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Cerebrovascular reactivity

Changhwan Seo, Seonghun Kim, Misol Lee, Min-Uk Cha, Hyoungnae Kim, Seohyun Park, Hae-Ryong Yun, Jong Hyun Jhee, Youn Kyung Kee, Seung Hyeok Han, Tae-Hyun Yoo, Shin-Wook Kang, Jung Tak Park
OBJECTIVE: Patients with diabetic nephropathy (DMN) have an increased risk of cardiovascular disease (CVD). However, strategies to reduce this risk are limited. Thyroid hormone replacement therapy (THRT) in patients with hypothyroidism has been shown to reduce several surrogate markers of CVD. Therefore, we performed a study to determine if THRT would reduce CVD risk in patients with subclinical hypothyroidism (SCH) and DMN. METHODS: This was a retrospective, nonrandomized study of patients with type 2 diabetes, DMN, and SCH...
March 2018: Endocrine Practice
Jungyun Hwang, Kiyoung Kim, R Matthew Brothers, Darla M Castelli, F Gonzalez-Lima
Studies of the effects of physical activity on cognition suggest that aerobic fitness can improve cognitive abilities. However, the physiological mechanisms for the cognitive benefit of aerobic fitness are less well understood. We examined the association between aerobic fitness and cerebrovascular function with neurocognitive functions in healthy, young adults. Participants aged 18-29 years underwent measurements of cerebral vasomotor reactivity (CVMR) in response to rebreathing-induced hypercapnia, maximal oxygen uptake (VO2 max) during cycle ergometry to voluntary exhaustion, and simple- and complex-neurocognitive assessments at rest...
March 14, 2018: Experimental Brain Research. Experimentelle Hirnforschung. Expérimentation Cérébrale
Arkadiusz Szarmach, Mariusz Kaszubowski, Agnieszka Sabisz, Andrzej F Frydrychowski, Grzegorz Halena, Maciej Piskunowicz, Jarosław Dzierzanowski, Michał Studniarek, Edyta Szurowska, Pawel J Winklewski
The aim of this study was to assess regional perfusion at baseline and regional cerebrovascular resistance (CVR) to delayed acetazolamide challenge in subjects with chronic carotid artery stenosis. Sixteen patients (ten males) aged 70.94±7.71 with carotid artery stenosis ≥ 90% on the ipsilateral side and ≤ 50% on the contralateral side were enrolled into the study. In all patients, two computed tomography perfusion examinations were carried out; the first was performed before acetazolamide administration and the second 60 minutes after injection...
March 12, 2018: Acta Biochimica Polonica
Jennifer M Watchmaker, Blaise deB Frederick, Matthew R Fusco, Larry T Davis, Meher R Juttukonda, Sarah K Lants, Howard S Kirshner, Manus J Donahue
BACKGROUND: Surgical revascularization is often performed in patients with moyamoya, however routine tools for efficacy evaluation are underdeveloped. The gold standard is digital subtraction angiography (DSA); however, DSA requires ionizing radiation and procedural risk, and therefore is suboptimal for routine surveillance of parenchymal health. OBJECTIVE: To determine whether parenchymal vascular compliance measures, obtained noninvasively using magnetic resonance imaging (MRI), provide surrogates to revascularization success by comparing measures with DSA before and after surgical revascularization...
March 8, 2018: Neurosurgery
Kouichi Misaki, Naoyuki Uchiyama, Anri Inaki, Seigo Kinuya, Iku Nambu, Tomoya Kamide, Masanao Mohri, Yasuhiko Hayashi, Mitsutoshi Nakada
BACKGROUND AND PURPOSE: Hemodynamic impairments are considered risk factors of cerebral hyperperfusion after carotid artery stenting (CAS); measurement by SPECT using a subjective ROI method lacks consistency and reproducibility. MATERIALS AND METHODS: The present study compared objective perfusion analysis (stereotactic extraction estimation [SEE] method) with the ROI method for preoperative SPECT to predict the hyperperfusion phenomenon (HPP) after CAS. Preoperative resting asymmetry index (CBF ratio from the affected to unaffected hemisphere) and cerebrovascular reactivity (CVR) to acetazolamide were measured by N-isopropyl-p-[123 I]-iodoamphetamine SPECT using the SEE and ROI method in 84 patients...
