Extracellular Matrix Changes in Urethral Stricture Disease

Pharmacotherapy of urethral stricture

Urethral stricture is characterized by the chronic formation of fibrous tissue, leading to the narrowing of the urethral lumen. Despite the availability of various endoscopic treatments, the recurrence of urethral strictures remains a common challenge. Postsurgery pharmacotherapy targeting tissue fibrosis is a promising option for reducing recurrence rates. Although drugs cannot replace surgery, they can be used as adjuvant therapies to improve outcomes. In this regard, many drugs have been proposed based on the mechanisms underlying the pathophysiology of urethral stricture. Ongoing studies have obtained substantial progress in treating urethral strictures, highlighting the potential for improved drug effectiveness through appropriate clinical delivery methods. Therefore, this review summarizes the latest researches on the mechanisms related to the pathophysiology of urethral stricture and the drugs to provide a theoretical basis and new insights for the effective use and future advancements in drug therapy for urethral stricture.

Extracellular matrix analysis of fibrosis: A step towards tissue engineering for urethral stricture disease

The urogenital tract is a target for many congenital and acquired diseases, both benign and oncogenic. In males, the urethra that transports urine and semen can be obstructed by a fibrotic disease called urethral stricture disease (USD). In severe USD, the whole organ including the vascular embedding, the corpus spongiosum (CS), is affected. Recurrent or severe USD is treated by reconstructive surgery. Tissue engineering may improve the outcome of urethral reconstruction in patients with complicated USD. Currently in urethral reconstruction only the epithelial layer is replaced, no substitution for the CS is provided, while the CS is important for mechanical support and vascularization. To develop a tissue engineering strategy for the CS, it is necessary to know the protein composition of the CS. As the extracellular matrix (ECM) plays an important role in the formation of fibrosis, we analyzed the distribution and localization of ECM components in human healthy and fibrotic CS tissue using immunohistology. The morphology of components of the elastic network were affected in USD. After decellularization a clear enrichment of proteins belonging to the ECM was found. In the proteomic analysis collagens COL15A1 and COL4A2 as well as inter-alpha-trypsin inhibitor ITIH4 were upregulated in fibrotic samples. The glycoproteins Periostin (POSTN), Microfibrillar-associated protein 5 (MFAP5) and EMILIN2 are downregulated in fibrotic tissue. To our knowledge this is the first proteomic study of ECM proteins of the CS in healthy and in USD. With these results a regenerating approach for tissue engineered CS can be developed, including relevant ECM proteins that reduce fibrosis and promote healthy healing in urethral reconstructive surgery.

Complications after Prostate Cancer Treatment: Pathophysiology and Repair of Post-Radiation Urethral Stricture Disease

Radiation therapy (RT) in the management of pelvic cancers remains a clinical challenge to urologists given the sequelae of urethral stricture disease secondary to fibrosis and vascular insults. The objective of this review is to understand the physiology of radiation-induced stricture disease and to educate urologists in clinical practice regarding future prospective options clinicians have to deal with this condition. The management of post-radiation urethral stricture consists of conservative, endoscopic, and primary reconstructive options. Endoscopic approaches remain an option, but with limited long-term success. Despite concerns with graft take, reconstructive options such as urethroplasties in this population with buccal grafts have shown long-term success rates ranging from 70 to 100%. Robotic reconstruction is augmenting previous options with faster recovery times. Radiation-induced stricture disease is challenging with multiple interventions available, but with successful outcomes demonstrated in various cohorts including urethroplasties with buccal grafts and robotic reconstruction.

Collagen is More Abundant and Structurally Altered in Lichen Sclerosus

OBJECTIVE

To test the hypothesis that genital skin and male urethra affected by lichen sclerosus (LS) has increased collagen content and altered collagen structure.

METHODS

We used picrosirius red to stain and image collagen in human urethral, vulvar, and foreskin specimens with and without LS. Using Image J software, we quantified and compared (1) collagen content (using 2o metrics: collagen proportionate area [CPA] and collagen fiber count), (2) collagen fiber length and width, and (3) collagen structure using the texture analysis technique gray level co-localization matrix (GLCM) with respect to LS status and tissue type.

RESULTS

We analyzed 23 LS specimens (vulva n=9, urethra n=7, foreskin n=7) and 29 non-LS specimens (vulva n=9, urethra n=7, foreskin n=13). Fiber count and CPA were significantly higher in all LS specimens compared to non-LS specimens (CPA: mean±SD 0.971±0.03 vs 0.948±0.02, P < .007; fiber count: mean±SD = 2906±127 vs 2509±78 fibers; P = .003). Collagen fiber width and length were similar with respect to LS status. GLCM analysis showed decreased inverse difference moment and increased entropy in LS tissues indicative of less homogeneous and more disorganized tissue structure (P<.001).

CONCLUSION

LS tissues have greater collagen content compared to non-LS tissues. Quantitative assessment of collagen organization, using GLCM, revealed less homogeneity and more disorganization of collagen in LS compared to non-LS tissues. Taken together, our findings suggest that alterations in physical tissue properties seen in LS may be due to both increased collagen abundance and altered structure.

