Newly identified grape flavonoids can inhibit cancer growth
Researchers at the University of Illinois at Urbana-Champaign discovered that certain phytochemicals from the proanthocyanidin and anthocyanin classes of flavonoids found in grapes are effective at inhibiting an enzyme used by cancer cells to proliferate. Flavonoids include a number of water-soluble compounds responsible for the color in plants, whose health benefits are being increasingly revealed. The research was reported online on March 1 2005 in The Journal of Agricultural and Food Chemistry (http://pubs.acs.org/journals/jafcau/).
University of Illinois professor in the department of natural resources and environmental sciences Mary Ann Lila, and colleagues analyzed the ability of grape cell cultures to inhibit human DNA topoisomerase II, an enzyme necessary for the growth of cancer. The researchers identified cyanidin-3,5-diglucoside, malvidin-3-acetylglucoside, peonidin-3-coumaryl-5-diglucoside, procyanidin B1, procyanidin B2, procyanidin B5, procyanidin dimer digallate, procyanidin C1, myricetin, and rutin, as having a synergistic benefit greater than resveratrol or quercetin, which have also shown anticancer effects. The compounds had less of an inhibitory effect on topoisomerase II when studied by themselves. Dr Lila commented, "We definitely had very potent activity against the particular antibody system we were using, which was that of the critical proliferation stage of carcinogenesis. In our subsequent studies now under way in animal models, we are getting direct evidence that these components in grapes work synergistically in fighting cancer. They have to work together to obtain the potency that works."
Elvira Gonzalez de Mejia, a professor in the department of food science and human nutrition who also worked on the project added,"Some of the compounds we identified have not been reported in cell culture and grapes. Some have high inhibitory activity in the promotion and progression stages of cancer and have a high probability to work against the disease."
Endothelial cells make C-reactive protein
In an article scheduled to appear in the April 2005 issue of American Journal of Pathology (http://ajp.amjpathol.org/) researchers from the University of California Davis School of Medicine report that cells lining the arteries known as endothelial cells produce C-reactive protein, or CRP. CRP is a marker of inflammation that, when elevated in the blood, indicates increased heart disease risk, and is known to be made by the liver. The endothelial cells which line the arteries have been believed to offer protection against CRP. C-reactive protein induces endothelial cell dysfunction and plaque formation by causing the cells to produce less nitric oxide and by increasing cell adhesion molecules, allowing white blood cells to enter and damage the blood vessels.
Coauthor and professor of pathology and internal medicine at UC Davis Medical Center, Ishwarlal Jialal, explained their discovery: "This is an extremely important finding. We have convincingly demonstrated in this paper that aortic and coronary artery endothelial cells produce and secrete C-reactive protein. We also showed within the artery, mature white cells, called macrophages, make chemical messengers, cytokines, which enhance the C-reactive protein secretion by endothelial cells at least ten-fold."
He added, "This tells us that there is cross-talk in the active plaque where these cells act in concert to cause very high C-reactive protein levels in the atheroma, which is the accumulation of plaque on the innermost layer of the artery. The C-reactive protein produced by endothelial cells can not only act on the endothelial cells, but also on macrophages and smooth muscle cells in the atheroma. This creates a vicious cycle, leading to plaque instability and rupture, and ultimately heart attacks and strokes."
The authors also found that C-reactive protein causes endothelial cells to produce plasminogen activator inhibitor, which can lead to blood clot formation. Other research has indicated that plaque itself also makes CRP.
Aspirin may be useful to help prevent pre-eclampsia
Researchers led by Colin D. Funk of Queen’s University in Ontario, Canada have determined that low dose aspirin could be used to prevent and treat pre-eclampsia, a disorder that effects 5 to 10 percent of all pregnancies that can threaten both the mother and child. The disease is characterized by high blood pressure in the mother, and is believed to be linked with long-term heart disease in both the mother and child. The study was published online on March 17, 2005 in the Journal of Clinical Investigation.
