title: Role of compensatory meiosis mechanisms in human spermatogenesis.
abstract: Disturbances of checkpoints in distinct stages of spermatogenesis (mitosis, meiosis, and spermiogenesis) contribute to impaired spermatogenesis; however, the efficiency of meiotic entry has not been investigated in more detail. In this study, we analyzed azoospermic patients with defined spermatogenic defects by the use of octamer-binding protein 2 for type A spermatogonia, sarcoma antigen 1 for mitosis-meiosis transition and SMAD3 for pachytene spermatocytes. Especially patients with maturation arrest (MA) at the level of primary spermatocytes showed significantly reduced numbers of spermatogonia compared with patients with histologically intact spermatogenesis or patients with hypospermatogenesis (Hyp). For a detailed individual classification of the patients, we distinguished between 'high efficiency of meiotic entry' (high numbers of pachytene spermatocytes) and 'low efficiency of meiotic entry' (low numbers of pachytene spermatocytes). Only patients with histologically normal spermatogenesis (Nsp) and patients with Hyp showed normal numbers of spermatogonia and a high efficiency of meiotic entry. Of note, only patients with histologically Nsp or patients with Hyp could compensate low numbers of spermatogonia with a high efficiency of meiotic entry. In contrast, patients with MA always showed a low efficiency of meiotic entry. This is the first report on patients with impaired spermatogenesis, showing that half of the patients with Hyp but all patients with MA cannot compensate reduced numbers in spermatogonia with a highly efficient meiosis. Thus, we suggest that compensatory meiosis mechanisms in human spermatogenesis exist.
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany.
authors.forename: Mareike
authors.initials: M
authors.lastname: Borgers
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Wolter
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany.
authors.forename: Anna
authors.initials: A
authors.lastname: Hentrich
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Bergmann
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany.
authors.forename: Angelika
authors.initials: A
authors.lastname: Stammler
authors.affiliation: Department of Obstetrics and GynecologyMedical Faculty, Feulgenstraße 12, D-35392 Giessen, GermanyInstitute of Veterinary-Anatomy-Histology and -Embryology, Frankfurter Straße 98, D-35392 Giessen, Germany Lutz.Konrad@gyn.med.uni-giessen.de.
authors.forename: Lutz
authors.initials: L
authors.lastname: Konrad
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D015415:Biomarkers / Q000378:metabolism; D002453:Cell Cycle; D006801:Humans; D008297:Male; D008540:Meiosis / Q000502:physiology*; D008875:Middle Aged; D050813:Octamer Transcription Factor-2 / Q000378:metabolism; D009845:Oligospermia / Q000235:genetics* / Q000378:metabolism; D051900:Smad3 Protein / Q000378:metabolism; D013091:Spermatogenesis / Q000235:genetics*; D013093:Spermatogonia / Q000378:metabolism*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D050813:Octamer Transcription Factor-2; D051900:Smad3 Protein