Bayesian independent component analysis recovers pathway signatures from blood metabolomics data

J Proteome Res. 2012 Aug 3;11(8):4120-31. doi: 10.1021/pr300231n. Epub 2012 Jul 17.

Abstract

Interpreting the complex interplay of metabolites in heterogeneous biosamples still poses a challenging task. In this study, we propose independent component analysis (ICA) as a multivariate analysis tool for the interpretation of large-scale metabolomics data. In particular, we employ a Bayesian ICA method based on a mean-field approach, which allows us to statistically infer the number of independent components to be reconstructed. The advantage of ICA over correlation-based methods like principal component analysis (PCA) is the utilization of higher order statistical dependencies, which not only yield additional information but also allow a more meaningful representation of the data with fewer components. We performed the described ICA approach on a large-scale metabolomics data set of human serum samples, comprising a total of 1764 study probands with 218 measured metabolites. Inspecting the source matrix of statistically independent metabolite profiles using a weighted enrichment algorithm, we observe strong enrichment of specific metabolic pathways in all components. This includes signatures from amino acid metabolism, energy-related processes, carbohydrate metabolism, and lipid metabolism. Our results imply that the human blood metabolome is composed of a distinct set of overlaying, statistically independent signals. ICA furthermore produces a mixing matrix, describing the strength of each independent component for each of the study probands. Correlating these values with plasma high-density lipoprotein (HDL) levels, we establish a novel association between HDL plasma levels and the branched-chain amino acid pathway. We conclude that the Bayesian ICA methodology has the power and flexibility to replace many of the nowadays common PCA and clustering-based analyses common in the research field.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Algorithms
  • Amino Acids, Branched-Chain / blood
  • Bayes Theorem*
  • Blood Chemical Analysis*
  • Cluster Analysis
  • Data Interpretation, Statistical*
  • Humans
  • Linear Models
  • Lipoproteins, HDL / blood
  • Metabolomics
  • Models, Biological
  • Models, Statistical
  • Multivariate Analysis
  • Principal Component Analysis

Substances

  • Amino Acids, Branched-Chain
  • Lipoproteins, HDL