Acupuncture Improves White Matter Perfusion and Integrity in Rat Model of Vascular Dementia: An MRI-Based Imaging Study

The Impact of Dipyridamole on Disease-Associated Microglia Phenotypic Transformation in White Matter Lesions Induced by Chronic Cerebral Hypoperfusion

White matter lesions (WMLs) resulting from chronic cerebral hypoperfusion (CCH) are the leading cause of vascular dementia (VaD). This study aimed to investigate whether dipyridamole could alleviate WMLs by regulating the phenotype of disease-associated microglia (DAM) through equilibrative nucleoside transporter 2 (ENT2) and adenosine A2A receptor (Adora2a) and to clarify the underlying molecular mechanisms. CCH rat models were constructed to mimic VaD. Morris water maze and Luxol Fast Blue staining were employed to assess cognitive function and quantify the severity of WMLs, respectively. Immunofluorescent staining was performed to analyze the activation of glial cells and the phenotypic transformation of DAM. Additionally, levels of ENT2, proteins in the NF-κB and ERK1/2 pathways and inflammatory cytokines were detected. The results indicated that dipyridamole diminished the activation and proliferation of microglia and astrocytes, increased the expression of myelin basic protein and ameliorated WMLs and cognitive decline in CCH rats. Further study revealed that dipyridamole decreased the expression of ENT2 and inhibited the activation of ERK1/2 and NF-κB signaling pathways, which ultimately converted DAM to anti-inflammatory phenotype and suppressed the levels of TNF-α, IL-1β, IL-6 in WMLs. However, Adora2a inhibitor (SCH58261) attenuated above effects. Our study demonstrates that dipyridamole facilitates the conversion of DAM to the anti-inflammatory phenotype through ENT2/Adora2a pathway and inhibits the activation of ERK1/2 and NF-κB signaling pathways, thereby alleviating neuroinflammation in WMLs. The current findings establish the basis for using dipyridamole to treat VaD.

Neurovascular glial unit: A target of phytotherapy for cognitive impairments

BACKGROUND

Neurovascular glial unit (NVGU) dysfunction has been reported to be an early and critical event in the pathophysiology of Alzheimer's disease (AD) and vascular dementia (VD). Although herbal medicines, with their favorable safety profiles and low adverse effects, have been suggested to be useful for the treatment of cognitive impairment, the potential role of the NVGU as the target of the effects of herbal medicines is still unclear.

PURPOSE

This review aimed to retrieve evidence from experimental studies of phytopharmaceuticals targeting the NVGU for the treatment of cognitive impairment in AD and VD, and discussed the potential of phytopharmaceuticals to improve cognitive impairment from the perspective of the NVGU.

STUDY DESIGN AND METHODS

We systematically searched PubMed, Google Scholar, Web of Science, and CNKI. The keywords used for searching information on the NVGU in the treatment of cognitive impairments included "Alzheimer's disease," "Vascular dementia," "Herbal medicines," "Natural products," "Neurovascular," "Adverse reaction," and "Toxicity, etc." We selected studies on the basis of predefined eligibility criteria.

RESULTS

NVGU mainly consists of endothelial cells, pericytes, astrocytes, microglia, oligodendrocytes, and neurons, and damage to these cells can induce cognitive impairment by impairing the blood-brain barrier (BBB) and cerebral blood flow (CBF) as well as neuronal function. The active components of herbal medicines, including Ginkgo biloba L., Ginseng Radix et Rhizoma, Epimedium Folium, Chuanxiong Rhizoma, Carthami flos, and Acorus tatarinowii Schott, as well as traditional Chinese medicine prescriptions have shown the potential to improve BBB function and increase CBF to prevent cognitive impairment by inhibiting astrocyte and microglia activation, protecting oligodendrocyte myelin function, reducing neuronal apoptosis, and promoting angiogenesis.

CONCLUSIONS

Herbal medicines demonstrate great potential to prevent cognitive impairment. Multiple components from herbal medicines may function through different signaling pathways to target the NVGU. Future studies using novel drug-carrier or delivery systems targeting the NVGU will certainly facilitate the development of phytopharmaceuticals for AD and VD.

The effects and mechanisms of acupuncture for post-stroke cognitive impairment: progress and prospects

Stroke is one of the important causes of both disability and death worldwide, which is very common in older adults. Post-stroke cognitive impairment (PSCI) is a common secondary damage of stroke, which is the main cause of long-term disability and decreased quality of life in stroke patients, which brings a heavy burden to society and families. Acupuncture, as one of the oldest and widely used worldwide techniques in Chinese medicine, is recommended by the World Health Organization (WHO) as an alternative and complementary strategy for improving stroke care. This review comprehensively summarizes literature from the last 25 years, showing that acupuncture can exert strong beneficial effect on PSCI. The mechanisms of acupuncture on PSCI involves anti-neuronal apoptosis, promoting synaptic plasticity, alleviating central and peripheral inflammatory reactions, and regulating brain energy metabolism disorders (including improving cerebral blood flow, glucose utilization and mitochondrial structure and function, etc.), etc. The effects and mechanisms of acupuncture on PSCI reviewed in this study provides scientific and reliable evidence for acupuncture application for PSCI.

