Researchers Reduce Enlarged Hearts in Fat Mice

March 7, 2006 08:46:14 PM PST

TUESDAY, March 7 (HealthDay News) -- Using a nerve protection and growth factor called ciliary neurotrophic factor (CNTF) to mimic the activity of the brain hormone leptin, Johns Hopkins researchers were able to dramatically reduce enlarged hearts in obese mice.

Leptin, which is generated by fat cells, signals the brain that it's time to stop eating. An inability to use leptin made naturally in the body is associated with obesity in many people, the researchers noted. Enlarged hearts can lead to heart failure and death.

In this study, the Hopkins team injected CNTF into obese mice that were either deficient or resistant to leptin and had cardiac hypertrophy -- a serious thickening of the heart. After receiving CNTF, the thickened heart walls in the mice were reduced by as much as a third and the overall size of the left ventricle, the main pumping chamber, was reduced by as much as 41 percent, the researchers said.

The study appears in this week's issue of the Proceedings of the National Academy of Sciences.

"These findings suggest that there's a novel brain-signaling pathway in obesity-related heart failure and have therapeutic implications for patients with some forms of obesity-related cardiovascular disease," senior author Dr. Joshua M. Hare, medical director of the heart failure and cardiac transplantation programs at Hopkins, said in a prepared statement.

"We knew that leptin supplements wouldn't address obesity-linked heart disease, but reasoned that CNTF might be a way to get around leptin resistance by activating a related signaling pathway with similar effects on body weight and metabolism," Hare said.

During the next phase of research, he and his colleagues plan to test CNTF in other animal models of hypertrophy not related to obesity.

More information

The American Heart Association has more about enlarged heart.

Weight May Influence Asthma Care

March 7, 2006 08:46:14 PM PST

MONDAY, March 6 (HealthDay News) -- Weight may have a bearing on asthma care: Researchers say beclomethasone, an inhaled steroid, may be better for normal-weight people asthmatics, while an alternate bronchodilator called montelukast sodium (brand name Singulair) may be better for the overweight and obese.

The study, published in the European Respiratory Journal, was funded by Merck & Co., which makes Singulair.

Researchers analyzed data from previous studies that included 3,073 people with moderate asthma. In general, overweight and obese people in these studies had more severe asthma symptoms than other people.

This analysis found that the inhaled steroid was better than Singulair at increasing the number of asthma control days (ACD) among normal-weight people, but the effectiveness of the inhaled steroid decreased with increasing body mass index.

According to the study authors, the positive impact of Singulair did not decrease in overweight and obese people.

"It is increasingly recognized that obese people are more prone to develop asthma, but there is no information about whether obesity influences people's responses to particular asthma medications," study author Dr. Marc Peters-Golden, a professor of internal medicine at the University of Michigan Medical School, said in a prepared statement.

"Our findings are the first to suggest the possibility that obesity might be a factor that influences how well asthmatics respond to particular medications," he said.

More information

The American Academy of Family Physicians has more about asthma treatment.