Lactose intolerance pathophysiology
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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Mahda Alihashemi M.D. [2]
Overview
The exact pathogenesis of [disease name] is not fully understood.
OR
It is thought that [disease name] is the result of / is mediated by / is produced by / is caused by either [hypothesis 1], [hypothesis 2], or [hypothesis 3].
OR
[Pathogen name] is usually transmitted via the [transmission route] route to the human host.
OR
Following transmission/ingestion, the [pathogen] uses the [entry site] to invade the [cell name] cell.
OR
[Disease or malignancy name] arises from [cell name]s, which are [cell type] cells that are normally involved in [function of cells].
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The progression to [disease name] usually involves the [molecular pathway].
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The pathophysiology of [disease/malignancy] depends on the histological subtype.
Pathophysiology
Pathogenesis
- Lactose is a disaccharide of glucose and galactose in ruminant and human milk.
- It is thought that lactose intolerance is the result of lactose malabsorption that it is caused by low level of small intestinal lactase ( lactase-phlorizin hydrolase, or LPH)[1]
- The most important causes of low level of small intestinal lactase are:
- Lactose is metabolized by intestinal lactase to galactose and glucose in villous enterocytes and then are uptaked by Na+/glucose cotransporter (SGLT1). [2][3]
- In colon, unabsorbed lactose is converted to hydrogen gas and short chain fatty acids such as acetate, butyrate and propionate by intestinal bacteria and creates symtoms of lactose intolerance.
- Milk drinkers has greater lactase activity compare with non-drinkers [4]
Genetics
- Lactose intolerance is transmitted in an autosomal recessive pattern.[5]
- Persistence of intestinal lactase until adulthood is inherited as an autosomal dominant characteristic[6]
- Gene involved in the pathogenesis of lactose intolerance include polymorphism of the MCM6 ( minichromosome maintenance complex component 6) gene located upstream from the gene lactase-phlorizin hydrolase (LPH) on the long arm (q) of chromosome 2 in region 21(2q21). Lactase persistence is strongly related with presence of the T allele of the single nucleotide polymorphisms (SNP ) located at -13.9 kb upstream of the lactase gene. This allele regulates lactase mRNA.[7][8]
- Acquired primary lactase deficiency is associated with a CC genotype at -13.9 kb and lactase persistence is related to TT genotype[9]
Gross Pathology
- On gross pathology, there are no characteristic findings of lactose intoelrance.
Microscopic Pathology
- On microscopic histopathological analysis, there are no characteristic findings of lactose intolerance.
References
- ↑ Silanikove N, Leitner G, Merin U (2015). "The Interrelationships between Lactose Intolerance and the Modern Dairy Industry: Global Perspectives in Evolutional and Historical Backgrounds". Nutrients. 7 (9): 7312–31. doi:10.3390/nu7095340. PMC 4586535. PMID 26404364.
- ↑ Maiuri L, Raia V, Potter J, Swallow D, Ho MW, Fiocca R, Finzi G, Cornaggia M, Capella C, Quaroni A (1991). "Mosaic pattern of lactase expression by villous enterocytes in human adult-type hypolactasia". Gastroenterology. 100 (2): 359–69. PMID 1702075.
- ↑ Martín MG, Turk E, Lostao MP, Kerner C, Wright EM (1996). "Defects in Na+/glucose cotransporter (SGLT1) trafficking and function cause glucose-galactose malabsorption". Nat. Genet. 12 (2): 216–20. doi:10.1038/ng0296-216. PMID 8563765.
- ↑ Yoshida Y, Sasaki G, Goto S, Yanagiya S, Takashina K (1975). "Studies on the etiology of milk intolerance in Japanese adults". Gastroenterol. Jpn. 10 (1): 29–34. PMID 1234085.
- ↑ Enattah NS, Sahi T, Savilahti E, Terwilliger JD, Peltonen L, Järvelä I (2002). "Identification of a variant associated with adult-type hypolactasia". Nat. Genet. 30 (2): 233–7. doi:10.1038/ng826. PMID 11788828.
- ↑ Scrimshaw NS, Murray EB (1988). "The acceptability of milk and milk products in populations with a high prevalence of lactose intolerance". Am. J. Clin. Nutr. 48 (4 Suppl): 1079–159. PMID 3140651.
- ↑ Kuokkanen M, Enattah NS, Oksanen A, Savilahti E, Orpana A, Järvelä I (2003). "Transcriptional regulation of the lactase-phlorizin hydrolase gene by polymorphisms associated with adult-type hypolactasia". Gut. 52 (5): 647–52. PMC 1773659. PMID 12692047.
- ↑ Buzás GM (2015). "[Lactose intolerance: past and present. Part 1]". Orv Hetil (in Hungarian). 156 (38): 1532–9. doi:10.1556/650.2015.30261. PMID 26550699.
- ↑ Rasinperä H, Savilahti E, Enattah NS, Kuokkanen M, Tötterman N, Lindahl H, Järvelä I, Kolho KL (2004). "A genetic test which can be used to diagnose adult-type hypolactasia in children". Gut. 53 (11): 1571–6. doi:10.1136/gut.2004.040048. PMC 1774274. PMID 15479673.