Transient Ischemic Attacks Preceding Ischemic Stroke and the Possible Preconditioning of the Human Brain: A Systematic Review and Meta-Analysis

The role of hypoxia/ischemia preconditioning in ischemic stroke

Ischemic stroke can cause damage to neurons, resulting in neurological dysfunction. The main treatments in the acute phase include intravenous thrombolysis, endovascular stent-assisted vascular thrombectomy and antiplatelet therapy. Due to the limitations of the time window and the risk of early intracranial hemorrhage, finding active treatment plans is crucial for improving therapy. Preconditioning can enhance the tolerance to acute injuries such as ischemic stroke and mechanical brain injury. This tolerance, induced by stressors like ischemia and hypoxia, can become an effective and convenient treatment approach for ischemic stroke. The molecular mechanisms involved in preconditioning are extremely complex. This article focuses on the main preconditioning treatment methods for ischemic stroke, discusses the specific molecular mechanisms of different treatment methods, and explores their action pathways and effects on corresponding target cells, thus opening up a brand-new direction for the treatment strategies of ischemic stroke.

Impact of Dual Antiplatelet Therapy Versus Monotherapy in Acute Stroke Management: A Systematic Review

This systematic review evaluates the comparative efficacy and safety of dual antiplatelet therapy (DAPT) versus monotherapy in the management of acute ischemic stroke and transient ischemic attack (TIA). Six studies, published between 2019 and 2024, were included, focusing on patient outcomes such as stroke recurrence, functional recovery, and safety measures. The findings consistently demonstrated that DAPT, particularly combinations like aspirin with clopidogrel or cilostazol, significantly reduced stroke recurrence and improved functional outcomes as compared to monotherapy, without a notable increase in major bleeding risk. Timing and duration of therapy were identified as critical factors, with early initiation and prolonged DAPT showing promising results in high-risk populations, including those with intracranial arterial stenosis or large artery atherosclerosis. Genetic polymorphisms, such as CYP2B6 variants, further influenced treatment efficacy, highlighting the potential for personalized therapeutic approaches. While the evidence underscores the clinical value of DAPT, it also identifies gaps such as the need for real-world studies and investigations into long-term safety. This review contributes to advancing stroke management by providing a nuanced, evidence-based perspective on the role of DAPT in reducing vascular events and disability.

Development and validation of a prognostic nomogram based on the hub genes of patients with hypertensive intracerebral hemorrhage

OBJECTIVE

Hypertensive intracerebral hemorrhage (HICH) is frequently associated with high disability, high mortality, and poor prognosis. The present study aimed to identify genes associated with HICH to construct prognostic models to improve accuracy in predicting HICH prognosis.

METHODS

Hub genes were identified by screening out differentially expressed genes from data in the Gene Expression Omnibus database and conducting weighted gene co-expression network analysis. 68 patients with HICH were recruited and categorized based on prognosis. The univariate logistic, least absolute shrinkage and selection operator, and multivariate logistic regression models were then established based on clinical data and the identified hub genes. A prognostic model was constructed based on the nomogram score. The model was validated using receiver operating characteristic curve, C-index, calibration plots, and decision curve analysis. It was also compared to a prognostic model constructed based on clinical data alone. The prognostic value of the nomogram score was assessed in different subgroups.

RESULTS

Three hub genes: pro-platelet basic protein (PPBP), PDZ and LIM domain protein 1 (PDLIM1), and metalloproteinase 1 (TIMP1) were identified as significantly correlated to adverse outcomes in HICH. These hub genes, in combination with the clinical data, were used to construct a nomogram score system, which exhibited strong predictive power, excellent consistency between actual outcomes and predictions, and a higher net clinical benefit. HICH patients with high scores presented significantly worse outcome. Importantly, the developed nomogram score system was superior to the use of clinicopathological features in predicting HICH prognosis. The nomogram score system exhibited adequate predictive performance in different subgroups as well.

CONCLUSION

The nomogram score system based on PPBP, PDLIM1, and TIMP1 genes, along with clinical data, exhibited superior performance in predicting adverse outcome in HICH patients. This system could, therefore, be useful for guiding clinical decisions and providing valuable insight for designing individualized treatments for HICH patients.

Research hotspots and frontiers of preconditioning in cerebral ischemia: A bibliometric analysis

Background

Preconditioning is a promising strategy against ischemic brain injury, and numerous studies in vitro and in vivo have demonstrated its neuroprotective effects. However, at present there is no bibliometric analysis of preconditioning in cerebral ischemia. Therefore, a comprehensive overview of the current status, hot spots, and emerging trends in this research field is necessary.

Materials and methods

Studies on preconditioning in cerebral ischemia from January 1999-December 2022 were retrieved from the Web of Science Core Collection (WOSCC) database. CiteSpace was used for data mining and visual analysis.

