Amniotic therapeutic biomaterials in urology: current and future applications

The Effect of Multilayered Electrospun PLLA Nanofibers Coated with Human Amnion or Bladder ECM Proteins on Epithelialization and Smooth Muscle Regeneration in the Rabbit Bladder

Nanofibrous scaffolds have attracted much attention in bladder reconstruction approaches due to their excellent mechanical properties. In addition, their biological properties can be improved by combination with biological materials. Taking into account the advantages of nanofibrous scaffolds and decellularized extracellular matrix (dECM) in tissue engineering, scaffolds of poly-L-lactic acid (PLLA) coated with decellularized human amnion membrane (hAM) or sheep bladder (SB)-derived ECM proteins are developed (amECM-coated PLLA and sbECM-coated PLLA, respectively). The bladder regenerative potential of modified electrospun PLLA scaffolds is investigated in rabbits. The presence of ECM proteins is confirmed on the nanofibers' surface. Coating the surface of the PLLA nanofibers improves cell adhesion and proliferation. Histological and immunohistochemical evaluations show that rabbits subjected to cystoplasty with a multilayered PLLA scaffold show de novo formation and maturation of the multilayered urothelial layer. However, smooth muscle bundles (myosin heavy chain [MHC] and α-smooth muscle actin [α-SMA] positive) are detected only in ECM-coated PLLA groups. All groups show no evidence of a diverticulumor fistula in the urinary bladder. These results suggest that the biofunctionalization of electrospun PLLA nanofibers with ECM proteins can be a promising option for bladder tissue engineering. Furthermore, hAM can also replace animal-sourced ECM proteins in bladder tissue regeneration approaches.

Low-dose prednisone is an effective rescue for deteriorating semen parameters following vasovasostomy

OBJECTIVE

This retrospective study aimed to evaluate the effectiveness of low-dose prednisone as a rescue therapy for patients with deteriorating semen parameters following vasovasostomy.

MATERIALS AND METHODS

Electronic medical records were queried at the University of Miami with documented CPT code 55400 (Bilateral Vasovasostomy) between January 2016 and April 2023. Records were then reviewed to identify patients who demonstrated ≥50% decrease in semen parameters, specifically sperm concentration, motility and total motile sperm count. Patients who were treated with 6 weeks of low-dose prednisone were identified, and baseline semen parameters and subsequent changes after prednisone therapy were assessed. A Mann-Whitney U Test was used to compare semen parameter changes before and after prednisone. Adverse effects associated with prednisone were monitored.

RESULTS

A total of 8 patients were identified with deteriorating semen parameters who were treated with 6 weeks of low-dose prednisone. Following prednisone therapy, all patients demonstrated improvements in total motile sperm count (TMSC), with a median improvement of 6 million. The median relative improvement in TMSC was 433%. Sperm concentration and motility also improved compared to post-operative baseline. No adverse effects were reported during the treatment period.

CONCLUSIONS

Low-dose prednisone therapy appears to be a safe and effective intervention for managing deteriorating semen parameters following VV. The observed improvements in TMSC suggest the potential of prednisone to rescue patients with delayed failure after VV. Further research with larger sample sizes is warranted to confirm the safety and efficacy of low-dose prednisone as a rescue therapy in this specific patient population. Optimizing VV outcomes is crucial in male infertility, and further exploration of steroid therapy and innovative biotechnologies is warranted.

Early three-month report of amniotic bladder therapy in patients with interstitial cystitis/bladder pain syndrome

BACKGROUND

Interstitial cystitis/bladder pain syndrome (IC/BPS) is characterized by symptomatic frequency and urgency, as well as chronic pelvic pain. Disruption of the urothelial barrier is closely associated with IC/BPS. As amniotic membranes (AM) offer capabilities of wound healing in many other fields of medicine, likewise amniotic bladder therapy (ABT) may offer capability of urothelial healing in IC/BPS.

METHODS

Under general anesthesia, 10 consecutive IC/BPS patients received intra-detrusor injections of 100 mg micronized AM (Clarix Flo) diluted in 10 ml 0.9% preservative-free sodium chloride. Clinical evaluation and questionnaires (Interstitial Cystitis Symptom Index (ICSI), Interstitial Cystitis Problem Index (ICPI), Bladder Pain/ Interstitial Cystitis Symptom Score (BPIC-SS), Overactive Bladder Assessment Tool, and SF-12 Health Survey) were repeated at pre-op and 2, 4, 8 and 12 weeks post-op.

RESULTS

Ten females (47.4 ± 14.4 years) who had recalcitrant IC/BPS for 7.8 years (5.2-12.1 years) received injection of micronized AM uneventful in all cases. After treatment, voiding symptoms and bladder pain significantly improved from pre-injection to 3 months. BPIC-SS significantly decreased from 37.4 ± 0.70 at baseline to 12.2 ± 2.90 at 3 months (p < 0.001). This corresponded to a significant improvement in their overall physical and mental quality of life. No adverse events occurred related to micronized AM injections, such as UTIs or acute urinary retention.

