Search Results (113)

Atherosclerosis remains a leading cause of cardiovascular mortality despite advances in pharmacological and interventional therapies. Current treatment approaches face limitations including systemic side effects, inadequate local drug delivery, and restenosis following vascular interventions. Gel-based technologies offer unique advantages through tunable mechanical properties, controlled degradation kinetics, high drug-loading capacity, and potential for stimuli-responsive therapeutic release. This review examines gel platforms across multiple scales and applications in atherosclerosis research and intervention. First, gel-based in vitro models are discussed. These include hydrogel matrices simulating plaque microenvironments, three-dimensional cellular culture platforms, and microfluidic organ-on-chip devices. These devices incorporate physiological flow to investigate disease mechanisms under controlled conditions. Second, therapeutic strategies are addressed through macroscopic gels for localized treatment. These encompass natural polymer-based, synthetic polymer-based, and composite formulations. Applications include stent coatings, adventitial injections, and catheter-delivered depots. Natural polymers often possess intrinsic biological activities including anti-inflammatory and immunomodulatory properties that may contribute to therapeutic effects. Third, nano- and microgels for systemic delivery are examined. These include polymer-based nanogels with stimuli-responsive drug release responding to oxidative stress, pH changes, and enzymatic activity characteristic of atherosclerotic lesions. Inorganic–organic composite nanogels incorporating paramagnetic contrast agents enable theranostic applications by combining therapy with imaging-guided treatment monitoring. Current challenges include manufacturing consistency, mechanical stability under physiological flow, long-term safety assessment, and regulatory pathway definition. Future opportunities are discussed in multi-functional integration, artificial intelligence-guided design, personalized formulations, and biomimetic approaches. Gel technologies demonstrate substantial potential to advance atherosclerosis management through improved spatial and temporal control over therapeutic interventions. Full article

During catheter interventional procedures, the catheter inevitably encounters the vessel wall. When the push–pull force at the catheter–vessel wall interface exceeds a certain threshold, it may cause vascular damage. The mechanical feedback at the catheter–blood interface are still areas that urgently need to be addressed. This study provides essential experimental data and mechanical feedback to inform and validate such simulations. Therefore, this article first analyzed the movement form and mechanical state of the catheter and blood vessel during vascular interventional surgery. Based on this, this paper analyzes the movement forms and mechanical states of the catheter and blood vessels during intervention, focusing on the contact force between the catheter and blood vessels. The results of the three-point bending test indicate that the bending deformation force of the tube increases as the radius decreases, and the overall deformation progresses from elastic deformation to the yield limit. The normal force of the tube on the lumen and the average push–pull force at the end of the tube are all positively correlated with the moving speed and bending degree of the tube. Statistical analysis revealed that the degree of lumen curvature had a significantly greater influence on the push–pull force than catheter motion speed. The above research provides guidance for friction at the medical device–vessel interface and coating design. Full article

Background/Objectives: Arteriovenous grafts (AVGs) are critical for hemodialysis access in patients with inadequate native vasculature. The Xeltis aXess graft, a novel bioresorbable vascular access conduit, promotes endogenous tissue restoration. While early outcomes have been promising, longer-term data remain limited. This report presents the longest reported, four-year follow-up on two of the first implanted aXess devices. Case Summaries: Case 1: A 64-year-old woman underwent aXess graft placement on 10 June 2021, between the right brachial artery and vein. She experienced graft thrombosis after 12 months and 18 months, both of which were successfully resolved with thrombectomy, in one instance in combination with drug-coated balloon (DCB) angioplasty. The graft remains functional. Case 2: A 76-year-old man received an aXess graft on 11 June 2021, in the left arm. After 6 months, he underwent balloon and DCB angioplasty for graft–vein (G–V) anastomosis stenosis. After 28 months, to resolve multiple pseudoaneurysms, followed by aneurysm resection and AVG reconstruction at month 29, a tunneled catheter was placed to perform dialysis sessions in the meantime. At month 44, graft-venous (G–V) angioplasty with DCB was performed to resolve G–V and axillary vein stenoses diagnosed at month 43. The graft remains in use. Results: Both patients retained functional dialysis access after four years, despite requiring multiple interventions for thrombosis, stenosis, and pseudoaneurysms. Conclusions: These cases demonstrate that the aXess graft can maintain functionality over four years with appropriate management, although close surveillance and reinterventions may be required. Full article

