Blunted nocturnal fall in blood pressure and oxidative stress in men and women with essential hypertension.
Low-density lipoprotein oxidation and antioxidant vitamins E and C were investigated in dipper (nocturnal blood pressure fall > 10%) and nondipper (nocturnal blood pressure fall < 10%) hypertensives. We studied 40 dippers and 28 nondippers balanced for gender, age, and body mass index. Blood samples were drawn for lipid profile determination, assessment of thiobarbituric acid-reactive substances, and fluorescent products of lipid peroxidation in native low-density lipoprotein, evaluation of susceptibility to low-density lipoprotein oxidation in vitro (lag phase and propagation rate), and determination of low-density lipoprotein vitamin E and plasma vitamins E and C contents. Compared with dippers, nondippers had significantly higher thiobarbituric acid-reactive substances and fluorescent products of lipid peroxidation (0.63 +/- 0.1 v 0.77 +/- 0.08 nmol malondialdehyde/mg low-density lipoprotein protein, and 14.5 +/- 6 v 17.9 +/- 4 units of relative fluorescence/mg low-density lipoprotein protein, respectively, both P < .05), shorter lag phase (56 +/- 13 v 49 +/- 9 min, P < .05), and lower plasma vitamin C content (42 +/- 9 v 35 +/- 10 micromol/L, P < .05). When gender was taken into account, differences were not significant between dipper and nondipper men, whereas, compared with dipper women, nondipper women showed significantly higher thiobarbituric acid-reactive substances and fluorescent products of lipid peroxidation (0.56 +/- 0.1 v 0.77 +/- 0.07 nmol malondialdehyde/mg low-density lipoprotein protein, and 12.5 +/- 4 v 17.5 +/- 4.6 units of relative fluorescence/mg low-density lipoprotein protein, respectively, both P < .05), shorter lag phase (62.5 +/- 11 v 49 +/- 9.5 min, P < .05), and lower plasma vitamin C content (44.9 +/- 10 v 34.7 +/- 10.8 micromol/L, P < .05). Given the role of low-density lipoprotein oxidation in the pathogenesis of atherosclerosis and that of vitamin C in protecting against it, our data suggest that nondippers, especially among women, show higher atherogenic risk than dippers.
Pierdomenico
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SD
Centro per lo Studio dell'Ipertensione Arteriosa, delle Dislipidemie e dell'Arteriosclerosi, Dipartimento di Medicina e Scienze dell'Invecchiamento, University G. D'Annunzio, Chieti, Italy. pierdomenico@unich.it
Costantini
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F
Bucci
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A
De Cesare
D
D
Bucciarelli
T
T
Cuccurullo
F
F
Mezzetti
A
A
D000328:Adult; D001205:Ascorbic Acid / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D001794:Blood Pressure / Q000502:physiology*; D018660:Blood Pressure Monitoring, Ambulatory; D002784:Cholesterol / Q000097:blood; D008078:Cholesterol, LDL / Q000097:blood; D002940:Circadian Rhythm; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood / Q000503:physiopathology*; D015227:Lipid Peroxidation; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014280:Triglycerides / Q000097:blood; D014810:Vitamin E / Q000097:blood
D001786:Blood Glucose; D008078:Cholesterol, LDL; D017392:Thiobarbituric Acid Reactive Substances; D014280:Triglycerides; D014810:Vitamin E; D002784:Cholesterol; D001205:Ascorbic Acid