Increase In CBF Research Articles

Ciliary Motility Decreased by a CO2/HCO3--Free Solution in Ciliated Human Nasal Epithelial Cells Having a pH Elevated by Carbonic Anhydrase IV.

An application of CO2/HCO3--free solution (Zero-CO2) did not increase intracellular pH (pHi) in ciliated human nasal epithelial cells (c-hNECs), leading to no increase in frequency (CBF) or amplitude (CBA) of the ciliary beating. This study demonstrated that the pHi of c-hNECs expressing carbonic anhydrase IV (CAIV) is high (7.64), while the pHi of ciliated human bronchial epithelial cells (c-hBECs) expressing no CAIV is low (7.10). An extremely high pHi of c-hNECs caused pHi, CBF and CBA to decrease upon Zero-CO2 application, while a low pHi of c-hBECs caused them to increase. An extremely high pHi was generated by a high rate of HCO3- influx via interactions between CAIV and Na+/HCO3- cotransport (NBC) in c-hNECs. An NBC inhibitor (S0859) decreased pHi, CBF and CBA and increased CBF and CBA in c-hNECs upon Zero-CO2 application. In conclusion, the interactions of CAIV and NBC maximize HCO3- influx to increase pHi in c-hNECs. This novel mechanism causes pHi to decrease, leading to no increase in CBF and CBA in c-hNECs upon Zero-CO2 application, and appears to play a crucial role in maintaining pHi, CBF and CBA in c-hNECs periodically exposed to air (0.04% CO2) with respiration.

Effect of controlled blood pressure increase on cerebral blood flow velocity and oxygenation in patients with subarachnoid haemorrhage.

Patients with aneurysmal subarachnoid haemorrhage (SAH) might have impaired cerebral autoregulation, that is, CBF - and thereby oxygen delivery - passively increase with an increase in CPP. This physiological study aimed to investigate the cerebral haemodynamic effects of controlled blood pressure increase in the early phase after SAH before any signs of delayed cerebral ischaemia (DCI) occurred. The study was carried out within 5 days after ictus. Data were recorded at baseline and after 20 min of noradrenaline infusion to increase mean arterial blood pressure (MAP) by a maximum of 30 mmHg and to an absolute level of no more than 130 mmHg. The primary outcome was the difference in middle cerebral artery blood flow velocity (MCAv) measured by transcranial Doppler (TCD), while differences in intracranial pressure (ICP), brain tissue oxygen tension (PbtO2 ), and microdialysis markers of cerebral oxidative metabolism and cell injury were assessed as exploratory outcomes. Data were analysed using Wilcoxon signed-rank test with correction for multiplicity for the exploratory outcomes using the Benjamini-Hochberg correction. Thirty-six participants underwent the intervention 4 (median, IQR: 3-4.75) days after ictus. MAP was increased from 82 (IQR: 76-85) to 95 (IQR: 88-98) mmHg (p-value: <.001). MCAv remained stable (baseline, median 57, IQR: 46-70 cm/s; controlled blood pressure increase, median: 55, IQR: 48-71 cm/s; p-value: .054), whereas PbtO2 increased significantly (baseline, median: 24, 95%CI: 19-31 mmHg; controlled blood pressure increase, median: 27, 95%CI: 24-33 mmHg; p-value <.001). The remaining exploratory outcomes were unchanged. In this study of patients with SAH, MCAv was not significantly affected by a brief course of controlled blood pressure increase; despite this, PbtO2 increased. This suggests that autoregulation might not be impaired in these patients or other mechanisms could mediate the increase in brain oxygenation. Alternatively, a CBF increase did occur that, in turn, increased cerebral oxygenation, but was not detected by TCD. clinicaltrials.gov (NCT03987139; 14 June 2019).

Influence of cerebral blood flow on volumetric loss related to Alzheimer's disease.

Verify the correlation between atrophy and CBF in patients with MCI and mild phase ADD, to demonstrate whether changes in CBF can be considered as vascular biomarkers in the diagnosis of the DA continuum. 11 healthy volunteers, 16 MCI and 15 mild ADD were evaluated. Images of the brain were acquired, including CBF measured with Arterial Spin Labeling (ASL). When comparing MCI with control, a reduction in normalized CBF was observed in left posterior cingulate (estimated difference -0.38; p=0.02), right posterior cingulate (estimated difference -0.45; p=0.02) and right precuneus (estimated difference -0.28; p <0.01); also increase in normalized CBF in right upper temporal pole (estimated difference 0.22; p=0.03). It was also observed that in MCI, the smaller the gray matter volume, the smaller the CBF in the left posterior cingulate; as well as the greater the cerebrospinal fluid volume, consequent to the encephalic volumetric reduction associated with atrophy, the greater the CBF in the right superior temporal pole. When comparing controls, MCI and mild AD, in relation to the other variables, no other correlations were observed between CBF and atrophy. In patients with MCI, the reduction of CBF in the left posterior cingulate correlated with gray matter atrophy, as well as the increase of CBF in the right upper temporal pole correlated with an increase in cerebrospinal fluid consequent to the encephalic volumetric reduction associated with atrophy, demonstrating the influence of CBF in AD related brain atrophy. These findings position CBF as a possible vascular biomarker for early-stage AD diagnoses.

