Surgical option for the correction of Peyronie's disease: an autologous tissue-engineered endothelialized graft

Tissue Engineering for Penile Reconstruction

The penis is a complex organ with a development cycle from the fetal stage to puberty. In addition, it may suffer from either congenital or acquired anomalies. Penile surgical reconstruction has been the center of interest for many researchers but is still challenging due to the complexity of its anatomy and functionality. In this review, penile anatomy, pathologies, and current treatments are described, including surgical techniques and tissue engineering approaches. The self-assembly technique currently applied is emphasized since it is considered promising for an adequate tissue-engineered penile reconstructed substitute.

Innovative Human Three-Dimensional Tissue-Engineered Models as an Alternative to Animal Testing

Animal testing has long been used in science to study complex biological phenomena that cannot be investigated using two-dimensional cell cultures in plastic dishes. With time, it appeared that more differences could exist between animal models and even more when translated to human patients. Innovative models became essential to develop more accurate knowledge. Tissue engineering provides some of those models, but it mostly relies on the use of prefabricated scaffolds on which cells are seeded. The self-assembly protocol has recently produced organ-specific human-derived three-dimensional models without the need for exogenous material. This strategy will help to achieve the 3R principles.

A decade of grafting techniques as a sole treatment for Peyronie's disease

BACKGROUND

Peyronie's disease (PD) can be a cosmetically and functionally devastating condition. Surgical approaches have been proposed in the chronic stages of PD as plication or plaque incision/excision with grafting to preserve penile size in complex cases. Although several surgeons nowadays are inclined toward the utilization of non-autologous grafts owing to the ease of their preparation and availability, synthetic graft procedures still await more technical improvements and supporting evidence before their consideration for standard care.

OBJECTIVES

In this review, our goal is to facilitate an insight into the most promising grafting materials used for the management of PD and techniques associated.

MATERIALS AND METHODS

A PubMed review was conducted for all the studies on our topic within the past ten years (January 2009 until December 2019). The outcome parameters we documented and compared comprised of operative time, follow-up time, postoperative penile cosmesis and function, and, finally, overall patient satisfaction related to each technique.

RESULTS

Our search yielded 23 English-written original study articles in addition to a single case report on the various grafting techniques utilized as the sole treatment for PD, each demonstrating different outcomes and points of comparison.

CONCLUSION

A successful grafting procedure for PD requires an appropriately tailored surgical modality and an experienced surgeon. Nevertheless, proper preoperative patient counseling on all aspects of his condition and opted treatment modality while setting clear and realistic expectations remains key for overall patient satisfaction.

Towards clinical application of tissue engineering for erectile penile regeneration

Penile wounds after traumatic and surgical amputation require reconstruction in the form of autologous tissue transfers. However, currently used techniques are associated with high infection rates, implant erosion and donor site morbidity. The use of tissue-engineered neocorpora provides an alternative treatment option. Contemporary tissue-engineering strategies enable the seeding of a biomaterial scaffold and subsequent implantation to construct a neocorpus. Tissue engineering of penile tissue should focus on two main strategies: first, correcting the volume deficit for structural integrity in order to enable urinary voiding in the standing position and second, achieving erectile function for sexual activity. The functional outcomes of the neocorpus can be addressed by optimizing the use of stem cells and scaffolds, or alternatively, the use of gene therapy. Current research in penile tissue engineering is largely restricted to rodent and rabbit models, but the use of larger animal models should be considered as a better representation of the anatomical and physiological function in humans. The development of a cell-seeded scaffold to achieve and maintain erection continues to be a considerable challenge in humans. However, advances in penile tissue engineering show great promise and, in combination with gene therapy and surgical techniques, have the potential to substantially improve patient outcomes.

