What is Apolipoprotein C-II?

Apolipoprotein C-II (ApoC-II) is a small apolipoprotein present on:

• Chylomicrons

• VLDL

• HDL

It plays a critical role in triglyceride metabolism.

Main Function

ApoC-II is an essential activator of Lipoprotein Lipase (LPL).

LPL function:

• Hydrolyzes triglycerides in chylomicrons and VLDL

• Releases free fatty acids for tissue uptake

Without ApoC-II → LPL cannot function effectively.

Clinical Significance

1️⃣ Familial Chylomicronemia Syndrome

ApoC-II deficiency leads to:

• Severe hypertriglyceridemia

• Elevated chylomicrons

• Recurrent pancreatitis

• Eruptive xanthomas

• Lipemic (milky) plasma

This condition resembles LPL deficiency.

2️⃣ Hypertriglyceridemia

Low or dysfunctional ApoC-II:

• Impaired triglyceride clearance

• Elevated plasma triglycerides

Seen in:

• Genetic disorders

• Severe metabolic disturbances

3️⃣ Pancreatitis Risk

Triglyceride levels >1000 mg/dL due to ApoC-II deficiency can cause:

• Acute pancreatitis

• Abdominal pain

• Nausea and vomiting

4️⃣ Metabolic Syndrome & Diabetes

Altered ApoC-II levels may contribute to:

• Insulin resistance

• Abnormal triglyceride metabolism

• Atherogenic dyslipidemia

5️⃣ Cardiovascular Disease

Imbalance between ApoC-II and ApoC-III affects:

• Triglyceride-rich lipoprotein metabolism

• Residual cardiovascular risk

ApoC-II itself is less commonly used as a routine CVD marker.