Cannabinoid control of neuroinflammation related to multiple sclerosis

Pharmacotherapeutic advances in fibromyalgia: what's new on the horizon?

INTRODUCTION

This review delves into Fibromyalgia Syndrome (FMS), a chronic pain condition demanding thorough understanding for precise diagnosis and treatment. Yet, a definitive pharmacological solution for FMS remains elusive.

AREAS COVERED

In this article, we systematically analyze various pharmacotherapeutic prospects for FMS treatment, organized into sections based on the stage of drug development and approval. We begin with an overview of FDA-approved drugs, discussing their efficacy in FMS treatment. Next, we delve into other medications currently used for FMS but still undergoing further study, including opioids and muscle relaxants. Further, we evaluate the evidence behind medications that are currently under study, such as cannabinoids and naltrexone. Lastly, we explore new drugs that are in phase II trials. Our research involved a thorough search on PUBMED, Google Scholar, and clinicaltrials.gov. We also discuss the action mechanisms of these drugs and their potential use in specific patient groups.

EXPERT OPINION

A focus on symptom-driven, combination therapy is crucial in managing FMS. There is also a need for ongoing research into drugs that target neuroinflammation, immunomodulation, and the endocannabinoid system. Bridging the gap between benchside research and clinical application is challenging, but it holds potential for more targeted and effective treatment strategies.

The Neurotherapeutic Arsenal in Cannabis sativa: Insights into Anti-Neuroinflammatory and Neuroprotective Activity and Potential Entourage Effects

Cannabis, renowned for its historical medicinal use, harbours various bioactive compounds-cannabinoids, terpenes, and flavonoids. While major cannabinoids like delta-9-tetrahydrocannabinol (THC) and cannabidiol (CBD) have received extensive scrutiny for their pharmacological properties, emerging evidence underscores the collaborative interactions among these constituents, suggesting a collective therapeutic potential. This comprehensive review explores the intricate relationships and synergies between cannabinoids, terpenes, and flavonoids in cannabis. Cannabinoids, pivotal in cannabis's bioactivity, exhibit well-documented analgesic, anti-inflammatory, and neuroprotective effects. Terpenes, aromatic compounds imbuing distinct flavours, not only contribute to cannabis's sensory profile but also modulate cannabinoid effects through diverse molecular mechanisms. Flavonoids, another cannabis component, demonstrate anti-inflammatory, antioxidant, and neuroprotective properties, particularly relevant to neuroinflammation. The entourage hypothesis posits that combined cannabinoid, terpene, and flavonoid action yields synergistic or additive effects, surpassing individual compound efficacy. Recognizing the nuanced interactions is crucial for unravelling cannabis's complete therapeutic potential. Tailoring treatments based on the holistic composition of cannabis strains allows optimization of therapeutic outcomes while minimizing potential side effects. This review underscores the imperative to delve into the intricate roles of cannabinoids, terpenes, and flavonoids, offering promising prospects for innovative therapeutic interventions and advocating continued research to unlock cannabis's full therapeutic potential within the realm of natural plant-based medicine.

Neurological Benefits, Clinical Challenges, and Neuropathologic Promise of Medical Marijuana: A Systematic Review of Cannabinoid Effects in Multiple Sclerosis and Experimental Models of Demyelination

Despite current therapeutic strategies for immunomodulation and relief of symptoms in multiple sclerosis (MS), remyelination falls short due to dynamic neuropathologic deterioration and relapses, leading to accrual of disability and associated patient dissatisfaction. The potential of cannabinoids includes add-on immunosuppressive, analgesic, neuroprotective, and remyelinative effects. This study evaluates the efficacy of medical marijuana in MS and its experimental animal models. A systematic review was conducted by a literature search through PubMed, ProQuest, and EBSCO electronic databases for studies reported since 2007 on the use of cannabidiol (CBD) and delta-9-tetrahydrocannabinol (THC) in MS and in experimental autoimmune encephalomyelitis (EAE), Theiler's murine encephalomyelitis virus-induced demyelinating disease (TMEV-IDD), and toxin-induced demyelination models. Study selection and data extraction were performed by 3 reviewers, and 28 studies were selected for inclusion. The certainty of evidence was appraised using the Cochrane GRADE approach. In clinical studies, there was low- and moderate-quality evidence that treatment with ~1:1 CBD/THC mixtures as a nabiximols (Sativex®) oromucosal spray reduced numerical rating scale (NRS) scores for spasticity, pain, and sleep disturbance, diminished bladder overactivity, and decreased proinflammatory cytokine and transcription factor expression levels. Preclinical studies demonstrated decreases in disease severity, hindlimb stiffness, motor function, neuroinflammation, and demyelination. Other experimental systems showed the capacity of cannabinoids to promote remyelination in vitro and by electron microscopy. Modest short-term benefits were realized in MS responders to adjunctive therapy with CBD/THC mixtures. Future studies are recommended to investigate the cellular and molecular mechanisms of cannabinoid effects on MS lesions and to evaluate whether medical marijuana can accelerate remyelination and retard the accrual of disability over the long term.

Association Between Hormonal Birth Control, Substance Use, and Depression

OBJECTIVE

The current study examined the impact of the use of hormonal birth control, cannabis (CB), and alcohol on depression symptoms.

STUDY DESIGN

Survey data from 3,320 college-aged women collected over a 2-year period. Depression symptoms were assessed using the PHQ-9.

RESULTS

Individuals taking hormonal birth control (N = 998; age = 19.1 ± 1.6 years) had lower overall depression scores than did those not taking birth control (N = 2,322; age = 19.1 ± 1.8 years) with 15.2% of those not taking hormonal birth control had depressive symptoms while 12.1% of those in the birth control group had depressive symptoms. Additionally, those taking hormonal birth control had higher scores on the alcohol and CB use assessment. A between-subjects ANOVA with depression score as the dependent variable found significant effects hormonal birth control use, CB and alcohol use, as well as a significant interaction between CB use and hormonal birth control use.

CONCLUSIONS

While there are some limitations (e.g., the between subjects design makes it such that there may be uncontrolled differences between groups), the results suggest that hormonal birth control use may help to reduce depressive symptoms.

IMPLICATIONS

More studies examining the impact of hormonal birth control and substance use on depression are required. The results suggest a potential interaction between CB and hormonal birth control use on depression symptoms that is not observed for alcohol. This implies that alcohol and CB may be linked to depression via different mechanisms.

Multiple sclerosis and its impact on dental care

Multiple sclerosis affects approximately 130,000 people in the UK. Due to the wide variation in the symptoms associated with this condition and their variable severity, the provision of dental care for affected patients must be determined by an individual's specific needs. This will often vary significantly over time. This paper reviews the aetiology, presentation and current management of multiple sclerosis, and explores the impact of these on oral health and the provision of dental care.

Cannabis and Autoimmunity: Possible Mechanisms of Action

Medical cannabis (MC) describes the usually inhaled or ingested use of a cannabis plant or cannabis extract for medicinal purposes. The action of whole cannabis plants is extremely complex because their large number of active compounds not only bind to a plethora of different receptors but also interact with each other both synergistically and otherwise. Renewed interest in the medicinal properties of cannabis has led to increasing research into the practical uses of cannabis derivatives, and it has been found that the endocannabinoid system (particularly CB2 receptor activation) is a possible target for the treatment of inflammatory and the autoimmune diseases related to immune cell activation. However, in vivo findings still lack, creating difficulties in applying translational cannabinoid research to human immune functions. In this review, we summarized the main mechanisms of action of medical cannabis plant especially regarding the immune system and the endocannabinoid system, looking at preliminary clinical data in three most important autoimmune diseases of three different specialities: rheumatoid arthritis, multiple sclerosis and inflammatory bowel disease.

