Effect of cumulus cells and sperm concentration on fertilization and development of pig oocytes

Effect of sperm concentrations and cumulus cells (CCs) on porcine IVF was re-evaluated using current improved IVM and IVC system. Our results showed that both CCs and sperm concentration had significant effect on penetration rate, frequency of polyspermy and embryonic development. The best IVF results were obtained with oocytes with CCs fertilized with 0.5 × 10⁵ sperm/ml. Such an IVP system works on both sow and gilt oocytes.

Discharge diagnoses of liver diseases in Nuuk Greenland compared to a Danish county hospital

BACKGROUND

It is a frequently held notion that Inuits/Greenlanders are less prone to develop chronic liver disease than Europeans. High alcohol consumption and chronic viral infection are more frequent in Greenland than in Denmark.

STUDY DESIGN

A cross-sectional study to examine the incidence and prevalence of liver discharge diagnosis with focus on cirrhosis among hospital-admitted patients in Greenland and Denmark.

METHODS

Register-based ICD-10 discharge diagnoses from Queen Ingrid's Hospital, Greenland, (n = 1072) and Randers Central Hospital, Denmark, (n = 4599) were used to compare the incidence and prevalence of cirrhosis in hospitalised patients during 1998.

RESULTS

Five patients (0.47%) in Greenland and 36 (0.78%) in Denmark had a liver discharge diagnosis (OR = 0.67, 95% CI: 0.26-1.72). Two patients (0.19%) in Greenland compared to 25 (0.54%) in Denmark had a cirrhosis associated discharge liver diagnosis (OR = 0.34, 95% CI: 0.08-1.45). The number of newly diagnosed discharged patients was smaller in Greenland, 2 (0.19%), vs. Denmark, 14 (0.30%), (OR = 0.61, 95% CI: 0.14-2.70).

CONCLUSION

Discharge liver diagnoses were not more frequent in Greenland than in Denmark--if anything, the hospital prevalence and incidence of liver discharge diagnoses were lower. This may reflect fewer cirrhosis cases in Greenland, and/or a shorter survival time, or lack of follow up.

Very high concentrations of n-3 fatty acids in peri-and postmenopausal Inuit women from Greenland

OBJECTIVES

The objectives of this study were to examine the profile of relative concentrations in plasma phospholipids of n-3 fatty acids among peri- and postmenopausal Inuit women living in Greenland and to verify their relationships with ischemic heart disease risk factors and more particularly, with concentrations of plasma triacylglycerols.

STUDY DESIGN

This study was part of a survey conducted in 2000, which aimed to assess the prevalence of osteoporosis and the associated risk factors among peri- and postmenopausal Greenland Inuit women.

METHODS

The study population consisted of 153 women aged 49-69 years (mean +/- SD: 55.3 +/- 4.4 y) randomly selected. Data were obtained through an interview (questionnaire on lifestyle habits, medical history etc) and a clinical session (physiologic and anthropologic measurements). Plasma samples were used to measure the fatty acid composition of plasma phospholipids.

RESULTS

The mean body mass index of women was 27.9 +/- 6.1. Seventy-five percent were smokers and 9% were currently on hormone replacement therapy. Relative concentrations of total n-3 fatty acids were very high (13.8%, 95% CI: 13.1-14.6), with docosahexanoic and eicosapentanoic acids accounting for 4.7% and 7.2%, respectively. The ratio of n-3:n-6 fatty acids was 0.67. n-3 fatty acids were inversely correlated to triacylglycerols.

CONCLUSION

These data show that peri- and post-menopausal Greenland Inuit women have very high plasma concentrations of n-3 fatty acids that protect them from ischemic heart disease.

Increasing overweight in Greenland: social, demographic, dietary and other life-style factors

OBJECTIVES

In several Arctic countries, weight gain is very evident among the local populations and the percentages of overweight and obese persons are increasing rapidly. Since the development of overweight among the Arctic populations seems to coincide with the westernization of their diet and other life-style factors, it is tempting to hypothesize that the transition to carbohydrate- and fat-rich western food causes the weight gain. The high relative content of (n-3) fatty acids in traditional foods presumably provides some protection against cardiovascular diseases, type 2 diabetes and various other diseases of affluent industrialized societies. In the present study, we have investigated the recent weight gain in Greenland and have tried to relate it to social factors, present dietary habits and other life-styles.

