Stem Cell Safety Confirmed: Insights from The Lancet

Nobel laureate Thomas C. Südhof has praised stem cell therapy as a promising treatment for diseases that traditional medicine struggles to address. However, concerns about the safety of stem cell infusions remain prevalent.

A recent comprehensive study published in The Lancet's EClinical Medicine reassures the safety and effectiveness of mesenchymal stem cell (MSC) therapy. This study reviewed randomized clinical trials (RCTs) from 2012 to 2019, building on earlier research that initially examined MSC-related adverse reactions.

Study Overview: Researchers analyzed data from multiple sources, including the Cochrane Central Register of Controlled Trials, MEDLINE, and EMBASE, focusing on potential adverse reactions such as acute reactions within 24 hours, infections, thrombosis, and long-term events like mortality and malignancy.

The study expanded on previous findings, incorporating 47 new RCTs, resulting in a total of 55 studies with 2,696 patients. These trials spanned a variety of diseases, including cardiovascular, neurological, renal, hepatic, respiratory, endocrine disorders, hematologic malignancies, and immune deficiency or inflammatory conditions. MSCs were sourced from bone marrow, umbilical cord, and adipose tissue.

Key Findings:

• Fever Risk: MSC therapy was associated with a higher risk of fever compared to control groups, though the risk has decreased since the 2012 review.
• Thrombosis: The risk of thrombosis or thromboembolism events did not significantly increase with MSC therapy.
• Mortality and Malignancy: MSC-treated patients had a lower mortality risk and no significant increase in the risk of malignancies or ectopic tissue formation compared to control groups.
• Subgroup Analysis: In patients with neurological and immune/inflammatory conditions, acute infusion toxicity risk was higher with allogeneic bone marrow, umbilical cord, or fresh MSCs, especially when non-human or unclear MSC culture media were used. However, MSC therapy significantly reduced mortality risk in patients with cardiovascular, neurological, and liver diseases.

The study concluded that MSC therapy does not correlate with acute infusion toxicity, infections, or malignancy development, although it remains associated with fever. The findings provide additional assurance to researchers, clinicians, regulators, patients, and their families regarding the safety and reliability of MSC therapy.

As stem cell research progresses, the diversity of MSC sources and the development of new-generation MSCs continue to be explored. Recent findings indicate that MSCs may express or increase proteins related to coagulation, presenting potential pro-coagulant effects depending on the clinical context. These effects could be beneficial or harmful, highlighting the need for ongoing monitoring and reporting of related adverse events in future studies.

Overall, this extensive review underscores that MSC therapy is a safe and effective treatment option, supporting its continued use and research in clinical applications.