Effect of thyroid function on LDL oxidation.

In this study, the effect of different levels of thyroid hormone and metabolic activity on low density lipoprotein (LDL) oxidation was investigated. Thus, in 16 patients with hyperthyroidism, 16 with hypothyroidism, and 16 age- and sex-matched healthy normolipidemic control subjects, the native LDL content in lipid peroxides, vitamin E, beta-carotene, and lycopene, as well as the susceptibility of these particles to undergo lipid peroxidation, was assessed. Hyperthyroidism was associated with significantly higher lipid peroxidation, as characterized by a higher native LDL content in lipid peroxides, a lower lag phase, and a higher oxidation rate than in the other two groups. This elevated lipid peroxidation was associated with a lower LDL antioxidant concentration. Interestingly, hypothyroid patients showed an intermediate behavior. In fact, in hypothyroidism, LDL oxidation was significantly lower than in hyperthyroidism but higher than in the control group. Hypothyroidism was also characterized by the highest beta-carotene LDL content, whereas vitamin E was significantly lower than in control subjects. In hyperthyroidism but not in the other two groups, LDL oxidation was strongly influenced by free thyroxine blood content. In fact in this group, the native LDL lipid peroxide content and the lag phase were directly and indirectly, respectively, related to free thyroxine blood levels. On the contrary, in hypothyroidism LDL oxidation was strongly and significantly related to serum lipids. In conclusion, both hypothyroidism and hyperthyroidism are characterized by higher levels of LDL oxidation when compared with normolipidemic control subjects. In hyperthyroid patients, the increased lipid peroxidation was strictly related to free thyroxine levels, whereas in hypothyroidism it was strongly influenced by serum lipids.

[1]  H. Esterbauer,et al.  Continuous Monitoring of in Vztro Oxidation of Human Low Density Lipoprotein , 2009 .

[2]  B. Staels,et al.  Growth hormone normalizes low-density lipoprotein receptor gene expression in hypothyroid rats. , 1996, Metabolism: clinical and experimental.

[3]  M. Triggiani,et al.  Oxidative structural modifications of low density lipoprotein in homozygous familial hypercholesterolemia. , 1995, Atherosclerosis.

[4]  F. Ursini,et al.  Direct measurement by single photon counting of lipid hydroperoxides in human plasma and lipoproteins. , 1995, Analytical biochemistry.

[5]  R. Maranhão,et al.  Evaluation of oxidative stress in patients with hyperlipidemia. , 1995, Atherosclerosis.

[6]  J. German,et al.  Older plasma lipoproteins are more susceptible to oxidation: a linking mechanism for the lipid and oxidation theories of atherosclerotic cardiovascular disease. , 1995, Proceedings of the National Academy of Sciences of the United States of America.

[7]  V. V. van Hinsbergh,et al.  Supplementation with low doses of vitamin E protects LDL from lipid peroxidation in men and women. , 1995, Arteriosclerosis, thrombosis, and vascular biology.

[8]  P. Ridker,et al.  Supplementation with β-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation , 1995 .

[9]  F. Cuccurullo,et al.  Vitamins E, C and lipid peroxidation in plasma and arterial tissue of smokers and non-smokers. , 1995, Atherosclerosis.

[10]  P. Reaven,et al.  Susceptibility of human LDL to oxidative modification. Effects of variations in beta-carotene concentration and oxygen tension. , 1994, Arteriosclerosis and thrombosis : a journal of vascular biology.

[11]  S. Grundy,et al.  Effect of combined supplementation with alpha-tocopherol, ascorbate, and beta carotene on low-density lipoprotein oxidation. , 1993, Circulation.

[12]  B. Frei,et al.  Mechanisms of copper- and iron-dependent oxidative modification of human low density lipoprotein. , 1993, Journal of lipid research.

[13]  P. Demacker,et al.  Oxidation resistance, oxidation rate, and extent of oxidation of human low-density lipoprotein depend on the ratio of oleic acid content to linoleic acid content: studies in vitamin E deficient subjects. , 1993, Free radical biology & medicine.

[14]  P. Reaven,et al.  Effect of dietary antioxidant combinations in humans. Protection of LDL by vitamin E but not by beta-carotene. , 1993, Arteriosclerosis and thrombosis : a journal of vascular biology.

[15]  B. Lee,et al.  High-performance liquid chromatographic method for routine determination of vitamins A and E and β-carotene in plasma , 1992 .

[16]  H. Esterbauer,et al.  The role of lipid peroxidation and antioxidants in oxidative modification of LDL. , 1992, Free radical biology & medicine.

