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Butenas ALE, Flax JS, Carroll RJ, Chuwonganant CS, Baranczuk AM, Copp SW. Sex differences in the purinergic 2 receptor-mediated blood pressure response to treadmill exercise in rats with simulated peripheral artery disease. Am J Physiol Regul Integr Comp Physiol 2024; 326:R449-R460. [PMID: 38497127 DOI: 10.1152/ajpregu.00010.2024] [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: 01/16/2024] [Revised: 03/13/2024] [Accepted: 03/14/2024] [Indexed: 03/19/2024]
Abstract
We investigated the role played by ATP-sensitive purinergic 2 (P2) receptors in evoking the pressor response to treadmill exercise in male and female rats with and without femoral arteries that were ligated for ∼72 h to induce simulated peripheral artery disease (PAD). We hypothesized that PPADS (P2 receptor antagonist, 10 mg iv) would reduce the pressor response to 4 min of treadmill exercise (15 m·min-1, 1° incline) and steady-state exercise plasma norepinephrine (NE) values in male and female rats, and that the magnitude of effect of PPADS would be greater in rats with simulated PAD ("ligated") than in sham-operated rats. In males, PPADS significantly reduced the difference between steady-state exercise and baseline mean arterial pressure (ΔMAP) response to treadmill exercise in sham (n = 8; pre-PPADS: 12 ± 2, post-PPADS: 1 ± 5 mmHg; P = 0.037) and ligated (n = 4; pre-PPADS: 20 ± 2, post-PPADS: 11 ± 3 mmHg; P = 0.028) rats with a similar magnitude of effect observed between groups (P = 0.720). In females, PPADS had no effect on the ΔMAP response to treadmill exercise in sham (n = 6; pre-PPADS: 9 ± 2, post-PPADS: 7 ± 2 mmHg; P = 0.448) or ligated (n = 6; pre-PPADS: 15 ± 2, post-PPADS: 16 ± 3 mmHg; P = 0.684) rats. When NE values were grouped by sex independent of ligation/sham status, PPADS significantly reduced plasma NE in male (P = 0.016) and female (P = 0.027) rats. The data indicate that P2 receptors contribute to the sympathetic response to exercise in both male and female rats but that the sympathoexcitatory role for P2 receptors translates into an obligatory role in the blood pressure response to exercise in male but not in female rats.NEW & NOTEWORTHY Here, we demonstrate that purinergic 2 (P2) receptors contribute significantly to the blood pressure response to treadmill exercise in male rats both with and without simulated PAD induced by femoral artery ligation. We found no role for P2 receptors in the blood pressure response to treadmill exercise in female rats, thus revealing clear sex differences in P2 receptor-mediated blood pressure control during exercise.
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Affiliation(s)
- Alec L E Butenas
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Joseph S Flax
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Raimi J Carroll
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - C Shane Chuwonganant
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Ashley M Baranczuk
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
| | - Steven W Copp
- Department of Kinesiology, Kansas State University, Manhattan, Kansas, United States
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Esteves M, Monteiro MP, Duarte JA. Role of Regular Physical Exercise in Tumor Vasculature: Favorable Modulator of Tumor Milieu. Int J Sports Med 2020; 42:389-406. [PMID: 33307553 DOI: 10.1055/a-1308-3476] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The tumor vessel network has been investigated as a precursor of an inhospitable tumor microenvironment, including its repercussions in tumor perfusion, oxygenation, interstitial fluid pressure, pH, and immune response. Dysfunctional tumor vasculature leads to the extravasation of blood to the interstitial space, hindering proper perfusion and causing interstitial hypertension. Consequently, the inadequate delivery of oxygen and clearance of by-products of metabolism promote the development of intratumoral hypoxia and acidification, hampering the action of immune cells and resulting in more aggressive tumors. Thus, pharmacological strategies targeting tumor vasculature were developed, but the overall outcome was not satisfactory due to its transient nature and the higher risk of hypoxia and metastasis. Therefore, physical exercise emerged as a potential favorable modulator of tumor vasculature, improving intratumoral vascularization and perfusion. Indeed, it seems that regular exercise practice is associated with lasting tumor vascular maturity, reduced vascular resistance, and increased vascular conductance. Higher vascular conductance reduces intratumoral hypoxia and increases the accessibility of circulating immune cells to the tumor milieu, inhibiting tumor development and improving cancer treatment. The present paper describes the implications of abnormal vasculature on the tumor microenvironment and the underlying mechanisms promoted by regular physical exercise for the re-establishment of more physiological tumor vasculature.
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Affiliation(s)
- Mário Esteves
- Laboratory of Biochemistry and Experimental Morphology, CIAFEL, Porto, Portugal.,Department of Physical Medicine and Rehabilitation, Hospital-Escola, Fernando Pessoa University, Gondomar, Portugal
| | - Mariana P Monteiro
- Unit for Multidisciplinary Research in Biomedicine, Instituto de Ciências Biomédicas Abel Salazar, University of Porto, Porto, Portugal
| | - Jose Alberto Duarte
- CIAFEL - Faculty of Sport, University of Porto, Porto, Portugal.,Instituto Universitário de Ciências da Saúde, Gandra, Portugal
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3
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Arciero J, Lembcke L, Burch M, Franko E, Unthank J. Assessing the hemodynamic contribution of capillaries, arterioles, and collateral arteries to vascular adaptations in arterial insufficiency. Microcirculation 2020; 27:e12591. [PMID: 31520431 PMCID: PMC8745030 DOI: 10.1111/micc.12591] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 08/19/2019] [Accepted: 09/09/2019] [Indexed: 12/19/2022]
Abstract
OBJECTIVE There is currently a lack of clarity regarding which vascular segments contribute most significantly to flow compensation following a major arterial occlusion. This study uses hemodynamic principles and computational modeling to demonstrate the relative contributions of capillaries, arterioles, and collateral arteries at rest or exercise following an abrupt, total, and sustained femoral arterial occlusion. METHODS The vascular network of the simulated rat hindlimb is based on robust measurements of blood flow and pressure in healthy rats from exercise and training studies. The sensitivity of calf blood flow to acute or chronic vascular adaptations in distinct vessel segments is assessed. RESULTS The model demonstrates that decreasing the distal microcirculation resistance has almost no effect on flow compensation, while decreasing collateral arterial resistance is necessary to restore resting calf flow following occlusion. Full restoration of non-occluded flow is predicted under resting conditions given all chronic adaptations, but only 75% of non-occluded flow is restored under exercise conditions. CONCLUSION This computational method establishes the hemodynamic significance of acute and chronic adaptations in the microvasculature and collateral arteries under rest and exercise conditions. Regardless of the metabolic level being simulated, this study consistently shows the dominating significance of collateral vessels following an occlusion.
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Affiliation(s)
- Julia Arciero
- Department of Mathematical Sciences, IUPUI, Indianapolis, IN 46202
| | - Lauren Lembcke
- Department of Mathematics, Clemson University, Clemson, SC 29634
| | - Myson Burch
- Department of Mathematics, Purdue University
| | - Elizabeth Franko
- Department of Mathematics, University of Scranton, Scranton, PA 18510
| | - Joseph Unthank
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN 46202
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Souza DÚF, Monteiro DP, Pinto RZ, Pereira DAG. Supervised Exercise Therapy for Intermittent Claudication. Phys Ther 2020; 100:8-13. [PMID: 31612216 DOI: 10.1093/ptj/pzz140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 12/08/2018] [Accepted: 06/10/2019] [Indexed: 11/13/2022]
Abstract
<LEAP> Highlights the findings and application of Cochrane reviews and other evidence pertinent to the practice of physical therapy. The Cochrane Library is a respected source of reliable evidence related to health care. Cochrane systematic reviews explore the evidence for and against the effectiveness and appropriateness of interventions-medication, surgery, education, nutrition, and exercise-and the evidence for and against the use of diagnostic tests for specific conditions. Cochrane reviews are designed to facilitate the decisions of clinicians, patients, and others in health care by providing a careful review and interpretation of research studies published in the scientific literature. Each article in this Physical Therapy (PTJ) series will summarize a Cochrane review or other scientific evidence resource on a single topic and will present clinical scenarios based on real patients to illustrate how the results of the review can be used to directly inform clinical decisions. This article focuses on the effectiveness of supervised exercise therapy for intermittent claudication. Can supervised exercise therapy help a person with intermittent claudication?
