Human Tibiofemoral Joint Displacements Determined by Displacement-Encoded MRI

Author(s):  
D. D. Chan ◽  
C. P. Neu

Articular cartilage and surrounding soft tissues in the knee are important to normal joint function. Osteoarthritis (OA) is highly prevalent in the United States [1] and features precocious degeneration of articular cartilage. Effective OA treatments require the ability to detect early degeneration, including mechanical and biochemical changes. Magnetic resonance imaging has shown promise for the detection of early degenerative changes, including various quantitative MRI techniques [2]. Displacement-encoded MRI has the ability to detect changes in mechanical behavior, and such techniques have previously been used in cartilage explants [3] and intact juvenile animal joints [4]. However, the authors are aware of no studies with displacement-encoded MRI of human articular cartilage. Tissue-level displacement patterns could be key to revealing early degeneration in articular cartilage. This study demonstrates for the first time displacement encoding with stimulated echoes (DENSE) in an adult human tibiofemoral joint.

2021 ◽  
Vol 22 (13) ◽  
pp. 6719
Author(s):  
Ashleigh M. Philp ◽  
Sam Butterworth ◽  
Edward T. Davis ◽  
Simon W. Jones

Obesity increases the risk of hip osteoarthritis (OA). Recent studies have shown that adipokine extracellular nicotinamide phosphoribosyltransferase (eNAMPT or visfatin) induces the production of IL-6 and matrix metalloproteases (MMPs) in chondrocytes, suggesting it may promote articular cartilage degradation. However, neither the functional effects of extracellular visfatin on human articular cartilage tissue, nor its expression in the joint of hip OA patients of varying BMI, have been reported. Hip OA joint tissues were collected from patients undergoing joint replacement surgery. Cartilage explants were stimulated with recombinant human visfatin. Pro-inflammatory cytokines and MMPs were measured by ELISA and Luminex. Localisation of visfatin expression in cartilage tissue was determined by immunohistochemistry. Cartilage matrix degradation was determined by quantifying proteoglycan release. Expression of visfatin was elevated in the synovial tissue of hip OA patients who were obese, and was co-localised with MMP-13 in areas of cartilage damage. Visfatin promoted the degradation of hip OA cartilage proteoglycan and induced the production of pro-inflammatory cytokines (IL-6, MCP-1, CCL20, and CCL4) and MMPs. The elevated expression of visfatin in the obese hip OA joint, and its functional effects on hip cartilage tissue, suggests it plays a central role in the loss of cartilage integrity in obese patients with hip OA.


Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 1052 ◽  
Author(s):  
Simonetta Carluccio ◽  
Daniela Martinelli ◽  
Maria Elisabetta Federica Palamà ◽  
Rui Cruz Pereira ◽  
Roberto Benelli ◽  
...  

Regenerative strategies for human articular cartilage are still challenging despite the presence of resident progenitor cell population. Today, many efforts in the field of regenerative medicine focus on the use of platelet derivatives due to their ability to reactivate endogenous mechanisms supporting tissue repair. While their use in orthopedics continues, mechanisms of action and efficacy need further characterization. We describe that the platelet lysate (PL) is able to activate chondro-progenitor cells in a terminally differentiated cartilage tissue. Primary cultures of human articular chondrocytes (ACs) and cartilage explants were set up from donor hip joint biopsies and were treated in vitro with PL. PL recruited a chondro-progenitors (CPCs)-enriched population from ex vivo cartilage culture, that showed high proliferation rate, clonogenicity and nestin expression. CPCs were positive for in vitro tri-lineage differentiation and formed hyaline cartilage-like tissue in vivo without hypertrophic fate. Moreover, the secretory profile of CPCs was analyzed, together with their migratory capabilities. Some CPC-features were also induced in PL-treated ACs compared to fetal bovine serum (FBS)-control ACs. PL treatment of human articular cartilage activates a stem cell niche responsive to injury. These facts can improve the PL therapeutic efficacy in cartilage applications.


Cartilage ◽  
2021 ◽  
pp. 194760352110476
Author(s):  
Yannick Nossin ◽  
Eric Farrell ◽  
Wendy J.L.M. Koevoet ◽  
Frank Datema ◽  
Rodrigo A. Somoza ◽  
...  