Can acupuncture reverse oxidative stress and neuroinflammatory damage in animal models of vascular dementia?: A preclinical systematic review and meta-analysis

BACKGROUND

Vascular dementia is a cognitive dysfunction syndrome caused by cerebral vascular factors such as ischemic stroke and hemorrhagic stroke. The effect of acupuncture on vascular dementia models is ambiguous, and there is controversy about whether acupuncture has a placebo effect. Oxidative stress and inflammation are the most essential mechanisms in preclinical studies of vascular dementia. However, there is no meta-analysis on the mechanism of vascular dementia in animal models. It is necessary to explore the efficacy of acupuncture through Meta-analysis of preclinical studies.

METHODS

Three major databases, PubMed, Embase and Web of Science (including medline), were searched in English until December 2022.The quality of the including literature was assessed using SYRCLE's risk of bias tool. Review Manager 5.3 was used to statistically summarize the included studies and the statistical effect values were expressed by SMD. The outcomes included: behavioral tests (escape latency, number of crossings), pathological sections (Nissl and TUNEL staining), oxidative stress markers (ROS, MDA, SOD, GSH-PX) and neuroinflammatory factors (TNF-α, IL-1β, IL-6).

RESULTS

A total of 31 articles were included in this meta-analysis. The results showed that the escape latency, the contents of ROS, MDA, IL-1β, and IL-6 were decreased, and the contents of SOD and Nissl-positive neurons were increased in the acupuncture group as compared with the non-group (P < .05). Compared with the impaired group, the acupuncture group also had the above advantages (P < .05). In addition, the acupuncture group also increased the number of crossings and GSH-PX content, and decreased the expression of TUNEL-positive neurons and TNF-α (P < .05).

CONCLUSIONS

From behavioral tests to slices and pathological markers in animal models of vascular dementia, it can be proved that acupuncture is effective in targeting oxidative stress and neuroinflammatory damage, and acupuncture is not a placebo effect. Nevertheless, attention needs to be paid to the gap between animal experiments and clinical applications.

Electroacupuncture promotes remyelination and alleviates cognitive deficit via promoting OPC differentiation in a rat model of subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a devastating cerebral vascular disease which causes neurological deficits including long-term cognitive deficit. Demyelination of white matter is correlated with cognitive deficit in SAH. Electroacupuncture (EA) is a traditional Chinese medical treatment which protects against cognitive deficit in varies of neurological diseases. However, whether EA exerts protective effect on cognitive function in SAH has not been investigated. The underlying mechanism of remyelination regulated by EA remains unclear. This study aimed to investigate the protective effects of EA on cognitive deficit in a rat model of SAH. SAH was induced in SD rats (n = 72) by endovascular perforation. Rats in EA group received EA treatment (10 min per day) under isoflurane anesthesia after SAH. Rats in SAH and sham groups received the same isoflurane anesthesia with no treatment. The mortality rate, neurological score, cognitive function, cerebral blood flow (CBF), and remyelination in sham, SAH and EA groups were assessed at 21 d after SAH.EA treatment alleviated cognitive deficits and myelin injury of rats compared with that in SAH group. Moreover, EA treatment enhanced remyelination in white matter and promoted the differentiation of OPCs after SAH. EA treatment inhibited the expression of Id2 and promoted the expression of SOX10 in oligodendrocyte cells. Additionally, the cerebral blood flow (CBF) of rats was increased by EA compared with that in SAH group. EA treatment exerts protective effect against cognitive deficit in the late phase of SAH. The underlying mechanisms involve promoting oligodendrocyte progenitor cell (OPC) differentiation and remyelination in white matter via regulating the expression of Id2 and SOX10. The improvement of CBF may also account for the protective effect of EA on cognitive function. EA treatment is a potential therapy for the treatment of cognitive deficit after SAH.

Electroacupuncture and manual acupuncture at LR3 and ST36 have attenuating effects on hypertension and subsequent cognitive dysfunction in spontaneously hypertensive rats: A preliminary resting-state functional magnetic resonance imaging study

Introduction

Chronic hypertension may have a contributory role toward cognitive impairment. Acupuncture exerts protective effects on cognitive functions while controlling the blood pressure. However, the neural mechanism underlying the dual attenuating effect of acupuncture remains unclear. In this study, we investigated the effects of electroacupuncture (EA) and manual acupuncture (MA) on the functional activity of the brain regions of spontaneously hypertensive rats (SHRs) by through resting-state functional magnetic resonance imaging (rs-fMRI). We also evaluated the differences in these functional activities between the EA and MA groups.

Methods

We randomly assigned 30 SHRs into the EA, MA, and model (SHR) groups. Wistar Kyoto rats (n = 10) were used as normal control (WKY). The interventions were administered once every alternate day for 12 weeks. The systolic blood pressure of all rats was recorded every 2 weeks until the end of the intervention. After the intervention, rs-fMRI scanning was performed to access the whole brain data of rats randomly selected from each group evenly. The amplitude of low frequency fluctuation (ALFF) analysis, regional homogeneity (ReHo) analysis, and functional connectivity (FC) analysis were also conducted. The Morris water maze (MWM) test was conducted to evaluate the learning and memory of the rats. Hematoxylin-eosin staining and Nissl staining were performed to observe histopathological changes in the key brain regions.

