Neonatal enteroids absorb extracellular vesicles from human milk-fed infant digestive fluid

Area of Science:

• Biochemistry
• Cell Biology
• Neonatal Nutrition

Background:

• Human milk extracellular vesicles (HMEVs) show preclinical promise for enhancing intestinal function and reducing inflammation.
• The survival and absorption of HMEVs within the neonatal human digestive system remain uncharacterized, limiting their therapeutic and nutritional applications.

Approach:

• Developed an extracellular vesicle (EV) isolation pipeline from human milk and neonatal digesta.
• Utilized density-gradient ultracentrifugation, filtration, and precipitation methods for EV purification.
• Validated EVs using electron microscopy, western blotting, nanoparticle tracking analysis, resistive pulse sensing, and super-resolution microscopy.
• Assessed EV uptake in human neonatal enteroids.

Key Points:

• Isolated and validated EVs from both human milk (HMEVs) and neonatal digesta (dEVs), confirming typical EV morphology and surface markers (CD81, CD9).
• HMEVs and dEVs were depleted of specific milk proteins like β-casein and lactalbumin but retained others, such as BTN1A1.
• Demonstrated rapid uptake of dEVs by neonatal intestinal epithelial cells (IECs) in vitro, partly via clathrin-mediated endocytosis.

Conclusions:

• Extracellular vesicles can be successfully isolated from neonatal digestive fluids.
• Neonatal intestinal epithelial cells actively absorb these digesta-derived extracellular vesicles (dEVs).
• These findings suggest HMEVs can potentially survive neonatal digestion and be absorbed, opening avenues for infant nutrition and therapeutic strategies.