OBJECTIVES: Resistin is an adipocytokine that has been related to inflammation 
and insulin resistance. Following knee injury, elevated levels of resistin have 
been found in synovial fluid (SF) while very little is known about the role of 
resistin in osteoarthritis (OA). The aim of the present study was to investigate 
resistin levels in OA joints and to determine if it is associated with 
inflammatory and catabolic factors in the joints.
METHOD: SF, plasma, and cartilage samples were collected from 88 OA patients 
undergoing knee replacement surgery. Resistin levels were measured by 
enzyme-linked immunosorbent assay (ELISA) in SF, plasma, and cartilage culture 
media.
RESULTS: Significant levels of resistin [0.75 (0.67) ng/mL; median (IQR)] were 
found in SF from OA patients. Resistin correlated positively with interleukin 
(IL)-6 (r = 0.39, p < 0.001) and with matrix metalloproteinases MMP-1 (r = 0.31, 
p = 0.004) and MMP-3 (r = 0.24, p = 0.024) in SF. Resistin was also released 
from cultured OA cartilage and it correlated with resistin levels in SF (r = 
0.39, p < 0.001). In addition, resistin levels in plasma correlated positively 
with those in SF (r = 0.44, p < 0.001). There were no differences in SF or 
plasma resistin concentrations between females and males or between non-diabetic 
and diabetic patients, and resistin did not correlate with body mass index 
(BMI).
CONCLUSIONS: Resistin is present in OA joints and is released from OA cartilage. 
Levels of resistin in SF are associated with inflammatory and catabolic factors, 
suggesting that resistin has a role to play in the pathogenesis of, and as a 
possible drug target in, OA.