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Zhang YY, Li JZ, Xie HQ, Jin YX, Wang WT, Zhao B, Jia JM. High-resolution vasomotion analysis reveals novel arteriole physiological features and progressive modulation of cerebral vascular networks by stroke. J Cereb Blood Flow Metab 2024:271678X241258576. [PMID: 38820436 DOI: 10.1177/0271678x241258576] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 06/02/2024]
Abstract
Spontaneous cerebral vasomotion, characterized by ∼0.1 Hz rhythmic contractility, is crucial for brain homeostasis. However, our understanding of vasomotion is limited due to a lack of high-precision analytical methods to determine single vasomotion events at basal levels. Here, we developed a novel strategy that integrates a baseline smoothing algorithm, allowing precise measurements of vasodynamics and concomitant Ca2+ dynamics in mouse cerebral vasculature imaged by two-photon microscopy. We identified several previously unrecognized vasomotion properties under different physiological and pathological conditions, especially in ischemic stroke, which is a highly harmful brain disease that results from vessel occlusion. First, the dynamic characteristics between SMCs Ca2+ and corresponding arteriolar vasomotion are correlated. Second, compared to previous diameter-based estimations, our radius-based measurements reveal anisotropic vascular movements, enabling a more precise determination of the latency between smooth muscle cell (SMC) Ca2+ activity and vasoconstriction. Third, we characterized single vasomotion event kinetics at scales of less than 4 seconds. Finally, following pathological vasoconstrictions induced by ischemic stroke, vasoactive arterioles entered an inert state and persisted despite recanalization. In summary, we developed a highly accurate technique for analyzing spontaneous vasomotion, and our data suggested a potential strategy to reduce stroke damage by promoting vasomotion recovery.
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Affiliation(s)
- Yi-Yi Zhang
- College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang, China
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Jin-Ze Li
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Hui-Qi Xie
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Yu-Xiao Jin
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Wen-Tao Wang
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Bingrui Zhao
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
| | - Jie-Min Jia
- Key Laboratory of Growth Regulation and Translation Research of Zhejiang Province, School of Life Sciences, Westlake University, Hangzhou, China
- Laboratory of Neurovascular Biology, Institute of Basic Medical Sciences, Westlake Institute for Advanced Study, Hangzhou, China
- Westlake Laboratory of Life Sciences and Biomedicine, Hangzhou, China
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Gruenewald T, Seeman TE, Choo TH, Scodes J, Snyder C, Pavlicova M, Weinstein M, Schwartz JE, Mukkamala R, Sloan RP. Cardiovascular variability, sociodemographics, and biomarkers of disease: the MIDUS study. Front Physiol 2023; 14:1234427. [PMID: 37693005 PMCID: PMC10484414 DOI: 10.3389/fphys.2023.1234427] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 08/09/2023] [Indexed: 09/12/2023] Open
Abstract
Introduction: Like heart rate, blood pressure (BP) is not steady but varies over intervals as long as months to as short as consecutive cardiac cycles. This blood pressure variability (BPV) consists of regularly occurring oscillations as well as less well-organized changes and typically is computed as the standard deviation of multiple clinic visit-to-visit (VVV-BP) measures or from 24-h ambulatory BP recordings (ABPV). BP also varies on a beat-to-beat basis, quantified by methods that parse variation into discrete bins, e.g., low frequency (0.04-0.15 Hz, LF). However, beat-to-beat BPV requires continuous recordings that are not easily acquired. As a result, we know little about the relationship between LF-BPV and basic sociodemographic characteristics such as age, sex, and race and clinical conditions. Methods: We computed LF-BPV during an 11-min resting period in 2,118 participants in the Midlife in the US (MIDUS) study. Results: LF-BPV was negatively associated with age, greater in men than women, and unrelated to race or socioeconomic status. It was greater in participants with hypertension but unrelated to hyperlipidemia, hypertriglyceridemia, diabetes, elevated CRP, or obesity. LF-diastolic BPV (DBPV), but not-systolic BPV (SBPV), was negatively correlated with IL-6 and s-ICAM and positively correlated with urinary epinephrine and cortisol. Finally, LF-DBPV was negatively associated with mortality, an effect was rendered nonsignificant by adjustment by age but not other sociodemographic characteristics. Discussion: These findings, the first from a large, national sample, suggest that LF-BPV differs significantly from VVV-BP and ABPV. Confirming its relationship to sociodemographic risk factors and clinical outcomes requires further study with large and representative samples.
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Affiliation(s)
- Tara Gruenewald
- Department of Psychology, Chapman University, Orange, CA, United States
| | - Teresa E. Seeman
- David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States
| | - Tse-Hwei Choo
- Mental Health Data Science Division, New York State Psychiatric Institute, New York, NY, United States
| | - Jennifer Scodes
- Mental Health Data Science Division, New York State Psychiatric Institute, New York, NY, United States
| | - Clayton Snyder
- Mental Health Data Science Division, New York State Psychiatric Institute, New York, NY, United States
| | - Martina Pavlicova
- Department of Biostatistics, Mailman School of Public Health, Columbia University Irving Medical Center, New York, NY, United States
| | | | - Joseph E. Schwartz
- Renaissance School of Medicine, Stony Brook University, New York, NY, United States
- Department of Medicine, Columbia University Irving Medical Center, New York, NY, United States
| | - Ramakrishna Mukkamala
- Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, United States
| | - Richard P. Sloan
- Division of Behavioral Medicine, Department of Psychiatry, Columbia University Irving Medical Center, New York, NY, United States
- New York State Psychiatric Institute, New York, NY, United States
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Zharkikh EV, Loktionova YI, Fedorovich AA, Gorshkov AY, Dunaev AV. Assessment of Blood Microcirculation Changes after COVID-19 Using Wearable Laser Doppler Flowmetry. Diagnostics (Basel) 2023; 13:diagnostics13050920. [PMID: 36900064 PMCID: PMC10000665 DOI: 10.3390/diagnostics13050920] [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: 12/30/2022] [Revised: 02/20/2023] [Accepted: 02/24/2023] [Indexed: 03/05/2023] Open
Abstract
The present work is focused on the study of changes in microcirculation parameters in patients who have undergone COVID-19 by means of wearable laser Doppler flowmetry (LDF) devices. The microcirculatory system is known to play a key role in the pathogenesis of COVID-19, and its disorders manifest themselves long after the patient has recovered. In the present work, microcirculatory changes were studied in dynamics on one patient for 10 days before his disease and 26 days after his recovery, and data from the group of patients undergoing rehabilitation after COVID-19 were compared with the data from a control group. A system consisting of several wearable laser Doppler flowmetry analysers was used for the studies. The patients were found to have reduced cutaneous perfusion and changes in the amplitude-frequency pattern of the LDF signal. The obtained data confirm that microcirculatory bed dysfunction is present in patients for a long period after the recovery from COVID-19.
