Skip to content

Increased Intestinal Permeability (Leaky Gut)

Close-up Slice of a Small Intestinal Villus Showing How Enterocytes Appear Tightly Lining the Entire Outside Surface Of A Villus. Courtesy Cleo Libonati

What Is Increased Intestinal Permeability?

[dropcap]I[/dropcap]ncreased intestinal permeability is characterized by dysfunctional intestinal permeability (leakiness) allowing for the penetration of harmful entities from the gut into the bloodstream such as undigested proteins and microbes. The popular name is “leaky gut.”

Q: Why does intestinal permeability increase?

A: Intestinal permeability is an essential function of the small intestinal mucosal lining by which wanted substances such as properly digested foodstuffs are allowed to permeate through the lining to enter the body via the bloodstream and lymphatics. At the same time unwanted substances are kept out.

The mucosal lining is one cell thick and makes up the surface between the digested foodstuffs inside the hollow of the intestine and the underlying tissues.

The mucosal lining is covered by millions of microscopic finger-like structures called villi that project toward the inside of the intestine giving the appearance of a shag rug.

Each one, called a villus, contains a capillary bringing blood to absorb nutrients, a vein to take away nutrients, and a lacteal to absorb and take away digested fat. Its wall is made up of a single layer of tightly connecting cells, called enterocytes.

This single layer of cells separates the contents of our small intestine from the lamina propria (underlying tissues of the small intestine) and the rest of our body. Breaching of this single layer of cells by leakiness can expose lymphocytes (immune cells) located in the lamina propria to a myriad of microorganisms and food antigens, leading to immune reactions.1

To protect the body from unwanted substances, a gatekeeping barrier system operates to regulate the passage of nutrients, or permeation, through the surface mucosal lining. This system acts to seal the inside body from the gut.

The integrity of intestinal permeability is determined by interactions among several barrier components including the unstirred water layer, mucosal surface hydrophobicity, the surface mucous coat, and cell factors (especially tight junctions).

Tight junctions hold cells tightly together side-by-side to prevent unwanted substances from passing through the lining. Tight junctions are complex structures comprising over 50 proteins, such as the claudin proteins which are considered to be the structural backbone of tight junctions.

Tight junctions include a series of special proteins forming fibrils (springy like proteins) that cross the plasma membrane and interact with proteins in the adjoining cells. Tight junctions are regulated by the protein zonulin.2

If zonulin deregulates from the action of substances such as gliadin (gluten in wheat) and bacteria, the tight junction barrier fails which results in increased intestinal permeability. Dysfunction of the barrier system allows unwanted substances to enter the body where they are damaging to many tissues.

Tight junction dysfunction has been shown to be a part of certain autoimmune diseases such as celiac disease, type I diabetes mellitus, multiple sclerosis, and rheumatoid arthritis. Other diseases associated are cancer, allergies, and infections.3

Important gastrointestinal infections that cause leaky gut include rotavirus, parasites, pathogenic bacteria (escherichia coli, clostridium difficile), and mycotoxins produced by fungi found in stored grain and dried fruit.4

Fortunately, the presence of some commensal (friendly intestinal bacteria) and probiotic strains leads to an increase in tight junctions  proteins at the cell boundaries and in some cases prevents or reverses the adverse effects of pathogens, food and stress. Various dietary components are also known to regulate epithelial permeability by modifying expression and localization of  tight junctions proteins.2

What Is Increased Intestinal Permeability In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Fahardi A, Banan A, Fields J, Keshavarzian A. Intestinal barrier: an interface between health and disease. Journal of Gastroenterology and Hepatology. 2003; 18: 479-497. [↩]
  2. Ulluwishewa D, Anderson RC, McNabb WC, Moughan PJ, Wells JM, Roy NC. Regulation of tight junction permeability by intestinal bacteria and dietary components. J Nutr. 2011 May;141(5):769-76. doi: 10.3945/jn.110.135657. [↩] [↩]
  3. Fasano A. Zonulin and Its Regulation of Intestinal Barrier Function: The Biological Door to Inflammation, Autoimmunity, and Cancer. Physiological Reviews. January 2011Vol. 91no. 151-175DOI: 10.1152/physrev.00003.2008 [↩]
  4. Farhadi A, Banan A, Fields J, Keshavarzian A. Intestinal barrier: an interface between health and disease. Journal of Gastroenterology and Hepatology. 2003;18:479-91. [↩]

