Effects of taurine on human embryo development in vitro.

Glutamine and taurine are reported to be beneficial for mouse embryo development in vitro, and we have recently shown that glutamine improves human blastocyst formation in vitro. This randomized study compared the development of supernumerary human embryos in the presence of 1 mmol/l glutamine and/or 5 mmol/l taurine from the 2-4-cell stage to the blastocyst stage. Blastocyst development and cell numbers were similar in the presence of glutamine or taurine: 52.6% and 58.3% of the embryos reached the blastocyst stage, respectively. Pyruvate uptake was similar in the presence of glutamine or taurine throughout development, as was lactate production after the 8-cell stage. Before this stage, lactate production was 4-fold higher in the presence of taurine (P < 0.001). The proportion of embryos reaching the blastocyst stage was similar with glutamine alone or with glutamine and taurine (62.5% and 47.2% respectively), as were the blastocyst cell numbers (63.0 +/- 4.6 and 61.0 +/- 5.1 respectively). In conclusion, taurine supports development of 2-4-cell human embryos to the blastocyst stage, although it does not further augment the beneficial effects of glutamine.