Preservation of stem cells

Engineering a Microfluidic Platform to Cryopreserve Stem Cells: A DMSO-Free Sustainable Approach

Human adipose-derived stem cells (hASCs) are cryopreserved traditionally using dimethyl sulfoxide (DMSO) as the cryoprotectant agent. DMSO penetrates cell membranes and prevents cellular damage during cryopreservation. However, DMSO is not inert to cells, inducing cytotoxic effects by causing mitochondrial dysfunction, reduced cell proliferation, and impaired hASCs transplantation. Additionally, large-scale production of DMSO and contamination can adversely impact the environment. A sustainable, green alternative to DMSO is trehalose, a natural disaccharide cryoprotectant agent that does not pose any risk of cytotoxicity. However, the cellular permeability of trehalose is less compared to DMSO. Here, a microfluidic chip is developed for the intracellular delivery of trehalose in hASCs. The chip is designed for mechanoporation, which creates transient pores in cell membranes by mechanical deformation. Mechanoporation allows the sparingly permeable trehalose to be internalized within the cell cytosol. The amount of trehalose delivered intracellularly is quantified and optimized based on cellular compatibility and functionality. Furthermore, whole-transcriptome sequencing confirms that less than 1% of all target genes display at least a twofold change in expression when cells are passed through the chip compared to untreated cells. Overall, the results confirm the feasibility and effectiveness of using this microfluidic chip for DMSO-free cryopreservation of hASCs.

Ascorbic acid enhances the cold preservation period of human adipose tissue-derived mesenchymal stromal cells

Introduction

We previously developed 3% trehalose-added lactated Ringer's solution (LR-3T) and 3% trehalose- and 5% dextran-40-added lactated Ringer's solution (LR-3T-5D), which can be used to preserve adipose-derived mesenchymal stem cells (hADSCs) for 24 h at 5 and 25 °C. However, it is necessary to further extend the storage duration of cells to expand transportation zones and ensure time for quality control testing of final cell products. Therefore, we attempted to prolong the preservation duration of hADSCs by adding supplements to LR-3T-5D. We focused on ascorbic acid as an antioxidant because it is widely clinically as a nutrient.

Methods

We added the antioxidant ascorbic acid to LR-3T-5D and evaluated the viability, colony formation rate, proliferative capacity, and surface markers of hADSCs before and after preservation at 5 °C.

Results

Analysis of the concentration of ascorbic acid added to LR-3T-5D indicated that 1000 mg/L was the optimal concentration for maintaining the viability of hADSCs after 72 h of cold preservation. No changes were observed in the expression of specific cell surface markers or in the potential of hADSCs to differentiate into adipocytes, osteoblasts, or chondrocytes before and after cold preservation.

Discussion

These results suggest that cold preservation of hADSCs in LR-3T-5D supplemented with ascorbic acid helps maintain the quality of cells for use in cell therapy.

Toward a Transportable Cell Culture Platform for Evaluating Radiotherapy Dose Modifying Factors

The current tools for validating dose delivery and optimizing new radiotherapy technologies in radiation therapy do not account for important dose modifying factors (DMFs), such as variations in cellular repair capability, tumor oxygenation, ultra-high dose rates and the type of ionizing radiation used. These factors play a crucial role in tumor control and normal tissue complications. To address this need, we explored the feasibility of developing a transportable cell culture platform (TCCP) to assess the relative biological effectiveness (RBE) of ionizing radiation. We measured cell recovery, clonogenic viability and metabolic viability of MDA-MB-231 cells over several days at room temperature in a range of concentrations of fetal bovine serum (FBS) in medium-supplemented gelatin, under both normoxic and hypoxic oxygen environments. Additionally, we measured the clonogenic viability of the cells to characterize how the duration of the TCCP at room temperature affected their radiosensitivity at doses up to 16 Gy. We found that (78±2)% of MDA-MB-231 cells were successfully recovered after being kept at room temperature for three days in 50% FBS in medium-supplemented gelatin at hypoxia (0.4±0.1)% pO2, while metabolic and clonogenic viabilities as measured by ATP luminescence and colony formation were found to be (58±5)% and (57±4)%, respectively. Additionally, irradiating a TCCP under normoxic and hypoxic conditions yielded a clonogenic oxygen enhancement ratio (OER) of 1.4±0.6 and a metabolic OER of 1.9±0.4. Our results demonstrate that the TCCP can be used to assess the RBE of a DMF and provides a feasible platform for assessing DMFs in radiation therapy applications.

