Stroke in Pregnancy and Preeclampsia: Effect of Low-Dose Aspirin Treatment on Collateral Flow Velocity and Cerebral Blood Flow Autoregulation During Ischemia in Rats.

Background: Experimental preeclampsia (ePE) has been shown to have worsened outcome from stroke. We investigated the effect of low-dose aspirin, known to prevent preeclampsia, on stroke hemodynamics and outcome, and the association between the vasoconstrictor and vasodilator cyclooxygenase products thromboxane A and prostacyclin.

Methods And Results: Middle cerebral artery occlusion was performed for 3 hours with 1 hour of reperfusion in normal pregnant rats on day 20 of gestation and compared with ePE treated with vehicle or low-dose aspirin (1.

Thrombin in Pregnancy and Preeclampsia: Expression, Localization, and Vasoactivity in Brain and Microvessels From Rats.

Thrombin is a coagulation factor increased in pregnancy and further increased in preeclampsia (PE), a hypertensive disorder. Thrombin is also expressed in the brain and may have a nonhemostatic role. We characterized thrombin expression and vasoactivity in brain cerebral parenchymal arterioles (PAs) in rat models of pregnancy and PE.

Chronic hypertension alters the relationship between collateral blood flow cortical cerebral blood flow, and brain tissue oxygenation.

This study measured the relationship between pial collateral (leptomeningeal anastomoses, LMA) flow, intraparenchymal cortical cerebral blood flow (cCBF) and brain tissue oxygenation (btO) during acute ischemic stroke to investigate how pial flow translates to downstream cCBF and btO and examined how this relationship is altered in hypertension. Proximal transient middle cerebral artery occlusion (tMCAO) was performed in male Wistar (n = 8/group) and Spontaneously Hypertensive Rats (SHR, n = 8/group). A combination laser Doppler-oxygen probe was placed within the expected cortical peri-infarct in addition to a surface laser doppler probe which measured LMA flow.

Functional role of myosin-binding protein H in thick filaments of developing vertebrate fast-twitch skeletal muscle.

Myosin-binding protein H (MyBP-H) is a component of the vertebrate skeletal muscle sarcomere with sequence and domain homology to myosin-binding protein C (MyBP-C). Whereas skeletal muscle isoforms of MyBP-C (fMyBP-C, sMyBP-C) modulate muscle contractility via interactions with actin thin filaments and myosin motors within the muscle sarcomere "C-zone," MyBP-H has no known function. This is in part due to MyBP-H having limited expression in adult fast-twitch muscle and no known involvement in muscle disease.

Dilation of Pregnant Rat Uterine Arteries with Phenols from Extra Virgin Olive Oil Is Endothelium-Dependent and Involves Calcium and Potassium Channels.

During pregnancy, uterine vasculature undergoes significant circumferential growth to increase uterine blood flow, vital for the growing feto-placental unit. However, this process is often compromised in conditions like maternal high blood pressure, particularly in preeclampsia (PE), leading to fetal growth impairment. Currently, there is no cure for PE, partly due to the adverse effects of anti-hypertensive drugs on maternal and fetal health.

The impact of collateral therapeutics on stroke hemodynamics in normotensive and hypertensive rats: a step toward translation.

Introduction: Stroke interventions that increase collateral flow have the potential to salvage penumbral tissue and increase the number of patients eligible for reperfusion therapy. We compared the efficacy of two different collateral therapeutics during transient middle cerebral artery occlusion (tMCAO) in normotensive and hypertensive rats.

Methods: The change in collateral and core perfusion was measured using dual laser Doppler in response to either a pressor agent (phenylephrine, 10 mg/kg iv or vehicle) or a collateral vasodilator (TM5441, 5 mg/kg iv or vehicle) given 30 min into tMCAO in male Wistar and spontaneously hypertensive rats (SHRs).

Differential effect of gold nanoparticles on cerebrovascular function and biomechanical properties.

Human stroke serum (HSS) has been shown to impair cerebrovascular function, likely by factors released into the circulation after ischemia. 20 nm gold nanoparticles (GNPs) have demonstrated anti-inflammatory properties, with evidence that they decrease pathologic markers of ischemic severity. Whether GNPs affect cerebrovascular function, and potentially protect against the damaging effects of HSS on the cerebral circulation remains unclear.

Worsened Stroke Outcome in a Model of Preeclampsia is Associated With Poor Collateral Flow and Oxidative Stress.

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+MgSO) compared to normal late-pregnant and nonpregnant rats.

Methods: Transient middle cerebral artery occlusion was used to induce focal stroke for either 1.

Retrospective study of medical student scholarship and career trajectory following a mentored preclinical cardiovascular summer research fellowship.

