Albumin is the most abundant protein (65 kDalton) in human blood plasma. After being produced by the liver, albumin circulates as a polypeptide chain of 585 amino acids which is cross-linked by 17 disulphide bonds. Albumin contributes to about 80% of the colloid osmotic pressure, and it binds a variety of both self and non-self ligands such as hormones, fatty acids and drugs. Since the 1980s, it is known that the excretion of very small amounts of albumin in the urine (20-200 mg/L or 30-300 mg/day), so called microalbuminuria, predicts the excretion of large amounts of proteins in the urine (proteinuria) in patients with diabetes mellitus. A few years later, microalbuminuria was also proven to be a powerful predictor of mortality in these patients. The clinical application of microalbuminuria as a laboratory risk marker is, to date, restricted to patients with diabetes mellitus. However, recent scientific research has shown that microalbuminuria is also an independent predictor of cardiovascular diseases and mortality in the general population. The underlying mechanism of these results is thought to be generalized endothelial dysfunction, expressed by the kidneys, resulting in ‘leakage’ of albumin into the urine. This endothelial dysfunction can be caused by risk factors such as high bloodpressure, smoking, obesity, and diabetes. Cardiovascular diseases are the leading cause of death in the Western world. The screening for subjects with an increased risk for cardiovascular diseases is therefore of utmost importance. In this respect, the detection of albumin in the urine plays a very important role. In this thesis we describe the effects of frozen storage of urine samples on the measured albumin concentration (part I). We furthermore explore the different methods of measurement that play a role in the assessment of albumin in urine (part II).
|Kwalificatie||Doctor of Philosophy|
|Gedrukte ISBN's||9789036730907, 9789036731072|
|Status||Published - 2007|