Date of Completion

9-14-2016

Embargo Period

9-12-2016

Keywords

lutein, nanoemulsion, bioavailability, hepatic steatosis, guinea pigs

Major Advisor

Maria Luz Fernandez, PhD

Associate Advisor

Hedley C Freake, PhD

Associate Advisor

Alison Kohan, PhD

Associate Advisor

Ji-Young Lee, PhD

Associate Advisor

Yangchao Luo, PhD/Jose Manautou, PhD

Field of Study

Nutritional Science

Degree

Doctor of Philosophy

Open Access

Open Access

Abstract

Lutein is a xanthophyll synthesized by plants. In biological systems, lutein has antioxidant and anti-inflammatory properties, which could protect against chronic diseases. Despite its potential as a bioactive food component, lutein intake is low among Americans. In addition, lutein has low bioavailability, making it difficult to achieve biological effects. One approach to overcome these challenges is the use of nanotechnology.

This project evaluated the effects of a lutein nanoemulsion (NANO) on hepatic steatosis and systemic inflammation in guinea pigs. Our hypothesis was that NANO lutein would be more bioavailable and, therefore, more effective than powdered lutein (PL) in protecting against cholesterol-induced damage.

The nanoemulsion had an average particle size of 165.4 nm, a PDI of 0.195 and a ζ-potential of -40.5 mV, indicating a stable and monodisperse preparation.

Twenty-four male Hartley guinea pigs were allocated to one of three groups (n=8/group): control (0 mg lutein), PL (0.02% lutein) or NANO (0.02%

nanoemulsified lutein). All diets contained 0.25% cholesterol. After 6 wk, plasma, livers, and adipose tissue were collected for analysis. During the study, animals in both treatment groups consumed an average of 3.5 mg lutein/day. The NANO group had higher plasma and liver lutein concentrations compared to PL, indicating that lutein given in a nanoemulsion is more bioavailable.

In the liver, the NANO group had lower steatosis scores, accumulation of total and esterified cholesterol, and plasma ALT when compared to PL and control. Hepatic oxidized LDL was lower in both PL and NANO compared to control. Further, mRNA expression of DGAT2 was lower in the NANO group when compared to control or PL.

In plasma, the NANO group had higher LDL and HDL cholesterol concentrations and VLDL, LDL and HDL particle number compared to PL and control. Furthermore, the NANO group had 15% higher free cholesterol concentrations in adipose tissue, resulting in higher concentrations of inflammatory markers compared to the other treatments.

Overall, this nanoemulsion increased the bioavailability of lutein and protected the liver while plasma lipoproteins and systemic inflammation were increased, suggesting that the metabolic effects of this particular nanoemulsion are not protective to all tissues in guinea pigs

Download

Share

COinS