Contemporary surgical and non-surgical management of Peyronie's disease

Numerous treatments have been proposed for Peyronie's disease (PD). As the evidence base has expanded, the field of operative and non-operative options for patients has narrowed. Collagenase clostridium hystolyticum (CCH) injection now comprises the medical option, and surgical possibilities entail penile plication, plaque incision/excision and grafting, and prosthesis implantation. Still, questions abound regarding the optimal approach and indication for each of these treatments. We conducted a review of literature exploring the contemporary management of PD with a particular focus on work since the last American Urologic Association's (AUA) guidelines update for PD. Recent results and discussion indicate trends toward minimal invasiveness, toward a more holistic approach to the PD patient, and away from algorithmic management, galvanized, in part, by data challenging long-held beliefs.

Feasibility of Polycaprolactone Scaffolds Fabricated by Three-Dimensional Printing for Tissue Engineering of Tunica Albuginea

PURPOSE

To investigate the feasibility of a polycaprolactone (PCL) scaffold fabricated by three-dimensional (3D) printing for tissue engineering applications for tunica albuginea.

MATERIALS AND METHODS

PCL scaffolds were fabricated by use of a 3D printing system. Two scaffolds were fabricated that differed in the architecture of the lay-down pattern: a 90°PCL scaffold and a 45°PCL scaffold. Mechanical properties were measured to compare tensile strength between the two scaffold types. The scaffolds were characterized by scanning electron microscope (SEM) images. The scaffolds were seeded with fibroblast cells, and the ability of these scaffolds to support the cells was evaluated by immunofluorescence staining.

RESULTS

The PCL scaffolds had well-structured shapes, regular arrays, and good interconnection in SEM images. The horizontal and vertical Young's modulus coefficients were 13 and 12 MPa for the 90°PCL scaffold and 19 and 21 MPa for the 45°PCL scaffold, respectively. Microscopy images revealed that human fibroblast cells covered the entire scaffold surface. Immunofluorescence staining of ER-TR7 confirmed that the fibroblast cells remained viable and proliferated throughout the time course of the culture.

CONCLUSIONS

This preliminary study provides experimental evidence for the feasibility of 3D printing of PCL scaffolds for tissue engineering applications of tunica albuginea.

Stem cell therapy for the treatment of Peyronie's disease

INTRODUCTION

Like other fibrotic diseases, the cause of Peyronie's disease (PD) is still obscure. Since there is now increasing evidence for the role of Mesenchymal Stem Cells (MSCs) as potential treatment to fibrosis, it is crucial to determine their possible efficacy in the treatment of PD. Areas covered: In this review, the authors summarize the emerging data and published studies regarding the use of SCs for the treatment of PD. The authors provide particular focus on the three-first experimental studies for the use of SCs in rat models as well as the sole two studies undertaken in humans. Expert opinion: It seems evident in experimental settings that SCs in general (Adipose Derived SCs in particular) provide a feasible, safe and effective therapy for PD. The potential limits of the rat models used initially have been somewhat overcome with the inception of studies in men. However, further prospective studies are needed in humans to further elucidate the therapeutic potential of stem cell therapy in PD.

Novel three-dimensional autologous tissue-engineered vaginal tissues using the self-assembly technique

Many diseases necessitate the substitution of vaginal tissues. Current replacement therapies are associated with many complications. In this study, we aimed to create bioengineered neovaginas with the self-assembly technique using autologous vaginal epithelial (VE) and vaginal stromal (VS) cells without the use of exogenous materials and to document the survival and incorporation of these grafts into the tissues of nude female mice. Epithelial and stromal cells were isolated from vaginal biopsies. Stromal cells were driven to form collagen sheets, 3 of which were superimposed to form vaginal stromas. VE cells were seeded on top of these stromas and allowed to mature in an air-liquid interface. The vaginal equivalents were implanted subcutaneously in female nude mice, which were sacrificed after 1 and 2 weeks after surgery. The in vitro and animal-retrieved equivalents were assessed using histologic, functional, and mechanical evaluations. Vaginal equivalents could be handled easily. VE cells formed a well-differentiated epithelial layer with a continuous basement membrane. The equivalent matrix was composed of collagen I and III and elastin. The epithelium, basement membrane, and stroma were comparable to those of native vaginal tissues. The implanted equivalents formed mature vaginal epithelium and matrix that were integrated into the mice tissues. Using the self-assembly technique, in vitro vaginal tissues were created with many functional and biological similarities to native vagina without any foreign material. They formed functional vaginal tissues after in vivo animal implantation. It is appropriate for vaginal substitution and disease modeling for infectious studies, vaginal applicants, and drug testing.

