Bone marrow mesenchymal stem cell aspirates from alternative sources: is the knee as good as the iliac crest?
BACKGROUND
The most common method to obtain human mesenchymal stem cells (MSCs) is bone marrow aspiration from the iliac crest, but MSCs have also been isolated from different bones. The main purpose of this study was to compare bone marrow MSCs aspirated from the metaphysis of the distal femur and the proximal tibia with those obtained from the iliac crest, and to determine whether these locations represent potential alternative sources of MSCs for research and clinical application.


METHODS
Bone marrow was aspirated from the iliac crest and the metaphysis of the distal femur and the proximal tibia during total knee arthroplasty in 20 patients. The aspirates were centrifuged by density gradient, then mononucleated cell (MNC) concentration in the different aspirates was determined using a Coulter counter. MSCs were isolated, cultivated and characterised by their immunophenotype and by their in vitro potential for differentiation into osteoblasts, chondroblasts and adipocytes in specific media. Expansion and cell viability were quantified using trypan blue staining and cell counting with a haemocytometer (Neubauer chamber). The three sources were compared in terms of MNC concentration, viability of the cultures and presence of MSC using the Wilcoxon test.


RESULTS
MNC concentration was significantly higher in the iliac crest (10.05 Millions/ml) compared with the femur (0.67 Millions/ml) and tibia (1.7 Millions/ml). Culture success rates were 90%, 71% and 47% for MSCs from the iliac crest, femur and tibia, respectively. Flow cytometry analysis showed the presence of CD90+, CD105+, CD73+, VEGF+, CD71+, HLA-DR-, CD45-, CD34-, CD19-, and CD14- cells. The immunophenotype pattern of MSCs was similar for the three locations. Trilineage differentiation was achieved with all samples.


CONCLUSIONS
MSCs can be found in bone marrow from the metaphysis of both the distal femur and the proximal tibia. The phenotype and differentiation potential of these cells are similar to those of bone marrow MSCs from the iliac crest. Bone marrow aspiration from these locations is a relatively easy and safe alternative to that from the iliac crest for obtaining MSCs. Further study is required to assess whether the concentrations of MSCs obtained from these sources are sufficient for one-step therapeutic purposes.
Orthopaedics Department, Hospital General Universitario Gregorio Marañon, Madrid, Spain. Electronic address: franciscojavier.narbona@salud.madrid.org.
Javier
J
Narbona-Carceles
Orthopaedics Department, Hospital General Universitario Gregorio Marañon, Madrid, Spain.
Javier
J
Vaquero
Regenerative Medicine and Cellular Therapy Unit, Hospital General Universitario Gregorio Marañon, Madrid, Spain.
Susana  B S
S
Suárez-Sancho
School of Medicine, University San Pablo CEU, Campus Monteprincipe, Boadilla del Monte, Madrid, Spain.
Francisco
F
Forriol
Regenerative Medicine and Cellular Therapy Unit, Hospital General Universitario Gregorio Marañon, Madrid, Spain.
Maria Eugenia
ME
Fernández-Santos
D000368:Aged; D001854:Bone Marrow Cells / Q000166:cytology* / Q000502:physiology; D018929:Cell Culture Techniques / Q000379:methods*; D005260:Female; D006801:Humans; D007085:Ilium / Q000166:cytology*; D007719:Knee Joint / Q000166:cytology*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000502:physiology; D008875:Middle Aged
Aspiration; Bone marrow; Iliac crest; Knee; Mesenchymal stem cells; Regenerative