Cell culture of Peyronie's disease plaque and normal penile tissue

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.

Drugs of the future for Peyronie's disease

With the increasing awareness of Peyronie's disease (PD), the interest in new concept medications to treat the disorder is escalating. Profibrogenic factors such as transforming growth factor (TGF)-beta1, endothelin (ET-1), connective tissue growth factor (CTGF), angiotensin (Ang) II and platelet derived growth factor (PDGF), all appear to be involved in the pathogenesis of PD. β-Thymosins, pirfenidone, nitric oxide (NO) donors, phosphodiesterase (PDE)-5 inhibitors, matrix metalloproteinases (MMPs)/anti-tissue inhibitor of metalloproteinases (TIMP)-1 reduce collagen synthesis, while decorin, follistatin, and Smad 7 exert antifibrotic effects; all have been proposed for the treatment of PD. Alternative and/or novel approaches for the treatment of PD are needed in part because of the recognized multifactorial etiology of this complex disorder. A comprehensive approach for translating available experimental information into clinically effective drug trials for the treatment of PD is needed. We propose a multi-faceted approach for drug development to generate novel drug products for the treatment of PD.

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

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

p53-Associated Parkin-like cytoplasmic protein (Parc) short-interfering RNA (siRNA) alters p53 location and biology of Peyronie's disease fibroblasts

OBJECTIVE • To evaluate the impact of p53-associated Parkin-like cytoplasmic protein (Parc) short-interfering RNA (siRNA) on the location of p53 as well as the biology of Peyronie's disease (PD) plaque-derived fibroblasts after Parc knockdown. PATIENTS AND METHODS • Plaque tissue was excised from men with stable PD undergoing penile reconstructive surgery and used to produce cultured PD plaque-derived fibroblasts. • Immunofluorescence (IF) and reverse transcription-polymerase chain reaction (RT-PCR) were then used to define the location of p53 and Parc before and after siRNA. • Nuclear fractionation studies were used to assess the chronology of translocation of p53 from cytoplasm to nucleus on Parc knockdown. • The terminal transferase dUTP Nick end labelling (TUNEL) assay was used to assess the apoptotic indices of the PD fibroblasts after Parc knockdown. RESULTS • IF and PCR showed high cytoplasmic levels of p53 and Parc before siRNA. On IF, there was little or no p53 present within the nucleus before Parc knockdown. • After Parc siRNA, IF showed translocation of p53 to the fibroblast nucleus, while Parc levels dropped significantly, but what Parc remained was confined to the cytoplasm with none present in the nucleus. • Nuclear fractionation studies using RT-PCR confirmed this translocation phenomenon and showed the chronology of the event. All p53 had moved from the cytoplasm to the nucleus within 16 h of Parc siRNA. • On TUNEL assay, apoptotic indices increased dramatically after Parc siRNA. CONCLUSIONS • These data prove that Parc is a cytoplasmic anchor for p53 in PD plaque-derived fibroblasts and may be the primary cause of the stabilization and defunctionalization of p53 in these cells. • These findings support Parc as a novel target for PD pharmacotherapy, perhaps using human siRNA technologies once commercially available.

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

INTRODUCTION

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

AIM

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

METHODS

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

MAIN OUTCOME MEASURES

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

CONCLUSIONS

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

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

INTRODUCTION

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

AIM

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Erectile dysfunction and Peyronie's disease in patient with retroperitoenal fibrosis

OBJECTIVE

The aim of this study is to determine the sexual dysfunction in patient with retroperitoneal fibrosis (RPF) and also we explored probability of Peyronie's disease (PD) in this patient group and to compare this with the controls.

MATERIALS AND METHODS

Ten of 17 male RPF patients formed the basis of this study. Patient's age, concomitant diseases were recorded. The diagnosis of PD was based on a palpable penile plaque or acquired penile curvature. Age-matched 88 patients who were admitted to our outpatient clinic with elevated PSA level served as the control group. All patients were asked to complete the IIEF-5 questionnaire. The severity of the erectile dysfunction (ED) was classified into four categories: severe (5-7), moderate (8-16), mild (17-21), and no ED (22-25). Concomitant systemic diseases were recorded. Statistical analyses were done by the Fisher's exact test and an unpaired-sample t-test.

