Intestinal and Hepatic Uptake of Dietary Peroxidized Lipids and Their Decomposition Products, and Their Subsequent Effects on Apolipoprotein A1 and Paraoxonase1

Baoyuan decoction inhibits atherosclerosis progression through suppression peroxidized fatty acid and Src/MKK4/JNK pathway-mediated CD 36 expression

BACKGROUND

Baoyuan decoction (BYD) has been widely utilized as a traditional prescription for the treatment of various conditions such as coronary heart disease, aplastic anemia, and chronic renal failure. However, its potential efficacy in improving atherosclerosis has not yet been investigated.

PURPOSE

Our research aimed to assess the potential of BYD as an inhibitor of atherosclerosis and uncover the underlying mechanism by which it acts on foam cell formation.

STUDY DESIGN AND METHODS

High-fat diet-induced ApoE-/- mice were employed to explore the effect of BYD on atherosclerosis. The differential metabolites in feces were identified and analyzed by LC-Qtrap-MS. In addition, we utilized pharmacological inhibition of BYD on foam cell formation induced by oxLDL in THP-1 cells to elucidate the underlying mechanisms specifically in macrophages.

RESULTS

The atherosclerotic plaque burden in the aortic sinus of ApoE-/- mice was notably reduced with BYD treatment, despite no significant alterations in plasma lipids. Metabolomic analysis revealed that BYD suppressed the increased levels of peroxidized fatty acids, specifically 9/13-hydroxyoctadecadienoic acid (9/13-HODE), in the feces of mice. As a prominent peroxidized fatty acid found in oxLDL, we confirmed that 9/13-HODE induced the overexpression of CD36 in THP-1 macrophages by upregulating PPARγ. In subsequent experiments, the decreased levels of CD36 triggered by oxLDL were observed after BYD treatment. This decrease occurred through the regulation of the Src/MMK4/JNK pathway, resulting in the suppression of lipid deposition in THP-1 macrophages.

CONCLUSIONS

These results illustrate that BYD exhibits potential anti-atherosclerotic effects by inhibiting CD36 expression to prevent foam cell formation.

Lipid Structure Influences the Digestion and Oxidation Behavior of Docosahexaenoic and Eicosapentaenoic Acids in the Simulated Digestion System

Omega-3 fatty acids such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are essential for human health but prone to oxidation. While esterification location is known to influence the stability of omega-3 in triacylglycerols (TAGs) in oxidation trials, their oxidative behavior in the gastrointestinal tract is unknown. Synthesized ABA- and AAB-type TAGs containing DHA and EPA were submitted to static in vitro digestion for the first time. Tridocosahexaenoin and DHA as ethyl esters were similarly digested. Digesta were analyzed by gas chromatography, liquid chromatography-mass spectrometry, and nuclear magnetic resonance spectroscopy. Besides the formation of di- and monoacylglycerols, degradation of hydroperoxides was detected in ABA- and AAB-type TAGs, whereas oxygenated species increased in tridocosahexaenoin. Ethyl esters were mainly unaffected. EPA was expectedly less susceptible to oxidation prior to and during the digestion process, particularly in sn-2. These results are relevant for the production of tailored omega-3 structures to be used as supplements or ingredients.

Dietary triacylglycerol hydroperoxide is not absorbed, yet it induces the formation of other triacylglycerol hydroperoxides in the gastrointestinal tract

The in vivo presence of triacylglycerol hydroperoxide (TGOOH), a primary oxidation product of triacylglycerol (TG), has been speculated to be involved in various diseases. Thus, considerable attention has been paid to whether dietary TGOOH is absorbed from the intestine. In this study, we performed the lymph duct-cannulation study in rats and analyzed the level of TGOOH in lymph following administration of a TG emulsion containing TGOOH. As we successfully detected TGOOH from the lymph, we hypothesized that this might be originated from the intestinal absorption of dietary TGOOH [hypothesis I] and/or the in situ formation of TGOOH [hypothesis II]. To determine the validity of these hypotheses, we then performed another cannulation study using a TG emulsion containing a deuterium-labeled TGOOH (D2-TGOOH) that is traceable in vivo. After administration of this emulsion to rats, we clearly detected unlabeled TGOOH instead of D2-TGOOH from the lymph, indicating that TGOOH is not absorbed from the intestine but is more likely to be produced in situ. By discriminating the isomeric structures of TGOOH present in lymph, we predicted the mechanism by which the intake of dietary TGOOH triggers oxidative stress (e.g., via generation of singlet oxygen) and induces in situ formation of TGOOH. The results of this study hereby provide a foothold to better understand the physiological significance of TGOOH on human health.