Migrating motor complex

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Migrating motor complex, also known as migrating myoelectric complex, migratory motor complex, migratory myoelectric complex and MMC, is a cyclic, recurring motility pattern that occurs in the stomach and small bowel during fasting; it is interrupted by feeding. [1] A pattern of electrical activity is also observed in the gastrointestinal tract in a regular cycle during this interdigestive period.

Contents

MMC was discovered and characterized in fasting dogs in 1969 by Dr. Joseph H. Szurszewski at the Mayo Clinic. [2] He also showed that this activity stops upon eating a meal, and suggested that it induces a motor activity that acts as an "interdigestive housekeeper" in the small intestine. [2] These motor complexes trigger peristaltic waves, which facilitate transportation of indigestible substances such as bone, fiber, and foreign bodies from the stomach, through the small intestine, past the ileocecal sphincter, and into the colon. MMC activity varies widely across individuals and within an individual when measured on different days. The MMC occurs every 90–230 minutes during the interdigestive phase (i.e., between meals) and is responsible for the rumbling experienced when hungry. [3] [4] It also serves to transport bacteria from the small intestine to the large intestine and to inhibit the migration of colonic bacteria into the terminal ileum; an impairment to the MMC typically results in small intestinal bacterial overgrowth. [5]

Phases

The MMC originates mostly in the stomach—although ~25% will arise from the duodenum or proximal jejunum—and can travel to the distal end of the ileum. [6] They consist of four distinct phases:

Regulation

Movements of the small bowel are believed to be controlled by the central and enteric nervous systems, intestinal muscles, and numerous peptides and hormones. For example, the MMC is thought to be initiated by motilin, and it does not directly depend on extrinsic nerves. [7] Additionally, gastrin, insulin, cholecystokinin, glucagon, and secretin have been reported to disrupt the MMC.

Eating interrupts the MMC. For example, one study found that a continental breakfast of 450 Kcal causes the MMC to disappear for 213 ± 48 minutes. [8] The number of calories and nature of food determine the length of the disruption with fats causing a longer disruption than carbohydrates which in turn cause a longer disruption than protein. [9]

Most of the cleaning waves in the MMC happen at night while we are asleep. For many people this will be sufficient to help maintain a healthy, balanced environment in the digestive tract. For others, it may be beneficial to space out food intake to allow for a couple cleaning waves to occur between meals throughout the day as well. [10]

Impairment

Autoimmunity following infection by a pathogen producing CdtB, such as C. jejuni , may be the leading cause of MMC impairment. [11] Narcotics are also known to impair the MMC. [12] Stress has been shown to reduce MMC activity as well. [13]

Patients with SIBO and IBS have on average a third as many MMC phase III events with those events being roughly 30% shorter on average. [14]

Therapeutic stimuli

Drugs used to enhance gastrointestinal motility are generally referred to as prokinetics. Serotonin induces phase III of the MMC, and so serotonin receptor agonists are commonly administered as prokinetics. [15] Motilin administration causes phase III contractions, and so motilin agonists are another common prokinetic. [16]

Eradication of bacterial overgrowth has been shown to partially restore MMC activity. [14]

An elemental diet has been hypothesized to partially restore MMC function. [17]

Related Research Articles

<span class="mw-page-title-main">Gastrointestinal tract</span> Organ system within humans and other animals

The gastrointestinal tract is the tract or passageway of the digestive system that leads from the mouth to the anus. The GI tract contains all the major organs of the digestive system, in humans and other animals, including the esophagus, stomach, and intestines. Food taken in through the mouth is digested to extract nutrients and absorb energy, and the waste expelled at the anus as faeces. Gastrointestinal is an adjective meaning of or pertaining to the stomach and intestines.

<span class="mw-page-title-main">Peristalsis</span> Radially symmetrical contraction and relaxation of muscles

Peristalsis is a type of intestinal motility, characterized by radially symmetrical contraction and relaxation of muscles that propagate in a wave down a tube, in an anterograde direction. Peristalsis is progression of coordinated contraction of involuntary circular muscles, which is preceded by a simultaneous contraction of the longitudinal muscle and relaxation of the circular muscle in the lining of the gut.

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.

