The hydrophobic carotenoid, lutein, was conferred with aqueous solubility upon formulation into reconstituted discoidal high density lipoprotein particles, termed lutein nanodisks (ND). When formulated with phosphatidylcholine (PC), apolipoprotein (apo) A-I and lutein (formulation ratio = 5 mg PC/2 mg apoA-I/1 mg lutein), lutein solubilization efficiency in phosphate buffered saline (PBS) was ~90%. The UV/Vis absorbance maxima for lutein ND in PBS were red shifted by 6-13 nm versus the corresponding lutein absorbance maxima in ethanol. FPLC gel filtration chromatography gave rise to a single major absorbance peak in the size range of ND. Incubation of cultured ARPE-19 cells with lutein ND resulted in lutein uptake, as determined by HPLC analysis of cell extracts. Compared to control incubations, ARPE-19 cells incubated with lutein ND were protected from UV light-induced loss of cell viability. Consistent with this, reactive oxygen species generation, induced by exposure to UV irradiation, was lower in lutein-enriched cells than in control cells. Thus, uptake of ND-associated lutein protects ARPE-19 cells from UV light-induced damage. Taken together, the data indicate ND provide an aqueous lutein delivery vehicle for biotechnological or therapeutic applications.
Studies of "pre ß" high density lipoprotein (HDL) and reconstituted HDL (rHDL) have contributed to our understanding of the Reverse Cholesterol Transport pathway. The relative ease with which discoidal rHDL can be generated in vitro has led to novel applications including a) infusion of rHDL into patients to promote regression of atherosclerosis; b) use of rHDL as a miniature membrane for integration of transmembrane proteins in a native-like conformation and c) incorporation of hydrophobic bioactive molecules into rHDL, creating a delivery device. The present review is focused on bioactive agent containing rHDL. The broad array of hydrophobic bioactive molecules successfully incorporated into these particles is discussed, as well as the use of natural lipids and synthetic lipid analogs to confer distinctive binding activity. This technology remains in its infancy with the full potential of these simple, yet elegant, nanoparticles still to be discovered.
Drug Delivery Systems , Lipoproteins, HDL/metabolism , Animals , Biological Transport , Drug Carriers/chemistry , Drug Carriers/metabolism , Humans , Hydrophobic and Hydrophilic Interactions , Lipoproteins, HDL/chemistry
Depletion of coenzyme Q (CoQ) is associated with disease, ranging from myopathy to heart failure. To induce a CoQ deficit, C2C12 myotubes were incubated with high dose simvastatin. This resulted in a concentration-dependent inhibition of cell viability. Simvastatin-induced effects were prevented by co-incubation with mevalonic acid. When myotubes were incubated with 60 µM simvastatin, mitochondrial CoQ content decreased while co-incubation with CoQ nanodisks (ND) increased mitochondrial CoQ levels and improved cell viability. Incubation of myotubes with simvastatin also led to a reduction in oxygen consumption rate (OCR). When myotubes were co-incubated with simvastatin and CoQ ND, the decline in OCR was ameliorated. The data indicate that CoQ ND represent a water soluble vehicle capable of delivering CoQ to cultured myotubes. Thus, these biocompatible nanoparticles have the potential to bypass poor CoQ oral bioavailability as a treatment option for individuals with severe CoQ deficiency syndromes and/or aging-related CoQ depletion.
Ataxia/drug therapy , Mitochondrial Diseases/drug therapy , Muscle Weakness/drug therapy , Nanocomposites/chemistry , Simvastatin/adverse effects , Ubiquinone/deficiency , Ubiquinone/pharmacology , Animals , Ataxia/pathology , Cell Line , Cell Survival/drug effects , Heart Failure/chemically induced , Heart Failure/drug therapy , Heart Failure/pathology , Humans , Mice , Mitochondria/drug effects , Mitochondria/metabolism , Mitochondrial Diseases/pathology , Muscle Fibers, Skeletal/drug effects , Muscle Fibers, Skeletal/metabolism , Muscle Weakness/pathology , Muscular Diseases/chemically induced , Muscular Diseases/drug therapy , Muscular Diseases/pathology , Oxygen Consumption/drug effects , Simvastatin/pharmacology , Ubiquinone/chemistry , Ubiquinone/genetics
Coenzyme Q10 (CoQ10 ) is a strongly hydrophobic lipid that functions in the electron transport chain and as an antioxidant. CoQ10 was conferred with aqueous solubility by incorporation into nanoparticles containing phosphatidylcholine (PtdCho) and apolipoprotein (apo) A-I. These particles, termed CoQ10 nanodisks (ND), contain 1.0 mg CoQ10 /5 mg PtdCho/2 mg apoA-I (97% CoQ10 solubilization efficiency). UV/Vis absorbance spectroscopy of CoQ10 ND revealed a characteristic absorbance peak centered at 275 nm. Incorporation of CoQ10 into ND resulted in quenching of apoA-I tryptophan fluorescence emission. Gel filtration chromatography of CoQ10 ND gave rise to a single major absorbance peak and HPLC of material extracted from this peak confirmed the presence of CoQ10 . Incubation of cultured cells with CoQ10 ND, but not empty ND, resulted in a significant increase in the CoQ10 content of mitochondria as well as enhanced oxidative phosphorylation, as observed by a ~24% increase in maximal oxygen consumption rate. Collectively, a facile method to solubilize significant quantities of CoQ10 in lipid nanoparticles has been developed. The availability of CoQ10 ND provides a novel means to investigate biochemical aspects of CoQ10 uptake by cells and/or administer it to subjects deficient in this key lipid as a result of inborn errors of metabolism, statin therapy, or otherwise.
Biocompatible Materials/pharmacology , Mitochondria/metabolism , Ubiquinone/analogs & derivatives , Animals , Apolipoprotein A-I/chemistry , Biocompatible Materials/chemical synthesis , Biocompatible Materials/chemistry , Cell Line , Chromatography, Gel , Chromatography, High Pressure Liquid , Hep G2 Cells , Humans , Mice , Nanoparticles , Oxidative Phosphorylation/drug effects , Oxygen Consumption , Phosphatidylcholines/chemistry , Ubiquinone/chemical synthesis , Ubiquinone/chemistry , Ubiquinone/pharmacology
