Acupuncture Interventions for Alzheimer’s Disease and Vascular Cognitive Disorders: A Review of Mechanisms

Progress of Chinese Medicine in Regulating Microglial Polarization against Alzheimer's Disease

Alzheimer's disease (AD), the predominant form of dementia, is a neurodegenerative disorder of the central nervous system (CNS) characterized by a subtle onset and a spectrum of cognitive and functional declines. The clinical manifestation of AD encompasses memory deficits, cognitive deterioration, and behavioral disturbances, culminating in a severe impairment of daily living skills. Despite its high prevalence, accounting for 60-70% of all dementia cases, there remains an absence of curative therapeutics. Microglia (MG), the resident immune cells of the CNS, exhibit a bifurcated role in AD pathogenesis. Functioning in a neuroprotective capacity, MGs express scavenger receptors, facilitating the clearance of [Formula: see text]-amyloid protein (A[Formula: see text]) and cellular debris. Conversely, aberrant activation of MGs can lead to the secretion of pro-inflammatory cytokines, thereby propagating neuroinflammatory responses that are detrimental to neuronal integrity. The dynamics of MG activation and the ensuing neuroinflammation are pivotal in the evolution of AD. Chinese medicine (CM), a treasure trove of traditional Chinese cultural practices, has demonstrated significant potential in the therapeutic management of AD. Over the past triennium, CM has garnered considerable research attention for its multifaceted approaches to AD, including the regulation of MG polarization. This review synthesizes current knowledge on the origins, polarization dynamics, and mechanistic interplay of MG with AD pathology. It further explores the nexus between MG polarization and cardinal pathological hallmarks of AD, such as A[Formula: see text] plaque deposition, hyperphosphorylation of tau, synaptic plasticity impairments, neuroinflammation, and brain-gut-axis dysregulation. The review also encapsulates the therapeutic strategies of CM, which encompass monomers, formulae, and acupuncture. These strategies modulate MG polarization in the context of AD treatment, thereby providing a robust theoretical framework in which to conduct future investigative endeavors in both the clinical and preclinical realms.

Exploring the effects of moxibustion on cognitive function in rats with multiple cerebral infarctions from the perspective of glial vascular unit repairing

Objective

This study aimed to explore the effect of moxibustion at Governor Vessel (GV) acupoints, including Baihui (GV 20), Shenting (GV 24) and Dazhui (GV 14) for 14 days on glial vascular unit (GVU) in rats with multiple microinfarctions (MMI), and to explore its action mechanism.

Methods

The effect and mechanism of moxibustion on vascular dementia (VD) were studied in MMI rats by means of behavioral and molecular biology experiments.

Results

Rats receiving MMI showed impairment of memory function, reduction of cerebral blood flow, damage of blood-brain barrier (BBB) integrity and increased brain mass. MMI also increased neuronal degeneration in the hippocampus. Notably, levels of glial fibrillary acidic protein (GFAP) and complement component 3 significantly increased, but those of Connexin43 (CX43) and platelet derived growth factor receptor β (PDGFRβ) significantly decreased in the hippocampus of the rats receiving MMI. Moxibustion, as well as oxiracetam (ORC) treatment improved memory function and neuronal degeneration, ameliorated BBB integrity, increased cerebral blood flow and decreased brain mass. In addition, moxibustion as well as oxiracetam (ORC) treatment reduced the decrease of CX43 protein and increased PDGFRβ protein level in the hippocampus of MMI rats. Moreover, moxibustion treatment reversed MMI-induced increase of the GFAP/CX43 ratio in vascular structural units. Importantly, after PDGFRβ inhibition, VD rats treated with moxibustion had impaired learning and memory, decreased cerebral blood flow, and BBB disruption.

Conclusion

Moxibustion treatment at various GV acupoints improved cerebral blood flow and repaired BBB function in rats with MMI, likely through protecting GVU.

Acupuncture improves spatial learning and memory impairment caused by herpes simplex virus type-1 in rats through the p38 MAPK/CREB pathway

BACKGROUND

Acupuncture can improve herpes simplex encephalitis (HSE), but the underlying mechanism is not clear. Therefore, we evaluated the cognitive function and apoptosis in hippocampus caused by herpes simplex virus type-1 (HSV-1) in rats after acupuncture and described the molecular mechanism.

METHODS

Sprague-Dawley rats were induced into HSE models by HSV-1 infection. After 3 days, they received acupuncture at the acupoints of Xuanzhong (GB39), Baihui (GV20), Shenmen (HT7), Shenting (GV24), and Sanyinjiao (SP6), and/or intraperitoneal injection of the p38 MAPK inhibitor SB203580. Morris water maze test was performed on rats. The hippocampus of rats was obtained, and the expression of apoptosis-related genes in the tissues was detected by qRT-PCR. In addition, apoptosis-related proteins and proteins related to the p38 MAPK/CREB pathway in the tissues was detected by western blot.