The Role of LIM Kinase in the Male Urogenital System

The LIM kinases (LIMK1 and LIMK2), known as downstream effectors, and the Rho-associated protein kinase (ROCK), a regulator of actin dynamics, have effects on a diverse set of cellular functions. The LIM kinases are involved in the function of the male urogenital system by smooth muscle contraction via phosphorylation of cofilin and subsequent actin cytoskeleton reorganization. Although LIMK1 and LIMK2 share sequence similarities as serine protein kinases, different tissue distribution patterns and distinct localization during cell cycle progression suggest other biological functions for each kinase. During meiosis and mitosis, the LIMK1/2–cofilin signaling facilitates the orchestrated chromatin remodeling between gametogenesis and the actin cytoskeleton. A splicing variant of the LIMK2 transcript was expressed only in the testis. Moreover, positive signals with LIMK2-specific antibodies were detected mainly in the nucleus of the differentiated stages of germ cells, such as spermatocytes and early round spermatids. LIMK2 plays a vital role in proper spermatogenesis, such as meiotic processes of spermatogenesis after puberty. On the other hand, the literature evidence revealed that a reduction in LIMK1 expression enhanced the inhibitory effects of a ROCK inhibitor on the smooth muscle contraction of the human prostate. LIMK1 may have a role in urethral obstruction and bladder outlet obstruction in men with benign prostatic hyperplasia. Moreover, LIMK1 expression was reduced in urethral stricture. The reduced LIMK1 expression caused the impaired proliferation and migration of urethral fibroblasts. In addition, the activated LIMK2–cofilin pathway contributes to cavernosal fibrosis after cavernosal nerve injury. Recent evidence demonstrated that short-term inhibition of LIMK2 from the immediate post-injury period prevented cavernosal fibrosis and improved erectile function in a rat model of cavernosal nerve injury. Furthermore, chronic inhibition of the LIMK2–cofilin pathway significantly restrained the cavernosal veno-occlusive dysfunction, the primary pathophysiologic mechanism of post-prostatectomy erectile dysfunction through suppressing fibrosis in the corpus cavernosum. In conclusion, the LIM kinases–cofilin pathway appears to play a role in the function of the male urogenital system through actin cytoskeleton reorganization and contributes to the pathogenesis of several urogenital diseases. Therefore, LIM kinases may be a potential treatment target in urogenital disorder.

Scar-modulating agents post urethroplasty: Could phosphodiesterase-5 inhibitors be the answer?

Background:

Phosphodiesterase enzyme inhibitors (PDEIs) are most commonly prescribed by urologists for the treatment of erectile dysfunction. They are also gaining popularity as a treatment for lower urinary tract symptoms, based on their effect on smooth muscles – either vascular smooth muscles or smooth muscles in the urinary tract. For vascular smooth muscles, they cause vasodilation, enhanced microcirculatory haemodynamics through inhibition of platelet aggregation and adhesion, induction of apoptosis of adhesion fibroblasts and a reduction in the scarring process.

Methodology:

We reviewed articles published in English and indexed in the PubMed, Embase and Google Scholar databases, and consulted textbooks. Key search terms used were: urethral stricture, anti-fibrotic, scar-modulating agent, PDEIs, urethral scarring and urethroplasty. We created a synopsis of relevant articles, including original research studies and reviews. Level of evidence: Not applicable.

Evaluation of oxidative stress in bladder in urethral injuries: an experimental model in rats

Background: The aim of this study is to determine the changes of some oxidative stress parameters following an experimental urethral injury.

Materials and Methods: 24 Wistar-Albino male rats were used and 18 of them were exposed to urethral injury. Total oxidant status (TOS) and total antioxidant capacity (TAC) values in bladder and penile tissues and sera of rats during creation and healing stages of injury (control, day-1, 7 and 21) were examined and evaluated histopathologically.

Results: TOS levels in both tissue and serum groups increased nearly 4x fold in first day following injury. On the seventh day, TOS levels of bladder and penile tissue showed a nearly 50% decrease according to first day (p=0.005; p=0.025, respectively). At the end of third week, while bladder TOS levels decreased to control values, penile tissue TOS levels remained at high levels. The bladder TAC values mildly increased in first day (p=0.026) and then returned to normal levels in seventh day and continued to decrease down by half of control levels at the end of third week (p=0.005). TAC levels of penile tissue increased twofold in first day (p=0.021) and remained at same high levels for three weeks.

Conclusion: We observed that first day after traumatic urethral injury seems to be very important for evaluation of traumatic injuries and wound healing. We believe when an urethral injury was occured, both urethra and bladder should be handled with care and without delay during urethral healing, because of the presence of oxidative changes in bladder.

Investigation of interaction phenomena between lower urinary tract and artificial urinary sphincter in consideration of urethral tissues degeneration

Lower urinary tract dysfunction pertains to symptoms related to the lower urinary tract (LUT), with consequent incontinence. Artificial urinary sphincters (AUS) are adopted to obtain continence conditions, mainly in male subjects, via urethral occlusion by applying pressure load, mostly operating on the basis of an empirical approach. Considering the frequent access of elderly patients to this surgical practice, tissue degradation related to aging phenomena must be investigated. Computational models of the LUT structures and the AUS systems have been designed to evaluate tissues mechanical stimulation and degenerative phenomena for reciprocal interaction. Virtual solid models of the LUT have been developed starting from biomedical images, as histological/morphometrical data. Segmentation procedures have been exploited to provide the three-dimensional reconstruction, and subsequent discretization techniques led to the finite element model. Contemporarily, a finite element model of a typical AUS device was developed. Numerical analyses have been performed to analyze interaction phenomena between AUS and LUT. Different conditions were investigated, modifying both loading conditions, as intraluminal pressure and AUS action, and urethral tissues properties. Particular attention was devoted to tissues parameters, aiming to evaluate the influence of tissues degeneration because of aging and/or pathologies.

Longitudinal muscular column in the prostatic urethral wall: Its form, shape, and possible function based on mathematical simulation in ejaculation

BACKGROUND

The shape and function of the longitudinal muscular column (LMC) of the prostate have not been established in detail. The present study was undertaken to elucidate the roles of the LMC of the posterior wall of the prostatic urethra (PSU) in the emission phase of ejaculation by investigating the form and muscular arrangement of the LMC.

METHODS

Prostates and urinary bladders were obtained from 14 Korean adult cadavers. Nine specimens were histologically analyzed using hematoxylin and eosin, Masson's trichrome, and Verhoeff-van Gieson staining. Two specimens were scanned using microcomputed tomography (micro-CT), and all scanned images were reconstructed into a three-dimensional model.

RESULTS

At the proximal level of the prostate, the ejaculatory ducts (EDs) and prostatic utricle (PU) together were surrounded by circular smooth-muscle fibers. However, at the seminal colliculus (SC) where the EDs and PU opened, they were mainly surrounded by an abundance of longitudinal fibers. The longitudinal fibers posterior to the EDs and PU formed a distinctive LMC in the posterior urethral wall. In histologic sections and micro-CT images, the LMC extended distally from the level of the SC to the level of the membranous urethra (MBU). We simulated a potential mechanism of LMC using a mathematical model of its movements.

