TIE2 expression in hypertensive ICH and its therapeutic modulation with AKB-9778: Implications for brain vascular health.

Hypertensive intracerebral hemorrhage (ICH) is a devastating condition, the molecular underpinnings of which remain not fully understood. By leveraging high-throughput transcriptome sequencing and network pharmacology analysis, this study unveils the significant role of the tyrosine kinase with immunoglobulin-like and EGF-like domains 2 (TIE2) in ICH pathogenesis. Compared to controls, a conspicuous downregulation of TIE2 was observed in the cerebral blood vessels of hypertensive ICH mice. In vitro assays with human brain microvascular endothelial cells (HBMEC), HBEC-5i revealed that modulation of TIE2 expression significantly influences cellular proliferation, migration, and angiogenesis, mediated via the Rap1/MEK/ERK signaling pathway. Notably, the small molecule AKB-9778 was identified to target and activate TIE2, affecting the functional attributes of HBEC-5i. In vivo experiments further demonstrated that combining AKB-9778 with antihypertensive drugs could mitigate the incidence and volume of bleeding in hypertensive ICH mouse models, suggesting potential therapeutic implications.

Development and validation of the hypertensive intracerebral hemorrhage prognosis models.

To develop and validate the prognosis model of hypertensive intracerebral hemorrhage based on admission characteristics, which would be applied to predict the 3-month outcome.For developing the prognosis models, we studied data from 325 patients with retrospectively consecutive hypertensive intracerebral hemorrhage admitted between 2012 and 2016. The predictive value of admission characteristics was tested in logistic regression models, presenting 3-month outcome as the primary outcome. The performance of the models was tested by discrimination and calibration. After development, internal and external validations were used to test the function.The multivariate analysis of logistic regression indicated that age, Glasgow coma scale score, pupillary light reflex, hypoxemia, intracerebral hemorrhage volume, blood glucose, and D-dimer level were independent factors of the hypertensive intracerebral hemorrhage prognosis model. The prognosis model based on those admission risk factors worked well. The receiver operating characteristic curve was used to analyze the discriminant ability of model A, model A + B, and model A + B + C. Specifically, the area under the receiver operating characteristic curve increased from 0.816 (model A; 95% CI, 0.760-0.872) to 0.913 (model A + B + C; 95% CI, 0.881-0.946), and the models were not overoptimistic and were applicably confirmed by internal and external validations respectively.This prognosis model could be used to predict the prognosis of patients with hypertensive intracerebral hemorrhage early, simply and accurately, contributing to the clinical treatment eventually.

LncRNA-FENDRR mediates VEGFA to promote the apoptosis of brain microvascular endothelial cells via regulating miR-126 in mice with hypertensive intracerebral hemorrhage.

BACKGROUND: LncRNA-FENDRR is a kind of endothelial genes critical for vascular development. Moreover, miR-126 and vascular endothelial growth factor A (VEGFA) are also involved in the physiological process of vascular endothelial cells. This study aimed to the underlying mechanism of FENDRR involving miR-126 and VEGFA in hypertensive intracerebral hemorrhage (HICH). METHODS: C57BL/6 mice were chosen to establish HICH model. The expression of FENDRR, miR-126, and VEGFA at mRNA level was determined by qRT-PCR. The protein expression of VEGFA was assessed using Western blot. RIP assay and RNA pull-down assay were used to the relationship between FENDRR and miR-126. Flow cytometry was used to analyze cell apoptosis. RESULTS: The levels of FENDRR and VEGFA were increased, and miR-126 expression was decreased in vascular endothelial cells (VECs) from the right brain of model mice and human brain microvascular endothelial cells (HBMECs) treated by thrombin. Overexpression of FENDRR promoted the apoptosis of HBMECs. FENDRR regulating VEGFA participated in HBMECs apoptosis through targeting miR-126. Downregulation of FENDRR was indicated to relieve the HICH in mice. CONCLUSIONS: FENDRR could promote the apoptosis of HBMECs via miR-126 regulating VEGFA in HICH.

MEK/ERK- and calcineurin/NFAT-mediated mechanism of cerebral hyperemia and brain injury following NMDA receptor activation.

