Cannabinoids and Neurogenesis: The Promised Solution for Neurodegeneration?

molecules-logo“The concept of neurons as irreplaceable cells does not hold true today. Experiments and evidence of neurogenesis, also, in the adult brain give hope that some compounds or drugs can enhance this process, helping to reverse the outcomes of diseases or traumas that once were thought to be everlasting.

Cannabinoids, both from natural and artificial origins, already proved to have several beneficial effects (e.g., anti-inflammatory, anti-oxidants and analgesic action), but also capacity to increase neuronal population, by replacing the cells that were lost and/or regenerate a damaged nerve cell.

Neurogenesis is a process which is not highly represented in literature as neuroprotection, though it is as important as prevention of nervous system damage, because it can represent a possible solution when neuronal death is already present, such as in neurodegenerative diseases.

The aim of this review is to resume the experimental evidence of phyto- and synthetic cannabinoids effects on neurogenesis, both in vitro and in vivo, in order to elucidate if they possess also neurogenetic and neurorepairing properties.”

“The current results of cannabinoids effects on neurogenesis are encouraging, and it is expectable that the amount of evidence continues to increase in the future with other experiments.”

Δ9-Tetrahydrocannabivarin (THCV): a commentary on potential therapeutic benefit for the management of obesity and diabetes

figure1“Δ9-Tetrahydrocannabivarin (THCV) is a cannabis-derived compound with unique properties that set it apart from the more common cannabinoids, such as Δ9-tetrahydrocannabinol (THC). The main advantage of THCV over THC is the lack of psychoactive effects. In rodent studies, THCV decreases appetite, increases satiety, and up-regulates energy metabolism, making it a clinically useful remedy for weight loss and management of obesity and type 2 diabetic patients. The distinctions between THCV and THC in terms of glycemic control, glucose metabolism, and energy regulation have been demonstrated in previous studies. Also, the effect of THCV on dyslipidemia and glycemic control in type 2 diabetics showed reduced fasting plasma glucose concentration when compared to a placebo group. In contrast, THC is indicated in individuals with cachexia. However, the uniquely diverse properties of THCV provide neuroprotection, appetite suppression, glycemic control, and reduced side effects, etc.; therefore, making it a potential priority candidate for the development of clinically useful therapies in the future. Hopefully, THCV could provide an optional platform for the treatment of life-threatening diseases.”

“The psychoactive effects of THC in marijuana are the main reasons for its classification as a Schedule I substance, even though it is the THC that the U.S. Food and Drug Administration (FDA) approved for appetite stimulation and weight gain. In contrast to THC, clinical and therapeutic advantages of THCV regarding its lack of psychoactive effects in human studies are of great value in pharmacotherapy. It is envisioned that the unique and diverse characteristics of THCV could be explored for further development into clinically useful medicines for the treatment of life-threatening diseases.”

Δ 9 -Tetrahydrocannabinol promotes functional remyelination in the mouse brain

British Journal of Pharmacology“Background and purpose: Research on demyelinating disorders aims to find novel molecules that are able to induce oligodendrocyte precursor cell differentiation to promote central nervous system remyelination and functional recovery.

Δ9 -Tetrahydrocannabinol (THC), the most prominent active constituent of the hemp plant Cannabis sativa, confers neuroprotection in animal models of demyelination. However, the possible effect of THC on myelin repair has never been studied.

Experimental approach: By using oligodendroglia-specific reporter mouse lines in combination with two models of toxin-induced demyelination, we analysed the effect of THC on the processes of oligodendrocyte regeneration and functional remyelination.

Key results: We show that THC administration enhanced oligodendrocyte regeneration, white matter remyelination and motor function recovery. THC also promoted axonal remyelination in organotypic cerebellar cultures. THC remyelinating action relied on the induction of oligodendrocyte precursor differentiation upon cell cycle exit and via CB1 cannabinoid receptor activation.

Conclusions and implications: Overall, our study identifies THC administration as a promising pharmacological strategy aimed to promote functional CNS remyelination in demyelinating disorders.”

“Our study provides a novel therapeutic advantage of THC-based interventions in multiple sclerosis by promoting remyelination and functional recovery. New clinical trials with improved designs on cannabinoids in people with multiple sclerosis are needed now, considering these compounds as potential remyelinating/disease-modifying drugs to try to overcome previous failures. Our work also suggests that at least part of the neuroprotective action of phytocannabinoids in multiple sclerosis animal models and potentially in patients as well may be due to an enhanced CNS remyelination. Finally, this study also identifies THC as a potent inductor of oligodendrocyte progenitor cell differentiation under demyelination in mice, opening the possibility for this molecule to become a candidate drug to promote oligodendrocyte regeneration and remyelination in the treatment of demyelinating disorders.”

The impact of cannabinoid type 2 receptors (CB2Rs) in neuroprotection against neurological disorders

 Acta Pharmacologica Sinica“Cannabinoids have long been used for their psychotropic and possible medical properties of symptom relief. In the past few years, a vast literature shows that cannabinoids are neuroprotective under different pathological situations.

