1
|
Sarila G, Hutson JM, Vikraman J. Testicular descent: A review of a complex, multistaged process to identify potential hidden causes of UDT. J Pediatr Surg 2022; 57:479-487. [PMID: 34229874 DOI: 10.1016/j.jpedsurg.2021.05.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2021] [Revised: 04/29/2021] [Accepted: 05/10/2021] [Indexed: 12/16/2022]
Abstract
BACKGROUND/PURPOSE What causes normal descent of the testis in a fetus, and what goes wrong with this complex process to cause undescended testes (UDT), or cryptorchidism? Over the last 2 decades, most authors searching for the cause(s) of UDT have looked at the 2 main hormones involved, insulin-like hormone 3 (Insl3) and testosterone (T)/ dihydrotestosterone (DHT), and their known upstream (hypothalamic-pituitary axis) and intracellular 'downstream' pathways. Despite these detailed searches, the genetic causes of UDT remain elusive, which suggest the aetiology is multifactorial, and/or we are looking in the wrong place. METHODS In this review we highlight the intricate morphological steps involved in testicular descent, which we propose may contain the currently 'idiopathic' causes of UDT. By integrating decades of research, we have underlined many areas that have been overlooked in the search for causes of UDT. RESULTS It is quite likely that the common causes of UDT are still hidden in these areas, and we suggest examining these processes is worthwhile in the hope of finding the common genetic anomalies that lead to cryptorchidism. Given the fact that a fibrous barrier preventing descent is often described at orchidopexy, examination of the extracellular matrix enzymes needed to allow gubernacular migration may be a fruitful place to start. CONCLUSION This review of the complex anatomical steps and hormonal regulation of testicular descent highlights many areas of morphology and signalling pathways that have been overlooked in the search for causes of UDT.
Collapse
Affiliation(s)
- Gulcan Sarila
- Surgery, Murdoch Children's Research Institute, Melbourne, Australia
| | - John M Hutson
- Surgery, Murdoch Children's Research Institute, Melbourne, Australia; University of Melbourne, Melbourne, Australia; Urology Department, The Royal Children's Hospital, Parkville, Australia
| | - Jaya Vikraman
- Surgery, Murdoch Children's Research Institute, Melbourne, Australia
| |
Collapse
|
2
|
Logsdon NT, Sampaio FJB, Favorito LA. The role of intra-abdominal pressure in human testicular migration. Int Braz J Urol 2021; 47:36-44. [PMID: 32758302 PMCID: PMC7712702 DOI: 10.1590/s1677-5538.ibju.2021.99.03] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2020] [Accepted: 08/01/2020] [Indexed: 11/22/2022] Open
Abstract
Objectives: This review aims to study the role of the abdominal wall in testicular migration process during the human fetal period. Materials and Methods: We performed a descriptive review of the literature about the role of the abdominal wall in testicular migration during the human fetal period. Results: The rise in intra-abdominal pressure is a supporting factor for testicular migration. This process has two phases: the abdominal and the inguinal-scrotal stages. The passage of the testis through the inguinal canal occurs very quickly between 21 and 25 WPC. Bilateral cryptorchidism in Prune Belly syndrome is explained by the impaired contraction of the muscles of the abdominal wall; mechanical obstruction due to bladder distention and structural alteration of the inguinal canal, which hampers the passage of the testis during the inguinoscrotal stage of testicular migration. Abdominal wall defects as gastroschisis and omphaloceles are associated with undescended testes in around 30 to 40% of the cases. Conclusions: Abdominal pressure wound is an auxiliary force in testicular migration. Patients with abdominal wall defects are associated with undescendend testis in more than 30% of the cases probably due to mechanical factors; the Prune Belly Syndrome has anatomical changes in the anterior abdominal wall that hinder the increase of intra-abdominal pressure which could be the cause of cryptorchidism in this syndrome.
