Cryopreservation: An Overview of Principles and Cell-Specific Considerations

Bovine oocyte vitrification and recovery with ethylene glycol and either propylene glycol or dimethyl sulfoxide

Cryopreservation of female gametes allows for preservation and transportation of superior genetics; however, cryoinjury and cryoprotectant toxicity often affects the viability of oocytes that do survive the procedure due to the use of suboptimal protocols designed for embryo cryopreservation. With significant differences in cryoprotectant sensitivity and plasma membrane permeability between oocytes and embryos, there is a continued need to develop protocols accounting for the unique physiology of oocytes. In this study, oocyte recovery after vitrification with ethylene glycol and either dimethyl sulfoxide or propylene glycol were evaluated with reduced equilibration time compared to prior studies. In mature oocytes thawed after cryopreservation with the combination of dimethyl sulfoxide and ethylene glycol displayed increased mitochondrial membrane potential and reduced reactive oxygen species compared to those cryopreserved with propylene glycol and ethylene glycol (P < 0.05). The combination of propylene glycol and ethylene glycol only displayed improved recovery of the meiotic spindle measured by microtubule arrangement and chromosome distribution (P < 0.05). There were no differences in adenosine triphosphate (ATP) concentration or the number of ATP-depleted oocytes between those cryopreserved with dimethyl sulfoxide or propylene glycol (P > 0.05). Both mitochondrial and meiotic spindle functionality are vital for embryo development, and the concentration of cryoprotectants required to achieve vitrification affects both aspects of oocyte physiology. Further improvements to oocyte vitrification protocols are necessary to minimize damage induced during the procedure and improve reliability of the technology.

Expanding the cryoprotectant toolbox in biomedicine by multifunctional antifreeze peptides

The global cryopreservation market size rises exponentially due to increased demand for cell therapy-based products, assisted reproductive technology, and organ transplantation. Cryoprotectants (CPAs) are required to reduce ice-related damage, osmotic cell injury, and protein denaturation. Antioxidants are needed to hamper membrane lipid peroxidation under freezing stress, and antibiotics are added to the cryo-solutions to prevent contamination. The vitrification process for sized organs requires a high concentration of CPA, which is hardly achievable using conventional penetrating toxic CPAs like DMSO. Antifreeze peptides (AFpeps) are biocompatible CPAs leveraging inspiration from nature, such as freeze-tolerant and freeze-avoidant organisms, to circumvent logistic limitations in cryogenic conditions. This study aims to introduce the advances of AFpeps with cell-penetrating, antioxidant, and antimicrobial characteristics. We herein revisit the placement of AFpeps in the biobanking of cancer cells, immune cells, stem cells, blood cells, germ cells (sperms and oocytes), and probiotics. Implementing low-immunogenic AFpeps for allograft cryopreservation minimizes HLA mismatching risk after organ transplantation. Applying AFpeps to formulate bioinks with optimal rheology in extrusion-based 3D cryobiopriners expedites the bench-to-beside transition of bioprinted scaffolds. This study advocates that the fine-tuned synthetic or insect-derived AFpeps, forming round blunt-shape crystals, are biomedically broad-spectrum, and cell-permeable AFpeps from marine and plant sources, which result in sharp ice crystals, are appropriate for cryosurgery. Perspectives of the available room for developing peptide mimetics in favor of higher activity and stability and peptide-functionalized nanoparticles for enhanced delivery are delineated. Finally, antitumor immune activation by cryoimmunotherapy as an autologous in-vivo tumor lysate vaccine has been illustrated.

Use of polyethylene glycol as an alternative to optimal cutting temperature medium in freeze sectioning for plant histochemical studies

Plant anatomical and histochemical studies are concerned with the structural organization of tissues as well as localization of various metabolites and enzyme activity inside cells and tissues. Traditionally, rotary microtomes are used for paraffin and resin-embedded samples which provide excellent preservation of tissue morphology but removes enzymes, lipid components, and various specialized metabolites. Freeze sectioning apparently remained unexplored in plant histology because of the presence of rigid cell walls and highly vacuolated cytoplasm in plant tissues. In this study, we have described a simple cryostat-based sectioning technique using polyethylene glycol (PEG) as embedding medium after glycerol infiltration that protects the plant tissues from freezing and thawing damage. We have also compared the suitability of inexpensive aqueous PEG solution as compared to commercially available optimal cutting temperature (OCT) medium and obtained identical microscopic images. Diverse plant organs from different genera were sectioned to check the application of this method in plant anatomical studies. In all the cases, cross sections were shown to be well preserved similar to paraffin-embedded plant tissues. In addition, histochemical analyses showed retention of metabolites and even enzymes in the tissues, which can make this method an alternate choice in cryo-microtomy replacing the expensive OCT medium.

Sperm cryopreservation protocol for micro-TESE-retrieved sperm

ABSTRACT

Azoospermia is characterized by the absence of sperm in the ejaculate and is categorized into obstructive azoospermia (OA) and nonobstructive azoospermia (NOA). For men with NOA, testicular sperm extraction (TESE) is the only method to obtain sperm for assisted reproductive technology (ART). Given the rarity of these sperm and the unpredictable success of subsequent retrieval attempts, cryopreservation of microdissection-TESE-obtained sperm is essential. Effective cryopreservation prevents the need for repeated surgical procedures and supports future ART attempts. After first delving into the physiological and molecular aspects of sperm cryopreservation, this review aims to examine the current methods and devices for preserving small numbers of sperm. It presents conventional freezing and vitrification techniques, evaluating their respective strengths and limitations in effectively preserving rare sperm, and compares the efficacy of using fresh versus cryopreserved testicular sperm.

Cryopreservation of biological materials: applications and economic perspectives

Cryopreservation is a transformative technology that allows for the long-term storage of biological materials by cooling them to extremely low temperatures at which metabolic and biochemical processes are effectively slowed or halted. Cryopreservation utilizes various techniques to minimize ice crystal formation and cellular damage during freezing and thawing processes. This technology has broad applications in the fields of medicine, agriculture, and conservation, spanning across stem cell research, reproductive and regenerative medicine, organ transplantation, and cell-based therapies, each with significant economic implications. While current techniques and their associated costs present certain challenges, ongoing research advancements related to cryoprotectants, cooling methods, and automation promise to enhance efficiency and accessibility, potentially broadening the technology's impact across various sectors. This review focuses on the applications of cryopreservation, research advancements, and economic implications, emphasizing the importance of continued research to overcome the current limitations.

Flow cytometry reveals constant lymphocyte proportions after long-term cryopreservation of whole blood in TransFix® cell stabilization reagent

Flow cytometry is an important technique for characterization of immune cells, with accurate lymphocyte profiling being essential for clinical diagnostics and research applications. While immediate processing of blood samples is ideal, long-term storage solutions are needed for large-scale studies or settings without immediate access to laboratory facilities. TransFix® is a chemical stabilization solution that allows delayed analysis by preserving cell morphology and surface markers. However, the impact of long-term cryopreservation in TransFix® on lymphocyte integrity remains underexplored. In this study, we evaluated the efficacy of cryopreservation in TransFix® for maintaining the proportions of key lymphocyte subsets, including CD3+ T cells, CD3+CD4+ T helper cells, CD3+CD8+ cytotoxic T cells, CD19+ B cells, and CD16+/CD56+ natural killer cells. Blood samples were cryopreserved in TransFix® for varying time periods, up to 48 months, and compared to fresh samples using flow cytometry. The results show that the proportions of lymphocyte subsets remain stable during cryopreservation for up to 48 months, with no significant differences observed between fresh and cryopreserved samples. This suggests that TransFix® can successfully preserve lymphocyte integrity for long-term storage, providing a reliable option for delayed analysis. These results highlight the usefulness of TransFix® for studies that require extended storage, making it easier to conduct immune monitoring in a wide range of settings.

Advanced Toolboxes for Cryobioprinting Human Tissue Analogs

The increasing demand for biofabricating human tissue analogs for therapeutic applications has encouraged the pursuit of innovative techniques that shift from conventional bioprint-to-use approaches toward instantaneous bioprint-cryopreserve strategies. Such enabling concepts and next-generation technologies open new possibilities for fabricating shelf-ready living constructs for applications in regenerative medicine, preclinical disease modeling, and beyond. The generation of living constructs either for short- or long-term cryostorage requires, however, a careful design of cryoprotective bioinks to maximize biofunctionality and limit cell damage during processing. Gathering on this, herein the most recent updates in cryo(bio)printing technologies are showcased and discussed, along with demonstrative applications of these approaches. The technical toolboxes for designing cryoprotective inks and optimizing freezing/thawing processes are also critically addressed, considering their underlying bioengineering challenges. Realizing the full potential of cryobioprinting is envisioned to unlock the fabrication of increasingly biomimetic tissue constructs and personalized medicine solutions that are readily available, precisely when needed.

