Metabolic endotoxemia promotes neuroinflammation after focal cerebral ischemia

Lipopolysaccharide (LPS) is a major component of the outer membrane of Gram-negative bacteria and a potent inflammatory stimulus for the innate immune response via toll-like receptor (TLR) 4 activation. Type 2 diabetes is associated with changes in gut microbiota and impaired intestinal barrier functions, leading to translocation of microbiota-derived LPS into the circulatory system, a condition referred to as metabolic endotoxemia. We investigated the effects of metabolic endotoxemia after experimental stroke with transient middle cerebral artery occlusion (MCAO) in a murine model of type 2 diabetes (db/db) and phenotypically normal littermates (db/+). Compared to db/+ mice, db/db mice exhibited an altered gut microbial composition, increased intestinal permeability, and higher plasma LPS levels. In addition, db/db mice presented increased infarct volumes and higher expression levels of LPS, TLR4, and inflammatory cytokines in the ischemic brain, as well as more severe neurological impairments and reduced survival rates after MCAO. Oral administration of a non-absorbable antibiotic modulated the gut microbiota and improved metabolic endotoxemia and stroke outcomes in db/db mice; these effects were associated with reduction of LPS levels and neuroinflammation in the ischemic brain. These data suggest that targeting metabolic endotoxemia may be a novel potential therapeutic strategy to improve stroke outcomes.     

Effects of cannabidiol on schizophrenia-like symptoms in people who use cannabis

Cannabis contains various cannabinoids, two of which have almost opposing actions: Delta9-tetrahydrocannabinol (Delta9-THC) is psychotomimetic, whereas cannabidiol (CBD) has antipsychotic effects. Hair samples were analysed to examine levels of Delta9-THC and CBD in 140 individuals. Three clear groups emerged: ;THC only', ;THC+CBD' and those with no cannabinoid in hair. The THC only group showed higher levels of positive schizophrenia-like symptoms compared with the no cannabinoid and THC+CBD groups, and higher levels of delusions compared with the no cannabinoid group. This provides evidence of the divergent properties of cannabinoids and has important implications for research into the link between cannabis use and psychosis.     

Microbial lipopolysaccharide-induced inflammation contributes to cognitive impairment and white matter lesion progression in diet-induced obese mice with chronic cerebral hypoperfusion

Aims

White matter lesions (WMLs) are involved in the pathological processes leading to cognitive decline and dementia. We examined the mechanisms underlying the exacerbation of ischemia-induced cognitive impairment and WMLs by diet-induced obesity, including lipopolysaccharide (LPS)-triggered neuroinflammation via toll-like receptor (TLR) 4.

Methods

Wild-type (WT) and TLR4-knockout (KO) C57BL/6 mice were fed a high-fat diet (HFD) or low-fat diet (LFD), and subjected to bilateral carotid artery stenosis (BCAS). Diet groups were compared for changes in gut microbiota, intestinal permeability, systemic inflammation, neuroinflammation, WML severity, and cognitive dysfunction.

Results

In WT mice, HFD induced obesity and increased cognitive impairment and WML severity compared with LFD-fed mice following BCAS. HFD caused gut dysbiosis and increased intestinal permeability, and plasma LPS and pro-inflammatory cytokine concentrations. Furthermore, HFD-fed mice had higher LPS levels and higher neuroinflammatory status, including increased TLR4 expression, in WMLs. In TLR4-KO mice, HFD also caused obesity and gut dysbiosis but did not increase cognitive impairment or WML severity after BCAS. No difference was found between HFD- and LFD-fed KO mice for LPS levels or inflammatory status in either plasma or WMLs.

Conclusion

Inflammation triggered by LPS–TLR4 signaling may mediate obesity-associated exacerbation of cognitive impairment and WMLs from brain ischemia.     

Impairment of ADP-induced platelet aggregation by hashish components.

