Increased risk for vitamin A toxicity in severe hypertriglyceridemia

Area of Science:

• Endocrinology
• Nutritional Science
• Lipid Metabolism

Background:

• Vitamin A (retinol) is essential for vision, immune function, and cell growth.
• Hypervitaminosis A can result from excessive vitamin A intake, leading to toxicity.
• Type V hyperlipoproteinemia is a rare genetic disorder characterized by extremely high triglyceride and cholesterol levels.

Observation:

• A patient with malabsorption and type V hyperlipoproteinemia developed hypervitaminosis A during vitamin A supplementation.
• Elevated plasma vitamin A levels were observed, with a significant portion transported in the chylomicron-very low-density lipoprotein (VLDL) fraction.
• Retinol and retinyl esters were significantly higher in patients with type V hyperlipoproteinemia compared to controls.

Findings:

• Patients with type V hyperlipoproteinemia exhibit elevated retinol and retinyl ester concentrations.
• Retinol is present in the chylomicron-VLDL fraction in most patients with type V hyperlipoproteinemia, unlike in healthy individuals.
• This abnormal transport mechanism may contribute to the increased risk of hypervitaminosis A in these patients.

Implications:

• Severe hypertriglyceridemia, particularly in type V hyperlipoproteinemia, poses an increased risk for vitamin A toxicity.
• Monitoring vitamin A levels may be crucial for patients with type V hyperlipoproteinemia, especially those on supplementation.
• Understanding lipid-protein interactions in vitamin A transport can inform clinical management and dietary recommendations.