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Kutty S, Liu N, Zhou J, Xiao Y, Wu J, Danford D, Lof J, Xie F, Porter TR. ULTRASOUND INDUCED MICROBUBBLE CAVITATION FOR THE TREATMENT OF CATHETERIZATION INDUCED VASOSPASM. ACTA ACUST UNITED AC 2017; 2:748-756. [PMID: 29349360 PMCID: PMC5769697 DOI: 10.1016/j.jacbts.2017.07.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Shelby Kutty
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - Na Liu
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE.,Department of Cardiology and Cardiac Catheterization Lab, Second Xiangya Hospital, Central South University, Changsha, China
| | - Jia Zhou
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE.,Department of Ultrasonography, the First Affiliated Hospital of University of South China, Hengyang, China
| | - Yunbin Xiao
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - Juefei Wu
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - David Danford
- Division of Pediatric Cardiology, University of Nebraska College of Medicine/Children's Hospital & Medical Center, Omaha, NE
| | - John Lof
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - Feng Xie
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
| | - Thomas R Porter
- Department of Internal Medicine, Section of Cardiology, University of Nebraska Medical Center, Omaha, NE
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Affiliation(s)
- Naomi M. Hamburg
- Whitaker Cardiovascular Institute, Boston University School of Medicine
- the Section of Vascular Biology, Department of Medicine, Boston Medical Center
| | - Mark A. Creager
- Dartmouth-Hitchcock Heart and Vascular Center and the Geisel School of Medicine at Dartmouth
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Karimian J, Khazaei M, Shekarchizadeh P. Effect of Resistance Training on Capillary Density Around Slow and Fast Twitch Muscle Fibers in Diabetic and Normal Rats. Asian J Sports Med 2015; 6:e24040. [PMID: 26715966 PMCID: PMC4691304 DOI: 10.5812/asjsm.24040] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2013] [Accepted: 03/04/2014] [Indexed: 01/22/2023] Open
Abstract
Background: It is well accepted that skeletal muscle conforms to exercise stimulus by increasing capillary density and angiogenesis, but there is less evidence regarding the effect of resistance training on capillary density in flexor hallucis longus (FHL) and soleus muscle. Objectives: In this study, we evaluated the effect of resistance training on capillary density around soleus and FHL muscles in type 1 diabetic rats. Materials and Methods: Thirty-six male rats were divided into four groups: (1) control; (2) diabetic; (3) diabetic trained and (4) control trained (n = 9 each). A Single intraperitoneal injection of Streptozotocin at a dose of 55 mg/kg was used for induction of diabetes. The rats in the trained group undertook one training session per day for 3 days/week. Training was done with the use of a 1 meter high ladder inclined at 80°. After 4 weeks, the plasma nitrite concentrations were measured. Capillary/fiber ratio was determined around soleus and FHL muscles by immunohistochemistry. Results: Plasma Nitric Oxide (NO) concentration was increased after resistance training in diabetic animals (P < 0.05). Capillary/fiber ratio around the soleus muscle of diabetic group was more than control rats. Resistance training did not alter capillary/fiber ratio in diabetic animals (1.00 ± 0.6 vs. 1.07 ± 0.07, respectively). Capillary/fiber ratio around FHL muscle was significantly different between diabetic and control and did not alter after exercise (diabetes: 1.1702 ± 0.09; diabetic trained: 1.1714 ± 0.08; control: 0.79 ± 0.08; control trained: 0.73 ± 0.03). There was a positive correlation between plasma NO concentration and capillary density in the soleus muscle (R2 = 0.65). Conclusions: Resistance training could not improve capillary/fiber ratio in soleus and FHL muscle of diabetic animals in spite of increase in some angiogenic factors including NO.
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Affiliation(s)
- Jahangir Karimian
- Department of School Management And Medical Informatics, Isfahan University of Medical Sciences, Isfahan, IR Iran
| | - Majid Khazaei
- Neurogenic Inflammation Research Centre and Department of Physiology, School of medicine, Mashhad University of Medical Sciences, Mashhad, IR Iran
| | - Parivash Shekarchizadeh
- Department of School Management And Medical Informatics, Isfahan University of Medical Sciences, Isfahan, IR Iran
- Corresponding author: Parivash Shekarchizadeh, Department of School Management and Medical Informatics, Isfahan University of Medical Sciences, Isfahan, IR Iran. Tel: +98-3117922026, E-mail:
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Ziegler MA, DiStasi MR, Miller SJ, Dalsing MC, Unthank JL. Novel method to assess arterial insufficiency in rodent hind limb. J Surg Res 2015; 201:170-80. [PMID: 26850199 DOI: 10.1016/j.jss.2015.10.033] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Revised: 09/25/2015] [Accepted: 10/23/2015] [Indexed: 02/07/2023]
Abstract
BACKGROUND Lack of techniques to assess maximal blood flow capacity thwarts the use of rodent models of arterial insufficiency to evaluate therapies for intermittent claudication. We evaluated femoral vein outflow (VO) in combination with stimulated muscle contraction as a potential method to assess functional hind limb arterial reserve and therapeutic efficacy in a rodent model of subcritical limb ischemia. MATERIALS AND METHODS VO was measured with perivascular flow probes at rest and during stimulated calf muscle contraction in young, healthy rats (Wistar Kyoto, WKY; lean Zucker rats, LZR) and rats with cardiovascular risk factors (spontaneously hypertensive [SHR]; obese Zucker rats [OZR]) with acute and/or chronic femoral arterial occlusion. Therapeutic efficacy was assessed by administration of Ramipril or Losartan to SHR after femoral artery excision. RESULTS VO measurement in WKY demonstrated the utility of this method to assess hind limb perfusion at rest and during calf muscle contraction. Although application to diseased models (OZR and SHR) demonstrated normal resting perfusion compared with contralateral limbs, a significant reduction in reserve capacity was uncovered with muscle stimulation. Administration of Ramipril and Losartan demonstrated significant improvement in functional arterial reserve. CONCLUSIONS The results demonstrate that this novel method to assess distal limb perfusion in small rodents with subcritical limb ischemia is sufficient to unmask perfusion deficits not apparent at rest, detect impaired compensation in diseased animal models with risk factors, and assess therapeutic efficacy. The approach provides a significant advance in methods to investigate potential mechanisms and novel therapies for subcritical limb ischemia in preclinical rodent models.
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Affiliation(s)
- Matthew A Ziegler
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Matthew R DiStasi
- Departments of Pediatrics, and Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Steven J Miller
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Michael C Dalsing
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Joseph L Unthank
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana; Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana.