RESULTS

Patients with severe ED or no sexual intercourse in the study group and the control group during the study period were found to be 7 and 14, respectively. The median IIEF-5 score in RPF patients and the control group was 9.8 (min: 5 to max: 23) and 19 (min: 5 to max: 25), respectively. The differences between groups were statistically significant (P = 0.002). In particular, ED was reported in eight RPF patients (80%) which was severe in six (60%) and moderate in two (20%). ED was reported in 45 patients in the control group (51%) which was severe in 14 (15.9%), mild in 25 (28.4%), and moderate in six (6.8%). Patients with RPF had a significant tendency for severe ED compared with the control group (P = 0.0042). Two patients in the RPF group (20%) and one patient in the control group (1.1%) were found to have a penile plaque (P = 0.0279). Relative risk for developing a penile plague was found to be 0.8 in RPF.

CONCLUSION

RPF patients are found to be more prone to developing ED. Penile plaque formation was identified in RPF patients, which may be presumed to relate to the pathological changes of the RPF process, but it remains unclear that these patients demonstrate a higher incidence of plaque formation than the normal population.

Identification of potential biomarkers of Peyronie's disease

AIM

To identify proteins that are differentially expressed in cells derived from normal and diseased tunica albuginea (TA) as related to Peyronie's disease (PD).

METHODS

Cells with characteristics of fibroblasts were isolated from two tissue sources. Those from the plaque of patients with PD were designated as PT cells, and those from the normally-appearing TA of the same patients were designated as NT cells. Messenger RNAs of these cells were analyzed by real-time polymerase chain reaction (RT-PCR) for the expression of monocyte chemoattractant protein 1 (MCP-1). Crude protein lysates were analyzed by surface-enhanced laser desorption/ionization mass spectrometry (SELDI-MS) with IMAC30-Cu, CM10, and H50 chips. Each lysate was then separated into six fractions, which were further analyzed by SELDI-MS.

RESULTS

RT- PCR analysis showed that PT cells expressed higher levels of MCP-1 than their counterpart NT cells. SELDI-MS analysis showed that the crude protein lysates of all four cell strains produced similar and reproducible protein profiles on IMAC30-Cu and CM10 chips. Additional SELDI-MS analyses with the fractionated lysates detected three proteins of 11.6 kDa, 14.5 kDa, 22.6 kDa that were upregulated in PT cells and two proteins of 6.3 kDa and 46.9 kDa that were downregulated in PT cells.

CONCLUSION

MCP-1, which is often involved in tissue fibrosis, was expressed at higher levels in PT than that in NT cells. Five potential biomarkers for PD were identified by SELDI-MS analysis.

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

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

Functional Tissue Engineering of Autologous Tunica Albuginea: A Possible Graft for Peyronie’s Disease Surgery

OBJECTIVES

The aim of the present study was to generate a tissue engineered type of mechanically stable graft suitable for surgical replacement of the tunica albuginea penis.

METHODS

Porcine fibroblasts isolated from open fascia biopsies were seeded on decellularized collagen matrices and then cultivated in a bioreactor under continuous multiaxial stress for up to 21 days (n=12). Static cultures without mechanical stress served as controls. Cell proliferation, cell alignment, and de novo synthesis of extracellular matrix proteins (proteoglycans, procollagen I, elastin) in these grafts was evaluated by hematoxylin-eosin, pentachrome, and immuno-staining. Additionally, the enzymatic isolation of porcine fibroblasts from X4mm skin punch biopsies (n=8) was evaluated.

RESULTS

Mechanically strained cultures of fibroblasts showed a homogeneous multilayer matrix infiltration and a regular cell alignment in the direction of strain axis after 7 days, as well as a de novo production of extracellular matrix proteins compared to the static control. A large amount of viable fibroblasts was easily obtained from small skin punch biopsies.

