Inactive matrix Gla protein is elevated in patients with inflammatory bowel disease

Abstract

Background: Matrix Gla protein (MGP) is a vitamin K dependent peptide which has an established role in suppression of vascular calcification. Recent studies have pointed to a possible link between immunomodulatory effect of MGP and inflammatory bowel disease (IBD).

Aim: To compare plasma levels of dephosphorylated and uncarboxylated MGP (dp-ucMGP) between IBD patients and controls.

Methods: This cross-sectional study was conducted on 70 patients with IBD (30 patients with ulcerative colitis and 40 patients with Crohn's disease) and 60 age and gender matching healthy controls. Plasma dp-ucMGP levels were analyzed from blood samples by CLIA method using IDS-iSYS InaKtif MGP (Immunodiagnostic Systems, Frankfurt, Germany) according to the manufacturer's instructions. fecal calprotectin (FC) levels were determined from stool samples by turbidimetric immunoassay method using Bühlmann fecal calprotectin turbo assay (Bühlmann Laboratories Aktiengesellschaft, Schonenbuch, Switzerland). Other parameters were analyzed according to the standard laboratory procedures.

Results: Plasma levels of dp-ucMGP were significantly higher in patients with IBD compared to the healthy control group (629.83 ± 124.20 pmol/mL vs 546.7 ± 122.09 pmol/mL, P < 0.001), and there was no significant difference between patients with Crohn's disease and patients with ulcerative colitis (640.02 ± 131.88 pmol/mL vs 616.23 ± 113.92 pmol/mL, P = 0.432). Furthermore, a significant positive correlation of plasma dp-ucMGP levels was found with both FC levels (r = 0.396, P < 0.001) and high sensitivity C-reactive protein (hsCRP) levels (r = 0.477, P < 0.001). Moreover, in the total study population a significant positive correlation was found between dp-ucMGP with age (r = 0.210, P = 0.016) and waist circumference (r = 0.264, P = 0.002). Multiple linear regression analysis showed that dp-ucMGP levels retained significant association with FC (β ± SE, 0.06 ± 0.02, P = 0.003).

Conclusion: Study results support experimental data of MGP immunomodulatory IBD effect and indicate potential involvement in the pathophysiology of the disease, and possibly extraintestinal manifestations.

Keywords: Crohn's disease; Fecal calprotectin; Inflammatory bowel disease; Matrix Gla protein; Ulcerative colitis.