Increased Chondroprotective Effect of Combining Hyaluronic Acid with a Glucocorticoid Compared to Separate Administration on Cytokine-Treated Osteoarthritic Chondrocytes in a 2D Culture.

Intra-articular injections of glucocorticoids (GC) or hyaluronic acid (HA) are commonly used interventions for patients suffering from knee osteoarthritis (OA). Both substances are combined to achieve a chondroprotective and anti-inflammatory effect. Clinical studies have shown benefits, but data on the cellular level are still lacking.

Biotribological Tests of Osteochondral Grafts after Treatment with Pro-Inflammatory Cytokines.

Objective: During osteoarthritis progression, cartilage degrades in a manner that influences its biomechanical and biotribological properties, while chondrocytes reduce the synthesis of extracellular matrix components and become apoptotic. This study investigates the effects of inflammation on cartilage under biomechanical stress using biotribological tests.

Methods: Bovine osteochondral grafts from five animals were punched out from the medial condyle and treated with or without pro-inflammatory cytokines (interleukin-1β [IL-1β], tumor necrosis factor-α [TNF-α], IL-6) for 2 weeks.

Concentration-Dependent Effects of Cobalt and Chromium Ions on Osteoarthritic Chondrocytes.

Objective: Cobalt and chromium (CoCr) ions from metal implants are released into the joint due to biotribocorrosion, inducing apoptosis and altering gene expression in various cell types. Here, we asked whether CoCr ions concentration-dependently changed viability, transcriptional activity, and inflammatory response in human articular chondrocytes.

Design: Human articular chondrocytes were exposed to Co (1.

Serum albumin-coated bone allograft (BoneAlbumin) results in faster bone formation and mechanically stronger bone in aging rats.

Serum albumin-coated bone allografts (BoneAlbumin) have successfully supported bone regeneration in various experimental models by activating endogenous progenitors. However, the effect of tissue aging, linked to declining stem cell function, has yet to be explicitly examined within the context of BoneAlbumin's regenerative capacity. Stem cell function was tested with an in vitro attachment assay, which showed that albumin coating increases stem cell attachment on demineralized bone surfaces in an aging cell population.

Effect of osteochondral graft orientation in a biotribological test system.

Autologous osteochondral transplantation (AOT) utilizing autografts is a widely used technique for the treatment of small-to-medium cartilage defects occurring in knee and ankle joints. The application of viable cartilage and bone ensures proper integration, early weight bearing, as well as restoration of biomechanical and biotribological properties. However, alignment of the autografts onto the defect site remains a pivotal aspect of reinstating the properties of the joint toward successful autograft integration.

Redifferentiation of Articular Chondrocytes by Hyperacute Serum and Platelet Rich Plasma in Collagen Type I Hydrogels.

Matrix-assisted autologous chondrocyte transplantation (MACT) for focal articular cartilage defects often fails to produce adequate cartilage-specific extracellular matrix in vitro and upon transplantation results in fibrocartilage due to dedifferentiation during cell expansion. This study aimed to redifferentiate the chondrocytes through supplementation of blood-products, such as hyperacute serum (HAS) and platelet-rich plasma (PRP) in vitro. Dedifferentiated monolayer chondrocytes embedded onto collagen type I hydrogels were redifferentiated through supplementation of 10% HAS or 10% PRP for 14 days in vitro under normoxia (20% O₂) and hypoxia (4% O₂).

Platelet-Rich Plasma Supports Proliferation and Redifferentiation of Chondrocytes during Expansion.

Articular cartilage regeneration is insufficient to restore sports injuries or defects that can occur from trauma. Treatment options for cartilage repair include autologous chondrocyte implantation (ACI) by isolation, expansion, and reimplantation of healthy donor chondrocytes. Chondrocyte expansion onto 2D substrates leads to dedifferentiation and loss of the cellular phenotype.

A protocol for gene expression analysis of chondrocytes from bovine osteochondral plugs used for biotribological applications.

RNA isolation from human or animal cartilage tissue is necessary when performing mechanical or biotribological applications. Despite no influence on the cells and no alterations in gene expression patterns, enzymatic digestion of tissues should be avoided as it's known that the expression of collagen 2 can be effected (Hayman et al., 2006 [1]).

