Treatment of Peyronie's disease with PDE5 inhibitors: an antifibrotic strategy

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.

A novel technique for unilateral dissection of the penile neurovascular bundle to prevent loss of penile sensation during treatment of Peyronie's disease-Initial results of a pilot study

Background

Plaque incision/excision and grafting are surgical techniques used to treat patients with Peyronie's disease who are refractory to less invasive interventions, have severe penile curvature, or have an hourglass deformity. However, the procedure carries the risk of penile sensory loss because of the need for dissection of the neurovascular bundle (NVB). The aim of this study was to assess the feasibility of a novel technique for unilateral NVB dissection and its ability to preserve penile sensitivity while maintaining adequate correction of the penile curvature.

Materials and methods

Charts of patients who underwent unilateral NVB dissection during Peyronie's plaque incision/excision and grafting were retrospectively reviewed. All patients received preprocedural intracavernosal injections of TriMix, and the curvature was measured to be >70 degrees. In 3 cases, an incision and minimal excision of the plaque were performed at the point of maximum curvature on the concave side of the curvature. In 3 cases, Tutoplast allografts (Coloplast US, Minneapolis, MN) were used, whereas autografts were used in 2 other cases. All patients were examined at 1, 3, and 6 months after the procedure when curvature and penile sensation were assessed.

Results

Five patients underwent this procedure. The mean age of patients was 55 years (45-70 years). All plaques were dorsally located. The mean preoperative curvature was 78 degrees (75-90 degrees). At the 6-month follow-up, all patients had <15 degrees residual curvature and were satisfied with their cosmetic results. Only 1 patient continued with phosphodiesterase-5 inhibitors to improve potency at the 6-month follow-up. All patients reported normal penile glans sensation. Four patients experienced decreased sensation at the site of NVB dissection, but this was only detected when compared with the contralateral side. Only 2 patients reported a difference after 6 months, and only a minor area of involvement was noted.

Conclusions

Unilateral NVB dissection is a feasible technique that does not compromise surgical success in curvature correction and helps avoid sensory injury to the penile glans.

Advancements in Phosphodiesterase 5 Inhibitors: Unveiling Present and Future Perspectives

Phosphodiesterase 5 (PDE5) inhibitors presented themselves as important players in the nitric oxide/cGMP pathway, thus exerting a profound impact on various physiological and pathological processes. Beyond their well-known efficacy in treating male erectile dysfunction (ED) and pulmonary arterial hypertension (PAH), a plethora of studies have unveiled their significance in the treatment of a myriad of other diseases, including cognitive functions, heart failure, multiple drug resistance in cancer therapy, immune diseases, systemic sclerosis and others. This comprehensive review aims to provide an updated assessment of the crucial role played by PDE5 inhibitors (PDE5-Is) as disease-modifying agents taking their limiting side effects into consideration. From a medicinal chemistry and drug discovery perspective, the published PDE5-Is over the last 10 years and their binding characteristics are systemically discussed, and advancement in properties is exposed. A persistent challenge encountered with these agents lies in their limited isozyme selectivity; considering this obstacle, this review also highlights the breakthrough development of the recently reported PDE5 allosteric inhibitors, which exhibit an unparalleled level of selectivity that was rarely achievable by competitive inhibitors. The implications and potential impact of these novel allosteric inhibitors are meticulously explored. Additionally, the concept of multi-targeted ligands is critically evaluated in relation to PDE5-Is by inspecting the broader spectrum of their molecular interactions and effects. The objective of this review is to provide insight into the design of potent, selective PDE5-Is and an overview of their biological function, limitations, challenges, therapeutic potentials, undergoing clinical trials, future prospects and emerging uses, thus guiding upcoming endeavors in both academia and industry within this domain.

Pharmacotherapies in Dupuytren Disease: Current and Novel Strategies

Dupuytren disease is a benign, progressive fibroproliferative disorder of the hands. To date, only one pharmacotherapy (clostridial collagenase) has been approved for use in Dupuytren disease. There is a great need for additional nonsurgical methods that can be used to either avoid the risks of invasive treatments or help minimize recurrence rates following treatment. A number of nonsurgical modalities have been discussed in the past and continue to appear in discussions among hand surgeons, despite highly variable and often poor or no long-term clinical data. This article reviews many of the pharmacotherapies discussed in the treatment of Dupuytren disease and novel therapies used in inflammation and fibrosis that offer potential treatment options.

Fibrotic Diseases of the Human Urinary and Genital Tract: Current Understanding and Potential Strategies for Treatment

Fibrosis is a disease condition characterized by abnormalities of the extracellular matrix, such as accumulation of the transforming growth factor β, infiltration by myofibroblasts, deposition of collagen, and a generalized dysregulation of collagen maturation. It can severely impair the function of organs by replacing normal tissue with a highly collagenized matrix, thereby reducing the elasticity and compliance of tissues. Fibrotic diseases of the genitourinary tract present relevant problems in healthcare, and their principles of pathophysiology remain unclarified; hence, the armamentarium for prevention and treatment is limited. These diseases include renal fibrosis, Peyronie's disease and ureteral and urethral strictures due to perturbations in the process of wound healing in response to injuries. Such deteriorations may contribute to obstructive uropathies or sexual dysfunction. This review provides a brief overview of the most frequent fibrotic diseases of the genitourinary system and of how the pathophysiology is related to symptoms, and also highlights potential therapeutic strategies to address the abnormal deposition of collagen. Although the understanding of factors associated with fibrotic conditions of the urinary and genital tract is still limited, some beneficial advances have been made. Further research will serve to provide a more comprehensive insight into factors responsible for the development of fibrotic tissue deposition.

