FORT LAUDERDALE, FLA. — People with symptomatic osteoarthritis can be differentiated from those with only radiographic evidence of disease using a combination of biomarkers, according to a study presented at the World Congress on Osteoarthritis.
Olga V. Nemirovsky, Ph.D., a researcher at Pfizer Inc. in St. Louis, and her associates, compared a large number of biomarkers of joint matrix protein degradation and synthesis and biomarkers of inflammation using urine, serum, and plasma samples from 83 participants.
Their aim was to identify biomarkers that would indicate any initial efficacy of disease-modifying osteoarthritis drugs for future clinical trials.
Participants included 22 people with symptomatic osteoarthritis; 30 people with only radiographic evidence of disease in their hip and/or knee joints; 19 with only radiographic evidence in their hand and/or spine joints; and 12 controls with no symptoms or radiographic signs of disease.
“We tried to assess each biomarker separately. Then we evaluated combinations of two biomarkers, and then applied multivariate analyses to all biomarkers,” said Dr. Nemirovsky.
Five markers contributed the most to the distinction between symptomatic patients and the others: plasma procollagen type III N-terminal propeptides (PIIINP), prostaglandin PGE2, 15-hydroxyeicosatetraenoic acid (15-HETE), collagen type II neoepitope (TIINE), and procollagen type II N-terminal propeptide (NPII). Although analysis of individual markers revealed significant differences, a combination of markers proved superior to any single assay.
Patients with symptomatic osteoarthritis had significantly higher levels of urinary C-terminal telopeptides of type II collagen (CTX-II), TIINE and collagen type III neoepitope (TIIINE) levels, osteopontin, plasma procollagen type I (PINP), prostaglandin PGE2, 15-HETE, and 3-nitrotyrosine (3-NT) compared with other groups, Dr. Nemirovsky said at the meeting, which was sponsored by the Osteoarthritis Research Society International.
On the other hand, the researchers found significantly lower levels of plasma NPII and urinary aggrecan neoepitope (Agg) in the symptomatic group.
Levels of Agg were higher for the group with radiographic disease in the hip/knee compared with the no-radiographic-evidence group or the symptomatic patients. The researchers used a model to distinguish the patients with radiographic evidence of hip/knee osteoarthritis from the radiographic hand/spine and no-radiographic-evidence groups.
The markers that contributed most to this distinction were Agg, TIINE, PIIINP, PGE2, and 15-HETE.