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Webb AJ, Klerman EB, Mandeville ET. Circadian and Diurnal Regulation of Cerebral Blood Flow. Circ Res 2024; 134:695-710. [PMID: 38484025 PMCID: PMC10942227 DOI: 10.1161/circresaha.123.323049] [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: 11/25/2023] [Revised: 01/30/2024] [Accepted: 02/07/2024] [Indexed: 03/17/2024]
Abstract
Circadian and diurnal variation in cerebral blood flow directly contributes to the diurnal variation in the risk of stroke, either through factors that trigger stroke or due to impaired compensatory mechanisms. Cerebral blood flow results from the integration of systemic hemodynamics, including heart rate, cardiac output, and blood pressure, with cerebrovascular regulatory mechanisms, including cerebrovascular reactivity, autoregulation, and neurovascular coupling. We review the evidence for the circadian and diurnal variation in each of these mechanisms and their integration, from the detailed evidence for mechanisms underlying the nocturnal nadir and morning surge in blood pressure to identifying limited available evidence for circadian and diurnal variation in cerebrovascular compensatory mechanisms. We, thus, identify key systemic hemodynamic factors related to the diurnal variation in the risk of stroke but particularly identify the need for further research focused on cerebrovascular regulatory mechanisms.
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Affiliation(s)
- Alastair J.S. Webb
- Department of Clinical Neurosciences, Wolfson Centre for Prevention of Stroke and Dementia, University of Oxford, United Kingdom (A.J.S.W.)
| | - Elizabeth B. Klerman
- Department of Clinical Neurosciences, Wolfson Centre for Prevention of Stroke and Dementia, University of Oxford, United Kingdom (A.J.S.W.)
- Department of Neurology, Massachusetts General Hospital, Boston (E.B.K.)
- Division of Sleep and Circadian Disorders, Department of Medicine, Brigham and Women’s Hospital, Boston, MA (E.B.K.)
- Division of Sleep Medicine, Harvard Medical School, Boston, MA (E.B.K.)
| | - Emiri T. Mandeville
- Departments of Radiology and Neurology, Neuroprotection Research Laboratories, Massachusetts General Hospital, Harvard Medical School, Boston (E.T.M.)
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Faraci FM, Scheer FA. Hypertension: Causes and Consequences of Circadian Rhythms in Blood Pressure. Circ Res 2024; 134:810-832. [PMID: 38484034 PMCID: PMC10947115 DOI: 10.1161/circresaha.124.323515] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2024] [Accepted: 02/16/2024] [Indexed: 03/19/2024]
Abstract
Hypertension is extremely common, affecting approximately 1 in every 2 adults globally. Chronic hypertension is the leading modifiable risk factor for cardiovascular disease and premature mortality worldwide. Despite considerable efforts to define mechanisms that underlie hypertension, a potentially major component of the disease, the role of circadian biology has been relatively overlooked in both preclinical models and humans. Although the presence of daily and circadian patterns has been observed from the level of the genome to the whole organism, the functional and structural impact of biological rhythms, including mechanisms such as circadian misalignment, remains relatively poorly defined. Here, we review the impact of daily rhythms and circadian systems in regulating blood pressure and the onset, progression, and consequences of hypertension. There is an emphasis on the impact of circadian biology in relation to vascular disease and end-organ effects that, individually or in combination, contribute to complex phenotypes such as cognitive decline and the loss of cardiac and brain health. Despite effective treatment options for some individuals, control of blood pressure remains inadequate in a substantial portion of the hypertensive population. Greater insight into circadian biology may form a foundation for novel and more widely effective molecular therapies or interventions to help in the prevention, treatment, and management of hypertension and its related pathophysiology.
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Affiliation(s)
- Frank M. Faraci
- Department of Internal Medicine, Francois M. Abboud Cardiovascular Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1081
- Department of Neuroscience and Pharmacology, Francois M. Abboud Cardiovascular Center, Carver College of Medicine, University of Iowa, Iowa City, IA 52242-1081
| | - Frank A.J.L. Scheer
- Division of Sleep Medicine, Harvard Medical School, Brigham and Women's Hospital, Boston, Massachusetts, 02115
- Medical Chronobiology Program, Division of Sleep and Circadian Disorders, Departments of Medicine and Neurology, Brigham and Women's Hospital, Boston, Massachusetts, 02115
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3
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Mitchell JW, Gillette MU. Development of circadian neurovascular function and its implications. Front Neurosci 2023; 17:1196606. [PMID: 37732312 PMCID: PMC10507717 DOI: 10.3389/fnins.2023.1196606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Accepted: 08/14/2023] [Indexed: 09/22/2023] Open
Abstract
The neurovascular system forms the interface between the tissue of the central nervous system (CNS) and circulating blood. It plays a critical role in regulating movement of ions, small molecules, and cellular regulators into and out of brain tissue and in sustaining brain health. The neurovascular unit (NVU), the cells that form the structural and functional link between cells of the brain and the vasculature, maintains the blood-brain interface (BBI), controls cerebral blood flow, and surveils for injury. The neurovascular system is dynamic; it undergoes tight regulation of biochemical and cellular interactions to balance and support brain function. Development of an intrinsic circadian clock enables the NVU to anticipate rhythmic changes in brain activity and body physiology that occur over the day-night cycle. The development of circadian neurovascular function involves multiple cell types. We address the functional aspects of the circadian clock in the components of the NVU and their effects in regulating neurovascular physiology, including BBI permeability, cerebral blood flow, and inflammation. Disrupting the circadian clock impairs a number of physiological processes associated with the NVU, many of which are correlated with an increased risk of dysfunction and disease. Consequently, understanding the cell biology and physiology of the NVU is critical to diminishing consequences of impaired neurovascular function, including cerebral bleeding and neurodegeneration.
