Cryopreservation Solution Research Articles

Abstract 22 CellStor Transfer Freezing Bag: Reliable Closed System for Complex Cord Blood Sample Processing and CD34+ Hematopoietic Stem Cell Cryopreservation

IntroductionHematopoietic stem cell (HSC) transplants are effective in the treatment of numerous disorders. Proper processing and storage of umbilical cord blood (UCB) and peripheral blood (PB) HSCs is invaluable for therapeutic applications. Although automated sample processing methods exist, they are unable to accommodate low volume, viscous, fibrin clotted, partially hemolyzed, or otherwise complex samples, resulting in the loss of precious HSCs. The CellBios single-use transfer freezing bag was designed to process peripheral and cord blood samples and freeze HSCs, including from those with the above-mentioned problems. Here we demonstrate the utility of these transfer freezing bags to salvage problematic UCB samples and recover precious HSC material suitable for banking and therapeutics.ObjectiveThe objective of this study was to develop a closed UCB sample processing and cryopreservation solution that is amenable to easy manual operation, can deliver excellent HSC viability and recovery, can eliminate contaminating red blood cells (RBCs), and is capable of processing complex/defective starting samples that are incompatible with conventional automated processing systems into therapeutic grade HSC banks.MethodsWe studied 100 randomly selected UCB samples, from various centers throughout India, that were processed and prepared for cryopreservation using our transfer freezing bag. We recorded the pre- and post-sample processing volumes, total nucleated cell counts (TNCC), hematocrit (HCT), CD34+ cell viability, and recovery.ResultsStudy results showed the following: 94% vs 98% CD34+ cell viability post processing, 77% vs 85% total mononuclear cell viability, 69% vs 85% TNCC recovery in problematic vs normal samples, respectively. It was possible to achieve low RBC carryover –91% HCT reduction post-processing in normal samples; more importantly, problematic samples also had RBC removal evidenced by HCT reduction of 45%.DiscussionWe have demonstrated efficient removal of RBCs to alleviate post-transplantation issues and maximized CD34+ HSC recovery in both normal and problematic UCB samples. Crucially, it was possible to salvage precious CB HSCs from defective samples that would be lost had they been processed in conventional automated workflows. The CellBios CellStor Transfer Freezing Bag Set offers best in class performance in preparing umbilical cord blood samples for cryostorage.

Dimethyl sulfoxide-free cryopreservation solution containing trehalose, dextran 40, and propylene glycol for therapy with human adipose tissue-derived mesenchymal stromal cells

We evaluated a dimethyl sulfoxide (Me2SO)-free cryopreservation solution to freeze human adipose-derived mesenchymal stromal cells (hADSCs). In the first experiment, we compared the combined effects of 3% trehalose (3 T) and 5% dextran (5D) in lactated Ringer’s solution (LR) as a cryopreservation base solution containing 10% propylene glycol (PG). The cell viability of hADSCs immediately after thawing was significantly higher (p < 0.05) in LR supplemented with 3 T (LR-3 T) and with 3 T and 5D (LR-3 T-5D) than in LR. In the second experiment, we compared the cell characteristics of hADSCs freeze-thawed in LR-3 T-5D containing either 10% Me2SO or 10% PG. The cell viability, annexin V-positive ratio, colony-forming capacity, cell proliferation, cell surface antigen positivity, adipogenic differentiation, osteogenic differentiation, and genetic response to cytokine stimulation of hADSCs immediately after thawing were similar between the LR-3 T-5D containing 10% Me2SO and 10% PG. In the third experiment, we examined various concentrations of PG on the cell proliferative capacity of freeze-thawed hADSCs. The cell proliferative capacity of hADSCs frozen with LR-3 T-5D containing 2.5% to 5% PG was significantly higher (p < 0.05) than LR-3 T-5D containing 10% PG. Furthermore, the cell proliferative capacity of hADSCs frozen with LR-3 T-5D containing 4% PG was similar to that of fresh hADSCs. These results indicate that the combination of 3 T-5D in an LR solution as a basic solution is effective for post-thaw cell viability, and that the optimal concentration of PG to maintain the cell characteristics of hADSCs frozen with LR-3 T-5D is 2.5% to 5%, which is promising for cell therapy applications.

Synthesis of Poly(2-(methylsulfinyl)ethyl methacrylate) via Oxidation of Poly(2-(methylthio)ethyl methacrylate): Evaluation of the Sulfoxide Side Chain on Cryopreservation.