Endocannabinoids in immune regulation and immunopathologies

Endocannabinoids are key bioactive components of the endocannabinoid system, and the profound influence of endocannabinoids on the modulation of the immune system is being increasingly appreciated. The knowledge of endocannabinoid-immune cell crosstalk will pave the way to therapeutic implications of modulators of this pathway in autoimmune and chronic inflammatory disorders. Endocannabinoids seem to exert both anti-inflammatory and pro-inflammatory effects in specific contexts, based on specific receptor engagement and the downstream signalling pathways involved. In this review, we summarized the biosynthesis, signalling and degradation of two well-studied endocannabinoids-anandamide and 2-arachidonylglycerol in immune cells. Then, we discussed the effects of these two endocannabinoids on the functioning of major innate and adaptive immune cells, along with the choice of receptors employed in such interactions. Finally, we outline our current knowledge on the involvement of anandamide and 2-arachidonylglycerol in context of inflammation, allergies, autoimmunity and metabolic disorders.

The Effect of Cannabis on the Clinical and Cytokine Profiles in Patients with Multiple Sclerosis

Background

Multiple studies have reported that cannabis administration in multiple sclerosis patients is associated with decreased symptom severity. This study was conducted to evaluate the prevalence of cannabis abuse in multiple sclerosis cases and to evaluate the effect of cannabis on serum cytokines in such cases. Patients and Methods. A total of 150 multiple sclerosis cases along with 150 healthy controls were included during the study period. All cases were subjected to history taking, neurological examination, and routine investigations. Cases were asked about cannabis intake which was confirmed by a urine test. Serum cytokines including IL-1, IL-2, IL-4, IL-10, IL-12, IL-17, IL-22, IFN-γ, IFN-β1, and TNF-α were ordered for all cases and controls.

Results

Twenty-eight cases were cannabis abusers (MS/cannabis group, 18.67%). The remaining 122 cases represented the MS group. There was no significant difference between the three groups regarding age, disease duration, or MS type. Male gender was more predominant in the MS/cannabis group, and the number of relapses was significantly lower in the same group. Fifteen cases (53.6%) reported that their symptoms were improved by cannabis. Proinflammatory cytokines were significantly elevated in the MS group compared to the MS/cannabis and control groups. Additionally, anti-inflammatory cytokines had significantly lower values in the MS group compared to the MS/cannabis and control groups. Most clinical symptoms were significantly improved in the MS/cannabis group compared to the MS group apart from sexual dysfunction, bladder symptoms, and visual disturbances. Mild side effects of cannabis were also reported.

Conclusion

Cannabis may have a positive impact on the cytokine and clinical profiles in cases with multiple sclerosis.

The Broad Concept of "Spasticity-Plus Syndrome" in Multiple Sclerosis: A Possible New Concept in the Management of Multiple Sclerosis Symptoms

Multiple sclerosis (MS) pathology progressively affects multiple central nervous system (CNS) areas. Due to this fact, MS produces a wide array of symptoms. Symptomatic therapy of one MS symptom can cause or worsen other unwanted symptoms (anticholinergics used for bladder dysfunction produce impairment of cognition, many MS drugs produce erectile dysfunction, etc.). Appropriate symptomatic therapy is an unmet need. Several important functions/symptoms (muscle tone, sleep, bladder, pain) are mediated, in great part, in the brainstem. Cannabinoid receptors are distributed throughout the CNS irregularly: There is an accumulation of CB1 and CB2 receptors in the brainstem. Nabiximols (a combination of THC and CBD oromucosal spray) interact with both CB1 and CB2 receptors. In several clinical trials with Nabiximols for MS spasticity, the investigators report improvement not only in spasticity itself, but also in several functions/symptoms mentioned before (spasms, cramps, pain, gait, sleep, bladder function, fatigue, and possibly tremor). We can conceptualize and, therefore, hypothesize, through this indirect information, that it could be considered the existence of a broad "Spasticity-Plus Syndrome" that involves, a cluster of symptoms apart from spasticity itself, the rest of the mentioned functions/symptoms, probably because they are interlinked after the increase of muscle tone and mediated, at least in part, in the same or close areas of the brainstem. If this holds true, there exists the possibility to treat several spasticity-related symptoms induced by MS pathology with a single therapy, which would permit to avoid the unnecessary adverse effects produced by polytherapy. This would result in an important advance in the symptomatic management of MS.

In Vivo Imaging of Translocator Protein in Long-term Cannabis Users

IMPORTANCE

Cannabis is the most commonly used illicit drug in the world. Cannabinoids have been shown to modulate immune responses; however, the association of cannabis with neuroimmune function has never been investigated in vivo in the human brain.

OBJECTIVE

To investigate neuroimmune activation or 18-kDa translocator protein (TSPO) levels in long-term cannabis users, and to evaluate the association of brain TSPO levels with behavioral measures and inflammatory blood biomarkers.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study based in Toronto, Ontario, recruited individuals from January 1, 2015, to October 30, 2018. Participants included long-term cannabis users (n = 24) and non-cannabis-using controls (n = 27). Cannabis users were included if they had a positive urine drug screen for only cannabis and if they used cannabis at least 4 times per week for the past 12 months and/or met the criteria for cannabis use disorder. All participants underwent a positron emission tomography scan with [18F]FEPPA, or fluorine F 18-labeled N-(2-(2-fluoroethoxy)benzyl)-N-(4-phenoxypyridin-3-yl)acetamide.

MAIN OUTCOMES AND MEASURES

Total distribution volume was quantified across regions of interest. Stress and anxiety as well as peripheral measures of inflammatory cytokines and C-reactive protein levels were also measured.

RESULTS

In total, 24 long-term cannabis users (mean [SD] age, 23.1 [3.8] years; 15 men [63%]) and 27 non-cannabis-using controls (mean [SD] age, 23.6 [4.2] years; 18 women [67%]) were included and completed all study procedures. Compared with the controls, cannabis users had higher [18F]FEPPA total distribution volume (main group effect: F1,48 = 6.5 [P = .01]; ROI effect: F1,200 = 28.4 [P < .001]; Cohen d = 0.6; 23.3% higher), with a more prominent implication for the cannabis use disorder subgroup (n = 15; main group effect: F1,39 = 8.5 [P = .006]; ROI effect: F1,164 = 19.3 [P < .001]; Cohen d = 0.8; 31.5% higher). Greater TSPO levels in the brain were associated with stress and anxiety and with higher circulating C-reactive protein levels in cannabis users.

CONCLUSIONS AND RELEVANCE

The results of this study suggest that TSPO levels in cannabis users, particularly in those with cannabis use disorder, are higher than those in non-cannabis-using controls. The findings emphasize the need for more complementary preclinical systems for a better understanding of the role of cannabinoids and TSPO in neuroimmune signaling.