Abstract P339: A Possible Role Of Neuronal Adam17 In The Development Of Hypertension And Related Cognitive Impairment By Altering The Microenvironment

Hypertension is one of the most prevalent cardiovascular diseases worldwide and is known to be dominated by the sympathetic nervous system (SNS). Previously, we found that targeting A Disintegrin and Metalloproteinase 17 (ADAM17) in glutamatergic neurons was able to blunt Ang-II-induced excitation of pre-autonomic neurons, and blocked DOCA-salt treatment-induced sympatho-excitation in mice, thereby alleviating their development of hypertension. However, how ADAM17 support the activation of pre-autonomic neurons remains unknown. Beyond the glutamatergic neurons, we found in the current study that microglial activation and increase of pro-inflammatory cytokine levels in the hypothalamus, induced by DOCA-salt treatment, were blunted in those mice with ADAM17 knockout in glutamatergic neurons (A17G; number of CD11b+cells per line: NT+DOCA vs. A17G+DOCA= 11±2 vs. 6±1, P= 0.0017; normalized TNFα level: NT+DOCA vs. A17G+DOCA= 1.00±0.37 vs. 0.67±0.11, P&lt; 0.05; normalized IL-6 level: 1.00±0.32 vs. 0.59±0.20, P&lt; 0.05). Especially, it also reversed DOCA-salt-induced downregulation of Gad67 mRNA expression (NT= 1.00±0.11, NT+DOCA= 0.66±0.12, A17G= 1.02±0.15, A17G+DOCA= 1.67±0.24 fold of change, NT vs. NT+DOCA and A17G vs. A17G+DOCA: P&lt; 0.05), and normalized the decreased level of GABA in hypothalamus (normalized GABA levels: NT= 1.00±0.15, NT+DOCA= 0.84±0.09, A17G+DOCA= 1.09±0.17, NT vs. NT+DOCA: P&lt; 0.05), suggesting that in addition to the effect of ADAM17 on the neuron itself, it might also regulate the SNS through altering the neuronal microenvironment. In L-NAME hypertensive model, though A17G mice showed no improvement in NOS-blockade-induced dysfunction of neuro-vascular coupling (increase of CBF induced by whisker-stimulation: NT vs. A17G= 24.34±11.20 vs. 24.87±15.78 PU%), it did exhibit improved performance in Barnes maze test (latency time: NT vs. A17G= 32.77±19.36 vs. 95.54±59.03 s, P= 0.002), suggesting that ADAM17 in glutamatergic is critical for the process of neuronal damage induced by hypoxia and ischemia, possibly through modulating the homeostasis of neuronal microenvironment.

Noninvasive Follow-up Imaging of Ruptured Pediatric Brain AVMs Using Arterial Spin-Labeling.

Brain AVMs represent the main etiology of pediatric intracranial hemorrhage. Noninvasive imaging techniques to monitor the treatment effect of brain AVMs remain an unmet need. In a large cohort of pediatric ruptured brain AVMs, we aimed to investigate the role of arterial spin-labeling for the longitudinal follow-up during treatment and after complete obliteration by analyzing CBF variations across treatment sessions. Consecutive patients with ruptured brain AVMs referred to a pediatric quaternary care center were prospectively included in a registry that was retrospectively queried for children treated between 2011 and 2019 with unimodal or multimodal treatment (surgery, radiosurgery, embolization). We included children who underwent an arterial spin-labeling sequence before and after treatment and a follow-up DSA. CBF variations were analyzed in univariable analyses. Fifty-nine children with 105 distinct treatment sessions were included. The median CBF variation after treatment was -43 mL/100 mg/min (interquartile range, -102-5.5), significantly lower after complete nidal surgical resection. Following radiosurgery, patients who were healed on the last DSA follow-up demonstrated a greater CBF decrease on intercurrent MR imaging, compared with patients with a persisting shunt at last follow-up (mean, -62 [SD, 61] mL/100 mg/min versus -17 [SD, 40.1] mL/100 mg/min; P = .02). In children with obliterated AVMs, recurrences occurred in 12% and resulted in a constant increase in CBF (mean, +89 [SD, 77] mL/100 mg/min). Our results contribute data on the role of noninvasive arterial spin-labeling monitoring of the response to treatment or follow-up after obliteration of pediatric AVMs. Future research may help to better delineate how arterial spin-labeling can assist in decisions regarding the optimal timing for DSA.

Hyperperfusion Tmax mapping for nonconvulsive status epilepticus in the acute setting: A pilot case-control study.

