Electronic Data Base Systems Support the Evaluation of Male Infertility Factors, Example Cryptorchidism

A history of cryptorchidism is associated with impaired testicular function in early adulthood: a cross-sectional study of 6376 men from the general population

STUDY QUESTION

Is there a difference in testicular function in early adulthood between men born with cryptorchidism and men born with normally descended testes?

SUMMARY ANSWER

In men from the general population, a history of cryptorchidism was associated with lower total testis volume and impaired semen quality as well as altered serum levels of reproductive hormones.

WHAT IS KNOWN ALREADY

The association between cryptorchidism and testicular function is well documented in studies based on sub-fertile or infertile men recruited from a clinical setting. However, the association has not previously been investigated in men from the general population, who were unselected regarding fertility status.

STUDY DESIGN, SIZE, DURATION

This is a cross-sectional population-based study of 6376 young Danish men examined from 1996 to 2017.

PARTICIPANTS/MATERIALS, SETTING, METHODS

This study is based on young men from the greater Copenhagen area, Denmark (median age of 19 years) who were unselected regarding fertility status and semen quality. The young men delivered a semen sample, had a blood sample drawn and underwent a physical examination including assessment of testis volume. Participants completed a questionnaire regarding cryptorchidism at birth, current lifestyle and their mother’s pregnancy, after consulting their mother. The differences in markers of testicular function, including testis volume, semen parameters and reproductive hormones between men with and without a history of cryptorchidism were investigated with multiple linear regression analyses.

MAIN RESULTS AND THE ROLE OF CHANCE

The participation rate was 24% for the entire study period. Overall, a history of cryptorchidism was associated with reduced testicular function. In the adjusted models, a history of cryptorchidism was associated with a 3.5 ml lower total testis volume, determined by orchidometer (P < 0.001), 28% lower sperm concentration (95% CI: −37 to −20) and 26% lower inhibin B/FSH ratio (95% CI: −50 to −22) compared to men without a history of cryptorchidism, suggesting a reduced spermatogenetic capacity. Men with a history of cryptorchidism also had a slightly reduced Leydig cell function expressed as a 6% lower testosterone/LH ratio (95% CI: −12 to −0.7). The significant effect sizes and different markers of testicular function pointing in the same direction across the different models based on a large sample size support that the results are not chance findings.

LIMITATIONS, REASONS FOR CAUTION

Information on cryptorchidism at birth and treatment modus was obtained by retrospective self-report, and each participant only delivered one semen sample.

WIDER IMPLICATIONS OF THE FINDINGS

The results suggest that men with a history of cryptorchidism could be at increased risk of experiencing fertility problems. However, among these men there is a wide variation in semen quality and further research is needed in order to identify the subgroup of boys born with cryptorchidism who are at the greatest risk of impaired semen quality when reaching adulthood.

STUDY FUNDING/COMPETING INTEREST(S)

The study received financial support from the Research fund of Rigshospitalet, Copenhagen University Hospital; the European Union (Contract numbers BMH4-CT96-0314, QLK4-CT-1999-01422, QLK4-CT-2002-00603. FP7/2007-2013, DEER Grant agreement no. 212844); the Danish Ministry of Health; the Danish Environmental Protection Agency; A.P. Møller and wife Chastine McKinney Møllers Foundation; and Svend Andersens Foundation. None of the founders had any role in the study design, collection, analysis or interpretation of data, writing of the paper or publication decisions. The authors have nothing to declare.

TRIAL REGISTRATION NUMBER

N/A.

Prospective study of histological and endocrine parameters of gonadal function in boys with cryptorchidism

INTRODUCTION

A transient increase in gonadotropins and testosterone during mini-puberty causes gonocytes to differentiate into Ad spermatogonia, which establish male germ cell memory and male-specific DNA methylation pathways. Over half of patients with unilateral cryptorchidism and the majority of patients with bilateral cryptorchidism display an abnormal spermiogram, which indicates that unilateral cryptorchidism is a bilateral disease; therefore, it represents a serious andrological problem. The aim of this study was to evaluate relationships between hormonal parameters and testicular biopsy findings in boys with cryptorchidism.

METHOD

Seventy-one boys (median age 15 months; range 7-65 months) who underwent orchidopexy (24% had bilateral cryptorchidism) were tested for serum LH, FSH, and inhibin B. With ipsilateral testis biopsy histology, we determined the tubular fertility index (TFI), Ad spermatogonia counts, and Ad/tubular index (Ad/T). We compared age groups (<18 vs. >18 months old); groups with and without Ad spermatogonia; groups with unilateral and bilateral cryptorchidism; and extreme groups with high infertility risk (HIR; n = 12; TFI <0.2; Ad/T = 0) and low infertility risk (LIR; n = 9; TFI >0.9; Ad/T>0.02).

RESULTS

Of the specimens, 38% had no Ad spermatogonia. Age was significantly negatively correlated with TFI and Ad/T, but positively correlated with FSH. Median LH values were significantly higher in LIR than in HIR groups. Unilateral and bilateral cryptorchidism showed similar TFI, Ad/T, and hormone concentrations. The areas under ROC curves for FSH, LH, and inhibin B (0.66, 0.601, and 0.599, respectively) showed low diagnostic value for predicting HIR (no Ad spermatogonia).