Cannabinoids for the treatment of spasticity

This review summarizes studies that examined the effectiveness of cannabinoids in treating spasticity, with a focus on understanding the relevance of the existing evidence to paediatric populations. MEDLINE, Embase, PsycINFO, and the Cochrane Library were searched to identify studies that examined the use of cannabinoids in spasticity. We identified 32 studies in adult and paediatric populations. Results were summarized by condition, with adult and paediatric studies considered separately. There is evidence from randomized controlled clinical trials that cannabinoids are more effective than placebo in reducing symptoms of spasticity in adults with multiple sclerosis. Most positive effects were based on patient-rated rather than clinician-rated measures, were modest in size, and should be considered in the context of the narrow therapeutic index of cannabinoids for spasticity and adverse effects. There were comparatively few, and no large studies, of spasticity in conditions other than multiple sclerosis. Few studies have been conducted in paediatric populations. Paediatric studies of spasticity provide low quality evidence and are inadequate to inform clinical practice. Cannabinoids have modest efficacy in reducing muscle spasticity in adults with multiple sclerosis. There is limited evidence of efficacy for cannabinoid use in other conditions, particularly in paediatric populations. Studies in paediatric populations have been of low quality and are insufficient to inform clinical practice.

Interaction of neurotransmitters and neurochemicals with lymphocytes

Neurotransmitters and neurochemicals can act on lymphocytes by binding to receptors expressed by lymphocytes. This review describes lymphocyte expression of receptors for a selection of neurotransmitters and neurochemicals, the anatomical locations where lymphocytes can interact with neurotransmitters, and the effects of the neurotransmitters on lymphocyte function. Implications for health and disease are also discussed.

Cannabis and Its Secondary Metabolites: Their Use as Therapeutic Drugs, Toxicological Aspects, and Analytical Determination

Although the medicinal properties of Cannabis species have been known for centuries, the interest on its main active secondary metabolites as therapeutic alternatives for several pathologies has grown in recent years. This potential use has been a revolution worldwide concerning public health, production, use and sale of cannabis, and has led inclusively to legislation changes in some countries. The scientific advances and concerns of the scientific community have allowed a better understanding of cannabis derivatives as pharmacological options in several conditions, such as appetite stimulation, pain treatment, skin pathologies, anticonvulsant therapy, neurodegenerative diseases, and infectious diseases. However, there is some controversy regarding the legal and ethical implications of their use and routes of administration, also concerning the adverse health consequences and deaths attributed to marijuana consumption, and these represent some of the complexities associated with the use of these compounds as therapeutic drugs. This review comprehends the main secondary metabolites of Cannabis, approaching their therapeutic potential and applications, as well as their potential risks, in order to differentiate the consumption as recreational drugs. There will be also a focus on the analytical methodologies for their analysis, in order to aid health professionals and toxicologists in cases where these compounds are present.

Cannabinoid exposure during pregnancy and its impact on immune function

Cannabinoids are the most commonly abused illicit drugs worldwide. While cannabis can be beneficial for certain heath conditions, abuse of potent synthetic cannabinoids has been on the rise. Exposure to cannabinoids is also prevalent in women of child-bearing age and pregnant women. These compounds can cross the placental barrier and directly affect the fetus. They mediate their effects primarily through G-protein coupled cannabinoid receptors, CB1 and CB2. In addition to significant neurological effects, cannabinoids can trigger robust immunomodulation by altering cytokine levels, causing apoptosis of lymphoid cells and inducing suppressor cells of the immune system. Profound effects of cannabinoids on the immune system as discussed in this review, suggest that maternal exposure during pregnancy could lead to dysregulation of innate and adaptive immune system of developing fetus and offspring potentially leading to weakening of immune defenses against infections and cancer later in life. Emerging evidence also indicates the underlying role of epigenetic mechanisms causing long-lasting impact following cannabinoid exposure in utero.

Target regulation of PI3K/Akt/mTOR pathway by cannabidiol in treatment of experimental multiple sclerosis

This study was aimed to investigate whether treatment with purified cannabidiol (CBD) may counteract the development of experimental multiple sclerosis (MS), by targeting the PI3K/Akt/mTOR pathway. Although the PI3K/Akt/mTOR pathway was found to be activated by cannabinoids in several immune and non-immune cells, currently, there is no data about the effects of CBD in the PI3K/Akt/mTOR activity in MS. Experimental Autoimmune Encephalomyelitis (EAE), the most common model of MS, was induced in C57BL/6 mice by immunization with myelin oligodendroglial glycoprotein peptide (MOG)_35-55. After EAE onset, which occurs approximately 14days after disease induction, mice were daily intraperitoneally treated with CBD (10mg/kg mouse) and observed for clinical signs of EAE. At 28days from EAE-induction, mice were euthanized and spinal cord tissues were sampled to perform immunohistochemical evaluations and western blot analysis. Our results showed a clear downregulation of the PI3K/Akt/mTOR pathway following EAE induction. CBD treatment was able to restore it, increasing significantly the phosphorylation of PI3K, Akt and mTOR. Also, an increased level of BNDF in CBD-treated mice seems to be involved in the activation of PI3K/Akt/mTOR pathway. In addition, our data demonstrated that therapeutic efficacy of CBD treatment is due to reduction of pro-inflammatory cytokines, like IFN-γ and IL-17 together with an up-regulation of PPARγ. Finally, CBD was found to promote neuronal survival by inhibiting JNK and p38 MAP kinases. These results provide an interesting discovery about the regulation of the PI3K/Akt/mTOR pathway by cannabidiol administration, that could be a new potential therapeutic target for MS management.

Inflammatory markers among adolescents and young adults with bipolar spectrum disorders

OBJECTIVE

Despite burgeoning literature in middle-aged adults, little is known regarding proinflammatory markers (PIMs) among adolescents and young adults with bipolar disorder. Similarly, few prior studies have considered potential confounds when examining the association between PIMs and bipolar disorder characteristics. We therefore retrospectively examined these topics in the Course and Outcome of Bipolar Youth (COBY) study.

METHOD

Subjects were 123 adolescents and young adults (mean [SD] = 20.4 ± 3.8 years; range, 13.4-28.3 years) in COBY, enrolled between October 2000 and July 2006. DSM-IV diagnoses were determined using the Schedule for Affective Disorders and Schizophrenia for School-Age Children (K-SADS). Clinical characteristics during the preceding 6 months, including mood, comorbidity, and treatment, were evaluated using the Longitudinal Interval Follow-Up Evaluation (LIFE). Serum levels of interleukin (IL)-6, tumor necrosis factor (TNF)-α, and high-sensitivity C-reactive protein (hsCRP) were assayed. Primary analyses examined the association of PIMs with bipolar disorder characteristics during the preceding 6 months.

RESULTS

Several lifetime clinical characteristics were significantly associated with PIMs in multivariable analyses, including longer illness duration (P = .005 for IL-6; P = .0004 for hsCRP), suicide attempts (P = .01 for TNF-α), family history of suicide attempts or completion (P = .01 for hsCRP), self-injurious behavior (P =.005 for TNF-α), substance use disorder (SUD) (P < .0001 for hsCRP), and family history of SUD (P = .02 for TNF-α; P = .01 for IL-6). The following bipolar disorder characteristics during the preceding 6 months remained significantly associated with PIMs in multivariable analyses that controlled for differences in comorbidity and treatment: for TNF-α, percentage of weeks with psychosis (χ(2) = 5.7, P =.02); for IL-6, percentage of weeks with subthreshold mood symptoms (χ(2)= 8.3, P = .004) and any suicide attempt (χ(2) = 6.1, P = .01); for hsCRP, maximum severity of depressive symptoms (χ(2) = 8.3, P =.004).

CONCLUSION

Proinflammatory markers may be relevant to bipolar disorder characteristics as well as other clinical characteristics among adolescents and young adults with bipolar disorder. Traction toward validating PIMs as clinically relevant biomarkers in bipolar disorder will require repeated measures of PIMs and incorporation of relevant covariates.

