Purpose: Many similarities between adipose derived stem cells (ASC’s) and bone marrow derived stem cells have been described in the literature. Importantly, both sources can give rise to hematopoietic cells. This study aims to determine if migratory bone marrow stem cells repopulate the adipose stem cell pool, or if these stem cell pools exist in two separate compartments. If the latter is true, then autogenous ASC’s might be free of the genetic mutations found in hematopoietic malignancies and possibly be used in place of allogeneic bone marrow transplant. To answer this question we examined tissue specimens from patients with two disease states: 1)Chronic Myeloid Leukemia (CML), and 2) history of bone marrow transplant (BMT).
Methods: Adipose biopsies and blood samples were taken from BMT recipients and short tandem repeat (STR) DNA sequences were analyzed to distinguish cells of donor and recipient origin. Adipose biopsies were also taken from patients with CML and evaluated for the presence of the BCR/ABL mutation in ASC’s via FISH and PCR. Only adherent ASC’s were studied to ensure there were no “passenger” hematopoietic cells present. The adipose derived stem cells were then differentiated into hematopoeitic cells using methylcellulose culture, as well as into other lineages to demonstrate multipotency.
Results: BMT patients demonstrated 100% engraftment of donor stem cells in peripheral blood samples. However, ASC’s from the same patients were entirely of host origin. In patients with CML testing positive for the BCR/ABL mutation in blood and bone marrow, autogenous ASC’s were free of this mutation by both FISH and PCR. Furthermore, these cells were successfully differentiated into monocytoid and erythroid colonies.
Conclusion: There appears to be no migration of bone marrow stem cells into the adipose stem cell compartment. This work suggests that the ASC population, while similar in function to bone marrow stem cells, is an independent pool of multipotent cells. This study also suggests that autogenous ASC’s could be used to repopulate the hematopoietic system in the setting of blood malignancies.