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Affiliation(s)
- Jennifer W. Mitchell
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
| | - Martha U. Gillette
- Department of Cell and Developmental Biology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Neuroscience Program, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Beckman Institute for Advanced Science and Technology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Department of Molecular and Integrative Physiology, University of Illinois Urbana-Champaign, Urbana, IL, United States
- Carle-Illinois College of Medicine, University of Illinois Urbana-Champaign, Urbana, IL, United States
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Shariffi B, Lloyd IN, Cessac ME, Harper JL, Limberg JK. Reproducibility and diurnal variation in middle cerebral artery blood velocity in healthy humans. Exp Physiol 2023; 108:692-705. [PMID: 36951536 PMCID: PMC10148902 DOI: 10.1113/ep090873] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Accepted: 03/02/2023] [Indexed: 03/24/2023]
Abstract
NEW FINDINGS What is the central question of this study? We sought to establish between-day reproducibility in estimates of middle cerebral artery blood velocity (MCAv) and cerebrovascular reactivity (CVR) in young, healthy male and female adults in tightly controlled experimental conditions. What is the main finding and its importance? Measures of MCAv assessed during morning, afternoon and evening hours are reproducible between days. There is diurnal variation in CVR, with values being highest during the evening compared with the morning. Greater diurnal variation in CVR is associated with more efficient sleep and greater nocturnal blood pressure dipping. These data enhance our understanding of modulators of MCAv and CVR. ABSTRACT Transcranial Doppler (TCD) is used to assess cerebral blood velocity (CBV) and cerebrovascular reactivity (CVR). Assessments of TCD reproducibility are limited, and few include multiple within-day measurements. We sought to establish reproducibility of CBV and CVR in healthy adults during three time periods (morning, afternoon and evening). We hypothesized that CBV and CVR measured at the same time of day are reproducible between days. We also hypothesized that CBV and CVR exhibit diurnal variation, with measurements being higher in the evening compared with morning/afternoon hours. Twelve adults [six male and six female, 27 years (95% CI, 22-31 years)] completed three measurements (morning, afternoon and evening) on two separate days in controlled conditions (e.g., meals, activity and sleep). Middle cerebral artery blood velocity (MCAv, TCD) was measured continuously at rest and during two CVR tests (end-expiratory apnoea and carbogen inhalation). Intraclass correlation coefficients for resting MCAv showed moderate to good reproducibility, which did not differ between morning, afternoon and evening (0.87, 0.56 and 0.67, respectively; P > 0.05). Intraclass correlation coefficients for peak MCAv during apnoea (0.80, 0.46 and 0.65, respectively; P > 0.05) and minute 2 of carbogen inhalation (0.81, 0.74 and 0.73, respectively; P > 0.05) were also not different from morning compared with afternoon/evening. Time of day had no effect on resting MCAv (F = 0.69, P = 0.51, ƞp 2 = 0.06) or the peak response to apnoea (F = 1.00, P = 0.39, ƞp 2 = 0.08); however, peak MCAv during carbogen breathing exhibited diurnal variation, with highest values in the evening (F = 3.41, P = 0.05, ƞp 2 = 0.24). Measures of CBV and CVR assessed via TCD during morning, afternoon and evening hours are reproducible between days. There is diurnal variation in the MCAv response to carbogen exposure, with CVR being highest during evening compared with morning hours.
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Affiliation(s)
- Brian Shariffi
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Iman N. Lloyd
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Mikala E. Cessac
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Jennifer L. Harper
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
| | - Jacqueline K. Limberg
- Department of Nutrition and Exercise PhysiologyUniversity of MissouriColumbiaMissouriUSA
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Ahmad F, Sachdeva P, Sarkar J, Izhaar R. Circadian dysfunction and Alzheimer's disease - An updated review. Aging Med (Milton) 2023; 6:71-81. [PMID: 36911088 PMCID: PMC10000289 DOI: 10.1002/agm2.12221] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2022] [Revised: 07/15/2022] [Accepted: 08/01/2022] [Indexed: 11/09/2022] Open
Abstract
Alzheimer's disease (AD) is considered to be the most typical form of dementia that provokes irreversible cognitive impairment. Along with cognitive impairment, circadian rhythm dysfunction is a fundamental factor in aggravating AD. A link among circadian rhythms, sleep, and AD has been well-documented. The etiopathogenesis of circadian system disruptions and AD serves some general characteristics that also open up the possibility of viewing them as a mutually reliant path. In this review, we have focused on different factors that are related to circadian rhythm dysfunction. The various pathogenic factors, such as amyloid-beta, neurofibrillary tangles, oxidative stress, neuroinflammation, and circadian rhythm dysfunction may all contribute to AD. In this review, we also tried to focus on melatonin which is produced from the pineal gland and can be used to treat circadian dysfunction in AD. Aside from amyloid beta, tau pathology may have a notable influence on sleep. Conclusively, the center of this review is primarily based on the principal mechanistic complexities associated with circadian rhythm disruption, sleep deprivation, and AD, and it also emphasizes the potential therapeutic strategies to treat and prevent the progression of AD.
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Affiliation(s)
- Faizan Ahmad
- Department of Medical Elementology and Toxicology Jamia Hamdard University Delhi India
| | - Punya Sachdeva
- Amity Institute of Neuropsychology and Neurosciences Amity University Noida Uttar Pradesh India
| | - Jasmine Sarkar
- Amity Institute of Neuropsychology and Neurosciences Amity University Noida Uttar Pradesh India
| | - Raafiah Izhaar
- Department of Biosciences Jamia Millia Islamia Delhi India
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Kamat PK, Khan MB, Smith C, Siddiqui S, Baban B, Dhandapani K, Hess DC. The time dimension to stroke: Circadian effects on stroke outcomes and mechanisms. Neurochem Int 2023; 162:105457. [PMID: 36442686 PMCID: PMC9839555 DOI: 10.1016/j.neuint.2022.105457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/14/2022] [Accepted: 11/19/2022] [Indexed: 11/26/2022]
Abstract
The circadian system is widely involved in the various pathological outcomes affected by time dimension changes. In the brain, the master circadian clock, also known as the "pacemaker," is present in the hypothalamus's suprachiasmatic nucleus (SCN). The SCN consists of molecular circadian clocks that operate in each neuron and other brain cells. These circadian mechanisms are controlled by the transcription and translation of specific genes such as the clock circadian regulator (Clock) and brain and muscle ARNT-Like 1 (Bmal1). Period (Per1-3) and cryptochrome (Cry1 and 2) negatively feedback and regulate the clock genes. Variations in the circadian cycle and these clock genes can affect stroke outcomes. Studies suggest that the peak stroke occurs in the morning after patients awaken from sleep, while stroke severity and poor outcomes worsen at midnight. The main risk factor associated with stroke is high blood pressure (hypertension). Blood pressure usually dips by 15-20% during sleep, but many hypertensives do not display this normal dipping pattern and are non-dippers. A sleep blood pressure is the primary determinant of stroke risk. This article discusses the possible mechanism associated with circadian rhythm and stroke outcomes.