CONCLUSIONS

Comprehensive analyses based on in-depth assessment of histologic characteristics and micro-CT images demonstrated extension of the LMC from the level of the SC to the level of the MBU, enabling a better understanding of ejaculation physiology involving the LMC. These results suggest that the LMC in the posterior wall of the PSU is a critical component of ejaculation by facilitating the ejection of seminal vesicle fluid into the PSU via well-coordinated contractions.

Histopathologic Evaluation of the Effects of Intraurethral Platelet Rich Plasma in Urethral Trauma Experimentally Induced in Rat Model

OBJECTIVE

To determine the efficacy of platelet rich plasma applied early initialization after urethral trauma for preventing inflammation and spongiofibrosis.

MATERIALS AND METHODS

Twenty-three rats were randomized and divided into 3 groups, with 10 rats in 2 groups. Only sham group had 3 rats. The urethras of all rats were traumatized with a pediatric urethrotome knife at 6- and 12-o'clock. For 15 days, group I was given platelet rich plasma (PRP) once a day without urethral injury (sham group), group II (n = 10) was not given any medical treatment only urethral injury group (UI-PRP), group III (n = 10) was given PRP once a day intraurethrally as instillation using a 22 ga catheter sheath with urethral injury (UI+PRP). On day 15, the penises of the rats were degloved to perform penectomy.

RESULTS

A significant difference was detected in all parameters when the sham, UI-PRP, UI+PRP groups were compared (respectively, P = .001, / <.001, / .008 / .007) and a significant difference was observed among mucosal inflammation, fibrosis, and edema parameters when UI-PRP and UI+PRP groups were compared. (Respectively; P <.001, / <.001 / .006).

CONCLUSION

In this study, it was shown that intraurethral PRP applied after urethral trauma significantly decreased mucosal inflammation, spongiofibrosis, and edema. Depending on the results we acquired in this study, we think that PRP may be a promising option in urethral stricture treatment.

Structural Analysis of the Bulbospongiosus Muscle in Patients With Bulbar Urethral Strictures

OBJECTIVE

To characterize the bulbospongiosus muscle (BSM) in patients with bulbar urethral strictures.

MATERIALS AND METHODS

We studied 21 patients divided into 2 groups: Stricture Group (n = 14; mean age = 62.00 years) with bulbar stricture submitted to open urethroplasty; and Control Group (n = 7; mean age = 60.14 years) with penile strictures (hypospadias cripples, penile cancer and/or penile infection) who were submitted to perineal urethrostomy. Samples of the BSM were dissected and histologic sections were stained by histochemical and immunohistochemical techniques. Histomorphometric analyzes were performed on photomicrographs. Means were statistically compared using the unpaired Student t test and the Mann-Whitney test (P <.05).

RESULTS

The etiology of bulbar urethral stricture was idiopathic in 2 cases (14.29%), post-TURP in 6 (42.86%), post open radical prostatectomy in 5 (35.71%) and post open prostatectomy in 1 case (7.14%). The average length of the stricture was 2.08 cm. The only parameter analyzed with significant difference between the groups was the vessels (significant difference between the control group: 5.11 ± 1.98% and stricture group: 3.57 ± 1.32%, P = .0460). The quantitative analysis of collagen (Control Group: 10.63 ± 5.37% and Stricture Group: 10.83 ± 4.55%, P = .9296); diameter of BSM muscle fibers (Control Group: 41.71 ± 14.63 µm and Stricture Group: 40.11 ± 8.59 µm, P = .76 and elastic system fibers (Control Group; 3.83 ± 1.54% and Stricture Group: 5.43 ± 2.90%, P = .2601) showed no significant difference.

CONCLUSIONS

Histologic analysis showed a significant decrease of the BSM vessels in urethral stricture, without changes in elastic fibers, collagen, nerves, and muscle fiber diameter. These findings show that the bulbar urethral stricture causes minimal alterations in the structure of the BSM.

An Experimental Model of Anterior Urethral Stricture in Rabbits With Local Injections of Bleomycin

OBJECTIVE

To develop an experimental model of anterior urethral stricture in rabbits using a bleomycin (BLM) injection technique.

MATERIALS AND METHODS

Thirty adult male New Zealand rabbits were randomly divided into 4 groups. In group 1 (BLM group), BLM was injected into the urethral submucosal tissue every other day through a catheter for 6 weeks at the 3-, 6-, 9-, and 12-o'clock positions of the urethra in 12 rabbits. In group 2 (phosphate-buffered saline [PBS] group), PBS was injected instead of BLM in 6 rabbits. In group 3 (stricture control group), an 8 × 20 mm urethral defect was created in 6 rabbits. In group 4 (normal group), 6 normal rabbits were included. All rabbits in the PBS group and stricture control group, as well as 6 rabbits in the BLM group, were sacrificed at 6 weeks. The remaining 6 rabbits in the BLM group were sacrificed at 10 weeks. Urethrography was performed in all rabbits before sacrifice, and the urethra was harvested for histologic analysis.

RESULTS

All rabbits in the BLM group showed mild urethral stricture at 4 weeks and significant urethral stricture at 6 weeks, without spontaneous resolution of the stricture at 10 weeks. No urethral stricture was observed in the PBS group at 4 and 6 weeks. Histologic examination confirmed the presence of fibrosis in the BLM group without spontaneous improvement.

CONCLUSION

BLM injection can induce an experimental model of anterior urethral stricture in rabbits. This simple, highly efficient, reproducible method can be carried out in any laboratory.

Overcoming scarring in the urethra: Challenges for tissue engineering

Urethral stricture disease is increasingly common occurring in about 1% of males over the age of 55. The stricture tissue is rich in myofibroblasts and multi-nucleated giant cells which are thought to be related to stricture formation and collagen synthesis. An increase in collagen is associated with the loss of the normal vasculature of the normal urethra. The actual incidence differs based on worldwide populations, geography, and income. The stricture aetiology, location, length and patient's age and comorbidity are important in deciding the course of treatment. In this review we aim to summarise the existing knowledge of the aetiology of urethral strictures, review current treatment regimens, and present the challenges of using tissue-engineered buccal mucosa (TEBM) to repair scarring of the urethra. In asking this question we are also mindful that recurrent fibrosis occurs in other tissues-how can we learn from these other pathologies?