Objectives: Developing a preclinical training infrastructure for cardiovascular clinician-scientists is an academic workforce priority. The Cardiovascular Research Institute of Vermont developed a cardiovascular summer research fellowship (SRF), wherein medical student awardees were selected by merit-based application and completed mentored research between the first and second years. We aimed to study the impact of the SRF on medical student scholarship and career planning.

Cerebral Blood Flow Autoregulation in Offspring From Experimentally Preeclamptic Rats and the Effect of Age.

Preeclampsia is a hypertensive disorder of pregnancy that causes significant, long term cardiovascular effects for both the mother and offspring. A previous study demonstrated that middle cerebral arteries in offspring from an experimental rat model of preeclampsia were smaller, stiffer, and did not enlarge over the course of maturation, suggesting potential hemodynamic alterations in these offspring. Here we investigated the effect of experimental preeclampsia on cerebral blood flow autoregulation in juvenile and adult offspring that were born from normal pregnant or experimentally preeclamptic rats.

Experimental Preeclampsia Causes Long-Lasting Hippocampal Vascular Dysfunction and Memory Impairment.

Preeclampsia (PE) is a hypertensive disorder of pregnancy that is associated with memory impairment, cognitive decline and brain atrophy later in life in women at ages as young as early-to-mid 40 s. PE increases the risk of vascular dementia three-fold, however, long-lasting effects of PE on the vasculature of vulnerable brain regions involved in memory and cognition, such as the hippocampus, remain unknown. Here, we used a rat model of experimental PE (ePE) induced by maintaining rats on a 2% cholesterol diet beginning on day 7 of gestation to investigate hippocampal function later in life.

Therapeutic Induction of Collateral Flow.

Therapeutic induction of collateral flow as a means to salvage tissue and improve outcome from acute ischemic stroke is a promising approach in the era in which endovascular therapy is no longer time-dependent but collateral-dependent. The importance of collateral flow enhancement as a therapeutic for acute ischemic stroke extends beyond those patients with large amounts of salvageable tissue. It also has the potential to extend the time window for reperfusion therapies in patients who are ineligible for endovascular thrombectomy.

Treatment with apocynin selectively restores hippocampal arteriole function and seizure-induced hyperemia in a model of preeclampsia.

Preeclampsia (PE) is a hypertensive disorder of pregnancy associated with neurovascular dysfunction, cognitive impairment and increased seizure susceptibility. Here, we sought to determine if treatment of experimental PE (ePE) rats with apocynin could prevent hippocampal arteriolar (HA) dysfunction and impaired seizure-induced hyperemia within the hippocampus, a brain region central to cognition and seizure generation. Isolated and pressurized HAs from Sprague Dawley rats that were normal pregnant (Preg; n = 8), ePE (n = 8) or ePE treated with apocynin for 2 weeks of gestation (ePE + apo; n = 8) were compared.

Aging-Related Structural and Functional Changes in Cerebral Arteries: Caloric Restriction (CR) Intervention.

Cerebral arteries play a crucial role in the regulation of blood flow to the brain to satisfy the demand of oxygen and glucose for proper function of the organ. Physiological cerebral blood flow (CBF) is maintained within a normal range in response to changes in blood pressure a mechanism named Cerebral Blood Flow Auto Regulation (CBFAR). Structure and function of cerebral arteries have an important impact on CBFAR.

Mechanisms of Flow-Mediated Dilation of Pial Collaterals and the Effect of Hypertension.

Leptomeningeal anastomoses are small distal anastomotic vessels also known as pial collaterals in the brain. These vessels redirect blood flow during an occlusion and are important for stroke treatment and outcome. Pial collaterals have unique hemodynamic forces and experience significantly increased luminal flow and shear stress after the onset of ischemic stroke.

Thomas Willis Lecture: Targeting Brain Arterioles for Acute Stroke Treatment.

Cerebral infarction or ischemic death of brain tissue, most notably neurons, is a primary response to vascular occlusion that if minimized leads to better stroke outcome. However, many cell types are affected in the brain during ischemia and reperfusion, including vascular cells of the cerebral circulation. Importantly, the structure and function of all brain vascular segments are major determinants of the depth of ischemia during the occlusion, the extent of collateral flow (and therefore amount of potentially salvageable tissue) and the degree of reperfusion.

Vascular Biology.

The article summarizes recent studies investigating mechanisms of collateral flow variability in stroke, and the role of pericytes in cerebral microcirculation and stroke.

Abnormal development of cerebral arteries and veins in offspring of experimentally preeclamptic rats: Potential role in perinatal stroke.

Preeclampsia, a hypertensive disorder of pregnancy, complicates up to 10 % of all pregnancies and increases the risk for perinatal stroke in offspring. The mechanism of this increase is unknown, but may involve vascular dysfunction. The goal of this study was to evaluate the effect of experimental preeclampsia (ePE) on cerebrovascular function in offspring to eludciate a possible mechanism for this association.