The mechanisms and potential of stem cell therapy for penile fibrosis

Autophagy in erectile dysfunction: focusing on apoptosis and fibrosis

In most types of erectile dysfunction, particularly in advanced stages, typical pathological features observed are reduced parenchymal cells coupled with increased tissue fibrosis. However, the current treatment methods have shown limited success in reversing these pathologic changes. Recent research has revealed that changes in autophagy levels, along with alterations in apoptosis and fibrosis-related proteins, are linked to the progression of erectile dysfunction, suggesting a significant association. Autophagy, known to significantly affect cell fate and tissue fibrosis, is currently being explored as a potential treatment modality for erectile dysfunction. However, these present studies are still in their nascent stage, and there are limited experimental data available. This review analyzes erectile dysfunction from a pathological perspective. It provides an in-depth overview of how autophagy is involved in the apoptotic processes of smooth muscle and endothelial cells and its role in the fibrotic processes occurring in the cavernosum. This study aimed to develop a theoretical framework for the potential effectiveness of autophagy in preventing and treating erectile dysfunction, thus encouraging further investigation among researchers in this area.

Stem cell therapy in diabetic men with erectile dysfunction: a 24-month follow-up of safety and efficacy of two intracavernous autologous bone marrow derived mesenchymal stem cells injections, an open label phase 2 clinical trial

BACKGROUND

Recently we reported results of phase 1 pilot clinical trial of 2 consecutive intracavernous (IC) injection of autologous bone marrow-derived mesenchymal stem cells (BM-MSCs) for the first time in the treatment of diabetic patients with erectile dysfunction (DM-ED). In phase 2 of this study our aim is to evaluate long term safety and efficacy of IC injections of BM-MSC on additional eight patients with DM-ED.

RESULTS

Each patient received 2 consecutive IC injections of BM-MSC and evaluated at 1, 3, 6, 12, and 24-month time points. Primary outcome was the tolerability and safety of stem cells therapy (SCT), while the secondary outcome was improvement of erectile function (EF) as assessed using the International Index of Erectile Function-5 (IIEF-5), Erection Hardness Score (EHS) questionnaires, and Color Duplex Doppler Ultrasound (CDDU). IC injections of BM-MSCs was safe and well-tolerated. Minor local and short-term adverse events related to the bone marrow aspiration and IC injections were observed and treated conservatively. There were significant improvement in mean IIEF-5, EHS, all over the follow-up time points in comparison to the baseline. At 24-month follow up there were significant decline in the mean IIEF-5, and EHS compared to the baseline. The mean basal and 20-min peak systolic velocity was significantly higher at 3-month after the IC injections compared to baseline.

CONCLUSIONS

This phase 2 clinical trial confirmed that IC injections of BM-MSC are safe and improve EF. The decline in EF over time suggests a need for assessing repeated injections.

CLINICAL TRIAL REGISTRATION

NCT02945462.

LncRNA MALAT1 facilitates BM-MSCs differentiation into endothelial cells and ameliorates erectile dysfunction via the miR-206/CDC42/PAK1/paxillin signalling axis

BACKGROUND

Erectile dysfunction (ED) is a common male sexual dysfunction, with an increasing incidence, and the current treatment is often ineffective.

METHODS

Vascular endothelial growth factor (VEGFA) was used to treat bone marrow-derived mesenchymal stem cells (BM-MSCs), and their cell migration rates were determined by Transwell assays. The expression of the von Willebrand Factor (vWF)VE-cadherin, and endothelial nitric oxide synthase(eNOS) endothelial markers was determined by qRT‒PCR and Western blot analyses. The MALAT1-induced differentiation of BM-MCs to ECs via the CDC42/PAK1/paxillin pathway was explored by transfecting VEGFA-induced BM-MSC with si-MALAT1 and overexpressing CDC42 and PAK1. The binding capacity between CDC42, PAK1, and paxillin in VEGFA-treated and non-VEGFA-treated BM-MSCs was examined by protein immunoprecipitation. MiR-206 was overexpressed in VEGFA-induced BM-MSC, and the binding sites of MALAT1, miR-206, and CDC42 were identified using a luciferase assay. Sixty male Sprague‒Dawley rats were divided into six groups (n = 10/group). DMED modelling was demonstrated by APO experiments and was assessed by measuring blood glucose levels. Erectile function was assessed by measuring the intracavernosa pressure (ICP) and mean arterial pressure (MAP). Penile erectile tissue was analysed by qRT‒PCR, Western blot analysis, and immunohistochemical staining.

RESULTS

MALAT1 under VEGFA treatment conditions regulates the differentiation of BM-MSCs into ECs by modulating the CDC42/PAK1/paxillin axis. In vitro experiments demonstrated that interference with CDC42 and MALAT1 expression inhibited the differentiation of BM-MSCs to ECs. CDC42 binds to PAK1, and PAK1 binds to paxillin. In addition, CDC42 in the VEGFA group had a greater ability to bind to PAK1, whereas PAK1 in the VEGFA group had a greater ability to bind to paxillin. Overexpression of miR-206 in VEGFA-induced BM-MSCs demonstrated that MALAT1 competes with the CDC42 3'-UTR for binding to miR-206, which in turn is involved in the differentiation of BM-MSCs to ECs. Compared to the DMED model group, the ICP/MAP ratio was significantly greater in the three BM-MSCs treatment groups.

CONCLUSIONS

MALAT1 facilitates BM-MSC differentiation into ECs by regulating the miR-206/CDC42/PAK1/paxillin axis to improve ED. The present findings revealed the vital role of MALAT1 in the repair of BM-MSCs for erectile function and provided new mechanistic insights into the BM-MSC-mediated repair of DMED.

Temporal gene signature of myofibroblast transformation in Peyronie's disease: first insights into the molecular mechanisms of irreversibility

BACKGROUND

Transformation of resident fibroblasts to profibrotic myofibroblasts in the tunica albuginea is a critical step in the pathophysiology of Peyronie's disease (PD). We have previously shown that myofibroblasts do not revert to the fibroblast phenotype and we suggested that there is a point of no return at 36 hours after induction of the transformation. However, the molecular mechanisms that drive this proposed irreversibility are not known.

