Collagen, which widely exists in skin, bone, muscle and other tissues, is a major structural protein in mammalian extracellular matrix. It participates in cell proliferation, differentiation, migration and signal transmission, plays an important role in tissue support and repair and exerts a protective effect. Collagen is widely used in tissue engineering, clinical medicine, food industry, packaging materials, cosmetics and medical beauty due to its good biological characteristics. This paper reviews the biological characteristics of collagen and its application in bioengineering research and development in recent years. Finally, we prospect the future application of collagen as a biomimetic material.
Animals ; Collagen/analysis* ; Tissue Engineering/methods* ; Extracellular Matrix/metabolism* ; Biomimetic Materials/chemistry* ; Bone and Bones ; Tissue Scaffolds ; Mammals/metabolism*

Objective: To investigate the clinicopathologic features,diagnosis and prognosis of pericytic tumor of the kidney. Methods: Three cases of pericytic tumor of the kidney (two cases were diagnosed as glomangiomyomas and one case as pericytic tumor,unclassified) were collected from the affiliated Hospital of Qingdao University between January 2014 to May 2021; the clinical and morphologic features, immunohistochemical and molecular characteristics were analyzed and the relevant literature was reviewed. Results: The three patients included one male and two females, with ages ranging from 21 to 70 years. In two patients the tumors were detected incidentally at physical examination and one patient presented with low back discomfort. Imaging showed a rounded nodular soft tissue density shadow in renal parenchyma, and enhancement scan showed uneven delayed enhancement. Grossly, two tumors were located in the renal hilum and one in the renal parenchyma; all were nodular. The tumors were measured in size from 1.6 cm to 5.1 cm (mean 4.1 cm) and showed gray or gray-red cut surface. Histologic examination showed the tumor cells were arranged in solid sheets or small nodules, closely related to vascular wall. Tumor cells were mostly epithelial-like with abundant cytoplasm, light eosinophilia, obscure boundary and round nuclei with visible nucleoli. Vague bundles and fascicular arrangements of smooth muscle component were noted in some areas, with transition of both components. There was no necrosis. By immunohistochemistry, the tumor cells strongly and diffusely expressed vimentin, SMA and collagen Ⅳ, two cases expressed CD34, all three cases expressed PDGFRB to varying extent, and the Ki-67 index was 2%-3%. PCR tests showed absent K-RAS, BRAF V600E gene mutation in all three cases. PDGFRB mutations in exons 3 and 18, respectively were found in two of the three cases by high-throughput sequencing, and no NOTCH 1/2/3 gene fusions were found in any of them. Follow-up information (range: 6-92 months) showed no evidence of local recurrence or distant metastasis in all three patients. Conclusions: Pericytic tumor of the kidney is a rare mesenchymal tumor originating in the kidney with differentiation to smooth muscle, most commonly glomus tumor. The mild pleomorphism, close relationship with vascular wall and spindled smooth muscle components suggest the diagnosis of the tumor. Expression of both epithelial and muscle-associated markers aids the diagnosis. PDGFRB gene mutations may have an important role in the development of this tumor. Most patients have a good prognosis, and a few cases have malignant biological behavior.
Adult ; Aged ; Biomarkers, Tumor/analysis* ; Collagen ; Diagnosis, Differential ; Female ; Glomus Tumor/pathology* ; Humans ; Ki-67 Antigen ; Kidney/pathology* ; Kidney Neoplasms/pathology* ; Male ; Middle Aged ; Neoplasms, Connective and Soft Tissue ; Proto-Oncogene Proteins B-raf ; Receptor, Platelet-Derived Growth Factor beta ; Vimentin ; Young Adult

Thoracic aortic dissection (TAD) without familial clustering or syndromic features is known as sporadic TAD (STAD). So far, the genetic basis of STAD remains unknown. Whole exome sequencing was performed in 223 STAD patients and 414 healthy controls from the Chinese Han population (N = 637). After population structure and genetic relationship and ancestry analyses, we used the optimal sequence kernel association test to identify the candidate genes or variants of STAD. We found that COL3A1 was significantly relevant to STAD (P = 7.35 × 10
Aneurysm, Dissecting/genetics* ; Case-Control Studies ; Cluster Analysis ; Cohort Studies ; Collagen Type III/genetics* ; Computational Biology ; Genetic Predisposition to Disease ; Humans

China is the country with high incidence of high myopia in the world. High myopia can cause severe vision impairment. So far, there is no effective treatment for high myopia in clinic. Scleral collagen cross-linking surgery has been proven to be effective in preventing animal eye axial elongation
Animals ; Collagen ; Cross-Linking Reagents ; Finite Element Analysis ; Photosensitizing Agents ; Riboflavin ; Sclera

