CD24 enrichment protects while its loss increases susceptibility of juvenile chondrocytes towards inflammation

Supplemental methods. (DOCX 73 kb

Proteomic analysis of platelet-rich and platelet-poor plasma

Background Autologous blood products, such as platelet-rich plasma (PRP) are commercial products broadly used to accelerate healing of tissues after injuries. However, their content is not standardized and significantly varies in composition, which may lead to differences in clinical efficacy. Also, the underlying molecular mechanisms for therapeutic effects are not well understood. Purpose A proteomic study was performed to compare the composition of low leukocyte PRP, platelet poor plasma (PPP), and blood plasma. Pathway analysis of the proteomic data was performed to evaluate differences between plasma formulations at the molecular level. Low abundance regulatory proteins in plasma were identified and quantified as well as cellular pathways regulated by those proteins. Methods Quantitative proteomic analysis, using multiplexed isotopically labeled tags (TMT labeling) and label-free tandem mass spectrometry, was performed on plasma, low leukocyte PRP, and PPP. Plasma formulations were derived from two blood donors (one donor per experiment). Pathway analysis of the proteomic data identified the major differences between formulations. Results Nearly 600 proteins were detected in three types of blood plasma formulations in two experiments. Identified proteins showed more than 50% overlap between plasma formulations. Detected proteins represented more than 100 canonical pathways, as was identified by pathway analysis. The major pathways and regulatory molecules were linked to inflammation. Conclusion Three types of plasma formulations were compared in two proteomic experiments. The most represented pathways, such as Acute Phase Response, Coagulation, or System of the Complement, had many proteins in common in both experiments. In both experiments plasma sample sets had the same direction of biochemical pathway changes: up- or down-regulation. The most represented biochemical pathways are linked to inflammation

Quantitation of progenitor cell populations and growth factors after bone marrow aspirate concentration

Background: The number of Mesenchymal Stem/Stromal Cells (MSCs) in the human bone marrow (BM) is small compared to other cell types. BM aspirate concentration (BMAC) may be used to increase numbers of MSCs, but the composition of MSC subpopulations and growth factors after processing are unknown. The purpose of this study was to assess the enrichment of stem/progenitor cells and growth factors in BM aspirate by two different commercial concentration devices versus standard BM aspiration. Methods: 120 mL of BM was aspirated from the iliac crest of 10 male donors. Each sample was processed simultaneously by either Emcyte GenesisCS® (Emcyte) or Harvest SmartPReP2 BMAC (Harvest) devices and compared to untreated BM aspirate. Samples were analyzed with multicolor flow cytometry for cellular viability and expression of stem/progenitor cells markers. Stem/progenitor cell content was verified by quantification of colony forming unit-fibroblasts (CFU-F). Platelet, red blood cell and total nucleated cell (TNC) content were determined using an automated hematology analyzer. Growth factors contents were analyzed with protein quantification assays. Statistical analyses were performed by ANOVA analysis of variance followed by Tukey’s multiple comparison test or Wilcoxon matched-pairs signed rank test with p < 0.05 for significance. Results: Cell viability after processing was approximately 90% in all groups. Compared to control, both devices significantly enriched TNCs and platelets, as well as the CD45−CD73+ and CD45−CD73+CD90+ cell populations. Further, Harvest significantly concentrated CD45−CD10+, CD45−CD29+, CD45−CD90+, CD45−CD105+, CD45−CD119+ cells, and CD45dimCD90+CD271+ MSCs, whereas Emcyte significantly enriched CD45dimCD44+CD271+ MSCs. BM concentration also increased the numbers of CFU-F, platelet-derived growth factor, vascular endothelial growth factor, macrophage colony-stimulating factor, interleukin-1b, VCAM-1 and total protein. Neither system concentrated red blood cells, hematopoietic stem cells or bone morphogenetic proteins. Conclusion: This data could contribute to the development of BMAC quality control assays as both BMAC systems concentrated platelets, growth factors and non-hematopoietic stem cell subpopulations with distinct phenotypes without loss of cell viability when compared to unprocessed BM