N-methyl-d-aspartate (NMDA) receptor activation increases regional cerebral blood flow (rCBF) and induces neuronal injury, but similarities between these processes are poorly understood. In this study, by measuring rCBF in vivo, we identified a clear correlation between cerebral hyperemia and brain injury. NMDA receptor activation induced brain injury as a result of rCBF increase, which was attenuated by an inhibitor of mitogen-activated protein kinase or calcineurin. Moreover, NMDA induced phosphorylation of extracellular signal-regulated kinase (ERK) and nuclear translocation of nuclear factor of activated T-cell (NFAT) in neurons. Therefore, a MEK/ERK- and calcineurin/NFAT-mediated mechanism of neurovascular coupling underlies the pathophysiology of neurovascular disorders.

Associations between biomarkers of renal function with cerebral microbleeds in hypertensive patients.

BACKGROUND: Cerebral microbleeds (CMBs) have been observed in the elderly and have been regarded as a manifestation of small vessel disease (SVD). Cerebral and glomerular SVD may have a common source of pathogenesis because these organs are closely connected through anatomic and hemodynamic similarities. The purpose of this study was to clarify the associations between kidney biomarker levels and CMBs in hypertensive patients. METHODS: The presence and number of CMBs were assessed on susceptibility-weighted imaging. We calculated the urinary albumin/creatinine ratio (UACR) from morning spot urine and the estimated glomerular filtration rate (eGFR) in serum samples. Serum cystatin C (CysC) was measured with an automated particle-enhanced turbidimetric immunoassay. RESULTS: UACR and CysC levels were higher in the patients with CMBs than those without, and the eGFR was lower in the patients with CMBs than those without. A logistic regression analysis indicates that eGFR and UACR were independently associated with the prevalence of deep or infratentorial CMBs. The odds ratio (OR) (95% confidence interval (CI)) of eGFR and UACR was 1.95 (1.37-3.27) and 2.25 (1.66-4.46), respectively. CysC was independently associated with CMBs in both deep or infratentorial and lobar locations. The ORs (95% CI) were 2.59 (1.57-6.22) and 1.57 (1.15-4.85), respectively. Furthermore, CysC exhibited fair diagnostic value for CMBs, with an area under the curve of 0.80. CONCLUSIONS: Kidney biomarker levels are associated with the presence of CMB in hypertensive patients without a history of transient ischemic attack (TIA) or stroke, independent of conventional risk factors, and CysC was a better marker for CMBs than eGFR and UACR.

Ablation of astrocytic laminin impairs vascular smooth muscle cell function and leads to hemorrhagic stroke.

Astrocytes express laminin and assemble basement membranes (BMs) at their endfeet, which ensheath the cerebrovasculature. The function of astrocytic laminin in cerebrovascular integrity is unknown. We show that ablation of astrocytic laminin by tissue-specific Cre-mediated recombination disrupted endfeet BMs and led to hemorrhage in deep brain regions of adult mice, resembling human hypertensive hemorrhage. The lack of astrocytic laminin led to impaired function of vascular smooth muscle cells (VSMCs), where astrocytes have a closer association with VSMCs in small arterioles, and was associated with hemorrhagic vessels, which exhibited VSMC fragmentation and vascular wall disassembly. Acute disruption of astrocytic laminin in the striatum of adult mice also impaired VSMC function, indicating that laminin is necessary for VSMC maintenance. In vitro, both astrocytes and astrocytic laminin promoted brain VSMC differentiation. These results show that astrocytes regulate VSMCs and vascular integrity in small vessels of deep brain regions. Therefore, astrocytes may be a possible target for hemorrhagic stroke prevention and therapy.

Effects of heparin on synaptic activity in the hemorrhagic stroke model in vitro.

We studied the ability of heparin to modify synaptic activity on the original stroke model in vitro. Cultured slices of the brain slices from hypertensive rats were treated with the autoblood clot. Administration of heparin (2 mg/ml) before autoblood treatment had a protective effect on ionotropic glutamatergic and GABAergic receptors, whose activity was inhibited by the blood.

Exploring the optimal operation time for patients with hypertensive intracerebral hemorrhage: tracking the expression and progress of cell apoptosis of prehematomal brain tissues.

