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Associations between IL ‐1 RA polymorphisms and small intestinal bacterial overgrowth among patients with irritable bowel syndrome from India
Author(s) -
Srivastava D.,
Ghoshal U.,
Mittal R. D.,
Ghoshal U. C.
Publication year - 2014
Publication title -
neurogastroenterology and motility
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.489
H-Index - 105
eISSN - 1365-2982
pISSN - 1350-1925
DOI - 10.1111/nmo.12399
Subject(s) - irritable bowel syndrome , gastroenterology , small intestinal bacterial overgrowth , medicine , bloating , genotype , diarrhea , biology , gene , biochemistry
Background Low‐grade inflammation (controlled by pro and anti‐inflammatory molecules), induced by gut microbes in patients with small intestinal bacterial overgrowth ( SIBO ), may be associated with irritable bowel syndrome ( IBS ). Polymorphisms of IL ‐ RA gene (anti‐inflammatory) was evaluated in IBS and healthy subjects ( HS ); small intestinal mucosal IL ‐1 α and β levels (pro‐inflammatory) in relation to the presence of SIBO were evaluated in a subset of patients. Methods Two hundred and twenty‐one IBS patients and 273 age‐ and gender‐matched HS were included. Exactly 209 of 221 patients (Rome III) and 273 HS were genotyped (PCR) for IL‐1RA polymorphism. Mucosal IL‐1 α and β levels (pg/mg of biopsy) were estimated (ELISA) in 82/221 patients with and without SIBO (≥10 5 CFU/mL upper gut aspirate bacteria). Key Results Genotype 1/1 ( IL ‐1 RA over‐producer) was less frequent among patients than controls ( p = 0.007); genotypes 1/3 ( p = 0.012, OR = 3.301, 95% CI = 1.31–8.35) and 2/3 (both under‐producers; p = 0.009, OR = 7.703, 95% CI = 1.66–35.82) were commoner among IBS . Fifteen of 82 (18.3%) patients had SIBO . Levels of IL ‐1 α and β were higher among patients with SIBO than without ( IL ‐1 α : 35.4 [20.1–66.8] vs 25.5 [4.2–65.3], p < 0.001; IL ‐1 β : 206.8 [133.5–365.9] vs 93.1 [25.5–197.7], p < 0.001) and those with bloating than without ( p = 0.012; p = 0.015). IL ‐1 β was higher among patients with Bristol stool type 6 than those with type 1–2 ( p = 0.002) and type 3–5 ( p = 0.007). Conclusions & Inferences Polymorphisms 1/1 ( IL ‐1 RA over‐producer) was infrequent and 1/3 and 2/3 (under‐producers) frequent among IBS . Increased IL ‐1 α and β levels were associated with SIBO . Increased IL ‐1 β level was predominantly associated with bloating and loose stools (Bristol type 6).