Neural Remodeling of the Left Atrium in Rats by Rosuvastatin Following Acute Myocardial Infarction.

OBJECTIVE: This study aims to investigate the effect of rosuvastatin on sympathetic neural remodeling of the left atrium (LA) in rats after myocardial infarction (MI). METHODS: Rats were randomly divided into a three groups: sham group, statin group, and MI group. The mRNA expression levels of the growth-associated protein-43 (GAP43) and nerve growth factor (NGF) were measured by RT-PCR. Immunohistochemistry was used to detect the distribution and density of GAP43- and NGF-positive nerves. The expression levels of these proteins were quantified by Western blot. RESULTS: Compared with the sham group, the average optical density (AOD) values of GAP43 and nerve growth factor (NGF)-positive substances in the LA in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower than of those in the MI group (P<0.01). Furthermore, the AOD values of GAP43 and NGF positive nerves in the left stellate ganglion in the statin and MI groups were significantly higher (P<0.01), but the AOD values in the statin group were lower, when compared with the MI group (P<0.01). CONCLUSION: Rosuvastatin could effectively improve the sympathetic neural remodeling of LA in MI rats.

Rosuvastatin attenuates atrial structural remodelling in rats with myocardial infarction through the inhibition of the p38 MAPK signalling pathway.

OBJECTIVE: The purpose of this study was to verify the hypothesis that rosuvastatin attenuates atrial structural remodelling in rats with myocardial infarction (MI) through the regulation of the p38 mitogen-activated protein kinase (MAPK) signalling pathway. METHODS: A total of 66 rats were used in this study to establish a model of MI. The 56 rats that survived the first 24h after surgery were randomly divided into four groups: the control group (C group), the rosuvastatin group (R group), the low-dose torasemide group (T1 group), and the high-dose torasemide group (T2 group). The four groups of rats received daily intragastric administration of normal saline, rosuvastatin, or torasemide (T1: 1mg/kg body weight; T2: 2mg/kg body weight) for a total of four weeks. The rats in the sham-operated group (n=14) also received daily intragastric administration of normal saline for four weeks. After four weeks of intervention, the left ventricular end-diastolic pressure (LVEDP) was measured in all groups of rats by haemodynamic methods. The rats were then sacrificed, and the left atrial tissues were collected. The collagen volume fractions (CVFs) in the left atrial tissues were determined using Masson's trichrome staining. The expression of phosphorylated p38 (P-p38) MAPK in the left atrial tissues was examined by immunohistochemistry and western blot analysis. RESULTS: The results showed that LVEDP, CVF, and P-p38 MAPK expression were drastically elevated in the four MI groups in comparison to the sham-operated group (p<0.001). Rosuvastatin elevated the left ventricular fractional shortening (LVFS) and left ventricular ejection fraction (LVEF). Both rosuvastatin and torasemide improved the haemodynamic parameters. No significant difference was detected in LVEDP between the R group and the T1 group (p=0.37). In contrast, LVEDP was significantly higher in the R group than in the T2 group (p <0.05). CVF (%) was markedly decreased in the R group compared to the C, T1, and T2 groups (decreased by 47.4%, 28%, and 20.1%, respectively). Immunohistochemical analysis showed that the indices of P-p38 MAPK positive cells were significantly decreased in the R group in comparison with the C, T1, and T2 groups (decreased by 44.6%, 36.6%, and 21.4%, respectively). Western blot analysis demonstrated that P-p38 MAPK expression was markedly reduced in the R group compared with the C and T1 groups (reduced by 67% and 40.5%, respectively). The level of P-p38 MAPK in the R group was slightly higher than in the T2 group. However, the difference was not statistically significant (p>0.05). CONCLUSION: Rosuvastatin attenuates atrial structural remodelling in rats with MI. The mechanism underlying this phenomenon may be associated with the downregulation of P-p38 MAPK by rosuvastatin.

The effect of the left stellate ganglion on sympathetic neural remodeling of the left atrium in rats following myocardial infarction.

