An animal model of Peyronie's-like condition associated with an increase of transforming growth factor beta mRNA and protein expression

Injectable agents for the induction of Peyronie's disease in model rats: a comparative study

Peyronie's disease (PD) is a disorder characterized by fibrous plaque formation in the penile tissue that leads to curvature and complications in advanced stages. In this study, we aimed to compare four injectable induction agents for the establishment of a robust rat model of PD: transforming growth factor-β1 (TGF-β1), fibrin, sodium tetradecyl sulfate (STS) combined with TGF-β1, and polidocanol (POL) combined with TGF-β1. The results showed that injection of TGF-β1 or fibrin into the tunica albuginea induced pathological endpoints without causing penile curvature. The STS + TGF-β1 combination resulted in both histological and morphological alterations, but with a high incidence of localized necrosis that led to animal death. The POL + TGF-β1 combination produced pathological changes and curvature comparable to STS + TGF-β1 and led to fewer complications. In conclusion, fibrin, STS + TGF-β1, and POL + TGF-β1 all induced PD with a certain degree of penile curvature and histological fibrosis in rats. The POL + TGF-β1 combination offered comparatively greater safety and clinical relevance and may have the greatest potential for PD research using model rats.

Characterization of a novel rabbit model of Peyronie's disease

Peyronie's disease (PD) is a debilitating pathology which is associated with penile curvature and erectile dysfunction due to the formation of fibrotic plaques in the penile tunica albuginea. In the present study, we developed a novel rabbit model of PD via subtunical injection of recombinant transforming growth factor (TGF)-β1 protein and characterized erectile function and histopathological endpoints following plaque formation. Ten adult male, New Zealand white rabbits were randomized into 3 experimental groups including nonsurgical controls (NSC, N = 3) and those receiving subtunical injections of vehicle (N = 3) or TGF-β1 protein (0.5 µg/50 µl; N = 4). Following 1 month post-op, focal fibrous plaques composed of disorganized collagen type I and III bundles as well as fragmented elastin fibers at TGF-β1 injection sites were observed in contrast to control groups. Cavernosometric and cavernosographic evaluations revealed no significant differences in maximum intracorporal pressures or substantial curvature during papaverine-induced erection in either the vehicle or TGF-β1 cohorts. Immunohistochemical and histomorphometric analyses demonstrated significant increases in elastase 2B expression in TGF-β1-induced plaques as well as significant declines in matrix metalloproteinase (MMP)-2 and -9 expression relative to control levels. Our results demonstrate that PD-like fibrotic plaques can be created in the rabbit penile tunica albuginea following TGF-β1 injection.

Medical Treatment for Peyronie's Disease: Systematic Review and Network Bayesian Meta-Analysis

PURPOSE

To investigate the efficacy of medical treatment options for Peyronie's disease (PD) including oral drugs, intralesional treatment and mechanical treatment compared with placebo treatment using network meta-analysis (NMA).

MATERIALS AND METHODS

We searched the randomized controlled trials (RCTs) of PD in PubMed, Cochrane library, and EMBASE up to October 2022. RCTs included medical treatment options: oral drugs, intralesional treatment and mechanical treatment. Studies reporting at least one of the outcome measures of interest including curvature degree, plaque size, and structured questionnaires (International Index of Erectile Function, IIEF) were included.

RESULTS

Finally, 24 studies including 1,643 participants met our selection criteria for NMA. There was no statistically significant treatment compared to placebo of the curvature degree, plaque size, IIEF in Bayesian analysis. The SUCRA values of ranking probabilities for each treatment performance, which indicated that hyperthermia device ranked first in NMA. However, in frequentist analysis, 7 of mono treatments (coenzyme Q10 [CoQ10] 300 mg, hyperthermia device, interferon alpha 2b, pentoxifylline 400 mg, propionyl-L-carnitine 1 g, penile traction therapy [PTT], vitamin E 300 mg) and 2 of combination treatments ("PTT-extracorporeal shockwave treatment", "vitamin E 300 mg-propionyl-L-carnitine 1 g") were statistically significant for improvement of curvature degree, and 9 of mono treatments (CoQ10 300 mg, hyaluronic acid 16 mg, hyperthermia device, interferon alpha 2b, pentoxifylline 400 mg, propionyl-L-carnitine 1 g, verapamil 10 mg, vitamin E 300 mg, vitamin E 400 U) and 3 of combination treatments ("interferon alpha 2b-vitamin E 400 U", "verapamil 10 mg-antioxidants", "vitamin E 300 mg-propionyl-L-carnitine 1 g") were statistically significant in the improvement of plaque size.

CONCLUSIONS

At present, there is no clinical treatment alternatives that have been demonstrated to be effective compared to placebo. Nonetheless, as the frequentist approach has shown that a number of agents are efficacious, further research is expected to develop more effective treatment options.

European Society of Sexual Medicine consensus statement on the use of animal models for studying Peyronie's disease

Introduction

Animal models are frequently used for translational research in Peyronie's disease (PD). However, due to lack of availability of guidelines, there is some heterogeneity in study design, data reporting, and outcome measures.

Aim

This European Society for Sexual Medicine consensus statement aims to provide guidance in utilization of animal models in PD research in a standardized and uniform fashion.

Methods

PubMed was searched for studies using animal models for PD. The following search terms were used: ("Peyronie's disease" OR "penile fibrosis" OR "penile curvature" OR "induration penis plastica" OR "erectile dysfunction") AND ("rodent" OR "mouse" OR "mice" OR "rat" OR "rabbit").

Outcomes

This European Society for Sexual Medicine statement describes best practice guidelines for utilization of animals in PD research: power calculation, details of available models, surgical procedures, and measurement techniques, while highlighting possible pitfalls and translational limitations of the models.

Results

In total, 2490 studies were retrieved and 2446 articles were excluded. A total of 44 studies were included, of which 40 studies used rats, 1 study used both rats and mice, 1 study used a genetic mouse model, and 2 studies used rabbits. A significant number of the studies (70.5%) used transforming growth factor β 1 for induction of fibrosis. Oxford 2011 Levels of Evidence criteria could not be applied due to the nature of the studies.

Conclusion

Despite certain limitations of PD animal models presented, we aimed to provide guidance for their appropriate use in translational research, with the purpose of improving study quality and reproducibility as well as facilitating interpretation of reported results and conclusions.

Research progress of functional motifs based on growth factors in cartilage tissue engineering: A review

Osteoarthritis is a chronic degenerative joint disease that exerts significant impacts on personal life quality, and cartilage tissue engineering is a practical treatment in clinical. Various growth factors are involved in cartilage regeneration and play important roles therein, which is the focus of current cartilage repair strategy. To compensate for the purification difficulty, high cost, poor metabolic stability, and circulating dilution of natural growth factors, the concept of functional motifs (also known as mimetic peptides) from original growth factor was introduced in recent studies. Here, we reviewed the selection mechanisms, biological functions, carrier scaffolds, and modification methods of growth factor-related functional motifs, and evaluated the repair performance in cartilage tissue engineering. Finally, the prospects of functional motifs in researches and clinical application were discussed.

The Immunological Microenvironment and the Emerging Role of Stem Cells Therapy in Peyronie's Disease: A Systematic Narrative Review

Current literature has indicated that Peyronie's disease (PD) could be initiated by microtrauma and the subsequent inflammation episodes that follow. PD could be sorted into acute or chronic status, and it can differ when selecting the clinical therapeutics. PD would cause pain and penile deformity to diseased men and impair their erectile function. Occasionally, surgical revision of the penis might be needed to correct the penile curvature. We find that there are limited effective options of intra-lesion injections for the PD plaques. By searching the databases and screening the literature with the PRISMA 2020 guideline, we observed that several preclinical studies that applied stem cell therapy in treating PD were fruitful in the acute phase. Although in the chronic phase of PD, erectile parameters were not significantly improved, and therefore, future studies might be better elevated in certain aspects, such as the sites selected for harvesting stem cells or changing the centrifugation forces. In this review, we concluded the contemporary understanding of inflammatory microenvironments in PD, the stem cell therapy in PD, and our perspectives on future studies. We concluded that there may be great potential in stem cell therapy for treating both acute and chronic phases PD.

