Cell Preparation Protocols Research Articles

Defining an Optimized Workflow for Enriching and Analyzing Residual Tumor Populations Using Intracellular Markers

Tumor relapse is well-recognized to arise from treatment-resistant residual populations. Strategies enriching such populations for in-depth downstream analyses focus on tumor-specific surface markers; however, enrichment using intracellular biomarkers remains challenging. Using B-cell lymphoma as an exemplar, we demonstrate feasibility to enrich BCL2high populations, a surrogate marker for t(14;18)+ lymphomas, for use in downstream applications. Different fixation protocols were assessed for impact on antibody expression and RNA integrity; glyoxal fixation demonstrated superior results regarding minimal effects on surface and intracellular expression, and RNA quality, compared to alternative fixatives evaluated. Furthermore, t(14;18)+ B-cells were effectively detected using intracellular BCL2 over-expression to facilitate tumor cell enrichment. Tumor cell populations were enriched using the cellenONE F1.4 single cell sorting platform, which detected and dispensed BCL2high-expressing cells directly into library preparation reagents for transcriptome analyses. Sorted glyoxal-fixed cells generated good quality sequencing libraries, with high concordance between live and fixed single cell transcriptomic profiles, discriminating cell populations predominantly on B-cell biology. Overall, we successfully develop a proof-of-concept workflow employing a robust cell preparation protocol for intracellular markers combined with cell enrichment using the cellenONE platform, providing an alternative to droplet-based technologies when cellular input is low or requires prior enrichment to detect rare populations. This workflow has wider prognostic and therapeutic potential to study residual cells in a pan-cancer setting.

Development of Long Duration Button Cell Test Stands and Testing Protocols

In order to support the accelerated testing of the H2New consortium, long term repeatable cell testing is a necessary step. Cross-lab comparability and long duration tests are needed in order to establish a baseline degradation. The use of long-term testing with existing test stands and techniques that were developed primarily for material screening led to modifications to better suit long-term testing.The stability of sealing of cells and operation of cells with the ability to endure a thermal cycle is a key point of interest in the long duration button cell testing. Cells with the ability to maintain performance unplanned power cycles are critical to the long-term understanding of button cells. System upgrades to improve long term button cell system reliability include the following: back-up power systems, thermal cycle stable glass, current collector attachment improvement, power monitoring, and in-operando cell leakage monitoring. The system modifications to identify and correct the most common causes of long-term button cell test failures are discussed. Discussions and lessons learned from cell test stand development and cell preparation protocols are presented.

Impact of Coin Cell Preparation and Testing Protocols on Coulombic Efficiency Measurements

The lithium (Li) metal anode holds great promise for high energy-density rechargeable batteries due to its high gravimetric capacity (3860 mAh/g), an order of magnitude larger than graphite at a similar electrochemical potential (-3.040 V vs SHE for Li). However, limited Coulombic efficiency (CE), caused by the thermodynamic instability of conventional Li-ion electrolyte solvents and salts with Li that leads to unstable solid-electrolyte interphase (SEI) during repeated plating and stripping, has hindered the commercialization of Li metal batteries. Research efforts have focused on tuning the electrolyte composition to promote a stable SEI that simultaneously blocks continuous side reactions and electronic conductivity while facilitating Li+ transport [1], with coin cells being by far the most preferred form factor for evaluating these electrolyte designs.Coin cells enable accessible and rapid testing of diverse electrolyte compositions. Their preparation requires no specialized equipment beyond an inert chemical environment, a crimping mechanism to seal the cell, and modest quantities of Li metal (~50 - 100 μm thickness) and electrolyte (~50 - 100 μL volume) [2]. Despite these attractive features, the procedures for preparing and techniques for measuring CE in coin cells are not fully standardized. In this presentation, we examine the impact on measured CE from preparation and testing procedures, including the internal coin cell stack consisting of components such as the electrodes, current collectors / spacers, and separators, and the cycling protocol. While the cycling protocol and cycling capacity are known to affect capacity loss mechanisms in Li metal batteries [3], we show that variances in CE can additionally be attributed to specific details of cell preparation. In particular, the working electrode area and stack thickness affect the pressure magnitude and uniformity inside the cell. We demonstrate that standardizing the procedures for preparing coin cells reduces variation due to nonuniformities and edge effects and hence improves the reproducibility of CE measurements.[1] Hobold, G. M., et al. Nature Energy 2021 6 (10), 951-960.[2] Xiao, J., et al. Nature Energy 2020 5 (8), 561-568.[3] Adams, B. D., et al. Advanced Energy Materials 2018 8 (7), 1702097. Figure 1

Improved MALDI-TOF MS Identification of Mycobacterium tuberculosis by Use of an Enhanced Cell Disruption Protocol.

