Vieujean, S.(1);Delanaye, P.(2);Seidel, L.(3);Cavalier, E.(4);Pierre, N.(5);Louis, E.(1);
(1)University of Liège- CHU Sart Tilman, Department of Gastroenterology, Liège, Belgium;(2)University of Liège- CHU Sart Tilman, Department of Dialysis-Nephrology-Transplantation, Liège, Belgium;(3)University of Liège, Biostatistics and medico-economic information department, Liège, Belgium;(4)University of Liège- CHU Sart Tilman, Department of Clinical Chemistry, Liège, Belgium;(5)GIGA Institute- University of Liège, Laboratory of Translational Gastroenterology, Liège, Belgium;
Matrix Gla protein (MGP) is an extracellular matrix protein. The inactive dephosphorylated and uncarboxylated form of this protein, called dp-ucMGP, has been shown to be increased in plasma of Crohn’s disease (CD) patients compared to non IBD patients (Brnic et al., 2020). Our aim was to assess if the plasmatic level of dp-ucMGP could reflect disease endoscopic activity and could be a potential marker of mucosal healing in CD.
The plasmatic level of dp-ucMGP was measured in a blood sample collected the same day as the ileocolonoscopy by CLIA method using IDS-iSYS InaKtif MGP. In addition to classical clinical data (gender, age, body mass index or BMI, disease duration, IBD treatment), endoscopic (disease localisation, Crohn’s Disease endoscopic index or CDEIS, as well as the presence of erythema, ulcer, oedema, pseudopolyp, stricture) and biological (C‑reactive protein or CRP) parameters were collected as well as faecal calprotectin to assess CD activity.
A total of 82 colonoscopies and dp-ucMGP assays were performed in 75 CD patients (44 females and 31 males; 43 colonic diseases, 22 ileal diseases and 19 ileocolic diseases) between October 2012 and November 2019. Out of the 82 performed colonoscopies, 22 showed a mucosal healing. Although MGP level was significantly correlated with CDEIS (r=0.21, p=0.040), it was neither associated with endoscopic remission (737 ± 205 pmol/L for patients in endoscopic remission vs 809 ± 332 pmol/L for those who were not, p=0.37), nor correlated with faecal calprotectin (r=0.074, p=0.51) or with CRP (r=0.12, p=0.27) levels. Plasma MGP levels increased significantly with age (r=0.38, p=0.0004) and disease duration (r=0.37, p=0.0006) but not with the BMI (r=0.045, p=0.69). Patients on corticosteroids at the time of colonoscopy had a higher level of MGP (1065 ± 531 pmol/L vs 729 ± 179 pmol/L, p=0.0003). There was no association with other treatments (5-ASA, immunomodulators, anti‑TNF, anti-α4β7 integrin or anti-IL-12/IL-23 p40 monoclonal antibody). Regarding endoscopic CD lesions, MGP values were significantly higher in cases of oedema (1153 ± 628 pmol/L vs 766 ± 261 pmol/L, p=0.019) and pseudopolyps (1099 ± 569 pmol/L vs 766 ± 264 pmol/L, p=0.018) but there was no association with the presence of other lesions.
The significant increase of plasmatic MGP levels with age, disease duration but also in patients with pseudopolyps suggests that this extracellular matrix protein could rather be a marker of tissue remodelling (not necessarily stricturing) and physiological ageing of the gut in CD than a marker of disease activity. The relevance of the plasmatic dosage of this protein to assess CD bowel damages deserves to be further investigated.