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DiStasi MR, Mund JA, Bohlen HG, Miller SJ, Ingram DA, Dalsing MC, Unthank JL. Impaired compensation to femoral artery ligation in diet-induced obese mice is primarily mediated via suppression of collateral growth by Nox2 and p47phox. Am J Physiol Heart Circ Physiol 2015; 309:H1207-17. [PMID: 26297224 DOI: 10.1152/ajpheart.00180.2015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 08/20/2015] [Indexed: 02/07/2023]
Abstract
The present study was undertaken to establish the role of NADPH oxidase (Nox) in impaired vascular compensation to arterial occlusion that occurs in the presence of risk factors associated with oxidative stress. Diet-induced obese (DIO) mice characterized by multiple comorbidities including diabetes and hyperlipidemia were used as a preclinical model. Arterial occlusion was induced by distal femoral artery ligation in lean and DIO mice. Proximal collateral arteries were identified as the site of major (∼70%) vascular resistance to calf perfusion by distal arterial pressures, which decreased from ∼80 to ∼30 mmHg with ligation in both lean and DIO mice. Two weeks after ligation, significant vascular compensation occurred in lean but not DIO mice as evidenced by increased perfusion (147 ± 48% vs. 49 ± 29%) and collateral diameter (151 ± 30% vs. 44 ± 17%). Vascular mRNA expression of p22(phox), Nox2, Nox4, and p47(phox) were all increased in DIO mice. Treatment of DIO mice with either apocynin or Nox2ds-tat or with whole body ablation of either Nox2 or p47(phox) ameliorated the impairment in both collateral growth and hindlimb perfusion. Multiparametric flow cytometry analysis demonstrated elevated levels of circulating monocytes in DIO mice without impaired mobilization and demargination after femoral artery ligation. These results establish collateral resistance as the major limitation to calf perfusion in this preclinical model, demonstrate than monocyte mobilization and demarginatin is not suppressed, implicate Nox2-p47(phox) interactions in the impairment of vascular compensation to arterial occlusion in DIO mice, and suggest that selective Nox component suppression/inhibition may be effective as either primary or adjuvant therapy for claudicants.
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Affiliation(s)
- Matthew R DiStasi
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana; Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana
| | - Julie A Mund
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana; Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana
| | - H Glenn Bohlen
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Steven J Miller
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - David A Ingram
- Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana; Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, Indiana; and Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana
| | - Michael C Dalsing
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana
| | - Joseph L Unthank
- Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana; Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana;
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Moore SM, Zhang H, Maeda N, Doerschuk CM, Faber JE. Cardiovascular risk factors cause premature rarefaction of the collateral circulation and greater ischemic tissue injury. Angiogenesis 2015; 18:265-81. [PMID: 25862671 DOI: 10.1007/s10456-015-9465-6] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2014] [Accepted: 04/06/2015] [Indexed: 01/09/2023]
Abstract
RATIONALE Collaterals lessen tissue injury in occlusive disease. However, aging causes progressive decline in their number and smaller diameters in those that remain (collateral rarefaction), beginning at 16 months of age in mice (i.e., middle age), and worse ischemic injury-effects that are accelerated in even 3-month-old eNOS(-/-) mice. These findings have found indirect support in recent human studies. OBJECTIVE We sought to determine whether other cardiovascular risk factors (CVRFs) associated with endothelial dysfunction cause collateral rarefaction, investigate possible mechanisms, and test strategies for prevention. METHODS AND RESULTS Mice with nine different models of CVRFs of 4-12 months of age were assessed for number and diameter of native collaterals in skeletal muscle and brain and for collateral-dependent perfusion and ischemic injury after arterial occlusion. Hypertension caused collateral rarefaction whose severity increased with duration and level of hypertension, accompanied by greater hindlimb ischemia and cerebral infarct volume. Chronic treatment of wild-type mice with L-N (G)-nitro-arginine methylester caused similar rarefaction and worse ischemic injury which were not prevented by lowering arterial pressure with hydralazine. Metabolic syndrome, hypercholesterolemia, diabetes mellitus, and obesity also caused collateral rarefaction. Neither chronic statin treatment nor exercise training lessened hypertension-induced rarefaction. CONCLUSION Chronic CVRF presence caused collateral rarefaction and worse ischemic injury, even at relatively young ages. Rarefaction was associated with increased proliferation rate of collateral endothelial cells, effects that may promote accelerated endothelial cell senescence.
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Affiliation(s)
- Scott M Moore
- Department of Cell Biology and Physiology, 6309 MBRB, University of North Carolina, Chapel Hill, NC, 27599-7545, USA
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11
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DiStasi MR, Unthank JL, Miller SJ. Nox2 and p47(phox) modulate compensatory growth of primary collateral arteries. Am J Physiol Heart Circ Physiol 2014; 306:H1435-43. [PMID: 24633549 DOI: 10.1152/ajpheart.00828.2013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The role of NADPH oxidase (Nox) in both the promotion and impairment of compensatory collateral growth remains controversial because the specific Nox and reactive oxygen species involved are unclear. The aim of this study was to identify the primary Nox and reactive oxygen species associated with early stage compensatory collateral growth in young, healthy animals. Ligation of the feed arteries that form primary collateral pathways in rat mesentery and mouse hindlimb was used to assess the role of Nox during collateral growth. Changes in mesenteric collateral artery Nox mRNA expression determined by real-time PCR at 1, 3, and 7 days relative to same-animal control arteries suggested a role for Nox subunits Nox2 and p47(phox). Administration of apocynin or Nox2ds-tat suppressed collateral growth in both rat and mouse models, suggesting the Nox2/p47(phox) interaction was involved. Functional significance of p47(phox) expression was assessed by evaluation of collateral growth in rats administered p47(phox) small interfering RNA and in p47(phox-/-) mice. Diameter measurements of collateral mesenteric and gracilis arteries at 7 and 14 days, respectively, indicated no significant collateral growth compared with control rats or C57BL/6 mice. Chronic polyethylene glycol-conjugated catalase administration significantly suppressed collateral development in rats and mice, implying a requirement for H2O2. Taken together, these results suggest that Nox2, modulated at least in part by p47(phox), mediates early stage compensatory collateral development via a process dependent upon peroxide generation. These results have important implications for the use of antioxidants and the development of therapies for peripheral arterial disease.
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Affiliation(s)
- Matthew R DiStasi
- Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Joseph L Unthank
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana; and Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
| | - Steven J Miller
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Indiana; and Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana
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Abstract
Peripheral arterial disease (PAD) is a common vascular disease that reduces blood flow capacity to the legs of patients. PAD leads to exercise intolerance that can progress in severity to greatly limit mobility, and in advanced cases leads to frank ischemia with pain at rest. It is estimated that 12 to 15 million people in the United States are diagnosed with PAD, with a much larger population that is undiagnosed. The presence of PAD predicts a 50% to 1500% increase in morbidity and mortality, depending on severity. Treatment of patients with PAD is limited to modification of cardiovascular disease risk factors, pharmacological intervention, surgery, and exercise therapy. Extended exercise programs that involve walking approximately five times per week, at a significant intensity that requires frequent rest periods, are most significant. Preclinical studies and virtually all clinical trials demonstrate the benefits of exercise therapy, including improved walking tolerance, modified inflammatory/hemostatic markers, enhanced vasoresponsiveness, adaptations within the limb (angiogenesis, arteriogenesis, and mitochondrial synthesis) that enhance oxygen delivery and metabolic responses, potentially delayed progression of the disease, enhanced quality of life indices, and extended longevity. A synthesis is provided as to how these adaptations can develop in the context of our current state of knowledge and events known to be orchestrated by exercise. The benefits are so compelling that exercise prescription should be an essential option presented to patients with PAD in the absence of contraindications. Obviously, selecting for a lifestyle pattern that includes enhanced physical activity prior to the advance of PAD limitations is the most desirable and beneficial.
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Affiliation(s)
- Tara L Haas
- Angiogenesis Research Group, Muscle Health Research Centre, Faculty of Health, York University, Toronto, Ontario, Canada
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Abstract
Arteriosclerotic vascular disease is the most common cause of death and a major cause of disability in the developed world. Adverse outcomes of arteriosclerotic vascular disease are related to consequences of tissue ischemia and necrosis affecting the heart, brain, limbs, and other organs. Collateral artery growth or arteriogenesis occurs naturally and can help restore perfusion to ischemic tissues. Understanding the mechanisms of collateral artery growth may provide therapeutic options for patients with ischemic vascular disease. In this review, we examine the evidence for a role of monocytes and macrophages in collateral arteriogenesis.