ADP-induced aggregation of washed human platelets is inhibited by the hashish components delta1-tetrahydrocannabinol (THC) and cannabidiol (CBD). The inhibition is counteracted by added ADP. When the cannabinoids are present at concentrations higher than 10(-5)M, the platelets aggregate non-reversibly, independently of an added inducer, apparently due to lysis and release of endogenous inducers. THC is clearly more potent than CBD in exhibiting the biphasic effect. Collagen- and thrombin-induced aggregation of washed platelets are hardly affected by the cannabinoids. THC and CBD also curtail ADP-induced reversible aggregation in platelet-rich plasma, while serotonin release and irreversible aggregation, caused by either ADP, collagen or thrombin, are not affected by the cannabinoids in platelet-rich plasma. The data point to associated sites for ADP and the cannabinoids on the platelet membrane.     

Pharmacology of cannabinoids in the treatment of epilepsy

The use of cannabis products in the treatment of epilepsy has long been of interest to researchers and clinicians alike; however, until recently very little published data were available to support its use. This article summarizes the available scientific data of pharmacology from human and animal studies on the major cannabinoids which have been of interest in the treatment of epilepsy, including ∆ 9-tetrahydrocannabinol (∆ 9-THC), cannabidiol (CBD), ∆ 9-tetrahydrocannabivarin (∆ 9-THCV), cannabidivarin (CBDV), and ∆ 9-tetrahydrocannabinolic acid (Δ9-THCA). It has long been known that ∆ 9-THC has partial agonist activity at the endocannabinoid receptors CB1 and CB2, though it also binds to other targets which may modulate neuronal excitability and neuroinflammation. The actions of Δ9-THCV and Δ9-THCA are less well understood. In contrast to ∆ 9-THC, CBD has low affinity for CB1 and CB2 receptors and other targets have been investigated to explain its anticonvulsant properties including TRPV1, voltage gated potassium and sodium channels, and GPR55, among others. We describe the absorption, distribution, metabolism, and excretion of each of the above mentioned compounds. Cannabinoids as a whole are very lipophilic, resulting in decreased bioavailability, which presents challenges in optimal drug delivery. Finally, we discuss the limited drug-drug interaction data available on THC and CBD. As cannabinoids and cannabis-based products are studied for efficacy as anticonvulsants, more investigation is needed regarding the specific targets of action, optimal drug delivery, and potential drug-drug interactions.This article is part of a Special Issue titled Cannabinoids and Epilepsy     

Heat-sterilized Bifidobacterium breve prevents depression-like behavior and interleukin-1β expression in mice exposed to chronic social defeat stress

Major depressive disorder (MDD) is a common and serious psychiatric disease that involves brain inflammation. Bifidobacterium breve is commonly used as a probiotic and was shown to improve colitis and allergic diseases by suppressing the inflammatory response. Heat-sterilized B. breve has beneficial effects on inflammation. We hypothesize, therefore, that this probiotic might reduce depression symptoms. We tested this is a mouse model of social defeat stress. C57BL/6J mice exposed to chronic social defeat stress (CSDS) for five consecutive days developed a mild depression-like behavior characterized by a social interaction impairment. CSDS also altered the gut microbiota composition, such as increased abundance of Bacilli, Bacteroidia, Mollicutes, and Verrucomicrobiae classes and decreased Erysipelotrichi class. The prophylactic effect of heat-sterilized B. breve as a functional food ingredient was evaluated on the depression-like behavior in mice. The supplementation started two weeks before and lasted two weeks after the last exposure to CSDS. Two weeks after CSDS, the mice showed deficits in social interaction and increased levels of inflammatory cytokines, including interleukin-1β (IL-1β) in the prefrontal cortex (PFC) and hippocampus (HIP). Heat-sterilized B. breve supplementation significantly prevented social interaction impairment, suppressed IL-1β increase in the PFC and HIP, and modulated the alteration of the gut microbiota composition induced by CSDS. These findings suggest that heat-sterilized B. breve prevents depression-like behavior and IL-1β expression induced by CSDS through modulation of the gut microbiota composition in mice. Therefore, heat-sterilized B. breve used as an ingredient of functional food might prevent MDD.     

