Development of new approaches to elucidate the metabolism of nutritionally relevant bioactive compounds

Mass spectrometry imaging (MSI) has emerged in the last decades as a powerful methodology for understanding complex biological systems (Eberlin et al., Anal Chem 2011). In detail, MSI application results in a simultaneously spatial distribution map of a wide range of chemical compounds from a tissue section. MSI has been largely applied in drug research, to shed light on the spatio-temporal aspects of biology, and in clinically relevant areas, to provide better diagnoses and prognoses and to assess treatment in disease (Caprioli, J Biomol Tech 2019). Because of its versatility in the detection of several chemically different molecules, as recently proposed also for (poly)phenol metabolites in vivo (Nguyen et al., Sci Rep 2019), MSI will be applied in the framework of ONFOODS: a desorption electrospray ionization (DESI) probe will be purchased to elucidate the spatial in vivo (poly)phenol metabolism and absorption.

Available commercial standard of pure (poly)phenols will be fed to mice. Frozen intestinal (both small and large) and hepatic segments will be sliced at the cross-sectional face and tissues will be analysed using UHPLC-MS fitted with a DESI probe. Native, human and colonic metabolites will be analysed in sliced tissues to map the in situ absorption and metabolite production. 
MSI method will be further implemented using (poly)phenol-rich foods, to elucidate the matrix effect on non-nutrient absorption. Besides intestine and liver, other tissue cross-sectional frozen segments will be obtained, including brain, heart, kidney, adipose tissue, and analysed to check for the ability of different target tissues to pick up and absorb circulating bioactive metabolites.
Finally, new more sustainable application will be explored, namely reliable in vitro human tissue models, including 3D tissue models.

Thanks to decades of experience in non-nutrient metabolism, an innovative approach will be explored to elucidate more in depth the in vivo metabolism of health promoting non-nutrient compounds. 
With this study, we expect to:

• Develop an innovative analytical MSI method, applied to (poly)phenol metabolites, to elucidate the in situ metabolism and absorption of health promoting molecules. 
• Shed light on tissue uptake of possible bioactive metabolites to hypothesize their in situ bioactivity.
• Apply the innovative approach to reliable sustainable 3D tissue models, as a possible alternative approach to reduce animal use.