Chi Yuan Li

Viscolin reduces VCAM-1 expression in TNF-α-treated endothelial cells via the JNK/NF-κB and ROS pathway

Viscolin, a major active component in a chloroform extract of Viscum coloratum, has antioxidative and anti-inflammatory properties. We focused on its effects on the expression of vascular cell adhesion molecule-1 (VCAM-1) in tumor necrosis factor-α (TNF-α)-treated human umbilical vein endothelial cells (HUVECs). The TNF-α-induced expression of VCAM-1 was significantly reduced by respectively 38±7 or 34±16% when HUVECs were pretreated with 10 or 30μM viscolin, as shown by Western blotting, and was also significantly reduced by pretreatment with the antioxidants N-acetylcysteine, diphenylene iodonium chloride, and apocynin. Viscolin also reduced TNF-α-induced VCAM-1 mRNA expression and promoter activity, decreased reactive oxygen species (ROS) production, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity, and significantly reduced the binding of monocytes to TNF-α-stimulated HUVECs. The attenuation of TNF-α-induced VCAM-1 expression and cell adhesion was partly mediated by a decrease in JNK phosphorylation. Furthermore, viscolin reduced VCAM-1 expression in the aorta of TNF-α-treated mice in vivo. Taken together, these data show that viscolin inhibits TNF-α-induced JNK phosphorylation, nuclear translocation of NF-κB p65, and ROS generation and thereby suppresses VCAM-1 expression, resulting in reduced adhesion of leukocytes. These results also suggest that viscolin may prevent the development of atherosclerosis and inflammatory responses.

Neutrophil-Mediated Secretion and Activation of Matrix Metalloproteinase-9 During Cardiac Surgery with Cardiopulmonary Bypass

Cardiopulmonary bypass (CPB) induces neutrophil activation, degranulation, and a systemic inflammatory response. Matrix metalloproteinase (MMP)-9 exists in neutrophils and is released on neutrophil activation. Increased levels of MMP-9 have been observed in patients undergoing CPB. We designed the present study to determine whether MMP-9 is derived from neutrophils during CPB. Twenty-one patients undergoing elective coronary artery bypass grafting with or without CPB were included in this study. Blood was collected and analyzed for MMP-9 and tissue inhibitor of metalloproteinase (TIMP)-1. Neutrophils were also isolated and examined for MMP-9 production and mRNA expression. Plasma levels and activity of MMP-9 increased significantly 2–6 h after beginning CPB, whereas the MMP-9 levels in patients with off-pump cardiac surgery did not increase. The neutrophil content of MMP-9 and mRNA increased significantly 2 h after beginning CPB. The plasma levels of TIMP-1 increased gradually for 6 h, whereas the MMP-9/TIMP-1 ratios were increased 2–4 h after beginning CPB. The present study demonstrated that CPB causes an increase in the concentration and activity of plasma MMP-9. The corresponding increase in neutrophil MMP-9 expression and production suggests that MMP-9 is derived primarily from neutrophils and may contribute to the inflammatory response associated with CPB.

Incidence of subsequent hip fractures is significantly increased within the first month after distal radius fracture in patients older than 60 years.

BACKGROUND Distal radius fracture is recognized as an osteoporosis-related fracture in aged population. If another osteoporosis-related fracture occurs in a short period, it represents a prolonged hospitalization and a considerable economic burden to the society. We evaluated the relationship between distal radius fracture and subsequent hip fracture within 1 year, especially in the critical time and age. METHODS We identified newly diagnosed distal radius fracture patients in 2000 to 2006 as an exposed cohort (N = 9,986). A comparison cohort (N = 81,227) was randomly selected from patients without distal radius fracture in the same year of exposed cohort. The subjects were followed up for 1 year since the recruited date. We compared the sociodemographic factors between two cohorts. Furthermore, the time interval following the previous distal radial fracture and the incidence of subsequent hip fracture was studied in detail. RESULTS The incidence of hip fracture within 1 year increased with age in both cohorts. The risk was 5.67 times (84.6 vs. 14.9 per 10,000 person-years) greater in the distal radial fracture cohort than in the comparison cohort. The multivariate Cox proportional hazard regression analyses showed the hazard ratios of hip fracture in relation to distal radial fracture was 3.45 (95% confidence interval = 2.59–4.61). The highest incidence was within the first month after distal radial fracture, 17-fold higher than the comparison cohort (17.9 vs. 1.05 per 10,000). Among comorbidities, age > 60 years was also a significant factor associated with hip fracture (hazard ratio = 8.67, 95% confidence interval = 4.51–16.7). CONCLUSIONS Patients with distal radius fracture and age >60 years will significantly increase the incidence of subsequent hip fracture, especially within the first month. LEVEL OF EVIDENCE Prognostic/epidemiologic study, level II.

