Regulatory effect of miRNA enfolded in microparticles on endothelial cells

Endothelial cells are the cells lining the inner surfaces of blood vessels. They build up a single cell layer and play an important role in the regulation of vascular functions and the maintenance of homeostasis. The activation or injury of endothelial cells is associated with multiple diseases, including hypertension, atherosclerosis, cancer, diabetes, etc. Recent studies have found that microparticles are involved in the process of endothelial cell injury, thus playing a part in the development of many diseases. miRNAs enfolded in the microparticles have become importance in recent years. Moreover, recent studies also found that the concentration of the miRNAs enfolded in the microvesicles is higher than that of the miRNAs in the plasma, which means that the microparticles are the main form of miRNAs present in peripheral circulatory system. This article is to review the recent research progress in microparticle-encapsulated miRNAs and their regulatory effect on endothelial cell injury.     

The vascular endothelial progenitor cells and angiogenesis in ischemic cardiovascular diseases

The vascular endothelial progenitor cells are a population of functional endothelial precursors in circulating blood, which are derived from bone marrow or cord blood. CD34⁺, Flk-1⁺ and ACl33⁺ are their molecular markers. In this review, the functional characterization of vascular endothelial progenitor cells is introduced and the relationship between vascular endothelial progenitor cells and angiogenesis in is chemic cardiovascular diseases is discussed. These data may offer a foundation for the development of therapeutic angiogenesis for the prevention and treatment of ischemic cardiovascular diseases by transplantation of vascular endothelial progenitor cells.     

Current progress in structure and function of angiopoietin family

Angiopoietin family is a recently discovered type of cellular factors that specifically bind to the TIE-2 receptors located exclusively in endothelial cell membrane. The protein structures of this family members are similar. They can be structurally divided into three domains: an N-terminal region lacking homology to any known structures, an alpha-helical rich coiled-coil segment, and a fibrinogen-like domain. The distribution and biological activity of these factors are different in organism. Angiopoietin-1 as a agonist, mostly locates in close proximity with vascular endothelial cells, keeps the stability of blood vessels, enhances the affinity of vascular endothelial cells with surrounding cells and matrix, decreases the leakage of vessel. Ang-2 is a naturally occurring antagonist of Ang-1, exists in the angiogenic remodeling region and is related to the decrement of the stability of vessel. Ang-3 is widely distributed in multiple mouse tissues, while Ang-4 is expressed only in lung. Although Ang-3 and Ang-4 are structurally diverged from each other, they appear to represent the mouse and human counterparts of the same gene locus. Biological functions of Ang-3 and Ang-4 have not been elucidated yet. Angiopoietin family has potentially clinical applications for incurring illnesses which lead to vessel wound and vascular abnormal development.     

Mechanism of endothelial microparticle generation in hypertension and its pathophysiological roles

Hypertension is closely related to many target organ damage. Endothelial microparticles (EMPs), derived from endothelial cells in response to endothelial cell activation or apoptosis, are complex vesicular structures with a membrane skeleton and express various antigens specific to parental endothelial cells. EMPs circulate in human plasma and show elevated levels in many vascular damage diseases, such as hypertension, atherosclerotic vascular diseases, sepsis and diabetes. Recent studies have shown that EMPs could be a comprehensive index for endothelial homeostasis monitoring, such as vasomotor activity, anti-inflammatory status and so on. Especially, more and more evidence suggests that EMPs play an important role in hypertension. Patients with hypertension show higher circulating levels of EMPs compared with healthy controls. Furthermore, increasing evidence demonstrates that EMPs can induce endothelial dysfunction in vitro and in vivo, and then further promote the development of hypertension and its complications. This review will summarize the progress in the definition and formation mechanisms of EMPs, levels of EMPs and their phenotypes in patients with hypertension, and the pathophysiological roles of EMPs in hypertension.     

