Gene expression profiles in the Peyronie's disease plaque

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.

Unveiling the molecular Hallmarks of Peyronie's disease: a comprehensive narrative review

Peyronie's disease, a fibroinflammatory disorder, detrimentally impacts the sexual well-being of men and their partners. The manifestation of fibrotic plaques within penile tissue, attributed to dysregulated fibrogenesis, is pathognomonic for this condition. The onset of fibrosis hinges on the perturbation of the equilibrium between matrix metalloproteinases (MMPs), crucial enzymes governing the extracellular matrix, and tissue inhibitors of MMPs (TIMPs). In the context of Peyronie's disease, there is an elevation in TIMP levels coupled with a decline in MMP levels, culminating in fibrogenesis. Despite the scant molecular insights into fibrotic pathologies, particularly in the context of Peyronie's disease, a comprehensive literature search spanning 1995 to 2023, utilizing PubMed Library, was conducted to elucidate these mechanisms. The findings underscore the involvement of growth factors such as FGF and PDGF, and cytokines like IL-1 and IL-6, alongside PAI-1, PTX-3, HIF, and IgG4 in the fibrotic cascade. Given the tissue-specific modulation of fibrosis, comprehending the molecular underpinnings of penile fibrosis becomes imperative for the innovation of novel and efficacious therapies targeting Peyronie's disease. This review stands as a valuable resource for researchers and clinicians engaged in investigating the molecular basis of fibrotic diseases, offering guidance for advancements in understanding Peyronie's disease.

Molecular Mechanisms and Risk Factors Related to the Pathogenesis of Peyronie's Disease

Peyronie's disease (PD) is a benign condition caused by plaque formation on the tunica albuginea of the penis. It is associated with penile pain, curvature, and shortening, and contributes to erectile dysfunction, which worsens patient quality of life. In recent years, research into understanding of the detailed mechanisms and risk factors involved in the development of PD has been increasing. In this review, the pathological mechanisms and several closely related signaling pathways, including TGF-β, WNT/β-catenin, Hedgehog, YAP/TAZ, MAPK, ROCK, and PI3K/AKT, are described. Findings regarding cross-talk among these pathways are then discussed to elucidate the complicated cascade behind tunica albuginea fibrosis. Finally, various risk factors including the genes involved in the development of PD are presented and their association with the disease summarized. The purpose of this review is to provide a better understanding regarding the involvement of risk factors in the molecular mechanisms associated with PD pathogenesis, as well as to provide insight into disease prevention and novel therapeutic interventions.

Statins synergize with phosphodiesterase type 5 inhibitors but not with selective estrogen receptor modulators to prevent myofibroblast transformation in an in vitro model of Peyronie's disease

BACKGROUND

Peyronie's disease (PD) is a fibrotic disorder characterized by plaque formation in the tunica albuginea (TA) of the penis, and we have previously shown that inhibition of transformation of TA-derived fibroblasts to myofibroblasts using a combination phosphodiesterase type 5 (PDE5) inhibitors and selective estrogen receptor modulators (SERMs) is effective in slowing the progression of early PD.

AIM

The study sought to investigate whether combinations of statins with PDE5 inhibitors or SERMs would affect myofibroblast transformation in vitro.

METHODS

Primary fibroblasts were isolated from TA of patients with PD and stimulated with transforming growth factor β1 in the absence and presence of a range of concentrations of statins, PDE5 inhibitors, SERMs, and their combinations for 72 hours before quantifying α-smooth muscle actin using in-cell enzyme-linked immunosorbent assay.

OUTCOMES

The prevention of transforming growth factor β1-induced transformation of TA-derived fibroblasts to myofibroblasts was measured in vitro.

RESULTS

Statins (simvastatin, lovastatin) inhibited myofibroblast transformation in a concentration-dependent manner with half maximal inhibitory concentration values of 0.77 ± 0.07 μM and 0.8 ± 0.13 μM, respectively. Simvastatin inhibited myofibroblast transformation in a synergistic fashion when combined with vardenafil (a PDE5 inhibitor; log alpha >0). Combination of tamoxifen (a SERM) and simvastatin did not show synergy (log alpha <0). When 3 drugs (simvastatin, vardenafil, and tamoxifen) were combined, the effect was not synergistic, but rather was additive.

CLINICAL IMPLICATIONS

A combination of a statin with a PDE5 inhibitor might be useful in the clinic to slow the progression of the disease in patients with early PD; however, caution should be taken with such a combination because of the reported myopathy as a side effect.

STRENGTHS AND LIMITATIONS

The use of primary human cells from patients with PD is a strength of this study. The mechanisms by which these drug classes exert synergy when used in combination was not investigated.

CONCLUSION

This is the first demonstration of an antifibrotic synergy between statins and PDE5 inhibitors.

Significant inverse association of testosterone level with penile deformity severity in Japanese males with Peyronie's disease

OBJECTIVES

We evaluated the relationship between penile curvature and testosterone in Peyronie's disease patients treated in Japan.

METHODS

Data were obtained from 109 patients with Peyronie's disease treated with surgery at our hospital between April 2004 and December 2019. Penile deformity assessment was based on findings of a rigid erection induced by intracavernosal injection. Low total testosterone level was defined as <300 ng/dl. Patients were divided into two groups according to curvature severity (I, <60°; II ≥60°), then clinical factors including total testosterone were compared. Uni- and multivariate logistic regression analyses were performed to identify factors predicting severe penile deformity (≥60°).

RESULTS

For all patients, mean total testosterone was 469 ng/dl and median curvature was 50°, with a significant inverse correlation found between curvature and testosterone level (p < 0.0001). Group I and II patients numbered 55 and 54, respectively. Mean total testosterone for Group II was 397 ng/dl, significantly lower than Group I (539 ng/dl). Median curvature in 15 patients with a low testosterone level was 80°, significantly higher than those with a normal testosterone range (50°). Univariable and multivariable logistic regression analysis indicated total testosterone, follicle stimulating hormone, and C-reactive protein as significant factors correlated with severe penile deformity, among which total testosterone was most relevant.

CONCLUSION

The present findings confirmed that penile deformity severity is correlated with testosterone level in Japanese males with Peyronie's disease.

