Collagen is a kind of natural biomedical material and collagen based three-dimensional porous scaffolds have been widely used in skin tissue engineering. However, these scaffolds do not meet the requirements for artificial skin substitutes in terms of their poor mechanical properties, short supply, and rejection in the bodies. All of these factors limit their further application in skin tissue engineering. A variety of methods have been chosen to meliorate the situation, such as cross linking and blending other substance for improving mechanical properties. The highly biomimetic scaffolds either in structure or in function can be prepared through culturing cells and loading growth factors. To avoid the drawbacks of unsafety attributing to animals, investigators have fixed their eyes on the recombinant collagen. This paper reviews the the progress of research and application of collagen-based 3-dimensional porous scaffolds in skin tissue engineering.
ObjectiveTo investigate the changes of fibrinogen and classical markers of collagen metabolism [carboxy-terminal propeptide of type Ⅰ procollagen (PICP) and carboxy-terminal cross-linked peptide of type Ⅰ collagen (ICTP)] in peripheral blood and pericardial drainage after coronary artery bypass grafting (CABG) and/or heart valve replacement (VR), and to evaluate their relationship with postoperative atrial fibrillation (POAF) after cardiac surgery. MethodsPatients who underwent CABG and/or VR in the Heart Center of Beijing Chao-Yang Hospital from March to June 2021 were included. Peripheral blood and pericardial drainage fluid samples were collected before surgery and at 0 h, 6 h, 24 h and 48 h after surgery to detect PICP, ICTP and fibrinogen levels, and preoperative, intraoperative and postoperative confounding factors were also collected. PICP, ICTP and fibrinogen levels were measured by enzyme-linked immunosorbent assay (ELISA). ResultsA total of 26 patients with 125 blood samples and 78 drainage samples were collected. There were 18 males and 8 females with an average age of 64.04±7.27 years. The incidence rate of POAF was 34.6%. Among the factors, the fibrinogen level in pericardial drainage showed two peaks within 48 h after operation (0 hand 24 h after operation) in the POAF group, while it showed a continuous downward trend in the sinus rhythm (SR) group, and the change trend of fibrinogen in pericardial drainage was significantly different over time between the two groups (P=0.022). Fibrinogen in blood, PICP and ICTP in blood and drainage showed an overall decreasing trend, and their trends over time were not significantly different between the two groups of patients (P>0.05). Univariate analysis showed that fibrinogen at 24 h and 48 h after pericardial drainage, fibrinogen in preoperative blood, PICP immediately after surgery and right atrial long axis diameter were significantly higher or longer in the POAF group than those in the SR group. Multiple regression showed that fibrinogen≥11.47 ng/mL in pericardial drainage 24 h after surgery (OR=14.911, 95%CI 1.371-162.122, P=0.026), right atrial long axis diameter≥46 mm (OR=10.801, 95%CI 1.011-115.391, P=0.049) were independent predictors of POAF. ConclusionThis study finds the regularity of changes in fibrinogen and collagen metabolic markers after CABG and/or VR surgery, and to find that fibrinogen in pericardial drainage 24 h after surgery is a potential novel and predictive factor for POAF. The results provide a new idea for exploring the mechanism of POAF, and provide a research basis for the accurate prediction and prevention of clinical POAF.
ObjectiveTo investigate the effect of dust fine particles on tumor necrosis factor-α (TNF-α), matrix metalloproteinase (MMP), transforming growth factor-β1 (TGF-β1), and collagens in the lung tissue of rats.MethodsAccording to random number table method, 96 male Wistar rats were divided into an untreated control group, a treated control group and an experimental group, with 32 rats in each group. The experimental group was exposed to the wind tunnel simulation of sandstorm (5 days per week, 5 hours per day); the untreated control group was put in the standard living environment next to the wind tunnel; the treated control group was exposed to the same wind tunnel simulation of sandstorm for 5 hours every day, the speed of wind was the same as the experimental group, but without dust; On the 30th, 60th, 90th, and 120th day, the levels of TNF-α, MMP-2, MMP-9, TGF-β1, lung collagen type Ⅰ and Ⅲ in the lung tissue of rats were determined by enzyme linked immunosorbent assay.ResultsCompared with the untreated control group and the treated control group, the content of TNF-α was higher in the experimental group on 30th, 60th, 90th and 120th day (all P<0.05). The contents of MMP-9 and MMP-2 in the experimental group on 60th and 90th day were significantly higher than those in the untreated group and the treated control group, respectively (all P<0.05). On the 30th, 60th, 90th, and 120th day, the content of TGF-β1 in the experimental group was significantly higher compared with the two control groups (all P<0.05). The contents of lung collagen type Ⅰ and type Ⅲ were higher in the experimental group on 60th, 90th and 120th day, respectively, compared with the two control groups (all P<0.05).ConclusionsThe strong sandstorm environmental exposure to a certain period of time can promote lung interstitial collagen deposition in rat. With the prolonged exposure time, the deposition of collagen increases. TNF-α, MMP-2, MMP-9 and TGF-β1 may all participate and induce the process of pulmonary fibrosis.