Results

A total of 1738 papers on preconditioning in cerebral ischemia were included in the study. The annual publications showed an upwards and then downwards trend but currently remain high in terms of annual publications. The US was the leading country, followed by China, the most active country in recent years. Capital Medical University published the largest number of articles. Perez-Pinzon, Miguel A contributed the most publications, while KITAGAWA K was the most cited author. The focus of the study covered three areas: (1) relevant diseases and experimental models, (2) types of preconditioning and stimuli, and (3) mechanisms of ischemic tolerance. Remote ischemic preconditioning, preconditioning of mesenchymal stem cells (MSCs), and inflammation are the frontiers of research in this field.

Conclusion

Our study provides a visual and scientific overview of research on preconditioning in cerebral ischemia, providing valuable information and new directions for researchers.

Acute ischemic stroke prediction and predictive factors analysis using hematological indicators in elderly hypertensives post-transient ischemic attack

Elderly hypertensive patients diagnosed with transient ischemic attack (TIA) are at a heightened risk for developing acute ischemic stroke (AIS). This underscores the critical need for effective risk prediction and identification of predictive factors. In our study, we utilized patient data from peripheral blood tests and clinical profiles within hospital information systems. These patients were followed for a three-year period to document incident AIS. Our cohort of 11,056 individuals was randomly divided into training, validation, and testing sets in a 5:2:3 ratio. We developed an XGBoost model, developed using selected indicators, provides an effective and non-invasive method for predicting the risk of AIS in elderly hypertensive patients diagnosed with TIA. Impressively, this model achieved a balanced accuracy of 0.9022, a recall of 0.8688, and a PR-AUC of 0.9315. Notably, our model effectively encapsulates essential data variations involving mixed nonlinear interactions, providing competitive performance against more complex models that incorporate a wider range of variables. Further, we conducted an in-depth analysis of the importance and sensitivity of each selected indicator and their interactions. This research equips clinicians with the necessary tools for more precise identification of high-risk individuals, thereby paving the way for more effective stroke prevention and management strategies.

Recurrent Transient Ischemic Attack Induces Neural Cytoskeleton Modification and Gliosis in an Experimental Model

Transient ischemic attack (TIA) presents a high risk for subsequent stroke, Alzheimer's disease (AD), and related dementia (ADRD). However, the neuropathophysiology of TIA has been rarely studied. By evaluating recurrent TIA-induced neuropathological changes, our study aimed to explore the potential mechanisms underlying the contribution of TIA to ADRD. In the current study, we established a recurrent TIA model by three times 10-min middle cerebral artery occlusion within a week in rat. Neither permanent neurological deficit nor apoptosis was observed following recurrent TIA. No increase of AD-related biomarkers was indicated after TIA, including increase of tau hyperphosphorylation and β-site APP cleaving enzyme 1 (BACE1). Neuronal cytoskeleton modification and neuroinflammation was found at 1, 3, and 7 days after recurrent TIA, evidenced by the reduction of microtubule-associated protein 2 (MAP2), elevation of neurofilament-light chain (NFL), and increase of glial fibrillary acidic protein (GFAP)-positive astrocytes and ionized calcium binding adaptor molecule 1 (Iba1)-positive microglia at the TIA-affected cerebral cortex and basal ganglion. Similar NFL, GFAP and Iba1 alteration was found in the white matter of corpus callosum. In summary, the current study demonstrated that recurrent TIA may trigger neuronal cytoskeleton change, astrogliosis, and microgliosis without induction of cell death at the acute and subacute stage. Our study indicates that TIA-induced neuronal cytoskeleton modification and neuroinflammation may be involved in the vascular contribution to cognitive impairment and dementia.

Intermittent Hypoxia Conditioning: A Potential Multi-Organ Protective Therapeutic Strategy

Severe hypoxia can induce a range of systemic disorders; however, surprising resilience can be obtained through sublethal adaptation to hypoxia, a process termed as hypoxic conditioning. A particular form of this strategy, known as intermittent hypoxia conditioning hormesis, alternates exposure to hypoxic and normoxic conditions, facilitating adaptation to reduced oxygen availability. This technique, originally employed in sports and high-altitude medicine, has shown promise in multiple pathologies when applied with calibrated mild to moderate hypoxia and appropriate hypoxic cycles. Recent studies have extensively investigated the protective role of intermittent hypoxia conditioning and its underlying mechanisms using animal models, demonstrating its potential in organ protection. This involves a range of processes such as reduction of oxidative stress, inflammation, and apoptosis, along with enhancement of hypoxic gene expression, among others. Given that intermittent hypoxia conditioning fosters beneficial physiological responses across multiple organs and systems, this review presents a comprehensive analysis of existing studies on intermittent hypoxia and its potential advantages in various organs. It aims to draw attention to the possibility of clinically applying intermittent hypoxia conditioning as a multi-organ protective strategy. This review comprehensively discusses the protective effects of intermittent hypoxia across multiple systems, outlines potential procedures for implementing intermittent hypoxia, and provides a brief overview of the potential protective mechanisms of intermittent hypoxia.

