Oral Presentation Australia and New Zealand Society for Extracellular Vesicles Conference 2025

Characterisation of human milk extracellular vesicles in a cohort of New Zealand mothers (127255)

Fang Liu 1 , Mark H Vickers 1 , Benjamin B Albert 1 , Hui Hui Phua 1 , Vidit V Satokar 1 , Shikha Pundir 1 , Cherie Blenkiron 2 3 4 , Farha Ramzan 1
  1. Liggins Institue, University of Auckland, Auckland , New Zealand
  2. Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
  3. Hub for Extracellular Vesicle Investigations, University of Auckland, Auckland, New Zealand
  4. Department of Molecular Medicine and Pathology, University of Auckland , Auckland, New Zealend

Background: Extracellular vesicles (EVs) carry cargo containing biological components such as RNA, lipids and proteins. EVs are widely found in various body fluids, including human milk (HM). HM-EVs are reported to influence infant development and their long-term health. Despite the emergence of EVs as important bioactive compounds in HM, they are not fully characterised.

Aims: To characterise HM-EVs in overweight/obese mothers who participated in a randomised controlled trial of fish oil (FO) supplementation during pregnancy and lactation and investigate the effects of different lactation stages and FO supplementation on the composition of HM-EVs.

Methods: Archived HM samples from 56 mothers (n=25 in the FO group; n=31 in the olive oil group (control)) collected at 2 wk (transitional HM) and 3 mo (mature HM) postpartum respectively were included from the FO in Pregnancy Trial. HM-EVs were isolated using multimodal chromatography (CaptoTM core) and were examined for concentration, size and total protein content. Changes in the HM-EV profiles of small RNAs and lipids will also be characterised using RNA sequencing and mass spectrophotometry, respectively.

Results: EVs in transitional HM had higher concentration (3.5E+11±1.3E+11 particles/mL HM vs 2.3E+11±1.8E+11 particles/mL HM; P < 0.001), larger diameter (223.3±19.2 nm vs 206.8±14.1 nm; P < 0.001) than those in mature HM, but similar total protein content. FO supplementation did not influence the concentration, size, or total protein content of HM-EVs.

Conclusion: EV concentration and size varied across the two different lactation stages. Ongoing work will further explore how lactation stage and FO supplementation affect HM-EV small RNA and lipid profiles.