Potential Therapeutic Strategies for Intracranial Aneurysms Targeting Aneurysm Pathogenesis

Impact of the Transforming Growth Factor β (TGF-β) on Brain Aneurysm Formation and Development: A Literature Review

The mechanisms underlying the formation and rupture of intracranial aneurysms remain unclear. Rupture of the aneurysmal wall causes subarachnoid hemorrhage, with a mortality rate of 35-50%. Literature suggests that rupture is associated with the remodeling of the aneurysmal wall, including endothelial cell damage, smooth muscle cells (SMCs) proliferation, and inflammatory cell infiltration, particularly macrophages. Transforming growth factor β (TGF-β) is a multifunctional factor that plays a diverse role in cell growth and differentiation. It is crucial for strengthening vessel walls during angiogenesis and also regulates the proliferation of SMCs, indicating the potential involvement of TGF-β signaling in the pathogenesis and development of cerebral aneurysms. This review examines the complex role of TGF-β, its receptors, and signaling pathways in cerebral aneurysm formation and progression. Understanding the molecular mechanisms of TGF-β signaling in aneurysm development is vital for identifying potential therapeutic targets to prevent aneurysm rupture. Further research is necessary to fully elucidate the role of TGF-β in aneurysm pathophysiology, which could lead to the development of novel therapeutic strategies for aneurysm prevention and management, particularly in preventing subarachnoid hemorrhage.

Bacterial DNA in patients with ruptured intracranial aneurysms: Investigating the potential role of periodontal and gut microbiota

BACKGROUND AND OBJECTIVES

Chronic periodontal bacterial infections and disruptions in gut microbiota are responsible for systemic inflammation, which may contribute to the rupture of intracranial aneurysm. This study aimed to assess the presence of bacterial DNA from Fusobacterium nucleatum and Escherichia coli within arterial tissues of intracranial aneurysms.

METHODOLOGY

A comprehensive cross-sectional study was conducted, applying stringent inclusion and exclusion criteria to carefully select the study population from patients admitted to the Division of Neurosurgery at Hospital das Clínicas, University of São Paulo. Samples were collected post-aneurysm microsurgical clipping, preserving their integrity for subsequent DNA extraction. Polymerase chain reaction (PCR) techniques were employed to identify bacterial DNA within these samples.

RESULTS

In total, 36 patient samples underwent a detailed analysis. The presence of Escherichia coli DNA exhibited a statistically significant correlation with the occurrence of ruptured intracranial aneurysms (Qualitative Odds Ratio [OR] 4.3 [1.01 - 23.4] and Quantitative OR 0.99 [0.99-1.0], Student's t-test [P = 0.9]). However, the presence of Fusobacterium nucleatum DNA did not demonstrate a statistically significant correlation with ruptured intracranial aneurysms (Qualitative OR 1.52 [0.4-6.1] and Quantitative OR 0.04 [0.01-5.22 ×108], Student's t-test [P = 0.78]).

CONCLUSION

The identification of Escherichia coli bacterial DNA in arterial tissues was positively associated with the occurrence of ruptured intracranial aneurysms, suggesting a potential role for these microorganisms in aneurysm pathogenesis and rupture. The development of therapeutic and prophylactic strategies can be established through future research endeavors.

Role of inflammatory mediators in intracranial aneurysms: A review

The formation, growth, and rupture of intracranial aneurysms (IAs) involve hemodynamics, blood pressure, external stimuli, and a series of hormonal changes. In addition, inflammatory response causes the release of a series of inflammatory mediators, such as IL, TNF-α, MCP-1, and MMPs, which directly or indirectly promote the development process of IA. However, the specific role of these inflammatory mediators in the pathophysiological process of IA remains unclear. Recently, several anti-inflammatory, lipid-lowering, hormone-regulating drugs have been found to have a potentially protective effect on reducing IA formation and rupture in the population. These therapeutic mechanisms have not been fully elucidated, but we can look for potential therapeutic targets that may interfere with the formation and breakdown of IA by studying the relevant inflammatory response and the mechanism of IA formation and rupture involved in inflammatory mediators.