A new formulation of cannabidiol in cream shows therapeutic effects in a mouse model of experimental autoimmune encephalomyelitis

Background

The present study was designed to investigate the efficacy of a new formulation of alone, purified cannabidiol (CBD) (>98 %), the main non-psychotropic cannabinoid of Cannabis sativa, as a topical treatment in an experimental model of autoimmune encephalomyelitis (EAE), the most commonly used model for multiple sclerosis (MS). Particularly, we evaluated whether administration of a topical 1 % CBD-cream, given at the time of symptomatic disease onset, could affect the EAE progression and if this treatment could also recover paralysis of hind limbs, qualifying topical-CBD for the symptomatic treatment of MS.

Methods

In order to have a preparation of 1 % of CBD-cream, pure CBD have been solubilized in propylene glycoland basic dense cream O/A. EAE was induced by immunization with myelin oligodendroglial glycoprotein peptide (MOG35–55) in C57BL/6 mice. After EAE onset, mice were allocated into several experimental groups (Naïve, EAE, EAE-1 % CBD-cream, EAE-vehicle cream, CTRL-1 % CBD-cream, CTRL-vehicle cream). Mice were observed daily for signs of EAE and weight loss. At the sacrifice of the animals, which occurred at the 28^th day from EAE-induction, spinal cord and spleen tissues were collected in order to perform histological evaluation, immunohistochemistry and western blotting analysis.

Results

Achieved results surprisingly show that daily treatment with topical 1 % CBD-cream may exert neuroprotective effects against EAE, diminishing clinical disease score (mean of 5.0 in EAE mice vs 1.5 in EAE + CBD-cream), by recovering of paralysis of hind limbs and by ameliorating histological score typical of disease (lymphocytic infiltration and demyelination) in spinal cord tissues. Also, 1 % CBD-cream is able to counteract the EAE-induced damage reducing release of CD4 and CD8α T cells (spleen tissue localization was quantified about 10,69 % and 35,96 % of positive staining respectively in EAE mice) and expression of the main pro-inflammatory cytokines as well as several other direct or indirect markers of inflammation (p-selectin, IL-10, GFAP, Foxp3, TGF-β, IFN-γ), oxidative injury (Nitrotyrosine, iNOS, PARP) and apoptosis (Cleaved caspase 3).

Conclusion

All these data suggest an interesting new profile of CBD that could lead to its introduction in the clinical management of MS and its associated symptoms at least in association with current conventional therapy.

Electronic supplementary material

The online version of this article (doi:10.1186/s40199-015-0131-8) contains supplementary material, which is available to authorized users.

Distinct modulation of the endocannabinoid system upon kainic acid-induced in vivo seizures and in vitro epileptiform bursting

There is clear evidence on the neuroprotective role of the endocannabinoid (eCB) signaling cascade in various models of epilepsy. In particular, increased levels of eCBs protect against kainic acid (KA)-induced seizures. However, the molecular mechanisms underlying this effect and its age-dependence are still unknown. To clarify this issue, we investigated which step of the biosynthetic and catabolic pathways of the eCBs may be responsible for the eCB-mediated neuroprotection in the hippocampus of P14 and P56-70 KA-treated rats. We found that both anandamide and N-palmitoylethanolamine, together with their biosynthetic enzyme significantly increased in the hippocampus of younger KA-treated rats, while decreasing in adults. In contrast, the levels of the other major eCB, 2-arachidonoylglycerol, similar to its biosynthetic enzyme, were higher in the hippocampus of P56-70 compared to P14 rats. In line with these data, extracellular field recordings in CA1 hippocampus showed that enhancement of endogenous AEA and 2-AG significantly counteracted KA-induced epileptiform bursting in P56-70 and P14 rats, respectively. On the contrary, while the CB1R antagonist SR141716 per se did not affect the population spike, it did worsen KA-induced bursts, confirming increased eCB tone upon KA treatment. Altogether these data indicate an age-specific alteration of the eCB system caused by KA and provide insights for the protective mechanism of the cannabinoid system against epileptiform discharges.

Developmental effects of cannabinoids on zebrafish larvae

Cannabinoids are natural or synthetic compounds related chemically to (-)-(6aR,10aR)-6,6,9-trimethyl-3-pentyl-6a,7,8,10a-tetrahydro-6H-benzo[c]chromen-1-ol (Δ(9)-THC), the principle psychotropic constituent of the hemp plant, Cannabis sativa L. Here we examine the effects of the cannabinoids Δ(9)-THC, (R)-(+)-[2,3-dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo [1,2,3-de]-1,4-benzoxazin-6-yl]-1-napthalenylmethanone and 2-[(1R,2R,5R)-5-hydroxy-2-(3-hydroxypropyl) cyclohexyl]-5-(2-methyloctan-2-yl)phenol, and the cannabinoid antagonist (AM 251). Exposures were either acute (1-12-h exposure at 108 hours of postfertilization [hpf]) or chronic (96-h exposure starting at 24 hpf). Geometric range finding was used to determine the experimental concentrations. The concentration of the chemical that kills 50% of the test animals in a given time (LC50) was determined based on cumulative mortality at 5 days of postfertilization. At day 5, behavioral analysis (visual motor response test) was carried out in which movement of individual larvae was analysed using automated video-tracking. With acute exposure, embryos showed a biphasic response to the dark challenge with all three cannabinoids tested. This response consisted of stimulation of the locomotor activity at low concentrations, suppression at high doses. With chronic exposure, embryos habituated to the effects of all three cannabinoids when assayed with the dark challenge phase. Further, the excitation was ameliorated when the antagonist AM 251 was coadministered with the cannabinoid. When AM 251 was administered on its own (chronically or acutely), the locomotor activity was suppressed at high concentrations. We examined the embryos for a range of malformations after chronic exposure to cannabinoid. Only Δ(9)-THC was associated with a significant increase in malformations at 5d (yolk sac and pericardial edema, bent tail/body axis). We conclude that cannabinoids have behavioral effects in zebrafish that are comparable to some of those reported in the literature for mammals. In particular, the acute exposure response resembles behavioral effects reported for adult rodents. Our data are consistent with these behavioral effects being mediated, at least in part, by the CB1 receptor.

Laquinimod prevents inflammation-induced synaptic alterations occurring in experimental autoimmune encephalomyelitis

BACKGROUND

There are two generally accepted strategies for treating multiple sclerosis (MS), preventing central nervous system (CNS) damage indirectly through immunomodulatory interventions and/or repairing CNS damage by promoting remyelination. Both approaches also provide neuroprotection since they can prevent, indirectly or directly, axonal damage.

OBJECTIVE

Recent experimental and clinical evidence indicates that the novel immunomodulatory drug laquinimod can exert a neuroprotective role in MS. Whether laquinimod-mediated neuroprotection is exerted directly on neuronal cells or indirectly via peripheral immunomodulation is still unclear.

METHODS

C57Bl/6 experimental autoimmune encephalomyelitis (EAE) mice, immunised with myelin oligodendrocyte glycoprotein (MOG)35-55 peptide, were treated for 26 days with subcutaneous daily injections of laquinimod (from 1 to 25 mg/kg). Patch clamp electrophysiology was performed on acute brain striatal slices from EAE mice treated with daily (25 mg/kg) laquinimod and on acute brain striatal slices from control mice bathed with laquinimod (1-30 µM).

RESULTS

Both preventive and therapeutic laquinimod treatment fully prevented the alterations of GABAergic synapses induced by EAE, the first limiting also glutamatergic synaptic alterations. This dual effect might, in turn, have limited glutamatergic excitotoxicity, a phenomenon previously observed early during EAE and possibly correlated with later axonal damage. Furthermore, laquinimod treatment also preserved cannabinoid CB1 receptor sensitivity, normally lost during EAE. Finally, laquinimod per se was able to regulate synaptic transmission by increasing inhibitory post-synaptic currents and, at the same time, reducing excitatory post-synaptic currents.

