Acid ceramidase improves the quality of oocytes and embryos and the outcome of in vitro fertilization

Abstract

A major challenge of assisted reproduction technologies (ARTs) is to mimic the natural environment required to sustain oocyte and embryo survival. Herein, we show that the ceramide-metabolizing enzyme, acid ceramidase (AC), is expressed in human cumulus cells and follicular fluid, essential components of this environment, and that the levels of this enzyme are positively correlated with the quality of human embryos formed in vitro. These observations led us to develop a new approach for oocyte and embryo culture that markedly improved the outcome of in vitro fertilization (IVF). The addition of recombinant AC (rAC) to human and mouse oocyte culture medium maintained their healthy morphology in vitro. Following fertilization, the number of mouse embryos formed in the presence of rAC also was improved (from approximately 40 to 88%), leading to approximately 5-fold more healthy births. To confirm these observations, immature bovine oocytes were matured in vitro and subjected to IVF in the presence of rAC. Significantly more high-grade blastocysts were formed, and the number of morphologically intact, hatched embryos was increased from approximately 24 to 70%. Overall, these data identify AC as an important component of the in vivo oocyte and embryo environment, and provide a novel technology for enhancing the outcome of assisted fertilization. Eliyahu, E., Shtraizent, N., Martinuzzi, K., Barritt, J., He, X., Wei, H., Chaubal, S., Copperman, A. B., Schuchman, E. H. Acid ceramidase improves the quality of oocytes and embryos and the outcome of in vitro fertilization.

Construction of Conditional Acid Ceramidase Knockout Mice andin vivoEffects on Oocyte Development and Fertility

“…Ceramide also has been shown to play a central role in the age-related acceleration of apoptosis in the female germline [10, 11]. In our previous publication [5], we showed that in human oocytes AC co-localizes with membranes, the meiotic spindle, and DNA, thus supporting its potential role in preventing cell cycle arrest. Recent reports also have shown that apoptosis in the ovaries of several species can be prevented by S1P, a downstream product of AC activity [11, 12, 29].…”

“…We have further shown by immunohistochemical, western blotting and enzymatic activity assays that AC is expressed in human and murine oocytes and/or follicular fluid, and that its expression levels decline during oocyte culture. In addition, supplementation of AC into media improved the survival rates and quality of oocytes and embryos grown in vitro , as well as embryo development in vivo after implantation [5]. …”

The molecular medicine of acid ceramidase

“…As noted above, observations on the early embryonic lethality of the complete AC knockout mouse led to the use of rhAC to enhance the outcome of in vitro fertilization (IVF) (Eliyahu et al, 2010). Supplementation of mouse IVF culture media with rhAC resulted in approximately twofold more embryos than obtained using standard culture conditions.…”

Lysosomal Lipid Storage Diseases

“…AC knockout mice do not survive beyond the 2-cell stage and undergo apoptotic death (Eliyahu et al 2007). Recent findings show that AC improves the quality of oocytes and embryos and the outcome of in vitro fertilization (Eliyahu et al 2010).…”