Endocannabinoid system, pharmacogenomics and response to therapy

Short and long term effects of Nabiximols on balance and walking assessed by 3D-gait analysis in people with Multiple Sclerosis and spasticity

BACKGROUND

Spasticity in people with Multiple Sclerosis (pwMS) is one of the most disabling symptoms on walking ability and balance. Among the systemic antispastic drugs, Nabiximols showed a good tolerability, safety profile and relevant efficacy. A few studies assessed long-term effects of this drug through clinical scales and instrumental tools, but no study investigated short-term effects. The aim of our study is to quantitatively evaluate the immediate effects of Nabiximols on walking and balance and their maintenance after 4 weeks in pwMS and spasticity.

METHODS

pwMS were enrolled and randomized in 2 treatment groups: Sativex (SG) and control (CG) group. All patients were assessed at T0 (before the first Sativex puff), T1(after 45 minutes) and T2 (after 4 weeks of treatment) using clinical scales and 3d-Gait Analysis . Then, the patients treated with Sativex, were divided into 5 subgroups according to Numeric Rating Scale for spasticity (NRSs) and Berg Balance Score (BBS) response: NRSs responder[1] and non-[2]; BBS responders[3] and non-[4]; NRSs-BBS responders[5].

RESULTS

32 pwMS (22 SG, 10 CG) were recruited. Significant improvements were found between T0 and T1 in SG compared to CG in a few clinical and kinematic parameters. Larger significant differences were found for NRSs and BBS responders' groups versus CG. Eventually, no significant differences were found comparing the results between T1 and T2, suggesting the persistence of the improvements emerged at T1.

CONCLUSION

These results quantitatively demonstrated a short time effect of Nabiximols on balance and walking of pwMS, which is mantained after 4 weeks. Patients identified as responder by combination of NRSs and BBS showed the best efficacy. These findings may suggest how to early select the real responders in order to improve the adherence and cost-effectiveness of the therapy.

Psychiatric Disorders and Cannabinoid Receptors

With the increasing global use of medical and adult recreational use of cannabis and cannabinoids, this chapter provides overview of evidence from animal and human studies on psychiatric disorders and cannabinoid receptors. We review and present evaluation of the relationship between changes in the ECS and psychiatric disorders. Evidence suggests the existence of a relationship between changes in components of the ECS, and some of the symptoms present in psychiatric disorders. Both CB1Rs and CB2Rs are components of the endocannabinoid system with different cellular and tissue localization patterns that are differentially expressed in the CNS and PNS and are emerging targets for the treatment of number psychiatric disorders. As cannabis preparations are widely used for recreation globally, it is predictable that cannabis use disorders (CUDs) will increase and there is currently no available treatment for CUDs. Although major advances have been reported from cannabinoid and ECS research, there are gaps in scientific knowledge on long-term consequences of cannabis use. Adolescent and cannabis use during pregnancy presents further challenges, and more research will uncover the signaling pathways that couple the gut microbiota with the host ECS. Development of cannabis and cannabinoid nanomedicine for nanotherapy will certainly overcome some of the shortcomings and challenges in medicinal and recreational use of cannabis and cannabinoids. Thus, nanotechnology will allow targeted delivery of cannabinoid formulations with the potential to elevate their use to scientifically validated nanotherapeutic applications as the field of cannabis nanoscience matures.

Cannabinoid Receptors: An Update on Cell Signaling, Pathophysiological Roles and Therapeutic Opportunities in Neurological, Cardiovascular, and Inflammatory Diseases

The identification of the human cannabinoid receptors and their roles in health and disease, has been one of the most significant biochemical and pharmacological advancements to have occurred in the past few decades. In spite of the major strides made in furthering endocannabinoid research, therapeutic exploitation of the endocannabinoid system has often been a challenging task. An impaired endocannabinoid tone often manifests as changes in expression and/or functions of type 1 and/or type 2 cannabinoid receptors. It becomes important to understand how alterations in cannabinoid receptor cellular signaling can lead to disruptions in major physiological and biological functions, as they are often associated with the pathogenesis of several neurological, cardiovascular, metabolic, and inflammatory diseases. This review focusses mostly on the pathophysiological roles of type 1 and type 2 cannabinoid receptors, and it attempts to integrate both cellular and physiological functions of the cannabinoid receptors. Apart from an updated review of pre-clinical and clinical studies, the adequacy/inadequacy of cannabinoid-based therapeutics in various pathological conditions is also highlighted. Finally, alternative strategies to modulate endocannabinoid tone, and future directions are also emphasized.