Collapse
Affiliation(s)
- Natasha T Logsdon
- Unidade de Pesquisa Urogenital, Universidade do Estado do Rio de Janeiro - Uerj, Rio de Janeiro, RJ, Brasil
| | - Francisco J B Sampaio
- Unidade de Pesquisa Urogenital, Universidade do Estado do Rio de Janeiro - Uerj, Rio de Janeiro, RJ, Brasil
| | - Luciano Alves Favorito
- Unidade de Pesquisa Urogenital, Universidade do Estado do Rio de Janeiro - Uerj, Rio de Janeiro, RJ, Brasil
| |
Collapse
|
3
|
Inguinoscrotal stage of testicular descent: analysis in 217 human fetuses. J Pediatr Urol 2020; 16:198-204. [PMID: 32107183 DOI: 10.1016/j.jpurol.2020.01.016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2019] [Accepted: 01/22/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND Testicular descent is a complex process of relevant importance for the comprehension of cryptorchidism. Studies about the inguinoscrotal stage of testicular migration correlating the testicular position with fetal parameters are rare in the literature. Our hypothesis is that the transition of the testis by the inguinal canal is a very fast process and occurs at the end of the third gestational trimester. AIM To analyze the inguinoscrotal stage of testicular descent during the human fetal period. STUDY DESIGN This is an observational study in human fetuses. We studied 217 human male fetuses ranging from 10 to 35 weeks postconception (WPC). The fetuses were well preserved and evaluated regarding crown-rump length (CRL) and body weight before dissection. Testicular position was classified as: a) abdominal, when the testis was proximal to the internal ring; b) inguinal, when it was found between the internal and external inguinal rings; and c) scrotal, when being inside the scrotum. Means were statistically compared using the unpaired t-test (P < 0.05). RESULTS Of the 434 testes, 329 (75.8%) were abdominal, 48 (11.05%) were inguinal, and 57 (13.13%) were scrotal. The first case of inguinal testis was observed in a fetus with 17 WPC, 203 g, and 15 cm CRL. The 48 inguinal testes were observed in 29 fetuses (13.36%), aged between 17 and 29 WPC, weighing between 203 and 1220 g, and with CRL between 15 and 27.5 cm. Of the 29 fetuses with inguinal testes, 23 (79.32%) were aged between 20 and 26 WPC; 3 (10.34%) had 17 WPC; and 3 (10.34%) had more than 26 WPC. All the fetuses with more than 30 WPC had testes in the scrotum. We did not observe fetuses less than 17 WPC with the testes in the canal. DISCUSSION We found that all fetuses with more than 30 WPC had the testes located in the scrotum and that in fetuses between 17 WPC and 25 WPC, 38 testes (8.7% of the sample) were situated in the canal and only 1 testis in a fetus with 25 WPC was located in the scrotum, showing that the second stage of testicular migration through the inguinal canal rarely occurs before the 20th WPC. CONCLUSION The inguinoscrotal stage of testicular descent is a fast process, observed only in 13% of the fetuses and occurring with more intensity between 20 and 26 WPC.
Collapse
|
4
|
Morgan JT, Robbins AK, Mateson AB, Sawamoto K, Tomatsu S, Gray DR, Gleghorn JP, Barthold JS. Regional Variation in Androgen Receptor Expression and Biomechanical Properties May Contribute to Cryptorchidism Susceptibility in the LE/orl Rat. Front Endocrinol (Lausanne) 2018; 9:738. [PMID: 30568634 PMCID: PMC6290328 DOI: 10.3389/fendo.2018.00738] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Accepted: 11/20/2018] [Indexed: 11/13/2022] Open
Abstract
Background: The process of testicular descent requires androgen and insulin-like 3, hormones secreted by fetal Leydig cells. Knowledge concerning distinct and common functions of these hormones in regulating development of the fetal gubernaculum remains limited and/or conflicting. The current studies were designed to better define characteristics of androgen receptor (AR) expression, function and regulation, as well as the biomechanical properties of normal and cryptorchid gubernaculum during fetal development. Methods: We studied fetal gubernacula from Long Evans outbred (LE/wt) rats and an inbred (LE/orl) strain with an inherited form of cryptorchidism associated with an AR signaling defect. Gubernacular cells or whole organs obtained from LE/wt and LE/orl fetal gubernacula underwent AR immunostaining and quantitative image analysis. The effects of dihydrotestosterone (DHT) on AR expression, muscle fiber morphology, hyaluronan (HA) levels and glycosaminoglycan (GAG) content were measured in LE/wt gubernacula. Finally, the spatial mechanics of freshly harvested LE/wt and LE/orl fetal gubernacula were compared using micropipette aspiration. Results: AR is expressed in the nucleus of mesenchymal core, tip and cord cells of the embryonic (E) day 17 and 21 fetal gubernaculum, and is enhanced by DHT in primary cultures of gubernacular mesenchymal cells. Enhanced AR expression at the tip was observed in LE/wt but not LE/orl gubernacula. In in vitro studies of whole mount fetal gubernaculum, DHT did not alter muscle fiber morphology, HA content or GAG production. Progressive swelling with reduced cellular density of the LE/wt gubernaculum at E19-21 was associated with increased central stiffness in LE/wt but not in LE/orl fetuses. Conclusions: These data confirm nuclear AR expression in gubernacular mesenchyme with distal enhancement at the tip/cord region in LE/wt but not LE/orl rat fetuses. DHT enhanced cellular AR expression but had no major effects on muscle morphology or matrix composition in the rat fetal gubernaculum in vitro. Regional increased stiffness and decreased cell density between E19 and E21 were observed in LE/wt but not LE/orl fetal gubernacula. Developmental differences in cell-specific AR expression in LE/orl fetal gubernacula may contribute to the dysmorphism and aberrant function that underlies cryptorchidism susceptibility in this strain.
