An analysis of intestinal morphology and incretin-producing cells using tissue optical clearing and 3-D imaging

The emerging role of IL-22 as a potential radiosensitivity biomarker for radiation-induced intestinal injury

Considering the beneficial role played by IL-22 in alleviating radiation-induced intestinal injury through its promotion of epithelial regeneration, it was hypothesized that individuals with elevated IL-22 levels might display either minimal intestinal injury or increased resistance following ionizing irradiation exposure. To assess the impact of IL-22 on intestinal radiosensitivity, IL-22 expression levels was detected in serum of normal mice. Mice naturally with high or low levels of IL-22 or pretreated with IL-22 or anti-IL-22 were subjected to 10 Gy of total abdominal radiation (TAI). Daily observation, morphometric analysis, quantitative reverse transcriptase polymerase chain reaction, immunohistochemistry and western blot were employed to measure weight loss, survival rate, cell proliferation and death, and DNA damage. Furthermore, influence of IL-22 pretreatment on survival of intestinal organoid exposed to 6 Gy X-rays was evaluated. The results showed that IL-22 expression levels were varied between individuals. Surprisingly, mice with high IL-22 levels displayed exacerbated intestinal injury manifesting as increased weight loss, reduced regeneration capacity and more cell apoptosis. Notably, a strong positive correlation between weight loss and IL-22 expression level was observed. Additionally, pretreatment with IL-22 resulted in increased mortality accompanied by enhanced cell apoptosis and DNA damage in crypt of early exposure, as well as diminished survival of intestinal organoid, while pretreatment with anti-IL-22 antibody alleviated the intestinal injury. In this study, we established a direct link between IL-22 and radiosensitivity, suggesting IL-22 could be used as a potential biomarker for predicting individual intestinal radiosensitivity prior to radiation exposure.

Intestinal Morphology and Glucose Transporter Gene Expression under a Chronic Intake of High Sucrose

Sucrose is a disaccharide that is degraded into fructose and glucose in the small intestine. High-sucrose and high-fructose diets have been reported, using two-dimensional imaging, to alter the intestinal morphology and the expression of genes associated with sugar transport, such as sodium glucose co-transporter 1 (SGLT1), glucose transporter 2 (GLUT2), and glucose transporter 5 (GLUT5). However, it remains unclear how high-fructose and high-sucrose diets affect the expression of sugar transporters and the intestinal morphology in the whole intestine. We investigate the influence of a chronic high-sucrose diet on the expression of the genes associated with sugar transport as well as its effects on the intestinal morphology using 3D imaging. High sucrose was found to increase GLUT2 and GLUT5 mRNA levels without significant changes in the intestinal morphology using 3D imaging. On the other hand, the delay in sucrose absorption by an α-glucosidase inhibitor significantly improved the intestinal morphology and the expression levels of SGLT1, GLUT2, and GLUT5 mRNA in the distal small intestine to levels similar to those in the proximal small intestine, thereby improving glycemic control after both glucose and sucrose loading. These results reveal the effects of chronic high-sugar exposure on glucose absorption and changes in the intestinal morphology.