The Use of Halofuginone in Limiting Urethral Stricture Formation and Recurrence: An Experimental Study in Rabbits

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.

Rectifying disorder of extracellular matrix to suppress urethral stricture by protein nanofilm-controlled drug delivery from urinary catheter

Urethral stricture secondary to urethral injury, afflicting both patients and urologists, is initiated by excessive deposition of extracellular matrix in the submucosal and periurethral tissues. Although various anti-fibrotic drugs have been applied to urethral stricture by irrigation or submucosal injection, their clinical feasibility and effectiveness are limited. Here, to target the pathological state of the extracellular matrix, we design a protein-based nanofilm-controlled drug delivery system and assemble it on the catheter. This approach, which integrates excellent anti-biofilm properties with stable and controlled drug delivery for tens of days in one step, ensures optimal efficacy and negligible side effects while preventing biofilm-related infections. In a rabbit model of urethral injury, the anti-fibrotic catheter maintains extracellular matrix homeostasis by reducing fibroblast-derived collagen production and enhancing metalloproteinase 1-induced collagen degradation, resulting in a greater improvement in lumen stenosis than other topical therapies for urethral stricture prevention. Such facilely fabricated biocompatible coating with antibacterial contamination and sustained-drug-release functionality could not only benefit populations at high risk of urethral stricture but also serve as an advanced paradigm for a range of biomedical applications.

The Effects of Halofuginone on Wound Healing in the Rat Nasal Mucosa

Background

Halofuginone is an alkaloid febrifugine analogue and bioactive molecule that was isolated incidentally from the Dichroa febrifuga plant. The therapeutic efficacy of halofuginone in parasitic infections, scleroderma, inflammation, and fibrosis-related diseases, as well as in some types of cancer, has been previously reported. The effects of halofuginone on nasal mucosal damage are not yet known.

Objective

The aim of this study was to investigate the potential effect of topically applied halofuginone on wound healing in the mechanically injured nasal mucosa of rats.

Methods

A unilateral mucosal wound was created in the nasal cavity of 32 rats (aged 4 weeks) using the brushing technique. These rats were randomly divided into 4 groups. Although the control group did not receive an intervention, a dry pad, a saline-impregnated pad, or a pad impregnated with halofuginone were placed in the rats of the other 3 groups and left for 5 minutes. Rats were sacrificed on the 14th day, and a histological examination was performed. The nasal mucosa was assessed via hematoxylin-eosin and Masson’s trichrome staining.

Results

There were no statistically significant differences in epithelial thickness, inflammation, goblet cell formation, and epithelial disarray values between the halofuginone group and the control group ( P > .05). The subepithelial thickness was significantly decreased in the saline-treated group and the halofuginone-treated group ( P < .05), but a significantly lower level of subepithelial fibrosis was only observed in the halofuginone group compared to the other groups ( P < .05).

Conclusions

Topical halofuginone administration reduces the development of fibrosis and subepithelial edema after experimentally induced nasal mucosal injury, but it does not exert therapeutic or preventive effects on epithelial damage, inflammation, and goblet cell hyperplasia.

Augmentation Cystoplasty of Diseased Porcine Bladders with Bi-Layer Silk Fibroin Grafts

IMPACT STATEMENT

The search for an ideal "off-the-shelf" biomaterial for augmentation cystoplasty remains elusive and current scaffold configurations are hampered by mechanical and biocompatibility restrictions. In addition, preclinical evaluations of potential scaffold designs for bladder repair are limited by the lack of tractable large animal models of obstructive bladder disease that can mimic clinical pathology. The results of this study describe a novel, minimally invasive, porcine model of partial bladder outlet obstruction that simulates clinically relevant phenotypes. Utilizing this model, we demonstrate that acellular, bi-layer silk fibroin grafts can support the formation of vascularized, innervated bladder tissues with functional properties.

Biologically active quinoline and quinazoline alkaloids part I

Quinoline and quinazoline alkaloids, two important classes of N-based heterocyclic compounds, have attracted tremendous attention from researchers worldwide since the 19th century. Over the past 200 years, many compounds from these two classes were isolated from natural sources, and most of them and their modified analogs possess significant bioactivities. Quinine and camptothecin are two of the most famous and important quinoline alkaloids, and their discoveries opened new areas in antimalarial and anticancer drug development, respectively. In this review, we survey the literature on bioactive alkaloids from these two classes and highlight research achievements prior to the year 2008 (Part I). Over 200 molecules with a broad range of bioactivities, including antitumor, antimalarial, antibacterial and antifungal, antiparasitic and insecticidal, antiviral, antiplatelet, anti-inflammatory, herbicidal, antioxidant and other activities, were reviewed. This survey should provide new clues or possibilities for the discovery of new and better drugs from the original naturally occurring quinoline and quinazoline alkaloids.

