In the last article we published on inflammation, we talked about the connections between inflammation and certain diseases. We even pointed out that many of the diseases cannabis is useful in treating are linked with chronic inflammation. But to really understand how cannabis can help in treating inflammation, we have to get into the nitty-gritty of what inflammation actually is.
Put your geeky science glasses on because this is going to be a crash course in human biology.
Inflammation is arguably one of the body’s most important immune responses. It’s how the body responds to an attack from an external pathogen, to injury or infection. It’s completely necessary for survival and without it, humans wouldn’t live for very long.
Inflammation is not always a bad thing, and inflammation is not inherently pathogenic. Inflammation is the response from the immune system — not the disease itself. However, pathogenic immune responses do exist, such as in autoimmune diseases. Sometimes, inflammation becomes chronic and actually causes more damage than good. This is the kind of inflammation that requires medical intervention.
As we touched on in the last article, dementia is associated with chronic brain inflammation. Brain inflammation has also been observed during seizures, and we also know that researchers are making breakthrough discoveries about the role of inflammation in mental health such as depression. This research makes inflammation a target in the treatment of these diseases.
So before we get into the pharmacological actions of cannabis in terms of inflammation, let’s breakdown how and why inflammation happens.
What is inflammation and how does it happen?
- The acute phase
- Tissue formation
- The remodelling phase
These three phases are all part of normal inflammatory physiology. It means that whenever somebody gets an injury or infection, this process takes place as part of healing. Let’s have a look at it in a little more detail.
Let’s assume that you acquire an injury and the tissue or skin is broken or damaged. This marks the beginning of the inflammatory process. Upon injury, specialised cells near to the site send chemical signals that dilate the nearby blood vessels and make them more permeable. These include histamine, prostaglandins, kinins, etc.
The arrival of histamine and prostaglandins on the scene is what causes the redness, soreness, and itchiness that’s associated with a tissue injury. As the capillaries are more permeable and fluids and proteins leak from the capillaries, pain arrives as the site of the injury.
These chemical mediators also attract more specialized immune cells to the area that can come in and “police” the infection. Leukocytes such as neutrophils are able to arrive at the injury faster because of capillary dilation. They are also able to move through the capillary thanks to increased permeability, and can actually enter the site of infection.
Once these specialized immune cells have arrived, they essentially “consume” or “destroy” pathogenic material, dead tissue, and anything that isn’t required at the site. This is called phagocytosis, where a cell swallows pathogenic material and digests and destroys it.
Once the infection has been handled by these specialised immune cells, tissue formation and the remodelling phase occur. This is when a scar forms or when the tissue heals back to its original state.
This is all part of normal, natural inflammation. Up until this point, it’s considered normal. But something happens that makes inflammation turn chronic.
Why and how does inflammation become chronic?
There are a number of reasons that chronic inflammation might occur. As we mentioned, it’s usually at this point that inflammation turns from a good thing into a bad thing.
Some of the reasons for chronic inflammation include:
- Failure of the immune system to completely remove the pathogen or infectious organism such as bacteria, fungi, viruses, or protozoa. Without complete removal, small parts of the organism remain in the body and cause low-grade, chronic inflammation.
- Constant exposure to a low-level irritant or pollutant in the air or at workplaces.
- Autoimmune disorders where the body’s immune system attacks healthy tissues causing inflammation where none is required.
- Recurrent episodes of acute inflammation such as repeated injury or repeated infection.
- Sometimes, as is the case with rheumatoid arthritis, chronic inflammation is an independent physiological response that doesn’t follow acute inflammation.
Researchers also acknowledge the role that lifestyle factors have to play in chronic inflammation. Diet, obesity, smoking, and excessive alcohol consumption are all linked to the development of chronic inflammation. Research also shows that intense stress over activates the immune system which leads to chronic inflammation.
How does cannabis reduce inflammation?
A mountain of research has gone into the treatment of inflammation with cannabis. A number of different mechanisms are thought to be behind THC and CBD’s ability to reduce inflammation, so let’s have a look at each of these cannabinoids separately.
CBD and inflammation.
Clinical studies investigating CBD and inflammation have confirmed that CBD might reduce inflammation in the following ways:
- By reducing the level of pro-inflammatory cytokines. These are part of the chemical mediators that create inflammation mentioned earlier in this article about how inflammation occurs.
- CBD might inhibit T-cell proliferation. T-cells are among the specialized immune cells that come to the site of injury to deal with the injury or infection.
- CBD might help to reduce the adhesion of specialised cells to the capillary membrane, therefore disallowing them from exiting the capillary and performing inflammatory actions.
- Finally, CBD induces T-cell apoptosis, which is the programmed death of specialized immune cells that cause inflammation.
THC and inflammation.
It’s thought that THC shares some of the anti-inflammatory mechanisms of action as CBD . Primarily, THC is well known to induce apoptosis in immune cell populations, especially among macrophages and T-cells. However, there is no evidence that THC reduces the amount of pro-inflammatory cytokines or any of the other chemical mediators in the inflammatory process.
Antioxidants and their role in inflammation
We’ve shown a few of the ways that THC and CBD have a direct effect on the inflammatory process. But cannabinoids work in indirect ways, too. Both THC and CBD are antioxidants, which means that they can counteract reactive oxygen species (ROS). These ROS are a result of normal physiological processes, but failure to counteract or remove them can lead to inflammation, disease, and cancer.
In fact, CBD can prevent the formation of superoxide radicals. This is a direct way that CBD exerts its antioxidant properties.
Why are the antioxidant properties of THC and CBD important to inflammation then?
Well, as we mentioned before, poor diet, obesity, alcohol consumption and smoking are risk factors in inflammation. That’s because they cause a lot of reactive oxygen species, and because a poor diet lacks antioxidants to counteract them.
But THC and CBD aren’t alone in being antioxidant rich. Many plants are antioxidant rich, and this is why a poor diet is linked with a high level of oxidative stress and reactive oxygen species. This is why the antioxidant properties of cannabis are more of a secondary and non-direct way of reducing inflammation. And because these mechanisms aren’t exclusive to cannabis, cannabis isn’t the only way you can get the same results.
From inflammation to healing
Not all inflammation was created equal. Some people suffer chronic inflammation as a result of autoimmune diseases like Crohn’s disease. Others suffer chronic inflammation because of repeated exposure to irritants such as those who work in mines or in factories. Because of this, not all inflammation should be treated equally. For some people, simply removing the irritating factor (such as a chemical pollutant) is enough for healing to begin.
It’s easy to plug cannabis straight into the biomedical model we typically use for disease: there’s a drug for each disease, and there’s very little variance on that. Even though cannabis is anti-inflammatory, it doesn’t mean it’s going to cure all kinds of inflammation. If a person is obese, smokes cigarettes and drinks a lot of alcohol, then there’s no amount of cannabis that’s going to undo any inflammation caused.
With that in mind, there are certain inflammatory conditions that cannabis has an affinity for — like inflammatory bowel disease! In the coming weeks, we’re bringing you some articles about the kinds of inflammatory conditions that cannabis shows therapeutic potential. Stay with us on this journey through cannabis and its potential to heal inflammation.