Preserving potential: Surgeons as key partners in establishing a living sarcoma biobank for translational research purposes

BACKGROUND

Sarcoma is a rare type of cancer, of which over 70 distinct molecular subtypes are known. Because these tumours are so rare and complex, treatment outcomes have remained similar over the past decades and research is progressing slowly. For these rare cancers, personalised medicine and patient-derived models might pose solutions for therapeutic problems, but researchers depend on clinicians to access fresh, viable tumour tissue.

METHODS

Over the past five years, a bedside-to-bench flow was implemented in Ghent University Hospital for a living biobank of sarcoma tissue to support translational research. All tumour tissue was cryopreserved in cryopreservation medium (90 % foetal bovine serum and 10 % dimethyl sulfoxide) maintaining viability of the tissue.

RESULTS

As of July 2024, this biobank houses 217 sarcoma samples available for model development, biomarker discovery and precision medicine initiatives. The samples were collected from 167 patients, with 40 patients of whom we collected several samples throughout the disease course.

DISCUSSION

With this article, we aim to incentivise surgeons to engage in biobanking initiatives, as they have a unique position with direct access to fresh tumour tissue. We present our biobank and clinical flow that is implemented in daily clinical practice. The primary aim of the biobank is to advance sarcoma research by creating models and sharing data with fellow researchers.

Investigating the Viability of Fat Cells Over 1, 3, and 6 Months After Freezing at -18°C

BACKGROUND

Lipofilling is a natural, low-risk, and long-lasting method for filling, reconstructing, and improving soft tissues such as the face, with minimal discomfort for patients. Many plastic surgeons prefer autologous fat grafting in aesthetic surgery due to its availability, cost-effectiveness, biocompatibility, and absence of allergic and carcinogenic concerns. Despite the advantages of autologous fat injection, one of the main drawbacks is the variable persistence of injected fat tissue. Given the significant implications of this issue in advanced countries, this study aims to investigate the survival of fat cells after freezing at different time intervals (1, 3, and 6 months).

METHODS

Thirty female participants were enlisted for this research, and the viability of fat cell specimens was assessed at intervals of 0, 1, 3, and 6 months post-freezing at -18°C. The evaluation of viable adipocytes was conducted using the XTT assay, a live/dead staining method using fluorescence microscopy after staining with fluorescein diacetate (FDA) and propidium iodide (PI), along with histological analysis of fat tissue after freezing at the indicated time intervals.

RESULTS

The results showed that the viability of frozen fat samples decreases by 34%, 60%, and 80% after 1, 3, and 6 months, respectively, compared to non-frozen samples on Day 0.

CONCLUSIONS

The findings of this study underscore a rapid decline in adipocyte viability after storage at -18°C at different time intervals (1, 3, and 6 months), at which points only around 60%, 40%, and 20% of fat cells remained viable, respectively. These results suggest that current fat preservation techniques utilizing either a -18°C freezer are not sufficient for maintaining the long-term viability of adipocytes, and alternative cryopreservation methods are needed to preserve fat cells.

Clinical experience with cryopreserved mesenchymal stem cells for cardiovascular applications: A systematic review

BACKGROUND

As living biodrugs, mesenchymal stem cells (MSCs) have progressed to phase 3 clinical trials for cardiovascular applications. However, their limited immediate availability hampers their routine clinical use.

AIM

To validate our hypothesis that cryopreserved MSCs (CryoMSCs) are as safe and effective as freshly cultured MSC counterparts but carry logistical advantages.

METHODS

Four databases were systematically reviewed for relevant randomized controlled trials (RCTs) evaluating the safety and efficacy of CryoMSCs from various tissue sources in treating patients with heart disease. A subgroup analysis was performed based on MSC source and post-thaw cell viability to determine treatment effects across different CryoMSCs sources and viability status. Weighted mean differences (WMDs) and odds ratios were calculated to measure changes in the estimated treatment effects. All statistical analyses were performed using RevMan version 5.4.1 software.

RESULTS

Seven RCTs (285 patients) met the eligibility criteria for inclusion in the meta-analysis. During short-term follow-up, CryoMSCs demonstrated a significant 2.11% improvement in left ventricular ejection fraction (LVEF) [WMD (95%CI) = 2.11 (0.66-3.56), P = 0.004, I 2 = 1%], with umbilical cord-derived MSCs being the most effective cell type. However, the significant effect on LVEF was not sustained over the 12 months of follow-up. Subgroup analysis demonstrated a substantial 3.44% improvement in LVEF [WMD (95%CI) = 3.44 (1.46-5.43), P = 0.0007, I 2 = 0%] when using MSCs with post-thaw viability exceeding 80%. There was no statistically significant difference in the frequency of major cardiac adverse events observed in rehospitalization or mortality in patients treated with CryoMSCs vs the control group.

CONCLUSION

CryoMSCs are a promising option for heart failure patients, particularly considering the current treatment options for cardiovascular diseases. Our data suggest that CryoMSCs could be a viable alternative or complementary treatment to the current options, potentially improving patient outcomes.

Comparison of the quality of ovarian tissue cryopreservation by conventional slow cryopreservation and vitrification-a systematic review and meta-analysis

BACKGROUND

Ovarian tissue cryopreservation is increasingly applied in patients undergoing gonadotoxic radiotherapy or chemotherapy treatment or other patients who need to preserve their fertility. However, there is currently limited evidence to know which type of ovarian tissue cryopreservation is better. The advantages and disadvantages of conventional slow cryopreservation and vitrification are still controversial. The purpose of this meta-analysis was to analyze the ovarian tissue quality of ovarian tissue cryopreservation by conventional slow cryopreservation and vitrification.

METHODS

According to the keywords, Pubmed, Embase, and Cochrane Library were searched for studies to January 2024. Studies comparing the follicular viability of conventional slow cryopreservation versus vitrification were assessed for eligibility. The meta-analysis was performed using Stata software (Version 12.0) and Review Manager (Version 5.2).

RESULTS

A total of 18 studies were included in this meta-analysis. The pooled results of the primary outcomes indicated that there was no difference between the two approaches for follicular viability (RR = 0.96, 95% CI: 0.84-1.09, P = 0.520, I2 = 95.8%, Random-effect), the proportion of intact primordial follicles (RR = 1.01, 95% CI: 0.94-1.09, P = 0.778, I2 = 70.6%, Random-effect). The pooled results of the secondary outcomes indicated that there was no difference between the two approaches for the proportion of DNA fragmented follicles (RR = 1.20, 95% CI: 0.94-1.54, P = 0.151, I2 = 0.0%, Fixed-effect), and the proportion of stromal cells (RR = 0.58, 95% CI: 0.20-1.65, P = 0.303, I2 = 99.7%, Random-effect).

CONCLUSIONS

Conventional slow cryopreservation and vitrification appear to provide comparable outcomes. The heterogeneity of the literature prevents us from comparing these two techniques. Further high-quality studies are needed to enhance this statement. This meta-analysis provides limited data which may help clinicians when counselling patients.

Successful cryopreservation of marine invertebrates immune cells enables long-term studies of common octopus, Octopus vulgaris Cuvier 1797, hemocyte immune functions

The common octopus, Octopus vulgaris Cuvier 1797, as all cephalopods, presents highly evolved characteristics compared to other classes of molluscs and the whole invertebrate phyla. However, to date, there is not much information about its immune system, and studying the defense mechanisms is a key step in understanding their response to external aggressions, having the tools to anticipate animal health problems and ensure their welfare. The lack of cell cultures in molluscs is a major problem when carrying out in vitro assays that help to deepen our knowledge of this species' main immune cells. Cryopreservation becomes an alternative to maintaining viable and functional cells after freezing/thawing processes. Having access to good high-quality cells for long periods allows cover a wider repertoire of studies, time courses, and the avoidance of logistical issues such as loss of viability and/or functionality, time constraints, or sample transport challenges. Additionally, high-quality cell suspensions are essential for successful applications, such as single-cell sequencing, where viability and functionality are the key to optimal identification. The optimal medium, cryoprotective agent, and freezing/thawing protocol for octopus hemocytes have been selected. We show here the first functional results from cryopreserved hemocytes. Cells cryopreserved in MAS medium supplemented with EG maintained viability above 80% after 15 weeks post cryopreservation storage at -80°C, and their functional ability to phagocytize bacteria similar to fresh cells. Moreover, thawed acclimated cells exhibited a gene expression pattern comparable to fresh cells, as opposed to directly thawed cells. The acclimation process after thawing was essential to recover the functional activity of the cells and to return to levels of gene expression involved in oxidative stress similar to fresh cells.The results presented here will facilitate functional studies of octopus immune cells and provide tools for cell preservation in other molluscs species.