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.

Effect of Mitomycin - C and Triamcinolone on Preventing Urethral Strictures

Urethral stricture is a common disease with high recurrence rate. Several manipulations were defined to prevent the recurrence but the results were disappointing. This study aimed to evaluate the efficacy of triamcinolone and mitomycin-C on urethral stricture formation and their effect on inhibition of urethral fibrosis. A total of 24 New Zealand rabbits were divided into 3 groups. Urethras of rabbits were traumatized with pediatric resectoscope. Resection area was irrigated with 10mL saline, swapped with a cotton wool soaked with 0.5mg/mL MMC and injected by 40mg triamcinolone in groups 1, 2 and 3 respectively. Retrograde urethrogram was performed at 28^th day of procedure and the urethra was removed for histopathologic evaluation. There were significant differences in urethral diameters and in lumen reduction rate between the control and study groups (p<0.001). Compared to control group, all treatment groups showed mild fibrosis, less collagen bundle irregularity, and lower numbers of fibroblasts (p=0.003). The Tunnel assay showed that the number of apoptotic cells in the submucosal connective tissue was quantitatively higher in control groups (p=0.034). In the view of efficacy and safety, MMC and triamcinolone have the potential to replace the use of stents, clean intermittent catheterization, or long term catheters following internal urethrotomy. There were no statistically significant differences between two agents in terms of preventing urethral stricture formation in the present study. Mitomycin C and triamcinolone decreased the recurrence rates of urethral stricture.

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.

Docetaxel inhibits urethral stricture formation, an initial study in rabbit model

INTRODUCTION

Urethral stricture, a frequent source of lower urinary tract disorders in men, is still a difficult problem for urologists. Based the anti-restenosis effect of paclitaxel on coronary artery, the role of docetaxel, a semi-synthetic analogue of paclitaxel, in limiting urethral stricture formation was studied.

METHODS

Forty adult New Zealand male rabbits were involved in this study, which were randomly assigned into 3 groups, namely a high dose docetaxel (DH, 0.1 mg/d), a low dose docetaxel (DL, 0.01 mg/d) and a control (C) group, with 16, 16, 8 rabbits in each group, respectively. All animals underwent a 10 mm-long circumferential electrocoagulation of the bulbar urethra with a 13Fr pediatric resectoscope. Drugs were given by urethral irrigation daily and continuous for 28 days. Stricture formation was assessed by retrograde urethrography and videourethroscopy. Urethra pathology was evaluated by hematoxylin and eosin staining and Sirius red staining.

RESULTS

At the end of this study, 15, 14 and 7 rabbits remained for evaluation in DH, DL and C group, respectively. Urethral diameters in DH, DL and C group were (7.17±1.63) mm, (6.55±0.62) mm, (3.23±1.36) mm, with a normal urethral diameter of (9.08±1.29) mm. Lumen reduction in DH, DL and C group were (36.93±11.58)%, (48.03±7.89)% and (84.66±14.95)%, respectively. Statistically difference could be found between every two groups (p<0.05) both in urethral diameters and in lumen reduction, except for compare of urethral diameters between DH and DL group. Histological examination confirmed mass fibrous tissue and collagen content at the stricture sit in C group, whereas less in docetaxel treated rabbits.

CONCLUSIONS

Docetaxel could limit urethral stricture formation, which may be due to inhibition of fibrous tissue and collagen expression. Docetaxel may become a new choice in the prevention of urethral stricture formation.

Adjunctive maneuvers to treat urethral stricture: a review of the world literature

The development of urethral stricture (US) or bladder neck contracture is a relatively uncommon but well described condition observed primarily in men. Despite familiarity with US disease, management remains challenging for urologists. Risk factors for the development of USs or bladder neck contracture include primary treatment modality, tobacco smoking, coronary artery disease and poorly controlled diabetes mellitus. Numerous treatment options exist for this condition that vary in procedural complexity, including intermittent self catheterization (CIC), serial urethral dilation, endoscopic techniques and open reconstructive repairs. Repetitive procedures for this condition may carry increased failure rates and morbidities. For the treatment of refractory or recalcitrant bladder neck contracture, newer intralesional anti-proliferative, anti-scar agents have been used in combination with transurethral bladder neck incisions to augment outcome and long-term effect. The primary focus of this systematic review of the published literature is to streamline and summarize various and newer therapeutic modalities available to manage patients with US or bladder neck contracture.