Pharmaceutical Modulation of Intracranial Aneurysm Development and Rupture

Management of intracranial aneurysms (IAs) is determined by patient age, risk of rupture, and comorbid conditions. While endovascular and microsurgical interventions offer solutions to mitigate the risk of rupture, pharmacological management strategies may complement these approaches or serve as alternatives in appropriate cases. The pathophysiology of IAs allows for the targeting of inflammation to prevent the development and rupture of IAs. The aim of this review is to provide an updated summary of different pharmaceutical management strategies for IAs. Acetylsalicylic acid and renin-angiotensin-aldosterone system (RAAS) inhibitor antihypertensives have some evidence supporting their protective effect. Studies of selective cyclooxygenase-2 (COX-2) inhibitors, statins, ADP inhibitors, and other metabolism-affecting drugs have demonstrated inconclusive findings regarding their association with aneurysm growth or rupture. In this manuscript, we highlight the evidence supporting each drug's effectiveness.

Aspirin treatment for unruptured intracranial aneurysms: Focusing on its anti-inflammatory role

Intracranial aneurysms (IAs), as a common cerebrovascular disease, claims a worldwide morbidity rate of 3.2%. Inflammation, pivotal in the pathogenesis of IAs, influences their formation, growth, and rupture. This review investigates aspirin's modulation of inflammatory pathways within this context. With IAs carrying significant morbidity and mortality upon IAs rupture and current interventions limited to surgical clipping and endovascular coiling, the quest for pharmacological options is imperative. Aspirin's role in cardiovascular prevention, due to its anti-inflammatory effects, presents a potential therapeutic avenue for IAs. In this review, we examine aspirin's efficacy in experimental models and clinical settings, highlighting its impact on the progression and rupture risks of unruptured IAs. The underlying mechanisms of aspirin's impact on IAs are explored, with its ability examined to attenuate endothelial dysfunction and vascular injury. This review may provide a theoretical basis for the use of aspirin, suggesting a promising strategy for IAs management. However, the optimal dosing, safety, and long-term efficacy remain to be established. The implications of aspirin therapy are significant in light of current surgical and endovascular treatments. Further research is encouraged to refine aspirin's clinical application in the management of unruptured IAs, with the ultimate aim of reducing the incidence of aneurysms rupture.

ADORA3: A Key Player in the Pathogenesis of Intracranial Aneurysms and a Potential Diagnostic Biomarker

BACKGROUND

The effects of genes on the development of intracranial aneurysms (IAs) remain to be elucidated, and reliable blood biomarkers for diagnosing IAs are yet to be established. This study aimed to identify genes associated with IAs pathogenesis and explore their diagnostic value by analyzing IAs datasets, conducting vascular smooth muscle cells (VSMC) experiments, and performing blood detection.

METHODS

IAs datasets were collected and the differentially expressed genes were analyzed. The selected genes were validated in external datasets. Autophagy was induced in VSMC and the effect of selected genes was determined. The diagnostic value of selected gene on the IAs were explored using area under curve (AUC) analysis using IAs plasma samples.

RESULTS

Analysis of 61 samples (32 controls and 29 IAs tissues) revealed a significant increase in expression of ADORA3 compared with normal tissues using empirical Bayes methods of "limma" package; this was further validated by two external datasets. Additionally, induction of autophagy in VSMC lead to upregulation of ADORA3. Conversely, silencing ADORA3 suppressed VSMC proliferation and autophagy. Furthermore, analysis of an IAs blood sample dataset and clinical plasma samples demonstrated increased ADORA3 expression in patients with IA compared with normal subjects. The diagnostic value of blood ADORA3 expression in IAs was moderate when analyzing clinical samples (AUC: 0.756). Combining ADORA3 with IL2RB or CCR7 further enhanced the diagnostic ability for IAs, with the AUC value over 0.83.

