Fecal dipeptidyl peptidase-4 (fDPP-4) level may be used as a noninvasive biomarker of inflammatory bowel disease (IBD) activity, especially in patients with ulcerative colitis (UC), investigators reported in Clinical and Translational Gastroenterology.
The study included 101 patients with IBD — 51 with UC and 50 with Crohn disease (CD) — and 40 healthy controls. Among the patients with UC, 29 were in clinical remission (median age, 45 years; 35% male; median disease duration, 9 years), and 22 had clinical activity (median age, 43 years; 59% male; median disease duration, 5 years).
Of the patients with CD, 23 were in clinical remission (median age, 40 years; 61% male; median disease duration, 11 years), and 27 had clinical activity (median age, 36 years; 48% male; median disease duration, 5 years).
Among the participants with UC, 22 underwent colonoscopy, 8 patients (36%) were in endoscopic remission, and 14 (64%) had endoscopic activity.
The investigators analyzed fDPP-4 levels and correlated them with clinical scores, Mayo endoscopic scores in patients with UC, serum DPP-4, C-reactive protein, and fecal calprotectin. Immunohistochemical staining for DPP-4 in intestinal biopsies was also performed.
The fDPP-4 levels were lower in patients with UC and clinical activity compared with those of remitters (1213 ng/mL; Interquartile Range [IQR], 559-1682 ng/mL vs 7814 ng/mL; IQR, 2555-7985 ng/mL; P <.001) and healthy controls (1213 ng/mL; IQR, 559-1682 ng/mL vs 2842 ng/mL; IQR, 1570-5712 ng/mL; P =.019).
Remitters had higher fDPP-4 levels compared with healthy controls (7814 ng/mL; IQR, 2555-7985 ng/mL vs 2842 ng/mL; IQR,1570-5712 ng/mL; P =.006). Patients with UC and endoscopic activity had lower levels than did remitters (939 ng/mL; IQR, 559-1420ng/mL vs 7544 ng/mL; IQR, 4531-7940 ng/mL; P =.006) and healthy controls (939 ng/mL; IQR, 559-1420 ng/mL vs 2842 ng/mL; IQR,1570-5712 ng/mL; P =.004). Patients with CD and active ileal disease had higher fDPP-4 levels compared with those in remission (7584 ng/mL; IQR, 1464-7816 ng/mL vs 2104 ng/mL; IQR, 630-2676 ng/mL; P =.015).
Receiver operating characteristics (ROC) curve analysis confirmed that among patients with UC, fDPP-4 can discriminate between: (1) healthy controls and patients in clinical remission and with clinical activity, with an area under the curve (AUC) of 0.70 (95% CI, 0.56-0.84; P =.006) and 0.68 (95% CI, 0.53-0.84; P =.019), respectively; (2) healthy controls and patients with endoscopic activity, with an AUC of 0.76 (95% CI, 0.61-0.91; P =.004); (3) patients with clinical activity and remitters, with an AUC of 0.80 (95% CI, 0.68-0.93; P <.001); and (4) patients with endoscopic activity and those in endoscopic remission, with an AUC of 0.84 (95% CI, 0.63-1.00; P =.009).
In addition, ROC curve analysis revealed that among patients with ileal CD, fDPP-4 can discriminate remitters from those with clinical activity, with an AUC of 0.76 (95% CI, 0.58-0.94; P =.015).
DPP-4/CD26 immunohistochemical evaluation showed that all patients with CD with ileal disease in clinical remission (n = 5) had high apical DPP-4/CD26 expression, compared with 29% of patients with CD and clinical activity (n = 7), although this finding was not statistically significant (P =.190).
The researchers noted several study limitations. All patients were recruited from tertiary-level hospitals, only those with UC underwent endoscopic assessment, and the endoscopic evaluations and immunohistochemical assays were performed in a small population.
Disclosures: One of the study authors reported affiliations with pharmaceutical companies. Please see the original reference for a full list of disclosures.
Pinto-Lopes P, Melo F, Afonso J, et al. Fecal dipeptidyl peptidase-4: an emergent biomarker in inflammatory bowel disease. Clin Transl Gastroenterol. 2021;12(3):e00320. doi: 10.14309/ctg.0000000000000320