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Affiliation(s)
- Pradip K Kamat
- Departments of Neurology, Medical College of Georgia, Augusta University, USA.
| | | | - Cameron Smith
- Departments of Neurology, Medical College of Georgia, Augusta University, USA
| | - Shahneela Siddiqui
- Departments of Neurology, Medical College of Georgia, Augusta University, USA
| | - Babak Baban
- Departments of Oral Biology, Dental College of Georgia, Augusta University, USA
| | - Krishnan Dhandapani
- Department of Neurosurgery, Medical College of Georgia, Augusta University, USA
| | - David C Hess
- Departments of Neurology, Medical College of Georgia, Augusta University, USA
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Pauls MMH, Binnie LR, Benjamin P, Betteridge S, Clarke B, Dhillon MPK, Ghatala R, Hainsworth FAH, Howe FA, Khan U, Kruuse C, Madigan JB, Moynihan B, Patel B, Pereira AC, Rostrup E, Shtaya ABY, Spilling CA, Trippier S, Williams R, Young R, Barrick TR, Isaacs JD, Hainsworth AH. The PASTIS trial: Testing tadalafil for possible use in vascular cognitive impairment. Alzheimers Dement 2022; 18:2393-2402. [PMID: 35135037 PMCID: PMC10078742 DOI: 10.1002/alz.12559] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/13/2021] [Accepted: 12/07/2021] [Indexed: 01/31/2023]
Abstract
INTRODUCTION There are few randomized clinical trials in vascular cognitive impairment (VCI). This trial tested the hypothesis that the PDE5 inhibitor tadalafil, a widely used vasodilator, increases cerebral blood flow (CBF) in older people with symptomatic small vessel disease, the main cause of VCI. METHODS In a double-blind, placebo-controlled, cross-over trial, participants received tadalafil (20 mg) and placebo on two visits ≥7 days apart (randomized to order of treatment). The primary endpoint, change in subcortical CBF, was measured by arterial spin labelling. RESULTS Tadalafil increased CBF non-significantly in all subcortical areas (N = 55, age: 66.8 (8.6) years) with greatest treatment effect within white matter hyperintensities (+9.8%, P = .0960). There were incidental treatment effects on systolic and diastolic blood pressure (-7.8, -4.9 mmHg; P < .001). No serious adverse events were observed. DISCUSSION This trial did not identify a significant treatment effect of single-administration tadalafil on subcortical CBF. To detect treatment effects may require different dosing regimens.
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Affiliation(s)
- Mathilde M H Pauls
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Lauren R Binnie
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Philip Benjamin
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Neuroradiology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Shai Betteridge
- Department of Neuropsychology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Brian Clarke
- Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Mohani-Preet K Dhillon
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Rita Ghatala
- South London Stroke Research Network, London, UK
| | - Fearghal A H Hainsworth
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Franklyn A Howe
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Usman Khan
- Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Christina Kruuse
- Department of Neurology and Neurovascular Research Unit, Herlev Gentofte Hospital, Hellerup, Denmark
| | - Jeremy B Madigan
- Department of Neuroradiology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Barry Moynihan
- Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK.,Department of Medicine, Royal College of Surgeons in Ireland, Beaumont Hospital, Dublin, Ireland
| | - Bhavini Patel
- Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Anthony C Pereira
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Egill Rostrup
- Mental Health Centre, University of Copenhagen, Glostrup, Denmark
| | - Anan B Y Shtaya
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Catherine A Spilling
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | | | | | - Robin Young
- Robertson Centre for Biostatistics, University of Glasgow, Glasgow, UK
| | - Thomas R Barrick
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK
| | - Jeremy D Isaacs
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
| | - Atticus H Hainsworth
- Molecular & Clinical Sciences Research Institute, St George's University of London, London, UK.,Department of Neurology, St George's University Hospitals NHS Foundation Trust, London, UK
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Hsu SJ, Huang HC, Pun CK, Chang CC, Chuang CL, Huang YH, Hou MC, Lee FY. Sodium-Glucose Cotransporter-2 Inhibition Exacerbates Hepatic Encephalopathy in Biliary Cirrhotic Rats. J Pharmacol Exp Ther 2022; 383:25-31. [PMID: 35926870 DOI: 10.1124/jpet.122.001289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2022] [Revised: 06/24/2022] [Accepted: 07/07/2022] [Indexed: 12/15/2022] Open
Abstract
In liver cirrhosis, hepatic inflammation and abundant portal-systemic collaterals are indicated for the development of hepatic encephalopathy. Sodium-glucose cotransporter-2 (SGLT-2) inhibitors are a type of anti-diabetic agent which exert pleiotropic and anti-inflammatory effects. Diabetes and chronic liver disease often coexist, but the influence of SGLT-2 inhibition on liver cirrhosis and hepatic encephalopathy remains unknown. This study investigated the effect of SGLT-2 inhibition on cirrhotic rats. Biliary cirrhosis was induced in Sprague-Dawley rats via common bile duct ligation. A total of two weeks of treatment with the SGLT-2 inhibitor, empagliflozin 30 mg/kg/d, was applied. The motor activities, hemodynamics, biochemistry parameters, plasma levels of vascular endothelial growth factor (VEGF), and the severity of portal-systemic collateral shunts were measured. The hepatic histopathology and protein expressions were examined. We found that empagliflozin treatment did not affect hemodynamics, liver biochemistry, or blood glucose levels in cirrhotic rats. Empagliflozin did not affect hepatic inflammation and fibrosis. The protein expression of factors related to liver injury were not influenced by empagliflozin. However, empagliflozin decreased motor activities in cirrhotic rats and increased portal-systemic collateral shunts and VEGF plasma levels. In summary, SGLT-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy, which was evidenced by a decrease in motor activity. A possible mechanism could be an increase of portal-systemic shunts related to VEGF upregulation. Therefore, empagliflozin use should be cautious in cirrhotic patients regarding the development of hepatic encephalopathy. SIGNIFICANCE STATEMENT: Sodium-glucose cotransporter-2 inhibition by empagliflozin did not ameliorate portal hypertension and hepatic inflammation in cirrhotic rats. In contrast, it exacerbated hepatic encephalopathy through increased portal-systemic shunts related to VEGF up-regulation.
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Affiliation(s)
- Shao-Jung Hsu
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Hui-Chun Huang
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Chon Kit Pun
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Ching-Chih Chang
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Chiao-Lin Chuang
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Yi-Hsiang Huang
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Ming-Chih Hou
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
| | - Fa-Yauh Lee
- Division of General Medicine (H.C.H., C.C.C., C.L.C.) and Division of Gastroenterology and Hepatology (S.J.H., Y.H.H.), Department of Medicine (C.K.P., M.C.H., F.Y.L.), Taipei Veterans General Hospital, Taipei, Taiwan and Faculty of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan (S.J.H., H.C.H., C.C.C., Y.H.H., M.C.H., F.Y.L.)
