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Ladthavorlaphatt K, Surti FBS, Beishon LC, Robinson TG, Panerai RB. Depression of dynamic cerebral autoregulation during neural activation: The role of responders and non-responders. J Cereb Blood Flow Metab 2024; 44:1231-1245. [PMID: 38301726 PMCID: PMC11179612 DOI: 10.1177/0271678x241229908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/15/2023] [Accepted: 12/28/2023] [Indexed: 02/03/2024]
Abstract
Neurovascular coupling (NVC) interaction with dynamic cerebral autoregulation (dCA) remains unclear. We investigated the effect of task complexity and duration on the interaction with dCA. Sixteen healthy participants (31.6 ± 11.6 years) performed verbal fluency (naming-words (NW)) and serial subtraction (SS) paradigms, of varying complexity, at durations of 05, 30 and 60 s. The autoregulation index (ARI), was estimated from the bilateral middle cerebral artery blood velocity (MCAv) step response, calculated by transfer function analysis (TFA), for each paradigm during unstimulated (2 min) and neuroactivated (1 min) segments. Intraclass correlation (ICC) and coefficient of variation (CV) determined reproducibility for two visits and objective criteria were applied to classify responders (R) and non-responders (NoR) to task-induced MCAv increase. ICC values demonstrated fair reproducibility in all tasks. ARI decreased in right (RH) and left (LH) hemispheres, irrespective of paradigm complexity and duration (p < 0.0001). Bilateral ARI estimates were significantly decreased during NW for the R group only (p < 0.0001) but were reduced in both R (p < 0.0001) and NoR (p = 0.03) groups for SS tasks compared with baseline. The reproducible attenuation of dCA efficiency due to paradigm-induced NVC response, its interaction, and different behaviour in R and NoR, warrant further research in different physiological and clinical conditions.
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Affiliation(s)
- Kannaphob Ladthavorlaphatt
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- Medical Diagnostics Unit, Thammasat University Hospital, Thammasat University, Pathum Thani, Thailand
- Thammasat University Centre of Excellence in Computational Mechanics and Medical Engineering, Thammasat University, Pathum Thani, Thailand
| | - Farhaana BS Surti
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
| | - Lucy C Beishon
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Thompson G Robinson
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, UK
- NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, UK
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2
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Jensen LJ. Functional, Structural and Proteomic Effects of Ageing in Resistance Arteries. Int J Mol Sci 2024; 25:2601. [PMID: 38473847 DOI: 10.3390/ijms25052601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Revised: 02/18/2024] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
The normal ageing process affects resistance arteries, leading to various functional and structural changes. Systolic hypertension is a common occurrence in human ageing, and it is associated with large artery stiffening, heightened pulsatility, small artery remodeling, and damage to critical microvascular structures. Starting from young adulthood, a progressive elevation in the mean arterial pressure is evidenced by clinical and epidemiological data as well as findings from animal models. The myogenic response, a protective mechanism for the microcirculation, may face disruptions during ageing. The dysregulation of calcium entry channels (L-type, T-type, and TRP channels), dysfunction in intracellular calcium storage and extrusion mechanisms, altered expression of potassium channels, and a change in smooth muscle calcium sensitization may contribute to the age-related dysregulation of myogenic tone. Flow-mediated vasodilation, a hallmark of endothelial function, is compromised in ageing. This endothelial dysfunction is related to increased oxidative stress, lower nitric oxide bioavailability, and a low-grade inflammatory response, further exacerbating vascular dysfunction. Resistance artery remodeling in ageing emerges as a hypertrophic response of the vessel wall that is typically observed in conjunction with outward remodeling (in normotension), or as inward hypertrophic remodeling (in hypertension). The remodeling process involves oxidative stress, inflammation, reorganization of actin cytoskeletal components, and extracellular matrix fiber proteins. Reactive oxygen species (ROS) signaling and chronic low-grade inflammation play substantial roles in age-related vascular dysfunction. Due to its role in the regulation of vascular tone and structural proteins, the RhoA/Rho-kinase pathway is an important target in age-related vascular dysfunction and diseases. Understanding the intricate interplay of these factors is crucial for developing targeted interventions to mitigate the consequences of ageing on resistance arteries and enhance the overall vascular health.
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Affiliation(s)
- Lars Jørn Jensen
- Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-1870 Frederiksberg C, Denmark
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3
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Sporkova A, Nahar T, Cao M, Ghosh S, Sens-Albert C, Friede PAP, Nagel A, Al-Hasani J, Hecker M. Characterisation of Lipoma-Preferred Partner as a Novel Mechanotransducer in Vascular Smooth Muscle Cells. Cells 2023; 12:2315. [PMID: 37759537 PMCID: PMC10529303 DOI: 10.3390/cells12182315] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/29/2023] [Accepted: 09/15/2023] [Indexed: 09/29/2023] Open
Abstract
In arteries and arterioles, a chronic increase in blood pressure raises wall tension. This continuous biomechanical strain causes a change in gene expression in vascular smooth muscle cells (VSMCs) that may lead to pathological changes. Here we have characterised the functional properties of lipoma-preferred partner (LPP), a Lin11-Isl1-Mec3 (LIM)-domain protein, which is most closely related to the mechanotransducer zyxin but selectively expressed by smooth muscle cells, including VSMCs in adult mice. VSMCs isolated from the aorta of LPP knockout (LPP-KO) mice displayed a higher rate of proliferation than their wildtype (WT) counterparts, and when cultured as three-dimensional spheroids, they revealed a higher expression of the proliferation marker Ki 67 and showed greater invasion into a collagen gel. Accordingly, the gelatinase activity was increased in LPP-KO but not WT spheroids. The LPP-KO spheroids adhering to the collagen gel responded with decreased contraction to potassium chloride. The relaxation response to caffeine and norepinephrine was also smaller in the LPP-KO spheroids than in their WT counterparts. The overexpression of zyxin in LPP-KO VSMCs resulted in a reversal to a more quiescent differentiated phenotype. In native VSMCs, i.e., in isolated perfused segments of the mesenteric artery (MA), the contractile responses of LPP-KO segments to potassium chloride, phenylephrine or endothelin-1 did not vary from those in isolated perfused WT segments. In contrast, the myogenic response of LPP-KO MA segments was significantly attenuated while zyxin-deficient MA segments displayed a normal myogenic response. We propose that LPP, which we found to be expressed solely in the medial layer of different arteries from adult mice, may play an important role in controlling the quiescent contractile phenotype of VSMCs.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Markus Hecker
- Department of Cardiovascular Physiology, Heidelberg University, Im Neuenheimer Feld 326, 69120 Heidelberg, Germany; (A.S.)
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Cui Y, Gollasch M, Kassmann M. Arterial myogenic response and aging. Ageing Res Rev 2023; 84:101813. [PMID: 36470339 DOI: 10.1016/j.arr.2022.101813] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 11/21/2022] [Accepted: 11/29/2022] [Indexed: 12/12/2022]
Abstract
The arterial myogenic response is an inherent property of resistance arteries. Myogenic tone is crucial for maintaining a relatively constant blood flow in response to changes in intraluminal pressure and protects delicate organs from excessive blood flow. Although this fundamental physiological phenomenon has been extensively studied, the underlying molecular mechanisms are largely unknown. Recent studies identified a crucial role of mechano-activated angiotensin II type 1 receptors (AT1R) in this process. The development of myogenic response is affected by aging. In this review, we summarize recent progress made to understand the role of AT1R and other mechanosensors in the control of arterial myogenic response. We discuss age-related alterations in myogenic response and possible underlying mechanisms and implications for healthy aging.
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Affiliation(s)
- Yingqiu Cui
- Charité - Universitätsmedizin Berlin, Experimental and Clinical Research Center (ECRC), a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine (MDC), Lindenberger Weg 80, 13125 Berlin, Germany
| | - Maik Gollasch
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Felix-Hausdorff-Straße 3, 17487 Greifswald, Germany
| | - Mario Kassmann
- Department of Internal Medicine and Geriatrics, University Medicine Greifswald, Felix-Hausdorff-Straße 3, 17487 Greifswald, Germany.
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5
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Wang X, Kuban-Johnston D, Lapuerta P, Lacerda CMR. Telotristat ethyl reverses myxomatous changes in mice mitral valves. Front Cardiovasc Med 2022; 9:945672. [PMID: 35990981 PMCID: PMC9386075 DOI: 10.3389/fcvm.2022.945672] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Accepted: 07/06/2022] [Indexed: 11/29/2022] Open
Abstract
Rationale Myxomatous mitral valve degeneration is a common pathological manifestation of mitral valve regurgitation, with or without valvular prolapse. In addition to similarities between naturally occurring and serotonergic valve degeneration, an increasing body of evidence has recently suggested that serotonin signaling is a regulator of degenerative valvulopathies. Studies have found that serotonin can be synthesized locally by valvular cells and serotonin receptors in turn may be activated to promote signaling. Recently, telotristat ethyl (TE) has been introduced as a treatment for carcinoid disease, by selectively inhibiting tryptophan hydroxylase 1, the rate-limiting enzyme in peripheral serotonin synthesis. TE provides a unique tool to test inhibition of serotonin synthesis in vivo, without impacting brain serotonin, to further confirm the role of local serotonin synthesis on heart valves. Objective To confirm the link between serotonin and myxomatous valvular disease in vivo. Methods and results A hypertension-induced myxomatous mitral valve disease mouse model was employed to test the effect of TE on valvular degeneration. Circulating serotonin and local serotonin in valve tissues were tested by enzyme immunoassay and immunohistochemistry, respectively. TE was administrated in two modes: (1) parallel with angiotensin II (A2); (2) post A2 treatment. Myxomatous changes were successfully recapitulated in hypertensive mice, as determined by ECM remodeling, myofibroblast transformation, and serotonin signaling activation. These changes were at least partially reversed upon TE administration. Conclusion This study provides the first evidence of TE as a potential therapeutic for myxomatous mitral disease, either used to prevent or reverse myxomatous degeneration.
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Affiliation(s)
- Xinmei Wang
- Department of Bioengineering, Shenyang University, Shenyang, China
| | | | - Pablo Lapuerta
- Lexicon Pharmaceuticals, Basking Ridge, NJ, United States
| | - Carla M. R. Lacerda
- Department of Chemical Engineering, The University of Texas at Tyler, Tyler, TX, United States
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6
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Early Inactivation of Membrane Estrogen Receptor Alpha (ERα) Recapitulates the Endothelial Dysfunction of Aged Mouse Resistance Arteries. Int J Mol Sci 2022; 23:ijms23052862. [PMID: 35270003 PMCID: PMC8911509 DOI: 10.3390/ijms23052862] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 02/28/2022] [Accepted: 03/03/2022] [Indexed: 12/11/2022] Open
Abstract
Flow-mediated dilation (FMD) of resistance arteries is essential for tissue perfusion but it decreases with ageing. As estrogen receptor alpha (Erα encoded by Esr1), and more precisely membrane ERα, plays an important role in FMD in young mice in a ligand-independent fashion, we evaluated its influence on this arteriolar function in ageing. We first confirmed that in young (6-month-old) mice, FMD of mesenteric resistance arteries was reduced in Esr1−/− (lacking ERα) and C451A-ERα (lacking membrane ERα). In old (24-month-old) mice, FMD was reduced in WT mice compared to young mice, whereas it was not further decreased in Esr1−/− and C451A-ERα mice. Markers of oxidative stress were similarly increased in old WT and C451A-ERα mice. Reduction in oxidative stress with superoxide dismutase plus catalase or Mito-tempo, which reduces mitochondrial superoxide restored FMD to a normal control level in young C451A-ERα mice as well as in old WT mice and old C451A-ERα mice. Estradiol-mediated dilation was absent in old WT mice. We conclude that oxidative stress is a key event in the decline of FMD, and that an early defect in membrane ERα recapitulates phenotypically and functionally ageing of these resistance arteries. The loss of this function could take part in vascular ageing.
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7
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Harraz OF, Jensen LJ. Vascular calcium signalling and ageing. J Physiol 2021; 599:5361-5377. [PMID: 34705288 PMCID: PMC9002240 DOI: 10.1113/jp280950] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 10/12/2021] [Indexed: 02/05/2023] Open
Abstract
Changes in cellular Ca2+ levels have major influences on vascular function and blood pressure regulation. Vascular smooth muscle cells (SMCs) and endothelial cells (ECs) orchestrate vascular activity in distinct ways, often involving highly specific fluctuations in Ca2+ signalling. Ageing is a major risk factor for cardiovascular diseases, but the impact of ageing per se on vascular Ca2+ signalling has received insufficient attention. We reviewed the literature for age-related changes in Ca2+ signalling in relation to vascular structure and function. Vascular tone dysregulation in several vascular beds has been linked to abnormal expression or activity of SMC voltage-gated Ca2+ channels, Ca2+ -activated K+ channels or TRPC6 channels. Some of these effects were linked to altered caveolae density, microRNA expression or 20-HETE abundance. Intracellular store Ca2+ handling was suppressed in ageing mainly via reduced expression of intracellular Ca2+ release channels, and Ca2+ reuptake or efflux pumps. An increase in mitochondrial Ca2+ uptake, leading to oxidative stress, could also play a role in SMC hypercontractility and structural remodelling in ageing. In ECs, ageing entailed diverse effects on spontaneous and evoked Ca2+ transients, as well as structural changes at the EC-SMC interface. The concerted effects of altered Ca2+ signalling on myogenic tone, endothelium-dependent vasodilatation, and vascular structure are likely to contribute to blood pressure dysregulation and blood flow distribution deficits in critical organs. With the increase in the world's ageing population, future studies should be directed at solving specific ageing-induced Ca2+ signalling deficits to combat the imminent accelerated vascular ageing and increased risk of cardiovascular diseases.