Ganoderma lucidum polysaccharides prevent platelet-derived growth factor-stimulated smooth muscle cell proliferation in vitro and neointimal hyperplasia in the endothelial-denuded artery in vivo.

Ganoderma lucidum is used in traditional Chinese medicine to prevent or treat a variety of diseases, including cardiovascular disorders. We previously demonstrated that a glucan‐containing extract of Reishi polysaccharides (EORP) has the potent anti‐inflammatory action of reducing ICAM‐1 expression in lipopolysaccharide (LPS)‐treated human aortic smooth muscle cells (HASMCs) and LPS‐treated mice. In the present study, we examined whether EORP inhibited platelet‐derived growth factor‐BB (PDGF)‐stimulated HASMC proliferation and the mechanism involved. EORP dose‐dependently reduced cell numbers and DNA synthesis of PDGF‐treated HASMCs in vitro. EORP also arrested cell cycle progression in the G0/G1 phase, and this was associated with decreased expression of cyclin D1, cyclin E, CDK2, CDK4, and p21Cip1 and upregulation of the cyclin‐dependent kinase inhibitor p27Kip1. The anti‐proliferative effect of EORP was partly mediated by downregulation of PDGF‐induced JNK phosphorylation. In in vivo studies, the femoral artery of C57BL/6 mice was endothelial‐denuded and the mice were fed a diet containing 100 mg/kg/day of EORP. On day 14, both cell proliferation (proliferating cell nuclear antigen‐positive cells) in the neointima and the neointima/media area ratio (0.67 ± 0.03 vs. 1.46 ± 0.30) were significantly reduced. Our data show that EORP interferes with the mitogenic activation of JNK, preventing entry of HASMCs into the cell cycle in vitro and reducing cell proliferation in the neointima and decreasing the neointimal area in vivo. Thus, EORP may represent a safe and effective novel approach to the prevention and treatment of vascular proliferative diseases. J. Cell. Physiol. 227: 3063–3071, 2012.

Poincaré plot indexes of heart rate variability detect dynamic autonomic modulation during general anesthesia induction

PURPOSE Beat-to-beat heart rate variability (HRV) is caused by the fluctuating balance of sympathetic and parasympathetic tone. The Poincaré plot has been used to evaluate HRV. In this study, we validate that this new method may qualitatively and quantitatively assess the sympathovagal fluctuation in patients during induction of anesthesia with sevoflurane. METHODS Twenty-eight young patients were allocated for the study. The patients received a tilt test and on the next day they sustained anesthesia induced with inhaled anesthetics. Electrocardiography signals from the patients were relayed to an analogue-digital converter. The Poincaré plot is quantified by measuring SD1, SD2, and SD1/SD2. Power spectral analyses were performed and LF, HF and HF/LF were calculated. RESULTS The LF power and the SD2 of the Poincaré plot increased while subjects were tilt-up from the supine position. Additionally, a significant correlation were found between LF and SD2, HF and SD1 (p < 0.05), and LF/HF and SD2/SD1 (p < 0.01). Sevoflurane inhalation for 10 minutes had no effect on heart rate, but diminished LF, total power and SD1, SD2 of the Poincaré plot respectively. However, the LF, SD2 and LF/HF increased; the HF, SD1 and SD1/SD2 ratio decreased after intubation stimulation. CONCLUSION Poincaré plot and power spectral analysis of HRV during tilt test and sevoflurane induction significantly correlate. Poincaré plot analysis is easier and more sensitive at evaluating the sympathovagal balance and observing the beat-to-beat HRV.

