Is There a Correlation Between Organochlorine Compounds and Undescended Testes?

European Journal of Pediatric Surgery 2000; 10: 304-309

Received: May 12, 2000

S. Hosie¹*, S. Loff¹, K. Witt², K. Niessen², K.-L. Waag^1
1Department of Paediatric Surgery, Mannheim University Hospital, Mannheim, Germany
²Department of Paediatrics, Mannheim University Hospital, Mannheim, Germany

* Contact: Dr. med. Stuart Hosie
Department of Pediatric Surgery Mannheim University Hospital University of Heidelberg Theodor-Kutzer-Ufer 68167 Mannheim Germany
E-mail: stuart.hosie@kch.ma.uni-heidelberg.de 

Summary

Some pesticides and synthetic chemicals are known to act as hormonal modulators, often possessing oestrogenic activity (xenooestrogens). They are persistent and accumulate in fatty tissue. Aim of our study is to address the question, whether a selection of such compounds is to be found in the fatty tissue of children undergoing surgical procedures and whether there are differences in values obtained from patients with or without undescended testes. Fat samples of 48 patients, 18 of whom had undescended testes, were examined by high-resolution gas chromatography and mass spectrometry for DDT and metabolites, polychlorinated biphenyls (PCB), toxaphenes, hexachlorocyclohexane (HCH), chlorinated cyclodienes and chlorinated benzenes. We were able to find accumulation of all substances in every patient. Statistical analysis revealed a highly significant difference between patients from the control group and those from the undescended testes group for two compounds, namely heptachloroepoxide (HCE) and hexachlorobenzene (HCB), increased values being found in the patients with undescended testes. Since the aetiology of this entity is unknown in most of the cases, prenatal exposure to exogenous oestrogens is an attractive and plausible hypothesis. In order to confirm this, some questions will have to be answered in further studies: effect of exposure to xenooestrogens during a specific period of development, probable role of other substances with proven or suspected hormonal activity, potential synergism of such compounds and differences in individual susceptibility.

• Key words: Pesticides - Xenooestrogens - Environmental pollutants - Testicular descent - Cryptorchidism -Undescended testes

Introduction

Pesticides are biologically active substances intentionally dispersed into the environment by man. About 1600 different substances have either been used, or are still employed. There are 15,000 different chlorinated compounds, about 50% of which are persistent and resist natural decay. They are found in all ecological spaces, even far distant from industrial or agricultural regions. Due to their extreme lipophilia they accumulate in fatty tissue and can be found in high concentrations, as one moves up the food chain (19).

At least 51 chemical substances have been identified as endocrinal modulators, possessing the capacity to alter hormonal activity (24). Some of them, known as xenooestrogens, act as oestrogen receptor agonists. Other compounds, such as toxaphens, are antioestrogens, or androgen receptor antagonists, as the DDT metabolite p,p'-DDE (15). Such substances have been made responsible for altering social behaviour, causing birth defects and adverse effects on fertility in different animal species (6,8,12). In humans they have been accused of causing learning disability, adverse effects on the immune system and thyroid function, endometriosis, breast and prostate cancers, abortions, stillbirths, intrauterine growth retardation and disorders of the male reproductive tract such as declining sperm counts, testicular cancer, hypospadias and undescended testes (7,9,13,22).

Aim of our study is to address the question whether a selection of such compounds is to be found in the fatty tissue of children undergoing surgical procedures in our Department, and whether there are differences in values obtained from patients with or without undescended testes.

Patients and Methods

Fat samples of 48 patients were obtained during a surgical procedure, 18 patients underwent an orchidopexy due to Unilateral (8 patients) or bilateral (10 patients) undescended testis. Population characteristics are listed in Table 1.

Table 1 Characteristics of the population studied

Each tissue sample was stored in an aluminium container at -20°C until processing. 26 different organochlorine compounds were determined in each tissue sample (Tables 2,3) as follows:

The fatty tissue was macerated and lipids separated from tissue, blood and water residues by means of Soxhlet extraction. The lipid quantity was determined gravimetrically ally ( 1, 2). To allow for an exact determination of traces of or organochlorinated compounds, an internal standard (isotope-marked 113C12 99%] PCB mixture [Nrs. 28, 52,101,138, 153,180, 209], [Promochem, Wesel, Germany]) was added. To be able to measure substances contained in minimal quantities (PPM, PPB) a clean-up was performed by means of column chromatography as described by Storr-Hansen and Cederberg (25). With this procedure the lipids are destroyed keeping the organochlorines intact which are eluted with n-hexane. The obtained solution was examined by high-resolution gas chromatography and mass spectrometry. Determination of polychlorinated biphenyls (PCB) was performed using the electron impact ionisation modus; for the remaining substances, negative chemical ionisation was employed. Identification of the substances was possible by comparison with standardised solutions (Ehrenstorfer, Augsburg, Germany; Promochem, Wesel, Germany). Quantification was performed using the internal standard, all values are expressed in µgr/kg fat (1).

