Date of Completion
Maria Luz Fernandez, Hedley C. Freake, Ock Chun
Field of Study
Master of Science
Low plasma HDL cholesterol (HDL-c) has been recognized as a biomarker of cardiovascular disease (CVD) and diabetes. Also, low HDL-c is one of the characteristics of metabolic syndrome (MetS).
Objective: To assess whether low HDL-c and/or low HDL functionality are associated with higher risk for CVD in subjects classified with MetS.
Methods: Forty-subjects with MetS (11 men /29 women, 52.4 ± 9.5 years participated in the study. Anthropometric data [weight, height, BMI, waist circumference (WC), blood pressure (BP)], fasting plasma biomarkers [lipids, glucose, liver enzymes: alanine aminotransferase (ALT), and aspartate aminotransferase (AST), plasma insulin, and glycosylated hemoglobin (HbA1c)], biomarkers of oxidative stress and inflammation, and biomarkers of antioxidants status [glutathione peroxidase (GPx), superoxide dismutase (SOD), catalase, and total antioxidant capacity (TAC)] were measured. Lipoproteins particles were measured to identify the size and number. Also, the functionality of HDL was further assessed by measuring plasma apolipoproteins, paraoxonase-1(PON-1) and serum amyloid A1 (SAA1).
Results: Participants had a mean BMI of 32.3 ± 2.7 kg/m2 (29.8 – 39.3 kg/m2)placing the majority in the obesity category. In terms of MetS characteristics, all subjects (100%) fit the criteria for WC; 63% either had high systolic BP, high diastolic BP, or both; 70% were hyperglycemic; 48% had elevated plasma triglycerides (TG), and 43% had low HDL-c. We divided the subjects into two categories, Low HDL-c (men < 40 mg/dL and women < 50 mg/dL) (n = 17) and Normal HDL-c (men ≥ 40 mg/dL and women ≥ 50 mg/dL) (n = 23). Those with Low HDL-c had higher systolic BP (129.9 ± 9.7 vs 121.2 ± 14.2 mm Hg, p < 0.05), higher TG (166.6 ± 8.0 vs 115.5 ± 56.8 mg/dl, p < 0.05), and lower TAC (1.23 ± 0.9 vs 2.09 ± 1.5 mM Trolox equivalents, p < 0.05). In addition, strong negative correlations were found between HDL-c concentrations and each of the following parameters: WC (r= - 0.418, p < 0.01), insulin (r=-0.413, p < 0.05) and ALT (r = -0.324, p < 0.05). Lipoprotein data showed that large VLDL, medium VLDL, and small LDL particles were significantly higher in the Low HDL-c group (9.4 ± 6 vs 5.6 ± 4.4 nmol/L, p < 0.05), (25.1 ± 11.3 vs 15.8 ± 8.2 nmol/L, p < 0.01), (822.5 ± 283 vs 522.4 ± 288.2 nmol/L, p < 0.01), respectively. Both large and total HDL particles were higher in the Normal HDL-c group (8.2 ± 4.1 vs 4.3 ± 1.9 µmol/L, p < 0.01), (37.5 ± 4.4 vs 30.8 ± 4.8 µmol/L, p < 0.01), respectively. Apo A-I was significantly higher in Normal HDL-c group (985.4 ± 274.2 vs 790.7 ± 188.1 mg/L, p < 0.05). Also, Apo A-I was positively correlated with total HDL (r = 0.671, p < 0.01) and large HDL particles (r = 0.530, p < 0.01), respectively. PON-1 activity was significantly higher in the Normal HDL-c group (26.7 ± 14.1 vs 12.4 ± 16.1 U/ml, p< 0.05).
Conclusion: These data suggest that in these men and women with MetS, measuring both HDL-c concentrations and HDL particles can provide important information about levels and functionality of the protective HDL. In regards to plasma HDL-c, subjects with Low HDL-c appeared to have higher risk for CVD including dyslipidemia, hypertension, and higher concentrations for more atherogenic lipoproteins. Further, TAC, Apo A-I and PON-1 activity were lower among this group. These results confirm that individuals with Low HDL-c and MetS have increased risk for CVD.
ALYousef, Hana M., "Low Plasma HDL Cholesterol is Associated with Greater Risk for Cardiovascular Disease in Subjects with Metabolic Syndrome" (2018). Master's Theses. 1301.
Maria Luz Fernandez