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Cipolla MJ, Tremble SM, DeLance N, Johnson AC. Worsened Stroke Outcome in a Model of Preeclampsia is Associated With Poor Collateral Flow and Oxidative Stress. Stroke 2023; 54:354-363. [PMID: 36689585 PMCID: PMC9888018 DOI: 10.1161/strokeaha.122.041637] [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: 10/24/2022] [Accepted: 12/15/2022] [Indexed: 01/24/2023]
Abstract
BACKGROUND Preeclampsia increases the incidence of maternal stroke, a devastating condition that is on the rise. We investigated stroke outcome in a model of experimental preeclampsia with and without treatment with clinically relevant doses of magnesium sulfate (experimental preeclampsia+MgSO4) compared to normal late-pregnant and nonpregnant rats. METHODS Transient middle cerebral artery occlusion was used to induce focal stroke for either 1.5 or 3 hours. Infarct volume and hemorrhagic transformation were determined as measures of stroke outcome. Changes in core middle cerebral artery and collateral flow were measured by dual laser Doppler. The relationship between middle cerebral artery perfusion deficit and infarction was used as a measure of ischemic tolerance. Oxidative stress and endothelial dysfunction were measured by 3-nitrotyrosine and 8-isoprostane, in brain and serum, respectively. RESULTS Late-pregnant animals had robust collateral flow and greater ischemic tolerance of brain tissue, whereas experimental preeclampsia had greater infarction that was related to poor collateral flow, endothelial dysfunction, and oxidative stress. Importantly, pregnancy appeared preventative of hemorrhagic transformation as it occurred only in nonpregnant animals. MgSO4 did not provide benefit to experimental preeclampsia animals for infarction. CONCLUSIONS Stroke outcome was worse in a model of preeclampsia. As preeclampsia increases the risk of future stroke and cardiovascular disease, it is worth understanding the influence of preeclampsia on the material brain and factors that might potentiate injury both during the index pregnancy and years postpartum.
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Affiliation(s)
- Marilyn J. Cipolla
- Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
- Department Obstetrics, Gynecology & Reproductive Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
- Department Pharmacology, University of Vermont Larner College of Medicine, Burlington, VT, USA
- Department of Electrical and Biological Engineering, College of Engineering and Mathematical Sciences, University of Vermont, Burlington, VT USA
| | - Sarah M. Tremble
- Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Nicole DeLance
- Department Pathology, University of Vermont Larner College of Medicine, Burlington, VT, USA
| | - Abbie C. Johnson
- Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT, USA
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2
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Fishel Bartal M, Sibai BM. Eclampsia in the 21st century. Am J Obstet Gynecol 2022; 226:S1237-S1253. [PMID: 32980358 DOI: 10.1016/j.ajog.2020.09.037] [Citation(s) in RCA: 66] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 09/14/2020] [Accepted: 09/22/2020] [Indexed: 12/12/2022]
Abstract
The reported incidence of eclampsia is 1.6 to 10 per 10,000 deliveries in developed countries, whereas it is 50 to 151 per 10,000 deliveries in developing countries. In addition, low-resource countries have substantially higher rates of maternal and perinatal mortalities and morbidities. This disparity in incidence and pregnancy outcomes may be related to universal access to prenatal care, early detection of preeclampsia, timely delivery, and availability of healthcare resources in developed countries compared to developing countries. Because of its infrequency in developed countries, many obstetrical providers and maternity units have minimal to no experience in the acute management of eclampsia and its complications. Therefore, clear protocols for prevention of eclampsia in those with severe preeclampsia and acute treatment of eclamptic seizures at all levels of healthcare are required for better maternal and neonatal outcomes. Eclamptic seizure will occur in 2% of women with preeclampsia with severe features who are not receiving magnesium sulfate and in <0.6% in those receiving magnesium sulfate. The pathogenesis of an eclamptic seizure is not well understood; however, the blood-brain barrier disruption with the passage of fluid, ions, and plasma protein into the brain parenchyma remains the leading theory. New data suggest that blood-brain barrier permeability may increase by circulating factors found in preeclamptic women plasma, such as vascular endothelial growth factor and placental growth factor. The management of an eclamptic seizure will include supportive care to prevent serious maternal injury, magnesium sulfate for prevention of recurrent seizures, and promoting delivery. Although routine imagining following an eclamptic seizure is not recommended, the classic finding is referred to as the posterior reversible encephalopathy syndrome. Most patients with posterior reversible encephalopathy syndrome will show complete resolution of the imaging finding within 1 to 2 weeks, but routine imaging follow-up is unnecessary unless there are findings of intracranial hemorrhage, infraction, or ongoing neurologic deficit. Eclampsia is associated with increased risk of maternal mortality and morbidity, such as placental abruption, disseminated intravascular coagulation, pulmonary edema, aspiration pneumonia, cardiopulmonary arrest, and acute renal failure. Furthermore, a history of eclamptic seizures may be related to long-term cardiovascular risk and cognitive difficulties related to memory and concentration years after the index pregnancy. Finally, limited data suggest that placental growth factor levels in women with preeclampsia are superior to clinical markers in prediction of adverse pregnancy outcomes. This data may be extrapolated to the prediction of eclampsia in future studies. This summary of available evidence provides data and expert opinion on possible pathogenesis of eclampsia, imaging findings, differential diagnosis, and stepwise approach regarding the management of eclampsia before delivery and after delivery as well as current recommendations for the prevention of eclamptic seizures in women with preeclampsia.
