Background: Altered lipid metabolism and plasma fatty acid (FA) levels are associated with colorectal cancer. Obesity and elevated waist circumference (WC) increase the likelihood of developing precancerous colon adenomas. Methods: Venous blood was collected from 126 males, ages 48 to 65 years, who received routine colonoscopies. Plasma phospholipid (PPL) FAs were isolated, derivatized, and then analyzed using gas chromatography. ORs and 95% confidence intervals were determined using polytomous logistic regression after adjusting for confounding factors [i.e., age, smoking, WC, and body mass index (BMI)]. Results: PPL palmitic acid (PA) was inversely correlated with the presence of colon adenomas (P = 0.01). For each unit increase in palmitoleic acid (OR, 3.75; P = 0.04) or elaidic acid (OR, 2.92; P = 0.04), an individual was more likely to have adenomas relative to no colon polyps. Higher enzyme activity estimates (EAE) of stearoyl-CoA desaturase-1 (SCD-1; P = 0.02) and elongation of very long chain fatty acids protein-6 (ELOVL-6; P = 0.03) were associated with an individual being approximately 1.5 times more likely to have an adenoma compared with no polyps. Conclusions: PPL FAs and EAEs, which have previously been associated with colorectal cancer, are significantly different in those with adenomas when compared with those without polyps. PPL PA, elaidic acid, and SCD-1 and ELOVL-6 EAEs are associated with adenomas independent of BMI and WC. Impact: PPL PA, elaidic acid, and SCD-1 and ELOVL-6 EAEs are associated with adenomas even after adjusting for obesity-related risk factors and may function as novel biomarkers of early colorectal cancer risk. Cancer Epidemiol Biomarkers Prev; 25(3); 498–506. ©2015 AACR.

Obesity is associated with dysregulated lipid metabolism and adipokine secretion. Our group has previously reported obesity and adipokines are associated with % total fatty acid (FA) differences in plasma phospholipids. The objective of our current study was to identify in which complex lipid species (i.e., phosphatidylcholine, sphingolipids, etc) these FA differences occur. Plasma lipidomic profiling (n = 126, >95% Caucasian, 48–65 years) was performed using chromatographic separation and high resolution tandem mass spectrometry. The responses used in the statistical analyses were body mass index (BMI), waist circumference (WC), serum adipokines, cytokines, and a glycemic marker. High-dimensional statistical analyses were performed, all models were adjusted for age and smoking, and p-values were adjusted for false discovery. In Bayesian models, the lipidomic profiles (over 1,700 lipids) accounted for >60% of the inter-individual variation of BMI, WC, and leptin in our population. Across statistical analyses, we report 51 individual plasma lipids were significantly associated with obesity. Obesity was inversely associated lysophospholipids and ether linked phosphatidylcholines. In addition, we identify several unreported lipids associated with obesity that are not present in lipid databases. Taken together, these results provide new insights into the underlying biology associated with obesity and reveal new potential pathways for therapeutic targeting.

Supplementation with omega-3 (n-3) fatty acids may improve cognitive performance and protect against cognitive decline. However, changes in brain phospholipid fatty acid composition after supplementation with n-3 fatty acids are poorly described. The purpose of this study was to feed increasing n-3 fatty acids and characterise the changes in brain phospholipid fatty acid composition and correlate the changes with red blood cells (RBCs) and plasma in mice. Increasing dietary docosahexaenoic (DHA) and eicosapentaenoic acid (EPA) did not alter brain DHA. Brain EPA increased and total n-6 polyunsaturated fatty acids decreased across treatment groups, and correlated with fatty acid changes in the RBC (r > 0.7). Brain cis-monounsaturated fatty acids oleic and nervonic acid (p < .01) and saturated fatty acids arachidic, behenic, and lignoceric acid (p < .05) also increased. These brain fatty acid changes upon increasing n-3 intake should be further investigated to determine their effects on cognition and neurodegenerative disease.

Newborn screening (NBS) laboratories cannot accurately compare mass spectrometry-derived results and cutoff values due to differences in testing methodologies. The objective of this study was to assess harmonization of laboratory proficiency test (PT) results using quality control (QC) data. Newborn Screening Quality Assurance Program (NSQAP) QC and PT data reported from 302 laboratories in 2019 were used to compare results among laboratories. QC materials were provided as dried blood spot cards which included a base pool and the base pool enriched with specific concentrations of metabolites in a linear range. QC data reported by laboratories were regressed on QC data reported by the Centers for Disease Control and Prevention (CDC), and laboratory’s regression parameters were used to harmonize their PT result. In general, harmonization tended to reduce overall variation in PT data across laboratories. The metabolites glutarylcarnitine (C5DC), tyrosine, and phenylalanine were displayed to highlight inter- and intra-method variability in NBS results. Several limitations were identified using retrospective data for harmonization, and future studies will address these limitations to further assess feasibility of using NSQAP QC data to harmonize PT data. Harmonizing NBS data using common QC materials appears promising to aid result comparison between laboratories.