School of Medicine physicians have noted that children treated for sickle cell disease have worse symptoms if they are also asthma sufferers. Further, children with asthma often also have breathing disturbances during sleep.
These observations led to an all-out effort to find better treatments for these children and to thoroughly investigate the link between asthma and breathing problems during sleep and the severity of sickle cell disease complications.
About four years ago, Michael R. DeBaun, M.D., associate professor of pediatrics, and Robert C. Strunk, M.D., the Donald Strominger Professor of Pediatrics, independently found that children with both sickle cell disease and asthma had more hospital admissions and lung complications than children with sickle cell disease alone.
So they established a combined pulmonary/sickle cell disease clinic at St. Louis Children’s Hospital, bringing together pediatric lung and blood specialists to evaluate children with sickle cell disease.
This novel team approach has now led to a four-year, $8 million grant from the National Heart, Lung, and Blood Institute to investigate asthma and nocturnal hypoxia (low oxygen levels during sleep) in sickle cell disease.
The prevalence of asthma in the African-American urban population in the St. Louis area is about 17 percent, and the researchers’ data indicate that the same asthma prevalence holds for children with sickle cell disease.
Originating from a variety of causes, low oxygen levels in the blood of sickle cell patients can initiate episodes of debilitating pain in the arms, legs, back, abdomen, bones or joints. These episodes can also involve the lungs if they progress to acute chest syndrome — a pneumonia-like condition accompanied by fever, pain and violent coughing. Acute chest syndrome is the leading cause of death and the second-most-common cause of hospitalization in patients with sickle cell disease.
Sickle cell disease is the most common disorder identified as part of the state mandated newborn screening, occurring in one of 1,800 newborns in America and one of 400 newborns of African-American descent.
The disease stems from variations in the gene for hemoglobin, the oxygen-carrying component of red blood cells. At low oxygen levels, variant hemoglobin clumps together and warps red cells into hard sickle shapes so that they tend to clog up small blood vessels.
This study will follow at least 400 children with sickle cell disease and specifically address the relation of lung problems to the severity of sickle cell symptoms and the effects of sickle cell disease on the lungs. Physicians will look at the children’s genetic makeup to evaluate the role of specific genes in sickle cell disease symptoms.
“Ultimately, we have three objectives,” DeBaun said. “We want to treat patients with the best available therapy and we want to characterize lung disease and sleep problems and understand them at the cellular, molecular and genetic level in this vulnerable population.”
In addition to DeBaun and Strunk, the research team will include the University’s Jessica Boyd, M.D., Mario Castro, M.D., Ping An, M.D., Anne Bowcock, Ph.D., and Michael Province, Ph.D., along with a team of investigators from Case Western Reserve University, the Medical College of Wisconsin and the Institute of Child Health in London.