A Fibrin-Thrombin Based In Vitro Perfusion System to Study Flow-Related Prosthetic Heart Valves Thrombosis

Prosthetic heart valve (PHV) replacement has increased the survival rate and quality of life for heart valve-diseased patients. However, PHV thrombosis remains a critical problem associated with these procedures. To better understand the PHV flow-related thrombosis problem, appropriate experimental models need to be developed. In this study, we present an in vitro fibrin clot model that mimics clot accumulation in PHVs under relevant hydrodynamic conditions while allowing real-time imaging. We created 3D-printed mechanical aortic valve models that were inserted into a transparent glass aorta model and connected to a system that simulates human aortic flow pulse and pressures. Thrombin was gradually injected into a circulating fibrinogen solution to induce fibrin clot formation, and clot accumulation was quantified via image analysis. The results of valves positioned in a normal versus a tilted configuration showed that clot accumulation correlated with the local flow features and was mainly present in areas of low shear and high residence time, where recirculating flows are dominant, as supported by computational fluid dynamic simulations. Overall, our work suggests that the developed method may provide data on flow-related clot accumulation in PHVs and may contribute to exploring new approaches and valve designs to reduce valve thrombosis.

Surgeon, Pathologist and Pathology Technician Effects on Nodal Yield after a Neck Dissection

PURPOSE/OBJECTIVE(S)

A minimum nodal count of 18 lymph nodes has been associated with improved survival after neck dissection and has been suggested as a head and neck cancer quality metric. Despite its critical importance, factors affecting nodal yield are poorly studied. In particular, the relative contribution of surgeons, pathologists, and pathology technicians has not been evaluated. The purpose of this study was to understand both patient and provider related factors that affect nodal yield after neck dissection for patients with oral cavity squamous cell carcinoma (OCSCC).

MATERIALS/METHODS

This retrospective cohort study involved review of all adult patients with OCSCC undergoing primary neck dissection between 2000-2020 at an academic medical center. The outcome of interest was a continuous variable denoting the number of nodes removed per side during neck surgery. Surgeon and pathologist year of experience were calculated and represented in quartiles. A multilevel multivariable linear regression model was used to assess the association of surgeon/pathologist experience quartiles with nodal yield, controlling for patient age, comorbidity index, previous cancer, tumor grade, and clinical nodal status.

RESULTS

The 508 patients included in our cohort were treated by 5 surgeons and 6 pathologists and involved 44 pathology technicians. Of these patients, 310 (61.0%) were male with a mean age of 63. Oral tongue primary tumors were 46.7% of the cohort, while 64.4% of patients had cT1-T2 tumors, and 65.2% were cN0. The mean nodal yield was 24.2 nodes. The ANOVA analysis revealed significant difference in mean nodal yield by surgeon (p-value = 0.03), pathologist (p-value<0.01) and pathology technician (p-value = 0.037). After accounting for patient-level characteristics and patient clustering by surgeon, increasing surgeon experience was found to be significantly associated with a higher nodal yield (joint significance of surgeon years of experience quartiles < 0.01). Specifically, when compared to surgeons with the least experience (1st quartile), those whose years of experience fell into the 2nd, 3rd, and 4th quartile removed 4.69 (95% CI: 0.97 to 7.92), 4.47 (95% CI: 0.33 to 7.87), and 7.37 (95% CI: 0.73 to 11.27) more lymph nodes. Meanwhile, there was no association between pathologist experience and nodal yield (joint significance of pathologist years of experience quartiles = 0.27). Additionally, previous cancer diagnosis and cN0 disease were significantly associated with lower nodal yield (all p-values = 0.02).

CONCLUSION

This study demonstrates an independent association between increasing surgeon experience and higher nodal yields. Importantly, it also demonstrates that pathologists and pathology technicians contribute to the variation in nodal yield, and their contribution should not be overlooked in the implementation of a lymph node yield-based quality metric.

Controversies in regenerative medicine: should knee joint osteoarthritis be treated with mesenchymal stromal cells?

