Implantation Site Research Articles

Needle infiltration assisted explantation technique for peripheral nerve stimulator leads.

Peripheral nerve stimulation is a neuromodulation modality that is increasing used to treat chronic pain. The permanent peripheral nerve stimulator systems, while easy to place are designed to stay in place and scar at the implantation site. There is a paucity of literature on explantation techniques for peripheral nerve stimulators. In this report describe a needle infiltration assisted technique for lead explantation. This novel technique is minimally invasive, cost effective and utilizes a combination of fluoroscopy and ultrasound imaging. We describe the successful use of this technique in 3 cases in our practice without any adverse events. There are many situations which might require a permanent peripheral nerve stimulator to be explanted such as infection, lead erosion, patient request or need for patient to undergo magnetic resonance imaging (MRI). In these scenarios, we propose a novel needle infiltration assisted technique of explantation that is safe, effective and easy to replicate.

Fibroblast matrix implants - a better alternative for incisional hernia repair?

The standard surgical procedure for abdominal hernia repair with conventional prosthetic mesh still results in a high recurrence rate. In the present study, we propose a Fibroblast
Matrix Implant (FMI), which is a three-dimensional (3D) Poly-L-lactic acid (PLLA) scaffold coated with collagen (matrix) and seeded with fibroblasts, as an alternative mesh for hernia repair. The matrix was seeded with fibroblasts (cellularized) and treated with a Conditioned
Medium (CM) of human Umbilical Cord Mesenchymal Stem Cells (hUC-MSC). Fibroblast proliferation and function were assessed and compared between treated with CM hUC-MSC and untreated group, 24 hours after seeding onto the matrix (n=3). To study the matrices in vivo, the hernia was surgically created on male Sprague Dawley rats and repaired with four different grafts (n=3), including a commercial mesh (mesh group), a matrix without cells
(cell-free group), a matrix seeded with fibroblasts (FMI group), and a matrix seeded with fibroblasts and cultured in medium treated with 1 % CM hUC-MSC (FMI-CM group). In vitro examination showed that the fibroblasts' proliferation on the matrices (treated group) did not differ significantly compared to the untreated group. CM hUC-MSC was able to promote the collagen synthesis of the fibroblasts, resulting in a higher collagen concentration compared to the untreated group. Furthermore, the in vivo study showed that the matrices allowed fibroblast growth and supported cell functionality for at least 1 month after implantation. The highest number of fibroblasts was observed in the FMI group at the 14-day endpoint, but at the 28-day endpoint, the FMI-CM group had the highest. Collagen deposition area and neovascularization at the implantation site were observed in all groups without any significant difference between the groups. FMI combined with CM hUC-MSC may serve as a better option for hernia repair, providing additional reinforcement which in turn should reduce hernia recurrence.&#xD.

Biphasic Calcium Phosphate and Activated Carbon Microparticles in a Plasma Clot for Bone Reconstruction and In Situ Drug Delivery: A Feasibility Study

The development of bone-filling biomaterials capable of delivering in situ bone growth promoters or therapeutic agents is a key area of research. We previously developed a biomaterial constituting biphasic calcium phosphate (BCP) microparticles embedded in an autologous blood or plasma clot, which induced bone-like tissue formation in ectopic sites and mature bone formation in orthotopic sites, in small and large animals. More recently, we showed that activated carbon (AC) fiber cloth is a biocompatible material that can be used, due to its multiscale porosity, as therapeutic drug delivery system. The present work aimed first to assess the feasibility of preparing calibrated AC microparticles, and second to investigate the properties of a BCP/AC microparticle combination embedded in a plasma clot. We show here, for the first time, after subcutaneous (SC) implantation in mice, that the addition of AC microparticles to a BCP/plasma clot does not impair bone-like tissue formation and has a beneficial effect on the vascularization of the newly formed tissue. Our results also confirm, in this SC model, the ability of AC in particle form to adsorb and deliver large molecules at an implantation site. Altogether, these results demonstrate the feasibility of using this BCP/AC/plasma clot composite for bone reconstruction and drug delivery.