Maternal immune activation in late gestation increases neuroinflammation and aggravates experimental autoimmune encephalomyelitis in the offspring

Multiple sclerosis (MS) is characterized by an autoimmune response against myelin antigens driven by autoreactive T cells. Several lines of evidence indicate that environmental factors, such as previous infection, can influence and trigger autoimmune responses. However, the importance of the gestational period, particularly under inflammatory conditions, on the modulation of MS and related neuroinflammation by the offspring is unknown. This study aimed to evaluate the impact of prenatal exposure to lipopolysaccharide (LPS) during late gestation on the neuroinflammatory response in primary mixed glial cultures and on the progression of experimental autoimmune encephalomyelitis (EAE, an animal model of MS) in the offspring. LPS (Escherichia coli 0127:B8, 120 μg/kg) was administered intraperitoneally to pregnant C57BL/6J mice on gestational day 17, and the offspring were assigned to two experiments: (1) mixed glial cultures generated using the brain of neonates, stimulated in vitro with LPS, and (2) adult offspring immunized with MOG_35–55. The EAE clinical symptoms were followed for 30 days. Different sets of animals were sacrificed either during the onset (7 days post-immunization [p.i.]), when spleen and lymph nodes were collected, or the peak of disease (20 days p.i.), when CNS were collected for flow cytometry, cytokine production, and protein/mRNA-expression analysis. The primary CNS cultures from the LPS-treated group produced exaggerated amounts of IL-6, IL-1β and nitrites after in vitro stimulus, while IL-10 production was lowered compared to the data of the control group. Prenatal exposure to LPS worsened EAE disease severity in adult offspring, and this worsening was linked to increased CNS-infiltrating macrophages, Th1 cells and Th17 cells at the peak of EAE severity; additionally, exacerbated gliosis was evidenced in microglia (MHC II) and astrocytes (GFAP protein level and immunoreactivity). The IL-2, IL-6 and IL-17 levels in the spleen and lymph nodes were increased in the offspring of the LPS-exposed dams. Our results indicate that maternal immune activation during late gestation predispose the offspring to increased neuroinflammation and potentiate the autoimmune response and clinical manifestation of EAE.     

Sex difference in prebiotics on gut and blood–brain barrier dysfunction underlying stress-induced anxiety and depression

Background

Most of the previous studies have demonstrated the potential antidepressive and anxiolytic role of prebiotic supplement in male subjects, yet few have females enrolled. Herein, we explored whether prebiotics administration during chronic stress prevented depression-like and anxiety-like behavior in a sex-specific manner and the mechanism of behavioral differences caused by sex.

Methods

Female and male C57 BL/J mice on normal diet were supplemented with or without a combination of fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) during 3- and 4-week chronic restraint stress (CRS) treatment, respectively. C57 BL/J mice on normal diet without CRS were used as controls. Behavior consequences, gut microbiota, dysfunction of gut and brain–blood barriers, and inflammatory profiles were measured.

Results

In the 3rd week, FOS + GOS administration attenuated stress-induced anxiety-like behavior in female, but not in male mice, and the anxiolytic effects in males were observed until the 4th week. However, protective effects of prebiotics on CRS-induced depression were not observed. Changes in the gene expression of tight junction proteins in the distal colon and hippocampus, and decreased number of colon goblet cells following CRS were restored by prebiotics only in females. In both female and male mice, prebiotics alleviated stress-induced BBB dysfunction and elevation in pro-inflammatory cytokines levels, and modulated gut microbiota caused by stress. Furthermore, correlation analysis revealed that anxiety-like behaviors were significantly correlated with levels of pro-inflammatory cytokines and gene expression of tight junction proteins in the hippocampus of female mice, and the abundance of specific gut microbes was also correlated with anxiety-like behaviors, pro-inflammatory cytokines, and gene expression of tight junction proteins in the hippocampus of female mice.

Conclusion

Female mice were more vulnerable to stress and prebiotics than males. The gut microbiota, gut and blood–brain barrier, and inflammatory response may mediate the protective effects of prebiotics on anxiety-like behaviors in female mice.     

