Recent research on changes in genomic regulation and protein expression in intracerebral haemorrhage

Simvastatin-Ezetimibe enhances growth factor expression and attenuates neuron loss in the hippocampus in a model of intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a common and severe neurological disorder associated with high morbidity and mortality rates. Despite extensive research into its pathology, there are no clinically approved neuroprotective treatments for ICH. Increasing evidence has revealed that inflammatory responses mediate the pathophysiological processes of brain injury following ICH. Experimental ICH was induced by direct infusion of 100 μL fresh (non‐heparinized) autologous whole blood into the right basal ganglia of Sprague–Dawley rats at a constant rate (10 μL/min). The simvastatin group was administered simvastatin (15 mg/kg) and the combination therapy group was administered simvastatin (10 mg/kg) and ezetimibe (10 mg/kg). Magnetic resonance imaging (MRI), the forelimb use asymmetry test, the Morris water maze test, and two biomarkers were used to evaluate the effect of simvastatin and combination therapy. MRI imaging revealed that combination therapy resulted in significantly reduced perihematomal edema. Biomarker analyses revealed that both treatments led to significantly reduced endothelial inflammatory responses. The forelimb use asymmetry test revealed that both treatment groups had significantly improved neurological outcomes. The Morris water maze test revealed improved neurological function after combined therapy, which also led to less neuronal loss in the hippocampal CA1 region. In conclusion, simvastatin–ezetimibe combination therapy can improve neurological function, attenuate the endothelial inflammatory response and lead to less neuronal loss in the hippocampal CA1 region in a rat model of ICH.

MicroRNA Regulatory Network as Biomarkers of Late Seizure in Patients with Spontaneous Intracerebral Hemorrhage

Approximately 15% of patients experience seizures after spontaneous intracerebral hemorrhage (ICH). The pathogenesis of seizures post-ICH is not well-known; however, iron deposition-related neuronal injury following hemoglobin breakdown may contribute. Profiling known miRNAs to identify biomarkers for post-ICH late seizures, we found 64 differentially expressed miRNA: 32 upregulated and 32 downregulated in seizure vs. non-seizure. Functional classification of upregulated miRNA for KEGG pathways and biological processes identified enrichment for cell cycle, protein modifications, and FoxO neurotrophin signaling pathways. No significant enrichment was found for downregulated miRNA. Molecular functions Gene Ontology (GO) terms enriched for upregulated miRNA are numerous, while downregulated miRNAs were associated with ion channel activity. RT-PCR confirmed two miRNAs, 4317 and 4325, were differentially expressed in patients who developed seizures at 1 year. MiR-4317 regulates SLC38A1, a glutamine-glutamate transporter. Integrated miRNA-mRNA network analysis identified COMMD6, APOBEC2, and RASSF6-involved in NF-kB regulation. Two miRNAs (miR-4317 and 4325) differentiated post-ICH late seizures vs. non-seizures at 1 year. The results suggest functional and miRNA-mRNA networks as potential biomarkers for post-ICH late seizures.

A1 adenosine receptor attenuates intracerebral hemorrhage-induced secondary brain injury in rats by activating the P38-MAPKAP2-Hsp27 pathway

Background

This study was designed to determine the role of the A1 adenosine receptors in intracerebral hemorrhage (ICH)-induced secondary brain injury and the underlying mechanisms.

Methods

A collagenase-induced ICH model was established in Sprague–Dawley rats, and cultured primary rat cortical neurons were exposed to oxyhemoglobin at a concentration of 10 μM to mimic ICH in vitro. The A1 adenosine receptor agonist N(6)-cyclohexyladenosine and antagonist 8-phenyl-1,3-dipropylxanthine were used to study the role of A1 adenosine receptor in ICH-induced secondary brain injury, and antagonists of P38 and Hsp27 were used to study the underlying mechanisms of A1 adenosine receptor actions.

Results

The protein level of A1 adenosine receptor was significantly increased by ICH, while there was no significant change in protein levels of the other 3 adenosine receptors. In addition, the A1 adenosine receptor expression could be increased by N(6)-cyclohexyladenosine and decreased by 8-phenyl-1,3-dipropylxanthine under ICH conditions. Activation of the A1 adenosine receptor attenuated neuronal apoptosis in the subcortex, which was associated with increased phosphorylation of P38, MAPK, MAPKAP2, and Hsp27. Inhibition of the A1 adenosine receptor resulted in opposite effects. Finally, the neuroprotective effect of the A1 adenosine receptor agonist N(6)-cyclohexyladenosine was inhibited by antagonists of P38 and Hsp27.

Conclusions

This study demonstrates that activation of the A1 adenosine receptor by N(6)-cyclohexyladenosine could prevent ICH-induced secondary brain injury via the P38-MAPKAP2-Hsp27 pathway.

