A metabonomic approach to the investigation of drug-induced phospholipidosis: an NMR spectroscopy and pattern recognition study

H-1 NMR spectroscopy of urine and pattern recognition analysis have been us ed to study the metabolic perturbations caused following dosing of five nov el drug candidates, two of which (GWA, GWB) caused mild lung and liver phos pholipidosis, whilst the rest GWC-GWE) did not cause any detectable toxicit y. Urine samples were collected predose, 0-8 h, 8-16 h, 16-24 h and 24-32 h after single, oral dosing with each compound to Han Wistar rats (n=3 per g roup), and liver and lung samples for were taken at 48 h for histology. H-1 NMR spectra of whole urine were acquired, processed and subsequently analy sed using principal component analysis. All animals administered the drug c andidates showed a significant reduction in serum triglycerides and those a nimals administered either GWA or GWB mere observed to have foamy alveolar macrophages and the presence of multilamellar bodies in hepatocytes by elec tron microscopy. In the plot of the first two principal components, urinary spectra of those animals dosed with GWA or GWB mapped separately to contro ls, all pre-dose samples and animals dosed with GWC-GWE. Inspection of the principal components loadings indicated an increase in urinary phenylacetyl glycine with a concomitant decrease in urinary citrate and 2-oxoglutarate. possibly constituting a never urinary biomarker set for phospholipidosis. T his work exemplifies the use of Nn IR spectroscopy and pattern recognition methods for the detection of novel biomarker combinations for poorly unders tood toxicity types and the potential in screening novel drugs for toxicity .