Poster Presentation & Flash Talk 46th Annual Meeting of the Fetal and Neonatal Physiological Society 2019

Human amnion cell-derived extracellular vesicles in the treatment of bronchopulmonary dysplasia (#105)

Dandan Zhu 1 2 , Amina Maleken 2 , Sinnee Lau 2 , Siow Chan 1 2 , Joanne Mockler 1 2 , Daniel Chambers 3 4 , Kristen Leeman 5 6 , Carla Kim 6 , Euan Wallace 1 2 , Rebecca Lim 1 2
  1. Obstetrics and gynaecology, Monash Medical Centre, Melbourne, VIC, Australia
  2. Hudson Institute of Medical Research, Clayton, VIC, Australia
  3. Queensland Lung Transplant Service, The Prince Charles Hospital, Brisbane
  4. 5School of Medicine, The University of Queensland, Brisbane, Queensland, Australia
  5. Newborn Medicine, Department of Pediatrics, Children’s Hospital Boston, Harvard Medical School, Boston, MA, United States
  6. Children’s Hospital Boston Stem Cell Program, Department of Genetics, , Harvard Medical School and Harvard Stem Cell Institute, Boston, MA, United States

Background: We previously showed that human amnion epithelial cells (hAECs) are a viable source of cell therapy for established bronchopulmonary dysplasia (BPD). This work has led to a first-in-human clinical trial in babies with established BPD. Here we sought to assess the therapeutic potential of hAEC-derived EVs (hAEC-EVs) in an experimental model of BPD.

 Methods: Lipopolysaccharide was introduced to C57bl6 mouse fetuses intra-amniotically at E16 prior to exposure to 65% oxygen (hyperoxia) at birth. hAEC-EVs were injected intravenously on postnatal day (PND) 4. One cohort of mice were culled on either postnatal day PND7 or PND14, while another cohort were kept in hyperoxia until PND 28, following which they were recovered under normoxia conditions for a further 2 weeks for cardiovascular assessment.

Results: The isolated hAEC-EVs had distinct cup shaped morphology with average size of 80-140nm, and ALIX, Grp94 and HLA-G were expressed in EVs. In the mouse model of experimental BPD, hAEC-EV administration improved tissue-to-airspace ratio and septal crest density in a dose-dependent manner. hAEC-EVs reduced the levels of inflammatory cytokines such as IL-1β and TNF-α on PND7. The improvement of lung injury was associated with the increase of the percentage of type II alveolar cells (AT2s). Surprisingly, neonatal hAEC-EV delivery reduced airway hyper-responsiveness, mitigated pulmonary hypertension and prevented right ventricle hypertrophy that associated with BPD-like lung injury at week 6. These improvements persisted till week 10. All these observations showed that HAEC-EVs mitigate the BPD lung injury through decreasing inflammation, activating local AT2 niche and reversing pulmonary artery remodeling.

Conclusions: hAEC-derived EVs improved lung structure and reduced lung inflammation in a manner similar to that achieved using hAECs. EVs repaired lung injury partly through the activation of local stem/progenitor cells. Furthermore, hAEC-EV administration had long term benefit in improving lung function, preventing pulmonary hypertension and right ventricle hypertrophy.