Identifying hub genes, key pathways and key immune-related genes in Peyronie's disease by integrated bioinformatic analysis

Scarring diseases, such as Peyronie's disease (PD), usually lead to disorders in the immune system. Previous studies suggested that the PD process was regulated by immune signaling. However, the pathogenetic mechanism remains incompletely characterized. This article used bioinformatic approaches to identify hub genes, key pathways and key immune-related genes that play essential roles in PD pathogenesis. Two Gene Expression Omnibus (GEO) datasets, GSE126005 and GSE146500, were used to analyse the transcriptional profiling in both PD and normal samples. R software was applied to examine the difference in the expression of hub genes and key immune-related genes. The candidates for hub genes were further validated through protein-protein interactions (PPIs), gene correlation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. In addition, candidate miRNA‒mRNA pairs were functionally assessed. A total of 39 candidate genes were identified, the expression levels of which in PD fibroblast cells were different from those in normal cells (16 showed reduced expression in PD and 21 candidates overexpressed in PD). We found that these genes could interact with each other through PPI analysis. According to the functional enrichment analysis, the candidates may regulate some major biological processes, including cytokine‒cytokine receptor interactions and the JAK-STAT signaling pathway. IL6, IL21R, IFNE, CXCL2, EGF, and ANGPTL5 were identified as key immune-related genes. The findings may help understand the role of immunologic contributors in PD, thus shedding light on the development of more effective strategies to prevent and treat this kind of disease.

Significant familial clustering of Peyronie's disease in close and distant relatives

BACKGROUND

Peyronie's disease (PD) has previously been observed to co-aggregate in a small number of first-degree relative pairs (e.g., father-son). However, the familial aggregation of PD in more distant relatives, as well as the aggregation of Dupuytren's disease (DD) in probands and relatives, has not been thoroughly investigated.

OBJECTIVE

This study explored the evidence for familial clustering of PD and DD in close and distant relatives.

MATERIALS AND METHODS

The Utah Population Database, which includes genealogy information linked to electronic medical records (available since 1995), was used to identify men and their relatives with PD and DD based on ICD9/10 codes. All cases were required to have high-quality genealogy data. We estimated relative risk (RR) of PD and DD in first- through fifth-degree relatives compared to matched population rates of disease. We also investigated the average relatedness of cases compared to the average relatedness of sets of matched controls. Outcome measures include estimation of relative risk and excessive relatedness as measured by a Genealogical Index of Familiality (GIF) analysis.

RESULTS

We analyzed 307 individuals with PD, and their first- through fifth-degree relatives. Approximately 0.12% of the population had PD, 95% of these were diagnosed over the age of 30 years (age range: 10-92 years), and 1.3% of PD probands had a comorbid diagnosis of DD. RR estimates for PD were significant for first- and fifth-degree relatives. RR estimates for DD were significant only for probands. The average relatedness of cases was significantly greater than matched controls, even after removing first- and second-degree relatives. We also found that 74.9% of identified PD probands belonged to pedigrees with a statistical excess of PD.

CONCLUSION

Despite the low prevalence of PD in our healthcare records, the results provide evidence that support a genetic contribution to at least a subset of PD cases.

Intratunical injection of rat-derived bone marrow mesenchymal stem cells prevents fibrosis and is associated with increased Smad7 expression in a rat model of Peyronie's disease

Objective

Peyronie’s disease (PD) is a fibrotic disorder of the penis, but effective treatments are lacking. Here, we observed the effects of rat-derived bone marrow mesenchymal stem cells (BMSCs) injection in the active phase and chronic phase in a rat model of PD, and the possible mechanism was analysed with fibroblasts derived from rat penile tunica albuginea (TA).

Methods

Thirty-two male Sprague-Dawley rats were divided into four groups. In sham group, the rats were injected with 50 µL of vehicle. In the PD group, the rats were injected with 50 µg TGF-β1. In the PD + BMSCs early treatment group, the rats were injected with 50 µg TGF-β1 and injected with 1 × 10⁶ BMSCs after 1 day. In the PD + BMSCs late treatment group, the rats were injected with 50 µg TGF-β1 and injected with 1 × 10⁶ BMSCs after 28 days. Twenty-seven days after the last injection, the erectile function of the rats was measured, and then, penile fibrosis was analysed by histology and western blot. In vitro, fibroblasts derived from rat penile TA were used to identify a possible antifibrotic mechanism of BMSCs, and a Smad7 expression vector was used as a positive control. Fibroblasts were pretreated with the Smad7 expression vector or BMSCs for 48 h and then activated with 10 ng/mL TGF-β1 for 24 h. Cells viability was assessed, and Smad7, collagen 3, elastase-2B and osteopontin expression levels were analysed by immunofluorescence and western blot. Furthermore, fibroblasts were transfected with Smad7 siRNA or scramble control to observe whether the effects of BMSCs could be offset.

Results

Erectile function obviously improved, and fibrosis of penile TA was prevented after BMSCs treatment compared with that in the rats with PD. Furthermore, the effects of BMSCs treatment in the active phase were better than those in the chronic phase. After cocultured with BMSCs, cell viability was not affected, Smad7 expression was upregulated, and collagen 3, elastase-2B and osteopontin levels were decreased in the TGF-β1-treated fibroblasts. After transfection with Smad7 siRNA, the antifibrotic effects of BMSCs were offset.

Conclusions

The antifibrotic effects of BMSCs treatment in the active phase of the PD rat model were better than those in the chronic phase. A possible mechanism of BMSCs treatment was related to increased Smad7 expression, suggesting a possible effective and safe procedure for the treatment of PD.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-03090-w.

Single-cell Transcriptomics Uncover a Novel Role of Myeloid Cells and T-lymphocytes in the Fibrotic Microenvironment in Peyronie's Disease

BACKGROUND

Peyronie's disease (PD) is an acquired fibrotic disease affecting the penile tunica albuginea that can lead to curvature and deformities, shortening, and erectile dysfunction. Although immunological mechanisms have been suggested for the pathophysiology of PD, these have not been investigated using single-cell transcriptomics.

OBJECTIVE

To investigate the immunological signature of plaques from PD patients using immunohistochemistry (IHC) and single-cell RNA sequencing (scRNA-Seq).

DESIGN, SETTING, AND PARTICIPANTS

Tunica albuginea biopsy was performed in patients undergoing penile surgery for either PD (n = 12) or plication or penile cancer (control, n = 6). The inclusion criteria for PD patients were stable chronic disease (≥12 mo in duration) and no previous penile surgery or intralesional injection therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

IHC was performed on surgical samples from ten patients with PD and five control subjects. An additional two PD and one control sample were used for scRNA-Seq (droplet-based; 10X Genomics). Cell clusters were visualised using heatmaps and t-distributed stochastic neighbour embedding plots (BioTuring v2.7.5).