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Affiliation(s)
- Erik Fung
- Department of Medicine, Heart and Vascular Center, Dartmouth-Hitchcock Medical CenterLebanon, NH, USA
| | - Armin Helisch
- Department of Medicine, Heart and Vascular Center, Dartmouth-Hitchcock Medical CenterLebanon, NH, USA
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15
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Hamburg NM, Balady GJ. Exercise rehabilitation in peripheral artery disease: functional impact and mechanisms of benefits. Circulation 2011; 123:87-97. [PMID: 21200015 DOI: 10.1161/circulationaha.109.881888] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Affiliation(s)
- Naomi M Hamburg
- Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston Medical Center, Boston, MA 02118, USA
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Ren Y, D'Ambrosio MA, Garvin JL, Carretero OA. Angiotensin II enhances connecting tubule glomerular feedback. Hypertension 2010; 56:636-42. [PMID: 20696981 DOI: 10.1161/hypertensionaha.110.153692] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Increasing Na delivery to epithelial Na channels (ENaCs) in the connecting tubule (CNT) causes dilation of the afferent arteriole (Af-Art), a process we call CNT glomerular feedback (CTGF). Angiotensin II (Ang II) stimulates ENaC in the collecting duct via Ang II type 1 receptors. We hypothesized that Ang II in the CNT lumen enhances CTGF by activation of Ang II type 1 receptors, protein kinase C and ENaC. Rabbit afferent arterioles and their adherent CNT were microperfused and preconstricted with norepinephrine. Each experiment involved generating 2 consecutive concentration-response curves by increasing NaCl in the CNT lumen. During the control period, the maximum dilation of the afferent arteriole was 7.9±0.4 μm, and the concentration of NaCl in the CNT needed to achieve half maximal response (EC(50)) was 34.7±5.2 mmol/L. After adding Ang II (10(-9) mol/L) to the CNT lumen, the maximal response was 9.5±0.7 μm and the EC(50) was 11.6±1.3 mmol/L (P=0.01 versus control). Losartan, an Ang II type 1 antagonist (10(-6) mol/L) blocked the stimulatory effect of Ang II; PD123319, an Ang II type 2 antagonist (10(-6) mol/L), did not. The protein kinase C inhibitor staurosporine (10(-8) mol/L) added to the CNT inhibited the stimulatory effect of Ang II. The ENaC inhibitor benzamil (10(-6) mol/L) prevented both CTGF and its stimulation by Ang II. We concluded that Ang II in the CNT lumen enhances CTGF via activation of Ang II type 1 and that this effect requires activation of protein kinase C and ENaC. Potentiation of CTGF by Ang II could help preserve glomerular filtration rate in the presence of renal vasoconstriction.
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Affiliation(s)
- Yilin Ren
- Hypertension and Vascular Research Division, Department of Internal Medicine, Henry Ford Hospital, Detroit, MI 48202, USA
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Colleran PN, Li Z, Yang HT, Laughlin MH, Terjung RL. Vasoresponsiveness of collateral vessels in the rat hindlimb: influence of training. J Physiol 2010. [PMID: 20194126 DOI: 10.1113/jphysiol.2009.18624] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Exercise training is known to be an effective means of improving functional capacity and quality of life in patients with peripheral arterial insufficiency (PAI). However, the specific training-induced physiological adaptations occurring within collateral vessels remain to be clearly defined. The purpose of this study was to determine the effect of exercise training on vasomotor properties of isolated peripheral collateral arteries. We hypothesized that daily treadmill exercise would improve the poor vasodilatory capacity of collateral arteries isolated from rats exposed to surgical occlusion of the femoral artery. Following femoral artery ligation, animals were either kept sedentary or exercise trained daily for a period of 3 weeks. Hindlimb collateral arteries were then isolated, cannulated and pressurized via hydrostatic reservoirs to an intravascular pressure of either 45 or 120 cmH(2)O. Non-occluded contralateral vessels of the sedentary animals served as normal Control. Vasodilatory responses to acetylcholine (ACh; 1 x 10(9)-1 x 10(5)m) and sodium nitroprusside (SNP; 1 x 10(9)-1 x 10(4)m), constrictor responses to phenylephrine (PE; 1 x 10(9)-1 x 10(4)m), and flow-induced vasodilatation were determined. Endothelium-mediated vasodilatation responses were significantly greater to either ACh (P < 0.02) or intravascular flow (P < 0.001) in collateral arteries of trained rats. Neither blockade of cyclooxygenase with indomethacin (Indo; 5 microm) nor blockade of endothelial nitric oxide synthase with N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microm) eliminated this ACh- or flow-induced vasodilatation. The depressed vasodilatory response to SNP caused by vascular occlusion was reversed with training. These data indicate that exercise training improves endothelium-mediated vasodilatory capacity of hindlimb collateral arteries, apparently by enhanced production of the putative endothelium-derived hyperpolarizing factor(s). If these findings were applicable to patients with PAI, they could contribute to an improved collateral vessel function and enhance exercise tolerance during routine physical activity.
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Affiliation(s)
- Patrick N Colleran
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Colleran PN, Li Z, Yang HT, Laughlin MH, Terjung RL. Vasoresponsiveness of collateral vessels in the rat hindlimb: influence of training. J Physiol 2010; 588:1293-307. [PMID: 20194126 DOI: 10.1113/jphysiol.2009.186247] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Exercise training is known to be an effective means of improving functional capacity and quality of life in patients with peripheral arterial insufficiency (PAI). However, the specific training-induced physiological adaptations occurring within collateral vessels remain to be clearly defined. The purpose of this study was to determine the effect of exercise training on vasomotor properties of isolated peripheral collateral arteries. We hypothesized that daily treadmill exercise would improve the poor vasodilatory capacity of collateral arteries isolated from rats exposed to surgical occlusion of the femoral artery. Following femoral artery ligation, animals were either kept sedentary or exercise trained daily for a period of 3 weeks. Hindlimb collateral arteries were then isolated, cannulated and pressurized via hydrostatic reservoirs to an intravascular pressure of either 45 or 120 cmH(2)O. Non-occluded contralateral vessels of the sedentary animals served as normal Control. Vasodilatory responses to acetylcholine (ACh; 1 x 10(9)-1 x 10(5)m) and sodium nitroprusside (SNP; 1 x 10(9)-1 x 10(4)m), constrictor responses to phenylephrine (PE; 1 x 10(9)-1 x 10(4)m), and flow-induced vasodilatation were determined. Endothelium-mediated vasodilatation responses were significantly greater to either ACh (P < 0.02) or intravascular flow (P < 0.001) in collateral arteries of trained rats. Neither blockade of cyclooxygenase with indomethacin (Indo; 5 microm) nor blockade of endothelial nitric oxide synthase with N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microm) eliminated this ACh- or flow-induced vasodilatation. The depressed vasodilatory response to SNP caused by vascular occlusion was reversed with training. These data indicate that exercise training improves endothelium-mediated vasodilatory capacity of hindlimb collateral arteries, apparently by enhanced production of the putative endothelium-derived hyperpolarizing factor(s). If these findings were applicable to patients with PAI, they could contribute to an improved collateral vessel function and enhance exercise tolerance during routine physical activity.
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Affiliation(s)
- Patrick N Colleran
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA
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Ziegler MA, Distasi MR, Bills RG, Miller SJ, Alloosh M, Murphy MP, Akingba AG, Sturek M, Dalsing MC, Unthank JL. Marvels, mysteries, and misconceptions of vascular compensation to peripheral artery occlusion. Microcirculation 2010; 17:3-20. [PMID: 20141596 PMCID: PMC2909670 DOI: 10.1111/j.1549-8719.2010.00008.x] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Peripheral arterial disease is a major health problem and there is a significant need to develop therapies to prevent its progression to claudication and critical limb ischemia. Promising results in rodent models of arterial occlusion have generally failed to predict clinical success and led to questions of their relevance. While sub-optimal models may have contributed to the lack of progress, we suggest that advancement has also been hindered by misconceptions of the human capacity for compensation and the specific vessels which are of primary importance. We present and summarize new and existing data from humans, Ossabaw miniature pigs, and rodents which provide compelling evidence that natural compensation to occlusion of a major artery (i) may completely restore perfusion, (ii) occurs in specific pre-existing small arteries, rather than the distal vasculature, via mechanisms involving flow-mediated dilation and remodeling (iii) is impaired by cardiovascular risk factors which suppress the flow-mediated mechanisms and (iv) can be restored by reversal of endothelial dysfunction. We propose that restoration of the capacity for flow-mediated dilation and remodeling in small arteries represents a largely unexplored potential therapeutic opportunity to enhance compensation for major arterial occlusion and prevent the progression to critical limb ischemia in the peripheral circulation.
