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

Kindlin-2 mediates Peyronie's disease through activation of TGF-β/Smad signaling pathway under the presence of TGF-β1

BACKGROUND

Peyronie's disease (PD) causes benign plaques or induration in tunica albuginea (TA). Kindlin-2 regulates the TGF-β1/Smad3 pathway, which accelerates kidney fibrosis. The study is aimed mainly to investigate the impact of Kindlin-2 on PD formation and its signaling pathways, notably the TGF-β/Smad pathway in the presence of TGF-β1.

METHODS

In this mouse investigation, adenovirus TGF-β1 was injected into TA to produce PD. The model was successfully induced 45 days later. Western Blot (WB) and immunohistochemistry (IHC) were utilized to measure Kindlin-2 in PD model tissue. WB and immunofluorescence assays were utilized to confirm the impact of TGF-β1 on Kindlin-2 levels in vitro. The interaction among Kindlin-2, TβRI, and Smad3 was detected using immunoprecipitation (IP) experiments. We examined how TGF-β1 affects Smad3 phosphorylation and downstream gene activation process. Finally, Kindlin-2 and the level of tissue fibrosis were examined in PD model.

RESULTS

Kindlin-2 levels were elevated in the TGF-β1-induced PD model, confirming that TGF-β1 can increase Kindlin-2 levels in primary PD cells. Moreover, Kindlin-2 mediates Smad3-TβRI interaction, activates p-Smad3, and enhances TGF-β1 target gene expression. In vivo investigations reveal that Kindlin-2 promotes PD development and tissue fibrosis. The regulatory effects of Kindlin-2 need the presence of TGF-β1. Tissue fibrosis can be reduced by downregulating Kindlin-2.

CONCLUSION

Kindlin-2 does not directly activate Smad3 to induce tissue fibrosis. Instead, it exerts its effect through the combined influence of TGF-β1. Inhibiting Kindlin-2 could potentially be a treatment for PD.

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.

MicroRNA-29b attenuates fibrosis in a rat model of Peyronie's disease

BACKGROUND

Peyronie's disease is characterized by the formation of fibrotic plaques in the penile tunica albuginea. Effective treatments are limited, warranting the investigation of new promising therapies, such as the application of microRNAs that regulate fibrosis-related genes.

OBJECTIVE

We aimed to investigate the therapeutic potential of mimicking microRNA-29b in a fibrin-induced rat model of Peyronie's disease.

MATERIAL/METHODS

The study was designed in two phases. To establish an optimal Peyronie's disease model, rats received either human fibrin and thrombin or saline solutions into the tunica albuginea on days 0 and 5. The animal model validation was done through expression and histopathological analyses, the latest by an experienced uropathologist. After validation, we performed microRNA-29b treatment on days 14, 21, and 28 of the study. This phase had control (normal saline) and scramble (microRNA scramble) groups. The mid-penile shaft was removed on day 30 for histological examination and molecular analyses in both study stages.

RESULTS

The control group displayed typical tunica albuginea histologic architecture in the animal model validation. In Peyronie's disease group, the Hematoxylin and eosin and Masson Trichrome staining methods demonstrated an interstitial inflammatory process with concomitant dense fibrotic plaques as well as disarrangement of collagen fibers. Additionally, we found out that reduced microRNA-29b (p = 0.05) was associated with significantly increased COL1A1 and transforming growth factor β1 genes and proteins (p > 0.05) in the Peyronie's disease group. After treatment with mimic microRNA-29b stimulation, the Hematoxylin & eosin and Masson Trichrome staining revealed a discrete and less dense fibrotic plaque. This result was associated with significantly decreasing expression of COL1A1, COL3A1, and transforming growth factor β1 genes and proteins (p < 0.05).

DISCUSSION

The fibrin-induced animal model showed significant histopathological and molecular changes compared to the Control group, suggesting that our model was appropriate. Previous findings have shown that increased expression of microRNA-29b was associated with decreased pathological fibrosis. In the present study, treatment with microRNA-29b decreased the gene and protein expression of collagens and transforming growth factor β1. This study reveals the therapeutic potential for Peyronie's disease involving molecular targets.

