ObjectiveTo observe the effect of metformin on airway remodeling in asthma and its possible mechanism.MethodsTwenty-eight B/N rats were randomly divided into control group, asthma group, metformin intervention group and rapamycin intervention group. After that, the asthma model was established and intervened with metformin and rapamycin. The airway resistance and airway reactivity were measured 48 hours after the last challenge, and then the lung tissue samples were collected. Histopathological examination was used to observe airway inflammatory cell infiltration, goblet cell proliferation, airway wall fibrosis and remodeling, as well as airway smooth muscle proliferation. The expression of AMPK/mTOR pathway related proteins was detected by Western blot.ResultsCompared with the asthma group, metformin and rapamycin significantly reduced the airway responsiveness induced by high concentration of acetylcholine (P<0.05), reduced the infiltration of inflammatory cells in lung tissue and the changes of airway wall structure (P<0.05), reduced goblet cell proliferation in airway epithelium, collagen fiber deposition in lung tissue and bronchial smooth muscle hyperplasia (P<0.05). Further studies showed that the effects of metformin and rapamycin were related to AMPK/mTOR pathway. Compared with the asthma group, metformin and rapamycin could significantly reduce the expression of p-mTOR, p-p70s6k1 and SKP2, while p21 protein expression was significantly increased (P<0.05). In addition, metformin and rapamycin had similar effects (P>0.05).ConclusionMetformin can alleviate airway hyperresponsiveness and airway remodeling by activating AMPK and then inhibiting mTOR pathway, which may be a potential drug for treating asthma and preventing airway remodeling.
Bone remodeling requires an intimate cross-talk between osteoclasts and osteoblasts and is tightly coordinated with regulatory proteins that interact through complex autocrine/paracrine processes. Osteocytes, bone lining cells, osteomacs and vascular endothelial cells also regulate bone remodeling in the basic multicellular unit (BMU) via cell signaling networks of ligand-receptor complexes. In addition, through secreted and membrane-bound factors in the bone microenvironment, T and B lymphocytes mediate bone homeostasis for osteoimmunology. Osteoporosis and other bone diseases occur because multicellular communication within the BMU is disrupted. This review focuses on the roles of the cells in the BMU and the interaction between these cells and the factors involved in regulating bone remodeling at the cellular level. Understanding the process of bone remodeling and related genes could help us to lay the foundation for drug development against bone diseases.
Valvular heart disease is a structural or functional disease of the heart due to rheumatic fever, congenital malformation, infection, or trauma, resulting in abnormal cardiac hemodynamics and ultimately heart failure. Implantation of artificial heart valves has become the main way to treat heart valvular disease. Because the structure of the artificial heart valve plays a key role in the stress distribution and hemodynamic performance of the valve and stent, the geometric configuration of the artificial heart valve is constantly updated and improved during its development from mechanical valve to biological valve, which closely mimics the geometric characteristics of the normal natural heart valve. This article sums up the design process of geometric configuration of artificial heart valves and the influence of geometric configuration on the central disc stress and durability of artificial heart valves, analyzes the important parameters of geometric modeling for artificial heart valves, and discusses the development of the corresponding modeling method, to provide reference and new ideas for the biomimetic optimization design of artificial valves.
Astronauts who are exposed to weightless environment in long-term spaceflight might encounter bone density and mass loss for the mechanical stimulus is smaller than normal value. This study built a three dimensional model of human femur to simulate the remodeling process of human femur during bed rest experiment based on finite element analysis (FEA). The remodeling parameters of this finite element model was validated after comparing experimental and numerical results. Then, the remodeling process of human femur in weightless environment was simulated, and the remodeling function of time was derived. The loading magnitude and loading cycle on human femur during weightless environment were increased to simulate the exercise against bone loss. Simulation results showed that increasing loading magnitude is more effective in diminishing bone loss than increasing loading cycles, which demonstrated that exercise of certain intensity could help resist bone loss during long-term spaceflight. At the end, this study simulated the bone recovery process after spaceflight. It was found that the bone absorption rate is larger than bone formation rate. We advise that astronauts should take exercise during spaceflight to resist bone loss.