Candida Albicans Infection

Close-up shows inflammation and yellowish white patches of roof and back of the mouth caused by candidiasis. Uvula is greatly swollen, hanging near the level of the tongue. Courtesy: Wikipedia.
Close-up shows inflammation and infected patches on roof and back of the mouth caused by candidiasis. Uvula is swollen, hanging near the tongue. Courtesy: Wikimedia.

What Is Candida Albicans Infection?

[dropcap]C[/dropcap]andida albicans infection, called candidosis or candidiasis, is an opportunistic invasion of mucous membrane or skin by candida albicans, an endogenous yeast found in 40 to 80% of normal human beings. A former name for this small, budding fungus is monilia albicans.

Opportunistic means that yeast living on mucosal and skin surfaces does not invade (infect) unless these tissues become unhealthy and therefore cannot protect themselves.

Q: How does candida albicans cause infection?

A: Candida albicans lives on the mucosal surfaces and skin in most people without causing infection (colonizes) because of our normal defenses against invasion. In fact, candida albicans is a very effective colonizer of humans. For example, Russell and Lay found that 47% of 1-month-old infants were orally colonized with candida albicans, and 49% were colonized with other fungi.

During growth within the intestinal tract, the organism senses pH (acidity), oxygen, carbon sources, and the presence of surfaces allowing it to optimize gene expression for a particular environment. With these mechanisms for sensing, candida albicans is able to efficiently colonize humans in infancy.1

Candida Infection Of The Esophagus on X-ray. Courtesy Radiology Assistant.nl
Candida Infection Of The Esophagus (White Area) On X-ray. Courtesy Radiology Assistant.nl

Lowered host defenses allow yeast already present on mucosal and skin surfaces to take advantage and can grow rapidly, becoming pathogenic (disease producing) so that infection results.

Infection is characterized by superficial, irregular white patches on mucosal surfaces and possible invasion of the bloodstream by a filamentous form (thread-like structures) that can rapidly develop.

Candida albicans is unique among oral pathogens in its ability to invade cornified layers of stratified squamous epithelium of the tongue, mouth surfaces, hard and soft palate, esophagus, and gut. Stratified squamous epithelium is the tough surface cells that ordinarily protect underlying tissues from damage or invasion by microbes.

Candida albicans is also capable of invading the lungs and causing pneumonia and septicemia, which is the spread of infection into the bloodstream.

Here is a time honored simple do-it-youself test for infection of the mouth or throat: First thing in the morning before brushing your teeth or eating, fill a small see through glass with water then gently spit onto the surface. If after an hour the spit remains on the water surface, it is unlikely you have candida in the mouth. If it grows legs downward, it indicates that yeast is growing. If the spit sinks to the bottom, you have this problem. Yeast in the mouth can quickly travel down the esophagus and into the gut.

Medical diagnosis. Difinitive diagnosis for the oral cavity is made by your clinician by swabbing the areas of your mouth and/or throat and viewing under a microscope for evidence of candida.

Infections of the esophagus and gut require inspection by gastroscopy or endoscopy procedure and the taking of samples to be examined under microscope. This examination also give the opportunity to rule out other problems. Barium swallow can show the extent of infection and any disfiguration of the esophagus that results.

What Is Candida Albicans Infection In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Rosenbach A, Dignard D, Pierce JV, Whiteway M, Kumamoto CA. Adaptations of Candida albicans for growth in the mammalian intestinal tract. Eukaryot Cell. 2010 Jul;9(7):1075-86. doi: 10.1128/EC.00034-10. Epub 2010 Apr 30. [↩]

Gluten Sensitive Enteropathy (Active Celiac Disease)

canstockphoto17997339What Is Gluten Sensitive Enteropathy?

