High blood cholesterol and triglycerides are known risk factors for heart disease. However, it is unclear how much of the risk for either is inherited. To address this question, scientists analyzed DNA from more than 100,000 people in a search for genetic hotspots of heart disease risk. As reported in August 2010, they found nearly 100 hotspots that together account for between a quarter and a third of the inherited portion of blood cholesterol and triglyceride levels.
Ventricular tachycardia (VT) is a potentially life-threatening disorder in which the heart beats too fast and more erratically than normal. VT is typically treated with medicine and/or an implanted pacemaker device — each of which has drawbacks. In November 2010, scientists reported a novel 3-D imaging technique that homes in on specific regions of the heart. Developed and successfully tested in animals, the method could improve VT diagnosis and treatment if it is proven effective in people.
Adults with type 2 diabetes are prone to heart attacks and strokes. Part of the reason is that they often have other cardiovascular risk factors, such as high blood pressure and unhealthy levels of fat in their blood. However, new results showed that lowering blood pressure or cholesterol beyond what is currently recommended did not provide additional benefit for people with diabetes. The March 2010 study will help health care providers and people with diabetes avoid unnecessary treatments.
Each year, about 1 percent of babies are born with abnormally formed hearts. Among the most severe defects is a left pumping chamber too small to work properly. Untreated, the defect is fatal. Three surgeries are needed to repair the defect. In the first, surgeons insert a tiny shunt just after birth to connect the infant’s lungs and heart. In May 2010, researchers published a comparison of two shunts. One was preferable in the short run; long-term follow-up continues.
The development of an embryo into a healthy infant, child, and finally an adult is a truly remarkable process. It occurs through a series of precisely timed molecular events — only some of which scientists know and understand. As reported in February 2010, researchers devised a new computer model that scanned for patterns in the 3 billion-letter human genome. It identified several DNA “switches” that jump-start the development of growing hearts and other organs.
The DASH diet — a low-fat, low-salt diet high in fruits and vegetables — lowered blood pressure in short-term studies of people at risk for stroke and heart disease, but scientists did not know if the approach worked in real-world settings. New research reported in January 2010 confirmed that following the DASH diet and a supervised exercise and weight loss program lowered blood pressure as much as typical reductions from taking high blood pressure medications to reduce disease risk.
Published Study: Effects of the DASH diet alone and in combination with exercise and weight loss on blood pressure and cardiovascular biomarkers in men and women with high blood pressure: the ENCORE study
In a groundbreaking April 2010 pilot study, scientists used a healthy person’s complete genetic sequence to generate a personalized risk report. The researchers first surveyed thousands of publications linking specific DNA sequence variations with a range of diseases and drug responses. Then, using the already-sequenced genome of a 40-year old male volunteer, they calculated the man’s risk of developing 55 conditions, including heart attack and sudden cardiac death, as well as predicted his response to more than 50 medicines.
Understanding and reducing important risk factors, such as smoking, can help prevent heart disease. An April 2010 study showed that CT scans of the heart may be an additional effective screening tool in “intermediate-risk” people — those with a 3 to 10 percent chance of developing heart disease in five years. The scans detect specks of calcium in the walls of coronary arteries. More research is being conducted to weigh the pros and cons of such screening tests.
The heart’s capacity to repair itself after a heart attack is limited. Even when it is able to recover, scar tissue impairs its ability to pump blood. Recent research showed that non-muscle, "fibroblast" cells, which make up more than half the cells in the heart, can be reprogrammed into other cell types — including muscle. In August 2010, scientists identified a trio of gene-controlling proteins that, when "turned on", converted fibroblasts in an injured mouse heart into beating heart muscle cells.
In addition to the human stem cells required in embryos for growth and in adults to maintain tissues such as blood, researchers have devised a third type. Induced pluripotent stem (iPS) cells are made by genetically inducing skin cells to form stem cells than can be turned into any other cell type. Research reported in September 2010 indicates, though, that this "re-programming" process is not perfect: it leaves a small genetic mark on iPS cell’s DNA. The effects remain unknown.
Deterioration of the wall of the thoracic aorta — the major artery in the chest exiting the heart — causes this vessel to weaken, balloon, or split. A rupture of the aorta causes extensive bleeding and is often without warning and fatal. A November 2010 study reported 47 DNA regions unique to people with inherited thoracic aortic disease. This may lead to a genetic test to identify people at risk.
Excess body fat is known to increase type 2 diabetes risk in young and middle-aged adults, but few studies had examined excess body weight and diabetes risk in older adults, even though approximately 70 percent of Americans over 60 are overweight or obese. Collecting data from more than 4,000 research participants, researchers reported in July 2010 that overweight older adults are also at risk for diabetes — pointing to the value of maintaining a healthy weight throughout life.
A pair of 2010 studies showed that an adaptive, "stepped-care" approach using a mix of telephone monitoring, counseling, and medicines relieved depression in people with heart disease and improved their quality of life. Stepped-care therapy individually tailors treatment and adjusts it as needed. In people with one type of heart disease, acute coronary syndrome, the stepped-care therapy not only eased depression but also showed promise in improving heart-related outcomes, a finding that requires confirmation in future studies.
