Penile Elastography Versus Penile Duplex Ultrasonography in Diagnosing Non-Responders to Intracavernosal Injection: A Prospective Cohort Study

OBJECTIVES

The current study aims to investigate the value of penile elastography in assessing the fibrotic changes in the corpora cavernosa.

PATIENTS AND METHODS

Eighty participants were included in the study. These were divided into two equal groups: a study group (group 1) included patients with ED who did not respond to intracavernosal injection (ICI), and an age-matched control group (group 2) included age-matched subjects with normal erection. All subjects answered an International Index of Erectile Function-5 (IIEF-5) questionnaire. The first group was evaluated by two ICI trials of 1 mL Quadmix, each took place 1 week apart, followed by a color duplex/Doppler ultrasonography (CDDU) scan using also a 1 mL Quadmix. All the above was done a week before the penile shear wave elastography (SWE) scan. It comprised a 12-section scan of both corpora cavernosa. Each corpus was scanned in three different segments (proximal, mid-shaft, and distal), and in both longitudinal and transverse axes.

RESULTS

Comparisons of the laboratory data were non-significant, apart from the glycosylated hemoglobin which proved significant (P value <.001) in both groups. Also, the IIEF-5 scores were significantly lower in the study group (P value <.001). Significantly higher SWE readings (indicating higher fibrotic) were found in the study group compared with the control group in almost all of the scanned segments and their combinations (P value <.05).

CONCLUSION

SWE can effectively assess the fibrotic changes occurring in the corpora cavernosa. Hence, SWE could be utilized as a modality that helps diagnose patients with ED.

Stem cell therapy for erectile dysfunction: a systematic review

INTRODUCTION

Erectile dysfunction (ED) is a common condition that negatively affects men's quality of life. It can have various causes, including psychological, vascular, and neurologic factors. Existing treatments for ED mainly focus on symptom relief rather than addressing the underlying cause. Stem cells (SCs) have shown potential as a therapeutic approach for ED due to their anti-inflammatory properties.

OBJECTIVES

This systematic review aims to assess the current status of trials and determine the potential impact of SCs on male sexual health.

METHODS

A comprehensive search strategy was employed to gather relevant articles from 6 electronic databases. The search included articles published until March 2023. The reference lists of articles were manually reviewed to identify additional studies of relevance. The eligibility criteria for inclusion in the analysis focused on clinical trials involving humans that evaluated the safety and efficacy of SC therapy for ED. Exclusion criteria encompassed case reports, case series, abstracts, reviews, and editorials, as well as studies involving animals or SC derivatives. Data extraction was performed via a standardized form with a focus on erectile outcomes.

RESULTS

A total of 2847 articles were initially identified; 18 were included in the final analysis. These studies involved 373 patients with ED and various underlying medical conditions. Multiple types of SC were utilized in the treatment of ED: mesenchymal SCs, placental matrix-derived mesenchymal SCs, mesenchymal SC-derived exosomes, adipose-derived SCs, bone marrow-derived mononuclear SCs, and umbilical cord blood SCs.

CONCLUSION

SC therapy shows promise as an innovative and safe treatment for organic ED. However, the lack of standardized techniques and controlled groups in many studies hampers the ability to evaluate and compare trials.

Erectile response profiles of men using PDE5 inhibitors combined with intracavernosal injections as part of a penile rehabilitation program after radical prostatectomy

BACKGROUND

Phosphodiesterase type 5 (PDE5) inhibitor labeling states that these agents should not be used in conjunction with other erectogenic medications for fear of priapism occurring.

AIM

We explored the risk of priapism and prolonged erections in men in our post-radical prostatectomy (RP) penile injection program who were using regular PDE5 inhibitor and intracavernosal injections (ICIs) as part of their rehabilitation program.

METHODS

The study cohort included men on penile injection therapy who (1) were taking tadalafil 5 mg daily or taking sildenafil 25 mg on noninjection days, (2) had an RP, (3) were using their respective PDE5 inhibitor regularly at the time of penile injection training, and (4) complied with the program instructions regarding penile injection use. Demographics, comorbidity details, PDE5 inhibitor dose and utilization, and injection dose and utilization data were collected. All patients underwent in-office injection training and used trimix (papaverine/phentolamine/prostaglandin E1) as the intracavernosal medication.

