Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions. PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and QUADAS-2 analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared. 9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies. This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.
We hypothesise that the Masquelet induced membrane used for the reconstruction of large bone defects were likely to involve mesenchymal stem cells (MSCs), given the excellent resultant skeletal repair. This study represents the first characterisation in humans of the induced membrane formed as a result of the Masquelet technique. Induced membranes and matching periosteum were harvested from 7 patients. Cytokines (BMP2, VEGF, SDF1) and cell lineage markers (CD31, CD271, CD146) were studied by immunohistochemisty. Flow cytometry was used to measure the cellularity and cellular composition. MSCs were enumerated using a colony forming unit fibroblast assay. In expanded cultures, a 96-gene array card was used to assess their transcriptional profile. Alkaline phophatase, alizarin red and calcium assays were employed to measure their in vitro osteogenic potential Membrane was more cellular(p=0.028), had more MSC phenotype(p=0.043) compared to matched periosteum. The molecular profiles were similar, except for 2-fold abundance of SDF-1 in membrane (p=0.043)compared to periosteum. Membrane and periosteum had a similar proportion of endothelial cells and CFU-F colonies; expanded MSCs from both sources were highly osteogenic.Methods
Results
The aim of this study was to investigate PDGF release in the peripheral circulation following trauma and to correlate it with the numbers of MSCs in iliac crest bone marrow (BM) aspirate. Trauma patients with lower extremity fractures (n=18, age 21–64 years) were recruited prospectively. Peripheral blood was obtained on admission, and at 1, 3, 5 and 7 days following admission. The serum was collected and PDGF was measured using ELISA. Iliac crest (BM) aspirate (20ml) was obtained on days 0–9 following admission. MSCs were enumerated using standard colony-forming unit fibroblasts (CFU-F) assay.Objective
Methods
MSCs have long promised benefits of synthesising bone/cartilage, treating non-unions and potentially accelerating fracture repair. This potential has been tempered by MSC scarcity in the ‘gold-standard’ iliac crest bone marrow aspirate (ICBMA) and the resulting need to expand numbers via cell-culture. Culture of MSCs is time-consuming, expensive and results in cells with a reduced differentiation capacity. The reamer-irrigator-aspirator (RIA) is an innovation designed to reduce intra-medullary (IM) pressures during reaming of long-bones via continuous irrigation and suction. Aspirated contents are passed via a coarse filter, which traps bony-fragments before moving into a ‘waste’ bag - from which MSCs have been previously isolated. We examined liquid and solid phases found in this ‘waste’, performed a novel digestion of the solid phase and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA. The filtrate ‘waste’ bag from RIA reaming (6 patients) was filtered (70μm) and the solid fraction digested for 60min (37°C) with collagenase. MSCs were isolated from liquid & solid fractions and from 10ml matched ICBMA. Enumeration of MSCs was achieved via colony-forming-unit-fibroblast (CFUF) assay and flow-cytometry on fresh sample using CD45low, CD271+. MSCs were cultured by virtue of their plastic adherence and passaged in standard, non-haematopoietic media. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages with their phenotype assessed with flow cytometry CD33 CD34 CD45 CD73 CD90 CD105.Introduction
Methods
Although chondrocytes have been used for autologous implantation in defects of articular cartilage, limited availability and donor-site morbidity have led to the search for alternative cell sources. Mesenchymal stem cells from various sources represent one option. The infrapatellar fat-pad is a promising source. Advantages include low morbidity, ease of harvest and ex-vivo evidence of chondrogenesis. Expansion of MSCs from human fat-pad in FGF-2 has been shown to enhance chondrogenesis. To further elucidate this process, we assessed the role of TGF-?3, FGF-2 and oxygen tension on growth kinetics of these cells during expansion. Infrapatellar fatpads were obtained from 4 donors with osteoarthritis. Cells were expanded in various media formulations (STD, FGF, TGF and FGF/TGF) at both 20% and 5% oxygen tensions. Colony forming unit fibroblast assays were performed for each expansion group and assessed with crystal violet staining. Cell aggregates from each group underwent chondrogenic differentiation in 5% and atmospheric oxygen tension. Pellets were analyzed on day 21. 5% Oxygen tension during expansion increased the colony size for both FGF and FGF/TGF groups. Cells expanded in FGF/TGF proliferated more rapidly. Biochemical analysis revealed that cells expanded in FGF-2 had higher glycosaminoglycan synthesis rates, a marker for chondrogenesis. Differentiation at 5% pO2 led to higher levels of sGAG but its effect was generally less potent compared to expansion in FGF-2.Methods
Results
Iliac crest bone marrow aspirate (ICBMA) is frequently cited as the ‘gold-standard’ source of MSCs. Mesenchymal stem cells have been shown to reside within the intramedullary (IM) cavities of long-bones and a comparative assessment with ICBMA has not yet been performed. Aspiration of the IM cavities of 6 patients' femurs with matched ICBMA was performed. The long-bone-fatty-bone-marrow (LBFBM) aspirated was filtered (70μm) and the solid fraction digested for 60min (37°C) with collagenase. Enumeration was performed via the colony-forming-unit-fibroblast (CFU-F) assay and using the CD45low CD271+ phenotype via flow-cytometry. Passaged (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages with their phenotype assessed using flow-cytometry CD33 CD34 CD45 CD73 CD90 CD105.Introduction