AIM

Identify molecular pathways that drive the irreversibility of myofibroblast transformation by analyzing the expression of the genes involved in the process in a temporal fashion.

METHODS

Human primary fibroblasts obtained from tunica albuginea of patients with Peyronie's disease were transformed to myofibroblasts using transforming growth factor beta 1 (TGF-β1). The mRNA of the cells was collected at 0, 24, 36, 48, and 72 hours after stimulation with TGF-β1 and then analyzed using a Nanostring nCounter Fibrosis panel. The gene expression results were analyzed using Reactome pathway analysis database and ANNi, a deep learning-based inference algorithm based on a swarm approach.

OUTCOMES

The study outcome was the time course of changes in gene expression during transformation of PD-derived fibroblasts to myofibroblasts.

RESULTS

The temporal analysis of the gene expression revealed that the majority of the changes at the gene expression level happened within the first 24 hours and remained so throughout the 72-hour period. At 36 hours, significant changes were observed in genes involved in MAPK-Hedgehog signaling pathways.

CLINICAL TRANSLATION

This study highlights the importance of early intervention in clinical management of PD and the future potential of new drugs targeting the point of no return.

STRENGTHS AND LIMITATIONS

The use of human primary cells and confirmation of results with further RNA analysis are the strengths of this study. The study was limited to 760 genes rather than the whole transcriptome.

CONCLUSION

This study is to our knowledge the first analysis of temporal gene expression associated with the regulation of the transformation of resident fibroblasts to profibrotic myofibroblasts in PD. Further research is warranted to investigate the role of the MAPK-Hedgehog signaling pathways in reversibility of PD.

Intraoperative bioprinting of human adipose-derived stem cells and extra-cellular matrix induces hair follicle-like downgrowths and adipose tissue formation during full-thickness craniomaxillofacial skin reconstruction

Craniomaxillofacial (CMF) reconstruction is a challenging clinical dilemma. It often necessitates skin replacement in the form of autologous graft or flap surgery, which differ from one another based on hypodermal/dermal content. Unfortunately, both approaches are plagued by scarring, poor cosmesis, inadequate restoration of native anatomy and hair, alopecia, donor site morbidity, and potential for failure. Therefore, new reconstructive approaches are warranted, and tissue engineered skin represents an exciting alternative. In this study, we demonstrated the reconstruction of CMF full-thickness skin defects using intraoperative bioprinting (IOB), which enabled the repair of defects via direct bioprinting of multiple layers of skin on immunodeficient rats in a surgical setting. Using a newly formulated patient-sourced allogenic bioink consisting of both human adipose-derived extracellular matrix (adECM) and stem cells (ADSCs), skin loss was reconstructed by precise deposition of the hypodermal and dermal components under three different sets of animal studies. adECM, even at a very low concentration such as 2 % or less, has shown to be bioprintable via droplet-based bioprinting and exhibited de novo adipogenic capabilities both in vitro and in vivo. Our findings demonstrate that the combinatorial delivery of adECM and ADSCs facilitated the reconstruction of three full-thickness skin defects, accomplishing near-complete wound closure within two weeks. More importantly, both hypodermal adipogenesis and downgrowth of hair follicle-like structures were achieved in this two-week time frame. Our approach illustrates the translational potential of using human-derived materials and IOB technologies for full-thickness skin loss.

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.

Patients' attitude with surgery for Peyronie's disease: results from a multicentric European study

BACKGROUND

Despite the existence of conservative therapies for Peyronie's disease (PD), surgery is commonly utilized for the treatment of bothersome curvatures due to its potential effectiveness, although it carries intrinsic risks and may not universally lead to satisfactory outcomes.

AIM

To explore the rate and factors influencing patients' willingness to undergo surgery for PD.

METHODS

Data were prospectively collected in 5 European academic centers between 2016 and 2020. Data included age, time from PD onset, penile pain, curvature degree, difficulty at penetration, hourglass deformity, erectile dysfunction (ED), and previous treatments. All patients were offered conservative treatments, either medications or injections. Tunical shortening or lengthening procedures were offered as an alternative to conservative treatments, when indicated. Penile prosthesis was offered to those with concomitant ED. Patients' attitudes with surgery were recorded. Logistic regression analyses tested the profile of patients who were more likely to be willing to undergo surgery.

OUTCOMES

Patients' willingness to undergo surgery for PD.

RESULTS

This study included 343 patients with a median age of 57.3 years (IQR, 49.8-63.6) and a median penile curvature of 40.0° (IQR, 30.0°-65.0°). Overall, 161 (47%) experienced penetration difficulties and 134 (39%) reported ED. Additionally, hourglass deformity and penile shortening were reported by 48 (14%) and 157 (46%), respectively. As for previous treatments, 128 (37%) received tadalafil once daily; 54 (16%) and 44 (13%), intraplaque verapamil and collagenase injections; and 30 (9%), low-intensity shock wave therapy. Significant curvature reduction (≥20°) was observed in 69 (20%) cases. Only 126 (37%) patients were open to surgery for PD when suggested. At logistic regression analysis after adjusting for confounders, younger age (odds ratio [OR], 0.97; 95% CI, 0.95-1.00; P = .02), more severe curvatures (OR, 1.04; 95% CI, 1.03-1.06; P < .0001), and difficulty in penetration (OR, 1.88; 95% CI, 1.04-3.41; P = .03) were associated with a greater attitude to consider surgical treatment.

CLINICAL IMPLICATIONS

The need for effective nonsurgical treatments for PD is crucial, as is comprehensive patient counseling regarding surgical risks and benefits, particularly to younger males with severe curvatures.

STRENGTHS AND LIMITATIONS

Main limitations are the cross-sectional design and the potential neglect of confounding factors.

CONCLUSIONS

Patients with PD, having a lower inclination toward surgery, emphasize the need for effective nonsurgical alternatives and accurate counseling on the risks and benefits of PD surgery, particularly for younger men with severe curvatures.