OUTCOMES

Priapism was defined as a patient self-reported penetration hardness erection ≥4 hours in duration, while prolonged erection was defined as a penetration hardness erection lasting ≥2 hours.

RESULTS

A total of 112 tadalafil users and 364 sildenafil users were compared. Mean age and duration post-RP were 62 ± 14 years and 5.2 ± 12 months, respectively, and there was no difference between tadalafil and sildenafil groups. The mean trimix dose was tadalafil 24 ± 24 units and sildenafil 31 ± 37 units (P < .05). Priapism occurred in 2 (1.7%) of 112 tadalafil users and 5 (1.4%) of 364 sildenafil users (P = .47). Excluding those men experiencing priapism on any occasion, those with any reported penetration hardness erection lasting ≥2 hours were 7 (6.3%) of 112 tadalafil users and 12 (3.3%) of 364 sildenafil users (P < .01). A total of 53% of these prolonged erections occurred within the first 6 injections at home (no difference between tadalafil and sildenafil groups).

CLINICAL IMPLICATIONS

We emphasize the need for continued monitoring and education on proper injection techniques to minimize the risk of adverse events in ICI and PDE5 inhibitor combination therapy.

STRENGTHS & LIMITATIONS

This study has a relatively large patient population with a considerable follow-up time. Additionally, the rigorous training, education, and monitoring of the participants, as well as the use of formal definitions for priapism and prolonged erections, enhances the accuracy and reliability of the results. However, there are some limitations, such as social desirability, confounding factors, and recall bias.

CONCLUSION

There is no significant difference in the incidence of priapism in an ICI program in which men combine ICI with tadalafil or sildenafil. However, tadalafil patients had a higher rate of prolonged erections, which was found to occur mostly early during the titration phase.

Current status of intracavernosal injection therapy in erectile dysfunction

INTRODUCTION

Erectile dysfunction (ED) is defined as the inability to attain and/or maintain a penile erection. The first introduction of intracavernosal injection (ICI) for the treatment of erectile failure was in 1982 by Virag who reported the positive effects of papaverine on erectile tissue, followed by Brindley concurrently conducting research on ICI therapy with alpha-blockade. ICI remains a viable option for the treatment of ED, even after FDA approval of phosphodiesterase type 5 inhibitors in 1998. The American Urological Association (AUA) and the European Association of Urology (EAU) both recommend ICI as a second-line therapy for the treatment of ED. We herein provide an overview of the current state of ICI therapy for the treatment of ED.

AREAS COVERED

We performed a literature review from 1977-2022, using PubMed and the current AUA and EAU guidelines to discuss the current state of ICI for the treatment of ED.

EXPERT OPINION

Although other oral agents are considered first line for the treatment of ED, the current guidelines and literature demonstrate that ICI is a safe and effective option for patients; however, careful patient selection and counseling should be performed to maximize the effectiveness and safety of this ED treatment.

Management of male erectile dysfunction: From the past to the future

Erectile dysfunction is a common disease of the male reproductive system, which seriously affects the life quality of patients and their partners. At present, erectile dysfunction is considered as a social-psychological-physiological disease with complex etiology and various treatment methods. Oral PDE5I is the first-line treatment for erectile dysfunction with the advantages of high safety, good effect and non-invasiveness. But intracavernosal injection, hormonal replacement therapy, vacuum erection device, penile prosthesis implantation can also be alternative treatments for patients have organic erectile dysfunction or tolerance to PDE5I. With the rapid development of technologies, some new methods, such as low-intensity extracorporeal shock wave and stem cell injection therapy can even repair the organic damage of the corpora cavernosa. These are important directions for the treatment of male erectile dysfunction in the future. In this mini-review, we will introduce these therapies in detail.

