Months Of Implantation Research Articles

Application of hs-CRP in Assessment of Tissue Inflammation Following Implantation of Biodegradable Polymer in Experiment.

Implants made of biodegradable polymers are replaced by regenerating tissues through inflammation. The changes occurring in tissues and the organism are of practical interest for studying the biocompatibility of the material and searching for systemic markers in the blood that reflect inflammation in peri-implantation tissues. The highly sensitive C-reactive protein (hs-CRP) measurements in blood and morphometric studies of tissue surrounding the implant were carried out in the experiment within three months of implantation of a biopolymer consisting of polycaprolactone (PCL) and polytrimethylene carbonate (PTMC). During the first month, tissue inflammation decreased, and the blood level of hs-CRP did not increase. The polymer biotransformation began in the tissues after a month of implantation and was accompanied by inflammation moving deeper into the matrix. Proliferation of inflammatory cells in tissues was reflected in an increase in the hs-CRP level three months after polymer installation. The result achieved confirmed the polymer's bioinertness. The level of hs-CRP in the blood of the animals correlated with the level of inflammation in peri-implantation tissues, reflecting the activity of inflammation in the process of polymer biotransformation. This inflammation protein can be recommended for assessing tissue processes following implantation of biopolymers and their biocompatibility.

Evaluation of Bi-layer Silk Fibroin Grafts for Inlay Vaginoplasty in a Rat Model.

Autologous tissues derived from bowel, buccal mucosa and skin are primarily used to repair or replace diseased vaginal segments as well as create neovaginas for male-to-female transgenders. These grafts are often limited by scarce tissue supply, donor site morbidity and post-operative complications. Bi-layer silk fibroin (BLSF) biomaterials represent potential alternatives for vaginoplasty given their structural strength and elasticity, low immunogenicity, and processing flexibility. The goals of the current study were to assess the potential of acellular BLSF scaffolds for vaginal tissue regeneration in respect to conventional small intestinal submucosal (SIS) matrices in a rat model of vaginoplasty. Inlay vaginoplasty was performed with BLSF and SIS scaffolds (N = 21 per graft) in adult female rats for up to 2months of implantation. Nonsurgical controls (N = 4) were investigated in parallel. Outcome analyses included histologic, immunohistochemical and histomorphometric evaluations of wound healing patterns; µ-computed tomography (CT) of vaginal continuity; and breeding assessments. Animals in both scaffold cohorts exhibited 100% survival rates with no severe post-operative complications. At 2months post-op, µ-CT analysis revealed normal vaginal anatomy and continuity in both graft groups similar to controls. In parallel, BLSF and SIS grafts also induced comparable constructive remodeling patterns and were histologically equivalent in their ability to support formation of vascularized vaginal neotissues with native tissue architecture, however with significantly less smooth muscle content. Vaginal tissues reconstructed with both implants were capable of supporting copulation, pregnancy and similar amounts of live births. BLSF biomaterials represent potential "off-the-shelf" candidates for vaginoplasty.

Establishing and Characterizing the Molecular Profiles, Cellular Features, and Clinical Utility of a Patient-Derived Xenograft Model Using Benign Prostatic Tissues

Benign prostatic hyperplasia (BPH) is a common condition marked by the enlargement of the prostate gland, which often leads to significant urinary symptoms and a decreased quality of life. The development of clinically relevant animal models is crucial for understanding the pathophysiology of BPH and improving treatment options. This study aims to establish a patient-derived xenograft (PDX) model using benign prostatic tissues to explore the molecular and cellular mechanisms of BPH. PDXs were generated by implanting fresh BPH (transition zone) and paired normal (peripheral zone) prostate tissue from 8 patients under the renal capsule of immunodeficient male mice. Tissue weight, architecture, cellular proliferation, apoptosis, prostate-specific marker expression, and molecular profiles of PDXs were assessed after 1 week and 1, 2, or 3 months of implantation by immunohistochemistry, enzyme-linked immunosorbent assay, transcriptomics, and proteomics. Responses to finasteride, a standard-of-care therapy, were evaluated. PDXs maintained histologic and molecular characteristics of the parental human tissues. BPH, but not normal PDXs, demonstrated significant increases in weight and cellular proliferation, particularly at 1 month. Molecular profiling revealed specific gene and protein expression patterns correlating with BPH pathophysiology. Specifically, an increased immune and stress response was observed at 1 week, followed by increased expression of proliferation markers and BPH-specific stromal signaling molecules, such as BMP5 and CXCL13, at 1 month. Graft stabilization to preimplant characteristics was apparent between 2 and 3 months. Treatment with finasteride reduced proliferation, increased apoptosis, and induced morphologic changes consistent with therapeutic responses observed in human BPH. Our PDX model recapitulates the morphologic, histologic, and molecular features of human BPH, offering a significant advancement in modeling the complex interactions of cell types in BPH microenvironments. These PDXs respond to therapeutic intervention as expected, providing a valuable tool for preclinical testing of new therapeutics that will improve the well-being of BPH patients.

