Friday, November 18, 2011

Acute and Chronic Inflammation - More Than Just A Pain

If you’ve ever stubbed your toe really hard, suffered an accidental cut, or sprained your ankle, you probably know almost all of the symptoms of inflammation without even realizing it. Pain, redness, and swelling are the immediate and lingering response to injuries like this. It’s no secret why we call the area “inflamed” because an injury like this feels hot and painful.

Inflammation is a critical first step in repairing damage in your body, be it from injury or illness. We are self healing organisms and without inflammation we would be in trouble. On the other hand, research is now finding that excessive and prolonged inflammation is associated with many serious diseases including cancer, asthma, heart disease, and even obesity.

Preventing and controlling an excessive inflammatory response may be crucial to your staying healthy. So where do you start?

What is Inflammation?

A good place to start is in understanding what inflammation is and why it exists. Inflammation is part of a very complex immune response that your body uses primarily to prevent invasion by pathogens (e.g. germs and microbes like viruses and bacteria, fungus, or disease causing prions). The combination of heat to kill off microbes, increased blood flow to bring in more cells of the immune system, and pain to let you know that there is a problem helps to fight and remove harmful bacteria and germs.

Inflammation is also the body’s generic way of responding to damage. This damage can be from an illness (bacteria, virus, etc.), from a physical injury, or a chemical process (as in certain types of heart disease). Inflammation is a less specific immune response, kind of a generalized first response to any damage anywhere in your body. The rest of the immune system targets specific things (microbes, etc.) to maintain health, but often inflammation is one of the primary ways the immune system starts to get into action. In fact, without inflammation, we wouldn’t be able to heal from injury or most illnesses.

The Reason Why Inflammation is Good

The first reaction your body has to damaged cells is that they trigger the immune system, which kicks into high gear and starts an offensive against anything that might do further damage. Due to increased blood flow in the area from the first stages of inflammation, repair pathways kick in and start to rebuild the injured tissues from the inside out, while the inflammatory response tries to protect this repair process and the area around it. This is good, because if your inflammatory processes didn't do that, microbes or other pathogens would be able to easily come in and make short work of the repair cells trying to fix the problem, leading to infection or worse.

But, there's a cost to this "protection"; inflammatory cells are generally overzealous and will do damage to things they shouldn't. It's a bit of a trade-off, but in the long run, a little extra damage or prolonged healing time is a small price to pay for staving off a potentially dangerous infection. To further ensure that the area doesn't get infected, your body sets up something that makes you not want to touch that wound to anything -- pain.

The Inflammatory Cascade

The medical acronym for the symptoms of inflammation is PRISH. Pain, Redness, Immobility (loss of mobility or function), Swelling, and Heat are the five major symptoms of inflammation. In most injuries, inflammation is the first response your body has (other than pain signals to the brain) to protect itself. It turns out that there is a good reason for the order of events.

Inflammation can occur even
in internal injuries and shows
the symptoms of PRISH. 
Inflammation generally starts and progresses the same way. Some part of your body experiences injury or irritation and triggers the immune system. The first thing your body does in response is release vasodilators, chemicals that cause your blood vessels and arteries to open up and deliver more blood to the affected area. You experience this as redness, heat, and swelling. When we are told to “put ice on it” immediately after an injury, it is to help narrow the small blood vessels in the area and therefore the inflammation that leads to pain.

Your body wants to push more blood to the injured area because blood contains a number of different cells related to healing from the immune system (white blood cells, granulocytes, lymphocytes, etc.). Increased blood flow can also deliver more energy and resources to the surrounding area to help with repairs.

After the injured area receives this increased flow of blood, some of the fluid from the bloodstream leaves the blood vessels and starts to “sweep” through the area of damage. Typically, this increase in fluid is what causes the bulk of the swelling that most people associate with inflammation.

This increase in blood flow is your bodies attempt to gather up foreign debris (either microbes, dirt or anything else from outside the body) and deliver it to your lymph nodes where your immune system can learn how to battle this foreign invader. This mechanism is particularly helpful when you get any kind of foreign body penetrating the skin where microbes may decide to hitch a ride. A splinter is a simple example of a foreign body that may introduce microbes into your injury and that your immune system must figure out how to clear.

Once the immune system has a handle on the problem, specialized immune cells (e.g. lymphocytes or T cells, Basophils or B cells) take over fighting for you and try to kill or clear away the invading problem.

Granulocyte cells migrate
from the bloodstream and
work to envelop bacteria
or other contaminants.
At this point, the inflammatory cascade serves one final purpose. The increased sensation of pain caused by the effects of inflammation (swelling causing nerves to fire with less provocation) serves to remind us, often painfully, not to touch any damaged part of our body with anything at all. This prevents potential infection by limiting our exposure to microbes and also causes you to rest the affected area so that it has time to heal. 