Penile Rehabilitation and Treatment Options for Erectile Dysfunction Following Radical Prostatectomy and Radiotherapy: A Systematic Review

After radical prostatectomy (RP) or radiotherapy (RT) for prostate cancer, erectile dysfunction (ED) is the main complication next to urinary incontinence, affecting quality of life. The pathophysiology of ED after these treatments is believed to include neuropraxia causing reduced oxygenation and structural changes of the tissue in the corpora cavernosa. Next to the option of sparing the nerves during RP, research has been focusing on methods for penile rehabilitation after RP and RT, since it occurs often, even after nerve-sparing techniques were used. In animal studies, the use of phosphodiesterase type 5 inhibitors (PDE5i) after cavernous nerve damage is supported, but results in human studies are contradictory. Non-medical treatment options such as vacuum device therapy, hyperbaric oxygen therapy, yoga, aerobic, or pelvic floor training may be helpful, but evidence is scarce. Clear guidelines for penile rehabilitation are not yet available. However, care and support for ED after RP and RT is highly demanded by a large group of patients, so measures have to be taken even though the evidence is not strong yet. In this systematic review, an overview of the literature for penile rehabilitation and treatment options for ED after RP and RT is provided, using only randomized controlled trials (RCT).

Administration of secretome from human placental stem cell-conditioned media improves recovery of erectile function in the pelvic neurovascular injury model

Human placental stem cells (PSCs) enhance histological and functional recovery in a rodent erectile dysfunction (ED) model. We tested the hypothesis that bioactive factors secreted by PSC (i.e., the secretome) mediate functional recovery and that acellular-conditioned media (CM) from PSC culture (PSC-CM) could be used independently to facilitate functional and histological recovery. To identify factors relative to efficacy of PSC, a comparison of CM from PSC and three additional human stem cell populations was performed. CM from human PSC, amniotic fluid stem cells (AFSCs), adipose-derived stem cells (ADSC), and human umbilical vein endothelial cells (HUVECs) was assayed using a semi-quantitative human cytokine antibody array. Male rats, after surgically created ED by neurovascular injury, were randomly divided into four groups: vehicle control (phosphate-buffered saline [PBS]), PSC, PSC-CM, and serum-free media control (SFM) as control. Functional data on intracorporal and mean arterial pressure were obtained, and histological architecture was examined 6 weeks after single injection. PSCs were found to secrete at least 27 cytokines and growth factors at a significantly higher level than the other three cell types. Either single injection of PSC-CM or PSC significantly improved erectile functional recovery and histological architecture compared with SFM or PBS. Injection of the secretome isolated from human PSC improves erectile functional recovery and histological structure in a rat model of neurovascular injury-induced ED. Further characterization of the unique protein expression within the PSC-CM may help to identify the potential for a novel injectable cell-free therapeutic for applicable patients.

Revisiting the Regenerative Therapeutic Advances Towards Erectile Dysfunction

Erectile dysfunction (ED) is an inability to attain or maintain adequate penile erection for successful vaginal intercourse, leading to sexual and relationship dissatisfaction. To combat ED, various surgical and non-surgical approaches have been developed in the past to restore erectile functions. These therapeutic interventions exhibit significant impact in providing relief to patients; however, due to their associated adverse effects and lack of long-term efficacy, newer modalities such as regenerative therapeutics have gained attention due to their safe and prolonged efficacy. Stem cells and platelet-derived biomaterials contained in platelet-rich plasma (PRP) are thriving as some of the major therapeutic regenerative agents. In recent years, various preclinical and clinical studies have evaluated the individual, as well as combined of stem cells and PRP to restore erectile function. Being rich in growth factors, chemokines, and angiogenic factors, both stem cells and PRP play a crucial role in regenerating nerve cells, myelination of axons, homing and migration of progenitor cells, and anti-fibrosis and anti-apoptosis of damaged cavernous nerve in corporal tissues. Further, platelet-derived biomaterials have been proven to be a biological supplement for enhancing the proliferative and differentiation potential of stem cells towards neurogenic fate. Therefore, this article comprehensively analyzes the progresses of these regenerative therapies for ED.

Is topical alprostadil an usable and reliable alternative to intracavernous injection for penile dynamic duplex ultrasonography?