Most of the effects of cannabinoids are mediated by the well-characterized cannabinoid receptors, the cannabinoid type 1 receptor (CB1R) and cannabinoid type 2 receptor (CB2R). Even though CB1Rs are highly expressed in the central nervous system (CNS), the adverse central side effects and the development of tolerance resulting from CB1R activation may ultimately limit the clinical utility of CB1R agonists. In contrast to the ubiquitous presence of CB1Rs, CB2Rs are less commonly expressed in the healthy CNS but highly upregulated in glial cells under neuropathological conditions.

Experimental studies have provided robust evidence that CB2Rs seem to be involved in the modulation of different neurological disorders. In this paper, we summarize the current knowledge regarding the protective effects of CB2R activation against the development of neurological diseases and provide a perspective on the future of this field. A better understanding of the fundamental pharmacology of CB2R activation is essential for the development of clinical applications and the design of novel therapeutic strategies.”

A Cannabinoid Type 2 (CB2) Receptor Agonist Augments NOS-Dependent Responses of Cerebral Arterioles during Type 1 Diabetes

Microvascular Research “While activation of cannabinoid (CB2) receptors has been shown to be neuroprotective, no studies have examined whether this neuroprotection is directed at cerebral arterioles and no studies have examined whether activation of CB2 receptors can rescue cerebrovascular dysfunction during a chronic disease state such as type 1 diabetes (T1D).

Our goal was to test the hypothesis that administration of a CB2 agonist (JWH-133) would improve impaired endothelial (eNOS)- and neuronal (nNOS)- dependent dilation of cerebral arterioles during T1D.

In vivo diameter of cerebral arterioles in nondiabetic and T1D rats was measured in response to an eNOS-dependent agonist (adenosine 5′-diphosphate; ADP), an nNOS-dependent agonist (N-methyl-D-aspartate; NMDA), and an NOS-independent agonist (nitroglycerin) before and 1 hour following JWH-133 (1 mg/kg IP). Dilation of cerebral arterioles to ADP and NMDA was greater in nondiabetic than in T1D rats.

Treatment with JWH-133 increased responses of cerebral arterioles to ADP and NMDA in both nondiabetic and T1D rats. Responses of cerebral arterioles to nitroglycerin were similar between nondiabetic and T1D rats, and JWH-133 did not influence responses to nitroglycerin in either group. The restoration in responses to the agonists by JWH-133 could be inhibited by treatment with a specific inhibitor of CB2 receptors (AM-630; 3 mg/kg IP).

Thus, activation of CB2 receptors can potentiate reactivity of cerebral arterioles during physiologic and pathophysiologic states. We speculate that treatment with CB2 receptor agonists may have potential therapeutic benefits for the treatment of cerebral vascular diseases via a mechanism that can increase cerebral blood flow.”

“Activation of CB2 receptors improves cerebral vascular function. Activation of CB2 receptors improves responses in type 1 diabetes. We speculate that treatment with CB2 receptor agonists may have potential therapeutic benefits for the treatment of cerebral vascular disease that can contribute to the pathogenesis of stroke.”

Investigating the cumulative effects of Δ9-tetrahydrocannabinol and repetitive mild traumatic brain injury on adolescent rats

 Issue Cover“The prevalence of mild traumatic brain injury is highest amongst the adolescent population and can lead to complications including neuroinflammation and excitotoxicity.

Δ9-Tetrahydrocannabinol, the main psychoactive component of cannabis, is known to have anti-inflammatory properties and serves as a neuroprotective agent against excitotoxicity.

Thus, we investigated the effects of Δ9-tetrahydrocannabinol on recovery when administered either prior to or following repeated mild brain injuries.

We hypothesized that, in both experiments, Δ9-tetrahydrocannabinol administration would provide neuroprotection against mild injury outcomes and confer therapeutic benefit.

Δ9-Tetrahydrocannabinol administration following repeated mild traumatic brain injury was beneficial to three of the six behavioural outcomes affected by injury (reducing anxiety and depressive-like behaviours while also mitigating injury-induced deficits in short-term working memory). Δ9-Tetrahydrocannabinol administration following injury also showed beneficial effects on the expression of Cnr1Comt and Vegf-2R in the hippocampus, nucleus accumbens and prefrontal cortex.

There were no notable benefits of Δ9-tetrahydrocannabinol when administered prior to injury, suggesting that Δ9-tetrahydrocannabinol may have potential therapeutic benefit on post-concussive symptomology when administered post-injury, but not pre-injury.”

 “Overall, this study suggests that THC has potential therapeutic efficacy for the treatment of RmTBI-induced symptomology but requires additional examination.”

