Glycosylation of α1-acid glycoprotein (orosomucoid) in health and disease:: Occurrence, regulation and possible functional implications

alpha(1)-Acid glycoprotein (AGP) is an acute-phase glycoprotein with five N-linked glycans, exhibiting substantial heterogeneity in their structures. This heterogeneity results from the presence in plasma of various distinct AGP glycoforms of which the plasma levels, and thus the relative occurrence of these glycoforms, are strictly dependent on the pathophysiological condition determined by cytokines and hormones. These humoral factors induce changes in the glycosylation process of the parenchymal liver cells, which are independent of the rate of synthesis of the AGP aglycon. Results are reviewed regarding the characterization and regulation of the changes in glycosylation of AGP under various physiological and pathological states, as well as the possible anti-inflammatory effects of different AGP glycoforms.