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Paper 2
Published in Aalia Khan, Ramsey Jabbour, Almas Rehman, nMRCGP Applied Knowledge Test Study Guide, 2021
Aalia Khan, Ramsey Jabbour, Almas Rehman
The risk of osteoporosis is greatest in thin Caucasian women. The B poly morphism of the Vitamin D receptor gene is over-represented in women with low postmenopausal bone density. Peak bone mass in adulthood is 80% controlled by genetic factors. Exhibiting polymorphism for the Type I collagen gene will increase the risk of osteoporotic fractures. A family history of osteoporosis increases risk. Reference: www.gpnotebook.co.uk
Comparative Anatomy, Physiology, and Biochemistry of Mammalian Skin
Published in David W. Hobson, Dermal and Ocular Toxicology, 2020
Five types of collagen fibers have been described in the human. The difference between the types is based on amino acid composition and sequence. Type I collagen is found in the dermis, bone, tendons, ligament, and dentin. Type II collagen is found predominantly in hyaline cartilage. Type III is found in the fetal dermis, uterus, and cardiovascular system, and immunofluorescent studies show it to be localized in the papillary dermis. Type IV is found in the basal lamina.202–204 Type V collagen, also known as AB, is found in the cornea, dermis, placental membranes, and lung. This type of collagen is thought to be important in cell movement.205
Tissue Responses to Infection and Injury
Published in Jeremy R. Jass, Understanding Pathology, 2020
The extracellular matrix of granulation tissue and fibrous tissue comprises several types of extracellular protein. The most important of these in terms of its quantity and tensile strength is collagen. There are different types of collagen, some forming fibrils with a distinct architectural structure at the electron microscope level and others being amorphous. Type I collagen is fibrillary and is the most common type, being found in skin, bone, tendon and scar tissue produced in the course of healing. At the electron microscopic level, type I collagen consists of bundles of fibres with regular transverse bands. Basement membrane type IV collagen, by contrast, is amorphous.
LncRNA AWPPH is downregulated in osteoporosis and regulates type I collagen α1 and α2 ratio
Published in Archives of Physiology and Biochemistry, 2022
Guang Qian, Yueming Yu, Youhai Dong, Yang Hong, Minghai Wang
Altered bone homeostasis is a major cause of osteoporosis (Aggarwal et al. 2012), while the balance between the activities of osteoblast and osteoclast determines bone homeostasis (Aggarwal et al. 2012). Osteoblasts create new bone, and the abnormal phenotype of osteoblasts contributes to the development of osteoporosis (Aggarwal et al. 2012). It is known that type I collagen α1 to α2 ratio regulates the phenotype of osteoblasts (Mann et al. 2001, Jin et al. 2009). Therefore, the regulation of type I collagen α1 to α2 ratio might contribute to the treatment of osteoporosis. Emerging evidence has shown that the biological behaviours of osteoblast and osteoclast can be regulated by long non-coding RNAs (lncRNAs) (Hu et al. 2018, Nardocci et al. 2018), which is a subgroup of non-coding RNAs composed of more than 200 nucleotides (Hu et al. 2018). LncRNAs play essential roles in human diseases, including osteoporosis (Shi et al. 2013, Hu et al. 2018, Nardocci et al. 2018, Mulati et al. 2020). LncRNA AWPPH has been reported as oncogenic lncRNA in several types of human cancer (Zhao et al. 2017, Wang et al. 2018, Zhu et al. 2018), while its role in osteoporosis is unknown. We performed RNA-seq analysis and found that the expression of lncRNA AWPPH was altered in osteoporosis, indicating its involvement in this disease. In the present study, we found that lncRNA AWPPH was downregulated in osteoporosis and altered the expression of lncRNA AWPPH regulated type I collagen α1 and α2 ratio in osteoblasts.
Fetal Skeletal Dysplasias: Radiologic-Pathologic Classification of 72 Cases
Published in Fetal and Pediatric Pathology, 2022
The OI is caused by haploinsufficiency of type I collagen, which is a ubiquitous protein and is the main constituent of the bone matrix. The type I collagen deficiency results in endochondral and intramembranous ossification defects as well as tissue and bone fragility. It is microscopically characterized by poor and irregular ossification with scarce, thin and disorganized bone trabeculae, contrasting with a normal appearance of the growth plate [15]. Consistent with these ossification defects, we experienced in our cases, with variable degrees of severity, characteristic phenotypic features including translucent skin, soft skull, widely opened fontenelles and micromelia with limb deformities, along with radiologic anomalies encompassing diffuse decreased bone mineralization, fractured ribs, short and stocky long bones, platyspondyly and hypoplastic scapulae and iliac bones.
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.