Functional recovery of injured cavernous nerves achieved through endogenous nerve growth factor-containing bioactive fibrous membrane.

Radical prostatectomy is a highly successful treatment for prostate cancer, among the most prevalent manifestations of the illness. Damage of the cavernous nerve (CN) during prostatectomy is the main cause of postoperative erectile dysfunction (ED). In this study, the capability of a personalized bioactive fibrous membrane to regenerate injured CN was investigated. The fibrous membrane bioactivity is conferred by the selectively bound nerve growth factor (NGF) present in the rat urine. In a rat model of bilateral CN crush, the implanted bioactive fibrous membrane induces CN regeneration and restoration of erectile function, showing a significantly increased number of smooth muscle cells and content of endothelial and neuronal nitric oxide synthases (eNOS; nNOS). In addition, the bioactive fibrous membrane promotes nerve regeneration by increasing the number of myelinated axons and nNOS-positive cells, therefore reversing the CN fibrosis found in untreated rats or rats treated with a bare fibrous membrane. Therefore, this personalized regenerative strategy could overcome the recognized drawbacks of currently available treatments for CN injuries. It may constitute an effective treatment for prostate cancer patients suffering from ED after being subject to radical prostatectomy. STATEMENT OF SIGNIFICANCE: The present work introduces a unique strategy to address post-surgical ED resulting from CN injury during pelvic surgery (e.g., radical prostatectomy, radical cystoprostatectomy, abdominoperineal resection). It comprises a bioactive and cell-free fibrous implant, customized to enhance CN recovery. Pre-clinical results in a rat model of bilateral CN crush demonstrated that the bioactive fibrous implant can effectively heal injured CN, and restore penile structure and function. This implant selectively binds NGF from patient fluids (i.e. urine) due to its functionalized surface and high surface area. Moreover, its local implantation reduces adverse side effects. This tailored regenerative approach has the potential to revolutionize the treatment of ED in prostate cancer patients following radical prostatectomy, overcoming current treatment limitations.

Surface Functionalization of Ureteral Stents-Based Polyurethane: Engineering Antibacterial Coatings.

Bacterial colonization of polyurethane (PU) ureteral stents usually leads to severe and challenging clinical complications. As such, there is an increasing demand for an effective response to this unmet medical challenge. In this study, we offer a strategy based on the functionalization of PU stents with chitosan-fatty acid (CS-FA) derivatives to prevent bacterial colonization. Three different fatty acids (FAs), namely stearic acid (SA), oleic acid (OA), and linoleic acid (LinA), were successfully grafted onto chitosan (CS) polymeric chains. Afterwards, CS-FA derivatives-based solutions were coated on the surface of PU stents. The biological performance of the modified PU stents was evaluated against the L929 cell line, confirming negligible cytotoxicity of the developed coating formulations. The antibacterial potential of coated PU stents was also evaluated against several microorganisms. The obtained data indicate that the base material already presents an adequate performance against Staphylococcus aureus, which slightly improved with the coating. However, the performance of the PU stents against Gram-negative bacteria was markedly increased with the surface functionalization approach herein used. As a result, this study reveals the potential use of CS-FA derivatives for surface functionalization of ureteral PU stents and allows for conjecture on its successful application in other biomedical devices.

A Fibrin Coating Method of Polypropylene Meshes Enables the Adhesion of Menstrual Blood-Derived Mesenchymal Stromal Cells: A New Delivery Strategy for Stem Cell-Based Therapies.

Polypropylene (PP) mesh is well-known as a gold standard of all prosthetic materials of choice for the reinforcement of soft tissues in case of hernia, organ prolapse, and urinary incontinence. The adverse effects that follow surgical mesh implantation remain an unmet medical challenge. Herein, it is outlined a new approach to allow viability and adhesion of human menstrual blood-derived mesenchymal stromal cells (MenSCs) on PP surgical meshes. A multilayered fibrin coating, based on fibrinogen and thrombin from a commercial fibrin sealant, was optimized to guarantee a homogeneous and stratified film on PP mesh. MenSCs were seeded on the optimized fibrin-coated meshes and their adhesion, viability, phenotype, gene expression, and immunomodulatory capacity were fully evaluated. This coating guaranteed MenSC viability, adhesion and did not trigger any change in their stemness and inflammatory profile. Additionally, MenSCs seeded on fibrin-coated meshes significantly decreased CD4+ and CD8+ T cell proliferation, compared to in vitro stimulated lymphocytes (p < 0.0001). Hence, the proposed fibrin coating for PP surgical meshes may allow the local administration of stromal cells and the reduction of the exacerbated inflammatory response following mesh implantation surgery. Reproducible and easy to adapt to other cell types, this method undoubtedly requires a multidisciplinary and translational approach to be improved for future clinical uses.