Articular cartilage reconstruction with TGF-β1-simulating self-assembling peptide hydrogel-based composite scaffold

Transforming growth factor-β (TGF-β) is an important inducing factor for the differentiation of mesenchymal stem cells and the secretion of collagen II, but the inaccessibility and instability limit its application in clinical practice. In this study, the TGF-β1-simulating peptide LIANAK (CM) was connected with the self-assembling peptide Ac-(RADA)₄-CONH₂ (RAD) to obtain the functionalized self-assembling peptide Ac-(RADA)₄-GG-LIANAK-CONH₂ (RAD-CM). The results indicated that the CM-functionalized RAD hydrogel contributed to the enhanced expressions of chondrogenic genes and extracellular matrix deposition. The self-assembling peptides were then combined with decellularized cartilage extracellular matrix (DCM) to construct a composite scaffold for articular cartilage repair. The CM-functionalized composite scaffold RAD/RAD-CM/DCM (R/C/D) exhibited good bioactivity and structural stability and exhibited satisfactory performance in promoting neocartilage restoration and the reconstruction of the osteochondral unit. This study provides a promising strategy for in situ cartilage regeneration via the stable presentation of TGF-β1-simulating peptide. STATEMENT OF SIGNIFICANCE: Deficiency of effective chondrogenic inducers (especially, the TGF-β family) significantly limits the self-regeneration of cartilage in osteochondral defect cases. Oligopeptide LIANAK, named CM, could simulate TGF-β1's bioactivity with particular structure, but traditional chemical crosslinking to polymer scaffolds resulted in risks of safety and complication, which is unfavorable for clinical applications. Here, self-assembling peptide RAD was used to load CM, to obtain a TGF-β1 mimetic peptide hydrogel. Depending on the homology (amino acids) of RAD and CM, the synthesis of the whole peptide only needs simply extended sequences of CM following that of RAD by automated solid-phase peptide synthesis. The modified peptide effectively demonstrated osteochondrogenic bioactivity, ensured the convenience, safety, and mass production, which displayed great potential in tissue engineering research and translational medicine.

RNA-sequencing profiling analysis of pericyte-derived extracellular vesicle-mimetic nanovesicles-regulated genes in primary cultured fibroblasts from normal and Peyronie's disease penile tunica albuginea

BACKGROUND

Peyronie's disease (PD) is a severe fibrotic disease of the tunica albuginea that causes penis curvature and leads to penile pain, deformity, and erectile dysfunction. The role of pericytes in the pathogenesis of fibrosis has recently been determined. Extracellular vesicle (EV)-mimetic nanovesicles (NVs) have attracted attention regarding intercellular communication between cells in the field of fibrosis. However, the global gene expression of pericyte-derived EV-mimetic NVs (PC-NVs) in regulating fibrosis remains unknown. Here, we used RNA-sequencing technology to investigate the potential target genes regulated by PC-NVs in primary fibroblasts derived from human PD plaque.

METHODS

Human primary fibroblasts derived from normal and PD patients was cultured and treated with cavernosum pericytes isolated extracellular vesicle (EV)-mimetic nanovesicles (NVs). A global gene expression RNA-sequencing assay was performed on normal fibroblasts, PD fibroblasts, and PD fibroblasts treated with PC-NVs. Reverse transcription polymerase chain reaction (RT-PCR) was used for sequencing data validation.

RESULTS

A total of 4135 genes showed significantly differential expression in the normal fibroblasts, PD fibroblasts, and PD fibroblasts treated with PC-NVs. However, only 91 contra-regulated genes were detected among the three libraries. Furthermore, 20 contra-regulated genes were selected and 11 showed consistent changes in the RNA-sequencing assay, which were validated by RT-PCR.

CONCLUSION

The gene expression profiling results suggested that these validated genes may be good targets for understanding potential mechanisms and conducting molecular studies into PD.

Clinical use of hyaluronic acid in andrology: A review

Background

Hyaluronic acid is a glycosaminoglycan widely used in the fields of orthopedics, ophthalmology, and aesthetic medicine due to its significant ability to reduce the synthesis of pro‐inflammatory proteins and its activity against oxidative stress, a feature of many degenerative illnesses.

Objectives

The objective of the present review is to provide a comprehensive narrative review of the most recent literature on the use of hyaluronic acid in andrology in order to facilitate the use of this therapeutic device in the common clinical practice of many physicians. Specific conditions covered in the review are Peyronie's disease, premature ejaculation, and penile enlargement.

Materials and methods

A broad and comprehensive literature search included Medline, EMBASE, and the Cochrane Libraries, with no time restriction up to December 2020 and restricted to English language publications. Unpublished studies were not included. The study was registered as “The role of hyaluronic acid in andrology: A systematic review and meta‐analysis” in PROSPERO with the ID CRD42021223416.

Discussion and conclusion

Hyaluronic acid is a valid choice for the treatment of Peyronie's disease in terms of the resolution of the acute phase of the disease and of contributing to stabilizing the disease as a bridge to potential surgery. Data, furthermore, suggest that hyaluronic acid is frequently associated with an overall clinical improvement, allowing the patient to resume normal sexual activity.

With regard to premature ejaculation, data suggests hyaluronic acid‐based treatments were effective in prolonging intra‐vaginal ejaculation time. Furthermore, hyaluronic acid was found to be safe and well‐tolerated, with main adverse events limited to local discomfort, ecchymosis, papule formation, and glans numbness, all of which were reported to resolve spontaneously.

Last, with regard to penile enlargement, the overall perception of experts is that hyaluronic acid may be an extremely well‐tolerated compound with potential for application in specific areas of male sexual health that are often neglected as compared to more common, and relatively simpler to treat, conditions.

Ectopic Germinal Centres with B and T Cells and Follicular Dendritic Cell Networks in Urethral Stricture Tissue: Possible Avenue for Immunological Treatments

BACKGROUND

The underlying cause of a urethral stricture can sometimes be obscure. It is possible that an injury to the urethra induces an immunological cascade that generates scar tissue and fibrosis, eventually resulting in a stricture. If such immunological reactions could be better elucidated, immunological therapies could possibly emerge.

OBJECTIVE

To evaluate if ectopic germinal centres exist in urethral stricture disease.

DESIGN SETTING AND PARTICIPANTS

Resected stricture specimens from 45 patients undergoing open bulbar urethroplasty with excision and anastomosis were assessed. Histopathological characteristics, such as fibrosis (grade I-III), inflammation, and sclerosis, were evaluated using immunostaining for CD3 (T cells), CD20 (B cells), and CD21 (follicular dendritic cells).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome measure was the presence or absence of a germinal centre. The secondary outcome was evaluation of any correlation between the degree of fibrosis and germinal centres. Fisher's exact test was used for univariate analysis.

RESULTS AND LIMITATIONS

In six patients, ectopic germinal centres were found. In ten patients, there was no inflammation at all. There was no correlation found between the degree of fibrosis and the abundance of immunohistochemically detected immune cells.

CONCLUSIONS

Ectopic germinal centres, with B and T cells as well as follicular dendritic cell networks, do exist in urethral stricture disease. This finding may open up for novel research avenues on the possibility of adopting immunological treatments for urethral stricture disease.

