In the past, atherosclerosis was largely defined in terms of the accumulation of plaque or bad cholesterol (LDL) within the arterial walls, leading to obstructions. However, it is no understood to be more than a simple build-up of plaque. This obstruction is actually a physical response to injuries in the arterial wall’s lining. Causes of arterial wall injuries include high blood pressure, infectious microbes, or excessive presence of a certain amino acid called homocysteine. Studies have demonstrated that inflammatory molecules stimulate events leading to the development of atherosclerotic lesions. Some researchers consider atherosclerosis a natural type of band-aid approach to cover an injury or inflammation. When the band-aid becomes too thick or breaks loose, symptoms of a chronic or acute nature occur. In mild cases, this can lead to diminished oxygen supply to the tissue on the other side of the occlusion; in acute cases, it can cause severe strokes or heart attacks.
Atherosclerosis develops slowly over many years. If present in the limbs (called peripheral artery disease), it may present as a pain in the legs or arms, especially when exercising. Atherosclerosis in arteries in the torso may produce signs and symptoms similar to heart disease or strokes: primarily chest pains, shortness of breath, or loss of sensation and function (speech and movement of limbs).
Cannabinoids and Atherosclerosis
The discovery of endocannabinoids and their functional roles in the brain and other parts of the body has had tremendous implications in medical science. Cannabinoids receptors are widely present all over the cardiovascular system and that’s the reason researchers believe the endocannabinoid system might play a key role in the regulation of blood circulation and cardiac functions.
Expression of CB2 receptors in the cardiovascular system, such as myocardial cells, blood vessels, and smooth muscle cells, are now confirmed. Studies have reported variations in the expression of CB2 receptors in carotid artery plaques among stroke and asymptomatic patients. Therefore, CB2 receptor expression and signaling appear to be a protective response against acute and chronic pathological events. Additionally, the protective role of CB2 receptors has been documented in various events of atherosclerosis, including restenosis, myocardial ischemia, and cerebral ischemia or reperfusion injury.
Studies are now focusing on biologically active molecules that influence the cannabinoid system, particularly phytocannabinoids. These studies preferentially employed cannabidiol (CBD) as it lacks psychoactive effects. Due to ongoing research studies, the therapeutic role of cannabinoids in the treatment of cardiovascular diseases, including atherosclerosis, is now recognized.
Being well aware that elevated levels of cholesterol, particularly low-density lipoproteins, are the major risk factor for the onset of heart disease and stroke. Due to various biochemical changes and exposure to reactive oxygen species (ROS), or free radicals, the LDLD gets oxidized into Ox-LDL that accumulates progressively in the interior layer of the arteries. These modified lipoproteins attract immune molecules (macrophages) and trigger inflammation and immune reaction (apoptosis) within the atherosclerotic plaques (foam cells).
In advanced stages, the inflammatory immune reaction against atherosclerotic plaques ends up in the plaque rupture. This is followed by damage to the interior layers of the blood supplying arteries, as well as plaque instability. These events trigger pro-atherogenic risks and also contribute to blood coagulation that impairs the blood supply to the brain and heart and can cause a stroke.
The role of endocannabinoids and cannabinoid receptors are now evident. Altogether, we can assume that modulation of these receptors may have therapeutic implications for atherosclerosis.
Naturally, cannabinoids are immunomodulators with significant anti-inflammatory properties. As atherosclerosis is an inflammatory disease, cannabinoids could counter the progression of the disease as well as prevent the onset by blunting the inflammation.
CB1 receptors are not only found in the brain but are also present in immune cells – at relatively lower levels. Endocannabinoids can regulate the immune system by inhibiting certain enzymes that are involved in the regulation of inflammatory reactions. Activation of endocannabinoids could treat immune-related injury to these vital organs. Based on research studies, it has now been confirmed that cannabinoids can be helpful in treating inflammatory diseases, including atherosclerosis, by suppressing T-cells and other immune components. The evidence is also irrefutable that cannabis can be protective against inflammation associated with ischemic-reperfusion injury, a common problem that occurs after stroke or atherosclerosis. In another study, it has been concluded that low dose oral THC has decreased inflammatory response in atherosclerotic plaques. This study clearly demonstrated the presence of CB2-receptors in the inflammatory cells, atherosclerotic plaques, and the target organs.
By considering low doses of THC, the psychoactive effects can be avoided. We are now able to see that both CBD and THC could be helpful from the early stages of atherosclerosis. These benefits are particularly desirable for those who want to prevent atherosclerosis onset. There is a downside, though, and this is vitally important to consider while research is ongoing:
THC in higher doses, is not for everyone.
A number of studies have warned about the increased risk of angina and coronary problems among cannabis users who ingest large doses of THC. Most experts believe that cannabis side-effects are attributed to whole cannabis smoking, but are not related to other routes of administration, or with CBD. Reliable research studies have warned that THC-mediated CB1 receptor modulation can be adverse for cardiac patients. Although CB1 and CB2 receptors are widely distributed in the cardiovascular system, as well as in pathological plaques, activation of these receptors may also contribute to the worsening on atherosclerosis. Recent studies have concluded that the negative effects of cannabis are linked with CB1 receptor activation, hence THC is not suitable as an atherosclerosis treatment.
And here is why:
THC activates brain localized CB1 receptors that lead to increased blood pressure and pulse rate. Their factors increase angina risk and pose as a risk factor for stroke and heart attack. Additionally, smoking cannabis may also impair blood oxygen supply to the heart and the brain by increasing carboxyhemoglobin formation. This may just be the reason why some people who smoke cannabis experience chest pains – but the opposite effect has been observed targeting CB2 receptors alone. So, to stay on the safer side, if you are a heart patient, it is better to avoid THC rich strains or whole cannabis smoking.
Instead, you can use CBD rich strains of CBD oils to treat and prevent atherosclerosis. The available evidence that supports CBD use for atherosclerosis is scanty, but the role of CB2 receptors in the pathogenesis has been proven. So, we have grounds to assume that CB2 could potentially be used to treat and prevent atherosclerosis. This study has noted that modulation of the endocannabinoid system, particularly via the CB2 receptors (via non-inhalation routes), may have appreciable benefits on atherosclerosis treatment.
We can conclude from this, as the research progresses, that we are better able to understand the complete anti-atherosclerotic benefits of medical cannabis. Cannabis clinicians abroad are recommending edibles, oils, and vaporizers as a safer way to use cannabis – to avoid the negative effects of smoking. Naturally occurring phytocannabinoids contain several cannabinoids, and different cannabinoids exert different effects on atherosclerosis treatment. So, instead of considering THC, CBD-rich strains could be comparatively more effective – and safer!
Written by Lise Gatenby, January 2019
Disclaimer: Medicinal Cannabis Dispensary (MCDSA) aims to be a hub of information about medicinal cannabis, healthy living and the latest scientific research. Always consult your doctor before starting a new treatment.