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Affiliation(s)
- Osama F. Harraz
- Department of Pharmacology, Larner College of Medicine, University of Vermont, Burlington, Vermont, USA,Vermont Center for Cardiovascular and Brain Health, University of Vermont, Burlington, Vermont, USA
| | - Lars Jørn Jensen
- Pathobiological Sciences, Department of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Frederiksberg C, Denmark
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8
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Nemeth Z, Ryan MJ, Granger JP, Drummond HA. Expression of Exogenous Epithelial Sodium Channel Beta Subunit in the Mouse Middle Cerebral Artery Increases Pressure-Induced Constriction. Am J Hypertens 2021; 34:1227-1235. [PMID: 34161569 PMCID: PMC9526803 DOI: 10.1093/ajh/hpab098] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 06/18/2021] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Pressure-induced constriction (PIC) is inherent to small arteries and arterioles, in which intraluminal pressure-induced vascular smooth muscle cell stretch elicits vasoconstriction. Degenerin (Deg) proteins, such as beta-epithelial Na+ channel (βENaC), have been studied in the PIC response because they are evolutionarily linked to known mechanosensors. While loss of Deg function phenotypes are plentiful, a gain-of-function phenotype has not been studied. The aim of this study was to determine if expression of exogenous βENaC in the isolated middle cerebral artery (MCA) enhances the PIC response. METHODS Isolated MCA segments from female mice (24 weeks, n = 5) were transfected with enhanced green fluorescent protein-βENaC (EGFP-βENaC) or with EGFP alone, incubated overnight at 37 °C, then studied in a pressure myograph. RESULTS Mechanical/morphological properties and vasoconstrictor responses to KCl and phenylephrine were identical in EGFP-βENaC and EGFP MCAs. In contrast, PIC responses were greater in EGFP-βENaC segments with ~2-fold greater peak myogenic tone. CONCLUSIONS These data confirm previous findings that βENaC is critical in the PIC response. These data provide proof-of-concept that upregulating βENaC can enhance PIC responses and lay the foundation to test the hypothesis that inflammation-mediated downregulation of βENaC contributes to cerebrovascular dysfunction.
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Affiliation(s)
- Zoltan Nemeth
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Michael J Ryan
- Department of Pharmacology, Physiology and Neuroscience, University of South Carolina School of Medicine, Columbia, South Carolina, USA
| | - Joey P Granger
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
| | - Heather A Drummond
- Department of Physiology and Biophysics, University of Mississippi Medical Center, Jackson, Mississippi, USA
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9
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Rabaglino MB, Wakabayashi M, Pearson JT, Jensen LJ. Effect of age on the vascular proteome in middle cerebral arteries and mesenteric resistance arteries in mice. Mech Ageing Dev 2021; 200:111594. [PMID: 34756926 DOI: 10.1016/j.mad.2021.111594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Revised: 10/11/2021] [Accepted: 10/26/2021] [Indexed: 10/20/2022]
Abstract
Aging is associated with hypertension and brain blood flow dysregulation, which are major risk factors for cardiovascular and neurodegenerative diseases. Structural remodeling, endothelial dysfunction, or hypercontractility of resistance vessels may cause increased total peripheral resistance and hypertension. Recent studies showed that G protein- and RhoA/Rho-kinase pathways are involved in increased mean arterial pressure (MAP) and arterial tone in middle-aged mice. We aimed to characterize the age-dependent changes in the vascular proteome in normal laboratory mice using mass spectrometry and bioinformatics analyses on middle cerebral arteries and mesenteric resistance arteries from young (3 months) vs. middle-aged (14 months) mice. In total, 31 proteins were significantly affected by age whereas 172 proteins were differentially expressed by vessel type. Hierarchical clustering revealed that 207 proteins were significantly changed or clustered by age. Vitamin B6 pathway, Biosynthesis of antibiotics, Regulation of actin cytoskeleton and Endocytosis were the top enriched KEGG pathways by age. Several proteins in the RhoA/Rho-kinase pathway changed in a manner consistent with hypertension and dysregulation of cerebral perfusion. Although aging had a less profound effect than vessel type on the resistance artery proteome, regulation of actin cytoskeleton, including the RhoA/Rho-kinase pathway, is an important target for age-dependent hypertension.
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Affiliation(s)
- Maria Belen Rabaglino
- Dept. of Applied Mathematics and Computer Science, Danish Technical University, Denmark
| | - Masaki Wakabayashi
- Omics Research Center, National Cerebral and Cardiovascular Center, Osaka, Japan
| | - James Todd Pearson
- Dept. of Cardiac Physiology, National Cerebral and Cardiovascular Center Research Institute, Osaka, Japan; Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, Australia
| | - Lars Jørn Jensen
- Dept. of Veterinary and Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Denmark.
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Mouat MA, Coleman JLJ, Wu J, Dos Remedios CG, Feneley MP, Graham RM, Smith NJ. Involvement of GPR37L1 in murine blood pressure regulation and human cardiac disease pathophysiology. Am J Physiol Heart Circ Physiol 2021; 321:H807-H817. [PMID: 34533400 DOI: 10.1152/ajpheart.00198.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 09/14/2021] [Indexed: 01/23/2023]
Abstract
Multiple mouse lines lacking the orphan G protein-coupled receptor, GPR37L1, have elicited disparate cardiovascular phenotypes. The first Gpr37l1 knockout mice study to be published reported a marked elevation in systolic blood pressure (SBP; ∼60 mmHg), revealing a potential therapeutic opportunity. The phenotype differed from our own independently generated knockout line, where male mice exhibited equivalent baseline blood pressure to wild type. Here, we attempted to reproduce the first study by characterizing the cardiovascular phenotype of both the original knockout and transgenic lines alongside a C57BL/6J control line, using the same method of blood pressure measurement. The present study supports the findings from our independently developed Gpr37l1 knockout line, finding that SBP and diastolic blood pressure (DBP) are not different in the original Gpr37l1 knockout male mice (SBP: 130.9 ± 5.3 mmHg; DBP: 90.7 ± 3.0 mmHg) compared with C57BL/6J mice (SBP: 123.1 ± 4.1 mmHg; DBP: 87.0 ± 2.7 mmHg). Instead, we attribute the apparent hypertension of the knockout line originally described to comparison with a seemingly hypotensive transgenic line (SBP 103.7 ± 5.0 mmHg; DBP 71.9 ± 3.7 mmHg). Additionally, we quantified myocardial GPR37L1 transcript in humans, which was suggested to be downregulated in cardiovascular disease. We found that GPR37L1 has very low native transcript levels in human myocardium and that expression is not different in tissue samples from patients with heart failure compared with sex-matched healthy control tissue. These findings indicate that cardiac GPR37L1 expression is unlikely to contribute to the pathophysiology of human heart failure.NEW & NOTEWORTHY This study characterizes systolic blood pressure (SBP) in a Gpr37l1 knockout mouse line, which was previously reported to have ∼60 mmHg higher SBP compared with a transgenic line. We observed only a ∼27 mmHg SBP difference between the lines. However, when compared with C57BL/6J mice, knockout mice showed no difference in SBP. We also investigated GPR37L1 mRNA abundance in human hearts and observed no difference between healthy and failing heart samples.
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Affiliation(s)
- Margaret A Mouat
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - James L J Coleman
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Jianxin Wu
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- Cardiac Physiology and Transplantation Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Cristobal G Dos Remedios
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Michael P Feneley
- Cardiac Physiology and Transplantation Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Robert M Graham
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
| | - Nicola J Smith
- Molecular Pharmacology Laboratory, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
- St Vincent's Clinical School, UNSW Sydney, Sydney, New South Wales, Australia
- Molecular Cardiology and Biophysics Division, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia
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Trott DW, Machin DR, Phuong TTT, Adeyemo AO, Bloom SI, Bramwell RC, Sorensen ES, Lesniewski LA, Donato AJ. T cells mediate cell non-autonomous arterial ageing in mice. J Physiol 2021; 599:3973-3991. [PMID: 34164826 DOI: 10.1113/jp281698] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/21/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Increased large artery stiffness and impaired endothelium-dependent dilatation occur with advanced age. We sought to determine whether T cells mechanistically contribute to age-related arterial dysfunction. We found that old mice exhibited greater proinflammatory T cell accumulation around both the aorta and mesenteric arteries. Pharmacologic depletion or genetic deletion of T cells in old mice resulted in ameliorated large artery stiffness and greater endothelium-dependent dilatation compared with mice with T cells intact. ABSTRACT Ageing of the arteries is characterized by increased large artery stiffness and impaired endothelium-dependent dilatation. T cells contribute to hypertension in acute rodent models but whether they contribute to chronic age-related arterial dysfunction is unknown. To determine whether T cells directly mediate age-related arterial dysfunction, we examined large elastic artery and resistance artery function in young (4-6 months) and old (22-24 months) wild-type mice treated with anti-CD3 F(ab'2) fragments to deplete T cells (150 μg, i.p. every 7 days for 28 days) or isotype control fragments. Old mice exhibited greater numbers of T cells in both aorta and mesenteric vasculature when compared with young mice. Old mice treated with anti-CD3 fragments exhibited depletion of T cells in blood, spleen, aorta and mesenteric vasculature. Old mice also exhibited greater numbers of aortic and mesenteric IFN-γ and TNF-α-producing T cells when compared with young mice. Old control mice exhibited greater large artery stiffness and impaired resistance artery endothelium-dependent dilatation in comparison with young mice. In old mice, large artery stiffness was ameliorated with anti-CD3 treatment. Anti-CD3-treated old mice also exhibited greater endothelium-dependent dilatation than age-matched controls. We also examined arterial function in young and old Rag-1-/- mice, which lack lymphocytes. Rag-1-/- mice exhibited blunted increases in large artery stiffness with age compared with wild-type mice. Old Rag-1-/- mice also exhibited greater endothelium-dependent dilatation compared with old wild-type mice. Collectively, these results demonstrate that T cells play an important role in age-related arterial dysfunction.
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Affiliation(s)
- Daniel W Trott
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Kinesiology, University of Texas at Arlington, Texas, USA
| | - Daniel R Machin
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Tam T T Phuong
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - AdeLola O Adeyemo
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - R Colton Bramwell
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Eric S Sorensen
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Lisa A Lesniewski
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Geriatrics Research Education and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, Utah, USA
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Geriatrics Research Education and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, Utah, USA.,Department of Biochemistry, University of Utah, Salt Lake City, Utah, USA
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Ogoh S, Sato K, de Abreu S, Denise P, Normand H. Effect of jump exercise training on long-term head-down bed rest-induced cerebral blood flow responses in arteries and veins. Exp Physiol 2021; 106:1549-1558. [PMID: 33866619 DOI: 10.1113/ep089102] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2020] [Accepted: 03/29/2021] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? What is the effect of an exercise countermeasure on microgravity-induced change in cerebral blood flow? What is the main finding and its importance? Jump exercise training as a countermeasure did not modify the heterogeneous cerebral blood flow response to head-down bed rest, suggesting that this method is effective in preventing cardiovascular system deconditioning but is not good for cerebral haemodynamics. ABSTRACT This study aimed to examine the effect of an exercise countermeasure on cerebral blood flow (CBF) response to long-term -6° head-down bed rest (HDBR) in all cerebral arteries and veins. Twenty male volunteers were exposed to HDBR for 60 days with (training group, n = 10) or without (control group, n = 10) jump exercise training as a countermeasure to spaceflight. The blood flow in the neck conduit arteries (internal carotid and vertebral artery; ICA and VA) and veins (internal jugular and vertebral veins; IJV and VV) was measured, using ultrasonography before (baseline) HDBR, on the 30th and 57th day of HDBR. Long-term HDBR causes a heterogeneous CBF response between the anterior and the posterior brain or between arteries and veins. Long-term HDBR decreased anterior cerebral arterial and venous blood flow, while posterior cerebral arterial and venous blood flows were well maintained. However, exercise jump training did not change each arterial and venous CBF responses to HDBR (control vs. training; ICA, P = 0.643; VA, P = 0.542; external carotid artery, P = 0.644; IJV, P = 0.980; VV, P = 0.999). These findings suggest that jump exercise training did not modify the heterogeneous CBF response to long-term HDBR.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | | | - Steven de Abreu
- Unicaen, Inserm Comete, GIP Cyceron, Normandie University, Caen, France
| | - Pierre Denise
- Unicaen, Inserm Comete, GIP Cyceron, Normandie University, Caen, France
| | - Hervé Normand
- Unicaen, Inserm Comete, GIP Cyceron, Normandie University, Caen, France
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13
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Mittal A, Park PD, Mitchell R, Fang H, Bagher P. Comparison of Adrenergic and Purinergic Receptor Contributions to Vasomotor Responses in Mesenteric Arteries of C57BL/6J Mice and Wistar Rats. J Vasc Res 2020; 58:1-15. [PMID: 33311016 DOI: 10.1159/000511462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 09/07/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The sympathetic nervous system can modulate arteriolar tone through release of adenosine triphosphate and norepinephrine, which bind to purinergic and adrenergic receptors (ARs), respectively. The expression pattern of these receptors, as well as the composition of neurotransmitters released from perivascular nerves (PVNs), can vary both in organ systems within and across species, such as mice and rats. OBJECTIVE This study explores the function of α1A subtypes in mouse and rat third-order mesenteric arteries and investigates PVN-mediated vasoconstriction to identify which neurotransmitters are released from sympathetic PVNs. METHODS Third-order mesenteric arteries from male C57BL/6J mice and Wistar rats were isolated and mounted on a wire myograph for functional assessment. Arteries were exposed to phenylephrine (PE) and then incubated with either α1A antagonist RS100329 (RS) or α1D antagonist BMY7378, before reexposure to PE. Electrical field stimulation was performed by passing current through platinum electrodes positioned adjacent to arteries in the absence and presence of a nonspecific alpha AR blocker phentolamine and/or P2X1-specific purinergic receptor blocker NF449. RESULTS Inhibition of α1 ARs by RS revealed that PE-induced vasoconstriction is primarily mediated through α1A and that the contribution of the α1A AR is greater in rats than in mice. In the mouse model, sympathetic nerve-mediated vasoconstriction is mediated by both ARs and purinergic receptors, whereas in rats, vasoconstriction appeared to only be mediated by ARs and a nonpurinergic neurotransmitter. Further, neither model demonstrated that α1D ARs play a significant role in PE-mediated vasoconstriction. CONCLUSIONS The mesenteric arteries of male C57BL/6J mice and Wistar rats have subtle differences in the signaling mechanisms used to mediate vasoconstriction. As signaling pathways in humans under physiological and pathophysiological conditions become better defined, the current study may inform animal model selection for preclinical studies.