Objective Cartilage is avascular and numerous studies have identified the presence of single anti- and pro-angiogenic factors in cartilage. To better understand the maintenance hyaline cartilage, we assessed the angiogenic potential of complete cartilage releasate with functional assays in vitro and in vivo. Design We evaluated the gene expression profile of angiogenesis-related factors in healthy adult human articular cartilage with a transcriptome-wide analysis generated by next-generation RNAseq. The effect on angiogenesis of the releasate of cartilage tissue was assessed with a chick chorioallantoic membrane (CAM) assay as well as human umbilical vein endothelial cell (HUVEC) migration and proliferation assays using conditioned media generated from tissue-engineered cartilage derived from human articular and nasal septum chondrocytes as well as explants from bovine articular cartilage and human nasal septum. Experiments were done with triplicate samples of cartilage from 3 different donors. Results RNAseq data of 3 healthy human articular cartilage donors revealed that the majority of known angiogenesis-related factors expressed in healthy adult articular cartilage are pro-angiogenic. The releasate from generated cartilage as well as from tissue explants, demonstrated at least a 3.1-fold increase in HUVEC proliferation and migration indicating a pro-angiogenic effect of cartilage. Finally, the CAM assay demonstrated that cartilage explants can indeed attract vessels; however, their ingrowth was not observed. Conclusion Using multiple approaches, we show that cartilage releasate has an inherent pro-angiogenic capacity. It remains vessel free due to anti-invasive properties associated with the tissue itself.


Cartilage ◽  
2020 ◽  
pp. 194760352097324
Author(s):  
Wassif Kabir ◽  
Claudia Di Bella ◽  
Peter F.M. Choong ◽  
Cathal D. O’Connell

Objectives Recapitulating the mechanical properties of articular cartilage (AC) is vital to facilitate the clinical translation of cartilage tissue engineering. Prior to evaluation of tissue-engineered constructs, it is fundamental to investigate the biomechanical properties of native AC under sudden, prolonged, and cyclic loads in a practical manner. However, previous studies have typically reported only the response of native AC to one or other of these loading regimes. We therefore developed a streamlined testing protocol to characterize the elastic and viscoelastic properties of human knee AC, generating values for several important parameters from the same sample. Design Human AC was harvested from macroscopically normal regions of distal femoral condyles of patients ( n = 3) undergoing total knee arthroplasty. Indentation and unconfined compression tests were conducted under physiological conditions (temperature 37 °C and pH 7.4) and testing parameters (strain rates and loading frequency) to assess elastic and viscoelastic parameters. Results The biomechanical properties obtained were as follows: Poisson ratio (0.4 ± 0.1), instantaneous modulus (52.14 ± 9.47 MPa) at a loading rate of 1 mm/s, Young’s modulus (1.03 ± 0.48 MPa), equilibrium modulus (7.48 ± 4.42 MPa), compressive modulus (10.60 ± 3.62 MPa), dynamic modulus (7.71 ± 4.62 MPa) at 1 Hz and loss factor (0.11 ± 0.02). Conclusions The measurements fell within the range of reported values for human knee AC biomechanics. To the authors’ knowledge this study is the first to report such a range of biomechanical properties for human distal femoral AC. This protocol may facilitate the assessment of tissue-engineered composites for their functionality and biomechanical similarity to native AC prior to clinical trials.