Multidrug-resistant (MDR) pathogens and biofilm-associated infections represent a major global health concern, particularly in the context of medical devices such as catheters, tubing, and blood sampling devices. Biofilms, responsible for up to 85% of human infections, confer a high level of microbial resistance and compromise device performance and patient safety. In this study, the antibiofilm potential of Syzygium aromaticum (clove) essential oil was investigated through an in vitro assay. GC–MS analysis revealed eugenol (72.77%) as the predominant compound, accompanied by β-caryophyllene (14.72%) and carvacrol (2.09%). The essential oil exhibited notable antimicrobial activity, producing inhibition zones of 30.5 ± 4.5 mm against Staphylococcus aureus, 24.5 ± 0.5 mm against Micrococcus luteus, 16.0 ± 2.0 mm against Escherichia coli, 13.0 ± 1.0 mm against Pseudomonas aeruginosa, 23.5 ± 1.5 mm against Candida albicans, and 24.0 ± 2.0 mm against C. glabrata. A marked reduction in biofilm biomass observed on polyvinyl chloride (PVC) surfaces. The application of clove essential oil as a coating for PVC-based medical devices remains a future possibility that requires formulation and in vivo testing. This strategy is proposed as potentially eco-safe, although environmental toxicity and biocompatibility have not yet been evaluated. It could contribute to the prevention of biofilm formation in arterial sampling systems and other healthcare-related materials, thereby enhancing device safety and longevity. Full article

Long-term intravenous therapies often necessitate the use of peripherally inserted central catheters (PICCs). Antimicrobial-coated PICCs have been introduced to minimize central line-associated bloodstream infections (CLABSIs). A decision-analytic cost-effectiveness model was developed from a societal perspective, utilizing real-world data concerning PICC-related complications and costs from Class 3A hospitals and community hospital settings in China. The analysis compared the quality-adjusted life years (QALYs) for patients receiving antimicrobial-coated PICCs versus standard PICCs, with catheter-associated costs included. Incremental cost-effectiveness ratios (ICERs) were calculated in Chinese Yuan (CNY) per QALY gained. Patients with antimicrobial-coated PICCs experienced slightly fewer complication-related events, leading to significantly lower costs for managing complications. In the Class 3A hospital setting, the average total cost per patient was lower with antimicrobial-coated PICCs (CNY 62,800) compared to standard PICCs (CNY 102,900), primarily due to the reduced expenses for treating CLABSIs and related unknown fever. The ICER demonstrated that the coated PICC was the strongest option, showing a negative ICER (cost-saving of approximately CNY 4 million per QALY gained in the base-case Class 3A hospital scenario). In community hospital care scenarios, the cost advantage of antimicrobial-coated PICCs remained. Thus, the antimicrobial-coated PICC strategy was cost-saving, providing equal or improved health outcomes at lower costs in China’s medical center and community hospitals, making it a more efficient choice for long-term vascular access. Full article

Healthcare-associated infections are a serious concern, particularly in patients with intravascular catheters. In this study, we developed a novel ampicillin-loaded polycaprolactone (PCL)-coated polyurethane catheter (PUC) wherein polymethylhydrosiloxane (PMHS) enhanced the adhesion between PCL and PUC, ensuring coating durability. PUC were first treated with PMHS, followed by PCL coatings containing 1, 3, or 6 wt% ampicillin. Antibacterial activity against Listeria innocua and Escherichia coli was evaluated using the plate counting method over 40 d. Scanning electron microscopy confirmed that the coating was uniform and stable for over 40 d. Furthermore, antibacterial efficacy was maintained for 10, 30, and 40 d for the 1, 3, and 6 wt% ampicillin coatings, respectively. Compared to the uncoated controls, the bacterial counts were reduced by over 99.9%. Thus, PMHS pretreatment of a catheter coated with ampicillin-loaded PCL exhibited sustained antibacterial activity. Our findings show PMHS enhances the coating adhesion and ensures gradual uniform degradation of the PCL layer. Full article

