COL1A1 and systemic sclerosis: We observed that Col1a1/MMP1 and Col1a2/MMP1 ratios were increased when HD fibroblast were stimulated with MPs from SSc patients with a longer disease duration compared to those with a shorter disease duration (median of 1.60 vs. 0.60, respectively, p<0.05, Figure 4A and 4.80 vs. 0.82, p<0.01, respectively, Figure 4B).