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9
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Van Daele M, Cooper SL, Pannucci P, Wragg ES, March J, de Jong I, Woolard J. Monitoring haemodynamic changes in rodent models to better inform safety pharmacology: Novel insights from in vivo studies and waveform analysis. JRSM Cardiovasc Dis 2022; 11:20480040221092893. [PMID: 35646334 PMCID: PMC9133998 DOI: 10.1177/20480040221092893] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2021] [Revised: 02/21/2022] [Accepted: 03/22/2022] [Indexed: 01/13/2023] Open
Abstract
Animal models are essential for assessing cardiovascular responses to novel therapeutics. Cardiovascular safety liabilities represent a leading cause of drug attrition and better preclinical measurements are essential to predict drug-related toxicities. Presently, radiotelemetric approaches recording blood pressure are routinely used in preclinical in vivo haemodynamic assessments, providing valuable information on therapy-associated cardiovascular effects. Nonetheless, this technique is chiefly limited to the monitoring of blood pressure and heart rate alone. Alongside these measurements, Doppler flowmetry can provide additional information on the vasculature by simultaneously measuring changes in blood flow in multiple different regional vascular beds. However, due to the time-consuming and expensive nature of this approach, it is not widely used in the industry. Currently, analysis of waveform data obtained from telemetry and Doppler flowmetry typically examines averages or peak values of waveforms. Subtle changes in the morphology and variability of physiological waveforms have previously been shown to be early markers of toxicity and pathology. Therefore, a detailed analysis of pressure and flowmetry waveforms could enhance the understanding of toxicological mechanisms and the ability to translate these preclinical observations to clinical outcomes. In this review, we give an overview of the different approaches to monitor the effects of drugs on cardiovascular parameters (particularly regional blood flow, heart rate and blood pressure) and suggest that further development of waveform analysis could enhance our understanding of safety pharmacology, providing valuable information without increasing the number of in vivo studies needed.
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Affiliation(s)
- Marieke Van Daele
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Samantha L Cooper
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Patrizia Pannucci
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Edward S Wragg
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
| | - Julie March
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
| | - Iwan de Jong
- Maastricht Instruments BV, Maastricht University, Maastricht, The Netherlands
| | - Jeanette Woolard
- Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, Queen's Medical Centre, University of Nottingham, Nottingham, UK
- Centre of Membrane Proteins and Receptors, University of Birmingham and University of Nottingham, Midlands, UK
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10
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Kroetsch JT, Lidington D, Bolz SS. The emerging significance of circadian rhythmicity in microvascular resistance. Chronobiol Int 2021; 39:465-475. [PMID: 34915783 DOI: 10.1080/07420528.2021.2009505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The Earth's rotation generates environmental oscillations (e.g., in light and temperature) that have imposed unique evolutionary pressures over millions of years. Consequently, the circadian clock, a ubiquitously expressed molecular system that aligns cellular function to these environmental cues, has become an integral component of our physiology. The resulting functional rhythms optimize and economize physiological performance: perturbing these rhythms, therefore, is frequently deleterious. This perspective article focuses on circadian rhythms in resistance artery myogenic reactivity, a key mechanism governing tissue perfusion, total peripheral resistance and systemic blood pressure. Emerging evidence suggests that myogenic reactivity rhythms are locally generated in a microvascular bed-specific manner at the level of smooth muscle cells. This implies that there is a distinct interface between the molecular clock and the signalling pathways underlying myogenic reactivity in the microvascular beds of different organs. By understanding the precise nature of these molecular links, it may become possible to therapeutically manipulate microvascular tone in an organ-specific manner. This raises the prospect that interventions for vascular pathologies that are challenging to treat, such as hypertension and brain malperfusion, can be significantly improved.
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Affiliation(s)
- Jeffrey T Kroetsch
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada
| | - Darcy Lidington
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology, University of Toronto, Toronto, Ontario, Canada.,Toronto Centre for Microvascular Medicine at the Ted Rogers Centre for Heart Research Translational Biology and Engineering Program, University of Toronto, Ontario, Canada.,Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research, University of Toronto, Toronto, Ontario, Canada
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11
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Lidington D, Wan H, Dinh DD, Ng C, Bolz SS. Circadian Rhythmicity in Cerebral Microvascular Tone Influences Subarachnoid Hemorrhage-Induced Injury. Stroke 2021; 53:249-259. [PMID: 34905942 PMCID: PMC8700310 DOI: 10.1161/strokeaha.121.036950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Circadian rhythms influence the extent of brain injury following subarachnoid hemorrhage (SAH), but the mechanism is unknown. We hypothesized that cerebrovascular myogenic reactivity is rhythmic and explains the circadian variation in SAH-induced injury.
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Affiliation(s)
- Darcy Lidington
- Department of Physiology (D.L., H.W., D.D.D., C.N., S.-S.B.), University of Toronto, Canada.,Toronto Centre for Microvascular Medicine at The Ted Rogers Centre for Heart Research Translational Biology and Engineering Program (D.L., H.W., D.D.D., C.N., S-S.B.), University of Toronto, Canada
| | - Hoyee Wan
- Department of Physiology (D.L., H.W., D.D.D., C.N., S.-S.B.), University of Toronto, Canada.,Toronto Centre for Microvascular Medicine at The Ted Rogers Centre for Heart Research Translational Biology and Engineering Program (D.L., H.W., D.D.D., C.N., S-S.B.), University of Toronto, Canada
| | - Danny D Dinh
- Department of Physiology (D.L., H.W., D.D.D., C.N., S.-S.B.), University of Toronto, Canada.,Toronto Centre for Microvascular Medicine at The Ted Rogers Centre for Heart Research Translational Biology and Engineering Program (D.L., H.W., D.D.D., C.N., S-S.B.), University of Toronto, Canada
| | - Chloe Ng
- Department of Physiology (D.L., H.W., D.D.D., C.N., S.-S.B.), University of Toronto, Canada.,Toronto Centre for Microvascular Medicine at The Ted Rogers Centre for Heart Research Translational Biology and Engineering Program (D.L., H.W., D.D.D., C.N., S-S.B.), University of Toronto, Canada
| | - Steffen-Sebastian Bolz
- Department of Physiology (D.L., H.W., D.D.D., C.N., S.-S.B.), University of Toronto, Canada.,Toronto Centre for Microvascular Medicine at The Ted Rogers Centre for Heart Research Translational Biology and Engineering Program (D.L., H.W., D.D.D., C.N., S-S.B.), University of Toronto, Canada.,Heart & Stroke/Richard Lewar Centre of Excellence for Cardiovascular Research (S-S.B.), University of Toronto, Canada
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12
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Deciphering the Interacting Mechanisms of Circadian Disruption and Alzheimer's Disease. Neurochem Res 2021; 46:1603-1617. [PMID: 33871799 DOI: 10.1007/s11064-021-03325-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 03/21/2021] [Accepted: 04/09/2021] [Indexed: 12/29/2022]
Abstract
Alzheimer's disease (AD) is one of the crucial causative factors for progressive dementia. Neuropathologically, AD is characterized by the extracellular accumulation of amyloid beta plaques and intracellular neurofibrillary tangles in cortical and limbic regions of the human brain. The circadian system is one of the many affected physiological processes in AD, the dysfunction of which may reflect in the irregularity of the sleep/wake cycle. The interplay of circadian and sleep disturbances inducing AD progression is bidirectional. Sleep-associated pathological alterations are frequently evident in AD. Understanding the interrelation between circadian disruption and AD may allow for earlier identification of AD pathogenesis as well as better suited approaches and potential therapies to combat dementia. In this article, we examine the existing literature related to the molecular mechanisms of the circadian clock and interacting mechanisms of circadian disruption and AD pathogenesis.