Knee joint osteoarthritis is a complex immunological and degenerative disease. Current treatment strategies fail to alter its progression. Mesenchymal stromal cell (MSC) therapy for osteoarthritis has been object of research for more than 30 years. The aim of MSC therapy is intended to be holistic, with regeneration of all affected knee joint structures. The paracrine effect of the MSC secretome has been shown to be central for the regenerative capacity of MSCs. Activation of local knee-joint-specific MSCs leads to an immunomodulatory, anti-catabolic, anti-apoptotic and chondrogenic stimulus. Preclinical models have demonstrated the symptom- and disease-modifying effects of MSC therapy. At the bedside, there is evidence that autologous and allogeneic MSC therapy shows significant improvement in symptom-modifying and functional outcome. Despite this, a variety of contradictory clinical outcomes are available in the literature. The effectiveness of MSC therapy is still unclear, although there have been promising results. Regarding the diversity of cell sources, isolation, culture protocols and other factors, a comparison of different studies is difficult. Clinical translation of disease-modifying effects has not yet been shown. This narrative review presents a controversial overview of the current preclinical and clinical studies on MSC therapy in knee joint osteoarthritis.

[Minimally invasive lumbopelvic stabilization of sacral fracture and sacroiliac injury]

OBJECTIVE

Rapid mobilization with full weight bearing by minimally invasive fixation of Os ilium to L5 in fractures of the sacrum and disruption of the sacroiliac joint (SIJ).

INDICATIONS

Unstable injuries of the posterior pelvic ring in fractures of the sacrum and disruption of the SIJ.

CONTRAINDICATIONS

Fracture of ilium and not injury related implants in the screw trajectory, neurological deficits regarding the fracture, decubitus in the area of surgical approach.

SURGICAL TECHNIQUE

Minimally invasive screw placement in the pedicles of L5, access of ilium screw via the posterior superior iliac spine. Radiological display for the iliacal screw bearing trajectory in Os Ilium as a drop-shaped/triangle canal. Insert a Jamshidi needle orthograde in the beam path, change to guide wire and placement of iliacal screw after resection of the bone in the screw head area. Submuscular insertion of the longitudinal rods, in case of double-sided instrumentation similar procedure on the opposite side, reduction of the fracture and fixation of the rods to screws.

POSTOPERATIVE MANAGEMENT

Postoperative mobilization with full weight bearing under physiotherapeutic guidance.

RESULTS

Patients treated with lumbopelvic stabilization in our facility between 2012 and 2017 were identified via the hospital database and retrospectively evaluated. In 24 patients with median age of 60.1 years and a follow-up-time of 11.8 months, we found no implant displacement, infection and no wound healing problems. Full weight bearing was permitted in 21 of 24 cases, in 3 cases partial load bearing due to other injuries. Three patients reported moderate mechanical irritation of iliacal screws; 1 patient reported severe irritability with removal of the implants after bony healing of fracture 1 year postoperatively.

Synthetic neural-like computing in microbial consortia for pattern recognition

Complex biological systems in nature comprise cells that act collectively to solve sophisticated tasks. Synthetic biological systems, in contrast, are designed for specific tasks, following computational principles including logic gates and analog design. Yet such approaches cannot be easily adapted for multiple tasks in biological contexts. Alternatively, artificial neural networks, comprised of flexible interactions for computation, support adaptive designs and are adopted for diverse applications. Here, motivated by the structural similarity between artificial neural networks and cellular networks, we implement neural-like computing in bacteria consortia for recognizing patterns. Specifically, receiver bacteria collectively interact with sender bacteria for decision-making through quorum sensing. Input patterns formed by chemical inducers activate senders to produce signaling molecules at varying levels. These levels, which act as weights, are programmed by tuning the sender promoter strength Furthermore, a gradient descent based algorithm that enables weights optimization was developed. Weights were experimentally examined for recognizing 3 × 3-bit pattern.

In Vitro 3D Cell-Cultured Arterial Models for Studying Vascular Drug Targeting Under Flow

The use of three-dimensional (3D) models of human arteries, which are designed with the correct dimensions and anatomy, enables the proper modeling of various important processes in the cardiovascular system. Recently, although several biological studies have been performed using such 3D models of human arteries, they have not been applied to study vascular targeting. This paper presents a new method to fabricate real-sized, reconstructed human arterial models using a 3D printing technique, line them with human endothelial cells (ECs), and study particle targeting under physiological flow. These models have the advantage of replicating the physiological size and conditions of blood vessels in the human body using low-cost components. This technique may serve as a new platform for studying and understanding drug targeting in the cardiovascular system and may improve the design of new injectable nanomedicines. Moreover, the presented approach may provide significant tools for the study of targeted delivery of different agents for cardiovascular diseases under patient-specific flow and physiological conditions.

