Petra Prochazkova

Anorexia nervosa (AN) is associated with profound alterations in gut microbiota and host metabolic profiles. While previous studies have primarily focused on the acute phase of AN, the chronic form, severe and enduring anorexia nervosa (SEAN), remains underexplored in terms of microbiome dynamics. In this study, we characterized gut microbiota composition (via 16S rRNA gene amplicon sequencing), serum and fecal metabolites (via mass spectrometry), and an extensive range of clinical, anthropometric, biochemical, and psychiatric parameters in females with acute AN, SEAN, and in healthy controls. SEAN patients exhibited higher antidepressant usage and greater lifetime stress exposure. Acute AN patients presented with more pronounced eating disorder severity and depressive symptoms. Elevated levels of intestinal fatty acid-binding protein in SEAN patients suggest mucosal damage. Microbiota analysis revealed reduced alpha diversity and distinct community composition in both AN groups, with SEAN showing the greatest interindividual variability. Both AN cohorts exhibited significantly lower serum and fecal γ-aminobutyric acid (GABA) levels, which were negatively correlated with taxa such as Christensenellaceae , Ruminococcaceae , and Escherichia-Shigella , i.e., microorganisms potentially associated with GABA degradation or impaired synthesis. Additionally, reductions in short-chain fatty acids suggest impaired microbial fermentation and dysregulation of the gut-brain axis. Collectively, these findings reveal progressive, functionally relevant changes in microbiota-host interactions in SEAN. These alterations likely reflect the persistent disease state and may contribute to its continuation.

Annelids and mollusks, both in the superphylum of Lophotrochozoa (Bilateria), are important ecological groups, widespread in soil, freshwater, estuarine, and marine ecosystems. Like all invertebrates, they lack adaptive immunity; however, they are endowed with an effective and complex innate immune system (humoral and cellular defenses) similar to vertebrates. The lack of acquired immunity and the capacity to form antibodies does not mean a lack of specificity: invertebrates have evolved genetic mechanisms capable of producing thousands of different proteins from a small number of genes, providing high variability and diversity of immune effector molecules just like their vertebrate counterparts. This diversity allows annelids and mollusks to recognize and eliminate a wide range of pathogens and respond to environmental stressors. Effector molecules can kill invading microbes, reduce their pathogenicity, or regulate the immune response at cellular and systemic levels. Annelids and mollusks are “typical” lophotrochozoan protostome since both groups include aquatic species with trochophore larvae, which unite both taxa in a common ancestry. Moreover, despite their extensive utilization in immunological research, no model systems are available as there are with other invertebrate groups, such as Caenorhabditis elegans or Drosophila melanogaster, and thus, their immune potential is largely unexplored. In this work, we focus on two classes of key soluble mediators of immunity, i.e., antimicrobial peptides (AMPs) and cytokines, in annelids and bivalves, which are the most studied mollusks. The mediators have been of interest from their first identification to recent advances in molecular studies that clarified their role in the immune response.

The originality of the present study is the description of CuO NP interaction with earthworm immune cells and subsequent physiological response from thein vitroperspective.