CONCLUSIONS

High expression of ADORA3 is associated with IAs pathogenesis, likely through its promotion of VSMC autophagy. Furthermore, blood ADORA3 levels have the potential to serve as an auxiliary diagnostic biomarker for IAs.

Identification of Genes and miRNAs Associated with TAFI-Related Thrombosis: An in Silico Study

Thrombin-Activatable Fibrinolysis Inhibitor (TAFI) is a carboxypeptidase B-like proenzyme encoded by the CPB2 gene. After thrombin activation, TAFI downregulates fibrinolysis, thus linking the latter with coagulation. TAFI has been shown to play a role in venous and arterial thrombotic diseases, yet, data regarding the molecular mechanisms underlying its function have been conflicting. In this study, we focused on the prediction and functional enrichment analysis (FEA) of the TAFI interaction network and the microRNAs (miRNAs) targeting the members of this network in an attempt to identify novel components and pathways of TAFI-related thrombosis. To this end, we used nine bioinformatics software tools. We found that the TAFI interactome consists of 28 unique genes mainly involved in hemostasis. Twenty-four miRNAs were predicted to target these genes. Co-annotation analysis of the predicted interactors with respect to Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways and transcription factors (TFs) pointed to the complement and coagulation cascades as well as neutrophil extracellular trap formation. Cancer, stroke, and intracranial aneurysm were among the top 20 significant diseases related to the identified miRNAs. We reason that the predicted biomolecules should be further studied in the context of TAFI-related thrombosis.

Interruption of TRPC6-NFATC1 signaling inhibits NADPH oxidase 4 and VSMCs phenotypic switch in intracranial aneurysm

Intracranial aneurysm (IA) is a frequent cerebrovascular disorder with unclear pathogenesis. The vascular smooth muscle cells (VSMCs) phenotypic switch is essential for IA formation. It has been reported that Ca2+ overload and excessive reactive oxygen species (ROS) are involved in VSMCs phenotypic switch. The transient receptor potential canonical 6 (TRPC6) and NADPH oxidase 4 (NOX4) are the main pathway to participate in Ca2+ overload and ROS production in VSMCs. Ca2+ overload can activate calcineurin (CN), leading to nuclear factor of activated T cell (NFAT) dephosphorylation to regulate the target gene's transcription. We hypothesized that activation of TRPC6-NFATC1 signaling may upregulate NOX4 and involve in VSMCs phenotypic switch contributing to the progression of IA. Our results showed that the expressions of NOX4, p22phox, p47phox, TRPC6, CN and NFATC1 were significantly increased, and VSMCs underwent a significant phenotypic switch in IA tissue and cellular specimens. The VIVIT (NFATC1 inhibitor) and BI-749327 (TRPC6 inhibitor) treatment reduced the expressions of NOX4, p22phox and p47phox and the production of ROS, and significantly improved VSMCs phenotypic switch in IA rats and cells. Consistent results were obtained from IA Trpc6 knockout (Trpc6-/-) mice. Furthermore, the results also revealed that NFATC1 could regulate NOX4 transcription by binding to its promoter. Our findings reveal that interrupting the TRPC6-NFATC1 signaling inhibits NOX4 and improves VSMCs phenotypic switch in IA, and regulating Ca2+ homeostasis may be an important therapeutic strategy for IA.

