S. Muid

Delta- and gamma-tocotrienol isomers are potent in inhibiting inflammation and endothelial activation in stimulated human endothelial cells

Background Tocotrienols (TCTs) are more potent antioxidants than α-tocopherol (TOC). However, the effectiveness and mechanism of the action of TCT isomers as anti-atherosclerotic agents in stimulated human endothelial cells under inflammatory conditions are not well established. Aims 1) To compare the effects of different TCT isomers on inflammation, endothelial activation, and endothelial nitric oxide synthase (eNOS). 2) To identify the two most potent TCT isomers in stimulated human endothelial cells. 3) To investigate the effects of TCT isomers on NFκB activation, and protein and gene expression levels in stimulated human endothelial cells. Methods Human umbilical vein endothelial cells were incubated with various concentrations of TCT isomers or α-TOC (0.3–10 µM), together with lipopolysaccharides for 16 h. Supernatant cells were collected and measured for protein and gene expression of cytokines (interleukin-6, or IL-6; tumor necrosis factor-alpha, or TNF-α), adhesion molecules (intercellular cell adhesion molecule-1, or ICAM-1; vascular cell adhesion molecule-1, or VCAM-1; and e-selectin), eNOS, and NFκB. Results δ-TCT is the most potent TCT isomer in the inhibition of IL-6, ICAM-1, VCAM-1, and NFκB, and it is the second potent in inhibiting e-selectin and eNOS. γ-TCT isomer is the most potent isomer in inhibiting e-selectin and eNOS, and it is the second most potent in inhibiting is IL-6, VCAM-1, and NFκB. For ICAM-1 protein expression, the most potent is δ-TCT followed by α-TCT. α- and β-TCT inhibit IL-6 at the highest concentration (10 µM) but enhance IL-6 at lower concentrations. γ-TCT markedly increases eNOS expression by 8–11-fold at higher concentrations (5–10 µM) but exhibits neutral effects at lower concentrations. Conclusion δ- and γ-TCT are the two most potent TCT isomers in terms of the inhibition of inflammation and endothelial activation whilst enhancing eNOS, possibly mediated via the NFκB pathway. Hence, there is a great potential for TCT isomers as anti-atherosclerotic agents.

Bisphenol A exposure disturbs the bone metabolism: An evolving interest towards an old culprit

Abstract Bisphenol A (BPA) (2,2,‐bis (hydroxyphenyl) propane), a well‐known endocrine disruptor (ED), is the exogenous chemical that mimic the natural endogenous hormone like oestrogen. Due to its extensive exposure to humans, BPA is considered to be a major toxicological agent for general population. Environmental exposure of BPA results in adverse health outcomes including bone loss. BPA disturbs the bone health by decreasing the plasma calcium level and inhibiting the calcitonin secretion. BPA also stimulated differentiation and induced apoptosis in human osteoblasts and osteoclasts. However, little is known about the underlying mechanisms of the untoward effect of BPA against bone metabolism. The present review gives an overview on the possible mechanisms of BPA towards bone loss. The previous literature shows that BPA exerts its toxic effect on bone cells by binding to the oestrogen related receptor‐gamma (ER&ggr;), reducing the bone morphogenic protein‐2 (BMP‐2) and alkaline phosphatase (ALP) activities. BPA interrupts the bone metabolism via RANKL, apoptosis and Wnt/&bgr;‐catenin signaling pathways. It is, however, still debated on the exact underlying mechanism of BPA against bone health. We summarised the molecular evidences with possible mechanisms of BPA, an old environmental culprit, in bone loss and enlightened the underlying understanding of adverse action of BPA in the society. Graphical abstract Figure. Unlabelled Image

Atheroprotective effects of pure tocotrienol supplementation in the treatment of rabbits with experimentally induced early and established atherosclerosis