March 7, 2018: Journal of Neuroradiology. Journal de Neuroradiologie
Tatyana Merkulova-Rainon, Chris S Mantsounga, Dong Broquères-You, Cristina Pinto, José Vilar, Diana Cifuentes, Philippe Bonnin, Nathalie Kubis, Daniel Henrion, Jean-Sébastien Silvestre, Bernard I Lévy
The pathophysiology of sporadic Alzheimer's disease (AD) remains uncertain. Along with brain amyloid-β (Aβ) deposits and neurofibrillary tangles, cerebrovascular dysfunction is increasingly recognized as fundamental to the pathogenesis of AD. Using an experimental model of limb ischemia in transgenic APPPS1 mice, a model of AD (AD mice), we showed that microvascular impairment also extends to the peripheral vasculature in AD. At D70 following femoral ligation, we evidenced a significant decrease in cutaneous blood flow (- 29%, P < 0...
March 7, 2018: Angiogenesis
Baraa K Al-Khazraji, Leena N Shoemaker, Joseph S Gati, Trevor Szekeres, J Kevin Shoemaker
The larger intracranial conduit vessels contribute to the total cerebral vascular resistance, and understanding their vasoreactivity to physiological stimuli is required when attempting to understand regional brain perfusion. Reactivity of the larger cerebral conduit arteries remains understudied due to a need for improved imaging methods to simultaneously assess these vessels in a single stimulus. We characterized reactivity of basal intracranial conduit arteries (basilar, right and left posterior, middle and anterior cerebral arteries) and the right and left internal carotid arteries, to manipulations in end-tidal CO2 (PetCO2 )...
January 1, 2018: Journal of Cerebral Blood Flow and Metabolism
Brice Ongali, Nektaria Nicolakakis, Xin-Kang Tong, Clotilde Lecrux, Hans Imboden, Edith Eh Hamel
Transgenic mice constitutively overexpressing the cytokine transforming growth factor-β1 (TGF-β1) (TGF mice) display cerebrovascular alterations as seen in Alzheimer's disease (AD) and vascular cognitive impairment and dementia (VCID), but no or only subtle cognitive deficits. TGF-β1 may exert part of its deleterious effects through interactions with angiotensin II (AngII) type 1 receptor (AT1R) signaling pathways. We test such interactions in the brain and cerebral vessels of TGF mice by measuring cerebrovascular reactivity, levels of protein markers of vascular fibrosis, nitric oxide synthase activity, astrogliosis and mnemonic performance in mice treated (6 months) with the AT1R blocker, losartan (10 mg/kg/day), or the angiotensin converting enzyme inhibitor enalapril (ACEi,3 mg/kg/day)...
March 5, 2018: Canadian Journal of Physiology and Pharmacology
Craig P Allen, Kicheon Park, Ang Li, Nora D Volkow, George F Koob, Yingtian Pan, Xiu-Ti Hu, Congwu Du
Cocaine addiction is associated with dysfunction of the prefrontal cortex (PFC), which facilitates relapse and compulsive drug taking. To assess if cocaine's effects on both neuronal and vascular activity contribute to PFC dysfunction, we used optical coherence tomography and multi-wavelength laser speckle to measure vascularization and hemodynamics and used GCaMP6f to monitor intracellular Ca2+ levels ([Ca2+ ]in ) as a marker of neuronal activity. Rats were given short (1 hour; ShA) or long (6 hours; LgA) access cocaine self-administration...
