Immunohistochemical Evaluation of the Expression of Anti-Müllerian Hormone in Mature, Immature and Neoplastic Canine Sertoli Cells

Preliminary Evidence of the Possible Roles of the Ferritinophagy-Iron Uptake Axis in Canine Testicular Cancer

Iron is a key element in spermatogenesis; its metabolic pathway in the testis is strictly regulated. Alterations in iron metabolism are linked to various diseases, including cancer, and changes in iron metabolism-related proteins have been observed in multiple human, mouse and canine tumors. There is limited knowledge about iron metabolism in canine non-neoplastic and neoplastic testes. This study aimed to explore the immunohistochemical expression of molecules involved in iron uptake and storage [Transferrin Receptor 1 (TfR1), ferritin (FTH1), nuclear receptor coactivator 4 (NCOA4)] and PCNA in canine non-neoplastic and neoplastic testicular samples. Non-neoplastic testes showed moderate TfR1 expression in developing germ cells and Sertoli cells, high NCOA4 cytoplasmic immunostaining in the Sertoli cells and occasional cytoplasmic immunopositivity for FTH1 in the spermatogonia and Sertoli cells. In contrast, Leydig cell tumors (LCTs) and Diffuse Type Seminoma (DSEM) exhibited increased expression of TfR1, along with higher PCNA expression, suggesting a higher iron need for proliferation. Intratubular Type Seminoma (ITSEM) showed a higher FTH1 expression, indicating greater iron storage, while the increased NCOA4 expression in the LCTs and DSEM suggested ferritinophagy to release iron for proliferation. Sertoli cell tumors (SCTs) showed only NCOA4 expression. These preliminary findings highlight potential molecular targets for developing new anti-neoplastic treatments in canine testicular tumors.

Physiological Anti-Müllerian Hormone Concentrations in Male and Female Dogs and Cats before and around Puberty

In recent years several studies established the diagnostic value of anti-Müllerian hormone (AMH) in companion animals. However, less is known about physiological AMH concentrations in young individuals highlighting the necessity to apply the diagnostic findings to this group. The aim of this study was to determine the AMH values of healthy male and female dogs between the age of 8 and 48 weeks, tomcats under 8 weeks and up to 48 weeks of age and queens between 2 to 12 weeks of age. In total, 96 blood samples were collected. Anti-Müllerian hormone was measured in all samples and testosterone was measured in the oldest age group of the males in both species. The hormones were analyzed using a human based chemiluminescence immune assay. Overall, AMH concentrations were higher in males than in females (p < 0.001). According to the AMH concentration there was no difference in males, but queens had significant higher AMH concentrations than bitches (p < 0.001). AMH remained high in males up to week 24 and decreased significantly thereafter (tomcats: p = 0.015; male dogs: p = 0.013), which correlated with an increase in testosterone levels for male dogs only. In bitches, AMH remained below the detection limit until the week 16 and slightly increased subsequently. In queens, AMH was detectable from the beginning with a significant increase in the older age group (p = 0.003). Half of the cats in the older age group even approached the chemiluminescence immune assay's upper limit. The results show that female cats secrete AMH much earlier than female dogs in which AMH secretion begins just shortly before the start of the puberty. In the male animals, the decrease in AMH concentration around puberty was similar in dogs and cats, but a correlation with the increase of testosterone was only observed in dogs. Further research is required to determine the origin of the high AMH concentrations in female kittens and the lack of correlation between testosterone and AMH concentrations in male kittens.

Cryptorchidism and testicular cancer in the dog: unresolved questions and challenges in translating insights from human studies†

Cryptorchidism, the failure of one or both testes to descend into the scrotum, and testicular cancer show a strong correlation in both dogs and humans. Yet, long-standing medical debates persist about whether the location of undescended testes directly causes testicular cancer in humans or if both conditions stem from a common origin. Although testicular cancer is a prevalent disease in dogs, even less is known about its cause and correlation with testicular descent in this species. This review investigates the relation between these two disorders in dogs, drawing insights from human studies, and examines key biomarkers identified thus far. In addition, it explores potential causal links, including the impact of temperature on maturing testicular cells and a potential shared genetic origin. Notably, this literature review reveals significant differences between men and dogs in reproductive development, histological and molecular features of testicular tumors, and the prevalence of specific tumor types, such as Sertoli cell tumors in cryptorchid dogs and germ cell tumors in humans. These disparities caution against using dogs as models for human testicular cancer research and underscore the limitations when drawing comparisons between species. The paper concludes by suggesting specific research initiatives to enhance our understanding of the complex interplay between cryptorchidism and testicular cancer in dogs.