Initial bone tissue reactions of hydroxyapatite/collagen-(3-glycidoxypropyl)trimethoxysilane injectable bone paste.

We have previously reported that a novel bioresorbable self-setting injectable bone paste composed of hydroxyapatite/collagen bone-like nanocomposite (HAp/Col) and (3-glycidoxypropyl)trimethoxysilane (GPTMS) was successfully prepared and was replaced with new bone within 3 months of implantation in defects created in porcine tibia. In this study, the HAp/Col-GPTMS paste was implanted into bone defects in rat tibiae to investigate the initial kinetics and bone tissue response. Even though more than 35% of GPTMS molecules should be eluted rapidly from directly injected pastes according to previously reported cell culture tests, in this study, energy-dispersive X-ray spectrometry did not detect Si (GPTMS) deposition in tissues surrounding the paste at 1 day postimplantation. Further, no abnormal inflammatory responses were observed in the surrounding tissues over the test period for both directly injected and prehardened pastes. Companying these observations with the results of the previous animal test (in which the paste was fully resorbed and was substituted with new bone), the eluted GPTMS resolved in no harm in vivo from the initial to final (completely resorbed) stages. Material resorption rates calculated from X-ray microcomputed tomography (μ-CT) images decreased with increasing in GPTMS concentration. Histological observations indicated that tartrate-resistant acid phosphatase (TRAP) active cells, (assumed to be osteoclasts), exist on the periphery of pastes. This result suggested that the paste was resorbed by osteoclasts in the same way as the HAp/Col. Since a good correlation was observed between TRAP active areas in histological sections and material resorption rate calculated from μ-CT, the TRAP activity coverage ratio offers the possibility to estimate the osteoclastic resorption ratio of materials, which are replaced with bone via bone remodeling process.

Efficacy of 3D printed anatomically equivalent thermoplastic polyurethane guide conduits in promoting the regeneration of critical-sized peripheral nerve defects.

Three-dimensional (3D) printing is an emerging tool for creating patient-specific tissue constructs analogous to the native tissue microarchitecture. In this study, anatomically equivalent 3D nerve conduits were developed using thermoplastic polyurethane (TPU) by combining reverse engineering and material extrusion (i.e., fused deposition modeling) technique. Printing parameters were optimized to fabricate nerve-equivalent TPU constructs. The TPU constructs printed with different infill densities supported the adhesion, proliferation, and gene expression of neuronal cells. Subcutaneous implantation of the TPU constructs for three months in rats showed neovascularization with negligible local tissue inflammatory reactions and was classified as a non-irritant biomaterial as per ISO 10993-6. To perform in vivo efficacy studies, nerve conduits equivalent to rat's sciatic nerve were fabricated and bridged in a 10 mm sciatic nerve transection model. After four months of implantation, the sensorimotor function and histological assessments revealed that the 3D printed TPU conduits promoted the regeneration in critical-sized peripheral nerve defects equivalent to autografts. ThisstudyprovedthatTPU-based 3D printed nerve guidance conduits can be created to replicate the complicated features ofnaturalnerves that can promote the regeneration of peripheral nerve defects and also show the potential to be extended to several other tissues for regenerative medicine applications.&#xD.

A robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) electrospun membrane for dura repair.

