Effects of Cannabidiol and Beta-Caryophyllene Alone or in Combination in a Mouse Model of Permanent Ischemia

Cannabidiol in experimental cerebral ischemia

The absence of blood flow in cerebral ischemic conditions triggers a multitude of intricate pathophysiological mechanisms, including excitotoxicity, oxidative stress, neuroinflammation, disruption of the blood-brain barrier and white matter disarrangement. Despite numerous experimental studies conducted in preclinical settings, existing treatments for cerebral ischemia (CI), such as mechanical and pharmacological therapies, remain constrained and often entail significant side effects. Therefore, there is an imperative to explore innovative strategies for addressing CI outcomes. Cannabidiol (CBD), the most abundant non-psychotomimetic compound derived from Cannabis sativa, is a pleiotropic substance that interacts with diverse molecular targets and has the potential to influence various pathophysiological processes, thereby contributing to enhanced outcomes in CI. This chapter provides a comprehensive overview of the primary effects of CBD in in vitro and diverse animal models of CI and delves into some of its plausible mechanisms of neuroprotection.

Anti-Inflammatory Properties of Cannabidiol and Beta-Caryophyllene Alone or Combined in an In Vitro Inflammation Model

Cannabis contains over 500 different compounds, including cannabinoids, terpenoids, and flavonoids. Cannabidiol (CBD) is a non-psychoactive constituent, whereas beta-caryophyllene (BCP) is one of most the well-known terpenoids of Cannabis sativa. In recent years, there has been an emerging idea that the beneficial activities of these compounds are greater when they are combined. The aim of this study was to evaluate the anti-inflammatory effect of CBD and BCP using the in vitro model of lipopolysaccharide (LPS)-stimulated human keratinocytes (HaCaT) cells. The vitality of the cells was quantified using LDH and MTT assays. The levels of the following pro-inflammatory proteins and genes were quantified: IL-1β, COX-2, and phospho-NF-κB p65 (p-p65) through Western blotting (WB) and interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNFα) through quantitative real-time polymerase chain reaction (RT-qPCR). When present in the incubation medium, CBD and BCP reduced the increased levels of pro-inflammatory proteins (IL-1β, COX-2, and p-NF-kB) induced by LPS. The anti-inflammatory effects of CBD were blocked by a PPARγ antagonist, whereas a CB2 antagonist was able to revert the effects of BCP. Selected concentrations of CBD and BCP were able to revert the increases in the expression of pro-inflammatory genes (IL-1β, IL-6, and TNFα), and these effects were significant when the drugs were used in combination. Our results suggest that CBD and BCP work in concert to produce a major anti-inflammatory effect with good safety profiles.

Pharmacological Evaluation of Newly Synthesized Cannabidiol Derivates on H9c2 Cells

Cannabidiol (CBD) is a nonpsychoactive phytocannabinoid that can be found in Cannabis sativa and possesses numerous pharmacological effects. Due to these promising effects, CBD can be used in a wide variety of diseases, for instance cardiovascular diseases. However, CBD, like tetrahydrocannabinol (THC), has low bioavailability, poor water solubility, and a variable pharmacokinetic profile, which hinders its therapeutic use. Chemical derivatization of CBD offers us potential ways to overcome these issues. We prepared three new CBD derivatives substituted on the aromatic ring by Mannich-type reactions, which have not been described so far for the modification of cannabinoids, and studied the protective effect they have on cardiomyocytes exposed to oxidative stress and hypoxia/reoxygenation (H/R) compared to the parent compound. An MTT assay was performed to determine the viability of rat cardiomyocytes treated with test compounds. Trypan blue exclusion and lactate dehydrogenase (LDH) release assays were carried out to study the effect of the new compounds in cells exposed to H2O2 or hypoxia/reoxygenation (H/R). Direct antioxidant activity was evaluated by a total antioxidant capacity (TAC) assay. To study antioxidant protein levels, HO-1, SOD, catalase, and Western blot analysis were carried out. pIC50 (the negative log of the IC50) values were as follows: CBD1: 4.113, CBD2: 3.995, CBD3: 4.190, and CBD: 4.671. The newly synthesized CBD derivatives prevented cell death induced by H/R, especially CBD2. CBD has the largest direct antioxidant activity. The levels of antioxidant proteins were increased differently after pretreatment with synthetic CBD derivatives and CBD. Taken together, our newly synthesized CBD derivatives are able to decrease cytotoxicity during oxidative stress and H/R. The compounds have similar or better effects than CBD on H9c2 cells.