PATIENT SUMMARY

In patients with a narrowing of the urethra due to any kind of trauma, we looked for the presence of centres of immunological reaction in urethral tissue. We identified these immunological centres (also called germinal centres) in some patients. This intriguing finding suggests that immunological treatments may have potential for men with scar tissue in a narrowed urethra.

Is Peyronie's an IgG4-related disease?

OBJECTIVE

We believe that IgG4 may have a role in the pathogenesis of Peyronie's disease (PD), and this role could be particularly beneficial for developing new strategies; therefore, we aimed to investigate the role of IgG4 in PD.

METHODS

This study included 3 groups with a total of 139 subjects: (I) PD group (n=61), (II) control group (n=48), and (III) benign prostatic hyperplasia (BPH) group (n=30). IgG4 measurement was performed using the enzyme-linked immunosorbent assay. Plaque size, penile curvature, and the presence of concomitant impotence were evaluated in the PD group. Impotence was assessed based on the International Index of Erectile Function (IIEF).

RESULTS

A significant difference was observed between the PD and control groups and between the PD and BPH groups with regard to IgG4 levels, while no significant difference was found between the BPH and control groups (p=0.0001, p=0.002, and p=0.07, respectively). The IgG4 levels were significantly higher in the PD than in the other groups. The cutoff value determined between the groups was 87.5, 82, and 31.5, respectively. Mean plaque size was 2.0±1.01 cm, and a significant relationship was found between plaque size and IgG4 concentration (p=0.02). Mean penile curvature was 35.6±25.1°, and a significant relationship was found between penile curvature of >60° and IgG4 concentration (p=0.001). Mean IIEF score was 19 (range, 7-25). Moreover, no significant relationship was found between erectile dysfunction and IgG4 concentration. Penile pain was present in 24 (39.3%) patients with PD.

CONCLUSION

The IgG4 levels were significantly increased in patients with PD, which implies that IgG4 may have a role in the pathogenesis of PD. This finding could be particularly beneficial for developing new strategies. Future studies with larger patient series are needed to substantiate our findings.

Evolving therapies for Peyronie's disease: how can we work towards new drugs?

Peyronie's disease (PD) is an idiopathic chronic fibrotic disease that causes a penile curvature (PC), subsequent erectile dysfunction (ED) and impaired sexual intercourse in patients. As of yet, there are no reliable non-surgical treatment options available. Intralesional injection with collagenase Clostridum Histolyticum has been FDA approved since 2013, but post-approval studies have not been unanimously positive. Moreover, it renders a curvature improvement of only 30% on average, usually still requiring surgical intervention to remedy PC. Therefore, there is a need for drugs which could prevent surgery altogether. Development of new drugs can either be through a target-based or phenotypic assay-based approach. The current in vivo model for PD is dependent on treatment of primary PD-derived fibroblasts with transforming growth factor-β1. Moreover, despite the existence of a genetic in vivo PD model, it does not allow for drug screening or testing. While some advances have been made in the past few years, new in vivo and in vivo systems and well-designed studies are urgently needed for the non-surgical treatment of PD.

Laser Therapy for Peyronie's Disease: A Randomized Control Double-Blind Pilot Study

Introduction: The management of Peyronie's disease (PD) has remained a therapeutic dilemma for physicians and there is no gold standard treatment. In this paper, we decided to investigate the beneficial effect of the intralesional administration of verapamil compared with the intralesional administration of verapamil plus a low-intensity laser (LIL). Methods: Research was activated from May 2016 to May 2018 and a total of 38 men aged 18 years and older completed the investigation. The subjects were randomly divided into 2 groups. Group 1 was composed of 22 patients that were treated only by verapamil (5 mg) plus a sham laser weekly for 6 weeks, and group 2 consisted of 22 patients that received a laser, using the BTL-6000 HIGH-INTENSITY LASER 12 W machine and the same protocol of intralesional verapamil injection. The visual analogue scale (VAS) was used to evaluate pain during an erection, penile ultrasonography was used to measure plaque size, the penile curvature angle degree was measured using the photographs taken during an erection, and the International Index of Erectile Function questionnaire was used to assess erectile function. The follow-up treatment lasted for nine months, with visits performed in the 3rd and 9th months. Results: All study parameters decreased significantly after treatment in both arms, but the reduction in pain and penile curvature improvements in combination therapy revealed more significant changes in 3 months (p = .035, p=.032). Nevertheless, these improvements were not seen in the follow-up session after 9 months. Conclusion: A laser appears to be safe treatment modality in carefully-selected patients with PD. It has moderate efficacy in the short term.

Physicochemical and biochemical spatiotemporal maps of a mouse penis

Spatiotemporal mechanobiology resulting in penile pathologies continues to be investigated using small scale animals models such as mice. However, species-dependent functional biomechanics of a mouse penis, is not known. In this study, spatial mapping of a mechanosensitive transcription factor, scleraxis (Scx), at ages 4, 5, 6 weeks, and 1 year were generated to identify mechanoactive regions within penile tissues. Reconstructed volumes of baculum collected using micro X-ray computed tomography illustrated significantly increased baculum length with decreased porosity, and increased mineral density (p < 0.05) with age. The bony-baculum was held centrally in the Scx positive corpus cavernosum glandis (CCG), indicating mechanoactivity within the struts in a 6 week old mouse. The struts also were stained positive for fibrillar proteins including collagen and elastin, and globular proteins including protein gene product 9.5, and α-smooth muscle actin. The corpus cavernosum penis (CCP) contained significantly (p < 0.05) more collagen than CCG within the same penis, and both regions contained blood vessels with equivalent innervation at any given age. Comparison of volumes of flaccid and erect penile forms revealed functional characteristics of the CCP. Results of this study provided insights into biomechanical function of the CCG; in that, it is a high-pressure chamber that stiffens the penis and is similar to the human corpus cavernosum.

A review of inflammation and fibrosis: implications for the pathogenesis of Peyronie's disease

Peyronie's disease (PD) is a superficial fibrosing disorder that causes penile deformity and can interfere with sexual intercourse and reproduction, as well as diminish quality of life. While the exact mechanism of PD is still being investigated, there is likely a genetic component to the predisposition to penile plaque formation. Ultimately, however, perturbations in normal wound healing and aberrant deposition of extracellular matrix components lead to fibrotic tissue deposition. Fibrosis in PD is regulated by a complex pathway of inflammatory and fibrotic mediators. Currently there are no treatments for PD that address an underlying cause or disease progression. In this review, we provide an overview of the known inflammatory and fibrotic mediators of PD and explore the pathophysiology of other human superficial fibrosing disorders to develop further insights into PD.

Anti-fibrotic effect of mycophenolate mofetil on Peyronie's disease experimentally induced with TGF-β

The aim of the present study was to evaluate the histological, histochemical, and stereological changes caused by mycophenolate mofetil (MMF) on the tunica albuginea of rat penises submitted to an injection of transforming growth factor beta (TGF-β) for the induction of Peyronie's disease (PD). Twenty adult male Wistar rats were divided into four groups: Control group; TGF-β group (TGF-β injection); MMF-7d group (treated with MMF 7 days after induction with TGF-β); and MMF-30d group (treated with MMF 30 days after induction with TGF-β). The steorological evaluation included the relative volume of different types of connective fibres of the tunica albuginea. The histochemical analysis revealed the fragmentation and degradation of elastin in the tunica albuginea. This process was partially reversed in the MMF-7d group and a situation very close to normality was observed in the MMF-30d group. In the collagen III/collagen I ratio it was observed increase in this ratio in the TGF-β (59.4 ± 5.53) and MMF-7d (49 ± 18.2) groups and a decrease in the MMF-30d group (28.7 ± 4), approaching normality. The injection of TGF-β promoted fibrotic alterations in the penile tunica albuginea in Wistar rats corresponding to PD. In this model, MMF acts as a regenerating anti-fibrotic agent.