The Italian Society of Andrology and Sexual Medicine (SIAMS), along with ten other Italian Scientific Societies, guidelines on the diagnosis and management of erectile dysfunction

PURPOSE

Erectile dysfunction (ED) is one of the most prevalent male sexual dysfunctions. ED has been in the past mistakenly considered a purely psycho-sexological symptom by patients and doctors. However, an ever-growing body of evidence supporting the role of several organic factors in the pathophysiological mechanisms underlying ED has been recognized.

METHODS

The Italian Society of Andrology and Sexual Medicine (SIAMS) commissioned an expert task force involving several other National Societies to provide an updated guideline on the diagnosis and management of ED. Derived recommendations were based on the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) system.

RESULTS

Several evidence-based statements were released providing the necessary up-to-date guidance in the context of ED with organic and psychosexual comorbidities. Many of them were related to incorrect lifestyle habits suggesting how to associate pharmacotherapies and counseling, in a couple-centered approach. Having the oral therapy with phosphodiesterase type 5 inhibitors as the gold standard along with several other medical and surgical therapies, new therapeutic or controversial options were also discussed.

CONCLUSIONS

These are the first guidelines based on a multidisciplinary approach that involves the most important Societies related to the field of sexual medicine. This fruitful discussion allowed for a general agreement on several recommendations and suggestions to be reached, which can support all stakeholders in improving couple sexual satisfaction and overall general health.

Sildenafil, a Type-5 Phosphodiesterase Inhibitor, Fails to Reverse Myeloid-Derived Suppressor Cell-Mediated T Cell Suppression in Cells Isolated From Tuberculosis Patients

Successful TB treatment is hampered by increasing resistance to the two most effective first-line anti-TB drugs, namely isoniazid and rifampicin, thus innovative therapies focused on host processes, termed host-directed therapies (HDTs), are promising novel approaches for increasing treatment efficacy without inducing drug resistance. We assessed the ability of Sildenafil, a type-5 phosphodiesterase inhibitor, as a repurposed compound, to serve as HDT target, by counteracting the suppressive effects of myeloid-derived suppressor cells (MDSC) obtained from active TB cases on T-cell responsiveness. We confirm that MDSC suppress non-specific T-cell activation. We also show that Sildenafil treatment fails to reverse the MDSC-mediated suppression of T-cell functions measured here, namely activation and proliferation. The impact of Sildenafil treatment on improved immunity, using the concentration tested here, is likely to be minimal, but further identification and development of MDSC-targeting TB host-directed therapies are warranted.

[French Urological Association (AFU) guidelines for Peyronie's disease assessment and treatment]

INTRODUCTION

Peyronie's disease is a common cause for consultation in urology. Many controversies surround its treatment. No French Guidelines have been published so far. The Committee of Andrology and Sexual Medicine of the French Association of Urology therefore offers a series of evidence-based recommendations.

MATERIALS AND METHODS

These recommendations are made according to the ADAPTE method, based on European (EAU, ESSM), American (AUA, ISSM) and Canadian (CAU) recommendations, integrating French specificities due to the availability of treatments, and an update of the recent bibliography.

RESULTS

The assessment of the disease is clinical. Patients with functional impairment or significant psychological repercussions may be offered treatment. The benefits and drawbacks of each treatment should be explained to the patient. Regarding non-surgical treatments, no available treatment has market authorization in France. Vitamin E is not recommended. Analgesic (oral or low-intensity shock waves) or proerectile treatments may be offered as needed, as well as traction therapy. Due to the unavailability of collagenase injections, verapamil injections may be offered. Surgical treatments are to be considered in the stabilized phase of the disease, and consist of performing a plication, an incision-graft or the placement of a penile implant according to the patient's wishes, the curvature and the penis size, as well as erectile function. Combination treatments can be offered.

CONCLUSION

The management of Peyronie's disease is complex, and the levels of evidence for treatments are generally low. The success of treatment will depend on the quality of the initial assessment, the patient's information and understanding of the expected effects, and the practitioner's experience.

Peyronie's disease: pharmacological treatments and limitations

Introduction: Peyronie's disease (PD) is a disorder of the tunica albuginea from disordered and excessive deposition of collagen resulting in a palpable scar, pain, erect penile deformity and erectile dysfunction that significantly impacts patients both physically and emotionally.Areas Covered: Several treatment options have been described for PD, including shockwave therapy, traction therapy, both oral and intralesional pharmacological options, and surgery. This review seeks to examine the data for different types of non-surgical treatments for PD. We review how various treatment modalities impact several relevant clinical endpoints for Peyronie's disease, including effects on pain, penile curvature, plaque formation, and erectile function. We performed a literature search using PubMed and SCOPUS while referencing AUA, EAU, and CUA guidelines for management of Peyronie's Disease for studies published 1980-2020.Expert opinion: Intralesional collagenase injections have the strongest evidence and are the only FDA approved intralesional treatment for PD. Penile traction therapy (PTT) is low risk and may be beneficial in patients willing to invest significant time using the devices. Furthermore, oral combination therapy with other modalities may provide some benefit. Further investigation is required to better understand pathophysiology of PD and clarify the therapeutic utility of existing treatments, potentially with a multimodal strategy.

Medical, non-invasive, and minimally invasive treatment for Peyronie's disease: A systematic review

BACKGROUND

The treatment of Peyronie's disease (PD) remains a dilemma as the true pathogenesis of PD remains an enigma. Consequently, new molecules and therapies continue to evolve. The safety and efficacy of conservative treatment for PD have not yet established.

OBJECTIVES

To provide the available information of the status of conservative therapy for PD.

