bluuebunny/crossref_metadata_2025_split huggingface dataset:
Decreased Glucocorticoid Exposure In Utero Alters Cerebral Artery Development And Reduces Ischemia‐Induced Vascular Injury In The Neonatal Rat Brain
Authors: Durrant Lara , Jackson Patsy Naomi , Carreon Desirelys , Doan Coleen , Pearce William 
Published: November 2023

INTRODUCTIONAbundant evidence suggests an important role of glucocorticoids (GC) in cerebral injury produced by ischemia, particularly in neonates. The majority of this evidence is focused on the role of GC in neuronal, glial, and endothelial acute responses to injury. In addition to involvement in acute responses, however, GC also play a critical role in cerebrovascular growth and development in utero. Elevation of maternal GC during pregnancy can dramatically alter cerebrovascular structure‐function relations in offspring. The present study examines the hypothesis that depressed glucocorticoid exposure in utero also programs the developing cerebrovasculature, thereby altering the postnatal cerebrovascular responses to ischemia.METHODSThe experimental design included four groups: 1) Sham Operated; 2) Ischemia; 3) Sham + Metyrapone; and 4) Ischemia + Metyrapone. Metyrapone (MET), an inhibitor of the enzyme 11‐β hydroxylase that synthesizes corticosterone, was administered in the drinking water at 0.5 mg/ml from day 11 of gestation until birth. At postnatal day 9, rat pups were anesthetized with isoflurane and underwent unilateral carotid ligation, were allowed 24 hours to recover, and then were exposed for 90 minutes to 8% hypoxia. All pups were sacrificed at postnatal days 11–12 after which middle cerebral arteries were harvested for myography and confocal analysis.RESULTSWhen compared to Sham arteries, ischemia increased passive diameters by up to 25 μm (15%, P<0.05) and MET reduced this effect to 7 μm (4%, NS). Calculations of incremental compliance at 50 mmHg in Ischemic arteries revealed a decrease in compliance by −0.04 μm/mmHg (−43%, P<0.05), and these changes were ablated after MET and averaged 0.01 μm/mmHg (12 %, NS). Ischemia increased pressure‐induced myogenic changes in Ischemic artery diameter at 40 mmHg by up to 16 μm (62 %, P<0.05); treatment with MET reduced this effect to only 2 μm (6 %, NS). Ischemia increased the diameter changes induced by potassium at 60 mm Hg by 25 μm (73%, P<0.05), and this effect at 60 mm Hg was converted by MET to a decrease of −11 μm (−23%, P<0.05). Ischemia elevated the potassium‐induced increases in cytosolic calcium at 80 mm Hg by 25% (P<0.05) and MET reduced this effect to −11% (P<0.05). Finally, ischemia increased myofilament calcium sensitivity at 20 mm Hg by 49% (P<0.05), but after MET this change averaged −5% (NS).CONCLUSIONSThese results support the hypothesis that glucocorticoids play a critical role during cerebrovascular development. In addition, this data demonstrates that decreased glucocorticoid exposure during pregnancy may decrease the vulnerability of the fetal vasculature to postnatal ischemic injury.Support or Funding InformationThese studies were supported by an NIH Program Project grant from NINDS (NS082184) and an NIH R01 grant also from NINDS (NS076945).
Progressive Loss of Cerebrovascular Reactivity and Nitric Oxide Bioavailability with Ischemic Stroke in Obese Zucker Rats
Authors: Brooks Steven D , Branyan Kayla , DeVallance Evan , Asano Shinichi , Hu Hang , Ren Xuefang , Rottgen Trey , Frisbee Jefferson C , Chantler Paul D 
Published: November 2023