STUDY DESIGN

The cross-sectional study, which was part of the Arctic Monitoring and Assess Programme, included 410 men and women (18-49 years) from 5 districts in Greenland. It was based upon questionnaires including a dietary survey, anthropometric measurements and blood lipid analyses.

RESULTS

Obesity (Body Mass Index (BMI) > 30 kg/m2, corresponding to about 19% of the participants) increased with age, was most prevalent among higher household economic levels, and correlated with neither local, nor imported food intake.

CONCLUSION

Overweight was not found to be correlated with either western, or traditional food composition. Obesity had adverse effects on several health indicators, serum triglyceride, HDL and the cardiovascular risk index, (Chol-HDL)/HDL and TG/HDL, counteracting the positive effects of (n-3) fatty acids and should be considered as a serious health risk for the Greenlandic population.

Exposure to persistent organic pollutants and sperm DNA methylation changes in Arctic and European populations

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.

Lifestyle, reproductive factors and food intake in Greenlandic pregnant women: the ACCEPT - sub-study

Background

In the past decades, Greenland has changed from a hunter society to a more western lifestyle, causing less intake of traditional food, such as marine mammals, fish and seabirds. These changes in the living conditions and food habits might impact the maternal health in Greenland.

Objectives

To describe lifestyle, reproductive factors and food intake in Greenlandic pregnant women, and to assess possible age and geographical differences.

Design

Cross-sectional study of 189 Greenlandic pregnant women. Inclusion criteria were ≥18 years and lived >50% of their life in Greenland. Data were collected in 2010–2011, and information was obtained from lifestyle and food frequency questionnaires. Two age groups for comparison were given for the pregnant women (<27 years vs. ≥27 years) with regard to the median age. Region groups for comparison were West, Disko Bay, South, North and East.

Results

Population characteristics showed that 43.3% had pre-pregnancy body mass index (BMI) >25.0 kg/m², 46.3% were current smokers in the beginning of their pregnancy and few participants consumed alcohol during pregnancy. Women <27 years were more in doubt regarding planned breastfeeding period and consumed more dried fish and fast food. A trend for higher alcohol intake during pregnancy was found for women ≥27 years. The regional differences showed that women living >50% in North, South and West had a higher alcohol intake during pregnancy. Women in North had the fewest breastfeeding plans. Women in Disko Bay had the lowest intake of terrestrial species. No significant geographical differences were found for intake of marine mammals or seabirds.

Conclusions

The present study found relatively high BMI level and high smoking frequency in Greenlandic pregnant women. Age and region differences were found for alcohol consumption, breastfeeding plans and food intake profile. Further research is needed to implement relevant maternal health intervention programs in Greenland.

Hazard quotient profiles used as a risk assessment tool for PFOS and PFOA serum levels in three distinctive European populations

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) blood levels are commonly used as biomarkers of human environmental exposure to these compounds. Many biomonitoring studies indicate 100% detection for PFOS and PFOA thus justifying a concern of possible risk for the most exposed individuals. This study addresses the predictive value of hazard quotients (HQs) calculated on the basis of serum PFOS and PFOA in male and female populations of reproductive age in Greenland, Poland and Ukraine. Overall, 2026 results of PFOS and PFOA serum concentrations (589 males, 1437 females) were obtained from the INUENDO database. HQs were calculated from the actual biomonitoring results and literature-based animal data linking toxicological outcomes and critical PFOS/PFOA serum levels. HQs for serum PFOS were calculated based on Points of Departure (PoD) at 13μgmL(-1) (cynomolgus monkeys, 183days, changes in THS and T3) and for PFOA at 7.1μgmL(-1) serum (male rats, 90days, hepatocellular necrosis, increased liver weight). Uncertainty factors were applied to reflect interspecies differences and human variability. Serum HQs were expressed as a ratio relative to the point of departure for each PFOS and PFOA. Only in the three cases of males in Greenland were there serum PFOS levels showing HQ values exceeding 1, so indicating that such serum levels may be of concern. The mean serum concentration of PFOS was significantly higher in male than in female populations. Despite significant differences between HQ profiles for PFOS and PFOA in donors from Greenland, Poland and Ukraine, the concentrations of these perfluoroalkylated compounds do not indicate a cause for concern, except for the three aforementioned cases from Greenland. This study demonstrates that the HQ approach can help to interpret human biomonitoring data and thus serve as a valuable tool in further risk assessment priority settings and may also be used as a basis for taking decisions in risk management.

