Key Contributors to Signal Generation in Frequency Mixing Magnetic Detection (FMMD): An In Silico Study.

Frequency mixing magnetic detection (FMMD) is a sensitive and selective technique to detect magnetic nanoparticles (MNPs) serving as probes for binding biological targets. Its principle relies on the nonlinear magnetic relaxation dynamics of a particle ensemble interacting with a dual frequency external magnetic field. In order to increase its sensitivity, lower its limit of detection and overall improve its applicability in biosensing, matching combinations of external field parameters and internal particle properties are being sought to advance FMMD. In this study, we systematically probe the aforementioned interaction with coupled Néel-Brownian dynamic relaxation simulations to examine how key MNP properties as well as applied field parameters affect the frequency mixing signal generation. It is found that the core size of MNPs dominates their nonlinear magnetic response, with the strongest contributions from the largest particles. The drive field amplitude dominates the shape of the field-dependent response, whereas effective anisotropy and hydrodynamic size of the particles only weakly influence the signal generation in FMMD. For tailoring the MNP properties and parameters of the setup towards optimal FMMD signal generation, our findings suggest choosing large particles of core sizes dC>25 nm with narrow size distributions (σ<0.1) to minimize the required drive field amplitude. This allows potential improvements of FMMD as a stand-alone application, as well as advances in magnetic particle imaging, hyperthermia and magnetic immunoassays.

Tipless transseptal cannula concept combines improved hemodynamic properties and risk-reduced placement: An in silico proof-of-concept.

As a leading cause of death worldwide, heart failure is a serious medical condition in which many critically ill patients require temporary mechanical circulatory support (MCS) as a bridge-to-recovery or bridge-to-decision. In many cases, the TandemHeart system is used to unload the left heart by draining blood from the left atrium (LA) to the femoral artery via a transseptal multistage cannula. However, even though the correct positioning of the cannula is crucial for a safe treatment, the long cannula tip currently used in transseptal cannulas complicates positioning, making the cannula vulnerable to displacement during MCS. To overcome these limitations, we propose the development of a new tipless transseptal cannula with improved hemodynamic properties. We discuss the tipless cannula concept by comparing it to the common multistage cannula concept using computational fluid dynamics simulations and assess the flow field in the LA, the wall shear stresses (WSS), and the pressure loss. Across the two distinct time points of end-systole and end-diastole and two drainage flow rates of 3.5 and 5.0 L/min, we find a more homogeneous inlet flow pattern for the tipless cannula concept, accompanied by a remarkably reduced area of platelet-activating WSS (up to 10-times smaller area compared to the multistage cannula). Moreover, pressure loss is up to 14.5% lower in the tipless cannula concept, confirming overall improved hemodynamic properties of the tipless cannula concept. Finally, a diameter-dependent study reveals that lower WSS and pressure losses can be further reduced by large-lumen designs for any simulation setting. Overall, our results suggest that a tipless cannula concept remedies the crucial disadvantages of a long-tip multistage cannula by reducing the risk of misplacement, and it furthermore promotes optimized hemodynamics. With this successful proof-of-concept, we underscore the potential for and encourage the realization of further experimental investigations regarding the development of a tipless transseptal cannula for MCS.

Size-isolation of superparamagnetic iron oxide nanoparticles improves MRI, MPI and hyperthermia performance.

Superparamagnetic iron oxide nanoparticles (SPION) are extensively used for magnetic resonance imaging (MRI) and magnetic particle imaging (MPI), as well as for magnetic fluid hyperthermia (MFH). We here describe a sequential centrifugation protocol to obtain SPION with well-defined sizes from a polydisperse SPION starting formulation, synthesized using the routinely employed co-precipitation technique. Transmission electron microscopy, dynamic light scattering and nanoparticle tracking analyses show that the SPION fractions obtained upon size-isolation are well-defined and almost monodisperse. MRI, MPI and MFH analyses demonstrate improved imaging and hyperthermia performance for size-isolated SPION as compared to the polydisperse starting mixture, as well as to commercial and clinically used iron oxide nanoparticle formulations, such as Resovist® and Sinerem®. The size-isolation protocol presented here may help to identify SPION with optimal properties for diagnostic, therapeutic and theranostic applications.

Modeling of magnetoliposome uptake in human pancreatic tumor cells in vitro.

The internalization kinetics resulting from magnetic nanoparticle interactions with tumor cells play an important role in nanoparticle-based cancer treatment efficiency. Here, the uptake kinetics of magnetoliposomes (ML) into human pancreatic tumor cells (MiaPaCa-2 and BxPC-3) are quantified using magnetic particle spectrometry. A comparison to the uptake kinetics for healthy L929 cells is given. The experimental results are used for the development of an uptake kinetics model describing the three relevant internalization processes: ML adsorption to the cell membrane, endo- and exocytosis. By fitting of experimental data, the rate constant of each internalization process is determined enabling the prediction of internalized ML at any incubation time. After seven hours incubation time, MiaPaCa-2 internalized three times more ML than BxPC-3 and L929 cells even though their ML adsorption rate constants were nearly the same. As the interaction of the ML with the cell membrane is non-specific, the uptake kinetics mirror the individual cell response to ML internalization. With a new mathematical term to cover the exocytosis contribution to the overall internalization process, the extended uptake kinetics model offers new possibilities to analyze the specific internalization mechanism for other nanoparticle and cell types.

