Umbilical cord derived mesenchymal stromal cells in microcarrier based industrial scale culture sustain the immune regulatory functions

Superior migration ability of umbilical cord-derived mesenchymal stromal cells (MSCs) toward activated lymphocytes in comparison with those of bone marrow and adipose-derived MSCs

Introduction: Mesenchymal stromal cells (MSCs) are activated upon inflammation and/or tissue damage and migrate to suppress inflammation and repair tissues. Migration is the first important step for MSCs to become functional; however, the migration potency of umbilical cord-derived MSCs (UC-MSCs) remains poorly understood. Thus, we aimed to assess the migration potency of UC-MSCs in comparison with those of bone marrow-derived MSCs (BM-MSCs) and adipose tissue-derived MSCs (AD-MSCs) and investigate the influence of chemotactic factors on the migration of these cells. Methods: We compared the migration potencies of UC-, BM-, and AD-MSCs toward allogeneic stimulated mononuclear cells (MNCs) in mixed lymphocyte reaction (MLR). The number of MSCs in the upper chamber that migrated toward the MLR in the lower chamber was counted using transwell migration assay. Results and discussion: UC-MSCs showed significantly faster and higher proliferation potencies and higher migration potency toward unstimulated MNCs and MLR than BM- and AD-MSCs, although the migration potencies of the three types of MSCs were comparable when cultured in the presence of fetal bovine serum. The amounts of CCL2, CCL7, and CXCL2 in the supernatants were significantly higher in UC-MSCs co-cultured with MLR than in MLR alone and in BM- and AD-MSCs co-cultured with MLR, although they did not induce the autologous migration of UC-MSCs. The amount of CCL8 was higher in BM- and AD-MSCs than in UC-MSCs, and the amount of IP-10 was higher in AD-MSCs co-cultured with MLR than in UC- and BM-MSCs. The migration of UC-MSCs toward the MLR was partially attenuated by platelet-derived growth factor, insulin-like growth factor 1, and matrix metalloproteinase inhibitors in a dose-dependent manner. Conclusion: UC-MSCs showed faster proliferation and higher migration potency toward activated or non-activated lymphocytes than BM- and AD-MSCs. The functional chemotactic factors may vary among MSCs derived from different tissue sources, although the roles of specific chemokines in the different sources of MSCs remain to be resolved.

Mapping the microcarrier design pathway to modernise clinical mesenchymal stromal cell expansion

Microcarrier expansion systems show exciting potential to revolutionise mesenchymal stromal cell (MSC)-based clinical therapies by providing an opportunity for economical large-scale expansion of donor- and patient-derived cells. The poor reproducibility and efficiency of cell expansion on commercial polystyrene microcarriers have driven the development of novel microcarriers with tuneable physical, mechanical, and cell-instructive properties. These new microcarriers show innovation toward improving cell expansion outcomes, although their limited biological characterisation and compatibility with dynamic culture systems suggest the need to realign the microcarrier design pathway. Clear headway has been made toward developing infrastructure necessary for scaling up these technologies; however, key challenges remain in characterising the wholistic effects of microcarrier properties on the biological fate and function of expanded MSCs.

A large-scale production of mesenchymal stem cells and their exosomes for an efficient treatment against lung inflammation

Mesenchymal stem cells (MSCs) and their produced exosomes have demonstrated inherent capabilities of inflammation-guided targeting and inflammatory modulation, inspiring their potential applications as biologic agents for inflammatory treatments. However, the clinical applications of stem cell therapies are currently restricted by several challenges, and one of them is the mass production of stem cells to satisfy the therapeutic demands in the clinical bench. Herein, a production of human amnion-derived MSCs (hMSCs) at a scale of over 1 × 109 cells per batch was reported using a three-dimensional (3D) culture technology based on microcarriers coupled with a spinner bioreactor system. The present study revealed that this large-scale production technology improved the inflammation-guided migration and the inflammatory suppression of hMSCs, without altering their major properties as stem cells. Moreover, these large-scale produced hMSCs showed an efficient treatment against the lipopolysaccharide (LPS)-induced lung inflammation in mice models. Notably, exosomes collected from these large-scale produced hMSCs were observed to inherit the efficient inflammatory suppression capability of hMSCs. The present study showed that 3D culture technology using microcarriers coupled with a spinner bioreactor system can be a promising strategy for the large-scale expansion of hMSCs with improved anti-inflammation capability, as well as their secreted exosomes.