Hyaluronan thiomer gel/matrix mediated healing of articular cartilage defects in New Zealand White rabbits-a pilot study.

Background: Articular cartilage defects are limited to their regenerative potential in human adults. Our current study evaluates tissue regeneration in a surgically induced empty defect site with hyaluronan thiomer as a provisional scaffold in a gel/matrix combination without cells on rabbit models to restore tissue formation.

Methods: An osteochondral defect of 4 mm in diameter and 5 mm in depth was induced by mechanical drilling in the femoral center of the trochlea in 18 New Zealand White rabbits.

Chondrogenic Gene Expression Differences between Chondrocytes from Osteoarthritic and Non-OA Trauma Joints in a 3D Collagen Type I Hydrogel.

Objective The purpose of the current study was to compare the donor age variation of chondrocytes from non-OA (osteoarthritic) trauma joints in patients of young to middle age (20.5 ± 3.7, 31.

Chondroprotective effect of high-molecular-weight hyaluronic acid on osteoarthritic chondrocytes in a co-cultivation inflammation model with M1 macrophages.

Background: Osteoarthritis (OA) is described by an imbalance between anabolic and catabolic processes in the affected joint. This dysregulation of metabolism affects not only chondrocytes within cartilage tissue but also the cells of the synovial membrane across the border of the joint. An important factor in OA is the low viscosity of the synovial fluid.

A Novel Cross-Linked Hyaluronic Acid Porous Scaffold for Cartilage Repair: An In Vitro Study With Osteoarthritic Chondrocytes.

Purpose: An important feature of biomaterials used in cartilage regeneration is their influence on the establishment and stabilization of a chondrocytic phenotype of embedded cells. The purpose of this study was to examine the effects of a porous 3-dimensional scaffold made of cross-linked hyaluronic acid on the expression and synthesis performance of human articular chondrocytes.

Materials And Methods: Osteoarthritic chondrocytes from 5 patients with a mean age of 74 years were passaged twice and cultured within the cross-linked hyaluronic acid scaffolds for 2 weeks.

Correlation Analysis of SOX9, -5, and -6 as well as COL2A1 and Aggrecan Gene Expression of Collagen I Implant-Derived and Osteoarthritic Chondrocytes.

Objective: Matrix-assisted autologous chondrocyte implantation is frequently applied to replace damaged cartilage in order to support tissue regeneration or repair and to prevent progressive cartilage degradation and osteoarthritis. Its application, however, is limited to primary defects and contraindicated in the case of osteoarthritis that is partially ascribed to dedifferentiation and phenotype alterations of chondrocytes obtainable from patients' biopsies. The differentiation state of chondrocytes is reflected at the level of structural gene (COL2A1, ACAN, COL1A1) and transcription factor (SOX9, 5, 6) expression.

Mechanostimulation changes the catabolic phenotype of human dedifferentiated osteoarthritic chondrocytes.

Purpose: The treatment of cartilage defects with matrix-embedded autologous chondrocytes is a promising method to support the repair process and to foster reconstitution of full functionality of the joint.

Methods: Human osteoarthritic chondrocytes were harvest from nine different patients (mean ± SD age 68 ± 8 years) who underwent total knee replacement. The chondrocytes were embedded after a precultivation phase into a collagen I hydrogel.

Investigation of bone allografts representing different steps of the bone bank procedure using the CAM-model.

Bone grafting is commonly used to treat large bone defects. Since autografts are limited and frequently associated with postoperative donor morbidity, allografts from bone banks are often used. However, vascularisation of the allograft is often impaired, resulting in inadequate bone healing and functional graft failure.

Investigation of Collagen Transplants Seeded with Human Autologous Chondrocytes at the Time of Transplantation.

Objective: The treatment of cartilage defects with matrix-embedded autologous chondrocytes is a promising method to support the repair process. In this study we gathered quality parameters of collagen I matrices and embedded autologous chondrocytes at the time of transplantation We determined number, morphology, and distribution of matrix-embedded chondrocytes as well as their synthesis performance concerning sulphated glycosaminoglycans (sGAG) and collagen 1A1 and 2A1 mRNA levels.

Results: Chondrocytes were equidistantly distributed in the collagen matrices, and cell numbers ranged from 6 to 34 × 10(4) cells/g wet weight.