Cholesterol-lowering statins show promise against serious infections in sickle cell disease
New research suggests a family of widely used cholesterol-lowering drugs might help protect individuals from serious illness following bacterial infection, including the pneumococcal infections that pose a deadly threat to those with sickle cell disease.
Research led by St. Jude Children’s Research Hospital investigators reported that drugs called statins employ several methods to dampen inflammation and block pneumococcus and certain other bacteria from infecting cells and spreading throughout the body. Elaine Tuomanen, M.D., St. Jude Infectious Diseases chair, said those methods include a newly identified mechanism that statins use to protect healthy cells by blocking the toxicity of an entire class of bacteria. Along with pneumococcus, that class includes diphtheria, tetanus, listeria and group A streptococcus, which is also known as the flesh-eating bacterium.
Tuomanen is co-senior author of the study with Carlos Orihuela, Ph.D., University of Texas Health Science Center at San Antonio (UTHSCSA). The work is published in the January 19 advanced, online edition of The Journal of Clinical Investigation.
The results provide the foundation for a possible future study to determine if statins might protect children with sickle cell disease (SCD) from serious pneumococcal infection. SCD is an inherited blood disorder. The findings also suggest statins might protect others at high risk for pneumonia due to chronic inflammation of the lungs or blood vessels.
Sickle cell is the most common genetic disorder worldwide. In the U.S., the disease most often strikes those of African ancestry. About one in every 375 African Americans newborns inherits the disease.
The risk posed by the pneumococcus is so great that young sickle cell patients are prescribed a daily dose of penicillin in hopes of preventing the infection. Investigators noted that emergence of pneumococcal bacteria resistant to penicillin underscores the need for new prevention tools.
High fructose corn syrup: A recipe for hypertension
A diet high in fructose increases the risk of developing high blood pressure (hypertension), according to research presented recently at the American Society of Nephrology’s 42nd Annual Meeting and Scientific Exposition in San Diego, California. The findings suggest that cutting back on processed foods and beverages that contain high fructose corn syrup may help prevent hypertension.
Over the last 200 years, the rate of fructose intake has directly paralleled the increasing rate of obesity, which has increased sharply in the last 20 years since the introduction of high fructose corn syrup. Today, Americans consume 30 percent more fructose than 20 years ago and up to four times more than 100 years ago, when obesity rates were less than five percent. While this increase mirrors the dramatic rise in the prevalence of hypertension, studies have been inconsistent in linking excess fructose in the diet to hypertension.
Diana Jalal, M.D. (University of Colorado Denver Health Sciences Center), and her colleagues examined 4,528 U.S. adult participants ages 18 or older with no prior history of hypertension. Fructose intake was calculated based on a dietary questionnaire, and foods such as fruit juices, soft drinks, bakery products, and candy were included. Jalal’s team found that people who ate or drank more than 74 grams per day of fructose (2.5 sugary soft drinks per day) increased their risk of developing hypertension. Specifically, a diet of more than 74 grams per day of fructose led to a 28 percent, 36 percent, and 87 percent higher risk for blood pressure levels of 135/85, 140/90, and 160/100 mmHg, respectively. (A normal blood pressure reading is below 120/80 mmHg.)
“These results indicate that high fructose intake in the form of added sugars is significantly and independently associated with higher blood pressure levels in the U.S. adult population with no previous history of hypertension,” the authors concluded. Additional studies are needed to see if low fructose diets can normalize blood pressure and prevent the development of hypertension.
Can charcoal fight heart disease in kidney patients?
Preliminary research indicates that charcoal may provide a new approach to managing the high rate of heart disease in patients with advanced kidney disease.
Patients with advanced kidney disease have high rates of atherosclerosis or “hardening of the arteries,” and death from heart disease. Oral activated charcoal ? a product called AST-120 ? has traditionally been used as an emergency treatment for certain types of poisoning. Recent studies have suggested that AST-120 may exert beneficial effects in kidney disease.
“We found that oral activated charcoal lessens atherosclerotic lesions in experimental mice with kidney damage,” said Valentina Kon, M.D. of Vanderbilt University. “This is especially important because there is no effective treatment to reduce the high rate of cardiovascular mortality in patients with end-stage renal disease.”
The researchers studied the effects of AST-120 in mice genetically engineered to develop atherosclerosis. The effects were assessed in mice with different levels of kidney mass.
In mice with profoundly reduced renal mass, treatment with AST-120 led to a dramatic decrease in atherosclerosis. This was so even when charcoal treatment was delayed. The improvement in atherosclerosis was unrelated to changes in blood pressure or cholesterol levels. Rather, the effect appeared related to reduced inflammation in the blood vessels.
