Background Successful anti-TNF-α treatment of rheumatoid arthritis (RA) causes a decrease in inflammation with reduced blood flow in the synovial tissue of the affected joints. Ultrasound Doppler (USD) is used as an estimate of the amount of blood flow in a tissue and is sensitive to measurements of small blood vessels. USD is used as a marker of disease activity in RA, where inflammation causes forming of new small blood vessels. Vascular Endothelial Growth Factor (VEGF) is suspected to be a main player in angiogenesis during inflammation. A role of VEGF in the pathogenesis of RA is supported by elevated serum levels in RA patients compared to healthy controls.
Objectives In a cohort of anti-TNF-α treated RA patients, to investigate if a change in USD signal following treatment over a year is associated with change in VEGF, and if VEGF is correlated to disease activity.
Methods 73 out of a cohort of 109 RA patients in anti-TNF-α treatment (adalimumab, etanercept or infliximab), 53 women and 20 men, age 57±13 years, with inflammation of wrist joints were assessed prior to starting anti-TNF-α therapy, and following treatment. USD examination was carried out on the most affected wrist, and fasting blood samples were collected, with no prior strenuous physical activity, at baseline, and after 180 days and 1 year of treatment. USD was measured as colour fraction (CFMean), and VEGF was measured by ELISA (Platinum, Bioscience) in EDTA-plasma at each time point. DAS28CRP was determined. Linear regression was applied, using Pearson's correlation coefficient and a significance level at 0.05.
The study was approved by the local ethics committee (KF01-045/03).
Results Full data set was available for 64 patients at 180 days and for 58 patients at 1 year. DAS28CRP at baseline was 5.1±1.3. VEGF was in the range earlier reported for RA patients. No correlation was found between CFMean and VEGF at baseline (R2=0.006; P>0.05), or in change in CFMean and change in VEGF at 180 days (R2=0.0016; P>0.05) and 1 year (RCRP and VEGF at baseline (R2=0.05; P>0.05).
Conclusions In our cohort of RA patients, no correlation was seen between VEGF plasma level and USD activity in an affected wrist joint prior to start of an anti-TNF-α of treatment, or between changes in USD and changes in VEGF following 180 and 365 days of treatment. At baseline VEGF level did not correlate to DAS28CRP either. These results do not support a role of VEGF, although important for angiogenesis, as a determinant for the increased perfusion in RA.
Acknowledgements The study was supported by the Danish Rheumatism Association and the OAK Foundation
Disclosure of Interest None declared