CONCLUSION

ABT could be an innovative treatment option for IC/BPS patients in terms of improving clinical symptoms based on preliminary outcomes at 3 months. Further studies are warranted to confirm the usefulness of ABT in patients with IC/BPS and to determine the duration of the effect.

Recent Trends and Advances in Anterior Urethroplasty

While patient preference often helps guide treatment decisions, poor long-term success combined with cumulative risk of repeat endoscopic treatments and the complications innately associated with urethral stricture emphasize that urethroplasty is most often the best choice for successful treatment in the long-term. This has led to the need to better refine urethroplasty techniques and optimize patient outcomes. Urethroplasty has now largely transitioned to a day-surgery procedure in the majority of centers. Some evidence suggests that avoiding urethral transection and/or avoiding overzealous urethral mobilization may lead to a reduction in post-operative sexual dysfunction. The trend toward single stage penile urethroplasty with buccal mucosal grafts likely minimizes patient morbidity without compromising urethroplasty success. For urethroplasty success to further improve particularly in patients at high risk for stricture recurrence, the synergistic potential of combining wound healing enhancing agents with evolving tissue-engineering represents an exciting future opportunity in the quest to perfect urethroplasty outcomes.

Placental Tissues as Biomaterials in Regenerative Medicine

Placental tissues encompass all the tissues which support fetal development, including the placenta, placental membrane, umbilical cord, and amniotic fluid. Since the 1990s there has been renewed interest in the use of these tissues as a raw material for regenerative medicine applications. Placental tissues have been extensively studied for their potential contribution to tissue repair applications. Studies have attributed their efficacy in augmenting the healing process to the extracellular matrix scaffolds rich in collagens, glycosaminoglycans, and proteoglycans, as well as the presence of cytokines within the tissues that have been shown to stimulate re-epithelialization, promote angiogenesis, and aid in the reduction of inflammation and scarring. The compositions and properties of all birth tissues give them the potential to be valuable biomaterials for the development of new regenerative therapies. Herein, the development and compositions of each of these tissues are reviewed, with focus on the structural and signaling components that are relevant to medical applications. This review also explores current configurations and recent innovations in the use of placental tissues as biomaterials in regenerative medicine.

A comprehensive review on methods for promotion of mechanical features and biodegradation rate in amniotic membrane scaffolds

Amniotic membrane (AM) is a biological tissue that surrounds the fetus in the mother's womb. It has pluripotent cells, immune modulators, collagen, cytokines with anti-fibrotic and anti-inflammatory effect, matrix proteins, and growth factors. In spite of the biological characteristics, some results have been released in preventing the adhesion on traumatized surfaces. Application of the AM as a scaffold is limited due to its low biomechanical resistance and rapid biodegradation. Therefore, for using the AM during surgery, its modification by different methods such as cross-linking of the membrane collagen is necessary, because the cross-linking is an effective way to reduce the rate of biodegradation of the biological materials. In addition, their cross-linking is likely an efficient way to increase the tensile properties of the material, so that they can be easily handled or sutured. In this regard, various methods related to cross-linking of the AM subsuming the composite materials, physical cross-linking, and chemical cross-linking with the glutraldehyde, carbodiimide, genipin, aluminum sulfate, etc. are reviewed along with its advantages and disadvantages in the current work.

Applications of Human Amniotic Membrane for Tissue Engineering

An important component of tissue engineering (TE) is the supporting matrix upon which cells and tissues grow, also known as the scaffold. Scaffolds must easily integrate with host tissue and provide an excellent environment for cell growth and differentiation. Human amniotic membrane (hAM) is considered as a surgical waste without ethical issue, so it is a highly abundant, cost-effective, and readily available biomaterial. It has biocompatibility, low immunogenicity, adequate mechanical properties (permeability, stability, elasticity, flexibility, resorbability), and good cell adhesion. It exerts anti-inflammatory, antifibrotic, and antimutagenic properties and pain-relieving effects. It is also a source of growth factors, cytokines, and hAM cells with stem cell properties. This important source for scaffolding material has been widely studied and used in various areas of tissue repair: corneal repair, chronic wound treatment, genital reconstruction, tendon repair, microvascular reconstruction, nerve repair, and intraoral reconstruction. Depending on the targeted application, hAM has been used as a simple scaffold or seeded with various types of cells that are able to grow and differentiate. Thus, this natural biomaterial offers a wide range of applications in TE applications. Here, we review hAM properties as a biocompatible and degradable scaffold. Its use strategies (i.e., alone or combined with cells, cell seeding) and its degradation rate are also presented.