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Affiliation(s)
- Matthew A Ziegler
- Department of Surgery, Indiana University School of Medicine, Indianapolis, IN, USA
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20
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Distasi MR, Case J, Ziegler MA, Dinauer MC, Yoder MC, Haneline LS, Dalsing MC, Miller SJ, Labarrere CA, Murphy MP, Ingram DA, Unthank JL. Suppressed hindlimb perfusion in Rac2-/- and Nox2-/- mice does not result from impaired collateral growth. Am J Physiol Heart Circ Physiol 2009; 296:H877-86. [PMID: 19151256 PMCID: PMC2660231 DOI: 10.1152/ajpheart.00772.2008] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2008] [Accepted: 01/12/2009] [Indexed: 11/22/2022]
Abstract
While tissue perfusion and angiogenesis subsequent to acute femoral artery occlusion are suppressed in NADPH oxidase 2 (Nox2)-null (Nox2(-/-)) mice, studies have not established the role of Nox2 in collateral artery enlargement. Rac2 is a small GTPase that binds Nox2 and activates Nox2-based NAD(P)H oxidase but, unlike Nox2, is primarily restricted to bone marrow-derived cells. In this study, we used Rac2-null (Rac2(-/-)) and Nox2(-/-) mice with a novel method of identifying primary hindlimb collaterals to investigate the hypothesis that collateral growth requires these molecules. When initial experiments performed with femoral ligation demonstrated similar perfusion and collateral growth in Rac2(-/-) and wild-type C57BL/6J (BL6) mice, subsequent experiments were performed with a more severe ischemia model, femoral artery excision. After femoral excision, tissue perfusion was suppressed in Rac2(-/-) mice relative to BL6 mice. Histological assessment of ischemic injury including necrotic and regenerated muscle fibers and lipid and collagen deposition demonstrated greater injury in Rac2(-/-) mice. The diameters of primary collaterals identified during Microfil injection with intravital microscopy were enlarged to a similar extent in BL6 and Rac2(-/-) mice. Intimal cells in collateral cross sections were increased in number in both strains and were CD31 positive and CD45 negative. Circulating leukocytes and CD11b(+) cells were increased more in Rac2(-/-) than BL6 animals. Experiments performed in Nox2(-/-) mice to verify that the unexpected results related to collateral growth were not unique to Rac2(-/-) mice gave equivalent results. The data demonstrate that, subsequent to acute femoral artery excision, perfusion recovery is impaired in Rac2(-/-) and Nox2(-/-) mice but that collateral luminal expansion and intimal cell recruitment/proliferation are normal. These novel results indicate that collateral luminal expansion and intimal cell recruitment/proliferation are not mediated by Rac2 and Nox2.
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Affiliation(s)
- Matthew R Distasi
- Department of Cellular and Integrative Physiology, Indiana Univ. School of Medicine, 1001 W. 10th St., WD OPW 425 E, Indianapolis, IN 46202, USA
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Taylor JC, Yang HT, Laughlin MH, Terjung RL. Alpha-adrenergic and neuropeptide Y Y1 receptor control of collateral circuit conductance: influence of exercise training. J Physiol 2008; 586:5983-98. [PMID: 18981031 DOI: 10.1113/jphysiol.2008.160101] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study evaluated the role of alpha-adrenergic receptor- and neuropeptide Y (NPY) Y1 receptor-mediated vasoconstriction in the collateral circuit of the hind limb. Animals were evaluated either the same day (Acute) or 3 weeks following occlusion of the femoral artery; the 3-week animals were in turn limited to cage activity (Sed) or given daily exercise (Trained). Collateral-dependent blood flows (BFs) were measured during exercise with microspheres before and after alpha-receptor inhibition (phentolamine) and then NPY Y1 receptor inhibition (BIBP 3226) at the same running speed. Blood pressures (BPs) were measured above (caudal artery) and below (distal femoral artery) the collateral circuit. Arterial BPs were reduced by alpha-inhibition (50-60 mmHg) to approximately 75 mmHg, but not further by NPY Y1 receptor inhibition. Effective experimental sympatholysis was verified by 50-100% increases (P < 0.001) in conductance of active muscles not affected by femoral occlusion with receptor inhibition. In the absence of receptor inhibition, vascular conductance of the collateral circuit was minimal in the Acute group (0.13 +/- 0.02), increased over time in the Sed group (0.41 +/- 0.03; P < 0.001), and increased further in the Trained group (0.53 +/- 0.03; P < 0.02). Combined receptor inhibition increased collateral circuit conductances (P < 0.005), most in the Acute group (116 +/- 37%; P < 0.02), as compared to the Sed (41 +/- 6.6%; P < 0.001) and Trained (31 +/- 5.6%; P < 0.001) groups. Thus, while the sympathetic influence of the collateral circuit remained in the Sed and Trained animals, it became less influential with time post-occlusion. Collateral conductances were collectively greater (P < 0.01) in the Trained as compared to Sed group, irrespective of the presence or absence of receptor inhibition. Conductances of the active ischaemic calf muscle, with combined receptor inhibition, were suboptimal in the Acute group, but increased in Sed and Trained animals to exceptionally high values (e.g. red fibre section of the gastrocnemius: approximately 7 ml min(-1) (100 g)(-1) mmHg(-1)). Thus, occlusion of the femoral artery promulgated vascular adaptations, even in vessels that are not part of the collateral circuit. The presence of active sympathetic control of the collateral circuit, even with exercise training, raises the potential for reductions in collateral BF below that possible by the structure of the collateral circuit. However, even with release of this sympathetic vasoconstriction, conductance of the collateral circuit was significantly greater with exercise training, probably due to the network of structurally larger collateral vessels.
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Affiliation(s)
- Jessica C Taylor
- Department of Biomedical Sciences, E102 Vet. Medical Bldg, University of Missouri, Columbia, MO 65211, USA
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van Golde JM, Ruiter MS, Schaper NC, Vöö S, Waltenberger J, Backes WH, Post MJ, Huijberts MS. Impaired collateral recruitment and outward remodeling in experimental diabetes. Diabetes 2008; 57:2818-23. [PMID: 18633114 PMCID: PMC2551694 DOI: 10.2337/db08-0229] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2008] [Accepted: 07/01/2008] [Indexed: 12/14/2022]
Abstract
OBJECTIVE In this study, the effect of chronic hyperglycemia on acute ligation-induced collateral vasodilation, on monocyte chemotaxis, and on structural outward remodeling of collaterals was investigated. RESEARCH DESIGN AND METHODS Femoral artery ligation was performed 8 weeks after alloxan or saline treatment in New Zealand White rabbits. Angiography was performed directly, 1 and 3 weeks after ligation. These angiographic recordings were used to quantify number of collaterals, lumen, and blood volume index. Reactive hyperemia response was tested by intramuscular laser Doppler measurements. Subsequently, blood was sampled from the aorta for monocyte chemotaxis. RESULTS Ligation resulted in markedly lower acute collateral vasodilation in diabetic compared with control rabbits. Also, hyperemic vasodilatory response to local ischemia was impaired in diabetic rabbits. This difference persisted at 1 and 3 weeks after ligation, with a lower number of visible collaterals. In addition, the collateral lumen was markedly lower in diabetic rabbits after the maturation phase. Likewise, a reduced blood volume index in the region of growing collaterals was observed in diabetic animals. The monocyte migration toward vascular endothelial growth factor-A and monocyte chemotactic protein-1 was strongly reduced in diabetic rabbits. CONCLUSIONS This study demonstrates that chronic hyperglycemia negatively affects the different phases of arteriogenesis: 1) impaired shear induced vasodilatation; 2) impaired outward collateral growth, reflected in the number of collaterals and blood volume index; and 3) inhibition of monocyte chemotaxis. Impairments were most evident in the acute phase of arteriogenesis. Therapies aimed at restoring acute collateral recruitment, such as vasodilators, may be of interest to improve collateral function in diabetes.