Reviving hope: unlocking pancreatic islet immortality by optimizing a trehalose-based cryopreservation media and cell-penetrating peptide

BACKGROUND

Diabetes mellitus remains a pervasive global health concern, urging a deeper exploration of islet transplantation as a potential enduring solution. The efficacy of this therapeutic approach pivots on the precision of cryopreservation techniques, ensuring both the viability and accessibility of pancreatic islets. This study delves into the merits of cryopreserving these islets using the disaccharide trehalose, accompanied by an inventive strategy involving poly L proline (PLP) as a cell-penetrating peptide to overcome the cryoprotectant limitations inherent to trehalose.

METHODS

In our experiments with rat islets, we conducted meticulous viability assessments for fresh and frozen samples. We employed a spectrum of methods, including live/dead staining, insulin/glucagon staining, and measurement of reactive oxygen species (ROS) levels. To gauge functional integrity, we executed glucose-stimulated insulin secretion tests. Subsequently, we transplanted thawed islets into diabetic mice to scrutinize their performance in clinically relevant conditions.

RESULTS

Our study yielded compelling results, affirming the successful cryopreservation of pancreatic islets using trehalose and PLP. Viability, as corroborated through live/dead and insulin/glucagon staining, underscored the sustained preservation of frozen islets. Moreover, these preserved islets exhibited functional integrity by releasing insulin responsively to glucose stimulation. Significantly, upon transplantation into diabetic mice, the thawed islets proficiently restored euglycemia, evidenced by a substantial reduction in fasting blood glucose and an enhanced glucose tolerance.

CONCLUSION

Our findings accentuate the potential of trehalose and PLP as sophisticated cryoprotectants for preserving pancreatic islets. Beyond highlighting viability and functionality, the preserved islets demonstrated a remarkable capacity to restore euglycemia post-transplantation. This research holds promise in addressing the inherent limitations of islet transplantation, particularly in the realm of Type 1 diabetes treatment.

No synergistic effect of extracellular cryoprotectants with dimethyl sulfoxide in the conservation of northern tiger cat fibroblasts

The success of somatic cell cryobanks is dependent on establishing reproducible cryopreservation methodologies. We supposed that associated extracellular cryoprotectants (sucrose and L-proline) with 2.5 or 10 % dimethyl sulfoxide (Me2SO) could guarantee better northern tiger cat cells quality rates after thawing when compared to Me2SO alone. Therefore, we evaluated the effects of sucrose or L-proline with 2.5 or 10 % Me2SO on the cryopreservation of northern tiger cat fibroblasts. Somatic cells were also cryopreserved with 2.5 % or 10 % Me2SO alone. All cells were analyzed for morphology, membrane integrity, proliferative activity, metabolism, apoptosis classification, reactive oxygen species (ROS) levels, and mitochondrial membrane potential (ΔΨm). Regardless of the cryoprotective solution, cryopreservation did not affect morphology, membrane integrity after culture, proliferative activity, and metabolism (P > 0.05). However, immediately after thawing, 2.5 % Me2SO with L-proline and 10 % Me2SO promoted higher rates of membrane integrity when compared to the other cryopreserved groups (P < 0.05). Interestingly, cells cryopreserved with 10 % Me2SO maintained ROS levels similar to non-cryopreserved cells (P > 0.05). However, the percentage of viable cells evaluated by apoptosis classification was reduced when using 10 % Me2SO with L-proline compared to non-cryopreserved groups (P < 0.05). Additionally, ΔΨm was altered in all cryopreserved groups (P < 0.05). In summary, sucrose and L-proline were less effective in cryopreservation of northern tiger cat fibroblasts in the presence of 2.5 % or 10 % Me2SO. Also, 10 % Me2SO appears to be the most suitable cryoprotectant for the formation of cryobanks of this species.

Species-specific optimisation of cryopreservation media for goat and buffalo adipose-derived mesenchymal stem cells

Adipose-derived mesenchymal stem cells (ADSCs) are promising for clinical and veterinary applications due to their ease of isolation, high yield, and multilineage differentiation potential. Effective cryopreservation is vital to ensure their availability for large-scale applications. This study evaluated cryopreservation strategies for goat (gADSCs) and buffalo (bADSCs) ADSCs, using combinations of intracellular (dimethyl sulfoxide, DMSO) and exocellular cryoprotectants, including fetal bovine serum (FBS), polyethylene glycol (PEG), trehalose, bovine serum albumin (BSA), and dextran. Post-thaw parameters such as viability, recovery, metabolic activity, clonogenicity, oxidative stress, apoptosis, and senescence were assessed. Results revealed species-specific differences in cryopreservation requirements. gADSCs were optimally preserved in a medium with 5 % DMSO, 3 % FBS, 2 % PEG, 3 % trehalose, and 2 % BSA, while bADSCs performed best in an FBS-free medium containing 5 % DMSO, 2 % PEG, 3 % trehalose, and 2 % BSA. DMSO-FBS formulations supported high recovery and metabolic activity but were associated with increased oxidative stress and apoptosis. Dextran-based cryomedia effectively preserved gADSCs but failed to maintain bADSC functionality. Biochemical composition analysis indicated significantly higher lipid content in bADSCs, likely influencing cryopreservation efficacy. These findings underscore the need for tailored cryopreservation strategies to address species-specific differences. Incorporating exocellular cryoprotectants reduced FBS dependency, minimised oxidative damage, and maintained functional attributes. This study highlights the potential for optimised, cost-effective biobanking solutions that accommodate species-specific requirements, advancing the use of ADSCs in veterinary and translational research.

Eliminating osmotic stress during cryoprotectant loading: A mathematical investigation of solute-solvent transport

Osmotic stresses during cryoprotectant loading induce changes in cellular volume, leading to membrane damage or even cell death. Appropriate model-guided mitigation of these osmotic gradients during cryoprotectant loading is currently lacking, but would be highly beneficial in reducing viability loss during the loading process. To address this need, we reformulate the two-parameter formalism described by Jacobs and Stewart for cryoprotectant loading under the constraint of constant cell volume. We then derive simple, concise, analytic solutions to these equations, showing the transient extracellular permeating and nonpermeating cryoprotectant concentrations required to load a cell at constant volume, thus eliminating osmotic stresses during cryoprotectant loading. Additionally, we show analytic approximations of both ramp (linear) as well as step-wise loading and how one can use the hydraulic conductivity Lp, membrane permeability Ps, cell volume Vo, and osmotically inactive fraction to derive cryoprotectant loading protocols that minimize osmotic stress. We also present timescales for water and cryoprotectant transport which can be used to estimate loading times as well as Lp and Ps. We discuss how previous optimized loading strategies are inherently sensitive to parameter uncertainties and biological variability, increasing the likelihood of exceeding critical osmotic limits. By contrast, the proposed protocol provides a larger buffer against deviations, offering a safer and more robust solution to CPA loading. Importantly, we demonstrate that the volume-loss-free CPA loading protocols outlined in this paper occur on the same timescale as conventional and step-loading methods, suggesting that these protocols could be a safer alternative for CPA loading.

Vitrification of 3D-MSCs encapsulated in GelMA hydrogel: Improved cryosurvival, reduced cryoprotectant concentration, and enhanced wound healing

Compared to traditional 2D-cultured mesenchymal stem cells (MSCs), 3D-MSCs offer distinct advantages in disease treatment. However, large-scale culture of 3D-MSCs remains labor-intensive and time-consuming. Thus, developing cryopreservation method for 3D-MSCs is essential for clinical application. Existing cryopreservation techniques primarily focus on 2D-cultured MSCs, and vitrification methods such as Cryotop are not suitable for large-scale applications, often leading to cytotoxicity due to high concentrations of cryoprotective agents. To address these challenges, we developed an innovative vitrification method using microfluidics, which involved encapsulating 3D human umbilical cord MSCs in GelMA hydrogel to create 3D-MSCs hydrogel microspheres (3D-MSCsHM). This approach significantly enhanced the survival rates of MSCs while reducing the need for cryoprotective agents. The entire process could be completed in 30 min, yielding 96 % viability and functionality upon rewarming. Proteomic analysis further revealed that improved viability and functions post rewarming were linked to enhance mitochondrial function, increased antioxidant proteins, and elevated growth factors. Furthermore, this method showed effective therapeutic outcomes in wound healing in a mouse model, comparable to those achieved with fresh 3D-MSCs. The presented vitrification technique offers a practical solution for the cryopreservation of multicellular stem cell tissues, enhancing their therapeutic applications.

