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

3D-printed perfused models of the penis for the study of penile physiology and for restoring erectile function in rabbits and pigs

The intricate topology of vascular networks and the complex functions of vessel-rich tissues are challenging to reconstruct in vitro. Here we report the development of: in vitro pathological models of erectile dysfunction and Peyronie's disease; a model of the penis that includes the glans and the corpus spongiosum with urethral structures; and an implantable model of the corpus cavernosum, whose complex vascular network is critical for erectile function, via the vein-occlusion effect. Specifically, we 3D printed a hydrogel-based corpus cavernosum incorporating a strain-limiting tunica albuginea that can be engorged with blood through vein occlusion. In corpus cavernosum defects in rabbits and pigs, implantation of the 3D-printed tissue seeded with endothelial cells restored normal erectile function on electrical stimulation of the cavernous nerves as well as spontaneous erectile function within a few weeks of implantation, which allowed the animals to mate and reproduce. Our findings support the further development of 3D-printed blood-vessel-rich functional organs for transplantation.

Corpus cavernosum and tunica albuginea reconstruction by tissue engineering: towards functional erectile structures regeneration

BACKGROUND

Current treatments for penile erectile structures reconstruction are limited and remain a great challenge in clinical practice. Tissue engineering techniques using different seed cells and scaffolds to construct a neo-tissue open promising avenues for penile erectile structures repair and replacement and show great promise in the restoration of: structure, mechanical property, and function which matches the original tissue.

METHODS

A comprehensive literature review was conducted by accessing the NCBI PubMed, Cochrane, and Google Scholar databases from January 1, 1990, to January, 1, 2022 using the search terms "Tissue engineering, Corpus cavernosum (CC), Tunica albuginea (TA), Acellular Matrix, Penile Reconstruction". Articles were screened and assessed by two independent reviewers to determine whether those met the inclusion criteria, and a total of 19 articles were being selected and included in the data analysis.

RESULTS

Tissue engineered cell-seeded scaffold can reconstruct a similar structure to native TA and CC and showed good histocompatibility with no immunological rejection. The results of the evaluation of morphological feature, intracavernosal pressure, and erectile-related nitric oxide (NO) expression were strongly proofs that the tissue engineered graft can significantly improve the penile erectile and ejaculatory function. In addition, increasing the purity of seed cells, improving the mechanical properties of the scaffold, providing appropriate induction for stem cells, and optimizing cell delivery systems are potential approaches to improve reconstructive outcomes. Currently, a larger animal model, comparable in size to the human penis, is needed to test the feasibility of the engineered grafts.

CONCLUSION

Our review summarized the research in tissue engineering of CC and TA. It showed great promise in reconstructing the functional structures and restoring the erection and ejaculatory function. With continuous advancement in the field, tissue-engineered penile erectile structures hold substantial potential to enhance clinical outcomes for patients.

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.

Tissue anisotropy and collagenomics in porcine penile tunica albuginea: Implications for penile structure-function relationships and tissue engineering

The tunica albuginea (TA) of the penis is an elastic layer that serves a structural role in penile erection. Disorders affecting the TA cause pain, deformity, and erectile dysfunction. There is a substantial clinical need for engineered replacements of TA, but data are scarce on the material properties and biochemical composition of healthy TA. The objective of this study was to assess tissue organization, protein content, and mechanical properties of porcine TA to establish structure-function relationships and design criteria for tissue engineering efforts. TA was isolated from six pigs and subjected to histomorphometry, quantification of collagen content and pyridinoline crosslinks, bottom-up proteomics, and tensile mechanical testing. Collagen was 20 ± 2%/wet weight (WW) and 53 ± 4%/dry weight (DW). Pyridinoline content was 426 ±131 ng/mg WW, 1011 ± 190 ng/mg DW, and 45 ± 8 mmol/mol hydroxyproline. Bottom-up proteomics identified 14 proteins with an abundance of >0.1% of total protein. The most abundant collagen subtype was type I, representing 95.5 ± 1.5% of the total protein in the samples. Collagen types III, XII, and VI were quantified at 1.7 ± 1.0%, 0.8 ± 0.2%, and 0.4 ± 0.2%, respectively. Tensile testing revealed anisotropy: Young's modulus was significantly higher longitudinally than circumferentially (60 ± 18 MPa vs. 8 ± 5 MPa, p < 0.01), as was ultimate tensile strength (16 ± 4 MPa vs. 3 ± 3 MPa, p < 0.01). Taken together, the tissue mechanical and compositional data obtained in this study provide important benchmarks for the development of TA biomaterials. STATEMENT OF SIGNIFICANCE: The tunica albuginea of the penis serves an important structural role in physiologic penile erection. This tissue can become damaged by disease or trauma, leading to pain and deformity. Treatment options are limited. Little is known about the precise biochemical composition and biomechanical properties of healthy tunica albuginea. In this study, we characterize the tissue using proteomic analysis and tensile testing to establish design parameters for future tissue engineering efforts. To our knowledge, this is the first study to quantify tissue anisotropy and to use bottom-up proteomics to characterize the composition of penile tunica albuginea.