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13
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Bicker J, Alves G, Falcão A, Fortuna A. Timing in drug absorption and disposition: The past, present, and future of chronopharmacokinetics. Br J Pharmacol 2020; 177:2215-2239. [PMID: 32056195 DOI: 10.1111/bph.15017] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2019] [Revised: 01/05/2020] [Accepted: 01/27/2020] [Indexed: 12/20/2022] Open
Abstract
The importance of drug dosing time in pharmacokinetics, pharmacodynamics, and toxicity is receiving increasing attention from the scientific community. In spite of mounting evidence that circadian oscillations affect drug absorption, distribution, metabolism, and excretion (ADME), there remain many unanswered questions in this field and, occasionally, conflicting experimental results. Such data arise not only from translational difficulties caused by interspecies differences but also from variability in study design and a lack of understanding of how the circadian clock affects physiological factors that strongly influence ADME, namely, the expression and activity of drug transporters. Hence, the main goal of this review is to provide an updated analysis of the role of the circadian rhythm in drug absorption, distribution across blood-tissue barriers, metabolism in hepatic and extra-hepatic tissues, and hepatobiliary and renal excretion. It is expected that the research suggestions proposed here will contribute to a tissue-targeted and time-targeted pharmacotherapy.
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Affiliation(s)
- Joana Bicker
- Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.,CIBIT/ICNAS-Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal
| | - Gilberto Alves
- CICS-UBI-Health Sciences Research Centre, University of Beira Interior, Covilhã, Portugal
| | - Amílcar Falcão
- Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.,CIBIT/ICNAS-Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal
| | - Ana Fortuna
- Laboratory of Pharmacology, Faculty of Pharmacy, University of Coimbra, Coimbra, Portugal.,CIBIT/ICNAS-Coimbra Institute for Biomedical Imaging and Translational Research, University of Coimbra, Coimbra, Portugal
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14
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Circadian Rhythm and Alzheimer's Disease. Med Sci (Basel) 2018; 6:medsci6030052. [PMID: 29933646 PMCID: PMC6164904 DOI: 10.3390/medsci6030052] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 06/19/2018] [Accepted: 06/19/2018] [Indexed: 12/14/2022] Open
Abstract
Alzheimer’s disease (AD) is a neurodegenerative disorder with a growing epidemiological importance characterized by significant disease burden. Sleep-related pathological symptomatology often accompanies AD. The etiology and pathogenesis of disrupted circadian rhythm and AD share common factors, which also opens the perspective of viewing them as a mutually dependent process. This article focuses on the bi-directional relationship between these processes, discussing the pathophysiological links and clinical aspects. Common mechanisms linking both processes include neuroinflammation, neurodegeneration, and circadian rhythm desynchronization. Timely recognition of sleep-specific symptoms as components of AD could lead to an earlier and correct diagnosis with an opportunity of offering treatments at an earlier stage. Likewise, proper sleep hygiene and related treatments ought to be one of the priorities in the management of the patient population affected by AD. This narrative review brings a comprehensive approach to clearly demonstrate the underlying complexities linking AD and circadian rhythm disruption. Most clinical data are based on interventions including melatonin, but larger-scale research is still scarce. Following a pathophysiological reasoning backed by evidence gained from AD models, novel anti-inflammatory treatments and those targeting metabolic alterations in AD might prove useful for normalizing a disrupted circadian rhythm. By restoring it, benefits would be conferred for immunological, metabolic, and behavioral function in an affected individual. On the other hand, a balanced circadian rhythm should provide greater resilience to AD pathogenesis.
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15
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Lemmer B. Signal Transduction and Chronopharmacology of Regulation of Circadian Cardiovascular Rhythms in Animal Models of Human Hypertension. Heart Fail Clin 2017; 13:739-757. [DOI: 10.1016/j.hfc.2017.05.009] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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16
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Durgan DJ, Crossland RF, Bryan RM. The rat cerebral vasculature exhibits time-of-day-dependent oscillations in circadian clock genes and vascular function that are attenuated following obstructive sleep apnea. J Cereb Blood Flow Metab 2017; 37:2806-2819. [PMID: 27798273 PMCID: PMC5536790 DOI: 10.1177/0271678x16675879] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Circadian clock components oscillate in cells of the cardiovascular system. Disruption of these oscillations has been observed in cardiovascular diseases. We hypothesized that obstructive sleep apnea, which is associated with cerebrovascular diseases, disrupts the cerebrovascular circadian clock and rhythms in vascular function. Apneas were produced in rats during sleep. Following two weeks of sham or obstructive sleep apnea, cerebral arteries were isolated over 24 h for mRNA and functional analysis. mRNA expression of clock genes exhibited 24-h rhythms in cerebral arteries of sham rats (p < 0.05). Interestingly, peak expression of clock genes was significantly lower following obstructive sleep apnea (p < 0.05). Obstructive sleep apnea did not alter clock genes in the heart, or rhythms in locomotor activity. Isolated posterior cerebral arteries from sham rats exhibited a diurnal rhythm in sensitivity to luminally applied ATP, being most responsive at the beginning of the active phase (p < 0.05). This rhythm was absent in arteries from obstructive sleep apnea rats (p < 0.05). Rhythms in ATP sensitivity in sham vessels were absent, and not different from obstructive sleep apnea, following treatment with L-NAME and indomethacin. We conclude that cerebral arteries possess a functional circadian clock and exhibit a diurnal rhythm in vasoreactivity to ATP. Obstructive sleep apnea attenuates these rhythms in cerebral arteries, potentially contributing to obstructive sleep apnea-associated cerebrovascular disease.
