Distribution of immunochemically defined apoB-containing lipoprotein subclasses in T1D

Area of Science:

• Cardiovascular Science
• Endocrinology
• Lipid Metabolism

Background:

• Type 1 diabetes (T1D) in young women is associated with coronary heart disease (CHD) risk, independent of traditional lipid risk factors.
• Abnormalities in apolipoprotein B (apoB)-containing lipoprotein subclasses may contribute to this increased cardiovascular risk.

Purpose of the Study:

• To investigate whether specific apoB-containing lipoprotein subclasses are altered in young women with T1D.
• To determine if these lipoprotein abnormalities correlate with glycemic control (HbA1c) and could explain the elevated CHD risk.

Main Methods:

• Immunochemical isolation and quantification of five apoB-containing lipoprotein subclasses.
• Analysis of 37 young, otherwise healthy subjects with T1D (mean age 31.8 years) on conventional insulin therapy.
• Comparison of lipoprotein subclass profiles with healthy controls.

Main Results:

• Women with T1D exhibited significantly higher levels of cholesterol-rich Lp-B particles compared to controls.
• An over-representation of Lp-B particles within the total apoB particle pool was observed in T1D women.
• HbA1c levels strongly correlated with Lp-B particle concentration and apoB subclasses containing apoC-III.

Conclusions:

• A disturbance in Lp-B particle transport, characterized by increased absolute and relative numbers, is present in women with T1D.
• This disturbance may stem from portal hypoinsulinemia and reduced LDL B,E receptor activity.
• These altered lipoprotein dynamics represent a potential mechanism for enhanced CHD risk in T1D women, even with normal LDL and apoB levels.