Phoenixin-14 alleviates inflammatory smooth muscle cell-induced endothelial cell dysfunction in vitro

BACKGROUND

Intracranial aneurysm (IA) is cerebrovascular disorder which refers to local vessel wall damage to intracranial arteries, forming abnormal bulge. Both endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) are closely associated with IA formation and rupture. Inflammatory SMCs (iSMCs) were reported to induce EC dysfunction and result in IA progression. Phoenixin-14 (PNX-14) is a recently discovered brain peptide with pleiotropic roles, which participates in reproduction, cardio protection, lipid deposition and blood glucose metabolism. PNX-14 was previously reported to protect brain endothelial cells against oxygen-glucose deprivation/reoxygenation (OGD/R)-induced cell injury. Therefore, our study was designed to investigate the influence of PNX-14 on iSMCs-induced endothelial dysfunction.

METHODS

Inflammation in SMCs was induced by cyclic mechanical stretch. Human umbilical vein endothelial cells (HUVECs) were exposed to SMC- or iSMC-conditioned medium and then treated with 100 nM PNX-14 for 24 h. The levels of proinflammatory cytokines (IL-1β, IL-6 and TNF-α) in cell supernatants were analyzed by ELISA. Cell viability, apoptosis, angiogenesis and migration were subjected to CCK-8 assay, flow cytometry analysis, tube formation assay and Transwell migration assay. The protein levels of proinflammatory cytokines and apoptosis markers (Bcl-2 and Bax) were evaluated by western blotting.

RESULTS

Cyclic mechanical stretch upregulated IL-1β, IL-6 and TNF-α levels in SMCs. Treatment with SMC- or iSMC-conditioned medium HUVECs inhibited cell viability, angiogenesis and migration and induced apoptosis in HUVECs. iSMC-conditioned medium has more significant effects on cell functions. However, the influence of SMC- or iSMC-conditioned medium treatment on HUVEC biological functions were reversed by PNX-14 treatment. PNX-14 exerts no significant influence on the biological functions of HUVECs treated with SMC medium.

CONCLUSION

PNX-14 alleviates iSMCs-induced endothelial cell dysfunction in vitro.

Therapeutic Approaches for Cerebrovascular Dysfunction After Aneurysmal Subarachnoid Hemorrhage: An Update and Future Perspectives

Aneurysmal subarachnoid hemorrhage (aSAH) is a severe subtype of stroke occurring at a relatively young age with a significant socioeconomic impact. Treatment of aSAH includes early aneurysm exclusion, intensive care management, and prevention of complications. Once the aneurysm rupture occurs, blood spreading within the subarachnoid space triggers several molecular pathways causing early brain injury and delayed cerebral ischemia. Pathophysiologic mechanisms underlying brain injury after aSAH are not entirely characterized, reflecting the difficulties in identifying effective therapeutic targets for patients with aSAH. Although the improvements of the last decades in perioperative management, early diagnosis, aneurysm exclusion techniques, and medical treatments have increased survival, vasospasm and delayed cerebral infarction are associated with high mortality and morbidity. Clinical practice can rely on a few specific therapeutic agents, such as nimodipine, a calcium-channel blocker proved to reduce severe neurologic deficits in these patients. Therefore, new pharmacologic approaches are needed to improve the outcome of this life-threatening condition, as well as a tailored rehabilitation plan to maintain the quality of life in aSAH survivors. Several clinical trials are investigating the efficacy and safety of emerging drugs, such as magnesium, clazosentan, cilostazol, interleukin 1 receptor antagonists, deferoxamine, erythropoietin, and nicardipine, and continuous lumbar drainage in the setting of aSAH. This narrative review focuses on the most promising therapeutic interventions after aSAH.

Pharmacological inhibition of epidermal growth factor receptor attenuates intracranial aneurysm formation by modulating the phenotype of vascular smooth muscle cells

AIM

To study the effect of pharmacological inhibition of epidermal growth factor receptor (EGFR) on intracranial aneurysm (IA) initiation.

