Mechanoresponsive microRNAs are a type of miRNAs which are sensitive or responsive to mechanical strain applied to them, their expression levels were changed after mechanical loading, thus affecting the expression levels of mRNA and proteins they regulated. Up to now, some mechanoresponsive miRNAs have been discovered in physiological or pathological tissues or organs. However, these discoveries are usually limited, and they are not able to guide clinical practice well. According to this situation, this paper summarizes research findings of mechanoresponsive miRNAs, and provides directions for clinical practice and further researches.
ObjectiveTo review the current progresses in purification strategies, biological characters, and the uses in tissue engineering of urine-derived stem cells (USCs). MethodsRecent relevant publications on the USCs were extensively reviewed, analyzed, and summarized. ResultsUSCs, usually isolated by adherence screening method, are a population of mesenchymal stem cells (MSCs)-like somatic stem cells possessing robust self-renew and multi-potential differentiation ability. Combined with using appropriate biomaterials and biological molecules, USCs can be used as a good cell source for tissue engineering. ConclusionAn alluring prospect exists on the USCs-related research. Further studies are required to investigate the origin, individual differences, and the therapeutic values of USCs.
This study was to explore a better three-dimensional (3-D) culture method of chondrocyte. The interpenetrating network (IPN) gel beads were developed through a photo-cross linking reaction with mixed barium ions and calcium ions at the ratio of 5:5 with the methacrylic alginate (MA), which was a chemically conjugated alginate with methacrylic groups. The second generation of primary cartilage cells was encapsulated in the MA gel beads for three weeks. In the designated timing, HE stain, Alamar blue method and Scanning electron microscopic were used to determine the cartilage cells growth, proliferation and the cell distribution in the scaffolds, respectively. The expression of typeⅡcollagen was investigated by an immunohistochemistry assay and the glycosaminoglycan content was quantitatively evaluated with the spectrophotometry of 1, 9 dimethylene blue assay. Compared to the alginate control group, the deposition of glycosaminoglycan was significantly upregulated in IPN-MA gel beads with higher cell proliferation. The secretion of extracellular matrix and proliferation of chondrocyte in methacrylic alginate gel beads were higher than that in Alginate beads. Cells were able to attach, to grow well on the scaffolds under scanning electron microscopy. The result of immunohistochemistry staining of collagen typeⅡwas positive, confirming the maintenance of chondrocyte phenotype in methacrylic alginate gel beads. This study shows a great potential for three-dimensional culture of cartilage.
ObjectiveTo review the mechanisms of bioactive substances of mesenchymal stem cells-derived exosomes (MEX) in tissue repair and analyze the therapeutic values of MEX. MethodRecent relevant literature about MEX for tissue repair was extensively reviewed and analyzed. ResultsThe diameter of exosomes ranges from 30 to 100 nm which contain an abundance of bioactive substances, such as mRNA, microRNA, and protein. The majority of the exact bioactive substances in MEX, which are therapeutically beneficial to a wide range of diseases, are still unclear. ConclusionsBioactive substances contained in the MEX have repairing effect in tissue injury, which could provide a new insight for the clinical treatment of tissue damage. However, further studies are required to investigate the individual differences of MEX and the possible risk of accelerating cancer progression of MEX.
ObjectiveTo review the current progresses in purification strategies, biological characters, and functions of endothelial progenitor cells (EPCs) derived extracellular vesicles (EVs) (EPC-EVs). MethodsRecent relevant publications on the EPC-EVs were extensively reviewed, analyzed, and summarized. ResultsEPC-EVs are usually isolated by differential centrifugation and exhibit a homogenous pattern of spheroid particles with a diameter ranging from 60 to 160 nm under transmission electron microscopy. EPC-EVs are positive for cell-surface markers of EPCs (CD31, CD34, and CD133), and negative for markers of platelets (P-selectin and CD42b) and monocytes (CD14). Recent studies have shown the effectiveness of EPC-EVs in ischemic injuries, anti-Thy1 glomerulonephritis, and cardiomyocyte hypertrophy, and also shown their predictive role in cardio-cerebral-vascular diseases. ConclusionAn alluring prospect exists on the EPC-EVs-related research. Further studies are required to decipher the composition of EPC-EVs and their precise role in pathophysiological processes, and to investigate the molecular mechanisms for their targeting and function.
