In addition to pulmonary disease, people with cystic fibrosis (pwCF) can experience gastrointestinal (GI) complications, including impaired nutrient uptake, obstruction, and elevated risk of GI cancers. Despite the use of highly effective modulator therapies, CF-associated GI manifestations persist, and the mechanisms driving them are comparatively underexplored. Progress has been limited by the absence of models that reliably reproduce the human intestinal mucosal environment: animal models fail to capture human small intestinal physiology, and current in vitro approaches are unable to generate the full diversity of cell types. To address this gap, we developed an innovative human intestinal organoid model derived from induced pluripotent stem cells (iPSCs) to investigate the mechanisms underlying the pathophysiology of the CF intestine. We used this platform to test the hypothesis that altered mucus composition and aberrant intestinal cell biology impairs nutrient absorption in pwCF. We generated human intestinal organoids (HIOs) from iPSCs carrying common CFTR mutations (F508del, G542X, and W1282X) and compared them to wild-type controls. Upon xenograft, transplanted organoids (tHIOs) from all CFTR variants grew and matured to exhibit the distinct crypt-villus architecture of the small intestine. We used immunofluorescence staining to identify differentiated cell types, including enteroendocrine, Paneth, goblet, and BEST4 cells in tHIOs from all CFTR variants. Histological and immunofluorescence analysis revealed that CF tHIOS exhibited increased mucus retention and a shift toward acidic mucins, with a pronounced retention of MUC2 in goblet cells. Additionally, wheat germ agglutinin staining demonstrated notable glycoprotein accumulation clogging the crypts and lining the epithelium of CF tHIOs. We collected secreted mucus from the enclosed luminal space of mature tHIOs which revealed an elevated percent solid composition in CF tHIOs compared to controls. We are currently using Ussing chambers, enteroid cultures, and in vivo exposure to nutrients to define how this abnormal mucus may alter the absorptive capacity of CF small intestinal epithelium. This model provides a robust platform for modeling CF-associated GI pathophysiology, offering new opportunities to study manifestations of the disease. This human system is advantageous because it allows direct examination of aberrant CF small intestinal mucus without interference from the microbiome and other luminal factors. Additionally, tHIOs provide an opportunity to define how CFTR dysfunction disrupts intestine development, stem cell dynamics, and nutrient absorption, ultimately guiding the design of therapeutic strategies to mitigate GI complications in pwCF. This work was supported by the Cystic Fibrosis Foundation (MCCAUL23G0-GI) and a Pilot and Feasibility award from the UNC CFRTCC. This abstract was presented at the American Physiology Summit 2026 and is only available in HTML format. There is no downloadable file or PDF version. The Physiology editorial board was not involved in the peer review process.
Dodson et al. (Fri,) studied this question.