Treatment of intestinal and liver features in cystic fibrosis mice by the osmotic laxative polyethylene glycol

Background: Cystic Fibrosis (CF) is a genetic disease affecting multiple organs, primarily the lungs and digestive system. Improved pulmonary management significantly improved life expectancy of CF patients. As a result, extrapulmonary manifestations, including gastrointestinal and liver-related symptoms, have become more relevant. We previously reported that the osmotic laxative polyethylene glycol (PEG), which hydrates the CF gut, decreased fecal bile acid loss in a CF knockout mouse model. In the current study we investigated the effect of PEG on intestinal fat and cholesterol absorption and on CF-related liver features in a CF mouse model with the most common CF-causing mutation.

Methods: Cftr^{ΔF508/ΔF508} (n=13) and wild-type (WT) (n=12) mice were treated with PEG for 2 weeks. The intestinal and hepatic effects of PEG were assessed by analysis of intestinal bile acid, cholesterol, and fat fluxes, transcriptome analysis as well as histology.

Results: PEG improved intestinal malabsorption of bile acids, fat, and cholesterol in Cftr^{ΔF508/ΔF508} mice. Transcriptome analysis showed that PEG partially restored the intestinal signaling of nuclear receptors RXR, FXR, and CAR/PXR, which are involved in bile acid and xenobiotic metabolism. PEG also reduced liver inflammation in CF mice as assessed by transcriptome and histological analyses.

Conclusions: PEG, a non-absorbable osmotic laxative, improved intestinal nutrient absorption, intestinal bile acid and xenobiotic signaling, as well as CF-related liver features. These findings highlight the potential for osmotic laxation to improve gastrointestinal complications of CF in humans.