CONCLUSION

This study shows that continuous multiaxial stimuli improve proliferation and extracellular matrix synthesis of mature fibroblasts reseeded on a biological matrix making this a feasible autologous tissue engineered graft for penile surgery. For the clinical setting fibroblasts harvested from small skin biopsies can be a comfortable cell source.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Fibrin as an inducer of fibrosis in the tunica albuginea of the rat: a new animal model of Peyronie's disease

OBJECTIVES

To investigate the role of fibrin in inducing fibrosis in the tunica albuginea (TA) of the rat penis, to develop a new animal model for Peyronie's disease (PD).

MATERIALS AND METHODS

The TA of rats (five per group per period) were injected with either saline, fibrin, transforming growth factor-beta1 (TGF-beta1) or TGF-beta1 plus fibrin; the rats were killed at 1, 3, and 6 weeks after injection. Images were analysed quantitatively from tissue sections stained for collagen (Masson trichrome), fibrin (Verhoeff's stain) and elastin (Hart's stain), and immunostained for TGF-beta1, inducible nitric oxide synthase (iNOS), heme oxygenase 1 (HO1), alpha-smooth muscle actin (ASMA), apoptosis (TUNEL) and plasminogen activator inhibitor (PAI). Collagen fibre organization was characterized by electron microscopy. Human PD plaque tissue and normal human TA were assayed for fibrin by immunohistochemistry in nine samples.

RESULTS

At 1 week after injection of fibrin into the rat TA, only oedema was present; at 3 weeks, the oedema developed into a characteristic fibrotic PD-like plaque. The injection of TGF-beta1 into the TA also induced oedema in the TA at 1 and 3 weeks but there was very little evidence of a recognisable plaque at either time. Injection with TGF-beta1 plus fibrin resulted in oedema at 1 week but at 3 weeks there was a smaller plaque than with fibrin only. At 6 weeks the induced plaques in the fibrin-only and fibrin + TGF-beta1 groups persisted, and were comparable with those elicited at this time by TGF-beta1 alone. The control animals showed no pathology at any of the sample times. At 3 weeks the PD plaque induced by injection with fibrin alone had not only greater expression of TGF-beta1 than the TA of the animals receiving TGF-beta1 alone, but also greater levels of other markers of fibrosis, e.g. HO1 (reactive oxygen species), ASMA (presence of myofibroblasts), apoptosis, and PAI (inhibitor of fibrinolysis). iNOS, a known antifibrotic agent, was also increased. In human PD plaque tissue, fibrin was detected by immunohistochemistry in all nine specimens.

CONCLUSIONS

These results suggest that fibrin, when introduced into the TA of the rat penis, acts as a potential profibrotic protein, possibly via the local release of TGF-beta1, and induces a plaque not only histologically similar to that induced by TGF-beta1 but to that of the human condition. Because fibrin can extravasate from the blood into the human TA after an injury to the TA, and because fibrin persists in the plaque tissue, we hypothesise that fibrin may play a key role in the pathogenesis of human PD.

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

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

Gene expression in Peyronie's disease

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

Peyronie's disease cell culture models: phenotypic, genotypic and functional analyses

Peyronie's disease is a fibromatosis of the tunica albuginea. While trauma is believed to be the inciting event, the exact pathophysiology of this condition is unknown. In vitro analysis of cell biology can shed light on the pathogenesis of medical conditions and has been used for many decades as a research tool. We have established a cell culture model, which we have used to study the pathobiology of cells derived from Peyronie's disease plaque tissue. In 10 separate cell cultures derived from different individuals, these cells have demonstrated consistent phenotypic, genotypic and functional alterations. In neither of the control cell cultures, neonatal foreskin fibroblasts and normal tunica-derived fibroblasts have any of the above aberrations been demonstrated. The cells studied have been shown to be fibroblasts in nature with a sub-population of myofibroblasts present in culture. The Peyronie's disease plaque tissue-derived fibroblasts have demonstrated (i) consistent morphologic transformation (ii) increased S-phase on flow cytometry (iii) decreased dependence on culture medium (iv) cytogenic instability (v) excess production of fibrogenic cytokines and (vi) stabilization and dysfunctionalization of p53. Further refinement of this model and future analyses may permit an increased understanding of the pathogenesis of this condition and allow the development of therapeutic strategies.