March 5, 2018: Addiction Biology
Denis E Bragin, Gloria L Statom, Edwin M Nemoto
OBJECTIVE: In previous work we showed that high intracranial pressure (ICP) in the rat brain induces a transition from capillary (CAP) to pathological microvascular shunt (MVS) flow, resulting in brain hypoxia, edema, and blood-brain barrier (BBB) damage. This transition was correlated with a loss of cerebral blood flow (CBF) autoregulation undetected by static autoregulatory curves but identified by induced dynamic ICP (iPRx) and cerebrovascular (iCVRx) reactivity. We hypothesized that loss of CBF autoregulation as correlated with MVS flow would be identified by iPRx and iCVRx in traumatic brain injury (TBI) with elevated ICP...
2018: Acta Neurochirurgica. Supplement
Konstantin Hockel, Martin U Schuhmann
OBJECTIVE: A drawback in the use of an external ventricular drain (EVD) originates in the fact that draining cerebrospinal fluid (CSF) (open system) and intracranial pressure (ICP) monitoring can be done at the same time but is considered to be unreliable regarding the ICP trace. Furthermore, with the more widespread use of autoregulation monitoring using blood pressure and ICP signals, the question arises of whether an ICP signal from an open EVD can be used for this purpose. Using an EVD system with an integrated parenchymal ICP probe we compared the different traces of an ICP signal and their derived parameters under opened and closed CSF drainage...
2018: Acta Neurochirurgica. Supplement
Samuel Patrick Klein, Bart Depreitere
INTRODUCTION:  Episodes of raised intracranial pressure (ICP) after traumatic brain injury (TBI) are responsible for the majority of secondary brain injury events and thereby strongly affect long-term outcome. However, not all patients with major episodes of raised ICP suffer a poor outcome. The aim of the current analysis was to identify variables contributing to good outcome in patients suffering episodes of high ICP. METHODS:  Retrospective analysis of 20 severe TBI patients admitted to the University Hospitals Leuven between 2010 and 2014...
2018: Acta Neurochirurgica. Supplement
Zhenyan Wang, Li Liu, Yin-Zhong Shen, Ren-Fang Zhang, Tang-Kai Qi, Yang Tang, Wei Song, Jun Chen, Hongzhou Lu
Neurosyphilis (NS) is an important component of central nervous system diseases among HIV-infected patients. However, its characteristics are not very clear. A retrospective analysis of clinical and laboratory findings was performed in 92 NS patients with HIV infection from a tertiary hospital in Shanghai, China. The patients had a median age of 38 years and a median CD4 count of 198 cells/μL. In all, 44.6% (41/92) were diagnosed as asymptomatic NS (ANS), 23.9% (22/92) as syphilitic meningitis, 17.4% (16/92) as cerebrovascular NS, and 14...
March 2018: Medicine (Baltimore)
Laura B Ponsaing, Ulrich Lindberg, Egill Rostrup, Helle K Iversen, Henrik B W Larsson, Poul Jennum
OBJECTIVE: Obstructive sleep apnea (OSA) is an independent risk factor for stroke. Little is known about the cerebrovascular hemodynamic changes during apnea. Hypercapnia occurs in apneas and hypopneas, and a reduced cerebral vasodilatory response to CO2 could compromise the cerebral blood flow (CBF). Therefore, we aimed to evaluate whether the apnea-hypopnea index (AHI) affected the cerebrovascular response to CO2 . METHODS: A total of 11 patients with OSA were compared to 16 controls...
March 2018: Sleep Medicine
Ahmed M Hashad, Maria Sancho, Suzanne E Brett, Donald G Welsh
Vascular T-type Ca2+ channels (CaV 3.1 and CaV 3.2) play a key role in arterial tone development. This study investigated whether this conductance is a regulatory target of angiotensin II (Ang II), a vasoactive peptide that circulates and which is locally produced within the arterial wall. Patch clamp electrophysiology performed on rat cerebral arterial smooth muscle cells reveals that Ang II (100 nM) inhibited T-type currents through AT1 receptor activation. Blocking protein kinase C failed to eliminate channel suppression, a finding consistent with unique signaling proteins enabling this response...
