Phytocannabinoids as Potential Multitargeting Neuroprotectants in Alzheimer’s Disease

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“The Endocannabinoid System (ECS) is a well-studied system that influences a variety of physiological activities. It is evident that the ECS plays a significant role in metabolic activities and also has some neuroprotective properties.

In this review, we emphasize several plant-derived cannabinoids such as β-caryophyllene (BCP), Cannabichromene (CBC), Cannabigerol (CBG), Cannabidiol (CBD), and Cannabinol (CBN), which are known to have distinctive modulation abilities of ECS. In Alzheimer’s disease (AD), the activation of ECS may provide neuroprotection by modulating certain neuronal circuitry pathways through complex molecular cascades.

The present article also discusses the implications of cannabinoid receptors (CB1 and CB2) as well as cannabinoid enzymes (FAAH and MAGL) modulators in AD. Specifically, CBR1 or CB2R modulations result in reduced inflammatory cytokines such as IL-2 and IL-6, as well as a reduction in microglial activation, which contribute to an inflammatory response in neurons. Furthermore, naturally occurring cannabinoid metabolic enzymes (FAAH and MAGL) inhibit the NLRP3 inflammasome complex, which may offer significant neuroprotection.

In this review, we explored the multi-targeted neuroprotective properties of phytocannabinoids and their possible modulations, which could offer significant benefits in limiting AD.”

https://pubmed.ncbi.nlm.nih.gov/37132109/

https://www.eurekaselect.com/article/131371

Δ8-THC Protects against Amyloid Beta Toxicity Modulating ER Stress In Vitro: A Transcriptomic Analysis

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“Alzheimer’s disease (AD) represents the most common form of dementia, characterized by amyloid β (Aβ) plaques and neurofibrillary tangles (NFTs). It is characterized by neuroinflammation, the accumulation of misfolded protein, ER stress and neuronal apoptosis. It is of main importance to find new therapeutic strategies because AD prevalence is increasing worldwide.

Cannabinoids are arising as promising neuroprotective phytocompounds. In this study, we evaluated the neuroprotective potential of Δ8-THC pretreatment in an in vitro model of AD through transcriptomic analysis.

We found that Δ8-THC pretreatment restored the loss of cell viability in retinoic acid-differentiated neuroblastoma SH-SY5Y cells treated with Aβ1-42. Moreover, the transcriptomic analysis provided evidence that the enriched biological processes of gene ontology were related to ER functions and proteostasis. In particular, Aβ1-42 upregulated genes involved in ER stress and unfolded protein response, leading to apoptosis as demonstrated by the increase in Bax and the decrease in Bcl-2 both at gene and protein expression levels. Moreover, genes involved in protein folding and degradation were also deregulated. On the contrary, Δ8-THC pretreatment reduced ER stress and, as a consequence, neuronal apoptosis.

Then, the results demonstrated that Δ8-THC might represent a new neuroprotective agent in AD.”

https://pubmed.ncbi.nlm.nih.gov/37047608/

“The results suggested that Δ8-THC may represent a novel neuroprotective agent in AD but also in other neurodegenerative diseases characterized by the accumulation of misfolded proteins.”

https://www.mdpi.com/1422-0067/24/7/6598

The Cannabinoids, CBDA and THCA, Rescue Memory Deficits and Reduce Amyloid-Beta and Tau Pathology in an Alzheimer’s Disease-like Mouse Model

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“Most studies related to hemp are focused on Cannabidiol (CBD) and Tetrahydrocannabinol (THC); however, up to 120 types of phytocannabinoids are present in hemp. Hemp leaves contain large amounts of Cannabidiolic acid (CBDA) and Tetrahydrocannabinolic acid (THCA), which are acidic variants of CBD and THC and account for the largest proportion of CBDA.

In recent studies, CBDA exhibited anti-hyperalgesia and anti-inflammatory effects. THCA also showed anti-inflammatory and neuroprotective effects that may be beneficial for treating neurodegenerative diseases. CBDA and THCA can penetrate the blood-brain barrier (BBB) and affect the central nervous system.