Simvastatin and the Rho-kinase inhibitor Y-27632 prevent myofibroblast transformation in Peyronie's disease-derived fibroblasts via inhibition of YAP/TAZ nuclear translocation

OBJECTIVES

To uncover the anti-myofibroblast (MFB) properties of Rho-kinase inhibitor (compound Y-27632) and simvastatin in an in vitro model of Peyronie's disease (PD), a sexually debilitating disease caused by an irreversible fibrotic plaque in the penile tunica albuginea (TA).

MATERIALS AND METHODS

Primary human fibroblasts (FBs) were isolated from surgically obtained TA tissue from patients with PD. To induce MFB status, cells were stimulated with 3 ng/mL transforming growth factor-β1 (TGF-β1). Increasing doses of Y-27632 and simvastatin were added. Real-time quantitative PCR was used to assess mRNA expression of α-smooth muscle actin (α-SMA), collagen III, elastin and connective tissue growth factor (CTGF) after 72 h. Western blot analysis was used to quantify α-SMA protein contents, and immunofluorescence (IF) was used to visualize MFB differentiation by staining for α-SMA after 72 h. A resazurin-based assay was used to assess cell viability to ensure the anti-MFB effect of the drugs. A mechanistic study was performed using IF staining for YAP/TAZ nuclear translocation.

RESULTS

After 72 h of stimulation with TGF-β1, a six- to 10-fold upregulation of α-SMA could be observed. When treated with Y-27632 or simvastatin, the α-SMA, collagen III, elastin and CTGF mRNA expression was impeded. Additionally, TGF-β1 stimulation showed a twofold increase in α-SMA protein expression, which was reversed to non-stimulated levels after treatment with Y-27632 and simvastatin. Using IF, stimulated cells were identified as MFB (α-SMA+, Vim+) as opposed to the non-stimulated, Y-27632- and simvastatin-treated cells (α-SMA-, Vim+). The resazurin-based assay confirmed that the cell viability was not compromised by the administered drugs. On stimulation with TGF-β1, nuclear translocation of YAP/TAZ could be observed, which was prevented by adding the aforementioned compounds.

CONCLUSION

Transformation of FBs into the contractile and extracellular matrix-producing MFBs occurs after TGF-β1 stimulation. In our experiments, Rho-kinase inhibition and simvastatin treatment were shown to prevent this in TGF-β1-stimulated cells on an RNA and protein level through the inhibition of YAP/TAZ nuclear translocation. Y-27632 and simvastatin could become a novel treatment option in the early treatment of PD.

Sclerosis as a predictive factor for failure after bulbar urethroplasty: a prospective single-centre study

OBJECTIVE

The aim of this study was to assess whether sclerosis in histology following bulbar urethroplasty is a predictive factor for failure of surgery.

MATERIALS AND METHODS

Resected stricture specimens from 45 patients undergoing open urethroplasty with excision and anastomosis were collected prospectively during 2011-2014. Histopathological characteristics, including fibrosis (grade I-III), inflammation and sclerosis, were evaluated using different routine staining. These specimens were compared to normal urethral resection specimens from patients undergoing sex-correction surgery. The uropathologist who conducted the analyses was blinded to the study design.

RESULTS

The outcomes of the histological classifications were as follows: 19 patients had grade I fibrosis, of whom three had failures; 13 patients had grade II fibrosis, without any failures; and the most severe fibrosis, grade III, including sclerosis, was found in 13 patients (11 with sclerosis), with failure in eight. Sclerosis was a significant risk factor for restricture when comparing patients with sclerosis and those without sclerosis, and likewise when adjusting for age, inflammation and stricture length.

CONCLUSION

Histological findings of sclerosis in the resected urethral stricture specimen indicate a significantly higher risk for restricture after urethroplasty surgery.

Stem cell therapy for the treatment of Peyronie's disease

INTRODUCTION

Like other fibrotic diseases, the cause of Peyronie's disease (PD) is still obscure. Since there is now increasing evidence for the role of Mesenchymal Stem Cells (MSCs) as potential treatment to fibrosis, it is crucial to determine their possible efficacy in the treatment of PD. Areas covered: In this review, the authors summarize the emerging data and published studies regarding the use of SCs for the treatment of PD. The authors provide particular focus on the three-first experimental studies for the use of SCs in rat models as well as the sole two studies undertaken in humans. Expert opinion: It seems evident in experimental settings that SCs in general (Adipose Derived SCs in particular) provide a feasible, safe and effective therapy for PD. The potential limits of the rat models used initially have been somewhat overcome with the inception of studies in men. However, further prospective studies are needed in humans to further elucidate the therapeutic potential of stem cell therapy in PD.

Understanding the cellular basis and pathophysiology of Peyronie's disease to optimize treatment for erectile dysfunction

Erectile dysfunction (ED) is a common condition that significantly impacts a man’s physical and psychological well-being. ED is often associated with Peyronie’s disease (PD), which is an abnormal curvature of the penis. Delayed treatment of or surgical invention for PD often results in ED and therefore unsatisfied patients. The pathophysiology of PD is incompletely understood, but has been studied extensively and based on our current understanding of PD physiology, many medical treatment options have been proposed. In this paper, we will review what is known about the pathophysiology of PD and the medical treatment options that have been trialed as a result. More investigations in regards to the basic science of PD need to be carried out in order to elucidate the exact mechanisms of the fibrosis, and propose new, more successful treatment options which should be implemented prior to the onset of ED.

Intralesional Injection of Hyaluronic Acid in Patients Affected With Peyronie's Disease: Preliminary Results From a Prospective, Multicenter, Pilot Study

Introduction

Hyaluronic acid has been shown to be efficacious in decreasing scar formation, inflammation, and oxidative stress.

Aim

To assess the efficacy of intralesional injection of hyaluronic acid in patients affected by Peyronie's disease.

Methods

In this prospective, single-arm, self-controlled, interventional, multicenter pilot study, 65 patients underwent a 10-week cycle of weekly intraplaque injections with hyaluronic acid (0.8% highly purified sodium salt hyaluronic acid 16 mg/2 mL; Sinovial, IBSA, Lodi, Italy). Patients were re-evaluated 2 months after the end of therapy.

Main Outcome Measures

Plaque size (millimeters), penile curvature (degrees), International Index of Erectile Function (IIEF-5) score, visual analog scale (VAS) score for sexual satisfaction, and Patient's Global Impressions of Improvement (PGI-I) score.

Results

Median age was 57 years (range = 23–70). At baseline, mean plaque size was 10 mm (range = 3–30 mm), mean penile curvature was 30° (range = 0°–50°), and mean IIEF-5 score was 20 (range = 0–25), with slight to moderate erectile dysfunction (IIEF score < 21) in 36 of 65 patients (55%). A median VAS score of 6 (range = 2–10) was found. Mean follow-up was 12 months (range = 6–24 months). Statistically significant post-treatment improvements were detected for plaque size (before treatment = 10 mm [3–30 mm], after treatment = 8 mm [1–30 mm], P < .0001), penile curvature (before treatment = 30° [0°–50°], after treatment = 20° [0°–40°], P < .0001), IIEF-5 score (before treatment = 20 [11–25], after treatment = 21 [15–25], P < .0001), and VAS score (before treatment = 6 [2–10], after treatment 8 [2–10], P < .0001). After treatment, the rate of patients with an IIEF score lower than 21 decreased from 55% (36 patients) to 40% (25 patients). Overall improvement on the PGI-I questionnaire was 69%.