METHODS

A systematic literature search was conducted using PubMed, EMBASE, and the Cochrane Library for English-language journal articles between January 2000 and July 2019, using the terms "Conservative treatment for PD", "medical treatment for PD", "non-invasive therapies for PD" and "minimally invasive therapies for PD". This systematic review was conducted in agreement with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) system. We also manually reviewed references from selected articles. The risk of bias in the included RCTs was assessed using the Cochrane Risk of Bias Assessment tool (RoB 2).

RESULTS

Conservative treatment is accepted as the initial treatment step in most of the cases. This kind of therapy includes various methods of treatment such as medical, non-invasive, and minimally invasive therapies. Ideal management of PD is not yet available. It is not possible to assess the value of treatment without well-designed, randomized, placebo-controlled, large-scale clinical studies.

CONCLUSION

Optimistically, in the near future, we may witness emergence of efficacious new agents and modalities to revolutionize medical, non-invasive, and minimally invasive treatment of this devastating condition.

Peyronie's disease: new paradigm for the treatment of a unique cause of erectile dysfunction

Peyronie's Disease is an incurable condition of the tunica albuginea of the penis associated with scarring, plaque formation, and penile deformity on erection. It is often associated with erectile dysfunction. Recent data have supported a familial and genetic predisposition to this chronic condition. The etiology of Peyronie's Disease is unknown, but is likely associated with multiple micro traumas to the erect penis in men who are susceptible to the scarring typical of Peyronie's Disease. The treatment of Peyronie's Disease has improved over the past decade as a result of animal studies and the approval of new medications. In the acute phase of the condition, phosphodiesterase type 5 inhibitors have been shown to have some benefit and are supported by animal studies demonstrating reduced fibrosis of the penis in animal models of Peyronie's Disease. In the stable phase of the disease, newer injectable agents have shown great promise. Collagenase clostridium histolyticum is approved for the treatment of Peyronie's plaques by direct injection into the scarred tissue with data showing satisfactory safety and efficacy. Surgical procedures for penile straightening have been refined with improved outcomes in the past decade. For those men with erectile dysfunction and Peyronie's Disease, penile implants can restore erectile function and form. As a result of the new understanding of the risk factors for Peyronie's Disease and recent advances in treatment options, the algorithm for the treatment of Peyronie's Disease has improved outcomes for patients and their partners.

Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie's Disease

BACKGROUND

Myofibroblast transformation is a key step in the pathogenesis of Peyronie's disease (PD). Phosphodiesterase type 5 inhibitors (PDE5is) and selective estrogen receptor modulators (SERMs) can prevent the formation of fibrosis in in vitro and in vivo models of PD. However, it is unknown whether these drugs can also reverse established fibrosis.

AIM

To investigate whether PDE5is and SERMs can reverse transforming growth factor beta 1 (TGF-β1)-induced myofibroblast transformation and determine the point of no return.

METHODS

In-Cell enzyme-linked immunosorbent assay was used to quantify TGF-β1-induced myofibroblast transformation of human primary fibroblasts isolated from tunica albuginea (TA) of patients undergoing surgery for treatment of PD. Extracellular matrix production and collagen contraction assays were used as secondary assays. Reverse transcription-quantitative polymerase chain reaction and In-Cell enzyme-linked immunosorbent assay were used to measure drug target expression. PDE5i (vardenafil) and SERM (tamoxifen) were applied at various time points after TGF-β1.

OUTCOMES

Reversibility of myofibroblast transformation and drug target expression were investigated in a time-dependent manner in TA-derived fibroblasts.

RESULTS

Vardenafil or tamoxifen could not reverse the myofibroblast traits of alpha-smooth muscle actin expression and extracellular matrix production, whereas only tamoxifen affected collagen contraction after 72 hours of TGF-β1 treatment. Phosphodiesterase 5A and estrogen receptor (ER)-β were downregulated after 72 hours, and estrogen receptor -α protein could not be quantified. Tamoxifen could prevent myofibroblast transformation until 36 hours after TGF-β1 treatment, whereas vardenafil could prevent only 24 hours after TGF-β1 treatment. This was mirrored by downregulation of drug targets on mRNA and protein level. Furthermore, antifibrotic signaling pathways, peroxisome proliferator-activated receptor gamma and betaglycan (TGFB receptor III), were significantly downregulated after 36 hours of TGF-β1 exposure, as opposed to upregulation of profibrotic thrombospondin-1 at the same time point.

CLINICAL TRANSLATION

This study suggests that using PDE5is and SERMs might only help for early-phase PD and further highlights the need to test drugs at the appropriate stage of the disease based on their mechanism of action.

STRENGTHS & LIMITATIONS

The study uses primary human TA-derived fibroblasts that enhances translatability of the results. Limitations include that only 1 example of PDE5i- and SERM-type drug was tested. Time course experiments were only performed for marker expression experiments and not for functional assays.

CONCLUSION

This is the first study to demonstrate that timing for administration of drugs affecting myofibroblast transformation appears to be vital in in vitro models of PD, where 36 hours of TGF-β1 treatment can be suggested as a "point of no return" for myofibroblast transformation. Ilg MM, Stafford SJ, Mateus M, et al. Phosphodiesterase Type 5 Inhibitors and Selective Estrogen Receptor Modulators Can Prevent But Not Reverse Myofibroblast Transformation in Peyronie's Disease. J Sex Med 2020;17:1848-1864.

[Non-surgical management of Peyronie's disease: State of current knowledge]

BACKGROUND

Peyronie's disease is an inflammatory disorder of the penis, where scar tissue creates a plaque at the level of the albuginea, limits its extension, and leads to a bent and shorter penis during erections. There are no international standards for the evaluation and the treatment of the disease. The aim of this article is to review the current knowledge about the management of Peyronie's disease and to suggest an algorithm to help physicians evaluate and manage this condition.

MATERIAL AND METHODS

A literature review was conducted through PubMed database following PRISMA guidelines using the Mesh terms: Peyronie, disease, treatment and diagnosis. Results are presented in a descriptive manner.