For each single substance, the values obtained from patients with descended testes were compared with those from patients with undescended testes. Statistical differences were determined using the two-tailed Mann-Whitney-Wilcoxon test and was considered significant for p < 0.05.

Table 2 Classification of the compounds determined in each sample

Table 3 Main features of the groups of substances deter mined

Results

We were able to find accumulation of all substances in every patient. Plotting of the obtained values for each compound showed a high variance and a non-normal distribution. The calculated medians and ranges for patients from the control group (normal-positioned gonads) and the Undescended testes group are shown in Tables 4 to 8.

Statistical analysis revealed a highly significant difference between patients from the control group and those from the undescended testes group for two compounds, namely heptachloroepoxide (HCE) and hexachlorobenzene (HCB), with increased values found in the patients with undescended testes (p=0.009 and 0.012, respectively). Medians and ranges for these substances are displayed graphically in Figs. l and 2.

Table 4 Medians and ranges of values of DDT and metabolites in patients from the control group (contr.) and the undescended testes group (und.). All values expressed in µgr/kg fat

Table 5 Medians and ranges of values of polychlorinated biphenyls (PCB) in patients from the control group (contr.) and the undescended testes group (und.). All values expressed in µgr/kg fat

Table 6 Medians and ranges of values of toxaphene and hexachlorohexane (HCH) in patients from the control group (contr.) and the undescended testes group (und.). All values expressed in µgr/kg fat

Table 7 Medians and ranges of values of chlorinated cyclodienes in patients from the control group (contr.) and the undescended testes group (und.). All values expressed in µgr/kg fat

Table 8 Medians and ranges of values of chlorinated benzenes in patients from the control group (contr.) and the undescended testes group (und.). All values expressed in µgr/kg fat

Discussion

Epidemiological data suggest an increase of disorders of the male reproductive tract in the last decades (10), including declining sperm counts, testicular cancer, hypospadias and undescended testes (3,16). Clinical and experimental studies have shown that exposure to excess of oestrogens may cause such disorders (5,9,14,21). The proposed mechanism is a down-regulation of FSH by the foetal pituitary, leading to a decline in the number of Sertoli cells and diminished secretion of Müllerian inhibiting substance. Additionally, oestrogens inhibit Leydig cell development, compromising endogenous testosterone production (76,23).

Kennedy and Snyder summarised the potential routes of increased human exposure to exogenous oestrogens (16): increased reabsorption of endogenous and exogenous oestrogens due to low-fibre diet: increased exposure to phytooestrogens such as those contained in soya beans; increased consumption of oestrogen-containing diary products; synthetic oestrogens in form of oral contraceptives, which find their way back into drinking water during water recycling; finally, exposure to a vast group of environmental pollutants known to have oestrogenic effects. The last-named compounds have special features: they resist natural decay and their lipophilia causes accumulation in fatty tissue. Their bioaccumulation rises the higher one climbs tip in the food chain. Although many substances are prohibited in industrialised countries, some are still in use in countries of the Third World. Other substances suspected of possessing oestrogenic activity are still widely in use (4, 6, 11).

	Fig. l HCB values obtained in patients from the control and undescended testes groups. The lowest and the highest value represent the range, the value in-between shows the median.
	Fig.2 HCE values obtained in patients from the control and Undescended testes groups. The lowest and the highest value represent the range, the value in-between shows the median

The oestrogenic effect of these xenobiotics is rather weak as compared to naturally occurring hormones. As opposed to the latter, they do not bind to serum proteins, increasing their bioavailability. Another fact of capital importance is the special susceptibility of developing organisms to even low concentrations of hormonally active substances. Children are exposed to high levels not only in utero, but during lactation as well (17,18,26).

To our knowledge there are no data available regarding accumulation of chlorinated compounds in patients with undescended testes as compared to a control population with descended gonads. We were able to find in each patient varying quantities of all 26 substances determined, confirming their ubiquitous distribution and accumulation. The wide distribution of values reflects the interindividual differences caused by geographic provenience and alimentary habits. Nevertheless, we were able to find a highly significant difference in bioaccumulation of two compounds: HCE and HCB, with higher values in patients with undescended testes. Since the aetiology of this entity is unknown in most of the cases, prenatal exposure to exogenous oestrogens is an attractive and plausible hypothesis. However, our findings do not prove a direct causality between accumulation of these compounds and undescended testes since they reflect the total accumulation until the time of sampling. They do not allow any conclusion regarding exposure during a specific period of development. As we Know, the timing of an event is determinant in the genesis of a malformation. Some additional issues will have to be addressed as well, such as the probable role of many other substances with proven or suspected hormonal activity, a potential synergism in bioactivity of such compounds and probable differences of individual susceptibility. Additional efforts should be undertaken to find answers to these open questions.

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