The factors affecting neurogenesis after stroke and the role of acupuncture

Immediate and long-term brain activation of acupuncture on ischemic stroke patients: an ALE meta-analysis of fMRI studies

Background

Acupuncture, as an alternative and complementary therapy recommended by the World Health Organization for stroke treatment, holds potential in ameliorating neurofunctional deficits induced by ischemic stroke (IS). Understanding the immediate and long-term effects of acupuncture and their interrelation would contribute to a better comprehension of the mechanisms underlying acupuncture efficacy.

Methods

Activation likelihood estimation (ALE) meta-analysis was used to analyze the brain activation patterns reported in 21 relevant functional neuroimaging studies. Among these studies, 12 focused on the immediate brain activation and 9 on the long-term activation. Single dataset analysis were employed to identify both immediate and long-term brain activation of acupuncture treatment in IS patients, while contrast and conjunction analysis were utilized to explore distinctions and connections between the two.

Results

According to the ALE analysis, immediately after acupuncture treatment, IS patients exhibited an enhanced cluster centered around the right precuneus (PCUN) and a reduced cluster centered on the left middle frontal gyrus (MFG). After long-term acupuncture treatment, IS patients showed an enhanced cluster in the left PCUN, along with two reduced clusters in the right insula (INS) and hippocampus (HIP), respectively. Additionally, in comparison to long-term acupuncture treatment, the right angular gyrus (ANG) demonstrated higher ALE scores immediately after acupuncture, whereas long-term acupuncture resulted in higher scores in the left superior parietal gyrus (SPG). The intersecting cluster activated by both of them was located in the left cuneus (CUN).

Conclusion

The findings provide initial insights into both the immediate and long-term brain activation patterns of acupuncture treatment for IS, as well as the intricate interplay between them. Both immediate and long-term acupuncture treatments showed distinct patterns of brain activation, with the left CUN emerging as a crucial regulatory region in their association.

Systematic Review Registration

https://www.crd.york.ac.uk/prospero/, CRD42023480834.

Three-phase Enriched Environment Improves Post-stroke Gait Dysfunction via Facilitating Neuronal Plasticity in the Bilateral Sensorimotor Cortex: A Multimodal MRI/PET Analysis in Rats

The three-phase Enriched Environment (EE) paradigm has been shown to promote post-stroke functional improvement, but the neuronal mechanisms are still unclear. In this study, we applied a multimodal neuroimaging protocol combining magnetic resonance imaging (MRI) and positron emission tomography (PET) to examine the effects of post-ischemic EE treatment on structural and functional neuroplasticity in the bilateral sensorimotor cortex. Rats were subjected to permanent middle cerebral artery occlusion. The motor function of the rats was examined using the DigiGait test. MRI was applied to investigate the EE-induced structural modifications of the bilateral sensorimotor cortex. [18F]-fluorodeoxyglucose PET was used to detect glucose metabolism. Blood oxygen level-dependent (BOLD)-functional MRI (fMRI) was used to identify the regional brain activity and functional connectivity (FC). In addition, the expression of neuroplasticity-related signaling pathways including neurotrophic factors (BDNF/CREB), axonal guidance proteins (Robo1/Slit2), and axonal growth-inhibitory proteins (NogoA/NgR) as well as downstream proteins (RhoA/ROCK) in the bilateral sensorimotor cortex were measured by Western blots. Our results showed the three-phase EE improved the walking ability. Structural T2 mapping imaging and diffusion tensor imaging demonstrated that EE benefited structure integrity in the bilateral sensorimotor cortex. PET-MRI fused images showed improved glucose metabolism in the corresponding regions after EE intervention. Specifically, the BOLD-based amplitude of low-frequency fluctuations showed that EE increased spontaneous activity in the bilateral motor cortex and ipsilateral sensory cortex. In addition, FC results showed increased sensorimotor connectivity in the ipsilateral hemisphere and increased interhemispheric motor cortical connectivity and motor cortical-thalamic connectivity following EE intervention. In addition, a strong correlation was found between increased functional connectivity and improved motor performance of limbs. Specifically, EE regulated the expression of neuroplasticity-related signaling, involving BDNF/CREB, Slit2/Robo1, as well as the axonal growth-inhibitory pathways Nogo-A/Nogo receptor and RhoA/ROCK in the bilateral sensorimotor cortex. Our results indicated that the three-phase enriched environment paradigm enhances neuronal plasticity of the bilateral sensorimotor cortex and consequently ameliorates post-stroke gait deficits. These findings might provide some new clues for the development of EE and thus facilitate the clinical translation of EE.

