Potential of the Plasma Nutriproteome to Predict Micronutrient Distributions in Undernourished Settings.

Objectives: Micronutrient deficiencies are common but remain ‘hidden' due to difficulty of assessment. We explored the plasma proteome to identify nutrient-correlated biomarkers that may predict multiple micronutrient status and deficiencies, possibly on a single platform in the future. Methods: We measured, in 500 6-8 year old Nepalese children, plasma concentrations of >20 vitamin/mineral indicators and acute phase proteins (APP) by conventional assays, and relative abundance of proteins by quantitative mass spectrometry, bioinformatics and linear mixed effects models (Herbrich S et al, 2012; Cole R et al, 2013). We identified ~980 proteins in >10% of subjects, and evaluated their strength of correlation with micronutrient and APP distributions. Comparisons were corrected for multiple comparisons, with a 10% threshold for false discoveries. Results: 142 proteins were correlated with plasma retinol, 6 with 25(OH) vitamin D, 119 with α- tocopherol, 12 with γ-tocopherol, 6 with PIVKA-II (reflecting vitamin K status), 89 for vitamin B6, 35 for ferritin and 7 for transferrin receptor (reflecting iron status), 232 for copper, 3 for selenium and none for folate, thyroglobulin (reflecting iodine status) or vitamin B12 (q>0.1 for all comparisons). Initial models with up to 6 covariates suggest an ability to explain 60-80% of the variation (R2) in retinol, α-tocopherol, vitamin B6 and copper, ~50% of the variation in ferritin and, the carotenoid, β-cryptoxanthin and 80-85% of variation in CRP and AGP. Other nutrient-protein models will be presented. Conclusions: Plasma nutrient-correlated proteomes exist that, with absolute quantification of candidate proteins, could provide a basis for multiple micronutrient status assessment of populations in the future.

Effect of Antenatal Micronutrient Supplementation on the Plasma Proteome in School Aged Children in Nepal.

Objectives: Antenatal micronutrient interventions may influence maternal and offspring health in chronically undernourished settings; however, molecular mechanisms remain largely unexplored. We examined effects of multiple combinations of antenatal micronutrients as supplements on the plasma proteome of offspring at 6-8 years of age. Methods: We applied quantitative mass spectrometry to measure plasma protein abundance in 500 children whose mothers had been randomized to receive daily supplements of folic acid (FA), iron-folic acid (IFA), iron-folic acid-zinc (IFAZn), multiple micronutrient (MM), or placebo (control) from 1st trimester to 3 months postpartum (all tablets contained vitamin A). We identified differentially abundant proteins and sets of proteins sharing a common biological function by enrichment analysis using the Gene Ontology (GO) database. Results: With a relaxed discovery threshold (false discovery rate <0.25), maternal FA supplementation increased the abundance of insulin-like growth factor-1 (IGF1) by 33.7 (95% CI: 14.7-55.8)%; maternal IFA supplementation increased tissue inhibitor of metalloproteinase 1 by 12.5 (5.9-19.6)%. All supplements containing iron-folic acid increased IGF1, IGF2, and IGFbinding protein 5 by 23.9 (9.1-40.7)%, 28.6 (10.7-49.4)%, and 23.7 (10.5-38.5)%, respectively, and decreased stromal interaction molecule 1 by 63.3 (36.7-78.8)%. With a discovery threshold of 0.05, maternal IFA supplementation negatively enriched proteins localized in microtubules (GO:5874) with an enrichment score (ES) of -0.62 and maternal IFA and MM supplementation positively enriched proteins with growth factor activity (GO:8083) with ES of 0.70 and 0.75, respectively (all p-values <0.0001). Conclusions: Antenatal micronutrient supplementation exerts subtle metabolic effects on proteins involved in regulating growth/development and intracellular structure in school-aged children.