Rationale, design, and methods of a non-interventional study to establish safety, effectiveness, quality of life, cognition, health-related and work capacity data on Alemtuzumab in multiple sclerosis patients in Germany (TREAT-MS).

BACKGROUND: Alemtuzumab, a humanized monoclonal antibody directed against the cell surface glycoprotein CD52, is licensed in Europe since October 2013 as treatment for adult patients with active relapsing-remitting multiple sclerosis (RRMS). In three randomized, rater-blinded active comparator clinical trials studies, alemtuzumab administered in two annual courses, had superior efficacy as compared to subcutaneous interferon beta-1a, and durable efficacy over 5 years in an extension study with a manageable safety profile in RRMS patients. Data on the utilization and the outcomes of alemtuzumab under clinical practice conditions are limited. METHODS: Here we describe the rationale, design and methods of the TREAT-MS study (non-interventional long-Term study foR obsErvAtion of Treatment with alemtuzumab in active relapsing-remitting MS). DISCUSSION: TREAT-MS is a prospective, multicenter, non-interventional, long-term study to collect data on safety, effectiveness, quality of life, cognition and other aspects from 3200 RRMS patients treated with alemtuzumab under the conditions of real-world clinical practice in Germany. TRIAL REGISTRATION: As non-interventional trial in Germany.

Alemtuzumab in a Large Real-Life Cohort: Interim Baseline Data of the TREAT-MS Study.

The non-interventional long-Term study foR obsErvAtion of Treatment with alemtuzumab in active relapsing-remitting MS (TREAT-MS) study collects the so far largest real-life cohort regarding utilization, long-term effectiveness, and safety of alemtuzumab, a humanized monoclonal antibody directed against the cell surface glycoprotein CD52, in adult patients with active relapsing-remitting multiple sclerosis (RRMS). An interim analysis of baseline parameters at inclusion of a non-interventional real-world study about alemtuzumab in Germany including previous multiple sclerosis (MS) medication utilization, MS activity, severity, and duration, as well as comorbidities was performed. Of the 883 patients, 71.6% were women. Mean age was 35.7 ± 9.2 years, time since first MS symptoms (=disease duration) is 8.0 ± 6.8 years, and Expanded Disability Status Scale (EDSS) is 2.7 ± 1.8 points (range, 0.0-7.5 points). The number of relapses in the 12 and 24 months prior to inclusion were 1.6 ± 1.2 and 2.2 ± 1.8, respectively. Of the patients, 14.4% were treatment naive, while for the majority, a wide spectrum of MS disease-modifying treatments (DMTs) and treatment sequences were documented. Overall, interferon beta (IFN-beta) was reported most frequently (52.4%), followed by fingolimod (35.2%), natalizumab (34.9%), and glatiramer acetate (28.9%). Patients with longer disease duration and higher EDSS had a higher number of previous DMTs. Compared to the pivotal phase 2/3 studies, RRMS patients starting alemtuzumab treatment had a longer disease duration in real-world conditions. There was variety of different treatment sequences before the final switch to alemtuzumab. In the future, linking these treatment sequences or other baseline characteristics with effectiveness and safety outcomes might be useful to support treatment decisions. Registered at Paul-Ehrlich-Institut under NIS 281.

Comparative Modeling of Frequency Mixing Measurements of Magnetic Nanoparticles Using Micromagnetic Simulations and Langevin Theory.

Dual frequency magnetic excitation of magnetic nanoparticles (MNP) enables enhanced biosensing applications. This was studied from an experimental and theoretical perspective: nonlinear sum-frequency components of MNP exposed to dual-frequency magnetic excitation were measured as a function of static magnetic offset field. The Langevin model in thermodynamic equilibrium was fitted to the experimental data to derive parameters of the lognormal core size distribution. These parameters were subsequently used as inputs for micromagnetic Monte-Carlo (MC)-simulations. From the hysteresis loops obtained from MC-simulations, sum-frequency components were numerically demodulated and compared with both experiment and Langevin model predictions. From the latter, we derived that approximately 90% of the frequency mixing magnetic response signal is generated by the largest 10% of MNP. We therefore suggest that small particles do not contribute to the frequency mixing signal, which is supported by MC-simulation results. Both theoretical approaches describe the experimental signal shapes well, but with notable differences between experiment and micromagnetic simulations. These deviations could result from Brownian relaxations which are, albeit experimentally inhibited, included in MC-simulation, or (yet unconsidered) cluster-effects of MNP, or inaccurately derived input for MC-simulations, because the largest particles dominate the experimental signal but concurrently do not fulfill the precondition of thermodynamic equilibrium required by Langevin theory.

Teriflunomide in relapsing-remitting multiple sclerosis: outcomes by age and pre-treatment status.

