Evaluation of Plasma AA/DHA+EPA Ratio in Obese Romanian Children

Abstract

The aim of the study was to evaluate the plasma profile of arachidonic acid (AA), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA), as well to analyze the relationship of Omega 6/Omega 3 ratio with anthropo-metric parameters and insulin resistance markers. Material and methods: Plasma levels of free fatty acids (FFAs) were measured using a high-throughput LC-MS AB Sciex4600 in 202 children (127 obese and 75 non-obese), age and sex-matched. Lipid and glucose profiles were assessed with current laboratory methods, while insulin resistance and beta-cell function were evaluated using HOMA-IR and HOMA-β respectively. Results: In obese children, AA and AA/(DHA+EPA) ratio were significantly higher regardless of age and gender. In the lowest quartile of DHA, there was a clear trend for insulin resistance, with plasma insulin level, HOMA-IR, and HOMA-β significantly higher compared to the highest quartile of DHA. After adjustment for age and gender DHA remains a negative predictive factor for insulin resistance. Waist-to-height ratio (WHtR), a marker of visceral obesity was higher in children with a higher AA/(DHA+EPA) ratio. Conclusions: In obese children, the AA is higher in concordance with insulin resistance. Additionally, children with a higher AA/(DHA+EPA) ratio have greater BMI, fat mass, waist circumference, and WHtR, important indicators of central adiposity, and cardio-metabolic disorders. LC/MS is a versatile tool for Omega ratio assessment, especially in children where the sample size is a limiting factor for metabolic and nutrition evaluation.

Development and Validation of an LC-MS/MS Method for the Determination of Plasma and Red Blood Cell Omega Fatty Acids: A Useful Diagnostic Tool

“…A shorter time for this reaction, of only 1-2 h, proved to be insufficient; however, the duration of 17 h allows for samples to be ready for analysis the next day after starting the sample preparation. The LC-MS/MS methodology, including sample preparation, proved to be simple to use and was successfully applied in a number of clinical studies, some already published [19,20]. The validation of the method, however, also highlighted some important aspects that need to be taken into consideration when using the method, such as assuring there is enough time and personnel/equipment availability to process RBC membrane samples immediately after collection and at least to the point of analyte liquid-liquid extraction with hexane, in order to assure the accuracy of the determinations.…”