MMP1 and autosomal dominant polycystic kidney disease: Interestingly, and in contrast to the fact that ADPKD kidneys develop fibrosis, there are reports of elevated MMP1 activity in ADPKD [31], with increased MMP1 activity correlating with common ADPKD cardiovascular events (such as intracranial aneurysms, which is one of the most serious complications of ADPKD and often results in sudden death).