Potential new indicators of lupus being studied in children
What is the topic?
Since the 1970s, researchers have known that lupus patients are at risk for hardening of the arteries ("atherosclerosis"). Some of this risk may be from the increased inflammation that lupus patients have in the bloodstream over many years, but some of it is from the same reasons that hold true for everybody: especially high blood pressure, high blood sugar, or low levels of "good cholesterol." Taken together, these risk factors are known as "metabolic syndrome," a condition that puts people at high risk for heart disease, diabetes, or both. Some of the medications that lupus patients may take can increase the likelihood that a person will develop metabolic syndrome, especially prednisone.
Cells in the body release specialized chemicals called "cytokines," molecules that carry messages between nearby cells, and some of these messages work specifically to influence body weight and how fast food is burned or whether it turns into fat. If the cytokine messengers are sent out by fat cells, they are called "adipokines." The names of some of these adipokines (fat cell messengers) are leptin, adiponectin, and ghrelin.
What did the researchers hope to learn?
The researchers wanted to find out whether the amount of leptin, adiponectin, or ghrelin in children with lupus might be different than in children without lupus.
Who was studied?
105 children with lupus and 77 healthy children from Toronto, Canada took part in this study. About 20% of the lupus patients were boys and about 80% were girls. The healthy children were a little younger and about 27% of them were boys.
How was the study conducted?
The researchers collected blood samples from the children after they had not eaten overnight. They measured the levels of leptin, adiponectin, and ghrelin (fat cell messengers). It was important to do these studies on blood samples taken from participants who had not eaten for a number of hours, because the nutrients that enter the bloodstream from food can have a big effect on the levels of these fat cell messengers.
What did the researchers find?
The researchers found that children with lupus have more leptin in the blood than healthy children. This was not affected by how severe the lupus disease activity was at the time the blood sample was collected, or by the dose of prednisone being taken.
There was no difference between the groups in the levels of adiponectin or ghrelin. Adiponectin levels were affected by the cholesterol levels in the blood or the dose of prednisone being taken.
What were the limitations of the study?
The finding that levels of two possible risk factors for atherosclerosis may be higher in children with lupus could be very important, but does not differentiate whether this results from lupus or its treatments.
The effects of the diet a child was eating over an entire month, their kidney function, or other medications they might have been taking could not be looked at in a study this size, but might have had some impact on the outcome.
What do the results mean for you?
Hardening of the arteries takes a long time to develop, and some studies suggest that some of the risk factors can begin to have an impact in childhood. The finding of these risk factors in children with lupus may begin to explain why some lupus patients develop heart disease relatively early in life and, most importantly, could provide a marker to follow so that preventative measures can begin early.
Adipokines as novel biomarkers in paediatric systemic lupus erythematosus. (2009).
Authors: Al M, Ng L, Tyrrell P, Bargman J, Bradley T, and Silverman E.
Rheumatology 48: 497-501.