Collapse
Affiliation(s)
- Joshua T. Morgan
- Department of Bioengineering, University of California, Riverside, Riverside, CA, United States
- *Correspondence: Joshua T. Morgan
| | - Alan K. Robbins
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Abigail B. Mateson
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Kazuki Sawamoto
- Department of Orthopedics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Shunji Tomatsu
- Department of Orthopedics, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Dione R. Gray
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| | - Jason P. Gleghorn
- Department of Biomedical Engineering, University of Delaware, Newark, DE, United States
| | - Julia Spencer Barthold
- Nemours Biomedical Research, Division of Urology, Nemours/Alfred I. duPont Hospital for Children, Wilmington, DE, United States
| |
Collapse
|
5
|
Favorito LA, Bernardo FO, Costa SF, Sampaio FJB. Is there a trans-abdominal testicular descent during the second gestational trimester? Study in human fetuses between 13 and 23 weeks post conception. Int Braz J Urol 2017; 42:558-63. [PMID: 27286121 PMCID: PMC4920575 DOI: 10.1590/s1677-5538.ibju.2015.0301] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 09/08/2015] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES To confirm if a real inner descend of testis occurs, correlating the testicular position with fetal parameters and analyzing the position of the testes relative to the internal ring. MATERIAL AND METHODS Twenty nine human fetuses between 13 and 23 weeks post conception (WPC) were studied. The fetuses were carefully dissected with the aid of a stereoscopic lens with 16/25X magnification and testicular position observed. With the aid of a digital pachymeter the distance between the lower pole of the kidney and the upper extremity of the testis (DK-T) was measured to show the position of the testis. During the dissection we also indicated the position of the testes relative to the internal ring. Means were statistically compared using simple linear regression and the paired T-test. RESULTS The 58 testes had abdominal position. The DK-T in the right side measured between 0.17 and 1.82cm (mean=0.79cm) and in the left side it was between 0.12 and 1.84cm (mean=0.87cm), without statistically differences (p=0.0557). The linear regression analysis indicated that DK-T in both sides correlated significantly and positively with fetal age. All fetuses with more than 20 WPC, heavier than 350g and with CRL over 22cm had a greater distance than the average DK-T. We xobserved that the 58 testis remains adjacent to the internal ring throughout the period studied. CONCLUSIONS The testes remains adjacent to the internal ring throughout the period studied, indicating that there is no real trans-abdominal testicular descent during the second gestational trimester.
Collapse
Affiliation(s)
- Luciano A Favorito
- Unidade de Pesquisa Urogenital, Universidade Estadual do Rio de Janeiro, RJ, Brasil
| | - Fabio O Bernardo
- Unidade de Pesquisa Urogenital, Universidade Estadual do Rio de Janeiro, RJ, Brasil
| | - Suelen F Costa
- Unidade de Pesquisa Urogenital, Universidade Estadual do Rio de Janeiro, RJ, Brasil
| | | |
Collapse
|
6
|
Vikraman J, Hutson JM, Li R, Thorup J. The undescended testis: Clinical management and scientific advances. Semin Pediatr Surg 2016; 25:241-8. [PMID: 27521715 DOI: 10.1053/j.sempedsurg.2016.05.007] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Undescended testes (UDT), where one or both testes fail to migrate to the base of the scrotum, can be congenital (2-5% of newborn males) or acquired (1-2% of males). The testis may be found in any position along its usual line of descent. Cryptorchidism affects the developing testicular germ cells and increases the risk of infertility and malignancy. Clinical management aims to preserve spermatogenesis and prevent the increased risk of seminoma. Examination to document the testicular position will guide the need for imaging, medical management and the surgical approach to orchidopexy.
Collapse
Affiliation(s)
- Jaya Vikraman
- Douglas Stephens Surgical Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia
| | - John M Hutson
- Douglas Stephens Surgical Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia; Department of Paediatrics, The University of Melbourne, Melbourne, Victoria, Australia; Department of Urology, The Royal Children׳s Hospital, 50 Flemington Rd, Parkville, Victoria 3052, Australia.
| | - Ruili Li
- Douglas Stephens Surgical Group, Murdoch Childrens Research Institute, Melbourne, Victoria, Australia
| | - Jorgen Thorup
- Department of Paediatric Surgery and Surgical Clinic, Rigshospitalet, Copenhagen, Denmark; Faculty of Health and Medical Sciences, Copenhagen University, Copenhagen, Denmark
| |
Collapse
|
7
|
Favorito LA, Costa SF, Julio-Junior HR, Sampaio FJB. The importance of the gubernaculum in testicular migration during the human fetal period. Int Braz J Urol 2015; 40:722-9. [PMID: 25615240 DOI: 10.1590/s1677-5538.ibju.2014.06.02] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Accepted: 10/31/2014] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The objective of this review is to study the role of the gubernaculum in the testicular migration process during the human fetal period. MATERIALS AND METHODS We performed a descriptive review of the literature about the role of the gubernaculum in testicular migration during the human fetal period. RESULTS In the first phase of testicular migration, the gubernaculum enlarges to hold the testis near the groin and in the second phase the gubernaculum migrates across the pubic region to reach the scrotum. The proximal portion of the gubernaculum is attached to the testis and epididymis and the presence of multiple insertions in the distal gubernaculum is extremely rare. The presence of muscle and nerves in the human gubernaculum is very poor. The gubernaculum of patients with cryptorchidism has more fibrous tissue and less collagen and when the patients are submitted to hormonal treatment, the gubernaculum components alter significantly. CONCLUSIONS The gubernaculum presents significant structural modifications during testicular migration in human fetuses.