Impact of moderate interval exercise versus supine rest on the pharmacokinetics and pharmacodynamic profiles of subcutaneously administered growth hormone in adult growth hormone deficient patients

BACKGROUND

Diurnal variation in serum growth hormone (s-GH) levels after exogenous GH delivery has previously been reported in patients with no endogenous GH secretion. Changes in postural position or physical activity, leading to changes in blood flow and/or lymphatic drainage may be underlying explanations.

PRIMARY OBJECTIVES

The primary aim of this study is to study a possible impact of exercise and supine rest on pharmacokinetics (PK) and day-to-day variation of subcutaneously (s.c.) administered GH in adult GH deficient (AGHD) patients.

SECONDARY OBJECTIVE

The secondary aim of this study is to compare s-IGF-I, s-insulin, and plasma (p)-glucose profiles after a carbohydrate rich breakfast following s.c. GH injection vs. continuous infusion.

DESIGN AND METHODS

During supine rest eight AGHD males (59.8±8 years, BMI 29.7±4.9 kg/m(2)) were treated with one daily s.c. GH injections of 3 mg/24 h for 48 h (treatment sessions A, B) or a continuous s.c. GH infusion of 3 mg/24 h for 60 h (treatment sessions C, D). Exercise comprised 1 h bicycling with 50 W load on two consecutive days during treatment sessions B and D.

RESULTS

Administration of GH as a bolus injection, but not as a continuous GH infusion, resulted in about 32% higher s-GH levels during exercise (60 min) as well as 30 min after (s-GH logAUC(B-A) difference was 0.28; 95% CI: 0.14-0.4; p<0.001). However, the total s-GH(AUC 0-24 h) (p=0.75) and s-IGF-I(AUC0-48 h) levels (p=0.51) remained unchanged between the two occasions. P-glucose and insulin profiles were significantly higher after carbohydrate rich breakfast before first and second dosing both following s.c. GH injection and continuous infusion (p<0.05).

CONCLUSIONS

Moderate exercise intermittently increased s-GH levels. These changes seem to have no clinical short-term relevance, since total s-GH(24 h) and s-IGF-I(48 h) levels were unaffected.

Exposure to perfluoroalkyl substances and sperm DNA global methylation in Arctic and European populations

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, Satα) 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 hyper-methylation 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.

Serum concentrations of polybrominated diphenyl ethers (PBDEs) and a polybrominated biphenyl (PBB) in men from Greenland, Poland and Ukraine

Many brominated flame retardants (BFRs)-including polybrominated diphenyl ethers (PBDEs)-have been shown to persist in the environment, and some have been associated with adverse health effects. The aim of the present study was to quantify serum concentrations of common brominated flame retardants in Inuit men from across Greenland, and in men from Warsaw, Poland and Kharkiv, Ukraine. Serum was sampled between 2002 and 2004 from men 19 to 50years of age. 299 samples were analyzed for BDE-28, 47, 99, 100, 153, 154 and 183 and the brominated biphenyl BB-153 using gas chromatography-high resolution mass spectrometry. BDE-47 and BDE-153 were detected in more than 95% of samples from all three populations. All other congeners, except BDE-154, were detected in more than 70% of samples from Greenland; lower detection frequencies were observed in Polish and Ukrainian samples. Concentrations of individual congeners were 2.7 to 15 fold higher in Greenlandic relative to Polish and Ukrainian men. Geometric mean concentrations of the sum of the most abundant PBDEs of the Penta-BDE commercial mixture (BDE-47, 99, 100, 153 and 154) were 6.1, 1.7 and 0.87ng/g lipids in the Greenlandic, Polish and Ukrainian men, respectively. Furthermore, significant geographical differences in BFR concentrations were observed within Greenland. Principal component analysis revealed distinct clustering of samples by country of origin. The associations between ΣPBDEs and age were inconsistent, varying from no association in Greenlandic and Polish study populations to a U-shaped relationship in Ukrainians. We report BFR levels for three populations for which sparse biomonitoring data exists.

