Human Serum Albumin Preserves Delivered Dose and Suspension Stability During Simulated Clinical Infusion of Mesenchymal Stromal Cells.

INTRODUCTION

Final formulation and infusion may alter the cell therapy dose delivered to the patient. We assessed whether human serum albumin (HSA) improves delivery and short-term stability of clinical-grade adipose tissue-derived mesenchymal stromal cells during simulated clinical infusion.

METHODS

Thawed cells were diluted in sodium chloride, lactated Ringer's solution, or Plasmalyte, with or without HSA, and passed through a standardized syringe-pump-catheter setup. Samples collected before infusion, immediately after infusion, and during room-temperature hold were assessed for cell concentration, viability, recovery, debris, aggregates, image-based morphology, and post-culture expansion.

RESULTS

HSA increased delivered total-cell concentration (3.05×10^6 vs 2.61×10^6 cells/mL, p < 0.001), viable-cell concentration (2.78×10^6 vs 2.27×10^6 cells/mL, p < 0.001), and viable recovery (99.8% vs 85.1%, p < 0.001). During post-infusion hold, HSA-free samples showed progressive loss of viable cells and viability, whereas HSA-containing samples remained comparatively stable. Overnight viable-cell concentration was 2.68×10^6 cells/mL with HSA versus 1.16×10^6 cells/mL without HSA, and viability was 87.8% versus 50.5%, respectively. Image-based morphology showed sustained single-cell predominance, higher single-cell counts with HSA, and a lower overnight debris-to-single-cell ratio without increased aggregate burden.

CONCLUSIONS

HSA supplementation preserves delivered cell concentration, viable-cell recovery, and short-term suspension stability during simulated clinical infusion of mesenchymal stromal cells. Final formulation is therefore a practical determinant of the cell suspension delivered to the patient.