<span class="mw-page-title-main">Enteric nervous system</span> Vital system controlling the gastrointestinal tract

The enteric nervous system (ENS) or intrinsic nervous system is one of the three main divisions of the autonomic nervous system (ANS), the other being the sympathetic (SNS) and parasympathetic nervous system (PSNS), and consists of a mesh-like system of neurons that governs the function of the gastrointestinal tract. It is capable of acting independently of the SNS and PSNS, although it may be influenced by them. The ENS is nicknamed the "second brain". It is derived from neural crest cells.

<span class="mw-page-title-main">Irritable bowel syndrome</span> Functional gastrointestinal disorder

Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder characterized by a group of symptoms that commonly include abdominal pain, abdominal bloating and changes in the consistency of bowel movements. These symptoms may occur over a long time, sometimes for years. IBS can negatively affect quality of life and may result in missed school or work or reduced productivity at work. Disorders such as anxiety, major depression, and chronic fatigue syndrome are common among people with IBS.

<span class="mw-page-title-main">Myenteric plexus</span> Part of the enteric nervous system

The myenteric plexus provides motor innervation to both layers of the muscular layer of the gut, having both parasympathetic and sympathetic input, whereas the submucous plexus provides secretomotor innervation to the mucosa nearest the lumen of the gut.

<span class="mw-page-title-main">Small intestinal bacterial overgrowth</span> Medical condition

Small intestinal bacterial overgrowth (SIBO), also termed bacterial overgrowth, or small bowel bacterial overgrowth syndrome (SBBOS), is a disorder of excessive bacterial growth in the small intestine. Unlike the colon, which is rich with bacteria, the small bowel usually has fewer than 100,000 organisms per millilitre. Patients with bacterial overgrowth typically develop symptoms which may include nausea, bloating, vomiting, diarrhea, malnutrition, weight loss, and malabsorption by various mechanisms.

<span class="mw-page-title-main">Short bowel syndrome</span> Medical condition

Short bowel syndrome is a rare malabsorption disorder caused by a lack of functional small intestine. The primary symptom is diarrhea, which can result in dehydration, malnutrition, and weight loss. Other symptoms may include bloating, heartburn, feeling tired, lactose intolerance, and foul-smelling stool. Complications can include anemia and kidney stones.

<span class="mw-page-title-main">Motilin</span>

Motilin is a 22-amino acid polypeptide hormone in the motilin family that, in humans, is encoded by the MLN gene.

An electrogastrogram (EGG) is a computer generated graphic produced by electrogastrography, which detects, analyzes and records the myoelectrical signal generated by the movement of the smooth muscle of the stomach, intestines and other smooth muscle containing organs. An electrogastroenterogram or electroviscerogram is a similar display of the recording of myoelectrical activity of gastrointestinal or other organs which are able to generate myoelectrical activity.

<span class="mw-page-title-main">Abdominal distension</span> Physical symptom

Abdominal distension occurs when substances, such as air (gas) or fluid, accumulate in the abdomen causing its expansion. It is typically a symptom of an underlying disease or dysfunction in the body, rather than an illness in its own right. People with this condition often describe it as "feeling bloated". Affected people often experience a sensation of fullness, abdominal pressure, and sometimes nausea, pain, or cramping. In the most extreme cases, upward pressure on the diaphragm and lungs can also cause shortness of breath. Through a variety of causes, bloating is most commonly due to buildup of gas in the stomach, small intestine, or colon. The pressure sensation is often relieved, or at least lessened, by belching or flatulence. Medications that settle gas in the stomach and intestines are also commonly used to treat the discomfort and lessen the abdominal distension.

<span class="mw-page-title-main">Blind loop syndrome</span> Medical condition

Blind loop syndrome, also known as stagnant loop syndrome, is a state that occurs when the normal bacterial flora of the small intestine proliferates to numbers that cause significant derangement to the normal physiological processes of digestion and absorption. In some cases of blind loop syndrome, overgrowth of pathogenic non-commensal bacteria has also been noted. It has long been understood that from birth, and throughout life, large amounts of bacteria reside symbiotically within animal gastrointestinal tracts such as the human gastrointestinal tract. The understanding of this gut flora has even led to novel treatments for bowel irregularity that utilize so called "probiotics" or good bacteria that aid in normal digestion. The problem of blind loop syndrome arises when the bacterial colonies residing in the upper gastrointestinal tract begin to grow out of control or are altered in their makeup thereby creating a burden on the normal physiological processes occurring in the small intestine. This results in problems, among others, of: vitamin B12 deficiency, fat malabsorption and steatorrhea, fat-soluble vitamin deficiencies and intestinal wall injury.

