scholarly journals Signal Transduction in Cerebral Arteries after Subarachnoid Hemorrhage—A Phosphoproteomic Approach

2013 ◽  
Vol 33 (8) ◽  
pp. 1259-1269 ◽  
Author(s):  
Benjamin L Parker ◽  
Martin Røssel Larsen ◽  
Lars IH Edvinsson ◽  
Gro Klitgaard Povlsen

After subarachnoid hemorrhage (SAH), pathologic changes in cerebral arteries contribute to delayed cerebral ischemia and poor outcome. We hypothesize such changes are triggered by early intracellular signals, targeting of which may prevent SAH-induced vasculopathy. We performed an unbiased quantitative analysis of early SAH-induced phosphorylations in cerebral arteries and evaluated identified signaling components as targets for prevention of delayed vasculopathy and ischemia. Labeled phosphopeptides from rat cerebral arteries were quantified by high-resolution tandem mass spectrometry. Selected SAH-induced phosphorylations were validated by immunoblotting and monitored over a 24-hour time course post SAH. Moreover, inhibition of key phosphoproteins was performed. Major SAH-induced phosphorylations were observed on focal adhesion complexes, extracellular regulated kinase 1/2 (ERK1/2), calcium calmodulin-dependent kinase II, signal transducer and activator of transcription (STAT3) and c-Jun, the latter two downstream of ERK1/2. Inhibition of ERK1/2 6-hour post SAH prevented increases in cerebrovascular constrictor receptors, matrix metalloprotease-9, wall thickness, and improved neurologic outcome. STAT3 inhibition partially mimicked these effects. The study shows that quantitative mass spectrometry is a strong approach to study in vivo vascular signaling. Moreover, it shows that targeting of ERK1/2 prevents delayed pathologic changes in cerebral arteries and improves outcome, and identifies SAH-induced signaling components downstream and upstream of ERK1/2.

2014 ◽  
Vol 35 (2) ◽  
pp. 329-337 ◽  
Author(s):  
Gro K Povlsen ◽  
Lars Edvinsson

Cerebral vasospasm and late cerebral ischemia (LCI) remain leading causes of mortality in patients experiencing a subarachnoid hemorrhage (SAH). This occurs typically 3 to 4 days after the initial bleeding and peaks at 5 to 7 days. The underlying pathophysiology is still poorly understood. Because SAH is associated with elevated levels of endothelin-1 (ET-1), focus has been on counteracting endothelin receptor activation with receptor antagonists like clazosentan, however, with poor outcome in clinical trials. We hypothesize that inhibition of intracellular transcription signaling will be an effective approach to prevent LCI. Here, we compare the effects of clazosentan versus the MEK1/2 blocker U0126 in a rat model of SAH. Although clazosentan directly inhibits the contractile responses in vivo to ET-1, it did not prevent SAH-induced upregulation of ET receptors in cerebral arteries and did not show a beneficial effect on neurologic outcome. U0126 had no vasomotor effect by itself but counteracts SAH-induced receptor upregulation in cerebral arteries and improved outcome after SAH. We suggest that because SAH induces elevated expression of several contractile receptor subtypes, it is not sufficient to block only one of these (ET receptors) but inhibition of transcriptional MEK1/2-mediated upregulation of several contractile receptors may be a viable way towards alleviating LCI.


Stroke ◽  
2001 ◽  
Vol 32 (suppl_1) ◽  
pp. 359-360
Author(s):  
Robert L Macdonald ◽  
Bak Yamini ◽  
Bryce K Weir ◽  
Shigeki Ono