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Affiliation(s)
- Astha Mittal
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Peter D Park
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Ray Mitchell
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA
| | - Hanwei Fang
- Department of Microbiology and Molecular Medicine University of Geneva, Geneva, Switzerland
| | - Pooneh Bagher
- Department of Medical Physiology, Texas A&M University Health Science Center, Bryan, Texas, USA,
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14
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Buchmann GK, Schürmann C, Warwick T, Schulz MH, Spaeth M, Müller OJ, Schröder K, Jo H, Weissmann N, Brandes RP. Deletion of NoxO1 limits atherosclerosis development in female mice. Redox Biol 2020; 37:101713. [PMID: 32949971 PMCID: PMC7502371 DOI: 10.1016/j.redox.2020.101713] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Revised: 08/28/2020] [Accepted: 08/29/2020] [Indexed: 01/22/2023] Open
Abstract
OBJECTIVE Oxidative stress is a risk factor for atherosclerosis. NADPH oxidases of the Nox family produce ROS but their contribution to atherosclerosis development is less clear. Nox2 promotes and Nox4 rather limits atherosclerosis. Although Nox1 with its cytosolic co-factors are largely expressed in epithelial cells, a role for Nox1 for atherosclerosis development was suggested. To further define the role of this homologue, the role of its essential cytosolic cofactor, NoxO1, was determined for atherosclerosis development with the aid of knockout mice. METHODS AND RESULTS Wildtype (WT) and NoxO1 knockout mice were treated with high fat diet and adeno-associated virus (AAV) overexpressing pro-protein convertase subtilisin/kexin type 9 (PCSK9) to induce hepatic low-density lipoprotein (LDL) receptor loss. As a result, massive hypercholesterolemia was induced and spontaneous atherosclerosis developed within three month. Deletion of NoxO1 reduced atherosclerosis formation in brachiocephalic artery and aortic arch in female but not male NoxO1-/- mice as compared to WT littermates. This was associated with a reduced pro-inflammatory cytokine signature in the plasma of female but not male NoxO1-/- mice. MACE-RNAseq of the vessel did not reveal this signature and the expression of the Nox1/NoxO1 system was low to not detectable. CONCLUSIONS The scaffolding protein NoxO1 plays some role in atherosclerosis development in female mice probably by attenuating the global inflammatory burden.
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Affiliation(s)
- Giulia K Buchmann
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Christoph Schürmann
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Tim Warwick
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Marcel H Schulz
- German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; Institute for Cardiovascular Regeneration, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Manuela Spaeth
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Oliver J Müller
- Department of Internal Medicine III, University of Kiel, Arnold-Heller-Straße 3, 24105, Kiel, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Hamburg/Kiel/Lübeck, Arnold-Heller-Straße 3, 24105, Kiel, Germany
| | - Katrin Schröder
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany
| | - Hanjoong Jo
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, 313 Ferst Dr NW, Atlanta, GA, 30332, USA
| | - Norbert Weissmann
- Excellence Cluster Cardio-Pulmonary Institute (CPI), Universities of Giessen and Marburg Lung Center (UGMLC), Member of the German Center for Lung Research (DZL), Ludwigstraße 23, 35390, Gießen, Germany
| | - Ralf P Brandes
- Institute for Cardiovascular Physiology, Goethe-University, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany; German Center for Cardiovascular Research (DZHK), Partner Site Rhein Main, Theodor-Stern Kai 7, 60590, Frankfurt Am Main, Germany.
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15
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Nunes KP, Webb RC. New insights into RhoA/Rho-kinase signaling: a key regulator of vascular contraction. Small GTPases 2020; 12:458-469. [PMID: 32970516 DOI: 10.1080/21541248.2020.1822721] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023] Open
Abstract
While Rho-signalling controlling vascular contraction is a canonical mechanism, with the modern approaches used in research, we are advancing our understanding and details into this pathway are often uncovered. RhoA-mediated Rho-kinase is the major regulator of vascular smooth muscle cells and a key player manoeuvring other functions in these cells. The discovery of new interactions, such as oxidative stress and hydrogen sulphide with Rho signalling are emerging addition not only in the physiology of the smooth muscle, but especially in the pathophysiology of vascular diseases. Likewise, the interplay between ageing and Rho-kinase in the vasculature has been recently considered. Importantly, in smooth muscle contraction, this pathway may also be affected by sex hormones, and consequently, sex-differences. This review provides an overview of Rho signalling mediating vascular contraction and focuses on recent topics discussed in the literature affecting this pathway such as ageing, sex differences and oxidative stress.
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Affiliation(s)
- Kenia Pedrosa Nunes
- Laboratory of Vascular Physiology, Department of Biomedical and Chemical Engineering and Sciences, Florida Institute of Technology, Melbourne, FL, USA
| | - R Clinton Webb
- Department of Cell Biology and Anatomy, University of South Carolina, Columbia, SC, USA
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16
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Wang S, Lv W, Zhang H, Liu Y, Li L, Jefferson JR, Guo Y, Li M, Gao W, Fang X, Paul IA, Rajkowska G, Shaffery JP, Mosley TH, Hu X, Liu R, Wang Y, Yu H, Roman RJ, Fan F. Aging exacerbates impairments of cerebral blood flow autoregulation and cognition in diabetic rats. GeroScience 2020; 42:1387-1410. [PMID: 32696219 DOI: 10.1007/s11357-020-00233-w] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus (DM) is a leading risk factor for aging-related dementia; however, the underlying mechanisms are not well understood. The present study, utilizing a non-obese T2DN diabetic model, demonstrates that the myogenic response of the middle cerebral artery (MCA) and parenchymal arteriole (PA) and autoregulation of cerebral blood flow (CBF) in the surface and deep cortex were impaired at both young and old ages. The impaired CBF autoregulation was more severe in old than young DM rats, and in the deep than the surface cortex. The myogenic tone of the MCA was enhanced at perfusion pressure in the range of 40-100 mmHg in young DM rats but was reduced at 140-180 mmHg in old DM rats. No change of the myogenic tone of the PA was observed in young DM rats, whereas it was significantly reduced at 30-60 mmHg in old DM rats. Old DM rats had enhanced blood-brain barrier (BBB) leakage and neurodegeneration, reduced vascular density, tight junction, and pericyte coverage on cerebral capillaries in the CA3 region in the hippocampus. Additionally, DM rats displayed impaired functional hyperemia and spatial learning and short- and long-term memory at both young and old ages. Old DM rats had impaired non-spatial short-term memory. These results revealed that impaired CBF autoregulation and enhanced BBB leakage plays an essential role in the pathogenesis of age- and diabetes-related dementia. These findings will lay the foundations for the discovery of anti-diabetic therapies targeting restoring CBF autoregulation to prevent the onset and progression of dementia in elderly DM.
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Affiliation(s)
- Shaoxun Wang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenshan Lv
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.,Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Huawei Zhang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Yedan Liu
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Longyang Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Joshua R Jefferson
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ya Guo
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Man Li
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Wenjun Gao
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Xing Fang
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Ian A Paul
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Grazyna Rajkowska
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - James P Shaffery
- Department of Psychiatry and Human Behavior, University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Thomas H Mosley
- Department of Neurology, University of Mississippi Medical Center, Jackson, MS, 39216, USA.,Department of Medicine (Geriatrics), University of Mississippi Medical Center, Jackson, MS, 39216, USA
| | - Xinlin Hu
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Ruen Liu
- Department of Neurosurgery, Peking University People's Hospital, Beijing, 100044, China
| | - Yangang Wang
- Department of Endocrinology and Metabolic, The Affiliated Hospital of Qingdao University, Qingdao, 266003, Shandong, China
| | - Hongwei Yu
- Department of Anesthesiology, Medical College of Wisconsin, Milwaukee, WI, 53226, USA
| | - Richard J Roman
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA
| | - Fan Fan
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS, 39216, USA.
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17
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Fisch S, Bachner-Hinenzon N, Ertracht O, Guo L, Arad Y, Ben-Zvi D, Liao R, Schneiderman J. Localized Antileptin Therapy Prevents Aortic Root Dilatation and Preserves Left Ventricular Systolic Function in a Murine Model of Marfan Syndrome. J Am Heart Assoc 2020; 9:e014761. [PMID: 32378446 PMCID: PMC7660857 DOI: 10.1161/jaha.119.014761] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background Marfan syndrome (MFS) is a genetically transmitted connective tissue disorder characterized by aortic root dilatation, dissection, and rupture. Molecularly, MFS pathological features have been shown to be driven by increased angiotensin II in the aortic wall. Using an angiotensin II-driven aneurysm mouse model, we have recently demonstrated that local inhibition of leptin activity restricts aneurysm formation in the ascending and abdominal aorta. As we observed de novo leptin synthesis in the ascending aortic aneurysm wall of patients with MFS, we hypothesized that local counteracting of leptin activity in MFS may also prevent aortic cardiovascular complications in this context. Methods and Results Fbn1C1039G/+ mice underwent periaortic application of low-dose leptin antagonist at the aortic root. Treatment abolished medial degeneration and prevented increase in aortic root diameter (P<0.001). High levels of leptin, transforming growth factor β1, Phosphorylated Small mothers against decapentaplegic 2, and angiotensin-converting enzyme 1 observed in saline-treated MFS mice were downregulated in leptin antagonist-treated animals (P<0.01, P<0.05, P<0.001, and P<0.001, respectively). Leptin and angiotensin-converting enzyme 1 expression levels in left ventricular cardiomyocytes were also decreased (P<0.001) and coincided with prevention of left ventricular hypertrophy and aortic and mitral valve leaflet thickening (P<0.01 and P<0.05, respectively) and systolic function preservation. Conclusions Local, periaortic application of leptin antagonist prevented aortic root dilatation and left ventricular valve remodeling, preserving left ventricular systolic function in an MFS mouse model. Our results suggest that local inhibition of leptin may constitute a novel, stand-alone approach to prevent MFS aortic root aneurysms and potentially other similar angiotensin II-driven aortic pathological features.