Objective To review the lately new progress of fish collagen as biomedical materials, and then analyze feasibility and risk management of its application as a substitute of collagen originated from mammals in clinical practice. Methods Based on extensive research on new application and investigation of fish collagen, the paper was prepared to bring comprehensive analysis of its research and application status, and then several key points were focused on. Results Fish collagen has been proved to be a novel collagen of rich source, low risk of virus transmission, low biological risk, less religious barrier, and high biocompatibility. Fish collagen has promising prospect when applied in clinical practice as novel collagen especially as a substitute of collagen derived from mammals. However, very few related translational medicine research of fish collagen has been reported up to now in China. Conclusion As a novel potential substitute of collagen source derived from mammals, fish collagen is concerned to be clinical feasible and necessary in translational medicine. However, massive applied basic researches should be focused on in the further investigations.
Objective To develop a novel porous three-dimensional scaffold and to investigate its physico-chemical properties for tissue engineering cartilage.Methods Refined 88% deacetylation degree chitosan was prepared and dissolved in 0.2 mol/L acetate acid and fully mixed with highly purified porcine type Ⅱcollagen in 0.5 mol/L acetate acid solution in a ratio of 4 to 1 (wt/wt). Freeze-drying process was employed to fabricate the composite scaffold. The construct wascross-linked by use of 1-ethyl-3(3-dimethyl aminopropyl) carbodiimide (EDC) and Nhydroxysuccinimide (NHS). A mechanical tester was utilized to determine the tensilestrength change before and after cross-linking. The microstructure was observed via scanning electron microscopy (SEM). The lysozyme degradation was performedto evaluate the degradability of the scaffold in vitro. Results A bulk scaffold with desired configuration was obtained. The mechanical test showed that the crosslinking treatment could enhance the mechanical strength of the scaffold. The SEM results revealed that the two constituents evenly distributed in the scaffold and that the matrix was porous, sponge-like with interconnected pore sizing 100250 μm. In vitro lysozyme degradation indicated that crosslinked or uncross-linked composite scaffolds had faster degradation rate than the chitosan matrix. Conclusion Chitosan and typeⅡcollagen can be developed into a porous three-dimensional scaffold. The related physico-chemical tests suggest that the composite socaffold meets requirements for tissue engineered scaffold and may serve as an alternative cellcarrier for tissue engineering cartilage.
Objective To elucidate the role of the transcription factor liver activator protein (LAP, a member of the C/EBP family) in the expression of α1(I) collagen gene in activated hepatic stellate cells (HSCs). Methods Rat HSCs were prepared from SD rats by in situ perfusion and singlestep density Nycodenz gradient. Two chimeric luciferase reporter gene plasmids containing the human collagen α1(I) gene promoter fragments (-804～+1 452 or -804～+222) were constructed. Culture-activated HSCs were co-transfected with the reporter gene contructs and mammalian vector expressing LAP using the cationic-liposome mediated method, and the promoter activity was determined by measuring luciferase activity. Results The luciferase reporter gene construct containing the first intron of α1(I) collagen gene (-804～+1 452, was called as PGL3-col) had a higher level of gene expression, as compared with the construct lacking the first intron 〔was called as PGL3-col (△intron)-in activated HSCs (315±45 U/mg protein vs 220±70 U/mg protein, Ｐ＜0.05). Transient transfection of the vector expressing LAP significantly increased basal transcription from PGL3-col and PGL3-col (△intron) reporter gene vectors (587±62 U/mg protein vs 315±45 U/mg protein and 326±52 U/mg protein vs 220±70 U/mg protein respectively, both Ｐ＜0.05). Conclusion The transcription factor LAP transactivates collagen α1(I) gene in activated HSCs, and the first intron is important for α1(I) collagen gene transcription activity in activated HSCs.
