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Background: The management of patients with disorders of consciousness (DOC) presents substantial challenges in clinical practice. Deep brain stimulation (DBS) has emerged as a potential therapeutic approach, but the lack of standardized regulatory parameters for DBS in DOC hinders definitive conclusions. Objective: This comprehensive review aims to provide a detailed summary of the current issues concerning patient selection, target setting, and modulation parameters in clinical studies investigating the application of DBS for DOC patients. Methods: A meticulous systematic analysis of the literatures was conducted, encompassing articles published from 1968 to April 2023, retrieved from reputable databases (PubMed, Embase, Medline, and Web of Science). Results: The systematic analysis of 21 eligible articles, involving 146 patients with DOC resulting from acquired brain injury or other disorders, revealed significant insights. The most frequently targeted regions were the Centromedian‐parafascicular complex (CM‐pf) nuclei and central thalamus (CT), both recognized for their role in regulating consciousness. However, other targets have also been explored in different studies. The stimulation frequency was predominantly set at 25 or 100 Hz, with pulse width of 120 μs, and voltages ranged from 0 to 4 V. These parameters were customized based on individual patient responses and evaluations. The overall clinical efficacy rate in all included studies was 39.7%, indicating a positive effect of DBS in a subset of DOC patients. Nonetheless, the assessment methods, follow‐up durations, and outcome measures varied across studies, potentially contributing to the variability in reported efficacy rates. Conclusion: Despite the challenges arising from the lack of standardized parameters, DBS shows promising potential as a therapeutic option for patients with DOC. However, there still remains the need for standardized protocols and assessment methods, which are crucial to deepen the understanding and optimizing the therapeutic potential of DBS in this specific patient population. [ABSTRACT FROM AUTHOR]

At present, there is limited research on the mechanisms underlying moyamoya disease (MMD). Herein, we aimed to determine the role of glutamine in MMD pathogenesis, and 360 adult patients were prospectively enrolled. Human brain microvascular endothelial cells (HBMECs) were subjected to Integrin Subunit Beta 4 (ITGB4) overexpression or knockdown and atorvastatin. We assessed factors associated with various signaling pathways in the context of the endothelial‐to‐mesenchymal transition (EndMT), and the expression level of related proteins was validated in the superficial temporal arteries of patients. We found glutamine levels were positively associated with a greater risk of stroke (OR = 1.599, p = 0.022). After treatment with glutamine, HBMECs exhibited enhanced proliferation, migration, and EndMT, all reversed by ITGB4 knockdown. In ITGB4‐transfected HBMECs, the MAPK–ERK–TGF–β/BMP pathway was activated, with Smad4 knockdown reversing the EndMT. Furthermore, atorvastatin suppressed the EndMT by inhibiting Smad1/5 phosphorylation and promoting Smad4 ubiquitination in ITGB4‐transfected HBMECs. We also found the protein level of ITGB4 was upregulated in the superficial temporal arteries of patients with MMD. In conclusion, our study suggests that glutamine may be an independent risk factor for hemorrhage or infarction in patients with MMD and targeting ITGB4 could potentially be therapeutic approaches for MMD. [ABSTRACT FROM AUTHOR]

Background: Moyamoya disease (MMD) stands as a prominent cause of stroke among children and adolescents in East Asian populations. Although a growing body of evidence suggests that dysregulated inflammation and autoimmune responses might contribute to the development of MMD, a comprehensive and detailed understanding of the alterations in circulating immune cells associated with MMD remains elusive. Methods: In this study, we employed a combination of single‐cell RNA sequencing (scRNA‐seq), mass cytometry and RNA‐sequencing techniques to compare immune cell profiles in peripheral blood samples obtained from patients with MMD and age‐matched healthy controls. Results: Our investigation unveiled immune dysfunction in MMD patients, primarily characterized by perturbations in T‐cell (TC) subpopulations, including a reduction in effector TCs and an increase in regulatory TCs (Tregs). Additionally, we observed diminished natural killer cells and dendritic cells alongside heightened B cells and monocytes in MMD patients. Notably, within the MMD group, there was an augmented proportion of fragile Tregs, whereas the stable Treg fraction decreased. MMD was also linked to heightened immune activation, as evidenced by elevated expression levels of HLA‐DR and p‐STAT3. Conclusions: Our findings offer a comprehensive view of the circulating immune cell landscape in MMD patients. Immune dysregulation in patients with MMD was characterized by alterations in T‐cell populations, including a decrease in effector T‐cells and an increase in regulatory T‐cells (Tregs), suggest a potential role for disrupted circulating immunity in the aetiology of MMD. [ABSTRACT FROM AUTHOR]

This article provides an overview of a study on familial cerebral cavernous malformations (CCMs), which are abnormal blood vessels in the brain that can lead to bleeding. The study found that there are distinct differences in the natural course and genetic makeup of symptomatic intracerebral hemorrhage (ICH) lesions and dot-sized lesions in familial CCMs. ICH lesions have a higher incidence rate of hemorrhage events and harbor both CCM germline mutations and PIK3CA somatic mutations, while dot-sized lesions only have CCM germline mutations. The article also explores the role of the PI3K-VEGF pathway and the potential of a VEGF inhibitor called bevacizumab as a treatment for CCMs, although further research is needed to evaluate its safety and efficacy. [Extracted from the article]

Background: Moyamoya disease (MMD) is a rare and complex cerebrovascular disorder characterized by the progressive narrowing of the internal carotid arteries and the formation of compensatory collateral vessels. The etiology of MMD remains enigmatic, making diagnosis and management challenging. The MOYAOMICS project was initiated to investigate the molecular underpinnings of MMD and explore potential diagnostic and therapeutic strategies. Methods: The MOYAOMICS project employs a multidisciplinary approach, integrating various omics technologies, including genomics, transcriptomics, proteomics, and metabolomics, to comprehensively examine the molecular signatures associated with MMD pathogenesis. Additionally, we will investigate the potential influence of gut microbiota and brain-gut peptides on MMD development, assessing their suitability as targets for therapeutic strategies and dietary interventions. Radiomics, a specialized field in medical imaging, is utilized to analyze neuroimaging data for early detection and characterization of MMD-related brain changes. Deep learning algorithms are employed to differentiate MMD from other conditions, automating the diagnostic process. We also employ single-cellomics and mass cytometry to precisely study cellular heterogeneity in peripheral blood samples from MMD patients. Conclusions: The MOYAOMICS project represents a significant step toward comprehending MMD's molecular underpinnings. This multidisciplinary approach has the potential to revolutionize early diagnosis, patient stratification, and the development of targeted therapies for MMD. The identification of blood-based biomarkers and the integration of multiple omics data are critical for improving the clinical management of MMD and enhancing patient outcomes for this complex disease. [ABSTRACT FROM AUTHOR]