RESULTS

Multiple treatment strategies have been proposed, but no conclusive randomized clinical trial is done to assess their efficacies. The oral treatment was shown to be more beneficial in the setting of a multi-modal approach to treat the acute phase. The non-steroidal anti-inflammatories and the potassium para-aminobenzoate are superior to the other molecules of oral therapy for pain management. Local treatment with topical verapamil, iontophoresis and intra-lesional injection of verapamil, interferon alfa-2b and collagenase clostridium histolyticum (CCH) revolutionized the management of the disease by the modification of the plaque size and angulation. Alternative treatments using extra-corporeal shock wave or traction devices are promising. Intra-lesional injection of CCH is the only therapy approved by the Food and Drug Administration for this condition after the stabilization of the disease. The channeling of the plaque before CCH injections is making better results than the initial protocol, concerning angulation improvement.

CONCLUSION

Multiple therapeutic strategies exist for the management of the Peyronie's disease, but they lack evidence based data. Further randomized clinical trials are needed to evaluate the current practices and to study more efficient treatments.

Evaluating collagenase Clostridium histolyticum administration protocols in the treatment of Peyronie's disease

PURPOSE OF REVIEW

Treatment of Peyronie's disease with collagenase Clostridium histolyticum (CCh) has gained world-wide adoption following the phase III clinical trials IMPRESS I and II. However, the optimal treatment parameters remain largely unknown. Many groups have made modifications to CCh treatment in Peyronie's disease in recent years. This review aims to discuss the variations in CCh treatment reported and associated outcomes.

RECENT FINDINGS

Variations in CCh treatment protocols include administering higher CCh doses (0.9 mg) less frequently (q1month), use of home penile modeling, use of angulating penile traction devices, and vacuum therapy devices. Authors have reported different injection techniques to include three-point fans and tunneling techniques. Patient selection has expanded to include and evaluate responses among men with some extent of plaque calcification, and ventral curves.

SUMMARY

Since publication of the IMPRESS trials, several variations of CCh treatment have been reported with similar treatment responses to the original trials. However, future studies are required with prospective, randomized comparative designs to identify the optimal treatment strategies for men with Peyronie's disease.

Myeloid-Derived Suppressor Cells as Target of Phosphodiesterase-5 Inhibitors in Host-Directed Therapeutics for Tuberculosis

Resistance toward current and new classes of anti-tuberculosis (anti-TB) antibiotics are rapidly emerging; thus, innovative therapies focused on host processes, termed host-directed therapies (HDTs), are promising novel approaches for shortening therapy regimens without inducing drug resistance. Development of new TB drugs is lengthy and expensive, and success is not guaranteed; thus, alternatives are needed. Repurposed drugs have already passed Food and Drug Administration (FDA) as well as European Medicines Agency (EMA) safety requirements and may only need to prove efficacy against Mycobacterium tuberculosis (M.tb). Phosphodiesterases (PDEs) hydrolyze the catalytic breakdown of both cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) to their inactive mononucleotides. Advances in molecular pharmacology have identified 11 PDE families; and the success of sildenafil, a PDE-5 selective inhibitor (PDE-5i), in treating pulmonary hypertension and erectile dysfunction has invigorated research into the therapeutic potential of selective PDE inhibitors in other conditions. Myeloid-derived suppressor cells (MDSCs) suppress anti-TB T-cell responses, likely contributing to TB disease progression. PDE-5i increases cGMP within MDSC resulting in the downregulation of arginase-1 (ARG1) and nitric oxide synthase 2 (NOS2), reducing MDSC's suppressive potential. The effect of this reduction decreases MDSC-induced T-cell-suppressive mechanisms. This review highlights the possibility of HDT targeting of MDSC, using a PDE-5i in combination with the current TB regimen, resulting in improved TB treatment efficacy.

Minimally invasive therapies for Peyronie's disease: the current state of the art

Peyronie's disease (PD) is a relatively common condition that can result in significant penile deformity, sexual dysfunction, and psychological bother. Surgical straightening offers the highest probability of success during the stable phase of the disease. However, for men in the acute phase of PD or for those with less severe deformity who elect to avoid surgery, a variety of non-surgical treatment options are available. Oral therapies, including L-citrulline and pentoxifylline, are most useful as part of a combination regimen rather than as monotherapy. Intralesional therapy with IFN-α2b, verapamil, and collagenase clostridium histolyticum (CCH) can cause significant reduction in penile curvature, yet these results may not be clinically significant for men with more severe curvature. Further investigation into the timing of administration and optimal patient characteristics is required. Penile traction therapy offers a clinically significant improvement in penile length and curvature. However, this has traditionally required hours of daily therapy. Overall, a combination of oral, topical, injection and traction therapies may provide the most significant benefit among the non-surgical modalities for PD.

Effect of Intracorporeal Human Adipose-Derived Stem Cells (hADSCs) on Corpora Cavernosa Transforming Growth Factor β1 (TGFβ1) and Collagen Type I Concentration in Wistar Rat Priapism Model

Introduction

The ischemic process in priapism can lead to displacement of normal tissue with fibrotic tissue, due to collagen deposition, and eventually leads to erectile dysfunction. Many studies have identified that the supernatant of adipose tissue–derived stem cells (ADSCs) significantly ameliorates fibrosis of different tissue, but limited attention has been paid to its efficacy on fibrosis of the corpora cavernosa.

Methods

A total of 22 Wistar rats divided into five groups, with two groups each consisting of five male wistar rats with priapism without human ADSC (hADSC) therapy (group I) and two other groups consisting of five rats with priapism, were given 10⁶ cells' intracorporeal hADSC injection after 12 hours of penile clamping (group II) were euthanized after 2 and 4 weeks of observation. The last group consisted of two rats without any treatment or model (group III). Following euthanasia, penises were harvested for TGFβ₁ and collagen type I measurement using ELISA. Statistical analysis using independent-sample t-tests was done with SPSS 21.0.