Conclusion

Intralesional treatment with hyaluronic acid can improve plaque size, penile curvature, and overall sexual satisfaction and seems preferably indicated in the early (active) phase of the disease. Furthermore, it is easy to perform and well tolerated.

The Genetic Basis of Peyronie Disease: A Review

INTRODUCTION

Peyronie disease (PD) is a progressive fibrotic disorder of the penile tunica albuginea that results in fibrotic penile plaques and can lead to penile deformity. Characterized by aberrant fibrosis resulting in part from the persistence of myofibroblasts and altered gene expression, the molecular factors underpinning PD and other related fibrotic diatheses are just being elucidated. A genetic link to PD was first identified three decades ago using pedigree analyses. However, the specific genetic factors that predispose patients to aberrant fibrosis remain unknown, and the relations between these fibrotic conditions and other heritable diseases, including malignancy, are uncharacterized.

AIM

To review the current landscape linking molecular and genetic factors to aberrant fibrosis in PD and related fibrotic diatheses, including Dupuytren disease.

METHODS

Review and evaluation of the literature from 1970 to the present for genetic factors associated with PD were performed.

MAIN OUTCOME MEASURES

Data describing the genetic factors associated with PD were obtained.

RESULTS

We describe the known structural chromosomal abnormalities and single-nucleotide polymorphisms associated with fibrotic diatheses and discuss the spectrum of differential gene expression data comparing normal tissues with those derived from men with PD or Dupuytren disease. We discuss epigenetic mechanisms that might regulate gene expression and alter predisposition to fibrosis.

CONCLUSION

Although the current understanding of the genetic factors associated with PD is limited, significant advances have been made during the past three decades. Further research is necessary to provide a more comprehensive understanding of the landscape of genetic factors responsible for the development of PD.

Tunica albuginea allograft: a new model of LaPeyronie's disease with penile curvature and subtunical ossification

The pathophysiology of LaPeyronie's disease (PD) is considered to be multifactorial, involving genetic predisposition, trauma, inflammation and altered wound healing. However, these factors have not yet been validated using animal models. In this study, we have presented a new model obtained by tunica albuginea allograft. A total of 40, 16-week-old male rats were used. Of these, 8 rats served as controls and underwent a 10 × 2-mm-wide tunical excision with subsequent autografting, whereas the remaining 32 underwent the same excision with grafting of the defect with another rat's tunica. Morphological and functional testing was performed at 1, 3, 7 and 12 weeks after grafting. Intracavernous pressure, the degree of penile curvature and elastic fiber length were evaluated for comparison between the allograft and control groups. The tissues were obtained for histological examination. The penile curvature was significantly greater in the allografted rats as compared with the control rats. The erectile function was maintained in all rats, except in those assessed at 12 weeks. The elastin fiber length was decreased in the allografted tunica as compared to control. SMAD2 expression was detected in the inner part of the allograft, and both collagen-II- and osteocalcin-positive cells were also noted. Tunica albuginea (TA) allograft in rats is an excellent model of PD. The persistence of curvature beyond 12 weeks and the presence of ossification in the inner layer of the TA were similar to those observed in men with PD. Validation studies using this animal model would aid understanding of the PD pathophysiology for effective therapeutic interventions.

Estradiol attenuates the TGF-β1-induced conversion of primary TAFs into myofibroblasts and inhibits collagen production and myofibroblast contraction by modulating the Smad and Rho/ROCK signaling pathways

The transformation of tunica albuginea-derived fibroblasts (TAFs) into myofibroblasts plays an important role in the pathological progress of Peyronie's disease (PD). However, no treatment which addresses this transformation is currently available. Estrogen has been shown to inhibit the progression of fibrosis in a number of fibrotic diseases. The aim of this study was to determine whether estrogen [17β‑estradiol (E2)] suppresses the diffentiation of primary rat TAFs into myofibroblasts in vitro. TAFs obtained from male Sprague‑Dawley rats were stimulated with either transforming growth factor‑β1 (TGF‑β1) or E2. Western blot analysis and immunofluorescence staining were used to assess changes in the expression levels of α‑smooth muscle actin (αSMA). The expression levels of additional proteins (GAPDH, p‑Smad2, Smad2, Smad4, RhoA, Rac1, ROCK1 and ROCK2) were also measured by western blot analysis. We used collagen gel assays to assess cell contractility. Additionally, the concentration of hydroxyproline in the TAF cell culture medium was detected using commercially available kits. We found that E2 reduced αSMA expression which was induced by TGF‑β1. E2 also suppressed the TGF‑β1‑induced increase in the concentration of hydroxyproline (a marker of collagen) in addition to suppressing the contraction of TAFs. The key processes affected by TGF‑β1 treatment included the phosphorylation of Smad2, ras homolog gene family, member A (RhoA) and Rho‑associated, coiled-coil containing protein kinase 2 (ROCK2); this increase in phosphorylation was inhibited by treatment with E2. Collectively, these results demonstrate that by modulating the activation of the TGF‑β1‑Smad and RhoA‑ROCK2 signaling pathways, E2 inhibited the transformation of TAFs into myofibroblasts, decreased the expression of collagen and suppressed the contraction of myofibroblasts in response to TGF-β1 stimulation.

Intratunical Injection of Genetically Modified Adipose Tissue-Derived Stem Cells with Human Interferon α-2b for Treatment of Erectile Dysfunction in a Rat Model of Tunica Albugineal Fibrosis

INTRODUCTION

Peyronie's disease (PD) has frequently been associated with erectile dysfunction (ED) and may further compromise coitus.

AIM

To investigate the efficacy of intratunical injection of genetically modified rat adipose tissue-derived stem cells (ADSCs) expressing human interferon α-2b (ADSCs-IFN) in decreasing fibrosis and restoring erectile function in a rat model of tunica albugineal fibrosis (TAF).

METHODS

A total of 36 Sprague-Dawley rats (12 weeks old; 300-350 g) were randomly divided in six equal groups: (i) sham group (50 μL saline-injected into the tunica albuginea [TA]); (ii) TAF group (transforming growth factor [TGF]-β1 [0.5 μg/50 μL] injected into the TA); (iii) TGF-β1 plus 5 × 10(5) control ADSCs injected same day; (iv) TGF-β1 plus 5 × 10(5) ADSCs-IFN injected same day; (v) TGF-β1 plus 5 × 10(5) control ADSCs injected after 30 days; and (vi) TGF-β1 plus 5 × 10(5) ADSCs-IFN injected after 30 days. Rat allogeneic ADSCs were harvested from inguinal fat tissue.

MAIN OUTCOME MEASURES

Forty-five days following the TGF-β1 injection, erectile function was assessed, and penile tissues were harvested for further evaluations.

RESULTS

In the same-day injection groups, intratunical injection of ADSCs and ADSC-IFN improved erectile response observed upon stimulation of cavernous nerve compared with TAF group. Intratunical ADSC-IFN injection at day 30 improved erectile responses 3.1, 1.8, and 1.3 fold at voltages of 2.5, 5.0, and 7.0, respectively, when compared with TAF group. Furthermore, at voltages of 2.5 and 5.0, treatment on day 30 with ADSCs-IFN improved erectile responses 1.6- and 1.3-fold over treatment with ADSCs alone. Local injection of ADSCs or ADSCs-IFN reduced Peyronie's-like manifestations, and these effects might be associated with a decrease in the expression of tissue inhibitors of metalloproteinases.

CONCLUSION

This study documents that transplantation of genetically modified ADSCs, with or without human IFN α-2b, attenuated Peyronie's-like changes and enhanced erectile function in a rat model of TAF.

