Web edition: November 7, 2012
Print edition: December 15, 2012; Vol.182 #12 (p. 9)
Multivitamins don’t guard against heart attack
A vitamin a day may have its benefits, but protecting against a cardiovascular crisis isn’t one of them. That’s the conclusion of researchers who randomly assigned more than 14,000 men age 50 and older to get a multivitamin or placebo. After 11 years, both groups of men had a similar risk of a heart attack, stroke or of dying of a heart-related event. About one-third of U.S. adults take a multivitamin, said Howard Sesso, an epidemiologist at Harvard Medical School and Brigham and Women’s Hospital in Boston. The study, which Sesso presented November 5, is the first long-term trial to assess whether multivitamins have a cardio-protective role. “The main reason to take multivitamins remains to prevent vitamin and mineral deficiency,” he concluded. The study also appears in the Nov. 7 Journal of the American Medical Association.
Guarding the heart during chemo
Adding two heart-protective drugs to doxorubicin may spare cancer patients the heart damage associated with the chemotherapy drug, researchers at Virginia Commonwealth University in Richmond reported. In lab tests, the scientists found that mouse heart cells exposed to doxorubicin plus the two other drugs, rapamycin and sildenafil, sustained less damage than with doxorubicin alone. Other tests, on human breast cancer cell lines, showed that the added drugs thwarted the activity of certain proteins in cell membranes that expel doxorubicin from cancerous cells before it has a chance to sabotage them. This interference enhanced doxorubicin’s ability to kill cancer cells, says biochemist David Durrant, who presented the findings November 6. Rapamycin is an immune suppressant, while sildenafil is better known as Viagra. “We believe this combination may be an attractive strategy,” said Durrant, who plans to test the drug combo in animals next.
Designer tomatoes fight cholesterol in mice
Scientists have genetically engineered tomatoes that limit artery plaque build-up in mice. The team grew tomatoes that produce a compound called 6F, which works much like a key peptide in “good” cholesterol, or HDL. Then the researchers ground up the tomatoes and fed them to mice as part of a high-fat, high-calorie diet. Other mice just got the diet without the added tomato. All the mice lacked the ability to effectively clear LDL, the bad cholesterol. After 13 weeks, mice getting the unhealthy chow had developed atherosclerotic plaques in the large artery leading out of the heart, said physician Alan Fogelman of UCLA, who presented the data on November 5. But mice getting the genetically engineered tomatoes as 2.2 percent of their chow had half as much plaque in this artery, he said, as well as lower triglyceride levels and less systemic inflammation. Mice that ate tomatoes containing 6F also had lower levels of lysophosphatidic acid, which Fogelman called “a very potent tumor promoter.” Still, Fogelman cautioned, “we are a long way off from testing this in humans.”
Cooler temperatures better for saving heart patients
Dropping a comatose person’s body temperature down to 32° Celsius (89.6° Fahrenheit) after they suffer cardiac arrest outside of a hospital may help limit long-term damage, a small study suggests. Medical guidelines recommend dropping the body temperature down to between 32° and 34° C (93.2° F) for such patients. To test that range, physician Estaban López-de-Sá of La Paz University Hospital in Madrid and colleagues identified 32 comatose patients brought to hospitals after cardiac arrest. They randomly assigned half to be cooled to 32° and half to 34° for 24 hours, followed by a gradual rewarming. The patients kept colder had sharply fewer seizures during the first week. Six months later, eight of 18 patients in the colder group were alive and all of them could function independently. Only two of 18 cooled to 34° were alive at that point. There is evidence that chilling a comatose patient limits damaging chemical reactions in the brain that kick in when blood flow is restored abruptly after cardiac arrest. The study also appeared online November 6 in Circulation.
Multivitamins: H.D. Sesso et al. Multivitamins in the prevention of cardiovascular disease in men. Journal of the American Medical Association, Volume 308, November 5, 2012, p. 1751.
Multivitamins: H.D. Sesso. A randomized trial of a multivitamin in the prevention of cardiovascular disease in men: The Physicians’ Health Study II. Oral presentation session LBCT.03. Late-Breaking Clinical Trials: Treatments for prevention of cardiovascular events. November 5, 2012, American Heart Association Scientific Sessions, Los Angeles.
Doxorubicin: D. Durrant et al. Rapamycin enhances protective effect of sildenafil against doxorubicin cardiotoxicity and potentiates cancer cell killing. Abstract 16494. November 6, 2012, American Heart Association Scientific Sessions, Los Angeles.
Tomatoes: A. M. Fogelman. Genetically engineered tomatoes decrease plaque build-up in mice. Abstract 11083. November 5, 2012, American Heart Association Scientific Sessions, Los Angeles.
Chilling patients: E. Lopez-de-Sa et al. Hypothermia in comatose survivors from out-of-hospital cardiac arrest. Circulation. Online, November 6, 2012. doi: 10.1161/CIRCULATIONAHA.112.136408
Chilling patients: E. Lopez-de-Sa. Pilot trial of two levels of hypothermia in comatose survivors from out-of-hospital cardiac arrest. Oral presentation session LBCT.06. Late-Breaking Clinical Trials: Management of LV dysfunction: Devices and drugs. November 6, 2012, American Heart Association Scientific Sessions, Los Angeles.