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Michael Aviram

Bio: Michael Aviram is an academic researcher from Technion – Israel Institute of Technology. The author has contributed to research in topics: Cholesterol & Lipoprotein. The author has an hindex of 94, co-authored 479 publications receiving 31141 citations. Previous affiliations of Michael Aviram include University of Tromsø & Steward Health Care System.


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Journal ArticleDOI
TL;DR: It is concluded that HDL-associated PON possesses peroxidase-like activity that can contribute to the protective effect of PON against lipoprotein oxidation, and may be a major contributor to the antiatherogenicity of this lipop Protein.
Abstract: HDL levels are inversely related to the risk of developing atherosclerosis. In serum, paraoxonase (PON) is associated with HDL, and was shown to inhibit LDL oxidation. Whether PON also protects HDL from oxidation is un- known, and was determined in the present study. In hu- mans, we found serum HDL PON activity and HDL sus- ceptibility to oxidation to be inversely correlated ( r 2 5 0.77, n 5 15). Supplementing human HDL with purified PON in- hibited copper-induced HDL oxidation in a concentration- dependent manner. Adding PON to HDL prolonged the ox- idation lag phase and reduced HDL peroxide and aldehyde formation by up to 95%. This inhibitory effect was most pronounced when PON was added before oxidation initia- tion. When purified PON was added to whole serum, essen- tially all of it became HDL-associated. The PON-enriched HDL was more resistant to copper ion-induced oxidation than was control HDL. Compared with control HDL, HDL from PON-treated serum showed a 66% prolongation in the lag phase of its oxidation, and up to a 40% reduction in per- oxide and aldehyde content. In contrast, in the presence of various PON inhibitors, HDL oxidation induced by either copper ions or by a free radical generating system was markedly enhanced. As PON inhibited HDL oxidation, two major functions of HDL were assessed: macrophage choles- terol efflux, and LDL protection from oxidation. Compared with oxidized untreated HDL, oxidized PON-treated HDL caused a 45% increase in cellular cholesterol efflux from J-774 A.1 macrophages. Both HDL-associated PON and purified PON were potent inhibitors of LDL oxidation. Searching for a possible mechanism for PON-induced inhibition of HDL oxidation revealed PON (2 paraoxonase U/ml)-mediated hydrolysis of lipid peroxides (by 19%) and of cholesteryl linoleate hydroperoxides (by 90%) in oxidized HDL. HDL-associated PON, as well as purified PON, were also able to substantially hydrolyze (up to 25%) hydrogen peroxide (H 2 O 2 ), a major reactive oxygen species produced under oxidative stress during atherogenesis. Finally, we an- alyzed serum PON activity in the atherosclerotic apolipo- protein E-deficient mice during aging and development of atherosclerotic lesions. With age, serum lipid peroxidation and lesion size increased, whereas serum PON activity de- creased. We thus conclude that HDL-associated PON possesses peroxidase-like activity that can contribute to the protective effect of PON against lipoprotein oxidation. The presence of PON in HDL may thus be a major contributor to the anti- atherogenicity of this lipoprotein. ( J. Clin. Invest. 1998. 101: 1581-1590.) Key words: paraoxonaseHDLLDLlipid peroxidationapolipoprotein E deficient mice

1,167 citations

Journal ArticleDOI
TL;DR: Pomegranate juice had potent antiatherogenic effects in healthy humans and in atherosclerotic mice that may be attributable to its antioxidative properties.

847 citations

Journal ArticleDOI
TL;DR: The antioxidant effect of dietary red wine on plasma lipid peroxidation was not secondary to changes in the plasma vitamin E or beta-carotene content but could be related to the elevation of polyphenol concentration in plasma and LDL.

667 citations

Journal ArticleDOI
TL;DR: Although in vitro antioxidant potency does not prove in vivo biological activity, there is also consistent clinical evidence of antioxidant potency for the most potent beverages including both PJ and red wine.
Abstract: A number of different beverage products claim to have antioxidant potency due to their perceived high content of polyphenols. Basic and applied research indicates that pomegranate juice (PJ), produced from the Wonderful variety of Punica granatum fruits, has strong antioxidant activity and related health benefits. Although consumers are familiar with the concept of free radicals and antioxidants, they are often misled by claims of superior antioxidant activity of different beverages, which are usually based only on testing of a limited spectrum of antioxidant activities. There is no available direct comparison of PJ’s antioxidant activity to those of other widely available polyphenol-rich beverage products using a comprehensive variety of antioxidant tests. The present study applied (1) four tests of antioxidant potency [Trolox equivalent antioxidant capacity (TEAC), total oxygen radical absorbance capacity (ORAC), free radical scavenging capacity by 2,2-diphenyl-1-picrylhydrazyl (DPPH), and ferric reduci...

