Reliable single sperm cryopreservation in Cell Sleepers for azoospermia management

Area of Science:

• Reproductive Medicine
• Cryobiology
• Infertility Research

Background:

• Conventional sperm cryopreservation is less effective with samples containing fewer than hundreds of spermatozoa.
• Severe male factor infertility, including obstructive azoospermia, nonobstructive azoospermia, and cryptozoospermia, often yields very low sperm counts.
• Limited sperm availability poses challenges for assisted reproductive technologies.

Purpose of the Study:

• To evaluate the reproductive outcomes of using spermatozoa cryopreserved in novel Cell Sleepers.
• To assess the efficacy of Cell Sleepers for patients with severe male factor infertility and limited sperm retrieval.
• To determine if Cell Sleepers can eliminate the need for same-day sperm retrieval during oocyte retrieval.

Main Methods:

• A case series of 12 intracytoplasmic sperm injection (ICSI) cycles using spermatozoa frozen in Cell Sleepers.
• Cell Sleepers, devices for freezing individual spermatozoa in microdroplets, were used.
• Spermatozoa from 12 men with severe male factor infertility (obstructive azoospermia, non-obstructive azoospermia, cryptozoospermia) were cryopreserved.

Main Results:

• A total of 304 spermatozoa were frozen, with 179 used for ICSI.
• Fertilization rate was 65.9% (118/179), with no total fertilization failures.
• Clinical pregnancy rate was 58.3% (7/12), with four pregnancies progressing beyond 20 weeks gestation.

Conclusions:

• Cryopreservation of spermatozoa using Cell Sleepers is effective and uncomplicated for men with severe male factor infertility.
• Cell Sleepers expand the range of sperm samples that can be successfully cryopreserved.
• This method eliminates the need for urgent sperm retrieval on the day of oocyte collection, simplifying the ICSI process.