[Show abstract][Hide abstract] ABSTRACT: Endothelial dysfunction is the pathophysiological characteristic of pulmonary arterial hypertension (PAH). Some paracrine factors secreted by bone marrow-derived endothelial progenitor cells (BMEPCs) have the potential to strengthen endothelial integrity and function. This study investigated whether BMEPCs have the therapeutic potential to improve monocrotaline (MCT)-induced PAH via producing vasoprotective substances in a paracrine fashion.
Bone marrow-derived mononuclear cells were cultured for 7 days to yield BMEPCs. 24 hours or 3 weeks after exposure to BMEPCs in vitro or in vivo, the vascular reactivity, cyclooxygenase-2 (COX-2) expression, prostacyclin (PGI2) and cAMP release in isolated pulmonary arteries were examined respectively. Treatment with BMEPCs could improve the relaxation of pulmonary arteries in MCT-induced PAH and BMEPCs were grafted into the pulmonary bed. The COX-2/prostacyclin synthase (PGIS) and its progenies PGI2/cAMP were found to be significantly increased in BMEPCs treated pulmonary arteries, and this action was reversed by a selective COX-2 inhibitor, NS398. Moreover, the same effect was also observed in conditioned medium obtained from BMEPCs culture.
Implantation of BMEPCs effectively ameliorates MCT-induced PAH. Factors secreted in a paracrine fashion from BMEPCs promote vasoprotection by increasing the release of PGI2 and level of cAMP.
PLoS ONE 01/2013; 8(11):e79215. · 3.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Interleukin-1β (IL-1β) is a multifunctional proinflammatory cytokine upregulated in acute phase of heart ischemic disease. Controversial effects of IL-1β have been demonstrated on endothelial progenitor cells (EPCs) functional activity. The aim of this study was to investigate the in vitro effect of IL-1β on activity of human origin EPCs and the possible mechanism involved. EPCs were isolated from peripheral blood of healthy volunteers without cardiovascular risk factors and characterized. After ex vivo cultivation, EPCs were stimulated with a series of final concentrations (0, 0.1, 1, and 10 ng/ml) of IL-1β for 24 h. In some other experiments, EPCs were pretreated with 10 μM LY294002 (Akt inhibitor) for 30 min and then stimulated with 1 ng/ml IL-1β for 24 h. Cell proliferation, apoptosis, adhesion, and migration were determined, respectively, by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, annexin V/propidium iodide binding assay, adhesion assay, and transwell migration assay. In addition, the vascular endothelial vascular growth factor-A (VEGF-A) production has been examined using quantitative real-time RT-PCR and ELISA assay. Furthermore, the total and phosphorylation level of Akt was determined by Western blot. IL-1β significantly stimulated EPC proliferation, migration, and adhesion and upregulated the angiogenic growth factor VEGF-A at mRNA and protein level, while exerted no influence on cell apoptosis. However, pretreatment with LY294002 significantly diminished IL-1β-induced proliferation, migration, adhesion, and VEGF-A production. One nanogram per milliliter IL-1β for 15 min activated phosphorylation of Akt. These results suggest a potent role for IL-1β in upregulating EPCs functions. The phosphatidyl-inositol-3-kinase-Akt signaling pathway could be involved in the regulation of EPCs functions induced by IL-1β.
[Show abstract][Hide abstract] ABSTRACT: Diabetic hearts are vulnerable to ischemia/reperfusion (I/R) injury. Pretreatment with exogenous calcitonin gene-related peptide (CGRP) exerts a cardioprotective effect against myocardial I/R injury. Our previous study found that the CGRP level was decreased in diabetic hearts. This study aimed to investigate whether up-regulation of CGRP could reduce I/R injury in diabetic hearts.
Adenovirus encoding the CGRP gene (Ad-CGRP) was injected intramyocardially in mice with or without streptozotocin (STZ) treatment. Three days after injection, the hearts were subjected to in vivo and in vitro I/R. Myocardial infarct size, cardiac function, lactate dehydrogenase (LDH) level in plasma and effluents, and cell mitochondrial function were measured. After ischemia (30 min) and reperfusion (24h) in vivo, diabetes mellitus (DM) mice had greater myocardial infarct size than their nondiabetic counterparts, and released more LDH in plasma. However, CGRP gene transfer reduced myocardial infarct size and plasma LDH level in both non-DM and DM hearts. After 30 min global ischemia and 40 min reperfusion in vitro, the DM hearts demonstrated increased left ventricular end-diastolic pressure (LVEDP) and effluent LDH level, and decreased left ventricular developed pressure (LVDP), coronary flow (CF), as well as cell mitochondrial function, when compared with the non-DM hearts. Again, CGRP gene transfer could protect against I/R injury in both non-DM and DM hearts.
Adenovirus-mediated up-regulation of CGRP gene expression protects diabetic hearts against I/R injury.
International journal of cardiology 05/2011; 156(2):192-8. · 6.18 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The mevalonate pathway is an important metabolic pathway that plays a key role in multiple cellular processes. The aim of this study was to define whether the enzyme expression in mevalonate pathway changes during cardiovascular remodelling in spontaneously hypertensive rats (SHR).
Hearts and thoracic aortas were removed for the study of cardiovascular remodeling in SHR and Wistar-Kyoto rats (WKY). The protein expression of the enzymes in hearts, aortas and livers was analyzed by western blot. The histological measurements showed that the mass and the size of cardiomyocytes, the media thickness and the media cross-sectional area (MCSA) of the thoracic aorta were all increased in SHR since 3 weeks of age. In the heart, there was overexpression of some enzymes, including 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR), farnesyl diphosphate synthase (FDPS), and geranylgeranyltransferase type I (GGTase-I), and downregulation of squalene synthetase (SQS) in SHR since 3 weeks of age. In the aorta, besides similar expressions of HMGR, SQS, FDPS and GGTase-I as in the heart, there was upregulation of farnesyltransferase α at 16 and 25 weeks of age and of farnesyltransferase β in 25-weeks-old SHR. Western blot demonstrated overexpression of HMGR and downregulation of SQS in SHR livers at all ages tested.
The cardiovascular remodeling of SHR preceded the development of hypertension, and altered expression of several key enzymes in the mevalonate pathway may play a potential pathophysiological role in cardiovascular remodeling.