Where Are We and Where to Next?-The Future of Perianal Crohn's Disease Management

Perianal fistulizing Crohn's Disease (pCD) affects about 25% of patients with Crohn's Disease (CD). It remains a difficult entity to manage with a therapeutic ceiling of treatment success despite improving medical and surgical management. The refractory nature of the disease calls for an imminent need to better understand its immunopathogenesis and classification to better streamline our treatment options. In this article, we overview the current state of pCD management and discuss where the future of its management may lie.

Cryopreservation: A Comprehensive Overview, Challenges, and Future Perspectives

Cryopreservation is the most prevalent method of long-term cell preservation. Effective cell cryopreservation depends on freezing, adequate storage, and correct thawing techniques. Recent advances in cryopreservation techniques minimize the cellular damage which occurs while processing samples. This article focuses on the fundamentals of cryopreservation techniques and how they can be implemented in a variety of clinical settings. The article presents a brief description of each of the standard cryopreservation procedures, such as slow freezing and vitrification. Alongside that, the membrane permeating and nonpermeating cryoprotectants are briefly discussed, along with current advancements in the field of cryopreservation and variables influencing the cryopreservation process. The diminution of cryoinjury incurred by the cell via the resuscitation process will also be highlighted. In the end application of cryopreservation techniques in many fields, with a special emphasis on stem cell preservation techniques and current advancements presented. Furthermore, the challenges while implementing cryopreservation and the futuristic scope of the fields are illustrated herein. The content of this review sheds light on various ways to enhance the output of the cell preservation process and minimize cryoinjury while improving cell revival.

Novel systems to study vector-pathogen interactions in malaria

Some parasitic diseases, such as malaria, require two hosts to complete their lifecycle: a human and an insect vector. Although most malaria research has focused on parasite development in the human host, the life cycle within the vector is critical for the propagation of the disease. The mosquito stage of the Plasmodium lifecycle represents a major demographic bottleneck, crucial for transmission blocking strategies. Furthermore, it is in the vector, where sexual recombination occurs generating "de novo" genetic diversity, which can favor the spread of drug resistance and hinder effective vaccine development. However, understanding of vector-parasite interactions is hampered by the lack of experimental systems that mimic the natural environment while allowing to control and standardize the complexity of the interactions. The breakthrough in stem cell technologies has provided new insights into human-pathogen interactions, but these advances have not been translated into insect models. Here, we review in vivo and in vitro systems that have been used so far to study malaria in the mosquito. We also highlight the relevance of single-cell technologies to progress understanding of these interactions with higher resolution and depth. Finally, we emphasize the necessity to develop robust and accessible ex vivo systems (tissues and organs) to enable investigation of the molecular mechanisms of parasite-vector interactions providing new targets for malaria control.

Optimizing the viability, stability, and potency of Buffy coat isolated T cells for homologous dendritic cell co-cultures: A method for handling and preservation

The utilization of T cells is becoming increasingly prominent in both clinical and research domains. However, the need to optimize preservation methodologies for extended periods of time remains unmet. To address this issue, we have developed a protocol for the handling and preservation of T cells that facilitates successful donor homologous co-cultures with dendritic cells (DCs), and preserves the cells for subsequent testing. Our method enhances experimental efficiency by reducing time and effort, and simplifying the use of T cells in mono or co-cultures. Our T cell handling and preservation methodology demonstrates the stability and viability of these cells in co-cultures, with viability exceeding 93% before and after liquid nitrogen preservation. Additionally, the preserved cells display no unspecific activation, as evidenced by the unaltered expression of the T cell activation marker CD25. The proliferation profile of preserved T cells used in DC-T cell co-cultures, stimulated by lipopolysaccharide (LPS)-activated DCs, attests to the potency and ability of these cells to interact and proliferate. These findings underscore the efficacy of our handling and preservation methodology in maintaining T cell viability and stability. Preserving donor T cells not only reduces the inconvenience of repeated blood donations but also enhances accessibility to a particular population of T cells for experimental or clinical applications, such as chimeric antigen receptor T cells.

