Assessment of Serum sTREM-1 as a Marker of Subclinical Inflammation in Diarrhea-Predominant Patients with Irritable Bowel Syndrome
Irritable bowel disease (IBS) is viewed upon as a functional disorder of subclinical inflammatory changes in recent years, and there is no reliable biomarker. Triggering receptor expressed on myeloid cells 1 (TREM-1), also produced in a soluble form (sTREM-1), is involved in the activation of inflammatory cascades of intracellular events and may play a role in pathogenesis of IBS.
To investigate whether serum sTREM-1 level can be used as a marker of subclinical inflammation in D-IBS.
Abdominal pain was quantified by a validated questionnaire. Expression level of TREM-1 in colonic mucosa as well as sTREM-1 level in serum was also detected. Furthermore, we investigated the involvement of TREM-1-associated macrophage activation in IBS-like visceral hypersensitivity.
No evidence for obvious inflammation was found in D-IBS patients. Serum sTREM-1 level in D-IBS patients was significantly higher than that in HCs, which was also significantly correlated with abdominal pain scores. We showed a marked increase in the proportion of TREM-1-expressing macrophages in D-IBS, which was significantly correlated with abdominal pain scores. Functionally, gadolinium chloride (GdCl3), a macrophage selective inhibitor, or LP17, the TREM-1-specific peptide, significantly suppressed the visceral hypersensitivity in trinitrobenzene sulfonic acid (TNBS)-treated mice with IBS-like visceral hypersensitivity.
Serum sTREM-1 level is significantly higher in D-IBS patients and positively correlates with abdominal pain, which may be initiated by TREM-1-associated macrophage activation, indicating the existence of subclinical inflammation in D-IBS. Therefore, serum sTREM-1 is a potential marker of subclinical inflammation in D-IBS.
KeywordsDiarrhea-predominant irritable bowel disease Soluble triggering receptor expressed on myeloid cells 1 Subclinical inflammation Macrophage activation Abdominal pain
This research was supported by the National Natural Science Foundations of China (No. 81500425), the Shandong Provincial Natural Science Foundation, China (No. ZR2014HL018), and the Project of Medical and Health Technology Development Program in Shandong Province (No. 2015WS0370). The authors appreciate the considerable assistance from the Key Laboratory of Cardiovascular Remodeling and Function Research in the Qilu Hospital of Shandong University and the Central Laboratory in Linyi People’s Hospital of Shandong University.
Compliance with ethical standards
Conflict of interest
There is no financial conflict of interest to declare.
- 1.Hughes PA, Harrington AM, Castro J, et al. Sensory neuro-immune interactions differ between irritable bowel syndrome subtypes. Gut. 2012;61:1456–1465.Google Scholar
- 21.Saurer L, Rihs S, Birrer M, Saxer-Seculic N, Radsak M, Mueller C. Elevated levels of serum-soluble triggering receptor expressed on myeloid cells-1 in patients with IBD do not correlate with intestinal TREM-1 mRNA expression and endoscopic disease activity. J Crohns Colitis. 2012;6:913–923.CrossRefPubMedGoogle Scholar