HPSE2 and acute kidney injury: Given the fact that HPSE2 mutations in humans can be associated with kidney disease causing renal failure, we also sought colocalization of heparanase 2 with the kidney epithelial marker Na, K-ATPase (29) at Stage 42, when a pronephros has developed on each side of the embryo, each with a duct terminating in the cloaca.