Multimodal Imaging Mass Spectrometry of Murine Gastrointestinal Tract with Retained Luminal Content Shows Molecular Localization Patterns

Digestive diseases impact 62 million people a year in the United States. Despite the central role of the gut to human health, past imaging mass spectrometry (IMS) investigations into the gastrointestinal tract are incomplete. The gastrointestinal tract, including luminal content, harbors a complex mixture of microorganisms, host dietary content, and immune factors. Existing imaging approaches remove luminal content, and images focus on small regions of tissue. Here, we demonstrate the use of a workflow to collect multimodal imaging data for both intestinal tissue and luminal content. This workflow for matrix-assisted laser desorption/ionization imaging mass spectrometry retains luminal content and expands the amount of tissue imaged on one slide. Results comparing tissue and luminal content show unique molecular distributions using multimodal imaging modalities including protein, lipid, and elemental imaging. Leveraging this method to investigate intestinal tissue infected with Clostridioides difficile compared to control tissue shows clear differences in lipid abundance of various lipid classes in luminal content during infection. These data highlight the potential for this approach to detect unique biological and markers of infection in the gut. ### Competing Interest Statement The authors have declared no competing interest.