Half-life of serum anti-Müllerian hormone and changes after gonadectomy in adult female and male dogs with normal and abnormal gonads

Anti-Müllerian hormone (AMH) is a biomarker for the presence of gonadal tissue. Changes in serum AMH after gonadectomy are not well established, and its serum half-life is unknown in dogs. We measured serum AMH with a validated electro-chemiluminescent immunoassay in adult female (n = 12) and male (n = 7) dogs with normal gonads, as well as in dogs with gonadal pathology (ovarian remnant syndrome, ORS n = 3, testicular tumor [Leydig cell, Sertoli cell, seminoma] n = 3, unilateral abdominal cryptorchid n = 4) on the day of gonadectomy (D0), and on D3, D7, D14 (females and males), and D21, D28 (males only). Males had higher AMH concentrations than females independent of gonadal status (P < 0.001). Dogs with ORS had lower initial AMH (0.45 ± 0.43 ng/ml) than bitches with normal gonads (1.16 ± 0.44 ng/ml; P = 0.027). Cryptorchid dogs had higher initial concentrations (80.57 ± 52.81 ng/ml) than males with normal gonads (7.92 ± 2.45 ng/ml; P = 0.004), and those with testicular tumors (18.63 ± 5.04 ng/ml) were intermediate (P ≥ 0.250). AMH decreased over time (P ≤ 0.012) and was 0.01-0.04 ng/ml by D14 in females and 0.02-0.12 ng/ml by D28 in males. Serum half-life in the whole study population was 2.85 ± 0.51 days and did not differ between groups. In conclusion, serum AMH can differentiate between intact and gonadectomized status of adult dogs by 14 days after ovario(hyster)ectomy in females and by 28 days after surgical castration in males.

Anti-Müllerian hormone levels in serum and testes of male dogs: relations with neuter status and bilateral abdominal cryptorchidism

Anti-Müllerian hormone (AMH) analysis has contributed to new information in the reproductive endocrinology of domestic animals, due to clinically available diagnostic tools. An accurate and rapid diagnostic method to distinguish between neutered and bilateral abdominal cryptorchid dogs is needed in veterinary practice. Therefore, this study uses an enzyme-linked immunosorbent assay to evaluate the clinical relevance of AMH analysis in peripheral blood as a diagnostic tool for dogs with suspected bilateral abdominal cryptorchidism. The possible alteration of the AMH localization in testicular tissue caused by this pathologic condition was also investigated using immunohistochemistry. Male dogs were divided into three groups of healthy intact (n = 14), healthy castrated (n = 14), and bilateral abdominal cryptorchid (n = 14) dogs. The results demonstrated a higher level of serum AMH in the cryptorchid group compared to the intact group (P < 0.01), while serum AMH levels of all castrated dogs were below the limit of detection (<0.05 ng/mL). Moreover, the percentage of positive AMH immunostaining of the intact group was less than that of the cryptorchid group (P < 0.01). A significantly positive correlation was found between serum AMH concentration and localization in testicular tissues (r = 0.93, P < 0.01). Our findings suggest that AMH levels in the peripheral blood could be used as an alternative and rapid screening method for detecting dogs with abdominal cryptorchidism.

[Diagnostic utility of the anti-Mullerian hormone in companion animals]

The anti-Mullerian hormone is a glycoprotein secreted by Sertoli cells in males and granulosa cells in females. The initial identification of this hormone in canine and feline serum was achieved in 2011. Meanwhile, a variety of studies have demonstrated its clinical significance as a tool in the endocrine diagnosis. This review summarizes the current knowledge about anti-Mullerian hormone in small animal reproduction and describes future opportunities for its diagnostic usage.