BACKGROUND: The neural remodeling of the atrium plays an important role in the initiation of atrial fibrillation after myocardial infarction (MI); however, the effects of the left stellate ganglion (LSG) on the neural remodeling of the atrium remain incompletely understood. Thus, this study investigated the mechanism by which the LSG mediates sympathetic neural remodeling of the left atrium (LA) in rats after MI. METHODS: Sixty rats were randomly divided into a Sham group and an MI group. The expression levels of growth-associated protein-43 (GAP43) and nerve growth factor (NGF) messenger ribonucleic acid (mRNA) were measured by reverse transcription polymerase chain reaction. Immunohistochemistry was used to detect the distribution and density of GAP43- and NGF-positive nerves. The expression levels of the proteins were quantified by Western blotting. RESULTS: Compared with the Sham group, GAP43 mRNA expression in the LSG was increased in the MI group (P < 0.01), but not significantly increased in the LA. Immunohistochemical analysis demonstrated that in both the LSG and the LA, the mean densities of GAP43- and NGF-positive nerves in the MI group were increased (P < 0.01). In both the LSG and the LA, the protein levels of GAP43 and NGF in the MI group were increased relative to the Sham group (P < 0.01). CONCLUSIONS: The increased levels of NGF and GAP43 proteins can induce sympathetic nerve hyperinnervation in the LSG and the LA after MI. The increased GAP43 proteins in the LA, which may have been transported from the LSG, accelerated LA sympathetic neural remodeling in rats.

Apolipoprotein A-I mimetic peptide reverse D-4F improves the biological functions of mouse bone marrow-derived late EPCs via PI3K/AKT/eNOS pathway.

Apolipoprotein A-I (ApoA-I) mimetic peptide inhibits the development of atherosclerosis (AS) in apolipoprotein E-deficient mice; however, the underlying mechanism remains unclear. Endothelial progenitor cells (EPCs) can prevent AS progression through repairing proatherogenic factors impaired endothelium. In the present study, we examined the effect of reverse D-4F, one of apoA-I mimetic peptide on the proliferation, migration, and tube formation of mouse bone marrow-derived late EPCs. The present study showed that reverse D-4F (10-100 µg/ml) significantly improved the proliferation, migration, and tube formation of EPCs in a dose-dependent manner, and activated phospho-AKT at serine residue 473 and phospho-eNOS at serine residue 1177. LY294002 (PI3-kinase inhibitor) and L-NAME (NOS inhibitor) significantly inhibited reverse D-4F mediated improvement of EPCs biological functions, and LY294002 significantly decreased reverse D-4F stimulated activation of phospho-AKT (473) and phospho-eNOS (1177). The results indicate that reverse D-4F mediated improvement of EPCs functions is dependent on the PI3K/AKT/eNOS pathway.

Pinocembrin, a major flavonoid in propolis, improves the biological functions of EPCs derived from rat bone marrow through the PI3K-eNOS-NO signaling pathway.

The number and quality of endothelial progenitor cells (EPCs) are damaged to varying degrees in patients at risk for developing atherosclerosis. The improvement of the quantity and functions of EPCs can enhance repair of injured endothelial monolayer resulting in inhibiting atherosclerosis. The purpose of this study was to investigate the effect of pinocembrin (PIN), a major flavonoid in propolis on the differentiation and biological functions of EPCs and the potential mechanisms of these effects. Flow cytometry analysis revealed that PIN treatment increased the number of CD34(+), CD133(+), FLK-1(+), CD133(+)/FLK-1(+) and CD34(+)/FLK-1(+) mononuclear cells (MNCs) in the peripheral blood of apoE(-/-) mice compared to untreated control mice. In vitro PIN treatment significantly increased the number of CD34(+), CD133(+), FLK-1(+) and CD133(+)/FLK-1(+) MNCs derived from SD bone marrow compared to untreated controls by 42.1, 84.6, 165.9 and 23.1 %, respectively. Additionally, PIN can improve biological functions of EPCs, such as proliferation, migration, adhesion, and in vitro tube formation and NO release. All of these improvements were inhibited by LY294002, while L-NAME only inhibited the PIN-induced increase in EPC proliferation and adhesion. We conclude that PIN can both promote the differentiation of EPCs in vitro and ex vivo and improve the biological functions of EPCs. The PI3K-eNOS-NO signaling pathway may be involved in the PIN-induced increase in the proliferation and adhesion of EPCs.