February 22, 2018: Scientific Reports
Alberto Merola, Michael A Germuska, Kevin Murphy, Richard G Wise
As energy metabolism in the brain is largely oxidative, the measurement of cerebral metabolic rate of oxygen consumption (CMRO 2 ) is a desirable biomarker for quantifying brain activity and tissue viability. Currently, PET techniques based on oxygen isotopes are the gold standard for obtaining whole brain CMRO 2 maps. Among MRI techniques that have been developed as an alternative are dual calibrated fMRI (dcFMRI) methods, which exploit simultaneous measurements of BOLD and ASL signals during a hypercapnic-hyperoxic experiment to modulate brain blood flow and oxygenation...
February 14, 2018: NeuroImage
Powell P W Chu, Ali M Golestani, Jonathan B Kwinta, Yasha B Khatamian, J Jean Chen
The blood-oxygenation level dependent (BOLD) functional magnetic resonance imaging (fMRI) signal is commonly used to assess functional connectivity across brain regions, particularly in the resting state (rs-fMRI). However, the BOLD fMRI signal is not merely a representation of neural activity, but a combination of neural activity and vascular response. These aspects of the BOLD signal are easily influenced by systemic physiology, potentially biasing BOLD-based functional connectivity measurements. In this work, we focus on the following physiological modulators of the BOLD signal: cerebral blood flow (CBF), venous blood oxygenation, and cerebrovascular reactivity (CVR)...
February 13, 2018: NeuroImage
Andrea Iorio, Dorina Ylli, Renato Polimanti, Fabiana Picconi, Paola Maggio, Davide Francomano, Antonio Aversa, Dario Manfellotto, Maria Fuciarelli, Simona Frontoni
AIMS: An increased rate of cerebrovascular complications in patients with metabolic syndrome (MetS) has been reported. Previous studies demonstrated an association between glycemic variability (GV) and cerebrovascular reactivity (CRV) in MetS, thus suggesting a putative role of GV on cerebrovascular events. Although the pathophysiological mechanism linking GV to damage is still to be elucidated, evidence suggests oxidative stress plays a crucial role. Since functional variants in glutathione S-transferases (GST) genes modulate the cellular detoxification processes, the aim of this study was to elucidate the involvement of GSTs in MetS and investigating the correlation with GV, arterial stiffness, and sympatho-vagal (SV) balance...
February 13, 2018: Diabetes Research and Clinical Practice
Christiaan Hendrik Bas van Niftrik, Marco Piccirelli, Oliver Bozinov, Nicolai Maldaner, Catherine Strittmatter, Athina Pangalu, Antonios Valavanis, Luca Regli, Jorn Fierstra
Neurovascular coupling describes the cascade between neuronal activity and subsequent Blood-Oxygenation-Level-Dependent (BOLD) signal increase. Based on this premise, the correlation of this BOLD signal increase with a particular task, such as finger-tapping, is used to map neuronal activation. This signal increase may be dampened in brain areas exhibiting impaired cerebrovascular reactivity (BOLD-CVR), leading to false negative activation. Blood-oxygenation-level-dependent (BOLD) cerebrovascular reactivity (CVR) has also been used to optimize task evoked BOLD signal changes...
February 13, 2018: Magnetic Resonance Imaging
Yang Li, Abdul Qadir Nawabi, Yi Feng, Genshan Ma, Jiayi Tong, Chengxing Shen, Naifeng Liu
Objective The clinical implication of coronary tortuosity is unclear. The present study was conducted to determine the relationships between coronary tortuosity and the high-sensitivity C-reactive protein (hs-CRP) concentration and between coronary tortuosity and cerebrovascular accident in hypertensive patients without coronary artery disease. Methods In total, 236 patients with normal coronary angiography findings were categorized into 3 different groups: control participants (n = 58), who had neither hypertension nor coronary tortuosity; patients with hypertension but no coronary tortuosity (H-NCT group, n = 93); and patients with both hypertension and coronary tortuosity (H-CT group, n = 85)...
January 1, 2018: Journal of International Medical Research
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