Polyunsaturated fatty acids and calcaneal ultrasound parameters among Inuit women from Nuuk (Greenland): a longitudinal study

BACKGROUND

The traditional diet of Inuit people comprises large amounts of fish and marine mammals that are rich in omega-3 polyunsaturated fatty acids (PUFAs). Results from in vitro studies, laboratory animal experiments and population studies suggest that omega-3 PUFA intake and a high omega-3/omega-6 ratio exert a positive effect on bone health.

OBJECTIVE

This longitudinal study was conducted to examine the relationship between omega-3 and omega-6 PUFA status and quantitative ultrasound (QUS) parameters in Greenlandic Inuit women.

METHODS

The study included 118 Inuit women from Nuuk (Greenland), aged 49-64 years, whose QUS parameters measured at baseline (year 2000), along with PUFA status and covariates, and follow-up QUS measurements 2 years later (year 2002). QUS parameters [speed of sound (SOS); broadband ultrasound attenuation (BUA)] were measured at the right calcaneus with a water-bath Lunar Achilles instrument. Omega-3 and omega-6 PUFA contents of erythrocyte membrane phospholipids were measured after transmethylation by gas chromatography coupled with a flame ionization detector. Relationships between QUS parameters and different PUFAs were studied in multiple linear regression models.

RESULTS

Increasing values of EPA, DHA and the omega-3/omega-6 PUFA ratio were associated with increased BUA values measured at follow-up (year 2002). These associations were still present in models adjusted for several confounders and covariates. We found little evidence of associations between PUFAs and SOS values.

CONCLUSION

The omega-3 PUFA intake from marine food consumption seems to have a positive effect on bone intrinsic quality and strength, as revealed by higher BUA values in this group of Greenlandic Inuit women.

Non-linear association between androgen receptor CAG and GGN repeat lengths and reproductive parameters in fertile European and Inuit men

Recently the dogma that there is an inverse linear association between androgen receptor (AR) CAG and GGN polymorphisms and receptor activity has been challenged. We analysed the pattern of association between 21 male reproductive phenotypes and AR CAG/GGN repeat lengths in 557 proven-fertile men. A linear association was only found between sperm DNA fragmentation index (DFI) and CAG length, and between inhibin B and GGN length. Men with longer CAG then the reference (22-24), had higher oestradiol levels, whereas men with shorter CAG stretches had a higher DFI and a higher proportion of Fas-positive germ cells. Subjects with either short or long CAG had increased seminal levels of prostate-specific antigen and neutral α-glucosidase activity. Compared to men with the median GGN length of 23, those with shorter GGN repeats had higher levels of inhibin B, higher proportions of normal and progressive sperm, and a higher fraction of Fas-positive sperm, while men with longer GGN had higher oestradiol levels. These data indicate that at least for some markers of male reproductive function the association with CAG or GGN repeat length is curvilinear.

Serum levels of perfluorinated compounds and sperm Y:X chromosome ratio in two European populations and in Inuit from Greenland

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.