CONCLUSIONS

Our data suggest a novel neuroprotective mechanism by which laquinimod might in vivo protect from neuronal damage occurring as a consequence of inflammatory immune-mediated demyelination.

Signaling through cannabinoid receptor 2 suppresses murine dendritic cell migration by inhibiting matrix metalloproteinase 9 expression

Administration of cannabinoid receptor 2 (CB2R) agonists in inflammatory and autoimmune disease and CNS injury models results in significant attenuation of clinical disease, and reduction of inflammatory mediators. Previous studies reported that CB2R signaling also reduces leukocyte migration. Migration of dendritic cells (DCs) to various sites is required for their activation and for the initiation of adaptive immune responses. Here, we report for the first time that CB2R signaling affects DC migration in vitro and in vivo, primarily through the inhibition of matrix metalloproteinase 9 (MMP-9) expression. Reduced MMP-9 production by DCs results in decreased migration to draining lymph nodes in vivo and in vitro in the matrigel migration assay. The effect on Mmp-9 expression is mediated through CB2R, resulting in reduction in cAMP levels, subsequent decrease in ERK activation, and reduced binding of c-Fos and c-Jun to Mmp-9 promoter activator protein 1 sites. We postulate that, by dampening production of MMP-9 and subsequent MMP-9-dependent DC migration, cannabinoids contribute to resolve acute inflammation and to reestablish homeostasis. Selective CB2R agonists might be valuable future therapeutic agents for the treatment of chronic inflammatory conditions by targeting activated immune cells, including DCs.

Evaluation of the Effects of Sativex (THC BDS: CBD BDS) on Inhibition of Spasticity in a Chronic Relapsing Experimental Allergic Autoimmune Encephalomyelitis: A Model of Multiple Sclerosis

This study investigated the antispasticity potential of Sativex in mice. Chronic relapsing experimental allergic encephalomyelitis was induced in adult ABH mice resulting in hind limb spasticity development. Vehicle, Sativex, and baclofen (as a positive control) were injected intravenously and the “stiffness” of limbs assessed by the resistance force against hind limb flexion. Vehicle alone caused no significant change in spasticity. Baclofen (5 mg/kg) induced approximately a 40% peak reduction in spasticity. Sativex dose dependently reduced spasticity; 5 mg/kg THC + 5 mg/kg CBD induced approximately a 20% peak reduction; 10 mg/kg THC + 10 mg/kg CBD produced approximately a 40% peak reduction in spasticity. Sativex has the potential to reduce spasticity in an experimental mouse model of multiple sclerosis (MS). Baclofen reduced spasticity and served as a positive control. Sativex (10 mg/kg) was just as effective as baclofen, providing supportive evidence for Sativex use in the treatment of spasticity in MS.

The fatty acid amide hydrolase inhibitor URB597 exerts anti-inflammatory effects in hippocampus of aged rats and restores an age-related deficit in long-term potentiation

BACKGROUND

Several factors contribute to the deterioration in synaptic plasticity which accompanies age and one of these is neuroinflammation. This is characterized by increased microglial activation associated with increased production of proinflammatory cytokines like interleukin-1β (IL-1β). In aged rats these neuroinflammatory changes are associated with a decreased ability of animals to sustain long-term potentiation (LTP) in the dentate gyrus. Importantly, treatment of aged rats with agents which possess anti-inflammatory properties to decrease microglial activation, improves LTP. It is known that endocannabinoids, such as anandamide (AEA), have anti-inflammatory properties and therefore have the potential to decrease the age-related microglial activation. However, endocannabinoids are extremely labile and are hydrolyzed quickly after production. Here we investigated the possibility that inhibiting the degradation of endocannabinoids with the fatty acid amide hydrolase (FAAH) inhibitor, URB597, could ameliorate age-related increases in microglial activation and the associated decrease in LTP.

METHODS

Young and aged rats received subcutaneous injections of the FAAH inhibitor URB597 every second day and controls which received subcutaneous injections of 30% DMSO-saline every second day for 28 days. Long-term potentiation was recorded on day 28 and the animals were sacrificed. Brain tissue was analyzed for markers of microglial activation by PCR and for levels of endocannabinoids by liquid chromatography coupled to tandem mass spectrometry.

RESULTS

The data indicate that expression of markers of microglial activation, MHCII, and CD68 mRNA, were increased in the hippocampus of aged, compared with young, rats and that these changes were associated with increased expression of the proinflammatory cytokines interleukin (IL)-1β and tumor necrosis factor-α (TNFα) which were attenuated by treatment with URB597. Coupled with these changes, we observed an age-related decrease in LTP in the dentate gyrus which was partially restored in URB597-treated aged rats. The data suggest that enhancement of levels of endocannabinoids in the brain by URB597 has beneficial effects on synaptic function, perhaps by modulating microglial activation.

The endocannabinoid system: a revolving plate in neuro-immune interaction in health and disease

Studies of the last 40 years have brought to light an important physiological network, the endocannabinoid system. Endogenous and exogenous cannabinoids mediate their effects through activation of specific cannabinoid receptors. This modulatory homoeostatic system operates in the regulation of brain function and also in the periphery. The cannabinoid system has been shown to be involved in regulating the immune system. Studies examining the effect of cannabinoid-based drugs on immunity have shown that many cellular and cytokine mechanisms are modulated by these agents, thus raising the hypothesis that these compounds may be of value in the management of chronic inflammatory diseases. The special properties of endocannabinoids as neurotransmitters, their pleiotropic effects and the impact on immune function show that the endocannabinoid system represents a revolving plate of neural and immune interactions. In this paper, we outline current information on immune effects of cannabinoids in health and disease.

5, 8, 11, 14-eicosatetraynoic acid suppresses CCL2/MCP-1 expression in IFN-γ-stimulated astrocytes by increasing MAPK phosphatase-1 mRNA stability

Background

The peroxisome proliferator-activated receptor (PPAR)-α activator, 5,8,11,14-eicosatetraynoic acid (ETYA), is an arachidonic acid analog. It is reported to inhibit up-regulation of pro-inflammatory genes; however, its underlying mechanism of action is largely unknown. In the present study, we focused on the inhibitory action of ETYA on the expression of the chemokine, CCL2/MCP-1, which plays a key role in the initiation and progression of inflammation.

Methods

To determine the effect of ETYA, primary cultured rat astrocytes and microglia were stimulated with IFN-γ in the presence of ETYA and then, expression of CCL2/MCP-1 and MAPK phosphatase (MKP-1) were determined using RT-PCR and ELISA. MKP-1 mRNA stability was evaluated by treating actinomycin D. The effect of MKP-1 and human antigen R (HuR) was analyzed by using specific siRNA transfection system. The localization of HuR was analyzed by immunocytochemistry and subcellular fractionation experiment.

Results

We found that ETYA suppressed CCL2/MCP-1 transcription and secretion of CCL2/MCP-1 protein through up-regulation of MKP-1mRNA levels, resulting in suppression of c-Jun N-terminal kinase (JNK) phosphorylation and activator protein 1 (AP1) activity in IFN-γ-stimulated brain glial cells. Moreover, these effects of ETYA were independent of PPAR-α. Experiments using actinomycin D revealed that the ETYA-induced increase in MKP-1 mRNA levels reflected an increase in transcript stability. Knockdown experiments using small interfering RNA demonstrated that this increase in MKP-1 mRNA stability depended on HuR, an RNA-binding protein known to promote enhanced mRNA stability. Furthermore, ETYA-induced, HuR-mediated mRNA stabilization resulted from HuR-MKP-1 nucleocytoplasmic translocation, which served to protect MKP-1 mRNA from the mRNA degradation machinery.