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Affiliation(s)
- Michal Fishel Bartal
- Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX.
| | - Baha M Sibai
- Division of Maternal-Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX
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3
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Brislane Á, Steinback CD, Davenport MH. The Nine Month Stress Test: Pregnancy and Exercise - Similarities and Interactions. Can J Cardiol 2021; 37:2014-2025. [PMID: 34534622 DOI: 10.1016/j.cjca.2021.09.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 08/18/2021] [Accepted: 09/03/2021] [Indexed: 11/29/2022] Open
Abstract
Of all physiological systems, the cardiovascular system takes on the most profound adaptation in pregnancy to support fetal growth and development. The adaptations that arise are systemic and involve structural and functional changes that can be observed at the cerebral, central, peripheral, and microvascular beds. This includes, although is not limited to increased heart rate, stroke volume and cardiac output with negligible change to blood pressure, reductions in vascular resistance and cerebral blood flow velocity, systemic artery enlargement, enhanced endothelial function. All of this takes place to accommodate blood volume expansion and ensure adequate fetal and maternal oxygen delivery. In some instances, the demand placed on the vasculature can manifest as cardiovascular maladaptation and thus, cardiovascular complications can arise. Exercise is recommended in pregnancy because of its powerful ability to reduce the incidence and severity of cardiovascular complications in pregnancy. However, the mechanism by which it acts is poorly understood. The first aim of this review is to describe the systemic adaptations that take place in pregnancy. Secondly, this review aims to describe the influence of exercise on these systemic adaptations. It is anticipated that this review can comprehensively capture the extent of knowledge in this area while identifying areas that warrant further investigation.
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Affiliation(s)
- Áine Brislane
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada
| | - Craig D Steinback
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada
| | - Margie H Davenport
- Program for Pregnancy & Postpartum Health, Neurovascular Health Lab, Faculty of Kinesiology, Sport, and Recreation, Women and Children's Health Research Institute, Alberta Diabetes Institute, University of Alberta, Alberta, Canada.
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4
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Physiology of the cerebrovascular adaptation to pregnancy. HANDBOOK OF CLINICAL NEUROLOGY 2021. [PMID: 32736760 DOI: 10.1016/b978-0-444-64239-4.00004-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2023]
Abstract
The adaptation of the cerebral circulation to pregnancy is unique compared with other organs and circulatory systems, because the brain requires relatively constant blood flow and water and solute composition to maintain homeostasis. Thus, a major adaptation of the maternal cerebrovasculature to pregnancy is to maintain normalcy in the face of expanded plasma volume, increased cardiac output, and high levels of permeability factors. In this chapter, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier (BBB), which protect the maternal brain from changes in BBB permeability. Further, pregnancy-induced changes in the structure and function of cerebral arteries, arterioles, and veins will be discussed as they relate to cerebral vascular resistance, hemodynamics, and cerebral blood flow autoregulation.