Neurological and psychiatric diseases can lead to motor, language, emotional disorder, and cognitive, hearing or visual impairment By decoding the intention of the brain in real time, the Brain–computer interface (BCI) can first assist in the diagnosis of diseases, and can also compensate for its damaged function by directly interacting with the environment; In addition, provide output signals in various forms, such as actual motion, tactile or visual feedback, to assist in rehabilitation training; Further intervention in brain disorders is achieved by close‐looped neural modulation. In this article, we envision the future BCI digital prescription system for patients with different functional disorders and discuss the key contents in the prescription the brain signals, coding and decoding protocols and interaction paradigms, and assistive technology. Then, we discuss the details that need to be specially included in the digital prescription for different intervention technologies. The third part summarizes previous examples of intervention, focusing on how to select appropriate interaction paradigms for patients with different functional impairments. For the last part, we discussed the indicators and influencing factors in evaluating the therapeutic effect of BCI as intervention. [ABSTRACT FROM AUTHOR]

Background: Systemic immune-inflammatory markers such as neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), lymphocyte-to-monocyte ratio (LMR) and systemic immune-inflammatory index (SII) are associated with the prognosis of many cardiovascular and neoplastic diseases. Moyamoya disease (MMD) is associated with inflammation, but the relationship between systemic immune-inflammatory markers between MMD is unclear. The aim of our study was to analyse the association between systemic immune-inflammatory markers and the risk of MMD and its subtypes. Methods: We consecutively recruited 360 patients with MMD and 89 healthy control subjects in a case-control study to calculate and analyse the association of systemic immune-inflammatory markers with the risk of MMD and its subtypes. Results: The risk of MMD increased with higher levels of NLR (OR 1.237, 95% CI [1.008, 1.520], p =.042). When NLR and SII were assessed as quartile-spaced subgroups, the third quartile grouping of NLR and SII had a higher risk of MMD than the first quartile grouping (NLR: OR 3.206, 95% CI [1.271, 8.088], p =.014; SII: OR 3.074,95% CI [1.232,7.672], p =.016). When NLR was combined with SII, the highest subgroup had a higher risk of MMD than the lowest subgroup (OR2.643, 95% CI [1.340, 5.212], p =.005). The risk of subtypes also increased with higher levels of NLR and SII. The association between the levels of NLR and SII with the staging of the Suzuki stage follows an inverted U-shape. The highest levels of NLR and SII were found in patients with MMD at Suzuki stages 3–4. Conclusion: The risk of MMD increases with elevated systemic immune-inflammatory markers. This study analysed the association of systemic immune-inflammatory markers with the risk of developing MMD and its subtypes, and identified novel inflammatory markers for MMD. Systemic immune-inflammatory markers such as neutrophil–lymphocyte ratio and systemic immune-inflammatory index were higher in moyamoya disease (MMD) patients than in normal people. Systemic immune-inflammatory markers may be an independent risk factor for the onset of MMD. Systemic immune-inflammatory markers were associated with the progression of MMD, and their levels showed an inverted U shape with imaging stages. [ABSTRACT FROM AUTHOR]

Objective: The role of methionine (Met) cycle in the pathogenesis and progression of cardiovascular and cerebrovascular diseases has been established, but its association with moyamoya disease (MMD) has rarely been studied. This study aimed to analyze the levels of Met cycle‐related metabolites and constructed a risk model to explore its association with the risk of MMD. Methods: In this prospective study, a total of 302 adult MMD patients and 88 age‐matched healthy individuals were consecutively recruited. The serum levels of Met cycle‐related metabolites were quantified by liquid chromatography‐mass spectrometry (LC–MS). Participants were randomly divided into training set and testing set at a ratio of 1:1. The training set was used to construct the risk score model by LASSO regression. The association between Met cycle‐related risk score and the risk of MMD was analyzed using logistic regression and assessed by ROC curves. The testing set was used for validation. Results: The levels of methionine sulfoxide and homocysteine were significantly increased, while the levels of betaine and choline were significantly decreased in MMD and its subtypes compared to healthy controls (p < 0.05 for all). The training set was used to construct the risk model and the risk score of each participant has been calculated. After adjusting for potential confounders, the risk score was independently associated with the risk of MMD and its subtypes (p < 0.05 for all). We then divided the participants into low‐risk and high‐risk groups, the high‐risk score was significantly associated with the risk of MMD and its subtypes (p < 0.05 for all). The risk scores were further assessed as tertiles, the highest tertile was significantly associated with a higher risk of MMD and its subtypes compared to the lowest (p < 0.05 for all). The results were validated in the testing set. Conclusion: This study has constructed and validated a risk model based on Met cycle‐related metabolites, which was independently associated with the risk of MMD and its subtypes. The findings provided a new perspective on the risk evaluation and prevention of MMD. [ABSTRACT FROM AUTHOR]

N-acetylneuraminic acid (Neu5Ac) is a functional metabolite and has been demonstrated to be a risk factor for cardiovascular diseases. It is not clear whether Neu5Ac is associated with a higher risk of cerebrovascular disorders, especially moyamoya disease (MMD). We sought to elucidate the association between serum Neu5Ac levels and MMD in a case–control study and to create a clinical risk model. In our study, we included 360 MMD patients and 89 matched healthy controls (HCs). We collected the participants' clinical characteristics, laboratory results, and serum Neu5Ac levels. Increased level of serum Neu5Ac was observed in the MMD patients (p = 0.001). After adjusting for traditional confounders, the risk of MMD (odds ratio [OR]: 1.395; 95% confidence interval [CI]: 1.141–1.706) increased with each increment in Neu5Ac level (per μmol/L). The area under the curve (AUC) values of the receiver operating characteristic (ROC) curves of the basic model plus Neu5Ac binary outcomes, Neu5Ac quartiles, and continuous Neu5Ac are 0.869, 0.863, and 0.873, respectively. Furthermore, including Neu5Ac in the model offers a substantial improvement in the risk reclassification and discrimination of MMD and its subtypes. A higher level of Neu5Ac was found to be associated with an increased risk of MMD and its clinical subtypes. [ABSTRACT FROM AUTHOR]