Conventional cryopreservation solutions rely on the addition of organic solvents such as DMSO or glycerol, but these do not give full recovery for all cell types, and innovative cryoprotectants may address damage pathways which these solvents do not protect against. Macromolecular cryoprotectants are emerging, but there is a need to understand their structure-property relationships and mechanisms of action. Here we synthesized and investigated the cryoprotective behavior of sulfoxide (i.e., "DMSO-like") side-chain polymers, which have been reported to be cryoprotective using poly(ethylene glycol)-based polymers. We also wanted to determine if the polarized sulfoxide bond (S+O- character) introduces cryoprotective effects, as this has been seen for mixed-charge cryoprotective polyampholytes, whose mechanism of action is not yet understood. Poly(2-(methylsulfinyl)ethyl methacrylate) was synthesized by RAFT polymerization of 2-(methylthio)ethyl methacrylate and subsequent oxidation to sulfoxide. A corresponding N-oxide polymer was also prepared and characterized: (poly(2-(dimethylamineoxide)ethyl methacrylate). Ice recrystallization inhibition assays and differential scanning calorimetry analysis show that the sulfoxide side chains do not modulate the frozen components during cryopreservation. In cytotoxicity assays, it was found that long-term (24 h) exposure of the polymers was not tolerated by cells, but shorter (30 min) incubation times, which are relevant for cryopreservation, were tolerated. It was also observed that overoxidation to the sulfone significantly increased the cytotoxicity, and hence, these materials require a precision oxidation step to be deployed. In suspension cell cryopreservation investigations, the polysulfoxides did not increase cell recovery 24 h post-thaw. These results show that unlike hydrophilic backboned polysulfides, which can aid cryopreservation, the installation of the sulfoxide group onto a polymer does not necessarily bring cryoprotective properties, highlighting the challenges of developing and discovering macromolecular cryoprotectants.

Freezing for the Future: Obtaining Fibroblast Samples from Deceased Wild Mammals for the Brazilian Cerrado Germplasm Bank.

We isolated and further characterized fibroblasts obtained from postmortem skin biopsies of three different Brazilian wild species (Chrysocyon brachyurus-maned wolf, Cerdocyon thous-crab-eating fox, Mazama gouazoubira-brown brocket deer). The effects of two cryoprotectants, 10% dimethyl sulfoxide (DMSO) and 5% dimethylformamide (DMF), were assessed to determine the most efficient cryopreservation protocol. Such an investigation promotes the creation of germplasm banks, using samples that would otherwise be rejected and permanently lost following the death of the animals. We utilized animal corpses that were involved in highway accidents, found dead in the natural environment, or referred to us from the veterinary hospital at the Brasília Zoo. Fibroblasts from C. brachyurus specimens presented a delay in cell growth in Dulbecco's modified Eagle's medium in relation to other species. This observation is a limiting factor for the future storage of cells from this species. Differences in cellular morphology were observed between C. brachyurus, C. thous, and M. gouazoubira, presenting branched, fusiform, and spherical forms, respectively. The cryoprotective solution containing 10% DMSO was more efficient than 5% DMF medium in preserving the viability of fibroblasts of the three species (p < 0.05). After defining the best cryopreservation solution, a germplasm bank was successfully formed. This biological reservoir is configured as the first germplasm bank containing somatic cells and gametes of wild mammals of the Cerrado biome of Brazil. This material will be used for future characterization of the species and multiplication by means of nuclear transfer cloning.

Development of a serum-free, chemically-defined workflow solution for T cell culture

Abstract Cancer immunotherapy has become one of the most promising fields in the treatment of oncologic related disorders, by harnessing the power of T-cells. Expansion and/or differentiation of cells with the right therapeutic profiles, in a consistent and safe manner, requires the use of defined cell culture reagents. One major cause of variability is serum, with its undefined composition. The presence of undefined reagents can lead to the inability to reproduce results between labs, and stop the progression from discoveries to clinical applications. Here we introduce a chemically-defined serum substitute and a low DMSO cryopreservation solution specially designed for T cells. After identifying the essential cell property parameters, and establishing appropriate cell culture assays, we initiated formulation optimization. We were able to identify the critical components required for appropriate cell expansion and cryopreservation. We were able to develop a chemically-defined solution, comparable in performance to serum, while bringing the benefits of being fully defined. We were also able to develop a low DMSO cryopreservation solution, tailored for T cell applications, comparable in performance to home brew or other commercially available solutions containing 10% DMSO. Our development work was allowed to gain in depth knowledge of the impact of each component in T cell biology, allowing us at BioLegend to provide custom tailored solutions. The development of defined reagents provides a smooth transition and reproducibility between research and clinical development.

