Proinflammatory cytokines, chemokine CXCL17 and heat shock proteins in osteoarthritis of the knee joint

Osteoarthritis (OA), a common multifactorial disease of musculoskeletal system, is one of the leading causes of disability in the population. One of the most important pathogenetic factors of OA is a shift of cytokine profile towards pro-inflammatory state. Their increased levels lead to dysfunction of cartilage tissue cells with its damage. Purpose of the present study was to evaluate diagnostic significance of the most important cytokine and chemokine levels involved in pathogenesis of OA. The study involved 50 patients undergoing inpatient treatment at the “Hospital for War Veterans” (Vladivostok) with an established OA of the knee joints. The following mediators involved in the development of inflammation have been determined: interleukins IL-1â, IL-6, chemokine CXCL17, tumor necrosis factor TNFá and heat shock proteins HSP27, HSP70 in blood serum of patients being analyzed by ELISA test systems. It has been shown that the levels of interleukins IL-1â and IL-6, TNFá and CXCL17 in patients with OA exceeded those for healthy individuals. The levels of cytokines IL- 1â, IL-6, chemokine CXCL17 and TNFá in blood serum of OA patients were 7.4 (6.4-8.9), 33.7 (26.5-68.4); 33.8 (29.8- 61.0) and 6.5 (4.94-8.59) pg/ml, respectively, thus significantly exceeding the values for healthy person s (1.3 (1.2-1.4), 5.8 (4.2-6.3), 24.9 (19, 1-29.9) and 2.7 (2.1-3.1) pg/ml, p 0.05). In OA patients, the concentration of TNFá had a direct relationship with the chemokine CXCL17 (r = 0.83, p 0.05). The concentrations of heat shock proteins HSP27, HSP70 and their ratio were significantly lower in patients with OA compared to the control group (respectively: z = -3.06, p = 0.002; z = -4.41, p = 0.00001; z = -2.05, p = 0.04), thus allowing us to suggest the tolerance of chondrocytes to the influence of cytokines. At the same time, the concentration of HSP70 decreased as the disease progressed, while the level of HSP27 did not change significantly. Thus, determining the level of systemic intercellular mediators enables usage of these indexes as potential biochemical markers for predicting severity of the disease and assessing their fundamental role in pathogenesis of knee OA.