Abstract Body: Objective: Post-thrombotic syndrome (PTS) is a debilitating complication of deep vein thrombosis (DVT), and anticoagulation therapies for DVT often fail to prevent PTS. Experimental PTS may in part be mediated by matrix metalloproteinase (MMP)activity. Galectin-3 (Gal-3), encoded by the LGALS3 gene, plays a pivotal role in cell migration, activation, and inflammation. Previous studies in models of liver fibrosis and atherosclerosis have suggested that Gal-3 inhibition can modulate fibrotic and inflammatory responses. We hypothesized that Gal-3 inhibition could reduce vein wall fibrosis in a rodent model of venous thrombosis (VT).
Methods: Using a mouse model of complete inferior vena cava (IVC) stasis, C57BL/6 WT mice were treated with an oral Gal-3 inhibitor (GB1107, 10 mg/kg) for 8 days following induction of venous thrombosis. Masson’s trichrome staining of thrombosed IVC sections were evaluated to quantify vein wall collagen deposition. In vitro, inflammatory markers of fibrosis were assessed by qRT-PCR. THP-1 immortalized human macrophages (Mo/Mphage) were stimulated with vehicle control versus Gal-3 inhibitor. An endothelial-leukocyte adhesion functional assay was used to evaluate the effects of Gal-3 inhibition. Statistical analysis was performed using GraphPad Prism software.
Results: In vivo, Masson’s trichrome staining revealed that Gal-3 inhibition reduced vein wall collagen deposition compared to untreated controls 8 days post-VT (*p<0.05, Figure 1) In vitro, Gal-3 inhibition significantly decreased Matrix Metalloproteinase-9 (mmp-9) expression in THP-1 Mo/Mphage cells compared to untreated controls (**p<0.01, Figure 1). Finally, in a functional endothelial-leukocyte adhesion assay, Gal-3 inhibition significantly decreased cell adhesion compared to stimulated with TNF-α (****p<0.0001, Figure 1).
Conclusions: Galectin-3 inhibition significantly reduced vein wall fibrosis in vivo. Potential antifibrotic mechanisms of gal-3 indicated by our in vitro data include disruption of immune cell- endothelial cell interactions and suppression of monocyte derived mmp9 gene expression.
Keywords: Galectin-3, venous thrombosis, post-thrombotic syndrome, fibrosis, inflammation, mouse model.