“Parkinson’s disease (PD) is a neurodegenerative disease and its characteristic is the progressive degeneration of dopaminergic neurons within the substantia nigra (SN) of the midbrain. There is hardly any clinically proven efficient therapeutics for its cure in several recent preclinical advances proposed to treat PD.
Recent studies have found that the endocannabinoid signaling system in particular the comprised two receptors, CB1 and CB2 receptors, has a significant regulatory function in basal ganglia and is involved in the pathogenesis of PD. Therefore, adding new insights into the biochemical interactions between cannabinoids and other signaling pathways may help develop new pharmacological strategies.
Factors of the endocannabinoid system (ECS) are abundantly expressed in the neural circuits of basal ganglia, where they interact interactively with glutamatergic, γ-aminobutyric acid-ergic (GABAergic), and dopaminergic signaling systems. Although preclinical studies on PD are promising, the use of cannabinoids at the clinical level has not been thoroughly studied.
In this review, we evaluated the available evidence and reviewed the involvement of ECS in etiologies, symptoms and treatments related to PD. Since CB1 and CB2 receptors are the two main receptors of endocannabinoids, we primarily put the focus on the therapeutic role of CB1 and CB2 receptors in PD. We will try to determine future research clues that will help understand the potential therapeutic benefits of the ECS in the treatment of PD, aiming to open up new strategies and ideas for the treatment of PD.”
“The basal ganglia (BG), an organized network of nuclei that integrates cortical information, play a crucial role in controlling motor function. In fact, movement disorders such as Parkinson’s disease (PD) and Huntington’s disease (HD) are caused by the degeneration of specific structures within the BG.
There is substantial evidence supporting the idea that cannabinoids may constitute novel promising compounds for the treatment of movement disorders as neuroprotective and anti-inflammatory agents.
This potential therapeutic role of cannabinoids is based, among other qualities, on their capacity to reduce oxidative injury and excitotoxicity, control calcium influx and limit the toxicity of reactive microglia.
The mechanisms involved in these effects are related to CB1 and CB2 receptor activation, although some of the effects are CB receptor independent.
Thus, taking into account the aforementioned properties, compounds that act on the endocannabinoid system could be useful as a basis for developing disease-modifying therapies for PD and HD.”
“In a recent study, we described the neuroprotective properties of VCE-003.2-an aminoquinone derivative of the non-psychotropic phytocannabinoid cannabigerol (CBG)-administered intraperitoneally (i.p.) in an inflammatory model of Parkinson’s disease (PD). We also demonstrated that these properties derive from its activity on the peroxisome proliferator-activated receptor-γ, in particular at a regulatory site within this receptor type.
In the present study, we wanted to further confirm this neuroprotective potential using an oral lipid formulation of VCE-003.2, developed to facilitate the clinical development of this phytocannabinoid derivative.
To this end, we evaluated VCE-003.2, administered orally at two doses (10 and 20 mg/kg), to mice subjected to unilateral intrastriatal injections of lipopolysaccharide (LPS), a classic model of inflammation-driven neuronal deterioration that recapitulates characteristics of PD.
In summary, our data confirm the neuroprotective potential of an oral formulation of VCE-003.2 against neuronal injury in an in vivo model of PD based on neuroinflammation, and this study opens the possibility to further the development of oral VCE-003.2 in the clinic.”
“The endocannabinoid system plays a regulatory role in a number of physiological functions, including motor control but also mood, emotion, and cognition.
A number of preclinical studies in Parkinson’s disease (PD) models demonstrated that modulating the type 1 cannabinoid receptor (CB1R) may improve motor symptoms and components of cognitive processing. However, the relation between CB1R, cognitive decline and behavioral symptoms has not been investigated in PD patients so far.
The aim of this study was to examine whether CB1R availability is associated with measures of cognitive and behavioral function in PD patients.