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Affiliation(s)
- David J Durgan
- Department of Anesthesiology, Baylor College of Medicine, Houston, USA
| | - Randy F Crossland
- Department of Anesthesiology, Baylor College of Medicine, Houston, USA
| | - Robert M Bryan
- Department of Anesthesiology, Baylor College of Medicine, Houston, USA
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17
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DeLorenzo C, Gallezot JD, Gardus J, Yang J, Planeta B, Nabulsi N, Ogden RT, Labaree DC, Huang YH, Mann JJ, Gasparini F, Lin X, Javitch JA, Parsey RV, Carson RE, Esterlis I. In vivo variation in same-day estimates of metabotropic glutamate receptor subtype 5 binding using [ 11C]ABP688 and [ 18F]FPEB. J Cereb Blood Flow Metab 2017; 37:2716-2727. [PMID: 27742888 PMCID: PMC5536783 DOI: 10.1177/0271678x16673646] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2016] [Revised: 08/02/2016] [Accepted: 09/12/2016] [Indexed: 01/11/2023]
Abstract
Positron emission tomography tracers [11C]ABP688 and [18F]FPEB target the metabotropic glutamate receptor subtype 5 providing quantification of the brain glutamatergic system in vivo. Previous [11C]ABP688 positron emission tomography human test-retest studies indicate that, when performed on the same day, significant binding increases are observed; however, little deviation is reported when scans are >7 days apart. Due to the small cohorts examined previously (eight and five males, respectively), we aimed to replicate the same-day test-retest studies in a larger cohort including both males and females. Results confirmed large within-subject binding differences (ranging from -23% to 108%), suggesting that measurements are greatly affected by study design. We further investigated whether this phenomenon was specific to [11C]ABP688. Using [18F]FPEB and methodology that accounts for residual radioactivity from the test scan, four subjects were scanned twice on the same day. In these subjects, binding estimates increased between 5% and 39% between scans. Consistent with [11C]ABP688, mean absolute test-retest variability was previously reported as <12% when scans were >21 days apart. This replication study and pilot extension to [18F]FPEB suggest that observed within-day binding variation may be due to characteristics of mGluR5; for example, diurnal variation in mGluR5 may affect measurement of this receptor.
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Affiliation(s)
- Christine DeLorenzo
- Department of Psychiatry, Stony Brook University, Stony Brook, USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, USA
- Department of Psychiatry, Columbia University, New York, USA
| | | | - John Gardus
- Department of Psychiatry, Stony Brook University, Stony Brook, USA
| | - Jie Yang
- Department of Preventive Medicine, Stony Brook University, Stony Brook, USA
| | - Beata Planeta
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
| | - Nabeel Nabulsi
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
| | - R Todd Ogden
- Department of Psychiatry, Columbia University, New York, USA
| | - David C Labaree
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
| | - Yiyun H Huang
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
| | - J John Mann
- Department of Psychiatry, Columbia University, New York, USA
| | | | - Xin Lin
- Department of Psychiatry, Columbia University, New York, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, USA
| | - Jonathan A Javitch
- Department of Psychiatry, Columbia University, New York, USA
- Division of Molecular Therapeutics, New York State Psychiatric Institute, New York, USA
- Department of Pharmacology, Columbia University, New York, USA
| | - Ramin V Parsey
- Department of Psychiatry, Stony Brook University, Stony Brook, USA
- Department of Biomedical Engineering, Stony Brook University, Stony Brook, USA
- Department of Radiology, Stony Brook University, Stony Brook, USA
| | - Richard E Carson
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
- Department of Biomedical Engineering, Yale University, New Haven, USA
| | - Irina Esterlis
- Department of Radiology and Biomedical Imaging, Yale University, New Haven, USA
- Department of Psychiatry, Yale University, New Haven, USA
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18
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Savolainen H, Meerlo P, Elsinga PH, Windhorst AD, Dierckx RA, Colabufo NA, van Waarde A, Luurtsema G. P-glycoprotein Function in the Rodent Brain Displays a Daily Rhythm, a Quantitative In Vivo PET Study. AAPS JOURNAL 2016; 18:1524-1531. [DOI: 10.1208/s12248-016-9973-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2016] [Accepted: 08/08/2016] [Indexed: 12/21/2022]
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19
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Fan AP, Jahanian H, Holdsworth SJ, Zaharchuk G. Comparison of cerebral blood flow measurement with [15O]-water positron emission tomography and arterial spin labeling magnetic resonance imaging: A systematic review. J Cereb Blood Flow Metab 2016; 36:842-61. [PMID: 26945019 PMCID: PMC4853843 DOI: 10.1177/0271678x16636393] [Citation(s) in RCA: 105] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2015] [Revised: 01/19/2016] [Accepted: 02/04/2016] [Indexed: 11/16/2022]
Abstract
Noninvasive imaging of cerebral blood flow provides critical information to understand normal brain physiology as well as to identify and manage patients with neurological disorders. To date, the reference standard for cerebral blood flow measurements is considered to be positron emission tomography using injection of the [(15)O]-water radiotracer. Although [(15)O]-water has been used to study brain perfusion under normal and pathological conditions, it is not widely used in clinical settings due to the need for an on-site cyclotron, the invasive nature of arterial blood sampling, and experimental complexity. As an alternative, arterial spin labeling is a promising magnetic resonance imaging technique that magnetically labels arterial blood as it flows into the brain to map cerebral blood flow. As arterial spin labeling becomes more widely adopted in research and clinical settings, efforts have sought to standardize the method and validate its cerebral blood flow values against positron emission tomography-based cerebral blood flow measurements. The purpose of this work is to critically review studies that performed both [(15)O]-water positron emission tomography and arterial spin labeling to measure brain perfusion, with the aim of better understanding the accuracy and reproducibility of arterial spin labeling relative to the positron emission tomography reference standard.
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Affiliation(s)
- Audrey P Fan
- Department of Radiology, Stanford University, Stanford, CA, USA
| | | | | | - Greg Zaharchuk
- Department of Radiology, Stanford University, Stanford, CA, USA
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20
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Carver KA, Lourim D, Tryba AK, Harder DR. Rhythmic expression of cytochrome P450 epoxygenases CYP4x1 and CYP2c11 in the rat brain and vasculature. Am J Physiol Cell Physiol 2014; 307:C989-98. [PMID: 25055826 DOI: 10.1152/ajpcell.00401.2013] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Mammals have circadian variation in blood pressure, heart rate, vascular tone, thrombotic tendency, and cerebral blood flow (CBF). These changes may be in part orchestrated by circadian variation in clock gene expression within cells comprising the vasculature that modulate blood flow (e.g., fibroblasts, cerebral vascular smooth muscle cells, astrocytes, and endothelial cells). However, the downstream mechanisms that underlie circadian changes in blood flow are unknown. Cytochrome P450 epoxygenases (Cyp4x1 and Cyp2c11) are expressed in the brain and vasculature and metabolize arachidonic acid (AA) to form epoxyeicosatrienoic acids (EETs). EETs are released from astrocytes, neurons, and vascular endothelial cells and act as potent vasodilators, increasing blood flow. EETs released in response to increases in neural activity evoke a corresponding increase in blood flow known as the functional hyperemic response. We examine the hypothesis that Cyp2c11 and Cyp4x1 expression and EETs production vary in a circadian manner in the rat brain and cerebral vasculature. RT-PCR revealed circadian/diurnal expression of clock and clock-controlled genes as well as Cyp4x1 and Cyp2c11, within the rat hippocampus, middle cerebral artery, inferior vena cava, hippocampal astrocytes and rat brain microvascular endothelial cells. Astrocyte and endothelial cell culture experiments revealed rhythmic variation in Cyp4x1 and Cyp2c11 gene and protein expression with a 12-h period and parallel rhythmic production of EETs. Our data suggest there is circadian regulation of Cyp4x1 and Cyp2c11 gene expression. Such rhythmic EETs production may contribute to circadian changes in blood flow and alter risk of adverse cardiovascular events throughout the day.