Mycobacterium tuberculosis is the microorganism that causes tuberculosis, a disease affecting millions of people worldwide. Matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) is a fast, reliable, and cost-effective method for microorganism identification which has been used for the identification of Mycobacterium spp. isolates. However, the mycobacteria cell wall is rich in lipids, which makes it difficult to obtain proteins for MALDI-TOF MS analysis. In this study, two cell preparation protocols were compared: the MycoEx, recommended by MALDI-TOF instrument manufacturer Bruker Daltonics, and the MycoLyser protocol described herein, which used the MagNA Lyser instrument to enhance cell disruption with ethanol. Cell disruption and protein extraction steps with the two protocols were performed using the Mycobacterium tuberculosis H37Rv strain, and the MALDI-TOF MS results were compared. The MycoLyser protocol allowed for improved Biotyper identification of M. tuberculosis since the log(score) values obtained with this protocol were mostly ≥ 1.800 and significantly higher than that underwent MycoEx processing. The identification reliability was increased as well, considering the Bruker criteria. In view of these results, it is concluded that the MycoLyser protocol for mycobacterial cell disruption and protein extraction improves the MALDI-TOF MS method's efficacy for M. tuberculosis identification.

Reliable cell preparation protocol for Raman imaging to effectively differentiate normal leukocytes and leukemic blasts

Leukemias are a remarkably diverse group of malignancies originating from abnormal progenitor cells in the bone marrow. Leukemia subtypes are classified according to the cell type that has undergone neoplastic transformation using demanding and time-consuming methods. Alternative is Raman imaging that can be used both for living and fixed cells. However, considering the diversity of leukemic cell types and normal leukocytes, and the availability of different sample preparation protocols, the main objective of this work was to verify them for leukemia and normal blood cell samples for Raman imaging.The effect of glutaraldehyde (GA) fixation in a concentration gradient (0.1 %, 0.5 %, and 2.5 % GA) on the molecular structure of T-cell acute lymphoblastic leukemia (T-ALL) and peripheral blood mononuclear cells (PBMCs) was verified. Changes in the secondary structure of proteins within cells were indicated as the main effect of fixation, as shown by an increase in band intensity at 1041 cm−1, characteristic for in-plane δ(CH) deformation in phenylalanine (Phe).Different sensitivity of mononuclear and leukemic cells to fixation was observed. While the 0.1 % concentration of GA was too low to preserve the cell structure for an extended period of time, a GA concentration of 0.5 % seemed optimal for both normal and malignant cells. Chemical changes in PBMCs samples stored for 11 days were also investigated, which manifested in numerous modifications in the secondary structure of proteins and the content of nucleic acids. The impact of cell preculturing for 72 h after unbanking was verified, and there was no significant effect on the molecular structure of cells fixed with 0.5 % GA. In summary, the developed protocol for the preparation of samples for Raman imaging allows for the effective differentiation of fixed normal leukocytes from malignant T lymphoblasts.

Quiescence of Human Monocytes after Affinity Purification: A Novel Method Apt for Monocyte Stimulation Assays.

Several methods to isolate monocytes from whole blood have been previously published, with different advantages and disadvantages. For the purpose of cytokine release assessment upon external stimulation, the use of monocyte preparations consisting of non-activated cells is prerequisite. Affinity-isolated monocyte preparations from peripheral blood mononuclear cells (PBMCs), obtained via positive or negative selection using magnetic beads, released pro-inflammatory cytokines such as TNF-α and IL-6 even without adding external stimuli, hindering any assessment of an effect of bacterial lipoproteins on cell stimulation. Hence, the cell preparation protocol was modified by adding a quiescence step on repellent surface culture plates, dampening any monocyte pre-activation. This protocol now provides a robust method to prepare silent yet fully activatable, pure monocyte populations for further use in stimulus-elicited activation experiments.