Background: Intravascular catheters (ICs) are critical medical devices but require frequent replacement due to the risk of bacterial colonization, which can lead to bloodstream infections. This process causes patient discomfort and incurs significant health and economic costs. Aim: To evaluate the inhibitory activity of natural extracts as potential IC coatings to prevent colonization by methicillin-resistant Staphylococcus aureus (MRSA). Methods: Thirty-six clinical MRSA isolates, obtained from ICs using the Maki technique, were tested. Three natural extracts were evaluated: garlic extract enriched in thiosulfinates (allicin: 7 mg/g), grape extract enriched in proanthocyanidins (92% proanthocyanidins), and propolis extract. Chlorhexidine gluconate (CHG) served as the bactericidal control. The minimum inhibitory concentration (MIC) was determined using the broth microdilution technique with optical density measurements and resazurin-based viability confirmation. The minimum bactericidal concentration (MBC) was assessed from viable cells in wells exceeding the MIC. Results: All tested extracts exhibited bacteriostatic activity against MRSA isolates. The grape extract demonstrated the lowest MIC₉₀ (3.125 mg/mL), followed by propolis extract (MIC₉₀ = 12.5 mg/mL) and garlic extract (MIC₉₀ = 50 mg/mL). Only the propolis extract showed bactericidal activity (MBC = 25 mg/mL). While CHG outperformed the natural extracts, their activity against MRSA suggests potential clinical utility. Conclusion: The natural extracts studied display promising bacteriostatic activity against MRSA isolates from ICs, with propolis extract additionally showing bactericidal effects. Although less potent than CHG, these extracts offer a potential alternative for combating multidrug-resistant pathogens in clinical settings, warranting further investigation for use as IC coatings. Full article

Biofilms develop in sequential steps resulting in the formation of three-dimensional communities of microorganisms that are encased in self-produced extracellular polymeric substances. Biofilms play a key role in device-associated infections, such as catheter-associated urinary tract infections (CAUTIs), because they protect microorganisms from standard antimicrobial therapies. Current strategies to prevent biofilm formation in catheter-related infections, including prophylactic antibiotics and antibiotic-coated catheters, have been unsuccessful. This finding highlights a need for novel approaches to address this clinical problem. In this study, biofilm-forming phenotypes of common Gram-negative bacteria associated with CAUTIs were treated with antisense peptide nucleic acids (PNAs), and biofilm biomass and bacterial viability were quantified after 24 h of treatment. A cocktail of PNAs targeting the global regulator genes rsmA, amrZ, and rpoS in Pseudomonas aeruginosa significantly reduced viability and thus appropriately eliminated biofilm biomass. Antisense-PNAs against these same gene targets and the motility regulator gene motA inhibited biofilm formation among isolates of Klebsiella pneumoniae, Enterobacter cloacae, and Escherichia coli but did not reduce bacterial viability. These results suggest that antisense-PNAs are a promising new technology in preventing biofilm formation in urinary catheters, especially as a potential complement to conventional antimicrobials. Full article

Background/Objectives: Lichen sclerosus is a chronic lymphocyte-mediated inflammatory disorder with a predilection for the anogenital region. It is a common cause of urethral stricture disease in males. The gold standard treatment is considered to be surgical reconstruction; however, there are many patients who are not suitable or not willing to undergo surgery. Cutaneous lichen sclerosus restricted to the foreskin, prepuce or glans is often response to topical corticosteroids; however, the use of intraurethral corticosteroids for urethral involvement has limited research. Methods: We conducted a retrospective cohort study on 18 patients with histologically confirmed lichen sclerosus and associated urethral stricture disease. They were treated with clean intermittent self catheterisation using a hydrophilic catheter coated with 0.05% betamethasone ointment. International Prostate Symptom Score with Quality of Life scores were measured prior to treatment and at follow-up intervals. Results: There was significant improvement in International Prostate Symptom Score and Quality of Life scores at 3 months, 12 months and 24 months, with only 1 patient ceasing treatment due to intolerance. One patient required a single repeat endoscopic dilatation following a period of non-compliance with treatment. Conclusions: Intraurethral corticosteroids with clean-intermittent self-catheterisation is effective and well tolerated for treating lichen sclerosus-associated urethral stricture disease in the short to intermediate term for patients not willing to undergo urethroplasty. Full article