Typically occurring after trauma or neurosurgery treatments, dura mater defect and the ensuing cerebrospinal fluid (CSF) leakage could lead to a number of serious complications and even patient's death. Although numerous natural and synthetic dura mater substitutes have been reported, none of them have been able to fulfill the essential properties, such as anti-adhesion, leakage blockage, and pro-dura rebuilding. In this study, we devised and prepared a series of robust and biodegradable hydroxyapatite/poly(lactide-co-ε-caprolactone) (nHA/PLCL) membranes for dura repair via an electrospinning technique. In particular, PLLA/PCL (80/20) was selected for electrospinning due to its mechanical properties that most closely resembled natural dural tissue. Studies by SEM, XRD, water contact angle and in vitro degradation showed that the introduction of nHA would destroy PLCL's crystalline structure, which would further affect the mechanical properties of the nHA/PLCL membranes. When the amount of nHA added increased, so did the wettability and in vitro degradation rate, which accelerated the release of nHA. In addition, the high biocompatibility of nHA/PLCL membranes was demonstrated by in vitro cytotoxicity data. The in vivo rabbit dura repair model results showed that nHA/PLCL membranes provided a strong physical barrier to stop tissue adhesion at dura defects. Meanwhile, the nHA/PLCL and commercial group's CSF had a significantly lower number of inflammatory cells than the control groups, validating the nHA/PLCL's ability to effectively lower the risk of intracranial infection. Findings from H&E and Masson-trichrome staining verified that the nHA/PLCL electrospun membrane was more favorable for fostering dural defect repair and skull regeneration. Moreover, the relative molecular weight of PLCL declined dramatically after 3 months of implantation, according to the results of the in vivo degradation test, but it retained the fiber network structure and promoted tissue growth, demonstrating the good stability of the nHA/PLCL membranes. Collectively, the nHA/PLCL electrospun membrane presents itself as a viable option for dura repair.

Biodegradable high-nitrogen iron alloy anastomotic staples: In vitro and in vivo studies

For gastrointestinal anastomosis, metallic biodegradable staples have a broad application potential. However, both magnesium and zinc alloys have relatively low strength to withstand the repeated peristalsis of the gastrointestinal tract. In this study, we developed a novel kind of biodegradable high-nitrogen iron (HN–Fe) alloy wires (0.23 mm), which were fabricated into the staples. The tensile results showed that the ultimate tensile strength and elongation of HN–Fe wires were 1023.2 MPa and 51.0 %, respectively, which was much higher than those of other biodegradable wires. The degradation rate in vitro of HN–Fe wires was slightly higher than that of pure Fe wires. After 28 days of immersion, the tensile strength of HN–Fe wires remained not less than 240 MPa, meeting the clinical requirements. Furthermore, sixteen rabbits were enrolled to conduct a comparison experiment using HN–Fe and clinical Ti staples for gastroanastomosis. After 6 months of implantation, a homogeneous degradation product layer on HN–Fe staples was observed and no fracture occurred. The degradation rate of HN–Fe staples in vivo was significantly higher than that in vitro, and they were expected to be completely degraded in 2 years. Meanwhile, both benign cutting and closure performance of HN–Fe staples ensured that all the animals did not experience hemorrhage and anastomotic fistula during the observation. The anastomosis site healed without histopathological change, inflammatory reaction and abnormal blood routine and biochemistry, demonstrating good biocompatibility of HN–Fe staples. Thereby, the favorable performance makes the HN–Fe staples developed in this work a promising candidate for gastrointestinal anastomosis.