Addition of Popular Exogenous Antioxidant Agent, PBN, to Culture Media May Be an Important Step to Optimization of Myogenic Stem/Progenitor Cell Preparation Protocol

The aim of the study was to modify human skeletal muscle-derived stem/progenitor cells (SkMDS/PCs) and demonstrate the optimal cell preparation protocol for application in post-infarction hearts. We used conditioned SkMDS/PC culture medium with α-phenyl-N-tert-butyl nitrone (PBN). SkMDS/PCs were cultured under hypoxic conditions and the results were compared to the standard ones. We observed a significant increase of CD-56 positive phenotypic marker the ability to form functional myotubes, increase in the proportion of young cells in cell primary suspensions, and a decrease in the percentage of apoptotic cells among PBN-conditioned cells in normoxia an hypoxia. We also observed significantly higher levels of SOD3 expression; maintained expression of SOD1, SOD2, and CAT; a higher level of BCL2 gene expression; and a rather significant decrease in Hsp70 gene expression in PBN-conditioned SkMDS/PCs compared to the WT population under hypoxic conditions. In addition, significant increase of myogenic genes expression was observed after PBN addition to culture medium, compared to WT population under hypoxia. Interestingly, PBN addition significantly increased the lengths of telomeres under hypoxia. Based on the data obtained, we can postulate that PBN conditioning of human SkMDS/PCs could be a promising step in improving myogenic cell preparation protocol for pro-regenerative treatment of post-infarction hearts.

1190. Dual-Plasmid Technology for Precision Genome Editing in Staphylococcus aureus

BackgroundGenetic manipulation of Staphylococcus aureus (both methicillin sensitive S. aureus, MSSA, and methicillin resistant S. aureus, MRSA) poses a technical challenge due to poor transformation efficiency, limited endogenous DNA repair activity, lineage-specific methylation patterns and intrinsic resistance to common selectable markers.MethodsTo address transformation efficiency we have optimized electrocompetent cell preparation and electroporation protocols for staphylococci. Further, we have improved a CRISPR counterselection platform that delivers a heterologous ssDNA recombinase and an inducible Cas9 endonuclease. When used for recombineering and counterselection, this strategy allows minimization of the number of elements necessary to transform in a single electroporation event. The Cas9 delivery platform has been modified to include a range of selectable markers including resistance to apramycin, erythromycin, kanamycin, nourseothricin, spectinomycin or trimethoprim.ResultsOverall electroporation efficiency increased by multiple orders of magnitude (> 100×) using the optimized cell preparation protocol. The CRISPR delivery platform can be stably maintained in a repressed state for multiple generations and induced with anhydrotetracycline. We have introduced targeted mutations in multiple loci using this system with an average turnaround time of 12 days.ConclusionThis improved dual-plasmid CRISPR platform is robust and allows the investigator to rapidly and specifically alter the genomes of staphylococci. These tools will facilitate the study of how specific genetic polymorphisms contribute to various phenotypes in S. aureus, including the virulence of MRSA.Disclosures All Authors: No reported disclosures

Experimental Single-Platform Approach to Enhance the Functionalization of Magnetically Targetable Cells.

Magnetic guidance shows promise as a strategy for improving the delivery and performance of cell therapeutics. However, clinical translation of magnetically guided cell therapy requires cell functionalization protocols that provide adequate magnetic properties in balance with unaltered cell viability and biological function. Existing methodologies for characterizing cells functionalized with magnetic nanoparticles (MNP) produce aggregate results, both distorted and unable to reflect variability in either magnetic or biological properties within a preparation. In the present study, we developed an inverted-plate assay allowing determination of these characteristics using a single-platform approach, and applied this method for a comparative analysis of two loading protocols providing highly uniform vs. uneven MNP distribution across cells. MNP uptake patterns remarkably different between the two protocols were first shown by fluorimetry carried out in a well-scan mode on endothelial cells (EC) loaded with BODIPY558/568-labeled MNP. Using the inverted-plate assay we next demonstrated that, in stark contrast to unevenly loaded cells, more than 50% of uniformly functionalized EC were captured within 5 min over a broad range of MNP doses. Furthermore, magnetically captured cells exhibited unaltered viability, substrate attachment, and proliferation rates. Conducted in parallel, magnetophoretic mobility studies corroborated the markedly superior guidance capacity of uniformly functionalized cells, confirming substantially faster cell capture kinetics on a clinically relevant time scale. Taken together, these results emphasize the importance of optimizing cell preparation protocols with regard to loading uniformity as key to efficient site-specific delivery, engraftment, and expansion of the functionalized cells, essential for both improving performance and facilitating translation of targeted cell therapeutics.

