Lipid Biochemistry USMLE Step 1 Practice Question
A 55-year-old man with metabolic syndrome presents with BP 148/92 mmHg, HR 88/min, and fasting labs showing triglycerides 450 mg/dL, HDL 32 mg/dL, glucose 118 mg/dL, and elevated apoB levels. Abdominal ultrasound shows no hepatic steatosis. He denies alcohol use. VLDL particle analysis reveals small, dense particles with reduced triglyceride content per particle. Which mechanism best explains small, dense VLDL particle production in this metabolic context?
Answer choices
- AEnhanced clearance of apoB-100-containing particles by LDL receptors
- BImpaired esterification of cholesterol by LCAT in HDL particles
- CDecreased activity of lipoprotein lipase in adipose tissue
- DIncreased hepatic uptake of remnant particles via apoE receptors
- EIncreased hepatic re-esterification of free fatty acids and impaired apoB-100 secretionCorrect answer
- FReduced hepatic expression of microsomal triglyceride transfer protein (MTP) leading to decreased VLDL assembly
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