Blood serum concentrations of perfluorinated compounds in men from Greenlandic Inuit and European populations

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA), are used in large quantities. They are persistent and found in measurable levels in human serum around the world. They have been associated with developmental, hepatic, and carcinogenic effects in animal studies. The aim of the present study was to describe levels of PFCs in serum among Inuits from Greenland and inhabitants from Warsaw, Poland and Kharkiv, Ukraine. Furthermore, the aim was to define social- and lifestyle related determinants of exposure for these compounds. Serum levels of seven PFCs were analyzed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The concentrations of PFOS and PFOA were the highest of all PFCs in all three populations with a total amount of almost 90% of the PFCs. The mean levels of PFOS and PFOA were in the Greenlandic Inuits 52 and 4.8 ng mL(-1), in Poland 19 and 5.2 ng mL(-1), and in Ukraine 8.1 and 1.9 ng mL(-1), respectively. Thus, levels of PFCs in the serum of Inuits on Greenland were among the highest described in a general population whereas the levels in Poland were similar to other industrialized countries. The exposure in Ukraine was rather low. In the Greenlandic Inuit population, intake of seafood, tea, age and area of living were significant determinants of PFOS concentrations and explained about 22% of the variation. For the other populations no strong determinants were found.

Association of maternal serum concentrations of 2,2', 4,4'5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis (p-chlorophenyl)-ethylene (p,p'-DDE) levels with birth weight, gestational age and preterm births in Inuit and European populations

BACKGROUND

Epidemiological studies on the association between maternal exposure to persistent organic pollutants (POPs) and fetal growth alteration report inconsistent findings which weights in favor of additional studies.

METHODS

Blood samples were collected from interviewed pregnant women in Greenland (572), Kharkiv (611) and Warsaw (258) and were analyzed for CB-153 and p,p'-DDE by gas chromatography-mass spectrometry. Data on birth weight, gestational age and preterm birth were obtained for 1322 singleton live births. We examined the association between natural log-transformed serum POPs concentration and birth weight and gestational age using multiple linear regression and the association with prematurity using logistic regression controlling for potential confounding factors.

RESULTS

The median serum concentrations of CB-153 and p,p'-DDE were for Inuit mothers 105.6 and 298.9, for Kharkiv mothers 27.0 and 645.4 and for Warsaw mothers 10.7 and 365.2 ng/g lipids, respectively. Increase in CB-153 concentration by one unit on the log scale in Inuit mothers serum was associated with significant decrease in infant birth weight of -59 g and gestational age by -0.2 week. Decreases observed in the cohorts in Kharkiv (-10 g and -0.1 week) and in Warsaw (-49 g and -0.2 week) were not statistically significant. Increase in p,p'-DDE concentration by one unit on the log scale was associated with a statistically significant decrease in infant birth weight of -39.4 g and -104.3 g and shortening of gestational age of -0.2 week and -0.6 week in the Inuit and Warsaw cohorts, respectively. In the Kharkiv cohort decrease in birth weight (-30.5 g) was not significant, however a shortening of gestational age of -0.2 week per increase in p,p'-DDE concentration by one unit on the log scale was of the borderline significance. There was no significant association between CB-153 and p,p'-DDE concentrations and risk of preterm birth however, in all cohorts the odds ratio was above 1.

CONCLUSIONS

In utero exposure to POPs may reduce birth weight and gestational age of newborns however, new insights as to why results vary across studies were not apparent.

Fetal loss and maternal serum levels of 2,2',4,4',5,5'-hexachlorbiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) exposure: a cohort study in Greenland and two European populations

BACKGROUND

In the present study, the aim is to examine the risk of fetal loss related to environmental 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) or 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene (p,p'-DDE) exposure.

METHODS

We related LC/MS/MS measurements of CB-153 and p,p'-DDE in serum samples to interview-data on previous fetal loss in populations of pregnant women from Poland, Ukraine and Greenland.

RESULTS

In total, 1710 women were interviewed, and 678 of these had at least one previous pregnancy. The risk of ever experiencing a fetal loss increased at higher levels of CB-153 and p,p'-DDE exposure, with an adjusted odds ratio (OR) of 2.4; confidence interval (CI) (1.1-5.5) for CB-153>200 ng/g lipid compared to 0-25 ng CB-153/g lipid and OR of 2.5 CI (0.9-6.6) for p,p'-DDE>1500 ng/g lipid compared to 0-250 ng DDE/g lipid. However, no clear dose response associations were observed. The results further suggest that high level of organochlorine serum concentrations may be related to repeated loss.

CONCLUSIONS

The risk of fetal loss may increase at higher levels of CB-153 and p,p'-DDE exposure, although lack of dose response and inconsistencies between countries did not allow for firm conclusions.

