Unraveling the Endocannabinoid System: Exploring Its Therapeutic Potential in Autism Spectrum Disorder

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“The salient features of autism spectrum disorder (ASD) encompass persistent difficulties in social communication, as well as the presence of restricted and repetitive facets of behavior, hobbies, or pursuits, which are often accompanied with cognitive limitations.

Over the past few decades, a sizable number of studies have been conducted to enhance our understanding of the pathophysiology of ASD. Preclinical rat models have proven to be extremely valuable in simulating and analyzing the roles of a wide range of established environmental and genetic factors.

Recent research has also demonstrated the significant involvement of the endocannabinoid system (ECS) in the pathogenesis of several neuropsychiatric diseases, including ASD. In fact, the ECS has the potential to regulate a multitude of metabolic and cellular pathways associated with autism, including the immune system. Moreover, the ECS has emerged as a promising target for intervention with high predictive validity.

Particularly noteworthy are resent preclinical studies in rodents, which describe the onset of ASD-like symptoms after various genetic or pharmacological interventions targeting the ECS, providing encouraging evidence for further exploration in this area.”



Cannabidiol and positive effects on object recognition memory in an in vivo model of Fragile X Syndrome: obligatory role of hippocampal GPR55 receptors

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“Cannabidiol (CBD), a non-psychotomimetic constituent of Cannabis sativa, has been recently approved for epileptic syndromes often associated with Autism spectrum disorder (ASD). However, the putative efficacy and mechanism of action of CBD in patients suffering from ASD and related comorbidities remain debated, especially because of the complex pharmacology of CBD. We used pharmacological, immunohistochemical and biochemical approaches to investigate the effects and mechanisms of action of CBD in the recently validated Fmr1-Δexon 8 rat model of ASD, that is also a model of Fragile X Syndrome (FXS), the leading monogenic cause of autism.

CBD rescued the cognitive deficits displayed by juvenile Fmr1-Δexon 8 animals, without inducing tolerance after repeated administration. Blockade of CA1 hippocampal GPR55 receptors prevented the beneficial effect of both CBD and the fatty acid amide hydrolase (FAAH) inhibitor URB597 in the short-term recognition memory deficits displayed by Fmr1-Δexon 8 rats. Thus, CBD may exert its beneficial effects through CA1 hippocampal GPR55 receptors. Docking analysis further confirmed that the mechanism of action of CBD might involve competition for brain fatty acid binding proteins (FABPs) that deliver anandamide and related bioactive lipids to their catabolic enzyme FAAH.

These findings demonstrate that CBD reduced cognitive deficits in a rat model of FXS and provide initial mechanistic insights into its therapeutic potential in neurodevelopmental disorders.”


“CBD improved cognition in a rat model of Fragile X Syndrome, the leading monogenic cause of autism.”


Early Administration of the Phytocannabinoid Cannabidivarin Prevents the Neurobehavioral Abnormalities Associated with the Fmr1-KO Mouse Model of Fragile X Syndrome

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“Phytocannabinoids, including the non-addictive cannabis component cannabidivarin (CBDV), have been reported to hold therapeutic potential in several neurodevelopmental disorders (NDDs). Nonetheless, the therapeutic value of phytocannabinoids for treating Fragile X syndrome (FXS), a major NDD, remains unexplored. Here, we characterized the neurobehavioral effects of CBDV at doses of 20 or 100 mg/kg in the Fmr1-knockout (Fmr1-KO) mouse model of FXS using two temporally different intraperitoneal regimens: subchronic 10-day delivery during adulthood (Study 1: rescue treatment) or chronic 5-week delivery at adolescence (Study 2: preventive treatment). Behavioral tests assessing FXS-like abnormalities included anxiety, locomotor, cognitive, social and sensory alterations. Expression of inflammatory and plasticity markers was investigated in the hippocampus and prefrontal cortex. When administered during adulthood (Study 1), the effects of CBDV were marginal, rescuing at the lower dose only the acoustic hyper-responsiveness of Fmr1-KO mice and at both doses their altered hippocampal expression of neurotrophins. When administered during adolescence (Study 2), CBDV at both doses prevented the cognitive, social and acoustic alterations of adult Fmr1-KO mice and modified the expression of several inflammatory brain markers in both wild-type littermates and mutants. These findings warrant the therapeutic potential of CBDV for preventing neurobehavioral alterations associated with FXS, highlighting the relevance of its early administration.”