The effect of antifibrotic drug halofugine on Th17 cells in concanavalin A-induced liver fibrosis

Anti-inflammation strategy is one of the proposed therapeutic approaches to hepatic fibrosis. T helper (Th) 17 cells, which play a detrimental role in experimental murine models of inflammatory diseases, have been demonstrated to participate in the pathogenesis of liver damage. The inhibitory effect of halofuginone (HF), an active component of extracts derived from the plant alkaloid febrifugine, on collagen synthesis has been shown in animal models of the fibrotic disease. The aim of this study was to clarify the in vivo effect of HF on Th17 cells in concanavalin A-induced fibrosis rats. Haematoxylin-eosin (HE) staining and Masson staining were performed to observe collagen deposition. The presence of INF-gamma, TNF-alpha, IL-6, IL-17, IL-1beta, IL-33 and IL-10 in serum and the presence of ROR-γt, IL-17, TGF-β1 and α-SMA in liver tissue were detected. Flow cytometry was performed to analyse the percentage of Th17 cells. We observed significantly lower levels of INF-gamma, TNF-alpha, IL-6, IL-17, IL-1beta, TGF-β1 and α-SMA in HF-treated group of rats, and the percentage of Th17 cells in splenic lymphocyte was decreased well. Histological examination demonstrated that HF significantly reduced the severity of liver fibrosis in HF-treated rats. We concluded that HF (10 mg/kg) exerts an antifibrotic impact on Th17 cells and its relative cytokines in rats with ConA-induced fibrosis.

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.

Comparison of two experimental models for urethral stricture in the anterior urethra of the male rabbit

OBJECTIVE

To compare 2 urethral stricture models and determine the appropriate model for the generation of urethral stricture in rabbits.

METHODS

A total of 28 adult male New Zealand rabbits were included in the present study. They were separated randomly into 3 groups. Urethroscopy was performed using a pediatric resectoscope (13F). In 1 group (10 rabbits), circumferential electrocoagulation of the anterior urethra 2-3 mm long was performed until ulceration of the mucosa occurred. In the second group (10 rabbits), 2-3 mm wide resection from the anterior urethra was performed that was deep enough to expose the periurethral tissue to allow urine leakage from the lumen. The remaining 8 rabbits as the control group underwent only urethroscopy. On the 30th day, retrograde urethrography and urethroscopy were performed to evaluate urethral stricture formation. Histologic examination was done to evaluate the urethral pathologic changes.

RESULTS

According to the urethrography and urethroscopy findings, no rabbits in the electrocoagulation or control group developed urethral stricture; however, significant stricture formation was observed in every case of the electroresection group. Regenerating urothelium at the luminal side of the urethra was seen in 6 rabbits in the electrocoagulation group and 4 showed normal urethra. In the electroresection group, extensive fibrosis that obstructed the urethral lumen and nodular collagen bundles in the urethral wall were seen.

CONCLUSION

The electroresection method is more reliable than the electrocoagulation method in developing urethral stricture in the rabbit model. A 2-3-mm-wide resection from the anterior urethra can successfully generate urethral stricture with respect to electrocoagulation. Electroresection offers an ideal animal model for generating urethral stricture.

Development of a porcine animal model for urethral stricture repair using autologous urothelial cells

OBJECTIVE

To present a versatile large animal model for endoscopic stricture repair using autologous urothelial cells.

MATERIALS AND METHODS

12 male minipigs were used. An artificial stricture model was established using suture-ligation, thermo-coagulation and internal urethrotomy. A vesicostomy served for urinary diversion. Stricture formation was confirmed radiologically and histologically. Autologous urothelial cells were harvested from bladder washings, cultivated and labeled. Internal urethrotomy was done in all, and the cultivated cells were injected into the urethrotomy wound. All animals were sacrificed after 4 or 8 weeks. Immunohistology was done to confirm the presence of autologous urothelial cells within the reconstituted urethra.

RESULTS

Stricture formation was verified with all three methods. Histologically, no significant differences in the severity of stricture development could be observed with regard to the method used. The autologous urothelial cells in the area of the urethrotomy could be detected in the urothelium and the corpus spongiosum until 8 weeks after re-implantation.