Semen quality in relation to xenohormone and dioxin-like serum activity among Inuits and three European populations

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.

Xenoandrogenic activity in serum differs across European and Inuit populations

BACKGROUND

Animal and in vitro studies have indicated that human male reproductive disorders can arise as a result of disrupted androgen receptor (AR) signalling by persistent organic pollutants (POPs). Our aim in the present study was to compare serum xenoandrogenic activity between study groups with different POP exposures and to evaluate correlations to the POP proxy markers 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(p-chlorophenyl)-ethylene (p,p'-DDE).

METHODS

We determined xenoandrogenic activity in the serum fraction containing the lipophilic POPs but free of endogenous hormones. Adult male serum (n = 261) from Greenland, Sweden, Warsaw (Poland), and Kharkiv (Ukraine) was analyzed. Xenoandrogenic activity was determined as the effect of serum extract alone (XAR) and in the presence of the synthetic AR agonist R1881 (XARcomp) on AR transactivated luciferase activity.

RESULTS

The study groups differed significantly with respect to XARcomp activity, which was increased in the Inuits and decreased in the European study groups; we observed no difference for XAR activity. We found the highest level of the AR antagonist p,p'-DDE in Kharkiv, and accordingly, this study group showed the highest percent of serum samples with decreased XARcomp activities. Furthermore, the percentage of serum samples with decreased XARcomp activities followed the p,p'-DDE serum level for the European study groups. No correlations between serum XAR or XARcomp activities and the two POP markers were revealed.

CONCLUSIONS

The differences in XARcomp serum activity between the study groups suggest differences in chemical exposure profiles, genetics, and/or lifestyle factors.

Androgen receptor gene CAG repeat length as a modifier of the association between persistent organohalogen pollutant exposure markers and semen characteristics

OBJECTIVES

Exposure to persistent organohalogen pollutants was suggested to impair male reproductive function. A gene-environment interaction has been proposed. No genes modifying the effect of persistent organohalogen pollutants on reproductive organs have yet been identified. We aimed to investigate whether the CAG and GGN polymorphisms in the androgen receptor gene modify the effect of persistent organohalogen pollutant exposure on human sperm characteristics.

METHODS

Semen and blood from 680 men [mean (SD) age 34 (10) years] from Greenland, Sweden, Warsaw (Poland) and Kharkiv (Ukraine) were collected. Persistent organohalogen pollutant exposure was assessed by measuring serum levels of 2,2',4,4',5,5'-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p'-DDE). Semen characteristics (volume, sperm concentration, total count, proportion of progressively motile and morphology) and DNA fragmentation index (DFI) were determined. CAG and GGN repeat lengths were determined by direct sequencing of leukocyte DNA.

RESULTS

A statistically significant interaction was found between the CB-153 group and CAG repeat category in relation to sperm concentration and total sperm count (P=0.03 and 0.01, respectively). For p,p'-DDE, in the European cohorts a significant interaction was found in relation to DFI (P=0.01). For CAG<20, sperm concentration and total sperm count were 35 and 42% lower, respectively, when the group with CB-153 exposure above median was compared with that below the median. DFI was 40% higher in the high p,p'-DDE exposure group for CAG<or=21.

CONCLUSIONS

This study indicated that the androgen receptor CAG repeat length might modify the susceptibility of an individual to the adverse effects of persistent organohalogen pollutant exposure on semen quality. Other studies regarding this matter are warranted.

Relationships between sperm DNA fragmentation, sperm apoptotic markers and serum levels of CB-153 and p,p′-DDE in European and Inuit populations

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 pro-apoptotic (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 be investigated in order to fully assess the population variations observed.

Reproductive hormone levels in men exposed to persistent organohalogen pollutants: a study of inuit and three European cohorts

OBJECTIVE

Persistent organohalogen pollutant (POP) exposure may have a negative impact on reproductive function. The objective of this study was to assess the impact of POP exposure on the male hypothalamo-pituitary-gonadal axis.

PARTICIPANTS

Participants included 184 Swedish fishermen and spouses of pregnant women from Greenland (n = 258), Warsaw, Poland (n = 113) , and Kharkiv, Ukraine (n = 194).

