Cryptorchidism is the commonest malady to affect newborn male infants. Until recently, the molecular aetiology of this syndrome was unclear. Cryptorchidism may be part of a broader testicular dysgenesis syndrome, wherein a disturbance in steroid hormone metabolism, possibly through a perturbed hypothalamic-pituitary-gonadal axis could be involved. Disturbance may be genetic, or extrinsic through endocrine disruptors. Recently, the role of insulin-like factor-3 (INSL3; alternatively called relaxin-like factor) has been highlighted through the cryptorchid phenotype of mice where genes for either INSL3 or its receptor have been ablated. INSL3 is produced by Leydig cells of the fetal testis and acts upon the gubernacular ligament to retain the gonad in the inguinal region, from which it later passes into the scrotum. INSL3 expression in fetal testis is inhibited by maternal exposure to estrogens. Although to date no mutations have been found in the human INSL3 gene responsible for cryptorchidism, one causative mutation in the INSL3 receptor (LGR8 or GREAT) has been reported. Studies on developmental transcription factors, such as Hoxa-10 in mice, suggest that other specific molecular cascades could also lead to a cryptorchid phenotype. Considering its frequency in newborn children, and the severity of the untreated condition (infertility and often testicular cancer) these new findings should generate new information on possible causes and treatments. (+info)
Management of cryptorchism and risk of testicular cancer.
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Cryptorchism is an established risk factor for testicular cancer, but the role of age at surgical correction is unclear. The authors investigated this relation using information obtained from comprehensive medical records dating to childhood. They conducted a case-control study of 183 Kaiser Permanente members, who were diagnosed with testicular cancer during 1973-1996 and who were 15 years or younger when they first joined the health plan, and 551 controls. Notes pertaining to the testes were reviewed up to the case's diagnosis date or comparable date among the controls. The odds ratio for the association of a history of cryptorchism with testicular cancer risk was 4.8 (95% confidence interval (CI): 1.9, 11.8). Compared with no history of cryptorchism, men with a history who had natural descent or successful orchiopexy by the 11th birthday were not at increased risk of testicular cancer (odds ratio = 0.6, 95% CI: 0.08, 5.4). However, successful treatment of cryptorchism only after the 11th birthday, or never, was related to a 32-fold increased risk (95% CI: 4, 250). Orchiopexy was performed before the 11th birthday on three men who developed testicular cancer but, in each, the procedure failed. In contrast, all four of the early orchiopexies performed on the controls were successful. Boys with failed orchiopexy should be considered for reoperative orchiopexy or orchiectomy to prevent testicular cancer. (+info)
Spermatogonial stem cells share some, but not all, phenotypic and functional characteristics with other stem cells.
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Spermatogonial stem cells (SSCs) are responsible for maintaining spermatogenesis throughout life in the male by continuous production of daughter cells that differentiate into spermatozoa. However, no unique phenotypic markers to identify SSCs have been described. In this study, the SSC surface phenotype was characterized by using flow cytometric cell sorting in conjunction with a transplantation functional assay for SSCs. Highly enriched stem cell activity was found in the MHC class I (MHC-I)-Thy-1+c-kit- cell fraction of the mouse cryptorchid testis. There was little or no stem cell activity in any other fraction. The antigenic phenotype of the MHC-I-Thy-1+c-kit- SSCs was alpha6-integrin+CD24+alphavintegrin-Sca-1-CD34-. Subsequently, testis side population (SP) cells, which are defined by a Hoechst dye efflux assay, were identified. Their surface phenotype was found to be MHC-I+Thy-1-Sca-1+, and the transplantation assay demonstrated that the testis SP and SSCs are distinct populations. In several other tissues, the SP has been shown to contain stem cells, but we found that this characteristic does not define SSCs. The identification of a surface phenotype that allows production of a highly enriched SSC population will facilitate functional and genomic studies and enable further comparison with other stem cells. (+info)
Heat shock transcription factor 1 is involved in quality-control mechanisms in male germ cells.
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Quality-control mechanisms in spermatogenesis are important to eliminate injured or abnormal cells, thereby protecting the organism from abnormal development in the next generation. The processes of spermatogenesis are highly sensitive to high temperatures; however, the mechanisms by which injured germ cells are eliminated remain unclear. Here, we found that heat shock proteins are not induced in male germ cells in response to thermal stress, although heat shock transcription factor 1 (HSF1) is activated. Using HSF1-null mice, we showed that apoptosis of pachytene spermatocytes was markedly inhibited in testes with a single exposure to heat and in the cryptorchid testes, indicating that HSF1 promotes apoptotic cell death of pachytene spermatocytes exposed to thermal stress. In marked contrast, HSF1 acts as a cell-survival factor of more immature germ cells, probably including spermatogonia, in testes exposed to high temperatures. These results demonstrate that HSF1 has two opposite roles in male germ cells independent of the activation of heat shock genes. (+info)
Late diagnosis of cryptorchidism: a failure of medical screening?
