ACE and diabetes mellitus: Currently, commercially available synthetic protease inhibitors targeting host proteases include (1) thrombin and Factor Xa inhibitors for coagulation (such as dabigatran and rivaroxaban); (2) angiotensin converting enzyme (ACE) inhibitors for hypertension (such as lisinopril); (3) DPP-4 inhibitors for diabetes (such as sitagliptin); and (4) proteasome inhibitors for multiple myeloma (such as bortezomib) (Figure 2).