Histopathology of the tubuli recti at the start of experimental autoimmune orchitis in mice

Microenvironment for spermatogenesis and sperm maturation

The male reproductive system consists of testes, a series of ducts connecting the testes to the external urethral orifice, accessory sex glands, and the penis. Spermatogonial stem cells differentiate and mature in testes and epididymides, and spermatozoa are ejaculated with exocrine fluids secreted by accessory sex glands. Many studies have clarified the detailed structure and function of the male reproductive system, and have shown that various biologic controls, including genomics, epigenetics, and the neuroendocrine-immune system regulate proliferation, differentiation, and maturation of germ cells. In other words (1) genetic deletion or abnormalities, (2) aberration of DNA methylation and histone modifications, as well as small RNA dysfunction, and (3) neuroendocrine-immune disorders are involved in functional failure of the male reproductive system. In this article, we review these three factors for germ cell microcircumstance, especially focused on the immunoendocrine environment. In particular, the relation between factors protecting germ cells with strong auto-immunogenicity and opposite factors compromising this protection are discussed. Reductions in sperm count, concentration, and semen quality are serious problems in developed countries, although the causes are complex and remain unclear. The accumulation of basic knowledge regarding the structure, function, and regulation of the male reproductive system under various experimental conditions will be important to resolve these problems.

Insights into differentiation and function of the transition region between the seminiferous tubule and rete testis

Seminiferous tubules physically connect to the rete testis through short segments called the transition region (TR). During fetal development, this specialized junction is considered the initial site where testis cords begin to form and to grow in length well beyond birth and into adulthood and form convoluted tubular cores. Mitotic activity of the Sertoli cell, the somatic cell of the epithelium, ceases before puberty, but modified Sertoli cells in the TR remain immature and capable of proliferation. This review presents what is known about this specialized region of the testis, with an emphasis on the morphological, molecular and physiological features, which support the hypothesis that this short region of epithelial transition serves as a specialized niche for undifferentiated Sertoli cells and spermatogonial stem cells. Also, the region is populated by an elevated number of immune cells, suggesting an important activity in monitoring and responding to any leakage of autoantigens, as sperm enter the rete testis. Several structure/function characteristics of the transition region are discussed and compared across species.

Dkk1 involvement and its potential as a biomarker in pancreatic ductal adenocarcinoma

Dickkopf-1 (Dkk1)'s dysregulation has been implicated in the pathogenesis of a variety of cancers. It is part of the Dkk family of proteins that includes Dkk2, Dkk3 and Dkk4. This family of secreted proteins shares similar conserved cysteine domains and inhibits the Wnt/b-catenin pathway by causing proteasomal B-catenin degradation, inducing apoptosis, and preventing cell proliferation. Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer mortality in the United States due to the late stage of diagnosis and the limited effectiveness of current therapy. Dkk1 is found increased in PADC patients' specimens and serum. Dkk1 can be a promising biomarker specific to PDAC, which has the potential to increase PDAC survival rates through improving early stage detection and monitoring progression compared to current biomarker gold standards. In addition, recent studies suggest that Dkk1 could be an excellent target for cancer immunotherapy. Interestingly, Dkk1-CKAP4-PI3K/AKT signal pathway also plays role in pancreatic cancer cell proliferation. In this review, we present the multiple mechanisms of Dkk1 in PDAC studied thus far and explore its function, regulation, and clinical applications in gynecological cancers including pancreatic ductal adenocarcinoma (PDAC), breast, ovarian, cervical, and endometrial cancer. Further research into Dkk1's mechanism and use as a diagnostic tool, alone or in combination with other biomarkers, could prove clinically useful for better understanding the pathology of PDAC and improving its early detection and treatment.

Only a small population of adult Sertoli cells actively proliferates in culture

Adult mammalian Sertoli cells (SCs) have been considered to be quiescent terminal differentiated cells for many years, but recently, proliferation of adult SCs was demonstrated in vitro and in vivo. We further examined mouse SC behavior in culture and found that there are two populations of adult SCs. The first population is SCs from seminiferous tubules that hardly proliferate in vitro. The second population is small and consists of SCs with atypical nuclear morphology from the terminal segments of seminiferous tubules, a transitional zone (TZ). TZ SCs multiply in culture and form colonies, display mixture of mature and immature SC characteristics, and generate cord-like structures in a collagen matrix. The specific features of TZ SCs are ACTA2 expression in vitro and DMRT1 low levels in vivo and in vitro. Although the in vivo function of TZ SCs still remains unclear, this finding has significant implications for our understanding of SC differentiation and functioning in adult mammals.