Ischemic stroke occurs when occlusion of a cerebral blood vessel leads to hypoperfusion, ischemia, and infarction of neuronal tissue. In the immediate aftermath of a stroke, maintenance of cerebral blood flow to penumbra is essential to help recover damaged neurons and protect surrounding neurons from insult, and throughout the post‐stroke recovery process, adequate blood flow is necessary to promote recovery and rehabilitation. As such, pre‐existing and stroke‐induced impairments in cerebrovascular reactivity may lead to larger infarcts and worsened long term recovery. The purpose of this study was to evaluate vascular reactivity at 24 hours and 15 days post‐stroke, in the ipsilateral and contralateral hemispheres of rodents with and without comorbid metabolic syndrome. Strokes were induced for 1 hour by transient middle cerebral artery occlusion (tMCAO) in 17 week old lean and obese Zucker rats (LZR, OZR). At either 24 hours post‐occlusion, or 15 days post‐stroke, animals were sacrificed and the ipsilateral (IL) and contralateral (CL) MCAs were removed and cannulated in an ex vivo microvessel preparation. MCA reactivity was assessed in response to acetylcholine. Aortic ring segments were analyzed for nitric oxide (NO) production by DAF assay, and infarct size was measured by TTC stain. In LZR, both IL and CL MCA reactivity at 24 hr. was severely impaired compared to non‐stroke control (over 50% reduction). At 15 days, reactivity decreased another 20% in IL MCA, but remained stable in CL‐MCA. LZR NO bioavailability at 24 hr. was reduced 35% compared to non‐stroke control, which remained constant at 15 days. In OZR, the vascular impairments were more pronounced at 24 hr, and worsened significantly at 15 days. At 24 hr, IL‐MCA reactivity was reduced 80% compared to control, while CL‐MCA was reduced 60%. By 15 days, IL‐MCA reactivity was completely ablated, and CL‐MCA reactivity had decreased another 35%. NO bioavailability for OZR at 24 hr was comparable to LZR stroke, but by 15 days had fallen another 50%. Rates of stroke mortality and infarct size were higher for OZR at both time points as well. These results suggests that ischemic stroke causes severe attenuation of NO bioavailability and cerebrovascular reactivity in both the IL and CL hemispheres of OZR at 24 hrs post‐stroke, with further loss of both at 15 days. While stroke lead to decreased reactivity and NO bioavailability in LZR, degree of impairment was less severe, and remained stable over time. Therefore, the comorbid presence of metabolic syndrome in OZR may increase stroke severity and drive progressive decline of cerebrovascular reactivity following ischemic stroke.Support or Funding InformationAmerican Heart Association Predoctoral Fellowship,NIH COBRE grant
Effect of focal cerebral ischemia on BKCa and TRPV4 in rat middle cerebral artery
Authors: Murphy Timothy V , Nguyen Hong L , Grayson T Hilton , Jones Nicole M , Sandow Shaun L 
Published: November 2023

Large‐conductance Ca2+‐sensitive K+ channels (BKCa) are prime regulators of vascular smooth muscle cell membrane potential and contraction and may be coupled to transient receptor potential vanillioid‐4 (TRPV4) channels. This study examined the expression and function of BKCa and TRPV4 in rat middle‐cerebral arteries (MCA) in stroke. Male Sprague‐Dawley rats were subject to focal cerebral ischemic stroke by localized bolus injection of endothelin‐1 (120 pmol). Controls received saline (0.9%). Five days later, animals were euthanized and the MCAs removed. Immunofluorescence studies showed increased BKCa expression (α‐ and β1‐subunits) in the smooth muscle cells of the arteries from rats with stroke. BKCa was also expressed in the endothelium of MCA from stroke rats, in contrast with arteries from controls. TRPV4 was expressed in both endothelial and smooth muscle cells of the MCA, and expression in both cell types was increased in arteries from stroke rats. Pressurized (80 mmHg) arteries developed myogenic tone, the degree of myogenic tone was not different between arteries from control and stroke rats. The BKCa blocker iberiotoxin (0.1 μM) constricted arteries from stroke rats to greater extent than control MCA. The TRPV4 activator GSK1016790A (GSK) caused concentration‐dependent dilation of MCAs from control and stroke rats; there was no effect of stroke on responses to GSK. In both control and stroke rats, MCA dilation induced by GSK was inhibited by the TRPV4 blocker HC‐067047 (0.3 μM) but not by iberiotoxin. These studies suggest increased BKCa expression and activity contribute to modulation of MCA tone post‐stroke. TRPV4 do not induce dilation of rat MCA through activation of BKCa.Support or Funding InformationThis work was supported by the Brain Foundation.
Heterogeneous Impact of ROCK2 on Carotid and Cerebrovascular Function
Authors: De Silva T. Michael , Kinzenbaw Dale , Modrick Mary L , Reinhardt Lindsey D. , Faraci Frank 
Published: November 2023

