Hypo-Osmolarity Decreases the Ability of Cells in Articular Cartilage to Survive a Load-Induced Injury

2003 ◽  
Author(s):  
Adam Levin ◽  
Peter A. Torzilli ◽  
C. T. Christopher Chen
Keyword(s):  
Cell Death ◽  
Articular Cartilage ◽  
Cell Viability ◽  
Cartilage Explants ◽  
Hypotonic Solution ◽  
Pericellular Matrix ◽  
Isotonic Solution ◽  
Confined Compression ◽  
Superficial Zone ◽  
Bovine Cartilage

A recent study showed that exposure to hypotonic conditions increased chondrocyte surface area up to 234% by stretching the folded membrane, which may reduce the chondrocyte’s ability to deform under load. The goal of this study was to determine the effect of hypo-osmolarity on chondrocyte survival from load-induced injury. Bovine cartilage explants were incubated in either isotonic or hypotonic pH-buffered solution for 20 minutes, loaded with cyclic confined compression at 5MPa for 1 hour, and then assessed for cell viability using cell vital dyes and for pericellular matrix (PCM) using an type VI collagen antibody. Cell death in loaded explants was significantly greater than that of non-loaded controls (p<0.001). However, explants loaded in the hypotonic solution showed significantly greater cell death than those loaded in the isotonic solution. An increase of dead cells with flatten PCM were located in the superficial zone. Our findings suggest that hypo-osmolarity decreases the ability of chondrocytes in articular cartilage to survive from load-induced injury.

Ameliorating Glycosaminoglycan (GAG) Loss and Cell Death in Articular Cartilage Following Single-Impact Loading

2007 ◽  
Author(s):  
Roman M. Natoli ◽  
Kyriacos A. Athanasiou
Keyword(s):  
Extracellular Matrix ◽  
Cell Death ◽  
Articular Cartilage ◽  
Impact Loading ◽  
Biomechanical Properties ◽  
Cartilage Explants ◽  
Single Impact ◽  
Igf I ◽  
Post Traumatic ◽  
Bioactive Agents

Impact loading of articular cartilage leads to post-traumatic osteoarthritis (OA) through its effects on the cells and extracellular matrix (ECM) of the tissue. Studies have shown the level of impact or injurious compression correlates with increased cell death, degradation of the ECM, and detrimental changes in biomechanical properties [1]. Recently, several bioactive agents, such as P188 and IGF-I, have shown promising results by reducing cell death following injurious compression of cartilage explants [2, 3].

scholarly journals Raman Needle Arthroscopy for In Vivo Molecular Assessment of Cartilage

2021 ◽  
Author(s):  
Kimberly Kroupa ◽  
Man I Wu ◽  
Juncheng Zhang ◽  
Magnus Jensen ◽  
Wei Wong ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Low Cost ◽  
Femoral Condyle ◽  
Cartilage Explants ◽  
Anatomical Site ◽  
Superficial Zone ◽  
Human Cartilage ◽  
Polarized Raman ◽  
Bovine Cartilage

The development of treatments for osteoarthritis (OA) is burdened by the lack of standardized biomarkers of cartilage health that can be applied in clinical trials. We present a novel arthroscopic Raman probe that can optically biopsy cartilage and quantify key ECM biomarkers for determining cartilage composition, structure, and material properties in health and disease. Technological and analytical innovations to optimize Raman analysis include: 1) multivariate decomposition of cartilage Raman spectra into ECM-constituent-specific biomarkers (glycosaminoglycan [GAG], collagen [COL], water [H2O] scores), and 2) multiplexed polarized Raman spectroscopy to quantify superficial zone collagen anisotropy via a PLS-DA-derived Raman collagen alignment factor (RCAF). Raman measurements were performed on a series of ex vivo cartilage models: 1) chemically GAG-depleted bovine cartilage explants (n=40), 2) mechanically abraded bovine cartilage explants (n=30), 3) aging human cartilage explants (n=14), and 4) anatomical-site-varied ovine osteochondral explants (n=6). Derived Raman GAG score biomarkers predicted 95%, 66%, and 96% of the variation in GAG content of GAG-depleted bovine explants, human explants, and ovine explants, respectively (p<0.001). RCAF values were significantly different for explants with abrasion-induced superficial zone collagen loss (p<0.001). The multivariate linear regression of Raman-derived ECM biomarkers (GAG and H2O scores) predicted 94% of the variation in elastic modulus of ovine explants (p<0.001). Finally, we demonstrated the first in vivo Raman arthroscopy assessment of an ovine femoral condyle through intraarticular entry into the synovial capsule. This work advances Raman arthroscopy towards a transformative low cost, minimally invasive diagnostic platform for objective monitoring of treatment outcomes from emerging OA therapies.