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Affiliation(s)
- Jolanda M van Golde
- Department of Internal Medicine, Division of Endocrinology, Maastricht University Medical Centre and Cardiovascular Research Institute Maastricht, Maastricht, the Netherlands.
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Taylor JC, Li Z, Yang HT, Laughlin MH, Terjung RL. Alpha-adrenergic inhibition increases collateral circuit conductance in rats following acute occlusion of the femoral artery. J Physiol 2008; 586:1649-67. [PMID: 18218679 DOI: 10.1113/jphysiol.2007.149567] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
This study evaluated whether alpha-adrenergic activation contributes to collateral circuit vascular resistance in the hindlimb following acute unilateral occlusion of the femoral artery in rats. Blood pressures (BPs) were measured above (caudal artery) and below (distal femoral artery) the collateral circuit. Arterial BPs were reduced (15-35 mmHg) with individual (prazosin, rauwolscine) or combined (phentolamine) alpha-receptor inhibition. Blood flows (BFs) were measured using microspheres before and after alpha inhibition during the same treadmill speed. alpha(1) inhibition increased blood flow by approximately 40% to active muscles that were not affected by femoral occlusion, whereas collateral-dependent BFs to the calf muscles were reduced by 29 +/- 8.4% (P < 0.05), due to a decrease in muscle conductance with no change in collateral circuit conductance. alpha(2) inhibition decreased both collateral circuit (39 +/- 6.0%; P < 0.05) and calf muscle conductance (36 +/- 7.3%; P < 0.05), probably due to residual alpha(1) activation, since renal BF was markedly reduced with rauwolscine. Most importantly, inhibiting alpha(2) receptors in the presence of alpha(1) inhibition increased (43 +/- 12%; P < 0.05) collateral circuit conductance. Similarly, non-selective alpha inhibition with phentolamine increased collateral conductance (242 +/- 59%; P < 0.05). We interpret these findings to indicate that both alpha(1)- and alpha(2)-receptor activation can influence collateral circuit resistance in vivo during the high flow demands caused by exercise. Furthermore, we observed a reduced maximal conductances of active muscles that were ischaemic. Our findings imply that in the presence of excessive sympathetic activation, which can occur in the condition of intermittent claudication during exertion, an exaggerated vasoconstriction of the existing collateral circuit and active muscle will occur.
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Affiliation(s)
- Jessica C Taylor
- Department of Biomedical Sciences, E102 Vet. Medical Bldg, University of Missouri, Columbia, MO 65211, USA
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Sheridan KM, Ferguson MJ, Distasi MR, Witzmann FA, Dalsing MC, Miller SJ, Unthank JL. Impact of genetic background and aging on mesenteric collateral growth capacity in Fischer 344, Brown Norway, and Fischer 344 x Brown Norway hybrid rats. Am J Physiol Heart Circ Physiol 2007; 293:H3498-505. [PMID: 17906115 PMCID: PMC2859438 DOI: 10.1152/ajpheart.00040.2007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Available studies indicate that both genetic background and aging influence collateral growth capacity, but it is not known how their combination affects collateral growth. We evaluated collateral growth induced by ileal artery ligation in Fischer 344 (F344), Brown Norway (BN), and the first generation hybrid of F344 x BN (F1) rats available for aging research from the National Institute on Aging. Collateral growth was determined by paired diameter measurements in anesthetized rats immediately and 7 days postligation. In 3-mo-old rats, significant collateral growth occurred only in BN (35% +/- 11%, P < 0.001). The endothelial cell number in arterial cross sections was also determined, since this precedes shear-mediated luminal expansion. When compared with the same animal controls, the intimal cell number was increased only in BN rats (92% +/- 21%, P < 0.001). The increase in intimal cell number and the degree of collateral luminal expansion in BN rats was not affected by age from 3 to 24 mo. Immunohistochemical studies demonstrated that intimal cell proliferation was much greater in the collaterals of BN than of F1 rats. The remarkable difference between these three strains of rats used in aging research and the lack of an age-related impairment in the BN rats are novel observations. These rat strains mimic clinical observations of interindividual variation in collateral growth capacity and the impact of age on arteriogenesis and should be useful models to investigate the molecular mechanisms responsible for such differences.
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Affiliation(s)
- Kevin M Sheridan
- Department of Surgery, Indiana University School of Medicine, University Medical Center, 1001 W. 10th Street, Indianapolis, IN 46202-2879, USA
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Miller SJ, Norton LE, Murphy MP, Dalsing MC, Unthank JL. The role of the renin-angiotensin system and oxidative stress in spontaneously hypertensive rat mesenteric collateral growth impairment. Am J Physiol Heart Circ Physiol 2007; 292:H2523-31. [PMID: 17277018 DOI: 10.1152/ajpheart.01296.2006] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Recent clinical and animal studies have shown that collateral artery growth is impaired in the presence of vascular risk factors, including hypertension. Available evidence suggests that angiotensin-converting enzyme inhibitors (ACEI) promote collateral growth in both hypertensive humans and animals; however, the specific mechanisms are not established. This study evaluated the hypothesis that collateral growth impairment in hypertension is mediated by excess superoxide produced by NAD(P)H oxidase in response to stimulation of the ANG II type 1 receptor. After ileal artery ligation, mesenteric collateral growth did not occur in untreated, young, spontaneously hypertensive rats. Significant luminal expansion occurred in collaterals of spontaneously hypertensive rats treated with the superoxide dismutase mimetic tempol, the NAD(P)H oxidase inhibitor apocynin, and the ACEI captopril, but not ANG II type 1 (losartan) or type 2 (PD-123319) receptor blockers. The ACEI enalapril produced equivalent reduction of arterial pressure as captopril but did not promote luminal expansion. This suggests the effects of captopril on collateral growth might result from its antioxidant properties. RT-PCR demonstrated that ANG II type 1 receptor and angiotensinogen expression was reduced in collaterals of untreated rats. This local suppression of the renin angiotensin system provides a potential explanation for the lack of effect of enalapril and losartan on collateral growth. The results demonstrate the capability of antioxidant therapies, including captopril, to reverse impaired collateral artery growth and the novel finding that components of the local renin angiotensin system are naturally suppressed in collaterals.
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Affiliation(s)
- Steven J Miller
- Department of Surgery, Indiana University Medical Center, 1001 West Tenth Street, Indianapolis, IN 46202-2879, USA
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Laughlin MH, Cook JD, Tremble R, Ingram D, Colleran PN, Turk JR. Exercise training produces nonuniform increases in arteriolar density of rat soleus and gastrocnemius muscle. Microcirculation 2006; 13:175-86. [PMID: 16627360 PMCID: PMC2646594 DOI: 10.1080/10739680600556829] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
OBJECTIVE Exercise training has been shown to increase regional blood flow capacity to muscle tissue containing fibers that experience increased activity during exercise. The purpose of this study was to test the hypothesis that the increased blood flow capacity is partially the result of increases in arteriolar density (number of arterioles/mm2 of tissue), specifically in skeletal muscle tissue, with the largest relative increase in muscle fiber activity during training bouts. METHODS This hypothesis was tested by comparing and contrasting the effects of endurance exercise training (ET) and interval sprint training (IST) on arteriolar density in soleus muscle (S) red (Gr) and white (Gw) portions of gastrocnemius muscle of male Sprague Dawley rats. ET rats completed 10 weeks of treadmill training 30 m/min, 15% grade, 60 min/day, 5 days/week, while IST rats completed 10 weeks of IST consisting of six 2.5-min exercise bouts, with 4.5-min rest between bouts (60 m/min, 15% incline), 5 days/week. The hypothesis would be supported if ET increased arteriolar density in S and Gr and if IST increased arteriolar density in Gw. RESULTS ET increased arteriolar density above values of sedentary rats (SED) in both the Gw (ET = 0.93 +/- 0.19 arterioles/microm2; SED = 0.44 +/- 0.09 arterioles/microm2) and Gr (ET = 0.97 +/- 0.1 arterioles/microm2; SED = 0.51 +/- 0.06 arterioles/microm2) muscles, but not in S (ET = 1.69 +/- 0.45 arterioles/microm2; SED = 1.51 +/- 0.34 arterioles/microm2) muscle. In contrast, IST did not alter arteriolar density in Gw or Gr muscle tissue. Although arterial wall thickness was greater in S (3.95 +/- 0.40 microm) and Gr (6.24 +/- 0.59 microm) than Gw (2.76 +/- 0.18 microm), neither ET or IST altered mean wall thickness in either muscle. CONCLUSION Increases in blood flow capacity produced in Gr and Gw by ET appear to be due in part to increased arteriolar density. In contrast, increased arteriolar density does not contribute to increased blood flow capacity of Gw in IST rats.