Reporting of Mesenchymal Stem Cell Preparation Protocols and Composition: A Systematic Review of the Clinical Orthopaedic Literature

Background: Mesenchymal stem cells (MSCs) are increasingly being used in the treatment of a wide variety of sports-related conditions. Despite this enthusiasm, the biological properties of MSCs and their effects on musculoskeletal tissue healing remain poorly understood. MSC-based strategies encompass cell populations with heterogeneous phenotypes isolated from multiple tissues and using different methods. Therefore, comprehensive reporting of the source, preparation methods, and characteristics of MSC strategies is essential to enable interpretation of results. Purpose: To perform a systematic review of levels of reporting of key variables in MSC preparation and composition for clinical studies evaluating MSC-based therapies in the treatment of musculoskeletal conditions. Study Design: Systematic review. Methods: A systematic review of the clinical orthopaedic and sports medicine literature from 2002 to 2017 was performed. The following inclusion criteria were used: human clinical trials, published in the English language, involving the administration of MSC-based therapies for orthopaedic or sports medicine applications. In vitro or ex vivo studies, editorials, letters to the editor, and studies relating to cosmetic, neurological, or dental applications were excluded. Results: Of the 1259 studies identified on the initial search, 36 studies were found to satisfy the inclusion criteria for analysis on comprehensive review. Fifty-seven percent of studies evaluated bone marrow–derived MSCs, 41% evaluated adipose-derived MSCs, and 2% evaluated synovium-derived MSCs. Considerable deficiencies in the reporting of key variables, including the details of stem cell processing, culture conditions, and the characteristics of cell populations delivered, were noted. Overall, studies reported only 52% (range, 30%-80%) of variables that may critically influence outcome. No study provided adequate information relating to all of these variables. Conclusion: All existing clinical studies evaluating MSCs for orthopaedic or sports medicine applications are limited by inadequate reporting of both preparation protocols and composition. Deficient reporting of the variables that may critically influence outcome precludes interpretation, prevents others from reproducing experimental conditions, and makes comparisons across studies difficult. We encourage the adoption of emerging minimum reporting standards for clinical studies evaluating the use of MSCs in orthopaedics.

Effects of Perovskite Monovalent Cation Composition on the High and Low Frequency Impedance Response of Efficient Solar Cells

The partial replacement of methylammonium by formamidinium and cesium in organolead trihalide materials is of great importance to improve the performance and stability of photovoltaic solar cells. However, the effect of multiple cations on the cell functioning and their electrical characteristics remains to be clarified. By using the impedance spectroscopy technique, we have investigated the electrical response to a small ac perturbation applied to solar cells implementing hybrid perovskites with various compositions, polarized over a large potential range. The solar cell preparation protocols have been optimized to reach power conversion efficiencies higher than 17%. The impedance response has been investigated both under light and in the dark to discriminate the light sensitive parameters. The spectra have been carefully analyzed using an ad hoc equivalent circuit, and the data have been discussed in the light of the existing literature. The spectra showed no intermediate frequency inductive loop due to...

Efficacy of anti-CD19 chimeric antigen receptor modified T(CAR-T) cell therapy in Chinese patients with relapsed/refractory acute lymphocytic leukemia in a multicenter trial.