T2 relaxation times of knee cartilage in 109 patients with knee pain and its association with disease characteristics

Background and purpose — Quantitative T2 mapping MRI of cartilage has proven value for the assessment of early osteoarthritis changes in research. We evaluated knee cartilage T2 relaxation times in a clinical population with knee complaints and its association with patients and disease characteristics and clinical symptoms. Patients and methods — In this cross-sectional study, T2 mapping knee scans of 109 patients with knee pain who were referred for an MRI by an orthopedic surgeon were collected. T2 relaxation times were calculated in 6 femoral and tibial regions of interest of full-thickness tibiofemoral cartilage. Its associations with age, sex, BMI, duration of complaints, disease onset (acute/chronic), and clinical symptoms were assessed with multivariate regression analysis. Subgroups were created of patients with abnormalities expected to cause predominantly medial or lateral tibiofemoral cartilage ch

Outcomes of Arthroscopic Repair versus Observation in Older Patients

Objectives: Meniscal root tears occur in a bimodal distribution, affecting both young healthy athletes and older patients with early degenerative knees. Root tears lead to de-tensioning of the meniscus and have been associated with increased contact forces and cartilage damage. Management of older patients with root tears is controversial and the efficacy of different treatment options is unclear. The primary aim of this study is to compare the clinical outcomes of patients undergoing an all-inside arthroscopic repair technique versus non-operative management for posterior meniscal root tears. Methods: 48 patients diagnosed with a posterior meniscal root tear between 2006 and 2015 were identified and divided into 2 groups, the arthroscopic repair group (AR, 30 knees), and the observation group (O: 18 knees). The AR group underwent a meniscal root repair technique where two all-inside sutures were used to reduce the root back to its remnant (reduction sutures) thereby re-tensioning the meniscus. One mattress suture was then added to strengthen the repair and repair the construct to the posterior capsule. KOOS subscores (Symptoms, Pain, Activities of Daily Living (ADL), Sports and Rec, Quality of Life), Lysholm, Tegner, and VR12 PCS questionnaires were used as the primary outcome measures at a minimum 2 years follow-up. Differences in baseline patient characteristics between the surgical and non-surgical group were examined using Fisher’s exact tests for categorical variables and Mann-Whitney U tests for continuous variables. For changes from baseline to follow up between the surgical and non-surgical group, independent sample t-tests or Mann-Whitney U tests were conducted depending on normality. A Fisher’s exact test was also utilized to analyze the rates of conversation to total knee arthroplasty (TKA) between the surgical and non-surgical group. Results: There were significant changes in all baseline to follow up mean KOOS subscores (all subscores: p &lt; 0.001), Lysholm (p &lt; 0.001), Tegner (p = 0.0002), and VR12 PCS (p &lt; 0.001) scores for the AR group, while the O group had a significant difference in only mean KOOS pain (p = 0.003), KOOS ADL (p = 0.006), and VR12 PCS (p = 0.038) scores from baseline to follow-up. The AR group had a significantly larger increase from baseline to follow up in mean KOOS pain scores (32.0) compared to the O group (15.7) (p = 0.009), KOOS symptom scores (AR: 24.2, O: 9.3, p = 0.029) as well as in Lysholm scores (AR: 27.3 and O: 7.1; p = 0.016). During the follow-up period, 3.3% of patients in the AR group underwent a TKA, which was significantly lower than the 33.3% of patients in the O group (p = 0.008). The hazard of TKA conversion is estimated to be 93.2% lower for patients in the AR group compared to the O group (p = 0.013). Conclusion: Our study found a significant improvement in all clinical outcome scores in the AR group at 2-year follow-up. There was a significantly larger increase in KOOS pain, KOOS symptom, and Lysholm scores in the AR group compared to the O group. The AR group also had a significantly lower conversion to TKA and significantly lower hazard of TKA conversion as compared to the O group. Surgical management showed higher functional outcomes and decreased TKA conversion rates as compared to observation and should be considered as a treatment option for the treatment of meniscal root tears in the older population. </jats:sec