Dallas M. Hyde

The remodelled tracheal basement membrane zone of infant rhesus monkeys after 6 months of recovery

Background In previous studies, we showed that repeated exposure to (1) house dust mite allergen (HDMA) (Dermatophagoides farinae) caused thickening of the basement membrane zone (BMZ) and (2) HDMA+ozone (O3) caused depletion of BMZ perlecan and atypical development of BMZ collagen (irregular thin areas<2.0 μm in width).

Asthma: a comparison of animal models using stereological methods

Asthma is a worldwide health problem that affects 300 million people, as estimated by the World Health Organization. A key question in light of this statistic is: “what is the most appropriate laboratory animal model for human asthma?” The present authors used stereological methods to assess airways in adults and during post-natal development, and their response to inhaled allergens to compare rodents and nonhuman primates to responses in humans. An epithelial–mesenchymal trophic unit was defined in which all of the compartments interact with each other. Asthma manifests itself by altering not only the epithelial compartment but also other compartments (e.g. interstitial, vascular, immunological and nervous). All of these compartments show significant alteration in an airway generation-specific manner in rhesus monkeys but are limited to the proximal airways in mice. The rhesus monkey model shares many of the key features of human allergic asthma including the following: 1) allergen-specific immunoglobulin (Ig)E and skin-test positivity; 2) eosinophils and IgE+ cells in airways; 3) a T-helper type 2 cytokine profile in airways; 4) mucus cell hyperplasia; 5) subepithelial fibrosis; 6) basement membrane thickening; and 7) persistent baseline hyperreactivity to histamine or methacholine. In conclusion, the unique responses to inhaled allergens shown in rhesus monkeys make it the most appropriate animal model of human asthma.

Epithelial Cells of the Bronchiole

Abstract This chapter focuses on the epithelium of the distal conducting airways, or bronchioles, with emphasis on the area of transition between conducting airways and the gas-exchange area. The bronchiolar region has a substantial variation from one species of mammal to the next. This variability includes the microenvironment in which epithelial cells are found, particularly the zone of transition between bronchiolar, non-gas exchange regions and the alveolar gas-exchange regions. There is also considerable interspecies variability in the general composition of the bronchiolar epithelium. The principal alterations involve the distribution, number, and percentage of the population that is nonciliated cells. In addition, there is substantial variability in the composition and differentiated expression of the nonciliated epithelial population in this region.