Physiological Intracytoplasmic Sperm Injection (PICSI) is a scientific technique used in Intracytoplasmic Sperm Injection (ICSI)– a specialized form of In Vitro Fertilization (IVF) – to assist the embryologist in the selection of sperm.
The PISCI sperm selection device is a polystyrene culture dish with three microdots of hyaluronan attached to the interior bottom, The dish is sterile, and non-toxic to embryos and is used as an additional step in the selection of sperm for ICSI.
Hyaluronan is a main component of the cumulus covering of the ooctye (egg), the head of a mature sperm carries a hyaluronan-specific receptor that allows mature sperm to bind to hyaluronan.
In contrast, immature sperm do not bind, mature sperm exhibit high DNA integrity and normal frequency of chromosomal aneuploidies, provides paternal contribution to the zygote comparable to that of sperm selected by the zona pellucida during natural fertilization.
Principle of the device:
Sperm in vivo (in nature) encounters Hyaluronan in the cervical mucus and in the cumulus matrix surrounding the oocyte.
Penetration of the cervical mucus and cumulus matrix by the sperm in vivo are critical elements in successful fertilization and subsequent embryo implantation (when the fertilized egg attaches into the lining of the female’s uterus), Hyaluronan is vital in this interaction.
During ICSI, motile sperm are selected for injection on the basis of their morphology; it does not reflect the genomic integrity of the sperm and its ability to provide the best paternal contribution to the zygote and does not necessarily reflect the functionality of the sperm or its ability to fertilize an egg (oocyte). The PICSI dish provides a functional test.
The test is based on the ability of sperm to bind to Hyaluronan (HA) – hydrogel mimicking the natural binding of mature sperm to oocytes in the female, PICSI takes advantage of this naturally occurring encounter.
Therefore, the PICSI device provides a means to select mature sperm based on their ability to bind hyaluronan gel in the dish mimicking the natural binding of mature sperm to the cumulus which is an important selective step in natural fertilization.
Research has proven that hyaluronan-bound PICSI-selected sperms are, in the vast majority of cases, more mature, exhibit less DNA damages, and have fewer chromosomal aneuploidies. PICSI technique improves pregnancy rates and reduces the number of IVF miscarriages.
Indications for PICSI sperm selection device:
- Patients with high sperm DNA fragmentation.
- Previous history of poor embryo development day- 3 to day-5.
- Previous history of low or poor fertilization.
- Repeated implantation failure.
- High miscarriage rate.
- reduced sperm morphology.
- reduced sperm motility
- Low fertilization with ICSI has occurred
- The woman is over 38 years old
PICSI increases the success rate by approximately 20% because it enables us to select and introduce a sperm to the oocyte based on its functional quality. This method works on the same principle by which sperms are selected in a woman’s body within the natural fertilization process.