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In the News |
NHLBI Trial Shows Surgery Offers High Risk, Little Benefit, for Some Emphysema Sufferers Hypertension Diet also Lowers Cholesterol Recent Advances from the NHLBI |
On July 25, Congressman Clifford Stearns (R-FL) introduced a resolution (H. Con. Res. 197) to establish Chronic Obstructive Pulmonary Disease (COPD) Awareness Month. The goal would be to raise public awareness about the prevalence of the disease and the serious problems associated with it. COPD is a slowly progressive disease of the airways characterized by gradual loss of lung function. In the United States, the term COPD includes chronic bronchitis, chronic obstructive bronchitis, or emphysema, or a combination of these conditions. Approximately 16 million Americans have COPD. In 2000, COPD ranked as the fourth leading cause of death both in the United States and worldwide.
As of July 30, the House and Senate Appropriations Committees were in the process of finalizing their recommendations for the Fiscal Year 2002 budget. Once the committees have completed their work, the bills will go to their respective chambers for debate and approval. After a conference committee resolves any differences between the bills, the House and the Senate must approve the conference committee's version before it can be sent to the President to be signed into law.
Early results from the NHLBI-supported National Emphysema Treatment Trial (NETT) show that emphysema patients who have severe lung obstruction with either limited ability to exchange gas when breathing or damage that is evenly distributed throughout their lungs receive little benefit from lung volume reduction surgery (LVRS) and are at high risk of death from the procedure. This is the first time that researchers have identified scientifically based selection criteria for patients seeking LVRS as a treatment for advanced emphysema. When discussing the result, Dr. Lenfant stated "Identifying which patients should not undergo this surgery is a key goal of this study. We expect the final results of NETT will guide us further in determining if and when this procedure should be used to treat emphysema."
People who are following the DASH (Dietary Approaches to Stop Hypertension) diet to lower their blood pressure will be pleased to know that they are lowering their risk of heart disease and stroke in more ways than one. In addition to lowering blood pressure in hypertensive patients and reducing elevated levels of the amino acid homocysteine (a risk factor for heart disease, stroke, and peripheral vascular disease), the DASH diet significantly reduces a person's levels of total cholesterol and of low density lipoprotein (LDL) or "bad" cholesterol. This effect was seen in both black and white study participants.
The diet, which is low in saturated fat and cholesterol and promotes the use of low fat dairy foods, is much higher in fruits and vegetables than a typical cholesterol-lowering diet. However, it is consistent with the NCEP's new guidelines, and adds one more tool to the armament of interventions known to help lower a person's risk for CHD.
Investigators studying nearly 700 adults found that weight gains of 5 to 20 percent increase the risk of developing sleep apnea by 2.5 to 37 times, respectively. More important, weight loss was associated with reduced sleep apnea severity and decreased likelihood of developing moderate to severe sleep apnea. Sleep apnea, a prevalent and potentially serious medical condition, is characterized by repeated episodes of airway obstruction during sleep and excessive daytime sleepiness. These results strongly suggest that weight loss and prevention of weight gain, through diet or exercise, offer an effective approach for its prevention and treatment.
A pneumonia-like illness known as acute chest syndrome (ACS) is the leading cause of morbidity and early death in patients with sickle cell disease. Researchers have shown that elevated levels of an enzyme called secretory phospholipase A2 are associated with the development of acute chest syndrome. If confirmed by larger clinical studies, enzyme measurements could be used to identify patients with impending ACS, thereby allowing them to receive therapies that will reduce the severity of ACS or prevent its development.
Challenging one of medicine's long-standing beliefs, a team of scientists funded by the NHLBI and the National Institute on Aging has found the strongest evidence to date that human heart muscle cells regenerate after a heart attack. The scientists found muscle cells dividing in two regions of the heart, and identified several other key indicators of cell regeneration. "It has long been assumed that when the heart is damaged - such as after a heart attack - heart muscle cells do not regenerate and the damage is permanent. Now, this latest research provides the most dramatic and clear-cut demonstration to date of heart cell regeneration after cardiac injury," said Dr. Lenfant. "With this landmark study, we have a new understanding of the heart that opens up the possibility of repairing heart muscle damage after a heart attack."
According to the study's principal investigator, Dr. Piero Anversa, the next challenge is to find the source of the dividing cells and establish if they truly are cardiac stem cells. "If we can prove the existence of cardiac stem cells and make these cells migrate to the region of tissue damage, we could conceivably improve the repair of damaged heart muscle and reduce heart failure," said Anversa. Research on animal models supports this possibility. Anversa also has published research showing that adult stem cells isolated from mouse bone and injected into a damaged mouse heart became functioning heart muscle by developing into myocytes and coronary vessels. Moreover, the new tissue partially restored the heart's ability to pump blood.
Researchers recently discovered that perilipin, a protein associated with fat metabolism and weight gain in mice and humans, acts by preventing a "fat-burning" enzyme from entering fat cells where it can break down fat molecules and convert them to energy. They also showed that mice genetically modified to lack perilipin had about half as much body fat, 8 percent more muscle, and higher metabolic rates than did normal mice, despite eating 25 percent more food. Moreover, a mutation for perilipin deficiency prevented obesity in mice that had been genetically programmed to be obese. Since perilipin has been found only on fat cells, researchers hope new anti-obesity drugs can be developed that will reduce perilipin activity and will work exclusively on adipose tissues without side effects on other tissues.
A heart attack involves injury to heart muscle that occurs when arteries supplying blood to the heart become blocked. Sometimes patients improve if the blood flow can be restored via a revascularization procedure such as angioplasty or bypass surgery. However, the procedures are not risk-free; patients have a 2 to 5 percent chance of experiencing serious complications, including death. Therefore, it is critical that patients do not undergo the revascularization procedures needlessly, but it is equally important to treat those for whom the benefits outweigh the risks.
One such patient would be someone experiencing cardiogenic shock, the leading cause of death for patients hospitalized due to heart attacks. As demonstrated by the NHLBI's SHOCK Trial, heart attack patients who received revascularization immediately after developing cardiogenic shock were significantly more likely to be alive one year after their heart attacks than were those who developed cardiogenic shock but did not receive the procedure. Therefore, the American College of Cardiology and the American Heart Association recommend revascularization for patients younger than 75 years who develop cardiogenic shock within 36 hours of a heart attack.
Due to recent advances in magnetic resonance imaging (MRI) technologies, physicians may soon be able to identify other people for whom the risks of these invasive procedures outweigh the benefits. For example, a new MRI technique using contrast agents helps distinguish between patients with irreversibly damaged left ventricles and those in whom damage can be reversed by revascularization. Moreover, the technique is powerful enough to identify damaged tissue even in patients who are not aware that they had ever experienced a heart attack.
Researchers recently completed two studies addressing whether long-acting beta-agonists (LABs) should replace or supplement inhaled corticosteroids (ICS) as treatment for adults with mild-to-moderate persistent asthma. The results, published in the May 23, 2001 issue of the Journal of the American Medical Association, showed that LABs alone are not as effective as ICS alone in treating adults with mild-to-moderate persistent asthma. However, many patients with asthma were treated successfully with lower doses of steroids if they also took LABs. In a statement announcing the results Dr. Lenfant said "These two studies provide new and important scientific information about treatment questions that clinicians face every day in managing adult patients with mild-to-moderate persistent asthma: can they switch patients to long-acting beta-agonists from inhaled corticosteroids or use long-acting beta-agonists to reduce steroid doses? Now we have the answer."