Lipoproteins
Lipoprotein(a) is an additional independent atherogenic particle.
Lipoproteins
- Lipoproteins are proteins bound to lipids, crucial for lipid transport throughout the body. They are classified based on their density and composition:
- Chylomicrons :Composed of 1% protein and 99% lipids, with 88% triacylglycerols.
- Transport lipids absorbed from the intestines to tissues like adipose and muscle.
- Very Low-Density Lipoprotein (VLDL) :Composed of 7-10% proteins and 90-95% lipids (56% triacylglycerol).
- Transport triacylglycerols from the liver to tissues needing them for energy or storage.
Read this in Specific Proteins in Clinical Diagnosis
What our notes say
- Lipoprotein(a) is an additional independent atherogenic particle. (Chemical Pathology Practice Examination)
- Other: chronic kidney disease and lipoprotein(a) elevation are increasingly recognised independent risk factors. (General & Systemic Pathology SAQ Paper II — 15 July 2025 (MBPA 3500, MKU Year 3,)
- The liver increases lipoprotein synthesis in response to low oncotic pressure, and lipoprotein lipase activity falls. (Paediatrics and Child Health end of semester examination (MBPE): 10 January 2023)
- Explain the classification of lipoproteins by density and their atherogenic potential. (5 marks) (Chemical Pathology Practice Examination)
- Features: heavy proteinuria (>3.5g/day), hypoalbuminaemia, generalized oedema, hyperlipidaemia (compensatory hepatic lipoprotein synthesis), increased infection/thrombosis risk (loss of immunoglobulins/antithrombin III in urine) (Ovarian & Colorectal Cancer: Risks, Pathogenesis, Staging)
- The liver compensates for protein loss by increasing lipoprotein synthesis. (Chemical Pathology MCQs: Diabetes, Renal & Liver Disease)
Study material on Lipoproteins
- Clinical Biochemistry - Comprehensive Study Notes
- Endocrine and Metabolic Pathology MCQs for Medical Students
- Specific Proteins in Clinical Diagnosis
- Chemical Pathology MCQs: Clinical Chemistry, Endocrine & Renal
- Chemical Pathology Practice Examination
- Chemical Pathology MCQs
- Comprehensive Guide to Nutrient Digestion and Absorption
- Blood Metabolites Measurement and Their Applications
- Blood Biochemistry
- LIPID AND LIPOPROTEIN DISORDERS MCQs
Practice questions on Lipoproteins
Which lipoprotein is responsible for transporting dietary triglycerides from the intestines to tissues?
- Chylomicrons
- VLDL
- LDL
- HDL
Answer: A. Chylomicrons are synthesized in the intestinal cells and are responsible for transporting absorbed dietary triglycerides and cholesterol from the intestines to peripheral tissues.
Which lipoprotein is primarily responsible for transporting cholesterol to tissues?
- HDL
- LDL
- VLDL
- Chylomicrons Correct
Answer: B. LDL carries cholesterol from liver to peripheral tissues and is the major atherogenic lipoprotein. ---
Which lipoprotein is MOST atherogenic and is the primary LDL-lowering target?
- HDL-cholesterol
- LDL-cholesterol (and non-HDL-C)
- VLDL
- Chylomicrons
Answer: B. LDL-cholesterol carries cholesterol to peripheral tissues and arterial walls → atherogenesis. LDL-C is the primary target for cardiovascular risk reduction (statins). Non-HDL-C (total − HDL) is an alternative target, capturing VLDL remnants and IDL as well.
Which lipoprotein is responsible for transporting dietary triglycerides from the intestines to tissues?
- VLDL
- LDL
- Chylomicrons
- HDL
Answer: C. ** Chylomicrons are the largest lipoproteins and transport dietary triglycerides from the intestines to other tissues. They are primarily involved in the transport of dietary fats. ---
Which lipoprotein is a transitional form between VLDL and LDL?
- Chylomicrons
- HDL
- IDL (Intermediate-Density Lipoprotein)
- Lipoprotein (a)
Answer: C. ** IDL (Intermediate-Density Lipoprotein) is a transitional form between VLDL and LDL, involved in lipid metabolism as VLDL loses triglycerides. ---
Which lipoprotein primarily carries cholesterol from the liver to peripheral cells?
- HDL
- LDL
- Chylomicrons
- VLDL
Answer: B. ** LDL (Low-Density Lipoprotein) primarily carries cholesterol from the liver to cells throughout the body. High levels of LDL can lead to plaque buildup in arteries, earning it the name "bad cholesterol."