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Affiliation(s)
- Koryn A Carver
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - David Lourim
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and
| | - Andrew K Tryba
- Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin
| | - David R Harder
- Cardiovascular Research Center, Medical College of Wisconsin, Milwaukee, Wisconsin; Department of Physiology, Medical College of Wisconsin, Milwaukee, Wisconsin; and Clement J. Zablocki VA Medical Center, Milwaukee, Wisconsin
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21
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Rakesh V, Stallings JD, Helwig BG, Leon LR, Jackson DA, Reifman J. A 3-D mathematical model to identify organ-specific risks in rats during thermal stress. J Appl Physiol (1985) 2013; 115:1822-37. [DOI: 10.1152/japplphysiol.00589.2013] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Early prediction of the adverse outcomes associated with heat stress is critical for effective management and mitigation of injury, which may sometimes lead to extreme undesirable clinical conditions, such as multiorgan dysfunction syndrome and death. Here, we developed a computational model to predict the spatiotemporal temperature distribution in a rat exposed to heat stress in an attempt to understand the correlation between heat load and differential organ dysfunction. The model includes a three-dimensional representation of the rat anatomy obtained from medical imaging and incorporates the key mechanisms of heat transfer during thermoregulation. We formulated a novel approach to estimate blood temperature by accounting for blood mixing from the different organs and to estimate the effects of the circadian rhythm in body temperature by considering day-night variations in metabolic heat generation and blood perfusion. We validated the model using in vivo core temperature measurements in control and heat-stressed rats and other published experimental data. The model predictions were within 1 SD of the measured data. The liver demonstrated the greatest susceptibility to heat stress, with the maximum temperature reaching 2°C higher than the measured core temperature and 95% of its volume exceeding the targeted experimental core temperature. Other organs also attained temperatures greater than the core temperature, illustrating the need to monitor multiple organs during heat stress. The model facilitates the identification of organ-specific risks during heat stress and has the potential to aid in the development of improved clinical strategies for thermal-injury prevention and management.
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Affiliation(s)
- Vineet Rakesh
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, Maryland
| | - Jonathan D. Stallings
- Biomarkers Program, United States Army Center for Environmental Health Research, Fort Detrick, Maryland; and
| | - Bryan G. Helwig
- Thermal Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - Lisa R. Leon
- Thermal Mountain Medicine Division, United States Army Research Institute of Environmental Medicine, Natick, Massachusetts
| | - David A. Jackson
- Biomarkers Program, United States Army Center for Environmental Health Research, Fort Detrick, Maryland; and
| | - Jaques Reifman
- Department of Defense Biotechnology High Performance Computing Software Applications Institute, Telemedicine and Advanced Technology Research Center, United States Army Medical Research and Materiel Command, Fort Detrick, Maryland
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22
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van Golen LW, Kuijer JP, Huisman MC, IJzerman RG, Barkhof F, Diamant M, Lammertsma AA. Quantification of cerebral blood flow in healthy volunteers and type 1 diabetic patients: Comparison of MRI arterial spin labeling and [15O]H2O positron emission tomography (PET). J Magn Reson Imaging 2013; 40:1300-9. [DOI: 10.1002/jmri.24484] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Accepted: 09/28/2013] [Indexed: 11/06/2022] Open
Affiliation(s)
- Larissa W. van Golen
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Joost P.A. Kuijer
- Department of Physics and Medical Technology, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Marc C. Huisman
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Richard G. IJzerman
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Frederik Barkhof
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
| | - Michaela Diamant
- Diabetes Center/ Department of Internal Medicine; VU University Medical Center; Amsterdam The Netherlands
| | - Adriaan A. Lammertsma
- Department of Radiology & Nuclear Medicine, Neuroscience Campus Amsterdam; VU University Medical Center; Amsterdam The Netherlands
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23
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Halberg F, Powell D, Otsuka K, Watanabe Y, Beaty LA, Rosch P, Czaplicki J, Hillman D, Schwartzkopff O, Cornelissen G. Diagnosing vascular variability anomalies, not only MESOR-hypertension. Am J Physiol Heart Circ Physiol 2013; 305:H279-94. [PMID: 23709604 DOI: 10.1152/ajpheart.00212.2013] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronobiology is the study of biological rhythms. Chronomics investigates interactions with environmental cycles in a genetically coded autoresonance of the biosphere with wrangling space and terrestrial weather. Analytical global and local methods applied to human blood pressure records of around-the-clock measurements covering decades detect physiological-physical interactions, a small yet measurable response to solar and terrestrial magnetism. The chronobiological and chronomic interpretation of ambulatory blood pressure monitoring (C-ABPM) records in the light of time-specified reference values derived from healthy peers matched by sex and age identify vascular variability anomalies (VVAs) for an assessment of cardio-, cerebro-, and renovascular disease risk. Even within the conventionally accepted normal range, VVAs have been associated with a statistically significant increase in risk. Long-term C-ABPM records help to "know ourselves," serving for relief of psychological and other strain once transient VVAs are linked to the source of a load, prompting adjustment of one's lifestyle for strain reduction. Persistent circadian VVAs can be treated, sometimes by no more than a change in timing of the daily administration of antihypertensive medication. Circadian VVA assessment is an emergency worldwide, prompted in the United States by 1,000 deaths per day every day from problems related to blood pressure. While some heads of state met under United Nation and World Health Organization sponsorship to declare that noncommunicable diseases are a slow-motion disaster, a resolution has been drafted to propose C-ABPM as an added tool complementing purely physical environmental monitoring to contribute also to the understanding of social and natural as well as personal cataclysms.
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Affiliation(s)
- Franz Halberg
- University of Minnesota Academic Health Center, Minneapolis, MN 55455, USA
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24
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Takuwa H, Autio J, Nakayama H, Matsuura T, Obata T, Okada E, Masamoto K, Kanno I. Reproducibility and variance of a stimulation-induced hemodynamic response in barrel cortex of awake behaving mice. Brain Res 2010; 1369:103-11. [PMID: 21070750 DOI: 10.1016/j.brainres.2010.11.007] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 11/03/2010] [Indexed: 12/14/2022]
Abstract
The present work evaluated the reproducibility and variance of the cerebral blood flow (CBF) response to natural whisker stimulation in the barrel cortex of awake behaving mice. The animal was placed on an air float ball that allowed the animal to walk, while the head of the animal was fixed in a custom-made stereotactic apparatus. Dynamic CBF changes in the barrel cortex and animal locomotion were simultaneously monitored with laser-Doppler flowmetry (LDF) and an optical motion sensor that detected the rotation distance of the ball, respectively. Whisker stimulation-induced CBF measured under daytime and nighttime conditions showed consistent responses (24% and 23% of the pre-stimulus baseline, respectively), whereas the amount of locomotion was 1.4 times higher during nighttime relative to daytime. Repeated longitudinal experiments over 7 days showed a reproducible, evoked CBF (13-26% relative to the baseline among 7 animals). The mean of the variance coefficient (i.e., standard deviation divided by mean) across multiple days was 0.11 and 0.75 for evoked CBF and locomotion, respectively. These results showed reproducible and reliable measurements of longitudinal CBF response in behaving mice regardless of day-to-day variations in locomotion. Furthermore, we confirmed that the CBF response to whisker stimulation was well localized and reproducible, measured with laser speckle imaging under awake condition. The results further show the capability of long-term hemodynamic imaging in normal and disease-model mice, which is of particular importance for understanding the longitudinal changes and plasticity of neurovascular coupling and behavioral performances such as during growth, development and aging.