631 citations

Journal ArticleDOI
TL;DR: PON's ability to protect LDL against oxidation is accompanied by inactivation of the enzyme, suggesting the interaction of oxidized lipids in Ox-LDL with the PON's free sulfhydryl group.

621 citations


Cited by
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[...]

08 Dec 2001-BMJ
TL;DR: There is, I think, something ethereal about i —the square root of minus one, which seems an odd beast at that time—an intruder hovering on the edge of reality.
Abstract: There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality. Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

33,785 citations

Journal ArticleDOI
TL;DR: The nature and contents of the various polyphenols present in food sources and the influence of agricultural practices and industrial processes are reviewed, and bioavailability appears to differ greatly between the variousPolyphenols, and the most abundantpolyphenols in the authors' diet are not necessarily those that have the best bioavailability profile.

6,842 citations

Journal ArticleDOI
TL;DR: An overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, is offered, as well as a brief description of the chemistry ofpolyphenols and their occurrence in plant foods.
Abstract: Polyphenols constitute one of the most numerous and ubiquitous groups of plant metabolites and are an integral part of both human and animal diets. Ranging from simple phenolic molecules to highly polymerized compounds with molecular weights of greater than 30,000 Da, the occurrence of this complex group of substances in plant foods is extremely variable. Polyphenols traditionally have been considered antinutrients by animal nutritionists, because of the adverse effect of tannins, one type of polyphenol, on protein digestibility. However, recent interest in food phenolics has increased greatly, owing to their antioxidant capacity (free radical scavenging and metal chelating activities) and their possible beneficial implications in human health, such as in the treatment and prevention of cancer, cardiovascular disease, and other pathologies. Much of the literature refers to a single group of plant phenolics, the flavonoids. This review offers an overview of the nutritional effects of the main groups of polyphenolic compounds, including their metabolism, effects on nutrient bioavailability, and antioxidant activity, as well as a brief description of the chemistry of polyphenols and their occurrence in plant foods.

3,821 citations

Journal ArticleDOI
TL;DR: The histological classification of human atherosclerotic lesions found in the second part of this report led to the earlier definitions of precursor lesions, and the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes was attempted.
Abstract: This report is the continuation of two earlier reports that defined human arterial intima and precursors of advanced atherosclerotic lesions in humans. This report describes the characteristic components and pathogenic mechanisms of the various advanced atherosclerotic lesions. These, with the earlier definitions of precursor lesions, led to the histological classification of human atherosclerotic lesions found in the second part of this report. The Committee on Vascular Lesions also attempted to correlate the appearance of lesions noted in clinical imaging studies with histological lesion types and corresponding clinical syndromes. In the histological classification, lesions are designated by Roman numerals, which indicate the usual sequence of lesions progression. The initial (type I) lesion contains enough atherogenic lipoprotein to elicit an increase in macrophages and formation of scattered macrophage foam cells. As in subsequent lesion types, the changes are more marked in locations of arteries with adaptive intimal thickening. (Adaptive thickenings, which are present at constant locations in everyone from birth, do not obstruct the lumen and represent adaptations to local mechanical forces). Type II lesions consist primarily of layers of macrophage foam cells and lipid-laden smooth muscle cells and include lesions grossly designated as fatty streaks. Type III is the intermediate stage between type II and type IV (atheroma, a lesion that is potentially symptom-producing). In addition to the lipid-laden cells of type II, type III lesions contain scattered collections of extracellular lipid droplets and particles that disrupt the coherence of some intimal smooth muscle cells. This extracellular lipid is the immediate precursor of the larger, confluent, and more disruptive core of extracellular lipid that characterizes type IV lesions. Beginning around the fourth decade of life, lesions that usually have a lipid core may also contain thick layers of fibrous connective tissue (type V lesion) and/or fissure, hematoma, and thrombus (type VI lesion). Some type V lesions are largely calcified (type Vb), and some consist mainly of fibrous connective tissue and little or no accumulated lipid or calcium (type Vc).

3,698 citations

Journal ArticleDOI
TL;DR: A comprehensive and critical review of the in vivo data on resveratrol is provided, and its potential as a therapeutic for humans is considered.
Abstract: Resveratrol, a constituent of red wine, has long been suspected to have cardioprotective effects. Interest in this compound has been renewed in recent years, first from its identification as a chemopreventive agent for skin cancer, and subsequently from reports that it activates sirtuin deacetylases and extends the lifespans of lower organisms. Despite scepticism concerning its bioavailability, a growing body of in vivo evidence indicates that resveratrol has protective effects in rodent models of stress and disease. Here, we provide a comprehensive and critical review of the in vivo data on resveratrol, and consider its potential as a therapeutic for humans.

3,509 citations