Host-parasite interactions during Entamoeba histolytica infection: an ex vivo human intestinal model

Amebiasis, caused by the protozoan parasite Entamoeba histolytica, remains a significant public health problem in specific endemic regions. Current experimental models have limitations in accurately replicating human pathogenesis, highlighting the need for alternative platforms that preserve tissue complexity and physiological context. This study aimed to evaluate E. histolytica infection using an ex vivo human precision-cut intestinal slice (PCIS) model by analyzing histological and molecular changes over time (1, 3, 12, 24, and 48 h post-infection). Tissue integrity and parasite invasion were assessed using immunohistochemistry, while the gene expression of parasite virulence factors and host cytokines was quantified by quantitative PCR (qPCR). The PCIS model remained viable and preserved tissue architecture during the first 24 h. Histological analysis revealed progressive epithelial damage and parasite invasion into the connective tissue. Parasite gene expression revealed distinct temporal expression patterns during infection. While the EhGal/GalNAc lectin maintained a relatively stable expression profile throughout the interaction, Ehambp and the cysteine proteases (Ehcp2 and Ehcp5) exhibited early activation patterns consistent with roles in parasite adhesion, tissue invasion, and extracellular matrix degradation. In contrast, genes associated with oxidative stress response and parasite survival (Ehnitro, Ehthioredox, and Ehdovasa) displayed increased expression at later stages of infection, suggesting adaptation to the intestinal microenvironment. Host immune response analysis revealed heterogeneous cytokine expression kinetics. Pro-inflammatory mediators, particularly tnf-α, tnf-β, il-2, il-4, and il-17, showed significant temporal variation during infection, whereas il-10 exhibited progressively increased expression over time. These findings support a dynamic and heterogeneous host immune response during early infection, characterized by distinct temporal expression patterns of pro-inflammatory and regulatory cytokines, rather than a simple Th1-Th2 transition. Overall, these findings demonstrate that the PCIS model is a valuable platform for characterizing the temporal dynamics of host-parasite interactions during early E. histolytica infection and provides a physiologically relevant system for investigating the molecular and cellular mechanisms underlying amebiasis.