CONCLUSION

MicroRNA-29b application on the rat's tunica albuginea attenuated fibrosis, arising as a novel potential strategy for Peyronie's disease management.

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.

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.

Pharmacotherapy in Peyronie's disease: a state-of-the-art review on established contemporary and emerging drugs

INTRODUCTION

Current clinical guidelines on Peyronie's disease (PD) advocate non-surgical treatment options as the first-line therapy despite inconsistent clinical outcomes when compared to definitive penile reconstructive surgery.

AREAS COVERED

This article examines the current understanding of established contemporary and emerging pharmacotherapies for PD. Emphasis has been placed on published clinical studies on drugs in the last 10 years.

EXPERT OPINION

Published studies have shown that combination therapy is likely more effective than monotherapy. Combined treatment modalities involving various oral and/or intralesional pharmacotherapies together with mechanical devices or clinical psychosexual therapy may provide additional or synergistic benefits for PD patients. A multidisciplinary approach coupled with more novel targets for pharmacological intervention could deliver a more effective treatment paradigm to prevent or at least delay the need for definitive penile reconstructive surgery. Drugs targeting the inhibition of TGF-β1 pathway and myofibroblast transformation are of great interest and studies into next-generation genetic sequencing and transcriptional biomarker regulatory pathways in PD will provide useful insights into the pathophysiology of PD, and assist the development of future regenerative technology including cellular-based therapies to target various anti-fibrotic molecular mechanisms and the potential to be integrated into existing treatment armamentarium for PD.

Urologists' knowledge base and practice patterns in Peyronie's disease. A national survey of members of the italian andrology society

Peyronie's disease is a chronic inflammatory disease involving the formation of plaque in the tunica albuginea of the corpora cavernosa, resulting in penis deformity. It is often associated with penile pain, especially in younger patients, but it is not rare for pain to be absent; the disease is also associated with erectile dysfunction and a depressive state in a large percentage of cases.

OBJECTIVE

Aim of our study was to explore the basic knowledge base and diagnostic and therapeutic practice patterns in Peyronie's disease (PD) of a large number of physicians belonging to the Italian Andrology Society (SIA).

METHODS

Our survey is based on two questionnaires which were e-mailed to the members of the SIA. The first questionnaire explored diagnostic and therapeutic practice patterns of SIA physicians, while the second questionnaire focused on their knowledge of the disease, as well as their training and level of experience in the specific field. We then planned to compare our outcomes with similar PD surveys from other countries.

RESULTS

The first questionnaire was answered by 142 SIA physicians. The second questionnaire was answered by 83 SIA physicians. Most respondents (74.6%) chose penile ultrasonography as first-line diagnostic approach and 47.1% prefer to perform a color Doppler ultrasound after pharmaco-induced erection. Concerning the therapeutic practice patterns in active stage of the disease, most respondents (99.29%) prefer conservative medical therapy. Additionally, most respondents (64.78%), when failure of conservative treatment had been established, considered surgical treatment necessary, specifically corporoplasty, which may be associated with other techniques.

CONCLUSIONS

The results of our survey show that, in comparison to their foreign counterparts, Italian SIA uro-andrologists have a more proactive diagnostic approach right from when patients first present. When PD is still in its active stage, SIA uro-andrologists mostly opt for medical therapy. In advanced disease or if conservative treatment fails, our survey indicates a greater preference for surgical treatment. Answers to the theoretical knowledge questions showed that SIA physicians have a good understanding of the disease's etiology, epidemiology, and clinical picture, and of the appropriate indications for treatment.

Evaluation of Long-Term Clinical Outcomes and Patient Satisfaction Rate Following Low Intensity Shock Wave Therapy in Men With Erectile Dysfunction: A Minimum 5-Year Follow-Up on a Prospective Open-Label Single-Arm Clinical Study

Introduction

Low intensity extracorporeal shock wave therapy (LIESWT) improves erectile function (EF) in men with vascular erectile dysfunction (ED) but longer-term outcomes remain unknown.

Aim

To evaluate the clinical outcomes of LIESWT at a minimum 5-year follow-up.

Methods

This is an open-label single-arm prospective study involved men with vascular ED who received LIESWT.

