Orthopaedics
Kristen Davies in Core Conditions for Medical and Surgical Finals, 2020
Osteoarthritis (OA) is a disorder characterised by the progressive loss of articular cartilage and remodelling of the underlying bone and formation of osteophytes, which most commonly affects the knees, hips and small joints of the hands. OA is the most common arthropathy and is a leading cause of pain and disability in the UK. The prevalence of OA of the knees, hips and hands increases with age. The pathogenesis of OA is more complicated than a wear-and-tear phenomenon but this is how patients often perceive it. Research suggests that chondrocytes in articular cartilage are activated by an unknown trigger and release enzymes that break down the cartilage and expose the underlying bone. The classic examination findings for a hip fracture are pain in the affected hip, inability to weight bear on the affected leg, limited range of hip movement and the affected leg being shortened and externally rotated.
Skeletal Embryology and Limb Growth
Manoj Ramachandran, Tom Nunn in Basic Orthopaedic Sciences, 2018
During the early stages of development, the embryo has a laminar structure consisting of three different germ cell layers, from which specific systems will develop. The limb buds first appear at the end of the fourth week of development, with the forelimbs preceding the hindlimbs by 1-2 days. The anteroposterior axis (thumb to little finger) is regulated by the zone of polarizing activity (ZPA), a mass of cells within the posterior aspect of the limb bud. Amniotic band syndrome (ABS) is a congenital disorder believed to result from the entrapment of fetal limbs or organs within intrauterine fibrous amniotic bands, produced by partial rupture of the amniotic sac. The physis is a structure consisting of chondrocytes arranged in a highly ordered, layered fashion within an extracellular matrix in line with the longitudinal axis of the bone. Altering the forces acting upon the physis affects its activity, with compression retarding growth (Hueter-Volkmann principle).
Structure and Function of Cartilage
Kyriacos A. Athanasiou, Eric M. Darling, Grayson D. DuRaine, Jerry C. Hu, A. Hari Reddi in Articular Cartilage, 2017
This chapter covers the structure, composition, and function of articular cartilage, at the cell and extracellular matrix levels. All chondrocytes within articular cartilage share common traits with respect to gene and protein expressions, surface markers, and cell metabolism. The role of microtubules in intracellular transport is elegantly demonstrated in the assembly of the mitotic spindle, a structure that results in intracellular movement and segregation of replicated DNA into two daughter cells during mitosis. The territorial matrix exhibits higher concentration of proteoglycans than surrounding extracellular matrix, as well as having finer collagen structure. The biochemical structure of the matrix, both fluid and solid fractions, is intimately linked to mechanical function of cartilage. Structurally, intermediate filaments are 10 nm in diameter and "intermediate" in size, being smaller than microtubules but wider than actin microfilaments. In eukaryotic cells, cytoskeleton is comprised of three different filament types that can polymerize from soluble protein monomers into three-dimensional network that couples intracellular components to extracellular stimuli.
Chopping off the chondrocyte proteome
Published in Biomarkers, 2015
The progressive nature of osteoarthritis is manifested by the dynamic increase of degenerated articular cartilage, which is one of the major characteristics of this debilitating disease. As articular chondrocytes become exposed to inflammatory stress they enter a pro-catabolic state, which leads to the secretion and activation of a plethora of proteases. In aim to detect the disease before massive areas of cartilage are destroyed, various protein and non-protein biomarkers have been examined in bodily fluids and correlated with disease severity. This review will discuss the widely research extracellular degraded products as well as products generated by affected cellular pathways upon increased protease activity. While extracellular components could be more abundant, cleaved cellular proteins are less abundant and are suggested to possess a significant effect on cell metabolism and cartilage secretome. Subtle changes in cell secretome could potentially act as indicators of the chondrocyte metabolic and biological state. Therefore, it is envisioned that combined biomarkers composed of both cell and extracellular-degraded secretome could provide a valuable platform for testing drug efficacy to halt disease progression at its early stages.
Label-free proteomic analysis of the hydrophobic membrane protein complement in articular chondrocytes: a technique for identification of membrane biomarkers
Published in Biomarkers, 2015
Csaba Matta, Xiaofei Zhang, Susan Liddell, Julia R. Smith, Ali Mobasheri
Context: There is insufficient knowledge about the chondrocyte membranome and its molecular composition. Objective: To develop a Triton X-114 based separation technique using nanoLC-MS/MS combined with shotgun proteomics to identify chondrocyte membrane proteins. Materials and methods: Articular chondrocytes from equine metacarpophalangeal joints were separated into hydrophobic and hydrophilic fractions; trypsin-digested proteins were analysed by nanoLC-MS/MS. Results: A total of 315 proteins were identified. The phase extraction method yielded a high proportion of membrane proteins (56%) including CD276, S100-A6 and three VDAC isoforms. Discussion: Defining the chondrocyte membranome is likely to reveal new biomarker targets for conventional and biological drug discovery.
Characterization of chondrocytes cultured on catechin-loaded alginate-chitosan scaffolds
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2013
Mustafa Türk, Siyami Karahan, Miyase Çinar, Şebnem Küçük, Güngör Çagdaş Dinçel
Bovine chondrocytes were seeded into scaffolds of a high molecular weight chitosan and alginate with a pore size of 50–350 μm with or without catechin. In polymerase chain reaction (PCR), unlike type II, collagen type I was no longer expressed at day 14. The DNA content increased until day 8 and began declining, indicating cell detachment. The GAG content increased during the first 12 days. The percentage of round and collagen type II immunoreactive cells increased over the time. Catechin has some protective properties on chondrocytes seeded on the alginate-chitosan scaffolds during the first 12 days by means of DNA and chondrocyte morphology (p < 0.05).
Related Knowledge Centers
- Adipocytes
- Cartilage
- Connective Tissue Cells
- Fibroblasts
- Osteoblast
- Collagen For Wound Healing
- Hypertrophy