The early cardiac biological pacemaker studies were mostly around HCN channel, and how to build a biological pacemaker through the enhanced If current. In recent years, however, people found that the genes of Tbx3 could play an important role in the development of cardiac conduction system, especially in processes of the maturity of the sinoatrial node and maintenance of its function. And the Tbx3 can further optimize the biological pacemaker. Therefore, it could be a new therapeutic focus in biological pacemaker and treatment of cardiac conduction system disease. This paper summarizes some of the latest research progress of the Tbx3 in biological pacemaker in recent years. We hope that this review could provide theoretical basis for the clinical applications of Tbx3.
Arrhythmias, Cardiac ; genetics ; Biological Clocks ; Brugada Syndrome ; Cardiac Conduction System Disease ; Heart ; physiopathology ; Heart Conduction System ; abnormalities ; Humans ; Sinoatrial Node ; T-Box Domain Proteins ; genetics

Recent studies have demonstrated that endothelial-to-mesenchymal transition ( EndMT) plays a pivotal role in the cardiovascular system, spanning cardiovascular development through to cardiovascular diseases (CVD).In this review, we describe the common signaling mechanisms that promote EndMT participating in the pathological process of CVD, and we discuss how these in-tracellular cascades participate in crosstalk to integrate cues to reverse EndMT, which potentially may provide novel therapeutic oppor-tunities for CVD.

Objective To study the therapeutic effect of mobilization of autologous bone marrow stem cells by G-CSF on myocardial infarction in experimental rats. Methods Rat model were established by coronary ligation. Rat bone marrow stem cells were mobilized by G-CSF. The volume of CD34~+ cells in peripheral blood was examined 1 week after myocardial infarction by flow cytometry. The infiltration of CD34~+ cells in the infarct zones were detected by immunohistochemical methods. At 4 weeks after infarction, the size of the infarction area, capillary density and cardiac function were evaluated by means of HE and immunohistochemisty staining as well as hemodynamic measurements. Results After 1 week, the level of CD34~+ cells in the G-CSF group increased significantly compared with the control group and infiltration of CD34~+ monocytes were found in the junctional zones in the G-CSF group. After 4 weeks, the size of the infarction area was minimized in the treatment group. More angiogenesis and better cardiac function were found in the G-CSF group compared with the control group. Conclusion The therapy of mobilization of autologous bone marrow stem cells by G-CSF is effective in treatment of myocardial infarction in rat models.

BACKGROUND:The benefit of cell therapy may be partly due to the secretion of angiogenic and antiapoptotic growth factors.Whether amniotic fluid stem cells (AFS) could secrete some growth factors requires further studies.OBJECTIVE:To isolate and culture AFS cells,and explore the angiogenic or antiapoptotic effect of cytokines secreted by AFS on endothelial cells.DESIGN,TIME AND SETTING:A in vitro cytological experiment was performed at the Institute of Hypertensive Disease,First Affiliated Hospital,Nanchang University from December 2008 to June 2009.MATERIALS:Term amniotic fluid of ten samples,50 mL/case,was obtained following caesarean delivery.The umbilical vein was used to isolate endothelial cells.Written informed content was obtained from all women.METHODS:AFS isolated from human amniotic fluid was cultured and digested by trypsin at confluence of 80%.The third passage of cells at a density of 5×10~8/L were divided into two groups:hypoxia group:the cells were cultured in 2% O_2 + 5% CO_2 +93% N_2;normal group:the cells were cultured in 5% CO_2 + 95% air.Two groups were cultured at 37 ℃ for 24 hours.The supematant of two groups was collected.The second passage of human umbilical vein endothelial cells cultured in vitro was collected and seeded onto 12-well culture plate at a density of 2×10~4 cells/well,and divided into 3 groups:control group was cultured in 2 mL EBM-2 containing 5% fetal bovine serum (FBS);normal group was cultured in 1 mL EBM-2 containing 5% FBS and 1 mL AFS cell culture solution;hypoxia group was cultured in 1 mL EBM-2 containing 5% FBS and 1 mL hypoxia AFS cell culture solution for 3 days,followed by incubation with 10 μg/L tumor necrosis factor (TNF)-α.MAIN OUTCOME MEASURES:AFS surface phenotype was examined by flow cytometry;the secretion level and mRNA expression of vascular endothelial cell growth factor (VEGF) and hepatocyte growth factor (HGF) were examined by ELISA or RT-PCR.The proliferation and apoptotic rates of endothelial cells were examined.RESULTS:AFS cells were long fusiform-shaped and arranged radially after 7 days of culture.The third passage of AFS cells expressed CD29 and CD105 while did not express CD34.AFS cells of normal culture secreted VEGF and HGF;AFS cells of hypoxia condition significantly increased secrete of VEGF (P＜0.01),and VEGF mRNA expression was significantly upregulated (P＜0.05),while HGF and mRNA expression remained unchanged (P＞0.05).Compared with control group,the number of endothelial cells was significantly increased in normal and hypoxia AFS cell groups after 3 days of culture (P＜0.05).After cocultured with TNF-α for 24 hours,the apoptosis rates of endothelial cells in AFS-conditioned medium was significantly decreased (P ＜ 0.05),and the change degree of hypoxia AFS cell group was greater than normal AFS cell group (P ＜ 0.05).CONCLUSION:AFS can secrete cytokines such as VEGF and HGF.Moreover,it significantly promotes endothelial cells proliferation and inhibits apoptosis.Under hypoxia condition,the secretion of VEGF from AFS cells is increased,and the effects on endothelial cells proliferation and apeptosis are enhanced.

