No abstract

The expanding complexity of biologics banked for therapeutic applications necessitates the development of improved preservation technologies for support of the emerging fields of reparative and regenerative medicine. Currently, a number of media or "solutions" are utilized for the preservation of biologics. Given the diversity of cell systems utilized in the regenerative medicine arena, we hypothesized that the development of unique (individualized) preservation solutions designed to meet the distinct molecular biological requirements of individual systems would provide for enhanced and extended preservation. To evaluate this hypothesis, coronary artery smooth muscle cells (CASMCs), coronary artery endothelial cells (CAECs), hepatic cells (C3A), and skeletal muscle cells (SKMCs) were hypothermically preserved for 2 to 7 days at 4 degrees C in either cell culture medium, University of Wisconsin Solution (UW or ViaSpan), or HypoThermosol (HTS) variants. Cells were then assayed for viability, using the alamarBlue assay as well as calcein-AM, subsequent to their return to normothermic (37 degrees C) temperatures for up to 5 days. CASMC viability was best maintained when preserved in HTS plus Trolox/EDTA, CAEC viability was highest when preserved in HTS plus Trolox, SKMCs stored in HTS plus Trolox/RGD demonstrated enhanced viability, and C3A cells were best preserved in HTS plus FK041. The data suggest that solution compositions that address the differences in cell death mechanisms limiting preservation efficacy can result in targeted improvement matched to specific cell types. These observations support the custom solution hypothesis of cell and tissue preservation.

Background Peripheral blood stem cells (PBSC) have become the preferred stem cell source for autologous hematopoietic transplantation. A critical aspect of this treatment modality is cryopreservation of the stem cell products, which permits temporal separation of the PBSC mobilization/collection phase from the subsequent high-dose therapy. While controlled rate freezing and liquid nitrogen storage have become “routine” practice in many cell processing facilities, there is clearly room for improvement, as current cryopreservation media formulations still result in significant loss and damage to the stem/progenitor cell populations essential for engraftment, and can also expose the patients to relatively undefined serum components and larger volumes of DMSO that can contribute to the morbidity and mortality of the transplant therapy. Methods This study compared cryopreservation of PBSC in a novel intracellular-like, fully defined, serum- and protein-free preservation solution, CryoStor™ (BioLife Solutions, Inc.), with a standard formulation used by the Fred Hutchinson Cancer Research Center (FHCRC). Briefly, human PBSC apheresis specimens were collected and 5 × 107 cells/1 ml sample vial were prepared for cryopreservation in the following solutions: 1) FHCRC standard – Normosol-R, 5% HSA, 10% DMSO, and 2) CryoStor™ CS10 (final diluted conc. of 5% DMSO). A standard controlled-rate freezing program was employed, and frozen vials were stored in the vapor phase of a liquid nitrogen freezer for a minimum of one week. Vials were then thawed and evaluated for TNC, Viability, CD34, and granulocytes by flow cytometry, along with colony-forming activity in methylcellulose. Results The PBSC samples frozen in CryoStor™ CS10 yielded significantly improved post-thaw recoveries for total viable CD34+, CFU, and viable granulocytes. Specifically, relative to the FHCRC standard formulation, cryopreservation with CS10 resulted in an average 1.8 fold increased recovery of viable CD34+ cells (P = 0.005), a 1.5 fold increase in CFU-GM numbers (P = 0.030), and a 2.3 fold increase in granulocyte recovery (P = 0.045). Discussion This study indicates that use of CryoStor™ for cryopreservation can yield significantly improved recovery and in vitro functionality of the stem/progenitor cells in PBSC products. In addition, it is important to note that these improved recoveries were obtained while also not introducing any extra serum or serum-derived proteins, and reducing the final concentration/volume of DMSO by half. Further in vitro and in vivo studies are clearly necessary, however these findings imply use of CryoStor™ for cryopreservation might ultimately result in improved engraftment for those patients with lower content of CD34+ cells in their PBSC collections, along with reducing the requirement for additional apheresis collections, and decreasing the risk of adverse infusion reactions associated with higher exposure to DMSO.

No abstract

This study has important implications in determining the best cryoprotectant solution for specific clinical applications in allogeneic immunotherapy.

No abstract

Cellular therapies are cell and tissue products sourced from biological materials that are employed as 'living drugs. ' Such 'living drugs' require specialized biological support, namely biopreservation, to maintain optimal recovery, viability and return to function post-preservation. To achieve successful biopreservation, optimization of a multitude of parameters, including cooling/thawing rates based on the biophysics of specific cell types, the temperature of storage and transportation, as well as biopreservation media are of paramount importance. In particular, the choice of biopreservation media is pivotal for clearing regulatory hurdles and facilitating commercialization. Traditional extracellular-like (isotonic), home-brew cocktails (which may contain serum) may not be compatible with a Good Manufacturing Practices (GMP) clinical manufacturing process. This article will address the challenges associated with maintaining the viable recovery and functionality of 'living drugs' , discuss the benefits and consequences of low-temperature biopreservation, outline Biopreservation Best Practices, and propose considerations for incorporating Biopreservation Best Practices into a GMP cell therapy product. Integration of Biopreservation Best Practices, beginning with the selection of optimized media, ensures that cells remain viable and functional throughout the cell product lifecycle, thereby optimizing manufacturing and clinical outcomes.

Slow and fast addition of cryopreservation solutions result in mean temperature changes of approximately 3.3 to 4.45°C. Postthaw recoveries with CryoStor were equivalent to or slightly better than with the in-house cryopreservation solution. CryoStor also provides several advantages including reduced processing time, formulation consistency, and reduced DMSO in the frozen product (≤ 5%).