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.
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.
OBJECTIVE The effect of platelet-derived wound healing factor (PDWHF) on wound healing in diabetic rats was studied. METHODS Forty-four male SD rats were randomly divided into 2 groups. Thirty-two rats of experimental group accepted intraperitoneal injection of alloxan (1.5 mg/10 g body weight). Within one or two days after injection, while the blood sugar of the rats was higher than 180 mg/dl, the animal model of diabetic rat should have been established. Then a dorsal incision was given to every rat. After the addition of PDWHF (the experimental group) or bovine albumin (the control group), the incision was sutured up. Seven, ten and fourteen days after operation, the breaking strength of the wound was measured. On another hand, specimen from the wound was taken for the culture of fibroblasts. When the cultured fibroblasts have been incubated with 10% PDWHF for 4, 8 and 12 hours, the procollagen I (alpha 1) mRNA levels were examined respectively, and compared with those of control. RESULTS Significant difference in wound breaking strength had been observed between PDWHF-treated incisions and the control on 7, 10 and 14 days after wounding (P lt; 0.01). Experiment in vitro demonstrated that the procollagen I (alpha 1) mRNA levels in wound fibroblasts incubated with 10% PDWHF for 4, 8 and 12 hours were 0.9, 3.7 and 2.2 folds higher than those in fibroblasts in control. CONCLUSION It was suggested that direct stimulation of procollagen I (alpha 1) gene expression was one of the ways that PDWHF played its role in accelerating wound healing.
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 investigate the effects of basic fibroblast growth factor (bFGF) on the promoter activities of human alpha 1(I) procollagen gene and the interaction between bFGF and transforming growth factor-beta 1 (TGF-beta 1). METHODS: Fibroblasts of the hypertrophic scar and normal skin from a 3-year-old patient were primarily cultured and subcultured in vitro. Both of the fibroblasts were transient transfected with phCOL 2.5, containing -2.5 kb of 5’f lank sequence of human alpha 1(I) procollagen gene and CAT reporter gene by FuGENE transfection reagent; and treated thereafter by 16 ng/ml bFGF, 2 ng/ml TGF-beta 1 and 16 ng/ml bFGF + 2 ng/ml TGF beta 1 for 24 hours. The relative CAT expression values were determined by CAT-ELISA. RESULTS: TGF-beta 1 bly induced the CAT expression level, however, bFGF not only inhibited the basal CAT expression but also reduced the CAT expression up-regulated by TGF-beta 1 in normal skin and hypertrophic scar fibroblasts (P lt; 0.05). CONCLUSION: bFGF can reduce the promoter activities of human alpha 1(I) procollagen gene and antagonize the role of TGF-beta 1 in up-regulating the promoter activities of human alpha 1(I) procollagen gene in normal skin and hyertrophic scar fibroblasts.
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.
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 explore the effect of cyclopamine （Cyc） which is the inhibitor of the Hedgehog signaling pathway on portal venous pressure of normal and liver cirrhosis rats, and it’s possible mechanisms. Moreover, to provide the experimental basis of drug efficacy and clinical treatment. Methods Thirty two healthy male SD rats were randomly average divided into four groups：normal control group, normal treatment group, liver cirrhosis control group, and liver cirrhosis treatment group. The liver cirrhosis models of rat were established by using the thioacetamide （TAA） method, which made 0.03% of TAA as the initial water concentration, and then the concentration of TAA in drinking water was adjusted according to the changes of the weekly body weight of rats lasting for twelve weeks. In thirteenth week, intraperitoneal injection of corn oil （0.1 ml/100 g body weight, 1 time/d） were performed lasting for a week in rats of the normal control group and liver cirrhosis control group; intraperitoneal injection of Cyc 〔1 mg （0.1 ml）/100 g body weight, 1 time/d〕were performed lasting for a week in rats of the normal treatment group and liver cirrhosis treatment group. In fourteenth week, the liver function, portal venous pressure （PVP）, and the ration of liver or spleen weight to body weight were detected, the expressions of α-smooth muscle actin （α-SMA） and typeⅠcollagen α1 （Col1α1） of hepatic stellate cell were detected by using immunohistochemistry. Results PVP were （10.7±0.9） and （12.3±1.3） cm H2O （1 cm H2O=0.098 kPa） in normal control group and normal treatment group, respectivly, the latter was higher than the former （t=-2.918，P=0.011）. PVP were （21.8±0.7） and （14.3±1.4） cm H2O in liver cirrhosis control group and liver cirrhosis treatment group, respectivly, the latter was lower than the former（t=13.602，P=0.000）. The expressions of α-SMA and Col1α1 in liver cirrhosis treatment group was lower than the liver cirrhosis control group. There were no significant difference of the liver function and ration of liver or spleen weight to body weight between the treatment group and the control group （P＞0.05）. Conclusion Cyclopamine could signally reduce the PVP of liver cirrhosis rats through reducing the expressions of α-SMA and Col1α1.