Fabrication of spectrally sharp Si-based dielectric resonators: combining etaloning with Mie resonances

We use low-resolution optical lithography joined with solid state dewetting of crystalline, ultra-thin silicon on insulator (c-UT-SOI) to form monocrystalline, atomically smooth, silicon-based Mie resonators in well-controlled large periodic arrays. The dewetted islands have a typical size in the 100 nm range, about one order of magnitude smaller than the etching resolution. Exploiting a 2 µm thick SiO₂ layer separating the islands and the underlying bulk silicon wafer, we combine the resonant modes of the antennas with the etalon effect. This approach sets the resonance spectral position and improves the structural colorization and the contrast between scattering maxima and minima of individual resonant antennas. Our results demonstrate that templated dewetting enables the formation of defect-free, faceted islands that are much smaller than the nominal etching resolution and that an appropriate engineering of the substrate improves their scattering properties. These results are relevant to applications in spectral filtering, structural color and beam steering with all-dielectric photonic devices.

Association between socioeconomic indicators and geographic distribution of vestibular schwannomas in West Scotland: a 15-year review

OBJECTIVE

Socioeconomic risk factors may contribute to geographic variation in diseases, but studies are limited due to lack of large available cohorts.

METHOD

A geographic analysis was performed of the association between socioeconomic risk factors and the distribution of vestibular schwannomas in adults diagnosed with sporadic vestibular schwannomas through the National Health Services in the West of Scotland from 2000 to 2015.

RESULTS

A total of 511 sporadic vestibular schwannomas were identified in a population of over 3.1 million. Prevalence of vestibular schwannomas were lowest in cases with good health (-0.64, 95 per cent confidence interval: -0.93,-0.38; p = 0.002) and level 1 qualifications (-0.562, 95 per cent confidence interval: -0.882 to -0.26; p = 0.01). However, these risk factors did not demonstrate consistent linearity of correlations. Prevalence was lower in people originating from European Union accession countries from April 2001 to March 2011 (-0.63, 95 per cent confidence interval: -0.84 to -0.43; p = 0.002). No correlation between distribution of vestibular schwannomas and socioeconomic risk factors met our threshold criteria (± 0.7).

CONCLUSION

This study demonstrated that there is little variation in distribution of vestibular schwannomas by socioeconomic risk factors.

PPARβ/δ-dependent MSC metabolism determines their immunoregulatory properties

Mesenchymal stem cell (MSC)-based therapy is being increasingly considered a powerful opportunity for several disorders based on MSC immunoregulatory properties. Nonetheless, MSC are versatile and plastic cells that require an efficient control of their features and functions for their optimal use in clinic. Recently, we have shown that PPARβ/δ is pivotal for MSC immunoregulatory and therapeutic functions. However, the role of PPARβ/δ on MSC metabolic activity and the relevance of PPARβ/δ metabolic control on MSC immunosuppressive properties have never been addressed. Here, we demonstrate that PPARβ/δ deficiency forces MSC metabolic adaptation increasing their glycolytic activity required for their immunoregulatory functions on Th1 and Th17 cells. Additionally, we show that the inhibition of the mitochondrial production of ATP in MSC expressing PPARβ/δ, promotes their metabolic switch towards aerobic glycolysis to stably enhance their immunosuppressive capacities significantly. Altogether, these data demonstrate that PPARβ/δ governs the immunoregulatory potential of MSC by dictating their metabolic reprogramming and pave the way for enhancing MSC immunoregulatory properties and counteracting their versatility.

Targeting functionalized nanoparticles to activated endothelial cells under high wall shear stress

Local inflammation of the endothelium is associated with a plethora of cardiovascular diseases. Vascular-targeted carriers (VTCs) have been advocated to provide focal effective therapeutics to these disease sites. Here, we examine the design of functionalized nanoparticles (NPs) as VTCs that can specifically localize at an inflamed vessel wall under pathological levels of high shear stress, associated for example with clinical (or in vivo) conditions of vascular narrowing and arteriogenesis. To test this, carboxylated fluorescent 200 nm polystyrene particles were functionalized with ligands to activated endothelium, that is, an E-selectin binding peptide (Esbp), an anti ICAM-1 antibody, or using a combination of both. The functionalized NPs were investigated in vitro using microfluidic models lined with inflamed (TNF-α stimulated) and control endothelial cells (EC). Specifically, their adhesion was monitored under different relevant wall shear stresses (i.e., 40-300 dyne/cm2) via real-time confocal microscopy. Experiments reveal a significantly higher specific adhesion of the examined functionalized NPs to activated EC for the window of examined wall shear stresses. Moreover, particle adhesion correlated with the surface coating density whereby under high surface coating (i.e., ~10,000 molecule/particle), shear-dependent particle adhesion increased significantly. Altogether, our results show that functionalized NPs can be designed to target inflamed endothelial cells under high shear stress. Such VTCs underscore the potential for attractive avenues in targeting drugs to vasoconstriction and arteriogenesis sites.