A double-blind, randomized, placebo-controlled, parallel-group study of THC/CBD oromucosal spray in combination with the existing treatment regimen, in the relief of central neuropathic pain in patients with multiple sclerosis

Central neuropathic pain (CNP) occurs in many multiple sclerosis (MS) patients. The provision of adequate pain relief to these patients can very difficult. Here we report the first phase III placebo-controlled study of the efficacy of the endocannabinoid system modulator delta-9-tetrahydrocannabinol (THC)/cannabidiol (CBD) oromucosal spray (USAN name, nabiximols; Sativex, GW Pharmaceuticals, Salisbury, Wiltshire, UK), to alleviate CNP. Patients who had failed to gain adequate analgesia from existing medication were treated with THC/CBD spray or placebo as an add-on treatment, in a double-blind manner, for 14 weeks to investigate the efficacy of the medication in MS-induced neuropathic pain. This parallel-group phase of the study was then followed by an 18-week randomized-withdrawal study (14-week open-label treatment period plus a double-blind 4-week randomized-withdrawal phase) to investigate time to treatment failure and show maintenance of efficacy. A total of 339 patients were randomized to phase A (167 received THC/CBD spray and 172 received placebo). Of those who completed phase A, 58 entered the randomized-withdrawal phase. The primary endpoint of responder analysis at the 30 % level at week 14 of phase A of the study was not met, with 50 % of patients on THC/CBD spray classed as responders at the 30 % level compared to 45 % of patients on placebo (p = 0.234). However, an interim analysis at week 10 showed a statistically significant treatment difference in favor of THC/CBD spray at this time point (p = 0.046). During the randomized-withdrawal phase, the primary endpoint of time to treatment failure was statistically significant in favor of THC/CBD spray, with 57 % of patients receiving placebo failing treatment versus 24 % of patients from the THC/CBD spray group (p = 0.04). The mean change from baseline in Pain Numerical Rating Scale (NRS) (p = 0.028) and sleep quality NRS (p = 0.015) scores, both secondary endpoints in phase B, were also statistically significant compared to placebo, with estimated treatment differences of ?0.79 and 0.99 points, respectively, in favor of THC/CBD spray treatment. The results of the current investigation were equivocal, with conflicting findings in the two phases of the study. While there were a large proportion of responders to THC/CBD spray treatment during the phase A double-blind period, the primary endpoint was not met due to a similarly large number of placebo responders. In contrast, there was a marked effect in phase B of the study, with an increased time to treatment failure in the THC/CBD spray group compared to placebo. These findings suggest that further studies are required to explore the full potential of THC/CBD spray in these patients.     

Myelin basic protein-specific T lymphocytes induce chronic relapsing experimental autoimmune encephalomyelitis in lymphocyte-deficient (SCID) mice

Myelin basic protein (BP)-specific T lymphocyte cell lines were selected from the lymph nodes (LN) of BP-immunized, H-2^d, CXJ-1 mice prior to the onset of clinical disease. These CD4+ T cells induced severe acute experimental autoimmune encephalomyelitis (EAE) in MHC-compatible (H-2^d), lymphocyte-deficient (SCID) mice (C.B-17scid/scid). The incidence of disease was much higher in immunodeficient SCID mice (71%) than in syngeneic immunocompetent CXJ-1 mice (5%). SCID mice with EAE had an acute progressive paralytic disease with inflammation and myelin loss detected in the spinal cord. Eighty-six percent (12/14) of mice followed for more than 2 weeks had 1 or more relapses of EAE. These results demonstrate that clinical remission and relapse of EAE can be induced by the single adoptive transfer of a LN-derived BP-specific T cell line in the absence of host-derived effector and regulatory lymphocytes. Furthermore, the data demonstrate that the pathogenic potential of BP-specific T cells is greater in lymphocyte-deficient SCID mice compared with immunocompetent mice, suggesting that autoreactive T cells are controlled by potent inhibitory mechanisms associated with regulatory lymphocytes. These results are relevant to mechanisms of disease remission and relapse mediated by lymphocytes involved in paralytic inflammatory diseases such as multiple sclerosis (MS).     