Results

We demonstrated that, when compared with the SHR group, the EA and MA groups had significantly lower blood pressure and better performance for behavioral test indices, and that the effect of EA was better than that of MA. ALFF and ReHo analyses revealed enhancement of the neuronal activity of some functionally impaired brain areas in the EA and MA groups. The main callback brain regions included the hypothalamus, entorhinal cortex, brain stem, prelimbic cortex, cingulate cortex, corpus callosum, and cerebellum. The FC analysis demonstrated that EA and MA enhanced the functional connectivity between the seeds and brain regions such as the brain stem, entorhinal cortex, hippocampus, prelimbic cortex, and cerebellum. The pathological test of the entorhinal cortex also verified the protective effect of acupuncture on the neuronal functional activity.

Discussion

Our findings suggested that EA and MA exhibited attenuating effects on hypertension and cognitive dysfunction by enhancing the functional activities in the corresponding brain regions. Moreover, EA activated more callback brain regions and functional connectivity than MA, which may explain why the effect of EA was better than that of MA.

Efficacy of acupuncture in animal models of vascular dementia: A systematic review and network meta-analysis

Background and purpose

Acupuncture is widely used in clinical practice for the treatment of vascular diseases. However, the protocol, efficacy, and mechanism of acupuncture in animal models of vascular dementia are still controversial. Based on the above problems, we initiated this comprehensive study.

Methods

To analyze the literatures included in this study, 4 databases were searched and the SYRCLE's Risk of bias tool was employed. To perform the subgroup analysis of different acupuncture methods and the Review Manager 5.3 was applied. Meanwhile, the pairwise and network meta-analysis were conducted using Addis 1.16.8. The outcomes included escape latency, number of crossings, time spent in the target quadrant, and swimming speed.

Results

Forty-two studies with a total of 1,486 animals were included in this meta-analysis. According to the results from subgroup analysis, GV20 + ST36 (Baihui + bilateral Zusanli) combined with 14-day manual acupuncture can obtain best improvement of the rats cognitive function among all acupuncture regimens (MD: -23.41; 95%CI: -26.66, -20.15; I2 = 0%; P < 0.001). The heterogeneity of other acupuncture treatments was significantly higher than that of GV20 + ST36, because the treatment courses were not uniform. Pair-wise and network comparisons are highly consistent. The major results of the network meta-analysis were as follows, In comparison to the impaired group, the acupuncture group showed significantly reduced escape latency (MD: -25.87; 95%CI: -30.75, -21.12), increased number of original platform crossings (MD: 2.63; 95%CI: 1.94, 3.34) and time spent in the target quadrant (MD: 7.88; 95%CI: 4.25, 11.44). The overall results of the network meta-analysis are as follows: the normal and sham-operated groups performed the best, followed by medicine and acupuncture, while no effect was found in the impaired group treated with non-acupoint and palliative.

Conclusions

Acupuncture significantly improves cognitive function in rats with vascular dementia. Compared to other acupuncture plans, (GV20 + ST36, MA) and 14 -day manual acupuncture can be used to obtain better results. The main mechanism of acupuncture in the treatment of vascular dementia is reduced oxidative stress, neuronal inflammation, and apoptosis, as well as the increased synaptic plasticity and neurotransmitters.

Systematic review registration

https://inplasy.com/inplasy-2021-11-0036/, identifier: INPLASY2021110036.

Acupuncture Treatment is Associated with Reduced Dementia Risk in Patients with Migraine: A Propensity-Score-Matched Cohort Study of Real-World Data

BACKGROUND

Migraine is a recurrent headache disease that has been identified as a risk factor for subsequent dementia. The present study collected data from Taiwan's National Health Insurance Research Database (NHIRD) to investigate the incidence of dementia in patients with migraine who did or did not concurrently receive acupuncture treatment.

METHODS

A 1:1 propensity score method was used to match an equal number of patients (N = 4813) in the acupuncture and nonacupuncture cohorts based on sex, age, migraine diagnosis year, index year, insurance amount, urbanization level, baseline comorbidities, and medication usage. We employed Cox proportional hazards models to evaluate the risk of dementia.

RESULTS

Patients with migraine who received acupuncture treatment were found to have a lower risk of dementia (adjusted hazard ratio [aHR] = 0.51, 95% CI = 0.40-0.65) than those who did not undergo acupuncture treatment. The cumulative incidence of dementia was significantly lower in the acupuncture cohort than in the nonacupuncture cohort (Log rank test, p < 0.001). This propensity score-matched cohort study demonstrated an association between acupuncture treatment and dementia development in patients with migraine in Taiwan.

CONCLUSION

The results suggest that acupuncture treatment significantly reduced the development of dementia in patients with migraine.