A hydrogen breath test is used as a diagnostic tool for small intestine bacterial overgrowth and carbohydrate malabsorption, such as lactose, fructose, and sorbitol malabsorption.

<span class="mw-page-title-main">Rifaximin</span> Antibiotic medication

Rifaximin, is a non-absorbable, broad spectrum antibiotic mainly used to treat travelers' diarrhea. It is based on the rifamycin antibiotics family. Since its approval in Italy in 1987, it has been licensed in over more than 30 countries for the treatment of a variety of gastrointestinal diseases like irritable bowel syndrome, and hepatic encephalopathy. It acts by inhibiting RNA synthesis in susceptible bacteria by binding to the RNA polymerase enzyme. This binding blocks translocation, which stops transcription. It is marketed under the brand name Xifaxan by Salix Pharmaceuticals.

The gastrocolic reflex or gastrocolic response is a physiological reflex that controls the motility, or peristalsis, of the gastrointestinal tract following a meal. It involves an increase in motility of the colon consisting primarily of giant migrating contractions, in response to stretch in the stomach following ingestion and byproducts of digestion entering the small intestine. The reflex propels existing intestinal contents through the digestive system helps make way for ingested food, and is responsible for the urge to defecate following a meal.

Gastrointestinal physiology is the branch of human physiology that addresses the physical function of the gastrointestinal (GI) tract. The function of the GI tract is to process ingested food by mechanical and chemical means, extract nutrients and excrete waste products. The GI tract is composed of the alimentary canal, that runs from the mouth to the anus, as well as the associated glands, chemicals, hormones, and enzymes that assist in digestion. The major processes that occur in the GI tract are: motility, secretion, regulation, digestion and circulation. The proper function and coordination of these processes are vital for maintaining good health by providing for the effective digestion and uptake of nutrients.

<span class="mw-page-title-main">Motilin receptor</span> Protein-coding gene in the species Homo sapiens

Motilin receptor is a G protein-coupled receptor that binds motilin. It was first cloned in 1999 by Merck Laboratories. and scientists have since been searching for compounds to modify its behavior.

<span class="mw-page-title-main">Gastroparesis</span> Medical condition

Gastroparesis, also called delayed gastric emptying, is a medical disorder consisting of weak muscular contractions (peristalsis) of the stomach, resulting in food and liquid remaining in the stomach for a prolonged period of time. Stomach contents thus exit more slowly into the duodenum of the digestive tract. This can result in irregular absorption of nutrients, inadequate nutrition, and poor glycemic control. The opposite of this, where stomach contents exit quickly into the duodenum, is called dumping syndrome.

<span class="mw-page-title-main">Mosapride</span> Chemical compound

Mosapride is a gastroprokinetic agent that acts as a selective 5HT4 agonist. The major active metabolite of mosapride, known as M1, additionally acts as a 5HT3 antagonist, which accelerates gastric emptying throughout the whole of the gastrointestinal tract in humans, and is used for the treatment of gastritis, gastroesophageal reflux disease, functional dyspepsia and irritable bowel syndrome. It is recommended to be taken on an empty stomach (i.e. at least one hour before food or two hours after food).

A prokinetic agent is a type of small peptide drug which enhances gastrointestinal motility by increasing the frequency or strength of contractions, but without disrupting their rhythm. They are used to treat certain gastrointestinal symptoms, including abdominal discomfort, bloating, constipation, heart burn, nausea, and vomiting; and certain gastrointestinal disorders, including irritable bowel syndrome, gastritis, gastroparesis, and functional dyspepsia.