Grafting techniques for Peyronie's disease

Peyronie’s disease (PD) is a benign fibrotic condition of the penile tunica albuginea. PD can be associated with penile pain, curvature, shortening, and erectile dysfunction (ED). The predominant and most bothersome symptom in affected patients is penile curvature, which can lead to inability to have sexual intercourse. In such cases, surgical correction of the curvature may be required. Plication techniques to correct curvature can cause penile shortening and therefore are generally reserved for curvatures <60°. Penile prosthesis implantation with simultaneous correction of curvature by various means is recommended in PD patients with ED not responding to medical therapy. Grafting techniques are the preferred surgical treatment in patients with penile curvatures >60°, short penis, or hourglass deformity. Patients scheduled for grafting surgery are required to have satisfactory erectile rigidity preoperatively. There are various grafting materials that can be used for closure of the tunica albuginea defect following plaque incision/excision. Both autologous and non-autologous grafts have been used for PD reconstructive surgery, and each graft has its advantages and disadvantages. Novel grafting materials are presented and discussed in this review. A major advantage of the available “off-the-shelf” grafts is that there is no harvesting from a donor site and, thus, morbidity is reduced, and operative times are minimized. Further investigations in regard to tissue-engineered grafts to improve surgical handling and postoperative outcomes are ongoing. Surgeon experience, careful patient selection, patient preference and type of penile deformity affect the choice of graft. This review summarizes the literature within the past 5 years regarding grafting techniques in PD. Surgical outcomes and limitations of grafting techniques are reported. A major objective of this review is dedicated to preoperative considerations and indications for grafting procedures, with the aim to improve surgical outcomes and increase patient satisfaction. Proper postoperative management of patients after incision/excision and grafting is important to avoid early and long-term complications and unwanted outcomes. This review provides an overview of recent advances and recommendations in regard to rehabilitation strategies after grafting procedures. Adequate preoperative patient counseling, careful patient selection, appropriate indications, and postoperative management is key to optimal surgical outcomes with high satisfaction rates after grafting techniques in PD surgery.

Surgical management of Peyronie's disease

Peyronie's disease (PD) has a significant impact on the quality of life of both patients and their partners due to the compromised sexual function and physical deformation resulting from the condition. PD is a connective tissue disorder marked by fibrotic healing of the tunica albuginea, leading to penile deformities including curvature, shortening, loss of girth, hourglass appearance, and hinging. Despite the multiple medical therapies available, surgery is the gold standard of treatment once the plaque has stabilized. We present a review of the disease process, preoperative evaluation, operative planning, surgical treatments with outcomes and complications, and nascent developments in surgical management and graft development. Options include tunical lengthening procedures, tunical shortening procedures, and penile prosthesis. Decision-making is governed by degree of curvature, erectile function, and associated penile deformities. In cases with curvature of less than 60-70 degrees, adequate penile length, and no hourglass deformity, patients are candidates for tunical shortening procedures. Patients with curvature greater than 60-70 degrees, penile hourglass or hinge-destabilizing deformities, and adequate erectile function should be counseled with regard to tunical lengthening procedures. Patients with poor preoperative erectile function should undergo inflatable penile prosthesis placement, with possible secondary straightening procedures. Technique selection should be based upon surgeon preference, expertise, and experience, as evidence does not necessarily support one procedure over another.

