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Increased plasma 7 beta-hydroxycholesterol concentrations in a population with a high risk for cardiovascular disease
B Ziedén1, A Kaminskas, M Kristenson
1Department of Physiology and Biochemistry, Faculty of Medicine, Vilnius, Lithuania. Bo.Zieden@kfc.liu.se
Insights
Lithuanian men have higher coronary heart disease mortality due to increased lipid peroxidation, indicated by higher plasma 7 beta-hydroxycholesterol and lower LDL oxidation resistance compared to Swedish men.
Area of Science:
- Cardiovascular Health
- Oxidative Stress Research
- Nutritional Epidemiology
Background:
- Coronary heart disease (CHD) mortality significantly higher in Lithuanian men (50-54 years) vs. Swedish men.
- Traditional risk factors do not fully explain this disparity.
- Lower antioxidant levels (gamma-tocopherol, lycopene, beta-carotene) noted in Lithuanian men.
Purpose of the Study:
- Investigate plasma oxysterol concentrations in Lithuanian and Swedish men.
- Assess differences in LDL oxidation resistance and related biomarkers.
- Determine if oxysterol levels correlate with oxidative stress markers.
Main Methods:
- Plasma oxysterols (specifically 7 beta-hydroxycholesterol) measured in men from Lithuania and Sweden.
- Low-density lipoprotein (LDL) oxidation lag time determined.
- Plasma concentrations of gamma-tocopherol, lycopene, beta-carotene, and LDL linoleic acid analyzed.
Main Results:
- Higher plasma 7 beta-hydroxycholesterol in Lithuanian men (12+/-5 ng/mL) vs. Swedish men (9+/-8 ng/mL).
- Shorter LDL oxidation lag time (75+/-14 min) in Lithuanian men vs. Swedish men (90+/-13 min).
- Lower LDL linoleic acid and lipid-corrected gamma-tocopherol in Lithuanian men.
Conclusions:
- Elevated 7 beta-hydroxycholesterol in Lithuanian men suggests increased in vivo lipid peroxidation.
- Findings indicate enhanced oxidative stress may contribute to higher CHD mortality in Lithuanian men.
- Oxysterol profiles offer insights into population-specific cardiovascular disease risk factors.
Abstract:
The mortality in coronary heart disease among 50- to 54-year-old men is 4 times higher in Lithuania than in Sweden. It was recently suggested that traditional risk factors could not explain this mortality difference. LDL of Lithuanian men showed, however, a lower resistance to oxidation than that of Swedish men. In addition, the plasma concentration of gamma-tocopherol, lycopene, and beta-carotene were lower in Lithuanian men. In the present investigation, we determined plasma oxysterols in men from Lithuania and Sweden and found that the plasma concentration of 7 beta-hydroxycholesterol was higher in Lithuanian men, 12+/-5 versus 9+/-8 (SD) ng/mL (P=0.0011). This oxysterol is a cholesterol autoxidation product and there is no indication that it should have an enzymatic origin. Mean LDL oxidation lag time was shorter in Lithuanian men (75+/-14 versus 90+/-13 minutes, P<0.0001) and the concentration of LDL linoleic acid was lower (249+/-56 versus 292+/-54 microgram/mg of LDL protein, P<0.0001). Lipid corrected gamma-tocopherol was 0.07+/-0.02 mg/mL in Vilnius men and 0.12+/-0. 04 mg/mL (P<0.0001) in Linköping men. There was a negative correlation between the concentration of 7 beta-hydroxycholesterol and lag time (R=-0.31, P=0.0023). It is suggested that the higher 7 beta-hydroxycholesterol concentration in Lithuanian men is an indication of an increased in vivo lipid peroxidation.