The effect of glycerol as a cryoprotective agent in the cryopreservation of adipose tissue

BackgroundLong-term preservation of adipose tissue is crucial for clinical applications. Researchers should consider both efficiency and biosafety when choosing a cryoprotective agent (CPA) for adipose tissue preservation. Glycerol has been applied as a nontoxic CPA for multiple tissues but not adipose tissue. We aimed to evaluate the efficacy of glycerol as a CPA for adipose tissue cryopreservation.MethodsFresh human adipose tissues were obtained from patients who underwent liposuction and divided into 1 mL samples. Each sample was randomly mixed with 1 mL of CPA: 60–100% glycerol, 0.25 mol/L trehalose or DMSO + FBS and cryopreserved in − 196 °C liquid nitrogen for one month. After thawing and elution, the tissues were immediately evaluated for activity and structural integrity in vitro. Then, 0.2 mL of each sample was transplanted subdermally to the nude mouse dorsum and harvested after one month for histological examination to assess the effect of the cryopreserved fat in transplantation.ResultsAfter cryopreservation, the samples treated with DMSO + FBS, trehalose, 60% and 70% glycerol had a more integrated structure than the samples in other groups. Tissues preserved with 70% glycerol had the highest G3PDH activity of 24.41 ± 0.70, comparable to 24.76 ± 0.48 in fresh tissue (p > 0.05). Adipose-derived stem cells (ASC) viability, proliferation and differentiation capability were also better preserved in 70% glycerol group. In vivo analysis showed that tissue preserved with 70% glycerol had a retention rate of 52.37 ± 7.53%, significantly higher than other groups. Histological observation demonstrated better structural integrity and viability in 70% glycerol group. Compared to the DMSO + FBS and trehalose groups, the glycerol groups showed lower tissue inflammation.ConclusionGlycerol (70%) is efficient in adipose tissue cryopreservation. Glycerol-based CPAs, which are nontoxic and show biosafety, are a promising solution for clinical tissue cryopreservation.

The effect of betaine for mouse sperm cryopreservation

Sperm cryopreservation is an effective method of preserving male fertility in humans, as well as domestic and experimental animals. However, various factors such as ice crystal formation, osmotic stress, and oxidative stress, negatively influence the motility and viability of post-thawed spermatozoa. Betaine, which works as an osmoprotectant is known to work as a nontoxic cryoprotectant. However, the protective effects during mouse sperm cryopreservation are still unclear. Thus, the purpose of this study was to investigate whether betaine has protective effects during the process of mouse sperm cryopreservation. In this study, betaine was found to be effective in maintaining sperm motility during the freezing procedure and 1% (85.4 mM) betaine was identified as the optimal concentration to be added to cryopreservation solutions. It was also found that betaine improves the integrity of the plasma membranes of sperm tails, suggesting that betaine has a positive effect on sperm motility.

Establishment of a New Cryopreservation Solution for Chimeric Antigen Receptor T Cells.

Preservation and transportation are essential for the clinical application of chimeric antigen receptor T (CAR-T) cells. This study aimed to optimize a cryopreservation solution for CAR-T cells and evaluate the antitumor efficiency of CAR-T cells using this optimized solution in vitro and in vivo. First, the stability of the cryopreservation solution for CAR-T infusion was detected by the L27 (37) orthogonal experiment. Subsequently, osmolality and pH were analyzed for the preservation reagent. Additionally, apoptosis and CAR expression of CAR-T cells were measured by flow cytometry, and the cytotoxicity was determined by calcein-AM staining. The results showed that cryopreservation solutions used in this study demonstrated high chemical stability, which induced only 2% CAR-T cells apoptosis in optimal solutions, which were slightly lower than other commercial solutions. Moreover, the CAR expression was not significantly affected by preservation with these solutions. There were no significant differences in the cytotoxicity between fresh and thawed CAR-T cells cryopreserved in the cryopreservation solutions in vivo and in vitro. This study developed a new cryopreservation solution for CAR-T cells, and it was safe and also had negligible effects on the CAR-T cells antitumor activity.

