Chondrogenic Potential of Human Adult Mesenchymal Stem Cells is Independent of Age or Osteoarthritis Etiology

¹ NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany; TETEC AG, Aspenhaustrasse 25, 72770 Reutlingen, Germany
² Hospital for Workers Compensation Tübingen, Schnarrenbergstrasse 95, 72076 Tübingen, Germany
³ NMI Natural and Medical Sciences Institute at the University of Tübingen, Markwiesenstrasse 55, 72770 Reutlingen, Germany
⁴ University Clinic of Tübingen, Department of Internal Medicine, Medical Research Center, Otfried-Mueller-Strasse 27, 72076 Tübingen, Germany

^* To whom correspondence should be addressed. E-mail: reinout.stoop{at}tno.nl.

	Abstract

Osteoarthritis (OA) is a multifactorial disease strongly correlated with history of joint trauma, joint dysplasia, and advanced age. Mesenchymal stem cells (MSCs) are promising cells for biological cartilage regeneration. Conflicting data have been published concerning the availability of MSCs from the iliac crest, depending on age and overall physical fitness. Here, we analyzed whether the availability and chondrogenic differentiation capacity of MSCs isolated from the femoral shaft as an alternative source is age- or OA etiology-dependent. MSCs were isolated from the bone marrow (BM) of 98 patients, categorized into three OA-etiology groups (age-related, joint trauma, joint dysplasia) at the time of total hip replacement. All BM samples were characterized for cell yield, proliferation capacity, and phenotype. Chondrogenic differentiation was studied using micromass culture and analysed by histology, immunohistochemistry, and quantitative RT-PCR. Significant volumes of viable BM (up to 25 ml) could be harvested from the femoral shaft without observing donor-site morbidity, typically containing >10⁷ mononuclear cells/ml. No correlation of age or OA etiology with the number of mononuclear cells in BM, MSC yield, or cell size was found. Proliferative capacity and cellular spectrum of the harvested cells were independent of age and cause of OA. From all tested donors, MSCs could be differentiated into the chondrogenic lineage. We conclude that, irrespective of age and OA etiology, sufficient numbers of MSCs can be isolated and that these cells possess an adequate chondrogenic differentiation potential. Therefore, a therapeutic application of MSCs for cartilage regeneration of OA lesions seems feasible.