Nonconvulsive status epilepticus (NCSE) is misdiagnosed in >50% of cases in the emergency department. Computed tomographic perfusion (CTP) has been implemented in the hyperacute setting to detect seizure-induced hyperperfusion. However, the diagnostic value of CTP is limited by the lack of thresholds for hyperperfusion and high interrater variability. This pilot case-control study aims at identifying the diagnostic value of reverse Tmax (rTmax) in differentiating NCSE from acute ischemic stroke in the hyperacute setting. We enrolled patients with NCSE (Salzburg criteria-based diagnosis) and stroke cases 1:1 matched for clinical features and time of presentation. CTP standard maps (mean transit time [MTT]-cerebral blood volume-cerebral blood flow [CBF]) and rTmax maps were elaborated and rated by two experts in CTP blinded to the final diagnosis. Hyperperfusion was adjudicated for standard CTP maps as an increase in CBF and a decrease in MTT, and for rTmax as the presence of a black area on 3-, 2-, and 1-s threshold maps. Cronbach alpha was used for interrater agreement; receiver operating curve analysis was run to measure accuracy with area under the curve. Overall, 34 patients were included (17 NCSE, 17 stroke; time from onset to imaging=2h for both groups). People with NCSE were older and more frequently had a history of epilepsy. NCSE patients had hyperperfusion on rTmax maps in 11 of 17 cases versus zero of 17 in stroke. Intra- and interrater reliability was higher for rTmax than for standard CTP maps (κ= 1 vs. κ=.6). rTmax was 82% (95%CI=67-97%) accurate in predicting NCSE versus stroke in the hyperacute setting. Agreement between neuroimaging and electroencephalography (EEG) was limited at a hemispheric level for standard CTP maps, whereas rTMax had agreement with EEG largely reaching the sublobar level. rTmax mapping might represent a reliable tool to spot NCSE-induced hyperperfusion with a threshold-based reproducible approach. Further studies are needed for validation and implementation in the differential diagnosis of focal neurological deficit in the hyperacute setting.

Enhancement of airway ciliary beating mediated via voltage-gated Ca2+ channels/α7-nicotinic receptors in mice.

Acetylcholine (ACh), which activates muscarinic ACh receptors (mAChRs) and nicotinic ACh receptors (nAChRs), enhances airway ciliary beating by increasing the intracellular Ca2+ concentration ([Ca2+]i). The mechanisms enhancing airway ciliary beating by nAChRs have remained largely unknown, although those by mAChRs are well understood. In this study, we focused on the effects of α7-nAChRs and voltage-gated Ca2+ channels (CaVs) on the airway ciliary beating. The activities of ciliary beating were assessed by frequency (CBF, ciliary beat frequency) and amplitude (CBD, ciliary bend distance) measured by high-speed video microscopy. ACh enhanced CBF and CBD by 25% mediated by an [Ca2+]i increase stimulated by mAChRs and α7-nAChRs (a subunit of nAChR) in airway ciliary cells of mice. Experiments using PNU282987 (an agonist of α7-nAChR) and MLA (an inhibitor of α7-nAChR) revealed that CBF and CBD enhanced by α7-nAChR are approximately 50% of those enhanced by ACh. CBF, CBD, and [Ca2+]i enhanced by α7-nAChRs were inhibited by nifedipine, suggesting activation of CaVs by α7-nAChRs. Experiments using a high K+ solution with/without nifedipine (155.5mMK+) showed that the activation of CaVs enhances CBF and CBD via an [Ca2+]i increase. Immunofluorescence and immunoblotting studies demonstrated that Cav1.2 and α7-nAChR are expressed in airway cilia. Moreover, IL-13 stimulated MLA-sensitive increases in CBF and CBD in airway ciliary cells, suggesting an autocrine regulation of ciliary beating by CaV1.2/α7-nAChR/ACh. In conclusion, a novel Ca2+ signalling pathway in airway cilia, CaV1.2/α7-nAChR, enhances CBF and CBD and activates mucociliary clearance maintaining healthy airways.

Rab27a-dependent exosomes protect against cerebral ischemic injury by reducing endothelial oxidative stress and apoptosis.

