Background Juvenile idiopathic arthritis (JIA) is a chronic and socially significant disease as it leads to quick disability in childhood. Metabolic processes of connective tissue are important part of pathogenesis of JIA.
Objectives It was to study dynamics of parameters of connective tissue metabolism in children with JIA against the background of standard therapy with methotrexate by the follow-up study.
Methods The study involved 65 children within 2–18 years with JIA: oligoarthritis in 39,6%, polyarticular form - 37,7%, systemic form - 20,8%, enthesitis-related arthritis – 1,9%. In serum the total level of glucosaminoglycans (GAG) and chondroitinsulfate (CS), level of chondroitin-6-sulfate as I fraction of GAG, level of chondroitin-4-sulfate as II fraction of GAG, level of heparansulfate as III fraction of GAG, calcium, phosphorus and in urine level of oxyproline, uronic acid, calcium, phosphorus were determined. Parameters were assessed depending on the duration of disease: till 1 years (19 patients), 1–2 years (17 patients), 2–3 years (29 patients). They had being evaluated over the following 3 years.
Results 77.78% of patients had decreased level of GAG in the serum. Decrease of I fraction of GAG was determined in 11.11% of patients, of II fraction of GAG -92.59% and III fraction of GAG – 96.3% of patients. Increased level of I fraction of GAG was presented in 48.15% of children. Mean general level of GAG was not difference in comparison with persons of control group and did not depend on duration of disease. Mean level of I and II fractions of GAG in patients with JIA was higher in comparison with persons of control group, beginning from 1st year of diseases development and for next 3 years (p<0.001). Mean level of III fraction of GAG was not difference in comparison with persons of control group and did not depend on duration of disease. 51.85% of patients had increased level of CS. Mean level of CS in patients with JIA was higher in comparison with persons of control group, beginning from 1st year of diseases development and for next 3 years (p<0.001). 59.26% of children with JIA had increased urinary excretion of oxyproline. The mean levels of oxyproline, uronic acid, phosphorus in urine in patients with JIA were not different in comparison with children of control group and did not depend on duration of disease. The level of serum calcium in the majority of patients (96.3%) was within the limits of norm, in urine – in 74.07% of patients was increased. The average level of calcium in urine was reliably below, than at group of the control (p <0, 01), irrespective of duration of disease.
Conclusions Changes in the exchange of connective tissue metabolism are occurred already during the first year of JIA development and presented in subsequent years, despite treatment.
Disclosure of Interest None declared