Serum Anti-Müllerian Hormone: A Potential Semen Quality Biomarker in Stud Dogs?

Anti-Müllerian hormone (AMH) has been suggested to be involved in spermatogenesis. The aim of this study was to investigate the relationship between blood serum AMH concentration and semen quality in dogs. Moreover, this study sought to find the optimal cut-off point value of serum AMH with the greatest sensitivity and specificity to predict semen quality. Forty-five clinically healthy dogs were included in the study and their age as well as the following semen parameters were determined and correlated to serum AMH concentration: total sperm output, normal morphology, plasma membrane integrity, total motility, progressive motility, and velocity parameters. Statistical analysis for correlations were performed using Spearman’s correlation coefficients. Moderate negative associations were found between serum AMH and semen total motility (r = −0.38, p = 0.01), progressive motility (r = −0.36, p = 0.01), and normal morphology (r = −0.36, p= 0.02). Based on these associations, an AMH concentration of 5.54 µg/L was found to be the optimal cut-off point value to obtain the greatest summation of sensitivity (86%) and specificity (63%) to predict semen quality. The serum AMH assay may therefore be a potential hormonal marker to predict which dogs would require further semen analysis. Future research is however needed to confirm these preliminary results.

Sertoli, Leydig, and Spermatogonial Cells’ Specific Gene and Protein Expressions as Dog Testes Evolve from Immature into Mature States

Sertoli, Leydig, and spermatogonial cells proliferate and differentiate from birth to puberty and then stay stable in adulthood. We hypothesized that expressions of spermatogenesis-associated genes are not enhanced with a mere increase of these cells’ numbers. To accept this postulation, we investigated the abundances of Sertoli cell-specific FSHR and AMH, Leydig cell-specific LHR and INSL3, and spermatogonia-specific THY1 and CDH1 markers in immature and mature canine testis. Four biological replicates of immature and mature testes were processed, and RT-PCR was performed to elucidate the cells’ specific markers. The data were analyzed by ANOVA, using the 2−∆∆Ct method to ascertain differences in mRNA expressions. In addition, Western blot and IHC were performed. Gene expressions of all the studied cells’ specific markers were down-regulated (p < 0.05) in adult testis compared with immature testis. Western blot and immunohistochemistry showed the presence of these proteins in the testis. Protein expressions were greater in immature testis compared with mature testis (p < 0.05). Despite the obvious expansion of these cells’ numbers from immature to adult testis, the cells’ specific markers were not enriched in mature testis compared with immature dog testis. The results support the postulation that the gene expressions do not directly correlate with the increase of the cell numbers during post-natal development but changes in gene expressions show functional significance.

Immunohistochemical insights into a hidden pathology: Canine cryptorchidism

Cryptorchidism is a common disorder in the canine population with some aspects still unclear. Although the bilateral condition is known to lead to fertility problems and predisposition to testicular cancer, the neoplastic risk for scrotal testis in unilateral cryptorchid dog is controversial. Therefore, the therapeutic approach to the canine unilateral cryptorchid is arbitrary so far. This study aimed to investigate precancerous testicular lesions, such as immaturity and atrophy, and compare them in scrotal and undescended testes using an in-depth diagnostic analysis based on immunophenotypic patterns. With this purpose, 26 adult male dogs of different ages and breeds, affected by unilateral or bilateral cryptorchidism were enrolled. After surgical removal, testes were examined immunohistochemically to assess their positivity for specific markers of the canine foetal/neonatal period, that is vimentin (VIM), cytokeratin (CK), desmin (DES), inhibin-α (INH), and anti-Müllerian hormone (AMH) in Sertoli cells, and placental alkaline phosphatase (PLAP) in germ cells. Except for the ubiquitous VIM, all the markers were more expressed in neoplastic gonads compared to healthy ones (P < 0.05). Similarly, testes detected with Sertoli cell-only tubules as well as with Sertoli cells hyperplasia showed higher expression than gonads without such alterations for CK, DES, AMH and PLAP, and for CK and DES, respectively (P < 0.05). The same trend was observed in undescended respect to scrotal testes even though their positivity was significant only for DES, INH and AMH (P < 0.05). Immunohistochemical positivity found in scrotal testes of unilateral cryptorchid dogs, even in absence of detectable anatomical abnormalities, was suggestive of precancerous lesions. Despite the limited sample size, this study could help to clarify the predisposition to neoplastic development in normally descended testes. These markers expression in adult life could allow identifying the early stages of the testicular carcinogenesis process besides suggesting a precautionary bilateral surgical approach in unilateral cryptorchid dogs.