Decreased CB1R availability in the prefrontal and midcingulate cortex in PD patients is strongly correlated with disturbances in executive functioning, episodic memory, and visuospatial functioning. Further investigation of regional CB1R expression in groups of PD patients with mild cognitive impairment or dementia is warranted in order to further investigate the role of CB1R expression in different levels of cognitive impairment in PD.”
“Current pharmacotherapy of Parkinson’s disease (PD) is palliative and unable to modify the progression of neurodegeneration. Treatments that can improve patients’ quality of life with fewer side effects are needed, but not yet available.
Cannabidiol (CBD), the major non-psychotomimetic constituent of cannabis, has received considerable research attention in the last decade. In this context, we aimed to critically review the literature on potential therapeutic effects of CBD in PD and discuss clinical and preclinical evidence supporting the putative neuroprotective mechanisms of CBD.
Few studies addressed the biological bases for the purported effects of CBD on PD. Six preclinical studies showed neuroprotective effects, while three targeted the antidyskinetic effects of CBD. Three human studies have tested CBD in patients with PD: an open-label study, a case series, and a randomized controlled trial. These studies reported therapeutic effects of CBD on non-motor symptoms.
Additional research is needed to elucidate the potential effectiveness of CBD in PD and the underlying mechanisms involved.”
“Cannabis and synthetic cannabinoid formulations have now been legally approved in several countries for treatment of patients with Parkinson’s disease (PD). Hence, PD patients consult physicians more frequently for prescription of cannabinoids to alleviate symptoms that might not respond well to dopaminergic treatment. Despite the increasing volume of research generated in the field of cannabinoids and their effect on Parkinson’s disease, there is still paucity of sufficient clinical data about the efficacy and safety in PD patients. There is increasing understanding of the endocannabinoid system, and the distribution of cannabinoid receptors in basal ganglia structures might suggest potential benefit on parkinsonian symptoms. Concerning clinical research, only one of to date four conducted randomized placebo-controlled trials showed an effect on motor symptoms with alleviation of levodopa-induced dyskinesia. There are a growing number of uncontrolled trials and case reports that suggest beneficial effects of cannabinoids in PD patients. However, the variety of substances investigated, the varying routes of intake, differing doses and time courses make it difficult to compare data. We here provide an overview of the current literature in this field and discuss a pragmatic approach for the clinical use of cannabinoids in PD.”
“Although open-label observations report a positive effect of cannabinoids on non-motor symptoms (NMS) in Parkinson’s disease (PD) patients, these effects remain to be investigated in a controlled trial for a broader use in NMS in PD patients. Therefore, we decided to design a proof-of-concept study to assess the synthetic cannabinoid nabilone for the treatment of NMS. We hypothesize that nabilone will improve NMS in patients with PD and have a favorable safety profile. The NMS-Nab Study is as a mono-centric phase II, randomized, placebo-controlled, double-blind, parallel-group, enriched enrollment withdrawal study. The primary efficacy criterion will be the change in Movement Disorders Society-Unified Parkinson’s Disease-Rating Scale Part I score between baseline (i.e. randomization) and week 4. A total of 38 patients will have 80% power to detect a probability of 0.231 that an observation in the treatment group is less than an observation in the placebo group using a Wilcoxon rank-sum test with a 0.050 two-sided significance level assuming a true difference of 2.5 points between nabilone and placebo in the primary outcome measure and a standard deviation of the change of 2.4 points. The reduction of harm through an ineffective treatment, the possibility of individualized dosing, the reduction of sample size, and the possible evaluation of the influence of the placebo effect on efficacy outcomes justify this design for a single-centered placebo-controlled investigator-initiated trial of nabilone. This study should be the basis for further evaluations of long-term efficacy and safety of the use of cannabinoids in PD patients.”
“Marijuana is popular in the United States and is being widely legalized for recreational and medicinal purposes. It remains a Schedule 1 substance without fully proven risks and benefits; yet, it is increasingly available in many US states and territories.
