Noninvasive assessment of human embryo nutrient consumption as a measure of developmental potential.
OBJECTIVE
To determine the relationship between blastocyst development and morphology and embryo metabolism.


METHODS
Noninvasive assessment of carbohydrate uptake and ammonium production by individual embryos.


METHODS
Private assisted reproductive technology unit.


METHODS
Patients donated, with consent, cryopreserved pronucleate embryos and noncryopreserved blastocysts.


METHODS
Culture of 60 thawed pronucleate embryos in sequential media to the blastocyst stage with concomitant noninvasive analysis of embryo metabolism and analysis of 13 blastocysts from noncryopreserved embryos.


METHODS
Pyruvate and glucose consumption as well as blastocyst formation and quality.


RESULTS
Pyruvate and glucose uptakes on day 4 were significantly higher by embryos that went on to form blastocysts than by embryos that failed to develop to the blastocyst stage. Glucose uptakes were greatest in those blastocysts of highest grade, whereas pyruvate uptakes were similar irrespective of blastocyst grade, indicating that glucose is the more important nutrient for the human blastocyst. Among blastocysts of the same grade from the same patient, there was considerable spread of glucose consumption, indicating that glucose consumption may be of use in identifying blastocysts for transfer. Ammonium production by individual embryos was also measured, reflecting amino acid transamination and use by the human embryo.


CONCLUSIONS
The ability to identify in culture the embryo with the highest developmental potential will facilitate the move to single-embryo transfers.
Gardner
D K
DK
Colorado Center for Reproductive Medicine, Englewood, Colorado 80110, USA. dgardner@colocrm.com
Lane
M
M
Stevens
J
J
Schoolcraft
W B
WB
D001755:Blastocyst / Q000378:metabolism* / Q000502:physiology; D015925:Cryopreservation; D005314:Embryonic and Fetal Development / Q000502:physiology*; D005260:Female; D005307:Fertilization in Vitro / Q000379:methods*; D005947:Glucose / Q000032:analysis / Q000378:metabolism; D006801:Humans; D008297:Male; D008856:Microscopy, Fluorescence; D011247:Pregnancy; D019289:Pyruvic Acid / Q000032:analysis / Q000378:metabolism; D000644:Quaternary Ammonium Compounds / Q000032:analysis / Q000378:metabolism
D000644:Quaternary Ammonium Compounds; D019289:Pyruvic Acid; D005947:Glucose