The Cavernous Nerve Injury Rat Model: A Pictorial Essay on Post-Radical Prostatectomy Erectile Dysfunction Research

Understanding and addressing post-radical prostatectomy (RP) erectile dysfunction (ED) is of paramount importance for clinicians. Cavernous nerve (CN) injury rat model studies have provided consistently promising experimental data regarding regaining erectile function (EF) after nerve damage-induced ED. However, these findings have failed to translate efficiently into clinical practice, with post-RP ED therapeutic management remaining cumbersome and enigmatic. This disparity highlights the need for further standardization and optimization of the elaborate surgical preparation protocols and multifaceted reporting parameters involved in reliable CN injury rat model experimentation. Even so, despite its technical complexity, this animal model remains instrumental in exploring the functional implications of RP, i.e., surgical lesions of the neurovascular bundles (NVBs). Herein, besides cavernous nerve (CN) dissection, injury, and electrostimulation, multiple pressure measurements, i.e., mean arterial pressure (MAP) and intra-cavernosal pressure (ICP), must also be achieved. A transverse cervical incision allows for carotid artery cannulation and MAP measurements. Conversely, ICP measurements entail circumcising the penis, exposing the ischiocavernous muscle, and inserting a needle into the corporal body. Finally, using an abdominal incision, the prostate is revealed, and the major pelvic ganglia (MPG) and CNs are dissected bilaterally. Specific surgical techniques are used to induce CN injuries. Herein, we provide a narrative and illustrative overview regarding these complex experimental procedures and their particular requirements, reflecting on current evidence and future research perspectives.

News and future perspectives of non-surgical treatments for erectile dysfunction

The significant discontinuation rate of available therapies and the paucity of curative options promoted the research on potential novel treatments suitable for erectile dysfunction patients. The aim of this study was to provide a summary of available evidence regarding the news and future perspectives related to the non-surgical treatment of erectile dysfunction. A narrative review of the literature was performed. A comprehensive search in the MEDLINE, Embase, and Scopus databases was done. Papers in English-language, published until April 2022, were included. No chronological restriction was applied. Retrospective and prospective clinical studies, as well as meta-analyses, were considered. Oro-dispersible formulations of phosphodiesterase type 5 inhibitors are particularly indicated in patients who have difficulty in swallowing solid dosage form; in addition, they constitute a discrete route of administration not requiring water. Low-intensity extracorporeal shock wave therapy is indicated in mild vasculogenic erectile dysfunction and in patients with vasculogenic erectile dysfunction poorly responsive to phosphodiesterase type 5 inhibitors. Stem cell therapy, platelet-rich plasma injections, and gene therapy seem promising regenerative treatments for selected patients with erectile dysfunction. Novel oral formulations of drugs commonly used in erectile dysfunction patients have recently become part of standard clinical practice. Regenerative treatments have been emerging in recent years and could become routine curative options in the near future. Further well-designed randomized controlled trials are needed to provide conclusive evidence on this topic and guide appropriate recommendations.

Therapeutic potential of mesenchymal stem cell-derived exosomal miR-296-5p and miR-337-3p in age-related erectile dysfunction via regulating PTEN/PI3K/AKT pathway

Mesenchymal stem cells (MSCs) are viewed as an increasingly promising treatment for age-related erectile dysfunction (AED). Owing to the limitations of injecting living cells, the injection of exosomes appears to be a more plausible option. However, whether MSC-derived exosomes (MSC-Exos) improve AED and their potential mechanism remains unknown. MSC-Exos were prepared and injected intracavernously into aged rats to determine their effects on AED. Masson's trichrome staining was used to ascertain the changes in the histological structure of the corpus cavernosum. Then miRNA sequencing of MSC-Exos and analysis of the critical exosomal miRNAs were performed, as well as their target pathway enrichment analysis. Real-time quantitative PCR (RT-qPCR) and Western blot assay were performed to reveal the functions of MSC-Exos in regulating the PTEN/PI3K/AKT signaling pathway. Moreover, the effects of MSC-Exos on the corpus cavernosum smooth muscle cells (CCSMCs) apoptosis are explored in vitro. The experimental data validate that intracavernous injection of MSC-Exos ameliorated erectile function in AED rats. Masson's trichrome staining shows MSC-Exos therapy restores the histological structure of the corpus cavernosum by improving the ratios of smooth muscle to collagen. The exosomal miR-296-5p and miR-337-3p target and inhibit PTEN, modulating the PI3K/AKT signaling pathway. Furthermore, exosomes inhibit the apoptosis of CCSMCs. Our findings suggest that MSC-Exos improve AED by delivering miR-296-5p and miR-337-3p to regulate the PTEN/PI3K/AKT signaling pathway. These results bode well for the therapeutic potential of MSC-Exos for AED treatment.

Intraoperative Bioprinting of Human Adipose-derived Stem cells and Extra-cellular Matrix Induces Hair Follicle-Like Downgrowths and Adipose Tissue Formation during Full-thickness Craniomaxillofacial Skin Reconstruction

Craniomaxillofacial (CMF) reconstruction is a challenging clinical dilemma. It often necessitates skin replacement in the form of autologous graft or flap surgery, which differ from one another based on hypodermal/dermal content. Unfortunately, both approaches are plagued by scarring, poor cosmesis, inadequate restoration of native anatomy and hair, alopecia, donor site morbidity, and potential for failure. Therefore, new reconstructive approaches are warranted, and tissue engineered skin represents an exciting alternative. In this study, we demonstrated the reconstruction of CMF full-thickness skin defects using intraoperative bioprinting (IOB), which enabled the repair of defects via direct bioprinting of multiple layers of skin on immunodeficient rats in a surgical setting. Using a newly formulated patient-sourced allogenic bioink consisting of both human adipose-derived extracellular matrix (adECM) and stem cells (ADSCs), skin loss was reconstructed by precise deposition of the hypodermal and dermal components under three different sets of animal studies. adECM, even at a very low concentration such as 2% or less, has shown to be bioprintable via droplet-based bioprinting and exhibited de novo adipogenic capabilities both in vitro and in vivo . Our findings demonstrate that the combinatorial delivery of adECM and ADSCs facilitated the reconstruction of three full-thickness skin defects, accomplishing near-complete wound closure within two weeks. More importantly, both hypodermal adipogenesis and downgrowth of hair follicle-like structures were achieved in this two-week time frame. Our approach illustrates the translational potential of using human-derived materials and IOB technologies for full-thickness skin loss.

