Smoking is known to cause several diseases. However, the underlying pathophysiological mechanisms are still not completely understood. In order to prevent these diseases it is of paramount importance to identify biomarkers helping to decipher the root cause of smoking induced perturbations in biochemical pathways.

Gas chromatography coupled to time-of-flight mass spectrometry (GC-TOF-MS) has evolved as a powerful tool for untargeted metabolomic profiling. It combines the separation power of GC with structural information obtained by high resolution mass spectrometry. GC-TOF-MS has been successfully applied in a previous study at ABF in order to identify differences in the metabolome between smokers and non-smokers under strictly controlled dietary conditions.

The purpose of the current study was to analyse the changes in the metabolome in different body fluids (blood, saliva, urine) of former smokers who decided to quit smoking. A human study with 60 healthy smokers was conducted in order to investigate the impact of smoking cessation at different time points on the metabolomic profile. The subjects stayed at the clinical research organisation for 24 h (8 a.m. to 8 a.m.) at time point (TP) 0, when they still smoke. Dietary intake as well as the biological sample collection procedure (plasma, urine, saliva) was performed under strictly-controlled conditions. TP 0 was used in the following as baseline/reference TP. The same conditions and procedures were repeated after smoking cessation for 1 week (TP 1), 1 month (TP 2) and 3 months (TP 3). In order to check the compliance with smoking abstinence, urine and saliva samples were collected and analysed for cotinine at increasing intervals.

The fully validated GC-TOF-MS method revealed differences in the plasma metabolome of smokers still smoking and after having quit. This presentation will share the first results on how the plasma metabolome changed over a period of three months of smoking abstinence.