“Overall, these data demonstrate that CBDV, when administered chronically and starting at juvenile age, holds a solid therapeutic potential for FXS as it prevented the most relevant behavioral alterations shown by Fmr1-KO mice.”


Role of the endocannabinoid system in fragile X syndrome: potential mechanisms for benefit from cannabidiol treatment

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“Multiple lines of evidence suggest a central role for the endocannabinoid system (ECS) in the neuronal development and cognitive function and in the pathogenesis of fragile X syndrome (FXS). This review describes the ECS, its role in the central nervous system, how it is dysregulated in FXS, and the potential role of cannabidiol as a treatment for FXS. FXS is caused by deficiency or absence of the fragile X messenger ribonucleoprotein 1 (FMR1) protein, FMRP, typically due to the presence of >200 cytosine, guanine, guanine sequence repeats leading to methylation of the FMR1 gene promoter. The absence of FMRP, following FMR1 gene-silencing, disrupts ECS signaling, which has been implicated in FXS pathogenesis. The ECS facilitates synaptic homeostasis and plasticity through the cannabinoid receptor 1, CB1, on presynaptic terminals, resulting in feedback inhibition of neuronal signaling. ECS-mediated feedback inhibition and synaptic plasticity are thought to be disrupted in FXS, leading to overstimulation, desensitization, and internalization of presynaptic CB1 receptors. Cannabidiol may help restore synaptic homeostasis by acting as a negative allosteric modulator of CB1, thereby attenuating the receptor overstimulation, desensitization, and internalization. Moreover, cannabidiol affects DNA methylation, serotonin 5HT1A signal transduction, gamma-aminobutyric acid receptor signaling, and dopamine D2 and D3 receptor signaling, which may contribute to beneficial effects in patients with FXS. Consistent with these proposed mechanisms of action of cannabidiol in FXS, in the CONNECT-FX trial the transdermal cannabidiol gel, ZYN002, was associated with improvements in measures of social avoidance, irritability, and social interaction, particularly in patients who are most affected, showing ≥90% methylation of the FMR1 gene.”


“FXS is caused by deficiency or absence of FMRP, typically due to the presence of >200 CGG repeats and methylation in the promoter region of the FMR1 gene. The absence of FMRP downregulates the ECS signaling, which has been implicated in FXS pathogenesis. Synaptic homeostasis and plasticity may be regulated by the ECS through the postsynaptic “on demand” production of endocannabinoids, which then bind to CB1 receptors on presynaptic terminals, resulting in regulation of glutamate signaling and GABAergic signaling. The ECS-mediated feedback inhibition and synaptic plasticity are thought to be disrupted in FXS due to dysregulation of enzymes that are integral to the ECS (e.g., DAGL), leading to overstimulation, desensitization, and internalization of presynaptic CB1 receptors.

Cannabidiol may help restore synaptic homeostasis by acting as a negative allosteric modulator of CB1, thereby attenuating CB1 receptor overstimulation, internalization, and desensitization. Moreover, cannabidiol has effects on DNA methylation, 5HT1A signal transduction, GABAA receptor signaling, and dopamine D2 and D3 receptor signaling, which may contribute to beneficial effects in patients with FXS. Consistent with these proposed mechanisms of action of cannabidiol in FXS, the transdermal cannabidiol gel, ZYN002, was associated with improvements in measures of social avoidance, irritability, and social interaction in the CONNECT-FX trial, particularly among patients with ≥90% methylation of the FMR1 gene.”


A randomized, controlled trial of ZYN002 cannabidiol transdermal gel in children and adolescents with fragile X syndrome (CONNECT-FX)

“Background: Fragile X syndrome (FXS) is associated with dysregulated endocannabinoid signaling and may therefore respond to cannabidiol therapy.

Design: CONNECT-FX was a double-blind, randomized phase 3 trial assessing efficacy and safety of ZYN002, transdermal cannabidiol gel, for the treatment of behavioral symptoms in children and adolescents with FXS.