Development of a Novel Formulation of Bioactive Glass Based Calcium Phosphate Cement for Bone Grafting

AbstractParticulate bone grafting material can travel from the implantation site and diminish the magnitude of required bone formation response and hence its effectiveness. An easily prepared moldable graft that rapidly sets rigid in situ would alleviate this problem and in this study, such an injectable bone graft material is presented. By combining calcium phosphate (CP) salts with a bioactive glass (BG) mixed with a 2.5% Na2HPO4 solution a novel BG‐based calcium phosphate cement (CPC) is produced. Immersion in Tris buffer and simulated body fluid (SBF) solutions result in the rapid generation of octacalcium phosphate (OCP) and hydroxyapatite (HA) phases – a pre‐requisite for “bioactivity”. Cement‐conditioned media does not result in any cytotoxic potential with respect to MTT activity, DNA content, or alkaline phosphatase activity with an osteoblastic cell line. Application of the cement into standardized surgical defects in the minipig mandible results in short‐term, moderate irritation at 3 and 6 weeks and complete replacement of cement with new bone at 12 weeks.

Scanning efficacy of p-Chips implanted in the wing and leg of the Big Brown Bat (Eptesicus fuscus)

Abstract Individual marking techniques are critical for studying animals, especially in the wild. Current marking methods for bats (Order Chiroptera) have practical limitations and some can cause morbidity. We tested the p-Chip (p-Chip Corp.)—a miniaturized, laser light-activated microtransponder—as a prospective marking technique in a captive research colony of Big Brown Bats (Eptesicus fuscus). We assessed long-term readability and postimplantation effects of p-Chips injected subcutaneously above the second metacarpal (wing; n = 30) and the tibia (leg; n = 13 in both locations). Following implantation (Day 0), p-Chips were scanned with a hand-held ID reader (wand) on postimplantation days (PIDs) 1, 8, 15, 22, 32, 60, 74, 81, 88, 95, and over 1 year later (PID 464). For each trial, we recorded: (1) animal handling time; (2) scan time; (3) number of wand flashes; (4) p-Chip visibility; and (5) overall condition of the bat. Average scan times for p-Chips implanted in both the wing and leg increased over the duration of the study; however, the number of wand flashes decreased, suggesting that efficacy of p-Chip recording increased with user experience. Importantly, over 464 days both the visibility and readability of p-Chips in the wing remained high and superior to tags in the leg, establishing the second metacarpal as the preferred implantation site. Observed morbidity and mortality in captive bats with p-Chips was similar to baseline values for bats without these tags. Because scan efficiency on PID 464 was comparable with earlier days, this indicates that p-Chips implanted in the wing may be suitable as a long-term marking method. Our provisional results suggest that p-Chips are viable for extended field testing to see if they are suitable as an effective alternative to traditional methods to mark bats.

Optimization of a mouse model of pancreatic cancer to simulate the human phenotypes of metastasis and cachexia

BackgroundPancreatic ductal adenocarcinoma (PDAC) presents with a high mortality rate. Two important features of PDAC contribute to this poor outcome. The first is metastasis which occurs in ~ 80% of PDAC patients. The second is cachexia, which compromises treatment tolerance for patients and reduces their quality of life. Although various mouse models of PDAC exist, recapitulating both metastatic and cachectic features have been challenging.MethodsHere, we optimize an orthotopic mouse model of PDAC by altering several conditions, including the subcloning of parental murine PDAC cells, implantation site, number of transplanted cells, and age of recipient mice. We perform spatial profiling to compare primary and metastatic immune microenvironments and RNA sequencing to gain insight into the mechanisms of muscle wasting in PDAC-induced cachexia, comparing non-metastatic to metastatic conditions.ResultsThese modifications extend the time course of the disease and concurrently increase the rate of metastasis to approximately 70%. Furthermore, reliable cachexia endpoints are achieved in both PDAC mice with and without metastases, which is reminiscent of patients. We also find that cachectic muscles from PDAC mice with metastasis exhibit a similar transcriptional profile to muscles derived from mice and patients without metastasis.ConclusionTogether, this model is likely to be advantageous in both advancing our understanding of the mechanism of PDAC cachexia, as well as in the evaluation of novel therapeutics.

