GI MAP

The GI-MAP™ 2.0
The GI Microbial Assay Plus (GI-MAP™) now includes two new markers, in addition to the original analytes.

Beta-glucuronidase
Beta-glucuronidase is an enzyme produced by cells in the liver, kidney, intestinal epithelium, endocrine, and reproductive organs (1). However, the major producers of beta-glucuronidase are these bacteria: Bacteroides fragilis, Bacteroides vulgatus, Bacteroides uniformis, Clostridium paraputrificum, Clostridium clostridioforme, Clostridium perfringens, Escherichia coli, Eubacterium, Peptostreptococcus, Ruminococcus, and Staphylococcus. It is found in 97% of E.coli strains (2). The enzyme hydrolyzes B-glucuronide to make glucuronic acid and an aglycone, such as imine, thiol, or alcohol. Glucuronidation by way of beta-glucuronidase is a major route of detoxification in the human body (2). However, this enzyme can also convert pro-carcinogens to carcinogenic compounds (1).

High levels of faecal beta-glucuronidase can indicate unfavorable changes in the colon. When the enzyme is elevated in plasma, there is an increased risk of hormone-sensitive cancers, such as those of the breast or prostate (1). Deconjugation of a variety of toxins, carcinogens, hormones and drugs in the gut permits their reabsorption via enterohepatic recirculation, producing higher than desired blood levels of these potentially harm­ful compounds. Evidence of increased enzymatic activity of intestinal microorganisms may suggest increased risk of digestive tract cancer (3). Patients with diagnosed tumors of the large intestine had high activity of B-glucuronidase (3).  

Toxins stimulate B-glucuronidase activity and dietary red meat and protein increases the enzyme. Antibiotics increase B-glucuronidase levels. A low-calorie, vegetarian diet can reduce faecal B-glucuronidase levels (1).

Evaluating B-glucuronidase may be of interest to clinicians interested in evaluating substances that require deconjugation of glucuronide molecules, such as hormones, vitamin D, toxins, and phytonutrients. 

Interpretation: Abnormally high levels of this biomarker warrant further investi­gation; abnormally low levels may diminish the bioavailability of many phytonutrients.

Further evaluation of patients with elevated faecal B-glucuroni­dase includes consideration of exposure to and intake of toxins, hormones, and drugs.

For patients with elevated faecal B-glucuronidase, the following may be helpful:

  • Calcium-D-glucarate
  • Milk thistle
  • Probiotics (Lactobacilli and Bifidobacteria)
  • Increased consumption of vegetables and insoluble fiber

B-glucuronidase may be lower following antibiotic administration, which may reduce B-glucuronidase activity due to reduction of gut bacteria (4-7)

Steatocrit
Steatocrit has been used widely since 1981 to detect steatorrhea in patients with pancreatic insufficiency and small intestinal malabsorption (8). It is a simple test that uses centrifugation to separate the solid, aqueous, and lipid layers of the stool. The lipid layer is measured in the steatocrit and this makes up the total faecal fat (8). Acidification of the stool dramatically improved the performance of this method. The acid steatocrit method has been shown to correlate well with 24-hour and 72-hour faecal fats; therefore, it is modulated by recent diet (9, 10).

The GI-MAP™ 2.0 also now measures calprotectin instead of lactoferrin.


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Dr Dan Kalish GI-MAP Quote

References

1. Mroczynska M, Galecka M, Szachta P, Kamoda D, Libudzisz Z, Roszak D. Polish journal of microbiology / Polskie Towarzystwo Mikrobiologow = The Polish Society of Microbiologists. 2013;62:319-325.

2. Li Y, Zhang X, Wang L, Zhou Y, Hassan JS, Li M. Int J Clin Exp Med. 2015;8:5310-5316.

3. Mroczynska M, Libudzisz Z. Polish journal of microbiology / Polskie Towarzystwo Mikrobiologow = The Polish Society of Microbiologists. 2010;59:265-269.

4. Kehrer DF, Sparreboom A, Verweij J, et al. Modulation of irinotecaninduced diarrhea by cotreatment with neomycin in cancer patients. Clinical cancer research: an official journal of the American Association for Cancer Research. May 2001;7(5):1136-1141.

5. Gagniere J, Raisch J, Veziant J, et al. Gut microbiota imbalance and colorectal cancer. World journal of gastroenterology : WJG. Jan 14 2016;22(2):501-518.

6. Zhanel GG, Siemens S, Slayter K, Mandell L. Antibiotic and oral contraceptive drug interactions: Is there a need for concern? The Canadian journal of infectious diseases = Journal canadien des maladies infectieuses. Nov 1999;10(6):429-433.

7. Koning CJ, Jonkers DM, Stobberingh EE, Mulder L, Rombouts FM, Stockbrugger RW. The effect of a multispecies probiotic on the intestinal microbiota and bowel movements in healthy volunteers taking the antibiotic amoxycillin. The American journal of Gastroenterology. Jan 2008;103(1):178-189.

8. Ramakrishna BS. Indian journal of gastroenterology : official journal of the Indian Society of Gastroenterology. 2009;28:195-197.

9. Amann ST, Josephson SA, Toskes PP. The American journal of gastroenterology. 1997;92:2280-2284.

10. Bijoor AR, Geetha S, Venkatesh T. Indian J Clin Biochem. 2004;19:20-22.