Methods: Patients were randomized to 12 weeks of ZYN002 (250 mg or 500 mg daily [weight-based]) or placebo, as add-on to standard of care. The primary endpoint assessed change in social avoidance (SA) measured by the Aberrant Behavior Checklist-Community Edition FXS (ABC-CFXS) SA subscale in a full cohort of patients with a FXS full mutation, regardless of the FMR1 methylation status. Ad hoc analyses assessed efficacy in patients with ≥ 90% and 100% methylation of the promoter region of the FMR1 gene, in whom FMR1 gene silencing is most likely.

Results: A total of 212 patients, mean age 9.7 years, 75% males, were enrolled. A total of 169 (79.7%) patients presented with ≥ 90% methylation of the FMR1 promoter and full mutation of FMR1. Although statistical significance for the primary endpoint was not achieved in the full cohort, significant improvement was demonstrated in patients with ≥ 90% methylation of FMR1 (nominal P = 0.020). This group also achieved statistically significant improvements in Caregiver Global Impression-Change in SA and isolation, irritable and disruptive behaviors, and social interactions (nominal P-values: P = 0.038, P = 0.028, and P = 0.002). Similar results were seen in patients with 100% methylation of FMR1. ZYN002 was safe and well tolerated. All treatment-emergent adverse events (TEAEs) were mild or moderate. The most common treatment-related TEAE was application site pain (ZYN002: 6.4%; placebo: 1.0%).

Conclusions: In CONNECT-FX, ZYN002 was well tolerated in patients with FXS and demonstrated evidence of efficacy with a favorable benefit risk relationship in patients with ≥ 90% methylation of the FMR1 gene, in whom gene silencing is most likely, and the impact of FXS is typically most severe.”



Parent and Caregiver Perspectives towards Cannabidiol as a Treatment for Fragile X Syndrome


“Cannabidiol (CBD) is a non-intoxicating chemical in cannabis plants that is being investigated as a candidate for treatment in Fragile X Syndrome (FXS), a leading known cause of inherited intellectual developmental disability. Studies have shown that CBD can reduce symptoms such as anxiety, social avoidance, hyperactivity, aggression, and sleep problems. This is a qualitative study that utilized a voluntary-anonymous survey that consisted of questions regarding demographics, medical information, the form, type, brand, dose, and frequency of CBD use, the rationale for use, the perception of effects, side effects, and costs. The full survey contained a total of 34 questions, including multiple-choice, Likert-scale, and optional free-response questions. This research revealed that there are a wide range of types, brands, and doses of CBD being administered to individuals with FXS by their parents and caregivers. There were many reasons why CBD was chosen, the most common ones being that respondents had heard positive things about CBD from members of the community, the perception that CBD had fewer side effects than other medications, and because respondents felt that CBD was a more natural substance. Most of the parents and caregivers who responded agreed that CBD improved some of the symptoms of FXS and made a positive difference overall. CBD has the therapeutic potential to help relieve some FXS symptoms. Future research is necessary to understand the benefits of CBD in FXS.”



The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

ijms-logo“The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems.

In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development.

The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development.

The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases.

This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as “C. sativa L.” or “medical cannabis”), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.”




“Cannabis sativa L. as a Natural Drug Meeting the Criteria of a Multitarget Approach to Treatment”


Possible therapeutic applications of cannabis in the neuropsychopharmacology field.

European Neuropsychopharmacology“Cannabis use induces a plethora of actions on the CNS via its active chemical ingredients, the so-called phytocannabinoids.

These compounds have been frequently associated with the intoxicating properties of cannabis preparations. However, not all phytocannabinoids are psychotropic, and, irrespective of whether they are psychotropic or not, they have also shown numerous therapeutic properties.

These properties are mostly associated with their ability to modulate the activity of an intercellular communication system, the so-called endocannabinoid system, which is highly active in the CNS and has been found altered in many neurological disorders.

Specifically, this includes the neuropsychopharmacology field, with diseases such as schizophrenia and related psychoses, anxiety-related disorders, mood disorders, addiction, sleep disorders, post-traumatic stress disorder, anorexia nervosa and other feeding-related disorders, dementia, epileptic syndromes, as well as autism, fragile X syndrome and other neurodevelopment-related disorders.