CONCLUSIONS

We created a reliable and reproducible porcine model for artificial urethral strictures. Autologous urothelial cells can be implanted into an artificial stricture after urethrotomy. These cells retain their epithelial phenotype and are integrated in the resident urothelium. Further comparative studies are needed to ultimately determine a superior efficacy of this novel approach.

Rapamycin inhibits formation of urethral stricture in rabbits

Rapamycin has been reported to inhibit hepatic fibrosis, lung fibrosis, renal fibrosis, and subglottic stenosis. Fibrosis is also involved in urethral stricture. Therefore, we investigated the effect of rapamycin on the inhibition of urethral stricture formation in a rabbit model. First, models of urethral stricture were successfully established by electrocoagulation of the bulbar urethra in adult New Zealand male rabbits. Forty-six model rabbits were randomly assigned to four groups: high-dose rapamycin (R(H), 1.0 mg/day), low-dose rapamycin (R(L), 0.1 mg/day), dimethyl sulfoxide (DMSO) alone (DMSO, solvent control), and normal saline (NS). Urethral stricture was assessed by a retrograde urethrogram and video-urethroscopy. Urethra pathology was evaluated by hematoxylin and eosin and Sirius red staining. After 28 days of treatment, lumen reduction in the R(H), R(L), DMSO, and NS groups was 36.0, 56.5, 69.1, and 82.9, respectively. Comparison of the rapamycin groups (R(H) and R(L)) and control groups (DMSO and NS) indicated significantly less restriction in the rapamycin groups. Histopathological analysis confirmed the presence of fibroblasts and an increase in collagen at the stricture site in the two control groups but not in the R(H) or R(L) groups. These results indicate that rapamycin inhibits experimentally induced urethral stricture formation in rabbits. This effect may be due to its inhibition of fibroblast proliferation and collagen expression.

Is there any synergic effect for coadministration of mitomycin C and halofuginone on the skin wound healing?

OBJECTIVE

This study compared the potencies of the antifibrotic agents mitomycin C (MMC) and halofuginone (HFN) and investigated whether coadministration of these agents produces synergic effects in an animal skin wound model.

SUBJECTS AND METHODS

Twenty male Sprague-Dawley rats were used for this study. After a full-thickness excisional wound was made on the dorsum of each rat, each rat was treated with topical mitomycin, intraperitoneal HFN, or both. Wound surface areas were measured over time, and histologic analysis was performed after wounds healed completely.

RESULTS

The groups treated with MMC alone, HFN alone, and a combination of the two all exhibited delayed wound healing compared with the untreated group. Histologically, fibrosis and matrix metalloproteinase-2 expression were significantly inhibited in the treated groups. However, there were no gross or histologic differences between the MMC-treated group, the HFN-treated group, and the combination-treatment group.

CONCLUSIONS

Both MMC and HFN inhibited excessive fibrosis. However, there was no significant difference in the antifibrotic effects of MMC and HFN on surgically induced skin wounds. Moreover, combination treatment with both MMC and HFN failed to confer an additional antifibrotic effect on skin wounds when compared with treatment with MMC or HFN alone.

Halofuginone-coated urethral catheters prevent periurethral spongiofibrosis in a rat model of urethral injury

BACKGROUND AND PURPOSE

Urethral strictures are from periurethral spongiofibrosis that develops as a result of urethral trauma, disease, or iatrogenic injury. The spongy tissue that surrounds the strictured urethra has an altered ratio of collagen, with increased collagen type I relative to type III. We evaluated the ability of a urethral catheter that was coated with halofuginone (HF), a potent type I collagen inhibitor, to prevent spongiofibrosis formation in a rat model.

MATERIALS AND METHODS

HF was coated on silicone catheters and release kinetics were measured. Success of impregnation was evaluated with scanning electron microscopy, serial weights, and drug elution data. Urethral strictures were induced in rats using electrocautery. Half the animals had placement of an HF-coated catheter while the others had uncoated silicone controls. Animals were sacrificed at predetermined time points, and urethral tissue was either processed for staining with Masson trichrome and anti-alpha-1 collagen or digested to determine HF concentration. Serum drug levels were also determined in treated animals. Slides were graded by a pathologist who was blinded to treatment to determine collagen deposition.

RESULTS

HF was coated successfully on silicone catheters. Local urethral concentration of HF was tenfold higher than serum concentration in treated rats. Animals with HF-coated catheters had no new type I collagen deposition after urethral injury. Control animals had increased periurethral collagen type I deposition, typical of urethral stricture formation.