Anti-Müllerian hormone, testosterone, and insulin-like peptide 3 as biomarkers of Sertoli and Leydig cell function during deslorelin-induced testicular downregulation in the dog

The role of anti-Müllerian hormone (AMH) and insulin-like peptide 3 (INSL3) in male infertility is not fully understood. We used the downregulated testis as a model of gonadotropin-dependent infertility. Serum testosterone and AMH concentrations were studied in five adult male Beagles implanted (day 0) with 4.7 mg deslorelin (Suprelorin®, Virbac) (DES group). Testicular expression of LH receptor (LHR) and androgen receptor (AR), AMH, type 2 AMH receptor (AMHR2), INSL3 and its receptor (RXFP2) was evaluated 112 days (16 weeks) after deslorelin treatment by qPCR and immunohistochemistry, and compared to untreated adult (CON, n = 6) and prepubertal (PRE, n = 8) dogs. Serum testosterone concentration decreased significantly by the onset of aspermia on study day 14 (four dogs) or day 21 (one dog), and was baseline on day 105 (week 15). In contrast, serum AMH started to increase only after the onset of aspermia and reached the maximum detectable concentration of the assay by day 49-105 in individual dogs. Testicular LHR gene expression in DES was lower than in CON and PRE (P < 0.0001), while AR gene expression in DES was similar to CON and significantly higher than PRE (P < 0.0001). Testicular AMH expression in DES was intermediate compared to the lowest mRNA levels found in CON and the highest in PRE (P ≤ 0.006). AMHR2 gene expression was similar between groups. AMH protein was detected in Sertoli cells only, while AMHR2 immunoreactivity was principally detected in Leydig cells which appeared to be increased in DES. INSL3 and RXFP2 gene expression was significantly downregulated in the DES testis along with noticeably weak Leydig cell immunosignals compared to CON. In conclusion, deslorelin treatment caused testicular LH insensitivity without affecting androgen sensitivity, and de-differentiation of Sertoli and Leydig cells. In DES, upregulation of the AMH-AMHR2 feed-back loop and downregulation of the INSL3-RXFP2 feed-forward loop are paracrine-autocrine mechanisms that may additionally regulate testosterone production independent of gonadotropins. Our results support AMH and INSL3 as unique biomarkers and paracrine-autocrine regulators of testis function involved in the intimate interplay between Sertoli and Leydig cells.

Clinical Applications of Serum Anti-Müllerian Hormone Measurements in Both Males and Females: An Update

Infertility is one of the most common non-communicable diseases, affecting both men and women equally. Ovarian reserve, the number of primordial follicles in the ovaries is believed to be the most important determinants for female fertility. Anti-Müllerian hormone (AMH) secreted from granulosa cells of growing follicles is recognized as the most important biomarker for ovarian reserve. Ovarian reserve models have been developed using AMH and other hormonal indicators, thus childbearing plans and reproductive choices could be arranged by women. In assisted reproductive technology cycles, measurement of AMH helps to predict ovarian response and guide recombinant follicle-stimulating hormone dosing in women. Serum AMH level is increasingly being recognized as a potential surrogate marker for polycystic ovarian morphology, one of the criteria for diagnosis of polycystic ovarian syndrome. AMH is also secreted by Sertoli cells of testes in men, and AMH measurements in the prediction of surgical sperm recovery rate in men have also been investigated. AMH levels are significantly higher in boys than in girls before puberty. Therefore, serum levels of AMH in combination with testosterone is used for the differential diagnosis of disorders of sex development, anorchia, non-obstructive azoospermia, and persistent Müllerian duct syndrome. Recently, serum AMH measurements have also been used in fertility preservation programs in oncofertility, screening for granulosa cell tumors, and prediction of menopause applications. In this review, we will focus on clinical application of AMH in fertility assessments for healthy men and women, as well as for cancer patients.

