A nomogram based on endothelial function and conventional risk factors predicts coronary artery disease in hypertensives.

BACKGROUND: There is currently a lack of a precise, concise, and practical clinical prediction model for predicting coronary artery disease (CAD) in patients with essential hypertension (EH). This study aimed to construct a nomogram to predict CAD in patients with EH based on flow-mediated dilation (FMD) of brachial artery and traditional risk factors. METHODS: Clinical data of 1752 patients with EH were retrospectively collected. High-resolution vascular ultrasound was used to detect FMD in all patients at the Fujian Hypertension Research Institute, China. Patients were divided into two groups, i.e. training group (n = 1204, from August 2000 to December 2013) and validation group (n = 548, from January 2014 to May 2016) according to the time of enrollment. Independent predictors of CAD were analyzed by multivariable logistic regression in the training group, and a nomogram was constructed accordingly. Finally, we evaluated the discrimination, calibration, and clinical applicability of the model using the area under curve (AUC) of receiver operating characteristic analysis, calibration curve combined with Hosmer-Lemeshow test, and decision curve, respectively. RESULTS: There were 263 (21.8%) cases of EH combined with CAD in the training group. Multivariate logistic regression showed that FMD, age, duration of EH, waist circumference, and diabetes mellitus were independent influencing factors for CAD in EH patients. Smoking which was close to statistical significance (P = 0.062) was also included in the regression model to increase the accuracy. Ultimately, the nomogram for predicting CAD in EH patients was constructed according to above predictors after proper transformation. The AUC values of the training group and the validation group were 0.799 (95%CI 0.770-0.829) and 0.836 (95%CI 0.787-0.886), respectively. Calibration curve and Hosmer-Lemeshow test showed that the model had good calibration (training group: χ2 = 0.55, P = 0.759; validation group: χ2 = 1.62, P = 0.446). The decision curve also verified the clinical applicability of the nomogram. CONCLUSION: The nomogram based on FMD and traditional risk factors (age, duration of EH disease, smoking, waist circumference and diabetes mellitus) can predict CAD high-risk group among patients with EH.

Development of a Rat Model of Sick Sinus Syndrome Using Pinpoint Press Permeation.

OBJECTIVE: Sick sinus syndrome (SSS) is one of the most common causes of cardiac impairment necessitating pacemaker implantation. However, studies of SSS pathogenesis are neither comprehensive nor conclusive due to limited success in achieving a stable rat SSS model. Here, we modified pinpoint press permeation to establish a stable rat SSS model. METHODS: We randomly assigned 138 male Sprague-Dawley rats into three groups: normal control (n = 8), sham (n = 10), and SSS (n = 120). Postoperatively, the SSS group was further divided into SSSA (n = 40), SSSB (n = 40), and SSSC (n = 40), based on reduction in heart rates by 20-30%, 31-40%, and 41-50%, respectively. We also assessed histomorphological characteristics and hyperpolarization-activated cyclic nucleotide-gated cation channel 4 (HCN4) expression in the sinoatrial node (SAN) at 1, 2, 3, and 4 weeks after surgery. RESULTS: Mortality was statistically higher in SSSC compared to SSSA and SSSB (7.5% versus 90.0% and 87.5%; P < 0.05). Heart rate in SSSA was gradually restored to preoperative levels by week 4 after surgery. In contrast, heart rate in SSSB was stable at 2-3 weeks after surgery. However, we observed that the tissues and cells in SAN were severely injured and also found a time-dependent increase in collagen content and atrium myocardium in SSSB. HCN4 expression was significantly reduced at all 4 time points in SSSB, with statistically significant differences among the groups (P < 0.01). CONCLUSION: We successfully developed a rat SSS model that was sustainable for up to 4 weeks.

Human tissue kallikrein 1 gene delivery inhibits PDGF-BB-induced vascular smooth muscle cells proliferation and upregulates the expressions of p27Kip1 and p2lCip1.

