Your Brain's Immune System and Neuroinflammation
Brain inflammation, or neuroinflammation, is associated with a significant risk for various degenerative brain diseases, including Alzheimer’s and other dementias. It rapidly ages the brain, altering brain function and destroying brain tissue similar to how chronic joint inflammation can destroy joint tissue, leading to joint deformity, stiffness and pain.
There are both immediate and long term complications of neuroinflammation.[1] [2] Short term consequences are that it immediately hinders the transmission speed and conductivity of neurons, which means neurons fire more slowly. This slows down brain function and creates symptoms of brain fog, slower mental speed, slower recall and slower reflexes. Another immediate consequence is that it shuts down energy production in the cells so that brain endurance plummets. This causes limited endurance for mental tasks and may also cause depression.[3] A longer term consequence of chronic neuroinflammation is neuron death and the development of neurogenerative disorders.
Inflammation in the brain can be triggered by inflammation elsewhere in the body, such as infection, inflammatory bowel disease, or an unmanaged autoimmune condition. These issues cause the body to release immune messengers called cytokines that reach the brain in various ways (including directly crossing the blood brain barrier), thereby activating inflammation. [4] [5] [6] [7] [8] [9] Likewise, inflammation or degeneration in the brain can activate the body’s immune system and trigger systemic inflammation, referred to as neurogenic inflammation.[10] [11]
The brain’s immune system
At the root of brain inflammation are microglia cells, the brain’s immune soldiers. There are 10 glia cells for every neuron in the brain, and if you weigh the brain, more than 50% of it is glia cells - in other words, the brain is more glia cells than neurons.
Microglia cells are either in a resting state or an active state. In normal conditions the microglia perform many functions vital for healthy brain function. They dispose of dead neurons, beta amyloid plaque (the substance that predisposes one to Alzheimer’s), and other cellular debris that can interfere with healthy communication between neurons. However, in a heightened state of activation, they create an overzealous immune response that causes brain inflammation.
Several factors increase the risk of activating brain microglia: [12] [13] [14] [15] [16] [17] [18] [19] [20]
- Diabetes and high carb diets, which lead to the production of glycosated end products that activate microglia cells
- Lack of oxygen from poor circulation, lack of exercise, chronic stress response, heart failure, lung disorder, or anemia
- Head trauma
- Autoimmune reaction to neurological tissue
- Gluten, especially for those who are intolerant
- Low brain antioxidant status
- Alcohol and drug abuse
- Environmental toxins
- Systemic inflammation
- A compromised blood brain barrier
Unlike the immune system in other parts of the body, microglia have no built-in ‘off’ switch to turn down the immune response in the brain when it is no longer needed. As a result, they can continue to destroy healthy brain tissue for their entire lifespan. The fact that there are 10 microglia cells for every neuron doesn’t help from this perspective, nor does it help that microglia activation induces a domino effect in which one microglia activates another, leading to persistent neuroinflammation.
How do you recognize if you’re suffering from brain inflammation?
While inflammation sometimes manifests as actual pain or aches in the brain, more often it expresses as brain fog and brain fatigue. When the brain fatigues, it can’t fire sufficiently into the lower two thirds of your brainstem, parasympathetic activity (your ‘rest-and-digest’ functions) and autonomic function (such as digestion and blood pressure regulation) suffer, and the sympathetic stress response goes up. You might experience this as achy joints, suddenly not being able to digest anything, skin flareups, or other inflammatory responses across the body. If you have signs of systemic inflammation, there is a good chance your brain is also inflamed.
The good news is, your brain wants to heal itself and there are many things you can do to get back to your optimal brain health. The first thing is, please don’t take this information and worry or ruminate over it! That kind of stress is itself an activator of inflammation - your thoughts and feelings feed back to your cells constantly and it’s important to make that feedback loop a positive one as much as you can.
What you can do is adopt an anti-inflammatory diet, supplement with botanicals proven to dampen neuroinflammation and support blood flow to the brain, exercise, don’t smoke, manage mental-emotional stress, and get enough sleep (your brain’s detox and repair time). By dampening brain inflammation you can preserve your brain health and slow the aging process, as well as boost mental function and overall wellbeing.
References:
[1] Why neurodegenerative diseases are progressive: uncontrolled inflammation drives disease progression
[2] Microglia and inflammation-mediated neurodegeneration: multiple triggers with a common mechanism
[5] Contribution of systemic inflammation to chronic neurodegeneration
[8] Ghrelin: friend or foe for neuroinflammation
[10] Arthritis and pain. Neurogenic origin of joint pain
[11] Abnormal forebrain activity in functional bowel disorder patients with chronic pain
[12] Brain inflammation is induced by co-morbidities and risk factors for stroke
[13] Microglial response to brain injury: a brief synopsis
[14] Microglia and inflammation-mediated neurodegeneration: multiple triggers with a common mechanism
[15] Microglial activation and chronic neurodegeneration
[16] T cells and microglia as drivers of multiple sclerosis pathology
[17] Features of microglia and neuroinflammation relevant to environmental exposure and neurotoxicity
[18] Neuroinflammation and microglia: considerations and approaches for neurotoxicity assessment
