Post-release handling and administration preserve the quality of adipose-derived mesenchymal stromal cell products across multiple delivery systems

Introduction Mesenchymal stromal cells (MSCs) are used clinically across regenerative and inflammatory indications, yet post-release steps including thawing, reconstitution, short room-temperature (RT) holds, and administration remain variably standardized and poorly documented. Post-release handling often occurs outside GMP oversight despite its potential impact on cell quality. Methods This study evaluated the impact of clinically relevant post-release handling conditions on adipose-derived MSCs (AD-MSCs) using in vitro models simulating common administration routes. AD-MSCs from three healthy donors were tested under four conditions: (1) baseline after reconstitution, (2) immediate administration, (3) 4-h RT storage, and (4) 4-h RT storage followed by administration. Five administration routes were simulated and evaluated independently using clinically relevant delivery systems. Viability, morphology, aggregation, debris, and immunophenotype were assessed using NucleoCounter analysis, microscopy, and flow cytometry. Results Cell counts remained stable across all conditions and administration routes. Viability exceeded the predefined acceptance criterion (≥80%) throughout, with the only significant change observed after 4-h storage in the intravenous administration system (mean viability 93.8% ± 1.0% at baseline versus 90.6% ± 2.7% after 4 h storage). Debris and aggregation remained below 10% across all conditions, indicating minimal fragmentation and clumping risk. Immunophenotype was preserved following storage (CD73/CD90/CD105 ≥90%; negative markers ≤1%). Morphology remained spindle-shaped, although reduced plastic adherence was observed after 4-h storage and passage through the intradiscal administration system. Needle-based administration across a clinically relevant range (21G-27G) had no adverse impact on viability, morphology, or aggregation. Discussion Post-release handling and administration maintained AD-MSC quality within predefined acceptance criteria across all evaluated delivery systems. Although small route-dependent changes were observed, none exceeded established quality thresholds. These findings support the robustness of the evaluated post-release handling procedures and provide a pragmatic quality-control framework for assessing maintenance of AD-MSC quality attributes during administration.