EVALUATIONS/MEASUREMENTS

Serum levels of 2,2,4,4,5,5-hexachlorobiphenyl (CB-153) and dichlorodiphenyl dichloroethene (p,p -DDE) were determined in the four populations, showing different exposure patterns: Swedish fishermen, high CB-153/low p,p -DDE; Greenland, high CB-153/high p,p -DDE; Warsaw, low CB-153/moderate p,p -DDE; Kharkiv, low CB-153/high p,p -DDE. Serum was also analyzed for testosterone, estradiol, sex hormone-binding globulin (SHBG) , inhibin B, luteinizing hormone (LH) , and follicle-stimulating hormone (FSH) . Free testosterone levels were calculated based on testosterone and SHBG.

RESULTS

We found significant center-to-center variations in the associations between exposure and the outcomes. The most pronounced effects were observed in Kharkiv, where statistically significant positive associations were found between the levels of both CB-153 and p,p -DDE and SHBG, as well as LH. In Greenland, there was a positive association between CB-153 exposure and LH. In the pooled data set from all four centers, there was positive association between p,p -DDE and FSH levels [beta = 1.1 IU/L; 95% confidence interval (CI), 1.0-1.1 IU/L]. The association between CB-153 levels and SHBG was of borderline statistical significance (beta = 0.90 nmol/L; 95% CI, -0.04 to 1.9 nmol/L).

CONCLUSIONS

Gonadotropin levels and SHBG seem to be affected by POP exposure, but the pattern of endocrine response is the subject of considerable geographic variation.

Remarkably low incidence of hypospadias in Greenland despite high exposure to endocrine disrupters; possible protective effect of androgen receptor genotype

Endocrine disrupters, such as persistent organohalogen pollutants (POPs) may cause hypospadias, which is a common congenital anomaly in males, affecting 0.2-0.7%. We hypothesized that hypospadias incidence would be high among Greenlanders, who are one of the most POP exposed populations on earth through consumption of contaminated sea mammals. Interestingly, among the 11 076 boys born in Greenland 1982-2002, only two cases of hypospadias were noted (incidence 0.02%; 95% CI: 0.002-0.06). Normal male sexual differentiation is dependent on the androgen receptor (AR). AR function is regulated by polymorphic repeats of CAG and GGN trinucleotide bases. In Greenland 85% were carriers of GGN=23, which in a previous report was less frequent in patients with hypospadias than in the general population. This finding indicates that AR genotype could contribute to a genetic predisposition in Greenlanders, who despite one of the worlds highest body burden of POPs, seem to be protected from hypospadias.

Association between exposure to persistent organohalogen pollutants and epididymal and accessory sex gland function: multicentre study in Inuit and European populations

Exposure to persistent organochlorine pollutants (POPs) may have negative impact on male reproductive function. We, therefore, investigated the association between serum levels of POPs and epididymal and accessory sex gland function. Serum levels of CB-153, p,p'-DDE and seminal markers of epididymal [neutral-alpha glucosidase (NAG)], prostatic [prostate specific-antigen (PSA)] and zinc, and seminal vesicle function (fructose) were measured from 135 Swedish fishermen and fertile men from Greenland (n=163), Warsaw, Poland (n=167) and Kharkiv, Ukraine (n=158). Multiple linear regression analyses, adjusting for potential confounders, were employed using both continuous and categorized exposure variables. Both exposure and outcome variables were log transformed. Considering the consistency between models with either continuous or categorized CB-153 levels, negative associations with the activity of NAG were found among Greenlandic men (mean difference 7.0 mU/ejaculate, 95% CI 3.0, 34), and in the aggregated cohort (mean difference 4.0 mU/ejaculate, 95% CI -0.2, 8.0). A positive association was observed between CB-153 and PSA as well as zinc among Kharkiv men. In the Swedish cohort, a negative association was found between CB-153 and fructose. In conclusion, the negative effects of POP on sperm motility, observed in the same study population might partly be caused by post-testicular mechanisms, involving a decreased epididymal function.