IntroductionMulticellular crosstalk within the brain tissue has been suggested to play a critical role in maintaining cerebral vascular homeostasis. Exosomes (EXs) mediated cell–cell communication, but its role in cerebral ischemic injury is largely unknown. Rab27a is one of the major genes controlling EX release. Here, we explored the role of Rab27a in regulating brain EXs secretion, and the effects of Rab27a‐mediated EXs on ischemia evoked cerebral vascular disruption and brain injury.MethodsCerebral ischemia was induced in Rab27a knockout (Rab27a−/−) and wide type (WT) mice by transient middle cerebral artery occlusion (tMCAO). Differential gene expression analysis was performed in ischemic brain tissue by using mRNA sequencing. EXs isolated from brain tissue of Rab27a−/− and WT mice (EXWT or EXRab27a−/−) were pre‐administrated into tMCAO operated Rab27a−/− mice or oxygen and glucose deprivation (OGD) treated primary brain vascular endothelial cells (ECs).ResultsWe demonstrated that Rab27a expression in the peri‐infarct area of brain was significantly elevated, which was associated with local elevation in EXs secretion. Rab27a deficiency dramatically decreased the level of EXs in brain tissue of normal and tMCAO‐treated mice, and Rab27a−/− mice displayed an increase in infarct volume and NDS, and a decrease in cMVD and CBF following tMCAO. Pre‐infusion of EXWT increased the brain EXs levels in the tMCAO operated Rab27a−/− mice, accompanied with an increase in cMVD and CBF, and a decrease in infarct volume, NDS, ROS production, and apoptosis. The effects of EXRab27a−/− infusion were much diminished although in a dose‐dependent manner. In OGD‐treated ECs, EXRab27a−/− showed less effectivity than EXWT in decreasing ROS overproduction and apoptosis, paralleling with down‐regulated expression of NOX2 and cleaved caspase‐3.ConclusionOur study demonstrates that Rab27a controls brain EXs secretion and functions, contributing to cerebral vascular protection from ischemic insult by preventing oxidative stress and apoptosis via down‐regulating NOX2 and cleaved caspase‐3 expression.

Genesis of Antibiotic Resistance (AR) LXXXV: Turbulence Modeling(TM) of Hemodynamics in Simplified Severe Sepsis Protocol‐2 (SSSP‐2)‐NCT01663701: Clinical Connotation of Monitoring ISP [BP(PP), MAP, CBF, ICP, CPPopt, Comatose GCS 3, and CCP] for Attenuation of IHM

Based on the theoretical inferences derived from industrial CFD modules: Flow‐3DÒ Hydro FD simulation Model 04; 05_sediment_transport FLOW‐3D HydroÒ, (Courtesy: Flow‐3D HydroÒ), The Beauty of Vortex Streets, May 5, 2021; Curve Fitting of Solution Data in COMSOL Multiphysics®, July 27, 2021 © 2021 BY COMSOL INC., https://earthobservatory.nasa.gov/images/90734/two‐views‐of‐von‐karman‐vortices (NASA). and hemodynamic data (SSSP‐2), here we present a plausible physiological basis for the benefit of monitoring ISP for attenuation 100% ihm in the usual care cohort of SSSP‐2 (PMID: 28973227). Hypothesis &amp; Rationale:Monitoring the ISP‐induced transient APG, eases the point of care clinical intervention for the recovery from GCS3 to homeostasis. Geometry: RBC, WBC, platelets, p47; Whole blood viscosity ~ 3 centipoise (cP) or ~0.003 Pascal second (Pa. s) p53; Blood velocity in the Human Blood Vessels: table 2.1 p63, Blood Vol. Distribution: Table 2.2, p64; Stress–Strain Curve, Fig 2.15 p 78; ISBN:9780128024089. Gov Eq: Segmental Cerebral Perfusion Pressure Equation for The Intracranial Compartment: SPP = Pd − ICP = FFR · CPP − Ge · (1 − FFR) · (ICP − Pe) (PMCID: PMC8032738; PMID: 33833266). Derivation &amp; Prospects:ISP has been shown to induce cerebral hypoperfusion in turn vasogenic edema altering contralateral/ipsilateral CBF due to increased blood flow through the anterior communicating artery (Acom). Case Report (PMCID: PMC7332508; PMID: 32637214): A 72‐year‐old male presented with the right‐sided hemiparesis and underwent MRI. MR imaging show an acute infarction of the left frontal lobe [Figure 1] and bilateral internal carotid artery (ICA) stenosis (NASCET: Rt: 90%, peak systolic velocity 425 cm/s and Lt: NASCET 70%, peak systolic velocity 212 cm/s). After 2 months, SPECT showed an decrease in CBF in the right cerebral hemisphere [Figure 2a]. INVOS‐4100 cerebral oximeter based determination of the effect of carotid clamping and shunting on oxygen saturation (rSO2) showed rSO2 readings were lower than ipsilateral rSO2 readings. SPECT showed a decrease in CBF around the infarction [Figure 2b]. SPECT indicated a contralateral increase in CBF [Figure 2b]. Tx, with free‐radical scavenger(Rx), showed an improvement in CBF, and laterality disappeared 2 weeks after CEA [Figure 2c and d]. The CBF of both sides equaled 2 weeks later [Figure 3]. Subsequent MR imaging with fluid‐attenuated inversion recovery (FLAIR) images showed a local high‐intensity lesion around a previous infarction in comparison with before CEA [Figure 4a and b]. FLAIR MR imaging 2 weeks after initial surgery confirmed the complete disappearance of the high‐intensity lesion [Figure 4c]. Taken together, the focal vasogenic edema induced neurologic impairment is shown to be alleviated by treating edema and cerebral ischemia while monitoring hemodynamic parameters. This model could be applied for the attenuation of fluid bolus augmented VKVS, collapsing of cerebral vessels leading to 100% ihm, in the usual care group in SSSP‐2 (PMID: 28973227).