Effect of Impact Load on Articular Cartilage: Cell Metabolism and Viability, and Matrix Water Content

1999 ◽  
Vol 121 (5) ◽  
pp. 433-441 ◽  
Author(s):  
P. A. Torzilli ◽  
R. Grigiene ◽  
J. Borrelli ◽  
D. L. Helfet
Keyword(s):  
Cell Death ◽  
Water Content ◽  
Impact Load ◽  
Cell Metabolism ◽  
Cartilage Explants ◽  
Critical Threshold ◽  
Limited Information ◽  
Impact Stress ◽  
Stress Dependent ◽  
Bovine Cartilage

Significant evidence exists that trauma to a joint produced by a single impact load below that which causes subchondral bone fracture can result in permanent damage to the cartilage matrix, including surface fissures, loss of proteoglycan, and cell death. Limited information exists, however, on the effect of a varying impact stress on chondrocyte biophysiology and matrix integrity. Based on our previous work, we hypothesized that a stress-dependent response exists for both the chondrocyte’s metabolic activity and viability and the matrix’s hydration. This hypothesis was tested by impacting bovine cartilage explants with nominal stresses ranging from 0.5 to 65 MPa and measuring proteoglycan biosynthesis, cell viability, and water content immediately after impaction and 24 hours later. We found that proteoglycan biosynthesis decreased and water content increased with increasing impact stress. However, there appeared to be a critical threshold stress (15–20 MPa) that caused cell death and apparent rupture of the collagen fiber matrix at the time of impaction. We concluded that the cell death and collagen rupture are responsible for the observed alterations in the tissue’s metabolism and water content, respectively, although the exact mechanism causing this damage could not be determined.

scholarly journals Latrunculin and Cytochalasin Decrease Chondrocyte Matrix Retention

2002 ◽  
Vol 50 (10) ◽  
pp. 1313-1323 ◽  
Author(s):  
Ghada A. Nofal ◽  
Cheryl B. Knudson
Keyword(s):  
Articular Cartilage ◽  
Actin Cytoskeleton ◽  
Cartilage Explants ◽  
Cartilage Tissue ◽  
Pericellular Matrix ◽  
Matrix Assembly ◽  
Tissue Slices ◽  
Cd44 Expression ◽  
Bovine Articular Cartilage ◽  
Cytoskeletal Disruption

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.

Analysis of Stored Osteochondral Allografts at the Time of Surgical Implantation

2005 ◽  
Vol 33 (10) ◽  
pp. 1479-1484 ◽  
Author(s):  
R. Todd Allen ◽  
Catherine M. Robertson ◽  
Andrew T. Pennock ◽  
William D. Bugbee ◽  
Frederick L. Harwood ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Cell Viability ◽  
Cell Density ◽  
Tissue Bank ◽  
Viable Cell ◽  
Viable Cell Density ◽  
Proteoglycan Synthesis ◽  
Superficial Zone ◽  
Chondrocyte Viability ◽  
Osteochondral Allografts

Background To date, the morphological, biochemical, and biomechanical characteristics of articular cartilage in osteochondral allografts that have been stored have not been fully described. Hypothesis Osteochondral allografts procured and stored commercially for a standard period as determined by tissue banking protocol will have compromised chondrocyte viability but preserved extracellular matrix quality. Study Design Controlled laboratory study. Methods Unused cartilage from 16 consecutive osteochondral allografts was sampled during surgery after tissue bank processing and storage. Ten grafts were examined for cell viability and viable cell density using confocal microscopy, proteoglycan synthesis via 35SO4 uptake, and glycosaminoglycan content and compared with fresh cadaveric articular cartilage. Biomechanical assessment was performed on the 6 remaining grafts by measuring the indentation stiffness of the cartilage. Results The mean storage time for the transplanted specimens was 20.3 ± 2.9 days. Chondrocyte viability, viable cell density, and 35SO4 uptake were significantly lower in allografts at implantation when compared to fresh, unstored controls, whereas matrix characteristics, specifically glycosaminoglycan content and biomechanical measures, were unchanged. In addition, chondrocyte viability in the stored allografts was preferentially decreased in the superficial zone of cartilage. Conclusion Human osteochondral allografts stored for a standard period (approximately 3 weeks) before implantation undergo decreases in cell viability, especially in the critically important superficial zone, as well as in cell density and metabolic activity, whereas matrix and biomechanical characteristics appear conserved. The exact clinical significance of these findings, however, is unknown, as there are no prospective studies examining clinical outcomes using grafts stored for extended periods. Clinical Relevance Surgeons who perform this procedure should understand the cartilage characteristics of the graft after 21 days of commercial storage in serum-free media.