The use of betamethasone and hyaluronidase injections in the treatment of Peyronie's disease

OBJECTIVE

The aim of this study was to assess the effect of local injections of betamethasone, hyaluronidase and lidocaine in patients with Peyronie's disease.

MATERIAL AND METHODS

A total of 112 men who had a palpable plaque at the penis and suffered from painful erection and bending of penis was treated with a total of 12 injections containing betamethasone, hyaluronidase and lidocaine. Patients were classified into groups according to the duration of the disease (<6 months, 6-12 months or >12 months) as well as the size of the plaque (<10 mm, 10-20 mm or >20 mm). Pretreatment evaluation of patients and assessment of outcome were based on subjective criteria as well as measurement of the size of the plaque by means of ultrasound. Results were correlated to patients' characteristics.

RESULTS

The overall response rate was 86%. Cure or improvement was noticed in 31% and 55% of patients respectively. Most of the patients (83%) had a duration of disease less than 12 months. Painful erection, bending of penis and plaque were absent in 97%, 32% and 31% of patients, respectively, after treatment. No severe complications were observed. The effect of treatment was strongly related to the duration of disease and the size of the plaque.

CONCLUSIONS

The method is safe, well tolerated by patients and characterized by a high response rate in patients with a history of less than 12 months and a plaque not exceeding 20 mm.

Peyronie's disease: advances in basic science and pathophysiology

Peyronie's disease is an idiopathic, localized connective tissue disorder of the penis that involves the tunica albuginea of the corpus cavernosum and the adjacent areolar space. The tunica albuginea plays an important role in the mechanism of erection. Peyronie's disease is characterized by local changes in the collagen and elastic fiber composition of the tunica albuginea. The formation of fibrotic plaques alters penile anatomy and can cause different degrees of bending, narrowing, or shortening of the penis. Moreover, a significant number of men with Peyronie's disease develop erectile dysfunction. Penile blood flow studies in many patients with Peyronie's disease suggest a strong association with veno-occlusive dysfunction. Although long recognized as an important clinical entity of the male genitalia, the etiology of this disease has remained poorly understood. The following review focuses on recent research on the pathophysiology of Peyronie's disease.

Peyronie's disease is associated with Paget's disease of bone

Peyronie's disease is an idiopathic disorder in which an inflammatory fibrosis occurs in the tunica albuginea of the corpora cavernosa which causes the erect penis to become deformed. Peyronie's disease has a prevalence of 1% in men over age 50 years. Paget's disease of bone is a chronic skeletal disease with areas of increased bone turnover leading to pain, deformity, and in some cases arthritis. Because of a high rate of Peyronie's disease in subjects in a Paget's disease industry-sponsored drug trial, we asked whether there was an association between Peyronie's disease and Paget's disease of bone. We evaluated 61 men with Paget's disease attending our clinic for metabolic bone disease in a tertiary referral hospital, reviewed hospital records of all men discharged from our three hospitals with the diagnosis of Peyronie's disease, and mailed a validated questionnaire about shape of the erect penis to 1500 male members of the Paget Foundation. In the clinic population of men with Paget's disease of bone, 51 of 61 (83.6%) reported having normal erections; 10 patients (16.4%) were impotent. Sixteen of the 51 men (31.4%) had developed a bend or deformity in their erect penis which was confirmed by a urologist's examination to be Peyronie's disease. When the men with Paget's disease with and without Peyronie's disease were compared, there was no difference in their ages, years with Paget's disease, or serum alkaline phosphatase level. Upon medical record review, 1 patient of 262 (0.4%) with Peyronie's disease was found to have Paget's disease of bone. The men with Paget's disease returned their questionnaires for a response rate of 44.8% and reported Peyronie's disease with a prevalence of 14.5%. We suggest that Peyronie's disease is associated with Paget's disease of bone. Furthermore, we suggest that Peyronie's disease may be a previously unrecognized complication of Paget's disease of bone.

