IVF Laboratory Procedures IMSI
Selected Sperm Microinjection with High Microscopic Magnification
Compared to standard in vitro fertilization and microinjection applications, this technique gives the opportunity to perform the morphological analysis of sperm at the highest level, and with this analysis, it allows microinjection of this sperm without any damage to the live sperm cell.
Living sperm cells are enlarged 400×2 times at most in standard microinjection applications. At this magnification, the general morphological features of the sperm (head structure, neck structure and tail structure) can be examined. However, organelles that are found in head structure of sperm cell, and structures that should not be present such as vacuoles and the cell nucleus cannot be examined.
Special microscopes equipped with advanced technology are used for this application. In the procedure performed using the IMSI technique, the intracellular structures and cell nucleus morphology of living sperm are examined in detail using 6000-8000 times magnification. In this way, 25% to 40% higher fertilization rate can be achieved with the microinjection procedure performed after detailed selection of normal or closest to normal sperm. This technique is first performed in the Brussels IVF center in our country.
Genetic and environmental factors cause DNA damage of varying degrees and severity in male semen. Sperm containing damaged DNA is more likely to be used in the ICSI technique generally used in IVF treatment. IMSI (Intracytoplasmic Morphologically Selected Sperm Injection) is the best technique to show whether there is DNA damage in live sperm.
In researches conducted by Garolla in 2008, the finding of a direct relationship between sperm DNA damage and the formation of vacuoles in the sperm head opened the doors of the technique. In the classical ICSI, "good sperm" was selected since sperm with normal morphology and motility were selected. But in the selection of sperm in this way, it is not known whether sperm DNA is good or not. Since the IMSI technique is used instead of ICSI, sperm with less DNA damage can be selected. Compared to ICSI performed in normal in vitro fertilization, where sperms are selected by magnifying 400×2 times, they are selected by magnifying 6000-8000 times in the IMSI technique, and thus it is thought that sperm with better DNA are selected by this way.
High DNA damage in eggs and sperm can cause inability to obtain good quality embryos, low pregnancy and implantation rates, and miscarriages.
Abnormal cell metabolism and oxidative stress make it difficult to maintain the integrity of sperm DNA chains, and cause various damages in DNA strands. It has been observed that conditions such as advanced age, smoking, air pollution, long sexual abstinence, and exposure of the testicles to an abnormally hot environment increase the damage to sperm DNA in men. If the sperm DNA damage is less than 8%, the DNA of the eggs can repair the damaged DNA of the sperm and a healthy child can be born. However, studies have shown that anomalies, in other words abnormal growth, premature aging, lung and skin tumors can also develop in embryos and mice born when the DNA repair is incomplete. Thus, the well-being of the DNA structure in the sperm is very important in terms of ensuring a healthier transmission of genetic information to future progeny.
As the DNA damage in the sperm increases when the man's age exceeds 35, the rate of miscarriage increases.
However, according to the results of neurological examinations performed with the children born with ICSI at the age of 8, no difference was detected between the normally born children and those born with ICSI, but major congenital anomalies were slightly higher in ICSI children. Equal comprehension, cognition, and motor development were found in 10-year-old children born in both ways.
Considering our knowledge, it is unknown what will happen after many years to children resulting from ICSI performed today using sperm with damaged DNA. Natural selection of the sperm was bypassed after the beginning of the use of ICSI in the treatment of infertility in 1992. With ICSI, embryos can be obtained from sperms with damaged DNA that cannot fertilize in natural way. In embryos developing from eggs fertilized by sperm with damaged DNA, promutation and mutation may develop causing infertility and child cancers in future children. In humans, when there is a vacuole in the sperm, that is, when there is DNA damage, there is no evidence of what kind of damage this may cause in the children born in later years, but it can be said that there may be less risk in children born when sperms with good DNA structure are selected with IMSI.
For whom should IMSI be used?
Should IMSI be used in all patients or only in patients over 35 years of age or in the patients in oligoasthenoteratozoospermia, azoospermia subgroup?
What should we do in these patients when 100% damaged sperm are found in IMSI? I think we need to find new classification systems in sperm for this. In conclusion, children to be born with the right sperm selection made with IMSI before ICSI will be healthier. However, choosing IMSI instead of ICSI without knowing the risks that may occur in children born from ICSI after many years gives the result that it should be done in all patients.