Animal Models of Ligament Repair
Yuehuei H. An, Richard J. Friedman in Animal Models in Orthopaedic Research, 2020
Biochemical analyses show that the major component of connective tissues is water accounting for some 70% of the wet weight of the tissue (Table 1). The function of water in ligaments is somewhat moot; however, it has been suggested to be necessary for the intracellular transportation of ions as well contributing to the viscoelastic behavior of the tissue.28-30 The next most abundant component is collagen, of which type I collagen is the most ubiquitous. Collagen provides the structural mainstay of ligaments by providing a source of stability and mechanical integrity to the tissue. The remaining constituents (elastin, fibronectin and proteoglycans among others) are all matrix elements whose functions continue to be defined. Proteoglycans are thought to act as “shock absorbers” by altering ligament viscoelasticity via their water binding properties, while elastin may be responsible for the elastic properties of ligaments.14,15 Further research is required to elucidate the exact role of these substances in normal ligament function so that their levels and chemical composition can be optimized during post-traumatic repair.
Cellular and Molecular Basis of Human Biology
Lawrence S. Chan, William C. Tang in Engineering-Medicine, 2019
Structural proteins are responsible for creating a functional frameworks of human structure and function, like muscles, tendon, bone, cartilage, skin, hair, nail, etc. Although the major skeletal muscle proteins include common contractile proteins of slow type 1 and fast types 2A and 2X myosins, actins, tropomyosins, troponin complexes, and metabolic proteins, there is a high variability in terms of relative composition since muscle protein types vary with age, activity type and level, and gender (Gelfi et al. 2011). In bone, about 90% of protein is in the form of type I collagen (Lammi et al. 2006). In cartilage, type II collagen and aggrecans (large aggregating chondroitin sulfate proteoglycan) predominate (Lammi et al. 2006). In tendon, the major proteins are type I (most abundant), II, and III collagens (Buckley et al. 2013). For the skin, collagen is one of the major protein components. Hair and nail proteins are primarily keratins.
The Extracellular Matrix as a Substrate for Stem Cell Growth and Development and Tissue Repair
Richard K. Burt, Alberto M. Marmont in Stem Cell Therapy for Autoimmune Disease, 2019
Collagen types other than type I collagen exist in the ECM of virtually every tissue and organ, albeit in much lower quantities. These alternative collagen types each provide distinct mechanical and physical properties to the ECM and contribute to the population of ligands that interact with the resident cell populations. By way of example, Type III collagen exists within selected submucosal ECMs, such as the submucosal ECM of the urinary bladder; a location in which less rigid structure is required for appropriate function than is required in a tendinous or ligamentous location. Type IV collagen is present within the basement membrane of all vascular structures and is an important ligand for endothelial cells. Type VI collagen functions as a “connector” of glycosaminoglycan and functional proteins to larger structural proteins such as type I collagen, thus helping to provide a gel like consistency to the ECM. Type VII collagen is an essential component of the anchoring fibrils of keratinocytes to the underlying basement membrane of the epidermis. Each of these collagen types is of course the result of specific gene expression patterns as cells differentiate and tissues and organs develop and spatially organize.
Advances in the clinical use of collagen as biomarker of liver fibrosis
Published in Expert Review of Molecular Diagnostics, 2020
Steffen K. Meurer, Morten A. Karsdal, Ralf Weiskirchen
Collagen metabolism is one of the most complex and highly regulated processes in the organism. The actual net amount of an individual collagen results from its existing quantity, its new synthesis, and its degradation (see chapter 9). The biosynthesis of collagens requires transcription and splicing of its mRNA, translation into the protein product, posttranslational modification and assembly of the trimeric procollagen molecule. All these steps can be regulated at multiple levels. This is best documented for type I collagen being the most abundant protein in the human body. An average adult human contains about 3–5 kg of type I collagen, while based on the stability of this fibril-forming collagen having a half-life of 30–60 days, there is only a daily need to synthesize about 40 g of type I collagen [36]. However, the synthesis during wound healing and fibrosis significantly increases.
Histological study of costal cartilage after transplantation and reasons for avoidance of postoperative resorption and retention of cartilage structure in rats
Published in Journal of Plastic Surgery and Hand Surgery, 2018
Yukiko Rikimaru-Nishi, Hideaki Rikimaru, Shinichiro Hashiguchi, Tomonoshin Kanazawa, Keisuke Ohta, Kei-Ichiro Nakamura, Kensuke Kiyokawa
Type I collagen is distributed in the matrices of perichondrium and collagen type II is found uniformly throughout the hyaline cartilage extracellular matrix. Sections from the 40 cartilage specimens were incubated with blocking solution containing 3% normal goat serum and 0.5% Triton X-100 in PBS, followed by incubation overnight at 4 °C with anti-rabbit type I collagen or type II collagen polyclonal antiserum diluted with blocking solution (1:2000, Abcam plc, Cambridge, UK) and rinsing 4 times with PBS. Then the sections were reacted with ABC complex solution (Nacalai Tesque, Kyoto, Japan) and with 3,3′-diaminobenzidine tetrahydrochloride (DAB) according to the manufacturer’s instructions (DAB; Dako Japan, Kyoto, Japan). Finally, nuclei were counterstained with hematoxylin. For negative controls, appropriate solutions without the primary antibody were applied, instead of those with specific anticollagen antibodies [13].
Autologous conditioned serum for degenerative diseases and prospects
Published in Growth Factors, 2021
Seyed Kazem Shakouri, Sanam Dolati, Jessica Santhakumar, Avnesh S. Thakor, Reza Yarani
Rupture of the Achilles tendon is the most common tendon rupture in the adult population. Though conventional and surgical treatment methods are available, recent studies usually recommend surgical procedures (Maquirriain 2011). As a result of frequent and severe complications of Achilles tendon rupture treatments, post-operative additive biological procedures are typically performed (Sarıkaya et al. 2017; YükSel et al. 2015). ACS may be favorable for the treatment of human Achilles tendon injuries and tendinopathies (Genç et al. 2018). ACS treatment increased the expression of collagen I and had a significant effect on the histological appearance and mechanical resistance during tendon regeneration (Majewski et al. 2009). The ACS-treated tendons were thicker, had more type I collagen, and displayed an accelerated recovery of tendon stiffness and histologic maturity of the repair tissue (Geburek et al. 2015).