Neuronal tumour necrosis factor-α and interleukin-1β expression in a porcine model of intracerebral haemorrhage: Modulation by U-74389G

Tumour necrosis factor α (TNF-α) and interleukin 1β (IL-1β) are important mediators of intracerebral haemorrhage (ICH) inflammatory response. Lazaroids, established antioxidants and neuroprotectants, have been studied in several brain pathologies. The present study was designed to investigate: a) TNF-α and IL-1β changes, in neurons and b) U-74389G effects, 4 and 24h after haematoma induction in a porcine model of intracerebral haemorrhage. In twenty male landrace pigs (swines) aged 135-150 days old, autologous whole blood was injected around the right basal ganglia territory; in ten of the pigs the lazaroid compound U-74389G was administered. Brain TNF-α and IL-1β immunopositive neurons were determined by immunoarray techniques at 4 and 24h timepoints. After the haematoma induction the number of TNF-α immunopositive neurons ipsilateral to the haematoma was significantly higher compared to the contralateral site at 4h (p<0.0005), while U-74389G significantly reduced the number of TNF-α immunopositive neurons, ipsilateral to the haematoma, at 4h (p=0.002); at 24h, TNF-α immunopositive neurons were found significantly lower in the control group ipsilateral to the haematoma in comparison to 4h timepoint(p<0.0005). The number of IL-1β immunopositive neurons at 4h after the hematoma induction was significantly higher ipsilateral to the haematoma site (p<0.0005). U-74389G had no statistical significant effect. TNF-α and IL-1β, increase in neurons, 4h after the haematoma induction, ipsilateral to the haematoma site. The administration of the antioxidant compound U-74389G, results in early (at 4h) decrease of TNF-α immunopositive neurons but shows no statistical significant effect to IL-1β immunopossitive neurons.

Modulation of crucial adenosinetriphosphatase activities due to U-74389G administration in a porcine model of intracerebral hemorrhage

Spontaneous intracerebral hemorrhage (ICH) represents a partially-understood cerebrovascular disease of high incidence, morbidity and mortality. We, herein, report the findings of our study concerning the role of two important adenosinetriphosphatases (ATPases) in a porcine model of spontaneous ICH that we have recently developed (by following recent references as well as previously-established models and techniques), with a focus on the first 4 and 24 h following the lesion's induction, in combination with a study of the effectiveness of the lazaroid antioxidant U-74389G administration. Our study demonstrates that the examined ICH model does not cause a decrease in Na(+),K(+)-ATPase activity (the levels of which are responsible for a very large part of neuronal energy expenditure) in the perihematomal basal ganglia territory, nor a change in the activity of Mg(2+)-ATPase. This is the first report focusing on these crucial ATPases in the experimental setting of ICH and differs from the majority of the findings concerning the behavior of these (crucial for central nervous system cell survival) enzymes under stroke-related ischemic conditions. The administration of U-74389G (an established antioxidant) in this ICH model revealed an injury specific type of behavior, that could be considered as neuroprotective provided that one considers that Na(+),K(+)- and Mg(2+)-ATPase inhibition might in this case diminish the local ATP consumption.

Activation of TLR4-mediated NFkappaB signaling in hemorrhagic brain in rats

Inflammation and immunity play a crucial role in the pathogenesis of Intracerebral hemorrhage (ICH). Toll-like receptor 4- (TLR4-) mediated nuclear factor kappa-B (NFκB) signaling plays critical roles in the activation and regulation of inflammatory responses in injured brain. However, the involvement of TLR4-mediated NFκB signaling in the pathogenesis of ICH remains unknown. The present study was to evaluate the temporal profile of the expression of TLR4 and the activation of TLR4-mediated NFκB signaling in brain tissues of Wistar rats after ICH. TLR4 mRNA and protein, the phosphorylation of inhibitors of kappa B (p-IκBα), and the activity of NFκB were examined in hemorrhagic cerebral tissue by Rt-PCR, Western blots, immunohistochemistry staining, and EMSA. Compared with saline control, the TLR4 mRNA and protein significantly increased starting at 6 hours after ICH, peaked on the 3rd day after ICH, and then decreased but still maintained at a higher level on the 7th day after ICH (P < .05). The level of p-IκBα and the activity of NFκB also increased in the brain after ICH compared with saline control. The present study firstly suggests that TLR4-mediated NFκB signaling participates in the pathogenesis of ICH, which may become a therapeutic target for ICH-induced brain damage.

Simvastatin and atorvastatin improve neurological outcome after experimental intracerebral hemorrhage

BACKGROUND AND PURPOSE

This study investigates the effects of statin treatment on experimental intracerebral hemorrhage (ICH) using behavioral, histological, and MRI measures of recovery.

METHODS

Primary ICH was induced in rats. Simvastatin (2 mg/kg), atorvastatin (2 mg/kg), or phosphate-buffered saline (n=6 per group) was given daily for 1 week. MRI studies were performed 2 to 3 days before ICH, and at 1 to 2 hours and 1, 2, 7, 14, and 28 days after ICH. The ICH evolution was assessed via hematoma volume measurements using susceptibility-weighted imaging (SWI) and tissue loss using T2 maps and hematoxylin and eosin (H&E) histology. Neurobehavioral tests were done before ICH and at various time points post-ICH. Additional histological measures were performed with doublecortin neuronal nuclei and bromodeoxyuridine stainings.

RESULTS

Initial ICH volumes determined by SWI were similar across all groups. Simvastatin significantly reduced hematoma volume at 4 weeks (P=0.002 versus control with acute volumes as baseline), whereas that for atorvastatin was marginal (P=0.09). MRI estimates of tissue loss (% of contralateral hemisphere) for treated rats were significantly lower (P=0.0003 and 0.001, respectively) than for control at 4 weeks. Similar results were obtained for H&E histology (P=0.0003 and 0.02, respectively). Tissue loss estimates between MRI and histology were well correlated (R2=0.764, P<0.0001). Significant improvement in neurological function was seen 2 to 4 weeks post-ICH with increased neurogenesis observed.

CONCLUSIONS

Simvastatin and atorvastatin significantly improved neurological recovery, decreased tissue loss, and increased neurogenesis when administered for 1 week after ICH.