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Affiliation(s)
- Elena V. Zharkikh
- Research and Development Center of Biomedical Photonics, Orel State University, Komsomolskaya 95, Orel 302026, Russia
- Correspondence:
| | - Yulia I. Loktionova
- Research and Development Center of Biomedical Photonics, Orel State University, Komsomolskaya 95, Orel 302026, Russia
| | - Andrey A. Fedorovich
- Research and Development Center of Biomedical Photonics, Orel State University, Komsomolskaya 95, Orel 302026, Russia
- National Medical Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation, Petroverigsky 10, Moscow 101990, Russia
| | - Alexander Y. Gorshkov
- National Medical Research Center for Therapy and Preventive Medicine of the Ministry of Healthcare of the Russian Federation, Petroverigsky 10, Moscow 101990, Russia
| | - Andrey V. Dunaev
- Research and Development Center of Biomedical Photonics, Orel State University, Komsomolskaya 95, Orel 302026, Russia
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Anderson GK, Rickards CA. The potential therapeutic benefits of low frequency haemodynamic oscillations. J Physiol 2022; 600:3905-3919. [PMID: 35883272 PMCID: PMC9444954 DOI: 10.1113/jp282605] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Accepted: 07/22/2022] [Indexed: 11/08/2022] Open
Abstract
Haemodynamic oscillations occurring at frequencies below the rate of respiration have been observed experimentally for more than a century. Much of the research regarding these oscillations, observed in arterial pressure and blood flow, has focused on mechanisms of generation and methods of quantification. However, examination of the physiological role of these oscillations has been limited. Multiple studies have demonstrated that oscillations in arterial pressure and blood flow are associated with the protection in tissue oxygenation or functional capillary density during conditions of reduced tissue perfusion. There is also evidence that oscillatory blood flow can improve clearance of interstitial fluid, with a growing number of studies demonstrating a role for oscillatory blood flow to aid in clearance of debris from the brain. The therapeutic potential of these haemodynamic oscillations is an important new area of research which may have beneficial impact in treating conditions such as stroke, cardiac arrest, blood loss injuries, sepsis, or even Alzheimer's disease and vascular dementia.
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Affiliation(s)
- Garen K Anderson
- Cerebral & Cardiovascular Physiology Laboratory, Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
| | - Caroline A Rickards
- Cerebral & Cardiovascular Physiology Laboratory, Department of Physiology & Anatomy, University of North Texas Health Science Center, Fort Worth, TX, USA
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Thorn CE, Adio AO, Fox RH, Gardner AM, Winlove CP, Shore AC. Intermittent compression induces transitory hypoxic stimuli, upstream vasodilation and enhanced perfusion of skin capillaries, independent of age and diabetes. J Appl Physiol (1985) 2021; 130:1072-1084. [PMID: 33571053 DOI: 10.1152/japplphysiol.00657.2020] [Citation(s) in RCA: 3] [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
The benefit of enhanced shear stress to the vascular endothelium has been well-documented in conduit arteries but is less understood in skin microcirculation. The aim of this study was to provide physiological evidence of the vascular changes in skin microcirculation induced by intermittent pneumatic compression (IPC) of 1 s cuff inflation (130 mmHg) every 20 s to the palm of the hand for 30 min. The oxygenation and hemodynamics of dorsal mid-phalangeal finger skin microcirculation were assessed by laser Doppler fluximetry and reflectance spectroscopy before, during, and after IPC in 15 young (18-39 years old) and 39 older (40-80 years old) controls and 32 older subjects with type 2 diabetes mellitus. Each individual cuff inflation induced: 1) brief surge in flux immediately after cuff deflation followed by 2) transitory reduction in blood oxygen for ∼4 s, and 3) a second increase in perfusion and oxygenation of the microcirculation peaking ∼11 s after cuff deflation in all subject groups. With no significant change in blood volume observed by reflectance spectroscopy, despite the increased shear stress at the observed site, this second peak in flux and blood oxygen suggests a delayed vasoactive response upstream inducing increased arterial influx in the microcirculation that was higher in older controls and subjects with diabetes compared to young controls (P < 0.001, P < 0.001, respectively) and achieving maximum capillary recruitment in all subject groups. Transitory hypoxic stimuli with conducted vasodilation may be a mechanism through which IPC enhances capillary perfusion in skin microcirculation independent of age and type 2 diabetes mellitus.NEW & NOTEWORTHY This study demonstrates that hand intermittent pneumatic compression evokes transitory hypoxic stimuli in distal finger skin microcirculation inducing vasodilation of arterial inflow vessels, enhanced perfusion, and maximum capillary recruitment in young and older subjects and older subjects with type 2 diabetes mellitus. Enhanced shear stress in the microcirculation did not appear to induce local skin vasodilation.
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Affiliation(s)
- Clare E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Aminat O Adio
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Roger H Fox
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - A Michael Gardner
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - C Peter Winlove
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Angela C Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
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Role of Pericytes in the Initiation and Propagation of Spontaneous Activity in the Microvasculature. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1124:329-356. [PMID: 31183834 DOI: 10.1007/978-981-13-5895-1_14] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The microvasculature is composed of arterioles, capillaries and venules. Spontaneous arteriolar constrictions reduce effective vascular resistance to enhance tissue perfusion, while spontaneous venular constrictions facilitate the drainage of tissue metabolites by pumping blood. In the venules of visceral organs, mural cells, i.e. smooth muscle cells (SMCs) or pericytes, periodically generate spontaneous phasic constrictions, Ca2+ transients and transient depolarisations. These events arise from spontaneous Ca2+ release from the sarco-endoplasmic reticulum (SR/ER) and the subsequent opening of Ca2+-activated chloride channels (CaCCs). CaCC-dependent depolarisation further activates L-type voltage-dependent Ca2+ channels (LVDCCs) that play a critical role in maintaining the synchrony amongst mural cells. Mural cells in arterioles or capillaries are also capable of developing spontaneous activity. Non-contractile capillary pericytes generate spontaneous Ca2+ transients primarily relying on SR/ER Ca2+ release. Synchrony amongst capillary pericytes depends on gap junction-mediated spread of depolarisations resulting from the opening of either CaCCs or T-type VDCCs (TVDCCs) in a microvascular bed-dependent manner. The propagation of capillary Ca2+ transients into arterioles requires the opening of either L- or TVDCCs again depending on the microvascular bed. Since the blockade of gap junctions or CaCCs prevents spontaneous Ca2+ transients in arterioles and venules but not capillaries, capillary pericytes appear to play a primary role in generating spontaneous activity of the microvasculature unit. Pericytes in capillaries where the interchange of substances between tissues and the circulation takes place may provide the fundamental drive for upstream arterioles and downstream venules so that the microvasculature network functions as an integrated unit.