Objective: Glioma is the most prevalent and fatal intracranial malignant tumor. Extracellular matrix protein 2 (ECM2) has rarely been studied in gliomas. Therefore, we explored the role of ECM2 in lower-grade gliomas (LGGs). Methods: The RNA-seq and clinicopathology data were obtained from the TCGA database. The immunohistochemical (IHC) staining was used to verify the expression of ECM2. Functional enrichment analyses, immune-related analyses, drug sensitivity, and mutation profile analyses were further conducted. Cox regression and Kaplan–Meier curves were utilized for survival analyses, while four external datasets were used to validate the prognostic role of ECM2. Furthermore, qRT-PCR, CCK-8, wound healing, and transwell assays were performed to confirm the function of ECM2 in gliomas. Results: The study found a significant upregulation of ECM2 expression with increasing glioma grades and a significant association between ECM2 expression and tumor immune infiltration. Cox regression verified the prognostic role of ECM2 in LGG patients (HR = 1.656, 95%CI = 1.055–2.600, p = 0.028). High ECM2 expression was significantly associated with poor outcome (p < 0.001). Four external datasets validated its prognostic value. After the knockdown of ECM2, the functional experiments showed a significant decrease in proliferation, migration, and invasion in glioma cell lines. Conclusion: The study suggested the potential of ECM2 as a novel immune-associated prognostic biomarker and therapeutic target for glioma patients. [ABSTRACT FROM AUTHOR]

Aims: To explore the underlying mechanism by which low‐frequency KRAS mutations result in extensive EndMT occurrence. Methods: Exosomes derived from primarily cultured brain arteriovenous malformation (bAVMs) and human umbilical vein endothelial cells (HUVECs) transfected with KRASG12D, KRASWT, or KRASNC lentiviruses were isolated, and their effects on HUVECs were identified by western blotting and immunofluorescence staining. The expression levels of exosomal microRNAs (miRNAs) were evaluated by miRNA microarray, followed by functional experiments on miR‐3131 and detection of its downstream target, and miR‐3131 inhibitor in reversing the EndMT process induced by KRASG12D‐transfected HUVECs and bAVM endothelial cells (ECs) were explored. Results: Exosomes derived from KRASG12D bAVM ECs and KRASG12D‐transfected HUVECs promoted EndMT in HUVECs. MiR‐3131 levels were highest in the exosomes of KRASG12D‐transfected HUVECs, and HUVECs transfected with the miR‐3131 mimic acquired mesenchymal phenotypes. RNA‐seq and dual‐luciferase reporter assays revealed that PICK1 is the direct downstream target of miR‐3131. Exosomal miR‐3131 was highly expressed in KRASG12D bAVMexos compared with non‐KRAS‐mutant bAVMexos or HUVECexos. Finally, a miR‐3131 inhibitor reversed EndMT in HUVECs treated with exosomes or the supernatant of KRASG12D‐transfected HUVECs and KRASG12D bAVM ECs. Conclusion: Exosomal miR‐3131 promotes EndMT in KRAS‐mutant bAVMs, and miR‐3131 might be a potential biomarker and therapeutic target in KRASG12D‐mutant bAVMs. [ABSTRACT FROM AUTHOR]

Introduction: The treatment of patients with disorders of consciousness (DoC) remains a challenging issue, and spinal cord stimulation (SCS) has been reported to be a promising treatment for DoC in some studies. Aims: This study explores the efficiency of SCS in treating patients with DoC at different consciousness levels, including the vegetative state/unresponsive wakefulness syndrome (VS/UWS) and the minimally conscious state (MCS) and summarizes and analyzes the long‐term effect and related factors of SCS in patients with DoC. Results: An overall positive outcome was reached in 35 of 110 patients (31.8%). Among patients with positive outcomes, the MCS group improved 45.53% more than VS/UWS group, and this difference was statistically significant. In terms of the recommendation standard, positive outcomes occurred in 33 patients (94.3%) in the highly recommended group and 2 patients (5.7%) in the weakly recommended group (p < 0.001). After adjustment for potential covariables, young age (age ≤ 19 years old) (p = 0.045) and MCS (p < 0.001) were significantly correlated with positive outcome. A nomogram based on age, state of consciousness, and pathogeny showed good predictive performance, with a c‐index of 0.794. The Hosmer–Lemeshow goodness‐of‐fit test showed that the model was well calibrated (χ2 = 3.846, p = 0.871). Conclusions: SCS is one of the most feasible treatments for patients with DoC, especially for patients with MCS. Younger age is significantly associated with better outcomes and could therefore serve as a basis for preoperative screening. However, more evidence‐based randomized controlled trials are needed to confirm the efficacy of the treatment. [ABSTRACT FROM AUTHOR]

