Role of Epidermal Growth Factor in Growth and Regeneration of Adult Human Airway Epithelium

1991 Fiscal Year Final Research Report Summary

• Project/Area Number: 02670139
• Research Category: Grant-in-Aid for General Scientific Research (C)
• Allocation Type: Single-year Grants
• Research Field: Human pathology
• Research Institution: Yokohama City University, School of Medicine
• Principal Investigator: KITAMURA Hitoshi Yokohama City University, School of Medicine, Associate Professor, 医学部, 助教授 (20094302)
• Co-Investigator(Kenkyū-buntansha): INAHAMA Yoshiaki Yokohama City University, School of Medicine, Research Instructor, 医学部, 助手 (10184730) ; ITO Takaaki Yokohama City University, School of Medicine, Assistant Professor, 医学部, 講師 (70168392)
• Project Period (FY): 1990 – 1991
• Keywords: Adult human / Airway epithelial cells / Regeneration / Epidermal growth factor / Epidermal growth factor receptor / Immunohistochemistry / AMeX method

Research Abstract

In order to clarify the role of epidernal growth factor(EGF)in proliferation and differentiation of the airway epithelial cells in adult humans, we investigated the expression of EGF-receptor(EGFR)using monoclonal antibodies against EGFR by the method of immunohistochemistry, and employing the ANeX method(Sato et al., 1986)for tissue preparation. Firstly, peripheral lung tissue and bronchial tissue as well, obtained from the surgically respected lungs from patients with lung carcinoma, were fixed in cold acetone and subsequently prepared for histological sectionings by the AMeX method. The results showed that there was no positive staining for EGFR in the bronchial surface epithelium, bronchial glandular cells, bronchiolar epithelium, and alveolar lining cells. In the hyperplastic or metaplastic -epithelia, i. e. basal cell hyperplasia and epidersoid netapla, sia in the bronchus, and alveolar epithelial cell hyperplasia and bronchiolization in the fibrosed lung, there also was no positivity for EGFR. Secondly, we examined the expression of EGFR in the regenerating distal airway epithelial cells which were experimentally produced in the human lung tissue xenotransplanted into nude lice. There was no positive staining for EGFR at any stage of regeneration from one week through six weeks after the transplantation.
We conclude that EGFR is not expressed, at least at the immunohistochemically detectable levels, by the airway epithelial cells in adult humans, not only in the stable state in terms of cell kinetics, but also in the states where the epithelial cells are stimulated to proliferate, such as regeneration, reactive hyperplasia or metaplasia.