Urethral lumen occlusion by artificial sphincteric device: Evaluation of degraded tissues effects

Urinary incontinence can be surgically treated by means of artificial sphincters, based on a cuff that provides a pressure around the urethra to occlude the lumen. Considering the frequent access of elderly patients to this surgical practice, tissue degradation phenomena must be investigated, since they could affect treatment reliability and durability. The potential degradation can be interpreted considering a variation within soft tissue constitutive formulation, by means of a correlation between mechanical properties and tissues ageing. The overall compressibility varies, as characteristics aspect of soft tissue mechanical response with age, as well as the stiffness. The investigation is performed by means of a three dimensional numerical model of the urethral duct. The effects of the interaction phenomenon with a cuff is interpreted considering the changes, within the constitutive models, of the basic parameters that define the potential degradation process. The deformation related to compressibility is recalled, ranging between ten and fifty percent in dependence on the degradation level considered. This parameter, reported mostly as representative of the aging effect, shows a large variation that confirms the relevance of the investigation performed toward a sensitivity of the mechanical response of the urethral duct referred to the lumen occlusion.

The effect of rapamycin on TGFβ1 and MMP1 expression in a rabbit model of urethral stricture

PURPOSE

To investigate the effect of rapamycin on TGFβ1 and MMP1 expression in a rabbit model of urethral stricture.

METHODS

Twenty-four adult New Zealand male rabbits underwent an electrocoagulation of the bulbar urethra with a 13Fr pediatric resectoscope. Then rabbits were randomly divided into three groups: (1) normal control group: normal saline (NS), (2) the vehicle control group: dimethyl sulfoxide (DMSO), and (3) the treatment group: effective-dose rapamycin in DMSO (Ra), with 12, 6, and 6 rabbits in each group, respectively. Drugs were given by urethral irrigation daily for 4 weeks. Urethral tissue was harvested for histological and molecular analyses. TGFβ1 and MMP1 expression levels were evaluated by real-time quantitative PCR and immunohistochemistry.

RESULTS

Ten, six, and six rabbits were evaluated finally in Ra, DMSO, and NS group, respectively. Histological examination revealed the distribution of fibrosis and the degree of collagen deposition in the Ra group were smaller and slighter than the two control groups. Collagen content was significantly less in the Ra group than in the DMSO group (P < 0.001) and the NS group (P < 0.001). qRT-PCR analysis showed a higher expression of MMP1 mRNA in the Ra group than in the DMSO group (P < 0.001) and the NS group (P < 0.001). Immunohistochemistry showed the protein levels of MMP1 in the Ra group were significantly increased when compared with the DMSO group (P < 0.01) and the NS group (P < 0.01). On the other hand, no statistical difference could be found between every two groups in both mRNA and protein levels of TGFβ1.

CONCLUSIONS

Rapamycin enhances the expression of MMP1 in a rabbit model of urethral stricture, but has no direct effect on the expression of TGFβ1.

Histopathological characteristics of buccal mucosa transplants in humans after engraftment to the urethra: a prospective study

PURPOSE

Histopathological changes in buccal mucosa transplants after engraftment to the urethra and exposure to urine remain nebulous. We investigated histopathological changes in buccal mucosa transplants integrated into the urethra in humans.

MATERIALS AND METHODS

We prospectively evaluated 22 patients with recurrent urethral stricture after buccal mucosa urethroplasty between November 2012 and October 2013. All patients underwent repeat buccal mucosa urethroplasty performed by a single surgeon. Intraoperatively we harvested a sample of the integrated buccal mucosa transplant previously engrafted to the urethra, a sample of healthy urethra, a sample of freshly harvested buccal mucosa from the contralateral inner cheek and a sample of fibrotic tissue from the area of the current stricture. A dedicated uropathologist performed meticulous histopathological examination of all tissue samples using hematoxylin and eosin staining. Preoperative clinical data were also collected on all patients.

RESULTS

The mean interval from previous to current buccal mucosa urethroplasty was 22.2 months (range 4.1 to 76.0). Mean stricture length at repeat urethroplasty was 52.7 mm (range 30.0 to 70.0). Histopathological characteristics of the integrated buccal mucosa transplants were completely preserved in all patients, consisting of thick sheets of stratified nonkeratinized squamous epithelium with a stratum spinosum. Transplants were not partially or entirely overgrown with urothelium.

CONCLUSIONS

Buccal mucosa transplants retain their histopathological characteristics and are not overgrown with urothelium after urethral engraftment and urine exposure in humans. These findings may explain the superiority of buccal mucosa transplants on the outcome of substitution urethroplasty compared to that of other materials.

Prevention of stricture recurrence following urethral endoscopic management: what do we have?

OBJECTIVE

Strictures of the urethra are the most common cause of obstructed micturition in younger men and there is frequent recurrence after initial treatment. This review was performed to determine the best strategy for stricture recurrence prevention following urethral endoscopic management.

METHODS

We reviewed the published literature in PubMed, the Cochrane Library, and Google Scholar focusing on this intractable problem regardless of language restrictions. Outcomes of interest included the study methods and the applied strategy's efficacy. The level of evidence and grade of recommendations of included studies were appraised with an Oxford Centre for Evidence-Based Medicine Scale.

RESULTS

Currently, numerous techniques, including catheterization, repeated dilation, brachytherapy, and intraurethral use of various antifibrosis agents, have been employed to oppose the process of wound contraction or regulate the extracellular matrix. But unfortunately, none of these techniques or agents have demonstrated efficacy with enough evidence.

CONCLUSIONS

Although lots of strategies are available, still, we do not have a suitable, single optimum solution for all the conditions. The clinical decision of stricture-recurrence-prevention techniques should be carefully tailored to every individual patient. As the studies are not sufficient, more efforts are warranted to address this interesting but challenging issue.

Effects of hyaluronic acid and carboxymethylcellulose on urethral stricture after transurethral resections of the prostate for benign prostatic hyperplasia: a multicenter, single blinded, randomized controlled study

PURPOSE

To evaluate the effect of hyaluronic acid (HA) and carboxymethylcellulose (CMC) instillation after transurethral resection of the prostate (TURP) on preventing urethral stricture.