Human Amniotic Membrane: A review on tissue engineering, application, and storage

Human amniotic membrane (hAM) has been employed as scaffolding material in a wide range of tissue engineering applications, especially as a skin dressing and as a graft for corneal treatment, due to the structure of the extracellular matrix and excellent biological properties that enhance both wound healing and tissue regeneration. This review highlights recent work and current knowledge on the application of native hAM, and/or production of hAM-based tissue-engineered products to create scaffolds mimicking the structure of the native membrane to enhance the hAM performance. Moreover, an overview is presented on the available (cryo) preservation techniques for storage of native hAM and tissue-engineered products that are necessary to maintain biological functions such as angiogenesis, anti-inflammation, antifibrotic and antibacterial activity.

Use of human amniotic membrane repair of anterior urethral defect: First clinical report

OBJECTIVE

To evaluate the use of human amniotic membrane allograft to prevent urethrocutaneous fistula after tubularized incised plate repair for redo-hypospadias and anterior urethral defects.

METHODS

This pilot study included 28 patients (mean age 25.3 ± 11 years) with a history of previous failed hypospadia repair, who underwent tubularized incised plate urethroplasty in one session by the same surgical team from April 2016 to April 2019. After the reconstruction of a neourethra and proper hemostasis, a human amniotic membrane allograft - Grafting Scaffold - was used to cover the suture lines.

RESULTS

The mean follow-up time was 13.3 ± 4.5 months. Two urethrocutaneous fistulas occurred within the first 2 weeks after the surgery, one of which was caused by the infection of the surgical site. No penile torsion, urethral diverticula, meatal stenosis or glans dehiscence was reported.

CONCLUSIONS

Amniotic membrane graft provides an applicable, low-cost, feasible, biodegradable and safe second cover in redo-hypospadias repairs by tubularized incised plate technique. Its use is technically easy; it has satisfactory cosmetic outcomes and might decrease urethrocutaneous fistula formation.

The good, bad, and the ugly of regenerative therapies for erectile dysfunction

Erectile dysfunction (ED) is a common condition which reduces quality of life of both patients and their partners, and is a significant health care expense every year. Although phosphodiesterase type-5 inhibitors are the current first-line treatment for men with ED, they are limited by their on-demand dosing, intolerance, and variable efficacy in complex patient populations such as men with multiple medical comorbidities or ED after pelvic surgery. Regenerative medicine has been introduced and investigated in andrology as an encouraging strategy to restore diseased erectile tissue structure and function. Novel regenerative therapies for ED are controversial but are perceived to offer a durable and safe tissue restorative approach to act as a long-term solution to this cumbersome disease process. Here, we review platelet-rich plasma, amniotic fluid membranes, low-intensity extracorporeal shockwave therapy, and stem cell therapy as regenerative strategies to treat ED. Most of these approaches have preclinical and occasionally clinical data to support their ongoing investigation; however, none of these treatments are currently supported for use in ED patients outside of clinical trials.

Placental membrane grafts for urethral replacement in a rabbit model: a pilot study

PURPOSE

Several graft materials are available for use in the treatment of urethral stricture disease. Placental membrane is being used in a variety of settings as a graft in wound healing and tissue repair. We aim to evaluate the effect of implanting decellularized human placental membrane into rabbit urethras.

METHODS

Dorsal onlay graft urethroplasty using prepared human placental membrane was performed in 10 New Zealand White rabbits (Oryctolagus cuniculus). After 3 months, the rabbits underwent cystourethroscopy to evaluate urethral patency. The rabbits were then euthanized and the urethras examined for pathological findings.

RESULTS

All urethroplasties were performed without complication. There were no observed episodes of urinary retention, infection, or renal failure. Urethral patency was achieved in all rabbits 3 months postoperatively. Urothelial replacement of the placental membrane graft was observed in all rabbits without malignant transformation.

CONCLUSION

Dorsal onlay urethroplasty using decellularized human placental membrane can safely be performed in a rabbit model. This pilot study demonstrated urothelial replacement of human placental membrane in the rabbit urethra without stricture formation. Placental membrane is a promising biomaterial for urethral reconstruction.

Application of amniotic membrane in reconstructive urology; the promising biomaterial worth further investigation

Introduction: In reconstructive urology, autologous tissues such as intestinal segments, skin, and oral mucosa are used. Due to their limitations, reconstructive urologists are waiting for a novel material, which would be suitable for urinary tract wall replacement. Human amniotic membrane (AM) is a naturally derived biomaterial with a capacity to support reepithelization and inhibit scar formation. AM has a potential to become a considerable asset for reconstructive urology, i.e., reconstruction of ureters, urinary bladder, and urethrae. Areas covered: This review aims to discuss the potential application of human AM in reconstructive urology. The environment for urinary tract healing is particularly unfavorable due to the presence of urine. Due to its fetal origin, the bioactivity of AM is orientated to induce intrinsic regeneration mechanisms and inhibit scarring. This review introduces the concept of applying human AM in reconstructive urology procedures to improve their outcomes and future tissue engineering based strategies. Expert opinion: Many fields of medicine that have accomplished translational research have proven the usefulness of AM in clinical practice. There is an urgent need for studies to be conducted on large animal models that might convincingly demonstrate the underestimated potential of AM to urologists around the world.