EXPERIMENTAL BIOLOGY UPDATE: Arthritic kids' iron supplements may hasten joint deterioration
By Diana Swift
WWASHINGTON, D.C. - The iron supplements that many arthritic children take to combat concomitant anemia may be hastening the deterioration of their joints, Houston researchers say.
Led by biologist Roman Shypailo of the Children's Nutrition Research Centre at Baylor College of Medicine, a Texas team looked at eight children being treated for juvenile rheumatoid arthritis. The patients, aged five to 15 years, received an intravenous radioactive tracer dose of iron (0.03 microsievert). Iron activity in affected joints was monitored on a position/energy-sensitive gamma counter, while a second machine monitored whole-body iron retention. Iron deposition was measured two hours post-infusion and again at days seven, 14, 28 and 56.
Anemic
"We found that iron excessively accumulates in arthritic joints and probably contributes to the chronic damage," said Shypailo. "That puts you between a rock and a hard place because many of these arthritic kids are anemic and need iron supplements, which may worsen the disease."
The study found a high level of agreement between the joint data and the whole-body data, with a greater than 90% retention rate of the infused iron both in joints and systemically. Furthermore, six of eight patients showed increased uptake at the affected joints: 165% over the first 30 days compared with initial uptake at two hours.
The next step, he says, is to see if there is excessive deposition of dietary iron in arthritic joints.
IRON DEPOSITION IN THE JOINTS OF CHILDREN WITH JUVENILE RHEUMATOID ARTHRITIS
Author(s):
SHYPAILO ROMAN J
ELLIS KENNETH J
PEREZ MARIA
ABRAMS STEVEN A
Interpretive Summary:
We wanted to develop an accurate and noninvasive way of
determining the amount of iron deposited in the joints of
patients with juvenile rheumatoid arthritis. Children with JRA
often develop excess iron in their joints, so doctors need a
way of monitoring the iron level, particularly when prescribing
iron supplements for the common problem of anemia. However, the
only method currently available is to take a biopsy. We adapted
a machine called a gamma counter to measure the iron in eight
patients' joints after giving them an iron isotope by vein.
Then we compared the results with the total amount of iron in
their bodies, measured by a whole-body counter. We found that
we had developed an accurate new way of measuring iron in these
patients' joints. We also found that six of the eight subjects
had excess uptake of the iron isotope in their joints. That
provided a signal that a preponderance of JRA patients are
prone to have this problem, and clinicians should take special
care to monitor them for it. Moreover, this is the first time a
noninvasive way of performing this measurement has been
available.
Keywords:
energy reproduction growth body composition women infants
children water potassium bioelectrical impedance conductance
bromide space lactating iron adipose tissue lipid motabolism
beta-adrenergic receptor cell culture neutron activation
nitrogen carbon calcium sodium chlorine phosphorus hormonal
changes differentiation adipocyte hnrim021125