Tissue kallikrein 1 cleaves kininogen substrate to produce vasoactive kinin peptides that have been implicated in inhibiting neointimal hyperplasia in rat carotid arteries after balloon injury. However, its effects on the proliferation, cell cycle and its mechanisms, for example, cyclin-dependent kinase inhibitors, p27(Kip1) and p2l(Cip1) in vascular biology are poorly understood. The objective of this study was to explore the effects of human tissue kallikrein 1 (hTK1) mediated by recombinant adenovirus (Ad-hTK1) on proliferation and cell cycle of vascular smooth muscle cells (VSMCs) derived from spontaneously hypertensive rats induced by platelet-derived growth factor-BB (PDGF-BB) in vitro. The results showed that, within a given multiplicity of infection (MOI) and time, the hTK1 gene delivery inhibited PDGF-BB-stimulating VSMCs growth in a concentration-dependent (20-100 MOI) and time-dependent (2-5 days) manner by cell counting, with a peak inhibition rate at 36.3% at 72 h (P < 0.01). In addition, hTK1 gene delivery significantly suppressed PDGF-BB-induced proliferation of VSMCs by methyl thiazolyl tetrazoliuin assay, and decreased the percentage of cells in the S phase and in DNA synthesis by flow cytometry, with a peak inhibition rate at 30.2 and 36.4%, respectively (P < 0.01). Western blot assay showed that the protein levels of p27(Kip1) and p2l(Cip1) in cells infected with Ad-hTK1 were much more abundant than those in cells only induced by PDGF-BB, with up-modulating rates at 51.8 and 58.7%, respectively (P < 0.001). We also observed that the effects of hTK1 gene delivery in inhibiting VSMCs proliferation, arresting cell cycling in G(0)/G(1) phase and up-regulating the expression of p27(Kip1) and p2l(Cip1) could be blocked by icatibant (Hoe 140), a specific bradykinin B(2) receptor antagonist. Taken together, these results demonstrated that hTK1 overexpressed by recombinant adenovirus potently inhibits VSMCs proliferation that is required for neointimal hyperplasia and restenosis, and may activate p27(Kip1) and p2l(Cip1) signaling pathways via bradykinin B(2) receptor.

[Effect of atorvastatin on advanced glycation end products induced monocyte chemoattractant protein-1 expression in cultured human endothelial cells].

OBJECTIVE: To investigate the effects of atorvastatin on advanced glycation end products (AGE) induced monocyte chemoattractant protein-1 (MCP-1) expression in human umbilical vein endothelial cells (HUVECs) and whether this effect could be linked to peroxisome proliferator-activated receptor-γ (PPAR-γ) and nuclear factor-κB (NF-κB). METHODS: Grouping: (1) Blank control group; (2) BSA group; (3) AGE group: cells were incubated with different concentrations of AGE (10(-4), 10(-3), 10(-2) and 10(-1) g/L) for 24 hours; (4) AGE + Atorvastatin group: cells were incubated with different concentrations of atorvastatin (0.1, 1, 10 µmol/L) for 1 hour, then incubated with AGE (10(-1) g/L) for 24 hours; (5) PPAR-γ agonist (15 d-PGJ2) group: cells were incubated with 15 d-PGJ2 (10 µmol/L) for 1 hour, then incubated with AGE (10(-1) g/L) for 24 hours; (6) PPAR-γ inhibitor (GW9662) group: cells were incubated with GW9662 (5000 nmol/L) for 1 hour, then incubated with atorvastatin (1 µmol/L) and AGE (10(-1) g/L) for 24 hours. Collagenase was used to isolate the endothelial cell from human umbilical vein; RT-PCR was performed to examine the mRNA expression of MCP-1 and PPAR-γ; Western blot was performed to detect NF-κB p65 protein. RESULTS: (1) The expression of MCP-1 mRNA was increased in proportion with increasing concentrations of AGEs which could be blocked by atorvastatin in a dose-dependent manner. (2) AGE (10(-1) g/L) significantly downregulated the expression of PPAR-γ mRNA (0.22 ± 0.08 vs. 0.69 ± 0.09, P < 0.01) while upregulated the expression of phospho-NF-κB p65 protein (0.78 ± 0.06 vs. 0.31 ± 0.01, P < 0.01) and nonphospho-NF-κB p65 protein (1.61 ± 0.16 vs. 0.59 ± 0.14, P < 0.01) compared with the control group which could be significantly attenuated by atorvastatin. (3) PPAR-γ agonist decreased the expression of phospho-NF-κB p65 protein (0.21 ± 0.01 vs. 0.78 ± 0.06, P < 0.01), nonphospho-NF-κB p65 protein (0.67 ± 0.14 vs. 1.61 ± 0.16, P < 0.01) and MCP-1 mRNA (0.17 ± 0.02 vs. 0.93 ± 0.12, P < 0.01) compared with AGE (10(-1) g/L) group. (4) PPAR-γ inhibitor antagonized the effect of atorvastatin on the expression of phospho-NF-κB p65 protein, nonphospho-NF-κB p65 protein and MCP-1 mRNA stimulated by AGE in HUVECs (P < 0.01). CONCLUSION: The anti-inflammatory properties of atorvastatin in AGE stimulated HUVECs may partly be attributed to the effect on upregulation of PPAR-γ and downregulation of NF-κB signaling pathway.

