Cannabis and Cannabinoid Biology in Stroke

Neurological Complications of Cannabinoids

Cannabinoid use, particularly for recreational purposes, is increasing exponentially across all age groups, especially in younger populations, due to its perceived low risk and legalization. While cannabinoids may be largely considered as safe, there is mounting evidence of increased risk of systemic and neurological complications through their interaction with the poorly understood endocannabinoid receptor network within the central nervous system and other organ systems. Acute cannabinoid exposure can cause neuropsychiatric symptoms in addition to altering cerebral blood flow, leading to cerebrovascular complications such as ischemic stroke, subarachnoid hemorrhage, and reversible cerebral vasoconstriction syndrome (RCVS). Chronic use, particularly among adolescents, may be associated with increased risk of long-term cognitive deficits, schizophrenia, and other neuropsychiatric effects. Synthetic cannabinoids have increased potency, with reports of causing profound neurological complications including coma, seizures, posterior reversible encephalopathy syndrome, and RCVS. Despite increasing evidence, the quality of literature describing neurologic complications with cannabinoids remains limited to case series and retrospective cohort studies, with significant confounding factors such as concomitant use of other illicit drugs, limiting interpretation. In this review, we summarize the effect of cannabinoids on the neurologic system and associated neurological complications.

Potential of CBD Acting on Cannabinoid Receptors CB1 and CB2 in Ischemic Stroke

Stroke is one of the leading causes of death. It not only affects adult people but also many children. It is estimated that, every year, 15 million people suffer a stroke worldwide. Among them, 5 million people die, while 5 million people are left permanently disabled. In this sense, the research to find new treatments should be accompanied with new therapies to combat neuronal death and to avoid developing cognitive impairment and dementia. Phytocannabinoids are among the compounds that have been used by mankind for the longest period of history. Their beneficial effects such as pain regulation or neuroprotection are widely known and make them possible therapeutic agents with high potential. These compounds bind cannabinoid receptors CB1 and CB2. Unfortunately, the psychoactive side effect has displaced them in the vast majority of areas. Thus, progress in the research and development of new compounds that show efficiency as neuroprotectors without this psychoactive effect is essential. On the one hand, these compounds could selectively bind the CB2 receptor that does not show psychoactive effects and, in glia, has opened new avenues in this field of research, shedding new light on the use of cannabinoid receptors as therapeutic targets to combat neurodegenerative diseases such as Alzheimer's, Parkinson's disease, or stroke. On the other hand, a new possibility lies in the formation of heteromers containing cannabinoid receptors. Heteromers are new functional units that show new properties compared to the individual protomers. Thus, they represent a new possibility that may offer the beneficial effects of cannabinoids devoid of the unwanted psychoactive effect. Nowadays, the approval of a mixture of CBD (cannabidiol) and Δ9-THC (tetrahydrocannabinol) to treat the neuropathic pain and spasticity in multiple sclerosis or purified cannabidiol to combat pediatric epilepsy have opened new therapeutic possibilities in the field of cannabinoids and returned these compounds to the front line of research to treat pathologies as relevant as stroke.

Cannabis, Cannabinoids, and Stroke: Increased Risk or Potential for Protection-A Narrative Review

Worldwide, approximately 15 million people per year suffer from stroke. With about 5 million deaths, stroke is the second most common cause of death and a major cause of long-term disability. It is estimated that about 25% of people older than 85 years will develop stroke. Cannabis sativa and derived cannabinoids have been used for recreational and medical purposes for many centuries. However, due to the legal status in the past, research faced restrictions, and cannabis use was stigmatized for potential negative impacts on health. With the changes in legal status in many countries of the world, cannabis and cannabis-derived substances such as cannabinoids and terpenes have gained more interest in medical research. Several medical effects of cannabis have been scientifically proven, and potential risks identified. In the context of stroke, the role of cannabis is controversial. The negative impact of cannabis use on stroke has been reported through case reports and population-based studies. However, potential beneficial effects of specific cannabinoids are described in animal studies under certain conditions. In this narrative review, the existing body of evidence regarding the negative and positive impacts of cannabis use prior to stroke will be critically appraised.