Use of hemostatic agents for surgical bleeding in laparoscopic partial nephrectomy: Biomaterials perspective.

In recent years, there was an abrupt increase in the incidence of renal tumors, which prompt up the appearance of cutting-edge technology, including minimally invasive and organ-preserving approaches, such as laparoscopic partial nephrectomy (LPN). LPN is an innovative technique used to treat small renal masses that have been gaining popularity in the last few decades due to its promissory results. However, the bleeding control remains the main challenge since the majority of currently available hemostatic agents (HAs) used in other surgical specialities are inefficient in LPN. This hurried the search for effective HAs adapted for LPN surgical peculiarities, which resulted on the emergence of different types of topical HAs. The most promising are the natural origin HAs because of their inherent biodegradability, biocompatibility, and lowest toxicity. These properties turn them top interests' candidates as HAs in LPN. In this review, we present a deep overview on the progress achieved in the design of HAs based on natural origin polymers, highlighting their distinguishable characteristics and providing a clear understanding of their hemostat's role in LPN. This way it may be possible to establish a structure-composition properties relation, so that novel HAs for LPN can be designed to explore current unmet medical needs.

New endoscopic procedure for bladder wall closure: results from the porcine model.

Upper urinary tract urothelial carcinomas are usually managed by radical nephroureterectomy (RNU), often followed by intravesical chemotherapy to minimize recurrence. Open surgery is the gold standard procedure for RNU, but it associates with high morbidity, and it has been increasingly replaced by minimally invasive strategies, such as laparoscopy and endoscopy. Although effective, endoscopic ureteral excision leaves the bladder unsutured, increasing the risk of tumor spillage, and precluding the immediate administration of intravesical chemotherapy. Here we describe a new method to close the bladder wall after ureteral excision, using barbed sutures via the endoscopic access. Our results in 8 female pigs demonstrate that this method is effective to close the bladder wall. The procedure was completed in a median time of 24 min, and no adverse events were registered in the follow-up or at the three-week necropsy. This technique improves a previous approach described by our group because the device is more flexible and allows to tie the knots inside the bladder. Barbed sutures have been used in the clinical practice for other types of surgeries, and therefore this method can further be adapted to human patients with no safety concerns. Its use may allow to administer intravesical chemotherapy, which reduces tumor recurrence and improves patient outcomes.

In vivo assessment of a novel biodegradable ureteral stent.

PURPOSE: To perform an in vivo assessment of a newly developed biodegradable ureteral stent (BUS) produced with natural-based polymers. METHODS: The BUS is based on a patented technology combining the injection process with the use of supercritical fluid technology. Study was conducted at ICVS-University of Minho (Braga, Portugal) and a total of ten domestic pigs were used. In seven animals, the experimental BUS stent was inserted, whereas in the remaining a commercially available stent was used (6-Fr Biosoft® duo stents, Porges Coloplast, Denmark). Post-stenting intravenous pyelogram was used to evaluate the degree of hydronephrosis. The in vivo stent degradation was measured as function of the weight loss. Moreover, the tensile properties of the BUS were tested during in vivo degradation. After maximum 10 days, animals were killed and necropsy was performed. Tissues were compared between the stented groups as well as between the non-stented contralateral ureters and stented ureters in each group. Biocompatibility was assessed by histopathological grading. RESULTS: In all cases, the BUS was only visible during the first 24 h on X-ray, and in all cases the BUS was completely degraded in urine after 10 days, as confirmed on necropsy. During the degradation process, the mechanical properties of the BUS decreased, while the commercial ureteral stents remained constant. At all time-points after stent insertion, the level of hydronephrosis was minimal. Overall, animals stented with BUS had an average grade of hydronephrosis which was lower compared to the controls. The BUS showed better pathological conditions, and hence better biocompatibility when compared with commercial stents. CONCLUSIONS: Notwithstanding the limitations of the present study, the in vivo testing of our novel natural origin polymer-based BUS suggests this device to feature homogeneous degradation, good urine drainage, and high biocompatibility. Next steps will be to increase its stability, and to improve the radiopacity without compromising its degradation. Ultimately, clinical studies will be required to determine the safety and feasibility of its use in humans.

