| 61. |
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| 62. |
- Spano, M, et al.
(författare)
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Exposure to PCB and p,p '-DDE in European and Inuit populations: impact on human sperm chromatin integrity
- 2005
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Ingår i: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 20:12, s. 3488-3499
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: Persistent organochlorine pollutants ( POP), such as polychlorinated biphenyls (PCB) and dichlorodiphenyldichloroethylene (p,p'-DDE), are widely found in the environment and considered potential endocrine-disrupting compounds (EDC). Their impact on male fertility is still unknown. METHODS: To explore the hypothesis that POP is associated with altered sperm chromatin integrity, a cross-sectional study involving 707 adult males ( 193 Inuits from Greenland, 178 Swedish fishermen, 141 men from Warsaw, Poland, and 195 men from Kharkiv, Ukraine) was carried out. Serum levels of 2,2', 4,4', 5,5'-hexachlorobiphenyl (CB-153), as a proxy of the total PCB burden, and of p,p'-DDE were determined. Sperm chromatin structure assay (SCSA) was used to assess sperm DNA/chromatin integrity. RESULTS: We found a strong and monotonically increasing DNA fragmentation index with increasing serum levels of CB-153 among European but not Inuit men, reaching a 60% higher average level in the highest exposure group. No significant associations were found between SCSA-derived parameters and p,p'-DDE serum concentrations. CONCLUSION: These results suggest that human dietary PCB exposure might have a negative impact on the sperm chromatin integrity of adult males but additional issues, including differences in the genetic background and lifestyle habits, still need to be elucidated.
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| 63. |
- Stronati, A., et al.
(författare)
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Relationships between sperm DNA fragmentation, sperm apoptotic markers and serum levels of CB-153 and p,p '-DDE in European and Inuit populations
- 2006
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Ingår i: Reproduction. - : Bioscientifica. - 1470-1626 .- 1741-7899. ; 132:6, s. 949-958
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Tidskriftsartikel (refereegranskat)abstract
- Persistent organochlorine pollutants (POPs) are suspected to interfere with hormone activity and the normal homeostasis of spermatogenesis. We investigated the relationships between sperm DNA fragmentation, apoptotic markers identified on ejaculated spermatozoa and POP levels in the blood of 652 adult males (200 Inuits from Greenland, 166 Swedish, 134 Polish and 152 Ukrainian). Serum levels of 2, 2', 4, 4', 5, 5'-hexachlorobiphenyl (CB-153), as a proxy of the total POP burden, and of 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE), as a proxy of the total DDT exposure were determined. Sperm DNA fragmentation was measured by using the TUNEL assay, whereas immunofluorescence methods were utilized for detecting proapoptotic (Fas) and anti-apoptotic (Bcl-xL) markers. Both TUNEL assay and apoptotic markers were statistically differed across the four populations. No correlation between neither sperm DNA fragmentation nor apoptotic sperm parameters and the large variations in POPs exposure was observed for the separate study groups. However, considering the European populations taken together, we showed that both %TUNEL positivity and Bcl-xL were related to CB-153 serum levels, whereas our study failed to demonstrate any relations between DDE and %TUNEL positivity and apoptotic sperm biomarkers (Fas and Bcl-xL) in any region or overall regions. These results suggest that CB-153 and related chemicals might alter sperm DNA integrity and Bcl-xL levels in European adult males, but not in the highly exposed Inuit men. Additional issues (genetic background, lifestyle habits and characterization of total xeno-hormonal activities) need to he investigated in order to fully assess the population variations observed.
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| 64. |
- Taylor, Kyla W., et al.
