Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Low blood oxygen may lead to heart defects in children with sickle cell disease

28.04.2010
Children with sickle cell disease who also have lower blood oxygen levels while both asleep and awake are likely to have heart abnormalities, researchers at Washington University School of Medicine in St. Louis and other institutions have found.

Heart problems are fairly common in young adults with sickle cell disease, but physicians don't fully understand why. The researchers demonstrated that lower oxygen saturation in the blood was linked to the heart structure seen in the 44 children studied.

Sickle cell disease is an inherited blood disorder affecting red blood cells, which contain hemoglobin, the substance that carries oxygen from the lungs to all parts of the body. In patients with this disease, red blood cells contain an abnormal type of hemoglobin that causes the normally round, flexible red blood cells to become stiff and sickle- or crescent-shaped. The sickle cells can't pass through tiny blood vessels, which can prevent blood from reaching some tissues and can result in tissue and organ damage, pain and stroke.

In addition, sickle cells are short lived and lead to a shortage of red blood cells and anemia, which make the heart grow bigger because it has to work harder, says Mark C. Johnson, MD, associate professor of pediatrics at Washington University School of Medicine and first author of the study.

In this study, the first to analyze sleep studies and echocardiograms of children with sickle cell disease, these heart abnormalities were found in the left pumping chamber, or left ventricle, of the children's hearts. The findings included an enlarged left ventricle, called ventricular hypertrophy, and abnormal blood filling of the left ventricle, called diastolic dysfunction. Both are associated with early death in adults with sickle cell disease, but the meanings of the same results in children are unclear.

"This suggests that the beginning of adult heart disease may start in children, but we need to follow these patients longitudinally to strengthen the meaning of the findings," says Michael R. DeBaun, MD, a Washington University sickle cell disease specialist at St. Louis Children's Hospital and senior author of the study, published online in Blood First Edition April 8, 2010.

"Many researchers assumed it was the anemia alone that makes the heart enlarge, but this study suggests it's not that simple," Johnson says.

Researchers began the study thinking that the abnormalities in the left ventricle, the heart's main blood-pumping chamber, would be the result of sleep-disordered breathing, such as sleep apnea, commonly found in children with sickle cell disease. Sleep-disordered breathing has previously been associated with left ventricle hypertrophy and with diastolic dysfunction in children and adults. But only about one-fifth of the children had some evidence of obstructive apnea hypopnea, or recurrent episodes of upper airway collapse and obstruction during sleep.

Researchers also thought they would find lower oxygen saturation while patients were sleeping compared to when they were awake. However, the average oxygen saturation while asleep and awake were similar. Only about one-fourth of patients had average oxygen saturation values below normal.

The echocardiograms showed that 46 percent of participants had left ventricle hypertrophy in which the chamber of the left ventricle was enlarged. The research team's analysis showed that for every 1 percent drop in oxygen saturation, there was a measurable increase in the mass of the heart's left ventricle.

"The average oxygen saturation of 97 percent in these children is in a normal range, but the patients with slightly lower levels had enlarged hearts," Johnson says. "A relatively small change in oxygen levels caused a big change in the heart. That's what makes us think there's something under the surface that we don't quite understand yet."

The team also measured an indicator of pulmonary hypertension, or high blood pressure in the lungs, the major cause of death in adults with sickle cell disease. When the pulmonary hypertension level is raised in adults with sickle cell disease, it is a strong predictor of death within 24 months. However, despite the strong association between pulmonary hypertension and sleep abnormalities, no such association was demonstrated in this study, DeBaun says.

Johnson and DeBaun say more sleep and cardiac studies are needed to confirm the association of left ventricle abnormalities with low blood oxygen levels. In the future, the researchers plan to look at other indicators to find potential new therapies to prevent progression of the disease.

Johnson M, Kirkham F, Redline S, Rosen C, Yan Y, Roberts I, Gruenwald J, Marek J, DeBaun M. Left Ventricular Hypertrophy and Diastolic Dysfunction in Children with Sickle Cell Disease are Related to Asleep and Waking Oxygen Desaturation. Blood First Edition. Prepublished online April 8, 2010.

Funding for this study was provided by the National Heart, Lung, and Blood Institute.

Washington University School of Medicine's 2,100 employed and volunteer faculty physicians also are the medical staff of Barnes-Jewish and St. Louis Children's hospitals. The School of Medicine is one of the leading medical research, teaching and patient care institutions in the nation, currently ranked fourth in the nation by U.S. News & World Report. Through its affiliations with Barnes-Jewish and St. Louis Children's hospitals, the School of Medicine is linked to BJC HealthCare.

Beth Miller | EurekAlert!
Further information:
http://www.wustl.edu

More articles from Health and Medicine:

nachricht GLUT5 fluorescent probe fingerprints cancer cells
20.04.2018 | Michigan Technological University

nachricht Scientists re-create brain neurons to study obesity and personalize treatment
20.04.2018 | Cedars-Sinai Medical Center

All articles from Health and Medicine >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Spider silk key to new bone-fixing composite

University of Connecticut researchers have created a biodegradable composite made of silk fibers that can be used to repair broken load-bearing bones without the complications sometimes presented by other materials.

Repairing major load-bearing bones such as those in the leg can be a long and uncomfortable process.

Im Focus: Writing and deleting magnets with lasers

Study published in the journal ACS Applied Materials & Interfaces is the outcome of an international effort that included teams from Dresden and Berlin in Germany, and the US.

Scientists at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) together with colleagues from the Helmholtz-Zentrum Berlin (HZB) and the University of Virginia...

Im Focus: Gamma-ray flashes from plasma filaments

Novel highly efficient and brilliant gamma-ray source: Based on model calculations, physicists of the Max PIanck Institute for Nuclear Physics in Heidelberg propose a novel method for an efficient high-brilliance gamma-ray source. A giant collimated gamma-ray pulse is generated from the interaction of a dense ultra-relativistic electron beam with a thin solid conductor. Energetic gamma-rays are copiously produced as the electron beam splits into filaments while propagating across the conductor. The resulting gamma-ray energy and flux enable novel experiments in nuclear and fundamental physics.

The typical wavelength of light interacting with an object of the microcosm scales with the size of this object. For atoms, this ranges from visible light to...

Im Focus: Basel researchers succeed in cultivating cartilage from stem cells

Stable joint cartilage can be produced from adult stem cells originating from bone marrow. This is made possible by inducing specific molecular processes occurring during embryonic cartilage formation, as researchers from the University and University Hospital of Basel report in the scientific journal PNAS.

Certain mesenchymal stem/stromal cells from the bone marrow of adults are considered extremely promising for skeletal tissue regeneration. These adult stem...

Im Focus: Like a wedge in a hinge

Researchers lay groundwork to tailor drugs for new targets in cancer therapy

In the fight against cancer, scientists are developing new drugs to hit tumor cells at so far unused weak points. Such a “sore spot” is the protein complex...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

IWOLIA: A conference bringing together German Industrie 4.0 and French Industrie du Futur

09.04.2018 | Event News

 
Latest News

Magnetic nano-imaging on a table top

20.04.2018 | Physics and Astronomy

Start of work for the world's largest electric truck

20.04.2018 | Interdisciplinary Research

Atoms may hum a tune from grand cosmic symphony

20.04.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>