Penile Fibrosis Research Articles

Effects of Chronic Stress on Penile Corpus Cavernosum of Rats

The objective of this study was to investigate structural changes in the penile corpus cavernosum of prepubertal chronically stressed rats. Eight Wistar rats were assigned into the stress group (SG) and were submitted to 2 hours of tube restraint daily, from the fourth to the ninth week of life. Another 7 rats were used as the control group (CG). All animals were weighed weekly. At day 64, animals were sacrificed by anesthetic overdose, blood was collected for testosterone concentration by radioimmunoassay, and penis and adrenal were collected. Adrenal mass index and testosterone serum levels were used to assess the efficacy of the stress stimulus. The surface density of connective tissue and smooth muscle fibers of corpus cavernosum were measured on Masson trichromic-stained slices. Picrosirius red-stained slices were assessed under polarized light for different types of collagen. The Student's t test was applied for mean comparisons, with P < .05 considered significant. Testosterone serum concentrations decreased and adrenal mass index increased, confirming the effectiveness of the stress protocol. Smooth muscle fibers of corpus cavernosum decreased from 14.07% (CG) to 8.98% (SG) (P = .02), and connective tissue increased from 53.66% (CG) to 64.47% (SG) (P = .01). Also, there was a higher level of type I collagen in the SG animals compared with the CG. Stress stimuli induced structural changes in the corpus cavernosum of rats suggestive of penile fibrosis, which may play a role in erection dysfunction.

Penile Duplex Ultrasonography in Men with Peyronie's Disease: Is it Veno‐Occlusive Dysfunction or Poor Cavernosal Arterial Inflow that Contributes to Erectile Dysfunction?

At least 20% of men with Peyronie's disease (PD) suffer from erectile dysfunction (ED). The fundamental mechanism is thought to arise from the progression of penile fibrosis, which was initially limited to the PD plaque within the tunica albuginea. However, recent studies have highlighted the possibility of fibrosis of the cavernosal vessel media wall leading to impairment of arterial inflow. To evaluate the penile duplex ultrasonographic findings in PD of impotent men and to determine whether early features of PD might predict clinical progression. Patient demographic, comorbidities, International Index of Erectile Function-5 scores, surgical intervention, and physical findings were documented. Penile curvature, plaque size, and peak systolic velocity (PSV) and end-diastolic velocity (EDV) on color duplex ultrasonography (CDU) were recorded. We performed a retrospective review of all men presenting with penile curvature and length loss who underwent penile CDU between January 2001 and January 2010. A total of 1,120 men underwent penile CDU during the 10-year period. Complete information was obtained in 810 men; 250 men complained of decreased penile rigidity, while 150 men were unable to sustain erection. Comorbidities were similar between men with PD with and without ED. Tunical thickening (65%) was the most common CDU feature, and mean cumulative calcifications was 24.2 mm(2) (1-360 mm(2) , standard deviation 76). The PSV and EDV on the right cavernosal artery were 14.2 cm/second and 3.5 cm/second, while the left cavernosal artery measurements were 15.1 cm/second and 3.2 cm/second. Multivariate logistic regression model showed strong correlation between plaque size and development of ED. Both veno-occlusive dysfunction and impaired cavernosal arterial inflow were associated with ED. Veno-occlusive dysfunction and impaired cavernosal arterial inflow contributed to the development of ED, and larger plaque size is a strong predictor of surgical intervention.

Alleviation of post-radical prostatectomy cavernosal fibrosis: future directions and potential utility for PDE5 inhibitors

Reversion of cavernosal fibrosis remains a controversial issue. The relative smooth muscle cells' loss that happens with cavernosal nerve damage and their impact on deterioration of erectile function were demonstrated in several studies. Furthermore, chronic ischemia that occurs with aging and medical co-morbidities is associated with the reduction of nitric oxide-cyclic guanosine monophosphate and ultimately cavernosal fibrosis. Despite the encouraging recent results of the role of phosphodiesterase type 5 inhibitors in the prevention of post-prostatectomy erectile dysfunction, debate regarding the exact mechanism of PDE5 inhibitors in prevention, amelioration and reversion of penile fibrosis still exists. Recently, several reports suggested that PDE5 inhibitors may improve endothelial function and decrease arterial stiffness, introducing this class of compounds as potential drugs for the treatment of erectile dysfunction-associated penile fibrosis. In this editorial, we intended to address the role of PDE5 inhibitors as a promising treatment to alleviate or reverse ED associated-cavernosal fibrosis.