Collapse
Affiliation(s)
| | - Suelen F Costa
- Urogenital Research Unit, State University of Rio de Janeiro, Brazil
| | | | | |
Collapse
|
8
|
Abstract
Testicular descent occurs in two morphologically distinct phases, each under different hormonal control from the testis itself. The first phase occurs between 8 and 15 weeks when insulin-like hormone 3 (Insl3) from the Leydig cells stimulates the gubernaculum to swell, thereby anchoring the testis near the future inguinal canal as the foetus grows. Testosterone causes regression of the cranial suspensory ligament to augment the transabdominal phase. The second, or inguinoscrotal phase, occurs between 25 and 35 weeks, when the gubernaculum bulges out of the external ring and migrates to the scrotum, all under control of testosterone. However, androgen acts mostly indirectly via the genitofemoral nerve (GFN), which produces calcitonin gene-related peptide (CGRP) to control the direction of migration. In animal models the androgen receptors are in the inguinoscrotal fat pad, which probably produces a neurotrophin to masculinise the GFN sensory fibres that regulate gubernacular migration. There is little direct evidence that this same process occurs in humans, but CGRP can regulate closure of the processus vaginalis in inguinal hernia, confirming that the GFN probably mediates human testicular descent by a similar mechanism as seen in rodent models. Despite increased understanding about normal testicular descent, the common causes of cryptorchidism remain elusive.
Collapse
|
9
|
Hoxa-11 maintains cell proliferation in the mouse gubernaculum to facilitate testicular descent. J Pediatr Surg 2013; 48:2431-6. [PMID: 24314182 DOI: 10.1016/j.jpedsurg.2013.08.019] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2013] [Accepted: 08/26/2013] [Indexed: 02/02/2023]
Abstract
INTRODUCTION The gubernaculum is a structure vital for guiding testicular descent. The Homeobox gene, Hoxa-11, is involved in patterning embryonic structures and is necessary for gubernacular development, as Hoxa-11 knock-out mice exhibit abnormal gubernacula and undescended testes. We aimed to elucidate how testicular descent fails by examining cell proliferation and androgen receptor (AR) expression in Hoxa-11 KO mice gubernacula. METHODS Postnatal day 2 wild type (n=6) and Hoxa-11 KO mice (n=6), were prepared for immunohistochemistry and confocal microscopy using antibodies against androgen receptor, slow skeletal myosin (My32), and Ki67, a marker of cell proliferation. RESULTS The gubernacula of Hoxa-11 KO mice were hypocellular compared with WT. AR was present in the gubernaculum and abutting inguinal fat pad in both WT and Hoxa-11 KO with no difference in expression. Slow skeletal myosin was present in a clear 'swirl' in the growth centre of WT animals which was absent in the Hoxa-11 KO mice. Ki67, expressed in the growth centre and cremaster muscle in WT, was greatly decreased in Hoxa-11 KO. CONCLUSION Hoxa-11 may regulate fibroblast proliferation in the gubernaculum, as it does in human uterosacral ligaments, allowing formation of the 'growth centre' within the bulb and facilitating myogenesis and elongation to the scrotum. Polymorphisms in Hoxa-11 may contribute to the aetiology of human cryptorchidism.
Collapse
|
10
|
Hutson JM, Southwell BR, Li R, Lie G, Ismail K, Harisis G, Chen N. The regulation of testicular descent and the effects of cryptorchidism. Endocr Rev 2013; 34:725-52. [PMID: 23666148 DOI: 10.1210/er.2012-1089] [Citation(s) in RCA: 118] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
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.
Collapse
Affiliation(s)
- John M Hutson
- Urology Department, Royal Children's Hospital, Parkville 3052, Victoria, Australia.
| | | | | | | | | | | | | |
Collapse
|
11
|
Harisis GN, Chen N, Farmer PJ, Bodemer D, Li R, Sourial M, Southwell BR, Balic A, Hutson JM. Wnt signalling in testicular descent: a candidate mechanism for cryptorchidism in Robinow syndrome. J Pediatr Surg 2013; 48:1573-7. [PMID: 23895974 DOI: 10.1016/j.jpedsurg.2012.08.038] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 08/31/2012] [Accepted: 08/31/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND/AIMS Robinow syndrome is caused by mutations in Wnt-5a or its receptor Ror2 and can lead to cryptorchidism, though the mechanisms are unclear. Wnt-5a knock-out mice fail to undergo gubernacular swelling, similar to insulin-like hormone 3 (INSl-3) knock-out mice. We aimed to characterise Wnt-5a and Ror2 expression in rat gubernacula to better understand how Wnt-5a signalling affects testicular descent. METHODS Sprague-Dawley rats (n = 27) were collected with ethics approval (A644) at embryonic days (E) 15, 17, 19 and postnatal day (D) 2. Control and antiandrogen-treated groups were processed for immunohistochemistry for Wnt-5a, Ror2 and β-catenin. Sagittal sections were examined using confocal microscopy. RESULTS Wnt-5a and Ror2 were strongly expressed in the gubernacular bulb at E17 controls, their levels declining at E19 and almost absent by D2. Wnt-5a significantly co-localised with the important transcription factor β-catenin at E17. There was no obvious difference in staining with androgen blockade. CONCLUSION Wnt-5a, through Ror2 and β-catenin may play a vital role in regulating the gubernacular swelling reaction downstream of INSL-3. Human mutations in Wnt-5a or Ror2 could prevent early gubernacular growth, as suggested by undescended testes in 70% of patients with Robinow Syndrome.