Gallic Acid Attenuates Platelet Activation and Platelet-Leukocyte Aggregation: Involving Pathways of Akt and GSK3β

Platelet activation and its interaction with leukocytes play an important role in atherothrombosis. Cardiovascular diseases resulted from atherothrombosis remain the major causes of death worldwide. Gallic acid, a major constituent of red wine and tea, has been believed to have properties of cardiovascular protection, which is likely to be related to its antioxidant effects. Nonetheless, there were few and inconsistent data regarding the effects of gallic acid on platelet function. Therefore, we designed this in vitro study to determine whether gallic acid could inhibit platelet activation and the possible mechanisms. From our results, gallic acid could concentration-dependently inhibit platelet aggregation, P-selectin expression, and platelet-leukocyte aggregation. Gallic acid prevented the elevation of intracellular calcium and attenuated phosphorylation of PKCα/p38 MAPK and Akt/GSK3β on platelets stimulated by the stimulants ADP or U46619. This is the first mechanistic explanation for the inhibitory effects on platelets from gallic acid.

TNF-α inhibits toll-like receptor 4 expression on monocytic cells via tristetraprolin during cardiopulmonary bypass

Toll-like receptor 4 (TLR4) plays a major role in regulating the innate immune response, which is related to postoperative complications. Although inflammatory capacity and TNF-&agr; synthesis were altered on monocytes after cardiopulmonary bypass (CPB), whether the CPB and the CPB-induced TNF-&agr; affect TLR4 expression on monocytes have not yet clarified. We speculate that the changing of TNF-&agr; level during CPB may be involved in monocytic TLR4 expression. As previous report, our enzyme-linked immunosorbent assay showed that CPB elevated the plasma level of TNF-&agr;, whereas off-pump cardiac surgery does not. Flow cytometry reported decreased levels of monocytic TLR4 in patients undergoing CPB but not undergoing off-pump cardiac surgery. To elucidate whether the CPB-induced TNF-&agr; is related to TLR4 down-regulation, we used human monocytic THP-1 cells. Actinomycin D chase experiments demonstrated that TNF-&; decreased TLR4 expression and TLR4 mRNA stability on THP-1. Confocal microscopy and real-time polymerase chain reaction showed that TNF-&agr; induced intracellular tristetraprolin (TTP) expression. Transfection with TTP siRNA reversed the down-regulation of TLR4 in TNF-&agr;-stimulated THP-1. Treatment with ERK1/2 inhibitor and SAPK/JNK inhibitor decreased TNF-&agr;-induced TTP expression. Immunoprecipitation and Western blot analysis showed that the TNF-&agr;-mediated activation of TTP might be inhibited by p38 mitogen-activated protein kinase inhibitor and by PD98059. We also demonstrated in clinical samples with confocal microscopy and flow cytometry that CPB led to an elevation of TTP in monocytes. In conclusion, CPB and TNF-&agr; decrease TLR4 expression on monocytes; TTP expression and mitogen-activated protein kinase-signaling pathways play critical roles in CPB- and TNF-&agr;-mediated decreases of TLR4 on monocytes. Our results suggest that using TTP to control cytokine message decay rate may be a promising approach for controlling system inflammation and preventing post-CPB complications.

Sevoflurane anesthesia attenuates adenosine diphosphate-induced P-selectin expression and platelet-leukocyte conjugate formation.