Background and Purposes: The risk factors of poor postoperative angiogenesis in moyamoya disease (MMD) patients remain unknown. We aimed to investigate the association between hyperhomocysteinemia (HHcy) and postoperative angiogenesis of adult patients with MMD. Methods: A total of 138 adult patients with MMD were prospectively recruited from July 1 to December 31, 2019. After excluding 10 patients accepting conservative therapy and 77 individuals without postoperative digital subtraction angiography (DSA), all 51 MMD patients were enrolled, and 28 patients received bilateral operations separately. Patients were grouped according to postoperative angiogenesis and HHcy presentation, respectively. Clinical data and laboratory examinations were compared. Potential risk factors were evaluated by univariate and multivariate logistic regression analysis. Nomogram was further performed. The biological functions of homocysteine (Hcy) were explored in vitro. Results: Comparing to the normal, patients with poor postoperative angiogenesis were higher in serum Hcy (p = 0.004), HHcy ratio (p = 0.011), creatinine (Cr) (p < 0.001), uric acid (UA) (p = 0.036), Triglyceride (p = 0.001), high-density lipoprotein cholesterol (HDL-C) (p = 0.001), low-density lipoprotein cholesterol (LDL-C) (p = 0.009), ApoA (p = 0.022), apolipoprotein B (ApoB) (p = 0.013). Furthermore, HHcy was more common in men (p = 0.003) than women. Logistic analysis results showed that Hcy (OR = 0.817, 95% CI = 0.707–0.944, p = 0.006) was an independent risk factor. HHcy and Cr were significantly associated with poor postoperative angiogenesis in MMD patients. Further, Hcy could inhibit the proliferation, migration, and tube formation of human brain microvascular endothelial cells (HBMECs), which can be reversed by vascular endothelial growth factor (VEGF). Conclusion: The HHcy was significantly correlated with poor postoperative angiogenesis in adult patients with MMD. Hcy significantly inhibits HBMECs proliferation, migration, and tube formation. Furthermore, VEGF could reverse the inhibition effect induced by Hcy. Lowering the level of Hcy may be beneficial for postoperative MMD patients. Focusing on the pathophysiology and mechanism of HHcy might help to guide postoperative clinical management. [ABSTRACT FROM AUTHOR]

Due to the extremely intrinsic heterogeneity among glioma patients, the outcomes of these patients are tremendously different. Therefore, the exploitation of novel biomarker classification of glioma is vitally important for deep insight into the essence and predicting the prognosis of glioma. We aim to analyze the correlation between TP73 mRNA expression, DNA methylated alteration and the prognosis of WHO grade II/III glioma, utilizing bioinformatics to evaluate its significance as a risk‐factor in predicting the prognosis of these glioma patients. The analysis found that TP73 expression was positively correlated with the grade of glioma, and showed a strong correlation with glioma molecular classification, which revealed significantly higher TP73 expression in IDH‐wildtype than in IDH‐mutant subtype of WHO grade II/III glioma. Cox regression analysis indicated that high expression of TP73 shared an independent high‐risk factor impacting the prognosis of WHO grade II/III glioma. We discovered 8 DNA promoter methylation sites with prognostic significance, which were negatively associated with TP73 expression, and positively associated with beneficial overall survival (OS) and progression‐free survival (PFS). Integrating with four independent glioma datasets, subsequent Meta‐analysis verified that low expression of TP73 was closely related to favorable OS, especially in IDH‐mutant subtype. Moreover, we found that 1p/19qCodel/TP73low subgroup shared the most favorable OS, 1p/19qNon−codel/TP73high subgroup suffered the worst OS. Meanwhile, the enrichment analysis of TP73‐related differential mRNAs demonstrated that TP73 aberration in WHO grade II/III glioma might be closely related to cell cycle and P53 signaling pathways. Finally, TP73 expression of 53 glioma specimens was measured by qRT‐PCR, which was consistent with the previous analytical result, and TP73 high‐expression subgroup suffered worse PFS than TP73 low‐expression subgroup. In summary, our funding supports that TP73 gene can perform as a reliable biomarker to evaluate the survival outcome of patients diagnosed with WHO grade II/III glioma. [ABSTRACT FROM AUTHOR]

Aim: The aim of this guideline is to present current and comprehensive recommendations for the management of brain arteriovenous malformations (bAVMs) located in eloquent areas. Methods: An extended literature search on MEDLINE was performed between Jan 1970 and May 2020. Eloquence-related literature was further screened and interpreted in different subcategories of this guideline. The writing group discussed narrative text and recommendations through group meetings and online video conferences. Recommendations followed the Applying Classification of Recommendations and Level of Evidence proposed by the American Heart Association/American Stroke Association. Prerelease review of the draft guideline was performed by four expert peer reviewers and by the members of Chinese Stroke Association. Results: In total, 809 out of 2,493 publications were identified to be related to eloquent structure or neurological functions of bAVMs. Three-hundred and forty-one publications were comprehensively interpreted and cited by this guideline. Evidence-based guidelines were presented for the clinical evaluation and treatment of bAVMs with eloquence involved. Topics focused on neuroanatomy of activated eloquent structure, functional neuroimaging, neurological assessment, indication, and recommendations of different therapeutic managements. Fifty-nine recommendations were summarized, including 20 in Class I, 30 in Class IIa, 9 in Class IIb, and 2 in Class III. Conclusions: The management of eloquent bAVMs remains challenging. With the evolutionary understanding of eloquent areas, the guideline highlights the assessment of eloquent bAVMs, and a strategy for decision-making in the management of eloquent bAVMs. [ABSTRACT FROM AUTHOR]

Object: Patients with aneurysmal subarachnoid hemorrhage (aSAH) have an increased incidence of cardiac events and short-term unfavorable neurological outcomes during the acute phase of bleeding. We studied whether troponin I elevation after ictus can predict future major adverse cardiac events (MACEs) and long-term neurological outcomes after 2 years. Methods: Consecutive aSAH patients within 3 days of bleeding were eligible for review from a prospective observational cohort (ClinicalTrials.gov Identifier: NCT04785976). Potential predictors of future MACEs and unfavorable long-term neurological outcomes were calculated by Cox and logistic regression analyses. Additional Kaplan–Meier curves were performed. Results: A total of 213 patients were enrolled with an average follow-up duration of 34.3 months. Individuals were divided into two groups: elevated cTnI group and unelevated cTnI group. By the last available follow-up, 20 patients had died, with an overall all-cause mortality rate of 9.4% and an annual all-cause mortality rate of 3.8%. Patients with elevated cTnI had a significantly higher risk of future MACEs (10.6 vs. 2.1%, p = 0.024, and 95% CI: 1.256–23.875) and unfavorable neurological outcomes at discharge, 3-month, 1-, 2-years, and last follow-up (p = 0.001, p < 0.001, p = 0.001, p < 0.001, and p < 0.001, respectively). In the Cox analysis for future MACE, elevated cTnI was the only independent predictor (HR = 5.980; 95% CI: 1.428–25.407, and p = 0.014). In the multivariable logistic analysis for unfavorable neurological outcomes, peak cTnI was significant (OR = 2.951; 95% CI: 1.376–6.323; p = 0.005). Kaplan–Meier analysis indicated that the elevated cTnI was correlated with future MACE (log-rank test, p = 0.007) and subsequent death (log-rank test, p = 0.004). Conclusion: cTnI elevation after aSAH could predict future MACEs and unfavorable neurological outcomes. [ABSTRACT FROM AUTHOR]

