Stem cell injections deliver benefits on OA-related structural outcomes

Intra-articular mesenchymal stem cell (MSC) injections on articular cartilage and subchondral bone result in improved osteoarthritis (OA)-related structural outcomes, according to a systematic review of early-phase clinical trials.

The investigators searched Ovid Medline and Embase from inception to April 2020 using MeSH terms and keywords. Independent reviewers extracted data and evaluated methodological quality. Qualitative evidence synthesis was carried out due to the heterogeneity of interventions and outcome measures.

Thirteen randomized controlled trials (phase I or II) were identified, of which 10 included OA populations and three involved populations at risk of OA. Risk of bias was high in one study, moderate in three, and low in nine.

Seven studies used allogeneic MSCs (four bone marrow, one umbilical cord, one placenta, and one adipose tissue), while six used autologous MSCs (three adipose tissue, two bone marrow, and one peripheral blood).

Ten of the 11 studies examining cartilage outcomes found MSCs to be advantageous on cartilage volume, morphology, quality, regeneration, and repair, as assessed by magnetic resonance imaging, arthroscopy, or histology. The evidence for subchondral bone was consistent in all three studies on populations at risk of OA, demonstrating beneficial effects.

In addition, 16 unpublished, eligible trials were identified through trial registries search, including eight with actual or estimated completion dates before 2016.

“Due to the heterogeneity of MSCs, modest sample sizes, methodological limitations, and potential for publication bias, further work is needed before this therapy is recommended in the management of OA,” the investigators said.