+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Sperm selection in natural conception: what can we learn from Mother Nature to improve assisted reproduction outcomes?


      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.



          In natural conception only a few sperm cells reach the ampulla or the site of fertilization. This population is a selected group of cells since only motile cells can pass through cervical mucus and gain initial entry into the female reproductive tract. In animals, some studies indicate that the sperm selected by the reproductive tract and recovered from the uterus and the oviducts have higher fertilization rates but this is not a universal finding. Some species show less discrimination in sperm selection and abnormal sperm do arrive at the oviduct. In contrast, assisted reproductive technologies (ART) utilize a more random sperm population. In this review we contrast the journey of the spermatozoon in vivo and in vitro and discuss this in the context of developing new sperm preparation and selection techniques for ART.


          A review of the literature examining characteristics of the spermatozoa selected in vivo is compared with recent developments in in vitro selection and preparation methods. Contrasts and similarities are presented.


          New technologies are being developed to aid in the diagnosis, preparation and selection of spermatozoa in ART. To date progress has been frustrating and these methods have provided variable benefits in improving outcomes after ART. It is more likely that examining the mechanisms enforced by nature will provide valuable information in regard to sperm selection and preparation techniques in vitro. Identifying the properties of those spermatozoa which do reach the oviduct will also be important for the development of more effective tests of semen quality. In this review we examine the value of sperm selection to see how much guidance for ART can be gleaned from the natural selection processes in vivo.

          Related collections

          Most cited references183

          • Record: found
          • Abstract: found
          • Article: not found

          Sperm DNA integrity assessment in prediction of assisted reproduction technology outcome.

          The sperm chromatin structure assay (SCSA) has been suggested as a predictor of fertility in vivo as well as in vitro. The available data however, have been based on limited numbers of treatments. We aimed to define the clinical role of SCSA in assisted reproduction. A total of 998 cycles [387 intrauterine insemination (IUI), 388 IVF and 223 ICSI] from 637 couples were included. SCSA results were expressed as DNA fragmentation index (DFI) and high DNA stainable (HDS) cell fractions. Outcome parameters were biochemical pregnancy (BP), clinical pregnancy (CP) and delivery (D). For IUI, the odds ratios (ORs) for BP, CP and D were significantly lower for couples with DFI >30% as compared with those with DFI 30% group, the results of ICSI were significantly better than those of IVF. DFI can be used as an independent predictor of fertility in couples undergoing IUI. As a result, we propose that all infertile men should be tested with SCSA as a supplement to the standard semen analysis. When DFI exceeds 30%, ICSI should be the method of choice.
            • Record: found
            • Abstract: found
            • Article: not found

            Genome-wide single-cell analysis of recombination activity and de novo mutation rates in human sperm.

            Meiotic recombination and de novo mutation are the two main contributions toward gamete genome diversity, and many questions remain about how an individual human's genome is edited by these two processes. Here, we describe a high-throughput method for single-cell whole-genome analysis that was used to measure the genomic diversity in one individual's gamete genomes. A microfluidic system was used for highly parallel sample processing and to minimize nonspecific amplification. High-density genotyping results from 91 single cells were used to create a personal recombination map, which was consistent with population-wide data at low resolution but revealed significant differences from pedigree data at higher resolution. We used the data to test for meiotic drive and found evidence for gene conversion. High-throughput sequencing on 31 single cells was used to measure the frequency of large-scale genome instability, and deeper sequencing of eight single cells revealed de novo mutation rates with distinct characteristics. Copyright © 2012 Elsevier Inc. All rights reserved.
              • Record: found
              • Abstract: found
              • Article: not found

              Sperm DNA fragmentation: mechanisms of origin, impact on reproductive outcome, and analysis.

              To review the mechanisms responsible for DNA fragmentation in human sperm, including those occurring during spermatogenesis and transport through the reproductive tract. The mechanisms examined include: apoptosis in the seminiferous tubule epithelium, defects in chromatin remodeling during the process of spermiogenesis, oxygen radical-induced DNA damage during sperm migration from the seminiferous tubules to the epididymis, the activation of sperm caspases and endonucleases, damage induced by chemotherapy and radiotherapy, and the effect of environmental toxicants. The different tests currently used for sperm DNA fragmentation analysis and the factors that determine the predictive value of sperm DNA fragmentation testing and their implications in the diagnosis and treatment of infertility are also discussed. Finally, we also scrutinize how the presence in the embryonic genome of DNA strand breaks or modifications of DNA nucleotides inherited from the paternal genome could impact the embryo and offspring. In particular we discuss how abnormal sperm could be dealt with by the oocyte and how sperm DNA abnormalities, which have not been satisfactorily repaired by the oocyte after fertilization, may interfere with normal embryo and fetal development. Sperm DNA can be modified through various mechanisms. The integrity of the paternal genome is therefore of paramount importance in the initiation and maintenance of a viable pregnancy both in a natural conception and in assisted reproduction. The need to diagnose sperm at a nuclear level is an area that needs further understanding so that we can improve treatment of the infertile couple. Copyright 2010 American Society for Reproductive Medicine. Published by Elsevier Inc. All rights reserved.

                Author and article information

                Hum Reprod Update
                Hum. Reprod. Update
                Human Reproduction Update
                Oxford University Press
                November 2015
                19 September 2015
                19 September 2015
                : 21
                : 6
                : 711-726
                [1 ]Boston IVF , 130 Second Ave, Waltham, MA 02451, USA
                [2 ]Reproductive and Developmental Biology, Medical School, Ninewells Hospital, University of Dundee , Dundee DD19SY, UK
                [3 ]IVI Valencia , Guadassuar 1 Bajo, 46015 Valencia, Spain
                Author notes
                [* ]Correspondence address. E-mail: dsakkas@ 123456bostonivf.com
                © The Author 2015. Published by Oxford University Press on behalf of the European Society of Human Reproduction and Embryology.

                This is an Open Access article distributed under the terms of the Creative Commons Attribution License ( http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

                : 14 November 2014
                : 15 June 2015
                : 12 August 2015
                Funded by: TENOVUS (Scotland), University of Dundee, Medical Research Council (MRC grant numbers 4190 and 12492) and NHS Scotland
                Custom metadata
                November/December 2015

                Human biology
                fallopian tube,spermatozoa,uterine tube,uterus,vagina,sperm selection
                Human biology
                fallopian tube, spermatozoa, uterine tube, uterus, vagina, sperm selection


                Comment on this article