Hochu-ekki-to enhanced airway ciliary beating by an [Ca2+]i increase via TRPV4 in mice

BackgroundHochu-ekki-to (TJ-41, a traditional herbal medicine) is used for preventing airway infections caused by viruss or bacterias in patients with chronic obstructive pulmonary disease (COPD). TJ-41 is known to inhibit viral adhesion and to activate mucosal immune system. However, the effects of TJ-41 on the beating cilia, which sweep away inhaled viruses and bacteria from the airways (mucociliary clearance, a host defense mechanism of lungs), still remain uncertain. Hypothesis/purposeTJ-41 may activate the airway ciliary beating, activation of which increases the rate of mucociliary clearance leading to inhibit airway infections. MethodsTJ-41 was orally administered to mice for 4–8 weeks (1.7 - 1.8 g/kg/day) and airway ciliary cells were isolated from the lungs. The frequency (CBF) and angle (CBA, an index of amplitude) of ciliary beating were measured using the high-speed video microscopy (HSVM, 500 fps), in relation to intracellular Ca2+ concentration ([Ca2+]i). Differences were considered significant p<0.05. ResultsThe TJ-41 treatment enhanced the basal CBF and CBA of airway cilia by 10% mediated via an increase in [Ca2+]i. Moreover, ionomycin (IM) at 1 nM increased CBF and CBA by elevating [Ca2+]i in airway ciliary cells from TJ-41 treated mice, but never in those from non-TJ-41 treated mice. These increases in [Ca2+]i were caused by the enhancement of temperature-dependent Ca2+ entry pathways, including transient receptor potential vanilloid 4 (TRPV4). ConclusionTJ-41 enhanced the basal CBF and CBA of airway cilia via a temperature-dependent [Ca2+]i increase and it also enhanced increases in CBF, CBA and [Ca2+]i stimulated by 1 nM IM, which never increased CBF and CBA in cells from non-treated mice. Thus, TJ-41 enhanced the temperature-dependent Ca2+ entry pathways including TRPV4. The [Ca2+]i increase, a novel action of TJ-41, may induce various pharmacological activities already reported including activation of the airway ciliary beating. These results suggest the potential of therapeutic use for patients suffering from chronic disease to improve various activities in addition to prevention of airway infections.

48-OR: Changes in Global Cerebral Blood Flow in Response to Hypoglycemia in Type 1 Diabetes Do Not Influence Awareness Status

Changes in global cerebral blood flow (gCBF) have been suggested as a mechanism for mitigating the functional impact of hypoglycemia on the brain. The impact of type 1 diabetes (T1D) or hypoglycemia awareness status is not clear. We measured gCBF during progressive lowering of plasma glucose in people with and without T1D, and with retained or impaired awareness of hypoglycemia. Methods: Fifty-one participants (15 with no diabetes (ND), 15 with T1D and normal awareness of hypoglycemia (NAH) and 21 with T1D and impaired awareness of hypoglycemia (IAH)) underwent a two-step hyperinsulinemic hypoglycemic clamp. gCBF was estimated using pseudocontinuous arterial spin labelling magnetic resonance imaging at 6 timepoints: 2 euglycemic, two in the descent phase and two hypoglycemic. gCBF was extracted using a global grey matter mask in SPM12. Statistical analysis and thresholded linear models were performed in R. Results: The mean (+ SD) glucose values at the six timepoints were 95.8 (8.0), 95.5 (9.2), 55.0 (8.3), 50.8 (5.3), 45.7 (4.3) and 45.8 (4.0) mg/dL. Symptom responses to hypoglycemia were absent in IAH. There was a significant increase in CBF in response to hypoglycemia (3-way ANOVA p = 0.04). This was driven by responses in NAH (+7.3%, p &amp;lt; 0.05) and IAH (+10.6% p &amp;lt; 0.01) with no response in ND (+3.5% p = 0.16). The response was not linear, with glucose thresholds of 55.8 mg/dL in NAH and 54.0 mg/dL in IAH (pNAH vs IAH = 0.9) with no threshold in ND. Conclusion: In people with T1D, there is a non-linear relationship between falling glucose and rising gCBF which is not related to awareness status and is not seen in health. The threshold glucose between 54 and 56 mg/dL corresponds closely with level 2 hypoglycemia cut-offs used in current clinical practice. We propose that there is a failure of cerebral vascular autoregulation in response to hypoglycemia in T1D. gCBF responses to hypoglycemia in T1D are independent of symptomatic responses and not responsible for lack of hypoglycemia awareness. Disclosure P. Jacob: None. O. Odaly: None. S. A. Amiel: Advisory Panel; Self; Diabetes UK, Medtronic, Other Relationship; Self; Sanofi, Research Support; Self; Diabetes UK, European Union, JDRF. P. Choudhary: Advisory Panel; Self; Abbott Diabetes, Insulet Corporation, Lilly Diabetes, Medtronic, Sanofi-Aventis, Speaker’s Bureau; Self; Dexcom, Inc., Novo Nordisk. Funding JDRF (3-SRA-2017-484-S-B)

PIP2 Improves Cerebral Blood Flow in a Mouse Model of Alzheimer's Disease.