The landmark Women’s Health Initiative investigated the risks and benefits of estrogen plus progestin hormone therapy in postmenopausal women. The study was stopped early, in 2002, when researchers uncovered unexpected health risks for heart attack, stroke, and breast cancer in women taking both hormones. As reported in October 2010, eleven years of follow-up clarified the breast cancer risk, showing that the cancers were more advanced and deadlier in women taking both hormones together.
New results from the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study showed that chronic obstructive pulmonary disease, or COPD, lowers the heart's ability to pump effectively — even in people with few or no symptoms. While scientists have long known about the ultimate impact of severe COPD on the heart, the new findings, reported in January 2010, suggested that heart damage occurs much earlier than previously thought. This underscores the importance of early COPD diagnosis and treatment.
Treatment with low-dose inhaled corticosteroids lets many children with asthma breathe more easily, but it doesn’t work for everyone. A March 2010 study found that children responded quite differently to three supplemental treatments. Most children responded best to adding a long-acting beta-agonist drug, but many children responded best to either adding yet a different drug — a leukotriene modifier — or to increasing the steroid dose. The study points to the value of personalized therapy for individual children with asthma.
Treatment options are limited for adults with asthma that is inadequately controlled with low to moderate doses of inhaled steroid therapy. Researchers reported in September 2010 that supplementing inhaled steroids with a different type of inhaled drug used to treat chronic obstructive pulmonary disease, or COPD, worked better than doubling the steroid dose. It also works just as well as adding a long-acting beta agonist drug. The results suggest new alternatives for the long-term control of adult asthma.
Most extremely preterm newborns have serious trouble breathing, which can be fatal. Standard therapy at birth is surfactant — a liquid that prevents lungs from collapsing when a baby exhales — delivered through a breathing tube, followed by oxygen support. A less invasive approach that doesn’t require a tube uses nasal continuous positive airway pressure (CPAP), to keep the baby’s lungs inflated. Research published in May 2010 showed CPAP at birth to be as good as or better than tube-delivered surfactant in these babies.
Few treatments are available for people with idiopathic pulmonary fibrosis (IPF), a rapidly fatal condition in which the lungs become thick and stiff, making it extremely hard to breathe. An August 2010 study reported the results of testing a blood vessel-opening drug used for pulmonary hypertension on people with IPF. While the drug did not improve exercise capacity — the study’s goal — it did appear to improve the quality of life for some IPF sufferers.
Vitamin A deficiency is common in the developing world. Two 2010 studies, one in mice and one in humans, provided new clues about how vitamin A helps lungs develop and function properly. The mouse study clarified the molecular steps used by vitamin A to help build healthy lungs. The human study discovered that preteens whose chronically malnourished mothers had received vitamin A before, during, and after pregnancy had better lung function than those whose mothers did not get adequate vitamin A.
Recent research points to a potential new strategy for treating pulmonary hypertension, which causes shortness of breath during routine activities, tiredness, chest pain, and a racing heartbeat. Pulmonary hypertension is caused in part by an overgrowth of cells in the small arteries of the lung that makes it harder for the vessels to carry oxygen-rich blood. A June 2010 study identified a gene-controlling mechanism that reversed the growth of lung cells in rats with a condition similar to pulmonary hypertension.
New studies in pigs are helping researchers better understand cystic fibrosis in people. An April 2010 study reported that pigs genetically engineered to develop cystic fibrosis could not rid their airways of bacteria during the first hours after birth, before inflammation occurred. Follow-up work in December 2010 has already enriched this knowledge by identifying the molecular cause of one of the earliest steps in the disease process. These results are helping resolve longstanding questions about the development of cystic fibrosis.
People with end-stage lung disease have few options because of a chronic shortage of lung donors and problems with rejection of donor lungs. New hope comes from a July 2010 study in which scientists rebuilt and transplanted a working rat lung. After first stripping the cells from a rat lung — leaving only its support structure — the researchers repopulated this "scaffold" with cells taken from a newborn rat, and then allowed the cells to grow and develop in another rat.
Although transplants are often successful for certain children with sickle cell disease, these regimens are too toxic for adults who have years of accumulated organ damage from the disease and cannot tolerate complete bone marrow removal. In a medical milestone reported in December 2009, researchers used a specialized, partial blood stem-cell transplant to cure 9 of 10 adults with severe sickle cell disease. Scientists are now perfecting the partial transplant and hope to test it on more people who qualify.
In June 2007, scientists delivered a healthy hemoglobin gene to an adult with severe thalassemia, an inherited blood disorder caused by a defective hemoglobin gene. Three years later, in September 2010, this patient — who had been dependent on monthly blood transfusions since childhood — was still maintaining near-normal hemoglobin levels and had not needed any transfusions. The long-term success of this molecular therapy for thalassemia is a victory both for people with this disease and for molecular medicine.
As reported in March 2010, untreated sleep apnea more than doubles the risk of stroke in middle-aged and older adults — especially men — and independent of other stroke risk factors such as weight, high blood pressure, race, smoking, and diabetes. Pilot studies are now underway to learn how new stroke patients will benefit from sleep apnea treatment, and whether apnea treatment in people at risk helps prevent new cardiovascular disease.
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Last Update: March 2011