Effects of fluctuant high blood glucose on apoptosis in glomerular endothelial cells and renal tubular epithelial cells in diabetic rats

AIM:To explore the effects of fluctuant high blood glucose and stable high blood glucose on apoptosis and the expression of Bax and Bcl-2 in glomerular endothelial cells and renal tubular epithelial cells in diabetic rats. METHODS: 24 SD rats were divided into 3 groups: control group, stable high blood glucose group and fluctuant high blood glucose group. Diabetic rats were induced by intraperitoneal injection of STZ, and the fluctuant high blood glucose animal model was induced by intraperitoneal injection of aspart and glucose at different time points every day. Apoptosis was assessed by terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL), and immunohistochemistry was used to detect apoptosis associated gene bax and bcl-2 expression in kidney. RESULTS:After 4 experimental weeks, a significant increase in cell apoptosis, up-regulation of Bax protein expression in kidney tubular epithelial cell and down-regulation of Bcl-2 in glomerular endothelial cell in fluctuant high blood glucose rats were observed compared with stable high blood glucose rats.CONCLUSION: Fluctuant high blood glucose induces more apoptosis in renal tubular epithelial cells than that in stable high blood glucose diabetic rats.     

Effect of shikonin on high glucose-induced apoptosis and oxidative stress in vascular endothelial cells

AIM:To investigate the effect of shikonin on the apoptosis and oxidative stress induced by high concentration of glucose in vascular endothelial cells. METHODS:Rat thoracic aortic endothelial cells were randomly divided into 5 groups:normal control group (with glucose at concentration of 5.5 mmol/L in cell culture medium), high glucose group (with glucose at concentration of 33 mmol/L in cell culture medium), high glucose+low shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 0.1 μmol/L in cell culture medium), high glucose+medium shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 1 μmol/L in cell culture medium), and high glucose+high shikonin group (with glucose at concentration of 33 mmol/L and shikonin at concentration of 10 μmol/L in cell culture medium). After treatments, the cell viability was measured by CCK-8 assay and cell apoptotic rate was analyzed by flow cytometry. In addition, the status of oxidative stress was evaluated by determining the levels of malondialdehyde (MDA), reactive oxygen species (ROS), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). The activation of Nrf2/HO-1 signaling pathway was determined by Western blot. RESULTS:Compared with high glucose group, shikonin reversed high glucose-induced decrease in cell viability and increase in apoptosis in a concentration-dependent manner. High concentration of glucose induced high levels of MDA and ROS, while decreased the levels of SOD and GSH-Px. However, after treatment with shikonin, the contents of MDA and ROS were decreased, while the activities of SOD and GSH-Px were increased as compared with high glucose group. Furthermore, the high concentration of glucose up-regulated the protein levels of cleaved caspase-3, HO-1 and Nrf2 (nuclear). Compared with high glucose group, the protein levels of cleaved caspase-3, HO-1 and Nrf2 (nuclear) were partly decreased after treatment with shikonin. CONCLUSION:Shikonin alleviates high glucose-induced vascular endothelial cell apoptosis. Its mechanism may be related to activation of Nrf2/HO-1 signaling pathway and down-regulation of oxidative stress in vascular endothelial cells.     

Significance of expression of Flt-4 in different histopathological grades of astrocytoma

AIM: To study the significance of expression of fms-like tyrosine kinase 4 (Flt-4) in different histopathological grades of astrocytoma. METHODS: The surgical specimens from 50 brain astrocytoma patients were stained immunohistochemically for examining Flt-4 and vascular endothelial growth factor (VEGF) expression. Intratumoral microvessel density (IMVD) was calculated by labeling the endothelial cells of the blood vessels within the tumor. RESULTS: Flt-4, VEGF expression were closely correlated with histopathological grades of astrocytoma. Flt-4 and VEGF expression were found in 52% (26/50), 60% (30/50) of tumors. A significant correlation was found between Flt-4 and VEGF expression (P<0.01). CONCLUSIONS: Flt-4 is presented in human brain astrocytoma. Flt-4 expression is mainly expressed in vascular endothelial cells and some tumor cells. Flt-4 may not only come from autocrine secretion of vascular endothelial cells, but also from paracrine secretion of tumor cells. The expression of Flt-4 is significantly associated with histopathological grades of astrocytoma.     