A Preliminary Study of Constructing the Tissue-Engineered Corpus Cavernosum With Autologous Adipose Stem Cells In Vivo

Introduction

The autologous skin flap is still the mainstream method for penile reconstruction, but it is very difficult to reconstruct a functional corpus cavernosum. Tissue engineering provides a new idea aiming to restore the damaged or absent corpus cavernosum.

Aim

To assess the feasibility of constructing the tissue-engineered corpus cavernosum with autologous adipose stem cells in a rabbit model.

Methods

A total of 30 New Zealand male white rabbits. Among them, 20 rabbits were used to obtain the original corpus cavernosum which were used to prepare the acellular corporal scaffolds (ACSs). The others were used for acquiring autologous adipose stem cells (ADSCs) and constructing tissue-engineered corpus cavernosum in vivo.

Outcome

ACSs were obtained from rabbit penile tissues through an established decellularization procedure. Rabbit autologous ADSCs as seed cells were harvested and expanded. The ADSCs seeded and unseeded ACSs were implanted back into the intramuscular and subcutaneous site in vivo, and the tissue-engineered corpus cavernosum was harvested and analyzed with gross morphology, histological staining, and real-time PCR assay after 1, 3, and 6 months.

Results

ACSs were successfully prepared. The cell non-cytotoxicity and integrity of micro-architecture of ACSs was confirmed in vitro. The cell-seeded scaffold in the intramuscular group was considered as the better strategy for constructing the tissue-engineered corpus cavernosum compared with the other groups. Some α-SMA and CD31 positive cells were detected and identified by immunofluorescent staining and real-time PCR assay in the tissue-engineered corpus cavernosum.

Clinical Translation

This study provides a new method for constructing the tissue-engineered corpus cavernosum.

Strengths and Limitations

First, it is urgent to improve the transformation rate of the endothelial cells and smooth muscle cells from ADSCs. Second, the scaffold harvested in this study was not a complete matrix. Third, further study is needed to explore the potential mechanism of which scaffolds are more suitable for living in intramuscular rather than subcutaneous environment.

Conclusion

In this study, we used the autologous ADSCs as seed cells, the acellular corpus cavernosum as scaffolds, and implanted the grafts back into the rabbit model to preliminarily construct the tissue-engineered corpus cavernosum. This study would provide help for further development in tissue-engineered corpus cavernosum.

Cao Z, Liu L, Jiao H, et al. A Preliminary Study of Constructing the Tissue-Engineered Corpus Cavernosum With Autologous Adipose Stem Cells In Vivo. Sex Med 2022;10:100563.

Co-culture of smooth muscle cells and endothelial cells on three-dimensional bioprinted polycaprolactone scaffolds for cavernosal tissue engineering

PURPOSE

In vitro evaluation of polycaprolactone (PCL) scaffolds fabricated by a three-dimensional (3D) printing technique for tissue engineering applications in the corpus cavernosum.

MATERIALS AND METHODS

PCL scaffolds were fabricated by use of a 3 D bioprinting system. The 3D-printed scaffolds had interconnected structures for cell ingrowth. Human aortic smooth muscle cells (haSMCs) were seeded on the scaffold and cultured for 5 days, and then human umbilical vein endothelial cells (HUVECs) were also added on the scaffolds and co-cultured with haSMCs for up to 7 days. The ability of these scaffolds to support the growth of HUVECs and haSMCs was investigated in vitro. 3 D strand-deposited scaffolds were characterized by scanning electron microscopy (SEM) images and porosity measurement.

RESULTS

SEM images showed the surface of the PCL scaffolds to be well covered by HUVECs and haSMCs. Immunofluorescent staining of α-flk1 and α-smooth muscle actin on the HUVECs and haSMCs seeded scaffolds confirmed that the cells remained viable and proliferated throughout the time course of the culture.

CONCLUSION

3 D bioprinting of a PCL scaffold is feasible for co-culturing of HUVECs and haSMCs. This was a preliminary study to investigate the possibility of fabrication of tissue-engineered corpus cavernosum.

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.