Gluten sensitive enteropathy is active celiac disease characterized by inflammation of the small intestinal mucosa that results from an inherited immunologic intolerance to ingested gluten.

Q: What does the inflammation do to the mucosa in the small intestine?

A: Inflammation is a cell level immune response to gluten that has these effects on the mucosa:

  • Damages the barely visible villi (multitudinous finger-like structures) by causing atrophy or loss.
  • Likely affects the structural support and microcirculation of the villus, leading to collapse of the villus.
  • Elongates the crypts between villi. The thickening of the crypt is not so much a response to loss of surface enterocytes but represents inflammation of the mucosa.1
  • Increases round cells in the lamina propria and surface epithelial cells leaving few, irregular microvilli (brush border) on the surface of villi.
  • Damage is most intense in the duodenum and decreases toward the large intestine.
  • The extent of the damage to the intestine determines the malabsorptive consequences of the disease. Both gastric and small intestinal permeability are disrupted in patients with celiac disease.2
  • Relationship between active celiac disease and intestinal permeability: There is a clear association between degree of mucosal damage and the intestinal-permeability ratio, and a normal ratio generally implies near-normal small intestinal structure. A raised intestinal permeability of the mucosal lining (leaky gut) could predispose to a high absorption of gluten and exacerbate an existing lesion and hence convert a latent to an overt enteropathy.3
  • Relationship between active celiac disease and tight junction proteins: A study of intestinal permeability showed that the expression of all junction proteins of the small intestinal lining (occludin, claudin 3, zonula occludens 1, and E-cadherin) was already decreased in early stage celiac disease when compared with non-celiac controls, showing leaky gut and confirming the above earlier study by Johnston et al. Junction protein expression correlated positively with mucosal villus structure and negatively with the number of intraepithelial lymphocytes (IELs), the intensity of small-intestinal autoantibody deposits, and serum autoantibodies. The expression of claudin 3 showed a negative correlation with diarrheal score.4
  • Relationship between active celiac disease and inflammation. In celiac disease there is an over production of inflammatory interleukin-15 (IL-15) which inhibits the correct removal of damaged intraepithelial lymphocytes caused by the reaction to gluten. Serum levels of IL-15 are directly correlated with the seriousness of tissue damage.5

  • Relationship between active celiac disease and gut microbiota. Results of a study investigating intestinal microbiota (normal bacterial residents) in patients with celiac disease suggest that with lower levels of the genus bifidobacteria, celiac patients have an imbalance in the intestinal microbiota even while on a gluten-free diet. This fact could favor the pathological process of the disorder. The concentration of bifidobacteria per gram of feces was significantly higher in healthy subjects (2.5 ± 1.5 x107 CFU/g) when compared to celiac patients (1.5 ± 0.63 x108 CFU/g).6

  • Relationship between active celiac disease and endoscopy technique. The most severe degree of villous atrophy was detected when distal duodenal biopsy specimens were taken in addition to a duodenal bulb biopsy specimen from either the 9- or 12-o’clock position (96.4% sensitivity; 95% CI, 79.7%-100%). The difference between the 12-o’clock position biopsy and the 3-o’clock position biopsy in detecting the most severe villous atrophy was 92% (24/26 patients) versus 65% (17/26 patients).7
  • Relationship between active celiac disease and diet adherence. Patients with consistent gluten free diet adherence experience symptomatic responses to dietary gluten (SRDG) faster and more severe in comparison to their prior gluten exposure possibly demonstrating an adept immunological response. Anxiety and depression also enhance the speed of symptom onset and co-existing visceral hypersensitivity is a risk factor for severe reactions to dietary gluten.8
  • Relationship between active celiac disease and atrial fibrillation: Patients with celiac disease, verified by intestinal biopsy, are at increased risk of atrial fibrillation. This observation is consistent with previous findings that elevation of inflammatory markers predicts atrial fibrillation.9

How Prevalent Is Gluten Sensitive Enteropathy?

