Cytokinetics and histogenesis of cultured hamster tracheal epithelium : effects of vitamin A and cigarette smoke condensate

The studies reported in this thesis primarily deal with the influence of vitamin A (all-trans retinol) and cigarette smoke condensate on cellular proliferation, and differentiation and intercellular communication in tracheal epithelium. The experiments were carried out with Syrian Golden hamster tracheas and primary tracheal epithelial cells maintained in serum-free, hormone-supplemented media. All-trans retinol was used to regulate cellular proliferation and differentiation, whereas cigarette smoke condensate was used to induce alterations.

This thesis is divided into three parts: General introduction (Chapters 1 and 2), Experiments (Chapters 3-8) and Conclusion (Chapters 9 and 10).

In Chapters 1 and 2 of the current knowledge of retinoids, tracheal epithelium, intermediate filaments, intercellular communication and in vitro model systems with tracheal epithelium are summarized.

In Chapters 3 and 4 the effects of all-trans retinol and cigarette smoke condensate on vitamin A-depleted hamster tracheal epithelium in organ culture are discussed with emphasis on cellular proliferation and differentiation.

Chapter 5 deals primarily with the role of proliferating basal cells in untreated tracheal epithelium, and in vitamin A-depleted tracheal epithelium treated with a physiological all-trans retinol concentration. The effects on tracheal epithelial cells were observed by means of monoclonal antibodies against various keratins. The information obtained in this Chapter was used to study the effects of cigarette smoke condensate and vitamin A depletion on intermediate filament expression patterns in tracheal epithelium (Chapter 6).

In Chapter 7 experimental evidence is given that ciliated tracheal epithelial cells can divide in hamster tracheal organ cultures treated with all-trans retinol or cigarette smoke condensate.

Chapter 8 deals with the role of vitamin A (all-trans retinol and retinoic acid) and cigarette smoke condensate on dye-coupled intercellular communication between primary hamster tracheal epithelial cells.

In Chapters 9 and 10 a summary of the results is given with concluding remarks in both English and Dutch.