HPSE and type 1 diabetes mellitus: PI-88, which inhibits heparanase, an HS-degrading enzyme, may influence angiogenesis in spontaneous islet tumors in RIP-Tag2 mice [51], and HS proteoglycan (HSPG) in the basement membrane components of the islets may function as a physical barrier to protect pancreatic β-cells from attack by the inflammatory response in nonobese diabetic mice, which are a model of type 1 diabetes mellitus (T1DM) [52].