A 67-year-old man with established coronary artery disease presents with BP 138/82, HR 78, on high-dose atorvastatin. PCSK9 inhibitor is initiated due to persistently elevated cardiovascular risk. Recent labs show LDL cholesterol decreasing from 55 mg/dL to 20 mg/dL and apolipoprotein B at 45 mg/dL. Carotid ultrasound shows stable atherosclerotic plaque without progression. No muscle pain or hepatic dysfunction reported. Which mechanism best explains the LDL reduction achieved by PCSK9 inhibitors?
- A)Increased activation of hepatic lipase in extrahepatic tissues
- B)Direct inhibition of hepatic cholesterol synthesis via HMG-CoA reductase
- C)Enhanced conversion of VLDL to LDL particles
- D)Inhibition of lipoprotein lipase-mediated triglyceride hydrolysis
- E)Prevention of PCSK9-mediated degradation of LDL receptors, increasing hepatic LDL uptakeGABARITO
Explicação
PCSK9 is a serine protease that targets LDL receptors for lysosomal degradation. PCSK9 inhibitors (monoclonal antibodies) bind and neutralize PCSK9, preventing receptor degradation. This increases hepatic LDL receptor density and enhances LDL particle clearanc... Ver explicação completa e trilha adaptativa →