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Anti-Müllerian hormone (AMH) plays a key role in models assessing ovarian reserve

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AMH is used for the differential diagnosis of disorders of sex development

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AMH provides a molecular marker for related fertility and infertility disorders

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An international standard will aid in the development of various AMH assays

Senescence and adiponectin signaling - Studies in canine testis

BACKGROUND

The meaning of senescence for tissue physiological and pathological conditions is poorly known. Based on initial reports especially proteins and mechanisms that regulate this process are necessary to be determinate.

METHODS

The main aim of the study was to investigate the presence of senescent cells in canine testicular tissue (mixed breed testes; n = 60) in relation to adiponectin signaling. In detail, new information on the senescence cell number, as well as senescence and adiponectin signaling mechanisms in cryptorchid and germ cell tumor testes were provided with the use of immunohistochemical and colorimetric analyses.

RESULTS

Comparison of immunohistochemical results, in cryptorchid and tumor testes revealed increased number of senescent cells (p16 and γH2AX markers). Increased expression of adiponectin and adiponectin receptor 1, as well as extracellular signal-activated kinase (ERK1/2) in pathological testes were detected. In addition, decreased cholesterol and increased testosterone levels in tumor testis were found.

CONCLUSION

The present study is the first to demonstrate the presence as well as the differences that exist in senecent cell number in mixed breed dog testes with cryptorchidism and germ cell tumor. Altered expression of adiponectin signaling and ERK1/2 signaling pathways together with altered cholesterol and testosterone levels reflect important senescence role in disturbed functions of canine testis. Moreover, the application of studied here senescence regulating molecules for detection and prevention against pathologies of the male gonad should be furtherly considered.

Progesterone receptor membrane component 1 (PGRMC1) expression in canine mammary tumors: A preliminary study

Canine mammary tumors (CMT) represent the most common neoplasms in female dogs and their diagnosis and classification relies on histopathological examination. Recently, PGRMC1 has been considered to be a putative biomarker for diagnosis and prognosis in many human cancers as it is expressed in a wide variety of tumors. This study represents the first description of PGRMC1 expression in CMT. PGRMC1 expression was initially assessed by immunohistochemistry in healthy or hyperplastic tissues and in four major histopathological types of CMT: simple and complex adenomas and carcinomas. PGRMC1 staining was represented by a scoring system that considered the percentage of positive cells and staining intensity. PGRMC1 expression was defined as either weak, moderate or strong. In healthy and hyperplastic tissues almost 100% of the epithelial cells stained intensely for PGRMC1. Adenomas showed similar features but with a more variable intensity. In tubular areas of adenocarcinomas, a lower percentage of epithelial cells (30-60%) stained for PGRMC1 with a weak intensity. Both the percentage of cells and intensity of PGRMC1 staining became progressively negative in the solid parts of the tumor. Western blot analysis of healthy and neoplastic mammary tissue (carcinomas samples) revealed the presence of the 25 kDa PGRMC1 band in both types of tissue, while the 50 kDa form was mainly detected in the healthy counterpart. This study reveals that PGRMC1 is expressed in CMT and its expression pattern changes depending on the pattern of growth of CMT. Further studies are now needed to determine PGRMC1's putative role and usefulness for typing and prognosis of different CMT subtypes.

Investigation of interference from canine anti-mouse antibodies in hormone immunoassays

BACKGROUND

Canine anti-mouse antibodies are a potential source of immunoassay interference, but erroneous immunoassay results are not always easily identifiable. Anti-Müllerian hormone (AMH) is a marker for the presence of gonads in dogs, but elevated AMH concentrations in neutered dogs could also be caused by antibody interference. For other assays, a discrepant result obtained after antibody precipitation might indicate antibody interference.