Combining transcriptomic analysis and network pharmacology to explore the mechanism by which Shaofu Zhuyu decoction improves diabetes mellitus erectile dysfunction

BACKGROUND

Erectile dysfunction is common among the complications of diabetes mellitus. Shaofu Zhuyu decoction (SFZYD) is commonly used to treat diabetic mellitus erectile dysfunction (DMED). However, its main active components and specific mechanism are still unknown.

PURPOSE

To confirm the activity of SFZYD in improving DMED, explore the main active components of SFZYD, and clarify the underlying mechanism.

METHODS

A diabetic rat model was induced with streptozotocin (STZ). After intragastric administration, erectile function was assessed by the maximum intracavernous pressure (ICPmax)/mean arterial pressure (MAP). Corpus cavernosum fibrosis was evaluated by Masson staining, and ELISA methods were used to determine the serum levels of IL-6, TNF-α, IL-10, IL-4 and IL-1β to evaluate inflammation. Then, the main active components of SFZYD were identified by UPLC‒MS/MS. Finally, the target and biological mechanism of SFZYD in improving DMED were predicted by combined network pharmacology and transcriptomics, which was also validated by molecular docking and cellular thermal shift assay (CETSA) experiments.

RESULTS

SFZYD significantly improved erectile dysfunction and inhibited inflammatory responses and local tissue fibrosis in diabetic rats. A total of 1846 active components were identified by UPLC‒MS/MS, and isorhamnetin was the main active component. The transcriptomic results were used to identify differentially expressed genes among the control, DM and SFZYD groups, and 1264 differentially expressed genes were obtained from the intersection. The network pharmacology results showed that SFZYD acts on core targets such as AKT1, ALB, HSP90AA1 and ESR1 through core components such as isorhamnetin, quercetin and chrysophanic acid. Further combined analysis revealed that multiple targets, such as CYP1B1, DPP4, NOS2 and LCN2, as well as the regulation of the PI3K-AKT signaling pathway, may be important mechanisms by which SFZYD improves DMED. Molecular docking verification showed that isorhamnetin, the key component of SFZYD, has good binding ability with several core targets, and its binding ability with CYP1B1 was the strongest. The CETSA results showed that isorhamnetin binds to CYP1B1 in CCECs.

CONCLUSION

SFZYD improves DMED, inhibits the inflammatory response and alleviates local tissue fibrosis. The combined application of transcriptomic, network pharmacology, molecular docking and CETSA approaches was helpful for revealing the mechanism by which SFZYD improves DMED, which may be related to the regulation of CYP1B1 and the PI3K-Akt signaling pathway.

New therapeutic approaches against pulmonary fibrosis

Pulmonary fibrosis is the end-stage change of a large class of lung diseases characterized by the proliferation of fibroblasts and the accumulation of a large amount of extracellular matrix, accompanied by inflammatory damage and tissue structure destruction, which also shows the normal alveolar tissue is damaged and then abnormally repaired resulting in structural abnormalities (scarring). Pulmonary fibrosis has a serious impact on the respiratory function of the human body, and the clinical manifestation is progressive dyspnea. The incidence of pulmonary fibrosis-related diseases is increasing year by year, and no curative drugs have appeared so far. Nevertheless, research on pulmonary fibrosis have also increased in recent years, but there are no breakthrough results. Pathological changes of pulmonary fibrosis appear in the lungs of patients with coronavirus disease 2019 (COVID-19) that have not yet ended, and whether to improve the condition of patients with COVID-19 by means of the anti-fibrosis therapy, which are the questions we need to address now. This review systematically sheds light on the current state of research on fibrosis from multiple perspectives, hoping to provide some references for design and optimization of subsequent drugs and the selection of anti-fibrosis treatment plans and strategies.

Ultrasound-targeted microbubble destruction mediates PDE5i/NO integration for cavernosum remodeling and penile rehabilitation

Erectile dysfunction (ED) caused by cavernous nerve injury (CNI) is refractory to heal mainly ascribed to the adverse remodeling of the penis induced by ineffectual microvascular perfusion, fibrosis, and neurotrophins scarcity in cavernosum. Phosphodiesterase type V inhibitors (PDE5i) have been regarded as an alternative candidate drug for avoiding penile neuropathy. However, the therapeutic efficacy is severely limited due to poor accumulation under systemic medication and endogenous nitric oxide (NO) deficiency in cavernosum. Herein, an innovative liposomal microbubble (MB) loaded with both Sildenafil (one of PDE5i) and NO was designed. Ultrasound-targeted MB destruction (UTMD)-mediated efficient release and integration erectogenic agents into corpus cavernosum with high biosafety. On a bilateral CNI rat model, the multifunctional MB-cooperated UTMD improved microvascular perfusion in penis, simultaneously, alleviated hypoxia and oxidative stress, indicating successful activation of NO-cyclic guanosine monophosphate pathway. Also, evaluation of the endothelial/muscular composition, intracavernosal pressure, and neural integrity in the penis proved that coordinated intervention reversed the abnormal structural remodeling and promoted the recovery of functional erection. Our work demonstrates that MB loading Sildenafil and NO combined with UTMD hold great promise to "awaken" the efficacy of PDE5i in neurogenic ED, which provided a superior option for ensuring penile rehabilitation.