A Simple Cryopreservation Method for Efficient Isolation of Live Cells from Dead Animals

Cryopreservation of somatic tissues and cells can be applied to biodiversity conservation. Although vitrification is widely used for tissue cryopreservation, it is challenging to obtain viable cells in facilities that lack adequate experimental tools, such as zoos. In this study, we established a simple tissue cryopreservation method for obtaining viable cells. Using mouse tissues of the ears and skin, we explored the conditions suitable for cryopreservation. After freezing, the tissues were thawed, and the cells were isolated. The tissues were then cut into small pieces to obtain viable cells. The use of a cryopreservative solution and freezing at –80°C increased the probability of obtaining viable cells. Viable cells were obtained and cultured even after the ear tissues were stored at room temperature for 24 h. Our method allowed primary cells to be isolated and cultured from ear tissues of dead animal. Further, we examined whether cells isolated from cryopreserved tissues could be studied in vitro. We found that treatment with lipopolysaccharides and Poly I:C increased the mRNA expression of pro-inflammatory cytokines in wild boar cells. These data suggest that the simple cryopreservation method developed here can be applied to biodiversity conservation and basic science studies of wild animal cells.

Vitrification Solutions for Plant Cryopreservation: Modification and Properties.

Many plants cannot vitrify themselves because they lack glassy state-inducing substances and/or have high water content. Therefore, cryoprotectants are used to induce vitrification. A cryoprotectant must have at least the following primary abilities: high glass-forming property, dehydration strength on a colligative basis to dehydrate plant cells to induce the vitrification state, and must not be toxic for plants. This review introduces the compounds used for vitrification solutions (VSs), their properties indicating a modification of different plant vitrification solutions, their modifications in the compounds, and/or their concentration. An experimental comparison is listed based on the survival or regeneration rate of one particular species after using more than three different VSs or their modifications. A brief overview of various cryopreservation methods using the Plant Vitrification Solution (PVS) is also included. This review can help in alert researchers to newly introduced PVSs for plant vitrification cryoprotocols, their properties, and the choice of their modifications in the compounds and/or their concentration.

Gene expression analysis of human induced pluripotent stem cells cryopreserved by vitrification using StemCell Keep

In recent years, regenerative medicine research using human somatic and induced pluripotent stem cells has advanced considerably, promoting clinical applications. However, it is essential that these cells are cryopreserved safely and effectively. Most cryopreservation solution agents contain dimethyl sulfoxide (DMSO), which exhibits strong toxicity and can potentially promote cell differentiation. Hence, it is important to explore substitutes for DMSO in cryoprotectant solutions. One such alternative is StemCell Keep (SCK), a DMSO-free solution that has been reported to effectively cryopreserve human induced pluripotent stem cells (hiPS cells). To clarify the effect of cryopreservation agents on cells, DNA microarray analysis is useful, as it can identify a large number of gene expression differences in cryopreserved cells, as well as functional increases in gene groups. In this study, we performed gene expression analysis of SCK-cryopreserved hiPS cells using a DNA microarray gene chip. The hiPS cells vitrified with SCK or DMSO-based vitrification solutions were thawed and cultured on Matrigel under feeder-free conditions, and RNA was extracted for DNA microarray analysis. Genes obtained from DNA microarray data were classified by the keywords of Gene Ontology Biological Process Term, and their relationships were analyzed using DAVID or the GeneMANIA database.SCK-cryopreserved hiPS cells expressed several anti-apoptotic genes, as well as genes related to cell adhesion or proliferation at levels that were nearly equivalent to those of non-frozen hiPS cells. Gene enrichment analysis with selected genes of SCK-cryopreserved hiPS cells whose expression differences were superior to those of DAP-cryopreserved showed strong interactions of negative regulation of apoptotic process, cell adhesion and positive regulation of cell proliferation in DAVID analysis. We demonstrated that SCK successfully maintained the key functions of hiPS cells, including anti-apoptosis, cell adhesion, and cell proliferation, during cryopreservation.