Collapse
Affiliation(s)
- George N Harisis
- Douglas Stephens Surgical Research Laboratory, Murdoch Children's Research Institute, Melbourne, Australia
| | | | | | | | | | | | | | | | | |
Collapse
|
12
|
Vandenberg LN, Schaeberle CM, Rubin BS, Sonnenschein C, Soto AM. The male mammary gland: a target for the xenoestrogen bisphenol A. Reprod Toxicol 2013; 37:15-23. [PMID: 23348055 DOI: 10.1016/j.reprotox.2013.01.002] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2012] [Revised: 01/04/2013] [Accepted: 01/11/2013] [Indexed: 12/13/2022]
Abstract
Males of some strains of mice retain their mammary epithelium even in the absence of nipples. Here, we have characterized the mammary gland in male CD-1 mice both in whole mounts and histological sections. We also examined the effects of bisphenol A (BPA), an estrogen mimic that alters development of the female mouse mammary gland. BPA was administered at a range of environmentally relevant doses (0.25-250μg/kg/day) to pregnant and lactating mice and then the mammary glands of male offspring were examined at several periods in adulthood. We observed age- and dose-specific effects on mammary gland morphology, indicating that perinatal BPA exposures alter the male mammary gland in adulthood. These results may provide insight into gynecomastia, the most common male breast disease in humans, where proliferation of the mammary epithelium leads to breast enlargement.
Collapse
Affiliation(s)
- Laura N Vandenberg
- Tufts University, Department of Biology, and Center for Regenerative & Developmental Biology, 200 Boston Avenue, Suite 4600, Medford, MA 02155, United States
| | | | | | | | | |
Collapse
|
13
|
Su S, Farmer PJ, Li R, Sourial M, Buraundi S, Bodemer D, Southwell BR, Hutson JM. Regression of the Mammary Branch of the Genitofemoral Nerve May be Necessary for Testicular Descent in Rats. J Urol 2012; 188:1443-8. [DOI: 10.1016/j.juro.2012.02.041] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Indexed: 10/28/2022]
Affiliation(s)
- Shu Su
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
| | - Pamela J. Farmer
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Ruili Li
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Magdy Sourial
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Silverton Buraundi
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Daniela Bodemer
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - Bridget R. Southwell
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
| | - John M. Hutson
- Department of Pediatrics, University of Melbourne, Parkville, Victoria, Australia
- FD Stephens Research Laboratory, Murdoch Children's Research Institute, Parkville, Victoria, Australia
- Department of Urology, Royal Children's Hospital, Parkville, Victoria, Australia
| |
Collapse
|
14
|
Kaftanovskaya EM, Huang Z, Barbara AM, De Gendt K, Verhoeven G, Gorlov IP, Agoulnik AI. Cryptorchidism in mice with an androgen receptor ablation in gubernaculum testis. Mol Endocrinol 2012; 26:598-607. [PMID: 22322597 DOI: 10.1210/me.2011-1283] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Androgens play a critical role in the development of the male reproductive system, including the positioning of the gonads. It is not clear, however, which developmental processes are influenced by androgens and what are the target tissues and cells mediating androgen signaling during testicular descent. Using a Cre-loxP approach, we have produced male mice (GU-ARKO) with conditional inactivation of the androgen receptor (Ar) gene in the gubernacular ligament connecting the epididymis to the caudal abdominal wall. The GU-ARKO males had normal testosterone levels but developed cryptorchidism with the testes located in a suprascrotal position. Although initially subfertile, the GU-ARKO males became sterile with age. We have shown that during development, the mutant gubernaculum failed to undergo eversion, a process giving rise to the processus vaginalis, a peritoneal outpouching inside the scrotum. As a result, the cremasteric sac did not form properly, and the testes remained in the low abdominal position. Abnormal development of the cremaster muscles in the GU-ARKO males suggested the participation of androgens in myogenic differentiation; however, males with conditional AR inactivation in the striated or smooth muscle cells had a normal testicular descent. Gene expression analysis showed that AR deficiency in GU-ARKO males led to the misexpression of genes involved in muscle differentiation, cell signaling, and extracellular space remodeling. We therefore conclude that AR signaling in gubernacular cells is required for gubernaculum eversion and outgrowth. The GU-ARKO mice provide a valuable model of isolated cryptorchidism, one of the most common birth defects in newborn boys.