RESULTS AND LIMITATIONS

IHC revealed the presence of myeloid dendritic cells (DCs; CD68⁺, TLR4⁺, CD206⁺), cytotoxic T lymphocytes (CTLs; CD3⁺, CD8⁺), and B lymphocytes (CD20⁺) in PD plaques, which were absent in controls. scRNA-Seq yielded results for 3312 PD and 5658 control cells. Cell clusters contained fibroblasts (COL1A2⁺), myofibroblasts (COL1A2⁺, ACTA2⁺), smooth muscle cells (ACTA2⁺, DES⁺), endothelial cells (VWF⁺), myeloid cells (CD14⁺), T lymphocytes (CD3D⁺), and neutrophils (ALPL⁺). Myeloid cell subclustering showed infiltration of monocyte-derived cells; control tissue contained classical DCs and resident macrophages. Lymphocyte subclustering revealed mucosal-associated invariant T (MAIT) cells and CTLs in PD. Differential gene expression suggests an increase in inflammatory and immune responses in chronic PD. The study is limited by the small scRNA-seq sample size (n = 3) for IHC, mitigated by a larger cohort of historic paraffin-embedded samples (n = 15), which showed largely parallel findings. Owing to tissue stiffness and extracellular matrix adhesion, our single-cell yield was lower for PD than for the control sample.

CONCLUSIONS

Our data suggest that even in the chronic PD stage (painless and stable curvature) there is a sustained inflammatory reaction. While vascularisation and collagen production are elevated, the inflammation is driven by specialised monocyte-derived CTL and MAIT cells. These findings could uncover new avenues for medical treatment of PD.

PATIENT SUMMARY

We looked at the role of the immune system in patients suffering from Peyronie's disease, a condition causing shortening and curvature of the penis. We found that even in a stable, chronic stage of the disease, there is activation of the immune system. Our results suggest that there is potential for novel treatments for this condition.

Implications of Calcification in Peyronie's Disease, A Review of the Literature

A common characteristic of Peyronie's Disease (PD) is plaque calcification, which is associated with decreased response to treatments and higher rates of surgical intervention. Despite its prevalence in the PD population, the literature on plaque calcification is limited. While the diagnosis of PD is mostly clinical, imaging modalities such as ultrasound can be used to identify plaque calcification. The proper identification of plaque calcification is crucial for guiding management and setting therapeutic expectations for patients with PD. Herein we discuss what is known about PD plaque calcification, including epidemiology, etiology, diagnosis, and management.

The Natural History of Peyronie's Disease

Peyronie's disease (PD), a fibrotic disorder of the tunica albuginea fully described in 1793 by French physician Francois de la Peyronie, is characterized by pain, plaque formation, penile deformity, and ultimately sexual function decline. The epidemiological data on PD vary considerably across previous studies, with recent evidence reporting a prevalence of up to 9%. PD is generally divided into two different phases: active or acute and stable or chronic. Plaque formation generally occurs during the acute phase, while during chronic phase pain usually tends to complete resolution and penile deformity stabilizes. PD's pathophysiology is still subject of great discussion. Tunical mechanical stress and microvascular trauma are major contributory factors. However, better understanding of the molecular pathophysiology of this condition remains paramount towards an in-depth comprehension of the disorder and the development of newer and more effective disease-targeted interventions. In this review we provide a detailed overview of natural history of PD, specifically focusing on clinical manifestations and the underlying molecular regulation patterns.

Peyronie's disease: is it genetic or not?

Peyronie's disease (PD) is a devastating disease that affects up to 13% of adult men. While trauma to the erect penis is common prior to onset, it is clear that trauma alone is not sufficient to cause PD. Over the past 40 years, multiple lines of evidence have pointed to a genetic factor that predisposes some men to develop PD. Despite dramatic technological advances in the field of genetics, we have made little progress in identifying the genetic contributors to the disease. This review will critically evaluate the literature concerning the genetics of PD published to date. Particular focus will be placed on study design as much of the data are contradictory yet may still give some insight into the etiology of PD. The challenges in identifying the genetic underpinnings of PD will be discussed along with the potential mechanisms that can overcome these challenges.

The Etiology of Peyronie's Disease: Pathogenesis and Genetic Contributions

INTRODUCTION

Peyronie's disease (PD) is a chronic fibrosing condition that contributes to penile deformity, curvature, and pain. Initial familial studies demonstrated potential genetic links to PD. Since that time, very few investigations have significantly advanced the science in this area. Hence, there is a large opportunity and significant need to better study the underlying genomics and pathogenesis of PD.

AIM

To summarize the current genomic literature relevant to PD.

METHODS

A review was performed of all PubMed-indexed literature from 1970-2018 relating to the pathophysiology and genetics of PD. Key findings were categorically summarized to include epidemiology, risk factors, inheritance patterns, chromosomal instability, genetic associations, epigenetics, differential gene expression, and preclinical models of PD.

MAIN OUTCOME MEASURES

Summary of the current literature on the genetics of PD.

RESULTS

PD is a common condition and has several known risk factors and comorbid disease associations. Although men with PD are believed to be genetically predisposed, there are likely several subtypes of the condition, each with varied pathophysiological disorders and contributing factors. Available data suggest that PD is associated with underlying genetic instability, including dysregulation of genes relating to fibrosis and cellular degradation, thus, resulting in abnormal plaque development and penile deformity. Preclinical models, including cell cultures and rat models, demonstrate several consistencies with PD clinical and histopathologic characteristics; however, an ideal model with spontaneous development of PD is lacking.

CONCLUSION

Based on limited data, PD likely represents a heterogeneous condition, with both heritable and environmentally-driven epigenetic factors contributing to its development and progression. However, there remains a significant gap in the literature on the underlying cause and pathophysiology of the condition, suggesting a substantial need for further investigation and study. Sharma KL, Alom M, Trost L. The Etiology of Peyronie's Disease: Pathogenesis and Genetic Contributions. Sex Med Rev 2020;8:314-323.

Inhibition of penile tunica albuginea myofibroblasts activity by adipose-derived stem cells

The activation of tunica albuginea myofibroblasts (MFs) serves an essential role in Peyronie's disease (PD). Increasing evidence has reported that adipose tissue-derived stem cells (ADSCs) have been demonstrated to attenuate the symptoms of PD in animal models. However, the mechanisms of the antifibrotic effects of ADSCs in PD remain to be fully elucidated. In the present study, the inhibitory effects and possible mechanism of ADSCs on the activation of MFs derived from rat penile tunica albuginea were investigated. ADSCs were obtained from the paratesticular fat of Sprague Dawley rats. MFs were transformed from rat penile tunica albuginea fibroblasts through stimulation with 5 ng/ml tumor growth factor-β1. Transwell cell cultures were adopted for co-culture of ADSCs and MFs. Western blot analysis was used to assess changes in the expression levels of α smooth muscle actin (αSMA), collagen I, phosphorylated (p)-SMAD family member 2 (Smad2), Smad2, ras homolog family member A (RhoA), Rho associated coiled-coil containing protein kinase (ROCK)1 and ROCK2, caspase3, caspase9, and matrix metalloproteinases (MMPs). Collagen gel assays were used to assess cell contractility. Additionally, the concentration of hydroxyproline in the culture medium was detected using commercially available kits. It was demonstrated that ADSCs reduced the expression of αSMA and collagen I of MFs. Furthermore, p-Smad2, RhoA, ROCK1 and ROCK2 expression was significantly reduced in the MFs+ADSCs group compared with that in the MFs-only culture, while the expression of MMPs (MMP2, MMP3, MMP9 and MMP13) and caspases (caspase3 and caspase9) was upregulated. In addition, ADSCs were able to downregulate the concentration of hydroxyproline in the culture medium of MFs and reverse the contraction of MFs. Collectively, these results suggested that ADSCs inhibited the activation of MFs, decreased collagen production, and suppressed the contraction of myofibroblasts, via Smad and RhoA/ROCK signaling pathways. Furthermore, ADSCs reduced the deposition of collagen and promoted the apoptosis of MFs via MMPs, and caspases. Accordingly, the application of ADSCs may provide a novel therapeutic strategy for PD.