Dimethyl sulfoxide-free cryopreservation solutions for hematopoietic stem cell grafts

Background aimsThe use of effective methods for the cryopreservation of hematopoietic stem cells (HSCs) is vital to retain the maximum engraftment activity of cord blood units (CBUs). Current protocols entail the use of dimethyl sulfoxide (DMSO) as intracellular cryoprotective agent (CPA) and dextran and plasma proteins as extracellular CPAs, but DMSO is known to be cytotoxic, and its infusion in patients is associated with mild to moderate side effects. However, new, commercially available, DMSO-free cryopreservation solutions have been developed, but their capacity to protect HSCs remains poorly investigated. MethodsHerein the authors compared the capacity of four DMSO-free freezing media to cryopreserve cord blood (CB) HSCs: CryoProtectPureSTEM (CPP-STEM), CryoScarless (CSL), CryoNovo P24 (CN) and Pentaisomaltose (PIM). Clinical-grade DMSO/dextran solution was used as control. ResultsOf the four cryopreservation solutions tested, the best post-thaw cell viability, recovery of viable CD45+ and CD34+ cells and potency were achieved with CPP-STEM, which was equal or superior to that seen with the control DMSO. CSL provided the second best post-thaw results followed by PIM, whereas CN was associated with modest viability and potency. Further work with CPP-STEM revealed that CB CD34-enriched HSCs and progenitors cryopreserved with CPP-STEM maintained high viability and growth expansion activity. In line with this, a pilot transplantation assay confirmed that CPP-STEM-protected CB grafts supported normal short- and long-term engraftment kinetics. ConclusionsThe authors’ results suggest that new, valuable alternatives to DMSO are now available for the cryopreservation of HSCs and grafts, including CBUs.

Role of Liquid-Liquid Phase Transitions in Mechanism of Erythrocyte Protection During Cooling with CRIHBT-115 Cryopreservative Agent

The presence in the system of critical liquid-liquid phase transition (PT) by the mechanism, resulting in formation of dispersion system, namely high-concentrated emulsion, has been established here during cooling when using polarized light microscopy and fixation of critical opalescence phenomenon in erythrocyte concentrate with glycerol-containing cryopreservative agent, designed at the Central Research Institute of Haematology and Blood Transfusion (Russia) (CRIHBT-115 ). The studied cryobiological system displayed no signs of crystallization. A phase behaviour of cryopreservative and supernatant has been studied during cooling-warming cycle. Changes in the volume of cryopreservative and erythrocyte concentrate were comparatively and qualitatively evaluated during cooling. The mechanism of protective action of cryopreservation solution has been determined. The similarity between physical and chemical processes during cooling-warming of erythrocyte cytoplasm and garlic meristem cells (germinal plant tissue) when entering cold anabiosis has been established.

Slow-delivery and distributed exchange of cryoprotective agents with hydrogel beads

Intracellular loading of cryoprotective agents (CPAs) into target cells is a critical step for cryopreservation. However, biological membranes are usually much less permeable to CPAs than to water, resulting in high osmotic pressures and osmotic damage during the CPA loading and unloading phases of cryopreservation. Here, we show that calcium alginate hydrogel beads several millimeters in diamater containing CPAs can be admixed with a cell suspension to spontaneously release CPAs in a gradual and distributed manner. We demonstrate that beads containing cell media enable the gradual removal of CPA from Jurkat cells equilibrated in a typical cryopreservation solution of 15% glycerol, protecting the cells from hypotonic damage. We show that the dynamics of CPA exchange are accurately described by a numerical model of free diffusion within the gel. This approach may enable semiautomated and closed methods of gradual CPA exchange from large volume cell suspensions.

Sperm characterization and cryopreservation of the endangered freshwater fish Chirostoma estor (Atheriniformes)

The knowledge of the physiology of sperm of an endangered species allows the implantation of reproductive biotechnologies that aim at conservation. The aim of this study was to characterize fresh sperm and evaluate different cryopreservation solutions for sperm in Chirostoma estor. The characterization of Chirostoma estor fresh sperm (n = 22 males) was performed through analyzes of sperm concentration, membrane integrity, sperm morphology, motility rate, motility quality score, and motility duration. For cryopreservation (n = 42 males), 3 extenders (BTS™, MIII™, or Androstar Plus™) in combination with 2 permeable cryoprotectants (dimethyl sulfoxide (DMSO) or methyl glycol (Methyl)) were used. Analyzes of post-thaw sperm were performed as described for fresh sperm and additionally the fertilization rate analysis was performed. Fresh sperm presented a sperm concentration of 29.2 × 109 spermatozoa/mL, membrane integrity of 82.4%, and morphologically normal cells of 53%. After glucose activation (150 mM) a motility rate of 87.5%, sperm quality score of 5.0, and a duration of motility of 285 s were observed. For post-thaw sperm, MIII + Methyl and Androstar + Methyl solutions resulted in the highest motility rates of 40–48%. No differences were observed for motility duration, membrane integrity, and sperm morphology. Samples cryopreserved in Methyl (12–20%) showed a higher fertilization rate than DMSO, independently of the extender. In conclusion, the fresh sperm collected artificially from Chirostoma estor presents a compatible quality to carry out fertilization and can be cryopreserved in the commercial extenders MIII™ and Androstar Plus™ together with the cryoprotectant Methyl glycol.

