A Novel Brainstem Hemorrhage Model by Autologous Blood Infusion in Rat: White Matter Injury, Magnetic Resonance Imaging, and Neurobehavioral Features

Mesenchymal stem cells transplantation combined with IronQ attenuates ICH-induced inflammation response via Mincle/syk signaling pathway

BACKGROUND

Intracerebral hemorrhage (ICH) is a severe brain-injured disease accompanied by cerebral edema, inflammation, and subsequent neurological deficits. Mesenchymal stem cells (MSCs) transplantation has been used as a neuroprotective therapy in nervous system diseases because of its anti-inflammatory effect. Nevertheless, the biological characteristics of transplanted MSCs, including the survival rate, viability, and effectiveness, are restricted because of the severe inflammatory response after ICH. Therefore, improving the survival and viability of MSCs will provide a hopeful therapeutic efficacy for ICH. Notably, the biomedical applications of coordination chemistry-mediated metal-quercetin complex have been verified positively and studied extensively, including growth-promoting and imaging probes. Previous studies have shown that the iron-quercetin complex (IronQ) possesses extraordinary dual capabilities with a stimulating agent for cell growth and an imaging probe by magnetic resonance imaging (MRI). Therefore, we hypothesized that IronQ could improve the survival and viability of MSCs, displaying the anti-inflammation function in the treatment of ICH while also labeling MSCs for their tracking by MRI. This study aimed to explore the effects of MSCs with IronQ in regulating inflammation and further clarify their potential mechanisms.

METHODS

C57BL/6 male mice were utilized in this research. A collagenase I-induced ICH mice model was established and randomly separated into the model group (Model), quercetin gavage group (Quercetin), MSCs transplantation group (MSCs), and MSCs transplantation combined with IronQ group (MSCs + IronQ) after 24 h. Then, the neurological deficits score, brain water content (BWC), and protein expression, such as TNF-α, IL-6, NeuN, MBP, as well as GFAP, were investigated. We further measured the protein expression of Mincle and its downstream targets. Furthermore, the lipopolysaccharide (LPS)-induced BV2 cells were utilized to investigate the neuroprotection of conditioned medium of MSCs co-cultured with IronQ in vitro.

RESULTS

We found that the combined treatment of MSCs with IronQ improved the inflammation-induced neurological deficits and BWC in vivo by inhibiting the Mincle/syk signaling pathway. Conditioned medium derived from MSCs co-cultured with IronQ decreased inflammation, Mincle, and its downstream targets in the LPS-induced BV2 cell line.

CONCLUSIONS

These data suggested that the combined treatment exerts a collaborative effect in alleviating ICH-induced inflammatory response through the downregulation of the Mincle/syk signaling pathway following ICH, further improving the neurologic deficits and brain edema.

Cyclophilin D-induced mitochondrial impairment confers axonal injury after intracerebral hemorrhage in mice

The mitochondrial permeability transition pore is a nonspecific transmembrane channel. Inhibition of mitochondrial permeability transition pore opening has been shown to alleviate mitochondrial swelling, calcium overload, and axonal degeneration. Cyclophilin D is an important component of the mitochondrial permeability transition pore. Whether cyclophilin D participates in mitochondrial impairment and axonal injury after intracerebral hemorrhage is not clear. In this study, we established mouse models of intracerebral hemorrhage in vivo by injection of autologous blood and oxyhemoglobin into the striatum in Thy1-YFP mice, in which pyramidal neurons and axons express yellow fluorescent protein. We also simulated intracerebral hemorrhage in vitro in PC12 cells using oxyhemoglobin. We found that axonal degeneration in the early stage of intracerebral hemorrhage depended on mitochondrial swelling induced by cyclophilin D activation and mitochondrial permeability transition pore opening. We further investigated the mechanism underlying the role of cyclophilin D in mouse models and PC12 cell models of intracerebral hemorrhage. We found that both cyclosporin A inhibition and short hairpin RNA interference of cyclophilin D reduced mitochondrial permeability transition pore opening and mitochondrial injury. In addition, inhibition of cyclophilin D and mitochondrial permeability transition pore opening protected corticospinal tract integrity and alleviated motor dysfunction caused by intracerebral hemorrhage. Our findings suggest that cyclophilin D is used as a key mediator of axonal degeneration after intracerebral hemorrhage; inhibition of cyclophilin D expression can protect mitochondrial structure and function and further alleviate corticospinal tract injury and motor dysfunction after intracerebral hemorrhage. Our findings provide a therapeutic target for preventing axonal degeneration of white matter injury and subsequent functional impairment in central nervous diseases.

