Myocardial maladaptation to pressure overload in CB2 receptor-deficient mice

The effect of cannabinoid type Ⅱ receptor on the excitability of substantia nigra dopaminergic neurons

The biological effects of cannabinoids are mainly mediated by two members of the G-protein-coupled-receptor family: cannabinoid type 1 receptor (CB1R) and cannabinoid type 2 receptor (CB2R). Unlike CB1R, CB2R is considered a "peripheral" cannabinoid receptor. However, recent studies have found that CB2R is widely expressed in the central nervous system and is involved in dopamine related behavioral regulation, including dietary behavior, weight regulation, anxiety, and schizophrenia like behavior. Our previous laboratory research demonstrated that activating CB2R on dopaminergic neurons in the ventral tegmental area can regulate addictive behavior in animals by inhibiting neuronal excitability. However, it is currently unclear whether CB2R on dopaminergic neurons in the substantia nigra compacta (SNc) has similar therapeutic potential. Brain patch clamp results have shown that the CB2R agonist JWH133 significantly inhibits the discharge of SNc dopamine neurons in a concentration dependent manner. The pharmacological blocker AM630 of CB2R can reverse this inhibitory effect, indicating that the expression of CB2R in SNc dopaminergic neurons is functional. After treatment with JWH133, the number of induced action potentials decreased, and the peak potential interval time, action potential start time, and potential amplitude after hyperpolarization amplitude all increased. In addition, synaptic current results showed that JWH133 can significantly reduce the frequency of miniature excitatory postsynaptic currents, indicating that activating CB2R to some extent inhibits the release of presynaptic glutamate and indirectly excites postsynaptic neurons.

Therapeutic potential of agents targeting cannabinoid type 2 receptors in organ fibrosis

The endocannabinoid system has garnered attention as a potential therapeutic target in a range of pathological disorders. Cannabinoid receptors type 2 (CB2) are a class of G protein-coupled receptors responsible for transmitting intracellular signals triggered by both endogenous and exogenous cannabinoids, including those derived from plants (phytocannabinoids) or manufactured synthetically (synthetic cannabinoids). Recent recognition of the role of CB2 receptors in fibrosis has fueled interest in therapeutic targeting of CB2 receptors in fibrosis. Fibrosis is characterized by the alteration of the typical cellular composition within the tissue parenchyma, resulting from exposure to diverse etiological factors. The pivotal function of CB2 agonists has been widely recognized in the regulation of inflammation, fibrogenesis, and various other biological pathologies. The modulation of CB2 receptors, whether by enhancing their expression or activating their function, has the potential to provide benefits in numerous conditions, particularly by avoiding any associated adverse effects on the central nervous system. The sufficient activation of CB2 receptors resulted in the complete suppression of gene expression related to transforming growth factor β1 and its subsequent fibrogenic response. Multiple reports have also indicated the diverse functions that CB2 agonists possess in mitigating chronic inflammation and subsequent fibrosis development in various types of tissues. While currently in the preclinical stage, the advancement of CB2 compounds has garnered significant attention within the realm of drug discovery. This review presents a comprehensive synthesis of various independent experimental studies elucidating the pivotal role of identified natural and synthetic CB2 agonists in the pathophysiology of organ fibrosis, specifically in the cardiac, hepatic, and renal systems.

Cannabidiol Exposure During Gestation Leads to Adverse Cardiac Outcomes Early in Postnatal Life in Male Rat Offspring