Conclusion

ETYA induces MKP-1 through HuR at the post-transcriptional level in a receptor-independent manner. The mechanism revealed here suggests eicosanoids as potential therapeutic modulators of inflammation that act through a novel target.

Cannabinoids ameliorate disease progression in a model of multiple sclerosis in mice, acting preferentially through CB1 receptor-mediated anti-inflammatory effects

Multiple sclerosis (MS) is an autoimmune disease that affects the CNS and it is characterized by inflammation, demyelination, remyelination, gliosis and axonal damage that occur mainly in the spinal cord. Cannabinoids have been proposed as promising therapeutic agents in MS given their capability to alleviate specific MS symptoms (e.g., spasticity, pain). Although MS has been considered mainly an inflammatory disorder, recent evidence, however, revealed the importance of neurodegenerative events, opening the possibility that cannabinoid agonists, given their cytoprotective properties, may also serve to reduce oligodendrocyte death and axonal damage in MS. Thus, the treatment with WIN55,512-2, a potent CB(1) and CB(2) agonist, was reported to be effective to ameliorate tremor and spasticity in mice with chronic relapsing experimental autoimmune encephalomyelitis, a murine model of MS, but also to delay disease progression in this and other murine models of MS. The purpose of this investigation was to further explore the mechanism(s) underlying the amelioration in disease progression caused by WIN55,212-2. We have particularly focused on anti-glutamatergic and anti-inflammatory effects of this cannabinoid agonist. In this study, we used mice treated with myelin oligodendrocyte glycoprotein (MOG) that induces a progressive pattern of EAE and conducted the pharmacological experiments in early stages of the disease. As expected, the administration of WIN55,512-2 (5 mg/kg, i.p) had a positive effect in reducing neurological disability and improving motor coordination of EAE mice. Levels of glutamate and GABA in the spinal cord and also in the brainstem of EAE mice were similar to control animals, and, accordingly, they were not altered by the treatment with WIN55,212-2. However, EAE mice showed some subtle alterations in mRNA levels for the glutamate transporter GLT1 and, to a lesser extent, GLAST too, changes that were altered by the treatment with WIN55,212-2 in the spinal cord, but not in the brainstem. Regarding to inflammatory responses, EAE mice showed a marked up-regulation in mRNA levels for COX-2, inducible NOS and TNF-α in the spinal cord and the brainstem, these responses being attenuated after the treatment with WIN55,212-2. We also observed the presence of cell aggregates in the spinal cord of EAE mice that were significantly attenuated by the treatment with WIN55,212-2. Immunohistochemical analysis (with Iba-1 and Cd11b) of these aggregates indicated that they corresponded to microglia (resident macrophages) and peripheral macrophages. Lastly, experiments conducted with selective antagonists for the CB(1) (e.g. rimonabant) or CB(2) (e.g. AM-630) receptors revealed that WIN55,212-2 effects in EAE mice were mediated by the activation of CB(1) but not CB(2) receptors, as reflected the reversion of positive effects of this cannabinoid on neurological decline, TNF-α generation and accumulation of cell aggregates in the spinal cord with rimonabant, but not with AM-630. This was concordant with the lack of positive effects on neurological decline observed in EAE mice when they received HU-308, a selective CB(2) receptor agonist, instead WIN55,212-2. In summary, the treatment of EAE mice with the cannabinoid agonist WIN55,512-2 reduced their neurological disability and the progression of the disease. This effect was exerted through the activation of CB(1) receptors, which would exert a positive influence in the reduction of inflammatory events linked to the pathogenesis of this disease.

Reduced infarct size and accumulation of microglia in rats treated with WIN 55,212-2 after neonatal stroke

Cannabinoids have emerged as brain protective agents under neurodegenerative conditions. Many neuroprotective actions of cannabinoids depend on the activation of specific receptors, cannabinoid receptor type 1 (CB1R) and type 2 (CB2R). The aim of the present study was to determine whether the CB2R and CB1R agonist WIN 55,212-2 (WIN) protects neonatal brain against focal cerebral ischemia-reperfusion and whether anti-inflammatory mechanisms play a role in protection. Seven-day-old rats were subjected to 90-min middle cerebral artery occlusion (MCAO), and injured rats were identified by diffusion-weighted MRI during the occlusion. After reperfusion, rats were subcutaneously administered 1 mg/kg of WIN or vehicle twice daily until sacrifice. MCAO led to increased mRNA expression of CB2R (but not CB1R), chemokine receptors (CCR2 and CX3CR1), and cytokines (IL-1β and TNFα), as well as increased protein expression of chemokines MCP-1 and MIP-1α and microglial activation 24 h after MCAO. WIN administration significantly reduced microglial activation at this point and attenuated infarct volume and microglial accumulation and proliferation in the injured cortex 72 h after MCAO. Cumulatively, our results show that the cannabinoid agonist WIN protects against neonatal focal stroke in part due to inhibitory effects on microglia.

Cannabinoid receptor and N-acyl phosphatidylethanolamine phospholipase D--evidence for altered expression in multiple sclerosis

Cannabinoids have been shown to have a beneficial effect in both animal models of multiple sclerosis (MS) and human disease, although the mechanisms of action are unclear. We examined expression of the major cannabinoid receptors [(CBRs) cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2)] and a key enzyme involved in synthesis of the endocannabinoid anandamide [N-acyl phosphatidylethanolamine phospholipase D (NAPE-PLD)] in autopsy brain samples from patients with MS. CB1 was expressed in neurons, injured axons, oligodendrocytes, macrophages/microglia, some astrocytes, endothelial cells, smooth muscle cells and pericytes. CB2 and NAPE-PLD were localized to cerebral endothelial cells, pericytes, smooth muscle cells, astrocytes and macrophages/microglia. NAPE-PLD immunoreactivity was also seen in neurons. Endothelial CB2 expression was greatest in chronic inactive plaques, and in areas was seen in segments of endothelium where the endothelial expression of adhesion molecules (VCAM-1 and ICAM-1) was focally undetectable, and was often expressed in areas of blood-brain barrier damage. Vascular density was increased in chronic active plaques and normal-appearing white matter compared with controls. These data support findings from animal models which suggest a role for the endocannabinoid system in the MS, particularly in the regulation of endothelial leukocyte adhesion and the cellular response to injury.

Acute and chronic cannabinoid extracts administration affects motor function in a CREAE model of multiple sclerosis

AIM OF THE STUDY

The multiple sclerosis is an immuno-mediated disorder of the Central Nervous System characterized by inflammatory processes and neurodegenerative changes. It has been shown that the endocannabinoid system is altered in this disease and that the exogenous cannabinoids may play a possible role in its therapeutic management. The aim of the present study was to investigate the efficacy of crude extracts of Cannabis sativa on motor symptoms in the chronic relapsing experimental autoimmune encephalomyelitis (CREAE), a murine model of multiple sclerosis.

MATERIALS AND METHODS

CREAE-induced mice were injected by different crude ethanolic extracts from Cannabis sativa, containing Δ⁹-tetrahydrocannabinol, cannabidiol, or cannabinoid-free, respectively. The effect of the combined treatment with Δ⁹-tetrahydrocannabinol and cannabidiol extracts has also been investigated. All extracts were administered in acute and chronic experimental protocols.

