Study Links Water Pollution With Declining Male Fertility

New research strengthens the link between water pollution and rising male fertility problems. The study, by Brunel University, the Universities of Exeter and Reading and the Centre for Ecology & Hydrology, shows for the first time how a group of testosterone-blocking chemicals is finding its way into UK rivers, affecting wildlife and potentially humans. The research was supported by the Natural Environment Research Council and is now published in the journal Environmental Health Perspectives

The study identified a new group of chemicals that act as 'anti-androgens'. This means that they inhibit the function of the male hormone, testosterone, reducing male fertility. Some of these are contained in medicines, including cancer treatments, pharmaceutical treatments, and pesticides used in agriculture. The research suggests that when they get into the water system, these chemicals may play a pivotal role in causing feminising effects in male fish.

Earlier research by Brunel University and the University of Exeter has shown how female sex hormones (estrogens), and chemicals that mimic estrogens, are leading to 'feminisation' of male fish. Found in some industrial chemicals and the contraceptive pill, they enter rivers via sewage treatment works. This causes reproductive problems by reducing fish breeding capability and in some cases can lead to male fish changing sex.

Other studies have also suggested that there may be a link between this phenomenon and the increase in human male fertility problems caused by testicular dysgenesis syndrome. Until now, this link lacked credence because the list of suspects causing effects in fish was limited to estrogenic chemicals whilst testicular dysgenesis is known to be caused by exposure to a range of anti-androgens.

Lead author on the research paper, Dr Susan Jobling at Brunel University's Institute for the Environment, said: "We have been working intensively in this field for over ten years. The new research findings illustrate the complexities in unravelling chemical causation of adverse health effects in wildlife populations and re-open the possibility of a human - wildlife connection in which effects seen in wild fish and in humans are caused by similar combinations of chemicals. We have identified a new group of chemicals in our study on fish, but do not know where they are coming from. A principal aim of our work is now to identify the source of these pollutants and work with regulators and relevant industry to test the effects of a mixture of these chemicals and the already known environmental estrogens and help protect environmental health."

Senior author, Professor Charles Tyler of the University of Exeter, said: "Our research shows that a much wider range of chemicals than we previously thought is leading to hormone disruption in fish. This means that the pollutants causing these problems are likely to be coming from a wide variety of sources. Our findings also strengthen the argument for the cocktail of chemicals in our water leading to hormone disruption in fish, and contributing to the rise in male reproductive problems. There are likely to be many reasons behind the rise in male fertility problems in humans, but these findings could reveal one, previously unknown, factor."

Bob Burn, Principal Statistician in the Statistical Services Centre at the University of Reading, said: "State-of-the-art statistical hierarchical modelling has allowed us to explore the complex associations between the exposure and potential effects seen in over 1000 fish sampled from 30 rivers in various parts of England."

The research took more than three years to complete and was conducted by the University of Exeter, Brunel University, University of Reading and the Centre for Ecology & Hydrology. Statistical modelling was supported by Beyond the Basics Ltd.

The research team is now focusing on identifying the source of anti-androgenic chemicals, as well as continuing to study their impact on reproductive health in wildlife and humans.

Intracytoplasmic Sperm Injection ( ICSI )

Although cases presenting with mild sperm abnormalities can be successfully treated by "classical" IVF, today intracytoplasmic sperm injection ( ICSI ) offers a new dimension of therapy for all the moderate and more severe forms of male infertility.

Indications for ICSI include:

Men presenting with low sperm concentration, motility and / or morphology (irrespective of the degree of these abnormalities), antisperm antibodies, or with poor scores in the functional bioassays

Cases of partial or total fertilization failure in a previous IVF attempt ( with overt or more subtle sperm deficiencies or even with normal semen analysis )

Men presenting with absence of sperm in the ejaculate ( azoospermia ).

These cases were typically considered irreversible with donor sperm or adoption being considered as the only viable options. These challenging cases include two main types of problems:
-obstructive lesions of the male genital tract ( such as congenital bilateral absence of the vas deferens, inflammatory occlusions, previous vasectomy, and others )
-patients presenting with different degrees of testicular insufficiency ( hypospermatogenesis or poor sperm production of testicular origin ).
The former cases can be successfully treated by new techniques of sperm aspiration from the epididymis or the vas deferens followed by ICSI. In the latter cases, sperm can be obtained from the testes by performing an open testicular biopsy or by needle aspiration, also followed by ICSI.