Industrial Biotechnology Conservation Processes: Similarities with Natural Long-Term Preservation of Biological Organisms

Cryopreservation and lyophilization processes are widely used for conservation purposes in the pharmaceutical, biotechnological, and food industries or in medical transplantation. Such processes deal with extremely low temperatures (e.g., -196 °C) and multiple physical states of water, a universal and essential molecule for many biological lifeforms. This study firstly considers the controlled laboratory/industrial artificial conditions used to favor specific water phase transitions during cellular material cryopreservation and lyophilization under the Swiss progenitor cell transplantation program. Both biotechnological tools are successfully used for the long-term storage of biological samples and products, with reversible quasi-arrest of metabolic activities (e.g., cryogenic storage in liquid nitrogen). Secondly, similarities are outlined between such artificial localized environment modifications and some natural ecological niches known to favor metabolic rate modifications (e.g., cryptobiosis) in biological organisms. Specifically, examples of survival to extreme physical parameters by small multi-cellular animals (e.g., tardigrades) are discussed, opening further considerations about the possibility to reversibly slow or temporarily arrest the metabolic activity rates of defined complex organisms in controlled conditions. Key examples of biological organism adaptation capabilities to extreme environmental parameters finally enabled a discussion about the emergence of early primordial biological lifeforms, from natural biotechnology and evolutionary points of view. Overall, the provided examples/similarities confirm the interest in further transposing natural processes and phenomena to controlled laboratory settings with the ultimate goal of gaining better control and modulation capacities over the metabolic activities of complex biological organisms.

Recent Developments in Cell Shipping Methods

As opposed to remarkable advances in the cell therapy industry, researches reveal inexplicable difficulties associated with preserving and post-thawing cell death. Post cryopreservation apoptosis is a common occurrence that has attracted the attention of scientists to use apoptosis inhibitors. Transporting cells without compromising their survival and function is crucial for any experimental cell-based therapy. Preservation of cells allows the safe transportation of cells between distances and improves quality control testing in clinical and research applications. The vitality of transported cells is used to evaluate the efficacy of transportation strategies. For many decades, the conventional global methods of cell transfer were not only expensive but also challenging and had adverse effects. The first determination of some projects is optimizing cell survival after cryopreservation. The new generation of cryopreservation science wishes to find appropriate and alternative methods for cell transportation to ship viable cells at an ambient temperature without dry ice or in media-filled flasks. The diversity of cell therapies demands new cell shipping methodologies and cryoprotectants. In this review, we tried to summarize novel improved cryopreservation methods and alternatives to cryopreservation with safe and viable cell shipping at ambient temperature, including dry preservation, hypothermic preservation, gel-based methods, encapsulation methods, fibrin microbeads, and osmolyte solution compositions. This article is protected by copyright. All rights reserved.

Clinically relevant preservation conditions for mesenchymal stem/stromal cells derived from perinatal and adult tissue sources

The interplay between mesenchymal stem/stromal cells (MSCs) and preservation conditions is critical to maintain the viability and functionality of these cells before administration. We observed that Ringer lactate (RL) maintained high viability of bone marrow–derived MSCs for up to 72 h at room temperature (18°C–22°C), whereas adipose‐derived and umbilical cord‐derived MSCs showed the highest viability for 72 h at a cold temperature (4°C–8°C). These cells maintained their adherence ability with an improved recovery rate and metabolic profiles (glycolysis and mitochondrial respiration) similar to those of freshly harvested cells. Growth factor and cytokine analyses revealed that the preserved cells released substantial amounts of leukaemia inhibitory factors (LIFs), hepatocyte growth factor (HGF) and vascular endothelial growth factor‐A (VEGF‐A), as well as multiple cytokines (eg IL‐4, IL‐6, IL‐8, MPC‐1 and TNF‐α). Our data provide the simplest clinically relevant preservation conditions that maintain the viability, stemness and functionality of MSCs from perinatal and adult tissue sources.