Objective To study the effect and possible role of recombinant human erythropoietin(rhEPO) on the proliferation and apoptosis of endothelial progenitor cells (EPCs) from patients with diabetic nephropathy (DN). Methods Various concentration of rhEPO was added to the culture system of EPCs from 20 DN patients (DN group) and 20 normal people (control group). MTT assays were used to detect the proliferative rate, Annexin V/PI stains to detect the apoptotic rate, and Western blot assays to detect the expression level of Akt protein kinase. Results Proliferative ability of EPCs from control group and DN group was improved when concentration of rhEPO was 0.3, 0.6 and 1.2 kU/L, and it was dose-dependent. The effect from the latter was more obvious. The apoptotic rate of DN group was lowered and the expression levels of Akt protein kinase were upregulated when the concentration of rhEPO was 1.2 kU/L, while this kind of effect was blocked after Wortmannin was added to the culture system. Conclusion rhEPO can improve the number and function of EPCs from both healthy volunteers and patients with DN. PI3K/Akt pathway may play an important role.

To isolate and culture adipose stromal cells (ASCs), and study the effect of cytokines secreted by ASCs on endothelial cells, human adipose tissue was digested with collagenase type I solution and ASCs were derived by culture. The cells surface phenotype was examined by flow cytometry. ELISA was used to detect the secretion of VEGF, HGF, SDF-1 alpha and RT-PCR was employed to detect the expression of their mRNA. Then the ASC medium was utilized to culture human umbilical vein endothelial cells ECV304. Cells were counted by hemacytometer to determine the proliferation and Annexin V/ PI was employed for the examination of the apoptosis rate of ECV304. ASCs were derived by culture and expressed CD34, CD105 while they did not express CD31 or CD45. ASCs secreted cytokines such as VEGF, HGF and SDF-1 alpha so the ASC medium could stimulate proliferation and counteract apoptosis of endothelial cells (P < 0.05). Bcl-2 mRNA was also found to be up-regulated in the endothelial cells. It is concluded that ASCs can secrete cytokines and has significant effect on the proliferation of endothelial cells and apoptosis.