Taking advantages of the sparsity or compressibility inherent in real world signals, compressed sensing (CS) can collect compressed data at the sampling rate much lower than that needed in Shannon’s theorem. The combination of CS and low rank modeling is used to medical imaging techniques to increase the scanning speed of cardiac magnetic resonance (CMR), alleviate the patients’ suffering and improve the images quality. The alternating direction method of multipliers (ADMM) algorithm is proposed for multiscale low rank matrix decomposition of CMR images. The algorithm performance is evaluated quantitatively by the peak signal to noise ratio (PSNR) and relative l2 norm error (RLNE), with the human visual system and the local region magnification as the qualitative comparison. Compared to L + S, kt FOCUSS, k-t SPARSE SENSE algorithms, experimental results demonstrate that the proposed algorithm can achieve the best performance indices, and maintain the most detail features and edge contours. The proposed algorithm can encourage the development of fast imaging techniques, and improve the diagnoses values of CMR in clinical applications.
Objective To investigate the effects of tissue inhibitor-3 of matrix metalloproteinases(TIMP-3) genetransfected vascular smooth muscle cells(VSMCs) transplantation on heart structure after acute myocardial infarction (AMI) in rats and to explore the potential mechanisms. Methods Sixty-one female Wistar rats were produced AMI models by ligating the descending left coronary artery. Fifty-four rats were survived and divided into 3 groups randomly(n=18): 0.5 ml PBS containing 1×106 TIMP-3 gene-transfected VSMCs(group A), 1×106 VSMCs(group B) or 0.5 ml PBS without cell(group C) were injected into the ischemic myocardium immediately. Ischemic myocardium samples were harvested at 1 weekafter operation. The heart structure was observed through the tissue morphologic examination. The activity of TIMP-3 gene-transfected VSMCs were measured by immunohistochemical method. Proteins of TIMP-3 and matrix metalloproteinase 9(MMP-9) were determined by Western blot. Results VSMCs were cultivated and had a high purity(98%). TIMP-3 gene was transfected into VSMCs successfully. One week after operation in groups A, B and C, the average percentage of infarction myocardium size 〖KG6〗and left ventricle free wal area were 28.73%±1.56%, 39.63%±1.84% and 46.32%±2.16% separately.Group A was significantly lower than groups B and C(P＜0.01), group B was significantly lower than group C(P＜0.01). In groups A, B and C the averageleft ventricle volume indexes were 5.27±0.21 mm3／g, 6.69±0.34 mm3／g and 9.67±0.88 mm3／g respectively. Group A was significantly smaller than groups B and C(P＜0.01), group B was significantly smaller than group C(P＜0.01). The immunohistochemical observation confirmed that the implanted VSMCs and TIMP-3 gene were survival in ischemic area. The protein content of TIMP-3 in ischemicmyocardium was significantly higher in group A (300 704.8±3 692.8) than in groups B and C(195 548.8±3 014.2，177 991.1±2 502.1)(P＜0.01), the protein content of MMP-9 in ischemic myocardium was significantly lower in group A(594 827.4±5 708.5) than in groups B and C(921 461.4±8 887.4，1 044 445.0±8 788.6)(P＜0.01). Conclusion Implanted TIMP3 gene transfected VSMCs in ischemic myocardium can conspicuously reduce the myocardium remodeling after AMI.
Objective To analyze the clinical effect of partial aortic root remodeling for root reconstruction on Stanford type A aortic dissection. Methods From January 2010 to December 2015, 30 patients (25 males, 5 females) underwent partial aortic root remodeling for root reconstruction on Stanford type A aortic dissection with involvement of aortic root. The range of age was from 27 to 72 years, and the mean age was 51.2±8.0 years. The proximal aortic dissection received partial aortic root remodeling, and the operation procedures included partial aortic root remodeling+ascending aortic replacement in 9 patients, partial aortic root remodeling+ascending aortic replacement+hemi-arch replacement in 6 patients, partial aortic root remodeling+ascending aortic replacement+Sun's procedure in 15 patients. The patients were followed up for 10 to 60 months with a mean of 37.9±3.2 months. Preoperative and postoperative degrees of aortic regurgitation were compared. Results All patients survived from the operation, and one patient died from severe pulmonary infection 15 days after operation. The overall survival rate was 96.7% (29/30). One patient died during the follow-up. Two patients underwent aortic valve replacement in the 12th and 15th postoperative month respectively because of severe aortic regurgitation (AI). Up to the last follow-up, trivial or no aortic regurgitation was demonstrated in 24 patients, but mild aortic regurgitation occurred in 2 patients. Conclusion The surgical treatment for aortic root pathology due to Stanford type A aortic dissection is challenging, and partial aortic root remodeling operations could restore valve durability and function, and obtains the early- and mid-term results.
