Silencing of osterix expression by siRNA inhibits aldosterone­induced calcification of vascular smooth muscle cells in mice.

The process of vascular calcification shares numerous similarities with that of skeletal mineralization and involves the deposition of hydroxyapatite crystals in arteries and cardiac valves. However, the underlying cellular mechanism remains to be fully elucidated. Microarray analysis in the present study demonstrated that greater than 2,000 genes were upregulated during the calcification of murine vascular smooth muscle cells (VSMCs), of which osterix (OSX) and integrin­binding sialoprotein (IBSP) were the most significantly differentially expressed genes. Following the validation of increased OSX and IBSP expression by reverse transcription­quantitative polymerase chain reaction in calcifying murine VSMCs induced by aldosterone. Subsequent to transfection with siRNA­OSX, results indicated that OSX may inhibit calcification of VSMCs via IBSP. It was suggested that the increased OSX expression in calcifying VSMCs may reflect the well­established prenatal role of OSX. A full understanding of the importance of OSX in this pathological process would improve understanding of the pathogenesis of vascular calcification.

Association of a SNP in SLC35F3 Gene with the Risk of Hypertension in a Chinese Han Population.

A recent study suggested that SLC35F3 which encoded a thiamine transporter was a new candidate gene for hypertension. The goal of this study was to investigate the association between the single-nucleotide polymorphisms (SNPs) in the SLC35F3 gene and hypertension in a Chinese population. Sanger sequencing was performed in 93 samples to find SNPs in coding regions and intron-exon boundaries in the SLC35F3 gene. We found eight genetic variants in the coding regions of SLC35F3 and subsequently genotyped a non-synonymous variant rs34032258 (C > G) in 1060 hypertension patients and 1467 controls. After adjusting for age and gender, multivariate analysis of covariance showed that the variant was associated with hypertensive traits. In detail, diastolic blood pressure (DBP) was 8 mmHg higher, blood urea nitrogen was 12 mmol/L higher, and creatinine was 15 mmol/L lower in G/G group compared with C/C group (p = 0.007; 0.012 and 0.029, respectively). Further study suggested that C/G+G/G had higher DBP than C/C genotype in those whose DBP ≥ 90 mmHg (98.02 mmHg vs. 94.04 mmHg, p = 0.021). No significant difference has been found in systolic blood pressure between different genotypes. Additionally, in the subgroup of obesity, allele distribution of this variant has shown significant difference between hypertensive patients and normotensive controls (p = 0.018). In conclusion, we found that the rs34032258 in the SLC35F3 gene was associated with high blood pressure and may increase the risk of hypertension. The new hypertension-susceptibility locus may involve in the pathogenesis of hypertension and indicate some novel treatment implications.

Complement-mediated macrophage polarization in perivascular adipose tissue contributes to vascular injury in deoxycorticosterone acetate-salt mice.

OBJECTIVE: We have previously shown an increased expression of complement 3 (C3) in the perivascular adipose tissue (PVAT) in the deoxycorticosterone acetate (DOCA)-salt hypertensive model. This study aims to examine the role and underlying mechanism of C3 in PVAT for understanding the pathogenesis of hypertensive vascular remodeling further. APPROACH AND RESULTS: The role of C3 in macrophage polarization was investigated using peritoneal macrophages from wild-type and C3-deficient (C3KO) mice because we found that C3 was primarily expressed in macrophages in PVAT of blood vessels from DOCA-salt mice, and results showed a decreased expression of M1 phenotypic marker in contrast to an increased level of M2 marker in the C3KO macrophages. Bone marrow transplantation studies further showed in vivo that DOCA-salt recipient mice had fewer M1 but more M2 macrophages in PVAT when the donor bone marrows were from C3KO compared with those from wild-type mice. Of note, this macrophage polarization shift was accompanied with an ameliorated vascular injury. Furthermore, we identified the complement 5a (C5a) as the major C3 activation product that was involved in macrophage polarization and DOCA-salt-induced vascular injury. Consistently, in vivo depletion of macrophages prevented the induction of C3 and C5a in PVAT, and ameliorated hypertensive vascular injury as well. CONCLUSIONS: The presence and activation of bone marrow-derived macrophages in PVAT are crucial for complement activation in hypertensive vascular inflammation, and C5a plays a critical role in DOCA-salt-induced vascular injury by stimulating macrophage polarization toward a proinflammatory M1 phenotype in PVAT.