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5
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Beighley A, Glynn R, Scullen T, Mathkour M, Werner C, Berry JF, Carr C, Abou-Al-Shaar H, Aysenne A, Nerva JD, Dumont AS. Aneurysmal subarachnoid hemorrhage during pregnancy: a comprehensive and systematic review of the literature. Neurosurg Rev 2021; 44:2511-2522. [PMID: 33409763 DOI: 10.1007/s10143-020-01457-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 11/10/2020] [Accepted: 12/07/2020] [Indexed: 11/30/2022]
Abstract
Aneurysmal subarachnoid hemorrhage (aSAH) is an emergent condition requiring rapid intervention and prolonged monitoring. There are few recommendations regarding the management of aSAH in pregnancy. We identified all available literature and compiled management decisions as well as reported outcomes through a systematic literature review without meta-analysis to provide recommendations for management of aSAH during pregnancy. We included a total of 23 articles containing 54 cases of pregnancy-related aSAH in our review. From these reports and other literature, we evaluated information on aSAH pathophysiology, diagnosis, and management with respect to pregnancy. Early transfer to an appropriate facility with neurocritical care, a high-risk obstetric service, and a neurosurgery team available is crucial for the management of aSAH in pregnancy. Intensive monitoring and a multidisciplinary approach remain fundamental to ensure maternal and fetal health.
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Affiliation(s)
- Adam Beighley
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA
| | - Ryan Glynn
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA.,Department of Neurological Surgery, Ochsner Medical Center, New Orleans, LA, USA
| | - Tyler Scullen
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA.,Department of Neurological Surgery, Ochsner Medical Center, New Orleans, LA, USA
| | - Mansour Mathkour
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA. .,Department of Neurological Surgery, Ochsner Medical Center, New Orleans, LA, USA. .,Neurosurgery Division, Surgery Department, Jazan University, Jazan, Kingdom of Saudi Arabia.
| | - Cassidy Werner
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA
| | - John F Berry
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA.,Department of Neurological Surgery, Ochsner Medical Center, New Orleans, LA, USA
| | - Christopher Carr
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA
| | - Hussam Abou-Al-Shaar
- Department of Neurological Surgery, University of Pittsburgh Medical Center, Pittsburgh, PA, USA
| | - Aimee Aysenne
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA.,Department of Neurocritical Care, Tulane Medical Center, New Orleans, LA, USA
| | - John D Nerva
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA
| | - Aaron S Dumont
- Department of Neurological Surgery, Tulane University, New Orleans, LA, USA. .,Department of Neurological Surgery, Ochsner Medical Center, New Orleans, LA, USA.
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6
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Maeda KJ, McClung DM, Showmaker KC, Warrington JP, Ryan MJ, Garrett MR, Sasser JM. Endothelial cell disruption drives increased blood-brain barrier permeability and cerebral edema in the Dahl SS/jr rat model of superimposed preeclampsia. Am J Physiol Heart Circ Physiol 2020; 320:H535-H548. [PMID: 33275518 DOI: 10.1152/ajpheart.00383.2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Preeclampsia is characterized by increases in blood pressure and proteinuria in late pregnancy, and neurological symptoms can appear in the form of headaches, blurred vision, cerebral edema, and, in the most severe cases, seizures (eclampsia). The causes for these cerebral manifestations remain unknown, so the use of animal models that mimic preeclampsia is essential to understanding its pathogenesis. The Dahl salt-sensitive (Dahl SS/jr) rat model develops spontaneous preeclampsia superimposed on chronic hypertension; therefore, we hypothesized that the Dahl SS/jr rat would display cerebrovascular features similar to those seen in human preeclampsia. Furthermore, we predicted that this model would allow for the identification of mechanisms underlying these changes. The pregnant Dahl SS/jr rat displayed increased cerebral edema and blood-brain barrier disruption despite tighter control of cerebral blood flow autoregulation and vascular smooth muscle myogenic tone. Analysis of cerebral endothelial cell morphology revealed increased opening of tight junctions, basement membrane dissolution, and vesicle formation. RNAseq analysis identified that genes related to endothelial cell tight junctions and blood-brain barrier integrity were differentially expressed in cerebral vessels from pregnant Dahl SS/jr compared with healthy pregnant Sprague Dawley rats. Overall, our data reveal new insights into mechanisms involved in the cerebrovascular dysfunction of preeclampsia.NEW & NOTEWORTHY This study uses the Dahl SS/jr rat as a preclinical model of spontaneous superimposed preeclampsia to demonstrate uncoupling of cerebral vascular permeability and blood-brain barrier disruption from cerebral blood flow autoregulatory dysfunction and myogenic tone. Additionally, the data presented in this study lay the foundational framework on which future experiments assessing specific transcellular transport components such as individual transporter protein expression and components of the vesicular transport system (caveolae) can be built to help reveal a potential direct mechanistic insight into the causes of cerebrovascular complications during preeclamptic pregnancies.