#2189 Percutaneous peritoneal dialysis catheter implantation

Abstract Background and Aims There are three main techniques to implant a peritoneal dialysis catheter (PDC): percutaneously, laparoscopically or through open surgery; and current guidelines recommend individualising according to previous abdominal surgeries and anaesthetic risk. Recent metanalysis show the percutaneous technique to be safe, non-inferior in catheter survival, and with an equal incidence in mechanic complications (within <3 months after implantation) and infectious complications (within <1 month after implantation) to laparoscopic technique. On the other side, as the percutaneous PDC implantation is a minimal intervention that requires neither surgery room nor over 24h hospitalisation, it allows for a lower waiting time to PDC implantation, a shorter period until usage, and it's economically efficient. Considering these benefits and its non-inferiority described in the literature, our centre started using this technique since 2018. In this study we analyse our results. Method This is an observational retrospective unicentric study, which included the first PDC implantation in adult patients between January 2019 and August 2023, were we analysed the mechanical and infectious complications associated with the implantation technique. All PDC were double-cuff straight Tenckhoff, placed using Seldinger technique with radioscopy. A single dose of prophylactic antibiotic was used. We considered as mechanic complication all those non-infectious incidences that required repositioning or replacement of the PDC within 3 months of implantation (excluding those patients whose catheter was removed because of kidney transplantation, death by other reasons non related to the procedure, or trespass to haemodialysis); and we considered as infectious complications all those peritonitis diagnosed the first month after implantation. Results We analysed a total of 147 patients, 71.4% were male, mean age was 61 years old, and mean kidney function at implantation time was 11.5 ml/min/1.73 m2. We found a total of 8.1% of mechanical complications (33% required repositioning and 66% required replacement) and 5.4% infectious complications. There were no deaths related to percutaneous PDC technique. Conclusion In this study we observe that mechanic or infectious complications associated with percutaneous PDC technique are similar to those published in the literature: ISPD guidelines recommend the incidence of peritonitis associated to catheter implantation to be less than 5%. And though there is no clear percentage of mechanical complications that are considered acceptable or unavoidable, many studies report a survival of 76-86% PDC at 90 days of implantation in percutaneous and laparoscopic procedures, without significant differences between them.

#2744 Analysis of bacteremia and mortality in patients with tunneled catheter for hemodialysis: a 14-years observational study

Abstract Background and Aims Infections are a leading cause of morbidity and mortality in hemodialysis patients. Tunneled catheters (TC) have been associated with increased risk of infection and death, but mortality rates are not widely reported. Our study aimed to analyse catheter infection-free survival and mortality of patients with this vascular access. Method This is a retrospective study of all TC inserted during the period of 1 January 2005 to 31 December 2019. The TC were inserted by nephrologists, following a preimplantation protocol agreed with the Infectious Diseases Service. Patients were followed up from the tunneled catheter insertion until the study end date (December 31, 2020), TC related bacteremia or died. Results In the 14-year period under study, 406 TC were implanted in 325 patients. A total of 85 tunneled catheter related bacteremia were diagnosed, resulting in an incidence of 0.40 per 1000 catheter days (81.1% after 6 months of implantation). The predominant microorganisms isolated were Gram-positive organisms: Staphylococcus epidermidis (48.4%); Staphylococcus aureus (28.0%). During the study, a total of 145 patients had the TC removed or exchanged due different causes. The main reasons for catheter removal were the adequate development and use of the arteriovenous fistula (48, 33.1%) and discharge from hemodialysis due to recovery of renal function, transfer to peritoneal dialysis or renal transplantation (47, 32.4%). Only in 26 (17.9%) patients, the TC was removed due to bacteremia at a median of 4.8 (1.0-8.0) days from the bacteremia. The median time to catheter removal for non-infection-related reasons was 448 (185-910) days, without significant differences with the TC related bacteremia group [430 (116-695)] (p=0.83). The 30-day mortality rate from the first TC related bacteremia was 8.7%. During the study period, a total of 168 (51.7%) patients died for different causes. Conclusion The incidence of bacteremia in our study was low and did not seem to have a relevant impact on catheter survival. The global mortality rate was similar to that reported in European registries for patients on renal replacement therapy. An implantation and management protocol, strict in prophylactic measures, could reduce the incidence of bacteremia and reduce its morbidity and mortality.

A comprehensive bench-to-bed look into the application of gamma-sterilized 3D-printed polycaprolactone/hydroxyapatite implants for craniomaxillofacial defects, an in vitro, in vivo, and clinical study

