Secreted protein acidic and rich in cysteine (SPARC) induces apoptosis of human brain vascular smooth muscle cells through regulating HK2 in intracranial aneurysm.

Background: Vascular smooth muscle cell (VSMC) dysfunction is one of the crucial pathologic processes in the development of intracranial aneurysm (IA). Secreted protein acidic and rich in cysteine (SPARC), a multifunctional glycoprotein, is overexpressed in many tumor, but its underlying mechanism in vascular disease has not been elucidated. The aim of this study is to evaluate the potential function of SPARC in IA generation and regulation of mitochondrial function in VSMC. Methods: Human brain vascular smooth muscle cells were treated with recombinant SPARC to detect apoptosis-related markers. The downstream targets affecting mitochondrial dysfunction after SPARC treatment were explored by transcriptome sequencing and bioinformatics analysis, and verified using by immunohistochemistry and western blot. Further in vitro experiments verified the role of downstream targets in regulating VSMC mitochondrial function. Results: Secreted protein acidic and rich in cysteine (SPARC) expression was associated with the risk of IA rupture. SPARC induces mitochondrial pathway apoptosis in human brain VSMC. We screened 40 differentially expressed genes related to mitochondrial function after SPARC treatment. Hexokinase 2 (HK2) was identified as a downstream target of mitochondrial pathway apoptosis in VSMC induced by SPARC. In addition, immunohistochemical results confirmed that the difference between SPARC and HK2 expression is located mainly in the smooth muscle layer of IA. Overexpression of HK2 reversed the SPARC-induced increase in apoptosis and mitochondrial damage in VSMC. Conclusion: Secreted protein acidic and rich in cysteine (SPARC) regulated mitochondrial function in VSMC and induced apoptosis through HK2, which plays an important role in the formation and rupture of IA. Targeting SPARC may be a novel strategy to delay the development of intracranial aneurysms.

Identifying pyroptosis- and inflammation-related genes in intracranial aneurysms based on bioinformatics analysis.

BACKGROUND: Intracranial aneurysm (IA) is the most common cerebrovascular disease, and subarachnoid hemorrhage caused by its rupture can seriously impede nerve function. Pyroptosis is an inflammatory mode of cell death whose underlying mechanisms involving the occurrence and rupture of IAs remain unclear. In this study, using bioinformatics analysis, we identified the potential pyroptosis-related genes (PRGs) and performed their inflammatory response mechanisms in IAs. METHODS: The mRNA expression matrix of the IA tissue was obtained from the Gene Expression Omnibus database, and 51 PRGs were obtained from previous articles collected from PubMed. The differentially expressed PRGs (DEPRGs) were performed using R software. Subsequently, we performed enrichment analysis, constructed a protein-protein interaction network, performed weighted gene coexpression network analysis (WGCNA) and external validation using another dataset, and identified a correlation between hub genes and immune cell infiltration. Finally, the expression and tissue distribution of these hub genes in IA tissues were detected using Western blotting and immunohistochemical (IHC) staining. RESULTS: In total, 12 DEPRGs associated with IA were identified in our analysis, which included 11 up-regulated and one down-regulated genes. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses revealed that the DEPRGs were mostly enriched in the NOD-like receptor signaling pathway, interleukin-1 beta production, and the inflammasome complex. Three hub genes, NLRP3, IL1B and IL18, were identified using Cytoscape software and the WGCNA correlation module, and external validation revealed statistically significant differences between the expression of these hub genes in the ruptured and unruptured aneurysm groups (p < 0.05). Furthermore, all AUC values were > 0.75. Immune cell infiltration analysis suggested that the hub genes are related to CD8 T cell, macrophages and mast cells. Finally, IHC staining revealed that the protein levels of these hub genes were higher in ruptured and unruptured IA tissues than in normal tissues (p < 0.05). CONCLUSION: The results of bioinformatics analysis showed that pyroptosis is closely related to the formation and rupture of IA, and identified three potential hub genes involved in the pyroptosis and infiltration ofcells. Our findings may improve the understanding of the mechanisms underlying pyroptosis in IA.

Inhibition of BACE1 attenuates microglia-induced neuroinflammation after intracerebral hemorrhage by suppressing STAT3 activation.