Contributions of Alveolar Bone Density and Habitual Chewing Side to the Unilateral Failure of Orthodontic Mini-Screws: A Cross-Sectional Study

This study aimed to analyze the relationship between bone density, habitual chewing side (HCS), and mini-screw stability to investigate the intra-individual factors contributing to mini-screw failure. This retrospective study included 86 sides in 43 adults, who underwent bilateral maxillary mini-screw placement with subsequent unilateral failure of the mini-screw. Pre-treatment cone-beam computed tomography was used to measure the buccal cortical bone thickness and bone density on the failed and successful sides. Pre-treatment mandibular kinesiographic records were used to determine the HCS. Paired t-tests, one-proportion z-tests, and multivariable multilevel Poisson regression were used to examine the statistical significance. The buccal cortical bone thicknesses were 0.93 ± 0.27 mm (unsuccessful side) and 1.01 ± 0.27 mm (successful side), with no significant difference. The bone density on the unsuccessful side (1059.64 ± 202.64 mg/cm3) was significantly lower than the success side (1317.89 ± 332.23 mg/cm3). Regarding HCS, 27.9% of failures occurred on the preferred side, and 62.8% occurred on the non-preferred side. After adjusting for all factors, the non-preferred side showed a 2.22 times higher prevalence ratio for mini-screw failure than the preferred side. HCS is significantly related to mini-screw stability, while the cortical bone thickness, bone density, and site of mini-screw implantation were not correlated.

An improved method for generating human spinal cord neural stem cells

Neural stem cells have exhibited efficacy in pre-clinical models of spinal cord injury (SCI) and are on a translational path to human testing. We recently reported that neural stem cells must be driven to a spinal cord fate to optimize host axonal regeneration into sites of implantation in the injured spinal cord, where they subsequently form neural relays across the lesion that support significant functional improvement. We also reported methods of deriving and culturing human spinal cord neural stem cells derived from embryonic stem cells that can be sustained over serial high passage numbers in vitro, providing a potentially optimized cell source for human clinical trials. We now report further optimization of methods for deriving and sustaining cultures of human spinal cord neural stem cell lines that result in improved karyotypic stability while retaining anatomical efficacy in vivo. This development improves prospects for safe human translation.

One-Stage Lateral Sinus Floor Elevation Using Different Grafts: A Systematic Review of Controlled Clinical Trials.

The purpose of this systematic review was to assess histological and imaging outcomes related to new bone formation around implants, inserted simultaneously with sinus augmentation, comparing different types of grafts. Systematic Review was carried out following the Preferred Reporting Items for Systematic Reviews and Meta- Analysis (PRISMA), and the Cochrane Handbook for Systematic Reviews of Interventions. LILACS/BVS, Medline/PubMed, Cochrane Library and Embase databases, including gray literature and manual investigation, were searched to identify clinical trials reporting human histological and imaging data of bone formation around implants, inserted into the maxillary sinus at the same moment of the elevation and augmentation procedure, using several materials. Study selection, risk of bias (Rob 2.0 or ROBINS I), quality of evidence (GRADE), and data collection were performed by two independent reviewers. Of the 1101 potentially eligible articles, 44 were retrieved, 12 were assessed for eligibility and 5 were included in this systematic review (4 randomized and one controlled clinical trials). As a result, 130 grafted sinuses with 179 installed implants in 103 patients, aged between 24 and 79 years and followed up from 6 to 15 months, were analyzed. The heterogeneity between studies did not allow the data to be combined for meta-analyses. All graft materials proved to be viable options for the intervention. The use of BCP was related to higher bone-to-implant contact. All the assessed grafts are viable options for the intervention addressed. The use of some material is justified to maintain the sinus volume and allow bone formation in the apical site of implants under the sinus membrane. Longer chair time and the morbidity of the donor site should be considered when choosing autogenous bone. Synthetic biphasic materials can be selected for this intervention due to superior values of %BIC when compared to DBB.

Site selection of micro-implant anchorages in the infrazygomatic crest in adult orthodontic patients.

To determine the optimal placement of miniscrews, this study compared adult male and female patients in terms of cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest region. The cone beam computed tomography imaging data of 200 patients (20-30 years old; 100 males and 100 females) were collected. The right maxillary posterior teeth in the sagittal plane were divided into six levels from proximal to distal, and three measurement sites were positioned at vertical distances of 8, 10, and 12 mm from the cementum. Cortical bone density, cortical bone thickness, and available bone width were measured in 18 measurement sites in the infrazygomatic crest and analyzed statistically. The highest cortical bone density, cortical bone thickness, and available bone width in the infrazygomatic crest in adult male and female patients were at the level of the interradicular space between the maxillary second premolar and maxillary first molar. The bone cortical density and thickness increased with vertical height, whereas the available bone width decreased with increasing vertical height. Differences were observed in cortical bone density, cortical bone thickness, and available bone width between adult male and female patients. The optimal implantation sites of the micro-implant anchorages in the infrazygomatic crest were at the level of the interradicular space between the maxillary second premolar and the maxillary first molar, and the vertical height of the optimal implantation site in males was appropriately higher than that in females.

