RATIONALE Fatty acid esters of hydroxy fatty acids (FAHFAs) are recently discovered endogenous lipids with outstanding health benefits. FAHFAs are known to exhibit antioxidant, antidiabetic and anti-inflammatory properties. The number of known long chain FAHFAs in mammalian tissues and dietary resources increased recently because of the latest developments in high-resolution tandem mass spectrometry techniques. However, there are no reports on the identification of short chain fatty acid esterified hydroxy fatty acids (SFAHFAs). METHODS Intestinal contents, tissues, and plasma of rats fed with high-fat diet (HFD) and normal diet (ND) were analysed for fatty acids, hydroxy fatty acids, and FAHFAs using ultra-high-performance liquid chromatography (UHPLC) and linear trap quadrupole-Orbitrap mass spectrometry (LTQ Orbitrap MS) with negative heated electrospray ionization. RESULTS Untargeted analysis of total lipid extracts from murine samples (male 13-week old WKAH/HKmSlc rats) led to the identification of several new SFAHFAs of acetic acid or propanoic acid esterified long chain (>C20)-hydroxy fatty acids. Furthermore, MS3 analysis revealed the position of the hydroxyl group in the long chain fatty acid as C-2. The relative amounts of SFAHFAs were quantified in intestinal contents and their tissues (caecum, small intestine, and large intestine), liver, and plasma of rats fed with HFD and ND. The large intestine showed the highest abundance of SFAHFAs with a concentration range from 0.84 to 57 pmoles/mg followed by the cecum with a range of 0.66 to 28.6 pmoles/mg. The SFAHFAs were significantly altered between the HFD and ND groups, with a strong decreasing tendency under HFD conditions. CONCLUSIONS Identification of these novel SFHFAs can contribute to better understanding the chemical and biological properties of individual SFHFAs and their possible sources in the gut, which in turn helps us tackle the role of these lipids in various metabolic diseases.

中文翻译：

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使用超高效液相色谱/线性离子阱四极杆-Orbitrap质谱仪通过非目标分析在鼠模型中鉴定羟基脂肪酸（SFAHFAs）的短链脂肪酸酯。

原理羟基脂肪酸脂肪酸酯（FAHFA）是最近发现的内源性脂质，具有出色的健康益处。已知FAHFA具有抗氧化，抗糖尿病和抗发炎的特性。由于高分辨率串联质谱技术的最新发展，哺乳动物组织和饮食资源中已知的长链FAHFA的数量最近有所增加。然而，没有关于鉴定短链脂肪酸酯化的羟基脂肪酸（SFAHFA）的报道。方法分析高脂饮食（HFD）和普通饮食（ND）喂养的大鼠的肠内容物，组织和血浆中的脂肪酸，羟基脂肪酸，FAHFA和FAHFA使用超高效液相色谱（UHPLC）和线性阱四极杆Orbitrap质谱（LTQ Orbitrap MS）进行负加热电喷雾电离。结果从鼠类样本（雄性13周大的WKAH / HKmSlc大鼠）中进行总脂质提取物的非目标分析导致鉴定了乙酸或丙酸酯化的长链（> C20）-羟基脂肪酸的几种新的SFAHFAs。此外，MS3分析揭示了长链脂肪酸中的羟基的位置为C-2。在喂食了HFD和ND的大鼠的肠道内容及其组织（盲肠，小肠和大肠），肝脏和血浆中，对SFAHFA的相对量进行了定量。大肠的SFAHFA丰度最高，浓度范围为0。84至57 pmoles / mg，其次是盲肠，范围为0.66至28.6 pmoles / mg。HFA和ND组之间的SFAHFA发生了显着变化，在HFD条件下有很强的下降趋势。结论鉴定这些新型SFHFA可有助于更好地理解各个SFHFA的化学和生物学特性及其在肠道中的可能来源，从而有助于我们解决这些脂质在各种代谢性疾病中的作用。