In this work, time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used for detecting systematic variations in the spatial and compositional distributions of lipids in human tissue samples. Freeze-dried sections of subcutaneous adipose tissue from six chronic kidney disease (CKD) patients and six control subjects were analysed by TOF-SIMS using 25 keV Bi-3(+) primary ions. Principal component analysis of signal intensities from different fatty acids, diacylglycerol and triacylglycerol ions showed evidence for systematic variations in the lipid distributions between different samples. The main observed difference in the spectra was a concerted variation in the signal intensities from the saturated lipids relative to the unsaturated lipids, while variations in the fatty acid chain lengths were considerably weaker. Furthermore, the three samples showing the lowest degree of saturation came from CKD patients, while three of the four samples with the highest degree of saturation were from control subjects, indicating that low saturation levels in the glycerol lipid distribution may be more frequent in patients with CKD. Systematic differences in the spatial distributions between saturated and unsaturated glycerol lipids were observed in several analysed areas. (c) 2008 Elsevier B.V. All rights reserved.