Environmental Impacts on Male Reproductive Development: Lessons from Experimental Models.

BACKGROUND: Male reproductive development in mammals can be divided into a gonadal formation phase followed by a hormone-driven differentiation phase. Failure of these processes may result in Differences in Sex Development (DSD), which may include abnormalities of the male reproductive tract, including cryptorchidism, hypospadias, infertility, and testicular germ cell cancer (TGCC). These disorders are also considered to be part of a testicular dysgenesis syndrome (TDS) in males. Whilst DSDs are considered to result primarily from genetic abnormalities, the development of TDS disorders is frequently associated with environmental factors. SUMMARY: In this review, we will discuss the development of the male reproductive system in relation to DSD and TDS. We will also describe the experimental systems, including studies involving animals and human tissues or cells that can be used to investigate the role of environmental factors in inducing male reproductive disorders. We will discuss recent studies investigating the impact of environmental chemicals (e.g., phthalates and bisphenols), lifestyle factors (e.g., smoking) and pharmaceuticals (e.g., analgesics) on foetal testis development. Finally, we will describe the evidence, involving experimental and epidemiologic approaches, for a role of environmental factors in the development of specific male reproductive disorders, including cryptorchidism, hypospadias, and TGCC. KEY MESSAGES: Environmental exposures can impact the development and function of the male reproductive system in humans. Epidemiology studies and experimental approaches using human tissues are important to translate findings from animal studies and account for species differences in response to environmental exposures.

Breast Cancer and Major Deviations of Genetic and Gender-related Structures and Function.

We have searched the literature for information on the risk of breast cancer (BC) in relation to gender, breast development, and gonadal function in the following 8 populations: 1) females with the Turner syndrome (45, XO); 2) females and males with congenital hypogonadotropic hypogonadism and the Kallmann syndrome; 3) pure gonadal dysgenesis (PGD) in genotypic and phenotypic females and genotypic males (Swyer syndrome); 4) males with the Klinefelter syndrome (47, XXY); 5) male-to-female transgender individuals; 6) female-to-male transgender individuals; 7) genotypic males, but phenotypic females with the complete androgen insensitivity syndrome, and 8) females with Mayer-Rokitansky-Küster-Hauser (MRKH) syndrome (müllerian agenesis). Based on this search, we have drawn 3 major conclusions. First, the presence of a Y chromosome protects against the development of BC, even when female-size breasts and female-level estrogens are present. Second, without menstrual cycles, BC hardly occurs with an incidence comparable to males. There is a strong correlation between the lifetime number of menstrual cycles and the risk of BC. In our populations the BC risk in genetic females not exposed to progesterone (P4) is very low and comparable to males. Third, BC has been reported only once in genetic females with MRKH syndrome who have normal breasts and ovulating ovaries with normal levels of estrogens and P4. We hypothesize that the oncogenic glycoprotein WNT family member 4 is the link between the genetic cause of MRKH and the absence of BC women with MRKH syndrome.

Prevalence of Mental Illness in Adolescents and Adults With Congenital Heart Disease from the Colorado Congenital Heart Defect Surveillance System.

The aim of this study was to estimate the prevalence of the full spectrum of mental illness in adolescents (aged 11 to 17) and adults (aged 18 to 64) with congenital heart defects (CHDs) in the population-level Colorado Congenital Heart Disease Surveillance System. Further we sought to investigate whether severity of the defect, frequency of recent cardiac procedures or underlying genetic disorders influence these estimates. The cohort included patients in clinical care for CHDs between January 1, 2011 and December 31, 2013, identified across multiple healthcare systems and insurance claims. Of 2,192 adolescents with CHDs, 20% were diagnosed with a mental illness with the most prevalent categories being developmental disorders (8%), anxiety disorders (6%), attention, conduct, behavior, impulse control disorders (6%), and mood disorders (5%). Of 6,924 adults with CHDs, 33% were diagnosed with a mental illness with the most prevalent categories being mood disorders (13%), anxiety disorders (13%), and substance-related disorders (6%). Greater lesion complexity was associated with a higher likelihood of anxiety and developmental disorders in both adolescents and adults. Adolescents and adults who had ≥2 cardiac procedures in the 3-year surveillance period had a 3- and 4.5-fold higher likelihood of a mental illness diagnosis, respectively, compared with those who had fewer than 2 cardiac procedures. Finally, patients with a genetic syndrome were more likely to have a mental illness diagnosis. In conclusion, mental illness is a prevalent co-morbidity in the adolescent and adult population with CHDs, thus comprehensive care should include mental health care.

