MMP9 and obesity due to melanocortin 4 receptor deficiency: A cohort study in healthy individuals showed an upregulation of COL1A1, COL3A1, and MMP2 mRNA levels in SM 28 days after overfeeding, with no changes in MMP9. Microarray-based tests revealed alterations in pathways related to ECM receptor interactions, focal adhesion and adherens junction, elucidating new evidence linking SM ECM remodeling and obesity-related insulin resistance [159].