Overview of Glycometabolism of Lactic Acid Bacteria During Freeze-Drying: Changes, Influencing Factors, and Application Strategies

Lactic acid bacteria (LAB) play a vital role in food fermentation and probiotics microeconomics. Freeze-drying (FD) is a commonly used method for preserving LAB powder to extend its shelf life. However, FD induces thermal, osmotic, and mechanical stresses that can impact the glycometabolism of LAB, which is the process of converting carbohydrates into energy. This review explores the effect of FD on glycometabolism, factors influencing glycometabolism, and feasible strategies in the FD process of LAB. During the three stages of FD, freezing, primary drying or sublimation, and second drying, the glycolytic activity of LAB is disrupted in the freezing stage; further, the function of glycolytic enzymes such as hexokinase, phosphofructokinase, and pyruvate kinase is hindered, and adenosine triphosphate (ATP) production drops significantly in the sublimation stage; these enzyme activities and ATP production nearly cease and exopolysaccharide (EPS) synthesis alters during the secondary drying stage. Factors such as strain variations, pretreatment techniques, growth medium components, FD parameters, and water activity influence these changes. To counteract the effects of FD on LAB glycometabolism, strategies like cryoprotectants, encapsulation, and genetic engineering can help preserve their glycometabolic activity. These methods protect LAB from harsh FD conditions, safeguarding glycolytic flux and enzymatic processes involved in carbohydrate metabolism. A deeper understanding of these glycometabolic changes is essential for optimizing FD processes and enhancing the use of LAB in food, medicine, and biotechnology, ultimately improving their performance upon rehydration.

Quality assessment strategy development and analytical method selection of GMP grade biological drugs for gene and cell therapy

Biological drugs with gene and cell therapy potentials, including natural or rationally created biomacromolecules, recombinant proteins/enzymes, gene-carrying DNA/RNA fragments, oncolytic viruses, plasmid and viral vectors or other gene delivering vehicles with specific therapeutic genes and gene manipulation tools, and genetically modified and reprogrammed human cells comprise a large fraction of drug development candidates in modern precision and regeneration medicine. These drugs have displayed unique capabilities in treating patients with previously incurable diseases. However, most of the drug preparations have complex multimolecular structures and require specific biomanufacturing systems and many other additional biological active materials for drug synthesis, cell expansion, and production enhancement. Thus, the final products would have to be subjected to sequential extensive purification processes to exclude impurities and to concentrate the drug products after manufacturing. The quality evaluation for each drug product is an individualized process and must be specifically designed and performed according to the characteristics of the drug and its manufacturing and purification methods. Some of the Quality Control (QC) assays may be very costly and time-consuming, frequently with inconsistent test results from batch-to-batch. This review focuses on QC assessment strategy development for common gene and cell therapy drugs which use prokaryotic or eukaryotic cells for manufacturing or cell factories for in vitro expansions, especially for drug identification and concentration determination, impurity detection and quantification, drug potency, stability, and safety evaluations; and discusses some key issues for drug quality assessments in different categories and emphasizes the importance of individualized QC strategy design.

An all-in-one microfluidic cryopreservation system and protocols with gradually increasing CPA concentration

In regular biosample cryopreservation operations, dropwise pipetting and continuous swirling are ordinarily needed to prevent cell damage (e.g. sudden osmotic change, toxicity and dissolution heat) caused by the high-concentration cryoprotectant (CPA) addition process. The following CPA removal process after freezing and rewarming also requires multiple sample transfer processes and manual work. In order to optimize the cryopreservation process, especially for trace sample preservation, here we present a microfluidic approach integrating CPA addition, sample storage, CPA removal and sample resuspension processes on a 30 × 30 × 4 mm3 three-layer chip. The sample solution could be added into CPA solution with pre-generated increasing concentration to decrease possible osmotic damage. Utilizing specially designed microfluidic structure and fluid field analysis, on-chip sample enrichment and CPA removal were achieved. A novel dead-end micro valve strategy with a simplified control module was applied and evaluated to assist on-chip mixing and sample pellet resuspension. The entire biosample cryopreservation process was also performed that verified the functions of the integrated microfluidic platform. Altogether, this developed platform could be an effective approach to realize automatic, all-in-one, low-damage cryopreservation operation.

The impact of beauvericin on rainbow trout intestinal epithelial cells at different temperatures and dosing methods

Mycotoxins in aquatic feeds and their effects on fish are becoming more important in aquaculture, as fishmeal and fish oil in feeds are being replaced with more sustainable plant protein. Here, we investigated the potential of the mycotoxin, beauvericin (BEA), to impact the rainbow trout (RT) intestine by using cultures of the epithelial cell line, RTgutGC. BEA was dosed in different ways and exposed at temperatures ranging from 4 to 26 °C before being evaluated for cell viability by the metabolic reduction of Alamar Blue, by the accumulation of Neutral Red (lysosomal activity), cytotoxicity (CellTox Green), and for wound healing. BEA induces cell death in RTgutGC cells. The lysosomes are the main target (Neutral Red assay is the most sensitive) while cytotoxicity and plasma membrane rupture (CellTox Green) occur at considerably higher concentrations. BEA caused a dose-dependent decline in Neutral Red reading at all tested temperatures but Alamar Blue readings did not decline at 4 °C. Under these conditions, BEA appears to impair only lysosomal activity. Wound healing was reduced at 4, 10, and 26 °C compared to 18 °C. Also BEA treatment, at non-cytotoxic concentrations, reduced wound healing, but the temperature had little influence on this. Different carrier vehicles (methanol, DMSO) and exposure methods (passive or active dispersal) for BEA exposure were also studied. Here, methanol and passive dispersal gave comparable results to exposure with DMSO and active dispersal. In contrast, when DMSO was dosed with passive dispersal, immediate cytotoxicity in combination with BEA was induced.

Improving rooster semen cryopreservation with telmisartan-enhanced extender

Semen cryopreservation is essential for preserving genetic resources and enabling artificial insemination in poultry breeding. However, avian sperm is known to experience detrimental changes during the freezing process. Telmisartan, an angiotensin-II receptor antagonist recognized for its antioxidant properties and ability to activate AMP-activated protein kinase (AMPK), was hypothesized to improve post-thaw semen quality by enhancing mitochondrial function and providing antioxidant protection to sperm. The current study was conducted to determine the effect of a semen extender containing different levels of Telmisartan on post-thaw rooster sperm quality indices. Ten 30-week-old broiler breeder roosters (Cobb 500) provided semen samples, which were pooled and diluted with extenders containing varying Telmisartan concentrations (0, 7.5, 15, 22.5, 30 µg/ml). The samples were cryopreserved and later evaluated for motility, membrane integrity, mitochondrial activity, antioxidant capacity, and apoptotic-like changes. The addition of Telmisartan at 7.5 and 15 µg/ml significantly improved total motility (TM), progressive motility (PM), average path velocity (VAP), straight linear velocity (VSL), and curvilinear velocity (VCL) compared to the control. The highest improvement was observed at 15 µg/ml, which also showed increased membrane integrity and mitochondrial activity while reducing apoptotic and dead sperm percentages. Antioxidant assays revealed elevated glutathione peroxidase (GPx) and total antioxidant capacity (TAC) levels, alongside decreased malondialdehyde (MDA) levels in the 15 µg/ml group. Higher Telmisartan concentrations (22.5 and 30 µg/ml) did not yield additional benefits and, in some parameters, performed similarly to the control group. The study concludes that Telmisartan, at an optimal concentration of 15 µg/ml, enhances the cryopreservation outcomes for rooster semen by improving motility, mitochondrial function, and antioxidant defense while reducing lipid peroxidation and apoptosis. These findings suggest potential for better fertility rates in poultry breeding programs utilizing Telmisartan-enhanced extenders for semen cryopreservation. Further research is recommended to explore the broader implications of these results on reproductive performance.

