Nephropathy urine albumin

Although not a quantitative measure of renal function, urinary microalbuminuria has been identified as an early marker of renal disease in patients with diabetic nephropathy and numerous other conditions, such as hypertension and obesity. Patients with microalbuminuria (30 to 300 mg/day) on at least two occasions or overt albuminuria (>300 mg/day) should begin to receive pharmacotherapy. For children, microalbuminuria is considered present if albumin excretion exceeds 0.36 mg/kg per day, and overt albuminuria has been defined as an excretion rate that exceeds 4 mg/kg per day. The urinary albumin creatinine ratio is also an accurate predictor of 24-hour proteinuria, a marker of renal disease. Guidelines for monitoring indicate that a urine albumin creatinine ratio of >30 mg/g places the patient at increased risk of developing diabetic nephropathy and is an indication for the initiation of pharmacotherapeutic intervention. Microalbuminuria has also been suggested as a risk factor for renal dysfunction among patients with essential hypertension. ... 

Until late in the course of hypertensive nephropathy, renal damage is asymptomatic and laboratory findings are subtle. The first objective sign of renal involvement is a small increase in the amount of albumin in the urine. 

Transferrin, fhe iron-transporting protein, occurs in urine at concentrations that are about 15 times lower fhan that of albumin. The protein has a shghtly larger effective molecular radius (around 4.0 run) than albumin (3.6 run). Its detection in fhe urine allows a more sensitive indicator of early glomerular involvement in some nephropathies such as cadmium nephropathy. A strong association has been found between the presence of albumin and transferrin in fhe urine of patients with fhe nephrotic syndrome. In these patients, increased transferrin synthesis is insufficient to compensate for urinary losses and plasma levels are reduced [94]. 

It has been clearly recognized that one of the clinical hallmarks of diabetic nephropathy is proteinuria in excess of 500 mg/24 hours this can be easily detected by urine dipstick testing, which has a detection limit of 150-200 mg/liter of albumin. Such clinical proteinuria portends a progressive decline in kidney function leading to end-stage renal failure over an average 7-year period. This clinical proteinuria is not sudden but is preceded by years of microalbuminuria. Thus microalbuminuria represents an early manifestation of diabetic kidney disease. In fact, 6-20% of patients with IDDM present with microalbuminuria. Left uncontrolled, albumin excretion in microalbuminuric subjects can increase at the rate of 7-18.6% per year. 

Albumin is the major urinary protein in many species however, rodents have other MUPs that exhibit polymorphism. These proteins are synthesized by the liver and filtered into the urine of adult male mice and rats adult female rats excrete much smaller amounts of these proteins. Alphaju-globulin found in male rat urine with a molecular mass of approximately 18 kDa is freely filtered at the glomerulus and can be reabsorbed in the proximal tubule. This protein is also found in female rat urine, but at much lower concentrations. Proteinuria is common among aging rats as a result of progressive nephropathy, and this may complicate interpretation of results during the second year of a chronic study. 

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