No study has yet been done to evaluate topical alprostadil as a less invasive alternative vasoactive agent for Penile Dynamic Duplex Ultrasonography (PDDU) in the diagnosis of erectile dysfunction. The main aim of our study was to evaluate the usability and reliability of topical alprostadil for PDDU compared with standard intracavernous injection. A further objective was to determine the patients' preference between these two different approaches. During session A, patients received injection while during session B, they received topical alprostadil. Each patient underwent both sessions, 1 week apart from the other. A total of 80 patients were enrolled. After 20 min from drug administration, no significant difference was found between the two procedures in terms of peak systolic velocity and end-diastolic velocity, while Erection Hardness Score was significantly higher with injection. Patients reported less pain/discomfort during the procedure in case of topical alprostadil use and an overall preference towards this examination modality. Topical alprostadil could represent a usable and reliable alternative to intracavernous injection for PDDU, with less discomfort and greater preference by patients.

A Review of Current and Emerging Therapeutic Options for Erectile Dysfunction

Contemporary treatment algorithms for erectile dysfunction (ED) involve the use of medical therapies such as phosphodiesterase type 5 (PDE5) inhibitors and intracavernosal injection therapy of vasoactive agents, as well as vacuum erection devices and penile prosthesis implants in medically refractory cases. However, the current therapeutic options only address the symptoms of ED and not the underlying pathogenesis that results in ED. Newer and novel ED therapies aspire to reverse ED conditions by preventing cavernosal fibrosis, promoting endothelial revascularization and modulating various neuro-hormonal pathways. Regenerative therapeutic strategies such as low-intensity shock wave, gene and cellular-based therapies, and penile transplants are designed to improve penile hemodynamics and revitalize the cavernosal smooth muscle to mitigate and/or reverse underlying ED. This state-of-art article evaluates current and emerging therapeutic options for ED.

Penile Rehabilitation: The "Up"-date

Purpose of Review

The purpose of this review is to review the penile rehabilitation literature published since the beginning of 2017. Specific emphasis was placed on determining how the new findings increase our understanding of the mechanisms leading to recovery of erectile function after pelvic surgery and to identify potential focus areas for future studies.

Recent Findings

A meta-analysis of penile rehabilitation after prostatectomy was published in early 2017 reporting that PDE-5 inhibitors, intracavernosal injection (ICI) therapy and vacuum erection devices (VED) improved erectile function; however, the benefit was not observed after a washout period. Preclinical studies have identified potential regenerative therapies after cavernous nerve injury.

Summary

While significant methodological challenges remain, recent literature suggests benefits to starting penile rehabilitation immediately after surgery, but not extending past 1 year post-operatively. The cost-benefit ratio of penile rehabilitation remains unclear; however, decreasing costs of PDE-5 inhibitors as well as improvements in characterizing post-surgical erectile dysfunction may help to personalize penile rehabilitation, improve outcomes and improve the cost-benefit ratio. Better and more consistent trial design is needed to develop the optimal regimen(s) for restoring sexual function in men. Finally, future studies to translate promising preclinical regeneration therapies to humans are also needed.

Engineered Mesenchymal Stem Cells Expressing Stromal Cell-derived Factor-1 Improve Erectile Dysfunction in Streptozotocin-Induced Diabetic Rats

Effective therapies for erectile dysfunction (ED) associated with diabetes mellitus (DM) are needed. In this study, the effects of stromal cell-derived factor-1 (SDF-1)-expressing engineered mesenchymal stem cells (SDF-1 eMSCs) and the relevant mechanisms in the corpus cavernosum of a streptozotocin (STZ)-induced DM ED rat model were evaluated. In a randomized controlled trial, Sprague–Dawley (SD) rats (n = 48) were divided into four groups (n = 12/group): Normal (control), DM ED (diabetes induced by STZ), DM ED + BM-MSC (treated with bone marrow [BM]-derived MSCs), and DM ED + SDF-1 eMSC (treated with SDF-1-expressing BM-MSCs). After four weeks, intracavernosal pressure (ICP), an indicator of erectile function, was 0.75 ± 0.07 in the normal group, 0.27 ± 0.08 in the DM ED group, 0.42 ± 0.11 in the DM ED + BM-MSC group, and 0.58 ± 0.11 in the DM ED + SDF-1 eMSC group. BM-MSCs, especially SDF-1 eMSCs, improved ED (p < 0.05). SDF-1 eMSC treatment improved the smooth muscle content in the corpus cavernosum (p < 0.05). As SDF-1 expression increased, ED recovery improved. In the SDF-1 eMSC group, levels of neuronal nitric oxide synthase (nNOS) and phosphorylated endothelial NOS (p-eNOS) were higher than those in other groups (p < 0.05). In addition, high stromal cell-derived factor-1 (SDF-1) expression was associated with increased vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in DM ED rats (p < 0.05). Higher levels of phosphorylated protein kinase B (p-AKT)/protein kinase B (AKT) (p < 0.05) and B-cell lymphoma-2 (Bcl-2) and lower levels of the apoptosis factors Bcl2-associated x (Bax) and caspase-3 were observed in the MSC-treated group than in the DM ED group (p < 0.05). SDF-1 eMSCs showed beneficial effects on recovery from erectile function.