In mice, oral activated charcoal appears to reduce atherosclerosis associated with kidney disease. The effect is present at different levels of kidney function, in very advanced atherosclerosis, and even when treatment is delayed.
The preliminary research was presented at the American Society of Nephrology’s 42nd Annual Meeting and Scientific Exposition in San Diego, Calif.
More research is needed to see if AST-120 offers similar benefits in humans with kidney disease.
The research was supported by Kureha Chemical Industry Co., Ltd., Tokyo, which makes AST-120.
One form of natural vitamin E protects brain after stroke
Blocking the function of an enzyme in the brain with a specific kind of vitamin E can prevent nerve cells from dying after a stroke, new research suggests.
In a study using mouse brain cells, scientists found that the tocotrienol form of vitamin E, an alternative to the popular drugstore supplement, stopped the enzyme from releasing fatty acids that eventually kill neurons.
Ohio State University researchers have been studying how this form of vitamin E protects the brain in animal and cell models for a decade, and intend to pursue tests of its potential to both prevent and treat strokes in humans.
“Our research suggests that the different forms of natural vitamin E have distinct functions. The relatively poorly studied tocotrienol form of natural vitamin E targets specific pathways to protect against neural cell death and rescues the brain after stroke injury,” said Chandan Sen, professor and vice chair for research in Ohio State’s Department of Surgery and senior author of the study.
“Here, we identify a novel target for tocotrienol that explains how neural cells are protected.”
The research appears online in the Journal of Neurochemistry.
Vitamin E occurs naturally in eight different forms. The best-known form of vitamin E belongs to a variety called tocopherols. This form of vitamin E (tocotrienol or TCT) is not abundant in the American diet but is available as a nutritional supplement. It is a common component of a typical Southeast Asian diet.
“We have studied an enzyme that is present all the time, but one that is activated after a stroke in a way that causes neurodegeneration. We found that it can be put in check by very low levels of tocotrienol,” Sen said. “So what we have here is a naturally derived nutrient, rather than a drug, that provides this beneficial impact.”
One in five American youths have abnormal lipid levels
Twenty percent of young people aged 12-19 years in the United States have at least one abnormal lipid level, according to a study from the Centers for Disease Control and Prevention. Abnormal lipid levels are major risk factors for heart disease, the leading cause of death among adults in the United States.
The report, “Prevalence of Abnormal Lipid Levels among Youths -United States, 1999-2006,” was published recently in CDC’s Morbidity and Mortality Weekly Report (MMWR).
The report examined data for 1999-2006 from the National Health and Nutrition Examination Survey (NHANES), an ongoing study that explores the health and nutritional status of about 6,000 participants every year. Researchers analyzed measurements of low-density lipoprotein, or “bad,” cholesterol (LDL-C); high-density lipoprotein, or “good” cholesterol (HDL-C); and triglycerides.
The researchers found that young people who were overweight or obese were more likely to have one or more abnormal lipid levels compared to normal weight youth. Fourteen percent of normal weight, 22 percent of overweight, and 43 percent of obese youth had one or more abnormal lipid levels.
The study also found that 32 percent of these young people would be candidates for lipid screening based on American Academy of Pediatrics (AAP) guidelines. The AAP recommends lipid screening for young people with a family history of high blood cholesterol or premature cardiovascular disease, or the presence of at least one major risk factor for heart disease, such as smoking, high blood pressure, diabetes, or overweight/obesity.
Reviewing health indicators for 3,125 youths, researchers found that differences in lipid levels were associated with sex, age, and race/ethnicity. Specifically:
• More boys (24 percent) than girls (16 percent) had at least one abnormal lipid level.
• Fourteen- and 15-year-olds (9 percent) and 18- and 19-year-olds (10
percent) were more likely to have low HDL (good) cholesterol levels than 12- and 13-year-olds (5 percent).
• Non-Hispanic white youths were more likely to have low levels of HDL (good) cholesterol (8 percent) and high triglycerides (12 percent), compared to non-Hispanic black youths (5 percent and 4 percent, respectively).
Typically, heart disease develops in adulthood. But its risk factors, such as abnormal lipid levels and overweight/obesity often emerge during childhood and adolescence.
In the past three decades, obesity among American youths has increased from 5 percent to more than 17 percent. In light of this, the study’s authors suggested that clinicians should be aware of guidelines for lipid screening and treatment among youths.