Introduction: Studies indicate that ∼7% of pregnant individuals in North America consume cannabis in pregnancy. Pre-clinical studies have established that maternal exposure to Δ9-tetrahydrocannabinol (THC; major psychoactive component in cannabis) leads to fetal growth restriction and impaired cardiac function in offspring. However, the effects of maternal exposure to cannabidiol (CBD; major non-euphoric constituent) on cardiac outcomes in offspring remain unknown. Therefore, our objective is to investigate the functional and underlying molecular impacts in the hearts of offspring exposed to CBD in pregnancy. Methods: Pregnant Wistar rats were exposed to either 3 or 30 mg/kg CBD or vehicle control i.p. daily from gestational day 6 to term. Echocardiography was used to assess cardiac function in male and female offspring at postnatal day (PND) 21. Furthermore, quantitative polymerase chain reaction (qPCR), immunoblotting, and bulk RNA-sequencing (RNA-seq) were performed on PND21 offspring hearts. Results: Despite no differences in the heart-to-body weight ratio, both doses of CBD led to reduced cardiac function exclusively in male offspring at 3 weeks of age. Underlying this, significant alterations in the expression of the endocannabinoid system (ECS; e.g., decreased cannabinoid receptor 2) were observed. In addition, bulk RNA-seq data demonstrated transcriptional pathways significantly enriched in mitochondrial function/metabolism as well as development. Conclusion: Collectively, we demonstrated for the first time that gestational exposure to CBD, a constituent perceived as safe, leads to early sex-specific postnatal cardiac deficits and alterations in the cardiac ECS in offspring.

Fatty Acid Amide Hydrolase Deficiency Is Associated with Deleterious Cardiac Effects after Myocardial Ischemia and Reperfusion in Mice

Ischemic cardiomyopathy leads to inflammation and left ventricular (LV) dysfunction. Animal studies provided evidence for cardioprotective effects of the endocannabinoid system, including cardiomyocyte adaptation, inflammation, and remodeling. Cannabinoid type-2 receptor (CB2) deficiency led to increased apoptosis and infarctions with worsened LV function in ischemic cardiomyopathy. The aim of our study was to investigate a possible cardioprotective effect of endocannabinoid anandamide (AEA) after ischemia and reperfusion (I/R). Therefore, fatty acid amide hydrolase deficient (FAAH)^−/− mice were subjected to repetitive, daily, 15 min, left anterior descending artery (LAD) occlusion over 3 and 7 consecutive days. Interestingly, FAAH^−/− mice showed stigmata such as enhanced inflammation, cardiomyocyte loss, stronger remodeling, and persistent scar with deteriorated LV function compared to wild-type (WT) littermates. As endocannabinoids also activate PPAR-α (peroxisome proliferator-activated receptor), PPAR-α mediated effects of AEA were eliminated with PPAR-α antagonist GW6471 i.v. in FAAH^−/− mice. LV function was assessed using M-mode echocardiography. Immunohistochemical analysis revealed apoptosis, macrophage accumulation, collagen deposition, and remodeling. Hypertrophy was determined by cardiomyocyte area and heart weight/tibia length. Molecular analyses involved Taqman^® RT-qPCR and immune cells were analyzed with fluorescence-activated cell sorting (FACS). Most importantly, collagen deposition was reduced to WT levels when FAAH^−/− mice were treated with GW6471. Chemokine ligand-2 (CCL2) expression was significantly higher in FAAH^−/− mice compared to WT, followed by higher macrophage infiltration in infarcted areas, both being reversed by GW6471 treatment. Besides restoring antioxidative properties and contractile elements, PPAR-α antagonism also reversed hypertrophy and remodeling in FAAH^−/− mice. Finally, FAAH^−/−-mice showed more substantial downregulation of PPAR-α compared to WT, suggesting a compensatory mechanism as endocannabinoids are also ligands for PPAR-α, and its activation causes lipotoxicity leading to cardiomyocyte apoptosis. Our study gives novel insights into the role of endocannabinoids acting via PPAR-α. We hypothesize that the increase in endocannabinoids may have partially detrimental effects on cardiomyocyte survival due to PPAR-α activation.