Sources:
  1. Murray JA, the widening spectrum of celiac disease. American Journal of Clinical Nutrition. Mar 1999; 69(3):354-365. [↩]
  2. Murray JA, the widening spectrum of celiac disease. American Journal of Clinical Nutrition. Mar 1999; 69(3):354-365. [↩]
  3. Johnston SD, Smye M, Watson RGP. Intestinal permeability and morphometric recovery in coeliac disease. Lancet. Jul 28, 2001;358(9278):259, 2p. [↩]
  4. Rauhavirta T, Lindfors K, Koskinen O, Laurila K, Kurppa K, Saavalainen P, Mäki M, Collin P, Kaukinen K. Impaired epithelial integrity in the duodenal mucosa in early stages of celiac disease. Transl Res. 2014 Sep;164(3):223-31. doi: 10.1016/j.trsl.2014.02.006 [↩]
  5. Stazi AV, Trinti B. Selenium status and over-expression of interleukin-15 in celiac disease and autoimmune thyroid diseases. Ann Ist Super Sanita. 2010;46(4):389-99.DOI: 10.4415/ANN_10_04_06. [↩]
  6. Golfetto L, de Senna FD, Hermes J, Beserra BT, França Fda S, Martinello F. Lower bifidobacteria counts in adult patients with celiac disease on a gluten-free diet. Arq Gastroenterol. 2014 Apr-Jun;51(2):139-43. [↩]
  7. Kurien M, Evans KE, Hopper AD, Hale MF, Cross SS, Sanders DS. Duodenal bulb biopsies for diagnosing adult celiac disease: is there an optimal biopsy site? Gastrointest Endosc. 2012 Jun;75(6):1190-6. doi: 10.1016/j.gie.2012.02.025. [↩]
  8. Barratt SM, Leeds JS, Sanders DS. Factors influencing the type, timing and severity of symptomatic responses to dietary gluten in patients with biopsy-proven coeliac disease. J Gastrointestin Liver Dis. 2013 Dec;22(4):391-6. [↩]
  9. Emilsson L, Smith JG, West J, Melander O, Ludvigsson JF. Increased risk of atrial fibrillation in patients with coeliac disease: a nationwide cohort study. Eur Heart J. 2011 Oct;32(19):2430-7. doi: 10.1093/eurheartj/ehr167. [↩]

Diarrhea, Chronic

chronic diarrhea gluten celiac disease symptomWhat Is Chronic Diarrhea?

[dropcap]C[/dropcap]hronic diarrhea is an intestinal motility disorder characterized by 1) alteration in stool formation causing loose to fluid movements and quantity of movements with or without abdominal pain and 2) interference with normal carbohydrate salvage by the intestinal microbe population.

The severity of diarrhea is determined by the frequency and quantity of fluid lost.

Q: What is carbohydrate salvage by microbes in the colon?

A: Carbohydrate salvage in the colon is the necessary process whereby billions of microbes normally present in the colon work to breakdown undigestible carbohydrate foodstuffs such as fiber that continually arrive from the small intestine.

The microbial action releases energy to the body that would otherwise be lost with defecation, generates short-chain fatty acids, and stimulates sodium and fluid absorption. In this important process, butyrate and proprionate are produced which nourish the colonocytes (cells that line the colon), and acetate is produced for the liver.

While diarrhea may be a common symptom of small bowel mucosal disease, the consequent malabsorption can lead to substantial malnutrition and nutrient deficiencies. The small intestine, unlike the colon, has been relatively inaccessible, and systematic evaluation is often necessary to identify and treat small intestinal mucosal diseases that lead to diarrhea. All patients with severe diarrhea or diarrhea associated with features suggestive of malabsorption may have a disease of the small intestinal mucosa that requires careful evaluation and targeted management.1

What Is Chronic Diarrhea In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Murray JA1, Rubio-Tapia A. Diarrhoea due to small bowel diseases. Best Pract Res Clin Gastroenterol. 2012 Oct;26(5):581-600. doi: 10.1016/j.bpg.2012.11.013. [↩]

Adenocarcinoma Of Small Intestine (Cancer)

Section of small bowel surgically removed for adenocarcinoma that grew through the wall. By: CDC/ Dr. Edwin P. Ewing, Jr.
Section of small bowel surgically removed for adenocarcinoma that grew through the wall. By: CDC/ Dr. Edwin P. Ewing, Jr.