Beyond transplants: current and future therapeutic potential of amniotic membrane extract (AME) in ophthalmology

There is no established consensus or standardized method for the preparation of amniotic membrane extract (AME). Consequently, various preparation, preservation, and sterilization techniques have been employed. To obtain AME rich in bioactive components with high therapeutic efficacy, each step of the preparation process is of critical importance. The appropriate procurement of the amniotic membrane minimizes the risk of infection transmission and reduces inter- and intra-donor variability. For the subsequent extraction process, different approaches are utilized due to factors such as laboratory infrastructure variability and the lack of a standardized method. Although lyophilization has recently emerged as a prominent method for the long-term preservation of AME, further investigation is required to assess its impact on the biochemical composition and clinical efficacy of the membrane. In ophthalmology, in vitro, in vivo, and clinical studies indicate that AME supports corneal epithelial regeneration, suppresses inflammation, and is a well-tolerated therapeutic agent. Consequently, further studies are still needed to enhance the effective release of therapeutic components from the amniotic membrane, improve the quality and consistency of AME, and preserve its content over an extended period. Thus, the clinical application of AME-derived products in the form of eye drops will become more widespread in the future.

Insights on the role of cryoprotectants in enhancing the properties of bioinks required for cryobioprinting of biological constructs

Preservation and long-term storage of readily available cell-laden tissue-engineered products are major challenges in expanding their applications in healthcare. In recent years, there has been increasing interest in the development of off-the-shelf tissue-engineered products using the cryobioprinting approach. Here, bioinks are incorporated with cryoprotective agents (CPAs) to allow the fabrication of cryopreservable tissue constructs. Although this method has shown potential in the fabrication of cryopreservable tissue-engineered products, the impact of the CPAs on the viscoelastic behavior and printability of the bioinks at cryo conditions remains unexplored. In this study, we have evaluated the influence of CPAs such as glycerol and dimethyl sulfoxide (DMSO) on the rheological properties of pre-crosslinked alginate bioinks for cryoprinting applications. DMSO-incorporated bioinks showed a reduction in viscosity and yield stress, while the addition of glycerol improved both the properties due to interactions with the calcium chloride used for pre-crosslinking. Further, tube inversion and printability experiments were performed to identify suitable concentrations and cryobioprinting conditions for bioinks containing CPAs & pre-crosslinked with CaCl2. Finally, based on the printability analysis & cell recovery results, 10% glycerol was used for cryobioprinting and preservation of cell-laden constructs at -80 °C and the viability of cells within the printed structures were evaluated after recovery. Cell viability results indicate that the addition of 10% glycerol to the pre-crosslinked bioink significantly improved cell viability compared to bioinks without CPAs, confirming the suitability of the developed bioink combination to fabricate tissue constructs for on-demand applications.

Sperm Cryopreservation in Boars

Cryopreservation is the procedure that allows preserving cells, including gametes, for long time periods while maintaining their functionality, through the use of cryogenic temperature. Currently, sperm cryopreservation is a crucial-assisted reproductive biotechnology in pigs since it is the only effective and efficient method for long-term preservation of boar fertility. Here, we describe a two-step cryopreservation protocol for boar sperm using lactose-egg yolk and glycerol-based extenders.

Trans-Vessel Wall Cell Transplantation, Engraftment, and Tumor Access in the VX2 Rabbit Model

The trans-vessel wall device (TW-device) is a new endovascular tool for precise and safe delivery of various payloads (cells, viral, modified RNA, chemotherapy, growth factors) in oncology and regenerative medicine. The twofold aim of this study was to assess cell engraftment and tumor growth using the TW-device for endovascular transplantation and to evaluate its ability to directly access solid tumors. We used the VX2 model in the rabbit kidney to compare percutaneously implanted fresh VX2 cells with TW-device injections of cryopreserved VX2 cells. We demonstrated the feasibility of endovascular transplantation (n = 7) of tumor cells, achieving a 57.1% engraftment rate despite cryopreservation, comparable with 70% for percutaneous delivery of fresh cells (n = 10). Re-access using the TW-device was 100% successful (n = 11) with super-selective intratumoral contrast administration without complications. In conclusion, endovascular transplantation of VX2 cells using the TW-device resulted in proliferating cell grafts in the rabbit kidney establishing functional proof that cells indeed survive handling, preparation, and device passage. We also show the TW-device is able to access solid tumor parenchyma allowing precise intraparenchymal administration.This proof-of-concept study open up possibilities for repeated direct parenchymal injections via the endovascular route in any hard to reach organ.

A risk-based approach can guide safe cell line development and cell banking for scaled-up cultivated meat production

For commercial viability, cultivated meats require scientifically informed approaches to identify and manage hazards and risks. Here we discuss food safety in the rapidly developing field of cultivated meat as it shifts from lab-based to commercial scales. We focus on what science-informed risk mitigation processes can be implemented from neighbouring fields. We case-study pre-market safety assessments from UPSIDE Foods, GOOD Meat and Vow Group using publicly available dossiers. Quality control and safety assurance practices need to be established and standardized for cell lines and food-grade cell banks.

Establishment and characterization of fibroblast lines from the northern tiger cat (Leopardus tigrinus, Schreber, 1775) during extended passage and cryopreservation

The establishment of fibroblast lines enables several applications from the formation of biobanks for the conservation of biodiversity to the use of these cells in physiological and toxicological assays. Considered a species vulnerable to extinction, the characterization of fibroblastic lines of northern tiger cat would contribute to its conservation. Therefore, we established and characterized fibroblasts derived from northern tiger cat during extended passage (third, seventh, and eleventh passages) and cryopreservation with regard to the morphology, viability, apoptotic classification, metabolism, proliferative activity, and oxidative stress by reactive oxygen species (ROS) levels and mitochondrial membrane potential (ΔΨm). Initially, we identified four dermal fibroblast lines by morphology, immunophenotyping, and karyotyping assays. In vitro culture after the third, seventh, and eleventh passages did not affect the viability, apoptotic classification, and ROS levels. Nevertheless, cells at seventh and eleventh passages featured a reduction in metabolism and an alteration in ΔΨm when compared to third passage cells. Additionally, cells at eleventh passage showed changes in the proliferative activity and morphology when compared to other passages. Regarding cryopreservation, no effect was observed on cryopreserved cells for morphology, viability, apoptotic classification, metabolism, and proliferative activity. Nevertheless, cryopreserved cells had alteration for ROS levels and ΔΨm. In summary, fibroblasts from northern tiger cat were affected by extended passage (seventh and eleventh passages) and cryopreservation. Adjustments to the in vitro culture and cryopreservation are necessary to reduce cellular oxidative stress caused by in vitro conditions.

Beyond the icebox: modern strategies in organ preservation for transplantation

Organ transplantation, a critical treatment for end-stage organ failure, has witnessed significant advancements due to the integration of improved surgical techniques, immunosuppressive therapies, and donor-recipient matching. This review explores the progress of organ preservation, focusing on the shift from static cold storage (SCS) to advanced machine perfusion techniques such as hypothermic (HMP) and normothermic machine perfusion (NMP). Although SCS has been the standard approach, its limitations in preserving marginal organs and preventing ischemia-reperfusion injury (IRI) have led to the adoption of HMP and NMP. HMP, which is now the gold standard for high-risk donor kidneys, reduces metabolic activity and improves posttransplant outcomes. NMP allows real-time organ viability assessment and reconditioning, especially for liver transplants. Controlled oxygenated rewarming further minimizes IRI by addressing mitochondrial dysfunction. The review also highlights the potential of cryopreservation for long-term organ storage, despite challenges with ice formation. These advances are crucial for expanding the donor pool, improving transplant success rates, and addressing organ shortages. Continued innovation is necessary to meet the growing demands of transplantation and save more lives.

Trehalose Cryopreservation of Human Mesenchymal Stem Cells from Cord Tissue

Adequate hypothermic storage of human mesenchymal stem cells (hMSCs) is of fundamental importance since they have been explored in several regenerative medicine initiatives. However, the actual clinical application of hMSCs necessitates hypothermic storage for long periods, a process that requires the use of non-toxic and efficient cryo-reagents capable of maintaining high viability and differentiating properties after thawing. Current cryopreservation methods are based on cryoprotectant agents (CPAs) containing dimethylsulphoxide (DMSO), which have been shown to be toxic for clinical applications. In this study, we describe a simple and effective trehalose (TRE)-based solution to cryo-store human umbilical cord-derived MSCs (UC-MSCs) in liquid nitrogen. Cells viability, identity, chromosomal stability, proliferative and migration capacity, and stress response were assessed after cryopreservation in TRE as CPA, testing different concentrations by itself or in combination with ethylene glycol (EG). Here we show that TRE-stored UC-MSCs provided lower cell recovery rates compared with DMSO-based solution, but maintained good functional properties, stability, and differentiating potential. The best cell recovery was obtained using 0.5 M TRE with 10% EG showing no differences in the osteogenic, adipogenic, and chondrogenic differentiation capacity. A second cycle of cryopreservation in this TRE-based solution had no additional impact on the viability and morphology, although slightly affected cell migration. Furthermore, the expression of the stress-related genes, HSPA1A, SOD2, TP53, BCL-2, and BAX, did not show a higher response in UC-MSCs cryopreserved in 0.5 M TRE + 10% EG compared with DMSO. Together these results, in addition to ascertained therapeutic properties of TRE, provide sufficient evidence to consider TRE-based medium as a low-cost and efficient solution for the storage of human UC-MSCs cells and potentially substitute DMSO-based cryo-reagents.