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Affiliation(s)
- M Harold Laughlin
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211, USA.
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Helisch A, Wagner S, Khan N, Drinane M, Wolfram S, Heil M, Ziegelhoeffer T, Brandt U, Pearlman JD, Swartz HM, Schaper W. Impact of Mouse Strain Differences in Innate Hindlimb Collateral Vasculature. Arterioscler Thromb Vasc Biol 2006; 26:520-6. [PMID: 16397137 DOI: 10.1161/01.atv.0000202677.55012.a0] [Citation(s) in RCA: 175] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Objective—
To assess the importance of genetic background for collateral artery development.
Methods and Results—
C57BL/6, BALB/c and 129S2/Sv mice were studied after femoral artery ligation by laser Doppler imaging, visible light oximetry, time-of-flight–magnetic resonance imaging, and treadmill testing; C57BL/6 and BALB/c also underwent electron paramagnetic resonance (EPR) oximetry, x-ray angiography, and histology. C57BL/6 had the least initial distal ischemia and most complete recovery. BALB/c had the most severe initial ischemia and poorest recovery. BALB/c had some vasodilatory reserve in their ligated limbs not seen in the other strains at 3 weeks. By in vivo TOF-magnetic resonance angiography, C57BL/6 had larger preexistent and developed collaterals. By x-ray angiography, C57BL/6 had a higher collateral-dependent filling score and number of visible collaterals immediately after femoral ligation and a higher number of visible collaterals at 1 week but not at 4 weeks. EPR oximetry and histology revealed hypoxia and tissue damage in regions of collateral growth of BALB/c but not C57BL/6 mice. In C57BL/6 BrdUrd uptake in the thigh was limited to larger vessels and isolated perivascular cells. Proliferative activity in collateral arterioles was similar in both strains.
Conclusions—
Genetic differences in preexistent collateral vasculature can profoundly affect outcome and milieu for compensatory collateral artery growth after femoral artery occlusion.
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Affiliation(s)
- Armin Helisch
- Department of Experimental Cardiology, Max-Planck-Institute for Physiological & Clinical Research, Bad Nauheim, Germany.
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Lloyd PG, Prior BM, Li H, Yang HT, Terjung RL. VEGF receptor antagonism blocks arteriogenesis, but only partially inhibits angiogenesis, in skeletal muscle of exercise-trained rats. Am J Physiol Heart Circ Physiol 2005; 288:H759-68. [PMID: 15471974 DOI: 10.1152/ajpheart.00786.2004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Both collateral vessel enlargement (arteriogenesis) and capillary growth (angiogenesis) in skeletal muscle occur in response to exercise training. Vascular endothelial growth factor (VEGF) is implicated in both processes. Thus we examined the effect of a VEGF receptor (VEGF-R) inhibitor (ZD4190, AstraZeneca) on collateral-dependent blood flow in vivo and collateral artery size ex vivo (indicators of arteriogenesis) and capillary contacts per fiber (CCF; an index of angiogenesis) in skeletal muscle of both sedentary and exercise-trained rats 14 days after bilateral occlusion of the femoral arteries. Total daily treadmill run time increased appreciably from ∼70 to ∼100 min (at 15–20 m/min, twice per day) and produced a large (∼75%, P < 0.01) increase in calf muscle blood flow and a greater size of the collateral artery (wall cross-sectional area). ZD4190, which previously has been shown to inhibit the activity of VEGF-R2 and -R1 tyrosine kinase in vitro (IC50 = 30 and 700 nM, respectively), completely blocked the increase in collateral-dependent blood flow and inhibited collateral vessel enlargement. Thus exercise-stimulated collateral arteriogenesis appears to be completely dependent on VEGF-R signaling. Interestingly, enhanced mRNA expression of the VEGF family ligand placental growth factor (2- to 3.5-fold), VEGF-R1 (∼2-fold), and endothelial nitric oxide synthase (2- to 3.5-fold) in an isolated collateral artery implicates these factors as important in arteriogenesis. Training of ischemic muscle also induced angiogenesis, as shown by an increase (∼25%, P < 0.01) in CCF in white gastrocnemius muscle. VEGF-R inhibition only partially blocked ( P < 0.01) but did not eliminate the increase ( P < 0.01) in capillarity. Our findings indicate that VEGF-R tyrosine kinase activity is essential for collateral arteriogenesis and important for the angiogenesis induced in ischemic muscle by exercise training; however, other angiogenic stimuli are also important for angiogenesis in flow-limited active muscle.
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Affiliation(s)
- Pamela G Lloyd
- Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, Missouri 65211, USA
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Affiliation(s)
- Matthias Heil
- Max-Planck-Institute for Physiological and Clinical Research, Department of Experimental Cardiology, Benekestrasse 2, 61231 Bad Nauheim, Germany.
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Sindermann JR, March KL. Balancing luminal size and smooth muscle proliferation--a key control point in atherosclerosis and arteriogenesis. EXS 2004:193-205. [PMID: 15617480 DOI: 10.1007/3-7643-7311-3_14] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/07/2023]
Affiliation(s)
- Jürgen R Sindermann
- Department of Cardiology and Angiology, Institute for Arteriosclerosis Research, University of Münster Albert-Schweitzer-Strasse 33, 48149 Münster, Germany.
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Ultrasound energy improves myocardial perfusion in the presence of coronary occlusion. J Am Coll Cardiol 2004; 44:1454-8. [PMID: 15464327 DOI: 10.1016/j.jacc.2004.06.062] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2004] [Revised: 04/21/2004] [Accepted: 06/21/2004] [Indexed: 11/23/2022]
Abstract
OBJECTIVES We evaluated whether ultrasound improves myocardial tissue perfusion in 14 animals with coronary artery occlusion. BACKGROUND A recent study demonstrated that low-frequency ultrasound improves tissue perfusion in the rabbit ischemic limb, but there are no data on ultrasound enhancement of myocardial perfusion. METHODS Fourteen animals (9 dogs, 5 pigs) underwent thoracotomy and occlusion of a diagonal branch of the left anterior descending coronary artery. Myocardial tissue perfusion units (TPUs) and pH were measured before coronary occlusion, after occlusion, and after direct exposure of the ischemic myocardium in the presence of fixed occlusion to low-frequency ultrasound (27 kHz). RESULTS The TPU decreased from 100.9 +/- 13 at baseline to 71.1 +/- 13 (p < 0.01) after 60 min occlusion but rose by 19.7% to 85.1 +/- 8 (p < 0.01) after ultrasound exposure for 60 min. After 60-min coronary occlusion, myocardial pH fell from 7.43 +/- 14 to 7.05 +/- 0.15 (p < 0.01) but then improved to normal (7.46 +/- 0.32) after ultrasound for 60 min. Administration of L-Nomega-nitro-arginine methyl esther (L-NAME), an inhibitor of nitric oxide synthase, before ultrasound exposure, blocked improvement in myocardial tissue perfusion and pH by ultrasound. Quantitative histomorphology showed a significant increase in the capillary area of myocardium exposed to ultrasound versus non-exposed myocardium (16.2 +/- 7.9 vs. 8.2 +/- 2.1, p < 0.02). CONCLUSIONS Low-frequency, low-intensity ultrasound improves myocardial tissue perfusion and pH in the presence of a fixed coronary artery occlusion.