Penile Prosthesis Surgery in Patients with Corporal Fibrosis: A State of the Art Review

Penile prosthesis has become one of the most accepted treatment options in patients who do not respond to conservative medical therapies (oral or intracavernous injections). When penile fibrosis is present, this surgery becomes a real surgical challenge even for a skillful surgeon. The aim of this study was to review latest techniques to implant a penile prosthesis in patients with corporal fibrosis. We performed a systematic search in the following databases: PubMed, EMBASE, Cochrane, SCOPUS, and Science Citation Index without any date limits for the terms: "penile prosthesis,""penile fibrosis,""impotence,""fibrosis,""cavernotomes,""downsized prosthesis cylinders,""patient satisfaction,""penile graft," and "vascular graft." We reported in each technique and series data regarding penile size, complication rate, infection rate, technical pitfalls and details, use of additional surgical tools or implanted material (grafts, etc.), patients' satisfaction, and overall success rate. When penile corporal fibrosis is present, this surgery becomes a real surgical challenge even for a skillful surgeon. Over the years, multiple surgical approaches have been suggested to facilitate implantation in this difficult situation. Traditional approaches include the resection of scar tissue, performing extensive corporotomies and the eventually use of grafts to cover the corporal gap. Outcomes can be improved combining the use of techniques for scar incision (extensive wide excision, multiple incisions minimizing excision, corporal counter incisions, corporal excavation technique or Shaeer's technique) and cavernotomes and downsized prosthesis. Surgical strategies like upsizing prosthesis, suspensory ligament release or scrotoplasty must be kept in mind to utilize in this special scenario. Penile prosthesis in a patient with severe corporal fibrosis remains a surgical challenge. There are several techniques and surgical strategies that an implant surgeon should know and manage to minimize complications and improve outcomes.

69 The prevalence and factors associated with depressive symptoms among urban poor men in Selangor, Malaysia

than normal in girth, tortuous and hard. Circumferential biopsy was done and revealed a chronic fibrosis. Case 2 – Scrotal horn: A 37-year-old man had similar procedure as Case 1, and six months later presented with massive penile fibrosis with huge scrotal involvement in horn shape. CT scan of the pelvis revealed extensive fibrosis of the penis and scrotum, involving the whole dartos and cremasteric layer with spared testis. Case 3 – Penile Cellulitis: The last case was a 45 year-oldman who presented with severe cellulitis of the penile post penile injection. He was treated with six weeks antibiotic with 2 weekly review and plan for biopsy. In spite of prolonged antibiotic, his penile skin was not improved (inflamed and edematous), and he requires penile prosthesis. We would like to share difficulty in decision making and managing these post penile augmentation complications. 69 The prevalence and factors associated with depressive symptoms among urban poor men in Selangor, Malaysia K.L. Tan. International Medical University, Malaysia Background: Depression is a significant public health concern and has been projected to be the most important cause of morbidity worldwide. Objectives: The aim of the study was to estimate the prevalence and identify factors associated with depressive symptoms among urbanpoormen in Selangor,Malaysia. Methods: A community based cross-sectional study involving 244 male respondents from Section 8 Kota Damansaradistrict was conducted in February 2010. Data on socio-demographic and lifestyle factors were collected by face-to-face interview using a structured questionnaire by trained staff. The Patient Health Questionnaire (PHQ-9) was used to determine the presence or absence of depressive symptoms among the male respondents. A score of 10 or more was used to calculate for the presence of depressive symptoms. All male respondents aged 18 years and over in the selected households were interviewed. The prevalence of depressive symptoms was estimated. Pearson Chi-Square test was used to test for an association between each factor and depressive symptom with significance set at p< 0.05. Results: The mean age of the respondent was 33.6±12.8 years. Majority was Malay (73.8%), had secondary level education (75.4%), employed (76.2%) and married (62.3%). The prevalence of depressive symptoms among urban poor men was 16.4%. Factors significantly associated with depressive symptoms include marital status, years lived in the area and alcohol consumption. Conclusions: Depressive symptoms among urban poor adult men in Kota Damansara, Selangor was 16.4% and was associated with marital status, years lived in the area and alcohol consumption. jmh Vol. 8, Suppl. 1, S97–S121, April 2011 S121