Positive Effect of Elevated Thawing Rate for Cryopreservation of Human Ovarian Tissue: Transcriptomic Analysis of Fresh and Cryopreserved Cells

Ovarian tissue cryopreservation has been gradually applied. It is essential to elucidate the differences between cryopreserved and fresh ovarian tissue and to refine cryopreservation protocols for improved outcomes. To explore the transcriptomic differences between fresh ovarian tissue and tissue cryopreserved with an elevated thawing rate. Ovarian tissue samples were collected and cryopreserved (frozen and thawed) following RNA sequencing and histological evaluation. Three groups were formed: fresh tissue (Group 1), frozen tissue after quick thawing at 100 °C (Group 2), and frozen tissue after slow thawing at 37 °C (Group 3). KEGG analysis showed that in comparison with Group 1, DEGs in Group 2 were mainly enriched in the cortisol synthesis and ovarian steroidogenesis pathways, and DEGs in the cells of Group 3 were mainly enriched in the ovarian steroidogenesis pathway. GO analysis showed that compared to cells of Group 2, DEGs in Group 3 were primarily enriched in the SRP-dependent co-translational protein targeting pathway and co-translational protein targeting to the membrane. The results were formulated with a minimal difference in the histological evaluation of cells after quick and slow thawed tissue. Cryopreservation of ovarian tissue by the described method does not decrease follicle production but downregulates the ovarian steroidogenesis pathway, reducing estrogen and progesterone secretion. The quick thawing of ovarian tissue increases the proliferation and apoptosis pathways of cells.

In Vitro and In Vivo Evaluation of the Fertilization Capacity of Frozen/Thawed Rooster Spermatozoa Supplemented with Different Concentrations of Trehalose

The objective of this study was to evaluate the impact of the supplementation of varying concentrations of the impermeable disaccharide trehalose on the in vitro and in vivo fertilization capacity of cryopreserved rooster spermatozoa in the original Czech Golden Spotted Hen breed. The control trehalose concentration was 0 mM, while TRE50 (50 mM), TRE100 (100 mM), and TRE200 (200 mM) were used as experimental trehalose concentrations. The kinematic and functional parameters of frozen/thawed spermatozoa were evaluated in vitro using mobile computer-assisted sperm analysis and a flow cytometer. The addition of 100 mM trehalose demonstrated the most favorable results for total (34.17%) and progressive (3.57%) motility after thawing. A statistically significant difference was found for these kinetic parameters compared to the other monitored concentrations. This experimental group was also found to have a significantly higher percentage of spermatozoa without plasma membrane or acrosome damage (33.37%) compared to the TRE50 group (30.74%; p < 0.05) and the TRE200 group (29.05%; p < 0.05). In vivo, artificial insemination was performed to verify fertilization ability. Hens (n = 40) were artificially inseminated twice (10 hens/treatment) with a 3-day interval between inseminations. In conclusion, the addition of 100 mM trehalose significantly improved total and progressive motility after thawing and preserved plasma membrane and acrosome integrity (p < 0.05). The fertilization rate of eggs fertilized with semen frozen with the addition of 100 mM trehalose was not significantly different from the other concentrations tested or the control group but was numerically higher (23.21% vs. 15.20% of fertilized eggs in this group).

Supercritical density fluctuations and structural heterogeneity in supercooled water-glycerol microdroplets

Recent experiments and theoretical studies strongly indicate that water exhibits a liquid-liquid phase transition (LLPT) in the supercooled domain. An open question is how the LLPT of water can affect the properties of aqueous solutions. Here, we study the structural and thermodynamic properties of supercooled glycerol-water microdroplets at dilute conditions (χg = 3.2% glycerol mole fraction). The combination of rapid evaporative cooling with femtosecond X-ray scattering allows us to outrun crystallization and gain access to the deeply supercooled regime down to T = 229.3 K. We find that the density fluctuations of the glycerol-water solution or, equivalently, its isothermal compressibility, κT, increases upon cooling. This is confirmed by molecular dynamics simulations, which indicate that the presence of glycerol shifts the temperature of maximum κT from T = 230 K in pure water down to T = 223 K in the solution. Our findings elucidate the interplay between the complex behavior of water, including its LLPT, and the properties of aqueous solutions at low temperatures, which can have practical consequences in cryogenic biological applications and cryopreservation techniques.

Egg Cryopreservation for Social Reasons-A Literature Review

This paper provides an overview of the social reasons that lead women to consider egg cryopreservation, as well as the attitudes and knowledge of women towards this procedure. Methods: For the creation of this article, a literature review was carried out both in the existing medical literature and in search engines. The key points are as follows: (1) The main reasons women choose to delay childbearing are the lack of a suitable male partner, education and career advancement, and financial instability. Women feel societal and family pressure to have children, even though they may not feel ready. (2) Women's attitudes towards egg cryopreservation vary. While some are open to the idea, many are opposed to it, especially when it is used for non-medical reasons. There are concerns about the success rates, health risks, and ethical implications of the procedure. (3) The legal and regulatory framework around egg cryopreservation differs across countries. Some countries allow it only for medical reasons, while others have more permissive policies. The issue of who should bear the financial cost of the procedure is also debated. (4) There is a need to better educate women, as well as healthcare providers, about fertility decline and the options available for preserving fertility, including egg cryopreservation.

Manila duck (Cairina moschata) frozen semen quality in lactated ringer's egg yolk-astaxanthin with different concentrations of DMSO

This study was conducted to evaluate manila duck's (Cairina moschata) frozen semen quality after cryopreservation in lactated ringer's egg yolk-astaxanthin (LREY-A) with 5 different concentrations of dimethyl sulfoxide (DMSO). Methodology: Semen was collected from 3 manila ducks (Cairina moschata) using the cloaca massage technique twice a week. Fresh semen was evaluated macro and microscopically then polled and divided into 5 tubes of treatments. Each tube was diluted in DMSO4, DMSO6, DMSO8, DMSO10, and DMSO12. The semen of each treatment was loaded into a 0.25 mL straw and equilibrated at 5 °C for 2 h. Freeze above nitrogen vapor and stored a container of liquid nitrogen at -196 °C, then semen thawed in a water bath at 37 °C for 30 sec. Data were analyzed using One-Way ANOVA Analysis. Results of this showed that post-equilibration sperm motility and sperm viability have differed significantly (P<0.05) for each treatment, with the highest % sperm motility DMSO8 and DMSO6, this is also shown in post-thawing sperm motility and viability which have differed significantly (P<0.05) and the highest % sperm viability were DMSO8 and DMSO6. In conclusion, Frozen semen extender formulation of DMSO8 and DMSO6 which are used in manila duck semen cryopreservation was the best to other treatments to maintain % sperm motility and % sperm viability in post-equilibration and post-thawing. The highest sperm motility recovery rate was in DMSO8. The lowest sperm live and dead abnormality was in DMSO8. It is concluded that the combination of DMSO8 was the best in maintaining the quality of manila duck frozen semen.

Vitrification alters growth differentiation factor 9 and follicle-stimulating hormone receptor expression in human cumulus-mural granulosa cells

OBJECTIVE

Ovarian tissue vitrification is widely utilized for fertility preservation in prepubertal and adolescent female patients with cancer. The current literature includes reports of successful pregnancy and live birth following autografting. However, the effects of the vitrification process on cumulus-mural granulosa cells (C-mGCs)-somatic cells in ovarian tissue crucial for oocyte maturation and early embryonic development-remain unclear. This study was conducted to explore the impact of vitrification on the cellular function of C-mGCs by quantifying the expression of growth differentiation factor 9 (GDF-9), bone morphogenetic protein 15 (BMP-15), follicle-stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), connexin 37, survivin, and caspase 3.

