Supervisors info:
Αναστασία Κωνσταντινίδου,Καθηγήτρια, Ιατρική Σχολή ΕΚΠΑ Επιβλέπουσα
Νικόλαος Καβαντζάς, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Ανδρέας Χ. Λάζαρης, Καθηγητής, Ιατρική Σχολή, ΕΚΠΑ
Summary:
There are thousands of chemicals in the environment, generally thought to be potentially dangerous, so that people try to defend their lives, ignoring that the existence of life itself is characterized by chemical substances. It is considered that human safety depends on the degree of exposure and the kind of chemical. Although some of the chemical substances are harmful and toxic to humans, also affecting reproduction, there are widespread throughout our environment and human exposure is unavoidable.
Due to modern living and working conditions, some chemical components constitute a serious threat to human reproduction, causing harmful effects that disturb endocrine and reproductive functions by affecting the human body, especially cells, and producing damage in reproductive health, in the female cellular genetic material, in the sexual function and fertility. Unfortunately those compounds are ubiquitous in the environment and are often difficult to avoid.
Endocrine disrupting chemicals (EDC’s) are synthetic chemicals or mixture of chemicals that alter the hormonal and homoeostatic systems of organisms, resulting in adverse health effects. EDC’s include persistent pollutants, agrochemicals, and widespread industrial compounds. Not at all EDC’s are man-made compounds, many plants produce substances (phytoestrogens) that can have different endocrine effects, considered beneficial in certain circumstances. It has been shown however that exposure to EDC’s may result in a wide range of adverse reproductive effects due to their ability to interfere with aspects of hormonal action. An initial study in 1938 had revealed that some chemicals mimic the effects of estrogen.
In general, chemical components used in plastics are detected in the human organism and in the environment, raising concern due to their potential to interfere with the physiology of living organisms. EDC’s have the ability to modulate the endocrine system by altering the metabolism or synthesis of endogenous hormones, eventually influencing recruitment of transcription factors and altering gene expression in cells. Some chemicals components which are used in consumer products in our household include: Phthalates (PVC). Experimental studies in animals suggest that PVC adversely affect female fecundity, yet whether these same adverse effects are observed in humans remains to be determined. They are found in soft plastic products (softening brittle polyvinyl chloride). Alkyl phenols ethoxalate found in cleaning products, pesticides, plastics, water-based paints and cosmetics. Bisphenol A in epoxy coatings, in plastics bottles and breastplates. Tributyltin (TBT), which is used as a fungicide and algaecide. Exposure to pesticides may reduce female fertility, but also increase the risk of congenital disorders, miscarriages or fetal death.
Effects on woman reproduction is often the result of exposure during close vulnerable periods, such as ovulation. These effects may arise from their action in several stages beginning in fetal life, during development and reproductive period. There is evidence that long term exposure to chemicals which act as endocrine disruptors may affect female fecundity. Particularly they appear to have a role in causing pathological endometriosis and ovarian pathology. In addition, timing, duration and intensity of exposure are important in assessing reproductive adverse effects.
Reproductive disorders are serious health problems and recent research indicates that human infertility rate is increasing. Environmental contaminants are important causal agents for the growing infertility rate, although various reasons have been hypothesized for this change. WHO has recognized infertility as a worldwide public health issue.The reported international prevalence of infertility ranges from 4% to 14% in different countries and regions.
In conclusion, evidence supporting an association between chemicals and EDC’s concentration and ovarian reserve in women remains limited. Future studies are needed to better understand the effects of chemicals, including the need to examine the combined effects of multiple chemicals and to study different mechanisms of action.
Keywords:
Chemicals, Fecundity, Phthalates, PCB's, Glycol ethers