Research progress of biodegradable staples in gastrointestinal anastomosis

Since the 1960s, anastomosis instruments have become integral in gastrointestinal procedures, employing Titanium (Ti) alloy staples. These staples, however, remain permanently in the body, potentially inciting inflammatory reactions, compromising computed tomography scans, and causing diagnostic inaccuracies. This scenario underscores the imperative for biodegradable surgical staples, spurring research into materials that exhibit both superior biodegradability and mechanical integrity. Current investigations are focused on Magnesium (Mg), Zinc (Zn), and their alloys for their exemplary biodegradability, mechanical strength, and biocompatibility, making them promising candidates for gastrointestinal anastomosis. This review encapsulates the latest advancements in biodegradable surgical staples, emphasizing material and structural enhancements. It details the mechanical attributes of wires intended for staple fabrication, the corrosion dynamics across varied environments such as in vitro immersion solutions and in vivo implantation sites and the impact of structural refinements on staple biodegradability. Additionally, it contrasts the benefits and limitations of Mg-based and Zn-based staples and offers insights into the potential and hurdles in developing biodegradable surgical staples, thereby fostering further exploration in this field.

The significance of light chronodestruction in the development of the embryotoxic effect in the experiment

   Objective. To assess the significance of light chronodestruction in the development of the embryotoxic effect in the experiment.   Materials and methods. The experiment was conducted on 60 female rats of the Wistar line. To assess the significance of chronodestruction in the development of embryotoxic effect, the uterus was isolated in the experiment, in which the number of implantation sites, the total number of embryos, the number of live and dead embryos, and the number of resorptions were estimated. The number of corpus luteum in the harvested ovaries was estimated. In addition, the mean embryo weight (g) and mean craniocaudal size (mm) were recorded. Indicators of embryotoxic effects of light deprivation were determined by pre- and post-implantation death, which was calculated in accordance with methodological recommendations.   Results. Exposure to light deprivation reduces the number of implantation sites as of 7th, 14th and 21st days by 1,5-1,8 times, the total number of embryos by 1,6-1,8 times, the number of living embryos by 2,2-9 times and increases the number of dead embryos as of 14th and 21st days by 4-5,5 times, the number of resorptions – 1,6-11 times. The average craniocaudal size (mm) of embryos in experimental animals was recorded below control values by 1,5 times, 1,3 and 3,7 times by 7th, 14th, 21st days respectively. In females exposed to light deprivation, there was a significant increase in pre-implantation mortality by 35-41,8 times and post-implantation mortality by 7,2-20,4 times compared to the control.   Conclusion. Light deprivation may have a negative effect on pregnancy and fetal development in female rats, which is confirmed by an increase in pre- and post-implantation mortality.

Off-the-Shelf Synthetic Biodegradable Grafts Transform In Situ into a Living Arteriovenous Fistula in a Large Animal Model.

Current vascular access options require frequent interventions. In situ tissue engineering (TE) may overcome these limitations by combining the initial success of synthetic grafts with long-term advantages of autologous vessels by using biodegradable grafts that transform into autologous vascular tissue at the site of implantation. Scaffolds (6 mm-Ø) made of supramolecular polycarbonate-bisurea (PC-BU), with a polycaprolactone (PCL) anti-kinking-coil, are implanted between the carotid artery and jugular vein in goats. A subset is bio-functionalized using bisurea-modified-Stromal cell-derived factor-1α (SDF1α) derived peptides and ePTFE grafts as controls. Grafts are explanted after 1 and 3 months, and evaluated for material degradation, tissue formation, compliance, and patency. At 3 months, the scaffold is resorbed and replaced by vascular neo-tissue, including elastin, contractile markers, and endothelial lining. No dilations, ruptures, or aneurysms are observed and grafts are successfully cannulated at termination. SDF-1α-peptide-biofunctionalization does not influence outcomes. Patency is lower in TE grafts (50%) compared to controls (100% patency), predominantly caused by intimal hyperplasia. Rapid remodeling of a synthetic, biodegradable vascular scaffold into a living, compliant arteriovenous fistula is demonstrated in a large animal model. Despite lower patency compared to ePTFE, transformation into autologous and compliant living tissue with self-healing capacity may have long-term advantages.