Role of sphingosine 1-phosphate on high glucose-induced vascular endothelial cell dysfunction

AIM: To explore the role of sphingosine 1-phosphate (S1P) in the dysfunction of vascular endothelial cells exposed to high glucose. METHODS: In human aortic endothelial cells cultured under high-glucose (22 mmol/L glucose) medium, nitric oxide (NO) level, polymorphonuclear neutrophil-endothelial cell adhesion rate, protein level of intercellular adhesion molecule-1 (ICAM-1), migration of endothelial cells and Akt/endothelial nitric oxide synthase (eNOS) pathway activation were observed after S1P, sphingosine kinase-1 inhibitor and/or Akt inhibitor treatments. RESULTS: S1P decreased NO level, increased polymorphonuclear neutrophil adhesive rate, enhanced ICAM-1 protein level, and inhibited migration of endothelial cells and activation of Akt/eNOS pathway in endothelial cells cultured under high-glucose condition. Sphingosine kinase-1 inhibitor, which reduced S1P content, significantly improved the above endothelial cell function indexes and restored the activation of Akt/eNOS pathway. CONCLUSION: S1P promoted high glucose-induced dysfunction of endothelial cells probably by inhibiting the activation of Akt/eNOS signal pathway. Targeting S1P is expected to become one of potential treatment strategies to reduce endothelial cell dysfunction.     

VEGF promotes biliary epithelial cell viability and cystic dilation in rats with polycystic kidney

AIM:To explore the promoting effect of vascular endothelial growth factor (VEGF) on the viability of biliary epithelial cells and biliary cystic dilation in rats with polycystic kidney (PCK). METHODS:Immunohistoche-mical staining was used to detect the expression of VEGF (n=6) and CD31 (n=10) in the liver tissue of normal and PCK rats. RT-qPCR and ELISA were used to evaluate the expression levels of VEGF in rat biliary epithelial cells and culture supernatant. WST-1 assay was applied to measure the effect of VEGF on the viability of rat biliary epithelial cells, and the influence of cholangiocyte culture supernatant on the viability of rat vascular endothelial cells. The cell migration assay was employed to observe the effect of cholangiocyte culture supernatant on endothelial cell migration. Tube formation assay was used to assess the impact of cholangiocyte culture supernatant on the angiogenic ability of endothelial cells. RESULTS:The result of immunohistochemical staining manifested that VEGF was highly expressed in the cholangiocytes of the PCK rats (P<0.01). More newly formed blood vessels were observed in the hepatic portal area of PCK rats than that in normal rats (P<0.01). The results of RT-qPCR and ELISA suggested that the mRNA and protein expression levels of VEGF in the cholangiocytes of PCK rats were significantly higher than those in normal rats (P<0.01). VEGF enhanced the viability of cholangiocytes in PCK rats (P<0.01). The culture supernatant of cholangiocytes in PCK rats increased the endothelial cell viability (P<0.01). VEGF siRNA and VEGF receptor inhibitor reduced the viability of cholangiocytes (P<0.01). The results of cell migration assay and tube formation assay indicated that the abilities of endothelial cell migration and tube formation were improved by the culture supernatant of cholangiocytes in PCK rats (P<0.01). CONCLUSION:The bile duct cystic dilation of PCK rats was related to the excessive secretion of VEGF in bile duct epithelial cells.     

