Dysregulation of MMP production and activity leads to extracellular matrix degradation and medial layer degeneration.[16] Examination of smooth muscle cells from abdominal aortic aneurysm shows an upregulated expression of MMP-9 and MMP-2.[17] Fluoroquinolones have been shown to affect the synthesis of collagen in the tendon cell and disorganization of the extracellular matrix in the cornea. This evidence concerns the gene MMP9 and abdominal aortic aneurysm.