Topic
Cerebrovascular Physiology
About: Cerebrovascular Physiology is a research topic. Over the lifetime, 38 publications have been published within this topic receiving 1057 citations.
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TL;DR: TCD is an efficient tool to access blood velocities within the cerebral vessels, cerebral autoregulation, cerebrovascular reactivity to CO(2), and neurovascular coupling in both physiological states and in pathological conditions such as stroke and head trauma.
460 citations
TL;DR: Observations indicate that the cerebral vessels of the healthy newborn infant, even the very preterm, respond to physiological stimuli in the same manner as in the mature organism, whereas cerebral blood flow remains constant at minor fluctuations in arterial blood pressure.
Abstract: A knowledge of neonatal cerebrovascular physiology is essential to the understanding of diseases that frequently affect the subsequent development of the newborn brain. Recent observations indicate that the cerebral vessels of the healthy newborn infant, even the very preterm, respond to physiological stimuli in the same manner as in the mature organism. Thus, cerebral blood flow changes with changes in arterial carbon dioxide tension (Paco2), oxygen concentration (Cao2), or glucose concentration, whereas cerebral blood flow remains constant at minor fluctuations in arterial blood pressure. In pathological states, pressure autoregulation may become impaired, and in severe cases the vessels do not react to chemical or metabolic stimuli. These infants are at high risk for developing cerebral lesions, and they may be candidates for new „brain-protecting regimens”.
162 citations
TL;DR: There is a role for novel neuroprotective interventions, many of which are currently under investigation, in the prevention, detection and reversal of secondary neuronal injury in intensive care in acute head injury.
Abstract: The primary role of intensive care in acute head injury lies in the prevention, detection and reversal of secondary neuronal injury. The maintenance of optimal systemic and cerebrovascular physiology can substantially contribute to these aims. There is, however, a role for novel neuroprotective interventions, many of which are currently under investigation.
140 citations
TL;DR: An in-depth description of CBF regulation in response to alterations in PaCO2 is provided, with further consideration of how differences in reactivity of parallel networks can lead to the "steal" phenomenon.
Abstract: Intact, coordinated, and precisely regulated cerebrovascular responses are required for the maintenance of cerebral metabolic homeostasis, adequate perfusion, oxygen delivery, and acid-base balance during deviations from homeostasis. Increases and decreases in the partial pressure of arterial carbon dioxide (PaCO2 ) lead to robust and rapid increases and decreases in cerebral blood flow (CBF). In awake and healthy humans, PaCO2 is the most potent regulator of CBF, and even small fluctuations can result in large changes in CBF. Alterations in the responsiveness of the cerebral vasculature can be detected with carefully controlled stimulus-response paradigms and hold relevance for cerebrovascular risk in steno-occlusive disease. As changes in PaCO2 do not typically occur in isolation, the integrative influence of physiological factors such as intracranial pressure, arterial oxygen content, cerebral perfusion pressure, and sympathetic nervous activity must be considered. Further, age and sex, as well as vascular pathologies are also important to consider. Following a brief summary of key historical events in the development of our understanding of cerebrovascular physiology and an overview of the measurement techniques to index CBF this review provides an in-depth description of CBF regulation in response to alterations in PaCO2 . Cerebrovascular reactivity and regional flow distribution are described, with further consideration of how differences in reactivity of parallel networks can lead to the "steal" phenomenon. Factors that influence cerebrovascular reactivity are discussed and the mechanisms and regulatory pathways mediating the exquisite sensitivity of the cerebral vasculature to changes in PaCO2 are outlined. Finally, topical avenues for future research are proposed. © 2019 American Physiological Society. Compr Physiol 9:1101-1154, 2019.
125 citations
TL;DR: The protocol that is described here is designed to purify brain vessel fragments, whilst maintaining structural integrity, and shows that isolated vessels consist of endothelial cells sealed by tight junctions that are surrounded by a continuous basal lamina.
Abstract: In the brain, most of the vascular system consists of a selective barrier, the blood-brain barrier (BBB) that regulates the exchange of molecules and immune cells between the brain and the blood. Moreover, the huge neuronal metabolic demand requires a moment-to-moment regulation of blood flow. Notably, abnormalities of these regulations are etiological hallmarks of most brain pathologies; including glioblastoma, stroke, edema, epilepsy, degenerative diseases (ex: Parkinson’s disease, Alzheimer’s disease), brain tumors, as well as inflammatory conditions such as multiple sclerosis, meningitis and sepsis-induced brain dysfunctions. Thus, understanding the signaling events modulating the cerebrovascular physiology is a major challenge. Much insight into the cellular and molecular properties of the various cell types that compose the cerebrovascular system can be gained from primary culture or cell sorting from freshly dissociated brain tissue. However, properties such as cell polarity, morphology and intercellular relationships are not maintained in such preparations. The protocol that we describe here is designed to purify brain vessel fragments, whilst maintaining structural integrity. We show that isolated vessels consist of endothelial cells sealed by tight junctions that are surrounded by a continuous basal lamina. Pericytes, smooth muscle cells as well as the perivascular astrocyte endfeet membranes remain attached to the endothelial layer. Finally, we describe how to perform immunostaining experiments on purified brain vessels.
68 citations