Application of Metabonomics in a Compound Ranking Study in Early Drug Development Revealing Drug-Induced Excretion of Choline into Urine

Abstract

Selecting drug candidates based on toxicity is an important step in early drug development. In this case study, it is shown how metabonomics is applied to a ranking study, in which drug candidates with equal pharmacological activities are selected based on least toxic side effects. The metabonomic analyses were carried out on an animal study that followed an established protocol for pilot toxicology/ranking studies in rats, however, not specifically modified for a metabonomic assessment. It is shown how conditions not specificially adopted for metabonomics investigations can significantly influence the metabolic profiles recorded by NMR. Furthermore, it is shown how the multivariate analysis of the NMR spectra identified an extreme excretion of an endogenous metabolite into urine induced by two out of the five drug candidates. The subsequent structure elucidation by two-dimensional NMR experiments and a subsequent validation by spiking experiments identified the metabolite as choline. The discussion of the mechanistic background for the excretion of choline, which is usually well-conserved in the body, results in two hypotheses of either a massive degradation of cell membranes or an inhibition of the choline oxidation. Although the validation of these hypotheses needs a follow-up study, the finding of a increased excretion of the important metabolite choline warrants exclusion of these two compounds as viable drug candidates from a metabonomics point of view.

Chemometrics in Metabonomics

“…ASCA was demonstrated on an intervention study examining the effect of vitamin C on the development of OA in guinea pigs. Dieterle et al 77 applied metabonomics to a compound ranking toxicity study where rat urine was collected and characterized using NMR spectroscopy. The design study included controls, multiple dose groups, and two time points.…”

Enzymatic flow injection method for rapid determination of choline in urine with electrochemiluminescence detection

“…For example, it is a precursor of membrane and lipoprotein phospholipids and the neurotransmitter acetylcholine; and thus is important for the integrity of cell membranes, lipid metabolism, and cholinergic nerve function [1,2]. The development a sensitive and rapid method for the determination of choline in biological fluids, such as plasma and urine, has become an important subject in the fields of biochemistry because it would certainly aid in studying the metabolism of this physiologically important substance [3,4]. Till now, there has been rare paper concerned with the development of a suitable method for the determination of free choline in the human urine.…”

Discovery of Metabolomics Biomarkers for Early Detection of Nephrotoxicity

“…Metabolomics has recently attracted increasing interest in the field of toxicology, since it has proven to be a fast and reproducible method directly reflecting biological events (Dieterle et al 2006). Metabolomics involves the determination of changes in the levels of endogenous or exogenous metabolites in biological samples, owing to physiological stimuli or genetic modification (Nicholson et al 1999).…”