Biofilms, structured communities of microorganisms encased in an extracellular matrix, are a major cause of persistent infections, particularly when formed on medical devices. This study investigated the kinetics of biofilm formation by Escherichia coli and Pseudomonas aeruginosa, two clinically significant pathogens, on two medical-grade polymers: polyether ether ketone (PEEK) and polyamide 12 (PA12). Using a modified crystal violet staining method and spectrophotometric quantification, we evaluated biofilm development over time on polymer granules and catheter segments composed of these materials. Results revealed that PEEK surfaces supported significantly more biofilm formation than PA12, with peak accumulation observed at 24 h for both pathogens. Conversely, PA12 demonstrated reduced bacterial adhesion and lower biofilm biomass, suggesting surface characteristics less conducive to microbial colonization. Additionally, the study validated a reproducible protocol for assessing biofilm formation, providing a foundation for evaluating anti-biofilm strategies. While the assays were performed under static in vitro conditions, the findings highlight the importance of material selection and early prevention strategies in the design of infection-resistant medical devices. This work contributes to the understanding of how surface properties affect microbial adhesion and underscores the critical need for innovative surface modifications or coatings to mitigate biofilm-related healthcare risks. Full article

Introduction: Two-stage revision with an antibiotic-loaded, temporary static cement spacer is a common treatment for periprosthetic joint infection (PJI) of the knee. However, limited data exists on in vivo antibiotic elution kinetics after spacer implantation. This pilot study uses the technique of microdialysis (MD) to collect intra-articular knee samples. The aim was to evaluate MD as an intra-articular sampling method to detect spacer-eluted antibiotics within 72 h after surgery and to determine whether they show specific elution kinetics. Methods: Ten patients (six male, four female; age median 71.5 years) undergoing two-stage revision for knee PJI were included. A MD catheter was inserted into the joint during explantation of the infected inlying implant and implantation of a custom-made static spacer coated with COPAL cement (0.5 g gentamicin (G) and 2 g vancomycin (V)). Over 72 h postoperatively, samples were collected and analyzed for spacer-eluted antibiotics, intravenously administered antibiotics (e.g., cefazolin and cefuroxime), metabolic markers (glucose and lactate), and Interleukin-6 (IL-6). Local and systemic levels were compared. Results: All catheters were positioned successfully and well tolerated for 72 h. Antibiotic concentrations in MD samples peaked within the first 24 h (G: median 9.55 µg/mL [95% CI: 0.4–17.36]; V: 37.57 µg/mL [95% CI: 3.26–81.6]) and decreased significantly over 72 h (for both p < 0.05, G: 4.27 µg/mL [95% CI: 2.26–7.2]; V: 9.69 µg/mL [95% CI: 3.86–24]). MD concentrations consistently exceeded blood levels (p < 0.05), while intravenously administered antibiotics showed higher blood concentrations. Glucose in MD samples decreased from 17.71 mg/dL to 0.89 mg/dL (p < 0.05). IL-6 and lactate concentrations showed no difference between MD and blood samples. Conclusions: Monitoring antibiotics eluted by a static spacer with intra-articular MD for 72 h is feasible. Gentamicin and vancomycin levels remained above the minimal inhibitory concentration. Differentiating infection from surgical response using metabolic and immunological markers remains challenging. Prolonged in vivo studies with MD are required to evaluate extended antibiotic release in two-stage exchanges. Full article

Background and Objective: Benign prostatic hyperplasia (BPH) and urethral stricture (US) are common causes of lower urinary tract symptoms in ageing men, often requiring repeated interventions. Conventional treatments of US, such as urethrotomy and mechanical dilation, have high recurrence rates. The Optilume drug-coated balloon catheter system, which combines mechanical dilation with paclitaxel delivery, has emerged as a minimally invasive alternative. This systematic review assesses its efficacy and safety in the management of BPH and US. Methods: A systematic search of PubMed was conducted for studies published between August 2020 and October 2023. Eligible studies included randomised controlled trials (RCTs), cohort studies, and case reports evaluating Optilume’s therapeutic effects. Key outcomes analysed included symptom relief, urinary flow improvement, recurrence rates, and adverse events. Results: Seven studies met the inclusion criteria, including five on US and two on BPH. The ROBUST trial series demonstrated sustained improvements in urinary flow rates and symptom scores in US patients over follow-up periods of up to four years. The EVEREST-1 and PINNACLE trials reported significant symptom relief and preserved sexual function in BPH patients, with a favourable safety profile and minimal complications. Conclusions: Optilume appears to be a promising alternative to conventional endoscopic treatments for US and BPH, offering durable symptom relief with a low complication rate. Further long-term studies are required to confirm its efficacy and cost-effectiveness in routine clinical practice. Full article