Management of Primary Brainstem Hemorrhage: A Review of Outcome Prediction, Surgical Treatment, and Animal Model

Primary brainstem hemorrhage (PBH) has the worst prognosis of all types of intracerebral hemorrhage. Currently, the management of PBH is controversial. Hematoma classification, scoring systems, and electrophysiological monitoring are critical for predicting the outcome of PBH. Surgery may be an effective treatment for PBH. Clinical studies have emphasized the importance of animal models for understanding the pathogenesis and pathological mechanisms of PBH. In this study, combined with recent studies, the outcome prediction, surgical treatment, and animal models of PBH were reviewed.

Intracerebral Hemorrhage: The Effects of Aging on Brain Injury

Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with high rates of mortality and morbidity. ICH patients often suffer devastating and debilitating neurological impairments, from which the majority of victims are unable to fully recover to functional independence. Unfortunately, there is no established medical therapy for ICH, which is partly attributed to the lack of understanding of the complex pathology of the disorder. Despite advanced age being a major risk factor of ICH, most preclinical studies on ICH employed young animal subjects. Due to this discrepancy, the molecular level changes in the aging brain after ICH are largely unknown, limiting the translation of preclinical studies into potential human treatments. The purpose of this review is to highlight the effects of advanced age on ICH- induced brain injury and recovery and to draw attention to current knowledge gaps, which warrant further investigation.

Primary Brainstem Hemorrhage: A Review of Prognostic Factors and Surgical Management

Primary brainstem hemorrhage (PBSH) is the most fatal subtype of intracerebral hemorrhage and is invariably associated with poor prognosis. Several prognostic factors are involved, of which the two most predominant and consistent are the initial level of consciousness and hemorrhage size. Other predictors, such as age, hyperthermia, and hydrocephalus, are generally not dependable indicators for making prognoses. Scoring systems have now been developed that can predict mortality and functional outcomes in patients suffering from PBSH, which can thus guide treatment decision-making. A novel grading scale, entitled “the new primary pontine hemorrhage (PPH) score,” represents the latest approach in scoring systems. In this system, patients with a score of 2–3 points appear to benefit from surgical management, although this claim requires further verification. The four main surgical options for the treatment of PBSH are craniotomy, stereotactic hematoma puncture and drainage, endoscopic hematoma removal, and external ventricular drainage. Nevertheless, the management of PBSH still primarily involves conservative treatment methods and surgery is generally not recommended, according to current practice. However, the ongoing clinical trial, entitled Safety and Efficacy of Surgical Treatment in Severe Primary Pontine Hemorrhage Evacuation (STIPE), should provide additional evidence to support the surgical treatment of PBSH. Therefore, we advocate the update of epidemiological data and re-evaluation of PBSH treatment in a contemporary context.

Monitoring of patients with brainstem hemorrhage: A simultaneous study of quantitative electroencephalography and transcranial Doppler

OBJECTIVE

To explore whether quantitative electroencephalography (QEEG) and transcranial Doppler (TCD) can be used to evaluate patients with acute severe brainstem hemorrhage (ASBH).

METHODS

We prospectively enrolled patients with ASBH and assessed their mortality at the 90-day follow-up. The patients' demographic data, serological data, and clinical factors were recorded. Quantitative brain function monitoring was performed using a TCD-QEEG recording system attached to the patient's bedside.

