title: A single-cell assay for telomere DNA content shows increasing telomere length heterogeneity, as well as increasing mean telomere length in human spermatozoa with advancing age.
abstract: OBJECTIVE
  The effect of age on telomere length heterogeneity in men has not been studied previously. Our aims were to determine the relationship between variation in sperm telomere length (STL), men's age, and semen parameters in spermatozoa from men undergoing in vitro fertilization (IVF) treatment.
  
  
  METHODS
  To perform this prospective cross-sectional pilot study, telomere length was estimated in 200 individual spermatozoa from men undergoing IVF treatment at the NYU Fertility Center. A novel single-cell telomere content assay (SCT-pqPCR) measured telomere length in individual spermatozoa.
  
  
  RESULTS
  Telomere length among individual spermatozoa within an ejaculate varies markedly and increases with age. Older men not only have longer STL but also have more variable STL compared to younger men. STL from samples with normal semen parameters was significantly longer than that from samples with abnormal parameters, but STL did not differ between spermatozoa with normal versus abnormal morphology.
  
  
  CONCLUSIONS
  The marked increase in STL heterogeneity as men age is consistent with a role for ALT during spermatogenesis. No data have yet reported the effect of age on STL heterogeneity. Based on these results, future studies should expand this modest sample size to search for molecular evidence of ALT in human testes during spermatogenesis.
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.|Graduation Program in Pathology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil, 24033.
authors.forename: Danielle M F
authors.initials: DM
authors.lastname: Antunes
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.
authors.forename: Keri H
authors.initials: KH
authors.lastname: Kalmbach
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.
authors.forename: Fang
authors.initials: F
authors.lastname: Wang
authors.affiliation: Department of Psychiatry, New York University School of Medicine, New York, NY, 10016, USA.
authors.forename: Roberta C
authors.initials: RC
authors.lastname: Dracxler
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.
authors.forename: Michelle L
authors.initials: ML
authors.lastname: Seth-Smith
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.
authors.forename: Yael
authors.initials: Y
authors.lastname: Kramer
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA.
authors.forename: Julia
authors.initials: J
authors.lastname: Buldo-Licciardi
authors.affiliation: Graduation Program in Pathology, Fluminense Federal University, Niteroi, Rio de Janeiro, Brazil, 24033.
authors.forename: Fabiana B
authors.initials: FB
authors.lastname: Kohlrausch
authors.affiliation: Department of Obstetrics and Gynecology, New York University, Langone Medical Center, New York, NY, 10016, USA. david.keefe@nyumc.org.|Department of Obstetrics and Gynecology, NYU School of Medicine, Laboratory of Reproductive Medicine, 180 Varick Street, New York, NY, 10014, USA. david.keefe@nyumc.org.
authors.forename: David L
authors.initials: DL
authors.lastname: Keefe
mesh_terms: D000328:Adult; D003430:Cross-Sectional Studies; D004247:DNA / Q000032:analysis*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010331:Paternal Age; D011446:Prospective Studies; D059010:Single-Cell Analysis / Q000379:methods*; D013094:Spermatozoa / Q000502:physiology*; D016615:Telomere / Q000235:genetics*; D059505:Telomere Homeostasis / Q000235:genetics
chemical_list: D004247:DNA
keywords: Human spermatozoa; In vitro fertilization; Paternal age; Sperm morphology; Telomeres