METHODS

Mature and immature C-mGCs were obtained from 38 women with polycystic ovary syndrome who participated in an in vitro fertilization program. The C-mGCs were then divided into two groups: fresh and vitrified. The expression levels of target genes were assessed using real-time quantitative polymerase chain reaction.

RESULTS

After vitrification, GDF-9 expression was significantly decreased among both mature and immature C-mGCs, with 0.2- and 0.1-fold changes, respectively (p<0.01). Similarly, FSHR expression in the mature and immature groups was reduced by 0.1- and 0.02-fold, respectively, following vitrification (p<0.01). The expression levels of the other genes, including BMP-15, LHR, connexin 37, survivin, and caspase 3, remained similar across the examined groups (p>0.05).

CONCLUSION

Vitrification may compromise oocyte maturation through reduced GDF-9 and FSHR expression in C-mGCs after warming.

Automation preserves product consistency and quality for the formulation, fill, and finish of T cell-based therapies

Scaling up the manufacture of cell therapies can be complex and challenging. Maintaining critical quality attributes of the cell product during its final formulation and fill-finish into multiple containers can be especially difficult and laborious. Here, we tested the automated Finia™ Fill and Finish System to efficiently scale up the formulation and fill-finish of a T cell product, and then assessed cell quality and product consistency across different sub-lots filled during this expanded process. We found that this automated system could be effectively scaled to 4 times its singular capacity in a 2-h time interval, with variation in cell number and product volume less than 12% across all containers. Analysis of the different sub-lots of the final product revealed high cell viability and consistent T cell phenotype, with a high proportion of effector memory and central memory T cells and low expression of T cell senescence and exhaustion markers. The functionality of the T cell product was compared by measuring cytokine response after restimulation, with secreted levels of effector cytokines like IFN-γ and TNF-α being similar across the different sub-lots. Collectively, these results show that automation can scale up the formulation and fill-finish of a cell manufacturing process while maintaining the phenotype and functionality of the cell product. Better understanding of how to maintain product uniformity and quality during final manufacturing is important to the further scale-up and development of successful cell therapies.

Exploring the versatility of Porphyridium sp.: A comprehensive review of cultivation, bio-product extraction, purification, and characterization techniques

Interest in red microalgae of the Porphyridium genus has surged due to their richness in phycobiliproteins, polyunsaturated fatty acids, and sulfated polysaccharides. These biomasses and their derivatives find applications across food, feed, nutraceutical, pharmaceutical, and cosmetic industries. A deeper understanding of their properties and extraction methods is essential to optimize downstream processing. This paper comprehensively reviews Porphyridium sp., focusing on cultivation techniques, bioproduct extraction, purification, and characterization. It delves into protein, lipid, and polysaccharide extraction, considering the influence of culture conditions on biomass yield. Various methods like chromatography, electrophoresis, and membrane-based techniques for cell lysis and bioproduct recovery are explored, highlighting their pros and cons. By offering diverse insights, this review aims to inspire innovative research and industry progress in red microalgae biotechnology, contributing to sustainable solutions across sectors.

Optimizing transport methods to preserve function of self-innervating muscle cells for laryngeal injection

Objectives

Recently, our laboratory has discovered a self-innervating population of muscle cells, called motor endplate-expressing cells (MEEs). The cells innately release a wide variety of neurotrophic factors into the microenvironment promoting innervation when used as an injectable treatment. Unlike other stem cells, the therapeutic potential of MEEs is dependent on the cells' ability to maintain phenotypical cell surface proteins in particular motor endplates (MEPs). The goal of this study is to identify transport conditions that preserve MEE viability and self-innervating function.

Methods

Muscle progenitor cells (MPCs) of adult Yucatan pigs were cultured and induced to generate MEEs. Effects of short-term cryopreservation methods were studied on MPC and MEE stages. A minimally supplemented medium was investigated for suspension-mediated transport, and MEEs were loaded at a constant concentration (1 × 107 cells/mL) into plastic syringes. Samples were subjected to varying temperatures (4, 22, and 37°C) and durations (6, 18, 24, and 48 h), which was followed by statistical analysis of viability. Transport conditions maintaining viability acceptable for cellular therapy were examined for apoptosis rates and expression of desired myogenic, neurotrophic, neuromuscular junction, and angiogenic genes.

Results

Cryopreservation proved detrimental to our cell population. However, a minimally supplemented medium, theoretically safe for injection, was identified. Transport temperature and duration impacted cell viability, with warmer temperatures leading to faster death rates prior to the end of the study. Transport conditions did not appear to affect apoptotic rate. Any expression change of desirable genes fell within the acceptable range.

Conclusions

Transport state, medium, duration, and temperature must be considered during the transport of injectable muscle cells as they can affect cell viability and expression of integral genes. These described factors are integral in the planning of general cell transport and may prove equally important when the cell population utilized for laryngeal injection is derived from a patient's own initial muscle biopsy.

Fuzi Polysaccharide Isolated from Aconitum Carmichaeli Protects Against Liquid Nitrogen Cryopreservation-Induced Damage in Rat Abdominal Aorta by Enhancing Autophagy

BACKGROUND

To investigate the potential protective mechanisms of aconite polysaccharide (fuzi polysaccharide [FZPS-1]) during cryopreservation, with a particular emphasis on morphological changes in autophagy in rat abdominal aorta.

METHODS

Thirty-six male standard deviation rats were divided into the control group, the cryopreserved model group, and the FZPS-1 intervention group treated with different concentrations of FZPS-1. The structural changes of the abdominal aortic wall were assessed via Masson staining, while cytolysosomes were identified using transmission electron microscope (TEM). The expression of Beclin-1, microtubule-associated protein 1A/1B-light chain 3 (LC3)-II, and P62 was detected by immunohistochemistry and western blot separately. Bcl-2 and Bax messenger RNA (mRNA) expression was measured by RT-qPCR.

RESULTS

Compared with the control group, the abdominal aortic wall in the model group was severely damaged. Contrarily, FZPS-1 10 mg/mL and 20 mg/mL groups had relatively normal structure of the blood vessel wall, higher cytolysosome counts, and increased Beclin-1 and LC3-II expression compared with the model group (all P < 0.05); P62 expression also increased in the FZPS-1 20 mg/mL group (P < 0.05). Compared with the control group, the mRNA expression of Bcl-2 in the cryopreservation model group was reduced (P < 0.05), while Bax was increased (P < 0.05). Compared with the cryopreservation model group, the mRNA expression of Bcl-2 was upregulated, while Bax was downregulated in the farnesyl pyrophosphate synthase 10 mg/L group (P < 0.05).

CONCLUSION

During liquid nitrogen cryopreservation, autophagy is inhibited in the rat abdominal aorta, and the blood vessel wall structure is damaged. FZPS-1, as a cryoprotectant, can enhance autophagy and mitigate blood vessel wall damage in the rat abdominal aorta.

A microfluidic hanging droplet as a programmable platform for mammalian egg vitrification

Egg (oocyte) vitrification is the dominant method for preserving fertility for women of reproductive age. However, the method is typically performed by hand, requiring precise (∼0.1 to 10 μL) and time-sensitive (∼1 s) liquid exchange of cryoprotectants (CPA) around eggs as well as fine handling of eggs (∼100 μm) for immersion into liquid nitrogen (LN2). Here, we developed a microfluidic platform for programmable vitrification. Our platform is based on a millimeter-sized hanging droplet inside which a given egg is suspended and subjected to liquid exchanges within seconds. After programmable exposures to CPA, the egg is extracted from the liquid-air interface of the droplet using a motorized fine-tip instrument and immersed into LN2 for vitrification. To benchmark our platform with the manual method, we vitrified over a hundred mouse eggs and found comparable percentages (∼95%) for post-vitrification survivability. In addition, our platform performs real-time microscopy of the egg thereby enabling future studies where its morphology may be linked to functional outcomes. Our study contributes to the ongoing efforts to enhance the automation of embryology techniques towards broader applications in reproductive medicine both for clinical and research purposes.

