Anatomy of the mouse penis and internal prepuce

Advances in the study of the correlation between balanoposthitis and skin microecology

Balanoposthitis is a common heterogeneous skin condition involving the glans penis and prepuce, and is seen from infancy to old age. Its predisposing factors are intertrigo, lengthy foreskin, localized irritation, and mucosal injury. The itching and skin inflammation at the glans penis seriously affects the quality of life of patients. As a result of advances in high-throughput sequencing technology, the prepuce microbial colonization patterns and glans penis are now known better. Previous studies have shown that an imbalance of flora can cause balanoposthitis. This article summarizes the progress of research on balanoposthitis and skin microecology, and provides a direction for the subsequent exploration of immunological mechanisms in balanoposthitis.

Developmental and functional roles of androgen and interactive signals for external genitalia and erectile tissues

Background

Recent progress in molecular and signal analyses revealed essential functions of cellular signals including androgen and related growth factors such as Wnt regulators for external genitalia (ExG) development and its pathogenesis. Accumulated data showed their fundamental functions also for erectile tissue (corporal body) development and its abnormalities. The current review focuses on such signals from developmental and functional viewpoints.

Methods

Experimental strategies including histological and molecular signal analyses with conditional mutant mice for androgen and Wnt signals have been extensively utilized.

Main findings

Essential roles of androgen for the development of male-type ExG and urethral formation are shown. Wnt signals are associated with androgen for male-type ExG organogenesis. Androgen plays essential roles in the development of erectile tissue, the corporal body and it also regulates the duration time of erection. Wnt and other signals are essential for the regulation of mesenchymal cells of erectile tissue as shown by its conditional mutant mouse analyses. Stress signals, continuous erection, and the potential of lymphatic characteristics of the erectile vessels with sinusoids are also shown.

Conclusion

Reiterated involvement of androgen, Wnt, and other regulatory factors is stated for the development and pathogenesis of ExG and erectile tissues.

Androgenic induction of penile features in postnatal female mouse external genitalia from birth to adulthood: Is the female sexual phenotype ever irreversibly determined?

Female mice were treated for 35 days from birth to 60 days postnatal (P0, [birth], P5, P10, P20 and adult [∼P60]) with dihydrotestosterone (DHT). Such treatment elicited profound masculinization the female external genitalia and development of penile features (penile spines, male urogenital mating protuberance (MUMP) cartilage, corpus cavernosum glandis, corporal body, MUMP-corpora cavernosa, a large preputial space, internal preputial space, os penis). Time course studies demonstrated that DHT elicited canalization of the U-shaped clitoral lamina to create a U-shaped preputial space, preputial lining epithelium and penile epithelium adorned with spines. The effect of DHT was likely due to signaling through androgen receptors normally present postnatally in the clitoral lamina and associated mesenchyme. This study highlights a remarkable male/female difference in specification and determination of urogenital organ identity. Urogenital organ identity in male mice is irreversibly specified and determined prenatally (prostate, penis, and seminal vesicle), whereas many aspects of the female urogenital organogenesis are not irreversibly determined at birth and in the case of external genitalia are not irreversibly determined even into adulthood, the exception being positioning of the female urethra, which is determined prenatally.

Emerging structural and pathological analyses on the erectile organ, corpus cavernous containing sinusoids

Background

The corpus cavernosum (CC) containing sinusoids plays fundamental roles for erection. Analysis of pathological changes in the erectile system is studied by recent experimental systems. Various in vitro models utilizing genital mesenchymal-derived cells and explant culture systems are summarized.

Methods

3D reconstruction of section images of murine CC was created. Ectopic chondrogenesis in aged mouse CC was shown by a gene expression study revealing the prominent expression of Sox9. Various experimental strategies utilizing mesenchyme-derived primary cells and tissue explants are introduced.

Main Findings

Possible roles of Sox9 in chondrogenesis and its regulation by several signals are suggested. The unique character of genital mesenchyme is shown by various analyses of external genitalia (ExG) derived cells and explant cultures. Such strategies are also applied to the analysis of erectile contraction/relaxation responses to many signals and aging process.

Conclusion

Erectile dysfunction (ED) is one of the essential topics for the modern aged society. More comprehensive studies are necessary to reveal the nature of the erectile system by combining multiple cell culture strategies.

Extracellular vesicles from human urine-derived stem cells merged in hyaluronic acid ameliorate erectile dysfunction in type 2 diabetic rats by glans administration

BACKGROUND

The high prevalence of erectile dysfunction (ED) in patients with type 2 diabetes mellitus (DM2) is a challenging clinical problem. Researches on extracellular vesicles from urine-derived stem cells (USC-EVs) have shown that they have significant therapeutic effects in a variety of diseases by injection including ED. Hyaluronic acid (HA) is especially useful for delivering bioactive molecules. This study investigated the effects and related mechanisms of local administration of human USC-EVs combined with HA (USC-EVs-HA) on a rat model of DM2ED.