Main Outcome Measure

Changes in patient demographics, IIEF-5 and Erectile Dysfunction Inventory of Treatment Satisfaction (EDITS) scores, as well as overall satisfaction score (on a 5-point scale) were reviewed at 12, 24, 48, and 60 months after completion of LIESWT. A chi-square contingency analysis was used to examine the relationship between erectile function score and treatment satisfaction, with statistical significance set at 5%.

Results

The mean follow-up period was 69.9 (63–82; median 76) months. The mean IIEF-5 scores for pretreatment and after treatment at 12, 24, 48, and 60 months were 14.8, 17.6, 16.8, 16.5, and 16.5 while the percentages of patients who reported an improvement in IIEF-5 score by 5 points were 60%, 45%, 40%, and 40%; and EDITS scores >50% were recorded in 70%, 55%, 50%, and 48% of patients at 12, 24, 48, and 60 months post-LIESWT. Ten patients required medical therapy and 2 patients opted for penile prosthesis implantation. The overall satisfaction rate appeared sustained subsequent follow-up (score 4 out of 5; 68% vs 50% vs 40% vs 40% at 12, 24, 48, and 60 months). There were minor time-limited, but no significant adverse event reported.

Conclusion

This long-term study showed the observed clinical improvement in EF continues to deteriorate but appears to plateau at 40% clinical efficacy at 48–60 months after completion of LIESWT. The absence of penile pain and deformity at 5-year follow-up supports the long-term safety data of LIESWT in men with ED.

Chung E, Cartmill R. Evaluation of Long-Term Clinical Outcomes and Patient Satisfaction Rate Following Low Intensity Shock Wave Therapy in Men With Erectile Dysfunction: A Minimum 5-Year Follow-Up on a Prospective Open-Label Single-Arm Clinical Study. Sex Med 2021;9:100384.

Molecular Mechanisms and Current Pharmacotherapy of Peyronie's Disease: A Review

Peyronie’s disease (PD) is a localized fibrotic lesion of the penis that has adverse effects on men’s health. In this review, we summarized the molecular mechanisms and pharmacotherapies of PD. A literature search was conducted using PubMed and Cochrane Library during 2001–2020. Although no oral or topical medication demonstrated efficacy in monotherapy of PD, several intralesional medications have yielded promising results. Currently, the effective strategy in management of PD should be combined modality therapy, including but not limited to pharmacotherapy, mechanical therapy, and psychotherapy. Meanwhile, basic research is still necessary to facilitate the development of novel and more reliable treatments. In future, more attention should be given simultaneously to epigenetic changes, inflammatory cytokines, the abnormal wound-healing process, and profibrotic and anti-fibrotic factors to provide more options for this refractory disease.

A state-of-art review on collagenase Clostridium Histolyticum and Peyronie's disease: drug profile, clinical evidence and safety outcomes

Introduction: Collagenase clostridium histolyticum (CCH) is the first and only licensed medical treatment for men with Peyronie's disease (PD). Published literature shows intralesional CCH injection as an effective and safe minimally invasive treatment in a specific subgroup of PD patients.Areas covered: The authors discuss pharmacodynamics and pharmacokinetics as well as clinical outcomes and safety profile from major CCH studies in PD. All relevant CCH studies published in PubMed and EMBASE databases up to June 2019 were included.Expert opinion: Given the variability in treatment schedule and drug access coupled with the potential need for further treatment, strict patient selection and the use of adjunctive strategies are key determinants to maximize clinical efficacy of intralesional CCH. Furthermore, longer-term follow-up data on the clinical outcomes, safety and durability of CCH in larger multi-center studies and post-marketing surveillance data are necessary to provide a comparison to other standard PD treatment options.

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.

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.

