Concerns about the diabetes drug
Avandia continue to mount in the wake of a recent study
linking Avandia with accelerated bone loss and osteoporosis.
In the report, published in the December 2007 issue
of Nature Medicine, researchers from the Salk Institute
in La Jolla, California report that rosiglitazone (Avandia)
has been shown to interfere with the formation of new
bone tissue in mice and warn that long-term use may
speed up osteoporosis.
Bone tissue is constantly regenerated
in a process known as bone remodeling. Bone remodeling
utilizes two specialized cells – osteoclasts
and osteoblasts – which
work in unison to support bone integrity. Osteoclasts initiate the remodeling
process by secreting an acid-like substance to dissolve old, weakened bone, leaving
behind a series of small pits or cavities. Once this is complete, the osteoblasts
move in to fill the cavities with a collagen mixture that hardens to form new
bone.
Maintaining healthy bone mass depends
on the body’s ability to maintain
a state of equilibrium between bone destruction and bone replacement. When
this balance is disrupted, as in the case with osteoporosis,
bone remodeling is impaired,
resulting in weakened, brittle bone.
The Salk researchers found that Avandia
stimulates the production of osteoclasts that degrade
bone tissue without an equivalent increase in activity
by osteoblasts.
What the US researchers have shown is that, in mice receiving the drug, the
increased activity from osteoclasts throws the remodeling process out of equilibrium,
ultimately
tipping the balance towards bone loss.
Commenting on the findings, the researchers
noted that, “These findings
have potential clinical implications, as they suggest that long-term rosiglitazone
usage in the treatment of Type 2 diabetes and insulin resistance may cause
osteoporosis, owing to a combination of decreased bone
formation and increased bone resorption.”
Despite
growing concern over the wisdom of using Avandia for the treatment of diabetes,
a number of potential benefits have turned up. Avandia has been shown
to reduce cancer in several studies, and ironically its role in promoting osteoporosis
may ultimately lead to new insight into the disorder.
Source: Diabetes
Drug Avandia Could Weaken Bones. Dec. 2, 2007, Nature
Medicine.