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Affiliation(s)
- Sudeshna Fisch
- Cardiovascular Physiology Core Department of Medicine Brigham and Women's Hospital Harvard Medical School Boston MA
| | | | - Offir Ertracht
- Eliachar Research Laboratory Galilee Medical Center Nahariya Israel
| | | | - Yhara Arad
- Department of Developmental Biology and Cancer Research Institute of Medical Research Israel-Canada Hebrew University of Jerusalem-Hadassah Medical School Jerusalem Israel
| | - Danny Ben-Zvi
- Department of Developmental Biology and Cancer Research Institute of Medical Research Israel-Canada Hebrew University of Jerusalem-Hadassah Medical School Jerusalem Israel
| | - Ronglih Liao
- Cardiovascular Physiology Core Department of Medicine Brigham and Women's Hospital Harvard Medical School Boston MA.,Stanford University School of Medicine Cardiovascular Institute Stanford CA
| | - Jacob Schneiderman
- Department of Vascular Surgery Sheba Medical Center Sackler Faculty of Medicine Tel Aviv University Tel Aviv Israel
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18
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Caulk AW, Humphrey JD, Murtada SI. Fundamental Roles of Axial Stretch in Isometric and Isobaric Evaluations of Vascular Contractility. J Biomech Eng 2020; 141:2718205. [PMID: 30516238 DOI: 10.1115/1.4042171] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Indexed: 12/22/2022]
Abstract
Vascular smooth muscle cells (VSMCs) can regulate arterial mechanics via contractile activity in response to changing mechanical and chemical signals. Contractility is traditionally evaluated via uniaxial isometric testing of isolated rings despite the in vivo environment being very different. Most blood vessels maintain a locally preferred value of in vivo axial stretch while subjected to changes in distending pressure, but both of these phenomena are obscured in uniaxial isometric testing. Few studies have rigorously analyzed the role of in vivo loading conditions in smooth muscle function. Thus, we evaluated effects of uniaxial versus biaxial deformations on smooth muscle contractility by stimulating two regions of the mouse aorta with different vasoconstrictors using one of three testing protocols: (i) uniaxial isometric testing, (ii) biaxial isometric testing, and (iii) axially isometric plus isobaric testing. Comparison of methods (i) and (ii) revealed increased sensitivity and contractile capacity to potassium chloride and phenylephrine (PE) with biaxial isometric testing, and comparison of methods (ii) and (iii) revealed a further increase in contractile capacity with isometric plus isobaric testing. Importantly, regional differences in estimated in vivo axial stretch suggest locally distinct optimal biaxial configurations for achieving maximal smooth muscle contraction, which can only be revealed with biaxial testing. Such differences highlight the importance of considering in vivo loading and geometric configurations when evaluating smooth muscle function. Given the physiologic relevance of axial extension and luminal pressurization, we submit that, when possible, axially isometric plus isobaric testing should be employed to evaluate vascular smooth muscle contractile function.
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Affiliation(s)
- Alexander W Caulk
- Department of Biomedical Engineering, Yale University, New Haven, CT 06520
| | - Jay D Humphrey
- Fellow ASME Department of Biomedical Engineering, Yale University, New Haven, CT 06520.,Vascular Biology and Therapeutics Program, Yale University, New Haven, CT 06520
| | - Sae-Il Murtada
- Department of Biomedical Engineering, Yale University, 55 Prospect Street, New Haven, CT 06520 e-mail:
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19
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Shahid A, Patel VB, Morton JS, Stenson TH, Davidge ST, Oudit GY, McMurtry MS. Low altitude simulation without hypoxia improves left ventricular function after myocardial infarction by reducing ventricular afterload. PLoS One 2019; 14:e0215814. [PMID: 31150412 PMCID: PMC6544215 DOI: 10.1371/journal.pone.0215814] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2018] [Accepted: 04/09/2019] [Indexed: 01/10/2023] Open
Abstract
Humans have a lower risk of death from myocardial infarction (MI) living at low elevations (<2500 m), which are not high enough to induce hypoxia. Both chronic hypoxia pre-MI, achieved by altitude simulation >5000 m, and intermittent hypobaric hypoxia post-MI can reduce MI size in rodents, and it is believed that hypoxia is the key stimulus. To explore mechanisms beyond hypoxia we studied whether altitude simulation <2500 m would also be associated with reduced infarct size. We performed left-anterior descending artery ligation on C57BL6 mice. Control mice (n = 12) recovered at 754 mmHg (atmospheric pressure, control), and treatment group mice (n = 13) were placed in a hypobaric chamber to recover 3-hours daily at 714 mmHg for 1 week. Echocardiographic evaluation of left ventricular function was performed on Day 0, Day 1 and Day 8. Intermittent hypobaric treatment was associated with a 14.2±5.3% improvement in ejection fraction for treatment group mice (p<0.01 vs. Day 1), with no change observed in control mice. Cardiac output, stroke volume, and infarct size were also improved in treated mice, but no changes were observed in HIF-1 activation or neovascularization. Next, we studied the acute hemodynamic effects of low altitude stimulation in intact mice breathing 100% oxygen using left ventricular catheterization and recording of pressure-volume loops. Acute reductions in barometric pressure from 754 mmHg to 714 mmHg and 674 mmHg were associated with reduced systemic vascular resistance, increased stroke volume and cardiac output, and no change in blood pressure or heart rate. Ex-vivo vascular function was studied using murine mesenteric artery segments. Acute reductions in barometric pressure were associated with greater vascular distensibility. We conclude that intermittent hypobaric treatment using simulated altitudes <2500 m reduces infarct size and increases ventricular function post-MI, and that these changes are related to altered arterial function and not hypoxia-associated neovascularization.
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Affiliation(s)
- Anmol Shahid
- Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Vaibhav B. Patel
- Libin Cardiovascular Institute of Alberta, University of Calgary, Calgary, Alberta, Canada
| | - Jude S. Morton
- Dept. of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | | | - Sandra T. Davidge
- Dept. of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
| | - Gavin Y. Oudit
- Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Michael S. McMurtry
- Dept. of Medicine, University of Alberta, Edmonton, Alberta, Canada
- * E-mail:
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20
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Ogoh S, Sato K, Hirasawa A, Sadamoto T. The effect of muscle metaboreflex on the distribution of blood flow in cerebral arteries during isometric exercise. J Physiol Sci 2019; 69:375-385. [PMID: 30604287 PMCID: PMC10717543 DOI: 10.1007/s12576-018-0653-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Accepted: 12/11/2018] [Indexed: 12/20/2022]
Abstract
The present study examined the effect of muscle metaboreflex on blood flow in different cerebral arteries. Eleven healthy participants performed isometric, one-leg knee extension at 30% maximal voluntary contraction for 2 min. Activated muscle metaboreflex was isolated for 2 min by post-exercise muscle ischemia (PEMI). The contralateral internal carotid (ICA), vertebral (VA), and ipsilateral external carotid arteries (ECA) blood flows were evaluated using Doppler ultrasound. The ICA blood flow increased at the beginning of exercise (P = 0.004) but returned to the baseline level at the end of exercise (P = 0.055). In contrast, the VA blood flow increased and it was maintained until the end of the exercise (P = 0.011), while the ECA blood flow gradually increased throughout the exercise (P = 0.001). These findings indicate that isometric exercise causes a heterogeneous cerebral blood flow response in different cerebral arteries. During PEMI, the conductance of the VA as well as that of the ICA was significantly lower compared with the baseline value (P = 0.020 and P = 0.032, at PEMI90), while the conductance of the ECA was not different from the baseline (P = 0.587), suggesting that the posterior and anterior cerebral vasculature were similarly affected during exercise by activation of muscle metaboreceptors, but not in the non-cerebral artery. Since ECA branches from ICA, the balance in the different influence of muscle metaboreflex on ECA (vasodilation via exercise-induced hypertension) and ICA (vasoconstriction) may contribute to the decrease in ICA blood flow at the end of isometric exercise.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.
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21
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Smoothelin-like 1 deletion enhances myogenic reactivity of mesenteric arteries with alterations in PKC and myosin phosphatase signaling. Sci Rep 2019; 9:481. [PMID: 30679490 PMCID: PMC6346088 DOI: 10.1038/s41598-018-36564-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Accepted: 11/23/2018] [Indexed: 11/18/2022] Open
Abstract
The role of the smoothelin-like 1 (SMTNL1) protein in mediating vascular smooth muscle contractile responses to intraluminal pressure was examined in resistance vessels. Mesenteric arterioles from wild type (WT) and SMTNL1 global knock-out (KO) mice were examined with pressure myography. SMTNL1 deletion was associated with enhanced myogenic tone in vessels isolated from male, but not female, mice. Intraluminal pressures greater than 40 mmHg generated statistically significant differences in myogenic reactivity between WT and KO vessels. No overt morphological differences were recorded for vessels dissected from KO animals, but SMTNL1 deletion was associated with loss of myosin phosphatase-targeting protein MYPT1 and increase in the myosin phosphatase inhibitor protein CPI-17. Additionally, we observed altered contractile responses of isolated arteries from SMTNL1 KO mice to phenylephrine, KCl-dependent membrane depolarization and phorbol 12,13-dibutyrate (PDBu). Using pharmacological approaches, myogenic responses of both WT and KO vessels were equally affected by Rho-associated kinase (ROCK) inhibition; however, augmented protein kinase C (PKC) signaling was found to contribute to the increased myogenic reactivity of SMTNL1 KO vessels across the 60–120 mmHg pressure range. Based on these findings, we conclude that deletion of SMTNL1 contributes to enhancement of pressure-induced contractility of mesenteric resistance vessels by influencing the activity of myosin phosphatase.
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22
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Ogoh S, Yoo JK, Badrov MB, Parker RS, Anderson EH, Wiblin JL, North CS, Suris A, Fu Q. Cerebral blood flow regulation and cognitive function in women with posttraumatic stress disorder. J Appl Physiol (1985) 2018; 125:1627-1635. [DOI: 10.1152/japplphysiol.00502.2018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Posttraumatic stress disorder (PTSD) is associated with structural and functional alterations in a number of interacting brain regions, but the physiological mechanism for the high risk of cerebrovascular disease or impairment in brain function remains unknown. Women are more likely to develop PTSD after a trauma than men. We hypothesized that cerebral blood flow (CBF) regulation is impaired in women with PTSD, and it is associated with impairment in cognitive function. To test our hypothesis, we examined dynamic cerebral autoregulation (CA) and cognitive function by using a transfer function analysis between arterial pressure and middle cerebral artery blood velocity and the Stroop Color and Word test (SCWT), respectively. We did not observe any different responses in these hemodynamic variables between women with PTSD ( n = 15) and healthy counterparts (all women; n = 8). Cognitive function was impaired in women with PTSD; specifically, reaction time for the neutral task of SCWT was longer in women with PTSD compared with healthy counterparts ( P = 0.011), but this cognitive dysfunction was not affected by orthostatic stress. On the other hand, transfer function phase, gain, and coherence were not different between groups in either the supine or head-up tilt (60°) position, or even during the cognitive challenge, indicating that dynamic CA was well maintained in women with PTSD. In addition, there was no relationship between cognitive function and dynamic CA. These findings suggest that PTSD-related cognitive dysfunction may not be due to compromised CBF regulation. NEW & NOTEWORTHY Cognitive function was impaired; however, dynamic cerebral autoregulation (CA) as an index of cerebral blood flow regulation was not impaired during supine and 60° head-up tilt in women with PTSD compared with healthy females. In addition, there was no relationship between cognitive function and dynamic CA. These findings suggest that the mechanism of PTSD-related cognitive dysfunction may not be due to CBF regulation.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Jeung-Ki Yoo
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Texas
- University of Texas Southwestern Medical Center, Dallas, Texas
| | - Mark B. Badrov
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Texas
- University of Texas Southwestern Medical Center, Dallas, Texas
| | - Rosemary S. Parker
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Texas
| | - Elizabeth H. Anderson
- University of Texas Southwestern Medical Center, Dallas, Texas
- Veterans Affairs North Texas Health Care System, Dallas, Texas
| | - Jessica L. Wiblin
- University of Texas Southwestern Medical Center, Dallas, Texas
- Veterans Affairs North Texas Health Care System, Dallas, Texas
| | - Carol S. North
- Metrocare Services and the University of Texas Southwestern Medical Center, Dallas, Texas
| | - Alina Suris
- University of Texas Southwestern Medical Center, Dallas, Texas
- Veterans Affairs North Texas Health Care System, Dallas, Texas
| | - Qi Fu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Texas
- University of Texas Southwestern Medical Center, Dallas, Texas
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Washio T, Vranish JR, Kaur J, Young BE, Katayama K, Fadel PJ, Ogoh S. Acute reduction in posterior cerebral blood flow following isometric handgrip exercise is augmented by lower body negative pressure. Physiol Rep 2018; 6:e13886. [PMID: 30338667 PMCID: PMC6194212 DOI: 10.14814/phy2.13886] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Accepted: 09/16/2018] [Indexed: 01/31/2023] Open
Abstract
The mechanism(s) for the increased occurrence of a grayout or blackout, syncope, immediately after heavy resistance exercise are unclear. It is well-known that orthostatic stress increases the occurrence of postexercise syncope. In addition, previous findings have suggested that hypo-perfusion, especially in the posterior cerebral circulation rather than anterior cerebral circulation, may be associated with the occurrence of syncope. Herein, we hypothesized that the postexercise decrease in posterior, but not anterior, cerebral blood flow (CBF) would be greater during orthostatic stress. Nine healthy subjects performed 3-min isometric handgrip (HG) at 30% maximum voluntary contraction without (CONTROL) and during lower body negative pressure (LBNP; -40 Torr) while vertebral artery (VA) blood flow, as an index of posterior CBF, and middle cerebral artery blood velocity (MCAv), as an index of anterior CBF, were measured. Immediately after HG (0 to 15 sec of recovery phase), mean arterial pressure decreased but there was no difference in this reduction between CONTROL and LBNP conditions (-15.4 ± 4.0% and -17.0 ± 6.2%, P = 0.42). Similarly, MCAv decreased following exercise and was unaffected by the application of LBNP (P = 0.22). In contrast, decreases in VA blood flow immediately following HG during LBNP were significantly greater compared to CONTROL condition (-24.2 ± 9.5% and -13.4 ± 6.6%, P = 0.005). These findings suggest that the decrease in posterior CBF immediately following exercise was augmented by LBNP, whereas anterior CBF appeared unaffected. Thus, the posterior cerebral circulation may be more sensitive to orthostatic stress during the postexercise period.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical EngineeringToyo UniversityKawagoe‐shiSaitamaJapan
- Research Fellow of Japan Society for the Promotion of ScienceTokyoJapan
| | | | - Jasdeep Kaur
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Benjamin E. Young
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Keisho Katayama
- Research Center of HealthPhysical Fitness and SportsNagoya UniversityNagoyaJapan
| | - Paul J. Fadel
- Department of KinesiologyUniversity of Texas at ArlingtonArlingtonTexas
| | - Shigehiko Ogoh
- Department of Biomedical EngineeringToyo UniversityKawagoe‐shiSaitamaJapan
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Björling K, Joseph PD, Egebjerg K, Salomonsson M, Hansen JL, Ludvigsen TP, Jensen LJ. Role of age, Rho-kinase 2 expression, and G protein-mediated signaling in the myogenic response in mouse small mesenteric arteries. Physiol Rep 2018; 6:e13863. [PMID: 30198176 PMCID: PMC6129776 DOI: 10.14814/phy2.13863] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2018] [Accepted: 08/21/2018] [Indexed: 12/16/2022] Open
Abstract
The myogenic response (MR) and myogenic tone (MT) in resistance vessels is crucial for maintaining peripheral vascular resistance and blood flow autoregulation. Development of MT involves G protein-coupled receptors, and may be affected by aging. AIMS (1) to estimate the mesenteric blood flow in myogenically active small mesenteric arteries; (2) to investigate the signaling from Gαq/11 and/or Gα12 activation to MT development; (3) to investigate the role of Rho-kinase 2 and aging on MT in mesenteric resistance arteries. METHODS we used pressure myography, quantitative real-time PCR, and immunolocalization to study small (<200 μm) mesenteric arteries (SMA) from young, mature adult, and middle aged mice. RESULTS Poiseuille flow calculations indicated autoregulation of blood flow at 60-120 mm Hg arterial pressure. Gαq/11 and Gα12 were abundantly expressed at the mRNA and protein levels in SMA. The Gαq/11 inhibitor YM-254890 suppressed MT development, and the Phosholipase C inhibitors U73122 and ET-18-OCH3 robustly inhibited it. We found an age-dependent increase in ROCK2 mRNA expression, and in basal MT. The specific ROCK2 inhibitor KD025 robustly inhibited MT in SMAs in all mice with an age-dependent variation in KD025 sensitivity. The inhibitory effect of KD025 was not prevented by the L-type Ca2+ channel activator BayK 8644. KD025 reversibly inhibited MT and endothelin-1 vasoconstriction in small pial arteries from Göttingen minipigs. CONCLUSIONS MT development in SMAs occurs through a Gαq/11 /PLC/Ca2+ -dependent pathway, and is maintained via ROCK2-mediated Ca2+ sensitization. Increased MT at mature adulthood can be explained by increased ROCK2 expression/activity.
