Endocannabinoid Tone and Arthritis

Arthritis is a common condition that causes inflamed, painful joints.

The term arthritis is used as an umbrella term for several disorders that affect more than one joint.

The most common types of arthritis are osteoarthritis and rheumatoid arthritis.

Arthritis affects people of any age or sex; according to the NHS, more than 10 million people have arthritis or similar joint conditions in the UK.

Most forms of arthritis worsen with age and can result in chronic pain, restricted mobility and permanent changes to joints.

While arthritis can affect any joint, it's most often reported in the hands, spine, knees and hips.

The most common symptoms of arthritis are:

• Inflamed, swollen joints
• Painful, tender joints
• Thin, rough cartilage around affected joints
• Bone spurs may develop in joints
• Stiff joints with restricted movement
• The skin over the affected joint may become warm and red
• Weak joints and muscle wasting
• Breakdown of bone and cartilage

Arthritis can have various causes, including:

• General wear and tear over time
• Ageing of bone, cartilage and connective tissue
• Injury to the joints
• Obesity
• Some types of arthritis are caused by autoimmune disorders
• A family history of arthritis or related conditions
• Weak muscles around joints

There are no current treatments that can cure arthritis, so doctors work on reducing the symptoms and slowing its progression. Some methods used to achieve this are:

• Lifestyle changes
• Pain medication
• Physiotherapy
• Surgery

What is CBD?

CBD is one of over 100 cannabinoids found in plants of the cannabis genus. It's non-intoxicating and is extracted from hemp to be used as a food supplement.

The CBD extract is combined with other beneficial ingredients to make various products, including oils, capsules, e-liquids or gummies.

When you consume CBD, it enters your cells and tissues and interacts with a broad range of chemical messenger molecules, enzymes and receptors.

These interactions support your body's ability to restore your body systems to a state of healthy balance.

Learn more about CBD with our guide: CBD 101 – Everything you need to know

CBD and Your Endocannabinoid Tone

CBD works in your body in many different ways, but one of the most vital interactions is how it stimulates the endocannabinoid system (ECS) and raises your endocannabinoid tone:

What is the endocannabinoid system?

The endocannabinoid system is a collection of signal molecules (endocannabinoids), receptors and enzymes.

It's active throughout the body, particularly in the central and peripheral nervous systems. 

When the ECS is activated, it makes tiny chemical adjustments that enhance the signalling capacity of cells within your body.

This allows your various body systems to communicate effectively and quickly restore a healthy balance following damage or illness.

What is endocannabinoid tone?

Endocannabinoid tone refers to the level of potential endocannabinoid activity in your body and the ability of your endocannabinoid system to respond to any problems.

Several factors can affect this, including genetics, diet, stress, and disease.

If your endocannabinoid tone is low, your endocannabinoid system is unlikely to be able to restore your body systems to a state of healthy balance. As a result, you may feel unwell or experience symptoms related to anxiety. 

Regular consumption of CBD can stimulate the action of your endocannabinoid system (ECS) and raise your tone. 

To learn more about how CBD raises your endocannabinoid tone, you can read our article: Endocannabinoid Tone and CBD

Key terms:

CB1 and CB2 – These are the most common endocannabinoid receptors.

• CB1 is found in the central nervous system.
• CB2 is present in the central nervous system, the peripheral nervous system and in immune cells throughout the body

Anandamide (AEA) and 2-Arachidonoylglycerol (2-AG) – These are endocannabinoid signalling molecules present in humans and animals. They can interact with various chemical receptors, including CB1 and CB2.

Endocannabinoid Tone and Osteoarthritis

Osteoarthritis is the most common type of arthritis in the UK.

It occurs when joint cartilage breaks down, causing pain, swelling, and friction.

This is often a result of overuse, old age or injury. It usually begins after the age of 40, but if other conditions or injuries trigger it, it can start earlier.

While no studies have found any indication that the endocannabinoid system could stimulate recovery from the physical changes produced by osteoarthritis, there are several that indicate that a high endocannabinoid tone will help to desensitise the effective areas and reduce pain in a way that most current pain medication can't.

