Study on effects of resveratrol and quercetin on inflammation and insulin resistance

Boston University Medical Center ^ | December 23, 2010 | Unknown

[decimon]

A study was carried out to examine the extent to which quercetin and trans-resveratrol (RSV) prevented inflammation or insulin resistance in primary cultures of human adipocytes treated with tumor necrosis factor-a (TNF-a)—an inflammatory cytokine elevated in the plasma and adipose tissue of obese, diabetic individuals. Cultures of human adipocytes were pretreated with quercetin and trans-RSV followed by treatment with TNF-a. Subsequently, gene and protein markers of inflammation and insulin resistance were measured. The authors report that quercetin, and to a lesser extent trans-RSV, attenuated the TNF-a–induced expression of inflammatory genes such as interleukin (IL)-6, IL-1b, IL-8, and monocyte chemoattractant protein-1 (MCP-1) and the secretion of IL-6, IL-8, and MCP-1.

Forum members were concerned about certain aspects of the study, especially the extrapolation of in vitro results to in vivo situations. The in vitro conditions the authors describe are minimally representative of an in vivo condition. In vivo, after consumption of quercetin or resveratrol, these compounds undergo extensive metabolism, leading to glucuronidated, sulphated or methylated compounds. In a previous study, quercetin 3-glucoside was transformed to 3,4-dihydroxyphenylacetic acid, acetate and butyrate in cells from human gut; only 3'-methylquercetin has been detected in human plasma, present at a concentration of 0.1 to 0.2 µM after 3 h. The authors of the current paper are using concentrations up to 60 µM, concentrations which have not been found in vivo.

There were also concerns with the work on cell uptake of quercetin and resveratrol. Primary adipocytes were incubated with the polyphenols, but it is not clear whether or not the concentrations used were subtoxic. Our current knowledge is limited about local concentration of the molecules we are studying in subcellular compartments, their interaction with alternative targets, and eventually their transformation into products that could be more or less active on a given specific pathway. The real difficult and important issue is the identification of a reasonable convergence -- if not agreement -- between data originating from extremely distant approaches. In this case, the notion that metabolic diseases are related to a homeostatic imbalance in adipose tissue, linked to a different redox status, linked to activation of specific pathways, and that different redox sensitive polyphenols do have a protective effect, encompasses the evidence produced by extremely distant approaches.

From a clinical point of view, the role of phytochemicals acting as antioxidants and anti-inflammatory agents could be extremely important in inflammation-associated chronic conditions such as cardiovascular disease, diabetes, and cancer. Quercetin and resveratrol may indeed play an important role in this regard, and need to be investigated further to establish the clinical importance of natural dietary compounds in the prevention of chronic degenerative conditions.

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Contributions to this critique by the International Scientific Forum on Alcohol Research were provided by the following members:

David Vauzour, PhD Dept. of Food and Nutritional Sciences The University of Reading, UK

Fulvio Ursini, MD Dept. of Biological Chemistry University of Padova Padova, Italy

David Van Velden, MD Dept. of Pathology Stellenbosch University Stellenbosch, South Africa

Andrew L. Waterhouse, PhD Marvin Sands Professor Department of Viticulture and Enology University of California, Davis

Federico Leighton, MD Laboratorio de Nutricion Molecular Facultad de Ciencias Biologicas Universidad Catolica de Chile Santiago, Chile

R. Curtis Ellison, MD Section of Preventive Medicine & Epidemiology Boston University School of Medicine Boston, MA, USA

Harvey Finkel, MD Hematology/Oncology Boston University Medical Center Boston, MA, USA

For the detailed critique of this paper by the International Scientific Forum on Alcohol Research, go to www.bu.edu/alcohol-forum and click on Recent Reports.

The specialists who are members of the Forum are happy to respond to questions from Health Editors regarding emerging research on alcohol and health and will offer an independent opinion in context with other research on the subject.

Contacts for Editors

Professor R Curtis Ellison ellison@bu.edu Tel: : +1 508 333-1256

Helena Conibear helena@alcohol-forum4profs.org Tel +44 1300 341601 or + 44 7876 593 345

[decimon]

In vivo, veritas.

[decimon]

Chemoattractant ping.

[Durus]

There is truth in what? Vivo?

[decimon]

There is truth in what? Vivo?

You can't take literally my potshots at humor. The article discussed the problem with extrapolating in vitro results to in vivo effect.

[sipwine]

Bottom Line...sip wine:)

[dagogo redux]

From one in the field: Note that the end result from EVERY frickin’ scientific study is the dodge and funding/grant-plea that more study needs to be done.

No conclusion or finding is more important than the justification to take more of somebody’s money to do further research, and the result of that further research will be a further justification for yet more funding.

[grey_whiskers]

What's the point of using 60μmolar concentrations, when such a quantity is never found in vivo? Are they attempting to mimic the overdosing approach used to assess toxicity, but looking for salubrious effects?

Cheers!

[neverdem]

From one in the field: Note that the end result from EVERY frickin’ scientific study is the dodge and funding/grant-plea that more study needs to be done.

No conclusion or finding is more important than the justification to take more of somebody’s money to do further research, and the result of that further research will be a further justification for yet more funding.

dagogo redux, what are researchers supposed to do, just be content in their ignorance of a subject? Here's it's cell signaling, immunology and diabetes. I doubt the final word is in, in any of those fields, IMHO. If you can't freely access the original article, then it was not funded by the feds, IIRC.

Quercetin is equally or more effective than resveratrol in attenuating tumor necrosis factor-{alpha}-mediated inflammation and insulin resistance in primary human adipocytes.

Kidney disease patients: Eat your veggies, reward your kidneys

FReepmail me if you want on or off the diabetes or immunology ping lists.

[Quix]

THX THX.

[bvw]

Any one have some suggestions on dealing with a glioblastoma?

[decimon]

Any one have some suggestions on dealing with a glioblastoma?

I have nothing to offer but my best wishes for you or whomever.

[dagogo redux]

“dagogo redux, what are researchers supposed to do”

Oh, don’t get me wrong - researchers are supposed to do research: endlessly - and for that they always need someone else’s money: endlessly. I know the game, the endless game.

[bvw]

Thanks, it’s the diagnosis of a friend. There seems to have been a lot of legitimate progress in the past ten-twenty years towards an effective counter-attack on that quickly fatal type of cancer, I was just wondering if any Freeper knew of any best-hope type new treatment.

[cycjec]

I’m trying to add the keywords “chronicinflammation”
and “TNFalpha” but can’t seem to do it.

[cycjec]

The “add keyword” link suddenly appeared, ignore my
earlier.