Rats, Neuregulins and Radical Prostatectomy: A Conceptual Overview

In the contemporary era of early detection, with mostly curative initial treatment for prostate cancer (PC), mortality rates have significantly diminished. In addition, mean age at initial PC diagnosis has decreased. Despite technical advancements, the probability of erectile function (EF) recovery post radical prostatectomy (RP) has not significantly changed throughout the last decade. Due to virtually unavoidable intraoperative cavernous nerve (CN) lesions and operations with younger patients, post-RP erectile dysfunction (ED) has now begun affecting these younger patients. To address this pervasive limitation, a plethora of CN lesion animal model investigations have analyzed the use of systemic/local treatments for EF recovery post-RP. Most promisingly, neuregulins (NRGs) have demonstrated neurotrophic effects in both neurodegenerative disease and peripheral nerve injury models. Recently, glial growth factor 2 (GGF2) has demonstrated far superior, dose-dependent, neuroprotective/restorative effects in the CN injury rat model, as compared to previous therapeutic counterparts. Although potentially impactful, these initial findings remain limited and under-investigated. In an effort to aid clinicians, our paper reviews post-RP ED pathogenesis and currently available therapeutic tools. To stimulate further experimentation, a standardized preparation protocol and in-depth analysis of applications for the CN injury rat model is provided. Lastly, we report on NRGs, such as GGF2, and their potentially revolutionary clinical applications, in hopes of identifying relevant future research directions.

Heterogeneity of fibroblasts is a hallmark of age-associated erectile dysfunction

BACKGROUND

The prevalence of age-associated erectile dysfunction (ED) increases pronouncedly with age. However, the cellular composition and transcriptomic changes of aging penile corpus cavernosum remain largely unclear.

METHODS

Herein, we performed single cell sequencing penile corpus cavernosum from five young with normal erectile response and five old rats with ED.

RESULTS

Clustering analysis identified 19 cell types, such as fibroblasts, myofibroblasts and immune cells. We next revealed their transcriptomic alterations and investigated novel subpopulations of major cell types. Among them, fibroblasts possessed the largest cell number and showed apparent heterogeneity. By performing single-cell entropy analysis on fibroblasts, we observed the age-associated decrease of entropy, and aged fibroblasts were found to adopt senescent secretory phenotype, as evidenced by the high expression of genes associated with the senescence-associated secretory phenotype (SASP). Finally, we constructed a comprehensive intercellular communication network and highlighted key mediators of crosstalk between fibroblasts and other cell types.

CONCLUSIONS

We plotted a cellular atlas of aging cells within penile corpus cavernosum, especially fibroblasts. Our work will deepen the understanding of the heterogeneity among certain cell types within aged penile corpus cavernosum, which will generate positive effects on the future treatment of age-associated ED.

Emerging structural and pathological analyses on the erectile organ, corpus cavernous containing sinusoids

Background

The corpus cavernosum (CC) containing sinusoids plays fundamental roles for erection. Analysis of pathological changes in the erectile system is studied by recent experimental systems. Various in vitro models utilizing genital mesenchymal-derived cells and explant culture systems are summarized.

Methods

3D reconstruction of section images of murine CC was created. Ectopic chondrogenesis in aged mouse CC was shown by a gene expression study revealing the prominent expression of Sox9. Various experimental strategies utilizing mesenchyme-derived primary cells and tissue explants are introduced.

Main Findings

Possible roles of Sox9 in chondrogenesis and its regulation by several signals are suggested. The unique character of genital mesenchyme is shown by various analyses of external genitalia (ExG) derived cells and explant cultures. Such strategies are also applied to the analysis of erectile contraction/relaxation responses to many signals and aging process.

Conclusion

Erectile dysfunction (ED) is one of the essential topics for the modern aged society. More comprehensive studies are necessary to reveal the nature of the erectile system by combining multiple cell culture strategies.

The Current Role and Implications of Stem Cell Therapy in Erectile Dysfunction: A Transformation from Caterpillar to Butterfly Is Required

Current noninvasive treatments for erectile dysfunction (ED) include oral medications, intracavernosal injections, and vacuum-assisted devices. Although these therapies work well for many, some patients experience side effects or are unsatisfied with these therapeutic modalities. Restorative therapies are the newest frontier for ED treatments and are focused on regenerating injured tissue and delivering a possible "cure". Stem cell therapy is a regenerative treatment aimed at restoring normal erectile physiology and curing ED. It is promising in cell-based and animal studies and has now been studied in humans. Although the clinical results are not robust, future research may shed more light on the efficacy of this treatment for ED. PATIENT SUMMARY: Stem cell therapy is a promising regenerative treatment for erectile dysfunction, but the clinical results are not robust. It is currently considered an experimental treatment and should not be used outside a clinical trial setting.

Anti-fibrotic effect of adipose-derived stem cells on fibrotic scars

BACKGROUND

Sustained injury, through radiotherapy, burns or surgical trauma, can result in fibrosis, displaying an excessive deposition of extracellular matrix (ECM), persisting inflammatory reaction, and reduced vascularization. The increasing recognition of fibrosis as a cause for disease and mortality, and increasing use of radiotherapy causing fibrosis, stresses the importance of a decent anti-fibrotic treatment.

AIM

To obtain an in-depth understanding of the complex mechanisms underlying fibrosis, and more specifically, the potential mechanisms-of-action of adipose-derived stomal cells (ADSCs) in realizing their anti-fibrotic effect.

METHODS

A systematic review of the literature using PubMed, Embase and Web of Science was performed by two independent reviewers.

RESULTS

The injection of fat grafts into fibrotic tissue, releases ADSC into the environment. ADSCs’ capacity to directly differentiate into key cell types (e.g., ECs, fibroblasts), as well as to secrete multiple paracrine factors (e.g., hepatocyte growth factor, basis fibroblast growth factor, IL-10), allows them to alter different mechanisms underlying fibrosis in a combined approach. ADSCs favor ECM degradation by impacting the fibroblast-to-myofibroblast differentiation, favoring matrix metalloproteinases over tissue inhibitors of metalloproteinases, positively influencing collagen organization, and inhibiting the pro-fibrotic effects of transforming growth factor-β1. Furthermore, they impact elements of both the innate and adaptive immune response system, and stimulate angiogenesis on the site of injury (through secretion of pro-angiogenic cytokines like stromal cell-derived factor-1 and vascular endothelial growth factor).