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Affiliation(s)
- Hiroyuki Takuwa
- Department of Biophysics, Molecular Imaging Center, National Institute of Radiological Sciences, 4-9-1 Anagawa, Chiba 263-8555, Japan
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Jensen EC, Bennet L, Guild SJ, Booth LC, Stewart J, Gunn AJ. The role of the neural sympathetic and parasympathetic systems in diurnal and sleep state-related cardiovascular rhythms in the late-gestation ovine fetus. Am J Physiol Regul Integr Comp Physiol 2009; 297:R998-R1008. [DOI: 10.1152/ajpregu.90979.2008] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The efferent mechanisms mediating the well-known diurnal cardiovascular rhythms in the late-gestation fetus are only partially understood. In the present study, we evaluated the contribution of the parasympathetic and sympathetic nervous systems (SNS) to these rhythms. Chronically instrumented fetal sheep at a mean (SE) of 122 ( 1 ) days gestation (term is 147 days) underwent either chemical sympathectomy with 6-hydroxydopamine the day after surgery ( n = 8), vagotomy at surgery ( n = 8), or were sham controls ( n = 8). Fetal heart rate (HR), fetal HR variability (HRV), mean arterial blood pressure (MAP), carotid blood flow (CaBF), electrocorticogram (ECoG) activity, and nuchal activity were measured continuously for 24 h. Changes between sleep states were determined in a 6-h interval. Control fetal sheep showed consistent diurnal rhythms in fetal HR, HRV, MAP, and CaBF, with maximal activity in the evening, but not in nuchal activity. Sympathectomy was associated with a significant reduction of both fetal HR and HRV, while vagotomy was associated with a fall in fetal HRV ( P < 0.05) but no change in HR. Despite this, most animals in the two intervention groups still showed diurnal rhythms for fetal HR, HRV, MAP, and CaBF, although peak HR may have been delayed in the sympathectomy group (mean 02:22 vs. 23:54 h in controls, P = 0.06). There was no effect of either intervention on sleep state cycling, although state-related cardiovascular rhythms were significantly modulated. These data indicate that, neither the SNS nor vagal activity, in isolation at least, is essential for generating cardiovascular diurnal rhythms in the late-gestation fetus.
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Affiliation(s)
- Ellen C. Jensen
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Laura Bennet
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Sarah-Jane Guild
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Lindsea C. Booth
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Joanna Stewart
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
| | - Alistair J. Gunn
- Department of Physiology, Faculty of Medical and Health Sciences, The University of Auckland, Auckland, New Zealand
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Hajjar I, Selim M, Novak P, Novak V. The relationship between nighttime dipping in blood pressure and cerebral hemodynamics in nonstroke patients. J Clin Hypertens (Greenwich) 2008; 9:929-36. [PMID: 18046099 DOI: 10.1111/j.1524-6175.2007.07342.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Inadequate dipping in nighttime blood pressure (BP) is associated with cerebrovascular disease. The authors aimed to determine whether inadequate nocturnal dipping was associated with abnormalities in cerebrovascular hemodynamics in individuals without stroke. Participants in this study underwent 24-hour ambulatory BP monitoring followed by morning transcranial Doppler measurements of blood flow velocities (BFVs) in the middle cerebral artery during supine rest, head-up tilt, hypocapnia, and hypercapnia. Nighttime BP decline by <10% was considered nondipping. Of the 102 nonstroke participants (mean age, 53.6 years), 35 (34%) were dippers. Although nondippers had similar BFV and cerebrovascular resistance (CVR) while supine, they had a lower BFV (P=.04) and greater CVR (P=.02) during head-up tilt compared with dippers. Moreover, greater nighttime dipping in both systolic BP (P=.006) and diastolic BP (P=.03) were associated with higher daytime BFV and lower CVR (P=.01 for systolic BP; P=.02 for diastolic BP). Inadequate nocturnal BP dipping is associated with lower daytime cerebral blood flow, especially during head-up tilt.
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Affiliation(s)
- Ihab Hajjar
- Beth Israel Deaconess Medical Center, Institute for Aging Research at Hebrew SeniorLife, Boston, MA 02131, USA.
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Lemmer B. Circadian Rhythm Regulations of the Cardiovascular System in Rats and Mice. ACTA ACUST UNITED AC 2007; 26:30-2. [DOI: 10.1109/emb.2007.907090] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Chassard D, Duflo F, de Queiroz Siqueira M, Allaouchiche B, Boselli E. Chronobiology and anaesthesia. Curr Opin Anaesthesiol 2007; 20:186-90. [PMID: 17479018 DOI: 10.1097/aco.0b013e328136c55e] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
PURPOSE OF REVIEW It has been shown that biological rhythms influence the pharmacology and effects of anaesthetic agents such as local anaesthetics, hypnotics and muscle relaxants. This review discusses the latest findings and their consequences for anaesthesiological practice. RECENTS FINDINGS: Opioids and new local anaesthetics exhibit circadian changes when they are injected into spinal or epidural spaces for labour pain analgesia. Other studies have demonstrated that propofol and ketamine have maximal duration of action when they are injected during a period of rest in animals (at night in humans). It has been also shown that propofol can perturb the central circadian pacemaker and so cause a phase-shifted advance in effect on activity in rats. SUMMARY Although studies are lacking for most newer anaesthetic agents used in humans, recent findings emphasize once again that chronobiology should be considered in studies of anaesthetic drugs. Circadian rhythms should be considered in pharmacokinetic and pharmacodynamic analyses so that proper research protocols can be designed. The implications of chronobiology for the practice of clinical anaesthesia are probably of lesser importance because of the use of patient-controlled devices for pain management, monitoring of muscle paralysis and depth of anaesthesia monitors.
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Affiliation(s)
- Dominique Chassard
- Service d'Anesthésie-Réanimation, Hôpital de l'Hôtel-Dieu, Lyon, University of Lyon, Lyon, France
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