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Affiliation(s)
- Kenji J Maeda
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Daniel M McClung
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Physiology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Kurt C Showmaker
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Data Science, University of Mississippi Medical Center, Jackson, Mississippi
| | - Junie P Warrington
- Department of Neurology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael J Ryan
- Department of Physiology, University of Mississippi Medical Center, Jackson, Mississippi
| | - Michael R Garrett
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi.,Department of Medicine (Nephrology), University of Mississippi Medical Center, Jackson, Mississippi
| | - Jennifer M Sasser
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, Jackson, Mississippi
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7
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Brislane Á, Jones H, Holder SM, Low DA, Hopkins ND. The Effect of Exercise During Pregnancy on Maternal and Offspring Vascular Outcomes: a Pilot Study. Reprod Sci 2020; 28:510-523. [PMID: 33258064 PMCID: PMC7808996 DOI: 10.1007/s43032-020-00302-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/20/2020] [Indexed: 01/28/2023]
Abstract
The aim of this pilot study is to obtain estimates for the change in maternal cerebrovascular (primary) and offspring vascular structure (secondary) during healthy pregnancy that includes structured exercise. Eighteen pregnant women self-assigned to a moderate-intensity aerobic exercise intervention or a control group. Maternal cerebral blood flow (CBF) at the middle cerebral artery, cerebro- and peripheral-vascular function was assessed at the end of each trimester. Offspring carotid artery intima-media thickness (IMT) was measured within 12 weeks of birth. For exploratory purposes, we performed statistical analysis to provide estimates of the change for primary and secondary outcome variables. Maternal CBF reduced (− 8 cm s−1 [− 14 to − 2]) with evidence of change to cerebral autoregulation (normalised gain: 0.12 %cm s−1% mmHg−1mmHg/% [− 0.18 to 0.40]) during pregnancy. Offspring carotid IMT was smaller in the exercise group (− 0.04 mm [− 0.12–0.03]) compared with controls. Based upon this data, a sample size of 33 and 57 in each group is required for low-frequency normalised gain and offspring IMT, respectively. This would provide 90% power to detect statistically significant (P < 0.05) between group differences in a randomised controlled trial. CBF is reduced in pregnancy, possibly due to reduced vascular resistance and altered maternal cerebral autoregulation. Maternal exercise had negligible effects on cerebrovascular adaptation to pregnancy, but we observed lower offspring carotid artery wall thickness following maternal exercise. Our directional findings and sample size estimations should be explored in a fully powered randomised control trial. Clinical trial registration: The trial was registered on March 14th at https://register.clinicaltrials.gov (NCT03079258). Participant enrolment began on 3rd April 2016.
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Affiliation(s)
- Áine Brislane
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK.
- School of Sport, York St. John University, Lord Mayor's Walk, York, YO31 7EX, UK.
| | - Helen Jones
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Sophie M Holder
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - David A Low
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
| | - Nicola D Hopkins
- Research Institute of Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, L3 3AF, UK
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8
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Fan JL, O’Donnell T, Lanford J, Croft K, Watson E, Smyth D, Koch H, Wong LK, Tzeng YC. Dietary nitrate reduces blood pressure and cerebral artery velocity fluctuations and improves cerebral autoregulation in transient ischemic attack patients. J Appl Physiol (1985) 2020; 129:547-557. [DOI: 10.1152/japplphysiol.00160.2020] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
We found dietary nitrate supplementation reduced blood pressure and brain blood flow fluctuations and improved the relationship between blood pressure and brain blood flow in transient ischemic attack patients. Meanwhile, dietary nitrate had no effects on the brain blood vessels’ response to CO2. We attribute the improved brain blood flow stability to the improved myogenic control of blood pressure with dietary nitrate. Our findings indicate that dietary nitrate could be an effective strategy for stabilizing blood pressure and brain blood flow following transient ischemic attack.