Surgical management of Peyronie's disease

Peyronie's disease (PD) has a significant impact on the quality of life of both patients and their partners due to the compromised sexual function and physical deformation resulting from the condition. PD is a connective tissue disorder marked by fibrotic healing of the tunica albuginea, leading to penile deformities including curvature, shortening, loss of girth, hourglass appearance, and hinging. Despite the multiple medical therapies available, surgery is the gold standard of treatment once the plaque has stabilized. We present a review of the disease process, preoperative evaluation, operative planning, surgical treatments with outcomes and complications, and nascent developments in surgical management and graft development. Options include tunical lengthening procedures, tunical shortening procedures, and penile prosthesis. Decision-making is governed by degree of curvature, erectile function, and associated penile deformities. In cases with curvature of less than 60-70 degrees, adequate penile length, and no hourglass deformity, patients are candidates for tunical shortening procedures. Patients with curvature greater than 60-70 degrees, penile hourglass or hinge-destabilizing deformities, and adequate erectile function should be counseled with regard to tunical lengthening procedures. Patients with poor preoperative erectile function should undergo inflatable penile prosthesis placement, with possible secondary straightening procedures. Technique selection should be based upon surgeon preference, expertise, and experience, as evidence does not necessarily support one procedure over another.

PEYRONIE'S DISEASE: A REVIEW OF ETIOLOGY, DIAGNOSIS, AND MANAGEMENT

Peyronie's Disease (PD) is a superficial fibrosing disorder of the penis resulting in plaque formation and penile deformity. Once considered rare, PD has more recently been found in up to 13% of men, and can negatively affect sexual and psychosocial function of both patients and their partners. While the etiology of PD is unclear, it is thought to result from an inciting traumatic event followed by aberrant fibrosis or dysregulated wound healing. The evaluation of men presenting with PD includes a detailed history and physical exam, focusing on the penis in both the flaccid and erect states. PD is often associated with erectile dysfunction (ED), as well as several other comorbidities. Laboratory testing is not needed to diagnose PD, although given the associations between PD and systemic diseases including hypogonadism, diabetes, and cardiovascular disease, screening and work-up for these conditions in men with PD may be warranted. Treatment modalities for PD are diverse and include oral, topical, intralesional, mechanical, and surgical therapies. Oral, topical, and mechanical therapies generally have little evidence supporting their efficacy. Several intralesional therapies, including interferon α2b and collagenase Clostridium hystiolyticum have demonstrated efficacy in the treatment of PD. Surgical treatment, indicated in men with significant, stable deformity, includes plication of the tunica albuginea, plaque incision/excision and grafting, and placement of inflatable penile prosthesis (IPP) with or without additional maneuvers to achieve desired results, and has high success rates.

Animal models of erectile dysfunction

Animal models have contributed to a great extent to understanding and advancement in the field of sexual medicine. Many current medical and surgical therapies in sexual medicine have been tried based on these animal models. Extensive literature search revealed that the compiled information is limited. In this review, we describe various experimental models of erectile dysfunction (ED) encompassing their procedures, variables of assessment, advantages and disadvantages. The search strategy consisted of review of PubMed based articles. We included original research work and certain review articles available in PubMed database. The search terms used were “ED and experimental models,” “ED and nervous stimulation,” “ED and cavernous nerve stimulation,” “ED and central stimulation,” “ED and diabetes mellitus,” “ED and ageing,” “ED and hypercholesteremia,” “ED and Peyronie's disease,” “radiation induced ED,” “telemetric recording,” “ED and mating test” and “ED and non-contact erection test.”

Adipose tissue-derived stem cell therapy for prevention and treatment of erectile dysfunction in a rat model of Peyronie's disease

Peyronie's disease (PD) is a localized connective tissue disorder that involves the tunica albuginea (TA) of the penis. While surgical correction remains the gold standard, the search for an effective and less invasive therapy continues. The objective of this study was to evaluate the effects of intratunical injection of adipose tissue-derived stem cells (ADSCs) for the prevention and treatment of erectile dysfunction in a rat model of PD. Twenty-four male Sprague-Dawley rats (300-350 g) were randomly divided into four groups: sham, PD, PD + ADSC (prevention) and PD + ADSC (treatment). All rats underwent penile injections into the TA with 50 μL vehicle (sham) or 0.5 μg transforming growth factor (TGF)-β1 (remaining groups). The ADSC groups received intratunical injections with 0.5 million rat-labelled ADSCs on day 0 (prevention) or day 30 (treatment). Forty-five days following TGF-β1 injection, rats underwent cavernous nerve stimulation (CNS) with total intracavernous-to-mean arterial pressure ratio (ICP/MAP) and total ICP recorded to measure response to therapy. Tissues were evaluated histologically and for mRNA expression of tissue inhibitors of metalloproteinases (TIMPs), matrix metalloproteinases (MMPs) and zymographic activity of MMPs. Statistical analysis was performed by analysis of variance followed by the Tukey test for post hoc comparisons. In both prevention and treatment groups, intratunical injection of ADSCs resulted in significantly higher ICP/MAP and total ICP in response to CNS compared with the PD group. Local injection of ADSCs prevented and/or reduced Peyronie's-like changes by decreasing the expression of TIMPs, and stimulating expression and activity of MMPs. This study documents the preventive and therapeutic benefits of ADSC on penile fibrosis and erectile function in an animal model of PD.

Evaluation of verapamil efficacy in Peyronie's disease comparing with pentoxifylline

INTRODUCTION

Peyronie's disease described as penile curvature, fibromathosis and pain that occur most often in men aged 40 to 60 years. The main complaint that caused the patient to visit the clinic is nodules on the upper surface of the penis, causing curvature and distortion particularly during erection, but they don't have any urinary problem. In this study, we evaluated the effect of verapamil compared to pentoxifylline in Peyronie's disease.

METHODS

In this study, 90 patients with signs and symptoms of Peyronie's disease which were diagnosed and were in the age range 40 to 70 years enrolled. The patients were randomly divided into 3 groups. First group received pentoxifylline orally at a dose of 400 mg three times a day, in the second group verapamil (10 mg every other week for up to 12 sessions) was injected into the lesion and the third group received both treatments in combination.

RESULTS

In patients, who received pentoxifylline, curvature reduction was 26.7%, plaque size reduction was 30%, the recovery rate of erectile dysfunction was 46.7% and pain reduced was 73.3%. Each of these cases in patients, who used beta-blockers, was 36.7%, 33.3%, 66.7% and 76.6%. In combination therapy, curvature reduction was 36.7%, plaque size reduction was 33.3%, the recovery rate of erectile dysfunction was 86.7% and pain reduced was 80%.

CONCLUSION

In our study there was no significant difference between two groups using verapamil or pentoxifylline, but there was a significant improvement in combination therapy group. Due to our results we propose that combination therapy can improve results and should be considered as a choice in treatment of Peyronie's disease. 

The pathophysiology of Peyronie's disease

OBJECTIVE

To review the contemporary knowledge of the pathophysiology of Peyronie's disease (PD).

METHODS

Medline was searched for papers published in English from 2000 to March 2013, using the keywords 'Peyronie's disease' and 'pathophysiology'.

RESULTS

More than 300 relevant articles were identified for the purpose of this review. Unfortunately only a few studies had a high level of evidence, and the remaining studies were not controlled in their design. Many theories have been proposed to explain the cause of PD, but the true pathogenesis of PD remains an enigma. Identifying particular growth factors and the specific genes responsible for the induction of PD have been the ultimate goal of research over the past several decades. This would provide the means to devise a possible gene therapy for this devastating condition. We discuss present controversies and new discoveries related to the pathophysiology of this condition.