In Vitro and Ex Vivo Permeability Studies of Paclitaxel and Doxorubicin From Drug-Eluting Biodegradable Ureteral Stents.

A drug-eluting biodegradable ureteral stent (BUS) has been developed as a new approach for the treatment of urothelial tumors of upper urinary tract cancer. In a previous work, this system has proven to be a good carrier for anticancer drugs as a potential effective and sustainable intravesical drug delivery system. BUS has revealed to reduce in 75% the viability of human urothelial cancer cells (T24) after 72 h of contact and demonstrated minimal cytotoxic effect on human umbilical vein endothelial cells (HUVECs) which were used as a control. In this work, we studied the permeability of the anticancer drugs, such as paclitaxel and doxorubicin, alone or released from the BUS developed. We used 3 different membranes to study the permeability: polyethersulfone (PES) membrane, HUVECs cell monolayer, and an ex vivo porcine ureter. The ureter thickness was measured (864.51 µm) and histological analysis was performed to confirm the integrity of urothelium. Permeability profiles were measured during 8 h for paclitaxel and doxorubicin. The drugs per se have shown to have a different profile and as expected, increasing the complexity of the membrane to be permeated, the permeability decreased, with the PES being more permeable and the ex vivo ureter tissue being less permeable. The molecular weight has also shown to influence the permeability of each drug and a higher percentage for doxorubicin (26%) and lower for paclitaxel (18%) was observed across the ex vivo ureter. The permeability (P), diffusion (D), and partition (Kd) coefficients of paclitaxel and doxorubicin through the permeable membranes were calculated. Finally, we showed that paclitaxel and doxorubicin drugs released from the BUS were able to remain in the ex vivo ureter and only a small amount of the drugs can across the different permeable membranes with a permeability of 3% for paclitaxel and 11% for doxorubicin. The estimated amount of paclitaxel that remains in the ex vivo ureter tissue is shown to be effective to affect the cancer cell and not affect the noncancer cells.

Drug-eluting biodegradable ureteral stent: New approach for urothelial tumors of upper urinary tract cancer.

Upper urinary tract urothelial carcinoma (UTUC) accounts for 5-10% of urothelial carcinomas and is a disease that has not been widely studied as carcinoma of the bladder. To avoid the problems of conventional therapies, such as the need for frequent drug instillation due to poor drug retention, we developed a biodegradable ureteral stent (BUS) impregnated by supercritical fluid CO2 (scCO2) with the most commonly used anti-cancer drugs, namely paclitaxel, epirubicin, doxorubicin, and gemcitabine. The release kinetics of anti-cancer therapeutics from drug-eluting stents was measured in artificial urine solution (AUS). The in vitro release showed a faster release in the first 72h for the four anti-cancer drugs, after this time a plateau was achieved and finally the stent degraded after 9days. Regarding the amount of impregnated drugs by scCO2, gemcitabine showed the highest amount of loading (19.57µg drug/mg polymer: 2% loaded), while the lowest amount was obtained for paclitaxel (0.067µg drug/mg polymer: 0.01% loaded). A cancer cell line (T24) was exposed to graded concentrations (0.01-2000ng/ml) of each drugs for 4 and 72h to determine the sensitivities of the cells to each drug (IC50). The direct and indirect contact study of the anti-cancer biodegradable ureteral stents with the T24 and HUVEC cell lines confirmed the anti-tumoral effect of the BUS impregnated with the four anti-cancer drugs tested, reducing around 75% of the viability of the T24 cell line after 72h and demonstrating minimal cytotoxic effect on HUVECs.