ObjectiveTo explore a new method of developing a pre-vascularized cell sheets. MethodsBone marrow mesenchymal stem cells (BMSCs) from 3-week-old Japanese white rabbits were harvested and cultured. Vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) were added into the culture medium to differentiate into endothelial like cells (ECs) from BMSCs (experimental group), and non-induced cells served as the control group. The cell morphology was observed; and the von Willebrand factor (vWF) and CD31 immunofluorescent staining was used to identify the induced BMSCs. The 2nd generation BMSCs were seeded on a cell culture dish at a cell density of 9×104cells/cm2 and cultured for 14 days to form a thick cell sheet, and ECs from BMSCs were then seeded on the BMSCs sheet at a cell density of 5×104 cells/cm2 to develop pre-vascularized cell sheets and cultured for 3, 7, and 14 days (group A); non-induced BMSCs sheet and only ECs from BMSCs were used as group B and group C, respectively. The CD31 immunofluorescent staining and histological analysis were performed to evaluate the pre-vascularized cell sheet. ResultsBMSCs changed from long fusiform to cobblestone-like morphology after induced by VEGF and bFGF. The expressions of CD31 and vWF were positive in experimental group, but were negative in control group, which suggested that BMSCs have the ability to differentiate into ECs under this condition. After the ECs were seeded on the BMSCs sheet, the ECs migrated and rearranged; intracellular vacuoles and networks were observed. Furthermore, immunofluorescent staining for CD31 also revealed a developing process of tube formation after the ECs were seeded on the BMSCs sheet. The histological evaluations indicated the microvessel lumen formed. However, no similar change was observed in groups B and C. ConclusionBMSCs have the ability to differentiate into ECs after induced by VEGF and bFGF. ECs from BMSCs can develop into vascular network constructs when seeded on the BMSCs sheet, which provides a new method for engineering pre-vascularized tissue construction.
ObjectiveTo evaluate the effect of rural alone-two-child policy (RAC policy) on zero population growth, high sex ratio at birth (SRB), and aging population in China. MethodsRural areas of cities which implement the RAC policy were included. Data from the fifth and the sixth population censes were used to analyze the variation of the total fertility rate (TFR), SRB, and the number of teenagers of every household (NTH) in context of different social and economic levels. ResultsThe implementation of RAC policy in rural areas with middle and upper social economic levels showed a long-term effect of increasing the TFR and decreasing the SRB. The implementation of rural girl policy mixed with RAC policy in areas with middle social economic level showed a long-term effect of decreasing the TFR and increasing the SRB; but the long-term effect in areas with low social economic level was uncertain. The NTHs were decreased in all included areas. According to the urban and rural birth preference, we made inferences that the implementation of alone-two-child policy in cities could result in the increase of TFR and the decrease of SRB. ConclusionThe long-term effect of RAC policy implemented in rural areas with middle social economic level could solve the problems of zero population growth and the high SRB, but the long-term effect of mixed policy implemented in rural areas with middle social economic level may aggravate the two problems above. The RAC policy cannot solve the aging population problem in rural area.