Results of bone grafting using a xenogenic cortical plate BiOTECK

BACKGROUND: The fundamental condition that determines the effectiveness of treatment, with immediate and long-term positive results, is the amount of bone tissue in the jaws at the proposed implantation site. Defects in the dentition to a large extent and severe atrophy of the bone tissue of the jaws due to the loss of teeth significantly limit the use of dental implantation. It is reasonable to expand the indications for the use of dental implants in cases of atrophy of the jaw bone tissue in the installation site. This allows the optimization of surgical techniques aimed at increasing the volume of the jaw bone tissue, such as the use of new osteoplastic materials for guided bone regeneration.
 AIM: This study aimed to analyze the results of a jawbone graft using a BiOTECK xenogeneic cortical plate.
 MATERIALS AND METHODS: The test group consisted of 22 patients (11 men and 11 women) with jawbone atrophy. All patients underwent bone graft surgery using a BiOTECK xenogeneic cortical plate (BiOTECK, Italy).
 In the course of the study, all patients with jawbone loss underwent a dynamic clinical and X-ray examination during the following stages: during the dental implant surgery planning stage aimed at determining the volume of the bone tissue available and identifying the associated conditions and diseases (prior to conducting an osteoplastic procedure), prior to dental implant installation (6 months after osteoplastic surgery), and prior to the start of the orthopedic stage of treatment (12 months after osteoplastic surgery).
 RESULTS: The cone beam computed tomography data were analyzed and statistically processed to obtain the results. It was revealed that the values of the “bone densitometry” indicator increased 6 months after the bone graft using the BiOTECK xenogeneic cortical plate, and the values of the “densitometric density of jaw bone tissue” indicator increased.
 Immediately after bone grafting using the BiOTECK xenogeneic cortical plate, the thickness of the bone tissue of the upper jaw increased by an average of 5.0±0.1 mm and that of the lower jaw increased by an average of 3.9±0.1 mm. In the first stage of the dental implant surgery (6 months after osteoplastic procedure), due to resorption, the thickness of the bone tissue of the alveolar process of the upper jaw decreased by 1.1±0.1 mm and amounted to 6.8±0.1 mm (bone resorption rate: 13.9%), and the thickness of the bone tissue of the alveolar process of the lower jaw decreased by 0.8±0.2 mm and amounted to 6.6±0.3 mm (bone resorption rate: 10.3%).
 CONCLUSION: The clinical and X-ray results obtained 1 year after installing dental implants and performing bone graft surgery using the BiOTECK xenogeneic cortical plate indicate a stable volume of marginal bone tissue in the area of alveolar crest reconstruction.

[Expert consensus on the whole-course management of implantable venous access port in the upper arm of cancer patients (2023 Edition)].

With the widespread application of ultrasound-guided Sedinger puncture techniques and intracardiac electrocardiogram positioning technology, implantable intravenous drug delivery device (IVAP) in the upper arm has been recognized by the majority of medical personnel and cancer patients due to its advantages of hiding scars and completely avoiding the risk of hemothorax and pneumothorax. In order to standardize the clinical application of IVAP via the upper arm approach in cancer patients, improve the success rate of implantation, reduce complications and improve patient satisfaction, the Breast Cancer Expert Committee of the National Cancer Quality Control Center consulted guidelines and the latest evidence-based evidences and established the expert consensus on the whole-course management of implantable venous access port in the upper arm of cancer patients, in order to provide reference for the standard application of IVAP in the upper arm. The consensus mainly introduces the indications, contraindications, preoperative evaluation, implantation site, operation procedure, utilization and maintenance, complications and management, medical staff training and patient education of IVAP in the upper arm, in order to provide reference for clinical staff.