PATIENTS AND METHODS

A total of 180 patients underwent TURP for benign prostatic hyperplasia. Recruited patients were randomly divided into two groups: Groups A and B. Patients in group A (90 patients, experimental group) received HA/CMC instillation, and patients in the group B (90 patients, control group) received lubricant instillation after TURP. Each patient was evaluated at 4 weeks (V1), 12 weeks (V2), and 24 weeks (V3) after the surgery. The effectiveness of HA/CMC instillation was evaluated based on the International Prostate Symptom Score/Quality of Life, peak urine flow rate, voided volume, and postvoid residual volume. The visual analogue scale (VAS) pain score and degree of satisfaction were also determined for each participant.

RESULTS

Among 180 initial participants, 80 patients in group A and 81 patients in group B had completed the experiment. VAS pain scores were 0.75±0.75 and 1.75±1.37 (P<0.001), and degrees of satisfaction were 0.63±0.66 and 0.91±0.51 in group A and group B at 1 month after surgery (P=0.002). By retrograde urethrography, urethral stricture after TURP was seen in 1 of 80 subjects in group A and 7 of 81 subjects in group B.

CONCLUSIONS

HA/CMC instillation after TURP decreased the incidence of urethral stricture. In addition, HA/CMC was effective at reducing pain during the early postoperative period, with no adverse effects.

Stereological and biochemical analysis of the urethral edges in patients submitted to end-to-end anastomosis for bulbar urethral stricture

PURPOSE

To study the morphologic alterations in the proximal and distal urethral edges from patients submitted to end-to-end bulbar urethroplasty.

MATERIALS AND METHODS

We analyzed 12 patients submitted to anastomotic urethroplasty to treat bulbar strictures less than 2.0 cm in length. After excision of the fibrotic segment to a 28Fr urethral caliber, we obtained biopsies from the spongious tissue of the free edges (proximal: PROX and distal: DIST). Controls included normal bulbar urethras obtained from autopsies of 10 age matched individuals. The samples were histologically processed for smooth muscle cells (SMC), elastic system fibers and collagen. Stereological analysis was performed to determine the volumetric density (Vv) of each element. Also, a biochemical analysis was performed to quantify the total collagen content.

RESULTS

Vv of SMC was reduced in PROX (31.48 ± 7.01 p < 0.05) and similar in DIST when compared to controls (55.65 ± 9.60%) with no statistical difference. Elastic fibers were increased in PROX (25.70 ± 3.21%; p < 0.05) and were similar to controls in DIST (15.87 ± 4.26%). Total collagen concentration in PROX (46.39 ± 8.20 µg/mg), and DIST (47.96 ± 9.42 µg/mg) did not differ from controls (48.85 ± 6.91 µg/mg). Type III collagen was similarly present in all samples.

CONCLUSIONS

After excision of the stenotic segment to a caliber of 28Fr, the exposed and macroscopically normal urethral edges may present altered amounts of elastic fibers and SMC, but are free from fibrotic tissue. When excising the peri-stenotic tissue, the surgeon should be more careful in the proximal end, which is the most altered.

Efficacy of holmium laser urethrotomy in combination with intralesional triamcinolone in the treatment of anterior urethral stricture

Purpose

To evaluate the outcome of visual internal urethrotomy with a holmium:yttrium-aluminum-garnet laser along with intralesional triamcinolone injection.

Materials and Methods

Patients with an anterior urethral stricture less than 3 cm in length were evaluated by clinical history, physical examination, uroflowmetry, and retrograde urethrogram preoperatively. All patients were treated with holmium laser urethrotomy and intralesional triamcinolone (80 mg) injection under general or regional anesthesia. An 18 F urethral catheter was placed for 5 days. All patients were followed up for 12 months postoperatively by history, uroflowmetry, and if required, retrograde urethrogram or urethroscopy every 3 months.

Results

The mean age of the patients was 42.9 years (range, 14 to 70 years). The overall recurrence rate was 24%. The success rate in patients with strictures less than 1 cm in length was 95.8%, whereas that in patients with strictures of 1 to 3 cm in length was 57.7% (p=0.002). The outcome did not depend on age, duration of symptoms, etiology, or location of stricture.

Conclusions

Holmium laser urethrotomy with intralesional triamcinolone is a safe and effective minimally invasive therapeutic modality for urethral strictures. This procedure has an encouraging success rate, especially in those with stricture segments of less than 1 cm in length.

Pathology of urethral fibromuscular system related to parturition-induced stress urinary incontinence and TGF-β1/Smad pathway

To study pathological changes of fibromuscular system and the role of TGF-β1/Smad pathway in the urethra of a parturition-induced stress urinary incontinence (SUI) rat model. Twenty-eight 8-week-old Sprague-Dawley female rats at gestational day 16 were used and randomized into two groups: sham group and SUI group. After delivery, rats in the SUI group underwent postpartum vaginal balloon dilation and bilateral ovariectomy. 1 month after ovariectomy, urodynamics was assessed. Histological examination (Masson's trichrome stain, picrosirius red stain, Hart's elastin stain, Gordon & Sweet's stain, and immunohistochemical stain) and Western blot were performed on urethral tissues. Both leak point pressure and maximal bladder capacity were significantly decreased in the balloon-injured ovariectomized rats, compared with the sham rats. Muscle was significantly decreased in the urethra of SUI rats compare with sham rats. Collagen I/III and reticular fibers from SUI group were also significantly lower than sham group. Meanwhile, elastic fibers and reticular fibers showed fragmentation and disorganization indicating impairment in the fibromuscular system in SUI rats. TGF-β1, MMP-9, and phosphorylated Smad2 (p-Smad2) were expressed significantly higher in SUI than in sham rats. Simulated birth trauma and menopause induced an upregulation of the TGF-β1/Smad pathway and impairment of the fibromuscular system in the urethra.

Human acellular matrix graft of tunica albuginea for penile reconstruction

INTRODUCTION

Penile curvature is one of the most common male conditions, affecting nearly 10% of men, and can impair sexual intercourse. Tunica albuginea (hTA) plays a key role in penile curvature, and reconstructive procedures may be necessary for its substitution. Although several grafts have been proposed for hTA repair, the ideal graft is not yet available.

AIM

The aim of this article is to evaluate a new human tunica albuginea acellular matrix (hTAAM) as potential graft for penile reconstructive procedures.