This study investigates the safety and efficacy of 3D-printed polycaprolactone/hydroxyapatite (PCL/HA) scaffolds for patient-specific cranioplasty surgeries, employing liquid deposition modeling (LDM) technology. This research is pioneering as it explores the impact of gamma radiation on PCL/HA scaffolds and utilizes printing ink with the highest content of HA known in the composite. The mechanical, morphological, and macromolecular stability of the gamma-sterilized scaffolds were verified before implantation. Subsequent research involving animal subjects was conducted to explore the effects of sterilized implants. Eventually, three clinical cases were selected for the implantation studies as part of a phase 1 non-randomized open-label clinical trial. It was shown that a 25 kGy gamma-ray dose for sterilizing the printed implants did not alter the required geometrical precision of the printed implants. The implants exhibited well-distributed HA and strength comparable to cancellous bone. Gamma radiation reduced hydrophobicity and water uptake capacity without inducing pyrogenic or inflammatory responses. Personalized PCL/HA substitutes successfully treated various craniomaxillofacial defects, including trauma-induced facial asymmetry and congenital deformities. HA nanoparticles in the ink stimulated significant osteoconductive responses within three months of implantation. Moreover, the results revealed that while larger implants may exhibit a slower bone formation response in comparison to smaller implants, they generally had an acceptable rate and volume of bone formation. This clinical trial suggests the application of a sterilized PCL/HA composite for craniomaxillofacial surgery is safe and could be considered as a substitute for autologous bone.

The treatment efficacy of bone tissue engineering strategy for repairing segmental bone defects under diabetic condition.

Diabetes mellitus is a systematic disease which exert detrimental effect on bone tissue. The repair and reconstruction of bone defects in diabetic patients still remain a major clinical challenge. This study aims to investigate the potential of bone tissue engineering approach to improve bone regeneration under diabetic condition. In the present study, decalcified bone matrix (DBM) scaffolds were seeded with allogenic fetal bone marrow-derived mesenchymal stem cells (BMSCs) and cultured in osteogenic induction medium to fabricate BMSC/DBM constructs. Then the BMSC/DBM constructs were implanted in both subcutaneous pouches and large femoral bone defects in diabetic (BMSC/DBM in DM group) and non-diabetic rats (BMSC/DBM in non-DM group), cell-free DBM scaffolds were implanted in diabetic rats to serve as the control group (DBM in DM group). X-ray, micro-CT and histological analyses were carried out to evaluate the bone regenerative potential of BMSC/DBM constructs under diabetic condition. In the rat subcutaneous implantation model, quantitative micro-CT analysis demonstrated that BMSC/DBM in DM group showed impaired bone regeneration activity compared with the BMSC/DBM in non-DM group (bone volume: 46 ± 4.4mm3 vs 58.9 ± 7.15mm3, *p < 0.05). In the rat femoral defect model, X-ray examination demonstrated that bone union was delayed in BMSC/DBM in DM group compared with BMSC/DBM in non-DM group. However, quantitative micro-CT analysis showed that after 6months of implantation, there was no significant difference in bone volume and bone density between the BMSC/DBM in DM group (199 ± 63mm3 and 593 ± 65mg HA/ccm) and the BMSC/DBM in non-DM group (211 ± 39mm3 and 608 ± 53mg HA/ccm). Our data suggested that BMSC/DBM constructs could repair large bone defects in diabetic rats, but with delayed healing process compared with non-diabetic rats. Our study suggest that biomaterial sacffolds seeded with allogenic fetal BMSCs represent a promising strategy to induce and improve bone regeneration under diabetic condition.

Implementation of an epicardial implantable MEMS sensor for continuous and real-time postoperative assessment of left ventricular activity in adult minipigs over a short- and long-term period.

The sensing of left ventricular (LV) activity is fundamental in the diagnosis and monitoring of cardiovascular health in high-risk patients after cardiac surgery to achieve better short- and long-term outcome. Conventional approaches rely on noninvasive measurements even if, in the latest years, invasive microelectromechanical systems (MEMS) sensors have emerged as a valuable approach for precise and continuous monitoring of cardiac activity. The main challenges in designing cardiac MEMS sensors are represented by miniaturization, biocompatibility, and long-term stability. Here, we present a MEMS piezoresistive cardiac sensor capable of continuous monitoring of LV activity over time following epicardial implantation with a pericardial patch graft in adult minipigs. In acute and chronic scenarios, the sensor was able to compute heart rate with a root mean square error lower than 2 BPM. Early after up to 1 month of implantation, the device was able to record the heart activity during the most important phases of the cardiac cycle (systole and diastole peaks). The sensor signal waveform, in addition, closely reflected the typical waveforms of pressure signal obtained via intraventricular catheters, offering a safer alternative to heart catheterization. Furthermore, histological analysis of the LV implantation site following sensor retrieval revealed no evidence of myocardial fibrosis. Our results suggest that the epicardial LV implantation of an MEMS sensor is a suitable and reliable approach for direct continuous monitoring of cardiac activity. This work envisions the use of this sensor as a cardiac sensing device in closed-loop applications for patients undergoing heart surgery.