P114 Nitric oxide (NO) may be important in vasospasm following subarachnoid hemorrhage (SAH). We evaluated the time course of changes in 3 isoforms of NO synthase (NOS) after SAH in monkeys. Right SAH was created and vasospasm was assessed on angiograms obtained at baseline and after 3, 7 and 14 days. Animals were euthanized at these times (n = 4 - 6 per time) and the right and left (control) middle cerebral arteries were removed. Levels of nNOS, eNOS and iNOS messenger ribonucleic acid (mRNA) and protein were measured by reverse transcriptase polymerase chain reaction and Western blotting. Angiography showed a 45 ± 13% (mean ± s.d., p < 0.05) decrease in middle cerebral artery diameter 3 days, a 41 ± 23% (p< 0.05) decrease 7 days and an insignificant 6 ± 14% decrease 14 days after SAH. The RNA for eNOS was significantly reduced (1.7 ± 0.5-fold) 7 days after SAH. There was a significant, 1.7 ± 0.2-fold reduction in eNOS protein on days 3 and 7 after SAH that returned to normal by day 14. There were no significant changes in nNOS mRNA or protein at any time after SAH. There were no significant changes in iNOS mRNA whereas iNOS protein increased on days 3 and 7 (7 ± 9 and 2.7 ± 2.8-fold, respectively, p > 0.05) and significantly decreased (2.7 ± 1.1-fold, p < 0.05) on day 14. Immunohistochemistry localized eNOS to endothelium, nNOS to brain and perivascular adventitia of the middle cerebral arteries and iNOS to inflammatory cells in the subarachnoid space. These results show a correlation between decreased eNOS and increased iNOS during vasospasm, suggesting a complex role for changes in NO in vasospasm.


2020 ◽  
pp. 1-9
Author(s):  
Michael Veldeman ◽  
Daniel Lepore ◽  
Anke Höllig ◽  
Hans Clusmann ◽  
Christian Stoppe ◽  
...  

OBJECTIVEAneurysmal subarachnoid hemorrhage (aSAH) initiates a deleterious cascade activating multiple inflammatory processes, which can contribute to delayed cerebral ischemia (DCI). Procalcitonin (PCT) is an established marker for sepsis treatment monitoring, and its time course in the context of DCI after aSAH remains unclear. The aim of this trial was to assess the predictive and confirmative value of PCT levels in the context of DCI.METHODSAll patients admitted to the authors’ institution with aSAH between 2014 and 2018 were prospectively screened for eligibility. Daily PCT levels were recorded alongside relevant aSAH characteristics. The predictive and confirmative values of PCT levels were assessed using a receiver operating characteristic and area under the curve (AUC) analysis. The course of PCT levels around the DCI event was evaluated in an infection-free subgroup of patients.RESULTSA total of 132 patients with aSAH were included. Early PCT levels (first 3 days post-aSAH) had a low predictive value for the development of DCI (AUC 0.661, standard error [SE] 0.050; p = 0.003) and unfavorable long-term outcome (i.e., Glasgow Outcome Scale–Extended scores 1–4; AUC 0.674, SE 0.054; p = 0.003). In a subgroup analysis of infection-free patients (n = 72), PCT levels were higher in patients developing DCI (p = 0.001) and DCI-related cerebral infarction (p = 0.002). PCT concentrations increased gradually after DCI and decreased with successful intervention. In refractory cases progressing to cerebral infarction, PCT levels showed a secondary increase.CONCLUSIONSEarly higher PCT levels were associated with the later development of DCI and unfavorable outcome. Analysis of PCT beyond the first couple of days after hemorrhage is hampered by nosocomial infections. In infection-free patients, however, PCT levels rise during DCI and an additional increase develops in patients developing cerebral infarction.Clinical trial registration no.: NCT02142166 (clinicaltrials.gov)


Stroke ◽  
2021 ◽  
Vol 52 (Suppl_1) ◽  
Author(s):  
Matthew Triano ◽  
Maite J Corbin ◽  
Sameer Desale ◽  
Ai-Hsi Liu ◽  
Daniel R Felbaum ◽  
...  