Effectiveness of acupuncture in the governor vessel and Yangming meridian for the treatment of acute ischemic stroke: A systematic review and network meta-analysis

BACKGROUND

Acupuncture of the governor vessel and Yangming meridian are widely used in the treatment of acute ischemic stroke (AIS). However, the optimal meridian for acupuncture in the treatment of AIS remains uncertain.

PURPOSE

This network meta-analysis study aimed to compare the clinical effectiveness of acupuncture at governor vessel and Yangming meridian in the treatment of AIS.

METHODS

All relevant studies published in CNKI, WANFANG, VIP, Sinomed, Cochrane Library, Web of Science, Pub Med, and Embase before January 13, 2024 were systematically retrieved. The two researchers independently screened the studies and extracted the data. Cochrane ROB tool was used to evaluate the quality of the studies, and Stata 14.0 software was used to conduct a network meta-analysis of neurological deficit score, activities of daily living (ADL), clinical effective rate and Fugl-meyer motor function evaluation (FMA).

RESULTS

A total of 401 studies were obtained, and 17 studies met the inclusion criteria. The surface under the cumulative ranking curve (SUCRA) values of the four outcome indexes were all ranked by "Governor vessel acupuncture + Conventional neurology treatment(GVAc+CT) > Yangming meridian acupuncture + Conventional neurology treatment(YMAc+CT) > Conventional neurology treatment (CT)". Compared to YMAc+CT and CT, GVAc+CT had the best effect in reducing the degree of neurological deficit score (SMD = -0.72, 95%CI = [-1.22,-0.21] and SMD = -1.07,95%CI = [-1.45,-0.69], respectively) and promoting the recovery of ADL((SMD = 0.59,95%CI = [0.31,0.88] and SMD = 0.96,95%CI = [0.70,1.21], respectively). Compared to CT, GVAc+CT also had a better clinical effective rate in the treatment of AIS (RR = 1.14,95%CI = [1.04,1.25]).

CONCLUSIONS

Governor vessel acupuncture combined with conventional neurology treatment has the best effect in reducing the degree of neurological deficit score and promoting the recovery of ADL in AIS patientscompared to YMAc+CT and CT. Governor Vessel acupuncture is the most preferable acupoint scheme for clinical acupuncture treatment of AIS.

Acupuncture for post-stroke spasticity: An overview of systematic reviews

BACKGROUND

Post-stroke spasticity (PSS) is the most common complication of stroke. Acupuncture is widely used in clinical practice for the treatment of PSS, and is therefore considered a common complementary treatment. Several systematic reviews (SRs) and meta-analyses (MAs) have demonstrated the efficacy and safety of acupuncture in the treatment of PSS; however, the quality of evidence of these studies has not been adequately assessed.

OBJECTIVE

To evaluate and summarize the SRs/MAs and inform future research and clinical practice on the efficacy and safety of acupuncture for PSS.

DATA SOURCES AND EXTRACION

The following databases were searched from their dates of inception to March 26, 2023: PubMed, Embase, The Cochrane Library, Chinese National Knowledge Infrastructure (CNKI), Wanfang Database, SinoMed, and Chinese Science and Technology Periodical Database (VIP), and grey literature were manually searched. Two reviewers independently completed literature retrieval, screening, and data extraction.

REVIEW APPRAISAL

Systematic evaluation tools to Assess Systematic Reviews (AMSTAR) 2, Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020 Checklist), and the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system were used to systematically evaluate the methodological, reporting, and evidence quality of the SRs/MAs.

RESULTS

Overall, 226 papers were examined, and after careful consideration, 10 SRs/MAs were deemed eligible for inclusion. The AMSTAR 2 assessment revealed that one SR/MA had medium, one study had low, and the remaining eight studies had critically low methodological qualities. Additionally, four SRs/MAs completed more than 60 % of the PRISMA 2020 checklist. The GRADE system indicated that six outcomes were medium, 26 outcomes were low, and 24 outcomes were critically low.

CONCLUSION

Based on the evidence, acupuncture may be a promising complementary treatment to improve post-stroke spasticity and quality of life. Further high-quality RCTs are needed in future studies to support the broader application of acupuncture for the treatment of PSS.

Annexin A6 mitigates neurological deficit in ischemia/reperfusion injury by promoting synaptic plasticity

AIMS

Alleviating neurological dysfunction caused by acute ischemic stroke (AIS) remains intractable. Given Annexin A6 (ANXA6)'s potential in promoting axon branching and repairing cell membranes, the study aimed to explore ANXA6's potential in alleviating AIS-induced neurological dysfunction.