Pentoxifylline Promotes Recovery of Erectile Function in a Rat Model of Postprostatectomy Erectile Dysfunction

BackgroundCavernous nerve (CN) injury during radical prostatectomy (RP) causes CN degeneration and secondary penile fibrosis and smooth muscle cell (SMC) apoptosis. Pentoxifylline (PTX) is a phosphodiesterase inhibitor that further inhibits multiple cytokine pathways involved in nerve degeneration, apoptosis, and fibrosis. ObjectivesTo evaluate whether PTX enhances erectile function in a rat model of CN injury. Design, Setting and InterventionsForty male Sprague-Dawley rats underwent CN crush injury and were randomized to oral gavage feeding of phosphate-buffered saline (vehicle) or PTX 25, PTX 50, or PTX 100mg/kg per day. Ten animals underwent sham surgery and received vehicle treatment. Treatment continued for 28 d, followed by a wash-out period of 72h. An additional eight rats underwent resection of the major pelvic ganglion (MPG) for tissue culture and examination of direct effects of PTX on neurite sprouting. MeasurementsIntracavernous pressure recording on CN electrostimulation, immunohistologic examination of the penis and the CN distal to the injury site, and length of neurite sprouts in MPG culture. ResultsDaily oral gavage feeding of PTX resulted in significant improvement of erectile function compared to vehicle treatment in all treated groups. After treatment with PTX 50 and PTX 100mg/kg per day, the expression of neuronal nitric oxide synthase in the dorsal penile nerve was significantly higher than in vehicle-treated rats. Furthermore, PTX treatment prevented collagen deposition and SMC loss in the corpus cavernosum. In the CN, signs of Wallerian degeneration were ameliorated by PTX treatment. MPG culture in medium containing PTX resulted in a significant increase of neurite length. ConclusionsPTX treatment following CN injury in rats improved erectile recovery, enhanced nerve regeneration, and preserved the corpus cavernosum microarchitecture. The clinical availability of this compound merits application in penile rehabilitation studies following RP in the near future.

Management of priapism: a case report.

Priapism is a pathologic condition of persistent penile erection in absence of sexual excitation, is a true erectile disorder. Although it is not common, it carries a major significance as possible complications of the disorder include penile fibrosis and permanent erectile dysfunction. All health care professionals should appreciate the importance of priapism and follow current principles of treatment to avert the complications of priapism

Amelioration of Penile Fibrosis: Myth or Reality

Several changes have been reported to occur in the cavernosal tissue and tunica albuginea with aging. The atherosclerosis of the penis that occurs with aging causes a decrease in penile oxygen tension. A reduction in the number of smooth muscle cells (SMCs) has been demonstrated in relation to this change in oxygen tension. Changes in the ratio of penile collagen have also been observed and could explain the decrease in penile elasticity and compliance with aging. Chronic ischemia is therefore associated with fibrosis but also with nitric oxide-cGMP reduction. The sensitivity of the α-adrenoceptors on the SMCs increases with aging. Furthermore, androgen deprivation produces penile tissue atrophy, alterations in dorsal nerve structure, alterations in endothelial morphology, reductions in trabecular SM content, increases in deposition of extracellular matrix, and increases in accumulation of adipocytes in the subtunical region of the corpus cavernosum. All of these modifications can explain the prevalence of erectile dysfunction with aging. The aim of this review is to address the underlying etiology of corporal fibrosis, especially aging, cavernosal nerve damage, androgen deprivation, and tunical fibrosis. Finally, we will address the proposed amelioration and reversal of fibrosis in terms of correcting, at least partially, the relative SMC loss that occurs with aging, diabetes, or cavernosal nerve damage and its impact on prevention of erectile dysfunction-associated cavernosal fibrosis.