Microsurgical tunica albuginea transplantation in an animal model

Several andrological diseases require surgical repair or reconstruction of tunica albuginea, which envelops the corpora cavernosa penis. Despite intense research efforts involving a variety of biological materials, such as skin, muscle aponeurosis, human dura mater, tunica vaginalis, and pericardium, engineered tunica albuginea suitable for graft use is yet to be obtained. The study investigates microsurgical tunica albuginea allotransplantation in an animal model with the purpose of creation of an organ-specific tissue bank to store penile tissue, from cadaveric donors and male-to-female trans-sexual surgery, for allogeneic transplantation. Materials were tunica albuginea tissue explanted from 15 donor rats, cryopreserved at -80°C, gamma-irradiated, and implanted in 15 recipient rats, of which three rats were used as controls. Penile grafts were explanted at different time intervals; after macroscopic evaluation of the organ, the grafts were processed to morphological, histochemical, and immunohistochemical examinations by light microscopy. Detection of pro-inflammatory cytokines was also performed. Examination of the tunica albuginea allografts collected 1, 3, or 6 months after surgery and of control tunica albuginea fragments showed that tunica albuginea implants achieved biointegration with adjacent tissue at all-time points. The integration of cryopreserved rat tunica albuginea allografts, documented by our study, encourages the exploration of tunica albuginea allotransplantation in humans. In conclusion, the effectiveness and reliability of the tunica albuginea conditioning protocol described here suggest the feasibility of setting up a tunica albuginea bank as a further tissue bank.

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.

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.

Outcomes of surgical treatment of Peyronie's disease

The aims of the present review were to assess the literature on published outcomes and complications associated with surgical treatments for Peyronie's disease (PD) and to assist clinicians in the effective management of PD by increasing understanding and awareness of the outcomes associated with current surgical treatment options. A PubMed literature search was conducted to identify relevant, peer-reviewed clinical and review articles published between January 1980 and October 2013 related to outcomes of surgical correction of PD. Search terms for this non-systematic review included 'Peyronie's disease', 'outcomes', 'complications', 'erectile dysfunction or ED', 'patient expectation', and 'patient satisfaction'; search terms were searched separately and in combination. Case studies and editorials were excluded, primary manuscripts and reviews were included, and bibliographies of articles of interest were reviewed and key references were obtained. Assessment of the study design, methodology, clinical relevance and impact on the surgical outcomes of PD was performed on the sixty-one articles that were selected and analysed. Currently, there are several investigational minimally invasive and non-surgical treatment options for PD; however, surgical treatment remains the standard of care for patients with stable disease and disabling deformity or drug-resistant erectile dysfunction. Each of the different surgical procedures that are used for treatment of PD, including tunical shortening, tunical lengthening (plaque incisions or partial excision and grafting), and use of inflatable penile prostheses, carries its own advantages and disadvantages in terms of potential complications and postoperative satisfaction. Because of the variety of ways that PD may present in affected patients, no single, standard, surgical treatment for this disorder has prevailed and multiple variations of each type of procedure may exist. Surgical outcomes of the most commonly used procedures are not substantially different; therefore, the appropriateness of each treatment option may often depend on disease and patient characteristics (e.g. deformity and erectile function). Surgical algorithms have been published to guide surgeons and patients through the selection of surgical procedures in the absence of conclusive, long-term outcome data. Accumulating data on outcomes associated with established procedures, modifications to these procedures, and new surgical techniques and materials may serve to further guide practice and refine evidence-based selection of the surgical approach.

Understanding the course of Peyronie's disease

AIMS

To correct common misconceptions about Peyronie's disease (PD) that present obstacles to early recognition and treatment.

METHODS

The prevalence, natural disease course, psychosocial effects and treatment considerations for patients with PD were reviewed.

RESULTS

Studies over the past decade have shown that the prevalence of PD may be higher (up to 20%) than previously thought. PD can lead to emotional and relationship distress. Nearly 10% of men who present with PD are younger than 40. Both younger age and comorbid vascular disease have been associated with more severe and progressive PD. In the majority of patients, symptoms will either deteriorate or remain stable. PD is often associated with erectile dysfunction (ED). Effective, minimally invasive treatments used early in the disease course include unapproved and/or investigational intralesional injection therapy with verapamil, interferon (IFN) α-2b, or collagenase clostridium histolyticum (CCH). Surgical intervention is considered in patients with ED and/or penile deformity that impairs sexual functioning; however, preoperative discussion of appropriate expectations is important.

DISCUSSION

The availability of effective minimally invasive and surgical therapies for PD suggests that active management should be considered over a 'wait-and-see' approach.

CONCLUSION

Providing early intervention and improved education/awareness of PD as a chronic and progressive disorder may result in improved physical and psychosocial outcomes for PD patients. As general practitioners are often the first contact for men with PD, they are well positioned to recognise symptoms early and promptly refer patients for further evaluation and treatment.

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.

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.