Aspiration thrombectomy versus stent retriever thrombectomy alone for acute ischemic stroke: evaluating the overlapping meta-analyses

BACKGROUND

Previous studies comparing a direct aspiration first pass technique (ADAPT) and stent retrievers have inconsistent methodologies and data reporting, limiting the ability to accurately assimilate data from different studies that would inform treatment of acute ischemic stroke (AIS) treatment.

OBJECTIVE

To conduct a systematic review to discuss and compare the findings of all relevant meta-analysis studies comparing the efficacy of the ADAPT and stent retriever techniques.

METHODS

The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), where meta-analyses comparing the efficacy of the ADAPT technique and stent retrievers in the treatment of AIS were included. We extracted all relevant data from the included studies and assessed the quality of the included meta-analyses using the Assessment of Multiple Systematic Review (AMSTAR-2).

RESULTS

Seven relevant studies met our inclusion criteria and were suitable for the qualitative synthesis. All included studies obtained data from randomized controlled trials (RCTs) and observational investigations (including levels II, III, and IV). At the same time, none of them used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) for quality assessment. In accordance with AMSTAR-2, two studies were rated 'high', while the other five were rated 'moderate'.

CONCLUSIONS

Present evidence is insufficient to clarify the superiority of one modality over the other. Further RCTs on this comparison must be conducted prior to designing further meta-analyses or making conclusive interpretations. Procedure duration and cost should be taken into consideration for any future studies.

The White Matter Functional Abnormalities in Patients with Transient Ischemic Attack: A Reinforcement Learning Approach

Background

Transient ischemic attack (TIA) is a known risk factor for stroke. Abnormal alterations in the low-frequency range of the gray matter (GM) of the brain have been studied in patients with TIA. However, whether there are abnormal neural activities in the low-frequency range of the white matter (WM) in patients with TIA remains unknown. The current study applied two resting-state metrics to explore functional abnormalities in the low-frequency range of WM in patients with TIA. Furthermore, a reinforcement learning method was used to investigate whether altered WM function could be a diagnostic indicator of TIA.

Methods

We enrolled 48 patients with TIA and 41 age- and sex-matched healthy controls (HCs). Resting-state functional magnetic resonance imaging (rs-fMRI) and clinical/physiological/biochemical data were collected from each participant. We compared the group differences between patients with TIA and HCs in the low-frequency range of WM using two resting-state metrics: amplitude of low-frequency fluctuation (ALFF) and fractional ALFF (fALFF). The altered ALFF and fALFF values were defined as features of the reinforcement learning method involving a Q-learning algorithm.

Results

Compared with HCs, patients with TIA showed decreased ALFF in the right cingulate gyrus/right superior longitudinal fasciculus/left superior corona radiata and decreased fALFF in the right cerebral peduncle/right cingulate gyrus/middle cerebellar peduncle. Based on these two rs-fMRI metrics, an optimal Q-learning model was obtained with an accuracy of 82.02%, sensitivity of 85.42%, specificity of 78.05%, precision of 82.00%, and area under the curve (AUC) of 0.87.

Conclusion

The present study revealed abnormal WM functional alterations in the low-frequency range in patients with TIA. These results support the role of WM functional neural activity as a potential neuromarker in classifying patients with TIA and offer novel insights into the underlying mechanisms in patients with TIA from the perspective of WM function.

Prevalence and In-hospital outcomes of diabetes among acute ischemic stroke patients in china: results from the Chinese Stroke Center Alliance

Background

Patients with ischemic stroke and diabetes are classified as extreme risk for secondary prevention, with much attention and specific management. However, the up-to-date information regarding the burden of diabetes in acute ischemic stroke (AIS) patients is lacking in China, and evidence for an association between diabetes and in-hospital outcomes after AIS remains controversial.

Methods

This quality improvement study was conducted at 1,476 participating hospitals in the Chinese Stroke Center Alliance between 2015 and 2019. Prevalence of diabetes was evaluated in the overall study population and different subgroups. The association between diabetes and in-hospital outcomes in AIS patients was analyzed by using multivariable logistic regression analysis and propensity score-matched analysis.

Results

Of 838,229 patients with AIS, 286,252 (34.2%) had diabetes/possible diabetes. The prevalence of diabetes/possible diabetes was higher in women than in men (37.6% versus 32.1%). Patients with diabetes/possible diabetes had higher rates of adverse in-hospital outcomes than those without. Multivariable analysis revealed a significant association between diabetes/possible diabetes and adverse in-hospital outcomes (all-cause mortality: odds ratio [OR], 1.30 [95% confidence interval [CI], 1.23–1.38]; major adverse cardiovascular events (MACEs): OR, 1.08 [95% CI, 1.06–1.10]) in AIS patients. The excess risk of in-hospital outcomes still remained in AIS patients with diabetes/possible diabetes after propensity score-matching analysis (all-cause mortality: OR, 1.26 [95% CI, 1.17–1.35]; MACEs: OR, 1.07 [95% CI, 1.05–1.10]).

Conclusion

Diabetes was highly prevalent among AIS patients in China and associated with worse in-hospital outcomes. Greater efforts to increase targeted approach to secondary prevention treatments of diabetes in AIS patients are warranted.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-022-11112-z.