Amino acids promote human blastocyst development in vitro

Area of Science:

• Reproductive biology
• Developmental biology
• In vitro fertilization (IVF)

Background:

• Amino acid supplementation is known to improve preimplantation embryo development in various species.
• Optimizing culture media is crucial for successful in vitro fertilization (IVF) outcomes.

Purpose of the Study:

• To investigate the impact of amino acid supplementation on human embryo development from the 2- to 4-cell stage to blastocyst.
• To compare the efficacy of different serum-free, chemically defined sequential media on human embryo development.

Main Methods:

• A randomized study involving 129 human embryos cultured in three different serum-free sequential media.
• Media included Earle's balanced salt solution (EBSS) with glutamine (Gln), EBSS with Gln and non-essential amino acids (AA), and a commercial medium (K-SCIM).
• Blastocyst cell counts (trophectoderm, inner cell mass), mitoses, and dead cells were analyzed on day 6.

Main Results:

• Blastocyst development rates were similar across all three media.
• Amino acid supplementation (Earle's+AA and K-SCIM) significantly increased total blastocyst cell numbers compared to Earle's+Gln (P = 0.005).
• This increase in cell number was observed in both trophectoderm and inner cell mass lineages, with a significant reduction in the dead cell index for Earle's+AA (P = 0.047).

Conclusions:

• Supplementation with a combination of amino acids significantly improves human blastocyst cell allocation and quality.
• Chemically defined, serum-free media containing amino acids can effectively support human embryo development in vitro.
• These findings have implications for optimizing IVF culture protocols to enhance reproductive success.