Tissue engineering of urinary bladder and urethra: advances from bench to patients

Urinary tract is subjected to many varieties of pathologies since birth including congenital anomalies, trauma, inflammatory lesions, and malignancy. These diseases necessitate the replacement of involved organs and tissues. Shortage of organ donation, problems of immunosuppression, and complications associated with the use of nonnative tissues have urged clinicians and scientists to investigate new therapies, namely, tissue engineering. Tissue engineering follows principles of cell transplantation, materials science, and engineering. Epithelial and muscle cells can be harvested and used for reconstruction of the engineered grafts. These cells must be delivered in a well-organized and differentiated condition because water-seal epithelium and well-oriented muscle layer are needed for proper function of the substitute tissues. Synthetic or natural scaffolds have been used for engineering lower urinary tract. Harnessing autologous cells to produce their own matrix and form scaffolds is a new strategy for engineering bladder and urethra. This self-assembly technique avoids the biosafety and immunological reactions related to the use of biodegradable scaffolds. Autologous equivalents have already been produced for pigs (bladder) and human (urethra and bladder). The purpose of this paper is to present a review for the existing methods of engineering bladder and urethra and to point toward perspectives for their replacement.

Extracorporeal shock wave therapy in Peyronie's disease: results of a placebo-controlled, prospective, randomized, single-blind study

INTRODUCTION

Extracorporeal shock wave therapy (ESWT) for treatment of Peyronie's disease (PD) is controversial.

AIM

To study the efficacy of ESWT by a placebo-controlled, randomized trial.

METHODS

Patients with PD (n=102) were randomly assigned (n=51) to each group (ESWT or placebo). All patients were given 6 weekly treatments. Patients in the ESWT-group received 2,000 shock waves per session, using the Piezoson 100 lithotripter (Richard Wolf, Knittlingen, Germany). Patients in the placebo-group were treated with interposition of a plastic membrane, which prevented any transmission of shock waves.

MAIN OUTCOME MEASURES

Primary end point was decrease of pain between baseline and after 4 weeks follow-up. Secondary end points were changes in deviation, plaque size, and sexual function. Pain was assessed by a visual analog scale. Deviation was measured by a goniometer after artificial erection using Alprostadil (Viridal®, Schwarz Pharma, Monheim, Germany). Plaque size was measured with a ruler and sexual function assessed by a scale regarding the ability to perform sexual intercourse.

RESULTS

Overall, only 45 patients experienced pain at baseline. In the subgroup analysis of these patients, pain decreased in 17/20 (85.0%) patients in the ESWT group and 12/25 (48.0%) patients in the placebo group (P=0.013, relative risk [RR]=0.29, 95% confidence interval: 0.09-0.87). Penile deviation was not reduced by ESWT (P=0.66) but worsened in 20/50 (40%) and 12/49 (24.5%) patients of the ESWT and placebo-group, respectively (P=0.133). Plaque size reduction was not different between the two groups (P=0.33). Additional, plaque size increased in five patients (10.9%) of the ESWT group only. An improvement in sexual function could not be verified (P=0.126, RR=0.46).

CONCLUSIONS

Despite some potential benefit of ESWT in regard to pain reduction, it should be emphasized that pain usually resolves spontaneously with time. Given this and the fact that deviation may worsen with ESWT, this treatment cannot be recommended.

An endothelialized urothelial cell-seeded tubular graft for urethral replacement

INTRODUCTION

Many efforts are used to improve surgical techniques and graft materials for urethral reconstruction. We developed an endothelialized tubular structure for urethral reconstruction.

METHODS

Two tubular models were created in vitro. Human fibroblasts were cultured for 4 weeks to form fibroblast sheets. Then, endothelial cells (ECs) were seeded on the fibroblast sheets and wrapped around a tubular support to form a cylinder for the endothelialized tubular urethral model (ET). No ECs were added in the standard tubular model (T). After 21 days of maturation, urothelial cells were seeded into the lumen of both models. Constructs were placed under perfusion in a bioreactor for 1 week. At several times, histology and immunohistochemistry were performed on grafted nude mice to evaluate the impact of ECs on vascularization.

RESULTS

Both models produced an extracellular matrix, without exogenous material, and developed a pseudostratified urothelium. Seven days after the graft, mouse red blood cells were present only in the outer layers in T model, but in the full thickness of ET model. After 14 days, erythrocytes were present in both models, but in a greater proportion in ET model. At day 28, both models were well-vascularized, with capillary-like structures in the whole thickness of the tubes.

