Small-dense low-density lipoproteins are the predominant apoB-100-containing lipoproteins in cord blood

Objectives

Low density lipoprotein (LDL)-cholesterol level in cord blood is approximately 30%. The aim of our study was to specifically explore LDL apoB distribution across sizes in cord blood serum.

Design and methods

We studied 83 healthy neonates and 17 paired healthy mothers. Plasma glucose and serum lipids, such as low-density lipoprotein (LDL) cholesterol (LDL-C), HDL cholesterol (HDL-C) and triglycerides (TG), were measured using enzymatic methods. Distribution of apoB-100 was performed by western blot and immunodetection on native 4–12% polyacrylamide gels. LDL subclasses were analyzed by Lipoprint-LDL.

Results

Neonates show the expected lower content of apoB LDL and small dense LDL is the predominant apoB containing particle: 67 ± 7%. However, only 1.5% is sdLDL by Lipoprint. Maternal serum contains a large proportion of apoB in smaller LDL, 47 ± 6% as compared to non-pregnant women, 6 ± 1%, p < 0.001.

Conclusions

Neonates show the expected lower content of apoB–LDL but in an inverse distribution; sdLDL being the predominant particle. This novel finding for apoB sdLDL is consistent with previous data on HPLC studies showing increased middle and small-sized LDL lipid content in neonates as compared to adults which amounts to 84% of total LDL. Comparison of the results with Lipoprint LDL (lipids) with gradient gel electrophoresis native western blot (apoB-100) suggests that neonates carry fractions of small LDL that are comparatively poor in lipids as compared with their mothers. Further studies are warranted on the issue of sdLDL in neonates.