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Yokobori AT, Watanabe K, Saiki Y, Nishikawa Y, Kudo K, Ohmi T, Hayatsu Y, Suzuki M, Sasaki K. Frequency and chaotic analysis of pulsatile motion of blood vessel wall related to aneurysm. Biomed Mater Eng 2019; 30:243-253. [PMID: 30741671 DOI: 10.3233/bme-191048] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
BACKGROUND/OBJECTIVE In this research, using our proposed method, clinical measurements on the pulsatile velocity of blood vessel wall were conducted for cases with aneurysm. Furthermore, detailed analyses of frequency and attracter of trajectories of velocity of blood vessel wall were conducted. On the basis of these analyses, we tried to conduct unified clarification of the change and disturbance of frequency and wave form of pulsatile velocity of blood vessel wall caused by blood vessel diseases such as aneurysm. RESULTS In the pulsation motion of blood vessel wall, vasomotion, which is a regular long periodic fluctuation of amplitude of the pulsatile velocity of blood vessel wall, was found to exist. Furthermore, the shift of its frequency into low frequency region was found to correspond well with an increase in I∗, an indicator of progressive degree of visco elasticity of blood vessel wall and it reflects the mechanical deterioration of blood vessel wall. This long periodic fluctuation of amplitude of the pulsatile velocity of blood vessel wall exists in the low frequency region that composes the frequency of the pulsatile velocity of blood vessel wall. On the other hand, wave forms in high frequency region that compose the frequency of pulsatile velocity of blood vessel wall were found to correspond well with each pulsatile velocity wave form of blood vessel wall itself and their disturbances caused by the existence of aneurysm was typically reflected in these wave forms. CONCLUSION By dividing frequencies that compose the frequency of the pulsatile velocity of blood vessel wall into low and high frequency regions and conducting analyses at each region, the possibility of accurate selective detection of blood vessel diseases such as mechanical deterioration of blood vessel wall (low frequency region) and morphological change of blood vessel wall that is aneurysm (high frequency region) was indicated.
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Affiliation(s)
- A Toshimitsu Yokobori
- Laboratory of Strength of Materials and Science, Strategic Innovation and Research Center, Teikyo University, Tokyo, Japan
| | - Koyu Watanabe
- Division of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Yoshikatsu Saiki
- Division of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Yu Nishikawa
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Kazuki Kudo
- Graduate School of Engineering, Tohoku University, Sendai, Japan
| | - Toshihito Ohmi
- Department of Mechanical Engineering, Shonan Institute of Technology, Fujisawa, Japan
| | - Yukihiro Hayatsu
- Division of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Marina Suzuki
- Division of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
| | - Konosuke Sasaki
- Division of Cardiovascular Surgery, Graduate School of Medicine, Tohoku University, Sendai, Japan
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Abstract
Veins exhibit spontaneous contractile activity, a phenomenon generally termed vasomotion. This is mediated by spontaneous rhythmical contractions of mural cells (i.e. smooth muscle cells (SMCs) or pericytes) in the wall of the vessel. Vasomotion occurs through interconnected oscillators within and between mural cells, entraining their cycles. Pharmacological studies indicate that a key oscillator underlying vasomotion is the rhythmical calcium ion (Ca2+) release-refill cycle of Ca2+ stores. This occurs through opening of inositol 1,4,5-trisphosphate receptor (IP3R)- and/or ryanodine receptor (RyR)-operated Ca2+ release channels in the sarcoplasmic/endoplasmic (SR/ER) reticulum and refilling by the SR/ER reticulum Ca2+ATPase (SERCA). Released Ca2+ from stores near the plasma membrane diffuse through the cytosol to open Ca2+-activated chloride (Cl-) channels, this generating inward current through an efflux of Cl-. The resultant depolarisation leads to the opening of voltage-dependent Ca2+ channels and possibly increased production of IP3, which through Ca2+-induced Ca2+ release (CICR) of IP3Rs and/or RyRs and IP3R-mediated Ca2+ release provide a means by which store oscillators entrain their activity. Intercellular entrainment normally involves current flow through gap junctions that interconnect mural cells and in many cases this is aided by additional connectivity through the endothelium. Once entrainment has occurred the substantial Ca2+ entry that results from the near-synchronous depolarisations leads to rhythmical contractions of the mural cells, this often leading to vessel constriction. The basis for venous/venular vasomotion has yet to be fully delineated but could improve both venous drainage and capillary/venular absorption of blood plasma-associated fluids.
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Cao J, Wang X, Liu H, Alexandrakis G. Directional changes in information flow between human brain cortical regions after application of anodal transcranial direct current stimulation (tDCS) over Broca's area. BIOMEDICAL OPTICS EXPRESS 2018; 9:5296-5317. [PMID: 30460129 PMCID: PMC6238934 DOI: 10.1364/boe.9.005296] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Revised: 09/14/2018] [Accepted: 10/02/2018] [Indexed: 05/05/2023]
Abstract
Little work has been done on the information flow in functional brain imaging and none so far in fNIRS. In this work, alterations in the directionality of net information flow induced by a short-duration, low-current (2 min 40 s; 0.5 mA) and a longer-duration, high-current (8 min; 1 mA) anodal tDCS applied over the Broca's area of the dominant language hemisphere were studied by fNIRS. The tDCS-induced patterns of information flow, quantified by a novel directed phase transfer entropy (dPTE) analysis, were distinct for different hemodynamic frequency bands and were qualitatively similar between low and high-current tDCS. In the endothelial band (0.003-0.02 Hz), the stimulated Broca's area became the strongest hub of outgoing information flow, whereas in the neurogenic band (0.02-0.04 Hz) the contralateral homologous area became the strongest information outflow source. In the myogenic band (0.04-0.15 Hz), only global patterns were seen, independent of tDCS stimulation that were interpreted as Mayer waves. These findings showcase dPTE analysis in fNIRS as a novel, complementary tool for studying cortical activity reorganization after an intervention.
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Hashitani H, Mitsui R, Miwa-Nishimura K, Lam M. Role of capillary pericytes in the integration of spontaneous Ca 2+ transients in the suburothelial microvasculature in situ of the mouse bladder. J Physiol 2018; 596:3531-3552. [PMID: 29873405 DOI: 10.1113/jp275845] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2018] [Accepted: 05/21/2018] [Indexed: 12/19/2022] Open
Abstract
KEY POINTS In the bladder suburothelial microvasculature, pericytes in different microvascular segments develop spontaneous Ca2+ transients with or without associated constrictions. Spontaneous Ca2+ transients in pericytes of all microvascular segments primarily rely on the cycles of Ca2+ uptake and release by the sarco- and endoplasmic reticulum. The synchrony of spontaneous Ca2+ transients in capillary pericytes exclusively relies on the spread of depolarizations resulting from the opening of Ca2+ -activated chloride channels (CaCCs) via gap junctions. CaCC-dependent depolarizations further activate L-type voltage-dependent Ca2+ channels as required for the synchrony of Ca2+ transients in pericytes of pre-capillary arterioles, post-capillary venules and venules. Capillary pericytes may drive spontaneous Ca2+ transients in pericytes within the suburothelial microvascular network by sending CaCC-dependent depolarizations via gap junctions. ABSTRACT Mural cells in the microvasculature of visceral organs develop spontaneous Ca2+ transients. However, the mechanisms underlying the integration of these Ca2+ transients within a microvascular unit remain to be clarified. In the present study, the origin of spontaneous Ca2+ transients and their propagation in the bladder suburothelial microvasculature were explored. Cal-520 fluorescence Ca2+ imaging and immunohistochemistry were carried out on mural cells using mice expressing red fluorescent protein (DsRed) under control of the NG2 promotor. NG2(+) pericytes in both pre-capillary arterioles (PCAs) and capillaries developed synchronous spontaneous Ca2+ transients. By contrast, although NG2-DsRed also labelled arteriolar smooth muscle cells, these cells remained quiescent. Both NG2(+) pericytes in post-capillary venules (PCVs) and NG2(-) venular pericytes exhibited propagated Ca2+ transients. L-type voltage-dependent Ca2+ channel (LVDCC) blockade with nifedipine prevented Ca2+ transients or disrupted their synchrony in PCA, PCV and venular pericytes without dis-synchronizing Ca2+ transients in capillary pericytes. Blockade of gap junctions with carbenoxolone or Ca2+ -activated chloride channels (CaCCs) with 4,4'-diisothiocyanato-2,2'-stilbenedisulphonic acid disodium salt prevented Ca2+ transients in PCA and venular pericytes and disrupted the synchrony of Ca2+ transients in capillary and PCV pericytes. Spontaneous Ca2+ transients in pericytes of all microvascular segments were abolished or suppressed by cyclopiazonic acid, caffeine or tetracaine. The synchrony of Ca2+ transients in capillary pericytes arising from spontaneous Ca2+ release from the sarco- and endoplasmic reticulum appears to rely exclusively on CaCC activation, whereas subsequent LVDCC activation is required for the synchrony of Ca2+ transients in pericytes of other microvascular segments. Capillary pericytes may drive spontaneous activity in the suburothelial microvascular unit to facilitate capillary perfusion.
