Development of an in vitro triculture model of intestine inflammation to assess the immunomodulatory properties of cassava and roselle, two African green leafy vegetables

Abstract

The intestine integrity and function are crucial for nutrient absorption and to prevent the entry of harmful antigens. In sub-Saharan Africa, frequent infections and enteric dysfunction can cause intestinal inflammation that is associated with stunting. Therefore, to study the anti-inflammatory effects of cassava and roselle leaves, commonly consumed as sauces, we developed an in vitro triculture model of intestine inflammation using intestinal Caco-2 (colorectal adenocarcinoma) and HT29-MTX (goblet cell-like) together with the macrophage-like THP-1 cells. Stimulation of this model with lipopolysaccharide/interferon-γ resulted in mucus over-production, higher pro-inflammatory cytokine release and loss of intestinal barrier integrity due to increased permeability. Polar/non-polar extracts and digested sauces from cassava and roselle leaves reduced cytokine production in both intestinal and THP-1 cells to different extents and restored barrier integrity and permeability. The developed and validated triculture model of inflamed intestine thus demonstrated the anti-inflammatory properties of cassava and roselle leaves, despite moderate responses.

Keywords

• Caco-2/HT29 biculture
• THP-1 macrophages
• Leaf extract
• In vitro digestion
• Intestinal permeability
• Cytokines