Good mid-term outcomes after adipose-derived culture-expanded mesenchymal stem cells implantation in knee focal cartilage defects.

PURPOSE: The purpose of the present study was to investigate the mid-term outcomes of a single-stage cell-based procedure in patients with knee focal symptomatic cartilage defects using matrix-induced culture-expanded autologous AD-MSCs. It was hypothesised that the increased number of autologous AD-MSCs after culture expansion is a safe and efficient cartilage repair procedure, which improves overtime chondrogenesis in cartilage lesions METHODS: Twenty-five consecutive patients treated for a symptomatic cartilage defect were prospectively followed for 3 years. The median age of patients was 30.5 (range 16-43) with a median BMI of 23.6 kg/m2 (range 19-29) and an average size of the lesion of 3.5 cm2 (range 2-6). All patients underwent a single-stage procedure consisting in filling each defect with autologous culture-expanded mesenchymal stem cells embedded in a trimmed-to-fit commercially available biodegradable matrix. Pre-operative and post-operative evaluation included knee-related clinical and functional evaluation based on objective and subjective scores at 6, 12, 24 and 36 months and MRI evaluation of the repair tissue using the MOCART score at 12 and 24 months. RESULTS: Clinical outcomes recorded significant improvements (p < 0.05) at the final follow-up compared with baseline as following: all subcategories of KOOS Score, the IKDC subjective from 40.9 (range 20.7-65.6) to 76.9 (range 42-90.3), Tegner Activity Score from 3 (range 2-4) to 4 (range 3-4), VAS for pain from 6 (range 4-8) to 1 (range 0-3). All patients improve significantly their IKDC objective scores. The MRI findings showed complete filling of the defect and integration to the border zone for 65% of the patients. Two patients underwent post-operative biopsies and the histological analysis demonstrated the presence of hyaline-like tissue. CONCLUSIONS: Adipose-derived culture-expanded mesenchymal stem cells were shown to be an efficient and safe single-stage cell-based procedure for symptomatic, full-thickness knee chondral lesions. The findings of the present study demonstrate that all patients presented significant mid-term clinical, functional and radiological improvement. LEVEL OF EVIDENCE: IV.

Efficient manufacturing of therapeutic mesenchymal stromal cells with the use of the Quantum Cell Expansion System.

BACKGROUND: The use of bone marrow-derived mesenchymal stromal cells (MSCs) as a cellular therapy for various diseases, such as graft-versus-host disease, diabetes, ischemic cardiomyopathy and Crohn's disease, has produced promising results in early-phase clinical trials. However, for widespread application and use in later phase studies, manufacture of these cells must be cost-effective, safe and reproducible. Current methods of manufacturing in flasks or cell factories are labor-intensive, involve a large number of open procedures and require prolonged culture times. METHODS: We evaluated the Quantum Cell Expansion System for the expansion of large numbers of MSCs from unprocessed bone marrow in a functionally closed system and compared the results with a flask-based method currently in clinical trials. RESULTS: After only two passages, we were able to expand a mean of 6.6 × 10(8) MSCs from 25 mL of bone marrow reproducibly. The mean expansion time was 21 days, and cells obtained were able to differentiate into all three lineages: chondrocytes, osteoblasts and adipocytes. The Quantum was able to generate the target cell number of 2.0 × 10(8) cells in an average of 9 fewer days and in half the number of passages required during flask-based expansion. We estimated that the Quantum would involve 133 open procedures versus 54,400 in flasks when manufacturing for a clinical trial. Quantum-expanded MSCs infused into an ischemic stroke rat model were therapeutically active. CONCLUSIONS: The Quantum is a novel method of generating high numbers of MSCs in less time and at lower passages when compared with flasks. In the Quantum, the risk of contamination is substantially reduced because of the substantial decrease in open procedures.

Qualifying stem cell sources: how to overcome potential pitfalls in regenerative medicine?

Regenerative medicine aims to replace lost cells and to restore damaged tissues and organs by either tissue-engineering approaches or stimulation of endogenous processes. Due to their biological properties, stem cells promise to be an effective source for such strategies. Especially adult multipotent stem cells (ASCs) are believed to be applicable in a broad range of therapies for the treatment of multifactorial diseases or age-related degeneration, although the molecular and cellular mechanisms underlying their regenerative function are often hardly described. Moreover, in some demanding clinical situations their efficiency remains limited. Thus, a basic understanding of ASCs regenerative function, their complex interplay with their microenvironment and how compromising conditions interfere with their efficiency is mandatory for any regenerative strategy. Concerning this matter, the impact of patient-specific constraints are often underestimated in research projects and their influence on the study results disregarded. Thus, researchers are urgently depending on well-characterized tissue samples or cells that are connected with corresponding donor information, such as secondary diseases, medication. Here, we outline principle pitfalls during experimental studies using human samples, and describe a potential strategy to overcome these challenges by establishing a core unit for cell and tissue harvesting. This facility aims to bridge the gap between clinic and research laboratories by the provision of a direct link to the clinical operating theatres. Such a strategy clearly supports basic and clinical research in the conduct of their studies and supplies highly characterized human samples together with the corresponding donor information.