Activation of cannabinoid receptor 2 attenuates Angiotensin II-induced atrial fibrillation via a potential NOX/CaMKII mechanism

Background

Atrial fibrillation (AF) is the most frequent arrythmia managed in clinical practice. Several mechanisms have been proposed to contribute to the occurrence and persistence of AF, in which oxidative stress plays a non-negligible role. The endocannabinoid system (ECS) is involved in a variety physiological and pathological processes. Cannabinoid receptor 1 (CB1R) and cannabinoid receptor 2 (CB2R) are expressed in the heart, and studies have shown that activating CB2R has a protective effect on the myocardium. However, the role of CB2R in AF is unknown.

Materials and methods

Angiotensin II (Ang II)-infused mice were treated with the CB2R agonist AM1241 intraperitoneally for 21 days. Atrial structural remodeling, AF inducibility, electrical transmission, oxidative stress and fibrosis were measured in mice.

Results

The susceptibility to AF and the level of oxidative stress were increased significantly in Ang II-infused mice. In addition, nicotinamide adenine dinucleotide phosphate oxidase 2 (NOX2), NOX4, and oxidized Ca²⁺/calmodulin-dependent protein kinase II (ox-CaMKII) were highly expressed. More importantly, treatment with AM1241 activated CB2R, resulting in a protective effect.

Conclusion

The present study demonstrates that pharmacological activation of CB2R exerts a protective effect against AF via a potential NOX/CaMKII mechanism. CB2R is a potential therapeutic target for AF.

Understanding the role of alternative macrophage phenotypes in human atherosclerosis

INTRODUCTION

Atherosclerosis-based ischemic heart disease is still the primary cause of death throughout the world. Over the past decades there has been no significant changes in the therapeutic approaches to atherosclerosis, which are mainly based on lipid lowering therapies and management of comorbid conditions such as diabetes and hypertension. The involvement of macrophages in atherosclerosis has been recognized for decades. More recently, a more detailed and sophisticated understanding of their various phenotypes and roles in the atherosclerotic process has been recognized. This new data is revealing how specific subtypes of macrophage-induced inflammation may have distinct effects on atherosclerosis progression and may provide new approaches for treatment, based upon targeting of specific macrophage subtypes.

AREAS COVERED

We will comprehensively review the spectrum of macrophage phenotypes and how they contribute to atherosclerotic plaque development and progression.

EXPERT OPINION

Various signals derived from atherosclerotic lesions drive macrophages into complex subsets with different gene expression profiles, phenotypes, and functions, not all of which are understood. Macrophage phenotypes include those that enhance, heal, and regress the atherosclerotic lesions though various mechanisms. Targeting of specific macrophage phenotypes may provide a promising and novel approach to prevent atherosclerosis progression.

Role of cannabinoids and the endocannabinoid system in modulation of diabetic cardiomyopathy

Diabetic complications, chiefly seen in long-term situations, are persistently deleterious to a large extent, requiring multi-factorial risk reduction strategies beyond glycemic control. Diabetic cardiomyopathy is one of the most common deleterious diabetic complications, being the leading cause of mortality among diabetic patients. The mechanisms of diabetic cardiomyopathy are multi-factorial, involving increased oxidative stress, accumulation of advanced glycation end products (AGEs), activation of various pro-inflammatory and cell death signaling pathways, and changes in the composition of extracellular matrix with enhanced cardiac fibrosis. The novel lipid signaling system, the endocannabinoid system, has been implicated in the pathogenesis of diabetes and its complications through its two main receptors: Cannabinoid receptor type 1 and cannabinoid receptor type 2, alongside other components. However, the role of the endocannabinoid system in diabetic cardiomyopathy has not been fully investigated. This review aims to elucidate the possible mechanisms through which cannabinoids and the endocannabinoid system could interact with the pathogenesis and the development of diabetic cardiomyopathy. These mechanisms include oxidative/ nitrative stress, inflammation, accumulation of AGEs, cardiac remodeling, and autophagy. A better understanding of the role of cannabinoids and the endocannabinoid system in diabetic cardiomyopathy may provide novel strategies to manipulate such a serious diabetic complication.