Background Atherosclerosis is the main cause of coronary artery disease -related deaths worldwide. The atheroprotective properties of pure tocotrienols (T3) in the absence of alpha-tocopherol (α-TCP) in vitamin E has not been extensively examined. Aim To determine the atheroprotective properties of T3 in early and established atherosclerosis rabbits. Methods Thirty New Zealand white rabbits were divided into two groups, B1 and B2 which represent early [fed 1% high cholesterol diet (HCD) for 2 weeks] and established (fed 1% HCD for 8 weeks) atherosclerosis. Each group was subdivided into three intervention arms: 1) T3–4 mg/kg, 2) T3–15 mg/kg and 3) vehicle without T3 (T3 negative) for 8 weeks. Serial fasting blood samples were obtained for lipid profile, and whole lengths of aorta were used to determine tissue markers of endothelial activation, inflammation and plaque stability. Results In B1, atherosclerotic lesion in T3–4 mg/kg group was significantly reduced (p=0.008), while aortic tissue expression of vascular cellular adhesion molecule 1 (VCAM-1), interleukin-6 (IL-6) and matrix metalloproteinase (MMP-12) was reduced in T3–4 mg/kg compared to T3-negative rabbits group (0.2±0.1 vs. 28.5±3.1%; 3.0±1.6 vs. 14.0±1.7%; and 5.2±2.2 vs. 27.7±0.8%, respectively, p<0.05). T3–15 mg/kg group showed reduction in VCAM-1, E-selectin, IL-6 and MMP-12 (3.9±1.9 vs. 28.5±3.1%; 10.3±0.5 vs. 59.8±8.5%; 2.6±1.7 vs. 14.0±1.7%; and 16.2±3.2 vs. 27.7 0.8%, respectively, p<0.05). In B2, T3–4 mg/kg group reduced aortic tissue expression of intercellular adhesion molecule 1 (ICAM-1), E-selectin, IL-6, MMP-12 and MMP-9 compared to T3-negative rabbits group (29.9±2.4 vs. 55.3±1.3%; 26.7±1.5 vs. 60.5±7.6%; 15.7±0.7 vs. 27.7±4.8%; 34.8±2.7 vs. 46.5±3.4%; and 25.89±3.9 vs. 45.9±1.7%, respectively, p<0.05). T3–15 mg/kg group showed reduced VCAM-1, ICAM-1, E-selectin, IL-6, MMP-12 and MMP-9 (20.5±3.3 vs. 35.6±2.5%; 24.9±1.3 vs. 55.3±1.3%; 29.9±6.7 vs. 60.5±7.6; 11.3±2.2 vs. 27.7±4.8%; 23.0±1.7 vs. 46.5±3.4%; and 17.6±1.9 vs. 45.9±1.7%, respectively, p<0.05. Conclusion These findings suggest the possible atheroprotective role T3 plays as an adjunct supplementation to standard treatment in the prevention of CAD.

Employing different types of phytoestrogens improve bone mineralization in bisphenol A stimulated osteoblast

Aims: Phytoestrogens and xenoestrogens act as agonists/antagonists in bone formation and differentiation. Strong bones are depending of the ability of osteoblasts to form new tissue and to mineralize the newly formed tissue. Dysfunctional or loss of mineralization leads to weak bone and increased fracture risk. In this study, we reported the effect of different types of phytoestrogens (daidzein, genistein and equol) on mineralization in hFOB 1.19 cells stimulated with bisphenol A (BPA). Main methods: Cell mineralization capacity of phytoestrogens was investigated by evaluating calcium, phosphate content and alkaline phosphatase activity. Bone related markers, osteocalcin and osteonectin, responsible in maintaining mineralization were also measured. Key findings: BPA is significantly interfering with bone mineralization in hFOB 1.19 cells. However, the enhanced mineralization efficacy of daidzein and genistein (particularly at a dose of 5 and 40 &mgr;g/mL, respectively) was evidenced by increasing calcium and phosphate content, higher ALP activity, compared to the untreated BPA group. The quantitative analyses were confirmed through morphological findings. Osteocalcin and osteonectin levels were increased in phytoestrogens‐treated cells. These findings revealed the potential effect of phytoestrogens in reverting the demineralization process due to BPA exposure in hFOB 1.19 cells. Significance: We found that osteoblast differentiation and mineralization were maintained following treatment with phytoestrogens under BPA exposure.