Etiology and management of primary amenorrhoea: A study of 102 cases at tertiary centre.

OBJECTIVE: To determine the prevalence of etiologic causes of primary amenorrhea in Indian population. MATERIALS AND METHODS: A retrospective study was performed using 102 complete medical records of women with primary amenorrhea who attended the Gynaecologic Endocrinology Clinic, Department of Obstetrics and Gynaecology, AIIMS, New Delhi from September 2012 to September 2015. Cases were analysed according to clinical profile, development of secondary sexual characteristics, physical examination, pelvic and rectal examination, X-ray of chest and lumbo-sacral spine, hormone profile, pelvic USG, MRI, and cytogenetic study including karyotype. RESULTS: The three most common causes of primary amenorrhea were Mullerian anomalies (47%), gonadal dysgenesis (20.5%), and hypogonadotropic hypogonadism (14.7%) in the present study. There were 3 cases of Turner syndrome (45,XO), 5 cases of Swyer's syndrome (46,XY) and 2 cases of Androgen insensitivity syndrome (46,XY). One case had pituitary macroadenoma and eight cases (7.8%) were of genital tuberculosis. CONCLUSIONS: The present study has currently been the largest case series of primary amenorrhea from North India. Mullerian anomaly is the most prevalent etiological factor leading to amenorrhoea followed by gonadal dysgenesis in our study. Racial, genetic and environmental factors could play role in the cause of primary amenorrhea.

Is a CIS phenotype apparent in children with Disorders of Sex Development? Milder testicular dysgenesis is associated with a higher risk of malignancy.

All malignant testicular germ cell tumors (TGCT) of adult men are preceded by an in situ stage (CIS) of protracted evolution. The adult CIS is well characterized, but there is debate on the phenotype of infantile CIS, its distinction from delayed maturation of germ cells and prognostic potential. A large series of 43 patients with Disorders of Sex Development (DSD) and dysgenetic testes (90% ranging from neonates to 12 years, mean age 4.7 years), was studied by quantifying dysgenetic features, degree of germ cell abnormalities/atypia (GCA), expression of OCT 3/4 (a pluripotency-undifferentiation marker), germ cell ploidy and evolution to CIS and invasive TGCT. Findings were compared with those of normal testes. The type of gonads present defined three groups of patients: bilateral testes (BT-DSD, n = 21), one testis and one streak gonad (CT-DSD, C for combined, n = 13), and ovarian-testicular combinations (OT-DSD, n = 9). There were 5 boys with infantile CIS, bilateral in 3 (total of 8 infantile CIS) and two patients with adult CIS, bilateral in one (total of 3 adult CIS). Two patients had bilateral seminomas one at 12-17 and the other at 23 years. Histological dysgenesis was significantly higher in CT-DSD (p < 0.05), that had only 1 CIS. The highest frequency of GCA was in BT-DSD (p < 0.05), which coincided with a total of 11CIS + Seminomas. In all patients, aneuploidy was significantly higher (63%) than diploidy (p < 0.02), and GCA were more frequent in aneuploid than in diploid samples (p < 0.02). All CIS and TGCT were OCT 3/4 positive. Finally, there was a significant association between the triad Aneuploidy + GCA + OCT 3/4 positivity and the incidence of CIS (Fisher Exact test p < 0.002, relative risk 7.0). The degree of testicular dysgenesis (derived from abnormal organization of Sertoli cells in fetal testicular cords) is inversely related to the incidence of CIS. Our data demonstrate that the combined use of OCT 3/4 expression, quantification of germ cell abnormalities-atypia and ploidy in dysgenetic testes can satisfactorily identify infantile CIS with high risk of malignant evolution and set it aside from delayed germ cell maturation with lower or nil neoplastic potential.

