Combination of trehalose and inulin efficacy as lyoprotectant for the preservation of human monocytic cell line

Traditional cell cryopreservation is expensive and logistically complex, and it necessitates a constant cold chain [44,57]. Lyophilization presents an alluring substitute, so long as the right lyoprotectants are applied to preserve cell integrity [23,40,44,52]. This study examined whether the human THP-1 mononuclear cell line's viability and function are maintained during the lyophilization process when trehalose and inulin are combined as a lyoprotectant. Cell survival, membrane integrity, metabolic activity, and functional responsiveness (differentiation and cytokine secretion) were assessed after THP-1 cells were processed in various lyophilization conditions (trehalose alone versus trehalose in combination with inulin). The reference cells were cryopreserved cells. Following rehydration, the vitality of cells lyophilized in a mixture containing trehalose and inulin was comparable to that of cryopreserved cells. After a recovery period in culture, the cell membranes regained their integrity, despite being temporarily permeable right after rehydration. Additionally, the inclusion of inulin helped to reduce the residual moisture content and increase the stability of the lyophilizates, while also preserving metabolic activities and the ability to differentiate (including IL-1β release after stimulus). Trehalose and inulin work well together as a lyoprotectant, lowering the stress that THP-1 cells experience during the lyophilization process. Therefore, this approach may be a practical and affordable substitute for traditional cryopreservation, maintaining the cells' stability and activity even after extended storage.