Alzheimer’s disease (AD) is a leading cause of dementia and a substantial healthcare burden. Despite this, few treatment options are available for controlling AD symptoms. Notably, neuronal activity-dependent increases in cortical cerebral blood flow (CBF; functional hyperemia) are attenuated in AD patients, but the associated pathological mechanisms are not fully understood at the molecular level. A fundamental mechanism underlying functional hyperemia is activation of capillary endothelial inward-rectifying K+ (Kir2.1) channels by neuronally derived potassium (K+), which evokes a retrograde capillary-to-arteriole electrical signal that dilates upstream arterioles, increasing blood delivery to downstream active regions. Here, using a mouse model of familial AD (5xFAD), we tested whether this impairment in functional hyperemia is attributable to reduced activity of capillary Kir2.1 channels. In vivo CBF measurements revealed significant reductions in whisker stimulation (WS)-induced and K+-induced hyperemic responses in 5xFAD mice compared with age-matched controls. Notably, measurements of whole-cell currents in freshly isolated 5xFAD capillary endothelial cells showed that Kir2.1 current density was profoundly reduced, suggesting a defect in Kir2.1 function. Because Kir2.1 activity absolutely depends on binding of phosphatidylinositol 4,5-bisphosphate (PIP2) to the channel, we hypothesized that capillary Kir2.1 channel impairment could be corrected by exogenously supplying PIP2. As predicted, a PIP2 analog restored Kir2.1 current density to control levels. More importantly, systemic administration of PIP2 restored K+-induced CBF increases and WS-induced functional hyperemic responses in 5xFAD mice. Collectively, these data provide evidence that PIP2-mediated restoration of capillary endothelial Kir2.1 function improves neurovascular coupling and CBF in the setting of AD.

Early Renal Vasodilator and Hypotensive Action of Epoxyeicosatrienoic Acid Analog (EET-A) and 20-HETE Receptor Blocker (AAA) in Spontaneously Hypertensive Rats.

Cytochrome P450 (CYP-450) metabolites of arachidonic acid: epoxyeicosatrienoic acids (EETs) and 20-hydroxyeicosatetraenoic acid (20-HETE) have established role in regulation of blood pressure (BP) and kidney function. EETs deficiency and increased renal formation of 20-HETE contribute to hypertension in spontaneously hypertensive rats (SHR). We explored the effects of 14,15-EET analog (EET-A) and of 20-HETE receptor blocker (AAA) on BP and kidney function in this model. In anesthetized SHR the responses were determined of mean arterial blood pressure (MABP), total renal (RBF), and cortical (CBF) and inner-medullary blood flows, glomerular filtration rate and renal excretion, to EET-A, 5 mg/kg, infused i.v. for 1 h to rats untreated or after blockade of endogenous EETs degradation with an inhibitor (c-AUCB) of soluble epoxide hydrolase. Also examined were the responses to AAA (10 mg/kg/h), given alone or together with EET-A. EET-A significantly increased RBF and CBF (+30% and 26%, respectively), seen already within first 30 min of infusion. The greatest increases in RBF and CBF (by about 40%) were seen after AAA, similar when given alone or combined with EET-A. MABP decreased after EET-A or AAA but not significantly after the combination thereof. In all groups, RBF, and CBF increases preceded the decrease in MABP. We found that in SHR both EET-A and AAA induced renal vasodilation but, unexpectedly, no additive effect was seen. We suggest that both agents have a definite therapeutic potential and deserve further experimental and clinical testing aimed at introduction of novel antihypertensive therapy.

The calcium transporter ANNEXIN1 mediates cold-induced calcium signaling and freezing tolerance in plants.

The transient elevation of cytosolic free calcium concentration ([Ca2+ ]cyt ) induced by cold stress is a well-established phenomenon; however, the underlying mechanism remains elusive. Here, we report that the Ca2+ -permeable transporter ANNEXIN1 (AtANN1) mediates cold-triggered Ca2+ influx and freezing tolerance in Arabidopsis thaliana. The loss of function of AtANN1 substantially impaired freezing tolerance, reducing the cold-induced [Ca2+ ]cyt increase and upregulation of the cold-responsive CBF and COR genes. Further analysis showed that the OST1/SnRK2.6 kinase interacted with and phosphorylated AtANN1, which consequently enhanced its Ca2+ transport activity, thereby potentiating Ca2+ signaling. Consistent with these results and freezing sensitivity of ost1 mutants, the cold-induced [Ca2+ ]cyt elevation in the ost1-3 mutant was reduced. Genetic analysis indicated that AtANN1 acts downstream of OST1 in responses to cold stress. Our data thus uncover a cascade linking OST1-AtANN1 to cold-induced Ca2+ signal generation, which activates the cold response and consequently enhances freezing tolerance in Arabidopsis.