Udenafil Enhances the Recovery of Erectile Function and Ameliorates the Pathophysiological Consequences of Cavernous Nerve Resection

Radical prostatectomy is the treatment of choice for prostate cancer patients. Despite the introduction of nerve-sparing surgical techniques, its success is not entirely guaranteed and the majority of patients report compromised erectile function following surgical procedures. This study was performed to investigate the effect of repeated dosing of udenafil, a novel phosphodiesterase type 5 inhibitor, on penile hypoxia and fibrosis induced by bilateral cavernous nerve resection (BCNR) in rats. Thirty male Sprague-Dawley rats (300-320 g) were used in this study. The animals were divided into three groups; group I consisted of sham-operated animals (N = 10), animals in group II underwent BCNR alone (N = 10), and animals in group III were orally treated with 10 mg/kg udenafil b.i.d. for 8 weeks following BCNR (N = 10). The expression of transforming growth factor-beta1, hypoxia-inducible factor-1 alpha, endothelial nitric oxide synthase, neuronal nitric oxide synthase, and endothelin B receptor in penile tissue was examined at gene level. Additionally, erectile function, measured by intracavernous pressure (ICP), and pathological changes in the corpus cavernosum were examined. While fibrosis, apoptosis, and the expression of TGF-beta1, HIF-1 alpha, and ET(B) were significantly increased, and the expression of eNOS and nNOS were significantly decreased in group II, compared with the sham-operated animals, repeated dosing of udenafil significantly ameliorated these changes. Erectile function was profoundly impaired in animals that underwent BCNR alone, and udenafil treatment significantly attenuated this impairment as measured by ICP. These results demonstrate that long-term administration of udenafil ameliorates penile hypoxia and fibrosis induced by cavernous nerve resection. This study also suggests the potential beneficial role of repeated dosing of udenafil in the recovery of erectile function in patients with neuronal erectile dysfunction.

Heart rate reduction with ivabradine improves erectile dysfunction in parallel to decrease in atherosclerotic plaque load in ApoE-knockout mice

ObjectiveTo determine the effect of heart rate reduction with ivabradine on atherosclerotic lesions and erectile dysfunction. MethodsTwo different treatment regimes with ivabradine were applied in wild-type (C57/B6) and ApoE−/−-mice to study effects of ivabradine on erectile function and atherosclerosis in animals with and without present endothelial dysfunction. Preventive effects of ivabradine were evaluated in animals fed a high-cholesterol diet in parallel to treatment with ivabradine (orally via chow, 10mg/kg per day). The other treatment regime started treatment with a high-cholesterol diet for 4 weeks to induce endothelial dysfunction. Thereafter, treatment with ivabradine (orally via chow, 15mg/kg per day) was started in ApoE−/− mice for 3 months. Vital parameters were measured using the tail-cuff method. Erectile function was assessed by pharmacological stimulation of corpora cavernosa in organ bath chambers. Atherosclerotic plaque formation, oxidative stress, eNOS and collagen content were determined. ResultsTreatment with ivabradine significantly reduced heart rate (p<0.01), with no effect on blood pressure. Aortic atherosclerotic lesion size decreased with ivabradine in both treatment regimes (p<0.05). Endothelium-dependent relaxation of corpora cavernosa significantly decreased in ApoE−/−-mice with a restoration by ivabradine in prevention and reversal. Dihydroethidium-stained penile sections (p<0.05) and lipid peroxidase assay (p<0.05) revealed a reduction in superoxide production in ivabradine-treated animals. Penile eNOS-expression increased and collagen content significantly decreased (p<0.01) in ivabradine-treated animals. ConclusionIvabradine improves penile endothelial function by reduction of oxidative stress and penile fibrosis. Beneficial effects were achieved in prevention and manifest endothelial dysfunction.

The actual incidence of papaverine-induced priapism in patients with erectile dysfunction following penile colour Doppler ultrasonography

Penile color Doppler sonography is a valuable method for evaluating erectile dysfunction. However, there are some concerns about the safety of this method due to the intracorporeal pharmacological injection, which may cause priapism as a complication, resulting in penile fibrosis. To evaluate the actual incidence of papaverine-induced priapism in patients with erectile dysfunction (ED) who underwent penile colour Doppler sonography and to determine the safety of this diagnostic tool, a retrospective study was conducted using the database of our institution. A total of 672 men with ED underwent penile color Doppler ultrasonography with the intracorporeal injection of 60 mg papaverine hydrochloride. The patient characteristics of priapism cases were retrospectively evaluated. Priapism in 18 of the 672 patients (2.68%) was successfully treated with blood aspiration, irrigation and injection of an alpha-agonist medication, when needed. Patients with priapism were younger compared with those without priapism; mean age 45 +/- 12.51 (20-68) versus 50.93 +/- 12.04 (17-78) (P < 0.001). Penile Doppler ultrasound is a safe procedure in evaluating erectile dysfunction. The incidence of priapism, which is the most important complication of this procedure, is low and can be managed successfully with conservative approaches.

