title: Factors associated with aberrant imprint methylation and oligozoospermia.
abstract: Disturbingly, the number of patients with oligozoospermia (low sperm count) has been gradually increasing in industrialized countries. Epigenetic alterations are believed to be involved in this condition. Recent studies have clarified that intrinsic and extrinsic factors can induce epigenetic transgenerational phenotypes through apparent reprogramming of the male germ line. Here we examined DNA methylation levels of 22 human imprinted loci in a total of 221 purified sperm samples from infertile couples and found methylation alterations in 24.8% of the patients. Structural equation model suggested that the cause of imprint methylation errors in sperm might have been environmental factors. More specifically, aberrant methylation and a particular lifestyle (current smoking, excess consumption of carbonated drinks) were associated with severe oligozoospermia, while aging probably affected this pathology indirectly through the accumulation of PCB in the patients. Next we examined the pregnancy outcomes for patients when the sperm had abnormal imprint methylation. The live-birth rate decreased and the miscarriage rate increased with the methylation errors. Our research will be useful for the prevention of methylation errors in sperm from infertile men, and sperm with normal imprint methylation might increase the safety of assisted reproduction technology (ART) by reducing methylation-induced diseases of children conceived via ART.
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.|Laboratory of Animal Reproduction and Development, Graduate School of Agricultural Science, Tohoku University, 1-1 Amamiya-machi, Tsutsumidori, Aoba-ku, Sendai, 981-8555, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Kobayashi
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Miyauchi
authors.affiliation: Department of Development and Environmental Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
authors.forename: Nozomi
authors.initials: N
authors.lastname: Tatsuta
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Akane
authors.initials: A
authors.lastname: Kitamura
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Okae
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Hiura
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.|St. Luke Clinic, Oita, 870-0823, Japan.
authors.forename: Akiko
authors.initials: A
authors.lastname: Sato
authors.affiliation: St. Luke Clinic, Oita, 870-0823, Japan.
authors.forename: Takafumi
authors.initials: T
authors.lastname: Utsunomiya
authors.affiliation: Departments of Obstetrics and Gynecology, Tohoku University Graduate School of Medicine, Sendai, 980-8574, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Yaegashi
authors.affiliation: Department of Development and Environmental Medicine, Tohoku University Graduate School of Medicine, Sendai, 980-8575, Japan.
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Nakai
authors.affiliation: Department of Informative Genetics, Tohoku University Graduate School of Medicine, 2-1 Seiryo-cho, Aoba-ku, Sendai, 980-8575, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Arima
mesh_terms: D000328:Adult; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D018392:Genomic Imprinting; D006801:Humans; D008297:Male; D015999:Multivariate Analysis; D009845:Oligospermia / Q000235:genetics*; D011078:Polychlorinated Biphenyls / Q000378:metabolism; D011247:Pregnancy; D011256:Pregnancy Outcome; D027724:Reproductive Techniques, Assisted; D013094:Spermatozoa / Q000378:metabolism
chemical_list: D011078:Polychlorinated Biphenyls