Collagen (Coll), as the basic material of matrix scaffolds for cell growth, has been widely used in the field of tissue engineering and regenerative medicine. In this study, collagen protein was modified by L-lysine (Lys), and cross-linked by genipin (GN) to prepare the L-lysine-modified collagen (Lys-Coll-GN) scaffolds. Microstructure, pore size, porosity, stability and biocompatibility of Lys-Coll-GN scaffolds were observed. The results showed that the bond between L-lysine and collagen protein molecule was formed by generating amide linkage, and mouse embryo fibroblasts proliferation was not inhibited in the Lys-Coll-GN scaffolds. In the multiple comparisons of Coll-scaffolds, Coll-GNscaffolds and Lys-Coll-GN-scaffolds, Coll-scaffolds was the worst in mechanical characteristics while the highest in biodegradation rate. Compared to Coll-GN scaffolds, Lys-Coll-GN scaffolds had more fiber structure, higher interval porosity (P<0.01). Although the tensile stress of Lys-Coll-GN scaffolds reduced significantly, its elongation length extended when the scaffolds was fractured (P<0.01). The percentage of Lys-Coll-GN scaffolds residual weight was lower than that of Coll-GN-scaffolds after all the scaffolds were treated by collagenase for 5 days (P<0.01).This study suggested that Lys-Coll-GN scaffold had good biocompatibility, and it improved the mechanical property and degradation velocity for collagen-based scaffold. This study gave a new predominant type of tissue engineering scaffold for the regenerative medicine.
Objective To review the research progress of C terminal propeptide of collagen type II (CTX-II), a osteoarthritis (OA) biomarker. Methods Domestic and international l iterature about CTX-II was reviewed extensively and summarized. Results CTX-II is investigated broadly and has the best performance of all currently available biomarkers. CTX-II is a truly useful biomarker for early diagnosis, prognosis, and measurement of treatment response in OA. Conclusion Single CTX-II may be not sufficient for early diagnosis and prognosis of OA, so a combination of CTX-II and other biomarkers or diagnosis methods is needed.
Objective To study the influence of transforming growth factor-β1(TGF-β1), dentin non-collagen proteins(dNCPs) and their complexon tissue engineering pulp system. Methods Collagen I and dentin powder were used to construct the system of pulp cells in 3dimensional culture, dentin powder was added in the gel. The tissue engineering pulp were divided TGF-β1 group, dNCPs group, TGF-β1/dNCPsgroup and control group.After3, 6 and 14 days, the appearance and the differentiation of pulp cells were observed by HE staining and immunohistochemical staining -respectively. Results Collagen I could form netted collagen gel construction. Growing condition of pulp cells in gel was similar to that of pulp cells in vivo. After the TGF-β1 and dNCPswere added, the pulp cells had some characteristics of odontoblasts and had unilateral cell process after culture 6 days. Pulp cells arranged with parallel columnar and form dentin-pulp-like complex after 14 days. Immunohistochemical staining showed dentin salivary protein(DSP) began to express in some cells.The number of positive cell was most in the TGF-β1 group. No positive cells were detected in the control group. Conclusion The transforming growth factor-β1 and noncollagen proteins can stimulate the pulp cells to transform into odontoblasts to some extent, which promote the formation of tissue engineering pulp.
The aim of this paper is to explore the prevention of rabbit postoperative abdominal cavity adhesion with poly (lactic-co-glycotic acid) (PLGA) membrane and the mechanism of this prevention function. Sixty-six Japanese white rabbits were randomly divided into normal control group, model control group and PLGA membrane group. The rabbits were treated with multifactor methods to establish the postoperative abdominal cavity adhesion models except for those in the normal control group. PLGA membrane was used to cover the wounds of rabbits in the PLGA membrane group and nothing covered the wounds of rabbits in the model control group. The hematologic parameters, liver and kidney functions and fibrinogen contents were detected at different time. The rabbit were sacrificed 1, 2, 4, 6, 12 weeks after the operations, respectively. The adhesions were graded blindly, and Masson staining and immunohistochemistry methods were used to observe the proliferation of collagen fiber and the expression of transforming growth factorβ1 (TGF-β1) on the cecal tissues, respectively. The grade of abdominal cavity adhesion showed that the PLGA membrane-treated group was significant lower than that in the model control group, and it has no influence on liver and kidney function and hematologic parameters. But the fibrinogen content and the number of white blood cell in the PLGA membrane group were significant lower than those of model control group1 week and 2 weeks after operation, respectively. The density of collagen fiber and optical density of TGF-β1 in the PLGA membrane group were significant lower than those of model control group. The results demonstrated that PLGA membrane could be effective in preventing the abdominal adhesions in rabbits, and it was mostly involved in the reducing of fibrinogen exudation, and inhibited the proliferation of collagen fiber and over-expression of TGF-β1.