In Vitro and In Vivo Development of Horse Cloned Embryos Generated with iPSCs, Mesenchymal Stromal Cells and Fetal or Adult Fibroblasts as Nuclear Donors.
Authors: Olivera Ramiro, Moro Lucia Natalia, Jordan Roberto, Luzzani Carlos, Miriuka Santiago, Radrizzani Martin, Donadeu F Xavier, Vichera Gabriel
Journal: PloS one
Summary
# Editorial Summary Equine cloning remains an attractive option for preserving genetic material from high-value animals, yet the consistently low success rates of nuclear transfer procedures have limited its practical application. Researchers compared the effects of timing between cell fusion and embryo activation (spanning <1 hour to 2–3 hours) alongside three different nuclear donor cell types—induced pluripotent stem cells, mesenchymal stromal cells from umbilical cord tissue, adult fibroblasts, and fetal fibroblasts—using both in vitro development and recipient mare pregnancies as outcome measures across 4681 fusion events. A 2–3 hour interval between fusion and activation roughly doubled blastocyst production rates compared to shorter intervals (11.5% versus 5.2% at <1 hour), and umbilical cord-derived mesenchymal stromal cells consistently outperformed adult fibroblasts for blastocyst development (15.6% versus 9.3%); notably, fetal fibroblasts proved the only donor type capable of generating viable foals in this series, yielding two healthy animals where other cell types failed. Whilst induced pluripotent stem cells—despite their theoretical pluripotency advantages—produced no viable embryos, the overall success generated 24 healthy foals from 29 born animals, suggesting that optimising activation timing and judicious selection of donor cell source, particularly using fetal or umbilical-derived cells rather than adult fibroblasts, could meaningfully improve the efficiency of equine cloning programmes used for genetic preservation.
Read the full abstract on PubMed
Practical Takeaways
- •For equine cloning operations, maintain a 2-3 hour window between cell fusion and embryo activation to optimize success rates
- •UC-MSCs represent a more efficient nuclear donor cell source than traditional adult fibroblasts, potentially improving cloning program outcomes
- •While fetal fibroblast lines may be logistically challenging to establish, they appear superior for producing viable cloned foals and should be considered when cloning high-value genetics
Key Findings
- •A 2-3 hour interval between cell fusion and activation yielded the highest blastocyst production (11.5%) and pregnancy rates (9.5%) compared to shorter intervals (<1h: 5.2%, 1-2h: 5.6%)
- •Umbilical cord-derived mesenchymal stromal cells (UC-MSCs) produced superior blastocyst rates (15.6%) compared to fetal fibroblasts (8.9%) or adult fibroblasts (9.3%)
- •Induced pluripotent stem cells (iPSCs) generated no blastocyst-stage embryos, and injection of pluripotency-inducing genes did not improve outcomes over adult fibroblast controls
- •24 of 29 foals born were healthy; viable offspring were produced only with fetal fibroblast nuclear donors despite similar pregnancy rates across donor types