Microplastic accumulation in fibrotic intestinal tissue and mesenteric adipose tissue in Crohn's disease patients.

Crohn's disease (CD) patients exhibit heightened vulnerability to environmental triggers. However, the impact of microplastics (MPs) on CD remains unexplored. This study investigates MPs in ileal segments and mesenteric adipose tissue from CD patients. We recruited paired involved and adjacent uninvolved ileal segments, along with attached creeping fat (CF) and adjacent uninvolved mesenteric adipose tissue (CD-MAT) samples to assess MPs exposure of CD patients. Using laser infrared imaging spectrometer, we identified 12 types of MPs, including Chlorinated polyethylene (CPE), Acrylate copolymer (ACR), Fluororubber, and Polyethylene (PE). MP concentrations were correlated positively with the severity of intestinal fibrosis. Laser Direct Infrared spectroscopy revealed that 31.96% of MPs were 20-50 μm in size. Our findings underscored that the high-risk practices, such as frequent invasive gastrointestinal tract examinations, exacerbated of MPs accumulation in fibrotic intestines. We detected a parallel change in the concentrations of MPs at the lesion sites, with a significant increase observed compared to the surrounding tissues. When compared to CD-MAT and uninvolved ileum, the concentration ratios of PU and AUR were higher in the more fibrotic regions of CF and involved ileum, whereas CPE and Fluororubber exhibited a concurrent decrease. This suggests that MPs can penetrate the epithelial barrier and enter both fibrotic intestines and CF. This study provided the first evidence of widespread MP contamination in the fibrotic intestine and adjacent mesenteric adipose tissue of CD patients, correlating with fibrosis severity and might function as an exacerbating factor in the development of CF and fibrotic intestines.