METHODS

Twelve penises were obtained during sex reassignment surgeries from male-to-female transsexual patients. After dissection, hTAs were assigned into two groups according to the decellularization methods: polyethylene glycol (PEG) 1000 method following ultraviolet-C radiation, and Triton X-100 modified method.

MAIN OUTCOME MEASURES

Structural analyses were assessed by hematoxilin and eosin, Masson's trichrome, Weigert's, and picrosirius-polarization staining methods. Total protein, total glycosaminoglycan (GAG), and nucleic acid (DNA and RNA) concentrations were assessed by specific biochemical analyses. Uniaxial strength tests were performed to evaluate biomechanical properties.

RESULTS

All hTAAMs presented no nuclear or cellular remnants. Total protein concentration was significantly higher in PEG 1000 hTAAM. Despite GAG concentration decreased significantly in hTAAM, Triton X-100 hTAAM retained the highest GAG concentration (1.0 ± 0.42 µg HexUr/mg dry tissue, P > 0.05). All decellularization methods were efficacious to remove nucleic acids. The maximal break point presented no difference between hTA and hTAAM groups (P > 0.05).

CONCLUSIONS

PEG 1000 and Triton X-100 decellularization methods provide equally successful hTAAMs, preserving original structural and biochemical properties.

Effect of the gonadal status and the gender on glycosaminoglycans profile in the lower urinary tract of dogs

Glycosaminoglycans (GAGs) form a functional component of connective tissues that affect the structural and functional integrity of the lower urinary tract (LUT). The specific GAGs of physiological relevance are both nonsulfated (hyaluronan) and sulfated GAGs (chondroitin sulphate [CS], dermatan sulphate [DS], keratan sulphate [KS], and heparan sulphate [HS]). As GAG composition in the LUT is hormonally regulated, we postulated that gonadectomy-induced endocrine imbalance alters the profile of GAGs in the canine LUT. Four regions of the LUT (body and neck of the bladder as well as the proximal and distal urethra) from 20 clinically healthy dogs (5 intact males, 5 intact anoestrus females, 4 castrated males, and 6 spayed females) were collected, wax-embedded and sectioned. Alcian blue staining at critical electrolyte concentrations was performed on the sections to determine total GAGs, hyaluronan, total sulfated GAGs, combined components of CS and DS, as well as KS and HS. The amount of staining was evaluated in 3 tissue layers, i.e., epithelium, subepithelial stroma and muscle within a region. Overall, hyaluronan (67.1%) was the predominant GAG in the LUT. Among sulfated GAGs, a combined component of KS and HS was found to be 61.8% and 38.2% for CS and DS. Gonadal status significantly affected GAG profiles in the LUT (P < 0.01). All GAG components were lower (P < 0.05) in body of the bladder of gonadectomized dogs. Total sulfated GAGs and a combined component of KS and HS were lower (P < 0.05) in all 4 regions of gonadectomized dogs. Except for a combined component of CS and DS, decreases in all GAGs were found more consistently in the muscle compared to other tissue layers. Differences between genders became obvious only when considered along with the effect of gonadal status. In gonadectomized dogs, changes in GAG components in the LUT were more consistent in females compared to males; this may partly explain different levels of risk in the development of urinary incontinence between genders. Quantitative differences in GAG profiles found between intact and gonadectomized dogs indicate a potential role of gonadectomy-induced endocrine imbalance in modifying GAG composition in the canine LUT. Profound alteration in the pattern of GAGs in gonadectomized dogs may compromise structural and functional integrity of the LUT and is possibly involved in the underlying mechanism of urinary incontinence post neutering.

Early experience with hyaluronic Acid instillation to assist with visual internal urethrotomy for urethral stricture

Purpose

The clinical usefulness of hyaluronic acid (HA) instillation during visual internal urethrotomy (VIU) for decreasing the incidence of recurrent urethral stricture was assessed.

Materials and Methods

Twenty-eight patients were treated by VIU with HA instillation between May 2007 and June 2009. After insertion of a Foley catheter following urethrotomy, HA was instilled via an 18-gauge tube catheter between the urethral lumen and Foley catheter. Seventeen cases were analyzed retrospectively 12 months postoperatively. We evaluated the success rate of this procedure by comparing retrograde urethrography (RGU) results, maximum flow rates, and postvoid residual urine volumes preoperatively and 3 and 12 months postoperatively. Success was defined as either a maximum flow rate of at least 15 ml/s or no visible urethral stricture on RGU at 12 months postoperatively.

Results

Total success rates were 76.5% (13/17) and 52.9% (9/17) at 3 and 12 months postoperatively, respectively. By etiology, success rates at 3 and 12 months postoperatively, respectively, were 66.7% and 33.3% for inflammation, 66.7% and 50.0% for trauma, and 83.3% and 66.7% for unknown causes. Success rates were 63.6% for strictures less than 10 mm in length and 33.3% for strictures of 10 mm or more in length at 12 months postoperatively. Success rates were 61.5% for single strictures and 25% for multiple strictures at 12 months postoperatively.

Conclusions

The success rate of VIU with HA instillation was not better than that observed in the literature for conventional VIU.

Botulinum toxin-A to improve urethral wound healing: an experimental study in a rat model

OBJECTIVES

Tensile distracting forces caused by elements such as a muscle pull can cause widening of scars in the tissue during the wound healing process. The aim of the present study was to investigate whether induced immobilization of the urethral muscle using botulinum toxin-A (BTX-A) enhances wound healing and also reduces the amount of scar formation in an experimentally induced urethral injury in a male rat model.

METHODS

Prepubertal male albino rats were divided into 2 groups: 20 rats in the BTX-A group received BTX-A injection treatment during surgery and 10 rats in the control group received 0.9% saline solution injection. The penile skin was incised circumferentially and degloved. To make the urethral injury at a location approximately 15 mm proximal to the external meatus, the urethra was cut transversally with scissors, from the 2-o'clock to the 10-o'clock position and then sutured by a single suture at the 6-o'clock position. To evaluate chronic inflammation and fibrosis, the rats were killed, and the injured portions of the urethras were harvested for histopathologic examination after a follow-up period of 21 days.

