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Human albumin: benefits


Human albumin: indications and clinical benefits


The package inserts of albumin solutions in Europe follow the Summary Product Characteristics developed by the European Medicines Agency and endorsed by the national health authorities. It is currently being reviewed by the European health authorities whose approval is scheduled for 2013


Christian J Wiedermann MD FACP Associate Professor of Internal Medicine, Medical University of Innsbruck, Director, Department of Internal Medicine, Central Hospital of Bolzano, Italy Email: christian.wiedermann@asbz.it


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Albumin is the most abundant plasma protein in the human body, alone constituting about 55% of the total protein content of plasma. It is formed by a single polypeptide chain of 585 amino acids with a molecular weight of 66,500 Dalton, synthesised entirely by the liver. Of the total content of albumin (about 250–350g for a healthy 70kg adult), approximately 42% is located in the intravascular compartment, and its half-life is about 20 days.1 Albumin is a multifunctional protein with both colloidal and pharmacological activity. The exchange of fluids between the intravascular and extravascular compartments is basically governed by the levels of hydrostatic and oncotic pressure and the degree of capillary membrane permeability. Albumin’s colloidal activity is essential in maintaining fluid balance between the intravascular and interstitial compartments. Because it is the predominant plasma protein, albumin accounts for approximately 75–80% of plasma colloid osmotic pressure (COP). Due to the presence of several histidine residues with an acid dissociation constant very similar to the plasma pH, albumin is an excellent buffer in plasma as well as the main extravascular buffer able to donate positive and negative charges in case of alkalosis and acidosis, respectively (see Box 1). In addition, albumin is endowed with diverse biologically specific capabilities such as ligand binding,


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"Human albumin may be preferentially used in cases where a sustained action on the blood volume is required or when there is a contraindication for non-protein colloids”


antioxidant, free radical-scavenging and anti-inflammatory activity, inhibition of apoptosis and cell signalling.1 Albumin specifically binds to a wide array of endogenous ligands, including metabolites, lipids, hormones, metal ions and high-affinity endothelial cell albumin receptors.2


Ligand binding itself may


serve multiple purposes such as transport, sequestration and transcytosis. Additionally, albumin binds numerous administered drugs and in many cases can modify their bioavailability and pharmacokinetics.3


administration results in increased effects of loop diuretics by augmenting drug delivery to the renal tubule.4


Evidence For example, albumin


concerning these non-oncotic pharmacological properties of albumin continues to accumulate rapidly. Albumin plays a modulating role in haemostasis due to binding between sulfhydryl groups of albumin and nitric oxide (NO), thus slowing the inactivation of NO, which exhibits anti-aggregating effects on platelets and has vasodilator properties.5 Albumin contributes to the maintenance of normal permeability of capillaries to


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