Genetic deletion of the cannabinoid receptors CB1 and CB2 enhances inflammation with diverging effects on skin wound healing in mice

AIMS

Inflammation during wound healing is both essential and critical for restoring tissue integrity. Participating cells secrete soluble factors to regulate the inflammatory phase and to induce the adjacent regenerative processes. If pro-inflammatory signals are overexpressed, the wound stagnates in the inflammatory phase, which decelerates regular wound healing. The endocannabinoid system is ascribed great significance in maintenance of tissue homeostasis. It mediates several effects through the cannabinoid receptors CB1 and CB2.

MAIN METHODS

In order to clarify the role of these receptors in wound healing, excisional wounds were created on wildtype and CB1 and CB2 knockout mice. The wound closure was analyzed over a period of 14 days, and cytokine concentrations of tissue homogenisates were measured by ELISA. MSCs were isolated from the animals' subcutaneous adipose tissue and analyzed for viability and differentiation capacity, in vitro.

KEY FINDINGS

Deletion of CB2 increased Interleukin (IL)-6 and tumor necrosis factor (TNF)-α but did not affect tissue regeneration. In CB1-deficient animals, wound closure was delayed during early phases of healing, which was accompanied by increased concentrations of monocyte chemoattractant protein (MCP)-1 and TNF-α. CB1 and CB2 knockout MSCs presented altered viability and differentiation capacity compared to wildtype MSCs. The CB1-deficient MSCs released high levels of MCP-1 upon stimulation with TNF-α and IL-1β.

SIGNIFICANCE

The data indicate that both cannabinoid receptors regulate inflammation, and this study emphasizes the important role of CB1 in wound repair. Furthermore, our findings suggest that the secretome of CB1-deficient MSCs may contribute to the wound healing delay, in vivo.

AM1241 alleviates myocardial ischemia-reperfusion injury in rats by enhancing Pink1/Parkin-mediated autophagy

AIMS

The purpose of this study was to reveal the therapeutic efficacy and underlying mechanism of cannabinoid type 2 receptor agonist (AM1241) on myocardial ischemia-reperfusion injury (MIRI) in rats.

MAIN METHODS

We established a rat myocardial ischemia/reperfusion (I/R) model and H9c2 hypoxia/reoxygenation (H/R) model. ELISA was used to determine the concentrations of cardiac troponin I (cTnI), creatine kinase-MB (CK-MB), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) in plasma. EB/TTC staining was performed to observe the myocardial infarct size. Besides, the pathological changes of myocardial tissue were identified via H&E staining and Masson's trichrome staining. TUNEL assay was performed to examine myocardial apoptosis. Then, the protein expression of Pink1, Parkin and autophagy-related markers (Beclin-1, P62 and LC3) were detected by Western blot, and autophagy was evaluated by Mitotracker staining.

KEY FINDINGS

The results of EB/TTC staining, H&E staining, Masson's trichrome staining and cardiac enzymes measuring showed that AM1241 treatment significantly diminished infarct size, the structural abnormalities and the activities of cardiac enzymes (cTnI, CK-MB, AST and LDH). AM1241 also significantly reduced the number of TUNEL-positive cells induced by I/R in a dose-dependent manner. Furthermore, AM1241 activated Pink1/Parkin signaling pathway and upregulated autophagy level.

SIGNIFICANCE

AM1241 exerts a protective effect against MIRI in rats by inducing autophagy through the activation of Pink1/Parkin pathway.

