Expression of vascular endothelial growth factor mRNA in human preimplantation embryos derived from tripronuclear zygotes.

OBJECTIVE To detect the expression of vascular endothelial growth factor (VEGF) mRNA and/or secretion of VEGF protein by human preimplantation embryos. DESIGN Human preimplantation embryos not suitable for uterine transfer were examined for beta-actin and VEGF mRNA expression. Culture media from normally fertilized and developing preimplantation embryos were assessed for VEGF protein secretion. SETTING Clinics and academic research laboratories at the Departments of Obstetrics and Gynecology at the Stanford University, Palo Alto, California and the Heinrich-Heine-University, Düsseldorf, Germany. PATIENT(S) Couples undergoing IVF by intracytoplasmic sperm injection for various reasons. INTERVENTION(S) Six unfertilized oocytes and 33 pathologically fertilized (tripronucleic, 3PN) preimplantation embryos were examined for VEGF mRNA expression, and 16 embryos were examined for VEGF protein secretion. MAIN OUTCOME MEASURE(S) Embryonic expression of VEGF mRNA and VEGF protein as determined by reverse transcription (RT)/nested polymerase chain reaction (PCR) and ELISA. RESULT(S) VEGF mRNA and protein could not be detected in unfertilized oocytes. However, 30/33 preimplantation embryos did express VEGF mRNA (11/12 10-to-16-cell embryos, 3/4 morulae, 11/12 early blastocysts, 5/5 hatched blastocysts). The VEGF protein level was below the sensitivity of the ELISA. CONCLUSION(S) Production of VEGF may give the embryo the ability to induce neoangiogenesis at the implantation site, thus creating an environment necessary for its survival.