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Affiliation(s)
- Karl Björling
- Department of Veterinary and Animal SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenFrederiksberg CCopenhagenDenmark
| | - Philomeena D. Joseph
- Department of Veterinary and Animal SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenFrederiksberg CCopenhagenDenmark
| | - Kristian Egebjerg
- Department of Veterinary and Animal SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenFrederiksberg CCopenhagenDenmark
| | - Max Salomonsson
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagen NDenmark
- Department of Internal MedicineTrelleborg HospitalTrelleborgSweden
| | | | | | - Lars J. Jensen
- Department of Veterinary and Animal SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenFrederiksberg CCopenhagenDenmark
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25
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Ogoh S, Nakata H, Miyamoto T, Bailey DM, Shibasaki M. Dynamic cerebral autoregulation during cognitive task: effect of hypoxia. J Appl Physiol (1985) 2018; 124:1413-1419. [PMID: 29420157 DOI: 10.1152/japplphysiol.00909.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Changes in cerebral blood flow (CBF) subsequent to alterations in the partial pressures of oxygen and carbon dioxide can modify dynamic cerebral autoregulation (CA). While cognitive activity increases CBF, the extent to which it impacts CA remains to be established. In the present study we determined whether dynamic CA would decrease during a cognitive task and whether hypoxia would further compound impairment. Fourteen young healthy subjects performed a simple Go/No-go task during normoxia and hypoxia (inspired O2 fraction = 12%), and the corresponding relationship between mean arterial pressure (MAP) and mean middle cerebral artery blood velocity (MCA Vmean) was examined. Dynamic CA and steady-state changes in MCA V in relation to changes in arterial pressure were evaluated with transfer function analysis. While MCA Vmean increased during the cognitive activity ( P < 0.001), hypoxia did not cause any additional changes ( P = 0.804 vs. normoxia). Cognitive performance was also unaffected by hypoxia (reaction time, P = 0.712; error, P = 0.653). A decrease in the very low- and low-frequency phase shift (VLF and LF; P = 0.021 and P = 0.01) and an increase in LF gain were observed ( P = 0.037) during cognitive activity, implying impaired dynamic CA. While hypoxia also increased VLF gain ( P < 0.001), it failed to cause any additional modifications in dynamic CA. Collectively, our findings suggest that dynamic CA is impaired during cognitive activity independent of altered systemic O2 availability, although we acknowledge the interpretive complications associated with additional competing, albeit undefined, inputs that could potentially distort the MAP-MCA Vmean relationship. NEW & NOTEWORTHY During normoxia, cognitive activity while increasing cerebral perfusion was shown to attenuate dynamic cerebral autoregulation (CA) yet failed to alter reaction time, thereby questioning its functional significance. No further changes were observed during hypoxia, suggesting that impaired dynamic CA occurs independently of altered systemic O2 availability. However, impaired dynamic CA may reflect a technical artifact, given the confounding influence of additional inputs that could potentially distort the mean arterial pressure-mean middle cerebral artery blood velocity relationship.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University , Saitama , Japan
| | - Hiroki Nakata
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University , Nara , Japan
| | | | - Damian Miles Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales , Pontypridd , United Kingdom
| | - Manabu Shibasaki
- Department of Health Sciences, Faculty of Human Life and Environment, Nara Women's University , Nara , Japan
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26
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Sexual dimorphism of metabolic and vascular dysfunction in aged mice and those lacking the sphingosine 1-phosphate receptor 3. Exp Gerontol 2017; 99:87-97. [DOI: 10.1016/j.exger.2017.09.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/18/2017] [Accepted: 09/19/2017] [Indexed: 11/23/2022]
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27
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Estrogenic vascular effects are diminished by chronological aging. Sci Rep 2017; 7:12153. [PMID: 28939871 PMCID: PMC5610317 DOI: 10.1038/s41598-017-12153-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/07/2017] [Indexed: 12/22/2022] Open
Abstract
The beneficial role of estrogen in the vascular system may be due, in part, through reduction of peripheral vascular resistance. The use of estrogen therapy to prevent cardiovascular disease in post-menopausal women remains contentious. This study investigated the influence of aging and the menopause on the acute vasodilatory effects of estrogen using ex vivo human and murine resistance arteries. Vessels were obtained from young (2.9 ± 0.1 months) and aged (24.2 ± 0.1 and 28.9 ± 0.3 months) female mice and pre- (42.3 ± 0.5 years) and post-menopausal (61.9 ± 0.9 years) women. Aging was associated with profound structural alterations of murine uterine arteries, including the occurrence of outward hypertrophic remodeling and increased stiffness. Endothelial and smooth muscle function were diminished in uterine (and tail) arteries from aged mice and post-menopausal women. The acute vasodilatory effects of 17β-estradiol (non-specific estrogen receptor (ER) agonist), PPT (ERα-specific agonist) and DPN (ERβ-specific agonist) on resistance arteries were attenuated by aging and the menopause. However, the impairment of estrogenic relaxation was evident after the occurrence of age-related endothelial dysfunction and diminished distensibility. The data indicate, therefore, that chronological resistance arterial aging is a prominent factor leading to weakened vasodilatory action of estrogenic compounds.
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28
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Popova A, Tsvirkun D, Dolgov O, Anokhin K, Alberts J, Lagereva E, Custaud MA, Gauquelin-Koch G, Vinogradova O, Andreev-Andrievskiy A. Adaptation to a blood pressure telemetry system revealed by measures of activity, agility and operant learning in mice. J Pharmacol Toxicol Methods 2017; 85:29-37. [DOI: 10.1016/j.vascn.2017.02.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Revised: 01/04/2017] [Accepted: 02/02/2017] [Indexed: 02/02/2023]
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29
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Tykocki NR, Boerman EM, Jackson WF. Smooth Muscle Ion Channels and Regulation of Vascular Tone in Resistance Arteries and Arterioles. Compr Physiol 2017; 7:485-581. [PMID: 28333380 DOI: 10.1002/cphy.c160011] [Citation(s) in RCA: 222] [Impact Index Per Article: 31.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Vascular tone of resistance arteries and arterioles determines peripheral vascular resistance, contributing to the regulation of blood pressure and blood flow to, and within the body's tissues and organs. Ion channels in the plasma membrane and endoplasmic reticulum of vascular smooth muscle cells (SMCs) in these blood vessels importantly contribute to the regulation of intracellular Ca2+ concentration, the primary determinant of SMC contractile activity and vascular tone. Ion channels provide the main source of activator Ca2+ that determines vascular tone, and strongly contribute to setting and regulating membrane potential, which, in turn, regulates the open-state-probability of voltage gated Ca2+ channels (VGCCs), the primary source of Ca2+ in resistance artery and arteriolar SMCs. Ion channel function is also modulated by vasoconstrictors and vasodilators, contributing to all aspects of the regulation of vascular tone. This review will focus on the physiology of VGCCs, voltage-gated K+ (KV) channels, large-conductance Ca2+-activated K+ (BKCa) channels, strong-inward-rectifier K+ (KIR) channels, ATP-sensitive K+ (KATP) channels, ryanodine receptors (RyRs), inositol 1,4,5-trisphosphate receptors (IP3Rs), and a variety of transient receptor potential (TRP) channels that contribute to pressure-induced myogenic tone in resistance arteries and arterioles, the modulation of the function of these ion channels by vasoconstrictors and vasodilators, their role in the functional regulation of tissue blood flow and their dysfunction in diseases such as hypertension, obesity, and diabetes. © 2017 American Physiological Society. Compr Physiol 7:485-581, 2017.
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Affiliation(s)
- Nathan R Tykocki
- Department of Pharmacology, University of Vermont, Burlington, Vermont, USA
| | - Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri, USA
| | - William F Jackson
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan, USA
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30
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Siamwala JH, Macias BR, Lee PC, Hargens AR. Gender differences in tibial microvascular flow responses to head down tilt and lower body negative pressure. Physiol Rep 2017; 5:5/4/e13143. [PMID: 28242824 PMCID: PMC5328775 DOI: 10.14814/phy2.13143] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/05/2017] [Accepted: 01/08/2017] [Indexed: 11/24/2022] Open
Abstract
The purpose of the investigation was to study lower body negative pressure recovery in response to head down tilt position in men and women. The study examined the primary hypothesis that tibial bone microvascular flow responses to HDT and lower body negative pressure (LBNP) differ in women and men. Nine women and nine men between 20 to 30 years of age participated in the study. Tibial microvascular flow, head and tibial oxygenation and calf circumference were measured using photoplethysmography (PPG), near‐infrared spectroscopy (NIRS) and strain gauge plethysmography (SGP), respectively, during sitting (control baseline), supine, 15° HDT, and 15° HDT with 25 mmHg LBNP. Tibial microvascular flow with HDT increased by 57% from supine position (from 1.4V ± 0.7 to 2.2V ± 1.0 HDT; ANOVA P < 0.05) in men but there is no significant difference between supine and HDT in women. Ten minutes of LBNP during 15oHDT restored tibial bone microvascular flows to supine levels, (from 2.2V±1.0 HDT to 1.1V ± 0.7 supine; ANOVA P < 0.05) in men but not in women. These data support the concept that there are gender specific microvascular responses to a fluid‐shift countermeasure such as LBNP. Thus, gender differences should be considered while developing future countermeasure strategies to headward fluid shifts in microgravity.
