Irritable bowel syndrome immune hypothesis: Part two: the role of cytokines

Abstract

Objective:To review the available evidence on the role of interleukins in the etiopathogenesis of Irritable Bowel Syndrome.Methods: Bibliographic retrieval on PubMed including the MeSH terms "Irritable Bowel Syndrome, "Immune System", "Cytokines" and "Interleukins".Results: Sixteen case-control studies and one randomised controlled trial were retrieved. The blood appears to have a high concentration of pro-inflammatory cytokines (TNF-α, IL-1β, IL-6, IL-8) and lower concentration of IL-10, an anti-inflammatory cytokine, even though the findings are disparate and heterogeneous. As many as 33 genes were found, each with different expressions, and a diminished expression of cytokines in the colon mucosa of patients with IBS, which have not been previously described in any other pathology.Conclusions: In patients with IBS, a clear profile of cytokine levels in the blood does not appear to exist, although an imbalance between them can be observed. Moreover, there are indications that give reason to believe that the different subsets of patients with IBS could present cytokine profiles in different blood. On the other hand, in the intestine, high cytokine secretion levels are not detected, contrary to what would be expected. Further studies are required to substantiate these findings. RESUMENObjetivo: Revisar la evidencia disponible sobre el papel de las interleukinas en la etiopatogenia del Síndrome del Intestino Irritable.Métodos: Recuperación bibliográfica en PubMed, incluyendo los términos MeSH "Irritable Bowel Syndrome, "Immune System", "Cytokines" e "Interleukins".Resultados: Se recuperaron 16 estudios casos-control y un ensayo clínico aleatorizado. A nivel sanguíneo, parece existir una concentración elevada de citokinas proinflamatorias (FNT-α, IL-1β, IL-6, IL-8) y disminuida de la IL-10, una citokina antiinflamatoria, si bien los resultados son dispares y heterogéneos. Se han encontrado hasta 33 genes, cada uno con una expresión diferente, y una expresión disminuida de citokinas en la mucosa del colon de pacientes con SII, que no se ha descrito hasta el momento para ninguna otra patología.Conclusiones: En los pacientes con SII, no parece existir un perfil claro de los niveles de citokinas en sangre, si bien, si parece existir un desequilibrio entre ellas. Asimismo, hay indicios que hacen pensar que los distintos subgrupos de pacientes con SII podrían presentar un perfil de citokinas en sangre diferente. Por otro lado, a nivel intestinal, no se detectan niveles elevados de secreción de citokinas, en contra de lo que cabría esperar. Son necesarios más estudios para confirmar estos hallazgos. Palabras clave: Síndrome del Intestino Irritable. Sistema inmune. Citokinas. Interleukinas. Psiconeuroinmunología. Revisión sistemática. Sebastián Domingo JJ. Irritable bowel syndrome immune hypothesis. Part two: the role of cytokines. Rev Esp Enferm Dig 2010; 102: 711-717. M. ORTIZ-LUCAS ET AL. REV ESP ENFERM DIG (Madrid)

Editorial: Abnormal Immune Regulation and Low-Grade Inflammation in IBS: Does One Size Fit All?

“…Because immunocytes and thus, cytokines are in close proximity with aff erent primary nonadrenergic, non-cholinergic nerves in the gut mucosa, they could infl uence some of the motor and viscerosensory abnormalities, as well as symptoms reported by IBS suff erers ( 12 ). Notwithstanding, a recent systematic review found inconsistent results regarding cytokines in IBS ( 13 ). Patients with IBS had high blood concentrations of proinfl ammatory cytokines and lower levels of the antiinfl ammatory cytokine IL-10, whereas the colonic mucosa had decreased cytokine expression ( 13 ).…”

“…not duplicate these fi ndings in cultures of sigmoid biopsy samples from women with IBS and controls ( 15 ). Because cytokine expression is in part genetically determined, the imbalance in the pro-and anti-infl ammatory cytokines might be the consequence of polymorphisms, although at present, this remains unproven ( 13,16,17 ).…”

“…Notwithstanding, a recent systematic review found inconsistent results regarding cytokines in IBS ( 13 ). Patients with IBS had high blood concentrations of proinfl ammatory cytokines and lower levels of the antiinfl ammatory cytokine IL-10, whereas the colonic mucosa had decreased cytokine expression ( 13 ). Elevated proinfl ammatory cytokines from peripheral blood mononuclear cells in the basal period and aft er stimulation with lipopolysaccharides has been shown in IBS-diarrhea ( 14 ).…”

The Effect of Tong‐Xie‐Yao‐Fang on Intestinal Mucosal Mast Cells in Postinfectious Irritable Bowel Syndrome Rats

“…As a major bioactive molecule and a specific mark of activating degranulation [29], tryptase can act in a way that is similar to the activated mast cells [30] that can secrete inflammatory media TNF- α and IL-1 β . Systemic evaluation of clinical literature indicates that, compared with normal participants, IBS patients have distinctly increased serum TNF- α and IL-1 β levels; particularly, IL-1 β level is notably increased in PI-IBS patients [31]. In addition to remarkably increased IL-1 β level in PI-IBS patients, TNF- α level is also significantly elevated in IBS patients [32].…”

IL-10 and TNF-α polymorphisms in subjects with irritable bowel syndrome in Mexico

“…These polymorphisms could then affect the susceptibility for developing IBS, as well as its phenotypic expressions (IBS-D; constipation-predominant IBS: IBS-C; and alternating/mixed IBS: IBS-A/M), at least in a subgroup of patients in whom immune activation would be a supposed factor. Nevertheless, according to a recent systematic review of the literature, the data on the genetic variants of the cytokines in IBS and controls are inconsistent (17). On the other hand, no studies on polymorphisms in IBS have been conducted in Latin America to date (18).…”