P-411 Blood concentrations of specific (PCBs) congeners and abortion rates in healthy women undergoing IVF cycles living in areas with high and low pollution. (EcoFoodFertility Project)

Study question

Human exposure to polychlorinated biphenyls (PCBs) exists despite its ceased production since 1977. PCBs congeners harm reproductive health, but data remain inconclusive.

Summary answer

Evaluate relationship between blood concentrations of specific (PCBs) congeners and abortion rates in women undergoing IVF cycles living in areas with high and low pollution.

What is known already

PCBs are a class of synthetic chemicals that were widely used in industry until the 1970s and are found in many consumer products as refrigerants in electrical equipment, as flame retardants in plastics production and electronics. Continuous exposure to PCBs is of concern because they fall into the group of endocrine disruptors (EDCs), PCB congeners can spread throughout the female reproductive tract. Indeed, they have been found in human follicle fluids, placenta, amniotic fluid in embryos and fetuses Despite multiple reproductive health effects in women was reported, the results are sometimes inconsistent between experimental and epidemiological studies.

Study design, size, duration

In the frame of EcoFoodFertility Project, a cross sectional study conducted in Campania Region (Italy) to assess environmental impact on fertility and human health, blood samples were collected during the IVF cycles of the 65 women (aged 27.8 + 3.6) no smokers, BMI 23.5 – 27.9, normal menstruation, in two areas with high and low pollution between 2017 and 2019. The PCBs congeners we investigated were: estrogenic congeners (31,44,52,101,153), anti-estrogenic congeners (77,105,110,114,126,156,169) and other (28,118,138,180).

Participants/materials, setting, methods

Group A (n = 30) living in low polluted area (LPA), alto Medio Sele in province of Salerno, and group B (n = 35) living in highly polluted area (HPA), known as the “Land of Fires” due to the many sources of pollution. The blood sample was taken on the day of the oocyte pick-up and PCBs were measured by Gas Chromatography Coupled to (tandem) Mass Spectrometry. Statistical analyses were performed by GraphPad Prism 9.

Main results and the role of chance

Blood concentrations of PCBs are expressed as wet weight (nanograms per gram of serum) and as standardised lipid concentrations (nanograms per gram lipid). The PCB 169 congener was found in the highest concentration, 229.62 ng/g and, on average, accounted for 46.2 % of ΣPCBs tested. The PCB 77 (p < 0.05) and 118 ((p < 0.001) congeners were significantly higher in participants permanently living in HPA (Group B). For the other congeners, no significant variation was found. No significant variations between the two groups for oocyte pick-up rate, metaphase I and II oocyte ratio was found, fertilisation rate and pregnancy rate. Furthermore, the probability of embryo implantation was similar between the two groups, but the abortion rate was 3.0 times higher in group B. The probability of live births is 85.7% in group A and 53.85% in group B.These findings, even if the results between PCBs exposure and reproductive outcomes are due to the different congeners of these chemical compounds and unknown confounding factors and exposure times may be implicated, however suggest an association between the detection of specific PCB congeners and increased abortion rates in women undergoing IVF cycles that cannot be understimated.

Limitations, reasons for caution

Although we have set up a strict control and survey protocol, our study also has limitations due to the relatively small sample size of the groups and as with almost all epidemiological studies on environmental impact, there may be confounders or co-exposures that could interfere with the observed associations.

Wider implications of the findings

Although PCBs are no longer produced, the exposure remains widespread due to their long biological half-life, accumulation in the food chain and human health impacts are still reported. Our findings confirm these concerns, therefore, the study of these old chemicals is still relevant and important and should be expanded.

Trial registration number

not applicable

O-286 Bisphenol A in blood serum and follicular fluid of women undergoing to cycle of IVF living in areas with different environmental impact. (EcoFoodFertility Project)

Study question

Bisphenol A (BPA) is a constituent of polycarbonate and epoxy resin plastics and is also a by-product of combustion of plastics, resulting harmful for health.

Summary answer

To evaluate the presence of BPA in the blood and Follicular Fluids, in women, subjected to IVF cycles, living in areas with different environmental impact.

What is known already

BPA is used in the production of polycarbonate plastics and epoxy resins. 1,3,5-triphenylbenzene is a tracer for burning plastic and has been related to levels of bisphenol A in the air, so the actual release of bisphenol A to the atmosphere could result from burning the plastic. Bisphenol A belongs to the group of endocrine disruptors.

Little is known about the effects of BPA on human female reproduction. BPA levels appear to be inversely related to the number of oocytes retrieved in IVF cycles, and it also appears to negatively affect the ovulatory peak of estradiol.

Study design, size, duration

In the frame of EcoFoodFertility project a cross sectional study conducted in Campania Region (Southern Italy), between January 2019 and December 2020, 74 women, no smokers, no chronic diseases, not exposed to occupational risk factors. living for at least 5 years in areas with low environmental impact (LEI, 31 women), Alto-Medio Sele in province of Salerno and high environmental impact (HEI, 43 women), so-called “Land of Fires” in province of Naples, were selected.

Participants/materials, setting, methods

Participants have a normal ovarian reserve, average age 32.05 + 3.49, with infertility duration between 26 and 39 months and at the first experience of an IVF cycle. ELISA was used for measuring bisphenol A in blood and Follicular Fluids (FFs), expressed in ng/ mL. 5 mL glass tubes, without additives, not siliconized and kept in a horizontal position were used. FFs were bloodless with a negative albumin test.