Hematoma-induced neuroinflammation is the cause of poor prognosis in intracerebral hemorrhage (ICH); therefore, promoting blood clearance and blocking overactivated inflammation are rational approaches for ICH treatment. ß-site amyloid precursor protein (APP) lyase-1 (BACE1) is a key molecule regulating the microglial phenotype transition in neurodegenerative diseases. Therefore, the aim of this study was to investigate the role of BACE1 in microglial phagocytosis and inflammatory features in ICH. Here, we demonstrated the unique advantages of targeting BACE1 in microglia using an autologous blood model and primary microglia hemoglobin stimulation. When BACE1 was inhibited early in ICH, fewer residual hematomas remained, consistent with an increase in genetic features that favor phagocytosis and anti-inflammation. In addition, inhibition of BACE1 enhanced the secretion of anti-inflammatory cytokines and substantially reduced the expression of proinflammatory genes, which was regulated by signal transduction and phosphorylation of activator of transcription 3 (STAT3). Further pharmacological inhibition of STAT3 phosphorylation effectively blocked the proinflammatory and weak phagocytic phenotype of microglia due to BACE1 induction. In summary, BACE1 is the critical molecule regulating the inflammatory and phagocytic phenotypes of microglia after ICH, and targeted inhibition of the BACE1/STAT3 pathway is an important strategy for the future treatment of ICH-induced neurological injury.

Microsurgical revascularization of a symptomatic proximal vertebral artery: pilot experiences from a single center.

Background: Vertebral artery stenosis and occlusion (VASO) is a high-risk factor for posterior circulation stroke. Post-stent restenosis and drug tolerance have facilitated the exploration of microsurgical vascular reconstruction. This study aims to evaluate the safety and efficacy of microsurgical reconstruction of the proximal VA. Methods: Twenty-nine patients (25 men, aged 63.2 years) who had symptoms of posterior circulation ischemia underwent microsurgical revascularization for proximal VASO were retrospectively included in this study. Procedural complications and clinical and angiographic outcomes were reviewed. Results: Twelve, three, and five patients underwent VA endarterectomy, artery transposition, or both, respectively; seven patients underwent vertebral endarterectomy plus stent implantation; and two patients failed surgery because of the difficult exposure of the VA and the occurrence of vascular dissection. The perioperative period-related complications included seven cases of Horner's syndrome, five cases of hoarseness, and one case of chylothorax. No cases of perioperative stroke or death were reported. The mean follow-up period was 28.4 (8-62 months). Most patients improved clinically; however, the vertebrobasilar ischemia symptoms did not decrease significantly in two patients during the follow-up. Moreover, follow-up imaging was performed in all the patients, and no signs of anastomotic stenosis were reported. Conclusion: Microsurgical reconstruction is an alternative option that can effectively treat refractory proximal VASO disease and in-stent stenosis, with a high rate of postoperative vascular recirculation. Prospective cohort studies with larger sample sizes must be conducted to validate the above conclusions.

Reconstructive endovascular treatment for basilar artery trunk aneurysms: complications and clinical and angiography outcomes.

BACKGROUND: Basilar artery trunk aneurysms (BTAs) are rare intracranial aneurysms. We aim to investigate the procedural complications and clinical and angiographic outcomes of BTAs treated with reconstructive endovascular treatment (EVT). METHODS: We retrospectively reviewed the data of 111 patients with BTAs who underwent reconstructive EVT during 2013-2022. The factors associated with procedural complications and clinical and angiographic outcomes were analyzed. RESULTS: The study included 81 men and 30 women (median age 60 years). Overall, 26 (23.4%) cases presented with subarachnoid hemorrhage and 85 (76.6%) presented with unruptured aneurysms. Periprocedural ischemic and hemorrhagic complications occurred in 29 (26.1%) and 4 (3.6%) cases, respectively. The rate of favorable clinical outcomes was 83.8% (92/111) and the mortality rate was 14.4% (16/111). Angiographic follow-up data were available for 77/95 (81.1%) survivors; 57 (74.0%) and 20 (26%) aneurysms exhibited complete and incomplete obliteration, respectively. Old age, high Hunt and Hess grades (IV-V), hemorrhagic complications, and increased aneurysm size were independent risk factors for unfavorable clinical outcomes (p<0.05). Increased aneurysm size and incomplete aneurysm occlusion on immediate angiography were independent risk factors for incomplete occlusion during follow-up (p<0.05). CONCLUSION: Reconstructive EVTs are a feasible and effective treatment for BTAs but are associated with a high risk of ischemic and hemorrhagic complications and a high mortality rate. Larger aneurysms may predict unfavorable clinical outcomes and aneurysm recurrence during follow-up. Hemorrhagic complications may predict unfavorable clinical outcomes, whereas immediate complete aneurysm occlusion may predict total occlusion during follow-up.