In vitro bioactivity studies of ceramic structures isolated from marine sponges.

In this work, we focused on the potential of bioceramics from different marine sponges-namely Petrosia ficiformis, Agelas oroides and Chondrosia reniformis-for novel biomedical/industrial applications. The bioceramics from these sponges were obtained after calcination at 750 °C for 6 h in a furnace. The morphological characteristics were evaluated by scanning electron microscopy (SEM). The in vitro bioactivity of the bioceramics was evaluated in simulated body fluid (SBF) after 14 and 21 d. Observation of the bioceramics by SEM after immersion in SBF solution, coupled with spectroscopic elemental analysis (EDS), showed that the surface morphology was consistent with a calcium-phosphate (Ca/P) coating, similar to hydroxyapatite crystals (HA). Evaluation of the characteristic peaks of Ca/P crystals by Fourier transform infrared spectroscopy and x-ray diffraction further confirmed the existence of HA. Cytotoxicity studies were carried out with the different ceramics and these were compared with a commercially available Bioglass(®). In vitro tests demonstrated that marine bioceramics from these sponges are non-cytotoxic and have the potential to be used as substitutes for synthetic Bioglass(®).

Ketoprofen-eluting biodegradable ureteral stents by CO2 impregnation: In vitro study.

Ureteral stents are indispensable tools in urologic practice. The main complications associated with ureteral stents are dislocation, infection, pain and encrustation. Biodegradable ureteral stents are one of the most attractive designs with the potential to eliminate several complications associated with the stenting procedure. In this work we hypothesize the impregnation of ketoprofen, by CO2-impregnation in a patented biodegradable ureteral stent previously developed in our group. The biodegradable ureteral stents with each formulation: alginate-based, gellan gum-based were impregnated with ketoprofen and the impregnation conditions tested were 100 bar, 2 h and three different temperatures (35 °C, 40 °C and 50 °C). The impregnation was confirmed by FTIR and DSC demonstrated the amorphization of the drug upon impregnation. The in vitro elution profile in artificial urine solution (AUS) during degradation of a biodegradable ureteral stent loaded with ketoprofen was evaluated. According to the kinetics results these systems have shown to be very promising for the release ketoprofen in the first 72 h, which is the necessary time for anti-inflammatory delivery after the surgical procedure. The in vitro release studied revealed an influence of the temperature on the impregnation yield, with a higher impregnation yield at 40 °C. Higher yields were also obtained for gellan gum-based stents. The non-cytotoxicity characteristic of the developed ketoprofen-eluting biodegradable ureteral stents was evaluated in L929 cell line by MTS assay which demonstrated the feasibility of this product as a medical device.

Bioresorbable ureteral stents from natural origin polymers.

In this work, stents were produced from natural origin polysaccharides. Alginate, gellan gum, and a blend of these with gelatin were used to produce hollow tube (stents) following a combination of templated gelation and critical point carbon dioxide drying. Morphological analysis of the surface of the stents was carried out by scanning electron microscopy. Indwelling time, encrustation, and stability of the stents in artificial urine solution was carried out up to 60 days of immersion. In vitro studies carried out with simulated urine demonstrated that the tubes present a high fluid uptake ability, about 1000%. Despite this, the materials are able to maintain their shape and do not present an extensive swelling behavior. The bioresorption profile was observed to be highly dependent on the composition of the stent and it can be tuned. Complete dissolution of the materials may occur between 14 and 60 days. Additionally, no encrustation was observed within the tested timeframe. The ability to resist bacterial adherence was evaluated with Gram-positive Staphylococcus aureus and two Gram-negatives Escherichia coli DH5 alpha and Klebsiella oxytoca. For K. oxytoca, no differences were observed in comparison with a commercial stent (Biosoft(®) duo, Porges), although, for S. aureus all tested compositions had a higher inhibition of bacterial adhesion compared to the commercial stents. In case of E. coli, the addition of gelatin to the formulations reduced the bacterial adhesion in a highly significant manner compared to the commercial stents. The stents produced by the developed technology fulfill the requirements for ureteral stents and will contribute in the development of biocompatible and bioresorbable urinary stents.