In all these cases, the possibility of freezing "extra" sperm obtained at the time of the urological intervention ( prior to or at the time of IVF / ICSI ) should always be considered. Frozen - thawed sperm may maintain viability and therefore can be used in future ICSI cycles. Sperm freezing is a mandatory and efficient means of maintaining the reproductive potential of men who will have radical therapies in cases of curable cancer. Our sperm bank is ISO 9001:2000 certified and serves local, out - of - state, and international physicians and patients.

Because of the high incidence of male infertility and the outstanding success of the technique, currently we perform ICSI in 40% of all IVF cases. For this technique, success has to be assessed both in terms of fertilization and pregnancy outcome.

There are probably several thousand babies born worldwide through ICSI. Worldwide registries note that in 97% or more of the times that ICSI results in delivery of normal healthy babies. These numbers are probably very close to the results achieved in standard IVF therapy and probably not far from natural reproduction.

However, we are learning more and more about incidences of chromosomal / genetic problems in the infertile man. New techniques are being developed; statistics quote approximately 10% incidence of genetic or chromosomal abnormalities in men with either severely low sperm counts ( oligospermia ) or lack of sperm in the semen ( azoospermia ). For this reason, and in addition to performing a chromosomal evaluation of the fetus ( baby in the uterus ) in early pregnancy either by chorionic villus sampling or amniocentesis, the Jones Institute recommends a genetic consultation.

Intracytoplasmic sperm injection ( ICSI ) research has focused on the impact of ICSI on the meiotic spindle. The spindle is a "web like" intracellular structure that is crucial for normal chromosome alignment and separation during fertilization. We now use a highly specialized imaging system for ICSI procedures, which allows us to visualize and avoid damaging the meiotic spindle. Extensive research indicates that overall there is no increase in the rate of birth defects or other abnormalities after the ICSI procedure.

However, there is some concern that ICSI could increase the incidence of male infertility in offspring and that it could enhance the occurrence of rare sexual chromosomal abnormalities. In nature, the most viable sperm reaches and fertilizes the egg; however, in ICSI, sperm are manually selected thus bypassing this natural selection process. Clinical data are not yet available to conclusively rule out this possibility. We recommend that men with severe oligospermia or non - obstructive azoospermic undergo a baryotype ( blood chromosomal analysis ) and an examination of presence / absence of microdeletions of a Y - chromosome. Genetic counseling is offered as appropriate.

Male painters and decorators at risk of infertility

A joint study carried out by researchers from Britain and Canada has found that exposure to certain chemicals found in paint can make men infertile.

The researchers from University of Alberta, in Canada and the Universities of Manchester and Sheffield and have linked fertility problems in men to their exposure to certain paint chemicals.

The study of 2,118 men undertaking treatment at 14 fertility clinics in the UK found that 874 were working with organic solvents, particularly glycol ethers.

They say this translates to men working with glycol solvents having a 250 percent chance of losing the ability to produce "healthy" sperms.

In the joint research project, the men were questioned about their lifestyles and occupations in order to establish possible causes of sperm motility problems.

The research revealed that painters, decorators, and those who are regularly exposed on glycol ethers, chemicals commonly used as solvents for water-based paint are two-and-a-half times more prone to fertility problems.

Glycol ether solvents are widely used in many products, including popular water-based emulsions.

A man's ability to father a baby is affected by sperm motility, the amount of movement seen in individual sperm, which serves as a part of measuring male fertility.

The researchers say glycol ether exposure was related to low motile sperm count in men attending fertility clinics and are a hazard for male fertility but other chemicals found in paint had no impact on fertility.

Klinefelter's Syndrome

Klinefelter's Syndrome is a genetic disorder characterized by infertility, abnormal male breast tissue development (gynecomastia) and small, firm testes. It is the most common cause of azoospermia (no sperm production). Klinefelter's Syndrome is caused by an abnormal number of sex chromosomes. Whereas a normal male genetic make-up includes one "X" chromosome and one "Y" chromosome, in patients with Klinefelter's Syndrome, an extra "X" chromosome is present, resulting in three (XXY) sex chromosomes. Thought at one time to be hopelessly infertile, it has been found that these men can have small amounts of sperm production occuring within the testicle. Our Center has successfully recovered sperm in men with this disorder who have gone on to father normal, healthy children. It is important that all men with very low or absent sperm counts be tested for Klinefelter's Syndrome before offering IVF and ICSI.