Results

Penile TGFβ₁ concentration in the treatment group was significantly lower in the second and fourth weeks of observation (p₂=0.004, p₄=0.003), and collagen type I was significantly lower in the second and fourth weeks (p₂=0.003, p₄=0.011).

Conclusion

Intracorporeal hADSC injection limited the fibrosis process in a priapism model. Although the mechanism was unclear, it may be related to the potential of hADSCs to produce various growth factors that could limit TGFβ₁ and collagen production.

Transplantation of adipose-derived stem cells overexpressing inducible nitric oxide synthase ameliorates diabetes mellitus-induced erectile dysfunction in rats

Background

Erectile dysfunction is a major complication of diabetes mellitus. Adipose-derived stem cells (ADSCs) have attracted much attention as a promising tool for the treatment of diabetes mellitus-induced erectile dysfunction (DMED). Inducible nitric oxide synthase (iNOS) plays an important role in protecting penile tissues from fibrosis. The aim of this study was to determine the efficacy of ADSCs overexpressing iNOS on DMED in rats.

Methods

ADSCs were isolated and infected with adenovirus overexpressing iNOS (named as ADSCs-iNOS). The expression of iNOS was detected using western blot analysis and real-time PCR. Rats were randomly assigned into five groups: control group, DMED group, ADSCs group, ADSCs-EGFP group and ADSCs-iNOS group. 5 × 10⁵ cells were given once via the intracorporal route. Two weeks after treatment, erectile function was assessed by electrical stimulation of the cavernous nerve. Penile tissues were obtained and evaluated at histology level.

Results

We found that ADSCs-iNOS had significantly higher expression of iNOS at mRNA and protein levels and generated more nitric oxide (NO). ADSCs-iNOS reduced collagen I and collagen IV expression of corpus cavernosum smooth muscle cells (CCSMCs) in cell co-culture model. Transforming growth factor-β1 expression in CCSMCs reduced following co-culture with ADSCs-iNOS. Injection of ADSCs-iNOS significantly ameliorated DMED in rats and decreased collagen/smooth muscle cell ratio of penile tissues. Moreover, elevated NO and cyclic guanosine monophosphate concentrations were detected in penile tissues of ADSCs-iNOS group.

Conclusion

Taken together, ADSCs-iNOS significantly improved erectile function of DMED rats. The therapeutic effect may be achieved by increased NO generation and the suppression of collagen I and collagen IV expression in the CCSMCs to decrease penile fibrosis.

The anti-inflammatory and anti-fibrotic effects of tadalafil in thioacetamide-induced liver fibrosis in rats

Liver fibrosis is a health concern that leads to organ failure mediated via production of inflammatory cytokines and fibrotic biomarkers. This study aimed to explore the protective effect of tadalafil, a phosphodiesterase-5 inhibitor, against thioacetamide (TAA)-induced liver fibrosis. Fibrosis was induced by administration of TAA (200 mg/kg, i.p.) twice weekly for 6 weeks. Serum transaminases activities, liver inflammatory cytokines, fibrotic biomarkers, and liver histopathology were assessed. TAA induced marked histopathological changes in liver tissues coupled with elevations in serum transaminases activities. Furthermore, hepatic content of nitric oxide and tumor necrosis factor-alpha, interleukin-6, and interleukin-1 beta were elevated, together with a reduction of interleukin-10 in the liver. In addition, TAA increased hepatic contents of transforming growth factor-beta, hydroxyproline, alpha-smooth muscle actin, and gene expression of collagen-1. Pretreatment with tadalafil protected against TAA-induced liver fibrosis, in a dose-dependent manner, as proved by the alleviation of inflammatory and fibrotic biomarkers. The effects of tadalafil were comparable with that of silymarin, a natural antioxidant, and could be assigned to its anti-inflammatory and anti-fibrotic properties.

The two phases of the clinical validation of preclinical translational mechanistic research on PDE5 inhibitors since Viagra's advent. A personal perspective

The FDA approval of Viagra (sildenafil) for the on demand treatment of erectile dysfunction (ED) through relaxation of the corporal and cavernosal vascular smooth muscle that results in an increase in blood flow to the corporal tissues stemmed from 2 decades of research, mainly at academic centers. This culminated in the finding of the nitric oxide/cGMP pathway as the mediator of penile erection, followed by some years of basic studies and clinical validation at Pfizer. Further on, new translational laboratory and animal research from our group initiated a second phase when we proposed an alternative therapeutic schedule and mechanism of action for PDE5 inhibitors (PDE5i) in both corporal veno-occlusive dysfunction (CVOD) and Peyronie's disease (PD), specifically, continuous long-term administration (CLTA) to achieve sustained levels of cGMP within the penis. Due to the extended half-life of the long-acting PDE5i, tadalafil, this new alternative encompasses preferentially daily administration, although shorter half-life PDE5i, like sildenafil and vardenafil work too, depending on the duration, dose, and frequency of their administration This novel use was initially supported by showing the antifibrotic/antioxidant effects of nitric oxide and cGMP, produced by the induction of iNOS, as a mechanism of defense against collagen deposition in the localized fibrotic plaque of PD in an avascular tissue, the tunica albuginea. Our studies on iNOS and the progressive diffuse fibrosis occurring in the smooth muscle in CVOD, led to proposing the CLTA of PDE5i for maintaining sustained cGMP levels both in PD and in CVOD in order to halt or regress the penile fibrosis. In CVOD, we showed that PDE5i protect the corporal smooth muscle and reduce myofibroblast activation and number, counteracting the underlying corporal tissue pathology that causes CVOD, and potentially ameliorating long-term CVOD or even curing it. This review is focused on this novel PDE5i anti-fibrotic therapeutic concept.

