Related Experiment Videos
Lipoprotein lipase with a defect in lipid interface recognition in a case with type I hyperlipidaemia
J Kobayashi1, K Shirai, Y Saito
1Second Department of Internal Medicine, School of Medicine, Chiba University, Japan.
European Journal of Clinical Investigation
|October 1, 1989
Summary
A patient with severe hypertriglyceridaemia had defective lipoprotein lipase (LpL). This LpL enzyme could not process fats in VLDL or chylomicrons, indicating a lipid recognition defect.
Area of Science:
- Biochemistry
- Molecular Biology
- Genetics
Background:
- Severe hypertriglyceridaemia is a condition characterized by extremely high triglyceride levels.
- Lipoprotein lipase (LpL) is a key enzyme responsible for hydrolyzing triglycerides in lipoproteins.
- Recurrent pancreatitis can be a severe complication of hypertriglyceridaemia.
Observation:
- A 14-year-old patient presented with severe hypertriglyceridaemia (up to 3600 mg/dL) and recurrent pancreatitis.
- Postheparin plasma (PHP) from the patient contained a defective LpL enzyme.
- The patient's LpL showed reduced activity against emulsified triolein and native chylomicrons.
Findings:
- Purified patient LpL hydrolyzed tributyrin but failed to hydrolyze triolein emulsified with phosphatidylcholine (PC) or in chylomicrons.
- Unlike normal LpL, the patient's LpL did not associate with very-low-density lipoprotein (VLDL).
- Patient LpL retained normal activity for triolein emulsified with lysophospholipid in the presence of apolipoprotein CII.
Implications:
- The findings suggest a specific defect in the lipid interface recognition of LpL, rather than a general catalytic defect.
- This LpL defect impairs the processing of triglyceride-rich lipoproteins like VLDL and chylomicrons.
- Understanding this specific LpL dysfunction could lead to targeted therapies for certain forms of hypertriglyceridaemia.