| 1. |
- Kvist, Linus, et al.
(författare)
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Exposure to persistent organic pollutants and sperm sex chromosome ratio in men from the Faroe Islands.
- 2014
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Ingår i: Environment International. - : Elsevier BV. - 1873-6750 .- 0160-4120. ; 73, s. 359-364
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Tidskriftsartikel (refereegranskat)abstract
- People in the Arctic as well as fishermen on the polluted Swedish east coast are highly exposed to persistent organic pollutants (POPs). These compounds have been shown to affect the sperm Y:X chromosome ratio. In present study, the aim was to investigate whether polychlorinated biphenyl (PCB) congeners and 1,1,-dichloro-2,2,-bis(p-chlorophenyl)ethane (p,p'-DDE) influence sperm sex chromosome ratio in Faroese men, and whether these men differ regarding Y:X ratio compared to Greenland Inuit and Swedish fishermen. The study population (n=449) consisted of young men from the general population (n=276) as well as proven fertile men (n=173). The Y:X ratio was assessed by fluorescent in situ hybridization. Serum concentrations of POPs were measured using gas chromatography. Associations between POP concentrations and Y:X ratio were calculated using linear and non-linear regression models as well as trend analysis and pairwise comparison of exposure data categorized into quartiles. The selected POPs were associated with Y:X ratio in fertile Faroese men, but not in the total population; p,p'-DDE (95% CI for B=-0.005 to -0.001, p=0.005) and ΣPCB (95% CI for B=-0.005 to -0.001, p=0.012). Since p,p'-DDE and ΣPCB correlated significantly (r=0.927, p<0.001), the results involving the exposure variables can be regarded as a single finding. The Y:X ratio for the total Faroese population was 0.500±0.018, which was statistically significantly lower than in both Inuit and Swedish fishermen (0.512 for both). In conclusion, Faroese men presented with lower Y:X ratio than Greenland Inuit and Swedish fishermen. Although no direct health effects are expected due to the lower Faroese Y:X ratio, it could be indicative of adverse effects on the reproductive system.
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| 2. |
- Kvist, Linus, et al.
(författare)
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Serum levels of perfluorinated compounds and sperm Y:X chromosome ratio in two European populations and in Inuit from Greenland.
- 2012
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Ingår i: Reproductive Toxicology. - : Elsevier BV. - 1873-1708 .- 0890-6238.
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Tidskriftsartikel (refereegranskat)abstract
- This study investigated whether perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS), which exhibit reproductive toxicity in experimental animals, affect sperm sex chromosome ratio. The Y:X ratio was determined by fluorescence in situ hybridization. Serum concentrations of PFOA and PFOS were measured in 607 men from Greenland, Poland and Ukraine using liquid chromatography-tandem mass spectrometry. Data was analyzed by linear and nonlinear regression. We observed no associations between PFOA and Y:X ratio (p=0.845 in a linear model, p=0.296 in a nonlinear model). A positive nonlinear association between PFOS and Y:X ratio was observed (p=0.016), with no association in a linear model (p=0.118). Analyzing the populations separately, a negative trend between categorized PFOS exposure and Y:X ratio was observed for the Inuit (B=-0.002, p=0.044). In conclusion, there was a negative trend between Y:X ratio and PFOS in the Inuit, while there was no association between PFOA and the Y:X ratio in adult men.
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| 3. |
- Kvist, Linus
(författare)
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Sperm Y:X chromosome ratio and androgen response in men exposed to environmental pollutants
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The last several decades have seen an increase in male infertility concomitant with a decline in the birth sex ratio. The conditions are believed to be linked to increased exposure to endocrine disrupting chemicals (EDCs), including the persistent organic pollutants or lifestyle factors e.g. smoking. The mechanism behind the lowered birth sex ratio is unknown, but might be due to an EDC-induced skewing of the proportions of Y to X chromosome bearing sperms. The aims of this thesis were: to elucidate possible associations between the sperm Y:X ratio and EDCs in several highly exposed populations, to evaluate any relationships that might exist between the Y:X ratio and sperm parameters in subfertile men, and to investigate the effect of smoking on androgen regulation in vivo as well as in vitro. The sperm sex chromosome ratio was investigated by fluorescent in situ hybridization (FISH) in n=449 men from the Faroe Islands and compared to n=414 men from Greenland, Ukraine and Poland. Infertile men n=190 were enrolled at a fertility clinic in Denmark and androgenicity in smoking men was measured in n=2156 men recruited for several previous epidemiological studies. The effect of smoking was assessed in a reporter system with the prostate specific antigen promoter driving a luciferase gene, in the presence or absence of various concentrations of the cigarette smoke constituent Benzo[α]Pyrene (BaP). In men from the Faroe Islands, the Y:X ratio was lower than in other highly exposed populations and a negative association between the sperm sex chromosome ratio and both dichlorodiphenyl dichloroethane (DDE) and selected polychlorinated biphenyls (PCBs) in the somewhat older, proven fertile men was found. A positive trend between the Y:X ratio and perfuorooctane sulfonate (PFOS) in a combined population of men from Greenland, Ukraine and Poland was found. The opposite association was observed in the Greenland Inuit alone. In subfertile men, a positive association between the Y:X ratio and progressive motility was noted. In two cohorts of smoking men, positive trends between groups of men with increasing exposure to cigarette smoke and androgen insensitivity was found. The in vitro experiments showed a significant deactivation of the AR at the highest BaP concentration. To conclude, high concentrations of EDCs influence the Y:X ratio in highly exposed populations i.e. men from Greenland and the Faroe Islands. The inter-population differences in Y:X ratio might be genetic or due to lifestyle factors such as diet. Men with low progressive motility had lower Y:X ratio, possibly explaining the low birth sex ratio seen following intra cytoplasmic sperm injection. Indications that smoking has adverse effects on the androgenicity were observed both in vivo and in vitro.
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