Calcium supplements help build strong bones in teenaged boys
A study published on March 8 2005 online in Journal of Clinical Endocrinology & Metabolism found that boys who received calcium supplements had greater bone mineral content and were taller than those who did not receive the supplements. Improving bone mineral content early in life is believed to help reduce osteoporotic fractures later on.
Researchers at the Medical Research Council Human Nutrition Research, Elsie Widdowsom Laboratory in Cambridge, England, randomized 143 boys ages 16 to 18 to receive 500 milligrams calcium twice per day in the form of calcium carbonate, or a placebo for 13 months. Additionally, participants were grouped according to whether their activity level was high or low. Bone mineral content, bone area, lean and fat mass, height, and weight were measured before, during and following the treatment period.
Although both groups experienced increases in height, weight, lean and fat mass and most bone measurements over the course of the study, the group receiving calcium was found to have a significant increase in height, lean mass and bone mineral content of the whole body, lumbar spine and and hip compared to the boys who received a placebo. Adjustment for bone area and height lessened the increase in bone mineral content, which suggested that calcium's effect was accomplished through an effect on growth. Physical activity level appeared to increase the effect of calcium supplementation on bone mineral content only in an area of the upper leg bone.
The authors conclude that "calcium carbonate supplementation of adolescent boys increased skeletal growth, resulting in greater stature and bone mineral acquisition. Follow-up studies will determine whether this reflects a change in the tempo of growth or an effect on skeletal size that persists into adulthood."
Five percent reduction in calories provides significant reduction in cancer risk
A study scheduled to be published in the May 2005 issue of the American Journal of Physiology-Endocrinology and Metabolism (http://ajpendo.physiology.org/) found that reducing the calories of mice by only 5 percent was almost as effective as reducing calories by a third in preventing cell proliferation, an indicator of cancer risk. Reducing the calories of laboratory animals by amounts as great as 50 percent in some studies has been found to reduce the risk of cell proliferation and cancer, as well as lengthen maximum lifespan.
Researchers at the University of California, Berkeley fed mice three days per week, which provided them with 5 percent fewer calories than those consumed by mice allowed to eat as much as they desired. Other mice were fed diets containing 33 percent fewer calories than those consumed by the free fed mice.
The researchers found that the three day per week regimen was nearly as effective as the more stringent 33 percent calorie restriction in reducing cell proliferation in breast, skin and T cells, compared to the free fed mice. Lead investigator and professor of nutrition Marc Hellerstein, of the Department of Nutritional Sciences and Toxicology at UC Berkeley's College of Natural Resources explained, "Cell proliferation is really the key to the modern epidemic of cancer. Normally, a cell will try to fix any damage that has occurred to its DNA. But, if it divides before it has a chance to fix the damage, then that damage becomes memorialized as a mutation in the offspring cells. Slowing down the rate of cell proliferation essentially buys time for the cells to repair genetic damage."
Lead author Elaine Hsieh observed, "Cutting just a few calories overall but feeding intermittently may be a more feasible eating pattern for some people to maintain."
AMA journal says vitamin E preventive benefit in macular degeneration outweighs possible risks
Blood marker predicts heart disease mortality
Blood levels of a peptide hormone can help predict mortality risk in patients with known but stable coronary artery disease, as reported by Danish researchers.*
Following its release, the hormone is split into two byproducts: brain natriuretic peptide (BNP) and its fragment, NT-pro-BNP. BNP is useful in rapid, accurate diagnosis of heart failure, while both BNP and NT-pro-BNP can reliably predict mortality in patients with acute coronary syndromes. NT-pro-BNP levels are known to rise after a heart attack.
The Danish study followed 1,034 patients with signs or symptoms of coronary artery disease who were referred for angiography. Blood NT-pro-BNP levels were elevated in all subjects compared to those without coronary artery disease. After nine years of follow-up, subjects with the highest NT-pro-BNP levels had a significantly higher rate of mortality than those with the lowest levels. Higher levels of NT-pro-BNP were correlated with more serious coronary artery disease, lower left ventricular ejection fraction, and a decreased marker of kidney function.
