| In vivo: |
| J Lipid Res. 2000 Nov;41(11):1883-9. | | Hyperabsorption and retention of campestanol in a sitosterolemic homozygote: comparison with her mother and three control subjects.[Pubmed: 11060358] |
METHODS AND RESULTS:
We measured the percent absorption, turnover, and distribution of Campestanol (24-methyl-5alpha-cholestan-3beta-ol) in a sitosterolemic homozygote, her obligate heterozygous mother, and three healthy human control subjects. For reasons relating to sterol hyperabsorption, the homozygote consumed a diet low in plant sterols that contained Campestanol at about 2 mg/day. The heterozygote and three control subjects were fed a diet supplemented with a spread that contained Campestanol at 540 mg/day and sitostanol (24-ethyl-5alpha-cholestan-3beta-ol) at 1.9 g/day as fatty acid esters. Plasma Campestanol concentrations determined by capillary gas-liquid chromatography were 0.72 +/- 0.03 mg/dl in the homozygote, 0.09 +/- 0.04 mg/dl in the heterozygote, and 0.05 +/- 0.03 mg/dl for the control mean. After simultaneous pulse labeling with [3alpha-(3)H]Campestanol intravenously and [23-(14)C]Campestanol orally, the maximum percent absorption measured by the plasma dual-isotope ratio method as a single time point was 80% in the homozygote, 14.3% in the heterozygote, and 5.5 +/- 4.3% as the mean for three control subjects. Turnover (pool size) values estimated by mathematical analysis of the specific activity versus time [3alpha-(3)H]Campestanol decay curves were as follows: 261 mg in the homozygote, 27.3 mg in the heterozygote, and 12.8 +/- 7.6 mg in the three control subjects (homogygote vs. controls, P < 0.001). The calculated production rate (mg/24 h) equivalent to actual absorption in the presence of dietary sterols and stanols was 0.67 mg/day or 31% of intake in the homozygote, 2.1 mg/day or 0.3% of intake in the heterozygote, and 0.7 +/- 0.3 mg/day or 0.1% of intake in the three control subjects. However, the excretion constant from pool A (K(A)) was prolonged markedly in the homozygote, but was 100 times more rapid in the heterozygote and three control subjects.
CONCLUSIONS:
Thus, Campestanol, like other noncholesterol sterols, is hyperabsorbed and retained in sitosterolemic homozygotes. However, Campestanol absorption was only slightly increased in the sitosterolemic heterozygote and removal was as rapid as in control subjects. | | Lipids. 2005 Sep;40(9):919-23. | | Dietary sitostanol and campestanol: accumulation in the blood of humans with sitosterolemia and xanthomatosis and in rat tissues.[Pubmed: 16331855] | Dietary sitostanol has a hypocholesterolemic effect because it decreases the absorption of cholesterol. However, its effects on the sitostanol concentrations in the blood and tissues are relatively unknown, especially in patients with sitosterolemia and xanthomatosis. These patients hyperabsorb all sterols and fail to excrete ingested sitosterol and other plant sterols as normal people do. The goal of the present study was to examine the absorbability of dietary sitostanol in humans and animals and its potential long-term effect.
METHODS AND RESULTS:
Two patients with sitosterolemia were fed the margarine Benecol (McNeill Nutritionals, Ft. Washington, PA), which is enriched in sitostanol and Campestanol, for 7-18 wk. Their plasma cholesterol levels decreased from 180 to 167 mg/dL and 153 to 113 mg/dL, respectively. Campesterol and sitosterol also decreased. However, their plasma sitostanol levels increased from 1.6 to 10.1 mg/dL and from 2.8 to 7.9 mg/dL, respectively. Plasma Campestanol also increased. After Benecol withdrawal, the decline in plasma of both sitostanol and Campestanol was very sluggish. In an animal study, two groups of rats were fed high-cholesterol diets with and without sitostanol for 4 wk. As expected, plasma and liver cholesterol levels decreased 18 and 53%, respectively. The sitostanol in plasma increased fourfold, and sitostanol increased threefold in skeletal muscle and twofold in heart muscle. Campestanol also increased significantly in both plasma and tissues.
CONCLUSIONS:
Our data indicate that dietary sitostanol and Campestanol are absorbed by patients with sitosterolemia and xanthomatosis and also by rats. The absorbed plant stanols were deposited in rat tissues. Once absorbed by sitosterolemic patients, the prolonged retention of sitostanol and Campestanol in plasma might increase their atherogenic potential. |
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