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Affiliation(s)
- Jamila H Siamwala
- Department of Orthopedic Surgery, University of California, San Diego, California
| | - Brandon R Macias
- Department of Orthopedic Surgery, University of California, San Diego, California
| | - Paul C Lee
- Department of Orthopedic Surgery, University of California, San Diego, California
| | - Alan R Hargens
- Department of Orthopedic Surgery, University of California, San Diego, California
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31
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Washio T, Sasaki H, Ogoh S. Transcranial Doppler-determined change in posterior cerebral artery blood flow velocity does not reflect vertebral artery blood flow during exercise. Am J Physiol Heart Circ Physiol 2017; 312:H827-H831. [PMID: 28188214 DOI: 10.1152/ajpheart.00676.2016] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2016] [Revised: 01/30/2017] [Accepted: 01/31/2017] [Indexed: 11/22/2022]
Abstract
We examined whether a change in posterior cerebral artery flow velocity (PCAv) reflected the posterior cerebral blood flow in healthy subjects during both static and dynamic exercise. PCAv and vertebral artery (VA) blood flow, as an index of posterior cerebral blood flow, were continuously measured during an exercise trial using transcranial Doppler (TCD) ultrasonography and Doppler ultrasound, respectively. Static handgrip exercise significantly increased both PCAv and VA blood flow. Increasing intensity of dynamic exercise further increased VA blood flow from moderate exercise, while PCAv decreased to almost resting level. During both static and dynamic exercise, the PCA cerebrovascular conductance (CVC) index significantly decreased from rest (static and high-intensity dynamic exercise, -11.5 ± 12.2% and -18.0 ± 16.8%, means ± SD, respectively) despite no change in the CVC of VA. These results indicate that vasoconstriction occurred at PCA but not VA during exercise-induced hypertension. This discrepancy in vascular response to exercise between PCA and VA may be due to different cerebral arterial characteristics. Therefore, to determine the effect of exercise on posterior cerebral circulation, at least, we need to carefully consider which cerebral artery to measure, regardless of exercise mode.NEW & NOTEWORTHY We examined whether transcranial Doppler-determined flow velocity in the posterior cerebral artery can be used as an index of cerebral blood flow during exercise. However, the changes in posterior cerebral artery flow velocity during exercise do not reflect vertebral artery blood flow.
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Affiliation(s)
- Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-shi, Japan
| | - Hiroyuki Sasaki
- Department of Biomedical Engineering, Toyo University, Kawagoe-shi, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-shi, Japan
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32
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Jensen LJ, Nielsen MS, Salomonsson M, Sørensen CM. T-type Ca 2+ channels and autoregulation of local blood flow. Channels (Austin) 2017; 11:183-195. [PMID: 28055302 DOI: 10.1080/19336950.2016.1273997] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
L-type voltage gated Ca2+ channels are considered to be the primary source of calcium influx during the myogenic response. However, many vascular beds also express T-type voltage gated Ca2+ channels. Recent studies suggest that these channels may also play a role in autoregulation. At low pressures (40-80 mmHg) T-type channels affect myogenic responses in cerebral and mesenteric vascular beds. T-type channels also seem to be involved in skeletal muscle autoregulation. This review discusses the expression and role of T-type voltage gated Ca2+ channels in the autoregulation of several different vascular beds. Lack of specific pharmacological inhibitors has been a huge challenge in the field. Now the research has been strengthened by genetically modified models such as mice lacking expression of T-type voltage gated Ca2+ channels (CaV3.1 and CaV3.2). Hopefully, these new tools will help further elucidate the role of voltage gated T-type Ca2+ channels in autoregulation and vascular function.
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Affiliation(s)
- Lars Jørn Jensen
- a Departments of Veterinary Clinical and Animal Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Morten Schak Nielsen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Max Salomonsson
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
| | - Charlotte Mehlin Sørensen
- b Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Copenhagen , Denmark
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33
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Ogoh S, Washio T, Sasaki H, Petersen LG, Secher NH, Sato K. Coupling between arterial and venous cerebral blood flow during postural change. Am J Physiol Regul Integr Comp Physiol 2016; 311:R1255-R1261. [DOI: 10.1152/ajpregu.00325.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/28/2016] [Accepted: 10/28/2016] [Indexed: 11/22/2022]
Abstract
In supine humans the main drainage from the brain is through the internal jugular vein (IJV), but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral circulation, this study addressed both arterial and venous flow responses in the “anterior” and “posterior” parts of the brain when nine healthy subjects (5 men) were seated and flow was manipulated by hyperventilation and inhalation of 6% carbon dioxide (CO2). From a supine to a seated position, both internal carotid artery (ICA) and IJV blood flow decreased ( P = 0.004 and P = 0.002), while vertebral artery (VA) flow did not change ( P = 0.348) and VV flow increased ( P = 0.024). In both supine and seated positions the ICA response to manipulation of end-tidal CO2 tension was reflected in IJV ( r = 0.645 and r = 0.790, P < 0.001) and VV blood flow ( r = 0.771 and r = 0.828, P < 0.001). When seated, the decrease in ICA blood flow did not affect venous outflow, but the decrease in IJV blood flow was associated with the increase in VV blood flow ( r = 0.479, P = 0.044). In addition, the increase in VV blood flow when seated was reflected in VA blood flow ( r = 0.649, P = 0.004), and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r = 0.551, P = 0.004; seated, r = 0.612, P < 0001). These results support that VV compensates for the reduction in IJV blood flow when seated and that VV may influence VA blood flow.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Hiroyuki Sasaki
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Lonnie G. Petersen
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels H. Secher
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Kohei Sato
- Research Institute of Physical Fitness, Japan Women’s College of Physical Education, Tokyo, Japan; and
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34
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Ogoh S, Sørensen H, Hirasawa A, Sasaki H, Washio T, Hashimoto T, Bailey DM, Secher NH. Dynamic cerebral autoregulation is unrelated to decrease in external carotid artery blood flow during acute hypotension in healthy young men. Exp Physiol 2016; 101:1040-9. [PMID: 27228963 DOI: 10.1113/ep085772] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 05/19/2016] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Dynamic cerebral autoregulation (CA) is impaired by sympathetic blockade, and the external carotid artery (ECA) vascular bed may prevent adequate internal carotid artery blood flow. We examined whether α1 -receptor blockade-induced attenuation of dynamic CA is related to reduced ECA vasoconstriction. What is the main finding and its importance? α1 -Receptor blockade attenuated dynamic CA, but in contrast to our hypothesis did not affect the ECA blood flow response to acute hypotension. These findings suggest that the recovery of cerebral blood flow during acute hypotension is unrelated to vasoconstriction within the ECA territory. External carotid artery (ECA) vasoconstriction may defend internal carotid artery (ICA) blood flow during acute hypotension. We hypothesized that the α1 -receptor blockade-induced delay in ICA recovery to the baseline level from acute hypoperfusion is related to attenuated ECA vasoconstriction. The ICA and ECA blood flow were determined by duplex ultrasound during thigh-cuff release-induced acute hypotension while the α1 -receptor blocker prazosin [1 mg (20 kg)(-1) ] was administered to nine seated young healthy men. Both ICA (mean ± SD; by 17 ± 8%, P = 0.005) and ECA (by 37 ± 15%, P < 0.001) blood flow decreased immediately after occluded thigh-cuff release, with a more rapid ICA blood flow recovery to the baseline level (9 ± 5 s) than for the ECA blood flow (17 ± 5 s; P = 0.019). The ICA blood flow recovery from hypoperfusion was delayed with prazosin (17 ± 4 s versus control 9 ± 5 s, P = 0.006), whereas ECA recovery remained unchanged (P = 0.313) despite a similar reduction in mean arterial pressure (-20 ± 4 mmHg versus control -23 ± 7 mmHg, P = 0.148). These findings suggest that α1 -receptor blockade-induced attenuation of the ICA blood flow response to acute hypotension is unrelated to the reduction in ECA blood flow. The sympathetic nervous system via the ECA vascular bed does not contribute to dynamic CA during acute hypotension.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Henrik Sørensen
- The Copenhagen Muscle Research Centre, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ai Hirasawa
- Advanced Triage Team, Kyorin University School of Medicine, Mitaka-Shi, Tokyo, Japan
| | - Hiroyuki Sasaki
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-Shi, Saitama, Japan
| | - Takeshi Hashimoto
- Graduate School of Sport and Health Science, Ritsumeikan University, Shiga, Japan
| | - Damian M Bailey
- Neurovascular Research Laboratory, Research Institute of Health and Wellbeing, Faculty of Life Sciences and Education, University of South Wales, UK
| | - Niels H Secher
- The Copenhagen Muscle Research Centre, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
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Feldman RD, Ding Q, Hussain Y, Limbird LE, Pickering JG, Gros R. Aldosterone mediates metastatic spread of renal cancer
via
the G protein‐coupled estrogen receptor (GPER). FASEB J 2016; 30:2086-96. [DOI: 10.1096/fj.15-275552] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Accepted: 11/09/2015] [Indexed: 01/20/2023]
Affiliation(s)
- Ross D. Feldman
- Discipline of MedicineMemorial University of NewfoundlandSt. John'sNewfoundland and LabradorCanada
- Molecular Medicine Group, Robarts Research InstituteLondonOntarioCanada
| | - Qingming Ding
- Discipline of MedicineMemorial University of NewfoundlandSt. John'sNewfoundland and LabradorCanada
- Molecular Medicine Group, Robarts Research InstituteLondonOntarioCanada
| | - Yasin Hussain
- Molecular Medicine Group, Robarts Research InstituteLondonOntarioCanada
| | - Lee E. Limbird
- Department of Life and Physical SciencesFisk UniversityNashvilleTennesseeUSA
| | | | - Robert Gros
- Molecular Medicine Group, Robarts Research InstituteLondonOntarioCanada
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Long Lasting Microvascular Tone Alteration in Rat Offspring Exposed In Utero to Maternal Hyperglycaemia. PLoS One 2016; 11:e0146830. [PMID: 26756337 PMCID: PMC4710502 DOI: 10.1371/journal.pone.0146830] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 12/22/2015] [Indexed: 12/18/2022] Open
Abstract
Epidemiologic studies have demonstrated that cardiovascular risk is not only determined by conventional risk factors in adulthood, but also by early life events which may reprogram vascular function. To evaluate the effect of maternal diabetes on fetal programming of vascular tone in offspring and its evolution during adulthood, we investigated vascular reactivity of third order mesenteric arteries from diabetic mother offspring (DMO) and control mother offspring (CMO) aged 3 and 18 months. In arteries isolated from DMO the relaxation induced by prostacyclin analogues was reduced in both 3- and 18-month old animals although endothelium (acetylcholine)-mediated relaxation was reduced in 18-month old DMO only. Endothelium-independent (sodium nitroprusside) relaxation was not affected. Pressure-induced myogenic tone, which controls local blood flow, was reduced in 18-month old CMO compared to 3-month old CMO. Interestingly, myogenic tone was maintained at a high level in 18-month old DMO even though agonist-induced vasoconstriction was not altered. These perturbations, in 18-months old DMO rats, were associated with an increased pMLC/MLC, pPKA/PKA ratio and an activated RhoA protein. Thus, we highlighted perturbations in the reactivity of resistance mesenteric arteries in DMO, at as early as 3 months of age, followed by the maintenance of high myogenic tone in older rats. These modifications are in favour of excessive vasoconstrictor tone. These results evidenced a fetal programming of vascular functions of resistance arteries in adult rats exposed in utero to maternal diabetes, which could explain a re-setting of vascular functions and, at least in part, the occurrence of hypertension later in life.
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No apparent role for T-type Ca²⁺ channels in renal autoregulation. Pflugers Arch 2015; 468:541-50. [PMID: 26658945 DOI: 10.1007/s00424-015-1770-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/03/2015] [Indexed: 10/22/2022]
Abstract
Renal autoregulation protects glomerular capillaries against increases in renal perfusion pressure (RPP). In the mesentery, both L- and T-type calcium channels are involved in autoregulation. L-type calcium channels participate in renal autoregulation, but the role of T-type channels is not fully elucidated due to lack of selective pharmacological inhibitors. The role of T- and L-type calcium channels in the response to acute increases in RPP in T-type channel knockout mice (CaV3.1) and normo- and hypertensive rats was examined. Changes in afferent arteriolar diameter in the kidneys from wild-type and CaV3.1 knockout mice were assessed. Autoregulation of renal blood flow was examined during acute increases in RPP in normo- and hypertensive rats under pharmacological blockade of T- and L-type calcium channels using mibefradil (0.1 μM) and nifedipine (1 μM). In contrast to the results from previous pharmacological studies, genetic deletion of T-type channels CaV3.1 did not affect renal autoregulation. Pharmacological blockade of T-type channels using concentrations of mibefradil which specifically blocks T-type channels also had no effect in wild-type or knockout mice. Blockade of L-type channels significantly attenuated renal autoregulation in both strains. These findings are supported by in vivo studies where blockade of T-type channels had no effect on changes in the renal vascular resistance after acute increases in RPP in normo- and hypertensive rats. These findings show that genetic deletion of T-type channels CaV3.1 or treatment with low concentrations of mibefradil does not affect renal autoregulation. Thus, T-type calcium channels are not involved in renal autoregulation in response to acute increases in RPP.
