Protein is essential for the growth and functioning of the body, and muscle
building. Protein molecules are comparatively larger and hence cannot pass
through the glomeruli in the kidneys. They are thus retained in the blood when
waste materials and toxic substances are filtered by the kidneys. Then how does
protein appear in urine? What does high protein in urine mean? Here is an
overview of the condition called 'proteinuria'.
The kidneys' primary function is to maintain the fluid balance in the body
and to excrete unwanted soluble chemicals. While doing this, the kidneys must
conserve other important constituents circulating in the bloodstream.
Although healthy people do pass small amounts of protein in the urine
normally, above a certain level suggests that there may be damage to the filter
mechanism (the glomeruli) or inflammation.
A second source of protein in urine is blood that may come from any part of
the kidney or urinary pathway.
High levels of protein in the urine may therefore be due to diseases of the
kidney such as glomerulonephritis. It may also be due to general illnesses that
also affect the kidney as in high blood pressure .
Proteinuria can be divided into functional proteinuria and pathological
proteinuria. Functional proteinuria, also known as physiological proteinuria,
refers to the temporary proteinuria in healthy people. More common in young
people under the influence of strenuous exercise, fever, high temperature,
chills, mental stress and other factors, renal vasospasm or hyperemia, resulting
in the glomerular filtration membrane permeability-increasing protein leaving
large number of "slipping through the net". Protein in normal urine of pregnant
women increased slightly, to increase this position and renal flow, glomerular
filtration rate of the increase. Functional proteinuria proteinuria incentive to
lift will go away. It is also known as reversible proteinuria or transient
proteinuria.
If it is pathological proteinuria, it is more dangerous. Proteinuria more
than just a huge loss of nutritional protein, but also on the glomerular,
tubular, and will cause damage. Proteinuria is an independent risk factor for
causing uremia, proteinuria greatest harm is that drug eclipse kidneys, causing
uremia.
(1) proteinuria in mesangial toxicity:
Renal failure model, the observed accumulation of serum proteins in
glomerular mesangial mesangial cell injury can cause these macromolecules in the
accumulation of mesangial proliferative the faculties membrane matrix synthesis,
resulting in renal ball sclerosis. Glomerular proteinuria in the nephrotic
model, these aggregation of low density lipoprotein (LDL) and very low density
lipoprotein (VLDL) apolipoprotein B and apolipoprotein A deposition and
ultimately can lead to glomerulosclerosis.
The toxic effects of proteinuria on proximal tubule cells (2):
Proteinuria, enter the amount of protein within the renal tubular epithelial
cells to increase lysosomal activity increases caused by prompt protein the
lysosomal spilled into the cytoplasm of the tubule, subsequent cell injury can
stimulate inflammation and scar formation.
(3) proteinuria-induced tubular cell biological changes in renal disease:
proteinuria, there are cell hyperplasia, representing a non-adaptive responses,
leading to renal failure. More and more evidence to show that the protein can be
directly conditioning tubule cell function, to change its growth characteristics
of cytokines and matrix proteins phenotypic expression, the basal side of the
tubule can lead to release of PDGF, FN and MCP-1 induced fibrosis.
(4) proteinuria caused by tubulointerstitial hypoxia emphasis: the
proteinuria reabsorption digest a lot of protein extra energy, can cause tubular
cell hypoxia, resulting in the tubule cell injury.