7028 Background: r/r B-ALL was reported as the most-threatening disease because of the low disease free survival even treatment with allogeneic hematopoietic stem cell transplantation. For overcoming conventional therapies limitation, autologous CD19CAR-T was performed in our clinical trials to induce remission in patients with r/r disease. 30 patients (from 7 clinical centers, in China) as volunteers with r/r B-ALL were treated by autologous CD19 CAR-T. Methods: 5 juveniles and 25 adults with r/r ALL received autologous CD19 targeted CAR-T, the doses between 1.03 × 106 CAR-T cells/kg and 10.09 × 106CAR-T cells/kg. These 30 cases(from 7 clinical centers, in China) were treated with CAR-T cells from May. 8 2015 to January. 4 2017 (Table1). Patients were monitored for a response. Highly standardized CAR T cell preparation protocol and manageable CRS in most were kept for no significant difference in 7 clinical centers. Results: After treated with CAR-T, a total of 30 cases (5 juveniles and 25 adults coming from 7 clinical centers, in China) with r/r B-ALL were all detected the CAR-T cells proliferated in the blood and bone marrow. The results showed that complete remission (CR) is 26/30(86.67% ) between day7-14 after CD19 CART cell infusion, and 25/30(83.33%) cases arrived at MRD negative. There is about 1/3 of the total cases receiving a repeat infusions following initial ones since these patients have no safety concerns. Additionaly, the severe Cytokine release syndrome (CRS) was 8/30(26.67%) of cases and 24/30(80%) of cases was seen CRS. The anti-IL6R agent tocilizumab and Methylprednisolone were effective confrontation Severe CRS. Conclusions: This is the first multicentre report to our knowledge of successful treatment of r/r ALL with anti-CD19 CAR T cells in China. Even r/r B-ALL with high-burden leukemia patients also was effective and associated with a high remission rate after infused autologous CD19 CAR-T).(NCT 02813837).

CD19 targeted chimeric antigen receptor T (CAR-T) cell immunotherapy has demonstrated significant anti-leukemia activity in pediatric patients with relapsed/refractory acute lymphocytic leukemia: A multicentre study in China.

e18512 Background: Patients with relapsed/refractory B-ALL are difficult to be treated. Autologous CD19 CAR-T may overcome many limitations of conventional therapies and induce remission in patients with relapsed/refractory disease. We explored treatment of 11 pediatric cases (come from Multicenter) with r/r B-ALL and assessed the clinical safety and efficacy. Methods: We infused autologous CD19 CAR-T in patients at doses of 0.45 × 106 to 10.51 × 106cells per kilogram of body weight. Between Oct. 23 2015 and Jan. 12 2017, a total of 11 children from 3 clinical centers (in China) cases were treated with CAR-T cells (Table1). Patients were monitored for a response, toxic effects, and remission rate. Statistical analysis involving categorical or continuous covariates, univariates, or multivariates analyses. Results: 73% (8/11) of the patients achieved complete remission (CR) and MRD negative between Day7-14 after CD19 CART cell infusion. 4 patients received a repeat infusions following initial ones since they have endured the Cytokine release syndrome (CRS) and have no safety concerns. Cytokine release syndrome (CRS) was seen in 73% (8/11) of patients and severe CRS occurred in 18% (2/11) of patients. Severe CRS was relieved gradually when the anti-IL6R agent tocilizumab and Methylprednisolone were administrated. 1 patients performed bone marrow transplant after they achieved MRD negative. The median CR maintenance is 121 day. Conclusions: This effort provides the first large set of pediatrics data that describes the potential for CART19 therapy to benefit Chinese population. Autologous CD19 CAR-T was effective in treating relapsed/refractory B-ALL not only low leukemia burden, but also high-burden leukemia patients. The method also can associated with a high remission rate. Importantly, While the multicenter trial involves 3 clinical centers in China, the variable clinical settings do not seem to impact patient outcomes due to the highly standardized CAR T cell preparation protocol and manageable CRS in most. (NCT 02813837) Clinical trial information: NCT 02813837.

