Clues in Gene Expression  In research funded by the Arthritis
Foundation, Dr. Loeser and Wake Forest colleagues Jacquelyn
Fetrow, PhD, Michael Callahan, PhD, and Cristin Ferguson, MD,
along with Cathy Carlson, DVM, PhD, at the University of
Minnesota, are studying aging in knee joints with a mouse model
of post-traumatic osteoarthritis. They want to find out which
genes are turned on and off as OA takes hold in young versus old
mice. Examining the pattern of this gene expression may show the
key genes responsible for development of OA in aging.  The
researchers used mice in two age groups: 12 weeks (an age
comparable to human teenagers), and 12 months (an age comparable
to people in their 40s or 50s), when OA starts to develop.  The
group used experimental surgery that mimics a meniscus injury
(damage to the crescent shaped cartilage that cushions the knee)
and starts the knee on a path to post-traumatic OA. People under
age 30 who suffer a meniscus injury take twice as long to
develop OA than if the same inj