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Affiliation(s)
- Hikaru Hashitani
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Retsu Mitsui
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Kyoko Miwa-Nishimura
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
| | - Michelle Lam
- Department of Cell Physiology, Graduate School of Medical Sciences, Nagoya City University, Nagoya, Japan
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Bosch BM, Bringard A, Ferretti G, Schwartz S, Iglói K. Effect of cerebral vasomotion during physical exercise on associative memory, a near-infrared spectroscopy study. NEUROPHOTONICS 2017; 4:041404. [PMID: 28785600 PMCID: PMC5526475 DOI: 10.1117/1.nph.4.4.041404] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2017] [Accepted: 07/05/2017] [Indexed: 05/06/2023]
Abstract
Regular physical exercise has been shown to benefit neurocognitive functions, especially enhancing neurogenesis in the hippocampus. However, the effects of a single exercise session on cognitive functions are controversial. To address this issue, we measured hemodynamic changes in the brain during physical exercise using near-infrared spectroscopy (NIRS) and investigated related effects on memory consolidation processes. Healthy young participants underwent two experimental visits. During each visit, they performed an associative memory task in which they first encoded a series of pictures, then spent 30-min exercising or resting, and finally were asked to recall the picture associations. We used NIRS to track changes in oxygenated hemoglobin concentration over the prefrontal cortex during exercise and rest. To characterize local tissue oxygenation and perfusion, we focused on low frequency oscillations in NIRS, also called vasomotion. We report a significant increase in associative memory consolidation after exercise, as compared to after rest, along with an overall increase in vasomotion. Additionally, performance improvement after exercise correlated positively with power in the neurogenic component (0.02 to 0.04 Hz) and negatively with power in the endothelial component (0.003 to 0.02 Hz). Overall, these results suggest that changes in vasomotion over the prefrontal cortex during exercise may promote memory consolidation processes.
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Affiliation(s)
- Blanca Marin Bosch
- University of Geneva, Faculty of Medicine, Department of Neuroscience, Geneva, Switzerland
| | - Aurélien Bringard
- University of Geneva, Faculty of Medicine, Department of Neuroscience, Geneva, Switzerland
- Geneva University Hospitals, Department of Anesthesiology, Pharmacology, and Intensive Care, Geneva, Switzerland
| | - Guido Ferretti
- University of Geneva, Faculty of Medicine, Department of Neuroscience, Geneva, Switzerland
- Geneva University Hospitals, Department of Anesthesiology, Pharmacology, and Intensive Care, Geneva, Switzerland
| | - Sophie Schwartz
- University of Geneva, Faculty of Medicine, Department of Neuroscience, Geneva, Switzerland
- University of Geneva, Swiss Center for Affective Neurosciences, Geneva, Switzerland
- University of Geneva, Geneva Neuroscience Center, Geneva, Switzerland
| | - Kinga Iglói
- University of Geneva, Faculty of Medicine, Department of Neuroscience, Geneva, Switzerland
- University of Geneva, Swiss Center for Affective Neurosciences, Geneva, Switzerland
- University of Geneva, Geneva Neuroscience Center, Geneva, Switzerland
- Address all correspondence to: Kinga Igloi, E-mail:
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Di Marco LY, Farkas E, Martin C, Venneri A, Frangi AF. Is Vasomotion in Cerebral Arteries Impaired in Alzheimer's Disease? J Alzheimers Dis 2016; 46:35-53. [PMID: 25720414 PMCID: PMC4878307 DOI: 10.3233/jad-142976] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
A substantial body of evidence supports the hypothesis of a vascular component in the pathogenesis of Alzheimer’s disease (AD). Cerebral hypoperfusion and blood-brain barrier dysfunction have been indicated as key elements of this pathway. Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder, frequent in AD, characterized by the accumulation of amyloid-β (Aβ) peptide in cerebral blood vessel walls. CAA is associated with loss of vascular integrity, resulting in impaired regulation of cerebral circulation, and increased susceptibility to cerebral ischemia, microhemorrhages, and white matter damage. Vasomotion— the spontaneous rhythmic modulation of arterial diameter, typically observed in arteries/arterioles in various vascular beds including the brain— is thought to participate in tissue perfusion and oxygen delivery regulation. Vasomotion is impaired in adverse conditions such as hypoperfusion and hypoxia. The perivascular and glymphatic pathways of Aβ clearance are thought to be driven by the systolic pulse. Vasomotion produces diameter changes of comparable amplitude, however at lower rates, and could contribute to these mechanisms of Aβ clearance. In spite of potential clinical interest, studies addressing cerebral vasomotion in the context of AD/CAA are limited. This study reviews the current literature on vasomotion, and hypothesizes potential paths implicating impaired cerebral vasomotion in AD/CAA. Aβ and oxidative stress cause vascular tone dysregulation through direct effects on vascular cells, and indirect effects mediated by impaired neurovascular coupling. Vascular tone dysregulation is further aggravated by cholinergic deficit and results in depressed cerebrovascular reactivity and (possibly) impaired vasomotion, aggravating regional hypoperfusion and promoting further Aβ and oxidative stress accumulation.