The expression of P-selectin on the surface of platelets and platelet-leukocyte conjugate formation are considered to be an indicator of platelet activation and are important in thrombotic and inflammatory disease. Previous studies have reported the inhibitory effects of sevoflurane on platelet aggregation. We investigated whether sevoflurane alters the expression of P-selectin on platelets and the formation of platelet-leukocyte conjugates. Twenty-five patients undergoing minor extremity surgery received sevoflurane-based general anesthesia, with mask induction and laryngeal mask airway anesthesia maintenance. Whole blood was obtained before and 40 min after sevoflurane anesthesia. Unstimulated and adenosine diphosphate-stimulated samples of whole blood and platelet rich plasma were stained with fluorochrome-conjugated antibodies. The expression of P-selectin on platelets and the formation of platelet-leukocyte conjugates were measured using flow cytometry. Sevoflurane inhibited platelet P-selectin expression. It also reduced the formation of platelet-leukocyte conjugates, both in unstimulated and adenosine diphosphate-stimulated blood samples at 3%–4% end-expiratory sevoflurane concentrations used to maintain anesthesia.

Magnolol Reduced TNF-α-Induced Vascular Cell Adhesion Molecule-1 Expression in Endothelial Cells via JNK/p38 and NF-κB Signaling Pathways

Expression of cell adhesion molecules by the endothelium and the attachment of leukocytes to these cells play major roles in inflammation and cardiovascular disorders. Magnolol, a major active component of Magnolia officinalis, has antioxidative and anti-inflammatory properties. In the present study, the effects of magnolol on the expression of vascular cell adhesion molecule-1 (VCAM-1) in human aortic endothelial cells (HAECs) and the related mechanisms were investigated. TNF-α induced VCAM-1 protein expression and mRNA stability were significantly decreased in HAECs pre-treated with magnolol. Magnolol significantly reduced the phosphorylation of ERK, JNK, and p38 in TNF-α-treated HAECs. The decrease in VCAM-1 expression in response to TNF-α treatment was affected by JNK and p38 inhibitors, not by an ERK inhibitor. Magnolol also attenuates NF-κB activation and the translocation of HuR (an RNA binding protein) in TNF-α-stimulated HAECs. The VCAM-1 expression was weaker in the aortas of TNF-α-treated apo-E deficient mice with magnolol treatment. These data demonstrate that magnolol inhibits TNF-α-induced JNK/p38 phosphorylation, HuR translocation, NF-κB activation, and thereby suppresses VCAM-1 expression resulting in reduced leukocyte adhesion. Taken together, these results suggest that magnolol has an anti-inflammatory property and may play an important role in the prevention of atherosclerosis and inflammatory responses.

Lidocaine priming reduces ADP-induced P-selectin expression and platelet-leukocyte aggregation

BACKGROUND Activation of platelets, which plays an important role in inflammation, has recently been reported to enhance platelet P-selectin expression and form platelet-leukocyte aggregation (PLA). Platelet P-selectin expression and PLA formation have been reported to be potential markers of inflammatory diseases such as sepsis, thrombosis, myocardial ischemic disorders and stroke. Lidocaine, one of the most commonly used anesthetics, is known to inhibit platelet function, but its effect on platelet P-selectin expression and PLA remains unclear. METHODS To determine the effect of lidocaine on platelet activation, and on platelet activation-related septic condition (lipopolysaccharide-induced), we treated platelets with lidocaine (0.03-3 mM) and then measured platelet P-selectin expression and PLA. Whole blood for in vitro study was obtained from healthy men aged 27 to 33 years who had not taken any medication for at least 15 days. RESULTS All samples were analyzed by flow cytometry. We found that lidocaine produced a concentration-dependent inhibition of P-selectin expression and PLA. Moreover, in lipopolysaccharide-challenged samples, lidocaine at concentrations of 1-3 mM inhibited PLA. CONCLUSION Our findings may help to elucidate the inhibitory role of lidocaine on platelet P-selectin expression and PLA and infer possible therapeutic targets in the treatment of inflammatory diseases. However, further investigations are needed to determine whether the observed attenuation of excessive inflammatory responses has clinical implications. These results suggest that lidocaine might have potential clinical application in the modulation of excessive platelet activation, inflammatory response and septic condition.