Effects of insulin-like growth factor-1 on the relaxation responses of the cavernous smooth muscle from aged rats

OBJECTIVE

The aim of this study was determine whether intracavernosal injection (ICI) of insulin-like growth factor-1 (IGF-1) protein can improve corpus cavernosal smooth muscle relaxation in aging rats.

MATERIALS AND METHODS

Ten young (4-month-old) and 30 old (24-month-old) Sprague-Dawley male rats were enrolled in the study. The old rats were divided into three groups: vehicle-only (n = 10), IGF-1 1 µg/kg (n = 10) and IGF-1 10 µg/kg treatment groups (n = 10). After 4 weeks of single IGF-1 injection treatment, strips of corporal tissue were precontracted with phenylephrine, and dose-response curves were generated to evaluate endothelial-dependent [acetylcholine (ACh)], endothelial-independent [sodium nitroprusside (SNP)] and electrical field stimulation (EFS) vasoreactivity. The changes in percentage of cavernosal smooth muscle and the concentration of nitric oxide (NO) in penile tissue were also evaluated.

RESULTS

After IGF-1 treatment, the vasoreactivity was significantly improved in both the 1 µg/kg and the 10 µg/kg treatment groups compared with the vehicle-only group at 4 weeks in response to ACh, SNP and EFS (all p < 0.05). The percentage of cavernosal smooth muscle was increased in the IGF-1 treatment groups. The NO concentrations were increased after IGF-1 treatment.

CONCLUSIONS

These data demonstrate that ICI of IGF-1 can improve vasoreactivity via endothelium-dependent and endothelial-independent mechanisms in the corpus cavernosum of the aging rat.

A study of the possible effects of repeated intracorporeal self-injection of vasoactive drugs in patients with elevated end diastolic velocity during pharmacopenile duplex ultrasonography

Introduction

The aim of the work is to evaluate the effect of repeated intracavernosal self-injection of vasoactive drugs in patients with elevated End Diastolic Velocity (>5 cm/sec) during pharmacopenile duplex ultrasonography (PPDU).

Methods

Duplex evaluation was performed to the patients on self-injection therapy for comparison of end diastolic velocity and resistive index before and after completing the eight doses of IC self-injection.

Results

After the 8 trials of home therapy, 21 (52.5%) patients showed improvement in the duplex parameters regarding the end diastolic velocity, ten of them showed improvement in the EDV to the level of <5 cm/sec. The effect of different factors that may contribute to the improvement in EDV to <5 cm/sec are shown in the table 2. Age was the only predictive factor for successful response to home therapy intracavernous injection (ICI). Improvement in erectile response was assessed before and after the course of the therapy. Erection response to ICI during penile duplex improved in only six patients (E4 & E4-5)) to the point that it was sufficient for satisfactory sexual performance, 3 of them (7.5%) regained spontaneous erection and stopped using ICI (table 3). The IIEF score was 10.6 ±2.8 before the home therapy and it became 14 ±3.9 one month after completing the treatment course (P value <0.001).

Conclusions

Early rehabilitation of the patients with venous leakage ED using ICI may help to regain normal erection and avoid unnecessary penile prosthesis surgeries.