3D printed Nanohydroxyapatite/Polyamide 66 scaffolds with balanced mechanical property and osteogenic ability for bone repair

The biomaterial requirements for bone tissue repair are extremely strict. It not only requires the biomaterial to have good biocompatibility and biological activity, but also requires sufficient mechanical strength. Polyamide 66 (PA66) and nano-hydroxyapatite (n-HA) have been widely investigated in bone tissue engineering scaffold, however, its composites require further research. In this study, the 3D printing technology was utilized to fabricate personalized n-HA/PA66 bone tissue scaffold. The mechanical properties of n-HA/PA66 composite can be adjusted by configuring different raw material components and applying different porosity. It was found that 50 % porosity n-HA/PA66 composite scaffold showed a uniform porous structure and a compressive strength of 33.9 MPa. The composite scaffold also exhibited excellent biological properties while improving mechanical properties, in vitro cell tests indicated that the 3D printed n-HA/PA66 composite scaffold promoted differentiation of bone marrow mesenchymal stem cells (BMSCs) into osteoblasts. In in vivo animal model proved that the scaffold promoted endogenous bone regeneration in rabbit patellar bone defects, with newly formed bone volume of 20.9 % after two months of implantation. This research proposed a 3D printed polyamide/nano-hydroxyapatite composite with balanced mechanical property and osteogenic ability for customized bone tissue repair, and it has promising application prospects.

Development of Environmental Sound Perception in Children with Cochlear Implant within 4 Months of Implantation.

The aim of the study was (1) to investigate the development of identification of environmental sounds in children with Cochlear Implantation (CI) within four months from switch on (i.e. at 0, 2 and 4 months) and (2) to see the effect of family type in the perception of environmental sounds. A longitudinal study design was utilized on a total of 18 children using CI within the chronological age range of 3 to 7 years. All participants underwent a closed set test of Environmental Sound Perception (ESP) to measure the longitudinal outcomes of ESP, at 0 (within 1 week of switch on), 2 months and 4 months of implant age. They were asked to identify the sounds by pointing at the picture representing the sound. Results using One-way and Two-way ANOVA demonstrated that at 0 month of implant age, the scores were 0%. At 2 months of implant age the scores ranged from 0 to 25% and at 4th month the scores ranged from 0 to 40%. There was a statistically significant improvement observed in ESP at every 2 months of testing from 0 to 4 months of implant age. However, effect of family type revealed no significant differences between the performances across the implant age. The current study reveals that identification of environmental sounds are one of the foremost benefits and early outcomes of CI in children. The perception of environmental sounds are constantly but gradually developing with increasing implant age. This information is useful to predict the performance of CI during rehabilitation and to set the therapy goals accordingly.

Degradable Nanohydroxyapatite-Reinforced Superglue for Rapid Bone Fixation and Promoted Osteogenesis.

Bone glue with robust adhesion is crucial for treating complicated bone fractures, but it remains a formidable challenge to develop a "true" bone glue with high adhesion strength, degradability, bioactivity, and satisfactory operation time in clinical scenarios. Herein, inspired by the hydroxyapatite and collagen matrix composition of natural bone, we constructed a nanohydroxyapatite (nHAP) reinforced osteogenic backbone-degradable superglue (O-BDSG) by in situ radical ring-opening polymerization. nHAP significantly enhances adhesive cohesion by synergistically acting as noncovalent connectors between polymer chains and increasing the molecular weight of the polymer matrix. Moreover, nHAP endows the glue with bioactivity to promote osteogenesis. The as-prepared glue presented a 9.79 MPa flexural adhesion strength for bone, 4.7 times that without nHAP, and significantly surpassed commercial cyanoacrylate (0.64 MPa). O-BDSG exhibited degradability with 51% mass loss after 6 months of implantation. In vivo critical defect and tibia fracture models demonstrated the promoted osteogenesis of the O-BDSG, with a regenerated bone volume of 75% and mechanical function restoration to 94% of the native tibia after 8 weeks. The glue can be flexibly adapted to clinical scenarios with a curing time window of about 3 min. This work shows promising prospects for clinical application in orthopedic surgery and may inspire the design and development of bone adhesives.

