Optimizing the transport and storage conditions of current Good Manufacturing Practice - grade human umbilical cord mesenchymal stromal cells for transplantation (HUC-HEART Trial)

Background: The HUC-HEART Trial is a clinical study of intramyocardial delivery of current Good Manufacturing Practice (cGMP)-grade human umbilical cord multipotent stromal cells (HUC-MSCs) in ischemic cardiomyopathy where 2 x 10(7) cells are administered to peri-infarcted myocardium. Prior to the onset of the trial, we aimed to optimize the transport/storage conditions for obtaining the highest cell viability and proliferation rate of cells to be transplanted. Methods: Cells were tested after being transported in phosphate-buffered saline (PBS) or Ringer's lactate-based (RL) transport media supplemented with human serum albumin (HSA) and/or hydroxyethyl starch (HES) at two temperatures (2-10 degrees C or 22-24 degrees C). Results: The effects of transport conditions on cell viability following 6 h were found highest (93.4 +/- 1.5) in RL-based media at 2-10 degrees C. Karyotypes were found normal upon transportation in any of the formulations and temperatures. However, the highest proliferation rate was noted (3.1-fold increase) in RL (1% HSA) media at 2-10 degrees C over 6 days in culture. From that point, RL (1% HSA) media at 2-10 degrees C was used for further experiments. The maximum cell storage time was detected around 24 h at 2-10 degrees C. Extended storage periods resulted in a decrease in cell viability but not in MSC marker expression. An increase in actin quantity was detected in hypoxia (5% O-2) groups in early culture days; no difference was noted between hypoxic versus normoxic (21% O2) conditions in later days. Discussion: The overall results suggest that non-commercial, simple media formulations with extended storage intervals at 2-10 degrees C temperatures are capable of retaining the characteristics of clinical-grade HUC-MSCs. The above findings led us to use RL (1% HSA) media at 2-10 degrees C for transport and storage in the HUC-HEART Trial; 23 patients received HUC-MSCs by August 2018; no adverse effects were noted related to cell processing and transplantation.