Radiation rescue: mesenchymal stromal cells protect from lethal irradiation

Area of Science:

• Regenerative Medicine
• Hematopoietic Stem Cell Biology
• Radiation Oncology

Background:

• Acute radiation syndromes require immediate supportive care, with hematopoietic stem cell (HSC) transplantation as the only curative option for limited recovery potential.
• HSC transplantation is hindered by time-consuming donor searches and uncertain outcomes.
• Mesenchymal stromal cells (MSCs) are proposed as an alternative treatment for severe radiation exposure.

Purpose of the Study:

• To evaluate the efficacy of MSCs as a standalone treatment for radiation-induced hematopoietic failure.
• To investigate the underlying mechanisms of MSC-mediated protection and regeneration post-radiation.

Main Methods:

• Mouse MSCs (mMSCs) were expanded, labeled, and characterized for differentiation and phenotype.
• Lethally irradiated mice received intravenous transplantation of bulk or clonal mMSCs without HSC support.
• Gene expression analysis (microarray, RT-PCR) and chimerism analysis were performed.

Main Results:

• Long-term survival and rapid hematopoietic recovery were observed in MSC-transplanted recipients.
• Donor MSCs were detected transiently in peripheral blood and lungs but not long-term in tissues.
• MSC treatment enhanced bone marrow regenerative features, including decreased inflammation and boosted detoxification and stress control.

Conclusions:

• Systemically administered MSCs provide a protective mechanism against radiation-induced inflammation, supporting detoxification and stress management.
• MSCs, through trophic factors and HSC-niche modulation, rescue endogenous hematopoiesis.
• MSCs represent a fast and effective first-line treatment for radiation-induced hematopoietic failure.