Long-Term Quality Control Program Plan for Cord Blood Banks in Korea: A Pilot Study for Cryopreservation Stability

Cryopreservation: A Comprehensive Overview, Challenges, and Future Perspectives

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

Collection, cryopreservation and thawing of stem cells for children weighing less than 25 Kg with high-risk neuroblastoma: A single center results in Morocco

Introduction

An important component of the advances made in neuroblastoma treatment has been the use of peripheral blood stem cells to support high-dose chemotherapy. In this study, we report our experience on a series of small children who have undergone standard and large volume leukaphersis (LVL) procedures, provide an update on a single institution's experience with cryopreservation of autologous peripheral blood stem cells (PBSCs), using 10% dimethyl sulfoxide (DMSO) and applying post-thaw DMSO depletion and analyze a number of variables that may affect viability.

Methods

A total of 36 aphereses were performed on 29 children weighing less than 25 kg between July 2016 and October 2019 at the Ibn Sina university hospital.

Results

Seven females and twenty-two males, median bodyweight 14 kg (9 - 22). A single apheresis was sufficient to obtain at least 3 × 10⁶/kg body weight (BW) of CD34+ cells in 82.8% of the cases. The LVL was performed in 22 aphereses. A median number of 5.9 × 10⁶/kg CD34 cells were collected per apheresis. A total of 60 PBSC samples were cryopreserved and 46 samples were infused. The mean cell viability percentage decreased from 94.75 ± 1.14% before freezing to 70.84 ± 8.6% after thawing (p < 0.001). No correlation was found between post-thaw viability and storage time (r = -0.233; p = 0.234) or number of total nucleated cells (r = 0.344; p = 0.073).

Conclusion

Leukapheresis is safe and feasible in small pediatric patients if the appropriate measures are used. Cryopreservation poses numerous challenges, especially a decrease in cell viability after thawing.

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs

BACKGROUND

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns.

METHODS

A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34⁺ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34⁺ cells.

RESULTS

Maternal triglycerides (TG) showed a significant positive association with BW and CD34⁺ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34⁺ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34⁺ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively).

CONCLUSIONS

We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

Cryopreservation of Hematopoietic Stem Cells: Emerging Assays, Cryoprotectant Agents, and Technology to Improve Outcomes

Hematopoietic stem cell (HSC) therapy is widely used to treat a growing number of hematological and non-hematological diseases. Cryopreservation of HSCs allows for cells to be transported from the site of processing to the site of clinical use, creates a larger window of time in which cells can be administered to patients, and allows sufficient time for quality control and regulatory testing. Currently, HSCs and other cell therapies conform to the same cryopreservation techniques as cells used for research purposes: cells are cryopreserved in dimethyl sulfoxide (DMSO) at a slow cooling rate. As a result, HSC therapy can result in numerous adverse symptoms in patients due to the infusion of DMSO. Efforts are being made to improve the cryopreservation of HSCs for clinical use. This review discusses advances in the cryopreservation of HSCs from 2007 to the present. The preclinical development of new cryoprotectants and new technology to eliminate cryoprotectants after thawing are discussed in detail. Additional cryopreservation considerations are included, such as cooling rate, storage temperature, and cell concentration. Preclinical cell assessment and quality control are discussed, as well as clinical studies from the past decade that focus on new cryopreservation protocols to improve patient outcomes.

Quality of Cryopreserved Peripheral Blood Mononuclear Cells Recovered from the Hepatitis/AIDS Biobank

Background: Peripheral blood mononuclear cells (PBMCs) count among the most important samples in a biobank, and the quality of cryopreserved PBMCs is crucial for further research. This study evaluated the quality of PBMCs recovered from the Beijing Capital Medical University Hepatitis/AIDS Biobank after 2-11 years of cryopreservation. Materials and Methods: A total of 87 PBMC samples with different cryopreservation times (2006, 2007, 2013, and 2015) were thawed, and the cell number and cell viability were determined by acridine orange/propidium iodide staining. Then, DNA was extracted from the cryopreserved PBMCs and assessed for quantity on an ultramicrospectrophotometer. Results: The median cell viability rate was 73.58% for the 87 PBMC samples cryopreserved for 2-11 years. A rate of 80.98% was obtained for PBMCs collected in 2006, a value higher than those of other cryopreservation times (2007, 2013, and 2015). Similarly, more live and total cells were obtained in PBMCs cryopreserved since 2006 compared with other cryopreservation times (since 2007, 2013, and 2015, respectively). Nonparametric Spearman correlation analysis indicated positive associations of cell viability with live (r = 0.578, p < 0.0001) and total (r = 0.338, p = 0.0003) cell numbers. Meanwhile, DNA amounts increased with total cell number. Statistical analysis showed that 3.69 μg DNA was obtained from ∼1 × 10⁶ cells. Conclusion: Cryopreservation time (2-11 years) has negligible effects on the quality of PBMCs. Meanwhile, the cell number is positively correlated with cell viability.