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Affiliation(s)
- Luigi Yuri Di Marco
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
| | - Eszter Farkas
- Department of Medical Physics and Informatics, Faculty of Medicine and Faculty of Science and Informatics, University of Szeged, Szeged, Hungary
| | - Chris Martin
- Department of Psychology, University of Sheffield, Sheffield, UK
| | - Annalena Venneri
- Department of Neuroscience, University of Sheffield, Sheffield, UK.,IRCCS, Fondazione Ospedale S. Camillo, Venice, Italy
| | - Alejandro F Frangi
- Centre for Computational Imaging and Simulation Technologies in Biomedicine (CISTIB), Department of Electronic and Electrical Engineering, University of Sheffield, Sheffield, UK
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Ho IL, Moshkforoush A, Hong K, Meininger GA, Hill MA, Tsoukias NM, Kuo W. Inherent rhythm of smooth muscle cells in rat mesenteric arterioles: An eigensystem formulation. Phys Rev E 2016; 93:042415. [PMID: 27176337 DOI: 10.1103/physreve.93.042415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2015] [Indexed: 11/07/2022]
Abstract
On the basis of experimental data and mathematical equations in the literature, we remodel the ionic dynamics of smooth muscle cells (SMCs) as an eigensystem formulation, which is valid for investigating finite variations of variables from the equilibrium such as in common experimental operations. This algorithm provides an alternate viewpoint from frequency-domain analysis and enables one to probe functionalities of SMCs' rhythm by means of a resonance-related mechanism. Numerical results show three types of calcium oscillations of SMCs in mesenteric arterioles: spontaneous calcium oscillation, agonist-dependent calcium oscillation, and agonist-dependent calcium spike. For simple single and double SMCs, we demonstrate properties of synchronization among complex signals related to calcium oscillations, and show different correlation relations between calcium and voltage signals for various synchronization and resonance conditions. For practical cell clusters, our analyses indicate that the rhythm of SMCs could (1) benefit enhancements of signal communications among remote cells, (2) respond to a significant calcium peaking against transient stimulations for triggering globally oscillating modes, and (3) characterize the globally oscillating modes via frog-leap (non-molecular-diffusion) calcium waves across inhomogeneous SMCs.
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Affiliation(s)
- I Lin Ho
- Department of Physics, National Chung Hsing University, Taichung 402, Taiwan, Republic of China.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211, USA
| | - Arash Moshkforoush
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2674, Miami, Florida 33174, USA
| | - Kwangseok Hong
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211, USA.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65211, USA
| | - Gerald A Meininger
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211, USA.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65211, USA
| | - Michael A Hill
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri 65211, USA.,Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri 65211, USA
| | - Nikolaos M Tsoukias
- Department of Biomedical Engineering, Florida International University, 10555 West Flagler Street, EC 2674, Miami, Florida 33174, USA
| | - Watson Kuo
- Department of Physics, National Chung Hsing University, Taichung 402, Taiwan, Republic of China
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Thorn CE, Shore AC. The role of perfusion in the oxygen extraction capability of skin and skeletal muscle. Am J Physiol Heart Circ Physiol 2016; 310:H1277-84. [PMID: 27016577 DOI: 10.1152/ajpheart.00047.2016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2016] [Accepted: 03/22/2016] [Indexed: 12/19/2022]
Abstract
Oxygen extraction (OE) by all cells is dependent on an adequate supply of oxygen in proximal blood vessels and the cell's need and ability to uptake that oxygen. Here the role of blood flow in regulating OE in skin and skeletal muscle was investigated in lean and obese men. OE was derived by two optical reflectance spectroscopy techniques: 1) from the rate of fall in mean blood saturation during a 4 min below knee arterial occlusion, and thus no blood flow, in calf skin and skeletal muscle and 2) in perfused, unperturbed skin, using the spontaneous falls in mean blood saturation induced by vasomotion in calf and forearm skin of 24 subjects, 12 lean and 12 obese. OE in perfused skin was significantly higher in lean compared with obese subjects in forearm (Mann-Whitney, P < 0.004) and calf (P < 0.001) and did not correlate with OE in unperfused skin (ρ = -0.01, P = 0.48). With arterial occlusion and thus no blood flow, skin OE in lean and obese subjects no longer differed (P = 0.23, not significant). In contrast in skeletal muscle with arterial occlusion and no blood flow, the difference in OE between lean and obese subjects occurred, with obese subjects exhibiting significantly higher OE (P < 0.012). The classic model of metabolic blood flow regulation to support oxygen extraction is evident in perfused skin; OE is perturbed without blood flow and reduced in obesity. In resting skeletal muscle other mechanism(s), independent of blood flow, are implicated in oxygen extraction.
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Affiliation(s)
- Clare E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and National Institute of Health Research Exeter Clinical Research Facility, Exeter, United Kingdom
| | - Angela C Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School and National Institute of Health Research Exeter Clinical Research Facility, Exeter, United Kingdom
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15
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Del Pozzi AT, Miller JT, Hodges GJ. The effect of heating rate on the cutaneous vasomotion responses of forearm and leg skin in humans. Microvasc Res 2016; 105:77-84. [PMID: 26808211 DOI: 10.1016/j.mvr.2016.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 01/19/2016] [Accepted: 01/20/2016] [Indexed: 11/19/2022]
Abstract
We examined skin blood flow (SkBF) and vasomotion in the forearm and leg using laser-Doppler fluxmetry (LDF) and spectral analysis to investigate endothelial, sympathetic, and myogenic activities in response to slow (0.1 °C·10 s(-1)) and fast (0.5 °C·10 s(-1)) local heating. At 33 °C (thermoneutral) endothelial activity was higher in the legs than the forearms (P ≤ 0.02). Fast-heating increased SkBF more than slow heating (P=0.037 forearm; P=0.002 leg). At onset of 42 °C, endothelial (P=0.043 forearm; P=0.48 leg) activity increased in both regions during the fast-heating protocol. Following prolonged heating (42 °C) endothelial activity was higher in both the forearm (P=0.002) and leg (P<0.001) following fast-heating. These results confirm regional differences in the response to local heating and suggest that the greater increase in SkBF in response to fast local heating is initially due to increased endothelial and sympathetic activity. Furthermore, with sustained local skin heating, greater vasodilatation was observed with fast heating compared to slow heating. These data indicate that this difference is due to greater endothelial activity following fast heating compared to slow heating, suggesting that the rate of skin heating may alter the mechanisms contributing to cutaneous vasodilatation.
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Affiliation(s)
- Andrew T Del Pozzi
- Integrative Exercise Physiology Laboratory, School of Kinesiology, Ball State University, Muncie, IN 47306, United States
| | - James T Miller
- Exercise Physiology Laboratory, Department of Kinesiology, The University of Alabama, Tuscaloosa, AL 35487, United States
| | - Gary J Hodges
- Environmental Ergonomics Laboratory, Department of Kinesiology, Brock University, St. Catharines, ON L2S 3A1, Canada.