Phosphodiesterase type 5 and cancers: progress and challenges

Cancers are an extraordinarily heterogeneous collection of diseases with distinct genetic profiles and biological features that directly influence response patterns to various treatment strategies as well as clinical outcomes. Nevertheless, our growing understanding of cancer cell biology and tumor progression is gradually leading towards rational, tailored medical treatments designed to destroy cancer cells by exploiting the unique cellular pathways that distinguish them from normal healthy counterparts. Recently, inhibition of the activity of phosphodiesterase type 5 (PDE5) is emerging as a promising approach to restore normal intracellular cyclic guanosine monophosphate (cGMP) signalling, and thereby resulting into the activation of various downstream molecules to inhibit proliferation, motility and invasion of certain cancer cells. In this review, we present an overview of the experimental and clinical evidences highlighting the role of PDE5 in the pathogenesis and prevention of various malignancies. Current data are still not sufficient to draw conclusive statements for cancer patient management, but could provide further rational for testing PDE5-targeting drugs as anticancer agents in clinical settings.

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

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

Clinical and preclinical treatment of urologic diseases with phosphodiesterase isoenzymes 5 inhibitors: an update

Phosphodiesterase isoenzymes 5 inhibitors (PDE5-Is) are the first-line therapy for erectile dysfunction (ED). The constant discoveries of nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) cell-signaling pathway for smooth muscle (SM) control in other urogenital tracts (UGTs) make PDE5-Is promising pharmacologic agents against other benign urological diseases. This article reviews the literature and contains some previously unpublished data about characterizations and activities of PDE5 and its inhibitors in treating urological disorders. Scientific discoveries have improved our understanding of cell-signaling pathway in NO/cGMP-mediated SM relaxation in UGTs. Moreover, the clinical applications of PDE5-Is have been widely recognized. On-demand PDE5-Is are efficacious for most cases of ED, while daily-dosing and combination with testosterone are recommended for refractory cases. Soluble guanylate cyclase (sGC) stimulators also have promising role in the management of severe ED conditions. PDE5-Is are also the first rehabilitation strategy for postoperation or postradiotherapy ED for prostate cancer patients. PDE5-Is, especially combined with α-adrenoceptor antagonists, are very effective for benign prostatic hyperplasia (BPH) except on maximum urinary flow rate (Q max ) with tadalafil recently proved for BPH with/without ED. Furthermore, PDE5-Is are currently under various phases of clinical or preclinical researches with promising potential for other urinary and genital illnesses, such as priapism, premature ejaculation, urinary tract calculi, overactive bladder, Peyronie's disease, and female sexual dysfunction. Inhibition of PDE5 is expected to be an effective strategy in treating benign urological diseases. However, further clinical studies and basic researches investigating mechanisms of PDE5-Is in disorders of UGTs are required.

Nonsurgical Interventions for Peyronie's Disease: Update as of 2016

Peyronie's disease (PD) is a debilitating condition of the penis that leads to significant pain, erectile dysfunction, and emotional distress in men. PD is likely underreported due to lack of knowledge of the disease and the absence of well-established available treatments. Surgical treatment can lead to sustained improvements, but is often associated with penile shortening and places the patient at risk for perioperative morbidity. Nonsurgical management has been studied for several years as an alternative to surgery for men with PD. Currently, much of the data on nonsurgical management is conflicting, with only one treatment that has been recently approved by the US Food and Drug Administration. Significant effort has been devoted to advancing non-surgical treatments for PD that can be implemented outside of the operating room. This review aims to describe the research behind current nonsurgical therapies for PD and to highlight the recent advances that have been made within the last three years.

The Efficacy of Medical Treatment of Peyronie's Disease: Potassium Para-Aminobenzoate Monotherapy vs. Combination Therapy with Tamoxifen, L-Carnitine, and Phosphodiesterase Type 5 Inhibitor

PURPOSE

This study was designed to evaluate the efficacy of medical treatment of Peyronie's disease.

MATERIALS AND METHODS

A total of 109 patients with Peyronie's disease who had been treated from January 2011 to December 2014 were retrospectively reviewed in this study. Forty-four patients (Group 1) were treated with 12 mg of potassium para-aminobenzoate daily. Sixty-five patients (Group 2) were treated with combination therapy: tamoxifen (20 mg) and acetyl-L-carnitine (300 mg) twice daily in addition to a phosphodiesterase type 5 inhibitor. Ability to perform sexual intercourse, pain during erection, size of plaque, and penile curvature angle were assessed.

RESULTS

In Group 1, 30 of 44 patients (68.2%) discontinued treatment within 12 weeks, while 5 patients (7.7%) in Group 2 discontinued treatment. Pain during erection and plaque size were improved in both groups but showed no statistical difference due to the high dropout rate in Group 1. In both groups, penile curvature was improved, but demonstrated no statistical difference between the treatment groups. However, combination therapy demonstrated a better response rate in patients whose penile curvature angle was less than 30° (44.4% vs. 79.1%, p=0.048). The rate of successful sexual intercourse was significantly higher in Group 2 (42.8% vs. 78.3%, p=0.034). The number of patients who underwent surgical correction despite medical treatment was significantly higher in Group 1 (35.7% vs. 13.3%, p=0.048).

CONCLUSIONS

Early medical combination therapy in Peyronie's disease may present better results in patients whose curvature angle is less than 30°.