Optimized Manufacture of Lyophilized Dermal Fibroblasts for Next-Generation Off-the-Shelf Progenitor Biological Bandages in Topical Post-Burn Regenerative Medicine

Cultured fibroblast progenitor cells (FPC) have been studied in Swiss translational regenerative medicine for over two decades, wherein clinical experience was gathered for safely managing burns and refractory cutaneous ulcers. Inherent FPC advantages include high robustness, optimal adaptability to industrial manufacture, and potential for effective repair stimulation of wounded tissues. Major technical bottlenecks in cell therapy development comprise sustainability, stability, and logistics of biological material sources. Herein, we report stringently optimized and up-scaled processing (i.e., cell biobanking and stabilization by lyophilization) of dermal FPCs, with the objective of addressing potential cell source sustainability and stability issues with regard to active substance manufacturing in cutaneous regenerative medicine. Firstly, multi-tiered FPC banking was optimized in terms of overall quality and efficiency by benchmarking key reagents (e.g., medium supplement source, dissociation reagent), consumables (e.g., culture vessels), and technical specifications. Therein, fetal bovine serum batch identity and culture vessel surface were confirmed, among other parameters, to largely impact harvest cell yields. Secondly, FPC stabilization by lyophilization was undertaken and shown to maintain critical functions for devitalized cells in vitro, potentially enabling high logistical gains. Overall, this study provides the technical basis for the elaboration of next-generation off-the-shelf topical regenerative medicine therapeutic products for wound healing and post-burn care.

Dental pulp stem cells response on the nanotopography of scaffold to regenerate dentin-pulp complex tissue

The study of regenerative dentistry receives a fast growing interest. The potential ability of the dentin-pulp complex to regenerate is both promising and perplexing. To answer the challenging nature of the dental environment, scientists have developed various combinations of biomaterial scaffolds, stem cells, and incorporation of several growth factors. One of the crucial elements of this tissue engineering plan is the selection and fabrication of scaffolds. However, further findings suggest that cell behavior hugely depends on mechanical signaling. Nanotopography modifies scaffolds to alter cell migration and differentiation. However, to the best of the author's knowledge, there are very few studies addressing the correlation between nanotopography and dentin-pulp complex regeneration. Therefore, this article presents a comprehensive review of these studies and suggests a direction for future developments, particularly in the incorporation of nanotopography design for dentin-pulp complex regeneration.

Differential Evolution for the Optimization of DMSO-Free Cryoprotectants: Influence of Control Parameters

This study presents the influence of control parameters including population (NP) size, mutation factor (F), crossover (Cr), and four types of differential evolution (DE) algorithms including random, best, local-to-best, and local-to-best with self-adaptive (SA) modification for the purpose of optimizing the compositions of dimethylsufloxide (DMSO)-free cryoprotectants. Post-thaw recovery of Jurkat cells cryopreserved with two DMSO-free cryoprotectants at a cooling rate of 1 °C/min displayed a nonlinear, four-dimensional structure with multiple saddle nodes, which was a suitable training model to tune the control parameters and select the most appropriate type of differential evolution algorithm. Self-adaptive modification presented better performance in terms of optimization accuracy and sensitivity of mutation factor and crossover among the four different types of algorithms tested. Specifically, the classical type of differential evolution algorithm exhibited a wide acceptance to mutation factor and crossover. The optimization performance is more sensitive to mutation than crossover and the optimization accuracy is proportional to the population size. Increasing population size also reduces the sensitivity of the algorithm to the value of the mutation factor and crossover. The analysis of optimization accuracy and convergence speed suggests larger population size with F > 0.7 and Cr > 0.3 are well suited for use with cryopreservation optimization purposes. The tuned differential evolution algorithm is validated through finding global maximums of other two DMSO-free cryoprotectant formulation datasets. The results of these studies can be used to help more efficiently determine the optimal composition of multicomponent DMSO-free cryoprotectants in the future.

Assessment of Post-thaw Quality of Dental Mesenchymal Stromal Cells After Long-Term Cryopreservation by Uncontrolled Freezing

Cryopreservation abilities of dental tissue-derived mesenchymal stromal cells (DMSCs) including dental pulp stem cells (DPSCs) and dental follicle stem cells (DFSC) play an important role in the applications of these cells in clinical settings. In this context, we checked whether storage at - 80 °C in 10% DMSO for a longer period has any adverse effect on the functionality and genetic stability. We carried our studies on DPSC and DFSC samples that were revived after a maximum of 5 years of cryopreservation. We observed that even after long-term uncontrolled freezing at - 80 °C, these cells survived and proliferated efficiently. The assessment was made based on their post-thaw morphology, immunophenotypes, differentiation potential, growth kinetics, and genetic features. These cells retained the expression of stemness markers, differentiation ability and maintained their normal karyotype. Our results indicated no significant morphological or immunophenotypic differences between the cryopreserved DMSCs and the fresh DMSCs. Our study implies that mesenchymal stromal cells derived from the dental tissue origin are very robust and do not require any sophisticated preservation protocols. Thus, these can be an ideal source for research, stem cell banking, as well as successful clinical applications in tissue engineering and cell-based therapeutics. Graphical Abstract Schematic diagram showing the cryopreservation of DMSCs by uncontrolled freezing at -80 c has no adverse effects on their functionality and genetic stability.