Introduction: Although transcranial Doppler (TCD) evaluation for vasospasm remains an important study in aneurysmal subarachnoid hemorrhage (aSAH) management, its precise role in predicting delayed cerebral ischemia (DCI) remains unclear. Hypothesis: We evaluated optimal measures for evaluating TCD velocities and hypothesized that TCD velocity change would be the best predictor for DCI in patients with aSAH. Methods: Patients with aSAH over a two-year period were retrospectively analyzed. Baseline characteristics, outcomes, and TCD velocities in bilateral middle cerebral arteries (MCA) for hospital days 2 to14 were recorded. TCD variables, including absolute velocity and change in velocity, were obtained by creating a smoothing curve. A variable representing change in TCD velocity was then created through a linear regression model that confirmed greatest change in velocity associated with DCI occurred at days 2-7. Multivariate logistic regression analysis using DCI as outcome was then completed. Results: 95 patients with aSAH were evaluated. Increased TCD velocity at days 2-7 proved to be a better predictor for DCI than absolute velocity with an optimal cutoff of 8.9 cm/sec/day ( p = 0.019) and AUC 0.651. Multivariate logistic analysis using DCI as the outcome showed that poor admission Hunt-Hess scores (OR 5.02, 95%CI 1.22-22.67, p = 0.028) and increase in TCD velocity during days 2-7 (OR 5.32, 95%CI 1.41-23.33, p = 0.018) were independently associated with DCI. Conclusions: We found that relative increases in TCD velocities in the MCAs during the first 7 days (threshold increase of 8.9 cm/sec/day or 53.4 cm/sec from days 2-7) after aSAH were independently associated with DCI. Our findings suggest that vasospasm should be confirmed and treated aggressively when detected via increased TCD velocities during the first seven days in order to minimize DCI. This association requires independent confirmation.


1980 ◽  
Vol 53 (4) ◽  
pp. 480-485 ◽  
Author(s):  
Ramiro D. Lobato ◽  
Jesús Marín ◽  
Mercedes Salaices ◽  
Fernando Rivilla ◽  
Javier Burgos

✓ This study analyzes the time course of the changes induced by subarachnoid hemorrhage (SAH) in the sensitivity of cat cerebral arteries to noradrenaline and serotonin. Cerebral arteries displayed a supersensitivity to these amines, which was most marked 3 days after the experiment and then gradually disappeared. The supersensitivity to serotonin was greater and longer than the response to noradrenaline. The increased in the vascular contractile response induced by SAH was similar to that seen after superior cervical ganglionectomy or intracisternal injections of 6-hydroxydopamine. It is suggested that supersensitivity to noradrenaline and serotonin induced by SAH may be involved in the production of chronic cerebral vasospasm.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sami Ridwan ◽  
Alexander Grote ◽  
Matthias Simon

AbstractInterleukin 6 (IL-6) is a prominent proinflammatory cytokine and has been discussed as a potential biomarker for delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage. In the present study we have analyzed the time course of serum and cerebrospinal fluid (CSF) IL-6 levels in 82 patients with severe aneurysmal subarachnoid hemorrhage (SAH) requiring external ventricular drains in correlation to angiographic vasospasm, delayed cerebral ischemia, secondary infarctions and other clinical parameters. We observed much higher daily mean IL-6 levels (but also large interindividual variations) in the CSF than the serum of the patients with a peak between days 4 and 14 including a maximum on day 5 after SAH. Individual CSF peak levels correlated significantly with DCI (mean day 4–14 peak, DCI: 26,291 ± 24,159 pg/ml vs. no DCI: 16,184 ± 13,163 pg/ml; P = 0.023). Importantly, CSF IL-6 levels differed significantly between cases with DCI and infarctions and patients with DCI and no infarction (mean day 4–14 peak, DCI with infarction: 37,209 ± 26,951 pg/ml vs. DCI, no infarction: 15,123 ± 11,239 pg/ml; P = 0.003), while findings in the latter patient group were similar to cases with no vasospasm (mean day 4–14 peak, DCI, no infarction: 15,123 ± 11,239 vs. no DCI: 15,840 ± 12,979; P = 0.873). Together, these data support a potential role for elevated CSF IL-6 levels as a biomarker for DCI with infarction rather than for DCI in general. This fits well with a growing body of evidence linking neuroinflammation to ischemia and infarction, but (together with the large interindividual variations observed) limits the diagnostic usefulness of CSF IL-6 levels in SAH patients.