The myofibroblast, a key cell in normal and pathological tissue repair

Myofibroblasts are characterized by their expression of α-smooth muscle actin, their enhanced contractility when compared to normal fibroblasts and their increased synthetic activity of extracellular matrix proteins. Myofibroblasts play an important role in normal tissue repair processes, particularly in the skin where they were first described. During normal tissue repair, they appear transiently and are then lost via apoptosis. However, the chronic presence and continued activity of myofibroblasts characterize many fibrotic pathologies, in the skin and internal organs including the liver, kidney and lung. More recently, it has become clear that myofibroblasts also play a role in many types of cancer as stromal or cancer-associated myofibroblast. The fact that myofibroblasts are now known to be key players in many pathologies makes understanding their functions, origin and the regulation of their differentiation important to enable them to be regulated in normal physiology and targeted in fibrosis, scarring and cancer.

Therapeutic advances in the treatment of Peyronie's disease

Peyronie's disease (PD) is an under-diagnosed condition with prevalence in the male population as high as 9%. It is a localized connective tissue disorder of the penis characterized by scarring of the tunica albuginea. Its pathophysiology, however, remains incompletely elucidated. For the management of the acute phase of PD, there are currently numerous available oral drugs, but the scientific evidence for their use is weak. In terms of intralesional injections, collagenase clostridium histolyticum is currently the only Food and Drug Administration-approved drug for the management of patients with PD and a palpable plaque with dorsal or dorsolateral curvature >30°. Other available intralesional injectable drugs include verapamil and interferon-alpha-2B, however, their use is considered off-label. Iontophoresis, shockwave therapy, and radiation therapy have also been described with unconvincing results, and as such, their use is currently not recommended. Traction therapy, as part of a multimodal approach, is an underused additional tool for the prevention of PD-associated loss of penile length, but its efficacy is dependent on patient compliance. Surgical therapy remains the gold standard for patients in the chronic phase of the disease. In patients with adequate erectile function, tunical plication and/or incision/partial excision and grafting can be offered, depending on degree of curvature and/or presence of destabilizing deformity. In patients with erectile dysfunction non-responsive to oral therapy, insertion of an inflatable penile prosthesis with or without straightening procedures should be offered.

Collagenase Clostridium histolyticum for the Treatment of Peyronie's Disease: The Development of This Novel Pharmacologic Approach

INTRODUCTION

The conception of collagenase Clostridium histolyticum (CCH) as treatment for Peyronie's disease (PD) was a vital first step in providing a nonsurgical, minimally invasive FDA-approved treatment for men with PD.

AIM

To review the origins, clinical research history, and ultimately FDA approval of collagenase as PD treatment.

METHODS

A PubMed search using (Peyronie's or Peyronie) AND collagenase, and limited to clinical research studies, returned nine papers that were examined in the current review.

RESULTS

Collagenase as a PD treatment arose in response to a lack of effective nonsurgical treatments and the incomplete understanding of underlying PD etiology. Awareness of dense collagen in PD scarring and parallel initial exploration of collagenase to treat herniated lumbar discs coincided with and inspired laboratory-based investigation of collagenase effects on excised PD plaque tissue. The foundational conceptual work and the critical development of purified injectable collagenase allowed the pursuit of clinical studies. Progression of clinical studies into large-scale robust trials culminated in two important outcomes: development of the first validated, PD-specific measure of psychosexual function, the Peyronie's Disease Questionnaire, and the first FDA-approved treatment for PD.

CONCLUSIONS

Collagenase therapy began as an attempt to modify the structure of PD-related tunica albuginea scarring, despite the lack of a fundamental understanding of the scar's origin. If we wish to advance PD treatment beyond this first effective step, the future needs to bring us full circle to the starting point: We need a greater understanding of the control of collagen deposition and wound healing in men with PD.

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.

Stem cell treatment of erectile dysfunction

Erectile Dysfunction (ED) is a common disease that typically affects older men. While oral type-5 phosphodieserase inhibitors (PDE5Is) represent a successful first-line therapy, many patients do not respond to this treatment leading researchers to look for alternative treatment modalities. Stem cell (SC) therapy is a promising new frontier for the treatment of those patients and many studies demonstrated its therapeutic effects. In this article, using a Medline database search of all relevant articles, we present a summary of the scientific principles behind SCs and their use for treatment of ED. We discuss specifically the different types of SCs used in ED, the methods of delivery tested, and the methods attempted to enhance SC therapy effect. In addition, we review the current preclinical literature on SC therapy for ED and present a summary of its findings in addition to the single clinical trial published.

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.

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

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

The anti-inflammatory and antifibrosis effects of anthocyanin extracted from black soybean on a Peyronie disease rat model

OBJECTIVE

To evaluate the potential of anthocyanin as a supplement for the treatment of Peyronie disease (PD) by examining the anti-inflammatory and antifibrosis activities of anthocyanin in a PD animal model.

MATERIALS AND METHODS

We performed the preliminary experiment to confirm the plaque formation of tunica albuginea (TA). Six animals received fibrin (TISSEEL VH Sealer; Baxter, Glendale, CA; 30 μL each of human fibrin and thrombin solutions) injections into the TA. After 2 weeks, PD-like plaque formation was confirmed by Masson trichrome staining in preliminary experimental animal group. A PD rat model was made by intratunical injection of fibrin. Experimental animals were divided into 3 groups as follows: control group (n = 8), PD group (n = 8), and anthocyanin-treated group (n = 8) that received anthocyanin at 50 mg/kg twice a day for 4 weeks using orogastric tubes. After 4 weeks, penile tissue was collected to perform Masson trichrome and transforming growth factor (TGF)-β1 staining.

RESULTS

We confirmed PD-like plaque formation by Masson trichrome stain 2 weeks after fibrin injection. The ratio of smooth muscle cells in the corpus cavernosum in the PD group was significantly lower than that of the control group (P <.05). The PD group showed strong TGF-β1 immunoreactivity with increased expression in the collagenous connective tissues and fibroblasts around the TA.