RESULTS

After HSV-1 induction, the rat's escape latency was increased, the time spent on the platform in the target quadrant and the number of platform crossings significantly decreased. In addition, there was an increase in apoptosis in the hippocampus, accompanied by elevated levels of p-p38 and decreased levels of p-CREB. However, these effects could be improved by acupuncture treatment. Interestingly, SB203580 plays a similar role to acupuncture, and acupuncture could further enhance the impacts of SB203580 on cognitive function and apoptosis in hippocampus in HSE rats.

CONCLUSION

Acupuncture improves spatial learning and memory impairment caused by HSV-1 in rats. The functional mechanism of acupuncture may be through the p38 MAPK/CREB pathway.

Acupuncture and Acupoints for Managing Pediatric Cerebral Palsy: A Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Acupuncture is frequently used to manage pediatric cerebral palsy (CP), yet updated evidence is needed to guide future research and clinical practice.

METHODS

Seven databases were searched from 1994 to 26 June 2023. Randomized controlled trials (RCTs) involving body, scalp, or ear acupuncture for managing CP, excluding acupoint injection, catgut embedding, electro-acupuncture, or laser acupuncture, were included.

RESULTS

Twenty RCTs with 1797 participants were analyzed. Acupuncture groups had better improvements in gross motor function measure (GMFM) scores by 5% (mean difference: 5.93, 95% CI: 3.67-8.19, p < 0.001, I2 = 57%); a 16% higher probability to yield prominent improvement in effectiveness rate (ER) (risk ratio: 1.16, 95% CI: 1.08-1.25, p < 0.001, I2 = 0%); and better outcomes in the Modified Ashworth Scale (MAS) (standardized mean difference [SMD]: 0.3, 95%, CI: 0.11-0.49, p < 0.001, I2 = 0%), the Berg Balance Scale (BBS) (SMD: 2.48; 95% CI: 2.00-2.97, p < 0.001, I2 = 72%) and ADL (SMD: 1.66; 95% CI: 1.23-2.08, p < 0.001, I2 = 91%). Studies with eight core acupoints identified from all ninety-five acupoints had better ER.

CONCLUSIONS

Acupuncture, especially using core acupoints, may be effective for managing symptoms in children with CP.

Clinical effect of acupuncture at ghost points combined with fluoxetine hydrochloride on mild-to-moderate depression

BACKGROUND

Depression is a common, chronic, and recurrent mood disorder that has become a worldwide health hazard. Fluoxetine hydrochloride, a common treatment method, can inhibit 5-hydroxytryptamine (5-HT) recycling in the presynaptic membrane; however, the efficacy of a single drug is inadequate. At present, mild-to-moderate depression can be treated with acupuncture of ghost caves, but the clinical curative effect of combined therapy with fluoxetine hydrochloride has not been sufficiently reported.

AIM

To evaluate the clinical effect of acupuncture at ghost points combined with fluoxetine hydrochloride in the treatment of mild-to-moderate depression.

METHODS

This retrospective study included 160 patients with mild-to-moderate depression who were admitted to Shanghai Hospital of Integrated Traditional Chinese and Western Medicine, Affiliated to Shanghai University of Traditional Chinese Medicine, between January 2022 and June 2023. Patients were separated into a single-agent group (fluoxetine hydrochloride treatment, n = 80) and a coalition group (fluoxetine hydrochloride treatment combined with acupuncture at ghost points, n = 80). Pre-treatment symptoms were recorded, and the clinical curative effect and adverse reactions [Asberg Antidepressant Side Effects Scale (SERS)] were assessed. Depression before and after treatment [Hamilton Depression Scale (HAMD)-24], neurotransmitter levels [5-HT, norepinephrine (NE), dopamine (DA)], oxidative stress indicators [superoxide dismutase (SOD), malondialdehyde (MDA)], and sleep quality [Pittsburgh Sleep Quality Index (PSQI)] were compared.

RESULTS

The total efficacy rate was 97.50% in the coalition group and 86.25% in the single-agent group (P < 0.05). After 2, 4, 6, and 8 wk of treatment, the HAMD, self-rating depression scale, and SERS scores of the coalition and single-agent groups decreased compared with pre-treatment, and the decrease was more significant in the coalition group (P < 0.05). After 8 wk of treatment, the levels of NE, DA, 5-HT, and SOD in the coalition and single-agent groups increased, while the levels of MDA decreased; the increases and decrease in the coalition group were more significant (P < 0.05). The PSQI scores of the coalition and single-agent groups decreased, and the decrease was more significant in the coalition group (P < 0.05).