CONCLUSION

This review shows that understanding the complex interactions of ECM accumulation, immune response and vascularization, is vital to fibrosis treatments’ effectiveness like fat grafting. It details how ADSCs intelligently steer this complex system in an anti-fibrotic or pro-angiogenic direction, without falling into extreme dilation or stimulation of a single aspect. Detailing this combined approach, has brought fat grafting one step closer to unlocking its full potential as a non-anecdotal treatment for fibrosis.

Indications and characteristics of penile traction and vacuum erection devices

A variety of devices are available for the management of patients with erectile dysfunction, Peyronie's disease, penile dysmorphophobia, for support before and after penile prosthesis insertion, and after radical prostatectomy. Traction devices include, but are not limited to, Penimaster PRO (MSP Concept, Berlin, Germany), Andropenis and Andropeyronie (Andromedical, Madrid, Spain), and the Restorex (PathRight Medical, Plymouth, USA). The other type of devices are vacuum devices such the Osbon ErecAid (Timm Medical, MN, USA). Different devices are optimal for different clinical applications, and robust and contemporary clinical data show a variety of strengths and weaknesses for each device. Research currently favours the use of traction devices for improvement of penile curvature and erectile function in patients with Peyronie's disease compared with vacuum devices; Penimaster Pro and Restorex have been shown to be associated with the best outcomes in this indication. Vacuum devices are favoured for treatment of erectile dysfunction and penile length loss after radical prostatectomy; the Osbon ErecAid is the most well-studied device for this indication. Research into other uses of vacuum and traction devices, such as for penile dysmorphophobia or before and after penile prosthesis, is very limited. Compliance, cost and availability remain substantial challenges, and further high-quality evidence is required to clarify the role of traction devices in urology and sexual medicine.

Single-Cell RNA Sequencing of Human Corpus Cavernosum Reveals Cellular Heterogeneity Landscapes in Erectile Dysfunction

PURPOSE

To assess the diverse cell populations of human corpus cavernosum in patients with severe erectile dysfunction (ED) at the single-cell level.

METHODS

Penile tissues collected from three patients were subjected to single-cell RNA sequencing using the BD Rhapsody™ platform. Common bioinformatics tools were used to analyze cellular heterogeneity and gene expression profiles from generated raw data, including the packages Seurat, Monocle, and CellPhoneDB.

RESULTS

Disease-related heterogeneity of cell types was determined in the cavernous tissue such as endothelial cells (ECs), smooth muscle cells, fibroblasts, and immune cells. Reclustering analysis of ECs identified an arteriole ECs subcluster and another one with gene signatures of fibroblasts. The proportion of fibroblasts was higher than the other cell populations and had the most significant cellular heterogeneity, in which a distinct subcluster co-expressed endothelial markers. The transition trajectory of differentiation from smooth muscle cells into fibroblasts was depicted using the pseudotime analysis, suggesting that the expansion of corpus cavernosum is possibly compromised as a result of fibrosis. Cell-cell communications among ECs, smooth muscle cells, fibroblasts, and macrophages were robust, which indicated that inflammation may also have a crucial role in the development of ED.

CONCLUSIONS

Our study has demonstrated a comprehensive single-cell atlas of cellular components in human corpus cavernosum of ED, providing in-depth insights into the pathogenesis. Future research is warranted to explore disease-specific alterations for individualized treatment of ED.

Molecular Mechanisms and Current Pharmacotherapy of Peyronie's Disease: A Review

Peyronie’s disease (PD) is a localized fibrotic lesion of the penis that has adverse effects on men’s health. In this review, we summarized the molecular mechanisms and pharmacotherapies of PD. A literature search was conducted using PubMed and Cochrane Library during 2001–2020. Although no oral or topical medication demonstrated efficacy in monotherapy of PD, several intralesional medications have yielded promising results. Currently, the effective strategy in management of PD should be combined modality therapy, including but not limited to pharmacotherapy, mechanical therapy, and psychotherapy. Meanwhile, basic research is still necessary to facilitate the development of novel and more reliable treatments. In future, more attention should be given simultaneously to epigenetic changes, inflammatory cytokines, the abnormal wound-healing process, and profibrotic and anti-fibrotic factors to provide more options for this refractory disease.

Single-cell Transcriptomics Uncover a Novel Role of Myeloid Cells and T-lymphocytes in the Fibrotic Microenvironment in Peyronie's Disease

BACKGROUND

Peyronie's disease (PD) is an acquired fibrotic disease affecting the penile tunica albuginea that can lead to curvature and deformities, shortening, and erectile dysfunction. Although immunological mechanisms have been suggested for the pathophysiology of PD, these have not been investigated using single-cell transcriptomics.

OBJECTIVE

To investigate the immunological signature of plaques from PD patients using immunohistochemistry (IHC) and single-cell RNA sequencing (scRNA-Seq).

DESIGN, SETTING, AND PARTICIPANTS

Tunica albuginea biopsy was performed in patients undergoing penile surgery for either PD (n = 12) or plication or penile cancer (control, n = 6). The inclusion criteria for PD patients were stable chronic disease (≥12 mo in duration) and no previous penile surgery or intralesional injection therapy.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

IHC was performed on surgical samples from ten patients with PD and five control subjects. An additional two PD and one control sample were used for scRNA-Seq (droplet-based; 10X Genomics). Cell clusters were visualised using heatmaps and t-distributed stochastic neighbour embedding plots (BioTuring v2.7.5).

RESULTS AND LIMITATIONS

IHC revealed the presence of myeloid dendritic cells (DCs; CD68⁺, TLR4⁺, CD206⁺), cytotoxic T lymphocytes (CTLs; CD3⁺, CD8⁺), and B lymphocytes (CD20⁺) in PD plaques, which were absent in controls. scRNA-Seq yielded results for 3312 PD and 5658 control cells. Cell clusters contained fibroblasts (COL1A2⁺), myofibroblasts (COL1A2⁺, ACTA2⁺), smooth muscle cells (ACTA2⁺, DES⁺), endothelial cells (VWF⁺), myeloid cells (CD14⁺), T lymphocytes (CD3D⁺), and neutrophils (ALPL⁺). Myeloid cell subclustering showed infiltration of monocyte-derived cells; control tissue contained classical DCs and resident macrophages. Lymphocyte subclustering revealed mucosal-associated invariant T (MAIT) cells and CTLs in PD. Differential gene expression suggests an increase in inflammatory and immune responses in chronic PD. The study is limited by the small scRNA-seq sample size (n = 3) for IHC, mitigated by a larger cohort of historic paraffin-embedded samples (n = 15), which showed largely parallel findings. Owing to tissue stiffness and extracellular matrix adhesion, our single-cell yield was lower for PD than for the control sample.