BACKGROUND: Hypertensive intracerebral hemorrhage (HICH) is a severe disease with high morbidity and mortality. Timely removal of the hematoma through surgical procedures may effectively reduce secondary injuries. However, there has long been a debate over the proper timing of such surgery. In this study, we explored the optimal operation time for HICH patients by observing the pathological changes in perihematomal brain regions during different stages of onset. METHODS: Twenty-five specimens of brain tissue, obtained from perihematomal region of HICH patients in different phases, were subjected to haematoxylin-eosin (HE) staining, terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate nick-end labeling (TUNEL) staining and Caspase-3, matrix metalloproteinases-9 (MMP-9) immunohistochemical staining. The changing roles of necrosis and apoptosis and the expression of MMP-9 and Caspase-3 positive cells were all observed using image analysis. RESULTS: The obvious expression of TUNEL positive cells was recognized within 6 hours of ICH onset, reaching its peak between 6 hours and 24 hours in the early phase. RESULTS: were highly consistent with Caspase-3 and MMP-9 positive cell counts. Necrosis was found 6 hours after ICH onset and aggravated after 12 hours. CONCLUSIONS: In the early phase, apoptosis was seen as a major modality of injury in the brain tissue of the perihematomal region and was strongly correlated with the expression of MMP-9 and Caspase-3. The results of the present study suggest that an operation performed as soon as possible after ICH onset may be optimal for preserving the nervous system function.

[Neural apoptosis and apoptosis-related genes in intracerebral hemorrhage patients].

OBJECTIVE: To observe the neural apoptosis and expression of apoptosis-related genes in brain in order to elucidate the regulation mechanism in the perihematomal region of intracerebral hemorrhage (ICH) patients. METHODS: Specimens of perihematomal region in human brain were obtained from 29 patients undergoing surgical evacuation of an intracerebral hematoma. Specimens of brain tissue were collected from the corpses of 6 persons within 3 hours after the accidental death. Neural apoptosis was evaluated by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5' triphosphate nick end labeling (TUNEL) method and immunohistochemistry was used to detect the expression of Bcl-2, Bax, P53, and caspase-3 genes. RESULTS: The apoptosis rates of the ICH group was 4.10 +/- 0.28, significantly higher than that of the control group (0.57 +/- 0.43, P < 0.01). The expression rate of Bcl-2 the ICH group was 2.68 +/- 0.52, significantly higher than that of the control group (1.54 +/- 0.56, P < 0.01). The expression rate of Bax of the ICH group was 3.49 +/- 0.18, significantly higher than that of the control group (0.96 +/- 0.27, P < 0.01). The expression of P53 was 4.12 +/- 0.63, significantly higher than that of the control group (0.96 +/- 0.71, P < 0.01). The expression of caspase-3 of the ICH group was 3.50 +/- 0.25, significantly higher than that of the control group (0.74 +/- 0.73, P < 0.01). The expression levels of Bcl-2 and P53 were negatively correlated with the apoptosis rate (both P < 0.01), while the expression levels of Bax and caspase-3, and the Bax/Bcl-2 ratio were positively correlated with the apoptosis rate in perihematomal region of ICH patients (all P < 0.01). CONCLUSION: Apoptosis is involved in the delayed brain injury after ICH in human and is the main factor of delayed neural death. Some of the genes take part in the regulation of neural apoptosis: Bax and caspase-3 hasten the apoptosis while Bcl-2 and P53 restrain it.

ACE inhibition reduces activity of the plasminogen/plasmin and MMP systems in the brain of spontaneous hypertensive stroke-prone rats.

The spontaneously hypertensive stroke-prone rat (SHR-SP) is an experimental model of malignant hypertension which lead to secondary alterations of the extracellular matrix. Our aim was to determine ACE-inhibitor related changes of proteases involved in the reconstruction of the extracellular matrix in the brain. Twelve SHR-SP rats were randomized into two groups. Each group was treated with either an antihypertensive dose of ramipril or placebo for 6 months. Brain tissue plasminogen activator (t-PA) and urokinase (u-PA) were quantified by using casein-dependent plasminogen zymography, matrix metalloproteinase (MMP)-2 and MMP-9, by MMP-zymography, and tissue inhibitor of MMP (TIMP)-1 and -2, by reverse zymography. The amounts of u-PA, t-PA, and MMPs were significantly reduced in animals treated with ACE inhibitor. Plasminogen zymography showed a 39% reduction of u-PA in the basal ganglia (p < 0.0001); t-PA expression was reduced by 26% in the cortex and by 33% in the basal ganglia (p < 0.0001). MMP-2 expression was reduced by 15% in the cortex (p < 0.05) and by 10% in the basal ganglia (p < 0.05); MMP-9 expression significantly decreased by 37% in the cortex and by 25% in the basal ganglia (p < 0.0001 each). No differences were observed in the amount of TIMP-1 or TIMP-2. These findings provide new insights into the biochemical mechanisms underlying extracellular matrix proliferation and its modulation by ACE inhibitors. Therapeutic alterations that influence the proteolytic systems might prove important in the prevention of extracellular matrix accumulation and secondary microvascular vessel wall changes.