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16
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Dormanns K, van Disseldorp EMJ, Brown RG, David T. Neurovascular coupling and the influence of luminal agonists via the endothelium. J Theor Biol 2014; 364:49-70. [PMID: 25167790 DOI: 10.1016/j.jtbi.2014.08.029] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Revised: 08/15/2014] [Accepted: 08/18/2014] [Indexed: 11/18/2022]
Abstract
A numerical model of neurovascular coupling (NVC) is presented based on neuronal activity coupled to vasodilation/contraction models via the astrocytic mediated perivascular K(+) and the smooth muscle cell Ca(2+) pathway. Luminal agonists acting on P2Y receptors on the endothelial cell surface provide a flux of IP3 into the endothelial cytosol. This concentration of IP3 is transported via gap junctions between endothelial and smooth muscle cells providing a source of sacroplasmic derived Ca(2+) in the smooth muscle cell. The model is able to relate a neuronal input signal to the corresponding vessel reaction. Results indicate that blood flow mediated IP3 production via the agonist ATP has a substantial effect on the contraction/dilation dynamics of the SMC. The resulting variation in cytosolic Ca(2+) can enhance and inhibit the flow of blood to the cortical tissue. IP3 coupling between endothelial and smooth muscle cells seems to be important in the dynamics of the smooth muscle cell. The VOCC channels are, due to the hyperpolarisation from K(+) SMC efflux, almost entirely closed and do not seem to play a significant role during neuronal activity. The current model shows that astrocytic Ca(2+) is not necessary for neurovascular coupling to occur in contrast to a number of experiments outlining the importance of astrocytic Ca(2+) in NVC, however this Ca(2+) pathway is not the only one mediating NVC. Importantly agonists in flowing blood have a significant influence on the endothelial and smooth muscle cell dynamics.
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Affiliation(s)
- K Dormanns
- Bluefern Supercomputing Unit, University of Canterbury, Christchurch, New Zealand
| | - E M J van Disseldorp
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - R G Brown
- Institute of Fundamental Sciences, Massey University, Palmerston North, New Zealand
| | - T David
- Bluefern Supercomputing Unit, University of Canterbury, Christchurch, New Zealand.
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17
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Li L, Wang R, Ma KT, Li XZ, Zhang CL, Liu WD, Zhao L, Si JQ. Differential effect of calcium-activated potassium and chloride channels on rat basilar artery vasomotion. ACTA ACUST UNITED AC 2014; 34:482-490. [PMID: 25135715 DOI: 10.1007/s11596-014-1303-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2014] [Revised: 07/08/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Li Li
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, 832002, China
| | - Rui Wang
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
| | - Ke-Tao Ma
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, 832002, China
| | - Xin-Zhi Li
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, 832002, China
- Department of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China
| | - Chuan-Lin Zhang
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
| | - Wei-Dong Liu
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
| | - Lei Zhao
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, 832002, China
| | - Jun-Qiang Si
- Department of Physiology, Medical College of Shihezi University, Shihezi, 832002, China.
- The Key Laboratory of Xinjiang Endemic and Ethnic Diseases, Medical College of Shihezi University, Shihezi, 832002, China.
- Department of Neurobiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, 430030, China.
- Department of Physiology, Wuhan University School of Basic Medical Sciences, Wuhan, 430070, China.
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18
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de Boer MP, Meijer RI, Newman J, Stehouwer CD, Eringa EC, Smulders YM, Serné EH. Insulin-Induced Changes in Microvascular Vasomotion and Capillary Recruitment are Associated in Humans. Microcirculation 2014; 21:380-7. [DOI: 10.1111/micc.12114] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 01/13/2014] [Indexed: 11/30/2022]
Affiliation(s)
- Michiel P. de Boer
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Rick I. Meijer
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - John Newman
- Menzies Research Institute; University of Tasmania; Hobart Tasmania Australia
| | - Coen D.A. Stehouwer
- Department of Internal Medicine and the Cardiovascular Research Institute Maastricht (CARIM); University Hospital Maastricht; Maastricht The Netherlands
| | - Etto C. Eringa
- Laboratory for Physiology; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Yvo M. Smulders
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
| | - Erik H. Serné
- Department of Internal Medicine; Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center; Amsterdam The Netherlands
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19
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Impact of long-term exposure to cigarette smoking on skin microvascular function. Microvasc Res 2014; 93:46-51. [DOI: 10.1016/j.mvr.2014.03.001] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Revised: 02/11/2014] [Accepted: 03/03/2014] [Indexed: 11/17/2022]
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20
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Rayshubskiy A, Wojtasiewicz TJ, Mikell CB, Bouchard MB, Timerman D, Youngerman BE, McGovern RA, Otten ML, Canoll P, McKhann GM, Hillman EMC. Direct, intraoperative observation of ~0.1 Hz hemodynamic oscillations in awake human cortex: implications for fMRI. Neuroimage 2014; 87:323-31. [PMID: 24185013 PMCID: PMC3961585 DOI: 10.1016/j.neuroimage.2013.10.044] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Revised: 09/22/2013] [Accepted: 10/21/2013] [Indexed: 10/26/2022] Open
Abstract
An almost sinusoidal, large amplitude ~0.1 Hz oscillation in cortical hemodynamics has been repeatedly observed in species ranging from mice to humans. However, the occurrence of 'slow sinusoidal hemodynamic oscillations' (SSHOs) in human functional magnetic resonance imaging (fMRI) studies is rarely noted or considered. As a result, little investigation into the cause of SSHOs has been undertaken, and their potential to confound fMRI analysis, as well as their possible value as a functional biomarker has been largely overlooked. Here, we report direct observation of large-amplitude, sinusoidal ~0.1 Hz hemodynamic oscillations in the cortex of an awake human undergoing surgical resection of a brain tumor. Intraoperative multispectral optical intrinsic signal imaging (MS-OISI) revealed that SSHOs were spatially localized to distinct regions of the cortex, exhibited wave-like propagation, and involved oscillations in the diameter of specific pial arterioles, indicating that the effect was not the result of systemic blood pressure oscillations. fMRI data collected from the same subject 4 days prior to surgery demonstrates that ~0.1 Hz oscillations in the BOLD signal can be detected around the same region. Intraoperative optical imaging data from a patient undergoing epilepsy surgery, in whom sinusoidal oscillations were not observed, is shown for comparison. This direct observation of the '0.1 Hz wave' in the awake human brain, using both intraoperative imaging and pre-operative fMRI, confirms that SSHOs occur in the human brain, and can be detected by fMRI. We discuss the possible physiological basis of this oscillation and its potential link to brain pathologies, highlighting its relevance to resting-state fMRI and its potential as a novel target for functional diagnosis and delineation of neurological disease.
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Affiliation(s)
- Aleksandr Rayshubskiy
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering, Columbia University, USA
| | | | | | - Matthew B Bouchard
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering, Columbia University, USA
| | - Dmitriy Timerman
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering, Columbia University, USA
| | | | | | - Marc L Otten
- Department of Neurosurgery, Columbia University, USA
| | - Peter Canoll
- Department of Pathology and Cell Biology, Columbia University, USA
| | - Guy M McKhann
- Department of Neurosurgery, Columbia University, USA
| | - Elizabeth M C Hillman
- Laboratory for Functional Optical Imaging, Department of Biomedical Engineering, Columbia University, USA; Department of Radiology, Columbia University, USA.