Acupuncture inhibits neuroinflammation and gut microbial dysbiosis in a mouse model of Parkinson’s disease

Growing evidences show that gut microbiota is associated with the pathogenesis of Parkinson’s disease (PD) and the gut-brain axis can be promising target for the development of the therapeutic strategies for PD. Acupuncture has been used to improve brain functions and inflammation in neurological disorders such as PD, and to recover the gastrointestinal dysfunctions in various gastrointestinal disorders. Thus, we investigated whether acupuncture could improve Parkinsonism and gut microbial dysbiosis induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine. First, we observed that acupuncture treatment at acupoints GB34 and ST36 could improve motor functions and comorbid anxiety in PD mice. Next, we found that acupuncture increased the levels of dopaminergic fibers and neurons in the striatum and the substantia nigra, respectively. Acupuncture also restored the overexpression of microglia and astrocyte as well as conversion of Bax and Bcl-2 expression in both the striatum and the substantia nigra, indicating that inflammatory responses and apoptosis were blocked by acupuncture. Additionally, via 16S rRNA sequence analysis, we observed that the relative abundance of 18 genera were changed in acupuncture-treated mice compared to the PD mice. Of them, Butyricimonas, Holdemania, Frisingicoccus, Gracilibacter, Phocea, and Aestuariispira showed significant correlations with anxiety as well as motor functions. Furthermore, the predicted functional analyses showed that acupuncture restored the physiology functions such as glutathione metabolism, methane metabolism, and PD pathway. In conclusion, we suggest that the effects of acupuncture on the enhanced motor function and the protection of the dopaminergic neurons may be associated with the regulation of the gut microbial dysbiosis and thus the inhibition of the neuroinflammation in the PD mice.     

Central inhibition of interleukin-6 trans-signaling during peripheral infection reduced neuroinflammation and sickness in aged mice

During systemic infection, inflammatory cytokines such as interleukin (IL)-6 are produced in excess in the brain of aged mice and induce severe behavioral deficits. However, no studies have examined how pro-inflammatory IL-6 trans-signaling is involved in the exaggerated production of IL-6 in the aged brain, nor the extent to which IL-6 trans-signaling affects other markers of neuroinflammation, adhesion molecules, and behavior. Therefore, this study investigated in aged mice the presence of IL-6 signaling subunits in microglia; the central effects of soluble gp130 (sgp130)—a natural inhibitor of the IL-6 trans-signaling pathway—on IL-6 production in microglia; and the effects of sgp130 given intracerebroventricularly (ICV) on neuroinflammation and sickness behavior caused by i.p. injection of lipopolysaccharide (LPS). Here we show that microglia isolated from aged mice have higher expression of IL-6 receptor (IL-6R) compared to microglia from adults; and the level of mRNA for ADAM17, the enzyme responsible for shedding membrane-bound IL-6R in trans-signaling, is higher in the hippocampus of aged mice compared to adults. Additionally, we show in aged mice that peripheral LPS challenge elicits a hyperactive IL-6 response in microglia, and selective blockade of trans-signaling by ICV injection of sgp130 mitigates this. The sgp130-associated inhibition of IL-6 was paralleled by amelioration of exaggerated and protracted sickness behavior in aged mice. Taken together, the results show that microglia are important regulators of the IL-6 trans-signaling response in the aged brain and sgp130 exerts an anti-inflammatory effect by inhibiting the pro-inflammatory arm of IL-6 signaling.     

Gut microbiota depletion from early adolescence in mice: Implications for brain and behaviour