BACKGROUND AND AIMS: To investigate effectiveness and safety of teriflunomide (14 mg once daily) in association with age and pre-treatment in unselected MS patients. METHODS: Prespecified analysis of a non-interventional, prospective, real-world study in Germany. RESULTS: A total of 558 (49.5%) patients were above 45 years old, and 593 patients (52.6%) had been pre-treated within 6 months prior to teriflunomide. Baseline Expanded Disability Status Scale (EDSS) was higher with older age, with lower number of relapses. Relapse rate decreased in all age groups, and in both treatment-naïve (0.82 ± 0.73 at baseline; 0.25 ± 0.55 under teriflunomide) and pre-treated (from 0.48 ± 0.76; 0.22 ± 0.50) patients after 12 months compared with the year before teriflunomide initiation. EDSS remained stable in patients of all age groups as well as in therapy-naïve and pre-treated patients over 24 months. The percentage of patients with adverse events (AEs) ranged between 29.2% (age group >25-35) and 38.9% (age group >55-65), with an increased discontinuation rate (most commonly due to diarrhoea, alopecia and nausea) in the higher age groups. AE rates were lower in pre-treated compared with treatment-naïve patients. CONCLUSION: Overall, patients of all age groups including older patients, and irrespective of pre-treatment, benefit from teriflunomide treatment in routine clinical practice. REGISTRATION: BfArM public study database number 2075.

Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input.

Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti2CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.

Real-life outcomes of teriflunomide treatment in patients with relapsing multiple sclerosis: TAURUS-MS observational study.

BACKGROUND: Teriflunomide is a once-daily oral immunomodulatory agent approved for the treatment of relapsing-remitting multiple sclerosis (MS). We aimed to obtain data on the effectiveness, tolerability, and subject satisfaction with teriflunomide (Aubagio®) under clinical practice conditions in unselected MS patients. METHODS: This work was a non-interventional, prospective, longitudinal, observational study in 307 sites in Germany. RESULTS: A total of 1128 patients were eligible for the efficacy analysis [67.5% female; mean age (± standard deviation) 44.9 ± 9.7 years, range 20-73 years]. Time since first MS symptoms was 10.6 ± 8.2 years, and time since MS diagnosis was 8.9 ± 7.6 years. Expanded Disability Status Scale (EDSS) score at inclusion was 2.3 ± 1.5 (70.4% with score < 3.5). The mean observation period was 16.3 ± 9.1 months. A total of 75.2% had received previous disease-modifying therapies (DMTs) at any time. Of these patients, 504 (44.7%) received no DMT within 6 months of study entry, 593 patients (52.6%) had DMT discontinued prior to study entry [glatiramer acetate in 10.6%, subcutaneous interferon-beta 1a (IFNß-1a) in 9.3%, intramuscular IFNß-1a or IFNß-1b in 6.6% each, azathioprine oral in 0.4%, other in 7.3%, last medication not known in 12.0%]. The mean annualized relapse rate decreased from 0.87 in the 24 months prior to study entry to 0.35 in the 24 months after study entry (n = 468; p ⩽ 0.001). EDSS and Fatigue Severity Scale remained stable. In patients who received previous MS treatments, Treatment Satisfaction Questionnaire (TSQM-9) values (maximum = 100), for the observation at 24 months improved by 8.1 points for effectiveness, 17.0 points for convenience, and 15.3 points for global satisfaction (p ⩽ 0.001 each, compared with study entry). In the safety cohort (n = 1139), the proportion of patients with adverse events (AEs) of any severity was 35.8%, and with serious events 13.0%. The most frequently reported AEs were diarrhea (n = 55), followed by MS relapse (n = 48), hair thinning (n = 38), and viral upper respiratory tract infection (n = 31). CONCLUSIONS: Relapse rate was halved during the observation period in comparison with the same time period before study entry. Patient satisfaction with teriflunomide was high in this real-world observation of patients, the majority of whom switched from other DMTs. The safety and tolerability profile of teriflunomide was similar to that reported in previous clinical trials.

Combining Bulk Temperature and Nanoheating Enables Advanced Magnetic Fluid Hyperthermia Efficacy on Pancreatic Tumor Cells.

Many efforts are made worldwide to establish magnetic fluid hyperthermia (MFH) as a treatment for organ-confined tumors. However, translation to clinical application hardly succeeds as it still lacks of understanding the mechanisms determining MFH cytotoxic effects. Here, we investigate the intracellular MFH efficacy with respect to different parameters and assess the intracellular cytotoxic effects in detail. For this, MiaPaCa-2 human pancreatic tumor cells and L929 murine fibroblasts were loaded with iron-oxide magnetic nanoparticles (MNP) and exposed to MFH for either 30 min or 90 min. The resulting cytotoxic effects were assessed via clonogenic assay. Our results demonstrate that cell damage depends not only on the obvious parameters bulk temperature and duration of treatment, but most importantly on cell type and thermal energy deposited per cell during MFH treatment. Tumor cell death of 95% was achieved by depositing an intracellular total thermal energy with about 50% margin to damage of healthy cells. This is attributed to combined intracellular nanoheating and extracellular bulk heating. Tumor cell damage of up to 86% was observed for MFH treatment without perceptible bulk temperature rise. Effective heating decreased by up to 65% after MNP were internalized inside cells.