Impact of PCB and p,p′-DDE Contaminants on Human Sperm Y:X Chromosome Ratio: Studies in Three European Populations and the Inuit Population in Greenland

Autor: Lars Rylander, Marcello Spanò, Davide Bizzaro, Bo Jönsson, Aleksander Giwercman, Tarmo Tiido, Valentyna Zvyezday, Gunnar Toft, Bogdan Wojtyniak, Jens Peter Bonde, Eva Cecilie Bonefeld-Jørgensen, Henning S. Pedersen, Anna Rignell-Hydbom, Jan K Ludwicki, Lars Hagmar, Yvonne Lundberg Giwercman, Vladimir Lesovoy, Gian Carlo Manicardi
Jazyk: angličtina
Rok vydání: 2005
Předmět:
Zdroj: Environmental Health Perspectives
ISSN: 1552-9924
0091-6765
Popis: Recent studies have indicated that the proportion of male births has been declining in many countries during the past five decades (Allan et al. 1997; Marcus et al. 1998; Moller 1998; Parazzini et al. 1998; van der Pal-de Bruin et al. 1997). The cause of such a time-related trend is not known but has been suggested to result from an increasing exposure to endocrine disruptors such as persistent organohalogen pollutants (POPs) (Toppari et al. 1996). POPs—for example, polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated biphenyls (PCBs), dichlorodiphenyl-trichloroethane (DDT), and dichloro-diphenyldichloroethene (p,p′-DDE), the most stable metabolite of DDT—are ubiquitous environmental contaminants. Because of the hydrophobic and lipophilic nature and their long half-lives, these compounds are highly persistent and have a tendency to bio-accumulate and biomagnify in the food chain. Studies have shown that measurable levels of PCBs and p,p′-DDE are found in a large proportion of the general population [Arctic Monitoring and Assessment Programme (AMAP) 2003; Longnecker et al. 1997]. Some of these POPs can disrupt multiple endocrine pathways and induce a wide range of toxic responses (Toppari et al. 1996). A number of studies have demonstrated their estrogenic, antiestrogenic, dioxin-like, and androgen-competing properties (Andersen et al. 2002; Bonefeld-Jorgensen et al. 2001; Danzo 1997). Dioxin toxicity is most potent when animals are exposed in utero and lactationally. Although single exposure to dioxin has been investigated in a number of studies, there are few reports on repeated exposure of low dioxin doses, which more resembles the human situation. Recently, Ikeda et al. (2005) showed that in utero and lactational exposure of male rats to dioxin decreased the sex ratio of the subsequent generation. With respect to human exposure, two accidents that have attracted scientific and public attention are the Yucheng poisoning (Chen et al. 1985; Masuda et al. 1985) and the Seveso disaster (Mocarelli et al. 1996), both of which were associated with an increased proportion of girls born subsequent to paternal exposure to POPs (del Rio Gomez et al. 2002; Mocarelli et al. 1996, 2000). In human populations exposed to more moderate levels of POPs, both increased (Karmaus et al. 2002) and decreased (Rylander et al. 1995) male:female sex ratios have been reported. Therefore, the explanation of the secular trend in sex ratio is still lacking, and the mechanisms that can affect the proportion of males to females are not yet understood. Theoretically, offspring sex ratio may be related to events that occur before fertilization that favor selection of Y- or X-chromosome–bearing spermatozoa, events that occur after fertilization such as preferential development or survival of embryos of one sex, or a combination of both. Although recent human studies have indicated that paternal exposure to POPs has a deleterious effect on some semen characteristics (Guo et al. 2000; Hauser et al. 2003; Richthoff et al. 2003; Rignell-Hydbom et al. 2005), it is not yet known whether these compounds could change the proportion of X- and Y-bearing sperm. Recently, in a population composed of Swedish fishermen, we found a moderate positive association between serum levels of PCB-153 and of p,p′-DDE and the proportion of Y-bearing spermatozoa (Tiido et al. 2005). The study was part of a European Union–supported collaboration (INUENDO 2006) aiming to enlighten the impact of POP exposure on human reproductive function. Other populations included in this collaboration were recruited from Greenland, Poland (Warsaw), and Ukraine (Kharkiv). We have chosen to use the PCB congener, 2,2′,4,4′,5,5′-hexachloro-biphenyl (PCB-153) as a biomarker for POP exposure because of its very high correlations with the total PCB concentration (Glynn et al. 2000; Grimvall et al. 1997), the estimated 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) equivalent (TEQ) from PCB, and the total POP-derived TEQ (Gladen et al. 1999), respectively. Likewise, the major DDT metabolite p,p′-DDE, an antiandrogenic compound, is another good indicator of the exposure. Previous studies from Greenland, Ukraine, and Sweden indicate that the exposure levels for p,p′-DDE are still considerable (Deutch et al. 2004; Gladen et al. 1999; Sjodin et al. 2000). The aim of the present study was to investigate whether the previously reported positive association between POP exposure markers and the proportion of Y-bearing sperm also occurs in three other populations characterized by different POP exposure profiles than the one found among Swedish fishermen (Jonsson et al. 2005). This information might indirectly add to our understanding of the biologic link between POP exposure and offspring sex ratio.
Databáze: OpenAIRE
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