2021 ◽  
Vol 22 (16) ◽  
pp. 8444
Author(s):  
Julian Schwarting ◽  
Kathrin Nehrkorn ◽  
Hanhan Liu ◽  
Nikolaus Plesnila ◽  
Nicole Angela Terpolilli

Subarachnoid hemorrhage (SAH) is associated with acute and delayed cerebral ischemia. We suggested spasms of pial arterioles as a possible mechanism; however, it remained unclear whether and how pial microvasospasms (MVSs) induce cerebral ischemia. Therefore, we used in vivo deep tissue imaging by two-photon microscopy to investigate MVSs together with the intraparenchymal microcirculation in a clinically relevant murine SAH model. Male C57BL/6 mice received a cranial window. Cerebral vessels and leukocytes were labelled with fluorescent dyes and imaged by in vivo two-photon microscopy before and three hours after SAH induced by filament perforation. After SAH, a large clot formed around the perforation site at the skull base, and blood distributed along the perivascular space of the middle cerebral artery up to the cerebral cortex. Comparing the cerebral microvasculature before and after SAH, we identified three different patterns of constrictions: pearl string, global, and bottleneck. At the same time, the volume of perfused intraparenchymal vessels and blood flow velocity in individual arterioles were significantly reduced by more than 60%. Plugging of capillaries by leukocytes was observed but infrequent. The current study demonstrates that perivascular blood is associated with spasms of pial arterioles and that these spasms result in a significant reduction in cortical perfusion after SAH. Thus, the pial microvasospasm seems to be an important mechanism by which blood in the subarachnoid space triggers cerebral ischemia after SAH. Identifying the mechanisms of pial vasospasm may therefore result in novel therapeutic options for SAH patients.


Stroke ◽  
2021 ◽  
Author(s):  
Darcy Lidington ◽  
Hoyee Wan ◽  
Danny D. Dinh ◽  
Chloe Ng ◽  
Steffen-Sebastian Bolz

Background and Purpose: Circadian rhythms influence the extent of brain injury following subarachnoid hemorrhage (SAH), but the mechanism is unknown. We hypothesized that cerebrovascular myogenic reactivity is rhythmic and explains the circadian variation in SAH-induced injury. Methods: SAH was modeled in mice with prechiasmatic blood injection. Inducible, smooth muscle cell–specific Bmal1 (brain and muscle aryl hydrocarbon receptor nuclear translocator-like protein 1) gene deletion (smooth muscle–specific Bmal1 1 knockout [sm-Bmal1 KO]) disrupted circadian rhythms within the cerebral microcirculation. Olfactory cerebral resistance arteries were functionally assessed by pressure myography in vitro; these functional assessments were related to polymerase chain reaction/Western blot data, brain histology (Fluoro-Jade/activated caspase-3), and neurobehavioral assessments (modified Garcia scores). Results: Cerebrovascular myogenic vasoconstriction is rhythmic, with a peak and trough at Zeitgeber times 23 and 11 (ZT23 and ZT11), respectively. Histological and neurobehavioral assessments demonstrate that higher injury levels occur when SAH is induced at ZT23, compared with ZT11. In sm-Bmal1 KO mice, myogenic reactivity is not rhythmic. Interestingly, myogenic tone is higher at ZT11 versus ZT23 in sm-Bmal1 KO mice; accordingly, SAH-induced injury in sm-Bmal1 KO mice is more severe when SAH is induced at ZT11 compared to ZT23. We examined several myogenic signaling components and found that CFTR (cystic fibrosis transmembrane conductance regulator) expression is rhythmic in cerebral arteries. Pharmacologically stabilizing CFTR expression in vivo (3 mg/kg lumacaftor for 2 days) eliminates the rhythmicity in myogenic reactivity and abolishes the circadian variation in SAH-induced neurological injury. Conclusions: Cerebrovascular myogenic reactivity is rhythmic. The level of myogenic tone at the time of SAH ictus is a key factor influencing the extent of injury. Circadian oscillations in cerebrovascular CFTR expression appear to underlie the cerebrovascular myogenic reactivity rhythm.


