Tunical Outer Layer Plays an Essential Role in Penile Veno-occlusive Mechanism Evidenced from Electrocautery Effects to the Corpora Cavernosa in Defrosted Human Cadavers

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.

Comparing the effects of current circumcision techniques on dorsal root ganglia: an experimental study

Background

Circumcision is a surgical removal process of the preputium. Surgical excision and electric current cause neurodegeneration in the excised tissue-related neural network. This study investigates if circumcision and current surgical methods would cause histopathological changes in the penile tissue innervating pudendal nerve dorsal root ganglia.

Results

Vascular congestion occluded the microvessels, and degenerative changes were detected in postexcised penile tissue. Neuronal angulation, cytoplasmic condensation, nuclear shrinkage, and condensed nuclei were observed in the pudendal nerve ganglia. Moreover, the degenerated neuron (DN) densities of the pudendal nerve ganglia were 5 ± 2, 98 ± 22, 1093 ± 185, 236 ± 43 and 151 ± 19 in the control, the surgical circumcision, the monopolar cautery, the bipolar cautery and the thermocautery groups, respectively.

Conclusions

Although only the pudendal nerve endings are affected secondary to prepusium excision another pudendal axons can be damaged during bleeding control with cautery, the destruction of the neuron that sends this axon initiates a general inflammation in that ganglion. As a result, there may be a somatosensitive innervation defect in extrapenile tissues innervated by this ganglion. High-voltage electric devices should not be used unless obligatory.

3D reconstruction and histopathological analyses on murine corporal body

PURPOSE

Erectile dysfunction (ED) is one of the increasing diseases with aging society. The basis of ED derived from local penile abnormality is poorly understood because of the complex three-dimensional (3D) distribution of sinusoids in corpus cavernosum (CC). Understanding the 3D histological structure of penis is thus necessary. Analyses on the status of regulatory signals for such abnormality are also performed.

METHODS

To analyze the 3D structure of sinusoid, 3D reconstruction from serial sections of murine CC were performed. Histological analyses between young (2 months old) and aged (14 months old) CC were performed. As for chondrogenic signaling status of aged CC, SOX9 and RBPJK staining was examined.

RESULTS

Sinusoids prominently developed in the outer regions of CC adjacent to tunica albuginea. Aged CC samples contained ectopic chondrocytes in such regions. Associating with the appearance of chondrocytes, the expression of SOX9, chondrogenic regulator, was upregulated. The expression of RBPJK, one of the Notch signal regulators, was downregulated in the aged CC.

CONCLUSIONS

Prominent sinusoids distribute in the outer region of CC which may possess important roles for erection. A possibility of ectopic chondrogenesis induced by alteration of SOX9/Notch signaling with aging is indicated.

Dynamic erectile responses of a novel penile organ model utilizing TPEM†

Male penis is required to become erect during copulation. In the upper (dorsal) part of penis, the erectile tissue termed corpus cavernosum (CC) plays fundamental roles for erection by regulating the inner blood flow. When blood flows into the CC, the microvascular complex termed sinusoidal space is reported to expand during erection. A novel in vitro explant system to analyze the dynamic erectile responses during contraction/relaxation is established. The current data show regulatory contraction/relaxation processes induced by phenylephrine (PE) and nitric oxide (NO) donor mimicking dynamic erectile responses by in vitro CC explants. Two-photon excitation microscopy (TPEM) observation shows the synchronous movement of sinusoidal space and the entire CC. By taking advantages of the CC explant system, tadalafil (Cialis) was shown to increase sinusoidal relaxation. Histopathological changes have been generally reported associating with erection in several pathological conditions. Various stressed statuses have been suggested to occur in the erectile responses by previous studies. The current CC explant model enables to analyze such conditions through directly manipulating CC in the repeated contraction/relaxation processes. Expression of oxidative stress marker and contraction-related genes, Hypoxia-inducible factor 1-alpha (Hif1a), glutathione peroxidase 1 (Gpx1), Ras homolog family member A (RhoA), and Rho-associated protein kinase (Rock), was significantly increased in such repeated contraction/relaxation. Altogether, it is suggested that the system is valuable for analyzing structural changes and physiological responses to several regulators in the field of penile medicine.

