Glycated Albumin, An Early Biomarker of Several Pathologies

Abstract

The role of glycated albumin is determinant for early diagnosis in several pathologies. Obviously, it is with glycated hemoglobin elective for Diabetes diagnosis but the ratio albumin glycated and hemoglobin glycated could support the in vitro diagnosis in several pathologies of CNS such as Parkinson Alzheimer diseases and Epilepsy. Mini ReviewHuman serum albumin, produced as preproalbumin is modified as mature albumin and secreted by the hepatocytes controlled by the gene localized on chromosome 4 [1,2]. It is present largely in human blood, about 50% of the others circulating protein displaying a concentration ranging from 30 g/L to 50 g/L in nonpathological subjects. On the contrary, its Molecular weight is 67 KDa resulting lower than other proteins [3]. Are present 585 aa constituting III domains each of them sub classified in two domains, A and B [2]. These domains give an alpha helix structure. Among Domains A and B are reported 17 bounds Cyst-Cyst whereas Cyst 34 is unbounded. This protein folding permits to react versus pH changes and other biophysical changes [4]. Useful oncotic pressure is due to electrical point (pI)of the protein giving a distributed negative charge [5,6]; moreover, albumin binds reversibly metabolites, ions, fatty acid, bilirubin and drugs regulating the drug delivering [7][8][9]. Finally, albumin modulates the oxidative stress in plasma acting with free Cyst-34 [10,11]. Non-Enzymatic Glycated AlbuminThe high albumin serum concentration and the moderate half-life (t1/2 = 21 days) with respect the other serum proteins is highly sensitive to direct glycation reaction. This is Maillard's reaction is glucose and free amine group of albumins giving a labile intermediate "Shiff base" that rearranges itself (Amadori mechanism) giving fructose-amine derivatives displaying moderate stability [12,13]. Both Shiff base and fructose-amine derivatives are the preliminary products of glycated albumin [14]; however, the last one could give heterocycles such as piranosyl-and furanosyladducts [15]. Other pathways could give, due to several oxidative or cleavage or re-modelling processes, stable compounds so called AGE (Advanced Glycation End product) [16].