Duck Oil-loaded Nanoemulsion Inhibits Senescence of Angiotensin II-treated Vascular Smooth Muscle Cells by Upregulating SIRT1.

Cellular senescence is associated with age-related vascular disorders and has been implicated in vascular dysfunctions. Here, we show that duck oil-loaded nanoemulsion (DO-NE) attenuates premature senescence of vascular smooth muscle cells (VSMCs) triggered by angiotensin II (Ang II). Compared with control nanoemulsion (NE), DO-NE significantly inhibited the activity of senescence-associated ß-galactosidase, which is a biomarker of cellular senescence, in Ang II-treated VSMCs. SIRT1 protein expression was dose- and time-dependently induced in VSMCs exposed to DO-NE, but not in those exposed to NE, and SIRT1 promoter activity was also elevated. Consistently, DO-NE also dose-dependently rescued Ang II-induced repression of SIRT1 expression, indicating that SIRT1 is linked to the anti-senescence action of DO-NE in VSMCs treated with Ang II. Furthermore, the SIRT1 agonist resveratrol potentiated the effects of DO-NE on VSMCs exposed to Ang II, whereas the SIRT1 inhibitor sirtinol elicited the opposite effect. These findings indicate that DO-NE inhibits senescence by upregulating SIRT1 and thereby impedes vascular aging triggered by Ang II.

Comparative effects of nanoemulsions loaded with duck oil and lard oil on palmitate-induced lipotoxicity.

The effects of duck oil and lard oil on lipotoxicity induced by saturated long-chain fatty acids were evaluated in HepG2 cells. Lipotoxicity triggered by palmitate, a saturated fatty acid, was inhibited more by duck oil-loaded nanoemulsion (DO-NE) than by lard oil-loaded nanoemulsion (LO-NE) and control nanoemulsion (NE) in HepG2 cells. Accumulation of reactive oxygen species and lipid vacuoles in HepG2 cells induced by palmitate treatment was inhibited by DO-NE but not by LO-NE. Consistently, treatment of HepG2 cells with DO-NE, but not with NE or LO-NE, significantly reduced the expression levels of peroxisome proliferator-activated receptor-γ2 and sterol regulatory element-binding protein-1, which are key regulatory proteins in hepatic lipid accumulation. In addition, the cleavage of poly (ADP-ribose) polymerase and caspase-3 were reduced more by DO-NE than by LO-NE, indicating that DO-NE directly attenuates cellular damage induced by palmitate. Collectively, these results imply that the biological activity of duck oil against palmitate-induced cellular damage is more potent than that of lard oil. PRACTICAL APPLICATIONS: Accumulated lipids in nonadipose tissues, especially the liver, cause lipotoxicity, a pathologic feature of hepatic disorders, by inducing oxidative stress. A nanoemulsion loaded with duck oil, which is a functional food widely consumed by Korean people, inhibited lipotoxicity by suppressing lipid accumulation in HepG2 cells exposed to palmitate, which mimic nonalcoholic fatty liver disease. Thus, we propose that duck oil can be used as a functional food to improve lipid-induced hepatic disorders.

Oxidative Stability and Quality Characteristics of Duck, Chicken, Swine and Bovine Skin Fats Extracted by Pressurized Hot Water Extraction.

The aim of this study was to investigate the oxidative status and quality characteristics of four animal skin-derived fats extracted using an identical extraction method. Pressurized hot water extraction, a green extraction method, was used to extract animal skin fats (duck, chicken, swine, and bovine skin). Multiple experiments were performed during accelerated storage at 60°C for 90 days. Quality characteristics, such as extraction yield, iodine value (IV), fatty acid composition, and fat viscosity were determined. In addition, indicators for oxidative status, including acid value (AV), peroxide value (PV), p-anisidine value (p-AV), thiobarbituric acid reactive substances (TBARS), conjugated dienes (CD), and total oxidation (totox) values were evaluated. The fat extraction yield was highest in bovine fat, followed by duck, swine, and chicken fats. The IV was higher in duck and chicken fats. Duck fats contained the most unsaturated fats and the least saturated fats. Fat oxidation indicators, such as PV, TBARS, and totox values, were relatively higher in duck fats during storage compared to the other fats. Other indicators, including AV, p-AV, and CD, were similar in duck, chicken, and swine fats. Viscosity was similar in all the tested fats but markedly increased after 70 days of storage in duck fats. Our data indicate that duck skin fat was more vulnerable to oxidative changes in accelerated storage conditions and this may be due to its higher unsaturated fatty acid content. Supplementation with antioxidants might be a reasonable way to solve the oxidation issue in duck skin fats.