Objective To evaluate the effect of nano-hydroxyapatit e collagen (nHAC) bone and marrow mesenchymal stem cells (MSCs) on the treatment of rabbit osteonecrosis of the femoral head (ONFH) defect. Methods From June to October 2004, animal models of ONFH defect were established i n 45 New Zealand rabbits. They were divided into 3 groups randomly:In group A, as the control group, defect was not filled with any implants; In group B with nHAC; In group C with nHAC+MSC. Imaging and histological observation were made 4, 8, 12 weeks after operation. Results group C had a better o steogenesis ability than group B and group A. group B had a better osteogenesis ability than group A. Obvious new bones and osteogenesis were observed in group C 4 weeks after operation. The defect areas in group C were almost repaired 12 weeks after operation. Conclusion nHAC has a better effect of o steoconduction and it is a superior material for repairing bone defect of ONFH a nd of great value in treating ONFH when compounded with MSCs.
Objective To investigate the effect of tissue engineering bone compounded in vitro by nanohydroxyapatite/collagen/ polylactic acid (nHAC/PLA) and recombinant human bone morphogenetic protein 2 (rhBMP-2) in repairing rabbit critical calvarial defects. Methods Forty eight New Zealand rabbits, weighting 2.0-2.5 kg, were made the models of critical cranial defects(15 mm in diameter) and divided into 4 groups randomly. Defects were repaired with autoflank bone in the positive control group; with no implant in the blank control group; with nHAC/PLA in the negative control; and with active nHAC/PLA(AnHAC/PLA) in the experimental group(the average quality of each AnHAC/PLA absorbed rhBMP-2 was 1.431 mg). The reapir results were observed through X-ray,HE dyeing and Masson’s trichrism dyeing after 8 and 16 weeks. Results The difference of bone formation was observed by X-ray block degree of skull defect area at 8 and 16 weeks. In the 8 th week and 16 th week, the radiopacities on cranial defect were 67.21%±2.06% and 86.48%±1.73% in the positive control group； 5.84%±1.92% and 9.48%±2.72% in the blank control group; 19.13%±2.51% and 35.67%±3.28% in the negative control group; and 58.84%±2.55% and 8561%±3.36% in the experimental group. There were significant differences between the negative control and the positive control group, and between the experimental group and the positive control group at 8 weeks(Plt;0.05) . There were significant differences between the negative control and blank group, and between the experiment and the blank group at 8 and 16 weeks(P＜0.05). The histology observation showed that the width of bone trabecula at 16 weeks was more than that at 8 weeks and bone defectwas full of bone tissue in positive control group. The bone defect was full of fibrous tissue at 8 and 16 weeks, and there was no new bone in the blank group. The bone defect was full of remnant material and fibrous tissue in the negative control group. The implanted area was replaced by the new bone at 8 weeks and the new bone was lamellar at 16 weeks in the experimental group; the residual material was less in defect area and there were more osteoblasts surrounding. Conclusion The nHAC/PLA is a good scaffoldmaterial of rhBMP-2 and AnHAC/PLA has agood ability in repairing bone defect. So it is hopeful to be applied in the clnical repair of large bone defect.