[Frontiers in Bioscience 12,105-114, January 1, 2007]

Treatment of severe male infertility by micromanipulation-assisted fertilization: an update

Jan Tesarik 1 and Carmen Mendoza 1,2

1 MAR and Gen, Molecular Assisted Reproduction and Genetics, 2 Department of Biochemistry and Molecular Biology, University of Granada Faculty of Sciences, Campus Universitario Fuentenueva, 70018 Granada, Spain

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. New developments in micromanipulation-assisted fertilization techniques and their use in male infertility management
3.1. New technical support
3.1.1. Laser-assisted ICSI
3.1.2. The use of Polscope system for meiotic spindle visualization in living oocytes
3.1.3. The use of high-magnification sperm selection
3.1.4. In vitro culture systems for germ cell in vitro maturation
4. New developments in the diagnosis and treatment of genetic and epigenetic deficiencies of the male gamete
4.1. Sperm chromatin defects and DNA fragmentation
4.2. Deficiency of oocyte-activating factors
4.3. Deficiency of the sperm centriole
5. Clinical efficacy
5.1. Management of severe teratozoospermia
5.2. Management of high degree of sperm DNA fragmentation
5.3. Management of maturation arrest
6. Health hazards for the offspring
7. References

1. ABSTRACT

In the past 5-10 years the evolution of micromanipulation-assisted fertilization for the treatment of severe male infertility was marked by the introduction of new technical support, refinement of diagnostic methods for the evaluation of sperm developmental potential, and development of new treatment regimens for the newly discovered abnormalities. The new technical support involves the use of non-contact laser technology to assist micromanipulation for fertilization, the evolution of polarized microscopy-based optical systems to non-invasively detect the position of the meiotic spindle in living human oocytes, and the development of high-magnification optical systems for a better morphological selection of spermatozoa to be used for fertilization. Diagnostic approaches were enriched by commercial availability of kits for the analysis of sperm DNA integrity, leading to the definition of sperm nuclear DNA damage as a distinct cause of male infertility, and by the development of tests, based on heterologous ICSI, for detection of sperm failure to activate oocytes. Several treatment options for these conditions have been proposed and are currently being tested in larger-scale trials. Some technical improvement was also achieved in the field of in vitro maturation of germ cells from men with in vivo maturation arrest, but only a modest clinical improvement resulted from their application. As to the risk for the offspring, recent data are rather reassuring. Except for the risk of transmission of genetically based infertility, no straightforward evidence for a health risk derived from these techniques has been provided. Nevertheless, caution is necessary, particularly concerning the eventual increase in genomic-imprinting abnormalities.