Yuanzhi Powder inhibits tau pathology in SAMP8 mice: Mechanism research of a traditional Chinese formula against Alzheimer's disease

Multi-strain probiotics ameliorate Alzheimer's-like cognitive impairment and pathological changes through the AKT/GSK-3β pathway in senescence-accelerated mouse prone 8 mice

BACKGROUND

Alzheimer's disease (AD), the most prevalent type of dementia, still lacks disease-modifying treatment strategies. Recent evidence indicates that maintaining gut microbiota homeostasis plays a crucial role in AD. Targeted regulation of gut microbiota, including probiotics, is anticipated to emerge as a potential approach for AD treatment. However, the efficacy and mechanism of multi-strain probiotics treatment in AD remain unclear.

METHODS

In this study, 6-month-old senescence-accelerated-mouse-prone 8 (SAMP8) and senescence-accelerated-mouse-resistant 1 (SAMR1) were utilized. The SAMP8 mice were treated with probiotic-2 (P2, a probiotic mixture of Bifidobacterium lactis and Lactobacillus rhamnosus) and probiotic-3 (P3, a probiotic mixture of Bifidobacterium lactis, Lactobacillus acidophilus, and Lactobacillus rhamnosus) (1 × 109 colony-forming units) once daily for 8 weeks. Morris water maze (MWM) and novel object recognition (NOR) tests were employed to assess the memory ability. 16S sequencing was applied to determine the composition of gut microbiota, along with detecting serum short-chain fatty acids (SCFAs) concentrations. Neural injury, Aβ and Tau pathology, and neuroinflammation level were assessed through western blot and immunofluorescence. Finally, potential molecular mechanisms was explored through transcriptomic analysis and western blotting.

RESULTS

The MWM and NOR test results indicated a significant improvement in the cognitive level of SAMP8 mice treated with P2 and P3 probiotics compared to the SAMP8 control group. Fecal 16S sequencing revealed an evident difference in the α diversity index between SAMP8 and SAMR1 mice, while the α diversity of SAMP8 mice remained unchanged after P2 and P3 treatment. At the genus level, the relative abundance of ten bacteria differed significantly among the four groups. Multi-strain probiotics treatment could modulate serum SCFAs (valeric acid, isovaleric acid, and hexanoic acid) concentration. Neuropathological results demonstrated a substantial decrease in neural injury, Aβ and Tau pathology and neuroinflammation in the brain of SAMP8 mice treated with P3 and P2. Transcriptomic analysis identified the chemokine signaling pathway as the most significantly enriched signaling pathway between SAMP8 and SAMR1 mice. Western blot test indicated a significant change in the phosphorylation level of downstream AKT/GSK-3β between the SAMP8 and SAMR1 groups, which could be reversed through P2 and P3 treatment.

CONCLUSIONS

Multi-strain probiotics treatment can ameliorate cognitive impairment and pathological change in SAMP8 mice, including neural damage, Aβ and Tau pathology, and neuroinflammation. This effect is associated with the regulation of the phosphorylation of the AKT/GSK-3β pathway.

Advances in Alzheimer's disease: A multifaceted review of potential therapies and diagnostic techniques for early detection

Alzheimer's disease (AD) remains one of the most formidable neurological disorders, affecting millions globally. This review provides a holistic overview of the therapeutic strategies, both conventional and novel, aimed at mitigating the impact of AD. Initially, we delve into the conventional approach, emphasizing the role of Acetylcholinesterase (AChE) inhibition, which has been a cornerstone in AD management. As our understanding of AD evolves, several novel potential approaches emerge. We discuss the promising roles of Butyrylcholinesterase (BChE) inhibition, Tau Protein inhibitors, COX-2 inhibition, PPAR-γ agonism, and FAHH inhibition, among others. The potential of the endocannabinoids (eCB) system, cholesterol-lowering drugs, metal chelators, and MMPs inhibitors are also explored, culminating in the exploration of the pivotal role of microRNA in AD progression. Parallel to these therapeutic insights, we shed light on the novel tools and methodologies revolutionizing AD research. From the quantitative analysis of gene expression by qRTPCR to the evaluation of mitochondrial function using induced pluripotent stem cells (iPSCs), the advances in diagnostic and research tools offer renewed hope. Moreover, we explore the current landscape of clinical trials, highlighting the leading drug interventions and their respective stages of development. This comprehensive review concludes with a look into the future perspectives, capturing the potential breakthroughs and innovations on the horizon. Through a synthesis of current knowledge and emerging research, this article aims to provide a consolidated resource for clinicians, researchers, and academicians in the realm of Alzheimer's disease.

Yuanzhi powder facilitated Aβ clearance in APP/PS1 mice: Target to the drainage of glymphatic system and meningeal lymphatic vessels

ETHNOPHARMACOLOGICAL RELEVANCE

Yuanzhi Powder (YZP) is a classical Chinese medicine prescription, which is suitable for the treatment of dementia by "dispelling phlegm and opening orifice". The therapeutic efficacy of YZP on Alzheimer's disease (AD) has been previously reported in our work. However, it remains unclear whether the neuroprotective effect of YZP is linked to β-amyloid(Aβ) clearance through cerebral lymphatic drainage.

AIM OF THE STUDY

The aim was to determine the protective efficacy of YZP against AD and investigate the potential mechanism for eliminating excessive Aβ deposition.