RESULTS

Thirty-one patients (55.3 ± 10.6 years; 17 men) were studied. Mortality at 90 days was at 61.3%. There was no significant difference in TCD-related parameters between the survival group and the death group (p > 0.05). Among the QEEG-related indexes, only the (delta + theta)/(alpha + beta) ratio (DTABR) (odds ratio 11.555, 95%confidence interval 1.413-94.503, p = 0.022) was an independent predictor of clinical outcome; the area under the ROC curve of DTABR was 0.921, cut-off point was 3.88, sensitivity was 79%, and specificity was 100%.

CONCLUSIONS

In patients with ASBH, QEEG can effectively inform the clinical prognosis regarding 90-day mortality, while TCD cannot.

SIGNIFICANCE

QEEG shows promise for informing the mortality prognosis of patients with ASBH.

Neuroprotective Methodologies of Co-Enzyme Q10 Mediated Brain Hemorrhagic Treatment: Clinical and Pre-Clinical Findings

Cerebral brain hemorrhage is associated with the highest mortality and morbidity despite only constituting approximately 10-15% of all strokes classified into intracerebral and intraventricular hemorrhage where most of the patients suffer from impairment in memory, weakness or paralysis in arms or legs, headache, fatigue, gait abnormality and cognitive dysfunctions. Understanding molecular pathology and finding the worsening cause of hemorrhage will lead to explore the therapeutic interventions that could prevent and cure the disease. Mitochondrial ETC-complexes dysfunction has been found to increase neuroinflammatory cytokines, oxidative free radicals, excitotoxicity, neurotransmitter and energy imbalance that are the key neuropathological hallmarks of cerebral hemorrhage. Coenzyme Q10 (CoQ10), as a part of the mitochondrial respiratory chain can effectively restore these neuronal dysfunctions by preventing the opening of mitochondrial membrane transition pore, thereby counteracting cell death events as well as exerts an anti-inflammatory effect by influencing the expression of NF-kB1 dependent genes thus preventing the neuroinflammation and energy restoration. Due to behavior and biochemical heterogeneity in post cerebral brain hemorrhagic pattern different preclinical autologous blood injection models are required to precisely investigate the forthcoming therapeutic strategies. Despite emerging pre-clinical research and resultant large clinical trials for promising symptomatic treatments, there are very less pharmacological interventions demonstrated to improve post operative condition of patients where intensive care is required. Therefore, in current review, we explore the disease pattern, clinical and pre-clinical interventions under investigation and neuroprotective methodologies of CoQ10 precursors to ameliorate post brain hemorrhagic conditions.

TRPA1 Activation-Induced Myelin Degradation Plays a Key Role in Motor Dysfunction After Intracerebral Hemorrhage

Intracerebral hemorrhage (ICH) is a devastating disease that is characterized by high morbidity and high mortality. ICH has an annual incidence of 10-30/100,000 people and accounts for approximately 10%-30% of all types of stroke. ICH mostly occurs at the basal ganglia, which is rich in nerve fibers; thus, hemiplegia is quite common in ICH patients with partial sensory disturbance and ectopic blindness. In the clinic, those symptoms are considered to originate from the white matter injury in the area, but the exact mechanisms are unknown, and currently, no effective drug treatments are available to improve the prognosis. Clarifying the mechanisms will contribute to the development of new treatment methods for patients. The transient receptor potential ankyrin 1 (TRPA1) channel is a non-selective cation channel that plays a role in inflammatory pain sensation and nociception and may be a potential regulator in emotion, cognition and social behavior. Here, we report that TRPA1 is involved in myelin damage and oxidative stress injury in a mouse ICH model. Intervention with the TRPA1 channel may be a new method to improve the motor function of patients in the early stage of ICH.

