Optimization of adipose tissue-derived mesenchymal stromal cells transplantation for bone marrow repopulation following irradiation

BACKGROUND: Bone marrow (BM) suppression is one of the most common side effects of radiotherapy and the primary cause of death following exposure to irradiation. Despite concerted efforts, there is no definitive treatment method available. Recent studies have reported using mesenchymal stromal cells (MSCs), but their therapeutic effects are contested. AIM: We administered and examined the effects of various amounts of adipose-derived MSCs (ADSCs) in mice with radiation-induced BM suppression. METHODS: Mice were divided into three groups: Normal control group, irradiated (RT) group, and stem cell-treated group following whole-body irradiation (WBI). Mouse ADSCs (mADSCs) were transplanted into the peritoneal cavity either once or three times at 5 × 10(5) cells/200 μL. The white blood cell count and the levels of, plasma cytokines, BM mRNA, and BM surface markers were compared between the three groups. Human BM-derived CD34(+) hematopoietic progenitor cells were co-cultured with human ADSCs (hADSCs) or incubated in the presence of hADSCs conditioned media to investigate the effect on human cells in vitro. RESULTS: The survival rate of mice that received one transplant of mADSCs was higher than that of mice that received three transplants. Multiple transplantations of ADSCs delayed the repopulation of BM hematopoietic stem cells. Anti-inflammatory effects and M2 polarization by intraperitoneal ADSCs might suppress erythropoiesis and induce myelopoiesis in sub-lethally RT mice. CONCLUSION: The results suggested that an optimal amount of MSCs could improve survival rates post-WBI.