Planar amorphous silicon carbide microelectrode arrays for chronic recording in rat motor cortex

Chronic implantation of intracortical microelectrode arrays (MEAs) capable of recording from individual neurons can be used for the development of brain-machine interfaces. However, these devices show reduced recording capabilities under chronic conditions due, at least in part, to the brain's foreign body response (FBR). This creates a need for MEAs that can minimize the FBR to possibly enable long-term recording. A potential approach to reduce the FBR is the use of MEAs with reduced cross-sectional geometries. Here, we fabricated 4-shank amorphous silicon carbide (a-SiC) MEAs and implanted them into the motor cortex of seven female Sprague-Dawley rats. Each a-SiC MEA shank was 8 μm thick by 20 μm wide and had sixteen sputtered iridium oxide film (SIROF) electrodes (4 per shank). A-SiC was chosen as the fabrication base for its high chemical stability, good electrical insulation properties, and amenability to thin film fabrication. Electrochemical analysis and neural recordings were performed weekly for 4 months. MEAs were characterized pre-implantation in buffered saline and in vivo using electrochemical impedance spectroscopy and cyclic voltammetry at 50 mV/s and 50,000 mV/s. Neural recordings were analyzed for single unit activity. At the end of the study, animals were sacrificed for immunohistochemical analysis. We observed statistically significant, but small, increases in 1 and 30 kHz impedance values and 50,000 mV/s charge storage capacity over the 16-week implantation period. Slow sweep 50 mV/s CV and 1 Hz impedance did not significantly change over time. Impedance values increased from 11.6 MΩ to 13.5 MΩ at 1 Hz, 1.2 MΩ–2.9 MΩ at 1 kHz, and 0.11 MΩ–0.13 MΩ at 30 kHz over 16 weeks. The median charge storage capacity of the implanted electrodes at 50 mV/s was 58.1 mC/cm2 on week 1 and 55.9 mC/cm2 on week 16, and at 50,000 mV/s, 4.27 mC/cm2 on week 1 and 5.93 mC/cm2 on week 16. Devices were able to record neural activity from 92% of all active channels at the beginning of the study, At the study endpoint, a-SiC devices were still recording single-unit activity on 51% of electrochemically active electrode channels. In addition, we observed that the signal-to-noise ratio experienced a small decline of −0.19 per week. We also classified observed units as fast and slow repolarizing based on the trough-to-peak time. Although the overall presence of single units declined, fast and slow repolarizing units declined at a similar rate. At recording electrode depth, immunohistochemistry showed minimal tissue response to the a-SiC devices, as indicated by statistically insignificant differences in activated glial cell response between implanted brains slices and contralateral sham slices at 150 μm away from the implant location, as evidenced by GFAP staining. NeuN staining revealed the presence of neuronal cell bodies close to the implantation site, again statistically not different from a contralateral sham slice. These results warrant further investigation of a-SiC MEAs for future long-term implantation neural recording studies.

Poly(hydroxyalkanoates): Emerging Biopolymers in Biomedical Fields and Packaging Industries for a Circular Economy

AbstractPoly(hydroxyalkanoates) (PHAs) are a class of sustainable, bio-based thermoplastic polymers with attractive physiochemical properties, including non-toxicity, biocompatibility, elastomeric behavior by design, and piezoelectric characteristics. In the ongoing effort to reduce plastics waste, PHAs can play a substantial role due to their inherent biodegradability free of microplastics, customizable properties, and versatile applications. This includes their tremendous potential in a broad range of biomedical applications. Biomass-based materials have recently gained great interest in the health sector, given the vast amount of interdisciplinary research in bioengineering and medicine. Implantable biomaterials should not elicit any negative response at the implantation site, which differentiates them from general-purpose polymers. PHAs do not induce any thrombosis or antigenic response even after being in contact with blood in the human body during long-term use. The biocompatibility of PHAs is also a key factor in the rapid growth and proliferation of tissues onto and within these materials when served as tissue engineering scaffolds. By application, the biomedical field was estimated to be the second-largest market share for PHAs, in terms of volume, in 2022. While PHA-based materials bring forth a broad range of opportunities, they also present challenges that have limited their widespread use and a greater market share. A better understanding of their physiochemical properties and biodegradation rates, production challenges, and the need for cost-effective strategies are some of the hurdles that need to be addressed. This review paper provides an overview of the commonly used PHA homopolymers and copolymers in biomedical fields and packaging industries. The introduction of the manuscript presents the concept of bioplastics and their environmental significance, highlighting the urgent need for alternatives to conventional fossil-based plastics. The next sections briefly cover the synthesis, properties, as well as homopolymer and copolymer formulations, followed by the application of PHA-based materials in the biomedical field. Current opportunities and challenges, together with some insight into the future gathered from the published studies, have been brought in the concluding section of this paper.