Rho kinase (ROCK) is a serine‐threonine kinase that has been implicated in numerous physiological and pathophysiological processes, including regulation of vascular function. Two isoforms of ROCK (1 and 2) have been identified, and both are expressed in vascular cells. Due to a lack of isoform selective inhibitors or relevant genetic models, the role of individual ROCK isoforms in regulating vascular function is not well understood. In the present study, we examined the importance of ROCK2 in relation to vessel function. We used several approaches and models. First, overnight incubation of carotid arteries from C57Bl6/J mice with the direct RhoA activator CN‐03 or angiotensin II (Ang II) impaired endothelium‐dependent, nitric oxide (NO)‐induced relaxation. Endothelium‐independent dilation was not impaired by these treatments. CN‐03‐ and Ang II‐induced endothelial dysfunction was prevented by Y‐27632 (an inhibitor of both ROCK isoforms) or the selective ROCK2 inhibitor SLX‐2119. In fresh untreated vessels (no incubation), SLX‐2119 had little effect on contraction of carotid arteries to U46619, phenylephrine, serotonin or vasopressin. Second, in a resistance vessel (basilar arteries), SLX‐2119 inhibited constriction to Ang II by almost 90% without significantly affecting constriction to KCl or serotonin. Third, ROCK has been identified as an important mediator of myogenic tone. In isolated pressurized brain parenchymal arterioles (baseline diameter = 17±2 μm), SLX‐2119 inhibited myogenic tone in a concentration‐dependent manner. Lastly, SLX‐2119 treatment dilated small pial arterioles in vivo, an effect that was augmented by inhibition of NO synthase. Our findings suggest that ROCK2 has major, but heterogeneous effects on vascular tone. ROCK2 plays a prominent role in regulating endothelial function and select vasoconstrictor responses in resistance vessels (myogenic tone and constriction to Ang II). In contrast, ROCK2 appears to play a much smaller role in vasoconstriction to several other receptor‐mediated agonists. Collectively, these data support the concept that aberrant ROCK2 signaling may be a key contributor to select aspects of large and small vessel disease.Support or Funding InformationSupported by the NIH (HL‐62984, HL‐113863), the Department of Veteran's Affair's (BX001399), the Fondation Leducq, and the NHMRC (1053786).
Detection of TRPV4 channel current‐like activity in Fawn Hooded Hypertensive (FHH) rat cerebral arterial muscle
Authors: Gebremedhin Debebe , Harder David Rae 
Published: November 2023

The FHH rat strain is associated impaired pressure‐dependent myogenic tone and exaggerated cerebral arterial muscle KCa channel current opening. In the present study we examined if the FHH rat cerebral arterial muscle cells exhibit TRPV4 channel current‐like activity. Western blot analysis and RT‐PCR revealed expression of protein and transcript for TRPV4 channel in cerebral arteries of FHH rat strain. Immunostaining using the TRPV4 channel antibody detected presence of TRPV4 channel protein in freshly isolated FHH rat cerebral arterial myocytes. Patch clamp recording of single‐channel current activity in FHH rat cerebral arterial myocytes identified presence of a non‐selective cation channel current with unitary conductances of ~96 pS and ~84.6 pS at depolarizing and hyperpolarizing potentials, respectively, that were sensitive to inhibition by the TRPV4 channel inhibitor RT‐1734 (5 μM) or HC 067074 (0.2 μM) and activated by the potent TRPV4 channel agonist GSK‐101690A (100 nM). These findings indicate that the FHH rat cerebral arterial myocytes appear to express TRPV4 channel current‐like activity that could have relevance for the regulation of calcium movement and calcium‐dependent mechanisms in these cells.Support or Funding InformationThis work is supported by grants from NIH (R01 NIH/NHLBI, HL033833 and HL105997)
Steady‐state Changes in Cerebral Blood Flow between a Sitting and Standing Position Across the Menstrual Cycle
Authors: Favre Michelle , Reyes Levy , Fox Apollonia , Serrador Jorge 
Published: November 2023

