Synovial fluid omentin-1 levels are inversely correlated with radiographic severity of knee osteoarthritis.
OBJECTIVE
The purpose of this study was to demonstrate omentin-1 levels in serum and synovial fluid (SF) of patients with knee osteoarthritis (OA) and to investigate their correlation with radiographic disease severity.


METHODS
One hundred and ninety-seven patients with OA and 65 sex- and age-matched healthy controls were enrolled in this study. The radiographic disease severity of OA was assessed by the Kellgren- Lawrence (KL) grading system. The omentin-1 levels in serum and SF were determined by enzyme-linked immunosorbent assay.


RESULTS
There were no significant differences in serum omentin-1 levels between patients with OA and healthy controls (P>0.05). There were also no significant differences in serum omentin-1 levels among patients with OA with different KL grades (P>0.05). However, SF omentin-1 levels decreased significantly as the KL grades increased (KL grade 4 < KL grade 3 < KL grade 2; all P<0.01) in the patients with OA. Furthermore, SF omentin-1 levels were negatively correlated with KL grades (r=-0.643; P<0.001). Multinomial logistic regression analysis revealed that there was still a negative correlation between the SF omentin-1 levels and the KL grades after adjusting for confounding factors (P<0.001).


CONCLUSIONS
Synovial fluid omentin-1 levels showed an independent and negative correlation with radiographic severity of the disease in patients with knee OA. Omentin-1 in SF might serve as a potential biomarker for reflecting the degenerative process of primary knee OA.
Traumatic Orthopaedic Department, Yuhuangding Hospital, Yantai, PR China.
Lin
L
Xu
Guang-bin
GB
Zhu
Lei
L
Wang
Dan-feng
DF
Wang
Xiao-rui
XR
Jiang
D000368:Aged; D015415:Biomarkers / Q000097:blood / Q000378:metabolism; D016022:Case-Control Studies; D003430:Cross-Sectional Studies; D016207:Cytokines / Q000097:blood / Q000378:metabolism*; D005260:Female; D058851:GPI-Linked Proteins / Q000097:blood / Q000378:metabolism; D006801:Humans; D037102:Lectins / Q000097:blood / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000097:blood / Q000000981:diagnostic imaging* / Q000378:metabolism*; D011859:Radiography; D012720:Severity of Illness Index; D013582:Synovial Fluid / Q000378:metabolism*
D015415:Biomarkers; D016207:Cytokines; D058851:GPI-Linked Proteins; C432397:ITLN1 protein, human; D037102:Lectins