The purpose of this study was to determine whether CBDA and THCA ameliorate Alzheimer’s disease (AD)-like features in vitro and in vivo. The effect of CBDA and THCA was evaluated in the Aβ1-42-treated mouse model. We observed that Aβ1-42-treated mice had more hippocampal Aβ and p-tau levels, pathological markers of AD, and loss of cognitive function compared with PBS-treated mice. However, CBDA- and THCA-treated mice showed decreased hippocampal Aβ and p-tau and superior cognitive function compared with Aβ1-42-treated mice. In addition, CBDA and THCA lowered Aβ and p-tau levels, alleviated calcium dyshomeostasis, and exhibited neuroprotective effects in primary neurons.

Our results suggest that CBDA and THCA have anti-AD effects and mitigate memory loss and resilience to increased hippocampal Ca2+, Aβ, and p-tau levels. Together, CBDA and THCA may be useful therapeutic agents for treating AD.”

https://pubmed.ncbi.nlm.nih.gov/37047798/

https://www.mdpi.com/1422-0067/24/7/6827

Multi-Targeting Intranasal Nanoformulation as a Therapeutic for Alzheimer’s Disease

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“Melatonin, insulin, and Δ9-tetrahydrocannabinol (THC) have been shown to reverse cognitive deficits and attenuate neuropathologies in transgenic mouse models of Alzheimer’s disease (AD) when used individually. Here, we evaluated the therapeutic properties of long-term intranasal treatment with a novel nanoformulation containing melatonin, insulin, and THC in aged APPswe/PS1ΔE9 (APP/PS1) mice, a transgenic model of AD.

Transgenic mice at the age of 12 months were intranasally administered with a new nanoformulation containing melatonin, insulin, and THC at doses of 0.04, 0.008, and 0.02 mg/kg, respectively, once daily for 3 months. The spatial memory of the mice was assessed using the radial arm water maze (RAWM) test before and after drug treatment. Brain tissues were collected at the end of the treatment period for the assessment of Aβ load, tauopathy state, and markers of mitochondrial function.

The RAWM test revealed that the treatment with the melatonin-insulin-THC (MIT) nasal spray improved the spatial learning memory of APP/PS1 mice significantly. Results of protein analyses of brain homogenates indicated that MIT treatment significantly decreased the tau phosphorylation implicated in tau toxicity (p < 0.05) and the expression of CKMT1 associated with mitochondrial dysfunction. Moreover, MIT significantly decreased the expression of two mitochondrial fusion-related proteins, Mfn2 and Opa1 (p < 0.01 for both), while increasing the expression of a mitophagy regulator, Parkin, suggesting a compensatory enhancement of mitophagy due to MIT-promoted mitochondrial fusion.

In conclusion, this study was the first to demonstrate the ability of an MIT nanoformulation to improve spatial memory in AD mice through its multi-targeting effects on Aβ production, tau phosphorylation, and mitochondrial dynamics. Thus, MIT may be a safe and effective therapeutic for AD.”

https://pubmed.ncbi.nlm.nih.gov/36830601/

“The results of the present study provide the first evidence that MIT nanoformulation containing melatonin, insulin, and THC has potential as a multi-targeting treatment for AD.”

https://www.mdpi.com/2218-273X/13/2/232

Regulatory role of the endocannabinoid system on glial cells toward cognitive function in Alzheimer’s disease: A systematic review and meta-analysis of animal studies

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“Objective: Over the last decade, researchers have sought to develop novel medications against dementia. One potential agent under investigation is cannabinoids. This review systematically appraised and meta-analyzed published pre-clinical research on the mechanism of endocannabinoid system modulation in glial cells and their effects on cognitive function in animal models of Alzheimer’s disease (AD). 

Methods: A systematic review complying with PRISMA guidelines was conducted. Six databases were searched: EBSCOHost, Scopus, PubMed, CINAHL, Cochrane, and Web of Science, using the keywords AD, cannabinoid, glial cells, and cognition. The methodological quality of each selected pre-clinical study was evaluated using the SYRCLE risk of bias tool. A random-effects model was applied to analyze the data and calculate the effect size, while I2 and p-values were used to assess heterogeneity. 