The purpose was to determine if steady‐state changes in cerebral blood flow between a sitting and standing position are affected across the menstrual cycle in healthy women with naturally cycling hormones (NOC) compared to women on combined oral contraceptives (OC). Eleven (6 NOC and 5 OC) healthy, women (mean age 25.3 years) were tested during menstruation (M), the late follicular phase (LF), and the mid‐luteal phase (ML). All participants performed sit‐to‐stand maneuvers on each visit while measuring beat‐by‐beat blood pressure, heart rate, end‐tidal CO2, and transcranial Doppler ultrasonography of the anterior and middle cerebral arteries. In addition, five of the women (3NOC, 2 OC) underwent ultrasonography of the internal carotid artery in the sitting position to measure global cerebral blood flow. Results indicate a significant effect (p= 0.02) of oral contraceptives on mean arterial pressure(MAP) in the sitting position (NOC: 74.4 ± 4.4 vs OC: 92.4 ± 4.8 mmHg), but no effect of menstrual cycle phase. Despite significant differences in baseline MAP, there was no difference in the ability to maintain MAP at baseline levels when standing. In contrast, changes in cerebral flow velocity (CFV) in the middle cerebral artery trended towards significance (P=0.097) between the NOC and OC groups. In the NOC group, the decrease in CFV was greatest during the late follicular phase (M: −2.1 ± 3.0; LF: −6.4 ± 2.9; ML: −3.9 ± 3.5 %) while in the OC group, the decrease was least during late follicular phase (M: −6.2 ±3.3; LF: −3.7 ± 3.2; ML: −6.0 ± 3.8 %). This appeared to be due to a lack of cerebrovasodilation in the NOC group during the late follicular phase, which was also trending towards significance (P=0.082). There was also no significant effect of oral contraceptives or menstrual cycle phase on the change in heart rate between steady‐state sitting and standing. Despite the trend toward greater drops in CFV in the NOC group during late follicular phase, there was no difference in seated internal carotid blood flow between groups or across the phases of the menstrual cycle. Due to the small number of subjects currently enrolled in the study, we must be cautious in the interpretation of the data. These data suggest that in women who are not on oral contraceptives, cerebral blood flow may be slightly lower when standing during the late follicular phase, but overall baseline global brain blood flow unaffected. In addition, it appears that women on oral contraceptives had higher blood pressures. Futurework is being performed to confirm these findings in a larger group of women. This study was conducted in compliance with the Declaration of Helsinki.Support or Funding InformationThis work was supported by the War Related Illness and Injury Study Center and Deptartment of Veteran Affairs.
SHEAR STRESS INCREASES SIRTUIN 3 EXPRESSION AND PROMOTES MITOCHONDRIAL FUNCTIONS IN ENDOTHELIAL CELLS
Authors: Wang Ling Danny 
Published: November 2023

Hemodynamic shear flow‐induced atheroprotective responses in endothelial cells (ECs) have been intensively studied. However, the effects of shear flow on mitochondrial biology and its function in ECs remain unclear. Sirtuin 3 (SIRT 3), a member of Sirtuins family proteins that belong to a class of NAD+‐dependent deacetylases, is predominantly located in the mitochondria. Our previous studies have shown that SIRT 3 promotes mitochondrial homeostasis in ECs. In the present study, we studied the shear effects on SIRT 3 expression and mitochondrial homeostasis in ECs. Cultured ECs were subjected to a constant shear flow with shear stress of 12 dynes/cm2 generated by a parallel‐plate flow chamber system. Shear stress increased SIRT 3 expression and NAD+/NADPH ratio. Mitochondrial biogenesis, dynamics and functions were analyzed from sheared‐ECs. Shear flow promoted mitochondrial biogenesis as shown by the elevated levels of PGC‐1α, mitochondrial transcriptional factor A (TFAM) and mitochondrial proteins. Shear‐exposed ECs showed an increment of mitochondrial fusion revealed by the expansion of mitochondrial interconnected tubular formation. This phenomenon was coupled with an increased expression of fusion proteins (MFN2, OPA1) but a decreased fission protein (FIS1). Consistently, an increase of S637 phosphorylation and a decreased S616 phosphorylation of Drp1 were observed, indicating that shear promotes mitochondrial fusion process. Shear flow increased the expression of mitochondrial antioxidant enzymes MnSOD2, TRX2, PRX3 and PRX5. As a consequence, mitochondrial functions of sheared ECs were enhanced as revealed by a decreased mitochondrial ROS levels and an increased mitochondrial membrane potential and ATP production. Our results clearly demonstrate that ECs under shear stress increase SIRT3 expression and activity that directly or indirectly promote mitochondrial homeostasis. Thus, shear flow is essential for maintaining mitochondrial homeostasis in vascular ECs.Support or Funding InformationSUPPORTED BY MINISTER OF SCIENCE AND TECHNOLOGY, TAIWAN
Elevated endothelial microparticles induce inflammation to impair endothelial function in patients with congenital heart diseases
Authors: Ou Jingsong , Lin Ze‐Bang , Ci Hong‐Bo , Ou Zhi‐Jun , Li Yan , Liu Dong‐Hong , Wang Zhi‐Ping 
Published: November 2023