Regional differences and temporal trends in male reproductive health disorders: semen quality may be a sensitive marker of environmental exposures.

The decline in semen quality has been the subject of an animated debate. A recent prospective study now irrefutably shows a decline in semen quality in men from Finland, a country that previously boasted good semen quality. Semen quality has, in some countries, reached a level where a considerable fraction of young men are at risk of fertility problems. Impaired semen quality, testicular cancer, cryptorchidism and hypospadias are risk factors for each other, and the testicular dysgenesis syndrome (TDS) has been put forward to explain the observations. This syndrome implies that the four disease entities share the same patho-physiological etiology caused by disturbed testicular development in early fetal life. It seems likely that the rapid rise in TDS-associated conditions can, at least partly, be explained by environmental factors. Animal studies provide strong evidence that manmade chemicals can disrupt the hormone dependent pathways responsible for fetal gonadal development, subsequently leading to TDS-like symptoms. In humans, fetal exposure to endocrine disrupting substances may play a role, although genetic factors are probably also involved. Recent studies indicate that exposure to endocrine disrupters also in adulthood may affect semen quality and reproductive hormones. Causal relationships are inherently difficult to establish in humans, and a clear connection between the disorders and specific toxicants has not been established. It seems likely that the cumulative effects of various low-dose exposures to endocrine disrupters in our environment are responsible for the adverse effects in the male reproductive system. Semen quality may be the most sensitive marker of adverse environmental exposures, and we suggest that standardized surveillance studies of semen quality are continued or initiated to monitor the combined effects of various preventive actions.

Causes of primary amenorrhea: a report of 295 cases in Thailand.

AIMS: The aim of this study was to determine the prevalence of etiologic causes of primary amenorrhea in Thailand. METHODS: A retrospective study was performed using 295 complete medical records of women with primary amenorrhea who attended the Gynecologic Endocrinology Clinic, Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Thailand from September 1992 to February 2009. RESULTS: The three most common causes of primary amenorrhea were Müllerian agenesis (39.7%), gonadal dysgenesis (35.3%), and hypogonadotropic hypogonadism (9.2%). Amongst 88 cases of gonadal dysgenesis, 59 cases (67.0%) incurred abnormal karyotype including 45X (n=21), mosaic (n=31), and others (n=7). CONCLUSIONS: The present study has currently been the largest case series of primary amenorrhea. Müllerian agenesis is the most prevalent cause in our study, while gonadal dysgenesis is the most common cause in the largest-scale study in the USA. Hence, racial, genetic and environmental factors could play roles in the cause of primary amenorrhea.

Complete gonadal dysgenesis in clinical practice: the 46,XY karyotype accounts for more than one third of cases.

OBJECTIVE: To determine the frequency of XY karyotypes among females with complete gonadal dysgenesis (CGD) and to investigate the frequency of both gonadal tumors and SRY mutations. DESIGN: Retrospective study based on data from all patients with CGD seen in our service from 1989 to 2010. SETTING: Clinic for disorders of sex development, University Hospital, State University of Campinas. PATIENT(S): Thirty-two patients with hypergonadotropic hypogonadism, streak gonads, internal and external female genitalia, and normal karyotype (46,XX or 46,XY); 31 were index cases and 29 did not have a previously determined karyotype. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): None. RESULT(S): The percentage of XY karyotypes among patients with CGD was 34.5% (10/29). Mean age at diagnosis among XY and XX patients was 17.4 years and 19.9 years, respectively. Gonadal tumors were found in 4 of 9 XY girls, and 7 of 10 had SRY gene mutations. CONCLUSION(S): The previously unreported finding of an elevated frequency of 46,XY karyotype among patients with CGD and the high risk of gonadal neoplasia in such cases indicate that this diagnosis must be kept in mind by clinicians and strengthen the importance of karyotype analysis in females with primary hypogonadism. In addition, the frequency of SRY mutations in XY CGD might be higher than previously considered.

Organochlorine compounds and testicular dysgenesis syndrome: human data.