METHODS

A mouse middle cerebral artery occlusion model was established. Brain and plasma ANXA6 levels were detected at different timepoints post ischemia/reperfusion (I/R). We overexpressed and down-regulated brain ANXA6 and evaluated infarction volume, neurological function, and synaptic plasticity-related proteins post I/R. Plasma ANXA6 levels were measured in patients with AIS and healthy controls, investigating ANXA6 expression's clinical significance.

RESULTS

Brain ANXA6 levels initially decreased, gradually returning to normal post I/R; plasma ANXA6 levels showed an opposite trend. ANXA6 overexpression significantly decreased the modified neurological severity score (p = 0.0109) 1 day post I/R and the infarction area at 1 day (p = 0.0008) and 7 day (p = 0.0013) post I/R, and vice versa. ANXA6 positively influenced synaptic plasticity, upregulating synaptophysin (p = 0.006), myelin basic protein (p = 0.010), neuroligin (p = 0.078), and tropomyosin-related kinase B (p = 0.150). Plasma ANXA6 levels were higher in patients with AIS (1.969 [1.228-3.086]) compared to healthy controls (1.249 [0.757-2.226]) (p < 0.001), that served as an independent risk factor for poor AIS outcomes (2.120 [1.563-3.023], p < 0.001).

CONCLUSIONS

This study is the first to suggest that ANXA6 enhances synaptic plasticity and protects against transient cerebral ischemia.

Behavioral stress and antidepressant treatments altered hippocampal expression of Nogo signal-related proteins in rats

Some immune molecules including neurite outgrowth inhibitor (Nogo) ligands and their receptor（Nogo receptor-1: NgR1）are expressed at the neuronal synaptic sites. Paired immunoglobulin-like receptor B (PirB) is another Nogo receptor that also binds to major histocompatibility complex I and β-amyloid and suppresses dendritic immune cell functions and neuronal plasticity in the central nervous system. Augmenting structural and functional neural plasticity by manipulating the Nogo signaling pathway is a novel promising strategy for treating brain ischemia and degenerative processes such as Alzheimer's disease. In recent decades psychiatric research using experimental animals has focused on the attenuation of neural plasticity by stress loadings and on the enhanced resilience by psychopharmacological treatments. In the present study, we examined possible expressional alterations in Nogo signal-related proteins in the rat hippocampus after behavioral stress loadings and antidepressant treatments. To validate the effectiveness of the procedures, previously reported increase in brain-derived neurotrophic factor (BDNF) by ECS or ketamine administration and decrease of BDNF by stress loadings are also shown in the present study. Significant increases in hippocampal NgR1 and PirB expression were observed following chronic variable stress, and a significant increase in NgR1 expression was observed under a single prolonged stress paradigm. These results indicate a possible contribution of enhanced Nogo signaling to the attenuation of neural plasticity in response to stressful experiences. Additionally, the suppression of hippocampal NgR1 expression using electroconvulsive seizure treatment and administration of subanesthetic dose of ketamine supported the increased neural plasticity induced by the antidepressant treatments.

Aging-Related Protein Alterations in the Brain

Aging is an intrinsic aspect of an organism's life cycle and is characterized by progressive physiological decline and increased susceptibility to mortality. Many age-associated disorders, including neurological disorders, are most commonly linked with the aging process, such as Alzheimer's disease (AD). This review aims to provide a comprehensive overview of the effects of aging and AD on the molecular pathways and levels of different proteins in the brain, including metalloproteins, neurotrophic factors, amyloid proteins, and tau proteins. AD is caused by the aggregation of amyloid proteins in the brain. Factors such as metal ions, protein ligands, and the oligomerization state of amyloid precursor protein significantly influence the proteolytic processing of amyloid-β protein precursor (AβPP). Tau, a disordered cytosolic protein, serves as the principal microtubule-associated protein in mature neurons. AD patients exhibit decreased levels of nerve growth factor within their nervous systems and cerebrospinal fluid. Furthermore, a significant increase in brain-derived neurotrophic factor resulting from the neuroprotective effect of glial cell line-derived neurotrophic factor suggests that the synergistic action of these proteins plays a role in inhibiting neuronal degeneration and atrophy. The mechanism through which Aβ and AβPP govern Cu2+ transport and their influence on Cu2+ and other metal ion pools requires elucidation in future studies. A comprehensive understanding of the influence of aging and AD on molecular pathways and varying protein levels may hold the potential for the development of novel diagnostic and therapeutic methods for the treatment of AD.