Sub-nanoliter metabolomics via mass spectrometry to characterize volume-limited samples.

The human metabolome provides a window into the mechanisms and biomarkers of various diseases. However, because of limited availability, many sample types are still difficult to study by metabolomic analyses. Here, we present a mass spectrometry (MS)-based metabolomics strategy that only consumes sub-nanoliter sample volumes. The approach consists of combining a customized metabolomics workflow with a pulsed MS ion generation method, known as triboelectric nanogenerator inductive nanoelectrospray ionization (TENGi nanoESI) MS. Samples tested with this approach include exhaled breath condensate collected from cystic fibrosis patients as well as in vitro-cultured human mesenchymal stromal cells. Both test samples are only available in minimum amounts. Experiments show that picoliter-volume spray pulses suffice to generate high-quality spectral fingerprints, which increase the information density produced per unit sample volume. This TENGi nanoESI strategy has the potential to fill in the gap in metabolomics where liquid chromatography-MS-based analyses cannot be applied. Our method opens up avenues for future investigations into understanding metabolic changes caused by diseases or external stimuli.

Use cases, best practice and reporting standards for metabolomics in regulatory toxicology.

Metabolomics is a widely used technology in academic research, yet its application to regulatory science has been limited. The most commonly cited barrier to its translation is lack of performance and reporting standards. The MEtabolomics standaRds Initiative in Toxicology (MERIT) project brings together international experts from multiple sectors to address this need. Here, we identify the most relevant applications for metabolomics in regulatory toxicology and develop best practice guidelines, performance and reporting standards for acquiring and analysing untargeted metabolomics and targeted metabolite data. We recommend that these guidelines are evaluated and implemented for several regulatory use cases.

The serum metabolomic study of intervention effects of the traditional Chinese medicine Shexiang Baoxin Pill and a multi-component medicine polypill in the treatment of myocardial infarction in rats.

A metabolomic approach based on liquid chromatography coupled with quadrupole time-of-flight detector (LC-Q-TOF/MS) was developed to investigate the therapeutic mechanism of a traditional Chinese medicine (TCM) formula Shexiang Baoxin Pill (SBP) and a multi-component medicine polypill (consisting of simvastatin (Sim), atenolol (Ate), ramipril (Ram), hydrochlorthiazide (Hyd) and aspirin (Asp), named as SARHA). Twenty-seven biomarkers were identified in the serum of MI rats. Thirteen related pathways and 4 main pathological processes including oxidative injury, energy metabolism dysfunction, amino acid metabolism dysfunction and inflammation are involved in MI development. Our study revealed that SBP showed better therapeutic effectiveness than the polypill on MI through regulation of the energy metabolism dysfunction, oxidative injury and inflammation. The combination agent polypill had only certain therapeutic effects on inhibiting oxidative injury and inflammation induced by MI. The reverse effect of the polypill on biomarkers related to MI was much better than mono-therapy groups.