OBJECTIVES: (1) To compare the concentrations of biomarkers of inflammation, endothelial activation and oxidative stress in subjects with low HDL-c compared to normal HDL-c; (2) To examine the association and correlation between HDL-c and these biomarkers and (3) To determine whether HDL-c is an independent predictor of these biomarkers.

METHODS: 422 subjects (mean age±SD = 43.2±11.9 years) of whom 207 had low HDL-c concentrations (HDL-c <1.0 mmol/L and <1.3 mmol/L for males and females respectively) and 215 normal controls (HDL-c ≥1.0 and ≥1.3 mmol/L for males and females respectively) were recruited in this study. The groups were matched for age, gender, ethnicity, smoking status, diabetes mellitus and hypertension. Fasting blood samples were collected for analysis of biomarkers of inflammation [high-sensitivity C-reactive protein (hsCRP) and Interleukin-6 (IL-6)], endothelial activation [soluble Vascular Cell Adhesion Molecule-1 (sVCAM-1), soluble Intercellular Adhesion Molecule-1 (sICAM-1) and E-selectin)] and oxidative stress [F2-Isoprostanes, oxidized Low Density Lipoprotein (ox-LDL) and Malondialdehyde (MDA)].

RESULTS: Subjects with low HDL-c had greater concentrations of inflammation, endothelial activation and oxidative stress biomarkers compared to controls. There were negative correlations between HDL-c concentration and biomarkers of inflammation (IL-6, p = 0.02), endothelial activation (sVCAM-1 and E-selectin, p = 0.029 and 0.002, respectively), and oxidative stress (MDA and F2-isoprostane, p = 0.036 and <0.0001, respectively). Multiple linear regression analysis showed HDL-c as an independent predictor of IL-6 (p = 0.02) and sVCAM-1 (p<0.03) after correcting for various confounding factors.

SUBJECTS: Female Dark Agouti (DA) rats.

METHODS: Three different dosages of (2 mg/kg of body weight, 3 mg/kg of body weight and 4 mg/kg of body weight) collagen and complete Freund's adjuvant suspension were tested. After 45 days, serum C-reactive protein, TNF-α, superoxide dismutase and total glutathione assays were done. Radiographic and histopathological changes in the joints were compared.

RESULTS: All three groups showed signs of arthritic changes, confirmed by histopathological and radiographic changes. Severe arthritic changes were seen in the rats injected with 4 mg/kg of body weight of collagen. There was a significant increase in C-reactive protein, TNF-α, super oxide dismutase and total glutathione levels in the plasma in arthritis rats and the changes were more significant with 4 mg/kg of collagen.

METHODS: Subjects were divided into two age groups-32 ± 2 (young) and 52 ± 2 (old) years old. Four subjects from each group were assigned with TRF (78% tocotrienol and 22% tocopherol, 150 mg/day) or placebo capsules for 6 months. Fasting plasma were obtained at 0, 3, and 6 months. Plasma tocopherol and tocotrienol levels were determined. Plasma proteome was resolved by 2DE, and differentially expressed proteins identified by MS. The expressions of three proteins were validated by Western blotting.

RESULTS: Six months of TRF supplementation significantly increased plasma levels of tocopherols and tocotrienols. Proteins identified as being differentially expressed were related to cholesterol homeostasis, acute-phase response, protease inhibitor, and immune response. The expressions of Apolipoprotein A-I precursor, Apolipoprotein E precursor, and C-reactive protein precursor were validated. The old groups showed more proteins changing in expression.

METHODOLOGY: A cross-sectional study involved 105 apparently healthy adults. Interview questionnaire was used to collect personal information. Participants were excluded if they suffered from acute or chronic inflammatory diseases, or continued using medicines, which might affect the biomedical results.

RESULTS: In association with increased Body Mass Index (BMI), the obese group displayed significant higher markers including: interleukin 6 (IL-6), high sensitivity C reactive protein (hs-CRP), total cholesterol (TC), systolic blood pressure (SBP), and diastolic blood pressure (DBP). Obese group in association with increased waist circumference (WC) was higher significantly in inflammatory markers (IL-6, hs-CRP), lipid profile (TC) and triglyceride (TG), and blood pressure (SBP, DBP). A tertile of a feature of systemic inflammation (hs-CRP) was created, by Ordinal Logistic Regression, after adjusting for the age, gender, smoking habits, physical activity pattern, father and mother's health history; risk factors were the increased BMI [OR: 1.24] (95% CI: 1.005-1.548, P=0.050), IL-6 [OR: 3.35] (95% CI: 1.341-8.398, P=0.010), DBP [OR: 1.19] (95% CI: 1.034-1.367, P=0.015), and reduced Adiponectin [OR: 0.59] (95% CI: 0.435-0.820, P=0.001). Finally, BMI correlated with IL-6 and hs-CRP (r=0.326, P=0.005; r=0.347, P<0.001; respectively), and hs-CRP correlated with IL-6 (r=0.303, P=0.010), and inversely with Adiponectin (r=-0.342, P=0.001).