RESULTS

The chronic administration of Δ⁹-tetrahydrocannabinol-rich extract resulted in a significant reduction of neurological deficits that lasted until the end of the observations. The acute and chronic treatments with the cannabidiol-rich extract resulted unable to induce changes of neurological signs. However, during the relapse phase a significant decrease of neurological scores was observed. The combined treatment with Δ⁹-tetrahydrocannabinol and cannabidiol extracts was ineffective, whereas the acute administration of the cannabinoid-free extract showed a significant improvement.

CONCLUSIONS

Our study shows a patchy effect of different cannabinoid extracts on CREAE-induced motor deficits. Although the effect of crude extracts of Cannabis sativa here reported need to be further investigated to define the exact therapeutic target of each cannabinoid, it may represent a possible therapeutic approach for the management of the multiple sclerosis.

Modulation of the endocannabinoid system: neuroprotection or neurotoxicity?

There is now a large volume of data indicating that compounds activating cannabinoid CB(1) receptors, either directly or indirectly by preventing the breakdown of endogenous cannabinoids, can protect against neuronal damage produced by a variety of neuronal "insults". Given that such neurodegenerative stimuli result in increased endocannabinoid levels and that animals with genetic deletions of CB(1) receptors are more susceptible to the deleterious effects of such stimuli, a case can be made for an endogenous neuroprotective role of endocannabinoids. However, this is an oversimplification of the current literature, since (a) compounds released together with the endocannabinoids can contribute to the neuroprotective effect; (b) other proteins, such as TASK-1 and PPARalpha, are involved; (c) the CB(1) receptor antagonist/inverse agonist rimonabant has also been reported to have neuroprotective properties in a number of animal models of neurodegenerative disorders. Furthermore, the CB(2) receptor located on peripheral immune cells and activated microglia are potential targets for novel therapies. In terms of the clinical usefulness of targeting the endocannabinoid system for the treatment of neurodegenerative disorders, data are emerging, but important factors to be considered are windows of opportunity (for acute situations such as trauma and ischemia) and the functionality of the target receptors (for chronic neurodegenerative disorders such as Alzheimer's disease).

Endocannabinoids and pregnancy

Acylethanolamides such as anandamide (AEA), and monoacylglycerols like 2-arachidonoylglycerol are endocannabinoids that bind to cannabinoid, vanilloid and peroxisome proliferator-activated receptors. These compounds, their various receptors, the purported membrane transporter(s), and related enzymes that synthesize and degrade them are collectively referred to as the "endocannabinoid system (ECS)". Poorly defined cellular and molecular mechanisms control the biological actions of the ECS. Over the last decade evidence has been emerging to suggest that the ECS plays a significant role in various aspects of human reproduction. In this review, we summarize our current understanding of this role especially the involvement of AEA and related ECS elements in regulating oogenesis, embryo oviductal transport, blastocyst implantation, placental development and pregnancy outcomes, and sperm survival, motility, capacitation and acrosome reaction. Additionally, the possibility that plasma and tissue AEA and other cannabinoids may represent reliable diagnostic markers of natural and assisted reproduction and pregnancy outcomes in women will be discussed.

Cannabinoids and the immune system: an overview

Cannabinoids can influence the immune network. Data on the impact of exogenous cannabinoid ligands on immune function serve not only to understand how the endocannabinoid system modulates immune phenomena associated with infection or inflammation, but also to identify therapeutic targets for immune diseases. Cannabinoids can modulate immune reactions in the periphery but also in the brain, influence T cell subset balance and cytokine expression and play a role in the balance between neuroinflammation and neurodegeneration. Immune cells can synthesize endocannabinoids and also be influenced by cannabinoid analogues. Cannabinoid receptors show different expression on immune cells depending on activation status and stimuli. The complexity of relation between cannabinoid ligands of various classes and cannabinoid receptors brought the need to refine the simple conceptual frame of agonist-antagonists and offered potential implications for understanding interactions in pathological conditions. The immune influence of cannabinoid ligands is not fully elucidated. However, aspects of their immunomodulatory effects provide the basis for a context-dependent targeted therapeutic approach, thus leading to the possibility for the use of cannabinoids in the treatment of inflammatory disease.

Cannabinoid system in the skin - a possible target for future therapies in dermatology

Cannabinoids and their derivatives are group of more than 60 biologically active chemical agents, which have been used in natural medicine for centuries. The major agent of exogenous cannabinoids is Delta(9)-tetrahydrocannabinol (Delta(9)-THC), natural psychoactive ingredient of marijuana. However, psychoactive properties of these substances limited their use as approved medicines. Recent discoveries of endogenous cannabinoids (e.g. arachidonoylethanolamide, 2-arachidonoylglycerol or palmithyloethanolamide) and their receptors initiated discussion on the role of cannabinoid system in physiological conditions as well as in various diseases. Based on the current knowledge, it could be stated that cannabinoids are important mediators in the skin, however their role have not been well elucidated yet. In our review, we summarized the current knowledge about the significant role of the cannabinoid system in the cutaneous physiology and pathology, pointing out possible future therapeutic targets.

Cannabinoids Delta(9)-tetrahydrocannabinol and cannabidiol differentially inhibit the lipopolysaccharide-activated NF-kappaB and interferon-beta/STAT proinflammatory pathways in BV-2 microglial cells

Cannabinoids have been shown to exert anti-inflammatory activities in various in vivo and in vitro experimental models as well as ameliorate various inflammatory degenerative diseases. However, the mechanisms of these effects are not completely understood. Using the BV-2 mouse microglial cell line and lipopolysaccharide (LPS) to induce an inflammatory response, we studied the signaling pathways engaged in the anti-inflammatory effects of cannabinoids as well as their influence on the expression of several genes known to be involved in inflammation. We found that the two major cannabinoids present in marijuana, Delta(9)-tetrahydrocannabinol (THC) and cannabidiol (CBD), decrease the production and release of proinflammatory cytokines, including interleukin-1beta, interleukin-6, and interferon (IFN)beta, from LPS-activated microglial cells. The cannabinoid anti-inflammatory action does not seem to involve the CB1 and CB2 cannabinoid receptors or the abn-CBD-sensitive receptors. In addition, we found that THC and CBD act through different, although partially overlapping, mechanisms. CBD, but not THC, reduces the activity of the NF-kappaB pathway, a primary pathway regulating the expression of proinflammatory genes. Moreover, CBD, but not THC, up-regulates the activation of the STAT3 transcription factor, an element of homeostatic mechanism(s) inducing anti-inflammatory events. Following CBD treatment, but less so with THC, we observed a decreased level of mRNA for the Socs3 gene, a main negative regulator of STATs and particularly of STAT3. However, both CBD and THC decreased the activation of the LPS-induced STAT1 transcription factor, a key player in IFNbeta-dependent proinflammatory processes. In summary, our observations show that CBD and THC vary in their effects on the anti-inflammatory pathways, including the NF-kappaB and IFNbeta-dependent pathways.

