title: Increased sperm mitochondrial DNA content in male infertility.
abstract: BACKGROUND
  There is increasing evidence that mitochondrial DNA (mtDNA) anomalies in sperm may lead to infertility. Point mutations, deletions and the presence of a specific mtDNA haplogroup have been associated with poor sperm quality, but little attention has been paid to the role of mtDNA content.
  
  
  METHODS
  Using density gradient separation and swim-up methods, we selected motile sperm from 32 normal and 35 abnormal sperm samples. The mtDNA/beta-globin gene ratio was determined by real-time quantitative PCR.
  
  
  RESULTS
  The average mtDNA/beta-globin ratio of sperm collected from 100% density layers was 1.4 for normal sperm, 6.1 for sperm samples presenting at least one abnormal criterion [among the three criteria established by World Health Organization (1999), i.e. sperm count, motility and morphology], and 9.1 for sperm samples presenting two or more of these abnormal criteria. These differences are very highly significant (P < 0.0001). The mtDNA numbers were also much greater in sperm collected from the 40% density gradient layers (mean: 17.1, P < 0.001), known to contain the most abnormal sperm of the sperm samples, than in those collected from the 100% layers known to contain sperm with the best fertilizing ability.
  
  
  CONCLUSIONS
  Our results showed significant mtDNA amplification in sperm collected from abnormal sperm samples.
authors.affiliation: INSERM EMI-U 00-18, Laboratoire de Biochimie et Biologie Moléculaire, Laboratoire d'Histologie-Embryologie-Cytologie, UF de Biologie de la Reproduction, CHU d'Angers, F-49033 Angers, France.
authors.forename: P
authors.initials: P
authors.lastname: May-Panloup
authors.forename: M-F
authors.initials: MF
authors.lastname: Chrétien
authors.forename: F
authors.initials: F
authors.lastname: Savagner
authors.forename: C
authors.initials: C
authors.lastname: Vasseur
authors.forename: M
authors.initials: M
authors.lastname: Jean
authors.forename: Y
authors.initials: Y
authors.lastname: Malthièry
authors.forename: P
authors.initials: P
authors.lastname: Reynier
mesh_terms: D003199:Computer Systems; D004272:DNA, Mitochondrial / Q000378:metabolism* / Q000502:physiology; D005914:Globins / Q000378:metabolism; D006801:Humans; D007248:Infertility, Male / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D008297:Male; D016133:Polymerase Chain Reaction; D013076:Sperm Count; D013081:Sperm Motility; D013094:Spermatozoa / Q000002:abnormalities / Q000166:cytology / Q000378:metabolism*
chemical_list: D004272:DNA, Mitochondrial; D005914:Globins