Proposal: trauma as the cause of the Peyronie's lesion

PURPOSE

We define the cause of the occurrence of Peyronie's disease.

MATERIALS AND METHODS

Clinical evaluation of a large number of patients with Peyronie's disease, while taking into account the pathological and biochemical findings of the penis in patients who have been treated by surgery, has led to an understanding of the relationship of the anatomical structure of the penis to its rigidity during erection, and how the effect of the stress imposed upon those structures during intercourse is modified by the loss of compliance resulting from aging of the collagen composing those structures. Peyronie's disease occurs most frequently in middle-aged men, less frequently in older men and infrequently in younger men who have more elastic tissues. During erection, when full tumescence has occurred and the elastic tissues of the penis have reached the limit of their compliance, the strands of the septum give vertical rigidity to the penis. Bending the erect penis out of column stresses the attachment of the septal strands to the tunica albuginea.

RESULTS

Plaques of Peyronie's disease are found where the strands of the septum are attached in the dorsal or ventral aspect of the penis. The pathological scar in the tunica albuginea of the corpora cavernosa in Peyronie's disease is characterized by excessive collagen accumulation, fibrin deposition and disordered elastic fibers in the plaque.

CONCLUSIONS

We suggest that Peyronie's disease results from repetitive microvascular injury, with fibrin deposition and trapping in the tissue space that is not adequately cleared during the normal remodeling and repair of the tear in the tunica. Fibroblast activation and proliferation, enhanced vessel permeability and generation of chemotactic factors for leukocytes are stimulated by fibrin deposited in the normal process of wound healing. However, in Peyronie's disease the lesion fails to resolve either due to an inability to clear the original stimulus or due to further deposition of fibrin subsequent to repeated trauma. Collagen is also trapped and pathological fibrosis ensues.

Regulation of the proliferation and biosynthetic activities of cultured human Peyronie's disease fibroblasts by interferons-alpha, -beta and -gamma

To determine the therapeutic potential of interferon (IFN) treatment for Peyronie's disease, we investigated the effect of human recombinant (hu-r) IFNs on cultured fibroblasts derived from a Peyronie's disease penile plaque. Treatment of cultured fibroblasts with hu-r-IFN-alpha2b, hu-r-IFN-beta-ser17 and hu-r-IFN gamma caused a concentration dependent inhibition of both fibroblast proliferation and collagen production, as well as an increase in collagenase production. Hu-r-IFN-alpha and beta had no effect on fibroblast glycosaminoglycan (GAG) or fibronectin production, while hu-r-IFN-gamma markedly increased both GAG and fibronectin production. These results demonstrate that IFNs, especially IFNs-alpha and beta, exhibit antifibrotic activity on Peyronie's disease fibroblasts and suggest a rationale for using IFNs to treat Peyronie's disease.

Chromosome abnormalities in Peyronie's disease

Peyronie's disease is a localized and progressive fibrosis of unknown etiology that affects the tunica albuginea of the penis. We examined cytogenetically cell cultures derived from plaque, adjacent tunica, dermis and lymphocytes in patients with Peyronie's disease, and compared the results to cell cultures established from the tunica albuginea of control patients. Chromosomal abnormalities were detected in 9 plaque-derived cell cultures from 7 of 12 Peyronie's disease patients (58 per cent). Cells cultured from adjacent tunica, dermis and lymphocytes from the same patients were karyotypically normal, as were cultures derived from control (chordee and penile scar) patients. Chromosomal aberrations consisted of 5 numerical changes and 4 structural rearrangements, and included chromosomal additions (trisomy 7 and trisomy 8), deletions (45X,-Y), reciprocal translocations and inversions or markers. In 2 instances cultures derived from plaque tissue contained 2 independent chromosomal abnormalities. The apparently random chromosomal changes associated with Peyronie's disease suggests that karyotypic instability may be a common feature of cells within the plaque. It presently is unclear whether this finding represents multiple pathways for the development of Peyronie's disease or secondary consequences of Peyronie's disease.