To determine whether the cardiovascular effect of 1,25(OH)(2)D is dependent on calcium and/or phosphorus, mice with targeted deletion of the 25(OH)D 1alpha-hydroxylase and their wild-type littermates were fed a normal diet or a diet to rescue the ambient serum calcium and phosphorus levels. Mice on the normal diet were treated daily with vehicle or 1,25(OH)(2)D(3) while mice on the rescue diet received vehicle, captopril or losartan. After four weeks the vehicle-treated knockout mice developed hypertension, cardiac hypertrophy and impaired cardiac function along with an up-regulation of the renin-angiotensin system in both renal and cardiac tissues. Although the serum calcium and phosphorus levels were normalized in knockout mice on the rescue diet, abnormalities in blood pressure, cardiac structure-function and the renin-angiotensin system remained. In contrast, 1,25(OH)(2)D(3) not only normalized serum calcium and phosphorus levels but also normalized blood pressure, cardiac structure-function and the renin-angiotensin system. Treatment of the knockout mice with either captopril or losartan normalized blood pressure and cardiac structure and function although renin expression remained elevated. This study shows that 1,25(OH)2D plays a protective role in the cardiovascular system by repressing the renin-angiotensin system independent of extracellular calcium or phosphorus.
Aim:To investigate the effect of ginsenoside Rg1 on the migration, adhesion, proliferation, and VEGF expression of endothelial progenitor cells (EPCs). Methods: EPCs were isolated from human peripheral blood and incubated with different concentrations of ginsenoside Rg1 (0.1, 0.5, 1.0, and 5.0 µmol/L) and vehicle controls. EPC migration was detected with a modified Boyden chamber assay. EPC adhesion was determined by counting adherent cells on fibronectin-coated culture dishes. EPC proliferation was analyzed with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. In vitro vasculogenesis was assayed using an in vitro vasculogenesis detection kit. A VEGF-ELISA kit was used to measure the amount of VEGF protein in the cell culture medium. Results: Ginsenoside Rg1 promoted EPC adhesion, proliferation, migration and in vitro vasculogenesis in a dose-and timedependent manner. Cell cycle analysis showed that 5.0 µmol/L of ginsenoside Rg1 significantly increased the EPC proliferative phase (S phase) and decreased the resting phase (G 0 /G 1 phase). Ginsenoside Rg1 increased vascular endothelial growth factor production.
Conclusion:The results indicate that ginsenoside Rg1 promotes proliferation, migration, adhesion and in vitro vasculogenesis.
PDGF-BB (Platelet-derived growth factor BB) and TGF-beta1(transforming growth factor beta1) are important growth factors in the modulation of vascular smooth muscle cell (VSMC) proliferation and PCNA (proliferating cell nuclear antigen) expression in VSMCs. PCNA expresses at a high level in proliferating cells. The present study aims to assess the effects of PDGF-BB-induced overexpression of TGF-beta1 on PCNA in VSMCs. The downstream proteins of the TGF-beta signalling system in VSMCs, including TGF-beta type I receptor (ALK-5 in VSMCs), Smurf2, Smad2, pSmad2/3, Smad4, and Smad7, were also investigated. Our results revealed that PDGF-BB significantly increased the expressions of TGF-beta1 and PCNA, and the increase in PCNA can be partially inhibited by neutralizing anti-TGF-beta1 antibody. Furthermore, PDGF-BB increased the expression of ALK-5, Smurf2, pSmad2/3, and Smad4, but lowered the levels of Smad2 and Smad7; these alterations were partially restored by neutralizing anti-TGF-beta1 antibody. These findings suggest that PDGF-BB promotes PCNA expression in VSMCs partially through TGF-beta1 overexpression, and that the TGF-beta signalling system involves the molecular mechanism of PDGF-BB in VSMCs.
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