The role of preservation in the variability of regenerative medicine products

Regenerative medicine (RM) has the potential to restore or establish normal function of cells, tissues and organs that have been lost due to age, disease or injury. It is common for the site of raw material collection, site of manufacture and site of clinical use to be different for RM products, and at the same time cells must remain viable and functional during transportation among different sites. Freezing products down to cryogenic temperatures along with cold chain transportation has become an effective method of preserving RM products. The quality of RM products along this supply chain represents the cumulative effects of all of the processing steps and all of the reagents used in the process. A variety of sources of variability in the preservation of RM products can result in both cell losses and greater variability in the quality of RM products. The purpose of this article is to review the sources of variability in the preservation process as well as the methods by which variability can be controlled or avoided.

Pericardial application as a new route for implanting stem-cell cardiospheres to treat myocardial infarction

KEY POINTS

Cardiospheres (CSps) are a promising new form of cardiac stem cells with advantage over other stem cells for myocardial regeneration, but direct implantation of CSps by conventional routes has been limited due to potential embolism. We have implanted CSps into the pericardial cavity and systematically demonstrated its efficacy regarding myocardial infarction. Stem cell potency and cell viability can be optimized in vitro prior to implantation by pre-conditioning CSps with pericardial fluid and hydrogel packing. Transplantation of optimized CSps into the pericardial cavity improved cardiac function and alleviated myocardial fibrosis, increased myocardial cell survival and promoted angiogenesis. Mechanistically, CSps are able to directly differentiate into cardiomyocytes in vivo and promote regeneration of myocardial cells and blood vessels through a paracrine effect with released growth factors as potential paracrine mediators. These findings establish a new strategy for therapeutic myocardial regeneration to treat myocardial infarction.

ABSTRACT

Cardiospheres (CSps) are a new form of cardiac stem cells with an advantage over other stem cells for myocardial regeneration. However, direct implantation of CSps by conventional routes to treat myocardial infarction has been limited due to potential embolism. We have implanted CSps into the pericardial cavity and systematically assessed its efficacy on myocardial infarction. Preconditioning with pericardial fluid enhanced the activity of CSps and matrix hydrogel prolonged their viability. This shows that pretransplant optimization of stem cell potency and maintenance of cell viability can be achieved with CSps. Transplantation of optimized CSps into the pericardial cavity improved cardiac function and alleviated myocardial fibrosis in the non-infarcted area, and increased myocardial cell survival and promoted angiogenesis in the infarcted area. Mechanistically, CSps were able to directly differentiate into cardiomyocytes in vivo and promoted regeneration of myocardial cells and blood vessels in the infarcted area through a paracrine effect with released growth factors in pericardial cavity serving as possible paracrine mediators. This is the first demonstration of direct pericardial administration of pre-optimized CSps, and its effectiveness on myocardial infarction by functional and morphological outcomes with distinct mechanisms. These findings establish a new strategy for therapeutic myocardial regeneration to treat myocardial infarction.

Use of Tethered Hydrogel Microcoatings for Mesenchymal Stem Cell Equilibrium, Differentiation, and Self-Organization into Microtissues

