Bone loss seen in kids after stem cell therapy

By David Douglas

NEW YORK (Reuters Health) – A type of stem cell therapy
called hematopoietic cell transplantation (HCT) often leads to
a reduction in bone formation in children, according to
Minneapolis-based researchers. HCT is used to treat cancers of
the blood such as leukemia.

Dr. Anna Petryk and colleagues at the University of
Minnesota studied the impact of HCT on bone health in 64
children aged 5 to 18 years who had undergone HCT at their
institution.

“Bone mineral density (BMD) is reduced after HCT,” Petryk
reported to Reuters Health.

Specifically, she and colleagues found that the proportion
of children with osteopenia — a bone-thinning condition just
short of osteoporosis — increased from 18 percent at baseline
to 33 percent at 1 year after HCT, while the rate of full-blown
osteoporosis increased from 16 percent to 19 percent.

The “absolute loss of bone mineral” corresponded to a 5.3
percent reduction in BMD at the lumbar spine, the researchers
report.

Nevertheless, not all subjects were equally affected, and
in some cases bone mineralization was not affected at all.

The study also shows, Petryk noted, that the level of
osteocalcin, “a blood marker of bone formation, may be
predictive of recovery from the initial bone loss.” Osteocalcin
levels greater than 6.5 ng/L at 100 days predicted recovery
from the initial bone loss at 1 year.

These findings, said Petryk, have implications for the
treatment of osteoporosis in children. The medications that are
typically being used in adults with osteoporosis inhibit the
harmful process of bone resorption. “However, we did not find
an increase in resorption in children; we found that bone
formation was reduced,” she said.

“Therefore,” she concluded, “it is critical to determine in
future studies whether bone resorption is increased in children
or not because that will determine what treatment would be
appropriate.”

SOURCE: The Journal of Clinical Endocrinology and
Metabolism, March 2006.

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