What is Chronic Inflammation?
Inflammation is the body’s response to something gone wrong. It is a component of the body’s immune response, a complex and elegant system with the ability to recognize and destroy invaders that have the potential to harm us.
Inflammation 101
Inflammation is the body’s first line of defense. Without it, we’re wide open to opportunistic infection, so that exposure to something as innocuous as the common cold or a paper cut could have fatal consequences.
When you catch a cold or cut yourself, an extremely sophisticated alarm system goes off inside your cells. Certain cells identify the virus or injury, report the nature of the attack, and request the necessary reinforcements to launch a counterattack. Cytokines, adipokines, and eicosanoids, the messengers produced by surveillance cells and fat tissue, dispatch ground troops—white blood cells—to combat the infection. This offensive must be carefully calibrated: sufficiently brutal to immobilize the enemy, yet controlled enough not to completely destroy the cells and tissues surrounding the battlefield.
When is Inflammation Bad?
Inflammatory disease begins with an exaggeration of the body’s normal inflammatory response.
If our inflammatory system is reacting to a real threat, then it’s keeping the body safe. But if it overreacts—if, say, it interprets a harmless substance (like peanuts) or the body’s own tissue (like cartilage) as a dangerous invader—then the normal inflammatory response becomes a disease state (severe allergies and arthritis, in the examples here). Sometimes the threat is real, but the inflammatory response is dramatically exaggerated. When this happens, the inflammatory response never stands down, even after the threat is long gone. This, too, leads to inflammatory disease.
Another, more prevalent danger—especially in developed countries—is a relatively low-level, chronic inflammatory state, when the immune system is continuously activated by adipokines from fat tissue. This can lead to the slow but steady destruction of tissues and organs. More importantly, it places the organ systems that are most genetically predisposed to the inflammation at high and constant risk for harm. For example, chronic inflammation can cause the body to attack the islet beta cells in the pancreas. Eventually, the cells aren’t able to produce insulin. The end result: diabetes.
Like Using a Blow Torch to light a Candle
Now a little bit of “collateral damage” is to be expected in the wake of the inflammatory response. It’s a small price to pay for a successfully vanquished infection. Once the immune system has eliminated the intruder, the injured tissues should heal normally, and life goes on. But when the body launches a full-scale inflammatory response against something inoffensive, any tissues that have the misfortune of being close by are also destroyed. Chronic inflammation is like using a blowtorch to light a candle on a birthday cake. In a person with inflammatory disease, the body adds insult to injury by sending ever more inflammatory reinforcements to compensate for the damage from the initial inflammatory response.
Essentially, inflammatory disease occurs when the body turns its own defenses against itself in a “friendly fire” scenario. It inaccurately detects what it perceives to be a threat, or it overreacts to a real threat; it causes damage; then it overreacts again and again with subsequent inflammatory responses in an endless negative-feedback loop that scorches the battlefield. This is chronic inflammation, and it manifests itself as heart disease, diabetes, arthritis, asthma, allergies, COPD, Crohn’s disease, psoriasis, and cancer, to mention only a few.
Same Problem, Different Location
There are many different inflammatory diseases, yet all of them share the same underlying driver: an inappropriate inflammatory response. The difference between them is where the inflammatory response is taking place. (There are other differences, especially regarding which parts of the immune system are participating in the inflammatory response, but this explanation serves our purposes here.)
Chronic inflammation localized in the coronary arteries surrounding the heart leads to atherosclerosis and heart disease. In diabetes, as mentioned earlier, the body mistakenly identifies the islet beta cells in the pancreas as foreign invaders and destroys them so that they no longer produce insulin. When inflammatory cells such as eosinophils or neutrophils invade the small airways of the lungs, they cause asthma. Arthritis, meanwhile, occurs when the synovium—a thin, specialized tissue responsible for the production of fluid that lubricates joints—becomes inflamed.
The list goes on and on. Inflammation in the upper bowel? Crohn’s disease. Lower bowel? Ulcerative colitis. The underlying process is the same; it’s just the location and symptoms that change.