Pharmacological Studies on Neuromodulatory Effects of Plant Extracts

Central nervous system (CNS) disorders represent a public health priority and demand significant scientific efforts for the development and study of new drugs and their possible beneficial effects [...].

Disease-modifying effects of cannabidiol, β-caryophyllene and their combination in Syn1-Cre/Scn1aWT/A1783V mice, a preclinical model of Dravet syndrome

Cannabidiol (CBD) has been recently approved as an antiseizure agent in Dravet Syndrome (DS), a pediatric epileptic encephalopathy, but CBD could also be active against associated comorbidities. Such associated comorbidities were also attenuated by the sesquiterpene β-caryophyllene (BCP). Here, we have compared the efficacy of both compounds and further initiated the analysis of a possible additive effect between both compounds in relation with these comorbidities using two experimental approaches. The first experiment was aimed at comparing the benefits of CBD and BCP, including their combination in conditional knock-in Scn1a-A1783V mice, an experimental model of DS, treated since the postnatal day 10th to 24th. As expected, DS mice showed impairment in limb clasping, delay in the appearance of hindlimb grasp reflex and additional behavioural disturbances (e.g., hyperactivity, cognitive deterioration, social interaction deficits). This behavioural impairment was associated with marked astroglial and microglial reactivities in the prefrontal cortex and the hippocampal dentate gyrus. BCP and CBD administered alone were both able to partially attenuate the behavioural disturbances and the glial reactivities, with apparently greater efficacy against glial reactivities obtained with BCP, whereas superior effects in a few specific parameters were obtained when both compounds were combined. In the second experiment, we investigated this additive effect in cultured BV2 cells treated with BCP and/or CBD and stimulated with LPS. As expected, addition of LPS induced a marked increase in several inflammation-related markers (e.g., TLR4, COX-2, iNOS, catalase, TNF-α, IL-1β), as well as elevated Iba-1 immunostaining. Treatment with BCP or CBD attenuated these elevations, but, again and in general, superior results were obtained when both cannabinoids were combined. In conclusion, our results support the interest to continue investigating the combination of BCP and CBD to improve the therapeutic management of DS in relation with their disease-modifying properties.

Cannabidiol’s Multifactorial Mechanisms Has Therapeutic Potential for Aneurysmal Subarachnoid Hemorrhage: a Review

Subarachnoid hemorrhage (SAH) is a major health burden that accounts for approximately 5% of all strokes. The most common cause of a non-traumatic SAH is the rupture of a cerebral aneurysm. The most common symptom associated with SAH is a headache, often described as “the worst headache of my life.” Delayed cerebral ischemia (DCI) is a major factor associated with patient mortality following SAH and is often associated with SAH-induced cerebral vasospasm (CV). Cannabidiol (CBD) is emerging as a potential drug for many therapeutic purposes, including epilepsy, anxiety, and pain relief. We aim to review the potential use of CBD as a treatment option for post-SAH critically ill patients. Through a literature review, we evaluated the known pharmacology and physiological effects of CBD and correlated those with the pathophysiological outcomes associated with cerebral vasospasm following subarachnoid hemorrhage. Although overlap exists, data were formatted into three major categories: anti-inflammatory, vascular, and neuroprotective effects. Based on the amount of information known about the actions of CBD, we hypothesize the anti-inflammatory effects are likely to be the most promising therapeutic mechanism. However, its cardiovascular effects through calcium regulation and its neuroprotective effects against cell death, excitotoxicity, and oxidative stress are all plausible mechanisms by which post-SAH critically ill patients may benefit from both early and late intervention with CBD. More research is needed to better understand if and how CBD might affect neurological and vascular functions in the brain following injury such as subarachnoid hemorrhage.