RESULTS

On histopathologic evaluation, the control group rats had a more severe fibrotic change in the urethral tissue compared with the BTX-A injected rats, which showed a mild fibrotic change. The mean +/- SD and median fibrosis score was 2.4 +/- 0.5 and 2 in the control group and 1.5 +/- 0.5 and 1 in the BTX-A group, respectively (P < .01 and P < .01, respectively).

CONCLUSIONS

The results of our study have shown that BTX-A prevented increases in collagen content during urethral wound healing.

A morphometric analysis of bulbar urethral strictures

In a beautifully descriptive paper, authors from Rio de Janeiro and San Francisco report a quantitative and qualitative histological analysis of spongiosal tissue in patients with bulbar urethral strictures. They found that stricture formation was characterised by major alterations in extracellular matrix features.

OBJECTIVE

To report a quantitative and qualitative histological analysis of spongiosum tissue in patients with bulbar urethral strictures.

MATERIALS AND METHODS

Urethral specimens from 15 patients who had end-to-end anastomotic urethroplasty were evaluated; the control group comprised five bulbar urethras from cadavers. The collagen content, elastic fibres, smooth muscle and vessels were analysed using stereological methods.

RESULTS

There was complete loss of the relationship between smooth muscle, extracellular matrix and sinusoids in the peri-luminal area (PLA), with collagen replacement. The extension of the fibrotic area was greater in those with a traumatic than in those with an atraumatic stricture. The content of smooth muscle and collagen in the peripheral spongiosum (PS) area was similar for the stricture and control groups, and results were comparable for traumatic and atraumatic groups and those with suprapubic cystostomy diversion or not before surgery. There was a remarkably lower vascular density in the traumatic than in the atraumatic group. There was an increase in type III collagen in the PLA and in type I collagen in the PS; collagen type III in the PLA was greater in the group with no suprapubic cystostomy diversion before surgery. There were fewer elastic fibres in both stricture areas (PLA and PS) than in the control group.

CONCLUSIONS

Urethral stricture formation is characterized by marked changes in extracellular matrix features, with consequent changes in organ function.

Assessment of the efficacy of absorbable adhesion barriers on dissection in esophagus operations

OBJECTIVE

During childhood, recent repeated operations for esophagus are normally conducted if long gap esophageal atresia exists. During multistaged extrathoracic esophageal elongation procedure, the dissection of the esophagus poses severe problems due to adhesion. However, Gore-Tex membrane may simplify esophagus dissection. The most popular adhesion barriers used today are sodium hyaluronate (Seprafilm; Genzyme Corp., Cambridge, MA) and oxidized regenerated cellulose (Interceed; Johnson&Johnson Medical Inc., New Brunswick, NJ). The purpose of this study is to investigate the efficacy of adhesion barriers on esophagus dissection.

METHODS

In the study, 21 Wistar albino adult male rats were worked on. The rats were randomly divided into three groups, each including seven rats. About 1cm-segment of the esophagus, located just behind the trachea, was dissected from the surrounding tissues through blunt dissection. Rats in group 1 were wrapped with Seprafilm, and in group 2 with Interceed. But the rats in group 3 underwent only esophagus dissection. Three weeks later, during esophagus dissection, adhesion scoring was performed and esophagus was divided into two parts: one for the assessment of hydroxyproline level, and the other for histological examination.

RESULTS

When the adhesion scores of the three groups were compared, there was not a significant difference between the groups (p=0.75). In terms of tissue hydroxyproline levels, mean scores of hydroxyproline revealed no significant difference between the three groups (p=0.19). When the histopathological results were examined, esophagus looked normal and no connective tissues were seen around esophagus.

CONCLUSION

Seprafilm and Interceed had no effect on esophagus dissection. Although Seprafilm had the best mean score, this was statistically insignificant. Gore-Tex might play a better role than Interceed in preventing adhesion formation; however, it is still not certain whether adhesion barrier should be used in such organs as esophagus having no serosa.

Intraurethral honey application for urethral injury: an experimental study

OBJECTIVES

To evaluate the effect of honey applied intraurethrally after urethral injury on histopathological healing.

MATERIALS AND METHODS

A total of Wistar male rats were used. The rats were divided into four groups: control (Group 1), sham (Group 2), 1 week honey applied group (Group 3) and 3 weeks honey applied group (Group 4). The urethral damage was caused with a 29 G needle. In sham group, only intraurethral saline solution was given, and 10% of honey was applied to rats in Groups 3 and 4 intraurethrally. After killing, penile tissues were investigated under a light microscopy.

RESULTS

The irregularities of urethral epithelium and connective tissue were observed in Group 1. Also narrowing of lumen was present in control group rats except one rat in which no inflammation and total healing were observed. Hyperemia-bleeding was found in whole rats. In Group 2, there were irregularities in urethral epithelium and connective tissue. Total healing was observed in one rat. In Group 3, while regularity in urethral epithelium was present in six rats, inflammation and fibrosis was absent in rats. In Group 4, inflammation and fibrous tissue accumulation were not observed in rats.

CONCLUSIONS

Intraurethral honey, applied after urethral injury, prevents inflammation, accelerates urethral healing and provides perfect healing.

The effect of indwelling catheter on OH-proline in the urethral wound: an experimental study

OBJECTIVE

To investigate the effect of catheterization on urethral wound healing by measuring OH-proline.

METHODS

Eighteen male New Zealand albino rabbits were divided equally into three groups. In the control group, urethral tissue samples were taken from the ventral penile surface. In group II, the ventral penile surface was incised and primarily repaired by 6/0 polydioxanone. In group III, the incised urethra was repaired by 6/0 polydioxanone and a urethral catheter was inserted. Tissue samples were taken on the 20th postoperative day in groups II and III. Tissue OH-proline levels were measured by the method of Bergman and Loxley. The Kruskal-Wallis statistical test was used for evaluation.

RESULTS

OH-proline values as microg/mg dry tissue were 16.43+/-2.68 in the control group, 14.47+/-1.82 in group II and 14.63+/-0.63 in group III. There was no significant difference between the three groups (P>0.05).

CONCLUSION

Use of a urethral catheter does not appear to have a direct effect on collagen synthesis in wound healing.

[Long-term results of end-to-end urethroplasty]

OBJECTIVE

We evaluated long term results of end-to-end urethroplasty.

