to normal, ARVD showed lower glomerular filtration rate, elevated renal vein and systemic oxidized LDL (ox-LDL), aldosterone, uric acid, isoprostanes, transforming growth factor (TGF)-β, and interleukine-6. Renal vein ox-LDL and TGF-β showed a positive gradient across the stenotic kidney, indicating increased renal oxidative stress and fibrogenic activity. Furthermore, ARVD impaired myocardial blood-flow and MP response to adenosine, decreased microvascular density, and induced myocardial fibrosis. Improvement of renal function in ARVD+EPC decreased systemic aldosterone, inflammation, and oxidative stress, and improved myocardial microvascular integrity and density. CONCLUSION Selective improvement in renal function, which reduced renal and systemic oxidative stress and inflammation, preserved remote myocardial microvascular function and architecture, despite enduring hypertension. These findings underscore functionally important cardiorenal crosstalk possibly mediated by renal injury signals.
Collapse
|