| 1. |
- Bungum, Mona, et al.
(author)
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Sperm chromatin structure assay parameters measured after density gradient centrifugation are not predictive for the outcome of ART
- 2008
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In: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 23:1, s. 41374-41374
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Journal article (peer-reviewed)abstract
- BACKGROUND The sperm chromatin structure assay (SCSA) parameter DNA fragmentation index (DFI) has been shown to predict in vivo and in vitro fertility. So far most SCSA studies have been based on SCSA analysis performed on neat semen. The aim of this study is to assess whether SCSA analysis of sperm prepared by density gradient centrifugation (DGC) could add more information in regard to the prediction of treatment outcome. METHODS The study included 510 assisted reproductive technique (ART) cycles. SCSA was performed in neat semen and post DGC. SCSA results were expressed in terms of DFI and high DNA stainability (HDS) cell fractions. The outcome parameter was clinical pregnancy (CP). RESULTS Scatter-plot diagrams demonstrated that for DGC samples, no DFI cut-off values could be set for in vivo or in vitro fertility. In intrauterine insemination, IVF and ICSI groups the mean difference (95% CI) in DFI post DGC between those who achieved CP and those who did not was 0.2% (-1.7 to 2.0%), 0.4% (-1.9 to 2.8%) and 1.3% (-3.1 to 5.9%), respectively, none of these being statistically significant. The corresponding differences for HDS were 0.1% (-1.3 to 1.5%), 0.1% (-0.7 to 0.9%) and 0.6% (-1.6 to 2.7%), respectively (all P-values >0.6). CONCLUSIONS SCSA performed in semen prepared by DGC cannot predict the outcome of ART.
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| 2. |
- Consales, Claudia, et al.
(author)
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Exposure to persistent organic pollutants and sperm DNA methylation changes in Arctic and European populations.
- 2016
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In: Environmental and Molecular Mutagenesis. - : Wiley. - 1098-2280 .- 0893-6692. ; 57:3, s. 200-209
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Journal article (peer-reviewed)abstract
- Persistent organic pollutants (POPs), such as PCBs (polychlorinated biphenyls) and DDT [1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane], are environmental contaminants with potential endocrine disrupting activity. DNA methylation levels in peripheral blood lymphocytes have been associated with serum concentrations of POPs in Greenland Inuit and Korean populations. Greenland Inuits are characterized by the highest worldwide POP levels. In this cross-sectional study we evaluated the relationship between serum POP concentrations and DNA methylation levels in sperm of non-occupationally exposed fertile men from Greenland, Warsaw (Poland), and Kharkiv (Ukraine). Serum levels of PCB-153 [1,2,4-trichloro-5-(2,4,5-trichlorophenyl)benzene], as a proxy of the total PCBs body burden, and of p,p'-DDE [1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene], the main metabolite of DDT were measured. Sperm DNA methylation level was assessed globally by flow cytometric (FCM) immunodetection of 5-methyl-cytosines and at specific repetitive DNA sequences (Alu, LINE-1, Satα) by PCR-pyrosequencing after bisulfite conversion. Multivariate linear regression analysis was applied to investigate correlations between serum POP concentrations and DNA methylation. No consistent associations between exposure to POPs and sperm DNA methylation at repetitive DNA sequences were detected. A statistically significant global decrease in methylation was associated with exposure to either POP by FCM analysis. This is the first study to investigate environmental exposure to POPs and DNA methylation levels considering sperm as the target cells. Although POP exposure appears to have a limited negative impact on sperm DNA methylation levels in adult males, the global hypomethylation detected by one of the methods applied suggests that further investigation is warranted. Environ. Mol. Mutagen., 2015. © 2015 Wiley Periodicals, Inc.
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| 3. |
- Leter, Giorgio, et al.
(author)
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Exposure to Perfluoroalkyl Substances and Sperm DNA Global Methylation in Arctic and European Populations
- 2014
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In: Environmental and Molecular Mutagenesis. - : Wiley. - 1098-2280 .- 0893-6692. ; 55:7, s. 591-600
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Journal article (peer-reviewed)abstract
- Perfluoroalkyl substances (PFASs) are widely used in a variety of industrial processes and products, and have been detected globally in humans and wildlife. PFASs are suspected to interfere with endocrine signaling and to adversely affect human reproductive health. The aim of the present study was to investigate the associations between exposure to PFASs and sperm global methylation levels in a population of non-occupationally exposed fertile men. Measurements of PFASs in serum from 262 partners of pregnant women from Greenland, Poland and Ukraine, were also carried out by liquid chromatography tandem mass spectrometry. Perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), and perfluorononanoic acid (PFNA) were detected in 97% of the blood samples. Two surrogate markers were used to assess DNA global methylation levels in semen samples from the same men: (a) average DNA methylation level in repetitive DNA sequences (Alu, LINE-1, Sat alpha) quantified by PCR-pyrosequencing after bisulfite conversion; (b) flow cytometric immunodetection of 5-methyl-cytosines. After multivariate linear regression analysis, no major consistent associations between PFASs exposure and sperm DNA global methylation endpoints could be detected. However, since weak but statistically significant associations of different PFASs with DNA hypo- and hypermethylation were found in some of the studied populations, effects of PFASs on sperm epigenetic processes cannot be completely excluded, and this issue warrants further investigation. (C) 2014 Wiley Periodicals, Inc.
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