Rat Brainstem Hemorrhage Model: Key Points to Success in Modeling

BACKGROUND

A successful animal brainstem hemorrhage model can be used to study pathophysiology and molecular mechanisms of neurologic deterioration or recovery and therapeutic interventions after the brainstem hemorrhage. Herein, we provide a reproducible and reliable model for rat brainstem hemorrhage and summarize our key points to success in modeling.

METHODS

Twenty-four adult male Sprague-Dawley rats were divided into 3 groups and were injected with 30, 40, and 60 μL autologous blood into the right pontine basal tegmentum after being sedated. The initial model was evaluated with neurobehavior testing, autopsy, and histopathology. The modeling conditions were modified in Group IV rats, and 20 more rats were used to check the reproducibility and reliability of the modified model. Finally, magnetic resonance imaging (MRI) was used to confirm the brainstem hemorrhage.

RESULTS

Only 6 rats had significant pontine hemorrhage in initial 3 groups on autopsy. Whereas after the modification, all Group IV rats had serious pontine hemorrhage, and modified conditions model had a 90% success rate. MRI confirmed a stable hematoma in the right basal tegmental pons with oval shape 24 hours after of blood injection. Histopathologically, there was significant perihematomal swelling, migration of inflammatory cells and structural changes in neuronal shape and contents.

CONCLUSIONS

An ideal and repeatable rat brainstem hemorrhage model by injecting autologous blood stereotactically was created, and it mimics the natural onset of brainstem hemorrhage. This brainstem hemorrhage model shows promise that providing a better way for neurology researchers to investigate pathophysiologic procedure of brainstem intracranial hemorrhage and further explore the treatment.

White Matter Injury after Intracerebral Hemorrhage: Pathophysiology and Therapeutic Strategies

Intracerebral hemorrhage (ICH) accounts for 10%–30% of all types of stroke. Bleeding within the brain parenchyma causes gray matter (GM) destruction as well as proximal or distal white matter (WM) injury (WMI) due to complex pathophysiological mechanisms. Because WM has a distinct cellular architecture, blood supply pattern and corresponding function, and its response to stroke may vary from that of GM, a better understanding of the characteristics of WMI following ICH is essential and may shed new light on treatment options. Current evidence using histological, radiological and chemical biomarkers clearly confirms the spatio-temporal distribution of WMI post- ICH. Although certain types of pathological damage such as inflammatory, oxidative and neuro-excitotoxic injury to WM have been identified, the exact molecular mechanisms remain unclear. In this review article, we briefly describe the constitution and physiological function of brain WM, summarize evidence regarding WMI, and focus on the underlying pathophysiological mechanisms and therapeutic strategies.

MiR-124 contributes to M2 polarization of microglia and confers brain inflammatory protection via the C/EBP-α pathway in intracerebral hemorrhage

Microglia mediated inflammation contributes to intracerebral hemorrhage (ICH) induced secondary injury. Activated microglia has dual functions as pro-inflammatory (M1) and anti-inflammatory (M2) factors in brain injury and repair. MiR-124 is a potent anti-inflammatory agent which affects microglia after brain injury. However, the potential of modulating the M1/M2 polarization of microglia after ICH has not been reported. In this experiment, we detected the effect of miR-124 on the M1/M2 polarization state. In addition, the ability miR-124 to subsequently impacted neurological deficit and cerebral water content of ICH mice were studied. Furthermore, the relationship between miR-124 and C/EBP-α target was detected. We found that miR-124 significantly increased in M2-polarized microglia. Transduction of miR-124 mimics decreased proinflammatory cytokine levels. A coculture model of microglia and neuron indicated that M2-polarized microglia protected neuron damage. Furthermore, miR-124 banded to the 3-untranslated region of C/EBP-α and downregulated its protein levels. In vivo, infusion of miR-124 decreased brain levels of C/EBP-α and significantly reduced brain injury in ICH mice. Thus, miR-124 ameliorated ICH-induced inflammatory injury by modulating microglia polarization toward the M2 phenotype via C/EBP-α. MiR-124 regulatory mechanisms also might represent new therapeutic strategy in ICH.