Leydig cell hyperplasia in cryptorchid patients: quantitative evaluation of Leydig cells in undescended and contralateral scrotal testes

Cryptorchidism and puberty

Cryptorchidism is the condition in which one or both testes have not descended adequately into the scrotum. The congenital form of cryptorchidism is one of the most prevalent urogenital anomalies in male newborns. In the acquired form of cryptorchidism, the testis that was previously descended normally is no longer located in the scrotum. Cryptorchidism is associated with an increased risk of infertility and testicular germ cell tumors. However, data on pubertal progression are less well-established because of the limited number of studies. Here, we aim to review the currently available data on pubertal development in boys with a history of non-syndromic cryptorchidism-both congenital and acquired cryptorchidism. The review is focused on the timing of puberty, physical changes, testicular growth, and endocrine development during puberty. The available evidence demonstrated that the timing of the onset of puberty in boys with a history of congenital cryptorchidism does not differ from that of non-cryptorchid boys. Hypothalamic-pituitary-gonadal hormone measurements showed an impaired function or fewer Sertoli cells and/or germ cells among boys with a history of cryptorchidism, particularly with a history of bilateral cryptorchidism treated with orchiopexy. Leydig cell function is generally not affected in boys with a history of cryptorchidism. Data on pubertal development among boys with acquired cryptorchidism are lacking; therefore, more research is needed to investigate pubertal progression among such boys.

The lack of HSD17B3 in male mice results in disturbed Leydig cell maturation and endocrine imbalance akin to humans with HSD17B3 deficiency

Hydroxysteroid (17β) dehydrogenase type 3 (HSD17B3) deficiency causes a disorder of sex development in humans, where affected males are born with female-appearing external genitalia, but are virilized during puberty. The hormonal disturbances observed in the Hsd17b3 knockout mice (HSD17B3KO), generated in the present study, mimic those found in patients with HSD17B3 mutations. Identical to affected humans, serum T in the adult HSD17B3KO mice was within the normal range, while a striking increase was detected in serum A-dione concentration. This resulted in a marked reduction of the serum T/A-dione ratio, a diagnostic hallmark for the patients with HSD17B3 deficiency. However, unlike humans, male HSD17B3KO mice were born with normally virilized phenotype, but presenting with delayed puberty. In contrast to the current belief, data from HSD17B3KO mice show that the circulating T largely originates from the testes, indicating a strong compensatory mechanism in the absence of HSD17B3. The lack of testicular malignancies in HSD17B3KO mice supports the view that testis tumors in human patients are due to associated cryptorchidism. The HSD17B3KO mice presented also with impaired Leydig cell maturation and signs of undermasculinization in adulthood. The identical hormonal disturbances between HSD17B3 deficient knockout mice and human patients make the current mouse model valuable for understanding the mechanism of the patient phenotypes, as well as endocrinopathies and compensatory steroidogenic mechanisms in HSD17B3 deficiency.

Immunohistochemical localization of glucose transporter 1 and 3 in the scrotal and abdominal testes of a dog

Glucose is essential for testicular function; the uptake of carbohydrate-derived glucose by cells is mediated by glucose transporters (GLUTs). In the present study, we investigated the activity of GLUT1 and GLUT3, the two main isoforms of GLUTs found in testes, in the left scrotal and right abdominal testes of a German Shepherd dog. Immunohistochemical analysis showed that GLUT1 immunoreactivity was absent in the scrotal and abdominal testes. In contrast, weak to moderate GLUT3 immunoreactivity was observed in mature spermatocytes as well as spermatids in the scrotal testis. In the abdominal testis, relatively strong GLUT3 immunoreactivity was detected in Leydig cells only and was absent in mature spermatocytes and spermatids. GLUT3 immunoreactivity was significantly decreased in the tubular region of abdominal testis and significantly increased in the extra-tubular (interstitial) region of abdominal testis compared to observations in the each region of scrotal testis, respectively. These results suggest that GLUT3 is the major glucose transporter in the testes and that abdominal testes may increase the uptake of glucose into interstitial areas, leading to an increased risk of developing cancer.

Individualized Treatment Guidelines for Postpubertal Cryptorchidism

Cryptorchidism is a well-known congenital anomaly in children. However, its diagnosis is often delayed for reasons including patient unawareness or denial of abnormal findings in the testis. Moreover, it has been difficult to establish an optimal treatment strategy for postpubertal cryptorchidism, given the small number of patients. Unlike cryptorchidism in children, postpubertal cryptorchidism is associated with an increased probability of neoplasms, which has led orchiectomy to be the recommended treatment. However, routine orchiectomy should be avoided in some cases due to quality-of-life issues and the potential risk of perioperative mortality. Based on a literature review, this study proposes individualized treatment guidelines for postpubertal cryptorchidism.