ObjectiveWe have demonstrated that endothelial microparticles (EMPs) increased in mitral valve diseases and impaired valvular endothelial cells function. Inflammation is one of the major risk factors in cardiac surgery. In this study, we investigate whether EMPs increase in congenital heart diseases and the effects of EMPs on inflammation and endothelial function.MethodsThe level of plasma EMPs in 20 patients with atrial septal defect (ASD), 23 patients with ventricular septal defect (VSD), and in 30 healthy subjects were analyzed by flow cytometry. EMPs generated from human umbilical vascular endothelial cells (HUVECs) were injected into C57BL6 mice for 6 hours, or cultured with HUVECs with/without P38 MAPK siRNAs. The expression and/or phosphorylation of endothelial nitric oxide synthase (eNOS), P38 and caveolin‐1 in mice heart and/or cultured HUVECs were determined. The nitric oxide (NO) generation in mice hearts was measured. The production of tumor necrosis factor‐a (TNF‐a) and interleukin (IL)‐6 in cultured HUVECs were detected.ResultsEMPs were significantly elevated in patients with ASD and VSD, especially in those with pulmonary hypertension. EMPs increased caveolin‐1 expression and P38 phosphorylation, decreased eNOS phosphorylation and NO production in hearts. EMPs stimulated P38 expression and TNF‐a and IL‐6 release, which could be inhibited by P38 MAPK siRNAs in cultured HUVECs.ConclusionsOur study demonstrated that EMPs were increased in patients with congenital heart diseases. The increased of EMPs could induce inflammation to impair endothelial function. P38 MAPK pathway may play a vital role in EMPs induced inflammation and provide a therapeutic target.Support or Funding InformationThis study was supported by the National Natural Science Foundation of China (81170271, 81370370 and Distinguished Young Scholar 81325001), the Changjiang Scholars Program from Ministry of Education of China, the Guangdong Pearl River Scholars Program, 973 project (2009CB522104) and International Cooperation Project (2015DFA31070) from the Ministry of Science and Technology of China, Guangdong Natural Science Fund Committee, China (2015A030312009), Sun Yat‐Sen University Clinical Research 5010 Program; Program of National Key Clinical Specialties, the Science and Technology Research for the Returned Overseas Chinese Scholars from Ministry of Human Resources and Social Security of China (2011).
Vascular effects of alpha hemoglobin stabilizing protein deletion
Authors: Biwer Lauren , Lechauve Christophe , Billaud Marie , Weiss Michell , Isakson Brant 
Published: November 2023

Hemoglobin H is a tetramer made up of 2 alpha globin subunits and 2 beta globin subunits. The alpha globin subunit requires chaperone activity by alpha hemoglobin stabilizing protein (AHSP) in order to properly associate with hemoglobin beta. In addition to erythrocytes, alpha globin is expressed in endothelial cells (EC), specifically in the small projections of the EC that make contact with the neighboring smooth muscle cells (SMC), known as myoendothelial junctions (MEJ). Immuno‐transmission electron microscopy indicates that AHSP is expressed in EC and the MEJ but not SMC of C57Bl/6 resistance arteries. There is no expression of vascular AHSP in the global AHSP knockout mice. Correlating with its role as a chaperone protein for alpha globin, 32% of AHSP is found in the EC while 60% is found in the MEJ. The percent distribution of alpha globin beads in the EC and MEJ is 35% and 60%, respectively. In AHSP −/−mice, we found that alpha globin “un‐polarizes” from the MEJ and is more equivalently spread throughout the EC and MEJ (47% and 41.5%). To determine if AHSP is regulating alpha globin distribution, we immunoprecipitated eNOS and blotted for alpha globin. In a concentration‐dependent manner, AHSP competed off eNOS for binding to alpha globin. This correlated with data from AHSP−/− mice where an increase in alpha globin‐eNOS interaction was found via PLA signal. We hypothesized that the increase in alpha globin/eNOS interaction may then alter available nitric oxide. Indeed, using radiotelemetery blood pressure measurements, we found that mean arterial pressure in AHSP−/− mice was significantly increased. These results hint that deletion of AHSP may strengthen the interaction between alpha globin and eNOS resulting in altered blood pressure stasis.Support or Funding InformationAmerican Heart AssociationNational Institute of Health