Therapeutic adult mesenchymal stem cells (MSCs) lose multipotency and multilineage specialization in culture and after transplantation due to the absence of complex biological architecture. Here, it is shown that a transient ultrathin covering of permeable biomaterial can be differentially formulated to either preserve multipotency or induce multidifferentiation. Accordingly, populations of single, spherical MSCs in suspended media with high selectivity and specificity can be coated. Assembly of single, double, and triple hydrogel layers at MSC membranes is initiated by first attaching MSC-specific immunoglobulins onto CD90 or Stro-1 receptors and UEA-1 and soybean lectins. A secondary biotinylated immunoglobulin is targeted for avidin binding, which becomes an attractor for biotinylated alginate or hyaluronate, which are subsequently stiffened and gelled, in situ around the entire cell surface. Alginate microcoatings permeated with mobile BMP-2-induced osteospecialized tissue, vascular endothelial growth factor (VEGF) induced microcapillary formation, while microcoatings, with selected basement membrane proteins, preserve the multipotent phenotype of MSCs, for continuing rounds of culture and directed specialization. Furthermore, forced packing of microcoated MSC populations creates prototypical tissue compartments: the coating partially simulating the extracellular matrix structures. Remarkably, microcoated MSC clusters show a tremendous simulation of a common embryological tissue transformation into the epithelium. Thus, confinement of free morphology exerts another control on tissue specialization and formation.

Synergistic Development of Biochips and Cell Preservation Methodologies: A Tale of Converging Technologies

PURPOSE OF THE REVIEW

Over the past several decades, cryopreservation has been widely used to preserve cells during long term storage, but advances in stem cell therapies, regenerative medicine, and miniaturized cell-based diagnostics and sensors are providing new targets of opportunity for advancing preservation methodologies. The advent of microfluidics-based devices is an interesting case in which the technology has been used to improve preservation processing, but as the devices have evolved to also include cells, tissues, and simulated organs as part of the architecture, the biochip itself is a desirable target for preservation. In this review, we will focus on the synergistic co-development of preservation methods and biochip technologies, while identifying where the challenges and opportunities lie in developing methods to place on-chip biologics on the shelf, ready for use.

RECENT FINDINGS

Emerging studies are demonstrating that the cost of some biochips have been reduced to the extent that they will have high utility in point-of-care settings, especially in low resource environments where diagnostic capabilities are limited. Ice-free low temperature vitrification and anhydrous vitrification technologies will likely emerge as the preferred strategy for long-term preservation of bio-chips.

SUMMARY

The development of preservation methodologies for partially or fully assembled biochips would enable the widespread distribution of these technologies and enhance their application.

Using Stem Cells to Grow Artificial Tissue for Peripheral Nerve Repair

Peripheral nerve injury continues to pose a clinical hurdle despite its frequency and advances in treatment. Unlike the central nervous system, neurons of the peripheral nervous system have a greater ability to regenerate. However, due to a number of confounding factors, this is often both incomplete and inadequate. The lack of supportive Schwann cells or their inability to maintain a regenerative phenotype is a major factor. Advances in nervous system tissue engineering technology have led to efforts to build Schwann cell scaffolds to overcome this and enhance the regenerative capacity of neurons following injury. Stem cells that can differentiate along a neural lineage represent an essential resource and starting material for this process. In this review, we discuss the different stem cell types that are showing promise for nervous system tissue engineering in the context of peripheral nerve injury. We also discuss some of the biological, practical, ethical, and commercial considerations in using these different stem cells for future clinical application.

Pre-Plated Cell Lines for ADMETox Applications in the Pharmaceutical Industry

Membrane transporters significantly modulate membrane permeability of endobiotics and xenobiotics, such as bile acids and drugs, respectively. Various in vitro methods have been established for both ATP-binding cassette (ABC) transporters to examine cellular efflux and uptake, and for solute carriers (SLC) to examine cellular uptake of substrates. Cell-based systems are the models of choice to test drug-transporter interactions as well as drug-drug interactions for research and regulatory purposes, albeit, for low passive permeability substrates of ABC transporters, vesicular uptake assays are also recommended. Commercially available pre-plated cells (e.g., immortalized or transfected) offer a useful alternative to in-house cell culture. Three main methods are known to manufacture pre-plated cultures: regular culture medium with vacuum seal, cryopreserved delivery, and the solid shipping media technology. The regular culture medium and the solid shipping media technologies provide ready-to-use models for end users. Models expressing a broad selection of transporters are available in pre-plated formats for absorption, distribution, metabolism, excretion, and toxicity (ADMETox) studies. Conversely, the application and utility of pre-plated cultures coupled with personal experiences have not been extensively covered in published research papers or reviews, despite availability and significant use of pre-plated products in the pharmaceutical industry. In this overview, we will briefly describe: 1) in vitro tools commonly used for ADMETox testing; 2) methods employed in manufacturing, shipment and preparation of pre-plated cell lines; 3) cell-membrane barrier models currently available in pre-plated format to reproduce passage restriction of physiological barriers to certain compounds; and 4) recommended pre-plated cell lines overexpressing uptake transporters for ADMETox applications.