MATERIAL AND METHODS

We reviewed 40 patients with bulbar urethral stricture of diverse origin: iatrogenic 40%, traumatic 15%, infectious 2% and unknown 40%. In 17 cases internal urethrotomy was made previously. The radiological study with retrograde and voiding cystogram revealed a bulbar location in all cases and a length inferior to 1 cm in 13 cases, between 1-2 cm in 26 cases and 2-3 cm in 1 case. The maximum flow rate varied between 3-13 ml/s. The absence of bacteriuria was valued by means of preoperating culture. The average time of pursuit was 45 months (12-142 months). The stricture was considered resolute when not appear compatible radiological or functional finds of failure.

RESULTS

In 37 cases (92%) the results were satisfactory, without secondary surgical procedure. After surgery maximum flow-rate varied between 18-45 ml/s. In two patients with failure, internal urethrotomy was decisive. In this case the stricture origin was traumatic. The third patient with failure was finally chosen to make new end-to-end urethroplasty, with good later result.

CONCLUSIONS

End-to-end urethroplasty is a highly decisive technique for bulbar urethral stricture. The preoperating diagnosis is based on the radiological study (retrograde and voiding cystogram). The postoperating control must be based on clinic and uroflow study. Traumatic stricture repair showed worse results. In cases of failure, internal urethrotomy allows to complement successful results of end-to-end urethroplasty.

COMPOSITIONAL CHANGES OF COLLAGEN AND GLYCOSAMINOGLYCANS IN THE TUNICA ALBUGINEA AND CORPUS CAVERNOSUM FROM THE HUMAN PENIS DURING THE FETAL AND POSTNATAL PERIODS

PURPOSE

We investigated the composition of collagen and glycosaminoglycans (GAGs) in the corpus cavernosum (CC) and tunica albuginea (TA) of normal human penises.

MATERIALS AND METHODS

Penises were obtained from a 6-month-old child (group 1), a 2-year-old child (group 2), 18 to 34-year-old adults (group 3), 37 to 53-year-old adults (group 4) and 22 fetuses at 17.2 to 33.3 menstrual weeks (group 5). Total GAG and collagen concentrations were expressed per mg dry tissue and proportions of GAG species were determined by agarose electrophoresis and ion exchange chromatography.

RESULTS

The GAG concentration in group 1 CC and TA was 1.32 and 0.52 microg/mg, respectively, and thereafter it increased noticeably. TA collagen concentration followed a similar pattern. TA had more collagen than CC in groups 3 (mean +/- SD 93.41 +/- 6.17 vs 53.77 +/- 11.18 microg/mg, p <0.001) and 4 (89.94 +/- 5.53 vs 55.39 +/- 5.89 microg/mg, p <0.01). In these groups TA and CC differed markedly in the proportion of hyaluronan, heparan sulfate and dermatan sulfate. In TA group 4 had slightly less hyaluronan and more chondroitin sulfate than group 3 but in CC the GAG proportions were similar. Collagen content in the whole fetal penis correlated with gestational age (r = 0.78, p <0.001).

CONCLUSIONS

Collagen and the GAG concentration in the human penis undergo extensive modifications during development and shortly after birth but from ages 2 to approximately 46 years changes are limited to the proportion of GAG species in TA from older individuals. Reflecting diverse biomechanical roles, the extracellular matrix of CC and TA are markedly different.

The concentration of elastic fibres in the male urethra during human fetal development

OBJECTIVE

To describe the distribution of elastic fibres in the developing male urethra and to provide stereological data of the concentration of elastic fibres in the human urethra.

MATERIALS AND METHODS

Urethras were obtained from 10 fresh normal human fetuses at 15-36 weeks of gestation. A place-matched spongy urethra of a 27-year-old normal adult man was also analysed. Samples were fixed in Bouin's solution, embedded in paraffin and histologically processed. The elastic system fibres were evaluated by light microscopy using Weigert's resorcin-fuchsin technique after oxidation. Morphometric values were assessed by the point-counting method. The volumetric density (Vv) of elastic fibres was correlated with fetal age.

RESULTS

At 15 weeks the elastic fibres were sparse and homogeneously distributed. The size and thickness of elastic fibres increased with age, mainly in the third trimester of gestation. Elastic fibres formed a randomly orientated network in the trabeculae of the corpus spongiosum. The mean (sem) Vv of elastic fibres in the spongy urethra was 5.2 (0.4)% in the fetus at 15 weeks and 14.8 (1.0)% at 36 weeks. In the urethra of the place- matched young man the Vv was 19.0 (1.3)%. The concentration of elastic fibres in the spongy urethra increased significantly with age.

CONCLUSION

The high concentration of elastic fibres in the spongy urethra may partly explain its high extensibility. The progressive increase in elastic fibres during development implies functional adaptation of the fetal male urethra.

The Distribution of Neuronal and Inducible Nitric Oxide Synthase in Urethral Stricture Formation

PURPOSE

The distribution of neuronal (n) and inducible (i) nitric oxide synthase (NOS) may have a role in the maintenance of normal urethral spongiosum and during the development of spongiofibrosis in urethral stricture disease.

MATERIALS AND METHODS

Eight normal and 33 strictured human bulbar urethras were studied by histological and immunohistochemical techniques for the neuronal markers S-100, nNOS and iNOS. The smooth muscle-to-collagen ratio was calculated by morphometric analysis of Masson's trichrome sections. Immunohistochemical staining patterns of the neuronal markers in normal urethral tissue was compared to that in urethral stricture tissue with spongiofibrosis.

RESULTS

The smooth muscle-to-collagen ratio was significantly lower in the strictured urethra compared to that in the control group (p = 0.001). In the strictured bulbar urethra nNOS immunoreactivity was decreased compared to that in normal urethral tissue. The severity of spongiofibrosis corresponded to the loss of nNOS immunoreactivity. iNOS immunoreactivity was found in strictured urethral epithelium and spongiosal tissue, whereas the control group was nonimmunoreactive to iNOS.

CONCLUSIONS

Urethral stricture formation is a fibrotic process associated with significant changes in NOS metabolism. Abnormal collagen synthesis following urethral trauma may be stimulated by inappropriate iNOS activity. A functional nerve supply to the urethral spongiosum seems to be crucial in the maintenance of the unique ultrastructure of the urethral spongiosum.