GM-CSF induces human vascular endothelial cells to form vessel-like structure and the role of VEGF

AIM: To investigate the influence of GM-CSF on human vascular endothelial cells induced to form new blood vessels and the role of VEGF. METHODS: HUVECs were cultured by Matrigel to set up a stable angiogenesis system with the stimulating factors. The rhGM-CSF concentration-dependent and time-dependent effects and the role of VEGF165 were detected. CD34 was measured by immunochemical staining and numbers of vessel formation was calculated under microscopic observation. RESULTS: After treatment with rhGM-CSF at various concentrations and at different time points, the numbers of vessel formation increased in a dose-dependent and time-dependent manner. In the presence of VEGF165, the numbers of vessel formation increased evidently. CONCLUSION: HUVECs were induced to develop tubular structure in vitro cultured with Matrigel. GM-CSF promotes human vascular endothelial cells to form vessel-like structure in vitro in a dose-dependent and time-dependent manner. VEGF also in vitro promotes human vascular endothelial cells to form new vessel-like structure.     

The intermediate phenotype of vascular smooth muscle cells in adult

The intermediate phenotype of vascular smooth muscle cell in adult is the dedifferentiation state returned from the high differentiation state, appeared on the damaged blood vessels.It is regulated by many factors.Its distribution, the characteristics of morphology and structure, the regulated transform factors and the molecular biological mechanism are introduced, and its functional significance and the role in vascular diseases are also discussed in this article.     

Structure,function and signal transduction of vascular endothelial growth factor receptor-2

Angiogenesis, or the formation of new blood vessels out of pre-existing capillaries, is very important in many physiologic and pathologic processes, such as embryonic development, cancer, retinopathies, etc. Vascular endothelial growth factor receptor-2 (VEGFR-2) plays a key role in angiogenesis. In this review, we discussed the structure, function and signal transduction of vascular endothelial growth factor receptor-2. Understanding these should provide important insights into how new strategies can be devised to interfere in the physiologic and pathologic processes involved in angiogensis.     

Effects of sesamin on blood fat,blood glucose and vascular remodeling in rats fed with high-fat and refined-sugar diet

AIM: To explore the effect of sesamin on blood fat, blood glucose and vascular remodeling in rats fed with high-fat, refined-sugar diet. METHODS: A high-fat, refined-sugar diet was given to rats for 24 weeks. Sesamin (120, 60, 30 mg·kg-1·d-1) was given by intragastric administration to the rats at 9th week, which lasted for 16 weeks. After 24 weeks, blood glucose, blood fat, blood pressure, activity of total anti-oxidation capacity (T-AOC) and concentration of hydrogen peroxide in serum and aorta were determined. Changes of histology and collagen fibers were observed in aorta by HE and Masson staining, respectively. Immunohistochemical method was used to examine iNOS protein expression in aorta. In mesenteric arteries, media thickness (M), luminal radius (L) and ratio of media to lumen (M/L) were measured. RESULTS: Compared to model group, sesamin (120, 60 mg·kg^-1·d^-1) obviously decreased the levels of blood glucose, blood fat, blood pressure and concentration of hydrogen peroxide in serum and aorta. Sesamin also markedly enhanced the activity of T-AOC in serum and aorta and reduced collagen deposition and iNOS protein expression in the vascular wall. In addition, proliferation of intima and vascular smooth muscle cells were improved. In mesenteric arteries, sesamin lessened M and M/L and increased L of mesenteric arteries. CONCLUSION: Sesamin ameliorates disorders of glucose and lipid metabolism and inhibits vascular remodeling in rats caused by chronic high-fat, refined-sugar diet.     

ceRNA mechanism of circRNA-miRNA-mRNA in atherosclerosis

Atherosclerosis (AS) is a common cardiovascular disease and a major cause of coronary heart di-sease, cerebral infarction and peripheral vascular disease. Circular RNA (circRNA) is a class of circularly closed non-co-ding RNAs that play an important role in the formation of AS. Physiological and pathological significances of the processes such as lipid metabolism, endothelial cell damage, vascular smooth muscle cell proliferation and migration, monocyte pha-gocytosis and foam-like cell formation, and inflammatory responses are involved in the development of AS. Most circRNA adjust mRNA expression by regulating microRNAs (miRNAs). circRNA provides new ideas and targets for the diagnosis and treatment of AS.     