METHODS

UCSs were extracted from human urine samples and identified for preparation of the corresponding USC-EVs. The effects of high glucose and USC-EVs on human umbilical vein endothelial cells (HUVECs) were assessed in vitro using a CCK-8 assay to determine cell proliferation and pick the most appropriate concentration for subsequent experiments. Scratch and tube formation assays were performed to assess the function of HUVECs. Quantitative real-time polymerase chain reaction (PCR) was used to detect the expression of genes such as B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (BAX), and superoxide dismutase-2 (SOD2). HA, USC-EVs, and USC-EVs-HA were prepared at concentrations and then administered topically to DM2ED rats multiple times. Intracavernous pressure and mean arterial pressure were measured to assess erectile function in rats. Masson, Tunel, Immunohistochemistry, and Western blot analysis were performed to assess the fibrosis and endothelial function in corpus cavernosum, respectively.

RESULTS

Compared with the control group, the proliferation, migration ability, and tube-forming ability of HUVECs decreased in high glucose environment, while USC-EVs could optimize the function of HUVECs, reverse the expression of apoptotic genes, and enhance the antioxidant capacity. USC-EVs-HA showed improvement in ED compared to the HA and USC-EVs groups, and the 10-dose group was better than the 5-dose group. Histologically, the USC-EVs-HA group significantly improved apoptosis, angiogenesis, and smooth muscle regeneration in the corpus cavernosum compared to the HA group.

CONCLUSIONS

The topical application of USC-EVs-HA in the treatment of DM2ED rats has been proved effective. The potential mechanism might to promote the proliferation of endothelial cells and smooth muscle in the corpus cavernosum, which leads to the remodeling of erectile function. And multiple dosing at intervals may make the effect more pronounced.

Prostatic metaplasia of the vagina in transmasculine individuals

PURPOSE

To determine the prevalence of prostatic metaplasia in an expanded cohort of transmasculine individuals undergoing gender-affirming resection of vaginal tissue.

METHODS

Institutional Review Board approval was obtained. Clinical records were reviewed for all transmasculine individuals undergoing vaginal tissue resection at our institution between January 2018 and July 2021. Corresponding pathology specimens were examined grossly and microscopically, including immunohistochemical stains for NKX3.1, prostate-specific antigen (PSA), and androgen receptor (AR). Vaginal specimens from three patients without androgen supplementation were used as controls.

RESULTS

Twenty-one patients met inclusion criteria. The median age at surgery was 26.4 years (range 20.6-34.5 years). All patients had been assigned female gender at birth and lacked endocrine or genetic abnormalities. All were on testosterone therapy; median duration of therapy at surgery was 4.4 years (range 1.4-12.1 years). In the transmasculine group, no gross lesions were identified. Microscopically, all specimens demonstrated patchy intraepithelial glandular proliferation along the basement membrane and/or nodular proliferation of prostate-type tissue within the subepithelial stroma. On immunohistochemical staining, performed for a subset of cases, the glandular proliferation was positive for NKX3.1 (16/16 cases; 100%), PSA (12/14 cases; 85.7%), and AR (8/8 cases; 100%). Controls showed no evidence of prostatic metaplasia.

CONCLUSION

One hundred percent of vaginal specimens obtained from transmasculine individuals on testosterone therapy (21/21 cases) demonstrated prostatic metaplasia. Further investigation is warranted to characterize the natural history and clinical significance of these changes. Patients seeking hormone therapy and/or gender-affirming surgery should be counseled on the findings and their yet-undetermined significance.

Cornification and classical versus nonclassical androgen receptor signaling in mouse penile/preputial development

Mouse penile development is androgen-dependent. During development of male and female external genitalia, an internal ectodermal epithelial structure forms called the preputial lamina. At puberty the male preputial lamina canalizes to create the preputial space, effectively splitting into two layers: (a) the epithelial lining of the prepuce and (b) the surface epithelium of the penis. The female preputial lamina does not canalize, and instead remodels into the inverted U-shaped clitoral lamina of the adult female mouse. Androgen-dependent penile development was studied in transgenic mice with pathway-selective AR mutant transgenes through which AR signaling was activated either via the classical (AR-C) or the nonclassical pathway (AR-NC). Penile development and canalization of the preputial lamina was observed in AR-C and wild-type male mice naturally having both AR-C and AR-NC pathways. Conversely, clitoral development occurred in AR null (lacking both AR-C and AR-NC pathways) and AR-NC mice. The process of canalization of the preputial lamina seen in wild-type, AR-C and AR-C/AR-NC male mice involved cornification of the preputial lamina which involved up-regulation of keratin 10 and loricrin. Such up-regulation of these epidermal proteins was absent in the developing and adult clitoral lamina seen in wild-type female mice and AR-NC and AR null male (XY) mice. Thus, signaling through AR-C is sufficient to initiate and promote penile development and canalization of the preputial lamina, a process involving epithelial cornification.