What Is Adenocarcinoma Of Small Intestine?

[dropcap]A[/dropcap]denocarcinomas are malignant tumors, or cancer, of the small bowel arising out of glandular tissue. They fall in the category of rare neoplasm, comprising only 3% of all gastrointestinal malignancies.

Primary adenocarcinoma is the most common histological (cell) subtype constituting 35–50% of cases.1 

Q: What does adenocarcinoma look like?

A: Adenocarcinoma may manifest as strictures, nodules, excavating masses, or annular lesions.2

What Is Adenocarcinoma Of Small Intestine In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Benhammane H, El M’rabet FZ, Serhouchni KI, El yousfi M, Charif I, Toughray I, et al. Small Bowel Adenocarcinoma Complicating Coeliac Disease: A Report of Three Cases and the Literature Review. Case Rep Oncol Med. 2012; 2012: 935183. Published online 2012 December 1. doi: 10.1155/2012/935183 [↩]
  2. Ramachandran I, Sinha R, Rajesh A, Verma R. Multidetector row CT of small bowel tumors.  Clinical Radiology. 2007; 62:607-614. [↩]

Small Bowel Intussusception

Invagination_Schema[1]What Is Small Bowel Intussusception?

[dropcap]S[/dropcap]mall bowel intussusception is a bowel derangement that is characterized by the slipping of one section of intestine into another, leading to bowel obstruction.

Acute bowel intussusception is a rare manifestation in adults, which mainly involves the small intestine.1

What Is Small Bowel Intussusception In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Grados A, Bernard F, Coquet-Reinier B, Rossi P, Bagneres D, Demoux AL, Marciano S, Frances Y, Granel B. Acute bowel intussusception revealing celiac disease a new case and literature review. Rev Med Interne. 2011 Oct;32(10):628-32. doi: 10.1016/j.revmed.2011.03.334 [↩]

Sucrose Intolerance and Sucrosemia 

Sweet Bon Bons: Courtesy Freepik.
Sugary Bon Bons: Courtesy Freepik.

What Is Sucrose Intolerance And Sucrosemia?

[dropcap]S[/dropcap]ucrose intolerance is the inability to digest sucrose, a widely available sugar, while sucrosemia is the abnormal presence of sucrose in the bloodstream.

Q: Why cannot the body digest sucrose?

A: Sucrose, such as cane or beet sugar, is a double molecule sugar which must first be digested before being absorbed from the gut into the bloodstream. That is, sucrose must be split into its component single molecules of fructose and glucose, which are then properly absorbed.

The inability to properly digest sucrose results directly from low production and activity of sucrase in the small intestine. Sucrase is the specific enzyme that splits or digests sucrose.

Undigested sucrose does not remain idle. Its presence acts osmotically to draw water from the body into the intestine, causing watery diarrhea.

Meanwhile, microbiota (normal bacteria) in the colon eagerly ferment the abnormally present sucrose that arrives from the small intestine. Fermentation generates short-chain fatty acids and hydrogen gas, which results in bloating pain.1

In sucrosemia, sucrose molecules abnormaly pass through an unhealthy small intestinal lining and enter the bloodstream where there presence is abnormal. Sucrose in the blood is filtered out by the kidneys and excreted in urine.

Positive response to a breath hydrogen test (BHT), involving 1 – 3 hours of time post ingestion of sucrose test dose, signifies malabsorption in the small intestine and fermentation in the colon. If BHT is positive before 60 minutes, the result implies bacteria is abnormally present in the small intestine, causing fermentation there. Endoscopy is used to measure sucrase activity in tissue samples.