Penile involvement in Systemic Sclerosis: New Diagnostic and Therapeutic Aspects

Systemic Sclerosis (SSc) is a connective tissue disorder featuring vascular alterations and an immunological activation leading to a progressive and widespread fibrosis of several organs such as the skin, lung, gastrointestinal tract, heart, and kidney. Men with SSc are at increased risk of developing erectile dysfunction (ED) because of the evolution of early microvascular tissutal damage into corporeal fibrosis. The entity of penile vascular damage in SSc patients has been demonstrated by using Duplex ultrasonography and functional infra-red imaging and it is now clear that this is a true clinical entity invariably occurring irrespective of age and disease duration and constituting the ‘‘sclerodermic penis”. Once-daily phosphodiesterase type-5 (PDE5) inhibitors improve both sexual function and vascular measures of cavernous arteries by improving surrogate markers of endothelial dysfunction, that is, plasma endothelin-1 and adrenomedullin levels, which may play a potential role in preventing progression of penile fibrosis and ED. Also, the beneficial effect of long-term PDE5i add-on therapy to SSc therapy in the treatment of Raynaud's phenomenon is described.

Increased adenosine contributes to penile fibrosis, a dangerous feature of priapism, via A 2B adenosine receptor signaling

Priapism is a condition of persistent penile erection in the absence of sexual excitation. Of men with sickle cell disease (SCD), 40% display priapism. The disorder is a dangerous and urgent condition, given its association with penile fibrosis and eventual erectile dysfunction. Current strategies to prevent its progression are poor because of a lack of fundamental understanding of the molecular mechanisms for penile fibrosis in priapism. Here we demonstrate that increased adenosine is a novel causative factor contributing to penile fibrosis in two independent animal models of priapism, adenosine deaminase (ADA)-deficient mice and SCD transgenic mice. An important finding is that chronic reduction of adenosine by ADA enzyme therapy successfully attenuated penile fibrosis in both mouse models, indicating an essential role of increased adenosine in penile fibrosis and a novel therapeutic possibility for this serious complication. Subsequently, we identified that both mice models share a similar fibrotic gene expression profile in penile tissue (including procollagen I, TGF-beta(1), and plasminogen activator inhibitor-1 mRNA), suggesting that they share similar signaling pathways for progression to penile fibrosis. Thus, in an effort to decipher specific cell types and underlying mechanism responsible for adenosine-mediated penile fibrosis, we purified corpus cavernosal fibroblast cells (CCFCs), the major cell type involved in this process, from wild-type mice. Quantitative RT-PCR showed that the major receptor expressed in these cells is the adenosine receptor A(2B)R. Based on this fact, we further purified CCFCs from A(2B)R-deficient mice and demonstrated that A(2B)R is essential for excess adenosine-mediated penile fibrosis. Finally, we revealed that TGF-beta functions downstream of the A(2B)R to increase CCFC collagen secretion and proliferation. Overall, our studies identify an essential role of increased adenosine in the pathogenesis of penile fibrosis via A(2B)R signaling and offer a potential target for prevention and treatment of penile fibrosis, a dangerous complication seen in priapism.-Wen, J., Jiang, X., Dai, Y., Zhang, Y., Tang, Y., Sun, H., Mi, T., Phatarpekar, P. V., Kellems, R. E., Blackburn, M. R., Xia, Y. Increased adenosine contributes to penile fibrosis, a dangerous feature of priapism, via A(2B) adenosine receptor signaling.