Evidence-Based Management Guidelines on Peyronie's Disease

INTRODUCTION

Despite recent advances in our knowledge and treatment strategies in Peyronie's Disease (PD), much remained unknown about this disease.

AIM

To provide a clinical framework and key guideline statements to assist clinicians in an evidence-based management of PD.

METHODS

A systematic literature search was conducted to identify published literature relevant to PD. The search included all relevant articles published up to June 2015, including preclinical studies and published guidelines. References used in the text were assessed according to their level of evidence, and guideline recommendations were graded based on the Oxford Centre for Evidence-Based Medicine Levels of Evidence. Owing to the paucity of larger series and randomized placebo-controlled trials with regard to surgical intervention, guideline statements are provided as clinical principle or expert opinion.

MAIN OUTCOME MEASURES

This literature was discussed at a panel meeting, and selected articles with the highest evidence available were used to create consensus guideline statements for the Fourth International Consultation on Sexual Medicine guidelines on PD.

RESULTS

In addition to existing Third International Consultation on Sexual Medicine guidelines on PD, seven new summary recommendations were created.

CONCLUSION

A greater understanding of the scientific basis of PD is greatly needed to address our understanding of the pathophysiology, clinical epidemiology, psychosocial, and diagnostic assessment as well as treatment strategies.

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.

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.

Efficacy and safety evaluation of pentoxifylline associated with other antioxidants in medical treatment of Peyronie's disease: a case-control study

Peyronie's disease (PD) is a chronic disorder involving the tunica albuginea surrounding the corpora cavernosa of the penis. A conservative treatment is indicated in the first stage of disease. The aim of this study was to assess the therapeutic impact and possible side effects of treatment with pentoxifylline (PTX) in combination with other antioxidants in 307 patients with early-stage PD. Patients were subdivided into three groups: A, B, and C. Both groups, A and B, comprising of 206 patients, underwent treatment, whereas Group C was the control group (n=101). Treatment lasted 6 months and included the following: Group A: PTX 400 mg twice a day + propolis 600 mg/d + blueberry 160 mg/d + vitamin E 600 mg/d + diclofenac 4% gel twice/a day + PTX 100 mg via perilesional penile injection/every other week (12 injections in all); Group B: the same treatment as Group A except for the penile PTX injections. After the 6-month treatment course, we obtained the following results: actual mean decrease in plaque volume -46.9% and -24.8% in Group A and B, respectively (P<0.0001); mean curvature reduction -10.1° and -4.8°, respectively (P,0.0001); resolution of pain in 67.6% and 67.2% of cases, respectively (P=0.961); recovery of normal penile rigidity in 56.09% and 23.5% of cases, respectively (P=0.005). After 6 months, progression of disease was observed in all patients belonging to Group C: plaque volume +123.3%; curvature +15.7°; no recovery of penile rigidity. The statistically significant results of our study show that multimodal treatment with PTX in association with other antioxidants and topical diclofenac is efficacious in treating early-stage PD. Furthermore, treatment proved to be more effective when PTX was administered both orally and by penile injection. No serious adverse effects occurred.

The History of Collagenase Clostridium Histolyticum

INTRODUCTION

After its U.S. FDA approval in 2013, Collagenase Clostridium histolyticum (CCh) has seen increasing use as a nonoperative treatment for Peyronie's disease (PD). We review the history of CCh and trials that led to its adoption.

AIM

To provide a historical and contemporary context for the evolution of Collagenase Clostridium histolyticum as a treatment modality for Peyronie's disease.

METHODS

A comprehensive search of peer-reviewed literature was performed pertaining to CCh and its biochemical and clinical significance.

MAIN OUTCOME MEASURE

The main outcome studied was the efficacy and safety profile of CCh in PD. CCh use in other diseases processes and its associated outcomes are also described.

RESULTS

CCh injection yields objective improvement in penile curvature across multiple trials in PD patients. Recently, level 1 strength of evidence has emerged supporting its widespread use. As such, CCh stands as the only FDA-approved injectable therapy for PD. Adverse events were namely limited to local reactions. Serious systemic complications and need for intervention were rare.

CONCLUSIONS

CCh is a safe and effective treatment for PD patients with deformities and plaque configuration amenable to injectable therapy. Multiple trials have demonstrated improvements in objective and subjective metrics such as penile curvature and bother scores. However, multiyear follow-up is needed to assess durability and its sustained clinical significance. Currently, refinement in dosing and technique has established a niche for CCh in PD patients who are affected by their symptoms but are not yet committed to surgical intervention. Yang KK and Bennett N. The history of collagenase clostridium histolyticum.

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.

Pharmacologic therapy for Peyronie's disease: what should we prescribe?

INTRODUCTION

Peyronie's disease (PD) is a wound healing disorder of the penis with a myriad of proposed treatment options reported in the literature. Evaluating the available data and therapeutic management of PD can be challenging and confusing, even for the most experienced treating physician. This review provides a comprehensive overview of pharmacologic treatment options for PD, focusing on the best available evidence.

AREAS COVERED

A comprehensive literature search for published articles evaluating oral, topical, and injectable pharmacologic agents for PD was completed. Prospective, controlled trials were given precedence for inclusion.

EXPERT OPINION

Although a multitude of oral agents have been proposed and evaluated in PD patients, results vary widely and a reproducible objective benefit has not yet been strongly established for any single oral agent. Well-designed, large-scale, randomized controlled trials evaluating oral agents in PD patients are lacking. Consistent objective benefit from injectable agents has been supported for years by various non-controlled trials. Recently, injectable collagenase Clostridium histolyticum became the first pharmacologic agent to obtain FDA approval for use in PD patients, supported by data from a large-scale, Phase III randomized controlled trial. Further elucidation of the genetic and mechanistic pathways involved in the development and progression of PD will help define future therapeutic targets.