CX3CR1 is a prerequisite for the development of cardiac hypertrophy and left ventricular dysfunction in mice upon transverse aortic constriction

The CX3CL1/CX3CR1 axis mediates recruitment and extravasation of CX3CR1-expressing subsets of leukocytes and plays a pivotal role in the inflammation-driven pathology of cardiovascular disease. The cardiac immune response differs depending on the underlying causes. This suggests that for the development of successful immunomodulatory therapy in heart failure due to chronic pressure overload induced left ventricular (LV) hypertrophy, the underlying immune patterns must be examined. Here, the authors demonstrate that Fraktalkine-receptor CX3CR1 is a prerequisite for the development of cardiac hypertrophy and left ventricular dysfunction in a mouse model of transverse aortic constriction (TAC). The comparison of C57BL/6 mice with CX3CR1 deficient mice displayed reduced LV hypertrophy and preserved cardiac function in response to pressure overload in mice lacking CX3CR1. Moreover, the normal immune response following TAC induced pressure overload which is dominated by Ly6C^low macrophages changed to an early pro-inflammatory immune response driven by neutrophils, Ly6C^high macrophages and altered cytokine expression pattern in CX3CR1 deficient mice. In this early inflammatory phase of LV hypertrophy Ly6C^high monocytes infiltrated the heart in response to a C-C chemokine ligand 2 burst. CX3CR1 expression impacts the immune response in the development of LV hypertrophy and its absence has clear cardioprotective effects. Hence, suppression of CX3CR1 may be an important immunomodulatory therapeutic target to ameliorate pressure-overload induced heart failure.

Pharmacological activation of CB2 receptor protects against ethanol-induced myocardial injury related to RIP1/RIP3/MLKL-mediated necroptosis

Chronic ethanol abuse can lead to harmful consequences for the heart, resulting in systolic dysfunction, variability in the heart rate, arrhythmia, and cardiac remodelling. However, the precise molecular mechanism responsible for ethanol-induced cardiomyopathy is poorly understood. In this regard, the present study aimed to describe the RIP1/RIP3/MLKL-mediated necroptotic cell death that may be involved in ethanol-induced cardiomyopathy and characterize CBR-mediated effects on the signalling pathway and myocardial injury. We performed an ethanol vapour administration experiment to analyse the effects of ethanol on cardiac structure and function in male C57BL/6J mice. Ethanol induced a significant decline in the cardiac structure and function, as evidenced by a decline in ejection fraction and fractional shortening, and an increase in serum Creatine Kinase levels, myocardial collagen content, and inflammatory reaction. Furthermore, ethanol also upregulated the expression levels of necroptosis-related markers such as p-RIP1, p-RIP3, and p-MLKL in the myocardium. Nec-1 treatment exerted significant cardioprotective effects by salvaging the heart tissue, improving the cardiac function, and mitigating inflammation and necroptosis. In addition, ethanol abuse caused an imbalance in the endocannabinoid system and regulated two cannabinoid receptors (CB1R and CB2R) in the myocardium. Treatment with selective CB2R agonists, JWH-133 or AM1241, markedly improved the cardiac dysfunction and reduced the ethanol-induced necroptosis in the myocardium. Altogether, our data provide evidence that ethanol abuse-induced cardiotoxicity can possibly be attributed to the RIP1/RIP3/MLKL-mediated necroptosis. Moreover, pharmacological activation of CB2R may represent a new cardioprotective strategy against ethanol-induced cardiotoxicity.

Cannabinoids in Metabolic Syndrome and Cardiac Fibrosis

PURPOSE OF REVIEW

This article provides a concise overview of how cannabinoids and the endocannabinoid system (ECS) have significant implications for the prevention and treatment of metabolic syndrome (MetS) and for the treatment of cardiovascular disorders, including cardiac fibrosis.

