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A number of studies have asserted that moderate drinking has a positive benefit on cardiovascular health. Now, scientists at the University of Rochester Medical Center have discovered how alcohol consumption can help to prevent heart disease. The research, published in the journal Arteriosclerosis, Thrombosis and Vascular Biology, studied the effects of moderate amounts of alcohol in human coronary artery smooth muscle cells and in the carotid arteries of mice . In both cases, regular, limited amounts of alcohol inhibited a protein called Notch 1 and prevented the buildup of smooth muscle cells in blood vessels that leads to the narrowing of the arteries and can put you at risk for a heart attack or stroke.
Notch proteins are a family of proteins that span across the membrane of cells. They are important for cell proliferation, differentiation and cell death. When Notch proteins are stimulated by high levels of cholesterol, smoking or changes in blood flow, they cause smooth muscle cells to multiply and can lead to the development of arterial plaques. The accumulation of smooth muscle cells together with immune cells is the central cellular feature of atherosclerosis .
Blood vessel remodeling — when vessels change shape and thickness in response to injury — occurs as the atherosclerotic plaque within the vessel enlarges. Vessel remodeling plays a pathogenic role in chronic inflammatory diseases such as asthma, COPD, rheumatoid arthritis, Crohn’s disease and skin lesions in psoriasis.
In the current study, researchers first confirmed the inhibitory effect of ethanol on a culture of human coronary artery smooth muscle cells. Compared to untreated cell cultures, ethanol treatment inhibited smooth muscle cell proliferation and caused a small increase in the percentage of cells undergoing cell death.
Looking closer, the investigators found that ethanol treatment significantly decreased Notch 1 gene and protein expression, as well as the expression of Notch target genes (i.e. genes that Notch 1 regulates): Hairy/enhancer of split-related with YRPW motif 1 (HEY1) and Hairy/enhancer of split-related with YRPW motif 1 (HEY2). These results were specific to ethanol; methanol and butanol had no significant effect on Notch 1 expression.
Researchers then over-expressed Notch 1 or the target gene HEY1 in cells. Over-expression blocked the inhibitory effect of ethanol. Conversely, when Notch 1 expression was inhibited, smooth muscle cell growth was blocked to a similar extent as treating cells with ethanol.
In a mouse model of vessel remodeling, the remodeling response was inhibited in mice that received moderate levels of alcohol (equivalent in people to 2 drinks per day). Notch expression was inhibited and vessel thickening was reduced.
These findings may one day help scientists create a treatment for heart disease that mimics the beneficial influence of modest alcohol consumption.
David Morrow, Ph.D., an instructor in the Department of Surgery at the Medical Center, first author of the study and an expert on Notch, said :
At the molecular level, this is the first time anyone has linked the benefits of moderate drinking on cardiovascular disease with Notch. Now that we’ve identified Notch as a cell signaling pathway regulated by alcohol, we’re going to delve deeper into the nuts and bolts of the process to try to find out exactly how alcohol inhibits Notch in smooth muscle cells.
While this all sounds good, the latest dietary guidelines make it clear that no one should start drinking or drink more frequently on the basis of potential health benefits. Additionally, the line between moderate alcohol consumption and too much consumption is thin; once you get to 3-4 drinks per day, mortality rates double and the risk of congestive heart failure, pancreatitis, and certain cancers, including breast, liver, and lung, increase. If you do choose to drink, have only a limited amount. A 12-ounce beer, 5-ounce glass of wine or 1.5 ounces of liquor (80 proof) counts as one drink.
- Morrow et al. Alcohol inhibits smooth muscle cell proliferation via regulation of the Notch signaling pathway. Arterioscler Thromb Vasc Biol. 2010 Dec;30(12):2597-603. Epub 2010 Oct 7.
- Raines and Ross. Smooth muscle cells and the pathogenesis of the lesions of atherosclerosis. Br Heart J. 1993 Jan;69(1 Suppl):S30-7.
- Well-Known Molecule May be Behind Alcohol’s Benefits to Heart Health. University of Rochester Medical Center. 2010 Nov 18.