title: Strategies for fertility preservation and restoration in the male.
abstract: BACKGROUND
  Patients faced with infertility due to spermatogonial stem cell loss have currently semen cryobanking as only option for fertility preservation. A growing group of patients cannot benefit from this strategy as they are devoid of spermatozoa or even of any spermatogenic cell at the time of diagnosis. We therefore aimed at investigating alternative strategies to preserve or restore fertility.
  
  
  METHODS
  As fertility preservation strategies, we investigated the reintroduction of spermatogonial stem cells by spermatogonial stem cell transplantation (SCCT) or grafting of testicular tissue pieces. To restore fertility, we explored the germ cell differentiation capacity of human embryonic stem cells (hESC). Moreover, to avoid embryo destruction during hESC derivation, we aimed to derive hESC from single blastomeres of human embryos Results: For the SSCT, we showed that selection protocols based on magnetic and fluorescent cell sorting or selective-- matrix adhesion result in high germ cell-enriched fractions for transplantation. However, they are not sufficiently efficient to attain a pure germ cell fraction. After xenografting of human testicular testis tissue to immunodeficient mice, we observed long-term survival of spermatogonia within the grafts. In the fertility restoration part, we demonstrated the inductive capacity of sertoli cell-conditioned medium on germ cell differentiation from hESC. Finally, we derived two hESC from single blastomeres of two distinct four-cell stage human embryos.
  
  
  CONCLUSIONS
  The fertility preservation strategies that we investigated are currently on the edge of a clinical application. In the fertility restoration path, however, more extended research will be necessary.
authors.affiliation: Research Group Biology of the testis (BITE), Research Group Reproduction and Genetics (REGE), Research Department Embryology and Genetics, Vrije Universiteit Brussel, Laarbeeklaan 101, 1090 Jette, Belgium.
authors.forename: M
authors.initials: M
authors.lastname: Geens
keywords: (xeno)grafting; Spermatogonial stem cell; cancer; differentiation; fertility; hESC; transplantation
references.citation: Hum Reprod. 2003 Sep;18(9):1874-80
references.pmid: 12923142
references.citation: Nature. 2006 Jan 12;439(7073):216-9
references.pmid: 16227970
references.citation: Hum Reprod. 2007 May;22(5):1384-95
references.pmid: 17259225
references.citation: Hum Reprod Update. 2008 Mar-Apr;14(2):121-30
references.pmid: 18187526
references.citation: J Androl. 2002 Jul-Aug;23(4):537-45
references.pmid: 12065461
references.citation: Stem Cells. 2007 Sep;25(9):2330-8
references.pmid: 17585169
references.citation: Hum Reprod. 2006 Feb;21(2):390-6
references.pmid: 16311289
references.citation: Fertil Steril. 2008 Nov;90(5):2019-22
references.pmid: 18439593
references.citation: Cancer Res. 2001 Jan 15;61(2):706-10
references.pmid: 11212272
references.citation: JAMA. 2009 Nov 18;302(19):2127-34
references.pmid: 19920237
references.citation: Proc Natl Acad Sci U S A. 1994 Nov 22;91(24):11303-7
references.pmid: 7972054
references.citation: Proc Natl Acad Sci U S A. 1994 Nov 22;91(24):11298-302
references.pmid: 7972053
references.citation: Hum Reprod. 2003 Dec;18(12):2660-7
references.pmid: 14645188
references.citation: Fertil Steril. 2001 Feb;75(2):269-74
references.pmid: 11172826
references.citation: Hum Reprod. 2009 Nov;24(11):2709-17
references.pmid: 19633307
references.citation: Stem Cells. 2006 Aug;24(8):1931-6
references.pmid: 16644921
references.citation: Biol Reprod. 2002 Jan;66(1):21-8
references.pmid: 11751259
references.citation: Stem Cells. 2009 Jan;27(1):68-77
references.pmid: 18845765
references.citation: Cell Stem Cell. 2008 Feb 7;2(2):113-7
references.pmid: 18371431
references.citation: Fertil Steril. 2011 Feb;95(2):787-91
references.pmid: 21055744
references.citation: Nature. 2002 Aug 15;418(6899):778-81
references.pmid: 12181567
references.citation: Nature. 2004 Jan 8;427(6970):148-54
references.pmid: 14668819
references.citation: Nat Protoc. 2007;2(8):1963-72
references.pmid: 17703208
references.citation: Hum Reprod. 2009 Dec;24(12):2988-96
references.pmid: 19773223
references.citation: Hum Reprod. 2007 Jun;22(6):1603-11
references.pmid: 17483089
references.citation: Dev Cell. 2006 Jul;11(1):125-32
references.pmid: 16824959
references.citation: Cancer. 1986 Mar 1;57(5):1038-41
references.pmid: 3455840
references.citation: Hum Reprod. 2011 Feb;26(2):282-93
references.pmid: 21123192
references.citation: Hum Reprod. 2007 Mar;22(3):733-42
references.pmid: 17082221
references.citation: Fertil Steril. 2008 Oct;90(4 Suppl):1411-6
references.pmid: 18023438
references.citation: Fertil Steril. 2009 May;91(5 Suppl):2264-72
references.pmid: 18394623
references.citation: J Assist Reprod Genet. 2011 May;28(5):471-80
references.pmid: 21318592
references.citation: Fertil Steril. 2010 Feb;93(3):986-94
references.pmid: 19064262
references.citation: Hum Reprod. 2009 Dec;24(12):3150-9
references.pmid: 19770126
references.citation: Science. 2003 May 23;300(5623):1251-6
references.pmid: 12730498
references.citation: Stem Cells. 2008 Dec;26(12):3075-85
references.pmid: 18802037
references.citation: Hum Reprod. 2008 Aug;23(8):1742-7
references.pmid: 18503052
references.citation: Mutat Res. 1993 Dec;290(2):193-200
references.pmid: 7694110
references.citation: Hum Reprod. 2006 Feb;21(2):484-91
references.pmid: 16210383
references.citation: Hum Mol Genet. 2004 Apr 1;13(7):727-39
references.pmid: 14962983
references.citation: Biol Reprod. 2004 Dec;71(6):2087-91
references.pmid: 15317690
references.citation: Mol Reprod Dev. 1999 Jun;53(2):142-8
references.pmid: 10331452
references.citation: J Cell Physiol. 2007 Apr;211(1):149-58
references.pmid: 17167785
references.citation: Hum Reprod. 2009 Sep;24(9):2255-63
references.pmid: 19525299
references.citation: Hum Reprod. 2008 Dec;23(12):2874
references.pmid: 18854403
references.citation: Reprod Biomed Online. 2007 Jun;14(6):718-23
references.pmid: 17579986