RECENT FINDINGS

Over the past few years, the ECS has emerged as a pivotal component of the homeostatic mechanisms for the regulation of many bodily functions, including inflammation, digestion, and energy metabolism. Therefore, the pharmacological modulation of the ECS by cannabinoids represents a novel strategy for the management of many diseases. Specifically, increasing evidence from preclinical research studies has opened new avenues for the development of cannabinoid-based therapies for the management and potential treatment of MetS and cardiovascular diseases. Current information indicates that modulation of the ECS can help maintain overall health and well-being due to its homeostatic function. From a therapeutic perspective, cannabinoids and the ECS have also been shown to play a key role in modulating pathophysiological states such as inflammatory, neurodegenerative, gastrointestinal, metabolic, and cardiovascular diseases, as well as cancer and pain. Thus, targeting and modulating the ECS with cannabinoids or cannabinoid derivatives may represent a major disease-modifying medical advancement to achieve successful treatment for MetS and certain cardiovascular diseases.

CpG postconditioning after reperfused myocardial infarction is associated with modulated inflammation, less apoptosis, and better left ventricular function

Postconditioning attenuates inflammation and fibrosis in myocardial infarction (MI). The aim of this study was to investigate whether postconditioning with the cytosine-phosphate-guanine (CpG)-containing Toll-like receptor-9 (TLR9) ligand 1668-thioate (CpG) can modulate inflammation and remodeling in reperfused murine MI. Thirty minutes of left descending coronary artery (LAD) occlusion was conducted in 12-wk-old C57BL/6 mice. Mice were treated with CpG intraperitoneally 5 min before reperfusion. The control group received PBS; the sham group did not undergo ischemia. M-mode echocardiography (3, 7, and 28 days) and Millar left ventricular (LV) catheterization were performed (7 and 28 days) before the hearts were excised and harvested for immunohistochemical (6 h, 24 h, 3 days, 7 days, and 28 days), gene expression (6 h, 24 h, and 3 days; Taqman RT-qPCR), protein, and FACS analysis (24 h and 3 days). Mice treated with CpG showed significantly better LV function after 7 and 28 days of reperfusion. Protein and mRNA expressions of proinflammatory and anti-inflammatory cytokines were significantly induced after CpG treatment. Histology revealed fewer macrophages in CpG mice after 24 h, confirmed by FACS analysis with a decrease in both classically M1- and alternative M2a-monocytes. CpG treatment reduced apoptosis and cardiomyocyte loss and was associated with induction of adaptive mechanisms, e.g., of heme-oxigenase-1 and β-/α-myosin heavy chain (MHC) ratio. Profibrotic markers collagen type Iα (Col-Ια) and Col-III induction was abrogated in CpG mice, accompanied by fewer myofibroblasts. This led to the formation of a smaller scar. Differential matrix metalloproteinase (MMP)/tissue inhibitor of metalloproteinase (TIMP) expression contributed to attenuated remodeling in CpG, resulting in preserved cardiac function in a Toll-like receptor 1- and TLR9-dependent manner. Our study suggests a cardioprotective mechanism of CpG postconditioning, involving Toll-like receptor-driven modulation of inflammation. This is followed by attenuated remodeling and preserved LV function.NEW & NOTEWORTHY Cytosine-phosphate-guanine (CpG) postconditioning seems to mediate inflammation via Toll-like receptor-1 and Toll-like receptor-9 signaling. Enhanced cytokine and chemokine expressions are partly attenuated by IL-10 and matrix metalloproteinase-8 (MMP8) induction, being associated with lower macrophage infiltration and M1-monocyte differentiation. Furthermore, switch from α- to β-MHC and balanced MMP/TIMP expression led to lesser cardiomyocyte apoptosis, smaller scar size, and preserved cardiac function. Data of pharmacological postconditioning have been widely disappointing to date. Our study suggests a new pathway promoting myocardial postconditioning via Toll-like receptor activation.

A Guide to Targeting the Endocannabinoid System in Drug Design

The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.

