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

Abstract

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 β-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.