Evaluation of Polymeric Particles for Modular Tissue Cultures in Developmental Engineering

Developmental engineering (DE) aims to culture mammalian cells on corresponding modular scaffolds (scale: micron to millimeter), then assemble these into functional tissues imitating natural developmental biology processes. This research intended to investigate the influences of polymeric particles on modular tissue cultures. When poly(methyl methacrylate) (PMMA), poly(lactic acid) (PLA) and polystyrene (PS) particles (diameter: 5-100 µm) were fabricated and submerged in culture medium in tissue culture plastics (TCPs) for modular tissue cultures, the majority of adjacent PMMA, some PLA but no PS particles aggregated. Human dermal fibroblasts (HDFs) could be directly seeded onto large (diameter: 30-100 µm) PMMA particles, but not small (diameter: 5-20 µm) PMMA, nor all the PLA and PS particles. During tissue cultures, HDFs migrated from the TCPs surfaces onto all the particles, while the clustered PMMA or PLA particles were colonized by HDFs into modular tissues with varying sizes. Further comparisons revealed that HDFs utilized the same cell bridging and stacking strategies to colonize single or clustered polymeric particles, and the finely controlled open pores, corners and gaps on 3D-printed PLA discs. These observed cell-scaffold interactions, which were then used to evaluate the adaptation of microcarrier-based cell expansion technologies for modular tissue manufacturing in DE.

Immunological influence of serum-free manufactured umbilical cord-derived mesenchymal stromal cells for steroid-resistant acute graft-versus-host disease

This study investigated the safety, efficacy, and immunological influence of allogeneic umbilical cord-derived mesenchymal stromal cells (IMSUT-CORD) processed in serum-free medium and cryoprotectant, for treating steroid-resistant acute graft-versus-host disease (aGVHD). In a phase I dose-escalation trial, IMSUT-CORD were infused intravenously twice weekly over two cycles with up to two additional cycles. Four patients received a dose of 1 × 10⁶ cells/kg, while three received 2 × 10⁶/kg. Of 76 total adverse events, fourteen associated or possibly associated adverse events included 2 cases of a hot flash, headache, and peripheral neuropathy, 1 each of upper abdominal pain, hypoxia, increased γ-GTP, somnolence, peripheral vascular pain at the injection site, thrombocytopenia, hypertension, and decreased fibrinogen. At 16 weeks after the initial IMSUT-CORD infusion, three patients showed complete response (CR), two partial response (PR), one mixed response, and one no response. The overall response rate was 71.4%, and the continuous CR/PR rate was 100% for over 28 days after CR/PR. NK cell count significantly increased and correlated with treatment response, whereas IL-12, IL-17, and IL-33 levels decreased, but did not correlate with treatment response. CCL2 and CCL11 levels increased during IMSUT-CORD therapy. IMSUT-CORD are usable in patients with steroid-resistant aGVHD (UMIN000032819: https://www.umin.ac.jp/ctr ).

Study on the Umbilical Cord-Mesenchymal Stem Cell Manufacturing Using Clinical-Grade Culture Medium

