Flow cytometry of oesophageal mucosal biopsies; epidermal growth factor receptor, and CD15

The study of the process of fluid-phase endocytosis in cervical squamous cells using fluorescent microspheres

Physiological processes in cervical squamous epithelium have not been extensively studied. Perhaps understandably, most of the research has concentrated on the pathology of the cervix, in particular dysplasia and malignancy. Fluid-phase endocytosis is a physiological process which has been demonstrated to be important in understanding disease development at other squamous epithelial sites, e.g. oesophagus. In this study, we have demonstrated by a new methodology developed in our laboratory using fluorescent microspheres and flow cytometry that fluid-phase endocytosis occurs in cervical squamous cells. The process has been shown to be dose- and time-dependent. This novel approach provides a means to improve our understanding of the physiological functions of the cervix and may provide insight into the pathogenesis of cervical neoplastic and non-neoplastic disease.

Eradication of Helicobacter pylori normalizes elevated mucosal levels of epidermal growth factor and its receptor

OBJECTIVE

Helicobacter pylori (H. pylori) infection has been linked to gastric cancer. The factors that promote carcinogenesis remain unknown. Epidermal growth factor (EGF) has been shown to be a potent epithelial mitogen and oncoprotein when sustained over expression occurs. Our aim was to compare gastric mucosal levels of EGF and its receptor (EGFR) among controls, H. pylori infected subjects, and subjects following H. pylori eradication using quantitative flow cytometric analysis.

METHODS

Patients referred for evaluation of dyspepsia underwent EGD and six antral biopsies were performed (two each for rapid urease testing (RUT), histopathology, and flow cytometry). Controls were those found to be H. pylori negative while subjects had confirmed infection. The study patients were treated, then had repeat EGD with biopsies.

RESULTS

There were 17 controls and 28 cases. Mean EGF and EGFR values were 2.69 and 2.46 for controls and 4.67 and 4.64 for subjects. Subjects' mean EGF was 73% higher (p = .035) and EGFR was 88% higher (p = 0.029) than controls. After treatment, the subjects' mean values declined 55% (p = 0.0001) for EGF and 40% (p = 0.002) for EGFR. Three subjects had persistent infection and showed no change in their EGF/EGFR levels. No difference was found among factor levels with respect to endoscopic findings.

CONCLUSIONS

Both EGF and EGFR from gastric antral biopsies are increased nearly 2-fold in infection with H. pylori. Infection eradication reduces levels of both factors to those of controls. One major pathogenic mechanism for gastric mucosal hyperproliferation and possibly carcinogenesis related to H. pylori may be the over expression of EGF and increased receptor density of EGFR on gastric mucosal cells.

Endocytosis of fluorescent microspheres by human oesophageal 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 microns 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 micron 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 from normal biopsy specimens (p = 0.015). In conclusion, endocytosis occurs in oesophageal epithelial cells and is increased in inflammation.

Review article: factors protecting the oesophagus against acid-mediated injury

Reflux of gastric acid and pepsins into the lower oesophagus causes symptoms such as heartburn and nausea, and tissue injury leading to erosive oesophagitis and stricture formation. This article reviews the mechanisms involved in protecting the oesophagus against acid-mediated injury, including the role of the lower oesophageal sphincter, secondary oesophageal peristalsis and swallowed saliva. The oesophageal mucosa has inherent abilities to resist acid damage, and recent data from three laboratories suggest a secretory function with local production of bicarbonate and mucus responsive to local acidification. The evidence for these putative oesophageal defence mechanisms is discussed.