Freeze-dried and GMP-compliant pharmaceuticals containing exosomes for acellular mesenchymal stromal cell immunomodulant therapy

Aim: To validate the use of ultrafiltration (UF) as an alternative applicable industrial method to replace ultracentrifugation (UC) in the purification of mesenchymal stromal cell (MSC)-secretome. Materials & methods: Pharmaceutical formulations containing secretome and/or extracellular vesicles were extracted from adipose-MSCs and bone marrow-MSCs by combining UF or UC with lyophilization. Results & conclusion: UF led to higher protein, lipid, cytokine and exosomes yields compared with UC. The isolation procedure and cell source influenced immunomodulatory activity, which was in vitro evaluated by inhibition of phytohemagglutinin-activated peripheral blood mononuclear cell proliferation, and by modulation of IL-10, IFN-gamma and IL-6. A secretome dosage was identified to obtain the same immunomodulatory activity of MSCs, paving the way for cell-free therapy.