Association of maternal weight with FADS and ELOVL genetic variants and fatty acid levels- The PREOBE follow-up.

Single nucleotide polymorphisms (SNPs) in the genes encoding the fatty acid desaturase (FADS) and elongase (ELOVL) enzymes affect long-chain polyunsaturated fatty acid (LC-PUFA) production. We aimed to determine if these SNPs are associated with body mass index (BMI) or affect fatty acids (FAs) in pregnant women. Participants (n = 180) from the PREOBE cohort were grouped according to pre-pregnancy BMI: normal-weight (BMI = 18.5-24.9, n = 88) and overweight/obese (BMI≥25, n = 92). Plasma samples were analyzed at 24 weeks of gestation to measure FA levels in the phospholipid fraction. Selected SNPs were genotyped (7 in FADS1, 5 in FADS2, 3 in ELOVL2 and 2 in ELOVL5). Minor allele carriers of rs174545, rs174546, rs174548 and rs174553 (FADS1), and rs1535 and rs174583 (FADS2) were nominally associated with an increased risk of having a BMI≥25. Only for the normal-weight group, minor allele carriers of rs174537, rs174545, rs174546, and rs174553 (FADS1) were negatively associated with AA:DGLA index. Normal-weight women who were minor allele carriers of FADS SNPs had lower levels of AA, AA:DGLA and AA:LA indexes, and higher levels of DGLA, compared to major homozygotes. Among minor allele carriers of FADS2 and ELOVL2 SNPs, overweight/obese women showed higher DHA:EPA index than the normal-weight group; however, they did not present higher DHA concentrations than the normal-weight women. In conclusion, minor allele carriers of FADS SNPs have an increased risk of obesity. Maternal weight changes the effect of genotype on FA levels. Only in the normal-weight group, minor allele carriers of FADS SNPs displayed reduced enzymatic activity and FA levels. This suggests that women with a BMI≥25 are less affected by FADS genetic variants in this regard. In the presence of FADS2 and ELOVL2 SNPs, overweight/obese women showed higher n-3 LC-PUFA production indexes than women with normal weight, but this was not enough to obtain a higher n-3 LC-PUFA concentration.

Determination of acylglycerols from biological samples with chromatography-based methods.

Lipids are the most diverse class of metabolites in mammalian physiology and dysregulation of lipid metabolism is linked to various diseases. Alterations in acylglycerols, a major class of lipids in plasma and adipose tissue, are involved in the pathogenesis of obesity and type 2 diabetes. Therefore, determination of acylglycerols is important to depict and unravel cellular mechanisms related to pathological outcomes, and specific molecular species of acylglycerols might be promising biomarker candidates. The variety of acylglycerols can be characterized in different ways. Enzymatic assays enable the determination of total tri- or diacylglycerols showing a possible relation to diseases, but they do not allow clarification of molecular mechanism. While gas chromatography can provide an overview of the fatty acid composition of total or separated lipids, a very detailed description of the individual molecular acylglycerol species is possible via liquid chromatography, particularly when combined with mass spectrometry. This review describes the determination of acylglycerols considering recent developments, with a focus on mammalian serum/plasma and tissue.