Closed system isolation and scalable expansion of human placental mesenchymal stem cells

Abstract

Mesenchymal stem cells (MSC) are emerging as a leading cellular therapy for a number of diseases. However, for such treatments to become available as a routine therapeutic option, efficient and cost-effective means for industrial manufacture of MSC are required. At present, clinical grade MSC are manufactured through a process of manual cell culture in specialized cGMP facilities. This process is open, extremely labor intensive, costly, and impractical for anything more than a small number of patients. While it has been shown that MSC can be cultivated in stirred bioreactor systems using microcarriers, providing a route to process scale-up, the degree of numerical expansion achieved has generally been limited. Furthermore, little attention has been given to the issue of primary cell isolation from complex tissues such as placenta. In this article we describe the initial development of a closed process for bulk isolation of MSC from human placenta, and subsequent cultivation on microcarriers in scalable single-use bioreactor systems. Based on our initial data, we estimate that a single placenta may be sufficient to produce over 7,000 doses of therapeutic MSC using a large-scale process.

Isolation and Expansion of Mesenchymal Stem/Stromal Cells Derived from Human Placenta Tissue

“…Induction medium was exchanged twice per week over the culture period. Following 14 days of induction, cultures were characterized for either bone-like matrix (osteogenesis) or lipid vacuoles (adipogenesis) as per our previous publication In previous publications, we have characterized the differentiation potential of placental-derived MSC more extensively 4,5 . Placental-derived MSC osteogenesis is similar to bone marrow-derived MSC, while adipogenesis is generally less efficient in placental-derived MSC 5 .…”

“…MSC derived from placenta have long-term proliferation 5 and immunomodulatory capacity 6 , superior to bone marrow-derived MSC. In a previous study, we demonstrated that a single term placenta contained sufficient MSC for the manufacture of up to 7,000 clinical doses 4 . These characteristics make placenta an ideal source tissue for the manufacture of allogeneic MSC.…”

“…In many of these applications, allogeneic MSC may be as effective as autologous MSC 3 . The use of allogeneic MSC has the economic advantage of being compatible with the large-scale manufacture of multiple cell doses from a single source tissue 4 to treat many patients.…”

“…Historically, pre-clinical and clinical studies have utilized MSC-derived from the bone marrow 4 . Bone marrow is generally collected from the iliac crest of a volunteer donor.…”

“…Cell potency decreases with passage number 3 , creating a paradox where the theoretical number of cells required for clinical efficacy is increased the more the cell population is expanded. In contrast to bone marrow aspirates, term placenta is a physically large starting tissue (typically 500-750 g 4 ), which can be harvested aseptically during cesarean section with no risk to the donor. MSC derived from placenta have long-term proliferation 5 and immunomodulatory capacity 6 , superior to bone marrow-derived MSC.…”