Anti-Inflammatory Diet

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Monday, September 29, 2008

Vagus Nerve Controls Intestinal Inflammation

Macrophages release inflammatory signals (TNF, IL-1, IL-6, IL-18) that result in tissue inflammation. Nicotine is anti-inflammatory by acting on the acetylcholine receptors normally responsive to acetylcholine released by the vagus nerve. Acupuncture is anti-inflammatory by stimulating the vagus nerve-mediated effects on macrophages.

The relationship between the nervous and immune systems has been accepted as a reality, but has been elusive. Numerous examples in alternative medicine appear to show that a variety of treatments have immunological impacts, but explanations based on cellular biology have been slow to materialize. Here I will discuss some of the recent experiments that reveal obvious connections between nerves and macrophages that may explain in medical terms at least part of the efficacy of acupuncture.

Dilation of blood vessels that causes reddening, swelling and warmth of tissue inflammation results from changes at the cellular level. If the sentinel cells of a tissue, macrophages, are exposed to a bacterium, for example, receptors on the surface of the macrophages bind fragments of the bacterial cell wall, i.e. lipopolysaccharide (LPS) or endotoxin, and signal the expression of five dozen genes. Among these genes are inflammatory mediators, TNF, IL-1, IL-6, IL-18, that are released from the macrophages and trigger behavioral changes in the surrounding cells of the tissue, which are observed as inflammation.

Expression of the inflammatory genes is controlled by a master transcription factor, NFkB. Thus, LPS will signal a macrophage, NFkB is activated, inflammatory genes are expressed, mediators are secreted and tissue inflammation is observed. Dozens of different inputs determine if NFkB will be activated or quieted. Nicotine for example has been observed to block inflammation by LPS.

It has been shown that macrophages also have receptors for the neurotransmitter acetylcholine that is released by branches of the vagus nerve in the intestines. It has also been recently shown that excitation of the vagus nerve releases acetylcholine and blocks the response of intestinal macrophages to LPS. Thus, vagus stimulation is anti-inflammatory and blocks NFkB activation through a competing transcription factor, STAT3. Nicotine acts by binding to the acetylcholine receptors of the macrophages and is similarly anti-inflammatory.

Acupuncture appears to work by needle stimulation of the vagus nerve that sends signals to the brain. Returning nerve impulses via the vagus nerve subsequently release acetylcholine back into the surrounding tissue and block inflammation. In this context, acupuncture would be exploiting an existing inflammation dampening system, that would serve to localize spreading inflammatory signaling and emphasize the source of inflammation for action by the circulating elements of the immune system.

9 comments:

Anonymous said...

Dr. Ayer, you seem like the person I need to talk to.

Two years ago I began to have severe head pressure and dizziness after eating. Blood sugar abnormalities were ruled out and it has been a mystery as to why this is happening. My cardiologist suggested that it is from venous pooling in my abdomen, which makes sense because I sometimes get lightheaded and my legs feel heavy. Once during one of these episodes I attempted to check my blood sugar and my blood was so watery I couldn't get it in the test strip. Another time during one of these episodes my gums began to bleed. Both of these things seem indicative of excessive venous pooling. From what I understand it is the vagus nerve that controls digestion.

At the same time that I began having these episodes I was also getting a lot of digestion problems and intestinal inflammation. My gastrologist game me some digestive enzymes to take which caused a severe headache, a weird brain swelling feeling, and intestinal bleeding. He told me this was a very unusual reaction and didn't have any answers as to why this happened. Since taking the enzymes I haven't been able to tolerate health supplements. Vitamins, herbs, probiotics all make me very spaced out and I feel as though my brain is being pulled downward.

I have theorized that there may be extensive inflammation in my vagus nerve, likely around the digestive area. I occasionally exhibit symptoms of POTS, and I feel that my condition is some type of dysautonomia. Could you possibly make any suggestions as to what could be happening with me?

Thank you.

Steve said...

Dear Sir and Dr. Ayer,

I have been experiencing similar symptoms and am interested in determining if I have the same affliction. Was there any discussion on this querry?

Thank you,

Steve

Dr. N said...

RE: Anonymous and Steve,

Seems you both are developing orthostatic hypotension is response to the normal shunting of blood to the intestinal tract with meals.

This is often due to a weakness of a different part of the autonomic nervous system, the sympathetic arm. It is referred to as sympathetic withdrawal.

I have found a reduction in carbohydrates to less than 100 grams per day and a temporary increase in sodium (about a cup of chicken broth twice daily for 2-3 weeks) generaly helps this to resolve in most of my patients.

Dr. Art Ayers said...

Dr. N,
Thanks for your knowledgeable input. I rely on my readers to supply insights from their own observations.

Me said...

I have had this issue for almost 3 years now. I was on 50 grams or less of carbs back then and eating mostly meat and fat since 2009. I have trouble with POTS, sometimes resting heart rate is elevated as well, and awful, daily, 24/7 abdominal distention. Increased sodium has not helped. Mid-April I was able to stop the beta blocker I was prescribed - did not take it for a whole week. From one day to the next my first morning HR went from around 105 to around 155 and this morning 166. I have no idea what happened? Any suggestions for me, good doctors, articles to read, treatments, etc.?

The beta blocker is a band aid that I do not like. I would like to get to the root of the problem. Can vagus nerve function be tested?

Thank you for any input!!

Anonymous said...

It's a little late to reply to these comments, but check out www.prettyill.com for some new ideas about POTS, mast cells and low grade hydrocephalis. I'm learning a lot there and beginning treatment for mast cell syndrome to alleviate gastrointestinal issues. Still trying to wrap my brain around it all.

Anonymous said...

I would love to know if anonymous ever got an answer to the head pressure problem. I have had horrible head pressure for the last six months. I am being told it is from a neck muscle spasm, but the only chance this is near the truth is if in some way the vagus nerve is being compressed at that point in my neck. It is definitely related to digestive problems.

Cristina Tarahumara said...

I had symptoms similar to the first anonymous commenter, dizziness after eating, severe intestinal cramps... In 2010 I did an intensive intestinal cleanse (most of it being doses of bentonite, chlorella, cilantro, parsley, PectaSol/pectin C...) Anyway after the cleanse my nausea and dizziness after eating (along with a host of other terrible effects have disappeared) not all of my symptoms are gone but I feel like a new person. Just wanted to share

Anonymous said...

Everyone would benefit from titrating to bowel tolerance on vitamin c. This will heal the digestive issues and vagus nerve. It has been my blessing!