Association between iron status and inflammation markers with GDF15 and BMP6 in inflammatory bowel disease: a single center cross-sectional study.

BACKGROUND

Inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), are chronic disorders with relapsing and remitting disease courses. Several clinical indicators and biomarkers have been evaluated for their clinical utility in assessing disease prognosis and monitoring disease activity. This study evaluated the utility of growth differentiation factor-15 (GDF15) and bone morphogenetic protein-6 (BMP6) in inflammatory pathways and iron regulation in IBD.

METHODS

Between September 2015 and March 2016, this single-center, cross-sectional study included 40 CD patients, 29 UC patients, and 70 healthy controls. The disease activity was measured using the Mayo score and the Crohn's Disease Activity Index (CDAI). Serum iron, hematological indices, inflammatory markers, and the novel biomarkers BMP6 and GDF15 as determined by ELISA were evaluated.

RESULTS

Both the CD and UC groups showed significantly lower serum iron (p < 0.001), reduced mean corpuscular hemoglobin concentration, and higher red cell distribution width than the control group. Inflammatory markers, including erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), were elevated in IBD, particularly during active disease, with CRP increasing significantly in active UC compared to remission (p = 0.040). In contrast, BMP6 and GDF15 levels did not differ significantly between the disease groups or activity states. Nonetheless, GDF15 demonstrated moderate positive correlations with serum iron (r = 0.314), hemoglobin (r = 0.320), and mean corpuscular hemoglobin concentration (MCHC) (r = 0.344), suggesting a link to erythropoietic or iron-related processes rather than inflammation.

CONCLUSIONS

Conventional markers reliably confirmed iron deficiency and inflammation in IBD. BMP6 and GDF15 levels did not differ significantly across disease states, indicating limited utility as markers of disease activity. Notably, GDF15 was positively correlated with serum iron, hemoglobin, and MCHC, suggesting its association with iron metabolism rather than active inflammation. Larger longitudinal studies are warranted to validate this potential role.

TRIAL REGISTRATION: Not applicable.