Therapeutic Use of Mesenchymal Stromal Cells: The Need for Inclusive Characterization Guidelines to Accommodate All Tissue Sources and Species

Abstract

Following their discovery over 50 years ago, mesenchymal stromal cells (MSCs) have become one of the most studied cellular therapeutic products by both academia and industry due to their regenerative potential and immunomodulatory properties. The promise of MSCs as a therapeutic modality has been demonstrated by preclinical data yet has not translated to consistent, successful clinical trial results in humans. Despite the disparities across the field, MSC shareholders are unified under one common goal-to use MSCs as a therapeutic modality to improve the quality of life for those suffering from a malady in which the standard of care is suboptimal or no longer effective. Currently, there is no Food and Drug Administration (FDA)-approved MSC therapy on the market in the United States although several MSC products have been granted regulatory approval in other countries. In this review, we intend to identify hurdles that are impeding therapeutic progress and discuss strategies that may aid in accomplishing this universal goal of widespread therapeutic use.

Keywords: MSC; biotherapeutic development; clinical translation challenge; commercialization; metrology and characterization.

Figure 1

Canine Expression of MSC Markers in the Literature. Positive expression is defined here as >50% surface marker expression, moderate is defined as ≥5%— <50%, and anything <5% is considered to be a negative result. Data derived from Wright et al. (2020).

Figure 2

Porter's five forces analysis of competitive environment within MSC clinical use.