The transcriptional signatures of cells from the human Peyronie's disease plaque and the ability of these cells to generate a plaque in a rat model suggest potential therapeutic targets

INTRODUCTION

The success of medical therapies for Peyronie's disease (PD) has not been optimal, possibly because many of them went directly to clinical application without sufficient preclinical scientific research. Previous studies revealed cellular and molecular pathways involved in the formation of the PD plaque and in particular the role of the myofibroblast.

AIMS

The current work aimed to determine under normal and fibrotic conditions what differentiates PD cells from tunica albuginea (TA) and corpora cavernosa (CC) cells by defining their global transcriptional signatures and testing in vivo whether PD cells can generate a PD-like plaque.

METHODS

Human TA, PD, and CC cells were grown with transforming growth factor beta 1 (TGFβ1; TA+, PD+, CC+) or without it (TA-, PD-, CC-) and assayed by (i) immunofluorescence, Western blot and RT-PCR for myofibroblast, smooth muscle cell and stem cell markers; (ii) collagen content; and (iii) DNA microarray analysis. The ability of PD+ cells to induce a PD-like plaque in an immuno-suppressed rat model was assessed by Masson trichrome and Picrosirius Red stainings.

MAIN OUTCOMES MEASURES

Fibroproliferative features of PD cells and identification of related key genes as novel targets to reduce plaque size.

RESULTS

Upon TGFβ1stimulation, collagen levels were increased by myofibroblasts in the PD+ but not in the CC+ cells. The transcriptional signature of the PD- cells identified fibroproliferative, myogenic (myofibroblasts), inflammatory, and collagen turnover genes that differentiate them from TA- or CC- cells and respond to TGFβ1 with a PD+ fibrotic phenotype, by upregulation of IGF-1, ACTG2, MYF5, ACTC1, PSTN, COL III, MMP3, and others. The PD+ cells injected into the TA of the rat induce a PD-like plaque.

CONCLUSIONS

This suggests a novel combination therapy to eliminate a PD plaque by targeting the identified genes to (i) improve collagenase action by stimulating endogenous metalloproteinases specific to key collagen types and (ii) counteract fibromatosis by inhibiting myofibroblast generation, proliferation, and/or apoptosis.

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 relationship between androgens, regulators of collagen metabolism, and Peyronie's disease: a case control study

INTRODUCTION

Changes in collagen metabolism have been postulated to play a pivotal role in the pathogenesis of Peyronie's Disease (PD). Androgens such as dehydroepiandrosterone sulfate (DHEA-S) and testosterone influence collagen metabolism by modulating the activity of matrix metalloproteases (MMP) and tissue inhibitors of metalloproteases (TIMP).

AIM

The aim of this study was to evaluate the interrelationship between androgens (DHEA-S and testosterone), key regulators of collagen metabolism such as insulin-like growth factor (IGF) 1 and IGF Binding Protein 3 (IGF-BP3), the MMP/TIMP system, and PD.

METHODS

Age matched PD patients (14) and healthy men (10) who acted as controls were recruited. Blood samples were collected from all subjects in the early morning hours after an overnight fast.

MAIN OUTCOME MEASURES

Serum levels of testosterone, sex hormone binding globulin, DHEA-S, 3-α-androstanediol glucuronide, pro-MMP-1, MMP-1, MMP-2, TIMP-1, TIMP-2, IGF-1 and IGF-BP3 were measured in both groups. Statistical methods included univariate, bivariate, and multivariate regression models.

RESULTS

Levels of DHEA-S (114.5 vs. 169.5 µg/dL; p = 0.03), IGF-BP3 (2.96 vs. 3.79 µg/mL; p = 0.01), and TIMP-1 (173.1 vs. 195 ng/mL; p = 0.01) were significantly lower in PD patients. In contrast, the level of TIMP-2 (102 vs. 85 ng/mL; p = 0.001) was significantly lower in the control group. Using stepwise regression analysis, only TIMP-2 (p < 0.001) and DHEA-S (p = 0.04) were significantly related to PD in the final model (R(2) = 0.63). TIMP-1 and DHEA-S (r = 0.55, p < 0.05) were positively correlated in the PD group, whereas IGF-1 and testosterone (r = -0.54, p < 0.05), and IGF-BP3 and testosterone (r = -0.68, p < 0.05) were negatively correlated in PD patients.

CONCLUSIONS

Our findings suggest that decreased levels of adrenal androgens may be implicated in the pathogenesis of PD. The mechanism and clinical relevance of this observation remain to be established.

The management of Peyronie's disease: evidence-based 2010 guidelines

INTRODUCTION

The field of Peyronie's disease is evolving and there is need for a state-of-the-art information in this area.

AIM

To develop an evidence-based state-of-the-art consensus report on the management of Peyronie's disease.

METHODS

To provide state-of-the-art knowledge regarding the prevalence, etiology, medical and surgical management of Peyronie's Disease, representing the opinion of leading experts developed in a consensus process over a 2-year period.

MAIN OUTCOME MEASURES

Expert opinion was based on grading of evidence-based medical literature, widespread internal committee discussion, public presentation, and debate.

CONCLUSIONS

The real etiology of Peyronie's disease and the mechanisms of formation of the plaque still remain obscure. Although conservative management is obtaining a progressively larger consensus among the experts, surgical correction still remains the mainstay treatment for this condition.

Experimental models of Peyronie's disease. Implications for new therapies

INTRODUCTION

Despite its high prevalence and impact on the quality of life of patients, and that it is an excellent model for the study of fibrotic processes, Peyronie's disease (PD) is an orphan disease in biomedical research. The development of animal and cell culture models has advanced substantially the understanding of its molecular and cellular pathology and the proposal of new therapies.

AIM

To review the literature pertaining to the use of these models for the study of PD.

METHODS

PubMed search conducted from the first report of an animal model for PD.

RESULTS

This model, based on the finding that transforming growth factor beta1 (TGF beta 1) is overexpressed in the PD plaque, consists on the injection of TGF beta 1 into the tunica albuginea of the rat. This leads to a PD-like plaque retaining many of the histological and biochemical features of human PD. Another rat model, based on the hypothesis that the PD plaque arises from trauma to the penis, causing fibrinogen extravasation that initiates as fibrin a fibrotic response, consists on injection of fibrin into the tunica. The cell culture model is based on the demonstration that myofibroblasts are abundant in the human PD plaque.