OBJECTIVE: To carry out genetic testing and prenatal diagnosis for a family affected with recessive dystrophic epidermolysis bullosa (RDEB). METHODS: All exons of the COL7A1 gene and their flanking regions were subjected to PCR and Sanger sequencing. Suspected variant was validated in family members, based on which prenatal diagnosis was provided. RESULTS: Sanger sequencing found that the proband has carried two variants of the COL7A1 gene, namely c.7289delC (p.Pro2430Glnfs*36) and c.7474C>T (p.Arg2492*), which were respectively derived from his mother and father. The same variants were not found among 100 healthy controls. By prenatal diagnosis, the fetus was found to have inherited the c.7474C>T (p.Arg2492*) variant from its father. CONCLUSION The pathogenic variants of the COL7A1 gene of the RDEB family were clarified, based on which prenatal diagnosis was provided.
Child ; Collagen Type VII ; genetics ; Epidermolysis Bullosa Dystrophica ; genetics ; Exons ; Female ; Genes, Recessive ; Genetic Testing ; Humans ; Male ; Mutation ; Pregnancy ; Prenatal Diagnosis ; Sequence Analysis, DNA

OBJECTIVES: This study investigated the indirect effect of calcium-enriched mixture (CEM) cement and mineral trioxide aggregate (MTA), as 2 calcium silicate-based hydraulic cements, on human dental pulp stem cells (hDPSCs) through different dentin thicknesses.MATERIALS AND METHODS: Two-chamber setups were designed to simulate indirect pulp capping (IPC). Human molars were sectioned to obtain 0.1-, 0.3-, and 0.5-mm-thick dentin discs, which were placed between the 2 chambers to simulate an IPC procedure. Then, MTA and CEM were applied on one side of the discs, while hDPSCs were cultured on the other side. After 2 weeks of incubation, the cells were removed, and cell proliferation, morphology, and attachment to the discs were evaluated under scanning electron microscopy (SEM). Energy-dispersive X-ray (EDXA) spectroscopy was performed for elemental analysis. Alkaline phosphatase (ALP) activity was assessed quantitatively. The data were analyzed using the Kruskal-Wallis and Mann-Whitney tests.RESULTS: SEM micrographs revealed elongated cells, collagen fibers, and calcified nucleations in all samples. EDXA verified that the calcified nucleations consisted of calcium phosphate. The largest calcifications were seen in the 0.1-mm-thick dentin subgroups. There was no significant difference in ALP activity across the CEM subgroups; however, ALP activity was significantly lower in the 0.1-mm-thick dentin subgroup than in the other MTA subgroups (p < 0.05).CONCLUSIONS: The employed capping biomaterials exerted biological activity on hDPSCs, as shown by cell proliferation, morphology, and attachment and calcific precipitations, through 0.1- to 0.5-mm-thick layers of dentin. In IPC, the bioactivity of these endodontic biomaterials is probably beneficial.
Alkaline Phosphatase ; Biocompatible Materials ; Calcium ; Cell Proliferation ; Collagen ; Dental Pulp Capping ; Dental Pulp ; Dentin ; Endodontics ; Humans ; Microscopy, Electron, Scanning ; Miners ; Molar ; Pemetrexed ; Spectrum Analysis ; Stem Cells

BACKGROUND: Nowadays, production of nanocomposite scaffolds based on natural biopolymer, bioceramic, and metal ions is a growing field of research due to the potential for bone tissue engineering applications. METHODS: In this study, a nanocomposite scaffold for bone tissue engineering was successfully prepared using collagen (COL), beta-tricalcium phosphate (β-TCP) and strontium oxide (SrO). A composition of β-TCP (4.9 g) was prepared by doping with SrO (0.05 g). Biocompatible porous nanocomposite scaffolds were prepared by freeze-drying in different formulations [COL, COL/β-TCP (1:2 w/w), and COL/β-TCP-Sr (1:2 w/w)] to be used as a provisional matrix or scaffold for bone tissue engineering. The nanoparticles were characterized by X-ray diffraction, Fourier transforms infrared spectroscopy and energy dispersive spectroscopy. Moreover, the prepared scaffolds were characterized by physicochemical properties, such as porosity, swelling ratio, biodegradation, mechanical properties, and biomineralization. RESULTS: All the scaffolds had a microporous structure with high porosity (~ 95–99%) and appropriate pore size (100–200 µm). COL/β-TCP-Sr scaffolds had the compressive modulus (213.44 ± 0.47 kPa) higher than that of COL/β-TCP (33.14 ± 1.77 kPa). In vitro cytocompatibility, cell attachment and alkaline phosphatase (ALP) activity studies performed using rat bone marrow mesenchymal stem cells. Addition of β-TCP-Sr to collagen scaffolds increased ALP activity by 1.33–1.79 and 2.92–4.57 folds after 7 and 14 days of culture, respectively. CONCLUSION: In summary, it was found that the incorporation of Sr into the collagen-β-TCP scaffolds has a great potential for bone tissue engineering applications.
Alkaline Phosphatase ; Animals ; Biopolymers ; Bone and Bones ; Bone Marrow ; Collagen ; Fourier Analysis ; Freeze Drying ; In Vitro Techniques ; Ions ; Mesenchymal Stromal Cells ; Nanocomposites ; Nanoparticles ; Porosity ; Rats ; Spectrum Analysis ; Strontium ; X-Ray Diffraction