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Prior BM, Lloyd PG, Ren J, Li H, Yang HT, Laughlin MH, Terjung RL. Time course of changes in collateral blood flow and isolated vessel size and gene expression after femoral artery occlusion in rats. Am J Physiol Heart Circ Physiol 2004; 287:H2434-47. [PMID: 15271665 DOI: 10.1152/ajpheart.00398.2004] [Citation(s) in RCA: 82] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The objectives of this study were to assess the time course of enlargement and gene expression of a collateral vessel that enlarges following occlusion of the femoral artery and to relate these responses to the increases in collateral-dependent blood flow to the calf muscles in vivo. We employed exercise training to stimulate collateral vessel development. Rats were exercise trained or kept sedentary for various times of up to 25 days postbilateral occlusion (n=approximately 9/time point). Collateral blood flow to the calf muscles, determined with microspheres, increased modestly over the first few days to approximately 40 ml.min(-1).100 g(-1) in sedentary animals; the increase continued over time to approximately 80 ml.min(-1).100 g(-1) in the trained animals. Diameters of the isolated collateral vessels increased progressively over time, whereas an increased vessel compliance observed at low pressures was similar across time. These responses were greater in the trained animals. The time course of upregulation of vascular endothelial growth factor and placental growth factor, and particularly endothelial nitric oxide synthase and fms-like tyrosine kinase 1, mRNAs in the isolated collateral vessel implicates these factors as integral to the arteriogenic process. Collateral vessel enlargement and increased compliance at low pressures contribute to the enlarged circuit available for collateral blood flow. However, modulation of the functioning collateral vessel diameter, by smooth muscle tone, must occur to account for the observed increases in collateral blood flow measured in vivo.
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Affiliation(s)
- Barry M Prior
- Biomedical Sciences, E102 Vet Med Bldg., Univ. of Missouri, Columbia, MO 65211, USA
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Waters RE, Terjung RL, Peters KG, Annex BH. Preclinical models of human peripheral arterial occlusive disease: implications for investigation of therapeutic agents. J Appl Physiol (1985) 2004; 97:773-80. [PMID: 15107408 DOI: 10.1152/japplphysiol.00107.2004] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peripheral arterial occlusive disease (PAOD) is now recognized as a combination of clinical syndromes that are associated with significant morbidity and mortality. The primary pathophysiology of PAOD is impaired perfusion to the lower extremity. Effective pharmacotherapy designed to increase perfusion in PAOD is lacking, and revascularization options are suboptimal. New and more efficacious therapies that improve blood flow are definitely needed, and thus designing, describing, and validating these new therapies in preclinical PAOD models will be essential. This study describes the various preclinical PAOD models presently in use, correlates the models to human PAOD, and reviews the available end points that can be used to detect a response to therapy.
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Affiliation(s)
- Richard E Waters
- Division of Cardiology, Department of Medicine, Durham Veterans Affairs and Duke University Medical Center, Durham, NC 27705, USA
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Liu R, Persson AEG. Angiotensin II Stimulates Calcium and Nitric Oxide Release From Macula Densa Cells Through AT1Receptors. Hypertension 2004; 43:649-53. [PMID: 14744924 DOI: 10.1161/01.hyp.0000116222.57000.85] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A fluorescent nitric oxide (NO) indicator, 4,5-diaminofluorescein diacetate, and the calcium indicator, indo-1, with 488 nm and 364 nm UV confocal laser scanning microscopy were used to detect NO and calcium concentration in rabbit macula densa (MD) cells challenged by angiotensin II (Ang II). Glomeruli with attached thick ascending limbs with the MD plaque were isolated and perfused. Ang II concentration from 10(-9) to 10(-5) progressively increased MD cell calcium and NO to peak values at 10(-6) and 10(-7), respectively. Ang II (10(-6) M) caused the cytosolic calcium concentration ([Ca(2+)](i)) to increase by 125.8+/-16.3 nM (n=17) from the bath and by 52.3+/-11.5 nM (n=18) from the lumen. AT(1) antagonist CV-11974 (10(-6) M) blocked the Ang II-induced calcium responses from bath and lumen, but AT(2) antagonist PD-123319 (10(-6) M) did not. AT(2) agonist CGP-42112A (10(-6) M) did not affect [Ca(2+)](i) in MD cells from either side. Ang II (10(-6) M) increased the NO production by 16%+/-3.4% (n=26) from the bath and by 18%+/-3.1% (n=24) from the lumen. CV-11974 (10(-6) M) blocked the NO responses from both sides, but PD-123319 (10(-6) M) did not on either side. CGP-42112A (10(-6) M) had no effect on NO in MD cells. In calcium-free experiments there was no difference from the result in normal calcium solutions. In conclusion, we found that Ang II increased [Ca(2+)](i) and stimulated NO production in MD cells from the basolateral and luminal sides through AT(1) receptors.
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Affiliation(s)
- Ruisheng Liu
- Department of Medical Cell Biology, Uppsala University, BMC Box 571, S-75123 Uppsala, Sweden.
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Srivastava S, Terjung RL, Yang HT. Basic fibroblast growth factor increases collateral blood flow in spontaneously hypertensive rats. Am J Physiol Heart Circ Physiol 2003; 285:H1190-7. [PMID: 12763749 DOI: 10.1152/ajpheart.00280.2003] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Ischemia-induced angiogenic response is reduced in spontaneously hypertensive rats (SHR). To study whether exogenous basic fibroblast growth factor (bFGF) infusion is effective in expanding collateral circulation in frankly hypertensive SHR, femoral arteries of male SHR (weighing approximately 250 g) were kept intact (nonoccluded control; n = 9) or occluded for 4h(n = 12) or for 16 days with vehicle (n = 14) or bFGF [0.5 (n = 17), 5.0 (n = 13), and 50.0 (n = 14) microg. kg-1. day-1 for 14 days] intraarterially. Maximal collateral-dependent blood flows (BF) to the hindlimbs were determined with 85Sr- and 141Ce-labeled microspheres during running at 20 and 25 m/min (15% grade). Preexercise heart rates (approximately 530 beats/min) and blood pressures (BP; approximately 200 mmHg) were similar across groups except in the high-dose bFGF group, where BP was reduced by approximately 12% (P < 0.05). Femoral artery occlusion for 4 h resulted in approximately 95% reduction of BF in calf muscles [199 +/- 18.7 (nonoccluded group) to 10 +/- 1.0 ml. min-1. 100 g-1; P < 0.001]. BF to calf muscles of the vehicle and low-dose bFGF (0.5 microg. kg-1. day-1) groups increased to 36 +/- 3.2 and 45 +/- 2.0 ml. min-1. 100 g-1, respectively (P < 0.001). bFGF infusion at 5.0 and 50.0 microg. kg-1. day-1 further increased (P < 0.001) BF to calf muscles (62 +/- 4.6 and 62 +/- 2.2 ml. min-1. 100 g-1, respectively). Our results show that bFGF can effectively increase BF in hypertensive rats. The reduced hypertension with high-dose bFGF suggests that a critical signal in arteriogenesis (nitric oxide bioavailability) may be restored. These findings suggest that the dulled endothelial nitric oxide synthase of SHR does not preempt collateral vessel remodeling.
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Affiliation(s)
- Sunita Srivastava
- Section of Vascular Surgery, University of Michigan, Ann Arbor, MI 48109, USA
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