CONCLUSIONS

These models have: (i) clarified the role of microtrauma, myofibroblasts, and oxidative stress in plaque development; (ii) demonstrated that this tissue is under sustained turnover by fibrotic and antifibrotic mechanisms; (iii) showed the interplay of collagenolytic and fibrinolytic systems and their inhibitors; (iv) detected an endogenous antifibrotic process consisting of the expression of inducible nitric oxide synthase that counteracts oxidative stress, collagen synthesis, and myofibroblast generation; (v) characterized the antifibrotic effects of chronic treatment with phosphodiesterase type 5 (PDE5) inhibitors; (vi) discovered the cytogenetic instability of PD cells and alterations in their gene expression; and (vii) detected stem cells in the tunica albuginea with a potential role in fibrosis and ossification.

Is There a Role for Proteomics in Peyronie's Disease?

INTRODUCTION

Peyronie's disease (PD) continues to be a major source of sexual dysfunction among the 3-9% of affected men. The challenge in treating PD is determining the natural history and clinical course for the individual patient. Currently, there exists no reliable means to predict whether a penile plaque of PD will progress, regress, or remain stable. This represents a significant deficiency in contemporary management, one that may be addressed with newer technologies such as proteomic profiling.

AIM

This review assesses the potential use of protein alterations measured by various novel technologies, to predict progression, regression, or stabilization of PD in an affected individual.

METHODS

A comprehensive literature review of the past decade in the field of gene profiling and protein expression of PD was performed.

MAIN OUTCOME MEASURES

A critical analysis of the existing worldwide literature evaluating surface-enhanced laser desorption/ionization time of flight mass spectrometry (SELDI-TOF-MS or SELDI) and other proteonomic techniques.

RESULTS

SELDI and other technologies can provide the clinician with innovative data indicating the presence of unique individual factors that act to suppress or promote the fibrotic process in PD. Determining the clinical implications of altered protein expression in an individual is not yet defined.

CONCLUSIONS

The area of proteomics has begun to revolutionize the study of medicine in the postgenomic era, by allowing researchers to study the role that proteins play in health and disease. Applying this knowledge clinically has already led to innovative discoveries in early cancer detection in a number of malignancies, including prostate, ovarian, and bladder. Prior to the widespread use and acceptance of proteomic technology in PD, a critical assessment of its therapeutic and diagnostic value will be required.

Isolated Septal Fibrosis or Hematoma—Atypical Peyronie’s Disease?

PURPOSE

Classically Peyronie's disease presents with penile curvature and/or pain, and is associated with a palpable penile plaque. We frequently examine patients with suspected Peyronie's disease ultrasonographically and have noted a subset of patients in whom we could identify only a circumscribed septal lesion. We identified characteristics of these patients.

MATERIALS AND METHODS

Of our series of approximately 650 patients with Peyronie's disease 47 were identified with these lesions.

RESULTS

Of the 47 patients 22 presented with penile curvature with or without accompanying or preceding pain. Of the 47 patients 17 had a significant history of trauma, although only had the classic stigmata of penile fracture. A total of 16 patients had no history of curvature, 7 presented with only penile shortening or focal lack of rigidity and 5 were incidentally found to have lesions during assessment for other complaints. Three patients presenting after trauma were noted to have septal liquefied hematomas, which we aspirated under ultrasound guidance. Followup ultrasound revealed minimal septal thickening. In 1 of these patients the hematoma was adjacent to more typical-appearing septal fibrosis.

CONCLUSIONS

We theorize that these hematomas are due to septal fractures and may represent a forme fruste or possibly a precursor lesion of more typical septal fibrosis. Ultrasonographic evaluation may allow earlier identification and treatment of occult septal injuries or lesions and prevent subsequent fibrosis and its associated symptoms.

Pharmacological Management of Peyronie???s Disease

Peyronie's disease is a localised, fibrosing condition of the penis that occurs in up to 9% of men. Although its aetiology has not been elucidated, Peyronie's disease probably results from the presence of a predisposing genetic susceptibility combined with an inciting event, most probably trauma. Following appropriate clinical evaluation, initial treatment consists of a trial of oral and/or intralesional pharmacotherapy. Oral therapies most commonly employed include para-aminobenzoate (Potaba) and tocopherol (vitamin E), with colchicine, tamoxifen, propoleum and acetyl-L-carnitine being used less frequently. Placebo-controlled studies examining these agents have failed to show a consistent beneficial effect on Peyronie's disease, with the exception of para-aminobenzoate, which may decrease plaque size and curvature, and acetyl-L-carnitine, which may reduce erectile pain and inhibit disease progression. Intralesional injection therapy for Peyronie's disease is commonly used as a first-line therapy along with oral medications. The current standard of care involves injection with interferon-alpha-2a or -2b, verapamil or collagenase over 2-week intervals for a period of 5-6 months. Interferon-alpha-2b, in particular, has been documented in a large, multicentre, placebo-controlled study to be significantly more effective than placebo in decreasing penile curvature, plaque size, penile pain and plaque density. However, interferon treatment is also associated with significant adverse effects, including fever and other flu-like symptoms. Other available therapies that have not consistently shown efficacy in placebo-controlled studies include corticosteroids and orgotein. Surgery is considered in patients with Peyronie's disease who have not responded to a trial of conservative medical therapy for 1 year and who are precluded from sexual intercourse. Procedures commonly performed include the Nesbit procedure (or variations of the Nesbit), penile plaque incision/excision with or without grafting, and implantation of a penile prosthesis. Further basic scientific research in Peyronie's disease is likely to identify additional targets for future pharmacotherapy.

Alterations in the Transforming Growth Factor (TGF)-β Pathway as a Potential Factor in the Pathogenesis of Peyronie’s Disease

OBJECTIVES

The development of fibrotic diseases is associated with alterations in the transforming growth factor beta (TGF-beta) pathway. We have investigated the expression and activity of Smad transcription factors of the TGF-beta pathway in primary tunical fibroblasts derived from patients with Peyronie's disease and from controls.

METHODS

Primary fibroblasts were established from biopsies obtained from plaques of 16 patients with Peyronie's disease or the tunica albuginea of 8 control patients. The expression and activity of Smad transcription factors in control and TGF-beta-stimulated primary fibroblasts were investigated at the RNA and protein level by reverse transcription-polymerase chain reaction, Western blotting, and immunofluorescence.

RESULTS

RNA expression levels of Smad3 and Smad4 were significantly increased in fibroblasts from patients with Peyronie's disease. When stimulated with TGF-beta1, fibroblasts showed rapid nuclear translocation of Smad2/3, as soon as 15 min after stimulation. This effect was more pronounced and exhibited an earlier onset in fibroblasts from patients with Peyronie's disease, compared with controls. In addition, an increased nuclear retention time of Smad4 was observed in fibroblasts from patients with Peyronie's disease.

CONCLUSIONS

The expression and activity of Smad transcription factors of the TGF-beta pathway is increased in fibroblasts of patients with Peyronie's disease. Alterations in the TGF-beta pathway seem to be a pathogenetic factor in the development of Peyronie's disease.