Author(s):  
Nazli Caner ◽  
Jeffrey W. Ruberti

Articular cartilage is a specialized avascular connective tissue found at the contact regions of diarthrodial joints. Cartilage has few cells (< 5% of the volume), though these cells can maintain the balance of turnover in healthy tissue, when the tissue is damaged, they are not able to repair the defects [1–3]. Extra cellular matrix (ECM) in cartilage comprises water, collagen (principally type II), proteoglycans and noncollagenous proteins. The type II collagen network, which is the dominant structural protein in cartilage ECM, constrains the expansion of the resident PGs and is generally held in mechanical tension. In osteoarthritis (OA), the balance of cartilage tissue production/degradation is thought to be affected by abnormal mechanical stimuli leading to net matrix resorption through production of excess degradative enzymes (e.g. matrix metalloproteinases (MMP) and aggrecanases) [4–8]. In OA tissue the amount of MMP-13 is thought to be increased relative to healthy tissue. OA typically occurs in older adults where, as cartilage ages, there is a marked decrease in the fixed charge density (FCD), the hydration and, consequently, mechanical tension on the collagen type II network [9–11]. We have hypothesized that loss of tension on the collagen network accelerates degradation by MMP. Detection of the effect of MMP on loaded, native cartilage could lead to insight about cartilage degradation kinetics in OA. However, it is quite difficult to controllably deliver MMP to cartilage, to activate the MMP during detensioning of the collagen network and to detect the effect on the cartilage mechanics (because cost limits the amount of MMP used). We have developed a transpirational enzyme loading method which is capable of precisely dosing bovine cartilage explants with a small, known quantity of MMP-13. Following enzyme insertion, we are able to detect the activity of the MMP on osmotically compressed cartilage (i.e. cartilage with a detensioned collagen network) via a simple hydration measurement.


2002 ◽  
Vol 50 (10) ◽  
pp. 1313-1323 ◽  
Author(s):  
Ghada A. Nofal ◽  
Cheryl B. Knudson

The proteoglycan-rich extracellular matrix (ECM) directly associated with the cells of articular cartilage is anchored to the chondrocyte plasma membrane via interaction with the hyaluronan receptor CD44. The cytoplasmic tail of CD44 interacts with the cortical cytoskeleton. The objective of this study was to determine the role of the actin cytoskeleton in CD44-mediated matrix assembly by chondrocytes and cartilage matrix retention and homeostasis. Adult bovine articular cartilage tissue slices and isolated chondrocytes were treated with latrunculin or cytochalasin. Tissues were processed for histology and chondrocytes were examined for CD44 expression and pericellular matrix assembly. Treatments that disrupt the actin cytoskeleton reduced chondrocyte pericellular matrix assembly and the retention of proteoglycan within cartilage explants. There was enhanced detection of a neoepitope resulting from proteolysis of aggrecan. Cytoskeletal disruption did not reduce CD44 expression, as monitored by flow cytometry, but detergent extraction of CD44 was enhanced and hyaluronan binding was decreased. Thus, disruption of the cytoskeleton reduces the anchorage of CD44 in the chondrocyte membrane and the capacity of CD44 to bind its ligand. The results suggest that cytoskeletal disruption within cartilage uncouples chondrocytes from the matrix, resulting in altered metabolism and deleterious changes in matrix structure.


2007 ◽  
Vol 56 (2) ◽  
pp. 575-585 ◽  
Author(s):  
Ruo-Hua Song ◽  
Micky D. Tortorella ◽  
Anne-Marie Malfait ◽  
James T. Alston ◽  
Zhiyong Yang ◽  
...  

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Lauren A. Griffith ◽  
Katherine M. Arnold ◽  
Bram G. Sengers ◽  
Rahul S. Tare ◽  
Franchesca D. Houghton

AbstractArticular cartilage functions as a shock absorber and facilitates the free movement of joints. Currently, there are no therapeutic drugs that promote the healing of damaged articular cartilage. Limitations associated with the two clinically relevant cell populations, human articular chondrocytes and mesenchymal stem cells, necessitate finding an alternative cell source for cartilage repair. Human embryonic stem cells (hESCs) provide a readily accessible population of self-renewing, pluripotent cells with perceived immunoprivileged properties for cartilage generation. We have developed a robust method to generate 3D, scaffold-free, hyaline cartilage tissue constructs from hESCs that are composed of numerous chondrocytes in lacunae, embedded in an extracellular matrix containing Type II collagen, sulphated glycosaminoglycans and Aggrecan. The elastic (Young’s) modulus of the hESC-derived cartilage tissue constructs (0.91 ± 0.08 MPa) was comparable to full-thickness human articular cartilage (0.87 ± 0.09 MPa). Moreover, we have successfully scaled up the size of the scaffold-free, 3D hESC-derived cartilage tissue constructs to between 4.5 mm and 6 mm, thus enhancing their suitability for clinical application.


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