Neuroprotection of Cannabidiol, Its Synthetic Derivatives and Combination Preparations against Microglia-Mediated Neuroinflammation in Neurological Disorders

The lack of effective treatment for neurological disorders has encouraged the search for novel therapeutic strategies. Remarkably, neuroinflammation provoked by the activated microglia is emerging as an important therapeutic target for neurological dysfunction in the central nervous system. In the pathological context, the hyperactivation of microglia leads to neuroinflammation through the release of neurotoxic molecules, such as reactive oxygen species, proteinases, proinflammatory cytokines and chemokines. Cannabidiol (CBD) is a major pharmacologically active phytocannabinoids derived from Cannabis sativa L. CBD has promising therapeutic effects based on mounting clinical and preclinical studies of neurological disorders, such as epilepsy, multiple sclerosis, ischemic brain injuries, neuropathic pain, schizophrenia and Alzheimer’s disease. A number of preclinical studies suggested that CBD exhibited potent inhibitory effects of neurotoxic molecules and inflammatory modulators, highlighting its remarkable therapeutic potential for the treatment of numerous neurological disorders. However, the molecular mechanisms of action underpinning CBD’s effects on neuroinflammation appear to be complex and are poorly understood. This review summarises the anti-neuroinflammatory activities of CBD against various neurological disorders with a particular focus on their main molecular mechanisms of action, which were related to the downregulation of NADPH oxidase-mediated ROS, TLR4-NFκB and IFN-β-JAK-STAT pathways. We also illustrate the pharmacological action of CBD’s derivatives focusing on their anti-neuroinflammatory and neuroprotective effects for neurological disorders. We included the studies that demonstrated synergistic enhanced anti-neuroinflammatory activity using CBD and other biomolecules. The studies that are summarised in the review shed light on the development of CBD, including its derivatives and combination preparations as novel therapeutic options for the prevention and/or treatment of neurological disorders where neuroinflammation plays an important role in the pathological components.

Cannabinoids as Glial Cell Modulators in Ischemic Stroke: Implications for Neuroprotection

Stroke is the second leading cause of death worldwide following coronary heart disease. Despite significant efforts to find effective treatments to reduce neurological damage, many patients suffer from sequelae that impair their quality of life. For this reason, the search for new therapeutic options for the treatment of these patients is a priority. Glial cells, including microglia, astrocytes and oligodendrocytes, participate in crucial processes that allow the correct functioning of the neural tissue, being actively involved in the pathophysiological mechanisms of ischemic stroke. Although the exact mechanisms by which glial cells contribute in the pathophysiological context of stroke are not yet completely understood, they have emerged as potentially therapeutic targets to improve brain recovery. The endocannabinoid system has interesting immunomodulatory and protective effects in glial cells, and the pharmacological modulation of this signaling pathway has revealed potential neuroprotective effects in different neurological diseases. Therefore, here we recapitulate current findings on the potential promising contribution of the endocannabinoid system pharmacological manipulation in glial cells for the treatment of ischemic stroke.

In vivo tissue optical clearing assisted through-skull targeted photothrombotic ischemic stroke model in mice

SIGNIFICANCE

Photothrombotic stroke is an important and widely used model for ischemic stroke research. However, the significant scattering of the skull during the procedure limits the light's ability to penetrate and focus on its target. Targeted photothrombosis uses surgery-based skull windows to obtain optical access to the brain, but it renders the brain's environment unnatural even before a stroke is established.

AIM

To establish a targeted, controllable ischemic stroke model in mice through an intact skull.

APPROACH

The in vivo skull optical clearing technique provides a craniotomy-free "optical window" that allows light to penetrate. Alongside the local photodynamic effect, we have established targeted photothrombosis without skull removal, effectively controlling the degree of thrombotic occlusion by changing the light dose.

RESULTS

Ex vivo and in vivo results demonstrated that skull optical clearing treatment significantly enhanced light's ability to penetrate the skull and focus on its target, contributing to thrombotic occlusion. The skull optical clearing window was also used for continuous blood flow mapping, and the relationship between light dose and injury degree was evaluated over 14 days of monitoring. Per our findings, increasing the light dose was accompanied by more severe infarction, indicating that the model was easily controllable.

CONCLUSIONS

Herein, a targeted, controllable ischemic stroke model was established by combinedly running an in vivo skull optical clearing technique and a photothrombotic procedure, avoiding unnecessary damage or environmental changes to the brain caused by surgery on the skull. Our established model should offer significant value to research on ischemic stroke.