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Shih AM, Varghese L, Bittar A, Park SH, Chung JM, Shin OH. Dysregulation of Norepinephrine Release in the Absence of Functional Synaptotagmin 7. J Cell Biochem 2015; 117:1446-53. [PMID: 27043247 DOI: 10.1002/jcb.25436] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2015] [Accepted: 11/10/2015] [Indexed: 01/28/2023]
Abstract
Synaptotagmin 7 (Syt7) is expressed in cardiac sympathetic nerve terminals where norepinephrine (NE) is released in both Ca(2+)-dependent exocytosis and Ca(2+)-independent norepinephrine transporter (NET)-mediated overflow. The role of Syt7 in the regulation of NE release from cardiac sympathetic nerve terminals is tested by employing a Syt7 knock-in mouse line that expresses a non-functional mutant form of Syt7. In cardiac sympathetic nerve terminals prepared from these Syt7 knock-in mice, the Ca(2+)-dependent component of NE release was diminished. However, these terminals displayed upregulated function of NET (∼130% of controls) and a significant increase in Ca(2+)-independent NE overflow (∼140% of controls), which is greater than the Ca(2+)-dependent component of NE exocytosis occurring in wild-type controls. Consistent with a significant increase in NE overflow, the Syt7 knock-in mice showed significantly higher blood pressures compared to those of littermate wild-type and heterozygous mice. Our results indicate that the lack of functional Syt7 dysregulates NE release from cardiac sympathetic nerve terminals.
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Affiliation(s)
- Alvin M Shih
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Lincy Varghese
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Alice Bittar
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Sung-Hoon Park
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Jin Mo Chung
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
| | - Ok-Ho Shin
- Department of Neuroscience and Cell Biology, University of Texas Medical Branch, Galveston, Texas, 77555
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Boerman EM, Segal SS. Depressed perivascular sensory innervation of mouse mesenteric arteries with advanced age. J Physiol 2015; 594:2323-38. [PMID: 26010764 DOI: 10.1113/jp270710] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Accepted: 05/15/2015] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS The dilatory role for sensory innervation of mesenteric arteries (MAs) is impaired in Old (∼24 months) versus Young (∼4 months) mice. We investigated the nature of this impairment in isolated pressurized MAs. With perivascular sensory nerve stimulation, dilatation and inhibition of sympathetic vasoconstriction observed in Young MAs were lost in Old MAs along with impaired dilatation to calcitonin gene-related peptide (CGRP). Inhibiting NO and prostaglandin synthesis increased CGRP EC50 in Young and Old MAs. Endothelial denudation attenuated dilatation to CGRP in Old MAs yet enhanced dilatation to CGRP in Young MAs while abolishing all dilatations to ACh. In Old MAs, sensory nerve density was reduced and RAMP1 (CGRP receptor component) associated with nuclear regions of endothelial cells in a manner not seen in Young MAs or in smooth muscle cells of either age. With advanced age, loss of dilatory signalling mediated through perivascular sensory nerves may compromise perfusion of visceral organs. ABSTRACT Vascular dysfunction and sympathetic nerve activity increase with advancing age. In the gut, blood flow is governed by perivascular sensory and sympathetic nerves but little is known of how their functional role is affected by advanced age. We tested the hypothesis that functional sensory innervation of mesenteric arteries (MAs) is impaired for Old (24 months) versus Young (4 months) C57BL/6 male mice. In cannulated pressurized MAs preconstricted 50% with noradrenaline and treated with guanethidine (to inhibit sympathetic neurotransmission), perivascular nerve stimulation (PNS) evoked dilatation in Young but not Old MAs while dilatations to ACh were not different between age groups. In Young MAs, capsaicin (to inhibit sensory neurotransmission) blocked dilatation and increased constriction during PNS. With no difference in efficacy, the EC50 of CGRP as a vasodilator was ∼6-fold greater in Old versus Young MAs. Inhibiting nitric oxide (l-NAME) and prostaglandin (indomethacin) synthesis increased CGRP EC50 in both age groups. Endothelial denudation reduced the efficacy of dilatation to CGRP by ∼30% in Old MAs yet increased this efficacy ∼15% in Young MAs while all dilatations to ACh were abolished. Immunolabelling revealed reduced density of sensory (CGRP) but not sympathetic (tyrosine hydroxylase) innervation for Old versus Young MAs. Whereas the distribution of CGRP receptor proteins was similar in SMCs, RAMP1 associated with nuclear regions of endothelial cells of Old but not Young MAs. With advanced age, the loss of sensory nerve function and diminished effectiveness of CGRP as a vasodilator is multifaceted and may adversely affect splanchnic perfusion.
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Affiliation(s)
- Erika M Boerman
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, 65212, USA.,Dalton Cardiovascular Research Center, Columbia, MO, 65211, USA
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Tutunea-Fatan E, Caetano FA, Gros R, Ferguson SSG. GRK2 targeted knock-down results in spontaneous hypertension, and altered vascular GPCR signaling. J Biol Chem 2015; 290:5141-5155. [PMID: 25561731 DOI: 10.1074/jbc.m114.615658] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Hypertension, elevated arterial pressure, occurs as the consequence of increased peripheral resistance. G protein-coupled receptors (GPCRs) contribute to the regulation of vasodilator and vasoconstrictor responses, and their activity is regulated by a family of GPCR kinases (GRKs). GRK2 expression is increased in hypertension and this facilitates the development of the hypertensive state by increasing the desensitization of GPCRs important for vasodilation. We demonstrate here, that genetic knockdown of GRK2 using a small hairpin (sh) RNA results in altered vascular reactivity and the development of hypertension between 8-12 weeks of age in shGRK2 mice due to enhanced Gαq/11 signaling. Vascular smooth muscle cells (VSMCs) cultured from shGRK2 knockdown mice show increases in GPCR-mediated Gαs and Gαq/11 signaling, as the consequence of reduced GRK2-mediated desensitization. In addition, agonists and biased agonists exhibited age-dependent alterations in ERK1/2 and Akt signaling, as well as cell proliferation and migration responses in shGRK2 knockdown VSMCs when cultured from mice that are either 3 months or 6 months of age. Changes in angiotensin II-stimulated ERK1/2 phosphorylation are observed in VSMCs derived from 6-week-old shGRK2 mice prior to the development of the hypertensive phenotype. Thus, our findings indicate that the balance between mechanisms regulating vascular tone are shifted to favor vasoconstriction in the absence of GRK2 expression and that this leads to the age-dependent development of hypertension, as a consequence of global alterations in GPCR signaling. Consequently, therapeutic strategies that target GRK2 activity, not expression, may be more effective for the treatment of hypertension.
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Affiliation(s)
- Elena Tutunea-Fatan
- From the J. Allyn Taylor Centre for Cell Biology,; Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5K8, Canada
| | | | - Robert Gros
- From the J. Allyn Taylor Centre for Cell Biology,; Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5K8, Canada; Vascular Biology Group, Robarts Research Institute, and; Departments of Medicine,.
| | - Stephen S G Ferguson
- From the J. Allyn Taylor Centre for Cell Biology,; Physiology and Pharmacology, University of Western Ontario, London, Ontario N6A 5K8, Canada.
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Ohanian J, Liao A, Forman SP, Ohanian V. Age-related remodeling of small arteries is accompanied by increased sphingomyelinase activity and accumulation of long-chain ceramides. Physiol Rep 2014; 2:2/5/e12015. [PMID: 24872355 PMCID: PMC4098743 DOI: 10.14814/phy2.12015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
The structure and function of large arteries alters with age leading to increased risk of cardiovascular disease. Age‐related large artery remodeling and arteriosclerosis is associated with increased collagen deposition, inflammation, and endothelial dysfunction. Bioactive sphingolipids are known to regulate these processes, and are also involved in aging and cellular senescence. However, less is known about age‐associated alterations in small artery morphology and function or whether changes in arterial sphingolipids occur in aging. We show that mesenteric small arteries from old sheep have increased lumen diameter and media thickness without a change in media to lumen ratio, indicative of outward hypertrophic remodeling. This remodeling occurred without overt changes in blood pressure or pulse pressure indicating it was a consequence of aging per se. There was no age‐associated change in mechanical properties of the arteries despite an increase in total collagen content and deposition of collagen in a thickened intima layer in arteries from old animals. Analysis of the sphingolipid profile showed an increase in long‐chain ceramide (C14–C20), but no change in the levels of sphingosine or sphingosine‐1‐phosphate in arteries from old compared to young animals. This was accompanied by a parallel increase in acid and neutral sphingomyelinase activity in old arteries compared to young. This study demonstrates remodeling of small arteries during aging that is accompanied by accumulation of long‐chain ceramides. This suggests that sphingolipids may be important mediators of vascular aging. In this study, we have investigated remodeling of small arteries in a large animal model of aging, the sheep. We show that there is age‐related formation of neointima and increased collagen deposition that is accompanied by changes in sphingolipid metabolism resulting in ceramide accumulation in the tissues. These are the first data implicating sphingolipids as important mediators of vascular aging in small arteries. Given that aging is a major risk factor for cardiovascular disease, our study opens a new area for further research into the mechanisms that underlie vascular remodeling in aging.
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Affiliation(s)
- Jacqueline Ohanian
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - Aiyin Liao
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - Simon P Forman
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
| | - Vasken Ohanian
- Institute of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, Manchester, UK
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Krishnamoorthy G, Sonkusare SK, Heppner TJ, Nelson MT. Opposing roles of smooth muscle BK channels and ryanodine receptors in the regulation of nerve-evoked constriction of mesenteric resistance arteries. Am J Physiol Heart Circ Physiol 2014; 306:H981-8. [PMID: 24508642 DOI: 10.1152/ajpheart.00866.2013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In depolarized smooth muscle cells of pressurized cerebral arteries, ryanodine receptors (RyRs) generate "Ca2+ sparks" that activate large-conductance, Ca2+ -, and voltage-sensitive potassium (BK) channels to oppose pressure-induced (myogenic) constriction. Here, we show that BK channels and RyRs have opposing roles in the regulation of arterial tone in response to sympathetic nerve activation by electrical field stimulation. Inhibition of BK channels with paxilline increased both myogenic and nerve-induced constrictions of pressurized, resistance-sized mesenteric arteries from mice. Inhibition of RyRs with ryanodine increased myogenic constriction, but it decreased nerve-evoked constriction along with a reduction in the amplitude of nerve-evoked increases in global intracellular Ca2+. In the presence of L-type voltage-dependent Ca2+ channel (VDCC) antagonists, nerve stimulation failed to evoke a change in arterial diameter, and BK channel and RyR inhibitors were without effect, suggesting that nerve- induced constriction is dependent on activation of VDCCs. Collectively, these results indicate that BK channels and RyRs have different roles in the regulation of myogenic versus neurogenic tone: whereas BK channels and RyRs act in concert to oppose myogenic vasoconstriction, BK channels oppose neurogenic vasoconstriction and RyRs augment it. A scheme for neurogenic vasoregulation is proposed in which RyRs act in conjunction with VDCCs to regulate nerve-evoked constriction in mesenteric resistance arteries.
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Chaston DJ, Baillie BK, Grayson TH, Courjaret RJ, Heisler JM, Lau KA, Machaca K, Nicholson BJ, Ashton A, Matthaei KI, Hill CE. Polymorphism in endothelial connexin40 enhances sensitivity to intraluminal pressure and increases arterial stiffness. Arterioscler Thromb Vasc Biol 2013; 33:962-70. [PMID: 23471232 DOI: 10.1161/atvbaha.112.300957] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
OBJECTIVE To determine whether impairment of endothelial connexin40 (Cx40), an effect that can occur in hypertension and aging, contributes to the arterial dysfunction and stiffening in these conditions. APPROACH AND RESULTS A new transgenic mouse strain, expressing a mutant Cx40, (Cx40T202S), specifically in the vascular endothelium, has been developed and characterized. This mutation produces nonfunctional hemichannels, whereas gap junctions containing the mutant are electrically, but not chemically, patent. Mesenteric resistance arteries from Cx40T202S mice showed increased sensitivity of the myogenic response to intraluminal pressure in vitro, compared with wild-type mice, whereas transgenic mice overexpressing native Cx40 (Cx40Tg) showed reduced sensitivity. In control and Cx40Tg mice, the sensitivity to pressure of myogenic constriction was modulated by both NO and endothelium-derived hyperpolarization; however, the endothelium-derived hyperpolarization component was absent in Cx40T202S arteries. Analysis of passive mechanical properties revealed that arterial stiffness was enhanced in vessels from Cx40T202S mice, but not in wild-type or Cx40Tg mice. CONCLUSIONS Introduction of a mutant form of Cx40 in the endogenous endothelial Cx40 population prevents endothelium-derived hyperpolarization activation during myogenic constriction, enhancing sensitivity to intraluminal pressure and increasing arterial stiffness. We conclude that genetic polymorphisms in endothelial Cx40 can contribute to the pathogenesis of arterial disease.
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Affiliation(s)
- Daniel J Chaston
- John Curtin School of Medical Research, The Australian National University, Bldg 131 Garran Rd, Acton Australian Capital Territory 0200 Australia.