Collapse
Affiliation(s)
- Elena M Kaftanovskaya
- Department of Human and Molecular Genetics, Herbert Wertheim College of Medicine, Florida International University, 11200 SW 8th Street, Miami, Florida 33199, USA
| | | | | | | | | | | | | |
Collapse
|
15
|
Nation TR, Buraundi S, Balic A, Farmer PJ, Newgreen D, Southwell BR, Hutson JM. The effect of flutamide on expression of androgen and estrogen receptors in the gubernaculum and surrounding structures during testicular descent. J Pediatr Surg 2011; 46:2358-62. [PMID: 22152882 DOI: 10.1016/j.jpedsurg.2011.09.026] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/03/2011] [Indexed: 11/16/2022]
Abstract
BACKGROUND/PURPOSE Inguinoscrotal testicular descent is controlled by androgens between embryonic days E16-19, but androgen receptor (AR) and estrogen receptor (ER) locations are unknown. We aimed to find AR, ERα, and ERβ in the gubernaculum and inguinal fat pad (IFP) in normal rats and after flutamide treatment. METHODS Sprague-Dawley timed-mated rats were injected with flutamide (75 mg/kg body weight/5% ethanol + oil) on E16-19 or vehicle alone. Male fetuses or pups (5-10/group) were collected at E16; E19; and postnatal (P) days 0, 2, 4, 8. Sections were prepared for hematoxylin and eosin or immunohistochemistry for AR, ERα, and ERβ. Receptor labeling was quantitated as distinct nuclear labeling/100 μm(2) in gubernaculum and IFP. RESULTS There was minimal gubernacular AR-labeling until E19, dramatically increasing postnatally. By contrast, at E16-E19 there was significant IFP AR immunoreactivity suppressed by flutamide (P < .05). No ERα expression was observed, but ERβ was expressed in both gubernaculum and IFP, maximally at E16, but unchanged by flutamide. CONCLUSIONS During the androgen sensitivity window (E16-19), the gubernaculum contains ERβ but minimal ERα or AR, while the IFP, which is supplied by the genitofemoral nerve, contains abundant AR that are flutamide-sensitive. These results suggest that the IFP could be the site of androgenic action controlling gubernacular development.
Collapse
|
16
|
Chen N, Harisis GN, Farmer P, Buraundi S, Sourial M, Southwell BR, Balic A, Hutson JM. Gone with the Wnt: the canonical Wnt signaling axis is present and androgen dependent in the rodent gubernaculum. J Pediatr Surg 2011; 46:2363-9. [PMID: 22152883 DOI: 10.1016/j.jpedsurg.2011.09.032] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2011] [Accepted: 09/03/2011] [Indexed: 01/15/2023]
Abstract
BACKGROUND/AIMS How androgens control inguinoscrotal descent remains controversial but may include canonical Wnt signaling via the transcriptional co-activator β-catenin. The canonical Wnt pathway transcribes genes regulating mesenchymal cell migration, fate, extracellular matrix remodeling, and in addition Axin2, a feedback product that reliably identifies Wnt activation. The relationship between β-catenin and androgen receptor warranted investigation into the involvement of the canonical Wnt pathway in testicular descent. METHODS Gubernacula from male Sprague-Dawley control (n = 22) and flutamide-treated (n = 18) rats at E17, E19, and D0 time-points were processed for immunohistochemistry. Sagittal sections stained for presence of androgen receptor, Axin2, and β-catenin were analyzed by fluorescent confocal microscopy. RESULTS At E19, β-catenin was strongly expressed in the membrane of developing cremaster muscle cells and the cytoplasm of gubernacular core cells. Axin2 expression was ubiquitous in nuclei of gubernacular mesenchymal cells, representing canonical Wnt signaling. After androgen blockade, Axin2 was conspicuously absent in the fibroblasts of the gubernacular core while remaining unaffected elsewhere. Reduced staining of Axin2 in E17 and D0 gubernacula suggests that Wnt signaling coincides with androgen programming. CONCLUSION Axin2 expression in the E19 gubernaculum confirms canonical Wnt pathway activation. Its absence in the core of flutamide-treated gubernacula indicates Wnt down-regulation. As androgen is required for inguinoscrotal descent, downstream Wnt signaling may control initial gubernacular remodeling. Defects in this complex molecular process may play a role in cryptorchidism.
Collapse
Affiliation(s)
- Nan Chen
- Murdoch Children's Research Institute, Melbourne, Australia
| | | | | | | | | | | | | | | |
Collapse
|
17
|
Lie G, Hutson JM. The role of cremaster muscle in testicular descent in humans and animal models. Pediatr Surg Int 2011; 27:1255-65. [PMID: 22038274 DOI: 10.1007/s00383-011-2983-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/19/2011] [Indexed: 10/16/2022]
Abstract
Testicular descent is a complex developmental process involving anatomical and hormonal regulation. The gubernaculum undergoes a "swelling reaction" during the transabdominal phase and is mainly under the control of Insulin-Like Peptide 3 (INSL-3) and Mullerian Inhibitory Substance/Anti-Mullerian Hormone (MIS/AMH). The second phase of testicular descent is regulated by androgens and calcitonin gene-related peptide (CGRP) release from the sensory nucleus of the genitofemoral nerve (GFN). In rodents, the active proliferation of the gubernacular tip and cremaster muscle, its rhythmic contraction, as well as the chemotactic gradient provided by the CGRP result in eventual migration of the testis into the scrotum. This review illustrates the structural aspects and hormonal control of cremaster muscle development to better understand the mechanism of testicular descent in normal rodents and humans, compared to diseased rodent models. The analysis showed the cremaster muscle is formed from mesenchymal differentiation of the gubernacular tip and is not a direct passive extension of internal oblique muscle. Cremaster muscle matures slower than other body muscles, and the persistence of immature myogenic proteins seen in cardiac muscle allows rhythmic contraction to guide the testis into the scrotum. Finally, remodelling of the cremaster muscle enables gubernacular eversion. Further understanding of the molecular regulators governing the structural and hormonal changes in the cremaster muscle may lead to new advances in the treatment of undescended testes.