(författare)
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Evaluation of the Association between Persistent Organic Pollutants (POPs) and Diabetes in Epidemiological Studies: A National Toxicology Program Workshop Review
- 2013
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Ingår i: Environmental Health Perspectives. - : Environmental Health Perspectives. - 1552-9924 .- 0091-6765. ; 121:7, s. 774-783
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: Diabetes is a major threat to public health in the United States and worldwide. Understanding the role of environmental chemicals in the development or progression of diabetes is an emerging issue in environmental health. OBJECTIVE: We assessed the epidemiologic literature for evidence of associations between persistent organic pollutants (POPs) and type 2 diabetes. METHODS: Using a PubMed search and reference lists from relevant studies or review articles, we identified 72 epidemiological studies that investigated associations of persistent organic pollutants (POPs) with diabetes. We evaluated these studies for consistency, strengths and weaknesses of study design (including power and statistical methods), clinical diagnosis, exposure assessment, study population characteristics, and identification of data gaps and areas for future research. CONCLUSIONS: Heterogeneity of the studies precluded conducting a meta-analysis, but the overall evidence is sufficient for a positive association of some organochlorine POPs with type 2 diabetes. Collectively, these data are not sufficient to establish causality. Initial data mining revealed that the strongest positive correlation of diabetes with POPs occurred with organochlorine compounds, such as trans-nonachlor, dichlorodiphenyldichloroethylene (DDE), polychlorinated biphenyls (PCBs), and dioxins and dioxin-like chemicals. There is less indication of an association between other nonorganochlorine POPs, such as perfluoroalkyl acids and brominated compounds, and type 2 diabetes. Experimental data are needed to confirm the causality of these POPs, which will shed new light on the pathogenesis of diabetes. This new information should be considered by governmental bodies involved in the regulation of environmental contaminants.
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| 65. |
- Tiido, Tarmo, et al.
(författare)
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Exposure to persistent organochlorine pollutants associates with human sperm Y:X chromosome ratio.
- 2005
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Ingår i: Human Reproduction. - : Oxford University Press (OUP). - 0268-1161 .- 1460-2350. ; 20:7, s. 1903-1909
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: During the last decades, there has been concern that exposure to endocrine disruptors, such as persistent organochlorine pollutants (POPs), may contribute to sex ratio changes in offspring of exposed populations. METHODS: To investigate whether exposure to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) affect Y:X chromosome proportion, semen of 149 Swedish fishermen, aged 27–67 years, was investigated. The men provided semen and blood for analysis of hormone, CB-153 and p,p'-DDE levels. The proportion of Y- and X-chromosome bearing sperm in semen samples was determined by two-colour fluorescence in situ hybridization (FISH) analysis. RESULTS: Log transformed CB-153 as well as log transformed p,p'-DDE variables were both significantly positively associated with Y chromosome fractions (P-values=0.05 and <0.001, respectively). Neither age, smoking nor hormone levels showed any association with Y-chromosome fractions. CONCLUSIONS: This is the first study to indicate that exposure to POPs may increase the proportion of ejaculated Y-bearing spermatozoa. These data add to the growing body of evidence that exposure to POPs may alter the offspring sex ratio.
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| 66. |
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| 67. |
- Tiido, Tarmo, et al.
(författare)
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Modifying effect of the AR gene trinucleotide repeats and SNPs in the AHR and AHRR genes on the association between persistent organohalogen pollutant exposure and human sperm Y : X ratio
- 2007
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Ingår i: Molecular Human Reproduction. - : Oxford University Press (OUP). - 1460-2407. ; 13:4, s. 223-229
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Tidskriftsartikel (refereegranskat)abstract
- Persistent organohalogen pollutants (POPs) have been suggested to be involved in changing the proportion of ejaculated Y-bearing sperm. The androgen receptor (AR), aryl hydrocarbon receptor (AHR) and aryl hydrocarbon receptor repressor (AHRR) may modulate the effect of POPs with regard to previously observed sperm Y : X ratio changes. The objective of this study was to investigate whether sperm Y : X ratio changes in subjects exposed to 2,2'4,4'5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE) were modified by polymorphisms in the AR, AHR and AHRR genes. Semen for analysis of Y- and X-bearing sperm by two-colour fluorescence in situ hybridization and blood for leukocyte DNA genotyping and analysis of CB-153 and p,p'-DDE concentrations were obtained from 195 Swedish fishermen. The polymorphic CAG and GGN repeats in the AR and the R554K and P185A single-nucleotide polymorphisms in the AHR and AHRR genes, respectively, were determined by direct sequencing and allele-specific PCR. The effect of p,p'-DDE was modified by CAG or GGN repeat category in relation to the proportion of Y-bearing sperm (P = 0.005 and 0.02 for CAG and GGN, respectively). Moreover, p,p'-DDE, but not CB-153, levels were associated with Y-sperm proportion in men with CAG < 22 (P < 0.001), but not in those carrying CAG >= 22 (P = 0.73). This association was even more pronounced in subjects carrying a short CAG repeat in combination with an AHRR G-allele. The association in regard to p,p'-DDE was found for GGN = 23 but not for the GGN < 23 or GGN > 23 subgroups (P = 0.01, 0.44 and 0.99, respectively). In conclusion The endocrine-disrupting action of POPs, in relation to the observed changes in sperm Y : X ratio, may be modulated by the genes involved in sex steroid and dioxin-mediated pathways.