Cryptorchidism, hypospadias, subfertility and testicular germ-cell tumour have been suggested to comprise a testicular dysgenesis syndrome (TDS) based on the premise that each may derive from perturbations of embryonal programming and gonadal development during foetal life. Endocrine-disrupting chemicals have been hypothesized to be associated with these disorders, given the importance of sex steroid hormones in urogenital development and homeostasis. Organochlorines are one such set of compounds which are defined as containing between one and ten covalently bonded chlorine atoms. These compounds are persistent pollutants with long half-lives, accumulate in adipose tissue when ingested, bioaccumulate and biomagnify, and have complex and variable toxicological profiles. Examples of organochlorines include dichloro-diphenyl-trichloroethane and its metabolites, polychlorinated biphenyls, and chlordane. In this comprehensive review of human epidemiologic studies which have tested for associations between organochlorines and facets of TDS, we find evidence for associations between the exposures p,p'-DDE, cis-nonachlor and trans-nonachlor with testicular germ-cell tumour. The sum of the evidence from human epidemiological studies does not indicate any association between specific organochlorines studied and cryptorchidism, hypospadias or fertility. Many other endocrine-disrupting chemicals, including additional organochlorines, have yet to be assessed in relation to disorders associated with TDS, yet study of such chemicals has strong scientific merit given the relevance of such hypotheses to urogenital development.

Recent adverse trends in semen quality and testis cancer incidence among Finnish men.

Impaired semen quality and testicular cancer may be linked through a testicular dysgenesis syndrome of foetal origin. The incidence of testis cancer has been shown to increase among Finnish men, whereas there is no recent publication describing temporal trends in semen quality. Therefore, we carried out a prospective semen quality study and a registry study of testis cancer incidence among Finnish men to explore recent trends. A total of 858 men were investigated in the semen quality study during 1998-2006. Median sperm concentrations were 67 (95% CI 57-80) million/mL, 60 (51-71) and 48 (39-60) for birth cohorts 1979-81, 1982-83 and 1987; total sperm counts 227 (189-272) million, 202 (170-240) and 165 (132-207); total number of morphologically normal spermatozoa 18 (14-23) million, 15 (12-19) and 11 (8-15). Men aged 10-59 years at the time of diagnosis with testicular cancer during 1954-2008 were included in the registry study, which confirmed the increasing incidence of testicular cancer in recent cohorts. These simultaneous and rapidly occurring adverse trends suggest that the underlying causes are environmental and, as such, preventable. Our findings necessitate not only further surveillance of male reproductive health but also research to detect and remove the underlying factors.

What is new in cryptorchidism and hypospadias--a critical review on the testicular dysgenesis hypothesis.

It has been hypothesized that poor semen quality, testis cancer, undescended testis, and hypospadias are symptoms of one underlying entity--the testicular dysgenesis syndrome--leading to increasing male fertility impairment. Though testicular cancer has increased in many Western countries during the past 40 years, hypospadias rates have not changed with certainty over the same period. Also, recent studies demonstrate that sperm output may have declined in certain areas of Europe but is probably not declining across the globe as indicated by American studies. However, at the same time, there is increasing recognition of male infertility related to obesity and smoking. There is no certain evidence that the rates of undescended testes have been increasing with time during the last 50 years. In more than 95% of the cases, hypospadias is not associated with cryptorchidism, suggesting major differences in pathogenesis. Placental abnormality may occasionally cause both cryptorchidism and hypospadias, as it is also the case in many other congenital malformations. The findings of early orchidopexy lowering the risk of both infertility and testicular cancer suggest that the abnormal location exposes the cryptorchid testis to infertility and malignant transformation, rather than there being a primary abnormality. Statistically, 5% of testicular cancers only are caused by cryptorchidism. These data point to the complexity of pathogenic and epidemiologic features of each component and the difficulties in ascribing them to a single unifying process, such as testicular dysgenesis syndrome, particularly when so little is known of the actual mechanisms of disease.

Cryptorchidism as part of the testicular dysgenesis syndrome: the environmental connection.