Growing evidence suggests that systemic immune and inflammatory responses may play a critical role in the formation and development of aneurysms. Exploring the differences between single intracranial aneurysm (SIA) and multiple IAs (MIAs) could provide insights for targeted therapies. However, there is a lack of comprehensive and detailed characterization of changes in circulating immune cells in MIAs. Peripheral blood mononuclear cell (PBMC) samples from patients with SIA (n = 16) or MIAs (n = 6) were analyzed using high-dimensional mass cytometry to evaluate the frequency and phenotype of immune cell subtypes. A total of 25 cell clusters were identified, revealing that the immune signature of MIAs included cluster changes. Compared to patients with SIA, patients with MIAs exhibited immune dysfunction and regulatory imbalance in T-cell clusters. They also had reduced numbers of CD8+ T cells and their subgroups CD8+ Te and CD8+ Tem cells, as well as reduced numbers of the CD4+ T-cell subgroup CD27-CD4+ Tem cells. Furthermore, compared to SIA, MIAs were associated with enhanced T-cell immune activation, with elevated expression levels of CD3, CD25, CD27, CCR7, GP130, and interleukin 10. This study provides insights into the circulating immune cell profiles in patients with MIAs, highlighting the similarities and differences between patients with SIA and those with MIAs. Furthermore, the study suggests that circulating immune dysfunction may contribute to development of MIAs., (© The Author(s) 2024. Published by Oxford University Press on behalf of the British Society for Immunology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Background: Disorders of consciousness (DoC) represent a spectrum of neurological conditions that pose significant treatment challenges. Percutaneous short-term spinal cord stimulation (SCS) has emerged as a promising experimental diagnostic treatment to assess and potentially improve consciousness levels. However, the effectiveness of this intervention is frequently compromised by the shift of electrodes, particularly in the cervical region, which can negatively affect therapeutic outcomes., Methods: This retrospective study aimed to study if electrodes shift in percutaneous short-term SCS in patients with DoC would affect the outcome. We analyzed the relationship between electrode shift length and patient outcome, as well as the correlation with various anatomical parameters, including the actual length of the cervical spine, linear length, spinal canal transverse diameter, spinal canal diameter, and C2 cone height, in a cohort of patients undergoing the procedure., Results: Our findings revealed that in patients with better outcome, there are significant less patient with electrode shift ( p  = 0.019). Further, a linear correlation was found between the length of electrode shift and patients' outcome (Rho = 0.583, p  = 0.002), with longer shift lengths associated with poorer outcomes. Contrary to our expectations, there was no significant association between the measured anatomical parameters and the extent of electrode shift. However, a trend was found between the actual length of the cervical spine and the shift of the electrode ( p  = 0.098). Notably, the shorter spinal canal transverse diameter was found to be significantly associated with better outcome in patients with DoC receiving percutaneous short-term SCS ( p  = 0.033)., Conclusion: These results highlight the clinical importance of electrode stability in the cervical region during SCS treatment for patients with DoC. Ensuring secure placement of electrodes may play a crucial role in enhancing patients' outcome and minimize postoperative complications. Given the lack of association with expected anatomical parameters, future research should investigate other factors that could impact electrode stability to optimize this therapeutic intervention., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 He, Yang, Xu, Niu, Wu, Huang, Chai, Cao, Wang, Wong, He, Yang and Zhao.)

A brain-computer interface (BCI) serves as a direct communication channel between brain activity and external devices, typically a computer or robotic limb. Advances in technology have led to the increasing use of intracranial electrical recording or stimulation in the treatment of conditions such as epilepsy, depression, and movement disorders. This indicates that BCIs can offer clinical neurological rehabilitation for patients with disabilities and functional impairments. They also provide a means to restore consciousness and functionality for patients with sequelae from major brain diseases. Whether invasive or non-invasive, the collected cortical or deep signals can be decoded and translated for communication. This review aims to provide an overview of the advantages of endovascular BCIs compared with conventional BCIs, along with insights into the specific anatomical regions under study. Given the rapid progress, we also provide updates on ongoing clinical trials and the prospects for current research involving endovascular electrodes., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background and Objectives: Initial shunt failure following ventriculoperitoneal (VP) shunt surgery has a significant impact on the working time of the shunt. However, there are few studies regarding factors affecting VP shunt longevity. Hence, in this study, we aimed to build a nomogram to predict the longevity of the replacement VP shunt in patients with initial shunt failure., Methods: From 2011 to 2021, 142 patients with initial VP failure who underwent VP shunt revision were enrolled and relevant clinical and demographic factors were analyzed. Univariate and multivariate Cox proportional hazard regression models were used to choose predictors, and a nomogram was constructed using nine independent prognostic variables: sex, age, hydrocephalus type, intensive care unit admission, tracheostomy, decompressive craniectomy, craniotomy, lumbar cisterna drainage, and ventricular drainage. The prediction models' discrimination, accuracy, calibration, and clinical value were evaluated using Harrell's C-index, a calibration plot, and decision curve analysis., Results: At 1 month, 3 months, and 5 years, the nomogram's C-index was 0.680, 0.708, and 0.694, respectively. The nomogram's calibration plot provided a good fit for the overall prediction over the course of 1 year. Decision curve analysis predicted that 1-3 months after surgery will yield good net benefits between 30 and 50% probability thresholds., Conclusion: A preoperative nomogram may be an effective tool for assessing VP shunt longevity after initial VP shunt placement., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Liu, He, Niu, Li, Geng, Cao, Wang, Lv, He, Zhao, Chen and Yang.)

