Quantification of Oligomeric Forms of Adiponectin Using Near‐Infrared Fluorescence

Adiponectin circulates in three oligomeric forms [low (LMW), medium (MMW) and high (HMW) molecular weight] and differential regulation of these oligomers has been reported in conditions of chronic inflammation such as diabetes. Quantification of adiponectin oligomers is generally achieved using chemiluminescence, yet near‐infrared (NIR) fluorescent technology may provide a more sensitive detection method for the imaging of biological targets. The aim of this study was to test the utility of NIR for the detection and quantification of oligomeric forms of adiponectin. Native serum (n=26) was separated on 4–15% gradient SDS‐PAGE under non‐denaturing conditions. Absolute quantification of HMW (>250 KDa) was reported linear from 16 to 125pg. The adiponectin monomer (30kDa) was reported linear from 31 to 250ng. Spearman's correlation revealed good reliability in band quantification of total, HMW and MMW, but significant variability in quantification of LMW (p<0.001). Total adiponectin correlated as expected with clinical markers of metabolism (BMI, r = −0.47; fasting insulin, r = −0.36; and homeostatic model of insulin resistance, r = −0.34). In summary, quantification of adiponectin using NIR appears to be a valid method that correlates appropriately with clinical markers of metabolism. This study was sponsored by Cornell University. Grant Funding Source : Cornell University