Safety and Efficacy Evaluation of 4SCAR19 Chimeric Antigen Receptor-Modified T Cells Targeting B Cell Acute Lymphoblastic Leukemia - Three-Year Follow-up of a Multicenter Phase I/II Study

Background: CD19 chimeric antigen receptor (CAR)-modified T cell therapy has demonstrated clinical efficacy but often associated with severe adverse effects manifested by cytokine release syndrome (CRS). To increase safety and efficacy of CAR T therapy, a 4thgeneration CAR design has been developed and investigated in a multi-center trial in China.Patients and Methods: From July 2013 to July 2016, the 4SCAR19 phase I/II multi-center trial has enrolled 125 patients (pts) with chemo-resistant, CD19-positive, acute B cell lymphoblastic leukemia (B-ALL) eligible for CAR T cell preparation and infusion. Laboratory data and clinical records were carefully evaluated and 102 pts were qualified for statistical evaluation, including 55 children and 47 adults; 27 had received allo-HSCT prior to CAR T therapy. The median age is 9 (2 to 17) and 37 (19 to 70) for pediatric and adult pts, respectively. The median leukemia blast count in the bone marrow (BM) is 14.5%, with BM blast >50% accounting for nearly one third (33 pts). Autologous/donor T cells were apheresis collected and transduced with an apoptosis-inducible, safety-engineered lentivector CAR containing four intracellular signaling domains: CD19-scFv//CD28/CD137/CD27/CD3ζ-iCasp9 (4SCAR19). Pts received conditioning regimens of cyclophosphamide (17), cyclophosphamide/fludarabine (54), other chemotherapy (29) or none (2), followed by CAR-T cell infusion (average 1.05x106cells/kg). The quality of apheresis cells, gene transfer and T cell proliferation efficiencies, and effective CAR T infusion dose were quantitatively monitored. Statistical analysis used COX proportional hazard model involving categorical or continuous covariates, univariates, or multivariates analyses, and survival analysis was based on right-censored data and Kaplan-Meier estimation (KM curve).Results: The compiled data indicate that the quality of CAR T cells positively correlated with overall survival (OS). The median follow-up time was 7 months (range from 1~35 months). Patient (Pt) cohort 1 (<50% BM blast count, 69 pts) and cohort 2 (≥50% BM blast count, 33 pts) achieved complete response (CR) at 91.3% and 75.8%, respectively. The median OS time of cohort 1 and cohort 2 are 485 days (CI: [387, NA] days) and 317 days (CI: [135, NA]), respectively (P=0.03). The average 4SCAR19 lentivector transduction efficiency was 37.3%. While the infusion dose of CAR T cells positively correlated with OS in pediatric pts (p=0.041), it lacked significant correlation in adults (p=0.95), suggesting that other factors rather than CAR T infusion dose play an important role in CAR T therapy in adults. When pts were analyzed based on low (< 5%) versus high (> 5%) BM blasts, the CRS grade showed no significant correlation with disease burden (P = 0.45 for low burden group, and P = 0.06 for high burden group). Of note that total 73 of the 102 pts experienced 0-1 grade CRS and 8 of them had very high BM leukemia load (>80%), suggesting a very low toxicity of the 4SCAR19 T cells. In addition, of the 17 high (> 80%) BM blast pts, only 3 experienced grade 3-4 CRS. For 38 pts with BM blast ≥ 50%, most had grade 1 (30) or grade 2 (13) CRS, and only 5 pts had grade 3, and 3 pts had grade 4 CRS. For low burden pts (0-5% BM blasts), 86% (42 pts) developed low grade CRS (0 or 1), and even pts with BM blasts above 5%, 53% experienced low grade CRS (0 or 1). Further analysis of inflammatory genetic profile reveals that high CRS might correlate with high inflammatory profile, as several pts with high inflammatory gene patterns, while only had residual disease or no detectable leukemia cells (BM blasts 0-0.005%), developed grade 3-4 CRS.Conclusion: The three-year follow-up of the 4SCAR19 T cell therapy further supports that CAR T immunotherapy could benefit not only low leukemia burden pts, but also late-stage, chemo-resistant, very high-burden leukemia pts. Importantly, our study demonstrates a good safety profile of the 4SCAR19 T cells even under high disease burden. While the multicenter trial involves 22 clinical centers, the variable clinical settings do not seem to impact patient outcomes due to the highly standardized CAR T cell preparation protocol and manageable CRS in most. DisclosuresNo relevant conflicts of interest to declare.

A Cell Graft or a Drug? Legal and Practical Aspects of Somatic Cells Application in Graft-Versus-Host Disease Experimental Treatment: The Polish Experience.