Non-tumoural parenchyma in Leydig cell tumours: pathogenetic considerations

Little is known about the pathogenesis of Leydig cell tumours (LCTs) of the testis. The observation of several associated dysgenetic features in the non-tumoural parenchyma and in the contralateral testes of men with testicular germ cell neoplasms has served as the basis to propose that there may be a common mechanism for different male reproductive disorders. However, the possible relationship between LCTs and other testicular lesions has not been explored. Here we describe the presence of primary lesions in the non-tumoural parenchyma of testes with LCT, from which we try to establish possible pathogenetic associations. We studied the non-tumoural parenchyma adjacent to 16 LCT specimens. Parameters as Leydig cell hyperplasia (LCHY), qualitative evaluation of the germinal epithelium and spermatogenesis, the presence of Sertoli cell-only tubules (SCOT), and the Sertoli cell nuclear morphology were consistently assessed in all cases. SCOT associated with Sertoli cell dysgenetic morphology was the most frequent finding, present in 50% of the cases. Another interesting finding was the presence of LCHY in four cases (25%). Abnormal spermatogenesis was found in 81.25% of the cases, and it consisted of lesions of the adluminal or basal compartments of seminiferous tubules. The occurrence of either dysgenetic Sertoli cells or LCHY adjacent to LCTs could represent primary anomalies, resulting from a common insult also involved in tumourigenesis. The abnormalities in spermatogenesis observed here are likely to represent consequences of either tumour compression or abnormal hormonal production. The significance of these associations merits further investigation regarding a common pathogenesis.

Men with nonobstructive azoospermia have Leydig cell hypertrophy but not hyperplasia

PURPOSE

We determined whether testicular histology in men with spermatogenic failure due to nonobstructive azoospermia shows true Leydig cell hyperplasia.

MATERIALS AND METHODS

Testicular biopsy specimens from 17 patients evaluated for infertility were retrospectively analyzed. Interstitial, tubular and Leydig cell volume were quantitatively evaluated. The total volume and number of Leydig cells per testicle were then calculated.

RESULTS

In 10 patients with obstructive azoospermia testicular histology showed normal spermatogenic function, while 7 had nonobstructive azoospermia. Average testicular volume plus or minus standard deviation was significantly larger in those with obstructive versus nonobstructive azoospermia (18.0 +/- 7.0 versus 9.3 +/- 8.7 cc, p = 0.025). Interstitial versus tubular volume was 32% of the total testis in the obstructive and 63% in the nonobstructive groups (p = 0.003). Although Leydig cell volume was proportionally greater in men with nonobstructive versus obstructive azoospermia (13.3% versus 0.05%, p = 0.045), there was no significant difference in the average number of Leydig cells per testicle (3.96 x 10 and 6.17 x 10, respectively, p = 0.16). The average volume of individual Leydig cells was significantly greater in men with the nonobstructive condition (253.0 +/- 98.7 versus 174.0 +/- 57.7 microm., p = 0.045).

CONCLUSIONS

These results suggest that men with nonobstructive azoospermia and those with normal spermatogenesis have an equivalent number of Leydig cells. However, the Leydig cells are hypertrophic and occupy a larger proportion of total testis volume in men with nonobstructive azoospermia. Therefore, patients with spermatogenic failure show Leydig cell hypertrophy but not hyperplasia.

Leydig cells within the aspermatogenic seminiferous tubules

Cells identical to Leydig cells were found within a peritubular boundary layer and even inside a basal lamina of seminiferous tubules in three male patients (two with inguinal cryptorchism and one with infertility). The seminiferous tubules of all patients showed a moderate to marked thickening of the boundary layer and a complete loss of spermatogenic cells. The "ectopic Leydig cells" were characterized by the presence of Reinke crystals or an extensively developed smooth endoplasmic reticulum. These cells were believed to have differentiated in situ from myoid cells within the boundary layer and also to have invaded from the interstitial tissue in the form of mature Leydig cells. The occurrence of ectopic Leydig cells appeared to parallel the extent of loss of the Sertoli cells and also that of the thickening of the boundary layer. The functional significance of the ectopic occurrence might be implicated in the impaired spermatogenesis.

Elastic fibers in tunica propria of undescended and contralateral scrotal testes from cryptorchid patients

Elastic fibers in the tunica propria of the testes from cryptorchid patients and normal fertile adults were examined by light (Weigert resorcin-fuchsin stain) and electron microscopic techniques. In the testes from normal fertile adults, elastic fibers were proved to exist in the tunica propria by light and electron microscopy, and were located in the fibrous and cellular layers of the tunica propria. In the undescended testes from the cryptorchid patients, during prepubertal and pubertal periods, elastic fibers could not be visualized in the tunica propria, but were found after puberty. The positive Weigert reaction of the tunica propria in the undescended testes from postpubertal cryptorchid patients, however, was markedly weaker than that in normal control patients, suggesting diminution of elastic fibers. This diminution of elastic fibers in the undescended testes from postpubertal cryptorchid patients was also substantiated by electron microscopy. However, in the contralateral scrotal testes, elastic fibers appeared during puberty and were observed after puberty in the same manner as in normal testes. Thus, the present study suggested retarded appearance of elastic fibers in puberty and impaired development of those fibers after puberty, in the undescended testes of cryptorchid patients.