Background: There is growing appreciation for the importance of bacteria in shaping brain development and behaviour. Adolescence and early adulthood are crucial developmental periods during which exposure to harmful environmental factors can have a permanent impact on brain function. Such environmental factors include perturbations of the gut bacteria that may affect gut–brain communication, altering the trajectory of brain development, and increasing vulnerability to psychiatric disorders. Here we assess the effects of gut bacterial depletion from weaning onwards on adult cognitive, social and emotional behaviours and markers of gut–brain axis dysfunction in mice. Methods: Mice were treated with a combination of antibiotics from weaning onwards and effects on behaviours and potential gut-brain axis neuromodulators (tryptophan, monoamines, and neuropeptides) and BDNF expression were assessed in adulthood. Results: Antibiotic-treatment depleted and restructured gut microbiota composition of caecal contents and decreased spleen weights in adulthood. Depletion of the gut microbiota from weaning onwards reduced anxiety, induced cognitive deficits, altered dynamics of the tryptophan metabolic pathway, and significantly reduced BDNF, oxytocin and vasopressin expression in the adult brain. Conclusions: Microbiota depletion from weaning onwards by means of chronic treatment with antibiotics in mice impacts on anxiety and cognitive behaviours as well as key neuromodulators of gut–brain communication in a manner that is similar to that reported in germ-free mice. This model may represent a more amenable alternative for germ-free mice in the assessment of microbiota modulation of behaviour. Finally, these data suggest that despite the presence of a normal gut microbiome in early postnatal life, reduced abundance and diversity of the gut microbiota from weaning influences adult behaviours and key neuromodulators of the microbiota–gut–brain axis suggesting that dysregulation of this axis in the post-weaning period may contribute to the pathogenesis of disorders associated with altered anxiety and cognition.     

β-Glucan attenuates cognitive impairment of APP/PS1 mice via regulating intestinal flora and its metabolites

Background

The intestinal flora has been shown to be involved in the progression of Alzheimer's disease (AD) and can be improved by β-glucan, a polysaccharide derived from Saccharomyces cerevisiae, which affects cognitive function through the intestinal flora. However, it is not known if this effect of β-glucan is involved in AD.

Method

This study used behavioral testing to measure cognitive function. After that, high-throughput 16 S rRNA gene sequencing and GC–MS were used to analyze the intestinal microbiota and metabolite SCFAs of AD model mice, and further explore the relationship between intestinal flora and neuroinflammation. Finally, the expressions of inflammatory factors in the mouse brain were detected by Western blot and Elisa methods.

Results

We found that appropriate supplementation of β-glucan during the progression of AD can improve cognitive impairment and reduce A β plaque deposition. In addition, supplementation of β-glucan can also promote changes in the composition of the intestinal flora, thereby changing the flora metabolites in the intestinal content and reduce the activation of inflammatory factors and microglia in the cerebral cortex and hippocampus through the brain-gut axis. While reducing the expression of inflammatory factors in the hippocampus and cerebral cortex, thereby controlling neuroinflammation.

Conclusion

The imbalance of the gut microbiota and metabolites plays a role in the progression of AD; β-glucan blocks the development of AD by improving the gut microbiota and its metabolites and reducing neuroinflammation. β-Glucan is a potential strategy for the treatment of AD by reshaping the gut microbiota and improving its metabolites.     

The diminishment of experimental autoimmune encephalomyelitis (EAE) by neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) therapy

The neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) plays an important role in immune privilege by its suppression of inflammation, and its induction of regulatory T cells. This finding led us to test the possibility that we can use alpha-MSH to suppress autoimmune diseases, and promote re-establishment of immune tolerance to autoantigens. To test this possibility, SJL mice with experimental autoimmune encephalomyelitis (EAE) were injected with alpha-MSH at the first signs of paralysis. The alpha-MSH-treated mice in comparison with untreated EAE mice had a profound diminishment in the severity and tempo of EAE. The spleen cells in alpha-MSH-treated EAE produced TGF-beta in response to PLP-antigen stimulation in contrast to untreated mice spleen cells that produced IFN-gamma. When the alpha-MSH-treated EAE mice were reimmunized there was a delay of a week before the second episode of EAE. Although this delay maybe because of the induction of TGF-beta-producing spleen cells by the alpha-MSH-treatment, it was not adequate to suppress IFN-gamma-production by PLP-antigen stimulated spleen cells from untreated mice, nor able to suppress the eventual second episode of EAE. Therefore, the injection of alpha-MSH at the onset of paralysis is extremely effective in diminishing the severity and tempo of EAE, and the subsequent induction of potential PLP-specific Treg cells suggests that an alpha-MSH therapy could be attempted as part of a therapeutic regiment to impose immunoregulation and immunosuppression on an autoimmune disease of the central nervous system.     