CONCLUSION

Incorporating endothelial cells was associated with an earlier vascularization of the grafts, which could decrease the necrosis of the transplanted tissue. As those models can be elaborated with the patient's cells, this tubular urethral graft would be unique in its autologous property.

Surgical Management for Peyronie's Disease

Peyronie's disease is a common debilitating condition for both men and their partners that results in penile deformity and compromises sexual functioning. While there are a myriad of medical therapeutic options, these have not been demonstrated to correct the deformity and restore sexual function definitively. As such, surgery is the mainstay of treatment for this disease, and multiple surgical approaches may be considered depending on disease characteristics, patient co-morbidity, and findings on preoperative diagnostic testing. The purpose of this review is to highlight the different surgical approaches and different procedures within each approach, and to examine important issues for surgeons to consider for administering the best treatment that restores function while reconciling patient expectations.

Surgery for Peyronie's disease

Peyronie's disease (PD) is most simply referred to as a fibrotic wound-healing disorder of the tunica albuginea. It is both a physically and psychologically devastating disorder that causes penile deformity, curvature, hinging, narrowing and shortening, which may compromise sexual function. Although a variety of non-surgical treatments have been suggested, none to date offer a reliable and effective correction of the penile deformity. As a result, surgery remains the gold standard treatment option, offering the most rapid and reliable treatment which will be the focus of this article. We review the preoperative evaluation, surgical algorithm, graft materials and postoperative management of PD. Outcomes for tunical shortening, tunical lengthening and penile prosthesis placement for penile straightening are reviewed. Tunica albuginea plication is the preferred method of straightening for men with adequate rigidity and less severe disease defined as curvature less than 70° without narrowing/hinging. Men who have more severe, complex deformity, but maintain strong preoperative erectile function should be considered candidates for straightening with plaque incision or partial excision and grafting. Finally, for those men who have inadequate rigidity and PD, penile prosthesis placement with straightening is the best approach to address both problems.

Intratunical injection of human adipose tissue-derived stem cells prevents fibrosis and is associated with improved erectile function in a rat model of Peyronie's disease

BACKGROUND

Peyronie's disease (PD) is a connective tissue disorder of the tunica albuginea (TA). Currently, no gold standard has been developed for the treatment of the disease in its active phase.

OBJECTIVE

To test the effects of a local injection of adipose tissue-derived stem cells (ADSCs) in the active phase of a rat model of PD on the subsequent development of fibrosis and elastosis of the TA and underlying erectile tissue.

DESIGN, SETTING, AND PARTICIPANTS

A total of 27 male 12-wk-old Sprague-Dawley rats were divided in three equal groups and underwent injection of vehicle (sham), 0.5-μg [corrected] transforming growth factor (TGF)-β1 in a 50-μl vehicle in either a PD or a PD plus ADSC group in the dorsal aspect of the TA.

INTERVENTION

The sham and PD groups were treated 1 d after TGF-β1 injection with intralesional treatment of vehicle, and the PD plus ADSC group received 1 million human-labeled ADSCs in the 50-μl vehicle. Five weeks after treatment, six rats per group underwent erectile function measurement. Following euthanasia, penises were harvested for histology and Western blot.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The ratio of intracavernous pressure to mean arterial pressure (ICP/MAP) upon cavernous nerve stimulation, elastin, and collagen III protein expression and histomorphometric analysis of the penis. Statistical analysis was performed by analysis of variance followed by the Tukey-Kramer test for post hoc comparisons or the Mann-Whitney test when applicable.

RESULTS AND LIMITATIONS

Erectile function significantly improved after ADSC treatment (ICP/MAP 0.37 in PD vs 0.59 in PD plus ADSC at 5-V stimulation; p=0.03). PD animals developed areas of fibrosis and elastosis with a significant upregulation of collagen III and elastin protein expression. These fibrotic changes were prevented by ADSC treatment.