[Differential time attachment: optimization of the adherent time to obtain mouse bone marrow-derived endothelial progenitor cells].

The different biological functions were studied in mouse bone marrow-derived endothelial progenitor cells isolated by differential time attachment to obtain the optimal adherent time in this study. Density gradient centrifugation-isolated bone marrow mononuclear cells were seeded on the fibronectin-coated dish. The 1-day cultured unattached cells were seeded on the second dish for 2 more days. Then unattached cells in the second dish were seeded on the third dish. The cells on 3 dishes were defined as 1-day adherent cells, 3-day adherent cells and 3-day unattached cells, respectively. After 20-day culture, the biological functions, such as the percentage of biomarkers, the ability of adhesion, and the ability of forming tubes in vitro were analyzed. The results showed that the percentages of positive CD34, FLK-1, and CD34/FLK-1 expressions in 1-day attached cells were significantly increased compared to those in the 3-day adherent or unattached cells (P < 0.01), which showed the strongest adhesion ability. The expression of eNOS in 1- or 3-day adherent cells was significantly higher than that in 3-day unattached cells (P < 0.01). The expression of VEGF in 3-day adherent cells was significantly higher than that in 1-day adherent cells or 3-day unattached cells (P < 0.01). These results suggest the biological functions of 1-day adherent cells are significantly stronger than that of 3-day adherent or unattached cells. VEGF expression in 3-day adherent cells is higher than that in 1-day adherent cells or 3-day unattached cells. The expression of eNOS in 1-day adherent cells or 3-day adherent cells is higher than that in 3-day unattached cells. The optimal adherent time to obtain mouse bone marrow-derived endothelial progenitor cells is 1-3 d.

Effects of xuezhikang on proliferation and adhesion capacity of cultured endothelial progenitor cells: An in vitro study.

BACKGROUND: Endothelial progenitor cells (EPCs) might be useful in the management of coronary artery disease (CAD). OBJECTIVE: The aim of this study was to investigate the effects of xuezhikang, an extract of Chinese red yeast rice, on the proliferation and adhesion capacity of EPCs from the peripheral blood of patients with stable CAD. METHODS: Mononuclear cells from 20 Chinese patients (14 men, 6 women; mean [SD] age, 64.5 [2.8] years [range, 60-69 years]) were isolated using densitygradient centrifugation. After 4 days in culture, the attached cells were treated with different concentrations of xuezhikang (50, 125, 250, and 500 ng/mL; 20 samples/group), atorvastatin (10 ng/mL; n = 20), or phosphate-buffered saline (control, n = 20) for 3 days. Cells that were positive for 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine-labeled acetylated low-density lipoprotein and lectin were defined as EPCs. They were counted by 2 independent investigators in ≥4 randomly selected highpower fields per well. EPCs were then treated and adherent cells were counted by the independent investigators who were blinded to study drug administration. RESULTS: The mean (SD) number of cultured EPCs in the xuezhikang 50-, 125-, 250-, and 500-ng/mL groups (205 [28], 244 [31], 283 [42], and 334 [43] cells, respectively; all, P < 0.001) was significantly increased in a dose-dependent manner compared with the control group (167 [36] cells). The adhesion capacity of the EPCs was significantly greater in the 4 xuezhikang groups (51 [9], 62 [10], 71 [11], and 83 [12] cells; all, P < 0.001) when compared with that of the control group (41 [7] cells). Both the number of EPCs (327 [49] cells) and the number of adhesive EPCs (84 [15] cells) in the atorvastatin group were also significantly increased compared with the control group (both, P < 0.001); however, these increases were not significantly different from those in the xuezhikang 500-ng/mL group. CONCLUSIONS: Xuezhikang was associated with significantly enhanced proliferation and adhesion capacity of EPCs derived from the peripheral blood of these patients with stable CAD. These effects were not significantly different between xuezhikang and atorvastatin.