Abstract TP129: Intraoperative Prediction of Cerebral Hyperperfusion Syndrome After STA-MCA Bypass Surgery by a Newly Developed Hyperspectral Imaging System

Background: Superficial temporal artery (STA)-middle cerebral artery (MCA) bypass is the important treatment of moyamoya disease and other cerebral ischemic situations. However, cerebral hyperperfusion syndrome (HPS) may occur after vascular reconstructive surgery including STA-MCA bypass. 123 I-IMP-SPECT is useful to diagnose HPS after surgery, but there is no intraoperative device to predict HPS. Using intraoperative hyperspectral imaging data captured by hyperspectral camera (HSC), we can get the oxygen saturation value (SO2) of brain surface during surgery. We may predict HPS by analyzing intraoperative cerebral cortex SO2. Objective: To investigate whether the data from HSC during surgery is useful for prediction of postoperative HPS. Methods: 10 consecutive patients performed STA-MCA bypass were collected hyperspectral images of cerebral cortex by HSC before and after bypass. We got the SO2 data and analyzed the rate of change and correlation with HPS. Results: 3 patients presented temporary neurological deterioration several days after surgery and 123 I-IMP SPECT revealed focal intense increase in CBF at the sites of anastomosis. In these HPS patients, the rate of change of SO2 of cerebral cortex before and after bypass significantly increased in comparison with the patients didn’t present HPS (1.524 vs 1.089, P=0.0017). The receiver operating characteristic curve reveals if the rate of change of SO2 is more than 1.17, postoperative HPS is likely to occur (sensitivity=83%, AUC=0.81). Conclusions: Using the HSC, we may predict the occurrence of HPS after STA-MCA bypass. HSC can be the useful device in postoperative treatment for prevention of HPS.

B-42 SPECT Differences between PTSD and Healthy Controls

Abstract Objective To test whether Post-Traumatic Stress Disorder (PTSD) alters brain activity compared to a Healthy group at baseline, as measured by a single photon emission computed tomography (SPECT) imaging. Methods The sample (n = 189) included a PTSD group (n = 109, Mage = 43.4, 23% Male, 71.6% Caucasian.) and a Healthy group (n = 80, Mage = 41.5, 45 Males, 41.3% Caucasian.). Results The results revealed significant decrease (p &lt; .01) of CBF in the PTSD group in the left (F(1,187) = 9.678, p = .002) and right (F(1,187) = 7.112, p = .008) Basal Ganglia compared to the healthy group. The left (F(1,187) = 10.384, p = .002) and right (F(1,187) = 8.892, p = .003) Cerebellum and the left (F(1,187) = 5.591, p = .019) and right (F(1,187) = 5.898, p = .016) Temporal areas had significant increases in CBF in the PTSD group compared to the Healthy group. Conclusion The pattern of increased CBF in the Temporal lobes in those suffering from PTSD can be associated with personal increase in emotional responsivity. The increase in emotional lability can be related to the symptoms that are evident in PTSD, including, attention and consolidation of memory. Furthermore, the increased cerebellar CBF may affect major functions including motor movements and procedural memory. By having overactivation in these areas individuals with PTSD may experience symptoms of increased alertness, hypervigilance, and inability to control behavioral actions that have previously been learned in stressful situations. Decreased CBF in the Basal Ganglia of the PTSD group suggests an aberration of functions controlled by this area, such as, motor learning, executive functions, and reinforcement-learning. Treatment of PTSD can target discrete brain systems related to these differences in cognitive activity.

Neurovascular coupling during optogenetic functional activation: Local and remote stimulus-response characteristics, and uncoupling by spreading depression

Neurovascular coupling is a fundamental response that links activity to perfusion. Traditional paradigms of neurovascular coupling utilize somatosensory stimulation to activate the primary sensory cortex through subcortical relays. Therefore, examination of neurovascular coupling in disease models can be confounded if the disease process affects these multisynaptic pathways. Optogenetic stimulation is an alternative to directly activate neurons, bypassing the subcortical relays. We employed minimally invasive optogenetic cortical activation through intact skull in Thy1-channelrhodopsin-2 transgenic mice, examined the blood flow changes using laser speckle imaging, and related these to evoked electrophysiological activity. Our data show that optogenetic activation of barrel cortex triggers intensity- and frequency-dependent hyperemia both locally within the barrel cortex (>50% CBF increase), and remotely within the ipsilateral motor cortex (>30% CBF increase). Intriguingly, activation of the barrel cortex causes a small (∼10%) but reproducible hypoperfusion within the contralateral barrel cortex, electrophysiologically linked to transhemispheric inhibition. Cortical spreading depression, known to cause neurovascular uncoupling, diminishes optogenetic hyperemia by more than 50% for up to an hour despite rapid recovery of evoked electrophysiological activity, recapitulating a unique feature of physiological neurovascular coupling. Altogether, these data establish a minimally invasive paradigm to investigate neurovascular coupling for longitudinal characterization of cerebrovascular pathologies.