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Affiliation(s)
- Jui-Lin Fan
- Wellington Medical Technology Group, Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Terrence O’Donnell
- Wellington Medical Technology Group, Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
| | - Jeremy Lanford
- Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand
| | - Kevin Croft
- School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Eloise Watson
- Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand
| | - Duncan Smyth
- Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand
| | - Henrietta Koch
- School of Biomedical Science, University of Western Australia, Perth, Australia
| | - Lai-Kin Wong
- Department of Neurology, Wellington Regional Hospital, Wellington, New Zealand
| | - Yu-Chieh Tzeng
- Wellington Medical Technology Group, Department of Surgery and Anaesthesia, University of Otago, Wellington, New Zealand
- Centre for Translational Physiology, University of Otago, Wellington, New Zealand
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9
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Abstract
Maternal cardiovascular changes during pregnancy include an expansion of plasma volume, increased cardiac output, decreased peripheral resistance, and increased uteroplacental blood flow. These adaptations facilitate the progressive increase in uteroplacental perfusion that is required for normal fetal growth and development, prevent the development of hypertension, and provide a reserve of blood in anticipation of the significant blood loss associated with parturition. Each woman's genotype and phenotype determine her ability to adapt in response to molecular signals that emanate from the fetoplacental unit. Here, we provide an overview of the major hemodynamic and cardiac changes and then consider regional changes in the splanchnic, renal, cerebral, and uterine circulations in terms of endothelial and vascular smooth muscle cell plasticity. Although consideration of gestational disease is beyond the scope of this review, aberrant signaling and/or maternal responsiveness contribute to the etiology of several common gestational diseases such as preeclampsia, intrauterine growth restriction, and gestational diabetes.
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Affiliation(s)
- George Osol
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405, USA;
| | - Nga Ling Ko
- Department of Obstetrics, Gynecology, and Reproductive Sciences, Larner College of Medicine, University of Vermont, Burlington, Vermont 05405, USA;
| | - Maurizio Mandalà
- Department of Biology, Ecology and Earth Science, University of Calabria, 87036 Arcavacata di Rende (CS), Italy
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10
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Cerebral Blood Flow Regulation in Pregnancy, Hypertension, and Hypertensive Disorders of Pregnancy. Brain Sci 2019; 9:brainsci9090224. [PMID: 31487961 PMCID: PMC6769869 DOI: 10.3390/brainsci9090224] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/26/2019] [Accepted: 09/03/2019] [Indexed: 01/12/2023] Open
Abstract
The regulation of cerebral blood flow (CBF) allows for the metabolic demands of the brain to be met and for normal brain function including cognition (learning and memory). Regulation of CBF ensures relatively constant blood flow to the brain despite changes in systemic blood pressure, protecting the fragile micro-vessels from damage. CBF regulation is altered in pregnancy and is further altered by hypertension and hypertensive disorders of pregnancy including preeclampsia. The mechanisms contributing to changes in CBF in normal pregnancy, hypertension, and preeclampsia have not been fully elucidated. This review summarizes what is known about changes in CBF regulation during pregnancy, hypertension, and preeclampsia.
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11
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Johnson AC, Cipolla MJ. Impaired function of cerebral parenchymal arterioles in experimental preeclampsia. Microvasc Res 2018; 119:64-72. [PMID: 29705580 DOI: 10.1016/j.mvr.2018.04.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 04/20/2018] [Accepted: 04/20/2018] [Indexed: 01/17/2023]
Abstract
Preeclampsia (PE), a dangerous hypertensive complication of pregnancy, is associated with widespread maternal vascular dysfunction. However, the effect of PE on the cerebral vasculature that can lead to stroke and cognitive decline is not well understood. We hypothesized that function of cortical parenchymal arterioles (PAs) would be impaired during PE. Using a high cholesterol diet to induce experimental PE in rats (ePE), we studied the function and structure of isolated and pressurized PAs supplying frontoparietal white matter (WM) tracts and cortex and compared to normal pregnant (Preg) and nonpregnant (Nonpreg) Sprague Dawley rats (n = 8/group). Myogenic reactivity and tone were similar between groups; however, constriction to intermediate-conductance calcium-activated potassium (IK) channel inhibition was diminished and dilation to inward-rectifying K+ (KIR) channel activation was impaired in PAs from ePE rats, suggesting altered ion channel function. Conducted vasodilation was significantly delayed in response to 12 mM KCl, but not 10 μM adenosine, in PAs from ePE rats versus Preg and Nonpreg rats (940 ± 300 ms vs. 70 ± 50 ms and 370 ± 90 ms; p < 0.05). Overall, dysfunction of PAs supplying frontoparietal WM and gray matter was present in ePE. If persistent these changes could potentiate neuronal injury that over time could contribute to WM lesions and early-onset cognitive decline.