Results: The analysis included 26 original articles describing (1050 rodents) with AD-like symptoms. Rodents treated with cannabinoid agonists showed significant reductions in escape latency (standard mean difference [SMD] = -1.26; 95% confidence interval [CI]: -1.77 to -0.76, p < 0.00001) and ability to discriminate novel objects (SMD = 1.40; 95% CI: 1.04 to 1.76, p < 0.00001) compared to the control group. Furthermore, a significant decrease in Aβ plaques (SMD = -0.91; 95% CI: -1.55 to -0.27, p = 0.006) was observed in the endocannabinoid-treated group compared to the control group. Trends were observed toward neuroprotection, as represented by decreased levels of glial cell markers including glial fibrillary acid protein (SMD = -1.47; 95% CI: -2.56 to -0.38, p = 0.008) and Iba1 (SMD = -1.67; 95% CI: -2.56 to -0.79, p = 0.0002). Studies on the wild-type mice demonstrated significantly decreased levels of pro-inflammatory markers TNF-α, IL-1, and IL-6 (SMD = -2.28; 95% CI: -3.15 to -1.41, p = 0.00001). Despite the non-significant decrease in pro-inflammatory marker levels in transgenic mice (SMD = -0.47; 95% CI: -1.03 to 0.08, p = 0.09), the result favored the endocannabinoid-treated group over the control group. 

Conclusion: The revised data suggested that endocannabinoid stimulation promotes cognitive function via modulation of glial cells by decreasing pro-inflammatory markers in AD-like rodent models. Thus, cannabinoid agents may be required to modulate the downstream chain of effect to enhance cognitive stability against concurrent neuroinflammation in AD. Population-based studies and well-designed clinical trials are required to characterize the acceptability and real-world effectiveness of cannabinoid agents.”

https://pubmed.ncbi.nlm.nih.gov/36959856/

“Numerous traditional medical applications of cannabis have already been established and are now accepted practices in medicine.”

https://www.frontiersin.org/articles/10.3389/fphar.2023.1053680/full

Investigation of Cannabis sativa Phytochemicals as Anti-Alzheimer’s Agents: An In Silico Study

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“Cannabis sativa is a medicinal plant that has been known for years and is used as an Ayurvedic medicine. This plant has great potential in treating various types of brain diseases. Phytochemicals present in this plant act as antioxidants by maintaining synaptic plasticity and preventing neuronal loss.

Cannabidiol (CBD) and Tetrahydrocannabinol (THC) are both beneficial in treating Alzheimer’s disease by increasing the solubility of Aβ42 amyloid and Tau aggregation. Apart from these therapeutic effects, there are certain unknown functions of these phytochemicals in Alzheimer’s disease that we want to elucidate through this study.

In this research, our approach is to analyze the effect of phytochemicals in Cannabis sativa on multiple culprit enzymes in Alzheimer’s disease, such as AChE (Acetylcholinesterase), BChE (Butyrylcholinesterase), γ-secretase, and BACE-1. In this study, the compounds were selected by Lipinski’s rule, ADMET, and ProTox based on toxicity. Molecular docking between the selected compounds (THCV, Cannabinol C2, and Cannabidiorcol) and enzymes mentioned above was obtained by various software programs including AutoDock Vina 4.2, AutoDock, and iGEMDOCK.

In comparison to Donepezil (BA = -8.4 kcal/mol, Ki = 1.46 mM), Rivastigmine (BA = -7.0 kcal/mol, Ki = 0.02 mM), and Galantamine (BA = -7.1, Ki = 2.1 mM), Cannabidiorcol (BA = -9.4 kcal/mol, Ki = 4.61 mM) shows significant inhibition of AChE. On the other hand, Cannabinol C2 (BA = -9.2 kcal/mol, Ki = 4.32 mM) significantly inhibits Butyrylcholinesterase (BuChE) in comparison to Memantine (BA = -6.8 kcal/mol, Ki = 0.54 mM).