Methods
Fracture healing represents a physiological process regulated by a variety of signalling molecules, growth factors and osteogenic progenitor cells. Bone healing following trauma is associated with increased serum concentrations of several pro-inflammatory and angiogenic growth factors1. Platelet-derived growth factor (PDGF) has been shown to stimulate mesenchymal stem cell (MSC) proliferation in vitro. However, the in vivo relationship between the levels of PDGF and the numbers of MSCs in humans has not yet been explored. The aim of this study was to investigate PDGF release in the peripheral circulation following trauma and to correlate it with the numbers of MSCs in iliac crest bone marrow (BM) aspirate and in peripheral blood. Trauma patients with lower extremity fractures (n=12, age 18-63 years) were recruited prospectively. Peripheral blood was obtained on admission, and at 1, 3, 5 and 7 days following admission. The serum was collected and PDGF was measured using the enzyme-linked immuno-sorbent assay (ELISA) technique. Iliac crest (BM) aspirate (20ml) and peripheral blood (PB) (20ml) was obtained on days 0-9 following admission. MSCs were enumerated using standard colony-forming unit fibroblasts (CFU-F) assay.Background and objectives
Methods
Iliac crest bone marrow aspirate (ICBMA) is frequently cited as the ‘gold-standard’ source of MSCs. MSCs have been shown to reside within the intramedullary (IM) cavities of long-bones [Nelea, 2005] however a comparative assessment with ICBMA has not yet been performed and the phenotype of the latter compartment MSCs remains undefined in their native environment. Aspiration of the IM cavities of 6 patients' femurs with matched ICBMA was performed. The long-bone-fatty-bone-marrow (LBFBM) was filtered (70μm) to separate liquid and solid fractions and the solid fraction was briefly (60min, 37oC) digested with collagenase. MSC enumeration was performed using the colony-forming-unit-fibroblast (CFU-F) assay and quantification of cells with the CD45low CD271+ phenotype by flow-cytometry. [Jones 2002, Buhring 2007] MSCs were cultured and standard expansion media and passage 2 cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages.Introduction
Methods
Therapeutic exploitation of MSCs in orthopaedics has been tempered by their scarcity within ‘gold-standard’ iliac crest bone marrow aspirate (ICBMA) and the resulting need to expand cells in vitro. This is time-consuming, expensive and results in cells with a reduced differentiation capacity. [Banfi 2000] The RIA is a device that provides continuous irrigation and suction during reaming of long bones. Aspirated contents pass via a filter, trapping bony-fragments, before moving into a ‘waste’ bag, from which MSCs have been previously isolated. [Porter 2009] We hypothesised that ‘waste’ RIA bag contains more MSCs than a standard aspirated volume of ICBMA (30 ml). We further hypothesised than a fatty solid phase within this ‘waste bag’ contains many MSCs trapped within the adipocyte-rich stromal network and hence requiring an enzymatic digestion for their efficient release [Jones 2006]. The discarded filtrate ‘waste’ bag that contained saline from marrow cavity irrigation procedure from RIA reaming (7 patients) was filtered (70μm) and the solid fraction digested for 60min (37oC) with collagenase. MSC enumeration was performed using the colony-forming-unit-fibroblast (CFU-F). Following culture in standard expansion media, passage 2 cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages and their phenotype was assessed using flow cytometry. ICBMA from the same patients was used as controls.Introduction
Methods
The scarcity of mesenchymal stem cells (MSCs) in iliac crest bone marrow aspirate (ICBMA), and the expense and time in culturing cells, has led to the search for alternative harvest sites. The reamer-irrigation-aspirator (RIA) provides continuous irrigation and suction during reaming of long bones. The aspirated contents pass via a filter, trapping bony fragments, before moving into a ‘waste’ bag from which MSCs have been previously isolated. We examined the liquid and solid phases, performed a novel digestion of the solid phase, and made a comparative assessment in terms of number, phenotype and differentiation capacity with matched ICBMA. The solid fraction from the filtrate was digested for 60 minutes at 37°C with collagenase. Enumeration was performed via the colony-forming unit fibroblast (CFU-F) assay. Passage (P2) cells were differentiated towards osteogenic, adipogenic and chondrogenic lineages, and their phenotypes assessed using flow cytometry (CD33, CD34, CD45, CD73, CD90, and CD105). MSCs from the RIA phases were able to differentiate at least as well as those from ICBMA, and all fractions had phenotypes consistent with other established sources. The median number of colonies for the three groups was: ICBMA = 8.5 (2 to 86), RIA-liquid = 19.5 (4 to 90), RIA-solid = 109 (67 to 200) per 200 μl. The mean total yield of cells for the three groups was: ICBMA = 920 (0 to 4275), RIA-liquid = 114 983 (16 500 to 477 750), RIA-solid = 12 785 (7210 to 28 475). The RIA filtrate contains large numbers of MSCs that could potentially be extracted without enzymatic digestion and used for bone repair without prior cell expansion.