CONCLUSION

Acupuncture at ghost points combined with paroxetine tablets can safely improve depressive symptoms and sleep disorders, regulate neurotransmitter levels, and reduce stress responses in patients with mild-to-moderate depression.

Hippocampal synaptic plasticity injury mediated by SIRT1 downregulation is involved in chronic pain-related cognitive dysfunction

AIMS

Cognitive dysfunction associated with chronic pain may be caused by impaired synaptic plasticity. Considering the impact of silent information regulator 1 (SIRT1) on synaptic plasticity, we explored the exact role of SIRT1 in cognitive impairment caused by chronic pain.

METHODS

We evaluated the memory ability of mice with the fear conditioning test (FCT) after spared nerve injury (SNI) model. Western blotting and immunofluorescence were used to analyze the expression levels of SIRT1. Hippocampal synaptic plasticity was detected with Golgi staining, transmission electron microscopy, and long-term potentiation (LTP). In the intervention study, AAV9-CaMKIIα-Cre-EGFP was injected to SIRT1flox/flox mice to knockdown the expression levels of SIRT1. Besides, SNI mice were injected with AAV2/9-CaMKIIα-SIRT1-3*Flag-GFP or SRT1720 to increase the expression levels or enzymatic activity of SIRT1.

RESULTS

Our current results indicated that cognitive function in SNI mice was impaired, SIRT1 expression in glutaminergic neurons in the hippocampal CA1 area was downregulated, and synaptic plasticity was altered. Selective knockdown of SIRT1 in hippocampus damaged synaptic plasticity and cognitive function of healthy mice. In addition, the impaired synaptic plasticity and cognitive dysfunction of SNI mice could be improved by the upregulation of SIRT1 expression or enzyme activity.

CONCLUSIONS

Reduced SIRT1 expression in hippocampus of SNI mice may induce cognitive impairment associated with chronic pain by mediating the impaired synaptic plasticity.

Acupuncture and moxibustion therapy for cognitive impairment: the microbiome-gut-brain axis and its role

Cognitive impairment poses a significant burden on individuals, families, and society worldwide. Despite the lack of effective treatment strategies, emerging evidence suggests that the microbiome-gut-brain (MGB) axis may play a critical role in the pathogenesis of cognitive impairment. While targeted treatment is not yet comprehensive, recently, acupuncture and moxibustion therapy has participated increasingly in the treatment of degenerative diseases and has achieved a certain therapeutic effect. In this review, the possible mechanisms by which acupuncture and moxibustion therapy may improve cognitive impairment through the MGB axis are reviewed, including regulating gut microbial homeostasis, improving intestinal inflammation mediated by the neuroendocrine-immune system, and enhancing intestinal barrier function. We also discuss common acupoints and corresponding mechanism analysis to provide insights into further exploration of mechanisms that target the MGB axis and thereby intervene in cognitive impairment.

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.

Electroacupuncture treatment ameliorates metabolic disorders in obese ZDF rats by regulating liver energy metabolism and gut microbiota

Metabolic disorders represent a major therapeutic challenge to public health worldwide due to their dramatically increasing prevalence. Acupuncture is widely used as adjuvant therapy for multiple metabolic diseases. However, detailed biological interpretation of the acupuncture stimulations is still limited. The gut and the liver are intrinsically connected and related to metabolic function. Microbial metabolites might affect the gut-liver axis through multiple mechanisms. Liver metabolomics and 16S rRNA sequencing were used to explore the specific mechanism of electroacupuncture in treating ZDF rats in this study. Electroacupuncture effectively improved glycolipid metabolism disorders of the ZDF rats. Histopathology confirmed that electroacupuncture improved diffuse hepatic steatosis and hepatocyte vacuolation, and promoted glycogen accumulation in the liver. The treatment significantly improved microbial diversity and richness and upregulated beneficial bacteria that maintain intestinal epithelial homeostasis and decreased bacteria with detrimental metabolic features on host metabolism. Liver metabolomics showed that the main effects of electroacupuncture include reducing the carbon flow and intermediate products in the TCA cycle, regulating the metabolism of various amino acids, and inhibiting hepatic glucose output and de novo lipogenesis. The gut-liver axis correlation analysis showed a strong correlation between the liver metabolites and the gut microbiota, especially allantoin and Adlercreutzia. Electroacupuncture treatment can improve abnormal energy metabolism by reducing oxidative stress, ectopic fat deposition, and altering metabolic fluxes. Our results will help us to further understand the specific mechanism of electroacupuncture in the treatment of metabolic diseases.