Allogeneic hematopoietic stem and progenitor cell (HSPC) transplantation and organ transplantation are well-established treatments for different conditions. Graft versus host disease (GvHD) is a major complication in both methods. There has been a rapid increase in the application of nonhematopoietic somatic cells, such as mesenchymal stem cells and regulatory T cells in GvHD experimental therapy. According to current European Union (EU) law, human cells intended for human application can be considered either as cell grafts or as advanced therapy medicinal products (ATMPs). The aim of the paper is an attempt to answer, based on GvHD experimental treatment data as well as existing EU and Polish law, whether cells cease to be cells (cell grafts) and becomes drugs (ATMPs); if yes, when; and what are the consequences of such situation both for patients as well as for physicians engaged in the treatment process in Poland. Data analysis confirmed the interest in the experimental GvHD cell therapy. In the vast majority of analyzed cases the invitro culture step in the cell preparation protocols has been foreseen. Therefore, the answer to title question was unambiguous-expanded cells are recognized in EU as ATMPs. In borderline cases, a scientific recommendation by the Committee for Advanced Therapies (CAT) of the European Medicines Agency (EMA) can play an important auxiliary role; however, it is currently neither required by Polish law nor legally binding in Poland.

Automated Electrophysiological and Pharmacological Evaluation of Human Pluripotent Stem Cell-Derived Cardiomyocytes.

Automated planar patch clamp systems are widely used in drug evaluation studies because of their ability to provide accurate, reliable, and reproducible data in a high-throughput manner. Typically, CHO and HEK tumorigenic cell lines overexpressing single ion channels are used since they can be harvested as high-density, homogenous, single-cell suspensions. While human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) are physiologically more relevant, these cells are fragile, have complex culture requirements, are inherently heterogeneous, and are expensive to produce, which has restricted their use on automated patch clamp (APC) devices. Here, we used high efficiency differentiation protocols to produce cardiomyocytes from six different hPSC lines for analysis on the Patchliner (Nanion Technologies GmbH) APC platform. We developed a two-step cell preparation protocol that yielded cell catch rates and whole-cell breakthroughs of ∼80%, with ∼40% of these cells allowing electrical activity to be recorded. The protocol permitted formation of long-lasting (>15 min), high quality seals (>2 GΩ) in both voltage- and current-clamp modes. This enabled density of sodium, calcium, and potassium currents to be evaluated, along with dose–response curves to their respective channel inhibitors, tetrodotoxin, nifedipine, and E-4031. Thus, we show the feasibility of using the Patchliner platform for automated evaluation of the electrophysiology and pharmacology of hPSC-CMs, which will enable considerable increase in throughput for reliable and efficient drug evaluation.

Enhanced 3-methylcatechol production by Pseudomonas putida TODE1 in a two-phase biotransformation system.

In this study, genetically engineered Pseudomonas putida TODE1 served as a biocatalyst for the bioproduction of valuable 3-methylcatechol (3MC) from toluene in an aqueous-organic two-phase system. The two-phase system was used as an approach to increase the biocatalyst efficiency. Among the organic solvent tested, n-decanol offered several benefits including having the highest partitioning of 3MC, with a high 3MC yield and low cell toxicity. The effect of media supplementation with carbon/energy sources (glucose, glycerol, acetate and succinate), divalent metal cations (Mg(2+), Ca(2+), Mn(2+) and Fe(2+)), and short-chain alcohols (ethanol, n-propanol and n-butanol) as a cofactor regeneration system on the toluene dioxygenase (TDO) activity, cell viability, and overall 3MC yield were evaluated. Along with the two-step cell preparation protocol, supplementation of the medium with 4 mM glycerol as a carbon/energy source, and 0.4 mM Fe(2+) as a cofactor for TDO significantly enhanced the 3MC production level. When in combination with the use of n-decanol and n-butanol as the organic phase, a maximum overall 3MC concentration of 31.8 mM (166 mM in the organic phase) was obtained in a small-scale production, while it was at 160.5 mM (333.2 mM in the organic phase) in a 2-L scale. To our knowledge, this is the highest 3MC yield obtained from a TDO-based system so far.