Prevalence and impact of cannabis use disorder on acute ischemic stroke and subsequent mortality in elderly peripheral vascular disease patients: A population-based analysis in the USA (2016 - 2019)

BACKGROUND

Given current evidence linking peripheral atherosclerotic disease, also known as cannabis arteritis, and acute ischemic stroke (AIS) in individuals with cannabis use disorder (CUD), we investigated the frequency and implications of CUD in relation to AIS risk and outcomes among elderly patients with peripheral vascular disease (PVD).

METHODS

The National Inpatient Sample (2016-2019) was used to compare geriatric patients with PVD and cannabis use disorder CUD. CUD was correlated with AIS admissions. Adjusted multivariable regression models assessed in-hospital mortality rates.

RESULTS

Of 5,115,824 geriatric admissions with PVD, 50.6 % were male and 77.5 % were white. 21,405 admissions had cardiovascular and CUD co-occurrence. 19.7 % of CUD patients had diabetes mellitus (DM), compared to 33.7 % of non-CUD patients. Smoking and HTN rates were comparable between groups. Patients with CUD used more recreational drugs concurrently than those without CUD. AIS prevalence was 5.2 % in CUD patients and 4.0 % in controls (p < 0.001). In the geriatric population with PVD, the presence of CUD was found to be associated with increased odds of hospitalizations due to AIS, with an adjusted odds ratio (aOR) of 1.34 (95 % confidence interval [CI] 1.18-1.52, p < 0.001). All-cause in-hospital mortality was not statistically significant, with an aOR of 0.71 (95 %CI 0.36-1.37, p = 0.302). In our study, older patients with PVD and hypertension (aOR 1.73) had a greater risk of AIS. Intriguingly, when we analyzed AIS predictors in elderly PVD patients with concurrent tobacco use disorder, we identified a counterintuitive protective effect (aOR 0.58, 95 % CI 0.42-0.79, p < 0.001).

CONCLUSIONS

Our findings indicate that among geriatric patients with PVD and concurrent CUD, there is a notable 34 % risk of AIS. Importantly, this risk persists despite controlling for other CVD risk factors and substance use. Further investigations are warranted to elucidate and validate the intriguing phenomenon known as the smoker's paradox.

TRP Channels in Stroke

Ischemic stroke is a devastating disease that affects millions of patients worldwide. Unfortunately, there are no effective medications for mitigating brain injury after ischemic stroke. TRP channels are evolutionally ancient biosensors that detect external stimuli as well as tissue or cellular injury. To date, many members of the TRP superfamily have been reported to contribute to ischemic brain injury, including the TRPC subfamily (1, 3, 4, 5, 6, 7), TRPV subfamily (1, 2, 3, 4) and TRPM subfamily (2, 4, 7). These TRP channels share structural similarities but have distinct channel functions and properties. Their activation during ischemic stroke can be beneficial, detrimental, or even both. In this review, we focus on discussing the interesting features of stroke-related TRP channels and summarizing the underlying cellular and molecular mechanisms responsible for their involvement in ischemic brain injury.

Cannabinoids as Glial Cell Modulators in Ischemic Stroke: Implications for Neuroprotection

Stroke is the second leading cause of death worldwide following coronary heart disease. Despite significant efforts to find effective treatments to reduce neurological damage, many patients suffer from sequelae that impair their quality of life. For this reason, the search for new therapeutic options for the treatment of these patients is a priority. Glial cells, including microglia, astrocytes and oligodendrocytes, participate in crucial processes that allow the correct functioning of the neural tissue, being actively involved in the pathophysiological mechanisms of ischemic stroke. Although the exact mechanisms by which glial cells contribute in the pathophysiological context of stroke are not yet completely understood, they have emerged as potentially therapeutic targets to improve brain recovery. The endocannabinoid system has interesting immunomodulatory and protective effects in glial cells, and the pharmacological modulation of this signaling pathway has revealed potential neuroprotective effects in different neurological diseases. Therefore, here we recapitulate current findings on the potential promising contribution of the endocannabinoid system pharmacological manipulation in glial cells for the treatment of ischemic stroke.