Scientists have found that when osteoarthritis starts to produce pain, the pathways from the pain receptors in and around the joints to the spinal cord and the brain become sensitised.

As a result, more receptors are made, meaning that people who have experienced pain from osteoarthritis for several weeks are more sensitive to it than those who've just started to experience it.

Sensitisation means that the same level of pain is perceived in the brain from smaller stimulation than before.

This gives the experience of worsening pain sensations when the actual physical effect of the osteoarthritis may be the same.

This sensitisation can occur at the site of the pain and in the spinal cord.

However, in people with a naturally high endocannabinoid tone, activation of CB1 receptors closes the chemical channels that support this chain of events.

So, while many painkillers cannot reduce pain produced by this sensitisation, a naturally high endocannabinoid tone can.

As well as reducing the pain sensitising mechanisms, a naturally high endocannabinoid tone shows promise as an effective way to manage the chronic pain produced by osteoarthritis.

This happens in several ways:

1. When anandamide binds with CB1 receptors on nerve cells, it activates channels that alter the electrical and chemical activity of the neuron. This doesn't stop the transmission of pain signals, but regulates and adjusts them.
2. CB2 receptors are found throughout your body in tissues, organs and immune cells. When activated by endocannabinoids, they inhibit the release of several chemical signalling molecules, including cytokines. Scientists have found that the expression of cytokinesis linked to many chronic pain conditions, and controlling them is key to effective pain management.
3. Both receptors also produce a range of other effects that regulate chronic pain when activated by anandamide or 2AG. This includes the release of endorphins, moderation of inflammation and the regulation of neurotransmitters that control pain processing within the central nervous system.

An exceptionally detailed study in 2021 simulated the degenerative effects of osteoarthritis in rats by injecting them with sodium monoiodoacetate.

It then looked at the behaviour of all the receptors that can interact with endocannabinoids or plant cannabinoids. 

The researchers concluded that when some of the receptors were activated they produced modulating effects on the action of osteoarthritis.

The most effective receptor was PPARY receptors.

PPARY receptors are nuclear receptors that can mediate the anti-inflammatory properties of cannabinoids.

When activated, it produces a range of effects that controls inflammation and supports the endocannabinoid system to interrupt the sensitisation of the pain pathway. 

When endocannabinoids and relevant receptors were activated in someone with a high endocannabinoid tone, the pain produced by joint movement was decreased.

However, they also noticed that there didn't seem to be any reduction in the sensitivity of joints to high temperatures, which is a common feature of arthritic joints.

Rheumatoid Arthritis and your Endocannabinoid Tone

Rheumatoid arthritis is an autoimmune condition that makes the body's own defence system attack and break down the cartilage, tendons, ligaments and bone.

This causes pain, inflammation and the eventual complete breakdown of the joints and surrounding tissue.

It's not yet understood what causes rheumatoid arthritis, but contributing factors include:

• Family history
• It seems to be more common in women and could be linked to oestrogen
• Smoking

There is no cure for rheumatoid arthritis, but current treatments such as medication, lifestyle changes and surgery can slow the progression and prevent complete joint breakdown.

When rheumatoid arthritis first starts, immune cells are produced, then they begin to invade the joint fluid (synovial fluid), bone and cartilage.

Doctors found that the synovial fluid of people with rheumatoid arthritis contained both endocannabinoids (anandamide and 2-AG) and endocannabinoid receptors (CB1 and CB2).

This was particularly interesting because they're not present in the synovial fluid of people with healthy joints.

Consequently, a 2015 study concluded that the endocannabinoid system might be part of the body's protective response to the autoimmune action.

The scientists theorised that a naturally high endocannabinoid tone could provide better protection against the damaging actions of rheumatoid arthritis. 

They went on to explain that in affected joints, the body attempts to produce more CB2 receptors.

When these receptors are activated, they activate a feedback loop to prevent inflammation and bone erosion.