Cryptorchidism is part of the testicular dysgenesis syndrome (TDS), which includes other male reproductive disorders such as hypospadias, testis cancer and reduced semen quality. These diseases appear to be linked by common pathogenic mechanisms, interfering with normal fetal testis development. Testis development and descent is dependent on androgens and thus on an intact hypothalamus-pituitary-gonadal axis. Although cryptorchidism occurs in rare syndromes and genetic disorders, in the majority of children the etiology remains open. Many maternal and fetal risk factors have been previously identified but recently, scientific focus has also been directed to environmental hormone disrupting chemicals and lifestyle, as the prevalence of testis cancer and cryptorchidism has increased and semen quality decreased over few decades in several countries. Some persistent environmental chemicals, e.g. polychlorinated pesticides and polybrominated flame retardants, were associated with testicular maldescent and testis cancer. In addition, prenatal exposure to phthalates was negatively correlated to testosterone levels and anogenital distance as a measure of androgen effect in infant boys. Alcohol consumption and maternal smoking during pregnancy also appeared to be a risk factor for cryptorchidism. Thus, current evidence suggests that the development of the male reproductive tract may be susceptible to adverse effects of environmental hormone disrupters.

Trichothiodystrophy: a systematic review of 112 published cases characterises a wide spectrum of clinical manifestations.

Trichothiodystrophy (TTD) is a rare, autosomal recessive disease, characterised by brittle, sulfur deficient hair and multisystem abnormalities. A systematic literature review identified 112 patients ranging from 12 weeks to 47 years of age (median 6 years). In addition to hair abnormalities, common features reported were developmental delay/intellectual impairment (86%), short stature (73%), ichthyosis (65%), abnormal characteristics at birth (55%), ocular abnormalities (51%), infections (46%), photosensitivity (42%), maternal pregnancy complications (28%) and defective DNA repair (37%). There was high mortality, with 19 deaths under the age of 10 years (13 infection related), which is 20-fold higher compared to the US population. The spectrum of clinical features varied from mild disease with only hair involvement to severe disease with profound developmental defects, recurrent infections and a high mortality at a young age. Abnormal characteristics at birth and pregnancy complications, unrecognised but common features of TTD, suggest a role for DNA repair genes in normal fetal development.

[The concept of endocrine disruption and human health]. / Le concept de perturbation endocrinienne et la santé humaine.

In Europe, endocrine disruptors (EDs) have been defined as substances foreign to the body that have deleterious effects on the individuals or their descendants, due to changes in endocrine function. In the United States, EDs have been described as exogenous agents that interfere with the production, release, transport, metabolism, binding, action or elimination of the natural ligands responsible for maintaining homeostasis and regulating body development. These two definitions are complementary, but both indicate that the effects induced by EDs probably involve mechanisms relating in some way to hormonal homeostasis and action. EDs are generally described as substances with anti-oestrogenic, oestrogenic, anti-androgenic or androgenic effects. More recently, other targets have been evidenced such as the thyroid and immune system. Many different EDs are present in the various compartments of the environment (air, water and land) and in foods (of plant and animal origin). They may originate from food packaging, combustion products, plant health treatments, detergents and the chemical industry in general. In addition to the potential effects of these compounds on adults, the sensitivity of embryos and fetuses to many of the xenobiotic compounds likely to cross the placenta has raised considerable concern and led to major research efforts. With the exception of the clearly established links between diethylstilbestrol, reproductive health abnormalities and cancers, very little is known for certain about the effects of EDs on human health. Given the lack of available data, current concerns about the possible involvement of EDs in the increase in the incidence of breast cancer, and possibly of endometriosis and early puberty in girls, remain hypothetical. Conversely, the deterioration in male reproductive health is at the heart of preoccupations and progress in analyses of the relationship between EDs and human health. This literature review aims to describe the current state of knowledge about endocrine disruption, focusing in particular on the problem of food contaminants.

[Increased risk of testicular dysgenesis?]. / Økt forekomst av utviklingsfeil i testiklene?

The latest figures from the Cancer Registry of Norway show that Norway has the highest incidence rate of testicular cancer in the world. They also show that the incidence rate continues to increase, as it has for the last decades in the western world. The reasons for this increase, which might also be true for urogenital abnormalities in men and reduced sperm quality, are uncertain. Data suggest, however, that these anomalies originate in foetal life, and that contributing factors are genetic, pregnancy-related and environmental. The potential importance of environmental factors must be taken seriously, and the authorities must take action to strengthen the research in this area.