Contribution of IL-12/IL-35 common subunit p35 to maintaining the testicular immune privilege

The testis is an organ with immune privilege. The comprehensive blood–testis barrier formed by Sertoli cells protects autoimmunogenic spermatozoa and spermatids from attack by the body’s immune system. The interleukin (IL)-6/IL-12 family cytokines IL-12 (p35/p40), IL-23 (p19/p40), IL-27 (p28/Epstein-Barr virus−induced gene 3 [EBI3]), and IL-35 (p35/EBI3) play critical roles in the regulation of various immune responses, but their roles in testicular immune privilege are not well understood. In the present study, we investigated whether these cytokines are expressed in the testes and whether they function in the testicular immune privilege by using mice deficient in their subunits. Expression of EBI3 was markedly increased at both mRNA and protein levels in the testes of 10- or 12-week-old wild-type mice as compared with levels in 2-week-old mice, whereas the mRNA expression of p40 was markedly decreased and that of p35 was conserved between these two groups. Lack of EBI3, p35, and IL-12 receptor β2 caused enhanced infiltration of lymphocytes into the testicular interstitium, with increased interferon-γ expression in the testes and autoantibody production against mainly acrosomal regions of spermatids. Spermatogenic disturbance was more frequently observed in the seminiferous tubules, especially when surrounded by infiltrating lymphocytes, of these deficient mice than in those of wild-type mice. In particular, p35-deficient mice showed the most severe spermatogenic disturbance. Immunohistochemical analyses revealed that endothelial cells and peritubular cells in the interstitium were highly positive for p35 at both ages, and CD163⁺ resident macrophages positive for p35 and EBI3, possibly producing IL-35, were also detected in the interstitium of 12-week-old mice but not those of 2-week-old mice. These results suggest that p35 helps in maintaining the testicular immune privilege, in part in an IL-35-dependent manner.

Chronological changes of delayed-type hypersensitivity in mice immunised with testicular germ cells alone

Experimental autoimmune orchitis (EAO), comprising a breakdown of the testicular immune privilege, is one of the models of immunological male infertility. EAO is characterised by CD4 + T-cell-dependent lymphocytic inflammation and augmented delayed-type hypersensitivity (DTH) against testicular antigens. We previously established an EAO model in mice by immunisation with viable syngeneic testicular germ cells (TGC) alone. However, the sequential change of DTH during development of this EAO has not been analysed yet. In this study, the DTH response during TGC-induced EAO was investigated by the injection of syngeneic TGC protein into the ears of mice. The results showed that a significant DTH response was observed on injection of 20 μg TGC protein, but not on that of 0.2 or 2 μg TGC protein. Also, the level of the DTH response to 20 μg TGC protein was highly relevant to the pathology of EAO development. These results indicate that the DTH response on injection of 20 μg TGC protein into the ears of mice is effective for predicting the pathology of EAO development.

Orchestrated leukocyte recruitment to immune-privileged sites: absolute barriers versus educational gates

Complex barriers separate immune-privileged tissues from the circulation. Here, we propose that cell entry to immune-privileged sites through barriers composed of tight junction-interconnected endothelium is associated with destructive inflammation, whereas border structures comprised of fenestrated vasculature enveloped by tightly regulated epithelium serve as active and selective immune-skewing gates in the steady state. Based on emerging knowledge of the central nervous system and information from other immune-privileged sites, we propose that these sites are endowed either with absolute endothelial-based barriers and epithelial gates that enable selective and educative transfer of trafficking leukocytes or with selective epithelial gates only.

Intratesticular expression of mRNAs of both interferon γ and tumor necrosis factor α is significantly increased in experimental autoimmune orchitis in mice

Experimental autoimmune orchitis (EAO) is one of the models of immunological male infertility. Murine EAO is CD4+T cell-dependent and classically induced by immunization with a testicular homogenate and adjuvants. We previously established that immunization with viable syngeneic testicular germ cells (TGC) can also induce murine EAO with no use of any adjuvant. Analyses of this EAO model have already revealed that cultured spleen cells of immunized mice secreted interferon (IFN)-γ and that treatment of the immunized mice with anti-IFN-γ monoclonal antibodies significantly suppressed the EAO. It is known that both IFN-γ and tumor necrosis factor (TNF)-α are representative cytokines of Th1 cells and exhibit local toxicity toward the seminiferous epithelium in vivo. However, changes in these two cytokines in EAO-affected testes have not yet been investigated. Therefore, in the present study, we investigated the expression of intratesticular IFN-γ and TNF- α mRNAs in TGC-induced EAO using real-time RT-PCR. The results demonstrated that the intratesticular mRNAs for both IFN-γ and TNF-α significantly increased, while other cytokines such as IL-1α, IL-1β, IL-6 and TGF-β did not show dramatic changes in the immunized mice. These results suggest that secretion of significant amounts of IFN-γ and TNF-α in situ contributes to the spermatogenic disturbance in EAO.