Collapse
Affiliation(s)
- Gabrielle Lie
- Douglas Stephens Surgical Research Unit, Murdoch Childrens Research Institute, Melbourne, Australia
| | | |
Collapse
|
18
|
Churchill JA, Buraundi S, Farmer PJ, Li R, Southwell BR, Hutson JM, Balic A. Gubernaculum as icebreaker: do matrix metalloproteinases in rodent gubernaculum and inguinal fat pad permit testicular descent? J Pediatr Surg 2011; 46:2353-7. [PMID: 22152881 DOI: 10.1016/j.jpedsurg.2011.09.025] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/27/2011] [Accepted: 09/03/2011] [Indexed: 12/21/2022]
Abstract
PURPOSE Cryptorchidism is the most common male congenital abnormality. The rodent gubernaculum steers the testis from abdomen to scrotum postnatally by eversion and migration through the developing inguinal fat pad (IFP). We hypothesize that extracellular matrix remodeling in/around the gubernaculum is necessary for eversion and migration and is permitted by timed IFP maturation and aimed to examine regional development and matrix metalloproteinase (MMP) content. METHODS Embryonic day 19 (E19) and postnatal days 0 and 2 (P0, P2) wild-type Sprague-Dawley rats (n = 10) were prepared for histologic examination (trichrome) and immunohistochemistry (membrane-type MMP-1 [MT1-MMP], MMP2) and analyzed using light/confocal microscopy. RESULTS At E19, IFP contained fibroblasts and immature cells in an extensive collagenous extracellular matrix. Cells in the gubernaculum base were cytoplasmic-MT1-MMP-positive (inactive). At P0, the gubernaculum had everted, and adjacent cells were membranous-MT1-MMP-positive (active). At P2, the gubernaculum was migrating through the IFP, and adjacent cells were membranous-MT1-MMP-positive. Adipocyte maturation began cranially in the IFP and proceeded in a craniocaudal gradient until more uniformly mature at P2. CONCLUSION The MT1-MMP-positive cells may remodel the gubernaculum for eversion and provide the collagenolysis necessary for migration, like an icebreaking ship, through the IFP, which matures to permit migration through collagen-rich tissue. Disruption of these processes may cause cryptorchidism.
Collapse
Affiliation(s)
- James A Churchill
- Murdoch Childrens Research Institute, Parkville, Victoria 3052, Australia
| | | | | | | | | | | | | |
Collapse
|
19
|
Gubernacular development in the mouse is similar to the rat and suggests that the processus vaginalis is derived from the urogenital ridge and is different from the parietal peritoneum. J Pediatr Surg 2011; 46:1804-12. [PMID: 21929994 DOI: 10.1016/j.jpedsurg.2011.02.053] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/07/2011] [Revised: 02/16/2011] [Accepted: 02/17/2011] [Indexed: 11/21/2022]
Abstract
BACKGROUND Gubernacular development and testicular descent have been studied most extensively in rat models, but new transgenic mouse models require a deep understanding of normal mouse development so that results can be extrapolated to the human. We aimed to compare gubernacular anatomy during development in the mouse with that of the rat. METHODS Time-mated mice (C57BL/6) and Sprague-Dawley rats were used to collect male fetuses at embryonic (E) days E13, E14, E15, E17, E18, and E19 and neonates at postnatal (P) days P0 and P2. Fetuses and newborn were processed for serial sections (sagittal, transverse, and coronal) and stained with hematoxylin and eosin, muscle markers (embryonic myosin, desmin), a neuronal marker (Tuj1), a mitotic marker (Ki67), and keratin marker to label epithelium. RESULTS Early development of cremaster in the mouse was related to transversus abdominis muscle, but not internal oblique muscle (as in rats), and forms a monolaminar cremaster layer. There is close association between the regressing inguinal mammary bud and the gubernaculum in the mouse at E13. The peritoneal surface of the processus vaginalis (PV) covering the gubernaculum and epididymis was morphologically distinct from the remaining parietal peritoneum throughout development. CONCLUSIONS Gubernacular development in mouse is similar to that in the rat except for certain structures, such as cremaster muscle. The PV seems to be derived from the surface of the urogenital ridge, separate from the remaining parietal peritoneum. This study suggests that the PV has evolved to aid testicular descent in this species, rather than a nondescript diverticulum of parietal peritoneum.