METHODS

Human IA samples were analyzed for the expression of p-EGFR and alpha smooth muscle actin (α-SMA) by immunofluorescence (IF). Rat models of IA were established to evaluate the ability of the EGFR inhibitor, erlotinib, to attenuate the incidence of IA. We analyzed anterior cerebral artery tissues by pathological and proteomic detection for the expression of p-EGFR and relevant proteins, and vessel casting was used to evaluate the incidence of aneurysms in each group. Rat vascular smooth muscle cells (VSMCs) and endothelial cells were extracted and used to establish an in vitro co-culture model in a flow chamber with or without erlotinib treatment. We determined p-EGFR and relevant protein expression in VSMCs by immunoblotting analysis.

RESULTS

Epidermal growth factor receptor activation was found in human IA vessel walls and rat anterior cerebral artery walls. Treatment with erlotinib markedly attenuated the incidence of IA by inhibiting vascular remodeling and pro-inflammatory transformation of VSMC in rat IA vessel walls. Activation of EGFR in rat VSMCs and phenotypic modulation of rat VSMCs were correlated with the strength of shear stress in vitro, and treatment with erlotinib reduced phenotypic modulation of rat VSMCs. In vitro experiments also revealed that EGFR activation could be induced by TNF-α in human brain VSMCs.

CONCLUSIONS

These results suggest that EGFR plays a critical role in the initiation of IA and that the EGFR inhibitor erlotinib protects rats from IA initiation by regulating phenotypic modulation of VSMCs.

On the Potential Self-Amplification of Aneurysms Due to Tissue Degradation and Blood Flow Revealed From FSI Simulations

Tissue degradation plays a crucial role in the formation and rupture of aneurysms. Using numerical computer simulations, we study the combined effects of blood flow and tissue degradation on intra-aneurysm hemodynamics. Our computational analysis reveals that the degradation-induced changes of the time-averaged wall shear stress (TAWSS) and oscillatory shear index (OSI) within the aneurysm dome are inversely correlated. Importantly, their correlation is enhanced in the process of tissue degradation. Regions with a low TAWSS and a high OSI experience still lower TAWSS and higher OSI during degradation. Furthermore, we observed that degradation leads to an increase of the endothelial cell activation potential index, in particular, at places experiencing low wall shear stress. These findings are robust and occur for different geometries, degradation intensities, heart rates and pressures. We interpret these findings in the context of recent literature and argue that the degradation-induced hemodynamic changes may lead to a self-amplification of the flow-induced progressive damage of the aneurysmal wall.

Mesenchymal stem cells-derived exosomes modulate vascular endothelial injury via miR-144-5p/PTEN in intracranial aneurysm

Phosphatase and tensin homolog (PTEN) is known to be involved in the pathogenesis of intracranial aneurysm (IA). This study investigated the molecular mechanism of exosomal miR-144-5p (ex-miR-144-5p) and PTEN in IA. Ex-miR-144-5p expression was assessed in serum from individuals with ruptured intracranial aneurysm (RA) or unruptured intracranial aneurysm (UA), and healthy controls (HC). Vascular endothelial cells (VECs) were co-cultured with exosomes isolated from mesenchymal stem cells (MSCs) with transfection of miR-144-5p mimic or miR-144-5p inhibitor. IA rats were induced by combing systemic hypertension and intrathecal elastase injection. VECs were transfected with miR-144-5p mimic or inhibitor to verify the impacts of miR-144-5p on cell viability and proliferation. The connection between miR-144-5p and PTEN was verified by luciferase activity assay. Our data proved that ex-miR-144-5p was decreased in both UA and RA patients. MiR-144-5p overexpression in MSCs-derived exosome promoted VEC viability, inhibited VEC proliferation of VEs, and decreased the protein levels of matrix metalloproteinase-9 (MMP-9), proliferating cell nuclear antigen (PCNA) and osteopontin (OPN). IA rats injected with ex-miR-144-5p mimic showed significant luminal dilation, declined smooth muscle layers, and thinned vascular wall. Besides, inhibited cell apoptosis and decreased protein expressions were also observed. However, ex-miR-144-5p inhibitor had the opposite effects both in vivo and in vitro. We validated that miR-144-5p directly targeted PTEN. MiR-144-5p mimic increased cell viability and proliferation and reduced protein expressions, which could be blunted by PTEN overexpression. This study suggests that miR-144-5p elevates PTEN expression, thereby boosting apoptosis and attenuating viability of VECs in IA.

