Growth Hormone Therapy Improves the Growth of Children’s Hearts
For the first time, a long-term study in children has shown that a medication can improve the growth of the hearts of children that are too small for the size of their bodies. The research has implications for the thousands of childhood cancer survivors who often undergo treatment that can drastically reduce the size of their hearts and for other children with inadequate heart size.
Children treated with anthracycline chemotherapeutic drugs for leukemia often suffer from reduced and insufficient amount of heart muscle as they get older and this is related to their anthracycline treatment. The inadequate amount of heart muscle in anthracycline-treated long-term survivors of childhood cancer can result in heart failure and the need for heart transplant or cardiac-related death years later. A new study just published in the leading child health journal Pediatrics finds that growth hormone therapy given to these children has a beneficial impact on their cardiac health by improving the growth of these children’s hearts.
The researchers examined cardiac findings for 34 childhood cancer survivors treated with anthracyclines, a family of chemotherapy drugs that include Adriamycin,™ with several years of growth hormone therapy and baseline cardiac scores similar to a comparison group of survivors who did not receive growth hormone therapy, and a control group of a healthy pediatric population.
“We undertook this study in an effort to determine if the long-term effects of growth hormone therapy among anthracycline-treated children with left ventricular dysfunction result in improvement in the cardiac abnormalities that this high risk population for premature heart disease is known to have,” said Steven Lipshultz, M.D., professor and chairman of the Department of Pediatrics at the University of Miami Leonard M. Miller School of Medicine. “We performed a 10-year longitudinal study of cardiac structure and function before, during and after growth hormone therapy, and we found the negative growth effects to the heart went away when growth hormone therapy was instituted. Growth hormone did make the left ventricular wall thickness and mass more normal while children were receiving growth hormone.”
This study suggests that these long-term survivors of childhood cancer have growth hormone deficiency and that physiologic replacement therapy is important to reduce cardiovascular risk. This study clearly shows that the cardiovascular effects of growth hormone replacement therapy leads to more normalization of left ventricular wall thickness (the main pumping chamber of the heart) and its’ mass, as well as for the heart rate and blood pressure.
This study raises the question of whether to formally assess for growth hormone deficiency early on in survivors of childhood cancer to initiate lifelong replacement therapy, if needed, early to reduce global cardiovascular risk.. Non-oncology patients with growth hormone deficiency will eventually develop left ventricular dysfunction due to growth hormone deficiency. These patients will also develop dyslipidemia, insulin resistance, decreased skeletal muscle mass, decreased exercise tolerance, decreased strength, and increased body fat. All of these are associated with higher risks of premature symptomatic cardiovascular diseases including congestive heart failure from left ventricular dysfunction and accelerated atherosclerosis and myocardial infarction from dyslipidemia and metabolic complications. So, from a cardiovascular perspective early identification of growth hormone deficiency and its treatment at physiologic replacement levels, would be encouraged.
Media Contact: Omar Montejo
June 24, 2005