OBJECTIVES

We aimed to evaluate if canine anti-mouse antibodies are a source of erroneous results in the AMH assay and if antibody precipitation with polyethylene glycol (PEG) is a useful tool for detecting antibody interference in a variety of immunoassays used in the veterinary clinical laboratory.

METHODS

Twenty-nine positive and 25 negative samples for anti-mouse antibodies were analyzed for AMH, canine total thyroxine (TT₄ ), canine thyroid-stimulating hormone (TSH) and progesterone before and after treatment with PEG. Results that differed by more than four SDs from the intra-assay coefficients of variation were considered discrepant. Elevated AMH concentrations in neutered dogs with anti-mouse antibodies and no visible gonads present were considered evidence of interference.

RESULTS

Evidence of antibody interference was found in two samples analyzed for AMH. The presence of anti-mouse antibodies did not lead to a higher proportion of discrepant results after PEG treatment for any of the immunoassays. The overall incidence of discrepant results for healthy controls was very high (73%).

CONCLUSIONS

Canine anti-mouse antibodies are a source of erroneous AMH results. Antibody precipitation with PEG is not a useful tool for detecting interference caused by such antibodies.

Evaluation of Canine Sperm and Management of Semen Disorders

Semen evaluation of the male dog is a critical step in any canine infertility work-up. Assessment of total sperm count, sperm viability, and sperm morphology are the mainstay of breeding soundness evaluation. Adjunct tests, such as ultrasonography and serum hormone levels, can aid in diagnosis. Pharmacologic treatments, dietary supplements, and management practices may help improve breeding success in subfertile dogs. This article discusses a clinically practical approach to assessing sperm abnormalities and fertility in male dogs.

Effect of age and castration on serum anti-Müllerian hormone concentration in male alpacas

The synthesis of anti-Müllerian Hormone (AMH) by the Sertoli cells in males is crucial for sexual differentiation. There are no studies on AMH in Camelids. The objectives of this research were to 1) compare AMH serum concentrations in prepubertal and adult male alpacas and 2) determine the effect of castration on these concentrations in adult males to provide a validation of a commercial AMH test in alpacas. Serum samples were obtained from 15 prepubertal animals (5 for each age groups of 6, 7 and 8 months) and from 5 adult males (age 5-9 years), pre- and 24 h post-castration. AMH was determined with a quantitative ELISA according to the manufacture's instructions. There was not significant difference (P < 0.05) in AMH level (pg/ml) between pre-pubertal (549.9 ± 120.8, 789.4 ± 172.3, 597.5 ± 177.3 for ages 4, 7, and 8 months, respectively) and adult alpacas (938.7 ± 175.9). In adult males, AMH concentration decreased significantly following castration (P < 0.05) (938.7 ± 383.5 pg/ml) pre-castration, and 222.1 ± 116.5 pg/ml) after castration). There was a positive correlation between testosterone levels and AMH. In conclusion, the quantitative assay used is a reliable test to determine AMH in alpacas. The AMH level in prepubertal and adult alpacas appear to not differ, contrarily from other mammals, this requires further investigation. The decrease in serum AMH concentrations after castration suggests that measurement of this hormone can be used to diagnose bilateral cryptorchid or hemicastrated unilateral cryptorchid animals in this species.

Prevalence of the AMHR2 mutation in Miniature Schnauzers and genetic investigation of a Belgian Malinois with persistent Müllerian duct syndrome

