When it comes to producing human mesenchymal stem cells (MSCs) derived from cord blood, some media perform significantly better than others, affecting process robustness as well as batch costs.
In a recent paper, a team led by Xiao Liang, senior author, and Wanglong Chu, first author, both of Shenzhen Beike Biotechnology, analyzed five basal and serum-free/xeno-free media in terms of their ability to support cell proliferation, viability, and MSC marker expression. The right formulation, they report, can increase doubling rates, reduce passage times, and prevent potency loss.
Maintaining MSC identity during expansion—another factor affected by media choice—enhances consistency among production lots and, therefore, is important in the regulatory pathway. As they point out, anchoring scaleup to a well-characterized medium helps biomanufacturers justify comparability studies and meet quality-by-design principles.
Serum-free media bests basal
The team compared five commercial MSC culture media from major companies, ultimately focusing on three serum-free and xeno-free media.
Each of the three serum-free and xeno-free media identified in the paper needed 2% human platelet lysate (HPL) supplementation to enable surface attachment and primary isolation and, thus, cell growth. Basal media was optimized at 5% HPL.
The commercial, serum-free media exhibited significant advantages, Liang and colleagues note. Compared to basal media, the serum-free media showed significantly faster passage population doubling times (ranging from nearly 17 to nearly 20 hours, versus 23 hours for basal media), small cell diameters of 15.5 to 17.8 µm, and greater morphological uniformity—factors that are linked to greater downstream viability and cryopreservation recovery. The lymphocyte proliferation suppression rate was also greater in commercial media than in basal media.
In terms of concentrations of platelet lysate supplementations and their effects on cell growth, they report negligible differences between 5% and 10% HPL. They also identified two standouts in terms of population doubling time and cell uniformity.
To assess the translational capability of this work, the team scaled the process to 16 ten-layer cell factories. Results indicated the MSCs remained stable in multibatch production.
Liang, Chu, and colleagues note their previous, uncited work in which “population doubling time increased as the remaining expiration periods of the media decreased.” Therefore, in the current research for large-scale manufacturing processes, they ensured that the remaining expiration time remained greater than 160 days. The population doubling time remained stable, and they report an “estimated medium production cost of approximately $2,472 per 1 × 109 cells.”