scholarly journals Effect of tissue maturity on cell viability in load-injured articular cartilage explants

2005 ◽  
Vol 13 (6) ◽  
pp. 488-496 ◽  
Author(s):  
Adam S. Levin ◽  
Chih-Tung Christopher Chen ◽  
Peter A. Torzilli
Keyword(s):  
Articular Cartilage ◽  
Cell Viability ◽  
Cartilage Explants

Determination of In Situ Articular Cartilage Pericellular Matrix Properties via Inverse BEM Analysis of Chondron Deformation

2010 ◽  
Author(s):  
Eunjung Kim ◽  
Farshid Guilak ◽  
Mansoor A. Haider
Keyword(s):  
Articular Cartilage ◽  
Compressive Strain ◽  
Critical Role ◽  
Three Dimensional ◽  
Cartilage Explants ◽  
Pericellular Matrix ◽  
Type Vi Collagen ◽  
Microscopy Technique

The pericellular matrix (PCM) of articular cartilage is the narrow tissue region surrounding all chondrocytes. Together, the chondrocyte and its surrounding PCM have been termed the chondron. In normal cartilage, the presence of type VI collagen is exclusive to the PCM, and the PCM is believed to play a critical role in regulating biomechanical cell-matrix interactions. Since the PCM is stiffer than the chondrocyte, it has been hypothesized to play a critical role in protecting the cell while, simultaneously, facilitating the transmission of mechanical signals to the cell. Previous studies that represent the cell, PCM and extracellular matrix (ECM) as linear biphasic materials have supported this hypothesized role for the PCM [1–4]. Previous in vitro micropipette studies of isolated chondrons [5–7] have shown that the PCM Young’s modulus ranges between 25–70kPa in middle and deep zone cartilage, separating it by an order of magnitude from both the chondrocyte stiffness (∼1kPa) and ECM stiffness (∼1MPa). In recent years, Choi et al. [8] measured changes in the three-dimensional morphology of the chondron, in situ within the ECM, under equilibrium unconfined compression of porcine cartilage explants subjected to 10–50% compressive strain (Fig. 1). Their study employed a novel 3D confocal microscopy technique, based on immunolabeling of type VI collagen, that yielded ellipsoidal approximations of undeformed and deformed chondron shapes in the superficial, middle and deep zones of the explant. In this study, an efficient computational model, based on the boundary element method (BEM), was developed and used to estimate cartilage PCM linear elastic properties based on the data reported in Choi et al. [8] for the case of middle zone cartilage under 10% compressive strain.

scholarly journals Articular-cartilage matrix γ-carboxyglutamic acid-containing protein. Characterization and immunolocalization

1992 ◽  
Vol 282 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R Loeser ◽  
C S Carlson ◽  
H Tulli ◽  
W G Jerome ◽  
L Miller ◽  
...  
Keyword(s):  
Articular Cartilage ◽  
Matrix Vesicles ◽  
Protein Characterization ◽  
Pericellular Matrix ◽  
Guanidinium Chloride ◽  
Carboxyglutamic Acid ◽  
The Matrix ◽  
Important Regulator ◽  
Immunohistochemical Studies ◽  
Bovine Cartilage

Matrix gamma-carboxyglutamic acid (Gla)-containing protein (MGP) was found to be present in articular cartilage by Western-blot analysis of guanidinium chloride extracts of human and bovine cartilage and was further localized by immunohistochemical studies on human and monkey specimens. In newborn articular cartilage MGP was present diffusely throughout the matrix, whereas in growth-plate cartilage it was seen mainly in late hypertrophic and calcifying-zone chondrocytes. In adult articular cartilage MGP was present primarily in chondrocytes and the pericellular matrix. Immunoelectron microscopy studies revealed an association between MGP and vesicular structures with an appearance consistent with matrix vesicles. MGP may be an important regulator of cartilage calcification because of its localization in cartilage and the known affinity of Gla-containing proteins for Ca2+ and hydroxyapatite.

Sign in / Sign up

Export Citation Format

Share Document