This study sheds new light and opens new avenues for elucidating the role of bioactive compounds present in Cannabis sativa in treating Alzheimer’s disease.”

https://pubmed.ncbi.nlm.nih.gov/36771595/

“In comparison to known drugs, THCV, Cannabinol C2 and Cannabidiorcol dominated cannabinoids’ inhibitory activities on AChE and BuChE. Computational approaches suggest that THCV, Cannabinol C2, and Cannabidiorcol are more appropriate for the inhibition of the enzymes AChE and BuChE, which act as the culprits of Alzheimer’s disease. Cell and animal studies are needed to improve the efficacy of these cannabinoids and to learn more about the effecting pathways.”

https://www.mdpi.com/2223-7747/12/3/510

Parkin Mediates Cannabidiol Prevention of Amyloid-Beta-Induced Senescence in Human Astrocytes

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“Introduction: As aging is the leading risk factor for Alzheimer’s disease (AD), ablation of senescent cells is a promising therapeutic approach to prevent AD. It is known that astrocytes lose their ability to maintain a healthy brain environment when aging. Studies have recently shown that cannabidiol (CBD) provides a promising therapeutic avenue for AD; however, if or how CBD prevents astrocyte aging is not known. 

Materials and Methods: In this study, human astrocytes were employed to measure amyloid-beta (Aβ)-induced senescence features, including senescence-associated β-galactosidase (SA-β-gal), p16INK4Ap21WAF1, and p53. The effects of CBD on the production of mitochondrial dysfunction and mitophagy pathway were measured by Western blot and fluorescence assay. Caenorhabditis elegans was used as in vivo AD model to investigate the effects of CBD on life span and health span. All experimental procedures were approved by the Human Research Ethics Committee, University of Wollongong, Australia. 

Results: In human astrocytes, we show that treatment with Aβ, an endogenous pathogenic agent of AD, results in an increase in the percentage of SA-β-gal-positive cells and induces mitochondrial reactive oxygen species (ROS). However, CBD treatment protects from Aβ-induced senescence. Furthermore, the anti-senescence and anti-apoptotic activities of CBD were observed to be mediated through the protective effect of Parkin-dependent mitophagy. In C. elegans, we used the transgenic GRU102 strain, which expresses the human Aβ peptide, and found that CBD treatment extended life span, improved pumping rate, and decreased mitochondrial ROS. 

Conclusion and Significance: Our results demonstrate that CBD prevents the human astrocyte senescence induced by Aβ by a mechanism involving the Parkin-mediated mitophagy pathway. Our findings support the new therapeutic avenues of CBD for the treatment of AD patients.”

https://pubmed.ncbi.nlm.nih.gov/36695672/

Hemp Protein Hydrolysates Modulate Inflammasome-Related Genes in Microglial Cells

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“A prolonged inflammatory response can lead to the development of neurodegenerative diseases such as Alzheimer’s disease. Enzymatic hydrolysis is a sustainable way to increase the value of protein sources by obtaining peptides that can exert bioactivity.

Hemp (Cannabis sativa L.) protein hydrolysates have been proven to exert anti-inflammatory activity.

In this study, two hemp protein hydrolysate (HPHs), obtained with Alcalase as sole catalyst, or with Alcalase followed by Flavourzyme, were evaluated as inflammatory mediators (TNFα, IL-1β, IL-6, and IL-10), microglial polarization markers (Ccr7iNosArg1, and Ym1), and genes related to inflammasome activation (Nlrp3AscCasp1, and Il18), employing the lipopolysaccharide (LPS)-induced neuroinflammation model in murine BV-2 microglial cells.