Objective: Extra-axial cavernous hemangiomas (ECHs) are sporadic and rare intracranial occupational lesions that usually occur within the cavernous sinus. The aetiology of ECHs remains unknown., Methods: Whole-exome sequencing was performed on ECH lesions from 12 patients (discovery cohort) and droplet digital polymerase-chain-reaction (ddPCR) was used to confirm the identified mutation in 46 additional cases (validation cohort). Laser capture microdissection (LCM) was carried out to capture and characterise subgroups of tissue cells. Mechanistic and functional investigations were carried out in human umbilical vein endothelial cells and a newly established mouse model., Results: We detected somatic GJA4 mutation (c.121G>T, p.G41C) in 5/12 patients with ECH in the discovery cohort and confirmed the finding in the validation cohort (16/46). LCM followed by ddPCR revealed that the mutation was enriched in lesional endothelium. In vitro experiments in endothelial cells demonstrated that the GJA4 mutation activated SGK-1 signalling that in turn upregulated key genes involved in cell hyperproliferation and the loss of arterial specification. Compared with wild-type littermates, mice overexpressing the GJA4 mutation developed ECH-like pathological morphological characteristics (dilated venous lumen and elevated vascular density) in the retinal superficial vascular plexus at the postnatal 3 weeks, which were reversed by an SGK1 inhibitor, EMD638683., Conclusions: We identified a somatic GJA4 mutation that presents in over one-third of ECH lesions and proposed that ECHs are vascular malformations due to GJA4 -induced activation of the SGK1 signalling pathway in brain endothelial cells., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Deep brain stimulation (DBS) has been preliminarily applied to treat patients with disorders of consciousness (DoCs). The study aimed to determine whether DBS was effective for treating patients with DoC and identify factors related to patients' outcomes., Methods: Data from 365 patients with DoCs who were consecutively admitted from 15 July 2011 to 31 December 2021 were retrospectively analysed. Multivariate regression and subgroup analysis were performed to adjust for potential confounders. The primary outcome was improvement in consciousness at 1 year., Results: An overall improvement in consciousness at 1 year was achieved in 32.4% (12/37) of the DBS group compared with 4.3% (14/328) of the conservative group. After full adjustment, DBS significantly improved consciousness at 1 year (adjusted OR 11.90, 95% CI 3.65-38.46, p<0.001). There was a significant treatment×follow up interaction (H=14.99, p<0.001). DBS had significantly better effects in patients with minimally conscious state (MCS) compared with patients with vegetative state/unresponsive wakefulness syndrome (p for interaction <0.001). A nomogram based on age, state of consciousness, pathogeny and duration of DoCs indicated excellent predictive performance (c-index=0.882)., Conclusions: DBS was associated with better outcomes in patients with DoC, and the effect was likely to be significantly greater in patients with MCS. DBS should be cautiously evaluated by nomogram preoperatively, and randomised controlled trials are still needed., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objectives: The pathological mechanism for a disorder of consciousness (DoC) is still not fully understood. Based on traditional behavioral scales, there is a high rate of misdiagnosis for subtypes of DoC. We aimed to explore whether topological characterization may explain the pathological mechanisms of DoC and be effective in diagnosing the subtypes of DoC., Methods: Using resting-state functional magnetic resonance imaging data, the weighted brain functional networks for normal control subjects and patients with vegetative state (VS) and minimally conscious state (MCS) were constructed. Global and local network characteristics of each group were analyzed. A support vector machine was employed to identify MCS and VS patients., Results: The average connection strength was reduced in DoC patients and roughly equivalent in MCS and VS groups. Global efficiency, local efficiency, and clustering coefficients were reduced, and characteristic path length was increased in DoC patients ( p < 0.05). For patients of both groups, global network measures were not significantly different ( p > 0.05). Nodal efficiency, nodal local efficiency, and nodal clustering coefficient were reduced in frontoparietal brain areas, limbic structures, and occipital and temporal brain areas ( p < 0.05). The comparison of nodal centrality suggested that DoC causes reorganization of the network structure on a large scale, especially the thalamus. Lobal network measures emphasized that the differences between the two groups of patients mainly involved frontoparietal brain areas. The accuracy, sensitivity, and specificity of the classifier for identifying MCS and VS patients were 89.83, 78.95, and 95%, respectively., Conclusion: There is an association between altered network structures and clinical symptoms of DoC. With the help of network metrics, it is feasible to differentiate MCS and VS patients., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Yang, Dai, He, Wang, Chen, Geng, He and Duan.)

Objective: Somatic KRAS mutations have been identified in the majority of brain arteriovenous malformations (bAVMs), and subsequent in vivo experiments have confirmed that KRAS mutation in endothelial cells (ECs) causes AVMs in mouse and zebrafish models. Our previous study demonstrated that the KRAS G12D mutant independently induced the endothelial-mesenchymal transition (EndMT), which was reversed by treatment with the lipid-lowering drug lovastatin. However, the underlying mechanisms of action were unclear., Methods: We used human umbilical vein ECs (HUVECs) overexpressing the KRAS G12D mutant for Western blotting, quantitative real-time PCR, and immunofluorescence and wound healing assays to evaluate the EndMT and determine the activation of downstream pathways. Knockdown of SMAD4 by RNA interference was performed to explore the role of SMAD4 in regulating the EndMT. BAVM ECs expressing the KRAS G12D mutant were obtained to verify the SMAD4 function. Finally, we performed a coimmunoprecipitation assay to probe the mechanism by which lovastatin affects SMAD4., Results: HUVECs infected with KRAS G12D adenovirus underwent the EndMT. Transforming growth factor beta (TGF-β) and bone morphogenetic protein (BMP) signalling pathways were activated in the KRAS G12D -mutant HUVECs and ECs in bAVM tissue. Knocking down SMAD4 expression in both KRAS G12D -mutant HUVECs and ECs in bAVM tissues inhibited the EndMT. Lovastatin attenuated the EndMT by downregulating p-SMAD2/3, p-SMAD1/5 and acetylated SMAD4 expression in KRAS G12D -mutant HUVECs., Conclusions: Our findings suggest that the KRAS G12D mutant induces the EndMT by activating the ERK-TGF-β/BMP-SMAD4 signalling pathway and that lovastatin inhibits the EndMT by suppressing TGF-β/BMP pathway activation and SMAD4 acetylation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: Methionine sulfoxide (MetO) has been identified as a risk factor for vascular diseases and was considered as an important indicator of oxidative stress. However, the effects of MetO and its association with moyamoya disease (MMD) remained unclear. Therefore, we performed this study to evaluate the association between serum MetO levels and the risk of MMD and its subtypes., Methods: We eventually included consecutive 353 MMD patients and 88 healthy controls (HCs) with complete data from September 2020 to December 2021 in our analyzes. Serum levels of MetO were quantified using liquid chromatography-mass spectrometry (LC-MS) analysis. We evaluated the role of MetO in MMD using logistic regression models and confirmed by receiver-operating characteristic (ROC) curves and area under curve (AUC) values., Results: We found that the levels of MetO were significantly higher in MMD and its subtypes than in HCs ( p  < 0.001 for all). After adjusting for traditional risk factors, serum MetO levels were significantly associated with the risk of MMD and its subtypes (p < 0.001 for all). We further divided the MetO levels into low and high groups, and the high MetO level was significantly associated with the risk of MMD and its subtypes ( p  < 0.05 for all). When MetO levels were assessed as quartiles, we found that the third (Q3) and fourth (Q4) MetO quartiles had a significantly increased risk of MMD compared with the lowest quartile (Q3, OR: 2.323, 95%CI: 1.088-4.959, p  = 0.029; Q4, OR: 5.559, 95%CI: 2.088-14.805, p  = 0.001)., Conclusion: In this study, we found that a high level of serum MetO was associated with an increased risk of MMD and its subtypes. Our study raised a novel perspective on the pathogenesis of MMD and suggested potential therapeutic targets., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Li, Ge, He, Liu, Zeng, Tao, Zhai, Wang, Zhang, Wang, Zhang, Zhang and Zhao.)