【Abstract】 Objective To discuss the role of leukocyte activation and inflammatory processes in the disease of chronic venous insufficiency （CVI）. Methods The relevant literatures about the role of leukocyte activation and inflammatory reaction in CVI were reviewed. Results The role of inflammatory reaction in occurrence and development of venous diseases has been studied a lot in recent years. It was found that the leukocyte activation and inflammatory reaction are involved in the structural remodeling of venous valves and walls, leading to valvular incompetence and formation of varicose veins. Conclusion Leukocyte activation and inflammatory processes take important roles in the occurrence and progression of CVI.
Objective To observe the protective effects of simvastatin at different stages on monocrotaline (MCT) induced pulmonary arteral hypertension (PAH) in rats and evaluate the early preventive effect of simvastatin. Methods Twenty-four male SD rats were randomized into a control group, a PAH group, an early intervention group, and a late intervention group, with 6 rats in each group. The rats in the control group received intraperitoneal injection of normal saline (NS) on d0. The rats in the PAH group received one-off intraperitoneal injection of MCT (50 mg/kg) on d0. The rats in the early intervention group were pretreated with oral gavage of simvastatin (20 mg·kg–1·d–1)(d–7––1) before the intraperitoneal one-off injection of MCT (50 mg/kg, d0) and continued with oral gavage of simvastatin for 14 days (d1~14). The rats in the late intervention group received one-off intraperitoneal injection of MCT (50 mg/kg)(d0) and oral gavage of simvastatin (20 mg·kg–1·d–1) for the next 21 days (d15~35). Thirty-five days after the MCT injection (d36), mean pulmonary arterial pressure (mPAP) and right ventricular systolic pressure (RVSP) were measured by right heart catheter. Then the rats were sacrificed for separating the heart and lung, the right ventricular hypertrophy index (RVHI) and percentage of small pulmonary arteries media thickness (WT%), the inflammation score around the small pulmonary arterial were recorded. Results Compared with those in the PAH group, RVSP, mPAP, RVHI and WT% in two simvastatin interventiongroups got much better (P＜0.01), and the inflammation score around the small pulmonary arterial declined (P＜0.05). Compared with those in the late intervention group, RVSP, mPAP in the early intervention group improved (P＜0.05) and WT% decreased more significantly (P＜0.01). However RVHI and the inflammation score around the small pulmonary arterial were not different between two simvastatin intervention groups. Conclusions Both early intervention and late intervention with simvastatin can reduce RVSP, mPAP and WT% in MCT induced PAH rats. Compared with later intervention, early intervention can prevent PAH more remarkably.
Objective To study the intervention effect of ginkgo biloba extract（GBE） on airway and vascular remodeling in rat model of chronic obstructive pulmonary disease(COPD).Methods Forty wistar rats were randomly divided into group A，B，C and D.The rat model of COPD were established by intratracheally injection of lipopolysaccharide and exposure to cigarette smoke in groups B，C and D.Groups C and D were given intraperitoneally injection with 40 mg/kg GBE respectively from day1 to day14 and day29 to day42.Forty-three days later，the rats were sacrificed for lung pathological examination.Results Group B，C and D all showed pathological changes characteristic of COPD to different extent.The average area and standard number of alveoli showed significant difference between each groups（all Plt;0.01）.The structure of bronchiole walls in group C and D show mild changes.The ratio of bronchial smooth muscle thickness to bronchial wall thickness and bronchial wall area to bronchial area of group C and D showed significant difference when compared with group A and B（all Plt;0.01）.The vascular smooth muscle cell of group C and D had mild hyperplasia and the vascular wall had slightly thickened.The ratio of vascular smooth muscle thickness to vascular wall thickness and vascular wall area to vascular area in group C and D showed significant difference when compared with group A and B（all Plt;0.01）.Conclusion GBE has inhibitory effects on airway and vascular remodeling in rats model of COPD.