Hyposensitization therapy with autologous semen in two Dutch caucasian males: beneficial effects in Postorgasmic Illness Syndrome (POIS; Part 2)

INTRODUCTION

Postorgasmic illness syndrome (POIS) is a post-ejaculatory complex of local and/or systemic symptoms that nearly always occurs within seconds, minutes, or hours post-masturbation, coitus, or spontaneous ejaculation. Recent data suggest an autoimmunogenic/allergic underlying mechanism.

AIM

To treat males with POIS by hyposensitization with their own semen (autologous semen).

METHODS

Two males suffering from POIS, of which one male with coincidental lifelong premature ejaculation (PE) were investigated. Based on their local and systemic symptoms including a positive dermatologic reaction after skin-prick testing with autologous semen, auto-allergy to semen was likely an underlying mechanism. A hyposensitization program was initiated, including multiple subcutaneous (SC) injections with autologous semen, initially at 2 weeks intervals in the first year and gradually at 4 weeks intervals in the second and third year. From initial semen dilutions of 1 on 40,000 and 1 on 20,000, the titers were gradually increased to 1 on 20 and 1 to 280, respectively.

MAIN OUTCOME MEASURES

Evaluation with a dedicated questionnaire about severity of POIS symptoms and specialized interviews on self-perceived intravaginal ejaculation latency times (IELT) before and during the desensitization program.

RESULTS

POIS was confirmed in both subjects, PE was confirmed in one male, and skin-prick tests with autologous semen in both subjects were positive. During the program, gradual reduction of complaints resulted in 60% and 90% amelioration of POIS complaints at 31 and 15 months, respectively, which coincided in one male with a delay of the IELT from 20 seconds at baseline to 10 minutes after 3 years of treatment. The cause of this association with IELT is unknown and remains to be elucidated.

CONCLUSIONS

Two males with POIS were successfully treated by hyposensitization with autologous semen, which supports an immunogenic/allergic etiology and underscores the clinical implication for immunological sexual medicine.

Postorgasmic Illness Syndrome (POIS) in 45 Dutch caucasian males: clinical characteristics and evidence for an immunogenic pathogenesis (Part 1)

INTRODUCTION

Postorgasmic illness syndrome (POIS) is a combination of local allergic symptoms and transient flu-like illness. In this study, the investigators propose five preliminary criteria to establish the diagnosis.

AIM

To describe the clinical details in 45 males being suspected of having POIS and to test an immunogenic hypothesis as the underlying mechanism of their presentations.

METHODS

Forty-five males were studied according to standardized protocol, including neuropsychiatric and medical sexological evaluations; their complaints were categorized using their own words, and their self-perceived intravaginal ejaculation latency time (IELT). Skin-prick testing with autologous diluted semen in 33 men were also performed.

MAIN OUTCOME MEASURES

Clinical features of POIS including self-perceived IELTs and the results of skin-prick testing with autologous diluted seminal fluid.

RESULTS

Of the 45 included men, 33 subjects consented with skin-prick testing. Of them, 29 (88%) men had a positive skin-prick test with their own (autologous) semen, and four had a negative test. In 87% of men, POIS symptoms started within 30 minutes after ejaculation. Complaints of POIS were categorized in seven clusters of symptoms, e.g., general, flu-like, head, eyes, nose, throat, and muscles. Local allergic reactions of eyes and nose were reported in 44% and 33% of subjects, a flu-like syndrome in 78% of subjects, exhaustion and concentration difficulties in 80% and 87% of subjects. Of all subjects, 58% had an atopic constitution. Lifelong premature ejaculation, defined as self-perceived IELT < 1 minute, was reported in 25 (56%) of subjects.

CONCLUSIONS

The combination of allergic and systemic flu-like reactions post-ejaculation together with a positive skin-prick test in the majority of males underscores the hypothesis of an "immunogenic" etiology of POIS, e.g., that POIS is caused by Type-1 and Type-IV allergy to the males' own semen, as soon it is triggered by ejaculation.