Introduction: Regardless of the degree of stenosis, vulnerable plaque is an important cause of ischemic stroke and thrombotic complications. The changes of the immune microenvironment within plaques seem to be an important factor affecting the characteristics of the plaque. However, the differences of immune microenvironment between stable and vulnerable plaques were remained unknown., Methods: In this study, RNA-sequencing was performed on superficial temporal arteries from 5 traumatic patients and plaques from 3 atherosclerotic patients to preliminary identify the key immune response processes in plaques. Mass cytometry (CyTOF) technology was used to explore differences in immune composition between 9 vulnerable plaques and 12 stable plaques. Finally, immunofluorescence technique was used to validate our findings in the previous analysis., Results: Our results showed that more CD86+CD68+ M1 pro-inflammatory macrophages were found in vulnerable plaques, while CD4+T memory cells were mainly found in stable plaques. In addition, a CD11c+ subset of CD4+T cells with higher IFN-r secretion was found within the vulnerable plaque. In two subsets of B cells, CD19+CD20-B cells in vulnerable plaques secreted more TNF-a and IL-6, while CD19-CD20+B cells expressed more PD-1 molecules., Conclusion: In conclusion, our study suggested that M1-like macrophages are the major cell subset affecting plaque stability, while functional B cells may also contribute to plaque stability., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2023 Ge, Li, Ya, Xu, Ma, He, Wang, Liu, Zhang, Zhang, Wang, Zhang and Zhao.)

Background: Spinal cord stimulation (SCS) is a promising treatment for patients with disorders of consciousness (DoC); however, the laboratory examinations and different electrodes (permanent #39286 vs. temporary percutaneous #3777, Medtronic, USA) that are associated with postoperative outcomes are unclear. The study aims to study the association between the change in postoperative cerebrospinal fluid (CSF) protein level and improvement in consciousness after SCS in DoC patients and to explore whether different electrodes were associated with elevated CSF protein levels., Materials and Methods: A total of 66 DoC patients who received SCS treatment from December 2019 to December 2021 were retrospectively analyzed. Patients were grouped according to their elevated CSF protein level. The clinical characteristics of the patients and SCS stimulation parameters were compared. The preoperative sagittal diameter of the spinal canal is the distance from the midpoint of the posterior border of the vertebral body to the midpoint of the posterior wall of the spinal canal at the level of the superior border of C3. The postoperative sagittal diameter of the spinal canal is the distance from the midpoint of the posterior edge of the vertebral body to the anterior edge of the stimulation electrode. Patients with improved postoperative CRS-R scores greater than 3 or who progressed to the MCS + /eMCS were classified as the improved group and otherwise regarded as poor outcome., Results: We found that more DoC patients had elevated CSF protein levels among those receiving SCS treatment with permanent electrodes than temporary percutaneous electrodes ( P = 0.001), and elevated CSF protein levels were significantly associated with a reduced sagittal diameter ( P = 0.044). In DoC patients receiving SCS treatment, we found that elevated CSF protein levels ( P = 0.022) and preoperative diagnosis ( P = 0.003) were significantly associated with poor outcomes at 3 months. Logistic regression analysis showed that elevated CSF protein levels were significantly associated with poor outcomes (OR 1.008, 95% CI 1.001-1.016, P = 0.032)., Conclusion: The results suggest that reducing the effect of electrode pads on anatomical changes may help improve the outcomes of DoC patients receiving SCS treatment. CSF protein levels are associated with poor postoperative outcomes and whether they are potential biomarkers in DoC patients receiving SCS treatment remain further exploration., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 He, Li, Xiong, Xia, Dang, Chen, Geng, He, Yang and Zhao.)

Objective: Branched-Chain Amino Acids (BCAAs) has been identified as a risk factor for circulatory disease. Nevertheless, the effects and mechanisms of BCAAs on the risk of moyamoya disease (MMD) remain unrecognized. Hence, we aimed to elucidate the association between circulating BCAAs and the risk of MMD and clinical subtypes., Methods: We conducted a case-control study of 360 adult MMD patients and 89 matched healthy controls consecutively recruited between September 2020 and December 2021. Serum level of BCAAs was quantified by liquid chromatography-mass spectrometry. The associations between BCAAs and risk of MMD were evaluated., Results: Increased level of serum BCAAs was observed in MMD patients ( P < 0.001). After adjusting for traditional confounders, the elevated BCAAs level was significantly associated with the risk of MMD (Q4 vs. Q1: odds ratio, 3.10 [95% CI, 1.29-7.50]). The risk of subtypes in MMD also increased with each increment in the quartiles of BCAAs. Furthermore, BCAAs offered substantial improvement in risk reclassification and discrimination for MMD and subtypes., Conclusion: Higher level of circulating BCAAs was associated with increased risk of MMD and clinical subtypes. This study will help to elucidate the pathogenesis of MMD, which may provide the support for facilitating the treatments and preventions., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Zeng, Ge, Liu, Yu, Zhai, Liu, He, Li, Liu, Wang, Ye, Zhang, Wang, Zhang, Zhao and Zhang.)