Medical cannabis authorization and the risk of cardiovascular events: a longitudinal cohort study

Background

Cannabis is increasingly used for therapeutic purpose. However, its safety profile is not well known. This study assessed the risk of cardiovascular-related emergency department (ED) visit and hospitalization in adult patients authorized to use medical cannabis in Ontario, Canada from 2014 to 2017.

Methods

This is a longitudinal cohort study of patients who received medical cannabis authorization and followed-up in cannabis clinics, matched to population-based controls. The primary outcome was an ED visit or hospitalization for acute coronary syndrome (ACS) or stroke; and secondary outcome was for any cardiovascular event. Conditional Cox proportional hazards regression was used to assess the association between cannabis authorization and risk.

Results

18,653 cannabis patients were matched to 51,243 controls. During a median follow-up of 242 days, the incidence rates for ACS or stroke were 7.19/1000 person-years and 5.67/1000 person-years in the cannabis and controls group, respectively- adjusted hazard ratio (aHR) of 1.44 (95% CI 1.08–1.93). When stratified by sex, the association was only statistically significant among males: aHR 1.77 (1.23–2.56). For the secondary outcome (any CV events), the aHR was 1.47 (1.26–1.72). The aHR among males and females were 1.52 (1.24–1.86) and 1.41 (1.11–1.79), respectively. Tested interaction between cannabis authorization and sex was not significant (p > 0.05).

Conclusions

Medical cannabis authorization was associated with an increased risk of ED visits or hospitalization for CV events including stroke and ACS.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-021-02229-6.

The Endocannabinoid System: A Potential Target for the Treatment of Various Diseases

The Endocannabinoid System (ECS) is primarily responsible for maintaining homeostasis, a balance in internal environment (temperature, mood, and immune system) and energy input and output in living, biological systems. In addition to regulating physiological processes, the ECS directly influences anxiety, feeding behaviour/appetite, emotional behaviour, depression, nervous functions, neurogenesis, neuroprotection, reward, cognition, learning, memory, pain sensation, fertility, pregnancy, and pre-and post-natal development. The ECS is also involved in several pathophysiological diseases such as cancer, cardiovascular diseases, and neurodegenerative diseases. In recent years, genetic and pharmacological manipulation of the ECS has gained significant interest in medicine, research, and drug discovery and development. The distribution of the components of the ECS system throughout the body, and the physiological/pathophysiological role of the ECS-signalling pathways in many diseases, all offer promising opportunities for the development of novel cannabinergic, cannabimimetic, and cannabinoid-based therapeutic drugs that genetically or pharmacologically modulate the ECS via inhibition of metabolic pathways and/or agonism or antagonism of the receptors of the ECS. This modulation results in the differential expression/activity of the components of the ECS that may be beneficial in the treatment of a number of diseases. This manuscript in-depth review will investigate the potential of the ECS in the treatment of various diseases, and to put forth the suggestion that many of these secondary metabolites of Cannabis sativa L. (hereafter referred to as "C. sativa L." or "medical cannabis"), may also have potential as lead compounds in the development of cannabinoid-based pharmaceuticals for a variety of diseases.

Cannabis and Inflammation in HIV: A Review of Human and Animal Studies

Persistent inflammation occurs in people with HIV (PWH) and has many downstream adverse effects including myocardial infarction, neurocognitive impairment and death. Because the proportion of people with HIV who use cannabis is high and cannabis may be anti-inflammatory, it is important to characterize the impact of cannabis use on inflammation specifically in PWH. We performed a selective, non-exhaustive review of the literature on the effects of cannabis on inflammation in PWH. Research in this area suggests that cannabinoids are anti-inflammatory in the setting of HIV. Anti-inflammatory actions are mediated in many cases through effects on the endocannabinoid system (ECS) in the gut, and through stabilization of gut–blood barrier integrity. Cannabidiol may be particularly important as an anti-inflammatory cannabinoid. Cannabis may provide a beneficial intervention to reduce morbidity related to inflammation in PWH.

