Elevated plasma levels of lipoprotein(a) are an independent risk factor for atherosclerotic disease. Which property of apolipoprotein(a) explains this association?
- A It activates lipoprotein lipase on endothelial surfaces
- B It binds scavenger receptors on macrophages directly
- C It shares sequence homology with plasminogen and can compete with plasminogen binding, impairing thrombolysis ✓
- D It inhibits hepatic LDL receptor expression
Correct answer: C. It shares sequence homology with plasminogen and can compete with plasminogen binding, impairing thrombolysis
Explanation
Apo(a) is structurally homologous to plasminogen, and Lp(a) therefore competes for plasminogen binding on fibrin clots and endothelium, reducing thrombolysis and favoring thrombotic events on top of its atherogenic lipid cargo. It is not itself taken up via scavenger receptors until modified. This dual proatherogenic and prothrombotic action makes elevated Lp(a) an independent cardiovascular risk factor.
Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.