Background and Purpose: Spinal cord stimulation (SCS) has been reported to be a promising neuromodulation method for patients with disorders of consciousness (DOC). Our previous studies found that clinical characteristics of patients and SCS stimulation parameters could affect the therapeutic effects of SCS, while surgical-related factors remain unknown. Through the improvement of surgical procedures, most of the SCS electrodes are implanted in the middle, while a small number of electrodes have still deviated., Methods: A total of 137 patients received SCS treatment in our institutions from 1 January 2010 to 31 December 2020. Among them, 27 patients were found with electrode deviation and met the inclusion criteria. Patients were grouped according to whether the electrode deviation angle (EDA) is >30°, respectively. Clinical characteristics of patients and SCS stimulation parameters were compared. Potential related factors and outcomes were evaluated by Chi-square test or two-way repeated measures analysis., Results: Twenty seven patients receiving cervical SCS treatment were found to have electrode deviation postoperatively. Among them, 12 patients were classified into the more deviation group. No significant difference was found among age, sex, pathogeny, course of DOC, C2-C5 distance, spinal cord to spinal canal ratio at C2 level, and preoperative JFK Coma Recovery Scale-Revised (CRS-R) scores. We found that the electrode direction significantly deviated to the contralateral side in the lateral decubitus position ( P = 0.025). The maximum tolerant stimulation intensity in the less deviation group (1.70 ± 0.41) was significantly higher than that in the more deviation group (1.25 ± 0.34) ( P = 0.006). Under the strongest stimulation, less unilateral limb tremor ( P = 0.049) and paroxysmal sympathetic hyperactivity (PSH) episodes ( P = 0.030) were found. EDA had a significant effect on postoperative CRS-R in patients, and patients in the less deviation group had significantly higher postoperative CRS-R ( P < 0.01). There was also an interaction effect between EDA and postoperative time. With the prolonged postoperative time, the CRS-R improvement rate of patients with different EDA was different, and the CRS-R improved faster in patients with less EDA ( P < 0.05)., Conclusions: Electrode deviation will affect the outcome of patients receiving cervical SCS treatment. The intraoperative surgical position is associated with postoperative electrode deviation direction. The reduction of EDA under 30° can increase maximum tolerant stimulation intensity, reduce complications, and further improve patients' outcomes., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 He, Han, Xia, Dang, Chen, He and Yang.)

Background: To compare the clinical outcomes of hybrid microsurgery and embolization with multi-staged procedure for patients harboring brain arteriovenous malformations (bAVMs)., Methods: We retrospectively reviewed bAVM patients from a multicenter, prospectively collected database (NCT03774017) between June 2016 and June 2020. Patients were divided into single-staged hybrid operation (HO) group and multi-staged operation (MO) group according to the received treatment, in which microsurgeries were performed with embolization in a single setting or with multi-stage procedure, respectively. Cases were 1:1 matched between the two groups. Outcomes were compared between groups, which included neurological deficits (NDs), perioperative rupture, and proportion of complete resection. Variables associated with NDs were analyzed., Results: In total, 198 out of 544 cases were identified, including 120 in the HO group and 78 in the MO group. Sixty-six cases were matched in each group resulting in a total of 132 patients in this case-controlled study. Mean age was 29.2 years old, with 82 (62.1%) being male. No significant difference was observed in baseline demographics and clinical characteristics between the two groups. There were 7 ruptures occurred in the interval between embolization and microsurgery for MO group while none in the HO group (P=0.023). This yielded a rupture risk of 4.1% per year for the MO group. Duration of surgical resection was significantly reduced in HO group (P=0.001). Compared to MO, HO was more favorable to avoid short-term NDs (3.0% vs. 15.2%, P=0.021), but long-term outcomes were similar. The HO modality (OR, 0.110; 95% CI: 0.017-0.737; P=0.023) was confirmed as the protective factor for short-term NDs., Conclusions: HO is an effective setup to treat complex bAVMs with avoiding interval hemorrhage risk and reducing surgical risk. We also observed overall similar obliteration rate and resulting clinical outcomes between HO and MO., Competing Interests: Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://atm.amegroups.com/article/view/10.21037/atm-22-811/coif). All authors report that this study was supported by National Key Technologies Research and Development Program of China (2016YFC1301800), Beijing Science and Technology Supporting Plan (D161100003816005), Beijing Municipal Administration of Hospitals’ Mission Plan (SML20150501), Project of China Postdoctoral Science Foundation (2019M660921), and Science Foundation for Postdoctorate Research of Beijing (2017-ZZ-123). The authors have no other conflicts of interest to declare., (2022 Annals of Translational Medicine. All rights reserved.)

Due to the similarity of Brillouin optical time domain analyzer (BOTDA) signals, image denoising could be utilized to remove the noise. However, the performance can be much degraded due to inaccurate noise level estimation. By numerical and experimental study, we compare the noise level estimation of three different methods for BOTDA: calculating the standard deviation (STD) of the measurements, a filter-based estimation algorithm, and a patch-based estimation algorithm proposed in this paper, which selects weak textured patches of BOTDA signal and then estimates noise level using principal component analysis (W-PCA). The results show that W-PCA and the mean of STD can accurately estimate the noise level, while the filter-based method overestimates the noise level. Nevertheless, for BOTDA with distributed amplification, the STD has huge fluctuation along the length, while the W-PCA is relatively robust for its global consideration. Experimental results of an ultra-long-distance BOTDA prove that the non-local means denoising processing based on W-PCA effectively removes the noise of a sensing system without signal distortion.

In this paper, we investigate the benefits of introducing the active fiber into long-distance point-sensing system based on random fiber laser (RFL). In this scheme the active fiber is placed between two segments of single mode fiber (SMF) and backward RFL pumping scheme is used. Through the numerical analysis, the influence of active fiber location on the spectral and power performance for the RFL is carefully discussed. Compared with the scheme without active fiber, the lasing threshold is much lower and the optical signal to noise ratio (OSNR) of the lasing line can be much higher, and the location of the active fiber has significant flexibility. The RFL experimental results are well coincident with the theoretical analysis; also, the sensing performance of such a system is demonstrated.