Adiponectin, Adipokines, and the Need for Long-Term Human Studies With Comprehensive End Points.

Abstract

Adiponectin is arguably the adipokine most specifically expressed in white adipose tissue. It was described in 1995 as Acrp30, AdipoQ, apM1, and GBP28. The x-ray crystallographic observation in 1998 that there was structural homology to complement C1q and tumor necrosis factor should have been a clue that this would be a complex beast.1 Adding further to the complexity, adiponectin monomers are assembled into multimers that can be separated by size into 3 broad groups. The largest high-molecular weight adiponectin has been shown to be protease resistant, which became the basis for a selective immunoassay.2 The complexity of adiponectin structure—with both covalent and noncovalent interactions stabilizing the multimers—adds further challenges to quantification for patient–based studies. Indeed, not all assays have been found to give agreement. In the absence of a gold standard, we require stability from suppliers of assays and carefully characterized cohorts to establish biovalidation. See accompanying article on page 2259 Advances require that not all evidence be accrued in human or patient–based studies. Adiponectin has proven a challenge, as while it is found in species such as mice, there are major species-specific differences in tissue expression patterns3 (Biogps GeneAtlas …