CONCLUSION

PD is one of the most puzzling diseases in urology. The pathogenesis remains uncertain and there is still controversy about the best management. The pathogenesis of PD has been explored in animal models, cell cultures and clinical trials, but the results have led to further questions. New research on the aetiology and pathogenesis of PD is needed, and which will hopefully improve the understanding and management for patients with this frustrating disease.

A novel PI3K inhibitor alleviates fibrotic responses in fibroblasts derived from Peyronie's plaques

Peyronie's disease (PD) is fibrosis localized in the tunica albuginea that is characterized by penile deformity and curvature. The pathogenesis of this disease remains unclear even though transforming growth factor-β (TGF-β)/smad signalling has been reported to be associated with PD. Recent studies have shown that phosphoinositide 3-kinase (PI3K)/Akt signalling regulates fibrotic responses including collagen synthesis and cell proliferation. Thus, we synthesized HS-173, a novel PI3K inhibitor, and determined whether this compound has anti-fibrotic effects on PD-derived primary fibroblasts. In this study, we found that HS-173 inhibited the growth of fibroblasts in a dose-dependent manner and induced apoptosis. In addition, HS-173 reduced the expression of α-smooth muscle actin (α-SMA), vimentin, PAI-1, fibronectin, collagen type I, collagen IV and TGF-β-activated smad2/3 in PD-derived primary fibroblasts. HS-173 blocked the PI3K/Akt signalling pathway by decreasing the activation of Akt, mTOR and P70S6K. Our results showed that HS-173 suppressed fibrotic responses such as cell proliferation and collagen synthesis by blocking PI3K/Akt signalling in PD-derived primary fibroblasts. Our findings provide molecular insights into the potential therapeutic action of HS-173 through targeting the PI3K/Akt pathway in PD-derived fibroblasts and demonstrated that HS-173 could be used as a pharmacological agent for treating other fibrotic diseases.

Current and emerging treatment options for Peyronie's disease

Peyronie’s disease (PD) is a condition of the penis, characterized by the presence of localized fibrotic plaque in the tunica albuginea. PD is not an uncommon disorder, with recent epidemiologic studies documenting a prevalence of 3–9% of adult men affected. The actual prevalence of PD may be even higher. It is often associated with penile pain, anatomical deformities in the erect penis, and difficulty with intromission. As the definitive pathophysiology of PD has not been completely elucidated, further basic research is required to make progress in the understanding of this enigmatic condition. Similarly, research on effective therapies is limited. Currently, nonsurgical treatments are used for those men who are in the acute stage of PD, whereas surgical options are reserved for men with established PD who cannot successfully penetrate. Intralesional treatments are growing in clinical popularity as a minimally invasive approach in the initial treatment of PD. A surgical approach should be considered when men with PD do not respond to conservative, medical, or minimally invasive therapies for approximately 1 year and cannot have satisfactory sexual intercourse. As scientific breakthroughs in the understanding of the mechanisms of this disease process evolve, novel treatments for the many men suffering with PD are anticipated.

Surgery for Peyronie's disease

Peyronie's disease (PD) is most simply referred to as a fibrotic wound-healing disorder of the tunica albuginea. It is both a physically and psychologically devastating disorder that causes penile deformity, curvature, hinging, narrowing and shortening, which may compromise sexual function. Although a variety of non-surgical treatments have been suggested, none to date offer a reliable and effective correction of the penile deformity. As a result, surgery remains the gold standard treatment option, offering the most rapid and reliable treatment which will be the focus of this article. We review the preoperative evaluation, surgical algorithm, graft materials and postoperative management of PD. Outcomes for tunical shortening, tunical lengthening and penile prosthesis placement for penile straightening are reviewed. Tunica albuginea plication is the preferred method of straightening for men with adequate rigidity and less severe disease defined as curvature less than 70° without narrowing/hinging. Men who have more severe, complex deformity, but maintain strong preoperative erectile function should be considered candidates for straightening with plaque incision or partial excision and grafting. Finally, for those men who have inadequate rigidity and PD, penile prosthesis placement with straightening is the best approach to address both problems.

Intratunical injection of human adipose tissue-derived stem cells prevents fibrosis and is associated with improved erectile function in a rat model of Peyronie's disease

BACKGROUND

Peyronie's disease (PD) is a connective tissue disorder of the tunica albuginea (TA). Currently, no gold standard has been developed for the treatment of the disease in its active phase.

OBJECTIVE

To test the effects of a local injection of adipose tissue-derived stem cells (ADSCs) in the active phase of a rat model of PD on the subsequent development of fibrosis and elastosis of the TA and underlying erectile tissue.

DESIGN, SETTING, AND PARTICIPANTS

A total of 27 male 12-wk-old Sprague-Dawley rats were divided in three equal groups and underwent injection of vehicle (sham), 0.5-μg [corrected] transforming growth factor (TGF)-β1 in a 50-μl vehicle in either a PD or a PD plus ADSC group in the dorsal aspect of the TA.

INTERVENTION

The sham and PD groups were treated 1 d after TGF-β1 injection with intralesional treatment of vehicle, and the PD plus ADSC group received 1 million human-labeled ADSCs in the 50-μl vehicle. Five weeks after treatment, six rats per group underwent erectile function measurement. Following euthanasia, penises were harvested for histology and Western blot.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The ratio of intracavernous pressure to mean arterial pressure (ICP/MAP) upon cavernous nerve stimulation, elastin, and collagen III protein expression and histomorphometric analysis of the penis. Statistical analysis was performed by analysis of variance followed by the Tukey-Kramer test for post hoc comparisons or the Mann-Whitney test when applicable.

RESULTS AND LIMITATIONS

Erectile function significantly improved after ADSC treatment (ICP/MAP 0.37 in PD vs 0.59 in PD plus ADSC at 5-V stimulation; p=0.03). PD animals developed areas of fibrosis and elastosis with a significant upregulation of collagen III and elastin protein expression. These fibrotic changes were prevented by ADSC treatment.

CONCLUSIONS

This study is the first to test stem cell therapy in an animal model of PD. Injection of ADSCs into the TA during the active phase of PD prevents the formation of fibrosis and elastosis in the TA and corpus cavernosum.

Decorin as a new treatment alternative in Peyronie's disease: preliminary results in the rat model

The purpose of this study is to investigate the effect of decorin, a naturally occurring proteoglycan with anti-transforming growth factor beta (TGF-β) activity, on the rat model of Peyronie's disease (PD). Twenty-five adult male Sprague-Dawley rats were divided in three groups: I) TGF-β (0.5 μg) injected (n: 8); II) TGF-β injected and decorin treated (n: 8); and III) controls (n: 9). Decorin (0.5 μg per day) was given with intracavernous injection on the second, third, fourth and fifth day following TGF-β injection. All rats underwent electrical stimulation of the cavernous nerve after 6 weeks. Intracavernosal and arterial blood pressures were measured during this procedure. Cross-sections of the rat penises were examined using Mason trichrome and H&E stains. Statistical analyses were carried out using one-way anova. Histopathological examinations confirmed the Peyronie's-like condition in TGF-β-injected rats, which exhibited a thickening of the tunica albuginea (TA), when compared to controls. Disorganisation of collagen on the TA was also prominent in TGF-β-injected rats, but not in decorin-treated and control rats. Decorin-treated rats showed significantly higher maximal intracavernosal pressure (MIP) responses to cavernous nerve stimulation, when compared to group 1 (P < 0.05). Our results indicate that decorin antagonises the effects of TGF-β in the rat model of PD and prevents diminished erectile response to cavernous nerve stimulation.