Preserving human cells for regenerative, reproductive, and transfusion medicine

Cell cryopreservation maintains cellular life at sub-zero temperatures by slowing down biochemical processes. Various cell types are routinely cryopreserved in modern reproductive, regenerative, and transfusion medicine. Current cell cryopreservation methods involve freezing (slow/rapid) or vitrifying cells in the presence of a cryoprotective agent (CPA). Although these methods are clinically utilized, cryo-injury due to ice crystals, osmotic shock, and CPA toxicity cause loss of cell viability and function. Recent approaches using minimum volume vitrification provide alternatives to the conventional cryopreservation methods. Minimum volume vitrification provides ultra-high cooling and rewarming rates that enable preserving cells without ice crystal formation. Herein, we review recent advances in cell cryopreservation technology and provide examples of techniques that are utilized in oocyte, stem cell, and red blood cell cryopreservation.

Transporting Cells in Semi-Solid Gel Condition and at Ambient Temperature

Mammalian cells including human cancer cells are usually transported in cryovials on dry ice or in a liquid nitrogen vapor shipping vessel between different places at long distance. The hazardous nature of dry ice and liquid nitrogen, and the associated high shipping cost strongly limit their routine use. In this study, we tested the viability and properties of cells after being preserved or shipped over long distance in Matrigel mixture for different days. Our results showed that cells mixed with Matrigel at suitable ratios maintained excellent viability (>90%) for one week at room temperature and preserved the properties such as morphology, drug sensitivity and metabolism well, which was comparable to cells cryopreserved in liquid nitrogen. We also sent cells in the Matrigel mixture via FedEx service to different places at ambient temperature. Upon arrival, it was found that over 90% of the cells were viable and grew well after replating. These data collectively suggested that our Matrigel-based method was highly convenient for shipping live cells for long distances in semi-solid gel condition and at ambient temperature.

Emerging medical devices for minimally invasive cell therapy

The past decade has seen the first wave of cell-based therapeutics undergo clinical trials with varying degrees of success. Although attention is increasingly focused on clinical trial design, owing to spiraling regulatory costs, tools used in delivering cells and sustaining the cells' viability and functions in vivo warrant careful scrutiny. While the clinical administration of cell-based therapeutics often requires additional safeguarding and targeted delivery compared with traditional therapeutics, there is significant opportunity for minimally invasive device-assisted cell therapy to provide the physician with new regenerative options at the point of care. Herein we detail exciting recent advances in medical devices that will aid in the safe and efficacious delivery of cell-based therapeutics.

Mesenchymal stem or stromal cells: a review of clinical applications and manufacturing practices

Mesenchymal stem cells (MSCs) have recently generated great interest in the fields of regenerative medicine and immunotherapy due to their unique biologic properties. In this review we attempt to provide an overview of the current clinical status of MSC therapy, primarily focusing on immunomodulatory and regenerative or tissue repair applications of MSCs. In addition, current manufacturing is reviewed with attention to variation in practices (e.g., starting material, approach to culture and product testing). There is considerable variation among the 218 clinical trials assessed here; variations include proposed mechanisms of action, optimal dosing strategy, and route of administration. To ensure the greatest likelihood of success in clinical trials as the field progresses, attention must be given to the optimization of MSC culture.

Effective surface-based cryopreservation of human embryonic stem cells by vitrification

Human embryonic stem cells (hESCs) are candidates for many applications in the areas of regenerative medicine, tissue engineering, basic scientific research as well as pharmacology and toxicology. However, use of hESCs is limited by their sensitivity to freezing and thawing procedures. Hence, this emerging science needs new, reliable preservation methods for the long-term storage of large quantities of functional hESCs remaining pluripotent after post-thawing and culturing. Here, we present a highly efficient, surface based vitrification method for the cryopreservation of large numbers of adherent hESC colonies, using modified cell culture substrates. This technique results in much better post-thaw survival rate compared to cryopreservation in suspension and allows a quick and precise handling and storage of the cells, indicating low differentiation rates.