CONCLUSION

We confirmed PD-like plaque formation after 2 weeks of fibrin injections into the TA. This is the first study to suggest that anthocyanin extracted from black soybean may have anti-inflammatory and antifibrotic effects for penile plaque formation in rat PD models.

The role of intrinsic pathway in apoptosis activation and progression in Peyronie's disease

Peyronie's disease (PD) is characterized with formation of fibrous plaques which result in penile deformity, pain, and erectile dysfunction. The aim of this study was to investigate the activation of the intrinsic apoptotic pathway in plaques from PD patients. Tunica albuginea from either PD or control patients was assessed for the expression of bax, bcl-2 and caspases 9 and 3 using immunohistochemistry and by measurement of apoptotic cells using TUNEL assay. Bax overexpression was observed in metaplastic bone tissue, in fibroblasts, and in myofibroblast of plaques from PD patients. Little or no bcl-2 immunostaining was detected in samples from either patients or controls. Caspase 3 immunostaining was very strong in fibrous tissue, in metaplasic bone osteocytes, and in primary ossification center osteoblasts. Moderate caspase 9 immunostaining was seen in fibrous cells plaques and in osteocytes and osteoblasts of primary ossification centers from PD patients. Control samples were negative for caspase 9 immunostaining. In PD patients the TUNEL immunoassay showed intense immunostaining of fibroblasts and myofibroblasts, the absence of apoptotic cells in metaplasic bone tissue and on the border between fibrous and metaplastic bone tissue. Apoptosis occurs in stabilized PD plaques and is partly induced by the intrinsic pathway.

Discovery of 3-(4-hydroxybenzyl)-1-(thiophen-2-yl)chromeno[2,3-c]pyrrol-9(2H)-one as a phosphodiesterase-5 inhibitor and its complex crystal structure

Phosphodiesterase-5 (PDE5) inhibitors have been approved for the treatment of erectile dysfunction and pulmonary hypertension, but enthusiasm on discovery of PDE5 inhibitors continues for their potential new applications. Reported here is discovery of a series of new PDE5 inhibitors by structure-based design, molecular docking, chemical synthesis, and enzymatic characterization. The best compound, 3-(4-hydroxybenzyl)-1-(thiophen-2-yl)chromeno[2,3-c]pyrrol-9(2H)-one (57), has an IC₅₀ of 17 nM against the PDE5 catalytic domain and good selectivity over other PDE families. The crystal structure of the PDE5 catalytic domain in complex with 57 was determined at 2Å resolution and showed that 57 occupies the same pocket as other PDE5 inhibitors, but has a different binding pattern in detail. On the basis of the binding pattern of 57, a novel scaffold can be proposed as a candidate of PDE inhibitors.

Daily dosing of PDE5 inhibitors: where does it fit in?

To provide a critical contemporary review of daily PDE5-inhibitor (PDE5-I) use in urological and nonurological conditions. PDE5-Is can be taken up to once a day. However, at present only tadalafil is approved for use in both erectile dysfunction (ED) and benign prostate hyperplasia (BPH) with lower urinary tract symptoms (LUTS). Evolving research in penile rehabilitation, Peyronie's disease, male infertility, pulmonary arterial hypertension, muscular dystrophy and Raynaud's phenomenon shows these therapeutic areas may also benefit from PDE5i therapy. This review examines the role of chronic PDE5 inhibition in ED, BPH-LUTS and other therapeutic targets which may shape our clinical practice in the years to come.

Peyronie's disease: epidemiology, diagnosis, and management

OBJECTIVE

Peyronie's disease (PD) is a progressive fibrotic disorder of the penis that is characterized by formation of collagen plaques on the tunica albuginea of the penis that may result in penile deformity, pain (typically early in the disease course), and often occurs in conjunction with erectile dysfunction. This review's purpose is to raise awareness of PD among primary care physicians, who are likely to provide the initial diagnosis and information to patients.

METHODS

PubMed was searched for articles related to epidemiology, diagnosis, and management of PD. Reference lists of relevant articles were also examined for further pertinent research. Following the goals of this review, references were selected based on their appropriateness for a primary care audience.

RESULTS

The symptoms of PD may physically limit intercourse and impose a severe physical and psychological burden. The course of PD includes an early 'inflammatory' phase that may last 1-18 months and a subsequent 'stable' phase. In the early phase, patients may experience penile pain as the tunical plaque develops. During the stable phase, the plaque becomes more organized, penile curvature stabilizes, and the pain usually subsides. Currently, there are no US Food and Drug Administration approved therapies that have shown significant efficacy for PD. Nonsurgical treatment options are often used to manage PD with variable success. Most studies of nonsurgical management of PD are small, poorly controlled, and include patients in variable disease stages. Surgical treatment of PD is reserved for stable patients with erectile dysfunction and penile deformity that impairs sexual function.

CONCLUSION

PD is frequently undiagnosed. Even when PD is correctly identified, choice of treatment is problematic, based on the limited currently available clinical data demonstrating clinical benefits associated with treatment. Newer medications in clinical testing seem to offer some potential benefit for men with PD, though further research is necessary.

The non-surgical treatment of peyronie disease: 2013 update

Peyronie disease is a common cause of penile deformity and sexual dysfunction. Although surgery is regarded as the definitive management for this condition, there are many medical and minimally invasive therapies available, with widely varying efficacy reported in the literature. The purpose of this review is to describe the current state-of-the-art for each of the most commonly used as well as several developing non-surgical treatments. Further, we hope to offer perspectives that will aid practitioners in deciding among these treatments that are either already in use or have the potential to be used as alternatives to surgery in the management of this frustrating disease.