The endocannabinoid system and the regulation of neural development: potential implications in psychiatric disorders

During brain development, functional neurogenesis is achieved by the concerted action of various steps that include the expansion of progenitor cells, neuronal specification, and establishment of appropriate synapses. Brain patterning and regionalization is regulated by a variety of extracellular signals and morphogens that, together with neuronal activity, orchestrate and regulate progenitor proliferation, differentiation, and neuronal maturation. In the adult brain, CB(1) cannabinoid receptors are expressed at very high levels in selective areas and are engaged by endocannabinoids, which act as retrograde messengers controlling neuronal function and preventing excessive synaptic activity. In addition, the endocannabinoid system is present at early developmental stages of nervous system formation. Recent studies have provided novel information on the role of this endogenous neuromodulatory system in the control of neuronal specification and maturation. Thus, cannabinoid receptors and locally produced endocannabinoids regulate neural progenitor proliferation and pyramidal specification of projecting neurons. CB(1) receptors also control axonal navigation, migration, and positioning of interneurons and excitatory neurons. Loss of function studies by genetic ablation or pharmacological blockade of CB(1) receptors interferes with long-range subcortical projections and, likewise, prenatal cannabinoid exposure induces different functional alterations in the adult brain. Potential implications of these new findings, such as the participation of the endocannabinoid system in the pathogenesis of neurodevelopmental disorders (e.g., schizophrenia) and the regulation of neurogenesis in brain depression, are discussed herein.

Quantification of myelin and axon pathology during relapsing progressive experimental autoimmune encephalomyelitis in the Biozzi ABH mouse

Multiple sclerosis is an immune-mediated demyelinating disease, with axonal loss underlying long-term progressive disability. In this study, we have analyzed axonal and myelin pathology in a chronic relapsing-remitting experimental autoimmune encephalomyelitis model in Biozzi ABH mice induced by immunization with a syngeneic spinal cord homogenate. The animals were followed for3 months; inflammation, T-cell infiltration, demyelination, and axonal loss were examined at various time points throughout the disease course. We found that macrophage infiltration and microglia activation preceded detectable T-cell infiltration. Axonal loss was first evident at the acute phase of disease before demyelination was detected. Demyelination and axonal loss occurred after each relapse and correlated with increasing residual motor deficits in remission. The resulting lesions displayed evidence of demyelination, remyelination, axonal degeneration, and axon loss. After a series of 3 relapses, animals entered a chronic progressive phase with permanent paralysis and a relative absence of inflammation. Axonal loss continued in this phase, although demyelinated axons persisted. These findings indicate that experimental autoimmune encephalomyelitis in Biozzi ABH mice has important similarities to multiple sclerosis with a relapsing-remitting disease course followed by a secondary progressive phase; it is thus a suitable model in which to explore remyelination and neuroprotective therapies for multiple sclerosis.

Pharmacological and therapeutic secrets of plant and brain (endo)cannabinoids

Research on the chemistry and pharmacology of cannabinoids and endocannabinoids has reached enormous proportions, with approximately 15,000 articles on Cannabis sativa L. and cannabinoids and over 2,000 articles on endocannabinoids. The present review deals with the history of the Cannabis sativa L. plant, its uses, constituent compounds and their biogeneses, and similarity to compounds from Radula spp. In addition, details of the pharmacology of natural cannabinoids, as well as synthetic agonists and antagonists are presented. Finally, details regarding the pioneering isolation of the endocannabinoid anandamide, as well as the pharmacology and potential therapeutic uses of endocannabinoid congeners are presented.

The endocannabinoid system as a target for the treatment of motor dysfunction

There is evidence that cannabinoid-based medicines that are selective for different targets in the cannabinoid signalling system (e.g. receptors, inactivation mechanism, enzymes) might be beneficial in basal ganglia disorders, namely Parkinson's disease (PD) and Huntington's disease (HD). These benefits not only include the alleviation of specific motor symptoms [e.g. choreic movements with cannabinoid receptor type 1 (CB(1))/transient receptor potential vanilloid type 1 agonists in HD; bradykinesia with CB(1) antagonists and tremor with CB(1) agonists in PD], but also the delay of disease progression due to the neuroprotective properties demonstrated for cannabinoids (e.g. CB(1) agonists reduce excitotoxicity; CB(2) agonists limit the toxicity of reactive microglia; and antioxidant cannabinoids attenuate oxidative damage). In addition, extensive biochemical, anatomical, physiological and pharmacological studies have demonstrated that: (i) the different elements of the cannabinoid system are abundant in basal ganglia structures and they are affected by these disorders; (ii) the cannabinoid system plays a prominent role in basal ganglia function by modulating the neurotransmitters that operate in the basal ganglia circuits, both in healthy and pathological conditions; and (iii) the activation and/or inhibition of the cannabinoid system is associated with important motor responses that are maintained and even enhanced in conditions of malfunctioning and/or degeneration. In this article we will review the available data regarding the relationship between the cannabinoid system and basal ganglia activity, both in healthy and pathological conditions and will also try to identify future lines of research expected to increase current knowledge about the potential therapeutic benefits of targeting this system in PD, HD and other basal ganglia disorders.

Therapeutic potential of cannabis in pain medicine

Advances in cannabis research have paralleled developments in opioid pharmacology whereby a psychoactive plant extract has elucidated novel endogenous signalling systems with therapeutic significance. Cannabinoids (CBs) are chemical compounds derived from cannabis. The major psychotropic CB delta-9-tetrahydrocannabinol (Delta(9)-THC) was isolated in 1964 and the first CB receptor (CB(1)R) was cloned in 1990. CB signalling occurs via G-protein-coupled receptors distributed throughout the body. Endocannabinoids are derivatives of arachidonic acid that function in diverse physiological systems. Neuronal CB(1)Rs modulate synaptic transmission and mediate psychoactivity. Immune-cell CB(2) receptors (CB(2)R) may down-regulate neuroinflammation and influence cyclooxygenase-dependent pathways. Animal models demonstrate that CBRs play a fundamental role in peripheral, spinal, and supraspinal nociception and that CBs are effective analgesics. Clinical trials of CBs in multiple sclerosis have suggested a benefit in neuropathic pain. However, human studies of CB-mediated analgesia have been limited by study size, heterogeneous patient populations, and subjective outcome measures. Furthermore, CBs have variable pharmacokinetics and can manifest psychotropism. They are currently licensed as antiemetics in chemotherapy and can be prescribed on a named-patient basis for neuropathic pain. Future selective peripheral CB(1)R and CB(2)R agonists will minimize central psychoactivity and may synergize opioid anti-nociception. This review discusses the basic science and clinical aspects of CB pharmacology with a focus on pain medicine.

Current status of cannabis treatment of multiple sclerosis with an illustrative case presentation of a patient with MS, complex vocal tics, paroxysmal dystonia, and marijuana dependence treated with dronabinol

Pain, spasticity, tremor, spasms, poor sleep quality, and bladder and bowel dysfunction, among other symptoms, contribute significantly to the disability and impaired quality of life of many patients with multiple sclerosis (MS). Motor symptoms referable to the basal ganglia, especially paroxysmal dystonia, occur rarely and contribute to the experience of distress. A substantial percentage of patients with MS report subjective benefit from what is often illicit abuse of extracts of the Cannabis sativa plant; the main cannabinoids include delta-9-tetrahydrocannabinol (delta9-THC) and cannabidiol. Clinical trials of cannabis plant extracts and synthetic delta9-THC provide support for therapeutic benefit on at least some patient self-report measures. An illustrative case is presented of a 52-year-old woman with MS, paroxysmal dystonia, complex vocal tics, and marijuana dependence. The patient was started on an empirical trial of dronabinol, an encapsulated form of synthetic delta9-THC that is usually prescribed as an adjunctive medication for patients undergoing cancer chemotherapy. The patient reported a dramatic reduction of craving and illicit use; she did not experience the "high" on the prescribed medication. She also reported an improvement in the quality of her sleep with diminished awakenings during the night, decreased vocalizations, and the tension associated with their emission, decreased anxiety and a decreased frequency of paroxysmal dystonia.