Cannabinoid-profiled agents improve cell survival via reduction of oxidative stress and inflammation, and Nrf2 activation in a toxic model combining hyperglycemia+Aβ 1-42 peptide in rat hippocampal neurons

Neurochemistry International “Alzheimer’s disease (AD) is a multifactorial neurodegenerative disorder linked to various converging toxic mechanisms. Evidence suggests that hyperglycemia induces oxidative stress, mitochondrial dysfunction, inflammation and excitotoxicity, all of which play important roles in the onset and progression of AD pathogenesis.

The endocannabinoid system (ECS) orchestrates major physiological responses, including neuronal plasticity, neuroprotection, and redox homeostasis, to name a few. The multi-targeted effectiveness of the ECS emerges as a potential approach to treat AD.

Here we characterized the protective properties of the endocannabinoids arachidonylethanolamide (AEA) and 2-arachidonoylglycerol (2-AG), the synthetic cannabinoids CP 55-940 and WIN 55,212-2, and the fatty acid amide hydrolase (FAAH) inhibitor URB597, on a combined hyperglycemia+oligomeric amyloid β peptide (Aβ1-42) neurotoxic model in primary hippocampal neurons which exhibit several AD features.

All agents tested preserved cell viability and stimulated mitochondrial membrane potential, while reducing all the evaluated toxic endpoints in a differential manner, with URB597 showing the highest efficacy. The neuroprotective efficacy of all cannabinoid agents, except for URB597, led to partial recruitment of specific antioxidant activity and Nrf2 pathway regulation.

Our results support the neuroprotective potential of these agents at low concentrations against the damaging effects of GLU+Aβ1-42, affording new potential modalities for the design of AD therapies.”

“All cannabinoid agents prevented the GLU + Aβ1-42 toxicity in a differential manner. All cannabinoid agents recruited Nrf2 signaling to protect cells.”

The Treatment of Cognitive, Behavioural and Motor Impairments from Brain Injury and Neurodegenerative Diseases through Cannabinoid System Modulation-Evidence from In Vivo Studies

jcm-logo“Neurological disorders such as neurodegenerative diseases or traumatic brain injury are associated with cognitive, motor and behavioural changes that influence the quality of life of the patients. Although different therapeutic strategies have been developed and tried until now to decrease the neurological decline, no treatment has been found to cure these pathologies.

In the last decades, the implication of the endocannabinoid system in the neurological function has been extensively studied, and the cannabinoids have been tried as a new promising potential treatment. In this study, we aimed to overview the recent available literature regarding in vivo potential of natural and synthetic cannabinoids with underlying mechanisms of action for protecting against cognitive decline and motor impairments.

The results of studies on animal models showed that cannabinoids in traumatic brain injury increase neurobehavioral function, working memory performance, and decrease the neurological deficit and ameliorate motor deficit through down-regulation of pro-inflammatory markers, oedema formation and blood-brain barrier permeability, preventing neuronal cell loss and up-regulating the levels of adherence junction proteins.

In neurodegenerative diseases, the cannabinoids showed beneficial effects in decreasing the motor disability and disease progression by a complex mechanism targeting more signalling pathways further than classical receptors of the endocannabinoid system. In light of these results, the use of cannabinoids could be beneficial in traumatic brain injuries and multiple sclerosis treatment, especially in those patients who display resistance to conventional treatment.”

Hydroxycinnamic acid derivatives isolated from hempseed and their effects on central nervous system enzymes

 Publication Cover“New neuroprotective treatments of natural origin are being investigated. Both, plant extracts and isolated compounds have shown bioactive effects.

Hempseed is known for its composition of fatty acids, proteins, fibre, vitamins, as well as a large number of phytochemical compounds. After a defatting process of the seeds, hydroxycinnamic acids and its amine derivatives are the majoritarian compounds in an ethyl acetate fraction (EAF).

In the present study, we investigated in vitro effect on neuronal enzymes: MAO-A, MAO-B, tyrosinase and acetylcholinesterase. Besides, the effect of EAF on striatal biogenic amines in mice was evaluated. Both, EAF and isolated compounds (N-trans-caffeoyltyramine and N-trans-coumaroyltyramine), showed inhibitory action on MAO-A, MAO-B and tyrosinase. Furthermore, an increasing of biogenic amines was observed in the corpus striatum of the mice, after administration of EAF.

These findings show that EAF and the hydroxycinnamic acid derivatives may represent a potential treatment in degenerative neuronal diseases.”

Neuroprotection or Neurotoxicity of Illicit Drugs on Parkinson’s Disease

life-logo“Parkinson’s Disease (PD) is currently the most rapid growing neurodegenerative disease and over the past generation, its global burden has more than doubled. The onset of PD can arise due to environmental, sporadic or genetic factors. Nevertheless, most PD cases have an unknown etiology.

Chemicals, such as the anthropogenic pollutant 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and amphetamine-type stimulants, have been associated with the onset of PD. Conversely, cannabinoids have been associated with the treatment of the symptoms’. PD and medical cannabis is currently under the spotlight, and research to find its benefits on PD is on-going worldwide.”