Collapse
|
20
|
Nation T, Buraundi S, Farmer P, Balic A, Newgreen D, Southwell B, Hutson J. Development of the Gubernaculum During Testicular Descent in the Rat. Anat Rec (Hoboken) 2011; 294:1249-60. [DOI: 10.1002/ar.21393] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2010] [Revised: 02/16/2011] [Accepted: 02/22/2011] [Indexed: 11/10/2022]
|
21
|
The common fetal development of the mammary fat pad and gubernaculum. J Pediatr Surg 2011; 46:378-83. [PMID: 21292091 DOI: 10.1016/j.jpedsurg.2010.11.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2010] [Accepted: 11/04/2010] [Indexed: 11/23/2022]
Abstract
BACKGROUND/AIMS Recent work both from our laboratory and in marsupial models of testicular descent suggests a strong connection between the mammary line and gubernacular migration. This study investigated the relationship between the mammary fat pad (MFP) that underlies the mammary line and the developing gubernaculum by fluorescent immunohistochemistry. METHODS Rats at E17 and E19 were fixed and processed for immunohistochemistry. Sagittal sections of male fetuses were stained with antibodies against androgen receptor (AR), prolyl-4 hydroxylase β, Desmin, activated Notch-1, Jagged-1, and Ki-67. These were analyzed by fluorescent confocal microscopy. RESULTS At E17 and E19, the MFP anlage forms a continuous distribution of fibroblasts passing immediately adjacent the gubernaculum to the future scrotum. Within this exists a distinct subpopulation of fibroblasts expressing AR distributed over the path of inguinoscrotal descent of the gubernaculum. Proliferation and Notch-1 signaling were similar throughout the MFP with differential Notch-1 signaling in the E19 gubernaculum. CONCLUSION This investigation has identified the presence of a distinct AR-expressing subpopulation of MFP fibroblasts over the path of inguinoscrotal descent during the key androgenic programming window of this phase. This unique developmental pattern is consistent with a prime role for the MFP in testicular descent.
Collapse
|
22
|
Abstract
Cryptorchidism is a very common anomaly of the male genitalia, affecting 2%-4% of male infants and is more common in premature infants. There are two separate stages of testicular descent. The first stage occurs at 8-15 weeks' gestation in the human fetus and is characterized by enlargement of the genito-inguinal ligament, or gubernaculum, and regression of the cranial suspensory ligament. The testis remains close to the future inguinal region as the fetal abdomen grows. Leydig cells in the testis produce insulin-like hormone 3, which stimulates the caudal gubernaculum to grow and become thicker. Mullerian inhibiting substance may have a role in the first phase of descent by stimulating the swelling reaction in the gubernaculum. The second phase of testicular descent requires migration of the gubernaculum and testis from the inguinal region to the scrotum, between 25 and 35 weeks' gestation. The genitofemoral nerve releases calcitonin gene-related peptide, a neurotransmitter that provides a chemotactic gradient to guide migration. The exact cause of cyrptorchidism remains elusive. Information is mainly derived from animal studies (especially in rodents), which may not extrapolate to the human setting. These findings, however, do have some similarities among mammalian species. The current recommended timing for orchidopexy is between 6 and 12 months of life in an effort to preserve the spermatogonia--the stem cells for subsequent spermatogenesis. Despite surgical treatment by orchidopexy, the long-term outcome still remains problematic and controversial. Impaired fertility (33% in unilateral cases and 66% in bilateral undescended testes) and a cancer risk 5-10 times greater than normal is observed over time. Further research into the cause and management of undescended testes is necessary.
Collapse
Affiliation(s)
- John M Hutson
- Department of Paediatrics, University of Melbourne, Melbourne, Victoria, Australia.
| | | | | | | |
Collapse
|
23
|
Balic A, Nation T, Buraundi S, Farmer P, Newgreen D, Southwell B, Hutson J. Hidden in plain sight: the mammary line in males may be the missing link regulating inguinoscrotal testicular descent. J Pediatr Surg 2010; 45:414-8; discussion 418. [PMID: 20152364 DOI: 10.1016/j.jpedsurg.2009.10.088] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Accepted: 10/27/2009] [Indexed: 10/19/2022]
Abstract
BACKGROUND/PURPOSE Inguinoscrotal testicular descent is controlled by androgens and the genitofemoral nerve, but the trigger for what makes the gubernaculum become a migratory organ like a limb bud remains unknown. Recent observations in the flutamide-treated rat suggested a link with the mammary line. We aimed, therefore, to reassess histologic anatomy in 2 different rodent models of androgen blockade, the testicular feminisation mouse (TFM) and the flutamide-treated rat. METHODS Neonatal TFM mice and fetal and neonatal rats after pretreatment of dams with an antiandrogen, flutamide (75 mg/kg; sunflower oil; days 16-19), were prepared for histologic analysis of the inguinal region and compared with fetal and neonatal controls. RESULTS Fetal control rats (E15.5 days) showed a mammary bud just outside the future inguinal canal adjacent to the gubernaculum. Neonatal TFM mice showed persistence of the inguinal breast bud supplied by the genitofemoral nerve. Flutamide-treated rats (D2) showed the gubernaculum surrounded by a persisting breast bud. CONCLUSIONS The inguinal mammary line is adjacent to the gubernaculum in fetal rodents, and after androgen blockade, the gubernaculum becomes connected to the breast. The male mammary line, which is hidden in plain sight outside the inguinal canal, is made visible by androgen blockade. It may be the missing link in testicular descent, regulating gubernacular migration.
Collapse
Affiliation(s)
- Adam Balic
- Douglas Stephens Surgical Research, Murdoch Childrens Research Institute, Flemington Road, Parkville Victoria, Australia
| | | | | | | | | | | | | |
Collapse
|