Biopsy vitrification: New tool for endometrial tissue cryopreservation for research applications

Patient-derived endometrial biopsies serve as a crucial source for molecular studies, highlighting the necessity for tissue cryopreservation methods that preserve cell viability and tissue morphology with minimal to no impact. The passive slow freezing (PSF) protocol has demonstrated efficacy for cryopreserving endometrial biopsies, allowing for the subsequent isolation of viable epithelial and stromal cells. Vitrification (VT) enables the avoidance of ice crystal formation and could therefore potentially prevent mechanical injury to tissues. In this study, PSF and VT techniques were applied to endometrial biopsies, and the effects of cryopreservation on tissue samples were evaluated using traditional histology. In addition, transmission electron microscopy (TEM), gene expression profiling analyses, the viability of endometrial cells, and the ability to form epithelial organoids were compared between PSF and VT endometrial biopsies in a subset of samples. The histology and TEM studies demonstrated relatively mild cellular and sub-cellular damage in both cryopreservation protocols which did not affect tissue functionality and the formation of the organoids. Additionally, the cryopreservation methodology did not affect the gene expression profile of the 68 endometrial-receptivity associated genes studied. In conclusion, our findings indicate that although current cryopreservation methodologies need further improvements, they still allow us to achieve acceptable cell viability and functionality, showing promising potential for facilitating the utilization of cryopreserved endometrial tissue samples for research purposes.

Cryopreservation of Neuroectoderm on a Pillar Plate and In Situ Differentiation into Human Brain Organoids

Cryopreservation in cryovials extends cell storage at low temperatures, and advances in organoid cryopreservation improve reproducibility and reduce generation time. However, cryopreserving human organoids presents challenges due to the limited diffusion of cryoprotective agents (CPAs) into the organoid core and the potential toxicity of these agents. To overcome these obstacles, we developed a cryopreservation technique using a pillar plate platform. To demonstrate cryopreservation application to human brain organoids (HBOs), early stage HBOs were produced by differentiating induced pluripotent stem cells (iPSCs) into neuroectoderm (NE) in an ultralow attachment (ULA) 384-well plate. The NE was transferred and encapsulated in Matrigel on the pillar plate. The NE on the pillar plate was exposed to four commercially available CPAs, including the PSC cryopreservation kit, CryoStor CS10, 3dGRO, and 10% DMSO, before being frozen overnight at -80 °C and subsequently stored in a liquid nitrogen dewar. We examined the impact of the CPA type, organoid size, and CPA exposure duration on cell viability post-thaw. Additionally, the differentiation of NE into HBOs on the pillar plate was assessed using RT-qPCR and immunofluorescence staining. The PSC cryopreservation kit proved to be the least toxic for preserving the early stage HBOs on the pillar plate. Notably, smaller HBOs showed higher cell viability postcryopreservation than larger ones. An incubation period of 80 min with the PSC kit was essential to ensure optimal CPA diffusion into HBOs with a diameter of 400-600 μm. These cryopreserved early stage HBOs successfully matured over 30 days, exhibiting gene expression patterns akin to noncryopreserved HBOs. The cryopreserved early stage HBOs on the pillar plate maintained high viability after thawing and successfully differentiated into mature HBOs. This on-chip cryopreservation method could extend to other small organoids, by integrating cryopreservation, thawing, culturing, staining, rinsing, and imaging processes within a single system, thereby preserving the 3D structure of the organoids.

Unlocking Potential: A Comprehensive Overview of Cell Culture Banks and Their Impact on Biomedical Research

Cell culture banks play a crucial role in advancing biomedical research by providing standardized, reproducible biological materials essential for various applications, from drug development to regenerative medicine. This opinion article presents a comprehensive overview of cell culture banks, exploring their establishment, maintenance, and characterization processes. The significance of ethical considerations and regulatory frameworks governing the use of cell lines is discussed, emphasizing the importance of quality control and validation in ensuring the integrity of research outcomes. Additionally, the diverse types of cell culture banks-primary cells, immortalized cell lines, and stem cells-and their specific contributions to different fields such as cancer research, virology, and tissue engineering are examined. The impact of technological advancements on cell banking practices is also highlighted, including automation and biobanking software that enhance efficiency and data management. Furthermore, challenges faced by researchers in accessing high-quality cell lines are addressed, along with proposed strategies for improving collaboration between academic institutions and commercial entities. By unlocking the potential of cell culture banks through these discussions, this article aims to underline their indispensable role in driving innovation within biomedical research and fostering future discoveries that could lead to significant therapeutic breakthroughs.

Optimizing cryopreservation strategies for scalable cell therapies: A comprehensive review with insights from iPSC-derived therapies

Off-the-shelf cell therapies hold significant curative potential for conditions, such as Parkinson's disease and heart failure. However, these therapies face unique cryopreservation challenges, especially when novel routes of administration, such as intracerebral or epicardial injection, require cryopreservation media that are safe for direct post-thaw administration. Current practices often involve post-thaw washing to remove dimethyl sulfoxide (Me2SO), a cytotoxic cryoprotective agent, which complicates the development and clinical translation of off-the-shelf therapies. To overcome these obstacles, there is a critical need to explore Me2SO-free cryopreservation methods. While such methods typically yield suboptimal post-thaw viability with conventional slow-freeze protocols, optimizing freezing profiles offers a promising strategy to enhance their performance. This comprehensive review examines the latest advancements in cryopreservation techniques across various cell therapy platforms, with a specific case study of iPSC-derived therapies used to illustrate the scalability challenges. By identifying key thermodynamic and biochemical phenomena that occur during freezing, this review aims to identify cell-type independent approaches to improve the efficiency and efficacy of cryopreservation strategies, thereby supporting the widespread adoption and clinical success of off-the-shelf cell therapies.

Structural investigation, computational analysis, and theoretical cryoprotectant approach of antifreeze protein type IV mutants

Antifreeze proteins (AFPs) have unique features to sustain life in sub-zero environments due to ice recrystallization inhibition (IRI) and thermal hysteresis (TH). AFPs are in demand as agents in cryopreservation, but some antifreeze proteins have low levels of activity. This research aims to improve the cryopreservation activity of an AFPIV. In this in silico study, the helical peptide afp1m from an Antarctic yeast AFP was modeled into a sculpin AFPIV, to replace each of its four α-helices in turn, using various computational tools. Additionally, a new linker between the first two helices of AFPIV was designed, based on a flounder AFPI, to boost the ice interaction activity of the mutants. Bioinformatics tools such as ExPASy Prot-Param, Pep-Wheel, SOPMA, GOR IV, Swiss-Model, Phyre2, MODFOLD, MolPropity, and ProQ were used to validate and analyze the structural and functional properties of the model proteins. Furthermore, to evaluate the AFP/ice interaction, molecular dynamics (MD) simulations were executed for 20, 100, and 500 ns at various temperatures using GROMACS software. The primary, secondary, and 3D modeling analysis showed the best model for a redesigned antifreeze protein (AFP1mb, with afp1m in place of the fourth AFPIV helix) with a QMEAN (Swiss-Model) Z score value of 0.36, a confidence of 99.5%, a coverage score of 22%, and a p value of 0.01. The results of the MD simulations illustrated that AFP1mb had more rigidity and better ice interactions as a potential cryoprotectant than the other models; it also displayed enhanced activity in limiting ice growth at different temperatures.

Orthobiologic Products: Preservation Options for Orthopedic Research and Clinical Applications

The biological products used in orthopedics include musculoskeletal allografts-such as bones, tendons, ligaments, and cartilage-as well as biological therapies. Musculoskeletal allografts support the body's healing process by utilizing preserved and sterilized donor tissue. These allografts are becoming increasingly common in surgical practice, allowing patients to avoid more invasive procedures and the risks associated with donor site morbidity. Bone grafting is one of the most frequently used procedures in orthopedics and traumatology. Biologic approaches aim to improve clinical outcomes by enhancing the body's natural healing capacity and reducing inflammation. They serve as an alternative to surgical interventions. While preliminary results from animal studies and small-scale clinical trials have been promising, the field of biologics still lacks robust clinical evidence supporting their efficacy. Biological therapies include PRP (platelet-rich plasma), mesenchymal stem cells (MSCs)/stromal cells/progenitor cells, bone marrow stem/stromal cells (BMSCs), adipose stem/stromal cells/progenitor cells (ASCs), cord blood (CB), and extracellular vesicles (EVs), including exosomes. The proper preservation and storage of these cellular therapies are essential for future use. Preservation techniques include cryopreservation, vitrification, lyophilization, and the use of cryoprotective agents (CPAs). The most commonly used CPA is DMSO (dimethyl sulfoxide). The highest success rates and post-thaw viability have been achieved by preserving PRP with a rate-controlled freezer using 6% DMSO and storing other cellular treatments using a rate-controlled freezer with 5% or 10% DMSO as the CPA. Extracellular vesicles (EVs) have shown the best results when lyophilized with 50 mM or 4% trehalose to prevent aggregation and stored at room temperature.