Research Article Clinical and Structural Features of Sperm Head Vacuoles in Men Included in the In Vitro Fertilization Programme Nina Fekonja, 1 Jasna Štrus, 1 Magda Tušek CnidariI, 1,2 Katja Knez, 2 Eda Vrtacnik Bokal, 3 Ivan Verdenik, 3 and Irma Virant-Klun 3 1 Department of Biology, Biotechnical Faculty, University of Ljubljana, Vecna pot 111, SI-1000 Ljubljana, Slovenia 2 National Institute of Biology, Vecna pot 111, SI-1000 Ljubljana, Slovenia 3 Reproductive Unit, Department of Obstetrics and Gynecology, University Medical Centre Ljubljana, Slajmerjeva 3, SI-1000 Ljubljana, Slovenia Correspondence should be addressed to Irma Virant-Klun; irma.virant@kclj.si Received 10 January 2014; Revised 8 March 2014; Accepted 17 March 2014; Published 9 April 2014 Academic Editor: Raymond J. Rodgers Copyright © 2014 Nina Fekonja et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te human sperm head vacuoles and their role in male infertility are still poorly understood. Te aim of this study was to identify the clinical and ultrastructural features of human sperm head vacuoles in men included in the in vitro fertilization programme: men with normal (normozoospermia) and impaired sperm morphology (teratozoospermia). Te sperm samples were observed under 6000-time magnifcation using motile sperm organelle morphology examination (MSOME). Te proportion of sperm with head vacuoles was evaluated and related to the outcome of in vitro fertilization. Te sperm of men with impaired sperm morphology was characterized by a higher proportion of sperm head vacuoles. Te sperm head vacuoles were related to impaired semen quality (sperm concentration, motility, and morphology) but were not infuenced by male factors (semen volume, height, age, weight, or body mass index). Moreover, sperm head vacuoles were related to impaired fertilization rate merely afer classical in vitro fertilization (IVF), while there was no relation to pregnancy. In a subgroup of men, the sperm was fxed and observed by transmission electron microscopy (TEM). Te ultrastructural study revealed that sperm head vacuoles are large nuclear indentations of various sizes and positions, packed with membranous material organized in membrane whorls (MW). 1. Introduction Male infertility can be related to abnormal morphology of spermatozoa. In the last years, there has been much debate on a new potential parameter of sperm quality and male fertility, sperm head vacuoles. In spite of that, the human sperm head vacuoles and their potential role in male infertility are still poorly understood. Using motile sperm organelle morphology examination (MSOME), where living sperm cells are visualized with DIC Nomarski microscopy at magnifcation of 6000 times, some fne morphological structures are visible which might be useful to determine the quality of sperm. Tis method shows small and larger surface concavities termed sperm vacuoles, usually located in the head of sperm cells. Te nature and origin of sperm head vacuoles are still uncertain and it is not clear whether they originate from the nucleus or acrosome or other membranous structures. Vacuoles are also found in almost all samples with normal sperm morphology (>14% morphologically normal spermatozoa according to Kruger’s strict criteria) and are mainly located at the tip or middle area of sperm heads [1]. Te three-dimensional deconvolution images, which detect DNA, showed vacuoles as “nuclear concavities” and atomic force microscopy revealed intact but slightly sunken plasma membrane in the area of vacuoles [2]. Moreover, the electron microscope images of sperm samples in patients with abnormal sperm morphology, teratozoosper- mia (<14% normal spermatozoa in the sample according to Kruger’s strict criteria), showed vacuoles exclusively in the area of sperm nucleus [3]. Te anterior location of sperm head vacuoles led to the question about their possible origin from acrosome. Te induction of acrosome reaction by Hindawi Publishing Corporation BioMed Research International Volume 2014, Article ID 927841, 12 pages http://dx.doi.org/10.1155/2014/927841