Reconstruction of native cellular microanatomy in a novel bioengineered full thickness human nasal mucosal construct

Bioengineered tissues offer vital platforms capable of fundamental research, screening interventions and reducing the use of animals in scientific research. However, their predictive accuracy is dependent upon how closely their structure and function resemble their native counterpart. In this study, we present a novel in vitro engineered construct representative of the human nasal mucosa, consisting of both stromal and epithelial compartments. Communication between the stroma and the overlying epithelium is an essential factor involved in tissue development and homeostasis yet is often lacking in the majority of published tissue constructs. Described is the construction of a pseudostratified epithelium consisting of an organised heterogeneous cell population consistent with the respiratory region of the nasal mucosa that forms on a stromal foundation populated with tissue-specific fibroblasts and endogenous extracellular matrix. In addition, for the first time, we provide an extensive ultrastructural analysis of a bioengineered nasal tissue using both scanning and transmission electron microscopic techniques. This in-depth characterisation revealed microanatomical hallmarks consistent with the native tissue, including motile cilia, mucin secretions, intercellular junctions, dynamic basement membrane, microvilli and glycocalyx. Given each of these features play pivotal physiological roles in the specialised functions of the respiratory epithelium, their presence in vitro lends itself to tissue equivalents with enhanced physiological relevance and greater predictive accuracy. In summary, we present a highly characterised in vitro nasal mucosal construct that accurately reflects native microanatomy. Such technology will be of value to a wide range of applications, most notably, undertaking basic research and in vitro pharmaceutical screening, of which nasal mucosal models have become increasingly applicable due to the popularity of intranasal drug and vaccine delivery methods.