CONCLUSIONS

HF can be coated successfully on silicone catheters. HF successfully inhibits periurethral type I collagen deposition after urethral injury. This may become an important therapy to prevent urethral stricture formation or recurrence after endoscopic therapy.

The preventive effect of halofuginone on posterior glottic stenosis in a rabbit model

Objective

The aim of this study was to investigate the preventive effect of halofuginone on posterior glottic stenosis (PGS) in an animal model.

Study Design

A randomized, controlled animal study.

Subjects and Methods

Sixteen male New Zealand White rabbits were used for this study. After the mucosa of posterior glottis was removed for producing PGS, the study group (eight rabbits) was given intraperitoneal halofuginone at 0.1 mg/kg/day for 4 weeks and saline was injected into peritoneum in the control group. At 4 weeks after injury, postsurgical changes of posterior glottis were evaluated by gross and histologic examination.

Results

PGS was induced by the mucosal stripping of the posterior glottis. The halofuginone-treated group showed less scarring and granulation tissue formation. Also, the degree of synechia was significantly less than that of control group. Histologic analysis showed the decreased fibrosis in the halofuginone-treated group.

Conclusion

This study suggests that halofuginone can be helpful in preventing PGS after laryngeal injury.

[Low-dose rate brachytherapy with locally integrated beta emitters after internal urethrotomy. A pilot project using an animal model]

BACKGROUND

The treatment of urethral strictures represents an unsolved urological problem.

PATIENTS AND METHODS

The effect of a (32)P-coated urethral catheter in the sense of low-dose rate brachytherapy to modulate wound healing will be analyzed in an animal experiment.

RESULTS

Unfortunately it is not possible to present any results because this is being studied for the first time and there are no experiences with low-dose rate brachytherapy and this form of application in the lower urinary tract. Furthermore the animal experiment will only start in the near future. Both decade-long experiences with radiotherapy to treat benign diseases and our own results of previous studies in otolaryngology and ophthalmology let us expect a significantly lower formation of urethral strictures after internal urethrotomy.

CONCLUSION

This study will contribute to improving the treatment of urethral strictures as demanded in previous papers.

Effect of intraurethral captopril gel on the recurrence of urethral stricture after direct vision internal urethrotomy: Phase II clinical trial

OBJECTIVE

The purpose of this study is to evaluate the effect of intraurethral captopril gel as an antifibrotic agent on patients with urethral stricture.

MATERIALS AND METHODS

In the first phase of clinical trial, 13 rabbits were included and local side-effects of captopril gel were evaluated. In the second phase, 56 patients were enrolled from April 2004 to January 2006. After internal urethrotomy the patients were classified into three patient groups: (i) received placebo gel (group I); (ii) received 0.1% captopril gel (group II); and (iii) instilled 0.5% captopril gel intraurethrally (group III).

RESULTS

In phase I, no significant local side-effects were seen in the urethra of rabbits. In phase II, the mean age of the patients was 39.5 and the mean follow-up duration was 16 months. The most common etiology of the urethral stricture in the patients was iatrogenic (35.7%), most of their strictures had a depth of 0.5 cm or less (67.8%), and the length of most strictures was between 1 and 2 cm (41.1%). The patients' maximum urine flow increased more in groups II and III, than in group I (P < 0.04, P < 0.05, respectively). The recurrence rate was less in groups II and III than in group I (P < 0.05). In terms of the maximal urine flow and recurrence rate, no significant difference was seen between group II and group III (P = 0.13, P = 0.21, respectively).

CONCLUSION

Captopril gel is a safe, effective and non-toxic agent for decreasing the recurrence rate of the urethral stricture after internal urethrotomy. However, more studies, including more cases and a longer follow up, are needed to prove the effect of captopril gel on patients' urethra.

Effects of halofuginone on fibrosis formation secondary to experimentally induced subglottic trauma

OBJECTIVE

The aim of the study was to assess the antifibrotic effect of systemically applied halofuginone after subglottic injury.

MATERIALS AND METHODS

After standardized trauma to subglottic area, rats were divided into two groups: a study group that received treatment and a control group that did not. The rats were treated with 0.1 mg/kg/day intraperitoneal halofuginone injection for 30 days. The larynx specimens were examined histopathologically under light microscope for epithelization, inflammation, necrosis, and fibrosis.

RESULTS

The fibrosis indexes of the treated group were significantly less than those of the control group (P < .01).

CONCLUSIONS

Systemically applied halofuginone hydrobromide decreases fibrosis/scar tissue formation secondary to experimentally induced acute subglottic trauma.