ObjectiveTo assess the efficacy and safety of low-(10 mg) and high-dose (20 mg) of recombinant tissue typeplasminogen activator (rt-PA) catheter-directed thrombolysis for lower limb ischemia by using meta-analysis. MethodsThe literatures of randomized clinical trials (RCT) concerning low-versus high-dose rt-PA catheter-directed thrombolysis for lower limb ischemia study were searched using the national and international electronic databases.The literatures were screened and quality evaluated according to the inclusion and exclusion criteria, and analyzed by using the Cochrane Center the RevMan 5.2 software. ResultsA total of 4 RCT studies, with a total of 360 patients (192 patients in low dose group and 168 patients in high-dose group) were included.No statistical difference were noted in low-versus high-dose group with regard to ankle-brachial index (RR=0.20, 95%CI=-0.43-0.02, P=0.07), 30 days amputation-free survival (RR=1.00, 95%CI=0.94-1.08, P=0.91), 6 months the probability of restenosis (RR=1.00, 95%CI=0.60-1.67, P=1.00), and the incidence of groin hematoma (< 5 cm, RR=1.24, 95%CI=0.56-2.77, P=0.59).But the incidence of bleeding and the incidence of stress ulcer in low-dose group were lower than those in high-dose group (RR=2.38, 95%CI=1.10-5.15, P=0.03;RR=2.49, 95%CI=1.21-5.13, P=0.01). ConclusionTwo doses of rt-PA treatment of limb ischemia similar efficacy, but the incidence of low-dose regimen of complications is significantly lower than the high dose regimen.
ObjectiveTo investigate the expression of tumor necrosis factor α(TNF-α ) in isolated rat heart at different time points after myocardial hypoxia/reoxygenation. MethodsThe isolated langendorff perfused rat heart model was established. Forty-eight SD rats were randomly divided into four groups: a sham group, hypoxia/reoxygenation groups including a H/R 0.5 h group, a 1 h group and a 2 h group. The heart rate(HR), the 1eft ventricular development pressure(LVDP), maximal rates of increase/decrease of the left ventricular pressure(±dp/dtmax) were continuously recorded. The concentrations of TNF-α and creatine kinase-MB(CK-MB) in myocardium, mRNA expression of TNF-α in myocardium were tested. Ultra structure of myocardium was observed under electron microscope. ResultsThe levels of LVDP, ±dp/dtmax, and HR of hypoxia/reoxygenation group were significantly lower than those in the sham group(P<0.05).The levels of TNF-α and CK-MB and the expressions of TNF-α at mRNA level in the hypoxia/reoxygenation group were higher than those in the sham group(P<0.05).There were significant differences in the above parameters among the H/R 0.5 h group, the 1 h group, the 2 h group(P<0.05).The concentrations of TNF-α and CK-MB, the mRNA expression of TNF-α were higher in the I/R 2 h group than those in the other two groups. ConclusionThe high expression of TNF-α in myocardium after myocardial hypoxia/reoxygenation in rats is related to the degree of myocardium damage and may lead to myocardial injury.
ObjectiveTo analyze the reason and prevention of late bioprosthetic heart valve thrombosis (LBVT). MethodsBioprosthetic heart valves were implanted in 580 patients between January 2001 and July 2013 in Changhai Hospital, and only found one case of LBVT (0.2%). Reoperation was performed for a 67-year-old male patient 3 years after bioprosthetic aortic valve replacement due to severe aortic valve stenosis. Retrospectively analyzed the clinical data and reviewed the literature between January 1989 and December 2013 in Pubmed. ResultsNo risk factor for thrombosis was revealed in this patient. Pathology revealed valve thrombosis and collagen and elastic fibers fragmentation and disruption in valve leaflets. In literature review, 20 articles and 47 cases were brought in. The morbidity of LBVT was 0.2%-1.0%. At least 18 patients had high risk factors, and 15 of the 18 patients discontinued anticoagulation after 3 months. However, at least 10 patients had no high risk factors. Forty-four of the 47 patients received stented porcine valve replacement, only one patient received stented bovine pericardial valve replacement. ConclusionsLBVT is a rare but serious complication after bioprosthetic valve replacement, the causes of which include the feature of the patients and the bioprosthetic valves. Bovine pericardial valves could be superior to porcine valves in preventing LBVT. Postoperative long-time aspirin therapy is recommended for patients without high risk factors. Patients with any high risk factors should prolong anticoagulation.