References

  1. ↑ Deloose E, Janssen P, Depoortere I, Tack J. The migrating motor complex: control mechanisms and its role in health and disease. Nat Rev Gastroenterol Hepatol. 2012;9(5):271-285. Published 2012 Mar 27. doi:10.1038/nrgastro.2012.57
  2. 1 2 Szurszewski, Joseph H. (1969-12-01). "A migrating electric complex of canine small intestine". American Journal of Physiology. Legacy Content. 217 (6): 1757–1763. doi:10.1152/ajplegacy.1969.217.6.1757. ISSN   0002-9513.
  3. ↑ Dooley CP, Di Lorenzo C, Valenzuela JE (May 1992). "Variability of migrating motor complex in humans". Digestive Diseases and Sciences. 37 (5): 723–8. doi:10.1007/BF01296429. PMID   1563314.
  4. ↑ Takahashi T (July 2012). "Mechanism of interdigestive migrating motor complex". Journal of Neurogastroenterology and Motility. 18 (3): 246–57. doi:10.5056/jnm.2012.18.3.246. PMC   3400812 . PMID   22837872.
  5. ↑ Hasler W (2006). Physiology of the Gastrointestinal Tract (Fourth ed.).
  6. 1 2 Boron WF, Boulpaep EL (2012). Medical physiology : a cellular and molecular approach (Updated second ed.). Philadelphia, Pa.: Saunders. ISBN   978-1-4377-1753-2.
  7. ↑ Poitras P, Peeters TL (February 2008). "Motilin". Current Opinion in Endocrinology, Diabetes and Obesity. 15 (1): 54–7. doi:10.1097/MED.0b013e3282f370af. PMID   18185063.
  8. ↑ Vantrappen G, Janssens J, Hellemans J, Ghoos Y (June 1977). "The interdigestive motor complex of normal subjects and patients with bacterial overgrowth of the small intestine". The Journal of Clinical Investigation. 59 (6): 1158–66. doi:10.1172/JCI108740. PMC   372329 . PMID   864008.
  9. ↑ Vantrappen G, Janssens J, Peeters TL (November 1981). "The migrating motor complex". The Medical Clinics of North America. 65 (6): 1311–29. doi:10.1016/S0025-7125(16)31474-2. PMID   7035768.
  10. ↑ "Bloating, Gut Health, and the Migrating Motor Complex". Synergy Nutrition. Retrieved 2022-07-19.
  11. ↑ Pimentel M, Morales W, Pokkunuri V, Brikos C, Kim SM, Kim SE, et al. (May 2015). "Autoimmunity Links Vinculin to the Pathophysiology of Chronic Functional Bowel Changes Following Campylobacter jejuni Infection in a Rat Model". Digestive Diseases and Sciences. 60 (5): 1195–205. doi:10.1007/s10620-014-3435-5. PMID   25424202.
  12. ↑ Kueppers PM, Miller TA, Chen CY, Smith GS, Rodriguez LF, Moody FG (March 1993). "Effect of total parenteral nutrition plus morphine on bacterial translocation in rats". Annals of Surgery. 217 (3): 286–92. doi:10.1097/00000658-199303000-00011. PMC   1242782 . PMID   8452407.
  13. ↑ Kumar D, Wingate DL (November 1985). "The irritable bowel syndrome: a paroxysmal motor disorder". Lancet. 2 (8462): 973–7. doi:10.1016/S0140-6736(85)90525-2. PMID   2865504.
  14. 1 2 Pimentel M, Soffer EE, Chow EJ, Kong Y, Lin HC (December 2002). "Lower frequency of MMC is found in IBS subjects with abnormal lactulose breath test, suggesting bacterial overgrowth". Digestive Diseases and Sciences. 47 (12): 2639–43. doi:10.1023/A:1021039032413. PMID   12498278.
  15. ↑ Lördal M, Hellström PM (1998-04-15). "Serotonin induces phase III of the MMC, VIA 5-HT3-receptors dependent on cholinergic mechanisms in the small intestine". Gastroenterology. 114: A795. doi: 10.1016/S0016-5085(98)83246-0 .
  16. ↑ Janssens J, Vantrappen G, Peeters TL (August 1983). "The activity front of the migrating motor complex of the human stomach but not of the small intestine is motilin-dependent". Regulatory Peptides. 6 (4): 363–9. doi:10.1016/0167-0115(83)90265-3. PMID   6635258.
  17. ↑ Pimentel M, Constantino T, Kong Y, Bajwa M, Rezaei A, Park S (January 2004). "A 14-day elemental diet is highly effective in normalizing the lactulose breath test". Digestive Diseases and Sciences. 49 (1): 73–7. doi:10.1023/B:DDAS.0000011605.43979.e1. PMID   14992438.
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