Cell-Based Regenerative Endodontics for Treatment of Periapical Lesions: A Randomized, Controlled Phase I/II Clinical Trial

A randomized controlled phase I/II clinical trial was designed to evaluate the safety and efficacy of encapsulated human umbilical cord mesenchymal stem cells in a plasma-derived biomaterial for regenerative endodontic procedures (REPs) in mature permanent teeth with apical lesions. The trial included 36 patients with mature incisors, canines, or mandibular premolars showing pulp necrosis and apical periodontitis. Patients were randomly and equally allocated between experimental (REP) or conventional root canal treatment (ENDO) groups. On the first visit, cavity access and mechanical preparation of the root canal were performed. Calcium hydroxide medication was used, and the cavity was sealed. Three weeks later, patients were treated following their assigned protocol of ENDO or REP. Clinical follow-up examinations were performed at 6 and 12 mo. Categorical variables were evaluated by Fisher's exact test. Quantitative variables were compared using the Mann-Whitney test. The evolution over time of the percentage of perfusion units and the dimensions of lesion and cortical compromise were explored. After the 12-mo follow-up, no adverse events were reported, and the patients showed 100% clinical efficacy in both groups. Interestingly, in the REP group, the perfusion unit percentage measured by laser Doppler flowmetry revealed an increase from 60.6% to 78.1% between baseline and 12-mo follow-up. Sensitivity tests revealed an increase of the positive pulp response in the REP group at 12-mo follow-up (from 6% to 56% on the cold test, from 0% to 28% on the hot test, and from 17% to 50% on the electrical test). We present the first clinical safety and efficacy evidence of the endodontic use of allogenic umbilical cord mesenchymal stem cells encapsulated in a plasma-derived biomaterial. The innovative approach, based on biological principles that promote dentin-pulp regeneration, presents a promising alternative for the treatment of periapical pathology (ClinicalTrials.gov NCT03102879).

Assessing and visualising hazard impacts to enhance the resilience of Critical Infrastructures to urban flooding

The design, construction and maintenance of Critical Infrastructures (CI) is commonly based on standards that are rigorous, so as to withstand any climate or weather-linked pressures. However, due to climate change, climate characteristics may shift, resulting in increased frequency/magnitude of potential failures, or exposure to new unknown risks. As vital components for the normal functioning of modern societies, the resilience of CIs under climate stressors encompasses their structural integrity, their operational elements, and their capacity to maximize business output. In this work, we propose an integrated and participatory methodological approach to enhance the resilience of interconnected CIs to urban flooding under climate change, by assessing the risk and introducing adaptation measures. The main objectives of the proposed methodology and approach are: (i) to provide scientific evidence for better understanding of how future climate regimes might affect normal operation of interconnected CI in urban areas during their lifespan; (ii) to assess the cost-effectiveness of different adaptation measures; (iii) to involve local stakeholders and operators in the co-design of the approach, as well as the assessment and the evaluation of adaptation measures; (iv) to combine computational modelling with advanced 3D visualisation techniques for effectively engaging stakeholders in decision making; (v) to include risk assessment and damage functions co-designed by end-users and local stakeholders; (vi) to integrate all of the aforementioned components in a specifically designed cloud platform as a Decision Support System for end-users, (vii) to validate the DSS by the end users and local stakeholders. The paper presents the computational background and tools. Additionally, it describes a Case Study in Torbay, UK, where the full methodology and the proposed participatory approach have been applied, with all the specifics, i.e., the scenarios of extreme flooding, the numerical and visualisation results, the response of the stakeholders and the evaluation of selected adaptation measures.

The multi-spectral line-polarization MSE system on Alcator C-Mod

A multi-spectral line-polarization motional Stark effect (MSE-MSLP) diagnostic has been developed for the Alcator C-Mod tokamak wherein the Stokes vector is measured in multiple wavelength bands simultaneously on the same sightline to enable better polarized background subtraction. A ten-sightline, four wavelength MSE-MSLP detector system was designed, constructed, and qualified. This system consists of a high-throughput polychromator for each sightline designed to provide large étendue and precise spectral filtering in a cost-effective manner. Each polychromator utilizes four narrow bandpass interference filters and four custom large diameter avalanche photodiode detectors. Two filters collect light to the red and blue of the MSE emission spectrum while the remaining two filters collect the beam pi and sigma emission generated at the same viewing volume. The filter wavelengths are temperature tuned using custom ovens in an automated manner. All system functions are remote controllable and the system can be easily retrofitted to existing single-wavelength line-polarization MSE systems.