CircRNA DOCK1 Regulates miR-409-3p/MCL1 Axis to Modulate Proliferation and Apoptosis of Human Brain Vascular Smooth Muscle Cells

Background

Intracranial aneurysm is an abnormal expansion in the intracranial arteries, which is associated with growth and apoptosis of vascular smooth muscle cells. Circular RNAs (circRNAs) have implicated in the progression of intracranial aneurysms. The purpose of this paper is to study the function and mechanism of circRNA dedicator of cytokinesis 1 (circ_DOCK1) in regulating proliferation and apoptosis of human brain vascular smooth muscle cells (HBVSMCs).

Methods

HBVSMCs were exposed to hydrogen peroxide (H₂O₂). Cell proliferation and apoptosis were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) and flow cytometry, respectively. Circ_DOCK1, microRNA (miR)-409-3p, and myeloid cell leukemia sequence 1 (MCL1) levels were examined by quantitative reverse transcription polymerase chain reaction or western blotting. The target association was assessed by dual-luciferase reporter, RNA pull-down, and RNA immunoprecipitation assays.

Results

Exposure to H₂O₂ decreased proliferation and increased apoptosis of HBVSMCs. Circ_DOCK1 expression was reduced in H₂O₂-treated HBVSMCs. Circ_DOCK1 overexpression rescued H₂O₂-caused reduction of proliferation and PCNA expression and attenuated H₂O₂-induced apoptosis and expression of Bcl-2, Bax, and cleaved PARP. MiR-409-3p was targeted by circ_DOCK1 and upregulated in H₂O₂-treated HBVSMCs. MiR-409-3p upregulation mitigated the role of circ_DOCK1 in proliferation and apoptosis of H₂O₂-treated HBVSMCs. MCL1 was targeted via miR-409-3p and downregulated via H₂O₂ treatment. Circ_DOCK1 overexpression enhanced MCL1 expression via modulating miR-409-3p. MiR-409-3p knockdown weakened H₂O₂-induced proliferation reduction and apoptosis promotion via regulating MCL1.

Conclusion

Circ_DOCK1 overexpression mitigated H₂O₂-caused proliferation inhibition and apoptosis promotion in HBVSMCs by modulating miR-409-3p/MCL1 axis.

MiR-455-5p serves as a biomarker of atherosclerosis and inhibits vascular smooth muscle cell proliferation and migration

Background: This study discussed the clinical value and expression level of miR-455-5p in atherosclerosis (AS) patients. Meanwhile, its regulatory effect on the proliferation and migration of vascular smooth muscle cells (VSMCs) was further analyzed. Materials & methods: Clinical experiments were detected by quantitative real-time PCR and receiver operating characteristic. Cell experiments were detected by CCK-8, transwell and luciferase reporter gene assay. Results: miR-455-5p was low expressed in AS patients and had diagnostic value to distinguish AS patients from healthy controls. MiR-455-5p inhibited the proliferation and migration of VSMCs. SOCS3 was the target gene of miR-455-5p. Conclusion: MiR-455-5p may be used as a potential diagnostic biomarker for AS. MiR-455-5p may inhibit the proliferation and migration of VSMCs through targeting SOCS3.

The Role of Aspirin in the Management of Intracranial Aneurysms: A Systematic Review and Meta-Analyses

Objective: To evaluate the association between aspirin use and the risks of unruptured intracranial aneurysm (UIA) growth and aneurysmal subarachnoid hemorrhage (aSAH).