CONCLUSIONS

Our data suggest that even in the chronic PD stage (painless and stable curvature) there is a sustained inflammatory reaction. While vascularisation and collagen production are elevated, the inflammation is driven by specialised monocyte-derived CTL and MAIT cells. These findings could uncover new avenues for medical treatment of PD.

PATIENT SUMMARY

We looked at the role of the immune system in patients suffering from Peyronie's disease, a condition causing shortening and curvature of the penis. We found that even in a stable, chronic stage of the disease, there is activation of the immune system. Our results suggest that there is potential for novel treatments for this condition.

Ectopic Germinal Centres with B and T Cells and Follicular Dendritic Cell Networks in Urethral Stricture Tissue: Possible Avenue for Immunological Treatments

BACKGROUND

The underlying cause of a urethral stricture can sometimes be obscure. It is possible that an injury to the urethra induces an immunological cascade that generates scar tissue and fibrosis, eventually resulting in a stricture. If such immunological reactions could be better elucidated, immunological therapies could possibly emerge.

OBJECTIVE

To evaluate if ectopic germinal centres exist in urethral stricture disease.

DESIGN SETTING AND PARTICIPANTS

Resected stricture specimens from 45 patients undergoing open bulbar urethroplasty with excision and anastomosis were assessed. Histopathological characteristics, such as fibrosis (grade I-III), inflammation, and sclerosis, were evaluated using immunostaining for CD3 (T cells), CD20 (B cells), and CD21 (follicular dendritic cells).

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The primary outcome measure was the presence or absence of a germinal centre. The secondary outcome was evaluation of any correlation between the degree of fibrosis and germinal centres. Fisher's exact test was used for univariate analysis.

RESULTS AND LIMITATIONS

In six patients, ectopic germinal centres were found. In ten patients, there was no inflammation at all. There was no correlation found between the degree of fibrosis and the abundance of immunohistochemically detected immune cells.

CONCLUSIONS

Ectopic germinal centres, with B and T cells as well as follicular dendritic cell networks, do exist in urethral stricture disease. This finding may open up for novel research avenues on the possibility of adopting immunological treatments for urethral stricture disease.

PATIENT SUMMARY

In patients with a narrowing of the urethra due to any kind of trauma, we looked for the presence of centres of immunological reaction in urethral tissue. We identified these immunological centres (also called germinal centres) in some patients. This intriguing finding suggests that immunological treatments may have potential for men with scar tissue in a narrowed urethra.

Corneal endothelium tissue engineering: An evolution of signaling molecules, cells, and scaffolds toward 3D bioprinting and cell sheets

Cornea is an avascular and transparent tissue that focuses light on retina. Cornea is supported by the corneal-endothelial layer through regulation of hydration homeostasis. Restoring vision in patients afflicted with corneal endothelium dysfunction-mediated blindness most often requires corneal transplantation (CT), which faces considerable constrictions due to donor limitations. An emerging alternative to CT is corneal endothelium tissue engineering (CETE), which involves utilizing scaffold-based methods and scaffold-free strategies. The innovative scaffold-free method is cell sheet engineering, which typically generates cell layers surrounded by an intact extracellular matrix, exhibiting tunable release from the stimuli-responsive surface. In some studies, scaffold-based or scaffold-free technologies have been reported to achieve promising outcomes. However, yet some issues exist in translating CETE from bench to clinical practice. In this review, we compare different corneal endothelium regeneration methods and elaborate on the application of multiple cell types (stem cells, corneal endothelial cells, and endothelial precursors), signaling molecules (growth factors, cytokines, chemical compounds, and small RNAs), and natural and synthetic scaffolds for CETE. Furthermore, we discuss the importance of three-dimensional bioprinting strategies and simulation of Descemet's membrane by biomimetic topography. Finally, we dissected the recent advances, applications, and prospects of cell sheet engineering for CETE.

European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction

INTRODUCTION

Rodent animal models are currently the most used in vivo model in translational studies looking into the pathophysiology of erectile dysfunction after nerve-sparing radical prostatectomy.

AIM

This European Society for Sexual Medicine (ESSM) statement aims to guide scientists toward utilization of the rodent model in an appropriate, timely, and proficient fashion.

METHODS

MEDLINE and EMBASE databases were searched for basic science studies, using a rodent animal model, looking into the consequence of pelvic nerve injury on erectile function.

MAIN OUTCOME MEASURES

The authors present a consensus on how to best perform experiments with this rodent model, the details of the technique, and highlight possible pitfalls.

RESULTS

Owing to the specific issue-basic science-Oxford 2011 Levels of Evidence criteria cannot be applied. However, ESSM statements on this topic will be provided in which we summarize the ESSM position on various aspects of the model such as the use of the Animal Research Reporting In Vivo Experiments guideline and the of common range parameter for nerve stimulation. We also highlighted the translational limits of the model.

CONCLUSION

The following statements were formulated as a suggestive guidance for scientists using the cavernous nerve injury model. With this, we hope to standardize and further improve the quality of research in this field. It must be noted that this model has its limitations. Weyne E, Ilg MM, Cakir OO, et al. European Society for Sexual Medicine Consensus Statement on the Use of the Cavernous Nerve Injury Rodent Model to Study Postradical Prostatectomy Erectile Dysfunction. Sex Med 2020;8:327-337.

Recent advances in managing Peyronie's disease

Treating men with Peyronie's disease remains a challenging problem facing clinicians working across urology and sexual medicine fields. Patients can often be left disappointed by current treatment paradigms, and an overall lack of suitable molecular targets has limited the options for novel, effective medical therapy. Managing men with Peyronie's disease often involves careful counselling alongside multifaceted and possible combination treatments to help improve symptoms whilst ameliorating potential side effects of therapy. We review the latest medical literature and evidence in the contemporary management of Peyronie's disease.

