ObjectiveTo review the role of stem cell niches in maintaining cardiac stem cells homeostasis, and to foresee its prospects. MethodsThe literature on cardiac stem cells niches was extensively reviewed. The roles of stem cell niches components, extracellular matrix, and secretory factors in maintaining cardiac stem cell homeostasis were analysed and reviewed. ResultsLots of experiments reveal that stem cell niches are able to delay the aging of cardiac stem cells, protect from external damage, keep stem properties, and improve the purity and quantity. However, the mechanism is not fully understood. ConclusionThe stem cell niches have a very bright application prospect in homeostasis, purification, and amplification for the cardiac stem cells, and it needs further study.
ObjectiveTo construct tumor specific tubercle bacillus antigen Ag85A gene lentiviral vector driven by murine telomerase catalytic subunit promoter (PmTERT), paving the way for further research in tumor targeting immuno-gene therapy. MethodsPmTERT was amplified by PCR method, with murine genomic DNA as template. Then, transcriptional activities of PmTERT in various murine and human cell strains were studied by luciferase assay. Ag85A expression lentiviral vectors driven by cytomegalo virus (CMV) promoter and PmTERT respectively (pLVX-Ag85ACMV and pLVX-Ag85A-PmTERT) were constructed with nucleic acid cloning approach. And above recombinants were verified with DNA sequencing and Western blot. ResultsLucifease assay revealed that 331 bp PmTERT cloned in present research had transcriptional activity in murine Lewis lung cancer cells, human lung adenocarcinoma cells A549, and human esophageal cancer cells EC-109, while no transcriptional activity in murine fibroblasts NIH3T3 and human embryo fibroblasts MRC-5. Western blot revealed expression of Ag85A in pLVX-Ag85A-CMV transfected Lewis and NIH3T3 cells, pLVX-Ag85A-PmTERT transfected Lewis cells, no expression in pLVX-Ag85A-PmTERT transfected NIH3T3 cells. ConclusionPmTERT has tumor specific transcriptional activity. Ag85A gene can express selectively in tumor cells, driven by PmTERT.
ObjectiveThrough comparing the efficacy of levosimendan with dopamine for severe valvular disease patients with atrial fibrillation surgery to explore the efficacy and safety of levosimendan used in cardiac surgery. MethodsWe allocated 48 severe valvular disease patients with atrial fibrillation surgery into a dopamine group (24 patients with 15 males and 9 females at age of 55.0 ± 17.4 years) and a levosimendan group (24 patients with 18 males and 6 females at age of 52.3 ± 16.2 years) by random digital table in the Affiliated Hospital of Luzhou Medical College between February and June 2014. The effects of the two groups were compared. ResultsHospitalization time (18.7±8.6 d vs 20.6±7.5 d, t=11.52, P=0.02) and the incidence of acute kidney injury(1/24 vs 5/24, χ2=25.30, P=0.01) in the levosimendan group were lower than those in the dopamine group. There was no statistical difference between the two groups in other early clinical outcomes. At each postoperative time point, there was no statistical difference in creatine kinase isoenzyme (CK-MB) between the two groups. While 6 to 48 hours after operation, there were significant differences in cardiac troponin (cTnI) and brain natriuretic peptide(BNP) level between the two groups (P < 0.05). Five days after operation, the left ventricular ejection fraction(LVEF) in the levosimendan group was higher than that in the dopamine group with statistical difference. ConclusionLevosimendan used for severe valvular disease with atrial fibrillation surgery is safe and effective, and has certain myocardial protection and renal protection effect, while its mechanism still needs further study.
ObjectiveTo explore whether preoperative coronary angiography could increase the incidence of postoperative acute kidney injury for patients with valve replacement. MethodsA total of 638 patients underwent routine cardiac valve replacement in our hospital from January 2013 through September 2015. There were 118 patients with preoperative coronary angiography (a coronary angiography group), and 520 patients without coronary angiography (a non-coronary angiography group). Serum creatinine (Scr), urea nitrogen(Bun), brain natriuretic peptide (BNP), creatine kinase myocardial band (CK-MB), cardiac troponin I (cTnI) values were recorded at 4 time points:before surgery (T0), after surgery 12 h (T1), 24 h (T2), 48 h (T3). The number of patients with acute kidney injury at the time of 48 hours after surgery was recorded. ResultsScr values (91.6±37.7 μmol/L vs. 81.0±27.4 μmol/L, 84.9±23.6 μmol/L vs. 73.5±25.3 μmol/L) increased in the patients who did not undergo coronary angiography at the time of 24 hours and 48 hours after cardiac surgery compared with the patients with coronary angiography with statistical differences. While there was no statistical difference in the incidence of acute kidney injury between the two groups. The cardiac enzymes had no statistical difference between the two groups. ConclusionPreoperative coronary angiography does not increase the probability of postoperative acute kidney injury.