Penile curvature after Peyronie's disease surgery: What are the risk factors?

Surgery is the golden standard for the treatment of patients with Peyronie's disease in chronic phase (12-18 months). Learning risk factors for post-surgical curvature (>20°) would aid both surgeon and patient in their decision-making process. The aim of this study was to investigate the risk factors for residual/recurrent curvatures. The clinical data of the patients, who underwent reconstructive surgery for PD between 1997 and 2016, were retrospectively reviewed. Follow-ups were performed via physical examination, surveys and phone calls. For shortening surgery (Nesbit/plication), initial bi-planar curvature was proved to be a predictor of post-operative curvature (p = .05). Lateral and ventral curvatures were associated with higher recurrence rates in patients who underwent grafting surgery (p = .01). In terms of baseline comorbidities, only diabetes mellitus had an association with curvature nonrecurrence for both shortening and lengthening surgeries (p < .05). Grafting surgery may be suggested to patients who had bi-planar curvatures instead of Nesbit surgery. Nesbit plication surgery may be preferred for patients with lateral and ventral curvatures instead of grafting surgery. Higher cavernosal blood pressures and more nocturnal erections of nondiabetic young patients might impede plication sutures and grafts and therefore increase penile curvature recurrence.

Potential Therapeutic Role of Dietary Supplementation with Spirulina platensis on the Erectile Function of Obese Rats Fed a Hypercaloric Diet

Spirulina platensis, an important source of bioactive compounds, is a multicellular, filamentous cyanobacterium rich in high-quality proteins, vitamins, minerals, and antioxidants. Due to its nutrient composition, the alga is considered a complete food and is recognized for its anti-inflammatory, antioxidant, antiobesity, and reproprotective effects. All of which are important for prevention and treatment of organic and metabolic disorders such as obesity and erectile dysfunction. The aim of this study was to investigate the modulatory role of Spirulina platensis food supplementation and the mechanisms of action involved in reversing the damage caused by a hypercaloric diet on the erectile function of rats. The animals were divided into a standard diet group (SD, n = 5); a hypercaloric diet group (HCD, n = 5); a hypercaloric diet group supplemented with S. platensis at doses of 25 (HCD+SP25, n = 5), 50 (HCD+SP50, n = 5), and 100 mg/kg (HCD+SP100, n = 5); and a hypercaloric diet group subsequently fed a standard diet (HCD+SD, n = 5). In the rats fed a hypercaloric diet, dietary supplementation with S. platensis effectively increased the number of erections while decreasing latency to initiate penile erection. Additionally, S. platensis increases NO bioavailability, reduces inflammation by reducing the release of contractile prostanoids, enhances the relaxation effect promoted by acetylcholine (ACh), restores contractile reactivity damage and cavernous relaxation, reduces reactive oxygen species (ROS), and increases cavernous total antioxidant capacity (TAC). Food supplementation with S. platensis thus restores erectile function in obese rats, reduces production of contractile prostanoids, reduces oxidative stress, and increases NO bioavailability. Food supplementation with S. platensis thus emerges as a promising new therapeutic alternative for the treatment of erectile dysfunction as induced by obesity.

Vacuum therapy prevents corporeal veno-occlusive dysfunction and penile shrinkage in a cavernosal nerve injured rat model