MATERIALS AND METHODS

APP/PS1 mice were divided into four groups of 8 mice each: APP/PS1 group, DONE group, L-YZP group, and H-YZP group. Additionally, 8 wild-type littermates were assigned to the control group (WT group). After 8 weeks of consecutive intragastric administration, behavioral tests, including the open field test, novel object recognition test and Morris Water Maze test, were employed to assess the cognitive abilities of all groups of mice. Nissl staining, immunohistochemistry, and western blotting were utilized to evaluate clearance of excessive Aβ deposition and pathological changes. Furthermore, immunofluorescence was applied to visualize the drainage of the cerebral lymphatic system after fluorescent tracer injection in the cisterna magna.

RESULTS

The administration of YZP significantly attenuated cognitive deficits, cleared excessive Aβ deposition, and improved pathological damage in APP/PS1 mice. Furthermore, YZP effectively enhanced glymphatic system drainage by restoring AQP4 polarization and inhibiting reactive astrogliosis. Additionally, YZP facilitated the drainage of meningeal lymphatic vessels (MLVs) by augmenting their diameter and coverage. Lastly, YZP promoted the elimination of Aβ from the brain to deep cervical lymph nodes.

CONCLUSIONS

The administration of YZP may ameliorate the cognitive deficits and pathological damage in APP/PS1 mice by effectively clearing excessive Aβ deposition. The underlying mechanisms potentially involve Aβ clearance through the cerebral lymphatic system, which includes the glymphatic system and MLVs.

Polygala tenuifolia and Acorus tatarinowii in the treatment of Alzheimer's disease: a systematic review and meta-analysis

Background: The complexity of Chinese medicine treatment for Alzheimer's disease (AD) utilizing a multi-herb therapy makes the evidence in current studies insufficient. Herb pairs are the most fundamental form of multi-herb formulae. Among the Chinese herbal formulas for AD treatment, Polygala tenuifolia (PT) and Acorus tatarinowii (AT) appeared as the most commonly used herbal pairs in combination. Objective: The aim of this study is to evaluate the clinical efficacy and safety of the combination of PT and AT in the treatment of AD. Methods: We systematically searched and screened randomized controlled trials of pairing PT and AT for the treatment of AD patients in eight databases with a search deadline of June 26, 2023. Authors, year of publication, title, and basic information such as subject characteristics (age, sex, and race), course of disease, control interventions, dose, and treatment duration were extracted from the screened studies. Primary outcomes assessed included mini-mental state examination (MMSE), activities of daily living (ADL), and AD assessment scale-cognitive subscale (ADAS-cog), while secondary outcomes included efficiency and adverse events. The quality of the included studies was assessed using the Cochrane risk of bias tool. The mean difference with 95% confidence intervals (MD [95% CI]) and risk ratio (RR) was selected as the effect size, and the data were analyzed and evaluated using RevMan 5.4 and Stata 16. Results: A total of sixteen eligible and relevant studies involving 1103 AD participants were included. The combination of PT and AT plus conventional drugs was superior to single conventional drugs in MMSE [MD = 2.57, 95%CI: (1.44, 3.69); p < 0.00001; I 2 = 86%], ADL [MD = -3.19, 95%CI: (-4.29, -2.09); p < 0.00001; I 2 = 0%], and ADAS-cog scores [MD = -2.09, 95%CI: (-3.07, -1.10); p < 0.0001; I 2 = 0%]. The combination of PT and AT plus conventional drugs had a significantly more favorable benefit in clinical effectiveness [RR = 1.27, 95%CI: (1.12, 1.44); p = 0.0002; I 2 = 0%]. Adverse events were not increased with the combination of PT and AT plus conventional drugs compared to conventional drugs [RR = 0.65, 95%CI: (0.35, 1.19); p = 0.16; I 2 = 0%]. The experimental group treated with the combination of PT and AT alone for AD was comparable in MMSE, ADL, and ADAS-cog scores compared with the control group treated with single conventional drugs. Conclusion: Compared to single conventional drugs, the combination of PT and AT may be used as an alternative therapy to improve global cognition and functioning in AD, and the combination of PT and AT as adjunctive therapy appears to produce a better therapeutic response to AD in terms of efficacy without increasing the risk of adverse events. However, the very low to low quality of available evidence limits confidence in the findings. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42023444156.

Geniposide attenuates muscle atrophy via the inhibition of FoxO1 in senescence-accelerated mouse prone-8

BACKGROUND

Geniposide (GP) is an iridoid glycoside that is present in nearly 40 species, including Gardenia jasminoides Ellis. GP has been reported to exhibit neuroprotective effects in various Alzheimer's disease (AD) models; however, the effects of GP on AD models of Caenorhabditis elegans (C. elegans) and aging-accelerated mouse predisposition-8 (SAMP8) mice have not yet been evaluated.

PURPOSE

To determine whether GP improves the pathology of AD and sarcopenia.

METHODS

AD models of C. elegans and SAMP8 mice were employed and subjected to behavioral analyses. Further, RT-PCR, histological analysis, and western blot analyses were performed to assess the expression of genes and proteins related to AD and muscle atrophy.

RESULTS

GP treatment in the AD model of C. elegans significantly restored the observed deterioration in lifespan and motility. In SAMP8 mice, GP did not improve cognitive function deterioration by accelerated aging but ameliorated physical function deterioration. Furthermore, in differentiated C2C12 cells, GP ameliorated muscle atrophy induced by dexamethasone treatment and inhibited FoxO1 activity by activating AKT.

CONCLUSION

Although GP did not improve the AD pathology in SAMP8 mice, we suggest that GP has the potential to improve muscle deterioration caused by aging. This effect of GP may be attributed to the suppression of FoxO1 activity.