AIM: This study aimed to observe the effects of high-glucose on proliferation and apoptosis of endothelial progenitor cells (EPCs) in type 2 diabetes mellitus patients, and tried to elucidate their possible role. METHODS: Various concentrations of glucose were added to the culture system of EPCs from 25 cases of type 2 diabetes mellitus patients (DM group) and 25 cases of healthy volunteers (control group). MTT assays were used to detect the proliferative rates. Annexin-V/PI stains were used to detect the apoptotic rates, and RT-PCR to detect the expression level of bcl-2 and bax. RESULTS: Proliferative activity of EPCs in both control group and DM group were attenuated when concentration of glucose was 33 mmol/L, while apoptotic rates increased. No significant change of proliferative rate and apoptotic rate of EPCs in DM group and control group in the presence of 5 mmol/L glucose was observed. The expression level of bax of EPCs in both DM group and control group increased while expression level of bcl-2 did not change much in the presence of 33 mmol/L glucose. CONCLUSION: High-glucose attenuates proliferative activity of EPCs and increases the apoptotic rate. Upregulation of bax may be its possible role.

Objective:To study the in vitro effect of adipose stromal stem cells(ASC) on phenotype and secretion of cytokines of allogenetic T lymphocytes,and to elucidate the possible roles of ASC for immunomodulation.Methods:ASC was isolated and cultured.The supernatant of ASC and ASC itself were co-cultured with allogenetic T lymphocytes.MTT assays were used to detect the proliferative rates of T cells.Annexin-Ⅴ/PI staining was used to detect apoptotic rates,and flow cytometry to detect the proportion of CD4+CD25+ cells.ELISA was used to detect the secretion of IL-10 and TGF-?1.Reverse transcription-polymerase chain reaction(RT-PCR) was used to detect the expressing level of Foxp3 gene.Results:The supernatant of ASC had no deep impact on the proliferation and apoptosis of T lymphocytes.ASC had the direct inhibitory effect on growth of T lymphocytes,while the stem cells did not affect apoptosis.Both the supernatant of ASC and ASC itself increased the proportion of CD4+CD25+ cells in T lymphocytes,and increasd the level of IL-10 and TGF-?1.They could also up-regulate expressing level of Foxp3 in T cells.Conclusion:ASC can affect the function of T lymphocytes via cell-to-cell contact and secretion of cytokines.By these ways ASC exhibits negative immunomodulation and plays an important role in inducing immune tolerance.

Objective To investigate the association between plasma lipoprotein (a) [LP (a)] concentra-tion and in-stent restenosis after coronary stent implantation. Methods 152 patients with successful elective coro-nary stont implantation and percutancous transluminal coronary angioplasty (PICA) undergoing foUow-up angiogra-phy were retrospectively analyzed. These patients were divided into restenosis group( n = 29) and no-restenosis group (n = 123 ). The serum LP (a) levels of all patients were also investigated. The general clinical data were analyzed. Multivariate logistic regression was used for statistical analysis. Results We compared the serum Lap (a) levels, smoking and diabet in the two groups, and there was a statisticaLly significant difference between the restenosis group and no-restenosis group(P<0.05). Multivariate logistic regression showed that the elevation of Lap (a) level re-mained as an independent predictor of restenosis (RR =2. 648,95% CI 1. 066-6. 575,P <0. 05). Other risk fac-tors,such as smoking(P =0.023) ,diabet(P =0. 036) and the type of stent(P = 0.011 ) were also correlated with restenosis. Conclusions High plasma LP (a) concentration is an independent predictor of stent restenosis after stent implantation.

To isolate and culture adipose stromal cells (ASCs), and study the effect of cytokines secreted by ASCs on endothelial cells, human adipose tissue was digested with collagenase type Ⅰ solution and ASCs were derived by culture. The cells surface phenotype was examined by flow cytometry. ELISA was used to detect the secretion of VEGF, HGF, SDF-1 α and RT-PCR was employed to detect the expression of their mRNA. Then the ASC medium was utilized to culture human umbilical vein endothelial cells ECV304. Cells were counted by hemacytometer to determine the proliferation and Annexin V/PI was employed for the examination of the apoptosis rate of ECV304. ASCs were derived by culture and expressed CD34, CD105 while they did not express CD31 or CD45. ASCs secreted cytokines such as VEGF, HGF and SDF-1 α so the ASC medium could stimulate proliferation and counteract apoptosis of endothelial cells (P＜0.05). Bcl-2 mRNA was also found to be up-regulated in the endothelial cells. It is concluded that ASCs can secrete cytokines and has significant effect on the proliferation of endothelial cells and apoptosis.