O-148 Sperm Aminopeptidase N as a predictive biomarker of blastocyst development and embryo viability

Study question

To evaluate human sperm APN as a prognostic factor for determining high-quality embryos.

Summary answer

The human sperm APN has the potential to become new molecular prognostic biomarker for having high-quality and viable embryos.

What is known already

Prognosis and diagnosis of male fertility is one of the major concerns in reproductive medicine. Approximately 30%-40% of men with otherwise normal fertility parameters are still unable to achieve pregnancy. The predictive clinical value of a semen analysis to identify fertile or infertile males is limited; therefore, new sperm diagnostic or prognostic methodologies are urgently required. Sperm Aminopeptidase N (APN) may be a relevant molecular marker due to its high concentration in sperm cells and its role in sperm physiology, such as motility, acrosome reaction, and embryo development.

Study design, size, duration

A prospective study that involves a total of 81 couples and 611 embryos who underwent oocyte-donation cycles at the Clínica IVI Bilbao (Spain) between September 2014 and July 2015.

Participants/materials, setting, methods

This study was set in an assisted reproduction unit and in an academic research laboratory. All semen samples were examined and classified following WHO guidelines. Spermatozoa were isolated from semen on discontinuous colloidal silica gradient (45%-90%) technique. Embryo quality and development were determined according to the Spanish Association of Reproduction Biology Studies (ASEBIR) criteria. Flow cytometry analyses of quantitative and semi-quantitative sperm human APN levels.

Main results and the role of chance

The obtained results proved that the most evolved and viable blastocysts were associated with low sperm APN levels. Expanding, expanded, hatching/hatched and viable blastocysts come from semen samples which showed lower APN levels than early blastocysts, blocked and non viable blastocyst. The cumulative probability of having more evolved blastyocysts increased 1.38-fold at day 5 and 1.98-fold at day 6 of embryo development as well as the likelihood of having viable embryo increased 1.48-fold when semen samples with low APN levels are used during the ICSI technique.

Limitations, reasons for caution

Data obtained from a single Fertility Clinic. A multi-centrum study will be required.

Wider implications of the findings

The human sperm APN has the potential to become new molecular prognostic biomarker for having high-quality embryos that could help to diagnose male infertility, especially when seminal parameters are close to the threshold values.

Trial registration number

Not applicable