Main results and the role of chance

Differents levels of BPA were found in all processed samples.

In the LEI (Low Environmental Impact) group, serum levels vary from a minimum of 3.1 ng/mL to a maximum of 7.7 ng/mL (4.1 ± 1.6) and the Follicular Fluids levels vary from a minimum of 7,1 ng/mL to a maximum of 55.3 ng/mL (13.8 ± 10.9).

In the HEI (High Environmental Impact) group, serum levels vary from a minimum of 69.2 ng/mL to a maximum of 167.8 ng/mL (95.5 ± 24.3) and Follicular Fluids levels vary from a minimum of 4.2 ng/mL to a maximum of 34.3 ng/mL (19.9 ± 9.2).

Statistical processing of the data shows a highly significant variation in serum levels (p < 0.0001) with higher values in the HEI group (95.5 ± 24.3) than in the LEI group (4.1 ± 1.6).

A moderately significant change (p < 0.01) for Follicular Fluids levels, higher in the HEI group (19.9 ± 9.2) than in the LEI group (13.8 ± 10.9).

Furthermore, the data did not show any correspondence between serum and Follicular Fluids for any of the participants tested.

Limitations, reasons for caution

The ELISA method for the determination of BPA seems suitable to us, however, the subject requires further biomonitoring studies, with a larger sample and greater selection of participants, to better understand the effects of BPA and its metabolites in FF and in other districts of the female reproductive system.

Wider implications of the findings

The results indicate that the greater bioaccumulation in women of the HEI group appears consistent with the environmental condition of the area and with the comparative studies already carried out within the EcoFoodFertility project. This is further evidence that pollution in this area can interfere with female fertility and beyond.

Trial registration number

G003

P–074 Chromatin Maturity Index (CMI) in unfixed and live spermatozoa and Aniline Blue (AB) stained as an additional evaluation parameter in idiopathic male infertility

Study question

To investigate whether idiopathic male infertility may be due to the presence of histones in motile spermatozoa using a modified AB staining protocol.

Summary answer

No correlation between CMI in live motile spermatozoa, DNA Fragmentation Index (DFI) and other conventional seminal parameters were found in male infertile patients.

What is known already

The AB stain discriminates between lysine-rich histones and arginine/cysteine-rich protamines. Transition from histones to protamines during spermatogenesis remodels chromatin packaging and abnormalities in the substitution of those proteins maybe interfere with seminal parameters and affect male infertility. The correlation between CMI and seminal parameters is known, but little is knowledge about live and motile spermatozoa associated to CMI because literature report only spermatozoa fixation before staining. Sperm chromatin carries half of the genomic material to offspring. Spermatozoa nuclear status is crucial for balanced transmission to future generations, and histones modifications are directly involved in epigenetic mutations.

Study design, size, duration

Retrospective observational study of 77 men underwent to standard semen analysis, including the evaluation of CMI and DFI, enrolled from January to December 2020. Mean age of the men was 36.63±8.26 years old, sperm concentration 46.69±37.23 mill/mL, linear progressive motility 39.35±15.31%, normal morphology 6.42±3.40%, DFI 25.91±10.29%. 200 spermatozoa for evaluation of CMI and 300 for DFI were analyzed respectively.

Participants/materials, setting, methods

Semen samples of 77 patients were collected and analyzed according to 5th edition of WHO guidelines (2010) for examination of human semen. For the evaluation of CMI we performed a new modified protocol for AB stain directly in live spermatozoa. Dilution 1:1 fresh semen and Aniline Blue colorant were mixed and placed on a slide and examined in bright field microscopy x1000 magnification. DFI was evaluated using Sperm Chromatin Dispersion (SCD) test.

Main results and the role of chance

Of all spermatozoa analyzed, 82.58±29.98% were white, 17.17±17.21% were pale blue, and 28.53±21.09% were dark blue. By our modified protocol, directly in live spermatozoa, we correlated AB staining with motility and , surprisingly, all motile spermatozoa observed were not stained (white), while pale or dark blue spermatozoa resulted always immotile. For this reason, we have considered pale blue spermatozoa as AB positive, in disagreement with some authors. So, maybe, we should reconsider pale blue stained spermatozoa as abnormal. We also observed AB negative spermatozoa with morphological head, neck and tail defects, underlining the independence of these two parameters: nuclear status and morphology. We have observed no statistically significant differences between conventional semen parameters, DFI and CMI, so nuclear analysis seems to be independent parameters. The statistical analysis was performed by Matlab statistical toolbox version 2008 (MathWorks, Natick, MA, USA) for Windows at 32 bit; finally all tests with p-value (p) < 0.05 were considered significant. Attention should be paid to the evaluation of CMI not only in astenozoospermic patients, where a lower CMI is known, but also in normozoospermic infertile patients.

Limitations, reasons for caution

This is a preliminary observational study on a small number of normozoospermic or mild asthenozoospermic patients. The study should be considered as a pilot study. Future studies with higher number of samples are necessary in order to confirm the results obtained.

Wider implications of the findings: This is the first study that reports AB staining on unfixed live spermatozoa with a modified protocol. Our study underlines the necessity of classify pale blue spermatozoa as AB positive. Further investigations are necessary. This is a starting point for future analysis to be carried out under the project EcoFoodFertility.

Trial registration number

Not applicable