Extracellular matrix alterations after blood instillation in tunica albuginea of rats

The cause of Peyronie's disease (PD) is still not completely understood. The objective of this study, therefore, was to analyze the histological and biochemical alterations that occur after the instillation of blood in the tunica albuginea (TA) of rats with an emphasis on the remodeling process of ECM. Thirty male Wistar rats were divided into 4 groups: two control groups with instillation of distilled water in TA followed by penectomy after 15 days or 45 days, respectively and two experimental groups with instillation of blood in TA followed by penectomy after 15 days or 45 days, respectively. Histological, immunofluorescent and immunohistochemical analyses were performed. The higher presence of fibrotic tissue in rats injected with blood demonstrated alterations in TA similar to inflammation found in PD. The increased expression of TGF-β, MMP9, HPSE, and biglycan associated with the decreased expression of syndecan-1 and aggrecan in the experimental groups suggested an enhancement in the remodeling of ECM. The results contribute to show that blood instillation on TA appears to trigger alterations in the ECM similar to the ones found in inflammatory diseases such as 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 Cells in Male Sexual Dysfunction: Are We Getting Somewhere?

INTRODUCTION

Stem cells for sexual disorders are steadily being introduced into clinical trials. Two conditions of importance are the main target for this line of treatment, especially when regarding the wide array of translational and basic science highlighting the potential advantages of regenerative therapy: erectile dysfunction (ED) and more recently Peyronie disease (PD). Cellular therapy offers a treatment modality that might reverse disease progression. It would be used in a curative setting, in contrast to other pharmaceutical agents that are currently available.

AIM

To review basic preclinical studies and recent clinical trials of stem cells on ED and PD.

METHODS

A search of the medical literature for the following terms was performed using PubMed: stem cells, cellular therapy, erectile dysfunction, Peyronie's disease, and clinical trial.

MAIN OUTCOME MEASURES

A non-systematic narrative review and critical reflection on preclinical and clinical studies administering stem cells for ED and PD in animal models and human subjects.

RESULTS

Numerous studies have confirmed the beneficial functional effects of stem cell injection in established animal models on ED and PD. Various stem cell types have been adopted, from embryonic to adult mesenchymal cell types. Each cell type offers distinctive advantages and disadvantages. Diverse administrations of stem cells were investigated, with insignificant variability in the ultimate results. Stem cells appear to have a pronounced paracrine effect, rather than the classic engraftment and differentiation hypothesis. Phase 1 clinical trials using stem cells have not reported any severe adverse events in animals. However, these results cannot be extrapolated to draw any conclusions about efficacy in human patients.

CONCLUSION

Stem cells have an established efficacy in preclinical studies and early clinical trials. Studies are currently being published demonstrating the safety of intrapenile injection of autologous bone marrow- and adipose tissue-derived stem cells. Soebadi MA, Milenkovic U, Weyne E, et al. Stem Cells in Male Sexual Dysfunction: Are We Getting Somewhere? Sex Med Rev 2017;5:222-235.

Peyronie's disease: a literature review on epidemiology, genetics, pathophysiology, diagnosis and work-up

Peyronie's disease (PD), a fibromatous disorder of the tunica albuginea of the penile corpus cavernosum, named after the French physician Francois de la Peyronie, is characterized by pain, plaque formation, penile curvature, and plaque calcification. The epidemiological data on PD is inconsistent, with recent reports stating a prevalence of up to 9%, and the condition affecting men of all ages, from teenagers to septuagenarians. We are just beginning to elucidate the role of genetics as a causative factor for PD. Chromosomal abnormalities and single-nucleotide polymorphisms have been shown to be associated with fibrotic diatheses. Tunical mechanical stress and microvascular trauma are major contributory factors to the pathophysiology of PD. The diagnosis of PD can be made using a combination of clinical history, physical examination and, sometimes, imaging modalities. A better understanding of the molecular pathophysiology of this condition remains paramount for the development of newer and more effective disease-targeted interventions.

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.

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.

Penile traction therapy and Peyronie's disease: a state of art review of the current literature

In recent years, penile traction therapy (PTT) has gained considerable interest as a novel nonsurgical treatment option for men with Peyronie's disease (PD) and short penises. The current published literature suggests that selected cases of PD may benefit from a conservative approach with PTT, resulting in increased penile length and reduction of penile deformity. It appears to be safe and well tolerated but requires a great deal of patient compliance and determination. This article reviews the current literature pertaining to the use of PTT in men with PD, short penises and in the setting of pre- and postprosthesis corporal fibrosis.

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.