Acute vs Chronic Inflammation

While acute inflammation is absolutely essential to our ability to heal, sometimes inflammation does not settle down and this can eventually lead to chronic inflammation. Chronic inflammation develops for a number of reasons.

If the reason for the acute inflammation does not resolve, it may develop into chronic inflammation. So, for example, if you have a disc in your back that gets irritated from sitting too long or bending incorrectly, your body will try to heal this “injury” by starting the inflammatory cascade. If you don’t change your habits, then you set up the conditions for chronic inflammation. The body just keeps trying to heal the problem but you are never giving your body the conditions to truly heal.

The same mechanism occurs if you eat foods to which you are sensitive or allergic (e.g gluten, eggs, milk products, etc.) that cause your intestines to be irritated. Your body will cause inflammation in your intestines which may eventually lead to chronic inflammation and chronic health problems like Irritable Bowel Syndrome. Unfortunately, once inflammation starts somewhere in your body the effects are felt far and wide. So, while it might be your gut where the inflammation first starts, you may end up with a chronic inflammatory problem almost anywhere else in your body, causing anything from asthma to obesity.

Furthermore, since the inflammatory cascade doesn’t distinguish particularly well between “good” and “bad” cells. Over a long period of time, chronic inflammation both helps heal and also kills off cells in the area. Over a long period of time, this constant battle has a notable effect; your body has to expend extra energy both maintaining inflammation and also repairing the cells that are mistaken as bad by the immune system and destroyed. If the chronic inflammation continues for long enough, it can even develop into more serious conditions.

What kinds of disorders are linked to chronic inflammation?

Chronic inflammation has been linked to a wide variety of disorders pretty much everywhere in the body.

These can include:

  • Acne vulgaris
  • Obesity
  • Asthma
  • Autoimmune diseases
  • Celiac disease
  • Chronic prostatitis
  • Glomerulonephritis (damage to the kidneys)
  • Atherosclerosis (hardening and blockages of the arteries)
  • Hypersensitivities and allergic reactions
  • Inflammatory bowel diseases
  • Pelvic inflammatory disease
  • Rheumatoid arthritis
  • Sarcoidosis
  • Transplant rejection
  • Vasculitis
  • Interstitial cystitis

Obesity and Chronic Inflammation

The relationship between chronic inflammation and obesity is complex. Many studies have shown that the two are linked, but we still don’t really know if one or the other is the cause or effect. It is known, however, that the single best way to reduce chronic inflammation due to obesity is to lose weight (but only down to a normal, healthy weight).

The combination of obesity and chronic inflammation creates a feedback effect. The immune system sometimes mistakes fat (adipose cells) as a microbial intruder. Since the first response to discovering an infection is inflammation, more immune cells are sent in to deal with the supposed foreign contaminant (adipose cells). Generally speaking, adipose cells are rarely alone, so as the area gets flooded with immune cells, they are more likely to mistake surrounding adipose cells as intruders. This feedback loop can cause chronic inflammation to continue indefinitely, causing ongoing damage to surrounding cells.

It’s now known that chronic inflammation and obesity are contributing factors to heart disease, cancer, and a number of other illnesses. In atherosclerosis, a chemical irritant in the wall of the artery (oxidized LDL from the blood stream) causes damage. Since the immune system doesn’t have a good way of dealing with this damage, inflammation does its best and uses cells called granulomas to physically wall off the damaged area. As more damage occurs, the containment process starts to close off the arteries supplying blood to the heart. In cancer, inflammation typically causes increased blood flow to areas of the body where small groups of cancerous cells may have developed, causing them to get the nutrients that they need to start growing.

Chronic inflammation can also contribute to obesity, while at the same time reducing muscle mass. This combination of effects tends to reinforce itself as the reduced muscle mass reduces the ability to burn fat, the storage of which in the body leads to an increased inflammatory response.

Diet can also have a big impact on chronic inflammation, both positively and negatively. Meals high in saturated fat or high in calories are associated with increases in the marker chemicals of inflammation. Meals high in omega-3 fatty acids (like oily fish) can help to reduce inflammatory precursor chemicals.

How can I lower or prevent chronic inflammation?

Many studies have been done in recent years testing everything from diet to exercise to see what kind of changes can be made to chronic inflammation. The evidence is mixed except for one basic fact which emerges in almost all of the studies done. If you are even slightly overweight, losing some weight is the most reliable and best way to reduce chronic inflammation.

Fish Oil is high in
omega-3 fatty acids and
can help lower
inflammation.
Other options exist that are known to decrease the inflammatory response. While specific studies have not yet conclusively found that these decrease chronic inflammation, the fact that they are known to help decrease the inflammatory cascade is good enough reason to consider them potentially valuable.