Intermittent catheterization mitigates urinary retention for over 300,000 people in the US every year, but can cause microtrauma in the urothelium, compromising its barrier function and increasing the risk of pathogen entry, which may affect user health. To reduce adverse effects, intermittent catheters (ICs) with increased lubricity are used. A common strategy to enhance IC lubricity is to apply a polyvinylpyrrolidone (PVP) coating to ICs; however, this coating can become adhesive upon drying, potentially leading to microtrauma. An alternative approach for lubricity is the migration of integrated amphiphilic surfactant (IAS) within the IC to the surface. The present work examines differences in urethral microtrauma caused by the simulated catheterization of ex vivo porcine urethral tissue using PVP-coated and IAS ICs. Scanning electron microscopy and fluorescence microscopy of the tissue showed the removal of the apical cell layer after contact with the PVP-coated ICs, but not the IAS IC. More extracellular matrices and DNA were observed on the PVP-coated ICs than the IAS IC after tissue contact. Contact angle analysis of the polar and dispersive components of the surface energy demonstrated that the PVP-coated ICs promoted mucoadhesion, while the IAS IC limited mucoadhesion. Overall, the results indicate that IAS ICs cause less microtrauma to urethral tissue than traditional PVP-coated ICs. Full article

Many kinds of silicones are a wide family of hybrid inorganic–organic polymers which have valuable physical and chemical properties and find plenty of practical applications, not only industrial, but also numerous medical and pharmaceutical ones, mainly due to their good thermal and chemical stability, hydrophobicity, low surface tension, biocompatibility, and bio-durability. The important biomedical applications of silicones include drains, shunts, and catheters, used for medical treatment and short-term implants; inserts and implants to replace various body parts; treatment, assembly, and coating of various medical devices; breast and aesthetic implants; specialty contact lenses; and components of cosmetics, drugs, and drug delivery systems. The most important achievements concerning the biomedical and pharmaceutical applications of silicones, their copolymers and blends, and also silanes and low-molecular-weight siloxanes have been summarized and updated. The main physiological properties of organosilicon compounds and silicones, and the methods of antimicrobial protection of silicone implants, have also been described and discussed. The toxicity of silicones, the negative effects of breast implants, and the environmental effects of silicone-containing personal care and cosmetic products have been reported and analyzed. Important examples of the 3D printing of silicone elastomers for biomedical applications have been presented as well. Full article

Background: Healthcare-associated infections (HAIs) significantly increase morbidity, mortality, and healthcare costs. Among HAIs, catheter-associated infections are particularly prevalent due to the susceptibility of catheters to microbial contamination and biofilm formation, especially with prolonged use. Biofilms act as infection reservoirs, complicating treatment and often requiring catheter removal, thus extending hospital stays and increasing costs. Recent technological advances in catheter design have focused on integrating antifouling and antimicrobial coatings to mitigate or prevent biofilm formation. Methods: We developed COPESIL^®, a novel silicone rubber embedded with PEGylated copper nanoparticles designed to reduce microbial contamination on catheter surfaces. We conducted in vitro assays to evaluate the antimicrobial and antibiofilm efficacy of COPESIL^® against pathogens commonly implicated in catheter-associated urinary tract infections. Additionally, the safety profile of the material was assessed through cytotoxicity evaluations using HepG2 cells. Results: COPESIL^® demonstrated substantial antimicrobial activity, reducing contamination with Escherichia coli and Klebsiella pneumoniae by >99.9% and between 93.2% and 99.8%, respectively. Biofilm formation was reduced by 5.2- to 7.9-fold for E. coli and 2.7- to 2.8-fold for K. pneumoniae compared to controls. Cytotoxicity assays suggest the material is non-toxic, with cell viability remaining above 95% after 24 h of exposure. Conclusions: The integration of PEGylated copper nanoparticles into a silicone matrix in COPESIL^® represents a promising strategy to enhance the antimicrobial properties of catheters. Future studies should rigorously evaluate the long-term antimicrobial efficacy and clinical safety of COPESIL^®-coated catheters, with a focus on their impact on patient outcomes and infection rates in clinical settings. Full article