Cardiovascular disease is the leading cause of morbidity and mortality worldwide. Early detection of subclinical atherosclerosis is important for reduction of cardiovascular risk. However, the current diagnostic strategy, which focuses on traditional risk factors or the use of risk scoring, is unsatisfactory. Arterial walls thicken and stiffen with age, a process known as arteriosclerosis. There is a close interaction between arterial stiffness and atherosclerosis. Increased luminal pressure and shear stress caused by arterial stiffening result in endothelial dysfunction, accelerate the formation of atheromas, and stimulate excessive collagen production and deposition in the arterial wall. Carotid intima-media thickness (CIMT) has been shown to predict cardiovascular risk in many large studies. However, there is controversy regarding the value of CIMT for prediction of cardiovascular risk because of differences in study design, specifically with respect to CIMT measurements. Pulse wave velocity (PWV) is the most widely used measure of arterial stiffness; measurement of PWV is simple, non-invasive, and reproducible. Many clinical studies and meta-analyses have shown that PWV has predictive value in cardiovascular disease beyond traditional risk factors, both in the general population and in patients with various diseases. Brachial pressure has been a poor surrogate for aortic pressure for more than 50 years. However, recent studies have shown a closer relationship between central blood pressure and intermediate cardiovascular phenotypes or cardiovascular target organ damage, compared to the respective relationships with brachial blood pressure. Considering the non-invasiveness and ability to collect multiple types of clinical data, measurement of CIMT, PWV, and central blood pressure may be useful to identify patients at high risk for development of cardiovascular disease.
Arterial Pressure ; Arteriosclerosis ; Atherosclerosis ; Blood Pressure ; Cardiovascular Diseases ; Carotid Intima-Media Thickness ; Collagen ; Humans ; Mortality ; Phenobarbital ; Phenotype ; Plaque, Atherosclerotic ; Pulse Wave Analysis ; Risk Factors ; Vascular Stiffness

This study aimed to obtain a recombinant human-source collagen for industrialization. First, based on the Gly-X-Y sequence of human type I collagen, we optimized the hydrophilic Gly-X-Y collagen peptide, designed the human collagen amino acid sequence and the corresponding nucleotide sequence. Next, the expression vector pPIC9K-COL was constructed via endonuclease digestion technology. We obtained an engineering strain of human-source collagen by electrotransforming Pichia pastoris, and then it was fermented, purified and identified. As a result, the expression level reached 4.5 g/L and the purity was over 95%. After amino acid N-terminal sequencing, molecular weight analysis, amino acid analysis and collagenase degradation test, we confirmed that the obtained collagen was consistent with designed primary structure of human-source collagen. After freeze-drying, we analyzed the collagen by scanning electron microscope and cell cytotoxicity, confirming that the collagen has porous fiber reticular structure and superior cytocompatibility. This indicates that human-source collagen has potential to be applied as biomedical material. In conclusion, we successfully obtained the expected human-source collagen and laid a foundation to its further application.
Amino Acid Sequence ; Biocompatible Materials ; Collagen ; analysis ; Freeze Drying ; Humans ; Pichia ; Recombinant Proteins

Novel hydrogel composed of both chondroitin sulfate (CS) and gelatin was developed for better cellular interaction through two step double crosslinking of N-(3-diethylpropyl)-N-ethylcarbodiimide hydrochloride (EDC) chemistries and then click chemistry. EDC chemistry was proceeded during grafting of amino acid dihydrazide (ADH) to carboxylic groups in CS and gelatin network in separate reactions, thus obtaining CS–ADH and gelatin–ADH, respectively. CS–acrylate and gelatin–TCEP was obtained through a second EDC chemistry of the unreacted free amines of CS–ADH and gelatin–ADH with acrylic acid and tri(carboxyethyl)phosphine (TCEP), respectively. In situ CS–gelatin hydrogel was obtained via click chemistry by simple mixing of aqueous solutions of both CS–acrylate and gelatin–TCEP. ATR-FTIR spectroscopy showed formation of the new chemical bonds between CS and gelatin in CS–gelatin hydrogel network. SEM demonstrated microporous structure of the hydrogel. Within serial precursor concentrations of the CS–gelatin hydrogels studied, they showed trends of the reaction rates of gelation, where the higher concentration, the quicker the gelation occurred. In vitro studies, including assessment of cell viability (live and dead assay), cytotoxicity, biocompatibility via direct contacts of the hydrogels with cells, as well as measurement of inflammatory responses, showed their excellent biocompatibility. Eventually, the test results verified a promising potency for further application of CS–gelatin hydrogel in many biomedical fields, including drug delivery and tissue engineering by mimicking extracellular matrix components of tissues such as collagen and CS in cartilage.
Amines ; Cartilage ; Cell Survival ; Chemistry ; Chondroitin Sulfates ; Chondroitin ; Click Chemistry ; Collagen ; Extracellular Matrix ; Gelatin ; Hydrogel ; Hydrogels ; In Vitro Techniques ; Spectrum Analysis ; Tissue Engineering ; Transplants