2021 ◽  
Vol 12 ◽  
Author(s):  
Masayo Koide ◽  
Hannah R. Ferris ◽  
Mark T. Nelson ◽  
George C. Wellman

Subarachnoid hemorrhage (SAH) is a common form of hemorrhagic stroke associated with high rates of mortality and severe disability. SAH patients often develop severe neurological deficits days after ictus, events attributed to a phenomenon referred to as delayed cerebral ischemia (DCI). Recent studies indicate that SAH-induced DCI results from a multitude of cerebral circulatory disturbances including cerebral autoregulation malfunction. Cerebral autoregulation incorporates the influence of blood pressure (BP) on arterial diameter in the homeostatic regulation of cerebral blood flow (CBF), which is necessary for maintaining constant brain perfusion during physiological swings in systemic BP. In this study, we quantitatively examined the impact of SAH on cerebral autoregulation using a mouse endovascular perforation model and a newly developed approach combining absolute and relative CBF measurements. This method enables a direct quantitative comparison of cerebral autoregulation between individual animals (e.g., SAH vs. control or sham-operated mice), which cannot be done solely using relative CBF changes by laser Doppler flowmetry. Here, absolute CBF was measured via injection of fluorescent microspheres at a baseline BP. In separate groups of animals, in vivo laser Doppler flowmetry was used to measure relative CBF changes over a range of BP using phlebotomy and the pressor phenylephrine to lower and raise BP, respectively. Absolute CBF measurements from microspheres were then used to calibrate laser Doppler measurements to calculate the relationship between CBF and BP, i.e., “cerebral autoregulation curves.” Un-operated and sham-operated groups exhibited similar cerebral autoregulatory curves, showing comparable levels of relatively constant CBF over a range of BP from ~80 mmHg to ~130 mmHg. In contrast, SAH animals exhibited a narrower autoregulatory range of BP, which was primarily due to a decrease in the upper limit of BP whereby cerebral autoregulation was maintained. Importantly, SAH animals also exhibited a marked decrease in CBF throughout the entire range of BP. In sum, this study provides evidence of the dramatic reduction in cortical CBF and the diminished range of autoregulation after SAH. Furthermore, this novel methodology should pave the way for future studies examining pathological mechanisms and/or therapeutic strategies targeting impaired cerebral autoregulation, a pathology common to many cardiovascular and cerebrovascular disorders.


2021 ◽  
Vol 12 ◽  
Author(s):  
Aaron M. Gusdon ◽  
Jude P. J. Savarraj ◽  
Eyad Shihabeddin ◽  
Atzhiry Paz ◽  
Andres Assing ◽  
...  

Objective: Systemic inflammation after subarachnoid hemorrhage (SAH) is implicated in delayed cerebral ischemia (DCI) and adverse clinical outcomes. We hypothesize that early changes in peripheral leukocytes will be associated with outcomes after SAH.Methods: SAH patients admitted between January 2009 and December 2016 were enrolled into a prospective observational study and were assessed for Hunt Hess Scale (HHS) at admission, DCI, and modified Ranked Scale (mRS) at discharge. Total white blood cell (WBC) counts and each component of the differential cell count were determined on the day of admission (day 0) to 8 days after bleed (day 8). Global cerebral edema (GCE) was assessed on admission CT, and presence of any infection was determined. Statistical tests included student's t-test, Chi-square test, and multivariate logistic regression (MLR) models.Results: A total of 451 subjects were analyzed. Total WBCs and neutrophils decreased initially reaching a minimum at day 4–5 after SAH. Monocyte count increased gradually after SAH and peaked between day 6–8, while basophils and lymphocytes decreased initially from day 0 to 1 and steadily increased thereafter. Neutrophil to lymphocyte ratio (NLR) reached a peak on day 1 and decreased thereafter. WBCs, neutrophils, monocytes, and NLR were higher in patients with DCI and poor functional outcomes. WBCs, neutrophils, and NLR were higher in subjects who developed infections. In MLR models, neutrophils and monocytes were associated with DCI and worse functional outcomes, while NLR was only associated with worse functional outcomes. Occurrence of infection was associated with poor outcome. Neutrophils and NLR were associated with infection, while monocytes were not. Monocytes were higher in males, and ROC curve analysis revealed improved ability of monocytes to predict DCI and poor functional outcomes in male subjects.Conclusions: Monocytosis was associated with DCI and poor functional outcomes after SAH. The association between neutrophils and NLR and infection may impact outcomes. Early elevation in monocytes had an improved ability to predict DCI and poor functional outcomes in males, which was independent of the occurrence of infection.


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