Circulating endothelial progenitor cells in Chinese patients with acute stroke.

To test the hypothesis that a mobilization of endothelial progenitor cells (EPCs) occurs after acute cerebrovascular diseases, we evaluated the number of EPCs in the process of acute stroke. A total of 203 individuals were examined, including 100 patients with ischemic strokes, 36 patients with hemorrhagic strokes and 67 healthy controls. Ninety-eight patients were observed at days 1, 7, 14 and 28 after acute stroke. Circulating EPCs were defined by the surface markers CD133/KDR and analyzed by flow cytometry. Serum high sensitivity C-reactive protein (hs-CRP) concentrations were determined by particle-enhanced immunonephelometry using the N high sensitivity CRP Reagent. Patients with acute stroke had lower numbers of EPCs (0.037+/-0.001/100 peripheral blood mononuclear cells (PMNCs) vs. 0.06+/-0.002/100 PMNCs, P<0.05) and higher levels of serum hs-CRP (1.99 vs. 0.03 mg per 100 ml, P<0.05) than control subjects after adjusting for age, sex, body mass index (BMI) and blood pressure. There were no differences in EPCs counts or serum hs-CRP levels between patients with ischemic and hemorrhagic stroke. In univariate analyses, BMI, age, systolic blood pressure (SBP), diastolic blood pressure, low-density lipoprotein (LDL), total cholesterol (T-cho), blood glucose and hs-CRP (P<0.001) were inversely correlated with EPCs counts. Multivariate analyses showed SBP and total cholesterol as independent predictors of EPCs levels. The number of EPCs gradually increased at day 7 after acute onset, remained elevated at day 14; and returned to baseline by day 28. Our results suggest a possible contribution of circulating EPCs in acute stroke. SBP and total cholesterol are independent factors of reduced EPCs numbers. A transient early increment of EPCs may result from the mobilization of EPCs in response to stroke stress.

Circulating endothelial progenitor cells, C-reactive protein and severity of coronary stenosis in Chinese patients with coronary artery disease.

We sought to investigate whether numbers and activity of circulating endothelial progenitor cells (EPCs) correlate with severity of coronary stenosis as well as cardiovascular risk factors in patients with stable coronary artery disease (CAD). Number of circulating EPCs was analyzed in 104 consecutive patients with proven or clinically suspected CAD. Adhesive and migratory activity was also determined. The number of EPCs was lower in patients with a single diseased coronary artery (Group II, n=35, p<0.05 vs. Group I) or multiple diseased arteries (Group III, n=25, p<0.01 vs. Group I, p<0.05 vs. Group II) compared to those with normal coronary arteries (Group I, n=44). The number of EPCs was also related with angiographic Gensini score (r=-0.355, p=0.006). In addition, concentrations of C-reactive protein (CRP) were elevated in patients with CAD, and positively correlated with Gensini score (r=0.476, p=0.001). As for the risk factors, the number of EPCs was also inversely correlated with age (p=0.001), high sensitivity-CRP (p=0.012), hypertension (p=0.042) and family history of CAD (p=0.043). Most importantly, the migratory capacity of EPCs was compromised in patients with CAD, and inversely correlated with the angiographic Gensini score (r=-0.315, p=0.021). EPCs isolated from patients with CAD also showed an impaired adhesive activity (p<0.05). In conclusion, in patients with stable CAD, reduction in the number and impairment in the function of circulating EPCs were correlated with the severity of coronary stenosis. CRP may play an important role in reducing the number of EPCs and accelerating atherosclerosis. Given the important role of EPCs in neovascularization of ischemic tissue, a decrease in the number and activity of EPCs may contribute to the impaired vascularization in patients with CAD.

NAD(P)H oxidase-derived reactive oxygen species regulate angiotensin-II induced adventitial fibroblast phenotypic differentiation.