Tissue engineering for penile surgery: comparative study of noncellular and cell-seeded synthetic grafts for tunica albuginea replacement

INTRODUCTION

Surgical treatment outcomes in Peyronie's disease remain controversial because of high rates of recurrence.

AIM

The aim of this study was to engineer in vitro a new type of tunica albuginea (TA) autologous graft obtained by culture of autologous fibroblast on a polyglycolic acid (PGA) scaffold. This engineering graft was compared with PGA with morphological and functional outcomes for TA replacement, 4 months after graft upon corpus cavernosum in a rat model.

METHODS

Thirty-nine Sprague Dawley adult male rats were divided into four groups: (i) control group (C) with resection and resuture of a 5 mm long and 2 mm large piece of original TA; (ii) PGA scaffold group (P) with the same resection of TA and suture of PGA scaffold; (iii) autologous fibroblast-seeded on PGA scaffold graft after resection of the same piece of TA (F + P); and (iv) sham group for functional and histological comparison.

MAIN OUTCOME MEASURE

The main outcome measure was assessment of graft size variation at 4 months and comparison between the three test groups. The secondary objective is assessment of erectile function by measuring erectile response to cavernous nerve electrical stimulation in each group.

RESULTS

At 4 months, there was a significant difference in graft area retraction between the groups (P = 0.0081) with higher retraction in P group vs. in C or F + P groups. Erectile response to cavernous nerve stimulation significantly differed between the groups and was sham equivalent to C equivalent to F + P superior to P group.

CONCLUSIONS

This study provides experimental evidence for the feasibility and the functionality of fibroblast-seeded scaffold compared with acellular graft for TA replacement.

Rat as an animal model for Peyronie's disease research: a review of current methods and the peer-reviewed literature

While the exact mechanism of Peyronie's disease (PD) remains an enigma, the pathophysiology of PD is considered to be multifactorial, with interactions of genetic predisposition, trauma, tissue inflammation and aberrant wound healing. A non-systematic review of the existing English language literature pertaining to the use of rodent models in the evaluation of PD was performed using the Medline database. Multiple free-text searches were performed on key words: animal models of PD, transforming growth factor β1 (TGF β1), tunical and/or corporal fibrosis, subtunical injection and penile myofibroblasts. The most frequently reported models of PD can be classified as TGF β1, fibrin and surgical trauma-induced models. In vitro studies using Peyronie's fibroblast culture media have also provided further insights into cellular mechanism of PD. At the present time, the research in PD is hampered by the lack of universally accepted animal model and this is likely attributed to the limited insight into PD mechanisms and the difficulties faced by current animal models to truly represent the complexity and complete spectrum of human disease.

Review of non-surgical treatment options for Peyronie's disease

Non-surgical treatment of Peyronie's disease (PD) has come a long way since it was first described in 1743. A myriad of treatment options are currently available, including oral, intralesional and external energy therapies. The purpose of this article is to review the contemporary literature on non-surgical therapies for PD, and where possible, focus on randomized, placebo-controlled trials, as well as review the latest guidelines for the management of PD from the International Committee on Sexual Medicine, which conveyed its findings in July 2009. At this time, it appears that a combination of oral agents and/or intralesional injection with traction therapy may provide a synergy between the chemical effects of the drugs and the mechanical effects of traction. Until a reliable treatment emerges, it does appear that some of the non-surgical treatments discussed can be used to stabilize the scarring process and may result in some reduction of deformity with improved sexual function.

Reversion of penile fibrosis: Current information and a new horizon

Ageing has a detrimental effect on cavernous tissue and the tunica albuginea of the penis. Furthermore, atherosclerosis of the penile vessels that occurs with ageing causes a decrease in penile oxygen tension. A reduction in smooth muscle cells (SMCs) was shown in relation to diminution of oxygen tension. Chronic ischaemia is therefore not only associated with fibrosis but also with nitric oxide-cyclic guanosine monophosphate reduction. The sensitivity of the α-adrenoceptors on the SMCs increases with ageing. The decrease in penile elasticity and compliance are explained by the changes in the ratio of penile collagen that occur with ageing. Contradictory to the view that testosterone is only necessary for sexual desire, numerous recent studies showed that androgen deprivation produces penile tissue atrophy, alterations in dorsal nerve structure, alterations in endothelial morphology, reduction in trabecular SM content, increase in deposition of extracellular matrix and accumulation of fat-containing cells (adipocytes) in the subtunical region of corpus cavernosum. The aim of the current review is to shed some light on the underlying aetiology of corporal fibrosis especially ageing, cavernous nerve damage, androgen deprivation and tunical fibrosis. Ultimately I will address the proposed prevention of erectile dysfunction associated with penile fibrosis.

Peyronie's disease: perspectives on therapeutic targets

INTRODUCTION

Peyronie's disease (PD) is an acquired benign connective tissue disorder of the penis, characterized by the development of fibrotic plaques, that can cause different degrees of bending, narrowing or shortening. Medical treatment for PD remains a major challenge. Impressive progress in our understanding of the molecular mechanisms of PD pathogenesis has uncovered several promising molecular targets for antifibrotic treatments.

AREAS COVERED

This review covers the literature pertaining to the exploration of therapeutic targets for PD. The search included: i) a MEDLINE search from 1941 to January 2011, limited to English-language medical literature, ii) relevant abstracts from 2009 and 2010, iii) relevant textbooks and iv) a pipeline search for therapeutics in development.

EXPERT OPINION

Rapid translational research depends on our ability to develop rational therapies targeted to penile tunical fibrosis, which necessitate a sound knowledge of the biology, biochemistry and the physiological role of fibroblasts, myofibroblasts and stem cells in PD. Much remains to be learned about the pathogenesis of PD. Although there are many interesting therapeutic targets, we are confronted with some questions when identifying new targets, or when validating potential therapeutic options.

The role of PDE5 inhibitors in penile septal scar remodeling: assessment of clinical and radiological outcomes

INTRODUCTION

Effective oral medication for use in men with Peyronie's disease (PD) has been an area of interest of the medical community and lay public for decades. Isolated septal scars (ISS) without evidence of penile deformity is a relatively new clinical entity, and at present, there is paucity in the published literature regarding its treatment. Current research into the use of phosphodiesterase type 5 (PDE5) inhibitors in regulating penile erectile response has revealed an alternative role for PDE5 inhibitors in decreasing oxidative stress-associated inflammatory change as seen in PD.

AIM

To examine the presence of ISS and assess the efficacy of PDE5 inhibitor use in septal scar remodeling.

METHODS

Retrospective review of prospective database on all men who underwent penile Doppler ultrasound between December 2007 and December 2009.

MAIN OUTCOME MEASURES

Of the 65 men with ultrasonographic-confirmed ISS, 35 men received tadalafil 2.5 mg daily over a 6-month period. The clinical outcomes between the two groups were compared using International Index of Erectile Function (IIEF)-5 score and 6 months penile Doppler ultrasound follow up.

RESULTS

The mean age for the tadalafil group was 43.2 (20-65) years, similar to the control group at 44.2 (34-72) years. The length of time from onset to presentation was 22 (6 to 40) months. The majority of ultrasonographic-proven ISS was not clinically palpable and complaint of decreased penile rigidity (66%) was the predominant feature. Treatment with low-dose daily tadalafil did not result in any significant side effects (such as headache and flushing) or discontinuation. The tadalafil group reported higher IIEF-5 score (pretreatment 11/25 to post-treatment 18/25) (P < 0.01) and resolution of septal scar were recorded in 24 patients (69%) compared to three patients (10%) in the control group.

CONCLUSION

Low-dose daily tadalafil is a safe and effective treatment option in septal scar remodeling.