Endocannabinoid System Components: Overview and Tissue Distribution

Marijuana/cannabinoid research has been transformed into mainstream science during the last half-century. Evidence based research and remarkable biotechnological advances demonstrate that phytocannabinoids and endocannabinoid (eCBs) acting on cannabinoid receptors (CBRs) regulate various aspects of human physiological, behavioral, immunological and metabolic functions. The distribution and function of the components of the endocannabinoid system (ECS) in the central nervous system (CNS) and immune processes have garnished significant research focus with major milestones. With these advances in biotechnology, rapid extension of the ECS research in the periphery has gained momentum. In this chapter, we review the components and tissue distribution of this previously unknown but ubiquitous and complex ECS that is involved in almost all aspects of mammalian physiology and pathology.

The effect of cannabinoids on the stretch reflex in multiple sclerosis spasticity

The aim of this observational study was to assess the efficacy of a tetrahydrocannabinol-cannabidiol (THC : CBD) oromucosal spray on spasticity using the stretch reflex in patients with multiple sclerosis (MS). Numeric rating scale (NRS) for spasticity, modified Ashworth scale (MAS), and the stretch reflex were assessed before and during treatment in 57 MS patients with spasticity eligible for THC : CBD treatment. A significant reduction in stretch reflex amplitude as well as significant reductions of NRS and MAS scores were observed. There was a low concordance between the three measures (stretch reflex, NRS, and MAS), likely related to the different aspects of muscle hypertonia assessed. Stretch reflex responders were taking a significantly higher number of puffs, whereas no differences were found in the responders by the other scales, suggesting that a higher dosage would add benefit if tolerated. The present study confirms the efficacy of cannabinoids in reducing spasticity in patients with MS, suggesting a higher sensitivity and specificity of the stretch reflex compared with other measures. As an objective and quantitative measure of spasticity, the stretch reflex is particularly useful to assess the effects of cannabinoids on spinal excitability and may play a role in future pharmacological studies.

Review article: the endocannabinoid system in liver disease, a potential therapeutic target

BACKGROUND

Endocannabinoids are a family of potent lipid-soluble molecules, acting on the cannabinoid (CB) receptors that mediate the effects of marijuana. The CB receptors, endocannabinoids and the enzymes involved in their synthesis and degradation are located in the brain and peripheral tissues, including the liver.

AIMS

To review the current understanding of the role of the endocannabinoid system in liver disease-associated pathophysiological conditions, and drugs targeting the endocannabinoid system as therapy for liver disease.

METHODS

Original articles and reviews were used to summarise the relevant pre-clinical and clinical research findings relating to this topic.

RESULTS

The endocannabinoid system as a whole plays an important role in liver diseases (i.e. non-alcoholic liver disease, alcoholic liver disease, hepatic encephalopathy and autoimmune hepatitis) and related pathophysiological conditions (i.e. altered hepatic haemodynamics, cirrhotic cardiomyopathy, metabolic syndrome and ischaemia/reperfusion disease). Pharmacological targeting of the endocannabinoid system has had success as treatment for patients with liver disease, but adverse events led to withdrawal of marketing approval. However, there is optimism over novel therapeutics targeting the endocannabinoid system currently in the pre-clinical stage of development.

CONCLUSIONS

The endocannabinoid system plays an important role in the pathophysiology of liver disease and its associated conditions. While some drugs targeting the endocannabinoid system have deleterious neurological adverse events, there is promise for a newer generation of therapies that do not cross the blood-brain barrier.

CNS effects of CB2 cannabinoid receptors: beyond neuro-immuno-cannabinoid activity

There are two well characterized cannabinoid receptors (CBRs), CB1-Rs and CB2-Rs, with other candidates, such as GPR55, PPARs and vanilloid TRPV1 (VR1) receptors, which are either activated by cannabinoids and/or endocannabinoids (eCBs). The neuronal and functional expression of CB2-Rs in the brain has been much less well characterized in comparison with the expression of the ubiquitous CB1-Rs. CB2-Rs were previously thought to be predominantly expressed in immune cells in the periphery and were traditionally referred to as peripheral CB2-Rs. We and others have now demonstrated the expression of CB2-Rs in neuronal, glial and endothelial cells in the brain, and this warrants a re-evaluation of the CNS effects of CB2-Rs. In the present review we summarize our current understanding of CNR2 genomic structure, its polymorphic nature, subtype specificity, from mice to human subjects, and its variants that confer vulnerabilities to neuropsychiatric disorders beyond neuro-immuno-cannabinoid activity.