Morphological features of biological and tissue-engineered vascular patches remodeling: results of tests on a sheep model

One of the ways to reconstruct the arterial wall is endarterectomy with a vascular patch. The use of vascular wall prostheses made from existing materials can lead to complications with the need for reoperation. The search for new materials for the manufacture of vascular patches that have optimal compatibility with the vessel wall is still relevant.Aim: To study the dynamics and compare the morphological features of remodeling of tissue-engineered vascular patches from silk fibroin (SF) and biological xenopericardium (XP) flaps implanted into the wall of the sheep carotid artery.Material and Methods. Matrices from a 15% SF solution (n = 2) were prepared by electrospinning. For comparison, bovine pericardial flaps were used (n = 2). Vascular patches were implanted into the wall of the carotid artery in sheep for 2 and 6 months. A histological examination of explanted samples of vascular patches, scanning electron microscopy and confocal microscopy with specific immunofluorescent staining of the preparations were performed.Results. Based on the implanted SF-patch, neointima and neoadventitia were formed. After 2 months of implantation, the SFmatrix retained its structure; after 6 months, there were signs of moderate biodegradation of the material with the replacement of the vessel wall with its own tissue. There were no areas of calcification or massive inflammation. After 6 months, neointimal hyperplasia was detected in the projection of the implanted SF-patch. Based on the implanted XP-flap, neointima and neoadventitia were also formed. After 2 months, delamination of the implanted XP was revealed. After 6 months, neointimal hyperplasia was found in the projection of the XP-patch.Conclusion. Remodeling of the SF-patches and XP-flaps implanted into the wall of the sheep carotid artery followed the formation of a three-layer structure resembling the architecture of the vessel’s own wall, with signs of moderate biodegradation of the material. Neointimal hyperplasia is explained by insufficient compliance of the arterial wall and the patch and requires improvement in the composition of the implanted matrix.

Experimental study of the bilateral asymmetric single-rivet occluder device for transcatheter patent foramen ovale closure with reserved interatrial septal puncture area.

To evaluate a noval bilateral asymmetric single-rivet occluder with reserved interatrial septal puncture area for treating patent foramen ovale (PFO). The study established a pig model of patent foramen ovale (PFO) by puncturing the oval fossa and then performing high-pressure balloon dilation. A specially designed bilateral asymmetric occluder for the reserved interatrial septal puncture area was then. used to close the PFO through catheter-based intervention. The pigs were kept for 3 months before undergoing a second catheter-based intervention, involving interatrial septal puncture using a newly developed occluder in the reserved interatrial septal puncture area. During 6 months, the experimental pigs underwent assessment using digital subtraction angiography (DSA), echocardiography, and histological evaluation. A patent foramen ovale (PFO) model was successfully established in 6 pigs using the puncture atrial septum high-pressure balloon dilation method. The diameter of the unclosed PFO was measured (3.56 ± 0.25 mm). Using the newly developed occluder device, all 6 pigs with unclosed PFO underwent successful catheter-based closure surgeries, with intraoperative and postoperative transesophageal echocardiography showing excellent device positioning and complete closure without residual shunting. After 3 months of implantation, the catheter-based interatrial septal puncture was performed through the reserved interatrial septal puncture area, and all procedures were successful. Immediately following euthanasia, a histological examination revealed intact and undamaged occluder devices with visible puncture holes in the reserved interatrial septal puncture area. No fracture of the nitinol wire was observed, and the surface of the occluder device showed coverage of endothelial and connective tissues. Utilizing a bilateral asymmetric single-rivet occluder device implanted through the reserved interatrial septal puncture area has proven effective in closing PFO. After implantation, the occluder device allows subsequent interatrial septal puncture procedures through the reserved area. The novel occluder device demonstrated excellent closure performance, biocompatibility, and puncturability in the experiment. This indicates the feasibility of conducting further catheter-based interventions on the interatrial septum.