Erectile dysfunction and penile shrinkage are the common complications after radical prostatectomy. Penile rehabilitation is widely applied after the surgery. Vacuum therapy is one of the three penile rehabilitation methods used in the clinical setting, but its mechanism is not well known. This study was designed to investigate whether vacuum erectile device (VED) can prevent corporeal veno-occlusive dysfunction and penile shrinkage in the bilateral cavernous nerve crush (BCNC) rat model. Adult male Sprague-Dawley rats were randomly assigned into three groups: sham group, BCNC group, and BCNC + VED group. After 4 weeks, penile length and intracavernosal pressure (ICP) were measured, and then the middle part of the penis was harvested after dynamic infusion cavernosometry to complete the following items: smooth muscle/collagen ratios and collagen I/III ratios; ultramicrostructure of the tunica albuginea, endothelial cell, and smooth muscle cell; and the expression of calponin-1 and osteopontin. The penile shortening, peak ICP and ICP drop rate after alprostadil injection were significantly improved with vacuum therapy after 4-week treatment. Compared with BCNC group, VED significantly increased smooth muscle/collagen ratios, decreased collagen I/III ratios, and preserved the ultramicrostructure of the tunica albuginea, endothelial cell, and smooth muscle cell. The data also showed that animals exposed to VED could partially reverse the expression of calponin-1 and osteopontin induced by BCNC. In conclusion, vacuum therapy is effective to prevent penile shrinkage and veno-occlusive dysfunction in penile rehabilitation, which may be associated with well-preserved structure and function of the tunica albuginea, endothelial cell, and smooth muscle cell.

Development of a novel topical formulation of glyceryl trinitrate for the treatment of erectile dysfunction

Erectile dysfunction (ED), defined as the inability to initiate or maintain an erection sufficient for satisfactory sexual intercourse, is common, particularly in men aged ≥50 years. Existing treatments have significant limitations, and there remains a need for a fast-acting (to facilitate spontaneity during intercourse) and well tolerated local therapy. Topical glyceryl trinitrate (GTN) may meet this need because GTN undergoes rapid metabolism in penile smooth muscle and endothelial cells to produce nitric oxide, which plays a key role in the development of erection. This paper describes the rationale for the development of MED2005, a topical GTN formulation using DermaSys® technology, which is undergoing clinical trials for the treatment of ED. Pharmacokinetic studies have shown that MED2005 provides rapid delivery of GTN following application to the glans penis, and a Phase 2(a) trial in men with ED showed that MED2005 produced significant improvements in erectile function, compared with placebo. MED2005 was well tolerated in this trial, with only 21 cases of headache in 1003 intercourse attempts. It is anticipated that MED2005 will provide an effective therapy for ED, with a fast onset of action, good local tolerability, and fewer contraindications than phosphodiesterase 5 inhibitors, the current cornerstone of ED therapy.

Surgical niche for the treatment of erectile dysfunction

Penile erection implicates arterial inflow, sinusoidal relaxation and corporoveno-occlusive function. By far the most widely recognized vascular etiologies responsible for organic erectile dysfunction can be divided into arterial insufficiency, corporoveno-occlusive dysfunction or mixed type, with corporoveno-occlusive dysfunction representing the most common finding. In arteriogenic erectile dysfunction, corpora cavernosa show lower oxygen tension, leading to a diminished volume of cavernosal smooth muscle and consequential corporoveno-occlusive dysfunction. Current studies support the contention that corporoveno-occlusive dysfunction is an effect rather than the cause of erectile dysfunction. Surgical interventions have consisted primarily of penile revascularization surgery for arterial insufficiency and penile venous surgery for corporoveno-occlusive dysfunction, whatever the mechanism. However, the surgical effectiveness remained debatable and unproven, mostly owing to the lack of consistent hemodynamic assessment, standardized select patient and validated outcome measures, as well as various surgical procedures. Penile vascular surgery has been disclaimed to be the treatment of choice based on the currently available guidelines. However, reports on penile revascularization surgery support its utility in treating arterial insufficiency in otherwise healthy patients aged <55 years with erectile dysfunction of late attributable to arterial occlusive disease. Furthermore, it is noteworthy that penile venous surgery might be beneficial for selected patients with corporoveno-occlusive dysfunction, especially with a better understanding of the innovated venous anatomy of the penis. Penile vascular surgery might remain a viable alternative for the treatment of erectile dysfunction, and could have found its niche in the possibility of obtaining spontaneous, unaided and natural erection.