After adjusting for other risk factors, NT-pro-BNP level was found to be an independent predictor of survival in patients with stable coronary artery disease. Because NT-pro-BNP is elevated by each ischemic event, its correlation with greater mortality may reflect the frequency of such coronary events.
For the first time, patients with known coronary artery disease can be monitored using simple laboratory testing rather than invasive procedures. These findings also suggest that NT-pro-BNP may be suitable as a screening tool for undiagnosed coronary artery disease.
—Linda M. Smith, RN
*Kragelund C, Gronning B, Kober L, Hildebrandt P, Steffensen R. N-terminal pro-B-type natriuretic peptide and longterm mortality in stable coronary heart disease. N Engl J Med. 2005 Feb 17;352(7):666-75.
Aspirin lowers women's stroke risk
The authors of the report state that the Women's Health Study's results are particularly relevant since women have a relatively greater proportion of strokes than of heart attacks compared to men. They note that they cannot rule out the possibility that the lack of a significant reduction in heart attack in this study could be due to an insufficient dose of aspirin, or to taking the drug on alternate days.
Inflammation in rheumatoid arthritis linked to cardiovascular disease mortality
The March 2005 issue of Arthritis & Rheumatism (http://www.rheumatology.org/publications/ar) published the findings of Mayo Clinic epidemiologists that the body-wide inflammation of rheumatoid arthritis may be to blame for the increased risk of cardiovascular death in patients with the disease. Individuals with the disease have been shown to have a greater risk of dying of cardiovascular disease if they have large joint swelling, inflammation of the blood vessels (vasculitis), rheumatoid lung disease or a high erythrocyte sedimentation rate (ESR), which measures inflammation in the body.
Hilal Maradit Kremers, MD, and colleagues followed 603 Rochester, Minnesota residents diagnosed with rheumatoid arthritis between 1955 and 1995. Information on cardiac events, cardiovascular risk factors, indicators of systemic inflammation, and information concerning rheumatoid arthritis severity was collected, as well as data on the presence of additional diseases. The subjects were followed until death or January of 2001.
Three hundred fifty-four patients died during follow up, for which cardiovascular disease was the cause of death for 176. The risk of dying from cardiovascular disease was significantly higher among subjects who had experienced at least three elevations of ESR values, inflammation of the blood vessels, and rheumatoid lung disease, with the presence of any of these factors more than doubling cardiovascular mortality risk.
Although the precise mechanism by which the inflammation of rheumatoid arthritis causes heart disease is not known, the researchers believe that if the process is kept under control, cardiovascular mortality could be lowered.
Senior author and Mayo Clinic rheumatologist and epidemiologist, Sherine Gabriel, MD, commented, "Our previous research showed that rheumatoid arthritis patients have a higher risk of early death than others and that these deaths are mostly due to cardiovascular disease. We suspect that systemic inflammation promotes this risk. Our findings support this hypothesis."
Higher vitamin E levels mean lower prostate cancer risk
Folic acid and B12 reduce post-stroke fracture risk
At the study's conclusion, 27 hip fractures had occurred in the placebo group, compared to 6 that had occurred amongst those who received folic acid and vitamin B12. When total fractures were compared, 32 placebo patients and 8 who had received the vitamins experienced fractures of any type. Homocysteine levels increased by 31 percent in the group who received the placebo, while declining by 38 percent in the vitamin-treated group.
In an accompanying editorial, Joyce B.J. van Meurs, PhD, and André G. Uitterlinden, PhD, from the Erasmus Medical Center, in Rotterdam, the Netherlands, write, "After the initial observation of association between circulating homocysteine levels and fracture risk less than one year ago, these results now support a causal link."
Prostate drug could save lives