Peyronie's disease: etiology, epidemiology and medical treatment

The investigation of medical options for the treatment of Peyronie's disease is lacking controlled clinical trials with uniform standardized assessments and objective measures of deformity, including curvature and circumference. A key to defining the beneficial effects of various medical therapies lies in standardizing the evaluation of the Peyronie's patient across various studies so that the proposed benefits can be confirmed and applied to all populations. Furthermore, basic science research into the pathophysiology of this disorder is likely to yield new insights into potential treatment options and direct future therapies.

Evidence That Osteogenic Progenitor Cells in the Human Tunica Albuginea May Originate from Stem Cells: Implications for Peyronie Disease1

Tissue ossification in Peyronie disease (commonly known as Peyronie's disease [PD]), a localized fibrotic lesion within the tunica albuginea (TA) of the penis, may result from osteogenic differentiation of fibroblasts, myofibroblasts, and/or adult stem cells in the TA, and may be triggered by chronic inflammation, oxidative stress, and profibrotic factors like transforming growth factor beta 1 (TGFB1). In this study, we have investigated whether cultures of cells from normal TA and PD plaques undergo osteogenesis, express markers for stem cells, and originate other cell lineages via processes modulated by TGFB1. We found that TA and PD cells in osteogenic medium (OM) expressed osteogenic markers, alkaline phosphatase, and osteopontin and underwent calcification. PD cells, but not TA cells, formed foci in soft agar that were positive for alkaline phosphatase and calcification and expressed the mRNAs for osteoblast-specific factors pleiotrophin and periostin and bone morphogenic protein 2. Both cultures expressed stem cell marker CD34 antigen but not protein tyrosine phosphatase, receptor type c. TA and PD cells expressed smooth-muscle cell markers smoothelin and transgelin. None of the cultures underwent adipogenesis in adipogenic medium. Incubation with TGFB1 increased osteogenesis and myofibroblast differentiation and reduced CD34 antigen expression in both cultures. TA and PD cells modulated the differentiation of the multipotent C3H 10T(1/2) cells in dual cultures, into osteoblasts and myofibroblasts. In conclusion, both TA and PD cultures contain cells, presumably stem cells, that undergo osteogenic and myofibroblast differentiation, and may induce these processes by paracrine interactions. This may explain progression of fibrosis in the PD plaque and its eventual calcification.

Comparison of gene expression profiles between Peyronie's disease and Dupuytren's contracture

OBJECTIVES

To compare the gene expression alterations in human Peyronie's disease (PD) and Dupuytren's disease (DD) to determine whether they share a common pathophysiology. Multiple mRNA expression profiles of human PD have previously shown that genes that regulate fibroblast replication, myofibroblast differentiation, collagen metabolism, tissue repair, and ossification are involved. DD, a palmar fascia fibrosis, may be associated with PD.

METHODS

Total RNA samples from PD plaques, normal tunica albuginea, Dupuytren's nodules, and normal palmar fascia (nine samples per group) were subjected to differential gene expression profile analysis (Clontech Atlas DNA microarray) comparing PD with tunica albuginea and DD with normal palmar fascia. Changes of more than 2.0 in PD and DD compared with tunica albuginea and normal palmar fascia, respectively, were recorded. Reverse transcriptase-polymerase chain reactions were performed for some genes whose expression was altered in PD.

RESULTS

Some of the gene families upregulated in both PD and DD were (a) collagen degradation: matrix metalloproteinase (MMP), with MMP2 and MMP9, and thymosins (MMP activators), with TMbeta10 and TMbeta4; (b) ossification: osteoblast-specific factors (OSFs) OSF-1 and OSF-2 (DD only); and (c) myofibroblast differentiation: RhoGDP dissociation inhibitor 1. The genes upregulated in PD only were decorin (an inhibitor of transforming growth factor-beta1 and a part of fibroblast replication/collagen synthesis) and early growth response protein. Reverse transcriptase-polymerase chain reaction confirmed these changes.

CONCLUSIONS

These data demonstrate that the pattern of alterations in the expression of certain gene families in PD and DD is similar, suggesting that they share a common pathophysiology and may be amenable to the same therapeutic regimens.

New discoveries in the basic science understanding of Peyronie’s disease

Peyronie's disease is an acquired benign condition representing localized fibrosis of the penis. The disease is caused by microvascular trauma to the penis, with subsequent fibrin deposition resulting in aberrant wound healing and possibly other etiologies. Histopathologic studies of the Peyronie's plaque have demonstrated the role of transforming growth factor-beta 1 in the pathologic development of penile plaque. Animal models have been developed to test pathophysiology and therapeutics. The role of inducible nitric oxide synthase and nitric oxide has been established to limit and counteract fibrosis. Differential gene expression studies have identified candidate up-regulated or down-regulated genes that are involved in the pathophysiology of Peyronie's disease.

L-arginine and phosphodiesterase (PDE) inhibitors counteract fibrosis in the Peyronie's fibrotic plaque and related fibroblast cultures

Inducible nitric oxide synthase (iNOS) is expressed in both the fibrotic plaque of Peyronie's disease (PD) in the human, and in the PD-like plaque elicited by injection of TGFbeta1 into the penile tunica albuginea (TA) of the rat. Long-term inhibition of iNOS activity, presumably by blocking nitric oxide (NO)- and cGMP-mediated effects triggered by iNOS expression, exacerbates tissue fibrosis through an increase in: (a) collagen synthesis, (b) levels of reactive oxygen species (ROS), and (c) the differentiation of fibroblasts into myofibroblasts. We have now investigated whether: (a) phosphodiesterase (PDE) isoforms, that regulate the interplay of cGMP and cAMP pathways, are expressed in both the human and rat TA; and (b) L-arginine, that stimulates NOS activity and hence NO synthesis, and PDE inhibitors, that increase the levels of cGMP and/or cAMP, can inhibit collagen synthesis and induce fibroblast/myofibroblast apoptosis, thus acting as antifibrotic agents. We have found by immunohistochemistry, RT/PCR, and Western blot that PDE5A-3 and PDE4A, B, and D variants are indeed expressed in human and rat normal TA and PD plaque tissue, as well as in their respective fibroblast cultures. As expected, in the PD fibroblast cultures, pentoxifylline (non-specific cAMP-PDE inhibitor) increased cAMP levels without affecting cGMP levels, whereas sildenafil (PDE5A inhibitor) raised cGMP levels. Both agents and L-arginine reduced the expression of collagen I (but not collagen III) and the myofibroblast marker, alpha-smooth muscle actin, as determined by immunocytochemistry and quantitative image analysis. These effects were mimicked by incubation with 8-Br-cGMP, which in addition increased apoptosis, as measured by TUNEL. When L-arginine (2.25 g/kg/day), pentoxifylline (10 mg/kg/day), or sildenafil (10 mg/kg/day) was given individually in the drinking water for 45 days to rats with a PD-like plaque induced by TGF beta1, each treatment resulted in a 80-95% reduction in both plaque size and in the collagen/fibroblast ratio, as determined by Masson trichrome staining. Both sildenafil and pentoxiphylline stimulated fibroblast apoptosis within the TA. Our results support the hypothesis that the increase in NO and/or cGMP/cAMP levels by long-term administration of nitrergic agents or inhibitors of PDE, may be effective in reversing the fibrosis of PD, and more speculatively, other fibrotic conditions.