[Effects of human tissue kallikrein gene delivery on the proliferation of vascular smooth muscle cells].

OBJECTIVE: Tissue kallikrein cleaves kininogen substrate to produce vasoactive kinin peptides that have been implicated in the proliferation of vascular smooth muscle cells. We investigated the effects of adenovirus-mediated human tissue kallikrein (Ad-hKLK1) gene delivery on the proliferation of vascular smooth muscle cells of SHR (VSMCs(SHR)) induced by platelet derived growth factor-BB (PDGF-BB). METHODS: Primary VSMCs(SHR) were isolated and cultured from thoracic aorta of male SHR. The VSMCs(SHR) proliferation induced by PDGF-BB was accessed by cell counting and methyl thiazolyl tetrazolium (MTT). Western blot was used to determine the protein expression of hKLK1, the cycle-independent kinase inhibitors p27(Kip1) and p21(Cip1). The mRNA expressions of bradykinin B1 receptor and B2 receptor were detected by RT-PCR in VSMCs(SHR). RESULTS: Proliferation of VSMCs(SHR) induced by PDGF-BB was significantly inhibited post transfection of Ad-hKLK1 (20-100 MOI) in a MOI-dependent manner. The peak inhibition titer of Ad-hKLK1 was 100 MOI with peak inhibition rate of 39.3% (cell counting, n = 3, P < 0.01), 30.2% (MTT, n = 3, P < 0.01) and 36.4% (peak stunning rate of cell-cycle in phase G(0)/G(1)). The inhibitory effects of proliferation and cell-cycle caused by hKLK1 gene delivery could be abolished by Hoe140, a bradykinin B2 receptor antagonist. The protein expression of p27(Kip1) and p21(Cip1) increased significantly after the hKLK1 gene delivery, whereas Hoe140 nearly completely blocked these effects (n = 3, P < 0.001, respectively). PDGF-BB also significantly upregulated the mRNA expression of B2 receptor but not B1 receptor in VSMCs(SHR). CONCLUSION: The hKLK1 gene delivery could inhibit PDGF-BB induced proliferation in VSMCs(SHR) through Bradykinin B2 receptor and up-regulate expression of p27(Kip1) and p2l(Cip1).

[Effects of human tissue kallikrein gene transfer on the migration of vascular smooth muscule cells].