Tratamiento y manejo actual de la fase aguda de la enfermedad de Peyronie

The true pathophysiologic nature of Peyronie's disease continues to evolve. This pathology often results in a penile plaque(s), penile deformity, curvature, pain, and erectile dysfunction. Clinically, there are two distinct phases, acute and chronic. The focus of this review will center on the management of the acute phase of Peyronie's disease. While little data exists demonstrating disease resolution, disease stabilization is an important clinical goal for patients as this often allows acceptable sexual function. Thus, medical management during the acute phase of Peyronie's disease is aimed at limiting and stabilizing the degree of penile fibrosis, decreasing penile curvature, and reducing penile pain. In this manuscript we explain different therapies; oral, topical, intralesional injection and others like extracorporeal shockwave (ESWT), radiation and penile traction for acute phase of Peyronie's disease. Although no consensus exists for the treatment of acute phase Peyronie's disease, a majority of patients can achieve stabilization and in some cases regression of their disease with proper medical therapy. The goals of therapy should be discussed extensively with each patient, noting that erectile function will be likely despite some degree of curvature.

Losartan Preserves Erectile Function After Bilateral Cavernous Nerve Injury via Antifibrotic Mechanisms in Male Rats

Angiotensin II is a known mediator of smooth muscle vasoconstriction and fibrosis. It up-regulates thrombospondin-1, a major activator of latent transforming growth factor-beta. Transforming growth factor-beta induces vascular fibrosis via intracellular SMAD signaling pathways. We evaluated the effect of treatment with the angiotensin II type 1 receptor antagonist losartan on erectile function in the rat following bilateral cavernous nerve injury. A total of 36 adult male rats were divided equally into 6 groups, including group 1-sham surgery with cavernous nerve exposure only plus vehicle, group 2-sham surgery plus oral low dose losartan (10 mg/kg per day), group 3-sham surgery plus high dose losartan (40 mg/kg per day), group 4-bilateral cavernous nerve injury (3-minute crush using a hemostat clamp) plus vehicle, group 5-bilateral cavernous nerve injury plus low dose losartan and group 6-bilateral cavernous nerve injury plus high dose losartan. Seven days following surgery erectile function was measured by electrically stimulating the cavernous nerves and monitoring intracavernous pressure. Penile tissue was collected for Western blot analysis of fibronectin, transforming growth factor-beta, thrombospondin-1, alpha-actin, and phosphorylated and total SMAD2 and SMAD3 expression. Erectile function was significantly decreased after bilateral cavernous nerve injury compared with that after sham surgery (p <0.01). Low and high dose losartan preserved erectile function after bilateral cavernous nerve injury compared to that in vehicle controls (p <0.01 and <0.05, respectively). Fibronectin, pSMAD2, pSMAD3, transforming growth factor-beta-1, thrombospondin-1 and alpha-actin expression was up-regulated, and total SMAD2 and SMAD3 expression was down-regulated in the penis after bilateral cavernous nerve injury. Each dose of losartan after bilateral cavernous nerve injury significantly attenuated the up-regulated expression of fibronectin (p <0.01), pSMAD2 (p <0.05) and thrombospondin-1 (p <0.05), and up-regulated total SMAD2 (p <0.05). These data suggest that fibrotic activators in the penis may cause decreased erectile function after bilateral cavernous nerve injury. Angiotensin II type 1 receptor antagonism may counteract this effect and promote erectile function preservation for conditions associated with penile fibrosis.

Mechanisms of Penile Fibrosis

Penile fibrosis has been conceptually identified with the plaque that develops in the tunica albuginea in Peyronie's disease (PD), or with localized processes induced in the corpora cavernosa by ischemic or traumatic events. Recently, it has been proposed that a diffuse, progressive, and milder intracorporal fibrosis, which affects also the media of the penile arteries, is responsible for vasculogenic erectile dysfunction (ED) associated with aging, smoking, diabetes, hypertension, and post-radical prostatectomy. These processes differ in etiology, time course, target cells, and treatment, but have many features in common. To review the literature pertaining to fibrosis in the penis, related to PD and ED. PubMed search for pertinent publications mainly during 2001-2008. This review focuses initially on PD and then deals with studies on ED in animal and cell culture models, discussing some of the pathophysiological similarities between tunical fibrosis in PD and corporal fibrosis in corporal veno-occlusive dysfunction (CVOD), and emerging therapeutic strategies. The role of profibrotic factors, the excessive deposit of collagen fibers and other extracellular matrix, the appearance of a synthetic cell phenotype in smooth muscle cells or the onset of a fibroblast-myofibroblast transition, and in the case of the corporal or penile arterial tissue the reduction of the smooth muscle cellular compartment, are discussed. This histopathology leads either to localized plaques or nodules in penile tissues, or to the diffuse fibrosis causing impairment of tissue compliance that underlies CVOD and arteriogenic ED. The antifibrotic role of the sustained stimulation of the nitric oxide/cyclic guanosine monophosphate pathway in the penis and its possible relevance to exogenous and endogenous stem cell differentiation is also briefly presented. Fibrotic processes in penile tissues share a similar cellular and molecular pathophysiology and common endogenous mechanisms of defense that have inspired novel pharmacological experimental approaches.