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Wu SC, Crews RT, Najafi B, Slone-Rivera N, Minder JL, Andersen CA. Safety and efficacy of mild compression (18-25 mm Hg) therapy in patients with diabetes and lower extremity edema. J Diabetes Sci Technol 2012; 6:641-7. [PMID: 22768895 PMCID: PMC3440039 DOI: 10.1177/193229681200600319] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
BACKGROUND Patients with diabetes often present with lower extremity (LE) edema; however, because of concomitant peripheral arterial disease, compression therapy is generally avoided by providers in fear of compromising arterial circulation. This pilot study sought to assess whether diabetic socks with mild compression (18-25 mm Hg) can reduce LE edema in patients with diabetes without negatively impacting vascularity. METHODS Eighteen subjects (9 males, 9 females) aged 61 ± 11 years with diabetes, LE edema, and a mean ankle-brachial index (ABI) of 1.10 ± 0.21 successfully completed this uncontrolled study. At baseline, subjects were fitted and instructed to wear the socks during all waking hours. Follow-up visits occurred weekly for four consecutive weeks. Edema was quantified through midfoot, ankle, and calf circumferences and cutaneous fluid measurements. Vascular status was tracked via ABI. RESULTS Repeated measures analysis of variance and least significant difference post hoc analyses were used for data analyses. Calf circumferences showed a statistically significant (p < .05) decrease of 1.3 ± 0.28 cm after just one week and remained significantly smaller than baseline throughout the study. Foot circumferences were significantly reduced at week 2 (-0.98 ± 0.35 cm) and remained significantly below baseline for the remainder of the study. The ankle also demonstrated a trend of circumference reduction but was not statistically significant. Cutaneous edema significantly reduced by week 3 (-3.1 ± 1.3 U) and remained so at week 4. Ankle-brachial index significantly increased (0.14 ± 0.049) at week 2 but was not significantly higher at weeks 3 or 4. No adverse events occurred during the study. CONCLUSIONS Mild compression therapy (18-25 mm Hg) decreased swelling in diabetes patients with LE edema without compromising vascularity.
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Affiliation(s)
- Stephanie C Wu
- Center for Lower Extremity Ambulatory Research, Dr. William M. Scholl College of Podiatric Medicine at Rosalind Franklin University of Medicine and Science, North Chicago, Illinois 60064, USA.
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Kapela A, Nagaraja S, Parikh J, Tsoukias NM. Modeling Ca2+ signaling in the microcirculation: intercellular communication and vasoreactivity. Crit Rev Biomed Eng 2012; 39:435-60. [PMID: 22196162 DOI: 10.1615/critrevbiomedeng.v39.i5.50] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
A network of intracellular signaling pathways and complex intercellular interactions regulate calcium mobilization in vascular cells, arteriolar tone, and blood flow. Different endothelium-derived vasoreactive factors have been identified and the importance of myoendothelial communication in vasoreactivity is now well appreciated. The ability of many vascular networks to conduct signals upstream also is established. This phenomenon is critical for both short-term changes in blood perfusion as well as long-term adaptations of a vascular network. In addition, in a phenomenon termed vasomotion, arterioles often exhibit spontaneous oscillations in diameter. This is thought to improve tissue oxygenation and enhance blood flow. Experimentation has begun to reveal important aspects of the regulatory machinery and the significance of these phenomena for the regulation of local perfusion and oxygenation. Mathematical modeling can assist in elucidating the complex signaling mechanisms that participate in these phenomena. This review highlights some of the important experimental studies and relevant mathematical models that provide the current understanding of these mechanisms in vasoreactivity.
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Affiliation(s)
- Adam Kapela
- Department of Biomedical Engineering, Florida International University, Miami, FL, USA
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Increased finger skin vasoreactivity and stimulated vasomotion associated with simvastatin therapy in systemic sclerosis hypercholesterolemic patients. Rheumatol Int 2011; 32:3715-21. [DOI: 10.1007/s00296-011-2183-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2011] [Accepted: 10/18/2011] [Indexed: 10/15/2022]
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24
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Investigation of skin vasoreactivity and blood flow oscillations in hypertensive patients. J Hypertens 2011; 29:1569-76. [DOI: 10.1097/hjh.0b013e328348b653] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Thorn CE, Kyte H, Slaff DW, Shore AC. An association between vasomotion and oxygen extraction. Am J Physiol Heart Circ Physiol 2011; 301:H442-9. [PMID: 21602466 PMCID: PMC3154677 DOI: 10.1152/ajpheart.01316.2010] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Accepted: 05/12/2011] [Indexed: 02/08/2023]
Abstract
Vasomotion is defined as a spontaneous local oscillation in vascular tone whose function is unclear but may have a beneficial effect on tissue oxygenation. Optical reflectance spectroscopy and laser Doppler fluximetry provide unique insights into the possible mechanisms of vasomotion in the cutaneous microcirculation through the simultaneous measurement of changes in concentration of oxyhemoglobin ([HbO(2)]), deoxyhemoglobin ([Hb]), and mean blood saturation (S(mb)O(2)) along with blood volume and flux. The effect of vasomotion at frequencies <0.02 Hz attributed to endothelial activity was studied in the dorsal forearm skin of 24 healthy males. Fourier analysis identified periodic fluctuations in S(mb)O(2) in 19 out of 24 subjects, predominantly where skin temperatures were >29.3°C (X(2) = 6.19, P < 0.02). A consistent minimum threshold in S(mb)O(2) (mean: 39.4%, range: 24.0-50.6%) was seen to precede a sudden transient surge in flux, inducing a fast rise in S(mb)O(2). The integral increase in flux correlated with the integral increase in [HbO(2)] (Pearson's correlation r(2) = 0.50, P < 0.001) and with little change in blood volume suggests vasodilation upstream, responding to a low S(mb)O(2) downstream. This transient surge in flux was followed by a sustained period where blood volume and flux remained relatively constant and a steady decrease in [HbO(2)] and equal and opposite increase in [Hb] was considered to provide a measure of oxygen extraction. A measure of this oxygen extraction has been approximated by the mean half-life of the decay in S(mb)O(2) during this period. A comparison of the mean half-life in the 8 normal subjects [body mass index (BMI) <26.0 kg/m(2)] of 12.2 s and the 11 obese subjects (BMI >29.5 kg/m(2)) of 18.8 s was statistically significant (Mann Whitney, P < 0.004). The S(mb)O(2) fluctuated spontaneously in this saw tooth manner by an average of 9.0% (range 4.0-16.2%) from mean S(mb)O(2) values ranging from 30 to 52%. These observations support the hypothesis that red blood cells may act as sensors of local tissue hypoxia, through the oxygenation status of the hemoglobin, and initiate improved local perfusion to the tissue through hypoxic vasodilation.
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Affiliation(s)
- Clare E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, Peninsula College of Medicine and Dentistry, University of Exeter, National Institute for Health Research Peninsula Clinical Research Facility, Exeter, United Kingdom.