CONCLUSIONS

This study is the first to test stem cell therapy in an animal model of PD. Injection of ADSCs into the TA during the active phase of PD prevents the formation of fibrosis and elastosis in the TA and corpus cavernosum.

Emerging tools for erectile dysfunction: a role for regenerative medicine

Erectile dysfunction (ED) is the most common sexual disorder reported by men to their health-care providers and the most investigated male sexual dysfunction. Currently, the treatment of ED focuses on 'symptomatic relief' of ED and, therefore, tends to provide temporary relief rather than providing a cure or reversing the cause. The identification of a large population of "difficult-to-treat" patients has triggered researchers to identify novel treatment approaches, which focus on cure and restoration of the underlying cause of ED. Regenerative medicine has developed extensively in the past few decades and preclinical trials have emphasized the benefit of growth factor therapy, gene transfer, stem cells and tissue engineering for the restoration of erectile function. Development of clinical trials involving immunomodulation in postprostatectomy ED patients and the use of maxi-K channels for gene therapy are illustrative of the advances in the field. However, the search for novel treatment targets and a wealth of preclinical studies represent a dynamic and continuing field of enquiry.

The role of Nesbit's procedure in surgical reconstruction of penile deviation

Objective: We review our results after surgical reconstruction with the Nesbit’s procedure for congenital or acquired penile deviation.

Patients and methods: Etiology of penile deviation, surgical outcome for straightening the penis, postoperative patient satisfaction and clinical findings were evaluated for 5 patients undergoing Nesbit’s procedure followed by a Medline review of contemporary literature regarding alternative surgical techniques. Follow-up included clinical examination, self-photography on erection and a standardized interview with erectile dysfunction assessment using IIEF-5 questionnaire.

Results: Overall patient satisfaction was 100% in two patients, 2 patients were partly satisfied and 1 patient reported no satisfaction because of severe penile shortening with insufficiency for sexual intercourse postoperatively. Preoperative mean angulation of the penis was 42°. Four patients had Peyronie’s disease and 1 patient’s curvature resulted from an untreated penile fracture during sexual intercourse.

Conclusion: The Nesbit technique can give satisfactory results for mild and moderate penile curvature. However, each technique for the reconstruction of penile deviation has its own advantages and disadvantages. Therefore proper patient selection has a major impact on further outcome.

Tissue engineering for penile surgery: comparative study of noncellular and cell-seeded synthetic grafts for tunica albuginea replacement

INTRODUCTION

Surgical treatment outcomes in Peyronie's disease remain controversial because of high rates of recurrence.

AIM

The aim of this study was to engineer in vitro a new type of tunica albuginea (TA) autologous graft obtained by culture of autologous fibroblast on a polyglycolic acid (PGA) scaffold. This engineering graft was compared with PGA with morphological and functional outcomes for TA replacement, 4 months after graft upon corpus cavernosum in a rat model.

METHODS

Thirty-nine Sprague Dawley adult male rats were divided into four groups: (i) control group (C) with resection and resuture of a 5 mm long and 2 mm large piece of original TA; (ii) PGA scaffold group (P) with the same resection of TA and suture of PGA scaffold; (iii) autologous fibroblast-seeded on PGA scaffold graft after resection of the same piece of TA (F + P); and (iv) sham group for functional and histological comparison.

MAIN OUTCOME MEASURE

The main outcome measure was assessment of graft size variation at 4 months and comparison between the three test groups. The secondary objective is assessment of erectile function by measuring erectile response to cavernous nerve electrical stimulation in each group.

RESULTS

At 4 months, there was a significant difference in graft area retraction between the groups (P = 0.0081) with higher retraction in P group vs. in C or F + P groups. Erectile response to cavernous nerve stimulation significantly differed between the groups and was sham equivalent to C equivalent to F + P superior to P group.

CONCLUSIONS

This study provides experimental evidence for the feasibility and the functionality of fibroblast-seeded scaffold compared with acellular graft for TA replacement.