HIGH-DENSITY LIPOPROTEIN ATTENUATES SECRETION AND GENE EXPRESSION OF CELLULAR ADHESION MOLECULES AND PROINFLAMMATORY CYTOKINES IN LIPOPOLYSACCHARIDE-STIMULATED ENDOTHELIAL CELLS

This study was conducted to investigate the effects of high-density lipoprotein (HDL) on secretion and gene expression of intercellular adhesion molecules-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), endothelial-leukocyte adhesion molecule-1 (E-selectin), interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) by human vascular endothelial cells (HUVEC). Lipoploysacharides-stimulated HUVEC was incubated with different concentrations of HDL (20-120 mg/dL) for 16 hours. The levels of all biomarkers were measured by ELISA. Total RNA was extracted and all bioamarkers’ mRNA levels were measured by Taqman real-time polymerase chain reaction assay Different HDL concentrations reduced the secretion and expressonof all biomarkers except VCAM-1, which may contribute to the prevention and regression of atherosclerosis.

Effects of adding tocotrienol-tocopherol mixed fraction and vitamin C supplementation on coronary risk biomarkers in patients with hypercholesterolaemia with moderate coronary risk.

Article history: Received on: 07/01/2016 Revised on: 07/02/2016 Accepted on: 24/03/2016 Available online: 30/04/2016 This study was a prospective clinical trial to investigate the effects of adding combined tocotrienol-tocopherol mixed fraction (TTMF) and vitamin C (TTMF+C) supplementation on coronary biomarkers in non-statin and statin treated patients with hypercholesterolaemia (HC) with moderate coronary risk. A total of 35 patients were randomised at baseline into one of two groups, (G1) TTMF+C (320mg TTMF plus 500mg vitamin C) alone daily and (G2) TTMF+C (320mg TTMF plus 500mg vitamin C) plus atorvastatin 10 mg daily. The entire supplementation were taken for 12 months. Fasting serum samples were taken at baseline, 2weeks, 3months, 6months and 12months post-randomisation and analysed for inflammatory biomarkers; high sensitivity Creactive protein (hsCRP) and interleukin-6 (IL6). Combination of TTMF and vitamin C supplementation leads to neutral effects on lipid profiles and inflammation; with no added benefit in statin-treated HC patients with moderate coronary risk. This neutral effects may be attributed to the tocopherol composition in TTMF which could possibly attenuate any potential beneficial effects of tocotrienols. Clinical studies using pure tocotrienols in the absence of tocopherols would further confirm this.

930 PROTHROMBOGENESIS IN METABOLIC SYNDROME SUBJECTS WITH DIFFERENT GLYCAEMIC AND HYPERTENSIVE STATUS

Background: Coronary artery disease (CAD) is the leading cause of non-communicable disease mortality in developing countries such as Malaysia. Metabolic syndrome (MS) subjects are at high risk of developing atherosclerosis and CAD. Diabetes (DM) and hypertension (HT), two major coronary risk factors often co-exist in MS. The prothrombotic status of MS with different glycaemic status in the presence/ absence of newly diagnosed HT has not been well established. Objective: To compare the prothrombotic status of MS subjects with different glycaemic status with/ without HT and normotensive, normoglycaemic controls. Methods: 134 MS subjects (Age, mean±SD: 51.4 ± 8.4 years, 43 males and 96 females) were recruited and identified into (1) MS with hyperglycaemia (MSHG), n=58 and (2) MS without hyperglycaemia (MSNG), n=76. Each group was further divided into two sub-groups, (1) those with newly diagnosed HT and (2) normotension (NT). 45 subjects without MS and HT were recruited as controls (Age, mean+SD: 48.0+2.0 years, 16 males and 29 females). All groups were matched for age, gender and smoking status. The plasma levels of fibrinogen, tissue plasminogen activator (tPA) and homocysteine (Hcys) were measured. Results: There were no significant differences in plasma levels of fibrinogen, tPA or Hcys biomarkers between all MS and controls, between MS subgroups and between MS subgroups nad controls. Conclusion: These findings suggest that within the prothrombogenesis biomarkers studied, there was lack of enhanced prothrombogenesis in MS subjects with different glycaemic status in the presence/ absence of newly diagnosed HT.