Omega-3 fatty acids are extremely helpful in reducing inflammation. They are used by your body to produce chemicals called eicosanoids, which are crucial in mediating inflammatory responses. When eicosanoids are made using omega-3 fatty acids, they are anti-inflammatory, sending signals to terminate chemicals that cause inflammation. When they are made with the much more common omega-6 fatty acids, they are pro-inflammatory (they cause inflammation). Your body naturally prefers to make eicosanoids out of omega-3 fatty acids, but will use omega-6 if none is available. So, increasing your intake of omega-3 fatty acids can help manage this source of inflammation causing chemicals in your body.

Omega-3 fatty acids are formed in the chloroplasts of green leaves and algae. While seaweed and algae are the primary source of omega-3 fatty acids present in fish, grass is the source of omega-3 fatty acids present in grass fed meats. However, if grass fed animals are “finished” on grains like corn (a common practice in the meat industry), the levels of omega-6 go up while omega-3 decreases the longer they are away from eating only grass.

Foods rich in omega-3 fatty acids include oily cold water fish (e.g. salmon, anchovies, sardines, herring, mackerel) and fish oil supplements, flaxseed oil, grass-fed beef (only if grass fed for the entirety of its life), eggs from chickens fed on a diet of greens and insects (and especially not fed soy or corn), brains of mammals (especially lamb), and microalgae (which is okay for vegans).

Legumes (peas, beans, chickpeas, lentils, peanuts, etc.) especially, show a link to decreasing inflammatory marker chemicals. In addition, a number of foods can prevent precursors (NF-κB) to inflammation; these include: grapes (dark red), basil, gooseberries, garlic, almonds, cashews, walnuts, mango, prunes, raisins, pecans, figs, fenugreek, flax, lemon grass, nutmeg, saffron, dill, oregano, coriander, parsley, camphor, licorice, caraway seeds, mustard, tamarind, rosemary, onions, turmeric, cumin, black pepper, cinnamon, coriander, red pepper, clove, ginger, fennel, mint, and sesame seeds.

Some dietary changes can help to reduce inflammation, though the mechanisms as to why are not fully understood. It is likely that the dietary changes, which often lead to weight loss in study participants, are due in no small part to the weight loss itself.

Medications for Inflammation

Allopathic medicine sometimes attempts to treat inflammation using pharmaceutical medications. These can include NSAIDs (non-steroidal anti-inflammatory drugs), which target the production of certain enzymes that cause inflammation. The primary reason most people use NSAIDs is to reduce pain following an injury or for a chronic condition like rheumatoid arthritis. While these drugs may be useful in cases of acute inflammation, due to injury, long term use of NSAIDs can lead to other problems.

Other, more powerful drugs are used to treat severe inflammation that can be life threatening. Steroids like Prednisone are used to treat sever athsma attacks, anaphylactic reactions (like in bee stings or severe allergic reactions), certain kinds of cancers, infections, and as part of a combination of drugs used in organ transplants to prevent rejection. Steroids have a number of serious side effects ranging from psychiatric side effects to necrosis of the hip (your hip bone actually dies). While a powerful option for acute inflammation, these should not be used for a long period of time, where the risk of developing illnesses like Cushing’s Disease is greatly increased.

Different Approaches in Medicine:

Though allopathic and CAM practitioners and researchers approach the issue of inflammation differently, their conclusions are very similar. Inflammation is a systemic condition that is caused by or may cause many different illnesses. Short term inflammation is helpful to protect your body from illness and injury, but chronic inflammation is bad.

CAM practitioners have believed for a long time that inflammation is caused by some sort of underlying problem, be it illness or imbalance. CAM treatments and techniques are aimed at discovering and addressing the underlying cause of inflammation.

Allopathic medical practitioners and researchers, after many years of research into inflammation, now know many of the mechanisms and causes of inflammation. Historically, allopathic practitioners have looked to treat the diseases that are caused by inflammation separately. As research has clarified the role of chronic inflammation in chronic illness, allopathic practitioners are starting to suggest to their patients adopt lifestyle changes such as diet as an option for treating these conditions. Unfortunately, only practitioners who approach it from both perspectives realize that not only does the chronic inflammation need to be treated (along with the disorders it causes), but that they should look deeper, for the underlying reasons for the inflammation.

Inflammation is something to be respected. It helps us to heal but in overdrive it leads to disease. Finding a practitioner who understands the process of inflammation, looks for the underlying causes and who is familiar with the traditional and complementary approaches to tackling this problem will serve you best in the long run.


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Resources:
Inflammation and Insulin Resistance
Inflammation and Cancer
Inflammation: What You Need to Know
The role of apoptosis in wound healing
Resolution of inflammation: the beginning programs the end
Elevated levels of interleukin-6 are reduced in serum and subcutaneous adipose tissue of obese women after weight loss
The anti-inflammatory effect of excercise
Fatty acids from fish: the anti-inflammatory potential of long-chain omega-3 fatty acids


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Researched and written by Dr. Rebecca Malamed, M.D. with assistance from Mr. Malcolm Potter.

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