OBJECTIVE: To investigate the effects of adenovirus-mediated human tissue kallikrein (Ad-hKLK1) gene transfer on platelet-derived growth factor-BB (PDGF-BB)-induced migration of vascular smooth muscle cells from spontaneously hypertensive rats (VSMC(SHR)). METHODS: A bicistronic recombinant adenovirus vector (Ad-hKLK1) carrying the target hKLK1 gene and the reporter gene EGFP was constructed. VSMCs isolated from the thoracic aorta of male SHR were passaged, and the quiescent VSMC(SHR) in passages 3-6 seeded in 6-well plates were treated with Ad-hKLK1 and control virus. Human PDGF-BB or icatibant Hoe140, a BK B2 antagonistat, was used as the chemoattractant and placed in the bottom chamber of the Boyden chamber. The mRNA expressions of bradykinin B1 receptor and B2 receptor were detected by RT-PCR in VSMC(SHR). RESULTS: hKLK1 gene transfer significantly inhibited PDGF-BB-induced migration of VSMC(SHR), with the peak inhibition rate of 34.6% (P<0.001). PDGF-BB significantly increased the mRNA expression of B2 receptor but not B1 receptor in VSMC(SHR). CONCLUSIONS: hKLK1 gene transfer can inhibit the migration of VSMC(SHR) induced by PDGF-BB, and the inhibitory effects may be not mediated by bradykinin B2 receptor.

The signal transduction pathways of heat shock protein 27 phosphorylation in vascular smooth muscle cells.

The objective of this study is to investigate the signal transduction pathways that regulate heat shock protein 27 (HSP27) phosphorylation and migration of vascular smooth muscle cells (VSMCs) from spontaneously hypertensive rats (SHR) induced by angiotensin II (AngII) and platelet derived growth factor-BB (PDGF-BB). The activity of HSP27 was evaluated by Western blot with specific phospho-HSP27 antibody. F-actin polymerization was detected by FITC-Phalloidine staining using confocal microscopy. Modified Boyden chamber technique was employed for VSMCs migration assessment. Within a given concentration, the phosphorylation of HSP27 induced by AngII and PDGF-BB was blocked by the specific P38MAPK inhibitor SB202190, the specific PI3K inhibitor LY294002 and the specific ERK1/2 inhibitor U0126 in a concentration-dependent manner, with a peak inhibition rate at 87.2%, 78.4% and 37.3%, respectively, induced by AngII (P < 0.01), with a peak inhibition rate at 85.0%, 55.3% and 41.0%, respectively, induced by PDGF-BB (P < 0.01).The migration of VSMCs induced by AngII and PDGF-BB was inhibited by 100 micromol/l SB202190, 30 micromol/l LY294002, and 30 micromol/l U0126, with a inhibition rate at 60.1%, 71.7% and 47.3%, respectively, provoked by AngII (P < 0.01), with a inhibition rate at 55.3%, 55.6% and 38.1%, respectively, provoked by PDGF-BB (P < 0.01). P38MAPK and PI3 K/Akt are important pathways that contribute to the phosphorylation of HSP27 and migration of VSMCs in response to AngII and PDGF-BB. ERK1/2 might be involved in HSP27 phosphorylation and migration of VSMCs provoked by AngII and PDGF-BB.

Role of heat shock protein 27 phosphorylation in migration of vascular smooth muscle cells.

OBJECTIVE: The aim of the present study was to investigate the role of heat shock protein 27 (HSP27) phosphorylation in the migration of vascular smooth muscle cells (VSMCs) induced by angiotensin II (AngII) and platelet derived growth factor-BB (PDGF-BB). METHODS: The activity of HSP27 was evaluated by Western blot with specific phospho-HSP27 antibody. F-actin polymerization was detected by FITC-Phalloidine staining using confocal microscopy. Modified Boyden chamber technique was employed for VSMCs migration assessment. RESULTS: The phosphorylation of HSP27 was induced by AngII and PDGF-BB in a time- and concentration-dependent manner in VSMCs, which was significantly blocked by the HSP inhibitor Quercetin in a concentration-dependent manner. Reorganization of actin stimulated by AngII and PDGF-BB was markedly inhibited by pretreatment with 100 micromol/l Quercetin. The migration of VSMCs induced by AngII and PDGF-BB was partially inhibited by Quercetin with peak inhibition concentration at 100 micromol/l. CONCLUSIONS: HSP27 phosphorylation plays an important role in mediating the rearrangement of F-actin and migration of VSMCs induced by AngII and PDGF-BB. HSP27 may be a potential target for the interventional treatment of pathological process related to cell migration.