Wogonin suppresses cellular proliferation and expression of monocyte chemoattractant protein 1 in Peyronie's plaque-derived cells

OBJECTIVE

To test the effect of wogonin on cellular proliferation and expression of monocyte chemoattractant protein 1 (MCP-1) in cells derived from normal and diseased tunica albuginea (TA), as related to Peyronie's disease (PD).

MATERIALS AND METHODS

Cells with characteristics of fibroblasts were isolated from three tissue sources. Those from the plaque of patients with PD were designated as P cells, those from the adjacent, normal-appearing tissue as C cells, and those from the TA of patients without PD as N cells. These cells were treated with wogonin at doses of 0, 10, 20 and 40 micromol/L for 24 h or treated at a fixed dose of 40 micromol/L for 1, 8 and 24 h. Cell proliferation was assayed with a commercial kit, MCP-1 mRNA expression by reverse transcription-polymerase chain reaction, and secreted MCP-1 by enzyme-linked immunosorbent assay.

RESULTS

Wogonin suppressed cell proliferation in a dose-dependent manner; the effect was more pronounced against P cells at 8 and 24 h. Wogonin down-regulated MCP-1 mRNA expression, especially in P cells. Wogonin suppressed the level of secreted MCP-1 by 59-88%. P cells, which secreted far more MCP-1 than N and C cells at 1 h, were suppressed by 88%. C cells were the least suppressed at all three times.

CONCLUSIONS

Wogonin suppressed the proliferation, the expression of MCP-1 mRNA, and the expression of secreted MCP-1 in TA-derived cells. In most cases, the effect of wogonin was greatest against cells derived from the plaque. Wogonin appears to be a worthy candidate for preclinical trials in men with PD.

Peyronie's disease: a review

PURPOSE

We provide a current review of Peyronie's disease.

MATERIALS AND METHODS

We reviewed the world peer reviewed literature on the pathology, pathogenesis, diagnosis and treatment of Peyronie's disease.

RESULTS

The incidence of Peyronie's disease has continuously increased during the last 30 years. However, fewer patients need prosthesis surgery as the sole treatment option because of earlier diagnosis, improved medical therapy, refinement in surgical technique and better understanding of the basic sciences of the disease.

CONCLUSIONS

Currently patients with Peyronie's disease have had improvements in prognosis and experienced an expansion of the available therapeutic options.

Effect of nitric oxide on the differentiation of fibroblasts into myofibroblasts in the Peyronie's fibrotic plaque and in its rat model

The myofibroblast shares phenotypic features of both fibroblasts and smooth muscle cells. It plays a critical role in collagen deposition and wound healing and disappears by apoptosis when the wound is closed. Its abnormal persistence leads to hypertrophic scar formation and other fibrotic conditions. Myofibroblasts are present in the fibrotic plaque of the tunica albuginea (TA) of the penis in men with Peyronie's disease (PD), a localized fibrosis that is accompanied by a spontaneous induction of the inducible nitric oxide synthase (iNOS), also observed in the TGFbeta1-elicited, PD-like lesion in the rat model. iNOS expression counteracts fibrosis, by producing nitric oxide (NO) that reduces collagen deposition in part by neutralization of profibrotic reactive oxygen species. In this study we investigated whether fibroblast differentiation into myofibroblasts is enhanced in the human and rat PD-like plaque and in cultures of human tissue fibroblasts. We also examined whether NO reduces this cell differentiation and collagen synthesis. The myofibroblast content in the fibroblast population was measured by quantitative immunohistochemistry as the ratio between alpha-smooth muscle actin (ASMA; myofibroblast marker) and vimentin (general fibroblast marker) levels. We found that myofibroblast content was considerably increased in the human and TGFbeta1-induced rat plaques as compared to control TA. Inhibition of iNOS activity by chronic administration of L-iminoethyl-L-lysine to rats with TGFbeta1-induced TA lesion increased myofibroblast abundance and collagen I synthesis measured in plaque and TA homogenates from animals injected with a collagen I promoter construct driving the expression of beta-galactosidase. Fibroblast differentiation into myofibroblasts occurred with passage in the cell cultures from the human PD plaque, but was minimal in cultures from the TA. Induction of iNOS in PD and TA cultures with a cytokine cocktail and a NO donor, S-nitroso-N-acetyl penicillamine (SNAP), was detected by immunohistochemistry. Both treatments reduced the total number of cells and the number of ASMA positive cells, whereas only SNAP decreased collagen I immunostaining. These results support the hypotheses that myofibroblasts play a role in the development of the PD plaque and that the antifibrotic effects of NO may be mediated at least in part by the reduction of myofibroblast abundance and lead to a reduction in collagen I synthesis.

Gene expression in Peyronie's disease

Currently, surgical intervention is the only efficacious treatment for Peyronie's disease (PD), a fibromatosis of the tunica albuginea of the penis. Therapies based on the molecular pathways for this disease could provide alternatives to surgical treatment but only recently has the pathophysiology of the Peyronie's disease plaque been investigated at the molecular level. In this review, we examine the current knowledge of gene expression in the PD plaque and the relationship of PD with other fibrotic conditions such as Dupytren's disease. TGFbeta1, along with other growth factors, pro-fibrotic genes, and collagen, are expressed in fibroblasts and myofibroblasts. Myofibroblasts are normally involved in wound contracture and largely eliminated via apoptosis during the late stages of wound remodeling. In the PD plaque, however, these cells persist and may play an important role in the PD plaque fibrosis. The expression levels of TGFbeta1 and pro- and anti-fibrotic gene products, along with the nitric oxide/reactive oxygen species (NO/ROS) ratio in the tunica albuginea, appear to be essential for the formation and progression of the PD plaque and effect the expression of multiple genes. This can be assessed with the recently developed DNA-based chip arrays and results with the PD plaque have been encouraging. OSF-1 (osteoblast recruitment), MCP-1 (macrophage recruitment), procollagenase IV (collagenase degradation), and other fibrotic genes have been identified as being possible candidate regulatory genes. Finally, possible therapeutic avenues for gene-based therapy in the treatment of PD are discussed that may eventually reduce the need for surgical intervention.