Abstract

A Therapeutic Alternative to Treat Focal Osteoarthritic Cartilage Lesions. Human mesenchymal stem cells (MSCs) are present in most of the tissue matrix, taking part in their regeneration when injury or damage occurs. The aim of this ArthroGenea®-AR was to investigate the presence of cells with pluripotential characteristics in synovial membranes from osteoarthritic (OA) patients and the capacity of these cells to differentiate to chondrocytes. Methods. Synovial membranes (n _ 8) from OA patients were digested with collagenase. Isolated cells were cultured with DMEM, 20% FBS, and FGFb10 ng/mL. Cells from second subculture were used to carry out phenotypic characterization experiments (flow cytometry analysis with 11 monoclonal antibodies) and chondrogenic differentiation experiments (micropellet cultured in chondrogenic medium). Chondrogenic differentiation of cells was assessment by quantification of cartilage extracellular matrix components by following techniques: Safranin O, Toluidine Blue, and Alcian Blue stains to detect proteoglycans and immunohistochemistry to detect type I and II collagen. Results. Flow cytometry analyses showed that in our population more than 90% of cells were positive for MSC markers: CD29 (95%), CD44 (90%), CD73 (95%), CD90 (98%). Cells were negative for hematopoietic markers (CD11b, CD34, and CD45). Furthermore, cells showed positive stain to multipotent markers such as CD117 (c-kit) (98%), CD166 (74%), and STRO-1 (88%) and to quiescent satellite cells like PAX-7 (35%). The micropellet analyses showed that the culture of these cells with TGFbeta-3 for 2 and 3 weeks stimulates proteoglycan and collagen type II synthesis. Both molecules are characteristic of hyaline articular cartilage. Conclusion. In this work, we demonstrate the presence of a cellular population with MSC characteristics in synovial tissue from OA patients.

Introduction

Osteoarthritis (OA) is characterized by an imbalance in cartilage and underlying subchondral bone homeostasis. We hypothesized that signals from the subchondral bone may modulate production of matrix components, alter chondrogenic differentiation potential of cocultured bone marrow-derived mesenchymal stem cells (BMSC) and induce a phenotypic shift in differentiated OA chondrocytes. As planning algorithms become increasingly accurate, quality assurance tests need to become more sophisticated to uncover discrepancies between reality and calculations which may only present themselves in complex geometrical situations (inhomogeneities etc.). Gel dosimetry and Monte Carlo simulations are capable of providing detailed dose information for comparison where more conventional dosimetry has limitations. In this work we aim to use both Monte Carlo calculations and polymer gel dosimetry to compare with results from a treatment planning system.

Methods

We established a novel coculture model between BMSC, mixed cultures (BMSC and chondrocytes) and chondrocytes embedded in fibrin gel with OA and normal subchondral bone explants (OAB and NB). Tissues and cells were either derived from OA or trauma patients. In addition, we used adipose-derived stem cells (ASC) from liposuction. With gene expression analysis, biochemical assays, immunofluorescence and biomechanical tests we characterized the properties of newly generated extracellular matrix (ECM) from chondrocytes and chondrogenically differentiating BMSC cocultured with OAB or NB in comparison with monocultures (cultures without bone explants). The standard method to calculate and optimize dose distributions for a patient treatment plan is based on fast analytical dose calculation (ADC) algorithms. These algorithms calculate dose along narrow width beams (pencils) with a certain spread. While more accurate dose calculation engines are available, they are not yet standard in clinical practice. The Monte Carlo (MC) simulation method is considered the gold standard to describe particle interactions and calculate the resulting dose.

Results

Our results suggest a variety of gel phantoms were constructed to test the performance of calculations in different situation such as homogeneous and inhomogeneous phantoms as an alteration of molecular composition and mechanical properties of the newly formed ECM in subchondral bone cocultures. We suggest that soluble factors, that is interleukins and bFGF, released in cocultures exert inhibitory effects on collagen and temporary effects on proteoglycan production, which finally results in a reduction of mechanical strength of newly formed fibrillar living networks of Mesenchymal stem cells Co-Cultured Chondrocytes Comprising Chondrogenic Autologous Treatment for patients with Osteoarthritis and large Cartilage defects on assessing the Clinical Impact of Approximations in Analytical Dose Calculations for Advanced Cell Therapy.