Here, we gather, from a pharmacological and biochemical standpoint, the recent advances in the study of the therapeutic relevance of the endocannabinoid system in the CNS, with especial emphasis on the neuropsychopharmacology field. We also illustrate the efforts that are currently being made to investigate at the clinical level the potential therapeutic benefits derived from elevating or inhibiting endocannabinoid signaling in animal models of neuropsychiatric disorders.”



Effects of CBD-Enriched Cannabis sativa Extract on Autism Spectrum Disorder Symptoms: An Observational Study of 18 Participants Undergoing Compassionate Use.

Image result for frontiers in neurology“Autism Spectrum Disorders comprise conditions that may affect cognitive development, motor skills, social interaction, communication, and behavior. This set of functional deficits often results in lack of independence for the diagnosed individuals, and severe distress for patients, families, and caregivers.

There is a mounting body of evidence indicating the effectiveness of pure cannabidiol (CBD) and CBD-enriched Cannabis sativa extract (CE) for the treatment of autistic symptoms in refractory epilepsy patients. There is also increasing data support for the hypothesis that non-epileptic autism shares underlying etiological mechanisms with epilepsy.

Here we report an observational study with a cohort of 18 autistic patients undergoing treatment with compassionate use of standardized CBD-enriched CE (with a CBD to THC ratio of 75/1).

Among the 15 patients who adhered to the treatment (10 non-epileptic and five epileptic) only one patient showed lack of improvement in autistic symptoms. Due to adverse effects, three patients discontinued CE use before 1 month.

After 6-9 months of treatment, most patients, including epileptic and non-epileptic, showed some level of improvement in more than one of the eight symptom categories evaluated: Attention Deficit/Hyperactivity Disorder; Behavioral Disorders; Motor Deficits; Autonomy Deficits; Communication and Social Interaction Deficits; Cognitive Deficits; Sleep Disorders and Seizures, with very infrequent and mild adverse effects.

The strongest improvements were reported for Seizures, Attention Deficit/Hyperactivity Disorder, Sleep Disorders, and Communication and Social Interaction Deficits. This was especially true for the 10 non-epileptic patients, nine of which presented improvement equal to or above 30% in at least one of the eight categories, six presented improvement of 30% or more in at least two categories and four presented improvement equal to or above 30% in at least four symptom categories.

Ten out of the 15 patients were using other medicines, and nine of these were able to keep the improvements even after reducing or withdrawing other medications.

The results reported here are very promising and indicate that CBD-enriched CE may ameliorate multiple ASD symptoms even in non-epileptic patients, with substantial increase in life quality for both ASD patients and caretakers.”


“The findings presented here, taken together, support the notion that many autism symptoms are associated to neuronal hyperexcitability, and indicate that CBD-enriched CE yields positive effects in multiple autistic symptoms, without causing the typical side effects found in medicated ASD patients. Most patients in this study had improved symptoms even after supervised weaning of other neuropsychiatric drugs.”


A phase 1/2, open-label assessment of the safety, tolerability, and efficacy of transdermal cannabidiol (ZYN002) for the treatment of pediatric fragile X syndrome.


Image result for journal of neurodevelopmental disorders“Fragile X syndrome (FXS) is characterized by a range of developmental, neuropsychiatric, and behavioral symptoms that cause significant impairment in those with the disorder.

Cannabidiol (CBD) holds promise as a potential treatment for FXS symptoms due to its safety profile and positive effects on a number of emotional and behavioral symptoms associated with FXS.

The aim of the current study was to evaluate the safety, tolerability, and initial efficacy of ZYN002, a transdermal CBD gel, in a pediatric population with FXS.


The majority of treatment-emergent AEs (reported by 85% of participants) were mild in severity (70%), and no serious adverse events were reported. There was a statistically significant reduction in ADAMS total score from screening to week 12 and significant reductions on nearly all other secondary endpoints, including all ADAMS subscales (except depressed mood), all ABC-CFXS subscale scores (e.g., social avoidance, irritability), PARS-R total severity score, and PedsQL total score.


ZYN002 was well tolerated and produced clinically meaningful reductions in anxiety and behavioral symptoms in children and adolescents with FXS. These findings support further study of ZYN002 in a randomized, well-controlled trial for the treatment of behavioral symptoms of FXS.”