Mesenchymal Stem Cells for Regenerative Therapy: Optimization of Cell Preparation Protocols

Administration of bone marrow-derived mesenchymal stem cells (MSCs) is an innovative approach for the treatment of a range of diseases that are not curable by current therapies including heart failure. A number of clinical trials have been completed and many others are ongoing; more than 2,000 patients worldwide have been administered with culture-expanded allogeneic or autologous MSCs for the treatment of various diseases, showing feasibility and safety (and some efficacy) of this approach. However, protocols for isolation and expansion of donor MSCs vary widely between these trials, which could affect the efficacy of the therapy. It is therefore important to develop international standards of MSC production, which should be evidence-based, regulatory authority-compliant, of good medical practice grade, cost-effective, and clinically practical, so that this innovative approach becomes an established widely adopted treatment. This review article summarizes protocols to isolate and expand bone marrow-derived MSCs in 47 recent clinical trials of MSC-based therapy, which were published after 2007 onwards and provided sufficient methodological information. Identified issues and possible solutions associated with the MSC production methods, including materials and protocols for isolation and expansion, are discussed with reference to relevant experimental evidence with aim of future clinical success of MSC-based therapy.

Optimization of a Cav1.2 Cell Line for Use on QPatch and PatchXpress

Ion channel currents comprise the cardiac action potential and are important in cardiac safety liability assessment of potential drug candidates. The gold standard for assessing ion channel activity is the voltage clamp technique, but this technique is a very low throughput process. Planar patch technology (QPatch and PatchXpress) allows for moderate throughput by providing automated, simultaneous whole cell voltage clamp recordings from cells heterologously expressing the channel of interest. Ion channels routinely screened for cardiovascular safety are hERG (Kv11.1), Nav1.5, Kir2.1 and KvLQT/minK using either PatchXpress or QPatch instruments. In this study, we highlight the validation of Cav1.2 (L-type calcium channel) on our automated electrophysiology systems for cardiovascular safety screening. The L-type calcium channel is expressed in the cardiovascular system both in smooth and cardiac muscle. Potent L-type calcium channel antagonists can lower blood pressure, reduce cardiac contractility, and potentially increase the P-R interval on the electrocardiogram (ECG). Cav1.2 was expressed in CHO cells using a tetracycline inducible vector. Because of this we needed to optimize expression level by varying the induction variables. Addition of an L-type antagonist (verapamil) also provided benefit by keeping well-expressing cells viable after induction. In order to optimize flexibility in performing experiments, we also prepared the cells as a cryo-preserved subtrate. Cav1.2 channel kinetics for both activation and inactivation were investigated, and potencies of 8 reference compounds (weak and strong antagonists) were assessed on both platforms. In conclusion, we have optimized tissue culture conditions, cell preparation and voltage clamp protocols on two automated electrophysiology platforms to provide cardiac safety evaluation of drug candidates using an inducible Cav1.2 cell line.

Validated protocol for FoxP3 reveals increased expression in type 1 diabetes patients

FoxP3 has become a key identifier of regulatory T cells. Investigators have used a variety of antibodies and methods for detecting FoxP3 by flow cytometry. To standardize FoxP3 antibody staining for use in clinical trial samples, we tested various antibodies from different vendors, cell preparation protocols and fix/perm reagents, and cell isolation procedures. Using this optimized staining protocol, we evaluated clinical specimens from patients with multiple sclerosis (MS) or type 1 diabetes. FoxP3 antibodies from eBioscience (236A/E7 and PCH101) and BioLegend (206D) were evaluated along with their respective methods and fix/perm reagents for preparation and staining of FoxP3 for flow cytometry. Fresh washed blood and frozen or fresh PBMC were evaluated. Upon optimization of the protocol, clinical samples (frozen PBMC) from patients with MS or type 1 diabetes and healthy control donors were evaluated with the BioLegend antibody. Clone 206D from BioLegend yielded optimal staining and the fix/perm reagents from both eBioscience and BioLegend were comparable. Data were also comparable between cells separated by Ficoll (fresh or frozen) and washed blood samples, allowing this protocol to be applicable to different types of samples. We validated this protocol using clinical samples and saw a significant increase in FoxP3 expression in the patients with type 1 diabetes but not in the MS. The results from this study will allow the assessment of FoxP3 by flow cytometry on samples from clinical sites that are analyzed in real time on fresh blood or frozen PBMC.