Category Archives: Hypertension (High blood pressure)

The endocannabinoid system in cardiovascular function: novel insights and clinical implications.

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Clinical Autonomic Research

“Cardiovascular disease is now recognized as the number one cause of death in the world, and the size of the population at risk continues to increase rapidly. The dysregulation of the endocannabinoid (eCB) system plays a central role in a wide variety of conditions including cardiovascular disorders. Cannabinoid receptors, their endogenous ligands, as well as enzymes conferring their synthesis and degradation, exhibit overlapping distributions in the cardiovascular system. Furthermore, the pharmacological manipulation of the eCB system has effects on blood pressure, cardiac contractility, and endothelial vasomotor control. Growing evidence from animal studies supports the significance of the eCB system in cardiovascular disorders.

RESULTS:

Drugs targeting CB1R, CB2R, TRPV1 and PPARs are proven effective in animal models mimicking cardiovascular disorders such as hypertension, atherosclerosis and myocardial infarction. Despite the setback of two clinical trials that exhibited unexpected harmful side-effects, preclinical studies are accelerating the development of more selective drugs with promising results devoid of adverse effects.

CONCLUSION:

Over the last years, increasing evidence from basic and clinical research supports the role of the eCB system in cardiovascular function. Whereas new discoveries are paving the way for the identification of novel drugs and therapeutic targets, the close cooperation of researchers, clinicians and pharmaceutical companies is needed to achieve successful outcomes.”

https://www.ncbi.nlm.nih.gov/pubmed/29222605

https://link.springer.com/article/10.1007%2Fs10286-017-0488-5

ACPA and JWH-133 modulate the vascular tone of superior mesenteric arteries through cannabinoid receptors, BKCa channels, and nitric oxide dependent mechanisms.

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Pharmacological Reports

“Some cannabinoids, a family of compounds derived from Cannabis sativa (marijuana), have previously shown vasodilator effects in several studies, a feature that makes them suitable for the generation of a potential treatment for hypertension.

The mechanism underlying this vasodilator effect in arteries is still controversial. In this report, we explored how the synthetic cannabinoids ACPA (CB1-selective agonist) and JWH-133 (CB2-selective agonist) regulate the vascular tone of rat superior mesenteric arteries.

CB1 and CB2 receptor activation in superior mesenteric artery causes vasorelaxation by mechanisms involving BKCachannels and NO release.”

https://www.ncbi.nlm.nih.gov/pubmed/29128791

http://www.sciencedirect.com/science/article/pii/S1734114017300361?via%3Dihub

New ACE inhibitory peptides from hemp seed (Cannabis sativa L.) proteins.

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Journal of Agricultural and Food Chemistry

“An hemp seed protein isolate, prepared from defatted hemp seed meals by alkaline solubilization/acid precipitation, was subjected to extensive chemical hydrolysis under acid conditions (6 M HCl). The resulting hydrolysate was fractionated by semipreparative RP-HPLC and the purified fractions were tested as inhibitors of angiotensin converting enzyme (ACE). Mono- and bi-dimensional NMR experiments and LC-MS/MS analyses led to the identification of four potentially bioactive peptides, i.e. GVLY, IEE, LGV, and RVR. They were prepared by solid-phase synthesis, and tested for ACE-inhibitory activity. The IC50 values were GVLY 16 ± 1.5 µM, LGV 145 ± 13 µM, and RVR 526 ± 33 µM, confirming that hemp seed may be a valuable source of hypotensive peptides.”

 https://www.ncbi.nlm.nih.gov/pubmed/29112398
http://pubs.acs.org/doi/abs/10.1021/acs.jafc.7b04522

A single dose of cannabidiol reduces blood pressure in healthy volunteers in a randomized crossover study.

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“Cannabidiol (CBD) is a nonpsychoactive phytocannabinoid used in multiple sclerosis and intractable epilepsies. Preclinical studies show CBD has numerous cardiovascular benefits, including a reduced blood pressure (BP) response to stress. The aim of this study was to investigate if CBD reduces BP in humans.

CONCLUSIONS:

This data shows that acute administration of CBD reduces resting BP and the BP increase to stress in humans, associated with increased HR. These hemodynamic changes should be considered for people taking CBD. Further research is required to establish whether CBD has a role in the treatment of cardiovascular disorders.”

https://www.ncbi.nlm.nih.gov/pubmed/28614793

“Our data show that a single dose of CBD reduces resting blood pressure and the blood pressure response to stress. This may reflect the anxiolytic and analgesic effects of CBD, as well as any potential direct cardiovascular effects. CBD has multiple desirable effects on the cardiovascular system” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5470879/

https://insight.jci.org/articles/view/93760

A Systematic Review and Meta-Analysis of the Haemodynamic Effects of Cannabidiol

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“Cannabidiol (CBD) is the second most abundant phytocannabinoid, after Δ9-tetrahydrocannabinol (THC) and was first isolated from the cannabis extract in 1940.

Given the increasing clinical use of CBD, and the numerous effects of CBD in the cardiovascular system, the aim of the present study was to systematically review and analyse in vivo studies evaluating the effects of CBD on alterations in haemodynamics.

From the limited data available, we conclude that acute and chronic administration of CBD had no effect on BP or HR under control conditions, but reduces BP and HR in stressful conditions, and increases cerebral blood flow (CBF) in mouse models of stroke.

This meta-analysis and systematic review has highlighted the haemodynamic effects of CBD administration in vivo.

The positive effects induced by CBD include maintaining the fall in BP after global hypoxia, reducing the increase in MBP and HR post-stress, and increasing BF in ischaemia-reperfusion models.