[17]  A. Shoji,et al.  Evaluation of adriamycin-induced lipid peroxidation , 1992 .

[18]  B. Weintraub,et al.  Spectrum of subclinical and overt hypothyroidism: effect on thyrotropin, prolactin, and thyroid reserve, and metabolic impact on peripheral target tissues. , 1992, The American journal of medicine.

[19]  F. Kok,et al.  Supplementation with vitamin E but not beta-carotene in vivo protects low density lipoprotein from lipid peroxidation in vitro. Effect of cigarette smoking. , 1992, Arteriosclerosis and thrombosis : a journal of vascular biology.

[20]  F. Ursini,et al.  Effect of dietary monounsaturated and polyunsaturated fatty acids on the susceptibility of plasma low density lipoproteins to oxidative modification. , 1992, Arteriosclerosis and thrombosis : a journal of vascular biology.

[21]  R. Cohen,et al.  Oxidized low density lipoproteins cause contraction and inhibit endothelium-dependent relaxation in the pig coronary artery. , 1990, The Journal of clinical investigation.

[22]  H. Esterbauer,et al.  Biochemical, structural, and functional properties of oxidized low-density lipoprotein. , 1990, Chemical research in toxicology.

[23]  J L Witztum,et al.  Beyond cholesterol. Modifications of low-density lipoprotein that increase its atherogenicity. , 1989, The New England journal of medicine.

[24]  K. Asayama,et al.  Lipid peroxidation and free radical scavengers in thyroid dysfunction in the rat: a possible mechanism of injury to heart and skeletal muscle in hyperthyroidism. , 1987, Endocrinology.

[25]  M. Paller,et al.  Hypothyroidism protects against free radical damage in ischemic acute renal failure. , 1986, Kidney international.

[26]  A. Swaroop,et al.  Heat exposure and hypothyroid conditions decrease hydrogen peroxide generation in liver mitochondria. , 1985, The Biochemical journal.

[27]  K. Ingold,et al.  beta-Carotene: an unusual type of lipid antioxidant. , 1984, Science.

[28]  J. Kane,et al.  Contribution of carotenoids to the optical activity of human serum low-density lipoprotein. , 1974, Biochemistry.

[29]  Oliver H. Lowry,et al.  Protein measurement with the Folin phenol reagent. , 1951, The Journal of biological chemistry.

[30]  P. Ridker,et al.  Supplementation with beta-carotene in vivo and in vitro does not inhibit low density lipoprotein oxidation. , 1995, Atherosclerosis.

[31]  R. Curi,et al.  Control of superoxide dismutase, catalase and glutathione peroxidase activities in rat lymphoid organs by thyroid hormones. , 1994, The Journal of endocrinology.

[32]  O. Eber,et al.  [Beta-carotene, vitamin A and carrier proteins in thyroid diseases]. , 1993, Acta medica Austriaca.

[33]  T. Horie,et al.  Evaluation of adriamycin-induced lipid peroxidation. , 1992, Biochemical pharmacology.

[34]  F. Kok,et al.  In vivo supplementation of vitamin E, but not of ß-carotene protects LDL to in vitro lipid peroxidation. Effect of cigarette smoking. , 1992 .

[35]  D. Steinberg,et al.  Role of oxidised low density lipoprotein in atherogenesis. , 1993, British heart journal.

[36]  N. Krinsky,et al.  Characterization of products formed during the autoxidation of β-carotene , 1991 .

[37]  U. Steinbrecher,et al.  Role of oxidatively modified LDL in atherosclerosis. , 1990, Free radical biology & medicine.

[38]  K. Asayama,et al.  Oxidative muscular injury and its relevance to hyperthyroidism. , 1990, Free radical biology & medicine.

[39]  H. Esterbauer,et al.  Continuous monitoring of in vitro oxidation of human low density lipoprotein. , 1989, Free radical research communications.

[40]  H. Miwa,et al.  High-performance liquid chromatographic analysis of serum short-chain fatty acids by direct derivatization. , 1987, Journal of chromatography.

[41]  J. Hokanson,et al.  Single vertical spin density gradient ultracentrifugation. , 1986, Methods in enzymology.

[42]  J. Hokanson,et al.  [8] Single vertical spin density gradient ultracentrifugation , 1986 .

[43]  C. Dillard,et al.  Fluorescent damage products of lipid peroxidation. , 1984, Methods in enzymology.

[44]  C. Dillard,et al.  [41] Fluorescent damage products of lipid peroxidation , 1984 .