Psychedelics for Brain Injury: A Mini-Review

Objective: Stroke and traumatic brain injury (TBI) are among the leading causes of disability. Even after engaging in rehabilitation, nearly half of patients with severe TBI requiring hospitalization are left with major disability. Despite decades of investigation, pharmacologic treatment of brain injury is still a field in its infancy. Recent clinical trials have begun into the use of psychedelic therapeutics for treatment of brain injury. This brief review aims to summarize the current state of the science's relevance to neurorehabilitation, and may act as a resource for those seeking to understand the precedence for these ongoing clinical trials.

Methods: Narrative mini-review of studies published related to psychedelic therapeutics and brain injury.

Results: Recent in vitro, in vivo, and case report studies suggest psychedelic pharmacotherapies may influence the future of brain injury treatment through modulation of neuroinflammation, hippocampal neurogenesis, neuroplasticity, and brain complexity.

Conclusions: Historical data on the safety of some of these substances could serve in effect as phase 0 and phase I studies. Further phase II trials will illuminate how these drugs may treat brain injury, particularly TBI and reperfusion injury from stroke.

Tetrahydrocannabinol and cannabidiol as an oromucosal spray in a 1:1 ratio: a therapeutic option for patients with central post-stroke pain syndrome?

Central pain after stroke due to brainstem infarction is very rare. Treatment is difficult and specific guidelines are lacking. This is the report of a 61-year-old female patient who, after a posterolateral left medulla oblongata insult with incomplete Wallenberg syndrome, subsequently developed a burning and tingling pain in the contralateral leg and a burning and shooting pain in the ipsilateral face in trigeminal branches 1 and 2. More than 3 years of therapy with amitriptyline, gabapentin, pregabalin and various grade II and III opioids was ineffective or showed intolerable side effects. The administration of tetrahydrocannabinol and cannabidiol as an oromucosal spray in a 1:1 ratio improved the pain situation and quality of life quickly and permanently. The encouraging results in the present case may suggest that treatment with medical cannabis should be considered in similar cases when standard therapies are insufficient.

Characterization of CB2 Receptor Expression in Peripheral Blood Monocytes of Acute Ischemic Stroke Patients

Both preclinical and clinical evidence supports the involvement of the endocannabinoid system in the pathobiology of cerebral ischemia. Selective cannabinoid-2 (CB2) receptor agonists exert significant neuroprotection in animal models of focal brain ischemia through a robust anti-inflammatory effect, involving both resident and peripheral immune cells. Nevertheless, no definitive studies demonstrating the relevance of CB2 receptors in human stroke exist.Using rtPCR and flow cytometry assays, we investigated CB2 receptor expression in circulating monocytes from 26 acute ischemic stroke patients and 16 age-matched healthy controls (CT). We also evaluated miR-665 expression, as potential CB2 receptor regulator. The median mRNA levels of CB2 were significantly (p < 0.0001) increased in total monocytes 24 h and 48 h after stroke as compared with CT. This was paralleled by elevation of miR-665 levels in monocytes collected from patients 24 h (p < 0.05 vs CT) and 48 h (p < 0.05 vs CT and p < 0.0001 vs 24 h) after ischemic stroke. Furthermore, an increased percentage of CB2+/CD16+ events, but not CB2+/CD14+ events, was found 24 h [20.17% (IQR, 17.22-23.58)] and 48 h [18.61% (IQR, 15.44-22.06)] after ischemic stroke when compared with CT [10.96% (IQR, 9.185-13.32)]. The percentage of CB2+/CD16+ events in monocytes was positively correlated with NIHSS score at entrance (r = 0.4327, p = 0.027). The potential beneficial functions of CD16+ intermediate and nonclassical monocytes in stroke and the elevated expression of CB2 receptor in these subsets strongly suggest that CB2 receptor agonists can be exploited for the treatment of ischemic stroke patients.

Targeting the endocannabinoid system: a predictive, preventive, and personalized medicine-directed approach to the management of brain pathologies

Cannabis-inspired medical products are garnering increasing attention from the scientific community, general public, and health policy makers. A plethora of scientific literature demonstrates intricate engagement of the endocannabinoid system with human immunology, psychology, developmental processes, neuronal plasticity, signal transduction, and metabolic regulation. Despite the therapeutic potential, the adverse psychoactive effects and historical stigma, cannabinoids have limited widespread clinical application. Therefore, it is plausible to weigh carefully the beneficial effects of cannabinoids against the potential adverse impacts for every individual. This is where the concept of "personalized medicine" as a promising approach for disease prediction and prevention may take into the account. The goal of this review is to provide an outline of the endocannabinoid system, including endocannabinoid metabolizing pathways, and will progress to a more in-depth discussion of the therapeutic interventions by endocannabinoids in various neurological disorders.