Mesenchymal stem/stromal cell (MSC)-based therapies have been gaining increasing attention owing to their application in various diseases and conditions. In this study, we aimed to identify the optimal condition for industrial-scale MSC manufacturing. MSCs were isolated from umbilical cord (UC) tissues by implementing the explant method (Exp) or a collagenase based-enzymatic digestion method (Col), using a good manufacturing practice-compatible serum-free medium developed in-house. Microarray analysis demonstrated that the gene expression profiles of Exp-MSCs and Col-MSCs did not significantly differ according to the method of isolation or the culture conditions used. The isolated UC-MSCs were then subjected to expansion using conventional static culture (ST) or microcarrier-based culture in stirred-tank bioreactors (MC). Metabolomic and cytokine array analyses were conducted to evaluate the biochemical status of the MSCs. However, no remarkable differences in the metabolic profile and cytokine secretome between ST-MSCs and MC-MSCs were observed. On the contrary, we observed for the first time that the hydrophobic components of ST-MSCs and MC-MSCs were different, which suggested that the cell membrane distribution of fatty acids and lipids was altered in the process of adaptation to shear stress in MC-MSCs. These results establish the flexibility of the isolation and expansion method for UC-MSCs during the manufacturing processes and provide new insights into the minor differences between expansion methods that may exert remarkable effects on MSCs. In conclusion, we demonstrated the feasibility of both Exp-MSCs and Col-MSCs and MC and ST culture methods for scale-up and scale-out of MSC production, as well as the equivalence of these cells. As for the industrialized mass production of MSCs, enzyme-based methods for isolation and cell expansion in a bioreactor were considered to be more suitable. The methods developed, which underwent comprehensive evaluation in this study, may contribute toward the provision of sufficient MSC sources and the establishment of cost-effective MSC therapies. Impact statement Our in-house-developed good manufacturing practice-grade serum-free medium could be used for both isolation (Exp and Col) and expansion (ST and MC) of umbilical cord (UC)-mesenchymal stem/stromal cells (MSCs). Characteristics of the obtained UC-MSCs were widely assessed with regard to gene expression, metabolome, and secretome. Cellular characteristics and efficacy were observed to be equivalently maintained among whichever technique was applied. In addition, our research presents the first evidence that bioreactor and microcarrier-based MSC cultures alter the fatty acid and phospholipid composition of MSCs. These results provide new insights into the differences between expansion methods that may exert remarkable effects on MSCs.

A scalable system for generation of mesenchymal stem cells derived from induced pluripotent cells employing bioreactors and degradable microcarriers

Human mesenchymal stem cells (hMSCs) are effective in treating disorders resulting from an inflammatory or heightened immune response. The hMSCs derived from induced pluripotent stem cells (ihMSCs) share the characteristics of tissue derived hMSCs but lack challenges associated with limited tissue sources and donor variation. To meet the expected future demand for ihMSCs, there is a need to develop scalable methods for their production at clinical yields while retaining immunomodulatory efficacy. Herein, we describe a platform for the scalable expansion and rapid harvest of ihMSCs with robust immunomodulatory activity using degradable gelatin methacryloyl (GelMA) microcarriers. GelMA microcarriers were rapidly and reproducibly fabricated using a custom microfluidic step emulsification device at relatively low cost. Using vertical wheel bioreactors, 8.8 to 16.3‐fold expansion of ihMSCs was achieved over 8 days. Complete recovery by 5‐minute digestion of the microcarriers with standard cell dissociation reagents resulted in >95% viability. The ihMSCs matched or exceeded immunomodulatory potential in vitro when compared with ihMSCs expanded on monolayers. This is the first description of a robust, scalable, and cost‐effective method for generation of immunomodulatory ihMSCs, representing a significant contribution to their translational potential.

Bioprocessing of Human Mesenchymal Stem Cells: From Planar Culture to Microcarrier-Based Bioreactors

Human mesenchymal stem cells (hMSCs) have demonstrated great potential to be used as therapies for many types of diseases. Due to their immunoprivileged status, allogeneic hMSCs therapies are particularly attractive options and methodologies to improve their scaling and manufacturing are needed. Microcarrier-based bioreactor systems provide higher volumetric hMSC production in automated closed systems than conventional planar cultures. However, more sophisticated bioprocesses are necessary to successfully convert from planar culture to microcarriers. This article summarizes key steps involved in the planar culture to microcarrier hMSC manufacturing scheme, from seed train, inoculation, expansion and harvest. Important bioreactor parameters, such as temperature, pH, dissolved oxygen (DO), mixing, feeding strategies and cell counting techniques, are also discussed.