P0263 Comparative analysis of the faecal biomarker potential of Plasminogen activator inhibitor type 1 (PAI-1) to the Calprotectin in Inflammatory Bowel Diseases
Authors: Jójárt B , Resál T , Bacsur P , Farkas B , Ivány E , Kajári L , Szabó V , Kata D , Földesi I , Pallagi P , Molnár T , Maléth J , Farkas K ,   Epithelial Cell Signaling and Secretion Research Group
Published: January 2025

Abstract

Background
Inflammatory Bowel Diseases (IBD) require lifelong treatment and patient monitoring. Current predictors of relapse and therapeutic success have limitations, mostly invasive, time-consuming, and expensive. The faecal biomarker can help in disease activity and therapeutic response monitoring by simple and non-invasive way. Faecal Calprotectin (FC) is the gold-standard, but it has many disadvantages. We previously described that the correlation between the faecal Plasminogen activator inhibitor type 1 (PAI-1) (FP) level and the endoscopic activity and therapeutic response promote that it could be used as a novel non-invasive faecal biomarker in IBD diagnosis.1 To observe the exact faecal biomarker potential, we aimed to define the FP level of IBD patients and subjects with other gastrointestinal (GI) diseases and compare it with the FC.

Methods
Faecal samples were collected from 84 patients with IBD (CD-active: 12, CD-inactive: 10, UC-active: 9, UC-inactive: 10) and other GI diseases [colorectal cancer (CRC): 10, diverticulosis [DIV]: 9, irritable bowel syndrome [IBS]: 5, Polyp: 10) and 9 healthy subjects. ELISA method was applied to define FP level and it was validated for stool samples by us. In our previous study, 0.68 ng/g PAI-1 level was defined as the cut-off value. For FC observation diagnostic FC ELISA kit (Orgentec) was used. FC cut-off value was 50 mg/g. ROC analysis was applied to define Youden-index, specificity, and sensitivity of the measured values.

Results
FP level was significantly higher in patients with active IBD compared to inactive IBD and healthy subjects. No significant differences were observed between CD-active and UC-active groups. In addition, FP concentrations were significantly increased in active IBD patients compared to inactive IBD, CRC, DIV, IBS, Polyp, and healthy subjects. However, FC showed the same pattern as FP, except at the inactive IBD and DIV. In these groups, there were no significant differences compared to the active IBD subjects. ROC analysis defined high specificity (88.9%) and moderate sensitivity (47.6%) values (TP: 10, FP: 7, FN: 11, TN: 56, PPV: 0.588, NPV: 0.836) at the FP measurements. Nevertheless, at FC levels 34.9% specificity and 95.2% sensitivity were measured (TP: 20, FP: 41, FN: 1, TN: 22, PPV: 0.328, NPV: 0.957). Calculated Youden-index was higher at the FP (0.37) compared to the FC (0.3).

Conclusion
Our results suggest that the FP level selectively increased in the active IBD and discriminated more specifically from the other GI diseases compared to the FC. However, the sensitivity was lower, but it could be improved by the increasing patient numbers. Thus, the FP level could be useful in the diagnosis of IBD independently or combined with FC.

References
1.Jójárt B, Resál T, Kata D, Molnár T, Bacsur P, Szabó V, Varga Á, Szántó KJ, Pallagi P, Földesi I, Molnár T, Maléth J, Farkas K. Plasminogen Activator Inhibitor 1 Is a Novel Faecal Biomarker for Monitoring Disease Activity and Therapeutic Response in Inflammatory Bowel Diseases. J Crohns Colitis. 2024 Mar 1;18(3):392-405. doi: 10.1093/ecco-jcc/jjad160. PMID: 37751311; PMCID: PMC10906952.