Phenotypic differentiation of adventitial fibroblasts into myofibroblasts is an essential feature of vascular remodeling. The present study was undertaken to test the hypothesis that reactive oxygen species (ROS) are involved in rat adventitial fibroblast differentiation to myofibroblast. Activation of alpha-smooth muscle actin (alpha-SMA) was used as a marker of myofibroblast. Angiotensin II increased intracellular ROS in adventitial fibroblasts that was completely inhibited by the free radical scavenger NAC, the NAD(P)H oxidase inhibitor DPI, and transfection of antisense gp91phox oligonucleotides. Myofibroblast differentiation was prevented by inhibition of ROS generation with DPI, NAC, and antisense gp91phox as shown by decreased expression of alpha-SMA. Angiotensin II rapidly induced phosphorylation of p38 MAPK and JNK, both of which were inhibited by DPI, NAC, antisense gp91phox, and the selective AT1 receptor antagonist, losartan. Inhibiting p38MAPK with SB202190 or JNK with SP600125 also reduced angiotensin II-induced alpha-SMA expression. These findings demonstrate that angiotensin II induces adventitial fibroblast differentiation to myofibroblast via a pathway that involves NADPH oxidase generation of ROS and activation of p38MAPK and JNK pathways.

[Number of circulating endothelial progenitor cells inversely correlate with the severity of coronary artery disease in patients with stable coronary artery disease].

OBJECTIVE: To investigate whether the number of circulating endothelial progenitor cells (EPCs) correlate with the severity of coronary stenosis in patients with stable coronary artery disease (CAD). METHODS: 80 consecutive patients who underwent coronary angiography (exclusion of acute coronary syndrome and myocardial infarction) were enrolled. Physical examination and blood tests were performed to assess the disease severity and cardiovascular risk factors. Circulating EPCs as measured by the number of CD133/KDR double positive cells were detected by FACS. RESULTS: The number of EPCs inversely correlated with age, creatinine clearance (Ccr) and left ventricular mass index (LVMI) (P = 0.004, 0.015, 0.014 respectively). Patients with hypertension showed significant reduction in number of EPCs compared to those without hypertension (P = 0.004). Moreover, the number of EPCs in patients with coronary artery disease was significantly lower than that of those with normal coronary artery (P < 0.01). EPCs also inversely correlated with angiographic Gensini score (n = 49, r = -0.305, P = 0.039). CONCLUSIONS: In patients with stable CAD, the numbers of circulating EPCs correlate with the severity of CAD as well as cardiovascular risk factors.

[Osteopontin enhances migratory ability of cultured aortic adventitial fibroblasts from spontaneously hypertensive rats].

Migration of adventitial fibroblasts (AF) is involved in the neointimal formation which is one of the common pathological processes in several vascular diseases. The observation of whether the migratory response of AF from hypertensive animal is different from that of controls may provide an explanation of vascular remodeling in hypertension. We examined whether there is any difference between the migratory activity of AF derived from spontaneously hypertensive rat (SHR) and that from their normotensive counterpart Wistar-Kyoto rats (WKY). In addition, the role of osteopontin (OPN) in cell migration was also examined. Primary cultures of aortic adventitial fibroblasts were derived from SHR and age-matched WKY. Migration of fibroblasts was determined with the Transwell method. The mRNA expression level of OPN was measured by a real-time quantitative PCR. When compared with WKY-derived cells, migration of adventitial fibroblasts from SHR exhibited an increased response when stimulated by 10% serum (cell number per field 35.20+/-5.26 vs 22.2+/-3.27, p<0.05). Chemotaxis induced by 10 ng/ml bFGF showed a similar difference (cell number per field 30.23+/-4.54 vs 19.20+/-4.47, p<0.05). We also found that SHR-derived fibroblasts expressed a higher level of OPN mRNA than the cells from WKY (1863.23+/-43.91 vs 326.24+/-68.29, p<0.01). To verify if OPN is associated with the enhanced migratory ability in AF from SHR, we designed the antisense oligonucleotide of OPN. The results showed that the antisense OPN oligonucleotide significantly inhibited AF migration (cell number per field 38.60+/-5.98 vs 26.61+/-3.84, p<0.05), while sense and mismatch OPN oligonucleotide had no effect on cell migration. Therefore, the migration of adventitial fibroblasts appeared to be enhanced in cultures derived from SHR. OPN might be involved in the difference observed.