CONCLUSION

Our observation of lower plasma LH levels in the group with the most pronounced testicular pathology was the opposite of what we would have expected if testicular pathological changes were caused by a primary gonadal defect. Therefore, low plasma LH levels in the HIR group confirmed the notion that this group of patients with cryptorchidism had hypogonadotropic hypogonadism. The estimated incidence of defective mini-puberty in boys with cryptorchidism could be as high as 50%. Testicular biopsies from boys with cryptorchidism lacked Ad spermatogonia. Fertility parameters worsened with age. Significantly lower basal LH in the HIR group indicated hypogonadotropic hypogonadism. Serum hormone levels could not predict histological biopsy findings.

The regulation of testicular descent and the effects of cryptorchidism

The first half of this review examines the boundary between endocrinology and embryonic development, with the aim of highlighting the way hormones and signaling systems regulate the complex morphological changes to enable the intra-abdominal fetal testes to reach the scrotum. The genitoinguinal ligament, or gubernaculum, first enlarges to hold the testis near the groin, and then it develops limb-bud-like properties and migrates across the pubic region to reach the scrotum. Recent advances show key roles for insulin-like hormone 3 in the first step, with androgen and the genitofemoral nerve involved in the second step. The mammary line may also be involved in initiating the migration. The key events in early postnatal germ cell development are then reviewed because there is mounting evidence for this to be crucial in preventing infertility and malignancy later in life. We review the recent advances in what is known about the etiology of cryptorchidism and summarize the syndromes where a specific molecular cause has been found. Finally, we cover the recent literature on timing of surgery, the issues around acquired cryptorchidism, and the limited role of hormone therapy. We conclude with some observations about the differences between animal models and baby boys with cryptorchidism.

The controversy regarding the need for hormonal treatment in boys with unilateral cryptorchidism goes on: a review of the literature

Hormonal treatment for unilateral undescended testes continues to be recommended in some countries. We reviewed the literature in favor and against this recommendation. Since the paternity rate of men with a history of unilateral undescended testes only treated with surgery is normal, the effectiveness of hormonal treatment to produce testicular descent is low, the cost is considerable, and there are potential adverse effects, hormonal treatment for boys with unilateral undescended testes should no longer be recommended.

Testicular gene expression in cryptorchid boys at risk of azoospermia

Despite timely and successful surgery, 32% of patients with bilateral and 10% with unilateral cryptorchidism will develop azoospermia. Cryptorchid boys at risk of azoospermia display a typical testicular histology of impaired mini-puberty at the time of the orchidopexy. During mini-puberty increased gonadotropin and testosterone secretion stimulate transformation of gonocytes into Ad spermatogonia. In the azoospermia risk group this transformation is to a great extent impaired. This study aimed to analyze data on whole genome expression signatures of undescended testes at risk of developing azoospermia. Twenty-three testicular biopsies from 22 boys were analyzed (19 testes from 18 boys with cryptorchidism and 4 contralateral descended testes from patients with testicular agenesis). Expression profiling identified 483 genes not or under-expressed in the azoospermia risk group compared with the control and low risk for azoospermia (LAZR) groups. Annotated loci were associated with spermatogenesis. Other significant genes were cellular defense response genes and hormone-controlled loci involved in spermatogenesis. Some genes transcribed in normal adult meiotic and post-meiotic germ cells are activated in healthy juvenile Ad spermatogonia. Thus, molecular events initiating the testicular expression program at the onset of puberty and maintaining it during adulthood occur very early in prepubertal testes. This molecular event is to a great extent impaired in the high risk for azoospermia (HAZR) group lacking Ad spermatogonia (stem cells for spermatozoa) indicating impaired mini-puberty.

Obesity and age affect male fertility potential

A case-cohort study of 2,157 patients, aged 17-67 years was performed to assess the impact of body mass index and age on male fertility. Using a multiple regression analysis across the total cohort, only age correlated significantly with all spermiogram parameters and serum hormones, but in patients aged 20-30 years (n = 617) the total sperm count was significantly negatively correlated with body mass index.

Infertility in Cryptorchidism Is Linked to the Stage of Germ Cell Development at Orchidopexy

BACKGROUND

Cryptorchidism represents the most common endocrine disease in boys, with infertility frequently observed in unilateral as well as bilateral forms. In this study, we examined the role of Ad (dark) spermatogonia for fertility in cryptorchid boys. The hypothesis to be proven was that boys lacking Ad spermatogonia will develop infertility despite a successful orchidopexy at an early age.

METHODS

To estimate total sperm count, one of the most predictive parameters of male fertility, we analyzed the ejaculatein 218 cryptorchid men and correlated it with the developmental stage of their germ cells at the time of successful surgery.

RESULTS

Abnormal sperm concentration (<40 x 10(6)/ejaculate) was found in half of the patients under the study. 47.5% of unilateral and 78% of bilateral cryptorchid males had their sperm concentration in the infertility range according to the WHO standards. If transformation into Ad spermatogonia had occurred, age-related differences in the fertility outcome was observed. The younger the unilateral cryptorchid boys were at surgery, the higher their sperm count. Age-related difference was not found in the group of cryptorchid men having had no A dark spermatogonia at time of surgery, indicating that in this group a successful orchidopexy is insufficient to prevent infertility development and, in particular, the development of azoospermia.

CONCLUSION

The presence of Ad spermatogonia at surgery is an excellent prognostic parameter for future fertility. Cryptorchid boys lacking these cells will develop infertility despite successful orchidopexy at an early age.