Potential antipsychotic properties of central cannabinoid (CB1) receptor antagonists

Δ⁹-Tetrahydrocannabinol (Δ⁹-THC), the principal psychoactive constituent of the Cannabis sativa plant, and other agonists at the central cannabinoid (CB₁) receptor may induce characteristic psychomotor effects, psychotic reactions and cognitive impairment resembling schizophrenia. These effects of Δ⁹-THC can be reduced in animal and human models of psychopathology by two exogenous cannabinoids, cannabidiol (CBD) and SR141716. CBD is the second most abundant constituent of Cannabis sativa that has weak partial antagonistic properties at the CB₁ receptor. CBD inhibits the reuptake and hydrolysis of anandamide, the most important endogenous CB₁ receptor agonist, and exhibits neuroprotective antioxidant activity. SR141716 is a potent and selective CB₁ receptor antagonist. Since both CBD and SR141716 can reverse many of the biochemical, physiological and behavioural effects of CB₁ receptor agonists, it has been proposed that both CBD and SR141716 have antipsychotic properties. Various experimental studies in animals, healthy human volunteers, and schizophrenic patients support this notion. Moreover, recent studies suggest that cannabinoids such as CBD and SR141716 have a pharmacological profile similar to that of atypical antipsychotic drugs. In this review, both preclinical and clinical studies investigating the potential antipsychotic effects of both CBD and SR141716 are presented together with the possible underlying mechanisms of action.     

A novel CB receptor GPR55 and its ligands are involved in regulation of gut movement in rodents

Background This study was to investigate the effects of the novel cannabinoid receptor – G protein‐coupled receptor 55 (GPR55) – and its ligands O‐1602 and cannabidiol (CBD) on gastrointestinal (GI) motility in rodents. Methods Lipopolysaccharide (LPS) was used in vivo to produce the model of septic ileus. The intestinal motility was measured by recording myoelectrical activity of jejunum in rats, and by measuring GI transit with a charcoal marker in mice, in presence of O‐1602 or CBD. Inflammatory response was assessed serologically and histologically. The expression and distribution of GPR55 in the different parts of rat intestine were investigated by real‐time PCR and immunohistochemistry. In vitro, the effects of the drugs on the GI movement were investigated by measuring the contraction of the intestinal muscle strips in organ bath, and the intracellular responses of the muscle cells with microelectrode technique. Key Results G protein‐coupled receptor 55 was expressed in different parts of rat intestine. Lipopolysaccharide significantly inhibited the intestinal motility, increased inflammatory cytokines and GPR55 expression. Pretreatment with CBD normalized LPS‐induced hypomotility and improved the inflammatory responses serologically and histologically. Both O‐1602 and CBD counteracted LPS‐induced disturbances of the gut contraction, but had no effect on the membrane potential of the muscle cells, while cannabinoid type 1 receptor antagonist AM251 and cannabinoid type 2 receptor antagonist AM630 increased the potential. Conclusions & Inferences G protein‐coupled receptor 55 existed throughout the whole intestine of rats. O‐1602 or CBD selectively normalized the motility disturbances. Possible mechanisms involved systemic anti‐inflammation and the regulation of myoelectrical activity of the intestine.     

Source of cannabinoids: what is available,what is used,and where does it come from?