Evolving therapies for Peyronie's disease: how can we work towards new drugs?

Peyronie’s disease (PD) is an idiopathic chronic fibrotic disease that causes a penile curvature (PC), subsequent erectile dysfunction (ED) and impaired sexual intercourse in patients. As of yet, there are no reliable non-surgical treatment options available. Intralesional injection with collagenase Clostridum Histolyticum has been FDA approved since 2013, but post-approval studies have not been unanimously positive. Moreover, it renders a curvature improvement of only 30% on average, usually still requiring surgical intervention to remedy PC. Therefore, there is a need for drugs which could prevent surgery altogether. Development of new drugs can either be through a target-based or phenotypic assay-based approach. The current in vivo model for PD is dependent on treatment of primary PD-derived fibroblasts with transforming growth factor-β1. Moreover, despite the existence of a genetic in vivo PD model, it does not allow for drug screening or testing. While some advances have been made in the past few years, new in vivo and in vivo systems and well-designed studies are urgently needed for the non-surgical treatment of PD.

MicroRNA-145 engineered bone marrow-derived mesenchymal stem cells alleviated erectile dysfunction in aged rats

Background

Aging is one of the dominant factors contributing to erectile dysfunction (ED), and effective treatments for age-associated ED are urgently demanded. In this study, the therapeutic efficiency of bone marrow-derived mesenchymal stem cells (BMSCs) overexpressing microRNA-145 (miR-145) was evaluated in ED.

Methods

Sixty male Sprague-Dawley rats (24 months old) were randomly divided into 4 treatment groups (n = 15/group): PBS (control), BMSCs, BMSCs transfected with a blank vector (vector-BMSCs), and BMSCs transfected with a lentivirus overexpressing miR-145 (OE-miR-145-BMSCs). Fourteen days after transplantation of BMSCs, erectile function was evaluated by measuring intra-cavernous pressure (ICP) and mean arterial pressure (MAP). Subsequently, penile erectile tissues were harvested and subjected to Masson staining, qRT-PCR, immunofluorescence staining, dual luciferase assay, and Western blot analysis.

Results

Fourteen days after transplantation, the ICP/MAP was 0.79 ± 0.05 in the OE-miR-145-BMSC group, 0.61 ± 0.06 in the BMSC group, 0.57 ± 0.06 in the vector-BMSC group, and 0.3 ± 0.01 in the PBS group. Treatment with OE-miR-145-BMSCs significantly improved ED (P < 0.05), and the treatment increased the smooth muscle content in the penis tissues of ED rats (P < 0.05). In the OE-miR-145-BMSC group, the expression levels of α-SMA, desmin, and SM-MHC were higher than they were in the other ED groups (P < 0.05). In addition, the levels of collagen 1, MMP2, and p-Smad2 in the BMSC-treated group, especially in the OE-miR-145-BMSC group, were lower than those in the control group (P < 0.05).

Conclusions

MicroRNA-145 engineered BMSCs effectively attenuate age-related ED. Transplantation of miR-145-overexpressing BMSCs may provide a promising novel avenue for age-associated ED therapy.

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.

Stem-cell regenerative medicine as applied to the penis

PURPOSE OF REVIEW

Tissue engineering and regenerative medicine has emerged as a new scientific interdisciplinary field focusing on developing new strategies to repair or recreate tissues and organs. This review gathers findings on erectile dysfunction and, Peyronie's disease from recent preclinical and clinical studies under heading of stem-cell regenerative medicine.

RECENT FINDINGS

Over the last 2 years, preclinical studies on rat models demonstrated the tangible beneficial role of stem cells and stromal vascular fraction in the context of preventing fibrosis and restoring erectile function in different animal models of Erectile dysfunction and Peyronie's disease. There are not solid evidences in the clinical settings.

SUMMARY

Large randomized, double blind clinical trials are needed to prove the efficacy of stem-cell therapy on human patients. Owing to the lack of solid evidences, the stem-cell therapy should be only administrated in a clinical research setting.

Intratunical injection of autologous adipose stromal vascular fraction reduces collagen III expression in a rat model of chronic penile fibrosis

Previous studies have shown that the injection of adipose stem cells and stromal vascular fraction(SVF) into the tunica albuginea (TA) during the inflammatory phase in a rat model of Peyronie's disease(PD) prevented the development of TA fibrosis. Our aim was to investigate whether local injection of SVF can reduce established fibrosis in a rat model of chronic phase of PD. Eighteen-male 12-wk-old Sprague-Dawley rats were divided in three equal groups: sham, PD without treatment (PD) and PD treated with SVF(PD-SVF). Sham rats underwent 2 injections of vehicle into the TA one month apart. PD rats underwent TGF-β1 injection and injection of vehicle one month later. PD-SVF rats underwent TGF-β1 injection followed by SVF (1-million cells) one month later. One month after the last treatment, the animals, n = 6 rats per group, underwent measurement of intracorporal and mean arterial pressure during electrostimulation of the cavernous nerve. Following euthanasia, penises were harvested for in-vitro study. Erectile function was not statistically significantly different between groups. PD animals developed subtunical areas of fibrosis and elastosis with upregulation of collagen III protein. These fibrotic changes were reversed after injection of SVF. We provide evidence that local injection of SVF reverses TA fibrosis in a rat model of chronic phase of PD.

What role do pharmaceuticals play in the treatment of Peyronie's disease and is there a need for new emerging drugs?

INTRODUCTION

Finding novel medical treatment for Peyronie's disease (PD) has suffered from similar limitations and difficulties as other fibrotic diseases.Areas covered: Underlying fibrosis, there is a vastly complex intertwining of several pathways. Focusing on a single target during antifibrotic drug development has not led to the development of many efficacious drugs, especially in PD. Inhibiting one cog in this large machinery usually leads to activation of compensatory mechanisms.Expert opinion: Novel strategies in drug discovery such as phenotypical drug screening and gene expression profiling technologies could provide a solution for this impasse.