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| 68. |
- Toft, G, et al.
(författare)
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Quality control workshops in standardization of sperm concentration and motility assessment in multicentre studies
- 2005
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Ingår i: International Journal of Andrology. - : Wiley. - 0105-6263 .- 1365-2605. ; 28:3, s. 144-149
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Tidskriftsartikel (refereegranskat)abstract
- Semen quality has been reported to vary markedly between different regions. To properly assess the differences among countries a minimization of the variation among centres in the assessments of sperm quality is essential. We here report on the training and two subsequent follow-up workshops on assessments of sperm concentration and motility. A total of 26 fresh ejaculates were analysed by four persons who were collecting these data in a multicentre study on sperm quality. In addition, two trained technicians from one of the laboratories analysed the samples. At the first training workshop, the median coefficient of variation among centres in sperm concentration was 27.7%, but decreased markedly to 17.0% at the second workshop and 8.1% (P = 0.048) at the third workshop. The CV for evaluation of the proportion of progressive motile sperm decreased less and not statistically significant from 16.5 to 14.1% and 11.0% (P = 0.94). At the third workshop there were no statistical significant differences among centres in assessments of sperm concentration or motility (p > 0.57). Furthermore the coefficient of variation in assessments of sperm concentration and motility among centres were at the same level as between two trained technicians (p > 0.72). This study indicates that training and subsequent follow-up workshops can assure minimum variability among centres in assessments of sperm concentration and motility.
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| 69. |
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| 70. |
- Toft, Gunnar, et al.
(författare)
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Semen quality in relation to xenohormone and dioxin-like serum activity among inuits and three european populations
- 2007
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Ingår i: Environmental Health Perspectives. - : Environmental Health Perspectives. - 0091-6765 .- 1552-9924. ; 115:SUPPL1, s. 15-20
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Semen quality in humans may be influenced by exposure to endocrine-disrupting compounds. OBJECTIVES: We analyzed associations between semen characteristics and serum xenoestrogen receptor (XER), xenoandrogen receptor (XAR), and aryl hydrocarbon receptor (AhR) transactivity. XER and XAR activity were measured in serum samples cleared for endogenous steroid hormones and AhR activity in raw lipophilic serum extracts free of proteins. RESULTS: All together, 319 men from Warsaw (Poland), Greenland, Kharkiv (Ukraine), and Sweden provided semen and blood samples. No strong and consistent associations between xenobiotic activity and semen quality measures were observed in the four populations. However, when the data were combined across populations sperm concentration increased 40% per unit increase in XER activity [95% confidence interval (CI), 1-79%] in the subgroup with XER activity below the reference level. Among subjects with XER activity above the reference level an increase of 14% (95% CI, 2-28%) was found. Furthermore, an increase of 10% motile sperm per unit increase in XER activity below reference level (95% CI, 0.2-20) was found. We are unable to exclude that the associations are chance findings. CONCLUSION: Alteration of XER, XAR, or AhR transactivity within the range found in serum from the general European and Inuit population seems not to markedly deteriorate sperm cell concentration, motility, or morphology in adult men.
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