Penile prosthesis surgery for the fibrotic penis

Penile fibrosis renders implantation of a penile prosthesis a formidable procedure. Fibrosed corporate cavernosa resist dilation by blunt dilators, mandating the use of force and resulting in a high percentage of complications. This is a report on advances in the field of penile prosthesis surgery for the fibrotic penis through the years 2006 to 2008. In that time, bovine pericardium was added to the choices of graft materials used to expand the corpora to accommodate the implant alongside the fibrous tissue. Also, the technique for open excavation of fibrous tissue through extended corporotomies was further evaluated in a series of nine cases. Downsized prostheses that were previously implanted in cases of penile fibrosis were replaced by regular-sized ones after having served as tissue expanders. Finally, minimally invasive, visually guided, sharp excavation of fibrous tissue has evolved through three stages, combining endoscopy and ultrasonography to safely excavate corporeal fibrous tissue.

Penile change following radical prostatectomy: Size, smooth muscle atrophy, and curve

Dr. Patrick Walsh's description of nerve-sparing prostatectomy was an important landmark in the surgical treatment of prostate cancer. Despite the dramatic improvement in postoperative potency rates, anecdotal reports of penile size loss were increasingly reported by patients. Experimental studies in animals revealed penile fibrosis and corporal cavernosal smooth muscle apoptosis after cavernosal nerve ablation. After an observational cross-sectional study demonstrated a time-dependent loss of penile length and circumference in men presenting with erectile dysfunction after nerve-sparing prostatectomy, several prospective studies supported the observational study. A prospective penile biopsy study before and after surgery demonstrated replacement of corporal smooth muscle with collagen and provided a possible explanation for loss of penile length. The mechanism has not yet been elucidated. This article reviews in detail the existing studies on loss of penile size after prostatectomy and possible etiologic mechanisms.

Implantation of Penile Prosthesis in Cases of Corporeal Fibrosis: Modified Shaeer's Excavation Technique

Implantation of penile prosthesis in case of corporeal fibrosis poses a greater risk of complications because of the blinded aggression involved. Penoscopic excavation and ultrasonography-guided excavation can decrease these complications but still have limitations. This work described the combination of penoscopy-guided and ultrasound-guided excavation in a trial to eliminate the limitations inherent to both. Twelve patients with penile fibrosis were operated upon. A guide wire was inserted under ultrasound monitoring, along which penoscopic corporotomy and resection was performed. Ultrasound was also used to monitor penoscopic excavation toward the tip of the corpus cavernosum and crus. Ease of the procedure, safety, extent of dilatation, and girth of prosthesis implanted. The procedure was relatively easy. Ten cases were dilated up to size 13.5 Hegar, and two up to size 14. Size 13 prosthesis was implanted in all cases. The relative safety of the procedure, the low incidence of complications, the possibility of restoring length and girth to an extent, and the resultant generous dilatation of the corpora for accommodating a sizable unhindered inflatable penile prosthesis all make ultrasound-guided penoscopic corporotomy and resection a valid option for prosthesis implantation in cases of penile fibrosis.

MR Imaging of Nonmalignant Penile Lesions

Magnetic resonance (MR) imaging is potentially useful in the assessment of many benign penile diseases. When T1- and T2-weighted sequences are used, MR imaging can clearly delineate the tunica albuginea and can be used to diagnose penile fracture and Peyronie disease; in both conditions, MR imaging may help refine the surgical approach. It is also useful in cases of priapism; in these cases, intravenously administered contrast material can help assess the viability of the corpora cavernosa and the presence of penile fibrosis. In the assessment of a penile prosthesis, MR imaging provides excellent anatomic information and is the investigation of choice. In the evaluation of erectile dysfunction, MR imaging has limited value, and for urethral stricture, it has not yet proved adequately superior to other modalities to justify its routine use.