Macrophages: First guards in the prevention of cardiovascular diseases

Cardiovascular diseases (CVD) remain one of the leading causes of mortality worldwide, especially in developing countries. It is widely known that severe inflammation can lead to atherosclerosis, which can cause various downstream pathologies, including myocardial injury and viral myocarditis. To date, several strategies have been proposed to prevent and cure CVD. The use of targeting macrophages has emerged as one of the most effective therapeutic approaches. Macrophages play a crucial role in eliminating senescent and dead cells while maintaining myocardial electrical activity and repairing myocardial injury. They also contribute to tissue repair and remodeling and plaque stabilization. Targeting macrophage pathways can, therefore, be advantageous in CVD care since it can lead to decreased aggregation of mononuclear cells at the injured site in the heart. Furthermore, it inhibits the development of pro-inflammatory factors, facilitates cholesterol outflow, and reduces the lipid concentration. More in-depth studies are still needed to formulate a comprehensive classification of phenotypes for different macrophages and determine their roles in the pathogenesis of CVD. In this review, we summarize the recent advances in the understanding of the role of macrophages in the prevention and cure of CVD.

Endocannabinoid system and cardiometabolic risk factors: A comprehensive systematic review insight into the mechanistic effects of omega-3 fatty acids

Increased levels of endocannabinoids, 2-arachidonoylglycerol (2-AG) and arachidonoyl ethanolamide (AEA) have a pathophysiological role in the setting of cardiometabolic diseases. This systematic review was carried out to appraise the effect of omega-3 on cardiometabolic risk factors by highlighting the mediating effect of endocannabinoids. SCOPUS, PubMed, Embase, Google Scholar and ProQuest databases were searched until January 2020. All published English-language animal studies and clinical trials that evaluated the effects of omega-3 on cardiometabolic diseases with a focus on endocannabinoids were included. Of 1407 studies, 16 animal studies and three clinical trials were included for analysis. Eleven animal studies and two human studies showed a marked reduction in 2-AG and AEA levels following intake of omega-3 which correlated with decreased adiposity, weight gain and improved glucose homeostasis. Moreover, endocannabinoids were elevated in three studies that replaced omega-3 with omega-6. Omega-3 showed anti-inflammatory properties due to reduced levels of inflammatory cytokines, regulation of T-cells function and increased levels of eicosapentaenoyl ethanolamide, docosahexaenoyl ethanolamide and oxylipins; however, a limited number of studies examined a correlation between inflammatory cytokines and endocannabinoids following omega-3 administration. In conclusion, omega-3 modulates endocannabinoid tone, which subsequently attenuates inflammation and cardiometabolic risk factors. However, further randomized clinical trials are needed before any recommendations are made to target the ECS using omega-3 as an alternative therapy to drugs for cardiometabolic disease improvement.

Chronic Cannabidiol Administration Fails to Diminish Blood Pressure in Rats with Primary and Secondary Hypertension Despite Its Effects on Cardiac and Plasma Endocannabinoid System, Oxidative Stress and Lipid Metabolism

We investigated the influence of cannabidiol (CBD) on blood pressure (BP) and heart rate (HR) in spontaneously (SHR) and deoxycorticosterone (DOCA-salt) hypertensive rats. Hypertension was connected with increases in cardiac and plasma markers of lipid peroxidation in both models, whereas cardiac endocannabinoid levels decreased in SHR and increased in DOCA-salt. CBD (10 mg/kg once a day for 2 weeks) did not modify BP and HR in hypertension but counteracted pro-oxidant effects. Moreover, it decreased cardiac or plasma levels of anandamide, 2-arachidonoylglycerol and oleoyl ethanolamide in DOCA-salt and inhibited the activity of fatty acid amide hydrolase (FAAH) in both models. In the respective normotensive control rats, CBD increased lipid peroxidation, free fatty acid levels and FAAH activity. In conclusion, chronic CBD administration does not possess antihypertensive activity in a model of primary and secondary (DOCA-salt) hypertension, despite its antioxidant effect. The latter may be direct rather than based on the endocannabinoid system. The unexpected CBD-related increase in lipid peroxidation in normotensive controls may lead to untoward effects; thus, caution should be kept if CBD is used therapeutically.