Parahisian Stimulation Through Unusual Vascular Access - Case Report

Introduction: To report the case of a patient with a total atrioventricular block with significant ventricular dysfunction whose pacemaker implantation and physiological stimulation occurred through the iliac vein due to tortuosities in other vessels that prevented the procedure. Method: Information was obtained by reviewing the medical records, interviewing the patient, photographing the diagnostic methods to which the patient was submitted, and reviewing the literature. Conclusion: The reported case and published publications bring to light the discussion of pacemaker implantation sites and physiological stimulation in a complex situation that, although it occurs in a minority of cases, when well it is capable of obtaining satisfactory results.

Preventing septic implant failures in osteoporotic hip fractures using antibiotic-loaded functionalized nanocement

Osteoporosis is a prevalent skeletal disorder and the most common cause of debilitating hip fractures, primarily affecting post-menopausal women and elderly people. Implants used to stabilize osteoporotic fragility fractures are susceptible to bacterial infections, which further deteriorate the implantationsite. In the current study, we developed a nanocement-based treatment for tackling hip implant infection in an osteoporotic rat model. The development of osteoporosis was confirmed by an 80% decrease in serum estradiol levels and a further reduced T-score value of −4.170 ± 0.411 for femur neck canal. Further, an infected K-wire was implanted in femoral neck canal to induce implant-associated osteomyelitis. In order to combat infection and promote bone healing, it was followed by debridement and implantation of rifampicin-loaded nanocement functionalized with various combinations of bone marrow MSCs (bMSC) exosomes, bone morphogenetic protein-2 (BMP-2) and zoledronic acid (ZA). The findings of this study demonstrated the potential of exosomes as an alternative for reducingBMP-2 dosage, and the treatment promoted successful bone regeneration withenhanced mechanical strength, and a significant decrease in bacterial load. Improved bone remodeling and matrix deposition at the implantation site were confirmed by DXA, micro-CT, and histology. Further, immunohistochemical staining showed increased expression of collagen I and CD31, which indicated bone matrix deposition and vascularization, respectively, while reduced expression of α-SMA and NOS2 confirmed a reduction in fibrosis and inflammation, respectively. Overall, our one-step treatment strategy has the potential to prevent implant-associated bone infection in osteoporotic hip fractures, promote bone formation, and enhance the mechanical strength of osteoporotic bone, thereby preventing subsequent secondary fractures.

CD4+ and CD8+ T cells reduce inflammation and promote bone healing in response to titanium implants

T cells are adaptive immune cells essential in pathogenic response, cancer, and autoimmune disorders. During the integration of biomaterials with host tissue, T cells modify the local inflammatory environment by releasing cytokines that promote inflammatory resolution following implantation. T cells are vital for the modulation of innate immune cells, recruitment and proliferation of mesenchymal stem cells (MSCs), and formation of functional tissue around the biomaterial implant. We have demonstrated that deficiency of αβ T cells promotes macrophage polarization towards a pro-inflammatory phenotype and attenuates MSC recruitment and proliferation in vitro and in vivo. The goal of this study was to understand how CD4+ and CD8+ T cells, subsets of the αβ T cell family, impact the inflammatory response to titanium (Ti) biomaterials. Deficiency of either CD4+ or CD8+ T cells increased the proportion of pro-inflammatory macrophages, lowered anti-inflammatory macrophages, and diminished MSC recruitment in vitro and in vivo. In addition, new bone formation at the implantation site was significantly reduced in T cell-deficient mice compared to T cell-competent mice. Deficiency of CD4+ T cells exacerbated these effects compared to CD8+ T cell deficiency. Our results show the importance of CD4+ and CD8+ T cells in modulating the inflammatory response and promoting new bone formation in response to modified Ti implants. Statement of significanceCD4+ and CD8+ T cells are essential in modulating the peri-implant microenvironment during the inflammatory response to biomaterial implantation. This study shows that deficiency of either CD4+ or CD8+ T cell subsets altered macrophage polarization and reduced MSC recruitment and proliferation at the implantation site.