Certain factors in sperm, that have a negative effect on the embryonic development, are mostly resulting of reduced sperm maturity.
Among others DNA-fragmentations are included.
All approaches to diagnose were invasive up until now, which made the further usage of sperm cells impossible.
IMSI
The Intracytoplasmic Morphologically Selected Sperm Injection permits a screening of the sperm cells at a very high magnification rate without colouration in real time.
Numerous publications showed that a pre-selection of the spermatozoa is essential in order for the ICSI to be successful.
Performing an ICSI with sperm cells that have been selected at high magnification, leads to higher pregnancy rates, especially in cases, in which the degree of DNA-fragmentation in sperm has been very high.
IMSI and PICSI deliver an improvement of results in some cases:
· if there is no fertilization after ICSI,
· if the implantation did not work,
· if a Teratozoospermie is existent,
· if the DNA-fragmentation is high, and also possibly
· if idiopathic infertility is existent;
GENERAL INFORMATION ABOUT IMSI
Paternal factors, which can have a negative effect on the development (DNA):
- Cytoplasma-Retention
- Persistent Histone
- meiotic defects – chromosomal aberrationen
- Apoptotic procedures
- DNA-Fragmentation
In the majority of cases the reason is a reduced sperm maturity
Sperm- Diagnosis
World Health Organization
- Routine Semen Analysis
- Serial semen samples (at least two)
Kruger´s strict criteria
Optional Tests
- Hypo-Osmotic Swelling (HOS) Test
- Semen-culture
- CASA
- Sperm Penetration Assay (Hamster-Test)
- Hemi-Zona Binding Assay
- Acrosome Reaction Assay
- Y-Chromosome Microdeletion
- Sperm Chromatin (SCSA/TUNEL/Comet Assay)
- Kreatinine Kinase Assay
Current situation during ICSI
Selection of a motile spermatozoa at a magnification x400
What we do not know:
Is this the morphologically and functionally best sperm?
Are there new ways and tests to select sperm cells, that can be used for ICSI?
- Functional criteria
- Morphological criteria
Morphological test:
Intracytoplasmic
Morphologically Selected
Sperm
Injection (IMSI)
X 400
Is a morphological selection important?
IMSI
- Bartoov established a system for a selection at high magnification
- Uncoloured, real-time analysis of organelles from motile sperm cells at high-resolution
Bartoov et al., NEJM 2001
Bartoov et al., J. Androl. 2002
Bartoov et al., Fertil. Steril. 2003
Results
ICSI with abnormal spermatozoas:
- production of the pregnancy rate:
20,2% versus 36,7%
- reduction of the implantation rate:
9,6% versus 18,7%
The pre-selection of the spermatozoa is essential for a successful ICSI
De Vos et al., Hum. Reprod. 2003
Normal and abnormal Sperm cells
- Non-invasive presentation of the spindle using computer-assisted polarisation microscopy
- Presentation of the 3 layers of the Zona pellucida
Metaphase II - Egg cells
- The spindle plays an important role in the meiotic maturity of the human egg cell; it is responsible for the accurate alignment and distribution of chromosomes during cell division
- In 15-20% of all Metaphase II-egg cells, the spindle is not present
- The presence of the spindle is – beside the 1. Polkörperchen – an accurate indication of the maturity of the egg cell
- As the age of a woman increases, spindle-abnormalities are showing in egg cells
- The absence of the spindle is directly linked to a reduced fertilization rate and bad or no embryonic development
- The alignment of the spindle during ICSI also has an influence on the further development of the embryos.
The 3 layers of the Zona pellucida
- The Zona pellucida (ZP) consists of 3 layers of glykoproteins and surrounds the egg cell or embryo
- Using polarisationmicroscopy, the ZP can be judged in respect of the thickness of all 3 layers; with this data, the quality of the ZP of egg cells or embryos can be estimated in a better way
- Especially the inner layer of the ZP seems to set an important non-invasive mark for the potential development of the egg cell
- In patients over 35 years of age, the inner layer of the ZP appears thicker and the Glykoproteins of the ZP do not seem to be so well-organized
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