Quantitative determination of 12-hydroxyeicosatetraenoic acids by chiral liquid chromatography tandem mass spectrometry in a murine atopic dermatitis model

Establishment and Characterization of Mild Atopic Dermatitis in the DNCB-Induced Mouse Model

In dermatological research, 2,4-dinitrochlorbenzene (DNCB)-induced atopic dermatitis (AD) is a standard model as it displays many disease-associated characteristics of human AD. However, the reproducibility of the model is challenging due to the lack of information regarding the methodology and the description of the phenotype and endotype of the mimicked disease. In this study, a DNCB-induced mouse model was established with a detailed procedure description and classification of the AD human-like skin type. The disease was induced with 1% DNCB in the sensitization phase and repeated applications of 0.3% and 0.5% DNCB in the challenging phase which led to a mild phenotype of AD eczema. Pathophysiological changes of the dorsal skin were measured: thickening of the epidermis and dermis, altered skin barrier proteins, increased TH1 and TH2 cytokine expression, a shift in polyunsaturated fatty acids, increased pro-resolving and inflammatory mediator formation, and dysregulated inflammation-associated gene expression. A link to type I allergy reactions was evaluated by increased mast cell infiltration into the skin accompanied by elevated IgE and histamine levels in plasma. As expected for mild AD, no systemic inflammation was observed. In conclusion, this experimental setup demonstrates many features of a mild human-like extrinsic AD in murine skin.

The enantioselective separation and quantitation of the hydroxy-metabolites of arachidonic acid by liquid chromatography - tandem mass spectrometry

Arachidonic acid (AA) is a polyunsaturated fatty acid with a structure of 20:4(ω-6). Cytochrome P450s (CYPs) metabolize AA to several regioisomers and enantiomers of hydroxyeicosatetraenoic acids (HETEs). The hydroxy-metabolites (HETEs) exist as enantiomers in the biological system. The chiral assays developed for HETEs are so far limited to a few assays reported for midchain HETEs. The developed method is capable of quantitative analysis for midchain, subterminal HETE enantiomers, and terminal HETEs in microsomes. The peak area or height ratios were linear over concentrations ranging (0.01 -0.6 µg/ml) with r2 > 0.99. The intra-run percent error and coefficient of variation (CV) were ≤ ± 12 %. The inter-run percent error and coefficient of variation (CV)were ≤ ± 13 %, and ≤ 15 %, respectively. The matrix effect for the assay was also within the acceptable limit (≤ ± 15 %). The recovery of HETE metabolites ranged from 70 % to 115 %. The method showed a reliable and robust performance for chiral analysis of cytochrome P450-mediated HETE metabolites.

Heat-treated adzuki bean protein hydrolysates reduce obesity in mice fed a high-fat diet via remodeling gut microbiota and improving metabolic function

SCOPE

Heat-treated adzuki bean protein hydrolysates (APH) reduced cholesterol in vitro. However, it is unclear if APH have anti-obesity effects in vivo and, if so, the relationship between the effects and the improvement of gut microbiota composition and metabolic function.

METHODS AND RESULTS

Four groups of mice were fed either a normal control diet (NCD) or a high-fat diet (HFD) with or without APH for 12 weeks. In HFD-fed mice, APH supplementation significantly alleviated fat accumulation, dyslipidemia, insulin resistance, hepatic steatosis, and inflammation. In addition, APH supplementation regulated gut microbiota composition, reduced the abundance of harmful bacteria (Clostridium_sensu_stricto_1, Romboutsia, Blautia, Mucispirillum, Bilophila, and Peptococcus), enriched Lactobacillus and SCFA-producing bacteria (Lactobacillaceae, Eisenbergiella, Alistipes, Parabacteroides, Tannerellaceae, Eubacterium_nodatum_group, Acetatifactor, Rikenellaceae, and Odoribacter), and increased fecal SCFAs concentration. Importantly, APH supplementation significantly regulated the levels of serum metabolites, especially Lactobacillus-derived metabolites and tryptophan derivatives, which helped to alleviate obesity and its complications.

CONCLUSION

APH improved gut microbiota composition and metabolic function in mice and may help to prevent and treat obesity and related complications. This article is protected by copyright. All rights reserved.

Emerging role of 12/15-Lipoxygenase (ALOX15) in human pathologies

12/15-lipoxygenase (12/15-LOX) is an enzyme, which oxidizes polyunsaturated fatty acids, particularly omega-6 and -3 fatty acids, to generate a number of bioactive lipid metabolites. A large number of studies have revealed the importance of 12/15-LOX role in oxidative and inflammatory responses. The in vitro studies have demonstrated the ability of 12/15-LOX metabolites in the expression of various genes and production of cytokine related to inflammation and resolution of inflammation. The studies with the use of knockout and transgenic animals for 12/15-LOX have further shown its involvement in the pathogenesis of a variety of human diseases, including cardiovascular, renal, neurological and metabolic disorders. This review summarizes our current knowledge on the role of 12/15-LOX in inflammation and various human diseases.