TIMP1 deficiency aggravates the TNBS-colitis course in mice and promotes post-surgical recurrence in Crohn's disease

Introduction: The extracellular matrix (ECM) activity plays a key role in intestinal wound healing.  Crohn’s disease (CD) could disturb the intestinal balance between metalloproteinases (MMPs) and tissue inhibitor of MMPs (TIMP).

Objective: 1) Study whether imbalances in ECM are related with early post-surgical recurrence (PSR) in the CD, and 2) its effect on TNBS-colitis.  

Methods:. ECM activity were measured by transcriptome analysis (RT-PCR validated) and protein microarrays from 20 CD ileo-cecal resections (5 of them with PSR<18 months post-surgery) and 10 controls. Paraffin embedded samples were stained with Masson’sTrichrome. Apart from that, TNBS-colitis course was assessed in wild-type and TIMP1-deficent mice by “in vivo” bioluminiscence imaging and tomography.

Results

The transcriptome reflected a high activity of ECM in CD, while protein analysis showed increased levels of all TIMPs in ileo-cecal resections compared to control. In addition, TIMP1 levels significantly correlated with MMP1 [R²=0.59] and MMP13 [R²=0.58]. In contrast to non-early PSR, early PSR patients showed reduced levels of TIMP1 [4.2 (3.1-6.4) vs. 3.1 (2.0-8.1); mg/ml], TGFβ1 [7.7 (4.7-8.5) vs. 4.5 (1.7-5.5); 10³ RU], and fibrosis [8 (5-10) vs. 4 (2-6)] Furthermore, TIMP1-deficient mice with TNBS-colitis showed higher bioluminiscence emission than wild-type mice (e.g. 6 days post-colitis: 6,93x10⁴ vs. 0,4x10⁴; fot·sr^-1·cm^-2; p<0.05), and a greater transmural thickness (2.8 vs. 0.9 mm²) and stenosis [4 (2-5) vs. 0 (0-2)].

Conclusions

CD patients with early PSR show lower basal levels of intestinal TIMP1 and TGFβ1 than patients without early PSR. TIMP1 deficiency leads to more aggressive TNBS-colitis course.