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A retrospective review of hospital and available community records of 47 children undergoing orchidopexy in a district hospital was undertaken to determine adequacy of screening for cryptorchidism and factors associated with late referral. Twenty eight of these boys were previously examined on 108 occasions. Diagnosis was missed on 32 occasions and the record of 38 clinical examinations did not include position of testes. In the case of 16 boys (four under school age and 12 of school age) appropriate action was not taken once the diagnosis was made. Diagnosis was reliably made in school aged children but in children under the age of 1 year cryptorchidism was frequently missed by the examining doctor. It is suggested that criteria for diagnosis and referral should be agreed in any surveillance programme. Junior doctors in hospital responsible for routine clinical examination of children during admission and clinical medical officers or general practitioners during routine clinical examination of boys should be clearly instructed to examine and record the position of the testes. (+info)
Cryptorchidism: a prospective study of 7500 consecutive male births, 1984-8. John Radcliffe Hospital Cryptorchidism Study Group.
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A total of 7441 boys were examined for cryptorchidism at birth and, if present, again at 3 months of age. After excluding boys with severe congenital malformations noted at birth, the cryptorchidism rates at 3 months in babies weighing less than 2000 g, 2000-2499 g, and greater than or equal to 2500 g were 7.7%, 2.5%, and 1.41% respectively. The overall rate was 1.55%. The cryptorchidism rate at birth had increased by 35.1% and at 3 months by 92.7%, over Scorer's rates in the 1950s. Part of these increases may be attributable to differences in neonatal mortality, but the increases in babies weighing 2500 g or more of 50.2% at birth and 77.4% at 3 months are unlikely to be overestimates. At birth 1.92% of boys had bilateral cryptorchidism and 3.0% unilateral cryptorchidism. Boys with cryptorchidism at 3 months were more likely to have hypospadias, a small scrotum, and poor scrotal rugation compared with boys having normally descended testes at birth. Factors predicting descent by 3 months in babies cryptorchid at birth are birth weight, laterality and scrotal size, babies with low birth weight, bilateral cryptorchidism, and normal scrotal size being more likely to have normally descended testes by 3 months. Descent by 3 months was more likely the lower the testis along the normal pathway of descent. The orchidopexy rate at an average age of 3 years was 1.24%. This is substantially lower than in other series and lower than our estimated rate of 2.9% using Hospital In-Patient Enquiry data for England and Wales. (+info)
Glutathione S-transferase expression in the human testis and testicular germ cell neoplasia.
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Glutathione S-transferase (GST) isoenzyme expression is altered in a variety of neoplasms and the enzymes are implicated in metabolism of carcinogens and resistance to drugs, including cisplatin. We have studied GST Alpha, Pi, Mu and microsomal isoenzyme expression by immunohistochemistry in normal and cryptorchid testes, intratubal germ cell neoplasia (ITGCN), seminoma and non-seminomatous germ cell tumours. In 16 stage II-IV malignant teratoma intermediate (MTI) both orchidectomy and post-treatment residual surgical masses were studied. All four isoenzymes were strongly expressed in Leydig and Sertoli cells. GST Pi was absent from normal spermatogonia but strongly expressed by the neoplastic germ cells of ITGCN and seminoma. GST Pi was strongly expressed in all elements of teratoma, irrespective of differentiation. There were no qualitative differences in expression between primary and post-chemotherapy metastases. GST Alpha expression in teratoma correlated with epithelial differentiation. GSTs may be important in normal spermatogenesis and protection of germ cells from teratogens and carcinogens. They may have a role in testicular tumour drug resistance but this role is not well defined. GST Pi is a new marker for ITGCN. (+info)
Impaired detoxification of reactive oxygen and consequent oxidative stress in experimentally cryptorchid rat testis.
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The effect of experimental cryptorchidism on the level of oxidative stress and antioxidant functions in rat testis was studied. Adult male Sprague-Dawley rats were rendered unilaterally cryptorchid (by suturing one testis to the abdominal wall) and killed 1, 3, or 7 days after the operation. As an indicator of oxidative stress, lipid peroxidation was measured by the diene conjugation method in testis homogenates. The activities of the antioxidant enzymes were determined either in the 10,000 x g supernatant fraction (glutathione [GSH] peroxidase, GSH transferase, hexose monophosphate shunt) or in crude testis homogenates (superoxide dismutase, catalase). An expected reduction (48%) in weight of the abdominal testes was evident by postoperative Day 7. The catalytic activities per testis of superoxide dismutase (Cu/Zn form) and catalase were found to decrease in cryptorchidism. The effect was seen on the first postoperative day and was most profound on Day 7 after surgery. The principal antioxidant enzyme, superoxide dismutase, was most sensitive to cryptorchidism, the activity in the abdominal testes being 74% or 85% (per gram of tissue or per whole testis, respectively; p less than 0.01). After impairment of the reactive oxygen detoxifying capacity, lipid peroxidation was increased in the abdominal testis by 46% (p less than 0.01) on postoperative Day 7. Slight concomitant increases were detected in the activities of GSH-peroxidase (p less than 0.01), GSH-transferase (p less than 0.001), and the hexose monophosphate shunt (p less than 0.001). This effect was seen only when calculated per gram of tissue, not per whole testis.(ABSTRACT TRUNCATED AT 250 WORDS) (+info)