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Affiliation(s)
- Abbie C Johnson
- Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA.
| | - Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA; Department of Obstetrics, Gynecology, and Reproductive Sciences, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA; Department of Pharmacology, University of Vermont Larner College of Medicine, Burlington, VT 05405, USA
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12
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Changes in cerebral autoregulation in the second half of pregnancy and compared to non-pregnant controls. Pregnancy Hypertens 2016; 6:380-383. [PMID: 27939486 DOI: 10.1016/j.preghy.2016.08.242] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 07/26/2016] [Accepted: 08/26/2016] [Indexed: 11/23/2022]
Abstract
OBJECTIVE The mechanism by which pregnancy affects the cerebral circulation is unknown, but it has a central role in the development of neurological complications in preeclampsia, which is believed to be related to impaired autoregulation. We evaluated the cerebral autoregulation in the second half of pregnancy, and compared this with a control group of healthy, fertile non-pregnant women. METHODS In a prospective cohort analysis, cerebral blood flow velocity of the middle cerebral artery (determined by transcranial Doppler), blood pressure (noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously collected for 7min. The autoregulation index (ARI) was calculated. ARI values of 0 and 9 indicated absent and perfect autoregulation, respectively. ANOVA and Pearson's correlation coefficient were used, with p<0.05 considered significant. RESULTS A total of 76 pregnant and 18 non-pregnant women were included. The ARI did not change during pregnancy, but pregnant women had a significantly higher ARI than non-pregnant controls (ARI 6.7±0.9 vs. 5.3±1.4, p<0.001). This remained significant after adjusting for EtCO2 (p<0.001). CONCLUSION Cerebral autoregulation functionality is enhanced in the second half of pregnancy, when compared to non-pregnant fertile women, even after controlling for EtCO2. The autoregulation does not change with advancing gestational age.
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13
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Abstract
Cerebral blood flow (CBF) regulation is an indicator of cerebrovascular health increasingly recognized as being influenced by physical activity. Although regular exercise is recommended during healthy pregnancy, the effects of exercise on CBF regulation during this critical period of important blood flow increase and redistribution remain incompletely understood. Moreover, only a few studies have evaluated the effects of human pregnancy on CBF regulation. The present work summarizes current knowledge on CBF regulation in humans at rest and during aerobic exercise in relation to healthy pregnancy. Important gaps in the literature are highlighted, emphasizing the need to conduct well-designed studies assessing cerebrovascular function before, during and after this crucial life period to evaluate the potential cerebrovascular risks and benefits of exercise during pregnancy.
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14
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Johnson AC, Cipolla MJ. The cerebral circulation during pregnancy: adapting to preserve normalcy. Physiology (Bethesda) 2015; 30:139-47. [PMID: 25729059 DOI: 10.1152/physiol.00048.2014] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The adaptation of the brain and cerebral circulation to pregnancy are unique compared with other organs and circulatory systems, ultimately functioning to maintain brain homeostasis. In this review, the effect of pregnancy on critical functions of the cerebral circulation is discussed, including changes occurring at the endothelium and blood-brain barrier, and changes in the structure and function of cerebral arteries and arterioles, hemodynamics, and cerebral blood flow autoregulation.
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Affiliation(s)
- Abbie C Johnson
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont
| | - Marilyn J Cipolla
- Department of Neurological Sciences, University of Vermont College of Medicine, Burlington, Vermont
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15
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Abstract
The cerebrovascular regulation involves highly complex mechanisms to assure that the brain is perfused at all times. These mechanisms depend on all components of the neurovascular units: neurons, glia, and vascular cells. All these cell types can produce nitric oxide (NO), a powerful vasodilator through different NO synthases. Many studies underlined the key role of NO in the maintenance of resting cerebral blood flow (CBF) as well as in the mechanisms that control cerebrovascular tone: autoregulation and neurovascular coupling. However, although the role of NO in the control of CBF has been largely investigated, the complexity of the NO system and the lack of specific NO synthase inhibitors led to still unresolved questions such as the origin of NO and the pathways by which it controls the vascular tone. In this chapter, the role of NO in the regulation of CBF is critically reviewed and discussed in the context of the neurovascular unit and the general principles of cerebrovascular regulation.
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