Cannabis sativa L. is an ancient medicinal plant wherefrom over 120 cannabinoids are extracted. In the past two decades, there has been increasing interest in the therapeutic potential of cannabis‐based treatments for neurological disorders such as epilepsy, and there is now evidence for the medical use of cannabis and its effectiveness for a wide range of diseases. Cannabinoid treatments for pain and spasticity in patients with multiple sclerosis (Nabiximols) have been approved in several countries. Cannabidiol (CBD), in contrast to tetra‐hydro‐cannabidiol (THC), is not a controlled substance in the European Union, and over the years there has been increasing use of CBD‐enriched extracts and pure CBD for seizure disorders, particularly in children. No analytical controls are mandatory for CBD‐based products and a pronounced variability in CBD concentrations in commercialized CBD oil preparations has been identified. Randomized controlled trials of plant‐derived CBD for treatment of Lennox‐Gastaut syndrome (LGS) and Dravet syndrome (DS) have provided evidence of anti‐seizure effects, and in June 2018, CBD was approved by the Food and Drug Administration as an add‐on antiepileptic drug for patients two years of age and older with LGS or DS. Medical cannabis, with various ratios of CBD and THC and in different galenic preparations, is licensed in many European countries for several indications, and in July 2019, the European Medicines Agency also granted marketing authorisation for CBD in association with clobazam, for the treatment of seizures associated with LGS or DS. The purpose of this article is to review the availability of cannabis‐based products and cannabinoid‐based medicines, together with current regulations regarding indications in Europe (as of July 2019). The lack of approval by the central agencies, as well as social and political influences, have led to significant variation in usage between countries.     

Ultralow doses of cannabinoid drugs protect the mouse brain from inflammation‐induced cognitive damage

In our previous studies, we found that a single ultralow dose of tetrahydrocannabinol (THC; 0.002 mg/kg, three to four orders of magnitude lower than the conventional doses) protects the brain from different insults that cause cognitive deficits. Because various insults may trigger a neuroinflammatory response that leads to secondary damage to the brain, the current study tested whether this extremely low dose of THC could protect the brain from inflammation‐induced cognitive deficits. Mice received a single injection of THC (0.002 mg/kg) 48 hr before or 1–7 days after treatment with lipopolysccharide (LPS; 10 mg/kg) and were examined with the object recognition test 3 weeks later. LPS caused long‐lasting cognitive deficits, whereas the application of THC before or after LPS protected the mice from this LPS‐induced damage. The protective effect of THC was blocked by the cannabinoid (CB) 1 receptor antagonist SR14176A but not by the CB2 receptor antagonist SR141528 and was mimicked by the CB1 agonist ACEA but not by the CB2 agonist HU308. The protective effect of THC was also blocked by pretreatment with GW9662, indicating the involvement of peroxisome proliferator‐activated receptor‐γ. Biochemical examination of the brain revealed a long‐term (at least 7 weeks) elevation of the prostaglandin‐producing enzyme cyclooxygenase‐2 in the hippocampus and in the frontal cortex following the injection of LPS. Pretreatment with the extremely low dose of THC tended to attenuate this elevation. Our results suggest that an ultralow dose of THC that lacks any psychotrophic activity protects the brain from neuroinflammation‐induced cognitive damage and might be used as an effective drug for the treatment of neuroinflammatory conditions, including neurodegenerative diseases. © 2014 Wiley Periodicals, Inc.     

Placebo Effects in a Multiple Sclerosis Spasticity Enriched Clinical Trial with the Oromucosal Cannabinoid Spray (THC/CBD): Dimension and Possible Causes

Regulatory authorities admit clinical studies with an initial enrichment phase to select patients that respond to treatment before randomization (Enriched Design Studies; EDSs). The trial period aims to prevent long‐term drug exposure risks in patients with limited chances of improvement while optimizing costs. In EDSs for symptom control therapies providing early improvements and without a wash‐out period, it is difficult to show further improvements and thus large therapeutic gains versus placebo. Moreover, in trials with cannabinoids, the therapeutic gains can be further biased in the postenrichment randomized phase because of carryover and other effects. The aims of the present review article are to examine the placebo effects in the enrichment and postenrichment phases of an EDS with Δ⁹‐tetrahydrocannabinol and cannabidiol (THC/CBD) oromucosal spray in patients with multiple sclerosis (MS) spasticity and to discuss the possible causes of maintained efficacy after randomization in the placebo‐allocated patients. The overall mean therapeutic gain of THC/CBD spray over placebo in resistant MS spasticity after 16 weeks can be estimated as a ~1.27‐point improvement on the spasticity 0–10 Numerical Rating Scale (NRS; ~?20.1% of the baseline NRS score). We conclude that careful interpretation of the results of EDSs is required, especially when cannabinoid‐based medications are being investigated.