Contactless in-vivo temperature sensing in spinal cord based on magnetically bistable microwire

We have employed a magnetically bistable glass coated microwire as a passive contactless sensing element for in-vivo temperature monitoring in the rat’s spinal cord. The single piece (1 cm long) of Fe76Cr2Mo6B15Cu1 microwire was epidurally implanted into the adult female Wistar rats. The magnetization switching was measured in-vivo within the temperature range of 34.5–41.0 °C. Results show a monotonous temperature decrease of the switching time whose fitting to a second order polynomial dependence allows one to conclude a sensitivity down to 0.01ºC within the measured interval. Biocompatibility study shows that cells have a high affinity to the glass-coated microwire, and their viability is not influenced by the experimental condition under which the microwire’s response is measured. Finally, a histology study reveals that no histopathological changes or tissue reactions were observed even after 9 months of implantation.

Development of iodine based sustained release antimicrobial coatings for polyurethane voice prostheses.

Voice prostheses are known to fail in few weeks to several months of implantation due to the clogging mainly caused by microbial biofilm formation, which is a cause of concern. Iodine is a known broad-spectrum biocide and is reported to easily form complexes with various polymers. For long term device disinfection, strong iodine complexation that offers sustained iodine release for a prolonged period is essential. The present research work deals with the synthesis of a poly(methyl methacrylate-n-butyl acrylate-N-vinyl-2-pyrrolidone) (poly[MMA-BA-NVP]) tercopolymer through free radical polymerization for surface coating thermoplastic polyurethane (TPU) based voice prostheses. The NVP content in the tercopolymer was varied from 20% to 50% to optimise iodine loading and subsequent release. Base TPU coated with the tercopolymer was treated with 4% aqueous iodine solution at room temperature (28 ± 3 °C) for two hours. It was observed that the tercopolymer containing 35% N-vinyl-2-pyrrolidone (NVP), 32.5% methyl methacrylate (MMA) and 32.5% butyl acrylate (nBA) gave a stable coating on TPUs together with sustained iodine release for a prolonged period. Furthermore, the tercopolymer coated and iodine loaded TPUs exhibited excellent antimicrobial activity against Candida albicans, Staphylococcus aureus and Escherichia coli.

Effects of the multiscale porosity of decellularized platelet-rich fibrin-loaded zinc-doped magnesium phosphate scaffolds in bone regeneration.

In recent years, metallic ion-doped magnesium phosphate (MgP)-based degradable bioceramics have emerged as alternative bone substitute materials owing to their excellent biocompatibility, bone-forming ability, bioactivity, and controlled degradability. Conversely, incorporating a biomolecule such as decellularized platelet-rich fibrin (d-PRF) on scaffolds has certain advantages for bone tissue regeneration, particularly in enhanced osteogenesis and angiogenesis. The present study focuses on the impact of d-PRF-loaded multiscale porous zinc-doped magnesium phosphate (Zn-MgP) scaffolds on biodegradability, biocompatibility, and bone regeneration. Scaffolds were fabricated through the powder-metallurgy route utilizing naphthalene as a porogen (porosity = 5-43%). With the inclusion of a higher porogen, a higher fraction of macro-porosity (>20 μm) and pore interconnectivity were observed. X-ray diffraction (XRD) studies confirmed the formation of the farringtonite phase. The developed scaffolds exhibited a minimum ultimate compressive strength (UCS) of 8.5 MPa (for 40 Naph), which lies within the range of UCS of the cancellous bone of humans (2-12 MPa). The in vitro assessment via immersion in physiological fluid yielded a higher deposition of the calcium phosphate (CaP) compound in response to increased macro-porosity and interconnectivity (40 Naph). Cytocompatibility assessed using MC3T3-E1 cells showed that the incorporation of d-PRF coupled with increased porosity resulted the highest cell attachment, proliferation, and viability. For further evaluation, the developed scaffolds were implanted in in vivo rabbit femur condylar defects. Radiography, SEM, OTC labelling, and histology analysis after 2 months of implantation revealed the better invasion of mature osteoblastic cells into the scaffolds with enhanced angiogenesis and superior and accelerated healing of bone defects in d-PRF-incorporated higher porosity scaffolds (40 Naph). Finally, it is hypothesized that the combination of d-PRF incorporation with multiscale porosity and increased interconnectivity facilitated better bone-forming ability, good biocompatibility, and controlled degradability within and around the Zn-doped MgP scaffolds.