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    39 Very low-density lipoproteins (VLDL)
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    39 Very low-density lipoproteins (VLDL)

    VLDL: triglyceride-rich lipoproteins from the liver, how VLDL cholesterol is estimated, remnant cholesterol and risk.

    Very low-density lipoproteins (VLDL) are large lipoproteins made by the liver. They carry triglycerides, and some cholesterol, from the liver to muscles and fat tissue. As their triglycerides are removed by the enzyme lipoprotein lipase, VLDL particles shrink into intermediate-density lipoproteins (IDL) and finally LDL. VLDL and their remnants contain apolipoprotein B and contribute to atherosclerosis. The VLDL level rises and falls mainly with triglycerides.

    Lipid profileTriglyceride-rich lipoproteinsRemnant cholesterol
    VLDL-C (estimated)TG / 2.2 (mmol/L)
    Usual range≈ 0.1–0.8 mmol/L (5–30 mg/dL)
    Main cargotriglycerides from the liver
    BecomesIDL → LDL
    Lipoprotein classes from largest to smallest: chylomicrons, VLDL, IDL, LDL and HDL, with their size, main lipid cargo and role in atherosclerosis Blood lipoproteins (not to scale) Chylo-VLDLIDLLDLHDL 75–1200 nm30–80 nm25–35 nm18–25 nm5–12 nm dietary TGliver TGTG + cholesterolmostly cholesterolcholesterol, protein remnants atherogenicatherogenicatherogenicmain atherogenicreverse transport apoB-100 on VLDL, IDL, LDL apoA-I on HDL ← larger, lighter, more triglyceride smaller, denser, more protein →
    Figure 1. VLDL is a large, triglyceride-rich particle made by the liver. During circulation it loses triglyceride and becomes IDL and then LDL.

    How VLDL is estimated

    VLDL cholesterol is rarely measured directly. In most laboratories it is calculated from triglycerides: VLDL-C ≈ TG / 2.2 (mmol/L) or TG / 5 (mg/dL). This is the same assumption used in the Friedewald formula for LDL. It becomes inaccurate when triglycerides are above about 4.5 mmol/L. A related value, remnant cholesterol (total cholesterol − LDL-C − HDL-C), estimates the cholesterol in VLDL and IDL together.

    High VLDL

    High VLDL reflects increased hepatic production or slower clearance of triglyceride-rich particles. The causes are the same as for high triglycerides: excess calories, sugar and alcohol, abdominal obesity, insulin resistance and type 2 diabetes, fatty liver disease, hypothyroidism, kidney disease, some medicines and genetic dyslipidaemias. Raised remnant cholesterol has been associated with increased risk of ischaemic heart disease in large population studies, independently of LDL.

    Low VLDL

    Low values are usually harmless and accompany low triglycerides. Very low values occur in rare inherited conditions with impaired apoB production (hypobetalipoproteinaemia, abetalipoproteinaemia), malnutrition and severe liver disease.

    What to do

    Treat VLDL together with triglycerides: lose excess weight, cut sugar, refined carbohydrates and alcohol, be physically active and control blood glucose. Medication decisions depend on overall cardiovascular risk and LDL-C or non-HDL-C.

    References

    1. Mach F, Baigent C, Catapano AL, et al. 2019 ESC/EAS Guidelines for the management of dyslipidaemias: lipid modification to reduce cardiovascular risk. Eur Heart J. 2020;41(1):111–188. doi:10.1093/eurheartj/ehz455
    2. Friedewald WT, Levy RI, Fredrickson DS. Estimation of the concentration of low-density lipoprotein cholesterol in plasma, without use of the preparative ultracentrifuge. Clin Chem. 1972;18(6):499–502. doi:10.1093/clinchem/18.6.499
    3. Varbo A, Benn M, Tybjærg-Hansen A, et al. Remnant cholesterol as a causal risk factor for ischemic heart disease. J Am Coll Cardiol. 2013;61(4):427–436.

    This article is for general information and does not replace a consultation with a doctor. Laboratory results must be interpreted by a physician together with symptoms and other tests.

    Published on 13 May 2024