Current Metabolomics (v.2, #4)

Surgery is associated with release of local and systemic mediators which influence vascular and tissue homeostasis. The post-surgical release of acute phase reactants, particularly IL-6 and CRP, is reduced in minimally invasive surgery, compared with conventional surgery. Additionally, there is emerging evidence that leukocytes and Reactive Oxygen Species (ROS) are affected differentially by minimally invasive surgery.
ROS and mediators of oxidative stress influence vascular endothelium, organ perfusion and angiogenesis, and may be critical determinants of survival and outcome. ROS also influence cell proliferation and cell death and have been implicated in neoplastic signalling. Advances in ROS detection and oxidative stress signalling have shown cellular changes affected by minimally invasive surgery. It has been observed that the invasiveness of surgery is proportional to changes in phagocyte and lymphocyte ROS. A potential role for ROS signalling in the immune system is suggested by evidence of closer ROS/leukocyte correlation in patients undergoing minimally invasive surgery. At lower ROS levels, phagocyte and lymphocyte ROS following minimally invasive surgery implicate a homeostatic response with closer leukocyte/ROS correlations, whereas higher ROS in open surgery and greater leukocyte depletion indicate more cytotoxic signalling.
Interactions between humoral and cellular elements suggest that an integrated systems approach, using individual patient responses, should be used to analyse the response to surgical trauma and oxidative stress. These studies are being used to investigate ROS as biomarkers of the effects of surgery on vascular and pulmonary reactivity. ROS signalling may provide insights into post surgical trauma and its underlying pathology.

The Application of Metabolomic Profiling to the Effects of Physical Activity by Evangelia Daskalaki, Chris Easton, David G. Watson (233-263).
Physical activity and exercise are potent lifestyle interventions for the reduction of several psycho- somatic risks, including cardiovascular disease, diabetes and mild-to-moderate depression. The current review describes the studies which have utilised a metabolomics/ metabolite profiling approach in combination with exercise in the period between 1999-2014 in predominantly healthy subjects (N:64) and in a smaller subset of patient cohorts (N:10) between 2011-2014. A broad range of intervention types were used in both healthy and patient cohorts with varying exercise regimes with or without supplement use. Effects on purine metabolism, which have been known for over 40 years, were by far the most well-cited and persistent finding. Other reported effects included observations of: glucocorticoid and androgen metabolism, glycolysis and Krebs cycle, gluconeogenesis, fatty acid metabolism, fatty acid oxidation and pantothenic acid, amino acid oxidation, tryptophan metabolism and effects on microbiome metabolites. The discussion section draws observations from the very disparate studies together and links them to the general aspects of human metabolism.

Ion Mobility Spectrometry a Versatile Analytical Tool for Metabolomics Applications in Food Science by Lourdes Arce, Janneth Gallegos, Rocio Garrido-Delgado, Luis M. Medina, Stepanie Sielemann, Thomas Wortelmann (264-271).
Linear Ion Mobility Spectrometry (IMS) is a vanguard analytical technique for the determination of volatile and semi-volatile compounds, thanks to the gas-phase separation of the different ions under a weak electric field at atmospheric pressure. The ions migrate through a drift tube with defined length. Monitoring of the ion current reveals the ion drift time. The drift time correlates to the specific ion-mobility, a function of the ion mass, charge and collision cross section with the ambient gas.
In this article, IMS, a technology initially developed for detecting traces of explosive and narcotic residues, as well as chemical warfare agents will be presented to meet the special requirements of metabolomics analysis. With the right sampling approach, IMS enables the detection of a wide number of compounds from different chemistry families, including alcohols, aldehydes, aromatics, amines, esters and ketones, among others, even from most complicated and problematic matrices. The selectivity of IMS can be improved by coupling to Gas Chromatography or Mass Spectrometry in order to improve separation or detection of analytes respectively. Other types of IMS such as, Travelling Wave IMS (TWIMS) and High Field Asymmetric Waveform IMS (FAIMS) have also enhanced the analytical possibilities of this technique.

Similar samples from dry horse feed and dry cat food were differentiated by a simple protocol that relies on the acquisition of 1D 1H NMR spectra of aqueous extracts at increasing soaking times and a posterior multivariate analysis of the data. The sequential withdrawal of aliquots from the same samples increased the significance of the statistical models that detect differences among the samples. These differences were identified by the backscaled coefficients plots of supervised models, like orthogonal projection to latent structure discriminant analysis, and evaluated depending on the weight of the contribution to the class separation. Statistical total correlation spectroscopy was applied to the data and gave insight into the components of the aqueous extracts, especially in regards to the molecules responsible for the class separation.