Is human fecundity declining?

Summary The decreasing trends in fertility rates in many industrialized countries are now so dramatic that they deserve much more scientific attention. Although social and behavioural factors undoubtedly play a major role for these trends, it seems premature, and not based on solid information, to conclude that these trends can be ascribed to social and behavioural changes alone. There is evidence to suspect that changing lifestyle and increasing environmental exposures, e.g. to endocrine disrupters, are behind the trends in occurrence of male reproductive health problems, including testis cancer, undescended testis and poor semen quality. These biological factors may also contribute to the extremely low fertility rates. However, the necessary research is complex and requires non-traditional collaboration between demographers, epidemiologists, clinicians, biologists, wild life researchers, geneticists and molecular biologists. This research effort can hardly be carried out without major support from governments and granting agencies making it possible to fund collaborative projects within novel research networks of scientists.

Ethnic differences in occurrence of TDS-- genetics and/or environment?

It has been hypothesized that poor semen quality, testis cancer, undescended testis and hypospadias are symptoms of one underlying entity, the so-called testicular dysgenesis syndrome (TDS). TDS was suggested to be a result of disruption of embryonal programming and gonadal development during foetal life and as aetiological factor, an impact of adverse environmental factors such as hormone disrupters, probably acting upon a susceptible genetic background, was suggested. Extensive studies considering the risk of TDS-related diseases in Denmark compared with Finland, showed higher sperm counts and lower risk of cryptorchidism and testicular cancer among Finns. However, when comparing these two populations, the question arises, to which degree this difference might be due to discrepancy in genetic background. A more obvious example of the impact of genetic factors on the risk of TDS concerns Afro-Americans having significantly lower incidence of testicular cancer when compared with Caucasians living in the USA. A yet unexplored scenario is a possible interaction between genetic and environmental/lifestyle-related factors, certain genotypes making individuals more susceptible to adverse exogenous exposures. Studying such interactions has biological, epidemiological and public health-related implications. It will help us to understand the background for the defects in male reproductive organs, facilitate proper design of epidemiological studies and add to identifying individuals susceptible to certain environmental and lifestyle-related hazards. Such 'susceptibility genes' need to be identified, those involved in the synthesis, action and metabolism of sex steroids being strong candidates.

Cytogenetics and etiology of ambiguous genitalia in 120 pediatric patients.

BACKGROUND: A newborn with ambiguous genitalia needs prompt evaluation to detect life-threatening conditions (e.g., salt-losing crisis in congenital adrenal hyperplasia [CAH]) and gender assignment. Sex assignment in these children continues to be a challenging diagnostic and therapeutic problem. We studied the causes and characteristics of ambiguous genitalia in children who were referred to a cytogenetic laboratory. PATIENTS AND METHODS: We retrospectively reviewed a total of 120 medical records of patients with a primary indication of ambiguous genitalia that were referred to the cytogenetic lab for karyotyping during the period of 1989 to 1999. Diagnosis was based on a clinical impression from the primary physician, who was primarily a staff pediatrician, endocrinologist and/or pediatric urologist. RESULTS: CAH was the underlying cause of ambiguous genitalia in 41 of 63 patients with ambiguity due to endocrine causes; 39 of these patients showed a 46,XX karyotype and 2 cases were 46,XY (both the 46,XY patients had 3 beta-hydroxylase deficiency). In 57 patients, ambiguous genitalia were due to congenital developmental defects. The most common endocrine case of ambiguous genitalia was 21-OH deficiency. Seven patients were classified as idiopathic with six showing the 46,XY and one the 46,XX karyotype. Gender was reassigned at birth or at diagnosis in 15 patients. CONCLUSION: The etiology of ambiguous genitalia is variable. The physician managing these families could minimize the trauma of having a child with unidentified sex by providing appropriate genetic counseling so that the parents can make an early decision. Prenatal DNA testing in at-risk families should be considered and appropriate therapy offered to minimize or prevent genital ambiguity.