Asymmetric Cortical Vessel Sign Indicates Hemodynamic Deficits in Adult Patients with Moyamoya Disease

Asymmetric cortical vessel sign (ACVS) on susceptibility-weighted imaging (SWI) indicates elevated concentration of deoxyhemoglobin and elevated oxygen extraction fraction in patients with cerebral ischemia. This study aimed to clarify whether ACVS is associated with impaired hemodynamics and hyperperfusion syndrome in patients with moyamoya disease (MMD). Consecutive adult patients with MMD were enrolled. ACVS data on SWI and perfusion data using dynamic perfusion computed tomography were obtained and evaluated preoperatively and on postoperative days 2 and180. A total of 24 patients with MMD were enrolled. Of 11 (45.83%) patients showing positive ACVS before surgery, 8 turned negative on postoperative day 2 and 9 showed absence of ACVS 180 days after surgery. Regions of interest showing positive ACVS had lower cerebral blood flow (CBF, P<0.001), increased cerebral blood volume (P= 0.021), prolonged time to peak (P<0.001), and mean transit time (P= 0.009). No patients with hemorrhagic symptoms showed positive ACVS(P= 0.041) and patients with positive ACVS showed more increase in CBF (P<0.004). In patients with MMD, ACVS on SWI indicates severe impairment in hemodynamics and is associated with more increase in CBF after bypass surgery. Hence, ACVS on SWI might be considered as a neuroimaging marker for the evaluation of hemodynamics in patients with MMD.

Effects of Exercise Intensity on Microvascular Function in Obese Adolescents.

The optimal exercise modality for the improvement of health-related parameters and microvascular function in obese adolescents is not yet fully understood. Therefore, this study aimed to 1) compare the microvascular phenotype of obese and normal-weight adolescents; and 2) to determine the effects of a lifestyle intervention including three months of moderate continuous training (MCT) or high-intensity interval training (HIIT) on health-related parameters and microvascular function in 29 obese adolescents. Body composition, metabolic profile, aerobic fitness and cutaneous blood flow, measured using laser Doppler flowmetry at rest and during post-occlusive reactive hyperemia, were assessed prior to and following lifestyle intervention. Sixteen normal-weight adolescents were included as reference controls for baseline microvascular parameters. At baseline, obese adolescents had higher peak blood flow, peak vascular conductance and area under the curve for post-occlusive reactive hyperemia than normal-weight adolescents. Conversely, peak blood flow, peak vascular conductance and area under the curve data remained unchanged after MCT and HIIT without intergroup differences. However, the peak/basal blood flow ratio decreased in both MCT and HIIT groups without any interaction between groups due to basal CBF increase (tendency p=0.074). Exercise training, whatever the modality, does not improve peak microcirculatory function.

ЦИЛИАРНАЯ АКТИВНОСТЬ МЕРЦАТЕЛЬНОГО ЭПИТЕЛИЯ БРОНХОВ ПРИ ХОЛОДОВОМ ВОЗДЕЙСТВИИ В ЭКСПЕРИМЕНТЕ IN VITRO

To date, the role of dysfunction of the bronchial ciliated epithelium (BCE) in the formation of mucociliary disorders during cold exposure has not been fully established. The aim of the study was to investigate the nature and severity of changes in the ciliary motility of the BCE under the influence of a cold stimulus in vitro. Ten volunteers with asthma underwent a bronchoscopy with biopsy of the lobar bronchus mucosa. The biopsy specimens were placed in a Hank’s balanced salt solution (HBSS) on a slide, located on the thermal stage, used to simulate the effect of various temperature on the BCE. Ciliary beat frequency (CBF, Hz) was recorded using a microscope, high-sensitivity digital camera and computer with specially developed software. The initial recording of CBF was performed at 24ºC, after which the temperature of HBSS was gradually increased to physiological level and repeated recording was made at the control points (28ºC and 36ºC). Then, the temperature of the solution was lowered and CBF was registered again at 28ºC, 21ºC and 17ºC. The initial CBF of the BCE varied from 6.74 to 3.77 Hz with average of 5.25±1.48 Hz (M±m). There was a statistically significant increase in CBF when the solution was heated: at 28ºC it was 6.33±1.36 Hz (p=0.004) and remained at this level up to 36ºC – 7.14±1.33 Hz (p=0.002). A gradual decrease in the solution temperature produced a reduction in CBF in comparison with the physiological conditions: 28ºC – 6.12±1.31 Hz (p=0.121), 21ºC – 5.27±1.32 Hz (p=0.001) and 17ºC – 3.95±1.18 Hz (p=0.0001). By the end of the experiment, CBF of the BCE decreased almost 2-fold in comparison with the physiological conditions. A mathematical model that characterizes the behavior of BCE cilia under cold stress was developed. Thus, the results of the study demonstrate a marked decrease in the motor activity of the BCE cilia under cold stress, which underlines a significant contribution of the functional disturbance of BCE to the pathophysiological mechanisms of hypersecretory disorders induced by inhalation of cold air.