Ultrastructural changes in the spinal cord of rats with experimental allergic encephalomyelitis under the influence of human umbilical cord-derived multipotent mesenchymal stromal cells cryopreserved according to different protocols

The transplantation of multipotent mesenchymal stromal cells (MMSCs) is considered to be a possible therapy of multiple sclerosis. For the clinical application of human umbilical cord-derived MMSCs (UC-MMSCs) it is necessary to develop a method of their cryopreservation taking into account the type of cryoprotective media and to investigate the possibility of using these cells for therapeutic purposes in vivo. The purpose of the study was to investigate the effect of UC-MMSCs, cryopreserved in solutions of different composition, on the processes of demyelination and remyelination of the spinal cord of rats with experimental allergic encephalomyelitis (EAE) as a model of multiple sclerosis. Materials and methods. The EAE was modeled by subcutaneous administration of homogenized spinal cord of adult rats with complete Freund's adjuvant. On the 18th day rats with moderate relapsing-remitting form of EAE were suboccipitally injected 1•106 UC-MMSCs, cryopreserved in cryoprotective media containing dimethyl sulfoxide (DMSO), fetal bovine serum (FBS), ethylene glycol, trehalose and sucrose at different composition. On the 35th and 60th days, the studies of ultrastructural changes of the lumbar spinal cord (L3-L5) were performed, assessing the degree of demyelination of nerve fibers by the ratio of myelin sheath (MS) thickness to the diameter of the axis cylinder (AC) of axons. Results. In rats with moderate EAE from the 35th to the 60th day after the modelling of the disorder, destructive changes and signs of demyelination in the spinal cord increased; the MS/AC index corresponded to the average degree of axon demyelination. Suboccipitally administered cryopreserved UC-MMSCs to EAE rats, depending on the used cryopreservation solution, slowed or stopped the demyelination, decreased the MS/AC index to a low degree of axonal demyelination. Reducing the concentration of DMSO in the cryopreservation medium from 10 % to 4 % and adding 6 % trehalose provided a better effectiveness of UC-MMSCs in decreasing the degree of demyelination in EAE. At the same time, the standard solution (10 % DMSO, 90 % FBS) provided these effect, but to a lesser extent. The use of a multicomponent cryopreservation medium containing 15 % ethylene glycol, 3 % DMSO, 10 % sucrose, 12 % trehalose and 60 % FBS did not achieve the goal of maintaining the effects of UC-MMSCs to reduce the degree of demyelination in EAE. Conclusions. To maintain the therapeutic properties of UC-MMSCs, it is advisable to add a reduced concentration of DMSO (4 %) and 6 % trehalose to the cryopreservation medium, supplemented with 90 % fetal bovine serum.

Evaluation of cryopreservation solutions based on human platelet lysate for bioengineered tissues aimed for advanced therapy treatments

Evaluation of cryopreservation solutions based on human platelet lysate for bioengineered tissues aimed for advanced therapy treatments

Antifreeze Protein Improves the Cryopreservation Efficiency of Hosta capitata by Regulating the Genes Involved in the Low-Temperature Tolerance Mechanism

