Sperm Processing for IVF

The birth of Louise Brown, the fi rst human who was born on 25 July 1978 after the application of assisted reproduction techniques hallmarks the advent of the era of assisted reproductive technology (ART) in the human [ 1 ]. The fi rst in vitro fertilization (IVF) cases, including that of Louise Brown, were performed to treat female tubal infertility. Subsequently, the demand for assisted reproduction techniques grew dramatically with the increasing number of men showing poor semen quality. Hence, scientists and clinicians were prompted to develop a wide array of different laboratory techniques focusing on the selection and enrichment of motile and functionally competent spermatozoa from the ejaculate. Since our understanding of the fertilization process and various sperm functions also extended signifi cantly and the percentage of andrological cases with even poorer semen quality increased rapidly, the initial simple sperm separation techniques were not suffi cient enough anymore, and new improved sperm separation techniques had to be developed. Spermatozoa are not only the smallest but also the most polarized cell in the body (sperm head and a fl agellum) that even fulfi ll their physiological functions, fertilization of oocytes, outside the body in a different individual, the female genital tract. Thus, the male germ cell is a very specialized and in certain aspects very sensitive cell. The latter is based on the sperm cell’s special composition of its plasma membrane with an extraordinary high amount of poly-unsaturated fatty acids, particularly docosahexanoic acid with six double bonds in the molecule [ 2 ]. This feature is the foundation of the high membrane fl uidity which is essential in maintaining the extreme polarization of the sperm and is required for normal sperm function [ 3 ]. Together with the sperm cell’s lack of intrinsic reactive oxygen Chapter 2 Sperm Processing for IVF