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Characterising and assessing the baseline functionality of the airway epithelium in preterm infants

Ang, Sherlynn (2017) Characterising and assessing the baseline functionality of the airway epithelium in preterm infants. Honours thesis, Murdoch University.

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PDF - Whole Thesis
Embargoed until March 2019.

Abstract

Introduction & Aims:
Preterm birth rates have risen to over 8% in Australia. The lungs are one of the last organs to develop and therefore, the preterm lung is immature at birth. As effects of premature birth on airway cell function are unknown, we investigated whether preterm nasal epithelial cells (NECs) are inherently different to cells of full-term born infants.

Methods:
The NECs were obtained via brushing nine preterm born infants (5 males, average gestational age at birth 26.6 ± 2.4 weeks) aged 1.7 years corrected age and nine full-term born infants (5 males) aged 2.3 ± 0.2 years. Submerged monolayer cultures were generated and RNA, protein, supernatant and cytospins were collected. Cell lineage markers were analysed at gene (qPCR) and protein (immunocytochemistry, Western blot) level. Cytokines were measured via ELISA. Two functional assays were performed; wound repair by monolayer culture and transepithelial permeability assay by differentiated, air-liquid interface culture.

Results:
Preterm NEC were morphologically similar to full-term NEC as monolayer and ALI cultures. Compared to full-term NEC, preterm NECs had significantly higher CK-19 gene expression at passage 1 (1.95 ± 0.51 vs 0.78 ± 0.17; p<0.05) but not CK-5 and vimentin expression. However, CK-19 protein was lower in preterm NECs. Cytokine differences were restricted to higher IL-8 by preterm NECs at passage 3 (31587 ± 3933 vs 15413 ± 5960 pg/mL; p<0.05). Interestingly, transepithelial permeability was significantly lower in preterm children for both particle sizes used (4 kDA: 59.75 vs 324; 20 kDA: 43.26 vs 415.9, p<0.05). Wound repair of preterm NEC was also lower (72 hours: 62.10 vs 100%, p<0.05).

Conclusion:
Preterm and full-term NECs morphology, gene, protein and cytokine expression were predominantly comparable at baseline. However, interestingly functional differences also existed. Preterm NECs could be used to model mechanisms of preterm respiratory disease.

Publication Type: Thesis (Honours)
Murdoch Affiliation: School of Veterinary and Life Sciences
Supervisor: Kicic, Anthony, Garratt, Luke, Simpson, Shannon and Currie, Andrew
URI: http://researchrepository.murdoch.edu.au/id/eprint/39878
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