In this study, whether the addition of antifreeze protein (AFP) to a cryopreservative solution (plant vitrification solution 2 (PVS2)) is more effective in reducing freezing injuries in Hosta capitata than PVS2 alone at different cold exposure times (6, 24, and 48 h) is investigated. The upregulation of C-repeat binding factor 1 (CBF1) and dehydrin 1 (DHN1) in response to low temperature was observed in shoots. Shoots treated with distilled water (dH2O) strongly triggered gene expression 6 h after cold exposure, which was higher than those expressed in PVS2 and PVS2+AFP. However, 24 h after cold exposure, gene expressions detected in dH2O and PVS2 treatments were similar and higher than PVS2 + AFP. The expression was highest in PVS2+AFP when the exposure time was extended to 48 h. Similarly, nitric reductase activities 1 and 2 (Nia1 and Nia2) genes, which are responsible for nitric oxide production, were also upregulated in low-temperature-treated shoots, as observed for CBF1 and DHN1 expression patterns during cold exposure periods. Based on the gene expression patterns, shoots treated with PVS2+AFP were more likely to resist cold stress, which was also associated with the higher cryopreservation efficiency of PVS2+AFP compared to PVS2 alone. This finding suggests that the improvement of cryopreservation efficiency by AFP could be due to the transcriptional regulation of CBF1, DHN1, Nia1, and Nia2, which might reduce freezing injuries during cryopreservation. Thus, AFP could be potentially used as a cryoprotectant in the cryopreservation of rare and commercially important plant germplasm.

Effects of Cryopreservation on Gene Expression and Post Thaw Sperm Quality of Pacific Abalone, Haliotis discus hannai

Pacific abalone, Haliotis discus hannai, is a high commercial seafood in South-East Asia. The aim of the present study was to determine effects of cryopreservation on gene expression and post thaw sperm quality of Pacific abalone. Two ions, Na+ (459.1 ± 3.1 mM) and Cl– (515.9 ± 1.1 mM), were predominant in the seminal plasma (pH: 6.8 ± 0.1; osmolarity: 1,126 ± 3 mOsmL–1). Cryopreservation reduced mRNA expression levels of protein kinase A (PKA-C) and heat shock proteins (HSP70 and HSP90) genes in sperm. Fluorescent technique was used to compare morphological defects, acrosome integrity (AI), plasma membrane integrity (PMI), mitochondrial membrane potential (MMP), and DNA integrity of sperm cryopreserved with five different cryopreservation solutions (8% Me2SO, 8% EG, 6% PG, 2% GLY, and 2% MeOH). Droplet in tail and coiled tail defects was not observed for sperm cryopreserved with 8% Me2SO or 2% GLY. Sperm cryopreserved with 8% Me2SO showed improved DNA integrity and lower cryodamage than sperm cryopreserved with other cryoprotectants. Sperm to egg ratio of 10,000:1 was found to be the most suitable ratio for in vitro fertilization among different ratios tested. The fertilization rate of sperm cryopreserved with 8% Me2SO was not significantly (p &amp;gt; 0.05) different from that of sperm cryopreserved with 2% GLY. DNA fragmentation showed strongly negative relationships with sperm quality parameters. Sperm cryopreserved with 8% Me2SO showed higher post thaw quality and mRNA expression of sperm motility associated gene than those cryopreserved with other cryoprotectants. The present research suggests to use 8% Me2SO for cryopreservation of Pacific abalone sperm as well as for hatchery production.

Optimization of Spheroid Colony Culture and Cryopreservation of Nucleus Pulposus Cells for the Development of Intervertebral Disc Regenerative Therapeutics

After the discovery of functionally superior Tie2-positive nucleus pulposus (NP) progenitor cells, new methods were needed to enable mass culture and cryopreservation to maintain these cells in an undifferentiated state with high cell yield. We used six types of EZSPHERE® dishes, which support spheroid-forming colony culture, and examined NP cell spheroid-formation ability, number, proliferation, and mRNA expression of ACAN, COL1A2, COL2A1, and ANGPT1. Six different types of cryopreservation solutions were examined for potential use in clinical cryopreservation by comparing the effects of exposure time during cryopreservation on cell viability, Tie2-positivity, and cell proliferation rates. The spheroid formation rate was 45.1% and the cell proliferation rate was 7.75 times using EZSPHERE® dishes. The mRNA levels for COL2A1 and ANGPT1 were also high. In cryopreservation, CryoStor10 (CS10) produced ≥90% cell viability and a high proliferation rate after thawing. CS10 had a high Tie2-positive rate of 12.6% after culturing for 5 days after thawing. These results suggest that EZSPHERE enabled colony formation in cell culture without the use of hydrogel products and that CS10 is the best cryopreservation medium for retaining the NP progenitor cell phenotype and viability. Together, these data provide useful information of NP cell-based therapeutics to the clinic.