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Westcott EB, Segal SS. Ageing alters perivascular nerve function of mouse mesenteric arteries in vivo. J Physiol 2013; 591:1251-63. [PMID: 23247111 PMCID: PMC3607869 DOI: 10.1113/jphysiol.2012.244483] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 12/10/2012] [Indexed: 12/16/2022] Open
Abstract
Abstract Mesenteric arteries (MAs) are studied widely in vitro but little is known of their reactivity in vivo. Transgenic animals have enabled Ca(2+) signalling to be studied in isolated MAs but the reactivity of these vessels in vivo is undefined. We tested the hypothesis that ageing alters MA reactivity to perivascular nerve stimulation (PNS) and adrenoreceptor (AR) activation during blood flow control. First- (1A), second- (2A) and third-order (3A) MAs of pentobarbital-anaesthetized Young (3-6 months) and Old (24-26 months) male and female Cx40(BAC)-GCaMP2 transgenic mice (C57BL/6 background; positive or negative for the GCaMP2 transgene) were studied with intravital microscopy. A segment of jejunum was exteriorized and an MA network was superfused with physiological salt solution (pH 7.4, 37°C). Resting tone was 10% in MAs of Young and Old mice; diameters were ∼5% (1A), 20% (2A) and 40% (3A) smaller (P 0.05) in Old mice. Throughout MA networks, vasoconstriction increased with PNS frequency (1-16 Hz) but was ∼20% less in Young vs. Old mice (P 0.05) and was inhibited by tetrodotoxin (1 μm). Capsaicin (10 μm; to inhibit sensory nerves) enhanced MA constriction to PNS (P 0.05) by ∼20% in Young but not Old mice. Phenylephrine (an α1AR agonist) potency was greater in Young mice (P 0.05) with similar efficacy (∼60% constriction) across ages and MA branches. Constrictions to UK14304 (an α2AR agonist) were less (∼20%; P 0.05) and were unaffected by ageing. Irrespective of sex or transgene expression, ageing consistently reduced the sensitivity of MAs to α1AR vasoconstriction while blunting the attenuation of sympathetic vasoconstriction by sensory nerves. These findings imply substantive alterations in splanchnic blood flow control with ageing.
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Affiliation(s)
- Erika B Westcott
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO 65212, USA
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Chan MV, Bubb KJ, Noyce A, Villar IC, Duchene J, Hobbs AJ, Scotland RS, Ahluwalia A. Distinct endothelial pathways underlie sexual dimorphism in vascular auto-regulation. Br J Pharmacol 2013; 167:805-17. [PMID: 22540539 DOI: 10.1111/j.1476-5381.2012.02012.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND AND PURPOSE Pre-menopausal females have a lower incidence of cardiovascular disease compared with age-matched males, implying differences in the mechanisms and pathways regulating vasoactivity. In small arteries, myogenic tone (constriction in response to raised intraluminal pressure) is a major determinant of vascular resistance. Endothelium-derived dilators, particularly NO, tonically moderate myogenic tone and, because the endothelium is an important target for female sex hormones, we investigated whether NO-mediated moderation of myogenic tone differed between the sexes. EXPERIMENTAL APPROACH Pressure-diameter or relaxation concentration-response curves to the NO donor spermine-NO or soluble guanylate cyclase (sGC) stimulation (BAY41-2272) were constructed before and following drug intervention in murine mesenteric resistance arteries. Hypotensive responses to activators of the NO-sGC pathway were determined. Quantitative PCR and Western blotting were used for expression analysis. KEY RESULTS NO synthase inhibition enhanced myogenic tone of arteries of both sexes while block of endothelium-derived hyperpolarizing factor (EDHF) enhanced responses in arteries of females only. Spermine-NO concentration-dependently relaxed mesenteric arteries isolated from either sex. However, while inhibition of sGC activity attenuated responses of arteries from male mice only, endothelial denudation attenuated responses of arteries from females only. BAY41-2272 and spermine-NO-induced vasodilatation and hypotension were greater in males than in females. CONCLUSIONS AND IMPLICATIONS NO moderated myogenic tone in arteries of male mice by a sGC-dependent pathway while EDHF was the predominant endothelial regulator in arteries of females. This is a potentially important sexual dimorphism in NO-mediated reactivity and further implicates EDHF as the predominant endothelial vasodilator in female resistance arteries.
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Affiliation(s)
- Melissa V Chan
- William Harvey Research Institute, Barts and The London Medical School, London, UK
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46
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Effect of aging on calcium signaling in C57Bl6J mouse cerebral arteries. Pflugers Arch 2012; 465:829-38. [DOI: 10.1007/s00424-012-1195-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2012] [Revised: 11/28/2012] [Accepted: 11/29/2012] [Indexed: 01/08/2023]
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47
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Gombos RB, Brown JC, Teefy J, Gibeault RL, Conn KL, Schang LM, Hemmings DG. Vascular dysfunction in young, mid-aged and aged mice with latent cytomegalovirus infections. Am J Physiol Heart Circ Physiol 2012; 304:H183-94. [PMID: 23125213 DOI: 10.1152/ajpheart.00461.2012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Human cytomegalovirus (HCMV) is associated with vascular diseases in both immunosuppressed and immunocompetent individuals. CMV infections cycle between active and latent phases throughout life. We and others have shown vascular dysfunction during active mouse CMV (mCMV) infections. Few studies have examined changes in physiology during latent CMV infections, particularly vascular responses or whether the negative effects of aging on vascular function and fertility will be exacerbated under these conditions. We measured vascular responses in intact mesenteric and uterine arteries dissected from young, mid-aged, and aged latently mCMV-infected (mCMV genomes are present but infectious virus is undetectable) and age-matched uninfected mice using a pressure myograph. We tested responses to the α(1)-adrenergic agonist phenylephrine, the nitric oxide donor sodium nitroprusside, and the endothelium-dependent vasodilator methacholine. In young latently mCMV-infected mice, vasoconstriction was increased and vasodilation was decreased in mesenteric arteries, whereas both vasoconstriction and vasodilation were increased in uterine arteries compared with those in age-matched uninfected mice. In reproductively active mid-aged latently infected mice, mesenteric arteries showed little change, whereas uterine arteries showed greatly increased vasoconstriction. These vascular effects may have contributed to the decreased reproductive success observed in mid-aged latently mCMV-infected compared with age-matched uninfected mice (16.7 vs. 46.7%, respectively). In aged latently infected mice, vasodilation is increased in mesenteric and uterine arteries likely to compensate for increased vasoconstriction to mediators other than phenylephrine. The novel results of this study show that even when active mCMV infections become undetectable, vascular dysfunction continues and differs with age and artery origin.
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Affiliation(s)
- R B Gombos
- Department of Obstetrics and Gynecology, University of Alberta, Edmonton, Alberta, Canada
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Hausman N, Martin J, Taggart MJ, Austin C. Age-related changes in the contractile and passive arterial properties of murine mesenteric small arteries are altered by caveolin-1 knockout. J Cell Mol Med 2012; 16:1720-30. [PMID: 21973085 PMCID: PMC3822685 DOI: 10.1111/j.1582-4934.2011.01457.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Accepted: 09/05/2011] [Indexed: 01/19/2023] Open
Abstract
Caveolin-1, an integral protein of caveolae, is associated with multiple cardiovascular signalling pathways. Caveolin-1 knockout (KO) mice have a reduced lifespan. As changes in artery structure and function are associated with ageing we have investigated the role of caveolin-1 ablation on age-related changes of small artery contractility and passive mechanical properties. Mesenteric small arteries isolated from 3 and 12-month wild-type (WT) and caveolin-1 KO mice were mounted on a pressure myograph and changes in passive and functional arterial properties were continuously monitored. In WT mice ageing was associated with a reduction in arterial contractility to noradrenaline which was reversed by inhibition of nitric oxide synthase with L-NNA. Similarly, in 3-month-old mice, caveolin-1 KO reduced contractility to noradrenaline by an L-NNA-sensitive mechanism. However, ageing in caveolin-1 KO mice was not associated with any further change in contractility. In WT mice ageing was associated with an increased passive arterial diameter and cross-sectional area (CSA), consistent with outward remodelling of the arterial wall, and a reduced arterial distensibility. Caveolin-1 ablation at 3 months of age resulted in similar changes in passive arterial properties to those observed with ageing in WT animals. However, ageing in caveolin-1 KO mice resulted in a reduced arterial CSA indicating different effects on passive structural characteristics from that observed in WT mice. Thus, caveolin-1 mice show abnormalities of small mesenteric artery function and passive mechanical characteristics indicative of premature vascular ageing. Moreover, caveolin-1 ablation modulates the age-related changes usually observed in mesenteric arteries of WT mice.
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Affiliation(s)
- Natasha Hausman
- Cardiovascular Research Group, University of ManchesterManchester, UK
| | - Julie Martin
- Institute of Cellular Medicine, Newcastle UniversityNewcastle-upon-Tyne, UK
| | - Michael J Taggart
- Institute of Cellular Medicine, Newcastle UniversityNewcastle-upon-Tyne, UK
| | - Clare Austin
- Cardiovascular Research Group, University of ManchesterManchester, UK
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van Drongelen J, Ploemen IHJ, Pertijs J, Gooi JH, Sweep FCGJ, Lotgering FK, Spaanderman MEA, Smits P. Aging attenuates the vasodilator response to relaxin. Am J Physiol Heart Circ Physiol 2011; 300:H1609-15. [DOI: 10.1152/ajpheart.00360.2010] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Relaxin, an insulin-like growth factor peptide, increases endothelium-dependent vasodilation and vascular compliance and decreases myogenic reactivity. These vascular effects significantly contribute to the physiological circulatory adaptations in pregnancy, particularly in the mesentery and kidney. Aging predisposes to vascular maladaptation and gestational hypertensive disease. We hypothesized that mild aging reduces the vascular responses to relaxin. In 20 young (10–12 wk) and 20 middle-aged (40–46 wk) female Wistar Hannover rats, vascular responses to chronic exposure of relaxin vs. placebo (5 days) were quantified in isolated mesenteric arteries and kidney. Vascular responses were evaluated using pressure-perfusion myograph, wire myograph, and an isolated perfused rat kidney model. Rxfp1 (relaxin family peptide) gene expression was determined by quantitative polymerase chain reaction. In young rats, relaxin stimulated nitric oxide (NO)-dependent flow-mediated vasodilation (2.67-fold, from 48 ± 9 to 18 ± 4 μl/min), reduced myogenic reactivity (from −1 ± 2 to 7 ± 3 μm/10 mmHg), and decreased mesenteric sensitivity to (28%, from 1.39 ± 0.08 to 1.78 ± 0.10 μM) but did not change compliance and renal perfusion flow (RPFF). In aged rats, relaxin did not affect any of the analyzed mesenteric or renal parameters. In aged compared with young placebo-treated rats, all mesenteric characteristics were comparable, while RPFF was lower (17%, from 6.9 ± 0.2 to 5.7 ± 0.1 ml·min−1·100 g−1) even though NO availability was comparable. Rxfp1 expression was not different among young and aged rats. Our findings suggest that moderate aging involves normal endothelial function but blunts the physiological endothelium-dependent and -independent vasodilator response to relaxin.
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Affiliation(s)
| | | | | | - Jonathan H. Gooi
- Department of Zoology, University of Melbourne, Melbourne, Australia
| | - Fred C. G. J. Sweep
- Laboratory Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands; and
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50
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Gombos RB, Hemmings DG. Differential effects on nitric oxide-mediated vasodilation in mesenteric and uterine arteries from cytomegalovirus-infected mice. Am J Physiol Heart Circ Physiol 2010; 299:H1124-34. [DOI: 10.1152/ajpheart.01113.2009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Chronic cytomegalovirus (CMV) infections are implicated in vascular diseases. Recently, we showed that an active mouse CMV (mCMV) infection in nonpregnant mice increased endothelial-dependent vasodilation in isolated mesenteric and uterine arteries. In late pregnancy, while increased vasodilation was found in mesenteric arteries from infected mice, there was a dramatic decrease in uterine arteries. Understanding the mechanisms for these vascular changes during CMV infections is important for pregnancy outcomes and long-term consequences of this chronic infection. Increased nitric oxide (NO) is implicated in CMV-associated atherosclerosis, and CMV replication is dependent on prostaglandin H synthase (PGHS) activity. Alternatively, CMV infections decrease NO under inflammatory conditions. We therefore hypothesized that changes in the contribution by NO or PGHS-induced vasodilators would explain the increased or decreased endothelial-dependent vasodilation in arteries from nonpregnant and late pregnant mice, respectively. We found that the contribution by NO to methacholine-induced vasodilation was significantly increased in mesenteric, but not uterine, arteries isolated from nonpregnant and pregnant mCMV-infected mice. Prostaglandin inhibition did not affect endothelial-dependent vasodilation in any group. Vasodilation responses to sodium nitroprusside, an NO donor, were increased in mesenteric and uterine arteries isolated only from mCMV-infected nonpregnant mice. These results explain the increased vasodilation responses observed in mesenteric arteries from mCMV-infected mice; however, the decreased vasodilation in uterine arteries from pregnant mice could not be explained by these mechanisms. Thus CMV infection affects the contribution of NO differently in endothelial-dependent vasodilation in pregnant compared with nonpregnant mice and also in the mesenteric compared with the uterine vascular bed.
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Affiliation(s)
| | - Denise G. Hemmings
- Obstetrics and Gynecology, and
- Medical Microbiology and Immunology, University of Alberta, Edmonton, Alberta, Canada
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