Cannabis use and outcomes after aneurysmal subarachnoid hemorrhage: A nationwide retrospective cohort study

BACKGROUND

Cannabis is the most consumed recreational drug in the world. It is possible that cannabis has an association with an increased risk of vasospasm-related strokes and delayed cerebral ischemia (DCI), which are major causes of morbidity and mortality in aneurysmal subarachnoid hemorrhage (aSAH). Hence, this study aimed to explore the independent relationship between cannabis use and outcomes after aSAH using the 2016 United States Nationwide Inpatient Sample.

METHODS

This study was conducted using the 2016 National Inpatient Sample with ICD-10 codes. Multivariate logistic regression was used to examine the association between cannabis use, the primary (inpatient mortality) and secondary outcomes.

RESULTS

There were 42,394 patients identified with aSAH, of whom 925 were identified as cannabis users. Cannabis users and non-users were similar in terms of severity of aSAH. Although the unadjusted mortality rate was lower among cannabis users (16%) than non-users (22%), (p = 0.04), both the age-adjusted odds ratio (OR) (0.83, 95% confidence interval (CI): 0.56; 1.24) and the multivariate-adjusted OR (0.87, 95% CI: 0.54; 1.42) did not reach statistical significance. Secondary outcomes did not reach statistical significance.

CONCLUSION

In this nationwide cohort, cannabis users with aSAH had similar outcomes compared to nonusers. However, these results are likely limited by underreporting of cannabis use. Future prospective studies are needed to elucidate the pathophysiology and association between cannabis and outcomes following aSAH.

Marijuana Use Among Young Adults (18-44 Years of Age) and Risk of Stroke: A Behavioral Risk Factor Surveillance System Survey Analysis

Background and Purpose- Amidst legalization of therapeutic and recreational use of marijuana/cannabis in the United States, cerebrovascular effects of marijuana use remain largely unknown, especially among young adults. We aimed to examine the association between marijuana use (18-44 years) among young adults and stroke events. Methods- The study analyzed pooled data from the Behavioral Risk Factor Surveillance System (2016-2017)-a nationally representative cross-sectional survey collected by the Centers for Disease Control and Prevention. Weighted logistic regression models were used to examine an association of recent marijuana use (within the last 30 days) and stroke in young adults (18-44 years) adjusting for patient demographics, risk behavior, and relevant comorbidities. Results- Overall, 13.6% of participants (n=43 860; weighted 35.5 million; 49.9% men) reported using marijuana recently (in the last month), with 63.3% of them being men. Compared with nonusers, marijuana users were often younger (18-34 years; 73.8% versus 61%), non-Hispanic white or black, and with some college education. Marijuana users were often physically active (81.8% versus 77.5%), heavy drinkers (16.8% versus 4.9%), current combustible cigarette users (37.9% versus 15%) and had lower prevalence of hypertension, diabetes mellitus, and hyperlipidemia as compared with nonusers (P<0.01). Young adults with recent marijuana use showed 1.82× higher odds (adjusted odds ratio, 1.82 [95% CI, 1.08-3.10]) of stroke compared with nonusers, which further increased to 2.45× higher (adjusted odds ratio, 2.45 [95% CI, 1.31-4.60]) among frequent marijuana users (>10 days/month). Compared with nonusers, stroke odds were even higher among frequent marijuana users with concomitant combustible cigarette use (adjusted odds ratio, 3.12 [95% CI, 1.40-6.97]) and e-cigarette use (adjusted odds ratio, 2.63 [95% CI, 1.07-6.46]), respectively. Conclusions- There may be a significantly higher odds of stroke in young marijuana users (18-44 years) as compared with nonusers with even greater odds among frequent users (>10 days/month).