It is possible that beneficial effects of CBD on haemodynamics occurs when the cardiovascular system is abnormally altered, suggesting that CBD may be used as a treatment for various cardiovascular disorders, such as hypertension, myocardial infarction and stroke.”

http://journal.frontiersin.org/article/10.3389/fphar.2017.00081/full

Diuretic effects of cannabinoid agonists in mice

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“Cannabinoids both increase urine output and decrease urinary frequency in human subjects. However, these effects have not been systematically evaluated in intact mice, a species commonly used to evaluate the effects of novel cannabinoids.

The present studies investigated whether cannabinoid agonists reliably produce diuresis in mice at doses comparable to those that produce other cannabinoid effects and, further, identified the receptors that may mediate these effects.

These findings suggest that mice may provide a model for understanding the mixed effects of marijuana on urine output, as described in clinical studies, and aid in the development of targeted cannabinoid based therapies for bladder dysfunction.

Clinical studies have reported beneficial effects of smoked or aerosolized cannabis on bladder dysfunction in patients with multiple sclerosis, primarily by decreasing urinary frequency in these subjects following marijuana use. These reports contrast with the earlier clinical reports demonstrating increase in urine output after cannabis administration.

Our findings in mice demonstrate a dose related increase or decrease in urine output, providing a platform for understanding the mixed effects on urine output observed with marijuana in various clinical studies. As noted earlier in a study with rats, the diuresis induced by THC in mice also is weakly naturetic compared to furosemide and further investigations in this area may yield a new, clinically beneficial diuretic.

In contrast, our data suggest that development of peripherally selective cannabinoid CB1 agonists may be beneficial for patients suffering from bladder dysfunction.”

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3872476/

Diuretic effects of cannabinoids.

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“These data indicate that cannabinoids have robust diuretic effects in rats that are mediated via CB1 receptor mechanisms.

Overall, our data indicate that diuresis is a CB1-mediated effect that may serve as a reliable and objective physiologic measure of cannabinoid action in rats; the circumstances under which these results represent a potential therapeutic benefit or potential liability of cannabinoids remain to be determined.

The implications of these findings currently are poorly understood, although a better understanding of mechanisms and sites of action by which cannabinoids increase urine loss may lead to the rational development of novel cannabinergic medications.”  https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3533417/

“Diuretics are medicines that help reduce the amount of water in the body. Diuretics are used to treat the buildup of excess fluid in the body that occurs with some medical conditions such ascongestive heart failure, liver disease, and kidney disease. Some diuretics are also prescribed to treat high bloodpressure. These drugs act on the kidneys to increase urine output. This reduces the amount of fluid in the bloodstream,which in turn lowers blood pressure.” http://medical-dictionary.thefreedictionary.com/diuretics

The endogenous lipid N-arachidonoyl glycine is hypotensive and nitric oxide-cGMP-dependent vasorelaxant.

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“N-arachidonoyl glycine (NAGLY), is the endogenous lipid that activates the G protein-couple receptor 18 (GPR18) with vasodilatory activity in resistance arteries. This study investigates its hemodynamic effects and mechanisms of vasorelaxation.

NAGLY is an endothelium-dependent vasodilator and hypotensive lipid. The vasorelaxation is predominantly via activation of nitric oxide-cGMP pathway and NCX and probably mediated by the “endothelial anandamide” receptor, while the hypotensive effect of NAGLY appears not to involve the anandamide receptor. NAGLY also potentiates carbachol-induced vasorelaxation, the mechanism of which might involve stimulation of NO release.”

https://www.ncbi.nlm.nih.gov/pubmed/27890711

Overactivation of cannabinoid receptor type 1 in rostral ventrolateral medulla promotes cardiovascular responses in spontaneously hypertensive rats.

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“Stimulation of cannabinoid type 1 (CB1) receptor in the rostral ventrolateral medulla (RVLM) increases renal sympathetic nerve activity (RSNA) and blood pressure (BP) in rats.

Thus, we hypothesized that abnormal expression of CB1 receptor in the RVLM may play a critical role in the pathogenesis of essential hypertension.

Taken together, our results suggested that alterations of CB1 receptor desensitization in the RVLM may play a role in the pathogenesis of essential hypertension.”

https://www.ncbi.nlm.nih.gov/pubmed/27861247

The Effect of Chronic Activation of the Novel Endocannabinoid Receptor GPR18 on Myocardial Function and Blood Pressure in Conscious Rats.

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“While acute activation of the novel endocannabinoid receptor GPR18 causes hypotension, there are no reports on GPR18 expression in the heart or its chronic modulation of cardiovascular function. In this study, after demonstrating GPR18 expression in the heart, we show that chronic (2 weeks) GPR18 activation with its agonist abnormal cannabidiol (abn-cbd; 100 µg/kg/day; i.p) produced hypotension, suppressed the cardiac sympathetic dominance, and improved left ventricular (LV) function (increased the contractility index dp/dtmax, and reduced LV end diastolic pressure, LVEDP) in conscious rats. Ex vivo studies revealed increased: (i) cardiac and plasma adiponectin (ADN) levels; (ii) vascular (aortic) endothelial nitric oxide synthase (eNOS) expression, (iii) vascular and serum nitric oxide (NO) levels; (iv) myocardial and plasma cyclic guanosine monophosphate (cGMP) levels; (v) phosphorylation of myocardial protein kinase B (Akt) and extracellular signal regulated kinase 1/2 (ERK1/2) along with reduced myocardial reactive oxygen species (ROS) in abn-cbd treated rats. These biochemical responses contributed to the hemodynamic responses and were GPR18-mediated because concurrent treatment with the competitive GPR18 antagonist (O-1918) abrogated the abn-cbd evoked hemodynamic and biochemical responses. The current findings present new evidence for a salutary cardiovascular role for GPR18, mediated, at least partly, via elevation in the levels of ADN.”

 https://www.ncbi.nlm.nih.gov/pubmed/27676325