Oxidizability of apolipoprotein B-containing lipoproteins, levels of lipid peroxidation products and antioxidants in normal pregnancy

Coenzyme Q10, carotenoid, tocopherol, and retinol levels in cord plasma from multiethnic subjects in Hawaii

Coenzyme Q10 (Q10), carotenoids, tocopherols, and retinol are the major circulating lipid-phase micronutrients (LPM) known to help mitigate oxidative damage and prevent chronic diseases. However, the functions of these compounds in newborns are little understood. This is due, in part, to the paucity of studies reporting their concentrations in this population. We measured Q10, carotenoids, tocopherols, and retinol in cord plasma from 100 multiethnic subjects living in Hawaii using HPLC with diode array and electrochemical detection. Appropriate internal standards were used including, for the first time, custom designed oxidized (UN10) and reduced (UL10) Q10 analogues. These compounds reflected the oxidation of UL10 to UN10 that occurred during sample processing and analysis and thus permitted accurate adjustments of natively circulating Q10 levels. All LPM measured were much lower in cord than in peripheral plasma. Cord plasma levels of total carotenoids, tocopherols, and retinol were approximately 10-fold, 3- to 5-fold and 1.5- to 3-fold lower than those in children or women. Cord plasma levels of total Q10 (TQ10; median, 113 ng/mL) were approximately 2-fold or 7- to 9-fold lower than peripheral plasma levels of neonates or children and adults, respectively. In contrast, the UN10/TQ10 ratio was substantially higher in cord (24%) than in peripheral plasma of children (3-4%) or adults (9%). Among the 5 ethnic groups in our cohort, no differences were observed in the levels of UN10, UL10, or TQ10. However, significant differences in many of the LPM were observed between ethnicities. More research is needed to explain these phenomena.

Risk factors for cardiovascular disease in women: relationship to lipid peroxidation and oxidative stress

Many risk factors that promote cardiovascular disease (CVD) have been identified. These include hypertension, hypercholesterolemia, diabetes, decreased estrogen in post-menopausal women, increased homocysteine, and cigarette smoking. It has recently become clear that a mechanism common to these risk factors is oxidative stress. CVD risk factors specific to women are parity, oophorectomy, pre-eclampsia, and menopause. There are several proposed mechanisms to explain these women-specific associations, such as reduced lifetime exposure to estrogen and insulin resistance, but the underlying mechanism is still unclear. One fact that did not receive much attention is the role of the oxidation hypothesis in these reproductive factors-CVD associations. In fact, pregnant, oophorectomized, and post-menopausal women exhibit higher levels of lipid peroxidation than non-pregnant, non-oophorectomized and pre-menopausal women, respectively. We propose that the increased levels of lipid peroxidation during these states are responsible, at least in part, for their increased risk of CVD. This review extends the concept of the oxidation hypothesis of CVD to reproductive risk factors in women. It also addresses the potential role of oxidative stress in the hyperthyroidism-CVD relationship, as hyperthyroidism is a common disorder that most frequently occurs in women. We also discuss how screening human populations for reactive oxygen species (ROS) levels could help identify groups with a high level of ROS that may be at risk of developing CVD.