Cannabis might have medicinal efficacy in Parkinson’s disease as a form of medical marijuana. Endocannabinoid receptors exist throughout the nervous system and are documented to influence receptors affecting a wide variety of areas. Neuroprotective aspects might be induced by cannabis exposure that might yield benefit against the nigrostriatal degeneration of patients with Parkinson’s disease.
Animal investigations support suggestions of improvement in bradykinesia and/or tremors, but this is unsubstantiated in human studies. However, some patient surveys and anecdotal or case reports indicate that marijuana attenuates some motor manifestations of parkinsonism and also of non-motor, mood and/or cognitive symptoms. Medical marijuana might benefit motor and nonmotor aspects of Parkinson’s disease patients. Currently, these assertions are not substantiated in human investigations and cannabis can also induce side effects. Until studies clarify the safety and efficacy of pharmacotherapy with cannabis products, medical marijuana remains largely without scientific endorsement. Research has yet to document the full benefits, risks, and clinical applications of marijuana as a treatment for patients with Parkinson’s disease.”
“Legalization of the medical use of cannabis for Parkinson’s disease (PD) has bypassed the traditional drug-approval process, leaving physicians with little evidence with which to guide patients.
The goal of this study was to gather data on the cannabis-related prescribing practices and views regarding potential risks and benefits of cannabis among experts caring for patients with PD.
An anonymous, 73-item online survey was conducted through an online service (SurveyMonkey) and included neurologists at all National Parkinson Foundation Centers of Excellence.
Fifty-six responders represented centers across 5 countries and 14 states. 23% reported some formal education on cannabis. Eighty percent of responders had patients with PD who used cannabis, and 95% were asked to prescribe it. Fifty-two percent took a neutral position on cannabis use with their patients, 9% discouraged use, and 39% encouraged it. Most believed that the literature supported use of cannabis for nausea (87%; n = 48), anxiety (60%; n = 33), and pain (86%; n = 47), but responses were divided with regard to motor symptoms. Most respondents expected that cannabis would worsen motivation (59%; n = 32), sleepiness (60%; n = 31), and hallucinations (69%; n = 37). In addition, most feared negative effects on short-term memory (75%; n = 42), long-term memory (55%; n = 31), executive functioning (79%; n = 44), and driving (96%; n = 54). Although many did not believe that cannabis should be recreational (50%; n = 28), most believed that it should be legalized for medicinal purposes (69.6%; n = 39).
This study provides data on the cannabis-related practices, beliefs, and attitudes of expert PD physicians. There is a lack of consensus that likely reflects a general knowledge gap and paucity of data to guide clinical practice.”
“Parkinson’s disease (PD) is a chronic neurodegenerative disorder characterized by motor symptoms such as bradykinesia, rest tremor, postural disturbances, and rigidity. PD is also characterized by non-motor symptoms such as sleep disturbances, cognitive deficits, and psychiatric disorders such as psychosis, depression, and anxiety. The pharmacological treatment for these symptoms is limited in efficacy and induce significant adverse reactions, highlighting the need for better treatment options.
Cannabidiol (CBD) is a phytocannabinoid devoid of the euphoriant and cognitive effects of tetrahydrocannabinol, and preclinical and preliminary clinical studies suggest that this compound has therapeutic effect in non-motor symptoms of PD.
In the present text, we review the clinical studies of cannabinoids in PD and the preclinical and clinical studies specifically on CBD.
We found four randomized controlled trials (RCTs) involving the administration of agonists/antagonists of the cannabinoid 1 receptor, showing that these compounds were well tolerated, but only one study found positive results (reductions on levodopa-induced dyskinesia).
We found seven preclinical models of PD using CBD, with six studies showing a neuroprotective effect of CBD.
We found three trials involving CBD and PD: an open-label study, a case series, and an RCT. CBD was well tolerated, and all three studies reported significant therapeutic effects in non-motor symptoms (psychosis, rapid eye movement sleep behaviour disorder, daily activities, and stigma). However, sample sizes were small and CBD treatment was short (up to 6 weeks). Large-scale RCTs are needed to try to replicate these results and to assess the long-term safety of CBD.”