Methods: We searched PubMed and Scopus from inception to 1 September 2020. Studies evaluating the associations between aspirin prescription and the risk of UIA growth or the risk of aSAH were included. The study only included patients with intracranial aneurysms. We assessed the quality of included studies using the Newcastle-Ottawa scale. Random-effects meta-analysis was conducted to pool the estimates of effect size quantitatively. Sensitivity analyses using the leave-one-out strategy were performed to identify any potential source of heterogeneity.

Results: After a review of 2,226 citations, five cohort studies, two case-control studies, and one nested case-control study involving 8,898 participants were included. Pooled analyses showed that aspirin use, regardless of frequency and duration, was associated with a statistically significantly lower risk of UIA growth (OR 0.25, 95% CI 0.11–0.54; I² = 0.0%, p = 0.604) and aSAH (OR, 0.37, 95% CI, 0.23–0.58; I² = 79.3%, p = 0.001) in patients presented with intracranial aneurysms. The results did not significantly change in sensitivity analyses.

Conclusions: Summarizing available evidence in the literature, our findings indicate that aspirin use, regardless of frequency and duration, was associated with a statistically significantly lower risk of UIA growth and aSAH in patients with UIA. Well-designed and large-scale clinical trials are needed to help define the role of aspirin as a protective pharmaceutical for UIAs.

Protocatechuic acid attenuates cerebral aneurysm formation and progression by inhibiting TNF-alpha/Nrf-2/NF-kB-mediated inflammatory mechanisms in experimental rats

Our current research aims to examine whether protocatechuic acid (PCA) can be used as a therapeutic agent for the development of cerebral aneurysm (CA) and to elucidate the mechanisms behind this. We assessed the effects of PCA at 50 and 100 mg/kg on the activation of signaling pathways for tissue necrosis factor (TNF)-α/nuclear factor (NF)-κB/nuclear factor erythroid 2 (Nrf-2) on progression and development in an elastase-induced CA model, accompanied by a high-salt diet to induce hypertension. The expression of inflammatory cytokines, chemokines, tumor necrosis factor-α, interleukins (IL)-8, IL-17, IL-6, IL-1β, and matrix metalloproteinase (MMP)-2 and MMP-9 was analyzed by ELISA, western blot, and reverse transcriptase quantative polymerase chain reaction. The expression levels of antioxidant enzymes and translocation of Nrf-2 were also determined. The group treated with PCA demonstrated a significant (P < 0.05) decrease in the aneurysmal size in rats compared to the CA-induced group. We found that PCA treatment suppressed the invasion of macrophage and activation of TNF-α/NF-κB/Nrf-2 signaling pathways. There was a significant decrease (P < 0.05) in pro-inflammatory cytokine and chemokine levels in a dose-dependent manner. We found that PCA treatment exerts protective effects by suppressing the development and progression of CA through the inhibition of inflammatory responses in macrophages via TNF-α/NF-κB/Nrf-2 signaling pathways, thus demonstrating that PCA can act as a treatment for CA.

Relationship between total plasma homocysteine and the risk of aneurysms - a meta-analysis

Our meta-analysis focused on the relationship between homocysteine (Hcy) level and the incidence of aneurysms and looked at the relationship between smoking, hypertension and aneurysms. A systematic literature search of Pubmed, Web of Science, and Embase databases (up to March 31, 2020) resulted in the identification of 19 studies, including 2,629 aneurysm patients and 6,497 healthy participants. Combined analysis of the included studies showed that number of smoking, hypertension and hyperhomocysteinemia (HHcy) in aneurysm patients was higher than that in the control groups, and the total plasma Hcy level in aneurysm patients was also higher. These findings suggest that smoking, hypertension and HHcy may be risk factors for the development and progression of aneurysms. Although the heterogeneity of meta-analysis was significant, it was found that the heterogeneity might come from the difference between race and disease species through subgroup analysis. Large-scale randomized controlled studies of single species and single disease species are needed in the future to supplement the accuracy of the results.