A significant decrease of the expression of proinflammatory genes (e.g., TnfαCcr7inos, and Nlrp3, among others) and increase of the expression anti-inflammatory cytokines in microglial cells was observed after treatment with the test HPHs. This result in the cell model suggests a polarization toward an anti-inflammatory M2 phenotype. Our results show that the evaluated HPHs show potential neuroprotective activity in microglial cells via the inflammasome.”

https://pubmed.ncbi.nlm.nih.gov/36671742/

“Neuroinflammation can lead to the development of neurodegenerative diseases. Food-derived peptides released by the action of enzymes have been proven to modulate several physiological processes. In this study, peptides obtained from hemp protein were evaluated as anti-inflammatory agents employing a cell model, measuring the responses of inflammatory mediators, microglial polarization markers, and genes related to inflammasome activation, as markers of inflammation and the potential counteraction exerted by the peptides, related to neurodegenerative processes. Results showed a neuroprotective effect based on anti-inflammatory activity of the peptides, via the inflammasome. The use of these peptides in the diet could help to prevent inflammation and promote a healthy aging of humans.”

https://www.mdpi.com/2079-7737/12/1/49

Oral THC: CBD cannabis extract in main symptoms of Alzheimer disease: agitation and weight loss

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“Objectives: Ten million new cases of dementia are recorded annually worldwide, with agitation and idiopathic weight loss being the most common symptoms. Several pharmacological therapies have emerged in recent years, but the clinical use of cannabis extracts in older patients with AD is constantly growing. This retrospective, analytical, observational, spontaneous trial aimed to enhance the clinical action of THC: CBD cannabis extract administration in AD patients with severe symptoms such as agitation, weight loss, cognitive impairment, and sleep disturbance.

Methods: Thirty patients (9 men and 21 women) diagnosed with mild, moderate, or severe AD, aged 65-90 years, appealing to our Second Opinion Medical Consultation (Modena, Italy), were enrolled and required to use oil-diluted cannabis extract, Bedrocan® (22% THC, 0.5% CBD, Olive Oil 50 ml), twice a day for 12 weeks. The efficacy of cannabinoid therapy was evaluated at baseline and 12 weeks after therapy, employing three self-administered questionnaires completed by the parents of the enrolled patients: NPI-Q, CMAI, and MMSE.

Key findings: The NPI-Q demonstrated a reduction (p<0.0001) in agitation, apathy, irritability, sleep disturbances, and eating disturbances, consequently improving caregiver distress. Levels of physically and verbally aggressive behaviours, measured using the CMAI questionnaire, were lower (p<0.0001) in all patients. The MMSSE questionnaire confirmed a significant decrease (p<0.0001) in cognitive impairment in 45% of the patients.

Conclusion: Our anecdotical, spontaneous, and observational study demonstrated the efficacy and safety of oil-diluted cannabis extract in patients with AD. The limitations of our study are: 1) small patient cohort, 2) absence of control group, 3) self-administered questionnaires that are the most practical but not objective instruments to assess the neurologic functions of AD patients.”

https://pubmed.ncbi.nlm.nih.gov/36655645/

Cannabinoids in neuroinflammatory disorders: Focusing on multiple sclerosis, Parkinsons, and Alzheimers diseases

“The medicinal properties of cannabis and cannabinoid-derivative are entirely investigated and known. In addition, the identification of psychotropic plant cannabinoids has led to more studies regarding the cannabinoid system and its therapeutic features in the treatment and management of clinical symptoms of neuroinflammatory disorders, such as multiple sclerosis (MS), Parkinsons disease (PD), and Alzheimers disease (AD). In fact, cannabinoid agonists are able to control and regulate inflammatory responses. In contrast to the cannabinoid receptor type 1 (CB1) and its unwanted adverse effects, the cannabinoid receptor type 2 (CB2) and its ligands hold promise for new and effective therapeutic approaches. So far, some successes have been achieved in this field. This review will discuss an outline of the endocannabinoid system’s involvement in neuroinflammatory disorders. Moreover, the pharmacological efficacy of different natural and synthetic preparations of phytocannabinoids acting on cannabinoid receptors, particularly in MS, PD, and AD, will be updated. Also, the reasons for targeting CB2 for neurodegeneration will be explained.”

https://pubmed.ncbi.nlm.nih.gov/36637897/

https://iubmb.onlinelibrary.wiley.com/doi/10.1002/biof.1936