The comparative study on SiNi-decoction and VitE against oxidative injury of vascular endothelial function and their preventive and therapeutic action on experimental atherosclerosis in rabbits

AIM: To compare effects of SiNi-decoction and Vitamin E on vascular endothelial function of experimental atherosclerosis rabbits and their therapeutic action on atherosclerosis.METHODS:The model of experimental atherosclerosis rabbits fed with forage of high lipid was established and treated in groups randomly. At the end of the experiment, samples of aorta and blood were taken and the percentage of lipid plaque area of aortic endothelium ,lipid metabolism and vascular endothelial oxidative injury (SOD activity, MDA content, NO level, endothelin concentration) of each group were analyzed. RESULTS: In comparison with model group,the percentage of the lipid plaque area of aortic endothelium and endothelial oxidative injury (except for SOD of VitE group) of SiNi-high and mid-dose group and VitE group are reduced obviously (P＜0.05),and the index of lipid metabolism of SiNi-decoction group is improved (P＜0.05). CONCLUSION:The comprehensive therapentic effects of SiNi decoction on vascular endothelial oxidative injury and atherosclerosis are superior to VitE.     

Preliminary study of endothelial progenitor cells formed vessel-like structure in vitro

AIM: Endothelial progenitor cells (EPCs) are a group of stem cells/progenitor cells, which exist in postnatal body and can be of specially homing to the foci of angiogenesis and then differentiate into endothelial cells.This investigation was to study the method for culturing endothelia progenitor cells (EPCs) in vitro, and to observe its feasibility and condition formed vessel-like structure.METHODS: The cells were isolated from born marrow, peripheral blood, umbilical cord blood or spleen in different laboratories.The EPCs derived from human umbilical cord blood and rabbit peripheral blood were cultured in vitro through adhesion selection and were differentiated into endothelial cells under the induction of special cytokines.The expression of CD34, VEGFR-2, AC133 and VE-cadherin were detected by fluorescence-activated cell sorting.The endothelial cell lineage was confirmed by DiI-ac-LDL up-taking and Ⅷ factor immunocy tochemistry.RESULTS: The EPCs derived from human umbilical cord blood and rabbit peripheral blood were cultured in vitro successfully, forming cord-like and tube-like structure.The EPCs derived from rabbit peripheral blood differentiated more mature and formed vessel-like structure.CONCLUSION: The EPCs derived from human umbilical cord blood and rabbit peripheral blood formed vessel-like structure in vitro.EPCs may be a potential resource of vessel tissue engineering.     

Alteration of pulmonary vascular structure and gaseous molecules in rats with pulmonary hypertension induced by high pulmonary blood flow

AIM: To examine the alteration of pathologic structure and gaseous molecules in rats with pulmonary hypertension induced by high pulmonary blood flow.METHODS: Aortocaval shunting was produced for 11 weeks in rats, and pulmonary hemodynamics was evaluated.Pulmonary vascular micro- and ultra- structure was also examined.Meanwhile,the concentration of plasma nitric oxide (NO) and carbon monoxide (CO) was measured by spectrophotometry.The expression of endothelial nitric oxide synthase (eNOS) and heme oxygenase-1 (HO-1) in pulmonary arteries was detected by immunohistochemistry.RESULTS: After 11- week aortocaval shunting,pulmonary artery mean pressure was significantly increased.Muscularization of small pulmonary vessels and relative medial thickness and area of pulmonary arteries were obviously increased in shunting rats compared with controls.Ultrastructure of intrapulmonary arteries changed obviously in shunting rats.Meanwhile,plasma NO concentration was increased and eNOS expression in pulmonary artery endothelial cells was significantly augmented in rats of shunting group.Plasma carbon monoxide level and HO-1 expression in puomonary artery smooth muscle cells,however,were not altered in shunting rats.CONCLUSIONS: Pulmonary vascular structural remodeling is the important pathologic basis of pulmonary hypertension induced by a left-to-right shunt,and NO other than CO might play an important regulating role in the development of high pulmonary blood flow-induced pulmonary hypertension.