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26
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Broegger T, Jacobsen JCB, Secher Dam V, Boedtkjer DMB, Kold-Petersen H, Pedersen FS, Aalkjaer C, Matchkov VV. Bestrophin is important for the rhythmic but not the tonic contraction in rat mesenteric small arteries. Cardiovasc Res 2011; 91:685-93. [PMID: 21498420 DOI: 10.1093/cvr/cvr111] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
AIMS We have previously characterized a cGMP-dependent Ca(2+)-activated Cl(-) current in vascular smooth muscle cells (SMCs) and have shown its dependence on bestrophin-3 expression. We hypothesize that this current is important for synchronization of SMCs in the vascular wall. In the present study, we aimed to test this hypothesis by transfecting rat mesenteric small arteries in vivo with siRNA specifically targeting bestrophin-3. METHODS AND RESULTS The arteries were tested 3 days after transfection in vitro for isometric force development and for intracellular Ca(2+) in SMCs. Bestrophin-3 expression was significantly reduced compared with arteries transfected with mutated siRNA. mRNA levels for bestrophin-1 and -2 were also significantly reduced by bestrophin-3 down-regulation. This is suggested to be secondary to specific bestrophin-3 down-regulation since siRNAs targeting different exons of the bestrophin-3 gene had identical effects on bestrophin-1 and -2 expression. The transfection affected neither the maximal contractile response nor the sensitivity to norepinephrine and arginine-vasopressin. The amplitude of agonist-induced vasomotion was significantly reduced in arteries down-regulated for bestrophins compared with controls, and asynchronous Ca(2+) waves appeared in the SMCs. The average frequency of vasomotion was not different. 8Br-cGMP restored vasomotion in arteries where the endothelium was removed, but oscillation amplitude was still significantly less in bestrophin-down-regulated arteries. Thus, vasomotion properties were consistent with those previously characterized for rat mesenteric small arteries. Data from our mathematical model are consistent with the experimental results. CONCLUSION This study demonstrates the importance of bestrophins for synchronization of SMCs and strongly supports our hypothesis for generation of vasomotion.
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Affiliation(s)
- Torbjoern Broegger
- Department of Physiology and Biophysics, Aarhus University, Ole Worms Alle bygn.4, 1163, Aarhus C 8000, Denmark
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Pradhan RK, Chakravarthy VS. Informational dynamics of vasomotion in microvascular networks: a review. Acta Physiol (Oxf) 2011; 201:193-218. [PMID: 20887358 DOI: 10.1111/j.1748-1716.2010.02198.x] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Vasomotion refers to spontaneous oscillation of small vessels observed in many microvascular beds. It is an intrinsic phenomenon unrelated to cardiac rhythm or neural and hormonal regulation. Vasomotion is found to be particularly prominent under conditions of metabolic stress. In spite of a significant existent literature on vasomotion, its physiological and pathophysiological roles are not clear. It is thought that modulation of vasomotion by vasoactive substances released by metabolizing tissue plays a role in ensuring optimal delivery of nutrients to the tissue. Vasomotion rhythms exhibit a great variety of temporal patterns from regular oscillations to chaos. The nature of vasomotion rhythm is believed to be significant to its function, with chaotic vasomotion offering several physiological advantages over regular, periodic vasomotion. In this article, we emphasize that vasomotion is best understood as a network phenomenon. When there is a local metabolic demand in tissue, an ideal vascular response should extend beyond local microvasculature, with coordinated changes over multiple vascular segments. Mechanisms of information transfer over a vessel network have been discussed in the literature. The microvascular system may be regarded as a network of dynamic elements, interacting, either over the vascular anatomical network via gap junctions, or physiologically by exchange of vasoactive substances. Drawing analogies with spatiotemporal patterns in neuronal networks of central nervous system, we ask if properties like synchronization/desynchronization of vasomotors have special significance to microcirculation. Thus the contemporary literature throws up a novel view of microcirculation as a network that exhibits complex, spatiotemporal and informational dynamics.
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Affiliation(s)
- R K Pradhan
- Biotechnology and Bioengineering Center, Medical College of Wisconsin, Milwaukee, WI 53226-6509, USA.
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28
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Rossi M, Nannipieri M, Anselmino M, Pesce M, Muscelli E, Santoro G, Ferrannini E. Skin Vasodilator Function and Vasomotion in Patients with Morbid Obesity: Effects of Gastric Bypass Surgery. Obes Surg 2010; 21:87-94. [DOI: 10.1007/s11695-010-0286-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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de Wit C, Griffith TM. Connexins and gap junctions in the EDHF phenomenon and conducted vasomotor responses. Pflugers Arch 2010; 459:897-914. [PMID: 20379740 DOI: 10.1007/s00424-010-0830-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2010] [Accepted: 03/16/2010] [Indexed: 12/21/2022]
Abstract
It is becoming increasingly evident that electrical signaling via gap junctions plays a central role in the physiological control of vascular tone via two related mechanisms (1) the endothelium-derived hyperpolarizing factor (EDHF) phenomenon, in which radial transmission of hyperpolarization from the endothelium to subjacent smooth muscle promotes relaxation, and (2) responses that propagate longitudinally, in which electrical signaling within the intimal and medial layers of the arteriolar wall orchestrates mechanical behavior over biologically large distances. In the EDHF phenomenon, the transmitted endothelial hyperpolarization is initiated by the activation of Ca(2+)-activated K(+) channels channels by InsP(3)-induced Ca(2+) release from the endoplasmic reticulum and/or store-operated Ca(2+) entry triggered by the depletion of such stores. Pharmacological inhibitors of direct cell-cell coupling may thus attenuate EDHF-type smooth muscle hyperpolarizations and relaxations, confirming the participation of electrotonic signaling via myoendothelial and homocellular smooth muscle gap junctions. In contrast to isolated vessels, surprisingly little experimental evidence argues in favor of myoendothelial coupling acting as the EDHF mechanism in arterioles in vivo. However, it now seems established that the endothelium plays the leading role in the spatial propagation of arteriolar responses and that these involve poorly understood regenerative mechanisms. The present review will focus on the complex interactions between the diverse cellular signaling mechanisms that contribute to these phenomena.
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Affiliation(s)
- Cor de Wit
- Institut für Physiologie, Universität zu Lübeck, Ratzeburger Allee 160, 23538, Lübeck, Germany.
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30
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Abstract
Caveolae are omega-shaped membrane invaginations present in essentially all cell types in the cardiovascular system, and numerous functions have been ascribed to these structures. Caveolae formation depends on caveolins, cholesterol and polymerase I and transcript release factor-Cavin (PTRF-Cavin). The current review summarizes and critically discusses the cardiovascular phenotypes reported in caveolin-1-deficient mice. Major changes in the structure and function of heart, lung and blood vessels have been documented, suggesting that caveolae play a critical role at the interface between blood and surrounding tissue. According to an emerging paradigm, many of these changes are secondary to uncoupling of endothelial nitric oxide synthase. Thus, nitric oxide synthase not only synthesizes more nitric oxide in the absence of caveolin-1, but also more superoxide with potential pathogenic consequences. It is further argued that the vasodilating drive from increased nitric oxide production in caveolin-1-deficient mice is balanced by changes in the vascular media that favour increased dynamic resistance regulation. Harnessing the therapeutic opportunities buried in caveolae, while challenging, could expand the arsenal of treatment options in cancer, lung disease and atherosclerosis.
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Affiliation(s)
- A Rahman
- Division of Vascular and Airway Research, Department of Experimental Medical Science, Lund University, Lund, Sweden
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