Persistent Müllerian duct syndrome (PMDS) is a sex-limited disorder in which males develop portions of the female reproductive tract. Important consequences of PMDS are cryptorchidism and its sequelae of infertility and increased risk of testicular cancer. Anti-Müllerian hormone (AMH) and its receptor (AMHR2) induce the regression of the Müllerian ducts in male embryos. In Miniature Schnauzer dogs, the genetic basis has been identified as an autosomal recessive nonsense mutation in AMHR2, but the allele frequency of the mutation is unknown. Thus, the primary objective of this study was to estimate the prevalence of the AMHR2 mutation in North American Miniature Schnauzers, in order to ascertain the value of genetic testing in this breed. An additional objective was to determine whether mutations in AMH or AMHR2 were responsible for PMDS in a Belgian Malinois; this would aid development of a genetic test for the Belgian Malinois breed. Genomic DNA from 216 Miniature Schnauzers (including one known PMDS case) was genotyped for the AMHR2 mutation, and DNA from a single PMDS-affected Belgian Malinois was sequenced for all coding exons of AMH and AMHR2. The Miniature Schnauzer cohort had an AMHR2 mutation allele frequency of 0.16 and a carrier genotypic frequency of 0.27. The genetic basis for PMDS in the Belgian Malinois was not determined, as no coding or splicing mutations were identified in either AMH or AMHR2. These findings support a benefit to AMHR2 mutation testing Miniature Schnauzers used for breeding or with cryptorchidism.

Immunophenotyping of Rabbit Testicular Germ and Sertoli Cells Across Maturational Stages

During testicular maturation, both Sertoli cells (SCs) and germ cells (GCs) switch from an immature to a mature immunophenotype. The reexpression of markers of immaturity in adults has been reported in cancer and in other testicular pathologies, in men as well as in animal species. Naturally affected with testicular cancer, rabbits have long been used in human reproductive research, but reports on the expression of testicular cell markers in this species are few and data about the immunophenotype of normal postnatal SCs and GCs are lacking. The aim of this study was to investigate the immunophenotype of SCs and GCs in the rabbit, from neonatal to adult age, using the antibodies anti-Müllerian hormone (AMH), vimentin (VIM), CKAE1/AE3 (cytokeratins [CKs]), desmin (DES), inhibin alpha (INH-α), placental alkaline phosphatase (PLAP), and periodic acid-Schiff (PAS) staining. In SCs, VIM was constantly expressed, and AMH and CKs expression was limited to neonatal and prepubertal age, whereas DES, INH-α, PLAP, and PAS were constantly negative. GCs were negatively stained for PLAP, PAS, and for the other markers. Results revealed analogies with human testicular immunophenotype, suggesting that rabbits could represent a potential experimental model for the study of human testicular pathology.

Anti-Müllerian hormone: a potentially useful biomarker for the diagnosis of canine Sertoli cell tumours

Background

Testicular tumours are common in dogs and in many cases do not give rise to clinical signs. In other cases, signs of feminization, hyperpigmentation or alopecia may be observed, most commonly associated with Sertoli cell tumours (SCT). Although these signs are often associated with elevated concentrations of oestradiol, analysis of oestradiol may give inconclusive results due to large variations among individuals. Other biomarkers are therefore needed. Anti-Müllerian hormone (AMH) is expressed by the Sertoli cell. In humans, AMH has been shown to be a specific marker of Sertoli cell origin in gonadal tumours. Using immunohistochemistry, AMH has been shown to be a useful marker of immature and neoplastic Sertoli cells in dogs. The aim of the present study was to evaluate the clinical relevance of AMH analysis in peripheral blood in the diagnostic workup of dogs with suspected testicular tumours.

Results

Blood was collected from 20 dogs with a palpable testicular mass and from 27 healthy controls. Serum was analysed for oestradiol-17β using a RIA and for AMH using an ELISA. The Mann–Whitney U test was used to compare hormone concentrations between different groups.

All control dogs had AMH concentrations ≤ 10 ng/mL, except one outlier that had a concentration of 43 ng/mL. Six dogs with SCT or mixed tumours containing SCT had AMH concentrations higher than 22 ng/mL, significantly higher than AMH concentrations in control dogs (P = 0.0004). Concentrations between 10 and 22 ng/mL were found in about half of the dogs with non-neoplastic testicular pathologies or with testicular tumours other than SCTs. Age did not significantly affect concentrations of AMH in the control dogs.

Conclusion

AMH was shown to be a promising biomarker for the diagnosis of Sertoli cell tumours in dogs.