Purified Cannabidiol, the main non-psychotropic component of Cannabis sativa, alone, counteracts neuronal apoptosis in experimental multiple sclerosis

S. GIACOPPO, T. SOUNDARA RAJAN, M. GALUPPO, F. POLLASTRO, G. GRASSI, P. BRAMANTI, E. MAZZON

European Review for Medical and Pharmacological Sciences, 2015, 19, 4906-4919.

Abstract. –

OBJECTIVE : Multiple Sclerosis (MS) is a global concern disease leading to a progressive, chronic and demyelinating condition, affecting the central nervous system (CNS). The pathology has an inflammatory/autoimmune origin; nevertheless, neuronal cell death mechanisms are not to be underestimated. The present study was designed to test the effects of intraperitoneal administration of cannabidiol (CBD), the main non-psychotropic cannabinoid of Cannabis sativa (CS), in an experimental model of MS. The aim is to evaluate the capability of CBD administration to thwart the cascade of mediators involved in MS-induced apoptosis.

MATERIALS AND METHODS : Experimental Autoimmune Encephalomyelitis (EAE) was induced
by immunization with myelin oligodendroglial glycoprotein (MOG)35-55 peptide in mice. After immunization, mice were observed daily for signs of EAE and weight loss. Disease signs were
evaluated using a standardized scoring system.

RESULTS : Immunohistochemical and Western blot assessments of key apoptotic markers reveal
that CBD treatment is able to avoid Fas pathway activation, phospho-ERK p42/44 and cleaved caspase-3 triggering as well as alterations in mitochondrial permeability due to Bax/Bcl-2 unbalance. Moreover, CBD interferes with p53-p21 axis activation. As results, the absence of tissue apobody formation in spinal cord tissues of EAE-mice treated with CBD was established. Most of therapeutic properties of CS are currently ascribed to the psychotropic effects of phenylterpenoid delta-9 tetrahydrocannabinol.

CONCLUSIONS : We have demonstrated that, alone, purified CBD possesses an anti-apoptotic power against the neurodegenerat ive processes underlying MS development. This represents an interesting new profile of CBD that could lead to its introduction in the clinical management of MS.

Key Words : Apoptosis, Experimental multiple sclerosis, Non-psychotropic cannabinoid, Cannabidiol, Mitochondrial permeability.

 

Introduction

Multiple sclerosis (MS) is a demyelinating disease mostly of autoimmune origin that affects and damages CNS, leading to a disabling condition1. In particular, myelin sheath loss causes a severe impairment of nerve signal transmission between the brain and spinal cord2. Actually, 2.3 million individuals are living
with MS. According to data released by National Multiple Sclerosis Society, published in 2013 and relative to the year 2009, there were about 10.400 cases/year with an incidence of 3.6 women/100.000 and 2.0 men/100.0003. Currently, pharmacological management of MS is in relationship with the course of the pathology. For the treatment of the so-classified relapsing- remitting MS (RRMS), to date disease modifying therapies (DMT) are adopted. They consist of immunomodulatory drugs, primarily belonging to IFN-β class, specifically IFN-β 1a (Avonex®, Rebif ®) and IFN-β 1b (Betaseron®, Extavia®). Recent trials are aimed at the possible introduction of teriflunomide (Aubagio®) and dimethyl fumarate (Tecfidera®) looking at their efficacy in comparison with another drug prescribed for the treatment of RRMS, the glatiramer acetate (Copaxone®)4, a synthetic analogue of myelin basic protein5. When highly active MS patients present more and more relapse episodes, the first line drug indicated is the recombinant humanized natal izumab (Tysabri®), a selective adhesion-molecule inhibitor monoclonal antibody against the integrin very late antigen-4 (VLA-4), used as monotherapy to delay progression of disability6. Sadly, the risk of contracting the John Cunningham virus (JCV) is high, especially after long treatments7. In this scenario, the new frontiers of the pharmacology look at the use of complementary and alternative medicine8,9, to counteract, if not the disease progression, at least MS symptoms that are based on the affected CNS area and that, for their plurality and variety, can require a multidisciplinary management10. Overall, symptoms can include motor control deficit (spasms and spasticity, weakness, impaired coordination, balance and functioning of the arms and legs); altered sensitivity of the limbs; neurological symptoms (vertigo, pins and needles, neuralgia and visual disturbances; neurological bladder (incontinence and constipation); as well as neuropsychological symptoms (memory loss, depression). Moreover, a sense of loss of identity is the direct consequence of physical changes and functional limitations11.

Medicinal plants are the most ancient resource of the history in the treatment of various diseases12. An example is given by Cannabis sativa (CS) r ich in terpenophenol ic constituents12. CS therapeutic use is a controversial open question which goes far beyond mere campaign on the legalization of marijuana13. In
this regard it is noteworthy to consider the recent introduction of Sativex®, a cannabinoid oromucosal spray containing a 1:1 ratio of the phenylterpenoid delta-9 tetrahydrocannabinol (THC) and cannabidiol (CBD), the two major components of CS14, for the management of symptomatic treatment of chronic pain and spasticity. Despite this combination has been approved and in the current state introduced in
several countries under this formulation, over the years the point of view of the scientific community regarding THC and CBD is changed. In particular, the dichotomy between psychotropic and non-psychotropic effects have been stressed and the most fervent supporters for the introduction of CS in clinical practice look at the beneficial phytochemicals properties that could derive by CBD isolation rather than to side possible hallucinogenic effects that may result from THC consumption. Ultimately, this is nothing more than the price that CBD, the major non-psychoactive component, pays remaining in the shadow of THC. Several experimental studies have shown that CBD possesses many properties15, often wrongly attributed by collective imagination just to THC alone and wide experimental evidences demonstrated that isolating non-psychotropic compounds by THC component provide beneficial effects for therapeutic use, mostly for CNS disorders16. Actually, all cannabinoids have a wide antioxidant and neuroprotective action17. In particular, antitumoral activity of CBD mediated by the triggering of apoptotic mechanisms is not so overly declared, but not even a mystery18. CBD exerts its effects via both the interaction with cannabinoids receptor 1 and 2 (CB1 and CB2 receptors, canonical cannabinoid receptor pathway) and activating other receptorindependent channels and by binding with various non cannabinoid receptors (such as PPARs, transient receptor potential vanilloid type 1 (TRPV1), GPR55, GPR18, GPR119 and 5-hydroxytryptamine receptor subtype 1A (5- HT1A)19.

In our study, we decided to investigate not in the wake of other authors20, the well known and assessed anti-inflammatory effect of CBD21,22, but rather its capability to avoid programmed cell death in the spinal cord of animal affected by experimental autoimmune encephalomyelitis (EAE), a model induced by Myelin Oligodendrocyte Glycoprotein (MOG)35-55 peptide injection and validated to reproduce human MS in mice23. By examining this profile of CBD, we strongly hope to provide new evidences about the efficacy of the molecule and to contribute into delineating a clearer profile of the compound so that its use should be extended to this as well as other pathologies with similar symptoms.

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