Evaluation of the Antioxidant Activity of Lutein/Zeaxanthin Early Administered to Premature Newborns

Lutein is the most important carotenoid present selectively in certain tissues of the human body, mainly at the level of the retina, macula (hence the name) and lens. In tissues and serum, lutein is found together with a carotenoid dihydroxide, its isomer, zeaxanthin. Lutein and zeaxanthin are present at the level of the umbilical cord and pass through the placental barrier and are also present in the plasmatic ones, in breast milk and especially in the colostrum. Concerning the way of administrating, the lutein presents, through its specific characteristics, an elevated bioavailability after oral administration. The hematic levels of lutein, after providing nutriments rich in carotenoids, are increased with 67% from the 14% observed at beta-carotene. Through interdisciplinary and coordinated studies, performed both in vitro and in vivo, there were identified different action mechanisms; particularly, investigators have demonstrated a defense mechanism of the tissue function by lutein, which is produced through the neutralization (quench) phenomenon of the singlet oxygen and reactive oxygen species (ROS). This action provides molecules with different activities: an antioxidant function, anti-inflammatory properties, properties which promote anti-tumoral effects, induction of detoxification enzymes and positive effect on proteins promoting the communication between joints (up-regulation). Recently, there have appeared experimental and chemical data proving that the oxidative stress and harmful actions determined by ROS can play an important role in the pathogenesis of many neurological diseases as Alzheimer, Parkinson in adult and ROP and NEC in newborns.

This is due to the fact that the nervous system is characterized by membranes rich in polyunsaturated fats, the first cellular compounds affected by ROS attack through the lipid peroxidation. A similar mechanism can appear to certain ocular tissues (macula, lens, retina) which, containing high amounts of polyunsaturated fat acids, are more vulnerable than other structures with oxidative degradations induced by ROS.

Due to the fact that carotenoids are amongst the most powerful antioxidants existing in nature, there are being developed new researches concerning the functional role of these substances in preventing neurodegenerative diseases in newborns.

Because these polyunsaturated fat acids are very sensitive to oxidation, the modification of their plasmatic levels influences the state of the antioxidant systems on the mother and subsequently to the foetus. Many studies have proved that the increase of the susceptibility to the peroxidation of polyunsaturated fat acids on pregnant women is accompanied by an equivalent increase of the tocopherol plasmatic concentration which, immediately after birth, decrease sharply.

The plasmatic concentrations of the newborns' antioxidants were lower than those of the mothers. In the umbilical cord, the levels of tocopherols and carotenoids are significantly lower than the ones registered in the maternal plasma and the concentration of polyunsaturated fat acids on the newborn is significantly higher and a lot more increased than on the mother.