PPARβ/δ directs the therapeutic potential of mesenchymal stem cells in arthritis

OBJECTIVES

To define how peroxisome proliferator-activated receptor (PPAR) β/δ expression level in mesenchymal stem cells (MSCs) could predict and direct both their immunosuppressive and therapeutic properties. PPARβ/δ interacts with factors such as nuclear factor-kappa B (NF-κB) and regulates the expression of molecules including vascular cell adhesion molecule (VCAM)-1 and intercellular adhesion molecule (ICAM)-1. Since these molecules are critical for MSC function, we investigated the role of PPARβ/δ on MSC immunosuppressive properties.

METHODS

We either treated human MSCs (hMSCs) with the irreversible PPARβ/δ antagonist (GSK3787) or derived MSCs from mice deficient for PPARβ/δ (PPARβ/δ^-/- MSCs). We used the collagen-induced arthritis (CIA) as model of immune-mediated disorder and the MSC-immune cell coculture assays.

RESULTS

Modulation of PPARβ/δ expression in hMSCs either using GSK3787 or hMSCs from different origin reveals that MSC immunosuppressive potential is inversely correlated with Ppard expression. This was consistent with the higher capacity of PPARβ/δ^-/- MSCs to inhibit both the proliferation of T lymphocytes, in vitro, and arthritic development and progression in CIA compared with PPARβ/δ^+/+ MSCs. When primed with proinflammatory cytokines to exhibit an immunoregulatory phenotype, PPARβ/δ^-/- MSCs expressed a higher level of mediators of MSC immunosuppression including VCAM-1, ICAM-1 and nitric oxide (NO) than PPARβ/δ^+/+ MSCs. The enhanced NO₂ production by PPARβ/δ^-/- MSCs was due to the increased retention of NF-κB p65 subunit on the κB elements of the inducible nitric oxide synthase promoter resulting from PPARβ/δ silencing.

CONCLUSIONS

Our study is the first to show that the inhibition or knockdown of PPARβ/δ in MSCs primes their immunoregulatory functions. Thus, the regulation of PPARβ/δ expression provides a new strategy to generate therapeutic MSCs with a stable regulatory phenotype.

Adolescents with severe obesity: outcomes of participation in an intensive obesity management programme

BACKGROUND

Most interventions for childhood obesity are randomized controlled studies. Less is known about the effectiveness of clinical obesity programmes.

OBJECTIVE

To assess outcomes in adolescents participating in the SickKids Team Obesity Management Program (STOMP) vs. a comparison group of obese adolescents.

METHODS

Severely obese adolescents (n = 75) in STOMP (15.1 ± 1.8 years, body mass index [BMI] 44.8 ± 7.8 kg m(-2) ) were compared with adolescents (n = 41) not in the programme (14.9 ± 2.0 years, BMI 34.5 ± 8.0 kg m(-2) ). Outcomes were change in BMI, cardiometabolic, psychological and health behaviour measures.

RESULTS

At 6 months, STOMP patients' BMI was unchanged (0.08 ± 0.3; P = 0.79) and they reported improvements in quality of life and depression (-3.6 ± 1.4; P = 0.009), and increases in measures of readiness to change (RTC). Between-group differences in change between 0 and 6 months, in favour of STOMP patients, were observed for homeostatic measurement assessment-insulin resistance (HOMA-IR; -2.7 ± 1.0; P = 0.007), depression scores (-3.5 ± 1.7; P = 0.04), diet-RTC (0.6 ± 0.2; P < 0.001) and physical activity (1.7 ± 0.9; P = 0.05). At 12 months, STOMP patients increased BMI (0.8 ± 0.5; P = 0.07), but they exhibited decreased waist circumference (-7.4 ± 2.1 cm; P = 0.001) and HOMA-IR (-1.9 ± 0.6; P = 0.002). Between-group differences in change between 0 and 12 months, in favour of STOMP patients, were observed for waist circumference (-5.9 ± 2.4 cm; P = 0.01), HOMA-IR (-2.9 ± 0.7; P < 0.001) and diet-RTC (0.9 ± 0.2; P < 0.001).

CONCLUSIONS

STOMP participants did not experience a significant reduction in BMI but did have improvements in cardiometabolic, psychological and health behaviour outcomes. Evaluation of paediatric clinical obesity programmes using multiple measures is essential to understanding real-world outcomes.