What Is Sucrose Intolerance And Sucrosemia In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Krause’s Food, Nutrition, & Diet Therapy. 10th Edition. Kathleen Mahan, Sylvia Escott-Stump. 2000. W.B. Saunders Company. [↩]

Food Allergy – IgE and Non IgE

Baby with Allergic Reaction to Peanuts. GFW
Baby with Allergic Reaction to Peanuts. GFW photo.

What Is Food Allergy?

[dropcap]F[/dropcap]ood allergy is an abnormal immune response to food proteins that may damage the small intestinal  lining and produce malabsorption of food. The reaction is usually delayed which makes it difficult to identify the offending food that is causing symptoms.

Q: How does food allergy develop?

A: The gastrointestinal tract serves not only to digest and absorb foodstuffs but also to protect the body from unwanted substances. When allergic food substances are eaten, the immune response that is triggered in the gut produces inflammation with symptoms such as pain, vomiting and loose bowels.

Inflammation causes swelling of the gut lining that can interfere with the passage of nutrients through it to the body which results in malabsorption. Malabsorption deprives the body of nutrients needed for normal function.

Symptoms other than digestive may involve skin rashes, hives, and respiratory difficulties that can be distressing and life-threatening.

What Is Food Allergy In Celiac Disease and/or Gluten Sensitivity?

Anti-tissue Transglutaminase Antibodies (tTG) Present In Blood

Image depicts tissue transglutaminase (tTg).
Image Depicts Tissue Transglutaminase (tTG).

What Are Anti-tissue Transglutaminase Antibodies?

[dropcap]A[/dropcap]nti-tissue transglutaminase antibodies (anti-tTG) are connective tissue autoantibodies and can be detected in blood samples from affected persons who are reacting to gluten in the diet.

Autoantibodies are abnormal because they attack the body’s own tissue, which in the case of these antibodies is tissue transglutaminase 2 (TG2).

Q: What is tissue transglutaminase 2 (TG2)?

A: Tissue transglutaminase 2 (TG2) is an enzyme that appears in many cell locations and is particularly abundant in endothelial cells that line the small intestine. It has been implicated in a variety of cellular processes, such as differentiation, cell death, inflammation, cell migration and wound healing.

The cell appears to adapt the dynamics of this enzyme to meet specific sub-cellular needs or to respond to stress or other stimuli. Substantial evidence indicates that the location of TG2 within cells is critical for the regulation of its various biochemical activities, which subsequently trigger diverse downstream events,1

Although initially studied as an enzyme within cells, TG2 is now known to be secreted also into the extracellular space (between cells) or onto the cell surface.1

Abnormal activation of TG2 or deregulation of its function(s) is involved in a variety of human diseases, such as celiac disease, diabetes, neurodegenerative diseases, multiple sclerosis and rheumatoid arthritis. A role in inflammatory disorders and septic shock has also been shown. Moreover, multiple studies have revealed elevated TG2 expression in many types of cancer cells.1

What Are Anti-tissue Transglutaminase Antibodies In Celiac Disease and/or Gluten Sensitivity?

Sources:
  1. Piacentini M, D’Eletto M, Farrace MG, Rodolfo C, Del Nonno F, Ippolito G, Falasca L. Characterization of distinct sub-cellular location of transglutaminase type II: changes in intracellular distribution in physiological and pathological states. Cell Tissue Res. 2014 Dec;358(3):793-805. doi: 10.1007/s00441-014-1990-x. [↩] [↩] [↩]

Celiac Disease After Childbirth (Puerperium)  

Diarrhea Complicating PuerperiumWhat Is The Puerperium Complicated by Celiac Disease?

[dropcap]C[/dropcap]eliac disease complicating puerperium is an adult manifestation of celiac disease that appears during the 6 weeks after delivery of a baby(ies). It is characterized by severe diarrhea in the newly delivered mother and results in malabsorption.

Ordinarily, celiac disease very rarely manifests during pregnancy or after childbirth possibly due to hormonal and immunological changes.

How Prevalent Is The Puerperium Complicated By Celiac Disease?