Impairment of endothelium-dependent aorta relaxation by phospholipid components of oxidized low-density lipoprotein

Effects of Danhong Injection (丹红注射液) and its main components on anticoagulation and fibrinolysis in cultured vein endothelial cells

OBJECTIVE

To observe the effects of Danhong Injection (丹红注射液) and its main components, including daiclzein and hydroxysafflor yellow A (HSYA), on the anticoagulation, fibrinolysis, anti-apoptosis in hypoxia model of vein endothelial cells (VECs).

METHODS

VECs were prepared and were put in a hypoxia environment, which consisted of mixed gas of 95% N and 5% CO mixed gas, when reached confluent culture. Five groups used different treatments, including normal control group, hypoxia group, daiclzein group, HSYA group and Danhong Injection group. The VECs were identified by fluorescence double labeling methods. The morphology was observed by a phase contrast microscopy. The effects of Danhong Injection, daiclzein and HSYA on 6 keto prostaglandin F1α (6-keto-PGF1α) level was measured by the method of radioimmunoassay (RIA). Superoxide dismutase (SOD) activity was tested by water soluble tetrazolium salt. The content of malondialdehyde (MDA) was measured by thiobarbituric acid. The activities of tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) were measured by the method of chromogenic substrate. The contents of endothelin (ET) and nitric oxide (NO) were detected by non-equilibrium RIA and enzymelinked immunosorbent assay. Cells apoptosis rate was determined by flow cytometry.

RESULTS

Compared with the normal control group, the floating cells number, PAI activity, ET and MDA contents, and cells apoptosis rate in the culture solution of hypoxia group were all significantly increased, whereas the 6-keto-PGF1α and NO contents, and t-PA and SOD activities were decreased significantly (P<0.01). Compared with the hypoxia group, Danhong Injection markedly increased the 6-keto-PGF1α content and SOD activity, regulated PAI and t-PA activities, ET and NO contents, and decreased MDA content and cells apoptosis rate (P<0.05 or P<0.01).

CONCLUSIONS

Danhong Injection and its main components played an important role in protecting primary VECs from hypoxic damage by regulating the secretion and vasomotor function of VECs. The function of Danhong Injection was most remarkable.

OxLDL induces endothelial dysfunction and death via TRAF3IP2: inhibition by HDL3 and AMPK activators

Oxidized low-density lipoprotein (oxLDL) induces endothelial cell death through the activation of NF-κB and AP-1 pathways. TRAF3IP2 is a redox-sensitive cytoplasmic adapter protein and an upstream regulator of IKK/NF-κB and JNK/AP-1. Here we show that oxLDL-induced death in human primary coronary artery endothelial cells (ECs) was markedly attenuated by the knockdown of TRAF3IP2 or the lectin-like oxLDL receptor 1 (LOX-1). Further, oxLDL induced Nox2/superoxide-dependent TRAF3IP2 expression, IKK/p65 and JNK/c-Jun activation, and LOX-1 upregulation, suggesting a reinforcing mechanism. Similarly, the lysolipids present in oxLDL (16:0-LPC and 18:0-LPC) and minimally modified LDL also upregulated TRAF3IP2 expression. Notably, whereas native HDL3 reversed oxLDL-induced TRAF3IP2 expression and cell death, 15-lipoxygenase-modified HDL3 potentiated its proapoptotic effects. The activators of the AMPK/Akt pathway, adiponectin, AICAR, and metformin, attenuated superoxide generation, TRAF3IP2 expression, and oxLDL/TRAF3IP2-mediated EC death. Further, both HDL3 and adiponectin reversed oxLDL/TRAF3IP2-dependent monocyte adhesion to endothelial cells in vitro. Importantly, TRAF3IP2 gene deletion and the AMPK activators reversed oxLDL-induced impaired vasorelaxation ex vivo. These results indicate that oxLDL-induced endothelial cell death and dysfunction are mediated via TRAF3IP2 and that native HDL3 and the AMPK activators inhibit this response. Targeting TRAF3IP2 could potentially inhibit progression of atherosclerotic vascular diseases.

Systems genetics analysis of gene-by-environment interactions in human cells

Gene by environment (GxE) interactions are clearly important in many human diseases, but they have proven to be difficult to study on a molecular level. We report genetic analysis of thousands of transcript abundance traits in human primary endothelial cell (EC) lines in response to proinflammatory oxidized phospholipids implicated in cardiovascular disease. Of the 59 most regulated transcripts, approximately one-third showed evidence of GxE interactions. The interactions resulted primarily from effects of distal-, trans-acting loci, but a striking example of a local-GxE interaction was also observed for FGD6. Some of the distal interactions were validated by siRNA knockdown experiments, including a locus involved in the regulation of multiple transcripts involved in the ER stress pathway. Our findings add to the understanding of the overall architecture of complex human traits and are consistent with the possibility that GxE interactions are responsible, in part, for the failure of association studies to more fully explain common disease variation.

Vasorelaxant and anti-platelet aggregation effects of aqueous Ocimum basilicum extract

AIM OF THE STUDY

In this work the endothelium-dependant vasorelaxant and anti-platelet aggregation activities of an aqueous extract from Ocimum basilicum were studied.

MATERIALS AND METHODS

The vasorelaxant effect was undertaken in thoracic aorta from three experimental groups of rats: one of them (NCG) fed with standard diet, the second (HCG) with hypercholesterolemic diet (HCD) and the third (BTG) with hypercholesterolemic diet together with an intragastric administration of Ocimum basilicum extract at a dose of 0.5 g/kg body weight for a period of 10 weeks. The in vitro anti-platelet aggregation of Ocimum basilicum extract was studied using thrombin (0.5 U/ml) and ADP (5 microM) as agonists.

RESULTS

The results show that the HCD statistically decreases vascular relaxation in HCG compared to NCG (p<0.001) and increases the vascular responses to phenylephrine (p<0.02). Ocimum basilicum extract exerts a significant vasorelaxant effect at 10(-5) M (p<0.01) and 10(-4) M carbachol (p=0.001). The plant extract also tends to suppress the elevated contractions induced by HCD (p=0.05). The extract inhibits ADP-induced platelet aggregation by 13%, 28.2%, 30.5%, 44.7% and 53% at a dose of 1, 2, 3, 4 and 5 g/l, respectively. Thrombin-induced platelet activation was also reduced by 15%, 23%, 40%, 38.4%, and 42% at the same doses of extract described above.

CONCLUSION

The use of Ocimum basilicum as medicinal plant could be beneficial for cardiovascular system.