ENDOCYTOSIS OF FLUORESCENT MICROSPHERES BY HUMAN ESOPHAGEAL EPITHELIAL-CELLS - COMPARISON BETWEEN NORMAL AND INFLAMED TISSUE

This paper examines the presence and characteristics of endocytosis by oesophageal epithelial cells. Biopsy specimens from normal and inflamed oesophagus were incubated in organ culture with fluorescent microspheres (0.1 and 0.01 mu m diameter). These markers were taken into early endosomes and the lysosomes of both the smaller differentiating prickle cells and the larger mature squamous cells. Confocal and electron microscopy showed that markers passed to the early endosomes and the lysosomes by endocytosis. The process was energy dependent. Larger. 1 mu m microspheres adhered to the epithelial cells but were not phagocytosed. Disaggregated cells were analysed by flow cytometry. Microspheres were endocytosed in proportion to the concentration in the culture medium in a dose dependent manner. Cells from inflamed oesophagus were significantly smaller (p=0.013) and took up significantly more microspheres than cells 6 om normal biopsy specimens (p=0.015). In conclusion, endocytosis oesophageal epithelial. increased in inflammation.