ObjectiveTo study microRNA (miRNA) involved in the regulation of sinus cell differentiation by comparing sinus node, atrial myocardium, and ventricular myocardium specific miRNA expression profile differences in Kunming mice. MethodsA total of 180 Kunming mice, aged 60-90 days and weighing 35-45 g, were selected without gender differences after the method of anatomical localization for sinus node had been confirmed by preliminary experiments in another 10 Kunming mice. All the sinus node, atrial myocardium, and ventricular myocardium tissue from 180 mice were dissected and frozen by liquid nitrogen. The structure of tissue was observed by HE staining. Total RNA were extracted and quality-controlled before hybridize with miRNA chip. The chips with miRNA were used to screen specific miRNAs; and correlation analysis of gene function was done. ResultsThe area of mice sinus node located at juncture of the superior vena cava and the right atrium junction with crista as its longitudinal axis, ranged 2.0 mm×1.5 mm×1.0 mm. HE staining showed the sinus cells were less, with no stripes, lightly stained cytoplasm, large and round nucleus, and there were much fibrous connective tissue around cells with a visible sinus node artery. The miRNA microarray results showed that compared with atrial myocardium and ventricular myocardium, there were 39 differentially expressed miRNAs in sinus node, including 12 up-regulated miRNAs and 27 down-regulated miRNAs. Based on the regulatory networks of differential miRNA and target gene, the regulatory miRNA was obtained. ConclusionThe differentially expressed miRNA in mice sinus node possibly may be involved in the regulation of sinus cell differentiation.
ObjectiveTo investigate whether Akt1 gene transfection mediated by recombinant lentivirus (LVs) in the bone marrow mesenchymal stem cells (BMSCs) could enhance the ability of hypoxia tolerance so as to provide a theoretical basis for improving the effectiveness of stem cells transplantation. MethodLVs was used as transfection vector, enhanced green fluorescent protein (EGFP) was used as markers to construct the pLVX-EGFP-3FLAG virus vector carrying the Akt1 gene. The 3rd generation BMSCs from 3-5 weeks old Sprague Dawley rats were transfected with pLVX-EGFP virus solution as group B and with pLVX-EGFP-3FLAG virus solution as group C; and untransfected BMSCs served as control group (group A). At 2-3 days after transfection, the expression of green fluorescent was observed by fluorescence microscope; and at 48 hours after transfection, Western blot method was used to detect the expression of Akt1 protein in groups B and C. BMSCs of groups B and C were given hypoxia intervention with 94%N2, 1%O2, and 5%CO2 for 0, 3, 6, 9, and 12 hours (group B1 and group C1) . The flow cytometry was used to analyze the cell apoptosis rate and cell death rate, and the MTT method to analyze the cell proliferation, and Western blot to detect the expression of apoptosis related gene Caspase-3. ResultsAfter transfection, obvious green fluorescence was observed in BMSCs under fluorescence microscopy in groups B and C, the transfection efficiency was about 60%. Akt1 expression of group C was significantly higher than that of group B (t=17.525, P=0.013) . The apoptosis rate and cell death rate of group B1 increased gradually with time, and difference was significant (P<0.05) . In group C1, the apoptosis rate and cell death rate decreased temporarily at 3 hours after hypoxia intervention, then increased gradually, and difference was significant (P<0.05) . The apoptosis rate and cell death rate of group C1 were significantly lower than those of group B1 at each time point (P<0.05) except at 0 hour. MTT assay showed that absorbance (A) values of groups B and C were significantly higher than those of groups B1 and C1 at each time point (P<0.05) ; the A value of group B was significantly lower than that of group C at each time point (P<0.05) . The A value of group B1 was significantly lower than that of group C1 at 6, 9, and 12 hours after hypoxia intervention (P<0.05) . Western blot results showed that the Caspase-3 expression of group C1 significantly reduced when compared with group B1 at each time point (P<0.05) . ConclusionsAkt1 gene transfection mediated by recombinant LVs could significantly improve hypoxia tolerance of BMSCs by inhibiting the apoptosis, which could provide new ideas for improving the effectiveness of stem cells transplantation.