Assistant Professor Baylor College of Medecine Houston, Texas, United States
Abstract: Congenital malformations affect approximately 1.9 per 1000 live births globally. Prenatal surgical repair using regenerative strategies has shown promise in reducing the severity of these conditions, but mid-pregnancy in utero interventions remain invasive for both the mother and fetus. To address this, we are exploring less invasive approaches by leveraging mesenchymal stem cells derived from amniotic fluid (AF-MSCs) to create a pro-regenerative environment within the amniotic cavity, promote tissue homeostasis, and facilitate repair. We also investigated extracellular vesicles (EVs) as stable, reproducible, and reconfigurable alternatives to cell-based therapies, aiming to overcome the challenges of stem cell treatments while retaining therapeutic efficacy. Biodistribution studies following intraperitoneal administration of EVs in female mice demonstrated targeted delivery to the uterus and yolk sac, with no observed toxicity in the dams throughout gestation and no significant changes in fetal viability. These findings were observed in a well-established mouse model (SWV/Fnn strain), which is highly susceptible to drug-induced toxicity and neural tube defects. Continuous administration of EVs (10e9/dose) during neurulation (E5.5–E9.5) in a spina bifida model (Fkbp8 knockout) resulted in a significant reduction in lesion size (3mm) compared to PBS-treated controls (5–8mm), along with visible vertebrae closure at the last thoracic and lumbar levels. When used as RNA therapeutics, EVs maintained cargo stability, demonstrating long-term expression of loaded mRNA both in vitro and in an ex vivo whole embryo culture system. This confirms that mRNA functionality is preserved in more complex systems, as EVs successfully cross the yolk sac, reach the embryo, and restore gene function. These findings suggest that AF-MSC-derived EVs represent a promising, minimally invasive and reconfigurable precision medicine approach, with potential for further development in the in utero treatment of congenital malformations.
Funding Source: Research reported in this publication is supported by the Eunice Kennedy Shriver National Institute of Child Health & Human Development of the National Institutes of Health under Award Number R01HD113702.
